Back to list

VOLUME 57, ISSUE 1/2016

The European Timber Regulation (EUTR) Requirements on wood identification in practice

Language: German
Pages: 5 - 11
Authors: Gerald Koch, Volker Haag, Immo Heinz, Hans-Georg Richter

9,00 €

plus VAT
show abstract close

As a contribution to global forest protection the EU Timber Regulation (EUTR, 2010) came into force on March, 2013. Under the EUTR, placing illegally harvested timber and products derived from such timber on the EU market is prohibited. EU operators – those who place timber products on the EU market for the first time – are required to exercise “due diligence” including the correct declaration of the wood species. The clear identification of the timber is also important for the assessment of product properties “consumer protection” as lower-grade substitute timbers are imported at a distinctly increasing rate. In the context of these new challenges wood anatomy provides the most valuable support for practical wood identification and is routinely applied in the daily control of wood and wood products at the Thünen Centre of Competence on the Origin of Timber. The Centre of Competence is the central contact facility for government agencies, timber trade and consumers to verify the species of wood and/or wood products and its origin. In the year 2014 the Centre has executed more than 470 official requests (involving approximately 3,500 specimens) for microscopic wood identification. The requests come mainly from the timber trade sectors (65 %) and increasingly from the German EUTR authorities (24 %). The evaluation of the tested product groups shows, that the requests for the identification of plywood and fibreboards are strongly increased. The identification of the individual veneer layers and cell elements requires a special expertise and the preparation of defined references. The present review article provides detail information on the work and experiences of Thünen Centre of Competence since the implementation of the EUTR.

Renewable wood adhesives based on cross- linkable protein

Language: English
Pages: 12 - 16
Authors: Hendrikus W. G. van Herwijnen, Detlef Krug, Marco Mäbert, Karin Büttner, Matthias Jacob, Markus Pietzsch

9,00 €

plus VAT
show abstract close

Proteins have been used as binders for wood since prehistoric times. In the 20th century they were gradually replaced by “pure chemical” binders. These superior new binders also allowed the large scale production of new wood composites like particle- and fibreboards. Because of the awareness that chemical binders are based on limited fossil resources and because of environmental concerns, proteins made a comeback. Nowadays, effective hybrid systems of proteins with for example phenolic or PAE (polyamido-amine-epichlorohydrin) resins exist. “Full protein” systems, however, still suffer under disadvantages such as inferior moisture resistance and slow reaction. One reason for this poor behaviour is the lack of crosslinks in an unmodified protein system. In order to turn these systems into crosslinkable resins, enzymes can be used. Transglutaminase, for example, links glutamine to lysine, both amino acids readily present in many proteins. Using DNA technology, the enzymes can be adapted to the preferred reaction conditions for the envisioned application, such as the temperature. Furthermore, also the enzyme activity can be increased. The suitability of proteinous resins that are cross-linkable by enzymes was demonstrated by the production of laboratory particleboards.

Powder coating of wood-based materials New lacquers and technologies

Language: German
Pages: 17 - 22
Authors: Klaus Rehm, Jan-Hendrik Nühse, Bernhard Letsch, Raphael Dreier, Raphael Kalt

9,00 €

plus VAT
show abstract close

New ultra low bake powder coatings give the possibility to coat a wide range of wood-based materials and other thermally sensitive substrates. The new powder coatings achieve a high process safety in single-layer and also in double-layer coating technology. The ecological and economical balance of the powder can be further improved by saving in coating material and energy. The technology processes of application and hardening and the measurement of process parameters were examined. Further research is necessary for process and quality assurance. The examination of emissions at the workplace and at coated products could show the ecological harmlessness of the new UNT powder.

Chip loosening factor and chip size distribution during the circular sawing of wood and wood materials

Language: German
Pages: 23 - 30
Authors: Alexandru Blaga, Dan Talpeanu, Thomas Stehle

9,00 €

plus VAT
show abstract close

In the context of this work the main factors for the chip loosening factor and the chip size distribution for wood and wood materials were examined. As experimental tools the focus was set on two categories of saw blades, on the one hand with different tooth shape and on the other hand with different numbers of teeth. The parameters that show a particular impact on the value of the loosening factor are the setting parameters (especially the saw blade position), the tooth shape (flat tooth compared to alternating teeth) and the number of teeth. In addition, the behaviour of the loosening factor for beech and spruce is shown for different cutting directions. The consideration of the chip sizes and shapes also leads to concrete explanations about the origin of the chip product density and thus the loosening factors. With these findings an adjustment of the chip space of the blades can be made, to optimize their acoustic and dynamic behaviour. For this, however, the chip discharge behaviour and the chip space filling level must be examined in the future.

Proof of load-reducing properties of floorings Status of development of a test and simulation method

Language: German
Pages: 31 - 39
Authors: Stefan Schmidt, Andreas Gelhard, Jean-Pierre Mouton

9,00 €

plus VAT
show abstract close

Falls at an advanced age are both an individual and social problem. They can lead to a prolonged treatment with partly irreparable consecutive symptoms such as insecurity, an increase in the risk of falls, as well as directly or indirectly to mortality. Previous approaches to prevent such falls or to minimize their consequences, could only partially achieve success. The aim of the Institut für Holztechnologie Dresden (IHD) is to develop in the course of a preparatory research project, a test method that is able to assess floors and flooring systems in terms of their load-reducing characteristic. By testing method the acceleration-time history in a drop test is recorded and interpreted accordingly. This interpretation allows a qualitatively comparative analysis between different floors. Through the development of an injury criterion an absolute categorization and a description of the risk of injury will be pursued beyond. Accompanying an FEM model is developed to simulate the results of the test method already during the development process of new floors and flooring systems. This enables the efficient development of innovative flooring systems with previously defined properties.

Transparent intumeszent coatings for wood to optimize the fire behavior

Language: German
Pages: 40 - 44
Authors: Torsten Kolb

9,00 €

plus VAT
show abstract close

The use of transparent intumescent coatings on surfaces (i. e. wood) is one possibility to influence the fire behavior of a material. Some substances (mainly resins) being required for the reactive coating were developed in the past at Fraunhofer WKI are currently not available they were exchanged by other resins. The new optimized reactive drying coating can be classified according to the building material class B1. The ingredients of the varnish are separated to two parts, A and B. The best protective

effect could be reached by using a mass proportionately A:B of 2:3. Thermomechanical and thermogravimetric analysis showed that the best foam could be obtained at a temperature between 300 °C and 400 °C. The thermal degradation also starts at this temperature range.

Review: Thermal coating of wood and wood-based materials by open-arc spraying

Language: German
Pages: 45 - 51
Authors: Gerd Paczkowski, Bernhard Wielage, Thomas Lampke

9,00 €

plus VAT
show abstract close

The introduced investigations focus on firmly-adhesive hybrid material systems based on wood-metal compounds, functionalized with ceramic or cermetic coatings depending on the case of application. It is essential to understand the adhesive mechanisms of partially melted metals, affected by a quick cool down and in combination with a wooden cellular matrix material. Another important item focuses on the wear resistance of the compound material, tested under real life conditions, as well as its resistance to harmful organisms, fungi and atmospheric conditions. Functionalizing wooden surfaces serves the purpose of expanding the products life expectancy and expands the possible cases of application of wood into areas originally reserved for other material classes. The market expansion that results out of modified wood products allows new sales opportunities and perspective growth, especially for local wood industries. For companies which applying procedures of thermal spraying a inexhaustible market is opened with new and innovative inquiries of coating in the wood and construction industries.

Back to list