Refrigerating machine oil composition and refrigerating machine mixture composition

Abstract

To provide a refrigerating machine oil composition and a mixed composition for a refrigerating machine containing the refrigerating machine oil composition, wherein the refrigerating machine oil composition has an appropriate melt viscosity when a hydrocarbon-based refrigerant is dissolved, and has a low solubility of the hydrocarbon-based refrigerant.SOLUTION: A refrigerating machine oil composition used for a refrigerant containing a hydrocarbon refrigerant comprises one or more selected from polyalkylene glycol compounds (A) represented by the following general formula (1). In the general formula (1), one or both of R1 and R2 are groups represented by the following general formula (2). When one of R1 and R2 is a group represented by the following general formula (2), the other is a hydrogen atom or a linear or branched alkyl group having 1 to 16 carbon atoms. E is an ethylene group, P is a propylene group, and m and n are integers of 0 or more, where m+n is 1 or more and 50 or less.SELECTED DRAWING: None

Description

Technical Field

[0001] The present invention relates to a refrigerant oil composition and a mixed composition for a refrigerator. In the present specification, the "mixed composition for a refrigerator" refers to a composition obtained by mixing a "refrigerant oil composition" and a "refrigerant".

Background Art

[0002] For example, a refrigerator such as a compression-type refrigerator generally includes at least a compressor, a condenser, an expansion mechanism (e.g., an expansion valve, etc.), and an evaporator, and has a structure in which a mixed composition for a refrigerator circulates in a sealed system.

[0003] As a refrigerant used in a refrigerator such as a compression-type refrigerator, a hydrocarbon compound with a low environmental impact is being used instead of the conventionally widely used hydrochlorofluorocarbon (HCFC). Examples of the hydrocarbon compound include saturated hydrofluorocarbon compounds (Hydro-Fluoro-Carbon; hereinafter, also referred to as "HFC") such as 1,1,1,2-tetrafluoroethane (R134a), difluoromethane (R32), 1,1-difluoroethane (R152a), and a mixture of difluoromethane and pentafluoroethane (R410A). In addition, the use of unsaturated hydrofluorocarbon compounds (Hydro-Fluoro-Olefin; hereinafter, also referred to as "HFO") such as 1,3,3,3-tetrafluoropropene (R1234ze), 2,3,3,3-tetrafluoropropene (R1234yf), and 1,2,3,3-tetrafluoropropene (R1234ye) with a low global warming potential (GWP) is also being considered.

[0004] In recent years, from the viewpoint of further reducing the global warming potential (GWP), the application of hydrocarbon refrigerants such as propane (R290) is also being considered (for example, refer to Patent Document 1).

Prior Art Documents

Patent Documents

[0005] Patent Document 1 Japanese Patent Application Laid-Open No. 2004-043611 SUMMARY OF THE INVENTION PROBLEMS TO BE SOLVED BY THE INVENTION

[0006] By the way, compared with HFC refrigerants and HFO refrigerants, hydrocarbon refrigerants tend to have a lower viscosity (hereinafter also referred to as "dissolved viscosity") of a refrigerant mixture composition for a refrigerator in which the refrigerant is dissolved in a refrigeration oil composition. A decrease in the dissolved viscosity is a factor in the progress of wear at sliding parts such as a compressor of a refrigerator. Therefore, the refrigeration oil composition used when using a hydrocarbon refrigerant is required to have an appropriate dissolved viscosity so that good lubricity is exhibited even when the hydrocarbon refrigerant is dissolved. In addition, hydrocarbon refrigerants are highly flammable. Therefore, from the viewpoint of ensuring safety easily, it is desirable to reduce the amount of hydrocarbon refrigerant used. Therefore, it is desirable that the refrigeration oil composition used when using a hydrocarbon refrigerant reduces the amount of the hydrocarbon refrigerant dissolved and suppresses excessive dissolution of the hydrocarbon refrigerant. From the viewpoint of achieving such a demand, it is desirable that the refrigeration oil composition used when using a hydrocarbon refrigerant has a low solubility of the hydrocarbon refrigerant. However, the refrigeration oil composition of Patent Document 1 is insufficient in any performance.

[0007] Therefore, an object of the present invention is to provide a refrigeration oil composition having an appropriate dissolved viscosity when a hydrocarbon refrigerant is dissolved and having a low solubility of the hydrocarbon refrigerant, and a refrigerant mixture composition for a refrigerator containing the refrigeration oil composition. MEANS FOR SOLVING THE PROBLEMS

[0008] According to the present invention, the following [1] to [3] are provided. [1] A refrigeration oil composition used for a refrigerant containing a hydrocarbon refrigerant, A refrigeration oil composition containing at least one selected from polyalkylene glycol compounds (A) represented by the following general formula (1). [Chemical formula] [In the general formula (1), one or both of R 1 and R 2 is a group represented by the following general formula (2). When one of R 1 and R 2 is a group represented by the following general formula (2), the other is a hydrogen atom or a linear or branched alkyl group having 1 to 16 carbon atoms. E is an ethylene group, and P is a propylene group. m and n are integers of 0 or more. However, m + n is 1 or more and 50 or less.] [Chemical formula] [In the general formula (2), R 3 is a linear or branched alkyl group having 1 to 22 carbon atoms or a linear or branched alkenyl group having 2 to 22 carbon atoms. In the general formula (1), when both of R 1 and R 2 are groups represented by the general formula (2), the two R 3 may be the same or different. The wavy line indicates the bonding site with the oxygen atom in the general formula (1).] [2] A refrigerant composition for a refrigerator, comprising the refrigerant oil composition according to [1] above and a refrigerant containing a hydrocarbon refrigerant. [3] A method for producing a refrigerant oil composition used for a refrigerant containing a hydrocarbon refrigerant, comprising a step of blending one or more selected from polyalkylene glycol compounds (A) represented by the following general formula (1). A method for producing a refrigerant oil composition. [Chemical formula] [In the general formula (1), one or both of R 1 and R 2 is a group represented by the following general formula (2). R 1 and R 2When one of them is a group represented by the following general formula (2), the other is a hydrogen atom or a linear or branched alkyl group having 1 to 16 carbon atoms. E is an ethylene group, and P is a propylene group. m and n are integers of 0 or more. However, m + n is 1 or more and 50 or less.] [Chemical formula] [In the general formula (2), R 3 is a linear or branched alkyl group having 1 to 22 carbon atoms or a linear or branched alkenyl group having 2 to 22 carbon atoms. In the general formula (1), when both R 1 and R 2 are groups represented by the general formula (2), the two existing R 3 may be the same or different. The wavy line indicates the bonding site with the oxygen atom in the general formula (1).] [Advantages of the Invention]

[0009] According to the present invention, it is possible to provide a refrigerant oil composition having an appropriate dissolution viscosity when a hydrocarbon refrigerant is dissolved and having a low solubility of the hydrocarbon refrigerant, and a refrigerant mixture composition for a refrigerator including the refrigerant oil composition. [Brief Description of the Drawings]

[0010]

Figure 1

Figure 2

Figure 3

[0011] The upper and lower limit values of the numerical ranges described in this specification can be arbitrarily combined. For example, when the numerical ranges "A to B" and "C to D" are described, the numerical ranges "A to D" and "C to B" are also included in the scope of the present invention. In addition, the numerical range "lower limit value to upper limit value" described in this specification means, unless otherwise specified, that it is greater than or equal to the lower limit value and less than or equal to the upper limit value. In addition, in this specification, the numerical values in the examples are numerical values that can be used as the upper limit value or the lower limit value. In the following description, the "polyalkylene glycol-based compound" may also be abbreviated as the "PAG-based compound".

[0012] [Embodiments of Refrigerant Oil Compositions] The refrigerant oil composition of this embodiment is a refrigerant oil composition used for a refrigerant containing a hydrocarbon-based refrigerant, and contains one or more selected from PAG-based compounds (A) represented by the following general formula (1). [Chemical Formula] [In the general formula (1), R 1 and R 2 One or both of them are groups represented by the following general formula (2). When one of R 1 and R 2 is a group represented by the following general formula (2), the other is a hydrogen atom or a linear or branched alkyl group having 1 or more and 16 or less carbon atoms. E is an ethylene group, and P is a propylene group. m and n are integers of 0 or more. However, m + n is 1 or more and 50 or less.] [Chemical Formula] [In the general formula (2), R 3 is a linear or branched alkyl group having 1 or more and 22 or less carbon atoms or a linear or branched alkenyl group having 2 or more and 22 or less carbon atoms. In the general formula (1), when both R 1 and R 2 are groups represented by the general formula (2), two existing R3 They may be the same or different. The wavy line portion indicates the bonding site with the oxygen atom in the general formula (1).

[0013] The inventors of the present invention conducted intensive studies to solve the above problems. As a result, it was found that the PAG-based compound (A) represented by the general formula (1) has an appropriate dissolution viscosity when a hydrocarbon-based refrigerant is dissolved, and the solubility of the hydrocarbon-based refrigerant is low, leading to the completion of the present invention.

[0014] Although the mechanism by which the effects of the present invention are achieved is not clear, it is presumed as follows, for example. That is, it is presumed to be due to the fact that the PAG-based compound (A) represented by the general formula (1) has an ester structure at at least one molecular terminal, and the PAG-based compound (A) represented by the general formula (1) has a molecular structure excellent in balance in achieving the above problems.

[0015] In the refrigerant oil composition of the present embodiment, the PAG-based compound (A) functions as a base oil. Here, the refrigerant oil composition of the present embodiment may be composed only of the PAG-based compound (A), but may contain other components other than the PAG-based compound (A) as long as the effects of the present invention are not impaired. In the refrigerant oil composition of the present embodiment, the content of the PAG-based compound (A) is preferably 80% by mass or more, more preferably 85% by mass or more, still more preferably 90% by mass or more, based on the total amount (100% by mass) of the refrigerant oil composition. Also, it is preferably 100% by mass or less. The upper and lower limit values of these numerical ranges can be arbitrarily combined. Specifically, it is preferably 80% by mass to 100% by mass, more preferably 85% by mass to 100% by mass, still more preferably 90% by mass to 100% by mass.

[0016] Hereinafter, the components contained in the refrigerant oil composition of the present embodiment will be described in detail.

[0017] <PAG-based compound (A)> The refrigerant oil composition of this embodiment contains a PAG-based compound (A). The PAG-based compound (A) is one or more selected from the compounds represented by the following general formula (1).

Chemical formula

[0018] Here, in the above general formula (1), R 1 and R 2 One or both of them are groups represented by the following general formula (2).

Chemical formula

[0019] In the above general formula (2), R 3 is a linear or branched alkyl group having 1 to 22 carbon atoms or a linear or branched alkenyl group having 2 to 22 carbon atoms. When the number of carbon atoms of the alkyl group and the alkenyl group is 23 or more, it is difficult to obtain the raw materials for introducing the group represented by the above general formula (2). In addition, since the PAG-based compound is likely to crystallize, the pour point may increase.

[0020] R 3 The number of carbon atoms of the alkyl group or alkenyl group that can be selected as R is preferably 4 or more, more preferably 8 or more, still more preferably 10 or more, even more preferably 12 or more, still more preferably 14 or more, even more preferably 16 or more, from the viewpoints of making the viscosity of the PAG-based compound (A) itself within an appropriate range and making it difficult for the dissolved viscosity to decrease when the hydrocarbon-based refrigerant is dissolved and facilitating an appropriate dissolved viscosity. Also, the number of carbon atoms of the alkyl group or alkenyl group that can be selected as R 3 is 22 or less as described above, but is preferably 20 or less from the viewpoints of the availability of raw materials for introducing the group represented by the above general formula (2) and ensuring an appropriate pour point. The upper and lower limit values of these numerical ranges can be arbitrarily combined. Specifically, preferably 4 to 22, more preferably 8 to 22, still more preferably 10 to 22, even more preferably 12 to 20, yet even more preferably 14 to 20, still more preferably 16 to 20.

[0021] R 3 The alkyl group or alkenyl group that can be selected as R may be linear or branched, but from the viewpoint of improving the viscosity index and facilitating the improvement of the viscosity characteristics of the PAG-based compound (A) (in other words, from the viewpoint of easily adjusting the viscosity within an appropriate range in a wide temperature region), it is preferably linear.

[0022] R 3 Examples of the linear or branched alkyl group that can be selected as R include a methyl group, an ethyl group, a propyl group, a butyl group, a pentyl group, a hexyl group, a heptyl group, an octyl group, a nonyl group, a decyl group, an undecyl group, a dodecyl group, a tridecyl group, a tetradecyl group, a pentadecyl group, a hexadecyl group, a heptadecyl group, an octadecyl group, a nonadecyl group, an icosyl group, a heneicosyl group, and a docosyl group, etc.

[0023] R 3 Examples of the linear or branched alkenyl group that can be selected as R include an ethenyl group, a propenyl group, a butenyl group, a pentenyl group, a hexenyl group, a heptenyl group, an octenyl group, a nonenyl group, a decenyl group, an undecenyl group, a dodecenyl group, a tridecenyl group, a tetradecenyl group, a pentadecenyl group, a hexadecenyl group, a heptadecenyl group, an octadecenyl group, a nonadecenyl group, an icosenyl group, a heneicosenyl group, and a docosenyl group.

[0024] In addition, the branching position and the number of branches in the branched alkyl group or the branched alkenyl group are not particularly limited. Also, the unsaturated bond site and the unsaturated bond site in the alkenyl group are not particularly limited.

[0025] Here, in the above general formula (1), R 1and R 2 When only one of them is a group represented by the general formula (2), R 1 and R 2 The other is a hydrogen atom or a linear or branched alkyl group having 1 to 16 carbon atoms. When the number of carbon atoms of the alkyl group is 17 or more, it becomes difficult to obtain the PAG-based compound. Examples of the linear or branched alkyl group having 1 to 16 carbon atoms include a methyl group, an ethyl group, a propyl group, a butyl group, a pentyl group, a hexyl group, a heptyl group, an octyl group, a nonyl group, a decyl group, an undecyl group, a dodecyl group, a tridecyl group, a tetradecyl group, a pentadecyl group, and a hexadecyl group. In addition, the branching position and the number of branches in the branched alkyl group are not particularly limited.

[0026] In the general formula (1) above, E is an ethylene group and P is a propylene group. Therefore, in the general formula (1) above, "EO" means an oxyethylene group and "PO" means an oxypropylene group.

[0027] In the general formula (1) above, m and n are integers of 0 or more. However, m + n is 1 or more and 50 or less. Therefore, the PAG-based compound (A) represented by the general formula (1) may contain only an oxyethylene group, may contain only an oxypropylene group, or may contain both an oxyethylene group and an oxypropylene group. When m + n is 51 or more, the viscosity of the PAG-based compound (A) itself becomes too high, and it becomes difficult to adjust the viscosity of the PAG-based compound (A) itself to an appropriate range. Here, from the viewpoint of making the viscosity of the PAG-based compound (A) itself fall within an appropriate range, the value of m + n is preferably 4 to 40, more preferably 5 to 30, and still more preferably 7 to 24.

[0028] Here, in the present embodiment, from the viewpoint of more easily exhibiting the effects of the present invention, in the general formula (1), R 1 and R2 It is preferable that both are groups represented by the above general formula (2). That is, the PAG-based compound (A) is preferably a compound represented by the following general formula (1a).

Chemical formula

[0029] In the above general formula (1a), R 3 , m, and n are as described above in the above general formulas (1) and (2), and the preferable ranges are also as described above in the above general formulas (1) and (2). Incidentally, the two Rs 3 may be the same or different, but from the viewpoint of easy availability of the PAG-based compound (A) etc., it is preferable that they are the same.

[0030] <Production method of PAG-based compound (A)> The production method of the PAG-based compound (A) is not particularly limited, but for example, it can be produced by reacting a compound represented by the following general formulas (1-1) to (1-3) with a compound represented by the following general formula (2-1) for esterification.

Chemical formula

Chemical formula

Chemical formula

Chemical formula

[0031] <Kinematic viscosity of PAG-based compound (A)> The kinematic viscosity of PAG-based compound (A) at 40 °C is preferably 20 mm 2 / s or more, more preferably 30 mm 2 / s or more, still more preferably 40 mm 2 / s or more. Also, from the viewpoint of oil return, it is preferably 350 mm 2 / s or less, more preferably 320 mm 2 / s or less, still more preferably 300 mm 2 / s or less. The upper and lower limit values of these numerical ranges can be arbitrarily combined. Specifically, it is preferably 20 mm 2 / s to 350 mm 2 / s, more preferably 30 mm 2 / s to 320 mm 2 / s, still more preferably 40 mm 2 / s to 300 mm 2 / s.

[0032] The kinematic viscosity of PAG-based compound (A) at 100 °C is preferably 4 mm 2 / s or more, more preferably 6 mm 2 / s or more, still more preferably 8 mm 2 / s or more, even more preferably 9 mm 2 / s or more. Also, from the viewpoint of oil return, it is preferably 70 mm 2 / s or less, more preferably 60 mm 2 / s or less, still more preferably 50 mm 2 / s or less. The upper and lower limit values of these numerical ranges can be arbitrarily combined. Specifically, it is preferably 4 mm 2 / s to 70 mm 2 / s, more preferably 6 mm 2 / s to 70 mm 2 / s, more preferably 8 mm 2 / s to 60 mm 2 / s, even more preferably 9 mm 2 / s to 50 mm 2 / s.

[0033] In the present specification, the kinematic viscosity of the PAG-based compound (A) means a value measured in accordance with JIS K2283:2000.

[0034] <Viscosity index of PAG-based compound (A)> From the viewpoint of facilitating the improvement of the viscosity characteristics of the PAG-based compound (A) (in other words, from the viewpoint of easily adjusting the viscosity within an appropriate range in a wide temperature range), the viscosity index of the PAG-based compound (A) is preferably 150 or more, more preferably 170 or more, even more preferably 190 or more, and even more preferably 200 or more. The upper limit value of the viscosity index of the PAG-based compound (A) is not particularly limited, but is usually 300 or less.

[0035] <Other base oils other than PAG-based compound (A)> The refrigerant oil composition of the present embodiment may or may not further contain other base oils other than the PAG-based compound (A). Examples of other base oils other than the PAG-based compound (A) include one or more selected from the group consisting of mineral oils and synthetic oils not applicable to the PAG-based compound (A).

[0036] Examples of mineral oils include atmospheric residue obtained by atmospheric distillation of crude oils such as paraffinic crude oil, intermediate-base crude oil, and naphthenic crude oil; distillate oil obtained by vacuum distillation of these atmospheric residues; mineral oil obtained by subjecting the distillate oil to one or more treatments such as solvent dewaxing, solvent extraction, hydrocracking, solvent deasphalting, catalytic deasphalting, and hydrorefining; and wax isomerized mineral oil. Note that the mineral oil may be used alone or in combination of two or more.

[0037] Synthetic oils that do not correspond to the PAG-based compound (A) include polyvinyl ethers; polyalkylene glycols that do not correspond to the PAG-based compound (A); copolymers of polyalkylene glycol or its monoether and polyvinyl ether; polyol esters; polyesters; polycarbonates; hydrogenated products of α-olefin oligomers; alicyclic hydrocarbon compounds; alkylated aromatic hydrocarbon compounds; GTL base oils produced by isomerizing GTL WAX (gas to liquid wax) produced by the Fischer-Tropsch process, etc. Note that the synthetic oil may be used alone or in combination of two or more.

[0038] From the viewpoint of making it easier to exhibit the effects of the present invention, the content of mineral oil is preferably low. Specifically, the content of mineral oil is preferably less than 10 parts by mass, more preferably less than 1 part by mass, still more preferably less than 0.1% by mass, even more preferably not containing mineral oil, based on 100 parts by mass of the PAG-based compound (A). Also, from the same viewpoint, the content of the synthetic oil that does not correspond to the PAG-based compound (A) is preferably low. Specifically, the content of the synthetic oil that does not correspond to the PAG-based compound (A) is preferably less than 100 parts by mass, more preferably less than 50 parts by mass, still more preferably less than 30 parts by mass, even more preferably less than 10 parts by mass, still more preferably less than 1 part by mass, even more preferably less than 0.1 part by mass, and even more preferably not containing the synthetic oil that does not correspond to the PAG-based compound (A), based on 100 parts by mass of the PAG-based compound (A).

[0039] <Additive> The refrigerant oil composition of the present embodiment may further contain an additive or may not contain an additive as long as the effects of the present invention are not impaired. Examples of the additive include additives that can generally be blended in the refrigerant oil composition. Examples of such additives include one or more selected from the group consisting of antioxidants, oxygen scavengers, acid scavengers, extreme pressure agents, oiliness agents, metal deactivators, and defoamers. The total content of these additives is preferably 0% by mass to 10% by mass, more preferably 0.01% by mass to 5% by mass, and still more preferably 0.1% by mass to 3% by mass, based on the total amount (100% by mass) of the refrigeration machine oil composition.

[0040] (Antioxidant) 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-based antioxidants such as phenyl-α-naphthylamine and N,N'-diphenyl-p-phenylenediamine. The antioxidant may be used alone or in combination of two or more.

[0041] (Oxygen scavenger) Examples of the oxygen scavenger include aliphatic unsaturated compounds and terpenes having a double bond. As the aliphatic unsaturated compound, an unsaturated hydrocarbon is preferable, and specifically, olefins; polyenes such as dienes and trienes are exemplified. As the olefin, from the viewpoint of reactivity with oxygen, α-olefins such as 1-tetradecene, 1-hexadecene, and 1-octadecene are preferable. As the aliphatic unsaturated compound other than the above, from the viewpoint of reactivity with oxygen, unsaturated aliphatic alcohols having a conjugated double bond such as vitamin A ((2E,4E,6E,8E)-3,7-dimethyl-9-(2,6,6-trimethylcyclohex-1-yl)nona-2,4,6,8-tetraen-1-ol) represented by the molecular formula C 20 H 30 O are preferable. As the terpenes having a double bond, terpene hydrocarbons having a double bond are preferable, and from the viewpoint of reactivity with oxygen, α-farnesene (C 15 H 24 : 3,7,11-trimethyldodeca-1,3,6,10-tetraene) and β-farnesene (C 15 H 24: 7,11 - dimethyl - 3 - methylidene dodeca - 1,6,10 - triene) is more preferable. The oxygen scavenger may be used alone or in combination of two or more.

[0042] (Acid scavenger) Examples of the acid scavenger include epoxy compounds such as phenyl glycidyl ether, alkyl glycidyl ether, alkylene glycol glycidyl ether, cyclohexene oxide, α - olefin oxide, and epoxidized soybean oil. As the acid scavenger, at least one selected from glycidyl esters, glycidyl ethers, and α - olefin oxides is preferably used. Examples of the glycidyl ether include those derived from linear, branched, or cyclic saturated or unsaturated aliphatic mono - or polyhydric alcohols having 3 to 30 carbon atoms, preferably 4 to 24 carbon atoms, more preferably 6 to 16 carbon atoms, or aromatic compounds containing one or more hydroxyl groups. In the case of aliphatic polyhydric alcohols or aromatic compounds containing two or more hydroxyl groups, from the viewpoint of suppressing the increase in hydroxyl value for the stability of the lubricating oil composition, it is preferable that all of the hydroxyl groups are glycidyl - etherified. Among these, glycidyl ethers derived from linear, branched, or cyclic saturated aliphatic monohydric alcohols having 6 to 16 carbon atoms are particularly preferable. Examples of such glycidyl ethers include 2 - ethyl ethyl glycidyl ether, isononyl glycidyl ether, caprinoyl glycidyl ether, lauryl glycidyl ether, myristyl glycidyl ether, etc. On the other hand, as the α - olefin oxide, those having 4 to 50 carbon atoms, preferably 4 to 24 carbon atoms, more preferably 6 to 16 carbon atoms are used. The acid scavenger may be used alone or in combination of two or more.

[0043] (Extreme pressure agent) Examples of the extreme pressure agent include phosphorus - based extreme pressure agents such as phosphate esters, acidic phosphate esters, phosphite esters, acidic phosphite esters, and amine salts thereof. Among these phosphorus-based extreme pressure agents, tricresyl phosphate, triphenyl thiophosphate, tri(nonylphenyl) phosphite, dioleyl hydrogen phosphite, 2-ethylhexyl diphenyl phosphite, etc. are particularly preferable in terms of extreme pressure properties, friction characteristics, etc. In addition, examples of the extreme pressure agent include metal salts of carboxylic acids. The metal salts of carboxylic acids referred to here are preferably metal salts of carboxylic acids having 3 to 60 carbon atoms, more preferably metal salts of fatty acids having 3 to 30 carbon atoms, particularly preferably 12 to 30 carbon atoms. Further, metal salts of dimer acids and trimer acids of the above fatty acids and dicarboxylic acids having 3 to 30 carbon atoms can be mentioned. Among these, metal salts of fatty acids having 12 to 30 carbon atoms and dicarboxylic acids having 3 to 30 carbon atoms are particularly preferable. On the other hand, as the metal constituting the metal salt, an alkali metal or an alkaline earth metal is preferable, and particularly, an alkali metal is optimal. In addition, as the extreme pressure agent, further, as extreme pressure agents other than the above, for example, sulfur-based extreme pressure agents such as sulfurized oils and fats, sulfurized fatty acids, sulfurized esters, sulfurized olefins, dihydrocarbyl polysulfides, thiocarbamates, thioterpenes, dialkyl thiodipropionates, etc. can be mentioned. The extreme pressure agent may be used alone or in combination of two or more.

[0044] (Lubricating oil additive) Examples of the lubricating oil additive include aliphatic saturated and unsaturated monocarboxylic acids such as stearic acid and oleic acid, polymerized fatty acids such as dimer acid and hydrogenated dimer acid, hydroxy fatty acids such as ricinoleic acid and 12-hydroxystearic acid, aliphatic saturated and unsaturated monoalcohols such as lauryl alcohol and oleyl alcohol, aliphatic saturated and unsaturated monoamines such as stearylamine and oleylamine, aliphatic saturated and unsaturated monocarboxylic acid amides such as lauric acid amide and oleic acid amide, and partial esters of polyhydric alcohols such as glycerin and sorbitol and aliphatic saturated or unsaturated monocarboxylic acids. The lubricating oil additive may be used alone or in combination of two or more.

[0045] (Metal deactivator) Examples of the metal deactivator include copper deactivators such as N-[N,N'-dialkyl (alkyl group having 3 to 12 carbon atoms) aminomethyl] triazole and the like. The metal deactivator may be used alone or in combination of two or more.

[0046] (Defoaming agent) Examples of the defoaming agent include silicone oil, fluorinated silicone oil and the like. The defoaming agent may be used alone or in combination of two or more.

[0047] [Method for producing a refrigeration oil composition] The method for producing the refrigeration oil composition of this embodiment is not particularly limited. For example, the method for producing the refrigeration oil composition of this embodiment is a method for producing a refrigeration oil composition used for a refrigerant containing a hydrocarbon refrigerant, and has a step of blending one or more selected from polyalkylene glycol compounds (A) represented by the following general formula (1). [Chemical formula] [In the general formula (1), R 1 and R 2 One or both of them are groups represented by the following general formula (2). When one of R 1 and R 2 is a group represented by the following general formula (2), the other is a hydrogen atom or a linear or branched alkyl group having 1 or more and 16 or less carbon atoms. E is an ethylene group, and P is a propylene group. m and n are integers of 0 or more. However, m + n is 1 or more and 50 or less.] [Chemical formula] [In the general formula (2), R 3is a linear or branched alkyl group having 1 to 22 carbon atoms or a linear or branched alkenyl group having 2 to 22 carbon atoms. In the general formula (1), R 1 and R 2 When both are groups represented by the general formula (2), the two R 3 may be the same or different. The wavy line indicates the bonding site with the oxygen atom in the general formula (1).]

[0048] As the step of blending one or more selected from the PAG-based compound (A) represented by the general formula (1), for example, one or more selected from the PAG-based compound (A) obtained by the above-described production method of the PAG-based compound (A) can be blended.

[0049] The method for producing the refrigerant oil composition of the present embodiment may or may not further include a step of mixing the PAG-based compound (A) with another base oil other than the PAG-based compound (A), and further a step of mixing the above additive. When the above additive is blended with the PAG-based compound (A), the additive may be blended after adding a diluent oil or the like to form a solution (dispersion). In the general formula (1), the preferred ranges of R 1 , R 2 , m, and n are as described above in the description of the PAG-based compound (A). In the general formula (2), the preferred range of R 3 is also as described above in the description of the PAG-based compound (A).

[0050] [Physical properties of refrigerant oil composition] <Kinematic viscosity of refrigerant oil composition> The kinematic viscosity of the refrigerant oil composition at 40 ° C is preferably 20 mm 2 / s or more, more preferably 30 mm 2 / s or more, still more preferably 40 mm 2 / s or more. Also, from the viewpoint of oil return, it is preferably 350 mm 2 / s or less, more preferably 320 mm 2 / s or less, more preferably 300 mm 2 / s or less. The upper and lower limit values of these numerical ranges can be arbitrarily combined. Specifically, preferably 20 mm 2 / s to 350 mm 2 / s, more preferably 30 mm 2 / s to 320 mm 2 / s, still more preferably 40 mm 2 / s to 300 mm 2 / s.

[0051] From the viewpoint of suppressing wear in sliding parts such as the compressor of the refrigerator, the kinematic viscosity of the refrigerator oil composition at 100 °C is preferably 4 mm 2 / s or more, more preferably 6 mm 2 / s or more, still more preferably 8 mm 2 / s or more, even more preferably 9 mm 2 / s or more. Also, from the viewpoint of oil return, preferably 70 mm 2 / s or less, more preferably 60 mm 2 / s or less, still more preferably 50 mm 2 / s or less. The upper and lower limit values of these numerical ranges can be arbitrarily combined. Specifically, preferably 4 mm 2 / s to 70 mm 2 / s, more preferably 6 mm 2 / s to 70 mm 2 / s, still more preferably 8 mm 2 / s to 60 mm 2 / s, even more preferably 9 mm 2 / s to 50 mm 2 / s.

[0052] In this specification, the kinematic viscosity of the refrigerator oil composition means a value measured in accordance with JIS K2283:2000.

[0053] <Dissolution Viscosity of Refrigerator Oil Composition When Hydrocarbon Refrigerant is Dissolved> The dissolved viscosity of the refrigerant oil composition when the hydrocarbon refrigerant is dissolved, measured by the method described in the examples below, is preferably 2.2 mm 2 / s or more, more preferably 2.5 mm 2 / s or more, still more preferably 3.0 mm 2 / s or more, even more preferably 3.5 mm 2 / s or more, still even more preferably 3.7 mm 2 / s or more. Also, it is preferably 50 mm 2 / s or less. Note that the dissolved viscosity is a value measured in a state where the hydrocarbon refrigerant in the refrigerant oil composition is dissolved. Therefore, the dissolved viscosity can also be said to be the viscosity of the refrigerant mixture composition measured by the method described in the examples below.

[0054] <Solubility of Hydrocarbon Refrigerant in Refrigerant Oil Composition> The solubility of the hydrocarbon refrigerant in the refrigerant oil composition, measured by the method described in the examples below, is preferably less than 18.0% by mass, more preferably 17.5% by mass or less, still more preferably 17.0% by mass or less, from the viewpoint of suppressing the usage amount of the hydrocarbon refrigerant and ensuring safety. Also, it is preferably 1% by mass or more.

[0055] [Refrigerant Mixture Composition for Refrigerator] The above refrigerant oil composition is mixed with a refrigerant and used as a refrigerant mixture composition for a refrigerator. That is, the refrigerant mixture composition for a refrigerator contains the above refrigerant oil composition and a refrigerant. Hereinafter, the refrigerant will be described.

[0056] <Refrigerant> (Hydrocarbon Refrigerant) The refrigerant used in this embodiment is a refrigerant containing a hydrocarbon refrigerant. As the hydrocarbon refrigerant, hydrocarbons having 1 to 8 carbon atoms are preferable, hydrocarbons having 1 to 5 carbon atoms are more preferable, and hydrocarbons having 3 to 5 carbon atoms are still more preferable. When the number of carbon atoms is 8 or less, the boiling point of the refrigerant does not become too high, which is preferable as a refrigerant. Examples of the hydrocarbon refrigerant include one or more selected from the group consisting of methane, ethane, ethylene, propane (R290), cyclopropane, propylene, n-butane, isobutane (R600a), 2-methylbutane, n-pentane, isopentane, cyclopentane isobutane, and normal hexane. The hydrocarbon refrigerant may be used alone or in combination of two or more.

[0057] (Other refrigerants) In the present embodiment, the refrigerant may be a mixed refrigerant containing other refrigerants as necessary in addition to the hydrocarbon refrigerant. Examples of other refrigerants include one or more selected from saturated fluorinated hydrocarbon refrigerants, unsaturated fluorinated hydrocarbon refrigerants, carbon dioxide, and ammonia. Hereinafter, saturated fluorinated hydrocarbon refrigerants and unsaturated fluorinated hydrocarbon refrigerants will be described.

[0058] -Saturated fluorinated hydrocarbon refrigerant- As the saturated fluorinated hydrocarbon refrigerant, fluorides of alkanes having 1 to 4 carbon atoms are preferable, fluorides of alkanes having 1 to 3 carbon atoms are more preferable, and fluorides of alkanes having 1 or 2 carbon atoms (methane or ethane) are still more preferable. Examples of the fluorides of methane or ethane include trifluoromethane (R23), difluoromethane (R32), 1,1-difluoroethane (R152a), 1,1,1-trifluoroethane (R143a), 1,1,2-trifluoroethane (R143), 1,1,1,2-tetrafluoroethane (R134a), 1,1,2,2-tetrafluoroethane (R134), 1,1,1,2,2-pentafluoroethane (R125), and the like. These may be used alone or in combination of two or more.

[0059] -Unsaturated Hydrofluorocarbon Refrigerant- Examples of the unsaturated hydrofluorocarbon refrigerant include compounds represented by the following general formula (3). C x F y H z ···(3) [In the general formula (3), x is an integer from 2 to 6, y is an integer from 1 to 11, z is an integer from 1 to 11, and the molecule has one or more carbon-carbon unsaturated bonds.]

[0060] The general formula (3) represents the types and numbers of elements in the molecule. Specifically, it represents unsaturated hydrofluorocarbon compounds with 2 to 6 carbon atoms. Unsaturated hydrofluorocarbon compounds with 2 to 6 carbon atoms have physical and chemical properties such as boiling point, freezing point, and latent heat of vaporization required for refrigerants. In the general formula (3), the bonding forms of the x carbon atoms represented by C x include carbon-carbon single bonds and unsaturated bonds such as carbon-carbon double bonds. From the perspective of stability, the carbon-carbon unsaturated bond is preferably a carbon-carbon double bond. The unsaturated hydrofluorocarbon compound has one or more unsaturated bonds such as carbon-carbon double bonds in the molecule, and the number is preferably 1. That is, it is more preferable that at least one of the bonding forms of the x carbon atoms represented by C x is a carbon-carbon double bond.

[0061] Preferred examples of the above unsaturated hydrofluorocarbon compounds include fluorides of linear or branched chain olefins with 2 to 6 carbon atoms and cyclic olefins with 4 to 6 carbon atoms. Specifically, fluorides of ethylene with 1 to 3 fluorine atoms introduced, fluorides of propene with 1 to 5 fluorine atoms introduced, fluorides of butene with 1 to 7 fluorine atoms introduced, fluorides of pentene with 1 to 9 fluorine atoms introduced, fluorides of hexene with 1 to 11 fluorine atoms introduced, fluorides of cyclobutene with 1 to 5 fluorine atoms introduced, fluorides of cyclopentene with 1 to 7 fluorine atoms introduced, fluorides of cyclohexene with 1 to 9 fluorine atoms introduced, etc. can be mentioned. Among these, fluorides of propene are preferred, and propene with 3 to 5 fluorine atoms introduced is more preferred. Specifically, one or more selected from 1,3,3,3-tetrafluoropropene (R1234ze), 2,3,3,3-tetrafluoropropene (R1234yf), and 1,2,3,3-tetrafluoropropene (R1234ye) are preferred, and 2,3,3,3-tetrafluoropropene (R1234yf) is more preferred. The unsaturated fluorinated hydrocarbon refrigerant may be used alone or in combination of two or more.

[0062] (Content of hydrocarbon refrigerant in refrigerant) In the present embodiment, the refrigerant contains a hydrocarbon refrigerant. The content of the hydrocarbon refrigerant is preferably 20% by mass to 100% by mass, more preferably 30% by mass to 100% by mass, still more preferably 40% by mass to 100% by mass, even more preferably 50% by mass to 100% by mass, still more preferably 60% by mass to 100% by mass, even more preferably 70% by mass to 100% by mass, still even more preferably 80% by mass to 100% by mass, and even still more preferably 90% by mass to 100% by mass, based on the total amount of the refrigerant.

[0063] (Usage amounts of refrigerant and refrigerant oil composition) In the refrigerant mixture composition for a refrigerator of the present embodiment, the usage amounts of the refrigerant and the refrigerant oil composition are preferably 30 / 70 to 90 / 10 in terms of the mass ratio [(refrigerant oil composition) / (refrigerant)] of the refrigerant oil composition to the refrigerant. When the mass ratio of the refrigerant oil composition to the refrigerant is within this range, lubricity and suitable refrigerating capacity in the refrigerator can be obtained.

[0064] [Uses of refrigerant oil composition and refrigerant mixture composition for refrigerator] The refrigerant oil composition and the refrigerant mixture composition of the present embodiment are preferably used, for example, in a refrigeration system, a hot water supply system, or a heating system. Specifically, air conditioners, refrigerators, freezers, vending machines, and showcases can be mentioned. Examples of air conditioners include car air conditioners such as open-type car air conditioners and electric car air conditioners; gas heat pump (GHP) air conditioners; and the like.

[0065] [One aspect of the present invention provided] In one aspect of the present invention, the following [1] to [7] are provided. [1] A refrigerant oil composition used for a refrigerant containing a hydrocarbon-based refrigerant, The refrigerant oil composition contains one or more selected from polyalkylene glycol-based compounds (A) represented by the following general formula (1). [Chemical formula] [In the general formula (1), R 1 and R 2 One or both of them are groups represented by the following general formula (2). When one of R 1 and R 2 is a group represented by the following general formula (2), the other is a hydrogen atom or a linear or branched alkyl group having 1 or more and 16 or less carbon atoms. E is an ethylene group, and P is a propylene group. m and n are integers of 0 or more. However, m + n is 1 or more and 50 or less.] [Chemical formula] [In the general formula (2), R 3 is a linear or branched alkyl group having 1 or more and 22 or less carbon atoms or a linear or branched alkenyl group having 2 or more and 22 or less carbon atoms. In the general formula (1), when both R 1 and R 2 are groups represented by the general formula (2), the two R 3 present may be the same or different. The wavy line portion indicates the bonding site with the oxygen atom in the general formula (1).] [2] In the general formula (1), R 1 and R 2 both represent a group represented by the general formula (2), and the refrigerant oil composition according to [1] above. [3] In the general formula (1), R 1 and R 2 both represent a group represented by the general formula (2), and in the general formula (2), R 3 is a linear or branched alkyl group having 10 to 22 carbon atoms or a linear or branched alkenyl group having 10 to 22 carbon atoms, and the refrigerant oil composition according to [1] or [2] above. [4] The content of the polyalkylene glycol compound (A) is 80% by mass or more based on the total amount of the refrigerant oil composition, and the refrigerant oil composition according to any one of [1] to [3] above. [5] The hydrocarbon refrigerant is a hydrocarbon having 1 to 8 carbon atoms, and the refrigerant oil composition according to any one of [1] to [4] above. [6] A refrigerant mixture composition for a refrigerator, comprising the refrigerant oil composition according to any one of [1] to [5] above and a refrigerant containing a hydrocarbon refrigerant. [7] A method for producing a refrigerant oil composition used for a refrigerant containing a hydrocarbon refrigerant, comprising a step of blending one or more selected from polyalkylene glycol compounds (A) represented by the following general formula (1). [Chemical formula] [In the general formula (1), one or both of R 1 and R 2 represent a group represented by the following general formula (2). When one of R 1 and R 2 represents a group represented by the general formula (2), the other is a hydrogen atom or a linear or branched alkyl group having 1 to 16 carbon atoms. E is an ethylene group, and P is a propylene group. m and n are integers of 0 or more. However, m + n is 1 or more and 50 or less.] [Chemical formula] [In the general formula (2), R 3 is a linear or branched alkyl group having 1 to 22 carbon atoms or a linear or branched alkenyl group having 2 to 22 carbon atoms. In the general formula (1), R 1 and R 2 When both are groups represented by the general formula (2), the two R 3 may be the same or different. The wavy line indicates the bonding site with the oxygen atom in the general formula (1).] [Examples]

[0066] The present invention will be specifically described by the following examples. However, the present invention is not limited to the following examples.

[0067] [Measurement methods for various physical property values] The measurement of each raw material used in each example and each comparative example and each property of the refrigerant oil composition of each example and each comparative example was carried out according to the following procedures. (1) Kinematic viscosity The 40 °C kinematic viscosity, 80 °C kinematic viscosity, and 100 °C kinematic viscosity of the PAG-based compound were measured in accordance with JIS K2283:2000. (2) Viscosity index The viscosity index of the PAG-based compound was calculated based on the measurement results of the kinematic viscosity in accordance with JIS K2283:2000.

[0068] [Production Examples 1 to 5, Comparative Production Example 1] Various PAG-based compounds were synthesized according to the following Production Examples 1 to 5 and the following Comparative Production Example 1.

[0069] [Production Example 1: Synthesis of PAG-based compound (A)-1] In a flask equipped with a Dean-Stark trap, 72.5 g (0.1 mol) of Poly(propylene glycol) (manufactured by Sigma-Aldrich, number average molecular weight 725), 34.8 g (0.22 mol) of 3,5,5-trimethylhexanoic acid, 30 g of toluene, and 1.0 g of p-toluenesulfonic acid were added, and the reaction was carried out at 120 °C to 150 °C. The reaction was terminated when a predetermined amount of water was generated, and after alkaline washing with a 3% NaOH aqueous solution, it was washed with distilled water until it became neutral. The toluene in the obtained oil layer was distilled off to obtain the PAG-based compound (A)-1. In the PAG-based compound (A)-1 obtained in Production Example 1, in the above general formula (1), R 1 and R 2 are both groups represented by the above general formula (2). The two R 3 are both iso Octyl groups represented by the following structural formula (4). Also, m = 0 and n = 12.

Chemical formula

[0070] <Production Example 2: Synthesis of PAG-based compound (A)-2> In Production Example 1, instead of 72.5 g (0.1 mol) of Poly(propylene glycol) (manufactured by Sigma-Aldrich, number average molecular weight 725), 40.0 g (0.1 mol) of Poly(ethylene glycol) (manufactured by Sigma-Aldrich, number average molecular weight 400) was added, and under the same conditions otherwise, the PAG-based compound (A)-2 was obtained. In the PAG-based compound (A)-2 obtained in Production Example 2, in the above general formula (1), R 1 and R 2 are both groups represented by the above general formula (2). The two R 3 are both iso Octyl groups represented by the above structural formula (4). Also, m = 9 and n = 0.

[0071] <Production Example 3: Synthesis of PAG-based Compound (A)-3> In Production Example 1, 62.1 g (0.22 mol) of oleic acid was added instead of 34.8 g (0.22 mol) of 3,5,5-trimethylhexanoic acid, and PAG-based Compound (A)-3 was obtained under the same conditions otherwise. In the PAG-based Compound (A)-3 obtained in Production Example 3, in the above general formula (1), R 1 and R 2 are both groups represented by the above general formula (2). The two Rs 3 are both 8-Heptadecenyl groups. Also, m = 0 and n = 12.

[0072] <Production Example 4: Synthesis of PAG-based Compound (A)-4> In Production Example 3, 100 g (0.1 mol) of Poly(propylene glycol) (manufactured by Sigma-Aldrich, number average molecular weight 1,000) was added instead of 72.5 g (0.1 mol) of Poly(propylene glycol) (manufactured by Sigma-Aldrich, number average molecular weight 725), and PAG-based Compound (A)-4 was obtained under the same conditions otherwise. In the PAG-based Compound (A)-4 obtained in Production Example 4, in the above general formula (1), R 1 and R 2 are both groups represented by the above general formula (2). The two Rs 3 are both 8-Heptadecenyl groups. Also, m = 0 and n = 17.

[0073] <Production Example 5: Synthesis of PAG-based Compound (A)-5> In Production Example 4, 100 g (0.1 mol) of Me-O-(PO)n-H (manufactured by Dai-ichi Kogyo Seiyaku Co., Ltd., average molecular weight 1,000) was added instead of 100 g (0.1 mol) of Poly(propylene glycol) (manufactured by Sigma-Aldrich, number average molecular weight 1,000), and PAG-based Compound (A)-5 was obtained under the same conditions otherwise. In the PAG-based Compound (A)-5 obtained in Production Example 5, in the above general formula (1), R 1 and R 2One of them is a group represented by the general formula (2), and the other is a methyl group. R 3 is 8-Heptadecenyl a group. Also, m = 0 and n = 17.

[0074] <Comparative Production Example 1: Synthesis of PAG-based Compound (A')-1> To a 200 milliliter stainless steel autoclave equipped with a stirrer and a liquid introduction tube, 3.0 g (0.056 mol) of powdered sodium methoxide was added, and the autoclave was sealed and heated to 105°C. While stirring, 77 g (1.32 mol) of propylene oxide was pressure-fed into the autoclave through the liquid introduction tube over 9 hours. After adding 100 milliliters of water and 200 milliliters of methanol to the reaction mixture and dissolving it, the solution was passed through a column of 200 milliliters of cation exchange resin and then through a column of 200 milliliters of anion exchange resin to remove sodium ions. After distilling off methanol and water, it was dried at 100°C for 1 hour under reduced pressure with a vacuum pump (0.4 mmHg) to obtain 70 g of polyoxypropylene glycol monomethyl ether. Next, to a 300 milliliter three-necked glass flask equipped with a stirrer and a distillation head, 50 g of the polyoxypropylene glycol monomethyl ether obtained by the above procedure and 80 milliliters of toluene were added. While heating and stirring, about 20 milliliters of toluene was distilled off to remove moisture. After cooling, 25 g (0.13 mol) of a 28 wt% sodium methoxide methanol solution was added, and methanol and about 20 milliliters of toluene were distilled off by heating. After cooling, the content was transferred to a 300 - milliliter stainless - steel autoclave equipped with a stirrer, 36.8 g (0.26 mol) of methyl iodide was added, and after sealing, the temperature was raised from 50 °C to 70 °C over 4.5 hours with stirring and reacted at 85 °C for 12 hours. After cooling to room temperature, the reaction mixture was dissolved in a mixture of 100 milliliters of water and 200 milliliters of methanol, and passed through a column of 200 milliliters of cation - exchange resin and then 200 milliliters of anion - exchange resin. After distilling off the solvent, it was dried at 100 °C for 1 hour under reduced pressure with a vacuum pump (0.1 mmHg) to obtain 42.5 g of PAG - based compound (A’)-1 (dimethyl ether of polyoxypropylene glycol). The PAG - based compound (A’)-1 obtained in Production Example 5 is a compound represented by the following structural formula (5). [Chemical formula] In the above structural formula (5), p = 12.

[0075] [Examples 1 - 5, Comparative Examples 1 - 3] In Examples 1 - 5 and Comparative Examples 1 - 3, the following compounds etc. were used as the refrigerant oil composition and subjected to the evaluation described below. · Example 1: PAG - based compound (A)-1 obtained in Production Example 1 · Example 2: PAG - based compound (A)-2 obtained in Production Example 2 · Example 3: PAG - based compound (A)-3 obtained in Production Example 3 · Example 4: PAG - based compound (A)-4 obtained in Production Example 4 · Example 5: PAG - based compound (A)-5 obtained in Production Example 5 · Comparative Example 1: PAG - based compound (A’)-1 obtained in Comparative Production Example 1 · Comparative Example 2: Mineral oil · Comparative Example 3: Poly - α - olefin (PAO)

[0076] [Evaluation: Evaluation of Dissolution Viscosity and Solubility] (Evaluation of Solubility) A pressure-resistant container made of sapphire glass was filled with a refrigeration oil composition and a predetermined amount of R290 as a refrigerant, and the temperature of the pressure-resistant container was raised from room temperature (23 °C) to 80 °C. A temperature / pressure / solubility curve was created by calculation from the volume of the refrigeration oil composition in which R290 was dissolved and the pressure at that time. From the created solubility curve, the solubility (mass %) of R290 in the refrigeration oil composition at 80 °C and 2.0 MPa was calculated.

[0077] (Evaluation of dissolved viscosity) Using the viscosity measuring device 1 shown in FIGS. 1 to 3, the dissolved viscosity of the refrigeration oil composition in which the refrigerant was dissolved was measured. First, a predetermined amount of the refrigeration oil composition 2 and the capillary viscometer 20 were placed in a container 10 made of a sapphire glass tube, and then the lid 11 was closed. Next, after a safety valve 26 and a needle valve 25 were attached to the T-shaped joint 24, the container 10 was immersed in a constant temperature bath 3 containing a heat medium 4. The temperature of the heat medium 4 was maintained at 80 °C by the temperature adjusting means 5. Next, the needle valve 25 and a refrigerant sampling line (not shown) were connected via a pressure-resistant hose 27, and a vacuum pump (not shown) was operated to degas the inside of the container 10 and the refrigerant sampling line to about 13.3 Pa. After degassing, the vacuum pump was stopped, and the original valve of the refrigerant container was opened to introduce the refrigerant (R290) into the container 10. The refrigerant was introduced so that the pressure in the container 10 became 2.0 MPa. After introducing the refrigerant, the needle valve 25 was closed, the valve of the refrigerant container was closed, and after disconnecting the pressure-resistant hose 27, the sealed container 10 was installed at a predetermined position in the thermostat 3 where the permanent magnet 14 had been lowered to position A. When the entire container 10 reached a thermally equilibrium state, the driving means for moving the permanent magnet 14 was activated to move the permanent magnet 14 and raise the capillary viscometer 20 to position B. As a result, as shown in FIG. 3, the refrigerant-dissolved refrigerating machine oil composition 2 dripped from the capillary viscometer 20, and the liquid level of the refrigerant-dissolved refrigerating machine oil composition 2 dropped. Then, the optical fiber 15 (15A, 15B, 15C, 15D) was made to detect that the liquid level of the refrigerant-dissolved refrigerating machine oil composition 2 had passed the scale line 21B and the scale line 21A, and the viscosimeter automatically measured the time required for the refrigerant-dissolved refrigerating machine oil composition 2 to pass through the inside of the capillary part 22 and automatically measured the viscosity, thereby measuring the dissolution viscosity. The measurement of the dissolution viscosity was carried out after confirming that the refrigerant and the refrigerating machine oil composition were not separated. In FIGS. 1 to 3, reference numeral 6 indicates the gas filled in the container 10. Reference numeral 14A is an arm that holds the permanent magnet 14. Reference numeral 21 is a liquid reservoir part. Reference numeral 23 is a strip-shaped outer ring part made of a magnetic material that is fixed to the outer peripheral surface of the side wall of the capillary part 22.

[0078] The evaluation criteria for the dissolution viscosity were as follows, and evaluations A and B were considered to be passing. · Evaluation A: More than 3.5 mm 2 / s · Evaluation B: 2.2 mm or more and 3.5 mm or less 2 / s 2 / s · Evaluation C: Less than 2.2 mm 2 / s The higher the dissolution viscosity, the better the lubricity when the hydrocarbon-based refrigerant is dissolved, and it can be said that it has an appropriate dissolution viscosity.

[0079] The evaluation criteria for the solubility were as follows, and evaluations A and B were considered to be passing. · Evaluation A: Less than 15.0 mass% · Evaluation B: 15.0 mass% or more and less than 18.0 mass% · Evaluation C: 18.0 mass% or more The lower the solubility, the easier it is to suppress the dissolution of the hydrocarbon refrigerant.

[0080] The results are shown in Table 1.

[0081]

Table 1

[0082] From Table 1, the following can be understood. It can be seen that the PAG-based compounds of Examples 1 to 5 have a high dissolution viscosity when the hydrocarbon refrigerant is dissolved and also have a low solubility of the hydrocarbon refrigerant. On the other hand, it can be seen that the PAG-based compound of Comparative Example 1, the mineral oil of Comparative Example 2, and the PAO of Comparative Example 3 have a low dissolution viscosity when the hydrocarbon refrigerant is dissolved and also have a high solubility of the hydrocarbon refrigerant.

Claims

Claim 1 A refrigerant oil composition used for a refrigerant containing a hydrocarbon refrigerant, the refrigerant oil composition containing one or more selected from polyalkylene glycol compounds (A) represented by the following general formula (1). 【Chemical 1】 [In the general formula (1), R １ and R ２ One or both of them are groups represented by the following general formula (2). R １ and R ２ When one of them is a group represented by the following general formula (2), the other is a hydrogen atom or a linear or branched alkyl group having 1 to 16 carbon atoms. E is an ethylene group, and P is a propylene group. m is 0, and n is an integer of 1 or more and 50 or less.] 【Chemical 2】 [In the general formula (2), R ３ is a linear or branched alkyl group having 10 to 22 carbon atoms or a linear or branched alkenyl group having 10 to 22 carbon atoms. In the general formula (1), when both R １ and R ２ are groups represented by the following general formula (2), the two R ３ may be the same or different. The wavy line indicates the bonding site with the oxygen atom in the general formula (1).] Claim 2 In the general formula (1), R １ and R ２ The refrigerant oil composition according to claim 1, wherein both are groups represented by the general formula (2). Claim 3 The refrigerant oil composition according to claim 1 or 2, wherein the content of the polyalkylene glycol compound (A) is 80% by mass or more based on the total amount of the refrigerant oil composition. Claim 4 The refrigerant oil composition according to any one of claims 1 to 3, wherein the hydrocarbon refrigerant is a hydrocarbon having 1 to 8 carbon atoms. Claim 5 A refrigerant mixture composition for a refrigerator, containing the refrigerant oil composition according to any one of claims 1 to 4 and a refrigerant containing a hydrocarbon refrigerant. Claim 6 A method for producing a refrigerant oil composition used for a refrigerant containing a hydrocarbon refrigerant, the method for producing a refrigerant oil composition including a step of blending one or more selected from polyalkylene glycol compounds (A) represented by the following general formula (1). 【Chemical Formula 3】 [In the general formula (1), R １ and R ２ One or both of them are groups represented by the following general formula (2). R １ and R ２ When one of them is a group represented by the following general formula (2), the other is a hydrogen atom or a linear or branched alkyl group having 1 or more and 16 or less carbon atoms. E is an ethylene group, and P is a propylene group. m is 0, and n is an integer of 1 or more and 50 or less. ] 【Chemical Formula 4】 [In the general formula (2), R ３ is a linear or branched alkyl group having 10 to 22 carbon atoms or a linear or branched alkenyl group having 10 to 22 carbon atoms. In the general formula (1), when both R １ and R ２ are groups represented by the following general formula (2), the two R ３ may be the same or different. The wavy line indicates the bonding site with the oxygen atom in the general formula (1). ]

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