James River Corporation of Virginia

Patrick H Wnek

Ronald P Marx

Denny R Garns

Denny R Grans

A method of forming a container from a flat, substantially homogeneous blank of fibrous substrate, comprising the steps of shaping the blank into a formed container having a bottom wall, an up-turned side wall extending from the bottom wall, a rim outwardly extending from the side wall and a lip downwardly curving from the rim and including a plurality of radially-extending, circumferentially-spaced pleats formed in the side wall, rim, and lip, each pleat including at least three layers of the blank; and applying sufficient heat and pressure to the side wall and rim to decrease the thickness thereof to less than that of the blank and to transform each pleat into a substantially integrated fibrous structure in which the constituent layers generally lack individual identity, each structure having a density greater than and a thickness substantially equal to adjacent areas of the side wall and rim.

Method of producing a rigid paperboard container

This invention is a paperboard container comprising a bottom wall, an upwardly extending side wall, a first curved portion joining the side wall to the periphery of the bottom wall, an outwardly extending rim, a second curved portion joining the rim to the periphery of the side wall, and a downwardly curved lip outwardly extending from the periphery of the rim. The container is integrally formed from a substantially homogeneous paperboard blank by a press such that the thickness of the side wall, second curved portion and rim is less than that of the bottom wall, first curved portion and lip. The container includes a plurality of densified regions radially extending through and circumferentially spaced about annular sections of the side wall, second curved portion and rim. The densified regions are formed from pleats including at least three layers of paperboard created during press forming of the blank which are subjected to sufficient pressure to reform the pleats into cohesive, fibrous structures having a density substantially greater than and a thickness substantially equal to adjacent areas of the side wall, second curved portion and rim.

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Menasha, WI, United States of America

Patrick H Wnek