HIGH MOLECULAR-WEIGHT POLYPROPYLENE HAVING BROAD MOLECULAR-WEIGHT DISTRIBUTION

摘要

PPROBLEM TO BE SOLVED: To provide an improved composition for molding capable to produce a pipe having low brittleness and smooth surface, further having high toughness, good stiffness and excellent creep fracture strength by an ordinary machine tool. PSOLUTION: This invention relates to a high molecular-weight copolymer comprising ethylene unit and propylene unit, having 1-10 wt.% ethylene content, and having a melt flow rate (MFR) (230/5) of 5 dg/minute and molecular weight distribution MSBw/SB/MSBn/SBof 6-20. This invention is also a process for producing the copolymer in the presence of a catalyst, (B) an organo-aluminum compound and (C) an organo-silicon compound by 2 polymerization reaction processes and in the first process, a suspension medium is simultaneously a monomer and the first reaction process constitutes 20-80% of total polymer giving a polypropylene having a viscosity of 500-1,400 ml/g. PCOPYRIGHT: (C)2008,JPO&INPIT