Polypropylene Package Triangular Pull Corner for Easy Opening
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Solution Overview
Problem
Existing polypropylene packages with 45° folded corners and parallel tear strips face difficulties in opening due to resistance from heat-sealed folds, making them hard to tear, especially when made of polyethylene, and short tear handles are cumbersome to grasp.
Innovation Solution
A package design featuring a triangular pull corner with pointed U-shaped tear strips, where the tear strips are secured within the shell and extend along the bottom, allowing easy gripping and minimizing resistance during opening, and the sides can be folded using various techniques to ensure secure sealing.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If parallel tear strips are placed close to the end of the pull corner, then the package can be opened easily, but the heat-sealed fold presents greater resistance to tearing
Solution Approach 1:
The pull corner is changed from a 45° fold (symmetric) to a triangular projection (asymmetric), which fundamentally alters the stress distribution during tearing. This asymmetric geometry allows the tear strips to be positioned optimally without creating a resistant fold, as the triangular shape naturally directs tearing forces away from the heat-sealed edges.
Solution Approach 2:
The tear strips are configured in a pointed U-shape rather than straight parallel lines, adding curvature and dimensional complexity to the tear path. This curved configuration allows the tears to propagate smoothly through the material without encountering the resistance created by straight folds, effectively navigating around the heat-sealed regions.
2Device complexity
If the pull corner is formed by 45° folds, then the package structure is simple, but it presents greater resistance to tearing due to heat-sealed folds
Solution Approach 1:
The pull corner is changed from a 45° fold (symmetric) to a triangular projection (asymmetric), which fundamentally alters the stress distribution during tearing. This asymmetric geometry allows the tear strips to be positioned optimally without creating a resistant fold, as the triangular shape naturally directs tearing forces away from the heat-sealed edges.
3Device complexity
If the tear handle is made very short, then the package structure is compact, but it is not easy to take hold of
Solution Approach 1:
The tear strips are merged with the triangular projection to form an integrated pulling element. The pointed U-shaped tear strips extend into the triangular projection, combining the structural function of the corner with the gripping function of the tear handle, creating a unified element that is both compact and easy to grasp.
Solution Approach 2:
The tear strips are configured in a pointed U-shape rather than straight parallel lines, adding curvature and dimensional complexity to the tear path. This curved configuration allows the tears to propagate smoothly through the material without encountering the resistance created by straight folds, effectively navigating around the heat-sealed regions.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The design facilitates easier opening of polypropylene packages by eliminating resistance from folds and providing a comfortable grip, ensuring reliable and efficient access to the contents without tearing issues.
Implementation Method 1
two tear strips disposed on and secured to the first sheet
Implementation Method 2
the sides of the shell being folded down thereon and heat-sealed
Data Source
AI summary
A sealed rectangular parallelepiped polypropylene conditioning package with fast tear-off opening for pasty products likely to melt into a semi-liquid state, in particular cheese, includes a first sheet (1) cut out along a suitable contour and having a rectangular shell-type shape for receiving the product and for providing a gripping corner (2) for opening the package, a cover sheet and two tear-off strips (5,6). The gripping corner (2) has a triangular projection formed on one of the sides of the first sheet cut out into an octagonal shape and the tear-off strips (5, 6) form a pointed U shape whereof the tip is located in the triangular projection, thereby making it easy and simple to open.