Oil soluble polyalkylene glycol lubricant compositions

Abstract

A lubricant composition comprising at least 90 wt % of at least one oil soluble polyalkylene glycol (OSP), wherein the OSP comprises at least 40 wt % units derived from butylene oxide and at least 40 wt % units derived from propylene oxide, initiated by one or more initiators selected from monols, diols, and polyols; and at least 0.05 wt % of at least one anti-wear additive; wherein the lubricant composition exhibits a four ball anti-wear of less than or equal to 0.35 mm and an air release value at 50° C. of less than or equal to 1 minute is provided.

1 . A lubricant composition comprising
 at least 90 wt % of at least one oil soluble polyalkylene glycol (OSP), wherein the OSP comprises at least 40 wt % units derived from butylene oxide and at least 40 wt % units derived from propylene oxide, initiated by one or more initiators selected from monols, diols and polyols; and   at least 0.05 wt % of at least one anti-wear additive;   wherein the lubricant composition exhibits a four ball anti-wear of less than or equal to 0.35 mm and an air release value at 50° C. of less than or equal to 1 minute.   
     
     
         2 . The lubricant composition according to  claim 1 , wherein each of the at least one OSP exhibits an aniline point of less than −20° C. 
     
     
         3 . The lubricant composition according to  claim 1 , wherein each of the at least one OSPs has a kinematic viscosity at 40° C. between 15 and 250 cSt. 
     
     
         4 . The lubricant composition according to  claim 1 , wherein each of the at least one anti-wear additives is present in an amount from 0.1 to 0.25 wt %. 
     
     
         5 . The lubricant composition according to  claim 1 , wherein the anti-wear additives are selected from the group consisting of zinc dialkyldithiophosphates, amine phosphates, dithiocarbamates, alkylphosphate esters, ashless dithiocarbamates, ashless ditiophosphate, combinations thereof, and blends thereof. 
     
     
         6 . The lubricant composition according to  claim 1 , wherein each of the at least one OSP exhibits an aniline point of less than —25° C. 
     
     
         7 . The lubricant composition according to  claim 1 , further comprising one or more additives selected from the group consisting of extreme pressure additives, yellow metal passivators, and anti-oxidants. 
     
     
         8 . The lubricant composition according to  claim 1 , wherein the lubricant composition further exhibits an air release value at 75° C. of less than or equal to 1 minute. 
     
     
         9 . The lubricant composition according to  claim 1 , wherein the lubricant composition exhibits a four ball anti-wear of less than or equal to 0.32 mm. 
     
     
         10 . A lubricant composition comprising
 at least 90 wt % of at least one oil soluble polyalkylene glycol (OSP), wherein the OSP is a polymer selected from the group consisting of copolymers comprising units derived from propylene oxide and butylene oxide, polybutylene oxide homopolymer, and combinations thereof and wherein the OSP exhibits a kinematic viscosity at 40° C. of greater than or equal to 100 cSt; and   from 0.25 to 2 wt % of at least one extreme pressure additive;   wherein the lubricant composition exhibits a four ball EP weld load of at least 160 kg and an air release value at 75° C. of less than or equal to 3 minutes.   
     
     
         11 . The lubricant composition according to  claim 10 , further comprising an extreme pressure additive selected from the group consisting of ashless dithiophosphates, triaryl phosphothionates, alkyl diphenylphosphites, amine phosphates, dithiophosphates, triaryl phosphothionates, blends thereof and combinations thereof. 
     
     
         12 . A hydraulic fluid comprising the lubricant composition according to  claim 1 . 
     
     
         13 . A hydraulic fluid comprising the lubricant composition according to  claim 10 .