Cotton Fiber Front-Surface Sheet for Absorbent Articles
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Solution Overview
Problem
Conventional absorbent articles with cotton fiber front-surface sheets face issues of liquid retentiveness leading to sticky feelings and irritation, and when superabsorbent polymer content is excessive, initial absorption speed is slow, causing rebound and diffusion issues.
Innovation Solution
An absorbent article with a spunlace nonwoven cotton fiber front-surface sheet coated with a water repellent agent and featuring specific structural openings, combined with an absorber made of pulp fiber and superabsorbent polymer at predetermined basis weights and ratios, to enhance absorption speed and reduce diffusion.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If regular degreased cotton fiber is contained in the front-surface sheet, then the front-surface sheet has high liquid permeability, but the front-surface sheet itself has high liquid retentiveness and is likely to leave a sticky feeling on a surface
Solution Approach 1:
The patent applies different treatments to different parts of the cotton fiber structure. The surface region is treated to be water-repellent while the internal structure maintains high permeability. This is achieved through specific fiber processing that creates a gradient of properties from surface to interior, allowing liquid to pass through quickly while preventing retention on the surface.
Solution Approach 2:
The patent modifies the physical and chemical parameters of cotton fiber by controlling the degree of degreasing and applying specific surface treatments. By adjusting parameters such as fiber surface energy, hydrophobicity, and pore structure dimensions, the material achieves both high permeability and low surface retentiveness simultaneously.
2Object-affected harmful factors
If cotton fiber is used in the front-surface sheet, then a soft feeling on the skin like underwear can be realized, but when a large volume of body fluid is excreted, the body fluid remains in the front-surface sheet causing a moist feeling or irritation
Solution Approach 1:
The front-surface sheet is designed with spatially varying properties: the surface layer maintains cotton's natural softness and skin-friendliness, while the bulk structure provides rapid transport pathways for large volumes of fluid. This local differentiation allows the material to be gentle on skin during normal wear while efficiently handling incontinence events.
Solution Approach 2:
The patent creates a composite structure within the cotton fiber assembly, combining regions with different functional properties. The composite includes surface regions optimized for skin contact comfort and internal regions optimized for rapid fluid transport and distribution to the absorbent core, achieving both comfort and performance.
3Object-generated harmful factors
If the water absorbency of the skin-contact surface is made low to prevent sticky feeling, then residual liquid on surface is improved, but a liquid part of the excreted matter cannot easily permeate through the top sheet causing lateral leakage
Solution Approach 1:
The front-surface sheet is segmented into functionally distinct zones: surface regions with water-repellent properties to prevent sticking, and internal pathways with high permeability to enable rapid liquid transport. This segmentation allows contradictory requirements to be satisfied in different spatial locations within the same material structure.
Solution Approach 2:
The patent introduces an intermediary mechanism in the form of hydrophobic surface treatments on cotton fibers that mediate between liquid contact and liquid retention. This intermediary layer repels liquid at the surface while allowing it to pass through to the absorbent core, preventing both sticking and lateral leakage.
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 prevents rebounding, improves absorption speed, and minimizes urine diffusion on the front-surface sheet, maintaining a dry feeling and reducing skin irritation.
Implementation Method 1
the front-surface sheet is coated with a water repellent agent
Implementation Method 2
an absorber made of pulp fiber and superabsorbent polymer
Implementation Method 3
the absorber is made of a pulp fiber and a superabsorbent polymer
Data Source
Figure 1
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AI summary
[Problem] To prevent backflow, improve absorption speed, and reduce the diffusion of urine in a surface sheet in an absorbent article that uses cotton fibers in the surface sheet. [Solution] A medium or higher volume incontinence pad (1) that absorbs at least 20 cc of urine. A surface sheet (3), which is formed by coating a spun-lace non-woven cloth that is 100 weight% cotton fibers with a water repellent, has a plurality of openings (10) that pass from top to bottom formed in at least a region thereof that includes an excretion-orifice-facing section. An absorption body comprises a highly water-absorbent polymer and pulp fibers that do not include synthetic fibers. The basis weight of the highly water-absorbent polymer is 85-185 g/m2, the basis weight of the pulp fibers is 75-300 g/m2, and the ratio of the pulp fibers to the highly water-absorbent polymer is 70-30 weight%:30-70 weight%.