Styrene-acrylonitrile copolymer, also known AS resin, is a colorless transparent thermoplastic resin, with high temperature resistance, excellent gloss and chemical medium resistance, as well as excellent hardness, rigidity, dimensional stability and high bearing capacity, based on acrylonitrile and styrene as raw materials by suspension polymerization and obtained, the use of thermal initiator can cause, it can also be obtained by emulsion polymerization. Because of the inherent transparency of the resin, it is used to manufacture transparent plastic products.