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HPMCAS WITH LOW SOLUTION VISCOSITY

IP.com Disclosure Number: IPCOM000249776D
Publication Date: 2017-Apr-03
Document File: 1 page(s) / 149K

Publishing Venue

The IP.com Prior Art Database

Abstract

Purified esterified cellulose ether having groups of the formula – C(O) – R – COOH or a combination of aliphatic monovalent acyl groups and groups of the formula –C(O) – R – COOH, wherein R is a divalent aliphatic or aromatic hydrocarbon group, which have a) a degree of neutralization of the groups – C(O) – R – COOH of not more than 0.4, and have b) a solubility in water of at least 1.5 weight percent at 5 °C, based on the total weight of the esterified cellulose ether and water, and c) are purified by washing with water having a temperature of 40-60°C have a low solution viscosity in water.

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HPMCAS WITH LOW SOLUTION VISCOSITY

Purified esterified cellulose ether having groups of the formula – C(O) – R – COOH or a

combination of aliphatic monovalent acyl groups and groups of the formula –C(O) – R – COOH,

wherein R is a divalent aliphatic or aromatic hydrocarbon group, which have a) a degree of

neutralization of the groups – C(O) – R – COOH of not more than 0.4, and have b) a solubility in

water of at least 1.5 weight percent at 5 °C, based on the total weight of the esterified cellulose

ether and water, and c) are purified by washing with water having a temperature of 40-60°C

have a low solution viscosity in water.

Example 1

520 g glacial acetic acid, 200 g HPMC (having a DS (methyl) of 1.9, a MS (hydroxypropoxyl)

of 0.21 and a viscosity of 3 mPa.s, measured as a 2 wt.-% aqueous solution at 20 ºC) and 139 g

sodium acetate were added to the reactor at 85°C. After dissolution of HPMC 11.7g succinic

anhydride and 90g acetic anhydride were added to the reactor. After 3h 2.3 L of deionized water

having 50°C was added to the reactor to precipitate the polymer. The crude HPMCAS was

removed at 50°C from the reactor and being washed several times with water having 50°C. Then

the material was dried at 55°C for 12h.

A 10 wt-% solution of the material from example 1 was prepared by dissolving the material in

deionized water at 2°C under stirring for 12h. The viscosity of the material was 3080 mPa.s at a

shear rate of 0.1 1/s at 20°C measured with a Haake rheometer RS600 and a...