Patent GB-1021875-A (GB)
Title: Improvements in or relating to artificial resin bonded chipboard
IPC: B27N3/06
Filed: 1963-01-18
Abstract: An insulating board comprises particles of wood and/or other cellulosic material bonded with artificial resin, the particles being smaller at and near at least one surface of the board than at the centre of the board, the average density of the board being 0.20-0.45 g./c.c. and being substantially uniform along any cross-section of the board.  The particles are conveniently closely arranged at and near the surfaces and more widely separated at the centre of the board, with a comparatively high proportion of air trapped at the centre of the board. The board may be made by allowing the particles coated with or carrying an uncured thermosetting artificial resin to fall in a cascade, jets of air being directed towards both sides of the falling sheet, the resulting loose mat being then subjected to heat and pressure. One or both surfaces of the board may then be treated, e.g. by application of bitumen, veneering, painting coating with a solution, or adhering layer, which may be decorative, of artificial resin material, which may include a carrier, e.g. paper or cellulosic felt.  The layer may be applied to the loose mat before pressing.  The decoration may be applied by use of platens with suitable surfaces, or by applying a decorated paper sheet. The artificial resin material may be thermosetting or thermoplastic, e.g. phenol-formaldehyde or ureaformaldehyde monomer or polymer, or polyethylene, and may comprise the same artificial resin as that used to coat the particles.  The artificial resin layer may comprise a laminate consisting of two or more layers, each layer preferably having thickness 0.005-0.1 inch. The particles preferably have maximum dimension length, 0.5-0.625 inch; width, 0.031-0.125 inch; thickness 0.002-0.030 inch; and minimum dimensions one tenth of these maximum dimensions.  The particles may be dried and may be coated with 5-10% by weight of artificial resin solids, based on the weight of dried particles.ALSO:An insulating board comprises particles of wood and/or other cellulosic material bonded with artificial resin, the particles being smaller at and near at least one surface of the board than at the centre of the board, the average density of the board being 0.20-0.45 g/c.c. and being substantially uniform along any cross-section of the board.  The particles are conveniently closely arranged at and near the surfaces and more widely separated at the centre of the board, with a comparatively high proportion of air trapped at the centre of the board.  The board may be made by allowing the particles coated with or carrying an uncured thermo-setting artificial resin to fall in a cascade, jets of air being directed towards both sides of the falling sheet, the resulting loose mat being then subjected to heat and pressure. One or both surfaces of the board may then be treated, e.g. by application of bitumen, veneering, painting coating with a solution, or adhering layer, which may be decorative, of artificial resin material, which may include a carrier, e.g. paper or cellulosic felt.  The layer may be applied to the loose mat before pressing.  The decoration may be applied by use of platons with suitable surfaces, or by applying a decorated paper sheet.  The artificial resin material may be thermosetting or thermoplastic, e.g. phenolformaldehyde or urea-formaldehyde monomer or polymer, or polyethylene, and may comprise the same artificial resin as that used to coat the particles.  The artificial resin layer may comprise a laminate consisting of two or more layers, each layer preferably having thickness 0.005-0.1 inch.  The particles preferably have maximum dimension length, 0.5-0.625 in.; width, 0.031-0.125 in.; thickness 0.002-0.030 in.; and minimum dimensions one tenth of these maximum dimensions. The particles may be dried and may be coated with 5-10% by weight of artificial resin solids, based on the weight of dried particles.ALSO:An insulating board comprises particles of wood and/or other cellulosic material bonded with artificial resin, the particles being smaller at and near at least one surface of the board than at the centre of the board, the average density of the board being 0,20-0,45 g./c.c. and being substantially uniform along any cross-section of the board.  The particles are conveniently closely arranged at and near the surfaces and more widely separated at the centre of the board, with a comparatively high proportion of air trapped at the centre of the board.  The board may be made by allowing the particles coated with or carrying an uncured thermosetting artificial resin to fall in a cascade, jets of air being directed towards both sides of the falling sheet, the resulting loose mat being then subjected to heat and pressure. One or both surfaces of the board may then be treated, e.g. by application of bitumen, veneering, painting, coating with a solution, or adhering layer, which may be decorative, of artificial resin material, which may include a carrier, e.g. paper or cellulosic felt.  The layer may be applied to the loose mat before pressing.  The decoration may be applied by use of platens with suitable surfaces, or by applying a decorated paper sheet. The artificial resin material may be thermosetting or thermoplastic, e.g. phenol-formaldehyde or urea-formaldehyde monomer or polymer, or polyethylene, and may comprise the same artificial resin as that used to coat the particles.  The artificial resin layer may comprise a laminate consisting of two or more layers, each layer preferably having thickness 0,005-0,1 inch.  The particles preferably have maximum dimensions: length 0,5-0,625 inch; width 0,031-0,125 inch; thickness 0,002-0,030 inch; and minimum dimensions one-tenth of these maximum dimensions.  The particles may be dried and may be coated with 5-10% by weight of artificial resin solids, based on the weight of dried particles.