Crosslinked Anionic Polyelectrolyte Thickener for Cosmetic Gels
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Solution Overview
Problem
Current synthetic thickening polymers used in cosmetics and pharmaceuticals, particularly in reverse latex form, can cause skin intolerance and are unsuitable for clear gels due to the presence of oil and surfactants, leading to issues like sticky or grainy textures and poor salt resistance in low pH formulations.
Innovation Solution
Development of crosslinked anionic polyelectrolytes from polymerization of 2-methyl 2-[(1-oxo 2-propenyl) amino] 1-propanesulfonic acid with N,N-dimethyl acrylamide and specific monomers, such as tetraethoxylated lauryl methacrylate or eicosaethoxylated stearyl methacrylate, in the presence of a crosslinking agent, which provides enhanced thickening properties and stability across a wide pH range without the drawbacks of traditional polymers.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If reverse latex form polymers are used for thickening, then thickening performance is improved, but skin intolerance and sticky/grainy texture occur due to oil and surfactant presence
Solution Approach 1:
The invention extracts and removes the harmful components (oil and surfactants) from the polymer system by using a water-soluble polymer formulation instead of reverse latex, thereby eliminating skin intolerance and sticky texture while maintaining thickening performance
Solution Approach 2:
The invention changes the chemical composition parameters by selecting specific monomers (acrylic acid, acrylamide, and fatty alkyl methacrylate with controlled ethoxylate groups) that provide water solubility and appropriate thickening properties without the harmful effects of traditional reverse latex components
2Reliability
If traditional terpolymers with fatty alcohols are used, then thickening properties are improved, but unattractive elastic appearance and grainy texture occur
Solution Approach 1:
The invention modifies the polymer structure by controlling the fatty alkyl methacrylate composition (specifically using tetraethoxylated lauryl methacrylate or eicosaethoxylated stearyl methacrylate) to achieve smooth, continuous texture and attractive appearance while maintaining effective thickening properties
Solution Approach 2:
The invention creates a composite polymer system combining three different monomer types (acrylic acid, acrylamide, and fatty alkyl methacrylate) in specific proportions to achieve both thickening performance and desirable sensory properties
3Shape
If low pH formulations are used with some thickeners, then gel transparency is achieved, but salt resistance deteriorates in the long term
Solution Approach 1:
The invention optimizes the polymer composition by incorporating acrylamide units alongside acrylic acid units, creating a balanced structure that maintains both transparency at low pH and long-term salt resistance through enhanced molecular stability
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 new polyelectrolytes offer improved stability to salts, transparent gel formation, and a non-sticky, continuous texture, making them suitable for a wide range of cosmetic and pharmaceutical applications while avoiding skin intolerance issues.
Implementation Method 1
resulting from the polymerization of 2-methyl 2-[(1-oxo 2-propenyl) amino] 1-propanesulfonic acid, partially salified or completely salified, with N,N-dimethyl acrylamide, and at least one monomer of formula (I) in the presence of at least one crosslinking agent
Data Source
AI summary
The invention relates to a branched or crosslinked anionic polyelectrolyte of at least one monomer having a partially- or totally-salified strong acid function, with at least one neutral monomer and at least one monomer having formula (I), wherein: R represents a linear or branched alkyl radical comprising between 8 and twenty carbon atoms, and n represents a number greater than or equal to 1 and less than or equal to twenty. The invention also relates to the use thereof as a thickener in topical compositions.