Thin wall reclosable bag material and method of making same

A method of making bag material for providing bags with flexible sidewalls and reclosable separable plastic profile bag mouth closure means, comprising:

• advancing prefabricated thin and flexible bag sidewall sheet material continuously along an assembly path;
• providing prefabricated closure strips having base portions carrying separably interlockable complementary resilient plastic profiles that are generally aligned with said base portions and the base portions provided with lateral pull flange extensions of substantially greater thickness than said sheet material extending away from said profiles from one side of each of said base portions and with the opposite side of each base portion being generally aligned with its profile;
• continuously advancing said closure strips along said path and into laminar engagement with bag top mouth-opening-defining longitudinally marginal portions of said material;
• continuously joining said base portions and said lateral pull flange extensions in laminar relation assembly with said marginal portions and with the distal edges of said pull flange extensions directed toward the longitudinal edges of said marginal portions;
• and while said assembly continues advancing, uninterruptedly permanently securing said pull flange extensions and said base portions in said assembly with said marginal portions;
• effecting said permanently securing by applying heat to and through the sheet material marginal portions in laminar engagement with said base portions and said pull flange extensions and thereby causing fusion of said marginal portions to said base portions and to said pull flange extensions;
• and
• controlling and limiting the depth of penetration of the heat through said marginal portions into said base portions and into said pull flange extensions and thereby avoiding warpage and/or profile distortion of the permanently secured assembly.

Material for bags with flexible sidewalls having reclosable separable plastic profile bag mouth closure means, comprising:

• flexible bag sidewall sheet material having bag top mouth-opening-defining marginal portions;
• bag mouth closure means comprising strips having base portions carrying separably interlockable complementary resilient plastic profiles that are generally aligned with said base portions;
• lateral pull flange extensions, of substantially greater thickness than said sheet material, extending away from one side of each of said base portions and with the opposite side of each base portion being generally aligned with its profile;
• said sheet material being of less than 2 mil thickness, and said pull flange extensions being of at least 3 mil thickness;
• and means comprising a heat seal permanently securing said base portions of said closure strips and said pull flange extensions in laminar relation assembly with said marginal portions of said sheet material and with the distal edges of said pull flange extensions directed toward the bag top edges of said marginal portions, so that when the bag material is formed up into bags, the bags will have laminated pull flange assemblies of a thickness which is the sum of said sheet material marginal portions and said greater thickness pull flange extensions of said closure strips and will therefore provide pull flanges which are of substantially greater than twice the thickness of said sheet material.