Polyurethane Elastic Yarn Light Resistance

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Solution Overview

Problem

Polyurethane elastic yarns degrade and become brittle due to light exposure, leading to reduced strength and elongation characteristics, and the addition of ultraviolet light absorbents in existing methods often compromises these properties further.

Innovation Solution

Incorporating specific ultraviolet light absorbents such as benzotriazole-based and benzophenone-based compounds with unsaturated bonds, alkoxy groups, or sulfonic acid groups into the polyurethane elastic yarns to enhance their light resistance and maintain strength and elongation characteristics.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If ultraviolet light absorbents are added to polyurethane elastic yarn to prevent light degradation, then light resistance is improved, but fracture strength and elongation characteristics deteriorate

Engineering Contradiction:

Improvelight resistanceVSAvoidfracture strength

Core Design Contradiction:

ReliabilityVSStrength

Solution Approach 1:

The patent changes the chemical parameters of the ultraviolet light absorbent by specifying particular molecular structures (benzotriazole with unsaturated bonds, benzophenone with sulfonic acid groups, or copolymers with benzotriazole/benzophenone skeletons). These parameter changes in the absorbent's chemical structure allow it to provide light resistance while maintaining compatibility with the polyurethane matrix, thus preserving fracture strength and elongation characteristics.

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The patent creates a composite material system where specifically selected ultraviolet light absorbents are integrated into the polyurethane elastic yarn matrix. The composite structure allows the absorbent molecules to be distributed within the polymer matrix, providing light resistance functionality while the polyurethane matrix maintains the mechanical strength and elasticity properties.

Inventive Principle:

Principle #40Composite materials

2Reliability

If ultraviolet light absorbents are added to polyurethane elastic yarn, then light resistance is improved, but recovery characteristics deteriorate

Engineering Contradiction:

Improvelight resistanceVSAvoidrecovery characteristics

Core Design Contradiction:

ReliabilityVSStability of the object's composition

Solution Approach 1:

The patent specifies precise chemical parameters of the ultraviolet light absorbent (benzotriazole with unsaturated bonds, benzophenone with sulfonic acid groups, or their copolymers) to ensure that the absorbent does not interfere with the polyurethane's phase separation structure and microhard segment formation, which are critical for recovery characteristics. The parameter changes in absorbent selection enable light resistance without compromising elastic recovery.

Inventive Principle:

Principle #35Parameter changes

3Reliability

If conventional ultraviolet light absorbents are used, then light resistance is achieved, but loss of absorbents during processing and washing increases

Engineering Contradiction:

Improvelight resistanceVSAvoidloss of ultraviolet light absorbent

Core Design Contradiction:

ReliabilityVSLoss of substance

Solution Approach 1:

The patent extracts the problematic conventional ultraviolet light absorbents and replaces them with specifically selected absorbents that have improved binding affinity to the polyurethane matrix. The selected absorbents (benzotriazole with unsaturated bonds, benzophenone with sulfonic acid groups, or their copolymers) are chemically more compatible with polyurethane, reducing their tendency to migrate and be lost during processing and washing while maintaining light resistance.

Inventive Principle:

Principle #2Taking out (Extraction)

Solution Approach 2:

The patent uses the polyurethane matrix itself as an intermediary that binds the ultraviolet light absorbent molecules. The selected absorbents have chemical structures that interact favorably with the polyurethane chains, creating a stable association that prevents absorbent loss during high-level processing and washing, while the polyurethane matrix transfers the light protection function to the yarn.

Inventive Principle:

Principle #24Intermediary (Mediator)

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 solution results in polyurethane elastic yarns with improved strength, elongation, and recovery characteristics, while minimizing the loss of ultraviolet light absorbents during processing and washing, allowing for better performance in actual use and maintaining excellent light resistance.

Implementation Method 1

there is known art for producing polyurethane elastic fiber by spinning a spinning starting solution containing polyurethane supplemented with various ultraviolet light absorbents

Methodology Applied

Scientific EffectUltraviolet light absorption: Absorption (EM radiation)

Data Source

PatentUS9404199B2Polyurethane elastic yarn and method for producing same

Publication Date: 2016.08.02 TORAY OPELONTEX CO LTD

AI summary

ProblemTo provide a polyurethane elastic yarn with excellent elongation, recoverability, and light resistance that is suitable for use in stretchable fabrics and clothing, and to provide a method for manufacture thereof.Resolution MeansInclude a benzotriazole ultraviolet absorber containing one or more unsaturated bond in the molecule when manufacturing elastic yarn made of polyurethane with a polymeric diol and diisocyanate as starting material.