Superabsorbent Composite with Hydrophobic Coating for Gel Blocking
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Solution Overview
Problem
Existing absorbent composites face challenges in achieving high Column Absorbency Under Load (CAUL) and permeability simultaneously, leading to issues with liquid absorption and retention, particularly at higher concentrations of superabsorbent materials, which can result in gel blocking and excessive rewetting.
Innovation Solution
An absorbent composite is designed with a superabsorbent material having a CAUL above 10 g/g at 0.3 psi, incorporating a mixture of fibrous material and superabsorbent polymer distributed throughout the central absorbent layer, with upper and lower layers made from tissue or synthetic non-woven materials to enhance absorption and prevent gel blocking.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If superabsorbent material concentration is increased to improve absorption capacity, then absorption capacity is improved, but gel blocking occurs and permeability deteriorates
Solution Approach 1:
The patent changes the physical and chemical parameters of the superabsorbent material by applying a hydrophobic coating that modifies surface properties. This coating reduces the affinity of SAP particles for water, preventing excessive swelling and gel blocking while maintaining absorption capacity. The hydrophobic treatment alters the surface energy and wettability parameters of the SAP particles, allowing them to absorb liquid without forming blocking gels.
Solution Approach 2:
The patent creates a composite structure by combining superabsorbent polymer particles with hydrophobic coating materials. This composite approach integrates the high absorption capacity of SAP with the gel-blocking prevention properties of hydrophobic materials. The resulting coated particles exhibit both high absorption capacity and improved permeability, resolving the contradiction between absorption and gel blocking.
2Quantity of substance
If superabsorbent material concentration is increased to improve absorption capacity, then absorption capacity is improved, but permeability deteriorates
Solution Approach 1:
The hydrophobic coating changes the surface parameters of SAP particles, reducing their tendency to form dense gels that block permeability. By modifying the surface hydrophobicity, the coating allows liquid to pass through the absorbent core more easily while the interior SAP particles continue to absorb liquid, thus maintaining both high absorption capacity and good permeability.
Solution Approach 2:
The hydrophobic coating acts as an intermediary layer between the SAP particles and the liquid. This intermediate layer prevents direct excessive interaction between water and SAP surfaces, reducing gel formation while still allowing liquid transport. The coating mediates the interaction to maintain both absorption capacity and permeability.
3Reliability
If absorption under load is improved by increasing SAP concentration, then functional capacity is improved, but excessive rewetting occurs
Solution Approach 1:
The hydrophobic coating changes the absorption kinetics by controlling the rate at which SAP particles take up liquid. The coating creates a barrier that slows down water penetration to the SAP interior, allowing more controlled swelling and reducing the tendency for excessive rewetting. This parameter change maintains functional capacity while reducing harmful rewetting effects.
Solution Approach 2:
The hydrophobic coating provides beforehand protection against excessive rewetting by pre-modifying the SAP particle surfaces. The coating acts as a protective layer that prevents uncontrolled water absorption and gel blocking before they can occur, cushioning against the harmful effects of excessive rewetting while maintaining absorption capacity.
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 composite effectively absorbs and retains fluids, preventing excessive rewetting and leakage, while maintaining comfort and ease of use, by optimizing both absorption under load and permeability.
Implementation Method 1
superabsorbent materials are polymeric gelling materials that are capable of absorbing and retaining even under moderate pressure large quantities of liquid
Implementation Method 2
the particles or fibers may be described chemically as having a back bone of natural or synthetic polymers with hydrophilic groups... causing the superabsorbent polymer (SAP) to be highly hydrophilic
Implementation Method 3
Further absorption of liquid by the absorbent core must then take place via a diffusion process
Data Source
AI summary
The present invention relates generally to an absorbent composite for an absorbent article, and more particularly to an absorbent composite comprising fibrous material and superabsorbent material having a Column Absorbency Under Load (CAUL) above 10 g/g. Such an absorbent composite provides a superabsorbent material having superior AUL and permeability, thereby providing improved absorption and rewetting properties. An absorbent article that contains such a composite provides improved ability to absorb and retain fluids, thus preventing excessive rewetting and leakage and making the article more comfortable to wear.