PLYWOOD PRODUCTION METHOD Russian patent published in 1997 - IPC

FIELD: woodworking industry. SUBSTANCE: increased strength of glueing veneer in production of plywood is achieved by improving operations of applying glue to veneer sheets. According to method glue is applied in two stages. At first stage, applied is prime layer of glue with concentration below that of main glue layer, veneer sheet is bent in lateral direction so as to fill with glue of prime layer all cracks occurred during veneer cutting, then veneer sheets with prime layer of glue applied to both surfaces are passed through thermorolling machine, and after that at second stage of operation, main layer of glue is applied to primed sheets of veneer. Bending of veneer sheets in lateral direction leads to closing of sheet cracks and filling it with prime layer glue and when passing through thermorolling machine, prime layer glue partially hardens and its irregularities appeared due to roughness of surface are crushed down. This adds strength to veneer glueing at minimal consumption of glue. In addition, pressure setting of veneer sets is reduced and rejects are minimized. At first stage, prime layer glue is resin with concentration of 30%, and at second stage, main layer glue is resin with concentration of 40%. EFFECT: high efficiency. 1 tbl