Lyocell-Reinforced Textile Support for Fracture-Free Bituminous Membranes

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Solution Overview

Problem

Existing textile supports for bituminous membranes, primarily using glass reinforcement yarns, are prone to fractures during the manufacturing process and subsequent thermal stress, leading to structural failures and economic losses due to the fragility of glass fibers and limited mechanical property enhancement.

Innovation Solution

A textile support composed of a non-woven web of synthetic fibers with continuous high modulus reinforcement yarns made of cellulose-derived Lyocell fibers, which are mechanically needled or water-entangled and stabilized with a thermal treatment and chemical binder, offering improved mechanical and thermal stability without the drawbacks of glass fibers.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Strength

If glass reinforcement yarns are used, then high elastic modulus and low cost are achieved, but the yarns are subject to break during coupling and needling process

Engineering Contradiction:
Improveelastic modulusVSAvoidyarn fracture resistance
Core Design Contradiction:
StrengthVSReliability

Solution Approach 1:

The patent changes the material parameter from glass to cellulosic fiber, transforming the reinforcement yarn material to achieve both high elastic modulus and fracture resistance. The cellulosic fiber maintains the necessary mechanical properties while eliminating the brittleness and fracture issues inherent in glass yarns during processing.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent creates a composite textile support by combining non-woven synthetic fiber substrate with continuous cellulosic fiber reinforcement yarns. This composite structure integrates the flexibility and processing advantages of synthetic fibers with the high modulus and strength of cellulosic fibers, resolving the contradiction between strength and reliability.

Inventive Principle:
Principle #40Composite materials

2Strength

If glass reinforcement yarns are used, then high elastic modulus is achieved, but the reinforcement yarns do not increase the mechanical properties of the support in the longitudinal sense

Engineering Contradiction:
Improveelastic modulusVSAvoidlongitudinal mechanical properties
Core Design Contradiction:
StrengthVSForce

Solution Approach 1:

The patent changes the material composition from glass to cellulosic fiber, which has superior elongation at break properties. This parameter change enables the reinforcement yarns to effectively increase longitudinal mechanical properties while maintaining high elastic modulus, as cellulosic fibers can stretch and absorb energy before breaking.

Inventive Principle:
Principle #35Parameter changes

3Ease of manufacture

If mechanical needling is used to join textile substrates and reinforcement yarns, then consolidation is achieved, but glass yarns are subject to break during the needling process

Engineering Contradiction:
Improveconsolidation methodVSAvoidyarn fracture resistance
Core Design Contradiction:
Ease of manufactureVSReliability

Solution Approach 1:

The patent changes the reinforcement yarn material from brittle glass to more ductile cellulosic fiber, which can withstand the mechanical needling process without fracturing. This material parameter change allows the use of mechanical needling for consolidation while maintaining yarn integrity throughout the manufacturing process.

Inventive Principle:
Principle #35Parameter changes

4Stability of the object's composition

If glass reinforcement yarns are used, then dimensional stability is achieved, but the supports are subjected to structural failure during bitumen impregnation process

Engineering Contradiction:
Improvedimensional stabilityVSAvoidstructural integrity during impregnation
Core Design Contradiction:
Stability of the object's compositionVSStrength

Solution Approach 1:

The patent creates a composite structure combining non-woven synthetic fiber substrate with cellulosic fiber reinforcement yarns. This composite provides both dimensional stability from the rigid cellulosic fibers and structural integrity during bitumen impregnation from the flexible synthetic fiber matrix, preventing structural failure while maintaining shape.

Inventive Principle:
Principle #40Composite materials

Solution Approach 2:

The patent changes the reinforcement material to cellulosic fiber, which has better elongation properties than glass. This allows the support to maintain dimensional stability while accommodating the stresses and deformations occurring during bitumen impregnation without structural failure.

Inventive Principle:
Principle #35Parameter changes

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 use of Lyocell fibers provides a fracture-free support with enhanced mechanical and thermal strength, dimensional stability, and reduced weight, resulting in improved performance and cost-effectiveness compared to glass-reinforced supports.

Implementation Method 1

The textile substrates and the reinforcement yarns are joined by means of mechanical needling or water entangling

Methodology Applied
Scientific EffectMechanical needling:

Implementation Method 2

The textile substrates and the reinforcement yarns are joined by means of mechanical needling or water entangling

Methodology Applied
Scientific EffectWater entangling:

Implementation Method 3

The textile substrates and the reinforcement yarns are joined by means of mechanical needling or water entangling and consolidated using a chemical binder

Methodology Applied
Scientific EffectChemical adhesion: Adhesive

Implementation Method 4

consolidation occurs thermally by melting a low-melting component added to the substrate in the form of fibers or filaments

Methodology Applied
Scientific EffectMelting: Melting

Data Source

PatentEP2640883B1Reinforced textile support with cellulosic fiber multi-filaments, particularly for bituminous membranes
Publication Date: 2015.03.04 POLITEX S DI FREUDENBERG POLITEX
  • EP2640883B1 patent drawingFigure 1
  • EP2640883B1 patent drawingFigure 2
  • EP2640883B1 patent drawingFigure 3

AI summary

A reinforced textile support, particularly for bituminous membranes, made of at least one layer of polyester non woven web and continuous high modulus reinforcement yarns longitudinally set with respect to said layer. The reinforcement yarns consist of cellulosic fibre multi-filaments of the Lyocell type. The assembly is bound by mechanical needling or water entangling, stabilised by means of thermal treatment at a temperature of 200-250 °C and consolidated by means of a chemical binder.