摘要 |
<p>The invention relates to wood-fibre semi-finished products, consisting substantially of compressed wood fibres which are coated with thermally-hardened condensation resins. The degree of sealing of the wood fibres consists of between 30 and 60 % solid resin in the form of condensation resin mixtures or mixed condensation resins (copolymerisates) in relation to 100 % dry fibres. The solid-resin proportion of melamine formaldehyde resin as a condensation resin is a maximum of 45 % in relation to dry wood and the solid-resin proportion of phenol-formaldehyde resin as an additional condensation resin is less than 15 % in relation to dry wood. The inventive wood-fibre semi-finished products are also dimensionally stable under variable climatic conditions, a fact which can be attributed to the coordinated chemical and physical interaction between the wood fibres and the sealing agents in the form of special condensation resin mixtures or mixed condensation resins (copolymerisates). The wood-fibre particle boards which are produced from these semi-finished products have both interior and exterior applications.</p> |