Patent ID: 8501279
Filing Date: 2013-08-06
Classification: H05K,Y10T

Abstract:
1. A process for production of a flexible laminated sheet having one or more laminated bodies each provided with a metal foil formed on one side of a resin film, the process comprising: a coating step in which a varnish containing a polyamic acid and a solvent is coated onto the metal foil to form a coated film; a holding step in which the coated film formed on the metal foil is held; a drying step in which at least a portion of the solvent in the varnish is removed to form a layer composed of a resin composition, the solvent in the varnish being removed to a proportion of 1-60 wt % of the total, wherein the drying step is performed subsequent to the holding step; and a resin film-forming step in which the layer composed of the resin composition is heated to form the resin film, the resin film containing a polyimide resin, wherein the process includes adjusting the conditions for each step after the coating step and up to the resin film-forming step so that the content of metal elements in the resin film at a depth of 0.05 μm from a main surface side of the resin film adjacent to the metal foil is no greater than 5 wt % and a relative permittivity of the resin film at 5 GHz is no greater than 3.3.