PROPYLENE-ETHYLENE COPOLYMER, ITS PRODUCTION, AND ITS MOLDED ITEM

摘要

PROBLEM TO BE SOLVED: To obtain a propylene-ethylene copolymer having good stiffness and low-temp. heat sealability by selecting a propylene-ethylene copolymer having a specified structure. SOLUTION: This copolymer comprises 0.01-15mol% ethylene units and 99.99-85mol% propylene units and has the following charcteristics: in the chain structure determined by nuclear magnetic resonance spectrometry, the fraction of a triad comprising propylene-ethylene-propylene(PFP) units and the total ethylene unit content (C2) satisfy the relation expressed by formula I; the fraction of a triad comprising three consecutive ethylene units (EEE) and the total ethylene unit content (C2) satisfy the relation expressed by formula II; the ratio of the number of all theα,β-methylene carbon atoms to the total propylene units is 0-1.2mol%; the wt. average mol.wt. is 50,000-1,500,000; and the ratio of wt. average mol.wt. to number average mol.wt. is 1.2-3.8.