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Hydroxy Functional Co-Curable Polyurethane Films for Composite Surfacing


Title: Hydroxy Functional Co-Curable Polyurethane Films for Composite Surfacing

Authors: Matthew Amick, Eric Orvis, Ted Canterbury

DOI: 10.33599/nasampe/c.23.0131

Abstract: Thermally curable multi-layer film to be used as an in-mold surfacing film for structural composites, methods of its manufacture, and its use in structural composites. Most current surfacing films are based on epoxy-amine chemistry, which has known disadvantages including low UV resistance, limited shelf life requiring cold-storage, and high hardness post-cure requiring aggressive sanding to achieve proper adhesion. The market has asked for a solution devoid of the above-mentioned disadvantages.The solution presented is a thermally curable multi-layer film to be used as an in-mold composite surfacing film, wherein the surfacing film layer comprise an OH-functional polyurethane and a thermally activatable curing agent, which can react with the OH groups at a temperature higher than 120 C. The surfacing film can further comprise optional layers such as an adjustable tack layer and a reinforcement layer to aid in the handling of the material and layup in the composite tooling. This allows for customization of the solution to meet the needs of the production part and process, including for automated tape layup processing. The surfacing film layer together with the optional layers is referred to as a "composite surfacing film".The advantages of this composite surfacing film are the elimination of typical surface defects (e.g., pits, cracks, pinholes) that can occur in the composite molding process by providing uniform film thickness and consistent appearance direct from the tool. Functionally, it can also serve as an in-mold primer providing an integrated layer of outstanding UV protection for the underlying composite. The unique dual function allows for the reduction of steps (e.g., filling/sanding, primer coating application and drying) in composite preparation. This can lead to considerable savings in terms of time and energy.

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Conference: CAMX 2023

Publication Date: 2023/10/30

SKU: TP23-0000000131

Pages: 10

Price: $20.00

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