| 摘要 |
A balsawood core 24 having vessels 8 and axial parenchyma cells 2 extending between opposed major surfaces 18 is provided with a layer of curable resin composition 6, the resin being cured by radiation. The resin may be applied such that in the region of the vessels the resin unevenly fills 16 or only partly fills 10 the vessel. The resin composition may have a viscosity of 1 to 50 Poise, preferably 2 to 8 Poise and an average thickness of 20 to 600 microns, preferably 40 to 400 microns. The curable resin composition may have a coating weight for each balsawood surface of 50 to 300 grams per meter squared, preferably 90 to 120 grams per meter squared. The resin may comprise at least one polymerisable monomer e.g. at least one acrylate or methacrylate monomer and a urethane acrylate monomer, and a curing agent. The resin may be substantially free of solvents or particulate fillers and may be heated when it is applied to the balsawood surface by a roller. The resin may extend 250 to 2500 microns, preferably 750 to 1250 microns into the vessels. The resin may be cured by thermal, ultraviolet or electron beam radiation within 2 to 45 seconds, preferably 10 to 20 seconds from coating. This prevents excessive take-up of resin by the core when it is assembled into a composite material sandwich panel, e.g. having outer layers of fibre reinforced matrix resin material, reducing the cost and weight of the panel. |
