International Paper Company

Gerald F Justice

Benjamin J Cassidy

Richard J Connor

A package including a flanged tray and a wrapper surrounding it. The tray typically contains a foodstuff such as a pie. The wrapper is formed of a rectangular, unitary blank of paperboard which is folded and wrapped aroung the tray, the wrapper being folded to the form of a tube with the tray therein. The wrapper includes two oppositely located latching flaps (24) whose free edges (28) are curved so as to match the curvature of the tray. The curved or arcuate latching flaps are initially folded downwardly more than 90 degrees from the plane of the blank. Other portions (16, 18) of the blank are bent upwardly along respective transverse fold lines (23), causing the arcuate latching flaps to bow inwardly and beneath the flanges of a tray (32) and contact the tray flanges (34). Portions (16, 18) of the wrapper are then folded beneath and on the sides of the tray and ends (17) are overlapped and glued together to finish the package. If the tray is rectangular instead of round or oval, the free edges (28) of the flaps (24) are straight.

Wrapper for a flanged tray

A method of heat activating the interior surfaces of the top closure, fin forming panels of a paperboard carton of the type shown in U.S. Pat. No. 4,732,275 to thereby render their PE coating tacky prior to folding the panels to form the carton top closure. The geometry of the two fin forming panels is such that their interior surfaces require a U-shaped heating pattern, as opposed to heating their entire areas. This U pattern is achieved by a specific hot air jet arrangement on an otherwise conventional nozzle block and by moving the nozzle towards and away from the carton as the carton moves past the nozzle block. The method also includes heating by a second nozzle block, to increase the rate of production of closed cartons. The fin forming panels of the cartons may also be preheated.

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Washingtonville, NY, United States of America

Gerald F Justice