Cyclic Mercapto Hair Processing Agent for Neutral pH Perming
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Solution Overview
Problem
Conventional hair processing agents for permanent waving at neutral to weakly acidic pH ranges face issues such as skin irritation, unsatisfactory perming performance, and unpleasant odors, with existing compounds like monoglycerol esters of thioglycolic acid, mercaptocarboxylic acid amides, and cysteamines having limitations in stability and effectiveness.
Innovation Solution
A hair processing agent containing a specific cyclic mercapto compound, which improves stability and perming performance by being used in combination with surfactants and perfumes, allowing for effective permanent waving at neutral to weakly acidic pH ranges while minimizing skin irritation and odor issues.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional keratin reducing substances (thioglycolic acid, cysteine, acetylcysteine) are used at alkaline pH (pH 9.5), then perming performance is improved, but skin and hair damage occurs
Solution Approach 1:
The invention changes the pH parameter from alkaline (pH 9.5) to neutral or weakly acidic range (pH 3-7.5), allowing the use of gentler reducing substances that do not cause skin and hair damage while maintaining perming effectiveness through the discovery of novel cyclic mercapto compounds
2Object-affected harmful factors
If cyclic mercapto compounds are used in neutral to weakly acidic pH range, then skin irritation is reduced, but perming performance becomes insufficient
Solution Approach 1:
The invention uses composite formulations combining cyclic mercapto compounds with other reducing substances (such as thioglycolic acid esters, cysteamines, or mercaptocarboxylic acid amides) to achieve synergistic effects that provide both gentle pH compatibility and sufficient perming performance
Solution Approach 2:
The invention optimizes concentration parameters of cyclic mercapto compounds in the formulation to enhance their perming effectiveness at neutral to weakly acidic pH while maintaining low skin irritation
3Reliability
If excessive amounts of reducing substances are used to ensure perming performance at neutral pH, then perming effectiveness is improved, but persistent odor and skin damage occur
Solution Approach 1:
The invention optimizes the concentration parameter of reducing substances to achieve effective perming at lower levels, and combines multiple reducing substances with different mechanisms to enhance effectiveness without increasing total concentration, thereby avoiding persistent odor and skin damage
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 cyclic mercapto compound-based hair processing agent provides enhanced stability and perming performance over a wide pH range, reducing skin irritation and odor, and maintaining performance over time without discoloration or precipitation.
Implementation Method 1
permanent waves are created through two steps, i.e., reductive splitting of cystine (disulfide) bonds of hair by the action of a reducing agent
Implementation Method 2
subsequent neutralization or fixing with an oxidizing agent, whereby the cystine bonds are restored
Implementation Method 3
when the hair processing agent contains water, the cyclic mercapto compound is hydrolyzed and consequently the concentration of the cyclic mercapto compound in the agent is reduced with time
Data Source
AI summary
Provided are hair processing agents capable of permanent waving hair even at a neutral to weakly acidic pH range that causes less irritation to the skin, and hair processing agents in which an unpleasant odor is masked. Hair processing agents contain at least one compound represented by the formula (2). Hair processing agents contain a compound of the formula (2) and at least one compound (ii) selected from thioglycolic acid, thiolactic acid, cysteine, acetylcysteine, cysteamine, acylcysteamine, salts thereof and ester derivatives thereof. Hair processing agents contain a compound of the formula (2), a surfactant and water, and are emulsified. Hair processing agents contain a compound of the formula (2) and a specific perfume. wherein X is a structure selected from —O—, —S—, —NH— and —NR1—; R1 is an alkyl group of 1 to 6 carbon atoms; Y is an oxygen atom or a sulfur atom; in the formula (1), Z is a divalent organic residue having at least one mercapto group; in the formula (2), R is a divalent organic residue optionally having a mercapto group; and R2 is a hydrogen atom or an alkyl group of 1 to 6 carbon atoms.