Lubricant composition containing an antiwear agent

1. A lubricant composition comprising an oil of lubricating viscosity and 0.01 wt % to 15 wt % of a protic acid salt of an N-hydrocarbyl-substituted gamma- (γ-) or delta- (δ-) aminoester.

2. The lubricant of claim 1 , the aminoester comprises a N-hydrocarbyl-substituted gamma- aminoester.

3. The lubricant of claim 1 , the aminoester comprises a N-hydrocarbyl-substituted gamma- aminoester.

4. The lubricant of claim 1 , wherein the aminoester has a N-hydrocarbyl substituent that comprises a hydrocarbyl group of at least 3 carbons atoms, with a branch at the 1 or 2 position of the hydrocarbyl group, provided that if the ester or thioester is a methyl ester or methyl thioester then the hydrocarbyl group has a branch at the 1 position, and further provided that the hydrocarbyl group is not a tertiary group.

5. The lubricant composition of claim 4 , wherein the aminoester comprises a 2-((hydrocarbyl)aminomethyl) succinic acid dihydrocarbyl ester.

6. The lubricant composition of claim 4 , wherein the ester functionality comprises an alcohol-derived group which is a hydrocarbyl group having 1 to about 30 carbon atoms.

7. The lubricant composition of claim 4 wherein the ester functionality comprises an alcohol-derived group which is an ether-containing group.

8. The lubricant composition of claim 1 , wherein the aminoester comprises first and second ester functionalities, and wherein the first and second ester functionalities each comprise an alcohol-derived groups having an alkyl moiety which is the same or different and having 1 to about 18 carbon atoms.

9. The lubricant composition of claim 1 , wherein the aminoester is represented by the formula

wherein n is 0 or 1, R 1 is hydrogen or a hydrocarbyl group, R 2 and R 3 are independently hydrocarbyl groups or together form a carbocyclic structure, X is O or S, R 4 is a hydrocarbyl group of 1 to about 30 carbon atoms, and R 5 is hydrogen, a hydrocarbyl group, or a group represented by —C(═O)—R 6 where R 6 is hydrogen, an alkyl group, or —X′—R 7 , where X′ is O or S and R 7 is a hydrocarbyl group of 1 to about 30 carbon atoms, provided that if R 4 is methyl, then n is 0, and further provided that if n is 0, R 1 is hydrogen.

10. The lubricant composition of claim 1 , wherein the aminoester is represented by the formula

wherein n is 0 or 1, R 1 is hydrogen or a hydrocarbyl group, R 2 and R 3 are independently hydrocarbyl groups or together form a carbocyclic structure, X is O or S, R 4 is an ether-containing group or a polyether-containing group, having 2 to about 120 carbon atoms, and R 5 is hydrogen, a hydrocarbyl group, or a group represented by —C(═O)—R 6 where R 6 is hydrogen, an alkyl group, or —X′—R 7 , where X′ is O or S and R 7 is a hydrocarbyl group of 1 to about 30 carbon atoms, provided that if R 4 is methyl, then n is 0, and further provided that if n is 0, R 1 is hydrogen.

11. The lubricant composition of claim 10 , wherein R 4 is represented by

wherein R 6 is a hydrocarbyl group of 1 to about 30 carbon atoms;

R 7 is H or a hydrocarbyl group of 1 to about 10 carbon atoms;

R 8 is a straight or branched chain hydrocarbylene group of 1 to 6 carbon atoms;

Y is —H, —OH, —R 6 OH, —NR 9 R 10 , or —R 6 NR 9 R 10 are each independently

H or a hydrocarbyl group of 1 to 50 carbon atoms, and

m is an integer from 2 to 50.

12. The lubricant composition of claim 1 , wherein the aminoester is represented by the formula

wherein n is 0 or 1, R 1 is hydrogen or a hydrocarbyl group, R 2 and R 3 are independently hydrocarbyl groups or together form a carbocyclic structure, X is O or S, R 4 is a hydroxy-containing or a polyhydroxy-containing alkyl group of 2 to about 12 carbon atoms, at least one hydroxy group being optionally reacted to form an ester or a thioester, and R 5 is hydrogen, a hydrocarbyl group, or a group represented by —C(═O)—R 6 where R 6 is hydrogen, an alkyl group, or —X′—R 7 , where X′is O or S and R 7 is a hydrocarbyl group of 1 to about 30 carbon atoms, provided that if R 4 is methyl, then n is 0, and further provided that if n is 0, R 1 is hydrogen.

13. The lubricant composition of claim 12 , wherein the aminoester is represented by the formula

wherein R 2 and R 3 are independently alkyl groups of 1 to about 6 carbon atoms and R 4 and R 7 are independently alkyl groups of 1 to about 12 carbon atoms.

14. The lubricant composition of claim 1 , wherein the protic acid salt of an N-hydrocarbyl-substituted aminoester is obtained/obtainable by reacting an N-hydrocarbyl-substituted aminoester with a protic acid, ester, or a partial acid-ester thereof.

15. The lubricant composition of claim 14 , wherein the aminoester has a N-hydrocarbyl substituent that comprises a hydrocarbyl group of at least 3 carbons atoms, with a branch at the 1 or 2 position of the hydrocarbyl group, provided that if the ester or thioester is a methyl ester or methyl thioester then the hydrocarbyl group has a branch at the 1 position, and further provided that the hydrocarbyl group is not a tertiary group protic acid salt of an N-hydrocarbyl-substituted aminoester, is obtained/obtainable by reacting the N-hydrocarbyl-substituted N-hydrocarbyl-substituted aminoester with a protic acid, ester, or a partial acid-ester thereof.

16. The lubricant of claim 1 , wherein the protic acid is a boric acid, salicylic acid, or sulfonic acid.

17. The lubricant of claim 1 , wherein the oil of lubricating viscosity comprises API Group I, II, III, IV, V, or mixtures thereof.

18. The lubricant of claim 17 further comprising at least one of a succinimide dispersant, a Mannich dispersant, a succinamide dispersant, a polyolefin succinic acid ester, amide, or ester-amide dispersant, or mixtures thereof.

19. The lubricant of claim 18 further comprising a detergent selected from the group consisting of non-sulphur containing phenates, sulphur containing phenates, sulfonates, salixarates, salicylates, borated equivalents thereof and mixtures thereof.

20. The lubricant of claim 19 further comprising a phosphorus-containing antiwear agent.

21. The lubricant of claim 19 further comprising a viscosity modifier selected from the group consisting of hydrogenated styrene-butadiene rubbers, ethylene-propylene copolymers, polymethacrylates, polyacrylates, hydrogenated styrene-isoprene polymers, hydrogenated diene polymers, polyalkyl styrenes, polyolefins, esters of maleic anhydride-olefin copolymers, esters of maleic anhydride-styrene copolymers, and mixtures thereof.

22. The lubricant of claim 19 further comprising a corrosion inhibitor selected from the group consisting of a derivative of benzotriazole, 1,2,4-triazole, benzimidazole, 2-alkyldithiobenzimidazole or 2 -alkyldithiobenzothiazole, 1-amino-2-propanol, a derivative of dimercaptothiadiazole, octylamine octanoate, condensation products of dodecenyl succinic acid or anhydride or a fatty acid with a polyamine, and mixtures thereof.

23. A method of lubricating an internal combustion engine comprising supplying to the internal combustion engine a lubricant of claim 1 .

24. The method of claim 23 , wherein the internal combustion engine has a steel surface on a cylinder bore, cylinder block, or piston ring.

25. The method of claim 23 , wherein the internal combustion engine has a surface of steel, or an aluminum alloy, or an aluminum composite.

26. The method of claim 23 , wherein the lubricant further comprises a phenolic or an aminic antioxidant or mixtures thereof, and wherein the antioxidant is present at 0.1 wt % to 3 wt %.

27. The method of claim 23 , wherein the lubricant further comprises an overbased sulfonate detergent present at 0.01 wt % to 0.9 wt %.

28. The method of claim 27 , wherein the overbased sulfonate detergent comprises an overbased calcium sulfonate having a metal ratio of 18 to 40.

29. The method of claim 27 , wherein the lubricant further comprises 0.01 wt % to 2 wt % of a second detergent wherein the second detergent is selected from the group consisting of non-sulphur containing phenates, sulphur containing phenates, sulfonates, salixarates, salicylates, borated equivalents thereof and mixtures thereof.

30. The method of claim 23 wherein the lubricant further comprises zinc dialkyldithiophosphate.

31. The method of claim 23 , wherein the lubricant is characterized as having (i) a sulphur content of 0.5 wt % or less, (ii) a phosphorus content of 0.15 wt % or less, and (iii) a sulphated ash content of 0.5 wt % to 1.5 wt % or less.

32. The method of claim 23 , wherein the lubricant is characterized as having at least one of (i) a sulphur content of 0.2 wt % to 0.4 wt % or less, (ii) a phosphorus content of 0.08 wt % to 0.15 wt %, and (iii) a sulphated ash content of 0.5 wt % to 1.5 wt % or less.

33. The method of claim 23 , wherein the lubricant has a sulphated ash content of 0.5 wt % to 1.2 wt %.

34. The method of claim 23 , wherein the lubricant comprises 0.1 wt % to 2 wt % of the protic acid salt of an N-hydrocarbyl-substituted gamma- (γ-) or delta-amino(thio)ester.

35. The method of claim 23 , wherein the lubricant comprises:

0.1 wt % to 6 wt % of an overbased detergent chosen from a calcium or magnesium non-sulphur containing phenate, a calcium or magnesium a sulphur containing phenate, or a calcium or magnesium sulfonate;

0.5 wt % to 10 wt % of a polyisobutylene succinimide, wherein the polyisobutylene of the polyisobutylene succinimide has a number average molecular weight of 550 to 3000;

0.05 wt % to 5 wt % of an ethylene-propylene copolymer;

0.1 wt % to 5 wt % of the protic acid salt of an N-hydrocarbyl-substituted gamma- (γ-) or delta- amino(thio)ester; and

zinc dialkyldithiophosphate present in an amount to deliver 100 ppm to 800 ppm of phosphorus.

36. The method of claim 35 , wherein the lubricant has a SAE viscosity grade of XW-Y, wherein X is 0, 5, 10, or 15; and Y is 16, 20, 30, or 40.

37. The method of claim 23 , wherein the lubricant further comprises

0.01 to 5 wt % or 0.1 to 2 wt % of an ashless antiwear agent represented by Formula:

wherein

Y and Y′ are independently —O—, >NH, >NR 3 , or an imide group formed by taking together both Y and Y′ groups and forming a R 1 -N<group between two >C═O groups;

X is independently —Z—O—Z′-, >CH 2, > CHR 4 , >CR 4 R 5 , >C(OH)(CO 2 R 2 ), >C(CO 2 R 2 ) 2 , or >CHOR 6 ;

Z and Z′ are independently >CH 2, > CHR 4 , >CR 4 R 5 , >C(OH)(CO 2 R 2 ), or >CHOR 6 ;

n is 0 to 10, with the proviso that when n═1, X is not >CH 2 , and when n═2, both X′s are not >CH 2;

m is 0 or 1;

R 1 is independently hydrogen or a hydrocarbyl group, typically containing 1 to 150 carbon atoms, with the proviso that when R 1 is hydrogen, m is 0, and n is more than or equal to 1;

R 2 is a hydrocarbyl group, typically containing 1 to 150 carbon atoms;

R 3 , R 4 and R 5 are independently hydrocarbyl groups; and

R 6 is hydrogen or a hydrocarbyl group, typically containing 1 to 150 carbon atoms.