HK1025990B

HK1025990B - Lubricating oil composition for refrigerators and method for lubrication with the composition

Info

Publication number: HK1025990B
Application number: HK00105131.9A
Authority: HK
Inventors: 永尾智; 半田丰和
Original assignee: 出光兴产株式会社
Priority date: 1996-11-27
Filing date: 1997-11-17
Publication date: 2003-09-05

Description

Lubricating oil composition for refrigerator and lubricating method using the same

Technical Field

The present invention relates to a lubricating oil composition for a refrigerator and a lubricating method, and more particularly, to a lubricating oil composition for a refrigerator using a refrigerant containing hydrocarbons having 1 to 8 carbon atoms as a main component, and a lubricating method using the same.

Background

For example, in a compression refrigeration cycle of a compression type refrigerator including a compressor, a condenser, an expansion valve, and an evaporator, the refrigerator is generally designed such that a mixed liquid of a refrigerant and a base oil circulates in the closed system. In such a compression-type refrigerator, dichlorodifluoromethane (R-12) and chlorodifluoromethane (R-22) have been widely used as refrigerants, and various mineral oils and synthetic oils have been used as base oils. However, since chlorofluorocarbons such as R-12 and R-22 are considered to cause environmental pollution by destroying the ozone layer existing in the stratosphere, their use has recently been restricted in the world. Therefore, hydrogen-containing fluorocarbons (フロン) such as hydrofluorocarbons and hydrochlorofluorocarbons have attracted attention as novel refrigerants. Such hydrogen-containing fluorocarbons, particularly hydrofluorocarbons represented by 1, 1, 1, 2-tetrafluoroethane (R-134a), do not destroy the ozone layer, but their life in the atmosphere is long, and there is a concern about their effect on global warming, and in recent years, various hydrocarbons, particularly hydrocarbons having 1 to 8 carbon atoms, of natural refrigerants which do not have such problems have been studied.

However, in the case of using a base oil composed of a mineral oil and an alkylbenzene, which have been conventionally and conventionally used, in a compression refrigerator using such a hydrocarbon as a refrigerant, the refrigerant is completely dissolved in the base oil, and the viscosity of the base oil is lowered. This causes poor lubrication performance and wear resistance, and the sealing material used in the refrigerant cycle system deteriorates to deteriorate the sealing performance of the system, which may lead to a fear that the refrigerant cannot be used stably for a long period of time. In particular, when a capillary tube is used as the expansion valve, the sealing property tends to be further deteriorated.

The present invention has been made in view of the above circumstances, and an object thereof is to provide a lubricating oil composition for a refrigerating machine, which has excellent performance as a lubricating oil for a refrigeration cycle, which is a compression type refrigerating machine using a refrigerant mainly containing a hydrocarbon, can reduce wear of the machine, can be stably used for a long period of time, and can improve refrigeration efficiency. It is another object of the present invention to provide a lubricating method using the composition.

Summary of The Invention

The present inventors have made extensive studies and as a result, have found that the object of the present invention can be effectively achieved by using a hydrocarbon compound having specific properties or composition as a base oil, and have completed the present invention.

Namely, the present invention is:

(1) a lubricating oil composition for a refrigerator, characterized by comprising (A) a refrigerant containing a hydrocarbon of 1 to 8 carbon atoms as a main component and (B) a lubricant having a non-aromatic unsaturation degree of less than 10% and a kinematic viscosity at 100 ℃ of more than 5mm²Hydrocarbon base oil/s; or

(2) A refrigerating machine oil composition characterized by comprising (A) a refrigerant mainly comprising a hydrocarbon having 1 to 8 carbon atoms and (C) a refrigerant represented by the following general formula (I) and satisfying one of the following formulas (II), (III) and (IV) and having a kinematic viscosity at 100 ℃ of 5 to 200mm²Polyalkylene glycol derivatives per second as the main component of the base oil.

R¹O-(PO)_a-(EO)_b-R²... (I) (in the formula, R¹And R²Each represents a hydrogen atom, an alkyl group having 1 to 10 carbon atoms, or an acyl group having 2 to 10 carbon atoms, and may be the same or different from each other. In addition, PO represents an oxypropylene group, EO represents an oxyethylene group, and a and b are each 0 or a positive number, and satisfy 2. ltoreq. a + b. ltoreq.80).

①R¹And R²All being hydrogen atoms

1≤10X≤8 ...(II)

(wherein X represents the mole fraction of PO in the molecule, and X is a/(a + b)).

②R¹And R²Where either is hydrogen

1≤10X+Y/4≤9 ...(III)

(wherein X is as defined above and Y represents R¹And R²The sum of the number of carbon atoms) of (c).

③R¹And R²All are not hydrogen

3≤10X+Y≤10 ...(IV)

(wherein X, Y is as defined above).

In addition, the present invention is:

(3) a method for lubricating a compression refrigerator using the refrigerator oil composition according to any one of (1) and (2).

Brief description of the drawings

Fig. 1 is a flow diagram of a compression refrigeration cycle of "compressor-condenser-expansion valve-evaporator". In fig. 1, reference numeral 1 denotes a compressor, reference numeral 2 denotes a condenser, reference numeral 3 denotes an expansion valve, and reference numeral 4 denotes an evaporator.

Best Mode for Carrying Out The Invention

The following describes embodiments of the present invention.

The first invention of this application is a lubricating oil composition for a refrigerator, characterized by comprising (A) a refrigerant containing a hydrocarbon having 1 to 8 carbon atoms as a main component and (B) a lubricant having a non-aromatic unsaturation degree of less than 10% and a kinematic viscosity at 100 ℃ of more than 5mm²A base oil containing a hydrocarbon compound per second as a main component.

The carbon number of the hydrocarbon as the main component of the refrigerant (A) of the present invention is 1 to 8, preferably 1 to 5, more preferably 3 to 5. Hydrocarbons having more than 9 carbon atoms have too high a boiling point and thus have deteriorated performance as a refrigerant. Examples of the hydrocarbon of the present invention include methane, ethane, ethylene, propane, cyclopropane, propylene, n-butane, isobutane, n-pentane and isopentane. These hydrocarbons may be used singly or in combination. The refrigerant of the present invention comprises the above hydrocarbon as a main component, and is usually 70% by weight or more, preferably 90% by weight or more. That is, in the present invention, 70% by weight or more, preferably 90% by weight or more of the above-mentioned hydrocarbon and 30% by weight or less, preferably 10% by weight or less of another refrigerant, for example, hydrofluorocarbons such as R-134a, ethers, CO, etc., can be used₂And the like as a mixture of conventional refrigerants. When the amount of the other refrigerant exceeds 30% by weight, it is impossible to reduce the influence on the global warming.

The non-aromatic unsaturation degree of the hydrocarbon compound as the main component of the base oil (B) in the present invention means a ratio of carbon-carbon unsaturated bonds not derived from aromatic sites among all carbon-carbon bonds in the hydrocarbon molecule, and can be calculated by the following formula. The various values used in the calculations were determined by NMR.

Non-aromatic unsaturation degree (%) × 100 (number of unsaturated bonds not derived from aromatic group in molecule/number of all carbon-carbon bonds in molecule)

In the present invention, this value is less than 10%, preferably less than 5%, more preferably less than 1%, and particularly desirably less than 0.1%. When the concentration exceeds 10%, sludge is generated to clog the capillary.

In addition, the base oil (B) of the present invention has a kinematic viscosity at 100 ℃ of more than 5mm²S, preferably greater than 10mm²A specific preferred thickness is 20 to 500mm²And s. When the kinematic viscosity is less than 5mm²The base oil/s reduces the sealing performance of the refrigerator and the lubricating performance thereof.

Various oils may be used as the base oil, preferably highly purified mineral oils, alkylbenzenes, alkylnaphthalenes, or poly-alpha-olefins, the non-aromatic unsaturation and kinematic viscosity being desirably within specific ranges.

Specific examples of highly purified mineral oils include: a refined oil obtained by subjecting a paraffinic crude oil, an intermediate base crude oil or a naphthalene base crude oil to atmospheric distillation or subjecting an atmospheric distillation residue to vacuum distillation and refining the obtained distillate oil by a conventional method; or a highly dewaxed oil obtained by further performing a deep dewaxing treatment after refining and a hydrotreated oil obtained by further performing a hydrotreating. The purification method in this case includes: (a) hydrotreating; (b) dewaxing treatment (solvent dewaxing or hydrodewaxing); (c) solvent extraction treatment; (d) alkali distillation or sulfuric acid washing treatment is carried out; or (e) treatment of gypsum powder. These purification methods may be used alone or in combination as appropriate. In addition, a method of repeatedly performing the same process in several stages is also effective. For example, there are known a method of hydrotreating a distillate oil; ② a method for treating distillate oil by adding alkali and distilling or washing with sulfuric acid after hydrotreating; ③ carrying out dewaxing treatment after carrying out hydrotreating on the distillate oil; fourthly, the distillate oil is subjected to hydrogenation treatment after solvent extraction treatment; second or third grade distillate oil hydrogenation treatment, or alkali distillation or sulfuric acid washing treatment; and sixthly, dewaxing again to generate deep dewaxed oil after the treatment according to the first to the fifth steps. Examples of the dewaxing treatment include solvent dewaxing under severe conditions, and contact dewaxing with a zeolite catalyst. Among the above-mentioned methods, highly refined mineral oils used in the present invention are suitable for the deep dewaxed oil from the viewpoint of low-temperature fluidity, no wax precipitation at low temperatures, and the like.

The highly refined mineral oil may be used singly or in combination of two or more of the above. When two or more kinds are mixed, the kinematic viscosity of each highly refined mineral oil is preferably within the above-mentioned specific range, however, the kinematic viscosity of the highly refined mineral oil after mixing may be used within the above-mentioned specific range.

Further, as the alkylbenzene, any one of alkylbenzenes used in conventional refrigerator oils and the like can be used, but in the present invention, an alkylbenzene having a higher viscosity than that of an alkylbenzene used in the conventional art is used.

Examples of such high-viscosity alkylbenzenes include monoalkylbenzenes, dialkylbenzenes, trialkylbenzenes, and the like, alkylbenzenes in which 1 or 2 or more alkyl groups are substituted, and alkylbenzenes in which the total number of carbon atoms in each alkyl group is greater than 20. Among them, alkylbenzenes having 2 or more alkyl groups and alkylbenzenes in which the total number of carbon atoms in each alkyl group is more than 20 are preferable from the viewpoint of thermal stability.

Further, the alkylbenzene may be used singly or in combination of two or more of the above. When 2 or more alkylbenzenes are mixed, the kinematic viscosity of each alkylbenzene is preferably within the above-mentioned specific range, but the kinematic viscosity of the alkylbenzene after mixing may be within the above-mentioned specific range.

Further, as the alkylnaphthalene, alkylnaphthalenes having 2 or 3 substituted alkyl groups on the naphthalene ring, particularly alkylnaphthalenes having a total number of carbon atoms of the alkyl group of more than 20, can be preferably used from the viewpoint of thermal stability.

The alkylnaphthalene may be used singly or in combination of two or more kinds thereof. When 2 or more alkylnaphthalenes are mixed, the kinematic viscosity of each alkylnaphthalene is preferably within the above-specified range, but if the kinematic viscosity of the alkylnaphthalene after mixing is within the above-specified range, the alkylnaphthalene may be used.

Further, as the polyalphaolefin, an alpha-olefin polymer having 8 to 18 carbon atoms is preferable from the viewpoint of thermal stability, sealing property of a refrigerator, lubricating property and the like, and particularly, a 1-dodecene, 1-decene or 1-octene polymer is preferable. In the present invention, it is particularly preferable to use a hydrotreated polyalphaolefin thereof from the viewpoint of thermal stability.

The polyalphaolefin may be used singly or in combination of two or more kinds thereof. When two or more kinds are mixed and used, the kinematic viscosity of each polyalphaolefin is desirably within the above-specified range, but if the kinematic viscosity of the polyalphaolefin after mixing is within the above-specified range, it may be used.

Among the highly refined mineral oils, alkylbenzenes, alkylnaphthalenes, and polyalphaolefins, the base oil of the present invention may be used alone or in combination of two or more. When 2 or more kinds are mixed, the kinematic viscosity of each component is desirably within the above-specified range, but if the kinematic viscosity of the base oil finally obtained by mixing is within the above-specified range, it may be used.

In the present invention, highly refined mineral oils among the above base oils are particularly preferable in view of price, the degree of unsaturation being controllable by the degree of refining, and the like.

In the first invention of the present application, the ratio of the refrigerant of component (a) to the base oil of component (B), i.e., the (a)/component (B) weight ratio, is preferably 99/1 to 10/90, and more preferably 95/5 to 30/70. (A) When the amount of the component is less than 10/90, the refrigerating ability may be lowered, and when it is more than 99/1, the lubricating performance may be lowered.

Next, the second invention of the present application is a lubricating oil composition for a refrigerator, characterized by comprising (A) a refrigerant mainly comprising a hydrocarbon having 1 to 8 carbon atoms and (C) a kinematic viscosity at 100 ℃ of more than 5mm²A base oil comprising a polyalkylene glycol derivative in s.

Here, the component (a) refrigerant of the present invention has been described in the first invention of the present application.

In the present invention, as the base oil of the component (C), a polyalkylene glycol derivative represented by the following general formula (I) and satisfying any one of the following formulae (II), (III) and (IV) can be used.

R¹O-(PO)_a-(EO)_b-R² ...(I)

(in the formula, R¹And R²Each represents a hydrogen atom, an alkyl group having 1 to 10 carbon atoms, or an acyl group having 2 to 10 carbon atoms, and they may be the same or different from each other. PO represents an oxypropylene group and EO represents an oxyethylene group. a and b are each 0 or a positive number, and satisfy 2. ltoreq. a + b. ltoreq.80).

①R¹And R²All being hydrogen atoms

1≤10X≤8 ...(II)

②R¹And R²Where one of them is a hydrogen atom

1≤10X+Y/4≤9 ...(III)

③R¹And R²All are not hydrogen atoms

3≤10X+Y≤10 ...(IV)

(wherein X, Y is as defined above).

R in the above general formula (I)¹、R²The number of carbon atoms of the alkyl group(s) is 1 to 10, preferably 1 to 6. When the number of carbon atoms of the alkyl group exceeds 10, the compatibility of the base oil with the refrigerant hydrocarbon is significantly improved, and the hydrocarbon is completely dissolved at an arbitrary ratio. The alkyl group may be linear, branched or cyclic. Specific examples of the alkyl group include a methyl group, an ethyl group, an n-propyl group, an isopropyl group, various butyl groups, various pentyl groups, various hexyl groups, various heptyl groups, various octyl groups, various nonyl groups, various decyl groups, a cyclopentyl group, and a cyclohexyl group.

In addition, R¹、R²The number of carbon atoms of the acyl group is 2 to 10, preferably 2 to 6. When the number of carbon atoms of the acyl group exceeds 10, the base oil is more compatible with the refrigerant hydrocarbon, and the hydrocarbon can be completely dissolved in an arbitrary ratio. The alkyl moiety of the acyl group may be linear, branched or cyclic. Specific examples of the alkyl moiety of the acyl group include various groups having 1 to 9 carbon atoms as exemplified above for the alkyl group.

The repeating units PO and EO in the general formula (I) may be a block or an irregular unit.

The base oil of the second invention of the present application must satisfy any of the above-mentioned relational expressions (II), (III) and (IV). If the composition does not satisfy the formula (II) (10 X.ltoreq.8), (III) (10X + Y/4. ltoreq.9), or (IV) (10X + Y. ltoreq.10), the base oil is not well dissolved in the refrigerant hydrocarbon. Further, when the components do not satisfy (1. ltoreq.10X) of the formula (II), (1. ltoreq.10X + Y/4) of the formula (III), and (3. ltoreq.10X + Y) of the formula (IV), the compatibility of the base oil with the refrigerant hydrocarbon is lowered, and phase separation occurs. In view of compatibility between the base oil and the refrigerant hydrocarbon, it is preferable that any one of the following formulas (II) ', (III) ' and (IV) ' is satisfied.

①R¹And R²All being hydrogen atoms

4≤10X≤7 ...(II)′

②R¹And R²In the case where any one of them is a hydrogen atom

4≤10X+Y/4≤8 ...(III)′

③R¹And R²All are not hydrogen atoms

5≤10X+Y≤9 ...(IV)′

The base oil of component (C) of the present invention has a kinematic viscosity at 100 ℃ of 5 to 200mm²(ii) s, preferably 9 to 100mm²And s. When the kinematic viscosity is less than 5mm²At/s, coldThe sealing performance of the freezing cycle part of the freezer is lowered and the lubricating performance is lowered, so that it is not preferable. On the contrary, more than 200mm²At a time of/s, the viscous resistance at low temperature increases, the torque increases, and the refrigerator is difficult to start.

The base oil of the present invention may be used alone or in combination of two or more kinds of the polyalkylene glycol derivatives.

In the second invention of the present application, the ratio of the refrigerant (A) to the base oil (C) is 99/1 to 10/90, preferably 95/5 to 30/70 in terms of the weight ratio of component (A)/component (C). When the amount of the component (a) is less than 10/90, the freezing capacity may be lowered, and when it exceeds 99/1, the lubricating performance may be lowered.

In the lubricating oil composition for a refrigerator according to the first or second aspect of the present invention, if necessary, various known additives, for example, high pressure resistant additives such as phosphate esters such as tricresyl phosphate (TCP) and phosphite esters such as trisnonylphenyl phosphite; phenolic and aminic antioxidants; stabilizers such as phenyl glycidyl ether, cyclohexene oxide, epoxidized soybean oil, and the like; copper deactivators such as benzotriazole and its derivatives; defoaming agents such as silicone oil and fluorinated silicone oil. Further, as necessary, a load-bearing additive, a chlorine scavenger, a purification dispersant, a viscosity index improver, an oiliness agent, a rust preventive, a preservative, a pour point depressant, and the like may be added. In general, these additives may be present in the compositions of the invention in an amount of from 0.5 to 10% by weight.

The third invention of the present application is a method for lubricating a compression refrigerator, characterized by using the lubricating oil composition for a refrigerator of the first or second invention.

The lubricating oil composition for a refrigerator according to the first or second aspect of the present invention can be used for various refrigerators. In particular, the present invention is applicable to a compression refrigeration cycle of a compression refrigerator, and is more applicable to a normal compression refrigeration cycle including a compressor, a condenser, an expansion valve, and an evaporator shown in fig. 1.

The present invention will be described more specifically with reference to the following examples, but the present invention is not limited to these examples. Examples 1 to 7 and proportions 1 and 2

(1) Lubricating oil composition for refrigerator

A refrigerant (70 wt.%) consisting of a propane-isobutane mixture at a molar ratio of 1: 1 was mixed with a base oil (30 wt.%) having the properties shown in Table 1 to prepare lubricating oil compositions for refrigerators of examples 1 to 7 and comparative examples 1 and 2. Using the lubricating oil composition for a refrigerator, an actual machine test was carried out in the following manner to evaluate the performance. The results are shown in Table 1.

(2) Refrigeration cycle mode of compressor

As the refrigerator, a compressor refrigeration cycle constituted by a general "compressor-condenser-expansion valve-evaporator" is used. Among them, a capillary expansion valve can be used as the expansion valve.

(3) Test on a real machine

The above-prepared lubricating oil composition for a refrigerator was filled in the refrigerator having an output of 100W, and a freezing test was continuously conducted for 1 year under the following conditions.

(operating conditions)

The inlet air temperature: 0 deg.C

Discharge temperature: 100 deg.C

Condenser outlet temperature: 10 deg.C

(evaluation method)

And stopping the machine when the running state is abnormal, observing each part, and checking the reason.

TABLE 1

	Base oil	Kinematic viscosity (mm)²/s)(100℃)	Degree of unsaturation (%)	Status of state
	Base oil	Kinematic viscosity (mm)²/s)(100℃)	Degree of unsaturation (%)	Status of state	Example 1	Mineral oil 1^*1	22	0.1＞	No abnormality
Example 2	Mineral oil 2^*2	10	0.1＞	No abnormality	Example 1	Mineral oil 1^*1	22	0.1＞	No abnormality
Example 2	Mineral oil 2^*2	10	0.1＞	No abnormality	Example 3	Mineral oil 3^*3	5	0.1＞	No abnormality
Example 4	Mineral oil 4^*4	25	7	Less slurryQuantity generation	Example 3	Mineral oil 3^*3	5	0.1＞	No abnormality
Example 4	Mineral oil 4^*4	25	7	Less slurryQuantity generation	Example 5	Alkyl benzene^*5	15	0.1＞	No abnormality
Example 6	Alkyl benzene^*6	21	0.1＞	No abnormality	Example 5	Alkyl benzene^*5	15	0.1＞	No abnormality
Example 6	Alkyl benzene^*6	21	0.1＞	No abnormality	Example 7	Poly alpha-olefins^*7	20	0.1＞	No abnormality
Comparative example 1	Mineral oil 5^*8	3	0.1＞	Is subjected to sintering	Example 7	Poly alpha-olefins^*7	20	0.1＞	No abnormality
Comparative example 1	Mineral oil 5^*8	3	0.1＞	Is subjected to sintering	Comparative example 2	Mineral oil 6^*9	25	13	Capillary tube blockage

^*1: base oils obtained by deep dewaxing and hydrotreating of paraffinic mineral oils;^*2: base oils obtained by deep dewaxing and hydrotreating of paraffinic mineral oils;^*3: base oils obtained by deep dewaxing and hydrotreating of paraffinic mineral oils;^*4: a base oil solvent-refined from a paraffinic mineral oil;^*5: a base oil obtained by hydrotreating alkylbenzene and treating gypsum powder;^*6: a base oil obtained by hydrotreating an alkylnaphthalene and treating a landplaster;^*7: a hydrotreated 1-decene polymer;^*8: base oils obtained by deep dewaxing and hydrotreating of paraffinic mineral oils;^*9: a naphthalene based mineral oil solvent refined base oil. Examples 8 to 12 and comparative examples 3 to 5]

Polyalkylene glycol derivatives (random copolymers of PO and EO) having the properties shown in Table 2 were produced, and the amounts of dissolved n-pentane were measured by the following methods. The results are shown in Table 3.

< amount of dissolved n-pentane (20 ℃ C.) >

20g of the sample oil was put into a glass beaker, and a small amount of n-pentane was added successively while stirring, and the point at which turbidity occurred was defined as an end point. The amount of dissolution was calculated as follows.

TABLE 2

	R¹	R²	a	b	Kinematic viscosity (mm)²/s)(100℃)
	R¹	R²	a	b	Kinematic viscosity (mm)²/s)(100℃)	Example 8	Hydrogen atom	Hydrogen atom	10.0	10.0	11.0
Example 9	Hydrogen atom	Hydrogen atom	16.0	7.0	13.0	Example 8	Hydrogen atom	Hydrogen atom	10.0	10.0	11.0
Example 9	Hydrogen atom	Hydrogen atom	16.0	7.0	13.0	Example 10	Methyl radical	Hydrogen atom	14.0	6.0	11.0
Example 11	Methyl radical	Methyl radical	18.0	8.0	16.2	Example 10	Methyl radical	Hydrogen atom	14.0	6.0	11.0
Example 11	Methyl radical	Methyl radical	18.0	8.0	16.2	Example 12	Methyl radical	Methyl radical	22.0	22.0	30.5
Comparative example 3	Hydrogen atom	Hydrogen atom	17.0	0	10.5	Example 12	Methyl radical	Methyl radical	22.0	22.0	30.5
Comparative example 3	Hydrogen atom	Hydrogen atom	17.0	0	10.5	Comparative example 4	Hydrogen atom	Hydrogen atom	20.0	0	12.6
Comparative example 5	Methyl radical	Methyl radical	26.0	0	15.3	Comparative example 4	Hydrogen atom	Hydrogen atom	20.0	0	12.6

TABLE 3

	X	Y	Adopt the formula	Value of the formula	N-pentane dissolved amount
	X	Y	Adopt the formula	Value of the formula	N-pentane dissolved amount	Example 8	0.50	0	II	5.0	11.0
Example 9	0.70	0	II	7.0	13.3	Example 8	0.50	0	II	5.0	11.0
Example 9	0.70	0	II	7.0	13.3	Example 10	0.70	1	III	7.25	11.0
Example 11	0.69	2	IV	8.9	16.2	Example 10	0.70	1	III	7.25	11.0
Example 11	0.69	2	IV	8.9	16.2	Example 12	0.50	2	IV	7.0	30.5
Comparative example 3	1.00	0	II	10.0	10.5	Example 12	0.50	2	IV	7.0	30.5
Comparative example 3	1.00	0	II	10.0	10.5	Comparative example 4	1.00	1	III	10.25	12.6
Comparative example 5	1.00	2	IV	12.0	15.3	Comparative example 4	1.00	1	III	10.25	12.6

Application in industry

The invention provides a lubricating oil composition for a refrigerator and a lubricating method using the same, which can effectively lubricate a compression-type refrigeration cycle using a refrigerant containing a hydrocarbon having 1-8 carbon atoms as a main component, and as a result, reduce the abrasion in the compression-type refrigerator, improve the sealing performance, increase the stability of long-term operation, and improve the refrigeration efficiency.

Claims

1. A lubricating oil composition for a refrigerator, characterized by comprising (A) a refrigerant containing a hydrocarbon having 1 to 8 carbon atoms as a main component and (B) a lubricating oil composition containing a non-aromatic unsaturated compound having a degree of unsaturation of less than 10% and a kinematic viscosity at 100 ℃ of more than 5mm²And/s a base oil comprising a hydrocarbon compound selected from the group consisting of alkylbenzenes and poly-alpha-olefins, wherein the weight ratio of the refrigerant of component (A) to the base oil of component (B) is 99/1 to 10/90.

2. The lubricating oil composition for a refrigerator is characterized by containing (A) a lubricant having 1 to 8 carbon atomsA refrigerant containing a hydrocarbon as a main component, and (C) a refrigerant represented by the following general formula (I), satisfying one of the following formulas (II), (III) and (IV), and having a kinematic viscosity at 100 ℃ of 5 to 200mm²A base oil containing a polyalkylene glycol derivative as a main component,

R¹O-(PO)_a-(EO)_b-R²... (I) wherein R is¹And R²Each represents a hydrogen atom, an alkyl group having 1 to 10 carbon atoms or an acyl group having 2 to 10 carbon atoms, and may be the same or different from each other, PO represents an oxypropylene group, EO represents an oxyethylene group, a and b are 0 or a positive number, and satisfy 2. ltoreq. a + b. ltoreq.80,

①R¹and R²All being hydrogen atoms

(II) 1 ≦ 10X ≦ 8. (II) wherein X represents a mole fraction of PO in a molecule, and X ═ a/(a + b);

②R¹and R²In the case where any one of them is a hydrogen atom

(III) in the formula, X is not less than 1 and not more than 10X + Y/4 is not less than 9, wherein X is as defined above, and Y represents R¹And R²The sum of the number of carbon atoms of (a);

③R¹and R²All are not hydrogen atoms

(IV) wherein X, Y has the same meaning as above, 3. ltoreq. 10X + Y. ltoreq.10; wherein the weight ratio of the refrigerant of the component (A) to the base oil of the component (C) is 99/1-10/90.

3. A method for lubricating a compression refrigerator, characterized by using the refrigerator oil composition according to any one of claims 1 or 2.