エポキシ樹脂用潜在性硬化剤としての 光カチオン重合開始剤の構造と特性Ⅱ

抄録

Following to a previous work, this article reviews the photo cationic polymerization initiators（ or the photo acid generators） including monoarylsulfonium, diaryliodonium, and ferrocenium salts available in the market as latent curing agents for epoxy resin. Monoarylsulfonium salt can polymerize epoxy resin cationically both by heat and by light although the photo-activation ability is generally poor compared to triarylsulfonium salt. Diaryliodonium salt is one of the major photo initiators comparable to triarylsulfonium salt, and also has the heat curing ability of epoxy resin. Various substituents, such as alkyl or alkoxy groups with different chain lengths, have been incorporated into the benzene ring of diaryliodonium salt in order to avoid the benzene emission, to improve the solubility with epoxy resin, and to reduce the toxicity originated from Iodonium. As a result, more than a dozen of improved diaryliodonium salt products are on the market. Ferrocenium salt（ or Fe-arena complex） can polymerize epoxy resin under the visible light although the applied market is still small. Taking CAS registration number as identification of the commercially available product, the article mainly focuses on reviewing the chemical structures and properties of above-mentioned photo cationic initiators together with the photo-activation mechanism of initiator and the cationic polymerization mechanism of epoxy resin.