Hair Dyeing Method Using Segmented Azo and Oxidation Agents
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Solution Overview
Problem
Existing permanent hair dye agents struggle to achieve vivid color tones that are both long-lasting and resistant to fading, as they often require the use of direct dyes which are unstable in alkaline or oxidizing environments.
Innovation Solution
A hair dyeing method that combines an oxidation dye precursor with an azo dye, where the azo dye is included in a separate agent that is mixed with the oxidation dye precursor and oxidizing agent just before application, allowing for a two-layered dyeing effect that changes hue or color tone with the viewing angle.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If direct dyes are used to achieve vivid color tones, then color vividness is improved, but fading resistance deteriorates
Solution Approach 1:
The dyeing composition is divided into two separate agents: Agent 1 containing oxidation dye precursors and Agent 2 containing direct dyes. This segmentation allows each dye type to function optimally without interfering with the other, enabling both vivid color and fading resistance to be achieved simultaneously.
Solution Approach 2:
The patent combines oxidation dyes and direct dyes in a two-agent system where both dye types work together on the hair. The oxidation dye provides long-lasting color penetration while the direct dye enhances color vividness, achieving a synergistic effect that resolves the contradiction between color strength and fading resistance.
2Duration of action of stationary object
If oxidation dyes are used to achieve deep penetration and long-lasting color, then durability is improved, but color vividness deteriorates
Solution Approach 1:
The patent merges oxidation dyes and direct dyes in a two-agent system where both dye types work together on the hair. The oxidation dye provides long-lasting color penetration while the direct dye enhances color vividness, achieving a synergistic effect that resolves the contradiction between color strength and fading resistance.
3Illumination intensity
If direct dyes are used to produce vivid colors, then color intensity is improved, but stability in alkaline environment deteriorates
Solution Approach 1:
The dyeing composition is divided into two separate agents: Agent 1 containing oxidation dye precursors and Agent 2 containing direct dyes. This segmentation allows each dye type to function optimally without interfering with the other, enabling both vivid color and fading resistance to be achieved simultaneously.
Solution Approach 2:
The oxidation dye precursor in Agent 1 is prepared in advance to create an alkaline environment that activates the precursor. When Agent 2 containing the direct dye is added, the direct dye is immediately incorporated into the hair structure before significant fading can occur, ensuring both color intensity and stability.
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
This method effectively achieves a vivid, long-lasting hair color that changes appearance depending on the viewing angle, overcoming the stability issues of direct dyes and enhancing the dyeing performance of permanent hair dyes.
Implementation Method 1
a second agent comprising an oxidizing agent
Data Source
AI summary
A hair dyeing method including the following steps (I) and (II): step (I): mixing a first agent comprising an alkaline agent and an oxidation dye precursor, a second agent comprising an oxidizing agent, and a third agent comprising one or more dyes (A) selected from the group consisting of the following (A-1), (A-2), and (A-3), having a pH at 25℃ of 7.5 or more and 12 or less when diluted to be 10 times by mass with water; and step (II): applying a mixed solution prepared in step (I) on hair.