PROBLEM TO BE SOLVED: To provide a barrier material which protects an active ingredient and a useful chemical in a water-based system, and induces discharging such a chemical into an environment for use, and is prepared of a multi-stage polymer, and to provide a device. SOLUTION: This trigger response composition is stable and insoluble in the water-based system in a relatively high ion strength, and comprises at least one polymer electrolyte exhibiting at least one chemical/physical response selected from dispersion, degradation, dissolution, instabilization, swelling, deformation, softening, fluidization and combinations thereof by changing at least one ion strength to the water-based system and is brought into contact with the water-based system. Here, the polymer electrolyte comprises (a) 70-99 wt.% alkali-soluble/swelling emulsion polymer, and 1-30 wt.% crosslinked alkali-soluble/swelling emulsion polymer or non-alkali soluble/swelling emulsion polymer. COPYRIGHT: (C)2004,JPO&NCIPI
