| 摘要 |
PURPOSE:To obtain strength equal to that of the corrugated fiberboard with corrugating core medium by a method wherein polyurethane foaming resin stock liquid is poured between linerboards on conveyer type press belts which is provided with leakproof dams against the leak of liquid through the sides of two sheets of the linerboards, foamed while being pasted to the linerboards and finally hardened. CONSTITUTION:Expandable urethane stock mixed liquid, which is mixed by a polyurethane foaming stock mixer 3, is fed by spraying, applying, scattering or pouring in liquid form onto the one linerboard 1 out of two linerboards, which are fed at constant speed for manufacturing fiberboard. While the stock liquid under expanding is prevented from leaking by leakproof dams 5 of liquid through the sides of the linerboards, the other linerboard 2 is pasted onto the stock liquid. The resultant stock liquid is pinched with warming conveyor type press belts 4 so as to be hardened and aged under heat in order to form a fiberboard sheet. The sheet is cut with a cutter 7 and creased in order to obtain a heat resistant fiberboard sheet 6 as product. |
