Flexible Container Stress Concentrator for Easy Opening
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Solution Overview
Problem
Existing flexible containers with easy-opening features, such as heat-shrinkable bags, face challenges in manufacturing complexity and risk of vacuum loss due to detachable tear tabs, and require improved designs for easy manual opening without damaging the contents.
Innovation Solution
A flexible container design featuring a plastic film enclosure with heat-sealable openings and tabs that concentrate stress on the seal, allowing easy manual opening by users without the need for cutting tools, and maintaining hermeticity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If detachable tear tabs are used for easy opening, then ease of operation is improved, but reliability deteriorates due to risk of vacuum loss
Solution Approach 1:
The opening tab is segmented with multiple openings (first opening for finger insertion, second opening for stress concentration) to enable controlled tearing. This segmentation allows the tab to be pulled apart easily while the tear propagates along the seal line, providing easy opening without compromising the main vacuum seal integrity.
Solution Approach 2:
The opening tab has non-uniform structure with different opening sizes and positions - the first opening is larger for finger access while the second opening is positioned to concentrate stress at a specific location on the seal. This local variation in structure enables controlled tear propagation at the desired location without affecting the overall seal integrity.
2Ease of operation
If complex tear tab structures are implemented, then ease of operation is improved, but device complexity increases
Solution Approach 1:
The opening tab is integrated directly into the flexible container structure during the same forming process, combining the tab function with the container body. The multiple openings are formed as part of the single-piece thermoplastic structure, eliminating the need for separate components or complex assembly steps, thus reducing manufacturing complexity while maintaining easy opening functionality.
Solution Approach 2:
The opening tab serves multiple functions: it provides finger insertion points for gripping, creates stress concentration zones for initiating tears, and guides the tear propagation path along the seal. This multi-functionality is achieved through a single integrated structure with strategically positioned openings, avoiding the need for multiple separate components.
3Ease of operation
If stress concentration is increased at the seal, then ease of operation is improved, but strength of the seal deteriorates
Solution Approach 1:
The opening tab is pre-formed with specific opening configurations during manufacturing, creating predetermined stress concentration zones. When the user pulls the tab, the stress is already concentrated at the intended tear initiation point, requiring minimal opening force. The seal strength is maintained because the stress concentration is localized to the tab region and propagates along the seal line without compromising the overall seal integrity.
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 enables easy, tool-free opening of flexible containers with reduced manufacturing complexity and minimized risk of vacuum loss, while maintaining the integrity of the packaged product.
Implementation Method 1
the openings being arranged to concentrate opening stress on the seal so that the seal is torn
Implementation Method 2
a seal closing the openable portion of the enclosure. The seal closing the openable portion of the enclosure may be a heat seal
Data Source
AI summary
A flexible container including opposing closed first and second edges, a closed third edge and an open side or end. The flexible container may include an unclosed area extending beyond one of the closed edges forming the flexible container. The unclosed area may include a first opening tab and a second opening tab configured to be pulled apart in order to initiate opening of the flexible container. The first opening tab and second opening tab may each include at least two openings. The opening may be positioned so as to channel a stress concentration proximate a heat seal. The flexible container may be formed of multi-layer film having a first outer layer, a second outer layer and directly adhered to the first outer layer an internal layer formed of a blend of at least two resin components that are partially compatible.