Lubricant Additive Packages for Improving Load-Carrying Capacity and Surface Fatigue Life

Abstract

The present invention provides a multifunctional lubricant additive package or composition for improving load-carrying capacity, pressure resistance, surface fatigue life, and other performance characteristics of a lubricant or base oil. The composition typically includes four components: (a) an alkyl or aryl neutral phosphate, (b) a long-chain organic partial ester, (c) an aryl or alkyl phosphite, and (d) a phenol compound. The present invention further provides a multifunctional lubricant having improved performance characteristics, which are obtained by mixing a lubricant with the above-described multifunctional lubricant additive package or composition.

1 . A multifunctional lubricant composition comprising at least one additive selected from the group consisting of:
 an aryl or alkyl neutral phosphate, a long-chain ester, an aryl or alkyl phosphite, a phenol compound, or any combinations thereof;   wherein the aryl of alkyl neutral phosphate has the formula:   
     
       
         
         
             
             
         
       
       wherein R 1 , R 2 , and R 3  are each independently C n H 2n+1  alkyl groups of an alkyl neutral phosphate or (C 6 H 5 C m H 2m+1 ) aryl groups 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; 
       wherein the long-chain ester has the general formula: 
     
     
       
         
         
             
             
         
       
       wherein R 4  and R 5  are each independenly a normal C i H 2i+1  alkyl groups, wherein i is an integer of about 7≦i≦15; 
       wherein the aryl or alkyl phosphite, has the following 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 groups, and j is an integer of about 1≦j≦20; and 
       wherein the phenol compound has the general formula: 
     
     
       
         
         
             
             
         
       
       wherein R 12 , R 12′ , R 12″ , and R 12′″  are each C p H 2p+1  alkyl groups, wherein 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 normal C o H 2o+1  alkyl group, and wherein o is an integer of about 1≦o≦20. 
     
   
   
       2 . The composition according to  claim 1 , wherein n is an integer of about 4≦n≦6 and m is an integer of about 1≦m≦5. 
   
   
       3 . The composition according to  claim 1 , wherein i is an integer of about 8≦i≦10. 
   
   
       4 . The composition according to  claim 1 , wherein j is an integer of about 4≦j≦8. 
   
   
       5 . The composition according to  claim 1 , wherein p is an integer of about 1≦p≦5, and o is an integer of about 2≦o≦10. 
   
   
       6 . The composition according to  claim 1 , wherein R 15  and R 16  are tertiary structures. 
   
   
       7 . The composition according to  claim 1 , wherein the aryl or alkyl neutral phosphate is tricresyl phosphate. 
   
   
       8 . The composition according to  claim 1 , wherein the aryl or alkyl neutral phosphate is present in an amount from about 0.1% to 5% by mole based on the total amount of lubricant. 
   
   
       9 . The composition according to  claim 1 , wherein the aryl or alkyl neutral phosphate is present in an amount from about 0.2% to 2% by mole based on the total amount of lubricant. 
   
   
       10 . The composition according to  claim 1 , wherein the long-chain ester is glycerol monooleate. 
   
   
       11 . The composition according to  claim 1 , wherein the long-chain ester is present in an amount from about 0.2% to 6% by mole based on the total amount of lubricant. 
   
   
       12 . The composition according to  claim 1 , wherein the long-chain ester is present in an amount from about 0.6% to 2% by mole based on the total amount of lubricant. 
   
   
       13 . The composition according to  claim 1 , wherein the aryl or alkyl phosphite is tris-(2,4-di-tertiary-butyl-phenyl)phosphite. 
   
   
       14 . The composition according to  claim 1 , wherein the alkyl or aryl phosphite is present in an amount from about 0.05% to 4.5% by mole based on the total amount of lubricant. 
   
   
       15 . The composition according to  claim 1 , wherein the alkyl or aryl phosphite is present in an amount of about 0.18% to 1.8% by mole based on the total about of lubricant. 
   
   
       16 . The composition according to  claim 1 , wherein the phenol compound is present in an amount of about 0.005% to 1% by mole based on the total amount of lubricant. 
   
   
       17 . The composition according to  claim 1 , wherein the phenol compound is present in an amount of about 0.02% to 0.3% by mole based on the total about of lubricant. 
   
   
       18 . The composition according to  claim 1 , wherein the phenol compound is Tetrakis-(methyline-3,5-ditert-butyl-4-hydroxy hydrocinnamate)methane. 
   
   
       19 . The composition according to  claim 1 , wherein the total concentration of the additives is about 10% or less by mole based on the total amount of lubricant. 
   
   
       20 . The composition according to  claim 1 , wherein the lubricant is selected from gear oil, bearing oil, sliding surface lubricating oil, chain lubricating oil, engine oil, and synthetic polyol ester, or any combinations thereof. 
   
   
       21 . A method of improving the performance characteristics of a lubricant, comprising the step of mixing a lubricant with a multifunctional lubricant additive composition comprising additives selected from the group consisting of:
 an aryl or alkyl neutral phosphate, a long-chain ester, an aryl or alkyl phosphite, a phenol compound, or any combinations thereof, wherein the aryl of alkyl neutral phosphate has the formula:   
     
       
         
         
             
             
         
       
       wherein R 1 , R 2 , and R 3  are each independently C n H 2n+1  alkyl groups of an alkyl neutral phosphate or (C 6 H 5 C m H 2m+1 ) aryl groups 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; 
       wherein the long-chain ester has the general formula: 
     
     
       
         
         
             
             
         
       
       wherein R 4  and R 5  are each independently a normal C i H 2i+1  alkyl group, wherein i is an integer of about 7≦i≦15; 
       wherein the aryl or alkyl phosphite, has the following 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, and j is an integer of about 1≦j≦20; and 
       wherein the phenol compound has the general formula: 
     
     
       
         
         
             
             
         
       
       wherein R 12 , R 12′ , R 12″ , and R 12′″  are each independently a normal C p H 2p+1  alkyl group, wherein p is an integer of about 1≦p≦12; wherein R 13 , R 13′ , R 13″ , and R 13′″  are each a phenol group represented by the formula: 
     
     
       
         
         
             
             
         
       
       wherein R 14 , R 15 , and R 16  are each a C o H 2o+1  alkyl group, and wherein o is an integer of about 1≦o≦20. 
     
   
   
       22 . The method of  claim 21 , wherein n is an integer of about 4≦n≦6 and m is an integer of about 1≦m≦5. 
   
   
       23 . The method of  claim 21 , wherein i is an integer of about 8≦i≦10. 
   
   
       24 . The method of  claim 21 , wherein j is an integer of about 4≦j≦8. 
   
   
       25 . The method of  claim 21 , wherein p is an integer of about 1≦p≦5, and o is an integer of about 2≦o≦10. 
   
   
       26 . The method of  claim 21 , wherein R 15  and R 16  are tertiary structures. 
   
   
       27 . The method of  claim 21 , wherein the aryl or alkyl neutral phosphate is tricresyl phosphate. 
   
   
       28 . The method of to  claim 21 , wherein the aryl or alkyl neutral phosphate is present in an amount from about 0.1% to 5% by mole based on the total amount of lubricant. 
   
   
       29 . The method of  claim 21 , wherein the aryl or alkyl neutral phosphate is present in an amount from about 0.2% to 2% by mole based on the total amount of lubricant. 
   
   
       30 . The method of  claim 21 , wherein the long-chain ester is glycerol monooleate. 
   
   
       31 . The method of  claim 21 , wherein the long-chain ester is present in an amount from about 0.2% to 6% by mole based on the total amount of lubricant. 
   
   
       32 . The method of  claim 21 , wherein the long-chain ester is present in an amount from about 0.6% to 2% by mole based on the total amount of lubricant. 
   
   
       33 . The method of  claim 21 , wherein the aryl or alkyl phosphite is tris-(2,4-di-tertiary-butyl-phenyl)phosphite. 
   
   
       34 . The method of  claim 21 , wherein the alkyl or aryl phosphite is present in an amount from about 0.05% to 4.5% by mole based on the total amount of lubricant. 
   
   
       35 . The method of  claim 21 , wherein the alkyl or aryl phosphite is present in an amount of about 0.18% to 1.8% by mole based on the total about of lubricant. 
   
   
       36 . The method of  claim 21 , wherein the phenol compound is present in an amount of about 0.005% to 1% by mole based on the total amount of lubricant. 
   
   
       37 . The method of  claim 21 , wherein the phenol compound is present in an amount of about 0.02% to 0.3% by mole based on the total about of lubricant. 
   
   
       38 . The method of  claim 21 , wherein the phenol compound is tetrakis-(methyline-3,5-ditert-butyl-4-hydroxy hydrocinnamate)methane. 
   
   
       39 . The method of  claim 21 , wherein the total concentration of the additives is about 10% or less by mole based on the total amount of lubricant. 
   
   
       40 . The method of  claim 21 , wherein the lubricant is selected from gear oil, bearing oil, sliding surface lubricating oil, chain lubricating oil, engine oil, and synthetic polyol ester. 
   
   
       41 . A multifunctional lubricant comprising:
 a base lubricant; and   at least one additive selected from the group consisting of: an aryl or alkyl neutral phosphate, a long-chain ester, an aryl or alkyl phosphite, a phenol compound, or any combinations thereof;   wherein the aryl of alkyl neutral phosphate has the formula:   
     
       
         
         
             
             
         
       
       wherein R 1 , R 2 , and R 3  are each independently C n H 2n+1  alkyl groups of an alkyl neutral phosphate or (C 6 H 5 C m H 2m+1 ) aryl groups 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; 
       wherein the long-chain ester has the general formula: 
     
     
       
         
         
             
             
         
       
       wherein R 4  and R 5  are each independenly a normal C i H 2i+1  alkyl group, wherein i is an integer of about 7≦i≦15; 
       wherein the aryl or alkyl phosphite, has the following 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, and j is an integer of about 1≦j≦20; and 
       wherein the phenol compound has the general formula: 
     
     
       
         
         
             
             
         
       
       wherein R 12 , R 12′ , R 12 ″, and R 12′″  are each C p H 2p+1  alkyl groups, wherein 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 normal C o H 2o+1  alkyl group, and wherein o is an integer of about 1≦o≦20. 
     
   
   
       42 . The multifunctional lubricant composition of  claim 1 , wherein when the multifunctional lubricant composition is added to a base lubricant to form an improved lubricant, the improved lubricant has a scuffing performance of at least about 1.43 times greater than the scuffing performance of the base lubricant. 
   
   
       43 . The multifunctional lubricant composition of  claim 1 , wherein when the multifunctional lubricant composition is added to a base lubricant to form an improved lubricant, the improved lubricant has a surface fatigue life performance of at least about 2.9 times greater than the surface fatigue life performance of the base lubricant. 
   
   
       44 . The multifunctional lubricant composition of  claim 1 , wherein the ratio of the amount by mole based on the total amount of lubricant of phenol compound of additive (d) to that of the aryl or alkyl phosphite of additive (c) is about 1:10. 
   
   
       45 . The multifunctional lubricant composition of  claim 1 , wherein the ratio of the amount by mole based on the total amount of lubricant of the an aryl or alkyl neutral phosphate, that of a long-chain ester, and that of an aryl or alkyl phosphate is about 0.5:1.0:0.45.