Dialkyphenacylsulfonium Salts: A new Class of Cationic Photoinitiators

In recent years, cationic UV curing has become a well-established method in the coatings, inks
and adhesives industries. Today, UV curing continues strong growth impelled by the generally
excellent chemical resistance and mechanical properties of polymers produced by the UV cure of
such monomers as epoxides and vinyl ethers. Photoinitiated cationic polymerizations have the
added advantages of oxygen insensitivity together with the use of monomers with low toxicities.
At the present time, there are three major classes of cationic photoinitiators that are employed in
commercial applications: diaryliodonium salts (I), triarylsulfonium salts (II) and ferrocenium salts