Absorbent Fibrous Web Density Profile for Liquid Management
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Solution Overview
Problem
Current disposable absorbent articles, such as diapers and sanitary napkins, face limitations with airfelt as an absorbent core material due to low integrity, tendency to bunch or rope when wet, and inability to provide adequate capillary work potential, leading to suboptimal liquid acquisition and retention.
Innovation Solution
The development of absorbent members with a controlled density profile, achieved through mechanical deformation processes that create fibrous layers with varying densities, allowing for improved liquid acquisition, flexibility, and fluid retention without the need for costly binder materials or complex processing.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If airfelt is used as an absorbent core material, then the material can be easily manufactured, but it has low integrity and bunches when wet
Solution Approach 1:
The patent applies parameter changes by controlling the density distribution within the absorbent core. The core is designed with a density gradient where the middle portion has a higher density than the outer portions. This density parameter modification improves structural integrity and prevents bunching while maintaining ease of manufacture through the airlaid process.
Solution Approach 2:
The patent implements local quality by creating different density zones within the absorbent core. The middle portion is denser while the outer portions are less dense, allowing each region to perform its specific function - the dense middle provides structural support and integrity, while the less dense outer portions facilitate liquid acquisition and distribution.
2Ease of manufacture
If airfelt is used as an absorbent core material, then the manufacturing process is simple, but it has low density and cannot provide adequate capillary work potential
Solution Approach 1:
The patent modifies the density parameter by creating a controlled density gradient within the absorbent core during the airlaid manufacturing process. The middle portion is formed with higher density to provide adequate capillary work potential, while maintaining overall simplicity in the manufacturing process through continuous web formation.
3Reliability
If binder materials and super-absorbent polymers are added to airfelt to improve strength, then the material gains integrity, but the cost and processing complexity increase significantly
Solution Approach 1:
The patent extracts or eliminates the need for binder materials and super-absorbent polymers by relying on the engineered density gradient structure alone. The higher density middle portion provides structural integrity through its physical configuration rather than chemical binders, simplifying the material composition and processing while maintaining reliability.
4Reliability
If a density gradient structure is created in the absorbent core, then liquid acquisition and retention improve, but the manufacturing process becomes more complex
Solution Approach 1:
The patent implements parameter changes by controlling the density distribution during the airlaid web formation process. The density gradient is created through process parameters such as fiber deposition control and compression variations, allowing the density profile to be established during standard manufacturing without adding significant processing complexity.
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 controlled density profile enhances the absorbent members' ability to manage liquids effectively, reducing rewet and improving integrity, while eliminating the need for separate layers and adhesives, thus providing improved performance and cost-effectiveness.
Implementation Method 1
Airfelt typically has a low density and cannot provide as much capillary work potential as a higher density material
Data Source
AI summary
Absorbent members and methods of making the same are disclosed. In one embodiment, the absorbent member is a unitary absorbent fibrous web having a density profile through its thickness. In such an embodiment, the density profile may be relatively centered through the thickness of the web and the maximum density of the web is located between about 35% and about 65% of the distance through the thickness of the web.