Coppery Hair Dye Composition Using Neutral pH Oxidation
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Solution Overview
Problem
Current hair dye compositions using oxidation bases and couplers struggle to achieve a wide range of warm shades, particularly coppery shades, while maintaining color intensity, uniformity, and resistance to external agents like shampoos, light, and sweat.
Innovation Solution
A composition comprising 2,3-diamino-6,7-dihydro-1H,5H-pyrazolo[1,2-a]pyrazol-1-one as the oxidation base, 6-chloro 2-methyl 5-amino phenol as the first coupler, and a substituted meta-aminophenol as the second coupler, with specific molar ratios and structural modifications, applied at neutral pH to achieve intense, chromatic, and resistant coppery shades on gray or white hair.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If oxidation bases such as para-phenylenediamine and para-aminophenol derivatives are used, then a fairly wide range of colors can be obtained at basic pH, but good chromaticity and color intensity are not achieved
Solution Approach 1:
The patent changes the pH parameter from basic to neutral, and modifies the chemical structure by using 2,3-diamino-6,7-dihydro-1H,5H-pyrazolo[1,2-a]pyrazol-1-one as oxidation base combined with specific couplers (6-chloro 2-methyl 5-aminophenol and substituted meta-aminophenols). This parameter change enables achieving good chromaticity and color intensity while maintaining a wide color range at neutral pH.
2Reliability
If neutral pH bases are used, then color uniformity and tenacity to external agents can be achieved, but a varied shade range especially for warm shades such as reds and oranges is not obtained
Solution Approach 1:
The patent uses a composite dyeing system combining 2,3-diamino-6,7-dihydro-1H,5H-pyrazolo[1,2-a]pyrazol-1-one as oxidation base with two specific couplers: 6-chloro 2-methyl 5-aminophenol and substituted meta-aminophenols. This composite approach at neutral pH achieves both color uniformity/tenacity and a varied shade range including warm shades like reds and oranges.
3Reliability
If existing oxidation base and coupler combinations are used, then coloring can be achieved, but coppery shades that are powerful, chromatic, aesthetic, and resistant to external agents cannot be obtained
Solution Approach 1:
The patent achieves powerful, chromatic coppery shades resistant to external agents by changing the chemical parameters: using 2,3-diamino-6,7-dihydro-1H,5H-pyrazolo[1,2-a]pyrazol-1-one combined with 6-chloro 2-methyl 5-aminophenol and substituted meta-aminophenols at neutral pH, with specific molar ratios (first oxidation base/first coupler < 1.5, first oxidation base/second coupler > 1).
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 effectively produces coppery shades on gray or white hair with high chroma and lightness values, ensuring color stability against environmental and chemical attacks, and provides intense, uniform, and long-lasting color.
Implementation Method 1
The precursors of oxidation dyes, or oxidation bases, are colorless or weakly colored compounds which, associated with oxidizing products, can give rise, through an oxidative condensation process, to colored or coloring compounds.
Data Source
AI summary
The invention relates to a keratin fiber coloring composition comprising 2,3-diamino-6,7-dihydro-1H,5H-pyrazolo[1,2-a]pyrazol-1-one as the first oxidation base, 6-chloro-2-methyl-5-aminophenol as the first coupler, and a substituted meta-aminophenol of a determined formula as the second coupler, provided that the molar ratio of first oxidation base to first coupler is less than 1.5, the molar ratio of first oxidation base to second coupler is greater than 1, and the molar quantity of the first oxidation base is greater than or equal to 2.5 x 10⁻³ moles per 100 g of composition. The present invention makes it possible to obtain a powerful, highly chromatic, aesthetically pleasing, low-selectivity, and long-lasting copper-toned coloring of keratin fibers. Furthermore, it allows for intense coloring at neutral pH.