| 摘要 |
<p>PURPOSE:To obtain a structural material excellent in water resistance and strength by pressing a laminated material formed by arranging thin papers between both cardboards and holding polyethylene sheets between the cardboards and the thin papers under heating to integrally bond the cardboards and the thin papers through the molten polyethylene sheets. CONSTITUTION:In a structural material suitably used in a drum taking up a cable or wire or a palette for a lift track, cardboards 1 are arranged outside a large number of laminated thin papers 2 and polyethylene sheets S are held between the cardboards 1 and the thin papers 2. The surfaces of the cardboards 1 are pressed under heating by a flat mold for a predetermined time to integrally bond the cardboards 1 and the thin papers 2 through the molten polyethylene sheets S and, after pressure is released, the whole is allowed to stand to naturally cool to complete the structural material. By this method, the structural material having sufficient water resistance, strength and processability can be inexpensively obtained even from inferior paper issued from a papermaking maker.</p> |
