Historical background
Mica, in its muscovite or phlogopite form, is a natural product with exceptional electrical, mechanical and thermal properties, and resistance to chemical agents, which have long made it a favorite of the electrical engineering industry.
It was first used in the form of cleavages produced by careful hand cleavage of mica rock blocks, combined with reinforcements of paper, cotton or, later, glass cloth and various resins or varnishes, to give it a certain continuity for use as ribbon.
The cleavages were also agglomerated with a resin in plate form to make up all the Micanites (in flexible form, for heating, for collectors, moldable).
The cleavages could also be molded to form mica parts (manifold cones, cylinders, tubes).
Unfortunately,...