Patent ID: 7875682
Filing Date: 2011-01-25
Classification: C08F,C08L

Abstract:
1. A propylene block copolymer obtainable by a multi-step polymerization in the presence of a metallocene catalyst supported on a carrier comprising: a former step for producing a propylene homopolymer component, or a propylene copolymer component (hereafter referred to as PP) composed of propylene and at least one kind of a comonomer selected from the group consisting of ethylene and a C a latter step for producing a copolymer component (hereafter referred to as CP) composed of propylene and at least one kind of a comonomer selected from the group consisting of ethylene and a C characterized by satisfying the following requisites (1) to (4): Requisite (1): Content of CP in the propylene block copolymer is from 45 to 99% by weight Requisite (2): Polymerization ratio of the comonomer in CP is from 30 to below 100% by mole Requisite (3): Weight average molecular weight of CP is from 100,000 to 2,000,000 Requisite (4): Ratio of amount of a component with a molecular weight of equal to or less than 5000 (M≦5000), by measurement with gel permeation chromatography (GPC), is equal to or less than 2.0% by weight of the total.