Impregnating Paint and Its Properties in Insulating Varnish
The impregnating varnish is divided into two main categories: solvent paint and solventless paint. It is mainly used for impregnating the coil of motor and electrical appliance to fill gaps and micropores. After curing, it can form continuous and smooth film on the surface of the impregnated material and make it bond into a hard whole.
The basic requirements for impregnating lacquer are the following:
1. the viscosity is low, the fluidity is good, the solid content is high, and it is easy to permeate and fill the impregnated material.
2. fast curing, good drying performance, strong bonding force, thermoelastic, after curing can withstand the centrifugal force when the motor rotates.
3. It has excellent electrical and chemical stability, moisture resistance, heat resistance and oil resistance.
4. Good compatibility between conductors and other materials.
The insulating impregnated paint must have the following performance standards:
1. appearance: transparent and uniform liquid, no mechanical impurities, lacquer film smooth and bright.
2. viscosity: must be allocated to the appropriate viscosity to ensure the best penetration and the amount of paint when the coil is impregnated. The amount of diluent can be determined according to the size of the coil and the gap between the coil and the winding.
3. drying time: in order to save energy and improve the efficiency, we should vigorously promote the use of fast drying and low curing temperature of insulating paint.
4. Solid content: the solid content is only for solvent lacquer. Now, the high solid and low viscosity lacquer is recommended internationally. The solid content of the insulating paint produced in our country is generally not less than 45%. For solventless impregnating lacquer, the general type solvent free lacquer is generally used as a solvent free paint, and the volatilization is not more than 15%.
5. thick layer curing ability: This is one of the main technical indexes for assessing the comprehensive performance of insulating paint. Require thick layer drying to solidify evenly, no bubbles, no cracking, soft as rubber.
6. elasticity: insulation paint must have good flexibility (that is, elasticity) and good adhesion, not too crisp. Generally speaking, the film is bent 180 degrees through the 3MM core axis, and the film should not be cracked, and the coating can not fall off.
7. dielectric properties: insulation paint must have high breakdown strength and volume resistivity.
8. the effect of lacquer on enameled wire: all coil windings must be enameled, so insulating impregnating varnish must be compatible with enameled wire and can not corrode the surface insulation layer of enameled wire. The effect of lacquer on enameled wire is generally expressed by pencil hardness. The industry standard stipulates that the hardness of the paint for the enameled wire is not soft to 1H.
9. corrosion resistance: insulation impregnating paint must have good solvent resistance steam and moisture resistance, salt fog resistance and cold and thermal shock resistance.