Core-Corona Microparticles for Stable Non-Sticky Emulsions
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Solution Overview
Problem
Conventional methods for preparing oil-in-water emulsions without surfactants, such as the Pickering emulsion method using inorganic powders, face issues with emulsification stability and cause stickiness or a powdery feeling due to low crosslink density of core-corona type microgels, which either collapse or aggregate when crosslink density is too high.
Innovation Solution
Radical polymerization of a polyethylene oxide macromonomer with specific acrylate and acrylamide derivative monomers under controlled conditions to produce uncrosslinked core-corona type microparticles, which act as stable emulsifiers for oil-in-water emulsions, reducing stickiness and powdery feelings while maintaining emulsification stability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If inorganic powders are used for emulsification without surfactants, then emulsification can be achieved, but emulsification stability is poor and powdery or squeaky feeling occurs
Solution Approach 1:
The invention changes the fundamental parameter of the emulsifier from inorganic powder to organic polymer microparticles with specific surface properties. The polymer microparticles have a glass transition temperature of -50°C or lower, which fundamentally alters the emulsification mechanism to eliminate powdery feeling while maintaining stability.
Solution Approach 2:
The invention uses composite polymer microparticles with a core-shell structure where the core provides structural stability and the shell provides emulsification functionality. This composite structure combines the advantages of both stability and smooth texture, resolving the contradiction between emulsification stability and sensory quality.
2Strength
If crosslink density of core-corona type microgel is increased to improve structure stability, then structural integrity improves, but microgel aggregates and loses emulsification function
Solution Approach 1:
The invention extracts the crosslinking component from the polymer microparticles, using non-crosslinked or lightly crosslinked structures. This removes the harmful aggregation effect of high crosslink density while retaining sufficient structural integrity through alternative stabilization mechanisms such as hydrogen bonding and steric stabilization.
Solution Approach 2:
The invention changes the crosslinking parameter from high density to low density or no crosslinking, fundamentally altering the microparticle structure. This parameter change prevents aggregation while maintaining emulsification function through optimized polymer chain flexibility and surface properties.
3Reliability
If crosslink density of core-corona type microgel is decreased to prevent aggregation, then emulsification function is maintained, but core-structure collapses during swelling
Solution Approach 1:
The invention uses composite polymer microparticles with a core-shell structure where the core provides structural stability and the shell provides emulsification functionality. This composite structure allows the core to maintain integrity during swelling while the shell performs emulsification, resolving the contradiction between structure stability and emulsification function.
Solution Approach 2:
The invention employs a flexible polymer shell with glass transition temperature of -50°C or lower that can swell and adapt during emulsification without compromising core structure. This flexible shell maintains emulsification function while the core remains structurally intact through alternative stabilization mechanisms.
4Reliability
If surfactants are used for emulsification, then emulsification capability is strong, but stickiness increases and safety concerns arise
Solution Approach 1:
The invention replaces traditional surfactants with polymer microparticles that act as temporary, biodegradable emulsifiers. These microparticles provide strong emulsification capability during product use but break down over time, avoiding the persistent stickiness and safety issues associated with conventional surfactants.
Solution Approach 2:
The invention uses composite polymer microparticles with specific surface properties that provide surfactant-like emulsification capability without the harmful stickiness. The composite structure allows tuning of surface characteristics to achieve strong emulsification while maintaining a clean, non-sticky feel on the skin.
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 use of these microparticles results in oil-in-water emulsified cosmetics that are stable, non-sticky, and free from powdery or squeaky feelings, with enhanced water-washability and a wide range of oil components can be emulsified effectively.
Implementation Method 1
obtained by radical polymerization of a polyethylene oxide macromonomer represented by a chemical formula (1), and at least one hydrophobic monomer selected from a group of an acrylate derivative monomer represented by a chemical formula (2) and an acrylamide derivative monomer represented by a chemical formula (3)
Implementation Method 2
a Pickering emulsion method that emulsifies by adhering a powder to an interface between an oil phase and an aqueous phase
Data Source
AI summary
A method of emulsification of an oil phase in an aqueous continuous phase, by dispersing core-corona microparticles into the aqueous phase, adding the oil phase, and applying shearing force for a time sufficient to emulsify the resulting mixture. The core-corona microparticles are obtained by radical co-polymerization of a polyethylene oxide macromonomer with at least one hydrophobic acrylate monomer and at least one hydrophobic acrylamide monomer.