Poly(meth)acrylate-based viscosity index improver, lubricant additive and lubricant composition containing viscosity index improver

• US 9,783,757 B2
• Filed: 07/24/2013
• Issued: 10/10/2017
• Est. Priority Date: 07/24/2012
• Status: Active Grant

• Current Assignee: ENEOS Corporation (ENEOS Holdings, Inc.)
• Original Assignee: JX Nippon Oil & Energy Corporation (ENEOS Holdings, Inc.)
• Inventors: Matsui, Shigeki, Miyamoto, Hiroya, Matsuda, Hiromitsu, Tagawa, Kazuo, Takagi, Akira, Ueno, Ryuichi
• Primary Examiner(s): WEISS, PAMELA HL
• Application Number:
  US14/413,573
• Publication Number:
  US 20150203781A1
• Time in Patent Office: 1,539 Days
• CPC Class Codes: C10M 145/14 Acrylate; Methacrylate
• CPC Class Codes: C10M 2203/1025 used as base material
• CPC Class Codes: C10M 2207/289 containing free hydroxy groups
• CPC Class Codes: C10M 2209/084 Acrylate; Methacrylate
• CPC Class Codes: C10M 2215/064 Di- and triaryl amines
• CPC Class Codes: C10M 2215/28 Amides; Imides
• CPC Class Codes: C10M 2219/024 of esters, e.g. fats
• CPC Class Codes: C10M 2219/046 Overbasedsulfonic acid salts
• CPC Class Codes: C10M 2219/106 Thiadiazoles
• CPC Class Codes: C10M 2223/04 Phosphate esters
• CPC Class Codes: C10M 2223/045 Metal containing thio derivatives
• CPC Class Codes: C10N 2010/04 Groups 2 or 12
• CPC Class Codes: C10N 2020/02 Viscosity; Viscosity index
• CPC Class Codes: C10N 2020/04 Molecular weight; Molecular weight distribution
• CPC Class Codes: C10N 2020/073 Star shaped polymers
• CPC Class Codes: C10N 2030/02 Pour-point; Viscosity index
• CPC Class Codes: C10N 2030/06 Oiliness; Film-strength; Anti-wear; Resistance to extreme pressure
• CPC Class Codes: C10N 2030/54 Fuel economy
• CPC Class Codes: C10N 2030/68 Shear stability
• CPC Class Codes: C10N 2040/042 for automatic transmissions
• CPC Class Codes: C10N 2040/044 : for manual transmissions
• CPC Class Codes: C10N 2040/045 : for continuous variable transmission [CVT]
• CPC Class Codes: C10N 2040/25 : Internal-combustion engines

Abstract

The present invention provides a poly(meth)acrylate-based viscosity index improver comprising a core portion and three or more arm portions, wherein each of the arm portions consists of a polymer chain comprising a structural unit represented by the following formula (1), and one end of the polymer chain is bonded to the core portion, and wherein a weight-average molecular weight Mw is 100000 or more, and a ratio of the weight-average molecular weight Mw to a number average molecular weight Mn, Mw/Mn, is 1.6 or less.

[R¹ represents hydrogen or a methyl group, and R² represents a C1 to C36 alkyl group.]

Claims

1. A lubricating oil composition comprising:

a lubricating base oil; and

a poly(meth)acrylate-based viscosity index improver comprising;

a core portion derived from a compound having three or more functional groups that react with a carbon-carbon double bond of an acryloyl group chosen from the group consisting of 1,1,1-tris(2-bromoisobutyloxymethylene)ethane, pentaerythritoltetrakis(2-bromoisobutyrate), and dipentaerythritolhexakis(2-bromoisobutyrate); and

three or more arm portions,

wherein each of the arm portions consists of a polymer chain consisting of structural units represented by formula (1) shown below, and one end of the polymer chain is bonded to the core portion,

2. The lubricating oil composition according to claim 1, wherein the weight-average molecular weight, Mw, of the poly(meth)acrylate-based viscosity index improver is 100000 or more.

3. The lubricating oil composition according to claim 1, wherein the weight-average molecular weight, Mw, of the poly(meth)acrylate-based viscosity index improver is less than 100000.