New Japan Chemical Co., Ltd.

Naoki Ikeda

Kiyoshi Sadamitsu

Masafumi Yoshimura

Manabu Hoki

Kenichiro Nagata

Kazuaki Mizoguchi

Hiroshi Kitagawa

Koichi Ogino

Toshiaki Kobayashi

Yoshiharu Kimura

Yasuyuki Kawahara

Yuji Kawashima

Disclosed is a successively biaxially stretched film obtained by successive biaxial stretching method comprising extruding a melt of a &#x3b2;-crystal nucleating agent-containing polypropylene-based resin composition from a T-die, cooling the extruded resin on a chill roll, and stretching the resulting web sheet longitudinally and then transversely, wherein the longitudinally stretched sheet is made to have a degree of &#x3b2;-crystal orientation of less than 0.3 by the following method (I) and/or (II), optionally subjected to annealing treatment, and transversely stretched: method (I): melting the polypropylene-based resin composition containing needle crystals of a specific &#x3b2;-crystal nucleating agent at a temperature not lower than m.p. of the polypropylene-based resin and lower than dissolution temperature of the &#x3b2;-crystal nucleating agent in the polypropylene-based resin melt, and extruding the melt from the T-die at the same temperature, method (II): adjusting neck-in ratio during longitudinal stretching to 25 to 55%. The porous polypropylene film has good breakage resistance during manufacture, excellent thickness uniformity, high porosity and air-permeability, and is useful for battery separators.

Successively biaxial-oriented porous polypropylene film and process for production thereof

Disclosed is a successively biaxially stretched film obtained by successive biaxial stretching method comprising extruding a melt of a &#x3b2;-crystal nucleating agent-containing polypropylene-based resin composition from a T-die, cooling the extruded resin on a chill roll, and stretching the resulting web sheet longitudinally and then transversely, wherein the longitudinally stretched sheet is made to have a degree of &#x3b2;-crystal orientation of less than 0.3 by the following method (I) and/or (II), optionally subjected to annealing treatment, and transversely stretched: The porous polypropylene film has good breakage resistance during manufacture, excellent thickness uniformity, high porosity and air-permeability, and is useful for battery separators.

Disclosed is a porous film made of a resin composition containing (I) (i) a propylene-ethylene copolymer or (ii) a polypropylene-based resin mixture containing a propylene-ethylene copolymer, each having an ethylene content of 3.0 to 7.0 wt. % and an MFR measured at 230&#xb0; C. of 2.0 to 4.0 g/10 min and (II) a &#x3b2;-crystal nucleating agent; the film having a porosity of 20 to 80%, a Gurley air permeability of 5,000 sec/100 cc or lower as measured according to JIS P-8117, a water vapor permeability of 2,000 g/m&#xb7;24 h or higher as measured according to JIS Z-0208 and a water pressure resistance of 75 kPa or higher as measured according to JIS L-1092 using an aqueous surfactant solution; a process for producing the same; and an absorbent article employing the porous film as a backsheet.

Porous polypropylene film, process for producing the same, and absorbent article employing the film

Disclosed are a crystalline polypropylene resin composition comprising a crystalline polyproplylene resin and a &bgr;-nucleating agent, and a method of increasing the proportion of &bgr;-form crystals in a crystalline polypropylene resin molding comprising molding the composition, the &bgr;-nucleating agent being a diamide compound.

Crystalline polypropylene resin composition and amide compounds

Disclosed are a polybutene-1 resin composition comprising a polybutene-1 resin and a Form-II to Form-I crystal transformation accelerator, and a method of accelerating the Form-II to Form-I crystal transformation comprising molding the polybutene-1 resin composition and allowing the molded product to stand at about 0 to 50.degree. C., the crystal transformation accelerator being an amide compound.

Polybutene-1 resin composition and a method of accelerating the crystal

Disclosed are a process for producing a porous stretched article of .beta.-crystalline polypropylene-based resin, the process comprising the steps of crystallizing a melt of a polypropylene-based resin composition at a temperature of 15.degree. to 140.degree. C. to form a solidified product containing .beta.-form crystals and stretching the resulting solidified product at a temprature which is higher than 20.degree. C. but lower than the melting point of the .beta.-form crystals in said solidified product, the polypropylene-based resin composition comprising a polypropylene-based resin and 0.0001 to 5 parts by weight, per 100 parts by weight of the polypropylene-based resin, of at least one specific amide compound; and a porous stretched article produced by the process.

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Kyoto, Japan

Naoki Ikeda