| 摘要 |
1,227,543. Plywood. WEYERHAEUSER CO. 23 Aug., 1968 [14 Sept., 1967], No. 40477/68. Heading B5L. A dimensionally stabilized plywood panel 10 comprises an inner core 14 of force-resistant material, a face ply 12 and a back ply 16, the grain direction of the face ply being perpendicular to that of the back ply, and the thickness of the plies is such that the panel is dimensionally stable but would not be so if the grain of the plies was parallel. The inner core may be particle board, flakeboard, hardboard or other consolidated board formed by hot pressing fibre felts with or without resin and is preferably 1/6 inch thick. The face ply 12 may be hardwood or softwood such as walnut, birch, oak, pine or elm, while the back ply may be wood or other material such as birch, oak, elm or lauan. Adhesive, such as urea-formaldehyde, is spread over the core and the face and back plies are hot pressed on to the core, the plies being 1/36 to 1/26 inch thick. Sufficient material is then removed from the plies so that the panel is dimensionally stable and not susceptible to warp. The panel may then be glue sized and V-grooved to impart a decorative finish. Fire retardant materials may be included in the core material. |
