Bisdithiophosphoric acid derivatives as lubricant additives

The present invention relates to novel bisdithiophosphoric acid derivatives, to the use thereof as additives in lubricants, machining fluids and hydraulic fluids, and to compositions containing said derivatives. There are disclosed compounds of formula I whereinRand Rare each independently of the other C-Calkyl, C-Ccycloalkyl, C-Ccycloalkylmethyl, C-Cbicycloalkylmethyl, C-Ctricycloalkylmethyl, phenyl,C-Calkylphenyl or, taken together, are Ris C-Calkylene which is interrupted by -O-, -S-, or -NR-, or is a group of formula Ris hydrogen, C-Calkyl, phenyl-C-Calkyl, phenyl or C-Calkyl-substituted phenyl,Ris hydrogen or methyl.These compounds are particularly suitable for use as additives for lubricant compositions, hydraulic fluids and machining fluids.