| 摘要 |
PURPOSE:To provide a lubricating oil composition containing a defoamer which prevents foaming when the composition is used at a low viscosity as refrigerator oil, prepared by adding trifluoropropylmethylpolysiloxane to a base oil consisting of a specified synthetic oil. CONSTITUTION:The lubricating oil composition is prepared by adding 0.1- 30ppm trifluoropropylmethylpolysiloxane to a base synthetic oil consisting of paraffinic, nephthenic or mixed mineral oil and olefin and having a viscosity of 3-15cSt at 40 deg.C. Dimethylpolysiloxane having a viscosity of 1X10<3>-1X10<4>cSt has so far been used as defoamer for refrigerator oil, but as the viscosity of the refrigerator oil is reduced, it becomes highly soluble in the oil and loses its foaming preventive power. The trifluoropropylmethylpolysiloxane shows an excellent foaming preventive effect in a state in which the siloxane molecules are incorporated into the refrigerator oil, as foams disappear through destruction of a part of intermolecular force of a hydrocarbon which constitutes the refrigerator oil. |
