Radiation curing of coatings

Koleske, J. V., Radiation Curing of Coatings, ASTM International, West Conshohocken, PA, p. 30 (2002). 

Narey B., Conference Proceedings, Innovation in Plastics Plastics Technologies for A Global Competitive Edge, Rochester, NY, September 18-19, 1990, Paper J.012. Koleske, J.V., Radiation Curing of Coatings, ASTM International, West Consho-hoken, PA, p. 216 (2002). 

Raney, M. W. "Electrodeposition and Radiation Curing of Coatings" Noyes Data Corp. Park Ridge, N.J., 1970. 

Both electron beams and ultraviolet light initiate free-radical polymerizations with very low activation energy. This allows high polymerization rates at room temperature because the rates are not temperature dependent. Once initiated, free-radical polymerizations follow typical paths. It is, however, peculiar to radiation curing of coating materials that the gel states form at very early stages of the reactions. This is due to extensive use of polyfunctional monomers and prepolymers. In fact, it was demonstrated that the gel points occur at around 5% conversion of the prepolymers in typical commercial formulation, yet conversions to about 63% of the prepolymers to polymers are required to obtain dry films. ... 

The Curing of Coatings with UItra-Uiolet Radiation, D8667 G.D., Tioxide of Canada, Sorel, P.Q., Canada. 

Radiation curing of epoxies with cationic initiators is well known [20—28]. UV-visible light has been the predominant radiation source the process has been limited to thin coatings due to the low penetration of the visible-UV light [22,23], Thermal and mechanical properties of these materials are low and the curing is incomplete. Several studies have shown that commercially available epoxies with various cationic initiators can be polymerized with EB curing [20,29-34]. 

Studies of several investigators have shown that polyfunctional thiol compounds are useful as cross-linking agents for the radiation curing of unsaturated elastomers and polymers used in graphic arts, electronics, and coating industries. Already small amounts of these compounds enhance the... 

The yields of radiation-induced polymerizations can be very high. No additives are required, which makes it possible to synthesize very pure polymers. The initiation step is temperature independent giving rise to an easily controlled process at any desired temperature. These features account for the commercial interest in radiation polymerization. The very high speeds attainable within the layers of monomers subjected to powerful electron beams explain the wide use of this technique in radiation curing of adhesives, inks and coatings. The corresponding formulations are "solvent-free" and involve pre-polymers and monomers as reactive diluents. 

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