| 摘要 |
1421780 Portable containers W C HELLER Jnr 29 Dec 1972 [6 Jan 1972] 60200/72 Headings B8C and B8D [Also in Division B5] A container part is formed from a plastics material 8 which is multi-layered at least in part, one of the layers 4 being provided with particles or droplets of a substance 6 in which heat can be induced by exposure to a high frequency alternating magnetic or electric field so that the part may be joined to another container part. The part containing the substance 6 may be a lid 56 or a body 68. The substance 6 may be carbon, ferrous or ferric oxide, chromium dioxide, vinyl or vinylidene chloride or fluoride. The substance 6 may have a maximum particle size of 250 Á with the range 0À01- 20 Á being preferred. The substance may be present in the range 1-30% by weight of the plastics material of the layer 4. Another layer 2 of the material may be filled with titanium dioxide to hide the colour of the substance. The material may be formed from polyethylene, polypropylene, polystyrene and polyacrylonitrile layers, the layers of the material being of the same or of different polymers. The substance 6 may be present throughout the layer 4 as shown or only as bands at those portions forming the joint with the other container part. Instead of a continuous layer 4, discrete bands (112, Figs. 6, 7) having the substance 6 dispersed throughout may be provided. To maintain a constant wall thickness for the material 8, the wall thickness of the layer 2 may be reduced at the area of the bands (Fig. 9) by adjustment of the die under the control of the device (116). The container may have a lid overlapping the interior Fig. 1 (Figs. 4, 5) or the exterior (Fig. 10) of the body. The container parts may be formed by punching and thermo-forming sheet as shown. The parts may be joined after filling the container. |
