DE1494454C2 - Highly heat-resistant coatings provide electrical insulating varnish - Google Patents

Description

The subject of patent 14 94 452.6-43 is an electrical insulating varnish which provides highly heat-resistant coatings based on the reaction products of aromatic polycarboxylic acids, bi- and / or higher functional alcohols and diamines in organic paint solvents, characterized in that it contains reaction products which have been produced by condensation from

10 equivalents of bifunctional and / or higher functional aromatic carboxylic acids, their anhydrides and / or 5 to 16 equivalents of bi- and / or higher-functional alcohols and

5.5 to 0.5 equivalents of diamines, with 10 equivalents of bifunctional compounds 4 to 20 equivalents of higher functional compounds are omitted.

The electrical insulating varnish described in the main patent preferably contains reaction products that are produced have been made by condensing 10 equivalents of bifunctional and / or higher functional aromatic Carboxylic acids, their anhydrides and / or esters,

7 to 10 equivalents of bifunctional and / or higher functional alcohols and

3 to 0.8 equivalents of diamines,

whereby for 10 equivalents of bifunctional compounds 6 to 15 equivalents of higher functional compounds omitted. .

It is also preferred that the condensation products in a 1: 2 solution in m-cresol at 25 ° C viscosities between 900 and 2000 cP, particularly preferably between 1400 and 1500 cP. Are expedient According to the main patent, the condensation products were produced by condensing terephthalic acid, Trimellitic acid and / or pyromellitic acid, ethylene glycol and / or neopentyl glycol, glycerol and / or trimethylolpropane and 4,4'-diaminodiphenylmethane.

The insulating coatings produced with the electrical insulating varnishes of the main patent have valuable electrical properties and mechanical properties. However, in some cases, when making the insulating coatings Difficulties arise. In particular when the proportion of condensed amino-containing compounds is relatively high, it can happen that the coatings with greater thicknesses a do not have perfectly smooth surfaces.

It has now been found that the coatings in this Relationship have improved characteristics if the

ίο conversion products in the presence of esters of the Titanic and / or zirconic acids in such proportions that on K) Og the reaction productc 0.05 up to 0.5 g, preferably 0.1 to 0.2 g of zirconium or titanium, have been produced.

The invention relates to the electrical insulating varnish defined in the claim.

The compounds described in the main office are used as starting materials for the production of polyester resins. It is particularly advantageous to incorporate diamine residues together with amino alcohol and / or amino acid, preferably aminobenzenecarboxylic acid such as p-aminobenzoic acid residues. Contain the polyester resins used according to the invention
in addition to the cine-condensed components described in the main patent, chemically bonded titanium and / or zirconium atoms. To produce the curable polyester resins used according to the invention, esters of titanium or zirconic acid, preferably butyl titanate, are reacted with the starting components described in the main patent or the polyester resin produced therefrom.

A transesterification occurs and the zirconium or titanium is condensed into the resin molecules. It can also other esters of zirconic or titanic acid, such as cresyl titanate, trioleyl butyl titanate, triethanolamine titanate, Cetyititanat, Tetra-n-Butylzlrkonat can be used.

The butyl titanate is particularly good as a commercial product accessible and is therefore preferred.

The method is expediently carried out in the following manner. First, as in the The main patent describes a resin produced from the starting materials specified in the main patent. This Resin is then expediently diluted with solvents, preferably cresol. Be used as a solvent preferably those used that are also used to prepare the impregnation solution. That is enough here Adding a small amount of the solvent, e.g. B. of 10% based on the resin solids content. To this Solution is then added to the ester of zirconic or titanic acid and the reaction mixture for a few minutes. z. B. about K) minutes, heated to elevated temperatures of preferably about 180 ° C.

The ester of zirconic or titanic acid can, however, also be added to the other reaction components at the beginning or during the production of the resin, as described in the main patent. The reaction conditions specified in the main patent are used. It is particularly advantageous to add the ester of zirconic or titanic acid to the second group of starting components given in the examples, which is expediently added in several portions to the reaction mixture from the first group of starting components.
It is known to add esters of titanium, preferably butyl titanate, as mixture components to the impregnation solutions in the process for producing coatings on electrical conductors (compare Example 2b). Surprisingly, better social

nisse achieved when, according to the method according to the invention, the titanium or zirconium in the polyester resin mixture is installed. The amount of titanium or zirconium in the impregnation solution can surprisingly be less than when the butyltilanate is added to the impregnation solution according to the known method and a conversion only occurs on the electrical conductor when the resin is burned in. Particularly beneficial the method of the invention is effective when using impregnating solutions, their polyester resins have or form a high proportion of imide groups, d. That is, the chemically built-in content has the effect Titanium or zirconium significantly improves the course of the paint.

Example '

Thermal shock 15 '200 ° C
15 '240 ° C

Detention number according to
VSM 23713

Thermoplasticity 90%

65-50%

20%

1.2 moles of dimethyl terephthalate 7 · moles of ethylene glycol
50 g cresol as an entrainer
1 g zinc acetate

233 g 434 g

20th

are heated until the theoretical amount of methanol has distilled off, which is reached between 220 and 240 ° C. Thereafter, the temperature is lowered to 120 to 14O ⁰ C and from 5 portions in a mixture

3 moles of trimellitic anhydride

1.1 moles of 4,4'-diaminodiphenyl methane

576g 218g

3 ^r )

40

added. After each partial addition, the temperature is increased again to about 180 ° to 200 ° C. until the reaction _{mixture has} become thinner. After the addition is complete, water is distilled off from the reaction mixture at temperatures up to about 260 ° C. until a clear resin The reaction product is then treated further in a water jet vacuum at about 160 to 180 ° C. until a viscosity of about 2000 cP 1: 2 in m-cresol is reached.

After adding 50 to 100 g of cresol at about 160 to 180 ° C, at around 180 ° C, 8 g of biilyl ttanate (monomeric) added with vigorous stirring. It is stirred for 10 minutes at this temperature, cooled and diluted to a 50% solution with cresol. The titanium content is then about 0.1% of the resin solids amount. This solution was converted into naphtha by adding Sol-ventnaphtha and small amounts of customary hardeners, leveling agents and crosslinkers (isocyanates) about 30% longer wire enamel produced. (In other experiments, about 25 to 35% wire enamels were produced.)

A copper wire was made with this solution on a horizontal wire enamelling machine using conventional methods coated with a diameter of 0.8 mm. At a take-off speed of 6 m per minute, 8 pulls, a length of the oven of 2.7 m and an oven temperature of 400 ° C was a paint layer of 62 up to 65 μ achieved. The following test values were determined:

1 X 0 no cracks

1 x 0 occasional cracking of 3 curls, 2 are crack-free 1 lock shows 1 tear

406

158 ° C

190-260 ° C

28O ⁰ C

Example 2a:

4.4 moles of ethylene glycol
0.6 moles of terephthalic acid
0.2 moles of isophthalic acid

Zinc acetate

Cresol

274 g 100 g

34 g 0.4 g

50 g

are esterified as much as possible by heating until the theoretical amount of water has distilled off. The temperature is increased up to about 200 ° C. Then the temperature is lowered to 150 ° C and in 6 servings of a mixture

3.2 moles of trimellitic anhydride, 1.2 moles of 4,4'-diaminodiphenyl methane 0.4 moles of p-aminobenzoic acid

added. After each partial addition, the temperature is increased again to about 200 ° C., with the reaction mixture becomes thinner. The reaction temperature is increased to before each additional portion is added about 150 to 175 ° C. After the last portion has been added, 50 g of cresol are added and the temperature is increased of the reaction mixture increased to about 260 ° C. The condensation is canceled if none further water separation takes place.

100 g of cresol are added to this resin melt, and 15 g of monomeric butyl titanate are then stirred in at 180.degree. This amount corresponds to about 3.6 g titanium dioxide or 2.1 g titanium. There will be another 10 minutes for this one Stirred temperature further, then cooled and further diluted with solvents. The content of titanium is about 0.17% of the resin solids. The production of the impregnation solution and the coating the electrical conductor is carried out as described in Example I.

Winding strength after
Pre-stretching

30%

Pre-stretching

Wrap around 1 X 0

Pencil hardness 2H

as delivered

Schabc / uhl after
HI-RBERTS works standard

WN 2009 (cf.
ETZ edition B issue 11,
1958 SW 17-423)

Example 2b

The procedure was as described in Example 2a, with the difference that butyl titanate does not condense became. As described in Example 1, the resin produced in this way was used to produce a wire enamel with a solids content produced by 31.5%. This varnish was pro ky Lacquer solution 23 g of a 33% solution of monomeric butyl titanate in cresol were added. The titanium content is! about 0.69b based on the amount of resin solids. A copper wire as in Example 1 was used for the enamel painted as described.

Example 2c

The resin was prepared as described in Example 2b, with the difference that the resin condensed more was by distilling off remaining amounts of water at 240 ° C. for an additional 10 hours at the end of the reaction and, in addition, excess ethylene glycol was vacuum removed in a water jet. The paint production took place as in example 1. The solids content is about 30%. The im Example 2b added amount of butyl titanate. The titanium content is then about 0.5'V, based on the Hurz solid-state quantity. A copper wire was coated with the paint as described in Example 1.

The values given in Tables 1 and 2 show that the coating obtained according to Example 2a with regard to its properties is superior to the coatings produced according to Comparative Examples 2b and 2c.

Table 1

Lacquer edition

Assessment of the coating

Example 2a 55 to 60 μ smooth

85 to 90 μ smooth

90 μ only a few fine bubbles

Example 2b 55 to 60 μ continuous course disorders

70 to 80 μ consistently severe progressive disorders

and vesicles in places

Example 2c 53 to 58 μ continuous course disorders

78 to 85 μ continuous course disorders

and vesicles in places

Table 2

Lacquer elasticity

Hardness Stick number Scraper number Braise test Remaining distance

Heat shock 1 XO

Example 2a tear wrap resistant 2 H 525

Example 2b 20%

Example 2c 15%

2 H 441

2 H 465

25th

12th

14.7 min 90% to 165 ° C. 300 ° C. 25% to 250 ° C. 6% to 300 ° C. 13.5 min 90% to 160 ° C. 240 ° C. 15% to 250 ° C. 14.4 min 90% to 165 ° C. 240 ° C. 44% to 250 ° C. 10% to 300 ° C.

Example 3

1 mole of dimethyl terephthalate
6 moles of ethylene glycol
Rosol 50 g as an entrainer
Zinc acetate 1 g

192 g

372 g resin solids. The preparation of the impregnation solution and the coating on the electrical conductor is carried out as described in Example 1. The paint finish is 58 to 60 μ. The following test values were determined:

are heated as described in Example 1 until the theoretical amount of methanol is distilled off, what between 220 and 240 ° C is reached. The temperature is then lowered to 120 to 140 ° C. and In 4 is the same Servings a mix of

3 moles of trimellitic anhydride

1 mole of 4,4'-diaminodiphenyl methane

576g 218g

60

added as described in Example 1. Before the third portion is added, 8 g of monomeric butyl titanate are added undiluted or diluted with a small amount of cresol. After stirring for about 10 minutes, the third and fourth portions are added as usual. Further processing is carried out as described in Example 1. The titanate content is about 0.1% of the winding strength after 30%
Pre-stretching

Pencil hardness 2H

as delivered

Cockroach number after 23

HERBERTS works standard

WN 2009

Detention number according to 432

VSM 23713

Breakdown voltage 3880 V

Pre-stretching

Wrap around 1 X 0

7th

Heat shock 15 '200 ° C 1 X 0 of 3 curls

2 are free of cracks 1 curl shows 1 crack

15 '240 ° C 1 X 0 of these curls 2 are free of cracks 1 lock shows 1 tear

Example 4

10

The procedure is as described in Example 1, with the difference that instead of the 8 g of butyltilanate, 12 g of a tetra-n-butylzirconium solution, about 30% 1 g in butanol, were added. The zirconium switch is about 0.1 ¹ V. of the resin solids amount. A paint application of 43 to 53 μ was obtained. The following test values were determined:

Winding strength after
Pre-stretching 30% Pre-stretching
Wrap around 1 X 0 1.0.0, 5: 278 G 20th Pencil hardness
in the delivery country 2H 100 G Cockroach number after
HERBERTS works standard
WN 2009 17th 34 G 25th Breakdown voltage 3960 V O,: > g Thermal shock 15'200 ° C i. O. 50 G 30th 15'240 ° C 1 XO B e s t ) iel 4.48 moles of ethylene glycol 35 0.6 moles of terephthalic acid 0.2 moles of isophthalic acid Zinc acetate Cresol 40

are esterified as much as possible by heating until the theoretical amount of water has distilled off. the The temperature is increased to 200 ° C. The temperature is then lowered to 150 ° C. and in six Servings a mix of

2.92 moles of trimellitic anhydride 560 g

1.12 moles of 4,4'-diaminodiphenylmethane 222 g

added. The temperatures when adding each Portions are increased as follows:

1st serving: from 155 to 205 "C

2nd serving: from 160 to 210 "C

3rd serving: from 170 to 215 "C

4th serving: from 175 to 225 "C

5. Serving: from 185 to 260 "C

After the last partial amount has been added, the melt is kept at 250 ° C. until no more water is distilled off. After cooling to 220 ° C., 200 g of cresol are stirred in. Then 7.5 g of monomeric butyl titanate are added and the temperature is kept at 180 ° C. for 120 minutes. The titanium content is about 0.15% TiO ₂ or about 0.09% titanium of the resin solids.

65

Claims (1)

Claim: Highly heat-resistant coatings providing electrical insulating lacquer based on the reaction products of aromatic polycarboxylic acids, bi- and / or higher-functional alcohols and diamines in organic lacquer solvents, which contains reaction products that have been produced by condensing 10 equivalents of trifunctional and / or higher-functional aromatic carboxylic acids, optionally in a mixture with bifunctional aromatic carboxylic acids, their anhydrides and / or esters, 5 to 16 equivalents of bifunctional and / or higher-functional alcohols and
5.5 to 0.5 equivalents of diamines, with 4 to 20 equivalents of higher functional compounds for every 10 equivalents of bifunctional compounds, according to patent 1494452, characterized in that the reaction products in the presence of esters of titanium and / or zinc acids in such proportions that to 100 g of Reaction products 0.05 to 0.5 g, preferably 0.1 to 0.2 g of zirconium or titanium, have been prepared are.