Patent ID: 7790217

Claim:
A method of imparting non-leachable antimicrobial properties to a substrate consisting essentially of, in sequence, the steps of: a) providing a substrate for use in textiles, medical applications, filters, absorbent materials, or packaging materials, comprised in whole or in part of a cellulosic material, b) treating the substrate by applying an aqueous solution of an antimicrobial cationic polyelectrolyte to the substrate comprised in whole or in part of a cellulosic material wherein the antimicrobial cationic polyelectrolyte has an average degree of polymerization of at least 3, and an excess cationic charge density of at least 1 mole per 25,000 grams; wherein the solution concentration of the antimicrobial cationic polyelectrolyte is at least 0.01 weight percent, c) thoroughly drying the treated substrate, d) rinsing, washing, or extracting to remove any leachable unbonded portion of said antimicrobial cationic polyelectrolyte, and e) performing an assay to verify that non-leachable antimicrobial properties have been imparted to said substrate, whereby non-leachable bonding is effected between at least a portion of the antimicrobial cationic polyelectrolyte and the substrate comprised in whole or in part of a cellulosic material.