Mitsui Chemicals, Inc.

Mitsui Toatsu Chemicals, Incorporated

Yukio Ishii

Takayuki Yamada

Takeo Inoue

Tadahiro Sunaga

Shigeru Kimura

Tutomu Iwatani

Ryuichi Sugimoto

Tadashi Asanuma

Masahiro Yamashita

Kenji Michiue

Metallocene compound, and process for preparing polyolefin by using it

An olefin polymerization catalyst system comprising an organic transition metal compound and a support, wherein an organic transition metal compound is soluble in an inert organic solvent and a support which is insoluble in the inert organic solvent, and the support comprises an organic high molecular weight compound which contains a specific carbonyl-containing group. The catalyst system can polymerize an olefin in a high activity, provides polymer with high stereoregularity, prevents adhesion or fouling of the polymer generated in the course of polymerization or an organic aluminum oxy compound on the inner wall of the reactor, leads to high bulk density of the polymer and very reduced level of fisheye and/or gel generation on the processed item, can maintain high productivity, can manufacture high quality product, and thus provides extremely high contribution in industry.

Olefin polymerization catalyst system

The invention provides a polymeric insulating material having a high dielectric breakdown voltage. The material comprises polypropylene which has been obtained in a yield of at least 300,000 g/g-Ti based on titanium in a catalyst upon polymerization, contains ash in an amount not greater than 40 ppm by weight when analyzed by completely burning the polypropylene in air, said ash containing titanium in an amount not greater than 1 ppm by weight based on the weight of the polypropylene, and also contains chlorine in an amount not greater than 2 ppm by weight and boiling n-heptane soluble matter in an amount not smaller than 1 wt. % but not greater than 10 wt. %. To further improve the dielectric breakdown voltage an inorganic oxide or hydroxide free of particles of 10 .mu.m and greater in diameter and having an average particle size not greater than 1 .mu.m, an organopolysilane, a maleic-anhydride-grafted polypropylene, or a silane compound containing at least one organic polyether group can be added to the polypropylene.

Polymeric insulating material and formed article making use of the

The invention provides a polymeric insulating material having a high dielectric breakdown voltage. The material comprises polypropylene which has been obtained in a yield of at least 300,000 g/g-Ti based on titanium in a catalyst upon polymerization, contains ash in an amount not greater than 40 ppm by weight when analyzed by completely burning the polypropylene in air, said ash containing titanium in an amount not greater than 1 ppm by weight based on the weight of the polypropylene, and also contains chlorine in an amount not greater than 2 ppm by weight and boiling n-heptane soluble matter in an amount not smaller than 1 wt. % but not greater than 10 wt. %. According to the invention, it is possible to further improve the dielectric breakdown voltage by adding to the polypropylene an inorganic oxide or hydroxide free of particles of 10 .mu.m and greater in diameter and having an average particle size not greater than 1 .mu.m, an organopolysilane, a maleic-anhydride-grafted polypropylene, or a silane compound containing at least one organic polyether group.

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Osaka, Japan

Yukio Ishii