Development of an air-injection press for preventing blowout of particleboard II: improvement of board properties using small-diameter holes for air injection

• Published in: Journal of wood science 2011-12, Vol.57 (6), p.507-511
• Main Authors: Korai, Hideaki, Ling, Nan
• Format: Article
• Language: English
• Subjects: Air injection; Biomedical and Life Sciences; Blowouts; Boards; Bond strength; Bonding strength; Characterization and Evaluation of Materials; Heating; Life Sciences; Materials Science; Moisture content; Original Article; Particle board; Properties (attributes); Water vapor; Wood Science & Technology
• ISSN: 1435-0211; 1611-4663
• DOI: 10.1007/s10086-011-1210-1

An air-injection press, which has holes punched in the heating plates, injects high-pressure air through the holes of one plate into boards during press heating. The air-injection press can manufacture boards from high-moisture-content particles by controlling blowouts of the boards. In this study, boards were manufactured from particles that had a moisture content of 25% by using the air-injection press, which reduced the required pressing time. Boards manufactured by injecting air through holes of 5 mm in diameter were of poor quality with a low internal bond strength of only 0.31 MPa. When the hole diameter was reduced to 1 mm, the internal bond strength increased to 0.44 MPa. A high air-injection pressure of 0.55 MPa also resulted in improved board properties over those for boards manufactured at lower pressures. This was probably because a large amount of binder was released from boards through the 5-mm holes, together with water vapor, during air injection; the small-diameter holes reduced the release of binder, resulting in better board properties.