Patent ID: 6565768
Filing Date: 2003-05-20
Classification: A61L,C08F,Y10S

Abstract:
A process for preparing a water-swellable hydrophilic polymer, comprising:neutralizing an acidic hydrogel having a degree of neutralization of 0-40 mol % by mixing with a neutralizing agent in a mincer which comprises at least one screw, a rotating blade, a restricted flow zone and a breaker plate, to obtain neutralized and minced hydrogel particles having a final degree of neutralization of 60-85 mol %; wherein said mincer has a power output of from 1000 to 6000 Wh/m3; wherein the acidic hydrogel passes through a zone having an energy dissipation density of from 400 to 800 W/1 of mixing volume; wherein an average residence time of the hydrogel in the mincer is from 5 to 30 seconds; and wherein the breaker plate has an open area of from 20 to 40%.