Advertisement

Contact thermal post-treatment of oriented strandboard to improve dimensional stability: A preliminary study

  • Cláudio Henrique Soares Del MenezziEmail author
  • Ivan Tomaselli
ORIGINALARBEITEN ORIGINALS

Abstract

The oriented strandboard (OSB) has less dimensional stability than plywood, but they are competitive panels and have been used for similar ends. The wood-water relation variables, such as thickness swelling and water absorption, express this OSB dimensional instability and can be explained by two main factors: wood hygroscopicity and imposed hot-pressing stresses. The objective of this present paper was to propose a thermal post-treatment as a method to improve OSB dimensional stability by decreasing wood hygroscopicity and releasing hot-pressing stress. OSB panels from Pinus taedawood were produced in laboratory, and their characteristics were: single layer, 0.8 g/cm3; 8% phenolic resin and without wax. The OSB panels were treated in a laboratory press at 250 °C for about 4, 7 and 10 minutes. The wood-water relation variables, thickness swelling (TS), water absorption (WA), equilibrium moisture content (EMC) and springback or permanent thickness swelling (PTS) were determined and compared with untreated panels. The results showed that the proposed thermal treatment was effective to reduce TS, EMC and PTS, but didn’t affect WA which was affected by panel density reduction. The longer the treatment the higher the dimensional stability, and panel weight loss could be used as predictive variable for the efficiency of the treatment.

Keywords

Thermal Treatment Dimensional Stability Equilibrium Moisture Content High Performance Liquid Chro Oriented Strand Board 
These keywords were added by machine and not by the authors. This process is experimental and the keywords may be updated as the learning algorithm improves.

Kontaktwärme-Nachbehandlung von OSB zur Verbesserung der Dimensionsstabilität: Voruntersuchung

Zusammenfassung

OSB hat zwar eine geringere Dimensionsstabilität als Sperrholz, aber dennoch ist es für viele Verwendungen ein wettbewerbsfähiges Produkt. Parameter wie Dickenquellung und Wasseraufnahme verdeutlichen die Dimensionsstabilität von OSB. Diese lässt sich durch zwei Hauptfaktoren erklären: zum einen durch die Hygroskopizität von Holz und zum anderen durch die beim Heisspressen eingebrachten Spannungen. Ziel dieser Veröffentlichung ist es, eine Wärmenachbehandlung als ein Verfahren zur Verbesserung der Dimensionsstabilität von OSB vorzuschlagen, welche die Hygroskopizität des Holzes verringert und die Spannungen durch das Heisspressen abbaut. Labor-OSB-Platten aus Pinus taeda Holz wurden mit folgenden Eigenschaften hergestellt: einschichtig, 0,8 g/cm3; 8% Phenolharz, kein Wachs. Diese Platten wurden in einer Laborpresse bei 250 °C für ungefähr 4, 7 und 10 Minuten behandelt. Die Parameter Dickenquellung (TS), Wasseraufnahme (WA), Gleichgewichtsfeuchte (EMC) sowie reversible und irreversible Dickenquellung (PTS) wurden bestimmt und mit den Werten von unbehandelten Platten verglichen. Die Ergebnisse zeigten, dass mit der Wärmebehandlung zwar die Parameter TS, EMC und PTS verringert werden konnten, WA jedoch davon nicht beeinflusst wurde. Diese wird durch die abnehmende Rohdichte der Platte beeinflusst. Mit zunehmender Dauer der Wärmebehandlung verbesserte sich die Dimensionsstabilität. Der Masseverlust der Platten ist ein gutes Mass für die Wirksamkeit der Behandlung.

References

  1. 1.
    Avramidis S, Smith LA (1989) The effect of resin content and face-to-core ratio on some properties of oriented strand board. Holzforschung 43(2):131–133CrossRefGoogle Scholar
  2. 2.
    Bourgois J, Bartholin MC, Guyonnet R (1989) Thermal treatment of wood: analysis of the obtained product. Wood Sci Tech 23(3):303–310CrossRefGoogle Scholar
  3. 3.
    Bourgois J, Guyonnet R (1988) Characterization and analysis of torrified wood. Wood Sci Tech 22(2):143–155CrossRefGoogle Scholar
  4. 4.
    Del Menezzi CHS (2004) Dimensional stabilisation by heat treatment and their effects on the oriented strandboard properties. PhD Dissertation on Forest Products Technology and Utilization. UFPR, Curitiba, p 226 (in Portuguese)Google Scholar
  5. 5.
    Hashim R, How LS, Othman S, Yamamoto K (2001) Effect of extractive removal on dimensional stability and bonding properties of particleboard made from hybrid of Acacia. J I Wood Sci 15(5):261–266Google Scholar
  6. 6.
    Hsu WE, Schwald W, Shields JA (1989) Chemical and physical changes required for producing dimensionally stable wood-based composites. Part 2: Chemical and physical changes required for producing dimensionally stable wood-based composites. Wood Sci Tech 23(3):281–288CrossRefGoogle Scholar
  7. 7.
    Irle M, Adcock T, Sekino N (1998) The theological behavior and dimensional stability of steam pre-treated particles. In: European Panel Products Symposium, Proceedings, 2, BioComposites Centre, Llandudno, pp 24–29Google Scholar
  8. 8.
    Kelly MW (1977) Critical literature review of relationships between processing parameters and physical properties of particleboard. General Technical Report FPL-10, USDA, Washington, p 65Google Scholar
  9. 9.
    Lu X, Pizzi A (1998) Curing conditions effects on the characteristics of thermosetting adhesives-bonded wood joints–Part 2: Hot postcuring improvement of UF particleboard and its temperature forecasting model. Holz Roh- Werkst 56(6):393–401CrossRefGoogle Scholar
  10. 10.
    Militz H (2002) Thermal treatment of wood: European processes and their background. In: Annual Meeting International Research Group on Wood Preservation, Proceedings, 33, Cardiff, p 10Google Scholar
  11. 11.
    Ohlmeyer M, Kruse K (1999) Hot stacking and its effects on panel properties. In: European Panel Products Symposium, Proceedings, 3, Cardiff, pp 293–300Google Scholar
  12. 12.
    Pincelli ALPSM (1999) Effects of the thermal rectification on the finishing quality, bonding and color of the wood from Eucalyptus saligna e Pinus caribaea var. hondurensis. MSc Thesis on Wood Science and Technology, Piracicaba: USP/ESALQ, p 115 (in Protuguese)Google Scholar
  13. 13.
    Rowell RM, Youngs RL (1981) Dimensional stabilization of wood in use. Research Note, FPL-0243, USDA, Washington, p 8Google Scholar
  14. 14.
    Sekino N, Inoue M, Irle M, Adock T (1999) The mechanism behind the improved dimensional stability of particleboards made from steam-pretreated particles. Holzforschung 53(4):435–440CrossRefGoogle Scholar
  15. 15.
    Stamm AJ (1964) Wood and cellulose science. Ronald Press, New York, p 549Google Scholar
  16. 16.
    Suchsland O, Xu H (1991) Model analysis of flakeboard variables. For Prod J 41(11/12):55–61Google Scholar
  17. 17.
    Tjeerdsma BF, Boonstra M, Pizzi A, Tekely P, Militiz H (1998) Characterisation of thermally modified wood: molecular reasons for wood performance improvement. Holz Roh- Werkst 56(3):149–153CrossRefGoogle Scholar
  18. 18.
    Welbacher CR, Rapp AO (2002) Comparison of thermally modified wood originating from four industrial scale processes-durability. In: Annual Meeting International Research Group on Wood Preservation, 33, Proceedings, Cardiff, p 13Google Scholar
  19. 19.
    Winistorfer PM, McFarland DL, Slover RC (1992) Evaluating the performance of ten wax formulation and three application rates on properties of oriented strandboard. In: International Particleboard/Composite Symposium, 26, Proceedings, Pullman, pp 236–250Google Scholar

Copyright information

© Springer-Verlag 2005

Authors and Affiliations

  • Cláudio Henrique Soares Del Menezzi
    • 1
    Email author
  • Ivan Tomaselli
    • 2
  1. 1.Forest Engineering Department, Faculty of TechnologyUniversity of BrasiliaBrasíliaBrazil
  2. 2.Forest and Wood Science Centre Federal University of Paraná – UFPRCuritibaBrazil

Personalised recommendations