Grease composition for use in constant velocity joints comprising at least one tri-nuclear molybdenum compound

Abstract

To solve the problem to provide for a new grease composition giving low wear and low friction primarily to constant velocity joints, a grease composition is suggested comprising a) a base oil composition; and b) 0.25% by weight to 5% by weight of at least one tri-nuclear molybdenum corn pound of the formula Mo 3 SkL n Q z wherein L are independently selected ligands having organo groups with a sufficient number of carbon atoms to render the compound soluble or dispersible in the oil, n is from 1 to 4, k varies from 4 though 7, Q is selected from the group of neutral electron donating compounds such as amines, alcohols, phosphines, and ethers, and z ranges from 0 to 5 and includes non-stoichiometric values.

1 . A grease composition for use in constant velocity joints comprising
 a) a base oil composition; and   b) 0.25% by weight to 5% by weight of at least one tri-nuclear molybdenum compound of the formula
   Mo 3 S k L n Q z , 
   wherein L are independently selected ligands having organo groups with a sufficient number of carbon atoms to render the compound soluble or dispersible in the oil, n is from 1 to 4, k varies from 4 though 7, Q is selected from the group of neutral electron donating compounds consisting of amines, alcohols, phosphines, and ethers, and z ranges from 0 to 5 and includes non-stoichiometric values.   
   
   
       2 . A grease composition according to  claim 1 , further comprising at least one zinc compound additive. 
   
   
       3 . A grease composition according to  claim 2 , comprising at least one zinc compound additive in an amount of between 0.1% by weight to 2.5% by weight, referred to the total amount of the composition. 
   
   
       4 . A grease composition according to  claim 3  where the zinc compound is at least one selected from the group consisting of zinc dithiophosphates, zinc dithiocarbamates, zinc oxide, and zinc sulfide. 
   
   
       5 . A grease composition according to  claim 1 , further comprising a thickener selected from the group consisting of lithium soaps, calcium soaps, lithium-complex soaps, calcium-complex soaps, urea-derivative type thickener, and mixtures thereof. 
   
   
       6 . A grease composition according to  claim 1 , characterised in that the base oil composition comprises at least one of poly-[alpha]-olefins, naphthenic oils, paraffinic oils, and synthetic organic esters. 
   
   
       7 . A grease composition according to  claim 1 , further comprising an additive package selected from the group of agents consisting of anti-oxidation agents, corrosion inhibitors, anti-wear agents, friction modifiers, and/or extreme pressure agents, and mixtures thereof. 
   
   
       8 . A grease composition according to  claim 1 , comprising 55% by weight to 97.5% by weight of the base oil composition, 0.3% by weight to 3% by weight of at least one tri-nuclear molybdenum compound, 0.1% by weight to 1.5% by weight of at least one zinc compound additive, and between 2% and 25% by weight of at least one thickener in each case referred to the total amount of the grease composition. 
   
   
       9 . A grease composition according to  claim 1 , characterised in that the sliding friction coefficient of the grease composition is not more than 0.1.