JPH0819430B2 - Refrigerating machine oil composition for refrigerating equipment - Google Patents

Description

TECHNICAL FIELD The present invention relates to a refrigerating machine oil composition for a refrigerating machine using 1,1,1,2-tetrafluoroethane as a refrigerant.

[Prior Art] Various types of refrigerators have been conventionally used. Among them, a so-called vapor compression refrigerator, which uses a refrigerant, has a reciprocating type, a centrifugal type and a rotary type due to the structure of the compressor. It is classified. Among these, the refrigerator with a rotary compressor is small and has a large refrigerating capacity, can exhibit excellent performance even in a high rotation range, and can be operated smoothly and quietly. Therefore, it is widely used in household refrigerators, air conditioners, and the like.

As a refrigerating machine oil used for these, naphthenic mineral oil having a kinematic viscosity at 40 ° C. of 10 to 200 cSt, paraffinic mineral oil, alkylbenzene, polyglycol oil and mixtures thereof or various base oils of these additives were blended. Things are commonly used.

On the other hand, refrigerants for compression refrigerators include trichloromonofluoromethane (CFC 11), dichlorodifluoromethane (CFC 12), and monochlorodifluoromethane (CFC).
22) Alii trichlorotrifluoroethane (Freon 11
Halogen-based refrigerants such as 3), hydrocarbon-based refrigerants such as propane, and inorganic gas-based refrigerants such as ammonia and carbon dioxide are widely used.

Among them, halogen-based refrigerants have been widely used in household refrigerators and air conditioner refrigerators because they are chemically stable, have low toxicity, are nonflammable, and have ideal thermodynamic characteristics.

However, of these, perhalogenocarbons,
In other words, chlorofluorocarbons in which all the hydrocarbon hydrogens have been replaced with halogens are persistent and highly stable, so they do not decompose over a long period of time when released into the atmosphere and form an ozone layer 25-30km above the ground. When it reaches the strong ultraviolet rays from the sun and releases decomposed chlorine atoms, it reacts with ozone and reduces the ozone concentration in the ozone layer. This ozone layer absorbs harmful ultraviolet rays from the sun and protects the organisms on the surface of the earth, and in order to prevent the destruction of the ozone layer by CFCs, the production and consumption of CFCs are being regulated by international treaties. .

Under these circumstances, the United States Environmental Protection Agency (EPA) has determined that 1,1-dichloro-2,2,2-trifluoroethane (CFC-123), 1-chloro-1,2,2,2 -Tetrafluoroethane (CFC-124), 1,2-dichloro-2,2-difluoroethane (CFC-132b), 1-chloro-2,2,2-trifluoroethane (CFC-133a), 1,1, Six types of 1,2-tetrafluoroethane (FC-134) and 1,1-dichloro-1-fluoroethane (CFC-141b) have been proposed as alternative refrigerants.

Of these compounds, 1,1,1,2-tetrafluoroethane has similar thermodynamic properties to dichlorodifluoromethane (CFC12), which has been widely used in refrigerators such as household refrigerators and air conditioners. Therefore, if 1,1,1,2-tetrafluoroethane (FC-134a) is used as the refrigerant, the same performance as before can be obtained without significantly changing the design of those refrigerator systems. You should be able to.

However, for that purpose, the refrigerating machine oil filled in the compressor is entrained in the discharge gas and enters the condenser and the evaporator, so that it is sufficiently dissolved in the reflux refrigerant and circulates in the cycle to return to the compressor. Good oil return is essential.

That is, since it is not uncommon for the temperature to reach -20 to -30 ° C from the expansion valve or the capillary tube, which is the coldest part in the refrigeration cycle, to the evaporator, the refrigerating machine oil is used at such a low temperature. Those which do not cause two-layer separation with the refrigerant are preferred.

Conventionally, as a refrigerating machine oil, a naphthene-based mineral oil, a paraffin-based mineral oil, alkylbenzenes, a mixture thereof or a mixture of these various base oils with an additive is generally used. Regarding these conventional refrigerating machine oils, for example, Japanese Examined Patent Publication Nos. 40-11940, 49-4107, and 49
-13483, Japanese Patent Publication No. 49-13829, Japanese Patent Publication No. 49-19084,
JP-B-52-39509, JP-B-52-43722, JP-B-53-17
602, JP-A-46-4532, JP-A-48-606, and JP-A-49
-47498, JP-A-51-22971, JP-A-52-28503,
It is described in JP-A-52-54707 and JP-A-53-88007. However, these conventional refrigerating machine oils are 1,1, which are alternative refrigerants for dichlorodifluoromethane (CFC12).
Since it has almost no compatibility with 1,2-tetrafluoroethane (FC-134a), when used in combination with 1,1,1,2-tetrafluoroethane, it causes two-layer separation at room temperature, and However, the most important problem is that the oil returns poorly and the refrigeration efficiency decreases or the lubricity becomes poor, causing various practical problems such as seizure of the compressor, which makes it unusable. Polyglycols are also known as refrigerating machine oils having a high viscosity index, for example, Japanese Examined Patent Publication No. 57-42119.
It is described in JP-B-61-52880 and JP-A-57-51795. However, since the polyglycol oils specifically disclosed in these prior arts are still not sufficiently compatible with 1,1,1,2-tetrafluoroethane, the same problems as described above occur and they cannot be practically used.

[Problems to be Solved by the Invention] As a result of repeated studies by the present inventors to develop a refrigerating machine oil composition for a compression type refrigerating machine using 1,1,1,2-tetrafluoroethane as a refrigerant, It was found that when a polyglycol oil having a limited structure and properties is used as a base oil, a refrigerator composition having excellent performance that cannot be obtained with other base oils can be obtained, and the present invention has been completed. Came to do.

The present invention is suitable for use in a compression type refrigerating machine using 1,1,1,2-tetrafluoroethane as a refrigerant,
In particular, it is an object of the present invention to provide a refrigerating machine oil composition for a refrigerating machine which does not separate from a refrigerant at low temperatures and has good lubricity, hermeticity and stability.

Means for Solving the Problems The present invention provides [I] a general formula HOR _{1 a} OH. The kinematic viscosity at 100 ° C is 2 to (10 + 120
α) cSt is polyoxyalkylene glycol, and [II] general formula The kinematic viscosity at 100 ° C is 2 to (10 + 120
β) cSt selected from the group consisting of polyoxyalkylene glycol glycerol ethers and having a pour point of −
A refrigerating machine oil composition for a refrigerating machine using 1,1,1,2-tetrafluoroethane as a refrigerant, characterized by using a polyglycol oil having a temperature of 10 ° C. or lower as a base oil (hereinafter referred to as “specific invention”). ) Is provided.

Further, the present invention uses the polyglycol oil of the specified invention as a base oil, and further comprises (A) the general formula based on 100 parts by weight of the base oil. The present invention provides a refrigerating machine oil composition for a refrigerating machine using 1,1,1,2-tetrafluoroethane as a refrigerant, which comprises 0.1 to 5.0 parts by weight of the phosphate represented by the formula (1) as an essential component.

Further, the present invention uses the polyglycol oil of the specified invention as a base oil, and further comprises (A) the general formula based on 100 parts by weight of the base oil. 0.1 to 5.0 parts by weight of a phosphate represented by: and (B) at least one selected from the group consisting of (i) phenylglycidyl ether type epoxy compound, (ii) epoxidized fatty acid monoester, and (iii) epoxidized vegetable oil The present invention provides a refrigerator oil composition for a refrigerating machine using 1,1,1,2-tetrafluoroethane as a refrigerant, which comprises 0.1 to 5.0 parts by weight of the epoxy compound as an essential component.

The base oil of the refrigerator oil composition for a refrigerating machine of the present invention is [I] _a polyoxyalkylene glycol represented by the general formula HOR _{1 a} OH, and [II] a general formula Is one or more polyglycol oils selected from the group consisting of polyoxyalkylene glycol glycerol ethers represented by

In the above formula, a represents an integer of 5 to 50, b, c and d are integers of 3 to 40, respectively, and 9 ≦ b + c +
The number is d ≦ 50. Further, R ₁ , R ₂ , R ₃ and R ₄ represent an alkylene group having 2 to ₄ carbon atoms. Specific examples of R ₁ , R ₂ , R ₃ and R ₄ include an ethylene group (—CH ₂ CH ₂ —), Trimethylene group _{(-CH 2 CH 2 CH 2 -} ), Tetramethylene group _{(-CH 2 CH 2 CH 2 CH} 2 -) and the like, ethylene group. Among them, propylene group, butylene group, tetramethylene group being more preferred.

Further, in the [I] polyoxyalkylene glycol and [II] polyoxyalkylene glycol glycerol ether of the present invention, alkylene groups having different carbon numbers may be present in one molecule, that is, oxyalkylene groups having different carbon numbers may be present. It may be a random copolymer or a block copolymer, but in [I] polyoxyalkylene glycol, the ratio of (the number of —OR ₁ — groups where R ₁ is an ethylene group) / a in one molecule is ,
In addition, in the [II] polyoxyalkylene glycol glycerol ether, (OR ₂ — group, —OR ₃ — group and —OR ₄ — group in which R ₂ , R ₃ and R ₄ are ethylene groups in one molecule are
The ratio of (total number of groups) / (b + c + d) is 0 to 0.8, respectively.
It is necessary to be. If this ratio exceeds 0.8, the refrigerating machine oil becomes solid at room temperature or its pour point becomes high, which is not preferable.

The polyglycol oil of the present invention has a pour point of -10 ° C or lower, preferably -20 to -50 ° C, and a kinematic viscosity at 100 ° C of 2 to (10 + 120α) cSt or 2 to (10 + 120).
β) cSt, preferably 3 to (7 + 120α) cSt or 3 to
It must be in the range of (7 + 120β) cSt. If the pour point exceeds -10 ° C, the refrigerator oil may solidify in the refrigeration system at low temperatures, which is not preferable. Also 10
If the kinematic viscosity at 0 ° C is less than 2 cSt, the compressor cannot maintain its hermeticity, while the kinematic viscosity is (10 + 120
When α) cSt or (10 + 120β) cSt is exceeded, the solubility with the refrigerant 1,1,1,2-tetrafluoroethane becomes poor and two layers are separated at low temperature, which is not preferable.

Further, in the present invention, as the polyglycol oil, those having an average molecular weight of 300 to 4000 are usually preferably used, and those having an average molecular weight of 500 to 3000 are more preferably used.

The refrigerating machine oil composition for a refrigerating machine of the present invention is one or two selected from the group consisting of the above-mentioned [I] polyoxyalkylene glycol and [II] polyoxyalkylene glycol glycerol ether which are base oils.
Refrigerating machine oil for a refrigerating machine that uses 1,1,1,2-tetrafluoroethane as a refrigerant even if one or more polyglycol oils are used alone, that is, without adding any additives. Shows excellent performance as, but in order to further improve its wear resistance and load resistance (anti-seizure property), (A) general formula It is preferable to add a phosphate represented by In the formula, R ₅ represents an alkyl group having 1 to 3 carbon atoms, preferably a methyl group, and e represents an integer of 0 to 2, preferably 0 to 1. As R ₅ , specifically, for example,
Examples thereof include a methyl group, an ethyl group and a propyl group.

As the phosphate as the component (A), specifically, triphenyl phosphate, tritolyl phosphate (tricresyl phosphate), and a mixture thereof are preferably used.

When the component (A) is used in the refrigerating machine oil composition for a refrigerating machine of the present invention in order to further improve its wear resistance and load resistance, its content is from 0.1 to 100 parts by weight of the base oil. The amount is 5.0 parts by weight, preferably 0.2 to 2.0 parts by weight. When the compounding amount of the component (A) does not reach this range, the effect of improving the wear resistance and load resistance due to the compounding of the component (A) is poor. On the other hand, when the compounding amount of the component (A) exceeds this range, Each of these is not preferable because the thermal stability may be reduced and corrosion of metals in the refrigeration system may occur.

In the refrigerating machine oil composition for a refrigerating machine of the present invention, by adding a specific amount of the component (A) as an essential component as described above, its wear resistance and load resistance are improved. When copper or a copper alloy is used for the above, there is a risk that the combination of the component (A) may cause corrosion of those metals.

Therefore, when the component (A) is blended, for the purpose of improving the overall performance as a refrigerating machine oil for a refrigerating machine,
Furthermore, it is preferable to blend at least one epoxy compound selected from the group consisting of (B) (i) phenyl glycidyl ether type epoxy compound, (ii) epoxidized fatty acid monoester, and (iii) epoxidized vegetable oil.

Examples of the (i) phenyl glycidyl ether type epoxy compound include phenyl glycidyl ether and alkyl phenyl glycidyl ether.
The alkylphenyl glycidyl ether referred to here is
A compound having 1 to 3 alkyl groups having 1 to 13 carbon atoms, and particularly having 1 alkyl group having 4 to 10 carbon atoms, for example, butylphenylglycidyl ether, pentylphenylglycidylether, hexylphenylglycidylether, heptyl Phenyl glycidyl ether, octyl phenyl glycidyl ether, nonyl phenyl glycidyl ether, and decyl phenyl glycidyl ether are preferred.

Further, (ii) as the epoxidized fatty acid monoester,
Epoxidized fatty acid having 12 to 20 carbon atoms and 1 to 8 carbon atoms
And an ester with an alcohol or phenol or an alkylphenol. Particularly, butyl, hexyl, benzyl, cyclohexyl, methoxyethyl, octyl, phenyl and butylphenyl esters of epoxystearic acid are preferably used.

Examples of (iii) the epoxidized vegetable oil include epoxy compounds of vegetable oils such as soybean oil, linseed oil, and cottonseed oil.

Of these epoxy compounds (i) to (iii), preferred as the component (B) are phenyl glycidyl ether type epoxy compounds and epoxidized fatty acid monoesters. Among them, phenyl glycidyl ether type epoxy compounds are more preferable, and phenyl glycidyl ether, butyl phenyl glycidyl ether and mixtures thereof are particularly preferable.

In the refrigerator oil composition for a refrigerating machine of the present invention,
When the component (B) is used as an essential component in addition to the component (A), the blending amount of the component (B) is 0.1 to 5.0 parts by weight, preferably 0.2 to 2.0 parts by weight, relative to 100 parts by weight of the base oil. It is a department. If the blending amount of the component (B) does not reach this range, the effect of improving the corrosion prevention by the blending of the component (B) is poor, while if the blending amount of the component (B) exceeds this range, wear resistance and resistance It is not preferable because it adversely affects loadability.

For the refrigerating machine oil composition for a refrigerating machine of the present invention, in order to further enhance its performance, conventionally known refrigerating machine oil additives such as phenol-based, amine-based antioxidants, and sulfur-based oily properties An improving agent, a silicone-based defoaming agent, a metal deactivator such as benzotriazole, and a phosphite-based hydrogen chloride scavenger can be blended alone or in combination.

The refrigerating machine oil composition for a refrigerating machine using 1,1,1,2-tetrafluoroethane as a refrigerant of the present invention is particularly preferably used for a refrigerating machine having a rotary (rotary) compressor. However, it can be preferably used in other refrigerating and refrigerating apparatuses having other reciprocating or centrifugal compressors.

The refrigerator oil composition for a refrigerator-freezer of the present invention is a refrigerator,
It can be used for refrigerators, freezers, refrigerators, vending machines, showcases, cooling devices for chemical plants, dehumidifiers, etc.

[Examples of the Invention] Hereinafter, the contents of the present invention will be described more specifically with reference to Examples and Comparative Examples.

Examples 1 to 6 and Comparative Examples 1 to 5 Table 1 shows normality of the base oil of the refrigerating machine oil used in Examples and Comparative Examples.

In order to measure the low-temperature separability of the refrigerating machine oil (Examples 1 to 6) according to the present invention and the refrigerant, 10% of the base oil of Examples 1 to 6 was added to 1,1,1,2-tetrafluoroethane as a refrigerant. , 20,30,40,
A mixed solution containing 50 and 70 parts by weight was prepared and gradually cooled from room temperature, and the temperature at which the mixed solution became cloudy or separated into two layers, that is, the two-layer separation temperature was determined. The results are shown in Table 2.

Further, for comparison, Comparative Examples 1 to 5 which are outside the scope of the present invention
The same test as above was performed for the base oil of No. 2 above to determine the two-layer separation temperature. The results are also shown in Table 2.

Examples 7 to 16 Refrigerating machine oil compositions according to the present invention were obtained with the compositions shown in Table 3. Note that Examples 7 to 11 are specific inventions (claim 1),
Embodiments 12 and 13 relate to the invention of claim 2, and Embodiments 14 to 16 relate to the invention of claim 3.

The performances of these compositions were evaluated by the test methods shown below, and the results are also shown in Table 3.

(Falex seizure load test) According to ASTM D3233, initial oil temperature 25 ℃, running-in 250
The seizure load was measured under the conditions of lb and 5 minutes.

(Shield tube test) An equal volume mixture of oil and refrigerant (1,1,1,2-tetrafluoroethane) was sealed in a glass tube with copper and iron catalysts,
Discoloration of the oil and the catalyst after heating at 1000C for 1000 hours was observed and measured.

The degree of discoloration of the oil was classified into 12 levels, with black brown being 11 and colorless being 0. Further, discoloration of the metal catalyst is not a problem as long as it loses gloss, but it is not good if the iron catalyst is plated with copper.

As is clear from the results of the two-layer separation temperature in Table 2, the refrigerating machine oil according to the present invention shows very good compatibility with the refrigerant 1,1,1,2-tetrafluoroethane even at low temperatures. On the other hand, the mineral oils of Comparative Examples 1 and 2 and the alkylbenzenes and polyglycol oils, the diethers of Comparative Example 3 and the polyglycol oils of Comparative Examples 4 and 5 are not in the viscosity range of the present invention. In the case of one, it causes two-layer separation from the refrigerant at room temperature and cannot be put to practical use.

Further, as is clear from the results of the performance evaluation test in Table 3, the refrigerating machine oils of Examples 7 to 11 according to the specific invention of the present invention show excellent performances in the Falex test and the shield tube test. The compositions of Examples 12 and 13 according to the invention have a significantly improved seizure load in the Falex test due to the incorporation of the component (A), and are refrigerating machine oils having more excellent lubricity. Furthermore, the compositions of Examples 14 to 16 according to the invention of claim 3 of the present invention have improved shield tube test results over the compositions of Examples 12 and 13 while maintaining excellent lubricity. In particular, the compositions of Examples 14 to 16 have a better shield tube test result than the refrigerating machine oils of Examples 7 to 11 consisting of only the base oil, and the effect of blending the component (B) on the stability of the refrigerating machine oil. Is clearly shown.

[Effects of the Invention] As described above, the composition of the present invention uses 1,1,1,
A refrigerating machine oil composition for a refrigerating machine, which is suitable for use in a refrigerating machine using 2-tetrafluoroethane, does not separate from a refrigerant at a low temperature, and has good lubricity, sealing property and stability.

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Claims (3)

[Claims] 1. [I] General formula The kinematic viscosity at 100 ° C is 2 to (10 + 120
α) cSt is polyoxyalkylene glycol, and [II] general formula The kinematic viscosity at 100 ° C is 2 to (10 + 120
β) cSt selected from the group consisting of polyoxyalkylene glycol glycerol ethers and having a pour point of −
A refrigerating machine oil composition for a refrigerating machine using 1,1,1,2-tetrafluoroethane as a refrigerant, characterized by using a polyglycol oil having a temperature of 10 ° C or lower as a base oil. 2. General formula (A) for 100 parts by weight of base oil The refrigerator oil composition for a refrigerating machine according to claim 1, which comprises 0.1 to 5.0 parts by weight of the phosphate represented by the formula (1) as an essential component. 3. A general formula for (A) with respect to 100 parts by weight of base oil. 0.1 to 5.0 parts by weight of a phosphate represented by: and (B) at least one selected from the group consisting of (i) phenylglycidyl ether type epoxy compound, (ii) epoxidized fatty acid monoester, and (iii) epoxidized vegetable oil The refrigerator oil composition for a refrigerating machine according to claim 1, wherein 0.1 to 5.0 parts by weight of the epoxy compound is blended as an essential component.