Patent ID: 8580952

Claim:
A method for preparing glyoxal free purified cationic polygalactomannan comprising: reacting a polygalactomannan flour, a nonionically derivatized polygalactomannan flour or a mixture thereof with a cationising reagent to form a first composition including a cationic polygalactomannan; adjusting the pH of the first composition to be from about 4 to about 6; cross-linking the cationic polygalactomannan by reacting the cationic polygalactomannan with glyoxal, filtering and water washing the cationic polygalactomannan to produce a glyoxalated purified cationic polygalactomannan containing not more than 70% by weight of water; introducing a buffering agent to the glyoxalated purified cationic polygalactomannan to regulate the pH of the glyoxalated purified cationic polygalactomannan to from 8.0 to about 9.5, when measured at 1% (dry matter) in water; and removing water from the glyoxalated purified cationic polygalactomannan to produce glyoxal free purified cationic polygalactomannan in powder form; wherein the glyoxalated purified cationic polygalactomannan has a cationic DS of from about 0.01 to about 1.