Title:
VISCOSITY INDEX IMPROVER COMPOSITION AND LUBRICANT COMPOSITION
Document Type and Number:
Japanese Patent JP2016053154
Kind Code:
A
Abstract:
PROBLEM TO BE SOLVED: To provide a viscosity index improver excellent in shear stability of a lubricant composition, low in HTHS viscosity of the lubricant composition and hardly increasing low temperature viscosity of the lubricant composition.SOLUTION: There is provided a viscosity index improver composition containing (A) a (co)polymer having a (meth)acrylate monomer having a branched alkyl group having 10 or more carbon atoms as a constitutional unit and base oil and degree of branch (CB) of the branched alkyl group of the (meth)acrylate monomer derived from the following formula (1) and absolute value of difference of solubility parameter of (A) and solubility parameter of the base oil (ΔSP) satisfy the following formula (2) in the (co)polymer (A). (CB)=Σ[(BC)/(AC)×(BWT)]/(LCWT) (1). (CB)≤0.83×(ΔSP)-0.75 (2), where BC is the number of carbon atoms of a branched alkyl group side chain in each constitutional unit of the (meth)acrylate monomer, AC is the number of total carbon atoms constituting the branched alkyl group in each constitutional unit of the (meth)acrylate monomer, BWT is weight ratio (%) of each constitutional unit of the (meth)acrylate monomer based on weight of (A), LCWT is weight ratio (%) of total of each constitutional unit of the (meth)acrylate monomer based on weight of (A).SELECTED DRAWING: None
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Inventors:
NAKADA SHIGEKUNI
Application Number:
JP2015152707A
Publication Date:
April 14, 2016
Filing Date:
July 31, 2015
Export Citation:
Assignee:
SANYO CHEMICAL IND LTD
International Classes:
C10M145/14; C10M149/02
Domestic Patent References:
| JP2014141577A | 2014-08-07 | |||
| JP2004124080A | 2004-04-22 |