GB721285A - Lubricating composition - Google Patents

Abstract

A lubricating composition, particularly suitable for use in gears and bearings operating under conditions of extreme pressure, high speed and high temperatures, comprises a lubricating oil having incorporated therein a minor proportion of a heat-polymerizable organic compound containing a plurality of hydroxyl groups (including hydroxyl groups present in a carboxyl group and carbonyl groups which are capable of forming hydroxyl groups by a keto-enol tautomerization) which is substantially insoluble in the lubricating oil, or of a pre-polymerized product thereof, and sufficient of an oil-soluble non-ionic solubilizer to solubilize the heat-polymerizable compound or its pre-polymerized product in the lubricating oil. The lubricating oil may be a mineral oil or a synthetic oil such as polymerized olefin, alkylated aromatic, silicone polymer (e.g. dimethyl silicone polymer), H2S-adduct of an unsaturated ether or thioether, or di(2-ethyl-hexyl)sebacate. Mixtures of natural and synthetic oils may be employed and minor proportions of fixed oils such as castor oil or lard oil may be blended with the natural and/or synthetic oil. The heat-polymerizable organic compound may be tartaric, hydroxy malonic, hydroxy glutaric, hydroxy adipic, malic, tartronic, oxalacetic, citraconic, mesaconic, aconitic, maleic, fumaric, itaconic, glutaric, adipic, pimelic, sebacic, azelaic, suberic, laevulinic, pyruvic, acetoacetic, glyoxylic, hydroxy butyric, glycollic, lactic or homoterephthalic acid, or p mixtures of these acids. Any of these acids may be modified by esterification with a polyhydric alcohol such as ethylene, diethylene, triethylene, propylene or dipropylene glycol. Mixtures of the free acids and polymerized or polymerizable esters of the acids, particularly those esters derived from polyhydric alcohols, may also be employed. Other heat-polymerizable organic compounds which may be employed are carbohydrates and derivatives thereof, particularly pentoses and hexoses (e.g. ribose, arabinose, glucose, fructose, galactose and mannose), amino-sugars, degenerated cellulose, degenerated ethyl-cellulose, hexitols (e.g. sorbitol and mannitol) and salicylal glucosamine. Non-ionic solubilizers which may be employed are lauryl or oleyl alcohol, 4-tertiary butyl cyclohexanol, phosphatides, organic oxides preferably the monoethers of polyalkylene glycols, and esters preferably the oil-soluble partial esters of polyhydric alcohols. Ionic solubilizers may be employed in conjunction with the non-ionic solubilizers. Suitable ionic solubilizers are amines, heterocyclic nitrogen compounds particularly glyoxalidine compounds, quaternary ammonium compounds, soaps, sulphonates and sulphates. The lubricating compositions may contain additional ingredients such as blooming agents, pour point depressants, viscosity improvers, antifoaming agents, antioxidants, corrosion inhibitors, anti-rusting compounds and wear-reducing agents; many specific additional ingredients are listed. In the examples a large number of lubricating compositions are specified wherein the lubricating oil is chosen from mineral oil, alkyl naphthalenes of boilng point 200-500 DEG C. (the alkyl radicles being tert.-C4-C12 alkyl radicles) and polybutene oil; the heat polymerizable organic compounds or their pre-polymerized products being chosen from tartaric, lactic, malic and gluconic acids, partial ester of glycerol and succinic acid, polymerized partial ester of tartaric acid and sorbitol, polymerized partial ester of malic acid and propylene glycol, polymerized partial or diester of tartaric acid and propylene glycol and polymerized ester of ethylene glycol tartrate and glycerol; the non-ionic solubilizers being chosen from sorbitan monooleate and monostearate, polyoxyethylene sorbitan monooleate, glycerol monooleate, polyoxyethylene glycerol monooleate, pentaerythritol monooleate and polyoxyethylene pentaerythritol monooleate; and the ionic solubilizers being chosen from 1-hydroxyethyl-2-heptadecenyl glyoxalidine, 1-hydroxyethyl-2-heptadecenyl glyoxalidine lactate, 1-hydroxyethyl-2-heptadecyl glyoxalidine, C10-C18 aliphatic amines known under the trade name "Armeen 2C" and oil-soluble sodium and calcium petroleum sulphonates.