CN-118339237-B - Reversible thermochromic microcapsule pigments

Abstract

The present invention provides a reversible thermochromic microcapsule pigment which is easily changed into a colored state by heating from a decolored state at a temperature in a living environment temperature range or a temperature close to a daily life temperature, and is sensitively restored to the decolored state again. The reversible thermochromic microcapsule pigment is formed by encapsulating a reversible thermochromic composition comprising (A) an electron donating color developing organic compound, (B) a 4-hydroxybenzoate compound represented by the following general formula (1) (wherein R represents a linear or branched alkyl group having 12 to 22 carbon atoms), which is an electron withdrawing compound, (C) a compound such as a chain hydrocarbon as a reaction medium in which electron transfer reactions based on the above (A) and (B) occur reversibly, (D) a linear dibasic acid compound having 3 to 22 carbon atoms, and (E) a compound such as an aromatic hydrocarbon having a melting point of 50 ℃ or more) in a microcapsule.

Inventors

• FUJITA TAKAYUKI

Assignees

• 株式会社百乐
• 百乐墨水株式会社

Dates

Publication Date

20260512

Application Date

20221114

Priority Date

20211130

Claims (4)

1. 1. A reversible thermochromic microcapsule pigment formed by encapsulating in a microcapsule a reversible thermochromic composition which changes to a colored state by heating from a colored state and changes to a colored state by cooling from a colored state, the reversible thermochromic composition comprising: (A) An electron-donating color-developing organic compound, (B) As the electron-withdrawing compound, a 4-hydroxybenzoate compound represented by the following formula (1), (C) As a compound selected from the group consisting of chain hydrocarbons, alicyclic hydrocarbons and halogenated hydrocarbons as a reaction medium in which electron transfer reactions based on (A) and (B) reversibly occur, (D) A linear dibasic acid compound having 3 to 22 carbon atoms, and (E) Para-terphenyl; the composition comprises, by mass, 1 part of the component (A), 0.1 to 50 parts of the component (B), 1 to 200 parts of the component (C), 0.1 to 1.0 parts of the component (D), 0.3 to 2 parts of the component (E), Wherein R represents a linear or branched alkyl group having 12 to 22 carbon atoms.
2. 2. The reversible thermochromic microcapsule pigment according to claim 1, wherein R in the general formula (1) is a linear alkyl group having 14 to 22 carbon atoms.
3. 3. The reversible thermochromic microcapsule pigment according to claim 1 or 2, further comprising (F) an oligomer selected from the group consisting of a styrene-based oligomer having a weight average molecular weight of 200 to 6000, a terpene-based oligomer having a weight average molecular weight of 250 to 4000, and a terpene-phenolic oligomer having a weight average molecular weight of 200 to 2000.
4. 4. The reversible thermochromic microcapsule pigment according to claim 3, wherein the mass ratio of the component (D) to the component (F) is 1.0:3.5 to 1.0:30.0.

Description

Reversible thermochromic microcapsule pigments Technical Field The present invention relates to reversible thermochromic microcapsule pigments. More specifically, the present invention relates to a reversible thermochromic microcapsule pigment which develops color by heating from a decolored state. Background Conventionally, there have been disclosed a reversible thermochromic composition comprising (a) an electron donating organic compound, (B) an electron withdrawing compound, and (C) a reaction medium in which an electron transfer reaction based on the above (a) and (B) occurs reversibly, and a microcapsule pigment having the reversible thermochromic composition encapsulated therein, wherein the composition exhibits a color change behavior that is easily changed to a color-developed state by heating from a color-developed state and is restored to a color-developed state by cooling in a living environment temperature range at a temperature near a temperature of daily life by using a hydroxybenzoate as the component (B) (for example, see patent documents 1 to 4). Although the reversible thermochromic composition exhibits a colored state by heating at a relatively low temperature, it may take a long time to return to the decolored state, and it is difficult to satisfy the practical use. Prior art literature Patent literature Patent document 1 Japanese patent application laid-open No. 2013-159706 Patent document 2 Japanese patent application laid-open No. 2013-231138 Patent document 3 Japanese patent application laid-open No. 2017-14328 Patent document 4 International publication No. 2020/196073 pamphlet Disclosure of Invention Problems to be solved by the invention The present inventors have conducted intensive studies on a reversible thermochromic composition that develops color by heating from a decolored state, and as a result, have found that a reversible thermochromic microcapsule pigment having a reversible thermochromic composition that exhibits a color-developing state easily caused by heating from a decolored state at a temperature close to a daily living temperature in a living environment temperature region and that is sensitively restored to a decolored state again can be obtained by adding specific compounds to the components (a), (B) and (C), and have completed the present invention. Means for solving the problems According to the present invention, the following invention is provided. [1] A reversible thermochromic microcapsule pigment formed by encapsulating in a microcapsule a reversible thermochromic composition which changes to a colored state by heating from a colored state and changes to a colored state by cooling from a colored state, the reversible thermochromic composition comprising: (A) An electron-donating color-developing organic compound, (B) As the electron-withdrawing compound, a 4-hydroxybenzoate compound represented by the following formula (1), (C) As a compound selected from the group consisting of chain hydrocarbons, alicyclic hydrocarbons and halogenated hydrocarbons as a reaction medium in which electron transfer reactions based on (A) and (B) reversibly occur, (D) A linear dibasic acid compound having 3 to 22 carbon atoms, and (E) A compound selected from alcohols, esters, ethers, ketones, amides and aromatic hydrocarbons having a melting point of 50 ℃ or higher; Wherein R represents a linear or branched alkyl group having 12 to 22 carbon atoms. [2] The reversible thermochromic microcapsule pigment according to [1], wherein the alkyl group of the hydroxybenzoate compound represented by the general formula (1) is a linear alkyl group having 14 to 22 carbon atoms. [3] The reversible thermochromic microcapsule pigment according to [1] or [2], wherein the proportion of the component (D) to the component (A) is 0.1 to 1% by mass. [4] The reversible thermochromic microcapsule pigment according to any of [1] to [3], wherein the proportion of the component (E) to the component (A) is 0.3 to 2% by mass. [5] The reversible thermochromic microcapsule pigment according to any one of [1] to [4], further comprising (F) an oligomer selected from the group consisting of a styrene-based oligomer having a weight average molecular weight of 200 to 6000, a terpene-based oligomer having a weight average molecular weight of 250 to 4000, and a terpene-based phenolic oligomer having a weight average molecular weight of 200 to 2000. [6] The reversible thermochromic microcapsule pigment according to [5], wherein the mass ratio of the component (D) to the component (F) is 1.0:3.5 to 1.0:30.0. Effects of the invention The present invention can provide a reversible thermochromic microcapsule pigment which exhibits a reversible color change behavior that is easily changed to a colored state by heating from a decolored state and is again sensitively restored to the decolored state in a living environment temperature range and a temperature close to a temperature in daily life, and which can be appli