PROCESS FOR PREPARING POLYOLEFINS

摘要

A process is provided for preparing polyolefins by polymerizing or copolymerizing olefins in the presence of a novel catalyst comprising a solid component and an organometallic compound component. The solid component is obtained by copulverizing (1) at least one of o magnesium dihalide and a manganese dihalide; (2) an aromatic hydrocarbon selected from the group consisting of monocylic aromatic hydrocarbon, polycyclic aromatic hydrocarbon and at least one of halogen- and alkyl-substituted derivatives thereof, the ratios of at least one of magnesium dithalide and manganese dihalide to the aromatic hydrocarbon being in the range of from 1:0.5 to 1:0.1 (3) a tetravalent titanium compound; and (4) a trivalent titanium compound being present in n molar ratlo with tetravalent titanium compound (3) of from 50:1 to 1:50, and wherein the organometallic compound component is a mixture of (5) a trialkylaluminum; and (6) a compound represented by the general formula A1RnX3-n, wherein R is alkyl having 1 to 10 carbon atoms and may be same of different. X is halogen and 0 < n < 3, the compound being present in 3 molar ratio with trialkylaluminum (5) of from 2:1 to 1000:1. The yield of polymer per solid is remarkably increased when this process is carried out dispensing with the step of removing residual catalyst in the polymer. At the same time the bulk density of the resulting polymer is heightened, the molecular weight distribution thereof is widened and consequently the fluidity of the polymer in a molten state is improved.