Abstract: Ultra-high-molecular-weight polyolefin fine powder characterized in that said fine powder has an intrinsic viscosity measured in decalin at 135.degree. C. of at least 10 dl/g and an average particle diameter in the range of 1-80 .mu.m, at least 20 weight % of the powder passing through 350 Tyler mesh screen.

Abstract: A polyethylene composition having excellent melt moldability which substantially comprises an ultrahigh-molecular-weight polyethylene having a molecular weight of, for example, at least about 1,650,000 and a low-molecular-weight to high-molecular-weight polyethylene having a molecular weight of, for example, about 1500 to about 360,000. The composition is produced by a multi-stage polymerization process involving a step of producing the ultrahigh-molecular-weight polyethylene and a step of producing the low-molecular-weight to high-molecular-weight polyethylene.

Abstract: A thermoplastic resin composition comprising a melt mixed product of (A) 70% to 98% by weight of at least one thermoplastic resin selected from the group consisting of polyamides, polyacetals, polyesters, and polycarbonates and (B) 30% to 2% by weight of ultra-high molecular weight polyolefin powder having an intrinsic viscosity [.eta.] of 10 dl/g or more, measured in decalin at 135.degree. C., and having an average particle size of 80 .mu.m or less and having a particle size distribution such that substantially all of the powder particles pass through a sieve having a sieve number of 100 and at least 20% by weight of the total powder particles pass through a sieve having a sieve number of 350.This thermoplastic resin composition has excellent abrasion resistance, excellent impact resistance, and a high critical PV value.

Abstract: A process for producing a random terpolymer of ethylene and alpha-olefins having at least 3 carbon atoms in the presence of a catalyst composed of (1) a titanium catalyst component containing at least magnesium and titanium and (2) an organoaluminum catalyst component in a hydrocarbon solvent at a temperature above the melting point of the terpolymer formed, under such conditions that the resulting copolymer dissolves in the hydrocarbon solvent; characterized in that said terpolymer consists essentially of(A) more than 90 mole % to 99.5 mole % of ethylene,(B) 0.2 mole % to 9.8 mole % of an alpha-olefin with 3 to 4 carbon atoms, and(C) 0.2 mole % to 9.8 mole % of an alpha-olefin with 5 to 18 carbon atoms,the total of the proportions of the monomers (A), (B) and (C) being 100 mole %.