| 摘要 |
2109210 9219659 PCTABS00017 The invention relates to a method for the preparation of polyolefins by polymerizing olefin by using a procatalyst composition prepared by bringing together magnesium chloride, a lower alcohol, a titanium compound, and phthalic acid ester. The invention also relates to the said procatalyst composition. The invention has succeeded in lowering the concentrations of titanium and phthalic acid ester in the catalyst, and thereby also in the polyolefin, and at the same time in preparing large-pore polyolefin, which is important for certain purposes. These properties have been obtained by using a procatalyst of the said type, in the preparation of which a transesterification has been performed between the lower alcohol and the phthalic acid ester, and the phthalic acid ester selected for the transesterification is one the alkoxy group of which has at minimum 10 carbon atoms.
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