Vinyl Ester Disperse Azo Dyestuffs for Polyester Wash Fastness
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Solution Overview
Problem
Conventional disperse dyes for hydrophobic fibers, such as polyester, often lack sufficient wash fastness properties, leading to color loss during washing.
Innovation Solution
Development of disperse azo dyestuffs containing a vinyl ester group in the coupling component, which provides improved wash fastness when used for dyeing polyester fibers, utilizing specific diazo components and coupling processes to achieve optimal dye fixation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional disperse dyes are used for polyester fibers, then the dyeing process is simple and cost-effective, but the wash fastness properties are insufficient leading to color loss
Solution Approach 1:
The invention modifies the chemical structure of the coupling component by introducing a vinyl ester group at specific positions (R1, R2, R4) of the naphthalene ring system. This structural parameter change in the disperse azo dye molecule enhances its affinity and bonding with polyester fibers, thereby improving wash fastness without fundamentally changing the dyeing process parameters
Solution Approach 2:
The invention creates a composite molecular structure by combining the vinyl ester functional group with the azo chromophore and naphthalene coupling component. This composite structure integrates the benefits of vinyl ester groups (known for improved fastness) with the established azo dye framework, achieving enhanced wash fastness while maintaining the disperse dye classification
2Reliability
If the vinyl ester group is introduced into the coupling component, then wash fastness is improved, but the synthesis process becomes more complex
Solution Approach 1:
The synthesis is divided into two distinct stages: first, preparation of the vinyl ester-containing coupling component through reaction of a naphthalene derivative with vinyl ester reagents; second, diazotization of the amine and coupling to form the final azo dye. This segmentation allows each step to be optimized independently, managing synthesis complexity while achieving the desired wash fastness improvement
3Duration of action of stationary object
If standard dyes are used for hydrophobic fibers, then the application range is broad, but the color durability after washing is poor
Solution Approach 1:
The invention introduces vinyl ester groups at specific local positions (R1, R2, or R4) of the naphthalene coupling component rather than throughout the entire molecule. This localized modification provides enhanced wash fastness at critical interaction points with the fiber while maintaining the overall molecular properties needed for broad applicability to polyester and other hydrophobic fibers
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 use of vinyl ester-containing disperse azo dyestuffs results in dyeings with excellent wash fastness properties, maintaining color intensity and durability even after multiple wash cycles.
Implementation Method 1
the amine of the formula (III) may be diazotised in an acidic medium, such as acetic, propionic or hydrochloric acid using a nitrosating agent such as nitrosylsulphuric acid, sodium nitrite or methylnitrite
Implementation Method 2
Coupling onto the compound of the formula (IV) may be achieved by adding the diazotised amine to the compound of the formula (IV)
Data Source
AI summary
The present invention claims dyestuffs of the formula I wherein D, R1 to R5, m and n are defined as given in claimi, a process for their preparation, their use and and inks for ink jet printing containing them.