A method for the preparation of lithium, calcium soaps - - - greases

摘要

A lubricating grease composition comprises a lubricating oil thickened to a grease consistency with a mixture of lithium and calcium soaps of fatty acids, the molar ratio of lithium soap to calcium soap in the mixture being between 2:1 and 8:1, the grease composition having been prepared by a process comprising the step of heating and mixing the soaps with the oil at a dehydration temperature below the melting temperature of the finished grease and cooling the grease so dehydrated. The lubricating oil may be mineral oil, an ester of a dibasic acid (e.g. an ester of adipic or sebacic acid), a complex ester (formed, for example, by reacting an alcohol, a glycol and a dibasic acid) an ester of monobasic acid, a polyether, or a polymerized olefin. The soaps may be derived from stearic, oleic, or hydroxy stearic acids, hydrogenated fish oil acids or beef or mutton tallow fatty acids. The lubricating grease composition may contain additional ingredients such as oxidation inhibitors (e.g. phenyl alpha-napthylamine), colour agents and tackiness agents, and the finished grease may contain free alkalinity. The cooling of the dehydrated grease may be effected by the addition of cold lubricating oil, and the cooled grease is preferably subjected to high rates of shear (e.g. in excess of 100,000 reciprocal seconds) in a milling or homogenizing device. In the examples, the preparation of greases according to the invention is described, the ingredients employed being mineral lubricating oil, tallow fatty acids (or cotton-seed oil fatty acids or hydrogenated fish oil fatty acids) lithium hydroxide monohydrate and hydrated lime. In a further example, a grease according to the invention is prepared from di - 2 - ethylhexyl sebacate, tallow fatty acids, lithium hydroxide monohydrate and hydrated lime.