| 摘要 |
Flexible packages having an openable and resealable interlocking closure made from a continuous web of flexible film, the closure being formed transversely to the direction of film flow at the consumer preferred position across one end of the package during package formation at line speed. The system utilizes a converter device mounted atop or adjacent to standard packaging apparatus to form a small amount of the running packaging film into the resealable closure structure as an integral part of the film extending transversely to the long dimension of the package. The converter functions with both horizontal and vertical form/fill/seal wrapping machines and with overwrap packagers, and uses diverse packaging films such as polypropylene, polyester, polyvinyl chloride, high and medium density polyethylene and various film laminations. The package formation begins by feeding the plastic packaging film into the converter where the film is first automatically fanfolded across the entire width of the film to form a stack, the layers of which are immediately heat sealed together forming a multilayered semi-rigid strip of typically one half inch width extending completely across the film width in plane with the film. The number of folds in the stack varies depending on the thermoforming properties and thickness of the particular film being used. In one embodiment of the invention, the resealable locking feature is next thermoformed into the multilayered strip which then continues through the packaging machinery in the usual manner, encircling the product and passing through the end sealer where the package ends are sealed and cut, and the front and back film panels are pressed together closing the resealable locking feature. In another embodiment of the invention the multilayered semi-rigid strip carried by the packaging film is abraded on one surface to remove the thermoplastic coating and leave that surface of the strip uncoated, the film being then passed into the package forming apparatus where the product wrapping takes place. After emerging from the package forming apparatus the package ends are sealed and the package resealable locking feature is completed.
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