GB589393A - Improved process for the low temperature polymerization of olefinic materials - Google Patents

Abstract

A polymerization process comprises mixing isobutylene and a polyolefin having from five to fourteen carbon atoms per molecule with a hydrocarbon refrigerant and from 0.001 per cent to 1.0 per cent by weight of the olefinic mixture of an ether as polymerization promoter at a temperature between -20 DEG and -165 DEG C., delivering the mixture to the first stage of a cold cascade kneader polymerizer and polymerizing the mixture in the presence of a Friedel-Craft catalyst and under the influence of the pulling action of kneader blades. It is preferred that the isobutylene is present in a major proportion while specified polyolefins are 2,3 - dimethyl butadiene - 1 : 3, isoprene, piperylene, myrcene and dimethallyl. Specified ethers are dimethyl, diethyl and isopropyl ether, and specified hydrocarbon refrigerants are liquid ethylene, ethane, propane and a mixture of liquid propane and liquid carbon dioxide. The preferred catalyst is boron trifluoride either in the form of a gas or in solution in a portion of the hydrocarbon refrigerant, while other specified catalysts are the double salts of aluminium chloride and aluminium bromide, of aluminium chloride and aluminium ethoxide, and of titanium tetrachloride and aluminium ethoxide. The preferred temperature is from -40 DEG to -103 DEG C. Referring to the Figures, three cascade kneaders 2 of the Werner and Pfleiderer type have mixing blades 3 in each thereof. All three kneaders have cover-plates 4, 5 and 6 provided with sight glasses 7, 8 and 9 respectively, while the first and second have gate members 11 controlled by rods 12 and hand wheels 14 to adjust the rate of delivery of polymer. An extruder member 15 with extruder screws 17 delivers the polymer through the outlet member 18 and is surrounded by a steam jacket 19. The reaction mixture is delivered through supply pipe 21 to kneader blades 2 driven by shaft members 23, the catalyst enters through pipe 26 or less preferably through pipe 25, while volatile matter is discharged through outlet 27. Examples are given of the copolymerization of isobutylene and 2,3-dimethyl butadiene-1 : 3 in the presence of diethyl ether with boron trifluoride as catalyst and (1) and (3) liquid <PICT:0589393/IV/1> <PICT:0589393/IV/2> ethylene, (2) liquid ethane, and (4) a hydrocarbon mixture also containing carbon dioxide. These products were compounded with stearic acid, zinc oxide, carbon black, sulphur, tetramethyl thiuram disulphide, paraquinone dioxime and mercaptobenzothiazole and cured.