| abstract |
An ink composition as a steam sterilizing indicator for use in ink jet printing which comprises a salt of a cyanine dyestuff with phenol resins in amounts of 0.1-5% by weight as the cyanine dyestuff and in amounts of 0.2-30% by weight as the phenol resins, dissolved in organic solvents in amounts of 70-96% by weight based on the ink composition. The ink composition may further contain at least one of alkali metal salts, resins containing carboxyl groups therein, aliphatic carboxylic acids, anticorrosion agents, nonionic surfactants and dyestuffs which are unchanged in color under sterilizing conditions. The ink composition is discolored or changes in color under steam sterilization conditions. |