ymer, propylene-ethylene random copolymer, propylene-ethylene-butylene block copolymer, propylene-ethylene-butylene random copolymer, and ultrahigh molecular weight polypropylene. [0057] Copolymers of propylene with ??-olefin having from 4 to 12 carbon atoms, various vinyl compounds such as styrene, vinyl acetate, (meth)acrylic acid, (meth)acrylic ester, etc. and maleic acid. [0058] (3) ??-Olefin