DE1794233A1 - Insulating coating agents with high heat resistance - Google Patents

Description

"Insulating coatings with high heat resistance." New insulating Coating agents with high heat resistance consist of reaction products of terephthalic acid or their derivatives (I), e.g. B. dimethyl terephthalate (I), heterocyclic monocarboxylic acids or their derivatives, e.g. B.

Atophane, 2,6, -dihydroxy = isonicotinic acid, furancarboxylic acid, furancarboxylic acid methyl ester, Hemopyrrolecarboxylic acid, pyridinecarboxylic acid, phenylcarboxypyrazolone, phenylpyrrolidonecarboxylic acid, Uracilcarboxylic acid (II), and tri- or polyhydric alcohols (III).

The process for the preparation of the coating agent consists in that the components mentioned with or without the presence of solvents, e.g. B. xylene, Methanol, at elevated temperatures, e.g. B. over 100 ° C, together or in different Stages, e.g. B. first reaction of the trihydric or very hydric alcohol with the monocarboxylic acids or their derivatives, followed by further reaction with ferephthalic acid or their derivatives, are implemented and the reaction products before and / or after be subjected to thermal aftertreatment before being applied to a substrate.

When using dimethyl terephthalate and heterocyclic products together Monocarboxylic acids can initially be the methyl ester of the heterocyclic as an intermediate Form monocarboxylic acid to the same extent as methanol from I) iaethyl terephthalate in the Reaction with trivalent or polyhydric alcohols is split off and this methyl ester the heterocyclic monocarboxylic acid in turn reacts with elimination of methanol min the tri- or polyhydric alcohols. This procedure or the implementation in the first stage in the presence of methanol are important insofar as this the implementation of the often poorly soluble heterocyclic monocarboxylic acids is decisive can be influenced.

Furthermore, it has been shown in connection with the present bridge that that during the reaction or during the thermal aftertreatment of the reaction products Changes in the nitrogen of the heterocyclic monocarboxylic acids, e.g. B. Release of amines in the event of the possible decomposition of uracil carboxylic acid, and which Nitrogen fixation can be included in the new reaction products, what z. B. to VrIiegen of nitrogen double bonds aer heterocyclic monocarboxylic acids or their derivatives can be accepted.

New insulating covering material of high heat resistance are after the application to a base, e.g. B. Xtahlblech, copper wire, and then thermal post-treatment before.

The order on a base can be done by terra pipes known per se take place, e.g. B. as a solution in cresol or by electrostatic spraying of the pulverulent new conversion products. The new ones are for powder application Coating agent goose particularly suitable because the use of the heterocyclic Monocarboxylic acids are the most suitable melting point for the respective application the reaction products can be precisely adjusted in a narrow melting range.

Of course, other substances known per se, e.g. B. Others Resins, aminoplasts, pigments, solvents, hardeners, titanium butylate are also used will.

The following example only illustrates the procedure for the manufacture and the insulating coating agent of high heat resistance without claim to be complete.

Example: 5 moles of glycerine are heated to 1200C in the presence of xylene, 2.6 moles of orotic acid sprinkled in and finely distributed by stirring. The temperature will under light Vaouum and distilling off xylene / water up to a maximum 2200C, preferably 1800C, until the initially beet start is clear what with an SZ of 150-200 and distilling off about 80 T. water is the case. Now it is allowed to cool down to 1200C, 90 T. of a zinc octoate solution, 8% Zn, added and then set in the usual way with 4.4 mol of dimethyl terephthalate and more slowly and continuous elimination of methanol at a temperature of up to 2000C to the theoretical amount of methanol has practically passed over.

Now condensation continues at a maximum of 2400C under vacuum until a 33, 'ige Solution in cresol has a viscosity of 3000-3500 oP.

The resulting resin-like reaction product receives a Addition of 1% polymeric titanium butylate strbilised by means of ethyl glycol as hardener and 1 * iso-octanol as a leveling agent and is used after the electrostatic powder application (40-60'KV) on sheet steel of a thermal aftertreatment by Smin. Subject to 2200C or in the form of the cresolic solution used as wire enamel for copper wires, whereby the thermal post-treatment in the usual way when passing through the drying ovens, z. B. at a set temperature of 3600C.

It should be noted that darkening and partial decomposition of Orotic acid with elimination of amines in the; the first stage of implementation can occur, if the temperature is above 2200C, e.g. B. to 250 ° C is increased.

Claims (3)

P a t e n t a n s p r ü c h e: 1. Highly insulating coating agents Heat resistance, characterized in that they are reaction products of terephthalic acid or their derivatives (I), heterocyclic monocarboxylic acids or their derivatives (II), and- trihydric or polyhydric alcohols (III) contain. 2. Process for the production of the coating agent according to claim 1, characterized in that characterized in that terephthalic acid or its derivatives (I), heterocyclic monocarboxylic acids or their derivatives (II) at temperatures above 1000C with or without the presence of Solvents are reacted with trihydric or polyhydric alcohols and the reaction products before and / or after application to a substrate of a thermal aftertreatment be subjected. 3. The method according to claim 2, characterized in that as heterocyclic Conocarboxylic acid pyridine carboxylic acid or uracil carboxylic acid is used.