Technology for Wood and Natural Fiber-Based Materials

Research Project

Lightweight particleboards made of residues from agricultural plants

In some European countries the wood-based panel industry only has small quantities of timber at its disposal. Increased demand for raw wood on the part of the wood and chemical wood pulp industries as well as the growing utilization of wood for energy means that bottlenecks can be expected in supplies for woodworking and wood processing activities. ossible solutions to securing raw materials in the wood-based panels industry include mobilizing timber from forest areas as yet hardly exploited or completely untouched, the use of waste wood and the use of residues from annual and perennial plants.

Although use of the residues of different agricultural plants as raw material for wood-based panels has already been described in numerous publications, so far these raw materials have been little used in the particleboard industry.

Particleboards have a great importance to the European furniture and interior finishing industries. The mechanical properties of the particleboards are markedly influenced by the board density. The average density of the particle-boards is about 620 kg/m³... 680 kg/m³. The interest of the furniture industry in lightweight boards (with a density of less than 500 kg/m³) has in recent years grown considerably. A joint project supported by the European Commission (DIPP: Development of Innovative Particleboard Panels for a better mechanical performance and lower environmental impact) has as its aim the development of lightweight particleboards for the furniture industry. In particular, shives and plant parts with light parenchymal tissue (stalks) from different agricultural plants (Hemp (Cannabis sativa), kenaf (Hibiscus cannabinus), rape (Brassica napus), sunflower (Helianthus annuus), topinambur/ Jerusalem artichoke (Helianthus tuberosus), maize (Zea mays), miscanthus (Miscanthus giganteus)) are used for board manufacturing.

The stalks were converted into particles by various commination methods and these then pressed to form single- and three-layer particleboards with a density of 200 kg/m³ … 550 kg/m³. Not only were conventional adhesives (urea-formaldehyde resin, binders based on polymeric diisocyanate (PMDI)), used but also acrylic resins and adhesives based on renewable raw materials (tannins, starch).

The mechanical and hygric properties of single-layer boards manufactured without the use of hydrophobing agents were determined (see diagrams) and assessed with regard to the requirements applicable to boards used for interior fittings (including furniture). Results indicate that boards made from hemp shives, sunflower and maize stalks with a density of 400 kg/m³ … 550 kg/m³ meet requirements relating to the transverse tensile strength of type P2 boards (DIN EN 312).

The bending strength of the lightweight particleboards was not yet adequate and during further research work it was planned to increase it by means of a multilayered board structure.

The requirement relating to the transverse tensile strength of the boards bonded with UF resin is already satisfied at a relatively low board density of approx. 440 kg/m³. The bending strength of the boards has been increased by their three-layer structure. The requirement relating to minimum strength for boards for interior fittings (including furniture) has not yet been met. Nevertheless the boards have sufficient bending strength to be suitable for many applications in furniture-making.

 

Project partner
26 partners from 7 European countries are working together in the project.

Co-ordinator: COSMOB
Partners Germany: Fraunhofer-Institut für Holzforschung (WKI)
  Internationaler Verein für Technische Holzfragen (iVTH)
  AGROSYS
  elka-Holzwerke Ludwig Kuntz GmbH
  Maier-Zerkleinerungstechnik

 

Promoted by
European Commission