Cationic Azo Dyes for Oxidative Hair Coloring
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing hair dye technologies face challenges with nonoxidative colorants, which have lower durability and uneven color distribution, and are unable to lighten hair due to instability under oxidative conditions.
Innovation Solution
Development of cationic azodyes with a specific formula that are oxidation-stable, allowing for intense and durable coloring of keratin fibers, including the ability to lighten hair when used in oxidative systems.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If nonoxidative colorants are used, then the coloring process is gentle and causes low damage to keratin fibers, but the durability and evenness of color are lower
Solution Approach 1:
The patent changes the chemical parameters of the colorant by developing cationic azo dyes with specific molecular structures (formula I) that possess oxidation stability. This allows the dye to function effectively in oxidative systems while maintaining fiber compatibility, thereby improving color durability and evenness without excessive damage to keratin fibers.
Solution Approach 2:
The invention creates a composite coloring system that combines cationic azo dyes with oxidative agents. This composite approach enables the dye to benefit from both the gentleness of nonoxidative methods and the durability of oxidative methods, achieving a balance between fiber protection and color performance.
2Ease of operation
If direct dyes are used for nonoxidative coloring, then the process is easy to use and gentle on fibers, but the colorants cannot lighten hair due to instability under oxidative conditions
Solution Approach 1:
The patent modifies the chemical parameters of azo dyes by introducing cationic groups and specific heterocyclic structures that confer oxidation stability. This enables the dye to withstand oxidative conditions required for lightening, expanding its versatility while maintaining ease of application.
Solution Approach 2:
The cationic azo dyes of formula (I) are designed to perform multiple functions: they can be used in both nonoxidative and oxidative coloring systems, and can achieve both coloring and lightening effects. This multi-functionality eliminates the need for separate dye systems for different hair treatment goals.
3Quantity of substance
If cationic azo dyes with localized charge are used for synthetic fibres, then the dyeing effect is achieved, but they cannot be used for keratin fibers requiring oxidation stability
Solution Approach 1:
The patent fundamentally changes the chemical parameters of cationic azo dyes by delocalizing the positive charge throughout the conjugated system rather than localizing it in side chains. This structural modification confers oxidation stability while maintaining effective dyeing of keratin fibers, bridging the gap between synthetic fiber dyes and hair coloring requirements.
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 cationic azodyes provide strong, even color with good durability and mildness to hair, enabling both coloring and lightening capabilities in oxidative systems.
Implementation Method 1
colorants which comprise cationic azo dyes, in which the positive charge is delocalised in the conjugated system
Implementation Method 2
an agent for the simultaneous lightening and coloring of keratin fibers, in particular human hair, which, besides the dye of the formula (I), comprises an oxidizing agent
Data Source
AI summary
The present invention relates to agents for coloring keratin fibers which comprise at least one cationic azodye of the general formula (I).