Thermographic recording system
AssigneeBard Laboratories, Inc.
InventorAlbert P. Yundt
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Abstract
Thermorecording sheet, thermorecording method and method of manufacture of a thermally responsive recording paper comprising a reversibly reduced cyclic polyketo compound, such as hydrindantin and an N,N' polythiodiamine having a sulfur chain length of at least two sulfur atoms.
Claims13
A thermally responsive recording sheet comprising a substrate and a thermally responsive coating on the substrate comprising, in a reversibly reduced form, a cyclic polyketo compound, color reactive with amines, and an N,N' polythiodiamine.
In a method for recording on a thermally responsive sheet employing selective thermal activation of an amine-polyketo color compound system to produce a visible mark, the improvement comprising conducting, upon said thermal activation, a redox reaction between a cyclic polyketo compound in reversibly reduced form and an N,N' polythiodiamine to reductively decompose said N,N' polythiodiamine and to oxidize said reduced polyketo compound to provide, respectively, cyclic polyketo compound and reactive amine components of an amine-cyclic polyketo color compound system responsive to said thermal activation.
A method of manufacturing a thermally responsive recording paper, comprising, providing an aqueous coating dispersion of finely divided hydrindantin and finely divided N,N' polythiodiamine in an aqueous solution or dispersion of a suitable water soluble or dispersable binder material, coating a base paper substrate with said aqueous coating dispersion, and drying said coated paper.
Dependencies are inferred from the claim text.