| 摘要 |
PROBLEM TO BE SOLVED: To provide a metal working oil having excellent lubricating performance, especially a water-soluble metal working oil, for metal working. SOLUTION: This metal working oil contains a copolymer comprising a vinyl lactam, anα-olefin and/or an alkyl (meth)acrylate as essential constitution units. As the vinyl lactam, N-vinyl pyrrolidone is especially favorable. |
