Patent GB-689670-A (GB)
Title: Improvements in or relating to viscosity index improvers
IPC: C08F16/12
Filed: 1951-06-13
Abstract: Polymeric materials suitable for use as viscosity index improvers for lubricating oils are prepared by copolymerizing in the presence of a Friedel-Crafts catalyst, a vinyl alkoxy ether of the formula R-[O-R1]n-O-CH=CH2, wherein R is an alkyl group containing 1 to 20 carbon atoms, R1 is a bivalent radical of the group methylene, ethylene, propylene and butylene, and n is 1, 2 or 3, with at least one vinyl alkyl ether of the formula R11-O-CH= CH2, wherein R11 is an alkyl group of 1 to 20 carbon atoms.  R, R1 and R11 are such that the average of R+nR1 and R11 in the resulting copolymer is at least 4 carbon atoms when n=1, at least 6 when n=2 and at least 8 when n=3. Specified alkoxy vinyl ethers are 2-methoxy ethyl-, 2-ethoxy ethyl-, 2-butoxy ethyl-, 3-ethoxy propyl-1-, 2-butoxy 2-methyl ethyl-, 2-isopropoxy methyl ethyl-, 2-propoxy butyl-3-, 2-octyloxy 2-ethyl ethyl-, 2-octyloxy 1-ethyl ethyl-, 2-octyloxy ethoxy-ethoxy ethyl-, hexadecyloxy ethoxy ethyl-, 2-(2-ethyl hexyloxy) ethoxy ethyl-, 2-(2-ethoxy ethoxy) ethyl-, and 2-(2-butoxy ethoxy) ethyl vinyl ethers.  Suitable vinyl alkyl ethers are vinyl isobutyl ether, vinyl 2-ethyl hexyl ether, vinyl methyl ether, vinyl ether of the alcohols known under the Registered Trade Mark "Lorol 8," and vinyl octadecyl ether. It is preferred that the average alkyl chain length in the final copolymer is from 3 to 8 carbon atoms.  Polymerization is preferably effected in bulk using diluents such as hydrocarbons and/or halogenated hydrocarbons, e.g. methyl chloride, to control molecular weight and to facilitate handling.  Temperatures of 0 DEG to - 100 DEG  C. are operable and internal coolants such as ethylene, dry ice or methyl chloride may be used.  Specified catalysts are gaseous BF3, BF3 etherates, AlCl3, SnCl4 and ZnCl2.  The copolymers may be blended with natural or synthetic lubricating oils in amounts of 0.01 to 10 per cent by weight of the total composition.ALSO:Polymeric materials suitable for use as viscosity index improvers for natural and synthetic lubricating oils, particularly mineral oils, are prepared by copolymerizing in the presenc of a Friedel-Crafts catalyst, a vinyl alkoxy ether of the formula R-[O-R1]n-O-CH=CH2, wherein R is an alkyl group of 1 to 20 carbon atoms, R1 is a bivalent radical of the group methylene, ethylene, propylene and butylene, and n is 1, 2 or 3, with at least one vinyl alkyl ether of the formula R11-O-CH=CH2, wherein R11 is an alkyl group of 1 to 20 carbon atoms.  R, R1 and R11 are such that the average of R+nR1 and R11 in the resulting copolymer is at least 4 carbon atoms when n=1, at least 6 when n=2 and at least 8 when n=3. Specified alkoxy vinyl ethers are 2-methoxy ethyl-, 2-ethoxy ethyl-, 2-butoxy ethyl-, 3-ethoxy propyl-1-, 2-butoxy 2-methyl ethyl-, 2-isopropoxy methyl ethyl-, 2-propoxy butyl-3-, 2-octyloxy 2-ethyl ethyl-, 2-octyloxy 1-ethyl ethyl-, 2-octyloxy ethoxy-ethoxy ethyl-, hexadecyloxy ethoxy ethyl-, 2-(2-ethylhexyloxy) ethoxy ethyl-, 2-(2-ethoxy ethoxy) ethyl-, and 2-(2-butoxy ethoxy) ethyl vinyl ethers.  Suitable vinyl alkyl ethers are vinyl isobutyl ether, vinyl 2-ethyl hexyl ether, vinyl methyl ether, vinyl ether of the alcohols known under the Registered Trade Mark "Lorol B," and vinyl octadecyl ether.