Antioxidant additive for lubricant compositions, comprising organotungstate
View Patent ↗The invention relates an additive for improving antioxidant capabilities in a lubricating composition, where the lubricating composition is based on a major amount of a lubricating oil and 0.1-5.0 mass percent of an additive, the additive including a secondary diarlyamine and an organoammonium tungstate.
1. A lubricating composition comprising a major amount of a lubricating oil and 0.5-5.0 mass percent of an additive, the additive comprising a secondary diarylamine at about 0.5-2.0 mass percent, and an organoammonium tungstate in an amount which provides about 50-3,000 ppm tungsten, wherein the organoammonium tungstate is a reaction product of (a) a tungsten source and (b) di-(C 11 -C 14 -branched and linear alkyl) amine, or a mono- or bis-substituted succinimide.
2. The lubricating composition of claim 1 , wherein the mass ratio of secondary diarylamine to tungsten is about 75:1 to about 1:3.
3. The lubricating composition of claim 2 , wherein the mass ratio of secondary diarylamine to tungsten is about 35:1 to about 1:3.
4. The lubricating composition of claim 3 , wherein the mass ratio of secondary diarylamine to tungsten is about 16:1 to about 2:1.
5. The lubricating composition of claim 3 , wherein the secondary diarylamine comprises
wherein R 1 , R 2 , R 3 , and R 4 each independently represent hydrogen, alkyl, aralkyl, aryl, and alkaryl groups having 1 to about 20 carbons atoms per each group, wherein X is either (CH 2 ) n , S, or O and n is 0 to 2, or X is two hydrogens bound to their respective carbons in a secondary diphenylamine structure.
6. The lubricating composition of claim 5 , wherein at least one of R 1 , R 2 , R 3 , and R 4 are each independently chosen from hydrogen, 2-methyl propenyl, 2,4,4-trimethyl pentenyl, styrenyl and nonyl.
7. The lubricating composition of claim 5 , wherein the secondary diarlyamine is chosen from octylated/butylated secondary diarylamine, p,p′-dioctylated secondary diarylamine and octylated/styrenated secondary diarylamine.
8. The lubricating composition of claim 1 , wherein the tungsten source is chosen from tungstic acid, tungsten trioxide, ammonium tungstate, ammonium paratungstate, sodium tungstate dihydrate, calcium tungstate and ammonium metatungstate.
9. The lubricating composition of claim 1 , wherein component (b) is the di-(C 11 -C 14 -branched and linear alkyl) amine.
10. The lubricating composition of claim 1 , wherein component (b) is the mono- or bis-substituted succinimide.
11. The lubricating composition of claim 10 , wherein the mono- or bis-substituted succinimide is of the formula:
wherein R 11 is 8 to 400 carbon atoms.
12. The lubricating composition of claim 11 , wherein R 11 is 50 to 200 carbon atoms.
13. The lubricating composition of claim 12 , wherein the mono- or his-substituted succinimide is derived from polyisobutenyl having molecular weight ranging from 800-2,500 grams per mole and a polyethylene amine.