VOLUME 60, ISSUE 4/2019

The approach of the project was the development of a process technology for the production of paper, board and cardboard in the dry process on the basis of MDF technology. The advantages are savings in water, energy and process chemicals as well as significantly lower depreciation costs for the plant technology. The disadvantages, on the other hand, are the high and indispensable use of binding agents, significantly lower machine speeds and MDF properties that are unsuitable for packaging applications. Within the scope of the project, the feasibility of producing ultra-thin MDF using a combination of MDF process technology and airlaid technology was demonstrated. In comparison to corrugated base paper, higher stiffness and layer strengths were achievable, but lower tensile and burst strengths. The very high scatters in the property values of the ultra-thin MDF are an existing challenge and presumably due to the inhomogeneity of the dry laid nonwovens. The ultra-thin MDF showed a very good formability to sinusoidal wave structures and for selected binders the recyclability in the paper recycling cycle was given.

In this work, the glowing combustion of renewable resource insulation materials is characterized. It contains tests at cone calorimeter and at a testing facility for measuring weight loss at glowing combustion, an invention of Fraunhofer WKI. First of all, the tested products show a disposition to smoulder continuously. Regardless of the production method, high-density wood fibre insulation boards indicate a linear relationship between the bulk density and the so-called glowing combustion acceleration. The differences in bulk density also result in a variation of maximum heat release rate while glowing combustion. Then again, it should be noted that all different loose materials with nearly the same bulk density lead to a similar glowing combustion acceleration. The usage of flame retardant reduces the propagation of glow, but will not stop it. The release of gaseous fire products is examined with a Fourier-transform infrared spectroscopy, a lead compound is carbon monoxide.

Investigations were carried out on the continuous ultrasonic impregnation of fleece-laminated roll veneers by using a radiation curing acrylate. The influence of different process parameters on the impregnating agent absorption was analysed. The amplitude as well as the immersion bath volume could be determined as relevant influencing factors for a stable course of the process. Irrespective of the type of wood (pine, beech, oak) an improvement in impregnating agent absorption could be recorded by an ultrasonic treatment. The resulting process temperatures were constant over time due to the improved parameters. Thus an effective and continuous ultrasonic impregnation with recurring transient cavitation could be developed.

During the last 15 years, enormous efforts have been made in developing models for predicting the service life of wooden structures and components. Currently, a framework of how exposure, dimension, design details and the material-intrinsic ability to take up and release water can be linked to model the moisture risk in wood products is in principle available. The aim of this study was to compare the “predictive power” of such a service life prediction model with that of different groups of wood users. Besides professional wood-related craftsmen, architects, wood scientists and customers of so-called “DIY-markets” were asked to estimate the time span between the beginning of exposure and the occurrence of fungal decay on case examples with known history and service life. A set of models predicted the service lives of the different example cases fairly well with the exception of one playground structure, which was made from preservative treated wood. Material specific data on the resistance and wetting ability are needed to further improve the model fit. In many cases, the average service life estimates of all survey respondents met the real service life fairly well, but suffered partly from high scattering. Groups of experts such as wood-related craftsmen and wood scientists did not provide significantly better estimates than non-experts. The need for comprehensive and elaborate prediction instruments became evident, since neither “laymen” nor “experts” were able to provide sufficient statistically reliable estimates for service lives of wooden components. The predictive power of any expert is dependent on personal experience, which is often restricted to local climatic conditions and regional construction techniques and traditions.

In addition to the fundamental normative, legal and other framework conditions for the use of cooker hoods, their technical evaluation was a central element of this study. Representative wall mounted hoods, chimney cooker hoods and downdraft hoods were subject to the investigation. It was focused on the evaluation of the odour reduction considering the mounting conditions, ventilation-/circulation-mode, regulated domestic ventilation and filter aging. The evaluation of the vapour collection was performed with an optical method. The study was completed with investigations of homeliness and air quality as well as the system-dependent costs and the economy regarding energy efficient buildings. The results of the project were summarized in a guideline for users, designers and experts.

The application quantities of glues determine the quality of the component in coating processes. They should be measured as continuously as possible and at a high feed rate. These requirements can be addressed by means of the terahertz measuring method. Material and technical parameters are examined. The suitability of the process for the furniture industry is demonstrated.

Terrace and balcony decking is an important application for solid wood. In this installation situation (use class 3.2 acc. to DIN 68800-1, 2011, and EN 335, 2013, resp.), wood is generally exposed to an attack by wood-decay fungi. However, in practice often problems with wood-disfiguring microorganisms, like blue stain, mould, or aeroterrestrial algae occur. Within a research project was investigated, whether biocide-free silicone based coatings can prevent this better than common terrace oils. Different test products from water-based and solvent-based silicone resins and oils were tested. In result, the silicone-based coatings were not able to prevent the infestation by wood disfiguring microorganisms, despite of their clear hydrophobic effects. Nevertheless, silicone-based coatings appeared to be suitable for surface treatment of solid wood decking, but appropriate formulations (recipes) must be developed and optimised.

In 13 parts were presented the main high educational centers for wood science and technology of 33 European countries. Part 14 to 21 presented an introduction regarding the North American forest and wood industry as well the Canadian and USA institutions for wood science and research. Part 22 to 28 started an overview in Asia (Japan, Thailand, Iran and Vietnam) and this paper is continuing with aspects of the forestry in Mongolia.