Process for producing cellulose derivatives of high bulk density, good flowability and/or dispersibility in cold water as well as low solution color

Patent metadata

Field	Value
Publication number	US-2016244533-A1
Application number	US-201615096704-A
Country	US
Kind code	A1
Filing date	May 4, 2016
Priority date	Sep 25, 2012
Publication date	Aug 25, 2016
Grant date	—

Abstract

A particulate cellulose derivative is obtained in a process of grinding and drying a moist cellulose derivative which comprises the steps of
A) providing a cellulose derivative having a moisture content of from 60 to 95 percent, based on the total weight of the moist cellulose derivative, B) grinding and partially drying the moist cellulose derivative in a gas-swept impact mill; C) contacting the ground and partially dried cellulose derivative with an additional amount of a drying gas outside the gas-swept impact mill; and D) subjecting the cellulose derivative to partial depolymerization after having contacted the cellulose derivative with a drying gas in step C).

The obtained particulate cellulose derivative has a high untapped bulk density, a good flowability and a low color intensity.

First claim

1 .- 8 . (canceled)

9 . A method of improving the flowability and/or the cold water dispersibility of a particulate cellulose derivative comprising the steps of
A) providing a cellulose derivative having a moisture content of from 25 to 95 percent, based on the total weight of the moist cellulose derivative, B) grinding and partially drying the moist cellulose derivative in a gas-swept impact mill wherein the gas fed into the impact mill has a temperature of 100° C. or less; C) contacting the ground and partially dried cellulose derivative with an additional amount of a drying gas outside the gas-swept impact mill, wherein the additional amount of drying gas outside the gas-swept impact mill has a higher temperature than the gas fed into the impact mill; and D) subjecting the cellulose derivative to partial depolymerization after having contacted the cellulose derivative with a drying gas in step C).

10 . A particulate cellulose derivative having
i) an untapped bulk density of at least 370 g/l, ii) a Carr Index of 20 or less; iii) a viscosity of from 1.2 to 200 mPa·s, measured as a 2 weight-% solution in water at 20° C. according to DIN 51562-1:1999-01; and iv) a color of not more than 40 APHA color units, determined as a 2 weight-% solution in water at 20° C. according to ASTM D1209-05 (2011).

11 . The particulate cellulose derivative of claim 10 having a median Equivalent Projected Circle Diameter (EQPC) of at least 50 micrometers.

12 . The particulate cellulose derivative of claim 10 having a color of not more than 35 APHA color units, determined as a 2 weight-% solution in water at 20° C. according to ASTM D1209-05 (2011).

13 . An aqueous composition produced by blending water, the particulate cellulose derivative of claim 10 and one or more optional additives.

14 . A process for the manufacture of capsules comprising the step of contacting the aqueous composition of claim 13 with dipping pins.

15 . A process for coating a dosage form comprising the step of contacting the aqueous composition of claim 13 with the dosage form.

16 . The particulate cellulose derivative of claim 10 being one of an alkyl cellulose, hydroxyalkyl cellulose or hydroxyalkyl alkylcellulose.

17 . The particulate cellulose derivative of claim 10 being hydroxypropyl methylcellulose.

18 . The particulate cellulose derivative of claim 10 having an untapped bulk density of at least 430 g/l.

19 . The particulate cellulose derivative of claim 10 having a Carr Index of 16 or less.

20 . The particulate cellulose derivative of claim 10 having a median LEFI of from 50 to 600 micrometers.

21 . The particulate cellulose derivative of claim 10 having a median LEFI of from 100 to 400 micrometers.

22 . The particulate cellulose derivative of claim 10 having a median Equivalent Projected Circle Diameter (EQPC) of from 100 to 300 micrometers.

Assignees

• Dow Global Technologies Llc

Inventors

• Goerlach-Doht Yvonne M
• Hermanns Juergen
• Hoelzer Bettina

Classifications

• C08J3/124 Primary

  Treatment for improving the free-flowing characteristics · CPC title

• C08B11/193 Primary

  Mixed ethers, i.e. ethers with two or more different etherifying groups · CPC title

• C09D101/26

  Cellulose ethers · CPC title

• C09D101/08

  Cellulose derivatives · CPC title

• C08L1/284

  with hydroxylated hydrocarbon radicals · CPC title