Lubricant composition

Patent metadata

Field	Value
Publication number	US-9447359-B2
Application number	US-81252409-A
Country	US
Kind code	B2
Filing date	Jan 9, 2009
Priority date	Jan 15, 2008
Publication date	Sep 20, 2016
Grant date	Sep 20, 2016

Abstract

The invention provides a lubricating oil composition comprising:
a lubricating base oil having a kinematic viscosity at 100° C. of 1-10 mm 2 /s, a % C p of 70 or greater and a % C A of not greater than 2; a first viscosity index improver of 0.01-10% by mass, based on the total weight of the composition, wherein the first viscosity index improver is a poly(meth)acrylate having a weight-average molecular weight of not greater than 100,000; and a second viscosity index improver of 0.01-50% by mass, based on the total weight of the composition, wherein the second viscosity index improver is a polymer having a weight-average molecular weight of 100,000 or greater and containing a structural unit represented by the following formula (1) in a proportion of 0.5-70 mol %, the composition having a kinematic viscosity at 100° C. of 4-12 mm 2 /s and a viscosity index of 140-300.

wherein R 1 represents hydrogen or a methyl group and R 2 represents a C16 or greater straight-chain or branched hydrocarbon, or an oxygen- and/or nitrogen-containing C16 or greater straight-chain or branched organic group.

First claim

The invention claimed is:

1. A lubricating oil composition comprising:
a lubricating base oil having a kinematic viscosity at 100° C. of 1-10 mm 2 /s, a viscosity index of 120 or greater, a % C p of 80 or greater and a % C A of not greater than 0.5;
a first viscosity index improver of 0.1-3% by mass, based on the total weight of the composition, wherein the first viscosity index improver is a poly(meth)acrylate having a weight-average molecular weight of not greater than 100,000; and
a second viscosity index improver of 5-20% by mass, based on the total weight of the composition, wherein the second viscosity index improver
has a PSSI of no greater than 40 and a ratio of weight-average molecular weight/PSSI of at least 1×10 4 , and
is a polymer having a weight-average molecular weight of 100,000 or greater and containing a structural unit represented by the following formula (1) in a proportion of 0.5-70 mol % and methyl methacrylate,

wherein R 1 represents hydrogen or a methyl group and R 2 represents a C22 or greater straight-chain or branched hydrocarbon, or an oxygen- and/or nitrogen-containing C22 or greater straight-chain or branched organic group,
the composition having a kinematic viscosity at 100° C. of 4-12 mm 2 /s and a viscosity index of 140-300.

2. The lubricating oil composition according to claim 1 , wherein the first viscosity index improver is a (meth)acrylate copolymer containing a C1-18 hydrocarbon group.

3. A lubricating oil composition according to claim 1 , wherein the second viscosity index improver is a dispersant poly(meth)acrylate-based viscosity index improver.

4. The lubricating oil composition according to claim 1 , wherein the second viscosity index improver contains a C22 or greater branched hydrocarbon group as R 2 in the formula (1).

5. The lubricating oil composition according to claim 1 , further comprising at least one friction modifier selected from among organic molybdenum compounds and ash-free friction modifiers.

Assignees

• Matsui Shigeki
• Yaguchi Akira
• Jx Nippon Oil & Energy Corp

Inventors

• Matsui Shigeki
• Yaguchi Akira

Classifications

• C10N2020/04

  Molecular weight; Molecular weight distribution · CPC title

• C10M2203/1025

  used as base material · CPC title

• C10M2219/068

  Thiocarbamate metal salts · CPC title

• C10N2030/02

  Pour-point; Viscosity index · CPC title

• C10M2209/084

  Acrylate; Methacrylate · CPC title