Azo Dye Compound with Aminopyrazole Coupler for Thermal Transfer

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Solution Overview

Problem

Current coloring agents for image-recording materials, such as thermal transfer dyes, color toners, and color filters, face challenges in achieving optimal color reproduction, lightfastness, heat resistance, and solubility, with existing azo dyes not fully satisfying the requirements for high-quality color reproduction and stability under various conditions.

Innovation Solution

A novel azo dye compound with a specific structure, characterized by an aminopyrazole coupler and a carbonyl-substituted imidazole diazo component, offering improved lightfastness and solubility, is developed for use in ink sheets, color toners, and color filters, enhancing their optical characteristics and transfer sensitivity.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Illumination intensity

If conventional azo dyes are used to achieve favorable spectral characteristics for color reproduction, then color reproduction quality is improved, but lightfastness and heat resistance are insufficient

Engineering Contradiction:

Improvecolor reproduction qualityVSAvoidlightfastness and heat resistance

Core Design Contradiction:

Illumination intensityVSReliability

Solution Approach 1:

The patent modifies the molecular structure of azo dyes by introducing specific substituents (electron-withdrawing groups like -NO2, -CN, -SO3R at positions 5 and 6 of the coupler ring, and electron-donating groups at positions 3 and 4) to optimize the balance between spectral characteristics and stability. This structural parameter change enhances both color reproduction quality and lightfastness simultaneously

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The invention creates composite dye molecules combining a diazo component (with specific structural features like sultone groups or carbonyl groups) with a coupler component (aminopyrazole or similar structures). This composite molecular architecture integrates the advantages of both components to achieve superior color properties and stability

Inventive Principle:

Principle #40Composite materials

2Adaptability or versatility

If thermal transfer dye is used to enable gradation recording by changing energy applied to thermal head, then recording flexibility and image quality are improved, but the number of available dyes with all necessary properties is extremely limited

Engineering Contradiction:

Improverecording flexibilityVSAvoidavailability of suitable dyes

Core Design Contradiction:

Adaptability or versatilityVSEase of manufacture

Solution Approach 1:

The patent divides the dye molecule into distinct functional segments: a diazo component (providing thermal transferability and spectral properties) and a coupler component (providing stability and solubility). This segmentation allows independent optimization of each segment's properties and facilitates systematic synthesis of new dye variants

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The invented dye structure serves multiple functions simultaneously: it provides favorable spectral characteristics for color reproduction, excellent lightfastness, good solubility in various solvents, and high thermal transferability. This multi-functionality expands the range of applicable dyes for thermal transfer recording

Inventive Principle:

Principle #6Universality (Multi-functionality)

3Illumination intensity

If coloring agents are used to achieve high transparency for OHP applications, then transparency is improved, but lightfastness deteriorates

Engineering Contradiction:

ImprovetransparencyVSAvoidlightfastness

Core Design Contradiction:

Illumination intensityVSReliability

Solution Approach 1:

The patent optimizes molecular parameters by introducing specific substituent patterns that maintain high transparency while enhancing lightfastness. The electron-withdrawing groups at positions 5 and 6 of the coupler ring and the specific diazo component structure achieve this balance by modifying the HOMO-LUMO energy gap and stabilizing the dye against photodegradation

Inventive Principle:

Principle #35Parameter changes

Applied Scientific Principles

This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.

Function Achieved in This Case

The novel azo dye compound provides excellent optical characteristics, lightfastness, and solubility, enabling high-quality color reproduction and improved image storability and transfer sensitivity in thermal transfer recording, while reducing the environmental and working loads in ink sheet formation.

Implementation Method 1

having an excellent optical characteristic with sharp absorption

Methodology Applied

Scientific EffectLight absorption: Absorption (EM radiation)

Implementation Method 2

heating a thermal transfer material that has a hot-melt ink layer formed on a support (base film), with a thermal head to thereby melt the ink

Methodology Applied

Scientific EffectThermal heating: Heating

Implementation Method 3

heating a thermal transfer material that has a thermal transfer dye-containing dye donor layer on a support, with a thermal head to thereby thermally diffuse and transfer the dye

Methodology Applied

Scientific EffectThermal diffusion: Diffusion

Data Source

PatentUS8158317B2Azo dye compound, coloring composition, ink sheet for thermal transfer recording, thermal transfer recording method, color toner, ink for inkjet, and color filter

Publication Date: 2012.04.17 FUJIFILM CORP

AI summary

An azo dye of the following formula:wherein R1, R2, R3, R4 and R6 each independently represent a hydrogen atom or a substituent; and R5 represent a substituent. The dye has an excellent optical characteristic with sharp absorption and excellent fastness.