Abstract: An electrical insulating material for use in electrical insulators, for example, for insulated electric wires such as internal wiring of electronic equipment, automobiles or the like, electrical insulating covers produced from the electrical insulating material and a method of electrical insulation using the material are provided. More particularly, it relates to an electrical insulating material which is excellent in mechanical properties and durability, an electrical insulating cover produced from the material and a method of electrical insulation using the material.

Abstract: An electrical insulating material for use in electrical insulators, for example, for insulated electric wires such as internal wiring of electronic equipment, automobiles or the like, electrical insulating covers produced from the electrical insulating material and a method of electrical insulation using the material are provided. More particularly, it relates to an electrical insulating material which is excellent in mechanical properties and durability, an electrical insulating cover produced from the material and a method of electrical insulation using the material.

Abstract: A method for producing an .alpha.-olefin block copolymer, which comprises polymerizing propylene alone or together with a small amount of other .alpha.-olefin in the presence of a catalyst comprising a titanium-containing solid catalyst component and an organoaluminum compound, and then polymerizing the resulting propylene polymer with an .alpha.-olefin other than propylene, alone or together with propylene in a gas phase without deactivating the catalyst, characterized in that the gas phase polymerization is conducted in the presence of a siloxane or a polysiloxane in an amount of from 1.times.10.sup.-6 to 0.1 by weight ratio relative to the weight of said propylene polymer.

Abstract: The present invention relates to a process for producing a polypropylene-ethylene block copolymer by a continuous multi-stage polymerization comprising a first stage in which polypropylene is polymerized in a first polymerization vessel in the presence of a propylene polymerization catalyst, and a second stage in which propylene and ethylene are copolymerized in a second polymerization vessel, wherein the polypropylene slurry discharged from the first polymerization vessel is supplied to a concentrator to separate said slurry into a concentrated polypropylene slurry and a supernatant liquid, the concentrated polypropylene slurry is then introduced through an upper part of a hydraulic sedimentation classifier to be contacted with a countercurrent of the upward flowing of the supernatant fluid introduced through a lower part of said classifier to obtain hydraulically sedimented polypropylene, and non-hydraulically sedimented polypropylene; the thus obtained hydraulically-sedimented polypropylene is then supplie

Abstract: A process for producing a polyolefin characterized by polymerizing an olefin in the presence of a catalytic system composed of solid titanium trichloride, an organic aluminum compound, an aromatic hydrocarbon and a monocarboxylic acid ester having an olefinic double bond or an aromatic ring in the molecule thereof.

Abstract: A solid titanium trichloride, produced by precipitation from a homogeneous solution or mixture with an ether, is treated by prepolymerization with propylene at a partial pressure of less than 1 kg/cm.sup.2. The pretreated titanium trichloride containing a propylene polymer is then admixed with an organoaluminum compound and the admixture is used as a catalyst in the polymerization of propylene.

Abstract: A process for polymerizing an olefin comprises effecting said polymerization in contact with a catalyst of a combination of a first solid component prepared by treating a mixture of (a) a titanium tetrahalide, (b) a vanadyl alcoholate and (c) a vanadyl trihalide, with an organoaluminum compound, and a second component of an organoaluminum compound.