Patent ID: 7527585
Filing Date: 2009-05-05
Classification: A44B,B31B,B65D

Abstract:
1. A method of manufacture comprising the following steps: (a) joining first and second zipper strips of a plastic zipper to web material, said first zipper strip comprising a first closure profile and a first flange extending from said first closure profile, said second zipper strip comprising a second closure profile and a second flange extending from said second closure profile, said first and second closure profiles in combination comprising at least three projecting elements, and said first zipper strip further comprising a third flange extending from said first closure profile in a direction opposite to that of said first flange, said first through third flanges being joined to said web material; (b) before or after step (a) has been performed, arranging said web material such that first and second sections are mutually opposed; (c) after steps (a) and (b) have been performed, applying heat and pressure or ultrasonic vibrations and pressure along first and second zones that are substantially orthogonal to said joined zipper strips and extend at least from said zipper strips to the portions of said first and second sections of said web material that are furthest away from said zipper strips, the heat and pressure or ultrasonic vibrations and pressure being sufficient to melt the portions of said web material that lie within said first and second zones, and to melt and flatten the portions of said zipper that lie within said first and second zones; (d) before step (c) is performed, applying heat and pressure or ultrasonic vibrations and pressure in first and second transition regions having intermediate portions that will be respectively overlapped by said first and second zones in step (c), heat and pressure or ultrasonic vibrations and pressure being applied to an extent that upon completion of step (d), the projecting elements of said closure profiles that are furthest apart from each other will become fused to respective portions of the other zipper strip in said first and second transition regions, and said first and second closure profiles will be heated but not flattened in said first and second transition regions, wherein upon completion of steps (c) and (d), said unflattened portions of said first and second closure profiles in said first transition region form first and second transition areas on opposite sides of a first flattened section of said first and second closure profiles, and said unflattened portions of said first and second closure profiles in said second transition region form third and fourth transition areas on opposite sides of a second flattened section of said first and second closure profiles; (e) after step (c) has been performed, applying pressure in said first and second transition regions to an extent that surface irregularities formed on said first through third flanges during step (c) are flattened without flattening said first through fourth transition areas; and (f) cutting said web material and said first and second zipper strips along first and second lines that respectively intersect said first and second zones and extend the full height of said web material.