Photobase Generating Reactions and Their Amplification

Abstract

Photo curing is used in fields related to electronics where heat treatment is not possible. Anionic UV curing using a photobase generating reaction has attracted attention because it does not corrode metals, but only a few articles have mentioned anionic UV curing materials have been reported. This is probably due to relatively low quantum yields for photobase generation and weaker basicity of photogenerated bases, leading to low photosensitivity of anionic UV curing materials. We report here novel photobase generators to release organic strong bases with high quantum yields and a novel concept of base proliferation to improve the photosensitivity of the anionic UV curing. The concept involves the basecatalyzed decomposition of an organic compound termed a base amplifier which produces a newborn base molecule, leading to its autocatalytic decomposition. The addition of base amplifiers to the anionic UV curing materials resulted in the marked improvement of photosensitivity because the number of photogenerated base molecules increases markedly as a result of the base proliferation reaction of the doped base amplifier.