Nonwoven Sheet With Protrusions For Viscous Fluid Permeability
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Solution Overview
Problem
Existing non-woven fabric sheets for absorbent articles face challenges in effectively managing highly viscous liquids, such as soft stool, due to increased contact area with absorbent bodies, leading to reduced permeability and risk of skin soiling, and diffusion control mechanisms that can result in skin soiling over wide areas.
Innovation Solution
A non-woven fabric sheet with continuous surface irregularities featuring openings at intermediate heights of projections and a space below them, allowing for increased permeability of highly viscous liquids and reduced skin contact, formed through a manufacturing process involving carding, patterned airflow resistance, and heat fusion.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Area of stationary object
If the bottoms of grooves are made flat and openings are formed in the bottom portions, then the contact area with absorbent body increases, but highly viscous liquid permeability decreases
Solution Approach 1:
The invention transitions from a two-dimensional flat bottom surface to a three-dimensional structure by forming protrusions that extend upward from the groove bottoms. This dimensional change creates multiple levels (bottom surface and protrusion surfaces) that collectively provide both contact area and permeability pathways, resolving the contradiction between contact area and liquid permeability.
Solution Approach 2:
The protrusions formed in the groove bottoms create a porous-like structure with multiple surfaces and potential void spaces. This porous structure allows highly viscous liquids to permeate through the material while maintaining sufficient contact area with the absorbent body, addressing both requirements simultaneously.
2Ease of operation
If ridges are formed to control liquid diffusion direction, then diffusion direction is controlled, but skin soiling area increases
Solution Approach 1:
The invention applies different structural characteristics to different locations: the groove bottoms have protrusions for absorption and permeability, while the ridge structures provide diffusion control. This local differentiation allows each region to perform its specific function optimally without causing skin soiling, as the protrusions capture liquid before it can diffuse widely across the skin surface.
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 enhances the permeability of highly viscous liquids, reduces the diffusion area on the skin, and minimizes re-adherence, effectively managing liquids like newborn infant stool.
Implementation Method 1
a) a step for opening a fiber assembly to form a web by passing through a carding machine
Implementation Method 2
b) a step for placing the web obtained in step a) on a pattern plate, on which convex portions having a comparatively large air flow resistance and concave portions having a comparatively small air flow resistance are arranged in a regular pattern
Implementation Method 3
c) a step for heating the web and fusing at sites where fibers are mutually intersecting
Data Source
Figure 1
Figure 2~3
Figure 4~5
AI summary
Disclosed is a nonwoven sheet for use in absorbent articles such as disposable diapers which is capable of reducing the range of surface diffusion of, and reducing re-adhesion to the skin of, highly viscous fluid excretion. The disclosed nonwoven sheet has mutually perpendicular longitudinal, transverse and thickness directions, and has in the aforementioned thickness direction a front surface and a back surface opposite thereof. Ridges and grooves are formed alternately so as to extend in parallel in the aforementioned longitudinal direction and so as to form repeated undulations in the aforementioned transverse direction. The nonwoven sheet has a bottom surface which, when the aforementioned nonwoven sheet is placed on a horizontal surface with the back surface (opposite of the front surface in contact with the skin of the wearer) down, is the surface that contacts the aforementioned horizontal surface. On the back surface of the aforementioned grooves are formed in the aforementioned longitudinal direction alternately areas where the height from the bottom surface is relatively high and parts corresponding to the bottom surface. Openings are formed at least in the areas where the height from the bottom surface is relatively high, and a space is provided below said openings.