Closure for film packages and method of making same

Claim 1

A package including a tubular envelope comprising synthetic resinous thermoplastic material, the envelope being in generally intimate surrounding association about a product contained therewithin, the opposite ends of said envelope being gathered tightly about said product and extended outwardly therefrom, each said gathered end having a metallic clip disposed in encircling relationship thereabout, said clips being positioned adjacent said product with said gathered ends protruding outwardly from the central hollow regions defined by said clips, respectively, the material underneath each clip being in ultrasonic vibratory energy induces swollen condition as characterized by intimate essentially void-free conformity thereof with said hollow regions, and being fused to form an essentially solid mass of material underneath the clips, respectively, the swollen condition of said gathered ends extending to areas generally immediately outwardly of said clips, respectively, to insure clip retention on said package, the portion of said gathered ends which is swollen being of sufficient integrity to maintain a substantially airtight closure at each end of said package even subsequent to removal of said clips from the package.