Abstract: Easily pourable polyolefin granules are obtained by polymerizing an olefin in the presence of a polymerization catalyst system comprising a compound having a main catalyst component supported on a spheroidal particle, 1 to 1,000 .mu. in diameter, of a high molecular compound used as a carrier, and an organometallic compound under a pressure of 100 kg/cm.sup.2 or less and at a temperature lower than both of the melting points of the resulting polymer and the said high molecular compound used as a carrier. The granule diameter of the said polyolefin can be controlled very easily by changing the particle size of the high molecular compound used as a carrier, the loading rate of the main catalyst component on the high molecular compound used as a carrier, or the catalyst efficiency. The granule size distrubution can be controlled by controlling the particle size distribution of the high molecular compound used as a carrier. The polyolefin granules obtained have a bulk density of 0.4 to 0.

Abstract: A process for the manufacture of olefin polymers by polymerizing .alpha.-monoolefins of 2 to 8 carbon atoms by means of a catalyst which is obtained from a silicon-containing material (component a), an organo-metallic compound containing alkyl groups (component b) and a chromium compound (component c), wherein the catalyst employed is obtained by (1) first bringing into contact (1.1) an alkogel (component a) of the empirical formula SiO.sub.2 .multidot. m Al.sub.2 O.sub.3 .multidot. n ROH, where m is a number from 0 to 2, n is a number such that the content of ROH in the alkogel is from 1 to 85 per cent by weight and R is alkyl of 3 to 8 carbon atoms, and (1.2) an aluminum compound containing certain alkyl groups (component b), with intimate mixing, to form a solid-phase reaction product, (2) then bringing into contact (2.1) the solid-phase reaction product obtained from stage (1) and (2.

Abstract: Alpha olefins are polymerized alone or in admixture at comparatively low pressures to produce polymers employing a two-component catalyst wherein one component is an organozinc or organomagnesium compound, e.g. zinc diethyl, magnesium diphenyl, propyl magnesium chloride, etc. The other component is a salt, oxide or hydroxide of a metal of Group IV-B, V-B or VI-B of the Periodic System, including thorium and uranium.

Abstract: Olefin polymerization catalysts are prepared by depositing a chromium compound and an aluminum compound on an inorganic support material and heating the support material in a non-reducing atmosphere at a temperature above about 300.degree. C up to the decomposition temperature of the support material. The supported chromium and aluminum compound is then combined with a metallic and/or non-metallic reducing agent, to provide a catalyst system useful in the polymerization of 1-olefins.

Abstract: Ethylene homopolymers and copolymers are made in a particle form process over a mixed catalyst comprising several portions of the same or different supported chromium components and metal promoted variations thereof in which each portion is activated at a different temperature, thereafter combined, and the composite, or each activated portion before being combined, is post treated with a hydrocarbyl aluminum hydrocarbyloxide. Broad molecular weight polymers are produced having excellent die swell characteristics and acceptable environmental stress cracking resistance and flow properties; this is achieved and while at the same time realizing high productivities.

Abstract: An olefin polymerization catalyst comprising a chromium compound deposited on a carrier, which chromium compound is complexed with a straight-chain, branched-chain, or cyclic aliphatic hydrocarbon or mixture thereof such that the mol ratio of aliphatic hydrocarbon to chromium compound is 1:2-3, said chromium compound being deposited on said carrier material in an amount between 10.sup..sup.-3 and 10 millimols chromium compound per gram of carrier material, said carrier material also containing a trialkyl, tricycloalkyl, triaryl, monohalodihydrocarbyl, or monoalkoxydihydrocarbyl aluminum compound; a process for preparing such an olefin polymerization catalyst and the use of such catalyst in the polymerization of olefins, particularly ethylene, propylene, 2-methylpropylene and butene-1.

Abstract: In a process for producing olefin polymers, a hydrocarbylaluminum hydrocarbyloxide such as diethylaluminum ethoxide is introduced into the reaction zone in a stream separate from the catalyst to reduce fouling.