Chipboard moulded with isocyanate-impregnated layers - giving strength appearance and water-resistance

摘要

Between 1 and 30 (3-10) layers impregnated with 10-300 (40-150) wt.% organic isocyanates opt. diluted with solvents, are placed on one or both sides of the concns.-resin treated cellulose or lignocellulose particle layers before hot-pressing to form chip-board. The impregnated layers are of cellulose or liquocellulose, e.g. paper, with wt. of 40-1000 (40-150) g./m2., or may be non-woven or woven fabrics of inorganic and/or organic materials. The outer layer consists of 3-100 (10-15) um PE film covered with opt. printed paper and/or wood veneer, or consists of metal foil, e.g. al. The isocyanate vapours penetrate the particles during pressing and react with the formaldehyde concns. resins to form a polyurethane binder, giving increased mechanical strength, improved appearance, less thickness increase after pressing and reduced swell in water.