Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Interzum 2015: WPC furniture with low flammability

04.05.2015

Wood is a popular material in interior design, but its water absorbency limits its use in bathrooms, where natural wood easily becomes discolored or moldy. Fraunhofer scientists and partners have developed a wood-polymer composite material for furniture that is resistant to humidity and has low flammability.

Resource-saving wood-polymer composites (WPCs) are the latest trend in materials for garden furniture and other outdoor applications, especially for terrace decking and also for weatherboarding and fencing panels.


WPC board without (above) and with (below) flame-proofing.

© Fraunhofer WKI

As part of the EU-sponsored LIMOWOOD project, researchers at the Fraunhofer Institute for Wood Research, Wilhelm-Klauditz-Institut WKI in Braunschweig are now collaborating with industrial partners in Belgium, Spain, France and Germany on the development of materials suitable for pressing into moisture-resistant WPC boards for indoor furniture manufacturing.

These boards are composed of around 60 percent wood particles and 40 percent thermoplastic material, generally polypropylene or polyethylene. Both wood and plastic components can be sourced from recycling streams.

The wood component in WPC boards can be replaced by other lignocellulose products derived from the fibrous part of plants such as hemp or cotton, or the husks of rice grains and sunflower seeds. All of these materials are 100-percent recyclable. Moreover, the pressed WPC boards produced by the WKI researchers are formaldehyde-free.

“The controversial question of formaldehyde emissions due to the binder used in conventional pressed wood products is therefore not an issue in this case,” says WKI research scientist Dr. Arne Schirp.

Tests prove low flammability of WPC boards

By choosing appropriate additives, the researchers were able to enhance the fire-retardant properties of their WPC boards. They initially developed their formula on a laboratory scale, using commercially available, halogen-free fire retardants which were added to the wood-polymer mixture during the melt phase.

The first step involved determining the limiting oxygen index of the item under test: this parameter defines the behavior of plastics or wood-filled plastic compounds when exposed to flames. It represents the minimum concentration of oxygen at which the material will continue to burn after catching fire. The higher this value, the lower the material’s flammability. Schirp and his colleagues obtained the best results with a combination of fire retardants such as red phosphorus and expanded graphite.

The limiting oxygen index of WPC boards treated in this way extends up to 38 percent, provided the wood particles they contained were also flame-proofed. By comparison, the limiting oxygen index of a standard wood particle board is 27 percent, and that of an untreated WPC board is 19 percent. Even in a single-flame source test, in which a Bunsen burner is held against the test sample, the treated WPC boards demonstrated a high fire resistance. Even after 300 seconds’ exposure, the boards didn’t catch fire. By contrast, the reference samples – of a standard wood particle board and an untreated WPC board – caught fire and continued to burn.

Another particular feature of the new WPC material is that it absorbs very little water and is thus highly suitable for use in bathrooms and kitchens. Even after being immersed in boiling water for five hours, the material emerges intact, whereas conventional wood particle board was completely destroyed by this test. The only limiting factor on applications of WPC is its inability to support high static loads. But even here, it has been possible to increase its bending strength to a level that far exceeds that of conventional particle board by utilizing a judicious mix of component materials.

Wood-polymer composites can be produced in many ways. The most commonly used processes are injection molding and extrusion, in which the various components – wood fibers, thermoplastic materials, and additives – are melted under high pressure at a high temperature and formed in a continuous mold. Arne Schirp’s team has placed its focus on press technology, because it is the best way to produce boards for use in furniture construction.

“The resulting boards have the same visual appeal as all-wood products and can be glued or screwed together to produce attractive furniture. They’re suitable for all decorative, non-loadbearing elements.” But there are many other applications for wood-polymer composites, including exterior weatherboarding of buildings, the construction of trade-show booths, and interior fittings for houses and ships.

Through their development work, the partners in the LIMOWOOD project aim to fill the gap between the high and low ends of the furniture market, which ranges between expensive and not necessarily ecologically sound materials and cheap products made of particle or fiber board, which at present are mainly produced using formaldehyde-based binders. The WKI researchers will be presenting prototypes of their flame-resistant WPC boards at the Interzum trade show in Cologne from May 5 to 8 (Boulevard, B077).

Simone Peist | Fraunhofer Forschung Kompakt
Further information:
http://www.fraunhofer.de/en/press/research-news/2015/may/WPC-furniture-with-low-flammability.html

More articles from Trade Fair News:

nachricht AchemAsia 2019 will take place in Shanghai
15.06.2018 | DECHEMA Gesellschaft für Chemische Technik und Biotechnologie e.V.

nachricht Insects supply chitin as a raw material for the textile industry
05.06.2018 | Fraunhofer-Institut für Grenzflächen- und Bioverfahrenstechnik IGB

All articles from Trade Fair News >>>

The most recent press releases about innovation >>>

Die letzten 5 Focus-News des innovations-reports im Überblick:

Im Focus: Future electronic components to be printed like newspapers

A new manufacturing technique uses a process similar to newspaper printing to form smoother and more flexible metals for making ultrafast electronic devices.

The low-cost process, developed by Purdue University researchers, combines tools already used in industry for manufacturing metals on a large scale, but uses...

Im Focus: First evidence on the source of extragalactic particles

For the first time ever, scientists have determined the cosmic origin of highest-energy neutrinos. A research group led by IceCube scientist Elisa Resconi, spokesperson of the Collaborative Research Center SFB1258 at the Technical University of Munich (TUM), provides an important piece of evidence that the particles detected by the IceCube neutrino telescope at the South Pole originate from a galaxy four billion light-years away from Earth.

To rule out other origins with certainty, the team led by neutrino physicist Elisa Resconi from the Technical University of Munich and multi-wavelength...

Im Focus: Magnetic vortices: Two independent magnetic skyrmion phases discovered in a single material

For the first time a team of researchers have discovered two different phases of magnetic skyrmions in a single material. Physicists of the Technical Universities of Munich and Dresden and the University of Cologne can now better study and understand the properties of these magnetic structures, which are important for both basic research and applications.

Whirlpools are an everyday experience in a bath tub: When the water is drained a circular vortex is formed. Typically, such whirls are rather stable. Similar...

Im Focus: Breaking the bond: To take part or not?

Physicists working with Roland Wester at the University of Innsbruck have investigated if and how chemical reactions can be influenced by targeted vibrational excitation of the reactants. They were able to demonstrate that excitation with a laser beam does not affect the efficiency of a chemical exchange reaction and that the excited molecular group acts only as a spectator in the reaction.

A frequently used reaction in organic chemistry is nucleophilic substitution. It plays, for example, an important role in in the synthesis of new chemical...

Im Focus: New 2D Spectroscopy Methods

Optical spectroscopy allows investigating the energy structure and dynamic properties of complex quantum systems. Researchers from the University of Würzburg present two new approaches of coherent two-dimensional spectroscopy.

"Put an excitation into the system and observe how it evolves." According to physicist Professor Tobias Brixner, this is the credo of optical spectroscopy....

All Focus news of the innovation-report >>>

Anzeige

Anzeige

VideoLinks
Industry & Economy
Event News

Leading experts in Diabetes, Metabolism and Biomedical Engineering discuss Precision Medicine

13.07.2018 | Event News

Conference on Laser Polishing – LaP: Fine Tuning for Surfaces

12.07.2018 | Event News

11th European Wood-based Panel Symposium 2018: Meeting point for the wood-based materials industry

03.07.2018 | Event News

 
Latest News

A smart safe rechargeable zinc ion battery based on sol-gel transition electrolytes

20.07.2018 | Power and Electrical Engineering

Reversing cause and effect is no trouble for quantum computers

20.07.2018 | Information Technology

Princeton-UPenn research team finds physics treasure hidden in a wallpaper pattern

20.07.2018 | Materials Sciences

VideoLinks
Science & Research
Overview of more VideoLinks >>>