| abstract |
A means for treating the end faces of a core whichnis used for an electrical apparatuses and etc., to giveninsulation extremely superior in effect of improvement ofnthe insulation, corrosion resistance, adhesiveness, heatnresistance, and magnetic properties at a low temperaturenin a short time without cleaning for removing punchingnoil, annealing, or other pre-treatment; a core having anninsulation coating comprising a dry film of a purensilicone polymer, modified silicone polymer, and/or mixednsilicone polymer as a silicone compound on the core endnfaces and having an average film thickness of at leastn0.5 µm, a breakdown voltage of at least 30V, and a heatnresistance in the air of at least 400°C; and a method ofnproduction comprising forming a core, then dipping it innor spraying it by one or more types of a pure siliconenpolymer, modified silicone polymer, and/or mixed siliconenpolymer as an insulation coating. |