Material-efficient manufacture of light hardwood products
Ecological forest conversion is increasingly reducing the supply of coniferous wood species (spruce and pine) with low and medium density, which have so far been mainly used by the wood-based materials industry. Substitution with higher density wood has technological disadvantages. The material use of lighter, hitherto little-used hardwoods could contribute to the sustainable supply of suitable wood.
The aim of the planned project is to develop an integrated concept for the material use of alder, lime and birch for the production of innovative light wood materials. In addition, the use of spruce wood from calamity stands is to be tested. The concept involves using as many wood assortments as possible. In addition, by-products that arise during the production of a wood-based material are used for other materials. Logs are processed into rotary cut veneers from which special plywood is produced. The residual rolls from peeling are used together with thinning wood to produce Oriented Strand Boards (OSB) and wood fibre insulation boards. Crown material and thin logs are used to produce particleboard.
Various technologies are being investigated to increase the strengths, hardness and/or durability of the lightweight boards: incorporation of natural fibre or basalt fibre mats in the near-surface layers, use of denser and more durable wood species such as black locust or (modified) beech in the face layers, thermo-hydro-mechanical densification of the plywood surfaces, and the development of a special glue made from lignin-phenolic resin mixtures whose low-molecular-weight fraction penetrates and modifies the wood. By using a formaldehyde-free protein-based binder, panels are also being developed that consist exclusively of renewable raw materials.