Untersuchungen zum Kriechverhalten von MDF und Spanplatten im Normalklima

Ohne Zusammenfassung     

MDF—Mitteldichte Faserplatten

MDF boards are being produced in New Zealand too. The author is an expert in this field and gives a survey, of this wood material, its history and the manufacturing process. He compares production costs (table), presents potential uses for which MDF is suitable and gives an optimistic outlook on what he considers a good future for this working material.     

2003年世界中密度纤维板生产能力调查 第2部分

在我们2003年世界中密度纤维板生产能力调查第2部分(北美和欧洲以外地区)中,约翰·瓦德斯沃德先生报道了在2001年底和2002年底之间,北美和欧洲以外地区的生产能力增加了大约12%.与此对照,欧洲生产能力仅增加了3.8％,而北美地区生产能力则减少了1.7%.     

2003年世界中密度纤维板生产能力调查 第1部分

编者按:该调查报告内容截止到2002年底,撰写时间为2003年6月～7月. 《国际木质人造板》2003年中密度纤维板生产能力的调查,证实了我们在2002年调查中关于北美地区生产能力变化较小以及欧洲生产能力扩大的预测.2002年度的调查报告题目为“暂时休整”,该报告认为近两年生产能力的增长超过消费增长的困境将有所缓和,至少在欧洲情况如此.在北美地区,生产能力增长的速度已经放缓.而无论北美地区还是欧洲业内都希望能提高工厂的生产能力利用率及产品价格.     

Optimierung des Eigenschaftsprofils von MDF

During the last years, medium density fibreboards (MDF) became firmly established on the European wood-based material market. The production figures indicate that this tendency is still growing, although in some areas a certain saturation of the market has been reached. MDF manufactured in a dry process offering the possibility of producing such boards in comparable variety and quantity to particleboard, represent a panel product which is a serious competitor for the latter. In Germany, the MDF-production was taken over mainly by particleboard manufacturers. Thus, MDF was no more a competing product but a completion and an enlargement of the existing board range, especially in areas where the particleboard was only suitable for certain purposes. Due to its manufacturing process MDF distinctly differs from particleboard and for this reason reveils a different property profile. The user has not to deal with a substitute product offering “better properties”, therefore, he has to prepare himself for the product. The properties of MDF will be presented in detail and hints for the development of this product will be given.     

Entwicklungsmöglichkeiten von MDF

In Europe MDF production capacities did not expand until the end of the 1970ies, i.e. 10 years later than in the USA. In 1994 MDF had a share of 8% of the German wood-based panel production and merely 6% worldwide in 1993. Internationally, a steady dynamic MDF-production is expected by the year 2000, with an estimated 14% share of the market. Softwood chips, partly with bark, form the main raw material source in German MDF plants. Worldwide, annual plants such as bagasse, bamboo, jute and cotton waste are being used for the manufacture of MDF. Energy used in the milling of 1 ton oven-dry fibre material is about 200 kWh and thus a major cost factor in MDF production. Hence serious attempts are being made in processing to reduce energy consumption through biological or chemical pre-treatment methods. To-day, MDF is being glued with any of the gluing systems used in particleboard production, i.e. urea, urea-melamine and phenolic resins and polymeric diphenylmethane-4,4′-diisocyanate, the most frequently used method being glue application in the blowline. A central problem in MDF-plants is that twice the pressing time of particleboard production is required. The dense and homogeneous fibre structure as well as the variability in density and strength of MDF make it superior in further processing to particleboard and OSB as well as to solid wood. MDF profiles onto whose edges and planes lacquers can be directly applied were one of the first fields of application. Numerous other uses have since been added, e.g. three-dimensional furniture parts, floor-laminates and moulded structural parts. In comparison with other wood-based materials such as particle-board and OSB prospects for MDF for the year 2000 are considered very promising.     

Virtual characterization of MDF fiber network

A virtual design method for medium density fiberboards (MDF) is proposed with the aim to optimize the fiber orientation and lay-up of MDF. The new method estimates the stiffness and strength by using microstructure models of the MDF fiber network. The virtual design is used to improve the manufacturing technology of MDF plates with multilayer oriented fiber structure. Experimental investigations of the mechanical behavior of MDF microstructure for various fiber geometries, glue content and distribution are complicated, time consuming and expensive. On the other side, virtual microstructure design allows to develop a new wood fiber based material with less experimental work. Microstructure models help to better understand the non-linear damage mechanical behavior of a wood fiber network depending on fiber geometrical parameters. Such parameters as crack distribution and fiber deformation on micro-scale level are complicated to experimentally measure, but possible to model using computer simulations. The virtual design tool requires less empirical data. The model takes into account information on average wood fiber orientation, fiber diameter, fiber length and mechanical properties of wood fiber cell wall and glue. The numerical method for strength and stiffness analysis of MDF microstructure was calibrated using standard MDF with non-oriented fibers. It turned out that this method gives precise results for MDF with oriented fibers and even with multilayer structure. The proposed virtual microstructure design tool can significantly improve and speed-up the optimization manufacturing technology of MDF and other wood fiber based composites.     

功能性中纤板开发与研制

介绍我国阻燃、防水、抗静电、防虫、防霉、轻质、高强度等功能性中纤板的开发研制概况,提高产品附加值,拓宽建筑、车辆、船舶、电器、室内外装饰、厨房等应用领域,使我国中纤板培育新的经济增长点,沿着良性轨道发展。     

纤维干燥及其对中纤板质量的影响

从影响纤维干燥质量的几种因素入手,通过分析其内在机理,为中密度纤维板的生产提供一些思路。     

Repeated thermo-hydrolytic disintegration of medium density fibreboards (MDF) for the production of new MDF

European Journal of Wood and Wood Products - Medium density fibreboards (MDF) are currently not recycled after service life, but various publications report on recycling by the disintegration of...     

Fire-retarding properties of nanowollastonite in MDF

Effects of wollastonite nanofibers on fire-retarding properties of medium density fiberboard were studied. Nanowollastonite (NW) was applied at 5, 10, 15, and 20 g/kg dry weight basis of wood fibers and compared with reference specimens. Two application methods of NW were used: surface application (SA), and internal application. Density was kept constant at 670 kg/m³ for all treatments. Specimens of 150 × 130 × 9 mm³ were prepared and fire-retarding properties were measured using two devices: slide fire test device and fixed fire test device. The properties included: weight loss, ignition and glowing times, width and length of the burnt area, and fire endurance. The obtained results indicated that most fire-retarding properties were significantly improved with the increase in NW-content up-to 15 %, including weight loss, ignition and glowing times, and fire endurance. Higher amounts resulted in decreasing of the properties which was partly due to the less fiber-content, and partly due to the absorption of resin by the wollastonite nanofibers. It can be concluded that SA of NW is more effective in improving fire-retarding properties of medium density fiberboard. Furthermore, 10 % of NW is recommended as an optimum level of consumption.     

中密度纤维板静电粉末喷涂工艺条件研究

采用正交试验方法,分析得出了中密度纤维板静电粉末喷涂最佳工艺参数：喷涂距离150 mm,供粉气压0.05 MPa,静电电压60 kV,此时一次上粉率在30%以上。提出了提高一次上粉率的工艺方法,即在设备性能允许情况下,尽可能缩短喷涂距离,适当提高静电电压。     

Mechanisch-technologische Eigenschaften von MDF aus Pappelholz

Ohne Zusammenfassung     

功能性中纤板开发与研制

介绍我国阻燃、防水、抗静电、防虫、防霉、轻质、高强度等功能性中纤板的开发研制概况 ,提高产品附加值 ,拓宽建筑、车辆、船舶、电器、室内外装饰、厨房等应用领域 ,使我国中纤板培育新的经济增长点 ,沿着良性轨道发展。     

意杨轻质中密度纤维板的研制

重点探讨了生产意杨轻质中密度纤维板时树种、纤维形态、纤维分离、施胶、热压等工艺因素对板材性能的影响,并对其成本及其经济效益进行了分析.结果表明开发意杨轻质中密度纤维板在技术上是可行的,而且具有显著的经济效益.     

MDF生产线热能系统的发展

在收集国内外MDF生产线新型热能系统技术信息的基础上,结合能源开发与节约技术的发展,介绍生产线建立能源系统的新模式以及环保方面的处理。