Patent ID: 9085124
Filing Date: 2015-07-21
Classification: B32B,Y10T

Abstract:
1. A heat sealable polypropylene resin laminate film having three or more layers, the laminate film comprising: a heat sealable layer having a melting point of not more than 150° C. as a surface layer, the heat sealable layer being a random copolymer or a block copolymer obtained by polymerization of two or more monomers selected from the group consisting of α-olefin monomers having a carbon number of 2 to 10; a substrate layer made of a crystalline polypropylene resin, and having a melting point higher than the melting point of the heat sealable layer; and an intermediate layer disposed between the heat sealable layer and the substrate layer and comprising an α-olefin copolymer containing a cold xylene-soluble fraction in a proportion of not more than 3% by mass and a polypropylene homopolymer, wherein the product of the tensile modulus of elasticity in the machine direction (MD) of the film and in the direction (TD) transverse to the machine direction of the film is 3.1-6.0 (GPa) said crystalline polypropylene resin is a polypropylene homopolymer, said α-olefin copolymer is contained in the intermediate layer in a proportion of 10-70% by weight, and the thicknesses of the substrate layer and the intermediate layer satisfy the following relational formula: wherein x is the thickness of said substrate layer and y is the thickness of the intermediate layer.