Stable microdispersions and microgels based on acrylic polymers, method for obtaining them and compositions, particularly cosmetic compositions, containing them
First Claim
1. In a method of preparing a stable microdispersion of particles of acrylic polymers in an organic solvent in the presence of a stabilizer the improvement comprising:
- forming said acrylic polymer by a free-radical polymerization of at least one acrylic monomer in the presence of a block copolymer as said stabilizer, wherein said block copolymer is a copolymer of polymethyl methacrylate (PMMA) and polytert-butyl acrylate (PtBuA) and said solvent solubilizes said PtBuA chain of said copolymer and precipitates both said PMMA chain of said copolymer and said acrylic polymer.
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Abstract
The invention relates to a process for the preparation of a stable microdispersion of particles comprised of acrylic polymers in an organic solvent used as reaction medium in the presence of a stabilizing agent comprised of a block copolymer, characterized in that said acrylic polymer is obtained by radical polymerization of at least one acrylic monomer in the presence of a block copolymer based on polymethyl methacrylate (PMMA) and polytert-butyl acrylate (PtBuA). It also relates to microdispersions which may be obtained by said process as well as to microgels produced from said microdispersions and compositions, particularly cosmetic compositions such as nail varnish.
65 Citations
24 Claims
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1. In a method of preparing a stable microdispersion of particles of acrylic polymers in an organic solvent in the presence of a stabilizer the improvement comprising:
- forming said acrylic polymer by a free-radical polymerization of at least one acrylic monomer in the presence of a block copolymer as said stabilizer, wherein said block copolymer is a copolymer of polymethyl methacrylate (PMMA) and polytert-butyl acrylate (PtBuA) and said solvent solubilizes said PtBuA chain of said copolymer and precipitates both said PMMA chain of said copolymer and said acrylic polymer.
- View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 20, 23)
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16. A microgel made by a process comprising the steps of:
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(a) forming a stable microdispersion of particles of acrylic polymers in an organic solvent wherein said acrylic polymer is formed by a free-radical polymerization of at least one acrylic monomer in the presence of a block copolymer, said block copolymer being a copolymer of polymethyl methacrylate (PMMA) and polytert-butyl acrylate (PtBuA); (b) drying or concentrating said stable microdispersion of particles, and then transferring said dried or concentrated stable microdispersion of particles to a solvent for PMMA to form a microgel; and (c) recovering said microgel. - View Dependent Claims (17, 18, 19, 21, 22, 24)
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Specification