JPH0971645A - Insulating material for enameled wire in motor for refrigeration compressor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain the subject material containing a carbodiimide group, and capable of improving resistance against a freezer oil and a cooling medium, suppressing crack generation and preventing the increase of oxidation value in a system. SOLUTION: (A) A hydrofluorocarbon is used as a cooling medium. (B) A synthetic lubricating oil of an ester-modified polyoxyalkylene glycol, an ester- modified ether, an ester, etc., having one or more than one ester group in a molecule is used as a freezer oil. And, (C) a compound having one or more than one carbodiimide group is added to an insulating material. Further, it is preferable to use a compound expressed by formula I [R1 is an isocyanate residue; (n1 )=1-100], or that expressed by formula II to formula IV [R2 , R5 and R6 are the same as R1 ; R3 , R4 , R7 and R8 are each a terminal group; (n2 ), (n3 ) and (m) are each 1-100; Y is a compound having a functional group reactive against isocyanate] as the component C. Preferably, it is added e.g. in an amount of 0.1-30 pts.wt. based on 100 pts.wt. of the insulating material.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an insulating material for an enameled wire used as a magnet wire in a motor for a refrigeration compressor, and more specifically, it has resistance to hydrofluorocarbons and a predetermined type of refrigerating machine oil. The present invention relates to an insulating material for an enameled wire of a motor for a refrigeration compressor which is excellent and also has a function of preventing deterioration of the refrigerating machine oil.

[0002]

2. Description of the Related Art Conventionally, dichlorodifluoromethane (CF ₂ Cl ₂ ) having no polarity has been mainly used as a refrigerant in a refrigerating cycle of a refrigerator, a refrigerator, an air conditioner, etc. Therefore, it is mainly used as a refrigerating machine oil. Although mineral oil and the like were used, due to the recent ozone layer depletion problem, the dichlorodifluoromethane containing chlorine atoms cannot be used, and only hydrofluorocarbons (hereinafter abbreviated as HFC) are used instead. It is becoming used.

However, HFC typified by HFC-134a has poor compatibility with conventionally used mineral oil-based lubricating oils, and the mineral oil-based lubricating oils are deposited in a low temperature portion during the refrigeration cycle. , The mineral oil-based lubricating oil does not circulate efficiently in the refrigeration cycle to reduce lubricity, and there is a problem that wear of the compressor increases.
Therefore, the combination of mineral oil lubricant and HFC refrigerant is
It is estimated that it cannot be put to practical use.

Therefore, as a refrigerating machine oil which replaces the mineral oil type lubricating oil, a lubricating oil having one or more ester groups in the molecule such as ester modified polyoxyalkylene glycol type, ester modified ether type or ester type (hereinafter referred to as The use of synthetic lubricants) has been proposed.

On the other hand, HFC-based refrigerants such as HFC-134a are intended for use in refrigerators such as car air conditioners and refrigerators. In the case of refrigerators, the compatibility of refrigerating machine oil and refrigerant is required. In addition, since most of the motors are built-in type in the refrigerant system, deterioration or insulation breakdown of the insulating material for coating the enamel wire etc. used as magnet wires in the built-in motor does not occur, and it does not occur for a long time. It is also necessary to maintain the stability of the insulating material.

[0006]

However, the insulating material such as formalin resin, phenol-modified formalin resin or polyester resin used for coating the enamel wire of the motor is a refrigerant system using the above HFC type refrigerant. In this case, deterioration or peeling (blister or crack) of the surface occurs due to elution into the synthetic lubricating oil or the refrigerant, which causes insulation failure or insulation breakdown, and therefore its use is not preferable.

Polyamideimide, polyimide, polyesterimide, etc., which are said to have excellent performance,
It is hydrolyzed by water contained in the synthetic lubricating oil used together with hydrofluorocarbons, and as a result, an organic acid is generated, and the organic acid accelerates the hydrolysis reaction of the ester group in the synthetic lubricating oil catalytically. Moreover, there is a possibility that the refrigerating capacity may be deteriorated due to the deterioration of the synthetic lubricating oil, which is not sufficient.

The present invention solves the above-mentioned drawbacks of the prior art, and deteriorates or peels the surface of an insulating material for an enamel wire such as a magnet wire by a mixture of hydrofluorocarbons, which is a refrigerant substitute for CFC, and synthetic lubricating oil. A motor for a refrigeration compressor that can prevent the occurrence of (blisters and cracks) and improve the resistance of the insulating material without causing insulation breakdown or insulation failure, and at the same time exhibit the function of preventing the deterioration of synthetic lubricating oil. It was made for the purpose of providing an insulating material for enameled wires.

[0009]

Means for Solving the Problems As a result of intensive studies conducted by the present inventors to solve the drawbacks of the prior art, an insulating material containing a compound having one or more carbodiimide groups was used as an enameled wire such as a magnet wire. It was found that the above object can be achieved by using the above-mentioned coating material, and the present invention has been completed.

That is, the present invention uses, as a refrigerating machine oil, a synthetic lubricating oil having one or more ester groups in the molecule, such as ester-modified polyoxyalkylene glycol-based, ester-modified ether-based or ester-based, using hydrofluorocarbons as refrigerants. An insulating material for an enameled wire of a motor for a refrigerating compressor, which comprises a compound having one or more carbodiimide groups in an insulating material for an enameled wire of a motor for a refrigerating compressor.

The present invention will be described in detail below.

The compound having at least one carbodiimide group in the present invention is represented by the formula:

Embedded image (In the formula, R ₁ is an isocyanate residue, and n ₁ is 1 or more and 10 or more.
(Representing an integer of 0 or less), or a formula (I)

[Chemical 6] (Wherein R ₂ represents an isocyanate residue, R ₃ and R ₄ represent terminal groups, and n ₂ represents an integer of 1 or more and 100 or less), or a group (II) or a formula

[Chemical 7] (In the formula, Y is a residue of a compound having a functional group reactive with isocyanate, R ₅ is an isocyanate residue, R ₆ is an isocyanate residue, or a functional group reactive with a compound providing the residue Y. Of the compound having n, and n ₃ and m each represent an integer of 1 or more and 100 or less) (III), or a formula

Embedded image (In the formula, R ₇ and R ₈ represent terminal groups) (I
V) etc. are included.

R ₁ in the formula of the group (I) is as follows:
The following groups can be exemplified.

Embedded image

It should be noted that n ₁ in the formula of the group (I) is 1
It represents an integer of 100 or more, and more specifically, those in which an isocyanate group is not detected in the infrared absorption (IR) spectrum can be represented by the formula of this group (I), and an isocyanate group can be detected. about,

Embedded image (R ₁ in the formula may not be the same). The same applies to the formula of the above group (III).

Examples of R ₃ and R ₄ in the formula of the above-mentioned group (II) are, for example,

Embedded image Or a residue of a monoisocyanate such as —NH ₂ , —N
HX (X represents an alkyl group), -COOH, -SH,
Functional groups such as -OH

[Chemical 12] Examples thereof include a terminal group of a compound having a functional group reactive with an isocyanate group such as a residue reacted with an isocyanate group.

In the formula of the group (II), n ₂ is
It represents an integer of 1 or more and 100 or less, and this group (I
As R ₂ in the formula of I), the same groups as R ₁ in the formula of the group (I) can be exemplified.

On the other hand, Y in the formula of the above group (III)
Is a residue of a compound having a functional group that is reactive with isocyanate, and can be exemplified by the structures shown below.

Embedded image (In the formula, Z is an alkylene group, a divalent cycloalkyl group,
A divalent cycloalkyl group having a substituent, a divalent aryl group or a divalent aryl group having a substituent, or

Embedded image And a group having a substituent such as a lower alkyl group or a lower alkoxy group on these skeletons. )

That is, the compound represented by the formula of the above group (III) is a copolymer of a compound obtained by reacting the compound giving the residue Y with an isocyanate group and a compound having one or more carbodiimide groups. It represents coalescence.
In the formula of the group (III), n ₃ and m both represent an integer of 1 or more and 100 or less, and this group (I
R ₅ in the formula of II) is the same group as R ₁ in the formula of the group (I), and R ₆ is the same group as R ₁ in the formula of the group (I) or the group (III). The same group as Z in the formula) can be exemplified.

Further, the compound represented by the formula of the above group (IV) is a compound represented by the formula of the above group (II):
It corresponds to the one having n ₂ of 1 synthesized by the reaction of monoisocyanates. The terminal groups R ₇ , R _{8 in the} formula
Is a monoisocyanate residue, and the same groups as the monoisocyanate residue of R ₃ and R ₄ in the formula of the group (II) can be exemplified. R ₇ and R ₈ may be the same or different.

Thus, the insulating material for the enamel wire of the motor for a refrigerating compressor of the present invention is the enamel for a motor for a refrigerating compressor which has been conventionally used with a compound having one or more carbodiimide groups as described above. It is applied by adding it to the insulating material of the wire or by coating the outer circumference of the enamel wire with a compound having one or more carbodiimide groups.

When the carbodiimide compound is added to the insulating material of the enamel wire of the conventional refrigeration compressor motor, the amount of the carbodiimide compound added to the insulating material is 100 parts by weight (solid content) of the insulating material. The amount may be in the range of 0.05 to 50 parts by weight, preferably 0.1 to 30 parts by weight. If the added amount is less than the above amount, the predetermined effect cannot be obtained, and even if a large amount is added, the effect may not be improved so much in some cases, or the properties of the coating may be impaired.

In the present invention, the carbodiimide group is 1
As the insulating material to which the compound having one or more compounds is added, known materials can be used, and examples thereof include polyimide, polyamideimide, tris-2-hydroxyethylisocyanurate-modified polyesterimide, and tris-2-hydroxyethylisocyanurate. Examples thereof include modified polyester amide imide, tris-2-hydroxyethyl isocyanurate modified polyester, polyhydantoin, and polyparabanic acid.

When the outer periphery of the enameled wire is coated with a compound having one or more carbodiimide groups, the compound is preferably of the group (III), and from the aspect of film formability, 100 ≧ n ₃ ≧ 10, 10> m ≧ 1,
Preferably, a compound having a carbodiimide group of 100 ≧ n ₃ ≧ 20, 10> m ≧ 1, or 10> n ₃ ≧ 1,1
00 ≧ m ≧ 10, preferably 10> n ₃ ≧ 1, 100 ≧
a compound having a carbodiimide group of m ≧ 15, or
100 ≧ n ₃ ≧ 10, 100 ≧ m ≧ 10, preferably 1
A compound having a carbodiimide group of 00 ≧ n ₃ ≧ 20 and 100 ≧ m ≧ 15 is preferable.

[0024]

The insulating material of the present invention containing a compound having one or more carbodiimide groups described above has improved resistance to synthetic lubricating oils and refrigerants than conventional ones due to the action of carbodiimide groups, and deterioration or peeling of the surface of the insulating material. (Blisters and cracks) are prevented.

The action of the carbodiimide group is presumed as follows. That is, the main cause of deterioration of the refrigerating machine oil and the insulating material is an organic acid generated by hydrolysis of the ester bond portion of the refrigerating machine oil by the water contained in the refrigerating machine oil, or an ester group, an imide group, an amide in the insulating material. Organic acids generated by hydrolysis of groups (especially low molecular weight substances in insulating materials are easily hydrolyzed and easily eluted in refrigerating machine oil),
It becomes a catalyst that accelerates the hydrolysis reaction, and is in the point of accelerating the deterioration of the refrigerating machine oil and the insulating material, but when a carbodiimide group is present, the carbodiimide group has reactivity with a compound having an active hydrogen group, The produced organic acid is directly trapped, and further, it acts as a dehydration condensation agent to recombine the hydrolyzed ester group, thereby preventing the deterioration of the refrigerating machine oil and the insulating material.

Furthermore, the synthetic lubricating oil, acidic components such as carboxylic acid, hydrogen halide and phosphoric acid produced by decomposition of the refrigerant and additives, and ester bonds in the synthetic lubricating oil exist in the system before they are hydrolyzed. The carbodiimide group existing on the surface or inside of the insulating material can capture the moisture that is generated, and prevent the increase of the oxidation value in the system.

[0027]

The present invention will be described in detail below with reference to examples, but the present invention is not limited to these examples.

The following compounds having a carbodiimide group were used in the examples. Compound 1

[Chemical 15] Compound 2

Embedded image Compound 3

Embedded image Compound 4

Embedded image Compound 5

Embedded image Compound 6

Embedded image Compound 7

[Chemical 21] Compound 8

Embedded image Compound 9

Embedded image Compound 10

Embedded image Compound 11

Embedded image Compound 12

[Chemical formula 26] Compound 13

Embedded image Compound 14

Embedded image Compound 15

[Chemical 29]

Commercially available HFC-1 is used as the synthetic lubricating oil.
Ester oil corresponding to 34a was used.

Examples 1 and 2 Commercially available polyamide-imide varnish (20% N) for coating electric wires.
-Methylpyrrolidone solution), 30% of compound 1 or 8
An N-methyl-pyrrolidone solution was added to 100 parts by weight of the solid content of the polyamideimide varnish so that the solid content of the compound 1 or 8 would be 5 parts to prepare an insulating varnish. An electric wire was covered with this varnish, desolvated, and then annealed to prepare enamel wires (1) and (2).

Example 3 Commercially available polyamide-imide varnish for coating electric wires (20% N
-Methylpyrrolidone solution), a 25% N-methyl-pyrrolidone solution of Compound 1 was added to 100 parts by weight of the solid content of the polyamideimide varnish so that the solid content of Compound 1 would be 30 parts by weight. An insulating varnish was created. An electric wire was coated with this varnish, desolvated, and then annealed to prepare an enamel wire (3).

Examples 4 and 5 Commercially available polyesterimide varnish for coating electric wires (20%
Compound 2 or 10 was added to an N-methylpyrrolidone solution) in an amount of 3 parts by weight based on 100 parts by weight of the solid content of the polyesterimide varnish to prepare an insulating varnish. Electric wires were dipped in this varnish and solidified by removing the solvent to prepare enameled wires (4) and (5).

Example 6 A commercially available refrigerator magnet wire (polyester-nylon wire) was dipped in a 5% perchlorethylene solution of the compound 3 and the solvent was removed, followed by annealing to obtain an enamel surface-coated with the compound 3. A line (6) was obtained.

Example 7 A commercially available polyamide-imide was dissolved in N-methylpyrrolidone to prepare a 25% solution, and a 25% N-methylpyrrolidone solution of compound 4 was added to 100 parts by weight of polyamideimide solution to prepare a solid form of compound 4. An insulating varnish was prepared by adding 7 parts by weight in weight. An electric wire was dipped in this varnish to remove the solvent and then annealed to prepare an enamel wire (7).

Example 8 A commercially available polyamideimide was dissolved in N-methylpyrrolidone to prepare a 25% solution, and a 25% N-methylpyrrolidone solution of compound 11 was added to a solid form of compound 11 with respect to 100 parts by weight of polyamideimide solution. An insulating varnish was prepared by adding 4 parts by weight to the insulating varnish. An electric wire was dipped in this varnish to remove the solvent and then annealed to prepare an enamel wire (8).

Example 9 To 100 g of a 3% N-methylpyrrolidone solution of compound 5,
27 g of commercially available polyamide-imide powder was dissolved to form an insulating varnish. An electric wire was immersed in this varnish to remove the solvent and then annealed to prepare an enamel wire (9).

Examples 10 to 12 Base lines of commercially available refrigerator magnet wires were immersed in a 5% perchlorethylene solution of compound 3, 6 or 9.
Annealing was performed after removing the solvent to give compound 3,
Enameled wire whose surface is coated with 6 or 9 (10), (1
1) and (12) were obtained.

Examples 13 and 14 The base line of a commercially available refrigerator magnet wire was immersed in a 5% N-methylpyrrolidone solution of compound 14 or 15 and the solvent was removed, followed by annealing. Coated enamel wire (13),
(14) was obtained.

Example 15 A commercially available polyesterimide-coated enameled wire was
The enamel wire (15) coated with the compound 12 was prepared by immersing the compound 12 in a 5% tetrahydrofuran solution, removing the solvent, and then annealing.

Example 16 A commercially available polyamide-imide was dissolved in N-methylpyrrolidone to give a 10% solution, and then a 10% N-methylpyrrolidone solution of compound 13 was added to a solid form of compound 13 with respect to 100 parts by weight of polyamideimide solution. An insulating varnish was prepared by adding it so that the total weight was 1 part by weight. An electric wire was dipped in this varnish to remove the solvent and then annealed to prepare an enamel wire (16) coated with the compound 13.

Example 17 A commercially available polyesterimide-coated enameled wire was
It was immersed in a 5% tetrahydrofuran solution of compound 7 and the solvent was removed, followed by annealing to prepare an enamel wire (17) coated with compound 7.

Comparative Example 1 A commercially available refrigerator magnet wire (polyester-nylon wire) was used.

Comparative Example 2 A commercially available polyamide-imide was dissolved in N-methylpyrrolidone to prepare a 25% solution, and then the wire was dipped and the solvent was removed, followed by annealing to obtain a polyamide-imide-coated enamel wire (18). It was created.

Comparative test Enameled wire 3 obtained in Examples 1-17 and Comparative Examples 1-2
g into an autoclave and HFC as a refrigerant in it
-134a, HFC-134a compatible ester oil as synthetic lubricating oil 40g / 300ml, coexistence water 1000
After sealing as ppm and heating at 175 ° C. for 14 days, the presence or absence of cracks in the enamel wire and the total oxidation value of the ester oil were measured. The results are shown in Table 1 below.

[0045]

[Table 1]

The symbols in Table 1 show the following results. ○: No cracks △: Small number of cracks ×: Large number of cracks

[0047]

As is apparent from Table 1 above, the insulating material of the present invention can improve the resistance of the enameled wire for a refrigeration compressor to refrigerating machine oil and refrigerant as compared with the conventional one, and suppress the occurrence of cracks. At the same time, it is possible to prevent the oxidation value from increasing in the system.

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁶ Identification code Internal reference number FI Technical display location H01B 3/30 H01B 3/30 Z // C08G 18/02 NDL C08G 18/02 NDL

Claims (5)

[Claims] 1. An ester-modified polyoxyalkylene glycol-based compound using hydrofluorocarbons as a refrigerant,
In an insulating material for an enamel wire of a motor for a refrigeration compressor, which uses a synthetic lubricating oil having one or more ester groups in a molecule such as an ester-modified ether type or an ester type as a refrigerating machine oil, a compound having one or more carbodiimide groups is used. An insulating material for enameled wire of a motor for a refrigeration compressor characterized by containing. 2. A compound having one or more carbodiimide groups has the formula: (In the formula, R ₁ is an isocyanate residue, and n ₁ is 1 or more and 10 or more.
The insulating material for the enamel wire of the motor for a refrigerating compressor according to claim 1, which is represented by an integer of 0 or less). 3. A compound having at least one carbodiimide group is represented by the formula: (Wherein R ₂ is an isocyanate residue, R ₃ and R ₄ are terminal groups, and n ₂ is an integer of 1 or more and 100 or less, respectively). Insulation material for motor enamel wire. 4. A compound having one or more carbodiimide groups is represented by the formula: (Wherein R ₅ and R ₆ are isocyanate residues, Y is a residue of a compound having a functional group reactive with isocyanate, n
₃ and m are each represented by an integer of 1 or more and 100 or less), and the insulating material for the enamel wire of the motor for a refrigeration compressor according to claim 1. 5. A compound having at least one carbodiimide group is represented by the formula: The insulating material for the enamel wire of the motor for a refrigerating compressor according to claim 1, which is represented by the formula (wherein R ₇ and R ₈ represent terminal groups).