Self-Neutralizing Amino Acid Cationic Esters for pH Stabilization
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Solution Overview
Problem
Existing amino acid-based cationic ester compositions tend to produce aqueous solutions with low pH values, which are undesirable in personal care and cosmetic applications that typically require a pH of 4.0 or higher.
Innovation Solution
A self-neutralizing amino acid-based cationic composition is developed, comprising an amino acid-based cationic ester, a nonionic amphiphile, and an anhydrous buffering agent, which, when dissolved or dispersed in water, maintains a pH of greater than 4 without the need for additional pH adjustment.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If amino acid-based cationic ester compositions are used, then cationic charging and emulsification properties are improved, but pH value decreases to unwanted levels
Solution Approach 1:
A buffering agent is introduced as an intermediary substance that mediates between the strongly acidic amino acid ester and the desired pH range. The buffering agent donates base to neutralize excess acid without requiring direct addition of base to the formulation, thus controlling the pH to fall within the desired range while maintaining the cationic charging properties of the amino acid ester.
Solution Approach 2:
The invention changes the chemical parameters of the amino acid ester by modifying the acid used for neutralization. Instead of using strong inorganic acids that create excessively low pH, the invention employs weak organic acids with controlled acid strength, thereby changing the resulting pH parameter to fall within the desired range while preserving the necessary cationic charging and emulsification properties.
2Reliability
If strong organic acids are used to neutralize amino groups, then cationic charging is achieved, but solution pH becomes too low for personal care applications
Solution Approach 1:
The invention converts the harmful effect of strong acid neutralization (excessively low pH) into a beneficial outcome by using the buffering capacity of the amino acid ester itself. The amino acid ester acts as both the cationic charging agent and its own buffer, utilizing its amino group's ability to accept protons to neutralize excess acid and bring the pH into the desired range for personal care applications.
3Temperature
If pH adjustment is performed manually, then desired pH range is achieved, but formulation time increases
Solution Approach 1:
The amino acid ester composition performs self-adjustment of pH through its inherent buffering capacity. The amino acid ester automatically neutralizes excess acid and stabilizes the pH within the desired range without requiring external intervention or manual adjustment by the formulator, thereby eliminating the time-consuming step of manual pH adjustment while ensuring the pH remains within the appropriate range for personal care products.
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 self-neutralizing composition effectively stabilizes the pH of aqueous solutions within the desired range for personal care and cosmetic products, eliminating the need for time-consuming pH adjustments and ensuring product stability and performance.
Implementation Method 1
an anhydrous buffering agent... provides a resultant solution/dispersion having a pH of greater than about 4
Data Source
AI summary
The invention described herein includes a self-neutralizing amino acid-based cationic composition that includes: from 10 wt % to 70 wt % of an amino acid-based cationic ester of formula (I):where R1 is a branched or linear alkyl group having 1 to 10 carbon atoms, R2 is a linear or branched carbon chain having 10 to 50 carbon atoms, where X− represents a conjugate base; from 2 wt % to 25 wt % of an anhydrous buffering agent comprising a salt formed from a strong base and a weak organic acid; and a nonionic amphiphile having 10 to 35 carbon atoms in an amount sufficient to total 100 wt % of the composition. The composition may be in anhydrous solid form and may be a dispersion of particles of the anhydrous buffering agent in a mixture of the amino acid-based cationic ester and the nonionic amphiphile.