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AssigneeHakkol Chemical Co., Ltd.
InventorsShigekazu Matsumoto, Takao Yanagisawa, Shigehiro Matsumoto, Kunio Shimabukuro
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A polyazo compound capable of effectively absorbing near-infrared rays, which can be produced from readily available raw materials is provided, which comprises at least one --OH group or at least one group derived from --OH group at p-position of the azo group in the molecule of the polyazo compound. This compound can be produced by diazotizing a substituted or nonsubstituted aromatic monocyclic or polycyclic compound or heterocyclic compound, each having a diazotizable primary amino group, and successively coupling the resulting diazo component with an azo component having a diazotizable primary amino group, the last azo component being such that --OH group or a group derived from --OH group be present at p-position to the azo group resulting from the azo component.
A near-infrared ray absorbing polyazo compound comprising at least one --OH group or at least one group derived from --OH group, at p-position of an azo group, bonded to an aromatic polycyclic ring in the molecule of the polyazo compound and having an absorption maxima .lambda..sub.max measured in dimethylformamide falling within the range of from 700 to 1,000 nm.
A process for the production of a near-infrared ray absorbing polyazo compound comprising at least one --OH group or at least one group derived from --OH group, at p-position of an azo group, bonded to an aromatic polycyclic ring in the molecule of the polyazo compound, comprising diazotizing a substituted or nonsubstituted aromatic polycyclic compound having a diazotizable primary amino group, and successively coupling the resulting diazo component with an azo component having a diazotizable primary amino group, the last azo component being such that --OH group or a group derived from --OH group be present at p-position to an azo group bonded to an aromatic polycyclic ring resulting from the azo component.
A near-infrared ray absorbing polyazo compound having the formula:
Dependencies are inferred from the claim text.