| 摘要 |
A sheet piece intended to form, for example, an encasing wall (53) of a portable container, consisting of a plurality of material layers (54, 55, 56) mainly of paper. The material layers are provided with a large number of localized impressions distributed uniformly over the surface of the layers with spaces in between the impressions. The impressions extend from the principle plane (58, 59, 60) of each layer. The impressions (57, 62) in adjacent layers are, with respect to their positions, displaced relative to one another as viewed in the normal direction of their principle planes (58, 59, 60). This involves that the impressions in one layer are located directly in front of the spaces in adjacent layers. Each of the layers is joined with its adjacent layers by means of an adhesive, whereby a large number of closed cells (64) are created, so that at most two layers are directly joined together with each other. |
