Restricted accessResearch articleFirst published online 1969-9
Session 1(c): Basic Techniques—Coding Materials: Preparation,Properties and Application of Luminescent Organic Resins for Letter Facing,Classification and Address Coding
Resins showing delayed luminescence at room temperature were developed by the British Post Office for postal mechanization as they seemed to offer the best combination of low cost, reliability, and freedom from interference. The materials are prepared by polymerizing a small proportion of ‘activator’ into a cyanuric acid-formaldehyde resin. The properties controlled by the ‘activator’ are the waveband required for stimulation of the resin and the waveband and half-life of the delayed luminescence. Properties, methods of application, effect of operational variables, methods of testing, and quality control are discussed in detail.
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