Grease compositions comprising estolide base oils
Provided herein are grease compositions comprising at least one estolide compound of formula: in which n is an integer equal to or greater than 0; m is an integer equal to or greater than 2; R 1 , independently for each occurrence, is selected from optionally substituted alkyl that is saturated or unsaturated, and branched or unbranched; R 2 is selected from hydrogen and optionally substituted alkyl that is saturated or unsaturated, and branched or unbranched; and R 3 and R 4 , independently for each occurrence, are selected from optionally substituted alkyl that is saturated or unsaturated, and branched or unbranched. Also provided are methods of making estolide-based grease products.
1. A grease composition comprising
equal to or greater than 30% by weight of an estolide base oil; and
at least one thickener comprising one or more of a simple metal soap or a complex metal soap,
wherein said estolide base oil comprises at least one estolide compound selected from compounds of Formula I:
wherein
x is, independently for each occurrence, an integer selected from 7 and 8;
y is 0 for each occurrence;
n is an integer selected from 0 to 12;
R 1 is an optionally substituted alkyl that is saturated or unsaturated, and branched or unbranched; and
R 2 is an unsubstituted alkyl that is saturated or unsaturated, and branched or unbranched,
wherein each fatty acid chain residue of said at least estolide one compound is independently optionally substituted.
2. The grease composition according to claim 1 , wherein
n is an integer selected from 0 to 8;
R 1 is an optionally substituted C 1 to C 22 alkyl that is saturated or unsaturated, and branched or unbranched; and
R 2 is an unsubstituted C 1 to C 22 alkyl that is saturated or unsaturated, and branched or unbranched,
wherein each fatty acid chain residue is unsubstituted.
3. The grease composition according to claim 2 , wherein
n is an integer selected from 0 to 6.
4. The grease composition according to claim 1 , wherein R 2 is a branched C 1 to C 20 alkyl that is saturated or unsaturated.
5. The grease composition according to claim 4 , wherein R 2 is saturated.
6. The grease composition according to claim 4 , wherein R 2 is selected from C 6 to C 12 alkyl.
7. The grease composition according to claim 6 , wherein R 2 is 2-ethylhexyl.
8. The grease composition according to claim 1 , wherein R 1 is an unbranched C 1 to C 20 alkyl that is saturated or unsaturated, and unsubstituted.
9. The grease composition according to claim 8 , wherein R 1 is saturated.
10. The grease composition according to claim 8 , wherein R 1 is selected from unsubstituted C 7 to C 17 alkyl that is unbranched and saturated or unsaturated.
11. The grease composition according to claim 10 , wherein R 1 is selected from saturated C 7 alkyl, saturated C 9 alkyl, saturated C 11 alkyl, saturated C 13 alkyl, saturated C 15 alkyl, and saturated or unsaturated C 17 alkyl, which are unsubstituted and unbranched.
12. The grease composition according to claim 1 , wherein said estolide base oil has an EN selected from an integer or fraction of an integer that is equal to or greater than 3, wherein EN is the average number of estolide linkages in compounds according to Formula I.
13. The grease composition according to claim 1 , wherein said estolide base oil has a pour point of less than −35° C.
14. The grease composition according to claim 1 , wherein the at least one thickener comprises one or more of a simple lithium soap or a complex lithium soap.
15. The grease composition according to claim 14 , wherein the at least one thickener comprises one or more of lithium stearate, lithium 12-hydroxy stearate, lithium 16-hydroxystearate, or lithium ricinoleate.
16. The grease composition according to claim 14 , wherein the at least one thickener comprises a reaction product of at least one metal-based material and at least one carboxylic acid or carboxylic acid ester.
17. The grease composition according to claim 16 , wherein the at least one metal-based material comprises one or more of a metal hydroxide, a metal carbonate, a metal bicarbonate, or a metal oxide.
18. The grease composition according to claim 16 , wherein the metal of the at least one metal-based material comprises one or more of an alkali metal or alkaline earth metal.
19. The grease composition according to claim 16 , wherein the at least one carboxylic acid comprises a C 1 -C 40 fatty acid.
20. The grease composition according to claim 1 , wherein said composition further comprises at least one additive.
21. The grease composition according to claim 20 , wherein the at least one additive comprises one or more of a preservative, an antioxidant, a colorant, an anti-weld agent, an extreme pressure agent, a flame retardant, a rust inhibitor, a corrosion inhibitor, an oil bleed inhibitor, a metal deactivator, a viscosity modifier, a tackifier, or a pour point depressant.
22. The grease composition according to claim 20 , wherein the at least one additive comprises one or more of a sulfurized fat, a sulfurized glyceridic oil, a sulfurized vegetable oil, a sulfurized fatty acid, or a sulfurized fatty acid ester.
23. The grease composition according to claim 20 , wherein the at least one additive comprises an anti-wear agent.
24. The grease composition according to claim 23 , wherein the anti-wear agent comprises one or more of zinc dialkyl-1-dithiophosphate, an antimony dialkyl dithiocarbamate, or an amine neutralized alkyl phosphate.
25. The grease composition according to claim 24 , wherein the anti-wear agent comprises an antimony dialkyl dithiocarbamate.
26. The grease composition according to claim 20 , wherein the at least one additive comprises an antioxidant.
27. The grease composition according to claim 26 , wherein the antioxidant comprises one or more of an alkylated diphenyl amine, zinc diamyl dithiocarbamate or butylated hydroxyl toluene.
28. The grease composition according to claim 27 , wherein the antioxidant comprises butylated hydroxyl toluene.
29. The grease composition according to claim 20 , wherein the at least one additive comprises an anti-wear agent and an antioxidant.
30. The grease composition according to claim 1 , wherein the estolide base oil comprises greater than or equal to 50% by weight of the grease composition.
31. The grease composition according to claim 1 , wherein the estolide base oil comprises 30% to 95% by weight of the grease composition.
32. The grease composition according to claim 1 , wherein the estolide base oil comprises 50% to 95% by weight of the grease composition.
33. The grease composition according to claim 1 , wherein the at least one thickener comprises greater than or equal to 5% by weight of the grease composition.
34. The grease composition according to claim 1 , wherein the at least one thickener comprises 5% to 15% by weight of the grease composition.
35. The grease composition according to claim 1 , wherein the at least one thickener comprises greater than 10% by weight of the grease composition.
36. The grease composition according to claim 1 , wherein said composition comprises
1% to 30% by weight of the at least one thickener;
0% to 15% by weight of at least one anti-wear agent; and
0% to 5% by weight of at least one antioxidant.
37. The grease composition according to claim 36 , wherein said composition comprises
5% to 15% by weight of the at least one thickener;
1% to 5% by weight of the at least one anti-wear agent; and
0.4% to 2% by weight of the at least one antioxidant.
38. The grease composition according to claim 1 , wherein said composition further comprises at least one mineral oil.
39. The grease composition according to claim 1 , wherein said grease composition exhibits a dropping point of equal to or greater than 200° C.
40. The grease composition according to claim 3 , wherein x is, independently for each occurrence, an integer selected from 7 and 8.
41. The grease composition according to claim 1 , wherein the at least one thickener comprises one or more of a simple calcium soap or a complex calcium soap.
42. The grease composition according to claim 41 , wherein the at least one thickener comprises one or more of calcium stearate, calcium 12-hydroxy stearate, calcium 16-hydroxystearate, or calcium ricinoleate.
43. The grease composition according to claim 41 , wherein the at least one thickener comprises a reaction product of at least one metal-based material and at least one carboxylic acid or carboxylic acid ester.
44. The grease composition according to claim 42 , wherein the at least one metal-based material comprises one or more of a metal hydroxide, a metal carbonate, a metal bicarbonate, or a metal oxide.
45. The grease composition according to claim 42 , wherein the metal of the at least one metal-based material comprises one or more of an alkali metal or alkaline earth metal.