Limited coalescence process
First Claim
1. In a limited coalescence method of making polymer particles of controlled size, which method comprises forming an aqueous suspension of polymer droplets, such droplets being immiscible with the aqueous suspension medium and having a layer of particulate suspension stabilizer on their surfaces which limits coalescence between droplets, forming solid particles from the droplets and separating the polymer particles having a layer of particulate suspension stabilizer on their surfaces from the aqueous suspension medium, the improvement comprising (a) controlling the coalescence between the droplets to provide polymer particles having an average particle size of not more than 3 μ
- m, (b) reslurry washing the separated polymer particles by dispersing them in an organic liquid diluent that is miscible with the aqueous suspension medium and is a nonsolvent for the polymer particles, and (c) separating the polymer particles from the diluent to thereby substantially avoid agglomeration between the polymer particles upon drying.
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Accused Products
Abstract
A limited coalescence method of making polymer particles having an average particle size of 3 μm or less comprising dispersing the polymer particles in an organic liquid diluent after they are separated from the aqueous suspension medium in which they are prepared, to thereby eliminate or substantially avoid agglomeration between the polymer particles upon drying.
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Citations
16 Claims
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1. In a limited coalescence method of making polymer particles of controlled size, which method comprises forming an aqueous suspension of polymer droplets, such droplets being immiscible with the aqueous suspension medium and having a layer of particulate suspension stabilizer on their surfaces which limits coalescence between droplets, forming solid particles from the droplets and separating the polymer particles having a layer of particulate suspension stabilizer on their surfaces from the aqueous suspension medium, the improvement comprising (a) controlling the coalescence between the droplets to provide polymer particles having an average particle size of not more than 3 μ
- m, (b) reslurry washing the separated polymer particles by dispersing them in an organic liquid diluent that is miscible with the aqueous suspension medium and is a nonsolvent for the polymer particles, and (c) separating the polymer particles from the diluent to thereby substantially avoid agglomeration between the polymer particles upon drying.
- View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16)
Specification