Solvent-activated color forming compositions

摘要

Color-forming compositions comprising (i) a solvent absorbing material such as a polymer; (ii) a color-former or chelating agent compounded with the solvent absorbing material; and (iii) a source of metal ions, whereby the metal ions complex with the color former as the solvent absorbing material absorbs the solvent, resulting in a detectable color change of the solvent absorbing material. Both reversible and irreversible versions of these color-forming compositions are provided.