Refrigeration lubricant composition

Abstract

A refrigeration lubricant composition comprises an ester obtained from a mixed alcohol and a mixed carboxylic acid as a main component. The mixed alcohol comprises 65 to 99.95 mol % of pentaerythritol and 0.05 to 35 mol % of dipentaerythritol, the mixed carboxylic acid comprises 25 to 55 mol % of monocarboxylic acid having 5 to 8 carbon atoms and 45 to 75 mol % of isononanoic acid, and the composition has a hydroxyl value of 5.0 mgKOH/g or less and an acid value of 0.05 mgKOH/g or less.

1 . A refrigeration lubricant composition comprising a mixed ester obtained from a mixed alcohol and a mixed carboxylic acid as a main component, 
 wherein the mixed alcohol comprises 65 to 99.95 mol % of pentaerythritol and 0.05 to 35 mol % of dipentaerythritol,    the mixed carboxylic acid comprises 25 to 55 mol % of monocarboxylic acid having 5 to 8 carbon atoms and 45 to 75 mol % of isononanoic acid, and    the composition has a hydroxyl value of 5.0 mgKOH/g or less and an acid value of 0.05 mgKOH/g or less.    
     
     
         2 . The composition of  claim 1 , wherein the mixed ester is obtained by a reaction of the mixed alcohol and the mixed carboxylic acid, wherein the mixed carboxylic acid and the mixed alcohol comprise carboxylic acids and alcohols, respectively, which satisfy the following relation:  
       
         
           
             
               
                 
                   
                     1.09 
                     ≦ 
                     
                       
                         { 
                         
                           
                             ∑ 
                             
                                 
                             
                             ⁢ 
                             
                               ( 
                               
                                 A 
                                 × 
                                 B 
                               
                               ) 
                             
                           
                           - 
                           
                             ( 
                             
                               C 
                               × 
                               D 
                             
                             ) 
                           
                         
                         } 
                       
                       E 
                     
                     ≦ 
                     1.33 
                   
                 
                 
                   
                     ( 
                     1 
                     ) 
                   
                 
               
             
           
         
         A: number of carbon atoms in main chain of a carboxylic acid in the mixed carboxylic acid  
         B: molar fraction of the carboxylic acid of item “A” 
         C: number of carbon atoms in the longest side chain of carboxylic acids in the mixed carboxylic acid  
         D: molar fraction of carboxylic acid having the longest side chain  
         E: average number of hydroxyl groups of each alcohol in the mixed alcohol  
       
     
     
         3 . The composition of  claim 1 , wherein a kinematic viscosity of the composition at 40° C. is 30 to 150 mm 2 /s.  
     
     
         4 . The composition of any of  claim 1 , wherein the isononanoic acid contains 88.50 to 99.95 mol % of 3,5,5-trimethylhexanoic acid.  
     
     
         5 . The composition of any of  claim 1 , wherein the composition is used for a chlorine-free hydrofluorocarbon refrigerant.  
     
     
         6 . A refrigerant working fluid comprising the refrigeration lubricant composition of  claim 1  and a chlorine-free hydrofluorocarbon refrigerant.  
     
     
         7 . A refrigerant compression type refrigerating apparatus comprising a compressor, a condenser, an expansion mechanism, an evaporator, and the working fluid of  claim 6 .  
     
     
         8 . The composition of  claim 2 , wherein a kinematic viscosity of the composition at 40° C. is 30 to 150 mm 2 /s.  
     
     
         9 . The composition of  claim 2 , wherein the isononanoic acid contains 88.50 to 99.95 mol % of 3,5,5-trimethylhexanoic acid.  
     
     
         10 . The composition of  claim 3 , wherein the isononanoic acid contains 88.50 to 99.95 mol % of 3,5,5-trimethylhexanoic acid.  
     
     
         11 . The composition of  claim 2 , wherein the composition is used for a chlorine-free hydrofluorocarbon refrigerant.  
     
     
         12 . The composition of  claim 3 , wherein the composition is used for a chlorine-free hydrofluorocarbon refrigerant.  
     
     
         13 . The composition of  claim 4 , wherein the composition is used for a chlorine-free hydrofluorocarbon refrigerant.  
     
     
         14 . A refrigerant working fluid comprising the refrigeration lubricant composition of  claim 2  and a chlorine-free hydrofluorocarbon refrigerant.  
     
     
         15 . A refrigerant working fluid comprising the refrigeration lubricant composition of  claim 3  and a chlorine-free hydrofluorocarbon refrigerant.  
     
     
         16 . A refrigerant working fluid comprising the refrigeration lubricant composition of  claim 4  and a chlorine-free hydrofluorocarbon refrigerant.  
     
     
         17 . A refrigerant working fluid comprising the refrigeration lubricant composition of  claim 5  and a chlorine-free hydrofluorocarbon refrigerant.