Lubricant base oil
View Patent ↗Disclosed is lubricant base oil that is excellent in lubricity, sludge solubility, low viscosity, and low temperature characteristics and capable of realizing low volatility. The lubricant base oil contains as its main component a diester or triester synthesized from a divalent or trivalent carboxylic acid of 9 or less carbon atoms and a monovalent glycol ether such as an alkylene glycol monoalkyl ether of 3 to 25 carbon atoms and is useful as base oil for lubricating oil and grease. Di(hexyloxyethyl) adipate may be cited as an appropriate example of the diester.
1. Lubricant base oil comprising a diester synthesized from a divalent aliphatic carboxylic acid of 9 or less carbon atoms and a monovalent alkylene glycol monoalkyl ether of 3 to 25 carbon atoms represented by the following formula (1):
HO—R1-O—R2 (1)
where R1 is an alkylene group represented by C p H 2p , R2 is an alkyl group represented by C n H2 n+1 , p is in the range of 1 to 5, and n is in the range of 1 to 12.
2. Lubricant base oil as described in claim 1 wherein at least one of the carboxylic acid and the monovalent glycol ether has an alkyl group of branched structure.
3. Lubricant base oil as described in claim 1 wherein the diester is di(hexyloxyethyl) adipate.
4. Lubricant base oil as described in claim 1 wherein the diester is di(butoxypropyl) azelate.
5. Lubricant base oil as described in claim 1 wherein the diester is di(hexyloxyethyl) methyladipate.
6. A grease comprising the lubricant base oil described in claim 1 and a thickener.
7. Lubricant base oil comprising a diester synthesized from a divalent aliphatic carboxylic acid of 9 or less carbon atoms and a monovalent glycol ether represented by the following formula (1);
HO—R1-O—R2 (1)
where R1 is a 1-methylethylene group or a 2-methylethylene group and R2 is an alkyl group of 1 to 12 carbon atoms.
8. A grease comprising the lubricant base oil described in claim 7 and a thickener.
9. A grease comprising the lubricant base oil as described in claim 2 and a thickener.
10. A grease comprising the lubricant base oil as described in claim 3 and a thickener.
11. A grease comprising the lubricant base oil as described in claim 4 and a thickener.
12. A grease comprising the lubricant base oil as described in claim 5 and a thickener.
13. The lubricant base oil as described in claim 1 wherein the divalent aliphatic carboxylic acid is a divalent aliphatic carboxylic of 6-9 carbon atoms.
14. The lubricant base oil as described in claim 1 wherein the monovalent alkylene glycol monoalkyl ether is monovalent alkylene glycol monoalkyl ether represented by the following formula (1):
HO—R1-O—R2 (1)
where R1 is an alkylene group represented by C p H 2p , R2 is an alkyl group represented by C n H2 n+ , p is in the range of 1 to 5, and n is in the range of 1 to 12.
15. The lubricant base oil as described in claim 1 wherein the divalent aliphatic carboxylic acid is a divalent aliphatic carboxylic acid of 6-9 carbon atoms and the monovalent alkylene glycol monoalkyl ether is divalent aliphatic carboxylic acid represented by the following formula (1):
HO—R1-O—R2 (1)
where R1 is an alkylene group represented by C p H 2p , R2 is an alkyl group represented by C n H2 n+ , p is in the range of 1 to 5, and n is in the range of 1 to 12.
16. The lubricant base oil as described in claim 1 wherein the diester is diester represented by the following (2):
R2-O—R1-O—OC—R—CO—O—R1-O—R2 (2)
where R is an aliphatic group of 4-7 carbon atoms, R1 is an alkylene group represented by C p H 2p , R2 is an alkyl group represented by C n H2 n+ , p is in the range of 1 to 5, and n is in the range of 1 to 12.
17. The lubricant base oil as described in claim 1 wherein the diester is diester represented by the following (2):
R2-O—R1-O—OC—R—CO—O—R1-O—R2 (2)
where R is an alkylene group of 4-7 carbon atoms, R1 is an alkylene group represented by C p H 2p , R2 is an alkyl group represented by C n H2 n+l , p is in the range of 1 to 5, and n is in the range of 1 to 12.
18. The lubricant base oil as described in claim 1 wherein the divalent aliphatic carboxylic acids include oxalic acid, malonic acid, succinic acid, glutaric acid, adipic acid, pimelic acid, suberic acid, azelaic acid, dimethylsuccinic acid, methyladipic acid and dimethylglutaric acid.
19. The grease according to claim 6 wherein the thickener is lithium stearate.
20. The grease according to claim 8 wherein the thickener is lithium stearate.