GB960232A - Process for the manufacture of olefine polymers and copolymers having a high bulk density in the pulverulent state - Google Patents

Abstract

Ethyl titanium trichloride is made from titanium tetrachloride and diethyl aluminium monochloride or ethyl aluminium sesquichloride by dissolving the reactants in an inert hydrocarbon solvent, mixing the solutions with stirring at a temperature in the range of 0 DEG C. to 20 DEG C., and ensuring during the reaction that the molar ratio of TiCl4 to monochloride is at least 1, isolating the reaction product, removing monoethyl aluminium dichloride from it by washing or treatment with Al(C2H5)3, and recovering TiCl3.C2H5.ALSO:Polymers of olefins of bulk density exceeding 430 grams per litre are made by polymerizing one or more of the olefins in the presence of a catalyst system comprising a liquid dispersing agent, diethyl aluminium monochloride, and a Ti-containing compound which has been prepared from TiCl4 and diethyl aluminium monochloride or aluminium ethyl sesquichloride by (a) dissolving each of the reactants in an inert solvent to give solutions containing 14 to 60% by weight of each reactant, (b) maintaining at any time in the reaction vessel a molar ratio of TiCl4 to diethyl aluminium monochloride of at least 1, (c) maintaining the molar ratio of Ti-compound formed to the Al-compound less than 2, (d) effect the reaction at a temperature of 0 DEG to 20 DEG C., and (e) keeping the reactants well stirred. The polymerization is continued until the phase ratio (by weight) of the liquid dispersing agent to the solid polymer is less than 1.6. The Ti-containing compound may be separated from the reaction mixture and washed with an inert solvent in which the aluminium monoethyl dichloride is soluble. Before separation, the Ti-containing compound may be subjected to a thermal treatment at a temperature within the range of 40 to 150 DEG C., and then treated with aluminium triethyl in an amount sufficient to convert substantially all the aluminium monoethyl dichloride into diethyl aluminium monochloride. The olefin may be ethylene, propylene, butene, 4-methyl-pentene-(1), pentene-(1), or styrene. The dispersing agent is preferably a hydrocarbon solvent. The olefin may be mixed with a small amount of hydrogen. Exemplified polymers are polyethylene, polypropylene, poly-4-methyl-pentene-(1), and copolymers of ethylene and propylene. The polymers may be recovered by conventional techniques such as addition of butanol, and steam-distillation. Specifications 799,392, 799,823, 801,862 and 826,639 are referred to.