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AssigneeShin-Etsu Chemical Co., Ltd.
InventorsTaishi KITAGUCHI, Shinichi KUROTANI, Tsuyoshi HOSHINO, Akira KITAMURA
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Provided is a method of producing hydroxypropyl methylcellulose acetate succinate powder capable of inhibiting aggregation of particles of the precipitated esterified cellulose ether and reducing produced amount of fine powder to thereby obtain the esterified cellulose ether in high yield. The method of producing hydroxypropyl methylcellulose acetate succinate powder comprises an esterification reaction step, a precipitation step, a washing/recovering step and a drying step, wherein the precipitation step is a step of introducing the reaction solution, obtained in the esterification reaction step, and water into a mixer provided with a rotatable rotor having blades and a perforated plate arranged to surround the rotor in a direction perpendicular to a radial direction of the rotor to allow a suspension, containing precipitated hydroxypropyl methylcellulose acetate succinate particles, to pass through the perforated plate to be discharged therethrough.
A method of producing hydroxypropyl methylcellulose acetate succinate powder comprising the steps of:
A hydroxypropyl methylcellulose acetate succinate powder, wherein an average particle diameter of the hydroxypropyl methylcellulose acetate succinate powder as determined in accordance with a dry sieving test as set forth in JIS Z8815 is 300 μm or more and 1000 μm or less, the powder has a loose bulk density of 0.30 g/mL or less, and a degree of compression of the powder, defined as a ratio of the difference between a tapped bulk density and a loose bulk density relative to the tapped bulk density, is 10% or less.
Dependencies are inferred from the claim text.