High-Loft Absorbent Core with Dual-SAP Layering
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Solution Overview
Problem
There is a continuous need to improve the performance of absorbent cores in terms of absorption speed, capacity, low rewet, and wearer comfort while keeping manufacturing costs low, particularly in absorbent articles like baby diapers.
Innovation Solution
The absorbent core comprises a high loft central layer with two different types of superabsorbent polymer (SAP) particles distributed on its top and bottom surfaces, where the first SAP has higher capacity and the second SAP has higher permeability, and is partially embedded within the pores of the central layer, which is sandwiched between a top and bottom cover layer.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a single type of superabsorbent polymer is used in the absorbent core, then the structure is simple and manufacturing is easier, but the absorption performance cannot achieve both high capacity and high permeability simultaneously
Solution Approach 1:
The patent applies local quality by using different types of superabsorbent polymers in different regions of the absorbent core. Specifically, high capacity SAP is placed in the central layer while high permeability SAP is placed in the cover layers, allowing each region to perform its specific function optimally without compromising the overall structure
Solution Approach 2:
The patent segments the absorbent core into distinct functional layers with different SAP types. The central layer is separated from the cover layers, with each layer containing specifically selected SAP particles tailored to its functional requirements, thereby achieving specialized performance in each region
2Quantity of substance
If high capacity superabsorbent polymer is used to maximize absorption, then absorption capacity improves, but permeability decreases causing slow acquisition speed
Solution Approach 1:
The patent divides the absorbent core into functional zones: the central layer contains high capacity SAP for maximum absorption, while the cover layers contain high permeability SAP for rapid fluid acquisition. This spatial segmentation allows each SAP type to optimize its specific function without interfering with the other
Solution Approach 2:
Different SAP properties are locally optimized in different positions: high capacity SAP is localized to the central absorption zone, while high permeability SAP is localized to the cover layers that interface with the topsheet and backsheet, enabling fast fluid uptake at the boundaries and high capacity in the center
3Speed
If high permeability superabsorbent polymer is used to improve acquisition speed, then permeability improves, but absorption capacity decreases
Solution Approach 1:
The absorbent core is segmented into functional layers where high permeability SAP is confined to the cover layers for rapid fluid acquisition, while high capacity SAP is confined to the central layer for maximum absorption. This segmentation prevents the trade-off from affecting the entire structure
Solution Approach 2:
High permeability SAP is locally positioned in the cover layers where rapid fluid uptake is critical, while high capacity SAP is locally positioned in the central layer where maximum absorption is needed. Each location receives the SAP type best suited to its specific functional requirement
4Reliability
If multiple different superabsorbent polymers are used to achieve balanced performance, then absorption performance improves, but manufacturing complexity and cost increase
Solution Approach 1:
The patent segments the absorbent core into distinct layers (central layer and cover layers) that are processed separately with different SAP types. This segmentation allows for specialized SAP selection in each layer while maintaining a relatively simple overall manufacturing process through layer-by-layer construction
Solution Approach 2:
Different SAP types are locally applied to different layers based on their specific functional requirements. The central layer receives high capacity SAP while cover layers receive high permeability SAP, enabling optimized performance in each region without requiring complex manufacturing processes
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 achieves a balanced performance in terms of acquisition speed and rewet, with improved absorption capabilities and comfort, while maintaining cost-effectiveness.
Implementation Method 1
The absorbent core comprises two different types of superabsorbent polymer (SAP) particles deposited on the respective side of the high loft core, and which are at least partially distributed within the central layer
Implementation Method 2
a second superabsorbent polymer ('SAP2') in the form of particles deposited on the bottom surface of the high loft central layer... which are at least partially distributed within the pores of the central layer
Data Source
AI summary
An absorbent article having an absorbent core including a high loft central layer having deposited on two different surfaces thereon a first superabsorbent polymer SAP1 and a second superabsorbent polymer SAP2 in the form of particles that are at least partially distributed within the high loft layer. The SAP1 has a higher capacity than SAP2 and the permeability of SAP2 is more than 5×10-7 cm3·s/g.