Refrigerator oil composition and composition for refrigerator

Abstract

A refrigerator oil composition containing a base oil (A) and a phosphonic acid ester (B) represented by general formula (1) is used to provide a refrigerator oil composition having excellent wear resistance, seizure and burn resistance, and thermal stability. (In the formula, R1 and R2 each independently represent a C1-8 hydrocarbon group, and R3 represents a C9-40 hydrocarbon group optionally having a hydroxyl group as a substituent)

Description

TECHNICAL FIELD

[0001] The present application relates to a refrigerant oil composition and a composition for refrigerators. BACKGROUND

[0002] A refrigerator, such as a compression-type refrigerator, is generally composed of at least a compressor, a condenser, an expansion mechanism (expansion valve or the like), an evaporator, and the like, and exhibits a structure in which a mixture of a refrigerant and a refrigerant oil (hereinafter also referred to as "a composition for refrigerators") circulates in a closed system.

[0003] As a refrigerant used in a compression-type refrigerator, a fluorohydrocarbon compound having a low environmental burden has been increasingly used instead of a hydrogen chlorofluorocarbon (HCFC) that has been conventionally used. As the fluorohydrocarbon compound, a saturated fluorohydrocarbon compound (Hydro-Fluoro-Carbon; hereinafter also referred to as "HFC") such as 1,1,1,2-tetrafluoroethane (R134a), difluoromethane (R32), a mixture of difluoromethane and pentafluoroethane (R410A), and the like is commonly used.

[0004] In addition, an unsaturated fluorohydrocarbon compound (Hydro-Fluoro-Olefin; hereinafter also referred to as "HFO") such as 1,3,3,3-tetrafluoropropene (R1234ze), 2,3,3,3-tetrafluoropropene (R1234yf), and the like has also been studied.

[0005] Various additives have been blended into a refrigerant oil for the purpose of improving the lubricating properties of the refrigerant oil. Among them, tricresyl phosphate (hereinafter also referred to as "TCP") has been used as an additive for improving the wear resistance and the seizure resistance.

[0006] In addition, a refrigerant oil in which a phosphonate is blended as a phosphorus-based extreme pressure agent is disclosed in, for example, Patent Documents 1 and 2.

[0007] PRIOR ART DOCUMENTS PATENT DOCUMENTS Patent Document 1: International Publication No. 2018 / 021533 Patent Document 2: International Publication No. 2020 / 171135. SUMMARY

[0008] PROBLEMS TO BE SOLVED BY THE INVENTION However, the requirement for improving the effect of the wear resistance of a refrigerant oil is increasingly high, and an additive that can more improve the wear resistance and the seizure resistance than TCP and the phosphonate specifically described in the aforementioned patent documents is sought.

[0009] Further, the present inventors have found that, when a lubricating oil composition containing TCP is used as a refrigerant oil, a problem of an increase in the acid value of the lubricating oil composition at high temperatures occurs. This problem is particularly significant when an unsaturated hydro-fluoro-olefin compound (Hydro-Fluoro-Olefin; hereinafter also referred to as "HFO") such as 1,3,3,3-tetrafluoropropene (R1234ze), 2,3,3,3-tetrafluoropropene (R1234yf) or the like is used as a refrigerant, and improvement is desired.

[0010] The present application was made in view of the above-described problems, and an object thereof is to provide a refrigerant oil composition which is excellent in wear resistance, seizure resistance and thermal stability.

[0011] Means for solving the problems The present inventors have found as a result of intensive studies that a refrigerant oil composition containing a base oil and a specific phosphonate is capable of solving the above-described problems, and thus completed the present application. The present application was completed on the basis of this insight. That is, according to each embodiment of the present application, the following [1] to

[10] are provided.

[0012] [1] A refrigerant oil composition comprising a base oil (A) and a phosphonate (B) represented by the following general formula (1).

[0013] [Chemical Formula 1] (In the formula, R 1 and R 2 each independently represent a hydrocarbon group having 1 to 8 carbon atoms; R 3 represents a hydrocarbon group having 9 to 40 carbon atoms optionally having a hydroxyl group as a substituent.) [2] The refrigerant oil composition according to the above [1], wherein the content of the aforementioned phosphonate (B) is 200 to 4,000 mass ppm in terms of phosphorus atoms based on the total amount of the refrigerant oil composition.

[0014] [3] The refrigerant oil composition according to the above [1] or [2], wherein, in the aforementioned general formula (1), R 1 and R 2 represent an alkyl group having 1 to 4 carbon atoms or an alkenyl group having 2 to 4 carbon atoms; and R 3 represents a hydrocarbon group having 12 to 30 carbon atoms.

[0015] [4] The refrigerant oil composition according to any one of the above [1] to [3], wherein, in the aforementioned general formula (1), R 3 represents a linear or branched alkyl group or alkenyl group having 14 to 24 carbon atoms, or a group represented by the following general formula (2).

[0016] [Chemical formula 2] (In the formula, L 1 represents a single bond, -CH2- or -CH2CH2-; R 4 and R 5 each independently represents a hydrocarbon group having 2 to 10 carbon atoms.) [5] The refrigerant oil composition according to any one of the above [1] to [4], wherein the base oil (A) contains one or more selected from the group consisting of polyalkylene glycol (PAG), polyvinyl ether (PVE), polyol ester (POE) and mineral oil.

[0017] [6] The refrigerant oil composition according to any one of the above [1] to [5], further comprising an antioxidant (C).

[0018] [7] The refrigerant oil composition according to any one of the above [1] to [6], further comprising an acid scavenger (D).

[0019] [8] The refrigerant oil composition according to any one of the above [1] to [7], further comprising one or more selected from the group consisting of an oiliness improver, a copper deactivator, an antirust agent, an antifoaming agent and a viscosity index improver.

[0020] [9] A refrigerant composition comprising the refrigerant oil composition according to any one of the above [1] to [8] and a refrigerant.

[0021]

[10] The refrigerant composition according to the above [9], wherein the aforementioned refrigerant contains one or more selected from the group consisting of unsaturated fluorinated hydrocarbon refrigerant, saturated fluorinated hydrocarbon refrigerant, hydrocarbon refrigerant, carbon dioxide and ammonia.

[0022]

[11] The refrigerant composition according to the above

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

[0023]

[12] A method for producing a refrigerant oil composition, comprising a step of mixing a base oil (A) with a phosphonate (B) represented by the following general formula (1).

[0024] [Chemical formula 3] (In the formula, R 1 and R 2 each independently represents a hydrocarbon group having 1 to 8 carbon atoms; R 3 represents a hydrocarbon group having 9 to 40 carbon atoms optionally having a hydroxyl group as a substituent.) Effects of the Invention According to the present application, a refrigerant oil composition having excellent wear resistance, pick-up resistance, and heat stability can be provided. DETAILED DESCRIPTION

[0025] In the present specification, lower limit values and upper limit values which are sequentially described with respect to preferred numerical ranges (for example, ranges of contents, etc.) can each be independently combined. For example, according to the description "preferably 10 to 90, more preferably 30 to 60", "preferably the lower limit value (10)" and "more preferably the upper limit value (60)" can be combined to be "10 to 60". Similarly, in the present specification, values of "or more", "or less", "less than", and "more than" in connection with the description of numerical ranges are values which can be arbitrarily combined.

[0026] In the present specification, "hydrocarbon group" means a group consisting of only carbon atoms and hydrogen atoms, unless otherwise specified. "Hydrocarbon group" also includes "aliphatic group" consisting of straight chain or branched chain, "alicyclic group" having one or more saturated or unsaturated carbon rings which do not exhibit aromaticity, and "aromatic group" having one or more aromatic rings such as benzene ring which exhibit aromaticity.

[0027] In the present specification, "ring-forming carbon atom number" means the number of carbon atoms among atoms constituting the ring itself in a compound in which atoms are bonded to form a ring structure. In the case where the ring is substituted with a substituent, carbon included in the substituent is not included in the ring-forming carbon atom number.

[0028] Further, "ring-forming atom number" means the number of atoms constituting the ring itself in a compound in which atoms are bonded to form a ring structure. Atoms which do not constitute the ring (for example, hydrogen atoms which terminate the bond of the atom constituting the ring) and atoms included in the substituent when the ring is substituted with a substituent are not included in the ring-forming atom number.

[0029] Note that, in the present specification, "carbon atom number a to b" in the expression "substituted or unsubstituted X group having a carbon atom number a to b" means the number of carbon atoms when the X group is not substituted, and does not include the number of carbon atoms of the substituent when the X group is substituted.

[0030] [Refrigerant oil composition] The refrigerant oil composition of the present embodiment contains a base oil (A) and a phosphonate (B) represented by the following general formula (1).

[0031] [Chemical 4] (In the formula, R 1 and R 2 each independently represent a hydrocarbon group having 1 to 8 carbon atoms; R 3 represents a hydrocarbon group having 9 to 40 carbon atoms which optionally has a hydroxyl group as a substituent.

[0032] The present inventors have studied additives that can improve the wear resistance of refrigeration oils and have found that: 1 and R 2 , and a group with a large number of carbon atoms as R 3 The refrigeration oil composition containing the phosphonate exhibits excellent wear resistance and seizure resistance and shows good thermal stability.

[0033] On the other hand, a group having 8 or less carbon atoms is used as R 3 When phosphonates of a certain amount are used, sufficient effects of improving wear resistance and seizure resistance cannot be obtained.

[0034] In summary, the present inventors have found that the phosphonate (B) represented by the general formula (1) exhibits the effect of improving the wear resistance, seizure resistance and thermal stability of the composition for refrigerators.

[0035] In the refrigerating machine oil composition of the present embodiment, the total content of component (A) and component (B) is preferably 80 to 100 mass %, more preferably 85 to 100 mass %, further preferably 90 to 100 mass %, and even more preferably 95 to 100 mass %, based on the total amount (100 mass %) of the refrigerating machine oil composition.

[0036] Hereinafter, each component blended in the refrigerating machine oil composition of the present embodiment will be described.

[0037] <Base Oil (A)> The refrigerating machine oil composition of the present embodiment contains a base oil (A).

[0038] In the refrigeration oil composition of the present embodiment, the content of the base oil (A) is preferably 85.0% by mass or more, more preferably 90.0% by mass or more, and even more preferably 95.0% by mass or more, based on the total amount (100% by mass) of the refrigeration oil composition. It is also preferably 99.7% by mass or less, more preferably 99.3% by mass or less, and even more preferably 99.0% by mass or less. These lower and upper limits may be arbitrarily combined. Specifically, it is preferably 85.0 to 99.7% by mass, more preferably 90.0 to 99.3% by mass, and even more preferably 95.0 to 99.0% by mass.

[0039] As the base oil (A), for example, one or more selected from synthetic oils and mineral oils can be used.

[0040] As the base oil (A), from the viewpoint of improving the thermal stability of the refrigerant oil composition, it is preferable to contain one or more kinds selected from the group consisting of polyalkylene glycols (hereinafter also referred to as "PAG"), polyvinyl ethers (hereinafter also referred to as "PVE"), polyol esters (hereinafter also referred to as "POE"), and mineral oils (hereinafter also referred to as "base oil (Al)"), from the viewpoint of improving the compatibility with the refrigerant, the viewpoint of improving the hydrolysis resistance, and the viewpoint of improving the thermal stability of the refrigerant oil composition, it is more preferable to contain one or more kinds selected from the group consisting of PVE and PAG (hereinafter also referred to as "base oil (A2)"), from the viewpoint of improving the compatibility with the refrigerant, the viewpoint of improving the hydrolysis resistance, and the viewpoint of further improving the thermal stability of the refrigerant oil composition, it is further preferable to contain PAG (hereinafter also referred to as "base oil (A3)").

[0041] Hereinafter, PVE, PAG, POE, and mineral oil will be described in detail.

[0042] (Polyvinyl ethers (PVE)) PVE is only required to be a polymer having one or more structural units derived from a vinyl ether.

[0043] Note that, in the case where PVE is contained in the base oil (A), one kind of PVE can be used alone, or two or more kinds of PVE can be used in combination.

[0044] From the viewpoint of the compatibility with the refrigerant, PVE is preferably a polymer having one or more structural units derived from a vinyl ether, and having an alkyl group having 1 to 4 carbon atoms in the side chain. As the alkyl group, from the viewpoint of further improving the compatibility with the refrigerant, a methyl group or an ethyl group is preferable, and a methyl group is more preferable.

[0045] PVE is preferably a polymer having one or more structural units represented by the following general formula (A-1).

[0046] [Chemical Formula 5] In formula (A-1), R 1a , R 2a , and R 3a each independently represent a hydrogen atom or a hydrocarbon group having 1 to 8 carbon atoms. R 4a represents a divalent hydrocarbon group having 2 to 10 carbon atoms. R 5a represents a hydrocarbon group having 1 to 10 carbon atoms. r is the number of repeating units of OR 4a , and represents a number of 0 to 10, preferably a number of 0 to 5, more preferably a number of 0 to 3, and further preferably 0. Note that, in the case where a plurality of OR 4a are present in the structural unit represented by the above general formula (A-1), the plurality of OR4a Optionally the same or different.

[0047] as the hydrocarbon group represented by R 1a , R 2a , and R 3a , the number of carbon atoms is preferably 1 to 6, more preferably 1 to 3.

[0048] Here, "various" means "linear, branched, or cyclic" hydrocarbon groups, for example, "various butyl groups" means "n-butyl, sec-butyl, iso-butyl, t-butyl, cyclobutyl" and the like. Also, with respect to groups having a cyclic structure, positional isomers such as ortho, meta, and para isomers are included, and the same applies hereinafter.

[0049] R 1a , R 2a , and R 3a , the number of carbon atoms is preferably 1 to 6, more preferably 1 to 3.

[0050] R 1a , R 2a , and R 3a each independently are 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.

[0051] as the divalent hydrocarbon group represented by R 4a , the number of carbon atoms is preferably 2 to 10, more preferably 2 to 6.

[0052] R 4a , the number of carbon atoms is preferably 2 to 6, more preferably 2 to 4.

[0053] R 4aA divalent aliphatic group having preferably 2 to 10 carbon atoms, more preferably a divalent aliphatic group having 2 to 4 carbon atoms.

[0054] R1is a hydrocarbon group having 1 to 10 carbon atoms, and R2is a hydrogen atom or a hydrocarbon group having 1 to 10 carbon atoms. 5a As the hydrocarbon group having 1 to 10 carbon atoms, there can be mentioned alkyl groups such as methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, sec-butyl, t-butyl, various pentyl groups, various hexyl groups, various heptyl groups, various octyl groups, various nonyl groups, various decyl groups, and the like; cycloalkyl groups such as cyclopentyl, cyclohexyl, various methylcyclohexyl groups, various ethylcyclohexyl groups, various propylcyclohexyl groups, various dimethylcyclohexyl groups, and the like; aryl groups such as phenyl, various methylphenyl groups, various ethylphenyl groups, various dimethylphenyl groups, various propylphenyl groups, various trimethylphenyl groups, various butylphenyl groups, various naphthyl groups, and the like; aralkyl groups such as benzyl, various phenylethyl groups, various methylbenzyl groups, various phenylpropyl groups, various phenylbutyl groups, and the like.

[0055] R1is a hydrocarbon group having 1 to 10 carbon atoms, and R2is a hydrogen atom or a hydrocarbon group having 1 to 10 carbon atoms. 5a The number of carbon atoms of the hydrocarbon group is preferably 1 to 8, more preferably 1 to 6.

[0056] From the viewpoint of further improving the compatibility with the refrigerant, R1is preferably an alkyl group having 1 to 6 carbon atoms, more preferably an alkyl group having 1 to 4 carbon atoms, further preferably a methyl group or an ethyl group, and more further preferably a methyl group. 5a The number of carbon atoms of the hydrocarbon group is preferably 1 to 8, more preferably 1 to 6.

[0057] The number of units (the degree of polymerization) of the structural unit represented by the above general formula (A-1) is appropriately selected depending on the kinematic viscosity required for the base oil (A).

[0058] In addition, the polymer having the structural unit represented by the above general formula (A-1) can be a homopolymer having only one kind of the structural unit, or can be a copolymer having two or more kinds of the structural unit. Note that in the case where the polymer is a copolymer, there is no particular limitation as to the copolymerization form, and it can be any one of a block copolymer, a random copolymer, or a graft copolymer.

[0059] In addition, the PVE can include a polyalkylene glycol structure in its structure, and preferably does not include a polyalkylene glycol structure.

[0060] A monovalent group derived from a saturated hydrocarbon, an ether, an alcohol, a ketone, an amide, a nitrile, or the like can be introduced into the terminal portion of the polymer (A-1). Among these, the polymer (A-1) preferably has a group represented by the following general formula (A-1-i) as one terminal portion.

[0061] [Chemical Formula 6] In formula (A-1-i), * indicates the position bonded to the carbon atom in the structural unit represented by the above general formula (A-1).

[0062] In formula (A-1-i), R 6a , R 7a , and R 8a each independently represent 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, more preferably a hydrogen atom or an alkyl group having 1 to 3 carbon atoms.

[0063] As the hydrocarbon group having 1 to 8 carbon atoms represented by R 6a , R 7a , and R 8a , the same groups as those exemplified as the hydrocarbon group having 1 to 8 carbon atoms represented by R 1a , R 2a , and R 3a in the above general formula (A-1) can be exemplified.

[0064] In the above formula (A-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, more preferably a divalent aliphatic group having 2 to 4 carbon atoms.

[0065] In the above formula (A-1-i), r1 is the number of repeating units of OR 9a , and represents an integer of 0 to 10, preferably an integer of 0 to 5, more preferably an integer of 0 to 3, further preferably 0. Note that when a plurality of OR 9a are present in the structural unit represented by the above general formula (A-1-i), the plurality of OR 9a may be the same or different.

[0066] As the divalent hydrocarbon group having 2 to 10 carbon atoms represented by R 9a , the same groups as those exemplified as the divalent hydrocarbon group having 2 to 10 carbon atoms represented by R 4a in the above general formula (A-1) can be exemplified.

[0067] In formula (A-1-i), R 10a represents a hydrocarbon group having 1 to 10 carbon atoms, preferably a hydrocarbon group having 1 to 8 carbon atoms, more preferably an alkyl group having 1 to 8 carbon atoms.

[0068] Note that as R 10a , in 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, and in the case where r1 is 1 or more, an alkyl group having 1 to 4 carbon atoms is preferred.

[0069] As the hydrocarbon group having 1 to 10 carbon atoms represented by R 10a , the same groups as those exemplified as the hydrocarbon group having 1 to 10 carbon atoms represented by R 5aThe groups listed as the hydrocarbon group having 1 to 10 carbon atoms are the same as the groups listed above.

[0070] In addition, with respect to the polymer (A-1), when one of the terminal moieties is a group represented by the above general formula (A-1-i), the other terminal moiety is preferably any one of 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 ethylenic unsaturated bond.

[0071] [Chemical Formula 7] In formulae (A-1-ii) and (A-1-iii), R 6a , R 7a , R 8a , R 9a , R 10a and r1 are the same as the definitions described above in the general formula (A-1-i). In formula (A-1-ii), R 11a , R 12a and r2 are the same as the definitions described above in the general formula (A-1-i) for R 9a , R 10a and r1, respectively.

[0072] (Polyalkylene glycol (PAG)) As the PAG, a polymer (A-2) represented by the following general formula (A-2) is preferable.

[0073] R 13a -[ (OR 14a ) m -OR 15a ] n (A-2) Note that, in the case where the base oil (A) contains the PAG, one kind of PAG can be used alone, or two or more kinds of PAGs can be used in combination.

[0074] In the above general formula (A-2), R 13a represents a hydrogen atom, a monovalent hydrocarbon group having 1 to 10 carbon atoms, an acyl group having 2 to 10 carbon atoms, a 2- to 6-valent hydrocarbon group having 1 to 10 carbon atoms, or a substituted or unsubstituted heterocyclic group having 3 to 10 ring-forming atoms; R 14a represents an alkylene group having 2 to 4 carbon atoms; and R 15a 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.

[0075] As the substituent group optionally present on the heterocyclic group, there can be mentioned 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-forming carbon atoms (preferably 3 to 8, more preferably 5 or 6); an aryl group having 6 to 18 carbon atoms (preferably 6 to 12); a halogen atom (fluorine atom, chlorine atom, bromine atom, iodine atom); a cyano group; a nitro group; a hydroxyl group; an amino group; and the like.

[0076] These substituent groups are optionally further substituted with any of the above substituent groups.

[0077] n is an integer of 1 to 6, preferably an integer of 1 to 3, more preferably 1.

[0078] Note that n is determined in accordance with the number of bonding sites of R 13a in the above general formula (A-2). For example, in the case where R 13a is an alkyl group or an acyl group, n becomes 1, and R 13a is a hydrocarbon group or a heterocyclic group, in the case where the valence of the group is 2, 3, 4, 5, or 6, n becomes 2, 3, 4, 5, or 6, respectively.

[0079] m is the number of repeating units of OR 14a , and represents a number of 1 or more, preferably a number in which m x n becomes 6 to 80. Note that the value of m is a value appropriately set in such a manner that the kinematic viscosity of the base oil (A) at 100°C falls within the range of 2 to 50 mm 2 / s, and is not particularly limited as long as it is adjusted in such a manner that the kinematic viscosity falls within the prescribed range.

[0080] Note that a plurality of R 14a are optionally the same as or different from each other. Also, in the case where n is 2 or more, a plurality of R 15a in one molecule are optionally the same as or different from each other.

[0081] As the above monovalent hydrocarbon group represented by R 13a and R 15a , there can be mentioned a methyl group, an ethyl group, a n-propyl group, an i-propyl group, a n-butyl group, an i-butyl group, a sec-butyl group, a t-butyl group, various kinds of pentyl groups, various kinds of hexyl groups, various kinds of heptyl groups, various kinds of octyl groups, various kinds of nonyl groups, various kinds of decyl groups, and the like alkyl groups; a cyclopentyl group, a cyclohexyl group, various kinds of methylcyclohexyl groups, various kinds of ethylcyclohexyl groups, various kinds of propylcyclohexyl groups, various kinds of dimethylcyclohexyl groups, and the like cycloalkyl groups; a phenyl group, various kinds of methylphenyl groups, various kinds of ethylphenyl groups, various kinds of dimethylphenyl groups, various kinds of propylphenyl groups, various kinds of trimethylphenyl groups, various kinds of butylphenyl groups, various kinds of naphthyl groups, and the like aryl groups; a benzyl group, various kinds of phenylethyl groups, various kinds of methylbenzyl groups, various kinds of phenylpropyl groups, various kinds of phenylbutyl groups, and the like arylalkyl groups. Note that the above alkyl group can be either a straight chain or a branched chain.

[0082] From the perspective of compatibility with refrigerants, R 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.

[0083] R 13a and R 15a The hydrocarbon group portion of the acyl group having 2 to 10 carbon atoms shown in the figure may be any of linear, branched or cyclic. Examples of the alkyl group include the above-mentioned R 13a and R 15a The alkyl portion having 1 to 9 carbon atoms in the hydrocarbon group shown.

[0084] From the perspective of compatibility with refrigerants, R 13a and R 15a The number of carbon atoms in the acyl group is preferably 2 to 8, more preferably 2 to 6.

[0085] As R 13a The above-mentioned 2 to 6-valent hydrocarbon groups shown in 13a residues obtained by removing 1 to 5 hydrogen atoms from the monovalent hydrocarbon group shown; residues obtained by removing hydroxyl groups from polyols such as trimethylolpropane, glycerol, pentaerythritol, sorbitol, 1,2,3-trihydroxycyclohexane, and 1,3,5-trihydroxycyclohexane; and the like.

[0086] From the perspective of compatibility with refrigerants, R 13a The di- to hexavalent acyl group represented by ≠ ...

[0087] As R 13a and R 15a The heterocyclic group shown above is preferably a heterocyclic group containing an oxygen atom or a heterocyclic group containing a sulfur atom. It should be noted that the heterocyclic group may be a saturated ring or an unsaturated ring.

[0088] Examples of the oxygen-containing heterocyclic group include residues obtained by removing 1 to 6 hydrogen atoms from a saturated heterocyclic ring containing an oxygen atom such as ethylene oxide, 1,3-propylene oxide, tetrahydrofuran, tetrahydropyran, and hexamethylene oxide; and an unsaturated heterocyclic ring containing an oxygen atom such as acetylene oxide, furan, pyran, oxycycloheptatriene, isobenzofuran, and isochromene.

[0089] Examples of the sulfur-containing heterocyclic group include residues obtained by removing 1 to 6 hydrogen atoms from saturated heterocyclic rings containing a sulfur atom such as ethylene sulfide, thietane, tetrahydrothiophene, tetrahydrothiopyran, and thiepane, and unsaturated heterocyclic rings containing a sulfur atom such as ethylene sulfide, thiophene, thiopyran, and thiotripyridine.

[0090] R 13a and R 15a The above heterocyclic group optionally has a substituent which is optionally bonded to the oxygen atom in the above general formula (A-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.

[0091] From the viewpoint of compatibility with the refrigerant, the number of ring-forming atoms of the above heterocyclic group is preferably 3 to 10, and more preferably 3 to 6.

[0092] As the above alkylene group represented by R 14a , dimethylene group (-CH2CH2-), ethylene group (-CH(CH3)-), and the like alkylene groups having 2 carbon atoms; trimethylene group (-CH2CH2CH2-), propylene group (-CH(CH3)CH2-), propylidene group (-CHCH2CH3-), isopropylidene group (-C(CH3)2-), and the like alkylene groups having 3 carbon atoms; tetramethylene group (-CH2CH2CH2CH2-), 1-methyltrimethylene group (-CH(CH3)CH2CH2-), 2-methyltrimethylene group (-CH2CH(CH3)CH2-), butylene group (-C(CH3)2CH2-), and the like alkylene groups having 4 carbon atoms can be exemplified. Among these, as R 14a , propylene group (-CH(CH3)CH2-) is preferred.

[0093] Note that in the polymer (A-2) represented by the above general formula (A-2), the content of the oxypropylene unit (-OCH(CH3)CH2-) is preferably 50 mol% or more, more preferably 65 mol% or more, and further preferably 80 mol% or more, based on the total amount (100 mol%) of the oxyalkylene group (OR 14a ) in the polymer (A-2).

[0094] Among the polymers (A-2) represented by the above general formula (A-2), one or more selected from the group consisting of a polyoxypropylene glycol dimethyl ether represented by the following general formula (A-2-i), a polyoxyethylene polyoxypropylene glycol dimethyl ether represented by the following general formula (A-2-ii), a polyoxypropylene glycol monobutyl ether represented by the following general formula (A-2-iii), and a polyoxypropylene glycol diacetate is preferred.

[0095] [Chemical Formula 8] (In formula (A-2-i), m1 represents a number of 1 or more, and is preferably a number of 6 to 80.).

[0096] [Chemical Formula 9] (In formula (A-2-ii), each of m2 and m3 independently represents a number of 1 or more, and preferably the value of m2 + m3 is a number of 6 to 80.)

[0097] [Chemical 10] (In formula (A-2-iii), m4 represents a number of 1 or more, and preferably a number of 6 to 80.)

[0098] Note that 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) are appropriately selected depending on the kinematic viscosity required for base oil (A).

[0099] (polyhydric alcohol ester (POE)) As the POE, an ester of a diol or a polyhydric alcohol and a fatty acid can be exemplified. Note that in the case where the base oil (A) contains the POE, the POE can be used alone as one kind or in combination with two or more kinds.

[0100] The POE is preferably an ester of a diol or a polyhydric alcohol having a hydroxyl group number of 3 to 20 and a fatty acid having a carbon atom number of 3 to 20.

[0101] As the diol, 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, 1,12-dodecanediol, and the like can be exemplified.

[0102] As the polyhydric alcohol, trimethylol ethane, trimethylol propane, trimethylol butane, di(trimethylol propane), tri(trimethylol propane), pentaerythritol, di(pentaerythritol), tri(pentaerythritol), glycerol, polyglycerol (2 to 20 polymer of glycerol), 1,3,5-pentanetriol, sorbitol, sorbitan, sorbitol glycerin condensate, heliotrope alcohol, arabitol, xylitol, mannitol, and the like polyhydric alcohols; xylose, arabinose, ribose, rhamnose, glucose, fructose, galactose, mannose, sorbose, cellobiose, maltose, isomaltose, trehalose, sucrose, raffinose, gentiobiose, sambunigrin, and the like sugars; and partial etherates thereof, methyl glucoside (glycoside), and the like can be exemplified.

[0103] Among these, preferred are hindered alcohols such as neopentyl glycol, trimethylol ethane, trimethylol propane, trimethylol butane, di(trimethylol propane), tri(trimethylol propane), pentaerythritol, di(pentaerythritol), tri(pentaerythritol), and the like. Note that a hindered alcohol refers to an alcohol having a quaternary carbon atom bonded to 4 carbon atoms.

[0104] The number of carbon atoms of the fatty acid is preferably 3 or more, more preferably 4 or more, further preferably 5 or more, and more further preferably 8 or more from the viewpoint of lubricating properties, and is preferably 20 or less, more preferably 16 or less, further preferably 12 or less, and more further preferably 10 or less from the viewpoint of compatibility with the refrigerant.

[0105] Note that the number of carbon atoms of the above fatty acid also includes the carbon atom of the carboxyl group (-COOH) possessed by the fatty acid.

[0106] In addition, the fatty acid can be either a straight-chain fatty acid or a branched-chain fatty acid, and is preferably a straight-chain fatty acid from the viewpoint of lubricating properties, and is preferably a branched-chain fatty acid from the viewpoint of hydrolysis stability. Furthermore, the fatty acid can be either a saturated fatty acid or an unsaturated fatty acid.

[0107] As the fatty acid, straight-chain or branched-chain fatty acids such as isobutyric acid, propionic acid, butyric acid, valeric 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, eicosanoic acid, oleic acid, or so-called neo acids in which the α carbon atom is a quaternary carbon, or the like can be exemplified.

[0108] More specifically, isobutyric acid, valeric acid (n-valeric acid), hexanoic acid (n-hexanoic acid), heptanoic acid (n-heptanoic acid), octanoic acid (n-octanoic acid), nonanoic acid (n-nonanoic acid), decanoic acid (n-decanoic acid), oleic acid (cis-9-octadecenoic acid), isovaleric acid (3-methylbutyric acid), 2-methylhexanoic acid, 2-ethylvaleric acid, 2-ethylhexanoic acid, 3,5,5-trimethylhexanoic acid, and the like are preferred.

[0109] The POE can be a partial ester in which a part of the plurality of hydroxyl groups possessed by the polyol remains unesterified, or can be a total ester in which all of the hydroxyl groups are esterified. In addition, the POE can be a mixture of a partial ester and a total ester, and is preferably a total ester.

[0110] As the POE, from the viewpoint of more excellent hydrolysis stability, esters of a hindered alcohol such as neopentyl glycol, trimethylol ethane, trimethylol propane, trimethylol butane, di (trimethylol propane), tri (trimethylol propane), pentaerythritol, di (pentaerythritol), tri (pentaerythritol), and the like are preferred, and esters of neopentyl glycol, trimethylol ethane, trimethylol propane, trimethylol butane, pentaerythritol are more preferred, and further, from the viewpoint of particularly excellent compatibility with the refrigerant and hydrolysis stability, esters of pentaerythritol are further preferred.

[0111] As specific examples of the preferred POE, diesters of neopentyl glycol with one or two or more kinds of fatty acids selected from the group consisting of isobutyric acid, valeric acid, hexanoic acid, heptanoic acid, octanoic acid, nonanoic acid, decanoic acid, oleic acid, isovaleric acid, 2-methyl hexanoic acid, 2-ethyl valeric acid, 2-ethyl hexanoic acid, and 3, 5, 5-trimethyl hexanoic acid; triesters of trimethylol ethane with one or two or more kinds of fatty acids selected from the group consisting of isobutyric acid, valeric acid, hexanoic acid, heptanoic acid, octanoic acid, nonanoic acid, decanoic acid, oleic acid, isovaleric acid, 2-methyl hexanoic acid, 2-ethyl valeric acid, 2-ethyl hexanoic acid, and 3, 5, 5-trimethyl hexanoic acid; triesters of trimethylol propane with one or two or more kinds of fatty acids selected from the group consisting of isobutyric acid, valeric acid, hexanoic acid, heptanoic acid, octanoic acid, nonanoic acid, decanoic acid, oleic acid, isovaleric acid, 2-methyl hexanoic acid, 2-ethyl valeric acid, 2-ethyl hexanoic acid, and 3, 5, 5-trimethyl hexanoic acid; triesters of trimethylol butane with one or two or more kinds of fatty acids selected from the group consisting of isobutyric acid, valeric acid, hexanoic acid, heptanoic acid, octanoic acid, nonanoic acid, decanoic acid, oleic acid, isovaleric acid, 2-methyl hexanoic acid, 2-ethyl valeric acid, 2-ethyl hexanoic acid, and 3, 5, 5-trimethyl hexanoic acid; tetraesters of pentaerythritol with one or two or more kinds of fatty acids selected from the group consisting of isobutyric acid, valeric acid, hexanoic acid, heptanoic acid, octanoic acid, nonanoic acid, decanoic acid, oleic acid, isovaleric acid, 2-methyl hexanoic acid, 2-ethyl valeric acid, 2-ethyl hexanoic acid, and 3, 5, 5-trimethyl hexanoic acid, and the like can be mentioned.

[0112] Note that the ester with two or more kinds of fatty acids can be a substance obtained by mixing two or more kinds of esters of a fatty acid with a polyol. Among the POEs, from the viewpoint of improving low-temperature characteristics and compatibility with the refrigerant, esters of a mixed fatty acid with a polyol are preferred.

[0113] (mineral oil) As the mineral oil, for example, oils refined by subjecting a lubricating oil fraction obtained by subjecting a paraffin-based, middle-base, or naphthenic-based crude oil to atmospheric distillation or subjecting atmospheric residue obtained by subjecting a crude oil to atmospheric distillation to vacuum distillation to one or more treatments among solvent deasphalting, solvent extraction, hydrocracking, solvent dewaxing, contact dewaxing, hydrogenation refining, and the like; oils manufactured by subjecting a mineral oil-based wax to isomerization, and the like can be mentioned.

[0114] Note that, in the case where the base oil (A) contains a mineral oil, one kind of mineral oil can be used alone, or two or more kinds of mineral oils can be used in combination.

[0115] The main component of the base oil (A) in the refrigerant oil composition of the present embodiment is preferably the aforementioned base oil (A1), more preferably the aforementioned base oil (A2), and further preferably the aforementioned base oil (A3). Note that, in the present specification, the "main component" refers to the component having the highest content.

[0116] The content of the base oil (A1), the base oil (A2), or the base oil (A3) in the base oil (A) is preferably 50 to 100% by mass, more preferably 60 to 100% by mass, further preferably 70 to 100% by mass, more further preferably 80 to 100% by mass, and still further preferably 90 to 100% by mass, based on the total amount (100% by mass) of the base oil (A).

[0117] In particular, the content of the base oil (A3) in the base oil (A) is preferably 50 to 100% by mass, more preferably 60 to 100% by mass, further preferably 70 to 100% by mass, more further preferably 80 to 100% by mass, and still further preferably 90 to 100% by mass.

[0118] In the base oil (A), in addition to the base oil (A1), the base oil (A2), or the base oil (A3), other base oils can also be contained.

[0119] As the other base oils, synthetic oils such as polyester-based, polycarbonate-based, hydrogenated products of α-olefin oligomers, alicyclic hydrocarbon compounds, alkylated aromatic hydrocarbon compounds, copolymers of poly(oxy)alkylene glycol or monoether thereof and polyvinyl ether (ECP), and the like other than the aforementioned PVE, PAG, and POE can be exemplified.

[0120] Note that, the "copolymer of poly(oxy)alkylene glycol or monoether thereof and polyvinyl ether (ECP)" refers to a copolymer having a structural unit derived from poly(oxy)alkylene glycol or monoether thereof and a structural unit derived from polyvinyl ether, and "poly(oxy)alkylene glycol" refers to both polyalkylene glycol and polyoxyalkylene glycol.

[0121] The 40°C kinematic viscosity of the base oil (A) is preferably 5 to 120 mm 2 / s, more preferably 10 to 110 mm 2 / s, further preferably 30 to 100 mm 2 / s. If the 40°C kinematic viscosity of the base oil (A) is within the aforementioned range, the wear resistance becomes more excellent.

[0122] In the present specification, the kinematic viscosity at 40°C is a value measured in accordance with JIS K 2283:2000 using a glass capillary viscometer.

[0123] <Phosphonate (B)> The refrigerant oil composition of the present embodiment contains a phosphonate (B) represented by the following general formula (1).

[0124] [Chemical 11] (In the formula, R 1 and R 2 each independently represent a hydrocarbon group having 1 to 8 carbon atoms; R 3 represents a hydrocarbon group having 9 to 40 carbon atoms optionally having a hydroxyl group as a substituent.

[0125] It is considered that the phosphonate (B) represented by the above general formula (1) is a compound in which R 1 and R 2 are small groups that play a role of adsorbing to a metal surface, and on the other hand, R 3 toward the inside of an oil film is a bulky group, thereby imparting good wear resistance. It is also presumed that by making R 1 , R 2 , and R 3 all be hydrocarbon groups optionally having a hydroxyl group as a substituent, the thermal stability of the refrigerant oil composition is not impaired.

[0126] In the above general formula (1), as the hydrocarbon group having 1 to 8 carbon atoms represented by R 1 and R 2 , there can be mentioned an alkyl group having 1 to 8 carbon atoms, an alkenyl group having 2 to 8 carbon atoms, an alkynyl group having 2 to 8 carbon atoms, a cycloalkyl group having 6 to 8 carbon atoms, an alkylcycloalkyl group having 6 to 8 carbon atoms, an aryl group having 6 to 8 carbon atoms, and the like, among which, an alkyl group having 1 to 8 carbon atoms, which is substituted or unsubstituted, is preferred, an alkyl group having 1 to 4 carbon atoms is more preferred, and a methyl group or an ethyl group is particularly preferred.

[0127] As the aforementioned alkyl group having 1 to 8 carbon atoms, there can be mentioned a methyl group, an ethyl group, an n-propyl group, an iso-propyl group, an n-butyl group, an iso-butyl group, a sec-butyl group, a t-butyl group, various kinds of pentyl groups, various kinds of hexyl groups, and the like. Note that the aforementioned alkyl group can be either of a straight chain or a branched chain.

[0128] As the aforementioned cycloalkyl group having 6 to 8 carbon atoms, there can be mentioned a cyclohexyl group, a cycloheptyl group, a cyclooctyl group.

[0129] As the aforementioned alkylcycloalkyl group having 6 to 8 carbon atoms, there can be mentioned various kinds of methylcyclohexyl groups, various kinds of ethylcyclohexyl groups, various kinds of dimethylcyclohexyl groups, and the like.

[0130] As the aryl group having 6 to 8 carbon atoms, a substituted or unsubstituted phenyl group can be exemplified, and specifically, a phenyl group, various methylphenyl groups, and various dimethylphenyl groups can be exemplified.

[0131] In the general formula (1), R 3 As the hydrocarbon group having 9 to 40 carbon atoms optionally having a hydroxyl group as a substituent, a substituted or unsubstituted alkyl group having 9 to 40 carbon atoms, a substituted or unsubstituted alkenyl group having 9 to 40 carbon atoms, a substituted or unsubstituted alkynyl group having 9 to 40 carbon atoms, a substituted or unsubstituted cycloalkyl group having 9 to 40 carbon atoms, a substituted or unsubstituted alkylcycloalkyl group having 9 to 40 carbon atoms, a substituted or unsubstituted aryl group, and the like can be exemplified, and among these, a substituted or unsubstituted alkyl group having 9 to 40 carbon atoms and a substituted or unsubstituted aryl group are preferable.

[0132] The substituent optionally present in the aforementioned various hydrocarbon groups is a hydroxyl group.

[0133] As the substituted or unsubstituted alkyl group having 9 to 40 carbon atoms, various nonyl groups, various decyl groups, and the like can be exemplified. Note that the aforementioned alkyl group can be either linear or branched.

[0134] As the substituted or unsubstituted aryl group having 9 to 40 carbon atoms, a substituted or unsubstituted phenyl group, a substituted or unsubstituted naphthyl group, and the like can be exemplified, and among these, a substituted or unsubstituted phenyl group is preferable.

[0135] From the aforementioned viewpoint, R 1 and R 2 each independently preferably an alkyl group having 1 to 4 carbon atoms or an alkenyl group having 2 to 4 carbon atoms.

[0136] On the other hand, R 3 in the aforementioned general formula (1) is preferably a hydrocarbon group having 12 to 30 carbon atoms optionally having a hydroxyl group as a substituent, and specifically, more preferably a linear or branched alkyl group or alkenyl group having 14 to 24 carbon atoms, or a group represented by the following general formula (2).

[0137] [Chemical Formula 12] (In the formula, L 1 represents a single bond, -CH2-, or -CH2CH2-; R 4 and R 5 each independently represents a hydrocarbon group having 2 to 10 carbon atoms.) In the case where the aforementioned R 3 is a group represented by the aforementioned general formula (2), from the viewpoint of heat stability, R4 and R 5 is preferably a bulky group to some extent. As these R 4 and R 5 is more preferably a hydrocarbon group having 3 to 8 carbon atoms.

[0138] In the above general formula (2), as the hydrocarbon group having 2 to 10 carbon atoms represented by R 4 or R 5 atoms, a cycloalkyl group having 6 to 10 carbon atoms, an alkylcycloalkyl group having 6 to 10 carbon atoms, an aryl group having 6 to 10 carbon atoms, and the like, among which a substituted or unsubstituted alkyl group having 2 to 10 carbon atoms is preferred, a hydrocarbon group having 3 to 6 carbon atoms is more preferred, and a tert-butyl group is particularly preferred.

[0139] As the above alkyl group having 2 to 10 carbon atoms, an alkyl group such as ethyl, n-propyl, isopropyl, n-butyl, isobutyl, sec-butyl, tert-butyl, various kinds of pentyl groups, various kinds of hexyl groups, various kinds of heptyl groups, various kinds of octyl groups, various kinds of nonyl groups, various kinds of decyl groups, and the like; a cycloalkyl group such as cyclopentyl, cyclohexyl, various kinds of methylcyclohexyl groups, various kinds of ethylcyclohexyl groups, various kinds of propylcyclohexyl groups, various kinds of dimethylcyclohexyl groups, and the like can be exemplified. Note that the above alkyl group can be either straight-chain or branched.

[0140] The number of carbon atoms of the above alkyl group is preferably 2 to 10, more preferably 3 to 8.

[0141] As the above substituted or unsubstituted aryl group having 6 to 10 carbon atoms, a substituted or unsubstituted phenyl group, a naphthyl group, and the like can be exemplified.

[0142] In the refrigerant oil composition of the present embodiment, from the viewpoint of improving wear resistance, the content of component (B) is preferably 200 mass ppm or more, more preferably 300 mass ppm or more, further preferably 400 mass ppm or more, particularly preferably 500 mass ppm or more, in terms of phosphorus atoms derived from component (B), based on the total amount of the refrigerant oil composition, and is preferably 3,000 mass ppm or less, more preferably 2,400 mass ppm or less, further preferably 2,000 mass ppm or less, particularly preferably 1,500 mass ppm or less, and these upper and lower limits can be combined arbitrarily, and specifically, it is preferably 200 to 3,000 mass ppm, more preferably 300 to 2,400 mass ppm, further preferably 400 to 2,000 mass ppm, particularly preferably 500 to 1,500 mass ppm.

[0143] The component (B) used in the refrigerant oil composition of the present embodiment has a hydrocarbon group optionally having a hydroxyl group as a substituent, and thus has excellent thermal stability, and can be contained in a large amount.

[0144] <additives> The refrigerant oil composition of the present embodiment can further contain an additive.

[0145] As the additive, from the viewpoint of improving the stability of the refrigerant oil composition, it is preferable to contain one or more selected from the group consisting of an antioxidant, an oiliness improver, an oxygen scavenger, an acid scavenger, a copper deactivator, an antirust agent, an antifoaming agent, and a viscosity index improver, and it is more preferable to contain at least an antioxidant. In addition, the refrigerant oil composition of the present embodiment can contain an extreme pressure agent other than the component (B).

[0146] Each of these additives can be used alone or two or more of them can be used in combination.

[0147] The total content of these additives is preferably 0 to 10 mass%, more preferably 0.01 to 8.0 mass%, and further preferably 0.1 to 5.0 mass%, based on the total amount (100 mass%) of the refrigerant oil composition.

[0148] (an antioxidant) The antioxidant is preferably one or more selected from the group consisting of a phenol-based antioxidant and an amine-based antioxidant.

[0149] As the phenol-based antioxidant, 2,6-di-tert-butyl-4-methylphenol (DBPC), 2,6-di-tert-butyl-4-ethylphenol, 2,2'-methylenebis(4-methyl-6-tert-butylphenol), and the like can be exemplified.

[0150] As the amine-based antioxidant, phenyl-α-naphthylamine, N,N'-diphenyl-p-phenylenediamine, and the like can be exemplified.

[0151] Among these, 2,6-di-tert-butyl-4-methylphenol (DBPC) is more preferable.

[0152] From the viewpoint of stability and antioxidant performance, the content of the antioxidant is preferably 0.01 to 5.0 mass%, more preferably 0.05 to 3.0 mass%, and further preferably 0.10 to 1.50 mass%, based on the total amount (100 mass%) of the refrigerant oil composition.

[0153] (an oiliness improver) As the oiliness improver, aliphatic saturated or unsaturated monocarboxylic acids such as stearic acid and oleic acid; polymeric 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 lauryl amide and oleyl amide; partial esters of polyhydric alcohols such as glycerol and sorbitol with aliphatic saturated or unsaturated monocarboxylic acids, and the like can be exemplified.

[0154] (Oxygen trapping agent) As the oxygen trapping agent, aliphatic unsaturated compounds, terpenes having a double bond, and the like can be exemplified.

[0155] As the aliphatic unsaturated compound, an unsaturated hydrocarbon is preferred, and specifically, alkenes; polyenes such as dienes and trienes, and the like can be exemplified. As the alkenes, from the viewpoint of reactivity with oxygen, a-olefins such as 1-tetradecene, 1-hexadecene, and 1-octadecene are preferred.

[0156] As the aliphatic unsaturated compound other than the above, from the viewpoint of reactivity with oxygen, unsaturated aliphatic alcohols having a conjugated double bond represented by the formula C 20 H 30 O such as vitamin A ((2E, 4E, 6E, 8E)-3, 7-dimethyl-9-(2, 6, 6-trimethylcyclohexen-l-yl) nona-2, 4, 6, 8-tetraen-l-ol) are preferred.

[0157] As the terpene having a double bond, a terpene hydrocarbon having a double bond is preferred, and from the viewpoint of reactivity with oxygen, a-farnesene (C 15 H 24 : 3, 7, 11-trimethyldodeca-l, 3, 6, 10-tetraene) and β-farnesene (C 15 H 24 : 7, 11-dimethyl-3-methylidenedodeca-l, 6, 10-triene) are more preferred.

[0158] (Acid trapping agent) As the acid trapping agent, epoxy compounds such as phenyl glycidyl ether, alkyl glycidyl ether, alkylene glycol glycidyl ether, epoxycyclohexane, epoxy a-alkane, and epoxidized soybean oil can be exemplified, and at least one selected from the group consisting of glycidyl ester, glycidyl ether, and epoxy a-alkane is particularly suitable as the acid trapping agent.

[0159] As the glycidyl ether, glycidyl ethers derived from linear, branched, cyclic saturated or unsaturated aliphatic monohydric or polyhydric alcohol having usually 3 to 30, preferably 4 to 24, more preferably 6 to 16 carbon atoms, or aromatic compounds having one or more hydroxyl groups can be exemplified. In the case of aliphatic polyhydric alcohol, aromatic compounds having two or more hydroxyl groups, in order to stabilize the refrigerant oil composition, from the viewpoint of inhibiting the increase in hydroxyl value, it is preferable that all the hydroxyl groups are glycidyl etherified.

[0160] Among these, glycidyl ethers derived from linear, branched, cyclic saturated aliphatic monohydric alcohol having 6 to 16 carbon atoms are particularly preferable. As such glycidyl ethers, 2-ethyl ethyl glycidyl ether, 2-ethyl hexyl glycidyl ether, isononyl glycidyl ether, octanoyl glycidyl ether, lauryl glycidyl ether, myristyl glycidyl ether, and the like can be exemplified.

[0161] On the other hand, as the epoxy a-alkane, a substance having usually 4 to 50, preferably 4 to 24, more preferably 6 to 16 carbon atoms can be used.

[0162] The acid scavenger can be used alone or in combination with two or more kinds.

[0163] The content of the acid scavenger is preferably 0.01 to 5.0% by mass, more preferably 0.05 to 3.0% by mass, further preferably 0.10 to 2.0% by mass, based on the total amount (100% by mass) of the refrigerant oil composition.

[0164] (Copper deactivator) As the copper deactivator, N-[N,N'-dialkyl (alkyl group having 3 to 12 carbon atoms) aminomethyl] triazole and the like can be exemplified.

[0165] (Antirust agent) As the antirust agent, metal sulfonates, aliphatic amines, organic phosphites, organic phosphates, organic sulfonate metal salts, organic phosphate metal salts, alkenyl succinates, polyol esters, and the like can be exemplified.

[0166] (Antifoaming agent) As the antifoaming agent, organosilicon-based antifoaming agents such as silicone oil, fluorinated silicone oil, and the like can be exemplified.

[0167] (Viscosity index improver) As the viscosity index improver, polymethacrylates, polyisobutylenes, ethylene-propylene copolymers, styrene-diene hydrogenated copolymers, and the like can be exemplified.

[0168] (E.P. agent other than component (B)) As the extreme pressure agent other than component (B), a phosphorus-based extreme pressure agent, a metal salt of a carboxylic acid, a sulfur-based extreme pressure agent, and the like can be exemplified.

[0169] As the phosphorus-based extreme pressure agent other than component (B), phosphoric acid ester, acid phosphoric acid ester, phosphorous acid ester, acid phosphorous acid ester, amine salts thereof, and the like can be exemplified. Specifically, trimethylphenyl phosphate (TCP), triphenyl phosphate, tris(nonylphenyl)phosphite, dioctyl hydrogen phosphite, 2-ethylhexyl diphenyl phosphite, and the like can be exemplified.

[0170] As the metal salt of a carboxylic acid, a metal salt of a carboxylic acid having a carbon number of 3 to 60 (preferably 3 to 30), and the like can be exemplified. Among these, one or more selected from metal salts of a fatty acid having a carbon number of 12 to 30 and a dicarboxylic acid having a carbon number of 3 to 30 are preferred. As the metal constituting the metal salt, alkali metals and alkaline earth metals are preferred, and alkali metals are more preferred.

[0171] As the sulfur-based extreme pressure agent, sulfurized oils, sulfurized fatty acids, sulfurized esters, sulfurized olefins, dialkyl polysulfides, thio carbamic acid esters, thio terpenes, thiodipropionic acid dialkyl esters, and the like can be exemplified.

[0172] The refrigerant oil composition of the present embodiment contains component (B) as an extreme pressure agent, and therefore, can not contain an extreme pressure agent other than component (B).

[0173] When the refrigerant oil composition of the present embodiment contains an extreme pressure agent other than component (B), the content thereof is preferably 1% by mass or less, more preferably 0.5% by mass or less, and further preferably 0.1% by mass or less, based on the total amount (100% by mass) of the refrigerant oil composition, from the viewpoint of lubricity and stability.

[0174] In addition, from the viewpoint of improving corrosion resistance, the content of the dithiophosphoric acid ester in the refrigerant oil composition of the present embodiment is preferably 1% by mass or less, more preferably 0.5% by mass or less, and further preferably 0.1% by mass or less, and most preferably contains none, based on the total amount (100% by mass) of the refrigerant oil composition.

[0175] <Use of the refrigerant oil composition> More specifically, the refrigerant oil composition of the present embodiment is used for a refrigerant having a refrigeration cycle including, as necessary, a compressor, a condenser, an expansion mechanism (expansion valve or the like), and an evaporator, or including, as necessary, a compressor, a condenser, an expansion mechanism, a drier, and an evaporator. The refrigerant oil composition of the present embodiment is preferably used for lubricating, for example, a sliding portion provided in a compressor or the like.

[0176] Therefore, the present invention also provides a lubrication method using the refrigerator oil composition of this embodiment in a lubricated portion inside a refrigerator.

[0177] Furthermore, the refrigerating machine oil composition of the present embodiment can be used in, for example, air conditioners, refrigerators, vending machines, display cases, refrigeration systems, water heating systems, or heating systems.

[0178] Examples of the air conditioner include open-type car air conditioners, electric vehicle air conditioners, and other car air conditioners; and gas heat pump (GHP) air conditioners.

[0179] [Refrigerator composition] The composition for refrigerators according to the present embodiment is a composition for refrigerators comprising the refrigerator oil composition according to the present embodiment and a refrigerant.

[0180] <Refrigerant> Examples of the refrigerant include fluorocarbon refrigerants such as unsaturated fluorocarbon compounds and saturated fluorocarbon compounds; and natural refrigerants such as hydrocarbon refrigerants, carbon dioxide, and ammonia. These refrigerants may be used alone or in combination of two or more. Among these, the refrigerant preferably contains one or more selected from the group consisting of unsaturated fluorocarbon compounds, saturated fluorocarbon compounds, hydrocarbon hydrogen, carbon dioxide, and ammonia, and more preferably contains an unsaturated fluorocarbon compound.

[0181] Hereinafter, each refrigerant will be described.

[0182] <Unsaturated fluorinated hydrocarbon compounds> Unsaturated fluorocarbon compounds have low thermal stability at high temperatures. Therefore, when used as refrigerants, they generate acidic substances such as hydrogen fluoride (HF), resulting in a disadvantageous tendency for the acid value to increase. The use of the refrigeration oil composition of this embodiment eliminates this disadvantage of unsaturated fluorocarbon compounds, ensuring the stability of refrigeration systems, etc., that use unsaturated fluorocarbon compounds as refrigerants. Furthermore, the refrigeration oil composition of this embodiment exhibits particularly excellent wear resistance and seizure resistance when combined with fluorocarbon refrigerants (particularly unsaturated fluorocarbon refrigerants).

[0183] Therefore, in the composition for refrigerators according to the present embodiment, the refrigerant is preferably a refrigerant containing an unsaturated fluorinated hydrocarbon compound (HFO).

[0184] The content of the unsaturated fluorinated hydrocarbon compound (HFO) in the refrigerant is preferably 50% by mass or more, more preferably 70% by mass or more, and even more preferably 90% by mass or more, based on the total amount of the refrigerant (100% by mass). The refrigerant is even more preferably a refrigerant consisting solely of the unsaturated fluorinated hydrocarbon compound (HFO).

[0185] As the unsaturated fluorinated hydrocarbon compound, mention can be made of a straight-chain or branched-chain alkenes having 2 to 6 carbon atoms, fluorides of cyclic alkenes having 4 or more and 6 or less carbon atoms, and the like, which have a carbon-carbon double bond.

[0186] More specifically, mention can be made of ethylene into which 1 to 3 fluorine atoms are introduced, propylene into which 1 to 5 fluorine atoms are introduced, butene into which 1 to 7 fluorine atoms are introduced, pentene into which 1 to 9 fluorine atoms are introduced, hexene into which 1 to 11 fluorine atoms are introduced, cyclobutene into which 1 to 5 fluorine atoms are introduced, cyclopentene into which 1 to 7 fluorine atoms are introduced, cyclohexene into which 1 to 9 fluorine atoms are introduced, and the like.

[0187] Among these unsaturated fluorinated hydrocarbon compounds, preference is given to fluorides of propylene, more preferably propylene into which 3 to 5 fluorine atoms are introduced, and further preferably propylene into which 4 fluorine atoms are introduced. Specifically, as the preferred compound, mention can be made of 1,3,3,3-tetrafluoropropene (R1234ze), 2,3,3,3-tetrafluoropropene (R1234yf), and the like.

[0188] These unsaturated fluorinated hydrocarbon compounds can be used singly, or two or more kinds thereof can be used in combination, or can be used in combination with a refrigerant other than the unsaturated fluorinated hydrocarbon compound. Here, as an example of the use in combination with a refrigerant other than the unsaturated fluorinated hydrocarbon compound, mention can be made of a mixed refrigerant of a saturated fluorinated hydrocarbon compound and an unsaturated fluorinated hydrocarbon compound. As the mixed refrigerant, mention can be made of a mixed refrigerant of R32 and R1234yf, a mixed refrigerant of R32 and R1234ze and R152a (AC5, mixed ratio: 13.23:76.20:9.96), and the like.

[0189] As the saturated fluorinated hydrocarbon compound, preference is given to fluorides of alkanes having 1 to 4 carbon atoms, more preferably fluorides of alkanes having 1 to 3 carbon atoms, and further preferably fluorides of alkanes having 1 or 2 carbon atoms (methane or ethane). As the fluorides of methane or ethane, mention can be made of 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 which preference is given to difluoromethane and 1,1,1,2,2-pentafluoroethane.

[0190] These saturated fluorinated hydrocarbon compounds can be used alone or in combination of two or more. As an example of the combination of two or more, a mixed refrigerant in which two or more kinds of saturated fluorinated hydrocarbon compounds having 1 or more and 3 or less carbon atoms are mixed, and a mixed refrigerant in which two or more kinds of saturated fluorinated hydrocarbon compounds having 1 or more and 2 or less carbon atoms are mixed can be given.

[0191] As the mixed refrigerant, a mixture of R32 and R125 (R410A), a mixture of R125 and R143a and R134a (R404A), a mixture of R32 and R125 and R134a (R407A, R407C, R407E, etc.), a mixture of R125 and R143a (R507A), and the like can be given.

[0192] <Natural refrigerant> As the natural refrigerant, one or more kinds selected from a hydrocarbon refrigerant (HC), carbon dioxide (CO2), and ammonia, and preferably a hydrocarbon refrigerant can be given. One of them can be used alone, or two or more can be used in combination, or can be combined with a refrigerant other than the natural refrigerant. As an example of the combination with a refrigerant other than the natural refrigerant, a mixed refrigerant with a saturated fluorinated hydrocarbon compound and / or an unsaturated fluorinated hydrocarbon compound can be given. As a specific mixed refrigerant, a mixed refrigerant of carbon dioxide and R1234ze and R134a (AC6, compounding ratio 5.15:79.02:15.41), and the like can be given.

[0193] As the hydrocarbon refrigerant, a hydrocarbon having 1 to 8 carbon atoms is preferred, a hydrocarbon having 1 to 5 carbon atoms is more preferred, and a hydrocarbon having 3 to 5 carbon atoms is further preferred. If the number of carbon atoms is 8 or less, the boiling point of the refrigerant does not become too high, and it is preferred as a refrigerant. As the hydrocarbon refrigerant, methane, ethane, ethylene, propane (R290), cyclopropane, propylene, n-butane, isobutane (R600a), 2-methylbutane, n-pentane, isopentane, cyclopentane isobutane, n-butane, and the like can be given.

[0194] The hydrocarbon refrigerant can be used alone or in combination of two or more. In addition, the hydrocarbon refrigerant can be used alone as a hydrocarbon refrigerant, or as a mixed refrigerant in which a hydrocarbon refrigerant is mixed with a fluorinated hydrocarbon refrigerant such as R134a, a refrigerant other than the hydrocarbon refrigerant such as carbon dioxide.

[0195] The composition for a refrigerator of the present embodiment preferably has a mass ratio of the refrigerant to the refrigerant oil composition of 1 / 99 to 90 / 10, more preferably 5 / 95 to 70 / 30. If the mass ratio of the refrigerant oil composition to the refrigerant is set to be within this range, lubricity and suitable refrigerating capacity in a refrigerator can be obtained.

[0196] The composition for a refrigerator of the present embodiment is preferably used in, for example, an air conditioner, a refrigerator, a vending machine, a display case, a refrigeration system, a hot water system, or a heating system. Note that as an air conditioner, a car air conditioner such as an open-type car air conditioner or an electric car air conditioner, a gas heat pump (GHP) air conditioner, and the like can be given. Examples

[0197] The present application will be specifically described below by way of examples. However, the present application is not limited to the following examples.

[0198] The following shows the types of each component used to prepare the refrigerant oil compositions of the examples and comparative examples.

[0199] (1) Base oil A polyalkylene glycol (PAG) having a kinematic viscosity at 40°C of 47.0 mm 2 / s was used as the base oil.

[0200] Note that the kinematic viscosity at 40°C was measured in accordance with JIS K2283:2000 using a glass capillary viscometer.

[0201] (2) Component (B) • Phosphonate 1: dimethyl stearyl phosphonate (manufactured by SOLVAY, DURAPHOS 100) • Phosphonate 2: diethyl stearyl phosphonate (manufactured by JOSCHI KAGAKU CO., LTD., JC-390) • Phosphonate 3: diethyl-3,5-di-tert-butyl-4-hydroxybenzyl phosphonate (manufactured by JOSCHI KAGAKU CO., LTD., JC-356).

[0202] (3) Comparative extreme pressure agent (component (B')) • Phosphonate 1': diethyl phenyl phosphonate (manufactured by JOSCHI KAGAKU CO., LTD., DEPP) • Phosphonate 2': diethyl-4-methylbenzyl phosphonate (manufactured by JOSCHI KAGAKU CO., LTD., JC-243) • TCP: tricresyl phosphate.

[0203] (4) Phenol-based antioxidant • DBPC: 2,6-di-tert-butyl-4-methylphenol.

[0204] (5) Acid scavenger • Epoxy-based acid scavenger: 2-ethylhexyl glycidyl ether.

[0205] (6) Refrigerant • R1234yf: 2,3,3,3-tetrafluoropropene.

[0206] Hereinafter, structural formulas of the above-mentioned component (B) and component (B') are shown.

[0207] [Chemical Formula 13] .

[0208] [Examples 1 to 3 and Comparative Examples 1 to 3] A refrigeration oil composition having the composition shown in Table 1 was prepared, and the wear resistance, seizure resistance, and thermal stability were evaluated by the methods described below. The evaluation results are shown in Table 1.

[0209] In addition, the compounding amounts of the component (B) and component (B') in each refrigeration oil composition were unified to an amount in which the phosphorus atom content was 840 mass ppm based on the total amount of the composition.

[0210] [Phosphorus atom content] The content of the phosphorus atom was measured in accordance with JPI-5S-38-03.

[0211] [FALEX test] (1) As the pin and block, the following objects were prepared. • Pin: SAE3135 • Block: AISIC1137.

[0212] (2) Wear amount measurement Using a closed-type Falex tester, the following test was performed in accordance with ASTM D2670.

[0213] The pin and block were set in the closed-type Falex tester, 280 g of the refrigeration oil composition to be evaluated was introduced into the test container, after temporary pressure reduction, refrigerant (R1234yf) was sealed until the pressure reached 0.3 MPaG, the rotation speed was set to 290 rpm, the oil temperature was set to 50°C, the load was set to 1,779 N, and the operation was performed for 60 minutes, and the wear amount (mg) of the pin and block was measured.

[0214] (3) Seizure load measurement Using an open-type Falex tester, the following test was performed in accordance with ASTM D3233.

[0215] The pin and block were set, and the seizure load of the sample oil (refrigeration oil composition) was measured using the following conditions.

[0216] Test load: 1112 N x 1 minute Rotation speed: 290 rpm Oil temperature: room temperature.

[0217] [Thermal stability] Into a pressure vessel container (volume: 200 ml), Fe, Cu and Al as catalysts were charged, and further, a mixture of 20 g of the refrigerant oil composition obtained in each example and 20 g of refrigerant (R1234yf) was filled, while moisture of 2,000 mass ppm was filled, and after keeping at 175°C for 336 hours, evaluation of acid value (mgKOH / g) was performed.

[0218] The acid value was measured according to JIS K2501 by indicator photometric titration method (refer to Annex 1 in the aforementioned JIS standard).

[0219] [Table 1] .

[0220] According to Table 1, the refrigerant oil compositions of Examples 1 to 3 obtained using component (B) had less abrasion amount, high seizure load, and the value of acid value after the thermal stability test was also suppressed to be low.

[0221] On the other hand, in Comparative Example 1, R 3 in the general formula (1) of phosphonate 1' used was a phenyl group, and in Comparative Example 2, R 3 in phosphonate 2' used was a methylbenzyl group, and the number of carbon atoms was not 9 or more in either case, and as a result, the refrigerant oil compositions obtained had large abrasion amount and insufficient seizure load. Further, the refrigerant oil composition of Comparative Example 3 obtained using TCP had large abrasion amount, insufficient seizure load, and also had large acid value after the thermal stability test.

[0222] From the above results, it was known that the refrigerant oil composition of the present embodiment was excellent in abrasion resistance and seizure resistance, and also excellent in thermal stability.

[0223] Industrial applicability The refrigerant oil composition of the present embodiment is excellent in abrasion resistance, seizure resistance and thermal stability. Thus, it can be suitably used, for example, in automotive air conditioners such as open-type automotive air conditioners and electric automotive air conditioners, air conditioners such as indoor air conditioners and container air conditioners, gas heat pumps (GHP), refrigeration systems such as cold storage, refrigerators, vending machines and display cases, hot water systems such as water heaters and floor heating, and heating systems.

Claims

1. A refrigerant oil composition comprising a base oil (A) and a phosphonate (B) represented by the following general formula (1), [Chemical Formula 1] wherein R 1 and R 2 each independently represents a hydrocarbon group having 1 to 8 carbon atoms; R 3 represents a hydrocarbon group having 9 to 40 carbon atoms optionally having a hydroxyl group as a substituent.

2. The refrigerant oil composition according to claim 1, wherein, The content of the phosphonate (B) is 200 to 4000 mass ppm in terms of phosphorus atoms based on the total amount of the refrigerant oil composition.

3. The refrigerant oil composition according to claim 1 or 2, wherein, In the general formula (1), R 1 and R 2 each independently represent an alkyl group having 1 to 4 carbon atoms or an alkenyl group having 2 to 4 carbon atoms; R 3 represents a hydrocarbon group having 12 to 30 carbon atoms optionally having a hydroxyl group as a substituent.

4. The refrigerant oil composition according to any one of claims 1 to 3, wherein, In the general formula (1), R 3 represents a linear or branched alkyl group or alkenyl group having 14 to 24 carbon atoms, or a group represented by the following general formula (2), [Chemical Formula 2] In the formula, L 1 represents a single bond, -CH2- or -CH2CH2-; R 4 and R 5 each independently represents a hydrocarbon group having 2 to 10 carbon atoms.

5. The refrigeration compressor oil composition of any of claims 1-4, wherein, The base oil (A) comprises one or more selected from the group consisting of polyalkylene glycol (PAG), polyvinyl ether (PVE), polyol ester (POE), and mineral oil.

6. The refrigerant oil composition according to any one of claims 1 to 5, further comprising an antioxidant (C).

7. The refrigerant oil composition according to any one of claims 1 to 6, further comprising an acid scavenger (D).

8. The refrigerant oil composition according to any one of claims 1 to 7, further comprising one or more selected from the group consisting of an oiliness improver, a copper deactivator, an antirust agent, an antifoaming agent, and a viscosity index improver.

9. A refrigerant composition comprising the refrigerant oil composition according to any one of claims 1 to 8 and a refrigerant.

10. The composition for a refrigerator according to claim 9, wherein, The refrigerant comprises one or more selected from the group consisting of unsaturated fluorinated hydrocarbon refrigerant, saturated fluorinated hydrocarbon refrigerant, hydrocarbon-based refrigerant, carbon dioxide, and ammonia.

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

12. A method for producing a refrigerant oil composition, comprising a step of mixing a base oil (A) and a phosphonate (B) represented by the following general formula (1), [Chemical Formula 3] wherein R 1 and R 2 each independently represents a hydrocarbon group having 1 to 8 carbon atoms; R 3 represents a hydrocarbon group having 9 to 40 carbon atoms optionally having a hydroxyl group as a substituent.

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