GB785008A - Process for manufacturing veneer panels - Google Patents

Abstract

785,008. Laminates. ELMENDORF, A. June 2, 1954 [July 9, 1953], No. 16280/54. Class 140. A veneer panel is made by applying by heat and pressure to one or both sides of a core of binder-coated uncompacted or loosely compacted ligno-cellulose particles a thin, green, wood veneer coated with an adhesive in excess of the amount required for bonding. The moisture content of the ligno-cellulose particles is 5-10 per cent, and the pressure is effected at 300-350‹ F. initially at 20-100 lb. per sq. ft. to force some of the adhesive between core particles in the region of the core surface, and subsequently at over 100 lb. per sq. ft. to bond the veneer to the core. The adhesive, which may be in powdered form, may comprise urea- or phenol-formaldehyde with, if desired, a filler such as wheat flour. The binder for the core particles may be urea-aldehyde resin, applied by spraying, or by precipitation while the particles are in aqueous suspension. The core particles are as described in Specification 785,007. As shown, a conveyer C carries a succession of cauls 1 on which are placed thin, green veneers 2 beneath a vibrating sieve or screen 3 which distributes adhesive on the veneers and then beneath a vibrating bar or knife 5 which evens up a mass of binder-coated ligno-cellulose fibres placed on the adhesivecoated veneers. The assembly passes beneath a roller 6 which compacts the fibres without bonding them, and under a second adhesivedistributer 7 after which layers 8 of green veneer are superimposed and the resulting sandwiches are hot-pressed. When the veneer layers have flaws such as knot-holes, the comminuted ligno-cellulose particles flow into and fill the flaws.