Abstract: Powders having contact biocidal properties comprise a polysaccharide carrying atomic/metallic silver. The preferred polysaccharide is chitin, although other polysaccharides including chitosan, carboxymethyl celluloses and carrageenans can be used. The chitin may be obtained from deproteinated crustacean shells without demineralisation, thus being admixed with calcium carbonate and other naturally occurring minerals present in the shells, and may be enzyme deacetylated. The powders of the invention can be used as biocidal dusting powders, formulated into pastes, gels, hydrogels, creams, foams and aerosol sprays for pharmaceutical applications, or dissolved to form solutions for coating substrates such as skin, fabrics, glass, leather and paper to give a bactericidal surface. A particular application of such a solution is as a protective, post-wash treatment for workwear in a laundering process.

Abstract: In a process for the preparation of an article having a contact biocidal property, there is provided a polymer solution which contains atomic/metallic silver in suspension or complexed with the polymer and/or which contains a silver compound in solution, in suspension or complexed with the polymer. This polymer solution is applied to a substrate by impregnation or surface deposition, thus coating the substrate. Alternatively, it is possible to convert the polymer solution to a fibre, film, powder or foam, effectively forming the article from the polymer solution instead of coating an existing article. In either case, any silver compound present is reduced to atomic/metallic silver, and the resultant article is dried. Chitosan is preferably used as the polymer, although poly(vinyl alcohol) and sodium alginate can also be used. The polymer may be cross-linked at a suitable point in the process to insolubilize it.

Abstract: In a process for the preparation of an article having a contact biocidal property, there is provided a polymer solution which contains atomic/metallic silver in suspension or complexed with the polymer and/or which contains a silver compound in solution, in suspension or complexed with the polymer. This polymer solution is applied to a substrate by impregnation or surface deposition, thus coating the substrate. Alternatively, it is possible to convert the polymer solution to a fibre, film, powder or foam, effectively forming the article from the polymer solution instead of coating an existing article. In either case, any silver compound present is reduced to atomic/metallic silver, and the resultant article is dried.

Abstract: Powders having contact biocidal properties comprise a polysacharide carrying atomic/metallic silver. The preferred polysaccharide is chitin, although other polysaccharides including chitosan, carboxymethyl celluloses and carrageenans can be used. The chitin may be obtained from deproteinated crustacean shells without demineralisation, thus being admixed with calcium carbonate and other naturally occurring minerals present in the shells, and may be enzyme deacetylated. The powders of the invention can be used as biocidal dusting powders, formulated into pastes, gels, hydrogels, creams, foams and aerosol sprays for pharmaceutical applications, or dissolved to form solutions for coating substrates such as skin, fabrics, glass, leather and paper to give a bactericidal surface. A particular application of such a solution is as a protective, post-wash treatment for workwear in a laundering process.

Abstract: A condensation product of chitosan is formed by its reaction with a bisulfite addition compound HOCRR′SO3A wherein: each of R and R′ independently represents a hydrogen atom, or R represents a hydrogen atom and R′ represents an optionally substituted linear or branched saturated or unsaturated hydrocarbon group having up to 10 carbon atoms or an optionally substituted alicyclic, aromatic carbocyclic or heterocyclic ring, or R represents a CH3 group and R′ represents an optionally substituted primary alkyl group, or R and R′ together represent an optionally substituted alicyclic or heterocyclic ring, and A represents an alkali metal or ammonium ion. The condensation product/polymer is an anionic polyelectrolyte and forms stable anionic solutions in water at neutral pH.