Method of producing multi-layered and shaped wall covering material of corrugated cardboard
 A method of producing a shaped wall covering material composed of a corrugated cardboard substrate, a porous buffer layer adhered onto one side of the substrate and a thermoplastic resin liner coated on the outer surface of the buffer layer. The starting materials are set in a hot-press in an orderly piled arrangement with interposed adhesive materials and subjected to press-shaping between male and female dies with application of heat. During the shaping operation, air is sucked from the gap between the substrate and the shaped surface of one die through holes intentionally formed in this die. The resultant attraction of the piled materials to this die facilitates the shaping and prevents a layer-separation or deformation of the product attributable to a sticking tendency of the liner to the other die. The suction can be enhanced by forming pin-like protuberances on the die surface contacting the substrate to intrude into the buffer layer and squeezing the buffer layer and/or substrate in a marginal region by a periopheral wall-like protuberance formed, for example, on the other die surface. 
Nissan Motor Company, Ltd.
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Toshihiko
Fujii