CARL HANSER VERLAG

Alphonsus V. Pocius

Adhesion and Adhesives Technology An Introduction

3-446-21731-2

www.hanser.de

1 Introduction

1.1 Introduction and Chapter Objectives

Adhesive bonding is a method by which materials can be joined to generate assemblies.

Adhesive bonding is an alternative to more traditional mechanical methods of joining

materials, such as nails, rivets, screws, etc. Adhesive bonding is not a new joining method.

Use of adhesives is described in ancient Egypt [1] and in the Bible [2]. Bommarito [3]

describes recipes for adhesives that were formulated during the Middles Ages. One such

recipe shows that people in the middle ages had an appreciation for the generation of

composite materials as well as the use of drying oils:

‘‘Very Strong, Very Good Glue’’

‘‘Take clay roof tiles and grind them to a fine powder using a flour grinder. Add a similar amount of iron

rust, also ground to a fine powder. Add live lime in an amount equivalent to the clay and iron rust and

incorporate the mixture with linseed oil. Use immediately to glue what you want as this glue is better when

used fresh than otherwise.’’

A major step in adhesive technology took place in the early 1900s with the advent of

synthetically prepared adhesives. Thus, widespread use of adhesives as a joining medium is

a relatively recent phenomenon.

All joining methods have their advantages and disadvantages and adhesive bonding is not

an exception. This introductory chapter explores some of the positive and negative features

of adhesive bonding as a joining method. Exploring these features sets the stage for many of

the chapters to follow. The objectives of this chapter are

� to acquaint the reader with the basic definitions used in adhesion science

� to provide the reader with a basis for understanding the advantages and

disadvantages of using adhesive bonding

� to discuss the place of adhesive technology in our economy and to provide

examples of where adhesives are utilized

� to describe sources of information about adhesion and adhesives for those

who are becoming practitioners of the art and science of adhesive bonding.

1.2 Basic Definitions

An assembly made by the use of an adhesive is called an adhesive joint or an adhesive

bond. Solid materials in the adhesive joint, other than the adhesive, are known as the

adherends. The phenomenon, which allows the adhesive to transfer a load from the

adherend to the adhesive joint, is called adhesion. There is also the phenomenon of

abhesion, which is the condition of having minimal adhesion. This property is important

when an assembly is needed from which the adhesive can be removed on demand. Materials

that exhibit abhesion are also known as release materials and they are used to make certain

pressure-sensitive adhesive constructions. Pressure-sensitive adhesives are described in

Chapter 9.

The actual strength of an adhesive joint is primarily determined by the mechanical

properties of the adherends and the adhesive. The term we apply to the measured physical

strength of an adhesive bond is practical adhesion. The primary purposes of this book are

to describe the phenomenon of adhesion, to describe the chemistry and properties of

adhesives, and to discuss the current understanding of the relationship between practical

adhesion, adhesion, and the mechanisms of energy dissipation in the adhesive joint.

1.3 Advantages and Disadvantages of AdhesiveBonding

One major differentiation between an adhesive joint and a mechanically fastened joint is

that in the second, a mechanical fastener must pierce the adherend in order to execute an

assembly. When a mechanical fastener pierces an adherend, or if the adherend is pierced

before the installation of a mechanical fastener, a hole is created in the adherend.

In Fig. 1.1 we see two examples of an adherend. In Fig. 1.1(a), the adherend is intact. If a

load was applied to the adherend, the lines of force propagating through the adherend would

be continuous. If instead, the adherend had a hole in it (such as depicted in Fig. 1.1(b)), the

lines of force could not be continuous through the adherend and would have to go around

the hole. Thus, at the edges of the hole, the force experienced by the material is much larger

than the force experienced by the material remote from the hole. The edges of the hole not

only have to support the force that is applied to those edges, but also must support the force

that should have been supported by the material that would have been in the hole. As we

will find in Sections 2.4 and 3.5.1 on fracture mechanics, this situation is known as a stress

concentration. A stress concentration can cause a decrease in many physical properties of

the adherend as well as those of the mechanical joint. In contrast, if an adhesive is used to

generate an assembly, no hole is generated in the adherend. Therefore, the physical

properties of the adherend are maintained after the assembly has been created.

The use of mechanical fasteners in a joint can lead to several problems that are not present

when adhesives are used. First, the overall strength of the joint can be reduced. Second, the

joint can experience early fatigue failure. Third, if either of the adherends is sensitive to

shock, the act of applying the mechanical fastener could cause the assembly to fail.

Adhesive bonds, when executed in a properly designed adhesive joint, do not exhibit high

stress concentrations, so the properties of the adherends can be fully utilized. However,

adhesive joints do require a much larger area of contact between the adherends and the

2 Introduction

adhesive in order to carry the same load as a mechanical fastener. Some of the criteria for

the proper design of an adhesive joint are described in Chapters 3 and 11.

For the most part, adhesives are polymeric materials that exhibit viscoelastic properties.

Materials that display viscoelasticity have both a viscous character as well as an elastic

character. These terms are described in more detail in Chapters 2 and 5. Polymer-based

adhesives absorb mechanical energy applied to the joint and dissipate that energy as heat.

Hence, fatigue failures are delayed in comparison to mechanical fastening. For example,

Schliekelmann [4] describes the increase of fatigue life for joints made by a combination of

mechanical fastening and adhesive bonding. Table 1.1 shows this data. The increase in

fatigue life of the combination joint is obvious. The viscoelastic properties of adhesives and

the role they play in the adhesive bonding and debonding process are discussed in Chapters

2, 5, 6 and 9.

Finally, many adhesives do not require input of mechanical energy to effect an assembly.

Hence, shock-sensitive materials can be easily made into an assembly. For example, one

would not consider joining of dynamite sticks with nails. However, dynamite sticks can be

easily joined by pressure-sensitive adhesive-backed tape.

Figure 1.1 Diagram showing lines of force through a monolithic body (a) and a body containing an

elliptical hole (b). The lines of force pass continuously through (a) but are unable to do so in (b). This

results in a stress concentration at the edges of the elliptical hole.

1.3 Advantages and Disadvantages of Adhesive Bonding 3

The primary disadvantage of adhesive bonding is that it relies on adhesion for the transfer

of load through the assembly. Adhesion is a surface physico-chemical phenomenon that is

discussed in Chapters 4 and 6. Since adhesion is a surface phenomenon, it follows that the

physical properties of the adhesive joint depend strongly on the character of the surface of

the adherend and how the adhesive interacts with that surface. Thus, an adherend with an

improper surface could lead to lower joint strengths than might be predicted from the

mechanical properties of the adhesive and the adherend. Surface problems are even more

important when one tries to generate adhesive bonds that are durable in adverse environ-

ments. The need for a proper surface, and the fact that it is not always available, are

disadvantages of adhesive bonding in comparison to mechanical fasteners, which are

not affected by the state of the surface of the members of a joint. Practical methods by

which one can generate surfaces that are amenable to adhesive bonding are discussed in

Chapter 7.

Adhesives display several other advantages over mechanical fastening. One of these

advantages is the reason for the widespread use of adhesives in the aerospace industry,

specifically the ability of adhesives to not only form a joint, but also to seal the assembly in

one step. Mechanical fastening often requires separate sealing steps to create a pressurizable

assembly. Adhesives also allow galvanically dissimilar materials to adhere to one another

without accelerating corrosion. For example, the mechanical joining of steel and aluminum

would be a disaster in the making. Aluminum would act as an anode to steel and corrode

rapidly in corrosive environments. Since most polymeric adhesives are non-ionic and

electrical insulators, a properly effected adhesive bond would electrically separate the

members of the galvanic couple while still joining them structurally.

However, mechanical fastening does have a number of advantages over adhesive bonding.

Once a mechanical fastener is applied, one certainly knows that it is there. Adhesives, by

their nature, are internal to the joint. In most cases, it is not easy to determine (without

destructive testing) whether the adhesive was properly applied. This lack of non-destructive

quality control has led to entire studies on methods by which adhesive bonds can be

inspected in a non-destructive fashion. One other advantage of mechanical fasteners over

adhesive bonding is that the engineering of mechanically fastened assemblies is part of

many schools’ curricula. However, there is a paucity of courses on the engineering of

adhesively bonded structures. Thus, there may be a certain lack of confidence in the use of

adhesives among engineers and designers. It is hoped that this book will increase

Table 1.1 Comparison of Fatigue Life of Joints (Aluminum Adherends,

4 cm lap and 1mm Adherend Thickness)

Sample Fatigue life (cycles)

Riveted 211,000

Riveted and sealed (using an elastomeric sealant) 42,000

Riveted and adhesively bonded using a 2-part epoxy >1,500,000

4 Introduction

confidence in the use of adhesives and potentially lay the groundwork for an engineering

curriculum in this area.

Tables 1.2 and 1.3 show a compilation of comparisons of a well-known joining method,

welding, to adhesive bonding as compiled by Lees [5]. The features of adhesive bonding

versus welding further highlight the advantages and disadvantages of the former versus the

latter.

1.4 Uses of Adhesive Bonding in Modern Industry

For thousands of years, adhesive bonding has been used in the production of veneered

furniture. Many examples of veneered furniture from Egyptian and Roman times are found

Table 1.2 Comparison of Welding versus Adhesive Bonding in Terms of Their Production

Characteristics

Welding Adhesive bonding

Little or no substrate preparation is

necessary

Adherend surface preparation is often

necessary

Post-heat treatment is sometimes necessary Post-cure is often advantageous

Welding equipment is expensive, heavy and

power intensive

Equipment is only sometimes necessary

and may be as simple as an oven

Wires, rods and welding tips are inexpensive

(except for aluminum)

Adhesives are moderately expensive,

depending upon type

Production rate can be rapid Production rate can be rapid but is heavily

dependent upon the adhesive

Non-destructive tests are applicable but are

expensive

Non-destructive tests are available but are

not predictive of bond strength

Welder must remove heat sensitive and/or

flammable materials away from the

welding operation

No need to remove heat sensitive materials

from the bonding area, dependent upon

cure conditions

Table 1.3 Comparison of Welded Joints versus Adhesive Bonds

Welded joint Adhesive bond

Permanent Permanent (with proper surface preparation)

Local stress points Predominantly uniform stress distribution

Joints often have to be ‘‘dressed’’ for aesthetics No surface markings

Useful only for identical materials Dissimilar materials are easily joined

High temperature resistance Low to moderate temperature resistance

Poor fatigue resistance Excellent fatigue resistance

1.4 Uses of Adhesive Bonding in Modern Industry 5

in museums. Adhesives were also used for the generation of wooden musical instruments.

In more recent times, adhesives are still used in the generation of veneered wood. In

addition, adhesives are used in a far wider array of applications than could have been

imagined by our ancestors. The primary boost in the use of adhesives came with the advent

of synthetic polymeric materials with improved mechanical properties.

There are many types of adhesives, both organic and inorganic. The inorganic adhesives are

familiar to most people and include materials such as Portland cement and solder. The

chemistry and physical properties of these adhesives are not discussed in this book although

the sections on mechanical properties and surfaces for organic materials apply just as well

to these adhesives. Rather, the adhesives discussed in this book are those that are based

entirely or primarily on organic materials. The chemistry and physical properties of these

polymer-based adhesives are discussed in Chapters 8–11.

Since these adhesives are organic in nature, they normally have a lower specific gravity than

either the inorganic adhesives mentioned above or most adherends. Thus, assemblies

produced with polymer-based adhesives weigh less than those produced with inorganic

adhesives or with metallic fasteners, a major advantage in the aerospace industry where

lightweight structures are of paramount importance.

Despite the fact that the use of adhesives is not part of many engineering curricula, there are

many examples of the use of adhesive bonding in industry. The aerospace industry uses

adhesive bonding to great advantage in the construction of many components. Figure 1.2 is

Figure 1.2 Diagram of a Fokker F-100 aircraft showing the sections of the aircraft that are adhesively

bonded. Note that a substantial amount of the fuselage is constructed using structural adhesives.

(Diagram courtesy of the Fokker Aircraft Company, The Netherlands, reprinted with permission.)

6 Introduction

a diagram of a Fokker F-100 passenger aircraft, indicating the areas that are adhesively

bonded. It is easy to see that much of the fuselage, the wing structure, and the engine

housing are at least partially adhesively bonded. What is not apparent from the figure is that

many of the internal components in the aircraft cabin are also adhesively bonded. For

example, floor panels are a special construction of a material known as Nomex1 honeycomb

core adhesively bonded to fiberglass panels. The overhead compartments are made in a

similar way. These constructions are not only lightweight but they are also stiff. Many of the

types of adhesives that are used in the aerospace industry are discussed in Chapter 8.

The automobile industry also uses adhesives extensively. Figure 1.3 shows locations of an

automobile where adhesives are used. For example, automobile hoods are typically

constructed of a top panel and a stiffener. The stiffener is joined to the top panel by

‘‘anti-flutter’’ adhesives that allow the hood to maintain its shape even under high stresses

and wind shear. In newer automobiles, the windshield is part of the overall structure of the

roof and is fastened by adhesives to the frame. Automobile doors are often adhesively

bonded in an assembly known as the ‘‘hem-flange’’ in which the outer door is bonded to an

inner shell. The outer door is crimped around the inner shell and the two pieces are joined

1 ‘‘Nomex’’ is a trademark of E.I. DuPont de Nemours Co.

Figure 1.3 Diagram of an automobile body showing at least 15 locations in which adhesives and

sealants could be used or are being used. Particular note should be made of the windshield (8), which

is considered a load bearing structure in modern automobiles and is adhesively bonded. Attention

should also be paid to hem-flange bonding (1) in which adhesives are used to bond and seal.

Adhesives are used to bond friction surfaces in brakes and clutches (10). Anti-flutter adhesive bonding

(2) helps control deformation of hood and trunk lids under wind shear. Thread-sealing adhesives are

used in engine applications (12).

1.4 Uses of Adhesive Bonding in Modern Industry 7

and sealed by adhesive bonding. Figure 1.4 shows the use of adhesives in the manufacture

of a frame for an autobus. The potential weight savings inherent in adhesive bonding are a

major reason for their increased use as automotive technology advances. In addition, using

a combination of adhesive bonding and spot-welding (sometimes known as ‘‘weld-

bonding’’), provides improvements in the noise and vibration characteristics of the

automobile chassis.

Great use of adhesives is found in the wood products industry. Plywood manufacturers use

tank car quantities of various types of adhesives, ranging from those made with natural

products to those made from synthetic materials, such as phenol-formaldehyde polymers.

Similar materials are used to make pressboard and chipboard, both of which are used

extensively in home construction. Figure 1.5 shows a construction worker applying

adhesives to joists in a home construction project. When floorboards are adhesively

bonded to joists, the floor tends to be stiffer but quieter than when nails are used exclusively

in a similar construction.

Adhesives are also used in the manufacture of furniture and cabinets. In particular,

adhesives are used to make laminates incorporating materials such as Formica1 bonded

to pressboard. Figure 1.6 shows how a rubber-based adhesive is spray-applied to a veneer

and a base wood. The two materials are later laminated to generate the furniture article.

Adhesives are widely used in other aspects of home construction as well. Floor and wall tile

Figure 1.4 A production worker applies a paste adhesive to struts, which form the frame for an

autobus.

1 ‘‘Formica’’ is a trademark of The Formica Corp.

8 Introduction

is applied with rubber-based mastic cements. These materials are discussed in Chapter 9.

Similar adhesives are used to apply paneling. Wall coverings are also attached by adhesive

bonding. The paper industry, which might be considered a subset of the wood products

industry, also uses large quantities of adhesives. Hot melt adhesives, which are discussed in

Chapter 10, are used to seal cartons as well to bind paperback books. Moisture-activatable

adhesives are applied to envelopes and postage stamps. A relatively new adhesive

application is the Post-It1 re-positionable note.

One industry that is not widely recognized as a user of adhesives is the electronics industry.

In particular, the microelectronics industry uses adhesives in the construction of integrated

circuits and the generation of electronic devices. Figure 1.7 shows a diagram of a simple

integrated circuit. The combination of materials used to generate this integrated circuit is

known as the packaging. This term should be kept distinct from the term ‘‘packaging’’ that

is used in the consumer marketplace. One of the materials used in the microelectronics

package is a die-attach adhesive. This adhesive may be conductive or insulative but it is

used to attach the silicon chip or die to the leadframe. The entire assembly is covered with

an encapsulant to protect the circuit from the environment. Another, thermally conductive,

adhesive is used to attach a heat spreader to the top of the encapsulant to help keep the

integrated circuit cool. This industry has very strict requirements for these adhesives in

terms of their ionic cleanliness and their resistance to processing steps and environmental

exposure.

Consumer usage of adhesives is a growing portion of the market for adhesive technology. In

fact, in some cases, the consumer-oriented adhesive tradename has become synonymous

with the adhesive technology. For example, cyanoacrylate adhesives (discussed in Chapter 8)

Figure 1.5 A construction worker applies a mastic adhesive to the joists in a home construction

project. The use of a mastic adhesive in such an application provides for a quieter floor.

1 ‘‘Post-It’’. is a trademark of the 3M Company

1.4 Uses of Adhesive Bonding in Modern Industry 9

are widely known as Super-Glue1. One type of pressure-sensitive adhesive-backed tape

(discussed in Chapter 9) is recognized as Scotch2 tape. Poly(vinyl acetate) emulsions that

are used as wood bonding and paper adhesives are often called Elmer’s Glue3. Other

adhesive products are also well accepted in the consumer marketplace. Vinyl adhesives used

1 ‘‘Super-Glue’’ is a trademark of Chemence, Ltd2 ‘‘Scotch’’ is a trademark of the 3M Company3 ‘‘Elmer’s Glue’’ is a trademark of T. M. I. Assoc.

Figure 1.6 Photographs of a spray adhesive used in a lamination line. The top photograph shows a

spray head applying rubber-based adhesive to an adherend. The lower photograph shows a factory

worker placing adherends to be sprayed onto a conveyor belt for passage under the spray head.

10 Introduction

to repair such items as vinyl inflatables are not only widely sold to consumers but are also a

very good example of one of the primary theories of adhesion, the diffusion theory, which is

discussed in Chapter 6. Epoxy adhesives, which are widely used in the aerospace industry,

also are found in the consumer marketplace as two-part adhesives that come in tubes or

applicator packages. We see adhesives used in the packaging of consumer goods from the

sealing of blister packs to the closure of cereal boxes.

1.5 Economics of Adhesive Technology

A measurable percentage of chemical production is associated with the generation of

adhesives and related products. In the year 2000, the worldwide adhesive and sealant

industry is expected to reach a market total of $24 billion [6]. This number does not include

the rather significant amounts of adhesives used in plywood and chipboard manufacture.

The bulk of this production will be in North America, Europe, and the Far East. In 1998, the

U.S. adhesives market reached $14 billion, which is approximately the same amount as the

1992 worldwide market. This dollar value was obtained by the sale of 5.7 billion dry

pounds of adhesive. The global growth rate for adhesives is expected to be 3 to 4%.

Figure 1.7 A cross section of an integrated circuit ‘‘package.’’ Attention should be paid to the use of

adhesives in the ‘‘die-attach’’ application as well as the thermally conductive adhesive for attachment

of the heat spreader. Adhesion plays a large role in the reliability of this package in terms of the

retention of adhesion of the encapsulant to all of the components.

1.5 Economics of Adhesive Technology 11

The first major use of adhesives comes under the heading of ‘‘converting’’, which includes

the generation of various types of packaging and labeling. The second major use of

adhesives is in the construction industry and includes many of the applications discussed

earlier. The adhesive industry is considered a ‘‘fragmented’’ industry. There are a large

number of adhesive companies with fewer than 50 employees. Only a few adhesive

companies have more than 1000 employees. However, the industry saw a substantial

consolidation through the 1980’s and the 1990’s with the emergence of several large

companies that grew through the acquisition of smaller ones.

1.6 Literature and Other Sources of Information

Literature regarding adhesives and adhesion technology can be found primarily in patents,

which can be difficult to read. However, review of the patent literature is indispensable for

anyone wishing to produce innovative adhesive products.

There are many journals devoted to polymeric materials that are the essential ingredients

used in the adhesives discussed in this book. Journals such as Macromolecules, Journal of

Applied Polymer Science, and Polymer Science and Engineering, etc., are indispensable for

keeping up with progress in this field. Also important are the mechanical properties of

materials. Thus, reading journals such as the Journal of Material Science and the Journal of

Rheology is very important. Adhesion science also deals with surfaces, so journals such as

Langmuir and the Journal of Colloid and Interface Science often have articles of

importance to the adhesiologist.

There are a number of journals strictly related to the science of adhesion and the

understanding of adhesives. The oldest of these journals is the Journal of Adhesion,

which has been published for more than 25 years. A newer journal is the Journal of

Adhesion Science and Technology. Both of these journals include articles that cover all

aspects of adhesion science and technology. The International Journal of Adhesion and

Adhesives has articles primarily written by European authors. These three journals are

published in English. Other journals important to adhesiologists are published in German

(Adhasion) and in Japanese (The Journal of the Japanese Adhesion Society.) There are also

trade journals that deal with adhesives. The oldest of these is Adhesives Age and a newer

trade journal is Adhesives and Sealants. These journals provide some technical information

but are primarily a source of information about the business of adhesives and sealants.

There are a number of excellent texts in adhesion science. Notable is The Handbook of

Adhesives [7] edited by Skeist. This volume, now in its third edition, is a compilation of

contributed articles describing almost every aspect of adhesive technology. Another

important series of books is the Treatise on Adhesion and Adhesives [8], which has had

several editors. This series of books is important because the articles, even though written

by many authors, are written in greater depth than those in the Handbook. A useful series of

books is entitled Adhesion [9] and Aspects of Adhesion [10]. These books are compilations

12 Introduction

of articles taken from the proceedings of an annual adhesives meeting in the United

Kingdom. The Handbook of Pressure Sensitive Adhesive Technology [11] is similar to the

Handbook of Adhesives but is devoted solely to pressure-sensitive adhesives. The U.S.

Adhesion Society publishes a volume of long abstracts from their annual meeting [12].

There are a few books written by individual authors covering adhesion and adhesives

technology, most notably Kinloch’s Adhesion and Adhesives: Science and Technology [13].

The advent of the Internet has lead to the formation of websites devoted to adhesives. These

websites can be found by searching under the term ‘‘adhesives.’’ However, there are notable

websites including ‘‘This to That’’ (thistothat.com) in which the web surfer can make a

selection of adherends and the site provides a list of adhesives that could work for the

application. ‘‘Adhesives and Sealants.com’’ is a ‘‘full service’’ website in which the web

surfer can find information about adhesive suppliers, processing equipment, as well as new

product information. There is even a website devoted to ‘‘Duck Tape1.’’ ‘‘Duck Tape’’ is a

trademark applied to one type of cloth-backed pressure-sensitive adhesive tape, the name

being derived from a mispronunciation of the actual name of the tape, which is ‘‘duct tape.’’

For the beginning practitioner of adhesive technology, an indispensable tool is the trade

literature provided by adhesive and adhesive raw material manufacturers. In many cases,

detailed descriptions are given of the materials offered as well as starting formulations for

1 ‘‘Duck Tape’’ is a trademark of Manco Tape, Inc.

Table 1.4 Advantages and Disadvantages of Adhesive Bonding

Advantages Disadvantages

No stress concentrations due to piercing of

the adherend

Strength is dependent upon the condition

of the adherend surface

Improved fatigue resistance Durability in adverse environments affected

by surface condition

Lighter weight structures Lack of non-destructive quality control

methods

Ability to join and seal simultaneously Lack of engineering curricula describing

adhesive bonding

Ability to join shock-sensitive substrates Can be more expensive than mechanical

fastening

Ability to join galvanically problematic metals Adhesives are difficult to rework

Can be less expensive than mechanical

fasteners

Possibility of slower processing

Ability to join complex shapes Some adhesives have toxic components

Improved stiffness and improved sound

absorption

Some adhesives have a limited shelf-life

Adhesive can add another function Some adhesives have poor resistance to

crack propagation

1.6 Literature and Other Sources of Information 13

many types of adhesives. For the user of adhesives, trade literature can often provide useful

methodology for the application of the adhesive as well as surface preparation methods.

Trade literature also includes the properties of the adhesive. There is, however, a proviso.

Trade literature often provides data derived from standard tests (many of which are

described in Chapter 3.) It is important to understand the details of the test procedures

used to derive the data before the adhesive user makes decisions based upon trade literature

data.

1.7 Summary

This introductory chapter provides basic definitions used throughout this book, and outlines

the impact of adhesives and adhesive technology on world industry and economy. The

advantages and disadvantages of the use of adhesives to generate assemblies are discussed

as well. A recounting is given in Table 1.4. The chapter ends with a discussion of useful

literature references for the experienced and beginning practitioner of adhesion science.

References

1. Inscription in an ancient Egyptian tomb in Thebes, circa 1500 BC

2. Quote from the Apocrypha, Jesus ben Sirach (Ecclesiasticus, C22)

3. Bommarito, D.,‘‘La tradizione dei ricettari e trattati sui colori nel Mediovo e Rinascimento veneto

e toscano’’, Newberry Library, L.S. Olschki (Ed.), Firenze

4. Schliekelmann, R. J., Trans. JSCM, 5 (1/2), 1 (1979)

5. Lees, W.A., Adhesives Age, 24(2), 23 (1981)

6. ‘‘The 1999 Industry Report’’, Adhesives Age, 42(9), 57 (1999)

7. Skeist, I., ed., Handbook of Adhesives (1990) Van Nostrand Reinhold, New York

8. Patrick, R.L., ed., Treatise on Adhesion and Adhesives, vols. 1–6, (1967–1990), Marcel Dekker,

New York

Minford, J.D., ed., Treatise on Adhesion and Adhesives, vol. 7, (1991) Marcel Dekker, New York

9. Adhesion, vols 1 ff. (1977-) Applied Science Publishers, London

10. Aspects of Adhesion, vols 1–8, (1963–1975) University of London Press, London

11. Satas, D., ed., Handbook of Pressure Sensitive Adhesive Technology, 2nd ed., (1989) Van

Nostrand Reinhold, New York

12. Proceedings of the Annual Meeting of the Adhesion Society, The Adhesion Society, Blacksburg,

VA

13. Kinloch, A.J., Adhesion and Adhesives: Science and Technology (1987) Chapman and Hall, New

York

14 Introduction