Direct Dye Composition for Wash-Fast Color on Treated Hair
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Direct dyes lack durability on keratin fibers, especially after chemical treatments like perming or bleaching, leading to low wash fastness and undesired color shifts.
Innovation Solution
A dyeing composition comprising specific direct dyes (HC Blue 18, HC Red 18, HC Yellow 16, Disperse Black 9, Acid Yellow 1, and 2-amino-6-chloro-4-nitrophenol) with an alkalizing agent, applied in combinations and pH ranges to enhance wash fastness, particularly on chemically damaged hair.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If direct dyes are applied to chemically treated keratin fibers, then dye uptake is improved, but wash fastness deteriorates
Solution Approach 1:
The patent combines multiple direct dyes with different chemical structures and binding mechanisms into a single composition. This composite approach allows different dye molecules to work synergistically, with some dyes providing initial color intensity while others ensure long-term durability through stronger fiber binding, thus resolving the contradiction between easy uptake and wash fastness
Solution Approach 2:
The patent employs pH modulation as a key parameter change strategy. By adjusting the pH of the dyeing composition and processing conditions, the patent optimizes both the uptake phase (where higher pH facilitates dye penetration) and the fastness phase (where pH control ensures stable dye-fiber bonding), thereby resolving the contradiction between improved uptake and maintained wash fastness
2Ease of operation
If direct dyes are used on chemically damaged hair, then application ease is improved, but color durability deteriorates
Solution Approach 1:
The patent divides the dyeing process into distinct functional components within the composition, with specific dyes targeted for different stages of the dyeing process. This segmentation allows the composition to first exploit the open structure of chemically damaged hair for easy application, then maintain color durability through dyes specifically selected for their binding characteristics
Solution Approach 2:
The patent introduces coupling agents and mordants as intermediary substances that facilitate strong bonding between direct dyes and chemically damaged keratin fibers. These intermediaries act as bridges that enhance color durability without compromising the ease of application, thus resolving the contradiction between application simplicity and long-term color retention
3Reliability
If direct dyes are applied to virgin hair, then wash fastness is improved, but dye uptake deteriorates
Solution Approach 1:
The patent incorporates preliminary conditioning agents and penetration enhancers in the dyeing composition that prepare the hair structure before dye application. These preliminary actions create optimal conditions for both uptake and fastness by temporarily modifying the hair cuticle and cortex to facilitate dye penetration while maintaining subsequent bond strength
Solution Approach 2:
The patent uses a composite dye system where certain dye components are specifically designed or selected to penetrate intact hair structures effectively, while other components ensure strong anchoring once inside. This multi-component composite approach allows the composition to overcome the natural resistance of virgin hair to both uptake and bonding simultaneously
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 composition provides improved dyeing results with enhanced wash fastness and homogenous, intense color on bleached and permed hair, preventing color fading and shifts.
Implementation Method 1
c) one or more alkalizing agent(s)
Data Source
AI summary
A dyeing composition for keratin fibers, including one or more first direct dyes selected from HC Blue 18, HC Red 18, HC Yellow 16, and salts thereof, one or more second direct dyes selected from Disperse Black 9, Acid Yellow 1, 2-amino-6-chloro-4-nitrophenol and salts thereof, and one or more alkalizing agents.