Polymer-Shell Emulsion Drops for Surfactant-Free Stability
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Solution Overview
Problem
Cosmetic emulsions face challenges in achieving kinetically stable, mechanically resistant, and cosmetically appealing formulations without surfactants, particularly in terms of texture and resistance to shearing or fragmentation during industrialization and transport.
Innovation Solution
A stable emulsion of water-in-oil or oil-in-water type is developed, comprising a continuous phase and a dispersed phase with a shell formed by anionic and cationic polymers, where the cationic polymer has specific amine functions, and the fatty phase does not include polydimethylsiloxane, ensuring improved mechanical resistance and coalescence resistance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If surfactants are used to stabilize cosmetic emulsions, then emulsion stability is improved, but user irritation increases
Solution Approach 1:
The invention extracts and eliminates surfactants from the emulsion formulation while maintaining stability through alternative mechanisms. The emulsion is stabilized by the interfacial film formed by the shell material itself (biopolymer or protein) and the specific interfacial conditions, removing the harmful surfactant component entirely.
Solution Approach 2:
The invention introduces an intermediary mechanism - the shell structure formed by biopolymer or protein at the interface between dispersed and continuous phases. This shell acts as a mediator that provides steric and electrostatic stabilization without requiring surfactants, thus maintaining emulsion stability while avoiding user irritation.
2Ease of manufacture
If simple emulsion preparation processes are used, then manufacturing complexity is reduced, but mechanical resistance and coalescence resistance deteriorate
Solution Approach 1:
The invention employs a shell structure formed by biopolymer or protein that encapsulates the dispersed phase droplets. This flexible shell provides mechanical strength and resistance to coalescence while allowing the emulsion to be prepared by simple processes. The shell acts as a protective barrier that maintains droplet integrity during handling and transport.
3Ease of operation
If shell thickness is reduced to improve texture, then cosmetic properties are improved, but mechanical resistance deteriorates
Solution Approach 1:
The invention uses composite shell structures formed by combinations of biopolymers and/or proteins with specific functional groups. These composite materials provide both the thin film characteristics needed for smooth cosmetic texture and the mechanical strength required for resistance to shearing and fragmentation. The synergistic interaction between different polymer components achieves both goals simultaneously.
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 emulsion maintains visual homogeneity and mechanical stability at various temperatures, preventing phase shift and coalescence, resulting in a smooth texture and resistance to shearing, while avoiding surfactant-related irritations.
Implementation Method 1
said drops comprising a shell formed of at least one anionic polymer comprising at least one carboxylic acid function and at least one cationic polymer comprising at least two amine functions
Implementation Method 2
WO/2012/120043 describes a process for forming drops stabilized by biphasic complex coacervation
Data Source
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AI summary
The invention relates to an emulsion comprising a continuous aqueous phase and an oil phase dispersed in the form of drops, or vice versa, said drops comprising a shell formed by at least one anionic polymer having at least one carboxylic acid function and at least one cationic polymer having at least two amine functions, in which the amount of amine functions provided by the cationic polymer in the oil phase is between 0.2 μmoΙ and 10.5 μmoΙ per gram of oil phase.