Epoxy adhesives introduction

The job of the adhesive formulator has been made particularly difficult by the lack of practical information on the topic. There are only several forums that provide an introduction to adhesive formulating. One such forum is the Adhesive and Sealant Council, which offers short courses on adhesive formulating. There are also a few books that offer information and guides on adhesive formulations.23-27 Information specific to epoxy adhesives is usually found in a chapter or section within the work. There has been no book devoted solely to epoxy adhesive formulations, although several have focused on the more general topics of epoxy resins and their applications.28,29... 

The use of epoxy resins in industry extends back over fifty years since their introduction commercially and they have found an extremely wide range of applications as diverse as coatings and adhesives for electronics to use as matrix materials in aerospace composites. It is the use of advanced composites that is pressuring the advancement of epoxy science and the improvement of epoxy based... 

Saunders, K.J. Organic Polymer Chemistry. An Introduction to the Organic Chemistry of Adhesives, Eibres, Paints, Plastics and Rubbers, 2nd Ed. Chapman and Hall London, Chapter 18, Epoxies, 1988 412-435. 

The introduction of these functionalities on the surface of the aramid fiber resulted in substantial improvement in the fiber-epoxy resin matrix adhesion (about 70%) without a noticeable change in the tensile strength of the fibers. This suggests first that these were possibly covalent and/or hydrogen bonds formed between the fibers and the epoxy resin and that the modification was confined to the surface of the fibers. 

First use of electrically conductive epoxies Premixed, frozen adhesives introduced by Ablestik Laboratories, Epoxy Technology, and Amicon Reduced ion content epoxies and polyimides Introduction of epoxy preforms First high-purity RTV silicone adhesives from G.E. and Dow Coming... 

Epoxy-based thermosets are the most widely used and versatile thermosets. They dominated the reinforcing piping field until the introduction of the vinyl esters, and they are still widely used. They find usage in many applications, including adhesives, coatings, encapsulants, tooling compounds, composites, and molding compounds. Their versatility is due to the wide latitude in properties that can be achieved by formulation. 

Introduction of powdered silieas into epoxies (61) has been found to increase both adhesive and eohesive properties of epoxies. DGEBA epoxy cured with polyethylenepolyamine was tested with powdered silica aerosils which had undergone surface modrficalion with driferent organic compounds. Comparisons were made with silica compounds with surface -Si(0)-OH, -Si(0)-... 

Many formulations are claimed to be capable of absorbing normal residues of rolling oil on steel surfaces, thus reducing the surface preparation requirements as compared with, say, epoxies. As with epoxies, acrylics can be toughened by the introduction of a rubbery phase within the matrix of the adhesive and they are particularly suitable for polymeric adherends because the surface is eompliant. 

As discussed in the Introduction, in addition to hot-melt adhesives, one of the most important forms of adhesives for the future is the waterborne system. In general, an advantage of the waterborne system is that it is free from the solvent-pollution problem. For this reason, we shall describe several new waterborne systems in detail acrylics, modified ethylene-vinyl acetate, polyurethanes, phenolics, epoxies, isocyanates, and tackifiers. Applications of these systems range from PSA s contact adhesives, and laminating adhesives to wood adhesives. 

Epoxy structural adhesives which employ carboxylic polybutadiene/acrylonitrile solid and liquid (CTBN) elastomers as modifiers have increased in number and proliferated in use since their introduction in the mid- 60 s. Such adhesive systems are now used in aircraft, electronics, automotive and industrial bonding operations. In the mid- 70 s, amine-reactive versions of the liquid polymers (ATBN) were issued, thereby offering another way to introduce rubber modification into a cured epoxy network. References are cited which provide detailed discussions of nitrile rubber, carboxylic nitrile rubber and both carboxyl- and amine-terminated nitrile liquid polymers (1-4). ... 

Epoxide resins comprise a broad and important class of adhesives. In the article Epoxide adhesives, an introduction was given to some of the molecules to which the epoxy groups in these materials may be attached. The cure (cross-linking) of epoxies may be achieved... 

The various ways in which epoxies can be toughened by introduction of a secondary phase are discussed in separate articles Toughened epoxide adhesives particle formation prior to cure, Toughened epoxide adhesives precipitation during cure and Toughened epoxide adhesives blend synergy. 

Stainless steel alloys have often proved difficult to bond, but the introduction of the toughened adhesives has alleviated the problem. Both the toughened acrylic and single-part epoxy types will bond these alloys well. Abrasion followed by a solvent wipe appears to be sufficient in most cases, though chemical treatments may be beneficial in more demanding environments. 

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