Patent ID: 7927503

Claim:
A lubricating oil, comprising a polyvinyl ether compound containing an alkylene glycol or polyoxyalkylene glycol unit and a vinyl ether unit in a molecule and having a molecular weight in a range of 300 to 3,000, wherein said polyvinyl ether compound is a compound of formula (I): wherein R 1 , R 2 , and R 3 each represent a hydrogen atom or a hydrocarbon group having 1 to 8 carbon atoms, which may be identical to or different from one another; R b represents a divalent hydrocarbon group having 2 to 4 carbon atoms; R a represents a hydrogen atom, an aliphatic or alicyclic hydrocarbon group having 1 to 20 carbon atoms, an aromatic group which has 1 to 20 carbon atoms and may have a substituent, an acyl group having 2 to 20 carbon atoms, or an oxygen-containing hydrocarbon group having 2 to 50 carbon atoms; R 4 represents a hydrocarbon group having 1 to 10 carbon atoms; when there are two or more of each of R a , R b , and R 4 , they may be identical to or different from one another; m represents an average value of 2 to 50; k represents an average value of 1 to 50; p represents an average value of 2 to 25; when k and p each represent 2 or more, constitutional units may be in block or in random; and when there are two or more of R b O, they may be identical to or different from one another; and wherein the polyvinyl ether compound has a carbon/oxygen molar ratio of 4.0 or less.