In an effort to make aircraft battlefield composite repairs timely and economical, Bayer MaterialScience has developed a UVA cure technology that allows repairs to be made using the same UVA lights that were originally developed for the automotive refinish industry. At present, structural composite applications such as military aircraft are repaired using traditional two component resins such as epoxy, polyester, silicone, polybutadiene, polyimide and cyanate ester. This UVA cure technology will be the focus of a presentation by Bayer MaterialScience scientists at RadTech UV/EB West, a conference that takes place February 17-18 at the Sheraton Gateway Hotel, LAX, in Los Angeles. The presentation will be given on February 18 at the UV/EB Technology for Aerospace and Defense Applications session by Mike Dvorchak, strategic technology manager, UV cure oligomers and PUDs government programs and Alan Bushmire, senior technician specialist, Government Services Group, Bayer MaterialScience LLC.
The repair by UVA cure technology, company claims, would allow aircraft damaged by ballistic holes caused by ground fire or shrapnel to quickly return to service. Permanent repair would take place at a later time. UVA curable resins that can be utilized for structural composites include: epoxy ester acrylates, polyether acrylates, unsaturated polyesters in reactive thinner, urethane acrylates and NCO bearing urethane acrylates, according to the authors. "Using UVA cure technology, repairs can be made within minutes, instead of waiting 24-72 hours 'cure to fly' that the traditional epoxy system offers," said Dvorchak. "UVA cure technology also has no pot life issues and does not require vacuum bagging to eliminate oxygen inhibition." Dvorchak also noted that one component UVA cure technology does not use harmful volatile organic compounds. He also added that additional research needs to be completed to investigate the use of the UVA resin system to reach performance demands in a high-heat environment and to test the corrosion resistance of conventional aerospace metals with the UVA system.