JP2002274048A - Thermal recording material - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a thermal recording material which has a color tone of a moderate black for images, and is excellent in preservation property such as coloring sensitivity, heat-resistance, moisture-resistance and light-resistance. SOLUTION: This thermal recording material contains a specified black coloring compound, a specified red coloring compound, CVL or a benzoyl leuco methylene blue, and 2,4'-dihydroxy diphenyl sulfone as a color developing compound on a plastic film or a synthetic paper.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a heat-sensitive recording material, and more particularly to a photographic-like heat-sensitive recording material having a moderate black color tone and excellent color development sensitivity, heat resistance, moisture resistance, and light resistance. .

[0002]

2. Description of the Related Art A heat-sensitive recording material utilizing a colorless or pale-colored color-forming substance and a color-developing substance capable of coloring the color-forming substance when heated is disclosed in JP-B-43-4160 and JP-B-45-1403.
No. 9 etc. and widely used. Generally, a thermosensitive recording material is prepared by separately dispersing a developer such as a leuco dye and a phenolic substance into fine particles separately, then mixing the two, and adding a binder, a sensitizer, a filler, a lubricant, etc. Adds an agent to form a coating solution, and is applied to a support such as paper, film, or synthetic paper. Heating allows the leuco dye and / or the developer to melt and come into contact with the color reaction to form a color reaction record. In general, a sheet-like heat-sensitive recording material is prepared. For color development of such a heat-sensitive recording sheet, a thermal printer or the like having a built-in thermal head is used. Compared with other recording methods, this heat-sensitive recording method is (1) no noise is generated at the time of recording, (2) there is no need for developing and fixing, (3) maintenance-free, and (4)
It is widely used in the facsimile field, computer output, printers such as calculators, recorders for medical measurement, automatic ticket vending machines, heat-sensitive recording labels, etc. .

In recent years, as a means for providing photographic gradation and high-quality images, printout of input images by a video camera or scanner by a video printer or the like having a built-in thermal printer has been increasing. To obtain rich gradation and high quality image quality depends on the technology of hardware, but the color tone and various storability are based on the heat-sensitive recording material itself. Conventionally, heat-sensitive recording materials using bisphenol A, which is a mainstream color developing compound, have a photographic-like image close to black with a moderate color tone, but have the disadvantage of image deterioration during long-term storage. . or,
Bisphenol A has been the subject of recent debate about environmental hormone suspicions, and the thermal recording products industry has been abolished. Bisphenol S and its derivatives are used as a color developing compound having good storability. However, since the color tone is black with a bias toward blue to green, there is no problem in displaying characters, bar codes, etc. Is unsuitable for the image. Various methods have been proposed to improve the color tone without impairing the storability, specifically heat resistance, moisture resistance and light resistance, but none of them have been found to be satisfactory.

[0004]

SUMMARY OF THE INVENTION It is an object of the present invention to overcome the disadvantages of the prior art as described above. That is,
An object of the present invention is to provide a photographic-like heat-sensitive recording material having a moderate black color tone without impairing the storage stability such as heat resistance, moisture resistance and light resistance, and having excellent color sensitivity.

[0005]

The present inventor has made various studies to achieve the above object, and as a result, completed the present invention. That is, the present invention provides (1) a heat-sensitive color-forming layer comprising, as a main component, a colorless or light-colored color-forming compound and a color-developing compound capable of coloring the color-forming compound when heated on a plastic film or synthetic paper. In the recording material, the thermosensitive coloring layer is represented by the following formula (1) as a black-based coloring compound.

[0006]

Embedded image

A compound represented by the following formula (2):

[0008]

Embedded image Is a CV as a blue-based coloring compound.
L or benzoylleucomethylene blue, 2,4′-dihydroxydiphenylsulfone as a color-developing compound, (2) a heat-sensitive recording material characterized by the following formula (100) based on 100 parts of the compound represented by the formula (1). 2. The heat-sensitive recording material according to claim 1, wherein the compound represented by 2), CVL or benzoylleucomethylene blue is contained in a range of 0.5 to 20 parts by weight.

[0009]

DETAILED DESCRIPTION OF THE INVENTION In the present invention, a compound represented by the formula (1) (CA) is formed on a plastic film or synthetic paper.
S #: 59129-79-2), a compound represented by the formula (2), CVL
(Crystal violet lactone), benzoyl leucomethylene blue, and 2,4'-dihydroxydiphenyl sulfone as main components, respectively, and a binder as shown below and other necessary fillers and sensitizers (heat-fusible) Compound), and other additives. For the compound represented by the formula (2), see JP-A-9-309272.

In the present invention, a thermosensitive coloring layer containing a substance capable of coloring when heated on a smooth surface of a plastic film or synthetic paper is coated with a coating liquid composed of the above-mentioned materials in a dry weight of usually 1 to 20 g / m ² , It is preferably applied so as to have a concentration of 5 to 15 g / m ² and dried to form a thermosensitive coloring layer. Further, an intermediate layer may be provided between the plastic film or synthetic paper and the thermosensitive coloring layer, or a protective layer or the like may be provided on the thermosensitive coloring layer. The material for forming the intermediate layer and the protective layer can be appropriately selected from a binder and, if necessary, a filler, a sensitizer (a heat-fusible compound), and other lubricants. .
It is provided in the range of 1 to ²⁰ g / m ² .

The component ratio of the thermosensitive coloring layer of the present invention is represented by the following formula (1).
Is usually 1 to 50% by weight, preferably 5 to 50% by weight.
The compound represented by the formula (2), CVL (crystal violet lactone) or benzoyl leucomethylene blue is usually 0.05 to 5% by weight, preferably 0.2 to 2% by weight, respectively. '-Dihydroxydiphenyl sulfone is usually 1 to 60% by weight, preferably 10 to 40% by weight, a binder is 1 to 60% by weight, and a filler and a sensitizer (a heat-fusible compound) are each 0 to 70% by weight. %,
Other lubricants, surfactants and the like are each used in an arbitrary ratio, for example, usually 0 to 20% by weight, respectively (% by weight is the weight ratio of each component in the thermosensitive coloring layer). In order to form a heat-sensitive color developing layer having a medium black color tone and excellent image storability, a more preferable embodiment is that, among the above-mentioned compositions, the respective amounts of use are expressed by the formula (1) in weight ratio. A compound represented by the formula (2), CVL
(Cryster violet lactone) or benzoyl leucomethylene blue is usually 0.5 to 20 parts, preferably 2 to 10 parts each, and 2,4'-dihydroxydiphenyl sulfone is usually 1 to 60 parts, preferably 10 to 40 parts.
Used in the range of parts by weight. When the amount of the compound represented by the formula (2), CVL (crystal violet lactone) or benzoyl leucomethylene blue exceeds the above-mentioned amount ratio, there is no problem with the color tone, but the storage stability such as heat resistance, moisture resistance and light resistance is lowered. Cause. In the heat-sensitive recording material of the present invention, a color-forming compound or a color-developing compound other than the main components other than the present invention may be used in combination.

The plastic film or synthetic paper used as a support in the present invention is, for example, a thermoplastic polymer film such as polyethylene, polypropylene or polystyrene, the same film containing an inorganic pigment, or the same film containing a void (hollow). Etc. are used. These films or synthetic papers have a surface wetting tension of 35 dyn / cm or more because of the need to provide a thermosensitive coloring layer as a support.
It is preferably at least 40 dyn / cm, more preferably 50 dyn / cm.
Dyn / cm or more is preferred. Therefore, for a film having a low wetting tension, a film having the above wetting tension can be obtained by applying a corona discharge treatment or applying a surfactant or the above-mentioned intermediate layer, and the coating property between the film and the thermosensitive coloring layer can be obtained. And the adhesiveness can be increased.

The color-forming compound that can be used in combination in the present invention is not particularly limited as long as it is generally used for pressure-sensitive recording paper or heat-sensitive recording paper. Specific examples include, for example, fluoran compounds, triarylmethane compounds,
Examples include spiro compounds, diphenylmethane compounds, thiazine compounds, lactam compounds, and fluorene compounds.

Specific examples of the fluoran compounds include, for example, 3-diethylamino-6-methyl-7-anilinofluoran, 3-dibutylamino-6-methyl-7-anilinofluoran, 3-dipentylamino- 6-methyl-7-anilinofluoran, 3- (N-methyl-N-propylamino) -6-methyl-7-anilinofluoran, 3- (N-methyl-N-cyclohexylamino)-
6-methyl-7-anilinofluoran, 3- (isobutyl-N-ethylamino) -6-methyl-7-anilinofluoran, 3- (N-ethyl-N-isopentylamino) -6-methyl -7-anilinofluoran, 3- (N
-Ethyl-N-hexylamino) -6-methyl-7-anilinofluoran, 3- [N-ethyl-N- (3-ethoxypropyl) amino] -6-methyl-7-anilinofluoran, 3 -(N-ethyl-N-tetrahydrofurylamino) -6-methyl-7-anilinofluoran, 3-
Diethylamino-6-methyl-7- (p-chloroanilino) fluoran, 3-diethylamino-6-methyl-7
-(P-toluidino) fluoran, 3-diethylamino-7- (o-chloroanilino) fluoran, 3-dibutylamino-7- (o-chloroanilino) fluoran, 3
-Diethylamino-7- (o-fluoroanilino) fluoran, 3-dibutylamino-7- (o-fluoroanilino) fluoran, 3-diethylamino-7- (3,4
-Dichloroanilino) fluorane, 3-pyrrolidino-6
-Methyl-7-anilinofluoran, 3-diethylamino-6-chloro-7-ethoxyethylaminofluoran, 3-diethylamino-6-chloro-7-anilinofluoran, 3-diethylamino-6-chloro-7 -Methylfluoran, 3- (p-toluidinoethylamino)-
7-methylfluoran, 3-diethylamino-7-methylfluoran, 3-diethylamino-7-chlorofluorane, 3-diethylamino-7-octylaminofluoran, 3-diethylamino-7-phenylfluoran,
3- (p-toluidinoethylamino) -6-methyl-7
-Phenethylfluoran and the like.

Specific examples of the triarylmethane compound include, for example, 3,3-bis (p-dimethylaminophenyl) phthalide and 3- (p-dimethylaminophenyl)-
3- (1,2-dimethylaminoindol-3-yl)
Phthalide, 3- (p-dimethylaminophenyl) -3-
(2-methylindol-3-yl) phthalide, 3-
(P-dimethylaminophenyl) -3- (2-phenylindol-3-yl) phthalide, 3,3-bis (1,
2-dimethylindol-3-yl) -5-dimethylaminophthalide, 3,3-bis (1,2-dimethylindol-3-yl) -6-dimethylaminophthalide, 3,
3-bis) 9-ethylcarbazol-3-yl) -5
Dimethylaminophthalide, 3,3- (2-phenylindol-3-yl) -5-dimethylaminophthalide, 3
-P-dimethylaminophenyl-3- (1-methylpyrrol-2-yl) -6-dimethylaminophthalide and the like.

Further, specific examples of the spiro compound include, for example, 3-methylspirodinaphthopyran, 3-ethylspirodinaphthopyran, 3,3'-dichlorospirodinaphthopyran, 3-benzylcypyrodinaphthopyran, -Propylspirobenzopyran, 3-methylnaphtho- (3-methoxybenzo) spiropyran, 1,3,3-trimethyl-6-nitro-8'-methoxyspiro (indoline-
2,2′-benzopyran) and the like are specific examples of diphenylmethane-based compounds, for example, N-halophenyl-leuco auramine, 4,4-bis-dimethylaminophenylbenzhydryl benzyl ether, N-2,4,5 -Specific examples of thiazine compounds include, for example, p-nitrobenzoylleucomethylene blue and the like, and specific examples of lactam compounds include, for example, rhodamine B anilinolactam and rhodamine B-p-chloride. Anilinolactam and the like are specific examples of the fluorene-based compound, for example, 3,6-bis (dimethylamino) fluorenespiro (9,3 ′)-6-′dimethylaminophthalide, 3,6-bis (dimethylamino) Fluorenespiro (9,3 ')-6'-pyrrolidinophthalide, 3-dimethyla Roh-6-diethylamino-fluorene-spiro (9,3 ') - 6'-like pyrrolidinopyridine phthalide can be mentioned. These color-forming compounds are used alone or in combination of two or more.

In the present invention, the color-developing compound which can be used in combination with the color-developing compound represented by the formula (3) is not particularly limited as long as it is generally used in pressure-sensitive recording paper or heat-sensitive recording paper. Examples include phenol compounds, aromatic carboxylic acid derivatives having a phenolic hydroxyl group, aromatic carboxylic acids and metal salts thereof.

Specific examples of the phenolic compound include, for example, α-naphthol, β-naphthol, p-octylphenol, 4-t-octylphenol, pt-butylphenol, p-phenylphenol, 1,1-bis (p- (Hydroxyphenyl) propane, 2,2-bis (p-hydroxyphenyl) propane (alias: bisphenol A or BPA), 2,2-bis (p-hydroxyphenyl) butane, 1,1-bis (p-hydroxyphenyl) Cyclohexane, 4,4'-thiobisphenol, 4,4'-cyclohexylidenediphenol, 2,
2 '-(2,5-dibromo-4-hydroxyphenyl)
Propane, 4,4-isopropylidenebis (2-t-butylphenol), 2,2′-methylenebis- (4-chlorophenol), 4,4′-dihydroxydiphenylsulfone, bis (3-allyl-4-hydroxyphenyl) ) Sulfone, 4-hydroxy-4′-methoxydiphenylsulfone, 4-hydroxy-4′-ethoxydiphenylsulfone, 4-hydroxy-4′-isopropoxydiphenylsulfone, 4-hydroxy-4′-butoxydiphenylsulfone and the like. Can be

Specific examples of the aromatic carboxylic acid derivative or aromatic carboxylic acid include methyl bis (4-hydroxyphenyl) acetate, butyl bis (4-hydroxyphenyl) acetate, benzyl bis (4-hydroxyphenyl) acetate, Phenolic compounds such as 2,4-dihydroxy-2′-methoxybenzanilide, benzyl p-hydroxybenzoate, ethyl p-hydroxybenzoate,
Dibenzyl hydroxyphthalate, dimethyl 4-hydroxyphthalate, ethyl 5-hydroxyisophthalate, 3,
Examples thereof include aromatic carboxylic acid derivatives such as 5-di-t-butylsalicylic acid and 3,5-di-α-methylbenzylsalicylic acid, aromatic carboxylic acids and metal salts thereof.

Specific examples of the binder which can be used include, for example, methylcellulose, methoxycellulose, hydroxyethylcellulose, carboxymethylcellulose, sodium carboxymethylcellulose, cellulose, polyvinyl alcohol (PVA), carboxyl group-modified polyvinyl alcohol, sulfonic acid group-modified polyvinyl alcohol, Polyvinylpyrrolidone, polyacrylamide, polyacrylic acid, starch and derivatives thereof, casein, gelatin, aqueous isoprene rubber, styrene / maleic anhydride copolymer alkali salt, iso (or diiso) butylene / maleic anhydride copolymer salt, etc. Water-soluble or styrene / butadiene (SB) copolymer, carboxylated styrene / butadiene (SB) copolymer, styrene / butadiene / acrylic Acid-based copolymer, polyvinyl acetate, polyvinyl chloride, vinyl chloride / vinyl acetate copolymer, polystyrene, acrylic resin, acrylic / styrene resin, polyacrylate, polyester, polycarbonate, polyurethane, polybutyral, epoxy resin, Furan resin, vinyl toluene resin, rosin ester resin,
Examples include hydrophobic polymer compounds such as composite particles of colloidal silica and an acrylic copolymer, and emulsions thereof.

Other additives used as needed include, for example, fillers and heat-fusible compounds (sensitizers). Specific examples of the filler include calcium carbonate, magnesium carbonate, magnesium oxide, silica, white carbon, talc, clay, alumina, magnesium hydroxide, aluminum hydroxide, aluminum oxide, barium sulfate, polystyrene resin, acrylic resin, polyolefin resin, Benzoguanamine resin, melamine resin, urea-formalin resin and the like can be mentioned.

Specific examples of the heat-fusible compound include waxes such as animal and vegetable waxes and synthetic waxes, higher fatty acids, higher fatty acid amides, higher fatty acid anilides, acetylated aromatic amines, naphthalene derivatives, and aromatic ethers. , Aromatic carboxylic acid derivatives, aromatic sulfonic acid ester derivatives, carbonic acid or oxalic acid diester derivatives,
Biphenyl derivatives, terphenyls, and the like that are solid at room temperature and have a melting point of about 70 ° C. or more can be used.

Specific examples of waxes include wood wax, carnauba wax, shellac, paraffin, montan wax, acid or paraffin, polyethylene wax, polyethylene oxide, and the like, and higher fatty acids include, for example, stearic acid and behenic acid. Examples of the higher fatty acid amide include stearic acid amide, oleic acid amide, N-methylstearic acid amide, erucic acid amide, methylolbehenic acid amide, methylolstearic acid amide, methylenebisstearic acid amide, and ethylenebisstearic acid amide. The higher fatty acid anilide includes, for example, stearic acid anilide and linoleic acid anilide, and the acetylated aromatic amine includes, for example, acetotoluide.

Further, specific examples of the naphthalene derivative include:
For example, 1-benzyloxynaphthalene, 2-benzyloxynaphthalene, 1-hydroxynaphthoic acid phenyl ester and the like are specific examples of aromatic ethers, for example, 1,2-diphenoxyethane, 1,4-diphenoxyethane, , 2-bis (3-methylphenoxy) ethane,
1,2-bis (4-methoxyphenoxy) ethane, 1,
2-bis (3,4-dimethylphenyl) ethane, 1-phenoxy-2- (4-chlorophenoxy) ethane, 1-
Specific examples of aromatic carboxylic acid derivatives include phenoxy-2- (4-methoxyphenoxy) ethane and the like, for example, benzyl p-hydroxybenzoate, benzyl p-benzyloxybenzoate, dibenzyl terephthalate and the like. However, specific examples of the aromatic sulfonic acid ester derivative include, for example, p-toluenesulfonic acid phenyl ester, phenyl mesitylene sulfonate,
Specific examples of carbonic acid or oxalic acid diester derivatives include, for example, diphenyl carbonate, dibenzyl oxalate, di (4-methylbenzyl) oxalate, and di (4-methyl oxalate).
Chlorobenzyl) ester and the like, specific examples of the biphenyl derivative include, for example, p-benzylbiphenyl and p-allyloxybiphenyl, and specific examples of the terphenyl derivative include, for example, m-terphenyl.

In addition, lubricants such as zinc stearate, calcium stearate, and aluminum stearate, various surfactants, defoamers, ultraviolet absorbers, and the like are added as required.

Using the above materials, a thermosensitive recording material of the present invention is prepared by the following method, for example. That is, first, a compound represented by the formula (1), a compound represented by the formula (2), CVL or benzoylleucomethylene blue, and 2,4′-dihydroxydiphenylsulfone are separately bound to each other by a conventional method, if necessary. Pulverized and dispersed with a dispersing machine such as a ball mill, attritor, and sand mill together with the additives described above, and then mixed to prepare a coating solution for the thermosensitive coloring layer, and to smooth a plastic film or synthetic paper (the coated surface is subjected to corona treatment in advance). The heat-sensitive recording material of the present invention is obtained by applying the composition on a surface with a bar coater, a blade coater, or the like so that the weight when dried is usually 1 to 20 g / m ² .

If necessary, an intermediate layer may be provided between the thermosensitive coloring layer and the support, or an overcoat layer may be provided on the thermosensitive coloring layer. The intermediate layer and the overcoat layer are pulverized and dispersed in the same manner as in the preparation of the thermosensitive coloring layer coating solution together with a binder or other additives as necessary, to obtain an intermediate layer coating solution or a protective layer coating solution, and then dried. It is applied so that the weight at the time is usually 0.1 to 20 g / m ² .

A compound represented by the formula (1), a compound represented by the formula (2) on a plastic film or synthetic paper,
The thermosensitive recording material of the present invention provided with a thermosensitive coloring layer containing a CVL or benzoylleucomethyl blue coloring compound and 2,4′-dihydroxydiphenylsulfone has a moderate black color tone for images. It has excellent storage stability such as color development sensitivity, heat resistance, moisture resistance, and light resistance.

[0029]

EXAMPLES The present invention will be described in more detail with reference to examples, but the present invention is not limited to these examples. In the examples, "parts" indicates parts by weight and "%" indicates% by weight.

Example 1 (Formation of thermosensitive coloring layer) A mixture having the following composition was pulverized and dispersed using a sand grinder so as to have an average particle size of 1 μm or less. C]
A liquid [D] was prepared. [A] Solution: Compound represented by formula (1) 25 parts 25% PVA aqueous solution 20 parts Water 55 parts [B] Solution: CVL 25 parts 25% PVA aqueous solution 20 parts Water 55 parts [C] Solution: Formula (2) 25 parts 25% PVA aqueous solution 20 parts water 55 parts [D] Liquid: 2,4'-dihydroxydiphenyl sulfone 25 parts 25% PVA aqueous solution 20 parts water 55 parts Next, each prepared solution is mixed at the following ratio. To prepare a coating solution for the heat-sensitive coloring layer, apply it on a synthetic paper YUPO FPG-80 (trade name, manufactured by Oji Yuka Synthetic Paper Co., Ltd.) so that the dry weight becomes 7 g / m ² , and then dry it. A coloring layer was obtained. [A] liquid 24 parts [B] liquid 1 part [C] liquid 1 part [D] liquid 48 parts 20% stearic acid amide dispersion 15 parts 40% styrene / acrylate copolymer emulsion 15 parts

(Formation of Protective Layer) Further, a protective layer coating solution having the following ratio was applied onto the thermosensitive coloring layer so that the dry weight was 3 g / m ² and dried to form a protective layer. The heat-sensitive recording material of the present invention is obtained. 40% styrene / acrylate copolymer emulsion 20 parts 5% bentonite dispersion 40 parts 30% zinc stearate dispersion 3 parts

Example 2 A thermosensitive recording material of the present invention is obtained in the same manner as in Example 1 except that benzoylleucomethylene blue is used in place of CVL in Example 1.

Example 3 The heat-sensitive recording material of the present invention is obtained in the same manner as in Example 1, except that the solution [B] and the solution [C] of Example 1 are each used in an increased amount of 2 parts.

Comparative Example 1 A mixture having the following composition was pulverized and dispersed using a sand grinder so that the average particle diameter became 1 μm or less, to prepare liquids [H]. [H] solution: bisphenol A 25 parts 25% PVA aqueous solution 20 parts water 55 parts Then, instead of the thermosensitive coloring layer coating solution of Example 1, a thermosensitive coloring layer coating solution having the following ratio was used. Similarly, a heat-sensitive recording material for comparison is obtained. [A] solution 24 parts [H] solution 48 parts 20% stearic acid amide dispersion 15 parts 40% styrene / acrylic ester copolymer emulsion 15 parts

Comparative Example 2 A comparative thermosensitive recording material was obtained by using bisphenol S (4,4'-dihydroxydiphenyl sulfone) instead of bisphenol A of Comparative Example 1. Tables 1 and 2 show the quality performance of the heat-sensitive recording material of the present invention and the heat-sensitive recording material for comparison obtained as described above.

Table 1 Quality Performance Table Background 1) Color density 2) Color tone 3) Heat resistance 4) Moisture resistance 5) Light resistance 6) Example 1 0.02 1.61 4-5 1.60 1.38 4- 5 Example 2 0.02 1.60 4-5 1.60 1.40 4-5 Example 3 0.03 1.65 4-5 1.64 1.40 4-5 Comparative Example 1 0.03 1 .55 Standard 1.60 0.98 4 Comparative Example 2 0.03 1.50 1-2 1.50 1.40 3

1) Background The undeveloped portion of the prepared sample was measured with a Macbeth reflection densitometer RD-9.
A value measured with a type 14 (Macbeth reflection density). 2) Color density Density of the prepared sample was measured using a commercially available video printer (Sony Corporation).
VIDEO GRAPHIC PRINTER), a solid black image was printed, and the image density was measured with a Macbeth reflection densitometer RD-914 (reflection density). 3) Color Tone The color tone of the sample at a Macbeth reflection density of about 0.9 was determined using a gray scale (JIS L 0804) with the image color tone of Comparative Example 1 (using bisphenol A) as a standard. Judgment: no color difference: from "5" to 0.
Color tone difference every 5 steps: Performed in the range of "1". 4) Heat resistance Macbeth reflection density of the image portion of the sample after being left in a thermostat at 60 ° C. for 24 hours. 5) Moisture resistance The Macbeth reflection density of the image portion of the sample after being left in a humidity chamber at 60 ° C. and a relative humidity of 90% for 24 hours. 6) Light fastness The unprinted portion of the sample was taken under a fluorescent lamp of 5,000 lux under 100
Discoloration before and after time irradiation is represented by gray scale (JIS L 0
804). The judgment value is the same as in the color tone judgment, without discoloration: discoloration from "5" in 0.5 steps:
Performed within the range of “1”.

As is clear from Table 1, the color image of the heat-sensitive recording material of the present invention by a video printer shows the same color tone as that of the heat-sensitive recording material using bisphenol A, and the background, color density and heat resistance, moisture resistance, light resistance, etc. Excellent storage stability.

[0039]

According to the present invention, a heat-sensitive recording material having a medium black color tone for images and having excellent storage stability such as color sensitivity, heat resistance, moisture resistance, and light resistance was obtained.

Claims (2)

[Claims] 1. A thermosensitive recording material comprising a plastic film or synthetic paper provided with a thermosensitive coloring layer mainly composed of a colorless or pale-colored coloring compound and a coloring compound capable of coloring the coloring compound when heated. The thermosensitive coloring layer is represented by the following formula (1) as a black coloring compound. Is represented by the following formula (2): Is a CV as a blue-based coloring compound.
A heat-sensitive recording material comprising L or benzoylleucomethylene blue and 2,4'-dihydroxydiphenylsulfone as a color-developing compound. 2. A compound represented by the formula (2), CVL or benzoylleucomethylene blue in a weight ratio of 0.5 to 20 parts with respect to 100 parts of the compound represented by the formula (1). Item 1. The heat-sensitive recording material according to Item 1.