Thermochromic Color-Memory Composition Hysteresis Control

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Solution Overview

Problem

Conventional thermochromic materials lack the ability to selectively maintain color states at temperatures below or above the discoloration temperature and interchange these states reversibly, limiting their application in various fields.

Innovation Solution

A thermochromic color-memory composition comprising an electron-donating organic compound, an electron-accepting compound, and an ester compound as a reaction medium, which allows for prominent hysteresis characteristics and reversible discoloration, enabling the composition to maintain either colored or decolored states at normal temperatures by applying heat or cold.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If conventional reversibly thermochromic materials are used, then color change occurs at discoloration temperature, but the ability to selectively maintain color states at normal temperatures is lost

Engineering Contradiction:

Improveability to maintain color statesVSAvoidcolor memory stability

Core Design Contradiction:

Adaptability or versatilityVSReliability

Solution Approach 1:

The patent modifies the physical and chemical parameters of the reaction medium by selecting specific esters with appropriate melting points and molecular structures. This enables the system to maintain distinct color states at normal temperatures while preserving reversible color change capability at discoloration temperature, thus resolving the contradiction between adaptability and reliability.

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The patent creates a composite thermochromic system combining electron-donating compounds, electron-accepting compounds, and specifically selected ester reaction media. This composite approach enables simultaneous achievement of color memory stability and selective color state maintenance, overcoming the limitations of conventional single-material systems.

Inventive Principle:

Principle #40Composite materials

2Reliability

If thermochromic materials with large hysteresis width are designed, then color memory capability is improved, but the freedom in selection of reaction medium is reduced

Engineering Contradiction:

Improvecolor memory capabilityVSAvoidfreedom in reaction medium selection

Core Design Contradiction:

ReliabilityVSAdaptability or versatility

Solution Approach 1:

The patent identifies and utilizes specific parameter ranges of ester compounds (melting point, molecular weight, structural features) that enable large hysteresis width while maintaining versatility in medium selection. This parameter optimization allows achieving color memory capability without unduly restricting the choice of reaction media.

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The patent applies the local quality principle by specifying particular structural characteristics and physical properties for the ester reaction medium that locally optimize hysteresis behavior. This enables the reaction medium to provide enhanced color memory capability while still allowing flexibility in selecting from multiple ester compounds that meet the specified local quality criteria.

Inventive Principle:

Principle #3Local quality

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 thermochromic color-memory composition exhibits a large hysteresis width, allowing reversible discoloration and color retention, enhancing its applicability in fields like recording materials, toys, temperature indication, and printing by effectively reproducing and memorizing colors.

Implementation Method 1

thermochromic color-memory composition which displays reversible discoloration between coloration and decoloration showing prominent hysteresis characteristics according to temperature change

Methodology Applied

Scientific EffectThermochromism: Thermochromism

Data Source

PatentEP3103853B1Thermochromic color-memory composition and thermochromic color-memory microcapsule pigment encapsulating the same

Publication Date: 2018.11.28 THE PILOT INK CO LTD

Figure 1

AI summary

[Problems] An object of the present invention is to provide: thermochromic color-memory composition which effectively expresses a property of being capable of interchangeably memorizing and retaining colors and is thus applicable to various fields; and thermochromic color-memory microcapsule pigment encapsulating the same. [Means for Solution] Provided are thermochromic color-memory composition and thermochromic color-memory microcapsule pigment encapsulating the same, the thermochromic color-memory composition including: (a) a component composed of an electron-donating color-developing organic compound; (b) a component composed of an electron-accepting compound; and (c) a component composed of an ester compound represented by the following Formula (1) as a reaction medium which controls color reaction between the components (a) and (b): (wherein, R represents an alkyl group having 3 to 18 carbon atoms or an aliphatic acyl group having 3 to 18 carbon atoms; X represents a hydrogen atom, an alkyl group having 1 to 3 carbon atoms, an alkoxy group having 1 or 2 carbon atoms or a halogen atom; Y represents a hydrogen atom or a methyl group; and Z represents a hydrogen atom, an alkyl group having 1 to 4 carbon atoms, an alkoxy group having 1 or 2 carbon atoms or a halogen atom).