Radiation curing of commercial paint samples

Radiation curable coatings which include inks, varnishes, adhesives and paints, are reactive mixtures. They contain oligomers, monomers, pigments, initiators and additives. On being irradiated, these substances polymerize to form a three dimensional thermoset polymer film. The film properties are dependent on the paint formulation and the radiation used for curing. The aim of these experiments was to explore the radiation curability of commercially available paints and to apply the results to E-Beam curing of such paints using the 750 keV D.C. accelerator. The energy requirement will be ∼0.4 MeV. For our preliminary experiments an oil paint generally used for indoor and outdoor applications and a nitrocellulose based automotive paint were chosen. The E Beam has been substituted by gamma radiation from a 60Co source in these studies. Though the primary interaction with matter is different, the major interaction with matter for both is Compton scattering. Another major distinction to take into account in applying these results to E beam curing is the dose rate. The gamma radiator used delivers dose rates up to a maximum of ∼5 kGy/h. The electron accelerator planned to use can deliver doses orders of magnitude higher. This will reduce the irradiation time for a dose of 100 kGy from ∼20 hours to ∼0.5 seconds for E beam