Patent ID: 8227387

Claim:
A metalworking oil composition comprising: a lubricating base oil having % C A of not more than 2, % C P /% C N of not less than 6, % C N of 7 to 13, a sulfur content of not more than 100 ppm by mass, and an iodine value of not more than 2.5, wherein the content of the saturated components in the lubricating base oil is not less than 95% by mass based on the total amount of the lubricating base oil and wherein the ratio M A /M B of the mass of monocyclic saturated components M A to the mass of bi- or more cyclic saturated components M B in the saturated cyclic components is not more than 3; and at least one lubricity improver selected from esters of a monohydric alcohol and a monobasic acid, esters of a polyhydric alcohol and a polybasic acid, mixed esters of a mixture of a monohydric alcohol and a polyhydric alcohol, and a polybasic acid, mixed esters of a polyhydric alcohol and a mixture of a monobasic acid and a polybasic acid, mixed ester of a mixture of a monohydric alcohol and a polyhydric alcohol, and a monobasic acid and a polybasic acid, carboxylic acids, phosphoric acid esters, acidic phosphoric acid esters, amine salts of acidic phosphoric acid esters, chlorinated phosphoric acid esters, sulfurized oils and fats, sulfurized fatty acids, sulfurized esters, dihydrocarbyl (poly)sulfides, thiadiazole compounds, thioterpene compounds, dialkyl-thiodipropionate compounds and sulfurized mineral oils.