Bis-azo Oxyalkylene Dyes for Laundry Whitening
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Solution Overview
Problem
Existing laundry dyes lack high water solubility and light fastness, leading to suboptimal whitening performance in domestic laundry applications.
Innovation Solution
The use of bis-azo oxyalkylene dyes with specific structures and surfactants in laundry formulations, which provide higher water solubility and light fastness, along with optional inclusion of other dyes and surfactants, to enhance textile whitening and reduce spotting.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional direct dyes are used in laundry formulations, then the formulation can provide whitening effect, but the dyes exhibit poor water solubility and low light fastness
Solution Approach 1:
The patent modifies the chemical structure of conventional direct dyes by introducing oxyalkylene groups (polyethylene oxide or polypropylene oxide chains) at positions 2 and/or 4 of the naphthyl ring. This structural parameter change simultaneously improves water solubility through the hydrophilic nature of oxyalkylene groups and enhances light fastness by modifying the dye's interaction with fabric and environment, directly resolving the contradiction between solubility and light fastness.
Solution Approach 2:
The invention creates a composite dye structure combining the chromophoric azo groups with oxyalkylene side chains. This composite molecular architecture integrates the light-absorbing functionality of azo dyes with the water-solubilizing and stabilizing properties of oxyalkylene groups, achieving both high solubility and improved light fastness in a single molecular entity.
2Reliability
If conventional direct dyes are used in laundry formulations, then the formulation can provide whitening effect, but the dyes exhibit suboptimal whitening performance
Solution Approach 1:
The patent optimizes the dye structure by controlling the length and position of oxyalkylene chains (with m+n values of 1-20, preferably 1-10) and their placement on the naphthyl ring. These parameter optimizations enhance the dye's affinity for cellulose fibers and its whitening efficiency, allowing effective whitening performance at lower concentrations compared to conventional dyes.
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 bis-azo oxyalkylene dyes demonstrate improved whitening performance and resistance to fading, with lower spotting on textiles, outperforming comparable dyes in prior art, especially when used in domestic washing machines.
Implementation Method 1
Direct Violet 9, direct violet 51, direct violet 99 and direct violet 35 are examples of such dyes
Data Source
AI summary
The present invention provides a dye for use in laundry applications.