Читать книгу Handbook of Plastics Testing and Failure Analysis - Vishu Shah - Страница 19

Since plastic materials are seldom supplied without the addition of certain additives and fillers, a classification system must be used to avoid confusion. For example, the specification for acetal materials covers three main types of acetal resins: homopolymer, copolymer, and terpolymer. The resin types are subdivided into classes according to the grade descriptions. The group 1, class 1 represents general‐purpose homopolymer acetal resin and group 2, class 3 represents impact modified copolymer acetal resin. Table 1‐1 lists the detailed requirements for acetal materials.