A kind of method of producing polyesterimide enameled wire varnish

Abstract

The invention relates to a method for producing polyester-imine wire coating enamel. The method is characterized by comprising the following steps: firstly, performing ester exchange reaction on dimethyl terephthalate, ethylene glycol and THEIC under the catalysis of tetrabutyl titanate; reserving methanol in a reflux tank of methanol in advance; pumping methanol to the top of a rectification column by virtue of a reflux pump for reflux to wash sublimated dimethyl terephthalate; after the ester exchange reaction ends, adding trimellitic anhydride and 4,4'-diaminodiphenylmethane by precisely controlling the feeding temperature of imidization reaction to prepare polyester imide resin; secondly, mixing and blending the polyester imide resin, bisphenol A modified phenolic resin, poly butyl titanate, high methyl-etherified melamine resin, sodium perfluorononoxy benzene sulfonate and an S-100 solvent to obtain paint. The prepared polyester-imine wire coating enamel has good lubricating property and leveling property, and is convenient for downstream users to coat lines under high DV values; an enamelled wire obtained by coating the lines by using the paint has good thermal property and mechanical property.

Description

technical field [0001] The invention relates to a production method of polyesterimide wire enamel, which belongs to the field of wire enamel production. Background technique [0002] The main chain structure of the polyesterimide molecule contains both an ester group and a heat-resistant imide ring, so it has both the flexibility of polyester and the heat resistance of polyimide. The performance of polyesterimide wire enamel is between polyimide wire enamel and polyester wire enamel. Its heat resistance is better than that of polyester, its raw material cost is lower than that of polyimide, and its processability has also been significantly improved. Therefore, in foreign countries, polyester paint has been basically replaced by polyesterimide paint. Polyesterimide wire enamel has been widely used in electrical equipment such as transformers, refrigerators, freezers and industrial refrigeration motors. [0003] Chinese publication CN1670054A discloses the use of terephthal...

AI Technical Summary

Problems solved by technology

The price of Pt is very high, and it is doubtful whether elemental Pt can be directly used as a catalyst

[0004] In fact, terephthalic acid will not melt until it is heated above 425°C, and it will also sublime above 300°C. Although it will undergo esterification reaction with alcohol in the temperature range of 200-220°C, that is in Heterogeneous reaction under liquid-solid conditions, the reaction is slow and uneven