Azo dye, dye composition, colorant, colored molded article, method for producing colored anodic oxide film, and method for producing dye

Azo dyes formulated without heavy metals or halogens, using diazo coupling reactions, address the need for environmentally friendly and durable colored anodic oxide films on aluminum, offering a variety of hues from green to brown to purple.

WO2026141195A1PCT designated stage Publication Date: 2026-07-02HODOGAYA CHEMICAL CO LTD
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Patent Information

Authority / Receiving Office
WO · WO
Patent Type
Applications
Current Assignee / Owner
HODOGAYA CHEMICAL CO LTD
Filing Date
2025-12-19
Publication Date
2026-07-02

AI Technical Summary

Technical Problem

There is a need for azo dyes that do not contain heavy metals or halogens and exhibit excellent lightfastness and heat resistance, capable of forming a variety of colors such as purple, blue, green, yellow, red, brown, and black, to meet environmental and aesthetic demands for anodized aluminum coatings.

Method used

Development of azo dyes represented by general formulas (1) and (2), which are free from heavy metals and halogens, and can form colored anodic oxide films with specific lightfastness and heat resistance properties, achieved through a diazo coupling reaction between diazotized compounds and coupler components.

Benefits of technology

The azo dyes provide colored anodic oxide films with excellent light resistance and heat resistance, forming a range of colors from green to brown to purple, with minimal environmental impact, and are suitable for use in anodized films of aluminum and aluminum alloys.

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Abstract

The present invention relates to an azo dye represented by general formula (1) or (2) below.　[In formulas (1) and (2), R1-R4 each independently represent –H or –NO2 and any one or two of R1-R4 represent –NO2; R5-R18 each independently represent –H, –NH2, –OH, –SO3X, –COOX, –NO2, –SO2CH3, –SO2CH2CH3, a C1-3 alkyl group, or a C1-12 amide group optionally having a substituent; in formula (1), any one to three of R5-R11 are –NH2 and any one to three of R5-R11 are –SO3X; in formula (2), any one to three of R12-R18 are –NH2 and any one to three of R12-R18 are –SO3X; and each X independently represents a nonchromogenic cation.]
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