Adhesives and sealants (engineered materials handbook, volume 3)

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Adhesives and Sealants (Engineered Materials Handbook, Volume 3) Technical Chairman: Hal Brinson Senior Editor: Cyral A. Dostal Technical Editor: Mara S. Woods

AMS International, USA, 1990, 850 pp + index, $118.00 (non-ASM members), $94.40 (ASM members) The emphasis of this comprehensive reference source is on structural or engineering adhesives and sealants for manufacturing industry application. The intent is to fill a long-standing need for a handbook from which engineers and scientists can obtain definitive information when dealing with the engineering design process and other complex issues associated with their use. In dealing with the multiple disciplines which encompass the science of adhesion, the editors have recognized the need to include chemistry, materials science and solid mechanics as an integrated methodology. It is also pointed out that, in general, adhesives and sealants are different materials performing sometimes overlapping but different functions. The broad range of technical information presented in this volume is divided into 10 major sections. The 97 articles are the collective efforts of over 300 contributing authors and reviewers. Section 1 presents an overview of adhesives and sealant technology and describes the major market and application areas. Included in this section is a detailed description of specifications and standards for adhesives and sealants used in the USA. There is no attempt to correlate this information with European or Asian requirements. The guide to General Information s o u r c e s is more comprehensive and is a useful reference addition. -. Sections 2 and 3 classify and compare the commercially available adhesives and sealants. These materials range from the more commonly used systems such as epoxies and urethanes to advanced materials such as polyimides and polybenzimidizoles. Adhesive modifiers are also described. Sealant materials discussed include polysulphides, water-based acrylics, polyether silicones, fluorocarbons as well as others. For each material type described, information is presented o n chemistry, function, costs, applications, end-use properties, design and processing parameters, Section 4 includes a description of surface analysis techniques to detail adherend surfaces as well as a brief discussion of silane coupling agents and a note indicating the development of water-based systems because of ecological concerns. A comprehensive review of surface preparation techniques for adherends (metals, plastics, composites and ceramics) is also presented which documents the extensive effort that has occurred in this important aspect of adhesion over the last 15 to 20 years. Methods used to test and analyse bonded structures are described in Section 5 and include determination

of mechanical properties, physical characteristics (thermal, electrical) and microstructural analysis. Section 6 covers designing with adhesives and sealants including design considerations for automotive, aerospace and electronic packa~ng applications. A paper titled 'Rating and comparing structural adhesives: a new method' suggests replacing the standard lap shear specimen (ASTM D 1002) with an inverse skin-doubler coupon. This new test geometry is a geometric inversion of the conventional double lap shear joint but is inherently free of all parasitic peel stress effects associated with the standard specimen. The specimen dimensions will need to be adjusted depending on the material to be bonded. The acceptance of the test configuration for shear loading information by the adhesives community will be of interest. Section 7 details the performance of adhesively bonded structures in various service environments, including elevated temperatures, and the effects of moisture,, chemicals, radiation and ageing on the durability of bonded joints. Of particular interest is the paper titled 'Durability assessment and life prediction for bonded joints'. This aspect of adhesion technology is of primary importance in the wide acceptance of bonded structures in the commercial arena. As is pointed out, based on initial strength properties alone it is impossible to describe the real efficiency of the adhesive bonding technique for joining assemblies if they must serve many years at elevated temperatures especially under humid environmental conditions. Sealants are also subject to the same water-related effects as briefly discussed in a following chapter. It is the reviewer's opinion that this facet of adhesion technology must receive greater attention from a fundamental as well as a practical standpoint before widespread acceptance of adhesive joining in the commercial sector is achieved, especially in the USA. Section 8 reviews manufacturing practices associated with adhesives and sealants, including cure controls and curing, and the equipment used for mixing and dispersing materials. Sections 9 and 10 discuss quality control and repair techniques for damaged structures. Covered are raw materials quality concerns, methods for end-product non-destructive evaluation and statistical process control. The numerous steps which must be carefully monitored to achieve successful repair of adhesively bonded metallic and composite structures are presented primarily from the aerospace viewpoint. However, the basic principles described are equally

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important in all areas of adhesive bonding, An increasingly important area which will impact the use and type of both adhesives and sealants, as well as surface treatments, is that of environmental considerations. The development of water-based systems, non-chromate corrosion inhibiting additives and elimination of organic solvents in all aspects of this technology as they relate to use and disposal problems, although mentioned in some instances, has not been adequately addressed by any of the various topics covered. The user of these materials will be well advised to keep abreast of the changes as environmental restrictions and requirements will impact not only the type (composition) but also the methods bv which these systems can be applied. A concerted attempt has been made by the editors to convey the importance of the systems approach to adhesive bonding. This technology is a multi-discipline science and the ultimate acceptance and application of adhesives and sealants will depend upon the appreciation of this concept. To those active in the field this is a useful reference source which provides ready access to the many sciences and technologies involved in these disciplines. R.A. Pike US Regional Editor

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Industrial Packaging Adhesives Edited by K.S. Booth

Blackie, London, 1990, 2 8 2 p p + xiil~ £55.00

Adhesives are widely used in most industries and packaging is certainly no exception. Packaging plays a key role in the distribution of many products, including food and medicines, and, in turn, adhesives frequently play a key role in producing sound packages. The variety of adhesives available has increased considerably in recent years and the appearance of Industrial Packaging Adhesives is ve~' timely. The book is edited by K.S. Booth, Technical Director of Swift Adhesives. He has assembled a ve~, able team of authors to cover adhesives, packaging materials and application techniques. Chapter 1 by A.J. Kettleborough is titled 'The bonding process' and covers the practical aspects of bonding using the complex high-speed packaging now used. Particular emphasis is placed upon the importance of the rheology of the adhesive, the porosity of the substrate and the conditions of compression. In the following chapter by D.M. Lazarus, a very useful comparison of the properties of the different adhesives used is given: these include various natural products, acrylics, EVA hot melts, polyurethanes, poly(vinyl acetate) dispersions and block copolymers (sB and Sl). In chapter 3, ICW. Allen discusses the various theories of adhesion. There follows an excellent chapter by B. Vyse and P. Franlding on the testing of adhesives and their performance in structures formed with packaging materials. There follow five authoritative chapters on the application of adhesives to form a wide variety of packaging products. Chapter 10 by T.B. Coggin deals with economic aspects of adhesive selection. The author covers not only the cost of the adhesive, but also application costs and deals with the cost implications of health and safety factors. In the final chapter, L.J. Kuzma considers the future for packaging adhesive systems. Emphasis is placed on the impact of environmental legislation, e.g., on solvent emission and the disposal of solid waste. Included in the book are two useful appendices, one on Hearth and Safety and the other a glossary, of terms used in the various chapters. Overall the book is well presented and clearly illustrated. Industrial Packaging Adhesives provides a useful addition to the range of books on adhesion and adhesives and is strongly recommended to those involved in packaging technology.

D.M. Brewis University of Technology, Loughborough, UK