Typical application of waterborne insulating varnish
● Alkyd type waterborne insulating varnish. It is the most used type of insulating varnish. Because the heat resistance of alkyd is not high, the anti-breakdown voltage is not strong, but alkyd is cheap and easy to obtain, so it is mainly used for the insulation treatment of small and medium-sized low-voltage motor electrical appliances.
● Waterborne polyester insulating varnish. The method for synthesizing this type of lacquer-based polyester is basically similar to that of water-based alkyd resin, but due to the introduction of more heat-resistant materials, the varnish is also superior in electrical insulation to water-based alkyd resins. Use of waterborne insulating paint of Class F and above.
● Waterborne epoxy insulating varnish. The epoxy resin paint has excellent mechanical strength and electrical properties, chemical resistance, good moisture resistance, small shrinkage, good adhesion and compatibility with other materials, but high price. This kind of insulating varnish not only has good performance, but also is safe and environmentally friendly, and the overall cost is low. The comprehensive performance can meet the requirements of F-class insulating varnish, and it is more suitable for the insulation performance requirements of small and medium-sized motors.
● Water-based polyimide insulating varnish. A high performance polymer with excellent thermal stability, outstanding mechanical properties and good electrical properties. It has been applied in the electromagnetic wire production line and entered the motor manufacturing practice verification stage.
Waterborne insulating varnish process considerations
Unbaked water-soluble insulating varnish may cause leakage or even burning, so it must be completely dried to achieve insulation.
●The viscosity of the paint must meet the requirements. Motors with different sizes and different models have different viscosity requirements for the paint. It is necessary to verify the specific process parameters.
● The air outlet of the kiln should be smooth to ensure that the water vapor can be discharged in time to make the paint film fully dry and solidified.
● The drying temperature should be above 120 °C. The larger the motor body size, the more complicated the structure, and the longer the drying time is.
●When the drying time is too long or the temperature is too high, the insulating sleeve may turn yellow or even black. A suitable insulating hose should be selected to prevent this problem.
● Check the withstand voltage and insulation resistance after exiting the kiln to check if it is dry.
● Water-soluble insulating varnish can not be mixed with other types of insulating varnish, otherwise it may become milky white or even deposit.
