Ultrasonic Elastic Ear Laminate for Stretch-Releasable Bonding
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Solution Overview
Problem
Existing absorbent articles face challenges in balancing strength, comfort, and extensibility due to conflicting properties of elastomeric laminates, where increased bonding for strength can compromise extensibility and vice versa.
Innovation Solution
A laminate design featuring a combination of permanent and releasable ultrasonic bonds, where the releasable bonds detach upon stretching beyond 5 mm, allowing the laminate to transition from a compressed to a pillow-like state, enhancing comfort and breathability while maintaining structural integrity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a continuous bond pattern is used to bond the backsheet to the absorbent article components, then bonding reliability is improved, but material usage efficiency deteriorates due to excessive material application in non-critical areas
Solution Approach 1:
The bond pattern is segmented into discrete islands distributed across the backsheet surface, rather than using a continuous bond layer. Each island serves as an independent bonding zone, concentrating adhesive material only where structurally necessary. This segmentation maintains bonding reliability through distributed bond points while dramatically reducing material application in non-critical areas, directly resolving the contradiction between reliability and material efficiency.
2Loss of substance
If a patterned bond pattern is used to reduce material usage, then material usage efficiency is improved, but bonding reliability deteriorates due to potential weak spots
Solution Approach 1:
The bond islands are strategically positioned at locations of highest structural stress and functional importance, with varying sizes and densities matched to local bonding requirements. High-stress areas receive larger or more numerous bond islands, while low-stress areas use smaller or fewer islands. This local quality approach ensures bonding reliability is maintained at critical interfaces while minimizing material usage overall, resolving the contradiction between patterned efficiency and reliability.
3Reliability
If material is applied uniformly across the entire backsheet surface, then bonding coverage is improved, but manufacturing cost deteriorates due to excessive material consumption
Solution Approach 1:
Instead of applying adhesive material uniformly and excessively across the entire backsheet surface, the invention applies material partially and selectively only at the discrete island locations where bonding is required. This partial action approach achieves sufficient bonding coverage through targeted application, dramatically reducing overall material consumption and manufacturing cost while maintaining adequate coverage at critical bonding interfaces.
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 laminate achieves improved comfort and breathability by transitioning from a compressed to a pillow-like state during use, while maintaining sufficient attachment and strength, addressing the balance of strength, comfort, and extensibility.
Implementation Method 1
a backsheet (140) bonded to the second components (122, 124, 126, 128)
Data Source
Figure 1~2A
Figure 2B~2C
Figure 2D~2G
AI summary
An absorbent article includes a first and second waist region and a crotch region disposed between the first and second waist regions. The absorbent article includes a chassis having a topsheet, backsheet, and an absorbent core disposed between the topsheet and the backsheet. At least one elastic ear comprising a laminate is joined to the chassis. The laminate is an ultrasonically bonded laminate of an elastomeric layer and a nonwoven layer. The bond pattern includes a plurality of discrete, primary ultrasonic bonds and a plurality of secondary ultrasonic bonds. The primary bonds permanently attach the layers of the laminate and the secondary bonds releasably attach the layers of the laminate. The secondary bonds release when the laminate is extended in the stretch direction.