Composite film and packaging material of polypropylene base and surface polymer composition

摘要

A packaging material which is capable of packaging an article(s) in a closely fitted and tightly sealed state and consists essentially of a composite film stretched at least in one direction, said composite film comprising a base film and a surface film provided on at least one surface of the base film and having certain specific shrinkage characteristics, said base film being made of a resin composition comprising a propylene polymer, and said surface film being made of a polymer composition comprising at least two of (A) a copolymer of propylene and ethylene in a weight proportion of 99.5:0.5 to 90:10, (B) a copolymer of propylene and an alpha -olefin having 4 to 10 carbon atoms in a weight proportion of 70:30 to 95:5 and (C) a copolymer of butene and any other alpha -olefin having 2 to 10 carbon atoms in a weight proportion of 70:30 to 99:1, each of the copolymers being in an amount of 10 to 90% by weight on the total weight of the copolymers.