Mitsui Chemicals, Inc.

Grand Polymer Co., Ltd.

Tadashi Imai

Keiji Okada

Akira Uchiyama

Mikio Hashimoto

Yoshiyuki Ogawa

Masakazu Jitsukata

Ryohei Shiga

Akihide Mori

Takuo Asami

Shigeru Harima

Shigeyuki Yasui

Takashi Yamasaki

Yasuhiro Isaji

Disclosed is a thermoplastic elastomer composition containing 10-60 parts by weight of a non-crosslinkable crystalline polyolefin resin (A), 1-30 parts by weight of a specific propylene 1-butene random copolymer (B) and 89-10 parts by weight of an ethylene &#x3b1;-olefin non-conjugated polyene copolymer rubber (C) which is composed of ethylene, an &#x3b1;-olefin having 3-20 carbon atoms and a non-conjugated polyene, in such amounts that the total of the components (A), (B) and (C) is 100 parts by weight. The thermoplastic elastomer composition is dynamically crosslinked by an extruder. This thermoplastic elastomer is excellent in moldability and economic efficiency, and enables to obtain a molded body exhibiting sufficient adhesion strength to a vulcanized rubber or thermoplastic elastomer without the intermediation of an adhesive layer, as well as a lightweight molded body having sufficient hardness and rubber elasticity.

Thermoplastic elastomer composition

A thermoplastic elastomer excellent in rubber elasticity and extrudability and a molded object thereof. The thermoplastic elastomer comprises a partly or wholly crosslinked rubber (A), an isotactic polypropylene (B) having an isotactic pentad content of 0.8 or higher, a syndiotactic polypropylene (C) having a syndiotactic pentad content of 0.6 or higher, and a softener (D), the content of the syndiotactic of the syndiotactic polypropylene (C) being in the range of 0.5 to 10 wt. % based on the sum of the crosslinked rubber (A), isotactic polypropylene (B), syndiotactic polypropylene (C), and softener (D), the thermoplastic elastomer having a melt flow rate of 0.01 to 1000 g/10 min as measured in accordance with ASTMD 1238 at 230&#xb0; C. under a load of 10 kg. The molded object is obtained by extrusion-molding the elastomer.

Thermoplastic elastomer and molded article thereof

The olefin thermoplastic elastomer of the invention has an islands-sea structure, in which the average particle diameter of the islands phases is not more than 2 &mgr;m, and has a gel fraction ranging from 0.5 to 15% by weight and a quantity of heat of melt at a temperature of 125&deg; C. or below, as measured in a different scanning calorimeter (DSC), of 40% or more of the total quantity of heat of melt. The olefin thermoplastic elastomer can be obtained by melt blending in the presence of a crosslinking agent of a specific amount a blend that contains specific amounts of: a high density polyethylene having a density of 0.940 g/cm or more, or a crystalline ethylene polymer having a crystallinity determined by a DSC method of 10% or more and a density of less than 0.940 g/cm , an ethylene/&agr;-olefin(/non-conjugated polyene) copolymer rubber comprising ethylene, an &agr;-olefin of 3 to 20 carbon atoms and optionally a non-conjugated polyene, and a polypropylene.

Olefin thermoplastic elastomer, process for producing the same and use thereof

Polypropylene resin composition and injection-molded article thereof

Growing community of inventors

Ichihara, Japan

Tadashi Imai