Possibility of production of binderless boards using wood powder by rolling

摘要

Recently, it has become more and more important to minimize environmental pollution. As an attempt to alleviate the environmental problems in materials, new wood based materials without using any adhesives and binders have been investigated. From this point of view, wood powder can be useful because it can be solidified and bonded under optimum pressure and temperature. This is because the component of wood, especially lignin and hemicelluloses, becomes soft and fills among components during heating and compacting. In addition, the powder form causes effective bonding of each particle. From the viewpoint of powder forming, Near Net Shape forming actually can be performed using plastics and metal powder. Therefore, the development of this technology enables the production of binderless wood products with arbitrary shapes and this leads to effective use of waste woods such as construction scraps. In this study, as fundamental tests for rolling, hot-pressings of wood powder of cedar were carried out at various forming conditions, temperature and compaction speed in order to confirm the possibility of solidification without using petroleum adhesive, and also to produce useable binderless board. Effects of the forming conditions on the mechanical properties, bending strength and bulk density of the hot pressed board are discussed. The experimental results show that the mechanical properties increase with increasing temperature during the hot press, and then, the maximum bending strength is about 30MPa. However, when the temperature is too high, the mechanical properties tend to decrease due to burning. Finally, general rolling was conducted based on hot press results to produce boards continuously. However, it was necessary to push the powder between rolls in order to obtain a sound board.