PURPOSE: To obtain the resin composition by which the shelf life of a product of a definite shelf life can be visually judged by changing its hue, by mixing a thermoplastic resin with a volatile electron-accepting organic compound and a difficultly volatile electron-donating coloring organic compound.
CONSTITUTION: The composition is prepared by melt-mixing a thermoplastic resin with a volatile electron-accepting organic compound and a difficultly volatile electron-donating coloring organic compound. This composition can be heat-processed at a temperature below the heat decomposition temperature of the electron-accepting organic compound or the electron-donating coloring organic compound. The thermoplastic resins to be used may be any one that does not cause the coloration of the electron-donating coloring organic compound and are exemplified by a branched low-density polyethylene and a high-density polyethylene. Examples of the coloring organic compounds used include rhodamine lactams, fluorans and triphenylmethanephthalides. Examples of the electron- accepting organic compounds used include resorcinol, cresol and salicyclic acid.
SHIBATA SEIICHI
NAGAMATSU TATSUHIRO
