Pulpless Absorbent Core Elastic Strand Valleys
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Solution Overview
Problem
Conventional absorbent core forming processes face challenges in balancing air flow and vacuum to retain cellulose pulp, leading to inefficiencies in superabsorbent material distribution and retention, particularly in high-speed manufacturing environments, and result in difficulties in controlling the bulk and distribution of superabsorbent polymers within the core.
Innovation Solution
The development of a pulpless absorbent core formation method using elastic strands coupled with nonwoven layers, where the elastic strands are stretched and relaxed to create valleys for superabsorbent polymer deposition, allowing for controlled expansion and improved liquid retention and distribution, and the core can be stretched in specific directions to enhance fit and functionality.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If conventional air laying techniques are used to form absorbent cores with cellulose pulp, then the cores can be formed continuously, but the distribution and retention of superabsorbent material becomes uncontrolled and inefficient
Solution Approach 1:
The absorbent core is segmented into discrete zones using elastic strands that create separated pockets or channels. These segments are formed by stretching elastic strands between fixed points on the carrier web, creating distinct regions where superabsorbent material can be precisely deposited and retained without mixing with adjacent zones, thereby improving distribution control while maintaining continuous production
Solution Approach 2:
The elastic strands are stretched and fixed to the carrier web before superabsorbent material is deposited. This preliminary action creates pre-formed pockets and channels that guide and contain the superabsorbent material in specific locations, ensuring controlled distribution before the actual material application occurs during high-speed manufacturing
2Reliability
If more superabsorbent material is added to increase absorbency, then liquid retention improves, but the bulk of the core increases requiring thicker diaper designs
Solution Approach 1:
Superabsorbent material is concentrated in specific local zones defined by the elastic strand pockets rather than being uniformly distributed throughout the entire core. This local quality approach places high concentrations of superabsorbent material only where liquid contact is most likely to occur, improving liquid retention while minimizing overall core bulk and enabling thinner diaper designs
Solution Approach 2:
The elastic strands create a pneumatic-like structure with pockets and channels that trap and hold superabsorbent material in specific locations. When liquid is applied, these pockets expand and contain the superabsorbent material, maximizing its liquid retention capability within a compressed volume, thereby improving absorbency without increasing core bulk
3Manufacturing precision
If elastic strands are stretched tightly to create small pockets, then superabsorbent material distribution is controlled, but the flexibility and fit of the final product is reduced
Solution Approach 1:
The elastic strands are stretched to a controlled degree during manufacturing to create pockets for material deposition, then allowed to partially relax. This dynamic approach maintains the structural definition needed for precise material distribution while retaining enough elasticity in the strands to provide flexibility and adaptability in the final product fit
Solution Approach 2:
The tension and stretch ratio of the elastic strands are optimized to specific parameter ranges that balance two competing requirements: sufficient stretch to create well-defined pockets for controlled material deposition, and sufficient residual elasticity to maintain product flexibility and fit. By changing the physical parameters of the elastic strands (material composition, strand diameter, stretch ratio), both precision and adaptability are achieved
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 approach enables better control over superabsorbent polymer distribution, reduces waste, and enhances the absorbency and flexibility of the absorbent core, allowing for thinner diaper designs while maintaining effective liquid management and improved product fit.
Implementation Method 1
elastic strands are stretched and relaxed to create valleys for superabsorbent polymer deposition
Implementation Method 2
the de-tensioning of the elastic creates valleys or depressions in the first material layer which can capture the superabsorbent material
Implementation Method 3
superabsorbent polymer material provided in gaps between adjacent elongated elastic members
Implementation Method 4
enhances the absorbency and flexibility of the absorbent core
Data Source
AI summary
A pulpless core is provided with flexibility for superabsorbent expansion by using elastic strands stretched and coupled to a nonwoven layer, and then relaxed partially to create receiving valleys (puckers) and the puckers are provided with superabsorbent polymer, and then a layer of nonwoven or acquisition film can be coupled on top of nonwoven/elastic/sap carrier layers to create an absorbent core laminate. A tubular core can be created and placed into a product with or without additional absorbent material between adjacent tubular members. A printed back sheet corresponding to either the tubular core shape, or void spaces between tubular members can be provide. A forming drum pocket can be profiled to match tube or tube shaped zones and elastic placements between adjacent tubes, if desired.