| 摘要 |
PCT No. PCT/FI91/00391 Sec. 371 Date Aug. 16, 1993 Sec. 102(e) Date Aug. 16, 1993 PCT Filed Dec. 17, 1991 PCT Pub. No. WO92/11296 PCT Pub. Date Jul. 9, 1992.The invention relates to a process for the preparation of a solid procatalyst composition of a catalyst system for the polymerization of olefins wherein a magnesium halide such as magnesium chloride is dissolved and/or suspended into an alkyl ester of a monocarboxylic acid such as ethyl acetate, impregnated to a carrier, treated with an organometallic compound or a silicon compound and thereafter with a transition metal compound. The invention also relates to a procatalyst composition and its use together with a cocatalyst for the polymerization of olefins. The activity has been enhanced according to the invention by the use of a carrier containing hydroxyl groups, which carrier is kept at a temperature of at most about 200 DEG C. prior to the impregnation so that the hydroxyl groups are retained in the carrier to an essential extent until the impregnation step. The carrier is preferably silica which is treated thermally at 100 DEG -200 DEG C. so that the water present is removed but the hydroxyl groups are retained to a considerable extent. The organometal compound is preferably an aluminumalkyl compound such as triethylaluminum, and the transition metal compound is preferably titanium tetrachloride.
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