JPH06122888A - Lubricating oil for refrigerator - Google Patents

Abstract

PURPOSE:To obtain the subject thermally and chemically stable product which is a lubricating oil for a refrigerator using a hydrogen-containing halogenated hydrocarbon as a refrigerant, comprising a specific fumaric acid ester polymer and excellent in compatibility with the refrigerant and lubricity. CONSTITUTION:The objective product comprises a fumaric acid ester polymer of the formula [R1 and R2 are 1-9C linear or branched alkyl, allyl, etc.; R3 is alkylene, alkylene oxide, etc.; (m) is >=0; (n) is >=1, with the proviso that the content of R3 is <=50mol% based on the whole]. The polymer of the formula is preferably obtained by polymerizing a fumaric aid ester in the presence of a polymerization initiator according to thermal refluxing or copolymerizing the fumaric acid ester with an unsaturated aliphatic hydrocarbon such as butadiene in the presence of the polymerization initiator in an autoclave by heating and stirring the reactional mixture. Furthermore, the polymer of the formula has preferably 400-1600 molecular weight.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a refrigerating machine lubricating oil using a hydrogen-containing halogenated hydrocarbon, and more particularly to a novel refrigerating machine lubricating oil having excellent compatibility with a refrigerant and excellent lubricity. .

[0002]

2. Description of the Related Art Conventionally, as a refrigerant for a refrigerator, R11 (CCl ₃ F) is mainly used for an air conditioner such as a building, and R12 (CC
l ₂ F ₂ ) is used as a refrigerant for refrigerators for car air conditioners such as electric refrigerators, rotary type and reciprocating type, but ozone depletion in the stratosphere has recently become a social problem, and the development of alternative CFCs has become urgent. .

Recently, as an alternative to R11, R123 (CF ₃ CHC
l ₂ ), but R22 (CHClF ₂ ) and R134a are alternatives to R12.
The use of (CF ₃ CH ₂ F, 1.1.1.2-tetrafluoroethane) is beginning to be noticed.

[0004]

Lubricating oils for refrigerating machines generally have a wide compatibility temperature range with the refrigerant (compatibility), that is, no fog at high temperatures (solvent solvability of the refrigerant with respect to the lubricating oil). Large), the molecular polarity of the lubricating oil is large, there is no precipitation of the lubricating oil at low temperature (the solubility of the lubricating oil in the refrigerant is large, and the molecular weight of the lubricating base oil is small). In addition, various refrigerators are required to have different suitable viscosity ranges and have corresponding viscosities and flash points.

The present invention is directed to hydrogen-containing halogenated hydrocarbons such as R22 (CHClF ₂ ), R123 (CF ₃ CHCl ₂ ), R141b (C
Cl ₂ FCH ₃ ), in particular, non-chlorine halogenated hydrocarbons, such as R134a (CF ₃ CH ₂ F), R152a (CHF ₂ CH ₃ ), etc. To do.

[0006]

The lubricating oil for a refrigerator of the present invention is a lubricating oil for a refrigerator using a hydrogen-containing halogenated hydrocarbon, and is fumaric acid represented by the following general formula [Chemical Formula 3]. It is characterized by containing an ester polymer.

The refrigerating machine lubricating oil of the present invention is a refrigerating machine lubricating oil using a hydrogen-containing halogenated hydrocarbon, and comprises a fumaric acid ester polymer represented by the following general formula [Chemical Formula 3]. , Viscosity range at 100 ℃ is 2mm ² / s ~ 30mm
It is characterized by comprising an organic carboxylic acid ester of ² / s or a polyalkylene glycol.

Furthermore, the refrigerator lubricating oil of the present invention is characterized in that a viscosity index improver is further added to each of the above refrigerator lubricating oils.

[0009]

[Chemical 3]

(In the formula, R ₁ and R ₂ are a linear or branched alkyl group having 1 to 9 carbon atoms, an allyl group or a terminal substituted or unsubstituted polyalkylene oxide group, which may be the same or different. R ₃ is an alkylene group, a substituted alkylene group or an alkylene oxide group, m is 0 or more, n is 1 or more, preferably an integer of 1 to 12, and R ₃ is 50 mol% or less of the whole) Hereinafter, the refrigerator lubricating oil of the present invention will be described.

The fumarate ester polymer represented by the above [Chemical Formula 3], which is a lubricating oil for refrigerators, is a homopolymer of a fumarate ester or a copolymer of a fumarate ester and an unsaturated aliphatic hydrocarbon. Both terminals in the above [Chemical Formula 3] are a polymerization initiator residue used in the polymerization reaction, and the description thereof is omitted in the formula.

The fumarate ester homopolymer (that is, when m in the above [Chemical Formula 3] is 0) is obtained by heating and refluxing the fumarate ester in the presence of a polymerization initiator. Further, the fumarate ester copolymer (that is, when m in the above [Chemical Formula 3] is not 0) is obtained by adding the fumarate ester and an unsaturated aliphatic hydrocarbon such as butadiene in an autoclave in the presence of a polymerization initiator. It is obtained by polymerizing with heating and stirring, and the proportion of unsaturated aliphatic hydrocarbons in the copolymer is preferably 50 mol% or less. When an unsaturated aliphatic hydrocarbon is copolymerized with the fumarate, the viscosity index can be further improved, but if it is 50 mol% or more, the compatibility with the refrigerant is deteriorated, which is not preferable.

The polymerization initiator used in the polymerization reaction is an azo compound such as an azonitrile compound, an azoamidine compound, a cyclic azoamidine compound, an azoamide compound or an alkylazo compound, a ketone peroxide, a peroxyketal, a hydroperoxide or a dialkylperoxide. Peroxides such as oxides, diacyl peroxides, diperoxydicarbonates, and peroxyesters are used.

In these fumaric acid ester polymers of the present invention, R ₁ and R ₂ are linear or branched alkyl groups having 1 to 9 carbon atoms, allyl groups, or terminal-substituted or unsubstituted polyalkylene oxide groups [generally Represented by the formula:-(AO) _n- X, X is hydrogen or an alkyl group having 1 to 4 carbon atoms, A
Is an ethylene, propylene, butylene group, n is an integer of 1 to 5, and examples thereof include a carbitol and a ceritol group.] It is preferably one having 4 to 6 carbon atoms and having a large number of carbon atoms, The compatibility with the refrigerant deteriorates.

The degree of polymerization of the fumaric acid ester polymer is adjusted so as to have an appropriate viscosity as a lubricating oil for a refrigerator, which will be described later, but the molecular weight of the lubricating oil for a refrigerator is 4
It is good to set it as 00-2000, Preferably it is 400-16
At a viscosity of 2 mm ² / s to 100 mm ² / s (100 ° C)
Is the range. When the molecular weight is large, the effect of improving the viscosity index is excellent, but it is not preferable because it becomes solid at room temperature and the compatibility with the refrigerant deteriorates.

The fumaric acid ester polymers may be used as a mixture of polymers having different molecular weights. Furthermore, in order to improve the viscosity and viscosity index of the low molecular weight fumaric acid ester polymer, it is advisable to add a fumaric acid ester polymer having a molecular weight of 3,000 to 10,000.

Further, generally, those commonly used as a viscosity index improver have poor compatibility with a refrigerant and have a problem in addition to a lubricating oil for a refrigerator, but a fumarate polymer is not compatible with a refrigerant. Since it has excellent compatibility and is excellent as a viscosity index improver, it is also useful as a viscosity index improver when an organic carboxylic acid ester is used as a base oil of a lubricating oil for a refrigerator, and a fumaric acid ester polymer. When used as a refrigerating machine lubricating oil, for the purpose of adjusting its viscosity and viscosity index for various refrigerating machines, for example, normal refrigerating machine lubricating oils such as organic carboxylic acid esters, polyalkylene glycols, alkylbenzenes and mineral oils. The oils can be mixed and used in the desired proportions.

Organic carboxylic acid esters are preferable, and the following ones having high molecular polarity are used.

(1) First, polyesters of an aliphatic polyhydric alcohol and a linear or branched fatty acid can be used.

Examples of the aliphatic polyhydric alcohol forming the polyesters include trimethylolpropane, ditrimethylolpropane, trimethylolethane, ditrimethylolethane, pentaerythritol, dipentaerythritol, tripentaerythritol, and the like fatty acid. Can have 3 to 12 carbon atoms, preferred fatty acids are propionic acid, butyric acid, valeric acid,
Hexanoic acid, octanoic acid, nonanoic acid, decanoic acid, dodecanoic acid, isovaleric acid, neopentanoic acid, 2-methylbutyric acid,
2-ethylbutyric acid, 2-methylhexanoic acid, 2-ethylhexanoic acid, isooctanoic acid, isononanoic acid, isodecanoic acid, 2,2'-dimethyloctanoic acid, 2-butyloctanoic acid and the like.

Further, partial esters of an aliphatic polyhydric alcohol and a linear or branched fatty acid can also be used.

As the aliphatic polyhydric alcohol, trimethylolpropane, ditrimethylolpropane, trimethylolethane, ditrimethylolethane, pentaerythritol, dipentaerythritol, tripentaerythritol and the like can be used. Fatty acids having 3 to 9 carbon atoms, such as propionic acid, butyric acid, valeric acid,
Hexanoic acid, heptanoic acid, octanoic acid, nonanoic acid, 2-
Methylhexanoic acid, 2-ethylhexanoic acid, isooctanoic acid, isononanoic acid, isodecanoic acid, 2,2'-dimethyloctanoic acid, 2-butyloctanoic acid and the like.

As the esters of these aliphatic polyhydric alcohols with linear or branched fatty acids, pentaerythritol, dipentaerythritol, tripentaerythritol and 5 to 12 carbon atoms, more preferably 5 carbon atoms, are preferred. ~ 7 fatty acids, such as valeric acid, hexanoic acid, heptanoic acid, 2-methylhexanoic acid, 2-ethylhexanoic acid, isooctanoic acid, isononanoic acid, isodecanoic acid, 2,2 '
-The ester oil formed by dimethyloctanoic acid, 2-butyloctanoic acid, or a mixture thereof can improve the compatibility with the refrigerant particularly at low temperatures.

These partial esters can be obtained by appropriately adjusting the number of moles of the reaction between the aliphatic polyhydric alcohol and the fatty acid to carry out the reaction.

(2) Neopentyl glycol as an aliphatic polyhydric alcohol and a linear or branched fatty acid having 6 to 9 carbon atoms such as hexanoic acid, heptanoic acid, octanoic acid, nonanoic acid, 2-ethylbutyric acid It is also possible to use diesters with 2-methylhexanoic acid, 2-ethylhexanoic acid, isooctanoic acid, isononanoic acid and the like.

(3) Aliphatic polyhydric alcohol and carbon number 3 to
A partial ester of 9 with a linear or branched fatty acid,
It is also possible to use linear or branched aliphatic dibasic acids or complex esters with aromatic dibasic acids.

Examples of such aliphatic polyhydric alcohols include trimethylolpropane, trimethylolethane,
Pentaerythritol, dipentaerythritol, etc. can be used.

The fatty acids having 3 to 12 carbon atoms include propionic acid, butyric acid, isobutyric acid, valeric acid, hexanoic acid, heptanoic acid, octanoic acid, nonanoic acid, decanoic acid, dodecanoic acid,
2-Methylhexanoic acid, 2-ethylhexanoic acid, isooctanoic acid, isononanoic acid, isodecanoic acid, 2,2'-dimethyloctanoic acid, 2-butyloctanoic acid and the like can be used.

In this complex ester, it is preferable to use a fatty acid having 5 to 7 carbon atoms, more preferably 5 to 6 carbon atoms, and the ester oil formed by this is used as a refrigerant particularly at low temperature. The compatibility of can be improved.

As such a fatty acid, valeric acid, hexanoic acid, isovaleric acid, 2-methylbutyric acid, 2-ethylbutyric acid or a mixture thereof is used, and those having 5 carbon atoms and 6 carbon atoms are used.
Fatty acids obtained by mixing these in a weight ratio of 10:90 to 90:10 can be preferably used.

As the aliphatic dibasic acid used for esterification with polyhydric alcohol together with this fatty acid, succinic acid, adipic acid, pimelic acid, suberic acid, azelaic acid, sebacic acid, undecanedioic acid, dodecane Diacid,
It is advisable to use tridecanedioic acid, carboxyoctadecanoic acid, carboxymethyloctadecanoic acid, docosanedioic acid, etc. Also, as aromatic dibasic acid, phthalic acid, isophthalic acid, and aromatic tribasic acid, trimellitic acid, aromatic Examples of the tetrabasic acid include pyromellitic acid.

The ratio of the fatty acid to the aliphatic dibasic acid or the aromatic dibasic acid, the aromatic tribasic acid or the aromatic tetrabasic acid may be 6: 1 (molar ratio). In this case, the ratio of the total amount of the fatty acid, the aliphatic dibasic acid or the aromatic dibasic acid, and the amount of the aliphatic polyhydric alcohol used may be 7: 1 (molar ratio).

In the esterification reaction, first, a polyhydric alcohol is reacted with an aliphatic dibasic acid or an aromatic dibasic acid at a predetermined ratio to partially esterify it, and then the partially esterified product is reacted with a fatty acid. The refrigerating machine lubricating oil of the present invention may be prepared, or the reaction order of the acids may be reversed, or the acids may be mixed and subjected to esterification.

(4) Further, linear or branched dialkyl esters of aliphatic dibasic acids (having 16 to 22 carbon atoms) may be used.

Examples of the aliphatic dibasic acid include succinic acid, glutaric acid, adipic acid, pimelic acid, suberic acid, azelaic acid, sebacic acid, undecanedioic acid, dodecanedioic acid, tridecanedioic acid, carboxyoctadecanoic acid and carboxymethyloctadecane. Acids, docosanedioic acid, and those having properties equivalent to these are included. Preferred aliphatic dibasic acids are succinic acid, adipic acid, sebacic acid, undecanedioic acid, dodecanedioic acid, carboxyoctadecanoic acid, carboxymethyloctadecanoic acid and the like.

The alcohol component is an alcohol having 5 to 8 carbon atoms, specifically amyl alcohol, hexyl alcohol, heptyl alcohol and octyl alcohol, and isomers thereof, preferably isoamyl alcohol and isohexyl alcohol. And octyl alcohol.

Specifically, dioctyl adipate, di-
Examples include isoheptyl adipate, dihexyl sebacate, diheptyl succinate and the like.

(5) Dialkyl esters of aromatic dibasic acids (having 18 to 26 carbon atoms) can also be used.

Examples of the aromatic dibasic acid include phthalic acid, isophthalic acid and the like, and the alcohol component in the dialkyl ester has 5 carbon atoms.
~ 8 alcohols, including amyl alcohol, hexyl alcohol, heptyl alcohol, octyl alcohol, and isomers thereof. Preferred alcohols include isoamyl alcohol, isoheptyl alcohol and octyl alcohol. Aromatic diesters include dioctyl phthalate, diisoheptyl phthalate, diisoamyl phthalate and the like.

(6) As the alcohol component, monohydric alcohols selected from methanol, ethanol, propanol, butanol, etc., and isomers thereof, trihydric alcohols such as glycerin, trimethylolpropane and ethylene oxide, propylene oxide, etc. 1 mol to 1 of alkylene oxide selected from butylene oxide, amylene oxide, etc., and isomers thereof.
0 mol, preferably 1 to 6 mol of adduct is used.

As the organic carboxylic acid ester, an alkylene oxide adduct of a monohydric alcohol is adipic acid,
Pimelic acid, suberic acid, azelaic acid, sebacic acid,
There are diesters obtained by esterification with an aliphatic dibasic acid such as undecanedioic acid, dodecanedioic acid, carboxyoctadecanoic acid, carboxymethyloctadecanoic acid and docosanedioic acid, or an aromatic dibasic acid such as phthalic acid.

Further, 1 to 10 of alkylene oxides of polyhydric alcohols such as glycerin and trimethylolpropane are used.
The molar adduct is converted to a linear or branched fatty acid having 3 to 12 carbon atoms, for example, propionic acid, butyric acid, valeric acid, hexanoic acid, heptanoic acid, octanoic acid, nonanoic acid, decanoic acid, dodecanoic acid, 2- Methylhexanoic acid, 2-ethylhexanoic acid, isooctanoic acid, isononanoic acid, isodecanoic acid,
Esters obtained by esterification with 2,2′-dimethyloctanoic acid, 2-butyloctanoic acid or the like can be used.

As the fatty acid constituting the above organic carboxylic acid ester, a linear or branched fatty acid can be used, but when a branched fatty acid is used, it is more excellent in hydrolysis stability and Compatibility with hermetic coils can be achieved.

These organic carboxylic acid esters can be obtained by esterifying alcohols and fatty acids in the presence of an acid catalyst, for example, phosphoric acid, but usually the total acid value is 0.1 to 0.5 mg. KOH / g, peroxide value 0.1-5 meq./Kg, aldehyde value 0.1-5 mg KOH /
g, bromine number 1-100mg / 100g, ash content 5-50pp
It is possible to obtain m having a water content of 300 to 1000 ppm.

However, when the total acid value of the refrigerating machine lubricating oil is high, problems such as corrosion of metal parts occur, and further the refrigerating machine lubricating oil itself is hydrolyzed to function as a refrigerating machine lubricating oil. In general, in refrigerators and the like, the motor part is arranged in the lubricating oil, so that high insulation is required, so that the lubricating oil for refrigerators has a total acid value of 0. It is recommended to use less than 05mg KOH / g.

Further, the peroxide value, the aldehyde value, and the bromine number index are kept low in order to further improve the refrigerant stability, and the ash content is restrained in order to suppress sludge and the like, and the hydrolysis stability is further improved. However, it is necessary to suppress the water content due to the insulating property.

Therefore, by refining the above-mentioned esters obtained by a normal esterification reaction and adjusting the indexes showing the above-mentioned various properties of the ester oil within a range suitable as a refrigerating machine oil, a more excellent refrigerating machine oil is obtained. be able to.

The organic carboxylic acid ester may be purified by contacting it with silica gel, activated alumina, activated carbon, zeolite or the like. The contact conditions at this time may be appropriately determined according to various situations, but the temperature is preferably 100 ° C. or lower.

Examples of the polyalkylene glycol include polyethylene glycol, polypropylene glycol, a copolymer of ethylene oxide and propylene oxide, and the like. The terminal group is a methyl group, an ethyl group,
It may be substituted with a propyl group or a butyl group. Average molecular weight is 500 to 1800, preferably 800 to 1600
If it is less than 500, the compatibility with the refrigerant at high temperature is high, but the viscosity is low, and the thermal stability is poor, which is not preferable. If it exceeds 1800, the viscosity is high but the phase with the refrigerant is high. It loses solubility.

A viscosity index improver may be added to the lubricating oil for refrigerator of the present invention for the purpose of obtaining desired viscosity and viscosity index required for various refrigerators.

Examples of such a viscosity index improver include polyolefin, polymethacrylate, polyisobutylene,
Polyalkylstyrene, ethylene-propylene copolymer, styrene-diene hydrogenated copolymer, styrene-maleic anhydride copolymer, etc. can be used.

The polyolefin has from 35 to 35 carbon atoms.
3,500, preferably obtained by the copolymerization of any one kind or two or more kinds selected from olefinic hydrocarbons with or without branching in the range of 50 to 700, and the average. Molecular weight 500 to 50,000
It is selected from 0, preferably 700 to 10,000 products, with preference given to the removal of unsaturated bonds by hydrogenation. Preferable polyolefins are, for example, polybutene, poly α-olefin and ethylene / α-olefin copolymer. Kinematic viscosity at 40 ° C is 10
It is possible to use the one of 10,000 to 10000 cSt.

As the polymethacrylate, an alkyl group having 1 to 18 carbon atoms is used as an ester component, and a homopolymer having a degree of polymerization of 5 or more such as polymethacrylate or polyacrylate, or methacrylic acid or acrylic acid is used as a copolymerization component. Is a copolymer. As the non-dispersed polymethacrylate, the alcohol component forming the ester is an alkyl group having 1 to 16 carbon atoms and an average molecular weight of 20,000 to 1
As a polymethacrylate of 500,000, the alcohol component forming the ester has 1 to 16 carbon atoms.
A copolymer of methacrylic acid, which is an alkyl group, and ethylene or propylene substituted with a polar group and having an average molecular weight of 20,000 to 1,500,000 can be used.

The viscosity index improver is used in an amount of 0.1 to 20% by weight, preferably 1 to 10% by weight, based on the base oil.

For refrigerators, the viscosity at 100 ° C. is 2 mm ² / s to 9 mm ² / s, preferably 3 mm ² / s to 7 mm ² / s.
7mm ² / s ~ for car air conditioners
It is recommended to use one with a size of 30 mm ² / s and 7 mm for a reciprocating type compressor even in a car air conditioner.
² / s ^{~15mm 2} / s, preferably ^{8mm 2 / s ~11mm 2 / s} ,
15mm ² / in rotary type compressor
s ~40mm ² / s, preferably an ester oil having a viscosity range of 20mm ² / s ~35mm ² / s is preferably used.

The refrigerator lubricating oil of the present invention has a viscosity range of 2
those ^{mm 2 / s ~100mm 2 / s} , preferably 2 mm ² / s to 8
It is 0 mm ² / s, but if it is less than 2 mm ² / s, the viscosity is too low even if the compatibility with the refrigerant at high temperature is high, the lubricity and sealing characteristics are poor, and it cannot be used. It is not preferable because it is also poor in properties, and if it exceeds 100 mm ² / s, it is not preferable because the compatibility with the refrigerant decreases.

Even within this range, the usable viscosity range varies depending on the model used as described above, and for a refrigerator, if it exceeds 9 mm ² / s, the friction loss in the sliding portion becomes large. There's a problem.

Further, in the reciprocating type car air conditioner, if it is less than 7 mm ² / s, there is a problem of lubricity and it is 15 mm.
^If it exceeds ² / s, there is a problem that the friction loss in the sliding portion is large, and if it is less than 15 mm ² / s in the rotary type air conditioner, there is a problem of sealing characteristics.

Various additives usually used can be used in the refrigerating machine oil of the present invention. As an antiwear agent,
Formula (RO) ₃ P = S (wherein R is an alkyl group, an allyl group, a phenyl group, may be the same or different.)
, Specifically, trialkylphosphorothionate, triphenylphosphorothionate, sulfur antiwear agents such as alkyldiallylphosphorothionate, diphenyl sulfide, diphenyl disulfide,
Sulfides such as di-n-butyl sulfide, di-n-butyl disulfide, di-tert-dodecyl disulfide, di-tert-dodecyl trisulfide, sulfurized oils such as sulfurized spalm oil, and sulfurized dipentene, xane Thiocarbonates such as tic disulfide, zinc primary alkylthiophosphates, zinc secondary alkylthiophosphates, zinc alkyl-allylthiophosphates, zinc thiophosphate antiwear agents such as zinc allylthiophosphates and the like can be used.

As the phosphorus-based antiwear agent, benzyl diphenyl phosphate, allyl diphenyl phosphate, triphenyl phosphate, tricresyl phosphate, ethyl diphenyl phosphate, tributyl phosphate, dibutyl phosphate, cresyl diphenyl phosphate. , Dicresyl phenyl phosphate, ethyl phenyl diphenyl phosphate,
Phosphoric acid such as diethylphenyl phenyl phosphate, propyl phenyl diphenyl phosphate, dipropyl phenyl phenyl phosphate, triethyl phenyl phosphate, tripropyl phenyl phosphate, butyl phenyl diphenyl phosphate, dibutyl phenyl phenyl phosphate, tributyl phenyl phosphate Esters, phosphites such as triisopropyl phosphite, diisopropyl phosphite, hexamethylphosphoric triamide, n-butyl-n-dioctylphosphinate, di-
Other phosphorus compounds such as n-butylhexylphosphonate, amine dibutylphosphonate, dibutylphosphoramidate can be used. The proportion of these antiwear agents used is 0.01 to 5% by weight, preferably 0.1 to 3% by weight, based on the base oil.

The above anti-wear agents may be used alone or in combination of two or more.

As the antioxidant, amine-based antioxidants such as dioctyldiphenylamine, phenyl-α-naphthylamine, alkyldiphenylamine and N-nitrosodiphenylamine, 2.6-di-t-butylparacresol, 4.4'- Methylenebis (2.6-di-t-butylphenol), 2.6-di-t-butyl-α-dimethylamine paracresol, phenolic antioxidants such as 2.6-di-t-butylphenol, Tris (2 .4-
Phosphorus-based antioxidants such as di-t-butylphenyl) phosphite, trisnonylphenyl phosphite, and triphenyl phosphite may be used, and the use ratio thereof is 0.01 to 10% by weight with respect to the base oil, preferably Is preferably 0.01 to 1.0% by weight.

As the corrosion inhibitor, isostearate, n-octadecyl ammonium stearate, duomine T.diolate, lead naphthenate, sorbitan oleate, pentaerythritol oleate, oleylsarcosine, alkylsuccinic acid, alkenylsuccinic acid. , And their derivatives, etc., and their use ratio is 0.001-1.0% by weight, preferably 0.01-0.
It is recommended to use 5% by weight.

Silicone may be used as the defoaming agent, and the proportion of the defoaming agent used is 0.0001 to 0.
003% by weight, preferably 0.0001 to 0.001% by weight may be used.

As the metal deactivator, for example, benzotriazole, benzotriazole derivative, thiadiazole, thiadiazole derivative, triazole, triazole derivative, dithiocarbamate, etc. may be used, and the use ratio thereof is 0 relative to the base oil. 0.01% by weight to 1
It is advisable to use 0% by weight, preferably 0.01% to 1.0% by weight.

Further, as a rust preventive, for example, succinic acid, succinic acid ester, oleic acid tallow amide, barium sulfonate, calcium sulfonate, etc. may be used.
The use ratio thereof is 0.01% by weight to 10% by weight, preferably 0.01% by weight to 1.0% by weight.

[0067]

[Operation and effect of the invention] At present, as a lubricating oil for refrigerators,
Although high-viscosity polyether synthetic oil has been developed, the operating temperature of refrigerating machine oil is usually -30 to 100 ° C, and the polyether synthetic oil is hydrogen-containing halogenated hydrocarbon, especially non-chlorine halogenated hydrocarbon. When mixed with hydrogen, the reason is not clear, but there are problems such as phase separation at high temperature, hygroscopicity, and lubricity.

It is important that the refrigerating machine oil has good compatibility with the refrigerant, and it is necessary that the refrigerating machine oil does not separate from the refrigerant and does not react at high or low temperatures. Poor compatibility with the refrigerant causes problems such as seizure of hardware in the high temperature part of the refrigerator.

In the refrigerator lubricating oil of the present invention, the fumaric acid ester polymer having a specific structure is a hydrogen-containing refrigerant, particularly 1.1.1.
It has been found that it has high compatibility with non-chlorine type refrigerants such as 2-tetrafluoroethane, is thermally and chemically stable, and has excellent lubricity.
In particular, it is excellent as a lubricating oil for refrigerators using non-halogenated halogenated hydrocarbons.

The refrigerating machine lubricating oils differ in their working viscosities depending on the models used, but in order to adjust the viscosity and viscosity index of the fumaric acid ester polymer, organic carboxylic acid esters, etc., which are usually used, are used. The refrigerating machine lubricating oil and the viscosity index improver such as polymethacrylate may be mixed and used, whereby a lubricating oil suitable for various refrigerating machines can be obtained.

The present invention will be described below with reference to examples. In the examples,% indicates% by weight, and viscosity indicates kinematic viscosity at 100 ° C.

[0072]

Example 1 In a 500 ml four-neck flask, 305 mmo of diethyl fumarate obtained by isomerizing diethyl malate was isomerized.
1 (52.5 g) and p-xylene 400 ml,
A thermometer, a dropping funnel, and a cooling pipe were attached and set in an oil bath. Stir with a magnetic stirrer under a nitrogen stream and keep the temperature at 135 ° C while refluxing.
IBN (2,2'-azobisisobutyronitrile) 35
A p-xylene solution of mmol (5.8 g) was added dropwise over 11 hours, and the mixture was further heated and refluxed for 19 hours. After this,
The solvent and unreacted materials were distilled off under reduced pressure, and the reaction product was 49 g.
(Yield 94%) was obtained.

[Table 1] below shows the viscosity of the reaction product and the evaluation of performance as a lubricating oil for refrigerators.

[0074]

Example 2 Using the same apparatus as in Example 1, diethyl fumarate was adjusted to 305 mmol and 250 ml of o-xylene,
A reaction product was obtained in the same manner as in Example 1 except that AIBN was 50 mmol, the reaction temperature was 135 ° C., and the reaction time was 4 hours. The viscosity and performance evaluation of the reaction product are shown in the following [Table 1].

[0075]

Example 3 The same apparatus as in Example 1 was used, except that diethyl fumarate was adjusted to 310 mmol, no solvent was used, and AIBN was used.
A reaction product was obtained in the same manner as in Example 1 except that 10 mmol, the reaction temperature was 80 ° C., and the reaction time was 8 hours. The viscosity and performance evaluation of the reaction product are shown in the following [Table 1].

[0076]

Example 4 The same apparatus as in Example 1 was used, except that diethyl fumarate was adjusted to 310 mmol, no solvent was used, and AIBN was used.
A reaction product was obtained in the same manner as in Example 1 except that 2 mmol, the reaction temperature was 80 ° C., and the reaction time was 8 hours. The viscosity and performance evaluation of the reaction product are shown in the following [Table 1].

[0077]

Example 5 The same apparatus as in Example 1 was used, except that diethyl fumarate was set to 305 mmol, no solvent was used, and AIBN was used.
A reaction product was obtained in the same manner as in Example 1 except that 35 mmol, the reaction temperature was 135 ° C., and the reaction time was 12 hours.
The viscosity and performance evaluation of the reaction product are shown in the following [Table 1].

[0078]

Example 6 Using the same apparatus as in Example 1, the amount of dibutyl fumarate was 217 mmol, the reaction temperature was 118 ° C., and the AI was AI.
A reaction product was obtained in the same manner as in Example 1 except that the MIBK solution containing 27.5 mmol of BN was added dropwise over 12 hours, and the reaction time was changed to 24 hours. The viscosity and performance evaluation of the reaction product are shown in the following [Table 1].

[0079]

Example 7 A mixed oil composed of 63% of the reaction product prepared in Example 4 and 37% of an organic carboxylic acid ester [trade name P-51 (manufactured by Mobile Oil Co.)] was used as a lubricating oil for a refrigerator. The viscosity and performance evaluation of the mixed oil are shown in the following [Table 1].

[0080]

Example 8 A mixed oil containing 49% of the reaction product prepared in Example 4 and 51% of the ester reaction product of dipentaerythritol and C ₆ acid was used as a lubricating oil for a refrigerator. The viscosity and performance evaluation of the mixed oil are shown in the following [Table 1].

[0081]

Example 9 A mixed oil composed of 83% of the reaction product prepared in Example 3 and 17% of an organic carboxylic acid ester [trade name P-51 (manufactured by Mobile Oil Co.)] was used as a lubricating oil for a refrigerator. The viscosity and performance evaluation of the mixed oil are shown in the following [Table 1].

[0082]

Example 10 The refrigerator lubricating oil prepared in Example 4 was vacuum distilled into the refrigerator lubricating oil prepared in Example 2,
Lubricating oil for refrigerators was obtained by containing 5% of solid content obtained by cutting components having a low degree of polymerization. The viscosity and performance evaluation of the mixed oil are shown in the following [Table 1].

[0083]

Example 11 The refrigerator lubricating oil prepared in Example 2 containing 5% of polymethylmethacrylate having a weight average molecular weight of 12000 was used as a refrigerator lubricating oil. The viscosity and performance evaluation of the mixed oil are shown in the following [Table 1].

[0084]

[Comparative Example 1] Organic carboxylic acid ester [trade name P-51
(Manufactured by Mobile Oil Co., Ltd.)] was used as a lubricating oil for refrigerators. The viscosity and performance evaluation are shown in the following [Table 1].

[0085]

Comparative Example 2 The ester reaction product of dipentaerythritol and C ₆ acid was used as a lubricating oil for a refrigerator. Below [Table 1]
Shows the viscosity and performance evaluation.

[0086]

Comparative Example 3 Polypropylene glycol dimethyl ether was used as a lubricating oil for refrigerators. The viscosity and performance evaluation are shown in the following [Table 1].

A method for evaluating the above-mentioned refrigerator lubricating oil will be described.

(Compatibility test method) Sample oil and a refrigerant (1.1.1.2-tetrafluoroethane) were sampled and mixed in a glass tube in a proportion of 15% by volume of the total sample oil to a total volume of 2 ml. Then, the glass tube is placed in a constant temperature bath having a cooling device, and the separation temperature of the sample oil and the refrigerant at low temperature is measured. The total amount of sample oil is 10% by volume of 2 ml in total.
Samples are mixed and mixed as described above, and a glass tube is placed in a constant temperature bath having a heating device, and the separation temperature of the sample oil and the refrigerant at high temperature is measured.

[0089]

[Table 1]

As can be seen from this table, the lubricating oil for refrigerator of the present invention has a high compatibility with the hydrogen-containing refrigerant, is thermally and chemically stable, and is excellent in lubricity.

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁵ Identification number Office reference number FI technical display location C10M 105: 32) C10N 20:02 30:00 A 8217-4H 40:30 (72) Inventor Asano Satoshi 1-3-1, Nishitsurugaoka, Oi-cho, Iruma-gun, Saitama Prefecture Tonen Co., Ltd. Research Institute (72) Inventor Tadashi Niwa 1-3-1, Nishitsurugaoka, Oi-cho, Iruma-gun, Saitama Prefecture Tonen Research Institute (72) ) Inventor Hiro Ueno 1-3-1, Nishitsurugaoka, Oi-cho, Iruma-gun, Saitama Prefecture Tonen Co., Ltd.

Claims (2)

[Claims] 1. A lubricating oil for a refrigerator using a hydrogen-containing halogenated hydrocarbon, which contains a fumaric acid ester polymer represented by the following general formula [Chemical formula 1]. Lubricant. [Chemical 1] (In the formula, R ₁ and R ₂ are a linear or branched alkyl group having 1 to 9 carbon atoms, an allyl group, or a terminal-substituted or unsubstituted polyalkylene oxide group, which may be the same or different, R ₃ is an alkylene group, a substituted alkylene group or an alkylene oxide group, m is 0 or more, n is an integer of 1 or more, and R ₃ is 50 mol% or less of the whole) 2. A lubricating oil for a refrigerator using a hydrogen-containing halogenated hydrocarbon, comprising a fumaric acid ester polymer represented by the following general formula [Chemical formula 2] and a viscosity range at 100 ° C. of 2 mm ² / A lubricating oil for a refrigerator, which comprises an organic carboxylic acid ester having a s of 30 mm ² / s or a polyalkylene glycol. [Chemical 2] (In the formula, R ₁ and R ₂ are a linear or branched alkyl group having 1 to 9 carbon atoms, an allyl group, or a terminal-substituted or unsubstituted polyalkylene oxide group, which may be the same or different, R ₃ is an alkylene group, a substituted alkylene group or an alkylene oxide group, m is 0 or more, n is an integer of 1 or more, and R ₃ is 50 mol% or less of the whole)