As delegates gathered for the third European Wood Based Panels Symposium in Hannover on September 12, their own industry was not uppermost in their minds. At the evening buffet reception at the Maritim Airport hotel, it was little over 24 hours since the horrific events had unfolded in New York and Washington and it obviously dominated the conversation.

However, very few delegates were prevented from attending the event which began in earnest on the morning of the 13th. It was formally opened by the secretary general of the European Panel Federation (EPF), Dr Guy Van Steertegem, who requested a moment’s silence before the proceedings began.

The symposium was jointly organised by the EPF and the Wilhelm Klauditz Institute (WKI), supported by the European Federation of the Plywood Industry (FEIC), the European Federation of Fibreboard Manufacturers (FEROPA) and the VTH. There were also a number of commercial sponsors, headed by ExxonMobil, which hosted the Thursday evening reception.

Other industry sponsors were Andritz, Bakelite AG, BASF, Bayer, BHF-Chemie, Büttner, Dieffenbacher, Dynea, GreCon, Huntsman Polyurethanes, Metso, Sapemus Chemie, Steinemann, Siempelkamp and Swiss Combi.

Presentations were made in either German or English, with simultaneous translation, although several delegates expressed the opinion that an ‘international’ conference should be presented only in English.

Frans de Cock set the European scene in his capacity as president of the EPF and said that the participation of the other federations made the symposium a true platform for the whole European wood based panel industry.

He went on to outline the position of the industry as part of the EUR155bn (2000 figures) woodworking sector, of which wood based panels accounts for around 8%, producing 51.1 million m3 in that year.

He said the coming CE marking of panels offered an opportunity to promote the advantages of the industry’s products, as did the use of recycled raw material. Mr de Cock also called for continued development in sorting and cleaning that material to improve product quality.

James Hogg of Jaakko Pöyry Consulting looked at value-added products as the key to sustainable returns.

He subdivided value adding into enhanced panel properties, such as moisture resistance, high and low density, fire resistance and other physical characteristics; and further processing such as cut-to-size, T&G, surfacing, flooring, furniture components and so on.

“Over 50% of the European particleboard and MDF production and some 70% of the production value of the European panel industry are realised in surfaced panel products… through surfacing by the panel manufacturer,” said Mr Hogg.

Low pressure melamine (LPM) was identified as the key surfacing medium used by panel manufacturers, accounting for around half of all value adding surfacing processes.

He added that value adding by processes such as LPM could only pay if the costs of carrying it out were effectively controlled with efficient production technologies because “the bulk of value-added products is largely commoditised and only shows marginally reduced price volatility compared to standard panel products.”

Vicente Leoz Argüelles, head of the construction unit of the European Commission, outlined the implementation of the Construction Products Directive (CPD) on wood based panels, leading to CE marking. He said its objective is the establishment and functioning of the internal market in construction products by means of technical harmonisation. This could be summarised as ‘creating a level playing field’ for all construction-related panel products in the EU.

It is expected that the use of CE marks will be established by the end of next year, having been delayed to some degree by the preparation of the fire standards package and the fact that the procedure for classifying products without further testing is still under preparation.

Continuing on the subject of the fire resistance of wood based panels, Ms Birgit östman of the Swedish Institute for Wood Technology Research (Trätek) said that results from a number of test programmes, including a joint test project by EPF, FEIC and FEROPA, had shown that Euroclasses D and DFL (EN 13968) had been verified for most wood based panels.

Ms östman also said that panel thickness and density are decisive for the FIGRA (fire growth rate) values and that the project had laid the scientific foundations for classifying the fire performance of panels without further testing.

Returning to the subject of CE marking, Kris Wijnendaele of the EPF set out to give practical assistance to manufacturers and users of panels in achieving CE marking through the use of EN 13986 and the underlying European standards. He also covered the kind of information which would need to be included in the mark.

Session two of the symposium covered the area of production and control technology and was kicked off by Ralf Schäckel of GreCon, who presented ‘New systems for on-line moisture measurement’. After outlining the established systems for laboratory measurement of samples and their various advantages and disadvantages, Mr Schäckel described his company’s on-line, non-contact measuring systems ‘IR 3000 WBPi’ and ‘MWF 3000’. The former is infra-red based, while the latter is a microwave resonance based system. He also outlined the principles of accurate moisture measurement and presented some applications of the technology he described.

Mat forming was the subject of Dr Michael Schöler of Siempelkamp’s R&D centre. He traced the history of particle mat forming from the earliest single layer boards of the early 1940s through individual forming box systems to continuous formation, albeit still into forming boxes (and the spaces in between them! – this material was then recycled).

When three layer particleboard with distinctly different material in surface and core layers was commonplace, a new way of forming had to be found.

“An important pre-requisite for continuous mat formation without forming boxes and the problems arising therefrom was the development of pre-presses,” said Dr Schöler. The first one was used in 1946 and the first continuous mat forming system based on a belt design came in 1949 in Germany, he said.

“By the mid-1950s, the basic design of all important mat forming systems, which are still in use today, had been completed,” said the speaker.

He outlined these and went on to describe the development of mechanical and air graders and the various types and combinations offered by Siempelkamp today.

Sandvik has been involved with the wood industry for 100 years this year, first as a supplier of belt conveyors, explained the company’s Jan-Ola Jonsson.

Today, of course, the company is a major supplier of belts for continuous presses; such belts were first used in the Bison system of single opening presses with a continuous steel belt to carry the mat through the press, in 1957.

“Towards the end of the 1960s, Sandvik pioneered a continuously operating double belt press and this design principle is still used for continuous presses,” said Mr Jonsson.

The Küsters continuous press, using steel belts, was first introduced in 1977 at Spano of Belgium. In 1984, Siempelkamp followed with the ContiRoll and in 1990, Dieffenbacher introduced its Conti-Panel system, he said.

Sandvik has developed micro-alloyed dual phase carbon steels to avoid heat treatment for welds and high-strength precipitation hardened steel belts for continuous production of thin panels. More recent developments have included belt repair and reconditioning systems which were also outlined in the presentation.

Dr Christopher Skinner of Huntsman Polyurethanes looked at the impact of moisture content, temperature, wood species and resin chemistry on the primary product distribution of novel isocyanate based binders for OSB. The objective was to increase production rates and Dr Skinner claimed a 20% increase using his company’s Suprasec 1482 fast cure pMDI (polymeric diphenylmethane diisocyanate) binder.

The development of OSB has been markedly different in North America and Europe and Harald Fried of Pallmann delved into the background of this product in both continents and its development since its introduction in 1978.

He outlined Pallmann’s developments in flaker technology, including an analysis of ring versus disc flakers, as well as debarkers, and looked at future applications for OSB.

These uses, he suggested, include residential flooring, wall sheathing and roof decking, king size panels and increased use of surface coating for such applications as concrete form work.

“The challenge now will be for manufacturers to develop value-added OSB, cultivate export markets and change the perception of OSB as a mass produced high quality commodity,” concluded Mr Fried.

Volker Thole of the WKI looked at the plastification of the fibre mat in relation to the density profile of MDF and concluded that the elastic and plastic properties of the mat can be described with a mechanical model of spring rigidity. The major parameters influencing hot pressing were found to be mat temperature and moisture and the degree of curing of the binder.

Staying on the scientific track, Dr Heiko Thömen of the University of Hamburg presented a computer simulation of continuous hot pressing as a tool for industrial and research applications.

This presentation was followed by Dr Christian Boehme’s paper on the problems which may arise in testing the internal bond (IB) of OSB after storage in boiling water, as required in EN 300.

As a result of his work, Dr Boehme has suggested modifications to the standard for OSB3 and 4.

The session was concluded by Detlef Krug of the institute for wood technology in Dresden (IHD) who reported on his work to gain a significant improvement in the swelling characteristics of MDF by utilising higher pulping pressures and longer pulping times. His work, he said, has implications for the extension of existing applications of MDF as well as in developing new applications.

At the end of this first day of presentations, ExxonMobil transported the delegates by chartered train to dinner and musical entertainment in a restored railway station in Hannover, which is now classified as a monument (and was even before the panel industry went there!).

The second day of the symposium opened with a session on production and finishing technologies, with Klaus Radzimanowski taking the platform for the first paper.

He presented the work of Schenkmann & Piel on a superheated steam dryer for fibre, saying that the system has advantages over hot air systems in that the specific heat and heat transfer are higher in its closed-circuit inert atmosphere.

“The process steam and the steam evaporated from the fibres can be utilised for example for pre-heating the chips, heating of air for air grading and conditioning of grader air to control the wet bulb temperature,” asserted Mr Radzimanowski. He also said that approximately 60-80% of the heat energy required for drying can be recovered.

The ‘hot topic’ in continuous pressing at the moment is, in fact, cooling and Gottfried Bluthardt of Metso Panelboard talked about the technical and technological advantages of board cooling in the Küsters press.

Sharing the platform was Marius Barbu, a well-known face at technical conferences appearing at this symposium in his relatively new role with MDF-Hallein in Austria. The mill started up in April 2000 with a 28.7m Küsters press, later extended to 35m, with a cooling zone, so Dr Barbu was able to give a first-hand account of the cooling technology in practice. He said advantages included lower gas pressure in the mat, press capacity increases of 10-20%, improved IB, and reduced panel shrinkage and formaldehyde emissions. Energy savings and reduced fire risk were also achieved.

Dr Stephan Friebel of the WKI reported on work to develop a ‘recipe’ for MDF and particleboard panels suitable for powder coating. This has been achieved on a small scale and the WKI is looking for partners to scale up the technology.

In a linked-theme presentation, Kris Buysens of UCB Chemicals brought delegates up to date on developments in UV-curable powder coatings and their properties, claiming both technical and economic advantages for the system.

Staying with coating technologies, Ali Valhaus of Treffert Group talked about high performance coatings (HPCs). See WBPI Oct/Nov.

Turning the clock back to gain advances in sanding technology could be described as the theme of Riccardo Ferrari of Imeas of Italy. He described the company’s new application of the old technology of cross-belt sanding commonly used in the furniture industry more than 26 years ago.

The cross-belt sanding head is positioned after the conventional eight-head sanding line.

“Cross sanding eliminates longitudinal lines and other imperfections,” said Mr Ferrari. Speed was always the problem with the old systems, but Imeas has developed a system which can run at a pace to match continuous presses – 50 to 60m, so far.

Session 4 of the symposium, entitled ‘actual challenges’ was started off by Panagiotis Nakos of ACM Wood Chemicals. He presented ACM’s work on the production of wood adhesives from pyrolysis oils. “Our target was to identify new resins from other than petroleum-derived sources, to reduce demand on fossil fuels and promote sustainable development.

“We also wanted to reduce resin cost by introducing raw materials of a lower cost than phenol but obtain the same or enhanced quality as conventional resins.”

So far, only partial substitution (up to 50%) of phenol has been achieved but the boards produced fulfilled all requirements, said Mr Nakos.

“It is well known that thin particles are key to high quality boards,” began Romeo Paladin of Italian company Pal srl, who pointed out that the quality of raw material has been decreasing with lower quality fresh wood, and recycled wood presenting new challenges to board quality. He analysed the problems which can occur in chip production and suggested a method of refining the chips for particleboard to achieve higher quality boards.

This involves producing long chips, separating them into fractions and refining each fraction separately with the correct technology. Training operators to be aware of chip quality was also important, said Mr Paladin.

Eight installations using Pal’s chip technology have been made so far, including the particleboard mill of Fantoni in Osoppo, Italy (WBPI Aug/Sep).

Rounding off this third European Wood Based Panel Symposium, Kelvin Chapman of MDF Tech, New Zealand, presented his paper on ‘A new approach to MDF refiner operation’.

His approach involved developing a mass-energy balance over an MDF refiner to identify conditions influencing refiner stability and affecting fibre quality. He said it determines the steam flow in the blowline and can be used to optimise the blowline configuration.

Mr Chapman said the system had been successfully used in investigating blowline resin blending in 16 MDF plants and has lead to significant improvements in blowline resin effectiveness.

“This technique allows you to look at the MDF refiner in a completely different way and gain a new understanding of how it operates,” said Mr Chapman.

Dr Rainer Marutzky, head of the WKI, brought the symposium to a close and invited delegates to attend the next event in 2003. He said that the presentations had offered a mix of practical experience and theoretical models to show how to optimise and improve the panel making process, as well as one presentation which was pure advertising. “I suppose we have to live with that!” exclaimed the professor.

This is often a problem at conferences and symposia and certainly those who use such a presentation purely to promote their own products often do little to further their own cause in the eyes of their audience.