Lubricating fluid

Abstract

A lubricating fluid suitable for use as a shock absorber fluid is disclosed. The lubricating fluid comprises at least 40 wt %, based upon the weight of the lubricating fluid, of a GTL base oil, has a viscosity index in the range of from 50 to 1000, and a pour point of below −30° C.

1 . A lubricating fluid comprising:
 (a) at least 40 wt %, based upon the weight of the lubricating fluid, of a GTL base oil;   (b) from 5 to 25 wt %, based upon the weight of the lubricating fluid, of alkylbenzene or alkylnaphthalene; and   (c) from 0.1 to 20 wt %, based upon the weight of the lubricating fluid, of a viscosity index improver;   
       wherein the lubricating fluid has a viscosity index in the range of from 50 to 1000, and a pour point of below −30° C. 
     
     
         2 . The lubricating fluid according to  claim 1 , comprising in the range of from 50 to 90 wt % of the GTL base oil. 
     
     
         3 . The lubricating fluid according to  claim 1 , comprising from 5 to 25 wt % of a mixture of alkylbenzenes that are mono- or di-substituted with linear and/or branched alkyl groups, wherein the alkyl groups are C 6 -C 20  alkyl groups. 
     
     
         4 . The lubricating fluid according to  claim 1 , wherein the viscosity index improver is chosen from polymers and copolymers of methacrylate, butadiene, olefins, or alkylated styrenes. 
     
     
         5 . The lubricating fluid according to  claim 1 , comprising a metal-containing or metal-free alkylthiophosphate, in an amount of from about 0.4% by weight to about 1.4% by weight of the lubricating fluid. 
     
     
         6 . The lubricating fluid according to  claim 1  comprising an acrylic copolymer or a fatty amine ethoxylate in an amount less than 0.1 wt %, based up on the weight of the lubricating fluid. 
     
     
         7 . (canceled) 
     
     
         8 . A method of operating a shock absorber in a vehicle, the method comprising:
 providing the shock absorber with a lubricating fluid, wherein the lubricating fluid comprises:   (a) at least 40 wt %, based upon the weight of the lubricating fluid, of a GTL base oil;   (b) from 5 to 25 wt %, based upon the weight of the lubricating fluid, of alkylbenzene or alkylnaphthalene; and   (c) from 0.1 to 20 wt %, based upon the weight of the lubricating fluid, of a viscosity index improver;   
       wherein the lubricating fluid has a viscosity index in the range of from 50 to 1000, and a pour point of below −30° C.