Lubricating oil composition

Abstract

A lubricating oil composition may have excellent long-term anti-foaming performance and detergency while blending a silicone-based anti-foaming agent. Such a lubricating oil composition may contain a base oil (A) and a silicone-based anti-foaming agent (B). A silicon atom content may be 50 ppb by mass to 4,000 ppb by mass, based on a total amount of the lubricating oil composition.

1 . A lubricating oil composition, comprising:
 a base oil (A); and   a silicone-based anti-foaming agent (B),   wherein a silicon atom content is 50 ppb by mass to 4,000 ppb by mass based on a total amount of the lubricating oil composition.   
     
     
         2 . The composition of  claim 1 , wherein the base oil (A) is one or more selected from the group consisting of a synthetic oil (A1) and a mineral oil (A2). 
     
     
         3 . The composition of  claim 1 , wherein the base oil (A) is two or more selected from the group consisting of a synthetic oil (A1) and a mineral oil (A2). 
     
     
         4 . The composition of  claim 1 , wherein the base oil (A) is two or more selected from the group consisting of a synthetic oil (A1) and a mineral oil (A2) and having different kinematic viscosities at 40° C. 
     
     
         5 . The composition of  claim 1 , wherein a total content of the base oil (A) and the silicone-based anti-foaming agent (B) is 75% by mass or more and 94.9% by mass or less based on the total amount of the lubricating oil composition. 
     
     
         6 . The composition of  claim 1 , wherein the silicone-based anti-foaming agent (B) comprises one or more selected from the group consisting of polydimethylsiloxane and fluorinated polysiloxane. 
     
     
         7 . The composition of  claim 1 , further comprising:
 one or more lubricating oil additives selected from the group consisting of an antioxidant, an extreme pressure agent, an anti-emulsifier, a rust inhibitor, a viscosity index improver, a pour point depressant, a metal deactivator, an ash-free detergent dispersant, and a friction modifier.   
     
     
         8 . The composition of  claim 1 , which is suitable for an accelerator oil for a wind turbine, a hydraulic oil, a compressor oil, a gear oil, a cutting oil, a machine tool oil, a refrigerator oil, a turbine oil, an internal combustion engine oil, a transmission oil, or an axle unit oil for a vehicle.