Absorbent Core Second Sheet Design for Wetback Control
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing absorbent articles, such as pull-on-type diapers, face challenges in improving absorption rates while minimizing wetback and maintaining strength, especially after multiple urinations, as they are prone to leakage and discomfort due to insufficient hydrophilic non-woven cloths that lose their hydrophilic properties.
Innovation Solution
A second sheet is positioned under the top sheet and directly bonded to the liquid-holding material in the absorbing core, allowing urine to be quickly directed into the core without diffusion, and the core-wrapping sheet is made of a hydrophilic agent-washable non-woven cloth that becomes less hydrophilic after use, reducing wetback while maintaining strength.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If a hydrophilic non-woven cloth is used to cover the liquid-holding material, then the absorption rate is improved, but wetback occurs after multiple urinations as the cloth loses its hydrophilic properties
Solution Approach 1:
The patent segments the non-woven cloth into two functional regions: a hydrophilic first sheet in contact with the liquid-holding material for absorption, and a less hydrophilic second sheet facing the top sheet to prevent wetback. This segmentation allows each region to perform its specific function optimally without interfering with the other.
Solution Approach 2:
The patent applies local quality by making different parts of the non-woven cloth have different hydrophilic properties. The first sheet region maintains high hydrophilicity for rapid urine absorption, while the second sheet region has reduced hydrophilicity to prevent wetback, creating localized functional zones within the same structure.
2Object-affected harmful factors
If the non-woven cloth becomes less hydrophilic to reduce wetback, then wetback is reduced, but the absorption rate decreases
Solution Approach 1:
The non-woven cloth is divided into functional segments where the first sheet portion maintains hydrophilicity for absorption while the second sheet portion becomes less hydrophilic to prevent wetback, allowing both contradictory requirements to be satisfied in different locations.
Solution Approach 2:
Different hydrophilic properties are assigned to different local regions of the non-woven cloth: the first sheet has high hydrophilicity localized at the absorption interface, while the second sheet has reduced hydrophilicity localized at the wetback prevention interface.
3Stability of the object's composition
If the absorbing core is covered entirely with a hydrophilic sheet, then deformation is prevented, but wetback cannot be sufficiently reduced when body pressure is applied
Solution Approach 1:
The core-wrapping sheet is designed with local quality variation: the first sheet portion in contact with the liquid-holding material provides stability and hydrophilicity, while the second sheet portion facing the top sheet has reduced hydrophilicity to prevent wetback under body pressure, allowing both stability and wetback prevention.
Solution Approach 2:
The core-wrapping sheet is segmented into functional regions where the first sheet segment provides structural stability and absorption support, while the second sheet segment provides wetback resistance, enabling the core to maintain both stability and prevent wetback simultaneously.
4Productivity
If a second sheet is added to improve absorption rate and reduce wetback, then absorption performance is improved, but the structure of the absorbing core becomes more complex
Solution Approach 1:
The patent merges the second sheet with the existing non-woven cloth structure, making it an integrated part of the absorbing core rather than a separate component. This merging approach improves absorption and reduces wetback while minimizing the increase in structural 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
This design enhances absorption rates and reduces wetback, providing comfort and preventing leakage in pull-on-type diapers by directing urine effectively into the liquid-holding material and maintaining core strength even after repeated use.
Implementation Method 1
urine is directly drawn from the second sheet through the connecting area into the absorbing core
Implementation Method 2
the absorber is covered with a non-woven cloth from which a hydrophilic agent readily washed away. This loss of the hydrophilic agent changes the hydrophilic non-woven cloth less hydrophilic after absorption of urine
Data Source
AI summary
An absorbent article has an absorbing core and a liquid-permeable second sheet disposed on the absorbing core. The absorbing core includes a liquid-holding material and a liquid-permeable core-wrapping sheet. The core-wrapping sheet covers the liquid-holding material, but a portion of a top-side surface of the liquid-holding material is exposed. The second sheet contacts the liquid-holding material at the exposed portion. The second sheet is placed in direct contact with the cellulose fibers of the liquid-holding material, and liquid permeates from the second sheet into the liquid-holding material. Also, deformation of the liquid-holding material is prevented by the hydrophilic core-wrapping sheet covering the liquid-holding material.