Styryl Thiol Disulfide Fluorescent Dyes for Hair Lightening
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Solution Overview
Problem
Conventional methods for lightening keratin fibers, such as hair, using bleaching agents degrade the fibers and are incompatible with shape-modifying treatments, while existing fluorescent dyes lack tenacity and selectivity between the root and tip of hair fibers.
Innovation Solution
A process involving the application of thiol or disulfide fluorescent dyes, specifically those of the formula (I), which are applied in a cosmetic medium to achieve lightening effects on dark hair without degrading the fibers, providing tenacity against shampoos and external agents, and ensuring low coloring selectivity between the root and tip.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If conventional bleaching systems (hydrogen peroxide, persalts) are used to lighten keratin fibers, then the lightening effect is achieved, but the keratin fibers are degraded and their cosmetic properties are altered
Solution Approach 1:
The invention changes the chemical nature of the coloring agents from oxidizing bleaching systems to fluorescent dyes with specific molecular structures (formula I). This parameter change allows achieving lightening effects through fluorescence rather than oxidation, thereby preserving fiber quality while obtaining the desired illumination effect.
Solution Approach 2:
The invention converts the harmful oxidizing action into a beneficial fluorescent effect. Instead of using aggressive oxidants that damage fibers, the patent employs fluorescent compounds that absorb UV light and emit visible light, creating a lightening effect without the harmful side effects of conventional bleaching.
2Strength
If direct fluorescent dyes are applied to achieve lightening effects, then fiber quality is preserved, but the tenacity against external agents is insufficient
Solution Approach 1:
The invention creates a composite coloring system combining fluorescent dyes with specific molecular structures (formula I) that possess both fluorescent properties and high affinity for keratin fibers. This composite approach integrates the lightening effect of fluorescence with the tenacity of disulfide-containing dyes, achieving both fiber quality preservation and color persistence.
Solution Approach 2:
The invention introduces specific functional groups (disulfide, hydroxy(cyclo)alkylamino) at strategic positions in the dye molecule structure. These local structural modifications enhance the dye's affinity for keratin fibers and its resistance to external agents, while maintaining the fluorescent lightening effect.
3Ease of manufacture
If conventional direct dyes are used for coloring, then the coloring process is simple, but significant lightening effect is not achieved
Solution Approach 1:
The invention changes the optical parameters of the dye molecules by incorporating fluorescent chromophores with specific structures (formula I). This parameter change enables the dyes to absorb UV radiation and emit visible light, producing a lightening effect that conventional non-fluorescent direct dyes cannot achieve, while maintaining procedural simplicity.
4Illumination intensity
If existing fluorescent dyes are applied to dark hair, then lightening effects are obtained, but low tenacity against successive shampoos is observed
Solution Approach 1:
The invention introduces disulfide groups and hydroxy(cyclo)alkylamino units at specific positions in the fluorescent dye structure (formula I). These local structural features create strong interactions with keratin fibers through hydrogen bonding and potential disulfide exchange reactions, significantly enhancing color persistence against shampoos and external agents while maintaining the fluorescent lightening effect.
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 process effectively lightens dark hair without degrading it, maintaining its cosmetic properties and persisting against shampoos and common hair treatments, with the dyes exhibiting satisfactory photostability and chemical stability, allowing for a broader color range and easy stripping.
Implementation Method 1
The invention relates to the coloring of keratin materials using styryl hydroxy(cyclo)alkylamino thiols/disulfide fluorescent dyes
Data Source
AI summary
The invention relates to the coloring of keratinous materials using styryl hydroxy(cyclo)alkylamino thiol/disulfide fluorescent dyes. The invention also relates to a dye composition comprising a styryl hydroxy(cyclo)alkylamino thiol/disulfide fluorescent dye, and a coloring process employing said composition, notably with a lightening effect on keratinous materials such as hair. Furthermore, it relates to novel thiol/disulfide fluorescent dyes and their uses in lightening keratinous materials. This composition provides a particularly long-lasting and visible lightening effect on dark keratinous fibers.