Inorganic Buffer Systems for Hair Dye pH Stability
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Solution Overview
Problem
Existing hair dyes based on direct dyes face challenges with pH stability, leading to unpredictable color results and increased hair damage, particularly when formulated with organic buffer systems that tend to crystallize, affecting the buffering capacity and solubility.
Innovation Solution
A cosmetic agent for coloring keratinic fibers using a mixture of at least one direct dye and an inorganic buffer system comprising an inorganic acid and its corresponding salt, such as phosphoric acid and phosphate salts, which maintains pH stability even in solvent-containing formulations and during extended storage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If organic buffer systems are used in direct dye formulations, then pH adjustment is achieved, but crystallization occurs during storage which affects buffering capacity and solubility
Solution Approach 1:
The patent changes the chemical nature of the buffer system from organic to inorganic, specifically using phosphoric acid and its salts instead of organic acid buffers. This parameter change prevents crystallization while maintaining pH control precision, as the inorganic buffer system remains soluble and stable during extended storage periods.
Solution Approach 2:
The patent employs a simple, stable inorganic buffer system that does not require complex stabilization measures. The phosphoric acid-based buffer provides reliable pH control without the need for additional preservatives or stability-enhancing additives, making the formulation more robust during storage.
2Illumination intensity
If higher pH values are used to intensify color with direct dyes, then color intensity increases, but hair damage increases
Solution Approach 1:
The patent optimizes the pH value within a specific range (2.0-4.0) for acid dyes, balancing color intensity with hair damage reduction. This parameter optimization allows sufficient color uptake while minimizing the damaging effects of high alkalinity on hair structure.
Solution Approach 2:
The patent uses direct dyes that are already in their active colored form, eliminating the need for oxidative development processes. This copying approach applies the color directly without the harsh chemicals and high pH values required for permanent oxidation dyeing, thereby reducing hair damage while still achieving desired color intensity.
3Adaptability or versatility
If pH value is not precisely maintained, then formulation flexibility increases, but color reproduction and nuance stability deteriorate
Solution Approach 1:
The patent employs a buffer system that automatically maintains pH within the optimal range through equilibrium between phosphoric acid and its salts. This feedback mechanism ensures that even if minor variations occur during formulation or storage, the pH remains stable, guaranteeing consistent color reproduction and nuance 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
The inorganic buffer system ensures precise and reproducible pH control, preventing crystallization and maintaining color nuance stability, reducing hair damage, and ensuring consistent color results across different storage conditions and water hardness levels.
Implementation Method 1
an inorganic buffer system comprising at least one inorganic acid (b1) and at least one inorganic salt of this acid or these acids (b2)
Implementation Method 2
preventing crystallization and maintaining color nuance stability
Data Source
AI summary
An agent for coloring keratinic fibers, particularly human hairs, including in a cosmetic carrier (a) at least one direct dye, and (b) an inorganic butter system comprising at least one inorganic aid (b1) and at least one inorganic salt of this acid or these acids (b2), and (c) water. Further, a cosmetic product includes the aforementioned colorant which is packaged in a pressurized aerosol container possessing an aerosol dispensing device with spray valve. Finally, a method for increasing the nuance stability of colorants includes adding the aforementioned ingredients (a), (b), and (c) in the agent.