Preparation of homopolymers of ethene and copolymers of ethene with higher α-monoolefins using a Ziegler catalyst system

Claim 1

A process for the preparation of homopolymers of ethene and copolymers of ethene with minor amounts of C 3 -C 8 -α-monoolefins by polymerization of the monomer or monomers at from 30° to 200° C. and under from 0.1 to 200 bar using a Ziegler catalyst system consisting essentially of (1) a transition metal catalyst component which is prepared by a method in which (1.1) first (1.1.1) a finely divided, porous inorganic oxide substance (I) which has a particle diameter of from 1 to 1,000 μm, a pore volume of from 0.3 to 3 cm 3 /g and a surface area of from 100 to 1,000 m 2 /g and is of the formula SiO 2 .--aAl 2 O 3 , where a is from 0 to 2, and (1.1.2) a solution (II), as obtained by combining (IIa) 100 parts by weight of a saturated aliphatic or partially saturated aliphatic and partially aromatic oxahydrocarbon which has of 1 or 2 oxaoxygen atoms and more than 3 but less than 19 carbon atoms, and (IIb) from 0.01 to 50 parts by weight of a mixture of (IIb1) 100 molar parts of a vanadium trihalide/alcohol complex of the formula VY 3 .nZ--OH, where Y is chlorine or bromine, n is from 1 to 6 and Z is a monovalent saturated aliphatic or partially saturated aliphatic and partially aromatic hydrocarbon radical of not more than 10 carbon atoms and, (IIb2) from 0.2 to 300 molar parts of a titanium trihalide, where halogen may be chlorine and/or bromine, or of a titanium trihalide complex of the formula TiY 3 .nZ--OH, where Y is chlorine or bromine, n is from 1 to 6 and Z is a monovalent saturated aliphatic or partially saturated aliphatic and partially aromatic hydrocarbon radical of not more than 10 carbon atoms, are brought into contact with one another with formation of the a suspension (III), with the proviso that the weight ratio of inorganic oxide substance (I) to transition metal composition (IIb) is from 1:0.01 to 1:2, and the suspension (III) is evaporated to dryness at below 200° C. and above the melting point of the oxahydrocarbon (IIa) used, with formation of a solid-phase intermediate (IV), and (1.2) then (1.2.1) the solid-phase intermediate (IV) obtained and from stage (1.1) and (1.2.2) an aluminum compound (V) which is dissolved in an organic solvent and is of the formula AlR m X 3-m , where X is a radical OR, chlorine, bromine or hydrogen, R is a C 1 -C 18 -hydrocarbon radical and m is from 1 to 3, are brought into contact with one another with formation of a suspension, with the proviso that the weight ratio of solid-phase intermediate (IV) to aluminum compound (V) is from 1:0.05 to 1:2, the resulting suspended substance being a solid-phase product (VI), (2) an organoaluminum catalyst component of the formula AlR m X 3-m , where X is a radical OR, chlorine or hydrogen, R is a C 1 -C 18 -hydrocarbon radical and m is from 1 to 3, and (3) an organohalogen catalyst component with the provisos that the atomic ratio of transition metal from the catalyst component (1) to aluminum from the catalyst component (2) is from 1:0.1 to 1:500 and the molar ratio of organoaluminum catalyst component (2) to organohalogen catalyst component (3) is from 1:0.001 to 1:50, wherein the transition metal catalyst component (1) used is one prepared by a method in which (1.3) in addition (1.3.1) the solid-phase product (VI) obtained from stage (1.2), which may be in suspension in an inert hydrocarbon, and (1.3.2) oxygen are brought into contact with one another at from -25° to 100° C., for from 5 to 500 minutes, with the proviso that the atomic ratio of transition metal from the product (VI) to oxygen is from 1:0.01 to 1:10, the resulting solid-phase end product (VII) being the transition metal catalyst component (1).