Classifications

• • C—CHEMISTRY; METALLURGY
  • C10—PETROLEUM, GAS OR COKE INDUSTRIES; TECHNICAL GASES CONTAINING CARBON MONOXIDE; FUELS; LUBRICANTS; PEAT
  • C10M—LUBRICATING COMPOSITIONS; USE OF CHEMICAL SUBSTANCES EITHER ALONE OR AS LUBRICATING INGREDIENTS IN A LUBRICATING COMPOSITION
  • C10M171/00—Lubricating compositions characterised by purely physical criteria, e.g. containing as base-material, thickener or additive, ingredients which are characterised exclusively by their numerically specified physical properties, i.e. containing ingredients which are physically well-defined but for which the chemical nature is either unspecified or only very vaguely indicated
  • C10M171/008—Lubricant compositions compatible with refrigerants
• • C—CHEMISTRY; METALLURGY
  • C09—DYES; PAINTS; POLISHES; NATURAL RESINS; ADHESIVES; COMPOSITIONS NOT OTHERWISE PROVIDED FOR; APPLICATIONS OF MATERIALS NOT OTHERWISE PROVIDED FOR
  • C09K—MATERIALS FOR MISCELLANEOUS APPLICATIONS, NOT PROVIDED FOR ELSEWHERE
  • C09K5/00—Heat-transfer, heat-exchange or heat-storage materials, e.g. refrigerants; Materials for the production of heat or cold by chemical reactions other than by combustion
  • C09K5/02—Materials undergoing a change of physical state when used
  • C09K5/04—Materials undergoing a change of physical state when used the change of state being from liquid to vapour or vice versa
  • C09K5/041—Materials undergoing a change of physical state when used the change of state being from liquid to vapour or vice versa for compression-type refrigeration systems
  • C09K5/044—Materials undergoing a change of physical state when used the change of state being from liquid to vapour or vice versa for compression-type refrigeration systems comprising halogenated compounds
  • C09K5/045—Materials undergoing a change of physical state when used the change of state being from liquid to vapour or vice versa for compression-type refrigeration systems comprising halogenated compounds containing only fluorine as halogen
• • C—CHEMISTRY; METALLURGY
  • C10—PETROLEUM, GAS OR COKE INDUSTRIES; TECHNICAL GASES CONTAINING CARBON MONOXIDE; FUELS; LUBRICANTS; PEAT
  • C10M—LUBRICATING COMPOSITIONS; USE OF CHEMICAL SUBSTANCES EITHER ALONE OR AS LUBRICATING INGREDIENTS IN A LUBRICATING COMPOSITION
  • C10M105/00—Lubricating compositions characterised by the base-material being a non-macromolecular organic compound
  • C10M105/08—Lubricating compositions characterised by the base-material being a non-macromolecular organic compound containing oxygen
  • C10M105/32—Esters
  • C10M105/38—Esters of polyhydroxy compounds
• • C—CHEMISTRY; METALLURGY
  • C09—DYES; PAINTS; POLISHES; NATURAL RESINS; ADHESIVES; COMPOSITIONS NOT OTHERWISE PROVIDED FOR; APPLICATIONS OF MATERIALS NOT OTHERWISE PROVIDED FOR
  • C09K—MATERIALS FOR MISCELLANEOUS APPLICATIONS, NOT PROVIDED FOR ELSEWHERE
  • C09K2205/00—Aspects relating to compounds used in compression type refrigeration systems
  • C09K2205/22—All components of a mixture being fluoro compounds
• • C—CHEMISTRY; METALLURGY
  • C10—PETROLEUM, GAS OR COKE INDUSTRIES; TECHNICAL GASES CONTAINING CARBON MONOXIDE; FUELS; LUBRICANTS; PEAT
  • C10M—LUBRICATING COMPOSITIONS; USE OF CHEMICAL SUBSTANCES EITHER ALONE OR AS LUBRICATING INGREDIENTS IN A LUBRICATING COMPOSITION
  • C10M2207/00—Organic non-macromolecular hydrocarbon compounds containing hydrogen, carbon and oxygen as ingredients in lubricant compositions
  • C10M2207/28—Esters
  • C10M2207/281—Esters of (cyclo)aliphatic monocarboxylic acids
• • C—CHEMISTRY; METALLURGY
  • C10—PETROLEUM, GAS OR COKE INDUSTRIES; TECHNICAL GASES CONTAINING CARBON MONOXIDE; FUELS; LUBRICANTS; PEAT
  • C10M—LUBRICATING COMPOSITIONS; USE OF CHEMICAL SUBSTANCES EITHER ALONE OR AS LUBRICATING INGREDIENTS IN A LUBRICATING COMPOSITION
  • C10M2207/00—Organic non-macromolecular hydrocarbon compounds containing hydrogen, carbon and oxygen as ingredients in lubricant compositions
  • C10M2207/28—Esters
  • C10M2207/282—Esters of (cyclo)aliphatic oolycarboxylic acids
• • C—CHEMISTRY; METALLURGY
  • C10—PETROLEUM, GAS OR COKE INDUSTRIES; TECHNICAL GASES CONTAINING CARBON MONOXIDE; FUELS; LUBRICANTS; PEAT
  • C10M—LUBRICATING COMPOSITIONS; USE OF CHEMICAL SUBSTANCES EITHER ALONE OR AS LUBRICATING INGREDIENTS IN A LUBRICATING COMPOSITION
  • C10M2207/00—Organic non-macromolecular hydrocarbon compounds containing hydrogen, carbon and oxygen as ingredients in lubricant compositions
  • C10M2207/28—Esters
  • C10M2207/283—Esters of polyhydroxy compounds
• • C—CHEMISTRY; METALLURGY
  • C10—PETROLEUM, GAS OR COKE INDUSTRIES; TECHNICAL GASES CONTAINING CARBON MONOXIDE; FUELS; LUBRICANTS; PEAT
  • C10M—LUBRICATING COMPOSITIONS; USE OF CHEMICAL SUBSTANCES EITHER ALONE OR AS LUBRICATING INGREDIENTS IN A LUBRICATING COMPOSITION
  • C10M2207/00—Organic non-macromolecular hydrocarbon compounds containing hydrogen, carbon and oxygen as ingredients in lubricant compositions
  • C10M2207/28—Esters
  • C10M2207/286—Esters of polymerised unsaturated acids
• • C—CHEMISTRY; METALLURGY
  • C10—PETROLEUM, GAS OR COKE INDUSTRIES; TECHNICAL GASES CONTAINING CARBON MONOXIDE; FUELS; LUBRICANTS; PEAT
  • C10M—LUBRICATING COMPOSITIONS; USE OF CHEMICAL SUBSTANCES EITHER ALONE OR AS LUBRICATING INGREDIENTS IN A LUBRICATING COMPOSITION
  • C10M2211/00—Organic non-macromolecular compounds containing halogen as ingredients in lubricant compositions
  • C10M2211/02—Organic non-macromolecular compounds containing halogen as ingredients in lubricant compositions containing carbon, hydrogen and halogen only
  • C10M2211/022—Organic non-macromolecular compounds containing halogen as ingredients in lubricant compositions containing carbon, hydrogen and halogen only aliphatic
• • C—CHEMISTRY; METALLURGY
  • C10—PETROLEUM, GAS OR COKE INDUSTRIES; TECHNICAL GASES CONTAINING CARBON MONOXIDE; FUELS; LUBRICANTS; PEAT
  • C10M—LUBRICATING COMPOSITIONS; USE OF CHEMICAL SUBSTANCES EITHER ALONE OR AS LUBRICATING INGREDIENTS IN A LUBRICATING COMPOSITION
  • C10M2211/00—Organic non-macromolecular compounds containing halogen as ingredients in lubricant compositions
  • C10M2211/06—Perfluorinated compounds
• • C—CHEMISTRY; METALLURGY
  • C10—PETROLEUM, GAS OR COKE INDUSTRIES; TECHNICAL GASES CONTAINING CARBON MONOXIDE; FUELS; LUBRICANTS; PEAT
  • C10N—INDEXING SCHEME ASSOCIATED WITH SUBCLASS C10M RELATING TO LUBRICATING COMPOSITIONS
  • C10N2040/00—Specified use or application for which the lubricating composition is intended
• • C—CHEMISTRY; METALLURGY
  • C10—PETROLEUM, GAS OR COKE INDUSTRIES; TECHNICAL GASES CONTAINING CARBON MONOXIDE; FUELS; LUBRICANTS; PEAT
  • C10N—INDEXING SCHEME ASSOCIATED WITH SUBCLASS C10M RELATING TO LUBRICATING COMPOSITIONS
  • C10N2040/00—Specified use or application for which the lubricating composition is intended
  • C10N2040/30—Refrigerators lubricants or compressors lubricants
• • C—CHEMISTRY; METALLURGY
  • C10—PETROLEUM, GAS OR COKE INDUSTRIES; TECHNICAL GASES CONTAINING CARBON MONOXIDE; FUELS; LUBRICANTS; PEAT
  • C10N—INDEXING SCHEME ASSOCIATED WITH SUBCLASS C10M RELATING TO LUBRICATING COMPOSITIONS
  • C10N2040/00—Specified use or application for which the lubricating composition is intended
  • C10N2040/32—Wires, ropes or cables lubricants
• • C—CHEMISTRY; METALLURGY
  • C10—PETROLEUM, GAS OR COKE INDUSTRIES; TECHNICAL GASES CONTAINING CARBON MONOXIDE; FUELS; LUBRICANTS; PEAT
  • C10N—INDEXING SCHEME ASSOCIATED WITH SUBCLASS C10M RELATING TO LUBRICATING COMPOSITIONS
  • C10N2040/00—Specified use or application for which the lubricating composition is intended
  • C10N2040/34—Lubricating-sealants
• • C—CHEMISTRY; METALLURGY
  • C10—PETROLEUM, GAS OR COKE INDUSTRIES; TECHNICAL GASES CONTAINING CARBON MONOXIDE; FUELS; LUBRICANTS; PEAT
  • C10N—INDEXING SCHEME ASSOCIATED WITH SUBCLASS C10M RELATING TO LUBRICATING COMPOSITIONS
  • C10N2040/00—Specified use or application for which the lubricating composition is intended
  • C10N2040/36—Release agents or mold release agents
• • C—CHEMISTRY; METALLURGY
  • C10—PETROLEUM, GAS OR COKE INDUSTRIES; TECHNICAL GASES CONTAINING CARBON MONOXIDE; FUELS; LUBRICANTS; PEAT
  • C10N—INDEXING SCHEME ASSOCIATED WITH SUBCLASS C10M RELATING TO LUBRICATING COMPOSITIONS
  • C10N2040/00—Specified use or application for which the lubricating composition is intended
  • C10N2040/38—Conveyors or chain belts
• • C—CHEMISTRY; METALLURGY
  • C10—PETROLEUM, GAS OR COKE INDUSTRIES; TECHNICAL GASES CONTAINING CARBON MONOXIDE; FUELS; LUBRICANTS; PEAT
  • C10N—INDEXING SCHEME ASSOCIATED WITH SUBCLASS C10M RELATING TO LUBRICATING COMPOSITIONS
  • C10N2040/00—Specified use or application for which the lubricating composition is intended
  • C10N2040/40—Generators or electric motors in oil or gas winning field
• • C—CHEMISTRY; METALLURGY
  • C10—PETROLEUM, GAS OR COKE INDUSTRIES; TECHNICAL GASES CONTAINING CARBON MONOXIDE; FUELS; LUBRICANTS; PEAT
  • C10N—INDEXING SCHEME ASSOCIATED WITH SUBCLASS C10M RELATING TO LUBRICATING COMPOSITIONS
  • C10N2040/00—Specified use or application for which the lubricating composition is intended
  • C10N2040/42—Flashing oils or marking oils
• • C—CHEMISTRY; METALLURGY
  • C10—PETROLEUM, GAS OR COKE INDUSTRIES; TECHNICAL GASES CONTAINING CARBON MONOXIDE; FUELS; LUBRICANTS; PEAT
  • C10N—INDEXING SCHEME ASSOCIATED WITH SUBCLASS C10M RELATING TO LUBRICATING COMPOSITIONS
  • C10N2040/00—Specified use or application for which the lubricating composition is intended
  • C10N2040/44—Super vacuum or supercritical use
• • C—CHEMISTRY; METALLURGY
  • C10—PETROLEUM, GAS OR COKE INDUSTRIES; TECHNICAL GASES CONTAINING CARBON MONOXIDE; FUELS; LUBRICANTS; PEAT
  • C10N—INDEXING SCHEME ASSOCIATED WITH SUBCLASS C10M RELATING TO LUBRICATING COMPOSITIONS
  • C10N2040/00—Specified use or application for which the lubricating composition is intended
  • C10N2040/50—Medical uses

Definitions

• the invention relates to refrigeration working fluid compositions uniquely designed for efficient operation in recompression type cooling system. More particularly this invention relates to refrigeration working fluid compositions comprising fluorocarbon (HFC) refrigerant blends and certain polyol ester lubricants having suitable viscosities and which are miscible with the refrigerant at low temperatures (i.e., below 120°C) while immiscible at higher temperatures (i.e., about 120-180°C or greater), thereby exhibiting reversible miscibility.
• HFC fluorocarbon
• Cooling systems of the mechanical vapor recompression type including refrigerators, freezers, heat pumps, air conditioning systems, and the like, are well known.
• a refrigerant of suitable boiling point evaporates at low pressure, taking heat from the surrounding zone.
• the resulting vapor is then compressed and passed to a condenser where it condenses and gives off heat to a second zone.
• the condensate is then returned through an expansion valve to the evaporator, so completing the cycle.
• Re rigeration working fluids are required to have a lubricant which is compatible and miscible with the refrigerant so that moving parts of the system are properly lubricated.
• lubricants have been composed of hydrocarbon mineral oils which are miscible with the chlorine-containing refrigerant fluids and which provide effective lubrication.
• U.S. Patent 5,021,179, issued June 4, 1991 to Zehler et al. discloses esters of polyols in which the acyl groups have at least 22% of (a) branched acyl groups or (b) acyl groups which contain no more than six carbon atoms.
• This patent also indicates that the esters have a certain ratio of the number percent of acyl groups that have 8 or more carbon atoms and are unbranched to the number percent of acyl groups that are branched and contain not more than 6 carbon atoms, and that this ratio is not greater than 1.56.
• the patent requires that the number percent of acyl groups having at least 9 carbon atoms, branched or not branched, will be not greater than 81.
• PCT Application WO 90/12849 published November 1, 1990 by Jolley et al. discloses generally liquid compositions containing a major amount of at least one fluorine containing hydrocarbon containing one or two carbon atoms and a minor amount of at least one soluble organic lubricant comprising at least one carboxylic ester of a polyhydroxy compound containing at least two hydroxy groups and having the formula R[0C(O)R'] n where R is hydrocarbyl, each R' is independently hydrogen, straight chain lower hydrocarbyl, a branched chain hydrocarbyl group, or a straight chain hydrocarbyl group containing from 8 to about 22 carbon atoms, provided that at least one R' group is hydrogen, a lower straight chain hydrocarbyl or a branched chain hydrocarbyl group, or a carboxylic acid-containing or carboxylic acid ester-containing hydrocarbyl group, and n is at least 2.
• Suitable lubricants are: esters of neopentyl glycol and a straight or branched- chain monovalent fatty acid having 3-18 carbon atoms; esters of pentaerythritol, dipentaerythritol and tripentaerythritol with straight or branched chain C2 ⁇ C ] _8 monovalent fatty acids; esters of a trihydroxy polyvalent alcohol of the formula RC(CH20H)3 where R is C1-C3 alkyl with a straight or branched-chain monovalent fatty acid having 2-18 carbon atoms and not more than 25 mol% per total fatty acid of at least one polybasic acid having carbon number of 4-36.
• esters said to be compatible with R134a, the esters being defined as having specific structures and being esters of mono-, di- and tri-pentaerythritol and other polyols such as trimethylolethane, trimethylolpropane, tri ethylolbutane or dimers or trimers thereof with monocarboxylic acids having 2-15 carbon atoms and dicarboxylic acids having 2-10 carbon atoms.
• the esters are generally said to have molecular weights of about 200-3000.
• neopentyl polyol ester of a fatty acid having 2 to 6 carbon atoms discloses lubricants compatible with R134a which are characterized at being neopentyl polyol ester of a fatty acid having 2 to 6 carbon atoms. It is said in this publication that the use of acids having 7 or more carbon atoms will result in incompatibility if the amount of C2-C 5 acids is not 20 mol% or greater such that the average number of carbon atoms of the fatty acids per hydroxyl group of the neopentylpolyol is 6 or below.
• Suitable neopentyl polyols include mono-, di- and tri- pentaerythritol, trimethylolpropane, and trimethylolethane. The polyols must have at least 3 OH groups.
• the working fluid composition comprising a mixture of refrigerant and lubricant is passed from the compressor, where the temperatures are highest and where the lubricant is needed, to the condenser, where temperatures are reduced. Thereafter, the working fluid composition is then sent on to the evaporator, where temperatures are coldest and where the lubricant is not needed. Thereafter the working fluid composition, in vapor form, is returned to the compressor for repetition of the cycle.
• the refrigerant working fluid compositions of this invention will exhibit partial or complete homogeneity and irascibility of the ester lubricant and the HFC refrigerant blends when the working fluid composition is in the evaporator, but when the working fluid composition is in the compressor, where temperatures are high and lubricant is needed, the ester lubricant in a very concentrated form is available for lubrication of the compressor since the ester lubricant and the refrigerant blends exhibit complete immiscibility at high temperatures, i.e., about 120°C to 180°C or greater. Thus, separation of the ester lubricant from the refrigerant blends in the compressor is beneficial.
• the working fluid compositions of this invention may also be partially miscible or semi-homogeneous at lower temperatures, i.e., the blend of ester and refrigerant may exhibit partial miscibility, but this partial miscibility or semi-homogeneity does not prevent their use in refrigeration equipment, and such semi-homogeneous compositions also exhibit substantially complete immiscibility at higher temperatures, i.e., at about 120°C to 180°C or greater, thereby capable of achieving the objectives of this invention.
• miscibility/immiscibility can be significantly influenced by blending refrigerants. More importantly, however, is the fact that the present inventors have discovered that the temperature/immiscibility relationship of refrigerant blends such as R125, R143a and R134a, or R125 and R143a, is inverse to that of conventionally known single component refrigerants with polyol esters.
• the present inventors have found that when the specific refrigerant blends of the present invention are mixed with polyol ester lubricants, the lubricants become immiscible at high temperatures allowing for separation of refrigerant and lubricant in the compressor section of a cooling system which operates at high temperatures, thereby allowing a certain portion of the lubricant to remain behind in the compressor section rather than cycling through the entire cooling system where the lubricant is not needed.
• single refrigerants such as R134a and R143a are immiscible at lower temperatures allowing for separation of refrigerant and lubricant in the evaporator section of the cooling system which operates at low temperatures, thereby allowing a certain portion of the lubricant to remain behind in the evaporator section where the lubricant is not needed and thereby depriving the compressor section of the much needed lubricant (See Figs. 3 and 4).
• a single refrigerant such as R125 is also undesirable since it is miscible at all temperatures which the cooling system operates, thereby causing the lubricant to pass from evaporator to compressor to condenser, in series, without the benefit of concentration and separation of an immiscible polyol ester lubricant in the compressor section which is sought by using the refrigerant blends of the present invention (See Fig. 5).
• refrigerants such as R32 are undesirable since they are miscible at high temperatures and immiscible at low temperatures (See Fig. 6). Such refrigerants cause the lubricant to separate out of the working fluid composition while in the evaporator section, thereby depriving the compressor section of the much needed lubricant.
• European Patent Publication No. 0 536 940 published on April 14, 1993, and assigned to Imperial Chemical Industries PLC discloses a working fluid comprising a heat transfer fluid comprising a mixture of at least two compounds selected from the group consisting of hydrofluoroalkanes and fluoroalkanes; and a lubricant.
• the heat transfer fluid may comprise two, three or more components selected from the group consisting of: R32, R134, R134a, R125, R152a, R143a and R143.
• One suitable heat transfer fluid comprises a mixture of R32 and R125.
• working fluid compositions which include a blend of R32 and R125 are not immiscible at higher temperatures, except for the composition having a lubricant of technical grade pentaerythritol, cekanoic 9 and cekonic 8 which exhibited immiscibility in the temperature range of between 100-130°C. If, however, you refer to Example E on Fig. 1, this lubricant is considered miscible at all temperatures in the refrigerant blend according to the present invention and in Example I on Fig. 2, this lubricant is considered immiscible from 120-180°C. Therefore, it quite clear that not all refrigerant blends act the same and that each blend of refrigerants exhibits its own unique miscibility and immiscibility properties.
• European Patent Publication No. 0 536 940 does not disclose the specific weight percents of the unique refrigerant blends (especially that of R134a) recited in the present invention nor the specific lubricants admixed with such blends, it cannot be conclusively stated that they would exhibit the same miscibility and immiscibility properties of the refrigeration working fluid composition of the present invention.
• One cannot readily determine from the miscibility data of a single refrigerant and lubricant what affect the blending of another refrigerant together with that single refrigerant would have on the miscibility properties of the resulting working fluid without the benefit of the extensive research efforts of the present inventors.
• blends of HFC refrigerants and polyol esters of certain monocarboxylic acids useful as refrigeration working fluids exhibiting reverse miscibility which provide improved lubrication of refrigeration equipment containing such compositions.
• the preferred working fluid compositions according to the present invention are as follows:
• a refrigeration working fluid composition which is miscible or partially miscible at temperatures of less than 120°C and which is immiscible at temperatures of at least about 120-180°C or greater, the refrigeration working fluid comprising:
• a refrigerant comprising a blend of pentafluoroethane, 1, 1, 1-trifluoroethane, and 1,1,1,2- tetrafluoroethane, wherein the tetrafiuoroethane is present in an amount of between about 0.5 to 10 weight %, based on the total weight of the refrigerant, and ( ⁇ ) about 5 to 35 weight % of a polyol ester lubricant, based on the total weight of the working fluid composition.
• a refrigeration working fluid composition which is miscible or partially miscible at temperatures of less than 120°C and which is immiscible at temperatures of at least about 120-180°C, the refrigeration working fluid comprising:
• a mechanical vapor recompression type cooling system comprising an evaporator, a compressor, and a condensor has refrigeration working fluid compositions (a) and (b) cycling therethrough, wherein the refrigeration working fluid composition is miscible or partially miscible in the evaporator at temperatures of less than 120°C and immiscible in the compressor at temperatures of at least about 120-180°C, whereby the polyol ester lubricant is separated from the refrigerant in the compressor when lubricant the is most needed and the polyol ester lubricant is miscible or partially miscible in the refrigerant while the refrigeration working fluid composition is contained in the evaporator such that the polyol ester lubricant can be readily transported from the evaporator to the compressor.
• Fig. 1 is a chart which show the reversible miscibility exhibited by the refrigeration working fluid composition of the present invention comprising a refrigerant of 44% R125, 52% R143a and 4% R134a and the selected polyol ester lubricants verses refrigeration working fluid compositions which do not exhibit reversible miscibility;
• Fig. 2 is a chart which show the reversible miscibility exhibited by the refrigeration working fluid composition of the present invention comprising a refrigerant of 55% R143a and 45% R125 and the selected polyol ester lubricants verses refrigeration working fluid compositions which do not exhibit reversible miscibility;
• Fig. 3 is a chart which shows the relative immiscibility of various polyol ester lubricants in R143a at any temperature;
• Fig. 4 is a chart which shows the relative miscibility of various polyol ester lubricants in R134a at any temperature
• Fig. 5 is a chart which shows the relative miscibility of various polyol ester lubricants in R125 at any temperature and the relative immiscibility of other polyol ester lubricants in R125 at any temperature;
• Fig. 6 is a chart which shows the reversible miscibility of various polyol ester lubricants in R32, wherein these lubricants are immiscible at low temperatures and miscible at higher temperatures which is completely inopposite to the present invention.
• Fig. 7 is a chart which shows the relative miscibility of various polyol ester lubricants in a refrigerant blend of 60 weight % R32 and 40 weight % R125 at any temperature, except for working fluids which are formed using TPE/CK9/CK8 which exhibited immiscibility in the narrow temperature range of between about 100-130°C.
• the polyol esters are present in an amount effective to provide lubrication, which is generally over the range of about 5-35% by weight based on the total weight or the refrigeration working fluid composition. Preferred amounts are 10%, 25% and 35% ester.
• the refrigeration working fluid compositions of this invention are preferably either:
• a refrigeration working fluid composition which is essentially a homogeneous or semi-homogeneous one phase composition at low temperatures but which exhibits immiscibility at temperatures of about 120- 180°C comprising (i) a refrigerant composed of a blend of 44 wt.% R-125, 52 wt.% R-143a, and 4 wt.% R-134a, and an effective amount of (ii) a polyol ester lubricant being (1) a trimethylolpropane ester of (a) 3,5,5-trimethylhexanoic acid, (b) a mixture of 67 % by weight n-heptanoic acid with 24 % by weight 2- methylhexanoic acid, 7 % by weight 2-ethylpentanoic acid and 2 % by weight mixed isomers of C alkanoic acids or (c) a mixture of heptanoic acids composed of about 25 wt.% 3, 4-dimethylpentanoic
• a refrigeration working fluid which is essentially a homogeneous or semi-homogeneous one phase composition at low temperatures but which exhibits immiscibility at temperature of 120-180SC comprising (a) a refrigerant composed of a mixture of 55-50 wt.% R-143a, and 45-50 wt.% R-125, and an effective amount of (b) a polyol ester lubricant being (1) a trimethylolpropane ester of (a) 2-ethyl hexanoic acid, (b) 3,5,5-trimethylhexanoic acid or (c) a mixture of branched heptanoic acids composed of 25 wt.% 3,4- di ethylpentanoic, 51% 3,4 and 5-methylhexanoic, 8% n- heptanoic, 5% 3-ethylpentanoic and the balance a mixture of other branched heptanoic acids; (2) a technical grade pen
• R125 refers to pentafluoroethane
• R143a refers to 1, 1, 1-trifluoroethane
• R134a refers to 1, 1, 1,2-tetrafluoroethane.
• Miscibility and immiscibility is determined in the following manner.
• a measured quantity of ester lubricant is poured into a valved glass tube of 12 mm I.D.
• the tube is connected to a R-134a refrigerant charging unit, where air is evacuated and a set volume of refrigerant is condensed into the glass tube until a desired refrigerant gas pressure drop is obtained.
• the composition of the lubricant/refrigerant mixture is calculated from weight measurements taken of the tube, tube plus lubricant, and tube plus lubricant plus refrigerant.
• the tube containing the lubricant/refrigerant is visually observed for miscibility at room temperature, in a high temperature visibility bath where the temperature is thermostatically controlled up to +180°C, and in a low temperature visibility bath where the temperature is thermostatically controlled down to -80°C.
• the mixture is considered miscible to a given temperature if one clear layer is observed.
• the mixture is considered immiscible if two separate layers are observed. Partial miscibility is any state between miscibility and immiscibility.
• miscibility temperature refers to the lowest temperature at which miscibility is observed at the given composition. The highest of these temperatures is the miscibility value for working fluid compositions having that ester lubricant.
• Figures 1 and 2 show the reversible miscibility exhibited by the compositions of the invention in plots which are composites for data obtained over three compositional ranges for each ester, i.e., 10%, 25% and 35% by weight ester. All percentages are by weight. Temperatures are in degrees centigrade.
• Figs. 1 and 2 also demonstrate that increased miscibility can be achieved by mixing refrigerants in the same way that it is achieved by mixing lubricants.
• the incompatibility R143 with polyol esters is almost eliminated when it is mixed with R125, even when R125 is the minority (i.e., less than 50%) component.
• compositions of the present invention i.e., Examples B, C, and D, contain the esters identified below:
• composition D TPE/CK7 - trimethylolpropane ester of mixed heptanoic acids ("Cekanoic 7 acid”) which is a mixture of 23% 2-ethylpentanoic acid, 74% 2-methylhexanoic acid and the balance other C 7 acid isomers.
• Comparative compositions A and E contain refrigerant blends of 44% R125, 52% R143a and 4% R134a admixed with the following esters:
• A Neopentyl glycol ester of 3,5,5- trimethylhexanoic acid.
• E technical grade pentaerythritol ester of a mixture of (a) 85 wt.% 3, 5, 5-trimethylhexanoic and (b) 15 wt.% isooctanoic acids which is a mixture of 26 wt.% 3,5-dimethyl-, 19% 4,5-dimethyl, 17% 3,4- dimethylhexanoic acid, 11% 5-methylheptanoic, 5% 4- methylheptanoic and the balance mixed methylheptanoic and dimethylhexanoic acids.
• compositions of the invention are compositions F, G and I containing these esters:
• F is the trimethylolpropane ester of 2-ethyl hexanoic acid.
• composition E is same ester as in composition E except there is used 75 wt.% of 3, 5, 5-trimethylhexanoic acid and 25% of the same mixture of isooctanoic acids.
• Comparative composition H contains refrigerant blends of 55% R143a and 45% R125 admixed with the following ester:
• compositional ranges of 10%, 25% and 35% by weight ester were evaluated over compositional ranges of 10%, 25% and 35% by weight ester with similar results:
• Composition J The trimethylol propane ester of a mixture of heptanoic acids (25% 3 , 4-dimethylpentanoic, 51% 3,4 and 5-methylhexanoic acids, 8% n-heptanoic, 5% 3-ethylpentanoic and the balance a mixture of other branched heptanoic acids) was mixed with a blend of 44% R-125, 52% R-143a and 4% R-134a and was found to be miscible at -50°C to +58°C and immiscible at higher temperatures.
• Composition K The technical grade pentaerythritol ester of n-pentanoic acid was evaluated with the same refrigerant blend as was Ester J and was found to be miscible at -50°C to +63°C and immiscible at higher temperatures.
• Composition L The same ester used in Composition J was mixed with a blend of 50% by weight 143a and 50% by weight R-125 and was found miscible at -50°C to +55°C and immiscible at higher temperatures.
• Composition M The same ester used in Composition K was mixed with the same refrigerant blend of Composition L and found to be miscible at -50°C and +61°C but immiscible at higher temperatures.
• Composition N The technical grade pentaerythritol ester of the acid mixture of Composition J was mixed with the same refrigerant blend of Composition L and found to be miscible at -50°C and +32°C, but immiscible at higher temperatures.

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• 1995
  • 1995-11-16 CA CA002181387A patent/CA2181387A1/en not_active Abandoned
  • 1995-11-16 WO PCT/US1995/014963 patent/WO1997019144A1/en not_active Application Discontinuation
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  • 1995-11-16 AU AU41642/96A patent/AU4164296A/en not_active Abandoned
  • 1995-11-16 CN CN95191673A patent/CN1177371A/zh active Pending
  • 1995-11-16 EP EP95940024A patent/EP0804517A1/de not_active Withdrawn
  • 1995-11-16 NZ NZ296904A patent/NZ296904A/en unknown
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