JPH08259975A - Refrigerator - Google Patents

Abstract

PURPOSE: To obtain a refrigerator which uses a refrigerator oil highly compatible with a refrigerant mainly comprising a fluorocarbon contg. no chlorine (e. g. HFC-134a). CONSTITUTION: This refrigerator is applied for a refrigeration cycle consisting of a compressor 40, a condenser 41, an expansion mechanism 42, and an evaporator 43, uses a refrigerant mainly comprising a fluorocarbon contg. no chlorine and having a critical temp. of 40 deg.C or higher, and uses a refrigerator oil of which the base oil is a fatty acid ester having a viscosity of 2-70cSt at 40 deg.C and 1-9cSt at 100 deg.C and at least two ester bonds (-OCO-) in the molecule. The refrigerator oil, highly compatible with the refrigerant, exhibits an excellent lubricity and enables a highly reliable refrigerating cycle to be realized.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a refrigerating cycle and a refrigerant compressor, and more particularly, to a refrigerating machine oil composition having a critical temperature of 40 ° C. or higher and not containing chlorine, such as Freon 134a. The present invention relates to a refrigeration cycle constituent material system such as an electric insulating material and a desiccant which are hardly deteriorated by a refrigerating machine oil composition.

[0002]

2. Description of the Related Art In recent years, due to environmental pollution, particularly ozone destruction and global warming, chlorine-based fluorocarbons (chloro fluorocarbons, abbreviated as CFC) have been regulated worldwide.

The freons subject to the regulation are freons 11, freons 12, freons 113, freons 114, freons 115, etc., all of which contain chlorine. For example, refrigerators, dehumidifiers, air conditioners (air conditioners), etc. are frozen. Freon 12 that has been exclusively used as a refrigerant in a refrigerating apparatus of equipment is also subject to regulation.

Therefore, a substitute refrigerant is required, and recently, hydrogenated fluorocarbon (HFC), which has a low reactivity with ozone and has a short decomposition period in the atmosphere, has been attracting attention as an alternative refrigerant, and Freon 134a is used. Is a typical refrigerant. That is, Freon 134a has an ozone depletion potential (ODP).
But Freon 12 (dichlorodifluoromethane CCl
₂ F ₂ ) is 0, the global warming potential (GWP) is 0.3 or less when CFC 12 is 1, nonflammable, and thermophysical properties such as temperature-pressure characteristics are similar to CFC 12. Therefore, it is said that there is an advantage that it can be put to practical use without drastically changing the structure of a refrigerating device such as a refrigerator, a dehumidifier, an air conditioner (air conditioner) and a refrigerant compressor that have conventionally used Freon 12. It has come.

However, Freon 134a (1.1.1-
Tetrafluoroethane CH ₂ FCF ₂ ) has a very unique property because it has a unique chemical structure, and is not suitable for refrigerating machine oils such as mineral oil and alkylbenzene oil that have been used in the conventional Freon 12 refrigeration system. However, the compatibility is poor and practically impossible. Furthermore, compatibility with sliding parts of the compression machine, friction and wear resistance, influence on electrical insulation, influence on desiccant, etc. is a problem, and new materials for compressors and refrigeration systems are required. The development of the system has been eagerly awaited.

Therefore, first, before touching on the problem of compatibility between the refrigerant and the refrigerating machine oil, a conventional refrigerant compressor and refrigerating apparatus using a CFC-based refrigerant will be described with reference to FIGS. 7 to 9.

FIG. 7 is a vertical cross-sectional view of a main part of a conventional hermetic rotary compressor, FIG. 8 is a cross-sectional view for explaining the pushing amount of the compressor part, and FIG. 9 is a general refrigeration cycle. It is a block diagram of.

In FIG. 7, reference numeral 1 denotes a case related to a closed container that also serves as an oil sump, and an electric motor section 22 and a compressor section 23 are housed in the case 1.

The electric motor 22 comprises a stator 19 and a rotor 20, and the rotor 20 is fitted with a rotary shaft 4A made of cast iron. The rotating shaft 4A has an eccentric portion 3, and a shaft hole 17 is formed in a hollow shape at one end side.

In the winding portion 19a of the stator 19, the core wire is covered with an ester imide film, an electrically insulating film of polyethylene tyrephthalate is mounted between the stator core portion and the winding portion, and the rotating shaft The surface of 4A is finished by grinding.

The compressor portion 23 is a cast iron roller 7 which is fitted into the cylinder 2 made of an iron-based fuel and the eccentric portion 3 of the rotary shaft 4A and rotates eccentrically along the inside of the cylinder 2. A high speed steel vane 10 that reciprocates in the groove 8 of the cylinder 2 while abutting against it and being pressed by the spring 9 at the other end, is provided on both sides of the cylinder as both the bearing of the rotary shaft 4A and the side wall of the cylinder 2. The main bearing 5 and the sub bearing 6 made of cast iron or an iron-based sintered body are used as main mechanical elements.

The auxiliary bearing 6 is provided with a discharge valve 27, a discharge cover 25 is attached so as to form a silencer 28, and the main bearing 5, the cylinder 2, and the auxiliary bearing 6 are connected by bolts 21. .

The rear surface 11 of the vane 10 and the cylinder 2
The pump chamber 1 is surrounded by the groove 8 and the main bearing 5 and the auxiliary bearing 6.
2 are configured.

The main bearing 5 has a suction piece 14 capable of sucking the naphthene-based or alkylbenzene-based refrigerating machine oil 13A, in which the refrigerant CFC gas stored in the bottom of the case 1 is dissolved, into the pump chamber 12, and the auxiliary bearing 6 includes a pump. Room 12
There is a discharge port 16 that can discharge the refrigerating machine oil 13A to the oil feed pipe 15. The oil feed pipe 15 has a shaft hole 17 of the rotary shaft 4A.
Refrigerating machine oil 13A can be supplied to the sliding parts in the important places from the shaft hole 17 through the branch hole 18.

The operation of the rotary compressor thus constructed will be described with reference to FIGS. When the compressor is operated and the cast iron rotary shaft 4A is rotated, the heat-treated cast iron roller 7 is rotated accordingly, and the high speed steel vane 10 is pushed by the spring 9 and the cast iron is brought into contact with the roller 7 at its tip. Alternatively, it reciprocates in the groove 8 of the cylinder 2 of the iron-based sintered body, compresses the refrigerant (CFC 12) flowing from the refrigerant suction port (not shown), and the refrigerant discharges through the refrigerant discharge port 24 to the discharge pipe 29. Discharged from the compressor. The winding portion 19a and the electric insulating film (not shown) of the stator 19 are immersed in refrigerating machine oil in which freon is dissolved or exposed to a spray environment by mist.

In the conventional combination of the refrigerating machine oil composed of mineral oil or alkylbenzene and the Freon 12, the Freon 12 is completely compatible with the refrigerating machine oil in all usage ranges, and therefore, the combination of the refrigerating machine oil and the refrigerant in the compressor, which will be described later. It was not necessary to pay attention to the two-layer separation phenomenon and various problems regarding the compatibility of the refrigerating machine oil with the so-called Freon 134a in which the refrigerating machine oil stays in the heat exchanger. However, in the case of a chlorine-free fluorohydrocarbon-based refrigerant having a unique property, for example, Freon 134a, there is no practical refrigerating machine oil that easily dissolves the refrigerant, so that the compatibility between the refrigerant and the refrigerating machine oil is high. The problem of is the biggest problem in practical use.

Generally, in order to improve the performance of the compressor, that is, the coefficient of performance (COP) indicating the energy efficiency, it is necessary to minimize the mechanical loss and maximize the volumetric efficiency of the compressor.

As the mechanical loss of the refrigerant compressor, the friction loss in the journal bearing and the thrust bearing in the mechanical section, the power of stirring oil, etc. account for most of the mechanical loss. Generally, it is based on the theory of fluid lubrication of the journal bearing. It has been said that minimizing the friction coefficient (μ) value in the formula shown below is the best way.

[0019]

[Equation 1]

Here, N: rotational speed P: surface pressure η: viscosity D: shaft diameter C: diameter clearance That is, in a refrigerant compressor operated under fluid lubrication conditions, in addition to structural factors of size and shape, operation is performed. This shows that the actual viscosity of the refrigerating machine oil in the dissolved state of CFC, which is a factor governed by the environment, is greatly related to the mechanical loss of the compressor.

On the other hand, the condition for keeping the volumetric efficiency at a maximum is to completely seal the components that perform the compression operation in the machine room for compressing the refrigerant gas so that the refrigerant gas does not leak from the high pressure side to the low pressure side. That is. Even in this case, it is necessary to pay attention to the fact that the actual viscosity of the refrigerating machine oil in which the refrigerant is dissolved plays an important role.

As described above, in the refrigerant compressor and the refrigerating apparatus using the same, which have been conventionally used in the Freon 12, the actual viscosity of the refrigerating machine oil at the rated operation point under the normal operating conditions is the optimum state. This means that it is important for the performance of the compressor.

On the other hand, refrigerating devices such as refrigerators, dehumidifiers, and air conditioners, although rare, are often operated in a high temperature environment far exceeding normal operating conditions. As it becomes thinner, it enters the so-called boundary lubrication region where metal contact occurs between the bearing sliding parts, the friction coefficient increases temporarily and heat is generated.
Biting and seizure adhesion phenomena occur between the bearing and the rotating shaft, which causes the reliability of the refrigerant compressor to be impaired. Therefore, it is necessary to devise so that a fatal problem does not occur even under the boundary lubrication condition. In a conventional refrigerant compressor using Freon 12, chlorine in Freon 12 effectively acts as an extreme pressure agent. That is, when a bite or seizure adhesion phenomenon occurs between the bearing and the rotary shaft, the refrigerant CFC 12 dissolved in the refrigerating machine oil as the bearing lubricating oil is decomposed by the friction heat,
The decomposition product chlorine reacts with the iron on the bearing surface to form iron chloride, which acts as a lubricant.

As described above, in a refrigerating apparatus, such as a refrigerator, that uses a high-pressure container type rotary compressor,
The operating conditions at an ambient temperature of 30 ° C are as follows: discharge pressure of the compressor is about 10 kg / cm ² abs, oil temperature is about 100 ° C, and actual viscosity of oil is 1 to 4.
Refrigerating machine oil of alkylbenzene or mineral oil that becomes cSt (56 cSt at 40 ° C, 6 cS at 100 ° C)
t) is good in terms of the coefficient of performance showing the energy efficiency and the reliability of the product, and most of the products have been used in this range.

On the other hand, a refrigeration system using a low-pressure container type reciprocating compressor (the structure and operation of which are omitted),
For example, in a refrigerator, operating conditions at an ambient temperature of 30 ° C. are as follows: compressor suction pressure of about 1.6 kg / cm ² abs, oil temperature of 85
C., mineral oil type refrigerating machine oil having an actual viscosity of 2 to 6 cSt of oil (at 40.degree. C., 8 to 15 cSt, at 100.degree. C.,
Those of 1.8 to 4.2 cSt) have been used as a refrigerant compressor and a refrigerating device.

Next, a basic refrigerating cycle in which the refrigerant compressor for sucking, compressing and discharging the fluorocarbon refrigerant is arranged will be described with reference to FIG.

As shown in FIG. 9, the compressor 40 has a low temperature,
The low-pressure refrigerant gas is compressed, and the high-temperature, high-pressure refrigerant gas is discharged and sent to the condenser 41. The refrigerant gas sent to the evaporator 41 becomes a high-temperature, high-pressure refrigerant liquid while releasing its heat into the air, and is sent to an expansion mechanism (for example, an expansion valve or a capillary tube) 42. The high-temperature, high-pressure refrigerant liquid passing through the expansion mechanism becomes low-temperature, low-pressure wet vapor due to the throttling effect and is sent to the evaporator 43. The refrigerant that has entered the evaporator 43 absorbs heat from the surroundings and evaporates, the low-temperature, low-pressure refrigerant gas that exits the evaporator 43 is sucked into the compressor 40, and the same cycle is repeated thereafter.

Conventionally, Freon 12 has been used as this refrigerant. However, since the use of Freon 12 has been regulated as described above, Freon 13 should be used as an alternative.
When using 4a, in the conventional mineral oil-based or alkylbenzene-based refrigerating machine oil for CFC 12, CFC 13 is used.
The compatibility with 4a was remarkably inferior, which caused many problems in practical use. Therefore, refrigerating machine oil having excellent compatibility with Freon 134a has been actively developed,
Various refrigeration oils have been proposed.

As typical examples thereof, compounds having an ether bond as exemplified below are known.

For example, in Japanese Patent Laid-Open No. 1-259093, "a refrigerant oil for a CFC compressor" can be represented by a general formula (10) of propylene glycol monoether.

[0031]

[Chemical formula 23]

(Where R in the formula is an alkyl group having 1 to 8 carbon atoms and n is an integer of 4 to 19) is used as a base oil, and in JP-A 1-259094, propylene is used. The end of the glycol can be etherified and represented by the general formula (11) of the Jether type compound.

[0033]

[Chemical formula 24]

(However, in the formula, R ₁ and R ₂ have 1 to 8 carbon atoms.
Based on a number of alkyls, n is an integer, average molecular weight 300-60
0) can be represented by the general formula (12) of a monoether type compound of propylene glycol and an ethylene glycol copolymer in JP-A 1-259095.

[0035]

[Chemical 25]

(Where R is an alkyl group having 1 to 14 carbon atoms, m and n are integers, and the ratio of m: n is 6: 4 to 1 :).
9 average molecular weight 300-2000) and the like are disclosed.

These polyalkylene glycols are different from conventional mineral oils and alkylbenzene oils by introducing an ether bond into the molecule to enhance the affinity for CFCs 134a and to greatly improve the compatibility, thereby compressing them. The two-phase separation phenomenon (refrigerant and refrigerating machine oil are not melted and separated) in the sliding part of the machine prevents the refrigerant lubrication and the retention phenomenon due to the oil adhered to the inner wall of the heat exchanger causes the oil return to the compressor. Improvements have been made, and it is said that problems relating to the reliability of the compressor and the refrigeration system, such as seizure and biting of the sliding parts of the compressor, will be solved.

However, those containing a large amount of ether bonds (C--O--C) in the molecule as above (1) have a high saturated moisture absorption rate (easily absorb water) (2) have a low volume resistivity ( 3) Poor oxidative stability and easy increase in total acid value. However, it is unsuitable for a refrigerant compressor and a refrigeration system using a hermetic motor as an electric motor.

That is, although the compatibility with the refrigerant is improved, there is a problem that it is superior to the insulating material of the motor and deteriorates the electrical insulation characteristics. In each of the above compounds, the terminal group of the molecule having an ether bond is end-capped with hydrogen, and this hydrogen further increases the hygroscopicity. Therefore, it has been proposed to esterify this hydrogen to obtain a refrigerating machine oil represented by the following formula (see Japanese Patent Application Laid-Open No. 2-132178).

[0040]

[Chemical formula 26]

(Where R is a hydrocarbon group, R ¹ is an alkylene group, R ² is an alkyl group, and n is an integer such that the viscosity of this compound is 10 to 300 (40 ° C.)) Similar to the above, the improvement in the compatibility with the refrigerant is due to a large number of ether bonds existing in the molecule, and therefore, there is a similar problem.

From the above problem (1), the compound having an ether bond easily takes in water, and the water itself is hydrolyzed by the water and becomes unstable.

Further, the water freezes up and clogs the capillaries of the refrigeration cycle, causing a pressure imbalance. Further, from (2), the volume resistivity becomes low, and the voltage insulation becomes poor. From (3), when the total acid value increases, the compound is hydrolyzed and becomes unstable.

[0044]

As described above, the CFC 134a, which is an alternative refrigerant of the CFC 12, has a unique molecular structure, and therefore, it is used as a refrigerating machine oil such as a mineral oil type and an alkylbenzene type that have been conventionally used. However, there is a fatal problem that the compatibility with the refrigerating machine oil, which is the basis of the refrigerant compressor and the refrigerating apparatus, is lacking.

Attempts have also been made to improve the compatibility, but along with this, new problems such as a decrease in electrical insulation, a problem of water content, and problems of instability such as hydrolysis and decomposition of a compound by an acid occur. Came. Hereinafter, each problem will be described in more detail.

If a refrigerating machine oil having a poor compatibility is forcibly used, the refrigerant compressor and the refrigerating apparatus cannot be put to practical use in terms of performance and reliability as described below.

Generally, when the solubility of the refrigerating machine oil in the refrigerant is low, the oil discharged from the compressor is separated in the heat exchanger, the oil component remains on the wall surface, and the amount of oil returning to the compressor decreases. As a result, the oil level of the compressor lowers, a so-called oil rising phenomenon occurs, and the oil supply level decreases.

Further, in a refrigeration system in which a large amount of refrigerant is enclosed, when the temperature of the compressor is exposed to a low temperature, the liquid refrigerant is unevenly distributed in the bottom of the compressor. Since the low-viscosity liquid refrigerant existing in the above will be supplied to the sliding surface of the rotating shaft, it will be difficult to secure a lubricating oil film, and this will cause damage to the compressor.

On the other hand, in the refrigerating apparatus, the separated refrigerating machine oil adheres to the inner wall of the low-temperature evaporator to form a heat insulating layer, which significantly impairs heat transfer performance. If the expansion mechanism (capillary tube) or the pipe piping works, the amount of refrigerant circulation is drastically reduced, and the cooling power is lowered. As a compressor, the pressure of suction gas decreases and the pressure of discharge gas increases, leading to thermal deterioration phenomenon of refrigerating machine oil and damage to mechanical bearings, significantly impairing long-term reliability as a refrigerant compressor and refrigeration system. It will be.

Therefore, an object of the present invention is to solve these problems of the prior art, and the first object thereof is refrigeration with high compatibility, which is suitable for a CFC-free refrigerant represented by CFC 134a and containing no chlorine. The purpose of the present invention is to provide a refrigerating device and a refrigerant compressor equipped with machine oil, and more specifically, to improve (1) water absorption, (2) systematic resistivity, (3) oxidative deterioration, etc. At the same time, it is based on the search for a new refrigerating machine oil composition that is compatible with Freon 134a under all operating conditions of the refrigerant compressor and refrigerating machine, and at least the critical dissolution for medium temperature refrigerating machines such as dehumidifiers. Develop a refrigerating machine oil that satisfies the first target that the temperature is 0 ° C. or lower, and a refrigerating machine oil that satisfies the second target that the critical melting temperature is −30 ° C. or lower for low temperature refrigerating devices such as refrigerators. thing More, in each object different refrigerating apparatus and a refrigerant compressor, performance, efficiency, and its object is to provide a reliable good refrigeration system.

Next, the refrigerant compressor and the refrigerating apparatus can increase the coefficient of performance (COP), which is the ratio of the refrigerating capacity of the refrigerant compressor to the input, under the normal operating conditions in which the refrigerant compressor is generally operated. From a long-term perspective, it will help prevent global warming (GWP).

As a means for improving the performance of the compressor, in order to reduce the input of the compressor, it is necessary to reduce the friction coefficient based on the fluid lubrication theory of the coaxial bearing. To this end, measuring the solubility of the Freon 134a and the refrigerating machine oil of the present invention and setting the optimum value of the actual viscosity of the oil used in the compressor minimizes the friction coefficient of the bearing, and the compressor and the refrigerating apparatus. It is to derive the highest coefficient of performance as.

Therefore, a second object is to define the optimum viscosity range of refrigerating machine oil for a refrigerating machine using a high pressure container type rotary compressor and a low pressure container type reciprocating compressor based on the above bearing theory. To improve performance,
The aim is high reliability. However, although the refrigeration system and the refrigerant compressor are, in reality, extremely rare, they may be subjected to a high-temperature environment exceeding the design expectation or ultra-severe operation such as overload operation. It is necessary to secure high reliability.

When the compressor using the Freon 134a is used in a so-called boundary lubrication region involving metal contact beyond the fluid lubrication region of the coaxial bearing, biting or seizure of the sliding portion of the compressor bearing may occur. However, there is a tendency that there are more than in the case of the conventional CFC 12. This is because when the bearing sliding part makes a metal contact, the flon 12 dissolved in oil decomposes to form a chemical film of iron chloride on the iron-based sliding friction surface. It works to prevent adhesion and seizure.

On the other hand, in the compressor using the Freon 134a, since it is a chlorine-free refrigerant and chlorine cannot be supplied, it is difficult to expect an extreme pressure action like the Freon 12 described above. is there.

Therefore, the third purpose is to use the Freon 134.
Even if the sliding bearing of the compressor runs out of oil using a CFC-free refrigerant represented by a, ultra-rigid operation is performed by using the refrigerating machine oil to which the extreme pressure agent is added. Even in the case of the above, it is an object of the present invention to provide a refrigerating device and a refrigerant compressor capable of preventing the sliding portion from being bitten or seized and ensuring sufficient reliability.

Further, a fourth object of the present invention is to provide a refrigerant compressor and a refrigerating apparatus which use a CFC-free refrigerant and a refrigerating machine oil composition, which are represented by CFC 134a, in an electric insulating film and an insulating material constituting an electric motor section. An object of the present invention is to provide a refrigeration apparatus and a refrigerant compressor provided with an electric insulation system in which an electric insulation material such as a coated winding can withstand long-term reliability.

Further, the Freon 134a is characterized by a high water absorption rate, and the refrigerating machine oil compatible with the Freon 134a is relatively hydrophilic even though it is considerably improved. Easy to bring in. Moisture in the refrigerating device is frozen in the evaporator on the low temperature side to block fine system pipes such as a capillary tube and reduce refrigerating performance. In the long term, refrigeration oil, refrigerant,
The electrically insulating material or the like causes a hydrolysis reaction, which causes negative characteristics such as generation of an acidic substance and reduction in mechanical strength. Therefore, a fifth object is to improve the reliability of the refrigerating apparatus by not absorbing the refrigerant but separately adsorbing the moisture in the refrigerating apparatus in which the CFC-free refrigerant containing chlorine such as the Freon 134a and the refrigerating machine oil coexist. Another object of the present invention is to provide a refrigerating apparatus equipped with a drier filled with a desiccant that works effectively.

[0059]

The first object of the present invention described above is (1). At least in a refrigeration cycle consisting of a compressor, a condenser, a drier, an expansion mechanism and an evaporator, a refrigerant having a critical temperature of 40 ° C. or higher and containing chlorine-free fluorocarbon-based refrigerant as a main component, and a viscosity. 2 to 7 when the temperature is 40 ° C
A refrigerating machine comprising a refrigerating machine oil having a base oil of ester oil of fatty acid having 0 cSt and 100 ° C. and 1 to 9 cSt and having at least two ester bonds (—O—CO—) in the molecule. Is achieved.

(2). As described above, as the ester oil, an ester of a fatty acid having two or more ester bonds in the molecule is essential, and one having one ester bond has poor compatibility with the refrigerant and cannot be used. Ester oil of fatty acids,
Obtained by ester reaction of alcohols and fatty acids, polyhydric alcohols are desirable as alcohols,
The fatty acid preferably has 6 to 8 carbon atoms and may be monobasic or polybasic. Also, ester oils include hindered ester oils and complex ester oils,
From the viewpoint of compatibility with the refrigerant, ester oil having a branched structure tends to be preferable to a linear structure. Examples of practical fatty acid ester oils are represented by the general formulas (1) to (5) below.

The general formulas (1) to (4) are examples of hindered ester oils, and the general formula (5) is an example of complex ester oils.

These ester oils may be used alone or in admixture of two or more, and at least 50 wt% of these ester oils may be contained, and the balance may be supplemented with other well-known refrigerating machine oil. General formula,

[0063]

Embedded image _{(R 1 · CH 2) 2} · C · (CH 2 COOR 2) 2 ... (1) ( Neo bench glycol carrying an ester linkage 2 months in the molecule (abbreviated as NPG) type of ester Example) General formula,

[0064]

[Image Omitted] R ₁ CH ₂ .C. (CH ₂ .COOR ₂ ) ₃ (2) (Example of trimethylolalkyl (propane, abbreviated as TMP) type ester having 3 ester bonds in the molecule) ) General formula,

[0065]

Embedded image C · (CH ₂ —CHOOR ₂ ) ₄ (3) (Example of pentaerythritol having 4 ester bonds in the molecule) (abbreviated as PET)) type ester) General formula,

[0066]

Embedded image _{(R 2 · OOCH 2 C)} 3 · C · CH 2 · O · CH 2 · C (CH 2 · COOR 2) 3 ... (4) ( di-carrying six of the ester bonds in the molecule Example of pentaerythritol (abbreviated as DPET) ester) General formula,

[0067]

[Chemical 31]

(Example of Complex Ester Having Four or More Ester Bonds in the Molecule) In each of the above general formulas, R ₁ is H or an alkyl group having 1 to 3 carbon atoms and R ₂ is 5 to 5 carbon atoms. With 12 alkyl groups, a plurality of species having different carbon numbers can be mixed. R ₃ represents an alkyl group having 1 to ₃ carbon atoms n represents 0 or an integer of 1 to 5, respectively.

With respect to the above general formulas (1) to (4), it is an ester of a polyhydric alcohol and a monocarboxylic acid. By arbitrarily selecting the type of alcohol and the combination of single or plural types of monocarboxylic acid, A desired viscosity grade can be obtained.

Further, regarding the complex type ester represented by the general formula (5), the chemical structure of the central dibasic acid (dicarboxylic acid) is changed to succinic acid (n = 2), glital acid (Glut abbreviation), adipine Acid (abbreviated as AZP), pimelic acid, suberic acid, azelaic acid, sebacic acid (n = 8)
To obtain high viscosity and a wide range of critical dissolution temperature range by changing the molecular weight of polyhydric alcohol and terminal monocarboxylic acid and changing the compounding ratio (molar fraction). You can

These hindered ester oils and complex ester oils are used alone or in combination to adjust the viscosity to obtain a base oil.

In the present invention, there are hydrofluorocarbons and fluorocarbons as the refrigerants having a critical temperature of 40 ° C. or higher and containing chlorine-free fluorocarbon refrigerant as a main component. Specific examples of the hydrofluorocarbon include difluoromethane (R32), bentafluorethane (R125), 1,1,2,2-tetrafluoroethane (R13).
4), 1,1,1,2-tetrafluoroethane (R134a), 1,1,2
-Trifluoroethane (R143), 1,1,1-trifluoroethane (R143a), 1,1-difluoroethane (R152a) and monofluoroethane (R161).

Specific examples of fluorocarbons include hexafluoropropane (C216) and octafluorocyclobutane (C318). Among these, especially 1,1,2,2
-Tetrafluoroethane (R134), 1,1,1,2-tetrafluoroethane (R134a), 1,1,2-trifluoroethane (R1
34), 1,1,1-trifluoroethane (R143a) and hexafluoropropane (C216) have boiling points close to those of conventional dichlorodifluoromethane (R12) and are preferable as alternative refrigerants.

In addition to using these hydrofluorocarbon or fluorocarbon type refrigerants alone, it is also possible to use them as a mixture of two or more kinds. By the way, the reason why the critical temperature of the refrigerant is set to 40 ° C. or higher is that a refrigeration apparatus having a condensation temperature of 40 ° C. or higher is required in the condenser.

The second object of the present invention is (3). A refrigerant compressor used in a refrigeration cycle, a motor consisting of a rotor and a stator in a closed container for storing refrigerating machine oil, a rotary shaft fitted to the rotor, and via the rotary shaft, A refrigerant compressor of a high-pressure container type, which accommodates a compressor unit connected to a motor, and in which a high-pressure refrigerant gas discharged from the compressor unit stays in a closed container. 2 to 7 when the viscosity is 40 ° C and a refrigerant containing a fluorocarbon-based refrigerant as a main component
Refrigerant compressor comprising 0 cSt and 1 to 9 cSt at 100 ° C., and a refrigerating machine oil having a base oil of ester oil of fatty acid having at least two ester bonds (—O—CO—) in the molecule. Is achieved by

At least 2 ester bonds are contained in the above molecule.
For the composition of the ester oil of the fatty acid possessed by the
As detailed in section (2).

In this type of high pressure container type rotary compressor, the actual oil viscosity due to the Freon 134a melting at a gas pressure of 9 to 11 kg / cm ² abs and an oil temperature of about 100 ° C. is 1.0 to 10.
Viscosity at 40 ° C is 2 to 7 so that it falls within 4.0 cSt.
The refrigerating machine oil described in the above item (2) of 0 cSt, preferably 5.0 to 32 cSt, is sealed in advance.

On the other hand, in the low pressure container type reciprocating compressor, (4). A refrigerant compressor used in a refrigeration cycle, a motor consisting of a rotor and a stator in a closed container for storing refrigerating machine oil, a rotary shaft fitted to the rotor, and via the rotary shaft, A refrigerant compressor of a low-pressure container type, which accommodates a compressor unit connected to a motor, and in which a high-pressure refrigerant gas discharged from the compressor unit is directly discharged to the outside of a closed container, at a critical temperature of 40 ° C. or higher, and A refrigerant containing chlorine-free fluorocarbon-based refrigerant as a main component, and a viscosity of 2 to 70 cSt at 40 ° C. and 1 to 9 cSt at 100 ° C.,
At least 2 ester bonds (-O-CO-) in the molecule.
And a refrigerating machine oil having a fatty acid ester oil as a base oil.

At least 2 ester bonds are contained in the above molecule.
For the composition of the ester oil of the fatty acid possessed by the
As detailed in section (2).

In the low pressure container type reciprocating compressor, the actual viscosity of the oil when the CFC 134a was melted at a suction gas pressure of 1.0 to 2.0 kg / cm ² abs and an oil temperature of 85 ° C. was 2.0 to 4.5 c.
When the viscosity is 40 ° C, it will be 5.0 to 1
5cSt, 2.0-4.5cSt above at 100 ° C
The refrigerating machine oil described in the item (2) is enclosed in advance.

The third object is achieved by adding an extreme pressure agent to the refrigerating machine oil described in (5) and (2) above.

The extreme pressure agent serves as an antiwear agent for the sliding portion, and is represented by, for example, an alkyl polyoxyalkylene phosphate represented by the general formulas (6) and (7), or a general formula (8). Examples thereof include dialkyl phosphate ester.

[0083]

Embedded image

[0084]

[Chemical 33]

However, R _{4 is} an alkyl group having 1 to 8 carbon atoms R _{5 is} H or an alkyl group having 1 to 3 carbon atoms Molecular weight: 400 to 700

[0086]

Embedded image

However, R _{6 is} an alkyl group having 8 to 16 carbon atoms, and these phosphoric acid esters may be added alone or in combination of two or more kinds. Further, the practical addition amount is 0.05 to 10 wt%.

Further, together with the above extreme pressure agent (antiwear agent),
It is also effective to add an acid scavenger, an antioxidant, an antifoaming agent and the like.

The acid scavenger is added in order to remove the ester oil when the acid component is present in the refrigerating machine oil, which causes the ester oil to decompose and become unstable, and reacts with an acid such as an epoxy compound. Compounds are preferred. Particularly preferred are diglycidyl ether compounds such as polyalkylene glycol diglycidyl ether, monoglycidyl ether compounds such as phenylglycidyl ether, and compounds having an epoxy group and an ether bond such as aliphatic cyclic epoxy compounds. The reason is that the epoxy group of these compounds captures the acid, and the ether bond contributes to the improvement of the compatibility between the refrigerating machine oil and the refrigerant to some extent.

The above-mentioned other additives are a chlorine scavenger for eliminating the influence of residues such as chlorine-based cleaning agents used when manufacturing compressors and refrigeration equipment, and oxidative deterioration during oil distribution and storage. Is an additive for preventing foaming, an additive for preventing foaming, etc., which is of a level that can be dealt with by conventional general techniques, and is not specifically restricted here.

In order to achieve the fourth object, Freon 1
In a refrigerating apparatus and a refrigerant compressor, in which a CFC-free refrigerator represented by 34a and a refrigerating machine oil containing the fatty acid ester oil according to the above item (2) as a base oil are used together, an electric insulation forming an electric motor section is provided. A crystalline plastic film having a glass transition temperature of 50 ° C. or higher, or a composite film obtained by coating a resin layer having a high gas transition temperature on a film having a low glass transition temperature is used as the film. It is desirable to use the above enamel-coated wire or an enamel wire in which a layer having a low glass transition temperature is used as a lower layer and a high layer is used as an upper layer.

And as a practical insulating film,
At least one insulating film selected from the group of polyethylene terephthalate, polybutylene terephthalate, polyphenylene sulfide, polyether ketone, polyethylene naphthalate, polyamide imide and polyimide is preferable, and the enamel coating is a group of polyester imide, polyamide and polyamide imide. At least one insulating layer selected from is preferable.

In order to achieve the fifth object, Freon 1
Fluorocarbon-free refrigerant represented by 34a and the above
In the refrigerating apparatus according to (1) above, which is used in combination with a refrigerating machine oil containing the fatty acid ester oil according to (2) as a base oil, the desiccant to be filled in the dryer has a pore size of 3.3 angstrom or less and 25 ° C. A carbon dioxide gas absorption container at a carbon dioxide gas partial pressure of 250 mmHg uses a synthetic zeolite composed of silicic acid and alkali metal aluminate complex salt of 1.0% or less.

[0094]

The hindered ester and complex ether having two or more ester bonds in the molecule and having a viscosity of 40 ° C. is 2 to 70 cSt, preferably 5 to 32.
cSt, 1 to 9 cSt at 100 ° C., preferably 2 to
The 6 cSt refrigerating machine oil of the present invention comprises at least a compressor, a condenser, an expansion mechanism, and an evaporator.
In a refrigeration system using a CFC-free refrigerant, which is represented by a, since the compatibility with the refrigerant is good in all temperature bands of each part used, there is a two-layer separated state of the refrigerant and the refrigerating machine oil. Will not do.

Therefore, (1) Separation of the two layers is eliminated at the oil storage portion in the compressor, and oil supply to the bearing sliding portion is guaranteed. (2) Freon gas with a low viscosity is always used in the low temperature environment of -30 ° C or less of the evaporator, in the state where the Freon gas discharged from the compressor is liquefied by the condenser.
Since it exists in a state of being dissolved in a and has a low viscosity state as a whole, the oil returns to the compressor well. Therefore, since the oil level lowering phenomenon of the compressor is eliminated, it is possible to secure the supply of oil to the bearing sliding portion, and it is possible to solve the problem of biting and seizure.

Further, this refrigerating machine oil has a small amount of saturated water, which is a drawback of the conventional polyoxyalkylene glycol oil, of less than 1/10, has a great effect of improving stability against oxidative deterioration, and has a level of electrical insulating oil. Certain volume low efficiency is 10 ¹³
It reaches Ωcm. Therefore, in the refrigerant compressor in which the motor unit is housed in the pressure vessel and the refrigerating apparatus using the same, the flon 134a and the refrigerating machine oil of the present invention are not separated, and both the performance and reliability of the compressor are excellent. The characteristics are shown. This refrigerating machine oil has excellent compatibility with conventional CFC-containing CFC refrigerants such as CFC 12 and CFC 22, and therefore CFC 134 may be used in some cases.
It is also possible to replace a part of a with these conventional CFC-containing CFC refrigerants and mix them for use.

Next, among the refrigerating machine oils of the present invention, 40
When the oil viscosity at 5 ° C is preferably 5 to 32 cts, it is sealed in a rotary compressor of a high-pressure container system, and the coefficient of performance of the compressor shows a peak at the point of using 15 cSt oil,
5 to 32 cSt is a coefficient of performance that indicates the performance of the compressor of approximately 1.4 or more, and when the combination of the conventional CFC 12 and alkylbenzene oil is 1, it is in the range of 0.95 to 0.93, and there is no practical problem. It is shown that. Also, 4
When the viscosity at 0 ° C is 56 cSt, the coefficient of performance of the compressor is higher than that of polyoxypropylene glycol oil.
It has been found that the refrigerator oil of the present invention is superior. This is because the ester bond possessed by the oil itself is mainly molecularly oriented to the surface of the iron-based sliding portion of the compressor shaft and bearing to improve lubricity, and due to the property of easily dissolving in the Freon 134a,
The actual viscosity decreases, and the actions of improving mechanical loss work together to improve the coefficient of performance of the compressor.

On the other hand, the low pressure container type reciprocating compressor is operated at a pressure in the container as small as 1 to ² kg / cm ² abs, so that the fluctuation range of the amount of dissolved flon and the actual viscosity is small. Therefore, the characteristics depending on the types of the refrigerant and the refrigerating machine oil are hard to appear, and the viscosity is 5 to 15 cSt at 40 ° C. and 2 at 100 ° C. as in the conventional case.
Those in the range of -4 cSt were found to be good in reliability and performance.

Next, in the refrigerating machine oil of the present invention, as an extreme pressure agent, for example, OH in the molecule of alkyl polyoxyalkylene phosphate ester and dialkyl phosphate ester.
When a suitable amount of primary and secondary strong phosphoric acid ester that retains the base is blended in an amount of 0.05 to 10 wt%, molecules are oriented on the surface of the iron-based sliding portion that constitutes the shaft and bearing of the compressor. The ester-bonded lubricating oil film can be removed to form a stronger phosphoric acid ester chemisorption film, which can improve the lubricity of the sliding parts and prevent chewing and seizure. .

When the lubricity of the refrigerating machine oil of the present invention to which the extreme pressure agent was added was tested and examined, the limit seizure surface pressure was found in the Falex test (oil seizure test) assuming that CFC 134a was not dissolved. Fluorocarbon 13 has been achieved assuming a high concentration dissolution.
Regarding the wear amount of the iron-based sliding member of the refrigerating machine oil in which 50% of 4a is dissolved, the wear amount is 1/5 of that of the additive-free product.
It was possible to reduce to the following. The proper range of the addition amount is 0.05 to 10 wt% as described above. In addition,
The results of this wear amount test are shown in FIG. 6, which will be described in detail in the section of Examples later, and the effect of reducing the wear amount by addition is remarkable.

Further, additives such as an acid scavenger, an antioxidant and a foaming agent which are usually used together with the above extreme pressure agent can be blended, and they act more effectively.

Next, regarding the electrically insulating material of the refrigerant compressor in which the Freon 134a and the refrigerating machine oil of the present invention are used in combination, the insulating film which is the electrically insulating system material of the motor part is a crystal having a glass transition temperature of 50 ° C. or higher. Plastics film, for example, polyethylene terephthalate, polybutylene terephthalate, polyphenylene sulfide, polyether ethyl ketone, polyethylene naphthalate, polyamide imide, polyimide, or a film having a low glass transition temperature, a resin layer having a high gas transition temperature is formed. The composite film to be coated is less likely to cause a deterioration phenomenon in tensile strength characteristics and electric insulation characteristics, and is within a range in which there is no practical problem. This is because the amount of water carried in and the amount of acid produced are much smaller than those of conventional polyoxyalkylene glycol oils, and therefore the deterioration phenomenon due to hydrolysis of the film itself is less likely to occur.

Similarly, for the magnet wire used in the motor part, the enamel coating having a glass transition temperature of 120 ° C. or higher, for example, a single layer of polyester imide, polyamide, polyamide imide or the like, or one having a low gas transition temperature as the lower layer, As with the above-mentioned film, the enamel coating having a composite having a high glass transition temperature as the upper layer has a deterioration in the coating due to hydrolysis, generation of cracks, softening, swelling, a decrease in dielectric breakdown voltage, etc., and is practically reliable. It turned out to be useful for improvement. It should be noted that some enamel coatings of magnet wires have self-lubricating properties, and internal lubricants and external lubricants are added for the purpose of improving electrical workability, but basically, the enamel coating itself The property inherits the above-mentioned basic structure as it is.

Finally, regarding the desiccant to be filled in the dryer of the refrigerating apparatus in which the Freon 134a and the refrigerating machine oil of the present invention coexist, in the present invention, the pore diameter is 3.3 angstroms or less, 25 ° C., carbon dioxide gas content. A synthetic zeolite composed of silicic acid and an alkali metal aluminate complex having a carbon dioxide gas absorption capacity at a pressure of 250 mmHg of 1.0% or less is preferable. Examples of this type include Union Showa Co., Ltd.
Product names XH-9, XH-600 and the like can be mentioned, and all have a small amount of adsorbed fluorine ions. When the carbon dioxide gas absorption capacity is 1.5% or more, the fluorine ion absorption amount is 0.24% or more, and the adsorption characteristics and fracture strength as the molecular sieves are deteriorated. Also,
The corroded crystallized deposits can cause clogging of the refrigeration cycle piping and damage to the bearing sliding parts of the compressor. From this point of view, the one in which the pore size of the present invention is regulated by the carbon dioxide gas absorber described above does not have such a concern, and it becomes possible to configure a highly reliable refrigeration system.

[0105]

Embodiments of the present invention will be described below with reference to FIGS. 1 to 6 and Tables 1 to 4. <Embodiments 1 to 17> This embodiment shows one embodiment for achieving the first object. In the hermetic rotary compressor related to the refrigeration cycle and the refrigerant compressor, the Freon 134a is used as the refrigerant. The refrigerating machine oil used has a viscosity of 2 to 70 cSt at 40 ° C., more preferably 5 to 32 cS.
An example in which an ester oil shown in Table 1 having two or more ester groups in the molecule, which has a viscosity of 1 to 9 cSt at 100 ° C., and more preferably 2 to 6 cSt, is used in combination is analyzed. For comparison, Table 1 also shows conventional refrigerating machine oils.

FIG. 1 shows a two-phase separation temperature diagram for explaining the compatibility of the Freon 134a and the refrigerating machine oil. The Freon 134a and the refrigerating machine oil are sealed in a high-pressure glass container, and the melting ratio and each temperature are kept. This is a summary of the results of visual observation of the state of the two-layer separation for each. The horizontal axis represents the concentration of oil in the Freon 134a, and the vertical axis represents the two-layer separation temperature. The first target value shown in this figure is the lower critical melting temperature required for a refrigerating machine having a medium temperature evaporator temperature (0 ° C. or less) such as a dehumidifier, and the second target value is It shows the lower critical melting temperature (each is a specification value) required by a refrigerating apparatus having a low temperature evaporator temperature (−30 ° C. or lower) such as a refrigerator.

Conventional refrigerating machine oil, for example, Nippon San Oil Co., Ltd.
Product name made by Suniso 4GSD (naphthenic) and Z300
(Alkylbenzene type) does not dissolve, and in the product name PAG56 (polyalkylene glycol) also manufactured by Nippon San Oil Co., Ltd., the lower critical solution temperature (indicated by L1) is -6.
It is indicated that 0 ° C. and the upper critical dissolution temperature (indicated by U1) are 35 ° C. The ester oil having two or more ester groups in the molecule of the present invention has a lower critical solution temperature (indicated by L2).
Indicates that the critical melting temperature is excellent at -70 ° C and the upper critical melting temperature (U2) is 70 ° C or higher. Of these, in the heat exchanger of the refrigeration system, the lower critical melting temperature is an important factor for practical use in the refrigerant compressor.

That is, FIGS. 9 and 10 show a refrigerating cycle configuration diagram of the refrigerating apparatus. The refrigerant compressor 40, the condenser 41, the drier 45, the expander 42, and the evaporator 4 are shown.
In the refrigerating apparatus consisting of 3
When operated in combination with 34a, the naphthenic mineral oils Suniso 4GSD and alkylbenzene oils Z300A (also a trade name of Nippon San Oil Co., Ltd.) shown in Conventional Examples 1 and 2 are
When a large amount of refrigerant is present and lie in the compressor, the refrigerant layer with high density is unevenly distributed in the lower layer and the refrigerator oil layer with low density is unevenly distributed in the upper layer due to the two-phase separation. As shown in the longitudinal cross-sectional view of the main part of (an example of the hermetic rotary compressor), the oil is supplied to the shaft 4A, the main bearing 5 and the sub bearing 6 through the suction port 14 of the pump by sucking the refrigerant layer unevenly distributed in the lower layer. Will be done. Therefore, the viscosity of the refrigerant layer is smaller than that of the refrigerating machine oil, and when oil is supplied to the bearing portion, the thickness of the oil film is small and metal contact easily occurs.
Further, since the temperature of the sliding friction surface instantly rises, the refrigerant gasifies and shifts to more severe conditions. If this phenomenon is repeated, the shaft and the bearing will be bitten or damaged due to seizure, and the performance of the refrigerant compressor will be lost.

When used in the heat exchanger of the refrigerating apparatus shown in FIGS. 9 and 10, for example, the evaporator 43 used at 0 to -60 ° C., the refrigerating machine oil discharged from the compressor 40 together with the refrigerant gas is Two layers are separated in the evaporator 41, and the refrigerating machine oil adheres to the inner wall of the heat exchanger pipe, which causes a retention phenomenon of the refrigerating machine oil and a heat insulating phenomenon of the heat exchanger. Impairs performance significantly and is not practical. In this respect,
The polyalkylene glycol shown in Table 1 in Conventional Example 3 is
Since the lower critical melting temperature is −60 ° C., it is advantageous that the two-layer separation does not occur in the evaporator 41, but the compressor 40 during operation is
Since the temperature of at least 80 ° C. is at least 80 ° C., when the upper critical dissolution temperature is 35, two-layer separation occurs completely.
When oil is supplied to the bearing portion in the same manner as in Nos. 2 and 2, the shaft and the bearing portion are damaged by biting and seizure, and the performance as the refrigerant compressor is lost.

Further, in the refrigerant compressor having the hermetic motor, for example, the rotary compressor shown in FIG.
Naturally, the property as an electric insulating oil is required.

FIG. 2 shows the relationship between the water absorption amount and the volume resistivity of the ester oil of the present invention, conventional mineral oil and polyalkylene glycol. Even when the water content is controlled to 500 ppm or less, the conventional polyalkylene glycol has a molecular weight of 10 due to the action of an ether bond in the molecule.
^It shows a low value of ¹² Ωcm or less, which is not desirable.

On the other hand, the ester group-introduced product of the present invention exhibits a high insulation performance of 10 ¹³ Ωcm or more.
It was found that it can be sufficiently put into practical use because it satisfies the standard value of "ISC2320" electric insulating oil. In addition,
The conventional mineral oil has high insulation performance,
Since it has poor compatibility with 4a, it cannot be put to practical use.

Next, the relationship between the type of ester oil suitable for CFC 134a, the chemical structure, and the lower critical solution temperature will be described in detail with reference to Table 1.

The type of ester oil having two or more ester groups in the molecule shown in the present invention means a monobasic organic acid or an ester of a polybasic organic acid and a polyhydric alcohol, and is a typical one. Neobenthyl glycol ester, trimethylolpropane (or ethane) as ester oil
-Based esters, hindered ester oils represented by pentaerythritol-based esters, complex-based esters, and the like, and the relations between the names of typical chemical compounds, viscosity, and critical solution temperature are shown.

[0115]

[Table 1]

Some of the sample names in Table 1 are the names of chemically synthesized ester oils. For example, in the case of NGP / n-C ₈ of Example 1, NGP is neopentyl glycol. approximately, n-C ₈ stands for the number eight normal organic acid carbon (linear fatty acids), an ester of neopentyl glycol and number eight normal organic acid carbon (linear fatty acids). In addition, the NGP / i-2EH of Example 3
If so, i-2EH is an abbreviation for iso-2ethylhexyl acid, and neopentyl glycol and iso-2ethylhexyl acid are used.
It represents an ester with hexylic acid (a fatty acid having a branched chain).

As a result, (1) neopentyl glycol esters (NPG) were prepared from the ester of dihydric alcohol neopentyl glycol and monocarboxylic acid monobasic acid as shown in Examples 1 to 4. It is characterized by having two ester groups in the molecule. These chemical structures show an important relationship with the compatibility with Freon 134a and the viscosity characteristics of oil.

That is, the monocarboxylic acid has 7 to 7 carbon atoms.
Ester in the range of 8 is good, and the lower critical solution temperature is -29.
~ -70 ° C, viscosity at 40 ° C is 2.8-7.0 cSt.
Met.

The lower critical solution temperature is lower as the carbon number of the monocarboxylic acid (fatty acid) is smaller, and the iso-2 ethylhexyl (i-2E) of Example 3 having a branched chain in the molecule.
H) acid and the iso-heptane (IC ₇ ) acid of Example 4 were found to be lower and more convenient. Further, Example 5 is an example in which the carbon number (11) of the carboxylic acid is increased in order to increase the viscosity, and the viscosity at 40 ° C. is 14.
It was found that the lower critical solution temperature was 9 cSt and the critical temperature was -40 ° C.

(2) Next, trimethylpropanol (TMP) ester having three ester bonds in the molecule will be described in Examples 6 to 10.

The ester oil obtained by the condensation of trimethylolpropane (TMP) which is a trihydric alcohol and monocarboxylic acid which is a monobasic organic acid has three ester groups in the molecule and has a carbon number of monocarboxylic acid. The viscosity at 40 ° C. is in the range of 10.8 to 32.2 cSt and the lower critical dissolution temperature is in the range of −20 to −60 ° C. for 6 to 8 pieces. Those having a temperature of −20 ° C. or lower include heptanoic acid (n-C ₇ ) of Example 6, octanoic acid (n-C ₈ ) of Example ₈ , iso-2ethylhexenoic acid (i-2EH) of Example 9, -60 ℃ or less,
Hexane (n-C ₆₎ acid of Example 7, an ester oil Isoheputan acid Example 10 (i-C _7). Here again, the lower critical dissolution temperature is characterized in that the smaller the carbon number is, the lower the carbon number is, and the lower the one containing a branched chain (iso), the lower the carbon number.

(3) As shown in Examples 11 to 13, ester oils obtained by condensation of tetrahydric alcohol pentaerythritol (PET) and monocarboxylic acid have four ester groups in the molecule, and monocarboxylic acid 6 carbon number
The viscosity at 40 ° C is 17.5 to 52.0 cSt for 8 pieces.
With higher viscosity, the lower critical melting temperature is -8 to -44 ° C.
The above range is shown, and the temperature shifts to the high temperature side with respect to the ester oil of the above-mentioned dihydric alcohol and trihydric alcohol. Among them, those having a lower critical dissolution temperature of −40 ° C. or lower are ester oils of hexane (n-C ₆ ) acid of Example 11 and iso-heptane (i-C ₇ ) acid of Example 13. . Here again, the lower critical dissolution temperature is characterized by a lower carbon number and a lower branched chain temperature.

(4) Next, as a method of containing four ester groups in the molecule, a dicarboxylic acid, which is a representative dibasic organic acid, is mainly used to condense a polyhydric alcohol and a monocarboxylic acid to form an ester. When it is attempted to increase the viscosity, the lower critical solution temperature is lowered and the viscosity can be easily increased. The thus designed molecule is a complex ester, which will be described in Examples 14 to 17 of the present invention.

Example 14 is dicarboxylic acid glutaric acid (abbreviated as Glut), dihydric alcohol neopentyl glycol (NPG), and monocarboxylic acid hexane (C ₆ ).
It is a complex ester of acid and has a viscosity of 3 at 40 ° C.
2.6 cSt, 100 ° C. was 5.9 cSt, and the critical dissolution temperature was −75 ° C. or lower.

Example 15 shows an example in which an intermediate viscosity grade was prepared by mixing Example 4 and Example 16. It was found that the lower critical solution temperature did not change significantly in this case as well.

In Example 16, dicarboxylic acid adipic acid (abbreviated as AZP), dihydric alcohol neopentyl glycol (NPG), and monocarboxylic acid decanoic acid (n-) were used.
C ₁₀ ) complex ester, Example 17 shows a complex ester of dicarboxylic acid glutaric acid (Glut), dihydric alcohol neopentyl glycol (NPG), monocarboxylic acid isohexanoic acid (i-C ₆ ). , 40 ° C viscosity 54.5-56.6 cSt, 100 ° C
Viscosity of 7.3 ~ 8.6cSt, lower critical solution temperature -60 ℃
I found that it was excellent.

In the complex ester, the carbon number C _{2 to} C ₁₀ of the dicarboxylic acid of the dibasic organic acid and the carbon number C _{5 to} C ₁₀ of the monocarboxylic acid of the monobasic acid are arbitrarily set, and further compounded. It is shown that by selecting the molar ratio to be selected and condensing with a polyhydric alcohol, it is possible to synthesize one having an arbitrary viscosity.

When these examples are arranged, the esters can be represented by the general formula as follows. Neopentyl glycol ester:

[0129]

Embedded image _{(R 1 · CH 2) 2} · C · (CH 2 COOR 2) 2 ... (1) trimethylolpropane (or ethane) based esters:

[0130]

Embedded image R ₁ CH ₂ C C (CH ₂ COOR ₂ ) ₃ (2) Pentaerythritol ester:

[0131]

Embedded image C. (CH ₂ —CHOOR ₂ ) ₄ (3) Complex ester:

[0132]

[Chemical 38]

More easily obtained, dipentaerythritol ester:

[0134]

Embedded image _{(R 2 · OOCH 2 C)} 3 · C · CH 2 · O · CH 2 · C (CH 2 · COOR 2) 3 ... (4) where, R _1: H or a 1 to 3 carbon atoms alkyl group R _2: an alkyl group having 5 to 12 carbon atoms, R ₃ may be mixed a plurality of types having different numbers of carbon atoms: alkyl groups having 1 to 3 carbon atoms n: 0 or be represented by an integer from 1 to 5 When designing an arbitrary viscosity, it was possible by selecting the type of polyhydric alcohol and carboxylic acid which is a basic organic acid.

In order to obtain an intermediate viscosity, it was possible to easily adjust the viscosity by blending a low viscosity oil and a high viscosity oil.

As described above, in a refrigerating apparatus using a CFC-free refrigerant containing no chlorine, such as CFC134a, the first of the hindered ester and complex ester having two or more ester bonds in the molecule is selected.
2 to 70 cS when the viscosity is 40 ° C. in the oil having a lower critical melting temperature of 0 ° C. or less, which is a target value of, or an oil having a lower critical melting temperature of −30 ° C. or less, which is a second target value.
t, more preferably 5 to 32 cSt, 1 at 100 ° C.
By selecting a material having a viscosity of 9 to 9 cSt, and more preferably 2 to 6 cSt, it is possible to obtain a compressor and a refrigerating machine which basically satisfy the performance and reliability.

These ester-based refrigerating machine oils are fluorocarbons 13
It has been confirmed that not only 4a but also Freon 152a (difluoroethane CH ₃ CHF ₂ ) and other chlorine-free Freon-based refrigerant gases have good compatibility, and are effective for high performance and high reliability of refrigeration equipment. there were.

Further, these ester oils of the present invention are well soluble in the conventional CFC-containing refrigerants such as Freon 12 and Freon 22 (chlorinated fluorohydrocarbon refrigerants), so a part of them is used as a mixture. In some cases, it was confirmed to be effective.

However, since these conventional CFC-containing refrigerants containing chlorine are subject to use restrictions due to environmental damage, it is desirable to set the content to 50% or less, and the ester oil of the present invention to at least 50%.

Next, an embodiment of the refrigerating apparatus for achieving the second object of the present invention will be illustrated.

<Embodiment 18> The rotary compressor shown in FIG. 7, which is a refrigerant compressor, is incorporated into the refrigerating apparatus shown in FIGS. 9 and 10, and the compressor temperature of 100 ° C., which is the reliability test condition of the refrigerator, is satisfied. , Discharge gas temperature 9.5 ℃ -10kgf / cm ² G
The coefficient of performance (COP), which is the ratio of the viscosity of the refrigerating machine oil stored in the compressor to the refrigerating capacity of the compressor and the input, was measured using the representative viscosity grade ester oils shown in Table 1. The results are shown in FIG.

In FIG. 3, the horizontal axis represents the actual viscosity of the refrigerating machine oil stored in the rotary compressor, the vertical axis represents the coefficient of performance of the compressor (displayed as a relative value), and the ester oil of the present invention is at 40 ° C. It shows the relationship between the actual viscosity of the refrigerator oil and the coefficient of performance (COP) for an alkylbenzene oil (Snisso Z-300A) having a viscosity of 5 to 56 cSt and using the conventional polyalkylene glycol and Freon 12. is there.

According to this, the conventional CFC 12 and 40 ° C.
When the relative coefficient of performance of Z-300A (alkylbenzene oil) having a viscosity of 56 cSt is 1.0,
The combination of polyalkylene glycol (PAG56) and Freon 134a in Conventional Example 3 was as low as 0.859, indicating that the energy efficiency was reduced by about 14%.

On the other hand, in Example 17 of the present invention, 40 ° C.
The complex ester oil having a viscosity of 56.6 cSt at that time was as good as 0.906. This is because the viscosity of the refrigerating machine oil when the CFC 134a is dissolved under the same operating conditions is as low as 4.35 cSt, so the journal bearing theory represented by the equation (9) representing the friction coefficient described in the section of the prior art is used. It is thought that the effect of reducing the friction loss based on the above, the power of stirring oil and the heat dissipation effect also move.

Next, when the ester oil of the present invention is an oil having a viscosity in the lower range of 5 to 32 cSt (40 ° C.) and the coefficient of performance is compared under the same conditions, 32.6 cS of Example 14 is obtained.
t (40 ° C.) is 0.926, 14.9 of Example 5.
0.966 for cSt (40 ° C.), 1 of Example 10
The value of 4.9 cSt (40 ° C.) was gradually improved to 0.973, and was conversely 0.95 at 5.5 cSt (40 ° C.) of Example 4.
3 showed a slight decrease.

From these results, the ideal ester oil suitable for the rotary compressor is 5 to 32 including the range around the viscosity of 14.9 cSt at 40 ° C. which is the best value.
(Precisely 5.5 to 32.6) cSt ester oil, which contains two or more ester bonds in the molecule as described above.

<Example 19> Next, a low pressure container type reciprocating compressor was used in combination with Freon 134a and the refrigerating machine oil illustrated in Table 1 of the present invention, and was incorporated in a refrigerator as a refrigerating apparatus to obtain high temperature reliability. A test (case pressure 1.6 kg / cm ² abs, case temperature 85 ° C., 100 V, 50 Hz) was performed.

FIG. 4 shows the results, in which the measured value of the viscosity of the refrigerating machine oil stored in the compressor is plotted on the horizontal axis, and the coefficient of performance (COP) indicating the performance of the compressor is plotted on the vertical axis. The viscosity of the refrigerating machine oil at 40 ° C. is shown in the examples of Table 1.
The characteristics of the relationship between the actual viscosity and the coefficient of performance in the actual operation of the sample refrigerating machine oils of 5, 14.9, 22.0, 32.6 and 56.6 cSt were plotted and connected by a substantially straight line.

From these results, it is shown that the low-pressure container type reciprocating compressor has a better coefficient of performance as the refrigerating machine oil having a lower viscosity shows that the actual viscosity is 2 to 4.2 cSt and the viscosity of the refrigerating machine oil at 40 ° C. 5.5-14.9 cSt
Can be said to be superior. The actual viscosity is 2 cSt
If it is smaller than the above, the surface roughness of the sliding parts of the compressor becomes
In conventional cast iron and iron-based sintered materials, there is a limit in finishing accuracy, and it enters the boundary lubrication region involving metal contact, the coefficient of performance decreases, and the bearing reliability tends to be poor.

<Embodiment 20> Next, the lubricity of a refrigerator and a refrigerant compressor for achieving the third object of the present invention will be described with reference to the following embodiment.

As a method for evaluating the lubricity, the seizure load in the Falex test in the atmosphere and the Freon 134a were set to 5.
A high-pressure atmosphere friction test for obtaining a seizure load in 0% dissolved refrigerating machine oil was carried out, and the correlation diagram of each result is shown in FIG. The seizure load is the load when the seizure occurs when a load is applied to the rotating sample pin from both sides, and is expressed in pounds (lb).

Here, the refrigerating machine oil used in the refrigerator of the present invention is typified by the ester oil of trimethylolpropane (TMP) and iso-heptane (i-C ₇ ) acid of Example 10 shown in Table 1, The relationship between the type and amount of the extreme pressure agent added to the ester oil and the lubricating characteristics was determined.
In addition, the material of the test piece used for the lubricity evaluation is the SNC-21 (nickel / chromium steel) of JIS standard for the pin and the SU of JIS standard for the block in the Falex test.
M41 (sulfur free-cutting steel) is the standard one, and the high-pressure atmospheric friction test, on the other hand, is the shaft material (eutectic graphite cast iron) and roller material (eutectic graphite cast iron) that have a proven record in rotary compressors. It is evaluated by a friction test of cylinders of the same material) and expressed by the load when the seizure phenomenon occurs.

As shown in the sample No. 1 in FIG. 5, the ester oil (oil of Example 10) containing no extreme pressure agent was subjected to a Falex baking load of 700 (lb) and a Freon 134a atmosphere of 9%.
While it showed a low value of 0 kgf / cm ² , Sample No. 2 was composed of a dialkyl phosphate which is one of the acidic phosphates having an active OH group in the molecule as an extreme pressure agent. 1% of the product name Chicrex H-10 manufactured by Sakai Chemical
In addition, by adding 1% of the ester compound of alkylene glycol and phosphoric acid (butyl polyoxypropylene phosphate) in Sample No. 3, further improvement of 400 (lb) was obtained under the Falex baking load. 1100 (lb), 9 in CFC134a atmosphere
0kg / cm ² improved to confirming the effect of 180kg / cm ^2.

That is, a phosphorus compound such as an acidic phosphoric acid ester or an alkylene glycol phosphoric acid ester compound effectively acts as an extreme pressure agent, and is effective as an extreme pressure action for preventing seizure regardless of the presence or absence of Freon 134a. Was proved.

Next, in the Falex test, the load was fixed to 100 (lb) and a continuous test for 120 minutes at maximum was carried out to measure the amount of wear of the pin which is an iron-based test piece. The results are as shown in FIG. 6, where 25 mg was abraded with the oil of Sample No. 4 to which the extreme pressure agent was not added, whereas the oil containing the phosphorus compound was added to Sample No. 7 and Sample. As shown in No. 8, both were as small as 0.4 mg and could be reduced to 1/5 or less. The addition amount of this phosphorus-based compound is the sample No. As shown in Fig. 5, the effect is obtained from around 0.05 wt%, and the effect is improved as the amount is increased, but if it exceeds 10 wt%, the effect of improving the lubricity reaches saturation and becomes economically disadvantageous, which is not practical.

Further, the viscosity of the oil was determined to be 14.9 cS of Sample No. 4.
From t (40 ° C), 56.6 cSt (40
The wear amount also decreased by increasing the viscosity to (° C).

From the above, by adding phosphorus compounds such as acidic phosphoric acid ester, phosphoric acid ester and alkylene glycol phosphoric acid ester to the refrigerating machine oil of the present invention as an extreme pressure agent in an amount of 0.05 to 10 wt%. It was also found that the seizure load, wear resistance and lubricity of the iron-based sliding member can be dramatically improved by adjusting the viscosity of the oil to increase the viscosity instead of adding the extreme pressure agent. In particular, it exhibits excellent performance when a CFC-based refrigerant such as CFC 134a containing no chlorine coexists.

<Embodiment 21> As an embodiment for achieving the fourth object of the present invention, an electrically insulating material used for a hermetic motor of a compressor is used in the coexistence of Freon 134a and the refrigerating machine oil of the present invention. Table 2 shows the results of evaluation of behavior.
And Table 3 demonstrates.

In the evaluation of CFC 134a and refrigerating machine oil, in order to eliminate the influence from the outside, a state of characteristic deterioration of the magnet wire (enamel coated wire) and the insulating film material was observed by a shield tube test.

(1). Insulation characteristics of magnet wire (enamel coated wire): The magnet wire test is a shield tube test at 150 ° C for 40 days for two types of 5% stretched product and twisted pair test piece. The results will be explained below.

[0161]

[Table 2]

Freon 134 shown in the prior art example 3 of Table 1 above.
According to the shield tube test result of the combination of the polyalkylene glycol of the refrigerating machine oil, which is said to be compatible with a, and Freon 134a, the polyester wire (PEW) of sample No. 9 and the ester imide wire (EIW) of sample No. 10 in Table 2 are shown. In the case of -R), crazing (cracking) was generated in all of the 5% stretched lines, and the retention rate of the breakdown voltage of the twisted pair test piece was significantly reduced to 30 to 32%.

On the other hand, the same evaluation was carried out using the glutaric acid (Glut) of Example 17, which is the refrigerator oil of the present invention exemplified in Table 1.
And the composite ester oil of neopentyl glycol (TPG) and Isohekisan acid (i-C ₆₎ Freon 13
As a result of the combination of 4a, the sample of the conventional example described above.
Polyester wire (glass transition temperature: Tg is shown in Table 2) and polyesterimide wire which showed deterioration in Nos. 9 and 10 showed no abnormal appearance as shown in Sample No. 11 and Sample No. 12, Further, the dielectric breakdown voltage retention rate was as high as 95% or more, and it was found that the degree of deterioration of the magnet wire was extremely small. The reason for this is that the refrigerating machine oil of the present invention has a small amount of water held in the initial stage, is excellent in thermal stability, and is difficult to generate an acidic substance that promotes hydrolysis, but has an improving effect. Is what is causing.

Sample No. 13 was obtained by further coating a polyamide-imide layer on the ester-imide wire of Sample No. 12 to form a composite, and Sample No. 14 was polyamide-imide alone (A
IW) coated ones showed good characteristics. In this way, the magnet wire in which the layer having a high glass transition temperature is coated on the layer having a low glass transition temperature, the upper layer coating effectively acts as a protective action against the erosion of the Freon 134a and the refrigerating machine oil. It was found to contribute to the improvement of the reliability of the machine.

(2). Regarding Insulation Properties of Insulating Film: Next, a shield tube test of the insulating film of the motor was performed an insulating strength test at 130 ° C. for 40 days, and the appearance and the tensile strength retention rate were evaluated. Table 3 shows the results.

[0166]

[Table 3]

In the case of a general polyester film (trade name: Lumirror X ₁₀ manufactured by Toray) used for a hermetic motor of a compressor, the conventional polyalkylene glycol oil shown in Sample No. 15 has a protrusion of oligomer component in the oil. Was observed, and the tensile strength retention rate was 83%.

On the other hand, in the combination of the complex ester oil of Example 17 of the present invention and the chlorofluorocarbon 134a, Lumirror X ₁₂ of sample No. 16 and PA-polyamide-imide coated polyester of sample No. 17 were used. 61M
(Hitachi Chemical Co., Ltd. product name), sample No. 18 polyphenylene sulfide (PPS) film, sample No. 1
In any of the polyetheretherketone (PEEK) films of No. 9, no oligomer was projected, and the tensile strength retention rate was excellent at 89% or more.
It has been found that the reliability can be remarkably improved as an electric insulation system of a compressor using a.

That is, in an environment in which Freon 134a and a refrigerating machine oil having two or more ester groups in the molecule of the present invention coexist, a polyester film having a glass transition temperature of 65 ° C. or more, a polyamideimide-coded polyester film and a PPS film, Completing the insulation system of the hermetics motor by properly selecting the PEEK film is a compressor due to the protrusion of oligomer components and the reduction of film strength, which has been a problem with the oil of Conventional Example 3 shown in Sample No. 15. It was found that performance problems and long-term reliability problems in refrigeration systems can be solved.

<Embodiment 22> Next, an embodiment for achieving the fifth object of the present invention will be described. It is known that the control of water in the refrigeration system has an important influence on the cooling performance and the guarantee of the quality of the electric insulating material especially in the refrigeration system that uses a heat exchanger of 0 ° C or less. Therefore, the establishment of technology for the water removal method is an indispensable requirement in the system of the refrigeration system.

The water content of the refrigeration system is as shown in FIG.
In the configured refrigeration cycle, the Freon 134a gas discharged from the compressor 40 is condensed by the heat dissipation in the condenser 41 to become a liquid refrigerant, and the high-temperature, high-pressure liquid refrigerant is cooled by the next expansion mechanism 42 to a low temperature and a low pressure. In the process of becoming wet vapor of the above and being sent to the evaporator 43, a dryer 45 is disposed between the condenser 41 and the expansion mechanism 42, and is adsorbed and removed by a desiccant represented by synthetic zeolite. It is important to properly select the type of the desiccant in the use environment in which the refrigerating machine oil of the present invention and the Freon 134a coexist, and the compatibility thereof will be described based on the examples of Table 4.

[0172]

[Table 4]

All the drying agents tested were Union Showa.
It is a synthetic zeolite called trade name "Molecular Sieves" manufactured by K.K., and various synthetic zeolites are classified according to the adsorption capacity (%) at 25 ° C and carbon dioxide gas partial pressure of 250 mmHg as an index showing the distribution of the pore size to be adsorbed. is there.

The compatibility of the synthetic zeolite Freon 134a with the refrigerating machine oil of the present invention will be described based on the shield tube test results shown in Table 4.

Sample No. 20 (conventional example, trade name 4ANR
The synthetic zeolite mainly composed of sodium salts of aluminic acid and silicic acid shown in G) has a fluorine ion adsorption amount of 1.0.
It was found to be as large as 5%, and problems such as strength reduction and powdering due to the reaction of the synthetic zeolite occur. Also. Sample No. 21 (conventional example, trade name 4AXH-6) and sample No. mainly containing aluminate, sodium and potassium silicate salts.
No. 22 (comparative example, trade name XH-7) has a carbon dioxide gas adsorption capacity of 4.5 to 1.5% and a fluorine ion adsorption amount of 0.5.
It was reduced to 24%. However, the amount of fluorine ion adsorbed is still large for practical use.

Further, sample No. consisting of synthetic zeolite mainly composed of aluminate, potassium and sodium silicates.
23 (Example, trade name XH-600) and sample No. 2
No. 3 (Example, trade name XH-9) had a carbon dioxide gas adsorption capacity of 0.2%, and the fluorine ion adsorption amount was drastically reduced to 0.04%. Fluorine ion adsorption that can be put to practical use is 0.1%
The following shows that all of these samples are sufficiently usable.

The distribution of the pore size of the synthetic zeolite is
Since it becomes a problem to adsorb molecules of Freon 134a and deteriorate the characteristics of the synthetic zeolite itself, in order to control the adsorption amount of fluorine ions to 0.1% or less, the adsorption capacity of carbon dioxide gas should be 1%. It has been confirmed that it is sufficient to use a synthetic zeolite controlled to 0.0% or less.

That is, in a refrigerating apparatus in which flon 134a and a refrigerating machine oil having two or more ester bonds in the molecule of the present invention coexist, a carbon dioxide adsorption capacity of 25 ° C., carbon dioxide partial pressure, At 250 mmHg, silicic acid controlled to 1.0% or less, a synthetic zeolite consisting of an alkaline salt of aluminate, for example, Molecular Sieves XH-600, XH-9 under the trade name of Union Showa Co., Ltd. as a desiccant, It was found that practically, it is possible to effectively remove only water, and there is little influence such as pulverization due to adsorption of fluorine ions and decrease in strength of beads, which is remarkably excellent in practical use.

When the carbon dioxide adsorption capacity is 25 ° C., carbon dioxide partial pressure is 250 mmHg, the lower limit of 1.0% or less is:
It is desirable to be as small as possible, and when this is 0%, F ions are not absorbed and only water is selectively absorbed, which makes an ideal molecular sieve.

[0180]

Since the present invention is configured as described above, it has the following effects.

(1) A refrigeration system comprising at least a compressor, a condenser, an expansion mechanism and an evaporator, which uses a CFC-free refrigerant represented by CFC 134a having a critical temperature of 40 ° C. or higher and which does not contain chlorine. Refrigerator oil viscosity is 2 to 70, preferably 5 to 32 cSt, 100 ° C. when the temperature is 40 ° C.
In this case, the ester oil of the present invention having 2 or more ester bonds in the molecule of 1 to 9 more preferably 2 to 6 cSt is used as a base oil, and a refrigerating machine oil having a lower critical dissolution temperature of 0 ° C or lower or -30 ° C or lower is used. , And the first target is a medium temperature refrigerating device such as a dehumidifier, and the second target is a low temperature refrigerating device such as a refrigerator, whereby the refrigerating machine oil and the refrigerant are separated into two layers in the entire temperature range of the use environment. Since they are well compatible with each other, the lubricating oil film of the compressor shaft and bearing, and the refrigerant heat transfer performance of the heat exchanger are guaranteed, and the performance and reliability of the compressor and refrigeration system are significantly improved. can do.

(2) Further, a phosphate ester-based extreme pressure agent having a hydroxyl group in the molecule and other antiwear agents, acid scavengers, antioxidants, antifoaming agents, etc. are added to the refrigerating machine oil. By using the agent together, the effect of improving the lubricity of the bearing sliding portion of the refrigerant compressor is improved, and the performance and reliability are improved.

(3) In the rotary compressor of the high pressure container system, when the viscosity is 40 ° C., the viscosity is 2 to 70, preferably 5 to 32 cSt, and in the low pressure container system of the reciprocating compressor, the viscosity is At 40 ° C., the refrigerating machine oil of the present invention having two or more ester bonds in each molecule of 2 to 70, and more preferably 5 to 15 cSt, is treated with Freon 13
When used in combination with 4a, it is possible to improve the coefficient of performance indicating the performance of the compressor, reduce the power consumption of the refrigerating apparatus using this, and increase the refrigerating capacity, so-called performance can be improved. is there.

(4) As a motor insulating material of a refrigerant compressor using a Freon-based refrigerant that does not contain chlorine, represented by Freon 134a, an insulating coating winding having a glass transition temperature of 120 ° C or higher and a glass transition temperature of 70 ° C or higher. By using a refrigerating machine oil containing the ester oil of the present invention as a base oil as the refrigerating machine oil, the electric insulating performance and long-term reliability of the refrigerating apparatus can be remarkably improved.

(5) In the dryer that constitutes the refrigeration system, 25
By using a synthetic zeolite composed of silicic acid and an alkali metal aluminate whose carbon dioxide absorption capacity at a carbon dioxide gas partial pressure of 250 mmHg is 1.0% or less, water in the refrigeration cycle can be efficiently separated and adsorbed. , It is possible to eliminate the problem of blockage of the refrigerant pipe caused by the pulverization phenomenon due to the deterioration of the desiccant itself and the abnormal wear phenomenon due to the invasion of the sliding parts of the compressor, and the improvement effect is great in the performance and long-term reliability. is there.

(6) The refrigeration system constructed as described above has a higher ozone depletion potential (OPP), which is a problem in the global environment, than the conventional Freon-based refrigerant gas containing chlorine (eg Freon 12). Zero the global warming potential (GW
P) can be lowered to 0.3 or less.

[Brief description of drawings]

FIG. 1 is a two-layer separation temperature diagram for explaining the compatibility between a refrigerant of Freon 134a and refrigerating machine oil.

FIG. 2 is a characteristic diagram showing the relationship between the amount of water dissolved in various types of refrigerating machine oil and the volume resistivity.

FIG. 3 is a characteristic showing a relationship between an actual viscosity of refrigerating machine oil and a coefficient of performance during a rated operation of a high pressure container type rotary compressor.

FIG. 4 is a characteristic showing a relationship between an actual viscosity and a coefficient of performance during a rated operation of a low pressure container type reciprocating compressor.

FIG. 5 is a characteristic showing a relationship between a Falex test having an iron-based friction sliding surface and a high pressure atmosphere friction test of Freon 134a dissolved oil.

FIG. 6 is a characteristic diagram showing the amount of wear by a Falex test.

FIG. 7 is a longitudinal sectional view of a main part of a hermetic rotary compressor.

FIG. 8 is a longitudinal sectional view of a main part of a compression machine section of a rotary compressor.

FIG. 9 is a refrigeration cycle configuration diagram of the refrigeration apparatus.

FIG. 10 is a refrigeration cycle configuration diagram of a refrigeration apparatus.

[Explanation of symbols]

1 ... Case, 2 ... Cylinder,
3 ... eccentric part, 4 ... rotary shaft, 5
… Main bearing, 6… Sub bearing, 7…
Roller, 8 ... Cylinder groove,
9 ... Spring, 10 ... Vane, 1
3 ... Refrigerating machine oil, 17 ... Shaft hole, 19 ...
Stator, 19a ... Winding, 20 ... Rotor, 22 ... Electric motor, 23 ... Compressor section, 40 ... Compressor, 41 ... Condenser,
42 ... Expansion mechanism, 43 ... Evaporator,
45 ... dryer.

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁶ Identification code Internal reference number FI Technical display area // (C10M 169/04 105: 38 137: 02 137: 04) C10N 20:02 20:04 30 : 06 40:30 (72) Inventor Makoto Tanaka 800 Tomita, Oita-cho, Shimotsuga-gun, Tochigi Hitachi Tochigi Plant (72) Inventor Yoshiharu Honma 4026, Kujimachi, Hitachi, Ibaraki Hitachi, Ltd. Hitachi, Ltd. (72) Inventor Hiroaki Hatake 800 Tomita, Ohira-cho, Shimotsuga-gun, Tochigi Hitachi Tochigi factory (72) Inventor Kōsokabe Hirokatsu 502 Kitsumachi, Tsuchiura, Ibaraki Prefecture (72) Inventor Takuji Nariyoshi 800 Tomita, Ohira-cho, Shimotsuga-gun, Tochigi Prefecture Tochigi Plant, Hitachi, Ltd. (72) Inventor Hiroshi Iwata 502 Jinmachi, Tsuchiura-shi, Ibaraki Co., Ltd. Date falling Mfg Mechanical Engineering Research Laboratory within the

Claims (9)

[Claims] 1. A refrigeration cycle comprising at least a compressor, a condenser, an expansion mechanism and an evaporator, which has a critical temperature of 40 ° C. or higher and contains chlorine-free fluorocarbon refrigerant as a main component. , 2 to 70 when viscosity is 40 ° C
A refrigerating machine comprising a refrigerating machine oil having a base oil of an ester oil of a fatty acid having a cSt of 1 to 9 cSt at 100 ° C and having at least two ester bonds (-O-CO-) in the molecule. 2. A refrigeration cycle composed of at least a compressor, a condenser, an expansion mechanism and an evaporator, wherein at least a Freon 134a is mainly used as a fluorocarbon-based refrigerant having a critical temperature of 40 ° C. or higher and containing no chlorine. CFC-based refrigerant contained as a component and refrigerating machine oil have a viscosity of 2 to 70 cSt at a temperature of 40 ° C. and a viscosity of 1 to 9 cSt at a temperature of 100 ° C. and have at least two ester bonds (—O—CO—) in the molecule. A refrigeration system comprising a refrigerating machine oil containing a fatty acid ester oil as a base oil. 3. In a refrigeration cycle composed of at least a compressor, a condenser, an expansion mechanism and an evaporator, carbon fluoride (FC) and hydrogen are used as a refrigerant containing chlorine-free fluorocarbon refrigerant as a main component. The following general formulas (1) to (5) have at least one fluorocarbon (HFC) fluorocarbon refrigerant and at least two ester bonds (-O-CO-) in the molecule as refrigerating machine oil. A refrigerating apparatus comprising a refrigerating machine oil containing at least one selected from the group of fatty acid ester oils shown as a base oil. [Chemical Formula 1] (R ₁ · CH ₂ ) ₂ · C · (CH ₂ COOR ₂ ) ₂ ··· (1) [Chemical Formula 2] R ₁ · CH ₂ · C · (CH ₂ · COOR ₂ ) ₃ … (2) [Chemical formula 3] C · (CH ₂ —CHOOR ₂ ) ₄ (3) [Chemical formula 4] (R ₂ · OOCH ₂ C) ₃ · C · CH ₂ · O · CH ₂ · C (CH ₂ · COOR ₂ ) ₃ (4) [Chemical 5] However, R ₁ : H or an alkyl group having 1 to 3 carbon atoms R ₂ : an alkyl group having 5 to 12 carbon atoms, and a plurality of kinds having different carbon numbers can be mixed R ₃ : an alkyl group having 1 to ₃ carbon atoms Group n: 0 or an integer of 1 to 5 4. A refrigeration cycle including at least a compressor, a condenser, an expansion mechanism, and an evaporator, which contains at least Freon 134a as a main component of a chlorine-free fluorocarbon-based refrigerant. CFC-based refrigerant and ester bond (-O-C) in the molecule as refrigerating machine oil
A refrigerating machine comprising a refrigerating machine oil containing at least two O-) as a base oil selected from the group consisting of fatty acid ester oils represented by the following general formulas (1) to (5). . [Chemical Formula 6] (R ₁ · CH ₂ ) ₂ · C · (CH ₂ COOR ₂ ) ₂ ··· (1) [Chemical Formula 7] R ₁ · CH ₂ · C · (CH ₂ · COOR ₂ ) ₃ … (2) Embedded image C · (CH ₂ —CHOOR ₂ ) ₄ (3) embedded image (R ₂ · OOCH ₂ C) ₃ · C · CH ₂ · O · CH ₂ · C (CH ₂ · COOR ₂ ) ₃ (4) [Chemical formula 10] However, R ₁ : H or an alkyl group having 1 to 3 carbon atoms R ₂ : an alkyl group having 5 to 12 carbon atoms, and a plurality of kinds having different carbon numbers can be mixed R ₃ : an alkyl group having 1 to ₃ carbon atoms Base n: 0 or an integer of 1 to 5. The refrigeration system according to claim 3, wherein the freon-based refrigerant contains at least freon 134a as a main component. 5. A refrigerating cycle comprising at least a compressor, a condenser, an expansion mechanism, and an evaporator, wherein carbon fluoride (FC) and hydrogen are used as a refrigerant containing chlorine-free carbon fluoride refrigerant as a main component. The following general formulas (1) to (4) have at least one fluorocarbon (HFC) fluorocarbon refrigerant and at least two ester bonds (-O-CO-) in the molecule as refrigerating machine oil. A refrigerating apparatus comprising a refrigerating machine oil containing at least one selected from the group of fatty acid ester oils shown as a base oil. [Chemical formula 11] (R ₁ · CH ₂ ) ₂ · C · (CH ₂ COOR ₂ ) ₂ ··· (1) [Chemical formula 12] R ₁ · CH ₂ · C · (CH ₂ · COOR ₂ ) ₃ … (2) Embedded image C · (CH ₂ —CHOOR ₂ ) ₄ (3) embedded image (R ₂ · OOCH ₂ C) ₃ · C · CH ₂ · O · CH ₂ · C (CH ₂ · COOR ₂ ) ₃ (4) However, R ₁ : H or an alkyl group having 1 to 3 carbon atoms R ₂ : an alkyl group having 5 to 12 carbon atoms, and a plurality of kinds having different carbon numbers can be mixed n: 0 or 1 An integer from ~ 5 6. A refrigeration cycle composed of at least a compressor, a condenser, an expansion mechanism and an evaporator, which has a critical temperature of 40 ° C. or higher and contains chlorine-free fluorocarbon refrigerant as a main component. , 2 to 70 when viscosity is 40 ° C
A refrigerator comprising a refrigerator oil having a cSt of 1 to 9 cSt at 100 ° C and a fatty acid ester oil having at least two ester bonds (-O-CO-) in the molecule as a base oil. 7. A refrigeration cycle composed of at least a compressor, a condenser, an expansion mechanism and an evaporator, which has a critical temperature of 40 ° C. or higher and contains chlorine-free fluorocarbon refrigerant as a main component. , 2 to 70 when viscosity is 40 ° C
cSt, 1-9 cSt at 100 ° C., and a refrigerating machine oil having an ester oil of a fatty acid having at least two ester bonds (—O—CO—) in the molecule as a base oil. A refrigerator comprising at least one kind of oil selected from the group of fatty acid ester oils represented by the following general formulas (1) to (4). [Chemical formula 15] (R ₁ · CH ₂ ) ₂ · C · (CH ₂ COOR ₂ ) ₂ ··· (1) [Chemical formula 16] R ₁ · CH ₂ · C · (CH ₂ · COOR ₂ ) ₃ … (2) Embedded image C · (CH ₂ —CHOOR ₂ ) ₄ (3) embedded image (R ₂ · OOCH ₂ C) ₃ · C · CH ₂ · O · CH ₂ · C (CH ₂ · COOR ₂ ) ₃ (4) However, R ₁ : H or an alkyl group having 1 to 3 carbon atoms R ₂ : an alkyl group having 5 to 12 carbon atoms, and a plurality of kinds having different carbon numbers can be mixed n: 0 or 1 An integer from ~ 5 8. A refrigeration cycle comprising at least a compressor, a condenser, an expansion mechanism and an evaporator, which has a critical temperature of 40 ° C. or higher and contains chlorine-free fluorocarbon refrigerant as a main component. , 2 to 70 when viscosity is 40 ° C
A refrigeration cycle comprising: a cSt; 1-9 cSt at 100 ° C .; and a refrigerating machine oil having a base oil of an ester oil of a fatty acid having at least two ester bonds (—O—CO—) in the molecule. 9. A refrigeration cycle comprising at least a compressor, a condenser, an expansion mechanism and an evaporator, which has a critical temperature of 40.degree. C. or higher and contains chlorine-free fluorocarbon refrigerant as a main component. , 2 to 70 when viscosity is 40 ° C
cSt, 1-9 cSt at 100 ° C., and a refrigerating machine oil having an ester oil of a fatty acid having at least two ester bonds (—O—CO—) in the molecule as a base oil. The refrigeration cycle in which the oil contains at least one selected from the group of fatty acid ester oils represented by the following general formulas (1) to (4). [Chemical Formula 19] (R ₁ · CH ₂ ) ₂ · C · (CH ₂ COOR ₂ ) ₂ ··· (1) embedded image R ₁ · CH ₂ · C · (CH ₂ · COOR ₂ ) ₃ … (2) Embedded image C · (CH ₂ —CHOOR ₂ ) ₄ (3) embedded image (R ₂ · OOCH ₂ C) ₃ · C · CH ₂ · O · CH ₂ · C (CH ₂ · COOR ₂ ) ₃ (4) However, R ₁ : H or an alkyl group having 1 to 3 carbon atoms R ₂ : an alkyl group having 5 to 12 carbon atoms, and a plurality of kinds having different carbon numbers can be mixed n: 0 or 1 An integer from ~ 5