Knowledge base

UV inkjet made tremendous progress in productivity and print quality in recent years. Market penetration in graphic arts picks up speed making traditional UV offset and UV flexo face increased competition from UV inkjet, particularly in label and packaging printing. Difficulties realising food contact compliance are a major concern limiting the gro

New EB CI-flexo ink technology has been developed to permit wet trapping without interstation hot air drying. This ink technology uses electron beam initiated free radical polymerization to achieve cure, and wet trapping is obtained by organo-jellification mechanism using Hansen Solubility Parameters (HSP). This patented new printing process was de

The present work addresses the formation of 3D structures via UV assisted foaming of commercially available acrylic offset inks. The microcellular foaming relies on the excitation of selected photoacid generators with UV light to release Brønsted acids. Once formed, the acids react with calcium carbonate particles under the release of carbon dioxid

Curing water-based formulations with photoinitiators is a state of the art technique. However, the commercially available Norrish type II water-compatible photoinitiators disappeared from the market since the bimolecularity and the resulting solvent cage in a water-based solution lead to a loss in reactivity. Since a few decades there is only one c

In the broad field of photopolymers three dimensional networks are formed by free-radical polymerization. These networks have to fulfill a variety of requirements including high reactivity of the monomers and good mechanical properties. During polymerization an inhomogeneous network forms, that decreases the mechanical properties of the polymer and

Addition fragmentation chain transfer agents (CTAs) are an upcoming important group of compounds used for controlling radical polymerization.1 Generally, AFCT reagents are known from thermal radical polymerization in solution, photoinitiated, controlled bulk polymerization is rarely found in literature. Transforming an uncontrolled radical chain re

Photopolymerization traditionally involves the use of multifunctional monomers and oligomers thus leading the formation of tridimensional networks. Use of nonfunctional monomers opens the way to the formation of linear photopolymer chains presenting recyclable possibilities. Thermoplastics are generally synthetized by thermal way at high temperatur

Optimization of holography recording in photopolymers was studied from the point of view of the photogeneration of radicals. On the basis of a dye/borate salt photoinitiating system, the effect of the primary events and their relative efficiency was investigated with respect to the final overall properties, such as the diffraction efficiency. Quenc