Refrigerant additive compositions containing perfluoropolyethers
View Patent ↗The present invention relates to compositions and processes of using perfluoropolyether to maintain or improve the oil return, lubrication, cooling capacity, or energy efficiency of a refrigeration, air conditioning or heat transfer system.
1. A method of producing refrigeration, said method comprising evaporating a composition in the vicinity of a body to be cooled and thereafter condensing said composition; wherein said composition consists of:
a. a refrigerant or heat transfer fluid consisting of 2,3,3,3-tetrafluoro-1-propene (CH 2 ═CFCF 3 ) or 1,3,3,3-tetrafluoro-1-propene (CHF═CHCF 3 ); and
b. at least one perfluoropolyether; and optionally
c. a lubricant oil which is mineral oil or synthetic oil selected from the group consisting of alkylbenzene, polyol ester, polyalkylene glycols, polyvinyl ethers, carbonates, polyalphaolefin and combinations thereof;
wherein said perfluoropolyether has two end groups; wherein each of the two end groups of the perfluoropolyether, independently, is either an unfunctionalized, branched or straight chain perfluoroalkyl radical, or a functionalized group selected from the group consisting of esters, hydroxyls, amines, amides, cyanos, carboxylic acids and sulfonic acids;
and wherein said evaporating and said condensing is in a mobile air-conditioning system.
2. The method of claim 1 , wherein the amount of perfluoropolyether in said composition is less than about 40% by weight relative to said refrigerant or heat transfer fluid.
3. The method of claim 1 , wherein at least one of the end groups of said perfluoropolyether is carboxylic acid.
4. The method of claim 1 , wherein at least one of the end groups of said perfluoropolyether is sulfonic acid.
5. The method of claim 1 , wherein the mobile air-conditioning system is an automobile air-conditioning apparatus.