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 permitted under the UK Copyright Designs and Patents Act, 1988, this publication may not be reproduced, stored, or transmitted, in any form or by any means, without the prior permission in writing of the publishers, or in the case of reprographic reproduction only in accordance with the terms of the licences issued by the Copyright Licensing Agency in the UK, or in accordance with the terms of licences issued by the appropriate Reproduction Rights Organization outside the UK. Enquiries concerning reproduction outside the terms stated here should be sent to the publishers at the London address printed on this page. The publisher makes no representation, express or implied, with regard to the accuracy of the information contained in this book and cannot accept any legal responsibility or liability for any errors or omissions that may be made. A Catalogue record for this book is available from the British Library 8 Printed on acid-free text paper, manufactured in accordance with ANSIINISO Z39.48-1992 (Permanence of Paper). 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