Lubricating compositions and concentrates containing an antiwear amount of a thiadiazole

Abstract

This invention relates to lubricating compositions comprising a major amount of an oil of lubricating viscosity and at least about 0.4% by weight of at least one amine free thiadiazole, wherein the lubricating composition is free of organic polysulfides and contains less than about 2% by weight of at least one dispersant. The invention also relates to concentrates and methods of using the lubricating compositions to control micro pitting. The lubricants provide improved performance for both macro and micro pitting, especially micro pitting.

1 . A lubricating composition comprising a major amount of an oil of lubricating viscosity and at least about 0.4% by weight of at least one amine free thiadiazole, wherein the lubricating composition is free of organic polysulfides and contains less than about 2% by weight of at least one dispersant.  
     
     
         2 . The composition of  claim 1  wherein the mercaptothiadiazole is at least one hydrocarbyl or bis-hydrocarbyl substituted thio or di thiothiadiazole.  
     
     
         3 . The composition of  claim 1  further comprising less that about 1.5% by weight of at least one dispersant.  
     
     
         4 . The composition of  claim 1  further comprising at least one anti-foam agent.  
     
     
         5 . The composition of  claim 1  further comprising at least one imidazoline or reaction product of at least one fatty carboxylic acid and at least one polyamine.  
     
     
         6 . The composition of  claim 1  further comprising at least one phosphorus antiwear agent.  
     
     
         7 . A lubricating composition comprising a major amount of an oil of lubricating viscosity and at least about 0.4% by weight of an amine free thiadiazole, at least one phosphorus antiwear agent, less than about 2% by weight of at least one dispersant, wherein the lubricating composition is free of polysulfide compounds.  
     
     
         8 . The composition of  claim 7  further comprising at least one imidazoline or reaction product of at least one fatty carboxylic acid and at least one polyamine.  
     
     
         9 . The composition of  claim 7  further comprising at least one antifoam agent.  
     
     
         10 . An industrial gear oil composition comprising a major amount of an oil of lubricating viscosity and at least about 0.4% of at least one amine-free thiadiazole and at least one phosphorus antiwear agent, wherein the lubricant is free of polysulfide compounds.  
     
     
         11 . The composition of  claim 10  wherein the composition further comprises less that about 2% by weight of at least one dispersant.  
     
     
         12 . The composition of  claim 10  wherein the composition further comprises at least one imidazoline or reaction product of at least one fatty carboxylic acid and at least one polyamine.  
     
     
         13 . An industrial gear oil composition comprising a major amount of an oil of lubricating viscosity and at least about 0.4% by weight of at least one amine-free thiadiazole, less than about 2% by weight of at least one dispersant, and at least one phosphorus antiwear agent, wherein the industrial gear oil composition is free of polysulfide compounds.  
     
     
         14 . The composition of  claim 13  further comprising at least one imidazoline or reaction product of at least one fatty carboxylic acid and at least one polyamine.  
     
     
         15 . An manual transmission composition comprising a major amount of an oil of lubricating viscosity and at least about 0.4% of at least one amine-free thiadiazole, wherein the lubricant is free of organic polysulfides and contains less than about 2% by weight of at least one dispersant.  
     
     
         16 . The composition of  claim 15  further comprising at least one phosphorus antiwear agent.  
     
     
         17 . The composition of  claim 15  further comprising at least one imidazoline or reaction product of at least one fatty carboxylic acid and at least one polyamine.  
     
     
         18 . The composition of  claim 15  further comprising at least one overbased metal salt of an acidic organic compound.  
     
     
         19 . The composition of  claim 15  further comprising at least one antioxidant.  
     
     
         20 . The composition of  claim 15  further comprising at least one antifoam agent.  
     
     
         21 . A manual transmission composition comprising a major amount of an oil of lubricating viscosity and at least 0.4% by weight of at least one amine free thiadiazole, at least one phosphorus antiwear agent, less than about 2% by weight of at least one dispersant, wherein the manual transmission composition is free of organic polysulfides.  
     
     
         22 . The composition of  claim 21  further comprising at least one antifoam agent or at least one imidazoline or reaction product of at least one fatty carboxylic acid and at least one polyamine.