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US 4,437,293 AGranted
Method and apparatus for making a reclosable package
AssigneeW. R. Grace & Co., Cryovac Div.
InventorPhilip A. Sanborn, Jr.
Life of this patent
Estimating the term…
Abstract
A reclosable package, e.g. for food products, is made by sealing one side of a closure strip to a first thermoplastic sheet; enclosing a product between that first sheet and a second thermoplastic sheet with the closure strip inside the enclosure; and, sealing another side of the closure strip to the second sheet while the strip and product are so enclosed.
Claims2
A method for making a reclosable package from thermoplastic materials comprising the steps of:
- (a) providing a formable web, a covering web, and a closure strip;
- (b) forming a cavity with a peripheral flange in said forming web so that said closure strip remains on a portion of said peripheral flange;
- (c) advancing the forming web and closure strip towards each other;
- (d) sealing the lower surface of the closure strip to the forming web longitudinally in the direction of travel of the forming web;
- (e) indenting a portion of said closure strip by the application of heat and pressure at intervals spaced apart by approximately the desired length of the package;
- (f) placing a product in said cavity;
- (g) covering said product with said covering web;
- (h) evacuating the space between said webs;
- (i) sealing the webs together with longitudinal and transverse seals, one longitudinal seal being adjacent and parallel to but spaced apart from the closure strip with the closure strip within the periphery of the seals, and the transverse seals being made across the closure strip where a portion of the strip had been indented;
- and
- (j) sealing the upper surface of the closure strip to the covering web.
8 more elements
Dependencies are inferred from the claim text.