| 摘要 |
In a plastic sheeting material incorporating an array of bubble cells (12), the cells are shaped with two chambers (31, 32) connected by a constricted region (34). The chambers (31, 32) are part-spherical e.g. in the form of truncated spheres. The constricted region has concave side walls (37, 38) and/or a concave top wall (36). The sheeting may have two, three or more layers. Moulds (100, 200) for producing the sheeting material have suitably-placed suction holes (104, 204). |
