Crosslinked Polyelectrolyte Foam Stabilization in Cleansing Formulations
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Solution Overview
Problem
Current cleansing formulations for facial and body hygiene often produce unstable, large-bubbled foam, leading to eye irritation and discomfort, and existing thickening agents fail to provide a suitable consistency and pH stability for effective skin cleaning while minimizing foam contact with the eyes.
Innovation Solution
Incorporating a crosslinked anionic polyelectrolyte derived from 2-methyl 2-[(1-oxo 2-propenyl) amino] 1-propanesulfonic acid, partially or totally salified, with N,N-dialkyl acrylamides and specific monomers, into cleansing formulations to achieve a pH range of 4.0 to 6.5, resulting in a stable and fine foam with controlled viscosity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stability of the object's composition
If sodium chloride is used as a thickening agent, then the formulation viscosity increases and consistency is improved, but the foam becomes unstable with large air bubbles causing eye irritation
Solution Approach 1:
The patent changes the chemical composition parameter by replacing sodium chloride with a specific crosslinked anionic polyelectrolyte composed of 2-methyl-2-[(1-oxo-2-propenyl)amino]propanesulfonic acid, N,N-dialkyl acrylamides, and monomers of formula (I). This parameter change transforms the foam structure from large unstable bubbles to fine stable bubbles, eliminating eye irritation while maintaining formulation consistency.
2Stability of the object's composition
If hydrocolloids such as xanthan gum are used as thickening agents, then the formulation consistency is improved and pH stability is maintained, but the texture becomes stringy and adheres too much to skin and packaging
Solution Approach 1:
The patent changes the rheological parameter by using a crosslinked anionic polyelectrolyte with specific molecular structure and crosslinking degree. This produces a non-stringy texture that does not excessively adhere to skin or packaging surfaces, while maintaining pH stability in the range of 4.0 to 6.5, unlike conventional hydrocolloids.
3Stability of the object's composition
If crosslinked anionic polyelectrolytes are used to thicken formulations, then the viscosity increases, but the foam volume becomes too low and bubble size remains insufficiently fine
Solution Approach 1:
The patent uses a composite polyelectrolyte structure combining three types of monomers: 2-methyl-2-[(1-oxo-2-propenyl)amino]propanesulfonic acid (providing charge density), N,N-dialkyl acrylamides (providing hydrophobicity and chain flexibility), and monomers of formula (I) with long alkyl chains (providing micelle formation capability). This composite structure enables simultaneous achievement of high viscosity and fine stable foam with appropriate volume.
4Reliability
If the pH of cleansing formulations is adjusted to match skin pH (4.0-6.5), then skin compatibility is improved, but existing thickening agents fail to provide sufficient foam quality
Solution Approach 1:
The patent identifies that the polyelectrolyte's charge density and hydrophobicity parameters remain effective across the skin-compatible pH range of 4.0 to 6.5. The crosslinked structure maintains structural integrity and foam-generating capability at these pH values, unlike other thickening agents that fail to produce adequate foam quality in this pH range.
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 method generates a stable, fine foam with a viscosity range of 2000 to 30,000 mPa.s, ensuring effective skin cleaning while minimizing eye irritation by maintaining a low volume of foam with small bubble diameters, thus enhancing user comfort and product efficacy.
Implementation Method 1
They give them this consistency
Implementation Method 2
The volume of this foam, its stability, as well as the pleasant sensations it induces, are important parameters
Implementation Method 3
at an optimal dose, it induces the formation of surfactant micelles, which reduce the movements of the fluid and then increase its viscosity
Data Source
AI summary
The invention relates to a method for improving the foaming properties of cleaning compositions for topical use, having a pH of no lower than 4.0 and no higher than 6.5, and including at least one foaming surfactant, said method being characterized in that an effective quantity of a cross-linked anionic polyelectrolyte (P) is incorporated into said cleaning composition for topical use, said cross-linked anionic polyelectrolyte being obtained through the polymerization, in the presence of at least one cross-linking agent, of at least one monomer having a strong acid function, said monomer being 2-methyl 2-[(1-oxo 2-propenyl) amino] 1-propanesulfonic acid, which is partially or completely salified, with at least one neutral monomer selected from the N,N-dialkyl acrylamides, wherein each of the alkyl groups comprises between one and four carbon atoms and at least one monomer of formula (I), in which R is a linear or branched alkyl radical comprising eight to twenty carbon atoms, and n is a number greater than or equal to one and less than or equal to twenty. The invention also relates to novel compositions which contain the polyelectrolyte (P), foaming surfactants, and acid agents selected from among the α-hydroxy acids and β-hydroxy acids, as well as to the use thereof in cosmetics.