Crosslinked Carboxyalkyl Cellulose Fibers for Absorbency Under Pressure
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Solution Overview
Problem
Personal care absorbent products face challenges with existing materials, such as cellulosic fibers and synthetic superabsorbent polymers, which either lack effective liquid retention under pressure or are non-biodegradable, leading to issues like skin wetness, leakage, and environmental concerns.
Innovation Solution
Development of substantially water-insoluble, water-swellable, carboxyalkyl cellulose fibers with non-permanent and permanent intra-fiber crosslinks, mimicking the properties of both cellulosic fibers and synthetic superabsorbents, offering enhanced liquid storage capacity and wicking ability while being biodegradable.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If cellulosic fibers are used in the fibrous matrix, then the matrix provides liquid wicking and pad strength, but the fibers can absorb only about 2-3 g/g of liquid within the cell walls and readily release acquired liquid on application of pressure
Solution Approach 1:
The patent applies parameter changes by chemically modifying cellulosic fibers through carboxyalkylation to introduce hydrophilic carboxyl groups, thereby increasing the fibers' liquid absorbent capacity from 2-3 g/g to significantly higher levels while maintaining the fibrous structure's wicking and strength properties
Solution Approach 2:
The patent creates composite materials by combining modified cellulosic fibers with superabsorbent polymer particles in the fibrous matrix, achieving synergistic effects where the composite structure provides both the liquid wicking and structural integrity of cellulosic fibers and the high liquid retention capacity of superabsorbent polymers under pressure
2Quantity of substance
If synthetic superabsorbent polymer particles are used to increase liquid absorbent capacity, then higher absorbency under pressure is achieved, but the core lacks liquid wicking and distribution capability and structural strength
Solution Approach 1:
The patent merges two different absorbent mechanisms by combining superabsorbent polymer particles with modified cellulosic fibers in a single fibrous matrix, allowing the superabsorbent particles to provide high capacity under pressure while the cellulosic fibers provide liquid wicking and distribution pathways
Solution Approach 2:
The fibrous matrix is designed to perform multiple functions simultaneously: the superabsorbent polymer particles provide high liquid retention under pressure, while the modified cellulosic fibers provide liquid wicking, distribution, and structural strength, creating a multi-functional absorbent core
3Object-generated harmful factors
If natural-based absorbent materials are used, then biodegradability is achieved, but the materials tend to form gels that limit liquid transport and distribution
Solution Approach 1:
The patent applies local quality by creating distinct regions within the fibrous matrix: superabsorbent polymer particles that form localized gel structures for high-capacity retention, and modified cellulosic fiber regions that maintain open porous structures for efficient liquid transport and distribution, allowing both gel formation and fluid flow to coexist in different locations
4Ease of manufacture
If fluff pulp fibers are used for their high fiber length and ease of processing, then processing efficiency is improved, but the fibers absorb only about 2-3 g/g of liquid within cell walls and release liquid on pressure application
Solution Approach 1:
The patent applies parameter changes by chemically modifying the physical and chemical parameters of fluff pulp fibers through carboxyalkylation, introducing carboxyl groups that dramatically increase the fibers' liquid absorbent capacity from 2-3 g/g to much higher levels while preserving the fibers' structural integrity and processing characteristics
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 new fibers provide improved absorbency and wicking properties, maintaining structural integrity under liquid insult, and are economically viable for use in personal care products, addressing the limitations of current materials by enhancing skin dryness and environmental sustainability.
Implementation Method 1
Superabsorbents are water-swellable, generally water-insoluble absorbent materials having a liquid absorbent capacity of at least about 10, preferably of about 20, and often up to about 100 times their weight in water
Implementation Method 2
water-swellable, generally water-insoluble absorbent materials
Implementation Method 3
treating the carboxyalkyl cellulose fibers with a multi-valent metal ion crosslinking agent and a second crosslinking agent to provide substantially water-insoluble, water-swellable, carboxyalkyl cellulose fibers
Implementation Method 4
the core's fibrous matrix provides the essential functions of liquid wicking
Data Source
AI summary
Methods for making substantially water-insoluble, water-swellable, non-regenerated, carboxyalkyl cellulose fibers, wherein the fibers have a surface having the appearance of the surface of a cellulose fiber, and wherein the fibers include a plurality of non-permanent intra-fiber metal crosslinks and a plurality of permanent intra-fiber crosslinks.