Crosslinked Fibrous Blend for Absorbency Without Gel Blocking

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Solution Overview

Problem

Current personal care absorbent products, such as diapers and incontinent pads, face inefficiencies due to the use of non-biodegradable and costly acrylic acid-based superabsorbent polymers, which result in 'over-design' and gel blocking issues, leading to skin wetness and leakage.

Innovation Solution

A fibrous blend of mixed polymer fibers, comprising carboxyalkyl cellulose and galactomannan or glucomannan polymers, is developed, which is biodegradable, inexpensive, and reduces gel blocking by incorporating cellulose fibers, enhancing liquid wicking and retention capabilities.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Quantity of substance

If acrylic acid-based superabsorbent polymers are used to achieve high absorbency, then the absorbent capacity is improved, but the cost increases and environmental biodegradability deteriorates

Engineering Contradiction:

Improveabsorbent capacityVSAvoidcost

Core Design Contradiction:

Quantity of substanceVSEase of manufacture

Solution Approach 1:

The patent changes the chemical composition parameters by using carboxymethyl cellulose (a cellulose derivative) instead of acrylic acid-based polymers. This substitution maintains the superabsorbent properties while using a biodegradable, renewable resource that is less expensive and environmentally friendly, directly resolving the contradiction between absorbent capacity and cost/environmental factors

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The invention employs carboxymethyl cellulose-based superabsorbent fibers that are biodegradable and can be disposed of without long-term environmental persistence. This approach uses a cheaper, renewable material that degrades naturally, addressing both the cost reduction and environmental concerns associated with traditional acrylic acid-based SAPs

Inventive Principle:

Principle #27Cheap short-living objects (Disposable)

2Strength

If acrylic acid-based superabsorbent polymers are used to achieve high gel strength, then the absorbency under load is improved, but the interstitial liquid increases causing skin wetness

Engineering Contradiction:

Improvegel strengthVSAvoidskin wetness

Core Design Contradiction:

StrengthVSObject-affected harmful factors

Solution Approach 1:

The patent modifies the gel strength parameters by using carboxymethyl cellulose with specific degree of substitution and molecular weight characteristics. This creates a gel structure that maintains adequate absorbency under load while having lower interstitial liquid content, thereby reducing skin wetness and improving comfort

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The invention creates a composite fibrous structure combining carboxymethyl cellulose superabsorbent fibers with other cellulose fibers. This composite approach optimizes the gel strength to balance absorbency under load with reduced interstitial liquid, solving the contradiction between gel strength and skin wetness

Inventive Principle:

Principle #40Composite materials

3Quantity of substance

If superabsorbent fibers are used to achieve uniform liquid acquisition, then the absorbency uniformity is improved, but gel blocking occurs preventing liquid wicking

Engineering Contradiction:

Improveliquid acquisition uniformityVSAvoidgel blocking

Core Design Contradiction:

Quantity of substanceVSObject-generated harmful factors

Solution Approach 1:

The patent applies local quality by creating a fibrous structure where carboxymethyl cellulose superabsorbent fibers are distributed among other cellulose fibers. This local distribution prevents continuous gel formation that would cause blocking, while maintaining uniform liquid acquisition across the absorbent structure

Inventive Principle:

Principle #3Local quality

Solution Approach 2:

The invention uses a composite of carboxymethyl cellulose superabsorbent fibers with other cellulose fibers to prevent gel blocking. The composite structure allows liquid to wick through the non-gelling cellulose fibers while the superabsorbent fibers provide uniform liquid acquisition, resolving the contradiction between uniform absorbency and gel blocking

Inventive Principle:

Principle #40Composite materials

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 fibrous blend offers improved absorbency, reduced gel blocking, and efficient liquid management, making it suitable for personal care products while being environmentally friendly and cost-effective.

Implementation Method 1

The mixed polymer fiber is water insoluble and water-swellable and comprises a carboxyalkyl cellulose and a galactomannan polymer or a glucomannan polymer

Methodology Applied

Scientific EffectAbsorption: Absorption (physical)

Implementation Method 2

The mixed polymer fiber is formed by intermolecular crosslinking of mixed polymer molecules

Methodology Applied

Scientific EffectCrosslinking: Chemical Bonding

Implementation Method 3

incorporating cellulose fibers, enhancing liquid wicking and retention capabilities

Methodology Applied

Scientific EffectCapillary action: Capillary Action

Data Source

PatentUS7591891B2Fibrous blend and methods of preparation

Publication Date: 2009.09.22 GCF US HOLDINGS LLC

AI summary

A method for making crosslinked fibers containing cellulose fibers in which an aqueous solution comprising a carboxyalkyl cellulose and a galactomannan polymer or a glucomannan polymer in water is treated with a first crosslinking agent to provide a gel; the gel mixed with a water-miscible solvent to provide mixed polymer fibers; cellulose fibers are added to the mixed polymer fibers; and these fibers are treated with a second crosslinking agent to provide crosslinked fibers.