Gradient Nonwoven Topsheets for Absorbent Articles
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Solution Overview
Problem
Existing nonwoven topsheets for absorbent articles face challenges in preventing fluid backflow while maintaining rapid fluid acquisition and desirable physical properties like smoothness, cushioning, and bulkiness, with existing solutions not adequately addressing the need for cost-effectiveness and reduced fuzz generation.
Innovation Solution
A nonwoven sheet comprising a first hydrophobic layer and a second more hydrophilic layer, manufactured through forming fibrous webs with composite fibers and subjecting them to thermal treatment for bonding, which enhances fluid transfer and rewet prevention.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If a topsheet has an upper layer with relatively low fiber density and a bottom layer with relatively high fiber density, then fluid transfer from top surface toward bottom surface is enhanced, but body fluid flows back from absorbent core toward wearer's skin due to wearer's body weight
Solution Approach 1:
The patent applies local quality by creating distinct layers with different fiber densities and hydrophobicity characteristics. The topsheet has an upper layer with lower fiber density for rapid fluid acquisition and a bottom layer with higher fiber density for fluid transfer, while the intermediate layer has progressively increasing density. This gradient structure locally optimizes each layer's function to prevent backflow while maintaining rapid absorption.
Solution Approach 2:
The patent uses composite materials by combining different fiber types (hydrophobic and hydrophilic fibers) in specific layers. The intermediate layer contains both hydrophobic and hydrophilic fibers with progressively increasing hydrophilicity from upper to lower surface, creating a composite structure that guides fluid downward and prevents backflow toward the wearer's skin.
2Speed
If a nonwoven provides rapid fluid acquisition speed, then fluid absorption is efficient, but rewet prevention and fuzz generation control are not adequately addressed
Solution Approach 1:
The patent segments the nonwoven structure into multiple functional layers: an upper layer for rapid fluid acquisition, an intermediate layer with gradient density and hydrophilicity for fluid transfer and rewet prevention, and a bottom layer for bulk absorption. This segmentation allows each layer to specialize in specific functions, maintaining rapid acquisition while preventing rewet.
Solution Approach 2:
The patent applies parameter changes by progressively varying fiber density and hydrophilicity parameters from the upper surface through the intermediate layer to the lower surface. The intermediate layer has fiber density and hydrophilicity that progressively increase from upper to lower surface, creating a gradient that maintains rapid fluid acquisition while preventing rewet through controlled fluid distribution.
3Ease of operation
If a nonwoven maintains desirable physical properties like thickness, smoothness, and cushioning, then wearer comfort is improved, but cost-effectiveness and fuzz generation reduction are compromised
Solution Approach 1:
The patent applies local quality by providing different physical properties in different layers. The upper layer maintains smoothness and cushioning for wearer comfort, while the intermediate and bottom layers provide structural support and bulk. This localized optimization achieves comfort without requiring expensive materials throughout the entire structure, improving cost-effectiveness.
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 solution provides improved rewet prevention and maintains rapid fluid acquisition speed, along with increased initial thickness and reduced fuzz generation, while ensuring surface smoothness and comfort.
Implementation Method 1
the first fiber is hydrophobic and the second fiber and the third fiber are hydrophilic, and wherein the second layer is more hydrophilic than the first layer
Implementation Method 2
subjecting the complex fibrous web to thermal treatment in order to thermal bond at least a portion of the first, second, and third fibers
Data Source
AI summary
The present invention relates to a nonwoven comprising a first layer comprising a first fiber and a second fiber, and a second layer comprising a third fiber; wherein the first fiber is hydrophobic and the second fiber is hydrophilic, and wherein the second layer is more hydrophilic than the first layer; a method for manufacturing the nonwoven according to the present invention; and an absorbent article comprising a topsheet; and a backsheet joined to the topsheet, wherein the topsheet comprises the nonwoven according to the present invention.