High-Tenacity Cellulosic Microfiber Production via Hydraulic Drawing

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Solution Overview

Problem

Current methods for producing cellulosic microfibers with high tenacity and uniformity are economically and ecologically inefficient, and the fibers are not suitable for high-performance textile applications due to low strength and irregularity, limiting the production of fine yarns required for lightweight textiles.

Innovation Solution

Development of a high-tenacity cellulosic regenerated fiber with a titer of 0.6 to 0.9 dtex, achieving a tenacity of at least 1.3√T + 2T cN and a wet modulus of 0.5*√T cN with 5% elongation, suitable for high-performance spinning processes, and adaptable spinning parameters for staple fiber production.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Volume of moving object

If standard viscose fibers are used with small titer, then fiber fineness is improved, but fiber tenacity and wet strength deteriorate

Engineering Contradiction:
Improvefiber titerVSAvoidfiber tenacity
Core Design Contradiction:
Volume of moving objectVSStrength

Solution Approach 1:

The patent applies parameter changes by optimizing the spinning bath composition (using specific concentrations of sulfuric acid, sodium hydroxide, and zinc sulfate), controlling the spinning temperature (10-25°C), and adjusting the draw-off speed (0.5-2.0 m/min) to achieve both fine titer (0.9-16 dtex) and high tenacity (≥3.0 cN/tex) simultaneously

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent utilizes phase transitions in the viscose regeneration process, where the cellulose xanthogenate solution undergoes phase separation in the spinning bath to form solid fibers, and the controlled crystallization during drawing enhances fiber strength while maintaining fineness

Inventive Principle:
Principle #36Phase transitions

2Volume of moving object

If spray hole diameters are reduced to produce ultrafine fibers, then fiber fineness is improved, but spinning safety and fiber regularity deteriorate

Engineering Contradiction:
Improvefiber diameterVSAvoidspinning safety
Core Design Contradiction:
Volume of moving objectVSReliability

Solution Approach 1:

The patent introduces an intermediary substance (zinc sulfate at 5-20 g/L) in the spinning bath that acts as a leveling agent, preventing deposits on spray holes and ensuring stable jet flow, thereby maintaining spinning safety while producing uniform ultrafine fibers

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The patent applies preliminary action by pre-treating the spinning bath with zinc sulfate and controlling the pH level before spinning begins, which prevents deposit formation on spray holes during the spinning process and maintains consistent fiber quality

Inventive Principle:
Principle #10Preliminary action

3Volume of moving object

If hydraulic drawing is used instead of mechanical drawing, then fiber titer reduction is improved, but fiber tenacity deteriorates

Engineering Contradiction:
Improvefiber titerVSAvoidfiber tenacity
Core Design Contradiction:
Volume of moving objectVSStrength

Solution Approach 1:

The patent replaces mechanical drawing with hydraulic drawing using a water jet system, where the spinning jet itself provides the drawing force, eliminating the need for separate mechanical drawing equipment and achieving both fine titer and high tenacity through controlled hydrodynamic forces

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

4Volume of moving object

If fibers with small titer are produced without attention to tenacity, then fiber fineness is improved, but processing reliability in textile chain deteriorates

Engineering Contradiction:
Improvefiber titerVSAvoidprocessing reliability
Core Design Contradiction:
Volume of moving objectVSEase of manufacture

Solution Approach 1:

The patent applies preliminary action by pre-setting the spinning bath parameters (acid concentration,碱 concentration, zinc sulfate, temperature) and fiber properties (titer, tenacity, uniformity) before textile processing, ensuring that the fine fibers meet the minimum requirements for reliable processing in the textile chain

Inventive Principle:
Principle #10Preliminary action

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 high-tenacity fibers enable the production of fine, soft, and strong yarns suitable for high-quality textiles, exceeding previous spinning limits and allowing for trouble-free processing in modern spinning processes, with improved wear comfort and reduced production costs.

Implementation Method 1

the production of viscose microfibers... based on a cellulose xanthogenate solution

Methodology Applied
Scientific EffectPhase separation: Phase Change

Implementation Method 2

the production of viscose microfibers... based on a cellulose xanthogenate solution

Methodology Applied
Scientific EffectPrecipitation: Precipitation

Data Source

PatentUS11932969B2Microfiber
Publication Date: 2024.03.19 LENZING AG

AI summary

The present invention relates to a high-tenacity cellulosic regenerated fiber with an individual fiber titer of between 0.6 and 0.9 dtex and yarns and planar textile structures which contain regenerated fibers of this kind.