Pressed paperboard servingware with improved rigidity and rim stiffness

摘要

Products and methods of increasing the Rigidity and Rim Stiffness of disposable containers are provided. The containers have an outer flange portion extending outwardly with a brim portion sloping downwardly defining a declivity angle α with respect to a horizontal generally parallel to the bottom portion and generally include an outward turn at the periphery of the container. A preferred method of improving rigidity includes press-forming: (i) a brim transition portion adjoining the downwardly sloping brim portion of the container and (ii) an outwardly extending annular evert portion adjoining the brim transition portion extending outwardly at an eversion angle β of at least about 25 degrees with respect to the downwardly sloping brim portion of the flange.

主权项

1. A disposable servingware container press-formed from a generally planar paperboard blank, comprising:
a generally planar bottom portion; a sidewall portion extending upwardly and outwardly from the generally planar bottom portion; a brim portion extending outwardly from the sidewall portion; an evert portion extending outwardly from the brim portion; a first annular transition portion located between the generally planar bottom portion and a first end of the sidewall portion, the first annular transition portion having a radius of curvature R1; a second annular transition portion located between a second end of the sidewall portion and a first end of the brim portion, the second annular transition portion having a radius of curvature R2; the brim portion having a first generally straight section, a second generally straight section, and a third annular transition portion between the first and second generally straight sections, wherein the third annular transition portion has a radius of curvature R3, wherein the first generally straight section extends downwardly and outwardly from a first end of the second annular transition portion at an angle of 6 degrees to 12 degrees with respect to a horizontal that is substantially parallel to the bottom portion, and wherein the second generally straight section extends downwardly and outwardly at an angle of about 45 degrees to about 75 degrees with respect to a horizontal that is substantially parallel to the bottom portion; a fourth annular transition portion located between the second generally straight section of the brim portion and the evert portion, the fourth annular transition portion having a radius of curvature R4; and a characteristic diameter D, wherein a length of the second generally straight section of the brim portion is 0.003D to 0.005D.