Refrigerating-machine oil composition and mixture composition for refrigerating machine

Abstract

Provided is a refrigerating-machine oil composition comprising a base oil (A), an epoxy compound (B) represented by general formula (b-1), and an unsaturated compound (C) having at least one double bond, wherein the content of the component (B) exceeds 1.0 mass% with respect to the total amount of the refrigerating-machine oil composition. In formula (b-1), R1 is a C1-C24 alkyl group, a C2-C24 alkenyl group, or a cycloalkyl group which is optionally substituted with a C1-C6 alkyl group and in which the number of ring-forming carbon atoms is 3-12, p is an integer of 0-4, q is 0 or 1, and r is an integer of 0-10.

Description

Refrigerating machine oil composition and mixed composition for refrigerators

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

[0002] Refrigeration systems, such as compression-type refrigerators, generally include at least a compressor, a condenser, an expansion mechanism (e.g., an expansion valve), and an evaporator, and have a structure in which a refrigeration mixture circulates within a sealed system.

[0003] In refrigerators such as compression refrigerators, fluorinated hydrocarbon compounds, which have a lower environmental impact, are increasingly being used as refrigerants, replacing hydrochlorofluorocarbons (HCFCs), which were previously widely used. Examples of fluorinated hydrocarbon compounds include saturated fluorinated hydrocarbon 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).

[0004] Furthermore, the use of unsaturated fluorinated hydrocarbon compounds (Hydro-Fluoro-Olefin; hereinafter also referred to as "HFO"), which have a lower global warming potential (GWP) than HFCs, is also being considered. As HFOs, propene-based HFOs such as 1,3,3,3-tetrafluoropropene (R1234ze), 2,3,3,3-tetrafluoropropene (R1234yf), and 1,2,3,3-tetrafluoropropene (R1234ye) have been extensively studied. Refrigeration oil compositions suitable for such HFO refrigerants have also been investigated; for example, Patent Document 1 describes a refrigeration oil composition suitable for 2,3,3,3-tetrafluoropropene (R1234yf), etc.

[0005] International Publication No. 2015 / 050137

[0006] Incidentally, when refrigerant oil compositions are used in combination with refrigerants, the acid value may increase, and there is a need for improved stability. Therefore, one aspect of the present invention aims to provide a refrigerant oil composition that can suppress the increase in acid value and exhibit excellent stability even when used in combination with a refrigerant.

[0007] One aspect of the present invention provides a refrigeration oil composition containing a base oil, a specific amount of an epoxy compound having a specific structure, and an unsaturated compound having at least one double bond. Specifically, one aspect of the present invention provides the following invention: [1] Base oil (A), the following general formula (b-1) (In the above formula, R １A refrigerant oil composition comprising an epoxy compound (B) represented by (1 to 24 C1), an alkenyl group having 2 to 24 C1, or a ring-forming cycloalkyl group having 3 to 12 C1 which may be substituted with an alkyl group having 1 to 6 C1. p is an integer from 0 to 4, q is 0 or 1, and r is an integer from 0 to 10. (2) A refrigerant oil composition comprising an epoxy compound (B) represented by (1) and an unsaturated compound (C) having at least one double bond, wherein the content of component (B) is greater than 1.0% by mass on a basis of the total amount of the refrigerant oil composition. (2) The refrigerant oil composition according to [1] above, wherein the content of component (B) is greater than 1.0% by mass and 5.0% by mass or less on a basis of the total amount of the refrigerant oil composition. (3) The refrigerant oil composition according to [1] or [2] above, wherein the content of component (C) is greater than 0.5% by mass and 10% by mass or less on a basis of the total amount of the refrigerant oil composition. [4] The refrigeration oil composition according to any one of [1] to [3] above, wherein the mass ratio of component (B) to component (C) [(B) / (C)] is 0.10 or more and 5.00 or less. [5] The refrigeration oil composition according to any one of [1] to [4] above, wherein component (B) contains a glycidyl ether (B1) having an alkyl group having 1 to 24 carbon atoms. [6] The refrigeration oil composition according to any one of [1] to [5] above, wherein component (C) is one or more selected from a terpene compound (C1) having at least one constituent unit derived from isoprene, a vinyl compound (C2) having at least one vinyl group, and an unsaturated alicyclic compound (C3) having a cycloolefin structure. [7] The refrigeration oil composition according to any one of [1] to [6] above, wherein component (C) has an epoxy structure. [8] The refrigeration oil composition according to any one of [1] to [7] above, wherein component (C) comprises one or more selected from pinene, limonene oxide, terpinene, bisabolene, cycloalkene having 3 to 12 ring-forming carbon atoms and having an epoxy structure, farnesene, and cycloalkane having 3 to 12 ring-forming carbon atoms and having at least one vinyl group. [9] The refrigeration oil composition according to any one of [1] to [8] above, wherein component (A) comprises one or more selected from polyvinyl ethers (PVE), polyol esters (POE), and polyoxyalkylene glycols (PAG).

[10] A mixed composition for a refrigerator containing the refrigerant oil composition and a refrigerant as described in any one of the above items [1] to [9].

[11] The mixed composition for a refrigerator according to

[10] , wherein the refrigerant contains an unsaturated fluorinated hydrocarbon compound.

[0008] A refrigeration oil composition according to one aspect of the present invention can suppress an increase in acid value and exhibit excellent stability even when mixed with a refrigerant.

[0009] The numerical ranges described herein can be any combination of upper and lower limits. For example, if the numerical range is described as "preferably 30 to 100, more preferably 40 to 80," the ranges of "30 to 80" and "40 to 100" are also included in the numerical range described herein. Similarly, if the numerical range is described as "preferably 30 or more, more preferably 40 or more, and also preferably 100 or less, more preferably 80 or less," the ranges of "30 to 80" and "40 to 100" are also included in the numerical range described herein. In addition, for example, if the numerical range described herein is described as "60 to 100," it means the range is "60 or more (60 or greater than 60), and 100 or less (100 or less than 100)." Furthermore, in the provisions for upper and lower limits described herein, the numerical range from the lower limit to the upper limit can be defined by appropriately selecting and combining the options from each set of choices.

[0010] [Composition of Refrigerant Oil Composition] A refrigerant oil composition according to one aspect of the present invention contains a base oil (A) (hereinafter also referred to as "component (A)"), an epoxy compound represented by general formula (b-1) (B) (hereinafter also referred to as "component (B)"), and an unsaturated compound (C) having at least one double bond (C) (hereinafter also referred to as "component (C)").

[0011] For example, HFO refrigerants have low thermal stability at high temperatures and are prone to generating acidic substances that cause an increase in acid value. The presence of these acidic substances leads to an increase in acid value and can cause malfunctions in refrigeration systems. In response to this problem, the inventors have found that by creating a refrigeration oil composition containing a predetermined amount of component (B) along with component (C), the increase in acid value can be effectively suppressed when used in combination with a refrigerant, compared to a refrigeration oil composition containing only component (C). One embodiment of the present invention is based on this finding and contains a predetermined amount of component (B) along with component (C), and exhibits the effect of suppressing the increase in acid value and exhibiting excellent stability even when mixed with a refrigerant.

[0012] In a refrigerant oil composition according to one aspect of the present invention, from the viewpoint of providing a refrigerant oil composition with excellent stability that can suppress an increase in acid value when mixed with a refrigerant, the mass ratio of component (B) to component (C) [(B) / (C)] is preferably 0.10 or more, 0.15 or more, 0.20 or more, 0.25 or more, 0.30 or more, 0.35 or more, 0.40 or more, 0.45 or more, 0.50 or more, 0.55 or more, 0.60 or more, or 0.65 or more, and also preferably 5.00 or less, 4.50 or less, 4.00 or less, 3.50 or less, 3.00 or less, 2.80 or less, 2.60 or less, 2.40 or less, 2.20 or less, 2.00 or less, 1.80 or less, or 1.60 or less.

[0013] A refrigerant oil composition according to one aspect of the present invention may further contain other additives besides components (A) to (C). In a refrigerant oil composition according to one aspect of the present invention, the total content of components (A) to (C) 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, 93% by mass or more, 95% by mass or more, or 97% by mass or more, based on the total amount (100% by mass) of the refrigerant oil composition, and may also be 100% by mass or less, 99.9% by mass or less, or 99.0% by mass or less.

[0014] The following describes in detail each component contained in the refrigeration oil composition of this embodiment.

[0015] <Component (A): Base Oil> A refrigeration oil composition according to one aspect of the present invention contains a base oil as component (A). Component (A) used in one aspect of the present invention can be, for example, one or more selected from the group consisting of synthetic oils and mineral oils. However, from the viewpoint of providing a refrigeration oil composition with improved solubility and stability when mixed with a refrigerant, it is preferable to include a base oil (A1) consisting of one or more selected from the group consisting of polyvinyl ethers (hereinafter also referred to as "PVE"), polyalkylene glycols (hereinafter also referred to as "PAG"), and polyol esters (hereinafter also referred to as "POE"). It is more preferable to include a base oil (A2) consisting of one or more selected from the group consisting of PVE and PAG, and even more preferable to include a base oil (A3) consisting of PVE. PVE, PAG, POE, and mineral oil will be described in detail below.

[0016] (Polyvinyl ethers (PVE)) The PVE used in one aspect of the present invention may be any polymer having one or more constituent units derived from vinyl ether. When component (A) contains PVE, one type of PVE may be used alone, or two or more types may be used in combination.

[0017] PVE is preferably a polymer (A-1) having one or more constituent units represented by the following general formula (A-1).

[0018]

[0019] In formula (A-1), R １ａ , R ２ａ and R ３ａ Each of these independently represents a hydrogen atom or a hydrocarbon group having 1 to 8 carbon atoms. ４ａ This represents a divalent hydrocarbon group having 2 to 10 carbon atoms. ５ａ represents a hydrocarbon group having 1 to 10 carbon atoms. r represents OR ４ａ The number of repeating units is an integer from 0 to 10, but from the viewpoint of providing a refrigerant oil composition with improved solubility and stability when mixed with a refrigerant, it is preferably an integer from 0 to 5, more preferably an integer from 0 to 3, and even more preferably 0. Note that OR is present in the constituent unit represented by the above general formula (A-1) ４ａ If multiple ORs exist,４ａ may be the same or different.

[0020] R １ａ 、R ２ａ and R ３ａ Examples of the hydrocarbon group having 1 to 8 carbon atoms represented by R, R, and R include alkyl groups such as methyl group, ethyl group, n-propyl group, isopropyl group, n-butyl group, isobutyl group, sec-butyl group, tert-butyl group, various pentyl groups, various hexyl groups, various heptyl groups, and various octyl groups; cycloalkyl groups such as cyclopentyl group, cyclohexyl group, various methylcyclohexyl groups, various ethylcyclohexyl groups, and various dimethylcyclohexyl groups; aryl groups such as phenyl group, various methylphenyl groups, various ethylphenyl groups, and various dimethylphenyl groups; arylalkyl groups such as benzyl group, various phenylethyl groups, and various methylbenzyl groups; etc. Here, "various" means a hydrocarbon group that is "linear, branched, or cyclic". For example, "various butyl groups" means various butyl groups such as "n-butyl group, sec-butyl group, isobutyl group, tert-butyl group, cyclobutyl group". In addition, for a group having a cyclic structure, it means including positional isomers such as ortho-isomer, meta-isomer, and para-isomer, and the same applies hereinafter.

[0021] R １ａ 、R ２ａ and R ３ａ From the viewpoint of obtaining a refrigerant oil composition with improved solubility and stability when mixed with the refrigerant, the number of carbon atoms of the hydrocarbon group represented by R, R, and R is preferably 1 to 6, more preferably 1 to 3. R, R, and R are each independently preferably a hydrogen atom or an alkyl group having 1 to 8 carbon atoms, and more preferably a hydrogen atom or an alkyl group having 1 to 3 carbon atoms, from the viewpoint of obtaining a refrigerant oil composition with improved solubility and stability when mixed with the refrigerant. １ａ 、R ２ａ and R ３ａ are each independently preferably a hydrogen atom or an alkyl group having 1 to 8 carbon atoms, and more preferably a hydrogen atom or an alkyl group having 1 to 3 carbon atoms, from the viewpoint of obtaining a refrigerant oil composition with improved solubility and stability when mixed with the refrigerant.

[0022] R ４ａExamples of divalent hydrocarbon groups having 2 to 10 carbon atoms represented by include: divalent aliphatic groups such as ethylene, 1,2-propylene, 1,3-propylene, various butylene, various pentylene, various hexylene, various heptylene, various octylene, various nonylene, and various desilene; divalent alicyclic groups such as cyclohexane, methylcyclohexane, ethylcyclohexane, dimethylcyclohexane, and propylcyclohexane; divalent aromatic groups such as various phenylene, various methylphenylene, various ethylphenylene, various dimethylphenylene, and various naphthylene; divalent alkyl aromatic groups having monovalent bonding sites on both the alkyl and aromatic portions of alkyl aromatic hydrocarbons such as toluene, xylene, and ethylbenzene; and divalent alkyl aromatic groups having bonding sites on the alkyl portion of polyalkyl aromatic hydrocarbons such as xylene and diethylbenzene. ４ａ The number of carbon atoms in the hydrocarbon group represented by is preferably 2 to 6, more preferably 2 to 4, from the viewpoint of providing a refrigerant oil composition with improved solubility and stability when mixed with a refrigerant. ４ａ From the viewpoint of providing a refrigerant oil composition with improved solubility and stability when mixed with a refrigerant, a divalent aliphatic group having 2 to 10 carbon atoms is preferred, and a divalent aliphatic group having 2 to 4 carbon atoms is more preferred.

[0023] R ５ａExamples of hydrocarbon groups having 1 to 10 carbon atoms represented include alkyl groups such as methyl group, ethyl group, n-propyl group, isopropyl group, n-butyl group, isobutyl group, sec-butyl group, tert-butyl group, various pentyl groups, various hexyl groups, various heptyl groups, various octyl groups, various nonyl groups, and various decyl groups; cycloalkyl groups such as cyclopentyl group, cyclohexyl group, various methylcyclohexyl groups, various ethylcyclohexyl groups, various propylcyclohexyl groups, and various dimethylcyclohexyl groups; aryl groups such as phenyl group, various methylphenyl group, various ethylphenyl group, various dimethylphenyl group, various propylphenyl group, various trimethylphenyl group, various butylphenyl group, and various naphthyl group; and arylalkyl groups such as benzyl group, various phenylethyl group, various methylbenzyl group, various phenylpropyl group, and various phenylbutyl group. ５ａ The number of carbon atoms in the hydrocarbon group represented by is preferably 1 to 8, more preferably 1 to 6, from the viewpoint of obtaining a refrigerant oil composition with improved solubility and stability when mixed with a refrigerant. ５ａ From the viewpoint of providing a refrigerant oil composition with improved solubility and stability when mixed with a refrigerant, alkyl groups having 1 to 6 carbon atoms are preferred, and alkyl groups having 1 to 4 carbon atoms are more preferred.

[0024] The number of units (degree of polymerization) of the constituent units represented by the above general formula (A-1) is appropriately selected according to the kinematic viscosity required for the base oil (A). Furthermore, the polymer having the constituent units represented by the above general formula (A-1) may be a homopolymer having only one type of constituent unit, or a copolymer having two or more types of constituent units. When the polymer is a copolymer, there are no particular restrictions on the form of copolymerization, and it may be a block copolymer, a random copolymer, or a graft copolymer. In addition, PVE may contain a polyalkylene glycol structure in its structure, but from the viewpoint of providing a refrigeration oil composition with improved solubility and stability when mixed with a refrigerant, it is preferable that it does not contain a polyalkylene glycol structure.

[0025] The terminal portion of polymer (A-1) may be fitted with a monovalent group derived from saturated hydrocarbons, ethers, alcohols, ketones, amides, nitriles, etc. Among these, from the viewpoint of obtaining a refrigerant oil composition with improved solubility and stability when mixed with a refrigerant, it is preferable that one terminal portion of polymer (A-1) is a group represented by the following general formula (A-1-i).

[0026]

[0027] In formula (A-1-i), * indicates the bonding position with the carbon atom in the constituent unit represented by the general formula (A-1) above. In formula (A-1-i), R ６ａ , R ７ａ and R ８ａ Each of these independently represents a hydrogen atom or a hydrocarbon group having 1 to 8 carbon atoms. From the viewpoint of providing a refrigerant oil composition with improved solubility and stability when mixed with a refrigerant, a hydrogen atom or a hydrocarbon group having 1 to 6 carbon atoms is preferred, and a hydrogen atom or an alkyl group having 1 to 3 carbon atoms is more preferred. ６ａ , R ７ａ and R ８ａ As a hydrocarbon group having 1 to 8 carbon atoms represented by the above general formula (A-1), R １ａ , R ２ａ and R ３ａ The same examples listed as hydrocarbon groups with 1 to 8 carbon atoms represented by can be cited.

[0028] In the above formula (A-1-i), R ９ａ In the above formula (A-1-i), r1 is OR ９ａ The number of repeating units is an integer from 0 to 10, and from the viewpoint of providing a refrigerant oil composition with improved solubility and stability when mixed with a refrigerant, it is preferably an integer from 0 to 5, more preferably an integer from 0 to 3, and even more preferably 0. Note that OR is included in the constituent unit represented by the above general formula (A-1-i) ９ａ If multiple ORs exist, ９ａThey may be the same or they may be different. ９ａ As a divalent hydrocarbon group having 2 to 10 carbon atoms represented by the above general formula (A-1), R ４ａ The same divalent hydrocarbon groups with 2 to 10 carbon atoms represented by the formula are listed below.

[0029] In formula (A-1-i), R １０ａ R represents a hydrocarbon group having 1 to 10 carbon atoms, and from the viewpoint of providing a refrigerant oil composition with improved solubility and stability when mixed with a refrigerant, a hydrocarbon group having 1 to 8 carbon atoms is preferred, and an alkyl group having 1 to 8 carbon atoms is more preferred. １０ａ As for the case where r1 in the above general formula (A-1-i) is 0, an alkyl group having 1 to 6 carbon atoms is preferred from the viewpoint of providing a refrigerant oil composition with improved solubility and stability when mixed with a refrigerant, and when r1 is 1 or more, an alkyl group having 1 to 4 carbon atoms is preferred. １０ａ As a hydrocarbon group having 1 to 10 carbon atoms represented by the above general formula (A-1), R ５ａ Examples include the same hydrocarbon groups with 1 to 10 carbon atoms as listed above.

[0030] Furthermore, from the viewpoint of providing a refrigerant oil composition with improved solubility and stability when mixed with a refrigerant, it is preferable that, when one terminal portion of polymer (A-1) is a group represented by the above general formula (A-1-i), the other terminal portion is one of the following: a group represented by the above general formula (A-1-i), a group represented by the following general formula (A-1-ii), a group represented by the following general formula (A-1-iii), or a group having an olefinic unsaturated bond.

[0031]

[0032] In equations (A-1-ii) and (A-1-iii), R ６ａ , R ７ａ , R ８ａ , R ９ａ , R １０ａ And r1 are the same as those specified in the above general formula (A-1-i). Also, in formula (A-1-ii), R １１ａ , R １２ａand r2 are R in the above general formula (A-1-i), respectively. ９ａ , R １０ａ And the same as the provisions of r1.

[0033] In one embodiment of the present invention, from the viewpoint of providing a refrigerant oil composition with improved solubility and stability when mixed with a refrigerant, the PVE having a constituent unit represented by general formula (A-1) is R １ａ , R ２ａ , and R ３ａ Both are hydrogen atoms, r is 0, R ５ａ Polyethyl vinyl ether, in which the group is an ethyl group, is preferred. Furthermore, from the viewpoint of providing a refrigerant oil composition with improved solubility and stability when mixed with a refrigerant, PVE having a constituent unit represented by general formula (A-1) is preferred. １ａ , R ２ａ , and R ３ａ Both are hydrogen atoms, r is 0, R ５ａ Polyethyl vinyl ether, in which the ethyl group is R １ａ , R ２ａ , and R ３ａ Both are hydrogen atoms, r is 0, R ５ａ It is preferable that the copolymer is with polyisobutyl vinyl ether, where isobutyl group. In this case, the content ratio of constituent units of ethyl vinyl ether to constituent units of isobutyl vinyl ether [(constituent units of ethyl vinyl ether) / (constituent units of isobutyl vinyl ether)] is, from the above viewpoint, preferably 50 / 50 to 99 / 1 in molar ratio, more preferably 70 / 30 to 99 / 1, even more preferably 75 / 25 to 95 / 5, and even more preferably 80 / 20 to 90 / 10.

[0034] (Polyalkylene glycols (PAGs)) In one aspect of the present invention, the PAG used is preferably a polymer (A-2) represented by the following general formula (A-2). １３ａ -[(OR １４ａ ) ｍ -OR １５ａ ] ｎ (A-2) If component (A) contains PAG, PAG may be used alone or in combination of two or more types.

[0035] In the above general formula (A-2), R １３ａ R 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-forming atoms. １４ａ This represents an alkylene group having 2 to 4 carbon atoms, R １５ａ This 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-forming atoms. Examples of substituents that the heterocyclic group may have include alkyl groups having 1 to 10 carbon atoms; cycloalkyl groups having 3 to 10 ring-forming carbon atoms; aryl groups having 6 to 18 ring-forming carbon atoms; halogen atoms (fluorine, chlorine, bromine, or iodine); cyano groups; nitro groups; hydroxyl groups; and amino groups. Among these, the substituent is preferably an alkyl group having 1 to 6 carbon atoms, a cycloalkyl group having 3 to 8 ring-forming carbon atoms, or an aryl group having 6 to 12 ring-forming carbon atoms, and more preferably an alkyl group having 1 to 3 carbon atoms or a cycloalkyl group having 5 to 6 ring-forming carbon atoms. These substituents may be further substituted with any of the substituents mentioned above.

[0036] n is an integer from 1 to 6, and from the viewpoint of obtaining a refrigerant oil composition with improved solubility and stability when mixed with a refrigerant, it is preferably an integer from 1 to 3, more preferably 1. Note that n is R in the above general formula (A-2) １３ａ It is determined according to the number of bonding sites. For example, R １３ａ If is an alkyl group or an acyl group, then n becomes 1, R １３ａ If is a hydrocarbon group or a heterocyclic group and the valency of the group is 2, 3, 4, 5, or 6, then n will be 2, 3, 4, 5, or 6, respectively. m is OR １４ａ The number of repeating units is 1 or more, preferably a number such that m × n is 6 to 80. The value of m is such that the kinematic viscosity of the base oil (A) at 100°C is 2 to 50 mm². ２ The value is set appropriately so as to fall within the range of / s, and there are no particular restrictions as long as the kinematic viscosity is adjusted to fall within a predetermined range.１４ａ These may be the same or different from each other. Also, if n is 2 or more, there may be multiple R in one molecule. １５ａ They may be the same as or different from each other.

[0037] R １３ａ and R １５ａ Examples of the monovalent hydrocarbon groups represented above include alkyl groups such as methyl group, ethyl group, n-propyl group, isopropyl group, n-butyl group, isobutyl group, sec-butyl group, tert-butyl group, various pentyl groups, various hexyl groups, various heptyl groups, various octyl groups, various nonyl groups, and various decyl groups; cycloalkyl groups such as cyclopentyl group, cyclohexyl group, various methylcyclohexyl groups, various ethylcyclohexyl groups, various propylcyclohexyl groups, and various dimethylcyclohexyl groups; aryl groups such as phenyl group, 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 group, various phenylethyl groups, various methylbenzyl groups, various phenylpropyl groups, and various phenylbutyl groups. Note that the alkyl groups may be linear or branched. １３ａ and R １５ａ The number of carbon atoms in the monovalent hydrocarbon group represented by is preferably 1 to 10, more preferably 1 to 6, and even more preferably 1 to 3, from the viewpoint of providing a refrigerant oil composition with improved solubility and stability when mixed with a refrigerant.

[0038] R １３ａ and R １５ａ The hydrocarbon group portion of the above-mentioned acyl group having 2 to 10 carbon atoms may be linear, branched, or cyclic. The alkyl group portion is as described above R １３ａ and R １５ａ Examples of hydrocarbon groups represented by include those with 1 to 9 carbon atoms. １３ａ and R １５ａ The number of carbon atoms in the acyl group represented by is preferably 2 to 8, more preferably 2 to 6, from the viewpoint of providing a refrigerant oil composition with improved solubility and stability when mixed with a refrigerant.

[0039] R １３ａ Examples of the above divalent to hexavalent hydrocarbon group represented by R １３ａ include residues obtained by further removing 1 to 5 hydrogen atoms from the monovalent hydrocarbon group represented by R １３ａ residues obtained by removing hydroxyl groups from polyhydric alcohols such as trimethylolpropane, glycerin, pentaerythritol, sorbitol, 1,2,3 - trihydroxycyclohexane, 1,3,5 - trihydroxycyclohexane, etc. The carbon number of the divalent to hexavalent acyl group represented by R

[0040] R １３ａ and R １５ａ As the above heterocyclic group represented by R

[0041] are 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 obtained by removing 1 to 6 hydrogen atoms from oxygen atom - containing saturated heterocycles such as ethylene oxide, 1,3 - propylene oxide, tetrahydrofuran, tetrahydropyran, hexamethylene oxide; oxygen atom - containing unsaturated heterocycles such as acetylene oxide, furan, pyran, oxycycloheptatriene, isobenzofuran, isochromene. Examples of the sulfur atom - containing heterocyclic group include residues obtained by removing 1 to 6 hydrogen atoms from sulfur atom - containing saturated heterocycles such as ethylene sulfide, trimethylene sulfide, tetrahydrothiophene, tetrahydrothiopyran, hexamethylene sulfide; sulfur atom - containing unsaturated heterocycles such as acetylene sulfide, thiophene, thiapyran, thiotripyridine. R １３ａ and R １５ａThe above-mentioned complex cyclic group represented by [formula] may have a substituent, and the substituent may be bonded to the oxygen atom in the above general formula (A-2). The substituent is as described above. From the viewpoint of obtaining a refrigerant oil composition with improved solubility and stability when mixed with a refrigerant, an alkyl group having 1 to 6 carbon atoms is preferable, and an alkyl group having 1 to 3 carbon atoms is more preferable. The number of ring-forming atoms of the above complex cyclic group is preferably 3 to 10, more preferably 3 to 6, from the viewpoint of obtaining a refrigerant oil composition with improved solubility and stability when mixed with a refrigerant.

[0042] R １４ａ Examples of the above-mentioned alkylene group represented by [formula] include alkylene groups having 2 carbon atoms such as a dimethylene group (—CH ２ CH ２ —), an ethylene group (—CH(CH ３ ))—); alkylene groups having 3 carbon atoms such as a trimethylene group (—CH ２ CH ２ [ CH ２ —), a propylene group (—CH(CH ３ ))CH ２ —), a propylidene group (—CHCH ２ CH ３ —), an isopropylidene group (—C(CH ３ )) ２ —); alkylene groups having 4 carbon atoms such as a tetramethylene group (—CH[[ID=3%]] ２ CH ２ CH ２ CH ２ —), a 1-methyltrimethylene group (—CH(CH ３ ))CH ２ CH ２ —), a 2-methyltrimethylene group (—CH ２ CH(CH ３ ))CH ２ —), a butylene group (—C(CH ３ )) ２ CH ２ —). Among these, as R １４ａ , a propylene group (—CH(CH ３ ))CH ２ —) is preferable.

[0043] Furthermore, in the polymer (A-2) represented by the above general formula (A-2), the oxypropylene unit (-OCH(CH) ３ )CH ２ The content of -) is determined from the viewpoint of creating a refrigerant oil composition with improved solubility and stability when mixed with the refrigerant, in the polymer (A-2) oxyalkylene (OR １４ａ Based on the total amount (100 mol%), the amount is preferably 50 mol% or more, more preferably 65 mol% or more, and even more preferably 80 mol% or more.

[0044] From the viewpoint of providing a refrigerant oil composition with improved solubility and stability when mixed with a refrigerant, it is preferable to use one or more polymers (A-2) represented by the above general formula (A-2) selected from the group consisting of polyoxypropylene glycol dimethyl ether represented by the following general formula (A-2-i), polyoxyethylene polyoxypropylene glycol dimethyl ether represented by the following general formula (A-2-ii), polyoxypropylene glycol monobutyl ether represented by the following general formula (A-2-iii), and polyoxypropylene glycol diacetate.

[0045] (In formula (A-2-i), m1 represents a number of 1 or more, preferably a number between 6 and 80.)

[0046] (In formula (A-2-ii), m2 and m3 each independently represent a number of 1 or more, preferably a number such that the value of m2 + m3 is between 6 and 80.)

[0047] (In formula (A-2-iii), m4 represents a number of 1 or more, preferably a number between 6 and 80.)

[0048] Furthermore, m1 in the above general formula (A-2-i), m2 and m3 in the above general formula (A-2-ii), and m4 in the above general formula (A-2-iii) may be appropriately selected according to the required kinematic viscosity of the base oil (A).

[0049] (Polyol esters (POE)) Examples of POE used in one aspect of the present invention include esters of a diol or polyol and a fatty acid. When POE is included in component (A), one type of POE may be used alone, or two or more types may be used in combination. From the viewpoint of providing a refrigerant oil composition with improved solubility and stability when mixed with a refrigerant, the POE is preferably an ester of a diol or polyol having 3 to 20 hydroxyl groups and a fatty acid having 3 to 20 carbon atoms.

[0050] 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.

[0051] Examples of polyols include trimethylolethane, trimethylolpropane, trimethylolbutane, di(trimethylolpropane), tri(trimethylolpropane), pentaerythritol, di(pentaerythritol), tri(pentaerythritol), glycerin, polyglycerin (2-20 mers of glycerin), 1,3,5-pentanetriol, sorbitol, sorbitan, sorbitol-glycerin condensate, adonitol, arabitol, xylitol, mannitol, and other polyhydric alcohols; sugars such as xylose, arabinose, ribose, rhamnose, glucose, fructose, galactose, mannose, sorbose, cellobiose, maltose, isomaltose, trehalose, sucrose, raffinose, gentianose, and meridinetose; and their partial ethers, methyl glucosides (glycosides), etc. Among these, from the viewpoint of providing a refrigerant oil composition with improved solubility and stability when mixed with a refrigerant, hindered alcohols such as neopentyl glycol, trimethylolethane, trimethylolpropane, trimethylolbutane, di(trimethylolpropane), tri(trimethylolpropane), pentaerythritol, di(pentaerythritol), and tri(pentaerythritol) are preferred. A hindered alcohol refers to an alcohol having a quaternary carbon atom bonded to four carbon atoms.

[0052] From the viewpoint of lubrication performance, the number of carbon atoms in 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 compatibility with refrigerants, it is preferably 20 or less, more preferably 16 or less, even more preferably 12 or less, and even more preferably 10 or less. The number of carbon atoms in the fatty acid mentioned above includes the carbon atoms of the carboxyl group (-COOH) that the fatty acid has. The fatty acid may be either a linear fatty acid or a branched fatty acid, but from the viewpoint of lubrication performance, linear fatty acids are preferred, and from the viewpoint of hydrolysis stability, branched fatty acids are preferred. Furthermore, the fatty acid may be either a saturated fatty acid or an unsaturated fatty acid.

[0053] Examples of fatty acids include straight-chain 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, eicosanic acid, and oleic acid, or so-called neoacids in which the α-carbon atoms are 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, 3,5,5-trimethylhexanoic acid, etc. are preferred.

[0054] The polyol ester (POE) may be a partial ester in which some of the hydroxyl groups of the polyol remain unesterified, or it may be a complete ester in which all hydroxyl groups are esterified. Furthermore, the POE may be a mixture of a partial ester and a complete ester, but a complete ester is preferred.

[0055] 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 as POEs, with esters of neopentyl glycol, trimethylolethane, trimethylolpropane, trimethylolbutane, and pentaerythritol being more preferred, and pentaerythritol esters being even more preferred from the viewpoint of particularly excellent compatibility with refrigerants and hydrolysis stability.

[0056] Specific examples of preferred POEs include: diesters of neopentyl glycol with one or more fatty acids selected from the group consisting of 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 with one or more fatty acids selected from the group consisting of 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 trimethylolpropane with isobutyric acid, valeric acid, caproic acid, enanthic acid, caprylic acid, pelargonic acid, capric acid, oleic acid, isopentanoic acid, 2-methylhexanoic acid. Examples include triesters of trimethylolbutane with one or more fatty acids selected from the group consisting of 2-ethylpentanoic acid, 2-ethylpentanoic acid, and 3,5,5-trimethylhexanoic acid; triesters of trimethylolbutane with one or more fatty acids selected from the group consisting of 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 with one or more fatty acids selected from the group consisting of 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.

[0057] Furthermore, the esters of two or more fatty acids may also 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 viewpoint of improving low-temperature characteristics and compatibility with refrigerants.

[0058] (Preferred embodiment of component (A)) In one embodiment of the present invention, the main component of component (A) is preferably the base oil (A1), more preferably the base oil (A2), and even more preferably the base oil (A3), from the viewpoint of providing a refrigerant oil composition with improved solubility and stability when mixed with a refrigerant. In this specification, "main component" means the component with the highest content. In one aspect of the present invention, the content of base oil (A1), base oil (A2), or base oil (A3) in component (A) is preferably 50-100% by mass, 60-100% by mass, 70-100% by mass, 80-100% by mass, 85-100% by mass, 90-100% by mass, 95-100% by mass, 97-100% by mass, 99-100% by mass, or 100% by mass, based on the total amount (100% by mass) of base oil (A), from the viewpoint of providing a refrigerant oil composition with improved solubility and stability when mixed with a refrigerant.

[0059] (Other base oils) Component (A) used in the present invention may contain base oils that do not fall under PVE, PAG, and POE. Examples of other base oils include mineral oil or other synthetic oils other than PVE, PAG, and POE. Other base oils may be used alone or in combination of two or more.

[0060] Examples of mineral oils include oils obtained by distilling paraffinic, intermediate-based, or naphthenic crude oil at atmospheric pressure, or by performing vacuum distillation on a lubricating oil fraction obtained by atmospheric residual oil obtained from atmospheric distillation of crude oil, and then refining that fraction by performing one or more treatments such as solvent delamination, solvent extraction, hydrocracking, solvent dewaxing, catalytic dewaxing, and hydrorefining; and oils produced by isomerizing mineral oil-based waxes.

[0061] Synthetic oils other than PVE, PAG, and POE include, for example, synthetic oils such as polyesters, polycarbonates, hydrides of α-olefin oligomers, alicyclic hydrocarbon compounds, alkylated aromatic hydrocarbon compounds, poly(oxy)alkylene glycol or copolymers of its monoether and polyvinyl ether (ECP). Note that "poly(oxy)alkylene glycol or copolymers of its monoether and polyvinyl ether (ECP)" refers to a copolymer having constituent units derived from poly(oxy)alkylene glycol or its monoether and constituent units derived from polyvinyl ether, and "poly(oxy)alkylene glycol" refers to both polyalkylene glycol and polyoxyalkylene glycol.

[0062] The kinematic viscosity of component (A) used in one aspect of the present invention at 40°C is 20 mm, from the viewpoint of improving lubrication performance and sealing performance. 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 It is preferable to have a value of 150 mm or more, and from the viewpoint of improving the energy efficiency of the refrigeration oil composition, 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, 95mm ２ / s or less, 90mm ２ / s or less, 85mm ２ / s or less, 80mm ２ / s or less, or 75 mm ２ It is preferable to keep it below / s.

[0063] The kinematic viscosity of component (A) used in one aspect of the present invention is 2.0 mm at 100°C, from the viewpoint of improving lubrication performance and sealing performance. ２ / s or more, 3.0mm ２ / s or more, 4.0mm ２ / s or more, 4.5mm ２ / s or more, 5.0mm ２ / s or more, 5.5mm 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 It is preferable to have a value of 0 / s or higher, and from the viewpoint of improving the energy efficiency of the refrigeration oil composition, 50 mm ２ / s or less, 40mm ２ / s or less, 30mm ２ / s or less, 25mm ２ / s or less, 20mm ２ / s or less, 18mm ２ / s or less, 16mm ２ / s or less, 14mm ２ / s or less, 12mm ２ / s or less, 10mm ２ / s or less, 9.5mm ２ / s or less, or 9.0 mm ２ It is preferable to keep it below / s.

[0064] In one aspect of the present invention, the viscosity index of component (A) used is preferably 60 or higher, 65 or higher, 70 or higher, 75 or higher, 80 or higher, or 85 or higher, from the viewpoint of providing a refrigerant oil composition with small viscosity changes due to temperature changes. It may also be 200 or lower, 180 or lower, 160 or lower, 140 or lower, 120 or lower, or 100 or lower. In this specification, the kinematic viscosity and viscosity index of component (A) are values ​​measured or calculated in accordance with JIS K2283:2000.

[0065] In a refrigerant oil composition according to one embodiment of the present invention, the content of component (A) 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, or 93% by mass or more, based on the total amount (100% by mass) of the refrigerant oil composition, from the viewpoint of providing a refrigerant oil composition that can maintain long-term stability. It may also be less than 98.5% by mass, 98.0% by mass or less, 97.5% by mass or less, 97.0% by mass or less, 96.5% by mass or less, or 96.0% by mass or less, from the viewpoint of providing a refrigerant oil composition with excellent stability that can suppress the rise in acid value when mixed with a refrigerant by ensuring the content of components (B) and (C) in the refrigerant oil composition.

[0066] <Component (B): Epoxy Compound> A refrigeration oil composition according to one aspect of the present invention contains an epoxy compound represented by the following general formula (b-1) as component (B). Component (B) used in one aspect of the present invention may be used alone or in combination of two or more types.

[0067] In the above formula, R １ is a ring-forming cycloalkyl group having 3 to 12 carbon atoms, which may be substituted with an alkyl group having 1 to 24 carbon atoms, an alkenyl group having 2 to 24 carbon atoms, or an alkyl group having 1 to 6 carbon atoms, and is preferably an alkyl group having 1 to 24 carbon atoms. p is an integer from 0 to 4, preferably an integer from 1 to 3, more preferably 1 or 2, and even more preferably 1. q is 0 or 1, and is preferably 1. r is an integer from 0 to 10, preferably an integer from 0 to 5, more preferably an integer from 0 to 2, and even more preferably 1.

[0068] R １Examples of alkyl groups that can be selected include methyl group, ethyl group, propyl group (n-propyl group, isopropyl group), butyl group (n-butyl group, s-butyl group, t-butyl group, isobutyl group), pentyl group, hexyl group, heptyl group, octyl group, 2-ethylhexyl group, nonyl group, decyl group, undecyl group, dodecyl group, tridecyl group, tetradecyl group, hexadecyl group, octadecyl group, and the like. These alkyl groups may be linear alkyl groups or branched alkyl groups, but from the viewpoint of providing a refrigerant oil composition with excellent stability that can suppress the increase in acid value when mixed with a refrigerant, branched alkyl groups are preferred. The number of carbon atoms in the alkyl group is 1 to 24, from the viewpoint of providing a refrigerant oil composition with excellent stability that can suppress an increase in the acid value when mixed with a refrigerant, but is preferably 2 or more, 3 or more, 4 or more, 5 or more, 6 or more, or 7 or more, and is also preferably 20 or less, 18 or less, 16 or less, 14 or less, 12 or less, or 10 or less.

[0069] R １ Examples of the alkenyl groups that can be selected include ethenyl (vinyl) group, propenyl group, butenyl group, pentenyl group, hexenyl group, heptenyl group, octenyl group, nonenyl group, decenyl group, undecenyl group, dodecenyl group, tridecenyl group, tetradecenyl group, pentadecenyl group, hexadecenyl group, octadecenyl group, and the like. These alkenyl groups may be linear alkenyl groups or branched alkenyl groups. From the viewpoint of providing a refrigerant oil composition with excellent stability that can suppress the increase in acid value when mixed with a refrigerant, the number of carbon atoms in the alkenyl group is 2 to 24, but it is preferably 3 or more, 4 or more, 5 or more, 6 or more, or 7 or more, and also preferably 20 or less, 18 or less, 16 or less, 14 or less, 12 or less, or 10 or less.

[0070] R １Examples of cycloalkyl groups that can be selected include cyclopropyl, cyclobutyl, cyclopentyl, cyclohexyl, cycloheptyl, cyclooctyl, cyclononyl, cyclodecyl, cycloundecyl, and cyclododecyl groups. One or more hydrogen atoms of these cycloalkyl groups may be substituted with alkyl groups having 1 to 6 carbon atoms. Examples of substituted alkyl groups include R １ Among the alkyl groups that can be selected as described above, those having 1 to 6 carbon atoms are mentioned. The number of ring-forming carbon atoms of the cycloalkyl group is 3 to 12, but may be 4 or more, 5 or more, or 6 or more, or 10 or less, 8 or less, or 6 or less.

[0071] In one aspect of the present invention, component (B) used preferably contains a glycidyl ether (B1) having an alkyl group with 1 to 24 carbon atoms, from the viewpoint of providing a refrigerant oil composition with excellent stability that can suppress an increase in the acid value when mixed with a refrigerant. Component (B1) is p=q=r=1 in the general formula (b-1), and R １ The compound is an alkyl group having 1 to 24 carbon atoms. Specific examples of component (B1) include 2-ethylethylglycidyl ether, 2-methylhexylglycidyl ether, 2-ethylhexylglycidyl ether, 2-propylhexylglycidyl ether, 3-methylhexylglycidyl ether, 3-ethylhexylglycidyl ether, 3-propylhexylglycidyl ether, isononylglycidyl ether, caprinoylglycidyl ether, laurylglycidyl ether, myristylglycidyl ether, and the like. Among these, from the viewpoint of providing a refrigerant oil composition with excellent stability that can suppress an increase in acid value when mixed with a refrigerant, component (B1) is preferably a glycidyl ether having a branched alkyl group, more preferably a glycidyl ether having a branched alkyl group having 4 to 10 carbon atoms, and even more preferably 2-ethylhexylglycidyl ether.

[0072] In one aspect of the present invention, the content ratio of component (B1) in component (B) is preferably 50-100% by mass, 60-100% by mass, 70-100% by mass, 75-100% by mass, 80-100% by mass, 85-100% by mass, 90-100% by mass, 95-100% by mass, 99-100% by mass, or 100% by mass, based on the total amount (100% by mass) of component (B).

[0073] In a refrigerant oil composition according to one embodiment of the present invention, the content of component (B) is preferably more than 1.0% by mass on a basis of the total amount (100% by mass) of the refrigerant oil composition, from the viewpoint of providing a refrigerant oil composition with excellent stability that can suppress the rise in acid value when mixed with a refrigerant, and more preferably 1.2% by mass or more, 1.4% by mass or more, 1.5% by mass or more, 1.6% by mass or more, 1.7% by mass or more, 1.8% by mass or more, 1.9% by mass or more, or 2.0% by mass or more, from the viewpoint of providing a refrigerant oil composition with even better stability, and may also be 5.0% by mass or less, 4.8% by mass or less, 4.6% by mass or less, 4.4% by mass or less, 4.2% by mass or less, 4.0% by mass or less, 3.8% by mass or less, 3.6% by mass or less, 3.4% by mass or less, 3.2% by mass or less, 3.0% by mass or less, 2.8% by mass or less, or 2.6% by mass or less. Furthermore, if ingredient (B) is a combination of two or more ingredients, the content of ingredient (B) mentioned above refers to the total content of those two or more ingredients.

[0074] <Component (C): Unsaturated Compound> The refrigeration oil composition according to one aspect of the present invention contains an unsaturated compound having at least one double bond as component (C). The unsaturated compound may be a chain compound or a cyclic compound. In addition, component (C) used in one aspect of the present invention may be used alone or in combination of two or more types.

[0075] The double bond in component (C) used in one aspect of the present invention may be present in a chain structure or in a cyclic structure. Furthermore, if component (C) is a cyclic compound, the double bond may be present in the cyclic structure, outside the cyclic structure as a substituent of the cyclic structure, or both inside and outside the cyclic structure. Furthermore, the number of double bonds in component (C) used in one aspect of the present invention may be one or more, but from the viewpoint of providing a refrigerant oil composition with superior stability that can further suppress the rise in acid value when mixed with a refrigerant, it may be two or more, three or more, or four or more, or it may be 10 or less, nine or less, eight or less, seven or less, six or less, or five or less.

[0076] The group having a double bond as a substituent outside the cyclic structure of component (C) is preferably an aliphatic hydrocarbon group having a linear or branched olefin structure with 1 to 10 carbon atoms, for example, a methylene group (=CH₂). ２ ), vinyl group (-CH=CH ２ ), allyl group, propenyl group, isopropenyl group (1-methylvinyl group (-C(CH ３ ) = CH ２ Examples include the butenyl group, pentenyl group, hexenyl group, heptenyl group, octenyl group, nonenyl group, decenyl group, 1-methyl-2-butenyl group, 1-methyl-3-butenyl group, 1,2-dimethyl-3-pentenyl group, and 1,2-dimethyl-4-pentenyl group. Among these, the methylene group (=CH) is particularly important. ２ ), vinyl group (-CH=CH ２ ) or isopropenyl group (1-methylvinyl group (-C(CH ３ ) = CH ２ It is preferable that it be )).

[0077] In one embodiment of the present invention, when component (C) is a cyclic compound, the number of ring structures in the cyclic compound may be one or more. However, from the viewpoint of providing a refrigerant oil composition with superior stability that can further suppress the increase in acid value when mixed with a refrigerant, it is preferably 1 to 6, more preferably 1 to 4, and even more preferably 1 to 2.

[0078] In one aspect of the present invention, the carbon number of component (C) used is preferably 5 or more, or 8 or more, from the viewpoint of providing a refrigerant oil composition with superior stability that can further suppress the rise in acid value when mixed with a refrigerant. It is also preferable that the carbon number be 60 or less, 55 or less, 50 or less, 45 or less, 40 or less, 35 or less, 30 or less, 25 or less, or 20 or less.

[0079] In one aspect of the present invention, component (C) is a terpene compound (C1) having at least one isoprene-derived structural unit, a vinyl group (-CH=CH), and a vinyl group (-CH=CH) from the viewpoint of providing a refrigerant oil composition with superior stability that can further suppress the rise in acid value when mixed with a refrigerant. ２ Preferably, it is one or more selected from a vinyl compound (C2) having at least one ) and an unsaturated alicyclic compound (C3) having a cycloolefin structure, and a terpene compound (C1) having at least one isoprene-derived structural unit and a vinyl group (-CH=CH ２ It is more preferable that component (C) is selected from one or more vinyl compounds (C2) having at least one of the ) groups. Component (C) may be a compound having the structures of components (C1) and (C2), having both a terpene structure and a cycloolefin structure.

[0080] The isoprene-derived constituent units of component (C1) used in one aspect of the present invention may be contained in a chain structure, in a cyclic structure, or in both a chain structure and a cyclic structure. The number of isoprene-derived constituent units in component (C1) may be one or more, but from the viewpoint of obtaining a refrigerant oil composition with superior stability that can further suppress the rise in acid value when mixed with a refrigerant, it is preferably 1 to 10, more preferably 1 to 6, even more preferably 1 to 4, and even more preferably 1 to 3.

[0081] Specific components (C1) include, for example, pinene compounds, terpinene compounds, bisabolene compounds, farnesene compounds, and limonene oxide. Examples of pinene compounds include α-pinene and β-pinene. Examples of terpinene compounds include α-terpinene and γ-terpinene. Examples of bisabolene compounds include α-bisabolene, β-bisabolene, and γ-bisabolene. Examples of farnesene compounds include α-farnesene and β-farnesene.

[0082] In one aspect of the present invention, the component (C2) used is preferably a cycloalkane having at least one vinyl group and 3 to 12 ring-forming carbon atoms, more preferably a cycloalkane having 3 to 8 ring-forming carbon atoms, and even more preferably a cycloalkane having 5 to 6 ring-forming carbon atoms, from the viewpoint of providing a refrigerant oil composition with superior stability that can further suppress the rise in acid value when mixed with a refrigerant. Specific examples of component (C2) include vinylcycloalkanes such as 1,2,4-trivinylcyclohexane. The vinyl group of component (C2) may be 1 or more, or, from the viewpoint of providing a refrigerant oil composition with superior stability that can further suppress the rise in acid value when mixed with a refrigerant, preferably 2 to 6, more preferably 2 to 4, and even more preferably 2 to 3.

[0083] Examples of the component (C3) used in one aspect of the present invention include cycloalkenes having 3 to 12 ring-forming carbon atoms.

[0084] Component (C) used in one aspect of the present invention may be an unsaturated compound (C4) having at least one double bond and further having an epoxy structure. Examples of such component (C4) include alicyclic epoxy compounds represented by the following general formula (c-1).

[0085] In the above general formula (c-1), the alicyclic ring, shown as approximately circular, represents either a cycloalkene structure or a cycloalkane structure. From the viewpoint of providing a refrigerant oil composition with superior stability that can further suppress the increase in acid value when mixed with a refrigerant, the number of carbon atoms forming the cycloalkene ring is preferably 5 to 12, more preferably 5 to 10, and even more preferably 5 to 8. From the viewpoint of providing a refrigerant oil composition with superior stability that can further suppress the increase in acid value when mixed with a refrigerant, the number of carbon atoms forming the cycloalkene ring is preferably 5 to 12, more preferably 5 to 10, and even more preferably 5 to 8. Note that the two carbon atoms of the epoxy structure are also included in the number of carbon atoms forming the cycloalkene and cycloalkane rings.

[0086] In general formula (c-1), R ｃ１ This is an aliphatic unsaturated hydrocarbon group having a linear or branched olefin structure with 1 to 10 carbon atoms, for example, a methylene group (=CH₂). ２ ), vinyl group (-CH=CH ２ ), allyl group, propenyl group, isopropenyl group (1-methylvinyl group (-C(CH ３ ) = CH ２Examples of aliphatic unsaturated hydrocarbon groups include butenyl groups, pentenyl groups, hexenyl groups, heptenyl groups, octenyl groups, nonenyl groups, decenyl groups, 1-methyl-2-butenyl groups, 1-methyl-3-butenyl groups, 1,2-dimethyl-3-pentenyl groups, and 1,2-dimethyl-4-pentenyl groups. The aliphatic unsaturated hydrocarbon group may have one or more ether bonds, but from the viewpoint of providing a refrigerant oil composition with superior stability that can further suppress the increase in acid value when mixed with a refrigerant, it is preferable that the aliphatic unsaturated hydrocarbon group does not have ether bonds. Furthermore, the aliphatic unsaturated hydrocarbon group may be a substituent-containing aliphatic unsaturated hydrocarbon group or an unsubstituted aliphatic unsaturated hydrocarbon group, but it is preferable that the unsubstituted aliphatic unsaturated hydrocarbon group is. When the aliphatic unsaturated hydrocarbon group has substituents, examples of substituents include halogen atoms, hydroxyl groups, alkoxy groups, amino groups, imino groups, amide groups, and carboxyl groups. When an aliphatic unsaturated hydrocarbon group has multiple substituents, these substituents may be the same or different from one another. m is an integer of 0 or more, but is an integer of 1 or more when the alicyclic ring shown as approximately circular is a cycloalkane structure. m is preferably an integer from 0 to 6, more preferably an integer from 0 to 4, even more preferably an integer from 0 to 3, even more preferably an integer from 0 to 2, and particularly preferably 0 or 1.

[0087] Here, in general formula (c-1), when n is 1, R is used to make it easier to further improve the stability of the refrigeration oil composition. ２１ It is preferably an aliphatic hydrocarbon group having a linear olefin structure, and more preferably an aliphatic hydrocarbon group having a linear α-olefin structure. Furthermore, in general formula (c-1), when n is 1, from the viewpoint of making it easier to further improve the stability of the refrigeration oil composition, Ｃ１The number of carbon atoms is preferably 2 to 6, more preferably 2 to 3. Furthermore, when the alicyclic ring is a cyclohexane ring (i.e., when the cyclohexane skeleton containing the epoxy group is a 1,2-epoxycyclohexane skeleton), from the viewpoint of providing a refrigerant oil composition with superior stability that can further suppress the increase in acid value when mixed with a refrigerant, R Ｃ１ It is preferable that it is bonded to the 4-position of the cyclohexane ring.

[0088] In addition, in the general formula (c-1), R Ｃ２ R in an alicyclic ring Ｃ１ These substituents are other than R groups. Examples of such substituents include C1-C3 alkyl groups, halogen atoms, hydroxyl groups, alkoxy groups, amino groups, imino groups, amide groups, and carboxyl groups. Furthermore, n is an integer of 0 or more, preferably 0-5, more preferably 0-1, and even more preferably 0. When n is 2 or more, multiple R groups are used. Ｃ２ They may be the same or they may be different.

[0089] Note R ｃ１ and / or R ｃ２ If multiple R ｃ１ and / or R ｃ２ These atoms may bond to each other to form a ring structure. The formed ring structure is preferably a cycloalkane structure which may have substituents, or a cycloalkene structure which may have substituents. The number of carbon atoms in the ring-forming cycloalkane structure may be 3 or more, 4 or more, or 5 or more, and may also be 30 or less, 27 or less, 24 or less, 20 or less, 18 or less, 16 or less, 14 or less, 12 or less, 10 or less, 8 or less, or 6 or less. Examples of substituents that the cycloalkane structure may have include C1-C6 alkyl groups, halogen atoms, hydroxyl groups, alkoxy groups, amino groups, imino groups, amide groups, and carboxyl groups.

[0090] In one aspect of the present invention, component (C) used is preferably a refrigerant oil composition with superior stability that can further suppress the rise in acid value when mixed with a refrigerant, and is preferably one or more selected from pinene, limonene oxide, terpinene, bisabolene, cycloalkenes having 3 to 12 ring-forming carbon atoms and having an epoxy structure, farnesene, and cycloalkanes having 3 to 12 ring-forming carbon atoms and having at least one vinyl group.

[0091] In a refrigerant oil composition according to one aspect of the present invention, the content of component (C) is preferably 0.5% by mass or more, 0.7% by mass or more, 0.8% by mass or more, 0.9% by mass or more, 1.0% by mass or more, 1.2% by mass or more, or 1.4% by mass or more, based on the total amount (100% by mass) of the refrigerant oil composition, from the viewpoint of providing a refrigerant oil composition with superior stability that can further suppress the rise in acid value when mixed with a refrigerant, and more preferably 1.6% by mass or more, 1 The amount may be 8% by mass or more, 2.0% by mass or more, 2.2% by mass or more, 2.4% by mass or more, 2.8% by mass or more, or 3.0% by mass or more, or 10.0% by mass or less, 9.0% by mass or less, 8.0% by mass or less, 7.0% by mass or less, 6.0% by mass or less, 5.5% by mass or less, 5.0% by mass or less, 4.8% by mass or less, 4.6% by mass or less, 4.4% by mass or less, 4.2% by mass or less, 4.0% by mass or less, or 3.8% by mass or less. If component (C) is a combination of two or more components, the above content of component (C) means the total content of those two or more components.

[0092] <Various Additives> A refrigeration oil composition according to one embodiment of the present invention may further contain various additives, to the extent that they do not impair the effects of the present invention. As various additives, from the viewpoint of improving the stability of the refrigeration oil composition, one or more selected from the group consisting of antioxidants, extreme pressure agents, oiliness improvers, copper deactivators, rust inhibitors, defoamers, and viscosity index improvers may be included, and it is preferable that the composition contains antioxidants, extreme pressure agents, and defoamers.

[0093] In a refrigeration oil composition according to one aspect of the present invention, the content of each of these various additives can be appropriately adjusted within a range that does not impair the effects of the present invention. Based on the total amount (100% by mass) of the refrigeration oil composition, the content of each additive can be independently set to typically 0.001% by mass or more, 0.005% by mass or more, 0.01% by mass or more, 0.05% by mass or more, or 0.10% by mass or more, or 15% by mass or less, 10% by mass or less, 7.0% by mass or less, 5.0% by mass or less, 3.0% by mass or less, 2.0% by mass or less, or 1.0% by mass or less.

[0094] Furthermore, the refrigeration oil composition according to one embodiment of the present invention may limit the content of the above-mentioned specific additives. The content of the additives whose content is limited may be less than 5.0% by mass, less than 2.0% by mass, less than 1.0% by mass, less than 0.1% by mass, less than 0.01% by mass, less than 0.001% by mass, less than 0.0001% by mass, or less than 0.00001% by mass, based on the total amount (100% by mass) of the lubricating oil composition.

[0095] (Antioxidant) The antioxidant is preferably one or more selected from the group consisting of phenolic antioxidants and amine antioxidants. Examples of phenolic antioxidants include 2,6-di-tert-butyl-p-cresol (DBPC), 2,6-di-tert-butyl-4-ethylphenol, and 2,2'-methylenebis(4-methyl-6-tert-butylphenol). Examples of amine antioxidants include phenyl-α-naphthylamine and N,N'-diphenyl-p-phenylenediamine. Among these, 2,6-di-tert-butyl-p-cresol (DBPC) is preferred.

[0096] (Extreme Pressure Agents) Examples of extreme pressure agents 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, phosphite esters, acidic phosphite esters, and their amine salts. Specifically, examples include tricresyl phosphate (TCP), triphenyl phosphate, tri(nonylphenyl) phosphate, dioleyl hydrogen phosphate, and 2-ethylhexyl diphenyl phosphate. Examples of metal salts of carboxylic acids include metal salts of carboxylic acids having 3 to 60 carbon atoms. Preferably, metal salts of carboxylic acids having 3 to 30 carbon atoms are used. Among these, one or more selected from the group consisting of 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. As the metal constituting the metal salt, alkali metals and alkaline earth metals are preferred, and alkali metals are more preferred. Examples of sulfur-based extreme pressure agents include sulfurized oils and fats, sulfurized fatty acids, sulfurized esters, sulfurized olefins, dihydrocarbyl polysulfides, thiocarbamates, thioterpenes, and dialkylthiodipropionates. Among these, tricresyl phosphate (TCP) is preferred.

[0097] (Oil-enhancing agents) Examples of oil-enhancing agents include aliphatic saturated or 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 or unsaturated monoalcohols such as lauryl alcohol and oleyl alcohol; aliphatic saturated or unsaturated monoamines such as stearylamine and oleylamine; aliphatic saturated or unsaturated monocarboxylic acid amides such as lauric acid amide and oleic acid amide; and partial esters of polyhydric alcohols such as glycerin and sorbitol with aliphatic saturated or unsaturated monocarboxylic acids.

[0098] (Copper deactivators) Examples of copper deactivators include N-[N,N'-dialkyl (alkyl group with 3 to 12 carbon atoms) aminomethyl]triazole.

[0099] (Rust inhibitors) Examples of rust inhibitors include metal sulfonates, aliphatic amines, organic phosphites, organic phosphates, metal organic sulfonates, metal organic phosphates, alkenyl succinates, and polyhydric alcohols.

[0100] (Defoaming agents) Examples of defoaming agents include silicone-based defoaming agents such as silicone oil and fluorinated silicone oil.

[0101] (Viscosity index improvers) Examples of viscosity index improvers include polymethacrylate, polyisobutylene, ethylene-propylene copolymer, and styrene-diene hydrogenated copolymer.

[0102] [Uses of the Refrigerant Oil Composition] More specifically, the refrigerant oil composition of one aspect of the present invention is used in a refrigerator having a refrigeration cycle consisting of a compressor, condenser, expansion mechanism (expansion valve, etc.), and evaporator, or a compressor, condenser, expansion mechanism, dryer, and evaporator. The refrigerant oil composition of this embodiment is preferably used to lubricate sliding parts provided in, for example, a compressor. Therefore, one aspect of the present invention also provides a lubrication method using the refrigerant oil composition of this embodiment for lubrication parts inside a refrigerator. Furthermore, the refrigerant oil composition of one aspect of the present invention can be used, for example, in air conditioners, refrigerators, vending machines, display cases, refrigeration systems, hot water supply systems, or heating systems. 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. Here, as will be shown in the examples described later, the refrigerant oil composition of one aspect of the present invention exhibits excellent stability under extremely harsh autoclave test conditions, and is therefore particularly preferred for use in air conditioning equipment that performs heating and cooling operations.

[0103] The acid value (hereinafter also referred to as "acid value before stability test") of a refrigerant oil composition according to one embodiment of the present invention is preferably 1.00 mg KOH / g or less, 0.90 mg KOH / g or less, 0.80 mg KOH / g or less, 0.70 mg KOH / g or less, 0.60 mg KOH / g or less, 0.50 mg KOH / g or less, 0.40 mg KOH / g or less, 0.30 mg KOH / g or less, 0.20 mg KOH / g or less, 0.15 mg KOH / g or less, 0.10 mg KOH / g or less, 0.08 mg KOH / g or less, 0.06 mg KOH / g or less, or 0.04 mg KOH / g or less, from the viewpoint of providing a refrigerant oil composition with improved stability when mixed with a refrigerant.

[0104] In one embodiment of the present invention, the acid value of the refrigerant oil composition after a stability test when mixed with the refrigerant described below (hereinafter also referred to as the "acid value after the stability test") is preferably 1.60 mg KOH / g or less, 1.50 mg KOH / g or less, 1.40 mg KOH / g or less, 1.30 mg KOH / g or less, 1.20 mg KOH / g or less, 1.10 mg KOH / g or less, 1.00 mg KOH / g or less, 0.90 mg KOH / g or less, 0.80 mg KOH / g or less, 0.70 mg KOH / g or less, 0.60 mg KOH / g or less, 0.50 mg KOH / g or less, and 0.40 mg KOH / g or less, from the viewpoint of providing a refrigerant oil composition with improved stability when mixed with the refrigerant.

[0105] In one embodiment of the present invention, the difference between the acid value after the stability test and the acid value before the stability test is preferably 1.60 mg KOH / g or less, 1.50 mg KOH / g or less, 1.40 mg KOH / g or less, 1.30 mg KOH / g or less, 1.20 mg KOH / g or less, 1.10 mg KOH / g or less, 1.00 mg KOH / g or less, 0.90 mg KOH / g or less, 0.80 mg KOH / g or less, 0.70 mg KOH / g or less, 0.60 mg KOH / g or less, 0.50 mg KOH / g or less, and 0.40 mg KOH / g or less, from the viewpoint of obtaining a refrigerator mixed composition with excellent stability. In this specification, the acid value refers to the value measured by indicator photometric titration (see Annex 1 of the JIS standard) in accordance with JIS K2501:2003.

[0106] [Mixed Composition for Refrigeration Machines] A mixed composition for refrigeration machines according to one aspect of the present invention is a mixture containing the above-described refrigeration oil composition according to one aspect of the present invention and a refrigerant. In the mixed composition for refrigeration machines according to one aspect of the present invention, the mixing ratio of the refrigeration oil composition and the refrigerant [refrigeration oil composition / refrigerant] may be 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, or 45 / 55 or more by mass ratio, or 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, or 55 / 45 or less.

[0107] <Refrigerant> Examples of refrigerants included in the mixed composition for a refrigerator according to one embodiment of the present invention include unsaturated fluorinated hydrocarbon compounds (HFOs), saturated fluorinated hydrocarbon compounds (HFCs), natural refrigerants, and mixed refrigerants thereof. These refrigerants may be used individually or in combination of two or more types.

[0108] The refrigerant contained in the mixed composition for refrigerators according to one aspect of the present invention preferably contains at least an unsaturated fluorinated hydrocarbon compound. The refrigerant used in the mixed composition for refrigerators according to one aspect of the present invention may contain an unsaturated fluorinated hydrocarbon compound (HFO) of 1% by mass or more, 5% by mass or more, 10% by mass or more, 15% by mass or more, 20% by mass or more, 25% by mass or more, 30% by mass or more, 35% by mass or more, 40% by mass or more, 45% by mass or more, 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% by mass or more, or 100% by mass, based on the total amount of the refrigerant (100% by mass).

[0109] (Unsaturated Fluorinated Hydrocarbons (HFOs)) Examples of unsaturated fluorinated hydrocarbons include fluorinated hydrocarbons having carbon-carbon double bonds, such as fluorinated linear or branched linear or branched olefins with 2 to 6 carbon atoms, and fluorinated cyclic olefins with 4 to 6 ring-forming carbon atoms. More specifically, examples include ethylene in which 1 to 3 hydrogen atoms are replaced by fluorine atoms, propene in which 1 to 5 hydrogen atoms are replaced by fluorine atoms, butene in which 1 to 7 hydrogen atoms are replaced by fluorine atoms, pentene in which 1 to 9 hydrogen atoms are replaced by fluorine atoms, hexene in which 1 to 11 hydrogen atoms are replaced by fluorine atoms, cyclobutene in which 1 to 5 hydrogen atoms are replaced by fluorine atoms, cyclopentene in which 1 to 7 hydrogen atoms are replaced by fluorine atoms, and cyclohexene in which 1 to 9 hydrogen atoms are replaced by fluorine atoms. Among these, propene fluorides are preferred, propene in which 3 to 5 hydrogen atoms are substituted with fluorine atoms is more preferred, and propene in which 4 hydrogen atoms are substituted with fluorine atoms is even more preferred. Specifically, examples include 1,3,3,3-tetrafluoropropene (R1234ze) and 2,3,3,3-tetrafluoropropene (R1234yf). These unsaturated fluorinated hydrocarbon compounds may be used individually or in combination of two or more.

[0110] (Saturated Fluorinated Hydrocarbon Compounds (HFCs)) The saturated fluorinated hydrocarbon compounds are preferably fluorides of alkanes having 1 to 4 carbon atoms, more preferably fluorides of alkanes having 1 to 3 carbon atoms, and even more preferably fluorides of alkanes having 1 or 2 carbon atoms (methane or ethane). Examples of methane or ethane fluorides 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. Among these, it is preferable to include one or more selected from the group consisting of difluoromethane (R32) and 1,1-difluoroethane (R152a). These saturated fluorinated hydrocarbon compounds may be used individually or in combination of two or more. Examples of mixed refrigerants using two or more compounds 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).

[0111] (Mixed refrigerant of HFO and HFC) The refrigerant contained in the mixed composition for a refrigerator according to one aspect of the present invention may be a mixed solvent of the above-mentioned unsaturated fluorinated hydrocarbon compound (HFC) and saturated fluorinated hydrocarbon compound (HFC). Examples of such mixed solvents include R454A, obtained by mixing R32 / R1234yf in a 35 / 65 (mass ratio); R454B, obtained by mixing R32 / R1234yf in a 69 / 31 (mass ratio); R454C, obtained by mixing R32 / R1234yf in a 21.5 / 78.5 (mass ratio); R459A, obtained by mixing R32 / R1234yf / R1234ze in a 68 / 26 / 6 (mass ratio); R459B, obtained by mixing R32 / R1234yf / R1234ze in a 21 / 69 / 10 (mass ratio); and R32 / R1 R444A is obtained by mixing 234ze / R152a in a 12 / 83 / 5 (mass ratio), R445A is obtained by mixing R1234ze / R134a / R744 in a 85 / 9 / 6 (mass ratio), R446A is obtained by mixing R32 / R1234ze / R600a in a 68 / 29 / 3 (mass ratio), R447A is obtained by mixing R32 / R1234ze / R125 in a 68 / 28.5 / 3.5 (mass ratio), R447B is obtained by mixing R32 / R1234ze / R125 in a 68 / 24 / 8 (mass ratio), R32 / R1234yf R448A is obtained by mixing R1234ze / R134a / R125 in a mass ratio of 26 / 20 / 7 / 21 / 26, R449A is obtained by mixing R32 / 1234yf / R134a / R125 in a mass ratio of 24.3 / 25.3 / 25.7 / 24.7, R449C is obtained by mixing R32 / R1234yf / R134a / R125 in a mass ratio of 24.3 / 31 / 29 / 20, R450A is obtained by mixing R1234ze / R134a in a mass ratio of 58 / 42, R32 / R1234yf / R125 in a mass ratio of 67 / R452B is obtained by mixing R452 / R1234yf / R744 in a mass ratio of 26 / 7, R455A is obtained by mixing R32 / R1234ze / R134a in a mass ratio of 21.5 / 75.5 / 3, R456A is obtained by mixing R32 / R1234ze / R134a in a mass ratio of 6 / 49 / 45, R457A is obtained by mixing R32 / R1234yf / R152a in a mass ratio of 70 / 18 / 12, R458A is obtained by mixing R32 / R134a / R125 / R227ea / R236fa in a mass ratio of 20.5 / 61.4 / 4 / 13.5 / 0.6,R460B is obtained by mixing R32 / R1234ze / R134a / R125 in 28 / 27 / 20 / 25 (mass ratio), R460C is obtained by mixing R32 / R1234ze / R134a / R125 in 2.5 / 49 / 46 / 2.5 (mass ratio), R461A is obtained by mixing R32 / R1234ze / R134a / R125 in 12 / 22 / 14 / 52 (mass ratio), and R32 / R1234yf / R134a / R125 / R744 in 36 / 14 / 14 / 30 / 6 (mass ratio) Examples include R463A, obtained by mixing R32 / R1234ze / R125 / R227ea in a mass ratio of 27 / 40 / 27 / 6, R465A, obtained by mixing R32 / R1234yf / R290 in a mass ratio of 21 / 71.1 / 7.9, R464A, obtained by mixing R32 / R1234ze / R125 / R227ea in a mass ratio of 27 / 40 / 27 / 6, and R513A, obtained by mixing R1234yf / R134a in a mass ratio of 56 / 44.

[0112] (Natural refrigerants) Examples of natural refrigerants include hydrocarbon refrigerants (HC) and carbon dioxide (CO2). ２ One or more refrigerants selected from the group consisting of ), ammonia, water, and air are preferred, and hydrocarbon refrigerants are preferred. 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. When the number of carbon atoms is 8 or less, the boiling point of the refrigerant does not become too high, making it preferable as a refrigerant. Examples of hydrocarbon refrigerants include methane, ethane, ethylene, propane, cyclopropane, propylene, n-butane, isobutane, 2-methylbutane, n-pentane, neopentane, cyclopentane, etc. Hydrocarbon refrigerants may be used alone or in combination of two or more.

[0113] The present invention will be specifically described by the following examples. However, the present invention is not limited to the following examples. The methods for measuring each physical property are as follows: (1) Kinematic viscosity and viscosity index were measured and calculated in accordance with JIS K2283:2000. (2) Acid value was measured by indicator photometric titration in accordance with JIS K2501:2003 (see Annex 1 of the JIS standard).

[0114] Examples 1-14, Comparative Examples 1-5 Refrigerant oil compositions were prepared by adding each of the types of components shown in Tables 1-2 to the amounts shown in the same tables. Details of each component used in each example and comparative example are as follows: <Component (A): Base oil> ・"Et / iBu-PVE": Polyvinyl ether, a copolymer of ethyl vinyl ether and isobutyl vinyl ether, ISO viscosity grade = VG68, kinematic viscosity at 40°C = 70.2 mm ２ / s, 100℃ kinematic viscosity = 8.35mm ２ / s, viscosity index = 85. • "Et-PVE": Polyethyl vinyl ether, ISO viscosity grade = VG68, kinematic viscosity at 40°C = 71.0 mmHg ２ / s, 100℃ kinematic viscosity = 8.60mm ２ / s, viscosity index = 90. <Component (B): Epoxy compound> ・"2-ethylhexylglycidyl ether": A compound represented by the following formula (a). <Component (C): Unsaturated compound> ・"β-pinene": A compound represented by the following formula (b-i). ・"limonene oxide": A compound represented by the following formula (b-ii). ・"γ-terpinene": A compound represented by the following formula (b-iii). ・"α-bisabolene": A compound represented by the following formula (b-iv). ・"5,6-epoxy-1-cyclooctene": A compound represented by the following formula (b-v). ・"α-farnesene": A compound represented by the following formula (b-vi). ・"1,2,4-trivinylcyclohexane": A compound represented by the following formula (b-vii). <Other Additives> • Phenolic antioxidant: 2,6-di-tert-butyl-p-cresol (DBPC) • Extreme pressure agent: Tricresyl phosphate (TCP) • Antifoaming agent: Dimethyl silicone

[0115] The acid value of the prepared refrigerant oil composition was measured, and this value was defined as the "acid value before stability testing." The following stability tests were then conducted. The results are shown in Tables 1 and 2. <Stability Test> In autoclave containers (volume: 200 mL), Fe, Cu, and Al were placed as catalysts, and a mixture of 30 g of the refrigerant oil composition and 30 g of R1234yf refrigerant was filled into each to prepare a mixed composition for refrigeration. Then, 500 ppm by mass of water was added, the air content was set to 25 mL, and after being held at 200°C for 5 days, the acid value (mgKOH / g) of the refrigerant oil composition was measured, and this value was defined as the "acid value after stability testing." The difference between the "acid value after stability testing" and the "acid value before stability testing" was also calculated. The smaller the difference, the better the stability of the refrigerant oil composition when mixed with the refrigerant.

[0116]

[0117]

[0118] Tables 1-2 show that when the refrigeration oil compositions prepared in Examples 1-14 were mixed with R1234yf refrigerant and subjected to stability tests, the acid value after the test was suppressed to a lower level compared to Comparative Examples 1-5. Therefore, it can be said that the refrigeration oil compositions prepared in the examples have excellent stability when mixed with refrigerant.

Claims

1. Base oil (A), general formula (b-1) (In the above formula, R １ A refrigerant oil composition comprising an epoxy compound (B) represented by ( ), and an unsaturated compound (C) having at least one double bond, wherein the content of component (B) is greater than 1.0% by mass on a basis of the total amount of the refrigerant oil composition.

2. The refrigerant oil composition according to claim 1, wherein the content of component (B) is more than 1.0% by mass and 5.0% by mass or less on a total basis of the refrigerant oil composition.

3. The refrigerant oil composition according to claim 1 or 2, wherein the content of component (C) is 0.5% by mass or more and 10% by mass or less based on the total amount of the refrigerant oil composition.

4. The refrigeration oil composition according to any one of claims 1 to 3, wherein the mass ratio of component (B) to component (C) [(B) / (C)] is 0.10 or more and 5.00 or less.

5. The refrigeration oil composition according to any one of claims 1 to 4, wherein component (B) comprises a glycidyl ether (B1) having an alkyl group having 1 to 24 carbon atoms.

6. The refrigeration oil composition according to any one of claims 1 to 5, wherein component (C) is one or more selected from a terpene compound (C1) having at least one isoprene-derived structural unit, a vinyl compound (C2) having at least one vinyl group, and an unsaturated alicyclic compound (C3) having a cycloolefin structure.

7. The refrigeration oil composition according to any one of claims 1 to 6, wherein component (C) has an epoxy structure.

8. The refrigeration oil composition according to any one of claims 1 to 7, wherein component (C) comprises one or more selected from pinene, limonene oxide, terpinene, bisabolene, a cycloalkene having 3 to 12 ring-forming carbon atoms and having an epoxy structure, farnesene, and a cycloalkane having 3 to 12 ring-forming carbon atoms and having at least one vinyl group.

9. The refrigeration oil composition according to any one of claims 1 to 8, wherein component (A) comprises one or more selected from polyvinyl ethers (PVE), polyol esters (POE), and polyoxyalkylene glycols (PAG).

10. A mixed composition for a refrigerator containing the refrigerant oil composition and a refrigerant according to any one of claims 1 to 9.

11. The mixed composition for a refrigerator according to claim 10, wherein the refrigerant comprises an unsaturated fluorinated hydrocarbon compound.

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