Current status of medium and low energy electron beam accelerators and their applications

Electron Beam (EB) use has been increasing in popularity as a crosslinking process over the past several years. Examples of EB use are heat resistance improvement of electric wires, high quality foamed polyethylene (PE) and polypropylene (PP), Automotive Tire manufacturing and heat-shrinkable film. EB process is used in the Tire manufacturing as a pre-vulcanization of rubber sheet before forming process. EB improves the green strength of rubber sheet and it makes it possible to maintain the shape or size of the original until completion of final vulcanization. It is said that this effect is useful for reducing the consumption of rubber material. The application of Low energy electron beam accelerators (low energy EB) is mainly used to cure resins or coatings and it has been gradually spreading to the industrial field such as pressure sensitive adhesives, release paper, transfer film, etc. Low energy EB curing is often compared with Ultra-Violet (UV) curing, but commercialized application indicate there is an advantage for the EB process. A typical advantage is that no initiators are required to start curing, which UV requires. EB curing may be used to supplement disadvantages of UV such as weatherability, color limitation, etc. In addition to these, EB process is spreading by using its original advantages, of high cross-link density, small heat influence on the substrate and no solvent requirement. EB can also be used to remove So2 and Nox from coal flue gas and for sterilizing medical devices. EB has a great advantage which includes simultaneous removal of So2 and Nox and the by-product can be used as a fertilizer. The sterilization by Electron Beam is expected to be an alternative to gas sterilization which has some safety issues likely to be discussed in the future projects. (J.P.N.)