Dual phase lubricants

Abstract

Implementations of the disclosed subject matter provide a lubricating oil composition. The composition comprising (a) from 45 to 75 mass % of a low viscosity first base oil component which is a Fischer-Tropsch derived base oil with a kinematic viscosity at 100° C. in the range of from 3.5 to 7.0 mm 2 /s; (b) from 3 to 35 mass % of a high viscosity second base oil component which is a polyalkylene glycol; and (c) an anti-foam additive which is a non-ionic surfactant. The mass % of the composition is based on the overall mass of the lubricating composition.

1 . A lubricating oil composition comprising:
 (a) from 45 to 75 mass % of a low viscosity first base oil component which is a Fischer-Tropsch derived base oil with a kinematic viscosity at 100° C. in the range of from 3.5 to 7.0 mm 2 /s;   (b) from 3 to 35 mass % of a high viscosity second base oil component which is a polyalkylene glycol;   (c) an anti-foam additive which is a non-ionic surfactant,   wherein mass % is based on the overall mass of the lubricating composition.   
     
     
         2 . A lubricating oil composition according to  claim 1 , wherein the low viscosity first base oil component has a kinematic viscosity at 100° C. in the range of from 4.0 to 6.0 mm 2 /s. 
     
     
         3 . A lubricating oil composition according to  claim 1 , wherein the high viscosity second base oil component has a kinematic viscosity at 100° C. in the range of from 90 to 120 mm 2 /s, preferably 95 to 105 mm 2 /s. 
     
     
         4 . A lubricating oil composition according to  claim 1 , which also comprises a control component, which comprises one or more ester base oils. 
     
     
         5 . A lubricating oil composition according to  claim 4 , wherein the ester base oils have an oxygen/carbon weight ratio of from 0.080 to 0.350, preferably from 0.080 to 0.300. 
     
     
         6 . A lubricating oil composition according to  claim 4 , wherein the ester base oils have a kinematic viscosity at 100° C. of no more than 1 mm 2 /s, more preferably no more than 0.5 mm 2 /s, above or below that of the low viscosity first base oil component. 
     
     
         7 . A lubricating oil composition according to  claim 4 , wherein the control component, which comprises one or more ester base oils is present in an amount of from 2 to 10 mass %, based on the overall mass of the lubricating oil composition. 
     
     
         8 . A lubricating oil composition as claimed in  claim 1 , wherein the non-ionic surfactant is selected from poly-alkoxylated alcohols, poly-alkoxylated amines and mixtures thereof. 
     
     
         9 . A method for lubricating an axle, said method comprising supplying to said axle a lubricating oil composition comprising:
 (a) from 45 to 75 mass % of a low viscosity first base oil component which is a Fischer-Tropsch derived base oil with a kinematic viscosity at 100° C. in the range of from 3.5 to 7.0 mm 2 /s;   (b) from 3 to 35 mass % of a high viscosity second base oil component which is a polyalkylene glycol;   (c) an anti-foam additive which is a non-ionic surfactant,   wherein mass % is based on the overall mass of the lubricating composition.