Abstract
A strand-particle board (SPB) was manufactured using unoriented strands for the surface layers and unoriented particles for the core layer. Todomatsu (Abies sachalinensis) strands, recycled waste wood particles, and emulsifiable methylene diphenyl diisocyanate (EMDI) as a resin adhesive were used. The effect of resin content (3 and 6%), surface moisture content (5, 10, 15 and 20%) and press temperature (170, 200 and 230°C) on physical properties, and the effect of resin content (10%), surface moisture content (20%) and press temperature (170, 200 and 230°C) on blisters were investigated using laboratory boards. The results are summarized as follows :
1)A suitable manufacturing condition for the EMDI bonded SPB was found to be a press temperature of 230°C, a resin content of 6%, and a surface moisture content of 15%. This condition produced the most superior properties, namely a board density of 0.62 g/cm3, an internal bond of 0.93 MPa, a modulus of rupture of 43.1 MPa and a thickness swelling of 1.9%.
2)There were blisters in surface strand layers of all manufactured boards when surface moisture content was 20%.
3)It was supposed that the carbon dioxide generated by the reaction of EMDI and water influences blisters and physical properties.
