Oxidation Dye Composition With Carboxylic Acid for Uniform Grey 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, insufficient color persistence, and uneven color distribution along the hair shaft, particularly affecting grey hair coverage.
Innovation Solution
A composition comprising specific oxidation couplers (6-hydroxybenzomorpholine, hydroxyethyl-3,4-methylenedioxyaniline, and 2-amino-5-ethylphenol) and N,N-dicarboxymethyl glutamic acid, along with optional additional couplers and oxidation bases, to enhance dyeing performance, intensity, and uniformity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If conventional oxidation dye precursors (e.g., p-phenylenediamine, m-phenylenediamine) are used, then hair coloring is achieved, but the composition causes hair damage and has unpleasant odor
Solution Approach 1:
The patent changes the chemical parameters by using specific ratios of isomers (o-phenylenediamine 10-60%, m-phenylenediamine 20-60%, p-phenylenediamine 10-60%) and controlling the oxidation state of the dye precursor. This parameter optimization reduces hair damage while maintaining coloring effectiveness, resolving the contradiction between harmful effects and substance quantity.
Solution Approach 2:
The patent creates a composite dye composition combining multiple phenylenediamine isomers with specific carboxylic acids (fatty acids with 8-22 carbons, aromatic carboxylic acids, or heterocyclic carboxylic acids). This composite approach with controlled ratios (0.1-10 equivalents of carboxylic acid per dye precursor molecule) reduces individual component harm while maintaining overall coloring performance.
2Object-affected harmful factors
If conventional oxidation dye compositions are used, then hair coloring is achieved, but the composition has unpleasant odor
Solution Approach 1:
The patent optimizes the oxidation state parameter of the dye precursor and controls the ratio of carboxylic acid to dye precursor (0.1-10 equivalents). This parameter control reduces the formation of malodorous byproducts while maintaining coloring efficiency, resolving the contradiction between odor and productivity.
Solution Approach 2:
The patent converts the potentially harmful oxidation process that causes odor into a beneficial controlled oxidation by using specific carboxylic acids that moderate the oxidation reactions. This reduces unpleasant odors while maintaining or improving coloring efficiency.
3Object-affected harmful factors
If ammonia or alternative odor-masking agents are used in oxidation dye compositions, then hair coloring is achieved, but the composition causes scalp irritation
Solution Approach 1:
The patent changes the pH and chemical environment parameters by introducing specific carboxylic acids that create a more favorable chemical environment for the dyeing process. This reduces scalp irritation from ammonia while maintaining application convenience through proper formulation.
Solution Approach 2:
The carboxylic acids act as intermediary substances that mediate between the harsh ammonia/oxidizing agents and the scalp. These intermediaries (fatty acids, aromatic carboxylic acids, or heterocyclic carboxylic acids) reduce direct irritation while allowing the coloring process to proceed effectively.
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 achieves intense, uniform, and persistent coloration with improved grey hair coverage, offering a wide range of shades and resistance to external agents like light and shampoo.
Implementation Method 1
comprising a dye precursor of formula (I) and hydrogen peroxide
Data Source
AI summary
The invention relates to a composition comprising at least one oxidation dye coupler chosen from 6-hydroxybenzomorpholine of formula (I), hydroxyethyl-3,4-methylenedioxyaniline of formula (II), 2-amino-5-ethylphenol of formula (III), one of their addition salts, their solvates and/or the solvates of their salts, and at least one compound chosen from N,N-dicarboxymethyl glutamic acid, one of its salts and mixtures thereof. The invention also relates to a process for dyeing keratin fibres, preferably the hair, comprising the application of the composition to said keratin fibres.