A kind of synthesis method of high heat-resistant grade polyester type polyurethane wire enamel

Abstract

The invention discloses a synthetic method of a polyester type polyurethane enamelled wire varnish with a high heat-resistant grade, the enamelled wire varnish prepared by adopting the method has high heat-resistant performance and the heat-resistant grade reaches 200 or above. The synthetic method disclosed by the invention is characterized by comprising the synthetic processes of imine and ethanol amine modified polyester resin as follows: adding diethylene glycol, diethanol amine, trimethylol propane, tris-(2-hydroxyethyl) cyanuric acid and a catalyst into a reactor; heating the mixture to 100 to 120 DEG C; further adding dimethyl terephthalate, partial dianhydride and modified imine dicarboxylic acid; heating to 140 to 150 DEG C; reacting for more than 4 h; heating to 220 to 230 DEG C; reacting for more than 12 h; conducting vacuum operation when the temperature of a distillation head is below 65 DEG C until the viscosity is between 1300 to 1800 mPa.s (25 DEG C); adding cresol and xylene and stirring for dissolving and clarifying to obtain the imine and ethanol amine modified polyester resin until the solid content reaches 44%.

Description

technical field

[0001] The invention relates to a method for synthesizing polyurethane varnish, in particular to a method for synthesizing high-grade heat-resistant polyester-type polyurethane enameled wire varnish, which belongs to the field of electrical insulation. Background technique

[0002] Enameled wire enamel is one of the main varieties of insulating varnish. It is a special coating for coating motors, wires and electrical appliances. Apply a layer of insulating varnish that can block the current so that the current can pass through it according to the normal path. The paint film of wire enamel generally has good insulation, good heat resistance, good mechanical properties and good chemical resistance. Wire enamel is generally mainly composed of film-forming substances, solvents, and auxiliary materials. Among them, polyurethane enameled wire varnish has the following characteristics due to its unique structure: ①Good direct solderability. When welding polyuretha...

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