Flat Lyocell Nonwoven Composition for Stronger Consistent Sheets

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Solution Overview

Problem

The production of strong nonwoven materials, such as specialty papers, is hindered by the high cost and variability of natural fibers like abaca, which makes it difficult to reproduce consistent quality parameters.

Innovation Solution

Using flat, unfibrillated lyocell fibers with a cross-sectional aspect ratio of at least 1.8, preferably 4 or 6, in nonwoven materials, eliminating the need for natural strengthening fibers and reducing the need for energy-intensive fibrillation processes.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Strength

If natural plant fibers like abaca are used to increase tensile strength and ball-burst strength, then the strength of nonwoven materials is improved, but the cost increases and quality parameters become difficult to reproduce

Engineering Contradiction:
Improvetensile strengthVSAvoidreproducibility of quality parameters
Core Design Contradiction:
StrengthVSReliability

Solution Approach 1:

The patent changes the geometric parameters of lyocell fibers by creating a flat cross-section with high aspect ratio (at least 1.8, preferably at least 4 or 6) instead of conventional round cross-sections. This parameter change enables the fibers to interlock and entangle more effectively, achieving superior tensile strength and reproducibility without relying on variable natural fibers like abaca.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent creates a composite fiber system by combining flat lyocell fibers with natural plant-based fibers in specific weight ratios (5-70% flat lyocell, 30-95% natural fibers). This composite approach allows the flat lyocell fibers to provide structural strength and reproducibility while the natural fibers contribute to bulk and absorption properties, achieving both strength improvement and quality consistency.

Inventive Principle:
Principle #40Composite materials

2Strength

If abaca pulp is used to strengthen nonwoven materials, then tensile strength and ball-burst strength increase, but production cost increases

Engineering Contradiction:
Improveball-burst strengthVSAvoidproduction cost
Core Design Contradiction:
StrengthVSQuantity of substance

Solution Approach 1:

The patent replaces expensive abaca pulp with more cost-effective flat lyocell fibers that can be produced consistently through controlled manufacturing processes. The flat cross-section geometry provides enhanced strength properties at lower cost, making the nonwoven material more economically viable while maintaining or improving performance.

Inventive Principle:
Principle #27Cheap short-living objects (Disposable)

Solution Approach 2:

By changing the fiber cross-section from round to flat with high aspect ratio, the patent achieves superior ball-burst strength without requiring expensive natural fibers. The geometric modification enables better fiber-to-fiber contact and load distribution, providing cost-effective strength enhancement.

Inventive Principle:
Principle #35Parameter changes

3Strength

If seasonal natural fibers are used, then strength can be increased, but quality parameters vary strongly from season to season

Engineering Contradiction:
Improvefiber strengthVSAvoidquality consistency
Core Design Contradiction:
StrengthVSStability of the object's composition

Solution Approach 1:

The patent transforms the fiber geometry to a flat cross-section with controlled aspect ratio, creating a consistent structural parameter that can be reliably reproduced regardless of seasonal variations. This geometric standardization ensures uniform mechanical properties and quality parameters across different production batches and time periods.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The flat lyocell fibers inherently provide the strength and structural integrity functions previously requiring variable natural fibers. The self-consistent geometric structure of the flat fibers ensures reliable performance without depending on external natural fiber variations, achieving quality stability through intrinsic fiber properties.

Inventive Principle:
Principle #25Self-service

4Strength

If fibrillation processing is applied to natural fibers to improve strength, then tensile strength increases, but energy consumption and resource usage increase

Engineering Contradiction:
Improvetensile strengthVSAvoidenergy consumption
Core Design Contradiction:
StrengthVSUse of energy by moving object

Solution Approach 1:

The patent performs preliminary action by creating the flat cross-section geometry during fiber production before the nonwoven forming process. This pre-formed geometric structure enables enhanced strength without requiring subsequent energy-intensive fibrillation processing, as the flat shape itself provides improved interlocking and load distribution capabilities.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The patent extracts the fibrillation processing step from the production sequence by achieving the desired fiber morphology through the flat cross-section design itself. This eliminates the need for separate mechanical or chemical fibrillation treatments, reducing energy consumption and resource usage while maintaining strength enhancement.

Inventive Principle:
Principle #2Taking out (Extraction)

Data Source

PatentEP4660361A1Nonwoven material
Publication Date: 2025.12.10 LENZING AG
  • EP4660361A1 patent drawingFigure 1~2
  • EP4660361A1 patent drawingFigure 3~5
  • EP4660361A1 patent drawing

AI summary

The invention pertains to a nonwoven material and a method for the production of a nonwoven material. The method comprises at least the steps of suspending fibers in a liquid or gaseous suspension fluid and laying-down the fibers to form the nonwoven material. The nonwoven material comprises from 30 % to 95 % per weight natural plant-based fibers and/or man-made cellulosic fibers and from 5 % per weight to 70 % per weight of flat lyocell fibers. The flat lyocell fibers are provided with a flat cross section with a cross-sectional aspect ratio of at least 1.8. The surface of the flat lyocell fibers is free of fibrillation grooves.