Raw Material for Future MDF Production
Global consumption of wood-based panels is growing and new investments are being made to meet these needs. However, with the increasing demand for medium density fiberboard (MDF) and competition from the biomass energy industry, more and more attention has been paid to the future availability of wood.
In the past 20 years, the BioComposites Center has studied the application of various biomass materials in the production of MDF. Business and environmental issues are driving this work. Business drivers include ensuring that new materials ease the decline in timber supply and diversify the market. Environmental issues, such as the need to make better use of by-products/wastes from other industries and the need to increase recycling, are also important factors.
In the early 1990s, the center conducted a comprehensive study to determine the applicability of selected agricultural raw materials (ARMs) for MDF production. The selected crop raw materials (ARMs) were wheat straw, flaxseed straw, awn grass, yellow poplar and hemp.
Some of the main objectives of this study are to determine the optimal level of agricultural raw materials (ARM) and resin content in order to optimize the quality of MDF. The study also examined the feasibility of establishing supply chains between agricultural communities and the wood-based panel industry. Medium density fiberboard (MDF) fibers are produced from agricultural raw materials (ARM) and then mixed with wood fibers and urea formaldehyde (UF) resins using a pilot scale thermal mill. The wood substitution for products of low to medium level (20% and 40%) was tested. The results show that all the materials are suitable, the wood substitution level is as high as 20%, and there is no significant loss in quality. For some materials, when the wood substitution level is 40%, the performance of the board is reduced to a certain extent. Only poplar or awn grass can be used as the whole wood substitution. It is also possible to grind wheat straw separately, but even with high content of urea formaldehyde (UF) resin and catalyst, it is unsuccessful to try to produce the straw board bonded with urea formaldehyde (UF) resin. The fact that sheets can only be manufactured with isocyanate (MDI) resins is a key problem of straw. This is due to the presence of wax on the surface of straw, which significantly reduces the bonding ability of urea formaldehyde (UF) resin.
The project also studied one-year storage of materials, including protected and unprotected materials. The results show that this does not seem to have a significant impact on the properties of the sheet, so it is possible to store a large amount of harvested crop raw materials (ARM).
Feedback from the industry suggests that more promising crop raw materials (ARMs) may be considered alternatives. However, it is obvious that it will only be considered if it can be supplied at the same or lower cost as wood and is guaranteed in terms of supply safety and quality. The industry also wants more information about the long-term impact of the production process itself, as higher levels of silicon dioxide and extractives can lead to equipment wear and tear.
At present, the center’s research on raw materials for MDF production focuses on the use of regenerated MDF. A large amount of discarded MDF can be obtained from the sources after consumption and before consumption. This is a potentially valuable source of fibers that has not yet been used. In the past, many technologies have considered this problem, but based on batch production process, it needs high pressure and energy consumption, which is unaffordable. However, the recent development of MDF Recovery Ltd. and the comprehensive development of some of Europe’s largest plate manufacturers have proved to be feasible and cost-effective. It can be used in combination with store decoration of recycled products, market pull of retail industry and regulatory agencies to promote circular economy of manufacturing industry.