Patent Grant
9803122
The present invention relates to a refrigeration oil composition including a polyol ester oil which is soluble with either hydrofluorocarbon-based refrigerants or hydrocarbon-based refrigerants.
A refrigeration oil composition obtained by dissolving a refrigerant in a refrigeration oil is used as a working fluid in the refrigeration cycle in automotive air conditioners, domestic air conditioners, air conditioning within buildings, cold storehouses, refrigerators, and the like, and hydrofluorocarbon-based refrigerants which contain no chlorine and are constituted of hydrogen, carbon, and fluorine are in use from the standpoint of environmental conservation. Polyol ester oils are used accordingly as refrigeration oils for dissolving the hydrofluorocarbon-based refrigerants therein (see, for example, patent document 1).
However, even refrigeration oil compositions containing the same hydrofluorocarbon-based refrigerant usually differ in requirements concerning the temperature at which the composition separates into the refrigeration oil and the refrigerant (two-layer separation temperature), kinematic viscosity, etc. depending on applications or purposes. Although it is generally necessary to lower the kinematic viscosity of a polyol ester oil for increasing the solubility of a hydrofluorocarbon-based refrigerant therein, the reduced kinematic viscosity results in a decrease in the lubricity of the refrigeration oil composition. Meanwhile, in cases when the lubricity is improved by heightening the kinematic viscosity of the polyol ester oil, the hydrofluorocarbon-based refrigerant comes to separate out.
There are hence cases where a polyol ester oil which is excellent in terms of the solubility of hydrofluorocarbon-based refrigerants therein and a polyol ester oil having excellent lubricity are mixed with each other and used so as to result in solubility and kinematic viscosity that are suitable for the application or purpose (see, for example, patent documents 2 and 3). However, in case where the two polyol ester oils differ considerably in solubility with refrigerants, the polyol ester oil which is less soluble in the refrigerant gradually separates out, depending on the refrigerant used, during the period when the refrigeration oil composition circulates in the refrigeration cycle.
Meanwhile, since hydrofluorocarbon-based refrigerants have an exceedingly high global warming potential, hydrocarbon-based refrigerants, which are considerably low in global warming potential although flammable, are employed in some applications. There is a possibility that such hydrocarbon-based refrigerants might be increasingly used in various applications in future so long as apparatus modification measures are taken to cope with the problem concerning flammability. As refrigeration oils for dissolving hydrocarbon-based refrigerants therein, use has been mainly made of naphthenic or paraffinic mineral oils, alkylbenzene oils, ether oils, fluorinated oils, and the like. However, polyol ester-based lubricating oils having come to be used for the purpose of further improving lubricity. For example, an ester oil which is an ester of a neopentyl polyol including neopentyl glycol or pentaerythritol with a branched monovalent fatty acid having 7 to 9 carbon atoms (see patent document 4) and a polyol ester oil having an alkyl group having 11 to 19 carbon atoms (see patent document 5) are in use.
However, as in the case of hydrofluorocarbon-based refrigerants, such refrigeration oils usually differ in requirements concerning two-layer separation temperature, kinematic viscosity, etc. depending on the applications or purposes of the apparatus to be used. In addition, since hydrocarbon-based refrigerants have an exceedingly low density which is about one-half the density of hydrofluorocarbon-based refrigerants, the volume concentration of a hydrocarbon-based refrigerant dissolved in a refrigeration oil even in the same weight concentration as before is twice and the viscosity, which is influenced by volume concentration, is considerably lower than the conventional refrigerant-solution viscosity. This decrease in refrigerant-solution viscosity is a factor which causes a decrease in lubricity. In the case of using a refrigerant and a refrigeration oil which have high solubility with each other, the refrigeration oil to be used is required to have high kinematic viscosity from the standpoint of heightening the refrigerant-solution viscosity. However, since the refrigerant and the refrigeration oil considerably differ in density and because the refrigeration oil having too high a viscosity has impaired flowability, the refrigerant and the refrigeration oil are less apt to mingle with each other in an actual machine, resulting in a possibility that the refrigeration oil might be supplied in a reduced amount to the surfaces to be lubricated and the lubricity be impaired rather than improved.
However, the refrigeration oil described in patent document 4 has a low viscosity (about 10 to 32 mm2/s at 40° C. according to Examples) and may raise difficulties when used in large refrigerated facilities. Furthermore, the refrigeration oil described in patent document 5 is intended to be used with R290, and is usable only in limited applications.
Meanwhile, in production sites for producing refrigeration oils, it is necessary that many kinds of polyol ester oils produced from a large number of raw materials are ready for use so as to be capable of coping with differences in applications or purposes and in the kinds of hydrofluorocarbon-based refrigerants, and this has resulted in complexation of procurement of raw materials, production management, and product control. The polyol ester oils described in patent documents 2 and 3 also are each intended to be suited for specific refrigerants and specific apparatus, and when used in combination with other refrigerants or in other apparatus, show too high or too low solubility with the refrigerants or have too high or too low viscosity. In particular, it is impossible to obtain suitable solubility with less soluble refrigerants, such as difluoromethane (R-32) refrigerant, while ensuring necessary viscosity.
The same applies to hydrocarbon-based refrigerants. Although it is necessary that many kinds of refrigeration oils produced from a large number of raw materials are ready, the current prior-art techniques including patent documents 4 and 5 are ineffective in overcoming such problems.
Patent Document 1: Japanese Patent No. 2787083
Patent Document 2: Japanese Patent No. 3510888
Patent Document 3: JP-A-2010-235960
Patent Document 4: Japanese Patent No. 3909744
Patent Document 5: JP-A-2010-31134
An object of the invention, which has been achieved in view of the circumstances described above, is to provide a refrigeration oil composition which eliminates the necessity of making many kinds of refrigeration oils or raw materials therefor ready for coping with differences in applications or purposes and in the kinds of refrigerants and which not only is free from separation between oils that have been mixed together, but also is made to have solubility and viscosity that are suitable for any of various hydrofluorocarbon-based refrigerants or hydrocarbon-based refrigerants and for any of various refrigerated facilities, by changing the ratio of specific raw materials.
In order to accomplish the object, the present invention provides the following refrigeration oil compositions.
(1) A refrigeration oil composition including a polyol ester oil which is soluble with either a hydrofluorocarbon-based refrigerant or a hydrocarbon-based refrigerant,
wherein the polyol ester oil is a product of the esterification of an alcohol ingredient including pentaerythritol and dipentaerythritol and a fatty acid ingredient including at least one of a linear or branched fatty acid having 5 carbon atoms and a linear or branched fatty acid having 6 carbon atoms and including at least one of a linear or branched fatty acid having 8 carbon atoms and a linear or branched fatty acid having 9 carbon atoms,
at least one of the linear or branched fatty acid having 5 carbon atoms and linear or branched fatty acid having 6 carbon atoms in the fatty acid ingredient accounts for 20 to 100% by mol of the total amount of the fatty acid ingredient, and
either the alcohol ingredient or the fatty acid ingredient is a mixture composed of two components.
(2) The refrigeration oil composition according to (1) above,
wherein at least one of the fatty acids which constitute the fatty acid ingredient is a branched fatty acid.
(3) The refrigeration oil composition according to (1) above,
wherein the fatty acid ingredient is a mixture of: at least one of 2-methylbutanoic acid and 2-methylpentanoic acid; and at least one of 2-ethylhexanoic acid and 3,5,5-trimethylhexanoic acid.
(4) The refrigeration oil composition according to (1) above,
wherein the fatty acid ingredient is a mixture of 2-methylbutanoic acid and 2-ethylhexanoic acid.
(5) The refrigeration oil composition according to any one of (1) to (4) above,
wherein the hydrofluorocarbon-based refrigerant includes at least one member selected from R-32, R-410A, HFO-1234yf, and HFO-1234ze(E).
(6) The refrigeration oil composition according to any one of (1) to (4) above,
wherein the hydrocarbon-based refrigerant including at least one member selected from R-290, R-600a, and R-1270.
(7) The refrigeration oil composition according to any one of (1) to (6) above, having a low-temperature-side two-layer separation temperature and a high-temperature-side two-layer separation temperature, with respect to separation from the hydrofluorocarbon-based refrigerant or hydrocarbon-based refrigerant as measured at an oil content of 20% by weight, of +20 degrees or lower and +35 degrees or higher, respectively.
(8) The refrigeration oil composition according to any one of (1) to (7) above, containing at least one of an antioxidant, an epoxy-compound acid scavenger, and an extreme-pressure agent.
In the refrigeration oil composition of the invention, the polyol ester oil is a product of the esterification of a specific alcohol ingredient and a specific fatty acid ingredient, and has, in the molecule, both a component having excellent solubility with the hydrofluorocarbon-based refrigerant or hydrocarbon-based refrigerant and a component having excellent lubricity. Because of this, the refrigeration oil composition is free from the separation between oils which occurs in the presence of a refrigerant due to a difference therebetween in solubility with the refrigerant, as in the case where a plurality of polyol ester oils are used as a mixture thereof. In addition, the polyol ester oil does not separate from the hydrofluorocarbon-based refrigerant or hydrocarbon-based refrigerant to stagnate in the refrigerating circuit. Since this refrigeration oil is made to have solubility and viscosity that are suitable for any of various hydrofluorocarbon-based refrigerants or hydrocarbon-based refrigerants and for any of various refrigerated facilities, by changing the ratio of specific raw materials, the refrigeration oil composition can satisfactorily and stably exhibit the lubricating performance and cooling performance in refrigerated facilities.
Furthermore, the same alcohols and the same fatty acids can be used in common for constituting the specific alcohol ingredient and the specific fatty acid ingredient, respectively, regardless of the kind of the hydrofluorocarbon-based refrigerant or hydrocarbon-based refrigerant. Consequently, it is not necessary that raw materials for the polyol ester oil are prepared for each refrigerant, as in conventional techniques, and the complexity of procurement of raw materials and production management can be reduced.
The refrigeration oil composition of the invention includes a polyol ester oil. As the polyol ester oil, use is made of a product of the esterification of an alcohol ingredient including pentaerythritol and dipentaerythritol and a fatty acid ingredient including at least one of a linear or branched fatty acid having 5 carbon atoms and a linear or branched fatty acid having 6 carbon atoms and including at least one of a linear or branched fatty acid having 8 carbon atoms and a linear or branched fatty acid having 9 carbon atoms. It is, however, noted that either the alcohol ingredient or the fatty acid ingredient is a mixture composed of two components. Meanwhile, since a fatty acid can be present as a racemate, a substance which is one fatty acid but is a racemate is regarded as two kinds of fatty acids. This polyol ester oil can be synthesized so as to be applicable to any of various hydrofluorocarbon refrigerants or hydrocarbon-based refrigerants which differ in solubility and to any of various refrigerated facilities which differ in required kinematic viscosity, by merely changing the ratio of components with respect to a specific combination of components of the alcohol ingredient and fatty acid ingredient as raw materials.
Pentaerythritol and dipentaerythritol, which are used as the alcohol ingredient, give an esterification product that not only has lubricity but also is less apt to undergo influences of moisture, the susceptibility to which is a drawback of ester compounds, and has exceedingly high hydrolytic resistance. Furthermore, the solubility with the hydrofluorocarbon-based refrigerant or hydrocarbon-based refrigerant and the affinity for metal surfaces can be regulated by selecting the kinds of the fatty acids to be used for the esterification. Since dipentaerythritol is a dimer of pentaerythritol, a combination thereof with pentaerythritol brings about excellent stability. By regulating the proportion of the pentaerythritol to the dipentaerythritol, the viscosity of the lubricating oil can be set to a value required by a refrigerated facility. Furthermore, by regulating the high-temperature-side two-layer separation temperature to a more suitable value, lubricity within the compressor can be ensured.
The fatty acid ingredient is configured of at least one of a linear or branched fatty acid having 5 carbon atoms (hereinafter inclusively referred to as “pentanoic acid”) and a linear or branched fatty acid having 6 carbon atoms (hereinafter inclusively referred to as “hexanoic acid”) and containing a linear or branched fatty acid having 8 carbon atoms (hereinafter inclusively referred to as “octanoic acid”) and a linear or branched fatty acid having 9 carbon atoms (hereinafter inclusively referred to as “nonanoic acid”).
At least one of the pentanoic acid and hexanoic acid is a fatty acid ingredient for improving solubility with the refrigerant. Although a fatty acid ingredient having a smaller number of carbon atoms is more effective in improving solubility, use is made of the fatty acid(s) having 5 or 6 carbon atoms in order to ensure hydrolytic stability and viscosity to some degree. From the standpoint of ensuring the solubility of the polyol ester oil with refrigerant R-32, which is especially poorly soluble, the upper limit of the length of the carbon chain in this ingredient is 5 in terms of the number of carbon atoms; normal pentanoic acid is applicable but normal hexanoic acid is undesirable. This fatty acid serves also as an ingredient for regulating viscosity and ensuring lubricity, and heightens the polarity of the molecule to thereby reduce solubility and improve the affinity for metal surfaces.
At least one of the octanoic acid and nonanoic acid is a fatty acid ingredient for ensuring viscosity and lubricity and for improving solubility with the refrigerant. A fatty acid ingredient having a larger number of carbon atoms is more effective in improving viscosity and has reduced polarity to improve solubility. However, in view of a decrease in solubility and from the standpoint of ensuring low-temperature flowability and oxidative stability, use is made of the fatty acid(s) having 8 or 9 carbon atoms, which has been actually used for conventional refrigeration oils.
Especially from the standpoints of reducing adverse influences on solubility and improving hydrolytic stability and viscosity, the branched fatty acids are more preferred. Consequently, the branched form of each acid is more effective than the linear form thereof in enhancing the solubility of the hydrofluorocarbon-based refrigerant or hydrocarbon-based refrigerant and is capable of further lowering the low-temperature-side two-layer separation temperature. Furthermore, since the branched form is more effective in heightening viscosity than the linear form, use of the branched form facilitates the setting of viscosity to that required by a refrigerated facility. In addition, the branched form is capable of more improving hydrolytic stability than the linear form. Consequently, a combination of fatty acid components which constitute the fatty acid ingredient and in which at least one is the branched form is preferred to a combination in which all the fatty acids are linear. Most preferred of such combinations is one in which all the fatty acids are branched.
The branched chains of the fatty acids preferably are methyl group or ethyl group, and it is preferable that the number of branches in each branched fatty acid is 1 to 3. Furthermore, a preferred branching position is the 2-position, i.e., the position adjacent to the carboxyl group. Preferred of such branched fatty acids are 2-methylbutanoic acid as a branched pentanoic acid, 2-methylpentanoic acid as a branched hexanoic acid, 2-ethylhexanoic acid as a branched octanoic acid, and 3,5,5-trimethylhexanoic acid as a branched nonanoic acid. Consequently, preferred as the fatty acid ingredient are mixtures of: at least one of 2-methylbutanoic acid and 2-methylpentanoic acid; and at least one of 2-ethylhexanoic acid and 3,5,5-trimethylhexanoic acid. Especially preferred is a mixture of 2-methylbutanoic acid and 2-ethylhexanoic acid.
In the invention, the kinematic viscosity of the polyol ester oil is 15 to 350 mm2/s (40° C.), and is suitably selected in accordance with the apparatus in which the refrigeration oil composition is to be used and with applications. Especially for air conditioners, it is preferable that the kinematic viscosity of the polyol ester oil is 46 to 100 mm2/s (40° C.). Kinematic viscosities thereof less than 46 mm2/s (40° C.) result in poor lubricity, while kinematic viscosities thereof exceeding 100 mm2/s (40° C.) result in too high viscosity resistance and a considerable decrease in performance. A more preferred range of the kinematic viscosity thereof is 50 to 80 mm2/s (40° C.). For small refrigerated facilities, it is preferable that the kinematic viscosity of the polyol ester oil is 22 to 68 mm2/s (40° C.). Kinematic viscosities thereof less than 22 mm2/s (40° C.) result in poor lubricity, while kinematic viscosities thereof exceeding 68 mm2/s (40° C.) result in too high viscosity resistance and a considerable decrease in performance. A more preferred range of the kinematic viscosity thereof is 30 to 50 mm2/s (40° C.). For large refrigerated facilities, it is preferable that the kinematic viscosity of the polyol ester oil is 68 to 320 mm2/s (40° C.). Kinematic viscosities thereof less than 68 mm2/s (40° C.) result in poor lubricity or poor compression chamber-sealing properties, while kinematic viscosities thereof exceeding 320 mm2/s (40° C.) result in too high viscosity resistance and a considerable decrease in performance. Since refrigerated facilities differ markedly in required kinematic viscosity depending on the compressor and refrigeration system, it is necessary that the polyol ester oil is regulated so as to have the kinematic viscosity required by a refrigerated facility. Such a kinematic viscosity may be attained by regulating the proportion in which pentaerythritol and dipentaerythritol are mixed together; pentaerythritol is used in an amount of 10 to 90% by mol based on the whole alcohol ingredient, with the remainder being dipentaerythritol. In the case where it is necessary that a plurality of polyol ester oils which each are the polyol ester oil of the invention and which differ in kinematic viscosity are mixed with each other, the resultant mixture can be used without suffering separation between the oils so long as the solubility of each polyol ester oil with the refrigerant to be used is appropriate. Especially for air conditioners, it is preferred to employ such a proportion that the amount of pentaerythritol is 40 to 80% by mol based on the whole alcohol ingredient, with the remainder being dipentaerythritol. For small refrigerated facilities, it is preferred to employ such a proportion that the amount of pentaerythritol is 60 to 90% by mol based on the whole alcohol ingredient, with the remainder being dipentaerythritol. For large refrigerated facilities, it is preferred to employ such a proportion that the amount of pentaerythritol is 10 to 40% by mol based on the whole alcohol ingredient, with the remainder being dipentaerythritol.
Meanwhile, the hydrofluorocarbon-based refrigerant to be dissolved in the refrigeration oil composition is not particularly limited, and one which has conventionally been used as a refrigerant can be used, such as, for example, R-134a (tetrafluoroethane) or R-410A (a mixture of difluoromethane and pentafluoroethane). It is, however, noted that requirements for environmental conservation are becoming severer and, especially in Europe, it was decided to use HFO-1234yf (2,3,3,3-tetrafluoro-1-propene) as a new refrigerant in the automotive air conditioners of motor vehicles manufactured in and after the year 2011 (2nd International Workshop on Mobile Air Conditioning and Auxiliary Systems-Trono, Italy Nov. 29, 2007 and European Automotive A/C Convention, Sep. 22-23, 2008). Besides that refrigerant, the following are receiving attention as next-generation refrigerants: HFO-1234ze(E) (trans-1,3,3,3-tetrafluoro-1-propene), R-32 (difluoromethane), a mixture of HFO-1234yf (2,3,3,3-tetrafluoro-1-propene) and R-32 (difluoromethane), and a mixture of HFO-1234ze(E) (trans-1,3,3,3-tetrafluoro-1-propene) and R-32 (difluoromethane). In the invention also, it is preferred to use HFO-1234yf, HFO-1234ze(E), or R-32 as the hydrofluorocarbon-based refrigerant. Any one of these refrigerants and R-410A, which is a refrigerant used hitherto, may be used alone, or two or more thereof may be used as a mixture thereof. In particular, R-32 is receiving attention as a next-generation refrigerant since R-32 has a low global warming potential (GWP), is not a mixed refrigerant, and is relatively inexpensive. However, this refrigerant has low solubility with conventional polyol ester oils and are prone to cause two-layer separation. According to the invention, however, by regulating the components of the alcohol ingredient and of the fatty acid ingredient and regulating the mixing proportions thereof, a refrigeration oil composition which is prevented from undergoing two-layer separation and has satisfactory lubricity is obtained even when R-32 is used.
The hydrocarbon-based refrigerant also is not limited, and use can be made of any one of hydrocarbon-based refrigerants which have hitherto been used in some appliances, such as, for example, R-600a, R-290 (propane), and R-1270 (propylene), or a mixture of two or more thereof. In particular, R-290 is receiving attention as a next-generation refrigerant since R-290 has a low global warming potential (GWP), is not a mixed refrigerant, and is relatively inexpensive. However, this refrigerant has too high solubility with conventional naphthenic mineral oils to cause a decrease in viscosity due to the diluting effect of the refrigerant and is hence prone to cause a decrease in lubricity. According to the invention, however, by regulating the components of the alcohol ingredient and of the fatty acid ingredient and regulating the mixing proportions thereof, a refrigeration oil composition having satisfactory lubricity is obtained using R-290.
In order to produce the refrigeration oil composition of the invention, a hydrofluorocarbon-based refrigerant or a hydrocarbon-based refrigerant is selected first. Thereafter, the mixing proportion of pentaerythritol to dipentaerythritol, the mixing proportion of at least one of pentanoic acid and hexanoic acid to at least one of octanoic acid and nonanoic acid, and the mixing proportion of the alcohol ingredient to the fatty acid ingredient are set while taking account of solubility with the selected refrigerant and lubricity, and the alcohol ingredient is subjected to esterification reaction with the fatty acid ingredient to produce a polyol ester oil.
In the refrigeration oil composition, it is preferable that with respect to separation from the hydrofluorocarbon-based refrigerant or hydrocarbon-based refrigerant, the high-temperature-side two-layer separation temperature is +35° C. or higher, in particular, in the range of +40 to +65° C., and the low-temperature-side two-layer separation temperature is +20° C. or lower, in particular, 0° C. or lower. For use in refrigerated facilities or large air conditioners, there is a request for −30° C. or lower, or for −50° C. or lower. Such solubility can be obtained by regulating the mixing proportion of at least one of the pentanoic acid and hexanoic acid to at least one of the octanoic acid and nonanoic acid in the fatty acid ingredient. Specifically, the amount of at least one of pentanoic acid and hexanoic acid is regulated to 20 to 100% by mol based on the whole fatty acid ingredient, with the remainder being at least one of octanoic acid and nonanoic acid. Especially for domestic air conditioners in which R-32 is used, a preferred proportion is one in which 2-methylbutanoic acid is used in an amount of 40 to 60% by mol, with the remainder being 2-ethylhexanoic acid.
In case where the high-temperature-side two-layer separation temperature is not +35° C. or higher and the low-temperature-side two-layer separation temperature is not +20° C. or lower, the solubility between the polyol ester oil and the hydrofluorocarbon-based refrigerant or hydrocarbon-based refrigerant is insufficient and separation between the two occurs in high-temperature parts of the refrigeration cycle, e.g., the condenser, and in low-temperature parts thereof, e.g., the evaporator. Once the separation occurs, the following adverse influences are exerted thereby: the polyol ester oil stagnates in heat exchangers, such as the condenser and the evaporator, to inhibit heat exchange; the amount of the polyol ester oil which returns to the compressor decreases to cause compressor troubles due to insufficient lubrication; and the separation inhibits refrigerant circulation to thereby considerably lower the cooling performance. Incidentally, any polyol ester oil produced from one alcohol and one fatty acid is prone to crystallize or solidify at room temperature to low temperatures and hence cannot be adopted. In addition, it is noted that in cases when a fatty acid which is apparently constituted of one component but is a racemate is employed, this fatty acid is regarded as being constituted of two components. Consequently, 2-methylbutanoic acid, which is a pentanoic acid, is more effective in preventing crystallization than 3-methylbutanoic acid, which also is a pentanoic acid, and 2-methylpentanoic acid, which is a hexanoic acid, is more effective in preventing crystallization, than 2-ethylbutanoic acid, which also is a hexanoic acid.
In particular, for refrigerated facilities or large air conditioners in which R-32 is used, a preferred proportion is one in which 2-methylbutanoic acid is used in an amount of 60 to 90% by mol, with the remainder being 2-ethylhxanoic acid. For refrigerated facilities in which HFO-1234ze(E) is used, preferred are a proportion in which 2-methylbutanoic acid is used in an amount of 20 to 60% by mol, with the remainder being 2-ethylhexanoic acid, and a proportion in which 2-methylpentanoic acid is used in an amount of 20 to 60% by mol, with the remainder being 3,5,5-trimethylhexanoic acid.
There are no limitations on the esterification reaction, and the reaction can be conducted in accordance with methods in practical use. In the esterification reaction, the carboxyl groups of the fatty acids react with all the hydroxyl groups of the alcohols. Consequently, once the mixing proportion of pentaerythritol to dipentaerythritol in the alcohol ingredient is decided, the total amount of hydroxyl groups in the mixture is also determined and, hence, the amount of the fatty acid ingredient to be used may be set in accordance with the total amount of hydroxyl groups.
Processes for producing the refrigeration oil composition are specifically shown below. For example, in the case where HFO-1234ze(E) has been selected as a hydrofluorocarbon-based refrigerant for small refrigerated facilities and where the required kinematic viscosity at 40° C. is 15 to 60 mm2/s, then an alcohol ingredient in which pentaerythritol accounts for 60 to 100% by mol thereof, with the remainder being dipentaerythritol, and a fatty acid ingredient in which 2-methylbutanoic acid accounts for 20 to 90% by mol thereof, with the remainder being at least one of 2-ethylhexanoic acid and 3,5,5-trimethylhexanoic acid, are used and esterified to produce a polyol ester oil. Thereafter, HFO-1234ze(E) is dissolved in this polyol ester oil to obtain a refrigeration oil composition. The refrigeration oil composition thus obtained satisfies the high-temperature-side two-layer separation temperature, low-temperature-side two-layer separation temperature, and kinematic viscosity described above and is excellent in terms of refrigerating performance and lubricating performance.
Meanwhile, in the case where, for example, HFO-1234ze(E) has been selected for large refrigerated facilities and where the required kinematic viscosity at 40° C. is 90 to 240 mm2/s, then use is made of either a polyol ester oil obtained by esterifying an alcohol ingredient in which pentaerythritol accounts for 0 to 70% by mol thereof, with the remainder being dipentaerythritol, and a fatty acid ingredient in which at least one of 2-methylbutanoic acid and 2-methylpentanoic acid accounts for 20 to 60% by mol thereof, with the remainder being 2-ethylhexanoic acid, or a polyol ester oil obtained by esterifying an alcohol ingredient in which pentaerythritol accounts for 40 to 100% by mol thereof, with the remainder being dipentaerythritol, and a fatty acid ingredient in which at least one of 2-methylbutanoic acid and 2-methylpentanoic acid accounts for 20 to 60% by mol thereof, with the remainder being 3,5,5-trimethylhexanoic acid. HFO-1234ze(E) is dissolved in this polyol ester oil to obtain a refrigeration oil composition.
Furthermore, in the case where, for example, R-32 has been selected for domestic air conditioners and where the required kinematic viscosity at 40° C. is 40 to 80 mm2/s, then use is made of either a polyol ester oil obtained by esterifying an alcohol ingredient in which pentaerythritol accounts for 40 to 80% by mol thereof, with the remainder being dipentaerythritol, and a fatty acid ingredient in which 2-methylbutanoic acid accounts for 40 to 70% by mol thereof, with the remainder being 2-ethylhexanoic acid, or a polyol ester oil obtained by esterifying an alcohol ingredient in which pentaerythritol accounts for 50 to 100% by mol thereof, with the remainder being dipentaerythritol, and a fatty acid ingredient in which 2-methylbutanoic acid accounts for 30 to 70% by mol thereof, with the remainder being 3,5,5-trimethylhexanoic acid. R-32 is dissolved in this polyol ester oil to obtain a refrigeration oil composition.
Moreover, also in the case of a conventional mode in which R-410A is selected for domestic air conditioners, use can be made of a polyol ester oil obtained by esterifying an alcohol ingredient in which pentaerythritol accounts for 40 to 80% by mol thereof, with the remainder being dipentaerythritol, and a fatty acid ingredient in which 2-methylbutanoic acid accounts for 40 to 70% by mol thereof, with the remainder being 2-ethylhexanoic acid. R-410A is dissolved in this polyol ester oil to obtain a refrigeration oil composition.
Furthermore, also in the case of a conventional mode in which R-410A is selected for large air conditioners, use can be made of a polyol ester oil obtained by esterifying an alcohol ingredient in which pentaerythritol accounts for 40 to 80% by mol thereof, with the remainder being dipentaerythritol, and a fatty acid ingredient in which 2-methylbutanoic acid accounts for 40 to 60% by mol thereof, with the remainder being 2-ethylhexanoic acid. R-410A is dissolved in this polyol ester oil to obtain a refrigeration oil composition.
Moreover, also in the case where R-32, which is a next-generation refrigerant, and R-410A, which is a conventional refrigerant, mingle with each other in a large air conditioner because of, for example, the configuration of the facilities, use can be made of a polyol ester oil obtained by esterifying an alcohol ingredient in which pentaerythritol accounts for 40 to 80% by mol thereof, with the remainder being dipentaerythritol, and a fatty acid ingredient in which 2-methylbutanoic acid accounts for 40 to 60% by mol thereof, with the remainder being 2-ethylhexanoic acid. A mixed refrigerant composed of R-32 and R-410A is dissolved in this polyol ester oil to obtain a refrigeration oil composition.
Furthermore, in the case where a mixed refrigerant composed of R-32 and either HFO-1234yf or HFO-1234ze(E) has been selected for domestic air conditioners and where the required kinematic viscosity at 40° C. is 40 to 80 mm2/s, then use is made of either a polyol ester oil obtained by esterifying an alcohol ingredient in which pentaerythritol accounts for 40 to 80% by mol thereof, with the remainder being dipentaerythritol, and a fatty acid ingredient in which 2-methylbutanoic acid accounts for 20 to 50% by mol thereof, with the remainder being 2-ethylhexanoic acid, or a polyol ester oil obtained by esterifying an alcohol ingredient in which pentaerythritol accounts for 50 to 100% by mole thereof, with the remainder being dipentaerythritol, and a fatty acid ingredient in which 2-methylbutanoic acid accounts for 30 to 70% by mol thereof, with the remainder being 3,5,5-trimethylhexanoic acid. A mixed refrigerant composed of R-32 and either HFO-1234yf or HFO-1234ze(E) is dissolved in the polyol ester oil to obtain a refrigeration oil composition.
Furthermore, in the case where R-290 has been selected as a hydrocarbon-based refrigerant for small refrigerated facilities and where the required kinematic viscosity at 40° C. is 15 to 60 mm2/s, then an alcohol ingredient in which pentaerythritol accounts for 60 to 100% by mol thereof, with the remainder being dipentaerythritol, and a fatty acid ingredient in which 2-methylbutanoic acid accounts for 20 to 90% by mol thereof, with the remainder being at least one of 2-ethylhexanoic acid and 3,5,5-trimethylhexanoic acid, are used and esterified to produce a polyol ester oil. Such a refrigeration oil composition satisfies the high-temperature-side two-layer separation temperature, low-temperature-side two-layer separation temperature, and kinematic viscosity described above and is excellent in terms of refrigerating performance and lubricating performance.
Furthermore, in the case where, for example, R-1270 has been selected for large refrigerated facilities and where the required kinematic viscosity at 40° C. is 90 to 240 mm2/s, then use is made of either a polyol ester oil obtained by esterifying an alcohol ingredient in which pentaerythritol accounts for 0 to 70% by mole thereof, with the remainder being dipentaerythritol, and a fatty acid ingredient in which at least one of 2-methylbutanoic acid and 2-methylpentanoic acid accounts for 20 to 60% by mol thereof, with the remainder being 2-ethylhexanoic acid, or a polyol ester oil obtained by esterifying an alcohol ingredient in which pentaerythritol accounts for 40 to 100% by mol thereof, with the remainder being dipentaerythritol, and a fatty acid ingredient in which at least one of 2-methylbutanoic acid and 2-methylpentanoic acid accounts for 20 to 60% by mol thereof, with the remainder being 3,5,5-trimethylhexanoic acid.
Furthermore, in the case where, for example, R-290 has been selected for domestic air conditioners and where the required kinematic viscosity at 40° C. is 40 to 80 mm2/s, then use is made of either a polyol ester oil obtained by esterifying an alcohol ingredient in which pentaerythritol accounts for 40 to 80% by mol thereof, with the remainder being dipentaerythritol, and a fatty acid ingredient in which 2-methylbutanoic acid accounts for 40 to 70% by mol thereof, with the remainder being 2-ethylhexanoic acid, or a polyol ester oil obtained by esterifying an alcohol ingredient in which pentaerythritol accounts for 50 to 100% by mol thereof, with the remainder being dipentaerythritol, and a fatty acid ingredient in which 2-methylbutanoic acid accounts for 30 to 70% by mol thereof, with the remainder being 3,5,5-trimethylhexanoic acid.
Furthermore, in the case where, for example, a mixed refrigerant composed of R-290 and R-1270 has been selected for domestic air conditioners and where the required kinematic viscosity at 40° C. is 40 to 80 mm2/s, then use is made of either a polyol ester oil obtained by esterifying an alcohol ingredient in which pentaerythritol accounts for 40 to 80% by mol thereof, with the remainder being dipentaerythritol, and a fatty acid ingredient in which 2-methylbutanoic acid accounts for 20 to 50% by mol thereof, with the remainder being 2-ethylhexanoic acid, or a polyol ester oil obtained by esterifying an alcohol ingredient in which pentaerythritol accounts for 50 to 100% by mol thereof, with the remainder being dipentaerythritol, and a fatty acid ingredient in which 2-methylbutanoic acid accounts for 30-70% by mol thereof, with the remainder being 3,5,5-trimethylhexanoic acid.
As described above, by using pentaerythritol, dipentaerythritol, at least one of pentanoic acid and hexanoic acid, and at least one of octanoic acid and nonanoic acid in common and by merely changing the mixing proportions thereof, polyol ester oils which are usable with various hydrofluorocarbon-based refrigerants or hydrocarbon-based refrigerants are obtained. Consequently, to prepare pentaerythritol, dipentaerythritol, at least one of pentanoic acid and hexanoic acid, and at least one of octanoic acid and nonanoic acid beforehand suffices for the production site, and the complexation of raw material procurement and of production management can be significantly reduced as compared with the case where many kinds of polyol ester oils are prepared.
Various additives can be added to the refrigeration oil composition of the invention. The polyol ester oil has the possibility of undergoing oxidative deterioration or hydrolysis due to the outside air or moisture which has infiltrated into the refrigeration cycle or due to the influence of residues, e.g., a rust preventive, which remain in the refrigeration cycle, resulting in a possibility that an acidic component might be produced by the deterioration or hydrolysis to corrode the inside of the system. Furthermore, refrigerants having a double bond in the molecule, such as HFO-1234yf, HFO-1234ze(E), and R-1270, are more prone, than other hydrofluorocarbon-based refrigerants, to undergo oxidative deterioration or hydrolysis due to heat or the outside air or moisture which has infiltrated into the refrigeration cycle or due to the influence of residues, e.g., a rust preventive, which remain in the refrigeration cycle, resulting in a possibility that an acidic component might be produced by the deterioration or hydrolysis to corrode the inside of the system. It is therefore preferred to add an epoxy-compound acid scavenger. In particular, epoxy-compound acid scavengers such as glycidyl ethers and glycidyl esters are preferred since such compounds have a high acid-scavenging effect. Furthermore, it is preferred to use an epoxy-compound acid scavenger having an epoxycycloalkyl group or an epoxy-compound acid scavenger obtained by introducing a glycidyl group into an end of polypropylene glycol, from the standpoint of affinity for the polyol ester oil and hydrofluorocarbon-based refrigerant. Moreover, an epoxy-compound acid scavenger obtained by introducing a glycidyl group into an alcohol or fatty acid having 10 or less carbon atoms is preferred since this compound shows improved acid-scavenging ability due to the high dispersibility thereof in the hydrofluorocarbon-based refrigerant or hydrocarbon-based refrigerant.
By adding a lubricity improver, such as an extreme-pressure agent or an oiliness agent, not only the metallic surfaces of sliding portions can be prevented from wearing or seizing but also the lubricity is enhanced to reduce frictional heating, making it possible to inhibit the decomposition of refrigerants having a double bond in the molecule, such as HFO-1234yf, HFO-1234ze(E), and R-1270. As the extreme-pressure agent, use may be made of a phosphoric acid type extreme-pressure agent or a thiophosphoric acid type extreme-pressure agent in accordance with requirements of the refrigerated facility or air conditioner. Since thiophosphoric acid type extreme-pressure agents cause precipitation of a sulfur compound depending on the conditions and it is hence necessary to minimize the amount thereof if these agents are added, phosphoric acid type extreme-pressure agents are preferred. Examples of the phosphoric acid type extreme-pressure agents include tricresyl phosphate, triphenyl phosphate, tris(tert-butylphenyl)phosphate, monophenyl bis(tert-butylphenyl)phosphate, and diphenyl tert-butylphenyl phosphate. As the oiliness agent, use may be made of one which has no active element, e.g., phosphorus or sulfur, and which utilizes the affinity of oxygen for metals, such as a long-chain-alkyl alcohol, alkyl monoglyceride, or fatty acid methyl ester. Examples thereof include oleyl alcohol, isostearyl alcohol, oleyl monoglyceride, linolenyl monoglyceride, and methyl oleate.
It is also preferred to add an antioxidant in order to inhibit refrigerants having a double bond in the molecule, such as HFO-1234yf, HFO-1234ze(E), and R-1270, from decomposing or from undergoing oxidative deterioration due to the infiltration of outside air into the refrigeration cycle. Examples of the antioxidant include phenolic antioxidants such as 2,6-di-tert-butyl-4-methylphenol, 2,6-di-tert-butyl-4-ethylphenol, and 2,2′-methylenebis(4-methyl-6-tert-butylphenol) and amine-compound antioxidants such as phenyl-α-naphthylamine and N,N′-diphenyl-p-phenylenediamine. However, since the amine-compound antioxidants have reactivity with refrigerants having a double bond in the molecule, such as HFO-1234yf, HFO-1234ze(E), and R-1270, it is preferred to use these antioxidants in the refrigeration oil to be applied to other hydrofluorocarbon-based refrigerants or to hydrocarbon-based refrigerants.
Any one of the epoxy-compound acid scavenger, lubricity improver, and antioxidant may be used alone, or the three agents can be used in combination. There are no limitations on the amount of each agent to be added, so long as the effect thereof is produced. It is, however, preferable that the amounts of the epoxy-compound acid scavenger, lubricity improver, and antioxidant are 0.25 to 2% by mass, 0.5 to 4% by mass, and 0.1 to 1% by mass, respectively, based on the whole refrigeration oil composition. In case where the addition amount of each agent is less than the lower limit, the effect thereof cannot be sufficiently produced. Even when the amount of each agent is larger than the upper limit, not only the effect is not enhanced any more, but also the relative content of the polyol ester oil is low, resulting in poor lubricity.
In addition to those additives, additives in general use may be added for the purpose of improving performances other than those mentioned above.
Test Examples are shown below to further explain the invention, but the invention should not be construed as being limited by the following Examples in any way. Incidentally, Test A relates to refrigeration oil compositions for hydrofluorocarbon-based refrigerants, while Test B relates to refrigeration oil compositions for hydrocarbon-based refrigerants.
<Test A: Refrigeration Oil Compositions for Hydrofluorocarbon-Based Refrigerants>
The alcohol ingredients and fatty acid ingredients shown in Table A were esterified to produce polyol ester oils. In the table, PE represents pentaerythritol, DiPE represents dipentaerythritol, LPt represents normal pentanoic acid (a pentanoic acid), 2 MBu represents DL-2-methylbutanoic acid (a pentanoic acid), LHx represents normal hexanoic acid (a hexanoic acid), 2 MPt represents DL-2-methylpentanoic acid (a hexanoic acid), 2EBu represents 2-ethylbutanoic acid (a hexanoic acid), 2EHx represents a 2-ethylhexanoic acid (an octanoic acid), and TMHx represents 3,5,5-trimethylhexanoic acid (a nonanoic acid), and the mixing proportion of each alcohol ingredient to the fatty acid ingredient is in molar ratio. A poly(vinyl ether) oil (comparative oil 15A) which is currently in use as a refrigeration oil was added as a comparative oil besides ester oils produced from the alcohol ingredient and fatty acid ingredient. Furthermore, comparative oils 18A, 19A, and 20A were added as mixed oils. The refrigeration oil A used in the mixed oils is in use as a refrigeration oil for HFC refrigerators; this refrigeration oil is highly soluble with refrigerant R-32 but has too low viscosity to be used as such in the refrigerated facilities or air conditioners to which the invention is intended to be applied.
Each of the polyol ester oils and comparative oils was examined for kinematic viscosity at 40° C. and 100° C. The results of the measurement are shown in Tables 3 and 4.
Each polyol ester oil and R-32 were enclosed in a glass tube so as to result in an oil content of 20% by weight, and the glass tube was shaken to dissolve the R-32 in the polyol ester oil. After the dissolution, the glass tube was placed in a water bath and gradually heated to measure the temperature at which the even layer separated into an oil layer and a refrigerant layer (high-temperature-side two-layer separation temperature). Meanwhile, the glass tube was placed in a cooling chamber and gradually cooled to measure the temperature at which the even layer separated into an oil layer and a refrigerant layer (low-temperature-side two-layer separation temperature).
The results of the measurements and the kinematic viscosities are both shown in Table 5 to Table 7.
The high-temperature-side two-layer separation temperature and the low-temperature-side two-layer separation temperature were measured in the same manners as in Test Example 1A, except that R-410A was used as a hydrofluorocarbon-based refrigerant. The results of the measurements and the kinematic viscosities are both shown in Table 8 and Table 9.
The high-temperature-side two-layer separation temperature and the low-temperature-side two-layer separation temperature were measured in the same manners as in Test Example 1A, except that HFO-1234yf was used as a hydrofluorocarbon-based refrigerant. The results of the measurements and the kinematic viscosities are both shown in Table 10 to Table 12.
The high-temperature-side two-layer separation temperature and the low-temperature-side two-layer separation temperature were measured in the same manners as in Test Example 1A, except that HFO-1234ze(E) was used as a hydrofluorocarbon-based refrigerant. The results of the measurements and the kinematic viscosities are both shown in Table 13 to Table 15.
Examples 1A, 2A, 3A, 4A, and 8A and Comparative Example 1A, which is a current refrigeration oil for R-410A air conditioners, were evaluated with a Falex tester. The results thereof are shown in Table 16.
(Test Conditions)
Example 2A and Comparative Example 1A, which is a current refrigeration oil for R-410A air conditioners, were evaluated through a hygroscopicity test. The results thereof are shown in Table 17.
(Test Conditions)
Test apparatus: A hygroscopicity tester based on a combination of a humidifier, acrylic case, turntable, fan, heater, hygrometer, and thermometer was produced and used.
Test temperature: 30° C.
Test humidity: 80% RH
Surface area of specimen: 21.2 cm2
The open time which was supposed when facility dealers handled refrigeration oils was set at 0.5 to 3 hours among the test periods shown in Table 17, and refrigeration oils were compared in the degree of moisture absorption in a range including shorter and longer periods. The results thereof are shown in
A polyol ester oil which had a moisture content of 500 ppm and to which an antioxidant and an acid scavenger had been added as additives was enclosed in a glass tube together with refrigerant R-32 and an iron wire, copper wire, or aluminum wire as a catalyst, and a heating test was conducted for 14 days in a 175° C. thermostatic chamber. After completion of the heating period, the contents were examined for appearance, color, any change in the catalyst, and precipitate. Furthermore, the polyol ester oil which had undergone the test was taken out and examined for acid value. The results thereof are shown in Table 18 and Table 19.
Density, color, flash point, pour point, kinematic viscosity, viscosity index, and total acid number, as properties required of refrigeration oils, are shown in Table 20 to Table 24 on the basis of Examples and Comparative Examples.
(List of Polyol Ester Oils for Each Raw Material Combination)
The Examples and the Comparative Examples are arranged with respect to each of raw material combinations to show that various viscosities and solubility with various refrigerants are obtained by changing the ratio of raw materials. The relationships between the raw material combination and kinematic viscosity or refrigerated facilities/air conditioners to which the oil is applicable are as shown in the following Table 25 to Table 34.
The relationship between each raw material combination and the solubility with each refrigerant (low-temperature-side two-layer separation temperature) is as shown in the following Table 35 to Table 44.
As shown in Table 23 to Table 32, the polyol ester oils each produced by esterifying an alcohol ingredient obtained by mixing pentaerythritol with dipentaerythritol and a fatty acid ingredient composed of at least one of pentanoic acid and hexanoic acid and at least one of octanoic acid and nonanoic acid are made to have various values of viscosity by changing the proportions of the raw materials with respect to each of specific raw material combinations.
Furthermore, as shown in Test Examples 1A to 4A and Table 33 to Table 42, refrigeration oil compositions which are excellent in terms of solubility and lubricity can be produced by using polyol ester oils each produced by esterifying an alcohol ingredient obtained by mixing pentaerythritol with dipentaerythritol and a fatty acid ingredient composed of at least one of pentanoic acid and hexanoic acid and at least one of octanoic acid and nonanoic acid, in accordance with the kinds of hydrofluorocarbon-based refrigerants. Moreover, as shown in Test Examples 5A to 8A, the polyol ester oils produced are equal or superior to conventional refrigeration oils in other performances and, by incorporating additives thereinto as in conventional products, the polyol ester oils can be rendered usable also in refrigerated facilities employing refrigerants having a low global warming potential, such as refrigerant R-32, as in apparatus in which R-410A, a conventional refrigerant, is used.
<Test B: Refrigeration Oil Compositions for Hydrocarbon-Based Refrigerants>
The alcohol ingredients and fatty acid ingredients shown in Table B were esterified to produce polyol ester oils. In the table, PE represents pentaerythritol, DiPE represents dipentaerythritol, LPt represents normal pentanoic acid (a pentanoic acid), 2 MBu represents DL-2-methylbutanoic acid (a pentanoic acid), LHx represents normal hexanoic acid (a hexanoic acid), 2 MPt represents DL-2-methylpentanoic acid (a hexanoic acid), 2EBu represents 2-ethylbutanoic acid (a hexanoic acid), 2EHx represents a 2-ethylhexanoic acid (an octanoic acid), and TMHx represents 3,5,5-trimethylhexanoic acid (a nonanoic acid), and the mixing proportion of each alcohol ingredient to the fatty acid ingredient is in molar ratio. A mineral oil (comparative oil 15B) for refrigerant R-290 was also used as a comparative oil.
Each of the polyol ester oils and comparative oils was examined for kinematic viscosity at 40° C. and 100° C. The results of the measurement are shown in Tables 47 and 48.
Each polyol ester oil and R-290 were enclosed in a glass tube so as to result in an oil content of 20% by weight, and the glass tube was shaken to dissolve the R-290 in the polyol ester oil. After the dissolution, the glass tube was placed in a water bath and gradually heated to measure the temperature at which the even layer separated into an oil layer and a refrigerant layer (high-temperature-side two-layer separation temperature). Meanwhile, the glass tube was placed in a cooling chamber and gradually cooled to measure the temperature at which the even layer separated into an oil layer and a refrigerant layer (low-temperature-side two-layer separation temperature). The results of the measurements and the kinematic viscosities are both shown in Table 49 to Table 51.
The high-temperature-side two-layer separation temperature and the low-temperature-side two-layer separation temperature were measured in the same manners as in Test Example 1B, except that R-600a was used as a hydrocarbon-based refrigerant. The results of the measurements and the kinematic viscosities are both shown in Table 52 and Table 53.
The high-temperature-side two-layer separation temperature and the low-temperature-side two-layer separation temperature were measured in the same manners as in Test Example 1B, except that R-1270 was used as a hydrocarbon-based refrigerant. The results of the measurements and the kinematic viscosities are both shown in Table 54 to Table 56.
Examples 1B, 2B, 3B, 4B, and 8B and Comparative Example 1B were evaluated with a Falex tester. The results thereof are shown in Table 57.
(Test Conditions)
Test apparatus: Falex tester (PIN-VEE BLOCK)
Test temperature: 80° C.
Test load: 150 lbs
Test period: 4 hr
Rotation speed: 290 rpm
Example 2B and Comparative Example 1B were evaluated through a hygroscopicity test. The results thereof are shown in Table 58.
(Test Conditions)
Test apparatus: A hygroscopicity tester based on a combination of a humidifier, acrylic case, turntable, fan, heater, hygrometer, and thermometer was produced and used.
Test temperature: 30° C.
Test humidity: 80% RH
Surface area of specimen: 21.2 cm2
The open time which was supposed when facility dealers handled refrigeration oils was set at 0.5 to 3 hours among the test periods shown in Table 58, and refrigeration oils were compared in the degree of moisture absorption in a range including shorter and longer periods. The results thereof are shown in
A polyol ester oil which had a moisture content of 500 ppm and to which an antioxidant and an acid scavenger had been added as additives was enclosed in a glass tube together with refrigerant R-290 and an iron wire, copper wire, or aluminum wire as a catalyst, and a heating test was conducted for 14 days in a 175° C. thermostatic chamber. After completion of the heating period, the contents were examined for appearance, color, any change in the catalyst, and precipitate. Furthermore, the polyol ester oil which had undergone the test was taken out and examined for acid value. The results thereof are shown in Table 59 and Table 60.
Density, color, flash point, pour point, kinematic viscosity, viscosity index, and total acid number, as properties required of refrigeration oils, are shown in Table 61 to Table 65 on the basis of Examples and Comparative Examples.
(List of Polyol Ester Oils for Each Raw Material Combination)
The Examples and the Comparative Examples are arranged with respect to each of raw material combinations to show that various viscosities and solubility with various refrigerants are obtained by changing the ratio of raw materials. The relationships between the raw material combination and kinematic viscosity or refrigerated facilities/air conditioners to which the oil is applicable are as shown in the following Table 66 to Table 75.
The relationship between each raw material combination and the solubility with each refrigerant (low-temperature-side two-layer separation temperature) is as shown in the following Table 76 to Table 85.
As shown in Table 66 to Table 75, the polyol ester oils each produced by esterifying an alcohol ingredient obtained by mixing pentaerythritol with dipentaerythritol and a fatty acid ingredient composed of at least one of pentanoic acid and hexanoic acid and at least one of octanoic acid and nonanoic acid are made to have various values of viscosity by changing the proportions of the raw materials with respect to each of specific raw material combinations.
Furthermore, as shown in Table 49 to Table 56, refrigeration oil compositions which are excellent in terms of solubility and lubricity can be produced even with hydrocarbon refrigerants having an exceedingly low global warming potential, by using polyol ester oils each produced by esterifying an alcohol ingredient obtained by mixing pentaerythritol with dipentaerythritol and a fatty acid ingredient composed of at least one of pentanoic acid and hexanoic acid and at least one of octanoic acid and nonanoic acid.
Moreover, as shown in Table 61 to Table 65, the polyol ester oils each produced by esterifying an alcohol ingredient obtained by mixing pentaerythritol with dipentaerythritol and a fatty acid ingredient composed of at least one of pentanoic acid and hexanoic acid and at least one of octanoic acid and nonanoic acid have the properties and performances which are required of refrigeration oils, as compared with the mineral oil (comparative oil 15B) for refrigerant R290 and with Comparative Example 1B, etc.
While the invention has been described in detail and with reference to specific embodiments thereof, it will be apparent to one skilled in the art that various changes and modifications can be made therein without departing from the spirit and scope thereof.
This application is based on a Japanese patent application filed on Dec. 27, 2011 (Application No. 2011-286045) and a Japanese patent application filed on Dec. 12, 2012 (Application No. 2012-270435), the contents thereof being incorporated herein by reference.
The present invention is useful as refrigeration oil compositions for hydrofluorocarbon-based refrigerants or hydrocarbon-based refrigerants.
| Number | Date | Country | Kind |
|---|---|---|---|
| 2011-286045 | Dec 2011 | JP | national |
| 2012-270435 | Dec 2012 | JP | national |
| Filing Document | Filing Date | Country | Kind |
|---|---|---|---|
| PCT/JP2012/083982 | 12/27/2012 | WO | 00 |
| Publishing Document | Publishing Date | Country | Kind |
|---|---|---|---|
| WO2013/100100 | 7/4/2013 | WO | A |
| Number | Name | Date | Kind |
|---|---|---|---|
| 5021179 | Zehler et al. | Jun 1991 | A |
| 5494597 | Krevalis, Jr. et al. | Feb 1996 | A |
| 5833876 | Schnur et al. | Nov 1998 | A |
| 5853609 | Schnur | Dec 1998 | A |
| 5906769 | Schnur | May 1999 | A |
| 6228820 | Sakai et al. | May 2001 | B1 |
| 20010019120 | Schnur et al. | Sep 2001 | A1 |
| 20030047707 | Schnur et al. | Mar 2003 | A1 |
| 20050145823 | Yamada et al. | Jul 2005 | A1 |
| 20060255313 | Yamada et al. | Nov 2006 | A1 |
| 20060278845 | Kajiki et al. | Dec 2006 | A1 |
| 20100190672 | Carr et al. | Jul 2010 | A1 |
| 20130207024 | Takigawa et al. | Aug 2013 | A1 |
| Number | Date | Country |
|---|---|---|
| 102191112 | Sep 2011 | CN |
| 41 05 956 | Aug 1992 | DE |
| 5-132684 | May 1993 | JP |
| 7-507346 | Aug 1995 | JP |
| 8-503975 | Apr 1996 | JP |
| 2787083 | Aug 1998 | JP |
| 2000-502391 | Feb 2000 | JP |
| 2002-129178 | May 2002 | JP |
| 2002356694 | Dec 2002 | JP |
| 2003-501614 | Jan 2003 | JP |
| 2003-041278 | Feb 2003 | JP |
| 3510888 | Mar 2004 | JP |
| 2005-171233 | Jun 2005 | JP |
| 3909744 | Apr 2007 | JP |
| 2010-031134 | Feb 2010 | JP |
| 2010-235960 | Oct 2010 | JP |
| 2011-190319 | Sep 2011 | JP |
| 2011-195630 | Oct 2011 | JP |
| 2011-195631 | Oct 2011 | JP |
| 9324587 | Dec 1993 | WO |
| 9325629 | Dec 1993 | WO |
| 9711933 | Apr 1997 | WO |
| 9723585 | Jul 1997 | WO |
| 2012026303 | Mar 2012 | WO |
| 2013027428 | Feb 2013 | WO |
| Entry |
|---|
| PCT Written Opinion, PCT/JP2012/083982, dated Dec. 2011. |
| Office Action issued in corresponding Chinese Patent Application No. 201280065302.6, dated Jul. 22, 2015, 13 pages with an English translation. |
| Extended European Search Report issued in corresponding European Application No. 12 86 2756.9, dated Aug. 4, 2015, 6 pages. |
| Office Action issued in corresponding Japanese Patent Application No. 2011-286045, dated May 24, 2016, 5 pages with translation. |
| Office Action issued in corresponding Chinese Patent Application No. 201280065302.6, dated May 23, 2016, 12 pages with translation. |
| Office Action issued in corresponding Japanese Application Serial No. 2011-286045, dated Dec. 8, 2015, 11 pages with English translation. |
| Office Action issued in corresponding Taiwanese Application No. 10421699070, dated Dec. 16, 2015, 9 pages with translation. |
| Number | Date | Country | |
|---|---|---|---|
| 20140374647 A1 | Dec 2014 | US |
