Polymeric Agent for Stable Aqueous Suspensions at Acidic pH
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Solution Overview
Problem
Formulating stable aqueous compositions with suspended particles that maintain homogeneous distribution and clarity over time, particularly at acidic pH levels, is challenging due to phase instability and sedimentation issues.
Innovation Solution
A polymer composed of anionic, nonionic, oxyalkylated, and crosslinking monomers acts as both a thickener and clarifying agent, ensuring homogeneous particle distribution and stability in the continuous phase, even at pH levels less than 7.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If the composition is formulated at acidic pH (below 7), then the composition is more compatible with natural skin pH and preserves active ingredients better, but the continuous phase becomes unstable and rapidly evolves towards phase separation
Solution Approach 1:
The patent uses a specific copolymer with controlled composition parameters (monomer ratios, molecular weight, architecture) to stabilize acidic formulations. The copolymer contains carboxylic acid groups that can be partially neutralized to control charge density, allowing stabilization at pH 3-6 without phase separation
Solution Approach 2:
The invention employs a copolymer combining hydrophilic segments (for water solubility and clarity) with hydrophobic segments (for particle interaction and suspension). This composite structure at molecular level enables simultaneous achievement of clarity, suspension, and acidic pH stability
2Productivity
If particles are suspended in the composition, then the composition provides desired functional and aesthetic properties, but the particles rapidly sediment to the bottom or surface of the container
Solution Approach 1:
The copolymer acts as an intermediary between water and suspended particles, with its amphiphilic structure allowing it to adsorb onto particle surfaces while maintaining solubility in the continuous phase. This mediates particle suspension and prevents sedimentation through steric and electrostatic stabilization
Solution Approach 2:
The copolymer provides localized stabilization at the particle-continuous phase interface, with hydrophobic segments anchoring to particles and hydrophilic segments extending into the aqueous phase. This localized action creates a protective barrier that prevents particle aggregation and sedimentation
3Force
If a thickening agent is added to increase viscosity, then the composition may improve suspension properties, but viscosity increase does not correlate with improved particle suspension ability
Solution Approach 1:
The invention changes from relying on bulk viscosity to using surface-level copolymer adsorption for suspension. The copolymer's molecular structure parameters (hydrophobic/hydrophilic balance, chain length, architecture) are optimized for particle interaction rather than bulk thickening, enabling suspension at low concentrations without significant viscosity increase
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 polymer maintains the clarity and suspension of particles over time, eliminating the need for mixing and ensuring stability during storage, making it suitable for cosmetic and other applications where pH is close to the natural skin pH.
Implementation Method 1
said polymer acts both as a thickener and clarifier of the continuous phase
Implementation Method 2
said polymer acts both as a thickener and clarifier of the continuous phase
Implementation Method 3
allowing a homogeneous distribution of particles in the continuous phase, said compositions remaining stable over time
Data Source
AI summary
The invention relates to an agent for obtaining a stable aqueous solution comprising a polymer made up of: - at least one monomer A of acrylic acid and/or methacrylic acid and/or any one of their salts, - at least one monomer B of alkyl acrylate and/or methacrylate, - at least one monomer C corresponding to the following formula (I): T-[(EO)n'(PO)n''(BO)n'']-Z where: - T represents an end allowing the copolymerization of the monomer C, - [(EO)n(PO)n'(BO)n''] represents a polyalkoxylated chain made up of alkoxylated units, distributed into distributed into block, alternating or statistical units, chosen from among ethyoxylated units EO, propoxylated units PO, and butoxylated units BO, - n, n', n'' representing, independently of one another, 0 or an integer varying from 1 to 150, the sum of n, n' and n'' not being zero, and - Z represents a fatty, linear or branched chain of at least 16 carbon atoms, - at least one cross-linking monomer D.