Sumitomo Chemical Company, Limited

Shigeki Kishiro

Kazuki Wakamatsu

Seiichiro Ima

Takanori Kume

Eisuke Shiratani

Kazunori Kanamori

Kenji Ikeda

A propylene-based copolymer is composed of 60 to 90% by weight of Component (A) that is a polymer component whose major structural unit is a structural unit derived from propylene and 10 to 40% by weight of Component (B) that is a propylene-ethylene copolymer component whose content of a structural unit derived from ethylene is 50 to 80% by weight, wherein the sum total of Component (A) and Component (B) is 100% by weight, wherein the ratio of the intrinsic viscosity of Component (B) ([&#x3b7;]B) to the intrinsic viscosity of Component (A) ([&#x3b7;]A)([&#x3b7;]B/[&#x3b7;]A) satisfies a formula: 1.3&#x3c;[&#x3b7;]B/[&#x3b7;]A&#x2266;2.0, and the melt flow rate, measured at a temperature of 230&#xb0; C. and a load of 21.18 N, of the copolymer is not less than 5 g/10 minutes and not more than 30 g/10 minutes.

Propylene-based copolymer and film made of the same

Low temperature heat-sealable polypropylene-based film

A polypropylene resin composition comprising 100 parts by weight of a polypropylene resin (A) having a die swell ratio of less than about 1.70 and about 0.01 to about 45 parts by weight of a polypropylene resin (B) having a die swell ratio of about 1.80 or more. A T die film is also provided, composing polypropylene wherein the film has a molecular weight distribution of about 4.2 or less and a die swell ratio of 1.28 or more. A method of producing a T die film is also provided, comprising the steps of melt-kneading polypropylene by an extruder, extruding the melted product through a die lip, and cool-solidifying the extruded material by a cooling roll to form a film. The film resulting by this method has a molecular weight distribution about of 4.2 or less and a die swell ratio of about 1.28 or more. Further, the present invention provides a laminated molded body comprising a heat molded body composed of a polypropylene resin composition containing 100 parts by weight of polypropylene resin (A), about 0.01 to about 45 parts by weight of a polypropylene resin (B) and a substrate comprising a thermoplastic resin.

Polypropylene resin composition, T die film made of the same and method of producing T die film

A propylene-based copolymer obtained by copolymerizing propylene with ethylene and/or an &agr;-olefins having 4 or more carbon atoms in the presence of a polymerization catalyst in a first step to produce a copolymer having a content of the &agr;-olefins of 1 mol % or more and less than 15 mol % and an ethylene content of 5 mol % or less in amount of 1 to 30% by weight as a copolymer component (A), and subsequently copolymerizing propylene with ethylene and/or an &agr;-olefins having 4 or more carbon atoms in a second step or later steps to produce a copolymer having a content of the &agr;-olefins of 15 to 30 mol % and an ethylene content of 5 mol % or less in amount of 70 to 99% by weight as a copolymer component (B).

Propylene-based copolymer, process for producing the same and film comprising the same

A propylene-ethylene random copolymer prepared by copolymerizing propylene with ethylene in the substantial absence of a liquid medium with a catalyst system comprising: (A) a solid catalyst component containing magnesium, titanium, a halogen and a first electron donor as an essential component, (B) an organoaluminum compound and (C) a second electron donor compound, wherein an ethylene content (E) of the copolymer is from 3.5 to 7.0% by weight, and wherein a content of a xylene-soluble portion at 20.degree. C. (D) of the copolymer satisfies the relationship D.ltoreq.E+2.0 (% by weight). Films of the copolymer have an excellent appearance (little bleed whitening) and an excellent balance between low-temperature heat-sealing property and rigidity.

Propylene-ethylene random copolymer film

A film having a low dependency of film transparency on film-forming conditions and film thickness, and having superior transparency and rigidity without compromising the original properties of polypropylene film. The film is produced from a polypropylene prepared from a propylene polymer having (1) a stereoirregularity index mmrr/mmmm of a part insoluble in xylene at 20.degree. C. within the range of 0.0095 to 0.0200; (2) a melting temperature within the range of 145.degree. to 160.degree. C.; (3) a part soluble in xylene at 20.degree. C. of 3.5% by weight or less, the polypropylene having: (4) a melt flow rate at 230.degree. C. within the range of 5 to 15 g/10 min.; and (5) a swelling ratio within the range of 1.20 to 1.35.

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Ichihara, Japan

Shigeki Kishiro