Refrigerator oil composition

Abstract

Provided is a refrigerator oil composition which contains a fluorescent compound (A) represented by general formula (a-1) (in the formula, R1 and R2 each independently represent an alkyl group having two or more carbon atoms or an alkenyl group having two or more carbon atoms), and a base oil (B), and in which the contained amount of component (A) with respect to the total amount of the refrigerator oil composition is 0.60 mass% or more.

Description

Refrigerating machine oil composition

[0001] The present invention relates to a refrigerator oil composition, a mixed composition for a refrigerator, and a leak detection method.

[0002] Air conditioning systems and cooling systems use various refrigerants, but there is a possibility that the refrigerant may leak outside during use. Therefore, it is necessary to identify the location of the refrigerant leak. Recently, refrigerant leak detection methods using fluorescent agents have been developed. For example, Patent Document 1 discloses a configuration in which a fluorescent agent for refrigerant leak detection is disposed in a receiver dryer used in the refrigeration cycle of a car air conditioner. In this configuration, the fluorescent dye from the fluorescent agent decomposes when mixed with the compressor lubricating oil mixed in the refrigerant, turning into fine particles that are mixed into the refrigerant.

[0003] Japanese Patent Application Laid-Open No. 2006-52938

[0004] However, the refrigerant leak detection method using a fluorescent material as described in Patent Document 1 can detect a large amount of refrigerant leak by irradiating it with ultraviolet light, but it is difficult to detect small leaks. Furthermore, when a fluorescent agent is blended into a refrigerating machine oil composition, depending on the type of fluorescent agent, mixing it with the refrigerant can cause a decrease in compatibility with the refrigerant or a decrease in thermal stability. Therefore, there is a need for a refrigerating machine oil composition and a leak detection method that have various favorable properties when mixed with the refrigerant and can easily detect even small leaks.

[0005] As a result of extensive research, the present inventors have found that a refrigerator oil composition containing a predetermined amount of a fluorescent compound having a specific structure can solve the above-mentioned problems. Specifically, the present invention discloses the following aspects. [1] A refrigerating machine oil composition comprising a fluorescent compound represented by the following general formula (a-1): (In the above formula, R １ and R ２and each independently represent an alkyl group having 2 or more carbon atoms or an alkenyl group having 2 or more carbon atoms.) and a base oil (B), wherein the content of component (A) is 0.60 mass% or more based on the total amount of the refrigerating oil composition. [2] The refrigerating oil composition according to the above item [1], wherein the content of component (A) is 1.00 mass% or more based on the total amount of the refrigerating oil composition. [3] The refrigerating oil composition according to the above item [1], wherein R in the general formula (a-1) １ and R ２is an ethyl group. [4] The refrigerating oil composition according to any one of the above [1] to [3], wherein component (B) comprises one or more selected from polyvinyl ethers (PVE), polyalkylene glycols (PAG), polyol esters (POE), and mineral oil. [5] The refrigerating oil composition according to any one of the above [1] to [4], wherein component (B) comprises one or more selected from polyvinyl ethers (PVE) and polyalkylene glycols (PAG). [6] The refrigerating oil composition according to any one of the above [1] to [5], wherein component (B) comprises one or more refrigerants selected from the group consisting of fluorohydrocarbon refrigerants, hydrocarbon (HC) refrigerants which are natural refrigerants, carbon dioxide, and ammonia. [7] The refrigerating machine oil composition according to any one of the above [1] to [5], which is mixed with one or more refrigerants selected from the group consisting of a fluorocarbon refrigerant, a hydrocarbon (HC) refrigerant which is a natural refrigerant, carbon dioxide, and ammonia, and circulates through the piping of a refrigeration and air conditioning equipment. [8] A refrigerating machine oil composition according to any one of the above [1] to [7], which is mixed with one or more refrigerants selected from the group consisting of a fluorocarbon refrigerant, a hydrocarbon (HC) refrigerant which is a natural refrigerant, carbon dioxide, and ammonia. [9] A method for detecting leakage of a refrigerating machine mixed composition circulating through a pipe of a refrigeration and air conditioning equipment, wherein the refrigerating machine mixed composition is a mixture of the refrigerating machine oil composition according to any one of the above [1] to [7] and one or more refrigerants selected from the group consisting of a fluorohydrocarbon refrigerant, a hydrocarbon (HC) refrigerant which is a natural refrigerant, carbon dioxide, and ammonia, and the leakage detection method comprises irradiating ultraviolet light from the outside of the pipe, and confirming leakage of the refrigerating machine mixed composition from the pipe based on the presence or absence of light emission.

[0006] The refrigerating machine oil composition according to a preferred embodiment of the present invention has various favorable properties (e.g., thermal stability and compatibility with the refrigerant) when mixed with the refrigerant, and also makes it easy to detect even a small leak. Therefore, the refrigerating machine oil composition is suitable for use in applications where the refrigerating machine oil composition is mixed with the refrigerant and circulated through the piping of a refrigeration / air-conditioning device.

[0007] Regarding the numerical ranges described herein, the upper and lower limits can be arbitrarily combined. For example, when a numerical range is described as "preferably 30 to 100, more preferably 40 to 80," the ranges "30 to 80" and "40 to 100" are also included in the numerical ranges described herein. Furthermore, when a numerical range is described as "preferably 30 or more, more preferably 40 or more, and preferably 100 or less, more preferably 80 or less," the ranges "30 to 80" and "40 to 100" are also included in the numerical ranges described herein. In other words, when specifying the upper and lower limits described herein, the numerical range from the lower limit to the upper limit can be specified by appropriately selecting from the respective options and combining them arbitrarily. Furthermore, as a numerical range described herein, for example, "60 to 100" means a range of "60 or more (more than 60) and 100 or less (less than 100)." In addition, multiple combinations of the various requirements described as preferred aspects described herein can be used.

[0008] [Configuration of Refrigerator Oil Composition] A refrigerator oil composition according to one embodiment of the present invention contains a fluorescent compound (A) represented by general formula (a-1) (hereinafter also referred to as "component (A)") and a base oil (B) (hereinafter also referred to as "component (B)").

[0009] Various refrigerants are used in refrigeration and air conditioning equipment, and there is a possibility that the refrigerant may leak to the outside during use. To date, the use of fluorescent agents (fluorescent compounds) has been considered to facilitate refrigerant leak detection. However, while conventional leak detection methods using fluorescent agents (fluorescent compounds) can detect large amounts of refrigerant leaking, they are difficult to detect early leaks, such as those caused by tiny cracks in the piping. In particular, in the case of large refrigeration and air conditioning equipment, such as multi-air conditioning systems for buildings, extensive monitoring is required, making it difficult to monitor over a long period of time, making it difficult to detect such early leaks. Furthermore, when a refrigerating machine oil composition containing a fluorescent agent (fluorescent compound) is mixed with a refrigerant and circulated through the piping of a refrigeration and air conditioning equipment, depending on the type of fluorescent agent, poor compatibility with the refrigerant may result in separation or a decrease in thermal stability. In response to these problems, the refrigerator oil composition of one embodiment of the present invention contains 0.60 mass % or more of the fluorescent compound (A) represented by general formula (a-1), thereby adjusting the refrigerator oil composition to have good thermal stability and compatibility with the refrigerant when mixed with the refrigerant, and to be able to emit strong light even when used in a small amount (for example, one drop (0.01 to 0.10 mL)).

[0010] The refrigerator oil composition of one embodiment of the present invention may further contain various additives within a range that does not impair the effects of the present invention. However, in the refrigerator oil composition of one embodiment of the present invention, the total content of components (A) and (B) may be 50 mass% or more, 60 mass% or more, 65 mass% or more, 70 mass% or more, 75 mass% or more, 80 mass% or more, 85 mass% or more, 90 mass% or more, 95 mass% or more, 97 mass% or more, 99 mass% or more, or 100 mass% based on the total amount (100 mass%) of the refrigerator oil composition. Hereinafter, each component contained in the refrigerator oil composition of one embodiment of the present invention will be described.

[0011] <Component (A): Fluorescent Compound> Component (A) used in one embodiment of the present invention is a fluorescent compound represented by the following general formula (a-1).

[0012] In the general formula (a-1), R １ and R ２each independently represents an alkyl group having 2 or more carbon atoms or an alkenyl group having 2 or more carbon atoms. By containing a fluorescent compound having the above structure, it is possible to prepare a refrigerating machine oil composition that, when mixed with a refrigerant, improves thermal stability and compatibility with the refrigerant, and is capable of emitting strong light when irradiated with ultraviolet light even in a small amount (for example, 1 drop (0.01 to 0.10 mL)).

[0013] R １ and R ２ Examples of the alkyl group that can be selected as the alkyl group include an ethyl group, a propyl group (n-propyl group, isopropyl group), a butyl group (n-butyl group, s-butyl group, t-butyl group, isobutyl group), a pentyl group, a hexyl group, a 2-ethylhexyl 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 hexadecyl group, an octadecyl group, etc., and may be a linear alkyl group or a branched alkyl group. The alkyl group preferably has 2 to 20, 2 to 16, 2 to 12, 2 to 10, 2 to 8, 2 to 6, 2 to 4, 2 to 3, or 2 carbon atoms.

[0014] R １ and R ２ Examples of the alkenyl group that can be selected as are ethenyl, propenyl, butenyl, pentenyl, hexenyl, heptenyl, octenyl, nonenyl, decenyl, undecenyl, dodecenyl, tridecenyl, tetradecenyl, pentadecenyl, hexadecenyl, and octadecenyl groups, and may be linear or branched alkenyl groups. The alkenyl group preferably has 2 to 20, 2 to 16, 2 to 12, 2 to 10, 2 to 8, 2 to 6, 2 to 4, 2 to 3, or 2 carbon atoms.

[0015] Among these, from the viewpoint of adjusting a refrigerating machine oil composition having improved thermal stability and compatibility with a refrigerant when mixed with the refrigerant, R １ and R ２is preferably an alkyl group having 2 or more carbon atoms, more preferably an alkyl group having 2 to 6 carbon atoms, and even more preferably an ethyl group. １ and R ２ is an ethyl group, is preferably contained in an amount of 40 to 100 mass%, 50 to 100 mass%, 60 to 100 mass%, 70 to 100 mass%, 80 to 100 mass%, 90 to 100 mass%, 95 to 100 mass%, 98 to 100 mass%, or 100 mass% based on the total amount (100 mass%) of component (A).

[0016] In a refrigerator oil composition according to one embodiment of the present invention, the content of component (A) is 0.60% by mass or more, based on the total amount (100% by mass) of the refrigerator oil composition. By setting the content of component (A) to 0.60% by mass or more, it is possible to prepare a refrigerator oil composition that can emit strong light when irradiated with ultraviolet light, even in a small amount (for example, one drop (0.01 to 0.10 mL)). On the other hand, a refrigerator oil composition with a content of component (A) of less than 0.60% by mass is unlikely to emit light sufficiently to be visually detectable when irradiated with ultraviolet light, even in a small amount such as one drop (0.01 to 0.10 mL).

[0017] From the above viewpoints, in the refrigerator oil composition of one embodiment of the present invention, the content of component (A) is preferably 0.65 mass % or more, 0.70 mass % or more, 0.75 mass % or more, 0.80 mass % or more, 0.85 mass % or more, 0.90 mass % or more, 0.95 mass % or more, or 1.00 mass % or more, based on the total amount (100 mass %) of the refrigerator oil composition. Furthermore, from the viewpoint of adjusting the refrigerating oil composition to have improved thermal stability and compatibility with the refrigerant when mixed with a refrigerant, the content of component (A) in the refrigerating oil composition of one embodiment of the present invention may be 5.00 mass% or less, 4.50 mass% or less, 4.00 mass% or less, 3.50 mass% or less, 3.00 mass% or less, 2.50 mass% or less, 2.00 mass% or less, 1.50 mass% or less, 1.40 mass% or less, 1.30 mass% or less, 1.20 mass% or less, or 1.10 mass% or less, based on the total amount (100 mass%) of the refrigerating oil composition.

[0018] <Fluorescent Compound Other Than Component (A)> The refrigerating machine oil composition of one embodiment of the present invention may further contain a fluorescent compound other than component (A) within a range that does not impair the effects of the present invention. However, from the viewpoint of preparing a refrigerating machine oil composition that has improved thermal stability and compatibility with the refrigerant when mixed with the refrigerant, and from the viewpoint of preparing a refrigerating machine oil composition that can emit strong light when irradiated with ultraviolet light even in a small amount (for example, one drop (0.01 to 0.10 mL)), the content of the fluorescent compound other than component (A) is preferably as small as possible.

[0019] In the refrigerator oil composition of one embodiment of the present invention, the content of fluorescent compounds other than component (A) may be less than 1.00 mass%, less than 0.50 mass%, less than 0.10 mass%, less than 0.05 mass%, less than 0.01 mass%, less than 0.001 mass%, or less than 0.0001 mass%, based on the total amount (100 mass%) of the refrigerator oil composition.

[0020] The content of fluorescent compounds other than component (A) may be less than 10 parts by mass, less than 5.0 parts by mass, less than 1.0 part by mass, less than 0.5 parts by mass, less than 0.1 part by mass, less than 0.01 part by mass, or less than 0.001 part by mass, relative to 100 parts by mass of the total amount of component (A) contained in the refrigerating machine oil composition.

[0021] <Component (B): Base Oil> The refrigerator oil composition of one embodiment of the present invention contains a base oil as component (B). In the refrigerator oil composition of one embodiment of the present invention, the content of component (B) is preferably 50% by mass or more, 55% by mass or more, 60% by mass or more, 65% by mass or more, 70% by mass or more, 75% by mass or more, 80% by mass or more, 85% by mass or more, 90% by mass or more, 95.0% by mass or more, 96.0% by mass or more, 97.0% by mass or more, 97.5% by mass or more, 98.0% by mass or more, 98.5% by mass or more, or 99.0% by mass or more, based on the total amount (100% by mass) of the refrigerator oil composition, and may also be 99.4% by mass or less, 99.3% by mass or less, 99.2% by mass or less, 99.1% by mass or less, 99.0% by mass or less, 98.0% by mass or less, 97.0% by mass or less, 96.0% by mass or less, or 95.0% by mass or less.

[0022] The kinematic viscosity at 40°C of the component (B) used in one embodiment of the present invention is 10 mm ２ / s or more, 15mm ２ / s or more, 20mm ２ / s or more, 25mm ２ / s or more, 30mm ２ / s or more, 35mm ２ / s or more, 40mm ２ / s or more, 45mm ２ / s or more, 50mm ２ / s or more, 55mm ２ / s or more, or 60 mm ２ / s or more, and ２ / s or less, 140mm ２ / s or less, 130mm ２ / s or less, 120mm ２ / s or less, 110mm ２ / s or less, 100mm ２ / s or less, 90mm ２ / s or less, 85mm ２ / s or less, 80mm ２ / s or less, 75mm ２ / s or less, or 70 mm ２ It is preferable to set the value to / s or less.

[0023] The kinematic viscosity at 100°C of the component (B) used in one embodiment of the present invention is 2.0 mm ２ / s or more, 4.0mm ２ / s or more, 6.0mm ２ / s or more, 6.5mm ２ / s or more, 7.0mm ２ / s or more, 7.5mm ２ / s or more, 8.0mm ２ / s or more, 8.5mm ２ / s or more, 9.0mm ２ / s or more, 10.0mm ２ / s or more, 11.0mm ２ / s or more, 12.0mm ２ / s or more, or 13.0 mm ２ / s or more, and 25.0 mm ２ / s or less, 20.0mm ２ / s or less, 18.0mm ２ / s or less, 16.0mm ２ / s or less, 15.0mm ２ / s or less, 14.0mm ２ / s or less, 13.0mm ２ / s or less, 12.0mm ２ / s or less, 11.0mm ２ / s or less, 10.0mm ２ / s or less, or 9.0 mm ２ It is preferable to set the value to / s or less.

[0024] The viscosity index of component (B) used in one embodiment of the present invention is preferably 70 or more, 80 or more, or 90 or more, and may be 300 or less, 270 or less, 250 or less, or 220 or less.

[0025] Component (B) used in one embodiment of the present invention may be one or more selected from synthetic oils and mineral oils used in refrigerating machine oil applications, but from the viewpoint of adjusting a refrigerating machine oil composition that has improved thermal stability and compatibility with the refrigerant when mixed with the refrigerant, it preferably contains one or more selected from polyvinyl ethers (PVE), polyalkylene glycols (PAG), polyol esters (POE), and mineral oil, and more preferably contains one or more selected from polyvinyl ethers (PVE) and polyalkylene glycols (PAG). PVE, PAG, POE, and mineral oil will be described in detail below.

[0026] [Polyvinyl ethers (PVE)] The polyvinyl ethers (PVE) used in one embodiment of the present invention may be polymers having one or more structural units derived from vinyl ether. The PVE may be used alone or in combination of two or more types. Among such PVEs, from the viewpoint of compatibility with the refrigerant, polymers having one or more structural units derived from vinyl ether and having an alkyl group having 1 to 4 carbon atoms in the side chain are preferred. From the viewpoint of further improving compatibility with the refrigerant, the alkyl group is preferably a methyl group or an ethyl group, and more preferably a methyl group.

[0027] Furthermore, the PVE used in one embodiment of the present invention is preferably a polymer (B-1) having one or more structural units represented by the following general formula (b-1).

[0028] In the above general formula (b-1), R １ａ , R ２ａ , and R ３ａ R each independently represents a hydrogen atom or a hydrocarbon group having 1 to 8 carbon atoms. ４ａ represents a divalent hydrocarbon group having 2 to 10 carbon atoms. ５ａ represents a hydrocarbon group having 1 to 10 carbon atoms. ４ａ The number of repeating units represented by the general formula (b-1) is 0 to 10, preferably 0 to 5, more preferably 0 to 3, and even more preferably 0. ４ａ If there are multiple, multiple OR ４ａ may be the same or different.

[0029] R １ａ , R ２ａ , and R ３ａ Examples of hydrocarbon groups having 1 to 8 carbon atoms that can be selected as include alkyl groups such as methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, sec-butyl, tert-butyl, various pentyl groups, various hexyl groups, various heptyl groups, and various octyl groups; cycloalkyl groups such as cyclopentyl, cyclohexyl, various methylcyclohexyl groups, various ethylcyclohexyl groups, and various dimethylcyclohexyl groups; aryl groups such as phenyl, various methylphenyl groups, various ethylphenyl groups, and various dimethylphenyl groups; arylalkyl groups such as benzyl, various phenylethyl groups, and various methylbenzyl groups; etc. The number of carbon atoms in the hydrocarbon group is preferably 1 to 6, and more preferably 1 to 3.

[0030] R １ａ , R ２ａ , and R ３ａ are each independently preferably a hydrogen atom or an alkyl group having 1 to 8 carbon atoms, more preferably a hydrogen atom or an alkyl group having 1 to 3 carbon atoms. １ａ , R ２ａ , and R ３ａmay be the same or different.

[0031] R ４ａ Examples of divalent hydrocarbon groups having 2 to 10 carbon atoms that can be selected as R include divalent aliphatic groups such as ethylene, 1,2-propylene, 1,3-propylene, various butylene groups, various pentylene groups, various hexylene groups, various heptylene groups, various octylene groups, various nonylene groups, and various decylene groups; divalent alicyclic groups such as cyclohexane, methylcyclohexane, ethylcyclohexane, dimethylcyclohexane, and propylcyclohexane; divalent aromatic groups such as various phenylene groups, various methylphenylene groups, various ethylphenylene groups, various dimethylphenylene groups, and various naphthylenes; divalent alkylaromatic groups having monovalent bonding sites at the alkyl group moiety and aromatic moiety of alkylaromatic hydrocarbons such as toluene, xylene, and ethylbenzene; and divalent alkylaromatic groups having a bonding site at the alkyl group moiety of polyalkylaromatic hydrocarbons such as xylene and diethylbenzene. The number of carbon atoms in the hydrocarbon group is preferably 2 to 6, and more preferably 2 to 4. ４ａ is preferably a divalent aliphatic group having 2 to 10 carbon atoms, more preferably a divalent aliphatic group having 2 to 4 carbon atoms.

[0032] R ５ａExamples of hydrocarbon groups having 1 to 10 carbon atoms that can be selected as R include alkyl groups such as methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, sec-butyl, tert-butyl, various pentyl groups, various hexyl groups, various heptyl groups, various octyl groups, various nonyl groups, and various decyl groups; cycloalkyl groups such as cyclopentyl, cyclohexyl, various methylcyclohexyl groups, various ethylcyclohexyl groups, various propylcyclohexyl groups, and various dimethylcyclohexyl groups; aryl groups such as phenyl, various methylphenyl groups, various ethylphenyl groups, various dimethylphenyl groups, various propylphenyl groups, various trimethylphenyl groups, various butylphenyl groups, and various naphthyl groups; and arylalkyl groups such as benzyl, various phenylethyl groups, various methylbenzyl groups, various phenylpropyl groups, and various phenylbutyl groups. ５ａ The number of carbon atoms in the hydrocarbon group that can be selected as R is preferably 1 to 8, more preferably 1 to 6. ５ａ From the viewpoint of further improving compatibility with the refrigerant, the alkyl group is preferably an alkyl group having 1 to 6 carbon atoms, more preferably an alkyl group having 1 to 4 carbon atoms, still more preferably a methyl group or an ethyl group, and still more preferably a methyl group.

[0033] The number of units (degree of polymerization) of the structural unit represented by the general formula (b-1) is appropriately selected depending on the kinematic viscosity required for the base oil (B). Furthermore, the polymer having the structural unit represented by the general formula (b-1) may be a homopolymer having only one type of the structural unit, or a copolymer having two or more types of the structural unit. When the polymer is a copolymer, the form of copolymerization is not particularly limited, and may be any of a block copolymer, a random copolymer, or a graft copolymer.

[0034] A monovalent group derived from a saturated hydrocarbon, ether, alcohol, ketone, amide, nitrile, etc. may be introduced into the terminal portion of the polymer (B-1). Among these, it is preferable that one terminal portion of the polymer (B-1) is a group represented by the following general formula (b-1-i):

[0035] In the general formula (b-1-i), * indicates the bonding position to the carbon atom in the structural unit represented by the general formula (b-1). ６ａ , R ７ａ , and R ８ａ are each independently a hydrogen atom or a hydrocarbon group having 1 to 8 carbon atoms, preferably a hydrogen atom or a hydrocarbon group having 1 to 6 carbon atoms, and more preferably a hydrogen atom or an alkyl group having 1 to 3 carbon atoms. ６ａ , R ７ａ , and R ８ａ may be the same or different. ６ａ , R ７ａ , and R ８ａ The hydrocarbon group having 1 to 8 carbon atoms that can be selected as R １ａ , R ２ａ , and R ３ａ The hydrocarbon groups having 1 to 8 carbon atoms that can be selected from the group 1 include the same groups as those listed above.

[0036] In the above general formula (b-1-i), R ９ａ represents a divalent hydrocarbon group having 2 to 10 carbon atoms, preferably a divalent hydrocarbon group having 2 to 6 carbon atoms, and more preferably a divalent aliphatic group having 2 to 4 carbon atoms. ９ａ and represents an integer of 0 to 10, preferably an integer of 0 to 5, more preferably an integer of 0 to 3, and even more preferably 0. In addition, if the repeating unit represented by the general formula (b-1-i) contains OR ９ａ If there are multiple, multiple OR ９ａ may be the same or different. ９ａ The divalent hydrocarbon group having 2 to 10 carbon atoms that can be selected as R ４ａ The divalent hydrocarbon group having 2 to 10 carbon atoms that can be selected from the group 1 and 2 can be the same as those listed above.

[0037] In the above general formula (b-1-i), R １０ａ represents a hydrocarbon group having 1 to 10 carbon atoms, preferably a hydrocarbon group having 1 to 8 carbon atoms, and more preferably an alkyl group having 1 to 8 carbon atoms.１０ａ When r1 in the general formula (b-1-i) is 0, an alkyl group having 1 to 6 carbon atoms is preferable, and when r1 is 1 or more, an alkyl group having 1 to 4 carbon atoms is preferable. １０ａ The hydrocarbon group having 1 to 10 carbon atoms that can be selected as R ５ａ The hydrocarbon groups having 1 to 10 carbon atoms that can be selected for the group include the same groups as those listed above.

[0038] Furthermore, with regard to polymer (B-1), when one end moiety is a group represented by general formula (b-1-i) above, the other end moiety is preferably any one of a group represented by general formula (b-1-i) above, a group represented by general formula (b-1-ii) below, a group represented by general formula (b-1-iii) below, and a group having an olefinically unsaturated bond:

[0039] In the above general formulas (b-1-ii) and (b-1-iii), R ６ａ , R ７ａ , R ８ａ , R ９ａ , R １０ａ , and r1 are the same as defined in the general formula (b-1-i). １１ａ , R １２ａ , and r2 are each R in the general formula (b-1-i). ９ａ , R １０ａ , and the definition of r1 is the same.

[0040] The kinematic viscosity at 40°C of the PVE used in one embodiment of the present invention is 10 mm ２ / s or more, 15mm ２ / s or more, 20mm ２ / s or more, 25mm ２ / s or more, 30mm ２ / s or more, 35mm ２ / s or more, 40mm ２ / s or more, 45mm ２ / s or more, 50mm ２ / s or more, 55mm ２ / s or more, or 60 mm ２ / s or more, and２ / s or less, 140mm ２ / s or less, 130mm ２ / s or less, 120mm ２ / s or less, 110mm ２ / s or less, 100mm ２ / s or less, 90mm ２ / s or less, 85mm ２ / s or less, 80mm ２ / s or less, 75mm ２ / s or less, or 70 mm ２ It is preferable to set the value to / s or less.

[0041] The kinematic viscosity at 100°C of the PVE used in one embodiment of the present invention is 2.0 mm ２ / s or more, 4.0mm ２ / s or more, 6.0mm ２ / s or more, 6.5mm ２ / s or more, 7.0mm ２ / s or more, 7.5mm ２ / s or more, or 8.0 mm ２ / s or more, and 25.0 mm ２ / s or less, 20.0mm ２ / s or less, 18.0mm ２ / s or less, 16.0mm ２ / s or less, 15.0mm ２ / s or less, 14.0mm ２ / s or less, 13.0mm ２ / s or less, 12.0mm ２ / s or less, 11.0mm ２ / s or less, 10.0mm ２ / s or less, or 9.0 mm ２ It is preferable to set the value to / s or less.

[0042] The viscosity index of the PVE used in one embodiment of the present invention is preferably 70 or more, 75 or more, 80 or more, 85 or more, or 90 or more, or may be 300 or less, 270 or less, 250 or less, 220 or less, 200 or less, 150 or less, 130 or less, 120 or less, 110 or less, or 100 or less.

[0043] [Polyalkylene glycols (PAG)] The polyalkylene glycols (PAG) used in one embodiment of the present invention are preferably polymers (B-b) represented by the following general formula (b-2). The PAGs may be used alone or in combination of two or more. R １ｂ - [(OR ２ｂ ) ｍ -OR ３ｂ ] ｎ (b-2)

[0044] In the above general formula (b-2), R １ｂ represents a hydrogen atom, a monovalent hydrocarbon group having 1 to 10 carbon atoms, an acyl group having 2 to 10 carbon atoms, a divalent to hexavalent hydrocarbon group having 1 to 10 carbon atoms, or a substituted or unsubstituted heterocyclic group having 3 to 10 ring atoms. ２ｂ represents an alkylene group having 2 to 4 carbon atoms. ３ｂ represents a hydrogen atom, a monovalent hydrocarbon group having 1 to 10 carbon atoms, an acyl group having 2 to 10 carbon atoms, or a substituted or unsubstituted heterocyclic group having 3 to 10 ring atoms. Examples of substituents that the heterocyclic group may have include an alkyl group having 1 to 10 carbon atoms (preferably 1 to 6, more preferably 1 to 3); a cycloalkyl group having 3 to 10 ring carbon atoms (preferably 3 to 8, more preferably 5 or 6); an aryl group having 6 to 18 ring carbon atoms (preferably 6 to 12); a halogen atom (a fluorine atom, a chlorine atom, a bromine atom, an iodine atom); a cyano group; a nitro group; a hydroxy group; an amino group, and the like. These substituents may be further substituted with any of the substituents described above.

[0045] n is an integer of 1 to 6, preferably an integer of 1 to 3, and more preferably 1. Note that n is the same as R １ｂ For example, R １ｂ When R is an alkyl group or an acyl group, n is 1, and R １ｂ is a hydrocarbon group or a heterocyclic group, and when the valence of the group is divalent, trivalent, tetravalent, pentavalent, or hexavalent, n is 2, 3, 4, 5, or 6, respectively. ２ｂThe number of repeating units of the formula (I) is 1 or more, and preferably m×n is a number such that m×n is 6 to 80. The value of m is appropriately set so that the kinematic viscosity of component (B) at 100°C falls within a predetermined range, and there are no particular restrictions on the value of m as long as the kinematic viscosity is adjusted to fall within the predetermined range. ２ｂ may be the same or different. When n is 2 or more, multiple R ３ｂ may be the same as or different from each other.

[0046] R １ｂ and R ３ｂ Examples of the monovalent hydrocarbon group that can be selected include alkyl groups such as methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, sec-butyl, tert-butyl, various pentyl groups, various hexyl groups, various heptyl groups, various octyl groups, various nonyl groups, and various decyl groups; cycloalkyl groups such as cyclopentyl, cyclohexyl, various methylcyclohexyl groups, various ethylcyclohexyl groups, various propylcyclohexyl groups, and various dimethylcyclohexyl groups; aryl groups such as phenyl, various methylphenyl groups, various ethylphenyl groups, various dimethylphenyl groups, various propylphenyl groups, various trimethylphenyl groups, various butylphenyl groups, and various naphthyl groups; and arylalkyl groups such as benzyl, various phenylethyl groups, various methylbenzyl groups, various phenylpropyl groups, and various phenylbutyl groups. The alkyl groups may be either straight-chain or branched. The number of carbon atoms in the monovalent hydrocarbon group is preferably 1 to 10, more preferably 1 to 6, and even more preferably 1 to 3, from the viewpoint of compatibility with the refrigerant.

[0047] R １ｂ and R ３ｂ The hydrocarbon group moiety of the acyl group having 2 to 10 carbon atoms that can be selected as R may be any of linear, branched, and cyclic. １ｂ and R ３ｂAmong the hydrocarbon groups that can be selected as the acyl group, those having 1 to 9 carbon atoms can be mentioned. From the viewpoint of compatibility with the refrigerant, the number of carbon atoms in the acyl group is preferably 2 to 10, more preferably 2 to 6.

[0048] R １ｂ The divalent to hexavalent hydrocarbon group that can be selected as R １ｂ Examples of the acyl group include residues obtained by removing 1 to 5 hydrogen atoms from a monovalent hydrocarbon group, and residues obtained by removing a hydroxyl group from a polyhydric alcohol such as trimethylolpropane, glycerin, pentaerythritol, sorbitol, 1,2,3-trihydroxycyclohexane, or 1,3,5-trihydroxycyclohexane. From the viewpoint of compatibility with the refrigerant, the carbon number of the divalent to hexavalent acyl group is preferably 2 to 10, and more preferably 2 to 6.

[0049] R １ｂ and R ３ｂ The heterocyclic group that can be selected from the above is preferably an oxygen atom-containing heterocyclic group or a sulfur atom-containing heterocyclic group. The heterocyclic group may be a saturated ring or an unsaturated ring. Examples of the oxygen atom-containing heterocyclic group include residues in which 1 to 6 hydrogen atoms have been removed from oxygen atom-containing saturated heterocycles such as ethylene oxide, 1,3-propylene oxide, tetrahydrofuran, tetrahydropyran, and hexamethylene oxide, and oxygen atom-containing unsaturated heterocycles such as acetylene oxide, furan, pyran, oxycycloheptatriene, isobenzofuran, and isochromene. Examples of the sulfur atom-containing heterocyclic group include residues in which 1 to 6 hydrogen atoms have been removed from sulfur atom-containing saturated heterocycles such as ethylene sulfide, trimethylene sulfide, tetrahydrothiophene, tetrahydrothiopyran, and hexamethylene sulfide, and sulfur atom-containing unsaturated heterocycles such as acetylene sulfide, thiophene, thiapyran, and thiotripyridene.

[0050] Also, R １ｂ and R ３ｂThe heterocyclic group, which may be selected from the above, may have a substituent, and the substituent may be bonded to the oxygen atom in the general formula (b-2). As the substituent, as described above, an alkyl group having 1 to 6 carbon atoms is preferred, and an alkyl group having 1 to 3 carbon atoms is more preferred. From the viewpoint of compatibility with the refrigerant, the number of ring atoms of the heterocyclic group is preferably 3 to 10, more preferably 3 to 6.

[0051] R ２ｂ The alkylene group that can be selected as ２ CH ２ -), ethylene group (-CH(CH ３ an alkylene group having 2 carbon atoms, such as a trimethylene group (—CH ２ CH ２ CH ２ -), propylene group (-CH(CH ３ ) CH ２ -), propylidene group (-CHCH ２ CH ３ -), and isopropylidene group (-C(CH ３ ) ２ an alkylene group having 3 carbon atoms, such as a tetramethylene group (—CH ２ CH ２ CH ２ CH ２ -), 1-methyltrimethylene group (-CH(CH ３ ) CH ２ CH ２ -), 2-methyltrimethylene group (-CH ２ CH (CH ３ ) CH ２ -), and butylene group (-C(CH ３ ) ２ CH ２ Examples of alkylene groups include alkylene groups having 4 carbon atoms, such as R ２ｂ If there are multiple R ２ｂ may be the same as each other, or may be a combination of two or more alkylene groups. ２ｂ is a propylene group (-CH(CH ３ ) CH ２ -) is preferred.

[0052] In the polymer (B-2) represented by the general formula (b-2), the oxypropylene unit (—OCH(CH ３ ) CH ２ The content of oxyalkylene (OR -) in the polymer (B-2) ２ｂ ) is preferably 50 mol % or more, more preferably 65 mol % or more, and even more preferably 80 mol % or more, based on the total amount (100 mol %) of the copolymers.

[0053] Among the polymers (B-2) represented by the general formula (b-2), at least one selected from the group consisting of polyoxypropylene glycol dimethyl ether represented by the following general formula (b-2-i), polyoxyethylene polyoxypropylene glycol dimethyl ether represented by the following general formula (b-2-ii), polyoxypropylene glycol monobutyl ether represented by the following general formula (b-2-iii), and polyoxypropylene glycol diacetate is preferred.

[0054] (In the above formula (B-2-i), m1 represents a number of 1 or more, preferably 6 to 80.)

[0055] (In the above formula (B-2-ii), m2 and m3 each independently represent a number of 1 or more, and preferably a number such that the value of m2+m3 is 6 to 80.)

[0056] (In the above formula (B-2-iii), m4 represents a number of 1 or more, and preferably a number of 6 to 80.)

[0057] Note that m1 in the above formula (B-2-i), m2 and m3 in the above formula (B-2-ii), and m4 in the above formula (B-2-iii) are appropriately selected depending on the kinematic viscosity required for the base oil (B).

[0058] The kinematic viscosity of the PAG used in one embodiment of the present invention at 40°C is 10 mm ２ / s or more, 15mm ２ / s or more, 20mm ２ / s or more, 25mm ２ / s or more, 30mm ２ / s or more, 35mm ２ / s or more, 40mm ２ / s or more, 45mm ２ / s or more, 50mm ２ / s or more, 55mm ２ / s or more, 60mm ２ / s or more, or 65 mm ２ / s or more, and ２ / s or less, 140mm ２ / s or less, 130mm ２ / s or less, 120mm ２ / s or less, 110mm ２ / s or less, 100mm ２ / s or less, 90mm ２ / s or less, 85mm ２ / s or less, 80mm ２ / s or less, 75mm ２ / s or less, or 70 mm ２ It is preferable to set the value to / s or less.

[0059] The kinematic viscosity at 100°C of the PAG used in one embodiment of the present invention is 2.0 mm ２ / s or more, 4.0mm ２ / s or more, 6.0mm ２ / s or more, 8.0mm ２ / s or more, 9.0mm ２ / s or more, 9.3mm ２ / s or more, 9.5mm ２ / s or more, 10.0mm ２ / s or more, 10.5mm ２ / s or more, 11.0mm ２ / s or more, 11.5mm ２ / s or more, 12.0mm ２ / s or more, 12.5mm ２ / s or more, or 13.0 mm ２ / s or more, and 25.0 mm ２ / s or less, 20.0mm ２ / s or less, 18.0mm ２ / s or less, 16.0mm ２ / s or less, 15.0mm ２ / s or less, or 14.0 mm ２ It is preferable to set the value to / s or less.

[0060] The viscosity index of the PAG used in one embodiment of the present invention is preferably 70 or more, 80 or more, 90 or more, 100 or more, 110 or more, 130 or more, 150 or more, 170 or more, 200 or more, or 210 or more, or may be 300 or less, 270 or less, or 250 or less.

[0061] [Polyol esters (POE)] Examples of polyol esters (POE) used in one embodiment of the present invention include esters of diols or polyols with fatty acids. POEs may be used alone or in combination of two or more. Among these POEs, esters of diols or polyols having 3 to 20 hydroxyl groups with fatty acids having 3 to 20 carbon atoms are preferred.

[0062] Examples of diols include ethylene glycol, 1,3-propanediol, propylene glycol, 1,4-butanediol, 1,2-butanediol, 2-methyl-1,3-propanediol, 1,5-pentanediol, neopentyl glycol, 1,6-hexanediol, 2-ethyl-2-methyl-1,3-propanediol, 1,7-heptanediol, 2-methyl-2-propyl-1,3-propanediol, 2,2-diethyl-1,3-propanediol, 1,8-octanediol, 1,9-nonanediol, 1,10-decanediol, 1,11-undecanediol, and 1,12-dodecanediol.

[0063] Examples of polyols include polyhydric alcohols such as trimethylolethane, trimethylolpropane, trimethylolbutane, di-(trimethylolpropane), tri-(trimethylolpropane), pentaerythritol, di-(pentaerythritol), tri-(pentaerythritol), glycerin, polyglycerin (a dimer to 20-mer of glycerin), 1,3,5-pentanetriol, sorbitol, sorbitan, sorbitol glycerin condensates, adonitol, arabitol, xylitol, and mannitol; sugars such as xylose, arabinose, ribose, rhamnose, glucose, fructose, galactose, mannose, sorbose, cellobiose, maltose, isomaltose, trehalose, sucrose, raffinose, gentianose, and melenitose; and partially etherified products and methyl glucosides (glycoside) thereof. Among these, hindered alcohols such as neopentyl glycol, trimethylolethane, trimethylolpropane, trimethylolbutane, di-(trimethylolpropane), tri-(trimethylolpropane), pentaerythritol, di-(pentaerythritol), and tri-(pentaerythritol) are preferred.

[0064] The carbon number of the fatty acid is preferably 3 or more, more preferably 4 or more, even more preferably 5 or more, and even more preferably 8 or more, from the viewpoint of lubrication performance, and is preferably 20 or less, more preferably 16 or less, even more preferably 12 or less, and even more preferably 10 or less, from the viewpoint of compatibility with the refrigerant. The carbon number of the fatty acid also includes the carbon atom of the carboxy group (—COOH) possessed by the fatty acid. Furthermore, the fatty acid may be either a linear fatty acid or a branched fatty acid, but from the viewpoint of lubrication performance, a linear fatty acid is preferred, and from the viewpoint of hydrolysis stability, a branched fatty acid is preferred. Furthermore, the fatty acid may be either a saturated fatty acid or an unsaturated fatty acid.

[0065] Examples of fatty acids include linear or branched fatty acids such as isobutyric acid, propionic acid, butanoic acid, pentanoic acid, hexanoic acid, heptanoic acid, octanoic acid, nonanoic acid, decanoic acid, undecanoic acid, dodecanoic acid, tridecanoic acid, tetradecanoic acid, pentadecanoic acid, hexadecanoic acid, heptadecanoic acid, octadecanoic acid, nonadecanoic acid, icosanoic acid, and oleic acid, as well as so-called neo acids in which the α carbon atom is quaternary. More specifically, isobutyric acid, valeric acid (n-pentanoic acid), caproic acid (n-hexanoic acid), enanthic acid (n-heptanoic acid), caprylic acid (n-octanoic acid), pelargonic acid (n-nonanoic acid), capric acid (n-decanoic acid), oleic acid (cis-9-octadecenoic acid), isopentanoic acid (3-methylbutanoic acid), 2-methylhexanoic acid, 2-ethylpentanoic acid, 2-ethylhexanoic acid, and 3,5,5-trimethylhexanoic acid are preferred.

[0066] The POE may be a partial ester in which all hydroxyl groups of the polyol remain unesterified, or a complete ester in which all hydroxyl groups are esterified. Also, a mixture of a partial ester and a complete ester may be used, but a complete ester is preferred.

[0067] Among POEs, from the viewpoint of superior hydrolysis stability, esters of hindered alcohols such as neopentyl glycol, trimethylolethane, trimethylolpropane, trimethylolbutane, di-(trimethylolpropane), tri-(trimethylolpropane), pentaerythritol, di-(pentaerythritol), and tri-(pentaerythritol) are preferred, esters of neopentyl glycol, trimethylolethane, trimethylolpropane, trimethylolbutane, and pentaerythritol are more preferred, and from the viewpoint of particularly superior compatibility with refrigerants and hydrolysis stability, esters of pentaerythritol are even more preferred.

[0068] Specific examples of preferred POE include diesters of neopentyl glycol and one or more fatty acids selected from isobutyric acid, valeric acid, caproic acid, enanthic acid, caprylic acid, pelargonic acid, capric acid, oleic acid, isopentanoic acid, 2-methylhexanoic acid, 2-ethylpentanoic acid, 2-ethylhexanoic acid, and 3,5,5-trimethylhexanoic acid; triesters of trimethylolethane and one or more fatty acids selected from isobutyric acid, valeric acid, caproic acid, enanthic acid, caprylic acid, pelargonic acid, capric acid, oleic acid, isopentanoic acid, 2-methylhexanoic acid, 2-ethylpentanoic acid, 2-ethylhexanoic acid, and 3,5,5-trimethylhexanoic acid; triesters of trimethylolpropane and one or more fatty acids selected from isobutyric acid, valeric acid, caproic acid, enanthic acid, caprylic acid, pelargonic acid, capric acid, oleic acid, and isopentanoic acid; Preferred are triesters of one or more fatty acids selected from 2-methylhexanoic acid, 2-ethylpentanoic acid, 2-ethylhexanoic acid, and 3,5,5-trimethylhexanoic acid; triesters of trimethylolbutane and one or more fatty acids selected from isobutyric acid, valeric acid, caproic acid, enanthic acid, caprylic acid, pelargonic acid, capric acid, oleic acid, isopentanoic acid, 2-methylhexanoic acid, 2-ethylpentanoic acid, 2-ethylhexanoic acid, and 3,5,5-trimethylhexanoic acid; and tetraesters of pentaerythritol and one or more fatty acids selected from isobutyric acid, valeric acid, caproic acid, enanthic acid, caprylic acid, pelargonic acid, capric acid, oleic acid, isopentanoic acid, 2-methylhexanoic acid, 2-ethylpentanoic acid, 2-ethylhexanoic acid, and 3,5,5-trimethylhexanoic acid.

[0069] The ester of two or more fatty acids may be a mixture of two or more esters of one fatty acid and a polyol. Among POEs, esters of two or more mixed fatty acids and polyols are preferred from the viewpoints of improving low-temperature properties and compatibility with refrigerants.

[0070] [Mineral Oil] Examples of mineral oils used in one embodiment of the present invention include lubricating oil fractions obtained by atmospheric distillation of paraffinic crude oil, intermediate crude oil, or naphthenic crude oil, or lubricating oil fractions obtained by vacuum distillation of the atmospheric residual oil obtained by the atmospheric distillation, and then refining the lubricating oil fractions by one or more processes such as solvent deasphalting, solvent extraction, hydrocracking, solvent dewaxing, catalytic dewaxing, and hydrorefining, oils produced by isomerizing mineral oil wax, and oils produced by isomerizing GTL wax (gas-to-liquid wax) produced by the Fischer-Tropsch process, etc. Mineral oils may be used alone or in combination of two or more types.

[0071] In one embodiment of the present invention, component (B) preferably comprises one or more base oils (B1) selected from polyvinyl ethers (PVE), polyalkylene glycols (PAG), polyol esters (POE), and mineral oils as the main component, and more preferably one or more base oils (B2) selected from polyvinyl ethers (PVE) and polyalkylene glycols (PAG). The content of base oil (B1) or base oil (B2) in component (B) is preferably 50 mass% or more, 60 mass% or more, 70 mass% or more, 80 mass% or more, or 90 mass% or more based on the total amount (100 mass%) of component (B).

[0072] Component (B) may contain, in addition to base oil (B1) or base oil (B2), other base oils, as long as the effects of the present invention are not impaired. Examples of such other base oils include polyesters, polycarbonates, hydrogenated α-olefin oligomers, alicyclic hydrocarbon compounds, alkylated aromatic hydrocarbon compounds, and synthetic oils such as copolymers (ECPs) of poly(oxy)alkylene glycols or monoethers thereof with polyvinyl ethers, which do not fall under the category of PVE, PAG, or POE. Note that "copolymers (ECPs) of poly(oxy)alkylene glycols or monoethers thereof with polyvinyl ethers" refer to copolymers having structural units derived from poly(oxy)alkylene glycols or monoethers thereof and structural units derived from polyvinyl ethers, and "poly(oxy)alkylene glycols" refer to both polyalkylene glycols and polyoxyalkylene glycols.

[0073] <Various Additives> The refrigerator oil composition of one embodiment of the present invention may further contain various additives within a range that does not impair the effects of the present invention. From the viewpoint of improving the stability of the refrigerator oil composition, such additives include antioxidants, oiliness improvers, acid scavengers, oxygen scavengers, extreme pressure agents, copper deactivators, rust inhibitors, antifoaming agents, and viscosity index improvers. The content of each of these additives, specifically, the antioxidant, oiliness improver, acid scavenger, oxygen scavenger, extreme pressure agent, copper deactivator, rust inhibitor, antifoaming agent, and viscosity index improver, based on the total amount (100 mass%) of the refrigerating machine oil composition, may be 0.001 mass% or more, 0.01 mass% or more, 0.05 mass% or more, 0.1 mass% or more, 0.5 mass% or more, or 1.0 mass% or more, or may be 10 mass% or less, 5.0 mass% or less, 3.0 mass% or less, 2.0 mass% or less, 1.0 mass% or less, 0.50 mass% or less, 0.10 mass% or less, 0.01 mass% or less, or 0.001 mass% or less.

[0074] [Antioxidant] Examples of the antioxidant used in one embodiment of the present invention include one or more selected from phenol-based antioxidants and amine-based antioxidants. Examples of phenol-based antioxidants include 2,6-di-tert-butyl-4-methylphenol (DBPC), 2,6-di-tert-butyl-4-ethylphenol, and 2,2'-methylenebis(4-methyl-6-tert-butylphenol). Examples of amine-based antioxidants include phenyl-α-naphthylamine and N,N'-diphenyl-p-phenylenediamine.

[0075] [Oilability Improver] Examples of the oiliness improver used in one embodiment of the present invention include saturated or unsaturated aliphatic 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; saturated or unsaturated aliphatic monoalcohols such as lauryl alcohol and oleyl alcohol; saturated or unsaturated aliphatic monoamines such as stearylamine and oleylamine; saturated or unsaturated aliphatic monocarboxylic acid amides such as lauric acid amide and oleic acid amide; and partial esters of polyhydric alcohols and saturated or unsaturated aliphatic monocarboxylic acids such as glycerin and sorbitol.

[0076] [Acid Scavenger] Examples of the acid scavenger used in one embodiment of the present invention include epoxy compounds. Examples of the epoxy compounds include glycidyl ether compounds, cyclohexene oxide, α-olefin oxide, and epoxidized soybean oil, with glycidyl ether compounds being preferred. The glycidyl ether compound is preferably one or more selected from the group consisting of aliphatic monoalcohols having 3 to 30 carbon atoms (more preferably 4 to 24, even more preferably 6 to 16), aliphatic polyhydric alcohols having 3 to 30 carbon atoms (more preferably 4 to 24, even more preferably 6 to 16), and glycidyl ethers derived from aromatic compounds containing one or more hydroxyl groups. The aliphatic monoalcohols or aliphatic polyhydric alcohols may be linear, branched, or cyclic, and may be saturated or unsaturated. In addition, in the aliphatic polyhydric alcohols and aromatic compounds containing two or more hydroxyl groups, it is preferred that all of the hydroxyl groups be glycidyl etherified, from the viewpoints of improving the stability of the refrigerating machine oil and suppressing an increase in the hydroxyl value.

[0077] Examples of the glycidyl ether compound include phenyl glycidyl ether, alkyl glycidyl ether, alkylene glycol glycidyl ether, etc. Examples of the glycidyl ether compound include glycidyl ethers derived from linear, branched, or cyclic saturated aliphatic monoalcohols having 6 to 16 carbon atoms (i.e., alkyl glycidyl ethers in which the alkyl group has 6 to 16 carbon atoms), such as 2-ethylhexyl glycidyl ether, isononyl glycidyl ether, decyl glycidyl ether, lauryl glycidyl ether, and myristyl glycidyl ether.

[0078] [Oxygen Scavenger] Examples of oxygen scavengers used in one embodiment of the present invention include aliphatic unsaturated compounds and terpenes having a double bond. The aliphatic unsaturated compounds are preferably unsaturated hydrocarbons, and specific examples include olefins and polyenes such as dienes and trienes. As the olefins, α-olefins such as 1-tetradecene, 1-hexadecene, and 1-octadecene are preferred from the viewpoint of high reactivity with oxygen. Furthermore, as aliphatic unsaturated compounds other than those mentioned above, α-olefins such as 1-tetradecene, 1-hexadecene, and 1-octadecene are preferred from the viewpoint of high reactivity with oxygen. ２０ H ３０ Preferable unsaturated aliphatic alcohols having a conjugated double bond include 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 formula O. As the terpenes having a double bond, preferred are terpene hydrocarbons having a double bond, and from the viewpoint of high 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-methylidendodeca-1,6,10-triene) is more preferred.

[0079] [Extreme Pressure Agents] Examples of extreme pressure agents used in one embodiment of the present invention include phosphorus-based extreme pressure agents, metal salts of carboxylic acids, and sulfur-based extreme pressure agents. Examples of phosphorus-based extreme pressure agents include phosphate esters, acidic phosphate esters, phosphites, acidic phosphites, and amine salts thereof. Among these, from the viewpoint of improving extreme pressure properties and friction characteristics, one or more selected from tricresyl phosphate (TCP), trithiophenyl phosphate, tri(nonylphenyl)phosphite, dioleylhydrogen phosphite, and 2-ethylhexyldiphenyl phosphite are preferred, with tricresyl phosphate (TCP) being more preferred. Examples of metal salts of carboxylic acids include metal salts of carboxylic acids having 3 to 60 carbon atoms (preferably 3 to 30 carbon atoms). Among these, one or more selected from metal salts of fatty acids having 12 to 30 carbon atoms and metal salts of dicarboxylic acids having 3 to 30 carbon atoms are preferred. Furthermore, alkali metals and alkaline earth metals are preferred as metals constituting the metal salts, with alkali metals being more preferred. Examples of sulfur-based extreme pressure agents include sulfurized fats and oils, sulfurized fatty acids, sulfurized esters, sulfurized olefins, dihydrocarbyl polysulfides, thiocarbamates, thioterpenes, and dialkylthiodipropionates.

[0080] [Copper Deactivator] Examples of copper deactivators used in one embodiment of the present invention include N-[N,N'-dialkyl(alkyl group having 3 to 12 carbon atoms)aminomethyl]triazole.

[0081] [Rust inhibitor] Examples of the rust inhibitor used in one embodiment of the present invention include metal sulfonates, aliphatic amines, organic phosphites, organic phosphates, organic sulfonic acid metal salts, organic phosphate metal salts, alkenyl succinic acid esters, and polyhydric alcohol esters.

[0082] [Antifoaming Agent] Examples of the antifoaming agent used in one embodiment of the present invention include silicone-based antifoaming agents such as silicone oil and fluorinated silicone oil.

[0083] [Viscosity Index Improver] Examples of viscosity index improvers used in one embodiment of the present invention include polymethacrylate, polyisobutylene, ethylene-propylene copolymer, and hydrogenated styrene-diene copolymer.

[0084] [Refrigerant to be mixed with refrigerant oil composition] The refrigerant oil composition of one embodiment of the present invention is mixed with a refrigerant and used as a mixed composition for a refrigerant. The mixing ratio of the refrigerant oil composition of one embodiment of the present invention to the refrigerant [refrigerant oil composition / refrigerant] is, in mass ratio, 1 / 99 or more, 5 / 95 or more, 10 / 90 or more, 15 / 85 or more, 20 / 80 or more, 25 / 75 or more, 30 / 70 or more, 35 / 65 or more, 40 / 60 or more, 45 / 55 or more, 50 / 50 or more, 55 / 45 or more, 60 / 40 or more, 65 / 35 or more, 70 / 30 or more, 75 / 25 or more, 80 / 25 or more, 90 / 25 or more, 100 / 25 or more, 110 / 25 or more, 120 / 25 or more, 130 / 25 or more, 140 / 25 or more, 150 / 25 or more, 160 / 25 or more, 170 / 25 or more, 180 / 25 or more, 190 / 25 or more, 200 / 25 or more, 210 / 25 or more, 220 / 25 or more, 230 / 25 or more, 240 / 25 or more, 250 / 25 or more, 260 / 25 or more, 270 / 25 or more, 280 / 25 or more, 290 / 25 or more, 300 / 25 or more, 310 / 25 or more, 320 / 25 or more, 330 / 25 or more, 340 / 25 or more, It may be 0 or more, or 85 / 15 or more, or it may be 99 / 1 or less, 95 / 5 or less, 90 / 10 or less, 85 / 15 or less, 80 / 20 or less, 75 / 25 or less, 70 / 30 or less, 65 / 35 or less, 60 / 40 or less, 55 / 45 or less, 50 / 50 or less, 45 / 55 or less, 40 / 60 or less, 35 / 65 or less, 30 / 70 or less, 25 / 75 or less, 20 / 80 or less, or 15 / 85 or less.

[0085] The refrigerant used in one embodiment of the present invention may be, for example, one or more selected from the group consisting of fluorohydrocarbon refrigerants, hydrocarbon (HC) refrigerants which are natural refrigerants, carbon dioxide, and ammonia.

[0086] <Fluorinated Hydrocarbon Refrigerant> Examples of the fluorohydrocarbon refrigerant used in one embodiment of the present invention include saturated fluorohydrocarbon compounds (HFCs) and unsaturated fluorohydrocarbon compounds (HFOs).

[0087] As the saturated fluorinated hydrocarbon compound, a fluoride of an alkane having 1 to 4 carbon atoms is preferred, a fluoride of an alkane having 1 to 3 carbon atoms is more preferred, and a fluoride of an alkane (methane or ethane) having 1 to 2 carbon atoms is even more preferred. Examples of 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), and 1,1,1,2,2-pentafluoroethane (R125).

[0088] These saturated fluorohydrocarbon compounds may be used alone or in combination of two or more. Examples of combinations of two or more include mixed refrigerants containing two or more saturated fluorohydrocarbon compounds having 1 to 3 carbon atoms, and mixed refrigerants containing two or more saturated fluorohydrocarbon compounds having 1 to 2 carbon atoms. Examples of such mixed refrigerants include a mixture of R32 and R125 (R410A), a mixture of R125, R143a, and R134a (R404A), a mixture of R32, R125, and R134a (R407A, R407C, R407E, etc.), and a mixture of R125 and R143a (R507A).

[0089] Examples of unsaturated fluorohydrocarbon compounds include fluorides of linear or branched chain olefins having 2 to 6 carbon atoms and fluorides of cyclic olefins having 4 to 6 carbon atoms. More specific examples include ethylene having 1 to 3 fluorine atoms introduced, propene having 1 to 5 fluorine atoms introduced, butene having 1 to 7 fluorine atoms introduced, pentene having 1 to 9 fluorine atoms introduced, hexene having 1 to 11 fluorine atoms introduced, cyclobutene having 1 to 5 fluorine atoms introduced, cyclopentene having 1 to 7 fluorine atoms introduced, and cyclohexene having 1 to 9 fluorine atoms introduced. Among these unsaturated fluorohydrocarbon compounds, fluorides of propene are preferred, propene having 3 to 5 fluorine atoms introduced is more preferred, and propene having 4 fluorine atoms introduced is even more preferred. Specifically, 1,3,3,3-tetrafluoropropene (R1234ze) and 2,3,3,3-tetrafluoropropene (R1234yf) are preferred.

[0090] These unsaturated fluorohydrocarbon compounds may be used alone or in combination of two or more, or may be combined with a refrigerant other than an unsaturated fluorohydrocarbon compound. Examples of combinations with refrigerants other than an unsaturated fluorohydrocarbon compound include mixed refrigerants of a saturated fluorohydrocarbon compound and an unsaturated fluorohydrocarbon compound, such as a mixed refrigerant of R32 and R1234yf, or a mixed refrigerant of R32, R1234ze, and R152a (AC5, mixing ratio, for example, 13.23 / 76.20 / 9.96).

[0091] <Natural Refrigerant> The natural refrigerant used in one embodiment of the present invention includes hydrocarbon (HC) refrigerants, carbon dioxide (CO ２), and ammonia, and preferably a hydrocarbon (HC)-based refrigerant. These natural refrigerants may be used alone or in combination of two or more, or may be combined with a refrigerant other than a natural refrigerant. Examples of combinations with refrigerants other than natural refrigerants include mixed refrigerants of natural refrigerants with saturated fluorohydrocarbon compounds and / or unsaturated fluorohydrocarbon compounds, and specific examples include mixed refrigerants of carbon dioxide, R1234ze, and R134a (AC6, mixing ratio, for example, 5.15:79.02:15.41).

[0092] As the hydrocarbon (HC) refrigerant, hydrocarbons having 1 to 8 carbon atoms are preferred, hydrocarbons having 1 to 5 carbon atoms are more preferred, and hydrocarbons having 3 to 5 carbon atoms are even more preferred. Examples of such hydrocarbon refrigerants 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 butane. These hydrocarbon refrigerants may be used alone or in combination. Furthermore, the hydrocarbon refrigerant may be the aforementioned hydrocarbon alone, or, as described above, may be used as a mixed refrigerant by mixing it with a fluorohydrocarbon refrigerant such as R134a and a refrigerant other than a hydrocarbon refrigerant such as carbon dioxide.

[0093] From the viewpoint of providing a refrigerating oil composition that, when mixed with a refrigerant, improves thermal stability and compatibility with the refrigerant and that can emit strong light when irradiated with ultraviolet light even in a small amount (for example, one drop (0.01 to 0.10 mL)), when component (B) of the refrigerating oil composition of one embodiment of the present invention contains PVE, it is preferably used in combination with a fluorohydrocarbon refrigerant containing a saturated fluorohydrocarbon compound, and is preferably used in combination with one or more refrigerants selected from R23 refrigerant, R32 refrigerant, R152a refrigerant, R143a refrigerant, R143 refrigerant, R134a refrigerant, R134 refrigerant, and R125 refrigerant, more preferably used in combination with a refrigerant containing at least R32 refrigerant, and even more preferably used in combination with an R32 refrigerant or R410A refrigerant.

[0094] From the same viewpoint as above, when component (B) of the refrigerating oil composition of one embodiment of the present invention contains a PAG, it is preferably used by mixing with a fluorohydrocarbon refrigerant containing a saturated fluorohydrocarbon compound or a natural refrigerant, preferably by mixing with one or more refrigerants selected from R23 refrigerant, R32 refrigerant, R152a refrigerant, R143a refrigerant, R143 refrigerant, R134a refrigerant, R134 refrigerant, R125 refrigerant and hydrocarbon refrigerants, and more preferably by mixing with an R134a refrigerant or an R290 refrigerant.

[0095] [Various Properties of Refrigerating Machine Oil Composition] In the refrigerating machine oil composition of one embodiment of the present invention, the water content is preferably 800 ppm by mass or less, more preferably 700 ppm by mass or less, even more preferably 600 ppm by mass or less, and still more preferably 500 ppm by mass or less.

[0096] The acid value of the refrigerator oil composition of one embodiment of the present invention after a thermal stability test carried out based on the method described in the Examples below is preferably 0.30 mgKOH / g or less, more preferably 0.20 mgKOH / g or less, more preferably 0.15 mgKOH / g or less, even more preferably 0.10 mgKOH / g or less, still more preferably 0.08 mgKOH / g or less, and particularly preferably 0.07 mgKOH / g or less.

[0097] The high-temperature side separation temperature of the refrigerator oil composition according to one embodiment of the present invention, measured according to the method described in the Examples below, is preferably 45°C or higher, more preferably 47°C or higher, more preferably 50°C or higher, even more preferably 52°C or higher, even more preferably 54°C or higher, still more preferably 56°C or higher, and particularly preferably 58°C or higher, and the low-temperature side separation temperature is preferably 0°C or lower, more preferably -20°C or lower, even more preferably -30°C or lower, still more preferably -40°C or lower, and particularly preferably -50°C or lower.

[0098] [Refrigerator, Leak Detection Method] The refrigerating machine oil composition of one embodiment of the present invention is filled into a refrigerating machine together with a refrigerant. Here, the refrigerating machine has a refrigeration cycle essentially consisting of a compressor, a condenser, an expansion mechanism (such as an expansion valve), and an evaporator, or a compressor, a condenser, an expansion mechanism, a dryer, and an evaporator. The refrigerating machine oil composition of one embodiment of the present invention can emit strong light when irradiated with ultraviolet light even in small amounts (e.g., one drop (0.01 to 0.10 mL)), making even small leaks easily detectable. Therefore, the refrigerating machine oil composition of one embodiment of the present invention can be suitably used in applications where it circulates through the piping of refrigeration and air conditioning equipment (e.g., piping in showcases, refrigerators, car air conditioners, building multi-air conditioners, etc.). Given the property of the refrigerating machine oil composition of one embodiment of the present invention that allows even small leaks to be easily detected, the larger the refrigeration and air conditioning equipment, the more effectively the property of the present invention can be exhibited, making it more suitable for use.

[0099] Therefore, one aspect of the present invention also provides a leak detection method as set forth in [1] below: [1] A method for detecting leakage of a refrigerating machine mixed composition circulating through the piping of a refrigeration and air conditioning equipment, wherein the refrigerating machine mixed composition is a mixture of the refrigerating machine oil composition according to any one of claims 1 to 7 and one or more refrigerants selected from the group consisting of a fluorohydrocarbon refrigerant, a hydrocarbon (HC) refrigerant that is a natural refrigerant, carbon dioxide, and ammonia, and the leak detection method comprises irradiating the piping with ultraviolet light from the outside, and confirming leakage of the refrigerating machine mixed composition from the piping based on the presence or absence of light emission.

[0100] Next, the present invention will be described in more detail with reference to examples, but the present invention is not limited to these examples. The methods for measuring various physical properties are as follows. (1) Kinematic viscosity and viscosity index: Measured using a glass capillary viscometer in accordance with JIS K2283. (2) Acid value: Measured by indicator photometric titration in accordance with JIS K2501.

[0101] Refrigerating machine oil compositions were prepared by adding and mixing base oils and fluorescent compounds in the amounts and types shown in Tables 1 and 2. Details of the components used in preparing the refrigerating machine oil compositions are as follows:

[0102] <Base oil> "PVE": polyvinyl ether having a structural unit represented by the general formula (b-1) above, one of the terminal moieties being a group represented by the general formula (b-1-i) above, and the other being any of the groups represented by the general formulae (b-1-i) to (b-1-iii) above, kinematic viscosity at 40°C = 64.72 mm ２ / s, 100℃ kinematic viscosity = 8.09mm ２ / s, viscosity index = 90. "PAG": polyoxypropylene glycol dimethyl ether represented by the general formula (b-2-i), 40°C kinematic viscosity = 66.84 mm ２ / s, 100℃ kinematic viscosity = 13.74mm ２ / s, viscosity index=214.

[0103] <Fluorescent Compounds> "Fluorescent compound (1)": A fluorescent compound represented by the following general formula (ai). "Fluorescent compound (2)": A fluorescent compound represented by the following general formula (ii). "Fluorescent compound (3)": A fluorescent compound represented by the following general formula (iii). "Fluorescent compound (4)": A fluorescent compound represented by the following general formula (iv).

[0104] The refrigerator oil compositions prepared in the Examples and Comparative Examples were subjected to the following tests, and the results are shown in Tables 1 and 2.

[0105] (1) Property tests for various refrigerants The following measurements were carried out on refrigerating oil mixed compositions prepared by mixing the refrigerating oil compositions prepared in the Examples and Comparative Examples with any of the following refrigerants in a 1 / 1 (mass ratio). (Refrigerants mixed with the refrigerating oil compositions of Examples 1 and 2 and Comparative Examples 1 to 6) R32 refrigerant: difluoromethane R410A refrigerant: mixture of difluoromethane and pentafluoroethane (Refrigerants mixed with the refrigerating oil compositions of Examples 3 and 4 and Comparative Examples 7 to 9) R134a refrigerant: 1,1,1,2-tetrafluoroethane R290 refrigerant: propane

[0106] (1-1) Thermal Stability Test (Measurement of Acid Value After Test, Evaluation of Presence or Absence of Precipitate) An autoclave vessel (volume: 200 ml) was charged with Fe, Cu, and Al as catalysts, and further charged with a mixture of 30 g of the refrigerating machine oil composition prepared in the Examples and Comparative Examples (20 g for R290 refrigerant) and 30 g of refrigerant (20 g for R290 refrigerant only), 500 ppm by mass of water, and 25 ml of air. The vessel was then held at 175°C for 14 days to conduct a thermal stability test. After the test, the acid value of the contents was measured, and the contents were transferred to a colorless, transparent glass tube and visually observed for the presence or absence of precipitate. The results are shown in Tables 1 and 2. If the acid value after the test was 0.30 mgKOH / g or less and no precipitate was observed, the refrigerating machine oil composition was determined to have high thermal stability.

[0107] (1-2) Measurement of Two-Phase Separation Temperature A two-phase separation temperature measurement tube (internal volume 10 mL) was filled with 0.3 g of the refrigerator oil composition prepared in each of the Examples and Comparative Examples and 2.7 g of a refrigerant, and the tube was placed in a thermostatic bath. The temperature of the thermostatic bath was raised from room temperature (25°C) to 70°C at a rate of 1.0°C / min, and the temperature at which two-phase separation was confirmed was measured as the "high-temperature side separation temperature." Similarly, the temperature of the thermostatic bath was lowered from room temperature (25°C) to -50°C at a rate of 1.0°C / min, and the temperature at which two-phase separation was confirmed was measured as the "low-temperature side separation temperature." These results are shown in Tables 1 and 2. Note that the low-temperature side separation temperature of samples in which two-phase separation was not confirmed even when cooled to -50°C was determined to be "less than -50°C," and is indicated as "<-50" in Tables 1 and 2. Furthermore, if two-layer separation was already confirmed at room temperature (25°C), the composition was recorded as "insoluble" and the test was terminated without conducting the subsequent "luminescence evaluation test." The higher the "high-temperature side separation temperature" and the lower the "low-temperature side separation temperature," the more excellent the compatibility of the refrigerating machine oil composition with the target refrigerant.

[0108] (2) Luminescence Evaluation Test One drop (approximately 0.05 mL) of the refrigerating machine oil composition prepared in each of the Examples and Comparative Examples was dropped onto the outer surface of a copper pipe having a diameter of ½ inch, and ultraviolet light having a central wavelength of 365 nm was irradiated from a position approximately 20 cm away from the surface. Whether luminescence could be visually recognized was confirmed while changing the observation point from the surface, and the luminescence of the refrigerating machine oil composition was evaluated according to the following criteria. These results are shown in Tables 1 and 2. - A: The luminescence was sufficiently visible even from an observation point 3 m or more away from the surface on which the refrigerating machine oil composition was dropped. - B: The luminescence was sufficiently visible from an observation point up to about 3 m from the surface on which the refrigerating machine oil composition was dropped. - C: Although luminescence could be recognized from an observation point about 20 cm away from the surface on which the refrigerating machine oil composition was dropped, the luminescence became more difficult to recognize with increasing distance, and the luminescence was barely visible at an observation point up to about 3 m away. D: A slight luminescence could be observed from an observation point about 20 cm from the surface onto which the refrigerating machine oil composition was dripped, but no luminescence could be visually recognized from an observation point any further away.

[0109]

[0110]

[0111] As can be seen from Tables 1 and 2, the refrigerating machine oil compositions prepared in Examples 1 to 4 exhibited high thermal stability and excellent compatibility even when mixed with various refrigerants, and exhibited strong luminescence even in small amounts. Therefore, when these refrigerating machine oil compositions are mixed with various refrigerants and used as refrigerating machine oils circulating through the piping of large refrigeration and air conditioning equipment, such as multi-air conditioners for buildings, even a small leak of refrigerating machine oil from the piping emits strong light upon exposure to ultraviolet light, making it easy to detect refrigerating machine oil leaks. On the other hand, the refrigerating machine oil compositions prepared in Comparative Examples 1 to 3 and 7 to 9 exhibited weak luminescence, making them unlikely to be used as refrigerating machine oils circulating through the piping of large refrigeration and air conditioning equipment, such as multi-air conditioners for buildings. Furthermore, the refrigerating machine oil compositions prepared in Comparative Examples 4 to 6 exhibited problems with thermal stability and compatibility with refrigerants, and therefore were discontinued without conducting a luminescence evaluation test.

Claims

1. The following general formula (a-1): (In the above formula, R １ and R ２ and each independently represent an alkyl group having 2 or more carbon atoms or an alkenyl group having 2 or more carbon atoms, and a base oil (B), wherein the content of component (A) is 0.60 mass% or more based on the total amount of the refrigerating oil composition.

2. The refrigerator oil composition according to claim 1, wherein the content of component (A) is 1.00 mass % or more based on the total amount of the refrigerator oil composition.

3. R ​​in the general formula (a-1) １ and R ２ The refrigerator oil composition according to claim 1 or 2, wherein is an ethyl group.

4. The refrigerator oil composition according to any one of claims 1 to 3, wherein component (B) comprises one or more selected from polyvinyl ethers (PVE), polyalkylene glycols (PAG), polyol esters (POE), and mineral oil.

5. A refrigerator oil composition according to any one of claims 1 to 4, wherein component (B) comprises at least one member selected from the group consisting of polyvinyl ethers (PVE) and polyalkylene glycols (PAG).

6. The refrigerating machine oil composition according to any one of claims 1 to 5, which is used in combination with one or more refrigerants selected from the group consisting of fluorohydrocarbon refrigerants, hydrocarbon (HC) refrigerants which are natural refrigerants, carbon dioxide, and ammonia.

7. The refrigerating machine oil composition according to any one of claims 1 to 5, which is mixed with one or more refrigerants selected from the group consisting of fluorohydrocarbon refrigerants, hydrocarbon (HC) refrigerants which are natural refrigerants, carbon dioxide, and ammonia, and is circulated through the piping of a refrigeration and air conditioning equipment as a mixed composition for a refrigerating machine.

8. A mixed composition for a refrigerator, comprising the refrigerator oil composition according to any one of claims 1 to 7, and one or more refrigerants selected from the group consisting of fluorohydrocarbon refrigerants, hydrocarbon (HC) refrigerants which are natural refrigerants, carbon dioxide, and ammonia.

9. A method for detecting leakage of a refrigerating machine mixed composition circulating through the piping of a refrigeration and air conditioning equipment, wherein the refrigerating machine mixed composition is a mixture of the refrigerating machine oil composition according to any one of claims 1 to 7 and one or more refrigerants selected from the group consisting of fluorohydrocarbon refrigerants, hydrocarbon (HC) refrigerants which are natural refrigerants, carbon dioxide, and ammonia, and the leakage of the refrigerating machine mixed composition from the piping is confirmed by irradiating the piping with ultraviolet light from the outside and determining whether or not light is emitted.

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