Resin induced impurities

Typically, the reaction mechanism proceeds as follows [6], By photoreaction, two chlorine radicals are formed. These radicals react with the alkyl aromatic to yield a corresponding benzyl radical. This radical, in turn, breaks off the chlorine moiety to yield a new chlorine radical and is substituted by the other chlorine, giving the final product. Too many chlorine radicals lead to recombination or undesired secondary reactions. Furthermore, metallic impurities in micro reactors can act as Lewis catalysts, promoting ring substitution. Friedel-Crafts catalyst such as FeClj may induce the formation of resin-Uke products. 

In 1974, a patch test with an epoxy resin was reported to induce generalised urticaria and an asthmatic reaction (Woyton et al. 1974). In 1983, Suhonen reported on two patients who, in a patch test, showed immediate urticarial reactions, probably due to an impure DGEBA epoxy resin used in a ski-pole factory. Kanerva et al. (1991c) described two patients with both immediate and delayed allergy to DGEBA epoxy resin. 

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