Rendering foam surfaces plane to make high frequency circuit board involves coating them with flowing polymer mass to form layer smoothing-out irregularities, followed by hardening

摘要

Onto a foam substrate a flowing polymer mass is coated, to form a layer which smoothes out surface irregularities. The layer is then hardened. Onto a foam substrate a flowing polymer mass is coated, to form a layer which smoothes out surface irregularities. The layer is then hardened. Coating is centrifugal or is by spraying or immersion. Before hardening, further smoothing takes place, especially by thermal reduction of the layer viscosity for an interval. Hardening is induced by irradiation of the layer using UV light, or by temperature treatment. A flowing mass with a monomer and/or an oligomer is employed. The mass is blended with a solvent. It includes a starter for thermally- or photo-initiated crosslinking, or a hardening agent. An Independent claim is included for a foam board formed as described.