Patent ID: 6825280
Filing Date: 2004-11-30
Classification: C08F,C08K,C08L

Abstract:
A propylene block copolymer consisting essentially of the following blocks (a) and (b) and having a melt flow rate of 0.1 to 200 g/10 min:block (a): a polymer block of a homopolymer of propylene or a random copolymer of propylene with a comonomer selected from the group consisting of ethylene and C4-C20 &agr;-olefins, the content of the comonomer being not more than 10% by mole, wherein, the isotactic pentad chain fraction of block (a) is not less than 95%; and block (b): a polymer block of a random copolymer of propylene with at least one comonomer selected from the group consisting of ethylene and C4-C20 &agr;-olefins, the content of the comonomer being 10 to 80% by mole, the average chain length of the comonomer block and the gross average chain length of the comonomer having a relationship represented by formula (I) nb1.5â€ƒâ€ƒ(I) wherein nb represents the average chain length of the comonomer block; n represents the gross average chain length of the comonomer; and wherein the ratio by weight of block (a) to block (b) in the block copolymer is 50:50 to 95:5.