Hair Coloring Method Using Basic Dyes and Alkaline Agents
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Solution Overview
Problem
Existing hair coloring methods using paraphenylenediamine-based dyes cause skin damage, difficulty in removing semi-permanent dyes, and fail to maintain color quality, especially for dark colors and hair edges.
Innovation Solution
A hair coloring method involving a mixture of a hair coloring agent with basic dyes, thioglycolic acid, and cysteine derivatives, and a hair cosmetic composition with alkaline agents and higher alcohols, applied in a specific ratio to achieve pH 3.5 or higher, allowing deep penetration and color retention without paraphenylenediamine.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If paraphenylenediamine-based oxidative dyes are used for hair coloring, then dyeing power and color depth are improved, but skin damage and allergic reactions increase
Solution Approach 1:
The invention extracts and removes the harmful paraphenylenediamine component from the hair coloring composition while retaining the desired dyeing效果 through alternative dyeing mechanisms using basic dyes and HC dyes that do not cause skin damage
Solution Approach 2:
The invention uses semi-permanent basic dyes and HC dyes that are safer for skin but traditionally had poor color retention, combining them with cuticle-opening agents to achieve both safety and durability
2Manufacturing precision
If semi-permanent hair dye is left on scalp for extended period, then color penetration is improved, but difficulty in removing dye increases
Solution Approach 1:
The invention applies cuticle-opening agents (ammonium hydroxide, ammonium carbonate, or amino acids) before applying the basic dye to preliminarily open the hair cuticle, allowing better dye penetration without requiring extended exposure time, thus maintaining ease of removal
Solution Approach 2:
The invention uses pH-adjustable cuticle-opening agents that dynamically open the cuticle during application and allow natural closure afterward, enabling controlled penetration without permanent damage or difficult removal
3Ease of operation
If hair color treatment targets cuticle and cortex near surface, then application ease is improved, but color quality retention deteriorates
Solution Approach 1:
The invention applies different functions to different parts of the hair structure: cuticle-opening agents target the cuticle layer for easy application, while basic dyes and HC dyes penetrate into the cortex for durable color retention, achieving both application ease and color quality
4Manufacturing precision
If amount of diamine-based compound is increased for dark black color, then color depth is improved, but skin damage risk increases
Solution Approach 1:
The invention completely removes diamine-based compounds from the formulation and replaces them with basic dyes and HC dyes that achieve comparable or superior color depth without the skin damage risks associated with paraphenylenediamine
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 reduces hair damage, minimizes skin irritation, and maintains color quality, enabling effective dyeing of hair edges and deeper hair parts with improved dye penetration and longevity.
Implementation Method 1
a mixture of (A) a hair coloring agent... and (B) a hair cosmetic comprising at least an alkaline agent... wherein the pH of the hair coloring agent is pH 3.5 or higher
Implementation Method 2
a hair coloring agent comprising at least a basic dye, a HC dye... and at least one selected from the group consisting of thioglycolic acid, cysteine, 3-mercapto-1,2-propanediol, cysteamine
Data Source
AI summary
A hair coloring method may include a step of applying a mixture of the following (A) and (B) in a predetermined ratio: (A) a hair coloring agent comprising at least a basic dye, a HC dye, a second amino acid, a first cationic surfactant, a thickener, an oil agent, a first pH adjusting agent, a wetting agent and at least one selected from the group consisting of thioglycolic acid, cysteine, 3-mercapto-1,2-propanediol, cysteamine, and derivatives and salts thereof, wherein the pH of the hair coloring agent is pH 3.5 or higher, and (B) a hair cosmetics comprising at least an alkaline agent, a first amino acid, higher alcohols having 12 to 22 carbon atoms, a surfactant, and a thickener. The hair coloring method may further include a step of providing a predetermined time after the application.