JP2580448B2 - Lubricating oil for chlorofluorocarbon compressor, composition for chlorofluorocarbon compressor in which said lubricating oil is mixed with chlorofluorocarbon refrigerant, and method of lubricating chlorofluorocarbon compressor using said lubricating oil - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a lubricating oil for a compressor using CFC as a refrigerant, a composition for a CFC compressor comprising a CFC refrigerant and a lubricating oil, and a lubrication method. In particular, the present invention relates to a hydrofluorocarbon which does not contain chlorine, such as 1,1,1,2-tetrafluoroethane (HFC-134a) and 1,1,2,2-tetrafluoroethane (HFC-134). ), 1,1-difluoroethane (HFC-152a), difluoromethane (HFC-32), pentafluoroethane (HFC-1
25) and the like (hereinafter, these are referred to as HFC134a, etc.) and are applied when compressing a hydrogen-containing Freon refrigerant, and exhibit particularly excellent lubricity.

[0002]

2. Description of the Related Art Conventionally, for air conditioners and car air conditioners, a fluorocarbon refrigerant containing fluorine and chlorine as constituent elements, such as trichloromonofluoromethane (CFC-11), dichlorodifluoromethane (CFC-12), and monochlorofluorofluorocarbon. Although a chlorine-containing Freon refrigerant such as methane (HCFC-22) is used, there is a problem of environmental pollution. For this reason, a hydrogen-containing Freon refrigerant such as HFC-134a has been spotlighted as a new type of refrigerant.

On the other hand, regarding lubricating oil for CFC compressors,
Conventionally, many mineral oil-based and synthetic oil-based ones are known,
These compounds have poor compatibility with the above-mentioned HFC-134a and the like and cannot be used. Recently, many polyalkylene polyol compounds having excellent compatibility with the HFC-134a and the like have been proposed as lubricating oils.

For example, polyoxypropylene glycol monoalkyl ether having an average molecular weight of 300 to 1200 (Japanese Patent Laid-Open No. 1-259093), and an average molecular weight of 300 to 7
No. 00, polyoxypropylene glycol dialkyl ether (JP-A-1-259904), polyoxyethylene polyoxypropylene copolymer monoalkyl ether (JP-A-55-58298, JP-B-61-52880,
JP-A-1-259095). Also, a specific polyalkylene glycol monoalkyl ether (JP-A-2-84491) as a lubricating oil composition for a freezing and refrigeration apparatus,
Refrigeration comprising a polyalkylene glycol derivative such as dimethyl ether in which the hydroxyl group at the terminal of the polyalkylene glycol is methyl etherified (JP-A-2-305893), a specific polyether polyol having an average molecular weight of 400 to 5000, and a specific ester. Lubricating oil (U
S4851144), a composition for a refrigerator which is a random polyoxyalkylene glycol (JP-A-3-10349)
6, JP-A-3-103497, and US Pat. No. 4,971,712).

[0005]

A currently known polyalkylene polyol-based lubricating oil for refrigerators is HFC-1.
When used in the presence of 34a or the like, the compatibility is quite excellent, but the lubricity is not always satisfactory, and further improvement in performance is desired. Accordingly, an object of the present invention is to provide a grease lubricating oil having excellent compatibility in a wide temperature range and exhibiting even more excellent lubricating properties, particularly in an atmosphere of a hydrogen-containing Freon refrigerant containing no chlorine such as HFC-134a. Is to do. Still another object of the present invention is to provide a lubricating oil which can be used without any problem under the conditions using a conventional chlorofluorocarbon refrigerant. Still another object is to provide a compressor composition in which a CFC refrigerant and a specific lubricating oil are mixed, and to provide a lubricating method using a specific lubricating oil.

[0006]

Means for Solving the Problems The present inventors have studied in detail the structure and lubricity of a polyalkylene polyol compound, and have found that a compound having a specific structure exhibits extremely excellent lubricity and compatibility. As a result, the present invention has been completed.

[0007] The present invention is a lubricating oil for a CFC compressor, which comprises one or more compounds represented by the following general formula (I) as a main component. R ₁ -[-O- (R ₂ O) _y- (CH ₂ CH ₂ O) _z -H] _x (I) (In the formula (I), R ₁ has 1 to 8 carbon atoms having one hydroxyl group. R ₂ represents a hydrocarbon residue of an alcohol;
-4 represents a branched alkylene group, x represents an integer of 1, and y and z each independently represent an integer. Further, the R ₂ O unit and the CH ₂ CH ₂ O unit are block-polymerized in the arrangement order of the formula (I), and satisfy 0 <z / (y + z) ≦ 0.4. )

Further, the present invention relates to a lubricating oil for chlorofluorocarbon compressors comprising, as a main component, a mixture of a compound represented by the following general formula (I ') and a compound represented by the following general formula (II). R ₁ -[— O— (R ₂ O) _y — (CH ₂ CH ₂ O) _z —H] _x (I ′) (In the formula (I ′), R ₁ represents a carbon number having ₁ to 4 hydroxyl groups. A hydrocarbon residue of an alcohol of 1-8, R ₂ represents a branched alkylene group having 3-4 carbon atoms, x represents an integer of 1-4, and y and z each independently represent an integer.
_{The 2} O unit and the CH ₂ CH ₂ O unit are represented by the formula (I ′)
And O <z / (y + z)
Satisfies ≦ 0.5. ) R ₃ - _{[- O- (R 4 O) m} - (CH 2 CH 2 O) n -R 5 ] in _L (II) (Formula (II), the number of carbon atoms _{R 3} is having 1-4 hydroxyl groups A hydrocarbon residue of an alcohol having 1-8, R ₄ is a branched alkylene group having 3-4 carbon atoms, R ₅ is an alkyl group having 1-8 carbon atoms, 1 is an integer of 1-4, m and n are And each independently represents an integer, and an R ₄ O unit and CH ₂
The CH ₂ O unit is block-polymerized and 0 <n / (m
+ N) ≦ 0.5. )

The present invention also relates to a composition for a compressor comprising a mixture of the above-mentioned lubricating oil for a CFC compressor and a CFC refrigerant. Further, the present invention relates to a method for lubricating a CFC compressor using the CFC compressor lubricating oil in a CFC compressor using the above CFC refrigerant.

The polyoxyalkylene monoalkyl ether used in the present invention is represented by the following general formula (I):
An oxyalkylene group represented by —R ₂ O— and —CH ₂ C
An oxyethylene group represented by H ₂ O— (hereinafter abbreviated as EO) has a structure in which each is subjected to block polymerization.

[0011] The _-R 2 O-in _{R 2} is a branched alkylene group having 3-4 carbon atoms. Specifically, -CH _(CH 3)
CH ₂ —, —CH ₂ CH (CH ₃ ) —, —CH (C ₂ H
_{5) CH 2 -, - CH} 2 CH (C 2 H 5) -, - CH
_{(CH 3) CH (CH 3} ) -, - CH (CH 3) CH 2
CH _2- and the like can be mentioned. Further, at least a part of hydrogen of these branched alkylene groups may be substituted with fluorine. As such fluorine-substituted alkylene group _{-CH 2 CH (CF 3) -} , - CH (CF 3) CH 2
-And the like. R ₂ of the present invention has 3 carbon atoms
The branched alkylene group of -4 also includes such a fluorine-substituted branched alkylene group.

The polyoxyalkyleneoxyethylene monoalkyl ether used in the present invention is, as shown by the general formula (I), a polymerized portion of a branched alkylene oxide having 3 to 4 carbon atoms (hereinafter referred to as an R ₂ O unit; ₂ O) _y
) And a polymerized portion of ethylene oxide (hereinafter referred to as E
O, and represented by (EO) _z ), and the entire arrangement is represented by R ₁ , oxygen O, (R ₂ O) _y , (EO) as shown in the general formula (I). ) _Z , hydrogen H
In the order of The arrangement of the above R ₂ O units and EO units is reversed, or improvement of lubricity cannot be achieved with a random copolymer. This arrangement should be recognized as an important feature of the present invention, which significantly enhances the lubricity previously lacking.

The degree of polymerization y of R ₂ O and the degree of polymerization z of EO in the polyoxyalkylene monoalkyl ether used in the present invention are each an integer of 1 or more, and z / (y +
The ratio (mol) of z) needs to be 0.4 or less, preferably 0.3 or less, more preferably 0.25 or less. The z / (y + z) ratio is determined in terms of lubricity, moisture absorption resistance, low-temperature fluidity, and compatibility with Freon refrigerant. As the z / (y + z) ratio decreases, the moisture absorption resistance particularly improves. . The lubricity differs greatly depending on the presence or absence of EO. If one or more units of EO are contained, good lubricity can be obtained. However, z containing no unit of EO
In the case of = 0, that is, in the case where the z / (y + z) ratio is zero, good lubricity cannot be obtained. Therefore, z / (y
+ Z) The lower limit of the ratio is when one unit of EO is contained in one molecule of polyoxyalkylene monoalkyl ether (z = 1
And the value varies depending on the molecular weight of the ether. For example, in the general formula (I), when R ₁ is a methyl group and R ₂ O is an oxypropylene group and the molecular weight is about 1000, the z / (y + z) ratio is about 0.06; It is about 0.04 at 1500, about 0.03 at about 2000, and about 0.02 at about 3000.
In order to obtain better lubricity, it is necessary to use E in one molecule of ether.
The z / (y + z) ratio was increased to 0.05 by increasing the degree of polymerization of O.
Above, especially 0.1 or more. However,
If the ratio exceeds 0.5, problems such as deterioration of moisture absorption resistance, decrease in compatibility with Freon refrigerant, and increase in pour point occur, and thus cannot be used in the present invention. Further, it contains one or more units of EO and has a z / (y + z) ratio of 0.4.
Even within the following range, the random copolymer or the arrangement order of (R ₂ O) y and (EO) _{z is} the same as that of the general formula (I)
Those that do not satisfy the above cannot improve the lubricity.

The viscosity of the block copolymerized polyoxyalkyleneoxyethylene monoalkyl ether lubricating oil of the present invention or for use in a CFC compressor used in the present invention depends on the type of refrigerant, the type of refrigerator and the operating conditions. hand,
It may be appropriately selected in consideration of lubricity, sealing properties, wear resistance, energy saving, and the like, but generally the kinematic viscosity at 100 ° C. is preferably in the range of 2 to 30 cSt, particularly preferably 4 to 30 cSt. If the viscosity is too low, lubricity will be insufficient. Therefore, the average molecular weight also depends on the viscosity, ie, 300 to 3
000, preferably 500 to 2500, more preferably 700 to 2500, which can be adjusted by appropriately controlling the x, y and z. Furthermore, it can be adjusted by appropriately mixing polyoxyalkyleneoxyethylene monoalkyl ethers having different molecular weights.

Two or more compounds represented by the general formula (I) can be used as a mixture. For example, if the kinematic viscosity is 2
５5 cSt (100 ° C.) and 10-30 cSt are mixed and adjusted to the required viscosity, or 2-10 cSt.
(100 ° C.) and 15 to 50 cSt can be mixed and adjusted to an appropriate value of, for example, a viscosity of 5 to 25 cSt. Further, a compound of the general formula (I) having a z / (z + y) ratio of 0.6 and a compound having the ratio of 0.05 to 0.4 are mixed and adjusted to 0.1 to 0.5 for use. be able to. However, in this case, the mixing ratio of the compound having az / (z + y) ratio exceeding 0.5 is preferably 50% or less of the whole in view of improving lubricity.

R ₁ in the general formula (I) has 1 to 8 carbon atoms.
Is a saturated hydrocarbon residue of a monohydric aliphatic alcohol.
If the alkyl group of R ₁ has 9 or more carbon atoms, compatibility with the chlorofluorocarbon refrigerant is completely unfavorable. Therefore, the number of carbon atoms of the alkyl group may be selected from those having 8 or less according to the application and use conditions. However, when the number of carbon atoms is 6 to 8, the two-layer separation temperature on the high temperature side is slightly lowered. More preferably 1 to 4 carbon atoms,
It is more preferable to select 1 or 2. Specifically, in the case of monovalent, a methyl group, an ethyl group, a propyl group, a butyl group, an isobutyl group, a pentyl group, a hexyl group and the like can be mentioned. In HFC-134a and the like, a methyl group to a butyl group are more preferable, and a methyl group and an ethyl group are particularly preferable. Further, the alkyl group may be substituted by fluorine. Examples of such a group include a trifluoromethyl group and a trifluoromethylethyl group. In addition, in the chlorine-containing Freon refrigerant, even a carbon number of 1 to 8 can be used without any problem.

The polyoxyalkylene monoalkyl ether of the block copolymer used in the present invention is produced by a known method conventionally known as production of a block copolymer. For example, a monohydric alcohol having 1 to 4 carbon atoms and propylene oxide are polymerized in the presence of a polymerization initiator such as an alkali metal salt to obtain polyoxypropylene glycol monoalkyl ether, and unreacted propylene oxide is removed. Is polymerized to obtain polyoxypropylene polyoxyethylene monoalkyl ether. If necessary, unreacted raw materials are distilled off, and it is more preferable to purify the clay. The ratio of R ₂ O and EO or the degree of polymerization can be adjusted by the amount of the raw materials. The same applies when other alcohols are used as starting materials.

Further, a mixture of the compound of the following general formula (I ') and the compound of the general formula (II) is excellent in lubricating properties, moisture absorption resistance, and overall performance of compatibility with a chlorofluorocarbon refrigerant. R ₁ , — [— O— (R ₂ O) _y — (CH ₂ CH ₂ O) _z —H] _x (I ′) (In the formula (I ′), R ₁ represents a carbon atom having ₁ to 4 hydroxyl groups. A hydrocarbon residue of an alcohol having the formula 1-8, R ₂ represents a branched alkylene group having 3-4 carbon atoms, x represents an integer of 1-4, and y and z each independently represent an integer. R
_{The 2} O unit and the CH ₂ CH ₂ O unit are represented by the formula (I ′)
And O <z / (y + z)
Satisfies ≦ 0.5. ) R ₃ - _{[- O- (R 4 O) m} - (CH 2 CH 2 O) n -R 5 ] symbols in _L (II) (formula (II), those in the description of the formula (II) Used in the same sense as

In the general formula (I '), R ₁ represents a hydrocarbon residue of an alcohol having ₁ to 4 carbon atoms having ₁ to 4 hydroxyl groups, and x represents an integer of ₁ to 4 in the formula (I'). , Z / (y
+ Z) has the same meaning as in the general formula (I), except that 0 ≦ z / (y + z) ≦ 0.5. Therefore, when R ₁ is a hydrocarbon residue of an alcohol having 1 to 8 carbon atoms having _one hydroxyl group, it is the same as the compound of the general formula (I), and also has 1 to 4 carbon atoms having 2 to 4 hydroxyl groups. R ₁ as a hydrocarbon residue of the alcohol of -8 is ethylene glycol, propylene glycol, diethylene glycol,
1,3 propanediol, 1,2 butanediol, 1,
6-hexanediol, 2-ethyl-1,3-hexanediol, neopentyl glycol type 2 having 5-8 carbon atoms
Examples thereof include hydrocarbon residues derived from polyhydric alcohols, trimethylolethane, trimethylolpropane, trimethylolbutane, glycerin, 3-methyl-1,3,5-pentanetriol, pentaeristol, and the like. The hydroxyl groups of these polyhydric alcohols are substantially completely etherified with R ₂ O and EO in the form of a block copolymer in the same manner as the above-mentioned monohydric alcohols.
Therefore, x in the general formula (I ′) takes a value corresponding to the hydroxyl group of the original alcohol, that is, 1 for monohydric alcohol, 2 for dihydric alcohol, 3 for trihydric alcohol, 4 for tetrahydric alcohol. It is.

When the compound of the general formula (II) is mixed, the lubricating property is slightly lower than that of the compound of the general formula (I) alone, but the lubricating property is sufficiently excellent. Improves moisture absorption resistance. Therefore, this mixture is a lubricating oil for a CFC compressor having excellent overall properties such as lubricity, moisture absorption resistance, and compatibility with a CFC refrigerant. In the general formula (II), R ₃ , R ₄ , 1, m, and n represent R ₁ , R ₂ , x, y in the corresponding general formula (I), respectively.
And z are the same as those of formula (I).
For almost the same reason. R ₅ represents an alkyl group having 1 to 8 carbon atoms. If the number of carbon atoms exceeds 8, the compatibility with the chlorofluorocarbon refrigerant is lowered, and R ₅ cannot be used. Considering lubricity, 4
The number is more preferably, and more preferably a methyl group or an ethyl group. Also, the R ₄ O unit and CH ₂ CH
_The 2O unit is a block polymer, and the order of arrangement may be either. However, when R ₃ is a divalent or higher valent alcohol residue, the block may be arranged in the order of general formula (II). Polymerized ones are preferred. The mixture is a mixture obtained by mixing the compound of the general formula (I ') and the compound of the general formula (II) at an arbitrary ratio, and has a general property such as lubricity, moisture absorption resistance, and compatibility with a CFC refrigerant. From the viewpoint of performance, the compound of the general formula (I ′) is preferably contained in an amount of 25 wt% or more, more preferably 30 wt% or more, and particularly preferably 4 wt% or more.
0 wt% or more. The viscosity of the CFC compressor lubricating oil composed of this mixture is generally 100 ° C., as in the case of the CFC compressor composed of the compound of the general formula (I) described above.
Has a kinematic viscosity of 2 to 30 cSt, particularly 4 to 30 cS.
The range of t is preferable, and the adjustment of the viscosity is performed by the general formula (I ′)
X, y, and z, and 1, m, and n of the general formula (II) can be appropriately controlled, or can be adjusted by appropriately mixing the compounds having different viscosities.

Further, the block copolymer or the block copolymer mixture of the present invention and other polyoxyalkylene glycol, polyoxyalkylene glycol diether,
Polyether oil such as polyoxyalkylene glycol glycerol ether, or polyol ester,
It can be used by mixing with an ester oil such as a complex ester. In this case, the proportion of the block copolymer or block copolymer mixture of the present invention may be adjusted to 50% by volume or more, preferably 60% by volume or more.

Further, if necessary, for example, di-ter
Phenols such as t-butyl-cresol, phenyl-α-naphthylamine, N, N′di (2-naphthyl)-
amine-based antioxidants such as p-phenylenediamine;
Zinc dithiophosphate, phosphate ester, phosphite,
Wear inhibitors such as chlorinated phosphates, molybdenum phosphate and molybdenum carbamate; sulfur-based agents such as chlorinated paraffin and sulfide oil; extreme pressure agents such as lead soap; oil-based agents such as fatty acids; and silicone-based defoamers It is also possible to add a predetermined amount of a metal deactivator such as benzotriazole or an additive such as an epoxy compound alone or in combination of several kinds. The lubricating oil of the present invention is used to fill a CFC compressor in the form of a mixture mixed with a CFC refrigerant, particularly a CFC-free refrigerant containing no chlorine such as HFC-134a at an arbitrary ratio, and exhibits excellent lubricity. . The mixing ratio (weight) of lubricating oil and Freon refrigerant is 1/99 to 50/5
0, and more preferably 1/99 to 30/70. Even in such a mixing ratio, excellent lubricity is exhibited. Further, a composition comprising such a mixture of a lubricating oil and a CFC refrigerant is at least -50C to + 15C, and furthermore -50C.
At a temperature of up to + 30 ° C., especially -60 ° C. to + 50 ° C., a phase which is stably compatible is formed, and exhibits particularly excellent lubricating performance of a CFC compressor such as HFC-134a.

The lubricating oil of the present invention has a pour point of -20 ° C. or less,
Preferably, it is -20 to -80C. The lubricating oil for CFC compressor of the present invention is a CFC compressor using CFC refrigerant, which has extremely excellent lubricity, load resistance,
It exhibits abrasion resistance, and also has excellent CFC stability and moisture absorption resistance. As the chlorofluorocarbon refrigerant used together with the chlorofluorocarbon compressor lubricating oil of the present invention, chlorofluorocarbon refrigerants such as CFC-11 and CFC-12 having chlorine and fluorine as components can be used, and hydrogen is further added as a component. It can be preferably used for a hydrogen-containing Freon refrigerant such as HCFC-22. Particularly preferably, it is applicable to a refrigerant which is a hydrofluorocarbon containing no chlorine. Examples of such a refrigerant include 1,1,
1,2-tetrafluoroethane (HFC-134a),
1,1,2,2-tetrafluoroethane (HFC-13
4), 1,1-difluoroethane (HFC-152
a), difluoromethane (HFC-32), and pentafluoroethane (HFC-125).
Further, the lubricating oil and the composition of the present invention, a refrigerator, a refrigerator,
It can be preferably used as a lubricant for various compressors such as a reciprocating type, a rotary type, a centrifugal type and a swash plate type used for an air conditioner for a car, a room, or an industrial use.

[0024]

EXAMPLES Hereinafter, the contents of the present invention will be described more specifically with reference to examples and comparative examples. Lubricants A1~9 shown in Examples 1 to 15 and Comparative Examples 1 to 8 Table 1, the B1~7 shown in A13~15 and Table 2, the alcohol corresponding to _{R 1} in the general formula (I), respectively, below Was synthesized by polymerizing propylene oxide and ethylene oxide according to the method described above, and purified to produce a prototype. Further, lubricating oils A10 to A12 are lubricating oils obtained by mixing the two types of lubricating oils prototyped as described above in the proportions shown in Table 1, and B8 shown in Table 2 is a commercially available polyoxyalkylene monoalkyl ether compound. (Sanyo Chemical Co., Ltd.)
Newpole 50HB-2000). Lubricating oils A1 to 15 are examples of the present invention, and lubricating oils B1 to B8 are comparative examples. The performance of each of the lubricating oils of these Examples and Comparative Examples was evaluated.

Method for Producing Lubricating Oil The lubricating oil A1 shown in Table 1 was produced as follows. That is, methanol 116 was added to a 5-liter autoclave.
g and 12 g of sodium methylate, and after sufficiently purging with nitrogen gas, at a temperature of 100 to 120 ° C. and a pressure of 1 to 7 kg.
/ Cm propylene oxide 3,128 under conditions of ² G
g was gradually added dropwise to carry out a reaction for 14 hours. After aging for 2 hours, unreacted propylene oxide was removed by blowing nitrogen gas. Next, 695 g of ethylene oxide is added over 1 hour under the conditions of a temperature of 100 to 140 ° C. and a pressure of 1 to 7 kg / cm ² G, and after aging for 2 hours under the same conditions, nitrogen gas is blown into unreacted ethylene oxide. Removed. After cooling, the mixture was transferred to a 5-liter eggplant-shaped flask, neutralized with an acid, and dehydrated by blowing nitrogen gas at 120 ° C. under a vacuum of 20 mmHg or less for 2 hours. After cooling, the salt was removed with a filter to obtain 3,920 g of lubricating oil A1 (polyoxypropyleneoxyethylene monomethyl ether). In addition, Z / (y + z) of the obtained lubricating oil A1 is N
The value determined by MR is 0.20, which is almost equal to the value based on the raw material input amounts of propylene oxide and ethylene oxide (Z / (y + z) = 0.23).

The random copolymer lubricating oil B4 was produced as follows. As in the preparation of the block copolymer A1 described above, 116 g of methanol and 12 g of sodium methylate were placed in a 5-liter autoclave, and sufficiently purged with nitrogen gas. Then, instead of propylene oxide of A1, 3200 g of propylene oxide and ethylene were used. Except for using a mixed solution of 620 g of oxide, 3,845 g of a random copolymer of B4 was obtained in the same manner as in the production of A1.

Prototyping oils except A10-12 and B8 other than the canned lubricating oils A1 and B4 were also produced by controlling the alkanol, its amount used, the amount of each oxide, and the dropping order. The physical properties and performance of each lubricating oil shown as Examples and Comparative Examples were measured for average molecular weight, kinematic viscosity, pour point, compatibility with Freon refrigerant, and lubricity. Also, the z / (y + z) ratio indicates that the product yield is almost 100%.
%, Which is almost the same as the measurement result by NMR, it was calculated based on the input amounts of the propylene oxide and ethylene oxide raw materials used in the reaction. The results are shown in Tables 1 and 2. The outline of the test method used for the measurement is as follows.

[0028]

[Table 1]

[0029]

[Table 2]

Average molecular weight The weight average molecular weight was measured by GPC (gel permeation chromatography). Kinematic viscosity was measured based on JISK 2283.

The pour point was measured according to JIS K2269. Compatibility Each lubricating oil 0.6g and the refrigerant of the refrigerant (HFC-134a) 2.4g
Was sealed in a glass tube and then cooled at 1 ° C. per minute to measure the temperature at which two-layer separation occurs at low temperature, that is, the low-temperature two-layer separation temperature. On the high-temperature side, a high-temperature two-layer separation temperature at which the temperature was raised from room temperature at 1 ° C. per minute to cause two-layer separation was measured.

In accordance with ASTM D-3233-7, Falex baking load was set to HFC-134a, HFC
It measured under the blowing atmosphere of -32 (70 ml / min). The test pins were made of FC-20 and the test blocks were made of AISI 1137.

Using a Falex tester, a load of 30
0 Lbf, rotation speed 290 rpm, temperature (40 ° C., initial temperature), test pin (FC-20), test block (A
ISI1137), an abrasion test was performed for 1 hour in an atmosphere of HFC-134a blowing (70 ml / min), and the amount of abrasion of the pin was measured.

[0034] Compressors for car air conditioners (Zexe
The test was conducted under the following conditions.
Of the main bearing of the compressor after continuous operation for 00 hours)
Bell and metals in lubricating oil after test (iron, aluminum
Was measured. Refrigerant HFC-134a amount 1 kg Lubricating oil amount 0.12 kg Rotational speed 500 rpm Discharge pressure 19 kg / cm²  Suction pressure 1.7 kg / cm²  Discharge gas temperature 130 ℃

The evaluation results are shown in Tables 1 and 2. The lubricating oil comprising the block copolymer of polyoxypropyleneoxyethylene glycol monoalkyl ether of the present invention has excellent compatibility with the refrigerant, and exhibits much better lubricity than the random copolymer. Incidentally, the Falex baking load is as high as 1300 to 1600 Lbf, the wear amount is 5 mg or less, and no wear is recognized even in the compressor test.

On the other hand, B1 of Comparative Example has low lubricity because oxyethylene is not contained in the polymer. B4, B5, B6
And B8 are random polymers, and high lubricity has not been obtained. Although B2 and B3 are block copolymers, they have a structure in which a hydroxyl group is attached to oxypropylene, and the methyl group of oxypropylene hinders the formation of a strong adsorption film due to the hydroxyl group and the like, so that high lubricity is obtained. Absent. B7 has good lubricity because it is a block copolymer having the same arrangement as that of the present invention, but has a problem that the pour point is high because z / (y + z) is as large as 0.6.

Examples 16 and 17 The performance of a mixture of a compound of the general formula (I ') and a compound of the general formula (II) was evaluated. As the compound of the general formula (I ′), a polyoxyalkylene monoalkyl ether of A1 is used, and as the compound of the general formula (II), CH ₃ —O— (R ₄ O) m— (CH ₂ CH) is used.
Using ₂ O) polyoxyalkylene alkyl ethers represented by n-CH ₃ (abbreviated as C1). In C1, (R ₄ O) is an oxypropylene group, and m / n is 8 /
2, the molecular weight is about 1000, and the viscosity is 10 cSt (10
0 ° C). The mixture obtained by mixing A1 and C1 at the ratios shown in Table 3 was tested for lubricity, compatibility, hygroscopicity, and compressor test. The results are shown in Table 3.

The lubricity, compatibility, and compressor tests were performed by the methods described above, and the hygroscopic test was performed by the following method. Collect 60 g of the test oil in a hygroscopic 100 ml beaker,
After leaving still for 7 days in a room at 80 ° C. and a humidity of 80%, the water concentration of the test oil was measured. As shown in Table 3, when C1 was used alone, the hygroscopicity was low and excellent, but the abrasion resistance was insufficient.
It can be seen that the mixture obtained by mixing No. 1 (A16 and A17) exhibits abrasion resistance close to A1, has low hygroscopicity, and has good characteristics as a refrigerating machine oil.

[0039]

[Table 3]

As described above, the specific block copolymer of the present invention has extremely high lubricity and is mutually soluble with a chlorine-containing Freon refrigerant, so that HFC-134a, HFC-HFC -32, HFC-125
It can be said that the lubricant is a lubricating oil that compensates for a decrease in lubricity due to the change of the refrigerant when the refrigerant is changed to a hydrogen-containing Freon refrigerant.

[0041]

The lubricating oil of the present invention is HFC134a, HFC134a
FC134, HFC152a, HFC32 and HFC1
It is a lubricating oil that has excellent compatibility in a wide temperature range, has low hygroscopicity, and has extremely high lubricity even under conditions of a hydrogen-containing Freon refrigerant such as 25, and is suitable for lubricating oil for refrigerators. Further, it exhibits excellent performance even under the conditions of conventional CFC-12 and CFC-22.

 ──────────────────────────────────────────────────続 き Continued on the front page (72) Inventor Junro Yokoo 2 Takara-cho, Kanagawa-ku, Yokohama-shi, Kanagawa Nissan Motor Co., Ltd. (72) Inventor Keie Arakawa 2 Takara-cho, Kanagawa-ku, Yokohama-shi, Kanagawa In-house (56) References JP-A 4-55498 (JP, U)

Claims (4)

(57) [Claims] 1. A lubricating oil for a CFC compressor comprising as a main component at least one compound represented by the following general formula (I). R ₁ -[-O- (R ₂ O) _y- (CH ₂ CH ₂ O) _z -H] _x (I) (In the formula (I), R ₁ has 1 to 8 carbon atoms having one hydroxyl group. R ₂ represents a hydrocarbon residue of an alcohol;
-4 branched alkylene groups, x is an integer of 1, y and z
Each independently represents an integer. The R ₂ O unit and the CH ₂ CH ₂ O unit are block-polymerized in the arrangement order of the formula (I), and satisfy 0 <z / (y + z) ≦ 0.4. ) 2. Lubricating oil for a CFC compressor mainly comprising a mixture of at least one compound represented by the following general formula (I ′) and at least one compound represented by the following general formula (II): oil. R ₁ -[— O— (R ₂ O) _y — (CH ₂ CH ₂ O) _z —H] _x (I ′) (In the formula (I ′), R ₁ represents a carbon number having ₁ to 4 hydroxyl groups. A hydrocarbon residue of an alcohol of 1-8, R ₂ represents a branched alkylene group having 3-4 carbon atoms, x represents an integer of 1-4, and y and z each independently represent an integer.
_{The 2} O unit and the CH ₂ CH ₂ O unit are represented by the formula (I ′)
And O <z / (y + z)
Satisfies ≦ 0.5. ) R ₃ - _{[- O- (R 4 O) m} - (CH 2 CH 2 O) n -R 5 ] in _L (II) (Formula (II), the number of carbon atoms _{R 3} is having 1-4 hydroxyl groups A hydrocarbon residue of an alcohol having 1-8, R ₄ is a branched alkylene group having 3-4 carbon atoms, R ₅ is an alkyl group having 1-8 carbon atoms, 1 is an integer of 1-4, m and n are And each independently represents an integer, and an R ₄ O unit and CH ₂
The CH ₂ O unit undergoes block polymerization, and 0 <n / (m +
n) ≦ 0.5 is satisfied. ) 3. At least one compound represented by the general formula (I) according to claim 1 or at least one compound represented by the general formula (I ′) according to claim 2 and the general compound according to claim 2 A composition for a CFC compressor, comprising a mixture of a CFC compressor lubricating oil comprising a mixture of at least one compound represented by the formula (II) as a main component and at least one CFC refrigerant. 4. At least one compound represented by the general formula (I) according to claim 1 or at least one compound represented by the general formula (I ′) according to claim 2 and the general compound according to claim 2 A method for lubricating a CFC compressor, wherein a CFC compressor lubricating oil mainly comprising a mixture with at least one compound represented by the formula (II) is used for a CFC compressor using at least one CFC refrigerant.