GB720487A - Lubricating greases - Google Patents

Abstract

Metallic salts of acidic copolymers of aliphatic vinyl compounds and a ,b -unsaturated polycarboxylic acids or anhydrides are added to lubricating oils as gelling agents to form lubricating greases. The vinyl compounds may be a -olefines, R - CH = CH2, where R is an alkyl radical having 1- to 30 carbon atoms, such as 1-dodecene, 1-hexadecene, 1-octadecene, and the higher olefines obtained by the thermal cracking of petroleum wax or waxy petroleum stocks; allyl esters R.COOCH2.CH=CH2 such as allyl laurate, myristate, palmitate, stearate and mixed allyl esters of hydrogenated fish oil fatty acids, or allyl esters of mixtures of stearic with oleic or linseed oil acids; allyl ethers, e.g. allyl methyl, amyl, heptyl, lauryl and hexadecyl ethers and methallyl butyl, octyl and octadecyl ethers, vinyl esters and vinyl ethers. Preferred polycarboxylic acids are maleic, fumaric, itaconic, glutaconic, mesaconic, citraconic and aconitic acids. The salts are those of metals of Group I to IV of the Periodic System particularly lithium, calcium, barium and aluminium. The copolymerization is carried out, with or without a solvent such as toluene, xylene, dioxane, and white oil, by heating with catalysts such as benzoyl, p di-t-butyl and lauryl peroxides and cumene hydroperoxide, and the copolymers are neutralized with the oxide, hydroxide or alcoholate of the metal or the alkali metal or ammonium salt may be reacted with the chloride, hydroxide, or carbonate of the metal whose salt is required. Examples are given of the preparation of allyl stearate-maleic anhydride, allyl stearate and oleate-maleic anhydride, allyl laurate-maleic anhydride, octadecene-maleic anhydride copolymers and a copolymer of the allyl ester of hydrogenated fish oil fatty acids with maleic anhydride. The salts may be formed in situ in the mineral oil vehicle, e.g. of a naphthenic paraffinic, or mixed base type, which may be replaced wholly or in part by synthetic oils of polyester, e.g. 2-ethyl hexyl sebacate, polyether, e.g. polyalkylene glycol, silicone, e.g. methyl polysiloxane, or polymer oil types, e.g. polyethylene. In a modification salts may be formed from a mixture of the copolymer with a saturated aliphatic monocarboxylic acid containing 10-22 carbon atoms, e.g. cupric, lauric, stearic, hydroxystearic and hydrogenated fish oil fatty acids. In a further modification, 1 to 2 per cent of an aliphatic monocarboxylic acid having less than 6 carbon atoms in the molecule, e.g. formic, acetic, butyric and valeric acids, may also be included and the resulting grease has a higher drop point. Additives such as rubber latex, polyisobutylene, acrylic ester polymers, sulphurized sperm oil, phenyl a -naphthylamine, phenothiazine, carbon black and silica flour may be included in the grease. U.S.A. Specifications 2,197,263 and 2,417,433 are referred to.ALSO:Lubricating greases comprise a lubricating oil and a metallic salt of an acidic copolymer of a long chain aliphatic vinyl compound and an a , b -unsaturated polycarboxylic acid or anhydride as gelling agent. The vinyl compounds may be a -olefines, R-CH=CH2, where R is an alkyl with 10-30 carbon atoms, such as 1-dodecene 1-hexadecene, 1-octadecene, and the higher olefines obtained by the thermal cracking of petroleum wax or petroleum stock; allyl esters, R.COOCH2 CH=CH2, such as allyl laurate, myristate, palmitate, stearate and mixed allyl esters of hydrogenated fish oil fatty acids, or allyl esters of mixtures such as stearic and oleic, and stearic and linseed oil acids; and allyl ethers, e.g. allyl methyl, amyl, heptyl, lauryl, hexadecyl ethers and methallyl, butyl, octyl and octadecyl ethers. Polycarboxylic acids mentioned are maleic, fumaric, itaconic, glutaconic, mesaconic, citraconic and aconitic acids and the salts are those of metals of the Periodic Groups I to IV, particularly lithium, calcium, barium and aluminium. Examples show the preparation of greases using Li, Ba, Ca, Al and Zn salts of a copolymer of allyl stearate with maleic anhydride; a calcium salt of a copolymer of allyl stearate and oleate with maleic anhydride; barium salts of a copolymer of allyl laurate and maleic anhydride; a calcium salt of a copolymer of an allyl ester of hydrogenated fish oil fatty acids and maleic anhydride; and the barium salt of an octadecene-maleic anhydride copolymer. In a modification, salts may be formed from a mixture of the copolymer with a saturated aliphatic monocarboxylic acid containing 10-22 carbon atoms, e.g. capric, lauric, stearic, hydroxystearic acids and hydrogenated fish oil fatty acids. The salts may be formed in situ in the mineral oil vehicle, e.g. of naphthenic, paraffinic or mixed base type, which may be replaced wholly or in part by synthetic oils of polyester, e.g. 2-ethylhexyl sebacate, polyether e.g. polyalkylene glycol, silicone e.g. methyl polysiloxane, or polymer oil types e.g. polyethylene. In a further modification, 1-2 per cent. of an aliphatic monocarboxylic acid having less than 6 carbon atoms in the molecule, e.g. formic, acetic, butyric and valeric acids, may also be included and the resulting grease has a higher drop point. The acidic copolymer and the higher molecular weight fatty acid are blended in an oil base by heating to about 150 DEG F. The low molecular weight acid and sufficient metallic oxide, hydroxide or salt to neutralize the three acidic components together with a small amount of water is added and the mixture stirred and heated at 300-400 DEG F. to permit saponification and dehydration to take place, the grease is then cooled. Additives such as rubber latex, polyisobutylene, acrylic ester polymers, sulphurized sperm oil, phenyl a -naphthylamine, phenothiazine, carbon black and silica flour may be included in the grease. U.S.A. Specifications 2,417,433 and 2,197,263 are referred to.