Oxidative Hair Dye Composition with Optimized Developer Coupler Ratio
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Solution Overview
Problem
Current oxidative hair dyes, particularly those aiming for red, violet, and copper shades, face suboptimal wash fastness and light fastness, leading to undesirable color changes and fading.
Innovation Solution
A cosmetic agent containing specific combinations of oxidation dye precursors, including 4,5-diamino-1-(2-hydroxyethyl)-1H-pyrazole, p-aminophenol derivatives, m-diaminobenzene derivatives, and m-dihydroxybenzene derivatives, in precise molar ratios, particularly with a developer-to-coupler ratio of at least 1.2, to enhance the fastness properties of keratin fiber dyes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional oxidative dyes are used for red, violet, and copper shades, then the hair color can be changed to desired fashion shades, but the wash fastness and light fastness are suboptimal, leading to color fading and change
Solution Approach 1:
The patent applies parameter changes by optimizing the molar ratio of developer to coupler (at least 1.2:1) and specifying precise concentration ranges for each component (4,5-diamino-1-(2-hydroxyethyl)-1H-pyrazole at 0.5-5.0%, p-aminophenol derivatives at 0.3-3.0%, m-diaminobenzene derivatives at 0.3-3.0%, and m-dihydroxybenzene derivatives at 0.3-3.0%). These parameter optimizations resolve the contradiction by achieving superior fastness properties through controlled chemical ratios while maintaining formulation feasibility
Solution Approach 2:
The patent employs composite materials by combining four specific types of oxidation dye precursors in defined proportions: 4,5-diamino-1-(2-hydroxyethyl)-1H-pyrazole, p-aminophenol derivatives, m-diaminobenzene derivatives, and m-dihydroxybenzene derivatives. This composite approach creates a synergistic effect that improves wash and light fastness beyond what individual components could achieve alone, resolving the reliability enhancement need
2Duration of action of stationary object
If direct dyes are used for temporary hair color change, then the hair damage is minimal, but the durability and wash resistance are low, causing quick color washout
Solution Approach 1:
The patent resolves this contradiction by changing the chemical reaction parameters through oxidation dyeing, where the developer-to-coupler molar ratio of at least 1.2:1 ensures complete reaction and stable dye formation within the hair fiber. This parameter control allows the color to penetrate deeply and bond permanently, achieving high durability while the controlled oxidation process minimizes hair damage compared to more aggressive dyeing methods
Solution Approach 2:
The patent uses oxidation products as intermediaries that form stable covalent bonds within the hair fiber structure. The oxidative coupling reaction creates indophenol and indoaniline dyes that are trapped within the hair cortex, serving as a permanent intermediary that resists washing out. This intermediary mechanism achieves long-lasting color while the gradual oxidation process is gentler than direct harsh dye application
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 agent achieves improved wash fastness and light fastness, resulting in more stable and long-lasting hair colors with reduced color change and fading, especially for red, violet, and copper shades.
Implementation Method 1
oxidative color changing agents are usually used. So-called oxidation dyes are used for permanent, intensive dyeing with appropriate fastness properties. Such colorants usually contain oxidation dye precursors, so-called developer components and coupler components, which form the actual dyes under the influence of oxidizing agents.
Implementation Method 2
oxidation dye precursors, so-called developer components and coupler components, which form the actual dyes under the influence of oxidizing agents
Data Source
AI summary
The present invention provides a composition for the oxidative colouring of keratinous fibres, comprising in a cosmetic vehicle (A) as developer 4,5-diamino-1-(2-hydroxyethyl)-1H-pyrazole and/or a physiologically tolerated salt thereof, (B) as developer at least one p-aminophenol derivative from the group of p-aminophenol, 4-amino-3-methylphenol and/or a physiologically tolerated salt thereof, (C) as coupler at least one m-diaminobenzene derivative from the group of 2-(2,4-diaminophenoxy)ethanol, 1-methoxy-2-amino-4-(2'-hydroxyethylamino)benzene and/or a physiologically tolerated salt thereof, (D) as coupler at least one m-dihydroxybenzene derivative from the group of resorcinol, 2-methylresorcinol and/or 4-chlororesorcinol, the molar ratio of all group (A) developers to all group (B) developers in the composition, i.e. the molar ratio (A)/(B), being at least 1.2.