Absorbent Article Joining Portion Segmentation for Crack Prevention
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Solution Overview
Problem
Existing absorbent articles face difficulties in removing the article without breaking the sheet members outside the joining portion, leading to potential exposure of the absorbent body or leakage due to cracks in the fused areas.
Innovation Solution
The absorbent article features a joining portion with a core and circumferential wall structure, where the circumferential wall portion is strong and less likely to break, allowing for controlled separation of the stomach-side and back-side portions along the longitudinal direction, with a specific ratio of short-gap to long-gap regions in the peel test ensuring even stress distribution.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If the joining portion is formed with multiple fused portions using ultrasonic sealing, then the joining strength is improved, but the risk of crack propagation to non-joining portions increases during removal
Solution Approach 1:
The joining portion is divided into multiple discrete fused portions spaced along the longitudinal direction, rather than forming a continuous seal. This segmentation allows the sheet members to be pulled apart at the gaps between fused portions during removal, preventing crack propagation to non-joining areas while maintaining sufficient joining strength through the distributed fused sections.
Solution Approach 2:
The sheet member structure is designed with localized variations in properties: the fused portions provide high strength and rigidity, while the gaps between fused portions provide flexibility and separation capability. This local differentiation of structural properties enables simultaneous achievement of strong joining and safe removal without crack propagation.
2Ease of operation
If the sheet members are continuously pulled apart in the longitudinal direction during removal, then the separation process is simplified, but breakage of sheet members in non-joining portions occurs
Solution Approach 1:
The joining portion is pre-designed with gaps between fused portions that serve as predetermined separation paths. During removal, the sheet members naturally separate at these pre-configured gap locations rather than requiring forceful separation that could cause unintended breakage. The structure itself guides the separation process.
3Strength
If the circumferential wall portion is made strong and rigid, then the joining portion resists deformation, but the ability to separate continuously during removal is reduced
Solution Approach 1:
The circumferential wall is segmented into discrete sections between fused portions, creating a structure that is rigid where needed (at fused portions) but flexible where needed (at gaps). This segmentation allows the structure to maintain joining strength while enabling continuous separation during removal through the gap 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
This configuration enables easy and continuous separation of the absorbent article without breaking the sheet members outside the joining portion, reducing the risk of leakage and improving the removal process.
Implementation Method 1
the joining portion (sealing portion) is formed using a sealing device including an ultrasonic horn and an anvil. In this method, while the conveyance of sheet members for the stomach-side portion and the back-side portion, when predetermined places for the joining portion to be formed in these sheet members pass through the gap between the ultrasonic horn and the anvil, the predetermined places are pinched and fused with the ultrasonic horn and the anvil
Data Source
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AI summary
The purpose of the present invention is to make a sheet member of an absorbent article less susceptible to tearing when taking off the absorbent article and allow the ventral side portion and dorsal side portion to be appropriately separated.. This absorbent article comprises a ventral side portion (11) and a dorsal side portion (13) and includes bonded portions (14a) formed by the lateral ends (11e, 13e) of the ventral side portion and the dorsal side portion being longitudinally placed on top of one another in a thickness direction and bonded to each other. The bonded portions include a plurality of fused portions (30) that are longitudinally arranged. Each fused portion includes a core portion MC at which a ventral side sheet member and a dorsal side sheet member are fused in the thickness direction and a surrounding wall portion SW which extends tubularly in the thickness direction from the peripheral edge of the core portion with the ventral side sheet member and the dorsal side sheet member being fused in the thickness direction thereat. In a peel strength test for the bonded portion, a ratio a/b of 0.5 to 2.0 is obtained for the ratio of the area a of the narrow spacing region and the area b of the wide spacing region in the region bounded by a graph plotting the relationship between the load between jigs that hold a sample compared against the spacing between the jigs, the narrow spacing region and the wide spacing region being separated at the maximum load spacing as a boundary.