Photo base generator

Photo base generator (PBG) generates anion (base) upon irradiation of light in the UV range. The technology of anionic UV curing using the base generated from PBG is expected to apply to various applications such as coating, ink, dental material, photoresist, etc. In addition to the originally developed PBGs, we have many variations of PBG co-developed with Arimitsu, an associate professor at Tokyo University of Science, in our lineup.

Characteristics of anionic UV curing

・Unlike the photoradical initiators, anion of active species is not deactivated by oxygen.
・Unlike the photoacid generators, corrosion of metal substrate and degradation of cured resin due to generated strong acid do not occur.


PBG is used for the crosslinking reaction of epoxy and isocyanate, the imidizing catalyst of polyamic acid, the sol-gel reaction of organosilane, the neutralizer of acid in resist polymer and so on.

Classification of PBGs

PBG materials are largely classified into “Ionic type” and “Non-ionic type”. Non-ionic type PBG materials generate primary and secondary amines and imidazoles, and are characterized by excellent stability and heat resistivity. On the other hand, Ionic type PBG materials generate strong organic bases such as tertiary amines, amidines and guanidines, and are characterized by high reactivity with crosslinking agents and monomers.

Effect of sensitizers

Photo-decomposition rate of WPBG-345 used with different photo sensitizers