Disperse azo dyes, a process for the preparation thereof and the use thereof
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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 excellent light fastness and washing 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 or printing process can be performed, but the light fastness and washing fastness of the dyeings do not satisfy modern requirements
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 3 and/or 5, and cyano groups at positions 2 and/or 4 of the phthalimide ring system. These structural parameter changes result in improved light fastness (up to 8-9 on the blue scale) and washing fastness (up to 6-7 on the blue scale) while maintaining acceptable manufacturing processes.
2Reliability
If new azo dyes with improved light fastness are developed, then excellent light fastness and washing fastness are achieved, but the dye structure becomes more complex with multiple substituents
Solution Approach 1:
The patent applies local quality by strategically placing specific functional groups (halogen and cyano) at defined positions on the phthalimide ring structure. Rather than random substitution, the halogen atoms are positioned at 3 and/or 5 positions while cyano groups are placed at 2 and/or 4 positions. This localized, position-specific substitution pattern achieves the desired fastness properties while maintaining a systematic and manageable molecular complexity.
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 fibers, with minimal coloration of wool and cotton, and can be used in various dyeing and printing processes.
Implementation Method 1
conventional coupling reaction of the relevant diazonium salt with the respective coupling component
Implementation Method 2
by synthesis of the dye of formula (1) according to the method disclosed in US 3,980,634
Data Source
AI summary
The present invention relates to azo dyes of formula (1), wherein R1 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; and R2 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; C6-C24aryl which is unsubstituted or substituted by cyano, carboxy, hydroxy, C1-C12alkyl, C1-C6alkoxy or C2-C8alkoxyalkoxy; or are C7-C25aralkyl which is unsubstituted or substituted by cyano, carboxy, hydroxy, C1-C12alkyl, 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.