Microfibrillated Cellulose-Coated SAP for Thin Absorbent Articles
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Solution Overview
Problem
Existing disposable absorbent articles face challenges in maintaining absorbency and preventing superabsorbent polymer (SAP) migration within the absorbent core, leading to non-uniform absorbency and stiffness issues as the absorbent matrix is reduced to achieve thinner products.
Innovation Solution
The development of an absorbent composite comprising a nonwoven substrate with a microfibrillated cellulose-coated superabsorbent polymer layer, where the SAP is uniformly distributed within a carded fiber web, and a cover layer, using a hydro-entanglement process to join the components without binders, ensuring SAP immobilization and maintaining flexibility.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Length of stationary object
If the amount of absorbent matrix is reduced to decrease product thickness, then the thickness of the absorbent article is reduced, but the SAP migrates within the absorbent core causing non-uniform absorbency
Solution Approach 1:
The patent uses an absorbent matrix as an intermediary material that physically interacts with SAP particles through hydrogen bonding and mechanical entanglement. This intermediary prevents SAP migration while maintaining thin profile, resolving the contradiction between reduced thickness and uniform absorbency
Solution Approach 2:
The patent creates a composite absorbent core combining SAP particles with absorbent matrix materials (cellulose, wood pulp, or synthetic fibers). This composite structure provides both thickness reduction and SAP stabilization, simultaneously achieving thinner profile and uniform absorbency
2Reliability
If gluing is used to stabilize the SAP, then the SAP migration is prevented, but the absorbent core becomes uncomfortably stiff and loses swelling capacity
Solution Approach 1:
The patent employs a disposable absorbent matrix material that provides temporary stabilization during use without requiring permanent bonding. The matrix naturally restrains SAP particles through physical entanglement and hydrogen bonding, eliminating the need for gluing and maintaining flexibility
Solution Approach 2:
The patent changes the bonding mechanism from strong chemical bonds (gluing) to weaker physical interactions (hydrogen bonding and mechanical entanglement). This parameter change in bonding strength prevents SAP migration while preserving the flexibility and swelling capacity of the absorbent core
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
This solution maintains high absorbency while reducing product thickness, minimizing stiffness, and ensuring uniform absorbency by immobilizing SAP within the composite, enhancing the performance of disposable absorbent articles like diapers.
Implementation Method 1
The nonwoven substrate comprises a nonwoven support sheet, for example, a polypropylene spunbond (PPSB) nonwoven support sheet, attached to a carded fiber web through a hydro-entanglement process
Implementation Method 2
an absorbent layer, and a cover layer. The absorbent layer comprises microfibrillated cellulose-coated superabsorbent polymer
Implementation Method 3
The absorbent core is designed to contain and distribute fluid that passes through the topsheet. A typical absorbent core is made out of a high or super absorbent polymer (SAP) stabilized by an absorbent matrix
Implementation Method 4
SAP can be in the form of particles, fibers, foams, web, spheres, agglomerates of regular or irregular shapes, and film
Data Source
Figure 1A~1B
Figure 2
Figure 3
AI summary
A thin absorbent composite is provided wherein a nonwoven support sheet is hydro-entangled with a carded fiber web to provide a nonwoven substrate. The nonwoven substrate is coated with an absorbent layer comprising microfibrillated cellulose-coated superabsorbent polymer particles. A cover layer is placed above the absorbent layer to provide the absorbent composite. A process for manufacturing the absorbent composite and an absorbent article containing the absorbent composite are also provided.