| abstract |
A lubricating oil composition comprising a lubricating oil base oil, (A) a first antifoaming agent and a second antifoaming agent (B) a silicone-based antifoaming agent, the (A) first antifoaming agent being ( A1) the first polymer or (A2) the second polymer or their combination, (A1) the first polymer is a polymer with a first polymer chain and a second polymer chain, the first polymer chain comprises the general formula ( 1) Polysiloxane structure with a degree of polymerization of 5 to 2000, the second polymer chain contains repeating units represented by general formula (2) and is bonded to the first polymer chain, (A2) the second polymer is A copolymer of the first monomer component represented by the general formula (7) or (8) and the second monomer component represented by the general formula (9). [chemical 1] [Chem 2] [chemical 3] [Chem. 4] Q 8 -Z 8 -Y 8 (9). |