GB1152123A - Process for the Continuous Manufacture of Polyethylene of High Molecular Weight - Google Patents

Abstract

1,152,123. Continuous polymerization of ethylene. FARBWERKE HOECHST A.G. 10 March, 1967 [10 March, 1966], No. 11490/67. Heading C3P. A process for the continuous manufacture of polyethylene or a copolymer of ethylene with up to 10% by weight of propylene or butene-1, in an inert dispersing agent or in the gaseous phase, in the presence of a catalyst system comprising (a) a chlorine-containing trivalent titanium compound (prepared as described below) and (b) an aluminium tri-(C 1-10 hydrocarbyl) and/or di-(C 1-10 hydrocarbyl) aluminium hydride, the catalyst concentrations being 0À005 to 0À05 millimoles of titanium compound and 0À01 to 10 millimoles of aluminium compound per litre of dispersing medium or per 0À5 litre of the volume of the reactor, comprises reacting the trivalent titanium compound in the presence of aluminium compound at a temperature of -30‹ to +500 C. in an inert dispersing agent with 0À1 to 10 grams of ethylene per 1 millimole of titanium compound, and using the catalystpolymer mixture obtained from this "prepolymerization" for the main polymerization at a pressure of 1 to 10 atmospheres, a temperature of 60‹ to 120‹ C. and in the absence of air or moisture. The trivalent titanium compound is obtained by reduction of titanium tetrachloride or chloralkoxy titanate of formula Ti(OR) 4-n Cl n in which R is an alkyl or aryl group having 1 to 6 carbon atoms and n is 1 to 4, with an alkyl aluminium sesquichloride and/or a dialkyl aluminium monochloride in an inert dispersing agent at a temperature of - 20‹C. to +30‹ C., followed by ageing at a temperature of 60‹ to 150‹ C. and, if desired, washing with an inert dispersing agent. In the examples, ethylene homopolymers are obtained using TiCl 3 (from TiCl 4 and (C 2 H 5 ) 3 Al 2 Cl 3 )/Al(C 2 H 5 ) 3 catalysts and hexane or a Diesel fuel fraction as inert dispersing agent.