| 摘要 |
PURPOSE:To obtain a packaging material excellent in cushioning properties by a method wherein foams in a projected and recessed form are provided on the inner side of packaging material, which is separately mass-produced in advance. CONSTITUTION:Expandable thermoplastic synthetic resin emulsion is applied with brush, roller or the like on the inner side surfaces of a corrugated fiberboard box main body 10. After that, the emulsion is dried in order to remove or reduce the water content in the emulsion. Next, the projected-and-recessed surface side of a mold material 16 is arranged so as to face to the inner side surface of the corrugated fiberboard box main body 10 so as to heat the inner side surface of the corrugated fiberboard box 10 or the inner side, to which expandable thermoplastic synthetic resin 14 is adhered, of the box 10 with heat source having comparatively low temperature such as about 100 deg.C. As a result, the expandable thermoplastic synthetic resin 14 is heated and the resin 14 expands by gas blowing reaction in the inside of the recessed parts 20 of the mold material 16 by about 4-20 times as large as the volume of the resin, resulting in forming cubic and comparatively soft foams 12a with projected cross-section between the inner side surface of the corrugated fiberboard box 10 and the mold material 16. |
