Trying to find some relationship between the observabil […]
Trying to find some relationship between the observability of the enameled wire and the chemical composition of the enamel used is a difficult but significant task. We do not yet have a complete understanding of this issue, but the results we have reached are worth mentioning.
The general principle of paint glaze structure Paint can be divided into two groups: physical drying and chemical drying. The physical drying paint consists of a volatile solvent with a macromolecular substance into which nitrocellulose is dissolved. When this varnish is applied to an object, the solvent evaporates and the residue forms a layer on the object. The process takes place without any chemical changes, ie the molecules do not react with each other. The enamel layer thus formed can be redissolved in the original solvent and also has a tendency to soften when heated. So these paints are sometimes too
Known as thermoplastic paint.
If the lacquer molecules do react with each other, an enamel layer with completely different properties is obtained, forming a three-dimensional network, as with the use of a chemically dried paint. The layer thus formed does not soften on heating and is resistant to common solvents (although it may swell to some extent in some cases).
Obviously, only the second type of paint (also referred to as thermosetting paint) is considered for use as a enameled wire insulation material. Thermoplastic lacquers are sometimes used as additional layers on wires that have been insulated with thermosetting varnishes. When a coil wound with this enameled wire is heated, the outer layer softens, causing work to adhere to the copper everywhere, and the glaze layer is easily stretched by the copper without breaking.
We will refer to the oldest lacquer, paint, and the third general "structural principle" of lacquer enamel. Paint is based on the principle of returning to the last century, for example, carriage paint. The main ingredients of this paint are natural resins (rosin, coconut oil) and drying oils (linseed oil, tung oil). Modern line enamel oil based still use natural drying oil. However, natural resins have been replaced by synthetic resins, which have the advantage of a more constant composition and a broader range of properties.