JP2000343835A - Two-color developing and heat-sensitive recording material - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a two-color developing and heat-sensitive recording material showing outstanding coloring properties and shelf life. SOLUTION: In the heat-sensitive recording material having a two-tier heat- sensitive and color-developing layer which develops a color in varying color tone, formed on a support such as paper, a plastic sheet or a synthetic paper, a first heat-sensitive color developing layer, an intermediate layer, a second heat-sensitive color developing layer which develops a color by smaller energy than the color developing energy of the first heat-sensitive color developing layer and a protecting layer are laminated in that order on a support. At the same time, a chemical compound shown by the formula and a water-soluble zirconium compound are added to the second heat-sensitive color developing layer. In the formula, R1, R2 are an alkyl group with 6 or less carbon atoms.

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 two-color heat-sensitive recording material having an improved red recording portion.

[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-45-140.
No. 39, etc., which are widely used. In general,
The heat-sensitive recording material is prepared by separately dispersing a developer such as a leuco dye and a phenolic substance into fine particles, and then mixing the two, and then adding additives such as a binder, a sensitizer, a filler, and a lubricant. Is applied to a support such as paper, film, synthetic paper, etc., and the color recording is made by a chemical reaction that occurs when one or both of the leuco dye and the developer are melted and contacted by heating. And a sheet-like heat-sensitive recording material is usually prepared. A thermal printer or the like having a built-in thermal head is used for coloring the heat-sensitive recording sheet. This thermal recording method is (1) compared to other recording methods.
There is no noise during recording, (2) there is no need for development and fixing, and (3) maintenance-free. (4) Facsimile field due to features such as relatively inexpensive machines
It is widely used in computer output, printers such as calculators, recorders for medical measurement, automatic ticket vending machines, heat-sensitive recording labels, and the like.

In these fields, attempts have been made to perform multi-color thermal recording using thermal energy differences, and two-color thermal recording systems using leuco dyes have been put into practical use. Two-color thermal recording paper (sheet)
In general, two types of high-temperature and low-temperature color-forming layers, each of which develops a different color tone with a different color-energy on a support, are formed by superimposition, and are roughly classified into the following two types. One of them is a method of obtaining a color tone different from the color tone of the low-temperature coloring layer by mixing colors when the high-temperature coloring layer is colored,
The other is to use a decoloring agent for erasing the low-temperature coloring layer when the high-temperature coloring layer is colored, thereby suppressing the coloring of the low-temperature coloring layer and obtaining the color tone of the high-temperature coloring layer.

[0004]

However, no perfect two-color heat-sensitive recording paper (sheet) has been obtained by any of these methods. For example, the former method has a drawback mainly in two-color separation, and the latter method has a drawback in image storability due to the use of a decoloring agent. At present, as color-developing type thermosensitive recording paper is about to spread to use conditions such as long-term display or recording preservation like ordinary recording materials, the above-mentioned disadvantage is that two-color coloring thermosensitive recording paper (sheet) is widely used. Is an issue that must be solved in order to be fulfilled. In addition, at present, the performance of the red color recording material does not follow the color density, storage stability, and the like as compared with the black color recording material that has been widely used in the past. SUMMARY OF THE INVENTION It is an object of the present invention to provide a two-color heat-sensitive recording material which is excellent in color density and storage stability especially in a red color recording portion in order to enhance recording characteristics in two-color coloring.

[0005]

Means for Solving the Problems The present inventors have intensively studied to improve the above-mentioned disadvantages of the two-color heat-sensitive recording material and completed the present invention. That is, the present invention
(1) In a heat-sensitive recording material provided with two heat-sensitive coloring layers that develop different colors on the support, the color-forming energy of the first heat-sensitive coloring layer, the intermediate layer, and the first heat-sensitive coloring layer on the support. The second heat-sensitive coloring layer, which forms a color with a small energy, and the protective layer are sequentially laminated, and the second heat-sensitive coloring layer is represented by the following formula (1).

[0006]

Embedded image

(In the formula (1), R ₁ and R _{2 each} have 6 carbon atoms.
Represents the following alkyl groups. ) And a two-color heat-sensitive recording material using a water-soluble zirconium compound.

[0008]

BEST MODE FOR CARRYING OUT THE INVENTION As the alkyl group having 6 or less carbon atoms in R ₁ and R ₂ in the formula (1), for example, a methyl group, an ethyl group, an n-propyl group, an isopropyl group, an n-
Butyl group, sec-butyl group, t-butyl group, n-pentyl (amyl) group, isopentyl (isoamyl) group, n
-Hexyl group and the like. Specific examples of the compound represented by the formula (1) include, for example, 3-diethylamino-7-
Phenoxyfluoran, 3-dibutylamino-7-phenoxyfluoran, 3-dipentylamino-7-phenoxyfluoran, 3- (N-methyl-N-propylamino) -7-phenoxyfluoran, 3- (N -Ethyl-
N-isopentylamino) -7-phenoxyfluoran and the like, which are used alone or in combination. The compound represented by the formula (1) is described, for example, in JP-A-9-3
It can be synthesized by a known method as described in JP-A-09272.

As the water-soluble zirconium compound, conventionally known compounds include, for example, zirconium oxychloride, zirconium acetate, zirconium nitrate, ammonium zirconium carbonate, zirconium hydroxychloride, etc., among which weak acids such as zirconium acetate and ammonium zirconium carbonate are exemplified. Zirconium salts are preferred.

The heat-sensitive recording material of the present invention has an energy smaller than that of the support, the first heat-sensitive coloring layer, the intermediate layer for enhancing the effect of separating recording colors (two-color separation), and the first heat-sensitive coloring layer. In the order of the second thermosensitive coloring layer and the protective layer.

In forming the heat-sensitive coloring layer on the heat-sensitive recording material of the present invention, the second layer having a small coloring energy serving as an upper layer is formed.
The thermosensitive coloring layer uses a red coloring compound represented by the formula (1). The first layer that has a large color forming energy as the lower layer
The color-forming compound used in the thermosensitive color-forming layer is selected from the following color-forming compounds, and preferably has an absorption spectrum (for example, in an acetic acid solution) of 550 n.
Those having at least one maximum absorption wavelength between m and 1000 nm are preferred.

In the first and second heat-sensitive coloring layers provided in the heat-sensitive recording material of the present invention, the color-forming compound is 1 to 50% by weight, the color-developing compound shown below is 5 to 80% by weight, and the binder is 1%. ~ 90% by weight, filler and heat fusible compound each 0
To 80% by weight, and other lubricants, surfactants, defoamers and the like are used in any ratio, for example, 0 to 30% by weight. The weight% is the weight ratio of each component in the thermosensitive coloring layer.

In the second heat-sensitive coloring layer, the water-soluble zirconium compound is 0.5 to 50% by weight, preferably 2 to 50% by weight in terms of ZrO2, based on 100% of the total weight of the second heat-sensitive coloring layer when dried. ~ 20% by weight is used.

The first thermosensitive coloring layer serving as the lower layer and the second thermosensitive coloring layer serving as the upper layer are each intended to obtain a recording color independently, and the following points are considered. That is, the heat quantity Q1 necessary for coloring the first heat-sensitive coloring layer and the heat quantity Q2 necessary for coloring the second heat-sensitive coloring layer of the heat-sensitive recording material are smaller in the latter. The component ratio of the thermosensitive coloring layer is considered so as to satisfy the relation that the inequality Q1 is larger than Q2. In order to obtain the calorific relationship necessary for coloring the two thermosensitive coloring layers, a coloring compound having a different melting point, a developing compound having a different melting point, when the melting points of the coloring compounds are similar or the same. When a color-developing compound is used, the presence or absence of a compound that lowers the melting point, such as a heat-fusible compound, can be considered.

The first heat-sensitive color-forming layer on the support has a dry weight of 3 g / m 2 (square meter) or more, preferably 3 to 3 g / m 2 (square meter).
10 g / m @ 2, the second heat-sensitive coloring layer having a dry weight of 0.1 g / m @ 2.
5 to 10 g / m2, preferably 3 to 8 g / m2, are each provided. Further, the first and second thermosensitive coloring layers are separated from each other by providing an intermediate layer in order to improve color separation. Examples of the material used for the intermediate layer include those exemplified as the following binders. Further, if necessary, fillers, heat-fusible compounds, lubricants, various surfactants, etc. Selected and used together. The middle layer has a dry weight of 5
g / m2 or less, preferably in the range of 1 to 3 g / m2. Incidentally, 1 g / m @ 2 is about 1 .mu.m in thickness.

The protective layer is formed using the same material as the above-mentioned intermediate layer, and is 0.1 to 5 g / m 2, preferably 2 to 4 g.
/ M2. Incidentally, the protective layer may be a multilayer as required. In the case of a multilayer, layers similar to those of the intermediate layer may be laminated to form a layer, or one of the layers, preferably the outermost layer, may be a layer of an ultraviolet curable resin.

The second heat-sensitive color-forming layer having a small color-forming energy, which is an upper layer, comprises, in addition to the compound represented by the above formula (1),
It is possible to use a combination of a coloring compound which usually develops a purple-red or yellow color, for example, 3-diethylaminobenzo [a] fluoran, 3- (N-ethyl-N-isopentylamino) benzo [a] fluoran, 3-diethylamino- 7-methylfluorane, 3-diethylamino-7-chlorofluorane, 3-diethylamino-6-methyl-7-chlorofluorane, 3-cyclohexylamino-6-chlorofluorane, 3- (N-ethyl-N- p-tolylamino)-
7-methylfluorane, 2- {2- [4- (dodecyloxy) -3-methoxyphenyl] ethenyl} -quinoline and the like. The amount used for the second thermosensitive coloring is preferably in a range that does not impair the effects of the present invention, for example, a range that does not exceed the amount of the compound represented by the formula (1).

The color-forming compound used in the first heat-sensitive color-forming layer having a large color-forming energy, which is a lower layer, is selected from blue- or black-colored compounds generally used in pressure-sensitive recording paper and thermosensitive recording paper. Examples thereof include fluoran compounds, triarylmethane compounds, spiro compounds, diphenylmethane compounds, thiazine compounds, lactam compounds, fluorene compounds, and the like. Preferably, their absorption spectrum characteristics are 550.
Those having at least one or more maximum absorption wavelength between 1000 nm and 1000 nm are preferred.

Among them, fluoran compounds include, for example, 3-diethylamino-6-methyl-7-anilinofluoran, 3-dibutylamino-6-methyl-7-anilinofluoran, 3- (N-methyl- N-cyclohexylamino) -6-methyl-7-anilinofluoran, 3
-(N-ethyl-N-isopentylamino) -6-methyl-7-anilinofluoran, 3- (N-isobutyl-
N-ethylamino) -6-methyl-7-anilinofluoran, 3- [N-ethyl-N- (3-ethoxypropyl) amino] -6-methyl-7-anilinofluoran,
3- (N-ethyl-N-hexylamino) -6-methyl-7-anilinofluoran, 3-dipentylamino-6
-Methyl-7-anilinofluoran, 3- (N-methyl-N-propylamino) -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-fluoroanilino) fluoran, 3- (p-toluidinoethylamino) -6-methyl-7-anilinofluoran, 3-diethylamino-6-methyl-7- (p
-Toluidino) fluoran, 3-diethylamino-7-
(3,4-dichloroanilino) fluoran, 3-pyrrolidino-6-methyl-7-anilinofluoran, 3-diethylamino-6-chloro-7-ethoxyethylaminofluoran, 3-diethylamino-6-chloro- 7-anilinofluoran, 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-phenylfluoran, 3
-(P-Toluidinoethylamino) -6-methyl-7-
Phenethylfluoran and the like.

As the triarylmethane compound, for example, 3,3-bis (p-dimethylaminophenyl) -6
-Dimethylaminophthalide (alias: crystal violet lactone or CVL), 3,3-bis (p-dimethylaminophenyl) phthalide, 3- (p-dimethylaminophenyl) -3- (1,2-dimethylaminoindole- 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-ethylcarbazole-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.

Examples of the spiro compound include 3-methylspirodinaphthopyran, 3-ethylspirodinaphthopyran, 3,3′-dichlorospirodinaphthopyran,
Benzylspirodinaphthopyran, 3-propylspirobenzopyran, 3-methylnaphtho- (3-methoxybenzo) spiropyran, 1,3,3-trimethyl-6-nitro-8'-methoxyspiro (indoline-2,2'- Benzopyran) and the like, as diphenylmethane compounds, for example, N-halophenyl-leuco auramine,
4-bis-dimethylaminophenylbenzhydrylbenzyl ether, N-2,4,5-trichlorophenylleucouramine and the like; thiazine compounds such as benzoylleucomethylene blue and p-nitrobenzoylleucomethylene blue; Examples of the fluorene-based compound include rhodamine B anilinolactam and rhodamine B-p-chloroanilinolactam, and examples of the fluorene-based compound include 3,6-bis (dimethylamino) fluorenespiro (9,3 ′)-6. '-Dimethylaminophthalide, 3,6-bis (dimethylamino) fluorenespiro (9,3')-6'-pyrrolidinophthalide,
3-dimethylamino-6-diethylaminofluorenespiro (9,3 ')-6'-pyrrolidinophthalide and the like. These coloring compounds are used alone or in combination.

The color-developing compound is not particularly limited as long as it is generally used for pressure-sensitive recording paper or heat-sensitive recording paper. Examples thereof include α-naphthol, β-naphthol, p-octylphenol, 4-t-octylphenol and p-octylphenol. -T-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 2,4′-dihydroxydiphenyl sulfone, bis (3-allyl-4-hydroxyphenyl) sulfone,
-Hydroxy-4'-methoxydiphenyl sulfone, 4
-Hydroxy-4'-ethoxydiphenyl sulfone, 4
-Hydroxy-4'-isopropoxydiphenylsulfone, 4-hydroxy-4'-butoxydiphenylsulfone, methyl bis- (4-hydroxyphenyl) acetate, butyl bis- (4-hydroxyphenyl) acetate, bis-
Phenolic compounds such as benzyl (4-hydroxyphenyl) acetate and 2,4-dihydroxy-2'-methoxybenzanilide; benzyl p-hydroxybenzoate;
Such as ethyl hydroxybenzoate, dibenzyl 4-hydroxyphthalate, dimethyl 4-hydroxyphthalate, ethyl 5-hydroxyisophthalate, 3,5-di-t-butylsalicylic acid, and 3,5-di-α-methylbenzylsalicylic acid; Examples thereof include aromatic carboxylic acid derivatives, aromatic carboxylic acids and metal salts thereof.

A binder and a filler are used in the color-forming layer, the intermediate layer and the protective layer, if necessary. As a filler that can be used,
For example, calcium carbonate, magnesium carbonate, magnesium oxide, silica, white carbon, talc, clay,
Alumina, magnesium hydroxide, aluminum hydroxide,
Aluminum oxide, barium sulfate, polystyrene resin,
Urea-formalin resin and the like.

Examples of usable binders include 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, water-soluble isoprene rubber, alkali salt of styrene / maleic anhydride copolymer, alkali salt of iso (or diiso) butylene / maleic anhydride copolymer, etc. Water-soluble or polyvinyl acetate, vinyl chloride / vinyl acetate copolymer, polystyrene, polyacrylate, polyurethane, styrene / butadiene (SB) copolymer, carboxylated styrene / butadiene (SB) copolymer, styrene / butadiene / acrylic acid copolymer, hydrophobic polymer emulsion such as composite particles of colloidal silica and acrylic resin, and the like. .

Further, a heat-fusible compound is used for the color-forming layer and the protective layer, if necessary. Examples of the heat-fusible compound that can be used 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, aromatic ethers, and aromatic carboxylic acids. Acid derivatives, aromatic sulfonic acid ester derivatives, carbonic acid or oxalic acid diester derivatives, biphenyl derivatives, terphenyl derivatives, etc.
Those which are solid at normal temperature and have a melting point of about 70 ° C. or more can be used.

Examples of waxes include wood wax, carnauba wax, shellac, paraffin, montan wax,
Paraffin oxide, polyethylene wax, polyethylene oxide and the like, as higher fatty acids, for example, stearic acid,
Examples of higher fatty acid amides such as behenic acid include stearic acid amide, oleic acid amide, N-methylstearic acid amide, erucic acid amide, methylolbehenic acid amide, methylolstearic acid amide, methylenebisstearic acid amide, and ethylenebisstearin Acid amides and the like, higher fatty acid anilides such as stearic acid anilide and linoleic acid anilide, acetylated aromatic amines such as acetotoluidide, and naphthalene derivatives such as 1-benzyloxynaphthalene, Benzyloxynaphthalene, 1-hydroxynaphthoic acid phenyl ester and the like include aromatic ethers such as 1,2-diphenoxyethane, 1,4
-Diphenoxyethane, 1,2-bis (3-methylphenoxy) ethane, 1,2-bis (4-methoxyphenoxy) ethane, 1,2-bis (3,4-dimethylphenyl) ethane, 1-phenoxy- 2- (4-chlorophenoxy) ethane, 1-phenoxy-2- (4-methoxyphenoxy) ethane and the like include aromatic carboxylic acid derivatives such as benzyl p-hydroxybenzoate,
Examples of aromatic sulfonic acid ester derivatives include benzyl p-benzyloxybenzoate and dibenzyl terephthalate, for example, phenyl p-toluenesulfonate, phenylmesitylenesulfonate,
-Methylphenyl mesitylenesulfonate and the like are carbonic acid or oxalic acid diester derivatives, for example, diphenyl carbonate, dibenzyl oxalate, dioxalic acid (4
-Methylbenzyl) ester, oxalic acid di (4-chlorobenzyl) ester and the like, as biphenyl derivatives,
For example, p-benzylbiphenyl, p-allyloxybiphenyl and the like are terphenyl derivatives such as m-
Terphenyl and the like are each exemplified.

To the color-forming layer, intermediate layer and protective layer, other lubricants such as zinc stearate, calcium stearate and aluminum stearate, various surfactants, antifoaming agents and the like are added as required.

The heat-sensitive recording material of the present invention is prepared using the above-mentioned materials by the following method, for example. That is, first, a color-forming compound for the first heat-sensitive color-forming layer, a color-forming compound represented by the formula (1) for the second heat-sensitive color-forming layer, a compound represented by the formula (2), The compounds are separately pulverized and dispersed by a dispersing machine such as a ball mill, an attritor, a sand mill or the like together with a binder or other additives as necessary (when pulverization and dispersion are performed by a wet method, usually water is used as a medium) ), Mixing and adding a water-soluble zirconium compound to the first thermosensitive coloring layer coating solution and the second thermosensitive coloring layer coating solution, respectively. Separately, using a binder or other additives as necessary, an intermediate layer coating solution,
A coating solution for the protective layer is prepared. A first thermosensitive coloring layer on a support such as paper, plastic sheet, synthetic paper, etc.
Coating and drying are repeated in the order of forming the intermediate layer, the second thermosensitive coloring layer and the protective layer to obtain the thermosensitive recording material of the present invention. The coating amount of each layer is usually the weight when dried, and the first thermosensitive coloring layer is 3 g / m 2 or more, preferably 3 to 10 g / m 2 (the ratio between the coloring compound and the developing compound is usually the dry weight ratio. 2:
1 to 1:10), the intermediate layer is 5 g / m 2 or less, preferably 1 to 3 g / m 2, and the second thermosensitive coloring layer is 0.5 to 1 g / m 2.
0 g / m 2, preferably 3 to 8 g / m 2, and the protective layer is 0.1 g / m 2.
It is 1 to 5 g / m2, preferably 2 to 4 g / m2.

[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.

Example 1 (Formation of First Thermosensitive Coloring Layer) A mixture having the following composition was pulverized and dispersed using a sand grinder so that the average particle size became 1 μm or less, and each of the liquids [A] and [B] was used. Prepare liquid. [A] solution: 3-diethylamino-7- (o-fluoroanilino) fluoran 25 parts 25% PVA aqueous solution 20 parts water 55 parts [B] solution: bis (3-allyl-4-hydroxyphenyl) sulfone 25 parts 25 % PVA aqueous solution 20 parts Water 55 parts Then, the respective preparations were mixed in the following proportions to prepare a first thermosensitive coloring layer coating liquid, and the weight of the white polyester film having a thickness of 188 μm when dried was 6 g / m 2. The first thermosensitive coloring layer of black color is formed by coating and drying. [A] solution 14 parts [B] solution 28 parts 48% carboxylated styrene butadiene copolymer latex 10 parts

(Formation of Intermediate Layer) On the first thermosensitive coloring layer, 4
A 0% styrene / acrylate copolymer emulsion is applied so as to have a dry weight of 1 g / m 2 (square meter) and dried to form an intermediate layer.

(Formation of Second Thermosensitive Color-forming Layer) A mixture having the following composition is pulverized and dispersed using a sand grinder so that the average particle size becomes 1 μm or less, to prepare a liquid [C]. [C] Solution: Color-forming compound of formula (1) (3- (N-ethyl-N-isopentylamino) -7-phenoxyfluoran 25 parts 25% PVA aqueous solution 20 parts Water 55 parts Next, each prepared solution was A second thermosensitive coloring layer coating solution was prepared by mixing the following proportions, applied to the above-mentioned intermediate layer so that the weight at the time of drying was 5 g / m2, and dried to obtain a second thermosensitive coloring layer having a red coloration. [C] solution 14 parts [B] solution 28 parts 40% styrene / acrylate copolymer emulsion 10 parts Zirconium ammonium carbonate aqueous solution (ZrO2 = 20%) 5 parts

(Formation of Protective Layer) Next, a protective layer coating solution having the following composition is prepared, and is coated and dried on the second thermosensitive coloring layer so that the dry weight becomes 1 g / m 2. 20% colloidal silica dispersion 20 parts 40% styrene / acrylic acid ester copolymer emulsion 10 parts Further ultraviolet curing resin (trade name: Best Cure UV)
HAKURI OP Varnish UP-2, manufactured by TOKA CORPORATION
Using a tester, transfer is performed at about 2 g / m @ 2, and ultraviolet light irradiation is performed to obtain a two-color heat-sensitive recording material of the present invention.

Example 2 A heat-sensitive recording material of the present invention is obtained in the same manner as in Example 1 except that 3-diethylamino-7-phenoxyfluorane is used in place of the compound of the formula (2) in Example 1.

Example 3 A heat-sensitive recording material of the present invention is obtained in the same manner as in Example 1 except that an aqueous solution of zirconium acetate (ZrO 2 = 22%) is used instead of the aqueous solution of ammonium zirconium carbonate in Example 2.

Comparative Example 1 A heat-sensitive recording for comparison was carried out in the same manner as in Example 1 except that 3-diethylamino-7-chlorofluorane was used in place of the compound of the formula (1) in Example 1, except for the solution [D]. Get the material.

Comparative Example 2 A comparative thermosensitive recording material was obtained in the same manner as in Example 1 except that the aqueous solution of zirconium ammonium carbonate in Example 1 was omitted.
Tables 1 and 2 show the quality performance of the present invention and the comparative thermosensitive recording material obtained as described above.

Table 1 Quality Performance Test Results Ground 1) Black Density 2) Red Density 3) Red Moisture Resistance 4) Red Light Resistance 5) Example 1 0.06 2.13 1.85 1.30 1.57 Example 2 0.06 2.11 1.83 1.28 1.60 Example 3 0.06 2.12 1.83 1.29 1.55 Comparative Example 1 0.05 2.05 0.99 0.380 .70 Comparative Example 2 0.06 2.10 1.57 0.46 1.09

1) Background: A value obtained by measuring an uncolored sample with a gray colorimeter of a Macbeth reflection densitometer (model RD-914). 2) Black Density: Gray color of Macbeth reflection densitometer on a color-developed part printed with a printing pulse width of 1.5 milliseconds and an applied voltage of 19 volts using a card printer TH-CPS manufactured by Okura Electric with TDK thermal head LS4105A. The value measured by the measuring part. 3) Red density: a value obtained by measuring a color-developed portion printed under a condition of a print pulse width of 0.8 millisecond with a red measuring unit of a Macbeth reflection densitometer under the above printer conditions. 4) Red humidity resistance: A sample that has developed red color is 55 ° C. and a relative humidity is 9
The value of the background measured by the red measuring unit of the Macbeth reflection densitometer after standing in a 0% humidity chamber for 24 hours. 5) Red lightfastness: A value measured by a Macbeth reflection density type red measuring section after a red-colored sample was left under a fluorescent lamp of 5,000 lux for one week.

As is clear from the table, the two-color heat-sensitive recording material of the present invention has a high red color density and excellent storage stability of the color-formed portion.

[0041]

According to the present invention, a two-color heat-sensitive recording material having remarkably excellent color developability and storage stability was obtained.

Claims (1)

[Claims] 1. A thermosensitive recording material comprising a support and two heat-sensitive coloring layers each of which develops a different color tone on a support, wherein the first heat-sensitive coloring layer, the intermediate layer and the first heat-sensitive coloring layer are formed on the support. The second heat-sensitive coloring layer, which forms a color with an energy smaller than the energy, is sequentially laminated so as to form a protective layer, and the second heat-sensitive coloring layer has the following formula (1). (In the formula (1), R ₁ and R ₂ each represent an alkyl group having 6 or less carbon atoms) and a water-soluble zirconium compound.