Mitsui Chemicals, Inc.

Prime Polymer Co., Ltd.

Satoshi Hashizume

Takashi Arai

Keita Itakura

Satoshi Tamura

Toshiyuki Ishii

Munehito Funaya

Ryoichi Tsunori

Yuichi Yamamura

Naritoshi Hirota

Rikuo Onishi

Hiroshi Nishikawa

Shuji Matsumura

Akihiro Inukai

Kunihiko Takesue

Masashi Higuchi

Ayako Kadosaka

Yoshio Sasaki

Kouichirou Yamamoto

Rikuo Ohnishi

Propylene polymers and propylene resin compositions containing the polymers are used as molded articles used under stress for a long period such as automotive parts, housing parts, home appliance parts and electric power tool parts. Stress-resistant molded articles of the invention are obtained from these materials. A propylene homopolymer (A) satisfies the following requirements (1) to (3), and a polypropylene resin composition contains the propylene homopolymer (A). (1) The ratio (Mw/Mn) of weight average molecular weight (Mw) to number average molecular weight (Mn) according to GPC is in the range of 1.2 to 3.5. (2) Mn is in the range of 35,000 to 400,000. (3) The content of components soluble in o-dichlorobenzene at 90&#xb0; C. is not more than 4 wt %.

Propylene homopolymer for stress-resistant molded article, composition containing the polymer, and stress-resistant molded articles obtained therefrom

[Object] To provide a polypropylene resin composition for use in the formation of a microporous membrane having excellent heat resistance and low thermal shrinkage ratio. [Solution] A polypropylene resin composition for use in the formation of a microporous membrane according to the present invention comprises as an essential component a propylene homopolymer (A) that satisfies the following requirements (1) to (4) and (7):

Polypropylene resin composition for use in formation of microporous membrane

[Object] To provide a propylene homopolymer suitable for capacitor films having high withstand voltage and a stretched film formed by stretching the propylene homopolymer. [Solution] A propylene homopolymer of the present invention for capacitors satisfies the following requirements (i) to (v) and (ix): (i) the MFR is 1 to 10 g/10 minutes; (ii) the meso pentad fraction (mmmm) measured byC-NMR is 0.940 to 0.995; (iii) the integrted amount of elution at 90&#xb0; C. by CFC using o-dichlorobenzene is 0.5% by weight or less; (iv) the melting point measured using DSC is 152&#xb0; C. or more; (v) the chlorine content is 2 ppm by weight or less; and (ix) in an elution temperature-elution volume curve measured by cross-fractionation chromatography (CFC) using o-dichlorobenzene, the maximum peak has a peak top temperature in the range of 105&#xb0; C. to 130&#xb0; C. and half width of 7.0&#xb0; C. or less.

Propylene homopolymer for capacitors

The present invention relates to a propylene random copolymer which satisfies the following requirements [1] to [4], and to various useful molded products obtained by molding the propylene random copolymer:

Propylene polymer particle method of producing the same and use thereof

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Takaishi, Japan

Satoshi Hashizume