Patent ID: 6686055
Filing Date: 2004-02-03
Classification: B32B,C08L,Y10S,Y10T

Abstract:
A polypropylene composite film comprising:(I) a crystalline polypropylene layer, and (II) a propylene/1-butene random copolymer layer laminated on at least one surface of the crystalline polypropylene layer (I): said propylene/1-butene random copolymer (II) having the following properties: (1) the copolymer contains 60 to 85% by mol of constituent units derived from propylene and 40 to 15% by mol of constituent units derived from 1-butene, (2) the intrinsic viscosity, as measured in decahydronaphthalene at 135Â° C., is in the range of 1 to 5 dl/g, (3) the molecular weight distribution, Mw/Mn, as determined by gel permeation chromatography, is not more than 3, and (4) a parameter B value, which indicates the randomness of the copolymer, is in the range of 1.0 to 1.5, wherein B=P12/(2P1Â·P2) whereP1 is a first monomer content fraction, P2 is a second monomer content fraction, and P12 is a proportion of the first monomerâ€”second monomer sequences to the total diad sequences.