Lubricating oil compositions containing amine compounds having improved seal performance

Abstract

Provided is an internal combustion engine lubricating oil composition which comprises a major amount of an oil of lubricating viscosity; one or more oil soluble or oil dispersible organic acid anhydrides, said anhydride comprising at least one hydrocarbyl or hydrocarbylene moiety having from about 10 to about 400 carbon atoms; and an oil soluble or oil dispersible secondary hydrocarbylamine compound, a tertiary hydrocarbylamine compound, or combinations thereof. Also provided is a method for maintaining and/or increasing fresh oil TBN of a lubricating oil composition while at the same time improving seal performance in an internal combustion engine.

What is claimed is: 
     
         1 . An internal combustion engine lubricating oil composition which comprises
 (a) a major amount of an oil of lubricating viscosity;   (b) one or more oil soluble or oil dispersible organic acid anhydrides, said anhydride comprising at least one hydrocarbyl or hydrocarbylene moiety having from about 10 to about 400 carbon atoms; and   (c) an oil soluble or oil dispersible secondary hydrocarbylamine compound, a tertiary hydrocarbylamine compound, or combinations thereof,   wherein the tertiary hydrocarbylamine compound is a compound having the following formula (5):
   R 8 R 9 R 10 N  (Formula 5),
 
   wherein R 8 , R 9 , and R 10  are the same or different and each individually are selected from the group consisting of straight-chain or branched, saturated or unsaturated C 1 -C 40  hydrocarbyl group.   
     
     
         2 . The composition of  claim 1 , wherein the organic acid anhydride compound is a compound having the following Formula 1: 
       
         
           
           
               
               
           
         
         wherein each R 1 , R 2 , R 3 , and R 4 , when present, are independently a hydrogen radical, or a hydrocarbyl or hydrocarbylene radical, with at least one of R 1 , R 2 , R 3 , and R 4  being a hydrocarbyl or hydrocarbylene radical. 
       
     
     
         3 . The composition of  claim 2 , wherein the hydrocarbyl and hydrocarbylene radicals as described for R 1 , R 2 , R 3 , and R 4  can independently be an alkyl or alkylene radical having a number average molecular weight from about 350 to about 5000. 
     
     
         4 . The composition of  claim 1 , wherein the organic acid anhydride compound is a reaction product of polyisobutylene (PIB) and maleic anhydride. 
     
     
         5 . The composition of  claim 4 , wherein the reaction products of polyisobutylenes and maleic anhydride is represented by either Formula 2 or Formula 3: 
       
         
           
           
               
               
           
         
         wherein R 5  is a polyisobutylene (PIB) chain. 
       
     
     
         6 . The lubricating oil composition of  claim 1 , wherein [c] has a weight average molecular weight of from 100 to 1200. 
     
     
         7 . The lubricating oil composition of  claim 1 , wherein the [c] has a TBN value of from 20 to 500 mgKOH/g when tested according to ASTM D2896. 
     
     
         8 . The lubricating oil composition of  claim 1 , wherein the secondary hydrocarbylamine compound is a compound having the following formula (4):
   R 6 R 7 NH  (Formula 4),
   wherein R 6  and R 7  are the same or different and each individually are selected from the group consisting of straight-chain or branched, saturated or unsaturated C 1 -C 40  hydrocarbyl group.   
     
     
         9 . The lubricating oil composition of  claim 1 , wherein the secondary hydrocarbylamine is a hindered secondary hydrocarbylamine compound. 
     
     
         10 . A method for increasing fresh oil TBN of a lubricating oil composition while at the same time improving seal performance in an internal combustion engine comprising:
 (a) lubricating said engine with a lubricating oil according to  claim 1 , and   (b) operating said engine.   
     
     
         11 . A method of maintaining TBN of a lubricating oil composition while at the same time improving seal performance in an internal combustion engine comprising:
 (c) lubricating said engine with a lubricating oil according to  claim 1 , and   (d) operating said engine.   
     
     
         12 . The method of  claim 10  or  11 , wherein the seals are fluoroelastomer seals.