Novel "water based" yellow dyeing system for finishing application

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Solution Overview

Problem

Conventional leather dyes face challenges in achieving high PVC migration fastness and water spot resistance while maintaining light fastness and colour stability, with existing dyes often showing poor PVC migration fastness and high water solubility leading to decreased water spot resistance.

Innovation Solution

A dye composition comprising anionic azo yellow dye (C.I. acid yellow 42) and anionic metal-complex azo dye (C.I. acid yellow 232 or C.I. acid yellow 194) in combination with water-miscible organic solvents and water, optimized in specific weight ratios to enhance PVC migration and water spot resistance.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Quantity of substance

If conventional leather dyes with high water solubility are used, then good dyeing performance is achieved, but water spot resistance decreases

Engineering Contradiction:
Improvewater solubilityVSAvoidwater spot resistance
Core Design Contradiction:
Quantity of substanceVSReliability

Solution Approach 1:

The patent combines anionic azo yellow dye and anionic metal-complex azo dye in a water-miscible organic solvent system to create a composite dye composition that achieves both high water solubility for good dyeing performance and high water spot resistance, resolving the contradiction between these two properties

Inventive Principle:
Principle #40Composite materials

Solution Approach 2:

The patent optimizes the weight ratio parameters of the dye components (0.1:1 to 1:1 ratio of anionic azo yellow dye to anionic metal-complex azo dye) and solvent composition to achieve the optimal balance between water solubility and water spot resistance, demonstrating parameter changes to resolve the contradiction

Inventive Principle:
Principle #35Parameter changes

2Ease of operation

If conventional spray dyes are used, then application ease is improved, but PVC migration fastness deteriorates

Engineering Contradiction:
Improvespray application easeVSAvoidPVC migration fastness
Core Design Contradiction:
Ease of operationVSReliability

Solution Approach 1:

The patent uses a composite dye system combining anionic azo yellow dye and anionic metal-complex azo dye in a water-miscible organic solvent, which maintains spray application ease while achieving high PVC migration fastness (3-5 rating), resolving the contradiction between ease of operation and reliability

Inventive Principle:
Principle #40Composite materials

Solution Approach 2:

The patent optimizes the composition parameters including organic solvent content (5.0-60.0% by weight) and water content (30.0-75.0% by weight) to achieve the right balance between sprayability and migration resistance, demonstrating how parameter changes resolve the contradiction

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 composition achieves high PVC migration fastness and water spot resistance, along with excellent light fastness and colour stability, providing uniform and consistent shades with reduced dye quantities and improved environmental compliance.

Implementation Method 1

Leather dyes refer to dyes with an affinity to leather and for leather colouring

Methodology Applied
Scientific EffectAffinity: Adsorption

Data Source

PatentEP3434736B1Novel "water based" yellow dyeing system for finishing application
Publication Date: 2023.04.12 STAKHL INT BV

AI summary

The present invention relates to an anionic dye composition comprising at least one azo dye and at least one azo-metal complex dye. The present invention further relates to the dye composition for use in dyeing leather, in particular spray dyeing leather.