摘要:
A polymeric insulating material having a high dielectric breakdown voltage 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 µm and greater in diameter and having an average particle size not greater than 1 µm, an organopolysilane, a maleic-anhydride-grafted polypropylene, or a silane compound containing at least one organic polyether group can be added to the polypropylene.
摘要:
A method for molding a polypropylene or a propylene copolymer having a syndiotactic structure which comprises the steps of melting, molding, if desired, quenching and then stretching a propylene homopolymer or a copolymer of propylene and a small amount of ethylene or another α-olefin which has a substantially syndiotactic structure, or a mixture of the same and a small amount of a polypropylene having a substantially isotactic structure. The molded and stretched article can be heated at a temperature of a molding temperature or more, while a load is applied to the article. Furthermore, the molded and stretched article, if desired, can be treated with a hydrocarbon vapor, while a load is applied to the article. The molded article obtained by the method of the present invention has a novel crystalline structure.
摘要:
A polymeric insulating material having a high dielectric breakdown voltage 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 µm and greater in diameter and having an average particle size not greater than 1 µm, an organopolysilane, a maleic-anhydride-grafted polypropylene, or a silane compound containing at least one organic polyether group can be added to the polypropylene.
摘要:
A molded article obtained by blow molding a propylene having a substantially syndiotactic structure or a resin composition comprising a polypropylene having a substantially syndiotactic structure and a copolymer of ethylene and propylene, and a multi-layer molded article obtained from this resin composition in which at least one surface of the molded article is a polypropylene layer having the substantially syndiotactic structure.
摘要:
Extrusion-molded high-transparency articles, especially films and sheets and blown films, obtained by the extrusion of a polypropylene substantially having a syndiotactic structure.
摘要:
A stretched film of polypropylene which is excellent in transparency, substantially free of an antiblocking agent and at least uniaxialy stretched and which is characterized in that it has uniformly distributed projections having a height ranging from 0.05 to 0.50 µ and a width ranging from 10 to 100 µ at least on the surface thereof as well as a method for preparing the foregoing stretched film of polypropylene which comprises the steps of forming, into a sheet, polypropylene which comprises a nucleating agent in an amount selected so that the crystallization temperature of polypropylene is increased by 1 to 10°C by the addition thereof and then stretching the sheet at a temperature ranging from 140 to 165 °C are herein disclosed.