Coatings and other applications of epoxy resins

Abstract

The current use pattern for epoxy resins is similar to that suggested by Lee and Neville in 1967 who estimated consumption as coatings 55%, composite matrices 20%, castings 10%, adhesives 5% and miscellaneous 10%. These figures may be compared with the 1990 and 1991 estimates given in chapter 1, Table 1.1, even though the categories are not identical. Lee and Neville (1967a) pointed out that there are difficulties in obtaining exact consumption estimates. However, the main difference is that coatings have a slightly lower share of the epoxy market. Epoxy resins are usually more expensive than their rivals, such as phenolic resins for coatings or laminates. Therefore, epoxy resins find application because of their superior properties, which include both processing and those of the cured resin. The processing is convenient since it is possible to formulate compositions with the required rheological properties, such as low viscosity, and there is also a wide choice of hardeners so that it is possible to cure at ambient as well as elevated temperatures. Because epoxy resins can be cross-linked without the formation of low molecular weight products, volatiles are not evolved during cure, and the resins have only a relatively low shrinkage during curing. Their mechanical and electrical properties are superior to other resins and they have good heat and chemical resistance.