Wood fiber

from Wikipedia, the free encyclopedia

Wood fibers are elongated, axially arranged wood cells that serve to strengthen the wood . The fiber content in most hardwoods is between 50 and 60%; here one speaks of libriform fibers . In the case of conifers , it is the longitudinal tracheids that make up 90–95% of the entire softwood body. Also annual plants form of woody fibers, however, the fiber content is significantly lower than with wood. Fibers for paper production are called wood pulp or cellulose .

properties

Wood fibers are characterized by their arrangement, shape, wall thickness and thickening as well as their length. The softwood fibers are longer than the hardwood fibers, typical values ​​are 3.5–6 mm for spruce, pine or fir fibers and 1–1.5 mm for poplar, birch or beech fibers. The degree of slenderness (ratio of length to thickness) is around 100 for softwoods, below that for hardwoods, for example 38–60 for beech.

Manufacturing

Wood fibers are mostly obtained from debarked wood chips (possibly by adding waste chips). Subsequent steaming, boiling and chemical or mechanical digestion are used to obtain individual fibers, fiber bundles and fiber fragments. In practice, the defibrator process with different defibrating units ( refiners ) is usually used to defiber the wood . This is a single-disc process in which the preheated wood chips are crushed between a fixed and a rotating grinding disc.

use

Wood fiber insulation

Wood fibers are primarily used for the production of wood fiber materials. Hard fiberboard is used in vehicle construction and the furniture industry. In the construction industry they are used for concrete cladding, in prefabricated house construction and in interior work, for example. B. used for floor slabs. Medium-density fibreboard is used as furniture and kitchen fronts, in shops and in loudspeaker construction. Low density fibreboards are used in particular as wood fiber insulation boards .

Economical meaning

Fibreboard represents a large market for wood fibers . Germany is the leading location for the wood-based panel industry and medium-density fiberboard in particular has been one of the fastest growing wood-based products in recent years. After a strong increase in production in the years 2002-2005, however, production in 2008 fell by 9.3% compared to the previous year: to 3.9 million m³. Among the natural insulation materials that are installed in Germany every year, wood fiber insulation materials take first place with a market share of 60%. In addition, wood fibers are processed into so-called non-wovens (non-woven textiles). Around 27,000 t of this is processed into fleeces and felts for the automotive industry .

supporting documents

  1. ^ Association of the German Wood-Based Panels Industry (VHI). Industry data 2008
  2. ↑ News portal Renewable Raw Materials Association of Wood Fiber Dämmstoffe e. V. (VHD) dated December 2, 2008
  3. ↑ Michael Carus, Jörg Müssig, Christian Gahle: Natural fiber reinforced plastics. Edited by the specialist agency for renewable raw materials e. V., Gülzow 2008 Download (PDF; 1.3 MB)

literature

  • Peter Niemz, André Wagenführ: Materials made of wood. In: André Wagenführ, Frieder Scholz: Taschenbuch der Holztechnik. Specialized book publisher at Carl Hanser Verlag, Leipzig 2008; Pp. 127-259. ISBN 978-3-446-22852-8 .
  • Manfred Dunky, Peter Niemz: Wood-based materials and glues. Springer Verlag, Heidelberg 2002. ISBN 3-540-42980-8 .

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