Lubricating oil composition

Patent metadata

Field	Value
Publication number	US-11060046-B2
Application number	US-201615559674-A
Country	US
Kind code	B2
Filing date	Mar 18, 2016
Priority date	Mar 20, 2015
Publication date	Jul 13, 2021
Grant date	Jul 13, 2021

Abstract

The lubricating oil composition of the present invention contains a base oil, a 2,6-di-tert-butylphenol (A), and at least one compound (B) selected from a benzotriazole compound and a sorbitan compound.

First claim

The invention claimed is:

1. A lubricating oil composition, consisting of:
at least one base oil;
a 2,6-di-tert-butylphenol (A) and optionally at least one other phenol-based antioxidant;
a sorbitan compound (B);
optionally at least one benzotriazole compound;
at least one phosphorus-containing extreme pressure agent (C);
optionally at least one succinate compound (D);
optionally at least one amine-based antioxidant (E); and
optionally at least one additive selected from the group consisting of an ash-free dispersant, a viscosity index improver, a pour point depressant, a defoaming agent, a rust inhibitor, a metal inactivator and mixtures thereof,
wherein:
the lubricating oil composition has a kinematic viscosity at 40° C. of 20 to 500 mm 2 /s,
the lubricating oil composition does not contain a metal detergent; and
the at least one base oil includes at least one mineral oil which is grouped in Group 2 or 3 in the base oil category of API (American Petroleum Institute) as a major amount of the at least one base oil;
a content of the base oil is 80 to 99.7% by mass, based on the total amount of the lubricating oil composition;
a content of the 2,6-di-tert-butylphenol (A) is 0.2 to 1.0% by mass, based on a total amount of the lubricating oil composition;
a content of the sorbitan compound (B) is 0.02 to 0.2% by mass, based on the total amount of the lubricating oil composition;
the sorbitan compound (B) includes at least a sorbitan monooleate (B1); and
the ratio by mass of the sorbitan monooleate (B1) to the 2,6-di-tert-butylphenol (A) (B1/A) is from 0.005 to 0.3;
the phosphorus-containing extreme pressure agent (C) is at least one selected from the group consisting of a triaryl phosphate, a dithiophosphate and a phosphate amine salt;
when the phosphorus-containing extreme pressure agent (C) is a phosphate amine salt, a content of the phosphate amine salt is 0.01 to 0.08% by mass, based on the total amount of the lubricating oil composition;
when the phosphorus-containing extreme pressure agent (C) is at least one of a triaryl phosphate and a dithiophosphate, a content of the phosphorus-containing extreme pressure agent (C) is 0.1 to 1.5% by mass, based on the total amount of the lubricating oil composition;
when the lubricating oil composition is tested with a Falex test machine, where a pre-conditioning interim operation is carried out at 1334 N and 290 rpm for 5 minutes, and then under continuous loading of 40 N/sec at 25° C., the load until seizing is 3120 N or more;
when a rotating pressure vessel oxidation test based on JIS K2514 is performed on the lubricating oil composition at 150° C., the time (RPVOT Value) is takes for the vessel pressure to lower by 175 kPA from the maximum pressure before the start of the test is 606 minutes or more;
when the lubricating oil composition is tested according to the method described in ASTM D7873-13, the amount of sludge formation measured using a membrane filter having a mean pore size of 1.0 μm after 480 hours is 0.4 mg/100mL or less.

2. The lubricating oil composition according to claim 1 , wherein a ratio by mass of sorbitan monooleate (B1) to the 2,6-di-tert-butylphenol (A) (B1/A) is from 0.020 to 0.250.

3. The lubricating oil composition according to claim 1 , wherein the sorbitan compound (B) further includes a sorbitan fatty acid partial ester in which the fatty acid has 10 to 22 carbon atoms.

4. The lubricating oil composition according to claim 1 , wherein the lubricating oil composition includes an alkyl-3-(3,5-di-t-butyl-4-hydroxyphenyl)propionate, in which the alkyl has 4 to 20 carbon atoms, as the other phenol-based antioxidant.

5. The lubricating oil composition according to claim 1 , wherein the phosphorus-containing extreme pressure agent (C) is the triaryl phosphate which is at least one selected from the group consisting of tert-butylphenyldiphenyl phosphate and di(tert-butylphenyl)phenyl phosphate.

6. The lubricating oil composition according to claim 1 , which includes the at least one amine-based antioxidant (E).

7. The lubricating oil composition according to claim 6 , wherein the amine-based antioxidant (E) is a compound represented by formula (E-1):
Ar 1 —NH—Ar 2   (E-1)

wherein Ar 1 and Ar 2 each independently represent an aryl group having 6 to 24 carbon atoms selected from the group consisting of a phenyl group, an alkyl-substituted phenyl group substituted with an alkyl group, a naphthyl group, an alkyl-substituted naphthyl group substituted with an alkyl group, and an aralkyl-substituted phenyl group substituted with an aralkyl group.

8. The lubricating oil composition according to claim 6 , wherein the amine-based antioxidant (E) is at least one phenyl-α-naphthylamine represented by formula (E-2):

wherein R 21 represents a hydrogen atom, or an alkyl group having 1 to 18 carbon atoms.

9. The lubricating oil composition according to claim 6 , wherein the amine-based antioxidant (E) is contained in an amount of 0.02 to 1.0% by mass based on the total amount of the composition.

10. The lubricating oil composition according to claim 1 , which is a lubricating oil for rotary appliances, or a hydraulic actuation oil.

11. A method for producing a lubricating oil composition, the method consisting of blending at least one base oil with a mixture consisting of:
a 2,6-di-tert-butylphenol (A) and optionally at least one other phenol-based antioxidant;
a sorbitan compound (B);
optionally at least one benzotriazole compound;
at least one phosphorus-containing extreme pressure agent (C); and
optionally at least one succinate compound (D)
optionally at least one amine-based antioxidant (E); and
optionally at least one additive selected from the group consisting of an ash-free dispersant, a viscosity index improver, a pour point depressant, a defoaming agent, a rust inhibitor, a metal inactivator and mixtures thereof, to obtain the lubricating oil composition,
wherein:
the lubricating oil composition has a kinematic viscosity at 40° C. of 20 to 500 mm 2 /s,
the lubricating oil composition does not contain a metal detergent; and
the at least one base oil includes at least one mineral oil which is grouped in Group 2 or 3 in the base oil category of API (American Petroleum Institute) as a major amount of the at least one base oil;
a content of the base oil is 80 to 99.7% by mass, based on the total amount of the lubricating oil composition;
a content of the 2,6-di-tert-butylphenol (A) is 0.2 to 1.0% by mass, based on a total amount of the lubricating oil composition;
a content of the sorbitan compound (B) is 0.02 to 0.2% by mass, based on the total amount of the lubricating oil composition;
the sorbitan compound (B) includes at least a sorbitan monooleate (B1); and
the ratio by mass of the sorbitan monooleate (B1) to the 2,6-di-tert-butylphenol (A) (B1/A) is from 0.005 to 0.3;
the phosphorus-containing extreme pressure agent (C) is at least one selected from the group consisting of a triaryl phosphate, a dithiophosphate and a phosphate amine salt;
when the phosphorus-containing extreme pressure agent (C) is a phosphate amine salt, a content of the phosphate amine salt is 0.01 to 0.08% by mass, based on the total amount of the lubricating oil composition;
when the phosphorus-containing extreme pressure agent (C) is at least one of a triaryl phosphate and a dithiophosphate, a content of the phosphorus-containing extreme pressure agent (C) is 0.1 to 1.5% by mass, based on the total amount of the lubricating oil composition;
when the lubricating oil composition is tested with

Assignees

• Idemitsu Kosan Co

Inventors

• Shinoda Jitsuo

Classifications

• C10M141/06 Primary

  at least one of them being an organic nitrogen-containing compound · CPC title

• C10M2223/041

  Triaryl phosphates · CPC title

• C10N2030/02

  Pour-point; Viscosity index · CPC title

• C10M2215/30

  Heterocyclic compounds · CPC title

• C10M2207/283

  of polyhydroxy compounds · CPC title