| 摘要 |
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 SiO2 x m Al2O3 x 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 (2.2) a solution of a particular chromium compound (component c), with intimate mixing and evaporation of the solvent, and (3) finally heating the product, obtained from stage (2), in an anhydrous stream of gas containing oxygen, with the proviso that the product obtained from stage (1) or from stage (2) is dried and comminuted before it is used further in the next stage. This process makes it possible to influence the essential properties of the polymers in relatively diverse ways, in the desired direction, by relatively slight modifications of the catalyst.
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