摘要:
Disclosed is a catalyst for polymerizing .alpha.-olefins which comprises(A) a composition obtained by co-comminuting(a) a magnesium halide,(b) an organic acid ester,(c) a halogenated aliphatic or alicyclic hydrocarbon,(d) at least one ingredient selected from the group consisting of aliphatic hydrocarbons, alicyclic hydrocarbons, aromatic hydrocarbons, halogenated aromatic hydrocarbons, liquid propylene oligomers and aromatic ethers, and(e) an aluminum halide optionally added thereto and then heat-treating the resulting mixture together with titanium tetrachloride;(B) an organic aluminum compound; and(C) an organic acid ester or a complex thereof with an aluminum halide.
摘要:
A catalyst for polymerizing .alpha.-olefins composed of a titanium composition formed by heating a co-comminuted mixture of a magnesium halide and a complex of an aluminum halide and a carboxylic acid ester of the formula R.sup.1 COOR.sup.2, with titanium tetra-chloride; and an organic aluminum compound of the formula AlR.sup.3 mH.sup.3 --m; and optionally added thereto at least one component selected from an alkyl aluminum halide of the formula AlR.sup.4 nX.sub.3 --n; a carboxylic acid ester of the formula R.sup.5 COOR.sup.6 ; and its complex formed with an aluminum halide; is disclosed.
摘要:
In producing a low density polyethylene by a slurry copolymerization of ethylene and an .alpha.-olefin with use of a catalyst consisting of a magnesium compound-supported titanium and/or vanadium compound and an organoaluminum compound, a certain amount of ethylene is subject to a pre-polymerization in the presence of said catalyst prior to the copolymerization. Successively, the slurry copolymerization of ethylene and an .alpha.-olefin is effected in a low-boiling diluent to obtain a low density polyethylene of 0.925-0.950 in density, covering various grades in a wide range.
摘要:
Ethylene is polymerized or copolymerized with an .alpha.-olefin in the presence of a catalyst consisting of(A) a co-comminuted composition of:(a) a titanium compound;(b) a magnesium halide; and(c) a siloxane polymer; and(B) an organoaluminum compound.
摘要:
An oil-in-water emulsion containing a xanthine derivative represented by or its pharmacologically acceptable salt, wherein the xanthine derivative or salt is present within an oil phase of the emulsion.
摘要:
A process for the preparation of alkylsilanes and alkenyl silanes by hydrosilylation of their corresponding silanes and unsaturated hydrocarbons in the presence or absence of a catalyst. A process for the preparation of polyalkenylsilanes (some of which are novel high molecular compounds) by the anionic coordination polymerization, radical polymerization or ionic polymerization of the alkenylsilanes. A process for the production of silicon carbide by using these polyalkenylsilanes as prepolymers.
摘要:
An axially non-symmetric article is forged by the first upsetting by means of the first and second punches and by the second die-lateral extruding of a metal bar stock which is extruded via an orifice into an extension space(s) which has a greater cross section than the orifice.
摘要:
A catalyst has high activity and is suitable for use in producing chlorine by oxidizing hydrogen chloride with oxygen. The catalyst includes copper, an alkali metal and a rare earth and has pores of which pores having a diameter of 5 to 15 nm have a pore volume of 0.4 to 2.0 ml/g.
摘要:
A method for preparing a highly heat-resistant and burning-resistant poly(silyleneethynylene phenyleneethynylene) having a repeated unit represented by the following structural formula (1A): ##STR1## wherein the phenylene group may be in the o-, m- or p-form, R represents a halogen atom or an alkyl group, alkoxy group, phenoxy group, alkenyl group, alkynyl group, aromatic group, disubstituted amino group or silanyl group; n is an integer ranging from 0 to 4; and R' represents a hydrogen atom, an alkyl group, alkenyl group, alkynyl group or aromatic group, a product obtained by the method and a hardened product obtained by heat-treating, at a temperature ranging from 50.degree.to 700.degree. C., the poly(silyleneethynylene phenyleneethynylene).
摘要:
The present invention relates to a novel ethylene/pentene-1 copolymer whose molded film has a good balance between impact resistance and tear properties and high transparency, also is prominently reduced in a variation of the transparency even after subjected to a heat treatment, and further shows high blocking resistance, provided that the copolymer fulfills specific requisites. The invention also relates to a process for the preparation of the above-mentioned ethylene/pentene-1 copolymer and a formulation of the ethylene/pentene-1 copolymer composition using a stabilizer. According to the invention, there can be obtained an ethylene/pentene-1 copolymer composition which is excellent in heat stability in the molding stage, long-term heat stability and weatherability.