Halogen-Cyano Substituted Azo Dyes for Enhanced Textile Fastness
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Solution Overview
Problem
Current azo dyes based on aminophthalimides and 2,6-aminosubstituted 3-cyano-4-methylpyridines do not consistently meet modern requirements for light fastness and washing fastness in dyeing or printing of textile materials.
Innovation Solution
Development of azo dyes using halogen- and cyanosubstituted phthalimides as diazo components combined with specific 2,6-aminosubstituted 3-cyano-4-methylpyridines as coupling components, which exhibit improved washing fastness and excellent light fastness properties.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional azo dyes based on aminophthalimides and 2,6-aminosubstituted 3-cyano-4-methylpyridines are used, then the dyeing process is simple and cost-effective, but the light fastness and washing fastness properties are insufficient
Solution Approach 1:
The patent applies parameter changes by modifying the chemical structure of the diazo component from conventional aminophthalimides to halogen- and cyanosubstituted phthalimides. Specifically, introducing halogen atoms (Cl, Br) at positions 2 and 4, and cyano groups at position 3 of the phthalimide ring, creates new molecular parameters that enhance light fastness and washing fastness while maintaining the disperse dye classification and applicability to synthetic fibers
Solution Approach 2:
The patent employs composite material principles by creating hybrid molecular structures that combine multiple functional groups (halogen, cyano, phthalimide, and pyridine rings) into a single dye molecule. This composite approach integrates the electron-withdrawing properties of halogen and cyano groups with the chromophoric phthalimide-pyridine system, resulting in enhanced fastness properties while maintaining dyeing performance
2Reliability
If new azo dyes with improved fastness properties are developed, then light fastness and washing fastness are enhanced, but the synthesis process becomes more complex
Solution Approach 1:
The patent applies segmentation by dividing the dye synthesis into two independent stages: first synthesizing the halogen- and cyanosubstituted phthalimide diazo component, then coupling it with the 2,6-aminosubstituted 3-cyano-4-methylpyridine. This segmented approach allows each component to be optimized separately and simplifies the overall manufacturing process compared to attempting to synthesize the complete complex molecule in a single step
Solution Approach 2:
The patent employs preliminary action by pre-synthesizing and characterizing the halogen- and cyanosubstituted phthalimide diazo component before the coupling reaction. This preliminary preparation of the diazo component with specific halogen and cyano substitutions enables controlled optimization of fastness properties independent of the coupling component selection, streamlining the manufacturing process
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 new azo dyes demonstrate very high light fastness and washing fastness, suitable for use in semi-synthetic and synthetic textile materials, particularly polyester, with minimal impact on wool and cotton, and can be applied in various dyeing and printing processes.
Implementation Method 1
They can be prepared by the process described in WO 2014/016072, i.e. by synthesis of the dye of formula (2) according to the method disclosed in U.S. Pat. No. 3,980,634 and subsequent reaction with NaCN/CuCN
Data Source
AI summary
The present invention relates to azo dyes of formulawhereinR1 denotes hydrogen or C1-C12alkyl which is unsubstituted or substituted by one or more C1-C12alkoxy groups, C1-C12alkylcarbonyl groups, C7-C25arylcarbonyl groups, hydroxyl groups, amino groups, cyano groups or halogen atoms and which may be interrupted one or more times by the radical —O—, —S—, —NR4—, —COO— or —OOC—, R4 is hydrogen or C1-C12alkyl;X is hydrogen or halogen; andR2 and R3 are each independently of the other hydrogen; C1-C12alkyl which is unsubstituted or substituted by cyano, carboxy, hydroxy, C1-C6alkoxy or C2-C8alkoxyalkoxy; or are C7-C25aralkyl which is unsubstituted or substituted by cyano, carboxy, hydroxy, C1-C6alkoxy or C2-C8alkoxyalkoxy,to mixtures containing said dyes and to the use thereof in dyeing or printing semi-synthetic and especially synthetic hydrophobic fibre materials, more especially textile materials.