Lubricating oil containing alkyl phosphonic acid

Abstract

This disclosure describes a zinc-free lubricating oil composition. The composition includes a major amount of an oil of lubricating viscosity having a kinematic viscosity at 100° C. in a range of about 1.5 to about 35 mm2/s and an anti-wear mixture having one or more ashless dispersants and an alkyl phosphonic acid having a structure given bywherein R is a C3-C20 hydrocarbyl group. The initial pH of the anti-wear mixture is between 5-9.5 as measured by ASTM D664.

1 . A lubricating oil composition comprising:
 a major amount of an oil of lubricating viscosity having a kinematic viscosity at 100° C. in a range of about 1.5 to about 35 mm 2 /s; and   an anti-wear mixture comprising: one or more ashless dispersants and an alkyl phosphonic acid having a structure given by   
       
         
           
           
               
               
           
         
         wherein R is a C 3 -C 20  hydrocarbyl group; initial pH of the anti-wear mixture is between 5.0-9.5 as measured by ASTM D664; and wherein the lubricating oil composition is free of zinc. 
       
     
     
         2 . The lubricating oil composition of  claim 1 , wherein the one or more ashless dispersants include a hydrocarbyl succinimide. 
     
     
         3 . The lubricating oil composition of  claim 1 , wherein the one or more ashless dispersant include a borated hydrocarbyl succinimide. 
     
     
         4 . The lubricating oil composition of  claim 1 , wherein the volume resistivity is greater than 1×10 8  Ω·cm at 80° C. 
     
     
         5 . The lubricating oil composition of  claim 1 , wherein the lubricating oil composition is a hydraulic fluid, a slide way lubricant, automatic transmission fluid, continuously variable transmission fluid, battery electric vehicle, hybrid electric vehicle transmission fluid, or gear oil. 
     
     
         6 . The lubricating oil composition of  claim 1 , further comprising:
 a friction modifier, ashless anti-wear additive, antioxidant, metal deactivator, seal swell additive, foam inhibitor, or viscosity modifier.   
     
     
         7 . The lubricating oil composition of  claim 1 , wherein R is a linear alkyl group optionally containing an ether or thioether moiety. 
     
     
         8 . A lubricating oil composition comprising:
 a major amount of an oil of lubricating viscosity having a kinematic viscosity at 100° C. in a range of about 1.5 to about 35 mm 2 /s; and   an anti-wear mixture comprising: one or more polyisobutenyl succinimide dispersants and an alkyl phosphonic acid having a structure given by   
       
         
           
           
               
               
           
         
         wherein R is a C 3 -C 20  hydrocarbyl group; initial pH of the anti-wear mixture is between 5.0-9.5 as measured by ASTM D664; and wherein the lubricating oil composition is free of zinc. 
       
     
     
         9 . The lubricating oil composition of  claim 8 , wherein the one or more polyisobutenyl succinimide is borated. 
     
     
         10 . The lubricating oil composition of  claim 8 , wherein at least one of the one or more polyisobutenyl succinimide has a polyisobutylene group with a number average molecular weight of about 850 or greater. 
     
     
         11 . The lubricating oil composition of  claim 8 , wherein the volume resistivity is greater than 1×10 8  Ω·cm at 80° C. 
     
     
         12 . The lubricating oil composition of  claim 8 , wherein the lubricating oil composition is a hydraulic fluid, slide way lubricant, automatic transmission fluid, continuously variable transmission fluid, battery electric vehicle, hybrid electric vehicle transmission fluid, or gear oil. 
     
     
         13 . The lubricating oil composition of  claim 8 , further comprising:
 a friction modifier, ashless anti-wear additive, antioxidant, metal deactivator, seal swell additive, foam inhibitor, or viscosity modifier.   
     
     
         14 . The lubricating oil composition of  claim 8 , wherein R is a linear alkyl group optionally containing an ether or thioether moiety. 
     
     
         15 . A method of reducing wear of a transmission or gear comprising:
 lubricating the transmission or gear with a lubricating oil composition comprising:   a major amount of an oil of lubricating viscosity having a kinematic viscosity at 100° C. in a range of about 1.5 to about 35 mm 2 /s; and   an anti-wear mixture comprising: one or more ashless dispersants and an alkyl phosphonic acid of the following formula:   
       
         
           
           
               
               
           
         
         wherein R is a C 3 -C 20  hydrocarbyl group; 
         wherein the initial pH of the anti-wear mixture is between 5.0-9.5 when measured by the ASTM D664 method; and wherein the lubricating oil composition is free of zinc. 
       
     
     
         16 . The method of  claim 15 , wherein the one or more ashless dispersants include a hydrocarbyl succinimide. 
     
     
         17 . The method of  claim 15 , wherein the one or more ashless dispersants include a borated hydrocarbyl succinimide. 
     
     
         18 . The method of  claim 15 , wherein the volume resistivity is greater than 1×10 8  Ω·cm at 80° C. 
     
     
         19 . The method of  claim 15 , wherein the lubricating oil composition further comprises:
 a friction modifier, ashless anti-wear additive, antioxidant, metal deactivator, seal swell additive, foam inhibitor, or viscosity modifier.   
     
     
         20 . The method of  claim 15 , wherein R is a linear alkyl group optionally containing an ether or thioether moiety.