Process of preparing a high molecular weight esterified cellulose ether
US-2018105607-A1 · Apr 19, 2018 · US
Hypromellose acetate succinate and method for producing the same
US10888525B2 · US · B2
| Field | Value |
|---|---|
| Publication number | US-10888525-B2 |
| Application number | US-201715797876-A |
| Country | US |
| Kind code | B2 |
| Filing date | Oct 30, 2017 |
| Priority date | Nov 2, 2016 |
| Publication date | Jan 12, 2021 |
| Grant date | Jan 12, 2021 |
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Abstract
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There are provided HPMCAS (hypromellose acetate succinate) having such a property that a solution of the HPMCAS in a solvent has a controlled viscosity; and a method for producing the HPMCAS. More specifically, provided are HPMCAS having such property that a solution of 10 parts by weight of the HPMCAS in 100 parts by weight of a mixed solvent having a weight ratio of methylene chloride to methanol of 1:1 has a viscosity at 20° C. of 135 mPa·s or less; and a method for producing the HPMCAS including an esterification step of adding acetic anhydride and succinic anhydride to a solution of hypromellose in glacial acetic acid in the presence of sodium acetate to obtain a reaction product mixture, wherein the succinic anhydride is added intermittently, and a precipitation step of mixing the reaction product mixture with water to precipitate the HPMCAS.
First claim
Opening claim text (preview).
The invention claimed is: 1. A method for producing hypromellose acetate succinate, the method comprising: an esterification step of adding acetic anhydride and succinic anhydride to a solution of hypromellose in glacial acetic acid in the presence of sodium acetate to obtain a reaction product mixture, wherein the succinic anhydride is added intermittently; and a precipitation step of mixing the reaction product mixture with water to precipitate the hypromellose acetate succinate, wherein an amount of the acetic anhydride is 0.4 to 1.3 mol relative to 1 mol of the hypromellose, and wherein a solution of 10 parts by weight of the obtained hypromellose acetate succinate in 100 parts by weight of a mixed solvent having a weight ratio of methylene chloride to methanol of 1:1 has a viscosity at 20° C. of 135 mPa.s or less. 2. The method for producing the hypromellose acetate succinate according to claim 1 , wherein during a period when the succinic anhydride is added, an average addition rate of the succinic anhydride is 0.0020 to 0.2000 mol/min. 3. The method for producing the hypromellose acetate succinate according to claim 1 , wherein the succinic anhydride is added at least two times, wherein the interval between each addition is 4 minutes or more. 4. The method for producing the hypromellose acetate succinate according to claim 1 , wherein an amount of the glacial acetic acid is 1.2 to 2.5 times the weight of the hypromellose.
Assignees
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Classifications
- C08B13/00Primary
Preparation of cellulose ether-esters · CPC title
Cellulose; Cellulose derivatives, e.g. phthalate or acetate succinate esters of hydroxypropyl methylcellulose · CPC title
Cellulose; Derivatives thereof · CPC title
Isoalloxazines, e.g. riboflavins, vitamin B2 · CPC title
- A61K9/2866Primary
Cellulose; Cellulose derivatives, e.g. hydroxypropyl methylcellulose · CPC title
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- What does patent US10888525B2 cover?
- There are provided HPMCAS (hypromellose acetate succinate) having such a property that a solution of the HPMCAS in a solvent has a controlled viscosity; and a method for producing the HPMCAS. More specifically, provided are HPMCAS having such property that a solution of 10 parts by weight of the HPMCAS in 100 parts by weight of a mixed solvent having a weight ratio of methylene chloride to meth…
- Who is the assignee on this patent?
- Shinetsu Chemical Co
- What technology area does this patent fall under?
- Primary CPC classification C08B13/00. Mapped technology areas include Chemistry & Metallurgy.
- When was this patent published?
- Publication date Tue Jan 12 2021 00:00:00 GMT+0000 (Coordinated Universal Time) (B2). Legal status and post-grant events are not shown on this page.
- What related patents are in patentsdb?
- We list 2 related publications on this page (citations in our corpus or others sharing the same primary CPC).