Discrete Acquisition Cells for Rapid Capillary Absorption
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Disposable absorbent products, such as infant diapers and adult incontinence briefs, face challenges in providing effective leakage resistance and rapid liquid absorption in ultra-thin structures, where the free volume required for capillary absorption is insufficient to handle the volume of liquid they need to contain, and diffusion into superabsorbent polymers is slow.
Innovation Solution
Incorporating discrete acquisition cells made from cellulosic materials that expand rapidly in one dimension upon contact with liquid, combined with superabsorbent polymer particles, to create a composite absorbent laminate that generates free volume for rapid capillary absorption and efficiently handles multiple doses of liquid.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Length of stationary object
If an ultra-thin absorbent core is used, then the product thickness is reduced and discretion is improved, but the free volume required for rapid capillary absorption becomes insufficient
Solution Approach 1:
The absorbent core is segmented into multiple functional layers: a liquid-permeable acquisition layer containing hydrophilic fibers for rapid initial absorption, a distribution layer with superabsorbent polymer particles for bulk absorption, and a backsheet layer for containment. This segmentation allows each layer to specialize in specific absorption functions, enabling rapid capillary action in the thin acquisition layer while the SAP layer provides volumetric absorption capacity.
Solution Approach 2:
The invention uses composite materials combining hydrophilic cellulose fibers with superabsorbent polymer particles in a layered structure. The hydrophilic fibers provide capillary channels for rapid liquid wicking, while the SAP particles provide high-capacity absorption. This composite approach allows the thin structure to achieve both rapid absorption and high liquid containment capacity.
2Quantity of substance
If superabsorbent polymer particles are used in an ultra-thin core, then large quantities of liquid can be absorbed, but the diffusion of liquid into the superabsorbent polymer is slow
Solution Approach 1:
Hydrophilic cellulose fibers serve as an intermediary between the liquid surface and the superabsorbent polymer particles. These fibers create capillary channels that rapidly conduct liquid to the SAP particles, bridging the gap between the liquid source and the absorption sites. This intermediary structure accelerates liquid transport to the SAP, enabling fast overall absorption despite the inherent slowness of diffusion into the polymer particles themselves.
3Device complexity
If a coherent sheet of material is used at a given basis weight, then the material structure is simple, but less free volume is generated compared to particulate forms
Solution Approach 1:
The acquisition layer is constructed as a porous nonwoven mat of hydrophilic cellulose fibers rather than a coherent sheet. This porous structure creates numerous capillary channels and void spaces that facilitate rapid liquid wicking through capillary action. The porous architecture provides significantly more free volume and surface area for liquid interaction compared to a dense coherent sheet of the same basis weight.
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 absorbent structure achieves rapid liquid uptake and absorption, reducing leakage risk by providing instantaneous free volume and effective liquid distribution, outperforming conventional materials in terms of absorbency and leakage prevention.
Implementation Method 1
The free volume required for rapid capillary absorption in an ultra-thin core
Implementation Method 2
discrete particles of a cellulosic material that can rapidly increase in at least one dimension when they come in contact with liquid
Implementation Method 3
diffusion of liquid into a superabsorbent polymer is slow and typically requires several minutes
Data Source
Figure 1~2
AI summary
An absorbent structure including a composite absorbent laminate is disclosed, with the structure suitable for use in disposable absorbent products such as for infant or incontinence care. Notably the laminate comprises discrete acquisition ceils each comprising particles of preferably ceiiulosic absorbent material. The absorbent structure further comprises particulate superabsorbent polymer which can either be biended with the particulate discrete acquisition cells in the absorbent laminate, or provided in a separate absorbent layer of the absorbent structure. The discrete acquisition cells desirably generate free voiume for rapid capillary absorption in an ultra-thin absorbent structure.