PRODUCTION OF INFLATION RESIN FILM

摘要

PURPOSE: To stably perform inflation and stretching by cooling the molten resin bubble extruded from an annular molding die to the crystallizing temp. of a resin before heating the same to temp. suitable for the inflation and stretching of the bubble. CONSTITUTION: The outer peripheral surface of the molten resin bubble (e) extruded from an annular molding die (d) is cooled by the air blown out of an air cooling ring 11 and the inner surface thereof is cooled by the air blown out of an inner cooling cylinder 22 to cool the bubble to temp. lower than the m.p. of the resin of the bubble by 15-50 deg.C. Next, the bubble (e) is heated by the hot air blown out of the hot air ring 21 connected to the air cooling ring 11 by the circumferential wall 25 surrounding the bubble (e) and the heated bubble (e) is expanded so that b/a becomes 1.5-15 when the diameter of the bubble (e) at the crystallizing temp. of the thermoplastic resin of the bubble is set to (a) and the final diameter of the inflated bubble (e) is set to (b) to produce an oriented inflation resin film.