Abstract: A process for producing an olefin polymer comprising polymerizing an olefin or olefins in the presence of a catalyst system, in which the catalyst system comprises of (A) a hydrocarbon-insoluble solid catalyst component obtained by treating a uniform hydrocarbon solution containing (a) an magnesium compound, e.g., a dialkoxymagnesium, (b) an titanium compound, e.g., a titanium tetraalkoxide, and (c) a polyalkyltitanate represented by formula (I): ##STR1## wherein R.sup.3 's, which may be the same or different, each represent an alkyl group, an aryl group, or a cycloalkyl group; and p represents an integer of from 2 to 20, with a halogenating agent and (B) an organoaluminum compound. The resulting olefin polymer has broad molecular weight distribution, high melt tension, and high melt elasticity and is freed of fish eye by kneading under ordinary conditions.

Abstract: An ethylene homopolymer or copolymer comprising ethylene and not more than 10% by weight of an .alpha.-olefin having from 3 to 20 carbon atoms and a fuel tank obtained therefrom are disclosed, said ethylene homopolymer or copolymer having (1) an intrinsic viscosity [.eta.] of from 2 to 6 dl/g, (2) a density of from 0.945 to 0.970 g/cm.sup.3, (3) an R value of from 2.5 to 4, said R value being defined as a .sigma..sub.2 /.rho..sub.1 ratio, wherein .sigma..sub.1 and .sigma..sub.2 mean stress in elongation with a strain at 2 sec and 4 sec, respectively, under a flow at an elongational strain rate .epsilon. of 0.5 sec.sup.-1, and (4) a relationship between high-velocity impact strength (HRI-IZOD) measured at -30.degree. C. and a melt index under a load of 21.6 kg (HLMI) satisfying formula:HRI-IZOD.gtoreq.-log HLMI+1.

Abstract: A modified 3-methylbutene-1 polymer as prepared by grafting a monomer containing an unsaturated group onto a 3-methylbutene-1 homo- or copolymer, a 3-methylbutene-1 polymer composition comprising a 3-methylbutene-1 polymer and a fibrous material, and a molded article comprising a mold of a 3-methylbutene-1 polymer and a thin metallic layer provided on the mold.

Abstract: A 3-methylbutene-1 polymer composition comprising:(a) from 10 to 85% by weight of a 3-methylbutene-1 homopolymer or a copolymer of 3-methylbutene-1 with other .alpha.-olefin having from 2 to 18 carbon atoms, which has a heat of fusion of at least 7 cal/g as measured by a differential scanning calorimeter;(b) from 10 to 85% by weight of a copolymer of 3-methylbutene-1 with other .alpha.-olefin having from 2 to 18 carbon atoms, which has a heat of fusion of more than 1 cal/g and less than 7 cal/g as measured by a differential scanning calorimeter; and(c) from 3 to 40% by weight of an elastomeric copolymer of 3-methylbutene-1 with other .alpha.-olefin having from 2 to 18 carbon atoms or an elastomeric copolymer of at least two other olefins having from 2 to 18 carbon atoms, which shows no peak in fusion as measured by a differential scanning calorimeter.

Abstract: A 3-methylbutene-1 polymer composition comprising from 10 to 95% by weight of a 3-methylbutene-1 homopolymer, or a copolymer of 3-methylbutene-1 with other .alpha.-olefin having from 2 to 12 carbon atoms, which has a 3-methylbutene-1 content of higher than 90% by weight, and from 5 to 90% by weight of a copolymer of 3-methylbutene-1 with other .alpha.-olefin having from 2 to 12 carbon atoms, which has a 3-methylbutene-1 content of from 40 to 90% by weight, and a process for its production.

Abstract: In a process for polymerizing an olefin in the presence of a catalyst system combining an organoaluminum compound with a hydrocarbon insoluble solid catalytic component prepared by treating a hydrocarbon solution containing a magnesium compound, and a titanium compound with an aluminum halide having the formulaAlR.sub.l.sup.1 X.sub.3-l.sup.1(R.sup.1 represents an alkyl, aryl or cycloalkyl group and X.sup.1 represents a halogen atom, and l is 1.ltoreq.l.ltoreq.2),an improvement characterized in that the magnesium compound is a compound having the formulaMg(OR.sup.2).sub.m X.sub.2-m.sup.2(R.sup.2 represents an alkyl, aryl or cycloalkyl group; X.sup.2 represents a halogen atom; and m is 1 or 2) and the titanium compound is a compound having the formulaTi(OR.sup.3).sub.n X.sub.4-n.sup.3(R.sup.3 represents an alkyl, aryl or cycloalkyl group; X.sup.3 represents a halogen atom; n is 1, 2 or 3).

Abstract: A process for the preparation of polyolefins, polymerizing olefins with use of a solid catalyst separated from a reaction mixture which is obtained by reducing a halogen-containing compound of vanadium with an organic aluminum compound in the presence of an ether and an organic aluminum compound.

Abstract: Polyolefin is prepared by polymerizing an olefin by using a catalyst system combining an auxiliary catalytic component of an organoaluminum compound and a solid catalytic component obtained by reacting a mixture of a vanadium trichloride ether complex and a titanium trichloride ether complex with an aluminum halide and/or a boron halide.

Abstract: A solid catalytic complex for the polymerization of an olefin has the formula:[MgM.sub.1-n ]X.sub.m . xYwherein M represents a transition metal selected from the group consisting of titanium and vanadium; X represents a halogen atom; Y represents an aliphatic ether or a cyclic ether; n is 0.01 - 0.99; 2<m<4; and 1<x<3.