Ultra-violet curing

Nwabuzor, A.O., Okoli, O.I. Preliminary assessment of the ultra violet curing of composites manufactured by the resin infusion between double flexible tooling process. Polym. Compos. 27, 417 24 (2006)... 

Shields, J. (1977) Evaluation of an ultra-violet-curing structural adhesive. Adhesion 1, Allen, K. W., Ed., Appl. Sci. Publ., London, Chapter 11. 

Radiation cure system. Other addition reaction cure systems that have emerged in recent years are the ultra-violet (UV) and electron beam (EB) radiation cure systems. The development of these systems has been prompted by the ever-increasing need for fast cure rates and low cure temperatures. The U V cure system... 

Unsaturated polyester finishes of this type do not need to be stoved to effect crosslinking, but will cure at room temperature once a suitable peroxide initiator cobalt salt activator are added. The system then has a finite pot life and needs to be applied soon after mixing. Such a system is an example of a two-pack system. That is the finish is supplied in two packages to be mixed shortly before use, with obvious limitations. However, polymerisation can also be induced by ultra violet radiation or electron beam exposure when polymerisation occurs almost instantaneously. These techniques are used widely in packaging, particularly cans, for which many other unsaturated polymers, such as unsaturated acrylic resins have been devised. 

Irradiation by Ultra-Violet or Visible Light. Systems of this nature comprise materials such as acrylic resins in which a photo-sensitizer (for example, benzophenone) is incorporated. On exposure to ultra-violet radiation the photo-sensitizer dissociates into free radicals which then catalyse polymerization of the acrylic material. The reaction is controllable and takes place within a few seconds the ultra-violet radiation may be directed and focused so as to obtain cure precisely where needed. Products like these are used to retain coatings, wiring, and other components in the assembly of electronic goods. 

The Curing of Coatings with Ultra- Violet Radiation, D8667 G.LVTioxide of Canada, Sorel, P.Q., Canada. 

The area of ultra-violet curable resins has undergone considerable growth during the last 15 to 20 years. Useful resin systems which can be cured by ultra-violet light initiated free radical mechanisms can be classified as follows ... 

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. 

Specificallly for ultra-violet light-cured glass-metal joints Anaerobic adhesives on threaded fasteners... 

The compound has functional groups that support dimerization type crosslinking and cationic polymerization upon UV exposure (A, = 300—360 nm).. Photodimerization of the chalcone-epoxy compound was confirmed by UV-visible and IR absorbance changes of the C=C double bond of the chalcone unit. Additions of small amounts of onium salts will also photoinitiate cationic polymerization of the epoxy groups present in the above chalcone-epoxy compound by exposine to UV. This ultra-violet light cured chalcone-epoxy compound was reported to possess excellent thermal stability and compares well with conventional UV-cured Bisphenol A type epoxy resins. (see Chapter 3)... 

The layman s term for the time/lemperature related molecular cross-linking process - known more correctly as polymerisation - which occurs when a thermoset resin changes from the typically viscous liquid to the solid state. This cure process is normally also promoted following chemical activation by a catalyst - or often called, hardener -addition. Other chemical accelerators may be added by the resin manufacturer, or alternatively added to the resin immediately prior to the catalyst addition. Cure can also be activated in other ways, such as by the influence of ultra-violet radiation. No by-products are formed during the formation of these long molecular cross-linked chain links. 

Khan, M.A., Bhattacharia, S.K., Kadta-, M.A., et aL Preparation and characterization of ultra violet (UV) radiation cured bio-degradable films of sago starch/PVA blend. Carbohydr. Polym. 63, 500-506 (2006)... 

Radiation curable adhesives Inclusion of a photo initiator in some one-component-type resins allows initiation of cure by ultra-violet or visible light, or by an electron beam. 

Rehabilitation of pipes by CIPP, with thermoset polyester resins and polyester felt, usually requires satisfying predetermined specificalions for both materials and installation. With CIPP, a tubular hner is saturated with a resin, which is then inserted into the damaged pipe and cured via heat and/or ambient or ultra violet light. The pipe defect is initially identified and located, usually by means of a closed circuit television survey or PIG. The resin saturated liner is then inserted into the pipe and inflated against the wall of the pipe by air or water pressure. The resin cures and hardens into a smooth structure and a new composite pipe is created within the old pipe. The materials used to manufacture the components are chosen to suit the function of the repaired pipeline. The combination of the hner, resin, the method of installation and the chosen curing method will determine the overall quality of the end product. 

Curing Depths of Materials Polymerized by Ultra-Violet Light",... 

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