Hydroxypropyl methyl cellulose acetate succinate, method for producing the same, and composition for hot-melt extrusion

Patent metadata

Field	Value
Publication number	US-11767371-B2
Application number	US-202117484405-A
Country	US
Kind code	B2
Filing date	Sep 24, 2021
Priority date	Oct 1, 2020
Publication date	Sep 26, 2023
Grant date	Sep 26, 2023

Abstract

There is provided a method for efficiently produce hydroxypropyl methyl cellulose acetate succinate (HPMCAS) having excellent flowability, where acetic acid in a reaction product mixture subjected to a wash and recovery step can be reduced. More specifically, there is provided a method for producing HPMCAS including an esterification step of esterifying hydroxypropyl methyl cellulose (HPMC) with acetic anhydride and succinic anhydride in acetic acid as a solvent to obtain a reaction product solution containing HPMCAS; a water addition step of adding water to the reaction product solution to obtain a water-added reaction product solution; an acetic acid removal step of removing at least a portion of both the solvent acetic acid and acetic acid derived from the acetic anhydride from the water-added reaction product solution to obtain a mixture having an acetic acid content reduced; and a wash and recovery step of washing the mixture and recovering the HPMCAS.

First claim

The invention claimed is:

1. A method for producing hydroxypropyl methyl cellulose acetate succinate comprising:
an esterification step of esterifying hydroxypropyl methyl cellulose with acetic anhydride and succinic anhydride in acetic acid as a solvent to obtain a reaction product solution containing hydroxypropyl methylcellulose acetate succinate;
a water addition step of adding water to the reaction product solution to obtain a water-added reaction product solution;
an acetic acid removal step of removing at least a portion of both the solvent acetic acid and acetic acid derived from the acetic anhydride from the water-added reaction product solution to obtain a mixture having an acetic acid content reduced; and
a wash and recovery step of washing the mixture and recovering the hydroxypropyl methyl cellulose acetate succinate.

2. The method for producing hydroxypropyl methyl cellulose acetate succinate according to claim 1 , wherein an amount of the acetic acid removed in the acetic acid removal step corresponds to 10.0% or more of the solvent acetic acid.

3. The method for producing hydroxypropyl methyl cellulose acetate succinate according to claim 1 , wherein the acetic acid removal step comprises evaporating the acetic acid by heating and stirring the water-added reaction product solution under a reduced pressure.

4. The method for producing hydroxypropyl methyl cellulose acetate succinate according to claim 2 , wherein the acetic acid removal step comprises evaporating the acetic acid by heating and stirring the water-added reaction product solution under a reduced pressure.

Assignees

• Shinetsu Chemical Co

Inventors

• Miki Akiko
• Kitaguchi Taishi
• Kitamura Akira
• Narita Mitsuo

Classifications

• C08B3/16 Primary

  Preparation of mixed organic cellulose esters {, e.g. cellulose aceto-formate or cellulose aceto-propionate} · CPC title

• B29C48/022

  characterised by the choice of material · CPC title

• B29C48/36

  Means for plasticising or homogenising the moulding material or forcing it through the nozzle or die · CPC title

• C08B13/00 Primary

  Preparation of cellulose ether-esters · CPC title

• C08L1/32

  Cellulose ether-esters · CPC title