| 摘要 |
A method of applying a smooth thin waterproof coating on engineered particleboards including oriented strand boards, thereby permitting the use of such boards for applications wherein the boards are exposed to moisture, including, for example, foundati on forms, roof sheathing, basement walls, etc. The method of this invention includes applyi ng a thin liquid cementitious coating on a surface of an engineered particleboard having a moisture content preferably less than three percent, wherein the cementitious coating fills t he interstices between the particles and coats the surface. The cementitious coating is then dried and the surface is abraded to receive a thin liquid curable polyurethane coating over the cementitious coating. Finally, the exposed surface of the polyurethane coating is heated to remove surface imperfections and cure the polyurethane coating. In the preferred method, th e liquid polyurethane coating is heated and cured by applying an open flame to the surface of the liquid polyurethane coating which removes surface imperfections, such as bubbles, a nd simultaneously cures the coating.
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