Blends of lubricant basestocks with polyol esters

Abstract

A lubricating composition is provided comprising a polyol ester which is the reaction product of a neopolyol with linear or branched monocarboxylic acids and mixtures thereof having from 1 to about 25 carbon atoms and a natural or GTL oil of lubricating viscosity and mixtures thereof and wherein the weight ratio of the ester to oil will be sufficient to provide a composition having a viscosity less than the individual viscosities of the ester and oil.

1 . A lubricating composition comprising:
 a polyol ester which is the reaction product of a neopolyol with linear or branched monocarboxylic acids, and mixtures thereof having from 1 to about 25 carbon atoms and a natural or GTL oil of lubricating viscosity and mixtures thereof;   the weight ratio of ester to oil being a ratio sufficient to provide a composition having a kinematic viscosity at 100° C. that is less than the kinematic viscosity at 100° C. of each of the oil and ester.   
   
   
       2 . The composition of  claim 1  wherein the ester has from 0 up to about 1 free hydroxyl groups. 
   
   
       3 . The composition of  claim 1  wherein the weight ratio of ester to natural or GTL ratio is between 20:80 to 80:20. 
   
   
       4 . The composition of  claim 2  wherein the neopolyol is selected from the group consisting of neopentylglycol, trimethylolpropane, monopentaerythritol, technical grade pentaerythritol, and dipentaerythritol. 
   
   
       5 . The composition of  claim 4  wherein the monocarboxylic acid is a mixture of acids. 
   
   
       6 . The composition of  claim 5  wherein the natural oil of lubricating viscosity is a mineral oil. 
   
   
       7 . The composition of  claim 6  wherein the ester and mineral oil have substantially the same kinematic viscosity at 100° C. 
   
   
       8 . The composition of  claim 7  wherein the mineral oil is a blend of mineral oils. 
   
   
       9 . The composition of  claim 1  wherein the oil of lubricating viscosity is a GTL oil. 
   
   
       10 . The composition of  claim 9  wherein the polyol ester has substantially no free hydroxyl groups. 
   
   
       11 . The composition of  claim 9  wherein the neopolyol is pentaerythritol, and the monocarboxylic acids are a mixture of acids. 
   
   
       12 . The composition of  claim 1 ,  8 , and  11  including at least one additive selected from the group consisting of antioxidants, dispersants, detergents, antiwear agents, pour point depressants, friction modifiers, viscosity modifiers and antifoamants. 
   
   
       13 . A method for improving the efficiency of an internal combustion engine lubricated with a lubricating oil composition comprising a natural or GTL base oil, the method comprising providing the base oil with a polyol ester of a neopolyol with linear or branched monocarboxylic acids and mixtures thereof having from 1 to about 25 carbon atoms in an amount sufficient to provide a composition having a kinematic viscosity at 100° C. that is less than the kinematic viscosity at 100° C. of each of the oil and ester. 
   
   
       14 . The method of  claim 13  wherein the ester has from 0 up to about 1 free hydroxyl group per molecule. 
   
   
       15 . The method of  claim 14  wherein the oil is a natural mineral oil. 
   
   
       16 . The method of  claim 14  wherein the oil is a GTL oil.