JPH04202597A - Lubricating agent for hydrogenated fluorocarbon refrigeration medium - Google Patents

Abstract

PURPOSE:To obtain a lubricating agent consisting of a specific cyclic phosphonitrile ester, having high viscosity index and low fluidity and good compatibility with a hydrogenated fluorocarbon refrigeration medium. CONSTITUTION:The objective lubricating agent consisting of a cyclic phosphonitrile ester expressed by the formula [ n is 3-4; X and X' are R1-(OR2) l-O-(R1 is 1-12C alkyl or 6-18C aryl; R2 is 2-4C alkylene; OR2 is alone bound or bound in randomly combined state or in block-combined state; 1 is 2-35)]. Furthermore, the hydrogenated fluorocarbon refrigeration medium includes 1,1-dichloro-2,2,2-trifluoroethane or 1,1,1,2-tetrafluoroethane, etc.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a lubricant for a hydrogen-containing fluorocarbon refrigerant.

More specifically, the present invention relates to a lubricant for refrigerators and the like that has a polyglycol chain and has a phosphonitrile skeleton and has excellent lubricity, and has good compatibility with hydrogen-containing fluorocarbon refrigerants.

[Prior Art] In general, a refrigerator is a device that repeatedly liquefies and vaporizes a refrigerant to create a low temperature through the action of a compressor, and is called an evaporator.

It consists of a compressor, an expansion valve, etc., through which refrigerant and lubricant circulate, forming a cycle that repeatedly absorbs and releases heat.

Refrigerating machine oils that are generally used include naphthenic or paraffinic mineral oils or alkylbenzenes to which antioxidants, metal deactivators, wear inhibitors, corrosion inhibitors, and the like are added.

Therefore, the required performance for the lubricant is good compatibility with the refrigerant, stability in the coexistence of the refrigerant, and lubricity for equipment (prevention of wear and seizure).

Refrigerators use CFCs composed of fluorine, chlorine, and carbon as refrigerants, such as trichloromonofluoromethane (R1
1), dichlorodifluoromethane (R12), monochlorodifluoromethane (R22), and other fluorocarbons are used.

Recently, in connection with the problem of stratospheric ozone depletion, it was agreed to curb the use of CFCs under the Montreal Agreement. Therefore, as an alternative to CFCs, the United States Environmental Protection Agency (EPA) recommends 1,1-dichloro-2,
2,2-trifluoroethane (HCFC-123), 1
-Chloro-1,2,2,2-tetrafluoroethane (H
CFC-124), 1,2-dichloro-2,2-difluoroethane (HCFC-132b), l-chloro-2,
2,2-trifluoroethane (HCFC-1338)+
11 11 1.2-tetrafluoroethane (HC
Six types are proposed: FC-134a) and 1,1-dichloro-1-fluoroethane (HCFC-14lb). Among these, 1,1,1,2-tetrafluoroethane is being considered as a substitute for R-12 because it has similar physical properties to R-12.

Among hydrogen-containing fluorocarbon refrigerants, polyalkylene gellicols, which can be used for 1.1.1.2-tetrafluoroethane, were published in DuPont Research Disclosure No. 17433, October 1973. and further describes its use in polyalkylene glycol systems in U.S. Pat. No. 4,755,316, July 1988.

In Japan as well, attention has been focused on polyalkylene glycol-based lubricants, and various polyalkylene glycol derivatives have been developed, as disclosed in JP-A-1-198,694 and JP-A-1-259.
, No. 093, No. 1-259.094, No. 1-
No. 259,095, No. 2-43,290, No. 2-84,491, No. 2-102.296, No. 2-140.295, No. 2-242,888
No. 2-258.895 and No. 2-269
．． It is described in Publication No. 195.

[Problems to be Solved by the Invention] In conventional techniques, the lubricity is generally insufficient, and there are many examples in which anti-wear agents are added to improve the lubricity. The present invention has a high viscosity index and low pour point.

The purpose is to provide a lubricant that is compatible with hydrogen-containing fluorocarbons.

[Means for Solving the Problems] In order to achieve the above object, the hydrogen-containing fluorocarbon refrigerant lubricant of the present invention is constructed as follows.

The following general formula (1) is selected from the following formula in which n is 3 to 4 and x and x' are represented by one or two groups, where R1 is the number of carbon atoms R1-(OR2) 1-0- An alkyl group having 1 to 12 carbon atoms, or an aryl group having 6 to 18 carbon atoms, R2 represents an alkylene group having 4 to 4 carbon atoms, and the alkylene group may be individual, random, or a combination of blocks.

The molecular weight is 2 to 35, preferably 3 to 20, and the molecular weight is 200.
~1700, R1-(OR2)L-〇-
The viscosity of the group at 40° C. is preferably 7 to 30 I11a”/S.

The final lubricant composition of the present invention contains the required antioxidants,
It may also contain a metal deactivator and a corrosion inhibitor, and these can also be used in combination.

Here, the amine antioxidants include phenyl alpha naphthylamine and its derivatives, diphenylamine and its derivatives, 2,6-di-tert-butyl-alpha dimethylamino-para-cresol, 4,4'-
Tetramethyldiaminodiphenylmethane, phenolics include 2,6-di-tert-butyl para-cresol,
4.4'-methylenebis(2,6-di-tert-butylphenol), octadecyl-3-(3,5-di-
tertiary-butyl-4-hydroxyphenyl)-propionate, pentaerythrityl-tetrakis [3-(
3,5-di-tert-butyl-4-hydroxyphenyl)propionate, 1,3,5-trimethyl-2
,4,6-tris(3,5-di-tert-butyl-
Examples include 4-hydroxybenzyl)benzene, bis(3,5-di-tert-butyl-4-hydroxybenzyl) sulfide, and 4,4-thiobis(3-methyl-6-tert-butylphenol).

Metal deactivators include benzotriazole and its derivatives, imidazole, thiazole, thiadiazole derivatives, N,N'-disalicylidene-1,2-propanediamine, etc., and corrosion inhibitors include sodium alkylbenzenesulfonate, calcium, and barium. salts, sodium nonylnaphthalene sulfonate, calcium, barium salts, alkylamine salts of phosphoric acid esters, alkyl and alkenyl esters of alkenylsuccinates, and the like. These additives may be used alone or in combination, and the amount of additives added is preferably 0.01 to 5% by weight.

In addition, there are many examples in which phosphoric acid ester is generally added as an anti-wear agent, but the compound of the present invention contains phosphorus, has anti-wear performance, and does not require the addition of an anti-wear agent. The lubricity of compressor bearings and parts of pistons/cylinders is as effective as or better than polyalkylene glycol-based products containing anti-wear agents.

The compound represented by the formula (1) can be produced, for example, as follows.

Synthesis Example 1 324 g (2 moles) of butyl diglycol and 3.3 g of potassium hydroxide (approximately 1% by weight of butyl diglycol) as a catalyst were charged into an autogelap, and the mixture was heated to a pressure of 3 with nitrogen gas.
After replacing the mixture with kg/ffl three times, the mixture was heated to 120°C.

Subsequently, 464 g (8 mol) of propylene oxide was introduced over a period of about 8 hours while keeping the internal pressure at 8 kg/cd or less, and then kept at 140° C. for 3 hours to complete the reaction and then taken out. Neutralize alkaline content with phosphoric acid and wash with water at a temperature of 140°C
Dehydrated by heating and filtered through Celite to give 772 g, yield 9.
8% product was obtained.

The physical properties of the product are: moisture 0.05% by weight, pH 6.8, hydroxyl value 145.7, viscosity 40°C 10°4nn2/S,
The freezing point was -60°C or lower.

Next, 235 g (0°61 mol) of the above product (molecular weight calculated from hydroxyl value, molecular weight 385.04) and 500 rr + Q of toluene were placed in a Yotsuro flask equipped with a condenser, a stirrer, and a thermometer, and under cooling, metallic sodium 15 g (0.65 mol) of the powder was added and reacted at 40° C. for 4 hours until the sodium was completely dissolved. To this reaction solution was added 36.5 g of phosphonitrile chloride trimer (melting point 112-114°C) dissolved in 250 mfl of toluene.
A solution of (0.105 mol) was added dropwise at 50°C, and the reaction was carried out under reflux at a temperature of 110 to 115°C for 4 hours. A small amount of water and dilute hydrochloric acid were added to the reaction product for azeotropic dehydration, and the resulting sodium chloride was centrifuged, washed with water, dried, and toluene removed under reduced pressure to obtain 235 g of a pale yellow transparent product.

When the hydroxyl value was measured using JIS KOO70, it was found to be 0.
According to the analysis method for chlorine content according to JIS K2241 in No. 3, the chlorine content was 0.02%.

Infrared spectrum analysis (lR810 manufactured by JASCO Corporation)
As a result of 3250 mark-1 OH absorption disappears,
1,424 c, which is the absorption of c-o-p Arifatesoku
s-1 appeared, indicating the structure of hexakis (butyldioxyethylenetetraoxypropyleneoxy) cyclic triphosphonitrile ester. The density of this substance is 0.
99/g■3, viscosity 40℃ 75.7mm2/S, 10
0'C114°8+nm''/S, pour point -47.5°C.

Synthesis Example 2 162g of butyl diglycol (1,0
About 1% by weight of butyl diglycol (1.65 g) and potassium hydroxide as a catalyst were charged, the mixture was replaced with nitrogen gas three times at a pressure of 3 kg/aj, and then heated to 120°C.

Subsequently, 465 g (8.01 mol) of propylene oxide was introduced over a period of about 8 hours while keeping the internal pressure at 8 kg/d or less, and then kept at 140° C. for 3 hours to complete the reaction and then taken out.

The alkali content was neutralized with phosphoric acid, washed with water, heated to a temperature of 140°C, dehydrated, and filtered through Celite to yield 608g, yield 97.
% product was obtained.

The physical properties of the product are water 0.05% by weight, pH 7.0, and hydroxyl value 90. Viscosity: 21.7 m2/S at 40°C.

The freezing point was -60°C or lower.

Next, 374 g (Q.

60 mol) and 700 mQ of toluene were charged, 14.2 g (0,617 mol) of metallic sodium pieces were added under cooling, and the mixture was reacted at 40°C for 4 hours until the sodium was completely dissolved.

36 g of phosphonitrile chloride trimer (melting point 112-114°C) dissolved in 250 mQ of toluene was added to this reaction solution.
(0,104 mol) (7) solution was added dropwise at 50°C, and the reaction was carried out under reflux at a temperature of 110 to 115°C for 4 hours.

A small amount of water and diluted hydrochloric acid are added to the reaction product for azeotropic dehydration, and the sodium chloride produced is centrifuged and then washed with water.

It was dried and mixed with toluene under reduced pressure to obtain 370 g of a pale yellow transparent liquid.The hydroxyl value was measured in the same manner as in Synthesis Example 1, and it was found to be 0.2, and the chlorine content was 0.03%. Ta.

As a result of infrared spectrum analysis, 3250 (!M-”O
Almost no H absorption was observed, and 1424al-1, which was the absorption of c-op arifatenocc, appeared, showing the structure of hexakis (butyldioxyethylene octaoxypropyleneoxy) cyclic phosphonitrile ester.

The density of this material is 0.98 g/cn at 15/4°C.
3. Viscosity 40°C 155avn”/S, 100°C 29.
4+m'/S, pour point=50°C.

Synthesis Example 3 In the same manner as in Synthesis Example 1 above, 437 g (2.0 mol) of 2-ethylhexyldiglycol and 4.4 g of 2-ethylhexyldiglycol (approximately 1% by weight) and potassium hydroxide as a catalyst were placed in an autoclave. Preparation, pressure with nitrogen gas 3
After replacing the mixture with 3 kg/ffl, it was heated to 120°C. Subsequently, 465 g (8.01 mol) of propylene oxide was introduced over a period of about 8 hours while maintaining the internal pressure at 8 kg/a# or less, and then kept at 140° C. for 3 hours to complete the reaction and then taken out. Neutralize the alkaline content with phosphoric acid, and after washing with water, reduce the temperature to 1.
Heated to 40℃, dehydrated, filtered through Celite, 883g
, the product was obtained with a yield of 98%. The physical properties of the product are: moisture 0.03% by weight, pH 6.8, hydroxyl value 125°, viscosity 4.
The temperature was 11.5 strokes 2/S at 0°C, and the freezing point was -60°C or lower.

Next, 270 g (0°602 mol) of the above product (molecular weight calculated from hydroxyl value, molecular weight 448.8) and 500 m Q of toluene were placed in a Yotsuro flask equipped with a condenser, a stirrer, and a thermometer, and the mixture was cooled. 14 g (0,609 mol) of metallic sodium pieces were added and reacted at 40° C. for 4 hours until the sodium was completely dissolved.

Phosphonitrile chloride trimer (melting point 112-114°C) dissolved in toluene 250 mA was added to this reaction solution.
5.5 g (0.102 mol) of the solution was added dropwise at 50°C, and the reaction was carried out at a temperature above reflux of 110 to 115°C for 4 hours. A small amount of water and dilute hydrochloric acid were added to the reaction product for azeotropic dehydration, and the resulting sodium chloride was centrifuged, washed with water, dried, and poured with toluene under reduced pressure to obtain 270 g of a pale yellow transparent liquid.

When the hydroxyl value was measured in the same manner as in Synthesis Example 1, it was found to be 0.
2, and the chlorine content was 0.02%.

As a result of infrared spectrum analysis, OH of 3250 am-1
The absorption of almost disappeared, and 1424■-1, which is the absorption of c-op Alifatec, appeared, indicating the structure of hexakis (2-ethylhexyldioxyethylethylenetetraoxypropyleneoxy) cyclic phosphonitrile ester. Ta.

The density of this material is 0.98 g/am' at 15/4°C.
, viscosity 40℃ 84Trn2/S 100'C15,
The pour point was -50° C. at 86 m”/S.

[Function] The present invention is a cyclic phosphonitrile ester comprising a polyalkylene glycol and a cyclic phosphonitrile chloride trimer or tetramer.

This compound contains an inorganic substance having 3 to 4 phosphonitrile groups approximately at the center of the bond chain, and is compatible with similar inorganic metals and easily adsorbs them.

However, since this phosphonitrile is esterified and bonded to polyalkylene gelylcols, it does not have a hydroxyl group,
In addition to exhibiting good compatibility with hydrogen-containing fluorocarbon refrigerants, it also has an equivalent characteristic of low-temperature fluidity and wide range of viscosity-temperature characteristics, which are the advantages of polyalkylene glycols.

[Example 7] In explaining specific examples of the present invention below, the properties of the base materials used in Synthesis Examples 1, 2.3 and Comparative Examples are shown in Table 1.

Incidentally, it goes without saying that the present invention is not limited to the examples shown below.

Example 1 (Seizing load resistance performance) The lubricating performance of the lubricant of the present invention was measured by Falex anti-seizure load test. The results are shown in Table 2 of the appendix.

The test method is based on ASTM D3233, oil temperature is 25℃,
The seizure load (bond) was measured after a break-in operation for 5 minutes with a load of 150 bonds (68 kg).

Example 2 (Thermal Stability: Shield Tube Test) Samples 1 to 5 and 1 g each of 1.1.1.2-tetrafluoroethane were placed in a glass tube, and pieces of iron, copper, and aluminum alloy were placed in the glass tubes. After placing one sheet of each sample and sealing them, the samples were heated for 14 days (336 hours) at a temperature of 175° C., and then the discoloration of the samples was measured using JIS K2580 (ASTM color test method).

(See attached table 3) Metal piece material: Steel JIS G3141 Copper
JIS H3100 aluminum alloy
JIS H4000 Shape of metal piece: 2m long, 2mm wide, 40 fields long.

Example 3 (Compatibility) Low-temperature separability between the refrigerant lubricant and refrigerant according to the present invention was determined wt.
I guessed it.

0.5g of sample and 1,1.1°2- as a refrigerant in a glass tube
After taking 2.5 g of tetrafluoroethane and sealing it, it was placed in a constant temperature bath, and the temperature was cooled and heated at 1°C per minute.
The results of measuring the two-layer separation temperature are shown in Appendix Table 4.

[Effects of the Invention] The hydrogen-containing refrigerant lubricant of the present invention can be used as a refrigerating machine lubricant with excellent lubrication performance (load-bearing performance) and compatibility with hydrogen-containing fluorocarbon refrigerants. In particular, 1.1.1
, 2-tetrafluoroethane, does not separate from the refrigerant at low temperatures, and is a highly stable lubricant for refrigeration equipment.

November 30, 1990 Patent applicant Maruwa Bussan Co., Ltd.
Takateru Izura List 4 Director General of the Patent Office Satoshi Uematsu 1, Relationship with the indication case Patent applicant address 2-7-19 Kyobashi, Chuo-ku, Tokyo Name Maruwa Bussan Co., Ltd. Representative Miharu Kikuchi ( (1 other person) 4. Agent Address: 1-5-4 Nishiikebukuro, Toshima-ku, Tokyo Amend the "Claims" section of the specification and "Invention (1) Claims as attached.

(2) The 6th line on page 6 of the specification to the 8th line on the same page are corrected as follows.

"The lyl group and R7 represent an alkylene group having 2 to 4 carbon atoms, and the OR2 group may be an oxyalkylene group having 2, 3, or 4 carbon atoms alone or in a random or block combination." (3) On page 8, line 16 of the specification, “
Correct the phrase "autogelape" to "autoclave."

(4) On page 14, line 13 of the specification, “Sakis (2-ethylhexyldioxyethylene”) has been replaced with “Sakis (2-ethylhexyldioxyethylene”).
- Correct as ethylhexyldioxyethylene J.

(Attachment) "Claim (1) General formula, n is 3 to 4, and x and x' are represented by the following formula R□-(○R
2) A lubricant for a hydrogen-containing fluorocarbon refrigerant, which is a cyclic phosphonitrile ester formed by a 11-◯- group and in which x and x' are one or two groups.

(2) Ro represented by the R1-(ORz)2-0- group is an alkyl group having 1 to 12 carbon atoms or an aryl group having 6 to 18 carbon atoms, and R2 is a linear or branched group having 2 to 4 carbon atoms. represents an alkylene group, and the OR2 group represents a single, random or block combination bond.

The lubricant according to claim 1, wherein 2 is a number from 2 to 35.

(3) The hydrogen-containing fluorocarbon refrigerant is 1,1-dichloro-2,
2,2-trifluoroethane = 1-chloro-1,2,2
,2-tetrafluoroethane:1,2-dichloro-2,
2-difluoroethane: 1-chloro-2,2,2-trifluoroethane: 1.1.1.2-tetrafluoroethane = 1.1-dichloro-1-fluoroethane: 1-chloro-1,1-difluoroethane The lubricant according to claim 1, which is 1.1-difluoroethane or trifluoroethane. ”

Claims (3)

[Claims] (1) General formula ▲ There are mathematical formulas, chemical formulas, tables, etc. ▼ In the formula, n is 3 to 4, X and X' are represented by the following formula R_1-(OR_2)_l-O-, and
, a cyclic phosphonitrile ester in which X' is one or two groups, and a hydrogen-containing fluorocarbon refrigerant lubricant. (2) R_1-(OR_2)_l-O- group is an alkyl group having 1 to 12 carbon atoms or 6 to 12 carbon atoms.
In the 18 aryl groups, R_2 represents a linear or branched alkylene group having 2 to 4 carbon atoms, and the alkylene group of R_2 represents one or more types of single, random or block polymer chains. The lubricant according to claim 1, wherein l is a number from 2 to 35. (3) The hydrogen-containing fluorocarbon refrigerant is 1,1-dichloro-2,
2,2-trifluoroethane: 1-chloro-1,2,2
,2-tetrafluoroethane:1,2-dichloro-2,
2-difluoroethane: 1-chloro-2,2,2-trifluoroethane: 1,1,1,2-tetrafluoroethane: 1,1-dichloro-1-fluoroethane: 1-chloro-1,1-difluoroethane The lubricant according to claim 1, which is 1,1-difluoroethane or trifluoromethane.