James River Corporation of Virginia

James River Corporation of America

Denny R Garns

Mark B Littlejohn

Ronald P Marx

James O Cheshire

Patrick H Wnek

Erland S Sandstrom

A container formed from a unitary paperboard blank having a substantially planar inner region, a sidewall region and a rim region formed about the periphery thereof is disclosed. The sidewall region includes a generally annular region flaring upwardly and outwardly from a periphery of the planar inner region and a first frusto-conical region adjoining the annular region with the frusto-conical region sloping outwardly and upwardly from the annular region. The rim region includes an outwardly flaring arcuate annular region adjoining an outer periphery of the first frusto-conical region, and a second frusto-conical region extending substantially tangentially from the arcuate annular region. The second frusto-conical region extends outwardly and downwardly at an angle of about 6.degree. to about 12.degree. and preferably about 6.degree.-10.5.degree. relative to the plane defined by the planar inner region. The rim of the container may further include an outwardly and downwardly flaring frusto-conical lip adjoining an outer periphery of the second frusto-conical region in order to aid in grasping of the paperboard container by the consumer. Additionally, a plurality of radially extending mutually spaced pleats are also formed in the rim region and are internally bonded with portions of the rim region during formation of the paperboard container by a die press. During the fabrication of the paperboard material for forming the aforementioned container, the paperboard material is impregnated with a sizing adhesive equivalent to at least 6 pounds of starch per 3,000 ft.sup.2 ream of paperboard material such that during the press forming of the paperboard containers between respective dies, the pleats adhere to respective portions of the pleats and rim, thereby maintaining the integrity of the pleats during use of the container by the consumer by resisting the opening of the pleats.

Rigid paperboard container

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

Growing community of inventors

Appleton, WI, United States of America

Denny R Garns