Modified Cellulose Nanofibers for Faster Drainage and Resin Dispersion

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Solution Overview

Problem

Cellulose nanofibers obtained by fibrillating plant fibers to the nanometer level are highly hydrophilic, leading to high viscosity and water retention, resulting in long drainage times during dehydration and aggregation upon drying, making uniform dispersion in resins difficult, especially in hydrophobic resins.

Innovation Solution

Neutralizing cationic cellulose nanofibers with an anionic additive to reduce drainage time, enhance dispersion, and increase the strength of the resulting resin composition.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of operation

If cellulose nanofibers are obtained by mechanical treatment in an aqueous medium, then the nanofibers are highly hydrophilic and have good dispersibility in water, but the viscosity and water retention become extremely high, resulting in long drainage time

Engineering Contradiction:
Improvedispersibility in waterVSAvoiddrainage time
Core Design Contradiction:
Ease of operationVSLoss of time

Solution Approach 1:

The patent changes the surface charge parameter of cellulose nanofibers from negative (natural state) to positive (by cationic modification), then neutralizes it by controlling the ratio of cationic to anionic components. This parameter change reduces water retention and drainage time while maintaining dispersibility.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent creates a composite structure by combining cationically modified cellulose nanofibers with anionic components in specific ratios. This composite approach allows the nanofibers to maintain water dispersibility while reducing excessive hydrophilicity that causes long drainage times.

Inventive Principle:
Principle #40Composite materials

2Productivity

If cellulose nanofibers are dehydrated and dried, then they can be recovered, but they aggregate due to hydrogen bonding, making it difficult to uniformly re-disperse

Engineering Contradiction:
Improverecovery efficiencyVSAvoiduniformity of dispersion
Core Design Contradiction:
ProductivityVSStability of the object's composition

Solution Approach 1:

The patent changes the surface charge parameter from negative to positive through cationic modification, which reduces hydrogen bonding between nanofibers. This prevents aggregation during drying and ensures uniform re-dispersion while maintaining recovery efficiency.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent applies preliminary anti-action by introducing cationic groups that counteract the natural tendency of cellulose nanofibers to aggregate through hydrogen bonding. This preliminary modification prevents aggregation before drying occurs, ensuring uniform dispersion upon recovery.

Inventive Principle:
Principle #9Preliminary anti-action

3Ease of manufacture

If highly hydrophilic cellulose nanofibers are compounded with highly hydrophobic resins, then resin composite materials can be formed, but the nanofibers do not disperse uniformly in the resin

Engineering Contradiction:
Improveresin composite formationVSAvoiduniformity of dispersion in resin
Core Design Contradiction:
Ease of manufactureVSStability of the object's composition

Solution Approach 1:

The patent changes the surface charge parameter of cellulose nanofibers from negative to positive, and then neutralizes it by controlling the cationic to anionic component ratio. This creates a surface property that is compatible with hydrophobic resins, enabling uniform dispersion while maintaining ease of composite formation.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent applies local quality by modifying only the surface properties of cellulose nanofibers through cationic modification and neutralization, while keeping the bulk cellulose structure intact. This localized surface modification improves resin compatibility without affecting the intrinsic properties needed for composite formation.

Inventive Principle:
Principle #3Local quality

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 modified cellulose nanofibers exhibit shortened drainage times, uniform dispersion in molding resins, and improved mechanical strength of the resin composition, facilitating their use in various applications.

Implementation Method 1

neutralizing cationic groups of cationic cellulose nanofibers with an anionic additive

Methodology Applied
Scientific EffectElectrostatic interaction: Electrostatics

Implementation Method 2

a network is formed by the cellulose nanofibers... due to hydrogen bonding between the nanofibers

Methodology Applied
Scientific EffectHydrogen bonding: Chemical Bonding

Data Source

PatentUS9074077B2Modified cellulose nanofibers, production method thereof, and resin composition using same
Publication Date: 2015.07.07 DIC CORP

AI summary

The present invention relates to modified cellulose nanofibers obtained by neutralizing cationic groups of cationic cellulose nanofibers with an anionic additives. Moreover, the present invention relates to a resin composition containing the aforementioned modified cellulose nanofibers and a molding resin, and to a molded body obtained by molding the resin composition. Furthermore, the present invention relates to a production method of modified cellulose nanofibers comprising neutralizing cationic groups of cationic cellulose nanofibers with an anionic additives.