Lubricant compositions having improved low temperature properties

Abstract

The pour points of lubricating compositions are significantly improved when Group III and GTL base stocks are formulated with alkyl alkaline earth metal detergents. In a preferred embodiment, calcium alkyl salicylate detergents are used.

1 . A method for improving the pour point of a lubricating composition comprising a major amount of a lubricating base oil and one or more detergents, the method comprising using a alkylated alkaline earth metal detergents as a pour point depressant. 
   
   
       2 . The method of  claim 1  wherein at least one alkaline earth metal detergents has a TBN of at least 65 and less than 280 
   
   
       3 . The method of  claim 2  wherein the alkyl salicylate detergent is a calcium salicylate. 
   
   
       4 . The method of  claim 2  wherein the alkaline earth metal is a calcium sulfonate. 
   
   
       5 . The method of  claim 2  wherein the alkaline earth metal is a calcium phenate. 
   
   
       6 . The method of  claim 1  wherein the base oil is chosen from the group consisting of Group III, GTL, and any combination thereof. 
   
   
       7 . A lubricating composition comprising:
 (a) a major amount of an oil of lubricating viscosity chosen from the group consisting of Group III, GTL and any combination thereof,   (b) an alkylated alkaline earth metal as a pour point depressant wherein the alkylated alkaline earth metal is greater than 0.4 and less than 10 weight percent, and   (c) a minor amount of at least one lubricant additives,   the composition having a saturates content greater than 98%, a viscosity index (VI) greater than 120 and a sulfur content less than 0.03 wt %.   
   
   
       8 . The composition of  claim 7  wherein the alkylated alkaline earth metal is chosen from the group consisting of calcium salicylate, calcium sulfonate, calcium phenate, and any combination thereof. 
   
   
       9 . The composition of  claim 8  wherein the alkylated earth metal is a calcium salicylate. 
   
   
       10 . The composition of  claim 7  wherein the composition is substantially free of any detergents and pour point depressants except for the alkylated alkaline earth metal. 
   
   
       11 . The composition of  claim 9  wherein the calcium salicylate detergent comprises a mixture of calcium salicylates, one having a TBN greater than 200, a second having a TBN of about 100 to 200 and a third having a TBN of less than 100. 
   
   
       12 . The composition of  claim 7  further comprising a Group IV base stock wherein the Group IV base stock is at least 4 and less than 10 weight percent of the composition. 
   
   
       13 . The composition of  claim 7  further comprising a PAO. 
   
   
       14 . A lubricating composition comprising:
 (a) greater than 50 weight percent of a base oil of lubricating viscosity selected from the group consisting of Group III, GTL, and any combination thereof; and   (b) an alkylated alkaline earth metal as a pour point depressant wherein the alkylated alkaline earth metal is greater than 0.4 and less than 10 weight percent;   (c) at least one lubricant performance enhancing additives,   the composition having a saturates content greater than 98%, a viscosity index (VI) greater than 120 and a sulfur content less than 0.03 wt %.   
   
   
       15 . In the lubrication of an engine with a crankcase lubricant wherein the lubricant additionally is used to perform a hydraulic function, the improvement comprising using as the crankcase lubricant the composition of any one of  claims 7  to  14 . 
   
   
       16 . The composition of  claim 14  wherein the alkylated alkaline earth metal is chosen from the group consisting of calcium salicylate, calcium sulfonate, calcium phenate, and any combination thereof. 
   
   
       17 . The composition of  claim 14  wherein the alkylated earth metal is a calcium salicylate. 
   
   
       18 . The composition of  claim 14  wherein the composition is substantially free of any detergents and pour point depressants except for the alkylated alkaline earth metal. 
   
   
       19 . The composition of  claim 14  wherein the calcium salicylate detergent comprises a mixture of calcium salicylates, one having a TBN greater than 200, a second having a TBN of about 100 to 200 and a third having a TBN of less than 100. 
   
   
       20 . The composition of  claim 14  further comprising a Group IV base stock wherein the Group IV base stock is at least 4 and less than 10 weight percent of the composition. 
   
   
       21 . The composition of  claim 14  further comprising a PAO. 
   
   
       22 . The use of at least one alkylated earth metal as a pour point depressant. 
   
   
       23 . The use according to  claim 22 , wherein the alkylated earth metal is used in a lubricant wherein at least one base stock of the lubricant is chosen form the group consisting of Group III, GTL, and any combination thereof. 
   
   
       24 . The use according to  claim 23  wherein the alkylated earth metal is a calcium salicylate. 
   
   
       25 . The composition of  claim 8  wherein an alkyl group on an aromatic ring of the alkaline earth metal detergent is linear and comprises of C8 to C30 more preferably from C12 to C18 carbon atoms.