Refrigerating machine oil composition and refrigerating machine use mixed composition

Abstract

The present invention addresses the problem of providing a refrigerator mixture composition and a refrigerator oil composition having excellent wear resistance. Further, said problem is solved by using a refrigerator oil composition that contains a base oil (A) and a phosphite (B) containing at least one selected from the group consisting of a first phosphite (B1) and a second phosphite (B2) each having a specific structure. Furthermore, said problem is solved by using a refrigerator mixture composition that contains the refrigerator oil composition and a refrigerant.

Description

[Technical field]

[0001] The present invention relates to a refrigerating machine oil composition and a mixed composition for a refrigerating machine. In this specification, the term "mixture composition for a refrigerator" refers to a composition obtained by mixing a "refrigerant" with a "refrigerating machine oil composition." [Background technology]

[0002] In recent years, with the increase in speed, pressure, and size of industrial machinery, machine elements such as compressors, hydraulic machines, turbines, gear elements, and bearings are being operated under more severe conditions. Lubricating oil compositions used in these machines are required to have lubricating performance that can sufficiently guarantee the machine life over a long period of time even under severe conditions.

[0003] Meanwhile, various additives are blended into lubricating oil compositions for the purpose of improving lubrication performance. Among them, tricresyl phosphate (hereinafter also referred to as "TCP") has been conventionally used as an additive for improving wear resistance. For example, Patent Document 1 discloses a lubricating oil reinforcer in which a predetermined amount of TCP is blended as a phosphorus-based extreme pressure agent in a base oil consisting of a mineral oil, a synthetic oil, or a mixture of these. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Application Publication No. 11-100586 Summary of the Invention [Problem to be solved by the invention]

[0005] In recent years, there has been a demand for refrigerating machine oil compositions with lubricating properties that can sufficiently guarantee machine life over a long period of time under more severe conditions than before, and therefore there is a demand for refrigerating machine oil compositions with more excellent wear resistance than before. However, as a result of extensive research conducted by the present inventors, it was found that a refrigerator oil composition containing a phosphate ester such as TCP cannot meet the above requirements.

[0006] The present invention has been made in consideration of the above-mentioned demands, and an object of the present invention is to provide a refrigerating machine oil composition and a mixed composition for a refrigerating machine which have excellent anti-wear properties. [Means for solving the problem]

[0007] As a result of extensive investigations, the present inventors have found that a refrigerating machine oil composition containing a base oil and a specific phosphite can solve the above problems, and have completed the present invention.

[0008] That is, the present invention relates to the following [1] to [3]. [1] A composition comprising a base oil (A) and a first phosphorus compound (B), The first phosphorus compound (B) is at least one selected from the group consisting of a first phosphite (B1) represented by the following general formula (1) and a second phosphite (B2) represented by the following general formula (2): [ka] [In the above general formula (1), R 11 R is an aromatic group represented by the following general formula (1a). 12 is an aliphatic hydrocarbon group having 6 to 20 carbon atoms. n is an integer of 1 to 3. When n is 2 or more, multiple R 11 -O- may be the same or different. When n=1, a plurality of -OR 12 may be the same or different from each other. [ka] [In the above general formula (1a), R 13 is a branched aliphatic hydrocarbon group having 3 to 20 carbon atoms. m is an integer of 0 to 5. When m is 2 or more, multiple R 13may be the same or different from each other. 11 This indicates the bond position with the oxygen atom in -O-. [ka] [In the above general formula (2), R 21 and R 22 are each independently an aliphatic hydrocarbon group having 10 to 30 carbon atoms.] [2] A method for producing a composite oil, comprising the steps of: mixing a base oil (A) with a first phosphorus-based compound (B); The method for producing a refrigerating machine oil composition, wherein the first phosphorus compound (B) is at least one selected from the group consisting of a first phosphite (B1) represented by the following general formula (1) and a second phosphite (B2) represented by the following general formula (2): [ka] [In the above general formula (1), R 11 R is an aromatic group represented by the following general formula (1a). 12 is an aliphatic hydrocarbon group having 6 to 20 carbon atoms. n is an integer of 1 to 3. When n is 2 or more, multiple R 11 -O- may be the same or different. When n=1, a plurality of -OR 12 may be the same or different from each other. [ka] [In the above general formula (1a), R 13 is a branched aliphatic hydrocarbon group having 3 to 20 carbon atoms. m is an integer of 0 to 5. When m is 2 or more, multiple R 13 may be the same or different from each other. 11 This indicates the bond position with the oxygen atom in -O-. [ka] [In the above general formula (2), R21 and R 22 are each independently an aliphatic hydrocarbon group having 10 to 30 carbon atoms.] [3] A mixed composition for a refrigerator, comprising the refrigerator oil composition according to [1] and a refrigerant. Effect of the Invention

[0009] According to the present invention, it is possible to provide a refrigerating machine oil composition and a mixed composition for a refrigerating machine having excellent anti-wear properties. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0010] In this specification, the lower limit and upper limit described in stages for the preferred numerical range (e.g., the range of the content, etc.) can be independently combined. For example, the description "preferably 10 to 90, more preferably 30 to 60" can be combined with the "preferable lower limit (10)" and the "more preferable upper limit (60)" to form "10 to 60." Furthermore, unless otherwise specified, a numerical range of "lower limit value to upper limit value" described in this specification means not less than the lower limit value and not more than the upper limit value. In this specification, the numerical values ​​in the examples are numerical values ​​that can be used as upper or lower limits.

[0011] In this specification, unless otherwise specified, the term "hydrocarbon group" refers to a group composed only of carbon atoms and hydrogen atoms. The term "hydrocarbon group" also includes "aliphatic groups" composed of saturated or unsaturated straight chains or saturated or unsaturated branched chains, "alicyclic groups" having one or more saturated or unsaturated carbon rings that do not have aromaticity, and "aromatic groups" having one or more aromatic rings that exhibit aromaticity, such as a benzene ring. In addition, in this specification, the term "number of ring carbon atoms" refers to the number of carbon atoms among the atoms constituting the ring itself of a compound having a structure in which atoms are bonded in a ring. When the ring is substituted with a substituent, the carbon atoms contained in the substituent are not included in the number of ring carbon atoms. The number of ring atoms refers to the number of atoms constituting the ring itself in a compound having a structure in which atoms are bonded in a ring, and does not include atoms not constituting the ring (e.g., hydrogen atoms terminating bonds of atoms constituting the ring) and atoms contained in the substituent when the ring is substituted with a substituent. In this specification, the "number of carbon atoms a to b" in the expression "a substituted or unsubstituted X group having a carbon number of a to b" represents the number of carbon atoms when the X group is unsubstituted, and does not include the number of carbon atoms of the substituent when the X group is substituted.

[0012] In this specification, "kinematic viscosity at 40°C" is also referred to as "40°C kinematic viscosity."

[0013] [Embodiments of the refrigerating machine oil composition of the present invention] The refrigerator oil composition of the present invention contains a base oil (A) and a first phosphorus-based compound (B). The first phosphorus compound (B) is at least one selected from the group consisting of a first phosphite (B1) represented by the following general formula (1) and a second phosphite (B2) represented by the following general formula (2).

[0014] [ka] [In the above general formula (1), R 11 R is an aromatic group represented by the following general formula (1a). 12 is an aliphatic hydrocarbon group having 6 to 20 carbon atoms. n is an integer of 1 to 3. When n is 2 or more, multiple R 11 -O- may be the same or different. When n=1, a plurality of -OR 12 may be the same or different from each other.

[0015] [ka] [In the above general formula (1a), R 13is a branched aliphatic hydrocarbon group having 3 to 20 carbon atoms. m is an integer of 0 to 5. When m is 2 or more, multiple R 13 may be the same or different from each other. 11 This indicates the bond position with the oxygen atom in -O-.

[0016] [ka] [In the above general formula (2), R 21 and R 22 are each independently a linear or branched aliphatic hydrocarbon group having 10 to 30 carbon atoms.]

[0017] In order to meet recent demands for refrigerator oil compositions, the present inventors have conducted extensive research into additives capable of improving the anti-wear properties of refrigerator oil compositions even under conditions that are more severe than before. First, we investigated TCP, which has been used as an additive to improve wear resistance, and found that it did not provide sufficient wear resistance improvement. Next, we investigated triphenylphosphine oxide (hereinafter also referred to as "TPPO"), and found that it did not provide sufficient wear resistance improvement, just like TCP. From these results, we thought that if phosphate esters such as TCP or organic phosphine oxide compounds such as TPPO were used, sufficient wear resistance improvement would not be obtained. As a result of further intensive research, the present inventors have found that the primary phosphite (B1) represented by the above general formula (1) and the secondary phosphite (B2) represented by the above general formula (2) exhibit a remarkable effect of improving abrasion resistance. After further extensive research, the present inventors have completed the present invention.

[0018] In the following description, the "base oil (A)" and the "first phosphorus-based compound (B)" will also be referred to as the "component (A)" and the "component (B)", respectively. In addition, the first phosphite (B1) represented by the above general formula (1) and the second phosphite (B2) represented by the above general formula (2) are also referred to as "component (B1)" and "component (B2)", respectively.

[0019] The refrigerating machine oil composition of one embodiment of the present invention may be composed only of component (A) and component (B), but may also contain components other than component (A) and component (B) as long as the effects of the present invention are not impaired. In the refrigerating machine oil composition of one embodiment of the present invention, the total content of component (A) and component (B) is preferably 80 mass% to 100 mass%, more preferably 85 mass% to 100 mass%, and even more preferably 90 mass% to 100 mass%, based on the total amount (100 mass%) of the refrigerating machine oil composition.

[0020] Each component contained in the refrigerator oil composition of the present invention will be described in detail below.

[0021] <Base oil (A)> The refrigerator oil composition of the present invention contains a base oil (A). In the refrigerator oil composition according to one embodiment of the present invention, the content of the base oil (A) is preferably 85.0 mass% or more, more preferably 90.0 mass% or more, and even more preferably 95.0 mass% or more based on the total amount (100 mass%) of the refrigerator oil composition. Also, it is preferably 99.5 mass% or less, more preferably 99.3 mass% or less, even more preferably 99.2 mass% or less, still more preferably 99.1 mass% or less, and even more preferably 99.0 mass% or less.

[0022] As the base oil (A), any base oil commonly used in refrigerating machine oil compositions can be used without particular limitation. For example, as the base oil (A), one or more oils selected from the group consisting of synthetic oils and mineral oils can be used. Here, in the refrigerating machine oil composition of one embodiment of the present invention, from the viewpoint of improving the thermal stability of the refrigerating machine oil composition, the base oil (A) is preferably one or more base oils selected from the group consisting of polyalkylene glycols (hereinafter also referred to as "PAG"), polyvinyl ethers (hereinafter also referred to as "PVE"), poly(oxy)alkylene glycol or a copolymer of its monoether and polyvinyl ether (hereinafter also referred to as "ECP"), polyol esters (hereinafter also referred to as "POE"), and mineral oils (hereinafter also referred to as "base oil (A1)"). From the viewpoint of improving compatibility with the refrigerant, improving hydrolysis resistance, and improving the thermal stability of the refrigerating machine oil composition, it is more preferable to include one or more base oils selected from the group consisting of PVE and PAG (hereinafter also referred to as "base oil (A2)"). In a further preferred embodiment, base oil (A) contains PVE (hereinafter also referred to as "base oil (A3)") or PAG (hereinafter also referred to as "base oil (A4)"). From the viewpoint of making it easier to exert the wear resistance improving effect, it is even more preferable that base oil (A) contains PAG (hereinafter also referred to as "base oil (A4)"). PVE, PAG, ECP, POE, and mineral oil are described in detail below.

[0023] (Polyvinyl ethers (PVE)) The PVE may be any polymer having one or more structural units derived from vinyl ether. When the base oil (A) contains a PVE, the PVE may be used alone or in combination of two or more kinds. From the viewpoint of compatibility with the refrigerant, the PVE is preferably a polymer having one or more structural units derived from vinyl ether and having an alkyl group having 1 to 4 carbon atoms in the side chain. From the viewpoint of further improving compatibility with the refrigerant, the alkyl group is preferably a methyl group or an ethyl group, and more preferably a methyl group.

[0024] The PVE is preferably a polymer (A-1) having one or more structural units represented by the following general formula (A-1).

[0025] [ka]

[0026] In formula (A-1), R 1a , R 2a , and R 3a R each independently represents a hydrogen atom or a hydrocarbon group having 1 to 8 carbon atoms. 4a R 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 of the formula (A-1) is usually 0 to 10, preferably 0 to 5, more preferably 0 to 3, and even more preferably 0. 4a If multiple exists, multiple OR 4a may be the same or different from each other.

[0027] R 1a , R 2a and R 3a Examples of the hydrocarbon group having 1 to 8 carbon atoms represented by the formula (I) 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; and arylalkyl groups such as benzyl group, various phenylethyl groups, and various methylbenzyl groups. Here, "various types" refers to "linear, branched, or cyclic" hydrocarbon groups, and for example, "various butyl groups" refers to various butyl groups such as "n-butyl group, sec-butyl group, isobutyl group, tert-butyl group, cyclobutyl group, etc. In addition, for groups having a cyclic structure, this indicates that positional isomers such as ortho-, meta-, and para-isomers are included, and the same applies hereinafter.

[0028] R 1a , R 2a, and R 3a The hydrocarbon group represented by the following formula (1) preferably has 1 to 6 carbon atoms, and more preferably 1 to 3 carbon atoms. R 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.

[0029] R 4a Examples of the divalent hydrocarbon group having 2 to 10 carbon atoms represented by the formula (I) include divalent aliphatic groups such as ethylene group, 1,2-propylene group, 1,3-propylene group, various butylene groups, various pentylene groups, various hexylene groups, various heptylene groups, various octylene groups, various nonylene groups, and various decylene groups; divalent alicyclic groups such as cyclohexane, methylcyclohexane, ethylcyclohexane, dimethylcyclohexane, and propylcyclohexane; divalent aromatic groups such as various phenylene groups, various methylphenylene groups, various ethylphenylene groups, various dimethylphenylene groups, and various naphthylenes; divalent alkyl aromatic groups having monovalent bonding sites at the alkyl moiety and aromatic moiety of alkyl aromatic hydrocarbons such as toluene, xylene, and ethylbenzene; and divalent alkyl aromatic groups having a bonding site at the alkyl moiety of polyalkyl aromatic hydrocarbons such as xylene and diethylbenzene. R 4a The hydrocarbon group represented by the following formula (1) preferably has 2 to 6 carbon atoms, and more preferably 2 to 4 carbon atoms. R 4a is preferably a divalent aliphatic group having 2 to 10 carbon atoms, and more preferably a divalent aliphatic group having 2 to 4 carbon atoms.

[0030] R 5aExamples of the hydrocarbon group having 1 to 10 carbon atoms represented by the formula (I) 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. R 5a The hydrocarbon group represented by the following formula (1) preferably has 1 to 8 carbon atoms, and more preferably 1 to 6 carbon atoms. R 5a From the viewpoint of further improving compatibility with the refrigerant, the alkyl group is preferably an alkyl group having 1 to 6 carbon atoms, more preferably an alkyl group having 1 to 4 carbon atoms, further preferably a methyl group or an ethyl group, and still further preferably a methyl group.

[0031] The number of units (degree of polymerization) of the structural unit represented by the above general formula (A-1) is appropriately selected according to the kinematic viscosity required for the base oil (A). The polymer having the structural unit represented by the general formula (A-1) may be a homopolymer having only one type of the structural unit, or a copolymer having two or more types of the structural unit. When the polymer is a copolymer, the form of the copolymer is not particularly limited, and may be any of a block copolymer, a random copolymer, and a graft copolymer.

[0032] At the terminal portion of the polymer (A-1), a monovalent group derived from a saturated hydrocarbon, ether, alcohol, ketone, amide, nitrile, etc., may be introduced. Among these, it is preferable that one terminal portion of the polymer (A-1) is a group represented by the following general formula (A-1-i).

[0033] [ka]

[0034] In formula (A-1-i), * indicates the bonding position to the carbon atom in the structural unit represented by general formula (A-1) above. In formula (A-1-i), R 6a , R 7a , and R 8a each independently represents a hydrogen atom or a hydrocarbon group having 1 to 8 carbon atoms, preferably a hydrogen atom or a hydrocarbon group having 1 to 6 carbon atoms, and more preferably a hydrogen atom or an alkyl group having 1 to 3 carbon atoms. R 6a , R 7a , and R 8a As the hydrocarbon group having 1 to 8 carbon atoms represented by the formula (A-1), 1a , R 2a , and R 3a Examples of the hydrocarbon group having 1 to 8 carbon atoms represented by the following formula include the same as those listed above.

[0035] 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, and more preferably a divalent aliphatic group having 2 to 4 carbon atoms. In the above formula (A-1-i), r1 is OR 9a The number of repeating units of the formula (A-1-i) is usually 0 to 10, preferably 0 to 5, more preferably 0 to 3, and even more preferably 0. 9a If multiple exists, multiple OR 9a may be the same or different from each other. R 9a As the divalent hydrocarbon group having 2 to 10 carbon atoms represented by the formula (A-1), 4a Examples of the divalent hydrocarbon group having 2 to 10 carbon atoms and represented by the following formula include the same as those listed above.

[0036] In formula (A-1-i), R10a represents a hydrocarbon group having 1 to 10 carbon atoms, preferably a hydrocarbon group having 1 to 8 carbon atoms, and more preferably an alkyl group having 1 to 8 carbon atoms. In addition, R 10a As the alkyl group, when r1 in the above general formula (A-1-i) is 0, it is preferably an alkyl group having 1 to 6 carbon atoms, and when r1 is 1 or more, it is preferably an alkyl group having 1 to 4 carbon atoms. R 10a As the hydrocarbon group having 1 to 10 carbon atoms represented by the formula (A-1), 5a Examples of the hydrocarbon group having 1 to 10 carbon atoms and represented by the following formula include the same as those listed above.

[0037] In addition, when one end moiety of the polymer (A-1) is a group represented by the above general formula (A-1-i), the other end 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), and a group having an olefinically unsaturated bond.

[0038] [ka]

[0039] In formulas (A-1-ii) and (A-1-iii), R 6a , R 7a , R 8a , R 9a , R 10a and r1 are the same as those in the general formula (A-1-i) above. In addition, in the formula (A-1-ii), R 11a , R 12a , and r2 are each R in the above general formula (A-1-i). 9a , R 10a and the same as the provisions for r1.

[0040] In one embodiment of the present invention, the polyvinyl compound having a structural unit represented by general formula (A-1) is R 1a , R 2a , and R 3aare all hydrogen atoms, r is 0, and R 5a is an ethyl group, from the viewpoint of improving solubility in the refrigerant and thermal stability. From the same viewpoint, the polyvinyl compound having a structural unit represented by the general formula (A-1) is R 1a , R 2a , and R 3a are all hydrogen atoms, r is 0, and R 5a is an ethyl group; and polyethyl vinyl ether, R 1a , R 2a , and R 3a are all hydrogen atoms, r is 0, and R 5a is an isobutyl group. In this case, the content ratio of the structural units of ethyl vinyl ether to the structural units of isobutyl vinyl ether [(structural units of ethyl vinyl ether) / (structural units of isobutyl vinyl ether)] is preferably 50 / 50 to 99 / 1, more preferably 70 / 30 to 99 / 1, even more preferably 80 / 20 to 95 / 5, and still more preferably 85 / 15 to 95 / 5, in terms of molar ratio.

[0041] In the present invention, the above polyvinyl ether compounds may be used alone or in combination of two or more.

[0042] (Polyalkylene glycols (PAG)) The PAG is preferably a polymer (A-2) represented by the following general formula (A-2). R 13a -[(OR 14a ) p -OR 15a ] q (A-2) When the base oil (A) contains a PAG, the PAG may be used alone or in combination of two or more kinds.

[0043] In the above general formula (A-2), R 13arepresents a hydrogen atom, a monovalent hydrocarbon group having 1 to 10 carbon atoms, an acyl group having 2 to 10 carbon atoms, a divalent to hexavalent hydrocarbon group having 1 to 10 carbon atoms, or a substituted or unsubstituted heterocyclic group having 3 to 10 ring atoms; R 14a represents an alkylene group having 2 to 4 carbon atoms, 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 atoms. Examples of the substituent that the heterocyclic group may have include an alkyl group having 1 to 10 carbon atoms (preferably 1 to 6, more preferably 1 to 3); a cycloalkyl group having 3 to 10 ring carbon atoms (preferably 3 to 8, more preferably 5 or 6); an aryl group having 6 to 18 ring carbon atoms (preferably 6 to 12); a halogen atom (a fluorine atom, a chlorine atom, a bromine atom, an iodine atom); a cyano group; a nitro group; a hydroxy group; and an amino group. These substituents may be further substituted with any of the above-mentioned substituents.

[0044] q is an integer of 1 to 6, preferably an integer of 1 to 3, and more preferably 1. In addition, q is R in the above general formula (A-2). 13a For example, R 13a When R is an alkyl group or an acyl group, n is 1, and R 13a is a hydrocarbon group or a heterocyclic group which is di-, tri-, tetra-, penta-, or hexavalent, then n is 2, 3, 4, 5, or 6, respectively. p is OR 14a and is usually 1 or more, and preferably a number such that p×q is 6 to 80. The value of p is a value that is appropriately set in order to adjust the 40° C. kinematic viscosity of the base oil (A) to an appropriate range, and is not particularly limited as long as the 40° C. kinematic viscosity is adjusted to be in an appropriate range. In addition, multiple R 14a may be the same or different from each other. When q is 2 or more, multiple R 15a may be the same or different from each other.

[0045] R 13a and R 15a Examples of the monovalent hydrocarbon group represented by the formula (1) include alkyl groups such as methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, sec-butyl, tert-butyl, various pentyl groups, various hexyl groups, various heptyl groups, various octyl groups, various nonyl groups, and various decyl groups; cycloalkyl groups such as cyclopentyl, cyclohexyl, various methylcyclohexyl groups, various ethylcyclohexyl groups, various propylcyclohexyl groups, and various dimethylcyclohexyl groups; aryl groups such as phenyl, various methylphenyl groups, various ethylphenyl groups, various dimethylphenyl groups, various propylphenyl groups, various trimethylphenyl groups, various butylphenyl groups, and various naphthyl groups; arylalkyl groups such as benzyl, various phenylethyl groups, various methylbenzyl groups, various phenylpropyl groups, and various phenylbutyl groups; and the like. The alkyl groups may be either linear or branched. R 13a and R 15a From the viewpoint of compatibility with the refrigerant, the monovalent hydrocarbon group represented by the following formula (I) preferably has 1 to 10 carbon atoms, more preferably 1 to 6 carbon atoms, and even more preferably 1 to 3 carbon atoms.

[0046] R 13a and R 15a The hydrocarbon group portion of the acyl group having 2 to 10 carbon atoms represented by the following formula (I) may be linear, branched or cyclic. The alkyl group portion may be any of the above-mentioned R 13a and R 15a Among the hydrocarbon groups represented by the following formula, those having 1 to 9 carbon atoms can be mentioned. R 13a and R 15a The number of carbon atoms in the acyl group represented by the following formula is preferably 2 to 8, and more preferably 2 to 6, from the viewpoint of compatibility with the refrigerant.

[0047] R 13a The divalent to hexavalent hydrocarbon group represented by the above formula (I) is 13aand residues in which hydroxyl groups have been removed from polyhydric alcohols such as trimethylolpropane, glycerin, pentaerythritol, sorbitol, 1,2,3-trihydroxycyclohexane, and 1,3,5-trihydroxycyclohexane. R 13a The number of carbon atoms in the divalent to hexavalent acyl group represented by the following formula is preferably 2 to 10, and more preferably 2 to 6, from the viewpoint of compatibility with the refrigerant.

[0048] R 13a and R 15a The heterocyclic group represented by the following formula (I) is preferably an oxygen atom-containing heterocyclic group or a sulfur atom-containing heterocyclic group. The heterocyclic group may be a saturated ring or an unsaturated ring. Examples of the oxygen atom-containing heterocyclic group include oxygen atom-containing saturated heterocycles such as ethylene oxide, 1,3-propylene oxide, tetrahydrofuran, tetrahydropyran, and hexamethylene oxide; and residues in which 1 to 6 hydrogen atoms have been removed from oxygen atom-containing unsaturated heterocycles such as acetylene oxide, furan, pyran, oxycycloheptatriene, isobenzofuran, and isochromene. Examples of the sulfur atom-containing heterocyclic group include residues in which 1 to 6 hydrogen atoms have been removed from sulfur atom-containing saturated heterocycles such as ethylene sulfide, trimethylene sulfide, tetrahydrothiophene, tetrahydrothiopyran, and hexamethylene sulfide, and sulfur atom-containing unsaturated heterocycles such as acetylene sulfide, thiophene, thiapyran, and thiotripyridene.

[0049] R 13a and R 15a The heterocyclic group represented by the formula (A-1) may have a substituent, and the substituent may be bonded to the oxygen atom in the formula (A-2). As the substituent, as described above, 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 heterocyclic group preferably has 3 to 10 ring atoms, and more preferably 3 to 6 ring atoms, from the viewpoint of compatibility with the refrigerant.

[0050] R 14a Examples of the alkylene group represented by the formula (I) include alkylene groups having two carbon atoms, such as a dimethylene group (-CH2CH2-) and an ethylene group (-CH(CH3)-); alkylene groups having three carbon atoms, such as a trimethylene group (-CH2CH2CH2-), a propylene group (-CH(CH3)CH2-), a propylidene group (-CHCH2CH3-), and an isopropylidene group (-C(CH3)2-); and alkylene groups having four carbon atoms, such as a tetramethylene group (-CH2CH2CH2CH2-), a 1-methyltrimethylene group (-CH(CH3)CH2CH2-), a 2-methyltrimethylene group (-CH2CH(CH3)CH2-), and a butylene group (-C(CH3)2CH2-). Among these, R 14a As the alkyl group, a propylene group (-CH(CH3)CH2-) is preferable.

[0051] In the polymer (A-2) represented by the above general formula (A-2), the content of the oxypropylene unit (-OCH(CH3)CH2-) is 14a ) is preferably 50 mol % or more, more preferably 65 mol % or more, and even more preferably 80 mol % or more, based on the total amount (100 mol %) of the copolymers.

[0052] Among the polymers (A-2) represented by the above general formula (A-2), at least one 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), polyoxypropylene glycol monomethyl ether represented by the following general formula (A-2-iv), and polyoxypropylene glycol diacetate are preferred.

[0053] [ka] (In formula (A-2-i), p1 represents a number of 1 or more, and preferably a number of 6 to 80.)

[0054] [ka] (In formula (A-2-ii), p2 and p3 each independently represent a number of 1 or more, and preferably a number such that the value of p2+p3 is 6 to 80.)

[0055] [ka] (In formula (A-2-iii), p4 represents a number of 1 or more, and preferably a number of 6 to 80.)

[0056] [ka] (In formula (A-2-iv), p5 represents a number of 1 or more, and preferably a number of 6 to 80.)

[0057] In addition, p1 in the above general formula (A-2-i), p2 and p3 in the above general formula (A-2-ii), p4 in the above general formula (A-2-iii), and p5 in the above general formula (A-2-iv) may be appropriately selected according to the kinematic viscosity required for the base oil (A).

[0058] (Poly(oxy)alkylene glycol or its monoether and polyvinyl ether copolymer (ECP)) The copolymer (ECP) of poly(oxy)alkylene glycol or its monoether and polyvinyl ether may be a copolymer having a structural unit derived from poly(oxy)alkylene glycol or its monoether and a structural unit derived from polyvinyl ether. It should be noted that the term "poly(oxy)alkylene glycol" refers to both polyalkylene glycol and polyoxyalkylene glycol. When the base oil (A) contains an ECP, the ECP may be used alone or in combination of two or more kinds. Among such ECPs, copolymer (A-3-i) represented by the following general formula (A-3-i) or copolymer (A-3-ii) represented by the following general formula (A-3-ii) is preferred.

[0059] [ka]

[0060] In the general formulae (A-3-i) and (A-3-ii), R 1c , R 2c , and R 3c each independently represents a hydrogen atom or a hydrocarbon group having 1 to 8 carbon atoms. R 4c each independently represents a hydrocarbon group having 1 to 10 carbon atoms. R 5c each independently represents an alkylene group having 2 to 4 carbon atoms. R 6c each independently represents a hydrogen atom, an alkyl group having 1 to 20 carbon atoms, a substituted or unsubstituted alicyclic group having 3 to 20 ring carbon atoms, a substituted or unsubstituted aromatic group having 6 to 24 ring carbon atoms, an acyl group having 2 to 20 carbon atoms, or an oxygen-containing hydrocarbon group having 2 to 50 carbon atoms. In addition, R 1c , R 2c , R 3c , R 4c , R 5c , and R 6c When a plurality of units are present, they may be the same or different for each structural unit. X C and Y C each independently represents a hydrogen atom, a hydroxyl group, or a hydrocarbon group having 1 to 20 carbon atoms.

[0061] In the general formulae (A-3-i) and (A-3-ii), v is OR 5c The average number of units represented by the formula: OR is a number of 1 or more, and preferably a number of 1 to 50. 5c If multiple exists, multiple OR 5c may be the same or different.5c " indicates a structural unit derived from poly(oxy)alkylene glycol or its monoether. In the general formula (A-3-i), u is a number of 0 or more and preferably a number from 0 to 50, and w is a number of 1 or more and preferably a number from 1 to 50. In the general formula (A-3-ii), x and y each independently represent a number of 1 or more, and preferably a number of 1 to 50. The values ​​of v, u, w, x and y are not particularly limited as long as they are adjusted according to the hydroxyl value required for the base oil (A).

[0062] The form of copolymerization of the copolymer (A-3-i) and the copolymer (A-3-ii) is not particularly limited, and may be a block copolymer, a random copolymer, or a graft copolymer.

[0063] R 1c , R 2c , and R 3c Examples of the hydrocarbon group having 1 to 8 carbon atoms that can be selected as R 1a , R 2a , and R 3a The examples of the monovalent hydrocarbon groups having 1 to 8 carbon atoms that can be selected as the substituents are the same as those of the monovalent hydrocarbon groups having 1 to 8 carbon atoms. R 1c , R 2c , and R 3c The number of carbon atoms in the hydrocarbon group that can be selected as is preferably 1 to 8, more preferably 1 to 6, and even more preferably 1 to 3. R 1c , R 2c , and R 3c are each independently preferably a hydrogen atom or an alkyl group having 1 to 8 carbon atoms, more preferably a hydrogen atom or an alkyl group having 1 to 6 carbon atoms, and further preferably a hydrogen atom or an alkyl group having 1 to 3 carbon atoms. Also, R 1c , R 2c , and R 3c It is preferable that at least one of R is a hydrogen atom. 1c , R 2c , and R3c It is more preferable that all of are hydrogen atoms.

[0064] R 4c Examples of the hydrocarbon group having 1 to 10 carbon atoms that can be selected as R in general formula (A-1) include 5a The examples of the hydrocarbon groups include the same ones having 1 to 10 carbon atoms that can be selected as the substituent. R 4c The number of carbon atoms in the hydrocarbon group that can be selected as is preferably 1 to 8, more preferably 1 to 6, and even more preferably 1 to 4.

[0065] R 5c The alkylene group that can be selected as R 14a The alkylene groups having 2 to 4 carbon atoms can be selected as the alkylene groups, and preferably the propylene group (-CH(CH3)CH2-). In the copolymer (A-3-i) or the copolymer (A-3-ii), the content of the oxypropylene unit (-OCH(CH3)CH2-) is the same as that of the oxyalkylene (OR) unit derived from poly(oxy)alkylene glycol or its monoether in the copolymer (A-3-i) or the copolymer (A-3-ii). 5c ) is preferably 50 mol % or more and 100 mol % or less, more preferably 65 mol % or more and 100 mol % or less, and even more preferably 80 mol % or more and 100 mol % or less, based on the total amount (100 mol %) of the above.

[0066] R 6c Examples of the alkyl group having 1 to 20 carbon atoms that can be selected as the aryl group include methyl groups, ethyl groups, various propyl groups, various butyl groups, various pentyl groups, various hexyl groups, various heptyl groups, various octyl groups, various nonyl groups, and various decyl groups. The alkyl group preferably has 1 to 10 carbon atoms, more preferably 1 to 6 carbon atoms, and further preferably 1 to 3 carbon atoms.

[0067] R 6cExamples of the alicyclic group having 3 to 20 ring carbon atoms that can be selected for include a cyclopropyl group, a cyclobutyl group, a cyclopentyl group, a cyclohexyl group, a cycloheptyl group, a cyclooctyl group, a cyclononyl group, and a cyclodecyl group. The alicyclic group preferably has 3 to 10 ring carbon atoms, more preferably 3 to 8 ring carbon atoms, and further preferably 3 to 6 ring carbon atoms. The alicyclic group may have the aforementioned substituent, and the substituent is preferably an alkyl group.

[0068] R 6c Examples of the aromatic group having 6 to 24 ring carbon atoms that can be selected as the aryl group include a phenyl group, a naphthyl group, an anthracenyl group, and a phenanthryl group. The aromatic group preferably has 6 to 18 ring carbon atoms, and more preferably 6 to 12 ring carbon atoms. The aromatic group may have the aforementioned substituent, and the substituent is preferably an alkyl group.

[0069] R 6c Examples of the acyl group having 2 to 20 ring carbon atoms that can be selected as include an acetyl group, a propionyl group, a butyryl group, an isobutyryl group, a valeryl group, an isovaleryl group, a piperoyl group, a benzoyl group, and a toluoyl group. The acyl group preferably has 2-10 carbon atoms, preferably 2-8 carbon atoms, and more preferably 2-6 carbon atoms.

[0070] R 6c Examples of the oxygen-containing hydrocarbon group having 2 to 50 carbon atoms that can be selected as the aryl group include a methoxymethyl group, a methoxyethyl group, a methoxypropyl group, a 1,1-bismethoxypropyl group, a 1,2-bismethoxypropyl group, an ethoxypropyl group, a (2-methoxyethoxy)propyl group, and a (1-methyl-2-methoxy)propyl group. The carbon-containing hydrocarbon group preferably has 2-20 carbon atoms, more preferably 2-10 carbon atoms, and even more preferably 2-6 carbon atoms.

[0071] XC , Y C Examples of the hydrocarbon group having 1 to 20 carbon atoms that can be selected as the aryl group include an alkyl group having 1 to 20 carbon atoms (preferably 1 to 10, more preferably 1 to 6, and even more preferably 1 to 3), a substituted or unsubstituted cycloalkyl group having 3 to 20 ring carbon atoms (preferably 3 to 10, more preferably 3 to 8, and even more preferably 3 to 6), a substituted or unsubstituted phenyl group, a substituted or unsubstituted naphthyl group, and an arylalkyl group having 7 to 20 carbon atoms (preferably 7 to 13).

[0072] (Polyol esters (POE)) Examples of POE include esters of diols or polyols and fatty acids. When POE is contained in the base oil (A), one type of POE may be used alone, or two or more types may be used in combination. The POE is preferably an ester of a diol or a polyol having 3 to 20 hydroxyl groups and a fatty acid having 3 to 20 carbon atoms.

[0073] 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.

[0074] Examples of polyols include polyhydric alcohols such as trimethylolethane, trimethylolpropane, trimethylolbutane, di-(trimethylolpropane), tri-(trimethylolpropane), pentaerythritol, di-(pentaerythritol), tri-(pentaerythritol), glycerin, polyglycerin (a dimer to 20-mer of glycerin), 1,3,5-pentanetriol, sorbitol, sorbitan, sorbitol glycerin condensates, adonitol, arabitol, xylitol, and mannitol; sugars such as xylose, arabinose, ribose, rhamnose, glucose, fructose, galactose, mannose, sorbose, cellobiose, maltose, isomaltose, trehalose, sucrose, raffinose, gentianose, and melenitose; and partially etherified products thereof, methyl glucoside (glycoside), and the like. Among these, preferred are hindered alcohols such as neopentyl glycol, trimethylolethane, trimethylolpropane, trimethylolbutane, di-(trimethylolpropane), tri-(trimethylolpropane), pentaerythritol, di-(pentaerythritol), tri-(pentaerythritol), etc. The term "hindered alcohol" refers to an alcohol having a quaternary carbon atom bonded to four carbon atoms.

[0075] From the viewpoint of lubricating performance, the carbon number of the fatty acid is preferably 3 or more, more preferably 4 or more, even more preferably 5 or more, and still more preferably 8 or more, and from the viewpoint of compatibility with the refrigerant, the carbon number is preferably 20 or less, more preferably 16 or less, even more preferably 12 or less, and still more preferably 10 or less. The carbon number of the fatty acid includes the carbon atom of the carboxy group (-COOH) contained in the fatty acid. The fatty acid may be either a linear or 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 or unsaturated fatty acid.

[0076] Examples of fatty acids include straight-chain or branched-chain fatty acids such as isobutyric acid, propionic acid, butanoic acid, pentanoic acid, hexanoic acid, heptanoic acid, octanoic acid, nonanoic acid, decanoic acid, undecanoic acid, dodecanoic acid, tridecanoic acid, tetradecanoic acid, pentadecanoic acid, hexadecanoic acid, heptadecanoic acid, octadecanoic acid, nonadecanoic acid, icosanoic acid, and oleic acid, as well as so-called neo acids in which the α carbon atom is quaternary. More specifically, isobutyric acid, valeric acid (n-pentanoic acid), caproic acid (n-hexanoic acid), enanthic acid (n-heptanoic acid), caprylic acid (n-octanoic acid), pelargonic acid (n-nonanoic acid), capric acid (n-decanoic acid), oleic acid (cis-9-octadecenoic acid), isopentanoic acid (3-methylbutanoic acid), 2-methylhexanoic acid, 2-ethylpentanoic acid, 2-ethylhexanoic acid, 3,5,5-trimethylhexanoic acid, and the like are preferred.

[0077] The POE may be a partial ester in which some of the hydroxyl groups of the polyol remain unesterified, or a complete ester in which all of the hydroxyl groups are esterified. The POE may be a mixture of a partial ester and a complete ester, but is preferably a complete ester.

[0078] As POE, from the viewpoint of superior hydrolytic stability, esters of hindered alcohols such as neopentyl glycol, trimethylolethane, trimethylolpropane, trimethylolbutane, di-(trimethylolpropane), tri-(trimethylolpropane), pentaerythritol, di-(pentaerythritol), and tri-(pentaerythritol) are preferred, esters of neopentyl glycol, trimethylolethane, trimethylolpropane, trimethylolbutane, and pentaerythritol are more preferred, and from the viewpoint of particularly superior compatibility with the refrigerant and hydrolytic stability, esters of pentaerythritol are even more preferred.

[0079] Specific examples of preferred POE include diesters of neopentyl glycol and 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 and 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 trimethylolpropane and 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 one or more fatty acids selected from the group consisting of trimethylolbutane, 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 trimethylolbutane, and 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; tetraesters of pentaerythritol, and 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.

[0080] The ester of two or more fatty acids may be a mixture of two or more esters of one fatty acid and a polyol. Among POEs, esters of two or more mixed fatty acids and polyols are preferred from the viewpoints of improving low-temperature properties and compatibility with refrigerants.

[0081] (Mineral Oil) Examples of mineral oils include oils obtained by atmospheric distillation of paraffinic crude oil, intermediate base crude oil, or naphthenic crude oil, or by vacuum distillation of the atmospheric residual oil obtained by atmospheric distillation of crude oil, and then refining the lubricating oil fraction by one or more of the following processes: solvent deasphalting, solvent extraction, hydrocracking, solvent dewaxing, catalytic dewaxing, hydrorefining, etc.; and oils produced by isomerizing mineral oil wax. When the base oil (A) contains a mineral oil, the mineral oil may be used alone or in combination of two or more kinds.

[0082] (Preferred embodiment of base oil (A)) In the refrigerating machine oil composition according to one embodiment of the present invention, the main component of the base oil (A) is preferably the above-mentioned base oil (A1), more preferably the above-mentioned base oil (A2), and further preferably the above-mentioned base oil (A3) or the above-mentioned base oil (A4). In this specification, the term "main component" refers to the component having the highest content. The content of base oil (A1), base oil (A2), base oil (A3), or base oil (A4) in base oil (A) is preferably 50 to 100 mass%, more preferably 60 to 100 mass%, even more preferably 70 to 100 mass%, still more preferably 80 to 100 mass%, and even more preferably 90 to 100 mass%, based on the total amount (100 mass%) of base oil (A).

[0083] The base oil (A) may contain further base oils other than the base oil (A1), the base oil (A2), the base oil (A3), or the base oil (A4), within the range not impairing the effects of the present invention. Other base oils include synthetic oils such as polyesters, polycarbonates, hydrogenated α-olefin oligomers, alicyclic hydrocarbon compounds, alkylated aromatic hydrocarbon compounds, and oils produced by isomerizing GTL WAX (gas-to-liquid wax) produced by the Fischer-Tropsch process or the like, which do not fall under the above-mentioned PVE, PAG, ECP, and POE.

[0084] (Kinematic viscosity of base oil (A) at 40°C) The kinematic viscosity of the base oil (A) at 40°C is preferably 5 to 120 mm2 / s, more preferably 10 to 110 mm 2 / s, more preferably 30 to 100 mm 2 When the 40° C. kinematic viscosity of the base oil (A) is within the above range, the wear resistance is improved. In this specification, the 40° C. kinematic viscosity is a value measured in accordance with JIS K 2283:2000.

[0085] <First phosphorus compounds (B)> The refrigerator oil composition of the present invention contains a first phosphorus-based compound (B). The first phosphorus compound (B) is at least one selected from the group consisting of a first phosphite (B1) and a second phosphite (B2). The refrigerating machine oil composition of the present invention exhibits a remarkable effect of improving wear resistance by containing the first phosphorus-based compound (B). If the refrigerating machine oil composition does not contain the first phosphorus-based compound (B), the remarkable effect of improving wear resistance is not exhibited, and the wear resistance of the refrigerating machine oil composition cannot be improved under severe conditions. The first phosphite (B1) and the second phosphite (B2) used as the first phosphorus compound (B) will be described in detail below.

[0086] (primary phosphite (B1)) The primary phosphite (B1) is a compound represented by the following general formula (1). [ka]

[0087] In the above general formula (1), R 11 R is an aromatic group represented by the following general formula (1a). 12 is an aliphatic hydrocarbon group having 6 to 20 carbon atoms. n is an integer of 1 to 3. When n is 2 or more, multiple R 11 -O- may be the same or different. When n=1, a plurality of -OR 12 may be the same or different from each other.

[0088] [ka] In the above general formula (1a), R 13 is a branched aliphatic hydrocarbon group having 3 to 20 carbon atoms. m is an integer of 0 to 5. When m is 2 or more, multiple R 13 may be the same or different from each other. 11 This indicates the bond position with the oxygen atom in -O-.

[0089] The primary phosphite (B1) may be used alone or in combination of two or more kinds.

[0090] In the above general formula (1), R 12 From the viewpoint of easily exerting the effect of improving abrasion resistance, the aliphatic hydrocarbon group having 6 to 20 carbon atoms represented by the following formula is preferably an alkyl group having 6 to 20 carbon atoms or an alkenyl group having 6 to 20 carbon atoms, and more preferably an alkyl group having 6 to 20 carbon atoms.

[0091] R 12 Examples of the alkyl group having 6 to 20 carbon atoms represented by the formula (I) include a hexyl group, a heptyl group, an octyl group, a nonyl group, a decyl group, an undecyl group, a dodecyl group, a tridecyl group, a tetradecyl group, a pentadecyl group, a hexadecyl group, a heptadecyl group, an octadecyl group, a nonadecyl group, and an icosyl group. The alkyl group may be linear or branched. The branched structure (number of branches, branching position) of the branched alkyl group is not particularly limited, but from the viewpoint of more significantly improving the abrasion resistance, the alkyl group is preferably a branched alkyl group. From the same viewpoint, the alkyl group preferably has 6 to 16 carbon atoms, and more preferably has 6 to 12 carbon atoms.

[0092] R 12Examples of the alkenyl group having 6 to 20 carbon atoms represented by the formula (I) include a hexenyl group, a heptenyl group, an octenyl group, a nonenyl group, a decenyl group, an undecenyl group, a dodecenyl group, a tridecenyl group, a tetradecenyl group, a pentadecenyl group, a hexadecenyl group, a heptadecenyl group, an octadecenyl group, a nonadecenyl group, and an icosenyl group. The alkenyl group may be linear or branched. The branched structure (number of branches, branching position) of the branched alkyl group is not particularly limited, but from the viewpoint of more clearly exhibiting the effect of improving wear resistance, it is preferable that the alkenyl group is branched. The position and number of unsaturated bonds of the linear or branched alkenyl group are not particularly limited. From the same viewpoint, the alkenyl group preferably has 6 to 16 carbon atoms, and more preferably 6 to 12 carbon atoms.

[0093] Here, in order to more significantly improve the wear resistance, R 12 is preferably a branched alkyl group having 6 to 16 carbon atoms, more preferably a branched alkyl group having 6 to 12 carbon atoms, and further preferably a 2-ethylhexyl group or an isodecyl group.

[0094] In the above general formula (1a), R 13 From the viewpoint of easily exerting the effect of improving abrasion resistance, the branched aliphatic hydrocarbon group having 3 to 20 carbon atoms represented by the formula (I) is preferably a branched alkyl group having 3 to 20 carbon atoms or a branched alkenyl group having 3 to 20 carbon atoms, and more preferably a branched alkyl group having 3 to 20 carbon atoms.

[0095] R 13Examples of the branched alkyl group having 3 to 20 carbon atoms represented by the formula (I) include a branched propyl group, a branched butyl group, a branched pentyl group, a branched hexyl group, a branched heptyl group, a branched octyl group, a branched nonyl group, a branched decyl group, a branched undecyl group, a branched dodecyl group, a branched tridecyl group, a branched tetradecyl group, a branched pentadecyl group, a branched hexadecyl group, a branched heptadecyl group, a branched octadecyl group, a branched nonadecyl group, and a branched icosyl group. The branched structure (number of branches, branching positions) of the alkyl group is not particularly limited, but from the viewpoint of making it easier to exhibit the effect of improving abrasion resistance more significantly and from the viewpoint of improving thermal stability, the number of branches is preferably 1 or more, more preferably 2 or more, and even more preferably 2. From the same viewpoint, the branching position is preferably the carbon adjacent to the phenyl group (i.e., the α carbon). From the same viewpoint, the number of carbon atoms in the alkyl group is preferably 3 or more. Also, it is preferably 10 or less, more preferably 8 or less, and even more preferably 6 or less. The upper and lower limits of these numerical ranges can be arbitrarily combined. Specifically, it is preferably 3 to 10, more preferably 3 to 8, and even more preferably 3 to 6.

[0096] R 13 Examples of the branched alkenyl group having 3 to 20 carbon atoms represented by the formula (I) include a branched propenyl group, a branched butenyl group, a branched pentenyl group, a branched hexenyl group, a branched heptenyl group, a branched octenyl group, a branched nonenyl group, a branched decenyl group, a branched undecenyl group, a branched dodecenyl group, a branched tridecenyl group, a branched tetradecenyl group, a branched pentadecenyl group, a branched hexadecenyl group, a branched heptadecenyl group, a branched octadecenyl group, a branched nonadecenyl group, and a branched icosenyl group. The branched structure (number of branches, branching position) of the alkenyl group is not particularly limited, but from the viewpoint of more prominently exhibiting the effect of improving wear resistance and from the viewpoint of improving thermal stability, the number of branches is preferably 1 or more, more preferably 2 or more, and even more preferably 2. From the same viewpoint, the branching position is preferably the carbon adjacent to the phenyl group (i.e., the α carbon). The position and number of unsaturated bonds of the alkenyl group are not particularly limited. From the same viewpoint, the number of carbon atoms in the branched alkenyl group is preferably 3 or more. Also, it is preferably 10 or less, more preferably 8 or less, and even more preferably 6 or less. The upper and lower limits of these numerical ranges can be arbitrarily combined. Specifically, it is preferably 3 to 10, more preferably 3 to 8, and even more preferably 3 to 6.

[0097] Here, from the viewpoint of making it easier to exhibit the effect of improving wear resistance more significantly and from the viewpoint of improving thermal stability, R 13 is preferably a branched alkyl group having 3 to 8 carbon atoms, more preferably a branched alkyl group having 3 to 6 carbon atoms, and further preferably a tert-pentyl group.

[0098] In the above general formula (1), n ​​is an integer of 1 to 3. When n is 2 or more, a plurality of R 11 -O- may be the same or different. When n=1, a plurality of -OR 12 may be the same or different from each other. Here, from the viewpoint of easily exerting the effect of improving the abrasion resistance and from the viewpoint of improving the thermal stability, n is preferably an integer of 2 to 3, and n is more preferably 3.

[0099] In the above general formula (1a), m is an integer of 0 to 5. When m is 2 or more, a plurality of R 13 may be the same or different from each other. From the viewpoint of making it easier to exhibit the effect of improving abrasion resistance more significantly and from the viewpoint of improving thermal stability, m is preferably an integer of 1 to 5, more preferably an integer of 1 to 4, even more preferably an integer of 1 to 3, and even more preferably an integer of 1 to 2. In particular, when n in the above general formula (1) is 3, by adjusting m to fall within the above range, the effect of improving the wear resistance can be more significantly exhibited. In addition, R 13 The bonding position of R to the phenyl group is not particularly limited. From the same viewpoint, when m=1, R 13 is preferably bonded to the para position. When m=2, one of R 13 is bonded to the para position, and the other R 13 is preferably bonded at the ortho position. When m>2, R 13 It is preferred that at least one of these is bonded at the para position and at least one of the remaining is bonded at the ortho position.

[0100] (Secondary phosphite (B2)) The secondary phosphite (B2) is a compound represented by the following general formula (2). [ka]

[0101] In the above general formula (2), R 21 and R 22 are each independently an aliphatic hydrocarbon group having 10 to 30 carbon atoms.

[0102] The secondary phosphite (B2) may be used alone or in combination of two or more kinds.

[0103] In the above general formula (1), R 21 and R 22From the viewpoint of making it easier to more significantly exhibit the effect of improving abrasion resistance, the aliphatic hydrocarbon group having 10 to 30 carbon atoms represented by the formula (I) is preferably an alkyl group having 10 to 30 carbon atoms or an alkenyl group having 10 to 30 carbon atoms, and more preferably an alkyl group having 10 to 30 carbon atoms.

[0104] R 21 and R 22 Examples of the alkyl group having 10 to 30 carbon atoms represented by the formula (I) include a decyl group, an undecyl group, a dodecyl group, a tridecyl group, a tetradecyl group, a pentadecyl group, a hexadecyl group, a heptadecyl group, an octadecyl group, a nonadecyl group, an icosyl group, a henoicosyl group, a tetracosyl group, and a triacontyl group. The alkyl group may be linear or branched. The branched structure (number of branches, branching positions) of the branched alkyl group is not particularly limited. Here, from the viewpoint of making it easier to exhibit a more significant effect of improving wear resistance, the alkyl group is preferably linear. From the same viewpoint, the alkyl group preferably has 14 to 24 carbon atoms, and more preferably has 16 to 20 carbon atoms.

[0105] R 21 and R 22 Examples of the alkenyl group having 10 to 30 carbon atoms represented by the formula (I) include a decenyl group, an undecenyl group, a dodecenyl group, a tridecenyl group, a tetradecenyl group, a pentadecenyl group, a hexadecenyl group, a heptadecenyl group, an octadecenyl group, a nonadecenyl group, an icosenyl group, a henicosenyl group, a tetracosenyl group, and a triacontenyl group. The alkenyl group may be linear or branched. The branched structure (number of branches, branching position) of the branched alkenyl group is not particularly limited. In addition, the position and number of unsaturated bonds of the linear or branched alkenyl group are not particularly limited. Here, from the viewpoint of making it easier to exhibit a more significant effect of improving wear resistance, the alkenyl group is preferably linear. From the same viewpoint, the alkenyl group preferably has 14 to 24 carbon atoms, and more preferably has 16 to 20 carbon atoms.

[0106] Here, in order to more significantly improve the wear resistance, R 21 and R 22 is preferably a linear alkyl group having 14 to 24 carbon atoms, more preferably a linear alkyl group having 16 to 20 carbon atoms, and further preferably an n-octadecyl group. In addition, R 21 and R 22 may be the same or different from each other, but is preferably the same.

[0107] (Preferred embodiment of the first phosphorus compound (B) and the content of the first phosphorus compound (B)) From the viewpoint of making it easier to exhibit a more significant effect of improving the wear resistance, the first phosphorus compound (B) is preferably a first phosphite (B1).

[0108] In addition, in the refrigerator oil composition according to one embodiment of the present invention, the phosphorus atom content (B P From the viewpoint of making it easier to exhibit the wear resistance improving effect more significantly, the content of the refrigerating machine oil composition is preferably 30 ppm by mass or more, more preferably 35 ppm by mass or more, even more preferably 40 ppm by mass or more, and even more preferably 45 ppm by mass or more. Also, the content is preferably 1,000 ppm by mass or less, more preferably 950 ppm by mass or less, and even more preferably 900 ppm by mass or less, based on the total amount of the refrigerating machine oil composition. The upper and lower limits of these numerical ranges can be arbitrarily combined. Specifically, the range is preferably 30 ppm by mass to 1,000 ppm by mass, more preferably 35 ppm by mass to 950 ppm by mass, even more preferably 40 ppm by mass to 900 ppm by mass, and still more preferably 45 ppm by mass to 900 ppm by mass.

[0109] In the refrigerating machine oil composition according to one embodiment of the present invention, the content of the first phosphorus-based compound (B) is the phosphorus atom content (B P ) may be adjusted to satisfy the above range. Specifically, the content of the first phosphorus compound (B) is preferably 0.05% by mass to 1% by mass, more preferably 0.1% by mass to 1% by mass, and even more preferably 0.1% by mass to 0.7% by mass, based on the total amount of the refrigerating machine oil composition.

[0110] <Secondary phosphorus compounds (C)> A refrigerator oil composition according to one embodiment of the present invention contains a base oil (A) and a first phosphorus-based compound (B), and preferably further contains a second phosphorus-based compound (C). The second phosphorus compound (C) is at least one selected from the group consisting of phosphoric acid compounds (C1) and organic phosphine oxide compounds (C2). The refrigerating machine oil composition of one embodiment of the present invention contains the first phosphorus-based compound (B) and the second phosphorus-based compound (C), and thus these act synergistically to further enhance the remarkable anti-wear effect provided by the first phosphorus-based compound (B). The phosphoric acid compound (C1) and the organic phosphine oxide compound (C2) used as the second phosphorus compound (C) will be described in detail below. In the following description, the "second phosphorus compound (C)" is also referred to as the "component (C)". The "phosphate compound (C1)" and the "organic phosphine oxide compound (C2)" are also referred to as the "component (C1)" and the "component (C2)", respectively.

[0111] (Phosphate compound (C1)) The phosphoric acid compound (C1) is preferably at least one selected from the group consisting of a phosphoric acid ester represented by the following general formula (c-1-i), and an acidic phosphoric acid ester represented by the following general formula (c-1-ii) or (c-1-iii): [ka]

[0112] In the above general formulae (c-1-i) to (c-1-iii), R 31 ~R 33 R is an alkyl group having 4 to 30 carbon atoms, an alkenyl group having 4 to 30 carbon atoms, an aryl group having 6 to 30 carbon atoms, an alkylaryl group having 7 to 30 carbon atoms, and an arylalkyl group having 7 to 30 carbon atoms. 31 ~R 33 may be the same or different from each other.

[0113] Examples of the phosphate ester represented by the general formula (c-1-i) include triphenyl phosphate, tricresyl phosphate, benzyl diphenyl phosphate, ethyl diphenyl phosphate, tributyl phosphate, ethyl dibutyl phosphate, cresyl diphenyl phosphate, dicresyl phenyl phosphate, ethyl phenyl diphenyl phosphate, diethyl phenyl phosphate, propyl phenyl diphenyl phosphate, dipropyl phenyl phosphate, triethyl phenyl phosphate, tripropyl phenyl phosphate, butyl phenyl diphenyl phosphate, dibutyl phenyl phosphate, tributyl phenyl phosphate, trihexyl phosphate, tri(2-ethylhexyl) phosphate, tridecyl phosphate, trilauryl phosphate, trimyristyl phosphate, tripalmityl phosphate, tristearyl phosphate, and trioleyl phosphate. The phosphate ester represented by the above general formula (c-1-i) may be used alone or in combination of two or more kinds.

[0114] Examples of the acidic phosphate ester represented by the above general formula (c-1-ii) or (c-1-iii) include 2-ethylhexyl acid phosphate, ethyl acid phosphate, butyl acid phosphate, oleyl acid phosphate, tetracosyl acid phosphate, isodecyl acid phosphate, lauryl acid phosphate, tridecyl acid phosphate, stearyl acid phosphate, and isostearyl acid phosphate. The acidic phosphate ester represented by the above general formula (c-1-ii) or (c-1-iii) may be used alone or in combination of two or more.

[0115] Here, from the viewpoint of more easily exerting the synergistic effect of improving the wear resistance by combining with the first phosphorus compound (B), the phosphoric acid compound (C1) is preferably a phosphoric acid ester represented by the above general formula (c-1-i). More preferably, in the phosphoric acid ester represented by the above general formula (c-1-i), R 31 ~R 33 is an alkylaryl group having 7 to 30 carbon atoms (preferably 7 to 20 carbon atoms, more preferably 7 to 10 carbon atoms). More preferably, the phosphate ester represented by the above general formula (c-1-i) is tricresyl phosphate.

[0116] (Organophosphine oxide compounds (C2)) The organic phosphine oxide compound (C2) may be an organic phosphine oxide compound having one phosphorus atom, or may be an organic phosphine oxide compound having two or more phosphorus atoms. An example of an organic phosphine oxide compound having one phosphorus atom is a compound represented by the following general formula (c-2-i), and an example of an organic phosphine oxide compound having two or more phosphorus atoms is a compound represented by the following general formula (c-2-ii).

[0117] [ka]

[0118] In formula (c-2-i), R 41 ~R 43 Each of R independently represents a substituted or unsubstituted hydrocarbon group having 1 to 20 carbon atoms. 44 ~R 47 R each independently represents a substituted or unsubstituted hydrocarbon group having 1 to 20 carbon atoms. 48represents a substituted or unsubstituted divalent hydrocarbon group having 1 to 20 carbon atoms which may contain an ether bond.

[0119] R 41 ~R 43 Examples of the substituted or unsubstituted hydrocarbon group having 1 to 20 carbon atoms represented by the formula (I) include a substituted or unsubstituted alkyl group having 1 to 20 carbon atoms, a substituted or unsubstituted alkenyl group having 2 to 20 carbon atoms, a substituted or unsubstituted alkynyl group having 2 to 20 carbon atoms, and a substituted or unsubstituted aryl group having 6 to 20 carbon atoms. Among these, a substituted or unsubstituted alkyl group having 1 to 20 carbon atoms and a substituted or unsubstituted aryl group having 6 to 20 carbon atoms are preferred, and a substituted or unsubstituted aryl group having 6 to 20 carbon atoms is more preferred. Examples of the substituents on these hydrocarbon groups include halogen atoms, hydroxy groups, amino groups, imino groups, amido groups, carboxy groups, alkyl groups having 1 to 5 carbon atoms, and alkoxy groups having 1 to 5 carbon atoms.

[0120] R 41 ~R 43 Examples of the substituted or unsubstituted alkyl group having 1 to 20 carbon atoms represented by the formula (I) include alkyl groups such as a methyl group, an ethyl group, an n-propyl group, an isopropyl group, an n-butyl group, an isobutyl group, a sec-butyl group, a tert-butyl group, various pentyl groups, various hexyl groups, various heptyl groups, various octyl groups, various nonyl groups, and various decyl groups; and cycloalkyl groups such as a cyclopentyl group, a cyclohexyl group, various methylcyclohexyl groups, various ethylcyclohexyl groups, various propylcyclohexyl groups, and various dimethylcyclohexyl groups. The alkyl group preferably has 2 to 10 carbon atoms, and more preferably 3 to 8 carbon atoms.

[0121] R 41 ~R 43Examples of the substituted or unsubstituted aryl group having 6 to 20 carbon atoms represented by the formula (I) include a substituted or unsubstituted phenyl group and a substituted or unsubstituted naphthyl group. Among these, a substituted or unsubstituted phenyl group is preferred. Examples of the substituted or unsubstituted phenyl group include a phenyl group, various methoxyphenyl groups, various dimethoxyphenyl groups, various trimethoxyphenyl groups, various ethoxyphenyl groups, 2,6-dimethyl-4-ethoxyphenyl groups, various methylphenyl groups, various dimethylphenyl groups, and various trimethylphenyl groups. Among these, a phenyl group (an unsubstituted phenyl group) is preferred. These aryl groups preferably have 6 to 10 carbon atoms, and more preferably 6 to 8 carbon atoms.

[0122] Examples of the organic phosphine oxide compound represented by the above general formula (c-2-i) include triphenylphosphine oxide and tri-n-octylphosphine oxide.

[0123] The organic phosphine oxide compounds represented by the above general formula (c-2-i) may be used alone or in combination of two or more.

[0124] In the above general formula (c-2-ii), R 44 ~R 47 As the substituted or unsubstituted hydrocarbon group having 1 to 20 carbon atoms represented by the formula (c-2-i), 41 ~R 43 The preferred embodiments are also the same as those of the substituted or unsubstituted hydrocarbon group having 1 to 20 carbon atoms represented by the following formula:

[0125] In the above general formula (c-2-ii), R 48Examples of the substituted or unsubstituted divalent hydrocarbon group having 1 to 20 carbon atoms, which may contain an ether bond, include a substituted or unsubstituted alkylene group having 1 to 20 carbon atoms, a substituted or unsubstituted alkenylene group having 2 to 20 carbon atoms, a substituted or unsubstituted alkynylene group having 2 to 20 carbon atoms, and a substituted or unsubstituted arylene group having 6 to 20 carbon atoms, which may contain an ether bond. Examples of the substituent of these hydrocarbon groups include the above-mentioned R 41 ~R 43 The substituents are the same as those mentioned above.

[0126] Examples of the substituted or unsubstituted alkylene group having 1 to 20 carbon atoms which may contain an ether bond include an ethylene group, a phenylethylene group, a 1,2-propylene group, a 2-phenyl-1,2-propylene group, a 1,3-propylene group, various butylene groups, various pentylene groups, various hexylene groups, various heptylene groups, various octylene groups, various nonylene groups, and various decylene groups. Examples of the substituted or unsubstituted arylene group having 6 to 20 carbon atoms which may contain an ether bond include various phenylene groups, various methylphenylene groups, various ethylphenylene groups, various dimethylphenylene groups, various naphthylenes, diphenylene ether groups, and divalent groups derived from 9,9-dimethylxanthene.

[0127] Examples of the organic phosphine oxide compound represented by the above general formula (c-2-ii) include bis[2-[(oxo)diphenylphosphino]phenyl]ether and the like.

[0128] The organic phosphine oxide compound represented by the above general formula (c-2-ii) may be used alone or in combination of two or more.

[0129] Here, from the viewpoint of more easily exerting the synergistic effect of improving wear resistance by combining with the first phosphorus compound (B), the organic phosphine oxide compound (C2) is preferably an organic phosphine oxide compound represented by the above general formula (c-2-i), and more preferably triphenylphosphine oxide.

[0130] (Preferred embodiment of the second phosphorus compound (C) and the content of the second phosphorus compound (C)) From the viewpoint of making it easier to exhibit a more significant effect of improving the wear resistance, the second phosphorus-based compound (C) is preferably an organic phosphine oxide compound (C2).

[0131] In the refrigerator oil composition according to one embodiment of the present invention, the phosphorus atom content (C P From the viewpoint of more easily exerting the synergistic effect of improving the wear resistance by combining with the first phosphorus compound (B), the content of the first phosphorus compound (C) is preferably 200 ppm by mass or more, more preferably 300 ppm by mass or more, and even more preferably 400 ppm by mass or more. Also, the content of the first phosphorus compound (C) is preferably 1,200 ppm by mass or less, more preferably 1,100 ppm by mass or less, and even more preferably 1,000 ppm by mass. The upper and lower limits of these numerical ranges can be arbitrarily combined. Specifically, the range is preferably 200 ppm by mass to 1,200 ppm by mass, more preferably 300 ppm by mass to 1,100 ppm by mass, and even more preferably 400 ppm by mass to 1,000 ppm by mass.

[0132] In the refrigerating machine oil composition according to one embodiment of the present invention, the content of the second phosphorus-based compound (C) is the phosphorus atom content (C P ) may be adjusted to satisfy the above range. Specifically, the content of the second phosphorus compound (C) is preferably 0.1 mass% or more, more preferably 0.2 mass% or more, and even more preferably 0.3 mass% or more, based on the total amount of the refrigerating machine oil composition. Also, it is preferably 1.5 mass% or less, and more preferably 1.2 mass% or less. The upper and lower limits of these numerical ranges can be arbitrarily combined. Specifically, the range is preferably 0.1 mass % to 1.5 mass %, more preferably 0.2 mass % to 1.5 mass %, and even more preferably 0.3 mass % to 1.2 mass %.

[0133] (Total content of first phosphorus compound (B) and second phosphorus compound (C)) In the refrigerating machine oil composition of one embodiment of the present invention, the total content of phosphorus atoms derived from the first phosphorus compound (B) and the second phosphorus compound (C) (B P +C P From the viewpoint of more easily exerting the synergistic effect of improving the wear resistance by combining with the first phosphorus compound (B), the content of the first phosphorus compound (C) is preferably 200 ppm by mass or more, more preferably 300 ppm by mass or more, and even more preferably 400 ppm by mass or more. Also, the content of the first phosphorus compound (C) is preferably 1,500 ppm by mass or less, more preferably 1,400 ppm by mass or less, and even more preferably 1,300 ppm by mass or less. The upper and lower limits of these numerical ranges can be arbitrarily combined. Specifically, the range is preferably 200 ppm by mass to 1,500 ppm by mass, more preferably 300 ppm by mass to 1,400 ppm by mass, and even more preferably 400 ppm by mass to 1,300 ppm by mass.

[0134] In the refrigerating machine oil composition according to one embodiment of the present invention, the total content of the first phosphorus-based compound (B) and the second phosphorus-based compound (C) is the total content of phosphorus atoms derived from the first phosphorus-based compound (B) and the second phosphorus-based compound (C) (B P +C P ) may be adjusted so as to satisfy the above range. Specifically, the total content of the first phosphorus compound (B) and the second phosphorus compound (C) is preferably 0.1 mass% or more, more preferably 0.3 mass% or more, based on the total amount of the refrigerating machine oil composition. Also, it is preferably 2.0 mass% or less, more preferably 1.5 mass% or less. The upper and lower limits of these numerical ranges can be arbitrarily combined. Specifically, the range is preferably 0.1 mass % to 2.0 mass %, more preferably 0.3 mass % to 2.0 mass %, and even more preferably 0.3 mass % to 1.5 mass %.

[0135] (Ratio of first phosphorus compound (B) to second phosphorus compound (C)) In the refrigerating machine oil composition of one embodiment of the present invention, the content ratio of the first phosphorus-based compound (B) to the second phosphorus-based compound (C) [(B) / (C)] is, in terms of mass ratio, preferably 1 / 12 to 2 / 1, more preferably 1 / 10 to 1.5 / 1, and even more preferably 1 / 9 to 1 / 1, from the viewpoint of more easily exerting the synergistic effect of improving wear resistance by the combination with the first phosphorus-based compound (B).

[0136] <Additives> The refrigerator oil composition according to one embodiment of the present invention may further contain additives within the range not impairing the effects of the present invention. From the viewpoint of improving the stability of the refrigerating machine oil composition, the additive preferably contains one or more selected from the group consisting of antioxidants, oiliness improvers, oxygen scavengers, copper deactivators, rust inhibitors, antifoaming agents, and viscosity index improvers, and more preferably contains at least an antioxidant. Furthermore, the refrigerating machine oil composition of one embodiment of the present invention may contain an extreme pressure agent that does not fall under the category of component (B) and component (C). These additives may be used alone or in combination of two or more. The total content of these additives is preferably 0 to 10 mass %, more preferably 0.01 to 5 mass %, and even more preferably 0.1 to 3 mass %, based on the total amount (100 mass %) of the refrigerator oil composition.

[0137] (Antioxidants) The antioxidant is preferably one or more selected from the group consisting of phenol-based antioxidants and amine-based antioxidants. Examples of the phenol-based antioxidant 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 the amine-based antioxidant include phenyl-α-naphthylamine and N,N'-diphenyl-p-phenylenediamine. Among these, 2,6-di-tert-butyl-p-cresol (DBPC) is more preferable. From the viewpoints of stability and antioxidant performance, the content of the antioxidant is preferably 0.01 to 5 mass%, more preferably 0.05 to 3 mass%, and even more preferably 0.1 to 1 mass%, based on the total amount (100 mass%) of the refrigerating machine oil composition.

[0138] (Oil improver) Examples of oiliness improvers 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; partial esters of polyhydric alcohols such as glycerin and sorbitol with aliphatic saturated or unsaturated monocarboxylic acids; and the like.

[0139] (Oxygen Scavenger) Examples of oxygen scavengers include aliphatic unsaturated compounds and terpenes having a double bond. The aliphatic unsaturated compound is preferably an unsaturated hydrocarbon, specifically, olefins, polyenes such as dienes and trienes, etc. As the olefin, from the viewpoint of reactivity with oxygen, α-olefins such as 1-tetradecene, 1-hexadecene, 1-octadecene, etc. are preferable. Other aliphatic unsaturated compounds than those mentioned above include those having the molecular formula C, which is selected from the viewpoint of reactivity with oxygen. 20 H 30 Unsaturated aliphatic alcohols having conjugated double bonds, such as vitamin A represented by O ((2E,4E,6E,8E)-3,7-dimethyl-9-(2,6,6-trimethylcyclohex-1-yl)nona-2,4,6,8-tetraen-1-ol), are preferred. As the terpene having a double bond, a terpene-based hydrocarbon having a double bond is preferable. From the viewpoint of reactivity with oxygen, α-farnesene (C 15 H 24: 3,7,11-trimethyldodeca-1,3,6,10-tetraene) and β-farnesene (C 15 H 24 :7,11-dimethyl-3-methylidene-dodeca-1,6,10-triene) is more preferred.

[0140] (copper deactivator) The copper deactivator may, for example, be N-[N,N'-dialkyl (alkyl group having 3 to 12 carbon atoms) aminomethyl]triazole.

[0141] (rust inhibitor) Examples of the rust inhibitor include metal sulfonates, aliphatic amines, organic phosphites, organic phosphates, organic sulfonic acid metal salts, organic phosphate metal salts, alkenyl succinates, and polyhydric alcohol esters.

[0142] (Antifoaming agent) The antifoaming agent includes silicone-based antifoaming agents such as silicone oil and fluorinated silicone oil.

[0143] (Viscosity index improver) Viscosity index improvers include polymethacrylates, polyisobutylenes, ethylene-propylene copolymers, hydrogenated styrene-diene copolymers, and the like.

[0144] (Extreme pressure agents not falling under component (B) and component (C)) Examples of extreme pressure agents that do not fall under the category of components (B) and (C) include metal salts of carboxylic acids, sulfur-based extreme pressure agents, etc. Also included are phosphorus-based extreme pressure agents that do not fall under the category of components (B) and (C).

[0145] Examples of the metal salt of a carboxylic acid include metal salts of a carboxylic acid having 3 to 60 carbon atoms (preferably 3 to 30 carbon atoms). Among these, one or more selected from the group consisting of metal salts of fatty acids having 12 to 30 carbon atoms and 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.

[0146] Examples of the sulfur-based extreme pressure agents include sulfurized oils and fats, sulfurized fatty acids, sulfurized esters, sulfurized olefins, dihydrocarbyl polysulfides, thiocarbamates, thioterpenes, and dialkylthiodipropionates.

[0147] Examples of phosphorus-based extreme pressure agents not corresponding to component (B) and component (C) include phosphites and acid phosphites not corresponding to component (B), phosphates not corresponding to component (C), acid phosphates not corresponding to component (C), and organic phosphine oxide compounds not corresponding to component (C).

[0148] Examples of phosphites that do not fall under the category of component (B) include compounds represented by the above general formula (1) where n = 0. Specific examples include trialkyl phosphites such as trioleyl phosphite. In addition, other phosphite esters that do not fall under the category of component (B) include those represented by the general formula (1) R 11 In the above general formula (1a), m is 1 or more, and R 13 is a straight-chain aliphatic hydrocarbon group. Specific examples include trisnonylphenyl phosphite.

[0149] Examples of the acid phosphite include aryl hydrogen phosphites and alkyl hydrogen phosphites. Specific examples include monoethyl hydrogen phosphite, mono-n-propyl hydrogen phosphite, mono-n-butyl hydrogen phosphite, mono-2-ethylhexyl hydrogen phosphite, monophenyl hydrogen phosphite, dihexyl hydrogen phosphite, diheptyl hydrogen phosphite, di-n-octyl hydrogen phosphite, di-2-ethylhexyl hydrogen phosphite, diphenyl hydrogen phosphite, and the like.

[0150] An example of a phosphorus-based extreme pressure agent (phosphate ester) not corresponding to component (C) is tetraphenyl-m-phenylene bisphosphate.

[0151] Here, in the refrigerating machine oil composition of the present invention, the component (B) exerts an effect as an extreme pressure agent. Also, in the refrigerating machine oil composition of one aspect of the present invention, the components (B) and (C) exert an effect as an extreme pressure agent. Therefore, the refrigerating machine oil composition of one aspect of the present invention may not contain an extreme pressure agent that does not fall under the components (B) and (C). When the refrigerating machine oil composition of the present invention contains an extreme pressure agent other than components (B) and (C), the content thereof is, from the viewpoint of lubricity and stability (improved thermal stability), preferably 0.1 mass % or less, more preferably 0.05 mass % or less, even more preferably 0.01 mass % or less, based on the total amount (100 mass %) of the refrigerating machine oil composition, and most preferably does not contain an extreme pressure agent other than components (B) and (C). Examples of extreme pressure agents not corresponding to components (B) and (C) include the compounds already mentioned, in particular, one or more selected from trisnonylphenyl phosphite and tetraphenyl-m-phenylene bisphosphate. [Method of producing the refrigerating machine oil composition of the present invention] The method for producing the refrigerator oil composition of the present invention is not particularly limited. For example, a method for producing a refrigerating machine oil composition according to one embodiment of the present invention includes a step of mixing a base oil (A) and a first phosphorus-based compound (B), The method for producing a refrigerating machine oil composition is such that the first phosphorus compound (B) is at least one selected from the group consisting of a first phosphite (B1) represented by the following general formula (1) and a second phosphite (B2) represented by the following general formula (2): [ka] [In the above general formula (1), R 11 R is an aromatic group represented by the following general formula (1a). 12 is an aliphatic hydrocarbon group having 6 to 20 carbon atoms. n is an integer of 1 to 3. When n is 2 or more, multiple R11 -O- may be the same or different. When n=1, a plurality of -OR 12 may be the same or different from each other. [ka] [In the above general formula (1a), R 13 is a branched aliphatic hydrocarbon group having 3 to 20 carbon atoms. m is an integer of 0 to 5. When m is 2 or more, multiple R 13 may be the same or different from each other. 11 This indicates the bond position with the oxygen atom in -O-. [ka] [In the above general formula (2), R 21 and R 22 are each independently an aliphatic hydrocarbon group having 10 to 30 carbon atoms.]

[0152] The method for mixing the above components is not particularly limited, and may be, for example, a method having a step of blending the first phosphorus compound (B) with the base oil (A). The components other than the first phosphorus compound (B) may be blended simultaneously with the base oil (A) or may be blended separately. Each component may be blended after being made into a solution (dispersion) by adding a diluent oil or the like. After blending each component, it is preferable to stir and uniformly disperse them by a known method.

[0153] [Physical properties of the refrigerating machine oil composition of the present invention] <Phosphorus atom content> The refrigerating machine oil composition according to one embodiment of the present invention has a phosphorus atom content of preferably 200 ppm by mass or more, more preferably 300 ppm by mass or more, and even more preferably 400 ppm by mass or more, based on the total amount of the refrigerating machine oil composition, and preferably 1,500 ppm by mass or less, more preferably 1,400 ppm by mass or less, and even more preferably 1,300 ppm by mass or less. The upper and lower limits of these numerical ranges can be arbitrarily combined. Specifically, the range is preferably 200 ppm by mass to 1,500 ppm by mass, more preferably 300 ppm by mass to 1,400 ppm by mass, and even more preferably 400 ppm by mass to 1,300 ppm by mass. The phosphorus atom content can be measured in accordance with ASTM D4951.

[0154] <Thermal stability> The refrigerating machine oil composition of one embodiment of the present invention has an acid value measured by the method described in the examples below, of preferably 0.50 mgKOH / g or less, more preferably 0.45 mgKOH / g or less, and even more preferably 0.40 mgKOH / g or less.

[0155] [Mixed composition for refrigerators] The refrigerating machine oil composition of the present invention is mixed with a refrigerant and used as a mixed composition for a refrigerating machine. That is, the mixed composition for a refrigerator of the present invention contains the refrigerator oil composition of the present invention and a refrigerant. While the amount of refrigeration oil composition used in the equipment is decreasing with the miniaturization of refrigeration machines in recent years, the refrigeration machine may have localized high temperature locations due to frictional heat in the sliding parts of the compressor caused by harsher operating conditions, etc. The mixed composition for refrigeration machines of the present invention, which contains the refrigeration oil composition of the present invention and a refrigerant, exhibits excellent wear resistance even under such harsh environments.

[0156] <Refrigerant> Examples of the refrigerant include fluorohydrocarbon refrigerants such as unsaturated fluorohydrocarbon compounds and saturated fluorohydrocarbon compounds; and natural refrigerants such as hydrocarbons, carbon dioxide, and ammonia. These may be used alone or in combination of two or more. Among these, the refrigerant is preferably one containing one or more selected from the group consisting of unsaturated fluorohydrocarbon compounds, saturated fluorohydrocarbon compounds, hydrocarbons, carbon dioxide, and ammonia, and more preferably one containing an unsaturated fluorohydrocarbon compound. Each refrigerant will be described below.

[0157] <Unsaturated fluorohydrocarbon compounds> Examples of the unsaturated fluorinated hydrocarbon compound include those having a carbon-carbon double bond, such as fluorinated linear or branched chain olefins having 2 to 6 carbon atoms and cyclic olefins having 4 to 6 carbon atoms. More specific examples include ethylene having 1 to 3 fluorine atoms introduced, propene having 1 to 5 fluorine atoms introduced, butene having 1 to 7 fluorine atoms introduced, pentene having 1 to 9 fluorine atoms introduced, hexene having 1 to 11 fluorine atoms introduced, cyclobutene having 1 to 5 fluorine atoms introduced, cyclopentene having 1 to 7 fluorine atoms introduced, and cyclohexene having 1 to 9 fluorine atoms introduced. Among these unsaturated fluorohydrocarbon compounds, propene fluorides are preferred, propene having 3 to 5 fluorine atoms introduced is more preferred, and propene having 4 fluorine atoms introduced is even more preferred.Specifically, preferred compounds include 1,3,3,3-tetrafluoropropene (R1234ze) and 2,3,3,3-tetrafluoropropene (R1234yf). These unsaturated fluorohydrocarbon compounds may be used alone or in combination of two or more, or may be used in combination with a refrigerant other than an unsaturated fluorohydrocarbon compound. Examples of the refrigerant used in combination with a refrigerant other than an unsaturated fluorohydrocarbon compound include a mixed refrigerant of a saturated fluorohydrocarbon compound and an unsaturated fluorohydrocarbon compound. Examples of the mixed refrigerant include a mixed refrigerant of R32 and R1234yf, a mixed refrigerant of R32, R1234ze and R152a (AC5, mixing ratio is 13.23:76.20:9.96), and the like.

[0158] <Saturated fluorohydrocarbon compounds> The saturated fluorinated hydrocarbon compound is preferably a fluoride of an alkane having 1 to 4 carbon atoms, more preferably a fluoride of an alkane having 1 to 3 carbon atoms, and even more preferably a fluoride of an alkane (methane or ethane) having 1 or 2 carbon atoms. Examples of the fluoride of methane or ethane include trifluoromethane (R23), difluoromethane (R32), 1,1-difluoroethane (R152a), 1,1,1-trifluoroethane (R143a), 1,1,2-trifluoroethane (R143), 1,1,1,2-tetrafluoroethane (R134a), 1,1,2,2-tetrafluoroethane (R134), and 1,1,1,2,2-pentafluoroethane (R125). Among these, difluoromethane and 1,1,1,2,2-pentafluoroethane are preferred. These saturated fluorohydrocarbon compounds may be used alone or in combination of two or more. Examples of the combination of two or more include a mixed refrigerant in which two or more saturated fluorohydrocarbon compounds having a carbon number of 1 to 3 are mixed, and a mixed refrigerant in which two or more saturated fluorohydrocarbon compounds having a carbon number of 1 to 2 are mixed. Examples of the mixed refrigerant 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).

[0159] <Natural refrigerant> The natural refrigerant may be one or more selected from the group consisting of a hydrocarbon (HC) refrigerant, carbon dioxide (CO2) and ammonia, and is preferably a hydrocarbon (HC) refrigerant. One of these may be used alone, or two or more may be used in combination, or the refrigerant may be combined with a refrigerant other than a natural refrigerant. Here, an example of a refrigerant used in combination with a refrigerant other than a natural refrigerant may be a mixed refrigerant with a saturated fluorohydrocarbon compound and / or an unsaturated fluorohydrocarbon compound. A specific example of a mixed refrigerant is a mixed refrigerant of carbon dioxide, R1234ze and R134a (AC6, blending ratio 5.15:79.02:15.41).

[0160] As the hydrocarbon (HC) refrigerant, a hydrocarbon having 1 to 8 carbon atoms is preferable, a hydrocarbon having 1 to 5 carbon atoms is more preferable, and a hydrocarbon having 3 to 5 carbon atoms is even more preferable. If the carbon number is 8 or less, the boiling point of the refrigerant is not too high, which is preferable as a refrigerant. Examples of the hydrocarbon refrigerant include methane, ethane, ethylene, propane (R290), cyclopropane, propylene, n-butane, isobutane (R600a), 2-methylbutane, n-pentane, isopentane, cyclopentane isobutane, and normal butane. The hydrocarbon refrigerant may be used alone or in combination of two or more kinds. The hydrocarbon refrigerant may be used alone or as a mixed refrigerant with a refrigerant other than the hydrocarbon refrigerant, such as a fluorocarbon refrigerant such as R134a, or carbon dioxide.

[0161] In the mixed composition for a refrigerator according to one embodiment of the present invention, the amounts of the refrigerant and the refrigerator oil composition used are, in terms of the mass ratio of the refrigerator oil composition / refrigerant, preferably 1 / 99 to 90 / 10, more preferably 5 / 95 to 70 / 30. When the mass ratio of the refrigerator oil composition / refrigerant is within this range, lubricity and suitable refrigeration capacity in the refrigerator can be obtained.

[0162] From the viewpoint of using a refrigerant with a low global warming potential, the refrigerant preferably contains an unsaturated fluorohydrocarbon compound. Furthermore, the content of the unsaturated fluorohydrocarbon compound in the refrigerant is preferably 50 mass% or more, more preferably 70 mass% or more, and even more preferably 90 mass% or more, based on the total amount (100 mass%) of the refrigerant, and it is even more preferable that the refrigerant is a refrigerant consisting only of the unsaturated fluorohydrocarbon compound.

[0163] [Physical properties of the mixture composition for refrigerator of the present invention] <Wear resistance> The amount of wear of the mixture composition for a refrigerator according to one embodiment of the present invention, measured by the method described in the Examples below, is preferably 5.0 mg or less, more preferably 4.0 mg or less, even more preferably 3.0 mg or less, still more preferably 2.5 mg or less, and even more preferably 2.0 mg or less.

[0164] [Uses of the refrigerating machine oil composition and the mixed composition for refrigerating machines of the present invention] The refrigerating machine oil composition and the mixed composition for refrigerating machine of the present invention are preferably used for, for example, air conditioners, refrigerators, vending machines, showcases, refrigeration systems, hot water supply systems, or heating systems. Examples of the 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.

[0165] [One aspect of the present invention provided] In one embodiment of the present invention, the following [1] to [8] are provided. [1] A composition comprising a base oil (A) and a first phosphorus compound (B), The first phosphorus compound (B) is at least one selected from the group consisting of a first phosphite (B1) represented by the following general formula (1) and a second phosphite (B2) represented by the following general formula (2): [ka] [In the above general formula (1), R 11 R is an aromatic group represented by the following general formula (1a). 12 is an aliphatic hydrocarbon group having 6 to 20 carbon atoms. n is an integer of 1 to 3. When n is 2 or more, multiple R 11 -O- may be the same or different. When n=1, a plurality of -OR 12 may be the same or different from each other. [ka] [In the above general formula (1a), R 13is a branched aliphatic hydrocarbon group having 3 to 20 carbon atoms. m is an integer of 0 to 5. When m is 2 or more, multiple R 13 may be the same or different from each other. 11 This indicates the bond position with the oxygen atom in -O-. [ka] [In the above general formula (2), R 21 and R 22 are each independently an aliphatic hydrocarbon group having 10 to 30 carbon atoms.] [2] The refrigerator oil composition according to [1], wherein m in the general formula (1a) is an integer of 1 to 5. [3] Further, the composition contains a second phosphorus compound (C), The refrigerating oil composition according to [1] or [2], wherein the second phosphorus compound (C) is one or more selected from the group consisting of a phosphoric acid compound (C1) and an organic phosphine oxide compound (C2). [4] The refrigerating oil composition according to any one of [1] to [3], wherein the phosphorus atom content is 200 ppm by mass to 1,500 ppm by mass based on the total amount of the refrigerating oil composition. [5] The refrigeration oil composition according to any one of [1] to [4], wherein the base oil (A) comprises one or more selected from the group consisting of polyalkylene glycols, polyvinyl ethers, copolymers of poly(oxy)alkylene glycols or monoethers thereof with polyvinyl ethers, polyol esters, and mineral oils. [6] A method for producing a composite oil, comprising the steps of: mixing a base oil (A) with a first phosphorus-based compound (B); The method for producing a refrigerating machine oil composition, wherein the first phosphorus compound (B) is at least one selected from the group consisting of a first phosphite (B1) represented by the following general formula (1) and a second phosphite (B2) represented by the following general formula (2): [ka] [In the above general formula (1), R 11R is an aromatic group represented by the following general formula (1a). 12 is an aliphatic hydrocarbon group having 6 to 20 carbon atoms. n is an integer of 1 to 3. When n is 2 or more, multiple R 11 -O- may be the same or different. When n=1, a plurality of -OR 12 may be the same or different from each other. [ka] [In the above general formula (1a), R 13 is a branched aliphatic hydrocarbon group having 3 to 20 carbon atoms. m is an integer of 0 to 5. When m is 2 or more, multiple R 13 may be the same or different from each other. 11 This indicates the bond position with the oxygen atom in -O-. [ka] [In the above general formula (2), R 21 and R 22 are each independently an aliphatic hydrocarbon group having 10 to 30 carbon atoms.] [7] A mixed composition for a refrigerator, comprising the refrigerator oil composition according to any one of [1] to [5] and a refrigerant. [8] The mixture composition for a refrigerator according to [7], wherein the refrigerant comprises at least one selected from the group consisting of unsaturated fluorohydrocarbon compounds, saturated fluorohydrocarbon compounds, hydrocarbons, carbon dioxide, and ammonia. EXAMPLES

[0166] The present invention will be specifically described with reference to the following examples, although the present invention is not limited to the following examples.

[0167] <Properties of base oil (A)> The 40° C. kinematic viscosity of the base oil (A) used in each of the Examples and Comparative Examples was measured in accordance with JIS K2283:2000.

[0168] <Details of each component used in preparation of refrigerator oil composition> Details of each component used in the preparation of the refrigerator oil composition are shown below.

[0169] 1. Base oil (A) (1) PAG Polyoxypropylene glycol monomethyl ether, 40℃ kinematic viscosity: 49mm 2 / s (2) PVE Copolymer of polyethyl vinyl ether and polyisobutyl vinyl ether (constituent units of ethyl vinyl ether:constituent units of polyisobutyl vinyl ether = 9:1 (molar ratio)), kinematic viscosity at 40°C: 67mm 2 / s

[0170] 2. Primary phosphorus compounds (B) (1) Primary phosphite (B1)-1 Isodecyl diphenyl phosphite (JPM-311, manufactured by Johoku Chemical Co., Ltd., a compound represented by the following formula (1-1), phosphorus atom content: 8.1% by mass) [ka] The compound represented by the above formula (1-1) is a compound represented by the general formula (1), in which n=2 and two R 11 -O- is the same, and R 12 In the general formula (1a), m=0. In the above formula (1-1), "-iC 10 H 21 " means an isodecyl group. The same applies in the following explanations.

[0171] (2) Primary phosphite (B1)-2 2-Ethylhexyldiphenylphosphite (JPM-308, manufactured by Johoku Chemical Co., Ltd., a compound represented by the following formula (1-2), phosphorus atom content: 8.6% by mass) [ka] The compound represented by the above formula (1-2) is a compound represented by the general formula (1), in which n=2 and two R 11 -O- is the same, and R 12 In the general formula (1a), m=0.

[0172] (3) Primary phosphite (B1)-3 Phenyl diisodecyl phosphite (manufactured by Sakai Chemical Industry Co., Ltd., Chelex D, a compound represented by the following formula (1-3), phosphorus atom content: 7.1% by mass) [ka] The compound represented by the above formula (1-3) is a compound represented by the general formula (1), in which n=1 and two -OR 12 are the same, and R 12 In the general formula (1a), m=0.

[0173] (4) Primary phosphite (B1)-4 A reaction product of bis[2,4-bis(2-methylbutan-2-yl)phenyl]4-(2-methylbutan-2-yl)phenyl phosphite, 2,4-bis(2-methylbutan-2-yl)phenyl bis[4-(2-methylbutan-2-yl)phenyl]phosphite, and tris[4-(2-methylbutan-2-yl)phenyl]phosphite (manufactured by Addivant, WESTON (registered trademark) 705, a mixture of compounds represented by the following formulas (1-4) to (1-7), phosphorus atom content: 4.9% by mass).

[0174] [ka] The compound represented by the above formula (1-4) is a compound represented by the general formula (1), in which n=3 and three R11 In addition, in the general formula (1a), m=1 and R 13 is a tert-pentyl group (bonding position to the phenyl group: para position).

[0175] [ka] The compound represented by the above formula (1-5) is a compound represented by the general formula (1), in which n=3 and three R 11 In addition, the compounds represented by the general formula (1a) include two identical R 11 -R in -O 11 where m=1 and R 13 is a tert-pentyl group (bonding position to the phenyl group: para position). 11 -R in -O 11 m=2, R 13 is a tert-pentyl group (bonding positions to the phenyl group: ortho and para positions).

[0176] [ka] The compound represented by the above formula (1-6) is a compound represented by the general formula (1), in which n=3 and three R 11 In addition, the compounds represented by the general formula (1a) include two identical R 11 -R in -O 11 m=2, R 13 is a tert-pentyl group (bonding positions to the phenyl group: ortho and para positions). 11 -R in -O 11 where m=1 and R 13 is a tert-pentyl group (bonding position to the phenyl group: para position).

[0177] [ka] The compound represented by the above formula (1-7) is a compound represented by the general formula (1), in which n=3 and three R 11 In addition, in the general formula (1a), m=2 and R 13 is a tert-pentyl group (bonding positions to the phenyl group: ortho and para positions).

[0178] (5) Secondary phosphite (B2)-1 Distearyl pentaerythritol diphosphite (JPP-2000PT, manufactured by Johoku Chemical Co., Ltd., a compound represented by the following formula (2-1), phosphorus atom content: 4.2% by mass) [ka] The compound represented by the above formula (2-1) is a compound represented by the general formula (2), 21 and R 22 is a stearyl group (n-octadecyl group).

[0179] 3. Phosphite (B'): Comparative Example Compound (1) Phosphite (B')-1 Trioleyl phosphite (JP-318-O, manufactured by Johoku Chemical Co., Ltd., a compound represented by the following formula (3-1), phosphorus atom content: 3.7% by mass) The phosphite (B')-1 is a phosphite in which n=0 in the general formula (1) and does not belong to the primary phosphorus compounds (B). [ka]

[0180] (2) Phosphite (B')-2 Trisnonylphenyl phosphite (manufactured by Sakai Chemical Industry Co., Ltd., TNPP, a compound represented by the following formula (3-2), phosphorus atom content: 4.1% by mass) The phosphite ester (B')-2 is represented by the general formula (1a), R 13 is a phosphite ester in which the alkyl group has a straight chain, and is not a primary phosphorus compound (B). [ka] In the above formula (3-2), "-nCH 19 " means a n-nonyl group.

[0181] 4. Secondary phosphorus compounds (C) (1) Phosphate compounds (C1) Tricresyl phosphate (phosphorus atom content: 8.4% by mass) (2) Organic phosphine oxide compounds (C2) Triphenylphosphine oxide (phosphorus atom content: 10.9% by mass)

[0182] 5. Phosphorus compounds that do not belong to either primary phosphorus compounds (B) or secondary phosphorus compounds (C) Tetraphenyl-m-phenylene bisphosphate

[0183] 6. Antioxidants Di-tert-butyl-p-cresol (DBPC)

[0184] [Examples 1 to 29 and Comparative Examples 1 to 12] Refrigerating machine oil compositions having the compositions shown in Tables 1 to 4 were prepared, and their wear resistance was evaluated by the Falex wear test described below. The evaluation results are shown in Tables 1 to 4. The units of values ​​for the blended compositions in Tables 1 to 4 are "mass %." In addition, in Tables 1 to 4, the compound name of the primary phosphite (B1)-4 is expressed as "triphenyl phosphite having three phenyl groups substituted with branched alkyl groups." In addition, the P atom content derived from the first phosphorus compound (B), the P atom content derived from the phosphite ester (B'), and the P atom content derived from the second phosphorus compound (C) shown in Tables 1 to 4 were calculated from the P atom content of each raw material.

[0185] <Falex abrasion test> The following pins and blocks were prepared: Pin: SAE-3135 Block: AISI-1137 The following tests were carried out using a Falex testing machine in accordance with ASTM D2670. The pin and block were set in a Falex tester, and 300 g of the refrigeration oil composition to be evaluated was placed in the test container, which was filled with 30 g of R1234yf as a refrigerant, and the test container was sealed.Then, the rotation speed was set to 0.09 m / s, the oil temperature was set to 60°C, and the load was set to 1,779 N, and the test container was operated for 60 minutes, and the total wear amount (mg) of the pin and block was measured. This Falex test was conducted under harsher conditions than usual, with higher oil temperatures and loads than usual. The evaluation criteria were as follows: The smaller the amount of wear (mg), the more excellent the wear resistance. Rating S (pass): 2.0 mg or less Grade A (pass): Over 2.0mg and up to 2.5mg Grade B (pass): over 2.5 mg and under 5.0 mg Grade C (fail): 5.0 mg or more

[0186] [Table 1]

[0187] [Table 2]

[0188] [Table 3]

[0189] [Table 4]

[0190] The following can be seen from Tables 1 to 4. It is clear that all of the refrigerating machine oil compositions of Examples 1 to 29 are excellent in wear resistance. In contrast, it is seen that the refrigerant oil compositions in which tricresyl phosphate, which belongs to the phosphoric acid compound (C1) among the second phosphorus compounds (C), was blended without blending the first phosphorus compound (B), as in Comparative Examples 1, 2, 7, and 8, had inferior wear resistance. In addition, it is found that the refrigerant oil compositions in which triphenylphosphine oxide, which belongs to the organic phosphine oxide compound (C2) among the second phosphorus compounds (C), is blended without blending the first phosphorus compound (B), as in Comparative Examples 3 and 4, have inferior wear resistance. Moreover, it is understood that the refrigerating machine oil compositions in which trioleyl phosphite, which is a phosphite ester not belonging to the primary phosphorus compounds (B), is blended, such as in Comparative Examples 5 and 9, are inferior in wear resistance. Moreover, it is understood that the refrigerating machine oil compositions in which trisnonylphenyl phosphite, which is a phosphite ester not belonging to the primary phosphorus compound (B), is blended, such as in Comparative Examples 6 and 10, are inferior in wear resistance. In addition, it is found that refrigerant oil compositions containing neither the first phosphorus-based compound (B) nor the second phosphorus-based compound (C), but containing tetraphenyl-m-phenylene bisphosphate, a compound that does not belong to either the first phosphorus-based compound (B) or the second phosphorus-based compound (C), as in Comparative Examples 11 and 12, have poor wear resistance.

[0191] <Autoclave test> An autoclave vessel (volume: 200 mL) was charged with Fe, Cu, and Al as catalysts, and further charged with a mixture of 20 g of the refrigerating machine oil composition of Example 19 and Comparative Examples 6, 11, and 12 and 20 g of a refrigerant (R1234yf), respectively, and also charged with 2,000 ppm by mass of moisture. After maintaining the vessel at 175°C for 336 hours, the acid value (mgKOH / g) was evaluated. The acid value was measured by indicator photometric titration method (see Appendix 1 of the JIS standard) in accordance with JIS K2501:2003. The evaluation criteria were as follows: The smaller the acid value, the more excellent the thermal stability. Rating A (pass): 0.5 mgKOH / g or less Grade B (fail): Over 0.5 mgKOH / g and up to 1.0 mgKOH / g Rating C (fail): Over 1.0 mgKOH / g

[0192] The results of the autoclave test are shown in Table 5.

[0193] [Table 5]

[0194] The results shown in Table 5 reveal the following: It is clear that the refrigerator oil composition shown in Example 19 has excellent thermal stability. In contrast, when trisnonylphenyl phosphite, a phosphite ester not corresponding to the primary phosphorus compound (B), is used as in Comparative Example 6, or tetraphenyl-m-phenylene bisphosphate, a compound not corresponding to either the primary phosphorus compound (B) or the secondary phosphorus compound (C), is used as in Comparative Examples 11 and 12, it is found that the thermal stability is poor.

Claims

1. Contains a base oil (A) and a first phosphorus-based compound (B), The base oil (A) contains one or more base oils (A2) selected from the group consisting of polyvinyl ethers and polyalkylene glycols, The content of the base oil (A2) in the base oil (A) is 50 to 100 mass% based on the total amount of the base oil (A), The first phosphorus compound (B) is at least one selected from the group consisting of a first phosphite (B1) represented by the following general formula (1) and a second phosphite (B2) represented by the following general formula (2): Further, it contains a second phosphorus compound (C), The second phosphorus-based compound (C) is at least one selected from the group consisting of a phosphoric acid compound (C1) and an organic phosphine oxide compound (C2). 【Chemistry 1】 [In the above general formula (1), R １１ R is an aromatic group represented by the following general formula (1a). １２ is an aliphatic hydrocarbon group having 6 to 20 carbon atoms. n is an integer of 1 to 3. When n is 2 or more, a plurality of R １１ -O- may be the same or different. When n=1, a plurality of -O-R １２ may be the same or different from each other. 【Chemistry 2】 [In the above general formula (1a), R １３ is a branched aliphatic hydrocarbon group having 3 to 20 carbon atoms. m is an integer of 0 to 5. When m is 2 or more, a plurality of R １３ may be the same or different from each other. １１ This indicates the bonding position of the oxygen atom in —O—.] 【Chemistry 3】 [In the above general formula (2), R ２１ and R ２２ are each independently an aliphatic hydrocarbon group having 10 to 30 carbon atoms.

2. The refrigerator oil composition according to claim 1, wherein m in the general formula (1a) is an integer of 1 to 5.

3. The refrigerating machine oil composition according to claim 1 or 2, wherein the phosphorus atom content is 200 ppm by mass to 1,500 ppm by mass based on the total amount of the refrigerating machine oil composition.

4. The method includes a step of mixing a base oil (A), a first phosphorus-based compound (B), and a second phosphorus-based compound (C), The base oil (A) contains one or more base oils (A2) selected from the group consisting of polyvinyl ethers and polyalkylene glycols, The content of the base oil (A2) in the base oil (A) is 50 to 100 mass% based on the total amount of the base oil (A), The first phosphorus compound (B) is at least one selected from the group consisting of a first phosphite (B1) represented by the following general formula (1) and a second phosphite (B2) represented by the following general formula (2): The second phosphorus compound (C) is at least one selected from the group consisting of a phosphoric acid compound (C1) and an organic phosphine oxide compound (C2). 【Chemistry 4】 [In the above general formula (1), R １１ R is an aromatic group represented by the following general formula (1a). １２ is an aliphatic hydrocarbon group having 6 to 20 carbon atoms. n is an integer of 1 to 3. When n is 2 or more, a plurality of R １１ -O- may be the same or different. When n=1, a plurality of -O-R １２ may be the same or different from each other. 【Chemistry 5】 [In the above general formula (1a), R １３ is a branched aliphatic hydrocarbon group having 3 to 20 carbon atoms. m is an integer of 0 to 5. When m is 2 or more, a plurality of R １３ may be the same or different from each other. １１ This indicates the bonding position of the oxygen atom in —O—.] 【Chemistry 6】 [In the above general formula (2), R ２１ and R ２２ are each independently an aliphatic hydrocarbon group having 10 to 30 carbon atoms.

5. A mixed composition for a refrigerator comprising the refrigerator oil composition according to any one of claims 1 to 3 and a refrigerant.

6. 6. The mixture composition for a refrigerator according to claim 5, wherein the refrigerant comprises at least one selected from the group consisting of unsaturated fluorohydrocarbon compounds, saturated fluorohydrocarbon compounds, hydrocarbons, carbon dioxide, and ammonia.

7. The mixture composition for a refrigeration machine according to claim 5, wherein the refrigerant comprises an unsaturated fluorohydrocarbon compound.

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