Radiation curing of inks and coatings :

Abstract

The science and technology of curing organic materials with radiation is reviewed.Electron beam, ultraviolet, infrared, microwave, and high' frequency radiation sources and the resin systems suitable for use with these sources are considered. I PURPOSE, SCOPE, AND SUMMARY OF THE REPORTThe purpose of this report is to survey the open literature on the radiation curing methods using inks primarily, but also other coatings, as a background for further research. Newer nonradiation methods and applications of radiation to fields other than coatings will also be considered briefly.The science and technology of curing organic materials with radiation is the subject of the first part of the report, Chapters II through VI.The opening section is primarily introductory in nature and encompasses a definition of the curing process, the motivations for exploiting solventless curing with radiation, the basic principles of the interaction of various forms of radiation with matter, and a kinetic scheme for polymerization and oxidation, chain reactions which can be initiated by molecular species excited by the aforementioned interactions.The following two chapters, III and IV, consider the most common radiation sources used to induce curing reactions: electron beams (EB)and ultraviolet (UV) light.The transfer of energy from electrons to molecules to form excited species and an indication of possible reactions that these excited molecules may undergo is outlined for materials subjected to EB bombardment. Since the energy imparted by UV radiation is much less than for EB, special excitable molecules referred to as photoinitiators or photosensitizers must be added to insure that exposure to UV light yields the desired chemically reactive species. The six major groups of these compounds are detailed, with examples of each type provided. The equipment necessary to affect a radiation cure is discussed and some practical problems unique to each of these radiation methods are indicated for both EB and UV curing systems.

Use of a gas chromatographic reactor to study lipid photooxidation

“…IGC is based on the interaction between a stationary phase ("unknown substrate") and a reactant ("known molecular probe") in the mobile phase (carrier gas, or solvent in HPLC). For a more detailed description of IGC theory, the reader is referred elsewhere (14).…”