Abstract: A multilayer printed circuit board can be used in high-frequency applications, is not easily affected by environmental changes, and has stable dielectric characteristics. A multilayer printed circuit board suitable for use in the high-frequency range includes at least two printed wiring sheets laminated with an interlayer bonding member therebetween. At least one of the at least two printed wiring sheets includes an insulating film, an adhesive layer containing a thermoplastic polyimide disposed on at least one surface of the insulating film, and a metal wiring layer disposed on the adhesive layer. The interlayer bonding member contains a thermoplastic polyimide.

Abstract: The present invention provides a reformed polyimide fluorocarbon resin laminated film having superior adhesive property with metals.The reformed polyimide fluorocarbon resin laminated film according to the present invention is constructed by that a surface of fluorocarbon resin of polyimide fluorocarbon resin laminated film having fluorocarbon resin being laminated on a single surface or both surfaces of a polyimide film is coated with a coupling agent, or executed with corona treatment.

Abstract: A fluoro-carbon resinous laminate has a crack-resistant surface on a fluoro-carbon resinous layer thereof produced by coating a single surface or both surfaces of a plastic film with a single layer of a fluoro-carbon resinous dispersion, and a method of producing the laminate. To produce the fluoro-carbon resinous laminate, which is a minimum of 10 .mu.m in thickness, a single surface or both surfaces of a plastic film are coating with a single layer of concentration-adjusted fluoro-carbon resinous dispersion and then dried, followed by curing the resinous dispersion in a thermal treating furnace with heated atmospheric air or by adding organic solvent to the resinous dispersion, the enabling production of a fluoro-carbon resinous laminate having a surface appearance in which cracks cannot visually be identified.

Abstract: The object of the invention is to embody further thinning of a double layer flexible printed circuit board (FPC) and provide a flexible copper-coated laminate capable of producing such a novel flexible printed circuit board distinguished in bending characteristic and heat-resistant property and provide a printed circuit board using the novel flexible copper-coated laminate. To achieve the above object, novel flexible copper-coated laminates 10 and 12 according to the present invention are respectively composed by directly forming a copper layer 16 having a thickness of 10 .mu.m or less than 10 .mu.m on a single surface or both surfaces of polyimide film 14 which is composed of polyimide polymer containing modulus of initial tensile elasticity of 400 kg/mm.sup.2 or more than 400 kg/mm.sup.2, and which has a thickness of 10 .mu.m or less than 10 .mu.m.