PROPYLENE-ETHYLENE BLOCK COPOLYMER

摘要

PROBLEM TO BE SOLVED: To obtain a propylene-ethylene block copolymer having excellent balance between impact strength and rigidity and improved surface hardness. SOLUTION: This propylene-ethylene block copolymer has the heat of fusion (ΔHm) obtained from the different scanning calorimetry(DSC) of its cold xylene insoluble part and frequencyω0 and modulus of elasticity G0 obtained from dynamic melt viscoelasticity measurement satisfyingΔHm>=29.43+1.746 logω0 -1.217logG0 and the ratio of the tanδarea (<=-30 deg.C) of the propylene- ethylene block copolymer to the weight fraction of its cold xylene soluble part satisfying the relation of (tanδarea/weight fraction of its cold xylene soluble part) >=0.6.