Colloidal products, their preparation and their uses

Abstract

New overbased colloidal products that comprise a core of micellized alkali metal or alkaline-earth metal carbonate, surrounded by a ring of at least one surfactant compound that is selected from among the dihydrocarbyl-dithiophosphoryl-alkane-sulfonic acids, and their salts of alkali metals or alkaline-earth metals are described. They are derived from the carbonation of at least one oxide or hydroxide of an alkali metal or alkaline-earth metal that is carried out within an oily medium that contains hydrocarbon in the presence of at least one dihydrocarbyl-dithiophosphoryl-alkane-sulfonic acid that corresponds to general formula: ##STR1## in which R represents a monovalent aliphatic, cycloaliphatic or aromatic radical that contains 1 to 30 carbon atoms and x has a value of 3 to 6, or an alkali metal or alkaline-earth metal salt of such an acid. These colloidal products can be used as detergent additives notably providing anti-wear and extreme-pressure properties in lubricants. Because of the presence in their molecule of dihydrocarbyl-dithiophosphoric groups, they also exhibit anti-oxidizing properties.

Dependencies are inferred from the claim text.