Nonwoven substrate and method for its manufacture

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Solution Overview

Problem

Conventional wipe substrates with synthetic fibers are not biodegradable and lack the convenient use characteristics of biodegradable alternatives.

Innovation Solution

A nonwoven substrate composed of a homogeneous mix of lyocell fibers, viscose fibers, and cellulosic man-made fibers with specific titers and cross-sections, processed through carding and high-pressure jet spinning to achieve enhanced tensile strength, lotion retention, and dispensing ease.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Object-affected harmful factors

If biodegradable fiber materials (viscose, lyocell) are used instead of synthetic fibers, then environmental biodegradability is improved, but tensile strength and dimensional stability deteriorate

Engineering Contradiction:
ImprovebiodegradabilityVSAvoidtensile strength
Core Design Contradiction:
Object-affected harmful factorsVSStrength

Solution Approach 1:

The patent creates a composite nonwoven substrate combining three different cellulosic fiber types (viscose, lyocell, and stiffening cross-section fibers) with specific titer ranges and length specifications. This composite structure allows the material to maintain biodegradability while achieving enhanced tensile strength (≥17 N/5cm in CD) and dimensional stability through the synergistic combination of fiber properties, where the stiffer fibers provide structural support to the more compliant biodegradable fibers.

Inventive Principle:
Principle #40Composite materials

Solution Approach 2:

The patent applies local quality by assigning different fiber types to specific functional roles within the substrate structure. The viscose and lyocell fibers provide softness and biodegradability, while the cellulosic fibers with stiffening cross-sections (round or multilobal) provide tensile strength and dimensional stability. This localized functional differentiation allows the overall material to achieve both biodegradability and mechanical performance.

Inventive Principle:
Principle #3Local quality

2Object-affected harmful factors

If biodegradable fiber materials are used instead of synthetic fibers, then environmental biodegradability is improved, but convenient use characteristics (dimensional stability, dispensing ease) deteriorate

Engineering Contradiction:
ImprovebiodegradabilityVSAvoiddispensing ease
Core Design Contradiction:
Object-affected harmful factorsVSEase of operation

Solution Approach 1:

The composite fiber blend with specific proportions (35-45% lyocell, 35-45% viscose, 15-25% stiffening cross-section fibers) creates a substrate that maintains its shape and dimensional stability during dispensing operations. The stiffening fibers provide the necessary structural rigidity to enable easy dispensing from packages, while the overall biodegradable composition preserves environmental benefits.

Inventive Principle:
Principle #40Composite materials

Solution Approach 2:

By incorporating fibers with stiffening cross-sections (round cross-section at >2 dtex or multilobal cross-section) into specific proportions, the patent locally enhances the dispensing characteristics of the substrate. These stiffer fibers provide the necessary mechanical properties for easy dispensing while the majority of the substrate remains composed of soft, biodegradable viscose and lyocell fibers.

Inventive Principle:
Principle #3Local quality

3Strength

If conventional viscose/polyester or viscose/polypropylene blends are used, then tensile strength is sufficient, but biodegradability and textile feel deteriorate

Engineering Contradiction:
Improvetensile strengthVSAvoidbiodegradability
Core Design Contradiction:
StrengthVSObject-affected harmful factors

Solution Approach 1:

The patent changes the fundamental parameter of fiber composition from synthetic polymer-based (polyester, polypropylene) to cellulosic-based (viscose, lyocell, and stiffening cross-section fibers). This parameter change transforms the material from non-biodegradable to biodegradable while maintaining adequate tensile strength through the selection of specific fiber properties including titer ranges (1.5-1.9 dtex for viscose and lyocell, 2.0+ dtex for stiffening fibers) and cross-section geometries.

Inventive Principle:
Principle #35Parameter changes

Data Source

PatentEP4127288B1Nonwoven substrate and method for its manufacture
Publication Date: 2024.07.31 LENZING AG
  • EP4127288B1 patent drawingFigure 1~2
  • EP4127288B1 patent drawingFigure 3
  • EP4127288B1 patent drawing

AI summary

This invention relates to a nonwoven substrate, containing lyocell fibers with a titer of between 1.5 and 1.9 dtex, viscose fibers with a titer of between 1.5 and 1.9 dtex and cellulosic man-made fibers with a stiffening cross-section. It further relates to a method of manufacturing such nonwovens as well as to their use and to wet wipes containing them.