Chisso Corporation

Other

Yoshitaka Sumi

Takanori Nakashima

Shinichi Akitaya

Yoshitaka Morimoto

Chikashi Okayama

Yasuhiro Mochizuki

Yuya Ishimoto

Hitoshi Kuramochi

Osamu Kojima

Shinji Nakata

A propylene resin composition is constructed so as to contain (A) a propylene-&agr;-olefin random copolymer with the content of a propylene unit of 99.1 to 99.9% by weight, and (B) a propylene-&agr;-olefin random copolymer with the content of a propylene unit of 70 to 90% by weight, in the specified proportion, and to have the specified loss tangent (tan &dgr;) and storage elastic modulus (E&prime;), in the temperature dependence of dynamic viscoelasticity. Thereby, the propylene resin composition is provided, suitable as a raw material for shaped article having a well-balanced combination of transparency, stress-whitening resistance; impact resistance at low temperatures, and further heat resistance.

Propylene resin composition

A molded polypropylene having an excellent balance among various material properties including impact resistance, transparency, gloss, molding shrinkage, and whitening resistance. The molding is constituted of a material comprising a resin composition comprising 10 to 60% by weight crystalline polypropylene (matrix) and 90 to 40% by weight propylene/&agr;-olefin copolymer (domains). The copolymer has been dispersed in the crystalline polypropylene to form domains elongated in the direction (MD) in which the resin composition flows during molding. Each domain is connected to one or more other domains at least at one site (connecting chain).

Molded polypropylene

A propylene block copolymer composition is disclosed which comprises (A) a propylene-&agr;-olefin random copolymer with a propylene content of 99.4 to 99.9 mol % and (B) a propylene-&agr;-olefin random copolymer with a propylene content of 35 to 60 mol %, &agr;-olefin contained in the random copolymer (A) being ethylene and/or 1-butene, wherein the intrinsic viscosity (&lsqb;&eegr; &rsqb;) of the propylene-&agr;-olefin random copolymer (B) ranges from 0.5 to 2.0 dl/g, the ratio (&lsqb;&eegr; &rsqb;/&lsqb;&eegr; &rsqb;) of the intrinsic viscosity (&lsqb;&eegr; &rsqb;) of the propylene-&agr;-olefin random copolymer (B) to the intrinsic viscosity (&lsqb;&eegr; &rsqb;) of the propylene-&agr;-olefin random copolymer (A) ranges from 0.3 to 1.2 and the product ((&lsqb;&eegr; &rsqb;/&lsqb;&eegr; &rsqb;)&times;(W /W )) of the intrinsic viscosity ratio (&lsqb;&eegr; &rsqb;/&lsqb;&eegr; &rsqb;) and the weight ratio (W /W ) of both copolymers ranges from 1.0 to 3.0. The propylene block copolymer composition is suitable as a raw material for molded article having excellent see-through property, transparency, stress-whitening resistance, stiffness and heat resistance.

Propylene block copolymer compositions

Polypropylene composition

A propylene polymer blend is disclosed which comprises (A) a propylene-&agr;-olefin random copolymer with a propylene content of 90 to 99% by weight and (B) a propylene-&agr;-olefin random copolymer with a propylene content of 55 to 90% by weight, wherein the intrinsic viscosity (&lsqb;&eegr;,&rsqb;) of the copolymer B ranges from 1.3 to 3.5 dl/g, the ratio (&lsqb;&eegr;,&rsqb;/&lsqb;&eegr;,&rsqb;) of the intrinsic viscosity (&lsqb;&eegr;,&rsqb;) of the copolymer B to the intrinsic viscosity (&lsqb;&eegr;,&rsqb;) of the copolymer A ranges from 0.5 to 1.3 and a product ((&lsqb;&eegr;,&rsqb;/&lsqb;&eegr;,&rsqb;)&times;(W,/W,)) of the intrinsic ratio (&lsqb;&eegr;,&rsqb;/&lsqb;&eegr;,&rsqb;) of both copolymers and the weight ratio (W,/W,) of both copolymers ranges from 1.0 to 4.5. A polypropylene resin composition comprises 99 to 99.9999% by weight of the propylene polymer blend and 1 to 0.0001% by weight of an &agr;-crystal nucleating agent.

Propylene polymer blends, processes of producing the same and polypropylene resin compositions

An unoriented polypropylene-based film or sheet possessing excellent impact resistance at low temperature, transparency, heat resistance at low temperature and excellent tear strength and/or stress whitening resistance. A molding material which comprises a polypropylene-based resin material comprising 40 to 80% by weight of crystalline polypropylene and 60 to 20% by weight of propylene-&agr;-olefin copolymer containing 20 to 80% by weight of propylene polymerization units, the propylene-&agr;-olefin copolymer dispersed as particles in the crystalline polypropylene, is unoriently molded to afford a film-shaped or sheet-shaped molding, wherein the particle diameter have an aspect ratio (L/D) of mean dispersed particle length (L) to mean dispersed particle diameter along the thickness of the molding (D) of 30 or more in a cross section of the molding along the MD direction, and the mean dispersed particle diameter of 0.3 &mgr;m or less.

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Ichihara, Japan

Yoshitaka Sumi