| 摘要 |
1,163,437. Seaming non-metallic sheet material. W. BAHLSEN. 23 Sept., 1966 [15 Oct., 1965], No. 42468/66. Heading B5K. Surfaces are bonded together by applying a melt adhesive to at least one of the surfaces, conducting additional heat to the bonding position during the application of the melt adhesive, and then bringing the surfaces into contact. By melt adhesive is meant an adhesive material comprising a plastics material and a wax component. The plastics material may be a polyvinyl resin, such as polyvinylacetate, polyvinylisobutylether or an acid vinyl ester, or polyethylene or polypropylene. The wax component may be a paraffin, a natural wax such as carnuba wax, a synthetic resin or a derivative of a natural resin such as colophonium or fusible polyamides. In one embodiment, Fig. 1 (not shown), the knife edge of a chisel-shaped tool is provided with a layer of melt adhesive by dipping the tool into a reservoir of the adhesive. The tool is heated by internal electrical heating elements or by passing heating media therethrough. The tool is introduced into the mouth of a filled bag so that the adhesive layer contacts the walls of the bag mouth and on removal of the tool this layer remains stuck to the walls to form a seal. In a further embodiment, Fig. 2, the adhesive is applied by a tool 4 provided with slits 5, 6 which, after the tool has been dipped in the melt adhesive, retain adhesive therein by capillary attraction until the tool contacts one or both surfaces to be bonded and the adhesive is released. Instead of the slits 5, 6, tubes, grooves or other indentations may be formed in the tool 4 to produce the capillary effect. The tool 4 is used to seal a flap 8 to an underlying flap 9 of a folding box 7. The tool 4 is heated either electrically or by circulation of a fluid therethrough. In a modification, the adhesive is fed through the inside of the tool 4, e.g. through a passage in a support 10 and through tubes 11, 12 into the slits 5, 6. In another embodiment, Fig. 3, a tool 13, formed similarly to the tool 4, is moved continuously in the direction of the arrow 14 over a layer 15. Slight pressure is applied at 17 to a second layer 16 to continuously bond the layers together. In a still further embodiment, Fig. 6 (not shown), the melt adhesive is applied to a reciprocating chisel-shaped heated tool by contact of the tool with a roller rotating in a bath of the adhesive. In yet another embodiment, Fig. 7, the tool is in the form of a wheel 32 continuously rotating in a melt adhesive bath 33 and bonds a flap 36 on a lid 34 to a box body 35. The wheel 32 may be heated by a heated hub 37. |
