Cationizable Polymer Hair Coloration for Gray Coverage at Neutral pH
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Solution Overview
Problem
Oxidative hair dyes cause damage to the hair structure and surface due to their basic pH requirement, leading to brittleness, reduced elasticity, and combability issues, while also posing health risks from ammonia use, and they lack effective gray coverage and color retention.
Innovation Solution
A cosmetic agent containing an oxidation dye precursor and a cationizable copolymer with a basic aminoalkyl side chain, which improves leveling ability and gray coverage, is used in a cosmetic carrier to maintain a neutral pH and reduce hair damage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If oxidative dyes with basic pH are used to achieve long-lasting color retention, then color fastness is improved, but hair structure damage increases leading to brittleness and reduced combability
Solution Approach 1:
The patent changes the pH parameter from basic to neutral by using a cationizable copolymer instead of traditional basic pH agents. This allows the dye to maintain long-lasting color retention while eliminating the harmful effects of basic pH on hair structure, thereby resolving the contradiction between color fastness and hair damage
Solution Approach 2:
The invention uses a composite system combining oxidation dye precursors with a cationizable copolymer. This composite material provides both the color retention properties of oxidative dyes and the hair care benefits of cationic polymers, achieving durable color while minimizing structural damage
2Productivity
If ammonia is used to adjust pH for improved dyeing performance, then coloring efficiency is enhanced, but health risks and unpleasant smell increase
Solution Approach 1:
The patent replaces ammonia with a cationizable copolymer that maintains neutral pH. This substitution eliminates the harmful health risks and unpleasant odor associated with ammonia while preserving effective dyeing performance through the copolymer's color-retaining properties
Solution Approach 2:
The cationizable copolymer acts as an intermediary substance that performs the pH adjustment function traditionally done by ammonia. It mediates between the need for effective dyeing and the avoidance of harmful chemicals, providing a safe and pleasant alternative
3Ease of operation
If traditional hair after-treatment products are used separately to improve fiber condition, then combability and elasticity are enhanced, but the number of application steps and packaging effort increase
Solution Approach 1:
The patent merges the hair dyeing function with hair after-treatment conditioning into a single product. The cationizable copolymer provides both color retention and fiber conditioning benefits simultaneously, eliminating the need for separate after-treatment steps and reducing packaging complexity
4Ease of operation
If direct dyes are used for temporary coloring with natural shades, then ease of application is improved, but color retention deteriorates leading to quick fading
Solution Approach 1:
The invention creates a composite dyeing system that combines the ease of direct dye application with the retention properties of oxidative dyes. The cationizable copolymer enables direct dyes to achieve long-lasting color retention while maintaining simple application procedures
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 agent enhances color retention and gray coverage while minimizing hair damage, providing a safer and more effective hair dyeing experience.
Implementation Method 1
a cationizable copolymer with a basic aminoalkyl side chain, which improves leveling ability and gray coverage
Implementation Method 2
The invention further relates to the use of this agent to improve the color retention of the dye
Implementation Method 3
at least one oxidation dye precursor... The developer components form the actual dyes under the influence of oxidizing agents or atmospheric oxygen
Data Source
AI summary
The object of the invention is an agent for the color and/or permanent shape changing of fibers containing keratin, particularly human hair, comprising at least one oxidation colorant pre-product and at least one non-permanent, ionic co-polymer in a cosmetic carrier, said co-polymer being derived from at least one cationizable monomer of the general formula (I), where R1 and R2 are each hydrogen or a methyl group independently of each other, R3 and R4 are each alkyl groups having 1 to 4 hydrogen atoms independently of each other, Y is a NH group or an oxygen atom, and p is a whole number from 2 to 5. The invention further relates to a method of such agents on fibers containing keratin. The invention also relates to the use of said agent for improving gray coverage, and for controlling the durability of the colorant.