Sumitomo Chemical Company, Limited

Other

Toyota Jidosha Kabushiki Kaisha

Teruhiko Doi

Kenichi Ohkawa

Takeyoshi Nishio

Yuichi Miyake

Takao Nomura

Manabu Hirakawa

Hajime Sadatoshi

Tetsuya Hisayama

Akihiro Morimoto

Thermoplastic resin composition and injection molded article thereof

A high rigidity ethylene-propylene block copolymer which is composed of (I) a crystalline polypropylene portion and (II) an ethylene-propylene random copolymer portion, and in which the crystalline polypropylene portion (I) has a Q value of not more than 5 which is the weight average molecular weight (Mw)/number average molecular weight (Mn) ratio obtained by a gel permeation chromatography (GPC) method, an isotactic pentad fraction of not less than 0.98 as calculated from,C-NMR, and an intrinsic viscosity of 0.6 to 0.88 dl/g as measured at 135&deg; C. in tetralin; the ethylene-propylene random copolymer portion (II) has an intrinsic viscosity of 4.0 to 6.0 dl/g as measured at 135&deg; C. in tetralin and an ethylene/propylene ratio of 25/75 to 35/65 by weight; and when the total of the above polymers ((I)&plus;(II)) is taken as 100% by weight, the content of the ethylene-propylene random copolymer portion (II) is 8 to 22% by weight, and a process for producing the same.

High-rigidity ethylene/propylene block copolymer and process for the production thereof

A polypropylene-based resin composition comprising:

Polypropylene-based resin composition

A thermoplastic resin composition which has a melt flow rate of 25 to 30 g/10 min and a flexural modulus at 23.degree. C. of 20,000 kg/cm.sup.2 or more and which comprises (1) 78 to 87% by weight of a specific crystalline polypropylene �referred to hereinafter as (A)! in which the propylene homopolymer portion has a Q value of 3.0 to 5.0, an isotactic pentad fraction of 0.975 or more and an intrinsic viscosity �.eta.! of 1.00 to 1.10 dl/g as measured at 135.degree. C. in tetralin, (2) 3 to 10% by weight of at least two specific rubber components selected from the group consisting of (B) 1 to 9% by weight of an ethylene-butene-1 copolymer rubber, (C) 1 to 9% by weight of an ethylene-propylene copolymer rubber and (D) 1 to 9% by weight of an alkenyl aromatic compound-containing rubber; and (3) 10 to 12% by weight of talc having an average particle diameter of 4 .mu.m or less, and an injection molded article of the thermoplastic resin composition, said thermoplastic resin composition satisfying the impact strength and rigidity required as a material for an interior automotive trim and having a short molding cycle and good surface quality.

Crystalline ethylene-propylene copolymer with ethylene copolymer(s)

A thermoplastic resin composition which has a melt flow rate of 20 to 30 g/10 min and a flexural modulus at 23.degree. C. of 30,000 kg/cm.sup.2 or more and which comprises (A) 60 to 75% by weight of a specific crystalline polypropylene in which the propylene homopolymer portion has a Q value of 3.0 to 5.0, an isotactic pentad fraction of 0.975 or more and an intrinsic viscosity �.eta.! of 0.95 to 1.15 dl/g as measured at 135.degree. C. in tetralin, (B) 2 to 8% by weight of an ethylene-butene-1 copolymer rubber, (C) 2 to 8% by weight of an ethylene-propylene copolymer rubber, (D) 10 to 20% by weight of talc having an average particle diameter of 4 .mu.m or less, and (E) 5 to 20% by weight of fibrous magnesium oxysulfate, and an injection molded article of the thermoplastic resin composition, said thermoplastic resin composition satisfying the impact strength and rigidity required as a material for an instrumental panel and having a short molding cycle and good surface quality.

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Sodegaura, Japan

Teruhiko Doi