# US 2016/0257902 A1 · Lubricating oil composition

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- Number: US 2016/0257902 A1
- Document ID: US20160257902A1
- Status: Published application
- Kind: A1
- Application number: 15/032,177
- Filed: 2014-10-30
- Published: 2016-09-08
- Earliest claimed: 2013-10-30
- Assignees: Idemitsu Kosan Co., Ltd.
- Applicants: Idemitsu Kosan Co., Ltd.
- Inventors: Takuya ONO; Tahei OKADA
- Web page: https://patentgrep.com/patent/US20160257902A1

## CPC

- C10M 169/04: Mixtures of base-materials and additives
- C10M 105/34: of monocarboxylic acids
- C10M 107/10: containing aliphatic monomer having more than 4 carbon atoms
- C10M 129/72: of polycarboxylic acids
- C10M 145/14: Acrylate; Methacrylate
- C10M 2203/10: Petroleum or coal fractions, e.g. tars, solvents, bitumen
- C10M 2203/108: Residual fractions, e.g. bright stocks
- C10M 2205/022: Ethene
- C10M 2205/026: Butene
- C10M 2205/0285: used as base material
- C10M 2207/2805: used as base material
- C10M 2207/2815: used as base material
- C10M 2207/282: of (cyclo)aliphatic oolycarboxylic acids
- C10M 2207/2835: used as base material
- C10M 2209/084: Acrylate; Methacrylate
- C10M 2215/04: having amino groups bound to acyclic or cycloaliphatic carbon atoms
- C10M 2219/068: Thiocarbamate metal salts
- C10M 2223/04: Phosphate esters
- C10M 2223/041: Triaryl phosphates
- C10M 2223/043: Ammonium or amine salts thereof
- C10M 2229/02: Unspecified siloxanes; Silicones
- C10N 2020/02: Viscosity; Viscosity index
- C10N 2020/04: Molecular weight; Molecular weight distribution
- C10N 2030/10: Inhibition of oxidation, e.g. anti-oxidants
- C10N 2030/18: Anti-foaming property
- C10N 2040/04: Oil-bath; Gear-boxes; Automatic transmissions; Traction drives
- C10M: LUBRICATING COMPOSITIONS (well drilling compositions C09K8/02); USE OF CHEMICAL SUBSTANCES EITHER ALONE OR AS LUBRICATING INGREDIENTS IN A LUBRICATING COMPOSITION (mould release, i.e. separating, agents for metals B22C3/00, for plastics or substances in a plastic state, in general B29C33/56, for glass C03B40/02; textile lubricating compositions D06M11/00, D06M13/00, D06M15/00; immersion oils for microscopy G02B21/33)
- C10N: INDEXING SCHEME ASSOCIATED WITH SUBCLASS C10M RELATING TO LUBRICATING COMPOSITIONS

## Abstract

Provided is a lubricating oil composition containing (A) 70 mass % or more and 95 mass % or less of a poly-α-olefin base oil, (B) 5 mass % or more and 20 mass % or less of an ester-based base oil, and (C) an ester-based defoaming agent, the poly-α-olefin base oil (A) being a polymer of an α-olefin having 8 to 12 carbon atoms. The lubricating oil composition is able to keep excellent defoaming performance over a long period of time and is suitable as a step-up gear oil composition for wind power generation.

## Claims

### Claim 1

A lubricating oil composition, comprising
(A) 70 mass % or more and 95 mass % or less of a poly-α-olefin base oil,
(B) 5 mass % or more and 20 mass % or less of an ester-based base oil, and
(C) an ester-based defoaming agent,
wherein the poly-α-olefin base oil (A) is a polymer of an α-olefin comprising 8 to 12 carbon atoms.

### Claim 2 (depends on 1)

The lubricating oil composition according to claim 1, wherein a sum total of the poly-α-olefin base oil (A) and the ester-based base oil (B) is 90 mass % or more based on a total amount of the composition.

### Claim 3 (depends on 1)

The lubricating oil composition according to claim 1, wherein the ester-based defoaming agent (C) comprises a (meth)acrylate polymer having a weight average molecular weight of 10,000 or more and 100,000 or less.

### Claim 4 (depends on 1)

The lubricating oil composition according to claim 1, wherein the poly-α-olefin base oil (A) is a decene oligomer.

### Claim 5 (depends on 1)

The lubricating oil composition according to claim 1, wherein the ester-based base oil (B) is a polyol ester.

### Claim 6 (depends on 1)

The lubricating oil composition according to claim 1, which is a step-up gear oil composition for wind power generation.