| 摘要 |
Plastic bags with a tamper-proof adhesive seal are made by folding and slitting flexible film longitudinally and covering the slit with adhesive coated tape so that one edge of the tape or the folded film will act as a pull tab on a flap covering the bag mouth. Pairs of continuous and of partial transverse welds are applied to the film, the former to seal the edges of individual bags, the latter to provide tear zones to limit the size of the flap when opening the pack for the first time. The bags are prefilled and sealed at their base. Used are continuous mfg. of bags which can be reused and where tearing provides evidence of prior use. The folding, tape application and weld line patterns are suitable for progressive conversion of continuous film into individual sealed bags automatically. |
