| 摘要 |
1,026,109. Closing plastic bags or tubes. ST. REGIS PAPER CO. May 19, 1964 [June 4, 1963; July 5, 1963], No. 20637/64. Heading B8K. [Also in Division B5] The fused edges 31 (Fig. 5) of walls 11, 12 of a bag made from flexible thermoplastic resinous sheet material are completely covered by closure strip 30 having an elliptical cross - section and made of compatible thermoplastic resin. The closure strip 30 is made by deforming an extruded U-shaped strip as it fuses to the edges 31, (see Division B5). In the configuration described, a sheet of thermoplastic resin is folded to form a gusseted tube 10 (Fig. 2) which is joined at 17 by two strands of molten thermoplastic resin, one of which has a rectangular cross-section and the other a circular crosssection. The tube 10 may be provided with a tubular valve 19 which is made of thinner thermoplastic, and which is sealed to the tube walls by similar strands of molten plastics. Alternatively, a valve may be made by folding in the top part of the gusset 13, and attaching a valve tube to it by strands of molten plastics. One or both ends of the tube may be closed, using a closure strip. Suitable sheet materials are made from combinations of plastics materials whether produced by extrusion coating or emulsion coating or by lamination by means of heat and pressure. |
