US Patent 7745517 Polyvinyl alcohol films with improved resistance to oxidizing chemicals

A water-soluble film which comprises a saceharide component and a vinyl alcohol resin component, where the vinyl alcohol resin may include functional comonomer units such as sulfonic acid functional groups or salts thereof. Preferred are polyvinyl alcohol/2-methylacrylamido-2 methyl propane sulfonic acid resins (PVOH/AMPS) which may be purchased commercially with relatively higher or relatively lower characteristic viscosity. The films exhibit superior resistance to aggressive oxidizing chemicals and remain soluble in water after prolonged exposure thereto. The films are particularly useful for unit-dose packaging of chlorine-containing pool chemicals, such as trichloroisocyanuric acid.