Patent ID: 8742149

Claim:
A water-insoluble cutting fluid base oil or grinding fluid base oil for metalworking comprising: a fatty acid polyoxyalkylene alkyl ether represented by the following formula (I-A), wherein a hydroxyl value of the fatty acid polyoxyalkylene alkyl ether is less than or equal to 2.0 mgKOH/g [Chem. 1] R 1 —CO-(OA) n -OR 3 (I-A) in the formula (I-A), R 1 represents a linear or branched, saturated or unsaturated monovalent hydrocarbon group having 15 to 21 carbon atoms and R 3 represents a linear, branched, or cyclic monovalent hydrocarbon group having 1 to 8 carbon atoms; in addition, A represents an alkylene group having 2 to 4 carbon atoms, OA represents alkylene oxide, and n represents 1 to 6 which is an average mole number of added alkylene oxide.