Patent ID: 6103157
Filing Date: 2000-08-15
Classification: C08K,C08L,H01B,H01F

Abstract:
A process for impregnating an electrical coil made up of two or more layers consisting of more than one turn of an electrically conducting material in wire form, which process comprises impregnating the coil with a thermally curable epoxy resin composition that is solid at room temperature and comprises(a) an epoxy resin which is solid at room temperature, selected from(a1) polyglycidyl ethers based on novolaks;(a2) diglycidyl ethers based on bisphenols, and(a3) mixtures of more than one of components (a1) and (a2);(b) a crosslinking agent for component (a);(c) a suitable accelerator for the reaction of component (a) and component (b);(d) from 15 to 70 percent by weight, based on the overall weight of the composition, of filler selected from(d1) calcium carbonate,(d2) quartz flour,(d3) wollastonite whose particles have an average ratio of length to cross-section which is less than 5:1;(d4) mixtures of components (d1), (d2) and (d3) and(d5) mixtures of components (d1), (d2), (d3) and (d4) with other inorganic fillers,wherein the epoxy resin composition electrically insulates the individual turns of the material in wire form from one another.