Japan Polypropylene Corporation

Yuji Ryosho

Shigeo Mizukami

Yukihito Zanka

Masashi Shimouse

Kouichi Nakayama

Tomohiro Hosoi

Masahiro Nagata

Ken Shimizu

An object of the present invention is to prevent an occurrence of flow-mark molding defects to improve an appearance of molded articles, and as a means for achieving the object, a propylene-based block copolymer is used as an appearance improver, the copolymer comprising 80 to 60% by weight of crystalline propylene polymer portion which has an intrinsic viscosity [&#x3b7;]p of 0.90 dL/g or less and 20 to 40% by weight of propylene/ethylene random copolymer portion which has an ethylene content of 35 to 50% by weight and an intrinsic viscosity [&#x3b7;]c of 7.0 dL/g or higher ([&#x3b7;]c/[&#x3b7;]p being 7.5 to 30), in which the propylene-based block copolymer has a MFR of 10 to 50 g/10 min.

Propylene-based block copolymer

A moldability modifier capable of improving molding processability, and a polypropylene resin composition using the same suitable for automobile exterior parts are provided. The invention relates to a moldability modifier comprising propylene block copolymer (A) containing from 80 to 98 wt % of a propylene homopolymer portion (A1) and from 2 to 20 wt % of a propylene/ethylene random copolymer portion (A2), wherein the MFR of (A1) is 300 g/10 min or more, the ethylene content of (A2) is from 10 to 70 wt %, the [&#x3b7;] of (A2) is 6.5 dl/g or more, and the MFR as a whole is 40 g/10 min or more; and propylene block copolymer (B) containing from 20 to 79 wt % of a propylene polymer portion (B1) and from 21 to 80 wt % of a propylene/ethylene random copolymer portion (B2), wherein the MFR of (B1) is 20 g/10 min or more, the ethylene content of (B2) is from 20 to 70 wt %, the [&#x3b7;] of (B2) is from 2.5 to 9.0 dl/g, and the MFR as a whole is from 0.1 to 50 g/10 min; and a polypropylene resin composition using the same.

Moldability modifier and polypropylene resin composition using the same

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Mie, Japan

Yuji Ryosho