| 摘要 |
PROBLEM TO BE SOLVED: To obtain a multilayer printed wiring board undercoating agent which is turned tack-free by active energy rays and completing cured by heat by a method wherein said undercoating agent is composed of novolac type resin, having a bromination ratio of specific value or more and the molecular weight of specific value or more, and bisphenol type epoxy resin and the like. SOLUTION: Undercoating material is applied between the copper foil circuits of an interlayer circuit board and the internal circuit board is smooth-faced. The undercoating material is made of novolac type epoxy resin, having a bromination percentage of 20% or higher and the molecular weight of 500 to 4000, bisphenol type epoxy resin having the molecular weight of 2000 or smaller, photopolymerization and heat reactive monomer and photopolimerization initiator. As a result, the undercoating agent can be turned tack-free excellently by the irradiation with activated energy rays. The obtained multilayer printed wiring board is excellent in preciseness in board thickness, and excellent both in heat resisting property and nonflammability. |
