Method of making extruded zipper strips and bags containing the same

Abstract

A method of making bags having a reclosable zipper between wall panels and extending between side edges at the top end of the bag, the zipper comprising a continuous length of extruded profile plastic strip folded upon itself for zipper closing interengagement of its profile parts, the profile strip portions being spot welded together at the fold in the strip which may be at one end of the side edges of the bag, such as a fold in the material which provides the walls of the bag. The strip may be notched out to facilitate folding. By differential mass, or differential spacing, or tilted biasing of profile parts of the zipper strip, and provision of a lateral flange of substantial width on the strip not only is interlocking of the profile parts facilitated, but an expedient is provided for restraining opening of the zipper by internal bag pressures, while permitting relatively easy opening of the bag from the outside, i.e. the top or mouth end of the bag. Proper orientation of the zipper strip relative to the mouth end of the bag is facilitated by differentiating the profile parts as by contrasting color.

Dependencies are inferred from the claim text.