Polymeric Foam Absorbent Core for Gel-Blocking Mitigation
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing disposable absorbent articles face challenges with fluid transport due to phenomena like 'gel-blocking,' which reduces the effectiveness of absorbent core designs, particularly in designs that separate liquid storage and acquisition and distribution functions.
Innovation Solution
The development of an absorbent article comprising a polymeric foam with specific properties, such as an average cell size of at least 100 microns, a density of less than 3 lbs/ft3, and a gel content greater than 90%, combined with a second absorbent layer in fluid communication, enhances fluid transport by improving the absorption and distribution of aqueous fluids.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If superabsorbent polymers mixed with cellulose fibers are used for storing aqueous fluids, then absorption capacity is improved, but fluid transport deteriorates due to gel-blocking phenomenon
Solution Approach 1:
The absorbent core is divided into two distinct layers: a first layer comprising the polymeric foam material with superabsorbent polymer for absorption, and a second layer for fluid transport. This segmentation separates the absorption function from the transport function, allowing each layer to optimize its specific role without the gel-blocking effect limiting overall performance.
Solution Approach 2:
The polymeric foam material acts as an intermediary between the fluid source and the superabsorbent polymer. The foam's open-cell structure provides a pathway for fluid to reach the SAP particles while the foam itself contributes to absorption, mediating the fluid transport process and preventing direct gel-blocking of the SAP.
2Quantity of substance
If absorbent core designs separate liquid storage and acquisition and distribution functions into different layers, then absorption capacity is improved, but fluid transport deteriorates
Solution Approach 1:
The polymeric foam material in the first layer performs multiple functions simultaneously: it provides fluid acquisition through its hydrophilic properties, enables fluid distribution through its open-cell structure, and contributes to absorption capacity. This multi-functionality in the first layer complements the second layer's transport function, resolving the contradiction between separation and transport.
3Quantity of substance
If polymeric foam with high gel content is used to improve absorption, then absorption capacity is improved, but fluid transport deteriorates due to reduced flexibility
Solution Approach 1:
The polymeric foam is designed with specific local properties: large average cell size (at least 100 microns) in the pore structure to facilitate fluid transport, while maintaining high gel content (>90%) in the polymer matrix for absorption. This local differentiation of properties within the foam structure allows simultaneous optimization of both transport and absorption functions.
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 enhances the absorption capacity and fluid transport efficiency, reducing strike-through time and rewet, while maintaining the absorbent composite's absorption properties, suitable for applications like feminine hygiene and adult incontinence articles.
Implementation Method 1
Open celled polymeric foams have been described for use in disposable absorbent articles... improves the absorption and distribution of aqueous fluids
Implementation Method 2
a gel content greater than 90%... When a phenomena often referred to as 'gel-blocking' takes place
Data Source
AI summary
Absorbent articles are described comprising a first absorbent layer comprising a polymeric foam. In one embodiment, the polyurethane foam comprises the reaction product of a polymeric polyisocyanate component having an equivalent weight of no greater than 250 g/equivalent; and a polyol component. The polyol component comprises one or more polyether polyols such that the polyol component comprises an average equivalent weight ranging from 500 to 2000 g/equivalent; an ethylene oxide content ranging from 15-30 wt.-%; a secondary hydroxyl content of at least 55 wt.-% and less than 80 wt.-% of the total hydroxyl content of the polyol component; and less than 5 wt-% water. Also described are various composites comprising the polyurethane foam described herein in combination with another substrate such as a second absorbent layer, a fluid impervious backsheet, and/or a fluid pervious topsheet.