Patent ID: 6048387
Filing Date: 2000-04-11
Classification: B41M,C09K

Abstract:
A reversible thermochromic composition containing (A) a diazarhodamine lactone derivative represented by General Formula (1) below as an electron-donating color-developing organic compound, (B) an electron-accepting compound, and (C) a reaction medium for causing an electron exchange reaction between the diazarhodamine lactone derivative (A) and the electron-accepting compound (B) reversibly at a specified temperature range: ##STR8## where R.sub.1 and R.sub.2 are independently hydrogen, C.sub.1 -C.sub.8 alkyl or hydroxy alkyl, C.sub.2 -C.sub.12 alkoxyalkyl, C.sub.4 -C.sub.11 carboalkoxyalkyl, phenyl, C.sub.7 -C.sub.12 phenylalkyl, or phenyl substituted with chlorine, bromine, or C.sub.1 -C.sub.4 alkyl or alkoxy; R.sub.3 and R.sub.4 are independently hydrogen, C.sub.1 -C.sub.8 alkyl, C.sub.5 -C.sub.7 cycloalkyl or hydroxyalkyl, C.sub.2 -C.sub.12 alkoxyalkyl, C.sub.4 -C.sub.11 carboalkoxyalkyl, or C.sub.7 -C.sub.12 phenylalkyl; R.sub.1 and R.sub.2, and R.sub.3 and R.sub.4 may form together a ring; R.sub.5 is C.sub.1 -C.sub.3 alkyl, C.sub.1 -C.sub.4 alkoxy, phenyl, or phenyl substituted with chlorine, bromine, or C.sub.1 -C.sub.4 alkyl or alkoxy; X and Y are independently chlorine, or C.sub.1 -C.sub.3 alkyl, hydroxyalkyl, or halogenalkyl; m is an integer of 0 to 3; and n is an integer of 0 to 4.