The present disclosure provides methods for producing an olefin polymer by contacting a C.sub.3-C.sub.40 olefin, ethylene and a diene with a catalyst system including an activator and a metallocene catalyst compound comprising a substituted or unsubstituted indacenyl group and obtaining a C.sub.3-C.sub.40 olefin-ethylene-diene terpolymer typically comprising from 30 to 55 mol % ethylene, from 69.09 to 45 mol % C.sub.3 to C.sub.40 comonomer, and from 0.01 to 7 mol % diene wherein the Tg of the terpolymer is −28° C. or less. Preferably, a propylene-ethylene-ethylidene norbornene is obtained.

The present disclosure provides methods for producing an olefin polymer by contacting a C.sub.3-C.sub.40 olefin, ethylene and a diene with a catalyst system including an activator and a metallocene catalyst compound comprising a substituted or unsubstituted indacenyl group and obtaining a C.sub.3-C.sub.40 olefin-ethylene-diene terpolymer typically comprising from 30 to 55 mol % ethylene, from 69.09 to 45 mol % C.sub.3 to C.sub.40 comonomer, and from 0.01 to 7 mol % diene wherein the Tg of the terpolymer is −28° C. or less. Preferably, a propylene-ethylene-ethylidene norbornene is obtained.

The ultrahigh-molecular-weight polyethylene powder of the present invention is an ultrahigh-molecular-weight polyethylene powder having a viscosity-average molecular weight Mv of 10×10.sup.4 or higher and 1000×10.sup.4 or lower, wherein viscosity-average molecular weight Mv(A) of a kneaded product obtained by kneading under specific kneading conditions, and the Mv satisfy the following relationship: “{Mv−Mv(A)}/Mv is 0.20 or less”, and the ultrahigh-molecular-weight polyethylene powder contains an ultrahigh-molecular-weight polyethylene powder having a particle size of 212 μm or larger, wherein the powder having a particle size of 212 μm or larger has an average pore volume of 0.6 ml/g or larger and an average pore size of 0.3 μm or larger.

The present invention provides a process for the preparation of a multimodal polyethylene comprising: (i) polymerising ethylene and optionally an α-olefin comonomer in a first polymerisation stage to produce a first ethylene polymer; and (ii) polymerising ethylene and optionally an α-olefin comonomer, in the presence of said first ethylene polymer, in a second polymerisation stage, wherein the first and second polymerisation stages are carried out in the presence of an unsupported metallocene catalyst and each polymerisation stage produces at least 5% wt of the multimodal polyethylene, and the multimodal polyethylene has a multimodal molecular weight distribution, a molecular weight of at least 50,000 g/mol and a bulk density of at least 250 g/dm.sup.3, and wherein a solution of the unsupported metallocene catalyst in a solvent is employed. The present invention also provides a multimodal polyethylene, a process for preparing a pipe comprising preparing a multimodal polyethylene and extruding the multimodal recycle polyethylene to produce a pipe, and a pipe obtained by such a process.

The present invention provides a process for the preparation of a multimodal polyethylene comprising: (i) polymerising ethylene and optionally an α-olefin comonomer in a first polymerisation stage to produce a first ethylene polymer; and (ii) polymerising ethylene and optionally an α-olefin comonomer, in the presence of said first ethylene polymer, in a second polymerisation stage, wherein the first and second polymerisation stages are carried out in the presence of an unsupported metallocene catalyst and each polymerisation stage produces at least 5% wt of the multimodal polyethylene, and the multimodal polyethylene has a multimodal molecular weight distribution, a molecular weight of at least 50,000 g/mol and a bulk density of at least 250 g/dm.sup.3, and wherein a solution of the unsupported metallocene catalyst in a solvent is employed. The present invention also provides a multimodal polyethylene, a process for preparing a pipe comprising preparing a multimodal polyethylene and extruding the multimodal recycle polyethylene to produce a pipe, and a pipe obtained by such a process.

A method for producing an olefin polymerization catalyst includes bringing a solid catalyst component for olefin polymerization, a vinylsilane compound, an organosilicon compound, and an organoaluminum compound into contact with each other in an inert organic solvent under an inert gas atmosphere in the absence of a specific vinyl compound, wherein a washing treatment is not performed after the vinylsilane compound has been added to the reaction system, the solid catalyst component includes a magnesium compound, a titanium halide compound, and an electron donor compound that does not include a phthalic acid ester structure, and includes a diol skeleton, and the organosilicon compound does not include a vinyl group, and includes at least one group selected from an alkoxy group and an amino group.

A method for producing an olefin polymerization catalyst includes bringing a solid catalyst component for olefin polymerization, a vinylsilane compound, an organosilicon compound, and an organoaluminum compound into contact with each other in an inert organic solvent under an inert gas atmosphere in the absence of a specific vinyl compound, wherein a washing treatment is not performed after the vinylsilane compound has been added to the reaction system, the solid catalyst component includes a magnesium compound, a titanium halide compound, and an electron donor compound that does not include a phthalic acid ester structure, and includes a diol skeleton, and the organosilicon compound does not include a vinyl group, and includes at least one group selected from an alkoxy group and an amino group.

The present invention relates to a cable jacket composition comprising a multimodal olefin copolymer, said copolymer having density of 0.935-0.960 g/cm.sup.3 and MFR.sub.2 of 2.2-10.0 g/10 min and said composition having ESCR of at least 2000 hours and a cable shrinkage of 0.70% or lower. The invention further relates to the process for preparing said composition and its use as outer jacket layer for a cable, preferably a communication cable, most preferably a fiber optic cable.

The present invention relates to a cable jacket composition comprising a multimodal olefin copolymer, said copolymer having density of 0.935-0.960 g/cm.sup.3 and MFR.sub.2 of 2.2-10.0 g/10 min and said composition having ESCR of at least 2000 hours and a cable shrinkage of 0.70% or lower. The invention further relates to the process for preparing said composition and its use as outer jacket layer for a cable, preferably a communication cable, most preferably a fiber optic cable.

The present disclosure relates to olefin polymerization catalysts, and discloses a catalyst component for olefin polymerization or copolymerization and a preparation method therefor, and a catalyst and an application thereof. The catalyst component for olefin polymerization or copolymerization in the present disclosure comprises titanium element, magnesium element, an electron donor, an organic silicon polymer, and an inorganic oxide support, wherein the molecular composition of the organic silicon polymer is [R.sub.xSiO.sub.(4-x)/2].sub.m, wherein R is selected from alkyl, aryl, vinyl or oxygen, x is 0 or more and 2 or less, and the value of m makes the number-average molecular weight of the organic silicon polymer be 1×10.sup.3-1×10.sup.6 g/mol. The catalyst has the characteristics of high activity, good hydrogen-regulating copolymerization performance, high bulk density of resulting polymer powder, and a low content of fine powder in the polymer powder when applied to olefin polymerization, particularly to ethylene and α-olefin polymerization.