| 摘要 |
Secure cards consisting essentially of a card base having an overlying thermally transferred topcoat, with a thermal transfer image in a dye-receptive surface of the card base and the topcoat typically of a polymethyl methacrylate composition, frequently show severe image fading after relative short periods of time when kept and carried in normal PVC pouches. To improve protection against such fading, the present topcoat comprises at least one barrier layer which is formed of a polymer composition having a Tg>70° C., and which is resistant to the formation of microscopic cracks in the topcoat under tensile bending that is insufficient to cause macroscopic permanent deformation.
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