Patent ID: 6624247
Filing Date: 2003-09-23
Classification: C08F,C08J,C08L,C09D,C09J

Abstract:
A polypropylene-based resin film composed of a resin composition (C) comprising:40 to 95% by weight of (A) a propylene-based copolymer selected from the group consisting of a propylene random copolymer (i) of propylene with ethylene and/or &agr;-olefins having 4 or more carbon atoms and a propylene-based copolymer (ii) composed of 1 to 30% by weight of a copolymer component (a) having a content of &agr;-olefins having 4 or more carbon atoms of 1 mol % and less than 15 mol % and an ethylene content of 5 mol % or less, obtained by polymerizing propylene, an &agr;-olefin having 4 or more carbon atoms and further optionally ethylene in a first step and 70 to 99% by weight of a copolymer component (b) having a content of &agr;-olefins having 4 or more carbon atoms of 15 to 30 mol % and an ethylene content of 5 mol % or less, obtained by polymerizing propylene, an &agr;-olefin having 4 or more carbon atoms and further optionally ethylene in a second step or later steps; and 5 to 60% by weight of (B) a polypropylene-based block copolymer (B) having a content of 20Â° C. xylene-soluble component of 5.0% by weight or more, wherein the 20Â° C. xylene-soluble component is a copolymer of propylene with ethylene and/or an &agr;-olefin having 4 or more carbon atoms, having a content of an ethylene unit derived from ethylene and/or an &agr;-olefin unit derived from the &agr;-olefin of 14 to 35 mol %, and wherein the heat seal temperature showing a seal strength of 300 g of the film of the resin composition (C) is lower by 3Â° C. or more than those of respective films of the polypropylene-based copolymer (A) and the polypropylene-based block copolymer (B).