Technical Textile Recycling via Centrifugal Coating Separation

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Solution Overview

Problem

Current methods for recycling silicone-coated technical textiles, such as airbags, fail to achieve perfect separation of polyamide fibers from the silicone coating, leading to degraded mechanical properties and clogging issues during injection molding.

Innovation Solution

A process involving the micronization of textile residues into micrometric particles, followed by treatment in a medium with controlled density to separate the thermoplastic fibers from the coating using centrifugal decantation, allowing for the production of high-performance recycled thermoplastic formulations.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If chemical treatment processes are used to separate polyamide from silicone coating, then separation is achieved, but the process complexity and cost increase

Engineering Contradiction:
Improveseparation efficiencyVSAvoidprocess complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent replaces complex chemical treatment processes with a simple mechanical centrifugal separation system. The densimetric separation apparatus uses centrifugal force to separate polyamide fibers from silicone coating based on density differences, eliminating the need for chemical reagents and complex neutralization steps while achieving effective separation.

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

Solution Approach 2:

The patent changes the physical parameter of density utilization to achieve separation. By controlling the liquid medium density and using centrifugal acceleration, the system exploits the density difference between polyamide and silicone to achieve separation without chemical treatment, simplifying the overall process.

Inventive Principle:
Principle #35Parameter changes

2Ease of manufacture

If direct extrusion of coated airbag pieces is performed, then recycling is simplified, but mechanical properties of recycled articles deteriorate

Engineering Contradiction:
Improverecycling simplicityVSAvoidmechanical properties
Core Design Contradiction:
Ease of manufactureVSStrength

Solution Approach 1:

The patent extracts the silicone coating from the polyamide fibers through densimetric separation before extrusion. This pre-separation step removes the harmful coating material that would otherwise degrade the mechanical properties of recycled articles, while still maintaining a simplified process compared to chemical treatment methods.

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The patent performs preliminary separation of the coating from the fibers before the extrusion step. This preliminary action ensures that only clean polyamide fibers are extruded into granules, guaranteeing good mechanical properties in the final recycled articles while keeping the overall process simple and efficient.

Inventive Principle:
Principle #10Preliminary action

3Strength

If coating is present on technical textiles, then mechanical resistance is improved, but separation and reuse become difficult

Engineering Contradiction:
Improvemechanical resistanceVSAvoidseparation difficulty
Core Design Contradiction:
StrengthVSEase of manufacture

Solution Approach 1:

The patent exploits the density parameter difference between the coating and the fiber substrate to achieve separation. By adjusting the liquid medium density and applying centrifugal force, the system separates the coating from the fibers based on their different densities, providing an easy and effective separation method that preserves the integrity of both materials.

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

This process effectively separates the thermoplastic fibers from the silicone coating, resulting in granules with mechanical properties comparable to primary thermoplastic formulations, while minimizing energy and financial costs.

Implementation Method 1

separation by centrifugal force of the thermoplastic material of interest

Methodology Applied
Scientific EffectCentrifugal decantation: Centrifugal Separation

Implementation Method 2

suspending said mixture of particles in a medium allowing the separation of the coating particles and the thermoplastic fibrous particles; said medium having a density between the density of the thermoplastic fibrous particles and the density of the coating

Methodology Applied
Scientific EffectDensity gradient separation: Density Gradient

Data Source

PatentEP2691219B1Method for treating technical textiles
Publication Date: 2018.05.16 RHODIA OPERATIONS SAS

AI summary

The present invention relates to a method for treating technical textiles containing thermoplastic fibers and including a coating, such as inflatable airbags, in particular, which uses the principle of centrifugal decantation in order to separate the debris of the fibers and the coating material. The invention also relates to a method for manufacturing a thermoplastic composition, in particular for molding, which is produced using the resulting debris of the fibers and, optionally, reinforcing fillers. The specific feature of the present invention relates to the preparation of the coating-free fabric, thus resulting in formulations having high mechanical performance levels.