pH-Sensitive Reactive Dye with Expanded Neutral-Range Color Change
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Solution Overview
Problem
Current pH-sensitive reactive dyes have low dyeing rates on cotton fabrics and require strong acidic or alkaline conditions for color change, limiting their application in neutral environments, such as sweat detection.
Innovation Solution
Development of a reactive dye with a heterocyclic primary amine as a diazo component and a s-triazine active group, capable of forming stable covalent bonds with textiles, exhibiting color changes under weak alkali, weak acid, or neutral conditions through a reversible isomerization reaction.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If conventional pH-sensitive reactive dyes are used, then color change function is achieved, but dyeing rate on cotton fabrics is low and color yield is low
Solution Approach 1:
The patent modifies the chemical structure of the dye molecule by introducing a sulfonate group at the para position of the phenolic hydroxyl group. This structural parameter change enhances the dye's reactivity with cotton fabrics while maintaining its pH-sensitive color change property, thereby simultaneously improving both dyeing rate and color yield.
2Adaptability or versatility
If conventional pH-sensitive reactive dyes are used, then color change under strong acidic or alkaline conditions is achieved, but color change under neutral conditions cannot be observed
Solution Approach 1:
The introduction of the sulfonate group modifies the electronic distribution and pKa value of the phenolic hydroxyl group, enabling the dye to undergo reversible color change at neutral pH conditions. This allows the textile to detect sweat and other neutral substances, expanding the practical application range while maintaining reliable color change observability.
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 reactive dye achieves high color fixation rates (>50%) and excellent colorfastness to washing, rubbing, and sunlight, allowing for effective color change detection in a broader pH range, including neutral conditions.
Implementation Method 1
the reactive dye can establish a stable covalent bonding reaction with textiles
Implementation Method 2
pH-sensitive color-changing materials belong to the category of ionic color-changing materials, and their color changes in response to variations in pH levels
Implementation Method 3
exhibiting color changes under weak alkali, weak acid, or even neutral conditions through a reversible isomerization reaction
Data Source
AI summary
Disclosed are reactive dyes and preparation methods thereof. The reactive dye may be prepared using heterocyclic primary amine as a diazo component, 4,4′-diamino-2,2′-stilbenedisulfonic acid, s-triazine, or ethylenediamine as a bridging group, and a dimonochlortriazine group as an active group. The color-changing compound is covalently bonded into the fiber chemical structure by nucleophilic substitution reaction between monochlorotriazine and the hydroxyl group in a textile structure, and the size of the conjugated system and the range of electron delocalization of the dye are changed by a reversible isomerization reaction of the hydroxyl group adjacent to the diazo group and the diazo group under different pH regulations. Moreover, the dye has a double color changing structure, which improves the capability of the dye combined with —H/—OH. The pH value range that can cause color changes in the dye is effectively expanded to include weak alkali, weak acid or even neutral conditions.