Polyethylene Tear Tape Density Profile for Clean Bag Opening
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Solution Overview
Problem
Existing polyethylene-based tapes for packaging bags often stretch instead of rupturing when torn, leading to unfavorable appearance and difficulty in forming an opening, especially in mono-material production aimed at enhancing recyclability.
Innovation Solution
The tape is made of a resin composition with polyethylene as the main component, featuring thin portions with higher density than thick portions, reducing ductility and ensuring smooth tearing along these sections.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If a thin portion is provided in the tape to enable easy tearing, then the opening formation is facilitated, but the thin portion stretches instead of rupturing when the bag body is torn
Solution Approach 1:
The patent applies parameter changes by modifying the density parameter of the thin portion. The thin portion is formed with a density of 0.93 g/cm³ or higher, which is higher than the surrounding thick portions. This density parameter change reduces the ductility of polyethylene in the thin portion, causing it to rupture cleanly rather than stretch when torn, thereby resolving the contradiction between ease of opening and favorable appearance.
2Manufacturing precision
If a thin portion is provided to guide tearing, then the tearing position is controlled, but the thin portion stretches instead of being ruptured
Solution Approach 1:
The patent changes the density parameter of the thin portion to 0.93 g/cm³ or higher through controlled formation during the extrusion process. This parameter change directly affects the mechanical properties of the thin portion, reducing its ductility while maintaining its function as a tearing guide. The high-density thin portion ruptures at the intended position without excessive stretching, simultaneously achieving precise tearing position control and appropriate strength characteristics.
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 tape can be easily torn along the thin portions, facilitating easy opening of the bag body while maintaining a favorable appearance and promoting recyclability through mono-material construction.
Implementation Method 1
the density of the thin portion is higher than the density of the first and second thick portions, reducing the ductility of polyethylene which is the main component of the resin composition
Data Source
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AI summary
A tape having a cross sectional profile including first and second thick portions and a thin portion provided between the first and second thick portions is provided. The first and second thick portions and the thin portion are made of a resin composition whose main component is polyethylene. The density of at least a part of the thin portion is higher than a density of the first and second thick portions.