Acrylic Polymer Dispersion Stabilized with Silicone Macromonomer
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Solution Overview
Problem
Existing cosmetic dispersions of acrylic polymers in hydrocarbon-based oils face issues with viscosity, manufacturing complexity, and compatibility with silicone oils, leading to formulation difficulties and suboptimal cosmetic properties such as gloss and oil resistance.
Innovation Solution
A dispersion of C1-C4 alkyl (meth)acrylate polymer particles stabilized with a C8-C22 alkyl acrylate polymer and a silicone macromonomer in a hydrocarbon-based oil, which is easy to manufacture and provides good stability, gloss, and compatibility with silicone oils.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If the solids (polymer+stabilizer) content exceeds 25% by weight in hydrocarbon-based oil dispersions, then the polymer film-forming capability is improved, but the dispersion viscosity becomes too high causing formulation difficulties
Solution Approach 1:
The patent changes the chemical composition parameters of the stabilizer by incorporating silicone macromonomer units with specific molecular weights (1,000 to 100,000 Da) and controlled amounts (0.1-20 mol%). This parameter modification allows achieving >25% solids content while maintaining acceptable viscosity through altered intermolecular interactions and steric effects provided by the silicone segments.
Solution Approach 2:
The stabilizer is designed as a composite block copolymer containing both organic segments (from acrylic monomers like methyl acrylate, ethyl acrylate, isobornyl acrylate) and inorganic silicone segments (from polydimethylsiloxane macromonomer units). This composite structure combines the solubility and film-forming properties of organic polymers with the low surface energy and viscosity-reducing properties of silicone, enabling high solids content dispersions that remain formulation-friendly.
2Ease of manufacture
If conventional stabilizers are used in acrylic polymer dispersions, then the dispersion can be manufactured, but compatibility with silicone oils is poor leading to phase separation
Solution Approach 1:
The stabilizer incorporates polydimethylsiloxane macromonomer units that are chemically homogeneous with added silicone oils in the formulation. This structural homogeneity between the stabilizer's silicone segments and the formulation's silicone oil components prevents phase separation by ensuring compatible intermolecular forces and solubility parameters throughout the system.
Solution Approach 2:
The silicone-containing stabilizer acts as an intermediary component that bridges the organic polymer particles and the silicone oil phase. The stabilizer's dual-nature structure (organic acrylic segments + inorganic silicone segments) allows it to interact with both phases, preventing phase separation by mediating the interface between incompatible components.
3Manufacturing precision
If reversible chain-transfer controlled radical polymerization is used to prepare stabilizing polymer, then the polymerization can be controlled, but the method requires large number of intermediate purification steps making it difficult to perform on industrial scale
Solution Approach 1:
The patent employs a conventional free-radical polymerization method followed by simple filtration to remove the water-soluble initiator and byproducts, rather than using complex controlled polymerization techniques. This approach accepts less precise molecular weight control in exchange for dramatically simplified processing and elimination of multiple purification steps, making the process economically viable for industrial production.
4Ease of manufacture
If dispersions of acrylic polymers in isododecane are used, then the dispersion can be formulated, but problems of compatibility with silicone oils occur giving rise to phase separation
Solution Approach 1:
The patent modifies the stabilizer's chemical composition by incorporating silicone macromonomer units, which changes the surface energy and solubility parameters of the stabilizer. This parameter change enables the stabilizer to compatibilize the acrylic polymer particles with silicone oil phases, preventing phase separation while maintaining formulation ease.
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 dispersion achieves stable cosmetic properties, including good gloss and resistance to oils, while being easy to produce and compatible with silicone oils, thus overcoming the limitations of existing technologies.
Implementation Method 1
stabilized with a stabilizer based on a C8-C22 alkyl acrylate polymer, the polymer and/or the stabilizer comprising a particular silicone macromonomer
Implementation Method 2
the stabilizer and/or the polymer of the particles comprising at least the silicone macromonomer (I)... good compatibility with silicone oils
Implementation Method 3
The presence of the silicone macromonomer (I) in the stabilizer and/or the polymer of the particles makes it possible to obtain a polymer dispersion that is stable
Data Source
AI summary
The invention relates to a dispersion of polymer particles stabilized with a stabilizer in a nonaqueous medium containing at least one hydrocarbon-based oil, the polymer of the particles being a C1-C4 alkyl (meth)acrylate polymer; the stabilizer being a C1-C4 alkyl (meth)acrylate polymer and optionally of a silicone macromonomer (I):the stabilizer being a polymer comprising from 50% to 100% by weight, relative to the total weight of the stabilizer, of C8-C22 alkyl acrylate, from 0 to 50% by weight of C1-C4 alkyl (meth)acrylate and optionally silicone macromonomer (I).The invention also relates to the composition comprising said dispersion of polymer particles.Cosmetic use for caring for and making up keratin materials.