Transmission oil composition for automobile

Abstract

A transmission oil composition for an automobile characterized in that it contains a base oil selected from the group consisting of a mineral oil, a synthetic oil and mixtures thereof; and a phosphate compound selected from the group consisting of (A) a zinc dithiophosphate having a hydrocarbon group, (B) a triaryl phosphate (C) a triaryl thiophosphate, and mixtures thereof at 0.1 to 15.0% by mass with respect to the total composition; wherein the composition has a volume resistivity of 1×10 7 ohm·m or more at 80° C.

1 . A transmission oil composition for an automobile comprising: 
 a base oil consisting essentially of a mineral oil having a kinematic viscosity at 80° C. of 1.5 to 8.0 mm 2 /s and a viscosity index of 80 or more; and    a phosphate compound selected from the group consisting of (A) a zinc dithiophosphate having a hydrocarbon group, (B) a triaryl phosphate, (C) a triaryl thiophosphate, and mixtures thereof at 0.1 to 15.0% by mass with respect to the total composition;    wherein said composition has volume resistivity of 1×10 7  ohm·m or more at 80° C., and    wherein the kinematic viscosity of said composition at 80° C. is 1.5 to 15 mm 2 /s.    
     
     
         2 . The transmission oil composition for the automobile of  claim 1  requisitely comprising as said phosphate compound a phosphate compound selected from the group consisting of (A) a zinc dithiophosphate having a hydrocarbon group, (C) a triaryl thiophosphate, and mixtures thereof  
     
     
         3 . The transmission oil composition for the automobile of  claim 1  further comprising (D) an ashless dispersant.  
     
     
         4 . (canceled)  
     
     
         5 . The transmission oil composition for the automobile of  claim 1  wherein the volume resistivity of said composition at 80° C. is 5×10 8  ohm·m or more.  
     
     
         6 . (canceled)  
     
     
         7 . The transmission oil composition for the automobile of  claim 1  wherein said composition is an oil for a transmission system, an oil for both the transmission system and an electric motor, or an oil for a device in which the transmission system and the electric motor share a common lubrication system in an electric vehicle or a hybrid vehicle.  
     
     
         8 . A transmission oil composition for an automobile comprising: 
 a base oil consisting essentially of a synthetic oil selected from the group consisting of 1-octene oligomer, a hydride thereof, 1-decene oligomer, a hydride thereof, ethylenepropylene oligomer, a hydride thereof, di-tridecyl glutarate, di-2-ethylhexyl adipate, di-isodecyl adipate, di-tridecyl adipate, di-2-ethylhexyl sebacate, trimethylolpropane caprylate, trimethylolpropane pelargonate, pentaerythritol 2-ethylhexanoate, pentaerythritol pelargonate, neopentyl glycol 2-ethylhexanoate, and mixtures thereof, and    a phosphate compound selected from the group consisting of (A) a zinc dithiophosphate having a hydrocarbon group, (B) a triaryl phosphate, (C) a triaryl thiophosphate, and mixtures thereof at 0.1 to 15.0% by mass with respect to the total composition,    wherein said composition has volume resistivity of 1×10 7  ohm·m or more at 80° C., and    wherein the kinematic viscosity of said composition at 80° C. is 1.5 to 4.0 mm 2 /s.    
     
     
         9 . The transmission oil composition for the automobile of  claim 8  requisitely comprising as said phosphate compound a phosphate compound selected from the group consisting of (B) a triaryl phosphate, (C) a triaryl thiophosphate, and mixtures thereof.  
     
     
         10 . The transmission oil composition for the automobile of  claim 8  requisitely comprising as said phosphate compound a phosphate compound selected from the group consisting of (A) a zinc dithiophosphate having a hydrocarbon group, (C) a triaryl thiophosphate, and mixtures thereof.  
     
     
         11 . The transmission oil composition for the automobile of  claim 8  further comprising (D) an ashless dispersant.  
     
     
         12 . The transmission oil composition for the automobile of  claim 8  wherein the volume resistivity of said composition at 80° C. is 5×10 8  ohm·m or more.  
     
     
         13 . The transmission oil composition for the automobile of  claim 8  wherein said composition is an oil for a transmission system, an oil for both the transmission system and an electric motor, or an oil for a device in which the transmission system and the electric motor share a common lubrication system in an electric vehicle or a hybrid vehicle.