JP7144297B2 - Method for improving ignition resistance of refrigerating machine oil and refrigerating machine oil with improved ignition resistance - Google Patents

Description

TECHNICAL FIELD The present invention relates to a method for improving ignition resistance of refrigerating machine oil and refrigerating machine oil with improved ignition resistance.

Refrigerating machine oil is used as a lubricating oil for refrigerant compressors of refrigerators, refrigerating air conditioners, and the like, and is used in a wide temperature range from high to low temperatures in the refrigerant circulation cycle of the refrigerator. Therefore, refrigerating machine oils are required to have basic performance as lubricating oils, as well as compatibility with refrigerants, low-temperature properties, and the like. Among the low GWP refrigerants used in recent years, there are refrigerants classified as mildly flammable refrigerants. In refrigerators using such mildly flammable refrigerants, it is important to ensure safety by making them flame-retardant from the viewpoint of fire resistance and ignition resistance.

As a refrigerating machine oil capable of achieving both low-temperature properties and flame retardancy, Patent Document 1 discloses a refrigerating machine oil containing a specific ester-based base oil and used together with a mildly flammable refrigerant.

WO2016/072284

An object of the present invention is to provide a method for obtaining a refrigerating machine oil with improved safety from the viewpoint of fire resistance and a refrigerating machine oil with improved fire resistance.

The present invention provides a method for improving the ignition resistance of a refrigerating machine oil, comprising the step of adding an amine compound to an oil or oil composition containing a base oil containing an ether compound to obtain a refrigerating machine oil. do.

The ether-based compound may be at least one selected from the group consisting of polyalkylene glycol-based compounds and polyvinyl ether-based compounds, and when the ether-based compound is a polyalkylene glycol-based compound, its weight average molecular weight Mw and number average molecular weight The ratio Mw/Mn to Mn may be 1.15 or less, and when the ether compound is a polyvinyl ether compound, the ratio Mw/Mn between the weight average molecular weight Mw and the number average molecular weight Mn is 1.25 or less. It's okay.

Refrigerating machine oil contains antiwear agents, acid scavengers, antioxidants other than the above amine compounds, extreme pressure agents, oiliness agents, antifoaming agents, metal deactivators, viscosity index improvers, pour point depressants, detergents It may further contain at least one additive selected from the group consisting of dispersants.

Refrigerant oil may be used together with mildly flammable refrigerant.

The present invention also provides a refrigerating machine oil with improved ignition resistance, containing a base oil containing an ether-based compound and an amine-based compound.

According to the present invention, it is possible to provide a method for obtaining a refrigerating machine oil with improved safety from the viewpoint of fire resistance and a refrigerating machine oil with improved fire resistance.

Preferred embodiments of the present invention are described in detail below.

A method for improving the ignition resistance of a refrigerating machine oil according to an embodiment of the present invention comprises adding an amine compound to an oil or oil composition containing a base oil containing an ether compound to obtain a refrigerating machine oil. Have a process.

The ether-based compound is preferably at least one selected from the group consisting of polyalkylene glycol-based compounds and polyvinyl ether-based compounds.

A polyalkylene glycol-based compound is represented, for example, by the following general formula (A).
R ^a —(OR ^c )n—OR ^b (A)
[In the formula (A), R ^a and R ^b may be the same or different and each represents a hydrogen atom, an alkyl group having 1 to 5 carbon atoms or an acyl group having 2 to 5 carbon atoms, and R ^c , represents an alkylene group having 2 to 4 carbon atoms, and n represents an integer of 6 to 80. ]

In formula (A), when R ^a and R ^b each represent an alkyl group or an acyl group, they may be linear or branched. Specific examples of the alkyl group include a methyl group, an ethyl group, a linear or branched propyl group, a linear or branched butyl group, a linear or branched pentyl group, and the like. mentioned. Specific examples of acyl groups include an acetyl group, a linear or branched propanoyl group, a linear or branched butanoyl group, a linear or branched pentanoyl group, and the like. Among these alkyl groups and acyl groups, from the viewpoint of compatibility with refrigerants, methyl group, ethyl group, linear or branched propyl group, linear or branched butyl group, acetyl group, It is preferably at least one selected from the group consisting of a straight-chain or branched propanoyl group and a straight-chain or branched butanoyl group, and is preferably selected from the group consisting of a methyl group, an ethyl group, and an acetyl group. is more preferably at least one of the groups, and more preferably a methyl group or an acetyl group. When the number of carbon atoms in the alkyl group and the acyl group is 5 or less, the composition range exhibiting compatibility with the refrigerant is widened, and poor lubrication of the refrigerant compressor and inhibition of heat exchange in the evaporator can be suppressed.

In general formula (A) above, R ^c represents an alkylene group having 2 to 4 carbon atoms. Specific examples of such an alkylene group include an ethylene group ₍ --CH.sub.2CH.sub.2--), a propylene group ₍ --CH _{( CH.sub.3} )CH.sub.2--) _, and a trimethylene group _{( --CH.sub.2CH.sub.2CH.sub.2--} ). , a butylene group (--CH(CH ₂ CH ₃ )CH ₂ --), a tetramethylene group (--CH ₂ CH ₂ CH ₂ CH ₂ --), and the like. Among these alkylene groups, ethylene group, propylene group, butylene group and tetramethylene group are preferred. In addition, among the alkylene groups represented by R ^c , the proportion of alkylene groups having 2 carbon atoms (that is, ethylene groups) is preferably 40 mol% or less, more preferably 30 mol% or less, and still more preferably 25 mol%. Below, it is particularly preferably 20 mol % or less. When the ratio of the alkylene group having 2 carbon atoms (ethylene group) is 40 mol % or less, the compatibility with the refrigerant is excellent, which is preferable.

The number average molecular weight Mn of the polyalkylene glycol-based compound is not particularly limited, but is usually 500 or more and 4000 or less, preferably 500 or more and 4000 or less, from the viewpoint of more effectively increasing the spontaneous ignition point due to the addition of the amine-based compound described later. It is 600 or more, more preferably 1000 or more, preferably 3000 or less, more preferably 2500 or less, still more preferably 2000 or less, and particularly preferably 1500 or less.

The ratio Mw/Mn between the weight average molecular weight Mw and the number average molecular weight Mn of the polyalkylene glycol compound is not particularly limited, but from the viewpoint of more effectively increasing the spontaneous ignition point by adding the amine compound described later, Usually 1.0 or more and 3.0 or less, preferably 1.05 or more, more preferably 1.08 or more, preferably 2.5 or less, more preferably 2.0 or less, more preferably 1.5 or less , more preferably 1.4 or less, still more preferably 1.3 or less, and particularly preferably 1.15 or less. However, in the polyalkylene glycol-based compound according to the present invention, even if Mw / Mn is more than 1.15 and 3.0 or less, by blending the amine-based compound of the present invention, a high autoignition point freezing You can get oil.

In addition, the weight average molecular weight Mw of the polyalkylene glycol-based compound according to the present embodiment may be appropriately selected so that Mn and Mw/Mn satisfy the above conditions.

Mw, Mn, and Mw/Mn of the polyalkylene glycol-based compound according to the present embodiment mean Mw, Mn, and Mw/Mn (polypropylene glycol (standard sample) conversion values) obtained by GPC analysis. Mw, Mn and Mw/Mn can be measured, for example, as follows.

Using chloroform as a solvent, a diluted solution with a sample concentration of 2% by mass is prepared and analyzed using a GPC device (Waters, Alliance 2695). The solvent flow rate is set to 1 ml/min, the analysis is performed using a column with an analyzable molecular weight of 100 to 10,000, and the refractive index as a detector. The relationship between column retention time and molecular weight is determined using a polypropylene glycol standard with a definite molecular weight, a calibration curve is prepared separately, and the molecular weight is determined from the obtained retention time.

The flash point of the polyalkylene glycol-based compound according to this embodiment is preferably 220° C. or higher, more preferably 230° C. or higher, and even more preferably 240° C. or higher. The flash point in the present invention means the flash point measured in accordance with JIS K2265-4 "Method for Determining Flash Point-Part 4: Cleveland Open Method".

The higher the spontaneous ignition point of the polyalkylene glycol-based compound according to the present embodiment, the easier it is to ensure safety. is 450° C. or lower, more preferably 420° C. or lower, and still more preferably 400° C. or lower. In addition, the spontaneous ignition point of the polyalkylene glycol-based compound is preferably 320° C. or higher, more preferably 340° C. or higher, and still more preferably 350° C. or higher. The spontaneous ignition point in the present invention means a value measured by a method based on ASTM E659-1978.

The kinematic viscosity at 100° C. of the polyalkylene glycol-based compound according to the present embodiment is preferably 5 to 20 mm ² /s, more preferably 6 to 18 mm ² /s, even more preferably 7 to 16 mm ² /s, particularly preferably 8-15 mm ² /s, most preferably 10-15 mm ² /s. When the kinematic viscosity at 100°C is at least the above lower limit value, the lubricity in the coexistence of the refrigerant is improved. Insufficient lubrication of the compressor and inhibition of heat exchange in the evaporator can be suppressed.

The kinematic viscosity at 40° C. of the polyalkylene glycol-based compound according to this embodiment is preferably 10 to 200 mm ² /s, more preferably 20 to 150 mm ² /s. When the kinematic viscosity at 40° C. is 10 ^{mm 2} /s or more, the lubricity and the hermeticity of the compressor tend to improve. The composition range exhibiting solubility is widened, and poor lubrication of the refrigerant compressor and inhibition of heat exchange in the evaporator can be suppressed. The kinematic viscosity in the present invention means the kinematic viscosity specified in JIS K2283-1993.

The pour point of the polyalkylene glycol-based compound according to the present embodiment is preferably -10°C or less, more preferably -20 to -50°C. When a polyalkylene glycol compound having a pour point of −10° C. or less is used, it tends to be possible to suppress solidification of the refrigerating machine oil in the refrigerant circulation system at low temperatures. In addition, the pour point in the present invention means the pour point defined in JIS K2269.

Although the hydroxyl value of the polyalkylene glycol-based compound according to the present embodiment is not particularly limited, it is preferably 100 mgKOH/g or less, more preferably 50 mgKOH/g or less, still more preferably 30 mgKOH/g or less, and most preferably 10 mgKOH/g or less. There is no particular lower limit, but it may be less than 1 mgKOH/g, may be 1 mgKOH/g or more, or may be 5 mgKOH/g or more.

The polyalkylene glycol-based compound according to the present embodiment can be synthesized using a known method (e.g., "Alkylene oxide polymer", Mitsuta Shibata et al., Kaibundo, published on November 20, 1990, reference). For example, alcohol (R ^a OH; R ^a has the same definition as R ^a in the general formula (A)) is subjected to addition polymerization of one or more predetermined alkylene oxides, and the terminal hydroxyl group is etherified or By esterification, the polyalkylene glycol-based compound represented by the general formula (A) is obtained. In addition, when using two or more different alkylene oxides in the above production process, the resulting polyalkylene glycol-based compound may be either a random copolymer or a block copolymer, but more oxidation stability Block copolymers are preferred from the viewpoint of their tendency to have excellent low-temperature fluidity, and random copolymers are preferred from the viewpoint of their tendency to exhibit excellent low-temperature fluidity.

In addition, in the process of producing the polyalkylene glycol-based compound according to the present embodiment, alkylene oxide such as propylene oxide may undergo a side reaction to form an unsaturated group such as an allyl group in the molecule. When an unsaturated group is formed in the polyalkylene glycol molecule, the thermal stability of the polyalkylene glycol compound itself is reduced, sludge is generated due to the formation of polymer, or the antioxidant property (antioxidant property) is reduced. Phenomena such as the formation of peroxides due to In particular, when a peroxide is produced, it decomposes to produce a compound having a carbonyl group, and the compound having a carbonyl group produces sludge, which easily causes clogging of the capillary.

Therefore, the polyalkylene glycol-based compound according to the present embodiment preferably has a low degree of unsaturation derived from an unsaturated group or the like. Specifically, the degree of unsaturation is 0.04 meq/g or less. is preferred, 0.03 meq/g or less is more preferred, and 0.02 meq/g or less is even more preferred. Moreover, the peroxide value is preferably 10.0 meq/kg or less, more preferably 5.0 meq/g or less, and even more preferably 1.0 meq/g or less. Furthermore, the carbonyl value is preferably 100 mass ppm or less, more preferably 50 mass ppm or less, and even more preferably 20 mass ppm or less.

The terms "unsaturation degree", "peroxide value" and "carbonyl value" used in the present invention refer to values measured according to the standard fats and oils analysis test method established by the Japan Oil Chemists' Society. That is, the degree of unsaturation in the present invention is defined by reacting a sample with Wiss solution (ICI-acetic acid solution), leaving it in a dark place, then reducing excess ICI to iodine, and titrating the iodine content with sodium thiosulfate. The value (meq/g) obtained by converting the iodine value into a vinyl equivalent is referred to. In addition, the peroxide value in the present invention is a value obtained by adding potassium iodide to a sample, titrating the resulting free iodine with sodium thiosulfate, and converting this free iodine into milliequivalents per 1 kg of the sample (meq/ kg). The carbonyl value in the present invention is defined by reacting a sample with 2,4-dinitrophenylhydrazine to generate chromogenic alkynoid ions, measuring the absorbance of this sample at 480 nm, and preliminarily obtaining cinnamaldehyde as a standard substance. It refers to the value (mass ppm) converted to the amount of carbonyl based on the calibration curve obtained.

In the present embodiment, in order to obtain a polyalkylene glycol-based compound having a low degree of unsaturation, a low peroxide value and a low carbonyl value, the reaction temperature when reacting the alkylene oxide is preferably 120° C. or lower, and 110° C. or lower. is more preferable. In addition, if an alkali catalyst is used during production, use of an inorganic adsorbent (e.g., activated carbon, activated clay, bentonite, dolomite, aluminosilicate, etc.) to remove it will reduce the degree of unsaturation. be able to. In addition, the increase in peroxide value or carbonyl value can also be prevented by avoiding contact with oxygen as much as possible and adding an antioxidant when producing or using the polyalkylene glycol-based compound.

The polyvinyl ether-based compound is represented, for example, by the following general formula (1).

［式（１）中、Ｒ^１、Ｒ^２及びＲ^３は、互いに同一でも異なっていてもよく、それぞれ水素原子又は炭化水素基を示し、Ｒ^４は二価の炭化水素基又はエーテル結合酸素含有炭化水素基を示し、Ｒ^５は炭化水素基を示し、ｍは０以上の整数を示す。ｍが２以上である場合には、複数のＲ^４は互いに同一でも異なっていてもよい。］

[In formula (1), R ¹ , R ² and R ³ may be the same or different and each represents a hydrogen atom or a hydrocarbon group, and R ⁴ is a divalent hydrocarbon group or an ether-bonded oxygen-containing represents a hydrocarbon group, ^R5 represents a hydrocarbon group, and m represents an integer of 0 or more. When m is 2 or more, a plurality of ^R4 may be the same or different. ]

R ¹ to R ⁵ and m in the polyvinyl ether represented by formula (1) may be the same or different for each structural unit constituting the polyvinyl ether.

The number of carbon atoms in the hydrocarbon groups represented by R ¹ , R ² and R ³ in general formula (1) is preferably 1-8, more preferably 2-7, still more preferably 3-6. At least one of R ¹ , R ² and R ³ in formula (1) is preferably a hydrogen atom, more preferably all of them are hydrogen atoms.

The number of carbon atoms in the divalent hydrocarbon group and ether-bonded oxygen-containing hydrocarbon group represented by R ⁴ in general formula (1) is preferably 1 to 10, more preferably 2 to 8, and still more preferably 3 to 6. be. Further, the divalent ether-bonded oxygen-containing hydrocarbon group represented by R ⁴ in the general formula (1) may be, for example, a hydrocarbon group having an ether bond-forming oxygen in its side chain.

R ⁵ in general formula (1) is preferably a hydrocarbon group having 1 to 20 carbon atoms. Examples of the hydrocarbon group include alkyl groups, cycloalkyl groups, phenyl groups, aryl groups, and arylalkyl groups. Among these, an alkyl group is preferable, and an alkyl group having 1 to 5 carbon atoms is more preferable.

m in the general formula (1) is preferably 0 to 20, more preferably 1 to 18, even more preferably 2 to 16. The average value of m in all structural units constituting the polyvinyl ether is preferably 0-10.

The polyvinyl ether-based compound according to the present embodiment may be a homopolymer composed of one selected from the structural units represented by the general formula (1), and the structure represented by the general formula (1) It may be a copolymer composed of two or more selected from units, or a copolymer composed of a structural unit represented by the general formula (1) and another structural unit. By using polyvinyl ether as a copolymer, it is possible to further improve lubricating properties, insulating properties, hygroscopic properties, etc. while satisfying the compatibility with the refrigerant of the refrigerating machine oil. At this time, by appropriately selecting the type of monomers as raw materials, the type of initiator, the ratio of structural units in the copolymer, and the like, it is possible to obtain the desired characteristics of the refrigerating machine oil. Therefore, it is possible to freely obtain a refrigerating machine oil that meets different requirements such as lubricity and compatibility depending on the type of compressor in a refrigerating system or an air conditioning system, the material of lubricating parts, the refrigerating capacity, the type of refrigerant, and the like. The copolymer may be either a block copolymer or a random copolymer.

When the polyvinyl ether ^- based compound according to the present embodiment is a copolymer, the copolymer is a structural unit (1 -1), and a structural unit (1-2) represented by the above general formula (1) in which R ⁵ is an alkyl group having 3 to 20 carbon atoms, preferably 3 to 10 carbon atoms, more preferably 3 to 8 carbon atoms, is preferably included. Ethyl group is particularly preferred as R ⁵ in structural unit (1-1), and isobutyl group is particularly preferred as R ⁵ in structural unit (1-2). Furthermore, when the polyvinyl ether compound according to the present embodiment is a copolymer containing the above structural units (1-1) and (1-2), the structural unit (1-1) and the structural unit (1-2) ) is preferably from 5:95 to 95:5, more preferably from 20:80 to 90:10, even more preferably from 70:30 to 90:10. When the molar ratio is within the above range, the compatibility with the refrigerant can be further improved, and the hygroscopicity tends to be reduced.

The polyvinyl ether-based compound according to the present embodiment may be composed only of the structural unit represented by the general formula (1), but further includes the structural unit represented by the following general formula (2). It may be a copolymer containing In this case, the copolymer may be either a block copolymer or a random copolymer.

［式中、Ｒ^６～Ｒ^９は互いに同一でも異なっていてもよく、それぞれ水素原子又は炭素数１～２０の炭化水素基を示す。］

[In the formula, R ⁶ to R ⁹ may be the same or different, and each represents a hydrogen atom or a hydrocarbon group having 1 to 20 carbon atoms. ]

The polyvinyl ether-based compound according to the present embodiment is obtained by polymerizing a vinyl ether-based monomer corresponding to general formula (1), or It can be produced by copolymerization with a hydrocarbon monomer having a heavy bond. A monomer represented by the following general formula (3) is suitable as the vinyl ether monomer corresponding to the structural unit represented by the general formula (1).

［式中、Ｒ^１、Ｒ^２、Ｒ^３、Ｒ^４、Ｒ^５及びｍは、それぞれ一般式（１）中のＲ^１、Ｒ^２、Ｒ^３、Ｒ^４、Ｒ^５及びｍと同一の定義内容を示す。］

[In the formula, R ¹ , R ² , R ³ , R ⁴ , R ⁵ and m have the same definitions as R ¹ , R ² , R ³ , R ⁴ , R ⁵ and m in the general formula (1). Show content. ]

As the polyvinyl ether-based compound according to this embodiment, one having the following terminal structure (A) or (B) is suitable.

(A) Those having a structure in which one end is represented by general formula (4) or (5) and the other end is represented by general formula (6) or (7).

［式中、Ｒ^１１、Ｒ^２１及びＲ^３１は互いに同一でも異なっていてもよく、それぞれ水素原子又は炭素数１～８の炭化水素基を示し、Ｒ^４１は炭素数１～１０の二価の炭化水素基又は二価のエーテル結合酸素含有炭化水素基を示し、Ｒ^５１は炭素数１～２０の炭化水素基を示し、ｍは一般式（１）中のｍと同一の定義内容を示す。ｍが２以上の場合には、複数のＲ^４１は互いに同一でも異なっていてもよい。］

[ ^In the formula, R ¹¹ , R ²¹ and R ³¹ may be the same or different and each represents a hydrogen atom or a hydrocarbon group having 1 to 8 carbon atoms; represents a hydrocarbon group or a divalent ether-bonded oxygen-containing hydrocarbon group, R ⁵¹ represents a hydrocarbon group having 1 to 20 carbon atoms, and m has the same definition as m in formula (1). When m is 2 or more, multiple R ⁴¹ may be the same or different. ]

［式中、Ｒ^６１、Ｒ^７１、Ｒ^８１及びＲ^９１は互いに同一でも異なっていてもよく、それぞれ水素原子又は炭素数１～２０の炭化水素基を示す。］

[In the formula, R ⁶¹ , R ⁷¹ , R ⁸¹ and R ⁹¹ may be the same or different, and each represents a hydrogen atom or a hydrocarbon group having 1 to 20 carbon atoms. ]

［式中、Ｒ^１２、Ｒ^２２及びＲ^３２は互いに同一でも異なっていてもよく、それぞれ水素原子又は炭素数１～８の炭化水素基を示し、Ｒ^４２は炭素数１～１０の二価の炭化水素基又は二価のエーテル結合酸素含有炭化水素基を示し、Ｒ^５２は炭素数１～２０の炭化水素基を示し、ｍは一般式（１）中のｍと同一の定義内容を示す。ｍが２以上の場合には、複数のＲ^４１は同一でも異なっていてもよい。］

[ ^In the formula, R ¹² , R ²² and R ³² may be the same or different and each represents a hydrogen atom or a hydrocarbon group having 1 to 8 carbon atoms; represents a hydrocarbon group or a divalent ether-bonded oxygen-containing hydrocarbon group, R ⁵² represents a hydrocarbon group having 1 to 20 carbon atoms, and m has the same definition as m in formula (1). When m is 2 or more, multiple R ⁴¹ may be the same or different. ]

［式中、Ｒ^６２、Ｒ^７２、Ｒ^８２及びＲ^９２は互いに同一でも異なっていてもよく、それぞれ水素原子又は炭素数１～２０の炭化水素基を示す。］

[In the formula, R ⁶² , R ⁷² , R ⁸² and R ⁹² may be the same or different, and each represents a hydrogen atom or a hydrocarbon group having 1 to 20 carbon atoms. ]

(B) Those having a structure in which one end is represented by the above general formula (4) or (5) and the other end is represented by the following general formula (8).

［式中、Ｒ^１３、Ｒ^２３及びＲ^３３は互いに同一でも異なっていてもよく、それぞれ水素原子又は炭素数１～８の炭化水素基を示す。］

[In the formula, R ¹³ , R ²³ and R ³³ may be the same or different and each represents a hydrogen atom or a hydrocarbon group having 1 to 8 carbon atoms. ]

Among such polyvinyl ether compounds, the following (a), (b), (c), (d) and (e) are particularly suitable as the main component of the refrigerating machine oil according to the present embodiment. be.

(a) having a structure in which one end is represented by general formula (4) or (5) and the other end is represented by general formula (6) or (7), and R in general formula (1) ¹ , R ² and R ³ are all hydrogen atoms, m is an integer of 0 to 4, R ⁴ is a divalent hydrocarbon group having 2 to 4 carbon atoms, and R ⁵ is a hydrocarbon group having 1 to 20 carbon atoms. some stuff.

(b) A structure having only a structural unit represented by general formula (1), wherein one end is represented by general formula (4) and the other end is represented by general formula (6) wherein R ¹ , R ² and R ³ in general formula (1) are all hydrogen atoms, m is an integer of 0 to 4, R ⁴ is a divalent hydrocarbon group having 2 to 4 carbon atoms, R ⁵ is a hydrocarbon group having 1 to 20 carbon atoms.

(c) having one end represented by general formula (4) or (5) and the other end represented by general formula (8), wherein R ¹ and R ² in general formula (1) and R ³ are both hydrogen atoms, m is an integer of 0 to 4, R ⁴ is a divalent hydrocarbon group having 2 to 4 carbon atoms, and R ⁵ is a hydrocarbon group having 1 to 20 carbon atoms.

(d) A structure having only a structural unit represented by general formula (1), wherein one end is represented by general formula (5) and the other end is represented by general formula (8) wherein R ¹ , R ² and R ³ in general formula (1) are all hydrogen atoms, m is an integer of 0 to 4, R ⁴ is a divalent hydrocarbon group having 2 to 4 carbon atoms, R ⁵ is a hydrocarbon group having 1 to 20 carbon atoms.

(e) any one of (a), (b), (c) and (d) above, wherein R ⁵ in general formula (1) is a hydrocarbon group having 1 to 3 carbon atoms; and a structural unit in which R ⁵ is a hydrocarbon group having 3 to 20 carbon atoms.

Further, the number average molecular weight Mn of the polyvinyl ether-based compound according to the present embodiment is preferably 500 or more, more preferably 600 or more, still more preferably 1000 or more, preferably 4000 or less, more preferably 3000 or less, further preferably is 2000 or less, particularly preferably 1500 or less. When the number average molecular weight of the polyvinyl ether-based compound is at least the above lower limit, the lubricity tends to improve, particularly in the presence of a mildly flammable hydrofluorocarbon refrigerant. On the other hand, when the number average molecular weight of the polyvinyl ether compound is equal to or less than the above upper limit, the compatibility with the refrigerant tends to be improved, and the compatibility with the mildly flammable hydrofluorocarbon refrigerant is improved especially under low temperature conditions. In addition to widening the composition range, it tends to be possible to suppress poor lubrication of the refrigerant compressor and inhibition of heat exchange in the evaporator.

In the polyvinyl ether compound according to the present embodiment, the ratio Mw/Mn between the weight average molecular weight Mw and the number average molecular weight Mn is not particularly limited, but is usually 1.0 or more and 3.0 or less, preferably 1 .1 or more, more preferably 1.15 or more, preferably 2.5 or less, more preferably 2.0 or less, more preferably 1.5 or less, more preferably 1.35 or less, still more preferably It is 1.3 or less, particularly preferably 1.25 or less. However, in the polyvinyl ether-based compound according to the present invention, even if Mw / Mn is more than 1.25 and 3.0 or less, by blending the amine-based compound of the present invention, refrigerating machine oil with a high spontaneous ignition point can be obtained.

The Mw, Mn and Mw/Mn of the polyvinyl ether compound according to the present embodiment mean the Mw, Mn and Mw/Mn (polystyrene (standard sample) conversion values) obtained by GPC analysis. Mw, Mn and Mw/Mn can be measured, for example, as follows.

Using chloroform as a solvent, a diluted solution with a sample concentration of 2% by mass is prepared and analyzed using a GPC device (Waters, Alliance 2695). The solvent flow rate is set to 1 ml/min, the analysis is performed using a column with an analyzable molecular weight of 100 to 10,000, and the refractive index as a detector. The relationship between the column retention time and the molecular weight is determined using a polystyrene standard with a definite molecular weight, a calibration curve is prepared separately, and the molecular weight is determined from the obtained retention time.

In addition, the weight average molecular weight Mw of the polyvinyl ether-based compound according to the present embodiment may be appropriately selected so that Mn and Mw/Mn satisfy the above conditions.

The flash point of the polyvinyl ether-based compound according to this embodiment is preferably 195° C. or higher, more preferably 200° C. or higher, and even more preferably 205° C. or higher.

The higher the spontaneous ignition point of the polyvinyl ether-based compound according to the present embodiment, the easier it is to ensure safety. It is 450° C. or lower, more preferably 420° C. or lower, still more preferably 400° C. or lower. The spontaneous ignition point of the polyvinyl ether compound is preferably 320°C or higher, more preferably 335°C or higher, even more preferably 340°C or higher, and particularly preferably 345°C or higher.

The kinematic viscosity at 100° C. of the polyvinyl ether compound according to the present embodiment is preferably 6.5 to 9.5 mm ² /s, more preferably 7.0 to 9.0 mm ² /s, still more preferably 7.5. ˜8.5 mm ² /s. When the kinematic viscosity at 100°C is equal to or higher than the above lower limit, the lubricity in the coexistence of a refrigerant is improved. On the other hand, when the kinematic viscosity at 100° C. is equal to or less than the above upper limit, the range of composition exhibiting compatibility with the refrigerant is widened, and poor lubrication of the refrigerant compressor and inhibition of heat exchange in the evaporator can be suppressed.

The kinematic viscosity at 40° C. of the polyvinyl ether compound according to this embodiment is preferably 50 to 80 mm ² /s, more preferably 55 to 75 mm ² /s, still more preferably 60 to 70 mm ² /s. When the kinematic viscosity at 40°C is equal to or higher than the above lower limit, there is a tendency that the lubricity and the airtightness of the compressor are improved. On the other hand, if the kinematic viscosity at 40°C is equal to or less than the above upper limit, the composition range that exhibits compatibility with the refrigerant under low temperature conditions is widened, and poor lubrication of the refrigerant compressor and inhibition of heat exchange in the evaporator are suppressed. can.

The pour point of the polyvinyl ether compound according to the present embodiment is preferably -10°C or less, more preferably -20 to -50°C. The use of a polyvinyl ether compound having a pour point of -10°C or less tends to suppress solidification of refrigerating machine oil in the refrigerant circulation system at low temperatures.

The polyvinyl ether-based compound according to the present embodiment can be produced by subjecting the above-described monomers to radical polymerization, cationic polymerization, radiation polymerization, or the like. After the completion of the polymerization reaction, the desired polyvinyl ether compound having the structural unit represented by the general formula (1) can be obtained by subjecting it to a normal separation/purification method as necessary.

In the production process of the polyvinyl ether-based compound according to the present embodiment, a side reaction may occur to form an unsaturated group such as an aryl group in the molecule. From the viewpoint of suppressing the generation of sludge due to the generation of and suppressing the generation of peroxides due to a decrease in antioxidant properties (antioxidant properties), the polyvinyl ether-based compound according to the present embodiment is derived from an unsaturated group or the like. Those with a low degree of unsaturation are preferred. The degree of unsaturation of the polyvinyl ether compound is preferably 0.04 meq/g or less, more preferably 0.03 meq/g or less, and even more preferably 0.02 meq/g or less. Moreover, the peroxide value of the polyvinyl ether compound is preferably 10.0 meq/kg or less, more preferably 5.0 meq/kg or less, and even more preferably 1.0 meq/kg. The carbonyl value of the polyvinyl ether compound is preferably 100 ppm by weight or less, more preferably 50 ppm by weight or less, and even more preferably 20 ppm by weight or less. Moreover, the hydroxyl value of the polyvinyl ether compound is preferably 10 mgKOH/g or less, more preferably 5 mgKOH/g or less, and even more preferably 3 mgKOH/g or less.

The oil or oil composition according to the present embodiment contains the above ether-based compound as a base oil, but may also contain a base oil other than the ether-based compound described below, if necessary. The content of the ether-based compound according to the present embodiment is preferably 50% by mass or more, more preferably 70% by mass or more, and 80% by mass or more, based on the total amount of the oil or oil composition. More preferably, it is particularly preferably contained in an amount of 90% by mass or more. When the content of the ether-based compound is 50% by mass or more, the safety of the refrigerating machine oil can be further enhanced by the addition of the amine-based compound described later.

Examples of base oils other than ether-based compounds according to the present embodiment include mineral oils, olefin polymers, naphthalene compounds, hydrocarbon-based oils such as alkylbenzene, ester-based base oils (monoesters, diesters, polyol esters, etc.), poly Oxygen-containing synthetic oils such as glycols, ketones, polyphenylethers, silicones, polysiloxanes, and perfluoroethers can be used. A polyol ester is preferably used as the oxygen-containing synthetic oil.

The oils according to the present embodiment contain the base oil described above, but in order to further improve the performance of the refrigerating machine oil, in addition to the base oil described above, conventionally known compounds other than the amine-based compound described later as necessary A lubricating oil additive can be contained to form an oil composition. Examples of such additives include antioxidants other than amine compounds, acid scavengers, antiwear agents, extreme pressure agents, oiliness agents, antifoaming agents, metal deactivators, viscosity index improvers, and pour point depressants. agents, detergent dispersants, and the like. These additives may be used singly or in combination of two or more.

Anti-wear agents include phosphorus-based anti-wear agents such as orthophosphates such as tricresyl phosphate and triphenyl phosphate, phosphites, acidic phosphates and their amine salts, and sulfur-based anti-wear agents. and at least one antiwear agent selected from phosphorus-sulfur antiwear agents.

Examples of acid scavengers include at least one acid scavenger selected from glycidyl esters, glycidyl ethers, α-olefin oxides, carbodiimides and the like.

Although the content of these additives is not particularly limited, it is preferably 10% by mass or less, more preferably 5% by mass or less, based on the total amount of the oil composition.

The higher the autoignition point of the oil or oil composition according to the present embodiment, the easier it is to ensure safety, but from the viewpoint of more effectively increasing the autoignition point by adding an amine compound described later. , preferably 450° C. or lower, more preferably 420° C. or lower, and still more preferably 400° C. or lower. In addition, the spontaneous ignition point of the oil or oil composition is preferably 320°C or higher, more preferably 340°C or higher, and still more preferably 350°C or higher.

As the amine compound added to the oil or oil composition according to the present embodiment, phenyl-α-naphthylamines represented by the following general formula (24), or p, p'- and dialkylated diphenylamine.

In general formula (24), R ⁵⁸ represents a hydrogen atom or an alkyl group having 1 to 16 carbon atoms. In general formula (25), R ⁵⁹ and R ⁶⁰ each independently represent an alkyl group having 1 to 16 carbon atoms. The alkyl group having 1 to 16 carbon atoms is preferably a branched alkyl group having 8 to 16 carbon atoms, more preferably a branched alkyl group having 8 to 16 carbon atoms derived from an olefin oligomer having 3 or 4 carbon atoms. . Specific examples of olefins having 3 or 4 carbon atoms include at least one selected from the group consisting of propylene, 1-butene, 2-butene and isobutylene, preferably propylene or isobutylene. R ⁵⁸ is a branched octyl group derived from a dimer of isobutylene, a branched nonyl group derived from a trimer of propylene, a branched dodecyl group derived from a trimer of isobutylene, a branched dodecyl group derived from a trimer of propylene, It may be a branched dodecyl group derived from a tetramer, a branched pentadecyl group derived from a propylene pentamer, a branched octyl group derived from an isobutylene dimer, or an isobutylene trimer. or a branched dodecyl group derived from a propylene tetramer, or a branched dodecyl group.

Among the compounds represented by the general formula (24), the case where R ⁵⁸ is a hydrogen atom is preferable because a more excellent effect of improving the spontaneous ignition point can be obtained.

R ⁵⁹ and R ⁶⁰ of the p,p'-dialkyldiphenylamine represented by the general formula (25) may each independently be a branched alkyl group having 3 to 16 carbon atoms, or It may be a branched alkyl group having 3 to 16 carbon atoms derived from an olefin or an oligomer thereof. Specific examples of the olefin having 3 or 4 carbon atoms include propylene, 1-butene, 2-butene and isobutylene, but propylene or isobutylene may also be used. Furthermore, R ⁵⁹ or R ⁶⁰ may be a tert-butyl group derived from isobutylene or a branched octyl group derived from a dimer of isobutylene.

As the p,p'-dialkyldiphenylamine represented by the general formula (25), commercially available products or synthesized products may be used. Similar to the phenyl-α-naphthylamine represented by the general formula (24), the synthesized product is a C 1-16 halogenated alkyl compound and diphenylamine, or a C 2-16 olefin or a C 2-16 It can be easily synthesized by reacting an olefin or an oligomer thereof with diphenylamine using a Friedel-Crafts catalyst, but any synthesis method may be used.

The content of the amine compound is preferably 0.1% by mass or more, more preferably 0.4% by mass or more, still more preferably 0.8% by mass or more, and preferably 10% by mass, based on the total amount of refrigerating machine oil. 6% by mass or less, more preferably 6% by mass or less. In particular, from the viewpoint of being able to raise the spontaneous ignition point, it is more preferably 1.2% by mass or more, still more preferably 2.5% by mass or more, and particularly preferably 4% by mass or more. If the content of the amine antioxidant is 10% by mass or less based on the total amount of refrigerating machine oil, the cause of sludge generation can be suppressed, and if it is 0.1% by mass or more, the spontaneous ignition point is effectively increased. be able to.

By adding an amine-based compound to the oil or oil composition described above, a refrigerating machine oil having improved ignition resistance can be obtained. That is, the refrigerator oil according to the present embodiment includes a base oil containing an ether compound and an amine compound.

The kinematic viscosity of the refrigerator oil at 40° C. is not particularly limited, but is preferably 3 to 1000 mm ² /s, more preferably 4 to 500 mm ² /s, still more preferably 5 to 400 mm ² /s. Also, the kinematic viscosity at 100° C. is preferably 1 to 100 mm ² /s, more preferably 2 to 50 mm ² /s.

The water content of the refrigerator oil is not particularly limited, but is preferably 500 ppm or less, more preferably 300 ppm or less, and still more preferably 200 ppm or less based on the total amount of the refrigerator oil. In particular, when used for a closed-type refrigerator, the water content is required to be small from the viewpoint of the influence on the thermal and chemical stability and electrical insulation of the refrigerator oil.

In addition, the acid value of the refrigerating machine oil of the present embodiment is not particularly limited. , preferably 0.1 mgKOH/g or less, more preferably 0.05 mgKOH/g or less. The acid value in the present invention means an acid value measured according to JIS K2501 "Petroleum products and lubricating oils-neutralization value test method".

The ash content of the refrigerator oil is not particularly limited, but is preferably 100 ppm or less, more preferably 50 ppm or less, in order to improve the thermal and chemical stability of the refrigerator oil and suppress the generation of sludge and the like. The ash content in the present invention means the value of ash content measured according to JIS K2272 "Determination of ash content and sulfated ash content of crude oil and petroleum products".

Refrigerating machine oil usually exists in a refrigerator or the like in the form of a working fluid composition for a refrigerating machine in which refrigerating machine oil and refrigerant are mixed. In other words, the working fluid composition for refrigerator contains refrigerator oil and refrigerant. The refrigerating machine oil according to the present embodiment is preferably used with a mildly flammable refrigerant, more preferably with a slightly flammable hydrofluorocarbon (HFC) refrigerant. That is, the working fluid composition for a refrigerator of the present embodiment preferably contains a mildly flammable refrigerant, more preferably a slightly flammable hydrofluorocarbon (HFC) refrigerant. Hydrofluorocarbon (HFC) refrigerants include saturated fluorocarbon refrigerants (also called hydrofluoroalkane refrigerants) and unsaturated fluorocarbon refrigerants (also called hydrofluoroalkene refrigerants, hydrofluoroolefin refrigerants, or HFO refrigerants). be done. The mildly flammable refrigerant in the present invention means a refrigerant included in the A2L category in the flammability category of ASHRAE (The American Society of Heating, Refrigerating and Air-conditioning Engineers) 34.

Saturated fluorocarbon refrigerants include saturated fluorohydrocarbons having 1 to 3 carbon atoms, preferably 1 to 2 carbon atoms. Specifically, for example, difluoromethane (HFC-32), trifluoromethane (HFC-23), pentafluoroethane (HFC-125), 1,1,2,2-tetrafluoroethane (HFC-134), 1 , 1,1,2-tetrafluoroethane (HFC-134a), 1,1,1-trifluoroethane (HFC-143a), 1,1-difluoroethane (HFC-152a), fluoroethane (HFC-161), 1,1,1,2,3,3,3-heptafluoropropane (HFC-227ea), 1,1,1,2,3,3-hexafluoropropane (HFC-236ea), 1,1,1, 3,3,3-hexafluoropropane (HFC-236fa), 1,1,1,3,3-pentafluoropropane (HFC-245fa), 1,1,1,3,3-pentafluorobutane (HFC- 365mfc), and mixtures of two or more thereof. These refrigerants are appropriately selected depending on the application and required performance, but for example, HFC-32 alone; HFC-23 alone; HFC-134a alone; HFC-125 alone; % by mass/mixture of 40-20% by mass; HFC-32/HFC-125=40-70% by mass/mixture of 60-30% by mass; HFC-125/HFC-143a=40-60% by mass/60-40 % mixture; HFC-134a/HFC-32/HFC-125 = 60%/30%/10% mixture; HFC-134a/HFC-32/HFC-125 = 40 to 70%/15 Preferred examples include a mixture of ~35% by mass/5 to 40% by mass; a mixture of HFC-125/HFC-134a/HFC-143a = 35 to 55% by mass/1 to 15% by mass/40 to 60% by mass. be done. More specifically, HFC-134a/HFC-32 = 70/30 mass% mixture; HFC-32/HFC-125 = 60/40 mass% mixture; HFC-32/HFC-125 = 50/50 mass% % mixture (R410A); HFC-32/HFC-125 = 45/55% by weight mixture (R410B); HFC-125/HFC-143a = 50/50% by weight mixture (R507C); HFC-32/HFC -125/HFC-134a = 30/10/60 wt% mixture; HFC-32/HFC-125/HFC-134a = 23/25/52 wt% mixture (R407C); HFC-32/HFC-125/ HFC-134a = 25/15/60 mass% mixture (R407E); HFC-125/HFC-134a/HFC-143a = 44/4/52 mass% mixture (R404A).

Among the above saturated fluorocarbons, difluoromethane (HFC-32), pentafluoroethane (HFC-125), 1,1,2,2-tetrafluoroethane (HFC-134), 1,1,1, 2-tetrafluoroethane (HFC-134a), 1,1-difluoroethane (HFC-152a), fluoroethane (HFC-161), 1,1,1,2,3,3,3-heptafluoropropane (HFC- 227ea), 1,1,1,2,3,3-hexafluoropropane (HFC-236ea), 1,1,1,3,3,3-hexafluoropropane (HFC-236fa), 1,1,1 , 3,3-pentafluoropropane (HFC-245fa) and 1,1,1,3,3-pentafluorobutane (HFC-365mfc), or a mixture of two or more selected from the group consisting of and more preferably HFC-32, HFC-125, HFC-134a, HFC-152a, or a mixture of HFC-32 and HFC-134a from the viewpoint of refrigerant physical properties.

As the unsaturated fluorocarbon, fluoropropene having 3 to 5 fluorine atoms is preferable, and 1,2,3,3,3-pentafluoropropene (HFC-1225ye), 1,3,3,3-tetrafluoro Propene (HFC-1234ze), 2,3,3,3-tetrafluoropropene (HFC-1234yf), 1,2,3,3-tetrafluoropropene (HFC-1234ye), and 3,3,3-trifluoro It is preferably one or a mixture of two or more selected from the group consisting of propene (HFC-1243zf). From the viewpoint of refrigerant physical properties, it is preferably one or more selected from HFC-1225ye, HFC-1234ze and HFC-1234yf.

As the slightly flammable hydrofluorocarbon refrigerant, 1,3,3,3-tetrafluoropropene or 2,3,3,3-tetrafluoropropene is particularly preferred.

The refrigerant used together with the refrigerating machine oil of the present embodiment may be, for example, a mixed refrigerant of a mildly flammable hydrofluorocarbon refrigerant and another refrigerant. Other refrigerants include fluorine-containing ether refrigerants such as perfluoroethers, bis(trifluoromethyl)sulfide refrigerants, trifluoroiodide methane refrigerants, natural refrigerants such as dimethyl ether, carbon dioxide, ammonia and hydrocarbons. mentioned.

Hydrocarbon refrigerants are preferably hydrocarbons having 3 to 5 carbon atoms, and specific examples include methane, ethylene, ethane, propylene, propane, cyclopropane, normal butane, isobutane, cyclobutane, methylcyclopropane, and 2-methylbutane. , normal pentane, or a mixture of two or more thereof. Among these, those that are gaseous at 25° C. and 1 atm are preferably used, and propane, normal butane, isobutane, 2-methylbutane and mixtures thereof are preferred.

Specific examples of fluorine-containing ether refrigerants include HFE-134p, HFE-245mc, HFE-236mf, HFE-236me, HFE-338mcf, HFE-365mcf, HFE-245mf, HFE-347mmy, HFE-347mcc, HFE-125, HFE-143m, HFE-134m, HFE-227me and the like are listed, and these refrigerants are appropriately selected according to the application and required performance.

Further, when the refrigerant of the present embodiment is a mixed refrigerant, the mixing ratio (mass ratio, slightly flammable hydrofluorocarbon refrigerant:other refrigerant) of the slightly flammable hydrofluorocarbon refrigerant and the other refrigerant is 1:99 to 99. :1 is preferred, and 5:95 to 95:5 is more preferred.

The blending ratio of the refrigerator oil and the refrigerant in the working fluid composition for a refrigerator of the present embodiment is not particularly limited, but the refrigerator oil is preferably 1 to 500 parts by mass, more preferably 2 to 400 parts by mass with respect to 100 parts by mass of the refrigerant. part by mass.

The refrigerating machine oil of the present embodiment is preferably used in air conditioners, refrigerators, and open or closed car air conditioners having a reciprocating or rotary hermetic compressor. In addition, the refrigerating machine oil and the working fluid composition for a refrigerating machine of the present embodiment are preferably used for cooling devices such as dehumidifiers, water heaters, freezers, refrigerated warehouses, vending machines, showcases, and chemical plants. Furthermore, the refrigerating machine oil of the present embodiment is preferably used for those having a centrifugal compressor.

EXAMPLES The present invention will be described in more detail below based on examples, but the present invention is not limited to the following examples.

[Examples 1 to 5]
First, base oils 1 to 5 shown below and each additive were used to prepare an oil composition, and the spontaneous ignition point of the obtained oil composition was measured. Thereafter, phenyl-α-naphthylamine was added as an amine compound to prepare a refrigerating machine oil, and the autoignition point of the obtained refrigerating machine oil was measured. The spontaneous ignition point was measured according to ASTM E659-1978. Table 1 shows the compositions of the oils and the refrigerating machine oil, and the measurement results of the autoignition points.

(base oil)
Hereinafter, Me represents a methyl group, Bu represents a butyl group, and PO represents an oxypropylene group.

Base oil 1:
Me—O—(PO)n—Me
[Number average molecular weight Mn: 1240, ratio of weight average molecular weight (Mw) to number average molecular weight (Mn) (Mw/Mn): 1.1, 40°C kinematic viscosity: 50.5 mm ² /s, flash point: 218 ℃, hydroxyl value: 6.8 mgKOH / g, pour point: <-45 ℃, acid value: 0.01 mgKOH / g

Base oil 2:
Bu-O-(PO)n-Bu
[Number average molecular weight Mn: 1290, ratio of weight average molecular weight (Mw) to number average molecular weight (Mn) (Mw/Mn): 1.11, 40°C kinematic viscosity: 56 mm ² /s, flash point: 220°C ( COC), pour point: -42.5 ° C., acid value: 0.01 mgKOH / g

Base oil 3:
Bu-O-(PO)n-Bu
[Number average molecular weight Mn: 1440, ratio of weight average molecular weight (Mw) to number average molecular weight (Mn) (Mw/Mn): 1.16, 40°C kinematic viscosity: 68 mm ² /s, flash point: 220°C ( COC), pour point: -40°C, acid value: 0.01mgKOH/g

Base oil 4:
Bu-O-(PO)n-Bu
[Number average molecular weight Mn: 1640, ratio of weight average molecular weight (Mw) to number average molecular weight (Mn) (Mw/Mn): 1.20, 40°C kinematic viscosity: 100 mm ² /s, flash point: 222°C ( COC), pour point: -35 ° C., acid value: 0.01 mg KOH / g

Base oil 5:
Bu-O-(PO)n-Bu
[Number average molecular weight Mn: 2250, ratio of weight average molecular weight (Mw) to number average molecular weight (Mn) (Mw/Mn): 1.28, 40°C kinematic viscosity: 200 mm ² /s, flash point: 222°C ( COC), pour point: -30°C, acid value: 0.01mgKOH/g

(Additive)
Additive 1: tricresyl phosphate (antiwear agent)
Additive 2: glycidyl neodecanoate (acid scavenger)

[Examples 6 to 10]
Oil compositions were prepared using base oils 6 to 8 shown below and each additive, and the autoignition point of the obtained oil compositions was measured. Thereafter, phenyl-α-naphthylamine was added as an amine compound to prepare a refrigerating machine oil, and the autoignition point of the obtained refrigerating machine oil was measured. Table 2 shows the compositions of the oils and the refrigerating machine oil, and the measurement results of the autoignition points.

(base oil)
Base oil 6:
Copolymer of ethyl vinyl ether and isobutyl vinyl ether [ethyl vinyl ether/isobutyl vinyl ether = 8/2 (molar ratio), number average molecular weight (Mn): 500, ratio of weight average molecular weight (Mw) to number average molecular weight (Mn) (Mw/Mn): 1.25, 40°C kinematic viscosity: 50 mm ² /s, viscosity index 91]

Base oil 7:
Ethyl vinyl ether polymer [number average molecular weight (Mn): 1300, ratio of weight average molecular weight (Mw) to number average molecular weight (Mn) (Mw/Mn): 1.20, 40°C kinematic viscosity: 68 mm ² /s, Viscosity index: 90]

Base oil 8:
Ethyl vinyl ether polymer [number average molecular weight (Mn): 1300, ratio of weight average molecular weight (Mw) to number average molecular weight (Mn) (Mw/Mn): 1.29, 40°C kinematic viscosity: 71 mm ² /s, Viscosity index: 89]

(Additive)
Additive 1: tricresyl phosphate (antiwear agent)
Additive 2: glycidyl neodecanoate (acid scavenger)

Claims (6)

A method for improving the ignition resistance of a refrigerating machine oil, comprising the step of adding an amine compound to an oil or oil composition containing a base oil containing an ether compound to obtain a refrigerating machine oil ,
The method, wherein the ether-based compound is a polyvinyl ether-based compound, and the ratio Mw/Mn of the weight-average molecular weight Mw to the number-average molecular weight Mn of the polyvinyl ether-based compound is 1.25 or less . 2. The method according to claim 1 , wherein the ratio Mw/Mn between the weight average molecular weight Mw and the number average molecular weight Mn of the polyvinyl ether compound is 1.15 or more . The refrigerating machine oil contains an antiwear agent, an acid scavenger, an antioxidant other than the amine compound, an extreme pressure agent, an oiliness agent, an antifoaming agent, a metal deactivator, a viscosity index improver, a pour point depressant, 3. The method of claim 1 or 2 , further comprising at least one additive selected from the group consisting of detergent-dispersants. The method according to any one of claims 1 to 3 , wherein the refrigerating machine oil is used together with a mildly flammable refrigerant. A refrigerating machine oil with improved ignition resistance, containing a base oil containing an ether-based compound and an amine-based compound,
Refrigerating machine oil, wherein the ether-based compound is a polyvinyl ether-based compound, and the ratio Mw/Mn between the weight average molecular weight Mw and the number average molecular weight Mn of the polyvinyl ether-based compound is 1.25 or less . 6. The refrigerating machine oil according to claim 5, wherein the polyvinyl ether compound has a weight average molecular weight Mw to number average molecular weight Mn ratio Mw/Mn of 1.15 or more.