Abstract: The invention is primarily concerned with a sandwich material (55) made of sheets based on paper. This material is substantially comprised of a sheet (42) of corrugated paper (44) forming one or several layers. An intermediate paper sheet (31) is bonded to the corrugations of the sheet 42. A film (29) of a thermoplastic compound adheres physically as the result of an extrusion to the outer side of the intermediate paper sheet (31).The process for manufacturing this material consists firstly in extruding a film (29) of thermoplastic compound on the intermediate paper sheet (31), and then in bonding the web (27) of protective layer thus obtained on the corrugations of the sheet of corrugated paper (42).The invention is remarkable in that these operations are carried out on a standard machine for manufacturing corrugated paperboard.

Abstract: A knockdown seat comprises a base member, a seat member and optionally a back member, the seat and back members being supported on the base member. The members are formed of foldable semi-rigid sheet material, such as cardboard, plastics material or sheet metal. In one embodiment the seat is a chair and the seat member and back member each comprise a single sheet folded into a triangular prism and the base member includes two side supports each comprising one sheet folded spirally. Slots in the edges of the sheets of the seat member and the back member double joint them in complementary slots in the upper edges of the side supports. In another embodiment the seat is a stool. The base member comprises one or two sheets having panels forming the support structure of the base member and flaps adapted to bear on the panels forming the seat member. Slots in the flaps and the upper edges of the panels define joints interlocking the seat structure.