| abstract |
A coolant composition includes: a viscosity improving agent; at least one alkali metal compound selected from the group consisting of alkali metal salts and alkali metal hydroxides; and a base composed of water and/or at least one alcohol selected from the group consisting of a monohydric alcohol, a dihydric alcohol, a trihydric alcohol, and a glycol monoalkyl ether, wherein the viscosity improving agent is a compound represented by a formula of R1O-(R2O)m-SO3M, where R1 represents a linear or branched alkyl or alkenyl group having 16 to 24 carbon atoms, R2 represents an ethylene group or a propylene group, m represents an average addition molar number of R2O and a number from 0.5 to 10, and M represents a cation or a hydrogen atom, and a kinetic viscosity of the coolant composition is 8.5 mm2/sec or higher at 25°C and is 2.0 mm2/sec or lower at 100°C. |