Structural Adhesives: Directory and Databook

422 Pages·1996·52.54 MB·English

by  Bob Hussey

STRUCTURAL
ADHESIVES
DIRECTORY AND DATABOOK
Compiled by Bob Hussey and Jo Wilson
RJ Technical Consultants
Charente Maritime
France
CHAPMAN &. HALL
London· Weinheim . New York· Tokyo· Melbourne· Madras
Published by Chapman & Hall, 2-6 Boundary Row, London SEt 8HN, UK
sm
Chapman & Hall, 2-6 Boundary Row, London 8HN, UK
Chapman & Hall GmbH, Pappelallee 3,69469 Weinheim, Germany
Chapman & Hall USA, 115 Fifth Avenue, New York, NY 10003, USA
Chapman & Hall Japan, ITP-Japan, Kyowa Building, 3F, 2-2-1 Hirakawacho, Chiyoda-ku, Tokyo 102,
Japan
Chapman & Hall Australia, 102 Dodds Street, South Melbourne, Victoria 3205, Australia
Chapman & Hall India, R. Seshadri, 32 Second Main Road, CIT East, Madras 600 035, India
First edition 1996
© 1996 Chapman & Hall
ISBN-13: 978-0-412-71470-2 e-ISBN-13: 978-1-4613-1203-1
DOl: 10.1007/978-1-4613-1203-1
Apart from any fair dealing for the purposes of research or private study, or criticism or review, as
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A Catalogue record for this book is available from the British Library
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PREFACE
The overall aim of this book is to aid the adhesive selection I:J Part Three -Data: Consists of nine main sections,
process. It provides concise, relevant technical data and organised alphabetically by base-chemical constituent;
details of sources for a wide range of synthetic polymer often used by manufacturers to class their products
based adhesives used for structural bonding in many and one basis for users to select an adhesive. A
industry sectors. further section contains miscellaneous structural
adhesives. Each section contains:
The increasing use of adhesive bonding for significant load
bearing applications reflects its advantages over traditional • Comparison Tables -At-a-glance comparison of
joining methods; particularly in the area of rapid, low-cost, adhesive properties and characteristics.
automated production processes. With recent developments • Data sheets - Individual data sheets for each of the
in materials technology and processing there are now many products.
materials that can only be successfully joined using
I:J Part Four -Appendices:
adhesives. There is also an increasing tendency for new
adhesives to be developed in co-operation with materials • A -Test Specifications and Standards.
producers or major industrial users.
• B -Terminology: Definitions.
For the design of bonded jOints, basic information is • C -Glossary: Multilingual key words.
required on available adhesives and their characteristics.
• D - Conversion Factors.
This provides an indication of the capabilities of potential
adhesives and also serves as a basis of comparison I:J Index:
between commercially available products. However, finding
and acquiring this information can be a difficult and very • Product codes (giving manufacturer & type).
time consuming process. This book will greatly simplify this • Manufacturers and adhesive types.
process for the reader.
The number and variety of commercially available adhesives Note
are now very large and continue to increase. Adhesive
manufacturers are active in developing new formulations to
The characteristics and adhesive property data in this book
meet a widening demand, and in modifying current
have been compiled from technical data sheets obtained
formulations to meet new environmental legislation. This is
from manufacturers, to whom we extend our gratitude. Great
reflected in the reduction or removal of known hazardous
care has been taken to ensure that the information is
chemicals, solvents and asbestos fillers and a general trend
accurately represented here, but no responsibility can be
towards water-based adhesives.
taken for errors or omissions.
Users of adhesives must determine the suitability of
For this first edition we have tried to include the largest
particular products for each intended use. Most
possible number of manufacturers, suppliers and products.
manufacturers will provide assistance with this. The review
Inevitably some will have been missed, so any comments on
section of this book emphaSises that all aspects of the use
alterations or additions would be very useful. The final page
of an adhesive should be fully evaluated before finalising a
of the book shows how to contact us.
design.
Acknowledgements
THE STRUCTURE OF THIS BOOK
We would like to thank Roger Davies for acting as our leg
The book is divided into four main parts:
man in difficult circumstances, and Dave Bashford for
I:J Part One -Review: Provides a broad introduction to bearing an endless stream of enquiries with fortitude.
the subject of adhesives and adhesive bonding: Thanks are due to many others who helped by replying
promptly to our queries.
I:J Part Two - Directory: Contains comprehensive
Thank you.
listings of manufacturers, their product types,
tradenames and contact details for all those included
in this edition.
CONTENTS
PREFACE iii BASIC DESIGN OF BONDED JOINTS 9
THE STRUCTURE OF THIS BOOK Types of Joints 9
Surface Preparation 10
Note
Degreasing 10
Acknowledgements
Mechanical Treatments 11
CONTENTS iv Chemical Treatments 11
Primers 11
Part 1: REVIEW 1 Bond Performance 11
INTRODUCTION 1 Analysis 11
Testing 12
BASIC CLASSES OF ADHESIVES 1
HEALT H & SAFETY ASPECTS 12
Acrylic Adhesives 2
FURTHER READING 13
Anaerobic Adhesives 2
Cyanoacrylate Adhesives 2 Books 13
Epoxy Adhesives 2 Journals 13
Imide-based Adhesives 3 ANALYTICAL DESIGN TOOLS 14
Bismaleimides 3
Part 2: DIRECTORY 15
Polyimides 3
Phenolic Adhesives 3 MANUFACTURERS' PRODUCT RANGES 16
Polyurethane Adhesives 3 TRADE NAMES & STANDARD PRODUCT
Silicone Adhesives 4 CODES 18
Thermoplastic Hot-Melt Adhesives 4 MANUFACTURERS & SUPPLIERS -
Miscellaneous Adhesives 4 ADDRESSES 21
Cyanate Ester 4 MANUFACTURERS & SUPPLIERS -
Poly Vinyl Acetate 4 COUNTRIES 52
Plastisols 5 USEFUL NAMES & ADDRESSES 58
Ceramic-based 5
Adhesives & Sealant Manufacturers
ADHESIVES USED IN VARIOUS Associations 58
INDUSTRIES 5
Other Trade & Research Organisations 59
GUIDE TO ADHESIVE SELECTION 6 Standards Organisations 62
Factors to be Considered 6
Part 3: DATA 63
Materials to be Bonded 6
Joint Design 7 PRESENTATION OF DATA 63
Adhesive Characteristics 7 KEY 64
Cost 8
ACRYLIC ADHESIVES 66
Application Method 8
Comparison Table 67
Health & Safety Requirements 8
Data Sheets 69
Cure Factors 8
ANAEROBIC ADHESIVES 92
Appearance 9
Service Environment 9 Comparison Table 93
Viscosity Guide 9 Data Sheets 95
Contents v
Standards by Industry Sector & Use 385
CYANOACRYLATE ADHESIVES 118
Terminology 385
Comparison Table 119 Aerospace 385
Data Sheets 122 AECMA 386
EPOXY ADHESIVES 149 Space Agencies 386
Comparison Tables 150 Aircraft Manufacturers' 386
One-Part Pastes 150 US Federal Specifications 386
Two-Part Pastes 151 Construction/Building 388
Films 155 Metal Bonding 388
Data Sheets 157 Plastics Bonding 389
IMIDE-BASED ADHESIVES 235 Shoe-Making 390
Wood & Wood Products 390
Comparison Table 236
Specifications -Types of Adhesives 391
Data Sheets 237
Surface Preparation 391
PHENOLIC ADHESIVES 241 Processing & Usage 392
Comparison Table 242 Chemical Properties 392
Data Sheets 243 Electrical Properties 392
POLYURETHANE ADHESIVES 247 Physical Properties 392
Comparison Table 248 Mechanical Properties 393
Data Sheets 252 Environmental Properties 395
Miscellaneous 396
SILICONE ADHESIVES 299
Pressure Sensitive 397
Comparison Table 300
Sources 397
Data Sheets 302
Appendix B -GLOSSARY 398
THERMOPLASTIC HOT- MELT ADHESIVES 322
Appendix C - MULTILINGUAL
Comparison Table 323
VOCABULARY
Data Sheets 325
English-French-German-Italian-Spanish 401
MISCELLANEOUS ADHESIVES 355
Appendix D -CONVERSION FACTORS &
Comparison Table 356 UNITS 405
Data Sheets 358
Introduction 405
PART 4: APPENDICES 377 Conversion Factors 406
Multiple Units 406
Appendix A -SPECIFICATIONS &
STANDARDS 378 INDEX 407
Introduction 378 PRODUCT CODES I NAMES 407
ASTM Standards 378
SUPPLIERS & PRODUCT TYPES 415
British Standards 381
DIN Standards 382
CALL FOR CONTRIBUTIONS
EN Standards 383
ISO Standards 384
NF Standards 384
Part 1: REVIEW
INTRODUCTION bonding has become an established production and
assembly technique. Here, drilled holes for mechanical
fasteners may affect the inherent strength of the material
The adhesive bonding of materials has been found in all of whereas bonded joints do not. The structural uses of
the ancient civilisations. The adhesives used were naturally adhesives are now very diverse, from the bonding of shoe
occurring substances; gum arabic, bitumen, egg, starch uppers to soles to the assembly of aerospace structures and
pastes, protein from cheese or blood and gelatine from all points in-between.
animal parts; hoof, horn and bones. These natural
adhesives remained dominant until the twentieth century, This book concentrates on those synthetic adhesives which
but, although providing adequate strength, they did suffer are required to have structural characteristics, i.e. they
from environmental degradation and had severe perform a significant load-bearing function within their given
shortcomings when bonding synthetic materials and metals. application. Classed by base-chemical constituent (a
common method used by manufacturers to describe their
The demand for adhesives with improved durability, together products), and with comprehensive cross-referencing, each
with advances in polymer chemistry, saw the first range of section of this book provides information and property data
synthetic adhesives becoming commercially available in the for comparison purposes. Details of manufacturers world
1950's. Many of these offered a considerable improvement wide and their product ranges are listed in the directory.
over natural adhesives, but still had some drawbacks - such
as unstable curing and inconsistent bond strength. Great
improvements were obtained by chemical modifications to
the adhesive formulations. At the same time adhesion BASIC CLASSES OF ADHESIVE
studies showed the great importance of surface preparation
in achieving consistent bond strengths.
The term 'Structural Adhesive' covers many basic chemical
In recent decades the number and variety of commercially classes of adhesives. Also, within chemical classes there
available adhesives has increased rapidly, and adhesive may be both structural and non-structural adhesives, e.g.
bonding has become a common joining method in most not all polyurethane adhesives are structural; some are
industry sectors. This is partly a result of the use of new sealants having some adhesion characteristics. As such,
materials and production processes, and partly a response information is restricted to those types of adhesives used, or
to the economic and engineering benefits to be gained from promoted for use, in structural applications. In some cases,
replacing traditional mechanical joining methods, e.g. the dividing line between sealant and adhesive becomes
increased production rates, reduced machining operations, 'blurred'. For example; silicone-based materials may be
reduced corrosion. To ensure that the required bond used as adhesives or as sealants. In many applications, the
performance (strength and durability) is achieved, design ability of an adhesive to also 'seal' a joint against the
and testing procedures have evolved. The design of bonded environment is an important advantage, avoiding leakage or
joints is normally evaluated by a combination of analysis crevices where corrosion could occur.
and testing. These are often specific procedures generated
within an industry sector. Test standards and specifications What follows is a broad overview of the characteristics of
for adhesive characteristics are now numerous. the chemical classes of structural adhesives described in
this book. Technical terms have been kept to a minimum
Many current production materials can only be successfully such that it serves as an introductory guide rather than an
joined using adhesives. The emergence of fibre-reinforced in-depth description of the complexities of adhesive
plastics as structural materials has meant that adhesive formulation.
2 Review
Acrylic Adhesives Higher strength versions may be used for the permanent
fixing of rotating components, e.g. gears and bearings -
avoiding the need for machined keyways and preventing
Acrylic-based polymers were first produced in Germany in
mechanical fretting and crevice corrosion problems.
1901. Subsequent work has produced a range of acrylic
Anaerobics are also widely employed in the assembly of flat
based adhesives with the following general features:
load-bearing panels where ease of use and rapid curing has
[J Adhesion to a variety of substrates. benefits over the more traditional classes of adhesives.
[J Water resistance. Other formulations may be used for the filling and sealing of
surface imperfections in manufactured parts and for gasket
[J Durability. jointing. Adhesive primers, heat, metal ion catalysts and UV
radiation can all be used to accelerate curing.
[J Flexibility (with modified formulations).
Cl Good low temperature properties.
Cyanoacrylate Adhesives
Cl Excellent optical properties.
[J Low toxicity. Although the first alkyl cyanoacrylates were synthesised in
1947, they only appeared as adhesives in 1958. The first
The main forms and uses of acrylic adhesives are:
generation adhesives had some limitations because of
Cl Water-borne emulsions and solvent solutions - used in
brittleness (leading to poor tolerance to impact, peel, heat
non-structural applications, such as pressure-sensitive
and thermal cycling). The cure was very sensitive to the
tapes and labels. Information on these types, of which
nature of the surface to be bonded (porous and acidic
there are many, is not given in this book. Those
surfaces were difficult). Available moisture also greatly
specifically for wood bonding are included.
affected curing. The adhesives showed poor gap filling,
[J 100% solid reactive adhesives - used in structural 'fogging' of nearby shiny or transparent materials and had a
bonding applications in the engineering industries for pungent odour. Many of these problems have now been
the bonding of metals and non-porous plastics. solved by modifying the formulations. Toughened
cyanoacrylates with rubbery additions have much improved
Engineering acrylic adhesives are two-part systems which,
mechanical properties. The addition of surface activating
when mixed or activated, polymerise (cure) to form an
agents has reduced the cure sensitivity. Gelled varieties are
impact-resistant plastic layer which is well adhered to the
now available which improve the handling and gap filling
surfaces of the adherends. The activator for the curing
characteristics. Their main features are:
process may be a chemical (either mixed with the adhesive
or applied to the adherend surfaces prior to the adhesive), [J One-part adhesive.
or, for some varieties, UV or electron-beam radiation. The [J 'Instant' bonding - curing achieved under ambient
toughened or modified engineering adhesives have been conditions (no additional heating required). Cure is
widely used since the 1980's in vehicle construction, wood to activated by atmospheric moisture.
metal bonding, aerospace applications, panels and
computer equipment. [J Bond a wide variety of adherends.
Their use for joining small parts is now widely accepted in
many industries, particularly in applications where an
Anaerobic Adhesives
'instant' bond is needed, avoiding the need for clamping,
heating, etc.
These adhesives were first produced in the 1940's. Their
main feature being that they cure rapidly in the absence of Cyanoacrylates are now widely available for domestic use.
oxygen to produce strong bond, i.e. the conditions found When first introduced, their low viscosity, together with the
between adherends and in crevices. other features are: unusual phenomenon of an 'instant' adhesive and good
[J Room temperature curing. adherence to skin, resulted in some users finding
themselves stuck to the parts. With public experience and
[J Chemical resistance to a variety of substances, e.g.
new formulations, this problem has diminished.
oils and solvents.
[J Low shrinkage.
Epoxy Adhesives
Cl Contain no solvents.
[J Excess adhesive can be easily removed from adjacent Epoxy-based adhesives were first introduced in the 1950's.
surfaces. Since then they have become widely used, particularly in the
aerospace, vehicle and boat building industries, for
Early anaerobic adhesives suffered from unstable curing,
applications requiring high strength and endurance.
mainly as a result of the problems of maintaining the
The main features of epoxy-based adhesives are:
oxygen-level in the liquid adhesive prior to its use. This was
subsequently solved by modification of formulations. Current [J Good adhesion to many different substrates.
versions no longer suffer from this problem, or the [J A range of mechanical properties: depending on
associated need for highly-controlled storage. formulation and curing.
One of the most important applications for anaerobics is the [J A wide range of cure characteristics.
thread-locking of mechanical fasteners which might loosen
[J Low shrinkage.
with vibration. A range of strengths are available to allow
disassembly and use on a wide range of thread diameters. Cl No by-products evolved during cure (except with
phenolic modified types).
Review 3
In addition to the various curing agents used, elastomeric There are two main classes of polymerisation reaction
modifiers have been added to improve peel strengths and (curing mechanism) for these adhesives and their
moisture resistance. Newer varieties have been formulated processing characteristics are different:
to be 'tougher', i.e. having improved impact resistance and D Condensation: These were the first type to be
higher fracture surface energies, whilst retaining stiffness introduced and can withstand temperatures of 260°C
and hot strength. Epoxy-based adhesives are used to -315°C. Volatiles (often water molecules) are
extensively for bonding metals and fibre-reinforced plastic evolved during the cure, so processing is normally
materials (FRP). Many FRP materials use epoxy-based carried out under vacuum to remove these from the
resins as the matrix phase, showing an obvious curing polymer. The cure temperature is typically
compatibility with these adhesives. -177°C followed by a post-cure at -290°C.
Epoxy adhesives may have a variety of cure temperatures, D Addition: The first stage of curing, carried out at
from room temperature (RT) up to 175°C, and are available -200°C, is a 'condensation' type. At the end of this the
as pastes (one or two-part) or films. Two-part, RT curing adhesive becomes a thermoplastic. A higher pressure
varieties are widely available for domestic use. and temperature stage (-290°C) is then used to
consolidate the bondline and finalise the cure. These
Although epoxy adhesives represent a relatively small adhesives have a slightly lower oxidation resistance
proportion of the total adhesives market, there are perhaps than the 'condensation' types, which limits their service
more varieties of formulations available from more sources temperature to -260°C.
than for any other adhesive class. For many years, they
have dominated the high-performance adhesives market,
Phenolic Adhesives
but the desire for increased service temperatures has led to
the development of new adhesives based on imide polymers
(Polyimides and Bismaleimides). Phenolic resins are synthesised from phenol (or phenol
substitutes) and formaldehyde. They first appeared in the
early 1900's, since when Bakelite has been a widely
Imide-Based Adhesives
recognised name. Phenolic-based formulations are used as
adhesives for structural applications, notably for wood
This term is used within this book to group together products. Their main features are:
Bismaleimide and Polyimide adhesives. Both types evolved D High mechanical strength.
from the development of resins for fibre-reinforced
D Good solvent and water resistance.
composites. BMI and PI composites have higher
temperature resistance than those based on epoxy resins. D High thermal stability.
Therefore an adhesive compatible with both the polymer
D Flame retardant.
matrix and the higher service temperatures was required.
There are currently few commercial products available. The The major uses of phenolic adhesives are:
majority of these are designed for aerospace composite D Wood, plywood, chip- and block-board manufacture,
bonding applications, although metal bonding is also laminated beams and the joints between them.
possible.
D Abrasives -bonded abrasives (grinding wheels),
coated abrasives (sand paper, discs and belts).
Bismaleimides
D Foundries - binders for moulding sands.
The main features of bismaleimide adhesives are:
D High-temperature capability (200°C to 230°C). D Friction composites - binders for brake linings,
clutches and automatic transmissions.
D Excellent electrical properties, e.g. high-energy radome
applications. D Fibre-reinforced composite manufacture -with all of
the major types of reinforcing materials. Used widely in
D No volatiles evolved during cure (pure addition
the electronics industry, structural panelling (often
reaction), which simplifies processing and reduces
flame retardant applications) and decorative laminates
porosity.
for furniture.
D Poor peel resistance, owing to their stiffness. Phenolics are also used as additives in other synthetic
Modified BMI adhesives are now available with improved adhesives, e.g. epoxies and 'contact' neoprenes, where they
peel resistance. lend some level of the above properties to the adhesive.
Polyimides Polyurethane Adhesives
The main features of polyimide adhesives are:
D High-temperature capability (up to 300°C). This class contains both polyurethane-and isocyanate
based adhesives. The development of polyurethane
D Excellent electrical properties, e.g. radome
adhesives is credited to the research of German scientists
applications.
during World War II. Their main features are:
D Evolution of volatile materials during cure, so D Good adhesion to a variety of substrates.
extraction or high processing pressures are needed.
D Good chemical resistance to oils, solvents, etc.
Polyimide adhesives are mainly available as films, although
some formulations are beginning to be available as pastes. D Tough, flexible bonds.
4 Review
[J Available in many forms, e.g. liquids, dispersions, The general features and advantages of hot-melts,
films, powders, etc. compared with conventional adhesives, include:
Some of these products are described as 'hot-melt' or 'melt [J Rapid setting times (increased production rates).
applied', which may be misleading. They are provided as
[J A wide number of formulations available with different
solids which must be heated to a molten state to be applied,
properties, e.g. melting temperature and viscosity.
however, the final properties are obtained by a subsequent
Most manufacturers will tailor properties to meet
room-temperature moisture curing mechanism rather than
particular applications. Grades may also be blended
just solidification (true thermoplastics). Within this book,
by the user.
such products are classed in the polyurethane section, not
as thermoplastic hot-melts. [J Solvent free.
[J Available in many solid forms, e.g. pellets, powders
The industrial uses of polyurethane adhesives are many and
and granules, sheets and films, filaments, rods and
diverse. The major market sectors for structural applications
billets.
are in the manufacture of furniture and in the construction,
footwear and vehicle industries. [J Ease of use (automated dispensing equipment or
hand-held glue guns).
Silicone Adhesives [J No special storage conditions needed, i.e. long-term
stability at ambient temperatures.
Silicones are synthetic polymeric materials which may be Within the 'hot-melt' class, the main types and base
formulated to have a very wide range of properties. All have materials can be grouped as:
a basic polysiloxane structure, giving them a combination of [J Low-performance - based on Polyolefin or ethylene
organic and inorganic chemical properties. These properties based materials, e.g. EVA. These are widely used in
have made them of interest for adhesive and sealing the packaging industries. EVA is well-established for
applications. Their main features are: paper-based adherel1ds, e.g. packaging, book-binding
[J A wide range of possible viscosities. and textiles, with some, mainly semi-structural, uses in
furniture manufacture.
[J Good flexibility.
[J High-performance - based on Polyesters or
[J Very good resistance to high and low temperatures
Polyamides. These are a development of the high
(-115°C to +265°C).
performance hot-melts for synthetic fibres, e.g. Nylon
[J Resistance to UV and IR radiation. and Polyester. The fibre polymers melt at too high a
temperature and set too rapidly to be used directly as
[J Resistance to oxidation. adhesives. This has led to the development of other
Depending on the formulation, curing is by: forms (co-polymers) to be used as adhesives. These
have good adhesion to a variety of surfaces, including
[J Exposure to atmospheric moisture (one-part systems),
wood, textiles, plastics and metals.
or
Some polyurethane adhesives are applied in a molten form
[J Addition of cross-linking agents (two-part systems).
but then undergo a moisture or reaction cure. This type
Some have an acetoxy cure mechanism, releasing acetic (often called hot-, warm-melt or melt-applied) are not
acid during cure which may cause corrosion problems. included in the thermoplastic hot-melt section. (See:
Others are described as 'neutral' curing. Most are cured at Polyurethane)
RT for several days (RTV - Room Temperature
Vulcanisation), although higher temperatures may be used
Miscellaneous Adhesives
to reduce cure times.
Silicone adhesives/sealants have good resistance to water The 'Miscellaneous' section in this book gives information on
and weathering (UV and chemical attack). This, coupled other classes of adhesives used for structural bonding and
with their high flexibility and good gap-filling makes them products of unknown chemical base. Some of these are
suitable for many applications in the construction, marine recent developments with a limited number of commercially
and vehicle assembly industries. available products, e.g. Cyanate Esters. The materials
included have a veiY wide range of characteristics and
applications. A brief description of some of them is given
Thermoplastic Hot-Melt Adhesives
here.
All thermoplastic adhesives require heating in order to melt Cyanate ester
the polymer, hence the name 'hot-melt'. Unlike the majority
These are a recent development for bonding high
of structural adhesives, there is no chemical curing reaction.
performance, fibre-reinforced composites with a cyanate
Initially based on natural substances, synthetic hot-melt
ester resin matrix. They are intended for aerospace
adhesives first became available in the 1950's. A great
applications requiring improved high temperature
many polymers exist as thermoplastics, providing a wide
performance and moisture resistance.
range of pokntial hot-melts. Each adhesive formulation
contains a cocktail of compounds to modify the properties.
Poly vinyl acetate
These include tackifiers to promote adhesion and waxes to
reduce viscosity and cost. First available commercially in the 1930's, PVA became a
widely accepted substitute for the cheaper hide-based glues
in the 1940's. Easier to use and adaptable to automation,
Review 5
PVA first found uses in packaging and paper converters. of the liquid carrier to cause gelling. A strong solid-phase is
This was followed by the introduction of the 'white' glues for then produced on cooling. These adhesives are generally
wood products. Other applications include textile bonding, thought of as semi-structural, e.g. low resistance to peel and
building and construction industries. cleavage, creep under prolonged static loads, but they may
Note: The term PVAC is used within this book to cover PVA show reasonable resistance to cyclic loading.
and other co-polymer forms.
Plastisols are used in automotive assembly for lower
The main advantages of PVAC include: performance applications, e.g. the bonding of panel
[J Adhesion to a wide variety of surfaces - cellulose reinforcements. An advantage here is that they are capable
containing (paper and wood) and formulations for of bonding oily surfaces; some absorb the oil film during
bonding plastic films and metal foils to paper and cure, reducing the required surface preparation. Also, the
wood. adhesive may be formulated such that it cures during the
paint-stoving process.
[J High cohesive strength and toughness.
[J A range of viscosities - applied by roller, spray or Ceramic-based
extrusion. There are many formulations of inorganic adhesives. Often
they are one-or two-part paste or cement-like compounds
[J Rapid setting - in emulsion types, the loss of a small
for specific applications. The general areas of use are:
amount of the water initiates rapid setting.
[J Very high temperatures, i.e. 400 to -1600°C.
[J A wide range of possible formulations - often including (Exceeding the capabilities of any polymer-based
modifying agents such as plasticisers, tackifiers, materials).
wetting agents, setting agents, biocides, extenders and
additions to alter the viscosity or rheology. [J Very aggressive chemical environments, e.g. the
construction of acid reservoirs.
[J A range of formulations showing differing solvent and
The composition of the ceramic phase largely dictates the
water resistance.
temperature and chemical resistance of the adhesive.
[J Good mechanical stability and machining
characteristics. Typical applications include the bonding of:
[J Thermal insulation materials, to themselves or to
[J Resistance to degradation by oxygen, ozone and UV
metals, glass or wood.
radiation.
[J Refractory materials, e.g. kiln and furnace assembly.
[J Low toxicity - some approved for use in food
packaging. [J Foundry moulds and other liquid metal handling
components.
Other adhesives included in this group are:
[J Poly vinyl acetals -formulated from the chemical [J Teeth (dental cement) and bone.
components of PVA and polyvinyl alcohol (PVOH
also an adhesive in it's own right).
[J Poly vinyl butyrals -which have good adhesion to
glass. These are widely used in laminated 'safety' ADHESIVES USED IN VARIOUS
glass products, e.g. windscreens and architectural
INDUSTRIES
shaped-glass.
Plastisols Table 1 summarises the main industries using adhesives in
These are based on dispersions of plasticised PVC and cure structural applications and the classes of adhesives which
on heating. The curing mechanism involves the absorption are most frequently used.
Table 1 Adhesives Use by Industry Sector
Acrylic Anaerobic Cyanoacrylate Epoxy Imide Polyurethane Phenolic PVAC Silicone Hot-melt
• • • • • • •
Conslruction
• • • •
Textile
• • • • •
Packaging
• • • •
Wood Products
• • • • • •
Automotive
• • • • • •
Electrical
• • • • •
Furniture
• • • •
Aerospace