| 摘要 |
665,672. Plywood sheets; plugging knot holes &c. WELCH, A. R. Dec. 24, 1947 [Aug. 9, 1944], No. 34237/47. Classes 145 (i) and 145 (ii) A plywood product comprises at least one outer ply having cracks, fissures or imperfections in its outer surface, covered with a mixture of synthetic thermosetting resin and discrete wood particles of sanderdust and/or sawdust in the form a layer of sufficient thickness to fill the cracks &c. and present a smooth outer surface, the said layer being bonded to the ply under heat and pressure by the conversion of the synthetic thermosetting resin. A plywood product is made up of a central ply 12<SP>1</SP> and two outer plies 10<SP>1</SP> and 16<SP>1</SP> bonded by suitable adhesives, the latter plies having their grains running at right angles to the grain of the central ply and arranged so that the cracks, caused by peeling the plies from the log and flattening them, are outermost. A mixture of sanderdust and sawdust and synthetic resins is bonded to the exposed surface in the form of a layer 24<SP>1</SP> by a hot press. Surface defects in plywood may be filled with the mixture and a further layer bonded on top. |
