Invention Grant
US5024987A Recording material 失效
录音材料

Recording material
Abstract:
Pressure-sensitive reactive recording material containinga) as the color-forming agent, a tetraindolylheptamethine ether or alcohol of the formulae I/1, I/2, I/3 or I/4 ##STR1## b) and, as the color developer, the salt of a polyvalent metal and an aromatic carboxylic acid having at least 10 carbon atoms, of the formula (II) ##STR2## wherein A, B, D and E denote ##STR3## and the other radicals have the meanings given in the description, produces light-stable copies which can also be read by machines (OCR).
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