PRODUCTION OF LAMINATED SHEET AND COMPOSITE FILM FOR LAMINATED SHEET

摘要

PURPOSE:To produce a laminated sheet of a low dielectric constant enhanced in the thickness accuracy, reduced in the coefficient of linear expansion in a thickness direction, excellent in solder heat resistance, reduced in the mixing with foreign matter and enhanced in bonding strength. CONSTITUTION:A base material 1 is impregnated with a dispersion of a PTFE resin 2 and the impregnated base material is dried at a temp. lower than the m.p. of the PTFE resin 2 and impregnation and drying are repeated to form a non-sintered prepreg 3 holding a necessary amt. of the resin while a composite film 6 for a laminated sheet having a two-layered structure consisting one layer composed of a PTFE resin and other layer formed from fluororesin 5 whose m.p. is lower than that of the PTFE resin 4 is formed. A metal foil 23 is arranged on at least the single outer layer of the non-sintered prepreg 3 through the composite film 6 and the whole is pressed at a temp. higher than the melting points of the PTFE resins 2,4.