| 摘要 |
Polymers or copolymers of ethylene are prepared by the low pressure process using as catalyst a reaction product obtained by reducing titanium tetrahalide with dialkyl aluminium hydride and/or trialkyl aluminium, suspended in an inert liquid, the catalyst having been prepared by bringing the components together in an inert liquid in such a way that the atomic ratio in which the titanium and aluminium are present in the inert liquid is maintained constant. It is preferred that the Al/Ti ratio during preparation is maintained at from 0,5 to 1 to 1:1 and during polymerisation at from 1:1 to 2:1 or during preparation at 1:1 to 2:1 and during polymerisation at 0,5 to 1 to 1:1. Specified copolymers are those with propylene, butylene-butadiene and styrene. Specified inert liquids are hexane, heptane, cyclohexane, gasoline, kerosine, heptene, toluene, chlorobenzene, mineral oil fractions and their mixtures.ALSO:A catalyst for the polymerization of ethylene comprises a reaction product obtained by reducing titanium tetrahalide with dialkyl aluminium hydride and/or trialkyl aluminium suspended in an inert liquid, the catalyst having been prepared by bringing the components together in an inert liquid in such a way that the atomic ratio in which the titanium and aluminium are present in the inert liquid is maintained constant. It is preferred that the Al/Ti ratio is maintained at from 0.5:1 to 1:1 or from 1:1 to 2:1. Specified inert liquids are hexane, heptane, cyclohexane, gasoline, kerosine, benzene, toluene, chlorobenzene, mineral oil fractions and their mixtures.
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