α-Ketoesters as Nonaromatic Photoinitiators for Radical Polymerization of (Meth)acrylates

Photopolymerization of (meth)acrylate-based formulations has become a widespread method for industry due to the high energy efficiency and low curing times of this technology. Various products from simple coatings to more complex applications such as additive manufacturing technologies are based on this versatile method. Common industrial radical photoinitiators are generally based on aromatic ketones with the benzoyl chromophore as the key constituent. In medical or food packaging applications, residual photoinitiator or photoproducts migrating into the product have to be avoided, particularly for toxicological reasons. In this paper we present a new generation of nonaromatic initiator systems. Besides their good reactivity in (meth)acrylic formulations, they show good bleaching properties and high biocompatibility.