High-Loft Absorbent Core With Dual SAPs for Fast, Low-Rewet Absorption
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Solution Overview
Problem
There is a need to improve the performance of absorbent cores in personal hygiene products, such as diapers, by enhancing absorption speed, capacity, and reducing rewet while maintaining low manufacturing costs.
Innovation Solution
The absorbent core comprises a high loft central layer with two types of superabsorbent polymers (SAP) distributed on its surfaces, where the first SAP has higher capacity and the second SAP has higher permeability, and is partially embedded within the porous nonwoven structure, with a wrapping layer to stabilize the SAP.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If a single type of SAP is used in the absorbent core, then the manufacturing process is simple, but the absorption speed and capacity cannot be optimized simultaneously
Solution Approach 1:
The patent applies local quality by using two different types of SAP particles with distinct properties in different locations within the absorbent core. The first SAP type is positioned in the first portion and the second SAP type in the second portion, allowing each region to contribute its specialized properties (capacity vs. speed) to the overall performance.
Solution Approach 2:
The patent employs composite materials by combining two different SAP particle types within the same absorbent core structure. This composite approach integrates the high capacity characteristics of one SAP type with the high absorption speed characteristics of another, achieving superior overall performance that neither material could provide alone.
2Quantity of substance
If high capacity SAP is used, then absorption capacity increases, but absorption speed decreases
Solution Approach 1:
The patent resolves this contradiction by assigning different SAP types to different portions of the absorbent core. The first SAP type with higher capacity is placed in the first portion, while the second SAP type with higher absorption speed is placed in the second portion, allowing both capacity and speed requirements to be met in their respective locations.
Solution Approach 2:
The patent segments the absorbent core into at least two distinct portions, each containing a different SAP type. This segmentation allows the core to function as multiple specialized zones working in parallel, where one zone optimizes for capacity and another optimizes for speed, thereby resolving the trade-off between these conflicting properties.
3Speed
If SAP particles are loosely distributed, then absorption speed is fast, but rewet increases
Solution Approach 1:
The patent applies local quality by creating different microenvironments for different SAP types. The first SAP type is distributed in a manner optimized for capacity, while the second SAP type is distributed to optimize speed while controlling rewet. Each portion's SAP distribution is locally optimized for its specific function.
Solution Approach 2:
The patent uses the distribution pattern as an intermediary mechanism to mediate between absorption speed and rewet control. By carefully controlling how the second SAP type is distributed in the second portion, the system achieves fast absorption while the distribution pattern itself acts as a regulator to prevent excessive rewet.
4Productivity
If multiple SAP types are used, then performance is optimized, but manufacturing complexity increases
Solution Approach 1:
The patent segments the absorbent core into distinct portions that can be manufactured and potentially assembled separately. This segmentation allows for simplified manufacturing of each portion with its specific SAP type, while the overall multi-SAP system achieves optimized performance through the combination of these segmented components.
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 with fast absorption and reduced rewet, providing improved wearer comfort and efficient fluid management.
Implementation Method 1
The absorbent core should be able to absorb and retain the exudates for a prolonged amount of time
Implementation Method 2
superabsorbent polymers (SAP) particles, also called absorbent gelling materials (AGM)
Implementation Method 3
SAP particles deposited on the surface of the high loft layer being at least partially distributed and immobilized within the pores of the high loft layer
Data Source
AI summary
An absorbent core for use in an absorbent article 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.