Elastic Fiber Separation Using Gamma-Valerolactone Solvent

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Solution Overview

Problem

Existing methods for separating elastic fibers from polymer blends, particularly those containing polyamide or cellulose-based polymers, are inefficient and often require hazardous solvents, making recycling of these materials difficult and environmentally harmful.

Innovation Solution

A method using gamma-valerolactone as a solvent to dissolve elastic fibers at temperatures below 170°C, allowing for the separation of polyamide or cellulose-based polymers from elastic fibers without harmful chemicals, enabling effective recovery and reuse of the polymers.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If hazardous solvents are used to separate elastic fibers from polymer blends, then the separation efficiency is improved, but the environmental harm and safety risks increase

Engineering Contradiction:

Improveseparation efficiencyVSAvoidenvironmental harm

Core Design Contradiction:

ProductivityVSObject-affected harmful factors

Solution Approach 1:

The patent converts the previously harmful approach of using hazardous solvents into a beneficial process by employing gamma-valerolactone, a solvent derived from renewable resources. This green solvent achieves effective separation of elastic fibers from polymer blends while eliminating the environmental and safety hazards associated with traditional solvents, thus converting a harmful practice into a beneficial sustainable process

Inventive Principle:

Principle #22Blessing in disguise (Convert harm into benefit)

Solution Approach 2:

The patent changes the chemical parameter of the solvent from hazardous conventional solvents to gamma-valerolactone, which has different solubility characteristics. This parameter change enables selective dissolution of elastic fibers while leaving polyamide or cellulose-based polymers intact, achieving effective separation without the harmful effects of traditional solvents

Inventive Principle:

Principle #35Parameter changes

2Device complexity

If thermal treatment is used to remove elastic fibers, then the separation process is simplified, but the polyamide or cellulose-based polymer may be damaged

Engineering Contradiction:

Improveprocess complexityVSAvoidpolymer integrity

Core Design Contradiction:

Device complexityVSReliability

Solution Approach 1:

The patent introduces gamma-valerolactone as an intermediary substance that mediates the separation process. Instead of directly applying thermal treatment that could damage the polymer, the solvent acts as a mediator to selectively dissolve elastic fibers at lower temperatures, protecting the polyamide or cellulose-based polymer from thermal degradation while still achieving effective separation

Inventive Principle:

Principle #24Intermediary (Mediator)

Solution Approach 2:

The patent replaces the mechanical/thermal approach (thermal treatment and washing) with a chemical dissolution approach using gamma-valerolactone. This substitution allows separation to occur through selective solubility differences rather than thermal degradation, maintaining polymer integrity while achieving the same separation objective

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

3Loss of substance

If dissolution methods are used to recover polymeric materials, then the recovery yield is improved, but the application range is limited to specific polymer types

Engineering Contradiction:

Improverecovery yieldVSAvoidapplication range

Core Design Contradiction:

Loss of substanceVSAdaptability or versatility

Solution Approach 1:

The patent demonstrates that gamma-valerolactone serves as a universal solvent for multiple types of elastic fibers (polyurethane, polyester, and their copolymers) when combined with polyamide or cellulose-based polymers. This multi-functionality allows the same dissolution method to be applied across different polymer blend compositions, significantly expanding the application range while maintaining high recovery yields

Inventive Principle:

Principle #6Universality (Multi-functionality)

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 method achieves high yields and purities in the recovery of polyamide or cellulose-based polymers by effectively removing elastic fibers, opening up opportunities for their re-use and reducing environmental impact.

Implementation Method 1

contacting the polymer blend with the solvent comprising gamma-valerolactone at a temperature T1 of below 170°C

Methodology Applied

Scientific EffectDissolution: Solvation

Data Source

PatentUS20260078232A1Separation of elastic fibers in textile materials

Publication Date: 2026.03.19 BASF SE

AI summary

Disclosed herein is a method for separating a polymer blend, where the polymer blend includes (i) a polyamide and/or a cellulose based polymer, (ii) an elastic fiber: the method including: (a) providing the polymer blend and providing a solvent including gamma-valerolactone; and (b) contacting the polymer blend with the solvent including gamma-valerolactone at a temperature T1 of <170° C., thereby obtaining a solvent, which is enriched in dissolved elastic fiber, and a residue of the polymer blend, which is depleted of said elastic fiber and includes the polyamide and/or the cellulose based polymer.Further disclosed herein is a polyamide and/or cellulose based polymer obtained from the method.Additionally disclosed herein are a method of using the cellulose based polymer and a method of using the polyamide polymer.