Ashless lubricant composition

Abstract

A lubricant composition with improved antioxidant capability is provided by way of an additive composition containing a metal free sulfur-containing compound, an aromatic amine, and a hindered amine. Particularly effective metal-free sulfur-containing compounds include ashless dithiocarbamates, such as methylenebis(dibutyldithiocarbamate), and sulfurized fatty acids.

1 - 16 . (canceled) 
     
     
         17 . A lubricating composition comprising at least 90% by weight of a lubricant basestock, and about 0.5-5% by weight of an antioxidant additive composition comprising:
 (a) an ashless dithiocarbamate;   (b) a hindered amine being one or more chosen from the group consisting of:   (1) a compound of the formula   
       
         
           
           
               
               
           
         
         where R 26  is H, O or a hydrocarbon from 1 to 25 carbon atoms, an alkoxy radical with the oxygen bound to the nitrogen with the alkyl portion containing 1 to 25 carbon atoms, or a COR group, the R being a hydrocarbon containing from 1 to 25 carbon atoms; R 27 , R 28 , R 32 , R 33  are hydrocarbons with 1 to 25 carbon atoms; R 29 , R 31  are H or hydrocarbons with 1 to 25 carbon atoms; when n=1, R 30  is OH, H, O, NH 2 , NR 2  where R is a hydrocarbon with 1 to 25 carbon atoms, an ester group O 2 CR where R is a hydrocarbon with 1 to 25 carbon atoms, or a succinimide group; when n=2, R 30  is the diacyl radical of an aliphatic dicarboxylic acid having 4 to 12 carbon atoms; 
         (2) 4-stearoyloxy-2,2,6,6-tetramethylpiperidine, 
         (3) di(2,2,6,6-tetramethylpiperidin-4-yl) sebacate, 
         (4) di(1,2,2,6,6-pentamethylpiperidin-4-yl) sebacate, 
         (5) bis (1-octyloxy-2,2,6, -tetramethyl-4-piperidyl) sebacate 
         (6) polymer-bound piperidine compound, 
         (7) a compound of the group consisting of 2,2,6,6-tetramethylpiperidines, 1,2,2,6,6-pentamethylpiperidines, 1-oxo-2,2,6,6-tetramethylpiperidines, and 1-alkoxy-2,2,6,6-tetramethylpiperidines, and 
         (8) a compound of the group consisting of di(1,2,2,6,6-pentamethylpiperidin-4-yl) sebacate, 4-stearoyloxy-2,2,6,6-tetramethylpiperidine, di(,2,2,6,6-tetramethylpiperidin-4-y1) sebacate and bis (1-octyloxy-2,2,6,-tetramethyl-4-piperidyl) sebacate; and 
         (c) a diaryl amine,
 wherein the weight ratio of (a):(b):(c) is about 5:1:4. 
 
       
     
     
         18 . The lubricating composition according to claim  1 , wherein the additive composition comprises by weight % of the lubricating composition:
 (a) the metal-free sulfur-containing compound at about 0.5%,   (b) the hindered amine at about 0.1%, and   (c) the diaryl amine at about 0.4%.   
     
     
         19 . The lubricating composition according to claim  1 , wherein the ashless dithiocarbamate is methlyenebis(dibutyldithiocarbamate). 
     
     
         20 . The lubricating composition according to claim  1 , wherein the hindered amine is chosen from the group consisting of 4-stearoyloxy-2,2,6,6-tetramethylpiperidine; di(2,2,6,6-tetramethylpiperidin-4-yl) sebacate; di(1,2,2,6,6-pentamethylpiperidin-4-yl) sebacate; and 2,2,6,6-tetramethylpiperidinyl-4-dodecanate 
     
     
         21 . A lubricating composition comprising at least 90% by weight of a lubricant basestock, and about 0.5-5% by weight of an antioxidant additive composition comprising:
 (a) a sulfurized fatty acid,   (b) a hindered amine being one or more chosen from the group consisting of:   (1) a compound of the formula   
       
         
           
           
               
               
           
         
       
       where R 26  is H, O or a hydrocarbon from 1 to 25 carbon atoms, an alkoxy radical with the oxygen bound to the nitrogen with the alkyl portion containing 1 to 25 carbon atoms, or a COR group, the R being a hydrocarbon containing from 1 to 25 carbon atoms; R 27 , R 28 , R 32 , R 33  are hydrocarbons with 1 to 25 carbon atoms; R 29 , R 31  are H or hydrocarbons with 1 to 25 carbon atoms; when n=1, R 30  is OH, H, O, NH 2 , NR 2  where R is a hydrocarbon with 1 to 25 carbon atoms, an ester group O 2 CR where R is a hydrocarbon with 1 to 25 carbon atoms, or a succinimide group; when n=2, R 30  is the diacyl radical of an aliphatic dicarboxylic acid having 4 to 12 carbon atoms;
 (2) 4-stearoyloxy-2,2,6,6-tetramethylpiperidine, 
 (3) di(2,2,6,6-tetramethylpiperidin-4-yl) sebacate, 
 (4) di(1,2,2,6,6-pentamethylpiperidin-4-yl) sebacate, 
 (5) bis (1-octyloxy-2,2,6,-tetramethyl-4-piperidyl) sebacate 
 (6) polymer-bound piperidine compound, 
 (7) a compound of the group consisting of 2,2,6,6-tetramethylpiperidines, 1,2,2,6,6-pentamethylpiperidines, 1-oxo-2,2,6,6-tetramethylpiperidines, and 1-alkoxy-2,2,6,6-tetramethylpiperidines, and 
 (8) a compound of the group consisting of di(1,2,2,6,6-pentamethylpiperidin-4-yl) sebacate, 4-stearoyloxy-2,2,6,6-tetramethylpiperidine, di(,2,2,6,6-tetramethylpiperidin-4-yl) sebacate and bis (1-octyloxy-2,2,6,-tetramethyl-4-piperidyl) sebacate, and 
 (c) a diaryl amine