Absorbent Core Segmentation for Wet Structural Integrity
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Solution Overview
Problem
Current absorbent cores for personal hygiene products, such as diapers, face challenges in maintaining structural integrity when wet and require significant material, leading to cost and environmental concerns, while also needing to optimize fluid handling performance.
Innovation Solution
A new absorbent core structure comprising a first absorbent layer with cross-linked cellulose fibers and a second layer with superabsorbent polymer particles, both covered by a fibrous layer of thermoplastic adhesive material, which improves resilience and fluid absorption while minimizing material usage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If a blend of comminuted wood pulp with superabsorbent polymer particles is used, then absorbent capacity is improved, but structural integrity when wet deteriorates and material consumption increases
Solution Approach 1:
The absorbent core is divided into two separate absorbent layers instead of using a blended mixture. The first layer contains cross-linked cellulose fibers and the second layer contains superabsorbent polymer particles, with each layer maintaining its own structural integrity while working together for enhanced absorbency.
Solution Approach 2:
Each absorbent layer is constructed as a composite material system. The first layer combines cross-linked cellulose fibers with a fibrous layer of thermoplastic adhesive material, while the second layer combines superabsorbent polymer particles with the same fibrous adhesive layer, creating composite structures that maintain strength when wet.
2Quantity of substance
If traditional mixed cores with wood pulp and SAP are used, then absorbent capacity is improved, but material consumption and cost increase
Solution Approach 1:
The core separates the two absorbent materials into distinct layers, allowing each material to be used in its optimal form without requiring excessive amounts of less effective materials like comminuted wood pulp, thereby reducing overall material consumption.
Solution Approach 2:
The invention changes the physical and chemical parameters of the cellulose fibers by using cross-linked cellulose instead of comminuted wood pulp. This parameter change enables the cellulose to provide both absorbency and structural support, reducing the need for additional materials.
3Productivity
If the upper acquisition layer nonwoven fully covers the lower acquisition layer, then liquid acquisition is improved, but unbound fibers may reach wearer skin through apertured topsheet
Solution Approach 1:
The invention extracts and removes the problematic lower acquisition layer from the traditional structure. Instead of having a separate lower acquisition layer that could shed fibers, the cross-linked cellulose fibers are integrated directly into the first absorbent layer, eliminating the source of unbound fibers while maintaining liquid acquisition functionality.
Solution Approach 2:
The fibrous layer of thermoplastic adhesive material acts as an intermediary that binds the cross-linked cellulose fibers and superabsorbent polymer particles, preventing fiber migration through the apertured topsheet while still allowing liquid to be acquired and distributed effectively.
4Quantity of substance
If chemically cross-linked cellulose fibers are used in lower acquisition layer, then liquid retention is improved, but superabsorbent polymers have difficulty dewatering the layer
Solution Approach 1:
The invention segments the liquid retention and dewatering functions into separate layers. The first layer with cross-linked cellulose fibers handles liquid retention and acquisition, while the second layer with superabsorbent polymer particles handles dewatering, allowing each material to optimize its specific function without interference.
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 core structure enhances fluid handling performance, reduces leakage, and maintains integrity under wet conditions, achieving better dryness and comfort while minimizing material consumption.
Implementation Method 1
Absorbent cores can expand several times their initial volumes when wet
Implementation Method 2
superabsorbent polymer particles (SAP), also called absorbent gelling materials (AGM)
Implementation Method 3
the lower acquisition layer may tend to retain liquid due to the hydrophilicity and the pore size of the chemically cross-linked cellulose fibers
Implementation Method 4
pore size of the chemically cross-linked cellulose fibers
Implementation Method 5
a fibrous layer of thermoplastic adhesive material (4) covering the layer of superabsorbent polymer particles (7)
Data Source
AI summary
An absorbent core suitable for use in an absorbent article comprising: a first absorbent layer, the first absorbent layer comprising a first substrate, and a layer of cross-linked cellulose fibers deposited on the first substrate, a second absorbent layer, the second absorbent layer comprising a second substrate, a layer of superabsorbent polymer particles deposited on the second substrate and a fibrous layer of thermoplastic adhesive material covering the layer of superabsorbent polymer particles. The first and second absorbent layers being combined together such that at least a portion of the fibrous layer of thermoplastic adhesive material contacts at least a portion of the layer of cross-linked cellulose fibers of the first absorbent layer.