| 摘要 |
A foamed plastic material of polyethylene or polystyrene capable of being heat-shaped for use in making packing containers wherein by stretching of the foam the cells therein are given a lenticular or elongated structure. In the case of a lenticular cell structure, produced by a bi-axial stretching operation, the individual cells are situated in layers in parallel planes. In the case of an elongated cell structure, produced by a mono-axial stretching operation, the individual cells are situated with their longitudinal axes in parallel planes. |
