JP2994048B2 - Thermochromic material - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a thermochromic material comprising a furfuryl alcohol ester compound of 1 to 4 carboxylic acid and an organic sulfonic acid ester compound which develops a color by heating. The present invention relates to a thermochromic material for providing an irreversible color image which does not lose color even in some cases.

[0002]

2. Description of the Related Art Thermochromic materials are widely used in thermosensitive recording media, but conventionally used thermosensitive recording media are substrates such as paper, synthetic paper, and resin films. A recording device comprising a coloring material comprising a colorless or light-colored coloring material such as a leuco dye and a developer for coloring the coloring material when heated, and a thermosensitive coloring layer in which other additives are dispersed. In this method, the principle is used in which a dye and a developer react to form a color when a heating element such as a thermal head or a hot pen contacts the recording medium.

[0003] Such a conventional thermosensitive recording medium has the advantages that recording can be performed in a short time, low noise generation, low cost, and the like, and various recording recorders, computers, and facsimile machines. Widely used as recording paper for, telex, ticket vending machines, etc., but when exposed to sunlight, or in contact with water or organic liquids such as oils and fats, the coloring image may be erased or the background Has the disadvantage of causing unnecessary color development and cannot withstand long-term storage.
It was only used as a temporary storage medium.

[0004] It is extremely important to improve the stability at the time of such storage. Conventionally, attempts have been made to improve the storage stability by adding various third components. The effect was only temporary because the reaction between the dye and the developer was reversible.

For this reason, thermochromic materials which provide irreversible color images have been studied. For example, a chelate reaction system using iron carboxylate is known, but iron carboxylate is usually used by itself. Due to the coloring, there is a disadvantage that the non-colored portion (background) is colored, and a method of giving an irreversible color image by the reaction of an imino compound and an isocyanate compound has been proposed, but the safety of the compound itself has been proposed. sex,
It is difficult to withstand long-term storage because of its poor water resistance and the like, and its tendency to develop color due to adhesion of oil such as a plasticizer.

Japanese Patent Application Laid-Open No. 49-84638 discloses that a composition containing a component that generates an acid upon exposure and a component that forms an insoluble compound by a thermal reaction under acidic conditions is used to provide excellent storage stability. Although a method of forming an image has been proposed, it is essential to perform a heat treatment following the light irradiation, and the operation is extremely complicated,
It could not be used as a general thermal recording material.

[0007]

Means for Solving the Problems The present inventors have found that an ester compound of furfuryl alcohol easily causes an irreversible color-forming reaction under acidic conditions, and uses this specific furan compound for storage. An attempt was made to form a color image having excellent stability.

In order to use such a specific furan compound as a thermochromic material, it does not show acidity near room temperature, releases an acidic component only when heated, and comes into contact with water or oil, or is exposed to sunlight. It is necessary to use a compound which does not release an acidic component even when exposed to methane, together with the furan compound.

The present inventors have conducted intensive studies to find such a compound. As a result, when an organic sulfonic acid ester compound having a thermal decomposition temperature of 50 ° C. or more was used together with a specific furan compound, a certain amount of the compound was obtained. It develops color only when heated above temperature, and such a mixture is not only extremely stable when stored at room temperature, but also when exposed to oils or moisture or exposed to sunlight. Did not cause unnecessary coloring or fading, and reached the present invention.

That is, the present invention provides the following chemical formula 2 (same as chemical formula 1)
And a thermochromic material comprising an organic sulfonic acid ester compound having a thermal decomposition temperature of 50 ° C. or higher.

[0011]

Embedded image

Hereinafter, the thermochromic material of the present invention will be described in detail.

In the above chemical formula 2, the organic group represented by R includes, for example, formic acid, acetic acid, propionic acid, butyric acid, isobutyric acid, octylic acid, nonanoic acid, lauric acid, stearic acid, acrylic acid, methacrylic acid, oleic acid Acid, benzoic acid, toluic acid, tert-butylbenzoic acid, salicylic acid, tert-butylsalicylic acid, nitrobenzoic acid, cyanobenzoic acid, oxalic acid, malonic acid, butylmalonic acid, succinic acid,
Glutaric acid, adipic acid, azelaic acid, dodecanedicarboxylic acid, tartaric acid, malic acid, maleic acid, fumaric acid,
Itaconic acid, phthalic acid, isophthalic acid, terephthalic acid,
Tricarballylic acid, butane tricarboxylic acid, butene tricarboxylic acid, citric acid, trimellitic acid, butane tetracarboxylic acid, 1-4-valent carboxylic acid or et al.1 to four carboxyl such as pyromellitic acid, biphenyltetracarboxylic acid
Residues excluding the sil group are mentioned.

The thermal decomposition temperature used in the present invention is 50.
Examples of the organic sulfonic acid ester compound having a temperature of not less than ° C include benzenesulfonic acid, p-toluenesulfonic acid,
-Bromobenzenesulfonic acid, 4-methoxybenzenesulfonic acid, 4-benzyloxybenzenesulfonic acid, β-
Monovalent or divalent organic sulfonic acids such as naphthalenesulfonic acid, 1,3-benzenedisulfonic acid, and methanesulfonic acid, and methanol, ethanol, propanol, isopropanol, 2-phenylethanol, 1-phenylpropanol, butanol, and isobutanol , Sec-butanol, tert-butanol, amyl alcohol, cyclohexanol, 2-methylcyclohexanol, 4-methylcyclohexanol, 4-tert-butylcyclohexanol, 2-cyclohexylcyclohexanol, 4-cyclohexylcyclohexanol, 2,6 Aliphatic, alicyclic or heterocyclic monohydric alcohols such as dimethylcyclohexanol, 2,3-dihydroinden-2-ol, 2-phenyl-1,3-dioxan-5-ol or ethylene glycol; Diol, diethylene glycol, propylene glycol, 2,2-dimethyl-1,3-propanediol, 1,4-butanediol, 2,3-butanediol, 2,5-hexanediol, 1,2-cyclohexanediol, And ester compounds with dihydric alcohols such as 1,3-cyclohexanediol, 1,4-cyclohexanediol, and 2,2-bis (4-hydroxycyclohexyl) propane. Particularly preferred are ester compounds of secondary alcohols.

As the organic sulfonic acid ester compound having a thermal decomposition temperature of 50 ° C. or higher used in the present invention, specifically, cyclohexyl-p-toluenesulfonate (melting point 45 ° C., thermal decomposition temperature 132 to 139 ° C.), cyclohexyl- 4-benzyloxybenzenesulfonate (mp 75
° C, thermal decomposition temperature 136 ° C), cyclohexyl-β-naphthalene sulfonate (melting point 70-73 ° C, thermal decomposition temperature 125-126 ° C), 2-methylcyclohexyl-β-
Naphthalene sulfonate (melting point 115 ° C., decomposed simultaneously), 2,6-dimethylcyclohexyl-β-naphthalene sulfonate (melting point 111 ° C., thermal decomposition temperature 127
C), 2-cyclohexylcyclohexylmethanesulfonate (melting point 48 ° C, pyrolysis temperature 78 ° C), 2-cyclohexylcyclohexylbenzenesulfonate (melting point 6
7-69 ° C, decomposed simultaneously), 2-cyclohexylcyclohexyl-β-naphthalenesulfonate (melting point 71-7
2-cyclohexylcyclohexyl-β-naphthalene sulfonate (melting point 120 ° C., thermal decomposition temperature 128 ° C.), 4-tert-butylcyclohexyl-β
-Naphthalene sulfonate (melting point 106 ° C, pyrolysis temperature 132 ° C), 2-phenyl-1,3-dioxane-5-
Ilbenzene sulfonate (melting point 128-129 ° C, thermal decomposition temperature 200 ° C), 1-phenylpropyl-p-toluenesulfonate (melting point 49-51 ° C, thermal decomposition temperature 18)
8 ° C.), 2-phenylethyl-p-toluenesulfonate (melting point 39-41 ° C., thermal decomposition temperature 227-229)
C), 2,3-dihydroinden-2-yl-β-naphthalenesulfonate (melting point 86-88 ° C, thermal decomposition temperature 1)
32-134 ° C.), 1,2-cyclohexylenebis (p
-Toluenesulfonate) (melting point 127-128 ° C, thermal decomposition temperature 200 ° C or more), 1,3-cyclohexylenebis (benzenesulfonate) (melting point 125-127 ° C,
Thermal decomposition temperature: 148 to 150 ° C), 1,4-cyclohexylenebis (methanesulfonate) (melting point: 130 ° C, thermal decomposition temperature: 143 to 144 ° C), 1,4-cyclohexylenebis (benzenesulfonate) (melting point: 146 to 147)
° C, simultaneously decomposed), 1,4-cyclohexylenebis (p
-Toluenesulfonate) (melting point: 158 to 160 ° C, decomposed simultaneously), 2,3-butylenebis (p-toluenesulfonate) (melting point: 78 to 81 ° C, thermal decomposition temperature: 214 to 2)
17 ° C.), 2,5-hexylenebis (p-toluenesulfonate) (melting point 81-83 ° C., thermal decomposition temperature 139)
° C), 2,2-dimethylpropylenebis (p-toluenesulfonate) (melting point 118-120 ° C, thermal decomposition temperature 2
33-237 ° C), 2,2-bis (4-hydroxycyclohexyl) propanebis (methanesulfonate) (melting point 123-124 ° C, decomposed simultaneously), 2,2-bis (4
-Hydroxycyclohexyl) propanebis (benzenesulfonate) (melting point 126 ° C., decomposed simultaneously), 2,2
-Bis (4-hydroxycyclohexyl) propanebis (p-toluenesulfonate) (melting point 149 ° C, decomposed simultaneously) 2,2-bis (4-hydroxycyclohexyl)
Propane bis (p-bromobenzenesulfonate) (melting point 120-122 ° C, decomposed simultaneously), di (cyclohexyl) -1,3-benzenedisulfonate (melting point 85 ° C,
Decomposition at the same time).

The thermochromic material of the present invention comprises a furfuryl ester compound represented by the above formula (2) and a thermal decomposition temperature of
It is composed of an organic sulfonic acid ester compound having a temperature of 0 ° C. or higher, and the compounding ratio thereof is preferably 5 to 500 parts by weight, more preferably 10 to 200 parts by weight, based on 100 parts by weight of the furfuryl ester compound. .

The thermochromic material of the present invention may be used in the form of an aqueous dispersion or a desired material such as toluene, xylene, cyclohexane, methylcyclohexane, cyclohexanone, acetone, methylethylketone, methanol, ethanol, isopropyl alcohol, ethylene glycol or the like. A solution dissolved in an organic solvent, and, if necessary, mixed with other additive components such as a binder and a filler, and a suitable base material, for example, paper, synthetic paper, plastic film, wood, metal plate, glass plate By applying on top of
It can be a thermosensitive recording material or a temperature indicating material that changes color when it reaches a target temperature.

The thermochromic material of the present invention gives a good color image only with the above-mentioned furfuryl ester compound and the above-mentioned organic sulfonic acid ester compound, but a clearer color image can be obtained by adding a phenol compound. May be obtained.

Examples of such phenol compounds include p-phenylphenol, p-tert-octylphenol, p-tert-octylcatechol, bisphenol A, 1,1-bis (p-hydroxyphenyl) butane,
2,2-bis (4-hydroxyphenyl) heptane,
2,2-bis (3-methyl-4-hydroxyphenyl)
Propane, 2,2-bis (3,5-dimethyl-4-hydroxyphenyl) propane, 2,2-bis (3,5-dichloro-4-hydroxyphenyl) propane, bis (4
-Hydroxyphenyl) sulfone, 4-methylphenyl-3,4-dihydroxyphenylsulfone, bis (3-
Allyl-4-hydroxyphenyl) sulfone, 4-hydroxy-4′-isopropoxydiphenyl sulfone, 4
-(4-isopropoxyphenylmercapto) phenol, 4,4′-thiobis (2-tert-butyl-m-resole), 4,4′-thiobis (2-methylphenol),
1,1-bis (4-hydroxyphenyl) cyclohexane, bis (4-hydroxyphenyl) ether, 4-
(3-phenoxy-2-hydroxypropylmercapto) phenol, 1,7-bis (4-hydroxyphenylmercapto) -3,5-dioxaheptane, p-hydroxybenzoic acid, ethyl p-hydroxybenzoate, p-
Butyl hydroxybenzoate, benzyl p-hydroxybenzoate, butyl bis (4-hydroxyphenyl) acetate, 1,1,3-tris (2-methyl-4-hydroxy-5-tert-butylphenyl) butane, 1,3-
Tris (2-methyl-4-hydroxy-5-cyclohexylphenyl) butane, bis [2- (4-hydroxyphenylthio) ethoxy] ethane, dimethyl 4-hydroxyphthalate and the like can be mentioned.

Further, by mixing the thermochromic material of the present invention with a leuco dye, a clearer color image can be obtained. The leuco dye is not particularly limited as long as it is used for general pressure-sensitive recording paper or heat-sensitive recording paper.

Specific examples of these dyes include triarylmethane compounds; for example, 3,3-bis (p-
Dimethylaminophenyl) -6-dimethylaminophthalide (commonly called crystal violet lactone), 3- (p
-Dimethylaminophenyl) -3- (1,2-dimethyl-3-indolyl) phthalide, 3- (p-dimethylaminophenyl) -3- (2-phenyl-3-indolyl)
Phthalide, 3,3-bis (9-ethyl-3-carbazolyl) -5-dimethylaminophthalide, 3,3-bis (2
Diphenylmethane-based compounds such as -phenyl-3-indolyl) -5-dimethylaminophthalide;
Xanthene compounds such as 4-bis (dimethylamino) benzhydrin benzyl ether, N-2,4,5-trichlorophenylleuco auramine; for example, rhodamine-β-anilinolactam, 3-dimethylamino-7-
Methoxyfluorane, 3-dimethylamino-6-methoxyfluorane, 3-dimethylamino-7-chlorofluorane, 3-diethylamino-6-methyl-7-chlorofluorane, 3-diethylamino-6-methyl-7- Xylidinofluoran, 3-diethylamino-6-methyl-
7-anilinofluoran, 3-diethylamino-6-chloro-7- (β-ethoxyethylamino) fluoran,
3-diethylamino-6-chloro-7-anilinofluoran, 3-diethylamino-6-chloro-7-γ-chloropropylaminofluoran, 3-diethylamino-
6,7-dimethylfluoran, 3-diethylamino-7
-Methoxyfluoran, 3-diethylamino-7-N-
Acetyl-N-methylaminofluoran, 3-diethylamino-7-N-methylaminofluoran, 3-diethylamino-7-dibenzylaminofluoran, 3-diethylamino-7-N-methyl-N-benzylaminofluoran , 3-diethylamino-7-N-chloroethyl-
N-methylaminofluoran, 3-diethylamino-7
-N-diethylaminofluoran, 3-diethylamino-7-octylaminofluoran, 3-diethylamino-7- (2-chloroanilino) fluoran, 3-diethylamino-7- (2-carbomethoxyphenylamino)
Fluorane, 3-dibutylamino-6-methyl-7-anilinofluoran, 3-dibutylamino-7- (2-chloroanilino) fluoran, 3-dibutylamino-7-
(2-fluoroanilino) fluoran, 3- (N-methyl-NN-amylamino) -6-methyl-7-anilinofluoran, 3- (N-methyl-N-propylamino)
-6-methyl-7-anilinofluoran, 3- (N-methyl-Nn-hexylamino) -6-methyl-7-anilinofluoran, 3- (N-methyl-N-cyclohexylamino) -6-methyl-7-anilinofluoran,
3- (N-ethyl-p-toluidino) -6-methyl-7
-(P-toluidino) fluoran, 3- (N-ethyl-p
-Toluidino) -7-methylfluoran, 3- (N-ethyl-p-toluidino) -6-methyl-7-anilinofluoran, 3- (N-ethyl-N-isoamylamino)
-6-methyl-7-anilinofluoran, 3- (N-ethyl-Nn-amylamino) -6-methyl-7-anilinofluoran, 3- (N-ethyl-N-n-hexylamino ) -6-Methyl-7-anilinofluoran, 3-
(N-ethyl-N-β-ethylhexylamino) -6
-Methyl-7-anilinofluoran, 3- (N-ethyl-N-isopropylamino) -6-methyl-7-anilinofluoran, 3- (N-ethyl-N-tetrahydrofurfurylamino) -6 -Methyl-7-anilinofluoran, 3-piperidino-6-methyl-7-anilinofluoran, 3-pyrrolidino-6-methyl-7-anilinofluoran, 3-pyrrolidino-6-methyl-7- thiazine compounds such as p-butylphenylaminofluoran; spiro compounds such as benzoyl leucomethylene blue and p-nitrobenzoyl leucomethylene blue;
Examples thereof include 3-methylspirodinaphthopyran, 3-ethylspirodinaphthopyran, 3-benzylspirodinaphthopyran, 3-methylnaphtho (3-methoxybenzo) spiropyran, and the like. It can also be used.

When these leuco dyes are used together with the thermochromic material of the present invention, a good color image can be obtained without using a developer, a sensitizer, etc. which are usually used. Additives used in ordinary thermosensitive recording materials, such as a color developer, a sensitizer, and a storage stabilizer, can also be used.

When the thermochromic material of the present invention is applied to various substrates to form a thermosensitive recording material or a thermosensitive material, it may be atomized in water using an appropriate device to form an aqueous dispersion. Or a solution dissolved in an appropriate organic solvent.

The coating solution may contain, if necessary, polyvinyl alcohol, hydroxyethyl cellulose, methyl cellulose, polyacrylamide polymer, starch, styrene-maleic anhydride copolymer, vinyl acetate-maleic anhydride copolymer, styrene Binders such as butadiene copolymers or modified products thereof, fillers such as silica, kaolin, diatomaceous earth, talc, titanium dioxide, calcium carbonate, magnesium carbonate, aluminum hydroxide, and melamine;
Aliphatic carboxylic acids such as stearic acid and behenic acid or benzoic acid, tert-butylbenzoic acid, phthalic acid, gallic acid, salicylic acid, isopropylsalicylic acid, phenylsalicylic acid, 3,5-di-tert-butylsalicylic acid, 3-methyl-5 -Benzylsalicylic acid, 3,5-di (α-methylbenzyl) salicylic acid, 3-phenyl-5- (α, α-
Dimethylbenzyl) polyvalent metal salts of aromatic carboxylic acids such as salicylic acid such as zinc, magnesium, aluminum, calcium, titanium, manganese, tin, nickel and iron; sensitizers; waxes; light stabilizers; A dispersant, an antifoaming agent and the like can be blended.

[0025]

The present invention will be described in more detail with reference to the following examples. However, the present invention is not limited by the following examples.

Example 1, Comparative Example 1 and Comparative Example 2

2 g of difurfuryl fumarate was dispersed in 10.5 g of a 10% aqueous solution of polyvinyl alcohol, and emulsified and pulverized in a ball mill until the average particle size became 3 μm or less to obtain a dispersion of the furfuryl alcohol derivative (A-1 solution). Obtained.

A dispersion (fluid A-2) using furfuryl-4-phenylphenyl ether in place of difurfuryl fumarate was prepared in the same manner.

2-cyclohexylcyclohexyl-β-
2 g of naphthalene sulfonate was dispersed in 10.5 g of a 10% aqueous solution of polyvinyl alcohol, and emulsified and pulverized in a ball mill until the average particle size became 3 μm or less, to obtain a sulfonic acid ester dispersion (solution B-1).

Further, a dispersion (B-B) using phenyltribromomethylsulfone instead of the above-mentioned sulfonic acid ester is used.
2 liquid) was prepared in the same manner.

Solution A-1 and Solution B-1 (Example 1)
Solution 1 and Solution B-2 (Comparative Example 1) or Solution A-2 and Solution B-
One liquid (Comparative Example 2) was mixed at a weight ratio of 1: 1.
Coating liquids were obtained by sufficiently dispersing the coating liquids, and each of these coating liquids was applied on synthetic paper at a thickness of 32 μm and dried to prepare a thermosensitive recording material.

Using the obtained heat-sensitive recording material, at 60 ° C., 8
Printing was performed for 5 seconds at 0 ° C. and 140 ° C. using a hot pen with a load of 200 g / cm 2, and the color density of the obtained recorded image was measured with a Macbeth densitometer (model RD-933, manufactured by Macbeth).

Table 1 shows the results.

[0034]

[Table 1]

Example 2 and Comparative Examples 3 to 5

Furfuryl-4-cyanobenzoate 5 g
And 3 g of dicyclohexyl-1,3-benzenedisulfonate dissolved in toluene 15, coated and dried on a polyethylene terephthalate film to a thickness of 16 μm, and coated with the thermochromic material of the present invention. (Example 2) was prepared.

For comparison, a thermosensitive recording material using 1,4-difurfuryloxybenzene instead of furfuryl-4-cyanobenzoate (Comparative Example 3) and dicyclohexyl-1,3-benzenedisulfonate were used instead. 4
-Cyanobenzoic acid (Comparative Example 4) or 4-hydroxy-
4'-isopropoxydiphenyl sulfone (Comparative Example 5)
Was used to prepare a thermosensitive recording material.

Using the obtained heat-sensitive recording material, at 60 ° C., 8
Load 200 kg / cm ² using a hot pen at 0 ° C. and 140 ° C.
For 5 seconds, and the color density of the obtained recorded image was measured with a Macbeth densitometer (RD-933, manufactured by Macbeth).

Table 2 shows the results.

[0040]

[Table 2]

Embodiment 3

5 g of difurfuryl terephthalate and 2,
3 g of dibenzenesulfonate of 2-bis (4-hydroxycyclohexyl) propane is dissolved in methylcyclohexanone 15, applied to a polyethylene terephthalate film to a thickness of 32 μm, and dried to apply the thermochromic material of the present invention. A heat-sensitive recording material was prepared.

Using the obtained heat-sensitive recording material, at 60 ° C., 8
Load 200 kg / cm ² using a hot pen at 0 ° C. and 140 ° C.
For 5 seconds, and the color density of the obtained recorded image was measured with a Macbeth densitometer (RD-933, manufactured by Macbeth).

Further, in order to check the storage stability, a temperature of 140 ° C.
After recording for 24 hours under conditions of 40 ° C. and 90% humidity, after storage for 6 hours under dry conditions, and after stamping dioctyl phthalate at 60 ° C. under dry conditions for 3 hours under dry conditions The color density of each of the background portion and the printing portion was measured.

Table 3 shows the results.

[0046]

[Table 3]

Embodiment 4

2 g of difurfuryl terephthalate and 2,
2 g of dibenzenesulfonate of 2-bis (4-hydroxycyclohexyl) propane is dispersed in 21 g of a 10% aqueous solution of polyvinyl alcohol, and emulsified and pulverized in a ball mill so that the average particle size becomes 3 μm or less. A liquid was prepared, coated on a polyethylene terephthalate film so as to have a thickness of 32 μm, and dried to prepare a thermosensitive recording material coated with the thermochromic material of the present invention.

Using the obtained heat-sensitive recording material, printing was performed at 140 ° C. using a hot pen at a load of 200 kg / cm ² for 5 seconds, and the color density of the obtained recorded image was measured using a Macbeth densitometer (RD-933 manufactured by Macbeth Co., Ltd.). (Type).

Further, in order to check the storage stability, a temperature of 140 ° C.
After recording for 24 hours under conditions of 40 ° C. and 90% humidity, after storage for 6 hours under dry conditions, and after stamping dioctyl phthalate at 60 ° C. under dry conditions for 3 hours under dry conditions The color density of the background portion and the printed portion was measured.

Table 4 shows the results.

[0052]

[Table 4]

Example 5, Comparative Examples 6 and 7

Difurfuryl terephthalate 2 g, 2,2
2 g of dibenzenesulfonate of bis (4-hydroxycyclohexyl) propane and 3-dibutylamino-6
-Methyl-7-anilinofluorane (0.5 g) was dispersed in a 10% aqueous solution of polyvinyl alcohol (21 g) to give an average particle size of 3;
μ or less in a ball mill to prepare a thermochromic material dispersion of the present invention, applied and dried on a polyethylene terephthalate film to a thickness of 32 μm, A thermosensitive recording material coated with the material (Example 5) was prepared.

Further, a heat-sensitive recording material using bisphenol A instead of 2,2-bis (4-hydroxycyclohexyl) propane-dibenzenesulfonate (Comparative Example 6)
And a heat-sensitive recording material using p-hydroxybenzoic acid (Comparative Example 7) was similarly prepared.

Using the obtained heat-sensitive recording material, printing was performed for 5 seconds under a load of 200 kg / cm ² at 140 ° C. using a hot pen, and the color density of the obtained recorded image was measured using a Macbeth densitometer (RD-933 manufactured by Macbeth Co., Ltd.). (Type).

Further, in order to check the storage stability, a temperature of 140 ° C.
After recording for 24 hours under conditions of 40 ° C. and 90% humidity, after storage for 6 hours under dry conditions, and after stamping dioctyl phthalate at 60 ° C. under dry conditions for 3 hours under dry conditions The color density of the background portion and the printed portion was measured.

Table 5 shows the results.

[0059]

[Table 5]

Embodiment 6

A thermochromic material of the present invention was prepared by mixing difurfuryl fumarate and 1,2-propanediol bis (p-toluenesulfonate) at a weight ratio of 2/1.
This thermochromic material is sandwiched between two slides,
At 210 ° C., 210 ° C. and 220 ° C. for 5 seconds each, and measure its color density by Macbeth densitometer (Model RD-933 manufactured by Macbeth).
Was measured by

Table 6 shows the results.

[Table 6]

Embodiment 7

Difurfuryl fumarate and 2-phenyl-1,3-dioxan-5-ylbenzenesulfonate are mixed at a weight ratio of 2/1 to prepare a thermochromic material of the present invention. Sandwiched between two slides, 1
Heat at 50 ° C., 160 ° C., and 170 ° C. for 5 seconds each, and measure the color development density with a Macbeth densitometer (RD-933 manufactured by Macbeth).
(Type).

Table 7 shows the results.

[Table 7]

Embodiment 8

4 g of difurfuryl terephthalate and 2,
2-bis (4-hydroxycyclohexyl) propane-
2 g of dimethanesulfonate is added to methylcyclohexane 15
The thermosensitive recording material was coated on a polyethylene terephthalate film to a thickness of 32 μm and dried to prepare a thermosensitive recording material coated with the thermochromic material of the present invention.

Using the obtained heat-sensitive recording material, printing was performed at 150 ° C. using a hot pen at a load of 200 g / for 5 seconds, and the color density was measured using a Macbeth densitometer (RD-933 manufactured by Macbeth Co.).
(Type).

The color-developed heat-sensitive recording material was immersed in acetone for 30 seconds to wash out the non-color-developed portions.
After 168 hours exposure to fluorescent light of 15000 lux, 6
After immersion in hot water of 0 ° C. for 3 hours and in octyl phthalate of 60 ° C. for 3 hours, the density of each colored portion was measured.

Table 8 shows the results.

[0071]

[Table 8]

From the results of each of the above Examples, the thermochromic material of the present invention gives a high-density irreversible color-developed image upon heating, and the color-developed image is exposed to ultraviolet rays, or reacts with water or oil. It is clear that the storage stability is extremely excellent without the contact being erased or the non-colored portion not being unnecessarily colored.

Further, since the thermochromic material of the present invention can arbitrarily determine the coloring temperature by appropriately selecting the material, it is useful not only as a thermosensitive recording material but also as a temperature indicating material. it is obvious.

[0074]

According to the thermochromic material of the present invention, a color image having excellent storage stability can be formed.

Embedded image

────────────────────────────────────────────────── ─── Continuation of front page (56) References JP-A-49-25938 (JP, A) JP-A-3-189189 (JP, A) (58) Fields investigated (Int. Cl. ⁶ , DB name) B41M 5/28-5/34 C09K 9/02 CA (STN) REGISTRY (STN)

Claims (1)

(57) [Claims] 1. A thermochromic material comprising at least one furfuryl ester compound represented by the following chemical formula 1 and an organic sulfonic acid ester compound having a thermal decomposition temperature of 50 ° C. or higher. Embedded image