Flexible Liquid Absorbing Structure Using Hot Melt Adhesive
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Solution Overview
Problem
Conventional sanitary absorbent articles are thick, leading to user discomfort and poor fit due to stiffness and potential loss of absorbency under compressive loads, with particulate superabsorbents often migrating or falling out, causing discomfort and staining.
Innovation Solution
A thin, flexible aqueous liquid absorbing structure comprising a homogeneous mixture of hot melt adhesive and aqueous liquid absorbing polymer, with the polymer present in amounts greater than 1% by weight, providing absorbency greater than 5 g/g and Gurley stiffness less than 400 mg, ensuring the absorbent material remains effective and anchored within the structure.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If conventional cellulosic fiber absorbent structures are used to provide requisite absorbency, then absorbency is improved, but thickness increases leading to user discomfort and poor fit
Solution Approach 1:
The patent changes the material composition parameters by incorporating superabsorbent polymers (sodium polyacrylate) in specific quantities (5-50 parts by weight per 100 parts cellulosic fiber) to achieve high absorbency in thin structures. This parameter change enables the absorbent structure to maintain compressive strength while reducing thickness from conventional >5mm to optimized ranges.
Solution Approach 2:
The patent creates a composite absorbent structure combining cellulosic fibers with superabsorbent polymer particles. This composite material leverages the high absorbency of superabsorbents and the structural integrity of cellulosic fibers, achieving both high absorbency and thin profile with improved fit and comfort.
2Quantity of substance
If thick absorbent structures are used to provide sufficient absorbency, then absorbency is improved, but flexibility deteriorates causing the article to deform or bunch in use
Solution Approach 1:
The patent optimizes the ratio of superabsorbent polymer to cellulosic fiber and controls the caliper (thickness) of the absorbent structure to maintain flexibility. By adjusting these parameters, the structure achieves high absorbency while remaining thin and conformable to body contours, preventing deformation and bunching during use.
3Quantity of substance
If compressive load is applied to thick absorbent structures, then absorbency is maintained, but liquid is expressed from the structure causing rewetting
Solution Approach 1:
The composite structure of superabsorbent polymer particles within a cellulosic fiber matrix provides both high absorbency and excellent liquid retention under compressive loads. The superabsorbents maintain their gel structure and retain liquid even when compressed, preventing rewetting of the wearer.
4Quantity of substance
If particulate superabsorbent is used in the absorbent structure, then absorbency per unit volume is improved, but particle migration or falling out occurs causing discomfort and staining
Solution Approach 1:
The patent creates a composite where superabsorbent polymer particles are embedded within a cellulosic fiber matrix. This composite structure physically entraps the particles, preventing migration and falling out while maintaining high absorbency per unit volume. The fiber network provides structural support that secures the superabsorbent particles in place.
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 results in a thin, flexible, and highly absorbent structure that maintains effectiveness under compressive loads, reducing user discomfort and preventing staining, while ensuring the absorbent material remains securely anchored and effective.
Implementation Method 1
an aqueous liquid absorbing polymer... provide an absorbency greater than 5 grams per gram (g/g)
Implementation Method 2
a homogeneous mixture of a hot melt adhesive and an aqueous liquid absorbing polymer
Data Source
AI summary
A thin, flexible absorbent structure comprising a flexible substrate and an aqueous liquid absorbing material disposed on said substrate, wherein said aqueous liquid absorbing material comprises a homogeneous mixture of a hot melt adhesive and an aqueous liquid absorbing polymer, wherein the aqueous liquid absorbing polymer is present in the mixture in an amount greater than 1% by weight of the mixture and the aqueous liquid absorbing structure has an absorbency greater than about 5 g/g, and a Gurley Stiffness less than about 400 mg and a caliper less than about 4 mm.