Lubricating oil composition containing an antifoaming agent

Abstract

Provided is a lubricating oil composition containing an antifoaming agent having high antifoaming performance even when the lubricant base oil has low viscosity. The lubricating oil composition comprises a lubricant base oil and drops of an antifoaming agent dispersion system dispersed in the lubricant base oil, wherein the antifoaming agent dispersion system comprises a dispersion medium mixture and an antifoaming agent dispersed in the dispersion medium mixture, and the dispersion medium mixture comprises a dispersion medium and an additive for dispersion.

1 . A lubricating oil composition comprising a lubricant base oil and an antifoaming agent contained in the lubricant base oil, wherein the lubricating oil composition comprises a lubricant base oil and drops of an antifoaming agent dispersion system dispersed in the lubricant base oil; the antifoaming agent dispersion system comprises a dispersion medium mixture and an antifoaming agent dispersed in the dispersion medium mixture; and the dispersion medium mixture comprises a dispersion medium and an additive for dispersion. 
     
     
         2 . The lubricating oil composition according to  claim 1 , wherein the antifoaming agent is fluoroalkylpolysiloxane. 
     
     
         3 . The lubricating oil composition according to  claim 1 , wherein the additive for dispersion is at least one selected from the group consisting of an ashless dispersant, a metallic detergent, an antiwear agent, a friction conditioner and an extreme pressure agent. 
     
     
         4 . The lubricating oil composition according to  claim 3 , wherein the ashless dispersant is selected from a succinimide compound, a succinamide compound and combinations thereof. 
     
     
         5 . The lubricating oil composition according to  claim 1 , wherein the dispersion medium mixture has a kinematic viscosity of 5-50,000 mm 2 /s at 40° C. 
     
     
         6 . The lubricating oil composition according to  claim 1 , wherein the dispersion medium is selected from a mineral oil, a synthetic oil and combinations thereof. 
     
     
         7 . The lubricating oil composition according to  claim 1 , wherein an antifoaming agent content in the lubricating oil composition is 0.01-500 ppm in terms of elemental fluorine (F) and 0.05-400 ppm in terms of elemental silicon (Si). 
     
     
         8 . The lubricating oil composition according to  claim 1 , which is for a transmission, for a gear, for gear oil, for a gear box, for an automotive gear box, for an industrial gear box, or for a transmission fluid. 
     
     
         9 . A method for manufacturing a lubricating oil composition comprising a lubricant base oil and an antifoaming agent contained in the lubricant base oil, comprising the steps of mixing a dispersion medium and an additive for dispersion to prepare a dispersion medium mixture; mixing an antifoaming agent with the dispersion medium mixture and dispersing the antifoaming agent in the dispersion medium mixture to prepare an antifoaming agent dispersion system; and then dispersing the antifoaming agent dispersion system in a lubricant base oil. 
     
     
         10 . The method for manufacturing a lubricating oil composition according to  claim 9 , wherein the antifoaming agent is fluoroalkylpolysiloxane. 
     
     
         11 . The method for manufacturing a lubricating oil composition according to  claim 9 , wherein the additive for dispersion is at least one selected from the group consisting of an ashless dispersant, a metallic detergent, an antiwear agent, a friction conditioner and an extreme pressure agent. 
     
     
         12 . The method for manufacturing a lubricating oil composition according to  claim 11 , wherein the ashless dispersant is selected from a succinimide compound, a succinamide compound and combinations thereof. 
     
     
         13 . The method for manufacturing a lubricating oil composition according to  claim 9 , wherein the dispersion medium mixture has a kinematic viscosity of 5-50,000 mm 2 /s at 40° C. 
     
     
         14 . The method for manufacturing a lubricating oil composition according to  claim 9 , wherein the dispersion medium is selected from a mineral oil, a synthetic oil and combinations thereof. 
     
     
         15 . The method for manufacturing a lubricating oil composition according to  claim 9 , wherein an antifoaming agent content in the lubricating oil composition is 0.01-500 ppm in terms of elemental fluorine (F) and 0.05-400 ppm in terms of elemental silicon (Si). 
     
     
         16 . The method for manufacturing a lubricating oil composition according to  claim 9 , wherein the lubricating oil composition is for a transmission, for a gear, for gear oil, for a gear box, for an automotive gear box, for an industrial gear box, or for a transmission fluid