WO2012130724A1 - Polyester or polyesterimide resins terminated with the cyclic imide of an aromatic tricarboxylic acid, and wire enamel compositions comprising them - Google Patents

Abstract

Polyester or polyesterimide resin obtainable by reacting a) at least one aliphatic or aromatic polyol, b) at least one aliphatic or aromatic polycarboxylic acid or an ester-forming derivative thereof, c) optionally an at least difunctional compound which contains imide groups and reacts with polyols and/or polycarboxylic acids to form ester groups, d) the cyclic imide of an aromatic tricarboxylic acid and a primary aromatic monoamine, wherein the compound containing imide groups can also be performed in situ during the reaction of components a), b), c) and d).

Description

 Polyester or polyesterimide resins terminated with the cyclic imide of an aromatic tricarboxylic acid, and wire-enamel compositions containing the same

The present invention relates to polyester or polyesterimide resins terminated with the cyclic imide of an aromatic tricarboxylic acid, as well as novel wire enamel compositions containing these polyester or polyesterimide resins, and to their use. The production of transformers, electric motors, generators and electrical measuring devices places ever higher demands on enamel-insulated copper and aluminum wires. During processing, the enameled wires are increasingly stretched, squeezed and twisted. Even during operation, the enameled wires are subject to vibration, compression and thermal stress. The wire enamel applied to the wire therefore has to meet many requirements simultaneously. It should have a high chemical and thermal resistance, a good adhesion to wires and a particularly good mechanical strength. When used in inverter-controlled electric motors, it must be insensitive to the partial discharge that occurs in order to prevent short circuits. To meet the ever higher material requirements, therefore, a continuous improvement of the material properties of the wire enamels used.

The wire enamels which are currently on the market are essentially solutions of the customary binders in organic solvents or solvent mixtures. Widely used are binders such as polyester, tris-2-hydroxyethyl isocyanurate (THEIC) -modified polyester resins, polyesterimide resins, THEIC-modified polyesterimide resins and polyurethane resins. The use of polyester resin and THEIC-modified polyester resin solutions as wire enamels is known, for example, from US Pat. Nos. 3,342,780, 3,249,578, EP 0 144 281 A1 and WO 93/12188 A1. In addition to polyester resins or THEIC-modified polyester resins and organic solvents, wire enamels often contain crosslinking agents, crosslinking catalysts and other additives and auxiliaries.

Polyesterimide resins and THEIC-modified polyesterimide resin solutions as wire enamels are known, for example, from DE-A 1 445 263, DE-A 1 495 100 and WO 91/07469 A1. Besides polyesterimide resins or THEIC-modified polyesterimide resins and organic solvents, these wire enamels often contain the same crosslinking agents, crosslinking catalysts and other additives and auxiliaries such as polyester-based wire enamels.

At impregnating, potting and coating compositions for electrical components high demands are placed on their thermal stability and heat resistance.

The object of the present invention is to provide polyester and polyesterimide wire enamels which have an improved property profile in comparison to previously used polyester and polyesterimide wire enamels. The copper wires coated with the polyester and polyesterimide wire enamels should have improved thermal, mechanical and electrical properties, in particular improved thermal stability, compared with the copper wires painted with conventional wire enamels.

The object is achieved by a polyester or polyesterimide resin obtainable by reacting a) at least one aliphatic or aromatic polyol,

b) at least one aliphatic or aromatic polycarboxylic acid or an ester-forming derivative thereof,

c) optionally an at least difunctional, containing imide groups

Compound containing polyols and / or polycarboxylic acids with formation of

Reacts ester groups,

d) the cyclic imide of an aromatic tricarboxylic acid and a primary aromatic monoamine, wherein the imide group-containing compound c) can also be formed in situ during the reaction of components a), b), c) and d).

The object is further achieved by containing a wire enamel composition

(A) 10 to 80% by weight of at least one polyester or polyesterimide resin according to the invention,

 (B) 20 to 90% by weight of a solvent or solvent mixture,

(C) 0 to 20 wt .-% of a phenol-formaldehyde or cresol-formaldehyde resin, (D) 0 to 5 wt .- ⁰ o of a catalyst, and

 (E) 0 to 2 wt .-% of one or more conventional additives and auxiliaries, wherein the sum of components (A) to (E) 100 wt .-% results. It has been found that the polyester or polyester imide resins modified with the cyclic imide of an aromatic tricarboxylic acid and a primary aromatic monoamine (component d) provide wire enamel compositions which are superior to wire enamel compositions based on corresponding unmodified polyester or polyester imide resins Have adhesion to copper wires. In addition, copper wires painted with the wire enamel according to the invention have improved thermal, electrical and mechanical properties compared to copper wires painted with conventional wire enamel.

The binder (A) used to prepare the wire enamel composition of the present invention is a polyester resin or polyesterimide resin.

The polyester resins and polyesterimide resins modified according to the invention with a cyclic imide of an aromatic tricarboxylic acid with a primary aromatic monoamine (component d)) are derived from known polyester and polyester imide resins, as described, for example, in US Pat. Nos. 3,342,780, 3,249,578, 4,081,427, US Pat. US 4,476,279, EP-A 0 144 281 and WO 91/07469.

Suitable polyols for the preparation of the polyester resins a) are aliphatic or aromatic polyols, and mixtures thereof. Suitable diols are, for example, ethylene glycol, 1,2- and 1,3-propanediol, 1,2-, 1,3- and 1,4-butanediol, 1,5-pentanediol, neopentyl glycol, diethylene glycol and triethylene glycol. Suitable triols are for example, glycerol, trimethylolethane, trimethylolpropane and THEIC. Preferred polyols are ethylene glycol, glycerol and THEIC, and mixtures thereof. Particularly preferred are ethylene glycol and THEIC, and mixtures thereof. For the preparation of polyester resins suitable polycarboxylic acids b) are aliphatic or aromatic polycarboxylic acids and their ester-forming derivatives, ie their anhydrides, carboxylic acid halides and alkyl esters, and mixtures thereof. Suitable dicarboxylic acids are, for example, oxalic acid, malonic acid, succinic acid, glutaric acid, adipic acid, phthalic acid, isophthalic acid, terephthalic acid, trimesic acid, naphthalene dicarboxylic acids, their anhydrides, if they exist, their carboxylic acid halides, and their C 1 -C ₈ -alkyl esters, such as methyl, Ethyl, propyl, butyl, amyl, hexyl and octyl esters. Suitable are both the monoalkyl esters, the dialkyl esters and mixtures thereof. Suitable tricarboxylic acids are, for example, citric acid and trimellitic acid, their anhydrides, carboxylic acid chlorides and alkyl esters. Suitable tetracarboxylic acids are, for example, pyromellitic acid and naphthalenetetracarboxylic acid, their anhydrides, carboxylic acid chlorides and alkyl esters. Preferred polycarboxylic acids are aromatic dicarboxylic acids such as phthalic acid, isophthalic acid and terephthalic acid, their anhydrides, if they exist, their carboxylic acid halides, and their Ci-C ₈ - alkyl esters such as methyl, ethyl, propyl, butyl, amyl, hexyl and octyl ester. Particularly preferred are dialkyl terephthalates such as dimethyl terephthalate, diethyl terephthalate and dipropyl terephthalate.

Suitable esterification catalysts for the preparation of the polyester resins are, for example, metal salts such as lead acetate, zinc acetate, organic titanates such as tetramethyl titanate, tetraethyl titanate, tetrapropyl titanate, tetrabutyl titanate, tetraamyl titanate, tetrahexyl titanate, or organic acids such as p-toluenesulfonic acid. Preferred are organic titanates such as tetramethyl titanate, tetraethyl titanate, tetrapropyl titanate, tetrabutyl titanate, tetra-amyl titanate and tetrahexyl titanate. Particularly preferred is tetrabutyl titanate.

The preparation of the polyesterimide resins is carried out in a known manner by esterification of polycarboxylic acids with polyols in the presence of imide-containing compounds, esterification catalysts and optionally hydroxycarboxylic acids. Instead of the compounds containing imide groups, it is also possible to use compounds from which compounds which contain imide groups are formed during the esterification. In principle, the same polycarboxylic acids, polyols and esterification catalysts which are also suitable for the preparation of the polyester resins described above are suitable for the preparation of the polyesterimide resins. Polyesterimide resins are polyester resins in the broader sense, but contain chain-bound bound imidgruppenhaltige building blocks. These are reacted with esterification of the polyols with the polycarboxylic acids or formed during the esterification and incorporated into the polyester chain. Preferred polycarboxylic acids are aromatic dicarboxylic acids whose anhydrides, if they exist, their carboxylic acid halides, and their lower alkyl esters, especially their Ci-C4-alkyl esters. Particularly preferred are dialkyl terephthalates such as dimethyl terephthalate, diethyl terephthalate and dipropyl terephthalate. Preferred polyols are ethylene glycol, glycerol and THEIC and mixtures thereof. Particularly preferred are ethylene glycol and THEIC and mixtures thereof. In one embodiment of the invention, component b) contains THEIC. In a preferred embodiment of the invention, component b) contains THEIC and ethylene glycol.

The imide group-containing compounds c) which are reacted with or formed during the esterification in the esterification, for example, by reaction of cyclic carboxylic anhydrides having at least one further functional group, with primary amines which have at least one further functional group prior to the esterification reaction getting produced. Suitable cyclic carboxylic anhydrides having at least one further functional group are, for example, pyromellitic dianhydride, trimellitic anhydride and naphthalenetetracarboxylic dianhydride. Preferred is trimellitic anhydride.

Suitable primary amines having at least one further functional group are preferably diprimary diamines such as ethylenediamine, tetramethylenediamine, hexamethylenediamine, nonamethylenediamine, benzidine, diaminodiphenylmethane, diaminodiphenyl ketone, sulfone, sulfoxide, ethers and thioethers, phenylenediamine, toluenediamine, xylylenediamine, amino alcohols such as monoethanolamine, Monopropanolamines, as well as aminocarboxylic acids such as glycine, aminopropionic acid, aminocaproic acid and aminobenzoic acid. Preferred are diprimary diamines such as ethylenediamine, tetramethylenediamine, hexamethylenediamine, nonamethylenediamine, benzidine and Diaminodiphenylmethane. Particularly preferred is diaminodiphenylmethane (methylene dianiline).

Preferred imide group-containing compounds are reaction products of trimellitic anhydride and diprimary diamines.

Diprimary diamines can be reacted with tricarboxylic acid anhydrides in a molar ratio of 1: 2. For example, imide group-containing compounds c) can be obtained by reacting 2 mol of trimellitic anhydride with 1 mol of said diprimary diamines.

As the amino group-containing compounds having another functional group, amino alcohols are suitable, e.g. Monoethanolamine and monopropanolamines, furthermore aminocarboxylic acids such as glycine, aminopropanoic acid, aminocaproic acids or aminobenzoic acids. These can be reacted, for example, with tricarboxylic anhydrides in a molar ratio of 1: 1 or with tetracarboxylic dianhydrides in a molar ratio of 2: 1.

For example, imide groups may also be introduced into the polymer chain by reaction with compounds obtainable by reaction of 1 mole of pyromellitic dianhydride and 2 moles of said amino alcohols or aminocarboxylic acids.

For example, imide groups may also be introduced into the polymer chain by reaction with compounds obtainable by reacting 1 mole of trimellitic anhydride with 1 mole of said aminocarboxylic acids.

Instead of the imide group-containing compounds whose preparation takes place before the esterification reaction, the cyclic carboxylic anhydrides listed with at least one further functional group and primary amines having at least one further functional group can be used directly in the esterification reaction in the preparation of polyesterimide resins. In one embodiment, the cyclic carboxylic acid anhydrides having at least one further functional group and the primary amines having at least one further functional group are used directly in the esterification reaction. The polyester resin or polyesterimide resin is modified according to the invention by reacting as component d) the cyclic imide of an aromatic tricarboxylic acid and a primary aromatic monoamine, whereby aromatically substituted imide groups are introduced at the polymer chain end.

The cyclic imide of the aromatic tricarboxylic acid can be obtained by reacting the anhydride of the aromatic tricarboxylic acid or else by reacting the aromatic tricarboxylic acid itself with an aromatic monoamine. Preferred aromatic tricarboxylic anhydride is trimellitic anhydride. Suitable primary aromatic amines are aniline, naphthylamine, 2-aminopyridine, 3-aminopyridine and 4-aminopyridine. Aniline is preferred.

The cyclic imide of trimellitic acid or trimellitic acid anhydride and aniline (N-phenyl trimellitic acid imide) is particularly preferred.

In general, component d) is used in amounts of 0.5 to 10% by weight, preferably 1 to 5% by weight, in particular 2 to 4% by weight, based on the amount of components a) to d).

The inventively modified polyester or polyester imide resins are in the wire enamel composition according to the invention usually in amounts of 10 to 80 wt .-%, preferably 25 to 60 wt .-%, particularly preferably from 30 to 55 wt .-%, based on the sum the components (A) to (E) used.

The solvent (B) used in the wire enamel according to the invention is the customary wire enamel solvent and mixtures thereof. These are usually added as an extender aromatic hydrocarbons and mixtures of aromatic hydrocarbons. Examples of suitable wire-coating solvents are aromatic alcohols such as phenol, cresol and xylenol, glycol ethers such as butylglycol, methyldiglycol, ethyldiglycol, butyldiglycol and phenylglycol, esters such as methyl benzoate, dimethyl succinate, dimethyl glutarate, dimethyl adipamide and N, N-dimethylacetamide, cyclic ketones such as cyclohexanone and Isophorone, cyclic carbonates such as propylene carbonate, lactones such as γ-butyrolactone and lactams such as N-methylpyrrolidone. Suitable diluents are, for example, aromatic hydrocarbons, such as xylene, Toluene, ethylbenzene and cumene, and mixtures of aromatic hydrocarbons such as solvent naphtha and heavy benzene. Preferably used are mixtures of aromatic alcohols such as phenol, cresol and xylenol with aromatic hydrocarbons such as xylene, toluene, ethylbenzene and cumene or mixtures of aromatic hydrocarbons such as solvent naphtha and heavy benzene, optionally with lactams such as N-methylpyrrolidone. Particularly preferred is a mixture of cresol, xylenol and solvent naphtha.

The solvents are in the wire-enamel composition of the invention usually in amounts of from 20 to 90 wt .-%, preferably from 30 to 75 wt .-%, particularly preferably from 55 to 65 wt.%, Based on the sum of the components (A) to (E), used.

As component (C) up to 20 wt .-% of a phenol-formaldehyde or cresol-formaldehyde resin can be used with. If a phenol-formaldehyde or cresol-formaldehyde resin is reacted with, then in amounts of generally 1 to 10 wt .-%, preferably 2 to 7 wt .-% based on the amount of components (A) to (E).

Catalysts (D) which are suitable for the preparation of the wire enamel according to the invention are, for example, metal salts such as lead acetate, zinc acetate, organic titanates such as tetramethyl titanate, tetraethyl titanate, tetrapropyl titanate, tetrabutyl titanate, tetra-amyl titanate, tetrahexyl titanate or organic acids such as p-toluenesulfonic acid. Preferred are organic titanates such as tetramethyl titanate, tetraethyl titanate, tetrapropyl titanate, tetrabutyl titanate, tetra-amyl titanate and tetrahexyl titanate. Particularly preferred is tetrabutyl titanate.

The catalyst is in the wire enamel composition according to the invention usually in amounts of 0 to 5 wt .-%, preferably from 0.2 to 4 wt .-%, particularly preferably from 0.5 to 3 wt.%, Based on the sum of Components (A) to (E) used.

The wire enamel according to the invention may contain one or more customary additives and auxiliaries (E). For example, conventional leveling agents based on polyacrylates and polysiloxanes can be used as additives and auxiliaries for wire enamels. The additives and auxiliaries are in the wire-enamel composition according to the invention usually in amounts of 0 to 2 wt .-%, preferably from 0 to 1.0 wt .-%, particularly preferably from 0 wt.% To 0.5 wt.%, based on the sum of components (A) to (E) used.

The wire enamels are produced by the usual methods.

The wire enamel compositions of the invention can be used to coat copper and aluminum wires. In particular, they can be used for coating copper wires.

The wire enamels according to the invention are applied to the copper wire by conventional wire-coating machines and cured. The paint film thickness required in each case is built up by at least 1 to 15 individual jobs, each individual paint job is cured bubble-free before the new paint job. Conventional wire-coating machines operate at take-off speeds of 5 to 180 m / min, depending on the thickness of the wire to be coated. Typical oven temperatures are between 300 ° C and 700 ° C. The painted wires are tested according to IEC 60851. The invention is further illustrated by the following examples. Examples

Example 1 Preparation of monoimide compound

A 5 liter flask is charged with the following ingredients:

186.0 g aniline

384.0 g of trimellitic anhydride

1150.0 g of cresol

1150.0 g solvent naphtha

The reaction mixture is slowly heated to the reaction temperature of 160 to 180 ° C with stirring and simultaneous removal of water using a capacitor within 2.5 hours. 36 g of water of reaction are removed. The reaction mixture is then cooled to room temperature. The pale yellow precipitate The monoimide compound is filtered off and dried at 120 to 150 ° C for 6 hours. The resulting monoimide compound has a melting point of about 260 ° C and an acid value of about 210 mg KOH / g, corresponding to the theoretical value of 210.1 1 mg KOH / g.

Example 2 Preparation of a cresol-formaldehyde resin

The preparation of the cresol-formaldehyde resin is carried out according to US 4,206,098, Example 2, Part IV.

A 3 liter flask is charged with the following ingredients:

1376.0 g of meta / para-cresol

605.0 g of formaldehyde (40%)

23.4 g of triethanolamine

The reaction mixture is heated under constant stirring for 1.5 hours under reflux and then cooled to 55 ° C. In a Scheidetrichtet the organic phase is separated from the aqueous phase. The organic phase is transferred to a flask, mixed with 21.7 g of salicylic acid and heated at a pressure of 26 mm Hg at 40 ° C to 80 ° C until a viscosity of 36 poise is reached. Then, 1695 g of cresol are added, whereby a solution is obtained, the content of low volatility components is 30 wt .-%. Example 3 (comparative example)

For comparison purposes, a polyester wire enamel according to US Pat. No. 3,313,781, Example 1, is produced. A mixture containing 193.2 g of ethylene glycol, 140.0 g of cresol, 917.0 g of dimethyl terephthalate, 193.2 g of glycerol and 3.57 g of cerium naphthanate (6%) is heated to 220 ° C, wherein a polyester resin with a OH number of 180 to 220 mg KOH / g is obtained. The polyester resin is cooled to 150 to 180 ° C and diluted with 420.0 g of cresol and 650.0 g of xylenol. After cooling to room temperature, 650 g of solvent naphtha, 15.75 g of butyl titanate and 2.60 g of p-toluenesulfonic acid are added. It will be 1 more Led for an hour. The final product is then filtered and the viscosity and solids content are determined.

Viscosity (according to DIN 53211 / Cup 4 mm, at 23 ° C): 100 sec.

Solids content (1 g, 1 h, 180 ° C): 35.0%

Example 4

The polyester wire enamel is prepared as described in Example 3, but 39.2 g of the monoimide compound prepared according to Example 1 are additionally mixed with dimethyl terephthalate and the other ingredients. The monoimide-modified polyester resin is thus produced from the following ingredients:

Viscosity of the obtained wire enamel (according to DIN 53211 / cup 4 mm, at 23 ° C.): 108 sec. Solids content (1 g, 1 h, 180 ° C.): 34.5%

With the polyester wire enamel prepared according to Examples 3 and 4, copper wires with a diameter of 1.0 mm are painted with a standard wire-coating machine under the following painting conditions: Oven: MAG VE6

 Temperature: 450 ° C

Application system: nozzles

Number of passes: 8

Discharge speed: 15 m / min

Diameter increase: 65 to 75 μιη

The painted wires are tested according to IEC 60851. The results are summarized in Table 1.

Table 1

As can be seen from the data in Table 1, the wire enamel compositions based on the inventive monoimide-modified polyesters according to Example 4 show a very good adhesion during winding and an excellent surface quality. Further, the wire coated with the wire-enamel composition of Example 4 of the present invention exhibits a significant increase in thermal shock resistance and heat pressure as compared with a wire coated with a conventional polyester based wire enamel composition. The tan delta- steep increase of the coated wire according to the invention is higher than that of the comparative example. The values of the wires coated according to the invention correspond to the specification according to IEC 60851 for polyester of class 130.

Example 5 (Comparative Example)

For comparison purposes, a wire enamel based on a THEIC-modified polyester according to US 5,854,334, Example 4, prepared. A mixture containing 55.24 g of ethylene glycol, 30.08 g of cresol, 206.2 g of dimethyl terephthalate, 122.03 g of THEIC and 0.32 g of butyl titanate is heated to 210 ° C to obtain a polyester resin having an OH number of 140 to 260 mg KOH / g produce. The THEIC-modified polyester resin is diluted at 150 ° C to 180 ° C with 306.07 g of cresol and 111.26 g of xylenol. After cooling to room temperature, 107.03 g of solvent naphtha, 20.0 g of butyl titanate and 41.77 g of the cresol / formaldehyde resin prepared according to Example 2 are added. It is stirred for another 1 hour. The final product is then filtered and viscosity and solids contents are determined. Viscosity of the obtained wire enamel (23 ° C): 530 mPas

Solids content (1 g, 1 h, 180 ° C): 39.0%

Example 6 A THEIC-modified polyester wire enamel is prepared as described in Example 5, except that an additional 12.0 g of the monoimide compound of Example 1 are mixed with dimethyl terephthalate and the other ingredients. Thus, the wire enamel based on the monoimide-modified, THEIC-modified polyester resin is prepared from the following ingredients:

Viscosity of the wire enamel obtained (23 ° C): 560 mPas

Solids content (1 g, 1 h, 180 ° C): 38.4% With the wire enamel compositions according to Examples 5 and 6, 1.0 mm copper wire is painted as described in Example 4, but the take-off speed is 19 m / min. The painted wires are tested according to IS 13778 / IEC 60851. The results are summarized in Table 2.

Table 2

As can be seen from the data from Table 2, the wire enamel according to Example 6 has a significantly improved adhesion during winding compared to the comparative example. In addition, the coated wire according to Example 6 shows a significantly increased thermal shock resistance of 220 ° C. The thermal pressure and the tan delta slope are increased compared to conventional THEIC-modified polyesters. The level of wire values are in accordance with IS 13778 / IEC 60851 specifications for Class 155 wires coated with THEIC modified polyesters.

Example 7 (comparative example)

For comparison purposes, a wire enamel based on a THEIC-modified polyestersimide according to US 4,267,231, Comparative Example 2A, is prepared.

93.0 g of ethylene glycol, 301.2 g of THEIC, 220.5 g of terephthalic acid, 221.6 g of trimellitic anhydride, 114.2 g of methyl endianiline, 210.5 g of diethylene glycol monobutyl ether and 0.34 g of tetraisopropyl titanate are obtained in a one-pot process 225 ° C to produce a polyesterimide resin. This gives 89.3 g of distillate. At 180 ° C., the batch is diluted with 632.0 g of diethylene glycol monomethyl ether and 211.0 g of Solvesso 100. After cooling the mixture, 19.4 g of tetraisopropyl titanate as Catalyst was added and stirred for 1 hour. The final product is filtered and the viscosity and solids content are determined.

Viscosity of the wire enamel obtained (23 ° C): 203 mPas

Solids content (1 g, 1 h, 180 ° C): 42.60%

Example 8

A wire enamel based on THEIC-modified polyester imide is prepared as described in Example 7, but an additional 29.4 g of the monoimide compound of Example 1 are mixed together with terephthalic acid and the other ingredients. Thus, the wire enamel based on the monoimide-modified, THEIC-modified polyesterimide resin is prepared from the following ingredients:

Viscosity of the wire enamel (23 ° C): 208 mPas

Solids content (1 g, 1 h, 180 ° C): 42.5%

With the wire enamels prepared according to Examples 7 and 8, 1.0 mm copper wire is painted as in Example 4. The take-off speed is 15 m / min.

The painted wires are tested according to IS 13778 / IEC 60851. The results are summarized in Table 3. Properties Example 7 Example 8

Smooth surface smooth

 Winding liability, 1 x d + pre-stretch 10% 15%

 Breakdown voltage at room temperature 9.2 kV 9.8 kV

 Heat shock, 2.24 mm D, 30 min 200 ° C, lxd 210 ° C, lxd

 Heat pressure, 2 min. 340 ° C 390 ° C

 Tan delta 149 ° C 160 ° C

As the data of Table 3 show, the wire coated according to the invention with the wire enamel according to Example 8 shows a significant increase in the breakdown voltage at room temperature, the heat pressure and the tan delta steep increase, compared with a wire coating based on a conventional THEIC-modified polyester imide coated wire. The level of wire values is in accordance with IEC 60851 specification for THEIC modified polyesterimide coated wire of class 180. As the results of Tables 1 to 3 show, the concomitant use of 3% by weight of the monoimide compound of Example 1 a significant improvement in adhesion, thermal shock, thermal pressure and the tan delta steep increase in painted wires of the classes 130, 155 and 180. With the concomitant use of 1 to 3 wt .-% of the monoimide compound so significantly improved thermal values in painted wires of Classes 130, 155 and 180 can be achieved.

Claims

claims Polyester or polyesterimide resin, obtainable by reaction of  a) at least one aliphatic or aromatic polyol,  b) at least one aliphatic or aromatic polycarboxylic acid or an ester-forming derivative thereof,  c) optionally an at least difunctional, imide-containing compound which reacts with polyols and / or polycarboxylic acids to form ester groups,  d) the cyclic imide of an aromatic tricarboxylic acid and a primary aromatic monoamine, wherein the imide-containing compound can also be formed in situ during the reaction of the components a), b), c) and d). Polyester or polyesterimide resin according to claim 1, characterized in that component a) contains tris (2-hydroxyethyl) isocyanurate. Polyester or polyesterimide resin according to claim 1 or 2, characterized in that component a) contains ethylene glycol. Polyester or polyester imide resin according to one of claims 1 to 3, characterized in that component b) contains terephthalic acid or a dialkyl terephthalate. Polyester or polyester imide resin according to one of claims 1 to 4, characterized in that component c) is the reaction product of trimellitic anhydride with an aromatic or aliphatic diamine. 6. polyester or polyester imide resin according to claim 5, characterized in that the diamine is diaminodiphenylmethane. Polyester or polyesterimide resin according to one of claims 1 to 6, characterized in that component d) is the cyclic imide of trimellitic acid and aniline. Polyester or polyesterimide resin according to any one of claims 1 to 7, characterized in that the component d) in an amount of 0.5 to 10 wt .-%, based on the sum of components a) to d), is reacted. Use of a polyester or polyesterimide resin according to any one of claims 1 to 8 for the preparation of wire enamel compositions. Containing wire enamel composition  (A) 10 to 80% by weight of at least one polyester or polyesterimide resin according to one of claims 1 to 8,  (B) 20 to 90% by weight of a solvent or solvent mixture, (C) 0 to 20% by weight of a phenol-formaldehyde or cresol-formaldehyde resin,  (D) 0 to 5 wt .-% of a catalyst, and  (E) 0 to 2 wt .-% of one or more conventional additives and auxiliaries, wherein the sum of components (A) to (E) 100 wt .-% results. Wire enamel composition according to claim 10, characterized in that it contains 1 to 10 parts by weight of component (C). Use of the wire enamel composition according to claim 10 or 11 for the coating of electrical and electronic components and devices. Use according to claim 12 for coating copper wires.