| abstract |
A lubricating composition comprising a base oil, one or more organomolibdenose compounds selected from the group consisting of sulfurized oxytolibdene dithiocarbamates represented by the formula (1) in which R1 to R4 are each a hydrocarbyl group, X1 is an atom of oxygen or sulfur and the atomic ratio of oxygen to sulfur is 1: 3 to 3: 1; and sulfurized oxyolibdene dithiophosphates represented by a formula (2) in which R5 to R8 are each a hydrocarbyl group and X2 is an oxygen or sulfur atom and the atomic ratio of oxygen to sulfur is 1: 3 to 3: 1; and one or more organozinc compounds selected from the group consisting of zinc dithiophosphates represented by the formula (3) in which a is 0 or 1/3 and R9 to R10 are each a hydrocarbyl group; and zinc dithiocarbamates represented by the formula (4) in which R11 and R12 are each a hydrocarbyl group; and cleaning agents selected from sulphonates, phenates and carboxylates of neutral or highly basic alkaline earth metals; characterized in that said composition has a total alkali metal content, including metallic sodium, below 100 ppm and in which the base oil is a base oil for lubricating oils. |