Patent ID: 11873351
Assignee: SHIN-ETSU CHEMICAL CO., LTD.
Field: Macromolecular chemistry, polymers (Chemistry)
Classification: CPC C | IPC C

Claim 0:
1. A method for producing hydroxypropyl methyl cellulose phthalate comprising:
an esterification step of reacting hydroxypropyl methyl cellulose with a carboxybenzoylating agent in the presence of an aliphatic carboxylic acid in a kneader reactor equipped with two or more stirring blades rotating around their own axes and orbitally revolving, to obtain a reaction product solution containing hydroxypropyl methyl cellulose phthalate;
a precipitation step of precipitating the hydroxypropyl methyl cellulose phthalate by mixing the reaction product solution with water to obtain a suspension of the precipitated hydroxypropyl methyl cellulose phthalate; and
a washing and recovering step of washing the hydroxypropyl methyl cellulose phthalate in the suspension and recovering the washed hydroxypropyl methyl cellulose phthalate.