GB798457A - Copolymer composition - Google Patents

Abstract

Lubricating compositions comprise a lubricating oil, particularly a mineral oil, together with a small proportion of a copolymer having an apparent molecular weight of at least 2000 and derived from (A) from 75 to 97 mol. per cent of at least one copolymerizable ethylenically unsaturated compound having at least one aliphatic hydrocarbon group containing 4 to 30 carbon atoms, (B) from 25 to 3 mol. per cent of at least one ester of an aliphatic alpha, betaunsaturated monocarboxylic acid and a poly-1,2-alkylene glycol having a molecular weight between 106 and 10,000 and, optionally, (C) from 0 to 5 mol. per cent of at least one aliphatic alpha, beta-unsaturated monocarboxylic acid, the total content of the (C) component not exceeding 25 mol. per cent of the total number of (B) and (C) units in the copolymer, the unsaturated acids of these units containing not more than 7 aliphatic carbon atoms, and the alpha and/or beta carbon atoms thereof being unsubstituted or substituted by an alkyl group containing not more than 4 carbon atoms. Monomers of types (A), (B) and (C) are listed (see Group IV (a)), representative copolymers being:-dodecyl methacrylate/diethylene glycol monomethacrylate, dodecyl methacrylate/polyethylene glycol 200 monomethacrylate, tridecyl methacrylate/polyethylene glycol lauryl monoether methacrylate, octadecyl methacrylate/diethylene glycol monoethyl ether methacrylate, lauryl methacrylate/polyethylene glycol lauryl monoether methacrylate/methacrylic acid, vinyl 2-ethylhexyl ether/polypropylene glycol tridecyl monoether methacrylate/methacrylic acid, (alkylphenoxy) - ethyl methacrylate/polyethylene glycol lauryl monoether methacrylate, lauryl acrylate/polyethylene glycol lauryl monoether acrylate/acrylic acid and allyl stearate/lauryl methacrylate/polyethylene glycol lauryl monoether methacrylate/methacrylic acid.ALSO:Copolymers having apparent molecular weights of at least 2,000 are derived from: (A) from 75 to 97 mol. per cent of at least one copolymerizable ethylenically unsaturated compound having at least one aliphatic hydrocarbon group containing 4 to 30 carbon atoms; (B) from 25 to 3 mol. per cent of at least one ester of an aliphatic alpha, beta-unsaturated monocarboxylic acid having not more than 7 carbon atoms and a poly-1,2-alkylene glycol having a molecular weight between 106 and 10,000 and, optionally (C) from 0 to 5 mol. per cent of at least one aliphatic alpha, beta-unsaturated monocarboxylic acid having not more than 7 carbon atoms, the total content of the (C) component not exceeding 25 mol. per cent of the total number of (B) and (C) units in the copolymer, the alpha and/or beta carbon atoms of the acids of the (B) and (C) units being unsubstituted or substituted by an alkyl group containing not more than 4 carbon atoms. Monomers (A) listed include aromatic and aliphatic olefines, unsaturated ethers and esters of unsaturated alcohols and acids; monomers (B) specified are esters of acrylic, methacrylic, crotonic, tiglic, angelic, alpha-ethylacrylic, alpha - methyl crotonic, alpha - ethylcrotonic, beta - ethylcrotonic, alpha - butylcrotonic, hydrosorbic, alpha-ethylhydrosorbic and alpha-propylhydrosorbic acids with polyethylene and polypropylene glycols such as diethylene, pentaethylene, monaethylene and tetra-1,2-propylene glycols and monoalkyl ethers of polyethylene glycol; the formul of other suitable polyglycols are provided, including those substituted by carboxyl, ester, hydroxyl, nitro, mercapto, amino and amido groups; monomers (C) specified are acids of the type used in the formation of the (B) esters. The copolymers may be formed by the copolymerization of the monomeric ingredients in bulk, solution or emulsion in the presence of catalysts such as benzoyl, acetyl, di-tert.-butyl and di-tert.-amylperoxides, tert.-butylhydroperoxide, 1,11 - azocyclohexanecarbonitrile and azodiisobutyronitrile. During polymerization, additional catalyst and solvent, if employed, may be added as the reaction proceeds. Alternatively, the copolymers may be prepared by appropriate treatment of a preformed polymer. In examples: (1) polydodecyl methacrylate is partially hydrolysed with KOH, the salt groups are then converted to carboxyl groups which are esterified with diethylene glycol; (2) the procedure of the preceding example is repeated but with the use of polyethylene glycol of mol. wt. 200 as the esterifying agent; (3-8) mixtures of various monomers are copolymerized directly in bulk; (9) allyl stearate and methacrylic acid are copolymerized in bulk and the resulting copolymer is then partially esterified with a mixture of lauryl alcohol and the lauryl monoether of polyethylene glycol. The copolymers are used as additives to lubricating and fuel oils.