RETORT FOOD-WRAPPING FILM AND ITS PRODUCTION

摘要

PROBLEM TO BE SOLVED: To obtain a retort food-wrapping film having good impact resistance in low temperature and good at appearance, blocking resistance and heat sealing property. SOLUTION: This film is obtained by following steps; a block copolymer is obtained by polymerization of polymer part (A-component) mainly composed of propylene in the absence of any inert solvent in the first step and gas phase- copolymerization of copolymer part (B-component) of propylene and ethylene in the second step where ethylene content is 20-50 wt.%, the resultant block copolymer is melt-kneaded to obtain a composition and the resultant composition is formed into a film. The film satisfies following properties: (1) the xylene- soluble part of the film is 8-25 wt.% at 20 deg.C, (2) the intrinsic viscosity of the xylene-soluble part of the film is >=2 dl/g, (3) the haze of the film is >=45%, and (4) the fish eyes having >=200μm diameter is <=100 per 1 m2.