Lubricant composition comprising traction coefficient additive

Abstract

The present invention relates to a lubricant composition suitable for use in an electric vehicle. The lubricant composition comprises a traction coefficient additive and wherein the traction coefficient additive is an ester, said ester being the reaction product of at least one saturated branched-chain aliphatic monohydric alcohol having between 12 and 32 carbon atoms and at least one aliphatic carboxylic acid having between 6 and 32 carbon atoms. The lubricant composition as described herein provides an electric vehicle gear oil and imparts desirable coefficient of traction properties when in use.

1 - 29 . (canceled) 
     
     
         30 . A method of lubricating a gear box of an electric vehicle, comprising the step of lubricating the gear box with a gear oil including a base oil and a traction coefficient additive present in the gear oil in an amount effective to reduce a traction coefficient characteristic of the gear oil, wherein the traction coefficient additive comprises an ester, said ester being the reaction product of at least one saturated aliphatic carboxylic acid have 6 to 32 carbon atoms and a saturated, branched-chain, aliphatic monohydric alcohol having 12 to 24 carbon atoms. 
     
     
         31 . The method of  claim 30 , wherein the base oil comprises a mixture of two or more base oils selected from at least two different groups among Group I, Group II, Group III, and Group IV base oils. 
     
     
         32 . The method of  claim 30 , wherein the saturated, branched-chain, aliphatic monohydric alcohol is a Guerbet alcohol. 
     
     
         33 . The method of  claim 30 , wherein the saturated, branched-chain, aliphatic monohydric alcohol is selected from the group consisting of a C12 Guerbet alcohol, a C14 Guerbet alcohol, a C16 Guerbet alcohol, a C18 Guerbet alcohol, a C20 Guerbet alcohol, and a C24 Guerbet alcohol 
     
     
         34 . The method of  claim 30 , wherein the saturated, branched-chain, aliphatic monohydric alcohol comprises a main carbon chain that is branched at the beta carbon position of the main carbon chain. 
     
     
         35 . The method of  claim 30 , wherein the saturated, branched-chain, aliphatic monohydric alcohol is 2-octyldodecanol. 
     
     
         36 . The method of  claim 30 , wherein the saturated, branched-chain, aliphatic monohydric alcohol is 2-butyloctanol. 
     
     
         37 . The method of  claim 30 , wherein the saturated, branched-chain, aliphatic monohydric alcohol is 
     
     
         38 . The method of  claim 30 , wherein the saturated aliphatic carboxylic acid is linear. 
     
     
         39 . The method of  claim 30 , wherein the saturated aliphatic carboxylic acid is branched. 
     
     
         40 . The method of  claim 30 , wherein the ester is a heptanoate ester. 
     
     
         41 . The method of  claim 30 , wherein the ester is a stearate ester. 
     
     
         42 . The method of  claim 30 , wherein the ester is a di-sebacate ester. 
     
     
         43 . The method of  claim 30 , wherein the ester is an isostearate ester. 
     
     
         44 . The method of  claim 30 , wherein the ester is 2-octyldodecyl isooctadecanoate. 
     
     
         45 . The method of  claim 30 , wherein the ester is 2-hexyldecyl heptanoate. 
     
     
         46 . The method of  claim 30 , wherein the ester is 2-butyloctyl octadecenoate. 
     
     
         47 . The method of  claim 30 , wherein the ester is bis(2-butyloctyl) decanedioate. 
     
     
         48 . The method of  claim 30 , wherein the ester is 2-octyldodecyl isooctadecanoate. 
     
     
         49 . The method of  claim 30 , wherein the ester is 2-octyldodecyl heptanoate. 
     
     
         50 . The method of  claim 30 , wherein the gear oil includes 3 wt % to 25 wt % of the traction coefficient additive. 
     
     
         51 . The method of  claim 30 , wherein the gear oil includes up to 50 wt % of the traction coefficient additive. 
     
     
         52 . The method of  claim 30 , wherein the gear oil includes up to 35 wt % of the traction coefficient additive. 
     
     
         53 . The method of  claim 30 , wherein the gear oil includes at least 3 wt % of the traction coefficient additive. 
     
     
         54 . An electric vehicle comprising a gear box lubricated with a gear oil including a base oil and a traction coefficient additive present in the gear oil in an amount effective to reduce a traction coefficient characteristic of the gear oil, wherein the traction coefficient additive comprises an ester, said ester being the reaction product of at least one saturated aliphatic carboxylic acid have 6 to 32 carbon atoms and a saturated, branched-chain, aliphatic monohydric alcohol having 12 to 24 carbon atoms.