Radiation-cured coatings discussion

Epoxy acrylates are also commonly used as oligomers in radiation-curing coatings and adhesives. However, their name often leads to confusion. In most cases, these epoxy acrylates have no free epoxy groups left but react through their unsaturation. These resins are formulated with photoinitiators to cure via uv or electron beam (EB) radiation. The reaction mechanism is generally initiated by free radicals or by cations in a cationic photoinitiated system. The uv/EB cured epoxy formulations are discussed in Chap. 14. 

The preparation of several propargyl monomers and diacetylene polymers. and their initial characterization as radiation cured coatings for corrosion protection is discussed in the present report. 

The utility of iV-vinylformamide (NVF) as a functional monomer can be significantly expanded by base catalyzed addition of the amide nitrogen to Michael acceptors to generate novel derivatives with differentiated properties. Scope, synthesis conditions, reactions, and structure/property relationships for a series of alkyl 3-(iV-vinylformamido)propionate Michael adducts and related 3-(N-vinylformamido)propionamides prepared on subsequent transamidation with alkanolamines and diamines are presented in the context of radiation cure coatings. Mechanistic details of the catalysis of the Michael addition reaction are discussed and rationalized. 

An up-date of the status of EB curing of carbon fiber composites was presented by A. Berejka. Developments proven successful for aerospace applications are now being seriously scrutinized for automotive use. The diversity of proven uses of radiation grafting for uses in batteries, porous film and non-woven filters, and release coated films and papers was also presented. Opportunities for use of grafting in biomedical applications, composites technology, and fuel cell membrane development were also discussed. 

Radiation-induced curing of plastic coatings has been discussed,8 and radiation-induced polymerization in the solid state reported.87 The radiation chemistry of epoxy-containing electron resists88 and polycondensation induced by ionizing radiation in the urea-formaldehyde system88 have been described. Radiation-induced copolymerization of the following pairs of monomers has been achieved ethylene-hexafluoropropylene,80 tetrafluoroethylene-propylene,81 tetrafluoroethylene-hexafluoropropylene,82 hexafluoroacetone-a-olefins,83 MMA-di- and tri-methacrylates,84 styrene-acrylonitrile,85 buta-1,3-diene-acrylonitrile,88 and acenaphthylene-vinylcarbazole.87... 

Among the most successful of the new radiation-curable silicone coating systems are compositions Incorporating cycloaliphatic epoxyfunctional silicone polymers with compatible iodonlum salt photocatalysts (1 - S ) The syntheses, structures, UV cure response, and other properties of these materials and some of their derivatives and monomeric homologs are discussed In the balance of this chapter. Their specific application for release coatings has been described In great detail elsewhere (5.6 > and Is not the subject of this paper. 

In this example radiation euring is eompared with several other eoating teehnologies, sueh as solvent-based two-eomponent polyurethane, acid curing, nitrocellulose and water-based coatings. In the application discussed here, a specific customer use was defined as performance application of 1,000 wooden front doors. 

The development in the 1960s of extremely rapid methods of curing these coatings with ultra-violet and electron beam radiation, has led to an extension of the chemistry to compositions based on resins and monomers containing acrylic unsaturation. These coatings will also be discussed in this chapter. 

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