| 摘要 |
PURPOSE:To make weight small and to uniform strength of the facial direction by diffusively arranging aggregate between the base plates made of wood and bonding it to the base plates and also packing and forming a rigid urethane foam layer in the void space which is defined by the base plates and aggregate. CONSTITUTION:Waterproof layers 3 are provided to the faces 2A of each side in a set of base plates 2. For example the waterproof layers are formed by sticking the waterproof sheets wherein cellulose paper is impregnated with synthetic resin having water resistance to the respective base plates 2 by an adhesive. Both base plates 2 are oppositely arranged so that both waterproof layers 3 are faced. Proper number of aggregates 4 are bonded to the waterproof layers 3 and zigzag diffused and arranged between both base plates 2. For example, this aggregate 4 is formed of the chips of wood having a disk shape. The both end faces 4A thereof are bonded to the waterproof layers 3 by the adhesive 7. Rigid urethane foam layers 5 are bonded to both of the waterproof layers 3 and aggregate 4 and provided in the void spaces 8 which are defined by the waterproof layers 3 and aggregate 4. As this method, a mold is fitted to the circumferential edge parts of the base plates 2 and urethane resin is introduced into the void spaces 8 and may be foamed and cured. |
