Additive composition for transmission oil containing hexagonal boron nitride and polymethacrylate or dispersant olefin co-polymer

Abstract

Disclosed are additive compositions for transmission oils comprising an oil dispersion of a hexagonal boron nitride and a polymethacrylate, a dispersant polymethacrylate or a dispersant olefin copolymer viscosity index improver, as well as lubricating oil compositions containing the same.

1 . A composition, comprising:
 a transmission oil additive containing   a) an oil dispersion of hexagonal boron nitride having a particle size distribution wherein 90% or greater of the particles are less than about 0.5 microns; and   b) a viscosity index improver selected from the group consisting of
 i) a non-dispersant polymethacrylate, 
 ii) a dispersant polymethacrylate, and 
 iii) a dispersant olefin copolymer. 
   wherein the weight ratio of the oil dispersion of hexagonal boron nitride to the viscosity index improver is in the range of about 99:1 to about 1:99.   
     
     
         2 . The composition of  claim 1 , wherein the weight ratio of the oil dispersion of hexagonal boron nitride to the viscosity index improver is in the range of about 5:95 to about 95:5. 
     
     
         3 . The composition of  claim 1 , wherein the oil dispersion of hexagonal boron nitride contains an oil of lubricating viscosity and about 1 to about 50 wt % of hexagonal boron nitride solids, based on the total weight of the oil dispersion. 
     
     
         4 . The composition of  claim 3 , wherein the oil dispersion of hexagonal boron nitride further contains a surfactant as a stabilizer. 
     
     
         5 . The composition of  claim 1 , wherein the oil dispersion of hexagonal boron nitride is present in the transmission oil additive in the range of about 10 to about 90 wt %, based on the total weight of the transmission oil additive. 
     
     
         6 . The composition of  claim 1 , wherein the non-dispersant polymethacrylate contains short chain, intermediate chain or long chain hydrocarbon side chains. 
     
     
         7 . The composition of  claim 1 , wherein the dispersant polymethacrylate contains short chain, intermediate chain or long chain dispersant hydrocarbon side chains. 
     
     
         8 . The composition of  claim 1 , wherein the dispersant olefin copolymer is a dispersant ethylene-propylene olefin copolymer. 
     
     
         9 . The composition of  claim 1 , wherein the transmission oil additive further comprises an oil dispersion of hydrated alkali metal borate. 
     
     
         10 . The composition of  claim 9 , wherein the alkali metal in the hydrated alkali metal borate is sodium or potassium. 
     
     
         11 . The composition of  claim 10 , wherein the alkali metal is potassium. 
     
     
         12 . The composition of  claim 9 , wherein the hydrated alkali metal borate is hydrated potassium triborate. 
     
     
         13 . The composition of  claim 9 , wherein the oil dispersion of hydrated alkali metal borate contains a hydrated alkali metal borate, a dispersant, and an oil of lubricating viscosity. 
     
     
         14 . The composition of  claim 13 , wherein the oil dispersion of hydrated alkali metal borate contains about 10 to about 75 wt % of the hydrated alkali metal borate, based on the total weight of the oil dispersion. 
     
     
         15 . The composition of  claim 14 , wherein the oil dispersion of hydrated alkali metal borate contains about 2 to about 40 wt % of the dispersant, based on the total weight of the oil dispersion. 
     
     
         16 . The composition of  claim 15 , wherein the oil dispersion of hydrated alkali metal borate further contains a detergent. 
     
     
         17 . The composition of  claim 16 , wherein the oil dispersion of hydrated alkali metal borate contains about 0.2 to about 10 wt % of the detergent, based on the total weight of the oil dispersion. 
     
     
         18 . The composition of  claim 9 , wherein the oil dispersion of hydrated alkali metal borate is present in the transmission oil additive in the range of about 10 to about 90 wt %, based on the total weight of the transmission oil additive. 
     
     
         19 . A lubricating oil composition comprising a major amount of a transmission oil of lubricating viscosity and an effective synchronizer sticking reducing amount of a transmission oil additive containing:
 a) an oil dispersion of hexagonal boron nitride having a particle size distribution wherein 90% or greater of the particles are less than about 0.5 microns; and   b) a viscosity index improver selected from the group consisting of
 (i) a non-dispersant polymethacrylate, 
 (ii) a dispersant polymethacrylate, and 
 iii) a dispersant olefin copolymer, 
   wherein the weight ratio of the oil dispersion of hexagonal boron nitride to the viscosity index improver is in the range of 99:1 to about 1:99.   
     
     
         20 . The composition of  claim 19 , wherein the weight ratio of the oil dispersion of hexagonal boron nitride to the viscosity index improver is in the range of about 5:95 to about 95:5. 
     
     
         21 . The composition of  claim 19 , wherein the lubricating oil composition contains about 1 to about 20 wt % of the transmission oil additive, based on the total weight of the lubricating oil composition. 
     
     
         22 . The composition of  claim 19 , wherein the transmission oil of lubricating viscosity is a manual transmission gear oil.