Superabsorbent Polymer Gel for Cellulose-Free Diaper Leakage
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Solution Overview
Problem
Current superabsorbents are inadequately suited for the new generation of cellulose-free diaper constructions, which require enhanced hydrogel properties to prevent urine leakage during micturition and optimize liquid distribution.
Innovation Solution
Development of particulate absorbent polymer materials with specific properties, including high centrifuge retention capacity and absorption under pressure, achieved through radical polymerization and surface post-crosslinking, to effectively immobilize and distribute absorbed liquids.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Volume of moving object
If superabsorbent particles are immobilized on substrate surface using thermoplastic fibers, then the absorbent core can be made thinner with reduced cellulose fiber content, but the ability to prevent urine leakage during micturition deteriorates
Solution Approach 1:
The patent applies parameter changes by modifying the surface properties of superabsorbent particles through post-crosslinking treatment. This changes the gel structure and surface characteristics of the particles, enabling them to effectively prevent urine leakage during micturition even in thin, cellulose-free absorbent cores. The crosslinking density and gel composition are adjusted to optimize both leakage prevention and absorption performance.
Solution Approach 2:
The patent creates a composite structure by combining superabsorbent particles with specific gel-forming components and thermoplastic fibers. The superabsorbent particles are treated to form a composite gel matrix that works synergistically with the thermoplastic fiber network to provide both structural integrity and leakage prevention, replacing the traditional cellulose fiber function.
2Quantity of substance
If cellulose fiber content is reduced in absorbent cores, then wearing comfort and packaging costs are improved, but the temporary liquid storage and transfer function deteriorates
Solution Approach 1:
The patent changes the parameters of superabsorbent particles through controlled crosslinking and gel formation. The gel structure is engineered to provide temporary liquid storage capacity, replacing the cellulose fiber function. The gel's swelling properties and network structure are optimized to hold liquid temporarily before transfer to the reservoir layer.
Solution Approach 2:
The patent introduces a gel-forming component as an intermediary between the superabsorbent particles and the liquid. This gel acts as a temporary storage medium, facilitating liquid retention and controlled release, thereby compensating for the removed cellulose fiber function in liquid storage and transfer.
3Quantity of substance
If superabsorbent content is increased to compensate for lost cellulose fiber function, then absorption capacity is maintained, but the ability to distribute liquid throughout the gel layer deteriorates
Solution Approach 1:
The patent utilizes porous gel structures formed by the crosslinked superabsorbent particles. The gel network creates interconnected pores that facilitate liquid distribution throughout the absorbent core. This porous structure allows liquid to penetrate and distribute evenly across the gel layer, preventing pooling and ensuring uniform absorption even with high superabsorbent content.
Solution Approach 2:
The patent adjusts the crosslinking parameters and gel composition to optimize liquid distribution. By controlling the gel's mesh size, swelling ratio, and surface hydrophilicity, the liquid can be effectively distributed throughout the gel layer while maintaining high absorption capacity with increased superabsorbent content.
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 new absorbent polymer materials provide improved leakage prevention and optimal liquid distribution within the diaper, enhancing the performance of cellulose-free absorbent cores.
Implementation Method 1
Superabsorbents are water-insoluble, cross-linked polymers that are capable of absorbing large amounts of aqueous liquids, in particular body fluids, preferably urine or blood, while swelling and forming hydrogels, and retaining them under pressure.
Implementation Method 2
superabsorbents or superabsorbent compositions, their application and their production are given by F. L. Buchholz and A. T. Graham (editors) in 'Modern Superabsorbent Polymer Technology'
Implementation Method 3
the superabsorbent/hydrogel's ability to effectively absorb the liquid during swelling and distribute it throughout the gel layer
Implementation Method 4
distribute it throughout the gel layer, while minimizing the amount of unbound urine in the diaper
Data Source
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AI summary
The invention relates to a particulate, absorbent polymer material comprising at least one of the following properties: i) a maximum APCi x 10 sec-value of >=1.6 for at least one number i selected from the group of the whole numbers from 2 to 12 (=APCmax); ii) a value for the sum of all APCi × 10 sec-values of >= 12 for all numbers i from the group of whole numbers from 2 to 12 (=APCsum); wherein the APCi x 10 sec-value is defined as follows: APCi × 10 sec=QIi × 10 sec-value2 ×PIi × 10 sec-value, wherein - the QIi x 10 sec-value value is the value of the source index determined according to the test method described herein i x 10 seconds after adding the 0.9 wt % of NaCl solution and - the PIi x 10 sec-value the value of the permeability index according to the test method described herein i x 10 seconds after adding the 0.9 wt % of NaCl solution. The invention also relates to an absorbent core comprising such a particulate absorbent material, to a hygiene product, to a method for producing an absorbent core and to an absorbent core that can be obtained by said method.