Recent developments in radiation curing in the USA

Radiation curing activities in the USA focus strongly on the use of both UV and EB for the polymerization of silicone release coatings on paper and film. The high speeds of cure (200 m/minute) achievable at ''room temperature'' continue to make this the process of choice for the siliconization of both film and paper. Some of the process difficulties peculiar to this chemistry will be discussed. The success of the multi-color lithographic printing of web using single station electron curing has resulted in a major market for electron processors. The aesthetic and physical properties of the overprint varnishes used in this application are important and will be discussed. The relatively high costs of both the inks and varnishes will probably limit this application to folding carton use for foodstuffs and high quality products, with UV continuing to dominate in lower speed, less demanding applications. The application of electron initiated graft modification of polymer materials, particularly for biological/medical device application, is showing a good rate of development as is the use of selective treatment of materials for functional modification of packaging films, particularly for gas permeability control. Some examples of these applications will be reviewed. Continued work with ''deep'' curing or vulcanization of composite structures, particularly in the elastomers field, will be discussed with a brief review of the continuing growth of electron processing in this industry, particularly for tyres and roofing products. (author)