Layered Absorbent Core Layout for Flexibility After Liquid Uptake
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Solution Overview
Problem
Conventional absorbent members in absorbent articles, such as diapers, are bulky and lack flexibility after liquid absorption, leading to discomfort for the wearer due to increased rigidity and poor liquid retention properties.
Innovation Solution
An absorbent member with a laminate structure comprising a first core containing 80% absorbent polymer and a second core with a low-rigidity portion, where the absorbent polymer is distributed unevenly to maintain flexibility and enhance liquid absorption.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If the absorbent member consists of a fiber stack of fiber materials, then cushioning properties are excellent, but the absorbent article is bulky and stiff
Solution Approach 1:
The patent changes the material composition parameters by using a fiber stack with 5-50 mass% hydrophilic synthetic fibers and 50-95 mass% natural fibers, creating a balance between cushioning and thinness. This parameter optimization allows the absorbent member to maintain adequate cushioning while reducing bulkiness compared to conventional all-natural fiber constructions.
2Quantity of substance
If the absorbent member absorbs and retains body fluids, then absorption capacity is improved, but the absorbent member swells and becomes stiffer
Solution Approach 1:
The patent employs a composite fiber structure combining hydrophilic synthetic fibers (for liquid wicking and absorption) with natural fibers (for cushioning and breathability). This composite approach enables the absorbent member to achieve sufficient absorption capacity while the natural fiber component maintains flexibility and reduces stiffness even after fluid retention.
Solution Approach 2:
The patent creates regional variations in fiber composition and absorbent polymer distribution within the absorbent member. By concentrating absorbent polymers in specific zones and varying fiber types in different regions, the structure achieves effective fluid absorption while maintaining localized flexibility and comfort zones that prevent overall stiffening.
3Volume of moving object
If the absorbent member is thinned, then bulkiness is reduced, but absorption capacity and liquid retentivity deteriorate
Solution Approach 1:
The patent optimizes the thickness and composition parameters of the fiber stack and absorbent polymer layer to achieve a thin yet high-performance absorbent member. By controlling fiber blend ratios, absorbent polymer content and distribution, and layer structure, the patent reduces thickness while compensating for absorption capacity through enhanced material efficiency and strategic polymer placement.
Solution Approach 2:
The use of composite fiber materials with different absorption characteristics allows the patent to achieve high absorption capacity in a thinner profile. The hydrophilic synthetic fibers provide rapid liquid uptake in a thin layer, while natural fibers contribute to fluid retention and comfort, enabling reduced thickness without sacrificing overall absorption performance.
4Stability of the object's composition
If absorbent polymer is evenly distributed, then absorption uniformity is improved, but flexibility deteriorates due to swelling
Solution Approach 1:
The patent implements non-uniform distribution of absorbent polymers within the fiber stack, concentrating them in specific regions rather than evenly throughout. This localized distribution strategy allows high absorption uniformity in the active zones where polymers are concentrated, while regions with fewer polymers or different fiber compositions maintain flexibility and prevent overall stiffening of the absorbent member.
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 absorbent member maintains flexibility and improves liquid absorption performance without significant rigidity increase after liquid absorption, enhancing wearer comfort and absorption efficiency.
Implementation Method 1
the absorbent member absorbs and retains the excretion
Implementation Method 2
the liquid permeable sheet and the liquid impermeable sheet
Data Source
Figure 1
Figure 2~4
Figure 5(a)~5(b)
AI summary
In an absorbent member (10), a first core (14) containing an absorbent polymer (20) is placed between a first sheet (11) and an intermediate sheet (13), a second core (15) containing an absorbent fiber and the absorbent polymer (20) is placed between the intermediate sheet (13) and a second sheet (12), a proportion of the absorbent polymer (20) in a forming material of the first core (14) is 80% by mass or more, a ratio of a mass of the absorbent polymer (20) contained in the first core (14) to a total mass of the forming material of the first core (14) is higher than a ratio of a mass of the absorbent polymer (20) contained in the second core (15) to a total mass of a forming material of the second core (15), a basis weight of the absorbent polymer (20) in the first core (14) is smaller than a basis weight of the absorbent polymer (20) in the second core (15), and in a case where BR represents a flexural rigidity variation rate of a laminate structure consisting of the first sheet (11), the first core (14), and the intermediate sheet (13) per thickness variation before and after liquid absorption, the flexural rigidity variation rate being calculated by the following Formula (1), BR in each of two directions randomly selected from three directions consisting of two directions that are orthogonal to each other and another direction that intersects with the two directions without being orthogonal to the two directions is 5.0 or less. BR=Bw/Bd/T0c