Process for making antimicrobial articles by reacting chitosan with amino-reactive polymer surfaces
Polymer articles are rendered antimicrobial by a process that includes contacting a chitosan solution with a polymer surface that inherently contains amino-reactive functional groups as polymerized. The process requires no pretreatment with agents such as oxidizing agents or plasma to generate the necessary functional groups at the polymer surface.
1. A polymeric material comprising
a) a polymer that as polymerized, presents a surface that contains amino-reactive functional groups, wherein the amino-reactive functional groups are metal ions, ammonium ions, anhydrides, carboxylic acids, sulfonic acid, isocyanates, epoxides, acid chlorides, enones, and combinations thereof; wherein the polymer is provided in the form of film or yarn, wherein said surface has not been subjected to chemical or physical modification or priming by treatment with caustic, acid or plasma etching prior to contacting the surface with a chitosan solution to form a chitosan coating;
b) a chitosan coating on the surface of the polymer, wherein the chitosan coating is formed by contacting the surface with a chitosan solution such that the chitosan is reacted with said functional groups and then drying the chitosan coating, and wherein the surface of said polymeric material has a chitosan concentration sufficient to reduce microbial growth; and
c) one or more metal salts wherein the metal salt has been applied by dipping, spraying or padding a dilute solution consisting of the salt in water onto the dried chitosan-coated surface of the polymeric material.
2. The polymeric material of claim 1 , wherein the polymer is a homopolymer, random copolymer, block copolymer, graft copolymer, or polymer blend, at least one monomer or comonomer of which contains at least one functional group selected from the group consisting of metal ions, ammonium ion, anhydrides, carboxylic acid or carbonate, sulfonic acid or sulfonate, isocyanates, epoxides, acid chlorides, and enones.
3. The polymeric material of claim 1 , wherein the polymer material comprises an ionomer.
4. The polymeric material of claim 3 , wherein the ionomer is an ionomer of ethylene/acrylic acid copolymer or of ethylene/methacrylic acid copolymer; a perfluorinated sulfonate or carboxylate polymer; a sulfonated polystyrene; a sulfonated ethylene-propylene terpolymer; a sulfonated polyester; or a sulfonated polyamide.
5. The polymeric material of claim 1 , wherein the polymer is a copolymer of ethylene with acrylic acid or methacrylic acid.
6. The polymeric material of claim 1 , wherein the metal salts are selected from water-soluble zinc salt, water-soluble copper salt, water-soluble silver salt, and mixtures thereof.