Hypromellose phthalate and method for producing the same

Patent metadata

Field	Value
Publication number	US-10934369-B2
Application number	US-201916407871-A
Country	US
Kind code	B2
Filing date	May 9, 2019
Priority date	May 11, 2018
Publication date	Mar 2, 2021
Grant date	Mar 2, 2021

Abstract

There is provided a method for producing hypromellose phthalate (HPMCP) which exhibits an excellent solubility when dissolved in a solvent, while suppressing formation of undissolved matter. More specifically, there is provided a method for producing HPMCP, including an esterification step of esterifying hypromellose dissolved in glacial acetic acid with phthalic anhydride in the presence of sodium acetate at a temperature of from 75 to 100° C. to obtain a reaction product solution; a cooling step of cooling the reaction product solution to 70° C. or lower; and a precipitation step of mixing the cooled reaction product solution with water of from 0 to 40° C. to obtain a suspension of precipitated HPMCP.

First claim

The invention claimed is:

1. A method for producing hypromellose phthalate, comprising:
an esterification step of esterifying hypromellose dissolved in glacial acetic acid with phthalic anhydride in the presence of sodium acetate at a temperature of from 75 to 100° C. to obtain a reaction product solution;
a cooling step of cooling the reaction product solution to a temperature of 70° C. or lower; and
a precipitation step of mixing the cooled reaction product solution with water of from 0 to 40° C. to obtain a suspension of precipitated hypromellose phthalate; and further comprising,
between the cooling step and the precipitation step, a step of mixing the cooled reaction product solution with such an amount of water of from 0 to 40° C. as not to cause precipitation of hypromellose phthalate;
wherein no water is added to the reaction product solution until the reaction product solution is cooled to said temperature of 70° C. or lower.

2. The method for producing hypromellose phthalate according to claim 1 , wherein said cooling step comprises cooling the reaction product solution to a temperature of from 40 to 70° C.

3. The method for producing hypromellose phthalate according to claim 1 , wherein, in the precipitation step, a temperature of the reaction product solution after mixed with the water is 55° C. or lower.

4. The method for producing hypromellose phthalate according to claim 2 , wherein, in the precipitation step, a temperature of the reaction product solution after mixed with the water is 55° C. or lower.

Assignees

• Shinetsu Chemical Co

Inventors

• Matsubara Junichi
• Yoshida Mitsuhiro

Classifications

• C08B11/22

  Isolation · CPC title

• C08B11/08 Primary

  with hydroxylated hydrocarbon radicals; Esters, ethers, or acetals thereof · CPC title

• C08B13/00 Primary

  Preparation of cellulose ether-esters · CPC title