| 摘要 |
Heat-sensitive compositions which rapidly develop color upon heating and rapidly discharge their color upon cooling, comprising an intimate mixture of a 3,3-bis (p-aminophenyl) phthalide and an organic acid. The color-producing and color-discharging cycle may be reproduced many times without noticeable change in response. The novel compositions of the invention are useful as temperature indicators, thermal display media, safety papers and validation devices.
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