PP/UHMW-PE (Polypropylene-Ultrahigh-Molecular-Weight-Polyethylene) composition having: —a melting temperature Tm in the range of 125 to 150° C. (DSC, ISO 11357, Part 3), —an MFR2 of 0.15 to 0.60 g/10min (2.16 kg, 230° C., IS01133), —units derived from 1-hexene in an amount of at least 1.80 wt.-%, and—a XS according to IS116152 of less than 5.0 wt.-% all weight percentages with respect to the total PP/UHMW-PE composition.

A composite sliding block to be arranged between two supporting plates of a frictional-type seismic isolator, with one supporting plate connected to the superstructure to be isolated and the other to the foundations, comprising two contact components that externally are slidingly or articulatedly in contact with said supporting plates, depending on whether the isolator has one or two sliding surfaces, and internally are coupled to each other by means of a male projection of one component in a female recess of the other. An elastomeric seal occupies an empty space surrounding the projection within the recess and, on the external side of the contact component(s) slidingly in contact with the supporting plate(s), a sliding plate is accommodated in a corresponding niche having an elastomeric compression support at the bottom. Frictional pendulum-type isolators with one or two concave sliding surfaces include such a block.

A method comprising introducing a polymerization feed comprising an α-olefin, a diluent, and a diene to a polymerization system, under polymerization conditions, whereby a polymer product is produced, wherein the diene is present at a level in the range of from about 1 ppm to about 1000 ppm based on the diluent.

A polyolefin porous separator includes a first surface and a second surface corresponding to the first surface. The surfaces of the polyolefin porous separator contain dendritic crystals and micropores, the dendritic crystals intersect with the micropores on the first surface or/and the second surface, and the dendritic crystals penetrate through the second surface from the first surface. A preparation method of the polyolefin porous separator includes: (1) a mixed melting of polyethylene resin and a mineral oil; (2) an extrusion of the mineral oil/polyethylene resin molten mixture; (3) a stretching of a thick sheet in a machine direction (MD); (4) a stretching of the separator in a transverse direction (TD); (5) immersing the separator into a solvent to extract the mineral oil; (6) a secondary stretching of the separator in the TD; and (7) subjecting the separator having the longitudinal crystals to a heat-setting treatment and then rolling up.

An object of the present invention is to obtain an ethylene-based polymer composition useful as a material for shaped articles having a low surface resistivity and a low volume resistivity and exhibiting excellent slidability. The present invention pertains to an ethylene-based polymer composition containing an ethylene-based polymer (A) and a carbon-based filler (C), the ethylene-based polymer composition having a melt flow rate (MFR) in the range of 0.1 to 20 g/10 min as measured in accordance with JIS K7210-1: 2014 at a measurement temperature of 230° C. under a load of 10 kgf.

The present disclosure relates to a polyethylene having high degree of crosslinking and a crosslinked polyethylene pipe including the same. The polyethylene according to the present disclosure has a high content of ultra-high molecular weight, and thus a crosslinking rate is improved, and thus a sufficient degree of crosslinking is exhibited even when the crosslinking time is shortened, thereby exhibiting excellent strength and pressure resistance characteristics.

A process for the preparation of an ultra-high molecular weight ethylene homopolymer having a MFR.sub.21 of 0.01 g/10 min or less, said process comprising: (I) prepolymerising at least ethylene at a temperature of 0 to 90° C. in the presence of a heterogeneous Ziegler Natta catalyst to prepare an ethylene prepolymer having an Mw of 40,000 to 600,000 g/mol; and thereafter in the presence of the prepolymer and said catalyst; (II) polymerising ethylene at a temperature of 55° C. or less, such as 20 to 55° C., to prepare said UHMW ethylene homopolymer; wherein the UHMW ethylene homopolymer comprises up to 8 wt. % of said prepolymer.

A process for the preparation of an ultra-high molecular weight ethylene homopolymer having a MFR.sub.21 of 0.01 g/10 min or less, said process comprising: (I) prepolymerising at least ethylene at a temperature of 0 to 90° C. in the presence of a heterogeneous Ziegler Natta catalyst to prepare an ethylene prepolymer having an Mw of 40,000 to 600,000 g/mol; and thereafter in the presence of the prepolymer and said catalyst; (II) polymerising ethylene at a temperature of 55° C. or less, such as 20 to 55° C., to prepare said UHMW ethylene homopolymer; wherein the UHMW ethylene homopolymer comprises up to 8 wt.% of said prepolymer.

A polymer composition for producing gel extruded articles is described. The polymer composition contains polyethylene particles combined with a plasticizer. The polyethylene particles are particularly selected so that the particles rapidly form a homogeneous gel-like material when combined with the plasticizer during gel processing. In one embodiment, the polyethylene used to produce the particles has a relatively low bulk density. Alternatively or in addition, the particles can have a carefully controlled particle size distribution. Polymer articles such as fibers and films can be produced having little to no imperfections.

The polyethylene powder satisfies (requirements 1 and 2). (Requirement 1): an intrinsic viscosity (IV) is 1.5 dL/g or more and 34.0 dL/g or less, and (requirement 2): a ratio γ.sub.0/γ.sub.1 of an elastic limit strain γ.sub.0 at a swelling time t (h) of 0 hours to an elastic limit strain γ.sub.1 at a swelling time t (h) of 1 hour is 0.80 or more and 0.95 or less, wherein the ratio is obtained from a strain dependence test .