Process for preparing polyolefins

Claim 1

A process for preparing polyolefins by polymerizing or copolymerizing alpha- olefins at a temperature in the range of from 20° to 120° C and at a pressure in the range of atmospheric pressure to 70 Kg/cm. 2 G., in the presence of a catalyst comprising a solid component and an organometallic compound component, characterized in that said solid component is obtained by copulverizing (1) a magnesium dihalide and/or a manganese dihalide, (2) an aromatic hydrocarbon selected from the group consisting of monocylic aromatic hydrocarbon and the halogen-and/or alkyl-substituted derivatives thereof and polycyclic aromatic hydrocarbon, the ratios of magnesium dihalide and/or manganese dihalide to said aromatic hydrocarbon being in the range of from 1:0.5 to 1:0.1, (3) a tetravalent titanium compound represented by the general formula Ti(OR) n X 4-n wherein R is an alkyl, allyl, aryl or aralkyl group having 1 to 20 carbon atoms, X is a halogen atom and n is a whole number of from 0 to 4, and (4) a trivalent titanium compound selected from the group consisting of titanium trihalides obtained by reducing titanium tetrachloride with hydrogen, aluminum, titanium or an oganometallic compound, and trivalent titanium compounds obtained by reducing tetravalent titanium alkoxyhalides represented by the general formula Ti(OR) n X 4-n wherein R is alkyl, allyl, aryl or aralkyl having 1 to 20 carbon atoms, X is a halogen atom and n is a whole number of from 1 to 4, with an organometallic compound of a metal of the groups I to III of the periodic table present in a molar ration with tetravalent titanium compound (3) of from 50:1 to 1:50 and in that said organometallic compound component is a mixture of (5) a trialkylaluminum and (6) a compound represented by the general formula AlR.sub. n X 3-n wherein R is alkyl having 1 to 10 carbon atoms and may be same or different, X is halogen and 0 < n < 3, said compound being present in a molar ratio with trialkylaluminum (5) of from 2:1 to 1000:1.