| 摘要 |
One or more olefines are polymerized in the presence of a Friedel-Crafts catalyst together with a reducing metal, the process being carried out in two stages:-(1) preopolymerization in contact with catalyst alone or mixed with an inert diluent in an amount of up to 10 times the weight of the catalyst, until the weight of the prepolymer is in the range from 2 to 10 times the weight of the catalyst and (2) final polymerization after the addition of the inert diluent or the remaining portion thereof to the prepolymerization product. The term "Friedel-Crafts catalyst" means the halide of a metal or of boron, having an acidic character, and particularly AlCl3, TiCl3 and BF4. The inert diluent may be an aliphatic, cyclic or aromatic hydrocarbon or liquid polyethylene. The preferred catalyst is a mixture of anhydrous aluminium trichloride, powdered aluminium and titanium trichloride. The prepolymerization is preferably carried out between 120 DEG and 170 DEG C. under a pressure of 40 to 80 kg./cm.2, and the final polymerization, which may be in the same or a different reaction vessel, between 70 DEG and 120 DEG C. and under a pressure of 20 to 40 kg./cm.2. In the examples ethylene and propylene homo- and copolymers with each other are prepared.
|
