Oxidation Hair Dye Composition for Uniform Gray Coverage
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Solution Overview
Problem
Existing hair dye compositions using oxidation dye precursors often result in unsatisfactory dyeing power, limited color range, poor persistence, and selective color distribution along the hair shaft, particularly at the root and ends.
Innovation Solution
A composition comprising 2-γ-hydroxypropyl-para-phenylenediamine, 2-amino-4-hydroxyethylaminoanisole or 2-amino-5-ethylphenol as oxidation dye precursors, an amphoteric or zwitterionic surfactant, and a solid fatty substance, combined with a chemical oxidizing agent, to achieve intense, uniform, and persistent coloration.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If conventional oxidation dye precursors are used, then the dyeing process is simple, but the dyeing power is weak and color range is limited
Solution Approach 1:
The patent combines multiple oxidation dye precursors (ortho-aminophenol, para-aminophenol, and heterocyclic compounds) with specific couplers to create a composite dyeing system. This composite approach enables intense coloration while maintaining process simplicity, resolving the contradiction between ease of manufacture and dyeing power.
2Ease of operation
If conventional oxidation dye precursors are used, then the application is straightforward, but the color persistence is poor
Solution Approach 1:
The patent modifies the chemical parameters of the dye precursors by selecting specific compounds (ortho-aminophenol, para-aminophenol, heterocyclic compounds with 1-3 nitrogen atoms) and optimizing their combinations with couplers. These parameter changes enhance color persistence while keeping the application method straightforward.
3Device complexity
If conventional oxidation dye precursors are used, then the formulation is simple, but the color distribution is selective and non-uniform
Solution Approach 1:
The patent employs different oxidation dye precursors and couplers that interact with different regions of the hair fiber. The combination of ortho-aminophenol, para-aminophenol, and heterocyclic compounds with specific couplers creates local quality variations that result in uniform overall color distribution, addressing the non-uniformity issue while maintaining simple formulation.
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 composition provides powerful, intense, and sparingly selective colorings with good coverage of gray hair, achieving uniform color along the hair length and improved persistence against external agents.
Implementation Method 1
These oxidation bases are colorless or weakly colored compounds which, when combined with oxidizing products, can give rise to colored compounds via a process of oxidative condensation.
Data Source
AI summary
The invention relates to a composition comprising at least one oxidation dyeing base chosen from 2-γ-hydroxypropyl-para-phenylenediamine of formula (I), an addition salt thereof, solvates thereof and/or solvates of the salts thereof, at least one oxidation dyeing coupler chosen from (i) 2-amino-4-hydroxyethylaminoanisole of formula (II), an addition salt thereof, solvates thereof and/or solvates of the salts thereof and (ii) 2-amino-5-ethylphenol of formula (III), an addition salt thereof, solvates thereof and/or solvates of the salts thereof, at least one amphoteric or zwitterionic surfactant and at least one solid fatty substance.The invention also relates to a process for dyeing keratin fibers, preferably the hair, which comprises the application of the composition to said keratin fibers.