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 (thio)phosphoric acid salt of an N-hydrocarbyl-substituted gamma- (γ-) or delta-amino(thio)ester.

2. The lubricant of claim 1 , the amino(thio)ester comprises a N-hydrocarbyl-substituted gamma- amino(thio)ester.

3. The lubricant of claim 1 , the amino(thio)ester comprises a N-hydrocarbyl-substituted gamma- aminoester.

4. The lubricant of claim 1 , wherein the amino(thio)ester 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 amino(thio)ester 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 amino(thio)ester 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 amino(thio)ester 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 amino(thio)ester 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 , where R 9 and 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 amino(thio)ester 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 amino(thio)ester 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 (thio)phosphoric acid salt of an N-hydrocarbyl-substituted amino(thio)ester is obtained/obtainable by reacting an N-hydrocarbyl-substituted amino(thio)ester with a (thio)phosphoric acid, ester, or a partial acid-ester thereof.

15. The lubricant composition of claim 14 , wherein the amino(thio)ester 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 (thio)phosphoric acid salt of an N-hydrocarbyl-substituted amino(thio)ester, is obtained/obtainable by reacting the N-hydrocarbyl-substituted N-hydrocarbyl-substituted amino(thio)ester with a (thio)phosphoric acid, ester, or a partial acid-ester thereof.

16. The lubricant of claim 1 , wherein the (thio)phosphoric acid comprises a mono- or di- hydrocarbyl (thio)phosphoric acid, or mixtures thereof.

17. The lubricant of claim 16 , wherein the alkyl of the mono- or di- hydrocarbyl (thio)phosphoric acid comprises linear alkyl groups of 3 to 36 carbon atoms.

18. The lubricant of claim 16 , wherein the alkyl of the mono- or di- hydrocarbyl (thio)phosphoric acid comprises branched alkyl groups of 3 to 36 carbon atoms.

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

20. The lubricant of claim 19 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.

21. The lubricant of claim 20 further comprising a detergent selected from the group consisting of non-sulphur containing phenates, sulphur containing phenates, sulphonates, salixarates, salicylates, borated equivalents thereof and mixtures thereof.

22. The lubricant of claim 21 further comprising a phosphorus-containing antiwear agent.

23. The lubricant of claim 21 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.

24. The lubricant of claim 21 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.

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

26. The method of claim 25 , wherein the internal combustion engine has a steel surface on a cylinder bore, cylinder block, or piston ring.

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

28. The method of claim 25 , 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 %.

29. The method of claim 25 , wherein the lubricant further comprises an overbased sulphonate detergent present at 0.01 wt % to 0.9 wt %.

30. The method of claim 29 , wherein the overbased sulphonate detergent comprises an overbased calcium sulphonate having a metal ratio of 18 to 40.

31. The method of claim 29 , 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, sulphonates, salixarates, salicylates, borated equivalents thereof and mixtures thereof.

32. The method of claim 25 wherein the lubricant further comprises a phosphorus-containing antiwear agent.

33. The method of claim 25 , wherein the lubricant is characterised 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.

34. The method of claim 25 , wherein the lubricant is characterised 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.

35. The method of claim 25 , wherein the lubricant has a sulphated ash content of 0.5 wt % to 1.2 wt %.

36. The method of claim 25 , wherein the lubricant comprises 0.1 wt % to 2 wt % of the (thio)phosphoric acid salt of an N-hydrocarbyl-substituted gamma- (γ-) or delta-amino(thio)ester.

37. The method of claim 25 , 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 sulphonate;

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 (thio)phosphoric 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.

38. The method of claim 37 , 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.

39. The method of claim 25 , 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, containing 1 to 150 carbon atoms.