Multifunctional Lubricant Additive Package for a Rough Mechanical Component Surface

Abstract

The present invention provides a multifunctional lubricant additive or composition for improving load-carrying capacity, scuffing (scoring) resistance, and other performance characteristics of a lubricant. The composition includes a friction modifier, an antiwear additive, an extreme pressure additive, and a surface fatigue life modifier. The present invention further provides a method for improving the performance characteristics of a lubricant, which includes a step of mixing a lubricant base oil or fully formulated lubricant with the above-described multifunctional lubricant additive composition.

1 . A multifunctional lubricant additive package for improving the performance characteristics of a lubricant, said composition comprising:
 a friction modifier comprising a long-chain ester represented by the formula:   
     
       
         
         
             
             
         
       
       wherein R 1  and R 2  are each independently a normal C i H 2i+1  alkyl group, and wherein i is an integer of about 7≦i≦15. 
     
   
   
       2 . A composition according to  claim 1 , wherein i is about 8≦i≦10. 
   
   
       3 . A composition according to  claim 1 , further comprising an antiwear additive comprising an alkyl neutral phosphate or an aryl neutral phosphate represented by the formula: 
     
       
         
         
             
             
         
       
       wherein R 3 , R 4 , and R 5  are each independently a C n H 2n+1  alkyl group of an alkyl neutral phosphate or a C 6 H 5 C m H 2m+1  aryl group of an aryl neutral phosphate, wherein n is an integer of about 2≦n≦10 and wherein m is an integer of about 0≦m≦8. 
     
   
   
       4 . A composition according to  claim 3 , wherein n is about 4≦n≦6. 
   
   
       5 . A composition according to  claim 3 , wherein m is about 1≦m≦5. 
   
   
       6 . A composition according to  claim 3 , further comprising an extreme pressure additive consisting of a combination of (a) at least one of an alkyl phosphite and an aryl phosphite, and (b) a phenol compound, wherein the alkyl or aryl phosphite is represented by the formula: 
     
       
         
         
             
             
         
       
       wherein R 6 , R 7 , R 8 , R 9 , R 10 , and R 11  are each independently C j H 2j+1  alkyl groups exhibiting tertiary structures, where j is an integer of about 1≦j≦20, wherein the phenol compound is represented by the formula: 
     
     
       
         
         
             
             
         
       
       wherein R 12 , R 12′ , R 12″ , and R 12′″  are each independently C p H 2p+1  alkyl groups and p is an integer of about 1≦p≦12; wherein R 13 , R 13′ , R 13″ , and R 13′″  are each independently a phenol group represented by the formula: 
     
     
       
         
         
             
             
         
       
       wherein R 14 , R 15 , and R 16  are each independently a C o H 2o+1  alkyl group and o is an integer of about 1≦o≦20, wherein R 15  and R 16  are tertiary structures. 
     
   
   
       7 . A composition according to  claim 6 , wherein j is about 4≦j≦8. 
   
   
       8 . A composition according to  claim 6 , further comprising a surface fatigue life modifier comprising an alkylthiocarbamoyl group represented by the formula: 
     
       
         
         
             
             
         
       
       wherein R 17 , R 18 , R 19 , and R 20  are each independently a C k H 2k+1  alkyl group and k is an integer of about 1≦k≦30, wherein R 17 , R 18 , R 19 , and R 20  optionally form a ring structure as combined together with the nitrogen atom to which they are bonded, where (A) is a chain of sulfur atoms, S n , or represented by the formula:
   S—(CH 2 ) m —S 
 
     
     and wherein n and m are integers of about 1≦n≦10 and about 1≦m≦6. 
   
   
       9 . The composition according to  claim 3 , wherein n of the antiwear additive is an integer of about 4≦n≦6 and m is an integer of about 1≦m≦5. 
   
   
       10 . The composition according to  claim 6 , wherein j of the extreme pressure additive is an integer of about 4≦j≦8, p is an integer of about 1≦p≦5, and o is an integer of about 2≦o≦10. 
   
   
       11 . The composition according to  claim 1 , wherein the friction modifier is glycerol monooleate. 
   
   
       12 . The composition according to  claim 1 , wherein the friction modifier is present in an amount from about 0.2% to 6% by mole based on the total amount of lubricant. 
   
   
       13 . The composition according to  claim 1 , wherein the friction modifier is present in an amount from about 0.6% to 2% by mole based on the total amount of lubricant. 
   
   
       14 . The composition according to  claim 3 , wherein the antiwear additive is tricresyl phosphate. 
   
   
       15 . The composition according to  claim 3 , wherein the antiwear additive is present in an amount from about 0.1% to 5% by mole based on the total amount of lubricant. 
   
   
       16 . The composition according to  claim 3 , wherein the antiwear additive is present in an amount from about 0.2% to 2% by mole based on the total amount of lubricant. 
   
   
       17 . The composition according to  claim 6 , wherein the extreme pressure additive compound (III) is tris-(2,4-di-tertiary-butyl-phenyl) phosphite. 
   
   
       18 . The composition according to  claim 6 , wherein the extreme pressure additive compound (III) is present in an amount from about 0.05% to 4.5% by mole based on the total about of lubricant. 
   
   
       19 . The composition according to  claim 6 , wherein the extreme pressure additive compound (III) is present in an amount from about 0.18% to 1.8% by mole based on the total about of lubricant. 
   
   
       20 . The composition according to  claim 6 , wherein the extreme pressure additive compound (IV) is present in an amount from about 0.005% to 1% by mole based on the total about of lubricant. 
   
   
       21 . The composition according to  claim 6 , wherein the extreme pressure additive compound (IV) is present in an amount from about 0.02% to 0.3% by mole based on the total about of lubricant. 
   
   
       22 . The composition according to  claim 6 , wherein the extreme pressure additive compound (IV) is tetrakis-(methylene-3,5-ditert-butyl-4-hydroxy hydrocinnamate) methane. 
   
   
       23 . The composition according to  claim 8 , wherein the surface fatigue life modifier is present in an amount from about 0.1% to 6% by mole based on the total amount of lubricant. 
   
   
       24 . The composition according to  claim 8 , wherein the surface fatigue life modifier is present in an amount from about 0.1% to 3% by mole based on the total amount of lubricant. 
   
   
       25 . A multifunctional lubricant composition for improving the performance characteristics of a lubricant, said composition comprising:
 a base stock;   a friction modifier comprising a long-chain ester represented by the formula:   
     
       
         
         
             
             
         
       
        wherein R 1  and R 2  are each independently a normal C i H 2i+1  alkyl group, and wherein i is an integer of about 7≦i≦15; 
       an antiwear additive comprising an alkyl neutral phosphate or an aryl neutral phosphate represented by the formula: 
     
     
       
         
         
             
             
         
       
       wherein R 3 , R 4 , and R 5  are each independently a C n H 2n+1  alkyl group of an alkyl neutral phosphate or a C 6 H 5 C m H 2m+1  aryl group of an aryl neutral phosphate, wherein n is an integer of about 2≦n≦10, and wherein m is an integer of about 0≦m≦8; 
       an extreme pressure additive consisting of a combination of (a) at least one of an alkyl phosphate and an aryl phosphate, and (b) a phenol compound, wherein the alkyl or aryl phosphite is represented by the formula: 
     
     
       
         
         
             
             
         
       
       wherein R 6 , R 7 , R 8 , R 9 , R 10 , and R 11  are each independently a C j H 2j+1  alkyl group exhibiting tertiary structures, where j is an integer of about 1≦j≦20, wherein the phenol compound is represented by the formula: 
     
     
       
         
         
             
             
         
       
       wherein R 12 , R 12′ , R 12″ , and R 12′″  are each independently a C p H 2p+1  alkyl group, and p is an integer of about 1≦p≦12; wherein R 13 , R 13′ , R 13″ , and R 13′″  are each independently a phenol group represented by the formula: 
     
     
       
         
         
             
             
         
       
       wherein R 14 , R 15 , and R 16  are each independently a C o H 2o+1  alkyl group and o is an integer of about 1≦o≦20, wherein R 15  and R 16  are tertiary structures; 
       a surface fatigue life modifier comprising an alkyl thiocarbamoyl group represented by the formula: 
     
     
       
         
         
             
             
         
       
       wherein R 17 , R 18 , R 19 , and R 20  are each independently a C k H 2k+1  alkyl group and k is an integer of about 1≦k≦30, wherein R 17 , R 18 , R 19 , and R 20  optionally form a ring structure as combined together with the nitrogen atom to which they are bonded, where (A) is a chain of sulfur atoms, S n , or represented by the formula:
   S—(CH 2 ) m —S 
 
     
     and wherein n and m are integers of about 1≦n≦10 and about 1≦m≦6. 
   
   
       26 . The composition according to  claim 25 , wherein the antiwear additive, extreme pressure additive, friction modifier, and surface life fatigue modifier are present in an amount from about 10% or less by mole based on the total amount of lubricant, wherein the ratio of the friction modifier:antiwear additive:extreme pressure additive:surface fatigue life modifier is about 2:1:1:0.5.