Lubricating oil composition

Patent metadata

Field	Value
Publication number	US-9410106-B2
Application number	US-201314384837-A
Country	US
Kind code	B2
Filing date	Mar 11, 2013
Priority date	Mar 12, 2012
Publication date	Aug 9, 2016
Grant date	Aug 9, 2016

Abstract

A lubricating oil composition containing a base oil having a kinematic viscosity at 40 degrees C. in a range from 10 mm 2 /s to 1000 mm 2 /s with: (A) at least one of phosphorus compounds represented by a formula (1) in an amount of 0.001 mass % to 0.3 mass % in terms of a phosphorus content; (B) at least one of a sulfur compound represented by a formula (2) and a sulfur compound that comprises a dithio (—S—S—) bond in a molecule in an amount of 0.01 mass % to 0.5 mass % in terms of a sulfur content, the latter sulfur compound, when added to the base oil in an amount of 1 mass %, leading to a rating of 2 or lower in a copper strip corrosion test; and (D) a succinimide derivative in an amount of 0.01 mass % to 1 mass %.

First claim

The invention claimed is:

1. A lubricating oil composition comprising:
a base oil having a kinematic viscosity at 40 degrees C. in a range from 10 mm 2 /s to 1000 mm 2 /s;
(A) a phosphorus compound represented by a formula (1) in an amount of 0.001 mass % to 0.3 mass % in terms of a phosphorus content,

where: R is a hydrogen atom or an alkyl group having 3 or less carbon atoms; and X is an oxygen atom or a sulfur atom;
(B) at least one sulfur compound selected from the group consisting of a thiophosphate compound, a dithiophosphate compound and a sulfur compound (B-2) comprising a dithio (—S—S—) bond in a molecule in an amount of 0.01 mass % to 0.5 mass % in terms of a sulfur content, the sulfur compound (B-2), when added to the base oil in an amount of 1 mass %, leading to a rating of 2 or lower in a copper strip corrosion test under JIS K 2513, at 100 degrees C. for three hours,
(C) a carboxylic acid amide with an acid number of 10 mg KOH/g or less in an amount of 0.01 mass % to 0.5 mass %; and
(D) a succinimide derivative in an amount of 0.01 mass % to 1 mass %,
wherein an acid number of the lubricating oil composition is in a range from 0.01 mg KOH/g to 0.05 mg KOH/g.

2. The lubricating oil composition according to claim 1 , wherein said composition comprises said sulfur compound (B-2) comprising a polythio bond not smaller than a trithio (—S—S—S—) bond in an amount of 1 mass % or less of a total amount of the sulfur compound (B-2).

3. The lubricating oil composition according to claim 1 , wherein the succinimide derivative (D) comprises an alkyl group or an alkenyl group in a side chain, the side chain having a number average molecular weight in a range from 500 to 3000.

4. The lubricating oil composition according to claim 1 , wherein the base oil comprises a base oil categorized into Group II or Group III of base oil categories according to API.

5. The lubricating oil composition according to claim 1 , wherein the base oil comprises a poly-alpha-olefin (PAO).

6. The lubricating oil composition according to claim 1 , wherein an acid number of the lubricating oil composition is in a range from 0.02 mg KOH/g to 0.04 mg KOH/g.

7. A hydraulic oil comprising the lubricating oil composition according to claim 1 .

8. A hydraulic oil suitable for a hydraulic drive train used in a wind power generator, the hydraulic oil comprising the lubricating oil composition according to claim 7 .

9. The lubricating oil composition according to claim 1 , comprising the thiophosphate compound.

10. The lubricating oil composition according to claim 1 , comprising the dithiophosphate compound.

11. The lubricating oil composition according to claim 1 , comprising the sulfur compound (B-2).

12. A lubricating oil composition comprising:
a base oil having a kinematic viscosity at 40 degrees C. in a range from 10 mm 2 /s to 1000 mm 2 /s;
(A) a phosphorus compound represented by a formula (1) in an amount of 0.001 mass % to 0.3 mass % in terms of a phosphorus content,

where: R is a hydrogen atom or an alkyl group having 3 or less carbon atoms; and X is an oxygen atom or a sulfur atom;
(B) at least one sulfur compound selected from the group consisting of a thiophosphate compound, a dithiophosphate compound and a sulfur compound (B-2) comprising a dithio (—S—S—) bond in a molecule in an amount of 0.01 mass % to 0.5 mass % in terms of a sulfur content, the sulfur compound (B-2), when added to the base oil in an amount of 1 mass %, leading to a rating of 2 or lower in a copper strip corrosion test under JIS K 2513, at 100 degrees C. for three hours, and
(D) a succinimide derivative in an amount of 0.01 mass % to 1 mass %,
said composition further comprising (C′) a carboxylic acid amide in such an amount that a pH of eluted water according to JIS Z 8802 is in a range from 6 to 8,
and wherein an acid number of the lubricating oil composition is in a range from 0.01 mg KOH/g to 0.05 mg KOH/g.

13. The lubricating oil composition according to claim 12 , further comprising (C) a carboxylic acid amide with an acid number of 10 mg KOH/g or less in an amount of 0.01 mass % to 0.5 mass %.

14. The lubricating oil composition according to claim 12 , wherein said composition comprises said sulfur compound (B-2) comprising a polythio bond not smaller than a trithio (—S—S—S—) bond in an amount of 1 mass % or less of a total amount of the sulfur compound (B-2).

15. The lubricating oil composition according to claim 12 , wherein the succinimide derivative (D) comprises an alkyl group or an alkenyl group in a side chain, the side chain having a number average molecular weight in a range from 500 to 3000.

16. The lubricating oil composition according to claim 12 , wherein the base oil comprises a base oil categorized into Group II or Group III of base oil categories according to API.

17. The lubricating oil composition according to claim 12 , wherein the base oil comprises a poly-alpha-olefin (PAO).

18. The lubricating oil composition according to claim 12 , comprising the thiophosphate compound.

19. The lubricating oil composition according to claim 12 , comprising the dithiophosphate compound.

20. The lubricating oil composition according to claim 12 , comprising the sulfur compound (B-2).

Assignees

• Idemitsu Kosan Co

Inventors

• KIKO Yumiko
• Okada Tahei

Classifications

• C10N2030/06

  Oiliness; Film-strength; Anti-wear; Resistance to extreme pressure · CPC title

• C10N2030/26

  Waterproofing or water resistance · CPC title

• C10N2030/36

  Seal compatibility, e.g. with rubber · CPC title

• C10N2030/12

  Inhibition of corrosion, e.g. anti-rust agents or anti-corrosives · CPC title

• C10N2030/04

  Detergent property or dispersant property · CPC title