Annex I: ENVIS Partner meetings - Springer LINK

Annex I: ENVIS Partner meetings

12and13 April 1996 FirstPartner meeting In Cascais, Portugal

Participants

ElM, the Netherlands



TNO-STB, the Netherlands

Bocconi University, Italy

University of Brighton, UK

Roskilde Univers ity, Denmark

IAPMEI, Portugal

Portugal

European Commission, DG XII, Belgium

Koos van Dijken

Yvonne Prince

Cisca Snel

Teun Wolters

Marco Frey

Sandra Meredith

S"ren Kerndrup

Mariano dos Santos

Eduardo Lopes Rodrigues

Ola Siksio (scientific officer of our project)

Discussed

• Organ isational aspects (project management, board of contractors, steering commit

tee, theme co-ord inators, newsletter, workshops, external policy and scientific review

panel)

• Financial aspects

• Dissemination of the ENVIS-results

• Consortium agreement between partners and project co-ordinator

• Choice of sectors

The four sectors that are selected are industrial painting , textile, printing and treatment

and coat ing of metals (electroplating).

• Activities per country of the exploratory stage

- state of the art of innovations: literature research (CENTRIM, UK)

- technological trajectories in the sectors (TNO, NL)

- sector descriptions and role of SMEs (IAPMEI , PT)

- environmental policies (Bocconi Univers ity, IT)

• Deadlines and time schedules

27 and28 September 1996

Participants






second Partner meeting In Roskllde Denmark

Koos van Dijken

Yvonne Prince

Cisca Snel

Teun Wolters

Paul Kalff

215

Adoption of Environmental Innovations



Roskilde University, Denmark

IAPMEI, Portugal

European Commission, DG XII, Belgium

SpecialguestMinistry of Housing, Physical Planning

and Environment, the Netherlands

Vittorio Biondi

Sandra Meredith

Seren Kerndrup


Ola Siksi6 (scientific officer of our project)

Maurits Butter

Discussed

• Draft theme chapters of the exploratory stage

- Literature study (Centric, UK)

The goal of this study is to obtain a uniform background and to achieve a shared

foundation to empirical work.

- Technological trajectories in the sectors (TNO, NL)

In the discussion it became clear that the importance and value added of the de

scription of technological trajectories (obsolete, average, best practice, technologi

cal frontier) is, that in the qualitative and quantitative stage the best-practice firms

can be identified, that we know exactly where we are talking about with the entre

preneur technologically, and that our interviews and results can be as precise as

possible.

- Sector descriptions and role of SMEs (IAPMEI, PT)

- The sector descriptions should focus on the main topics: how important is the sec-

tor for the economy?, the heterogeneity or homogene ity of the sector , the prosperity

of the sector, the cost structure, the relations with suppliers and customers, the in

vestments in technology and the recent developments.

- Theme environmental policies (Bocconi University , IT)

This chapter should include an analysis and description how legislation is enforced

and end with a list of factors.

• Dissemination of the ENVIS results

• Deadlines and time schedules

• Presentation qualitative stage

- Concluded is to carry out the qualitative stage with a well-thought methodology,

conceptual framework, a tested checklist , a clear procedure and uniform protocol.

EIMffNO will make a procedure and carry out a pre-test. Offset printing will serve

as a pilot.

• Tasks theme co-ordinator qualitative stage (Roskilde, Denmark)

- making the format on how to report the results of the in-depth interviews

- co-ordinationlintegrating the pilot cases

- making conclusions

- think about how to analyse the qualitative reports of all interviews

216

ENVISPartnermeetings

• Topics in the checklist:

- variables/success

- sector elements, cost structure, prosperity

- legislation

- trajectories

• Selection of firms

- TNO will come up with gUidelines how to select the best-practice technologies.

• Meeting of the board of contractors

14 and15 February 1997

ParticipantsElM , the Netherlands




Bocconi University , Italy

Bocconi Univers ity, Italy

Bocconi Univers ity, Italy





IAPMEI, Portugal

IAPMEI , Portuga l

Thirdpartner meeting in Milan, Italy

Koos van Dijken

Yvonne Prince

Cisca Snel

Teun Wolters

Giuliano Mussati

Marco Frey

Vittorio Biondi

Alessandra Ferli

Fabio lraldo

Sandra Meredith

S"ren Kerndrup

Rui Gomes


Discussed

• Final remarks on the last part of the exploratory stage

• Presentation on the integrated part/synthesis and conclusions on the exploratory stage

• Country experience with pilot interviews


• Deadl ines and time schedules

• Goal of the qualitative stage

The main goal is understanding and reaching descriptive results .

The key questions that have to be more explicit in the questionnaire are:

- business characteristics (technology, organisation, environment)

- customer/market (supplie rs, stakeholders, relationsh ips)

- innovation characteristics (phase of innovation/adoption: idea, implementation, use)

- results achieved by the innovation (process perspectives, relationships)

- network relations (explic it use of the phase of innovation, stakeholders, all network

relations)

217

Adoption of Environmentsllnnovations

• Analysis plan and software- specification of requirements of software for the qualitative analysis (easy coding,

sourcetags, memory/annotation, Boolean moderators)

- we will make the reportsof the individual interviews usingthe source tag and make

a case description of eachsector

• Finalisation of the checklist

• Sectors' technology selection

fields of technological innovation

- degreasing

- reduction of rinsingwater

- cyanide reduction

- substitution of metalsin passivation of zinc

* textile finishing

fieldsof technological innovation

- reduction of dye consumption (improving of fixing ratios)

- reduction of water consumption (supercritical CO2; vacuumtechnology)

- reduction of energyconsumption

* industrial painting

fields of environmental innovation

- degreasing- reduction of rinsingwater

- reduction of organicsolvents

reduction of chemicals in waste gases (afterburner with heat exchange or powder

paint(substitution of solvent-based paints/reduction of waste gases))

* electroplating

reduction of chemicals/elimination of filmsComputer-to-plate equipment

• Dissemination

26-28June 1997

ParticipantsElM, the Netherlands





218

Fourth partnermeeting in Brighton, UnitedKingdom

Koosvan Dijken

YvonnePrince

CiscaSnel

Teun WoltersMarcoFrey




IAPMEI, Portugal

IAPMEI, Portugal

SpecialguestsMinistry of Housing, Physical Planning


Ministry of Economic Affairs, the Netherlands

INETI, Portugal

ENVISPartnermeetings

Sandra Meredith

Bent S"ndergaard

Ole Erik Hansen


Antonio Lopes

Maurits Butter

Laurens Meijering

Paulo Partidari6

Discussed

• Presentation textile case study

• Presentation electroplating case study

• Presentation printing case study

• Conclusions of the case studies so far

Focal points of the study:

- role of SMEs in environmental innovation

- the differences between countries sectors of industries and firms regarding patterns

of diffusion and sources of environmental innovation

- the importance of the institutional context and the firm's network relationships

- the connection between the diffusion patterns and the economic and environmental

results

• What do we have to do to complete the qualitative stage

• Time schedules and division of tasks qualitative stage

• Activities and deadlines


• Dissemination plan

27 June 1997 meeting with the Scientific and Policy Review Panel

Participants

Ministry of Housing, Physical Planning


Ministry of Economic Affairs, the Netherlands

INETI, Portugal

Centric, United Kingdom

SPRU , United Kingdom

Maurits Butter

Laurens Meijering

Paulo Partidari6

Howard Rush

Frans Berkhout

219

Adoption of Environmentallnnovat/ons

Discussed• Goal of the ENVIS-project and the activities carried out thus far

• Dissemination

27-29 November 1997 Fifth partner meeting in Cascais, Portugal

Participants









IAPMEI, Portugal

IAPMEI, Portugal

European Comm ission, DG XII, Belgium

SpecialguestMinistry of Economic Affairs, the Netherlands

Koos van Dijken

Yvonne Prince

Cisca Snel

Teun Wolters

Fabio lraldo

Sandra Meredith

Bent S0ndergaard

Ole Erik Hansen


Antonio Lopes

Michel Cornaert (our scientific officer)

U Young Hu

Discussed

• Presentation state of affairs

• Presentation of the analys is of the qualitative stage

• Presentation of text analys is of the qualitat ive stage

The qualitative stage results into a contextual model of innovat ion/adoption relating

three elements:

- the adopter's external network (business network , regulatory network, knowledge

network);

- the adopter's strategic orientation;

- the adopter's internal competences (motivation , knowledge, power).

• ideas about the quantitative stage

The conceptual model of the quantitative stage will be:

I = EN x EOx IC

I = innovativeness (based on actualinvestments);

EN= external network

EO= environmental orientation

Ie = internalcompetences

• meeting of the board of contractors

220~'··0

Annex II: Methodology and project design

1 Methodology

The following considerations were included in the project's methodology.

• The environmental focus of the project is to be realised by the selection of sectors with

strong environmental impacts and technologies with obvious environmental benefits .

• The focus on SMEs is to be realised by the selection of sectors with a large proportion

of SMEs.

• The selection of technologies is to be based on a technological survey which for key

elements of the main production processes in the sectors chosen identifies relevant

technological trajector ies. Within these trajectories best practice and frontier technolo

gies are to be identified.

• The project is to select traditional sectors (rather than newly emerged high-tech sec

tors), in order to draw conclusions which are relevant to a great number of SMEs.

• The project is to pay particular attention to innovation networks and their role in the

adoption process.

• There are to be case studies on the adoption of particular technologies (selected from

the technolog ical survey). For each of the four sectors, one particular technology is to

be selected and its adoption studied in each of the five countries (Denmark , Italy, the

Netherlands, Portugal, United Kingdom). Hypotheses on the adoption behaviour of

SMEs are to derived from a cross-sector analysis of the case studies.

• These hypotheses are to be tested in a broader quantitative survey among SMEs in

the four sectors and five countries involved.

• The policy implications of the findings will be comtemplated and formulated.

221

Adoption of Environmentaf Innovations

2 The project'sdesign

The project distinguishes between four stages, which are as follows .

Project design

exploratory stage

3 The exploratory stage

selection of sectors, technologiesand adoption model

20 casestudieson adoptionprocesses (4 sectorsin 5 countries)

testingof hypotheses

policyimplications andoverall conclusions

Major deliverable of the exploratory stage is a tested protocol for the case studies. The

activities involved are indicated below.

Exploratory stage

selectionof four sectors

literature and backgroundstudies (sectorsand env.

licies)

draft protocol for casestudieson adoptionprocess

222

technology study:identification of relevanttechnolo ies

Methodology andprojectdesign

4 The qualitative stage

The qualitative stage involved the case studies themselves and subsequent analysis of

the materials, both by means of a sector-based analysis of the case studies and a text

analysis of all 100 interviews. This resulted into the elaboration of the Innovation Triangle,

and the formulation of hypotheses. This is expressed in the following picture.

Qualitative stage

text analysisof 100interviews(actorsand factors)

5 The quantitative stage

The quantitative stage contains a telephone interview in order to test the hypotheses.

Quantitative stage

Indicators from the Innovation Triangle:

business competence

environmental orientation

network involvement

Questionnaire for telephone interviews

Telephone interviews with 500 SMEs4

Analysis of the data and testing of

223


6 Thefinal stage

Thefollowing elements are partof the final stage.

Final stage

Policy implicationsof national differencesin adoption behaviour

General conclusions- on methodology- project design- further research

224

Annex III Questionnaire

225

RECEPTIONIST:Goodmoming/aftemoon, this is ... of market research agency InterNiew Intemational in Amsterdam,the Netherlands. Could you put me through to the person who is responsible for investment in newmachinery or equipment. (F.I. TECHNICAL DIRECTOR, GENERAL DIRECTOR)

1. speaking2. put through3. not available -> SCHEDULE APPOINTMENT

IF RIGHT PERSON:Goodmoming/aftemoon, this is ... of market research agency InterNiew Intemational in Amsterdam ,the Netherlands. At the moment we are conducting a study about new production technologies whichare expected to have a beneficial effect on the environment. Could I ask you some questions?INT.: IF NECESSARY: The interview will take about 10 minutes to complete

1. yes, cooperates2. no, refusal3. no time now -> SCHEDULE APPOINTMENT

1a.First of all I want to check if the main activity of your company is ....INT.: READ OUT - EXPLANATION ON THE PAPER INTERVIEWER INSTRUCTION

1. offset printing (on the plate the printing areas are at the same level as the non-printingareas)

2. electro-plating (electrolytic deposition of metal layer on metal products)3. textile finishing with respect to cotton and/or synthetics4. industrial painting for third parties5. is not main activity-> TERMINATE INTERVIEW

1b.Can you tell in what sense you are involved in investments in new technologies?INT.: MULTIPLE ANSWERS ALLOWED

1. as managing director2. as member of board of directors or management team3. as production manager4. as environmenta l affairs coordinator5. as senior technician6. as controller/financial specialist7. none of these

INTERNAL COMPETENCES

2. I am going to read some statements about your business and policies. For each statement,please indicate if you fully agree, agree, disagree or fUlly disagree.

answers:1. fully agree2. agree3. don't know4. disagree5. fully disagree

227

Adoption01Environmental Innovations

Motivationza. Today our business is experiencing serious environmental pressure which needs a lot of

attention by the management2b. auality management is a major tool to survive as a business2c. Environmental quality is as important as making money2d. Legal requirements dominate our environmental affairs2e. Without investments in new equipment we will be out of business in a few years time2f. We are keen to make new Investments which are subisidised by the govemment2r. We attach great value to have a 'green image'

Knowledge2g. It is very difficult to attract skilled personnel2h We manage to keep abreast of new technologies which may change our production processes

in the coming years2i. We regUlarly involve extemal advisors so as to make sure we avail ourselves of adequate

informat ion2j. We find it hard to acquire sufficient information about how to manage our environmental affairs2k. Our employees are skilled enough to cope with environmental problems21. Customer demands are changing,therefor we find it hard to decide on what investments we

should make2m. In general, we have no difficulties in finding adequate information when deciding on new

investments2s. Our own employees do have an important contribution to innovative ideas

Power2n. Whether we adopt environmentally friendly technologies strongly depends on what our

customers demand from us20. Our financial position is strong enough to invest in new equipment,if needed to improve our

business2p. If compared to our direct competitors, our market share is highzq, Our investments in new equipment strongly depend on our annual profits

ENVIRONMENTAL ORIENTATION

3.

3a.3b.3c.

226

Now some statements about how your company deals with environmental aspects. Again, Iwant to ask you to indicate for each statement if you fully agree, agree, disagree or fullydisagree.

We have a clearly stated environmental policyWe have implemented an environmental management systemWe are ahead of legal environmental requirements (by doing more than we are obliged to)

Questionnaire

NETWORKING

4. If considering the adoption of new environmentally relevant technologies, extemal parties cangive advice and other kinds of support (f.e. financial, physical, technical, ... ) to companies.(Advice can be research information. other supporting services as audits. measurementassessments). Based on your experience do you agree that the following external parties giveuseful advice and other kinds of supPOrt to your company? Please indicate for each party if youfully agree, agree, disagree or fully disagree.

4a. supplier of raw materials4b. supplier of equipment4c. producer of raw materials4d. producer of equipment4e. trade organisation4f. chamber of commerce4g. consultancy firm4h. other firms (having the same kinds of technical problems)4i. a university or college4j. a research organisation4k. a government agency41. a non-profit innovation centre4m. a municipal licensing authority4n. customer(s)

5. And to what extent do you agree with the following statements?

Sa. When considering a new investment we limit the number of extemal advisors as much aspossible!

5b. Environmental performance of new equipment needs to be discussedwith external parties whodo not supply the equipment themselves

5c. Building up good contacts with different parties in the local community payoff when it comes toacquiring information relevant to one's company and what strategy to follow.

229

Adoption of Env;ronmentallnnovat;ons

ASK Q10 -Q15B FOR COMPANIES IN OFFSET PRINTING ONLY (Q1=1)

10. We want to ask some questions about the usage of products for photographic processes.As regards the photograhic process, do you use films requiring low rates of chemicals(so-called low chemical replenisher films , LCRF)?

1. yes2. no

10a. Do you use diazo plates?

1. yes -> Q10b2. no -> Q11

10b. Do you use plates which can be developed solely by means of water?

1. yes2 . no

11. Do you have a 'closed' system for the development of your plates?

1. yes2. no

12. Do you apply computer-to-plate technology (CTP)?

1. yes2. no

13. Do you buy inks with low levels of heavy metals as much as you can?

1. yes2. no

14. Do you use inks with vegetable oils?

1. yes2. no

15a. Do you use vegetable cleaning agents r-;CAs) when cleaning rollers and plates?

1. yes -> NEXT SECTION2. no -> Q15b

15b. Have you ever give vegetable cleaning agents r-;CAs) a try in your firm?

1. yes2. no

230

Quasffonnaira

ASK Q20- Q258 FOR COMPANIES IN ELECTROPLATING ONLY(Q1=2)

20a. We want to know how your firm degreases the metal parts to be eletroplated. Do you applydegreasing by vapour?

1. yes -> 020b2. no -> 021

20b. Do you use water-based agents?

1. yes2. no

20c. Do you apply degreasing by immersion in boiling alkaline solutions?

1. yes2. no

20d. Do you use closed systems in the process of degreasing?

1. yes2. no

21. As regards the extention of the life of your degreasing bath, do you apply slimming of free oilfloat ing at the surface of the liquid?

1. yes2. no

22. Do you remove emulgated oil by membrane filters or eletrocoalescence?

1. yes2. no

23a. Do you have taken steps to prevent drag?

1. yes -> Q23a2. no -> 024a

23b. Do you prevent drag by dripping and tapping off the metal parts?

1. yes2. no

23c. Do you prevent drag by using an air knife?

1. yes2. no

23d. Do you prevent drag by a sleeve wiping off redundant liquid?

1. yes2. no

~ ...,,-~ 231

Adoptionof EnvironmentalInnovations

23e. Do you prevent drag by addingchemicalswhich lowersurfacetension (for fast drying)?

1. yes2. no

ASK Q24a and Q24b if Q20c=1; OTHERS GO TO Q25a24a. Do you use sprayingto rinse productspulledfrom the electroplating bath?

1. yes2. no

24b. Do you have a rinsing reservoir?

1. yes2. no

25a. Do you focus on zinc and/orcopperelectroplating?

1. yes -> Q25b2. no -> NEXT SECTION

25b. Do you use alternatives for cyanide-compounds (EDNAand NTA) as complexes?

1. yes2. no

232

Questionnaire

ASK Q30 - Q40 FOR COMPANIES IN TEXTILE FINISHING ONLY (Q1=3)

30a. We want to ask some questions about the textile finishing process.Do you use rotary screen printing?

1. yes -> Q30b2. no .> Q31

30b. Have you reduced the system content of the presses to less than 2 kg dye for each run?

1. yes2. no

31. Do you (also) use foam printing?

1. yes2. no

32. Do you use transfer printing?

1. yes2. no

33a. Do you use improved reactive dyes?

1. yes -> Q342. no -> Q33b

33b. Could you use reactive dyes, technically speaking?

1. yes2. no

34. Do you have computer-aided composition of paint colours?

1. yes2. no

35a. Do you have computer-aided measurement of dye consumption?

1. yes .> Q35b2. no -> Q36

35b. Do you have colour measuring equipment and related feed-backs to the dye-application pad?

1. yes2. no

36. Do you have a computer-aided system for the Registration and reuse of paint residues?

1. yes2. no

37a. Do you have ink jet systems?

1. yes -> Q382. no -> Q37b

37b. Do you think you will an inkjet system with in two year's time?

~ 233

Adoptionof Environmental Innovations

1. yes2. no

38. Do you use vacuumequipment to reduce waterconsumption or chemical solutions in textileswebs?

1. yes2. no

39. Do you use an atomisation process for the application of small quantitiesof liquid (waterorchemicals)

1. yes2. no

40. Do you use rollersinsteadof submersion?

1. yes2. no

234

Questionnaire

ASK Q41 - Q52C FOR COMPANIES IN INDUSTRIALPAINTINGONLY (Q1=4)

41a. We would like to knowwhat technologies you use for industrialpainting.As regardsthe way degreasing of the parts to be paintedtakes place, do you applyhalogenated hydrocarbons?

1. yes -> 0422. no -> 041b

41b. Do you use ultrasonicvibrationwith sodaor soapsolution?

1. yes -> 041c2. no -> 042

41c. Do you applydegreasing by immersionin alkaline (water-based) solutions?

1. yes2. no

42. Do you use closedsystemsin the process of degreasing?

1. yes2. no

43. As regards the extentionof the life of yourdegreasing bath, do you applyskimming of polluting materialsat the surface of the liquid?

1. yes2. no

44. Do you remove polluting materialsby membranefilters?

1. yes2. no

45a. Do you have taken stepsto preventdrag?

1. yes -> 045b2. no -> 046

45b. Do you preventdrag by drippingandtapping off the metal parts?

1. yes2. no

45c. Do you preventdrag, by adding chemicalswhich lowersurfacetension?

1. yes2. no

46. Do you use rinsing reservoirsand/or1 or 2 step cascade baths?

1. yes2. no

~ ....0 235

Adopffon 01Environmental Innovations

47. Do you use cascade baths with more than 2 steps?

1. yes2. no

48. Do you have concentrations of organic solvent of less than 10 percent?

1. yes2. no

49a. Do you have a muffling process?

1. yes2. no

-> Q49b-> Q50

49b. Do you use an afterbumer for the removal of waste gases?

1. yes -> Q49c2. no -> Q50

49c Do you have an afterbumer with heat exchange?

1 . yes2. no

50a. Do you practice cathaphoresis?

1. yes -> 050b2. no -> 051a

50b. Do you have filtering of rinsing water and feed-back of paint to main bath?

1. yes2. no

51a. Do you practice wet-spraying?

1. yes2. no

-> Q51b-> Q52a

51b. Do you apply water screens?

1. yes2. no

51c. Do you filter the water and recover the paint for reuse?

1. yes2. no

52a. Do you practice powder coating?

236

1. yes2. no

-> Q52b-> Q60

52b. Do you use a cyclone system and have continuous feed-back of powder?

1. yes -> 0602. no -> OS2c

52c. Do you have a filter system at the exhaust of the cabin?

1. yes2. no

QuasI nnaira

237

AdopUon of Environmenl8//nnovations

ALL RESPONDENTS

Finally, I wouldlike to asksomequestionsfor statistical purposes.

60. Canyoutell me howmanyemployees areworking at yourcompany?

............. employees

61. Andwhatis yourjob title?1. General director2. Technicaldirector

62. Notegender withoutasking

1. male2. female

Thesewereall my questions. Thank youverymuchfor yourcooperation to ourstudy.

238

Annex IV: Technical Survey

239

Contents

Preface andacknowledgements 247

1 General Introduction 249

1.1 Introduction 249

1.2 The contents of the sector reports 249

1.3 Technological trajectories 250

1.4 Actors and factors 252

1.5 Literature 253

2 Environmental innovations in offsetprinting 255

2.1 Basic processes 255

2.1.1 Printing processes 255

2.1.2 Offset: pre-press stages 255

2.1.3 Offset: printing 256

2.2 Technological developments 258

2.2.1 Developments in pre-press technology 258

2.2.2 Developments in printing technology 261

2.3 Environmental issues 262


2.4.1 Photographic process 264

2.4.2 Printing plate chemistry 265

2.4.3 Printing inks 266

2.4.4 Damping solution 269

2.4.5 Cleaning agents 270

2.5 Technology status 271

2.5.1 Photographic process 271

2.5.2 Printing plate chemistry 271

2.5.3 Printing inks 271

2.5.4 Damping solut ion 273

2.5.5 Cleaning agents 273


2.7 Literature 275

2.8 Appendix: Experts and organisations consu lted 275

3 Environmental innovations in electroplating 277


3.1.1 Introduction 277

3.1.2 Pre-treatment 278

3.1.3 Main process 278

3.1.4 Finishing 279

3.1.5 Producttransport 279

3.2 Technological development 279

3.2.1 Chemical. 279

3.2.2 Newcoating materials 279

3.2.3 Processautomation 280



3.4.1 Degreasing 281

3.4.2 Reduction of rinsing water 283

3.4.3 Cyanidereduction 285

3.4.4 Passivationof zinc 285

3.4.5 Electroplatingof plastics 286




3.5.3 Cyanidereduction 289

3.5.4 Passivationof zinc 289

3.5.5 Electroplating of plastics 289


3.7 Literature 291

3.8 Appendix A.1 Expertsand organisationsconsulted 292

3.9 Appendix A.2 Technologies for purification of wastewater 292

4 Environmental innovations in textile finishing 295

4.1 Basic processes 2954.1.1 Pre-treatment. 295

4.1.2 Dyeing 296

4.1.3 Printing 298

4.1.4 Finishing 298

4.2 Technological development. 299

4.2.1 Currenttechnologies 299

4.2.2 New technologies 302

4.2.3 Technologies under development 303


4.4 Technological trajectories and technology status 305

4.4.1 Reduction of dye consumption 305

4.4.2 Reduction of waterconsumption 309

4.4.3 Reduction of energyconsumption 3104.5 Actors & factors 311

4.6 Literature 312

4.7 Appendix: experts and organisations consulted 313

5 Environmental innovations in industrial painting 315


5.1.1 Introduction: A variety of processes 315

5.1.2 Sourcesof environmental emissions 315

5.1.3 Wet paint spraying 316

5.1.4 Cathaphoresis 317

5.1.5 Powdercoating 318

5.2 Technological developments 320





5.4.3 Reduction of organicsolvents 323

5.4.4 Reduction of chemicals in waste water 323

5.4.5 Reduction of chemicals in waste gases 324

5.4.6 Improvement of paint efficiency in cathaphoresis 324

5.4.7 Improvement of paintefficiency in wet-spraying 324

5.4.8 Improvementof paintefficiency in powdercoating 325



5.5.2 Reduction of rinsingwater 326

5.5.3 Reduction of organic solvents in cathaphoresis 327

5.5.4 Reduction of chemicals in wastewater 327

5.5.5 Reduction of chemicalsin waste gases of muffling 327

5.5.6 Improvement of paintefficiencyin cathaphoresis 328

5.5.7 Improvement of paint efficiency in wet-spraying 328

5.5.8 Improvementof paint efficiency in powdercoating 328


5.7 Literature 330

5.8 Appendix: Expertsand organisations consulted 330

Technological developments in offset printing, electroplating, textile finishing and industrial painting

Technical Survey

Preface and acknowledgements

This report is one of the first results of the research project 'Environmental Innovation and

SMEs. The Dynamics of Innovation' (ENVIS), which is part of the European Union's 'Envi

ronment and Climate' programme. The project is carried out by an international consor

tium of researchers from Denmark, Italy, the Netherlands, Portugal and the United King

dom.

One of the main objectives of the research project is to provide insight into the mecha

nisms of environmentally relevant innovation processes, with emphasis on the behaviour

of small and medium-sized enterprises. The sheer number of such enterprises within the

European Union justifies a detailed description of these innovation processes, highlighting

the opportunit ies for improved innovation policies, at national as well as international level.

The present report analyses a number of environmentally relevant technological devel

opments in four different sectors of industrial production. These developments can be

seen as successive steps in the improvement of products and processes. 'Real world'

technological systems - so-called 'basic designs' - have been described, of which certain

key-elements have been followed in their evolution to economically and environmentally

accepted products. For each of the sectors selected - offset printing, electroplat ing, textile

finishing and industrial painting - several of these 'technological trajector ies' are pre

sented.

Apart from the description of innovative technological developments - which should be

considered as the main contribution of this report to the ENVIS project - the report gives

estimates of the degree of diffusion of all innovations mentioned. In this way, it provides

the opportunity to focus on 'best practices' of today and to study these in greater detail in

selected cases. The diffusion characteristics apply primarily to the Dutch situation, be

cause verification of the data was not feasible in all cases. It can be safely assumed,

however, that they are valid for most of the other countries involved in the project.

The description of technological innovations in this report is characterised by a consider

able amount of detail. This is inherent in the method applied, which is based on concepts

by Dosi and others, and empirical studies by Hagedoorn c.s. The detailed descriptions

allow us to create a link between the theory of the innovation and diffusion process on the

one hand, and practice as encountered in enterprises on the other.

This study offers an overview of technological developments in certain industrial sectors ,

over some period of time, with emphasis on environmental innovations in products and

production processes. The information for this kind of description is not readily available in

manuals or textbooks. Therefore, our primary sources are experts from several public or

industrial laboratories, and technical staff from research or employers' organisations of the

sectors involved. They all have tried to explain the technological processes in 'simple' lan

guage. We are grateful for their contribution; their names are included in the separate

247


sections of the report. In the initial collection of the raw data and first tracing of technolog i

cal trajectories the efforts of Bert Janson (as a trainee from the Technical University of

Eindhoven) were very valuable . Comments and suggestions for improvements came also

from the international project team during a fruitful workshop in Roskilde, Denmark. Spe

cial mention should be made of Dr. Rene van Berkel (IVAM - University of Amsterdam) for

his valuab le remarks and additions to technolog ical trajectories in the draft stage of the

report .

Paul Kalff

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Technical Survey

1 General Introduction

1.1 Introduction

This report gives background information on the technological developments within four

selected industrial sectors, with special reference to those developments which have sig

nificantenvironmental impacts.

The industrial sectorsselected are:

• offsetprinting

• electroplating

• textile finishing• industrial painting.

The NACEcodesof the sectors are given in table 1.1 .

table 1.1 sectors and NACE codes

sector NACE Rev. 1 NACE 1970

offset printing 22.22 473.10; 437.21-437.23

electroplating 28.51 313.50

textile finishing 17.30 437.10-437.40

industrial painting 28.51 313.50

activity

printing excl. newspapers

treatment and coating of metals : plating

textile finishing

treatment and coating of metals : lacquering

The above NACE clusters contain the activities targeted for further field work, but may

involve largergroups.

In the following sections, first a description will be given of the formatof each of the tech

nological sector reports (chapters 2 to 5). Then two other issues will be dealt with: a) the

conceptof 'technological trajectory', used for the description of specific technological de

velopments, and b) sometheoretical notions related to actorsand factors involved in environmental innovations.

1.2 The contents of the sector reports

The chapters 2 to 5 are devoted to the technological developments in the sectors chosen.Theyare set up as follows:

a. General description of the basic production processes. This description should give afeel for the relative importance of the successive steps in the technological development.

b. Description of general technological developments, relating to environmental as well

as other issues. For this overview in some cases a period of about40 years, from thefifties up to the present, has been covered.

c. Overview of environmental problems of the processes involved, solutions and relatedissues.

249


d. Description of technological trajectories relating to environmental issues. Each trajec

tory presents successive technological changes for a certain part of the process.

e. For each trajectory the available technologies are classified as obsolete, average

practice, best practice or representing the technological frontier. In this way, an overall

picture of the sector is given: what parts are advanced and what transformations can

be expected to take place? This picture may vary somewhat from country to country.

For the sectors chosen, it is assumed that the situation in the Netherlands does not

differ essentially from the other countries.

For each trajectory, the actors and factors involved in the various innovation steps are

indicated.

1.3 Technological trajectories

For a number of years, the concept of 'technological trajectory' has been known in the

theory of technological developments . Hagedoorn et al. (1988) have applied the concept

in a description of technological developments regarding process control equipment. Their

approach has largely been followed in this report.

Technological developments within most sectors are based on so-called technological

paradigms. These are relatively ordered paths of technological development shaped by

the technological properties, the problem-solving heuristics and the cumulative expertise

involved (Dosi and Orsenigo, 1988). Technological paradigms define the technological

opportunities for further innovations and some basic procedures on how to exploit them

(Dosi, 1988). An example is the development of computer chips: the present paradigm

prescribes certain semiconductor materials, micro-electronic multi-transistor design rules,

and electricity as the driving force behind the system. An other paradigm for the functions

of the computer chip would evolve if visible light instead of electricity would be used. This

would make an enormous difference in design rules, selection of materials, etc.

Within a given technological paradigm certain basic designs can be found. These are

concrete technological systems or products which largely remain unchanged over ex

tended periods of time, e.g. the personal computer of the past 15 or 20 years. Its basic

design has not changed, although capacities, speeds, functions and the like have en

hanced tremendously . Another basic design within the realm of computers is the main

frame computer, which is quite difterent from the personal computer.

Technological developments might be defined at the level of paradigms and basic de

signs. However, for the purpose of this report, actual developments can be better demon

strated by selecting certain technological key-elements within a basic design, and by de

scribing technical improvements around them. Such improvements that successively

emerge represent a technological trajectory . A technological trajectory is the activity of

technological development along the economic and technological trade-ofts defined by a

basic design . For instance, if we stay with the example of the personal computer as a ba-

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Technical Survey

sic design, the successive generations of micro-processors (types 086, 286, 386, 486,

Pentium, ...) form a technological trajectory, which lends itself to further qualitative and

quantitative description (characteristics, numbers sold, etc.). The monitor screen (cathode

ray tube, LCD-panel, .. .) and operating software systems (MS-DOS, Windows , ...) are

other key-elements having specific technological trajectories.

This report focuses on the description of technological trajectories. Within each techno

logical trajectory, four generations of technologies are distinguished. At a certain moment

in time several generations may exist next to each other. According to their relative fre

quency distribution, the generations of technologies are characterised as 'obsolete' , 'aver

age practice' , 'best practice' and 'technological frontier'.

In the present study we will use the following definitions:

Obsolete:

• The technology is declining and is used by no more than 20% of the SMEs in the sec-

tor.

Average practice:

• The technology is used by 80% or more of the SMEs in the sector.

Best practice:

• The technology is spreading, but used by no more than 20% of the SMEs in the sector.

Technological frontier:

• The technology is used by only a small number of the SMEs in the sector on an ex

perimental basis, or is being developed by research institutes or parties such as sup

pliers.

For instance, the types 086 and 286 micro-processor can be said to be obsolete , 386 and

486 are average practice, Pentium is best practice, whereas the next generation - P6

can be said to be at the technological frontier, i.e. in the laboratory stage. It should be

noted that for most key-elements several technological trajectories may exist simultane

ously.

For each of the sectors selected the technological trajectories are defined with the aid of

the above categories.

The following should be borne in mind. Since technological trajectories are defined here

for products and processes within a given sector, very little information will be presented

about new products - substituting existing products - originating from other (new) sectors.

For instance, newer developments in corrosion protection of metal products involve a

combination of electroplating and paint coating (hybrid coatings) . This kind of innovation is

not considered as part of the electroplat ing sector, therefore, it has not been included as

one of the technological trajectories. This limitation results from the sector-oriented objec

tives of the ENVIS project to which this report belongs. In other cases, trajector ies cross

ing various sectors are conceivable , for instance when studying 'information technologies'

or 'cleaning technologies' .

251


1.4 Actorsand factors

Environmental innovations by SMEs in the sectors chosen may have their technological

origins in other sectors and may be stimulated and supported by different parties. TheENVIS project aims as a whole at identifying the actors and factors responsible for the

innovation processes involved. Therefore, all stages of the research are to contribute to

this assignment. Although this reportprimilary definestechnologies ratherthan actorsandfactors, it can make a tentative contribution to clearing up the latter. For that matter, the

next chapters also refer to this issue. Some general remarks on actors and factors can be

based on Vermeulen et al. (1994) .

Theseauthors definepolicy options for environmental chain management. Although chain

management is not the main issue of the present project, it will be clear that environ

mental innovations in mostcaseswill havechain effectsandlor will be the resultof devel

opments and requirements brought forward somewhere in the production chain involved.

Apart from material aspects (sustainable energy sources, closed production cycles), Vermeulen et al. describe environmental chain management as a social process where the

behaviour of individual companies is determined by three factors, i.e. motivation, knowl

edge and power. Environmental innovations within a production chain require certain de

greesof motivation, knowledge and powerof the first-moving companies.

Majormotives for environmental innovations are:

• responses to (anticipated) environmental regulations

• cost reduction• improvement of the image of the company or the product

• demands fromclients, the market• environmental innovations as partof a company strategy.

The power to initiate environmental innovations is largely dependent on a company's position in the production chain. In this respect it might be useful to see what positions canbe distinguished in client-supplier relations. Vermeulen et al. mention four possibilities:• Market suppliers - i.e. at the lowerend of the client-supplier chain -: these companies

supply relatively simple commodities to an anonymous market. Innovation strategies

are induced by regulations or by general trendsin marketdemand.

• Jobbers or sub-contractors: produce relatively simple products on full specification.

They followthe environmental demands of theirclients.

• Preferred suppliers: these companies have a more intensive relation with their clients,providing morepossibilities for concerted action.

• Co-makers: integrate a numberof functions with their clients, and are often empow-

ered to initiate changes in productspecifications and production processes.

The power of companies producing for the consumer market - at the 'higher' end of the

client-supplier chain - is determined by factorssuchas size, marketshare, priceelasticity,understanding of consumer tastes.

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Technical Survey

Apart from the company itself , there are other actors who may influence company deci

sions, such as government (environmental and technology policies), pressure groups

(sectoral or environmental organisations, consumers organisations) , other supply chains,

business networks (e.g. financ ial institutions) and the science and technology network.

1.5 Literature

Dosi, G. (1988) , 'The Nature of the Innovative process ', in: G. Dosi, C. Freeman , R. Nel

son, G. Silverberg and L. Soete: Technical Change and Economic Theory; Pinter Publish

ers, London and New York, pp. 221-238 .

Dosi, G., and L. Orsenigo (1988), 'Co-ordination and transformation: an overv iew of

structures, behaviours and change in evolutionary environments', in: G. Dosi.

C. Freeman , R. Nelson , G. Silverberg and L. Soete, Technical Change and Economic

Theory; Pinter Publishers, London and New York , pp. 13-37.

Hagedoorn , J., P.J. Kalff , J. Korpel (1988) , Technological development as an evolutionary

process; Elsevier, Amsterdam.

Vermeulen, w.J.v. , M.T.J . Kok, J.M. Cramer (1994) , Perspect ives on integrated chain

managemen t. Options for policy; TNO-STB , Report no. STB/94/038e (abridged English

version) , Apeldoorn.

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Technical Survey

2 Environmental innovations in offset printing

2.1 Basic processes

2.1.1 Printing processes

There are various printing technologies , which are geared to specific applications. The

most important technologies are distinguished according to the nature of the printing plate,

i.e. that part of the press which carries the actual images to be printed:

• letterpress : the printing areas of the image to be transferred to the paper (or other sub

strate) are slightly higher than the non-printing areas, i.e., each text character (or

screen dot of the image) is situated about one millimetre above the surface of the non

printing areas;

• lithography or offset: the printing areas are at the same level as the non-printing areas;

• gravure: the ink is contained in small cells (screen dots) etched into the metal printing

roller;

• f1exography: flexography is a special case of letterpress printing; the printing plate is

made of flexible material, so that rough or uneven surfaces can be printed;

• screenprint ing: the printing plate is a thin flat screen, through which the ink is pressed

onto the substrate; the non-printing parts of the screen are impermeable to ink.

Screenprinting is used for relatively large surfaces and small numbers of prints, such

as posters. Also textile may be printed according to the screen principle.

In the actual printing stage ('press' stage) the printing plate is covered with a thin layer of

ink which is transferred to the substrate, usually paper.

In the 'pre-press' stage the printing plate is produced. In most cases, text and images are

produced separately and transferred to the plate through photographic processes. To a

certain extent these processes are independent of the printing process used.

After the printing stage a number of finishing activities is required. For the production of

books these could be folding, sorting, gluing, binding, cutting, plasticizing, etc. For maga

zines or advertisers there are less finishing stages.

Compared with letterpress, offset printing makes the reproduction of images easier and

permits higher printing speeds. In the following sections the pre-press and press stages of

offset printing are considered into more detail.

2.1.2 Offset: pre-press stages

In the pre-press stages of the offset process all activities are focused on the production of

one - negative or positive - film, containing all texts and images of one or more pages of

the final product, in the right position and size. This film has the same format as the print

ing plate, and the image is transferred to the light-sensitive layer of the offset plate

255

Adoption of Environmenta//nnovations

through a process of exposure to light and subsequent development. For a complete book

or magazine several offset plates are required.

The film is composed of pieces of text (columns, pages) and photographic images. These

components are produced in two different production processes.

a. The text is produced with a specialised computer + keyboard system, supported by

text processing software. From the computer the data are transferred to a phototype

setting machine, which produces readable text on slips of photographic paper or film.

These slips can be cut and pasted onto a larger substrate, in the right format , with

open spaces for the (screened) images to be added later.

b. Photographic images are enlarged or reduced to the required size and, after screening

(the process of representing the image by means of small screen dots), pasted onto

the same substrate as the text. This 'master' paper or film is copied once more to pro

duce the final film that is to be transferred to the offset printing plate.

In modern pre-press systems the original photographic images are scanned (a process

similar to faxing) and also stored in the computer. After that, they can be electronically

integrated with the text and previewed on large computer screens in the final format.

These page make-up systems allow the make-up of, for instance, newspaper pages up to

the last minute, so as to include the latest information. Ready-made pages are transferred

to laser-based exposure machines ('printers'), where the visible output can be produced

either on photographic film or paper, or directly to the offset plate. In the latter case, the

trajectory from computer to plate is very short and does no longer involve any photo

graphic processing.

The offset (or lithographic) printing plate is an aluminium plate covered with a Iight

sensitive layer. After the exposure the lithographic plate is treated chemically (developed) ,

yielding image-carrying areas (printing areas) and non-image-carrying areas (non-printing

areas) on the plate.

2.1.3 Offset: printing

Figures 2.1 and 2.2 show the offset printing principle. Due to the surface characteristics of

the plate, the image-carrying areas are ink-receptive, whereas the non-image areas repel

ink. In the actual printing stage, a uniform layer of printing ink is applied to the plate by

means of rollers, the ink will attach to the imaging places only, and by pressing the inked

plate onto the paper the image is transferred from plate to paper.

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Technical Survey

figure 2.1 the offset principle

/ damping water

&-

figure 2.2 sheet-fed and rotary printing

sheet feed printing

rotary printing

The offset printing process has two important additional features:

a. During each printing cycle the printing plate is covered with a thin layer of water

('damping' water) more or less at the same moment of application of the ink to the

plate. This plate-damping feature takes care of a well-defined separation between

printing and non-printing areas.

# "..._~ 257


b. Between printing plate and paper there is an extra rubber roller (the 'blanket') where

the image to be printed is transferred to. This is the actual 'offset' feature, which takes

care of the surface irregularities of the paper and protects the printing plate against

early abrasion. The intermediate rubber roller allows the use of lower quality (rougher)

paper without lowering print quality to unacceptable levels.

In case of colour printing, it should be noted that for most purposes acceptable colour

prints can be made by printing three or four different images exactly on top of each other,

with different inks: cyan + magenta + yellow + black, if necessary. The printing plates for

these colours are different, of course, so for one four-colour print the total process, from

original colour picture scan to print, has to be completed four times; see figure 2.3.

figure 2.3 sheet-fed four-colour offset press

2.2 Technological developments

2.2.1 Developments in pre-press technology

Phototypesetting

The most important developments during the past decades in pre-press technologies are

all associated with the introduction of micro-electronic systems. Text processing and im

age processing have gone through revolutionary changes that made an impact on all

kinds of enterprises, small and large, in all branches of the printing industry.

It all started with the introduction of computer systems for the processing of text, mainly in

newspaper environments, during the sixties. The pure mechanical composition - by hand

of texts with typefaces in lead was extended in those years by control mechanisms de

rived from the computer industry: punched paper tapes which contained all typographical

258

Technical Swvey

instructions for the typesetting machine. These tapes were prepared by the editor, with a

computer and text processing software.

The second step came in the seventies when t he lead typesetting machine was replaced

by a phototypesetting machine, which produced text columns by flashing individual char

acters onto photographical film or paper. Dirty and heavy lead was replaced by slops of

paper or film, ready for further reprographic processing. These phototypesetting machines

diffused at high speed through all the industry, starting with the larger enterprises, but

gradually entering also the smallest printing shops. Specialised typesetting shops could

afford large, complex machines for a wide range of text applications. In the beginning, the

producers of the new machines could be found outside the original typesetting machine

supplier section, but later it appeared that the core competence was typographical knowl

edge, so that the original suppliers regained their market share after adopting the new

technology .

Image scanners

For the electronic processing of images the basic technologies have been available for

many years , but in the beginning the quality and speed of the light-sensitive elements and

control electronics did not compare to traditional silver reprographic processes. Espe

cially, as regards the processing of colour pictures, there was a need for higher process

ing speeds and more colour correction possibilities. Developments in solid state sensors

during the sixties finally led to the introduction of electronic image scanning devices, sup

plied by specialised companies, independent from the traditional suppliers such as Kodak

and Du Pont. For correction purposes (size, colour, contrast , etc.) these scanners were

linked to computers , whereas the output was recorded on photographic film. With the in

troduction of the scanner many intermediate reprographic steps could be avoided, but due

to high investment levels (including training of personnel) the diffusion of this technology

was much slower than that of the phototypesetting machine.

Page make-up

It did not take long before it was recognised that the phototypesetting machine and the

image scanner had one important element in common: the computer or computerlike

system dealing with data in digital format. The combination of the two technologies led to

the development of computerised page make-up systems, i.e. computers + software +relatively large screens for the handling of complete pages of newspapers , magazines,

etc. Especially in the newspaper environment these systems were introduced during the

eighties, because speed of processing the latest news is crucial for the newspaper pub

lisher in competition with television.

It will be clear that the shift from lead typesetting and silver-based reprography to elec

tronic systems is an on-going process that greatly affects the printing and publishing busi

ness. Larger companies will be more advanced in this respect than smaller ones, but

259


small enterprises new to the market may start with fully state-of-the-art technology. The

new pre-press technologies tend to make offsetprinting the preferred printing technology.

Speed of processing and printing, cost of equipment and materials, choice of large and

small scale production, all criteria point to offset as the most appropriate technology for

normal newspaper and magazine production in all sizes except the largest ones. In line

with these considerations, new technologies have emerged, linking page make-up sys

tems with offset plate production.

Digital data from computer to offset plate

For the preparation of an offset printing plate, traditionally, a photographic film is used, but

since the introduction of the computer-controlled laser as an instrument for 'writing with

light' the use of film has challenged. During the first half of the eighties the computer-to

plate technology was developed. Complete (sets of) pages can be produced now without

any reprographic activity. Computer-to-plate (CTP) has shown to be feasible, but up till

now it has been applied to a limited extent only, mainly in pilot projects. Further develop

ments focused (and focus) on the production of more stable, reliable systems, also for the

lower end of the market. With CTP, printers and publishers are in a position 'to enter the

digital era' with all advantages of high speed and worldwide information processing, and to

distribute this information on a multi-media basis.

The input-side is a different story, where the printer's or publisher's position seems less

favourable .

Desk top publishing

Systems for 'desktop publishing' (DTP) appeared on the market in the second half of the

eighties. They consist of desktop PC's and text processing software, supplemented by, if

required, a small laser printer. These systems allow text processing and page make-up for

professional and non-professional authors. The output of the system can be a print on

paper, ready for photocopying, or a floppy disk that is processed further by the print shop

or publisher . The data may be transferred also by telecommunication to the printer or pub

lisher. This technology leads to a shift in pre-press work from the printshop to the client,

including correction work, etc.

Printing and pre-press work tend to become fully separated in time and place. Writing!

editing may be done anywhere in the world, printed matter can be produced in relatively

small batches at the actual place of distribution.

Up till now, all electronic and other developments tend to lead to a considerable reduction

in the number of steps in the pre-press stages of print production. This implies a corre

sponding reduction of environmental effects, especially as far as lead typesetting and re

prographical activities are concerned. It should be noted however, that not all print shops

can afford these modern systems. Therefore , the actually applied technologies will show a

260

Technical Survey

considerably variety . The same goes for the press stages of the printing process, although

developments there are not as spectacular as in the pre-press stages.

2.2.2 Developments in printing technology

Developments in offset printing technology mainly relate to general improvements of the

traditional printing process. The wide-spread diffusion of the offset process has led to a

variety of techniques, materials and working methods. However, there is no change in

'technological paradigm', like observed in the pre-press area. Offset printing always in

volves the application of ink. To that end, the printer uses printing plates, carefully bal

ances the water-to-ink ratio, and takes care of the right ink densities, correct drying of the

ink, exact fitting of the four images when printing in colour, and timely cleaning of the

system. The most relevant (incremental) innovations in offset printing are indicated below.

Press type variety

Offset presses have become available in all kinds of sizes and speeds, both for sheet

printing and rotary printing. Large newspaper offset presses have replaced the older let

terpress machines. Many printing units combine multi-colour printings and integration of

several paper webs into one system. The larger machines are tailor-made for the client.

For office use there are simple, 'one-button' systems where plate preparation and printing

can be done by non-professionals .

Press automation

Ink and water supplies are fully controlled by electronic systems. Sensors and actuators

handle paper transport and web tension. Changing over from one roll of paper to a new

one is fully automated , it does no longer require stopping the press. Even cleaning of the

system can be performed under strictly controlled conditions.

Chemistry of inks and fountain solution

Composition and qualities of printing inks and damping water change over time in order to

comply with environmental demands. Apart from that, each supplier of these ingredients

uses his own specifications, claiming improved performance. Especially ink drying

mechanisms may vary from one application to the other. This will be discussed in more

detail later.

And the future?

There is one threat which might affect not only the offset system, but the total printing in

dustry. It is the colour copying technology. Colour copying technologies are finding their

way into the printing industry. It is expected that in the near future part of the offset print

ing will be replaced by this new technology.

261


The first presses on the basis of copier technology were introduced about two years ago.

Printing speeds and numbers of copies per original are still comparatively low, but devel

opments go on. Also copy quality does not yet compare to quality in traditional printing.

Special problems, for instance, occur with printing of packaging material, where copier

technology causes 'cracks' in the printing surface during folding.

2.3 Environmental issues

A brief overview of the major environmental effects in offset printing helps to generate

valuable insight into where future environmental policies are likely to focus upon.

Photographic processes

In the pre-press stages of the offset process large quantities of photographic film (or pa

per) are used. Text from phototypesetting machines needs development and fixing; origi

nal pictures (prints or slides) need sizing and reproduction on special films for screening

purposes, colour extraction, etc. All processes of development and fixing are based on the

silver-halide process, which means that silver and many chemical compounds are in

volved. Several technical and organisational measures can be taken to reduce the

amounts of silver involved. These will be discussed below (section 2.4.1). However, from

an environmental point of view, the most important development is the computer-to -plate

technology , which makes chemical processing of film and offset plates completely obso

lete.

Since 1990 Dutch legislation prohibits the use of cadmium in certain types of reprographic

films.

Treatment of offset plates

The treatment of offset printing plates after exposure to light (through the 'master' film)

also involves development with chemicals. The CTP technology avoids this treatment.

In earlier days offset plates required some kind of 'fixing' after development. The fixing

solution contains acids, various kinds of alcohol and, after use, silver-compounds . This

practice can be considered as obsolete now; sometimes fixing of offset plates can still be

found in small printing shops.

Used offset plates can be recycled.

Printing inks

Offset printing inks contain pigments, binders (to fix the pigments to the paper) and in

some cases drying agents (to speed up the drying process). All compounds in printing

inks provide risks for health and safety. Although in normal work there is little contact be

tween skin and ink, contact over prolonged periods may cause irritation or allergies. Some

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Technical Survey

pigments and traces of additives (e.g. PCAs) have carcinogenic properties. Leakage or

improper treatment of inks may cause soil pollution.

The use of heavy metals in pigments gradually decreases, although (at least in the Neth

erlands) there is no formal legislation preventing their use. An exception to this refers to

cadmium, which is not allowed to be used in both pigments and reprographic films. In

section 2.4.3 more details concerning printing inks will be given.

Damping solution

For a number of reasons, additives are used in the damping water, such as anorganic

acids (to control the hydrogen ion concentrat ion), organic substances (against formation

of algae) and heavy metal (cobalt, manganese) containing compounds. From an environ

mental point of view, one of these additives, isopropyl alcohol (IPA), deserves more atten

tion. IPA is said to improve printing quality, to make press settings less critical, and to be

effective in keeping the roller system cleaner and cooler than without. Consequences for

the environment are discussed in section 2.4.4.

Cleaning agents

Cleaning substances with solvents such as turpentine, toluene, chlorinated compounds

and alcohols, are widely used in the offset printing shop. Ink duct, printing rollers, plate

and blanket roller have to be cleaned from traces of ink at reqular intervals to keep up

printing quality. Cleaning towels get drenched by ink and solvents, and the vapours pro

vide health risks. In section 2.4.5 attention will be paid to the technical trajectories in rela

tion with these substances .


In this chapter innovation processes in offset printing will be considered into greater detail.

This will be done by using the concepts introduced in chapter 1 of this report. A selection

of technological trajector ies will be made to describe actual innovation processes. It

should be noted, however, that reduction of problems with health and environment,

caused by materials and working methods in offset printing, may also be attained by 'good

housekeeping'. Examples of good housekeeping are:

• prevention of leakage of chemicals by installation of special trays

• recycling of cleaning towels

• recycling of ink remainders by mixing in black ink

• use of the 'ink-gun', this is a carton box from which the ink is transferred into the ink

duct by a pistol-like mechanism, resulting in very little waste.

These are examples of very modest innovations, but normally they are not recognised as

such.

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Adoptionof EnvironmentalInnovations

The concept of technological trajectory was introduced in chapter 1 of this report. It was

defined as a series of technical improvements in succeeding generations of a key-element

of a basic design. A basic design is a concrete technological system which remains es

sentially unchanged over an extended period of time.

As far as offset printing is concerned, it might be stated that since its invention two basic

designs can be distinguished. The first design - which is obsolete now - involves a spe

cially prepared flat stone as the printing form (from which the term lithography is derived),

the second is characterised by the metal printing plate and the intermediate blanket cylin

der. This is the present basic design. Key-elements in this design are the printing plate,

the blanket, printing ink, damping water, control systems, cleaning agents, etc.

If offset printing would be substituted by colour copier technologies, it would be reason

able to consider this as a change of technological paradigm.

In the following sections the most relevant environment-related technological trajectories

in offset printing are described.

2.4.1 Photographic process

The normal photographic pre-press reprographic systems are not fully specific to the off

set process, they can also be found - with modifications - in other pre-press printing tech

nologies. The photographic process has nevertheless been chosen for a technological

trajectory because of its importance in the overall offset technology.

The trajectory is:

1. traditional photographic processes

2. recovery of silver (in-house or out-sourced)

3. low chemical replenisher films

4. silver-free films.

The technologies can be indicated as follows.

1. The traditional production of intermediate pieces of film and photographic paper, as

well as the final 'master film' from which the offset plate is produced, involves the sil

ver-halide process, Le. the process of development and fiXing of the latent images.

Used developing and fixing liquids contain anorganic compounds (bromides, sulphites,

sulphates , thiosulphates, ammonia), organic compounds (such as benzene

derivatives) and complexes (anorganic or organic compounds) with silver. These sub

stances are part of the waste water of the printing shop and need careful recollection

and removal. Under normal conditions the suppliers of the photochemicals take care of

this.

2. One way of dealing with the silver in the fixing liquid is 'in-line' recovery, by means of

electrolysis . The silver is recollected and can be sold to specialised firms (e.g. for the

production of ornaments), whereas the fixing liquid can be used for more prolonged

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Technical Survey

periods of time. In the Netherlands, companies using more than 700 Iitres of fixing liq

uid per year are obliged to recover photographic silver in this way.

3. Apart from the recovery technique, reprography suppliers have developed new films

and corresponding chemicals that require much smaller amounts of chemicals than the

traditional process. The 'replenishments' of chemicals in developing machines occurs

at rates up to 60% lower than normal. The adoption of these 'low chemical replenisher

films' is still low, however.

4. A relatively new technology without any silver in the film has recently been developed

by Kodak in co-operation with the Japanese firm Screen. This technology is in use by a

few European companies on an experimental basis. In special high-powered laser ex

posure machines the image is 'burnt' into the film. No chemicals are required. The only

waste comes from dust particles produced during exposure; this dust can be captured

by filters. A disadvantage of this process is its present speed, which is lower than that

of the conventional photographic process.

2.4.2 Printing plate chemistry

Offset printing plates are available in many types for various applications. An important

criterion for the selection of an offset plate type is order size: large quantities require more

robust plates than small ones. In this respect three groups of offset plates can be distin

guished:

• plates for limited editions, such as plates for in-house printing shops: the chemistry of

the plate is adapted to simple and quick processing: diffusion-transfer plates, electro

static plates and silver-based polymeric plates;

• plates for the usual commercial printed matter: here only two types of plates are of im

portance: the photopolymer plate and the diazo plate;

• plates for large qualities, such as needed for national newspapers and rnaqazines:

special 'tri-metal' plates, with chromium-based printing surface reinforcement.

To define a technological trajectory , the second class of plates has been taken as a refer

ence. The developments can be described as follows:

1 photopolymer plates

2a diazo plates, water/soap development + fixing

2b diazo plates, water/soap development only

2c diazo plates, water-only development

3 silver-halide plates

4 closed development systems.

These technologies can be summarised as follows.

Diazo plates are used most often in the offset printing shop. The photopolymer plate

gradually becomes obsolete; it is replaced by the diazo plate. Photopolymer plates still

265


have some special applications, such as for use with ultra-violet-drying inks. At this mo

ment diazo plates are estimated to have a share of 98% of the European market.

Photopolymer plates are developed chemically by means of various organic substances .

In order of improving technology (as far as the environment is concerned) the diazo plates

2a, 2b and 2c appeared on the market. Modern diazo plates can be developed by tap

water only. A distinction can be made between 'positive' plates and 'negatives' plates (to

be produced with positive or negative films, respectively) . Positive diazo plates have been

available for some 25 years now, negative plates for about 12 years; the latter are consid

ered to be less polluting during development.

A general trend on the hardware-side of development systems, for small and medium

sized as well as large printing shops, is the use of semi-automated (cuvettes) or auto

mated development machines, replacing development by hand. The change-over to ma

chine-development implies a reduction of health and safety risks.

Silver-halide plates are used in CTP systems, so their application is relatively modest.

A more recent development is the use of 'closed' development systems for diazo and sil

ver-halide plates. These systems are primarily designed to reduce water consumpt ion,

especially in those countries where the costs of water have increased sharply in recent

years. Closed systems take care of water purification; the suppliers anticipate environ

mental regulation by the authorities.

2.4.3 Printing inks

The composition of offset printing inks may vary. It is inter alia contingent on purpose,

printing volume, colours, type of press and drying systems, but in general the following

substances will be present: pigments (15-30%), binding agents (30-35%), mineral and

drying oils (ca. 30%) and auxiliary agents (ca. 5%).

Pigments are insoluble anorganic or organic substances with high coating power, in many

cases consisting of compounds containing metals like calcium, barium, magnesium, cop

per, nickel, cobalt, zinc, iron, aluminium and titanium. Black ink contains carbon. Metal

compounds and the organic part of pigments may involve health and safety hazards.

Binders are mixtures of various types of resins, Le. organic compounds. They take care of

the binding of the pigment particles to each other and to the paper.

Mineral and drying oils are carriers for the pigments and binders. They allow the transfer

of the pigments from the press to the paper, and play an important part in the drying proc

ess. There are two kinds of drying: physical drying and chemical drying. Physical drying

means mineral oils are absorbed by the paper. Drying oils, such as linseed oil, react with

oxygen in the air: this is the chemical drying.

Auxiliary compounds , such as drying catalysts, may contain metals: cobalt, manganese

and others.

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Technical Survey

As far as technological trajectories for environmental innovations related to printing inks

are concerned , it seems appropriate to distinguish three lines:

• pigments: the gradual change-over to pigments containing less heavy metals

• oils: the trend towards vegetable oils

• drying systems .

For each of these trajectories a short description will be given.

Pigments

For many years the large number of metal-containing pigments in printing inks have been

subject to health and safety studies. Although these studies do not unambiguously dem

onstrate serious problems with all kinds of pigment, there is a general tendency to shift

from heavy-metal-conta ining materials towards lighter metals or no metals at all. An obvi

ous example of this in the Netherlands is the legal prohibition (the only one of this kind) of

cadmium in all pigments (less than 50 mg/kg, since 1990.

At present, there are alternatives to all heavy-metal-containing pigments. Even for the

copper-containing pigments ftalocyanine and fanal there are alternatives , albeit of lower

quality. In practice, however, various heavy-metal pigments are still being used because

of special quality requirements by clients. Unless strict regulations are in place, product

quality demands (covering power, colour intensity, durability, etc.) will have priority over

environmental demands.

The technological trajectory focusing on pigments is relatively hard to define. It can be

seen as a two-step trajectory :

1. absence of any awareness (towards suppliers or clients) of the hazards related to the

presence of heavy metals in ink pigments

2. efforts to reduce heavy-metal content in pigments (or other ink components).

Oils

The use of oils in printing inks was explained earlier. Traditionally, mineral oils are used,

also as a solvent for the various kinds of resin (binding agents) in the ink. The oil content

in inks for rotary offset printing is about 35%; this high percentage creates environmental

problems (see under 'Drying systems'). Mineral oil content in sheet fed offset ink is low

and poses hardly any environmental problems. The present trend towards the substitution

of mineral oils by vegetable oils is supportive of the general policy to reduce volatile or

ganic compounds (VOCs). Mention is made of soy bean oil and coconut oil as substitutes

of mineral oils.

The technolog ical trajectory here is very straightforward :

1. use of inks with mineral oils

2. use of inks with vegetable oils.

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Drying systems

Drying of printing inks occurs through a number (often in combination) of basic physical

and chemical processes, a detailed description of which would go beyond the purposes of

this report. Therefore , only a description of the major technical systems will be given.

The traditional process of ink drying is based upon the absorption of oxygen from the air.

The oxygen starts the polymerisation of, for instance, the linseed oil, which then hardens

and binds the pigment particles to the paper. Higher printing speeds, in sheet-fed offset

printing and especially in rotary printing, requires higher drying speeds. By adding

(synthetic) resins to the ink, the drying process could be accelerated. Starting from this

situation we need to make a distinction between sheet-fed offset and rotary offset.

In sheet-fed offset, ink drying may occur through absorption of the liquids into the paper

followed by oxidation of the solid matter remaining on the paper. For this process special

'quick-set ' inks are prepared. Another solution is given by the so-called 'cold-set' inks.

Here the actual print is made at higher temperature - when the ink is relatively thin. After

cooling of the print the ink is more solid and dry.

The total emission of ink components in sheet-fed offset is relatively low.

More important developments are to be found in rotary offset printing. The higher drying

speeds have been obtained by feeding the paper web through oil- or gas-heated tunnels.

Here special 'heat-set' inks are used. To avoid large emissions into the open air, filters

can be connected to the drying tunnels, for recycling the oils. Also afterburners are used,

causing the emission of breakdown products and bad odours. Heat-set inks without oils,

or water-based inks, have been developed, but found up till now very limited application.

A special development for ink drying - mainly on rotary presses - is the ultra-violet drying

process. Here the printed paper is fed through an intense beam of ultra-violet radiation,

which starts a fast polymerisat ion process. There are no emissions when using these UV

inks, but the radiation may cause damage to the eye and produces ozone. Special pre

cautions are required in this respect, which makes the system relatively expensive .

For only a fraction of the costs of the UV drying system, an infra-red drying system can be

installed. Here IR radiation penetrates the ink surface, produces heat within the ink layer

and thus speeds up the drying process. This system is used in sheet-fed offset also, es

pecially in four-colour sheet printing.

For special applications electron beams can be used to speed up the drying process, just

like UV drying. This technique can be applied when thick coatings are required. It is less

suited for paper printing.

All these developments lead us to the following technological trajectory for ink drying

processes :

1. traditional drying: drying oils, synthetic resins

2. quick-set; cold-set

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Technical Survey

3. heat-set

4. infra-red drying

5. ultra-violet drying

6. electron beam drying .

It should be taken into account that heat-set drying primarily applies to rotary printing.

2.4.4 Damping solution

The water in the fountain duct of the offset press often contains additives, which may have

several functions, such as lowering the surface tension of the liquid or elimination of al

gae.

From an environmental point of view, the addition of isopropyl alcohol (IPA) to the damp

ing liquid is important. In rotary offset 10-12% IPA is added, which in 1990 resulted in 500

tonnes of emiss ions by Dutch companies. In sheet-fed offset 8-10% IPA is added, which

in 1990 amounted to an emission of 1,300 tonnes.

The real function of IPA is not fully known. It is said to improve print quality by lowering

surface tension of the damping fluid, to give easier control of press variables , to be effec

tive in cleaning and cooling of the printing plate, etc.

Environmental and health problems with IPA are well known: it has a narcotic effect on the

human nervous system, and as a volatile organic compound (VOG) it contr ibutes to smog

formation .

Substitutes for IPA are said to be available from a number of suppliers, but their quality is

lower than that of IPA; some of the substitutes are said to be more detrimental to health

and environment than IPA.

Research by press manufacturers MAN Roland and Coatec indicates that lower concen

trations of IPA are feasible when using ceramic rollers in the press, at least for the damp

ing system.

An alternat ive to IPA is dry offset. The development of special offset plates producing high

quality prints without the use of damping fluid could solve the IPA problem. The search for

dry offset took many years , but is reported to be reliable now. The plates are composed of

photopolymer and silicon layers. The drive behind dry offset is print quality, and not IPA

reduction. Dry offset also reduces the amount of press cleaning. Up till now, disadvan

tages of dry offset are:

• plates are relatively expensive , which is a problem for small printshops with many short

runs

• special links are required, which are more expens ive than normal inks

• press adaptat ions are required , inter alia cooling of certain units.

The technolog ical trajectory for the damping solution can be indicated as follows:

1. plain water

2. water with isopropyl alcohol (IPA)

269


3. ceramic damping rollers

4. dry offset.

2.4.5 Cleaning agents

Cleaning of printing rollers, printing plate and blanket is an almost continuous activity dur

ing press preparation and printing. To a large extent print quality is dependent on cleaning

with regular intervals.

Traditionally, cleaning agents are derived from petroleum and turpentine. They are vacs,

containing aromatic compounds , such as toluene, xylene and trimethylbenzene , as well

as aliphatic compounds , such as alcohols, ethers and ketones. Like IPA, they degrease

the skin, affect the human nervous system and contribute to smog formation. In the Neth

erlands sheet-fed offset produces 2,000 tonnes of vacs per year (apart from IPA); for

rotary offset this figure amounts to 250 tonnes/year.

The first attempt to improve traditional cleaning agents focused on the elimination of all

aromatic components . In the covenant between the Dutch printing industry and public

authorities (set up in 1988) this elimination was agreed to be completed before 1996.

More recently three alternatives for the former cleaning agents have appeared on the

market. These alternatives are:

• High-boiling-point hydrocarbons

In principle there are aliphatic liquids, free of aromatic compounds. Their effects on

health and environment are smaller than before, because of lower concentrat ions of

evaporated material.

• TurpenesTurpenes are obtained from citrus fruits or softwood, so from renewable resources.

They have a low volatility, but whether they can affect the human nervous system is

not known. Turpenes may cause allergies in some cases. They may also contribute to

smog formation.

• Vegetable cleaning agents (VCAs)

These are new cleaning agents, consisting of esters from fatty acids, obtained from

vegetable oils such as soy bean oil, rapeseed oil, sunflower oil, coconut oil, etc. These

biodegradable products are produced from renewable resources. They are non

poisonous and non-volatile. VCAs are the result of an EU-stimulated development

project, which was started by Danish printers. Further research into the application of

VCAs in automated press cleaning systems is required.

The technological trajectory for cleaning agents could be defined as:

1. traditional VaC-based cleaning agents with aromatic components

2. removal of aromatic components

3. new products, such as VCAs.

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Technical Survey

2.5 Technology status

This section indicates the status of the technologies described in the previous section,

according to the definitions given in chapter 1. The information is obtained from experts in

the offset industry and from suppliers.

2.5.1 Photographic process

The traditional process is relatively old, but still in use in very printing shop with pre-press

activities. Consequently , 'obsolete' technologies cannot be identified.

process obsol. avopract. best pract. technofront.

traditional +

recovery +

LCRF +

silver-free +

2.5.2 Printing plate chemistry

The most advanced development is the introduction of CTP technology. In a way, this

technology can be considered as a preparation of the transition to a new technological

paradigm, that is, the colour copier technology. Computer technology linked to high-speed

colour laser printing may yield 'mass individualisation' of printed matter, thus replacing the

present printing technology.

process

photopolymerplates

diazo + water/soap +fixing

diazo + water/soap

diazo + water

silver-halide (CTP technology)

closed development system

2.5.3 Printing inks

obsol.

+

+

avopract.

+

best pract.

+

+

technofront.

+

Printing inks - pigments

Efforts to reduce heavy metals in printing inks may range from passive to active. Buying

new, environmentally acceptable inks offered by the supplier is average practice. Refus

ing to use heavy metals containing inks, even when demanded by the client, will be con

sidered as best practice.

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Adoptionof Environmenta//nnovations


heavy-metalproblem not known +

efforts to reduce heavymetals + +

Printing inks - oils


inks wtth mineral oils +

inks with vegetableoils +

Printing inks - drying systems


traditionaldrying +

quick-set; cold-set +

heat-set +

infra-red +

ultra-violet +

electron beam +

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Technical Survey

2.5.4 Damping solution

Damping solution

process

plainwater

water + isopropyl alcohol

ceramic damping rollers

water-free offset

2.5.5 Cleaning agents

Cleaning agents

process

traditional VOCs + aromatic comp.

VOCs. no aromatic components

VCAs or other now products

obsol.

+

obsol.

avopract.

+

avopract.

+

best pract.

best pract.

+

technofront.

+

+

technofront.

+

2.6 Actors and factors

Innovations in the offset printing shop appear to be initiated most often by suppliers of

machines (presses , reprographic equipment, typesett ing equipment) and of materials (ink,

paper, photographic film and chemicals, cleaning agents). Also the suppliers of raw mate

rials playa part, for instance in the pigment industry. Innovative research and develop

ment by the printers themselves is rare (Le Blansch, 1994), especially when environ

mental innovations are involved.

Many printers are not aware of the environmental implications of the materials they use.

Selection of equipment and materials is based on economic factors, and experiments with

alternative materials are made only when reductions in costs can be obtained. It is feared

that the new materials might damage the press or affect print quality. The opinion of the

materials supplier is very important in this respect.

In the process of innovation, the printer appears to give priority to economic factors, in

particular product quality. Most clients do not express specitic wishes as to the environ

mental quality of the printed matter they order. The authorities' role in stimulating envi

ronmental innovations is limited, as they seem to be largely satisfied with end-of-pipe

measures (Le Blansch, 1994).

With respect to the technological trajectories mentioned before, a few additional indica

tions as to the actors and factors involved, are given.

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Photographic process

In the Netherlands, the removal of silver from fixing liquids is part of the convenant be

tween printers and public authorities. Printers, suppliers of reprographic materials and

new service providers (recycling of silver) are involved.

Computer-to-plate systems are clearly very important in the process of elimination of all

chemical activities in reprography and plate preparation. These systems are developed by

the equipment industry (computerised text and image processing, plate suppliers) in line

with the general change-over to complete digital processing. The larger printers and spe

cialised firms take the lead in these developments.

Printing plate chemistry

Developments are initiated by the plate suppliers, working towards simpler processes.

Systems for reduction of use of water focus on cost reduction.

Printing inks - pigments

The reduction of heavy metals in pigments is the work of the pigment industry anticipating

regulation in this respect. Printers are inclined to follow their clients when special quality

requirements are set, even if this implies the use of heavy metal pigments, so the market

for these pigments is changing only slowly.

Printing inks» oils

The change-over to vegetable oils anticipates regulation of the use of hydrocarbons .

Covenants are set up sectorally; in the Netherlands there is still no covenant with the paint

and ink industry.

Printing Inks» drying systems

The measures for reduction of solvent emission in rotary offset printing (heat-set) are

based on legislation concerning air pollution for individual enterprises (settlements) . UV

drying inks are developed on technical grounds, but they fit in the regulatory develop

ments towards hydrocarbon reduction.

Damping solution

The reduction of IPA in damping solutions takes place very slowly. There is hardly any

substitute for IPA with comparable quality characteristics . In the Netherlands the reduction

of IPA is part of the covenant between printing industry and the public authorities . Alterna

tives (ceramic rollers, dry offset) are developed by the equipment industry, without large

success , up till now.

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Technical Survey

Cleaning agents

Vegetable cleaning agents is the only example in this survey of an environmental innova

tion initiated by the printing industry.

2.7 Literature

Bilderbeek, R. (1993), Technologie en economische structuur in de grafische industrie en

uitgeverijen ; AWTfTNO-STB , Den Haag/Apeldoorn

Bloot, J. (1989), Chemische stoffen in offsetdrukkerijen; gezondheidsrisico 's en arbeids

hygienische adviezen ; Centraal Bureau voor de Grafische Bedrijven; Amstelveen

Kemp, R.P.A., AA Olsthoorn , F.H. Oosterhuis, H. Verbruggen , m.m.v. J. van Swigchem

en T. Daamen (1991), Instrumenten voor de stimulering van milieutechnologie,

Beleidsstudies Technolog ie Economie nr. 14; Ministerie van Economische Zaken, Den

Haag

Le Blansch (1994), Offset printing companies and the environments, paper presented at

the 3'dInt. Research Conf. of the Greening of Industry Network, Copenhagen, Denmark

Limburg, M. (1995), Gutenberg goes digital ; Blueprint, London

Reerink, A.M., D.R. van Veldhuisen, M.A.M. Snuverink (1989), Informatiebundel

drukkerijen; Handhaving Milieuwelten , rapport nr. 1989/3 (herziene uitgave); Ministerie

VROM, Den Haag

Schilstra, D. (ed.) (1978), Drukinkt, Instituut voor Grafische Techniek TNO, Amsterdam

2.8 Appendix: Experts and organisations consulted

N. Harderwijk

Ing. T. Mansens

P. van der Slot

A Valkenburg

Mrs. M. van de Ven

Drs. AC. Winkelaar

KVGO - Koninklijk Verbond van Grafische On

dernemingen; Amstelveen

KVGO - Koninklijk Verbond van Grafische On

dernemingen; Amstelveen

Kodak; Odijk

Du Pont Printing and Publishing BV; Soest

Chemiewinkel Universiteit van Amsterdam; Amster

dam

VWF - Vereniging van Verf- en Drukinktfabrikanten ;

Leiden

275

Technical SUlvey

3 Environmental innovations in electroplating

3.1 Basic processes

3.1.1 Introduction

Electroplating is the electrolytic deposition of a metal layer on metal products with the pur

pose of changing the original properties or size of the product's surface. The metal layers

usually serve as decoration or protection against corrosion or wear (Boer et a/. 1991;

Mortier et al., 1992).

The electroplating process consists of various separate treatments ; some of these are

repeated so as to obtain better results (Vlieger et aI. , 1996). The main process steps are:

• pre-treatment: degreasing , cleaning

• main process : electrolytic deposition of a metal layer

• finishing.

Between these treatments there are one or more rinsing stages; see figure 3.1, which is a

simplified representation of the process . In practice, for instance, there are several stages

(baths) for cleaning and degreasing. Sometimes, more than one metal layer is produced.

The metals most frequently used are chromium, nickel, zinc, copper, tinllead alloys and

noble metals . This study focuses on the general electroplat ing process , leaving out the

more exceptional processes .

figure 3.1 basic electroplating process

prelim inarytreatment s

wastewater

rinsewater

wastewater

rinsewater

277


3.1.2 Pre-treatment

Metal products to be electroplated need cleaning: grease, metal particles and dirt from

earlier processes are to be removed in order to get the right quality of deposition. Indus

trial degreasing of metal products often occurs with the aid of halogenated hydrocarbons ,

but in the Netherlands the electroplating industry for the greater part (95%) has changed

over to water-based degreasing agents (Barendregt et al., 1990). These agents contain

alkalis as the primary cleaning substance. Furthermore, other application-specific com

pounds are added. After the degreasing stage, the products are rinsed in order to avoid

pollution of other baths.

As part of the pre-treatment process, for the removal of oxide layers, degreasing is fol

lowed by etching. For this, anorganic acids are used, such as hydrochloric acid, sulphuric

acid, phosphoric acid, fluoric acid and nitric acid.

3.1.3 Main process

In the main process the metal products are immersed in the process bath and connected

with an external source of electrical current. The second electrode (anode) in the bath

consists of the metal to be deposited. The controlled electrical current through the system

results into a deposition of metal on the product to be electroplated and the electrochemi

cal dissolution of the metal anode.

In some cases, depending on the chemistry of the process, the deposition of metal onto

the product may occur without any electrical current. This so-called 'electroless' plating

has some industrial applications; they are part of the electroplating sector. This relatively

new process was introduced about 15 years ago.

The process liquid contains several chemicals which allow better control of the process

and better qualities of the deposited layer. Important components are certain chemical

compounds called 'metal complexes'. These compounds react with the metal atoms (ions)

in the solution, preventing them from precipitation as hydroxides and allowing better proc

ess control in general. Complexes affect the electroplating process. Therefore , their use is

SUbject to optimalisation.

Apart from complexes , there are other compounds involved in the main process, such as

those to increase gloss in the metal deposition, to stabilise the bath, to improve mechani

cal properties of the applied layers, and to reduce the surface tension of the liquid.

In some cases the electroplating baths are heated. The vapours may cause damage to

health and environment. Moreover, heated baths consume relatively large amounts of

energy.

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Technical Survey

3.1.4 Finishing

There is an important finishing treatment called 'passivation'. This is a process where the

metal product interacts electrochemically with the solution in the process bath (Vorm

Gouman et al., 1085). The result is a corrosion resistant and/or coloured surface , de

pending on the chemicals applied. Passivation is predominantly applied to zinc , where

three different surface colours can be obtained: yellow , blue and black. These processes

involve heavy metals; they will be discussed in more detail in section 3.4.4.

3.1.5 Product transport

The transport of products from one bath to another is an important factor in the contam i

nation of baths and rinsing water. Reduction of the drag of liquids is one of the focal points

in environmental measures.

3.2 Technological development

Technological developments in the electroplating sector over the past three or four dec

ades have been incremental. Most enterprises are small and have little or no research or

development capacity of their own. Almost all innovative developments originate from the

supplie rs. The relatively few integrated companies (where electroplating is part of the total

product ion process) do have some R&D capacity . The main issues are discussed below.

3.2.1 Chemicals

The chemical composition of electroplating baths is determined by the suppliers of these

chemicals. In most cases the owners of the installations are not cognisant of the chemical

contents of the materials they are working with. Developments in process chemistry have

led to less critical process variables and better management of deposited layers , even in

the case of complicated product surfaces .

3.2.2 New coating materials

Much effort is put into the deposition of alloys instead of single (elementary) metals . With

these alloys thinner layers can be produced without a loss of quality . Research in this field

takes place primarily in research institutes. The inclusion of other metal particles in metal

lic layers is also considered to give higher quality layers. Another example of a new mate

rial is tungsten, applied in some parts of car engines , in order to obtain very hard sur

faces.

Other product innovations are:

• non-allergic coat ings

• plating on plastics

• plating on ceramics

279


• coating with composite alloys, i.e. mixtures of metals with polymers or with ceramics,

for instance the inclusion of Teflon in layers with low frictional resistance.

For some applications ceramic layers may substitute electroplating. Ceramic layers are

produced by a process called plasma deposition (physical vapour deposit ion - PVD - or

chemica l vapour deposition - CVD). Up till now, this process is less cost-effective than

electroplating.

3.2.3 Process automation

Automation of the electroplating process is feasible only for those enterprises where the

number of products in each batch is not too small. Control of electrical currents , bath

chemistry, product transport, etc. may be automated if products and product flow are suf

ficiently homogeneous. Although this situation applies not only to those enterprises where

electroplating is an integrated part of a more extensive production process, but also to the

larger jobbers, process automation has found relatively limited application up till now. Re

search in this field focuses on increase of electrical current densities (for improved pro

ductivity) and improvement of chromium deposition (for better current efficiencies).


The most important environmental issues in the electroplating industry can be described

applying the usual categories : waste, air, water, soil and energy.

Process waste is found in waste water treatment systems: metal hydroxide solids and

metal containing solutions, including the used filters in these systems.

Air pollution arises from the emission of hydrogen gas and chromium acid from hot chro

mium baths, from evaporation of organic degreasing agents, and from NOx emissions

from etching baths with nitric acid. Especially with electroless plating of nickel (which is

the dominant metal in this process) there is the risk of emission of nickel salts; in the

Netherlands it can be considered as average practice that in these cases the air is

'washed' with special equipment.

In all waste water flows of all production stages traces of polluting chemicals can be

found: degreasing solutions, electroplating baths, etching solutions, passivation baths.

Metals as well as cyanides and organic halogenated compounds are involved.

Pollution of soil may occur when spoiling chemicals, such as organic halogenated com

pounds, cyanides and compounds of heavy metals.

Energyconsumption is an issue especially as regards heated chromium baths and the air

treatment equipment of electroless baths.

In the next section it will be described which technical solutions for these problems were

found or are still being developed.

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TechnicalSurvey


For several of the problems mentioned above, solutions have been developed, either by

means of new technologies, or by the use of less hazardous chemicals. Also good house

keeping may help in a number of cases, such as sealing of floors to prevent leakage of

chemicals, and thermal insulation of baths and rooms. In the production of metal parts

(drilling, turning, etc.) less oil is used now to reduce environmentally hazardous com

pounds right at the source of the electroplating process.

Environmentally relevant technological innovations in the electroplating sector can be

grouped into four categories, i.e. degreasing, reduction of rinsing water, cyanide reduc

tion, and passivation of zinc. Within each group several technical solutions may exist

alongside each other, so strictly speaking the term 'technological trajectory' does not fully

apply to each group separately. However, the classification presented here might be pre

ferred in order to obtain some overview of what is going on in the sector.

3.4.1 Degreasing

Technologies for degreasing of metal parts include degreasing by vapour, by boiling and

by electrolysis. Within each of these technologies innovative improvements have been

developed over time. These improvements will be described briefly.

Degreasing by vapour

Degreasing of metal parts by vapour from boiling halogenated hydrocarbons, such as

trichloro-ethene and perchloro-ethene, has been substituted for the greater part by de

greasing with water-based agents. The use of trichloro-ethene has been prohibited

worldwide, and for other halogenated degreasing agents standards for maximum emission

have been set. Water-based agents are, for instance, solutions of sodium carbonate

(soda) or soap in water, applied in ultrasonic vibration baths. Fully closed vapour de

greasing systems are available, but they require investments which are too costly for most

smaller enterprises.

Degreasing by boiling

Degreasing of metal parts by means of immersion in boiling alkaline solutions is average

practice now. The boiling causes agitation, which improves process quality. A disadvan

tage is the loss of liquid, so other means of agitation are applied also, in non-boiling solu

tions.

Most degreasing baths contain 'complexes' (see section 3.1.3), in order to prevent pre

cipitation of metal compounds, for instance hydroxides. Examples of complexes are cya

nide-compounds, EDTA and NTA. These are relatively hazardous compounds, so in may

cases they have been substituted by organic compounds, such as acrylates, gluconates

and fosfonates. A disadvantage of all complexes is their destabilising effects on water pu-

281


rification systems. Therefore , their use should be limited to lowest possible concentra

tions.

Degreasing by electrolysis

Degreasing by electrolysis yields very clean surfaces; the process is used as a final step

in the cleaning process. The cleaning effect is produced by the gas developed at the

metal surface during electrolysis .

Bath life extension

The increasing costs of disposal of chemical waste have led to the development of tech

nologies for an extended use of degreasing baths. For a longer use of baths it is essential

to avoid accumulation of chemical waste, oil residues, solid particles, etc.

The main technologies to prevent the accumulation of waste substances are:

• Skimming of free oil, floating at the surface of the liquid.

• Removal of emulgated oil, by membrane filters or by . •ans of electro-coalescence .

The filtering technologies are not yet common practice; they are not successful in all

cases, so smaller firms hesitate to implement them.

• Cascade baths (figure 3.2): the metal products to be degreased pass several baths,

whereas a small counterflow of liquid takes up the larger part of the chemical waste

and oil. This relatively simple technology saves cleaning liquids and its maintenance

costs are low.

In most cases combinations of these bath life extension technologies are used, because

different chemicals require different cleaning methods.

figure 3.2 cascade degreasing

----

282

scade degre ng

r---l

~.·0

Technical Survey

3.4.2 Reduction of rinsing water

Government regulations in the Netherlands (and other European countries) with regard to

the prevention of surface water pollution, induced water-saving production methods in

many sectors of industry, including the electroplating industry. Especially the large

amounts of rinsing water used in this sector have been reduced. The main technologies to

reduce rinsing water will be described below; they include: prevention of drag; rinsing res

ervoirs and cascade rinsing; spraying; low metal concentrations ; closed systems .

Prevention of drag

Transport of products from one bath to another implies unwanted transport of liquids and

chemicals. Reduction of this 'drag' will reduce the amount of rinsing water needed. The

main methods for drag prevention are:

• Dripping and tapping off the metal parts.

• Air knife: a stream of air from a narrow slit blows the liquid off the product. Feasible

only for products with flat surfaces.

• Wiping (figure 3.3): a sleeve wipes off the redundant liquid. Feasible for automated

processing of products with relatively flat surfaces.

• Marangoni knife (figure 3.4): this resembles the air knife, but the air is substituted by

nitrogen gas saturated with alcohol vapour. The result is a flow of liquid back into the

process bath. The Marangoni knife requires much lower gas pressures than the air

knife and, by consequence , produces less noise. However, application of the Maran

goni knife (which was recently developed by Philips) is not very successful up till now,

because the differences with the normal air knife are small, and costs are relatively

high.

• Addition of chemicals lowering surface tension, for fast drying.

figure 3.3 prevention of drag by wiping

Transporl bell

283


figu re 3.4 the Marangon i knife

Electroplating bath Sleeve lock

••Process

liquid

Transport belt

Rinsing reservoirs and cascade rinsing

In rinsing reservoirs, chemicals from the main process are accumulated, whereas the

water - especially with hot electroplating processes - slowly evaporates. After some time

the reservoir contents can be fed back to the process bath, which results in less chemical

pollution and lower water consumption.

Reduction of water consumption can be obtained also by the use of cascade baths, de

scribed in 'Bath life extension'.

Spraying

Another technology to reduce water consumption is based on spraying a water mist over

the products pulled from the electroplating bath. The water mist takes up the chemicals to

be rinsed and flows back into the bath. Dilution of the bath has to be balanced by evapo

ration of water ; therefore this technology is feasible only with hot electroplating baths

(nickel, chromium).

Low metal concentrations

Reduction of metal concentrations in the electroplating process baths has a number of

advantages. Apart from the reduced drag to rinsing baths, and the reduction in the

amounts of rinsing water needed, the amount of solid wastes (hydroxides) resulting from

the purification of waste water flows is also significantly lower. The application of lower

metal concentrations has been developed during the past five years or so. Lower bath

concentrations reduce the rate of electroplating. On the other hand, some companies

strive after higher electroplating rates, so in practice there are two opposing trends in this

respect.

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TechnicalSurvey

Closed systems

Environmental considerat ions in the electroplating sector have encouraged the develop

ment of closed systems. In practice, closed systems have been realised for the main

process only (electroplating without pre-treatment and finishing stages), while exclusively

applying to water ,

'Closed' systems suffer from two problems:

a, dilution by the liquids from preceding processes and from rinsing, and

b. pollution by chemicals developing during the electroplat ing process.

Closed systems are not very popular yet. There are several reasons for this: first of all

they require high investments and secondly they have a poor reputation because of a

number of recent pilot projects failing to produce favourable results. Moreover, closed

systems are not feasible for all electroplating processes. However, with rising costs of

water cleaning, we see an increase in the number of water recovery systems, especially

in the larger enterprises. Systems for separate recovery of all metals are still scarce ,

3.4.3 Cyanide reduction

As was pointed out earlier (section 3.1.3), a certain category of chemicals, called com

plexes, is added to the electroplating bath to slow down the process of deposit ion (for

better quality of the deposited layer, also when the surface is irregUlar). One of the most

important complexes is cyanide, used in electroplating with metals such as copper, zinc,

silver and gold, Cyanide, however, is highly poisonous, and a number of technologies

were developed to reduce its application in the electroplating process,

The major technolog ies are:

• detoxification by oxidation to carbondioxide and nitrogen gas

• for zinc electroplating :

- substitution of cyanide by alkaline or acid compounds

- recently: electroplating in a neutral environment

• for copper electroplating, if slow processing is no problem:

- alternatives for cyanide.

For copper (most applications), silver and gold, no satisfactory alternatives are available.

3.4.4 Passivation of zinc

In certain applications of zinc deposited on metal products, the zinc surface is 'passivated'

(see section 3.1.4) by means of electrochemical processes involving chromium-IV (Cr-VI,

i.e. chromium in valency state six) and silver. These metals are harmful to the environ

ment.

285


Research is goingon to find substitutes:

- for blue passivation: Cr-VI mightbe replaced by Cr-III andcobalt

- for yellowpassivation: Cr-VI-free processes are being researched- for black passivation: silver-free processes are underdevelopment.

Cr-VI-free passivation processes are still in an experimental state; up till now there are noinstallations in operation.

3.4.5 Electroplating of plastics

Electroplating of plastics is an example of a product innovation in electroplating. It is a

relatively new technology, which was introduced about 20 years ago. The process in

volved the following mainsteps (in practice thereare about20 steps!):

- cleaning: degreasing, etc.

- etching: production of a 'rough' surface, for betterbinding of the subsequent layers

- nucleation: production of a first thin metallayerby chemical deposition- electroless plating: production of an intermediate layer

- electroplating: mainly with copper, nickelor chromium.

The etching process useschromium acid, which is harmful to the environment.

Thereare two directions of innovation in this respect:

- substitution of chromium acid by other anorganic acids, in combination with organic

solvents

- reduction of the numberof process stepsby integration of a numberof treatments: this

simplifies process handling, leadsto lowercostsand reduces environmental hazards.


In this chapter an overview will be given of the status of the innovative technologies asdescribed in the previous chapter. The definitions for the various stages are given inchapter 1 of this report. The information is obtained from experts in the electroplating in

dustry and from suppliers. Differences in statusmayoccurover thevariousEU-countries.

3.5.1 Degreasing

In section 3.4.1 three differentmethods to degrease metalproducts were given. Only two

of them can be described as a technological trajectory: degreasing by vapour and de

greasing by boiling. Apart form these technologies, various measures dealing with the

extension of bath life have been included in this section, because these measures are

relatively oftenapplied with degreasing baths.

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Technical Survey


Halogenated hydrocarbons were used (and in some places still are used) in the first

stages of degreasing, in combination with degreasing by boiling and electrolytical de

greasing as a finishing stage. Ultrasonic cleaning with soda or soap solutions can be con

sidered as the main substitute of the hydrocarbon process.

process

trichloro-ethene

perchloro-ethene ; other hydrocarbons

water W. soda or soap; ultrasonic vibration

closed systems

obsol.

+

+

avopract.

+

best pract. technofront.

+


Degreasing by boiling in alkaline (water-based) solutions is average practice now, but the

application of metal complexes still is an issue. Substitution of cyanides, EDTA and NTA

by organic complexes is best practice in most countries .

process

boiling of alkaline solutions

+ hazardous complexes (cyanide, etc.)

+ less hazardous (organic) complexes

Degreasing: bath life extension

obsol. avopract.

+

+


+

The relatively simple technologies for the removal of oil and other polluting materials are

average practice now. The membrane technologies can be divided into ultramembrane

and micromembrane filtering, depending on the size of the particles to be filtered.

process

no technologies for bath life extension

skimming of oil; cascade baths

membrane filtering

obsol.

+

avopract.

+


+


Most technologies for the reduction of rinsing water are average practice now. Exceptions

are the use of surfactants and the Marangoni knife in the prevention of drag, spraying in

stallations, the use of low metal concentrations , and the application of closed systems for

the main process.

287


Reduction of rinsing water: prevention of drag


dripping , tapping +

air knife +

wiping +

lowering of surface tension +

Marangoni knife +

Reduction of rinsing water; rinsing reservoirs and cascade rinsing

The absence of any rinsing reservoir or cascade rinsing is obsolete in the Northern Euro

pean countries; the Southern European countries mayshowa differentpicture.

process

no rinsing reservoirs andlorcascade baths

rinsing reservoirs and/or 1- or2-step cascade baths

3-step (or more) cascade baths

Reduction of rinsing water: spraying

process

no spraying installation

spraying installation present

obsol.

+

obsol.

+

avopract.

+

avopract.

+


+


Reduction of rinsing water: use of low metal concentrations

process

normal to high metal concentrations

lower metal concentrat ions

obsol. avo pract.

+


+

Reduction of rinsing water: closed systems

Closed systems provide for continuous cleaning of the main bath during processing. The

cleaning systemdescribed in Appendix A.2.1 is the traditional cleaning system. However,

this is usedonly as an end-ofpipetechnology in cleaning waste water. The othercleaningtechnologies aredescribed in A.2.2, A.2.3andA.2.4.

288

process

no application of closed systems

water recovery only

recovery of metals with ion exchange

recovery of metals w~h eledrolysis

recovery of metals w~h membrane filtering

obsol.

+

avopract.

+

Technical Survey

best prado techno front.

+

+

+

3.5.3 Cyanide reduction

The traditional method to reduce cyan ide concentrations is based on oxidation. In some

countries, alkaline or acid processes - for zinc electroplating - made cyanide obsolete, but

in the table below these substitutes are still considered as best practice.

process

no special provisions for cyanide reduction

reduct ion of cyanide by oxidation

applicat ion of alternatives for cyanide

for zinc: application of neutral process baths

3.5.4 Passivation of zinc

obsol.

+

avopract.

+

best prado technofront.

+

As was pointed out in section 3.4.4 . for the passivation of zinc alternat ive technologies are

under development.

process

''1ith chromium-VI and/or silver

J·tt, alternative metals

3.5.5 Electroplating of plastics

process

etching with chromium acid

substitution of chromium acid

reduction of number of process steps


obsol.

obsol.

avopract.

+

avo pract.

+

best prado technofront.

+

best prad o technofront.

+

+

The major ity of the enterprises in the electroplating sector is small or medium-sized. Re

search and development is done only by a few larger companies, for whom the electro

plating process is part of a more extens ive product ion line. The equipment and chemicals

suppliers are important actors in most innovation processes.

289


With the remarks on actorsand factors in chapter 1 of this report in mind, we can summa

rise the situation in the electroplating sectors as follows.

Use of closed systems in degreasing processes

Closed systems for vapourdegreasing are developed by electroplating equipment suppliers in response to government regulations on (halogenated) hydrocarbons. These sys

tems, however, are relatively expensive, so that smallenterprises cannotaffordthem.

Membrane filtering in bath life extension measures

Bath life extension methods havedeveloped as a consequence of increasing costs of dis

posal of waste water. The technologies of membrane filtering derive from general water

treatment installations; they are notapplicable to all electroplating installations.

Reduction of rinsing water

In the Netherlands, government regulations as to the pollution of surface water stimulated

the electroplating branch to adopt and adapt available water-saving technologies. The

relevant branch organisation offers its members courses andseminars on the subject.

Use of the Marangoni knife in the prevention of drag (reduction of rinsing water)

The Marangoni knife was developed by Philips' electroplating department in co-operation

with NOVEM, the Dutchgovernment-supported funding organisation for energy and envi

ronmental research. The system appears to have little advantage over the ordinary air

knife, so that application up till now is very limited.

Use of spraying installations in the reduction of rinsing water

This technology is applicable only for hot electroplating baths. It is partof the research into

closed systems. In the Netherlands the systemis developed and offeredby the engineer

ing company HOLEC.

Use of lower metal concentrations in the reduction of rinsing water

The most relevant application is in electroplating of zinc, in other cases the technical pos

sibilities for reduction of metalconcentrations are muchsmaller. The hazardous properties

of zinc are under discussion now, so electroplating firms accept lower productivities with

zinc electroplating (due to the lowerconcentrations), in anticipation of further repulaton of

the use of zinc.

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Technical Survey

Useof closedsystems in the reduction of rinsing water

Again the rising costs of waste water cleaning favours the introduction of closed electro

plating systems. High investments, insufficient technological reliability and relative high

process specificity are reasons for slow diffusion of closed systems.

Cyanide reduction

The research into zinc electroplat ing in alkaline or neutral environments is still going on by

TNO.

Passivation of zinc

The research into zinc passivation with alternative metals is performed by R&D organisa

tions and suppliers .

Electroplating of plastics

Studies into the reduction of the number of process steps are going on with American and

German equipment suppliers.

3.7 Literature

(Anon.) (1987), Afva/waterprob/ematiek bij de oppelVlaktebehandeling van meta/en; Min.

Verkeer en Waterstaat, CUWVO, Den Haag

Barendregt, w., B. Loos (1990), Ontvetten; SPIN-reeks nr. 736301 133, RIVM, Bilthoven

Boer, R. de, J.J.M. Brandsma , G.G. Toonen (1991), Handboek Ga/vanotechniek; Stichting

Bevordering Galvanotechniek, V.O.M., Bilthoven

Euro Info Centrum Midden-Nederland , IMd Micon (eds.) (1995), ECO Management Guide;

Bedrijfsmode/ metaa/- en e/ektrotechnische industrie ; H.D. Tjeenk Willink , Alphen aan den

Rijn

Groot, K.E. de, E.H. Heuvelman (1990), /nformatiebunde/ ga/vanische bedrijven; Minis

terie van VROM , Den Haag

Joosten , P.H. (1992) , Het Marangoni-snijmes snijdt aan twee kanten; voorde/en voor mi

lieu en produktkwa/iteit; Proceedings Symposium Verwijdering zware meta/en uit afva/

water; VOM, Bilthoven

Kemp, R.P.M., A.A. Olsthoorn , F.H. Oosterhu is, H. Verbruggen , m.m.v. J. van Swigchem

en T. Daamen (1991), /nstrumenten voor de stimu/ering van milieutechn%gie;

Beleidsstudies Technolog ie Economie nr. 14; Ministerie van Economische Zaken, Den

Haag

291


Mortier, J.w. du, J.P.M. Ros (1992), Ga/vanische bewerkingen; SPIN-reeks nr. 736 301

109, RIVM, Bilthoven

Ram, AAP., J.F.M.van Oriel (1994), /nventarisatie; standtijdverlenging van reinigings- en

ontvettingsbaden; InfoMiI, DenHaag

Velthuis, AJ.M. (1995), Verwerking van nikke/houdend afva/ van ga/vanische processen;

Philips Galvanotechniek, Eindhoven

Vlieger, G.J. de (1992), Emissiebeperking door midde/van 'ges/oten' produktiesystemen;

Proceedings Symposium Verwijdering zwaremeta/en uit afva/water; VOM, Bilthoven

Vlieger, G.J. de, W. Barendregt (1996), Watersysteemverkenningen 1996; Kostenstudie

naar zuiveringstechnieken in de ga/vanische industrie; RIZA, Lelystad

Vlieger, G.J. de, Milieupreventieve maatrege/en; VOM, Bilthoven

Vork, F.TA (1995), Brongerichte aanpakbeheersten vermindert ga/vanisch afva/;Metaal

& Kunststof, nrs. 23/24, pp. 14-17

Vorm-Gouman, E.van der, P.J. van Wermeskerken (1985), /nformatiebunde/ ga/vanische

bedrijven; Ministerie van VROM, DenHaag

3.8 Appendix A.1 Experts and organisations consulted

Dr. AJ. Bosch TNO Industrie, Apeldoorn

G.J. de Vlieger Stichting Vereniging Oppervlaktetechnieken Metalen (VOM), Bilthoven

Dr. F.TA Vork Philips Galvanotechniek, Eindhoven

3.9 Appendix A.2 Technologies for purification of waste water

A.2.1 Detoxification - precipitation· dehydration

One single installation may takecareof detoxification, precipitation anddehydration.

Step 1: Detoxification refers to a) the reduction of chromium-VI to the less hazardouschromium-III ; b) the oxidation of cyanide to carbondioxide and nitrogen gas.

Step 2: Precipitation is the conversion from metal-ions in solutions to insoluble matter

('slUdge', mainly hydroxides).

Step 3: Dehydration is the process of filtering the water from the sludge. The result is aflow of clean water and a more compact metal-containing sludge. In most cases this

sludgecannotbe re-used, so it has to be treated as chemical waste.

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Technical Survey

A.2.2 Ion exchange

Ion exchange is applied in cleaning diluted rinsing water and water from the installations

mentioned under A.2.1 . It involves a kind of chemical filter that can be recycled when

saturated with metal-ions. There is no actual decomposition of metal compounds, so the

final concentrated residue needs further cleaning .

A. 2.3 Electrolysis

Purification of waste water by electrolysis is based on the electroplating process itself.

This technology can be appl ied for the removal of most kinds of metals, but it is still rela

tively new for the sector. Disadvantages are the formation of hydrogen and chlorine gas

during processing; moreover, the deposited metal is of low quality and cannot be re-used

without further improvements.

A. 2.4 Membranes

There are several types of membrane that may filter certain materials (the larger mole

cules) from waste water systems, degreasing baths, etc . Depending on the size of the

pores in the membrane, one may distinguish ultramembranes and micromembranes. The

diffusion of membrane filtering technologies is slow due to failure of some pilot projects in

the sector.

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Technical Survey

4 Environmental innovations in textile finishing

4.1 Basic processes

Throughout this description of basic processes in textile finishing, reference will be made

to processes for cotton and synthetics only. Worldwide, these two materials take up about

97% of all textiles (cotton: 44%, synthetics: 53%).

In textile finishing processes, special properties are given to fibres, yarns and fabric.

These properties may involve colour, roughness, gloss, weather resistance, etc. After the

finishing process, the fibres, yarns and fabric will be used further, for instance in the

clothing industry.

Most finishing processes have a basic similarity: the textile is submerged in a bath with a

water-based chemical solution or dispersion. After the submersion, part of the chemicals

are fixed onto the textile and the rests is washed out. The wet processes take place in a

so-called 'pad', which consists of a trough with a press mechanism. The trough is filled

with the process liquid, through which the fabrics are fed. After this step, superfluous liquid

is squeezed from the material and fed back to the pad.

There are four main processes:

• pre-treatment , such as washing, bleaching

• dyeing

• printing

• finishing (wet- and dry-finish).

Within these main processes there are many kinds of treatment, depending on the prop

erties required. The most important ones will be discussed here briefly.

4.1.1 Pre-treatment

Before the actual dyeing or printing of textiles, they need degreasing and cleaning, as part

of the pre-treatment process. There are chemical and mechanical processes in this stage.

Chemical pre-treatment

Cleaning

In order to be sure of a strong attachment of the dyes to the fibres, polluting materials

such as grease , oil, resin, pectin and wax should be removed. Therefore , the textiles are

washed with chemicals such as soda and sodium hydroxide dissolved in water.

Mercerising

Mercerising is a pre-treatment for cotton, producing a silk-like gloss. Moreover, it improves

the binding properties for dyes to the fibres. The mercerising process involves the sub-

295


mersion of the cotton in a cold, concentrated alkali solution, after which the chemicals are

washed out by water of about ao·c.

(De-)sizingIn order to prevent breaking of the yarns during weaving, they are treated with starch or

starch derivatives. After weaving, this starch has to be removed; this can be done with

surface-active agents, combined with enzymes (at 60 to 70°C) or oxidants (at 90°C

maximum).

ThermofixingIn order to prevent shrinking, synthetics undergo a heat treatment with hot air of about

200°C.

BleachingBleaching removes a number of 'natural' dyes from the textile. This step is required in or

der to obtain an even distribution of dye (and colour) in the dyeing step. For bleaching,

chemicals such as hydrogenperoxide or (in some countries) sodium hypochlorate are

used most often, but optical bleaches are used also. The latter have a masking effect on

the colour of the materials. After bleaching, the textile is pre-died by means of a vacuum

system, a centrifuge or a press, followed by drying with hot air.

Mechanical pre-treatment

ToppingThis involves shaving of the fibre ends.

SingeingThe fabric is fed along an open burner, which slightly burns the fibre ends.

4.1.2 Dyeing

For the production of coloured fabrics, numerous dye-stuffs are available. On the basis of

their chemical composition , these dyes can be divided into about 20 groups. Of these 20

groups , the azo- and anthrachinon-dyes are the most important. About 60% of all dyes

applied are azo-dyes .

The selection of a certain type of dyeing process is determined by the kind of fibre. Each

kind of fibre requires its own type of dye and dyeing process, for optimum effectiveness

(degree of fixing). For the Dutch situation, the combinations used most often are pre

sented in table 4.1.

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Technical Survey

lable 4.1 types of dye for given fibres

Type of dye silk acryl polyester cotton

alkaline x

dispersed x

direct , vat , naphto l x

acid, metal-comp lex x

react ive x x

nylon wool

x

x

x x

The dying process may proceed in two ways: the batch process and the continuous proc

ess.

Batch process

In the batch process, a certain amount of textile is brought into contact with a certain

amount of dyeing bath, in a vessel that may have various dimensions. The dyeing liquid

penetrates the fibres, and the dye is transferred from the liquid phase to the fibre until an

equilibrium is attained. In this process the so-called liquor ratio is important. This is the

ratio between the textile mass and the volume of the dyeing bath; it depends on the type

of dyeing equipment.

During the dyeing process, the dye is attached 'permanently' to the fibre. With synthetics ,

this fixing occurs through heating up to about 130°C (High Temperature (HT) process) .

For other materials this temperature is about 95°C maximum. Chemical fixing of dyes is

also possible: with naphtol dyes the fixing takes place through the formation of a dia

zonium compound.

For batch processing, various kinds of equipment are available, depending on the kind of

material to be dyed. The most important technologies involve:

• the jigger, for liquor ratios of 1/3 to 1/6

• the jet , for liquor ratios of Y. to 1/10

• the reel vat, for liquor ratios of 1/20 to 1/25.

Continuous process

In the continuous process, the material (fabric or yearns) is fed continuously through the

dyeing bath, where it absorbs part of the liquid. The dye is subsequently fixed by raising

the temperature or by a chemical process, as was described earlier.

For both the batch process and the continuous process, the so-called fixing ratio is im

portant. This is a measure for the amount of dye applied and the amount fixed. It will be

clear that this ratio is of relevance for the economy of the process as well as for its envi

ronmental implications. Table 4.2 gives consumption ratios and upper and lower limits for

fiXing ratios for a number of dyes.

297

Adoption of Environmenta/lnnovations

table4.2 consumption and fixing ratios for varioustypes of dye

type of dye consumption (% of lotal consumption)

acid 11.3

naphtol 2.8

alkaline 1.6

direct 6.5

dispersed 8.1

metal-complex

reactive

val

4.9

14.6

32.4

fixing ration (%)

best worse

93 80

95 90

98 97

95 70

95 80

98 95

95 50

95 80

4.1.3 Printing

For printing of textiles, a coloured paste is applied to one side of the fabric, where more of

less 'print through' occurs, i.e. colouring of the reverse side. Various printing technologies

are available:

Screen printing (sheet-fed or rotary)

With screen printing the coloured paste is squeezed through a metal gauze onto the fab

ric. Parts of the gauze are not permeable, according to the desired pattern. For each col

our a separate screen is required.

Transfer printing

With this process. the print is first made on another material, for instance paper, after

which this paper is brought into close contact with the textile. During this contact, the

printed image is transferred to the textile.

Rouleaux printing

This is a kind of gravure printing, where the pattern to be printed is engraved into a metal

cylinder. The pattern is filled with paste, the cylinder is pressed against the fabric, and the

paste is transferred onto the fabric. This process is used only incidentally now.

4.1.4 Finishing

Finishing treatments are applied to create specific properties of the textile. These treat

ments involve mainly the impregnation with finishing chemicals and, in some cases, coat

ing. The application of finish involves submersion in one or more baths, pressing out the

superfluous liquids, drying, and fixing at increased temperatures. The treatments most

often applied are:

• Crease-res isting: impregnation with chemicals that produce polymers during fixing.

298

~ .- ;~

Technical Survey

• Anti-static: treatment with chemicals such as magnesium chloride, poly-ethylene gly

col , poly-alkylenes .

• Shrink-proof: the wet fabrics are dried while stretching them against the direction of

shrink. Sometimes resins are used.

• Water-repellent: treatments with silicones, aluminium or zirconium soaps, fluorocar

bon-resins, or paraffines.

• Resistance to rot, moth and mould: for these treatments, aromatic hydrocarbons and

organic tin-compounds are used. In some European countries chlorinated compounds

are used.

• Fire retarding: treatment with organic phosphorus compounds, halogenated com

pounds, or - in some countries - antimony trioxide. In the Netherlands, the latter com

pound is prohibited.

• Softening: a treatment for all knit-wears; involves silicones and quaternary ammonium

ions.

4.2 Technological development

There is a great number of developments in process technologies for textile finishing. The

most important ones will be described briefly.

4.2.1 Current technologies

Minimumapplicationby atomising

Atomising is a method for application of small quantities of chemicals or water onto tex

tiles. The liquid to be applied is pumped to fast-rotating discs, installed over the textile

web. The discs produce small droplets, which are sprayed onto the web. With this system

quantities as low as 10 to 30% (of the dry textile weight) can be applied, as compared to

60 to 80% with the traditional technique (submersion). Advantages of the system are en

ergy saving for drying, and increase of productivity due to higher web speeds. This tech

nology is mainly found in the application of biocides (fungus- and mothproofing of textiles) .

Minimumapplicationby means of a rol/er

Another method for application of small quantities of chemicals uses a roller, with a con

struction similar to that in an inking system of a printing press. The roller transfers the liq

uid from a bath to the textile web; it is in contact with liquid bath and web simultaneously .

The amount of liqUid transferred per unit of time is controlled by the rotating speed of the

roller. This system is in use for the application of finishing chemicals ; application of paints

is not possible due to uneven distribution. Advantages of the roller system are energy

saving, higher web speeds and - in some cases - saving of chemicals.

~ ..~ 299

Adoption of Environmentat Innovations

Minimum application by means offoam

This is a printing technique, developed for rotary screen printing. The paint applied to the

printing position of the printing press is mechanically stirred before printing. The system is

closed; the required quantities of paint are pre-set. Application is mainly for pigment dyes.

Foam printing requires minimum coverage of 50% per printed position; multi-colour print

ing is possible only in combination with conventional printing. Advantages of the system

are: higher quality of the printed fabric and the print itself; reduced quantities of paint re

quired for printing, up to 50%; less waste of paint; lower energy consumption and higher

printing speeds. Disadvantages are: longer change-over times; minimum quantities of

paint of at least 5 kgs for start-up; extra chemicals required for foam production.

Low liquor dyeing equipment

In specific cases of batch dyeing, for instance dyeing of relatively short pieces of fabric

(some hundreds of metres), equipment can be used which favours reduction of dyestuff.

In this equipment the fabric repeatedly passes the dyeing bath, be it by means of shuttling

or by means of an endless loop construction. Liquor ratios may improve from 1/10 to 1/3

to 1/4.

Vacuum technologies

For the removal of liquids from textile webs, vacuum technology may be applied. The wet

web is pulled along a bar with a slit, through which the liquid is taken up by applying a

vacuum within the bar. The amount of remaining liquid is lower than with convent ional

pressing, which implies energy saving with subsequent drying. Best results are with syn

thetics, where final amounts of liquid as low as 20% are feasible. The liquid taken up by

the system may be reused, after filtering. The system may be applied for taking up water,

in one of the drying stages, or for taking up chemicals, before washing operations. This

leads to reduced consumption of water and energy.

Combined dyeing baths

Fabrics consisting of combinations of cotton and synthetics can be dyed in one bath,

containing two different dyes. The synthetic part of the material is dyed with a dispersed

dye; after drying, the fabric can be heated for dye fixation. In a second run the cotton is

dyed with a vat dye, after which other chemical reactions are applied for fixation. The main

advantage of this process is the reduction of the number of process baths and the reduc

tion of waste material.

Transferprinting

With transferprinting, first a coloured pattern is printed on paper by means of - in most

cases - rotary screen printing. During the next step the printed image is transferred to the

300

TechnicalSurvey

fabric by pressing the paper at temperatures of about 200°C to the web. The dye is

transferred to the fabric by evaporation; further treatment of the fabric is not required.

Transferprinting often is a continuous process, where web speeds are relatively low, i.e.

about 10 m/min. (compare normal rotary printing speeds of textile: 30 to 50 m/min.).

Transferprinting was developed for printing of polyester; recently the system was adapted

to print cotton, the 'Cotton Art' process. For cotton, reactive dyes are used, whereas poly

ester requires dispersed dyes. Advantages of the system for polyester are: washing, dry

ing and fixing at elevated temperatures are not required, waste water and waste paint are

not involved. It is a flexible process, suitable for short runs. For cotton, an extra washing

treatment is required, to wash out non fixed parts of the dye.

Pad/batch systems

In these systems, longer pieces of cotton (up to many thousands of metres) are treated in

a pad, after which the material is stored for a prolonged period of time (for instance 24

hours) to improve fixing of the (reactive) dyes. This (cold) storage replaces the traditional

heating process, so that energy is saved. A disadvantage of this process is the slow

throughput: when many batches in different colours have to be processed like this, stor

age space will be a problem.

Reactive dyes with higher fixing ratio

When working with traditional reactive dyes - dyes that are fixed to the fibres through

chemical reactions - it is accepted that 20 to 40% of the amount of dye-stuff applied is

lost, due to incomplete fixing or early decomposition of the dyes after introduction into the

system. This leads to relatively large amounts of waste water. Improvement of the fixing

ratio can be attained by using other combinations of dyes, composition of the baths, in

cluding auxiliary chemicals, and process control parameters. Suppliers of dyes are sup

portive in this respect by offering computer software for composition and control parame

ters. Optimisation of all parameters may improve fixing ratios up to 80 to 99%. Extra op

portunities are offered by the use of so-called bifunctional reactive dyes. These dyes have

two instead of one chemical group in each molecule for reacting with the fibre. It is ex

pected that all these developments and opportunities will lead to an increased use of re

active dyes. At present, the share of reactive dyes in the total dye consumption in the

Netherlands is 20% - as a maximum; in other European countries this will be about 30%

or higher.

Software and hardware for better image processing in textile printing (computer

aided pre-press)

Optimising the use of dyes in dyeing and printing of textile is an important issue for the

sector and its suppliers. Image processing in textile printing can be compared now with

the pre-press stages in offset printing. This means that the total trajectory of scanning a

301


design, selecting dyes and recipes, colour previewing, proofing and correction on com

puter screens, and finally printing under controlled conditions, is under complete digital

control. Proof runs are made with jet printers; production runs use computer-controlled

paint compositions .

Software for reusing paint

For rotary screen printing, systems are developed for saving remainders of paint, while

recording their relevant data. This gives the opportunity to reuse this paint in new runs.

4.2.2 New technologies

Minimising remainders of dyeing baths (dyeing automation)

Opportunities for the reduction of remainders of bath liquids after dyeing are given by a

more accurate prediction of the amounts of dye required, With an on-line measuring sys

tem the consumption of bath liquid can be determined during dyeing, On the basis of

these measurements the amount required for the total batch can be calculated. Related

systems for on-line measurement of the dyeing result (colour measurement on the wet

web) are also available. Feed-back of the colour measurements to the dye application

system closes the control system, which can be set to optimum conditions.

Minimising system content of rotary screen presses

Starting a production run in rotary screen printing involves filling pumps, pipes and the

actual printing unit with paint, i.e, about 4 kg of lost material. In newer systems this loss of

paint has been reduced to about 1.5 kg, either by reducing the relevant dimensions of the

machine or by recollecting paint. These kinds of innovations are important in situations

where production runs gradually become shorter and shorter , to a few hundreds of metres

of total length. Costs savings by reduction of paint loss and by reduction of paint disposal

are significant.

Mechanical treatment for softening

Softening of fabrics may be obtained either by making the material more voluminous or by

making it more smooth. In both cases the user will perceive it as 'soft'. In some cases the

traditionally chemical process of making the fabric more voluminous can be replaced by

mechanical treatment, especially for colton. Soft materials become more fashionable now,

so these mechanical technologies recently show a wider adoption.

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Technical Survey

4.2.3 Technologies under development

Dyeing with supercritical carbondioxide

Under certain conditions of temperature and pressure, carbondioxide (C02) can be trans

ferred from the normal gaseous state into what is called the supercritical state. In this

state, CO2 behaves as a liquid with a very low viscosity . It appears that dispersed dyes

can be dissolved in supercrilical CO2, and that transfer of the dye from this solution into

polyester fibres may occur very effectively in relatively short periods of time, i.e. 10 to 20

minutes. Batches of yarns as well as fabric can be treated in this way. There is a rest of

only 2% of the dye in each batch, which can be reused. Advantages of the process are

the complete lack of water, short production runs, no auxiliary chemicals, no finishing

treatments, no drying stages. A disadvantage is the need to invest in complex equipment,

and the limited batch sizes.

Ink jet printing

Printing of textile with ink jet technology is an accepted technology in carpet printing, for

textiles the technology is under development, especially in Japan. There are two systems:

the 'drop-on-demand' system - every drop of ink is used to build up the pattern - and the

'deviated continuous jet' system - where the pattern is written on the textile with a very thin

ink jet, with feed back of the non-used ink. Ink jet printing can be done with almost all

types of dye on almost any kind of fabric: cotton, synthetics, wool, etc. In practice, the

system is expected to offer a simple, fast, flexible and cost-effective method for printing

short runs of textile. Energy consumption and amounts of waste are low.

Concentrating chemical waste by evaporation

For cutting back costs of removal of chemical waste , reduction of waste volumes through

evaporation of water can be attractive. Research is going on to determine the conditions

under which these evaporation techniques will be feasible, and what can be done with the

remaining chemicals and water.

Replenishment of dye

With certain dyes it is feasible to replenish the dyeing bath after each batch. Due to

chemical degradation and other forms of pollution, the maximum number of batches is

about five. This technology is in an experimental stage, especially with dispersed dyes on

synthetics. Advantages are expected to be found in the efficiency of dye consumption .

Filtering technologies

With the present state of the technology it is commercially not yet feasible to use mem

brane filtering for purification of waste water and recollection of chemicals, with the excep-

303

50 - 4000nm (nanometer, 1/1000 micrometer)1 - 100 nm

0.6 - 2 nm0.1 - 1 nm.


tion of one application: the recovery of indigo with ultrafiltration. A number of systems is

underdevelopment:- microfiltration particlesize- ultrafiltration- nanofiltration

- reversed osmosis

A major problem with these filtering techniques is the purification and reuse of the re

maining chemicals, i.e. 5 to 10%of the total waste water flow. In the USA, membrane fil

tering technologies are used for a number of years now, for the recollection of synthetic

sizes.


The main themes in environmental innovations in textile finishing refer to the reduction of

chemicals in wastes, the reduction of energy consumption and the reduction of water con

sumption.

Chemical wastes are mainly dyes. Sources of dye wastesare the remainders of the dye

ing baths, printing pastes and washing processes. Moreover, cleaning of dyeing and

printing equipment and the regeneration of water purification systems are also sources of

dye wastes. It will be clear that due to differences in toxicity, biological degradability andfixing ratio, each(groupof) dye requires its own treatment.

A certain groupof azo-dyes - about20 different compounds - showscarcinogenic proper

ties, caused by the production of aminesduring degradation. This means that for usersoftextiles treated by thesedyes, health problems mayoccur.

Apart from dyes, sulphuric acid, sodium hydroxide and several kindsof salts can be foundin waste material. In the Netherlands, antimony - usedas a catalyst in polymerproductionand in fire retarding finishes - is not allowed in textile finishing processes any more, but

this mightbe differentin otherEuropean countries.

Energyconsumption is also a major issue in textile finishing. In manyparts of the dye application and fixing processes, heat treatments are required, most of them involving

steam. The production of steam accounts for an important part of total energy consump

tionof the sector.

From the description of the basic processes it follows that large amounts of water are involved in many sub-processes in textile finishing. For one kilogram of textile, 50 to 100

litres of water are required, on average. Process innovations focusing at the reduction ofwaterconsumption will be described below.

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Technical Survey

4.4 Technological trajectories and technology status

According to the definition of 'technological trajectory' (a series of technical improvements

in succeeding generations of a key-element of a basic design), it would be required to se

lect a number of key-elements within one basic design of textile finishing. However , it is

hardly possible to define one basic design: textile finishing is a collection of processes,

each of which has its own design and key-elements. Therefore, for an overview of rele

vant innovations, the three main environmental issues given in the preceding section will

be taken as 'key-elements' . Each of the technological developments described in section

2 will be introduced then as an innovative step in one of these key-elements . With this

method it will still be possible to give an assessment of the status of the technology in

terms of 'obsolete', 'average practice', etc. Other than in the previous parts of this report,

the technology status will be given immediately after the description of each trajectory.

4.4.1 Reduction of dye consumption

Foam printing

The foam printing technology was developed as an alternative for rotary screen printing.

The reduction of dye consumption can be considerable· up to 50% ., provided that the

production runs are not too short. The technology is relatively new, it was developed dur

ing the late 70's and early 80's. The actual application in a commercial environment is not

yet fully developed, because of present requirements of textile prints: many colours in one

print. With foam printing only two colours in one print are feasible.

Status of foam printing

process

rotary screen printing

printing with foam

obsolete avo pract.

+

best pracl. technofrontier

+

Transfer printing

As with many of the newer technologies , transfer printing combines reduction of dye with

energy and water saving. It is a relatively standard technology now, the first patent was

applied in 1958, and the first industrial applications came in the later 60's. At present the

market share of transfer printing in the Netherlands is estimated at about 5%, in volume of

printed textile.

305


Status of tranfer printing

process


transfer printing of polyester

transfer printing of cotton

obsolete avopract.

+

best pract. technofrontier

+

+

Reduction of systemcontent

Rotary screenpresses for textileprinting traditionally take up about4 kgs of paint for each

production run, whichamount can be considered as loss. By minimising the dimensions of

the machine and other measures, this losscan be reduced to about 1.5 kgs. The technol

ogy is relatively new, but (all?) new machines now are equipped with this kind of paintconserving constructions.

Status of reduction of system content

process


machines W. low system content

obsolete avopract.

+


+

Improvement of fixingratios

New reactive dyes and new, optimised control procedures to use them may lead to im

proved fixing ratios; increases from 60-80% to 90-99% have been realised. Although thetechnology at present is relatively well-known, its application in textile dyeing is not yetcommon practice.

Status of improvement of fixing ratios

process

traditional dyeing/printing

improved reactive dyes/bath como.

obsolete avopract.

+


+

Computer-aided pre-press

All the advanced digital technologies for designing, production preparation, proof running

and actual production in textile printing involve many aspects of productivity, productioncost, productquality and environmental issues. As far as reduction of dye consumption is

concerned, the opportunities for thesecomputer-aided systems are in extensive controlof

the paint preparation process: the right colours can be produced in the right amounts, sothere are fewermis-prints and thereis lesswaste.

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TechnicalSurvey

Status of computer-a ided pre-press

process

traditional dyeing/printing

comp.-aided bath/paint compos.

obsolete avopracl.

+


+

Dyeing automation

The on-line measurement of dye-consumption in continuous dyeing processes is a new

technology; first applications were on the market in 1993. The extension of the system

with colour measuring equipment and feed-back to the dye application pad can be con

sidered to be at the technological frontier, although the equipment for this extension is

commercially available.

Status of dyeing automation

process

traditional dyeing & pressing

on-line measurement of dye-cons .

+ on-line meas . of dye-result

+ on-line supply of dye

obsolete avopracl .

+

best pracl . technofrontier

+

+

+

Reuse of paint

Computer-aided systems (software) for the registration and later reuse of paint remain

ders in textile printing provide the opportunity to save on raw materials and costs of dis

posal. These systems are not yet widely applied.

Status of reuse of paint

process


computerised paint database

Inkjet systems

obsolete avo pracl.

+


+

Printing with ink jet systems is an alternative for rotary screen printing, especially when

short runs are required with 'immediate' delivery. The technology offers significant reduc

tions of dye consumption, as well as reductions in energy and waste. The ink jet principle

is relatively well introduced for carpet printing, but for other materials, such as cotton,

synthetics and wool, the application should be considered as more or less 'under devel

opment'. It is expected that the complete diffusion of ink jet technology may take another

ten years, worldwide. (The traditional rotary screen printing technology is applied for two

thirds of the total amount of printed textile.)

307


Status of printing w~h ink jet systems

process


ink jet systems for carpets

ink jet systems for cotton, etc.

obsolete avopract.

+


+

+

Reuse of chemicals by evaporation

Evaporat ion of process liquids and reuse of chemicals and clean water may be attractive

for the textile finishing industry, but research into these processes is still going on.

Status of reuse of chemicals by evaporation

process

discharging of waste water

evaporation of water/reuse of chem.

obsolete avopract.

+


+

Filtering technologies

A situation more or less similar to the previous one, refers to the applicat ion of advanced

filtering technologies . The recovery of certain dye-stuffs or process water by means of

membrane filtering has been proven to be technically feasible, but in most cases not

commercially . Further research is going on.

Status of filtering technolog ies

process

discharging of waste water

membrane filtering of indigo

membrane filtering of other dyes

obsolete avopract.

+

+


+

Replenishment of dye

For the application of dispersed dyes on synthet ics, exper iments are going on to replenish

the process bath after each run, up to about five runs. This technology will result in reduc

tion of dye consumption .

308

Technical Survey

Status of replenishment

process

dyeing without replenishing

with replenishing

obsolete avo pract,

+


+

4.4.2 Reduction of water consumption

Of the many new technologies in textile finishing , two have spec ial capabilities for water

saving , i.e. the vacuum technology and the supercritical CO2 techno logy . In special cases,

combined dyeing baths might be applied also .

Vacuum technology

Vacuum equipment for the reduction of the amounts of water or chemical solut ions in a

wet textile web , is available for about ten years now. Although several hundreds of these

systems have been sold worldwide, the technology can still be cons idered as best prac

tice .

Status of vacuum technology

process

removal of chemicals by washing

washing + drawing by vacuum

obsolete avo pracl.

+

best prado technofrontier

+

Combined dyeing baths

A reduct ion in the number of process baths can be obta ined by dying mixed fabrics

(cotton + synthetics) in one bath with a mixture of dyes.

Status of combined dyeing baths

process

separate baths

combined baths

obsolete avopracl.

+

best prado technofrontier

+

Dyeing with supercritical CO2

The many advantages of dyeing polyester with supercritical CO2 (see sect ion 4.2.3) are

counterbalanced - up till now - by the high costs of the equipment and the limitations in

batch size. However, research is going on, mainly in Germany. Large-scale applications

are not to be expected at short notice.

309


Statusof dyeingwith supercritical CO2

process

traditional dyeingof polyester

dyeingw~h supercritical CO2

obsolete avo pract.

+

bestpracl. technofrontier

+

4.4.3 Reduction of energy consumption

Finally, there are three technologies favouring energy saving, i.e. the use of atomisation,

the dye-application with rollers and vacuum drying.

Atomisation of water or solutions

Equipment for the application of small quantities of liquids (water or chemical solutions) by

means of an atomisation process is available for about ten years now. Several hundreds

of these systems have been sold worldwide; still it is estimated to be a 'best practice'

technology .

Statusof atomisationof wateror solutions

process

submersionin baths

atomisationof water or chemicals

obsolete avopract.

+

bestpract. techno frontier

+

Application of finishing chemicals with rollers

When evenness of chemicals applied to the textile web is not critical, this roller system

can be used. It saves energy in the subsequent drying process because significantly less

liquid (water) is applied in comparison with the submersion process. The system is avail

able for about 15 years now; about 100 of them have been installed worldwide . For the

application of dyes, this technology can be used in certain cases only; experiments are

going on in this field.

Statusof application of finishing chemicals with rollers

process

submersion in baths

application of chemicals with rollers

application of dyes with rollers

obsolete avopract.

+


+

+

Drying with vacuum

Vacuum technologies have been mentioned under heading Vacuum technology, as

means for the reduction of water consumption . It will be clear that the application of this

technology for drying purposes will lead to considerable reduction of energy consumption

too. This is the reason why it is considered here as a separate drying technology .

310

Technical Survey

Status of drying with vacuum

process

drying by pressing + healing

+ drawing by vacuum

obsolete avopract.

+

best pract. techn, frontier

+

Pad/bath systems

In pad/batch processing, fixing of reactive dyes is obtained by storage of the dyed fabric

over a prolonged period of time instead of heating. This leads to energy saving, besides

some reduction in dye consumption .

Status of pad/batch systems

process

fixing by means of heating

id. by means of cold storage

4.5 Actors & factors

obsolete avopract.

+


+

The innovations in the textile finishing industry described in the preceding sections, are

driven by a number of different actors in the production cluster. In this respect we might

distinguish four categories of innovations, that appear to be rather divergent in number of

innovations involved, but, nevertheless , are probably representative for the sector.

In the first place there are the innovations developed by the machine suppliers. This is by

far the largest group, involving 8 of all 15 innovations mentioned; they are summarised

below, including the reference to the previous section:

• Foam printing

• Dyeing automation

• Ink jet systems

• Vacuum technology for removal of chemicals

• Supercritical CO2

• Atomisation

• Dye-application with rollers

• Vacuum technology for drying .

It will be clear that in the case of vacuum technology there is in fact only one innovation,

but the two applications mentioned have important consequences in two different envi

ronmentally relevant areas. For all these innovations it can be said that they combine

several advantages , such as reduction of dye, water and/or energy consumption, increase

of productivity , improved quality control, improved flexibility, etc. The environmental as

pects are only part of the total improvement; economical aspects play also a large part.

For the users, Le. the textile finishing sector, it is easy to see the advantages of these in

novations. In the case of supercritical CO2 there is in fact no innovation yet, because up till

311


now there has been no market introduction. The technology is under development in a few

university and European research projects, supported by machine suppliers.

In the second category of innovations there are four technologies driven by environmental

legislation. These are:

• Reduction of systemcontent

• Improvement of fixingratios

• Reuse of chemicalsby evaporation

• Filtering technologies.

All these innovations focus on the reduction of dyes and other chemicals, by improve

ments at the sources (Reduction of systemcontentand Improvement of fixing ratios) or as

an end-of-pipe technology (Reuse of chemicals by evaporation and Filtering technolo

gies). The reduction of system content is important for the textile printer; the actual devel

opments are done by the machine supplier. The research into better fixing ratios is per

formed by the dye producers. The evaporation process is still in an experimental stage,

driven by textile finishing enterprises, machine suppliers and university research. Mem

brane filtering technologies are also still in an experimental stage as far as the textile fin

ishing sector is concerned, with the same actors as in the development of evaporation

technology .

Innovations of the third category, involving computer-aided pre-press technologies

(Computer-aided pre-press) and reuse of paint (paint database; Reuse of paint), are initi

ated by the dye producers, in co-operat ion with machine suppliers. Both innovations in

volve environmental improvements, but also clear advantages in the economy of produc

tion, including product quality.

In the final category we have only one innovation, i.e. the transfer printing technology

(Transferprinting). Here the textile printers have the lead, pressed by their clients , espe

cially in the fashion products. Environmental aspects are secondary drivers.

4.6 Literature

(Anon.) (1995), Bedrijfsmodel Textielveredelingsindustrie; ECO Management GUide, Imd

Micon

Etman, E.J., MW. van Schijndel, E.R. Socz6 (1994), Verkenning van technologische

oplossingen voor milieuproblemen in de textiel- en tapijtveredeling; rapport nr. 776 101

006, RIVM, Bilthoven

Gels, H.B., D.R. van Veldhuisen (1988), Antimoon in afvalwater van textielveredelingsbedrijven; Rijkswaterstaat (RIZA)/Provincie Utrecht, Lelystad/Utrecht

Heuvelman, E.H., A.J.C.M. Matthijsen (1993), Textielveredeling; SPIN-reeks nr. 773 006

145, RIVM Bilthoven

312

Technical Survey

Journee R , M. Kiekebosch , WJ. Tichelman (1987), /nformatiebunde/ Textie/verwerking,

Ministerie VROM , Den Haag

Koning ter Heege, WJ .M., J.W Klein Wolterink, D.R van Veldhuisen (1992), Omvang en

aard van afva/waterlozingen in de bedrijfstakken textie/veredeling en tapijtindustrie, stand

der techniek en te verwachten financilHe consequenties; Rijkswaterstaat (RIZA), Lelystad

Schrijer, G.J.M. (1996), Notitie textie/veredeling - techn%gische trajecten ; TNO Industrie,

Delft

Textielvereniging KRL, Centrum TNO Textiel, TAUW Infra Consult (1993), Verwijdering

van k/eurstoffen uit specifieke afva/waterstromen van de textielindustrie; Ministerie

VROM, Den Haag

Veldhuisen , D.R van, WJ.M. Koning ter Heege, J.W Klein Wolterink (1993), Het beheer

sen van /ozingen van milieubezwaarlijke stoffen uit de textie/veredeling; Novem, Utrecht

4.7 Appendix: experts and organisations consulted

drs. A. Luiken

G.J.M. Schrijer

TNO Institute of Industrial Technology, Delft

TNO Institute of Industrial Technology , Delft

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Technical Survey

5 Environmental innovations in industrial painting

5.1 Basic processes

5.1.1 Introduction: A variety of processes

Painting processes are applied in many economic sectors, such as:

• ship building (new ships, maintenance, repair; including off-shore)

• construction:

- civil engineering and utilities

- road- and waterworks

- metal construct ions

- transport installations

• industry:

- metal products

- wooden furniture

- automobile production

- automobile repair

- etc.

• private consumers :

- through retailers, supermarkets , etc.

Each of these sectors has its own paint application processes. It was decided to focus on

industrial contractors , i.e. the suppliers of industrial paint services, because of the larger

share of SMEs in this sector. If we thus exclude the construction industry and car finishing

(repair), and focus on small enterprises in industrial painting, we find many firms active in

the coating of metal products. In this study, attention will be paid to the traditional method

of paint application in this sector, i.e. wet paint spraying, and to two relatively modern

paint application technologies for metal products, i.e. cathaphoresis and powder coating.

A significant part of these processes is the muffling process, so this will be described , too.

5.1.2 Sources of environmental emissions

In paint application, three factors determine the amount of hazardous emissions

(Hulskotte et al., 1992), viz.: the type of paint applied, the method of application and the

drying technology.

The type of paint applied most widely in metal product coating is the conventional wet

paint with an organic solvent content of about 40 to 60%. Substitutes with increasing

shares of application are:

• powder coatings

• water-based paints

• ultra-violet and infra-red curing coatings

• medium- and high-solid paints.

315


Of these types of paint, powder coatings and water-based paints are most popular . The

rate of substitution of wet paints by one of the alternatives is determined by costs , the

technical product quality and the demands on the coated products.

The various methods of application diverge widely in so-called efficiency , i.e. the ratio of

the amount of paint actually reaching the intended surfaces and the amount of paint used.

Main methods of paint applicat ion are:

method of applicat ion

brush (hand-held)

normal spray ing

electrostatic spraying - wet paint

dip coating

mechanical roller

electrostatic spray ing powder

electrophoresis (i.e. cathaphoresis)

whirl-sintering (powder)

paint efficiency

high

low

high

medium

medium

medium

high

high

[In this table, the paint effic iency ment ioned refers to the traditional (original) situat ion, l.e. without any measures for effic iency improvement.]

Paint on metal products can be dried by means of various drying technologies, l.e, by an

air flow (normal or elevated temperatures) , by means of UV or IR radiation, of in muffling

furnaces at temperatures of 120-250°C. Costs, drying times and required final hardness of

the coating are the main factors determining the selection of a drying method. Emissions

of solvents or breakdown products are dependent on type of paint, drying technology

(furnace construction, etc.) and drying temperatures.

In the following sections, a brief outline of the traditional wet paint spraying technology will

be given, after which more detailed descriptions of an electrophoretic application method

(in this case : cathaphoresis) as well as the powder coating process will be presented .

5.1.3 Wet paint spraying

In wet paint spraying , two technolog ies can be distinguished : pneumatic spraying and air

less spraying . In pneumatic spraying , the paint is atomised by means of high air pres

sures ; in airless spraying, the paint flow itself is under high pressure .

An import group of hazardous compounds in wet paints are volatile organic solvents and

thinners . With pneumatic spraying, 30 to 50% of the solvent evaporates . The advantage

of airless spraying is that the paints used can have much lower solvent contents , i.e. 30 to

40% instead of 40 to 60% for normal wet paints.

The reduct ion of emission of these organic compounds can be done with end-of-p ipe

technologies or with measures at the source of pollution. For wet paint spraying , the most

316

Technical Survey

important end-of-pipe measure is the use of a water screen along the walls of the spray

cabin. Measures for emission reduction that can be taken at the source of the process

- besides the replacement by solvent-free paints - focus on the reduction of overspray .

Examples are the change-over from conventional pneumatic spraying (50-60% overspray)

to High Volume Low Pressure (HVLP) spraying (20-40% overspray) , and the change-over

from conventional airless spraying (30-50% overspray) to airless electrostatic spraying

(30-35% overspray) .

In most wet paint spraying applications, a muffling furnace is used for drying and harden

ing the coating. For muffling furnaces a number of measures for emission reduction are

available; these will be discussed in section 5.4.5.

5.1.4 Cathaphoresis

Cathaphoresis is a process where a metal part is covered with a thin layer of paint by

means of an electric current. The metal part is submerged in a tank filled with paint, and

connected with an electrical circuit. The electrical current deposits the pigment onto the

metal. The main purpose of this treatment is corrosive protection, because the resulting

pigment layer is too thin to give sufficient mechanical protection. In all cases , the process

provides for the first layer of protective paint on the metal, the primer. Other layers can be

added after this first one, for instance for better mechanical protection.

Characteristics of this process are:

• high corrosive protection

• relatively low costs

• relatively low environmental impact

• paint can be deposited also inside hollowmetal parts

• many different colours are available.

Cathaphoresis is the standard process for corrosive protection in the automobile industry.

The body of the car is treated in the factory itself, the smaller parts are treated by the sup

pliers of these parts or by specialised firms. However, cathaphoresis is used for other

purposes as well. In the latter case, paint shops are among the major players .

Three process steps can be distinguished in cathaphores is: pre-treatment, main process

and muffling. These steps will be described briefly.

Pre-treatment

The metal parts to be coated generally contain oil, grease and dirt particles. These mate

rials have to be removed before coating can take place; the attachment of the pigment is

hindered by a dirty metal surface. The degreasing processes used in cathaphoresis are

completely identical to those used in electroplat ing; at this point we can thus refer to

these. Innovation processes such as the use of various types of membranes and reversed

317


osmos is, etc. are developing at the same rate, and the status of the new technology can

be considered to be the same in both sectors .

After the degreas ing and rinsing stages, the metal parts may undergo treatment with zinc

phosphate, which produces a thin layer of about 3 micrometer thickness as an under

ground layer, for better attachment of the cathaphoresis coating . This zinc phosphate

coating is a substitute of iron phosphate, which was used before. However, the car

manufacturers require zinc now instead of iron, for reasons of better anti-corros ive quality .

From an environmenta l point of view, this change-over from iron to zinc is certain ly notan

improvement.

Another option in this stage - i.e. after degreasing and rinsing - is passivation with chro

mium (Cr-VI) or with a non-metallic alternative (see section 3.4.4).

Main process

The paint bath in cathaphoresis consists of water with an organic pigment and about 2%

organic solvent. There are no heavy metals involved in cathaphoresis. The metal part

leaving the cathaphoresis bath is rinsed with water. In modern processes, the rinsing wa

ter is filtered , and the regained paint is fed back into the main tank. In this way, the effec

tiveness of paint use can be 99% or higher.

The composition of the main bath is carefully controlled during process ing. The ingred i

ents of the bath are supplied in pre-mixed form. In some cases , a lead-containing com

pound might be added to the liquid in the main bath, in order to reduce the risk of oxida

tion. It can be expected that this lead compound is replaced by a less hazardous com

pound in the near future .

Muffling

After the main process , the sticky paint layer has to be hardened in the muffling furnace at

about 180°C. The high temperature produces organ ic breakdown products causing bad

odours if they are discharged into the open air. Newer installat ions are equipped with af

terburners, where the energy thus produced is used for partially heating the muffling fur

nace ; see also section 5.4.5.

5.1.5 Powder coating

Powder coating is a coating process for metal parts only , because the objects to be

coated have to be electrically conductive. In this respect, the process resembles ca

thaphoresis. The metal parts are covered with a dry pigment powder and 'baked' in a muf

fling furnace , for better attachment of the powder.

Powder coat ing is a relatively new process . Its main advantage is the complete absence

of solvents in this applicat ion. There are still some disadvantages, such as the 'orange

318

Technical Survey

peel' effect after coating. Also the brightness of the colours is lower than that of wet

paints, although the pigments are identical. Main applications are for standard or lower

quality products; at present there are very few high quality applications.

Again, there are three process steps.

Pre-treatment

As a first step, the metal parts are cleaned and degreased. This part of the process is

identical to that of the cathaphores is process. In the second step, a zinc phosphate layer

is added, for protection against oxidation. A substitute for the zinc phosphate is a ca

thaphoresis coating (most often with black pigment, i.e. carbon black). Also, both coatings

may be applied, i.e. zinc phosphate andcarbon black. After these primary treatments , the

products are dried at about 130°C.

Main process

In special clean air spray cabins, the metal parts are coated with dry pigment powder. The

powder is electr ically (negatively) charged, and it is applied to the metal parts by means of

a number of spray pistols. Since the metal parts are electrically grounded, the pigment

particles stick to the metal for a short period of time. Immediately after the spraying, the

metal parts are transferred to the muffling furnace and heated to about 180°C. Here, the

powder hardens or melts (depending on the kind of binder applied) and attaches firmly to

the metal.

The pigment powder consists of an organic pigment, available inn many colours. These

pigments are identical to those used in cathaphoresis . For better attachment, as binder is

added; this binder may be a thermo-harden ing polymer (such as an epoxy resin, polyes

ter, poly-urethane) or a thermoplastic polymer, such as nylon.

Muffling

The muffling process for powder coating is the same as the one for cathaphoresis .

Whirl-sintering

Powder coating can be applied also without electrostatic charging of the part to be coated.

In this process, called whirl-sintering, dry pigment powder is stirred by means of a gas

flow within a closed system, whereas the parts to be coated are pre-heated and pulled

through the fluid-like powder. The high temperature of the objects causes the powder to

melt, like in the muffling process. (In practice there is little loss of paint, so this is a favour

able technology for all objects that can stand high temperatures. Applications are known

for products such as elements for central heating systems, frames for bikes and, in gen

eral, simple consumer goods of relatively small size. The technology is not new, but it is

less popular than electrostatic powder coating.) Experiments are going on to find new

319


paints that melt at lower temperatures, so that wood or plastic might also be painted by

whirl-sintering . There is also a trend towards the use of thermosetting plastics as a coat

ing (to replace thermoplastics), for better product protection.

5.2 Technological developments

The main technological and related organisational developments for the paint shop sector

refer to quality management and certification (ISO 9002), perfection of internal and exter

nallogistics, and environmental measures.

The painting services firms follow a general trend among industrial suppliers, in that they

aspire to upgrade their services by further specialisation and co-makership . The paint

shops do not seek to attain a position of main supplier. However, small operations, such

as simple assembly jobs, may be included in their package.

Quality management requires the routine application of numerous product quality tests,

according to international standards. The larger firms have their own laboratories, where

client-specific demands are tried out, where product changes are considered for improved

coating quality, where packaging and transport problems are solved, etc. In this respect,

many incremental innovations, in products and processes, are developed for specific cli

ents or a broader public. The reduction of waste is part of the Zero Defect philosophy as

sociated with total quality.

Internal and external logistics are important means to speed up the production process, to

prevent interruptions - for instance when going from pre-treatment to main process -, to

deliver the products Just In Time at the client's production line, etc. An example is the use

of special containers, where the products to be coated are transported from the client and

back, stored and coated; in this way, the products themselves will never be touched by

anyone of the production personnel.

All relevant product and process innovations are somehow related to environmental is

sues.


As pointed out in section 5.1.2, the type of paint applied most widely in metal product

coating is the conventional wet paint with a high solvent content. The pressure on the

paint industry to decrease the amount of hydrocarbons in paint resulted in the develop

ment of substitutes such as medium- and high-solid coatings, but their adoption is rela

tively slow. Most promising are the powder coating technology and the electrophoretic

application of water-based paints, both described before.

The other main issue in paint development is the reduction of heavy metals, including

copper and zinc, in pigments. Pigments with heavy metals are presently excluded from

the consumer markets. A prohibition has been issued only for cadmium; the change-over

320

Technical Survey

from other heavy metal pigments to - in most cases - organic pigments takes place on a

voluntary basis.

No paint shop can afford refraining from environmental measures. These measures focus

on:

• the prevention of loss of pigments, paint, other chemicals (heavy metals) and energy

• cleaning of waste water

• reduction of organic solvents

• cleaning of waste gases from furnaces

• improvement of paint efficiency.

Specific examples of these measures will be given in the next section. In general, the ap

plication of certain cleaning technologies, including the more sophisticated ones such as

membrane filtering and reversed osmosis, is determined by returns on investments. This

implies that if regaining of materials - paint, pigments - is possible, the introductlon of new

cleaning technologies will often be interesting. To date, levies on the discharge of waste

water and the like are not yet high enough to induce the introduction of the more ad

vanced cleaning technologies .

An actual issue is the position of zinc. Zinc compounds , such as zinc phosphate , are fre

quently used as anti-corrosive coatings. At several places, also in the Netherlands, re

search is going on to find substitutes for zinc. One of the options is the use or organic

materials .

Another issue is the 'de-painting' of equipment and products. In many paint application

processes, especially wet-spraying and powder coating, equipment is clogged with paint;

it thus needs cleaning at regular intervals. Also rejected products might need de-painting .

Several methods of de-painting are available now. The main one is pyrolysis (heating

without oxidation), but heating in whirlbed ovens or chemical methods will also do. The

main problem is the prevention of NO, in the open air.


The technolog ical trajectories to be described in this section deal with a number of the

processes mentioned before. Part of the pre-treatment processes as well as the meas

ures on reduction of rinsing water have been dealt with in chapter 3 of this study, on elec

troplating, but for easy reference they will be repeated here.

5.4.1 Degreasing

Technolog ies for degreasing of metal parts before coating include degreasing by vapour

and by boiling. Within each of these technologies , innovative improvements have been

developed over time. These improvements will be described briefly.

321

Adoptionof EnvironmentBllnnovBtions


Degreasing of metal parts by vapour of boiling halogenated hydrocarbons, such as

trichloro-ethene and perchloro-ethene, has been substituted for the larger part by de

greasing with water-based agents. The use of trichloro-ethene has been prohibited

worldwide , for other halogenated degreasing agents standards for maximum emission

have been set. FUlly closed vapour degreasing systems are available, but they require

high investments , i.e. too high for most smaller enterprises.


Degreasing of metal parts by means of immersion in cold or boiling alkaline solutions is

average practice now. Boiling causes agitation, which improves process quality. A disad

vantage is the loss of liquid, so other means of agitation are applied also, in non-boiling

solutions.

Most degreasing baths contain 'complexes', in order to prevent precipitation of metal

compounds, for instance hydroxides. Examples of complexes are cyanide compounds ,

EDTA and NTA. These are relatively hazardous compounds, so in many cases they have

been substituted by organic compounds, such as acrylates, gluconates and fosfonates. A

disadvantage of all complexes is their destabilising effects on water purification systems.

Therefore, their use should be limited to lowest possible concentrations .

Bath life extension

The increasing costs of disposal of chemical waste have led to the development of tech

nologies for prolonged use of degreasing baths. For prolonged use of baths, it is essential

to avoid accumulation of chemical waste, oil residues, solid particles, etc. The main tech

nologies for prevention of accumulation are:

• skimming of free oil, floating at the surface of the liquid

• removal of emulgated oil, by membrane filters or by means of electro-coalescence .

The filtering technologies are not yet common practice; they are not successful in all

cases, so smaller firms hesitate to implement them.

• cascade baths. The metal products to be degreased pass several baths, whereas a

small counterflow of liquid takes up the larger part of the chemical waste and oil. This

relatively simple technology saves cleaning liquids, and its maintenance costs are low.

In most cases, combinations of these bath life extension technologies are used, because

different chemicals require different cleaning methods.


Government regUlations in the Netherlands (and other European countries) , preventing

pollution of surface waters , have led to water saving production methods in many sectors

of industry , including the paint application industry. Especially the large amounts of rinsing

322

TechnicalSUlYey

water have been tried to reduce. The main technologies for reduction of rinsing water will

be described below. For the paint application sector, they include: prevention of drag, and

the use of rinsing reservoirs and cascade rinsing.

Prevention of drag

Transport of products from one bath to another implies unwanted transport of liquids and

chemicals. Reduction of this 'drag' will reduce the amount of rinsing water needed. The

main methods for drag prevention are:

• dripping and tapping off of the metal parts

• air knife. Feasible only for products with mainly flat surface.

• wiping. A sleeve wipes off the redundant liquid. Feasible for automated processing of

products with relatively flat surfaces.

• addition of chemicals lowering surface tension, for fast drying.

Rinsing reservoirs and cascade rinsing

In rinsing reservoirs - located after the actual degreasing baths - chemicals are accumu

lated, whereas the water - especially after degreasing with boiling solutions - slowly

evaporates . After some time, the reservoir contents can be fed back to the degreasing

bath, which results in less chemical pollution and lower water consumpt ion.

Reduction of water consumption can be obtained also by the use of cascade baths, which

were described in the subparagraph on bath life extension.

5.4.3 Reduction of organic solvents

The main process in cathaphoresis uses a water-based paint with an addition of about 2%

of organic solvent. In the original process, i.e. since about 1980, the solvent content could

be as high as 20%. The gradual reduction of organic additives can be considered as a

technological trajectory.

5.4.4 Reduction of chemicals in waste water

The paint shops' process innovations concerning the reduction of residual chemicals in

waste water (rinsing water) resemble those in the electroplating sector. The trajectory can

be described as follows:

• Discharge of waste water without any cleaning, directly to the sewer (in the Nether

lands up to about 1980).

• Simple, traditional cleaning method, based on the combined chemical processes of

detoxification - precipitation - dehydration (see section 3.9).

• Application of filtering techniques with membranes of various pore size: micro

membrane or ultra-membrane filtering, or even reverses osmosis. These filtering tech

niques are not new. For instance, in the production of drinking water from sea water,

323


membrane technologies have been applied for many years. However, for the industrial

paint application sector, these developments are new. In most cases, membrane fil

tering will be more expensive than traditional discharge, even with a system of levies,

but in anticipation of fully closes systems, membrane filtering is subject to feasibility

studies in the large paint shops now.

5.4.5 Reduction of chemicals in waste gases

An end-of-pipe solution in muffling is the use of an afterburner for the removal of break

down products. The heat from the burner is fed back to the furnace. The main reasons for

afterburning are the reduction of hydrocarbons in the open air and the prevent of bad

odours. There are several types of afterburner solutions (Hulskotte et ai, 1992):

• Thermal afterburning without heat exchange. This method can be applied to existing

furnaces with small exhaust flows. The emission of hydrocarbons as well as odours

decreases with up to 99%.

• Thermal afterburning with heat exchange. Also for existing furnaces. Recuperation of

50-60% of the energy.

• Integrated catalyticafterburning. With this equipment and with hydrocarbon concentra

tions of at least 6g/m3, the afterburning process can provide all energy for the muffling

furnace. Hydrocarbon and odour emissions may decrease to 1 or 2%. This system can

be applied only if the paint does not contain materials affecting the catalyst (heavy

metals, halogens, silicium).

• Another method for reduction of chemicals in exhaust gases is the use of active car

bon. With this method, hydrocarbons can be regained, but a disadvantage is that the

exhaust gases require cleaning before absorption by the carbon. This cleaning proc

ess is relatively complicated and expensive.

• Biofiltration is another method for absorption of hydrocarbons in exhaust gases. The

gases need cleaning and cooling before they can be absorbed by the biofilters. The

method is in an experimental stage.

5.4.6 Improvement of paint efficiency in cathaphoresis

An improvement of paint efficiency in cathaphoresis can be obtained by filtering the rins

ing water of the main process by means of the ultra-membrane technique, and feeding the

regained paint back into the main process bath. In this way, an efficiency of about 99% of

the cathaphoresis paint can be obtained.

5.4.7 Improvement of paint efficiency in wet-spraying

In wet-spraying there is a similar development. In the traditional process, the paint effi

ciency is low, due to a large overspray . Protection against paint dust is obtained by using

a water screen along the walls of the spray cabin. The newest developments involve a

recovery of paint from this water by means of membrane filtering techniques.

324

Technical Survey

5.4.8 Improvement of paint efficiency in powder coating

With powder coating, like in wet-spraying, large amounts of paint are lost due to over

spray. In practice, the efficiency of powder spraying is about 40%. Part of the lost powder

can be recovered by a relatively simple filter system at the exhaust of the spray cabin; this

raises the efficiency to about 80%. A further refinement, with the aid of a so-called cy

clone, may increase this figure to 90-95%. In the cyclone, the paint powder leaving the

spray cabin is precipitated along the walls of the cyclone vessel and fed back into the

paint system. Only the lightest particles cannot be captured in this way; these are dis

posed of as chemical waste. The high efficiency figures of the cyclone system are feasible

only if product series are sufficiently large; it will be clear that frequent colour changes

reduce the paint efficiency.


In this chapter, an overview will be given of the status of the innovative technologies de

scribed in more detail in the previous chapter. The definitions for the various rages are

given in chapter 1 of this report. The information is obtained from experts in the industrial

paint sector. Differences in status may occur over the various EU-countries.

5.5.1 Degreasing

In the previous chapter, two different methods for degreasing of metal products were de

scribed. Apart from these technologies, various measures for the extension of bath life

have been included in this section, because these measures are relatively often applied

with degreasing baths.

Degreas;ng by vapour

Halogenated hydrocarbons were used (and in some place will still be used) in the first

stages of degreasing, in combination with degreasing by boiling and electrofytical de

greasing as a finishing stage. Ultrasonic cleaning with soda or soap solutions can be con

sidered as the main substitute of the hydrocarbon process. Closed systems for vapour

degreasing are best practice now.

325


process

trichloro-ethene

perchloro-ethene; other hydrocarbons

ultrasonicvibrationW. soda or soap solutions

closed systems

obsol.

+

+

avopract.

+


+


Degreasing by cold or boiling alkaline (water-based) solutions is average practice, but the

issue is the application of complexes. Substitution of cyanides, EDTA and NTA by organic

complexes probably is average practice, but in some countries this might not yet be the

case.

process

alkaline solutions

+ hazardouscomplexes (cyanide, etc.)

+ less hazardous(organic)complexes

Decreasing: bath fife extension

obsol.

+

avopract.

+

+


The relatively simple technologies for the removal of oil and other polluting materials are

average practice now. The membrane technologies can be divided into ultramembrane

and micromembrane filtering, depending on the size of the particles to be filtered.

process

no technologies for bath life extension

skimming of oil; cascade baths

membranefiltering

obsol.

+

avopract.

+


+


Most technologies for the reduction of rinsing water are average practice now. The Ma

rangoni knife, developed in the electroplating sector, most probably is not in use in the

paint sector .

Reduction of rinsing water: prevention of drag

The three methods mentioned in the table as average practice will be used in combina

tion, in most cases.

326

~ ..~

process

dripping, tapping

wiping

lowering of surface tension

air knife

obsol. avopract.

+

+

+

TechnicalSUNey


+

Reduction of rinsing water: rinsing reservoirs and cascade rinsing

process

no reservoirs and/or cascade baths

rinsing reservoirs and/or 1- or 2-step cascade baths

3-steps (or more) cascade baths

obsol.

+

avopract.

+


+

5.5.3 Reduction of organic solvents in cathaphoresis

The lowest concentration of organic solvent will be best practice; concentrations up to 10

to 12% are estimated to be average practice.

process

main bath w. high concentration of organic solvent

(up to about 20%)

lower concentrations (minimum about 2%)

obsol.

+

avopract.

+


5.5.4 Reduction of chemicals in waste water

As was pointed out in section 5.4.4, the membrane filtering and reversed osmosis tech

niques are not new in technological respect, but for the purification of waste water in paint

shops they are economically not feasible at the moment.

process

no cleaning of waste water at all

simple cleaning: detoxification - precipitation

dehydrat ion

membrane filtering

reversed osmosis

obsol.

+

avopract.

+


+

+

5.5.5 Reduction of chemicals in waste gases of muffling

The applicat ion of an afterburner for the removal of waste gases of the muffling process is

average practice in the Netherlands . However , in other European countries the after

burner might be best practice .

327


process

waste gases into open air

afterburnerwithout heat exchange

afterburner with heat exchange

hydrocarbon absorption technologies

obsol.

+

avopract.

+

best pract. techno front.

+

+

5.5.6 Improvement of paint efficiency in cathaphoresis

process

no feed-back of paint to main bath

filtering of rinsing water and feed-back of paint

to main bath

obsol. avopract.

+

best pract. techno front.

+

5.5.7 Improvement of paint efficiency in wet-spraying

process

no capture of overspray

application of water screens

filtering of water and feed-back of paint

obsol.

+

avopract.

+


+

5.5.8 Improvement of paint efficiency in powder coating

process

no capture of overspray

simple filler system at exhaust of cabin

use of cyclone and continuous feed-back of powder


obsol.

+

avopract.

+


+

The many small and medium-sized enterprises in the (industrial) paint application sector

have little or no possibilities for innovative research of their own. Most innovations in paint

composition and new areas of application are initiated by the paint industry. Especially the

marketing departments of the paint industry appear to be focused on selling existing,

proven technolog ies; often only the packaging and the brand names are new.

It will be clear that for most paint shops the change-over from conventional wet paint

spraying or dip coating to environmentally more attractive methods, such as powder

coating or cathaphoresis , will be determined by the requirements of their clients. Never

theless, in many situations the application of environmental innovations is decided by the

paint shop itself. In these situations the main factors are savings on raw materials (paint,

water) and reduction of costs of disposal of contaminated water or exhaust gases.

328

Technical Survey

In general, process and product innovations originate from a number of actors:

• The machine and chemicals suppliers react to or anticipate government legislation.

Example: the reduction of the organic solvent concentrat ion in cathaphores is baths.

• The suppliers of chemicals react to or anticipate demands of important clients of the

paint shops. An example is the addition of a lead-compound in the cathaphoresis-bath,

to prevent oxidation. It is in the interest of the client to maintain this component in the

paint bath; it yields better results than any other one. [Yet, it will be replaced by a lead

free compound in the near future, due to government regulation.)

• The paint shops themselves try to fulfil the demands of their clients by buying the re

quired chemicals and processes. The car manufacturers, for instance, control their

suppliers (and the suppliers of the suppliers) by means of periodical audits. The

change-over from iron phosphate to zinc phosphate as a primary coating for the cata

phoresis process was induced by the car manufacturers.

• The paint shops install new cleaning equipment when required by legislation or when

old technologies become economically obsolete. In many situations it is still more prof

itable to discharge the waste water directly to the sewer, but with increasing levies on

contaminated water the introduction of better filtering systems will be considered.

• The branch organisations, in general, are represented in national and international

committees , looking after the sector's interests. In agreement with decisions taken at

national or international level, they stimulate the adoption of environmentally improved

technolog ies, provide for information, are involved in pilot projects, etc.

More specific innovations in the best practice or technological frontier stage have their

own actors. For the present study these are:

• Closed systems in degreas ing processes: These systems are applied in vapour de

greasing with organic solvents. They are developed by the surface treatment equip

ment suppliers, in response to government regulations on (halogenated) hydrocar

bons. Closed systems are applied only by the larger firms, in cases where water-based

degreasing cannot be applied.

• Membrane filtering (and optionally: reversed osmosis) for bath life extension and purifi

cation of waste water: These filtering techniques are available from other sectors, so

their application, if economically feasible, is an initiative of the paint shop.

• Feed-back of paint in cathaphoresis, in wet-spray ing and in powder coating: Again,

these are no new techniques, but it will be decided by the paint shop whether or not to

install the feed-back equipment, depending on return on investments.

Further field research in the industrial paint application sector will provide more specific

information on actors and factors in environmental innovations.

329


5.7 Literature

Doorgeest, T., Environmental regulations in the Netherlands; paper for the 10th Int. PRA

Conf., 12-14November 1990, Copenhagen

Eijssen, P.H.M., H.J. Bos, H.B. Duesmann, P. van der Poel, Produktie van verf; RIVM

rapport 736301128; Bilthoven, 1992

Haverland, B.L., Stimulering van het gebruik van oplosmiddelarme verfsystemen in de

metaalindustrie; 2 delen; Adviescentrum VOM; Bilthoven, 1995

Hulskotte, J.H.J., J.P.M. Ros, Lakken en moffelen van metalen; RIVM rapport 736301116;

Bilthoven, 1992

Kemp, R.P.M., A.A. Olsthoorn, F.H. Oosterhuis, H. Verbruggen, Instrumenten voor de

stimulering van milieutechnologie; Beleidsstudies Technologie Economie nr. 14; Ministerie

van EconomischeZaken, DenHaag, 1991

VVVF(Branch organisation of the Dutch paint industry), Statistieken 1994; Leiden, 1995

5.8 Appendix: Experts and organisations consulted

Prof. Dr. R. van der Linde

Ing.M. Raaff

G.F.M.Verrest

Dr. P. Vink

Drs. A.C. Winkelaar

330

University ofTechnology, EindhovenDSMResins, Zwolle

KRONOS, Rotterdam

L.OA Lak, Tilburg

TNO Coatings, Delft

Vereniging vanVerf- en Drukinktfabrikanten - VVVF, Leiden

Annex I: ENVIS Partner meetings - Springer LINK

Documents

Transcript of Annex I: ENVIS Partner meetings - Springer LINK