PRODUCTION OF AROMATIC CRYSTALLINE THERMOPLASTIC RESIN FILM

摘要

PROBLEM TO BE SOLVED: To produce a cylindrical film excellent in transparency from an aromatic crystalline thermoplastic resin in a descending air cooling system inflation molding method by using a small-sized apparatus reducing film molding cost and achieving easy molding. SOLUTION: In a descending air cooling inflation molding method wherein a resin is melted in an extruder cylinder 2 and a crosshead 3, the molten resin is downwardly extruded from a die 4 to form a bubble 8 which is, in turn, cooled by air and this bubble is flattened by stable plates 6 to be taken up by a pinch roll to form a cylindrical film, the set temp. of the die is set to about the m.p. of an aromatic crystalline thermoplastic resin or less to markedly shorten the interval between the die 4 and the pinch roll 7 as compared with a conventional interval and a cylindrical film excellent in transparency can be inexpensively produced from an aromatic crystalline thermoplastic resin with a melt flow rate of 3-8.