The European Panel Products Symposium (EPPS) has become an established annual event since the BioComposites centre staged the first conference in 1997. It has always been a forum for presenting the latest scientific advances by universities and research organisations and retains the lead in that area, while at the same time adding presentations on marketing and machinery to the programme in recent years.
An extensive poster display in the coffee lounge gives the opportunity to air presentations which did not make it onto the conference programme or indeed to elaborate on some of those which did. The accompanying supplier exhibition gave companies the chance to discuss their products in their own booth and exhibitors included F-Stop from Belgium, McCarthy Products from the US, Würtz from Germany, TECO PFS Corporation and GreCon.
Main sponsors of this year’s event were Willamette Europe, TRADA Technology, F-Stop, Dow Chemicals, Metso, Kronospan, ACM Wood Chemicals, CAE, Habasit, Dynea, Nexfor and WBPI.
Attendance was a little disappointing, with two main factors being blamed. First was the world political situation following the terrorist attacks in the US on September 11, resulting in some delegates cancelling their plans to attend, even from within Europe. Second was the generally depressed economic climate experienced by panel makers.
Those who did attend were presented with a varied programme by 24 speakers from many countries and professions. The conference was divided into five sessions over two and a half days.
Dr Manfred Dunky from Austria, who is with resin manufacturer Dynea, gave the keynote address entitled ‘Wood based panels: an interdisciplinary approach’. He pointed out that Dr James Boulton, organiser of the first EPPS, said there were a lot of challenges and questions to be taken up by the industry, listing new raw materials, new adhesives/additives and new processes. “It is still much the same,” he said.
Dr Dunky pointed out that the production of wood based panels requires input from various sciences. These include wood anatomy, physics, technology and chemistry; the chemistry of adhesives; processing technology; as well as ecological and economic sciences.
“Only the interdisciplinary cooperation of the various individual sciences can describe and optimise wood based panels and guarantee their best possible performance,” he said.
From forestry the industry needs a sustainable supply of sufficient raw material at the right price, he added, also mentioning the increasing role of recycled wood.
Opening session one, ‘Process control and technology’, Dr Eugenia Dessipri of ACM Wood Chemicals presented a paper on the use of FT-NIR spectroscopy for on-line monitoring of formaldehyde based resin synthesis. This is no pure science investigation, but a way of answering every day questions about the synthesis of resins.
The results of this research are intended to enable the on-line analysis of the pathway followed during formaldehyde-based resin synthesis in less than a minute. In industrial situations, this is intended to provide reproducibility and improve overall resin quality. The methodologies are also being applied to laminating papers impregnated with resin to determine their usability with ageing.
The system is known as GNOSSI, which, apart from meaning knowledge in Greek, stands for ‘general on-line non-destructive spectroscopic interpretation’.
In the never-ending quest for efficiency, the subject of pre-heating the mat prior to pressing in an MDF plant is, as they say, a hot topic.
Celeste Pereira of the University of Porto, Portugal, described the modelling and simulation of HF pre-heating and claimed several advantages over conduction, including more uniform heating throughout the mat, lower press platen temperatures, constancy of resin formulation and reduction of post-curing time. “The industrial application of HF heating, however, is not yet well optimised and controlled,” said Ms Pereira. “A dynamic model of HF heating has therefore been developed in order to allow optimisation of the heating process.”
Continuing the subject of pressing, Dr Heiko Thoemen of the University of Hamburg, Germany, said: “A fundamental understanding of the pressing process is essential for optimising production speed, costs and energy consumption as well as manipulating board properties, and for the development of new technologies and products.”
He thus investigated the physics of hot pressing by means of simulation in two major areas: the importance of different heat transfer mechanisms and how they vary over space and time; and the contributions of air and water vapour to internal gas pressure and how the proportion of these two components changes over space and time.
Not all the presenters of papers were career scientists and Kerry Quilter of panel maker Nexfor provided proof of that with his paper ‘Discussion on the effect of moisture and heat transfer during continuous MDF pressing’. “We are trying to produce a good surface for paper overlay or painting and a board that is strong as a table top or an item of furniture,” said Mr Quilter. He pointed out that an ideal density profile of MDF shows a high density at the surfaces and a lower core density – the typical ‘M’ profile – and that there is a definite correlation between core density and internal bond strength (IB) in MDF as well as in particleboard.
Mr Quilter described the five zones of a continuous press. Zone 1 is de-aeration, zone 2 is where the higher density surface layers are formed, at zone 3 pressure is reduced to improve heat transfer into the core of the board. In zone 4, pressure is again increased to raise core density and achieve final thickness; zone 5 is for pressure release or de-gassing.
But it is not that simple, said Mr Quilter, pointing out that the variation in density profile from the mat’s centre to its edges “makes the board producer’s job more difficult, or at least interesting.”
He concluded that it is impractical to install sufficient on-line density profile meters to monitor the whole of the board but said: “The essential indicators for product quality at this stage are thickness control and moisture content. Continuous moisture indication allows the press operator to detect possible variations and then closely monitor the press outlet for thickness problems.”
After lunch, delegates heard two more papers before spending time studying the poster session and exhibitors’ booths. The first paper was given by Armin Lingen of German company ATR on the company’s Statistical Process Modelling and Online Quality Control – SPOC for short.
He claimed that this system, having been in use for over three years, can make significant savings for board producers in areas such as wood and glue consumption, with online quality predictions on IB and modulus of rupture (MOR) being made with an accuracy of about 95%, while average apparent density is predicted with a 95% accuracy rate. “With SPOC you can reduce expensive safety margins or improve the quality itself,” said Mr Lingen.
Rounding off day one, Martin Ohlmeyer talked about hot stacking of panels as an important tool for improving panel quality, saying that the last research into the subject was carried out some 30 years ago and that glue systems have changed dramatically since then.
He and his colleagues carried out experiments on panels with a variety of resin systems and found that hot stacking generally led to improved IB and thickness swelling (TS) characteristics, although the optimum stacking temperature varies with the glue system used.
Session 2: ‘Resins, additives and raw materials’, was opened by Dr Chris Skinner of Huntsman Polyurethanes who spoke on the production of 100% MDI bonded OSB using a combination of internal and external release systems appropriate to continuous pressing.
Many mills using MDI have relied on using other resin systems in the surface layers to prevent adherence to the press plates/belts.
Dr Skinner described a system using a ‘self-releasing’ pMDI (Suprasec 1454-57) developed by Huntsman, in combination with an external release agent (PAT – 7399) developed by the Würtz company.
“The release system needs excellent thermal stability, especially with press temperatures tending to rise,” he said. “It also must not impact belt life or the panel surface.” The above combination was found to meet these requirements with economic advantages over MUPF/MDI systems, he said.
Continuing the OSB bonding theme, Dr Frédéric Pichelin of the Swiss School of Engineering for the Wood Industry, talked about high moisture tolerant adhesives.
These, he said, were required because superior board properties could be achieved in boards manufactured at higher moisture contents (20-30%), largely due to wood plasticisation. Tannin based adhesives were used and so far are the only ones found to give good results at very high moisture contents.
Forintek Canada Corporation is a prolific research body and Martin Feng reported on some of its latest work, namely the non-destructive detection and measurement of UF resin distribution in MDF as a key to high quality boards at low cost. The resin was labelled with a copper ion labelling agent which was then detected by x-ray fluorescence spectrometry.
Professor Roffael of the University of Göttingen reported on the influence of moisture content (MC) on the formaldehyde release of particleboard and MDF bonded with formaldehyde based adhesives. Among his results, he found that increasing MC in acid-cured UF and MUF resins increases the level of extractable formaldehyde, while modification by melamine decreases the level.
Back to OSB, Dr Martin Ansell of the University of Bath reported on a project to establish the influence of strand size and shape on MOR and MOE by image analysis.
He discovered that panels manufactured from long, slender strands possess the highest MOR and MOE values and that increasing the height of delivery of strands increases mis-orientation and reduces mechanical properties.
Session 3: ‘New products and markets’ was opened by Dr Marius Barbu of MDF-Hallein who shared his experiences with operating a Metso (Küsters) press with cooling section. He found this system can produce boards with higher moisture contents, resulting in faster production speeds or better board properties and lower emissions at the press outlet.
One of the problems in the external use of OSB relates to its propensity to take up moisture leading to swelling, loss of IB strength and possibly decay.
Dr Mike Hale of the University of Wales, Bangor, found that increased pressing time and temperature can produce a more stable and decay resistant board without excessive use of preservative chemicals.
He suggested this could also lead to increased opportunities for OSB as an alternative to preservative treated plywood and solid timber for many exterior construction applications. Dr Hale is seeking support for further research in this area.
Improved durability and dimensional stability are key goals for panel manufacturers, as Dr Dennis Jones of SHR Timber Research of the Netherlands, pointed out.
He reported on various methods of chemical, thermal and enzyme modification of raw materials as one approach to this area, and on the establishment of a ‘thematic network’ in Europe. This network is designed to coordinate developments in this field across Europe and is funded by the EC. To find out more, contact www.woodmodification-network.org.
John Wadsworth of international consultancy Intermark asked whether success in the international wood based panel industry was due to technological magic or marketing muscle.
He jokingly suggested that since the technologists produced a flat sheet in 1957, the rest had been down to marketing. “Panel products are everywhere,” he pointed out. “In our homes, our shops – where they have lead to a revolution in retailing – in our offices, even in particleboard coffins!
“But what have we gained? Do our customers respect us for it? Do they want to pay for it?” He said the global value of the panel products market was around US$16-22bn and these products therefore still have a long way to go, adding: “Many companies have a turnover in excess of this figure.”
The industry spends all its time competing with itself and undervalues its products, he suggested, saying: “Price is the blunt weapon used by the industry.” He said the mega-sites (mainly in Europe so far), global networks and the approach of big companies to distribution are part of the ‘marketing muscle’ of the industry.
In process efficiency, Mr Wadsworth saw operators investing in panel handling, emission control and wood handling in the future, while in OSB, he expects more emphasis on continuous pressing, especially in North America which has far fewer continuous presses than Europe.
“There is a need for cost improvements in both capital costs and running costs,” he said. He foresaw large plants for standard products and smaller plants for speciality products and value adding.
“Remember to sell the benefits. The bridge between technology and marketing in future will become design.”
After an enjoyable conference dinner at the end of the second day, delegates assembled on Friday morning for the fourth session of EPPS 5: Environmental issues.
Nick Jones of Compak Systems in the UK asked “Why particle is size important to wheat straw based particleboard?” He pointed out that in wood based particleboard, it is normal to remove fines and dust as they reduce the IB of the panels. However, his research has found that the reverse is true for wheat straw based product.
“By assessing alternative raw materials using a process based on wood, you may miss an opportunity. You may need a significant departure from wood based panel systems,” concluded Mr Jones, who said that the process of particleboard production must be matched to the unique characteristics of each raw material with respect to the grade of product that is to be produced.
Romeo Paladin, managing director of wood recycling specialist Pal srl of Italy, outlined his company’s system for making the best use of recycled wood by careful cleaning of the raw material before and after drying and separating it into separate chip streams which are processed according to their specific characteristics.
He said that Pal equipment, such as the Tiger crusher, Dynascreen, Dynasifter wind sifter and the eddy current separator and chip dry cleaner and other specialised machinery can be combined in a specific way to produce high quality boards from what he calls ‘the urban forest’.
Kronospan is the ‘local supplier’ of panel products to the Llandudno area, producing 92,000m³ of panels a month at its Chirk site in north Wales.
Joe Martoccia, deputy managing director of the factory, talked about Kronospan’s experiences in using recycled urban wood as a raw material in cooperation and collaboration with Pal and with its own tooling manufacturer. The factory also uses FSC accredited fresh wood as part of its ‘environmentally responsible’ approach. Mr Martoccia admitted to cost advantages for the panel manufacturer in using this material, but said: “You can’t keep those cost advantages these days; you have to pass them on to the customer.”
His factory is using some recycled particleboard from its furniture customers by utilising return capacity on transport. However, he did point out that there are some problems with customer perceptions concerning particleboard made from urban wood and concluded: “We have to tackle any consumer and client objections .”
The final session, number 5, was entitled ‘Fundamental properties’.
John Alexander of Jeld-Wen, standing in for his US colleagues unable to travel to the UK, gave a presentation on the effect on structural performance of MDF of raw material, refiner pressure and resin formulation.
The team found juvenility of MDF fibre has a significant effect on structural properties, with mechanical properties increasing with fibre juvenility. However, the most influential factor is refiner pressure.
Dr Mark Irle of the Forest Products Research Centre, Buckinghamshire Chilterns University in the UK, ended the conference with his paper on visualisation of cell wall collapse caused by hot pressing of wood particles. He and his team pressed single wood particles to determine what cell collapse looks like and where it occurs. The principle is that what happens to individual particles affects the properties of the final panel on a production line.
It may seem from the titles of some of the papers presented at EPPS 5 that the pure science apparently presented has little influence on reality. However, if you apply the test of ‘is this research relevant to what goes on every day in the panel factory?’ I think you will find that virtually every piece of research presented has a practical value to the panel manufacturer. It is a pity that more people from that industry do not attend the symposia and conferences on offer to them.
Dr Jeremy Tomkinson, leading the team at the BioComposites Centre, made a plea to those manufacturers.
“The attitude of the industry is not sustainable. It cannot go on just cutting prices. We have to get panel products valued by people. But how do we bring new products on stream? Fantoni of Italy has bi-monthly symposia [for designers and technologists] – is this the way forward?
“This conference is for you,” he went on. “Let’s have some feedback. We want to hear from you how you think the industry can improve.”
