Freshly Bleached Hair Coloring pH Control for Even Tone
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Solution Overview
Problem
Existing hair dye compositions struggle with uneven color distribution from roots to tips, unpredictable color results, and hair damage, particularly in freshly bleached hair, due to variations in damage levels and pH sensitivity.
Innovation Solution
A method involving bleaching hair, applying a pH 7.0 to 8.0 hair coloring composition with a buffering system, leaving it on for 10 minutes or less, and rinsing it out, which allows for a pH drop to 6.8 to 7.2, ensuring even coloration and minimal damage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If a high pH hair coloring composition (pH 8.5-10) is used to ensure color uptake, then color intensity is improved, but root-to-tip evenness deteriorates with tips becoming darker than roots
Solution Approach 1:
The patent applies parameter changes by adjusting the pH of the hair coloring composition to a slightly alkaline range (pH 7.5-8.5), which is lower than conventional compositions. This pH modification enables adequate color uptake while preventing excessive penetration into damaged areas, thereby achieving both color uniformity and reduced hair damage.
2Object-affected harmful factors
If the pH is lowered to slightly alkaline or acidic ranges to make composition milder, then hair damage is reduced, but color uniformity deteriorates with excessive color uptake on damaged hair
Solution Approach 1:
The patent identifies that conventional mild compositions (pH < 7.5) cause uneven color distribution on damaged hair. By optimizing the pH to the slightly alkaline range of 7.5-8.5, the composition achieves better control over color uptake, preventing oversaturation of damaged areas while maintaining adequate penetration in healthy areas, thus resolving the contradiction between mildness and uniformity.
3Manufacturing precision
If a conventional pH 8.5-10 hair coloring composition is used, then color intensity is achieved, but root-to-tip evenness deteriorates
Solution Approach 1:
The patent addresses color uptake variability by modifying the pH parameter to 7.5-8.5, which creates a more controlled chemical environment for dye penetration. This pH optimization reduces the variability in color uptake across different hair conditions (virgin, previously colored, damaged), thereby achieving consistent root-to-tip evenness while maintaining desired color intensity.
4Manufacturing precision
If the development time is extended to improve color uptake, then color intensity is improved, but hair damage increases
Solution Approach 1:
The patent resolves the contradiction between color intensity and hair damage by optimizing the pH parameter to 7.5-8.5. This pH modification enhances the efficiency of the coloring process, allowing adequate color uptake in a shorter development time (5-10 minutes), thereby achieving desired color intensity while minimizing exposure time and reducing hair damage.
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 method achieves satisfactory root-to-tip evenness, desired color intensity, and reduced hair damage by maintaining a pH drop during the application process, providing a streamlined and effective hair treatment.
Implementation Method 1
applying a hair colouring composition onto hair, wherein the hair colouring composition has a pH from 7.0 to 8.0, preferably a pH of more than 7.2 up to 8.0, more preferably from 7.3 to 8.0, and comprises a buffering system
Implementation Method 2
leaving the hair colouring composition for 10 minutes or less on hair, wherein the composition has a pH which over development time on hair drops by at least 0.20 unit to the range from 6.8 to 7.2
Data Source
AI summary
The present invention relates to a method for treating freshly bleached hair, a composition and use thereof.