3. Enamelling varnish

It is characterized by the chemical nature of the prepolymer, the mass ratio of prepolymer to solvent (dry extract) and the viscosity of the mixture. Depending on the chemical nature of the enamel, the type of enamelling machine used and the diameter of the wires, enamelling varnish contains between 18 and 40% dry extract (useful part); the remainder is made up of the solvents burned in the enamelling furnace.

Nevertheless, the solvent formulation plays an important role in the quality of the yarn obtained. It generally consists of...