Multilayer chipboard materials - using different binder resins, with interlayer contg. poly:isocyanate binder

摘要

Wood materials, esp. chipboard of Class 100 are made by bonding comminuted ligno-cellulose raw material with a binder under heat and pressure to form multiple layers using different binders, in which an intermediate layer is provided contg. a binder which acts as an adhesion promoter. Improved water-resistance and reduced absorption from use of phenolic resin in outer layers, are combined with high shear and tensile strength from use of aminoplast resin in the middle layer, which also reduces HCHO evolution. Good bonding is obtd., between the alkaline-hardening phenolic resin and the acid-hardening aminoplast resin.