Ultra-violet curing light

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 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 ... 

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)... 

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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