Mitsui Chemicals, Inc.

Nobuhisa Mikawa

Norio Kashiwa

Keiji Okada

Tomoaki Matsugi

Shinichi Kojoh

Kenji Sugimura

Munehito Funaya

Nobuo Kawahara

Toshiyuki Hirose

Shingo Matsuo

Kouichi Kizu

Motoyasu Yasui

Hideyuki Kaneko

Tooru Tanaka

Naritoshi Hirota

Yasuhiro Kai

Kazuto Sugiyama

Akiyoshi Taguchi

There are provided a polyolefin resin composition having excellent mechanical properties and thermal resistance; a film formed of the polyolefin resin composition, which has excellent mechanical properties and thermal resistance and which is less likely to suffer from fisheyes; a microporous membrane having excellent permeability and shutdown properties in addition to the above-mentioned physical properties; and applications thereof. Such objects are accomplished by a polyolefin resin composition containing an ultra-high molecular weight ethylene polymer (A), a 4-methyl-1-pentene polymer or 3-methyl-1-pentene polymer (B), and a polymer of an olefin having 2 to 12 carbon atoms (C) at an intended ratio.

Polyolefin resin composition and applications thereof

A novel olefin-based polymer has excellent thermal resistance, as well as excellent balance among various properties. The olefin-based polymer is an olefin-based polymer comprising 50 to 100% by weight of a constituent unit derived from 4-methyl-1-pentene, and 0 to 50% by weight of a constituent unit derived from at least one olefin selected from olefins having 2 to 20 carbon atoms except 4-methyl-1-pentene, and having the following properties: i) the diad isotacticity is 70% or greater, ii) the ratio (Mw/Mn) of the weight average molecular weight (Mw) to the number average molecular weight (Mn) as measured by gel permeation chromatography (GPC) is in the range of 1.0 to 3.5, and iii) the intrinsic viscosity [&#x3b7;] is 0.5 (dl/g) or greater.

Olefin-based polymers and uses thereof

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Chiba, Japan

Nobuhisa Mikawa