High performance radical and cationic initiators with low emission properties

High UV curing performance alone is no longer sufficient for sensitive applications. Low emission and low migration have become critical requirements for photoinitiators. A new, tetrafunctional -hydroxyketone radical photoinitiator showing a unique combination of low migration and high cure speed in spite of its high molecular weight (> 800 Da) is presented.

A new triarylsulfonium photoinitiator with low volatile primary photocleavage products has been developed for cationic curing. Experimental results in clear varnishes, printing inks, and adhesives, demonstrate that it can compete with the state of the art. Set-off migration experiments confirm the very low emission profile and technical suitability of both initiators for sensitive application such as food packaging.