Patent ID: 7012139
Filing Date: 2006-03-14
Classification: C08B,C08L,C09J

Abstract:
1. A process for preparing cellulose ethers having delayed dissolution in water, comprising: (a) treating a moist cellulose ether with a solution comprising a dialdehyde; (b) adding an aqueous salt solution to the moist cellulose ether, such that said cellulose ether has a pH of from 6.0 to 8.0, the aqueous salt addition being performed at least one of, (i) prior to step (a), (ii) concurrently with step (a), and (iii) subsequent to step (a); and (c) drying and comminuting the treated cellulose ether of step (b), wherein said aqueous salt of step (b) comprises at least two salts, one salt being a weak acid having a pka of from 5.5. to 8.5, and the other salt being the salt of a weak acid having a pka of from 5.5. to 8.5.