Refrigerant lubrificant composition comprising a foam-inducing additive

Abstract

A lubricant composition has a synthetic lubricant base oil, preferably a polyol ester, and a polyether foam-inducing additive. The composition is suitable for use in a refrigerant system, particularly with HFC refrigerant gases. The foam-inducing additive is an alternative to known silicon-containing foam-inducing additives, which are not suitable for all refrigerant systems.

1  A lubricant composition comprising; 
 a) a synthetic lubricant base oil; and  
 b) a foam-inducing additive, which comprises a polyether having the formula  
 X-O—(RO) n —Y  
 wherein—O—(RO) n — is a polyether backbone 
 R is a partially or fully halogenated alkyl group having 1 to 10 carbon atoms and wherein adjacent R groups may be the same or different  
 n is in the range 1 to 1000 and  
 x and y are end groups.  
 
 
     
     
         2  A lubricant composition according to  claim 1  wherein R is a fully halogenated alkyl group having 1 to 7 carbon atoms.  
     
     
         3 . A lubricant composition according to  claim 1  or  claim 2  wherein the halogen is fluorine.  
     
     
         4  A lubricant composition according to any one of  claims 1  to  3  wherein n is in the range 1 to 100.  
     
     
         5  A lubricant composition according to any one of  claims 1  to  4  wherein at least one of the end groups X and Y comprise at least one functionalised group.  
     
     
         6 . A lubricant composition according to  claim 5  wherein the at least one functionalised group is positioned at the extremity of the end group away from the polyether backbone.  
     
     
         7 . A lubricant composition according to  claim 5  or  claim 6  wherein the at least one functionalised group includes haloalkyl groups.  
     
     
         8 . A lubricant composition according to any one of  claims 1  to  7  wherein the foam-inducing additive is present at a level of between 0.0001 to 0.1% by weight of the lubricant composition.  
     
     
         9 . A lubricant composition according to any one of  claims 1  to  8  wherein the synthetic lubricant base oil is chosen from alkylbenzenes, polyvinyl ethers, polyalkylene glycols and esters.  
     
     
         10 . A lubricant composition according to  claim 9  wherein the synthetic lubricant base oil is an ester which is a derivative of a polyol.  
     
     
         11 . Use of a lubricant composition in a refrigeration system wherein the lubricant composition comprises 
 a) a synthetic lubricant base oil; and    b) a foam-inducing additive, which comprises a polyether having the formula    X-O—(RO) n —Y    wherein—O—(RO) n — is a polyether backbone 
 R is a partially or fully halogenated alkyl group having 1 to 10 carbon atoms and wherein adjacent R groups may be the same or different  
 n is in the range 1 to 1000 and  
 X and Y are end groups.