Water vapor pretreatment shavings improve particle size stability

The opportunity of steam pretreatment shavings to increase the dimensional stability of particleboard is studied from the potential thickness recovery of wood shavings with increased density and the breaking of the adhesive bond web in the particle board. Since the latter depends on the balance between the strength and the stress imposed on the bond, the effect of steam temperature (160-220 ° C) on bond quality, recovery stress on compressed wood, and plane swell stress is investigated. It was found that steam pretreatment: 1) reduced the thickness recovery of wood shavings with increased density, which is particularly effective when the steam temperature is raised above 190 °C; 2) when the steam temperature is lower than 210 ° C or using a relatively high pressure The machine pressure is 1.5MPa, the bond strength does not cause a practical reduction; 3) the recovery stress of the compressed wood is reduced, which is mainly caused by the improvement of the compressibility of the wood; 4) the flatness of the shavings is reduced. Stress, which is related to the decrease in hygroscopicity and elasticity.

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