Perforated Stretch Laminate Tear Resistance
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Solution Overview
Problem
Breathable stretch laminates used in hygiene products are prone to tearing due to perforations, which compromise their strength and integrity when stretched during manufacturing, use, or wear.
Innovation Solution
A perforation pattern with at least two adjacent columns of sloping perforations, where the first column's perforations slope in one direction and the second column's perforations slope in a different direction, with specific spacing and alignment to resist tear propagation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If the stretch laminate is perforated to improve breathability, then air permeability is improved, but tear strength deteriorates
Solution Approach 1:
The perforation pattern is segmented into multiple columns with alternating sloping directions. Each column contains pairs of perforations with specific spacing, creating a distributed pattern that prevents continuous tear propagation while maintaining breathability. The segmentation of the perforation structure into discrete, strategically positioned elements allows air passage while preserving structural integrity.
Solution Approach 2:
The invention employs asymmetric perforation patterns where adjacent columns have perforations sloping in opposite directions. This asymmetric arrangement creates a zigzag tear path that resists linear tear propagation. The non-uniform spacing and alternating orientations of perforation pairs throughout the pattern create structural asymmetry that enhances tear resistance while maintaining overall breathability.
2Ease of manufacture
If perforations are added to make the laminate breathable, then moisture escape is improved, but the laminate becomes inherently weak
Solution Approach 1:
The perforation pattern segments the moisture escape pathways into discrete, distributed openings arranged in columns with alternating slopes. This segmentation allows moisture to escape through multiple small pathways rather than large continuous openings, maintaining structural integrity while achieving breathability. The spaced arrangement of perforation pairs creates redundant escape routes that preserve strength.
Solution Approach 2:
The invention applies local quality by varying the perforation characteristics in different regions. Adjacent columns have different sloping directions and spacing, creating localized variations in the pattern. This local differentiation allows the laminate to maintain overall structural integrity while providing sufficient moisture escape pathways in each local region.
Data Source
Figure 1~2B
Figure 3A~3B
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AI summary
A stretch laminate and a method for reducing and/or preventing tearing in a stretch laminate, when the stretch laminate is stretched in a stretching direction, is disclosed. The stretch laminate has a perforation pattern. The perforation pattern has at least two columns. A first column has a plurality of pairs of perforations stacked one pair above the other pair. The perforations in each pair sloping in a first direction, and a first space separating one pair from the other pair. A second column has a plurality of pairs of perforations stacked one pair above the other pair. The perforations in each pair sloping in a second direction, and a second space separating one pair from the other pair. The first direction and the second direction may be different. A third space between the columns is no greater than the first or second space between perforation in the pair.