DEVELOPMENT OF A COMMERICAL AIRCRAFT CO-CUREABLE SURFACING FILM WITH IMPROVED UVA-RESISTANCE

Some commercial aircrafts employ a co-curable surfacing film that protects the underlying composite materials from UV-degradation during aircraft manufacturing. However, current state-of-the-art surfacing films are prone to UV-damage, resulting in discoloration, potential paint adhesion failure, and the need for time-consuming sanding or other rework process steps to remove the observable damage. The undesirable discoloration, typically yellowing, can be caused by UV degradation of aromatic components found within the surfacing film and the primary structure resins. Hexcel is currently developing a surfacing film for aircraft composite structures that can address this UV-damage in addition to other market needs. Several surfacing film formulations co-cured with primary structure carbon fiber prepreg were fabricated to obtain composite laminates. These UV-protected co-cured laminates were tested to determine their UV resistance by measuring color changes via colorimetry at different UVA exposure doses. One modification to improve UV-resistance improved it by potentially enough to mitigate rework before the paint application process. Additionally, these surfacing film formulations possess excellent chemical resistance before and after UVA exposure, which is a critical aspect of performance. Eliminating surface preparation operations with UVA-durable and chemically resistant surfacing film supports increasing composite aircraft manufacturing rates for more sustainable air transport.