JP2003138167A - Insulating coating material for enamel wire - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an insulating coating material for an enamel wire, improving a working environment and facilitating the disposal waste and enabling the enamel wire to possess required characteristics without using phenolic solvent. SOLUTION: This insulating coating material for the enamel wire is obtained by dissolving a polyester-based resin obtained by reacting a polybasic carboxylic acid or a derivative thereof, with a polyhydric alcohol while regulating the ratio of the equivalent of the carboxyl group to the equivalent of the hydroxy group so as to be 1:(1.2-3.0), in propylene carbonate.

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to an insulating coating for an enameled wire containing a specific polyester resin as a film-forming resin.

[0002]

2. Description of the Related Art Various kinds of enameled wires are used in electric devices such as motors and transformers, and an insulating coating material for enameled wires is indispensable for manufacturing these enameled wires. For example, a heat-resistant E-type polyurethane enameled wire (UEW) has a polyurethane insulating coating, a heat-resistant F-type polyester enameled wire (PEW) has a polyester insulating coating, and a heat-resistant F-H type polyester-imide enameled wire (EIW). Is used for polyester imide insulating paint, and polyamide imide insulating paint is used for polyamide imide enameled wire (AIW) having heat resistance of H or more.

The main solvent of these insulating paints is phenol, cresol, xylenolic acid, etc. in most of the insulating paints except for some polyamideimide insulating paints in which N-methyl-2-pyrrolidone is used. A phenolic solvent is used. These phenolic solvents are
It is a solvent that has a strong irritating odor and is highly toxic and harmful even when compared to the solvents used in other general paints, such as causing chemical damage on skin contact. Phenol is designated as a specific chemical substance, and the Japanese Society for Occupational Health recommends that the allowable concentration of both phenol and cresol be 5 ppm.
Substances containing phenol or cresol are also classified as non-medical deleterious substances. Under such circumstances, when a phenolic solvent is used for paint, great care is required from the management of materials to the management of paint waste.

Therefore, for reasons such as improvement of the working environment in the production and use of insulating paint and measures for waste disposal,
The development of insulating paints that do not use these phenolic solvents has been a problem for many years, and some proposals have already been made, but they are not always satisfactory. For example, a general formula R ₁ O (CHR ₂ —CH such as ethylene glycol monomethyl ether or propylene glycol monoethyl ether is used.
_When a so-called glycol ether solvent represented by ₂ O) _n H (wherein R ₁ and R ₂ in the formula are hydrogen or an alkyl group, and n is an integer), the hydroxyl group at the solvent end is a polyester solvent. Since it reacts with the resin and cleaves the molecular chain of the polyester resin, it cannot be used as a solvent at the time of resin synthesis, and of course, the production conditions of the coating material are greatly restricted. Even if a paint is manufactured by solving this constraint, when the paint is baked into an enamel wire, the same reaction occurs in the baking furnace. Will fall.

It has also been proposed to use a dibasic acid ester such as dimethyl adipate or dimethyl succinate as a solvent. In this case, however, the ester group in the solvent reacts with the polyester resin, so that a glycol ether type is used. The same phenomenon as when using a solvent occurs.

Further, it is possible to use N-methyl-2-pyrrolidone or dimethylformamide, which are used in polyamide imide insulating coatings, as a solvent, but the recommended concentration limit of dimethylformamide is 10 ppm, which is toxic and harmful. However, it is not always satisfactory in terms of improving the working environment in the production and use of insulating paints and measures for waste disposal, because of the odor caused by amine formation at high temperature during baking. .

[0007]

SUMMARY OF THE INVENTION Therefore, an object of the present invention is to improve the working environment in the manufacture and use of insulating paint and to easily take measures for waste disposal without using a phenolic solvent and the like. It is an object of the present invention to provide a polyester-based insulating paint capable of imparting various enamel wire characteristics to a conductor.

As a result of earnest studies to achieve the above object, the present inventor has found that the ratio of the carboxyl group equivalent of the polycarboxylic acid or its derivative to the hydroxyl equivalent of the polyhydric alcohol is
When a polyester resin obtained by reacting these to a certain range is dissolved in propylene carbonate and this solution is used as an insulating paint for enamel wire, it improves the working environment in the production and use of insulating paint, and waste It is possible to form an insulating film that has the same enamel wire characteristics as when using a conventional phenolic solvent, and the concentration is higher than when using a phenolic solvent, which saves resources. The present invention has been completed by finding out that it can be used as a polyester-based insulating paint corresponding to the above.

[0009]

According to the present invention, a polyhydric carboxylic acid or its derivative and a polyhydric alcohol are mixed at a ratio of the carboxyl group equivalent to the hydroxyl group equivalent of 1: 1.
There is provided an insulating coating material for an enamel wire, which is obtained by dissolving a polyester resin obtained by reacting so as to be 2 to 3.0 in propylene carbonate.

[0010]

BEST MODE FOR CARRYING OUT THE INVENTION The present invention will be described in more detail below. The polyester resin used in the present invention can be synthesized by a usual method using a polycarboxylic acid or its derivative and a polyhydric alcohol. In that case, propylene carbonate can also be used as a solvent. In this case, a propylene carbonate solution of the polyester resin having a predetermined concentration can be easily obtained by further adding propylene carbonate to the obtained polyester resin solution, if necessary. When another solvent (other than the phenol solvent) is used, propylene carbonate is added to the reaction solution, or the polyester resin separated from the reaction solution is dissolved in propylene carbonate.

Examples of the polycarboxylic acid or its derivative which is one raw material of the polyester resin in the present invention include aliphatic dicarboxylic acids such as succinic acid, glutaric acid, adipic acid and pimelic acid, terephthalic acid and isophthalic acid. Aromatic dicarboxylic acids such as phthalic acid and naphthalene dicarboxylic acid, for example, aromatic diimide dicarboxylic acids such as trimellitic anhydride and diamines such as diaminodiphenylmethane. Examples thereof include aromatic trivalent carboxylic acids such as mellitic acid, and polyvalent carboxylic acids such as acid anhydrides and lower esterified products thereof.

Considering the heat resistance which is the main characteristic of the enameled wire, aromatic polyvalent carboxylic acids such as terephthalic acid, isophthalic acid, phthalic acid, naphthalenedicarboxylic acid, trimellitic acid and pyromellitic acid are used. It is preferably used, more preferably in combination with an aromatic diimide dicarboxylic acid. The aromatic diimide dicarboxylic acid may be previously synthesized or may be produced in a reaction system for synthesizing a polyester resin. These polyvalent carboxylic acids can be used alone or in combination of two or more.

A method for producing an aromatic diimidedicarboxylic acid is known, and usually aromatic trimellitic anhydride 2
It is produced by reacting 1 mol of aromatic diamine with 1 mol. Examples of aromatic diamines include benzidine, 4,4′-diaminodiphenyl ether and 4,4 ′.
-Diaminodiphenylmethane, p-phenylenediamine, 4,4'-diaminobiphenyl, 4,4'-diaminodiphenylketone and the like can be mentioned, with 4,4'-diaminodiphenylmethane being preferred. Instead of the aromatic diamine, aromatic diisocyanates such as 4,4′-diisocyanate diphenylmethane and 4,4′-diisocyanate diphenyl ether may be used.

The polyhydric alcohol as the other raw material includes, for example, ethylene glycol, diethylene glycol, propylene glycol, 1,3-butanediol,
1,4-butanediol, 1,6-hexanediol,
Aliphatic dihydric alcohols such as neopentyl glycol and spiroglycol, aliphatic trihydric or higher alcohols such as glycerin, trimethylolpropane and pentaerythritol, and cyclic trihydric alcohols such as tris (2-hydroxyethyl) isocyanurate (THEIC). Examples include alcohols having a valency or higher. A combination of dihydric alcohol and trihydric alcohol is preferred. In this case, the dihydric alcohol content is preferably 5 to 95%, more preferably 50 to 90%, based on the total equivalent amount of the alcohol.

The polyester resin used in the present invention is
The ratio of the carboxyl group equivalent of the polyvalent carboxylic acid or its derivative to the polyhydric alcohol is 1: 1.2.
To 3.0, preferably 1: 1.5 to 2.5. When the ratio of the polyhydric alcohol is less than 1.2, the obtained polyester resin is difficult to dissolve in propylene carbonate quickly, and when it exceeds 3.0, the degree of polymerization of the obtained polyester resin is too low to give an enamel wire. In this case, the insulating film has insufficient properties. A polyester resin is produced using the above raw materials, but the production method is not particularly limited, and any conventionally known method for synthesizing a polyester resin can be used.

The insulating coating for enamel wire of the present invention is characterized in that the polyester resin obtained as described above is used as a film forming component and is dissolved in propylene carbonate as a solvent. The resin content in the solution is usually
It is about 15 to 60% by weight. If necessary, various additives such as a curing agent can be added to the insulating coating for enamel wire of the present invention in order to improve heat resistance and other characteristics of the enamel wire.

As the curing agent, Millionate MS-50
A blocked isocyanate compound represented by (Nippon Polyurethane Co., Ltd.) can be used. The blocked isocyanate compound is derived by reacting the isocyanate group of the polyisocyanate compound with a blocking agent for phenols or a blocking agent for alcohols, and the isocyanate is reblocked by heating during the baking of the insulating paint to regenerate the isocyanate. The group reacts with the hydroxyl group of the polyester resin to form a urethane bond to crosslink the polyester resin. The blocked isocyanate compound is usually added in an amount of 50 to 250 parts by weight, preferably 70 to 200 parts by weight, per 100 parts by weight of the polyester resin. If the amount is less than 50 parts by weight, the amount of urethane bonds produced during baking is not sufficient, and if the amount exceeds 250 parts, the isocyanate groups produced are excessive and crosslinking is excessive, resulting in insufficient properties as an enameled wire.

As the blocked isocyanate compound, in addition to Millionate MS-50, for example, Desmodur AP-Stable (manufactured by Bayer), Coronate 2503 (manufactured by Nippon Polyurethane Co.) or Desmodur C.
Commercially available products such as T-stable (manufactured by Bayer) can be mentioned. The enameled wire insulating coating material of the present invention to which a blocked isocyanate compound is added as a curing agent is a polyurethane insulating coating material generally used for heat-resistant E-type polyurethane enameled wire (UEW). Further, when a blocked isocyanate compound is used and a polyester resin having a cyclic imide such as an aromatic diimide dicarboxylic acid composed of trimellitic anhydride and diaminodiphenylmethane as the polyester resin is used, the heat resistance thereof is B type. ~ H species are possible.

Other examples of the curing agent include organic titanium compounds. The insulating coating for an enameled wire of the present invention containing an organic titanium compound as a curing agent can be used as a polyester insulating coating for a heat-resistant type F polyester enameled wire (PEW). Further, when an organic titanium compound is used and a polyester resin having a cyclic imide such as diimidedicarboxylic acid composed of trimellitic anhydride and diaminodiphenylmethane is used as the polyester resin, heat-resistant F to H type polyesterimides are used. It may be a polyesterimide insulating coating used for enamel wire (EIW). The organic titanium compound is usually 1 to 15 per 100 parts by weight of the polyester resin.
It is mixed in a ratio of 2 parts by weight, preferably 2 to 8 parts by weight.
If the amount is less than 1 part by weight, sufficient curing will not be performed during baking, and if it exceeds 15 parts by weight, the curing will be excessive, and the properties as an enamel wire will be insufficient in both cases.

Examples of the organic titanium compound include titanium esters such as tetraisopropyl titanate and tetranormal butyl titanate, titanium chelates such as titanium acetyl acetylate and titanium lactate, and titanium acylates such as hydroxytitanium stearate. Can be mentioned. Any of the curing agents can be used alone or in combination of two or more.

As additives other than the curing agent, for example, resins such as phenol resin and epoxy resin, metal soaps called desiccant, various paint additives called leveling agent, and dyes and pigments Can be appropriately added to the insulating paint of the present invention. Further, when a propylene carbonate solution of a polyester resin is used as an insulating coating for an enamel wire, an alkylbenzene such as xylene or trimethylbenzene can be used together as a diluting solvent in a range where the insulating coating is stable. Furthermore, within the range that the characteristics of the present invention are not lost, a ketone solvent such as cyclohexanone, an alcohol solvent such as henzyl alcohol, the glycol ether solvent described above, the dibasic acid ester solvent described above, and N-methyl-2. It is also possible to use pyrrolidone, dimethylformamide and the like.

The toxicity of the insulating paint of the present invention is significantly lower than that of the conventional insulating paint using a phenolic solvent.
No special management is required unlike conventional insulating paints that use phenolic solvents. Further, as shown in Examples described later, the coating material has a high concentration and is effective for resource saving. By applying and baking the insulating coating material of the present invention on a conductor such as annealed copper wire according to a conventional method, it is possible to obtain an enamel wire having insulating properties equivalent to those obtained with the conventional insulating coating material with a phenolic solvent. it can.

[0023]

EXAMPLES The present invention will be specifically described below with reference to examples and reference examples, but the present invention is not limited to these examples. "%" In the following text is based on weight. In addition, the test of the insulated wire was conducted in appearance, adhesion, flexibility,
Regarding the softening point and dielectric breakdown voltage, JIS C3003-
1984 (test method for enamel copper wire and enamel aluminum wire).

Example 1 179 g of ethylene glycol and glycerin 4 were placed in a reaction vessel.
4 g, 409 g of trimellitic anhydride, 119 g of 4,4′-diaminodiphenylmethane and 0.7 g of tetrabutyl titanate as a catalyst were added, and the mixture was kept at 150 ° C. for 5 hours and then heated to 200 ° C. over 5 hours. The reaction is carried out at a temperature for 5 hours, and 461 g of propylene carbonate and 68 g of Hisol # 100 manufactured by Nisseki Chemical Co., Ltd. are added to the resulting polyester resin solution to obtain a resin solution having a nonvolatile content of 50%. Further, 3% by weight of tetrabutyl titanate was added to the resin component to obtain a polyester-based insulating coating material having a nonvolatile content of 50% by weight and a viscosity of 40 dPa · s at 30 ° C.
The obtained polyester-based insulating paint, effective furnace length 2.5m
A horizontal baking furnace, baking temperature of 500 ° C, coating of 6 times of die, and coating and baking of 0.32 mm diameter soft copper wire under the conditions of a drawing speed of 24 m / min.
Measurement was performed according to S C3003, and the results are shown in Table 1.

Example 2 In a reaction vessel, 74 g of ethylene glycol, 313 g of tris-2-hydroxyisocyanurate, 218 g of dimethyl terephthalate, 144 g of trimellitic anhydride, 4,
Add 74 g of 4'-diaminodiphenylmethane and 0.7 g of tetrabutyl titanate as a catalyst, and add 5 at 150 ° C.
After holding for a period of time, the temperature was raised to 200 ° C over 6 hours, and the reaction was carried out at this temperature for 5 hours. To the resulting polyester resin solution, 588 g of propylene carbonate and 65 g of Hisol # 100 manufactured by Nisseki Chemical Co. 50% resin solution. Furthermore, 3% by weight of tetrabutyl titanate and 2% by weight of phenol formaldehyde resin were added to the resin content, and the nonvolatile content was 50% and the viscosity at 30 ° C was 5%.
A polyester-based insulating paint of 0 dPa · s was obtained. The characteristics of the obtained insulating paint were measured in the same manner as in Example 1. The results are shown in Table 1.

Example 3 500 g of a 50% solution of the polyester resin of Example 1
Coronate 2503 (manufactured by Nippon Polyurethane Co.) 40
0 g, propylene carbonate 280 g, xylene 13
5 g and zinc naphthenate 3 g were charged and uniformly dissolved at 80 ° C., non-volatile content 50%, viscosity at 30 ° C. 30 d
An insulating paint of Pa · s was obtained. The characteristics of this insulating paint were measured in the same manner as in Example 1. The results are shown in Table 1.

Reference Example 1 179 g of ethylene glycol and 4 of glycerin were placed in a reaction vessel.
4 g, 409 g of trimellitic anhydride, 119 g of 4,4′-diaminodiphenylmethane and 0.7 g of tetrabutyl titanate as a catalyst were charged and reacted in the same manner as in Example 1, and 699 g of cresol and 1 day of cresol were added to the produced polyester resin solution. 262 Hisol # 100 made by Ishigaku
g to make a resin solution having a nonvolatile content of 40%. Further, 3% by weight of tetrabutyl titanate was added to the resin content, and the nonvolatile content was 40% by weight and the viscosity at 30 ° C. was 43 dPa · s
To obtain a polyester-based insulating paint. The resulting insulating coating was tested as in Example 1. The results are shown in Table 1.

Reference Example 2 In a reaction vessel, 74 g of ethylene glycol, 313 g of tris-2-hydroxyisocyanurate, 218 g of dimethyl terephthalate, 144 g of trimellitic anhydride, 4,
74 g of 4'-diaminodiphenylmethane and 0.7 g of tetrabutyl titanate as a catalyst were charged and reacted in the same manner as in Example 2, and 719 g of cresol and Hisol # 100 manufactured by Nisseki Chemical Co., Ltd. were placed in a reaction vessel containing the obtained polyester resin. Add 79 g to make a resin solution having a nonvolatile content of 50%. Furthermore, 3% by weight of tetrabutyl titanate and 2% by weight of phenol formaldehyde resin were added to the resin content, and the nonvolatile content was 45% and the viscosity at 30 ° C. was 52 dPa.
s polyester-based insulating paint was obtained. The resulting insulating coating was tested as in Example 1. The results are shown in Table 1.

Reference Example 3 500 g of a 40% solution of the polyester resin of Reference Example 1
And Coronate 2503 (manufactured by Nippon Polyurethane Co.) 32
0 g, 235 g of cresol, 135 g of xylene and 3 g of zinc naphthenate were charged and uniformly dissolved at 80 ° C. to obtain an insulating coating material having a nonvolatile content of 45% and a viscosity of 31 dPa · s at 30 ° C. The resulting insulating coating was tested as in Example 1. The results are shown in Table 1.

[0030]

[0031]

The toxic and harmful effects of the insulating paint of the present invention are significantly lower than the toxic and harmful effects of the conventional phenolic solvent-based insulating paints, and special control is required unlike the conventional phenolic solvent-based insulating paints. do not need. Further, as in the above-mentioned embodiment, the coating material is highly concentrated and is effective for resource saving. By applying the insulating coating material of the present invention to a conductor such as annealed copper wire according to a conventional method, it is possible to obtain the same enamel wire characteristics as those obtained with the conventional insulating coating material using a phenolic solvent.

   ─────────────────────────────────────────────────── ─── Continued front page    (72) Inventor Hiroshi Nakamura             1-7-6 Nihonbashi Bakurocho, Chuo-ku, Tokyo Large             Within Nissei Chemical Co., Ltd. (72) Inventor Masao Ikeda             1-7-6 Nihonbashi Bakurocho, Chuo-ku, Tokyo Large             Within Nissei Chemical Co., Ltd. F-term (reference) 4J038 DD041 DG302 JA67 JC38                       KA03 KA04 KA06 PB09 PC02

Claims (3)

[Claims] 1. A polyester system obtained by reacting a polyhydric carboxylic acid or its derivative with a polyhydric alcohol so that the ratio of their carboxyl group equivalents to hydroxyl group equivalents is 1: 1.2 to 3.0. An insulating coating material for an enamel wire, which is obtained by dissolving a resin in propylene carbonate. 2. The insulating paint for an enameled wire according to claim 1, wherein the blocked isocyanate compound is contained in a proportion of 50 to 250 parts by weight per 100 parts by weight of the polyester resin. 3. The insulating coating for an enameled wire according to claim 1, wherein the organic titanium compound is contained in an amount of 1 to 15 parts by weight per 100 parts by weight of the polyester resin.