| 摘要 |
<P>PROBLEM TO BE SOLVED: To provide a hydraulic fluid composition exhibiting low temporary shearing viscosity under a high shearing condition and having excellent permanent shearing stability and a low coefficient of friction. <P>SOLUTION: The industrial hydraulic fluid composition is a composition comprising: (A) a hydrocarbon lubricant base oil having 40°C kinematic viscosity of 10-40 mm<SP POS="POST">2</SP>/s; and (B) an ester polymer, wherein the ester polymer is formed by condensation polymerization of a half ester that is a reactant of polyhydric alcohol with a monocarboxylic acid, with a dicarboxylic acid; a weight average molecular weight is 10,000-200,000; an ester value is 50-300 mgKOH/g; and the kinematic viscosity of the composition at 40°C is 19-51 mm<SP POS="POST">2</SP>/s. <P>COPYRIGHT: (C)2012,JPO&INPIT |
