Antioxidant synergist for lubricating compositions
View Patent ↗Molybdenum-free lubricating compositions are provided, having an antioxidation additive composition based on a combination of (1) alkylated diphenylamine (APDA), (2) polyamine dispersant, and (3) monoglyceride, ethoxylated amide, or mixtures thereof. Further synergy is achieved when component (3) is borated, allowing a reduction in phosphorus levels to below 0.08% or even a phosphorus-free composition.
1. A lubricating composition, comprising:
a major portion of a lubricating base oil, and
an additive composition comprising, as a percentage of the lubricating composition:
(1) an alkylated diphenylamine, at about 0.25 to about 1.0 mass %, of the following formula
wherein R 1 is chosen from alkyl and alkaryl groups having from 4 to 9 carbons atoms per each group, R 4 is chosen from hydrogen, alkyl and alkaryl groups having from 4 to 9 carbons atoms per each group, and R 2 and R 3 are each hydrogen;
(2) a 3:7 mass ratio mixture of C 6 -C 18 monoglyceride and C 6 -C 18 di-ethoxylated amide, at about 0.5 to about 2.0 mass %; and
(3) a monosuccinimide or di-succinimide dispersant, at about 2 to about 5 mass %;
wherein the lubricating composition is free of molybdenum, and wherein the phosphorus level in the lubricating composition is from 0 to less than 0.08 mass %.
2. The lubricating composition of claim 1 , further comprising phosphorus at between about 0.01 up to 0.08 mass %.
3. The lubricating composition of claim 2 , comprising phosphorus at about 0.03-0.07 mass %.
4. The lubricating composition of claim 1 , wherein the lubricating composition is free of phosphorus.
5. A lubricating composition, comprising:
a major portion of a lubricating base oil, and
an additive composition comprising, as a percentage of the lubricating composition:
(1) an alkylated diphenylamine, at about 0.25 to about 1.0 mass %, of the following formula
wherein R 1 is chosen from alkyl and alkaryl groups having from 4 to 9 carbons atoms per each group, R 4 is chosen from hydrogen, alkyl and alkaryl groups having from 4 to 9 carbons atoms per each group, and R 2 and R 3 are each hydrogen;
(2) a 3:7 mass ratio of a borated mixture of C 6 -C 18 monoglyceride and C 6 -C 18 di-ethoxylated amide, at about 0.5 to about 2.0 mass %; and
(3) a monosuccinimide or di-succinimide dispersant, at about 2 to about 5 mass %;
wherein the lubricating composition is free of molybdenum, and wherein the phosphorus level in the lubricating composition is from 0 to less than 0.08 mass %.
6. The lubricating composition of claim 5 , further comprising phosphorus at between about 0.01 up to 0.08 mass %.
7. The lubricating composition of claim 6 , comprising phosphorus at about 0.03-0.07 mass %.
8. The lubricating composition of claim 5 , wherein the lubricating composition is free of phosphorus.
9. The lubricating composition of claim 1 , wherein the R 1 and R 4 are independently chosen from 2-methyl propenyl, 2,4,4-trimethyl pentenyl and nonyl groups.
10. The lubricating composition of claim 5 , wherein the R 1 and R 4 are independently chosen from 2-methyl propenyl, 2,4,4-trimethyl pentenyl and nonyl groups.