By virtue of its enormous benefits, such as light weight, outstanding toughness, easy molding and low cost, plastic is gaining more and more popularity in modern industry and the production of daily necessities, because it is an ideal substitute for glass. Especially, in the fields of optical devices and the packaging industry, it has witnessed an exceptionally rapid development. However, due to the fact that such plastic materials are required to be extremely transparent(clear), with great abrasion resistant and impact resistant features, a great deal of effort is needed in the aspects of plastic ingredients, as well as the technology, equipment and molds throughout the entire plastic injection molding process, so as to make sure that these glass substitute materials (hereinafter referred to as transparent plastics) possess an outstanding surface finish, thus meeting the application requirements.
Currently, the commonly used transparent plastic materials on the market include polymethyl methacrylate (commonly known as acrylic or acrylic glass, abbr. PMMA), polycarbonate (abbr. PC), polyethylene terephthalate (abbr. PET), transparent nylon, acrylonitrile-styrene copolymer (abbr. AS) and polysulfone (abbr. PSF), etc., among which the 3 most commonly used ones are PMMA, PC and PET.