Apertured Non-Woven Surface Sheet for Absorbent Articles
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Solution Overview
Problem
Conventional absorbent articles face challenges in efficiently transferring body fluids to the absorbent body while minimizing backflow, due to issues with fluid permeability and anti-backflow properties, particularly when the skin-contacting surface is water-repellent and the non-skin contacting surface is hydrophilic.
Innovation Solution
A two-layer structured apertured non-woven fabric is used as the liquid permeable surface sheet, with a hydrophilic upper layer on the skin side and a water-repellent lower layer on the non-skin side, featuring apertures that facilitate smooth fluid transfer and reduce backflow by creating a capillary force gradient.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the skin-contacting surface is made water-repellent and the non-skin contacting surface is made hydrophilic, then the water-repellent layer can prevent backflow of body fluid, but the body fluid is hardly transferred to the absorbent body and side leakage occurs
Solution Approach 1:
The surface sheet is divided into multiple layers with different properties: a water-repellent layer on the skin-contacting side for preventing backflow, and a hydrophilic layer on the non-skin side for facilitating fluid transfer. This segmentation allows each layer to perform its specific function optimally without compromising the other.
Solution Approach 2:
Different regions of the surface sheet are given different properties: the skin-contacting surface is made water-repellent to prevent backflow, while the non-skin contacting surface is made hydrophilic to promote fluid transfer. This local differentiation resolves the contradiction by assigning appropriate properties to appropriate locations.
2Quantity of substance
If both layers of the surface sheet are made hydrophilic, then the surface sheet can absorb body fluid, but the liquid is retained in the surface sheet and backflow amount increases
Solution Approach 1:
The surface sheet is segmented into a water-repellent layer and a hydrophilic layer, where the water-repellent layer prevents backflow while the hydrophilic layer absorbs fluid. This segmentation resolves the contradiction by ensuring that not all layers have the same property.
Solution Approach 2:
Instead of making both layers hydrophilic as in conventional designs, the invention inverts the approach by making the skin-contacting layer water-repellent and the non-skin layer hydrophilic. This inversion allows the surface sheet to simultaneously prevent backflow and facilitate fluid transfer.
3Productivity
If the surface sheet uses a non-woven fabric with high permeability, then body fluid can be quickly transferred, but the anti-backflow property is compromised
Solution Approach 1:
The surface sheet is divided into a water-repellent layer with high permeability for quick fluid transfer and a hydrophilic layer for preventing backflow. Each layer is optimized for its specific function, allowing the system to achieve both high absorption rate and anti-backflow property.
Solution Approach 2:
The surface sheet uses a composite structure combining water-repellent non-woven fabric and hydrophilic non-woven fabric. This composite material approach allows the surface sheet to simultaneously achieve high permeability for rapid fluid transfer and anti-backflow property through the synergistic action of the two materials.
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 effectively transfers body fluids to the absorbent body while significantly reducing backflow, enhancing the absorbent article's performance by optimizing fluid absorption and retention.
Implementation Method 1
the upper layer non-woven fabric disposed on the skin side has hydrophilicity that easily absorbs body fluid
Implementation Method 2
the lower layer non-woven fabric disposed on the non-skin side is made water-repellent such that the body fluid once passed through is hardly absorbed
Data Source
AI summary
A liquid permeable surface sheet (3) includes an upper layer non-woven fabric (20) which is provided at the skin side, and which is hydrophilic, and a lower layer non-woven fabric (21) which is provided at the non-skin side, and which is water repellent. Multiple apertures (22) are formed which penetrate the upper layer non-woven fabric and the lower layer non-woven fabric. Accordingly, body fluid transfers smoothly through the apertures to an absorbent body. The upper layer non-woven fabric at the skin side is made to be hydrophilic such that body fluid readily permeates therethrough. The lower layer non-woven fabric at the non-skin side is made to be water repellent such that the body fluid which has passed through is not readily absorbed again. Accordingly, the backflow amount of body fluid can be reduced.