JPS6281463A - Water-soluble insulating coating - Google Patents

Abstract

PURPOSE:To obtain a water-soluble insulating coating which compares favorably in electrical, mechanical and thermal characteristics with a conventional organic- solvent type insulating coating comprising a polyester containing imido groups, by the addition of a polybasic acid to a specified esterimide resin, followed by neutralization of the adduct with a basic compound. CONSTITUTION:A water-soluble insulating coating prepared by the addition of a polybasic acid containing one anhydride group in a molecule to an esterimide resin of a hydroxyl value of 110-300 and dissolving the adduct in water with a basic compound. Preferably, the esterimide resin is obtained by reacting polyhydric alcohols including at least trihydric alcohol with an imidic acid which contains imido groups and is composed of an aromatic dicarboxylic acid and its derivative, trimellitic anhydride, and a diamine, in the proportion of 1.2-2.1 equivalents of the polyhydric alcohols to one equivalent of the carboxyl group.

Description

DETAILED DESCRIPTION OF THE INVENTION (a) Industrial Application Field The present invention relates to a water-soluble insulating paint used for electrical insulation or for coating electric wires.

(1)) Conventional technology Imide group-containing polyester coated electric wires, which are coated with an insulating paint containing imide-modified polyester resin and polyester imide resin (hereinafter referred to as imide group-containing polyester resin) as coating components and baked, are used to reduce the size of equipment. Due to its superior heat resistance, electrical insulation, and mechanical properties, it is widely used in general-purpose and consumer electrical equipment.

However, these paints are not that good! Due to the high molecular weight and hydrophobic nature of the components, most of them use organic solvents such as phenols, which are expensive and harmful.

For this reason, attempts have been made to make the coating film components of this type of insulating paint water-soluble.

The first paint has a trivalent or higher polycarboxylic acid stranded in the main chain as a water-soluble portion.

Further, the second paint has a sufficiently large OH/COOII ratio and is made water-soluble before the resin skeleton becomes hydrophobic by extremely limiting the molecular weight.

(c) Problems that the invention seeks to solve However, the first paint induces plasticization of 1:, u4, and as a result, the thermal and mechanical properties not only decrease; , reaction of carboxyl groups, etc., gels to a molecule ml that exhibits characteristics that can sufficiently compete with organic solvent-based imide group-containing polyester insulation paints, and therefore exhibits sufficient time-opening properties. There was a fundamental problem that there was no such thing.

In addition, the second paint has low molecular weight coating components, and as a result of the second paint, there are problems such as the insulation film being thermally and mechanically fragile compared to organic solvent-based imide group-containing polyester insulation paints. there were.

(d) Means for solving the problem As a result of intensive studies, the present inventors produced an imide group-containing polyester f31 resin that is essentially equivalent to an organic solvent-based imide group-containing polyester resin. resin side chains,
Alternatively, the drawbacks mentioned above are solved by using a completely new technical means of adding a polycarboxylic acid containing only one anhydride group to the terminal hydroxyl group and opening the ring to make it water-soluble. .

That is, the present invention adds a polybasic acid containing only one anhydride group per molecule to an esterimide resin having a hydroxyl value of 110 to 300, and dissolves this adduct in water with a basic compound. It is characterized by:

As the ester imide resin, an imidic acid containing an imide group consisting of trimellitic anhydride and cyamine and a polyhydric alcohol containing a polyhydric alcohol of trihydric or higher valence are added at 1°2=2. It is preferable to use a high molecular weight imide group-containing polyester resin obtained by reacting at a ratio of 1 equivalent.

In particular, as -1- esterimide 431 fat, c)°
aromatic dicarboxylic acid and its derivatives, trimellitic anhydride; imide J consisting of cyamine, 1-mide acid containing ζ, and polyhydric alcohol containing polyhydric alcohol of 3 or more than 2 to 1 equivalent of carboxyl group. It is most preferable to use a high molecular weight imide group-containing polyester resin obtained by reaction at a ratio of 1.2 to 2.1 equivalents, since it has extremely excellent electrical insulation, heat resistance, mechanical properties, etc. It is.

The present invention will be explained in detail below.

The high molecular weight imide group-containing polyester resin used in the present invention is obtained by adding a polybasic acid containing only one anhydride group in the molecule to an ester imide resin with a hydroxyl value of 11 (1.-3+10). .

The esterimide resin having a hydroxyl value of 110 to 300 can be obtained using generally known materials and methods.

That is, this ester imide resin is composed of an imide acid containing an imide group consisting of trimellitic anhydride and a diamine, and a trivalent or higher-valent acid.
It is obtained by reacting a polyhydric alcohol containing L polyhydric alcohol at a ratio of 1.2 to 2.1 equivalent to 1 equivalent of carboxyl group.

Trimellitic anhydride used in the present invention is a known substance and has the structural formula (1) shown below.

Structural formula (1) is 58 = 520, such as polymethylene diamine, trimethylhexamethylene diamine, polyether diamine, menthene diamine, noaminocyclohexylamine, isophoronoamine, +o phenylene diamine, p-phenylene diamine , m-xylylene diamine, p-xylylene diamine, 4.4'-noamino diphenylmethane, 4゜4'-diaminodiphenyl ether, 3.4'-di7mi/nophenyl ether, etc. Diphenylmethane, diaminodiphenyl sulfone, noamino diphenyl thioether, diaminobenzophenone, 4.4'-di(3-aminophenoxy)-7enyl sulfone, 4.4
゛-Di(3-aminophenoxy)diphenylpropane, 4,4'-di(3-aminophenoxy)diphenylhexafluoropropane, 4,4'-diaminodiphenylpropane, paraphenylene 77mine, meta-7elendiamine, benzidine, 3゜3′-dimethylbenzidine,
3.3'-di,nodoxy4.4'-diaminodiphenylmethane, 3.3'-dimethyl-4,41-diaminodiphenylmethane, 2.2-bis(4-7minophenyl)propane, 2゜2-bis[4 -(4-aminophenoxy)phenyl 1-hexafluoropropane, 1,3-bis(aminophenoxy)benzene, etc., and these may be used alone or in combination of two or more.

Furthermore, the polyhydric alcohol used in the present invention has a molecular weight of 62
~174 dihydric or higher alcohols, such as ethylene glycol, diethylene glycol, propylene gelylcol, dipropylene glycol, butanediol,
Examples include neopentyl glycol, bentanediol, hexamethylene diol, trimethylene glycol, heptanediol, octanediol, nonanediol, decanediol, etc. In addition to this dihydric alcohol, glycerin, trimethylolpropane, pentaerythritol, tris-2 -Contains trihydric or higher alcohols such as hydroxyisocyanurate.

The esterimide resin having a hydroxyl value of 110 to 300 used in the present invention is produced, for example, by the following method.

The first method is to synthesize imide acid in advance by dehydrating and condensing the trimellitic anhydride and the diamine so that the anhydride group/NlI2 ratio is 1:1 at a temperature of 100 to 200°C. Polyhydric alcohol containing imidic acid and trivalent or higher polyhydric alcohol has a 011/C0OH ratio of 1.2.
-2.1, preferably in the range of 1.2-1.8, and the reaction is carried out at a temperature of 160-240°C for 10-15 hours.

In this case, unless the polyhydric alcohol contains at least 30 mol% of the total alcohol, the final high-molecular-weight water-based paint will not be obtained (1).

The second method is to first produce a polyester polyol by dehydrating and condensing an aromatic dicarboxylic acid or a derivative thereof and a polyhydric alcohol containing a trihydric or higher alcohol by a known method, and then add a glossy anhydrous trimerite to this polyester polyol. The acid and the diamine may be adjusted to the same blending ratio as in the first method and added at the same time, and the dehydration condensation reaction may be carried out at a temperature of 130 to 240°C for 3 to 8 hours, or alternatively, First, cyamine may be added to the polyester polyol, and then the limellitic acid anhydride may be added. In this case, an aromatic dicarboxylic acid or its derivative, an imidic acid consisting of trimellitic anhydride and a diamine, and a polyhydric alcohol OH/CO01-1 or CO0
Adjust so that the R ratio is 1.2 to 2.1.

In this case, as in the first method, unless the trihydric alcohol in the polyhydric alcohol accounts for 30 mol% or more of the total alcohol, the final high molecular weight water-soluble paint will not be obtained.

Examples of aromatic dicarboxylic acids used in this case include terephthalic acid, isophthalic acid, and derivatives thereof.

The third method is to adjust the blending ratio of the above trimellitic anhydride, the above diamine, the above aromatic dicarboxylic acid or its derivative, and a polyhydric alcohol containing 30 mol% of a trihydric or higher alcohol to the same blending ratio as in the above first method. It can also be obtained by charging these simultaneously into a reaction vessel and conducting a dehydration condensation reaction at a temperature of 100 to 300°C for 10 to 15 hours.

A viscous solution of esterimide resin can be obtained by the above-mentioned methods 1 to 3, but as a means to further increase the molecular weight, it is possible to obtain a viscous solution of esterimide resin using a pressure cuff of 00 to 740 II 1 m at 180 to 280°C.
Preferably, the reaction is carried out under a reduced pressure of 11 g.

That is, the imide acid used in the present invention may be formed as an imide acid in advance, or may be obtained by any reaction between trimellitic anhydride and noamine during the synthesis process.

The imidic acid used in the present invention has the following general formula: % formula % General formula (I) In this general formula (1), I( is Imidic acids represented by are particularly preferred.

The ester imide resin used in the present invention is particularly suitable for imide acid (R ) is most desirable.

In this case, the blending ratio of (A) is (1,5·-97 mol%, preferably 10% by mole, based on the total amount of (A) and (B))
−537 mol%, most preferably 50 = 97 mol%
It is preferable to adjust so that

This nocarboxylic acid and its derivatives have a molecular weight of 166 to 222, such as terephthalic acid,
Examples include isophthalic acid and derivatives thereof, and these may be used alone or in combination of two or more.

When synthesizing the esterimide resin described in -, a mixed solvent of water and an organic solvent compatible with water is used for this F34 resin, thereby lowering the melting point of the esterimide resin, thereby facilitating the subsequent reaction. It is preferable to allow the resin to melt, and this is particularly effective for 01 resins, which often contain imidic acid, that is, resins with high melting points.

The esterimide resin obtained in this way usually has an acid value of about 0 to 10 and a weight average molecular weight of usually 2000=4.
．． 0,000, the softening point -11= by the ring and ball method is 70 to 130℃, and the hydroxyl value is usually about 110.-300 (measured by the acetylation method), so even if it is neutralized with a base etc., it cannot be used as a water-soluble paint. Can not do it.

In the present invention, in order to make this water-insoluble esterimide resin water-soluble, this esterimide resin is modified by adding a polybasic acid having only one anhydride group in one molecule, and furthermore, this r- The most significant feature is that the additive is dissolved in water using a basic compound.

Polyhydric carboxylic acids that do not contain an anhydride group in one molecule, or polycarboxylic acids that contain two or more anhydride groups in one molecule, have almost no reactivity of the carboxyl group or anhydride group. Since they are equal, a net-like (1η) structure occurs, leading to delification, and as a result, it is impossible to obtain a water-soluble coating.

The polybasic acids having only one acid anhydride group used in the present invention have a molecular weight of 70 to 216, such as 7-talic anhydride, /'% imic anhydride, methylhimic anhydride, Examples include succinic anhydride, hexahydrophthalic anhydride, maleic anhydride, itaconic anhydride, butanetetracarboxylic acid monoanhydride, etc.
Can be used alone or in combination with 2 or more L.

The addition reaction between the esterimide resin and the polybasic acid having only one anhydride group in the molecule is performed to add the polybasic acid to at least 20% of the number of hydroxyl groups in the esterimide resin. The temperature of this reaction system is in the range of 80 to 150°C, preferably 100 to 13°C.
The temperature is preferably in the range of 0°C, and the reaction is carried out at this temperature for 1 to 7 hours to add an acid anhydride to the terminal and/or side chain hydroxyl group and cleave it, thereby forming a high molecular weight imide group containing a carboxyl group. A containing polyester resin is obtained.

11-If the reaction temperature is less than 80°C, the high resin viscosity will deteriorate the reactivity, while if the temperature exceeds 130°C, the addition-cleaved anhydride will further react with the hydroxyl group to form a network or delta. undesirable.

In addition, if the viscosity of the reaction system is very high at this temperature and the reaction is difficult, an appropriate amount of the same solvent as used for esterimide resin synthesis may be used.

When water in which a basic compound is dissolved is added to the imide group-containing polyester resin obtained in this way, the carboxyl groups fixed in the resin are neutralized and a water-soluble paint is obtained.

In the obtained water-soluble insulating paint, basic compounds such as ammonia are sometimes volatilized during baking, and intramolecular and intermolecular crosslinking progresses to provide a film with excellent insulation and mechanical properties.

In the present invention, the basic compound added for the purpose of neutralizing the carboxyl group is a basic compound having a molecular position of 17 to 250, such as ammonia, aqueous ammonia,
Triethylalkylamine such as triethylamine, N
- N-alkyljetanolamines such as methylnoethanolamine, NφN-dialkylethanolamines such as N·N-trimethylethanolamine, and monoethanolamines, which may be used alone or in combination of two or more. can.

The basic compound should be added in an amount sufficient to neutralize the carboxyl groups in the carboxyl group-containing resin and thereby make the resin water-soluble. Approximately equal amounts of the basic compound may be added. However, volatile basic compounds such as ammonia and aqueous ammonia can
Since the excess can be removed by heating to around 0.degree. C., there is no problem even if a large amount is added.

In addition, the paint according to the present invention can provide a film with sufficiently good properties without using a catalyst or a crosslinking agent, but if desired, a water-soluble organometallic compound such as zinc acetate or a titanium chelate compound ( For example, titanium tetralactate), zirconium chelate compounds (for example, zirconium tetraacetylacetate) are preferably used, and other additives include water-soluble phenolic resin,
Addition of water-soluble compounds such as water-soluble epoxy resins, water-soluble amino resins, hexamethoxymethylated melamine, etc. may be effective.

(e) Effect The present invention involves adding a polybasic acid having only one anhydride group in the molecule to a high molecular weight esterimide resin with a hydroxyl value of 110 to 300, and adding this adduct to an esterimide resin with a basic compound in water. Therefore, it is not necessary to use expensive and harmful organic solvents, and since the esterimide resin has a high molecular weight, it can be applied to the object to be coated and baked to create an organic solvent-based imide resin. It has the ability to become a water-soluble insulating paint with various properties that can sufficiently compete with group-containing polyester insulating paints.

(f) Examples Hereinafter, the present invention will be explained in detail based on Examples, but the present invention is not limited thereto.

Example 1 Terephthalic acid 149,4. (0°9 mol), ethylene glycol 49.6B (0.8 mol), glycerin 4
6g (0.5 mol), dibutyltin dilaure) 0.08
g each, and heated while stirring.

When the temperature was raised to 180°C over 30 minutes, water was distilled out. Furthermore, the temperature was increased from 180°C to 230°C over 6 hours.
When heated to ℃ and reacted at this temperature for 3 hours, 32.
8 g of partially glycol-containing water distilled out.

Next, the inside of the reaction system was cooled to a temperature of 130°C, and 19.8 g (0.1 mol) of diaminodiphenylmethane and 38.4 g (0.2 mol) of trimellitic anhydride were added thereto.
The mixture was heated to a temperature of 220° C. over 1 hour and then reacted for 4 hours at a temperature of 220° C., and 7.2 g of reaction water was distilled out to obtain a brownish transparent resin.

This resin had an acid value of 12.8 and a softening point of 65°C.

This resin was reacted for 1 hour at a temperature of 220°C under a reduced pressure of 20 IAHg, to obtain an esterimide resin with an acid value of 4.2, a softening point of 90°C, and a hydroxyl value (measured by the acetylation method) of 165. .

Next, the inside of the reaction system was cooled to 120° C., 43.9 g of 7-talic anhydride was added, and the mixture was reacted for 2 hours to obtain a carboxyl group-containing imide-modified polyester resin.

The acid value of this If fat was 54.

Add 40% ammonia water (containing 28% ammonia) to this resin.
diluted with 120 g of water and added from the dropping funnel, and the temperature was 1.
After stirring at 00℃ for 30 minutes, the system becomes transparent and brownish in color.
Furthermore, add 380g of water, and the viscosity of the paint becomes 60 at a temperature of 30℃.
A water-soluble insulating paint of the present invention having a poise and non-volatile content of 35.2% by weight was obtained.

Example 2 Into the same apparatus as in Example 1, 124°5 g of terephthalic acid (
0.75 mol), ethylene glycol 53.32 g (0
, 86 mol), glycerin 39.56 bi(0°43 mol), butyltin dilaure) 0. When 18H and 33.2Fi (0.2 mol) of isophthalic acid were each charged and the same reaction as in Example 1 was carried out, 35 g of water partially containing glycol was distilled out.

Next, the inside of the reaction system was cooled to a temperature of 130°C, and the temperature of diaminodiphenylmethane was 9.9F! (0.05 mol), then 19.2 g (0.1 mol) of trimellitic anhydride was added, and 1
Reheat over time to a temperature of 220°C, then further heat to a temperature of 220°C.
When the reaction was carried out at °C for 4 hours, 3.6 g of reaction water was distilled out and a brown resin was obtained. This resin was heated to a temperature of 22
The reaction was carried out at 0°C for 1 hour under a reduced pressure of a pressure cuff of 20a+mHg to obtain an esterimide resin having an acid value of 3.6, a softening point of 92°C, and a hydroxyl value of 167.

Next, the inside of this reaction system was cooled to a temperature of 120° C., and 27.6 g of succinic anhydride was added and reacted for 2 hours to obtain a carboxyl group-containing imide-modified polyester resin 11.

The acid value of this resin was 57.

Add 3 ammonia water (containing 28% ammonia) to this resin.
When a diluted solution consisting of 6 g and 144 g of water is added from the dropping funnel and stirred for 30 minutes at a temperature of 100°C, the reaction system becomes brownish and transparent, and the viscosity of the paint is 70 voids at a temperature of 30°C, and the non-volatile content is 34.8% by weight. A water-soluble insulating coating of the present invention was obtained.

191 Example 3 Into the same apparatus as in Example 1, 149°4 g of terephthalic acid (0
, 9 mol), 221.9 g (0.85 mol) of tris-2-hydroxyethyl isocyanuride, and 17.4 g (0.28 mol) of ethylene glycol, and 0.075 Fi of dibutyltin dilaure were added. When the same reaction as in Example 1 was carried out, 32.6 g of reaction water partially containing glycol was distilled out.

Next, the inside of the reaction system was cooled to a temperature of 130°C, 19.8 g (0.1 mol) of diaminodiphenylmethane and 38.4 g (0.2 mol) of trimellitic anhydride were added, and the temperature was re-cooled to 220"C in 1 hour. When the mixture was heated and further reacted for 4 hours at a temperature of 220° C., 7.3 g of water partially containing glycol was distilled out, and a brown resin was obtained in the reaction system.

This resin was subjected to a reduced pressure reaction at a temperature of 220°C for 30 minutes under the reduced pressure of a pressure cuff of 20 IllmIIH, and the acid value was 2.8.
An esterimide resin having a softening point of 95° C. and a hydroxyl value of 128 was obtained.

Next, the inside of the reaction system was cooled to a temperature of 120° C., 70 g of hexahydrophthalic anhydride was added, and the reaction was carried out for 2 hours.

The acid value of the carboxyl-based imide modified polyester resin thus obtained was 53.

Add ammonia water (containing 28% ammonia) 6 to this resin.
A diluted solution consisting of 0g and 240g of water was added through the dropping funnel and stirred for 30 minutes at a temperature of 100°C, and the reaction system became transparent and brownish.Additionally, 510g of water was added, and the viscosity of the paint became 45 poise at a temperature of 30°C. A water-soluble insulating coating material of the present invention having a non-volatile content of 36.7% by weight was obtained.

Example 4 Terephthalic acid 1668 was added to the same 2p apparatus as in Example 1.
(1.0 mol), ethylene glycol 52°7g ((1
, 85 mol), 240.1 g (0.92 mol) of tris-2-hydroxyethyl isocyanurate, and 0.08 g of dibutyltin dilaurate were each charged and heated while stirring, and the temperature was raised to 180°C over 30 minutes. Then, we observed distillation of reaction water.

Further, Jf+ was dried up to 230° C. over 5 hours, and when the reaction was carried out at this temperature for 2 hours, 32.4 g of reaction water was distilled out.

Next, 152B of N-methyl-2-pyrrolidone was added, and the reaction system was cooled to a temperature of 131'C. 70 mol) was added and reheated to a pale yellow solid at a temperature of 1 B (1'C), and stirring was stopped for 11 minutes.

When heated further, the solution gradually came out from the surroundings, stirred again, heated to 220°C in 1 hour, and further reacted at this temperature for 5 hours.
29.2 g of water containing -methyl-2-pyrrolidone was distilled out to obtain a brownish transparent esterimide 431 fat.

This product has an acid value of 2.8, a softening point of 77°C, and a hydroxyl value of 16.
0 (because this resin contains N-methyl-2-pyrrolidone, the value of the resin dried at a temperature of 1110'C for 2 hours to scatter N-methyl-2-pyrrolidone).

Next, the inside of the reaction system was cooled to a temperature of 120°C, and 88% of succinic anhydride was added thereto. was added and reacted for 2 hours to obtain a carboxyl group-containing esterimide resin with an acid value of 71.

Add this resin to ammonia water (containing 28% ammonia) 11
Add 5 g and 345 g of water and stir for 30 minutes at a temperature of 100°C, it becomes brownish transparent.Additionally 215 g of water is added to make 200 g of an aqueous solution containing 3% titanium tetralactate.
was added to obtain a water-soluble insulating paint of the present invention having a viscosity of 68 poise at a temperature of 30°C and a non-volatile content of 40.1% by weight.

Example 5 N-methyl-2-pyrrolidone 9 was added to the same apparatus as in Example 1.
6.1 g of tris-2-hydroxyisocyanurate (0°4 mol) and 24.0 g of ethylene glycol were added while stirring. a, , (o, 4 moles), 4.4
99°0B (0.5 mol) of '-noaminodiphenylmethane, 192 g (1°0 mol) of trimellitic anhydride, and 0.04 g of dibutyltin dilaure were added and heated. When the temperature was raised to 150°C in 1 hour, the inside of the system became pale yellow paste, and the temperature further increased to 220°C.
It took 3 hours to heat up to ℃ and then the reaction proceeded for 2 hours at this temperature, the inside of the system turned brown and transparent and the reaction distillate was 3.
When 9g was distilled off, heating was stopped and the mixture was cooled.

The esterimide resin obtained here has a softening point of 82
℃, the acid value was 2.1, and the hydroxyl value excluding N-methyl-2-pyrrolidone was 140.

Next, the temperature inside the system was raised to 120°C, and 56.7% of 7-talic anhydride was added.
When the reaction was carried out for 2 hours, a carboxyl group-containing esterimide resin having an acid value of 39.0 was obtained. This OI
A mixture of 49 g of ammonia water (containing 28% ammonia) and 150 g of water was added to the fat through a dropping funnel, and the temperature was 100°C.
After stirring for 30 minutes, the reaction system became brown and transparent, and 365 g of water was further added to obtain the water-soluble insulating paint of the present invention, which had a viscosity of 38 voids at a temperature of 30°C and a non-volatile content of 39.6% by weight. .

Example 6 450 g of N-methylpyrrolidone was charged into a 117 flask equipped with a stirring device, a reaction water constant acid meter 1/1 cooling tube, and a thermometer, and without stirring, 150 g of 4,4゛-diaminodiphenyl ether (fi water) was added. When 288g of limellitic acid was charged and heated to a temperature of 150°C over 2 hours,
Distillation of reaction water was observed, and it took 2 hours to further heat to 200°C, and when heating was continued at this temperature for 2 hours,
57 g of distillate were obtained.

Next, the inside of the system was cooled to a temperature of 100° C. or less, and the contents were poured into a large excess of water to obtain a pale yellow precipitate. When the precipitate was washed with water three times and dried, an imidic acid having an acid value of 438 was obtained.

Then, in the same apparatus as in Example 1, 149.4% of terephthalic acid was added.
g (0,9 mol), ethylene glycol 49.6 g (0
, 8 mol), glycerin 46 g (0.5 mol), imidic acid 44. 0.08 g of a, (o, 1 mol) and dibutyltin dilaurate were each charged with stirring and heated.

Water was distilled out when the temperature was raised to 180°C over 30 minutes.

Furthermore, the temperature was raised to 220℃ for 6 hours (¥1 temperature [7,
If the reaction was continued for 3 hours at that temperature, it would be: 36°8
Part 8 of the water or distillate used to collect Grifur.

This at fat had a softening point of 67°C and an acid value of 11°8.

This resin was heated at a temperature of 22 (1'C with a pressure cuff of 20 m+n
The reaction was carried out for 1 hour under reduced pressure of TBI, and esterimide f,4(
Fat is 911.

The reaction system was then cooled to a temperature of i 2 n 'C 17, and 7 tarnic anhydride 44. g was added and reacted for 2 hours to obtain a carboxyl group-containing imide-modified polyester resin.

The acid value of this resin was 56.

This 11 fat and ammonia water (containing 28% ammonia) 4
A mixture of 0g and 120g of water was added from the dropping funnel and stirred for 30 minutes at a temperature of 100°C.The color became brownish-brown and transparent.Additionally, 38g of water (1) was added and the viscosity of 1 was 57voices at a temperature of 30°C. A water-soluble insulating coating material of the present invention having a non-volatile content of 36.1% by weight was obtained.

Water) fI insulating paint obtained in Example 1-6 and a general-purpose organic solvent type polyester paint as a comparative example
Using a flat type furnace, temperature: 450°C, take-up speed: 5.
The characteristics of the electric wire baked at 51 fl/min were as shown in Table 1.

Note that the characteristic test was conducted according to JIS C3210.

(The following is a blank space) From Table 1, it is recognized that the water-soluble insulating paint of the present invention has various properties that are comparable to those of the comparative examples.

(g) Effects of the Invention As stated in 2, the water-soluble insulating paint of the present invention is inexpensive because it uses water as a medium, and does not pollute the atmosphere by scattering solvents or toxic gases during baking. The work environment is also good as there is no risk of fire or explosion.

Furthermore, the baked-on film obtained by the water-soluble insulating paint of the present invention is comparable in electrical, mechanical, and thermal properties to conventional organic solvent-based paints, and is therefore suitable for electric wires, flexible prints, etc. Insulating materials such as substrates, vehicles,
It can also be applied to coatings on transportation vehicles such as ships and aircraft, building materials, and home appliances such as refrigerators and washing machines.

Claims (4)

[Claims] (1) A water-soluble product obtained by adding a polybasic acid containing only one anhydride group per molecule to an esterimide resin with a hydroxyl value of 110 to 300, and dissolving this adduct in water with a basic compound. Insulating paint. (2) The ester imide resin contains an imide acid containing an imide group consisting of trimellitic anhydride and a diamine, and a polyhydric alcohol containing a trihydric or higher polyhydric alcohol, and a carboxyl group 1.
The water-soluble insulating paint according to claim 1, which is reacted at a ratio of 1.2 to 2.1 equivalents. (3) The ester imide resin contains an aromatic dicarboxylic acid and its derivatives, an imide acid containing an imide group consisting of trimellitic anhydride and a diamine, and a polyhydric alcohol containing a polyhydric alcohol of trihydric or higher valence to 1 equivalent of a carboxyl group. Against 1.
The water-soluble insulating paint according to claim 1, which is reacted in a proportion of 2 to 2.1 equivalents. (4) The water-soluble insulating paint according to any one of claims 1 to 3, wherein a polybasic acid is added to at least 20% of the hydroxyl groups in the esterimide resin.