UV-laser Incisions to Apply Wood-plastic Compositions to Wood Surfaces

Ultraviolet wavelength short pulse laser (UV laser) was used to apply microscopic incisions to wood surfaces. Using the incisions, we tried to improve the physical properties by plasticizing the surface layer by impregnating it with resin. The UV laser can make a large number of perforations without impairing the aesthetic appearance of wood. Focusing on this point, at an incision treatment of 667 holes/cm(2), resin penetration was obtained up to the hole depth from the laser, even with a coating operation under atmospheric or a slightly reduced pressure, and a remarkable improvement in physical properties could be confirmed. When using acrylic resin, the rate of impregnation of solid content was 66 and 53% for sapwood of Japanese cedar and heart wood of Japanese larch, respectively, and the Brinell hardness was improved more than 6 and 4 times, respectively, and the indentation depth in the impact test was decreased less than 1/4 for both specimens. Although a high rate of impregnated solid content could not be obtained, a certain improvement in performance was observed even when a common resin coating was applied for treatment.