History of Wood-Based Composites

The range of wood-based composite panels available in the market is a result of the continuing development of processing techniques and adhesive technologies (Table 12.3). Wood glues have been used for centuries, but availability in quantity with consistency of performance was achieved only when synthetic formaldehyde-based adhesives became available. 

It was not until after World War II that particleboard appeared as the first product to use urea formaldehyde (UF) as an adhesive. Particleboard provided a low cost way of converting low grade raw materials into a useful product. Capacity increased rapidly after the World War II to meet the huge demand for building materials, especially in Europe and the technology quickly spread to other countries Experience with this product showed the benefits of controlling the particle size and geometry and lead to improved performance. 

Early fibreboards were developed by taking fibre from a wet-process fibre line, drying this, mixing it with resin, and pressing it as had been done for particleboard. However, in the last three decades medium density fibreboard (MDF), a UF bonded and dry formed panel, has largely replaced the early fibreboard products. 

Oriented strand board (OSB) was developed as an alternative to plywood and is now used in large volumes in construction, particularly in North America. It uses small thin flakes or strands which are oriented to provide directional properties. 

These are prepared with specialist flaking equipment that can use small diameter logs. Initially this was from species having no other use, but as capacity has grown alternative wood sources have been used. The process evolved from the waferboard manufacture that used thin flakes or wafers to form a panel where the wafers performed as small veneers. The increased slenderness ratios of strands resulted in improvements in both strength and directional properties so that OSB became an alternative to plywood. The reduced width of the strands compared with wafers allowed them to be produced from smaller diameter wood. 

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