PURPOSE: To satisfy various performance requirements of a flexible printed wiring board simultaneously by a method wherein an electrical insulating layer is made of polyurea resin which is obtained by the reaction between amine system compound of a specific composition and polyisocyanate compound and the like.
CONSTITUTION: Amine compound with a composition shown by the formula, aromatic polyamine and polyisocyanate compound are made to react with each other and cured. In the formula, R denotes n-valent polyalkylene, polyalkylene ester or polyalkylene polyester with an average molecular weight not less than 200. (A) denotes oxygen atom or imino group. (n) denotes positive integer 1, 2 or 3 and (m) denotes positive integer 2, 3 or 4. Electrical insulating layer made of polyurea resin obtained like this is used as the material of a substrate or a cover-lay film. As a result, a flexible printed board which has excellent solderability, foldability and adhesiveness and conforms to various high performance requirements of a flexible printed board and can be manufactured with a low cost can be obtained.
Koyaizu, Zenjiro
Hattori, Masaaki
