Lubricants containing ashless antiwear-dispersant additive having viscosity index improver credit

Abstract

A graft copolymer is disclosed. The copolymer is prepared by the interpolymerization of a mixture of monomers comprising ethylene, a C 3 to C 12 alpha monoolefin, and a polyene being a member selected from the group consisting of non-conjugated dienes and trienes. Grafted to the copolymer is a 2-mercapto-1,3,4-thiadiazole moiety. Lubricating oil additives and lubricating oils comprising the graft copolymer are also disclosed.

What is claimed is:  
     
       1. A graft copolymer comprising: 
       a copolymer prepared by the interpolymerization of a mixture of monomers comprising:  
       ethylene,  
       a C 3 -C 12  alpha monoolefin, and a polyene being a member selected from the group consisting of non-conjugated dienes and trienes;  
       having grafted thereon:  
       a 2-mercapto-1,3,4-thiadiazole moiety.  
     
     
       2. The graft copolymer of claim  1  wherein the C 3 -C 12  alpha monoolefin is propylene. 
     
     
       3. The graft copolymer of claim  1  wherein the polyene is a member selected from the group consisting of 1,4-hexadiene; 1,5-hexadiene; 1,4-pentadiene, 2-methyl-1,4-pentadiene; 3-methyl-1,4-hexadiene; 4-methyl-1,3-hexadiene; 1,7-octadiene; 1,9-decadiene; exodicyclopentadiene; endodicyclopentadiene; 5-propenylnorbornene; 5-(buten-2-yl)norbornene; 5-(2-methylbutene-{2′}-yl)norbornene; 5-methyl-6-propenylnorbornene; 5-methylene-2-norbornene; 5-ethylidene-2-norbornene; 5-isopropylidene-2-norbornene; vinylnorbornene; cyclohexenylnorbornene; methylnorbornadiene; ethylnorbornadiene; propylnorbornadiene; 1,5-cyclooctadiene; 1,4-cyclooctadiene; 1-isopropylidene-3a,4,7,7a-tetrahydroindene; 1-isopropyl idenedicyclopentadiene; dehydroisodicyclopentadiene; and 2-(2-methylene-4-methyl-3-pentenyl){2.2.1}bicyclo-5-heptene. 
     
     
       4. The graft copolymer of claim  1  wherein the 2-mercapto-1,3,4-thiadiazole moiety is derived from a compound having the structure                    
       wherein R 1  is hydrogen, alkyl, alkenyl, aryl, alkaryl, aralkyl, or 2-hydroxyalkyl; 
       X is sulfur;  
       Y is 0 or 1; and  
       R 2  is hydrogen or                    
     
     
       5. The graft copolymer of claim  4  wherein R 1  is hydrogen and Y is 0. 
     
     
       6. The graft copolymer of claim  5  wherein R 2  is hydrogen. 
     
     
       7. The graft copolymer of claim  4  wherein R 1  is the reacted moiety after reaction of the polyene in at least one fatty acid or fatty acid ester. 
     
     
       8. The graft copolymer of claim  7  wherein the fatty acid or fatty acid ester is a member selected from the group consisting of oleic acid, linoleic acid, methyl oleate, butyl oleate, butyl tallate, methyl tallate, octyl tallate, glyceryl monooleate, glyceryl monotallate, and pentaerythritol trioleate. 
     
     
       9. The graft copolymer of claim  1  having the structure                    
       where n is an integer in the range of about 1 to about 10. 
     
     
       10. A lubricant additive comprising a graft copolymer comprising: 
       a copolymer prepared by the interpolymerization of a mixture of monomers comprising:  
       ethylene,  
       a C 3 -C 12  alpha monoolefin, and a polyene being a member selected from the group consisting of non-conjugated dienes and trienes;  
       having grafted thereon:  
       a 2-mercapto-1,3,4-thiadiazole moiety.  
     
     
       11. The additive of claim  10  wherein the lubricant is a lubricating oil. 
     
     
       12. The additive of claim  10  wherein the C 3 -C 12  alpha monoolefin is propylene. 
     
     
       13. The additive of claim  10  wherein the polyene is a member selected from the group consisting of 1,4-hexadiene; 1,5-hexadiene; 1,4-pentadiene, 2-methyl-1,4-pentadiene; 3-methyl-1,4-hexadiene; 4-methyl-1,3-hexadiene; 1,7-octadiene; 1,9-decadiene; exodicyclopentadiene; endodicyclopentadiene; 5-propenylnorbornene; 5-(buten-2-yl)norbornene; 5-(2-methylbutene-{2′}-yl)norbornene; 5-methyl-6-propenylnorbornene; 5-methylene-2-norbornene; 5-ethylidene-2-norbornene; 5-isopropylidene-2-norbornene; vinylnorbornene; cyclohexenylnorbornene; methylnorbornadiene; ethylnorbornadiene; propylnorbornadiene; 1,5-cyclooctadiene; 1,4-cyclooctadiene; 1-isopropylidene-3a,4,7,7a-tetrahydroindene; 1-isopropylidenedicyclopentadiene; dehydroisodicyclopentadiene; and 2-(2-methylene-4-methyl-3-pentenyl){2.2.1}bicyclo-5-heptene. 
     
     
       14. The additive of claim  10  wherein the 2-mercapto-1,3,4-thiadiazole moiety is derived from a compound having the structure                    
       wherein R 1  is hydrogen, alkyl, alkenyl, aryl, alkaryl, aralkyl, or 2-hydroxyalkyl; 
       X is sulfur;  
       Y is 0 or 1; and  
       R 2  is hydrogen or                    
     
     
       15. The additive of claim  14  wherein R 1  is hydrogen and Y is 0. 
     
     
       16. The additive of claim  15  wherein R 2  is hydrogen. 
     
     
       17. The additive of claim  14  wherein R 1  is the reacted moiety after reaction of the polyene in at least one fatty acid or fatty acid ester. 
     
     
       18. The additive of claim  17  wherein the fatty acid or fatty acid ester is a member selected from the group consisting of oleic acid, linoleic acid, methyl oleate, butyl oleate, butyl tallate, methyl tallate, octyl tallate, glyceryl monooleate, glyceryl monotallate, and pentaerythritol trioleate. 
     
     
       19. The additive of claim  10  wherein the graft copolymer has the structure                    
       where n is an integer in the range of about 1 to about 10. 
     
     
       20. A lubricant comprising a lubricant additive comprising a graft copolymer comprising: 
       a copolymer prepared by the interpolymerization of a mixture of monomers comprising:  
       ethylene,  
       a C 3 -C 12  alpha monoolefin, and a polyene being a member selected from the group consisting of non-conjugated dienes and trienes;  
       having grafted thereon:  
       a 2-mercapto-1,3,4-thiadiazole moiety.  
     
     
       21. The lubricant of claim  20  wherein said lubricant is a lubricating oil. 
     
     
       22. The lubricant of claim  20  wherein the C 3 -C 12  alpha monoolefin is propylene. 
     
     
       23. The lubricant of claim  20  wherein the polyene is a member selected from the group consisting of 1,4-hexadiene; 1,5-hexadiene; 1,4-pentadiene, 2-methyl-1,4-pentadiene; 3-methyl-1,4-hexadiene; 4-methyl-1,3-hexadiene; 1,7-octadiene; 1,9-decadiene; exodicyclopentadiene; endodicyclopentadiene; 5-propenylnorbornene; 5-(buten-2-yl)norbornene; 5-(2-methylbutene-{2′}-yl)norbornene; 5-methyl-6-propenylnorbornene; 5-methylene-2-norbornene; 5-ethylidene-2-norbornene; 5-isopropylidene-2-norbornene; vinylnorbornene; cyclohexenylnorbornene; methylnorbornadiene; ethylnorbornadiene; propylnorbornadiene; 1,5-cyclooctadiene; 1,4-cyclooctadiene; 1-isopropylidene-3a,4,7,7a-tetrahydroindene; 1-isopropylidenedicyclopentadiene; dehydroisodicyclopentadiene; and 2-(2-methylene-4-methyl-3-pentenyl){2.2.1}bicyclo-5-heptene. 
     
     
       24. The lubricant of claim  20  wherein the 2-mercapto-1,3,4-thiadiazole moiety is derived from a compound having the structure                    
       wherein R 1  is hydrogen, alkyl, alkenyl, aryl, alkaryl, aralkyl, or 2-hydroxyalkyl; 
       X is sulfur;  
       Y is 0 or 1; and  
       R 2  is hydrogen or                    
     
     
       25. The lubricant of claim  24  wherein R 1  is hydrogen and Y is 0. 
     
     
       26. The lubricant of claim  25  wherein R 2  is hydrogen. 
     
     
       27. The lubricant of claim  24  wherein R 1  is the reacted moiety after reaction of the polyene in at least one fatty acid or fatty acid ester. 
     
     
       28. The lubricant of claim  27  wherein the fatty acid or fatty acid ester is a member selected from the group consisting of oleic acid, linoleic acid, methyl oleate, butyl oleate, butyl tallate, methyl tallate, octyl tallate, glyceryl monooleate, glyceryl monotallate, and pentaerythritol trioleate. 
     
     
       29. The lubricant of claim  20  wherein the graft copolymer has the structure                    
       where n is an integer in the range of about 1 to about 10.