Basf Aktiengesellschaft

Hans Jung

Jenoe Kovacs

Matthias Marx

Herbert Spoor

Helmut Lehmann

Wilhelm Dussel

Wilfried Roschke

A process for the electrical insulation of wire by enamelling, using aqueous dispersions which are applied thereto by means of applicator rollers. The thickness of the dispersion coating on the wire can be varied by merely suitably selecting the circumferential speed of the applicator rollers.

Electrical insulation of metallic conductors

A polyamide-imide precondensate which is solid at room temperature, but is fusible and soluble in polar solvents. It is manufactured by first condensing 1 mole of diamine with 2 moles of tricarboxylic acid anhydride in a diol as the solvent, to give a diimide-dicarboxylic acid, then esterifying the diimide-dicarboxylic acid with the diol and finally effecting the polycondensation by adding 1 mole of diamine per mole of diester. The precondensate may be used, as a melt, as a solution in organic solvents or as an aqueous dispersion, for coating electrical conductors.

Polyamide-imide precondensates

A process for the electrical insulation of metallic conductors by coating wires with aqueous dispersions of coating materials, comprising the following steps which are carried out in a single cycle: introducing the starting dispersion into a storage zone A; continuously withdrawing part of the dispersion from the storage zone and feeding said part to a dispersing zone, where it is homogenized and comminuted; if necessary, cooling the dispersion to below 40.degree. C in a cooling zone; feeding the dispersion to a fractionating zone D, where it is separated into a coarse fraction and a fine fraction; and finally, passing the fine fraction through coating zones E, through which wires are drawn so as to receive a coating.

Process for the manufacture of polyester imides. Melamine, an at least tribasic carboxylic acid, a polyhydric alcohol and, optionally, an aromatic dicarboxylic acid are condensed at elevated temperature. The polyester imides are suitable, in the form of solutions, aqueous dispersions or melts, for use as baking enamels for metallic conductors.

Process for the manufacture of polyester imides using melamine as the

Aqueous polyester imide dispersions are prepared by allowing molten polyester imide to solidify and then comminuting it in the dry state to a particle size of 100 .mu.m or less, whereupon the particles are milled in water to a particle size of less than 5 .mu.um. The dispersions may be used for the manufacture of heat-resistant bonds and impregnations and for electrical insulation of metallic conductors. m.

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Ludwigshafen, Germany

Hans Jung