Radiation Curing PDF Download

RADIATION CHEMISTRY AND ITS RELATIONSHIP TO the coating and paint technology industry involves the application of a low viscosity mixture principally comprised of reactive monomers and oligomers but containing, as well, conventional coating additives such as fillers, colorants in the form of dyes or pigments, surfactants, and so on to a substrate and exposing them to a radiation sourceparticularly ultraviolet (UV) or electron beam (EB) radiationfor very short periods of time. When required, as in UV radiation curing, a small amount of photoinitiator is included in the formulation. When exposed to the radiation source, the mixture of materials is almost instantaneously converted into an effectively cross-linked, high quality coating or other product [1]. Radiation technology, as applied to coatings, had its infancy in the late 1960s and early 1970s when governmental regulation began requiring that solvent emissions from paint and coatings be decreased and regulated. At that time, most coatings were formulated with high molecular weight polymers and large amounts (often 80 % or more) of inexpensive solvents and cosolvents that for the most part were emitted to the atmosphere. Regulation increasingly forced companies to decrease these emitted solvents, and it was in this environment that new technologies such as high solids, powder, and radiation-cured coatings were born. Changes were slow to come into being in the stodgy (at that time) paint and coatings business, but today each of these methods of formulation and curing has become an important part of the coating and paint business. RADTECH International is an association for ultraviolet and electron beam technology as related to radiation-cured products for the adhesive, coating, ink, paint, and related industries. This group publishes a report (RadTech Report) five times a year, conducts UV/EB technology expositions and conferences and publishes the conference proceedings, has various publication and information available, and maintains a link between the various facets of the UV/EB industry (see www.radtech.org).