| 摘要 |
PURPOSE:To improve a printed board basic sheet in electrical properties by a method wherein a polytetrafluoroethylene sheet made of unextended polytetrafluoroethylene fibers in a wet method is heated and sintered. CONSTITUTION:A printed board basic sheet formed by heating and sintering a sheet formed of unextended polytetrafluoroethylene fibers in a wet method is impregnated with phenolic resin or epoxy resin to be improved in laminating property to a metal foil, and a metal foil is laminated on the basic sheet to serve as a printed board. Therefore, inorganic fibers contained in PTFE fiber can be controlled in compounding ratio corresponding to required characteristics. By this setup, a printed board basic sheet improved in rigidity and flame- retardant properties can be obtained, where the electrical properties of PTFE fiber such that dielectric constant is stable to a wide range of frequency, a dielectric tangent is low, and characteristics are stable in a wide temperature range, can be utilized to the utmost. |
