A kind of water-based insulating varnish for electronic transformer and its preparation method and application

Abstract

Disclosed is a water-based insulating varnish for a transformer, a preparation method thereof, and an application thereof in dipping a transformer. Raw materials of the insulating varnish comprise polyol, acid anhydride, a neutralizing agent, a co-solvent, a water-based curing agent, water, diisocyanate and a chain extender. The polyol is composed of glycerol and neopentyl glycol. The acid anhydride is composed of phthalic anhydride and trimellitic anhydride. By means of mixing glycerol, neopentyl glycol, phthalic anhydride and trimellitic anhydride and causing a polycondensation reaction, a hydroxyl-terminated hyperbranched polyester is prepared. The hydroxyl-terminated hyperbranched polyester is reacted with diisocyanate, and then the neutralizing agent, the co-solvent, the chain extender and water are added and reacted. The water-based curing agent is then added and mixed to obtain the insulating varnish. The insulating varnish can prevent the transformer dipped with the water-based insulating varnish from being subjected to a secondary soldering at a high temperature of about 400°C, and can impart thereto soldering and conductive characteristics at an operating temperature of a plug-in circuit board, and can be further applied to a plug-in circuit board, streamlining process steps and saving energy.

Description

technical field [0001] The invention belongs to the field of insulating impregnating varnishes for electrical equipment, and in particular relates to a water-based insulating varnish for electronic transformers and a preparation method and application thereof. Background technique [0002] At present, electronic transformers on the market require secondary soldering after being impregnated with insulating varnish, but most of the water-based insulating varnishes on the market cannot meet the requirements of secondary soldering. To solve the problem that the above-mentioned water-based varnish cannot be soldered twice, the Chinese invention patent CN105348502B discloses a A water-based insulating varnish and its preparation method. However, although this patent can impart secondary soldering properties to the water-based varnish, it needs to perform secondary soldering on the electronic transformer dipped in the insulating varnish at a high temperature of about 460°C to endow ...

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Problems solved by technology

[0002] At present, electronic transformers on the market require secondary soldering after being impregnated with insulating varnish, but most of the water-based insulating varnishes on the market cannot meet the requirements of secondary soldering. To solve the problem that the above-mentioned water-based varnish cannot be soldered twice, the Chinese invention patent CN105348502B discloses a A water-based insulating varnish and its preparation method. However, although this patent can endow the water-based varnish with secondary soldering properties, it needs to perform secondary soldering on the electronic transformer impregnated with insulating varnish at a high temperature of about 460°C to endow it with conductivity. Then it can be applied in the subsequent process of inserting circuit boards (working temperature is about 260°C), the energy consumption is high, which is not conducive to saving energy, and it increases the production process and increases the production cost

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