Sulfurized metallic dithiophosphates and their use as additives for lubricating oils

Claim 1

A sulfurized metallic dithiophosphate comprising the product obtained by sulfurization of a composition containing: (A) from about 100 to 20 percent of a metallic dithiophosphate of formula (I): ##STR11## in which formula: R 1 represents: (a) a linear or branched alkenyl radical containing from about 2 to 24 carbon atoms; (b) an unsaturated cycloaliphatic or polycycloaliphatic radical containing from about 3 to 20 carbon atoms; R 2 and R 3 are similar or different and represent an alkyl radical containing from about 1 to 12 carbon atoms; m represents the valence of the metal M; M represents a metal of group IIB, IIIB, IVB, or VIII of the Periodic System of the Elements; and (B) from about zero to 80 percent of an alkyl ester of formula (II): (II)R.sub.4 --COOR.sub.5 in which: R 4 represents a linear or branched alkenyl radical containing from about 2 to 24 carbon atoms, and R 5 represents an alkyl radical containing from about 1 to 12 carbon atoms, by means of a sulfurization agent in an amount corresponding to a weight of sulfur of between about 0.5 and 10 percent, referred to the weight of composition to be sulfurized.