Use of lubricants with carboxylic acid esters in electric vehicles

Abstract

The present invention relates to a use of a lubricant comprising a base oil selected from a carboxylic acid ester in an electric vehicle. It further relates to a method for lubricating an electric vehicle with a lubricant comprising the carboxylic acid ester.

1 .- 15 . (canceled) 
     
     
         16 . A use of a lubricant comprising a base oil selected from a carboxylic acid ester in an electric vehicle. 
     
     
         17 . The use according to  claim 16  where the electric vehicle comprises a rotary electric machine and an electric power storage device configured to store electric power that is used to drive the rotary electric machine. 
     
     
         18 . The use according to  claim 16  where the lubricant is present within the rotary electric machine of the electric vehicle. 
     
     
         19 . The use according to  claim 16  where the lubricant is present outside the rotary electric machine in direct contact with it or within a distance of up to 50 cm. 
     
     
         20 . The use according to  claim 16  where the carboxylic acid ester has a electrical conductivity from 0.1 to 100 000 pS/m. 
     
     
         21 . The use according to  claim 16  where the carboxylic acid ester has a heat conductivity of at least 0.120 W/mK. 
     
     
         22 . The use according to  claim 16  where the carboxylic acid ester has a thermo-oxidative stability determined by high pressure differential scanning calorimetry of at least 130° C. onset temperature. 
     
     
         23 . The use according to  claim 16  where the carboxylic acid ester is a monoester, diester, polyester, complex ester, or mixture thereof. 
     
     
         24 . The use according to  claim 16  where the carboxylic acid ester is obtainable by reacting
 (i) at least one linear or branched C 2 -C 24  monocarboxylic acid with at least one linear or branched C 1 -C 20  monoalcohol (also called “monoester”) or; 
 (ii) at least one linear or branched C 2 -C 20  dicarboxylic acid with at least one linear or branched C 1 -C 20  monoalcohol (also called “diester”) or; 
 (iii) at least one linear or branched C 2 -C 24  monocarboxylic acid with at least one C 2 -C 20  polyol having 2-10 hydroxyl group (also called “polyester”) or; 
 (iv) a mixture comprising at least one linear or branched C 2 -C 24  monocarboxylic acid and at least one linear or branched C 2 -C 20  dicarboxylic acid and at least one C 2 -C 20  polyol having 2-10 hydroxyl group (also called “complex ester”). 
 
     
     
         25 . The use according to  claim 16  where the carboxylic acid ester is a diester obtainable by reacting
 at least one linear or branched C 3 -C 12  dicarboxylic acid selected from the group consisting of malonic acid, succinic acid, glutaric acid, adipic acid, maleic acid, fumaric acid, azelaic acid, sebacic acid, brassilic acid, docdecanedioic acid, diglycolic acid, 1,4-cyclohexanedicarboxylic acid, 1,3-cyclohexanedicarboxylic acid and 2,6-decahydro-naphthalenedicarboxylic acid with 
 at least one branched C 5 -C 14  monoalcohol selected from the group consisting of pentanol, hexanol, heptanol, iso-pentanol, iso-hexanol, iso-heptanol, 2-ethylhexanol, 2-propylheptanol, 2-propyl-4-methyl-hexanol, 2-propyl-5-methyl-hexanol, 2-isopropyl-4-methyl-hexanol, 2-isopropyl-5-methyl-hexanol, 2-propyl-4,4-dimethylpentanol, 2-ethyl-2,4-dimethylhexanol, 2-ethyl-2-methyl-heptanol, 2-ethyl-2,5-dimethylhexanol, 2-isopropyl-heptanol, 2-butyl-1-octanol and 2-pentyl-1-nonanol. 
 
     
     
         26 . The use according to  claim 16  where the carboxylic acid ester is a polyester obtainable by reacting
 at least one linear or branched C 5 -C 18  monocarboxylic acid selected from the group consisting of pentanoic acid, caproic acid, heptanoic acid, caprylic acid, nonanoic acid capric acid, undecanoic acid, dodecanoic acid, tridecanoic acid, tetradecanoic acid, pentadecanoic acid, hexadecanoic acid, heptadecanoic acid, octadecanoic acid, oleic acid, palmitoleic acid with 
 at least one C 2 -C 20  polyol having 2-10 hydroxyl group selected from the group consisting of ethylene glycol, 1,2-propylene glycol, 1,3-propylene glycol, 1,2-butylene glycol, 1,3-butylene glycol, 2,3-butylene glycol, neopentyl glycol, trimethylol propane, trimethylol ethane, pentaerythritol, sorbitol, and dipentaerythritol. 
 
     
     
         27 . The use according to  claim 16  where the carboxylic acid ester is a complex ester obtainable by reacting a mixture comprising
 at least one linear or branched C 5 -C 18  monocarboxylic acid selected from the group consisting of pentanoic acid, caproic acid, heptanoic acid, caprylic acid, nonanoic acid capric acid, undecanoic acid, dodecanoic acid, tridecanoic acid, tetradecanoic acid, pentadecanoic acid, hexadecanoic acid, heptadecanoic acid, octadecanoic acid, oleic acid, palmitoleic acid and 
 at least one linear or branched C 3 -C 10  dicarboxylic acid selected from the group consisting of malonic acid, succinic acid, glutaric acid, adipic acid, heptanedioic acid, octananedioic acid, nonanedioic acid, decanedioic acid and 
 at least one C 2 -C 20  polyol having 2-10 hydroxyl group selected from the group consisting of ethylene glycol, 1,2-propylene glycol, 1,3-propylene glycol, 1,2-butylene glycol, 1,3-butylene glycol, 2,3-butylene glycol neopentyl glycol, trimethylol propane, trimethylol ethane, pentaerythritol, sorbitol, and dipentaerythritol. 
 
     
     
         28 . The use according to  claim 16  where the lubricant comprises at least 10 wt. % of the carboxylic acid ester. 
     
     
         29 . A method comprising lubricating an electric vehicle with a lubricant comprising a base oil selected from a carboxylic acid ester.