Lubricant composition for automotive transmission

Abstract

A lubricating composition contains at least one base oil and at least one phosphite polymer having the formula (I) wherein each of R1, R2, R3 and R4 can be independently selected from the C1-C20 alkyl, C3-C22 alkenyl, C6-C40 cycloalkyl, C7-C40 cycloalkenyl, C1-20 methoxy alkyl glycol ethers and Y—OH groups; Y is selected from among the C2-C40 alkylene, C2-C40 alkyl lactone groups; —R7—(N(R8)—R9—, wherein R7, R8 and R9 are independently selected from among hydrogen, C1-C20 alkyl, C3-C22 alkenyl, C6-C40 cycloalkyl, C7-C40 cycloalkenyl, C1-20 methoxy alkyl glycol ethers; m is an integer from 2 to 100; and n is an integer from 1 to 1000.

1 . A lubricant composition comprising:
 at least one base oil; and   at least one phosphite polymer of formula (I):   
       
         
           
           
               
               
           
         
         where: 
         each of R 1 , R 2 , R 3  and R 4  can each be independently selected from among the following groups: C 1 -C 20  alkyl, C 3 -C 22  alkenyl, C 6 -C 40  cycloalkyl, C 7 -C 40  cycloalkenyl, C 1-20  methoxy alkyl glycol ethers and Y—OH; 
         Y is selected from among the following groups: C 2 -C 40  alkylene, C 2 -C 40  alkyl lactone, —R 7 —N(R 8 )—R 9 — where R 7 , R 8  and R 9  are each independently selected from among hydrogen, C 1 -C 20  alkyl, C 3 -C 22  alkenyl, C 6 -C 40  cycloalkyl, C 7 -C 40  cycloalkenyl, C 1-20  methoxy alkyl glycol ethers. 
         m is an integer ranging from 2 to 100; and 
         n is an integer ranging from 1 to 1000. 
       
     
     
         2 . The lubricant composition according to  claim 1 , wherein the polymer of formula (I) has a weight average molecular weight lower than 30000 g/mol. 
     
     
         3 . The lubricant composition according to  claim 1 , wherein the phosphite polymer represents from 0.01 to 10% by weight of the total weight of the lubricant composition. 
     
     
         4 . The lubricant composition according to  claim 1 , comprising from 5 to 9150 ppm by weight of phosphorus, relative to the total weight of the lubricant composition. 
     
     
         5 . The lubricant composition according to  claim 1 , further comprising at least one antiwear additive selected from among phosphorus antiwear additives, sulfur antiwear additives, sulfur-phosphorus antiwear additives, phosphorus-amine antiwear additives, sulfur-amine antiwear additives, and mixtures thereof. 
     
     
         6 . The lubricant composition according to  claim 1 , comprising from 0.01 to 5% by weight of antiwear additive(s) selected from among phosphorus antiwear additives, sulfur antiwear additives, sulfur-phosphorus antiwear additives, phosphorus-amine antiwear additives, sulfur-amine antiwear additives, and mixtures thereof. 
     
     
         7 . The lubricant composition according to  claim 1 , comprising from de 5 to 4000 ppm by weight of sulfur, relative to the total weight of the lubricant composition. 
     
     
         8 . The lubricant composition according to  claim 1 , comprising:
 70 to 99% by weight of one or more base oils; and   0.01 to 10% by weight of phosphite polymer;   optionally, from 0.01 to 5% by weight of antiwear additive(s) selected from among phosphorus antiwear additives, sulfur antiwear additives, sulfur-phosphorus antiwear additives, phosphorus-amine antiwear additives, sulfur-amine antiwear additives, and mixtures thereof; and   optionally from 1 to 30% by weight of one or more functional additives,   relative to the total weight of the lubricant composition.   
     
     
         9 . A method for improving the load-carrying capacity of a lubricant composition comprising at least one base oil, the method comprising adding a phosphite polymer into the lubricant composition, said phosphite polymer replying to formula (I): 
       
         
           
           
               
               
           
         
         where: 
         each of R 2 , R 3  and R 4  can each be independently selected from among the following groups: C 1 -C 20  alkyl, C 3 -C 22  alkenyl, C 6 -C 40  cycloalkyl, C 7 -C 40  cycloalkenyl, C 1-20  methoxy alkyl glycol ethers and Y—OH; 
         Y is selected from among the following groups: C 2 -C 40  alkylene, C 2 -C 40  alkyl lactone, —R 7 —N(R 8 )—R 9 — where R 7 , R 8  and R 9  are each independently selected from among hydrogen, C 1 -C 20  alkyl, C 3 -C 22  alkenyl, C 6 -C 40  cycloalkyl, C 7 -C 40  cycloalkenyl, C 1-20  methoxy alkyl glycol ethers; 
         m is an integer ranging from 2 to 100; and 
         n is an integer ranging from 1 to 1000. 
       
     
     
         10 . A method for lubricating at least one mechanical part of an automotive vehicle, the method comprising contacting the composition according to  claim 1  with the at least one mechanical part of an automotive vehicle. 
     
     
         11 . The lubricant composition according to  claim 1 , wherein the polymer of formula (I) has a weight average molecular weight ranging from 5000 to 20000 g/mol. 
     
     
         12 . The lubricant composition according to  claim 1 , comprising from 5 to 4500 ppm by weight of phosphorus, relative to the total weight of the lubricant composition. 
     
     
         13 . The lubricant composition according to  claim 1 , comprising from de 7 to 1000 ppm by weight of sulfur, relative to the total weight of the lubricant composition. 
     
     
         14 . The lubricant composition according to  claim 1 , comprising from de 10 to 800 ppm by weight of sulfur, relative to the total weight of the lubricant composition. 
     
     
         15 . The lubricant composition according to  claim 8 , wherein the functional additives are selected from among viscosity index improver additives, antioxidant additives, defoaming additives, dispersants, detergents, viscosity modifying additives, and mixtures thereof. 
     
     
         16 . The method according to  claim 10 , wherein the mechanical part of an automotive vehicle is contained in a transmission component of an automotive vehicle. 
     
     
         17 . The method according to  claim 16 , wherein the mechanical part of an automotive vehicle is contained in a transmission component of an automotive vehicle is a gear of an automotive vehicle.