Abstract: To provide an ultrahigh molecular weight polyethylene stretched microporous film having high strength and heat resistance. An ultrahigh molecular weight polyethylene stretched microporous film, which comprises at least an ultrahigh molecular weight polyethylene having an intrinsic viscosity ([?]) of at least 7 dl/g and at most 60 dl/g, and which has a porosity of at least 10% and at most 70% and a breaking stress of at least 1 MPa when melt-stretched at 150° C., which uses, as the ultrahigh molecular weight polyethylene, preferably ultrahigh molecular weight polyethylene particles which satisfy (1) an intrinsic viscosity ([?]) of at least 7 dl/g and at most 60 dl/g, (2) a bulk density of at least 130 kg/m3 and at most 700 kg/m3, and (3) ?Tm (?Tm=Tm1?Tm2) of at least 9° C. and at most 30° C., which is a difference between the melting point (Tm1) at the 1st scanning and the melting point (Tm2) at the 2nd scanning measured by DSC.

Abstract: To provide novel ultrahigh molecular weight polyethylene particles having a high melting point and exhibiting high crystallinity, thus capable of providing a molded product excellent in mechanical strength, thermal resistance and abrasion resistance. Ultrahigh molecular weight polyethylene particles which satisfy that (1) the intrinsic viscosity (?) is at least 15 dL/g and at most 60 dL/g, (2) the bulk density is at least 130 kg/m3 and at most 700 kg/m3, and (3) ?Tm (?Tm=Tm1?Tm2) i.e. the difference between a melting point (Tm1) in 1st scan and a melting point (Tm2) in 2nd scan, measured by a differential scanning calorimeter (DSC), is at least 11° C. and at most 30° C.

Abstract: To provide an ultrahigh molecular weight polyethylene stretched microporous film having high strength and heat resistance. An ultrahigh molecular weight polyethylene stretched microporous film, which comprises at least an ultrahigh molecular weight polyethylene having an intrinsic viscosity ([?]) of at least 7 dl/g and at most 60 dl/g, and which has a porosity of at least 10% and at most 70% and a breaking stress of at least 1 MPa when melt-stretched at 150° C., which uses, as the ultrahigh molecular weight polyethylene, preferably ultrahigh molecular weight polyethylene particles which satisfy (1) an intrinsic viscosity ([?]) of at least 7 dl/g and at most 60 dl/g, (2) a bulk density of at least 130 kg/m3 and at most 700 kg/m3, and (3) ?Tm (?Tm=Tm1?Tm2) of at least 9° C. and at most 30° C., which is a difference between the melting point (Tm1) at the 1st scanning and the melting point (Tm2) at the 2nd scanning measured by DSC.

Abstract: To provide novel ultrahigh molecular weight polyethylene particles having a high melting point and exhibiting high crystallinity, thus capable of providing a molded product excellent in mechanical strength, thermal resistance and abrasion resistance. Ultrahigh molecular weight polyethylene particles which satisfy that (1) the intrinsic viscosity (?) is at least 15 dL/g and at most 60 dL/g, (2) the bulk density is at least 130 kg/m3 and at most 700 kg/m3, and (3) ?Tm (?Tm=Tm1?Tm2) i.e. the difference between a melting point (Tm1) in 1st scan and a melting point (Tm2) in 2nd scan, measured by a differential scanning calorimeter (DSC), is at least 11° C. and at most 30° C.

Abstract: An object of the present invention relates to provide an ethylene polymer having excellent mechanical strength and excellent molding processability in a wide molding processing temperature range. The invention relates to use an ethylene polymer comprising a repeating unit derived from ethylene, or a repeating unit derived from ethylene and a repeating unit derived from a C3-8 ?-olefin, the ethylene polymer being satisfied with the following (A) to (F). (A) Density (d (kg/m3)) is from 910 to 970, (B) MFR (g/10 min)) is from 0.01 to 50, (C) terminal vinyl number is 0.2 or less per 1,000 carbon atoms, (D) melt strength (MS160 (mN)) measured at 160° C. and MFR are satisfied with MS160>90?130×log(MFR), (E) melt strength (MS190 (mN)) measured at 190° C. and MS160 are satisfied with MS160/MS190<1.8, and (F) fluidized activation energy (Ea (kJ/mol)) and d are satisfied with 127?0.107d<Ea<88?0.060d.

Abstract: A polyethylene composition prepared by polymerizing ethylene and an optional olefin with ?3 carbon atoms in the presence of a macromonomer, is provided. The macromonomer is a vinyl-terminated ethylene polymer prepared by polymerizing ethylene and an optional olefin with ?3 carbon atoms, and the macromonomer has (A) Mn?5,000, and Mw/Mn=2-5. The polyethylene composition comprises (C) branched polyethylene prepared by copolymerizing ethylene, the macromonomer and an optional olefin with ?3 carbon atoms, and the macromonomer. The polyethylene composition has (D) a density of 0.890-0.980 g/cm3, (E) Mw=30,000-10,000,000, (F) Mw/Mn=2-30, (G) a long chain branch frequency of 0.01-3 per 1,000 C atoms, and (H) a shrinking factor (g? value) of 0.1-0.9 as measured by GPC/intrinsic-viscosity. The polyethylene composition can be finely divided particles having (P) a powder bulk density of 0.15-0.50 g/cm3.

Abstract: A polyethylene composition prepared by polymerizing ethylene and an optional olefin with ≧3 carbon atoms in the presence of a macromonomer, is provided. The macromonomer is a vinyl-terminated ethylene polymer prepared by polymerizing ethylene and an optional olefin with ≧3 carbon atoms, and the macromonomer has (A) Mn≧5,000, and Mw/Mn=2-5. The polyethylene composition comprises (C) branched polyethylene prepared by copolymerizing ethylene, the macromonomer and an optional olefin with ≧3 carbon atoms, and the macromonomer. The polyethylene composition has (D) a density of 0.890-0.980 g/cm3, (E) Mw=30,000-10,000,000, (F) Mw/Mn=2-30, (G) a long chain branch frequency of 0.01-3 per 1,000 C atoms, and (H) a shrinking factor (g′ value) of 0.1-0.9 as measured by GPC/intrinsic-viscosity. The polyethylene composition can be finely divided particles having (P) a powder bulk density of 0.15-0.50 g/cm3.