Patent ID: 9115217
Filing Date: 2015-08-25
Classification: C08B

Abstract:
1. A dry or slurry process to prepare phosphate-crosslinked cellulose ethers from a cellulose starting material comprising the steps of adding an alkalizing agent to the cellulose starting material to achieve mercerization, adding an etherifying agent to the reaction mixture to achieve etherification of the cellulose, and adding a crosslinking agent to the reaction mixture to achieve crosslinking of the cellulose, wherein at least part of the alkalizing agent is added to the cellulose starting material before the etherification and/or crosslinking reactions take place to obtain alkalized cellulose; the crosslinking agent and the etherifying agent are added one after the other in random order or simultaneously; the crosslinking agent is an alkali metal trimetaphosphate; and the crosslinking and etherification steps are performed at an elevated temperature of between 20 and 95° C. wherein the crosslinking step is carried out at an alkaline pH of higher than 7; and wherein the phosphate-crosslinked cellulose ethers prepared by said dry or slurry process are soluble in water.