takes the heat
When the National Fire Protection Association (NFPA) tightened requirements for fire fighters' Self Contained Breathing Apparatus (SCBA), Fosta-Tek Optics Inc., Leominster, Mass., faced an obstacle. The NFPA demanded that SCBA components be able to withstand 10-sec direct contact with open flame and temperatures between 1,5000 and 2,1020F. However, the company, which makes lenses for facepieces, had been using a thermally cured siloxane hardcoat that didn't meet the new requirements.
The NFPA standard requires test subjects to be able to read a standard eyechart from 20 ft away through the facepiece lens after it has been flame and heat tested. The thermally cured hardcoat crinkled, however, impairing visibility. GE Silicones, Waterford. N.Y. Fosta-Tek's supplier, had a UV-cure hardcoat under development that would meet the visibility requirements and resist abrasion, scratching, and chemicals as well.
GE Silicones and Fosta-Tek teamed up to bring the product to market quickly, with GE modifying and producing materials that Fosta-Tek tested in GE's labs. The resulting product adheres to the Lexan polycarbonate substrate without primer and cures in seconds under UV light to a clear, high-gloss finish.