| 摘要 |
Binderless ink compositions suitable for use in jet printing operations on polymeric resin surfaces to form images which are highly resistant to abrasion and to steam pasteurization or sterilization conditions by penetration of the colorant into the sub-surface structure of the resin, are provided. The ink compositions are thermotropic, i.e. they change color in the presence of water or steam at elevated temperature and are useful as sterilization or pasteurization indicators. The preferred inks comprise either (1) a colorant which reacts under the sterilization conditions or (2) a combination of colorants one of which is extractible under sterilization conditions; a water and alcohol solvent system; a surfactant; an aliphatic or cyclic ketone, aldehyde, acetal, ether or ester and, optionally, an aliphatic hydrocarbon of 8-12 carbons.
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