Thermochromic Dye Composition Using pH-Sensitive Molecules

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Solution Overview

Problem

Current thermochromic compositions are limited by the availability of leuco dyes, which restrict color transitions, require multiple dye mixing, and often use health-concerning developers like Bisphenol A, necessitating the need for cost-effective, versatile, and tunable color-changing systems.

Innovation Solution

A thermochromic composition comprising a pH-sensitive dye molecule, a matrix with a defined melting point, and an optional developer, where the dye and matrix are combined above the melting point to create a two-component system that changes color at specific temperatures, eliminating the need for separate developers and allowing for multiple color transitions.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If leuco dye-based thermochromic compositions are used, then color change functionality is achieved, but color transition options are limited and multiple dyes must be mixed

Engineering Contradiction:
Improvecolor transition optionsVSAvoidnumber of dyes to mix
Core Design Contradiction:
Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The patent changes the chemical parameter of the dye molecule itself, transitioning from leuco dye to pH-sensitive dye. This fundamental parameter change enables multiple color transitions (yellow, red, purple, blue, green) from a single dye type, eliminating the need to mix multiple dyes while expanding color transition options.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent extracts and eliminates the developer component (such as Bisphenol A) from the thermochromic system. By removing this necessary but problematic component, the invention achieves developer-free operation, simplifying the system and eliminating health concerns associated with traditional developers.

Inventive Principle:
Principle #2Taking out (Extraction)

2Reliability

If traditional developers like Bisphenol A are used, then color development is achieved, but health concerns arise requiring replacement

Engineering Contradiction:
Improvecolor developmentVSAvoidhealth concerns
Core Design Contradiction:
ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The patent completely removes the developer substance from the thermochromic composition. The pH-sensitive dye directly undergoes color change in response to temperature-induced pH changes in the matrix, eliminating the need for any developer substance and thereby eliminating all health concerns associated with traditional developers like Bisphenol A.

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The pH-sensitive dye serves its own color development function without requiring an external developer. The dye molecule itself responds to pH changes caused by matrix melting, enabling self-developing thermochromic behavior that is both reliable and safe.

Inventive Principle:
Principle #25Self-service

3Adaptability or versatility

If leuco dye systems are used, then thermochromic effect is achieved, but cost limitations and limited color options persist

Engineering Contradiction:
Improvecolor optionsVSAvoidcost effectiveness
Core Design Contradiction:
Adaptability or versatilityVSEase of manufacture

Solution Approach 1:

The patent changes the fundamental parameter of the chromogenic mechanism from leuco dye chemistry to pH-sensitive dye chemistry. This enables a single dye to provide multiple color transitions at different pH levels, dramatically expanding color options while simplifying manufacturing by eliminating the need to source and mix multiple specialized leuco dyes.

Inventive Principle:
Principle #35Parameter changes

4Adaptability or versatility

If multiple dyes are mixed to achieve desired color transitions, then color versatility is improved, but manufacturing complexity increases

Engineering Contradiction:
Improvecolor transitionsVSAvoiddye mixing process
Core Design Contradiction:
Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The patent fundamentally changes the dye parameter from leuco type to pH-sensitive type, which inherently provides multiple color states (yellow, red, purple, blue, green) within a single dye molecule. This eliminates the need for complex multi-dye mixing processes while maintaining or enhancing color transition versatility.

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

This approach provides a simple method to produce a variety of thermochromic dyes with multiple color options and transitions, reducing costs and health risks, while enabling customization for various applications by adjusting the matrix's melting point and developer interaction.

Implementation Method 1

a matrix, wherein the matrix comprises a material having a defined melting point

Methodology Applied
Scientific EffectMelting: Melting

Implementation Method 2

the thermochromic composition exhibits a first color at a first temperature and a second color at a second temperature

Methodology Applied
Scientific EffectThermochromism: Thermochromism

Data Source

PatentUS11524515B2Thermochromic dye compositions and method for preparing same
Publication Date: 2022.12.13 XEROX CORP

AI summary

A thermochromic composition including a dye molecule; a matrix, wherein the matrix comprises a material having a defined melting point; and an optional developer. A process for preparing a thermochromic composition, including providing a dye; heating a matrix above its melting point; adding the heated matrix to the dye until the dye dissolves in the matrix; optionally, adding a developer; wherein the thermochromic composition exhibits a first color at a first temperature and a second color at a second temperature; wherein the first color and the second color are different; and wherein the first temperature and the second temperature are different.