UV and EB

Energy sources are typically Electron accelerators are used (150-500kV)  

It is understood that UV requires more energy than EB  

The process requires a photoinitiator EB itself has sufficient energy to initiate polymerisation  

N2 not always required Requires N2 for free radical compositions 

Penetration decreases exponentially through Penetration more uniform dependent 

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This technique is used for the production of radiation-cured coatings, adhesives, and inks. The process is not accompanied by the release of heat, which is particularly important in the case of heat-sensitive materials, e.g., wood, cardboard, paper, plastics, etc. Various radiation sources are used for this technique, among which UV and EB are most useful. 

Osaka Organic Chemical will embark on volume production of a low-toxicity acrylic ester monomer with extremely low skin irritation, it is briefly reported. Principal applications are as a diluent monomer for UV and EB coating materials and inks, and as a modifier in unsaturated polyester resins, acrylic resins and PVC. OSAKA ORGANIC CHEMICAL INDUSTRIES CO.LTD. 

For the radiation rapid cure experiments, appropriate resin mixtures containing oligomers, monomers, flow additives and sensitisers (UV) were applied to the substrate as a thin coating, the material placed on a conveyor belt and then exposed to the UV and EB sources. The time taken to observe cure for each of the samples was then measured on a relative basis. The UV system used was a Primarc Minicure unit with lamps of 200W per inch. Two EB facilities were utilised namely a 500KeV Nissin machine and a 175KeV ESI unit. 

P.T.K. Oldring (Ed.), Chemistry Technology of UV and EB Formulations for Coatings, Inks and Paints, SITA Technology, London, 1994, Vols. I-IV. 

Clearly, UV and EB radiation have a great deal in common, as shown above. However, there are also differences. Besides the nature of interacting with matter, where high-energy electrons penetrate, and photons cause only surface effects, there are issues concerning the capital investment and chemistry involved. 

There are numerous methods of applying liquid systems to different surfaces, and the following sections will discuss some of them. Many of these techniques are used in both UV and EB curing processes. Some are very specific to UV technology, and these will be dealt with separately in connection with that curing method. 

The measurement of the amount of radiant energy delivered by the source is important in order to determine if the equipment operates properly and to ensure that the product will be of required quality. Because of the fundamental difference between UV and EB sources, the measuring methods and instruments are in general different. 

This reference discusses new uses for UV and EB irradiation, the response of polymers to irradiation, and tests related to dosimetry and radiometry, as well as safety and hygiene. It is also fortified with new problems and worked solutions, in addition to useful figures and tables, and appendices with supplementary information on equipment manufacturers, raw materials suppliers, and principles of green chemistry and sustainability. 

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