Packaging containers

Abstract

This article is a packaging container formed by molding a sheet-like blank, such as a paper blank shown in the reference development diagram, using a press. The blank shown in the reference development diagram is folded in mountain folds indicated by the dashed lines and in valley folds indicated by the two-dot chain lines, and the blank is pressed during molding to form the shape of the packaging container. Furthermore, as shown in the enlarged left side view of part CC, the portion where the blanks overlap at the edge of the packaging container is pressed during molding, reducing the blank's thickness. As shown in the front view, left side view, cross-sectional view along line AA, and cross-sectional view along line BB, the upper surface of the edge is smooth and horizontal, with no steps along the entire periphery, so that it fits in the same plane. This allows for a highly airtight top seal using the upper surface of the edge of the packaging container, which can, for example, extend the shelf life of food and prevent liquid leakage. Furthermore, a synthetic resin sheet may be attached to the upper surface, inner surface, and bottom of the edge of the packaging container, thereby maintaining the shape of the packaging container and preventing liquid leakage. After being softened by heating, the synthetic resin sheet is adhered to the packaging container by compressed air forming or vacuum forming. If the synthetic resin sheet has barrier properties against oxygen, water vapor, etc., it enables long-term storage of food. If the synthetic resin sheet is attached in a way that makes it easy to peel it off from the packaging container, the paper packaging container and the synthetic resin sheet can be separated and disposed of.

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