Re-Formulation and Cost Optimisation of

One Component PU Foams

Ana Mafalda Félix Brilhante

Dissertação para obtenção do Grau de Mestre em

Engenharia Química

Júri

Presidente: Professor João Carlos Moura Bordado (DEQB)

Orientador: Professor João Carlos Moura Bordado (DEQB)

Mr. Aster de Schrijver (Altachem)

Vogal: Professor António Boavida Correia Diogo (DEMAT)

Outubro de 2008

I

Acknowledgements

I would like to express my gratitude to Mr Aster De Schrijver not only for the opportunity he gave

me to develop my dissertation but also for helping to make this great adventure in my life

possible.

A special thanks to Professor João Bordado for making this work possible and for all the

support given during my last years in Instituto Superior Técnico.

I am also grateful to Cathy De Maertelaere for her availability, work and help.

To the Portuguese community in Gent: it was much easier with you!

To Pi for having made the distance so short.

And with all my love to my family all together for being truly together!

Bedankt. Obrigada.

If you can dream it, you can do it! (Walt Disney)

II

Resumo

O presente trabalho teve como principal objectivo o estudo de espumas de poliuretano de

um componente.

Com a crescente preocupação ambiental surgiu a necessidade de se usarem compostos

cada vez mais amigos do ambiente. O primeiro estudo consistiu em verificar se as formulações

com F134a, um agente de expansão com efeito negativo na camada de ozono, poderiam ser

substituídas por um novo desenvolvido pela Honeywell, o HBA-1, um gás com potencial de

deplecção de azoto zero e baixo potencial de aquecimento global.

A conclusão tirada foi que o gás pode ser substituído mas não sem antes se efectuar uma

reformulação da espuma.

O estudo seguinte foi efectuado pela particularidade de se realizar um teste apenas para

espumas de fixação, o teste da porta. A Soudal propôs uma avaliação entre uma espuma já

disponível no mercado e uma nova.

Dada a pouca informação disponibilizada, nomeadamente em relação à formulação, foram

efectuados testes de comparação podendo apenas concluir-se que a nova espuma obteve

resultados aceitáveis e mesmo superiores em relação à já disponível no mercado. Assim, é

possível substituir pela nova espuma de fixação.

O maior desafio deste trabalho foi relacionar e estudar as propriedades da espuma obtidas,

variáveis de resposta, com as variáveis de controlo disponíveis. A principal conclusão tirada foi

que a mudança numa variável de controlo tem consequência não só na variável de resposta

para a qual se destina mas também nas outras, uma vez que se está a quebrar um balanço

entre os vários reagentes usados. Assim, é necessário fazer um estudo minucioso de modo a

avaliar que reagentes têm de ser mudados em simultâneo para que as propriedades da

espuma melhorem globalmente.

Palavras-chave: espumas de poliuretano de um componente; agente de expansão; ambiente;

teste da porta; variáveis de resposta; variáveis de controlo.

III

Abstract

The main objective of this work was to study one component polyurethane foams.

With the growing environmental concerns, the need to use environmentally friendly

compounds is increasing. The first study consisted in verifying if the formulations with F134a, a

blowing agent with a negative effect on the ozone layer, could be replaced by a new one

developed by Honeywell, the HBA-1, a gas with zero ozone depletion potential and low global

warming potential.

The conclusion was that the gas could be replaced but not before a tuning up of the foam

was made.

The particularity of the following study is that a test was performed only for fixation foams,

the doortest. Soudal proposed an evaluation between a foam that was already available in the

market and a new one.

Due to the scarcity of the information available, in particular regarding the formulation,

comparison tests have been performed and the conclusion is that the new foam produced

acceptable and even better results than the one already available in the market. Therefore, it is

possible to replace it with the new fixation foam.

The biggest challenge of this work was to interconnect and to study the properties of the

foam obtained, the response variables, and the available control variables. The main conclusion

was that the change in one control variable has consequences not only on the response

variable on which it was supposed to act, but also on the others, since it breaks the balance

between the various reagents used. Therefore, a thorough study is necessary to evaluate which

reagents must be simultaneously changed in order to improve the properties of the foam

overall.

Key-words: one component polyurethanes foam; blowing agent; environment; doortest;

response variables; control variables.

IV

Index

Acknowledgements...................................................................................................................... I

Resumo ........................................................................................................................................ II

Abstract ....................................................................................................................................... III

Index ............................................................................................................................................ IV

Index of Figures..........................................................................................................................VI

Index of Tables .........................................................................................................................VIII

Abbreviations...............................................................................................................................X

1. Introduction......................................................................................................................... 1

2. Aim of this study................................................................................................................. 2

3. Literature overview............................................................................................................. 4

3.1. Polyurethanes .............................................................................................................. 4

3.2. Polyurethanes Foams .................................................................................................. 4

3.2.1. Flexible Foam...................................................................................................... 5

3.2.2. Rigid Foams ........................................................................................................ 5

3.2.3. Semi Rigid Foams ............................................................................................... 5

3.3. Basic PU chemistry...................................................................................................... 6

3.4. Chemicals used............................................................................................................ 9

3.4.1. Polyols ................................................................................................................. 9

3.4.2. Diisocyanates .................................................................................................... 10

3.4.3. Chain extenders ................................................................................................ 10

3.4.4. Additives ............................................................................................................ 11

3.5. OCF Foaming Process .............................................................................................. 13

3.6. Production .................................................................................................................. 13

3.6.1. One shot process .............................................................................................. 13

3.6.2. Quasiprepolymer process ................................................................................. 14

3.6.3. Prepolymer process .......................................................................................... 14

4. Materials and Methods..................................................................................................... 16

4.1. Reagents and Additives ............................................................................................. 16

4.2. Methods ..................................................................................................................... 16

4.2.1. Optimisation Process ........................................................................................ 16

4.2.2. OCF Benchmarking [10,18]............................................................................... 18

5. Check new gas HBA-1...................................................................................................... 29

5.1. Set-up......................................................................................................................... 29

5.2. Quick Test Results ..................................................................................................... 30

5.3. Discussion and Conclusion........................................................................................ 31

6. OCF Doorstand Report..................................................................................................... 32

6.1. Renaming of Cans ..................................................................................................... 32

6.2. Quick Test .................................................................................................................. 33

V

6.2.1. Discussion of Quick Test Results...................................................................... 34

6.3. AltaFoam Monitor....................................................................................................... 34

6.3.1. Discussion of AFM Results ............................................................................... 34

6.4. Physical Properties .................................................................................................... 34

6.4.1. Discussion of Physical properties ..................................................................... 35

6.5. Door Test ................................................................................................................... 35

6.6. DimStab ..................................................................................................................... 37

6.6.1. Discussion of dimstab results............................................................................ 38

6.7. Aging test ................................................................................................................... 38

6.7.1. Discussion of aging test results......................................................................... 38

6.8. Conclusion ................................................................................................................. 39

7. Developed work ................................................................................................................ 40

7.1. Re-formulation [13] .................................................................................................... 40

7.1.1. AEB3 Project ..................................................................................................... 40

7.2. Full Test of 6096 AEB3 .............................................................................................. 58

7.2.1. Pictures.............................................................................................................. 58

7.2.2. Physical Tests ................................................................................................... 59

7.2.3. AltaFoam Monitor .............................................................................................. 59

7.2.4. Discussion of results ......................................................................................... 59

7.3. Conclusion ................................................................................................................. 60

7.4. Brief Cost Optimisation [13] ....................................................................................... 62

8. Conclusion ........................................................................................................................ 63

9. References ........................................................................................................................ 64

10. Appendix ....................................................................................................................... 65

10.1. Appendix 1 – Quick Test of HBA1 and F134a formulations ...................................... 65

10.2. Appendix 2 – Quick Test of SoudaFoam Report ....................................................... 67

10.3. Appendix 3 - AFM of SoudaFoam Report.................................................................. 68

10.4. Appendix 4 – Physical tests of SoudaFoam Report .................................................. 73

10.5. Appendix 5 – Quick Test of AEB3 Project ................................................................. 76

10.6. Appendix 6 – Physical Tests of 6096 AEB3 .............................................................. 81

10.7. Appendix 7 – AFM of 6096 AEB3 .............................................................................. 83

VI

Index of Figures

Figure 3.1 - Schematic representation of polyurethanes structure. .............................................. 4

Figure 3.2 – Resonance structure of NCO group.......................................................................... 6

Figure 3.3 – Schematic representation of a urethane formation reaction mechanism. [7] ........... 6

Figure 3.4 – Reaction of an isocyanate with a primary amine giving urea. .................................. 7

Figure 3.5 – Reaction of an isocyanate with water resulting in amine and carbon dioxide. ......... 7

Figure 3.6 – Formation reaction of allophanate. ........................................................................... 8

Figure 3.7 – Formation reaction of biuret. ..................................................................................... 8

Figure 3.8 – Isocyanate reacting with a carboxylic acid resulting in an amide and CO2, with the

formation of an instable anhydride. ...................................................................................... 8

Figure 3.9 – Structure of a polyether polyol synthesized by propylene glycol with propylene

oxide. .................................................................................................................................... 9

Figure 3.10 – Structure of a polyester polyol obtain by condensation of ethylene glycol and

adipic acid........................................................................................................................... 10

Figure 3.11 – Molecular structure of a, 2,4 – toluene diisocyanate and b, 4,4’ –

diphenylmethane diisocyanate. .......................................................................................... 10

Figure 3.12 – Schematic representation of polyurethane chain. [14].......................................... 11

Figure 3.13 – The four stages of OCF foaming process. [10] ..................................................... 13

Figure 3.14 – Scheme of a typical quasiprepolymer foam process. [2] ...................................... 14

Figure 3.15 – Scheme of a typical prepolymer foam system. [14] .............................................. 15

Figure 4.1 – Sequence of a project in MultiSimplex.................................................................... 17

Figure 4.2 – Foam dispense on paper. ....................................................................................... 19

Figure 4.3 – Froth Shrinkage. [13]............................................................................................... 19

Figure 4.4 – Froth Outflow. [13]................................................................................................... 19

Figure 4.5 – Foam presenting curing streaks.............................................................................. 20

Figure 4.6 – Example of base holes............................................................................................ 21

Figure 4.7 – Voids and pin holes in a foam................................................................................. 21

Figure 4.8 – Cell collapse............................................................................................................ 22

Figure 4.9 – Example of dispensing in a mould. ......................................................................... 22

Figure 4.10 – No curing shrinkage, a, versus curing shrinkage, b, in mould. ............................. 23

Figure 4.11 – Block to be tested, compression test and adhesion test, respectively. ................ 24

Figure 4.12 – Shear strength test and mould.............................................................................. 24

Figure 4.13 – AltaFoam Monitor.................................................................................................. 25

Figure 4.14 – DimStab: block and samples before cutting. ........................................................ 26

Figure 4.15 – Set-up of the door test and sensors position. ....................................................... 27

Figure 4.16 – a- Door-closing test, b- Vertical load test, c- Doorstop test. ................................. 28

Figure 6.1 - Cans of SoudaFoam and SoudaFoam Alternative. ................................................. 32

Figure 7.1 – Effect of DMDEE on the response variables. ......................................................... 45

Figure 7.2 – Effect of Niax A1 in the response variables. ........................................................... 45

VII

Figure 7.3 – Effect of DME on the response variables. .............................................................. 49

Figure 7.4 – Effect of NCO on response variables...................................................................... 51

Figure 7.5 – Effect of OHv in response variables........................................................................ 55

Figure 7.6 – Effect of additive on response variables. ................................................................ 57

VIII

Index of Tables

Table 4.1 – Reagents and additives used in this work................................................................ 16

Table 4.2 – Control and Response Variables for MultiSimplex software. ................................... 17

Table 5.1 - Weight parts of each gas in the different formulations.............................................. 29

Table 5.2 – Quick Test Results for F134a Samples and HBA-1 Samples.................................. 30

Table 5.3 – F134a Samples. ....................................................................................................... 30

Table 5.4 – HBA-1 Samples........................................................................................................ 31

Table 5.5 – Results Output Test at 5ºC....................................................................................... 31

Table 6.1 - Altachem number and type of the cans to be tested. ............................................... 32

Table 6.2 – Quick Test Results. .................................................................................................. 33

Table 6.3 – SoudaFoam Samples............................................................................................... 33

Table 6.4 – Results Output Test at 5ºC....................................................................................... 33

Table 6.5 – Results of AFM......................................................................................................... 34

Table 6.6 – Physical properties. .................................................................................................. 35

Table 6.7 – Door closing results.................................................................................................. 36

Table 6.8 – Vertical load test results. .......................................................................................... 36

Table 6.9 – Doorstop test results. ............................................................................................... 36

Table 6.10 – Dimstab results for 5527 foam. .............................................................................. 37

Table 6.11 – Dimstab results for 5528 results............................................................................. 37

Table 6.12 – Aging test results for foam formulation 5527 and 5528. ........................................ 38

Table 7.1 – Part/weight of the polyol blend to make 3864 AEB3................................................ 40

Table 7.2 – Control Variables for 3864 AEB3 project. ................................................................ 41

Table 7.3 – Quick test results for formulation 3864 AEB3. ......................................................... 41

Table 7.4 – Re-formulation of 3864 AEB3. ................................................................................. 43

Table 7.5 – Quick test results for formulations 3883 to 3888 AEB3. .......................................... 44

Table 7.6 – Formulations 3908 and 3910 AEB3. ........................................................................ 46

Table 7.7 – Quick test results of formulations 3908 and 3910 AEB3.......................................... 47

Table 7.8 – Formulations 3960 and 3961 AEB3. ........................................................................ 48

Table 7.9 – Quick test results for 3960 and 3961 formulations................................................... 48

Table 7.10 – Formulation 6003 AEB3. ........................................................................................ 50

Table 7.11 – Quick test results of 6003 AEB3 formulation. ........................................................ 50

Table 7.12 – Formulations 6020 to 6022 AEB3. ......................................................................... 52

Table 7.13 – Quick test results of 6020 to 6022 AEB3 formulations........................................... 52

Table 7.14 – Comparative table between the formulations that originated the best results, 3887

and 6003, and the last ones, 6020-6022. ........................................................................... 53

Table 7.15 – Reported problems in the best formulations until now and the last ones. ............. 53

Table 7.16 – Formulations 6043 and 6044 AEB3. ...................................................................... 54

Table 7.17 – Quick test results of 6043 and 6044 AEB3. ........................................................... 54

Table 7.18 – Formulations 6064, 6065 and 6066 AEB3. ............................................................ 55

IX

Table 7.19 – Quick test results of formulations 6064-6066 AEB3. ............................................. 55

Table 7.20 – Formulations 6082 and 6083 AEB3. ...................................................................... 56

Table 7.21 – Quick test results for 6082 and 6083 formulations................................................. 56

Table 7.22 – Formulations 6096 to 6099 AEB3. ......................................................................... 57

Table 7.23 – Quick test results of 6096 to 6099 AEB3 formulations........................................... 57

Table 7.24 – 6096 AEB3 Samples. ............................................................................................. 58

Table 7.25 – Physical Tests Results. .......................................................................................... 59

Table 7.26 – AltaFoam Monitor Results. ..................................................................................... 59

X

Abbreviations

PU – Polyurethane

OCF – One Component Foam

MDI – Diphenylmethane Diisocyanate

DME – Dimethylether

LPG – Liquefied Petroleum Gas

FCA – Foam Controlling Additives

AFM – Alta Foam Monitor

DimStab – Dimensional Stability

NAC – Non Acceptable

AC – Acceptable

P – Paper

M – Mould

SR – Shaking Rate

SS – Surface Structure

GB – Glass Bubbles

CS – Cell Structure

V&PH – Voids and Pin Holes

BH – Base Holes

CC – Cell Collapse

SBH – Side Base Holes

ODM – Overall Density Mould

1

1. Introduction

It was clear that the nylon or polyamide plastics discovered by W.H. Carothers would

become technically important, first of all as textile fibres and later on, when they became

cheaper, as high-melting thermoplastics for injection moulding. To compete with that, Prof. Otto

Bayer was synthesizing polymer fibers when he developed the first fiber-forming polyurethane

in 1937. So it was discovered that the reaction between aliphatic di-isocyanates and aliphatic

diols (glicols) went smoothly under reflux conditions to build linear polymers of high molecular

weight. Although the melting points of these polyurethanes were a little lower than the nylons,

the new materials could be drawn into high tenacity yarn or used as thermoplastics for injection

moulding. [1,2]

The investigation was widened in scope, and the reactions between aromatic

polyisocyanates and alkyd or polyester resins were studied in detail. This research proved very

fruitful and, in the wartime, German foamed products, coatings, adhesives and even an

elastomer were discovered and gradually came into industrial use. After the war, British and

American intelligence teams reported on these important developments, and in both countries

work began on specialised service applications. [1]

The first commercial applications of polyurethane polymers, for millable elastomers,

coatings and adhesives, were developed between 1945 and 1947, followed in 1953 by flexible

foam and rigid foams in 1957. Since then they have been finding use in an ever-increasing

number of applications and polyurethanes are now all around us, playing a vital role in many

industries – from furniture to footwear, from building to cars production. Polyurethanes appear in

an astonishing variety of forms, making them the most versatile of any family of plastic

materials. [3]

2

2. Aim of this study

Since the viability of polyurethanes as a commercial product in the 1930’s, its industrial

production did not stop growing until today. To accompany this increase in overall production

there was also the need to diversity their range of applications.

Nowadays polyurethane polymers are present in almost all sectors of activity.

This dissertation focuses on polyurethanes foams. The aim of this work is to study one

component polyurethane foams and it is divided into two distinct parts.

The first one consists on foam properties analyses from a comparative in a point of view.

With the growing environmental concerns it is fundamental to develop new additives that

have no impact on the environment. With this in mind Honeywell developed a new blowing

agent, HBA-1. Altachem NV study its effect on formulations that already existed by replacing the

old blowing agent with the new one without re-formulation.

The other study was commissioned by Soudal and consisted in the comparison between an

already existing fixation foam and a new one.

The second part of the work was study the impact of changing some reagents in the final

foam properties.

The major concern was to improve the properties of a specific project not only taking into

account the visual and physical properties but also price competition.

3

Foam is a material, and foaming is a phenomenon. Both involve the presence of a gas phase

encapsulated by a spherical shell dense phase. [4]

4

3. Literature overview

A polymer is a large molecule built by the repetition of small, simple chemical units. In some

cases the repetition is linear, much as a chain is built up from its links. In other cases the chains

are branched or interconnected to form three-dimensional networks. The repeated unit of the

polymer is usually equivalent or nearly equivalent to the monomer, or starting material from

which the polymer is formed. [5]

3.1. Polyurethanes

Polyurethanes form one of the most important classes of synthetic polymers.

The name polyurethane is given to polymers that have urethane linkages in their molecular

structure regardless of the chemical composition of the rest of the chain and not because they

are obtained by polymerisation or the urethane groups are the main constituents. [6] Normally

urethane polymers contain a variety of groups in the polymer chain such as polyether linkages –

relatively flexible, aromatic rings providing a constant stiffening factor, urethane linkages that

contribute to strong intermolecular forces, urea linkages, among others.

Despite the characteristic group being usually called urethane it is also called carbamate.

[7]

The structure of polyurethanes is shown in figure 3.1, where urethane groups alternate with

organic radicals.

R1 O C

O

N

H

R2 N

H

C

O

O **

n

Figure 3.1 - Schematic representation of polyurethanes structure.

3.2. Polyurethanes Foams

Urethane foams occupy only a small percentage of the plastics industry at present, but in

light of the newness of urethanes and the rapid advancement in properties and property

improvement the end-use possibilities and growth for foams have exciting predictions. [8]

Foams are microcellular structures, produced by gas bubbles formed during the

polyurethane polymerisation mixture. The process of bubble formation in polyurethane foams is

called blowing. The blowing reaction is one of several reactions occurring in the final

polyurethane mixture while it is foaming. [2]

5

Polyurethane foams can be classified into two categories: flexible and rigid foams. However

in some cases it is also possible to distinguish semi rigid foam.

3.2.1. Flexible Foam

Linear or slightly branched polyols with relatively high molecular weight yield flexible foams.

Flexible PU foams, in contrast to rigid types, yield open-cell materials that allow free

movement of air throughout the materials when flexed. Flexible foams exhibit excellent sound

absorbing properties, low thermal conductivity, and good resistance to most solvents and

detergents, although some solvents (e.g. acetone and trichloroethylene) cause swelling, from

which the foam recovers unchanged upon drying. In presence of strong acids and alkalis

flexible foams are attacked. [2]

These foams are largely used for cushions, unicellular foams, insulation, and transparent

protective covers for radar (both for ground and air). They are also used in packaging and as

shock absorbers for structural purposes.

3.2.2. Rigid Foams

Rigid urethane foams are recognised as an outstanding material for insulation applications.

They have many desirable properties, such as low thermal conductivity, low density, excellent

dimensional stability, high strength-to-weight ratio, low moisture permeability, and low water

absorption, which make them particularly suitable for application in household refrigerators,

refrigerated trailers, and railroad cars, construction, and industrial insulation. [8]

3.2.3. Semi Rigid Foams

Semi rigid foams are thermoplastic and soften with a moderate increase in temperature.

They form excellent bonds between foamed-in-place and the materials used to form cavities

and are used in the field of insulation. [9]

OCF - One component foam - is a semi rigid foam that is self-expanding and self-adhesive

moisture curing gap filler develop by ICI (Imperial Chemical Industries Ltd) by A. Wooler, O.

Bengson and Aster De Schrijver in 1970. [10]

The OCF is dispensed from a simple pressurized container or aerosol-type and requires no

mechanical or power source. When the valve of the container is opened the contents of the

cylinder emerge from the nozzle as a well-expanded froth, which is easily directed into a gap or

hole. [11]

As it leaves the cylinder, the foam has the consistency of a shaving cream, and it is very

sticky and adheres firmly to most surfaces without any pre-treatment. Adhesion to damp

surfaces is excellent, which is particularly important point in a building site. Once in the gap the

foam expands to about double of its volume. [11]

6

When cured, the foam may be trimmed with a sharp knife and finished by normal plastering,

papering or grouting techniques. It can be recessed on external surfaces to accept a

conventional sealant to provide weather resistance. [11]

3.3. Basic PU chemistry

-N=C=O group is responsible for the unique reactivity of isocyanates, characterized by the great

facility of occurrence of nucleophilic reactions. This group of isocyanates has a high degree of

unsaturation, which makes it highly reactive with a wide range of compounds. In figure 3.2 are

represented the resonance structures of this group.

R N C O R N C O R N C O

Figure 3.2 – Resonance structure of NCO group.

The functional group of isocyanates is extremely reactive with nucleophilic substances,

being the most common reaction the nucleophilic attack to double linkage carbon-nitrogen. [2]

The more important reactions of isocyanates to produce polyurethanes are described

below.

1. Alcohol

The reaction, figure 3.3, between an alcohol and an isocyanate to give a urethane is

exothermic and releases 24 kcal/mol urethane. [12]

R O + C

O

N

R'

R O

H

C

O

N

R'

R O

H

C

O

N R'

O

C

O

N

H

R'

R

H

Figure 3.3 – Schematic representation of a urethane formation reaction mechanism. [7]

7

This process represents the fundamental reaction for all processes in polyurethane and

urethane synthesis.

2. Amines

The primary and secondary amines react easily with isocyanates to origin urea. These

reactions are very fast and normally they don’t need catalysts. [12]

R NCO + R' NH2 R N

H

C

O

N

H

R'

Figure 3.4 – Reaction of an isocyanate with a primary amine giving urea.

This reaction takes particularly importance since hydrogen’s from amine compounds are

more reactive than the hydrogen’s from water and so the two will compete to react with

isocyanates. If too much urea is formed the foam will became more and more rigid.

3. Water

In fabrication of PU foams the reaction of an isocyanate with water is extremely important.

The reaction is fast and involves the formation of an unstable intermediate – carbamic acid. The

intermediate acid breaks down in an amine and CO2.

R NCO + H2O RNH C

O

OH R NH2 + CO2

Figure 3.5 – Reaction of an isocyanate with water resulting in amine and carbon dioxide.

This reaction is an expansion reaction because the diffusion of carbon dioxide into the air

bubbles previously nucleated causes the foam expansion. It is an exothermic reaction that

releases 47 kcal/mol water. [12]

4. Urea and urethanes

The hydrogen from urethane and urea groups can react with NCO to produce allophanate,

figure 3.6, and biuret, figure 3.7. These secondary reactions are much slower than the primary

reactions, due to the lower reactivity of the active hydrogen in ureas and urethanes. [13]

8

R NCO + R'NH C

O

OR'' RNH C

O

N

R'

C

O

OR''

Figure 3.6 – Formation reaction of allophanate.

R NCO + R'NH C

O

NHR'' RNH C

O

N

R'

C

O

NHR''

Figure 3.7 – Formation reaction of biuret.

These reactions occur to a much lesser extent than the primary reactions while the froth is

curing; however their importance must not be underestimated because these reactions also

take place in the aerosol cans, which are responsible for reducing the shelf life of the product.

The formation of allophanates, and particularly biurets, is also responsible for crosslinking and

branching, which has an important effect on the foam properties. [13]

If a reasonable rate of reaction is to be obtained, and if no catalyst is present, these

reactions require high temperatures and higher concentrations than those necessary for the

primary reactions. It is important to note that the reaction with ureas to form biurets occurs more

readily than the reaction with urethanes to give allophanates. [13]

5. Acids

Despite carboxylic acids react with isocyanates, they have low reactivity compared with

alcohols, amines and water. [2]

R NCO + COOH R' RNH C

O

O C

O

R'

RNH C

O

R' + CO2

Figure 3.8 – Isocyanate reacting with a carboxylic acid resulting in an amide and CO2, with the formation

of an instable anhydride.

9

6. Condensation

The isocyanates can also react between them to form dimers or trimers.

The dimerization should be carried out at low temperatures because of its thermal

instability, which explains why the dimerization is limited to the more reactive ones, such as the

aromatic isocyanates. The trimerization is very important commercially especially in the

production of rigid foams. [12]

3.4. Chemicals used

A wide range of raw materials is used in the production of polyurethanes, with

diisocyanates, polyols and chain extenders as the principal ones.

3.4.1. Polyols

The compounds with two or more alcohol function are referred as glycols and polyols and a

great variety of them are used in PU’s fabrication.

The type of polyol defines the physical properties of the final foam. In one component foam,

with built in resilience, it will require some stiffness of the polymer network so that overall rigidity

is imparted to the foam. The polymer properties are primarily met by the degree of crosslinking,

and, in turn, this is achieved by an appropriate choice of both molecular weight and functionality

of the polyol used for coupling with the isocyanate. [13]

The more used polyols in polyurethanes synthesis are polyether polyols and polyester

polyols.

The name polyether polyol is given because this macromolecule has beyond the functional

alcohol groups, functional ether groups, figure 3.9.

They are obtained by the reaction of a simple molecule, named initiator, such as ethylene

glycol, propylene glycol, glycerine with cyclic ether such as propylene, ethylene and butylene

oxides. The most common ones are polyoxypropylene glycol and copolymers of

polyoxypropylene/ethylene glycol. [12,13]

The functionality is dependent on the functionality of the initiator molecule, if it is a diol the

functionality is two, and so on.

HO CH

CH3

CH2 O CH2 CH

CH3

O CH2 CH

CH3

OH

n

Figure 3.9 – Structure of a polyether polyol synthesized by propylene glycol with propylene oxide.

10

The polyester polyols were the first ones used in PU development. Normally they are

obtained by the polycondensation reaction of a diacid with an excess of diol, example given in

figure 3.10. Polyurethanes market has four principal types: polyester polyols aliphatic linear or

slightly branched, polyester polyols aromatic of low molecular weight, used in rigid foams,

polycaprolactones, and polycarbonate polyols. [12]

HO CH2 CH2 O C

O

CH24

C

O

O CH2 CH2 O H

n

Figure 3.10 – Structure of a polyester polyol obtain by condensation of ethylene glycol and adipic acid.

3.4.2. Diisocyanates

By analogy with polyols, the diisocyanates are isocyanates with two functional groups.

According to this, two ends can react allowing polymeric chains formation.

The most widely used isocyanates are toluene diisocyanate (TDI), figure 3.11a,

diphenylmethane diisocyanate (MDI), figure 3.11b, and modifications of these products,

especially “crude” TDI and MDI.

NCO

CH2

NCO

b

NCO

CH3

NCO

a

Figure 3.11 – Molecular structure of a, 2,4 – toluene diisocyanate and b, 4,4’ – diphenylmethane

diisocyanate.

The one that was used in this work is MDI; pure MDI is usually solid at room temperature

given its fusion point of 38ºC. [2]

3.4.3. Chain extenders

In polyurethane synthesis beyond the isocyanate and polyol, a glycol or a diamine with low

molecular weight is used. Despite being a component in a smaller percentage they have an

important role in shaping the final of the properties of polyurethane polymers. They contribute to

the nature and to the quantity of the links between the polymer chains, playing a key role in the

elastic properties of polyurethanes because they are small molecules that allow that multiple

11

molecules diisocyanate are close, causing portions of chain groups with the highest

concentration of urethane.

With the reagents above it’s possible to have an idea of the schematic structure of a chain

of polyurethane, figure 3.12.

Figure 3.12 – Schematic representation of polyurethane chain. [14]

Is it possible to identify different fractions of a chain where one is predominantly the result

obtained by the reaction of diisocyanate with the chain extender and the other the sequence

obtained by the reaction of diisocyanate molecules with polyol.

3.4.4. Additives

A large quantity of chemicals may be added to control or to modify both the reaction of PU

formation and their final properties.

Flame retardants

As all organic materials, polyurethanes burn in the presence of oxygen and with sufficient

heat. The flame-retardants are compounds used to delay ignition and reduce burning speed and

smoke. [12]

The physical state of the polymer is very important; for example, one component foam is a

semi rigid foam that because of its highly cross linkage is less flammable than flexible foams.

[13]

It is possible to reduce flammability of OCF by the use of compounds containing

phosphorous, halogens, boron, sulphur, antimony and various other metals. This reduction is

possible in the case of foams based on reactive flame retardant polyols (involving

reformulation), flame retardant additives (usually considered to be inert) or inorganic additives.

[13]

Silicones

The silicones used are surface active agents and can be classified in two groups depending

on the type of connection involved. If the connection is between the silicone Si and the O of

polyether (Si-O-C) the surfactant is hydrolysable, however if the connection is between the

silicone Si and the C of polyether (Si-C) it is not hydrolysable. [12,13]

Surfactants are molecules with structure characteristics allowing them to combine materials

with different properties. Typically, one component in surfactant has affinity to apolar phase

(hydrophobic) and another has affinity to the polar phase (hydrophilic). [13]

12

The stability of the cells of the froth is greatly influenced by the surface tension of the liquid.

The greater the surface tension, the greater the restraining force against expansion. Not adding

silicone causes froth collapse before the polymer is sufficiently cured. Gas must come out of the

solution quickly, forming a large number of tiny bubbles in the froth. These bubbles are

stabilized by the combined action of surfactants and the increased viscosity and elasticity of the

froth caused by moisture uptake curing. Silicones will lower the surface tension but must also

increase the system’s tear length so in the OCF froth, while curing and expanding, the gas must

be maximum retained in the form of bubbles which ultimately give the maximum closed cell

structure foam [13]

In short, silicones are particularly useful in PU foams having several functions such as

reduction of the surface tension, emulsification of the materials that are incompatible in the

formulation, promotion of nucleation of the air bubbles and stabilization of foam growth, among

others. [12]

Catalysts

Without a catalyst, the isocyanates group reacts slowly with alcohol, water or itself. The

choice of the catalyst on PU is usually made in order to obtain an appropriate profile among the

different reactions that can occur during the manufacturing process.

Besides the fact that catalysts are employed to bring about faster rates of reaction they also

establish a proper balance between the chain-propagating reaction and the foaming reaction. A

balance has to be established between polymer growth and gas formation in order to entrap the

gas efficiently and to develop sufficient strength in the cell walls at the end of the foaming

reaction (evolution of gas) to maintain their structure without shrinkage or collapse. Another

important function of catalysts is to bring about completion of the reactions resulting in an

adequate “cure” of the polymers. [8]

Blowing agents

Polymeric expansion results from the formation of a gaseous compound during

polymerisation. The release of this compound follows the formation of gas bubbles that are held

in cells within the polymer structure, leading to an increase in the overall volume of polymer.

[15]

One way to obtain this expansion is through the reaction of isocyanate with water, which

results in urea and carbon dioxide. The other way is through a physical process: to introduce a

low boiling point liquid that since is an exotermic reaction, evaporates and consequently

promotes the expansion.

Although the reagents described in detail above are the main and most used ones in almost

all formulations of polyurethanes, it is important to note that deeper analysis of the

13

characteristics of foam lead to the necessity to add another type of additives. References to

these will be made throughout the paper where appropriate.

3.5. OCF Foaming Process

OCF foaming process has generally 4 stages.

Figure 3.13 – The four stages of OCF foaming process. [10]

In the first one the aerosol can is filled off with a mixture of polyol blend, isocyanate and

blowing agent. The prepolymerisation reaction occurs inside the can. At dispensing (second

stage), the liquid prepolymer leaves the can and expands immediately to a low-density froth due

to the evaporation of the blowing agent. Once exposed to the air, third stage starts, and the

froth cures by the reaction with moisture in the air or from the substrate, resulting in CO2

production that gives a second expansion of the froth. The final stage consists in low-density

fully cured foam. [10]

3.6. Production

To obtain a polymer with useful properties more than a simple mixture of polyol, isocyanate

and additives is necessary. In reality, there is the need to introduce some changes in order to

obtain, from a simple mix of two components, a polymer with industrial utility.

3.6.1. One shot process

As the name indicates, the components are mixed directly, generally with the simultaneous

addition of auxiliaries such as catalysts, foam stabilizers, reinforced agents, fillers, and fire

retardants. The reaction is highly exothermic and largely completed in 0,5 min to 30 min,

depending upon the catalyst. The final properties, however, are frequently reached only after 24

to 48 h. [16]

There are two ways to do one shot process: the first one is to mix all the components

simultaneously being the urethane polymer produced in one step. The other one consists in

mixing all the components except isocyanate. This approach makes the final mixture simpler,

with only two components. The advantage of simplifying the mixture process is to decrease the

mixing equipment and, in consequence, also the costs. [14]

The one shot process is characterised by the absence of a prepolymer intermediate.

14

3.6.2. Quasiprepolymer process

In this approach, part of the polyol to be used in the formulation is prereacted with all of the

isocyanate. The resultant product is NCO-terminated as in a prepolymer; however, the free

NCO content of the quasiprepolymer is much higher. Foams are prepared by adding water,

catalysts, surfactants, and the remaining polyol. [2]

The quasiprepolymer approach is recommended when the isocyanate of choice is either

solid at normal operating conditions or when a modification will result in improved properties or

processing of the resultant foam. Quasiprepolymers also have been made with polyols or chain

extenders that are difficult to process when used alone. In many applications, the high free

NCO-terminated products are handled as though they were basic isocyanates. [2]

Figure 3.14 is a schematic diagram of the quasiprepolymer method.

Figure 3.14 – Scheme of a typical quasiprepolymer foam process. [2]

3.6.3. Prepolymer process

In the prepolymer foaming process, mostly used for flexible foams, the hydroxyl compound

is reacted with an excess of isocyanate (NCO:OH ratio 2:1) to form an isocyanate-terminated

prepolymer. [2]

15

Figure 3.15 – Scheme of a typical prepolymer foam system. [14]

16

4. Materials and Methods

4.1. Reagents and Additives

The reagents and additives employed in this work are shown in table 4.1.

Table 4.1 – Reagents and additives used in this work.

Type Full name Chemical name/ Specification Funcionality

GP1000 Propyleenoxide/ glycerol 3 Polyol

VD1000 Polypropylene glycol 2

Crosslinkers FCA202

29,2 % voranol CP 1055 polyol

60,1% monopropylene glycol

9,98% saxol 8002

2

Plasticyzer Cereclor S45 Chlorinated paraffin -

Silicone B8870 Polysiloxane-polyether 2

DMDEE 2’-Dimorpholino diethyl ether - Catalyst

Niax A1 70% bis (2-dimethylaminoethyl) ether -

Witco L6164 Cell opener - Additive

OSI L5348 Cell opener -

LPG

Butane 33,5%

Propane 46,5%

Isobutane 20%

- Gases

DME Dimethylether -

4.2. Methods

4.2.1. Optimisation Process

One objective of this work is the tuning up of PU foams and therefore the process of

optimisation is essential. In an environment of increasing international competition where

countries with lower production costs quickly catch up technologically, new thinking is required

in order to meet the competition. A proactive way of meeting the increasing competition is to

focus on maximizing the utilization of existing technology and, faster than the competitors, being

able to continuously introduce and make use of new technology. This means much more than

just investing in new equipment. [17]

The ability to optimise or improve a process is dependent upon the ability to control the

process, which in turn is dependent upon the access to reliable and valid measurements. A

successful industrial optimisation thus entails a strategic approach encompassing the whole

chain: [17]

Measuring => Controlling=> Optimising

17

Experimental optimisation can be carried out in several ways, being the most known the

one-variable-at-the-time approach. This method is, however, extremely inefficient in locating the

true optimum when interaction effects are present. Therefore, since many years ago, a

multivariable experimental design is used in order to overcome such problems.

Sequential designs are very useful for optimisation studies. Experiments are successively

performed in a direction of improvement until the optimum is reached. The simplex approach is

by far the most useful method.

The competitive tool to optimise used in this work was MultiSimplex software. MultiSimplex

is windows-base software for sequential design of experiments and optimisation. This software

handles up to 15 control and response variables simultaneously, it allows maximization,

minimization or a target value for each response variable and it provides an extensive database

with all the experimental results and the suggested trial conditions. The definition of control and

response variables is crucial for the outcome of the optimisation project. The main steps in the

definition sequence are:

Figure 4.1 – Sequence of a project in MultiSimplex.

In table 4.2 the control and response variables for the project are presented.

Table 4.2 – Control and Response Variables for MultiSimplex software.

Project Control Variables Response Variables

Shaking Rate

Cell Structure P 23/23

Base Holes P 23/23

Side Base Holes M 5/5

Cell Structure M 5/5

Overall Density Mould 23/23

AEB3

% Gas

DME

OHv

%NCO

Cereclor S45

B8870 Output

18

In addition to the use of multisimplex new formulations are also obtained by previous experience.

4.2.2. OCF Benchmarking [10,18]

For every sample of foam that is analysed an “OCF Benchmarking sheet” must be filled out.

The OCF Benchmarking sheet is a tool to gather several details about the sample of foam

that is going to be tested, the conditions in which these tests occur and the parameters that will

be analysed for the sample.

Quick Test

Foam properties can be analysed through a Quick Test. This can be applied to the following

foam samples obtained through different dispensing procedures: Foam Bead on Paper and

Foam Bead on Mould.

The foam tested properties are evaluated according to a scale from –5 to 5 (steps of 0,25),

in which the higher the value obtained the better the property.

The foam is dispensed at can temperature but the curing takes place at different

temperature. These temperatures are usually represented by “aerosol can T (ºC)/ curing T (ºC)”.

The foam samples are evaluated at 23/23 ºC and at 5/5 ºC.

The first thing to do in order to fill in the quick test is to shake the can to mix the prepolymer

and the gas inside, giving a score to the shaking rate of the can (the easier to shake the higher

the score). The shaking rate evaluation is very subjective and the score must be given

according to the initial shake, since it becomes more difficult to shake the can as time goes by,

as well as at lower temperatures.

Then the Output Test is carried out . This test consists in dispensing during 10 seconds the

can into a box at maximum tilting of the valve. This must be carried out at 5/5ºC because this is

the worst situation. Then by measuring the mass of the can and the box, before and after

dispensing, it is possible to know Output Liquid (g/s), Output Foam (g/s) and Gas Loss (%).

Afterwards the foam must be dispensed on paper and on mould.

Quick Test on Paper

In order to test the foam on paper it is necessary to prepare a properly identified piece of

paper to test the required samples and the conditions in which the dispensing and curing will

occur.

19

Figure 4.2 – Foam dispense on paper.

During foam dispensing and while the froth is curing it is important to check if the foam

presents froth shrinkage, figure 4.3, which may happen during the first seconds after

dispensing. This phenomenon is seen mostly with gun foams.

After dispensing adapter or gun foam, some short lines must be drawn on one side of the

sample at a distance of 1,5 – 2 cm from it, to later check if the foam presents froth outflow,

figure 4.4.

Figure 4.3 – Froth Shrinkage. [13]

Figure 4.4 – Froth Outflow. [13]

In order to distinguish froth outflow from froth shrinkage it is really important to pay attention

to phase 2.

Phase 3 is the post expansion caused by the reaction of free NCO with humidity producing

CO2 release. This phenomenon is a problem of froth stability or froth stiffness shortly after

dispensing. On the one hand we need a low viscosity prepolymer in the aerosol can to assure a

good output but once the froth is dispensed the froth should be stable and not flow out.

Besides the already mentioned analysed properties, the majority is evaluated only after the

curing of the froth. The curing period is also related to the temperature and relative humidity (%

RH) at which the froth is curing.

Description of how these properties can be evaluated is presented below.

20

- Foam on paper

This property is the last one to be evaluated, even if it is the first of the list, because it

reflects the quality of the tested sample. It can be measured by giving an acceptable or non-

acceptable appreciation according to the scores given to the other foam properties.

- Surface structure

The foam surface structure can be smooth or “frothy” (irregular). Adapter applied foams give

a smoother surface than gun applied foams.

- Cell structure

The cell structure of the foam is related to the size and distribution of the cells in the

sample. These cells must not be very large and should present themselves homogenously

distributed throughout the sample.

- Curing streaks

This property is related to problems during the curing of the froth, which causes the

appearance of coarser cells characterised by their weakness and lack of flexibility (hard zones).

This problem is mostly seen in the centre of the foam, where the curing faces more difficulties

due to the fact that it takes longer for the humidity to penetrate that area.

Figure 4.5 – Foam presenting curing streaks.

- Base holes

Base holes are an important physical phenomenon that occurs when the froth is in contact

with the porous surface and no densification of the contact layer can occur (no pressure

development). This occurrence is due to the fact that high boiling blowing agents like butanes

and iso-butanes are captured into the porous structure of the paper surface.

The evaporation of these gases will cause the appearance of base holes, by dissolving the

fresh froth, on the surface of the foam that is in contact with the porous substrate.

The lower the viscosity of the froth the bigger is the risk of base holes.

The base holes cause a very poor adhesion between the foam and substrate.

21

Figure 4.6 – Example of base holes.

- Glass bubbles

Glass bubbles can be identified by the shiny look of the surface of the foam. They result

from a bad gas combination in the prepolymer and they give poor physical properties to such a

foam layer.

Higher boiling points gases such as butane and iso-butane are dissolving the cells at the

surface of the foam what makes cell coalescence due to the quick evaporation.

Usually glass bubbles are more pronounced at low can temperature and in gun applied

foams.

- Crumbling

This property is related to the presence of friable cells in the foam. The friability can be

evaluated by pressing the foam (after 1h, 2h, and 24h). If the foam presents crumbling by

pressing it, a cracking sound will be noticed. The crumbling is more notorious when the curing

takes place at lower temperatures.

- Voids and Pin Holes

Voids and pin holes (small voids) are created due to “gas pockets” which could not be

homogeneously mixed into the prepolymer by shaking. The better the solubility of the gases in

the prepolymer, the lesser liquid gas pockets exist.

Poor shakability or not enough shaking of cans can cause voids in the foam.

The presence of voids will reduce the physical properties of the foam.

Figure 4.7 – Voids and pin holes in a foam.

- Cell collapse

Cell collapse can be detected by the presence of curing streaks or, in an aggravated

situation, by the presence of large void spaces in the foam. The presence of such formations in

22

the foam weakens its structure. This phenomenon is more critical with foam on mould than with

foam on paper (especially in the middle), since the curing conditions are more severe in the

mould.

This happens because the froth is curing too slowly due to a combination of low humidity

level and/or low temperature and/or too hydrophobic prepolymers and so the silicone surfactant

is losing its stabilization power and cell collapse/ coalescence will occur.

Figure 4.8 – Cell collapse.

Quick Test on Mould

The foam can be dispensed in a horizontal mould. The mould must be covered inside by

paper, figure 4.9.

Figure 4.9 – Example of dispensing in a mould.

After the curing of the bead, its properties can be evaluated and scores are given similarly

to the foam bead on paper. The ones that are specifically related with foam bead in mould are

mentioned next.

- Curing shrinkage / Loose/not loose

This property can be evaluated when the cured foam bead is removed from the horizontal

mould. While removing it, it must be checked if the foam fully fills the compartment or if it is, in

fact, loose. In case the foam is loose, it’s considered to have curing shrinkage.

Curing shrinkage cannot be confused with shrinkage after the foam is fully cured

(dimensional stability).

23

Figure 4.10 – No curing shrinkage, a, versus curing shrinkage, b, in mould.

- Side base holes

In order to check for side base holes it is necessary to detach the excess of paper on each

side of the bead. The presence of side base holes is revealed by the low adhesion between the

foam and the paper caused by the presence of such holes.

- Overall density in the mould

The overall density is an average value of the density of the bead inside the mould (greater

density) and the foam on its surface. Weighing the sample and determining its volume,

discounting the paper attached to the bead and thus calculating an overall density value for the

foam on mould, determines the average value for this property.

Full Test

When the purpose is reached the formulation will be in full testing. This means that the

formulation has acceptable results in the quick test on paper and on mould and so it is

necessary to do different tests to see if the foam is good for it applications.

Some tests that are performed are physical tests, AltaFoam Monitor, dimstab, yield, aging

and when is a fixation foam, the door test.

Physical Tests

Most of the physical testing procedures were developed in 1975 jointly with some 1KPU

producers, raw material suppliers and SKZ (Süddeutsche Kunststoffinstitut in Wurzburg).

Besides foam density, already discussed in the previews section, the physical tests include

foams mechanical properties like compression strength at 10%, maximum adhesion strength

and finally maximum shear strength.

The three tests were performed in an Instron 5544 Machine and performed at 23ºC/ 23ºC.

In order to obtain a more precise value, each foam was tested with three different blocks for

each property.

24

• Compression and Max Adhesion Strength

In the test device, figure 4.11, test samples with both sides attached hardboard are

prepared. The foam between the two hardboards has the dimensions of 5 cm x 5 cm x 3 cm

(thickness).

In compression test a force is applied through a moving installed pressure plate, brought

perpendicular to the hardboard. The 10% of foam compression in the used moulds is equivalent

to 3 mm of compression extension. The propulsion speed was 5 mm/min.

For adhesion the setting is exactly the same as for compression. During the testing, a

traction force over a cross hinge and a specific grip construction must be installed or glued onto

the substrate, so that the test force is perpendicular to the testing adhesive surface foam/

surface of substrate. The testing speed was 2 mm/min till the complete failure.

Figure 4.11 – Block to be tested, compression test and adhesion test, respectively.

• Max shear strength

The test samples are made by foaming and filling of the gap in the test mould, figure 4.12.

Figure 4.12 – Shear strength test and mould.

25

By the compression/shear test, the foam is tested, by means of a moving pressure plate

made out of hard steel.

AltaFoam Monitor [19]

AltaFoam Monitor targets the study of curing of the froth. This monitoring is done through 4

major variables: temperature, height, pressure and curing rate.

The apparatus consists in a mould, a gap where the polyurethane foam will be sprayed,

with the four sensors to measure each one of the properties attached.

The temperature sensor is a thermometer, the height sensor is an optical (infra-red light)

sensor, the pressure sensor is a piezoelectric system, and a curing sensor that consists in an

electric conductivity sensor.

The curing in altafoam monitor is measured by foam dispensed in a mould where no water

is added to the froth bead. In this case the humidity mainly penetrates the froth from the top of

the bead towards the center of the bead. These curing conditions are of course more severe

than on paper and therefore the cells in the center of the foam are coarser or may show curing

streaks or even cell collapse.

The expansion of the froth due to the CO2 production is called the post-expansion. It is

calculated by the difference between the final and the initial height of the foam as a percentage

of the initial height.

At dispensing a temperature drop of ∆T is noticed due to the evaporation of the blowing

agent.

In figure 4.13 it is possible to see an AltaFoam Monitor.

Figure 4.13 – AltaFoam Monitor.

26

DimStab [20]

Dimstab is a test where a sample of the foam is stored at a certain temperature and its

objective is to measure its deformation over time.

To prepare the samples it is necessary to mark on a paper an area of 25 x 35 cm2. Before

spraying there is the need to moister this area with water, to shake the can subsequently and to

apply the first layer of the foam on the rectangle. Then one must moister the top of the foam and

apply the second layer of the foam, and bead direction should be perpendicular to the previous

one. Finally one must moister it again and spray the last layer in the same direction as the first

one.

After 24 hours of dispensing the cake the samples can be cut. The blocks must have 10 x

10 x 3 cm3.

Figure 4.14 – DimStab: block and samples before cutting.

After being cut, the samples must be identified, formulation and temperature of storage, and

measured.

After the first measurement, each sample will be stored at the right temperature: -20ºC,

23ºC and 45ºC. After one week, a measurement per week will be made during 4 weeks. It is

important to notice if the shape of the sample does not change due to any warping that might

happen.

Yield

The definition of the foam yield out of one can has been a major source of confusion and

discussion. Big differences on yield per can have been noticed and depend on the testing

method. In altachem the tests are done at 23ºC and consisted in dispensing different layers of

foam in a box, like in dimstab (perpendicular direction and moister between layers), until the can

is empty. After cured, the foam is measured with a ruler as precisely as possible.

Aging Test

The aging test consists in testing the performance of the foam over time.

27

The cans are stored at 45ºC and dispense every week at 5/5ºC and 23/23ºC. One day at

45ºC is the same as seven days at 23ºC, because high temperatures promote the aging of the

can. The test is performed during 8 weeks, and the last can corresponds to 1 year at 23ºC.

Door Test [21]

When a foam is used as a doorframe fixation before being launched in the market it is

important to check if the door can be used for that propose. Subsequently the door test consists

in measuring the displacement of the door with 4 sensors.

• Set-up of the doorstand

The distance between the concrete and the doorframe is set at 30 mm; this value can be

change by steps of 7,5 mm.

The width of the doorframe and of the concrete is 20 cm and 15 cm, respectively.

An important factor is the surface that is foamed in. Normally 6 dot of a defined surface are

foamed in, in 6 areas of 100 cm2, 150 cm

2, 200 cm

2, 250 cm

2 or 300 cm

2, depending on the

shear strength.

In figure 4.15 the position of the 4 sensors is indicated. This information is important to

assess displacements later.

Figure 4.15 – Set-up of the door test and sensors position.

• Testing

The testing consists in 3 phases: the door closing test, the vertical load test and the

doorstop test.

28

The door-closing test

The door closing test consists in closing the door 10000 times. An adjustable pressure

cylinder that is attached to the door promotes this, figure 4.16a. The door is closed with a force

of 80 Newton (corresponding to 8 kg).

This corresponds to a 32 year door lifecycle, which is closed 6 times per week with a force

of 80 N.

The cycle time of closing lies between 2 and 4 seconds. During the test the displacement is

measured by 4 inductive sensors every 10 seconds and the measurements of the

displacements are only stopped 3 hours after the test is completed.

The vertical load test

During the vertical load test, the door is loaded during 15 minutes with a vertical pressure

cylinder, figure 4.16b, which executes a force of 1000 Newton. The measurement is done in the

same way as the door closing test but here the measurement stops after 3 minutes the test is

completed.

The doorstop test

Finally the doorstop test is performed with the same horizontal pressure cylinder which is

now attached to the other side of the door, in order to open the door against the doorstop, figure

4.16c. The load is increased in 3 phases. During the first phase the door is opened 500 times

with a force of 40 N and the displacement is measured at the 4 sensors. Then the door is

opened 500 times with a force of 80 N, and the test is finalized by opening the door 500 times at

100 N. Between the 3 phases and after the last phase, it is necessary to wait a few minutes and

continue measuring in order to evaluate how the door relaxes.

Figure 4.16 – a- Door-closing test, b- Vertical load test, c- Doorstop test.

29

5. Check new gas HBA-1

As previously mentioned blowing agents have an imperative role in OCF production.

Before ozone-layer destruction by chlorofluorocarbons (CFCs) was recognised, these were

widely used as foam blowing agents, and their low thermal conductivity produced very good

insulating properties. But their significant ozone depletion and relatively high potential global

warming led to the effective banning of CFCs.

The second generation – hydrochlorofluorocarbons (HCFCs) – decreases the ozone

depletion but causes global warming. As a response to the ever great environmental concerns,

producers began to look for a solution that consisted in developing a new low potential global

warming blowing agent for one component foam.

Starting from mid 2009 [22], in Europe, it will be forbidden to use F134a,

hydrochlorofluorcarbon, so Honeywell’s technology has found a good alternative: HBA-1, a new

low potential global warming and zero ozone depletion blowing agent.

This chapter is a small part of this replacement since it studies the effect of changing the

formulations that include F134a gas to HBA-1 without a reformulation.

5.1. Set-up

Four different formulations were used, each one with different amounts of HBA-1 / F134a

mixed with other gases (Propane, Butane, Isobutane and DME), also in different quantities

Table 5.1 - Weight parts of each gas in the different formulations.

2479 2679 2805 2971 3721 3722 3723 3724

LPG 80 45 60 - - 60 45 80

DME - 16,5 20 - - 20 16,5 -

F134a 20 38,5 20 100 - - - -

We

ight

part

s

HBA-1 - - - - 100 20 38,5 20

Propane 30 35 - - - - 35 30

Butane 43 65 - - - - 65 43

LP

G m

ix

Isobutane 27 - 100 - - 100 - 27

The following cans have the same formulation and are therefore comparable:

2479 & 3724 AEB3

2679 & 3723 GWMB2

2805 & 3722 AEFlex

2971 & 3721 GEB3

30

5.2. Quick Test Results

The complete quick test results are shown in appendix 10.1.

The results obtained when dispensing the foam on paper and on mould are summarized in

the tables below.

Table 5.2 – Quick Test Results for F134a Samples and HBA-1 Samples.

2479 2679 2805 2971

23/23 5/5 23/23 5/5 23/23 5/5 23/23 5/5

Paper NAC NAC AC NAC NAC NAC NAC NAC

Mould AC AC NAC NAC AC NAC AC NAC F134a

Samples ODM

(g/L) 29,91 18,22 26,17 23,71

3724 3723 3722 3721

23/23 5/5 23/23 5/5 23/23 5/5 23/23 5/5

Paper NAC NAC NAC NAC NAC NAC NAC NAC

Mould AC NAC NAC NAC AC NAC NAC NAC HBA-1

Samples ODM

(g/L) 30,38 15,51 18,54 -

Table 5.3 – F134a Samples.

Substrate Can/ Cure

2479 2679 2805 2971

23/23

Paper

5/5 No Output

23/23

Mould

5/5 No Output

31

Table 5.4 – HBA-1 Samples.

Substrate Can/ Cure

3724 3723 3722 3721

23/23

Paper

5/5

23/23

Mould

5/5

No Output

Table 5.5 – Results Output Test at 5ºC.

Formulation Output liquid

(g/s) Output foam

(g/s) Gas Loss (%)

2479 13,2 11,8 10,4

2679 12,2 7,1 42,0

2805 13,1 13,1 0,2

2871 1,9 1,8 4,3

3721 No Output

3722 20,0 17,4 12,9

3723 18,9 16,5 12,8

3724 10,5 9,3 11,2

5.3. Discussion and Conclusion

It is important to notice that when only HBA-1 was used as blowing agent, the foam is more

viscous compared to F134a. That is why it was impossible to dispense at 5 ºC.

By analysis and comparison of tables 5.3 and table 5.4, cell collapse and voids & pin holes

are worse with HBA-1, particularly at low temperatures. This could mean that HBA-1, due to

being more viscous, is less soluble that F134a and therefore is negatively affecting the cell

stabilization.

Although it is impossible to see glass bubbles and cell structure in tables 5.3 and 5.4 they

are quite similar in both gases (Appendix 10.1).

At lower amounts, curing streaks tend to occur (Appendix 10.1).

In conclusion, HBA-1 can be used as a blowing agent but it cannot replace F134a without a

retuning of the formulations.

32

6. OCF Doorstand Report

When a company wants to market a new formulation the first thing to be done is an intense

benchmark comparison with already existing formulations.

Soudal, a producer of OCF, proposed to Altachem to run an extensive test on recently

developed foam. As we don’t know the formulation or even the name that will be given to it, it

will be called SoudaFoam Alternative in this text.

This chapter has been included in this thesis both because of one interesting test, the

doortest, and because it includes all the benchmarking tests that have been mentioned in

chapter 4.

6.1. Renaming of Cans

A unique Altachem number will be given to each formulation to simplify reference. This

number will be used along the report to distinguish the supplied cans.

Table 6.1 - Altachem number and type of the cans to be tested.

Altachem Number Type Trade Name Producer

5527 GUN SoudaFoam 1K SOUDAL

5528 GUN SoudaFoam

Alternative 1K SOUDAL

The pictures of the two cans provided can be seen below, figure 6.1.

Figure 6.1 - Cans of SoudaFoam and SoudaFoam Alternative.

33

6.2. Quick Test

In order to evaluate the foams, a quick test was done by spraying paper and the mould, as

seen before, and a score was given by visual evaluation to the most important characteristics of

the foam ranging from – 5, very bad, to + 5, very good. The complete quick test results can be

found in Appendix 10.2.

The summarized results are presented in table 6.2 below.

Table 6.2 – Quick Test Results.

5527 5528

23/23 5/5 23/23 5/5

Paper NAC NAC NAC NAC

Mould NAC NAC NAC NAC

ODM (g/L) 19,1 17,3

Table 6.3 – SoudaFoam Samples.

Substrate Can/

Cure 5527 5528

23/23

Paper

5/5

23/23

Mould

5/5

Table 6.4 – Results Output Test at 5ºC.

Formulation Output liquid

(g/s)

Output foam

(g/s) Gas Loss (%)

5527 19,6 17,6 10,2

5528 11,4 10,6 7,3

34

6.2.1. Discussion of Quick Test Results

Foam 5527 has base holes and side base holes both on paper and in the mould and also

has the additional problem of an evident cell collapse, especially at low temperatures. The

formulation is not known but the collapse can be due to slow curing and is more pronounced

with hydrophobic prepolymers due to loss of stabilization power of the silicone.

Besides the fact that some base holes and voids and pin holes are easily seen in table 6.3,

overall formulation 5528 has better results.

Looking at table 6.4, foam 5527 has a higher output than 5528 but both foams lay well

above the necessary 4,5 g/s limit [22]. So the output in both cases is high enough for standard

gun applications.

6.3. AltaFoam Monitor

In chapter 4 it was seen that with AFM it is possible to study the curing of the froth by

measuring temperature, pressure, post expansion and curing rate.

For each foam, 5 moulds have been sprayed and the temperature and pressure

development was recorded during 8 hours.

The graphs are to be found in Appendix 10.3 and the summarized results in table 6.5.

Table 6.5 – Results of AFM.

Temperature Post

Expansion Pressure Curing

Formulation Tmin (ºC) Tmax (ºC) PE% kPa Alfa

5527 19,1 26,9 -2,9 5,6 77,1

5528 21,3 28,3 1,1 12,3 82,9

Measuring post expansion the meter can be disturbed, for example, if there is no barrier

around the foam, whilst expanding it can fall down the side and cause errors in the readings.

Therefore figures, which were very disperse, have been discarded.

6.3.1. Discussion of AFM Results

Comparing the results for both foams that are shown in table 6.5, one may see that they are

quite similar and that only pressure shows a higher value for 5528 than for 5527.

Looking at post expansion and despite the fact that some values were not taken into

account, it is possible to conclude that these foams do not have a high outflow level.

6.4. Physical Properties

Graphs of physical properties are shown in Appendix 10.4 and the values in table 6.6.

35

Table 6.6 – Physical properties.

Shear Strength Compression

Strength @ 10% Max Adhesion

Elongation @

max Adhesion

kPa kPa kPa %

Typical range [13] > 50 > 100 > 145 > 15

5527 24,6 ± 4,6 24,6 ± 5,2 27,5 ± 3,7 8,9 ± 1

5528 46,5 ± 4,3 25,8 ± 1,3 60,3 ± 7,7 15,2 ± 0,2

6.4.1. Discussion of Physical properties

The results for 5528 are clearly higher than for 5527. The differences are more distinctive in

maximum adhesion and shear strength.

The higher values in maximum adhesion and shear strength are concordant with the results

obtained in the quick test. A better base holes rating due to the effective bigger adhesion

surface produced a better result in those two properties.

The properties of 5528 are closer to the typical range of fixation foams.

6.5. Door Test

The door tests were done with foam 5527 and 5528 at 23/23 and at 5/5 both with a 50% of

relative humidity and with a doorframe that was completely foamed in. Total calculated surface

of the foam area was 0,614 m2. The real surface of the foam is reduced if the side base holes

are increased and this happens mainly with foam 5527.

Although it is possible to observe that the maximum displacement of the foam 5528 was

significantly smaller than that of the foam 5527. This could have been predicted by looking at

the evaluation of the higher number and size of the base holes and side base holes and the

lower physical properties of foam 5527.

Both foams pass the entire test because the maximum displacement of 1 mm is not

reached in any of the tests.

Door closing test results

In this test sensor 2 was the most affected one; this means that the maximum displacement

is highest at the top of the door on the handle side and thus where the door is closed. The

results are poorer when the foams are sprayed out of a can at 5ºC and cured at 5ºC.

The foam 5528 scores better than the 5527, especially at 5/5 the foam 5527 almost reaches

the limit of 1 mm.

36

Table 6.7 – Door closing results.

Foam formulation Temperature

can/cure (ºC)

Maximum

Displacement (mm)

23/23 0,6 5527

5/5 0,9

23/23 < 0,1 5528

5/5 0,25

Vertical load test results

Sensor 1 was the most affected one, which is normal since hanging on the door will affect

the upper hinge the most.

Again the better results of the foam 5528 are more pronounced at 5/5.

Table 6.8 – Vertical load test results.

Foam formulation Temperature

can/cure (ºC)

Maximum

Displacement (mm)

23/23 0,55 5527

5/5 0,90

23/23 0,50 5528

5/5 0,55

Doorstop test results

In the doorstop test the results are inverted: foam 5527 scores better than 5528 and the

sensor that has the biggest displacement is different in both cases. Sensor 2 has the highest

displacement during the test with foam 5527 and sensor 3 has the highest displacement during

the test with the foam 5528.

Table 6.9 – Doorstop test results.

Foam formulation Temperature

can/cure (ºC)

Maximum

Displacement (mm)

23/23 0,40 5527

5/5 0,53

23/23 0,80 5528

5/5 0,60

The two foams pass the doortest when fully foamed in.

Further investigation is possible to determine the minimum foamed surface necessary to

pass the doortest in both temperature conditions.

37

6.6. DimStab

Dimstab test were performed in the two foams available. The foams were cured at 23.

Table 6.10 – Dimstab results for 5527 foam.

Foam formulation Days of

storage

Change

dimensions

Change

height

Change

warping

7 0,46% 1,35% 5,00%

14 0,64% 1,80% 6,52%

21 0,58% 1,64% 5,76% +45°C / 80%RH

28 0,90% 1,67% 5,76%

7 0,37% 0,87% 2,92%

14 0,68% 1,54% 4,41%

21 0,53% 1,57% 5,15% +23°C / 50%RH

28 0,66% 1,37% 3,67%

7 0,61% -0,15% 3,76%

14 1,00% 1,01% 3,76%

21 1,39% 1,50% 3,76% -20°C

28 1,10% 1,54% 3,76%

Table 6.11 – Dimstab results for 5528 results.

Foam formulation Days of

storage

Change

dimensions

Change

height

Change

warping

7 2,57% 5,47% 5,80%

14 2,94% 5,93% 5,80%

21 2,65% 5,67% 6,57% +45°C / 80%RH

28 2,42% 5,73% 6,57%

7 0,59% 1,98% 6,12%

14 1,24% 2,68% 6,12%

21 1,24% 3,76% 6,12% +23°C / 50%RH

28 1,29% 3,71% 6,12%

7 2,26% 2,55% 7,16%

14 2,93% 3,10% 7,95%

21 3,36% 3,31% 8,74% -20°C

28 3,59% 4,37% 8,74%

38

6.6.1. Discussion of dimstab results

For the results of the dimstab to be acceptable it is necessary that the maximum values are

–1% for –20 ºC, 2% for 23 ºC and 4% for 45 ºC. [22]

Looking at the results obtained it is clear that the results for 5528 are worst than for 5527,

especially when the temperature decreases.

Globally the results are not acceptable, in particular when analyzing the warping change.

6.7. Aging test

The aging tests were performed for the last 3 weeks, week 6 (corresponding to 42 weeks at

23ºC), week 7 (49 weeks at 23ºC) and week 8 (56 weeks at 23ºC).

The summarized results can be seen in table 6.12 below.

Table 6.12 – Aging test results for foam formulation 5527 and 5528.

Week 6 @ 45ºC Week 7 @ 45ºC Week 8 @ 45ºC

23/23 5/5 23/23 5/5 23/23 5/5

Paper AC NAC NAC AC AC AC

Mould NAC AC NAC NAC NAC NAC

ODM (g/L) 17,35 16,56 17,32

5527

Output Foam

(g/s) 23,0 23,7 22,2

Paper AC AC AC AC AC AC

Mould AC NAC NAC NAC NAC NAC

ODM (g/L) 16,65 15,22 16,82

5528

Output Foam

(g/s) 13,2 15,8 13,3

6.7.1. Discussion of aging test results

The typical range for the storage life is 12 months when stored at 20ºC. [23]

Comparing table 6.2, quick test results, and table 6.4, output test results, with table 6.12,

aging test results, it is possible to conclude that the storage life is not concordant with what was

expected because an old can should lose some properties and one of the easiest ones to see is

the viscosity that normally increases over time.

It is possible to conclude that the cans can be stored for a year without loosing their

properties.

39

6.8. Conclusion

As previously mentioned in this chapter, the main propose of this study was to compare an

alternative foam with a foam that is already available in the market. However it is also our wish

to understand which are the conclusions that can be drawn from a full benchmarking report.

Since Soudal disclosed so little information about the two formulations to be tested the

conclusions are only qualitative, that is to say, the conclusions are based solely on the results

obtained and are not connected with the chemical properties that are so important in PU foams.

Taking into account that the results for the new foam are better or quite similar, the already

existing foam can be replaced by the new alternative foam, 5528.

40

7. Developed work

In this chapter a re-formulation study of one component PU foam will be described since

this is the main purpose of the present thesis.

7.1. Re-formulation [13]

A re-formulation consists in taking one formulation, analysing its properties and improving

the ones that are not satisfactory by changing the initial formulation. This is tried until the

properties achieved are acceptable.

The foam that will be subject to reformulation in this project is of the economic and B3 type.

An economic foam system is applied and has acceptable properties at 23/23 ºC. Minimum

acceptable results mean that when tested the foam presents no outflow, no curing streaks, no

crumbling and no cell collapse. The flame retardancy parameter classifies the foam as B1, B2

and B3. B3 foam is the most common type due to being the cheaper one although is the less

flame retardant.

Foams are also divided according to the way in which they are applied. Standard applied

foams are the ones with a plastic adapter and tube-based in the do it your self industry. The

other ones are gun applied foams, which means a foam dispensing gun, and are mostly used

for professional purposes. This project is about an adapter applied foam.

To re-formulate the project the foams have been evaluated at 23/23 ºC and 5/5 ºC on paper

and on mould, and scored in a quick test sheet. The best formulations, which means the ones

with better results, gave origin to the ones that followed. Besides having used the multisimplex

software, some formulations were developed by analysing the best results that had been

obtained.

7.1.1. AEB3 Project

The characteristics of the initial trial, 3864 AEB3, are shown in tables 7.1 and 7.2.

Table 7.1 – Part/weight of the polyol blend to make 3864 AEB3.

Component Part/weight

GP1000 70

VD1000 30

FCA202 5,15

Cereclor S45 88

B8870 8,90

DMDEE 1,00

41

Table 7.2 – Control Variables for 3864 AEB3 project.

Formulation % Gas DME (weight

parts) OHv %NCO

3864 AEB3 43 24 174 17,2

Before looking at the quick test results of this initial formulation it is important to notice that

GP1000 and VD1000 have the same part per weight - 70 and 30, respectively - in all the

formulations developed for this project.

Polyols are very important. First of all, because they are the reagents that react with MDI to

originate polyurethane but also because of their influence in polymer properties.

Polyols can vary in equivalent weigth, functionality and the degree of rigidity or flexibility

depend on the different chain units in the polyols. For example typical groups that impart

flexibility to the polymer chain are ester and ether groups.

The functionality of the polyols has a profound effect on the properties of rigid foams. Higher

polyol functionality favours greater heat resistance and dimensional stability. The compressive

strength of the foams increases with increased functionality, while the tensile strength and

elongation tend to decrease.

Diols originate less crosslinking in the foam, which means that the foam is less branching.

Since dimensional stability and friability vary in opposite directions with the OHv of the

polyol, a compromise must be carried out to obtain a balance of properties.

So being the GP1000 a polyol with functionality 3, and VD1000 a polyol with functionality 2,

it is important to balance these two components with the purpose to obtain a foam that is not

very rigid and that has no problems like shrinkage and outflow. The proportion of polyols in this

work is a result of conclusions reached in previous projects.

Besides that, nowadays polyols like GP1000 are the more common flame retardants used.

The full quick test results of this project are shown in Appendix 10.5.

A quick test was done and therefore it is possible to evaluate the foam properties.

Table 7.3 – Quick test results for formulation 3864 AEB3.

3864

23/23 5/5

Paper AC NAC

Mould AC AC

ODM (g/L) 30,0

Output Foam (g/s) 14,2

42

The results are quite good, with acceptable results on mould and on paper at 23/23ºC.

Output foam is also above the limit of 4,5 g/s [18] and ODM is between the typical range for

OCF, that is 25 to 30 g/L [19].

The non-acceptable results at 5/5ºC on paper are due to the bad results in the baseholes

and cell collapse rating.

Baseholes are created due to the evaporation of high boiling point gases that are connected

to low viscosity froth, gas mixtures that are very soluble in the prepolymers and dry porous

materials.

The low viscosity froth is usually linked to a low viscosity prepolymer in the aerosol can.

This can be a result of a lower degree of prepolymerization of the prepolymers, which means a

higher NCO:OH value, or a result of low viscous polyol blends with low viscous MDI that creates

low viscosity prepolymers at the same NCO:OH value. Or it can finally be a result of a low

catalyst level, which leads to less side reactions and also low viscosity in the final prepolymers.

The gas mixtures also influence the baseholes, because when the gas is dispensed, it does

not escape through the paper. At low temperatures this phenomenon increases due to the fact

that the solubility of gas at lower temperature is better than at high temperature.

Dry porous materials are absorbing the foam layer, creating gas pockets and releasing gas

that dissolves the foam and causes the base holes.

Summarizing, a certain viscosity is necessary, that makes the gas less soluble in the foam.

A bad cell collapse rating happens because the froth is curing too slowly and this way the

silicone surfactant loses its stabilization power and causes coalescence of cells.

With this interpretation of the results it is possible to obtain new formulations that try to

improve the foam properties.

43

Table 7.4 – Re-formulation of 3864 AEB3.

3883 3884 3885 3886 3887 3888

FCA202

(part/weight) 5,40 5,61 5,40 5,40 5,40 5,40

Cereclor S45

(part/weight) 89 89 89 89 89 89

B8870

(part/weight) 11,60 13 11,60 11,60 11,60 11,60

DMDEE

(part/weight) 1,00 1,00 1,20 1,40 1,00 1,00

Niax A1 - - - - 0,15 0,30

%Gas 44 44 44 44 44 44

DME (weight

parts) 25 25 25 25 25 25

OHv 173 173 173 173 173 173

% NCO 17,2 17,2 17,2 17,2 17,2 17,2

The only formulation obtained by the Multisimplex software was the first one, 3883. The

other ones were obtained by combining the problems detected with the reagents that should

solve them.

The major differences between the initial formulation on table 7.1 and 7.2, and the following,

on table 7.4, are

• More FCA 202

• More B8870

• More DMDEE

• Addition of a new catalyst, Niax A1

FCA 202 is a low molecular diol and therefore increasing this reagent will result in more

chain fractions with urethanes groups and consequently will give more rigidity to the foam. This

increase will also affect the viscosity of the prepolymer because more OHv results in a more

viscous prepolymer.

The addition of more silicone, B8870, provides a better cell stabilization, which is very

important for cell collapse.

More catalyst, either by increasing the amount of DMDEE or by adding a new catalyst Niax

A1, is essential because this will balance the polymer growth with gas formation. Besides the

fact that more catalyst will influence the reactions rate, it is important to have a certain degree of

prepolymerization.

44

The difference between the two catalysts is that DMDEE is more sterically hindered and so

will only promote the NCO reaction with water, figure 3.5, while Niax A1 will also promote the

reaction with urethanes group, figure 3.6, giving a more reticulate and resistant foam.

The results are shown in table 7.5.

Table 7.5 – Quick test results for formulations 3883 to 3888 AEB3.

3883 3884 3885 3886 3887 3888

23/23 5/5 23/23 5/5 23/23 5/5 23/23 5/5 23/23 5/5 23/23 5/5

Paper NAC NAC NAC NAC NAC NAC NAC NAC NAC AC NAC NAC

Mould AC AC AC AC AC AC NAC AC AC AC NAC AC

ODM (g/L) 24,86 25,08 25,86 25,51 24,83 24,71

Output

Foam (g/s) 20,4 19,3 22,6 21,2 22,1 22,0

Looking at the results table one can easily verify that the results on paper are much poorer

than in the initial trial. In the mould, on the whole, the results are acceptable.

The output foam increases. This means that the viscosity did not increase with the

reformulation carried out, by increasing FCA202 and catalyst. This means that the degree of

prepolymerization achieved with more catalyst is not enough to change the viscosity of the

prepolymer and also the increased quantity of FCA202 is not enough to change this property.

It is therefore essential to look again for the detected problems in foam evaluation.

First of all it is important to notice that the baseholes problem is solved. No foam presents a

low baseholes rating. The increase of rigidity of the foam (FCA202) joined with

prepolymerization degree (catalyst) was enough to improve this property. But cell collapse is still

a problem in these new formulations.

The other problems detected were the bad shaking rate at low temperatures, cell structure

and voids and pin holes.

Shaking rate is related to the viscosity of prepolymers and also to the age of the can. Since

the age of these formulations is the same as the initial one this possibility was excluded. As

seen before, since viscosity does not seems to increased by this reformulations, the problem

could be a result of a bad solubility of gases inside the can.

Cell structure is related to the size and distribution of the cells in the sample. An optimum

cell structure is when it presents fine cells, homogeneously distributed. Normally this property

can be affected by low viscosity and low temperature. However in this case the cell structure in

both temperatures is almost the same but the minimum value for an acceptable result, in this

response variable, is higher at high temperatures and due to that cell structure at 23/23 ºC is not

acceptable.

45

Voids and pin holes are created due to the formation of gas pockets and are intimately

connected with poor shakability or bad solubility of gases.

In order to develop the best new formulations, graphs have been made that compare the

scores given to each response variable that presented bad results.

Figure 7.1 shows the effect of increasing the amount of DMDEE, where 3883 has the lower

value and 3886 the highest one.

Figure 7.1 – Effect of DMDEE on the response variables.

In figure 7.2 it is possible to analyse the effect of adding a new catalyst, Niax A1 instead of

increasing DMDEE. The 3883 formulation has no Niax A1 and 3888 has the highest value.

Figure 7.2 – Effect of Niax A1 in the response variables.

By analysing these two graphs it is possible to see that catalysts have almost no effect in

shaking rate and cell structure. One of the reasons why this happen is because more catalyst

46

affects primarily the rate of the reactions. This means that being both response variables

mostly, although not only, affected by viscosity of prepolymer it is expected that the catalyst has

no influence on them due to not having a direct influence on that property.

Voids and pin holes and cell collapse are clearly affected by catalyst. Besides the rate of the

reaction catalyst establishes a balance between the chain propagating reaction and the foaming

reaction, which means that there has to exist a balance between polymer growth and gas

formation. This equilibrium will be one of the major reasons for the occurrence or not of cell

collapse and voids.

In voids and pin holes when more catalyst is added, poorer results will occur. In paper at

23/23 ºC this is not seen in the case of the formulation that has more catalyst added. This could

be an effect of catalyst together with high temperature.

Cell collapse has no behavior pattern with catalyst but for all conditions (P23, P5, M23) it

seems that the best option is the middle amount of catalyst. Just like in voids and pin holes

perhaps to achieve the necessary balance.

Finally it is possible to conclude that the two catalysts have not very different effects on the

final properties of the foam.

No more graphs were possible to do for the reason that the other changes were made in

more than one control variable. It has to be always kept in mind that although these graphs are

trying to analyse the effect of one control variable in a response variable, they are not

independent of the other control variables, which means that these graphs only have meaning

in the case of this project’s formulations.

Table 7.6 – Formulations 3908 and 3910 AEB3.

3908 3910

FCA202 (part/weight) 5,54 5,46

Cereclor S45 (part/weight) 88 89

B8870 (part/weight) 9,50 12,00

DMDEE (part/weight) 1,00 1,00

Niax A1 - 0,15

%Gas 46 44

DME (weight parts) 25 27

OHv 176 173

% NCO 16,9 17,2

To develop these formulations one of the aspects that was taken into account was that

formulation 3887 presented the best results only with bad cell structure.

47

The reagents that have been changed were:

• FCA 202

• B8870

• % Gas

• DME

• OHv

Occurrence of voids can be minimized by improving the miscibility of gases. One way to do

it is through the use of a solvent, like DME, and the other is increasing the amount of gas that is

present in the formulation by reduction of viscosity.

The presence of DME is also advantageous to achieve a good shaking rate.

One of the functions of silicone is nucleation. This way silicone, which tends to lower the

surface tension of the foam components, will promote early nucleation and fine cells, and thus

improve cell structure. Besides that, cell collapse is still happening probably due to slow curing

rate and it is necessary to increase its quantity to create more surface stabilization and avoid

the coalescence of cells.

OHv is connected with viscosity. Increasing its value will increase the viscosity since the

polyol is more viscous than MDI and therefore a more viscous prepolymer will result. This is

especially important in order to balance the increase of gas.

Results of previous formulations are shown in the table below.

Table 7.7 – Quick test results of formulations 3908 and 3910 AEB3.

3908 3910

23/23 5/5 23/23 5/5

Paper NAC AC AC NAC

Mould NAC NAC NAC NAC

ODM (g/L) 22,19 41,71

Output Foam (g/s) 20,9 19,7

Formulation 3910 presents the worst results due to still very bad cell collapse and the voids’

and pin holes’ rating. However notice that is the only where cell structure problems were solved,

maybe for having the bigger amount of silicone and DME that promote the formation of more

fine cells. Density is also very high for this type of formulations. Since there is no reasonable

explanation, this high value in density could be an error of measure.

Voids and pin holes problems were solved in 3908 formulation.

Cell collapse is still a problem but in the 3908 formulation it was improved on paper.

Through the analysis of the results obtained it is not clear which is the best silicone quantity.

Base holes show up again in formulation 3908; this could be a result of too much gas.

48

Since the problems were the same as those described in the previous pages, new

formulations were developed.

Table 7.8 – Formulations 3960 and 3961 AEB3.

3960 3961

FCA202 (part/weight) 5,54 5,54

Cereclor S45 (part/weight) 88 88

B8870 (part/weight) 9,50 9,50

DMDEE (part/weight) 1,00 1,00

Niax A1 0,25 0,25

%Gas 46 46

DME (weight parts) 25 30

OHv 176 176

% NCO 16,9 16,9

It was decided to try the lower value for the silicone B8870 first, since a higher quantity does

not seem to improve the properties of the foam.

A new approach of cell structure can be made. Combining viscosity and miscibility in

prepolymer influences cell structure. There has to be a certain viscosity, by adding more

catalyst for example, due to the higher number of side reactions that will happen or to the bigger

degree of prepolymerization, but also provides a higher quantity of gas. These two properties

combined have to be balanced to promote the formation of fine cells and not of gas pockets.

Therefore the viscosity must not be so high as to not allow the gas to come out and the gas

must not be so high as to not allow cell stabilization.

Finally for cell collapse the increase of catalyst could be also good because cell collapse

among other things is created by slow curing rate and with catalyst the cure of the froth is faster

and possibly there is no time to cell coalescence.

Table 7.9 shows the results for formulations 3960 and 3961.

Table 7.9 – Quick test results for 3960 and 3961 formulations.

3960 3961

23/23 5/5 23/23 5/5

Paper NAC NAC NAC NAC

Mould NAC NAC NAC NAC

ODM (g/L) 25,02 22,51

Output Foam (g/s) 11,8 23,7

49

No important improvements were noticed. Cell collapse is still the major concern.

The only thing to take attention to is that on mould at 5/5ºC formulation 3960 has serious

problems with voids and pin holes, base holes and cell collapse.

No substantial improvements occur on cell structure.

With the two developed formulations it is possible to see the influence of DME on the

properties of the foam, figure 7.3.

Figure 7.3 – Effect of DME on the response variables.

Figure 7.3 shows that, on the whole, the properties at high temperatures are better with

lower amounts of DME, formulation 3960, and at low temperatures they are better with higher

values, formulation 3961. There are no doubts that solubility of blowing agents is indispensable

to obtain a good foam but is also known that their solubility is greatly influenced by temperature,

it decreases as temperature rises. When the temperature is higher the solubility will be lower,

which means that more gas will be retained in the foam, and so the higher the amount of gas

the higher the probability of more problems occurring.

This conclusion is not verified for low temperatures on paper. On paper the foam is less

protected and so it will be easier for the gas to escape. If the quantity of gas is too high, the

quantity of the other reagents that are included in the formulation may not be the same and do

not balance the quantity of gas that is escaping therefore originating worse problems.

With this graph it is easy to conclude that DME cannot be changed without any change in

the others reagents because it has to be related with them. For example, if the DME quantity is

increased, a better solubility in the prepolymer will take place but if this is not connected with an

increased quantity of silicone there will be no improvements on cell stabilization and then the

properties could worsen specially regarding cell collapse, cell structure, base holes and voids

and pin holes.

50

A new formulation was developed considering that as no new problems appear it will be

assumed that the quantity of silicone is reasonable for the next formulations until some problem

connected with it appears and also that catalyst does not seem to have a significant role in this

project.

Considering again formulation 3908 the role of the viscosity will be analyzed by decreasing

the amount of %NCO.

Table 7.10 – Formulation 6003 AEB3.

6003

FCA202 (part/weight) 5,54

Cereclor S45 (part/weight) 88

B8870 (part/weight) 9,50

DMDEE (part/weight) 1,00

Niax A1 -

%Gas 46

DME (weight parts) 25

OHv 176

% NCO 17,4

Increasing the OHv helped to improve the cell structure in the 3908 formulation.

A bigger NCO value corresponds to a larger free isocyanate and as MDI has a lower

viscosity than polyol blend the higher amount of it will contribute to dilute the prepolymer inside

the can.

This is the same that was done in formulations 3960 and 3961 but in that case the viscosity

was reduced by increasing the amount of DME.

The results are shown in table 7.11.

Table 7.11 – Quick test results of 6003 AEB3 formulation.

6003

23/23 5/5

Paper NAC AC

Mould NAC AC

ODM (g/L) 22,72

Output Foam (g/s) 15,7

So far, this formulation presents the best results of this project that are acceptable at 5/5 ºC.

Cell collapse is the only problem that was detected.

The graph below shows the effect of NCO on the response variables.

51

Figure 7.4 – Effect of NCO on response variables.

A low viscosity in the prepolymer could interfere in the size and distribution of the cells but

also if it is high. By analysing figure 7.4, for these proportions of reagents the better value for

cell structure is the lower viscosity that is the higher value of NCO, formulation 6003. The

conclusion in the case of base holes is the same as in the case of cell structure, because the

lower the viscosity, the easier the gas escapes due to not having time to create gas pockets.

Finally, cell collapse is worse for higher quantities of NCO. This could be explained by the fact

that the viscosity is too low for the amount of silicone that was used.

At this stage it is important to analyse in more detail why in all formulations cell collapse is

the major difficulty to solve in the current project. It is known that, despite the influence of the

other components of foam, silicone has an essential role in this problem. The only formulation

where cell collapse did not take place was in formulation 3887 that was the first one with a small

amount of catalyst.

As seen in chapter 3 a balance has to be established between polymer growth and gas

formation in order to entrap the gas efficiently and to develop sufficient strength in the cell walls

at the end of the foaming reaction to maintain their structure without shrinkage or collapse,

caused by the catalysts. For that reason besides looking for silicone it is essential to look for the

amount of catalyst.

Three new formulations were developed. First by following the conclusions from the

previous formulations, where the viscosity of prepolymer is very important and then taking into

account that viscosity changes cannot be dissociated from the changes in another reagents,

specially catalyst and silicone.

52

Table 7.12 – Formulations 6020 to 6022 AEB3.

6020 6021 6022

FCA202 (part/weight) 5,54 5,54 5,93

Cereclor S45 (part/weight) 88 88 88

B8870 (part/weight) 9,50 9,50 12,00

DMDEE (part/weight) 1,00 1,00 1,00

Niax A1 0,15 0,30 0,30

%Gas 46 46 46

DME (weight parts) 25 25 25

OHv 176 176 176

% NCO 17,4 17,4 17,4

The first two formulations are just an update of 6003 together with 3887, the only

formulation without cell collapse problems with addition of NiaxA1. The 6022 formulation took

into account not only the catalyst but also the fact that efficient froth stabilization is necessary,

which is obtained by adding more silicone and also FCA 202.

Table 7.13 – Quick test results of 6020 to 6022 AEB3 formulations.

6020 6021 6022

23/23 5/5 23/23 5/5 23/23 5/5

Paper NAC NAC NAC NAC NAC NAC

Mould AC NAC AC NAC NAC AC

ODM (g/L) 19,83 23,25 26,11

Output Foam (g/s) 18,1 17,7 16,5

Instead of improving, the results were poorer. Cell collapse became worse, especially on

paper and at 5/5 ºC. Increasing the quantity of catalyst alone doesn’t improve the properties of

the foam but also changing more than one reagent without any study is not a good solution. The

changes must be logical and interconnected.

In this stage of the work developed, one of the main conclusions is that when changes are

made in one reagent they will have an impact on the other ones since the existing equilibrium is

broken. And this is the major concern when carrying out a tuning up of OCF foams. The

problems and the reagents are not independent of each other.

In order to try to organize the findings a comparative table - table 7.14 – was created

between the formulations that originated the best scores until now, 3887 and 6003, and the last

ones.

53

Table 7.14 – Comparative table between the formulations that originated the best results, 3887 and 6003,

and the last ones, 6020-6022.

3887 6003 6020 6021 6022

FCA202

(part/weight) 5,40 5,54 5,54 5,54 5,93

Cereclor S45

(part/weight) 89 88 88 88 88

B8870

(part/weight) 11,60 9,50 9,50 9,50 12,00

DMDEE

(part/weight) 1,00 1,00 1,00 1,00 1,00

Niax A1 0,15 - 0,15 0,30 0,30

%Gas 44 46 46 46 46

DME (weight

parts) 25 25 25 25 25

OHv 173 176 176 176 176

% NCO 17,2 17,4 17,4 17,4 17,4

Table 7.15 – Reported problems in the best formulations until now and the last ones.

3887 6003 6020 6021 6022

Cell structure

P23 Cell collapse 23

- Cell collapse P

- Baseholes M5

- Cell collapse P

- Baseholes M5

- Cell collapse P

- Cell structure &

cell collapse

M23

Analysing the 3887 and the 6003 formulations and their problems it is clear that a

connection must be established between silicone, catalyst and gas.

Taking a look at formulation 6020 and 6021 and their problems, it is clear that if cell

collapse remains and if a new problem - base holes - appears when more catalyst is added a

change in B8870 and in gas is required because of the occurrence of a not very good froth

stabilization and a good solubility of gases.

54

Table 7.16 – Formulations 6043 and 6044 AEB3.

6043 6044

FCA202 (part/weight) 5,93 5,93

Cereclor S45 (part/weight) 88 88

B8870 (part/weight) 12,00 12,00

DMDEE (part/weight) 1,00 1,00

Niax A1 0,30 0,30

%Gas 46 46

DME (weight parts) 30 40

OHv 176 176

% NCO 17,1 17,1

Decreasing the NCO amount causes a more viscous prepolymer that should be adjusted by

adding more DME in order not to lose the solubility of the gases inside the can. For this to work

properly it is indispensable to promote good froth stabilization by adding more silicone.

The results achieved with these formulations are shown in table 7.17.

Table 7.17 – Quick test results of 6043 and 6044 AEB3.

6043 6044

23/23 5/5 23/23 5/5

Paper AC NAC NAC NAC

Mould AC NAC NAC NAC

ODM (g/L) 33,05 31,52

Output Foam (g/s) 24,3 31,6

The output test indicates that the quantity of DME in the 6044 formulation was too high and

did not improve the properties of the foam. Actually the results are worse than those of the 6043

formulation. Therefore, and analysing figure 7.3, the conclusion is that higher amounts of DME

are not always the best option to increase solubility and decrease viscosity of prepolymer

particularly if not connected with the other reagents.

The reported problems in the 6043 formulation are voids and pin holes and cell collapse at

5/5 ºC.

Since almost everything had already been tried, a new approach to the problem was

deemed necessary.

And what if the viscosity is too low and does not allow good froth stabilization over the

curing time? If this is true the rapid outgoing of the gas causes more cell coalescence since the

silicone effect has no time to stabilize the froth correctly and as a consequence cell collapse

and voids will occur.

55

When changing the OHv by adding more FCA 202 it is possible to increase viscosity and to

develop new formulations.

Table 7.18 – Formulations 6064, 6065 and 6066 AEB3.

6064 6065 6066

FCA202 (part/weight) 6,55 7,34 8,15

Cereclor S45 (part/weight) 88 88 88

B8870 (part/weight) 12,00 12,00 12,00

DMDEE (part/weight) 1,00 1,00 1,00

Niax A1 0,30 0,30 0,30

%Gas 46 46 46

DME (weight parts) 30 30 30

OHv 180 185 190

% NCO 17,1 17,1 17,1

The summarised results are shown in table 7.19.

Table 7.19 – Quick test results of formulations 6064-6066 AEB3.

6064 6065 6066

23/23 5/5 23/23 5/5 23/23 5/5

Paper NAC NAC NAC NAC NAC NAC

Mould AC NAC NAC NAC AC AC

ODM (g/L) 28,18 29,17 26,24

Output Foam (g/s) 21,6 21,3 22,3

A graph was then created - figure 7.5 – in order to analyse the behaviour of properties of

the foams with the quantity of OHv.

Figure 7.5 – Effect of OHv in response variables.

56

No big conclusions can be reached from figure 7.5 but 6066 shows the best results. The

only remaining problem is cell collapse on paper.

Still thinking that the high solubility and viscosity of the prepolymer can promote more

coalescence of the cells than it was thought and since the OHv was already modified to elevate

the viscosity, a decrease in the DME value was tried in order to obtain a lower solubility of the

gas - tables 7.20 and 7.21.

Table 7.20 – Formulations 6082 and 6083 AEB3.

6082 6083

FCA202 (part/weight) 8,15 8,15

Cereclor S45 (part/weight) 88 88

B8870 (part/weight) 12,00 12,00

DMDEE (part/weight) 1,00 1,00

Niax A1 0,30 0,30

%Gas 46 46

DME (weight parts) 25 20

OHv 190 190

% NCO 17,1 17,1

Table 7.21 – Quick test results for 6082 and 6083 formulations.

6082 6083

23/23 5/5 23/23 5/5

Paper NAC NAC AC NAC

Mould AC AC AC NAC

ODM (g/L) 24,90 25,46

Output Foam (g/s) 14,5 10,2

The results obtained in the 6082 formulation were similar to the results of the 6066

formulation. This means that lowering the amount of DME has not a pronounced effect on the

final properties of the foam but nevertheless there has been some improvement in cell collapse

and therefore this will be the amount used for the formulations that follow.

In 6083, besides cell collapse, bad shaking rate at low temperatures and side base holes

appear again, which means that the increase in viscosity and the decrease in solubility were too

high. This is clear when looking at the output value that is smaller.

Until now adding different additives besides the “typical” ones had never been considered.

After some research a new generation of foam additives combining cell stabilization and cell

opening properties was found to exist. Open cell are needed to improve the dimensional

stability of low-density foams.

57

The additives used were Witco L6164 and Osi L5348.

Table 7.22 – Formulations 6096 to 6099 AEB3.

6096 6097 6098 6099

FCA202 (part/weight) 8,15 8,15 8,15 8,15

Cereclor S45 (part/weight) 88 88 88 88

B8870 (part/weight) 12,00 12,00 12,00 12,00

DMDEE (part/weight) 1,00 1,00 1,00 1,00

Niax A1 0,30 0,30 0,30 0,30

Additive 0,15

(Witco L6164)

0,30

(Witco L6164)

0,15

(Osi L5348)

0,30

(Osi L5348)

%Gas 46 46 46 46

DME (weight parts) 25 25 25 25

OHv 190 190 190 190

% NCO 17,1 17,1 17,1 17,1

Table 7.23 – Quick test results of 6096 to 6099 AEB3 formulations.

6096 6097 6098 6099

23/23 5/5 23/23 5/5 23/23 5/5 23/23 5/5

Paper AC NAC NAC NAC NAC NAC NAC NAC

Mould AC AC NAC NAC AC AC AC NAC

ODM (g/L) 24,56 28,45 25,13 23,45

Output Foam

(g/s) 9,5 8,8 14,1 10,9

The graph below shows the effect of the two additives for two different quantities.

Figure 7.6 – Effect of additive on response variables.

58

In general the best results are obtained in the case of the ones that have lower amount of

additive, 6096 (Witco L6164) and 6098 (Osi L5348).

At the end of these formulations it will be assumed that no more improvements are possible

in this project. The best results obtained correspond to 6096 AEB3 formulation, they are even

better than those obtained in the initial formulation 3864 because it only presents cell collapse

on paper at 5/5ºC.

At the end of this re-formulation work, it is important to notice that the change made in

Cereclor S45, a plasticizer, was not analysed because it was too small. But this reagent plays

an important role in the formulation, which should not be underestimated. Plasticizers make the

prepolymers components more compatible and it is also them that open the space between the

molecular chains and thus help the water to react easier with the NCO groups to form polyurea

linkages. Plasticizer reduces tensile elongation and tear strengths and increases the density

and softens the foam.

In order to verify whether this formulation was acceptable within the OCF parameters a full

test was performed.

7.2. Full Test of 6096 AEB3

Because this was started in the final period of training it was not possible to perform all the

tests that are included in a full test. Therefore only the values for the tests that were completed

are shown.

7.2.1. Pictures

Table 7.24 – 6096 AEB3 Samples.

Substrate Can/

Cure 6096

23/23

Paper

5/5

59

23/23

Mould

5/5

7.2.2. Physical Tests

The full results are shown in Appendix 10.6.

Table 7.25 – Physical Tests Results.

Shear Strength Compression

Strength @ 10% Max Adhesion

Elongation @

max Adhesion

kPa kPa kPa %

Typical range [23] 22 – 50 33 – 120 85 – 150 8 – 20

6096 79,07 ± 2,56 33,70 ± 1,60 66,76 ± 1,35 10,33 ± 1,64

7.2.3. AltaFoam Monitor

The full results are shown in Appendix 10.7.

Table 7.26 – AltaFoam Monitor Results.

Temperature Post

Expansion Pressure Curing

Formulation Tmin (ºC) Tmax (ºC) PE% kPa Alfa

6096 18,39 28,33 58,40 19,76 61,34

The post-expansion measure has the same problem that was presented in chapter 6.

7.2.4. Discussion of results

The density and output rate are 24,56 g/L and 9,5 g/s, respectively, are between the typical

values for one component foams that are, as seen before, for density among 25 and 30 g/L and

for output rate the minimum required is 4,5 g/s.

60

The pictures on table 7.24 show a good foam especially on mould. Looking at the

correspondent picture, the cell collapse on paper at 5/5 ºC becomes clear.

Analysing the results of the physical tests on table 7.25, the values are quite good although

shear strength is bigger than necessary and adhesion is lower than it should be.

7.3. Conclusion

At the end of this chapter it is possible to reach some conclusions about the effect of the

reagents as well as about some combinations that can to be done in order to improve the

properties of the foam.

The effect of the most used reagents is described below.

The Polyols used are a combination of a triol with a diol; the purpose of combining these

two reagents is to obtain a foam that is not very rigid and that has no problems like shrinkage

and outflow. The triol used, GP1000, is also the flame retardant additive.

FCA 202, a low molecular diol, is responsible for the chain fractions with urethanes groups

and therefore increasing its quantity results in a more rigid foam. This will also affect viscosity

since more OHv results in more viscosity due to the fact that polyol is more viscous than MDI;

and obviously more MDI results in less viscous polymers.

Catalysts are essential to balance the polymer growth with gas formation.

Gases increase the miscibility of the gases by reducing the viscosity.

Silicone has a stabilization function because it tends to lower the surface tension of the

foam components and promotes early nucleation and fine cells.

Plasticizers make the prepolymers components more compatible and it is also them that

open the space between the molecular chains. Plasticizer reduces tensile elongation and tear

strengths, increases the density and softens the foam.

The main problems detected were baseholes, cell collapse, bad shaking rate, poor cell

structure and voids and pin holes.

Baseholes occur due to the evaporation of high boiling point gases. To solve this problem a

certain degree of prepolymerization resulting in a given viscosity is necessary, so that the gas

becomes less soluble in the foam.

Cell collapse occurs because the froth is curing too slow and silicone is loosing its

stabilization power. Therefore a combination between catalyst and silicone must be done in

order to guarantee a certain curing rate but also enough sufficient silicone to have stabilization

power during the curing.

Shaking rate is related to the viscosity of prepolymers and also to the age of the can. The

best way to achieve a good shaking rate is to obtain a balance of the viscosity and the solubility

in the prepolymer, that means it must not be too high neither too low.

61

Cell structure is related to the size and distribution of the cells in the sample. Usually this

property can be affected by low viscosity and low temperature.

Voids and pin holes occur due to the formation of gas pockets and are intimately connected

with poor shakability or bad solubility of gases.

Summing up, in order to obtain acceptable results on these properties it is necessary to look

mainly for viscosity, rigidity and miscibility of prepolymers. They should be correlated in the most

correct way so that the resulting polymer is neither too viscous nor too soluble.

Some of the conclusions that were drawn in this work were based on the graphs made.

These graphs show a relationship between some reagents and the final properties of the foam.

Catalysts have almost no effect in shaking rate and cell structure. One of the reasons why

this happens is because more catalyst affects primarily the rate of the reactions. This means

that being both response variables mostly, although not only, affected by the viscosity of the

prepolymer it is expected that the catalyst has no influence on them due to not having a direct

influence on that property. Voids and pin holes and cell collapse are clearly affected by catalyst

because these two properties are an effect of the balance between polymer growth and gas

formation.

The properties at high temperatures are better with lower amounts of DME and at low

temperatures they are better with higher values. When the temperature is higher the solubility

will be lower, which means that more gas will be retained in the foam, and so the higher the

amount of gas the higher the probability of more problems occurring. This conclusion is not

verified in the case of low temperatures on paper. On paper the foam is less protected and

therefore it will be easier for the gas to escape.

If the DME quantity is increased, a better solubility in the prepolymer will take place but if

this is not connected with an increased quantity of silicone there will be no improvements on cell

stabilization and then the properties could worsen specially regarding cell collapse, cell

structure, base holes and voids and pin holes.

Low viscosity in the prepolymer could interfere with the size and distribution of the cells but

also if it is high. The viscosity is too high for the amount of silicone that was used. The lower the

viscosity, the easier the gas escapes, not having time to create gas pockets.

Output rate is a good measure of the viscosity and solubility. If it is high it shows that there

is a great amount of gases in the prepolymer or that the viscosity is too low.

It is also useful to know that if the properties do not improve there are different new

additives that are not often used but that contribute to improve the foam properties. These foam

additives are mostly used to combine cell stabilization and cell opening properties.

The main conclusion of this part of the chapter is that in order to improve a property by

changing one reagent, the effect it will have on others must be taken into account because what

may be a benefit to one of them may be not a benefit to another.

62

Therefore a compromise between the various reagents must be reached in order to obtain

satisfactory properties.

As mentioned before, when the tuning up of a project is carried out it is essential to analyse

the problems that are detected. When there are only a few properties with bad results instead of

using the multisimplex software it is more convenient to change the different parameters without

that tool, and resort mainly to the experience obtained in other projects. When there are too

many parameters to control, the interpretation becomes very difficult and in this case

multisimplex is a very useful tool. In the AEB3 project almost all formulations have been

developed without the use of the multisimplex software.

The result of this re-formulation work was the 6096 AEB3 formulation. It was only possible

to make a few tests and the conclusion is that quite good results were obtained. Only adhesion

could be improved because the value for filling foam was lower than it was expected.

A final remark is done about this project because the first formulation 3864 AEB3 has no big

different results of the final formulation, 6096 AEB3. Therefore a suggestion is that when a foam

just presents one problem maybe is more advantageous to do the full test before do a

reformulation work because that foam could have already enough good properties for the

expected purpose. This way it is save time and money.

7.4. Brief Cost Optimisation [13]

Why talk about cost optimisation when a re-formulation is being developed? One of the

words that can summarize one component foam is “economical”.

Due to the severe price competition amongst OCF producers, more and more low density

foams are being produced that yield more litters of foam per aerosol can.

In addition and also thinking about price competition, higher amounts of low cost non

reactive fillers are added to the foam, that further decrease its physical properties. In such a

way that the physical properties of all OCF systems containing a high amount of low cost non

reactive fillers and a low foam density are so low that the minimum needed as a foamable

adhesive gap filler is no longer assured and fulfilled.

Therefore it is important to develop cost optimisation solutions in order to be competitive in

the market but it is also important to achieve the minimum requirements for the foam

applications. Otherwise poor foam properties can lead to big complaints due to foam failures,

which in the short term could become more expensive than if it reformulations were made that

take into account not only the price but also the minimum requirements for a filling or fixation

foam.

63

8. Conclusion

Polyurethanes form one of the most important classes of synthetic polymers. Urethane

foams occupy only a small percentage of the plastics industry at present, but in light of the

newness of urethanes and the rapid advancement in properties and property improvement the

end-use possibilities and growth for foams have exciting predictions.

One component foam is a semi rigid foam that is a self-expanding and self-adhesive

moisture curing gap filler with the main advantage that it is dispensed from a simple pressurized

container or aerosol-type and requires no mechanical or power source.

There are several methods to evaluate foams. In previous stages only the quick test sheet

that allows comparisons between the foam properties was used. In advanced phases of the

work tests like physical, AltaFoam Monitor, Dimstab and the door test were performed.

With the growing environmental concerns, the need to use environmentally friendly

compounds is increasing and polyurethanes foam industry does not escape from that.

The main conclusion of this work is that there are several reagents and additives that are

used in PU chemistry and that when a change is performed in one reagent it will have an impact

on the other ones, since the equilibrium between reagents and properties is broken. In other

words, the foam properties are not independent of each other and the same is true for the

reagents.

An easier way to make changes and try to analyse the real influence of each reagent on

each property when there are just a few properties to improve, is to modify one reagent in one

round of formulations and verify the differences that occur between formulations.

64

9. References

1. Phillips, L.N., Parker, D.B.V., Polyurethanes, Ed. of The Plastic Institute, 1st Edition,

1964, p1-5

2. Szycher, M., Szycher’s Handbook of Polyurethanes, 1st Edition, CRC Press, 1999

3. Woods, G., The ICI Polyurethanes Book, Ed. John Wiley& Sons, 1987

4. Lee, S.T., Armes, N.S., Polymeric Foams – Mechanisms and Materials, 1st Edition,

CRC Press, 2004, p1

5. Billmeyer Jr., F.W., Textbook of Polymer Science, 3rd

Edition, John Wiley& Sons, 1984

6. Pigott, K.A., Polyurethanes, John Wiley& Sons, 1969

7. Solomons, G., Fryhle, C., Organic Chemistry, 7th Edition, John Wiley& Sons, 2000

8. Bruins, P.F., Polyurethane technology, John Wiley & Sons, 1969, p3-4

9. Salamone, J.C., Polymeric Materials Encyclopedia – Volume 9, CRC Press, 1996

10. Schrijver, A., Cuvelier, D., 1K PU Foam is not equal to 1KPU Foam, Utech

Presentation, March 2003

11. Doyle, E.N., The Development and Use of Polyurethane Products, McGraw-Hill, 1971

12. Vilar, W., Química e Tecnologia dos Poliuretanos, www.poliuretanos.com.br, p11-15,

accessed in August 2008

13. Schrijver, A., Development guidelines on speciality PU foams in aerosol cans, Internal

Report, 15/09/2001

14. Claro, J.C., Poliuretanos, UTAD, 2001, p30, 68

15. Clara, M.N., Santos, C., Bordado, J.C., Rev. Sociedade Portuguesa de Química, 1986,

p24, 60

16. Elvers, B., Hawkins, S., Schulz, G., Ullmann’s Encyclopedia of Industrial Chemistry –

Volume A21, 5th Edition, VCH, 1992

17. www.multisimplex.com, accessed in September 2008

18. Schrijver, A., OCF Benchmarking Test, Altachem, Internal Report, 11/03/2004

19. User’s guide to AltaFoam Monitor, Altachem, Internal Report

20. Practical Manual DIMSTAB, Altachem, Internal Report

21. Brilhante, M., Maertelaere, C., OCF Doorstand Report, Altachem, 06/2008

22. Information gently provided by Cathy De Maertelaere

23. Schrijver, A., One Component Foams, a European technology, proven true worldwide,

Altachem, Internal Report, p4

24. http://goliath.ecnext.com/, accessed in September 2008

25. http://www.honeywell.com, accessed in September 2008

65

10. Appendix

10.1. Appendix 1 – Quick Test of HBA1 and F134a formulations

F134 Samples

66

HBA1 Samples

67

10.2. Appendix 2 – Quick Test of SoudaFoam Report

5527 5528 Paper Short

Threshold 23/23

Threshold 5/5

Rating 23/23 5/5 23/23 5/5

Foam On Paper AC/NAC NAC NAC NAC NAC

Shaking Rate SR 3 3 [-5 ; +5] 4 3,75 3,5 2,75

Froth Shrinkage Shrink 3 3 [-5 ; +5] 5 5 5 5

Froth Outflow Flow 2,5 2,5 [-5 ; +5] 5 5 5 5

Surface structure SS SM/FR FR FR FR SM

Crumbling > 24h 5 3,5 [-5 ; +5] 5 5 5 5

Glass Bubbles GB 3 2,5 [-5 ; +5] 4,5 4 4 3

Cell Structure Rating CS 3 2,5 [-5 ; +5] 3,75 3 3 3

Voids & Pin Holes Rating

V&PH 2,5 2,5 [-5 ; +5] 3,5 3 3 3

Baseholes Rating BH 2,5 2,5 [-5 ; +5] 2 0 2,25 1

Cell Collapse Rating CC 4 3 [-5 ; +5] 4 1,5 4,25 4

Curing Streaks Rating Cstreaks 2,5 2,5 [-5 ; +5] 5 5 5 5

5527 5528 Mould Short

Threshold 23/23

Threshold 5/5

Rating 23/23 5/5 23/23 5/5

Foam In Mould FIM AC/NAC NAC NAC NAC NAC

Mould release MR L/NL L L NL NL

Surface structure SS SM/FR SM SM FR FR

Curing Shrinkage Curing 3,5 3,5 [-5 ; +5] 5 4 5 5

Glass Bubbles GB 3 2,5 [-5 ; +5] 4,25 3,75 3,75 3,5

Side Base Holes SBH 3,5 3,5 [-5 ; +5] 3,25 2,5 2,25 2,5

Cell Structure Rating CS 3 2,5 [-5 ; +5] 3 2,75 3 3

Voids & Pin Holes Rating

V&PH 2,5 2,5 [-5 ; +5] 3 3 3 3

Baseholes Rating BH 2,5 2,5 [-5 ; +5] 2 1 3,25 2

Cell Collapse Rating CC 4 3 [-5 ; +5] 1 3 4,25 4,25

Curing Streaks Rating Cstreaks 2,5 2,5 [-5 ; +5] 5 5 5 5

5527 5528 Density Mould Rating

23/23 5/5 23/23 5/5

Overall Density Mould ODm [g/L] 19,07 - 14,28 -

5527 5528 Output Rating

23/23 5/5 23/23 5/5

Output Liquid liquid [g/s] - 19,6 - 11,4

Output Foam Foam [g/s] - 17,6 - 10,6

Gas Loss at dispensing

[%] - 10,2 - 7,3

GENERAL INFO 5527 5528

Can Pressure [bar] 4,00 bar 4,00 bar

Can Weight [g] 886,0 g 703,8 g

68

10.3. Appendix 3 - AFM of SoudaFoam Report

5527, Soudafoam

69

70

5528, Soudafoam Alternative

71

72

73

10.4. Appendix 4 – Physical tests of SoudaFoam Report

5527, Soudafoam

74

5528, Soudafoam Alternative

75

76

10.5. Appendix 5 – Quick Test of AEB3 Project

3864 AEB3 Paper

Threshold 23/23

Threshold 5/5

Rating 23/23 5/5

Foam On Paper AC/NAC AC NAC

Shaking Rate 3 3 [-5 ; +5] 4 3

Froth Shrinkage 3 3 [-5 ; +5] 5 4,75

Froth Outflow 2,5 2,5 [-5 ; +5] 5 4,5

Surface structure SM/FR SM SM

Crumbling 5 3,5 [-5 ; +5] 5 5

Glass Bubbles 3 2,5 [-5 ; +5] 5 4

Cell Structure Rating 3 2,5 [-5 ; +5] 4 3,25

Voids & Pin Holes Rating

2,5 2,5 [-5 ; +5] 4 4

Baseholes Rating 2,5 2,5 [-5 ; +5] 4,25 0,75

Cell Collapse Rating 4 3 [-5 ; +5] 4 -1,75

Curing Streaks Rating 2,5 2,5 [-5 ; +5] 4 4,75

3864 AEB3 Mould

Threshold 23/23

Threshold 5/5

Rating 23/23 5/5

Foam In Mould AC/NAC AC AC

Mould release L/NL NL NL

Surface structure SM/FR SM SM

Curing Shrinkage 3,5 3,5 [-5 ; +5] 5 5

Glass Bubbles 3 2,5 [-5 ; +5] 5 4,25

Side Base Holes 3,5 3,5 [-5 ; +5] 5 4

Cell Structure Rating 3 2,5 [-5 ; +5] 4 3,75

Voids & Pin Holes Rating

2,5 2,5 [-5 ; +5] 4 4,25

Baseholes Rating 2,5 2,5 [-5 ; +5] 5 4,5

Cell Collapse Rating 4 3 [-5 ; +5] 4,25 4,25

Curing Streaks Rating 2,5 2,5 [-5 ; +5] 4 5

3864 AEB3 Density Mould Rating

23/23 5/5

Overall Density Mould [g/L] 30,01 -

3864 AEB3 Output Rating

23/23 5/5

Output Liquid [g/s] - 15,5

Output Foam [g/s] - 14,2

Gas Loss [%] - 8,4

GENERAL INFO 3864 AEB3

Can Pressure [bar]

Can Weight [g] 887,0 g

77

3883 3884 3885 3886 3887 3888 PAPER

23/23 5/5 23/23 5/5 23/23 5/5 23/23 5/5 23/23 5/5 23/23 5/5

NAC NAC NAC NAC NAC NAC NAC NAC NAC AC NAC NAC

SR 4 2,75 3,75 2,75 4 2,75 4,25 2,75 3,75 3 3,75 2,75

Shrink 5 5 5 5 5 5 5 5 5 5 5 5

Flow 4,5 4 4,5 4 4 4 4 4 4,25 4 4,25 4

SS SM SM SM SM SM SM SM SM SM SM SM SM

CR > 24h 5 5 5 5 5 5 5 5 5 5 5 5

GB 4,75 4 4,75 4 4,75 4 4,75 4 4,75 4 4,75 4

CS 2,75 2,75 2,75 2,75 2,75 2,75 2,75 2,75 2,75 2,75 2,75 2,75

V&PH 3 4 2,5 4 2 2,5 2,5 2 3 3 3 2

BH 4 3,5 4,25 3,5 4 3,5 4 3,5 4,5 3,5 4,5 3

CC 2,5 0 2,5 3 3 2,5 3,5 2,5 3 3 3,5 0

Cstreaks 5 5 5 5 4,75 5 4,75 5 4,75 5 4,75 5

3883 3884 3885 3886 3887 3888 MOULD

23/23 5/5 23/23 5/5 23/23 5/5 23/23 5/5 23/23 5/5 23/23 5/5

FIM AC AC AC AC AC AC NAC AC AC AC NAC AC

MR NL NL NL NL NL NL NL NL NL NL NL NL

SS SM SM SM SM SM SM SM SM SM SM SM SM

Curing 5 5 5 5 5 5 5 5 5 5 5 5

GB 4 3,75 4 3,75 4 3,75 4 3,75 4 3,5 4 3,5

SBH 5 4 4,5 4,5 4,75 4 5 4 4,5 4,5 5 3,75

CS 3 3 3 3 3 2,75 2,75 2,75 3,25 3 3 3

V&PH 3 3 3 4 4 3 3 3 3,75 4 2,75 3

BH 4 3,25 4,5 3,25 4,25 3,25 4,25 3 5 2,75 4,25 2,75

CC 4,25 3 4 4 4,25 2,5 4,25 4 4,5 3 3,25 4

Cstreaks 5 5 5 5 4,75 4,5 4,5 4,75 4,75 5 5 4,5

3883 3884 3885 3886 3887 3888 Density

23/23 5/5 23/23 5/5 23/23 5/5 23/23 5/5 23/23 5/5 23/23 5/5

ODm 24,86 - 25,08 - 25,86 - 25,51 - 24,83 - 24,71 -

3883 3884 3885 3886 3887 3888 Output

23/23 5/5 23/23 5/5 23/23 5/5 23/23 5/5 23/23 5/5 23/23 5/5

liquid - 22,4 - 21,1 - 24,7 - 23,2 - 24,3 - 24,3

Foam - 20,4 - 19,3 - 22,6 - 21,2 - 22,1 - 22,0 at

dispensing - 9,0 - 8,5 - 8,5 - 8,5 - 9,0 - 9,4

INFO 3883 3884 3885 3886 3887 3888

Can P

Can W 885,2 g 881,6 g 880,5 g 882,4 g 879,7 g 881,0 g

78

3908 3910 3960 3961 6003 6020 PAPER

23/23 5/5 23/23 5/5 23/23 5/5 23/23 5/5 23/23 5/5 23/23 5/5

NAC AC AC NAC NAC NAC NAC NAC NAC AC NAC NAC

SR 4 3,5 4 3,25 4,25 3 4,5 3 4,5 3 4,5 3

Shrink 5 5 5 5 5 5 5 5 5 5 5 5

Flow 4,5 4 4,5 4 4,75 4,5 5 4 4,5 4,5 4 4

SS SM SM FR FR FR SM FR FR SM SM SM SM

CR > 24h 5 5 5 5 5 5 5 5 5 5 5 5

GB 4,75 4,5 5 4,75 5 4,25 5 4,25 4,75 4,5 4,75 4,5

CS 2,5 2,75 3 3 3 2,75 2,75 3 3 3 3 2,75

V&PH 4 3 3 2 3 3 3 2 4 4 2,5 4

BH 4 3,25 4 3,5 4 2,5 4,75 3 4,5 3 4,25 3,75

CC 3 3 4 -1 3 -1 2,75 -3 1,5 3 3 -5

Cstreaks 5 4,75 4 4 4,75 4,75 4,5 4,75 5 5 4,75 5

3908 3910 3960 3961 6003 6020 MOULD

23/23 5/5 23/23 5/5 23/23 5/5 23/23 5/5 23/23 5/5 23/23 5/5

FIM NAC NAC NAC NAC NAC NAC NAC NAC NAC AC AC NAC

MR NL NL NL NL NL NL NL NL NL NL NL NL

SS SM SM SM SM SM SM SM SM SM SM SM SM

Curing 5 5 5 5 5 5 5 5 5 5 5 5

GB 4,5 4 4,75 4 4 4 4 4 4 4 4 3,75

SBH 5 4 4,5 3,5 4,25 3 4,5 4 4,5 5 5 4,75

CS 2,75 3,25 3,25 3 2,75 4 2,75 3,5 3 3 3 2,5

V&PH 4 4 2 2 3,5 0 4 1 4 4,25 3,5 3

BH 4,5 2 4,5 3,75 4 0 4,75 3 4,5 3 4,5 2

CC 4,5 4,5 2 -4 4 0 4,5 1 1 4,5 4 3

Cstreaks 4,75 5 0 4,5 5 4,5 5 5 4,75 5 4,5 4,75

3908 3910 3960 3961 6003 6020 Density

23/23 5/5 23/23 5/5 23/23 5/5 23/23 5/5 23/23 5/5 23/23 5/5

ODm 22,19 - 41,71 - 25,02 - 22,51 - 22,72 - 19,83 -

3908 3910 3960 3961 6003 6020 Output

23/23 5/5 23/23 5/5 23/23 5/5 23/23 5/5 23/23 5/5 23/23 5/5

liquid - 22,9 - 21,7 - 13,2 - 26,7 - 17,0 - 19,8

Foam - 20,9 - 19,7 - 11,8 - 23,7 - 15,7 - 18,1 at

dispensing - 8,7 - 9,3 - 10,7 - 11,1 - 7,4 - 8,7

INFO 3908 3910 3960 3961 6003 6020

Can P 4,50 bar 4,50 bar 5,10 bar 5,50 bar 4,50 bar 3,90 bar

Can W 884,7 g 880,7 g 881,1 g 888,0 g 876,9 g 879,8 g

79

6021 6022 6043 6044 6064 6065 PAPER

23/23 5/5 23/23 5/5 23/23 5/5 23/23 5/5 23/23 5/5 23/23 5/5

NAC NAC NAC NAC AC NAC NAC NAC NAC NAC NAC NAC

SR 4,5 3,25 4,25 3,5 4,75 4 4,75 4,25 4,5 3,75 4 3,75

Shrink 5 5 5 5 5 4,5 5 4,5 5 5 5 5

Flow 4 4 4 4 4,25 4 4,25 4 4 3,5 4 3,5

SS SM SM SM FR SM SM SM SM FR FR FR FR

CR > 24h 5 5 5 5 5 5 5 5 5 5 5 5

GB 4,75 4,5 4,75 4,5 5 4,75 5 4,75 4,75 4,25 4,75 4,25

CS 3 3 3,25 3 4,25 3,75 4,25 3,25 3,25 3,25 4 3

V&PH 3,5 4 3 4 3,5 0,75 2,75 1 4 3 3 4

BH 4 3,75 3,5 3,5 4 2,75 3,5 2,5 4 3,5 4,5 3,75

CC 0,5 -3 2 1 4,25 2,75 3,75 3,25 1 1 3 -2

Cstreaks 4,25 4,75 4,75 5 5 5 5 5 4,5 4,75 4,25 5

6021 6022 6043 6044 6064 6065 MOULD

23/23 5/5 23/23 5/5 23/23 5/5 23/23 5/5 23/23 5/5 23/23 5/5

FIM AC NAC NAC AC AC NAC NAC NAC AC NAC NAC NAC

MR NL NL NL NL NL L NL NL NL NL NL NL

SS SM SM SM FR SM SM SM SM SM SM SM SM

Curing 5 5 5 5 5 5 5 5 5 5 5 5

GB 4 3,75 4 4 5 4,5 5 4,5 4 4 4 4

SBH 4,5 5 4,25 4,75 4,75 3 4,25 3,75 4,25 3,25 4,25 3

CS 3 3 2,75 2,75 4 4 4 3,25 3,25 3 3,25 3

V&PH 3,5 4 3 4 3,75 0 2,5 3 3,5 4 3,5 3

BH 4,25 2,25 4,25 3 4,25 2,75 4,25 0,5 4,75 3 4,5 3,5

CC 4,25 4 3,75 4 4 0 3,75 3,5 4 4 3,25 4,25

Cstreaks 4,25 5 4,5 5 4,75 4,75 4,75 5 4,5 5 4,25 5

6021 6022 6043 6044 6064 6065 Density

23/23 5/5 23/23 5/5 23/23 5/5 23/23 5/5 23/23 5/5 23/23 5/5

ODm 23,25 - 26,11 - 33,05 - 31,52 - 28,18 - 29,17 -

6021 6022 6043 6044 6064 6065 Output

23/23 5/5 23/23 5/5 23/23 5/5 23/23 5/5 23/23 5/5 23/23 5/5

liquid - 19,5 - 18,2 - 27,1 - 35,6 - 23,6 - 23,4

Foam - 17,7 - 16,5 - 24,3 - 31,6 - 21,6 - 21,3 at

dispensing - 9,4 - 9,2 - 10,4 - 11,2 - 8,4 - 9,1

INFO 6021 6022 6043 6044 6064 6065

Can P 4,00 bar 4,10 bar 5,10 bar 5,10 bar 4,90 bar 4,80 bar

Can W 874,4 g 874,6 g 879,0 g 882,9 g 874,3 g 875,7 g

80

6066 6082 6083 6096 6097 6098 6099 PAPER

23/23 5/5 23/23 5/5 23/23 5/5 23/23 5/5 23/23 5/5 23/23 5/5 23/23 5/5

NAC NAC NAC NAC AC NAC AC NAC NAC NAC NAC NAC NAC NAC

SR 4,5 3 4 3 3,75 2,75 4,25 3,25 3,75 3 4,5 3,25 4,5 3

Shrink 5 5 5 5 5 5 5 5 5 5 5 5 5 5

Flow 4 3,5 4 4 4 4 4,5 4,5 4,5 4,5 4,5 3,75 4,5 3,75

SS FR FR FR FR FR SM FR SM FR SM FR FR FR SM

CR > 24h 5 5 5 5 5 5 5 5 5 5 5 5 5 5

GB 4,75 4,25 4,75 3,75 4,75 3,75 4,75 4 4,75 4 4,75 4 4,75 3,75

CS 3,5 3,25 4 3,75 4 3,75 4,5 3,25 4,5 3,25 4 3,75 4 3,5

V&PH 3,5 3 3 4 4 4 3 4,5 4 4,5 4 4,5 4 4

BH 4,25 3,75 4,5 3,5 4,5 3,5 4 3,5 4 4 4 3 4 3

CC 1 -1 3 0 4,25 -3 4 -1 3,5 -2 3,25 -1 3 -2

Cstreaks 4,25 4,75 4,75 5 5 4,5 5 4,75 4,75 4,75 4,5 4,75 4,75 4,75

6066 6082 6083 6096 6097 6098 6099 MOULD

23/23 5/5 23/23 5/5 23/23 5/5 23/23 5/5 23/23 5/5 23/23 5/5 23/23 5/5

FIM AC AC AC AC AC NAC AC AC NAC NAC AC AC AC NAC

MR NL NL NL NL NL NL NL NL NL NL NL NL NL NL

SS SM SM SM SM SM SM SM SM SM SM SM SM SM SM

Curing 5 5 5 5 5 5 5 5 5 5 5 5 5 5

GB 4 4 4 4 4 4 4 3,75 4 3,75 4 4 4 4

SBH 4,5 3,5 4,25 4,25 3,75 3,25 4,5 3,75 3,75 3,5 4,25 4,5 4 3

CS 3,25 3 4,25 3,5 3,75 3 3,5 3 3,5 3 3,5 3 3,5 3

V&PH 4 4,25 4 4 3,5 4 4 4,5 4 4,25 4 4 4 4

BH 4 3,5 4 3 4,25 3 4 2,75 4,25 2 4,25 2,75 4 3,5

CC 4,25 4 4 3,5 4,25 2,5 4 4 3,75 4 4,25 3,5 4,25 4,25

Cstreaks 4,5 5 4,75 5 5 5 5 5 4 5 4,5 5 4,5 5

6066 6082 6083 6096 6097 6098 6099 Density

23/23 5/5 23/23 5/5 23/23 5/5 23/23 5/5 23/23 5/5 23/23 5/5 23/23 5/5

ODm 26,24 - 24,90 - 25,46 - 24,56 - 28,45 - 25,13 - 23,45 -

6066 6082 6083 6096 6097 6098 6099 Output

23/23 5/5 23/23 5/5 23/23 5/5 23/23 5/5 23/23 5/5 23/23 5/5 23/23 5/5

liquid - 24,7 - 16,3 - 11,4 - 10,6 - 9,6 - 15,5 - 12,2

Foam - 22,3 - 14,5 - 10,2 - 9,5 - 8,8 - 14,1 - 10,9 at

dispensing - 9,9 - 11,2 - 10,8 - 10,0 - 7,9 - 9,0 - 10,4

INFO 6066 6082 6083 6096 6097 6098 6099

Can P 4,70 bar 4,90 bar 4,80 bar 4,50 bar 4,40 bar 4,40 bar 4,50 bar

Can W 878,2 g 877,8 g 876,0 g 879,8 g 877,6 g 873,3 g 883,3 g

81

10.6. Appendix 6 – Physical Tests of 6096 AEB3

Adhesion F6096 23°C/23°C

0

10

20

30

40

50

60

70

0 2 4 6 8 10 12 14

Strain (%)

Str

ess (kPa)

SHEAR STRENGTH F6096 23°C/23°C

0

10

20

30

40

50

60

70

80

0 5 10 15 20 25

Strain (%)

Str

ess (kPa)

82

COMPRESSION F6096 23°C/23°C

0

5

10

15

20

25

30

35

40

45

50

0 1 2 3 4 5 6 7

Compression (mm)

Str

ess (kPa)

83

10.7. Appendix 7 – AFM of 6096 AEB3

84

85