Refrigerant composition

Abstract

This invention describes a new refrigerant/lubricant combination for use in stationary and mobile refrigeration and air conditioning applications. In these applications, the refrigerant and lubricant must be soluble in each other (e.g., miscible) to ensure adequate lubricant circulation from the compressor, through the condenser, expansion device, and evaporator, and back to the compressor. Insufficient lubricant circulation will result in compressor failure. Low temperature solubility is particularly important to ensure lubricant flow through the cold evaporator. In addition, the lubricant and refrigerant combination should be stable in the presence of steel, and aluminum and copper containing metals. This invention describes the combination of refrigerant difluoroethane (e.g. R-152a) and polar, oxygenated lubricants, particular polyalkylene glycols (PAGs) and polyolesters (POEs) which may be used as a replacement for R-134a.

1 . A refrigerant composition comprising:
 a refrigerant consisting essentially of 1,1-difluoroethane;   a lubricant consisting essentially of a random copolymer of polyoxyalkylene glycol (PAG); and   an additives packages comprising an extreme pressure additive,   wherein the viscosity of the composition is between about 40 and 150 cSt at 40° C. and the lubricant is miscible in the refrigerant between about −40° C. and about 40° C.   
     
     
         2 . The refrigerant composition of  claim 1  wherein the PAG is a monol and based on about 5% to about 95% ethylene oxide and about 95% to about 5% propylene oxide. 
     
     
         3 . The refrigerant composition of  claim 2  wherein the PAG is based on about 25% to about 75% ethylene oxide and about 75% to about 25% propylene oxide. 
     
     
         4 . The refrigerant composition of  claim 1  wherein the PAG is alkyl ether capped and based on about 5% to about 95% ethylene oxide and about 95% to about 5% propylene oxide. 
     
     
         5 . The refrigerant composition of  claim 4  wherein the PAG is based on about 25% to about 75% ethylene oxide and about 75% to about 25% propylene oxide. 
     
     
         6 . The refrigerant composition of  claim 5  wherein the PAG is methyl double end capped. 
     
     
         7 . The refrigerant composition of  claim 1  wherein the additives package further comprises a gaseous phase flame retardant. 
     
     
         8 . The refrigerant composition of  claim 1  wherein the additives package further comprises a flame retardant selected from trifluorochloromethane, trifluoroiodomethane, phosphorus compounds, phosphate esters, hydrocarbons that contain iodine or bromine, hydrofluorocarbons that contain iodine or bromine, and fluorocarbons that contain iodine or bromine. 
     
     
         9 - 14 . (canceled) 
     
     
         15 . The refrigerant composition of  claim 3  wherein the additives package further comprises a flame retardant selected from trifluorochloromethane, trifluoroiodomethane, phosphorus compounds, phosphate esters, hydrocarbons that contain iodine or bromine, hydrofluorocarbons that contain iodine or bromine, and fluorocarbons that contain iodine or bromine. 
     
     
         16 . The refrigerant composition of  claim 5  wherein the additives package further comprises a flame retardant selected from trifluorochloromethane, trifluoroiodomethane, phosphorus compounds, phosphate esters, hydrocarbons that contain iodine or bromine, hydrofluorocarbons that contain iodine or bromine, and fluorocarbons that contain iodine or bromine. 
     
     
         17 . The refrigerant composition of  claim 2  wherein the PAG includes a PAG which is initiated with methanol, butanol, or a combination. 
     
     
         18 . The refrigerant composition of  claim 3  wherein the PAG includes a PAG which is initiated with methanol, butanol, or a combination. 
     
     
         19 . The refrigerant composition of  claim 3  wherein the lubricant is present at a concentration between about 1 wt. % and 50 wt %. 
     
     
         20 . The refrigerant composition of  claim 3  wherein the lubricant is present at a concentration between about 3 wt. % and 30 wt %. 
     
     
         21 . The refrigerant composition of  claim 6  wherein the lubricant is present at a concentration between about 1 wt. % and 50 wt %. 
     
     
         22 . The refrigerant composition of  claim 8  wherein the lubricant is present at a concentration between about 3 wt. % and 30 wt %. 
     
     
         23 . A refrigerant composition comprising:
 (i) a refrigerant consisting essentially of 1,1-difluoroethane;   (ii) from about 3 wt. % to about 30 wt. % of a lubricant consisting essentially of a random copolymer of a polyoxyalkylene glycol (PAG) which is initiated by a monol and contains from about 25% to about 75% ethylene oxide and from about 25% to about 75% propylene oxide; and   an additives packages comprising an extreme pressure additive,   wherein the viscosity of the composition is between about 40 and 150 cSt at 40° C., the additives package further includes a phosphate ester, and the lubricant is miscible in the refrigerant between about −40° C. and about 40° C.   
     
     
         24 . A refrigerant composition of  claim 23 , wherein the PAG comprises a PAG selected from the group consisting of a methyl ether capped PAG, an ethyl ether capped PAG, a propyl ether capped PAG, a butyl ether capped PAG, and any combination thereof. 
     
     
         25 . A refrigerant composition of  claim 23 , wherein the PAG is initiated with methanol. 
     
     
         26 . A refrigerant composition of  claim 23 , wherein the PAG is initiated with butanol.