JPH11165463A - Heat-sensitive recording material - Google Patents

Abstract

PROBLEM TO BE SOLVED: To perform a judgment for genuineness by a simple method wherein on a supporting body wherein an optical unevenness is partially formed, especially a chain line-containing supporting body, a heat-sensitive recording layer mainly containing a reactant and a co-reactant which reacts with the reactant when being heated, and forms a coloring body. SOLUTION: A supporting body on which an optical unevenness is partially formed, is such a supporting body wherein a clear unevenness is provided so that specified characters, patterns or the like for a judgment of genuineness can be easily visually recognized by the passing light when light is made to pass through the supporting body. Also, a reactant and a co-reactant which are used for this heat-sensitive recording material may be compounds which form a coloring body by a reaction with each other, and area combinations or the like of an inorganic compound, an organic compound and a polyhydric hydroxy aromatic compound. The heat-sensitive recording material is obtained by providing a heat-sensitive recording layer mainly containing the reactant and the co-reactant, on the supporting body. Since the judgment for genuineness is possible by simply observing with passing light, it is excellent in forgery- preventive property.

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 heat-sensitive recording material excellent in forgery prevention.

[0002]

2. Description of the Related Art A thermosensitive recording material generally comprises a support having thereon a thermosensitive recording layer mainly comprising a colorless or pale-colored electron-donating dye precursor and an electron-accepting developer.
By heating with a thermal head, a hot pen, a laser beam or the like, an electron-donating dye precursor and an electron-accepting color developer react instantaneously to obtain an image. JP-B-43-4160, JP-B-43-160 No. 45-14039.

In general, such a heat-sensitive recording material has advantages that an image can be obtained with a relatively simple apparatus, maintenance is easy, and no noise is generated. It is widely used in a wide range of fields such as computer terminals, label printing machines, vending machines such as ticketing machines, and the like. In particular, when the thermal recording material is applied to uses such as tickets, voting tickets, securities, receipt documents, etc., it is desired that the authenticity of the issued ticket can be easily confirmed.

Some proposals have been made so far to provide a thermosensitive recording material with a technology for preventing forgery. For example, Japanese Patent Application Laid-Open No. 62-278084 discloses a method in which a colored concealing layer is provided on a thermosensitive coloring layer in order to make it impossible to discriminate between a colored portion and a non-colored portion of the thermosensitive coloring layer. JP-A-63-
Japanese Patent No. 126783 discloses a method in which a toner is fixed on a heat-sensitive coloring layer, and the heat-sensitive coloring layer immediately below the toner is colored. JP Hei 3
JP-A-19-34991 discloses a method in which a heat-sensitive recording layer which is opaque at room temperature but becomes transparent by heating is provided on a magnetic recording layer. JP-A-4-129794 and JP-A-4-182188
Nos. 7,186,554, 7,266,763, and the like use a difference in absorptivity in a near-infrared wavelength region between a recording portion and a non-recording portion. JP-A-5-278372, 5-
249873, 8-216515, 4-1
No. 26877, No. 6-29860 and the like, a reversible thermosensitive coloring layer and a printing layer using the same ink as the coloring hue of the coloring layer are provided, or a reversible thermosensitive coloring layer and a hologram layer are combined. A method using a reversible thermosensitive coloring layer, such as a combination of a reversible thermosensitive coloring layer and a general thermosensitive coloring layer. JP-A-6-166264 proposes various methods such as a method in which a fluorescent dye is contained in a heat-sensitive recording layer and a pattern is printed on the surface thereof with an ultraviolet absorbent. However, all of these are complicated in the manufacturing process because the heat-sensitive recording material has a multilayer structure, require special materials, and require a special light source for authenticity determination after recording. There was also a problem in actual use.

[0005]

SUMMARY OF THE INVENTION An object of the present invention is to provide a thermosensitive recording material which can be authenticated by a simple method and which is excellent in preventing forgery.

[0006]

Means for Solving the Problems The inventors of the present invention provided a reactant and a reaction with the reactant when heated on a support having a partially formed optical density, particularly a transparent support. By providing a heat-sensitive recording layer mainly containing a co-reactant forming a body, an intended heat-sensitive recording material can be obtained. Further, by setting the haze value of the heat-sensitive recording layer to 80% or less, a clearer watermark pattern can be seen.

[0007]

BEST MODE FOR CARRYING OUT THE INVENTION The heat-sensitive recording material of the present invention is formed on a support having a partially formed optical density, in particular, a transparent support, by reacting the reactant and reacting with the reactant when heated. And a heat-sensitive recording layer mainly containing a co-reactant forming the body.

The support having a partially formed optical density used in the heat-sensitive recording material of the present invention is a specific material for judging authenticity by transmitting light when light is transmitted through the support. What is necessary is just to provide a sharp shade portion so that characters, figures, etc. can be easily visually recognized. That is, examples of the support include paper, various nonwoven fabrics, woven fabrics, synthetic resin films such as polyethylene terephthalate and polypropylene, and synthetic paper. In particular, as long as the optical density portion is not lost, paper laminated with a synthetic resin such as polyethylene or polypropylene, or a composite sheet obtained by combining various supports can be arbitrarily used according to the purpose. However, in consideration of economic efficiency and ease of disposal and reuse, among these, a paper-based support is most preferable.

As a method of providing specific characters, figures, and the like for authenticity judgment which can be easily visually recognized by transmitted light on a paper support, a method of producing a paper containing a liquid containing a dye or a pigment in the state of a wet paper at the time of papermaking. There is also a method of spraying from the nozzle to form a dark color part reaching the inside of the paper layer, a method of printing on the surface of the paper support, etc., but the degree of freedom of design of characters and figures and the difficulty of forgery are considered. In this case, the clearing method is most preferable.
Further, in the case of a support such as a synthetic resin film or synthetic paper, a method of partially reducing the thickness of the support by applying pressure or the like to a part such as a character or a figure during manufacturing, a method of forming fine holes, There is also a method of infiltrating with ink or the like.

[0010] The production of transparent paper is made of fine wires made of metal or synthetic resin, oil paper, characters made of thin films made of metal or synthetic resin,
In the case of a circular net paper machine, a net for papermaking with a figure attached to the surface, or a net for papermaking in which the mesh is filled with characters and figures in a synthetic resin, etc. In the case of a paper machine, it is carried out by attaching it as an upper net of a dandy roll and making the paper. In any case, in the characters and figures, that is, in the transparent portion, in addition to the low filler and fine fibers having high light scattering ability, the pulp fibers are also reduced. Is identified as a light pattern that is optically faint compared to the uncleared part.

As the pulp constituting the paper support partially formed with optical shading used in the present invention, any pulp usually used for papermaking can be used. That is, bleached chemical pulp such as softwood kraft pulp, hardwood kraft pulp, softwood sulphite pulp, and hardwood sulphite pulp can be used. Further, mechanical pulp having high whiteness may be used. Furthermore, grass fibers such as straw, espato, bagasse, kenaf, hemp,
Pulp manufactured from bast fibers such as mulberry, ganpi, mitsumata, cotton, etc. may be used. Pulp may be used alone, or two or more kinds may be used in combination. However, at the time of clarification processing, the characters and patterns of clarification are sharpened, that is, in order to sharply change the thickness of the paper layer of the part where clarification is performed and the part where clarification is not performed, the fiber is thin. And a shorter one is advantageous.

The pulp is beaten by a beater such as a double disc refiner in order to improve various properties of the paper such as suitability for papermaking, strength, smoothness, uniformity of formation, and clarity of transparency.

The beaten pulp slurry is made by a hand-making method using a paper cage, or by a paper machine such as a fourdrinier paper machine or a round net paper machine. Dispersing aid for pulp slurry used for drying, drying,
Various additives such as a wet paper strength enhancer, a filler, a sizing agent, and a fixing agent can all be added as needed. Further, if necessary, a pH adjuster, a dye, a colored pigment, a fluorescent whitening agent and the like can be added.

The dispersing aids include, for example, polyethylene oxide, polyacrylamide, smelt, and the like. The paper strength enhancers include, for example, anionic paper strength enhancers such as vegetable gum, starch, carboxy-modified polyvinyl alcohol, cationized starch, and the like. Cationic polyacrylamide, a cationic paper strength enhancer such as polyamide polyamine epichlorohydrin resin, as a filler, for example, clay, kaolin,
Examples of the sizing agent include calcium carbonate, barium sulfate, titanium oxide, aluminum hydroxide, and magnesium hydroxide. Examples of the sizing agent include higher fatty acid salts, rosin, rosin derivatives such as maleated rosin, dialkylketene dimer, alkenyl or alkyl succinate, and epoxy. Fatty acid amide,
Polysaccharide esters and the like, as a fixing agent, for example, aluminum sulfate, polyvalent metal salts such as aluminum chloride, cationized starch, cationic polymers such as polyamide polyamine epichlorohydrin resin, etc., as a pH regulator hydrochloric acid,
Caustic soda, sodium carbonate and the like are used.

The paper support partially formed with optical shading used in the present invention is a liquid containing various additives including a water-soluble polymer additive, and has a tab size and a size. Processing with a press or the like is also possible.

The water-soluble polymer additives used in the present invention include, for example, starch, cationized starch, polyvinyl alcohol, carboxy-modified polyvinyl alcohol, carboxymethyl cellulose, hydroxymethyl cellulose,
Hydroxyethyl cellulose, cellulose sulfate, gelatin, casein, sodium polyacrylate,
Styrene-maleic anhydride copolymer sodium salt, sodium polystyrene sulfonate and the like are used. Further, petroleum resin emulsion, styrene-
Dispersion of ammonium salt of maleic anhydride copolymer alkyl ester, alkyl ketene dimer emulsion, styrene / butadiene copolymer, ethylene / vinyl acetate copolymer, polyethylene, polyvinylidene chloride and the like can be mentioned. As other additives, as an antistatic agent, sodium chloride, calcium chloride, and potassium nitrate as inorganic electrolytes, glycerin and polyethylene glycol as hygroscopic substances, clay as a pigment, kaolin,
Talc, barium sulfate, titanium oxide and the like are used as a pH adjuster, such as hydrochloric acid, caustic soda, and sodium carbonate, and other additives such as a dye and a fluorescent whitening agent can be used in combination.

The thickness of the support is not particularly limited as long as the optical density formed on the support can be visually confirmed. The thickness is selected in the range of 20 μm to 300 μm depending on the use.

The heat-sensitive recording layer provided on the support is required to be able to reproduce the optical shading partially formed on the support when the heat-sensitive recording material of the present invention is viewed with transmitted light. . For this reason, the thickness of the thermosensitive recording layer provided on the support is preferably in the range of 0.5 μm to 10 μm, and particularly preferably in the range of 1 μm to 6 μm. In this range, optical density can be clearly confirmed.

It is more preferable that the heat-sensitive recording layer itself is optically transparent or translucent, and the haze value of the heat-sensitive recording layer is preferably 80% or less. It is particularly preferably at most 30%. In order to improve the transmittance of the thermal recording layer,
There are a method of making the refractive indexes of various materials contained in the heat-sensitive recording layer equal or close to each other, and a method of reducing light scattering by air, particles and the like in the heat-sensitive recording layer.

The haze value (cloudiness value) of the heat-sensitive recording layer according to the present invention can be measured using an integrating sphere type light transmittance measuring device according to JIS K7105. The haze value of the heat-sensitive recording layer is obtained by applying a coating solution for the heat-sensitive recording layer on a transparent film and drying it. In order to reduce the scattered light on the surface, a sample for measuring the haze value of the heat-sensitive recording layer with the transparent adhesive tape adhered to the smeared surface is used as the haze value of the heat-sensitive recording layer.

The heat-sensitive recording layer according to the present invention mainly contains a reactant and a co-reactant. If the haze value is 80% or less, various additives such as pigments and various organic compounds are added as other materials. Is also good.

The reactant and co-reactant used in the heat-sensitive recording material of the present invention may be compounds which form a colored body by mutual reaction, and conventionally, inorganic and organometallic compounds and polyvalent hydroxyaromatic compounds A combination of an electron-donating dye precursor and an electron-accepting developer, a combination of a diazo compound and a coupler such as a hydroxy aromatic compound, a combination of an imino compound and an isocyanate compound, and an electron-donating dye precursor. Combinations of isocyanate compounds are known, and these combinations can be used alone or in combination depending on the application.

The inorganic material used in the heat-sensitive recording material of the present invention,
Examples of the organic metal compound include copper nitrate, ferric chloride, iron stearate, copper stearate, silver behenate, iron oleate, and iron benzoate. These can be used alone or in combination of two or more.

The polyhydric hydroxy aromatic compound used in the heat-sensitive recording material of the present invention includes tannic acid, catechol, stearyl gallate, propyl gallate, pyrogallol and the like. These can be used alone or in combination of two or more.

The generally colorless or light-colored electron-donating dye precursor used in the heat-sensitive recording material of the present invention is typified by those generally used in pressure-sensitive recording paper and heat-sensitive recording paper, but is particularly limited. Not something. Specific examples include the following, for example.

Examples of the triarylmethane compound and the indolylphthalide compound include 3,3-bis (p-dimethylaminophenyl) -6-dimethylaminophthalide (crystal violet lactone) and 3,3-bis (p -Dimethylaminophenyl) phthalide, 3- (p-
Dimethylaminophenyl) -3- (1,2-dimethylindol-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-bis (2-phenylindol-3-yl)-
5-dimethylaminophthalide, 3-p-dimethylaminophenyl-3- (1-methylpyrrol-2-yl) -6
-Dimethylaminophthalide and the like,

As the diphenylmethane-based compound, 4,
4'-bis (dimethylaminophenyl) benzhydryl benzyl ether, N-chlorophenylleuco auramine, N-2,4,5-trichlorophenyl leuco auramine, etc.

As the anilinofluoran compound, 3
-Diethylamino-6-methyl-7-anilinofluoran, 3-piperidino-6-methyl-7-anilinofluoran, 3-pyrrolidino-6-methyl-7-anilinofluoran, 3-diethylamino-6- Methyl-7- (4-
Methylanilino) fluoran, 3-diethylamino-6
-Methyl-7- (4-n-butylanilino) fluoran, 3-diethylamino-6-methyl-7- (4-ethoxyanilino) fluoran, 3-pyrrolidino-6-methyl-7- (4-methylanilino) fluoran, 3-pyrrolidino-6-methyl-7- (4-n-butylanilino)
Fluoran, 3-pyrrolidino-6-methyl-7- (4-
Ethoxyanilino) fluoran, 3-di-n-propylamino-6-methyl-7-anilinofluoran, 3-di-n-butylamino-6-methyl-7-anilinofluoran, 3-di- n-pentylamino-6-methyl-7-
Anilinofluoran, 3- (N-methyl-NNn-propyl) amino-6-methyl-7-anilinofluoran,
3- (N-ethyl-NN-propyl) amino-6-methyl-7-anilinofluoran, 3- (N-ethyl-N
-Isoamyl) amino-6-methyl-7-anilinofluoran, 3- (N-ethyl-N-isobutyl) amino-
6-methyl-7-anilinofluoran, 3- (N-methyl-N-cyclohexyl) amino-6-methyl-7-anilinofluoran, 3- (N-methyl-N-tetrahydrofuran-2-ylmethyl) Amino-6-methyl-7-
Anilinofluoran, 3- (N-ethyl-N-tetrahydrofurylmethyl) amino-6-methyl-7-anilinofluoran, 3- (N-methyl-N-tetrahydrofuran-2-yl) amino-6 Methyl-7-anilinofluoran, 3- (N-ethyl-N-tetrahydrofuryl)
Amino-6-methyl-7-anilinofluoran, 3-dimethylamino-6-methyl-7-anilinofluoran,
3- (N-methyl-N-ethyl) amino-6-methyl-
7-anilinofluoran, 3-isopentylamino-6
-Methyl-7-anilinofluoran, 3-di-n-butylamino-6-methyl-7- (2-fluoroanilino)
Fluoran, 3-di-n-butylamino-6-methoxy-7-anilinofluoran, 3-di-n-butylamino-6-methyl-7- (2,6-dimethylanilino) fluoran, 3- (N-ethyl-N-3-ethoxypropyl) amino-6-methyl-7-anilinofluoran, 3
-(N-methyl-N-3-ethoxypropyl) amino-
6-methyl-7-anilinofluoran, 3-diethylamino-6-methyl-7- (3-trifluoromethylanilino) fluoran, 3-diethylamino-7- (3-trifluoromethylanilino) fluoran, 3 -Diethylamino-7- (2-chloroanilino) fluoran, 3-
Diethylamino-7- (3-chloroanilino) fluoran, 3-di-n-butylamino-7- (3-chloroanilino) fluoran, 3-diethylamino-7- (2-fluoroanilino) fluoran, 3-diethylamino-7
-(2-methoxyanilino) fluoran, 3-pyrrolidino-7- (2-chloroanilino) fluoran, 3-pyrrolidino-7- (3-chloroanilino) fluoran, 3-
Pyrrolidino-7- (2-methoxyanilino) fluoran, 3-diethylamino-7- (2-isopentyloxycarbonylanilino) fluoran, 3- (N-ethyl-Np-tolyl) amino-6-methyl- 7-anilinofluoran and the like,

Other fluoran compounds and xanthene compounds include 3-pyrrolidino-7-cyclohexylaminofluoran, 3-diethylamino-7-dibenzylaminofluoran, 3-diethylamino-7-n-octylaminofluoran, 3-diethylamino-7-phenylfluoran, 3-diethylamino-7-chlorofluoran, 3-diethylamino-6-chloro-7-methylfluoran, 3-diethylamino-6-methyl-7-
Chlorofluorane, 3-di-n-butylamino-6-methyl-7-chlorofluorane, 3-diethylamino-7
-(3,4-dichloroanilino) fluoran, 3-ethylamino-6-chlorofluoran, 3-cyclohexylamino-6-chlorofluoran, 3-diethylamino-
7-dibenzylaminofluoran, 3-di-n-butylamino-7- (2-chlorobenzylamino) fluoran, rhodamine B anilinolactam, rhodamine Bp
-Chloroanilinolactam and the like,

Examples of the spiro compound include 3-methylspirodinaphthopyran, 3-ethylspirodinaphthopyran,
Spiropyran compounds such as 3,3'-dichlorospirodinaphthopyran, 3-benzylspirodinaphthopyran, 3-methylnaphtho- (3-methoxybenzo) spiropyran, and 3-propylspirobenzopyran; 3 ', 6'-bis Diethylamino-5-diethylaminospiro (isobenzofuran-1,9'-fluoren) -3-one, 3 ',
Compounds having a fluorene skeleton, such as 6'-bisdimethylamino-5-dimethylaminospiro (isobenzofuran-1,9'-fluoren) -3-one; 3,3-bis-
[2- (4-methoxyphenyl) -2- (4-dimethylaminophenyl) ethenyl] vinylogas triarylmethane compounds such as 4,5,6,7-tetrachlorophthalide. These can be used alone or in combination of two or more.

The amount of the electron-donating dye precursor to be used in the heat-sensitive recording material of the present invention is 0.1 to 0.1. 01 to 3.0 g / m ² ,
More preferably, it is used in the range of about 0.03 to 2.0 g / m ² .

The electron-accepting developer used in the heat-sensitive recording material of the present invention is generally represented by an acidic substance, but is not particularly limited. For example, clay substances, phenol derivatives, aromatic carboxylic acids and their derivatives, N, N '
Urea derivatives such as -diarylthiourea and N-sulfonylurea, and polyvalent metal salts thereof can be used.

More specifically, clay materials such as acid clay, activated clay, zeolite, bentonite and kaolin, p-phenylphenol, p-hydroxyacetophenone, 4-
Hydroxy-4'-methyldiphenylsulfone, 4-hydroxy-4'-isopropoxydiphenylsulfone,
4-hydroxy-4'-benzenesulfonyloxydiphenyl sulfone, 1,1-bis (4-hydroxyphenyl) propane, 1,1-bis (4-hydroxyphenyl) pentane, 1,1-bis (4-hydroxyphenyl) Hexane, 1,1-bis (4-hydroxyphenyl) cyclohexane, 1,1-bis (4-hydroxyphenyl) cyclododecane, 2,2-bis (4-hydroxyphenyl) propane, 2,2-bis (4- (Hydroxyphenyl) hexane, 2,2-bis (4-hydroxyphenyl) octane, 1,1-bis (4-hydroxyphenyl) -2-ethylhexane, 2,2-bis (3-chloro-4-hydroxyphenyl) Propane, 1,1-bis (4-hydroxyphenyl) -1-phenylethane,
1,3-di- [2- (4-hydroxyphenyl) -2-
Propyl] benzene, 1,3-di- [2- (3,4-dihydroxyphenyl) -2-propyl] benzene,
4-di- [2- (4-hydroxyphenyl) -2-propyl] benzene, 4,4'-dihydroxydiphenyl ether, 4,4'-dihydroxydiphenylsulfone,
2,4'-dihydroxydiphenyl sulfone, 3,3 '
-Dichloro-4,4'-dihydroxydiphenylsulfone, 3,3'-diallyl-4,4'-dihydroxydiphenylsulfone, 3,3'-dichloro-4,4'-dihydroxydiphenylsulfide, 2,2-bis ( Methyl 4-hydroxyphenyl) acetate, butyl 2,2-bis (4-hydroxyphenyl) acetate, 4,4'-thiobis (2-t-butyl-5-methylphenol), benzyl p-hydroxybenzoate, p- Chlorobenzyl hydroxybenzoate, dimethyl 4-hydroxyphthalate, benzyl gallate, stearyl gallate, salicylanilide,
5-chlorosalicylanilide, novolak phenolic resin, modified terpene phenolic resin, 3,5-di-t-butylsalicylic acid, 3,5-di-t-nonylsalicylic acid,
3,5-didodecylsalicylic acid, 3-methyl-5-t-
Dodecyl salicylic acid, 5-cyclohexyl salicylic acid,
3,5-bis (α, α-dimethylbenzyl) salicylic acid, 3-methyl-5- (α-methylbenzyl) salicylic acid, and the like, and metal salts thereof such as zinc, nickel, aluminum, and calcium. In particular, compounds containing an alkyl group in the molecule are preferably used. These can be used alone or in combination of two or more.

The amount of the electron-accepting developer used in the heat-sensitive recording material of the present invention is selected depending on the type of the electron-accepting developer used. 50 to 2000% by weight, more preferably 80 to 15%
It is preferable to use it in the range of about 00% by weight.

As the diazo compound used in the heat-sensitive recording material of the present invention, a photo-decomposable aromatic diazonium compound is particularly preferable, and specifically, an aromatic diazonium salt,
And diazosulfonate compounds. 4-diethylaminobenzenediazonium, 2,5-dibutoxy-4-morpholinobenzenediazonium, 2,5-diethoxy-
Examples thereof include 4-tolylthiobenzenediazonium, 4-N-ethyl-N-hydroxyethylbenzenediazonium, and 3-methyl-4-pyrrolidinobenzenediazonium. These tetrafluoroborate salts, hexafluorophosphate salts and the like are preferred because of their high hydrophobicity. These can be used alone or in combination of two or more.

The amount of the diazo compound used in the heat-sensitive recording material of the present invention is 0.1 to 0.1. It is preferably used in the range of about 01 to 2.0 g / m ² , more preferably about 0.03 to 1.0 g / m ² .

As the coupler which reacts with the diazo compound used in the heat-sensitive recording material of the present invention to form a colored product, a hydroxy aromatic compound and an active methylene compound are preferable. Specifically, resorcin, phloroglysin, 1-hydroxynaphthalene , 2,3-dihydroxynaphthalene,
2,3-dihydroxy-6-sulfanylnaphthalene,
1,5-dihydroxynaphthalene, dihydroxybiphenyl, 2-hydroxy-3-naphthoic acid anilide, 2-
Hydroxy-3-naphthoic acid tetradecylamide, benzoylacetanilide, 1-phenyl-3-phenylacetamido-5-pyrazolone, and the like. These can be used alone or in combination of two or more.

The amount of the coupler which reacts with the diazo compound used in the heat-sensitive recording material of the present invention to form a colored product is 0.1 to 0.1%. 01 to 3.0 g / m ² , more preferably 0.04 to
It is preferable to use in the range of about 1.5 g / m ² .

When a diazo compound is used, it is preferable to add a basic compound to improve the reactivity. Specifically, organic amines such as tricyclohexylamine, guanidines such as 1,2-dicyclohexyl-3-phenylguanidine, ureas such as allyl urea and ethylene thiourea, imidazoles such as 4-phenylimidazole, and dibenzylpiperazine And the like, piperidines, amidines, pyrroles, morpholines and the like. These can be used alone or in combination of two or more.

The isocyanate compound used in the heat-sensitive recording material of the present invention is preferably a solid colorless or pale-colored aromatic isocyanate compound or heterocyclic isocyanate compound having one or more isocyanate groups in the molecule and solid at room temperature. .

Specifically, examples of isocyanate compounds include 2,6-dichlorophenyl isocyanate, p
-Chlorophenyl isocyanate, 1,3-phenylene diisocyanate, 1,4-phenylene diisocyanate, 1,3-dimethylbenzene-4,6-diisocyanate, 1,4-dimethylbenzene-2,5-di Isocyanate, 1-methoxybenzene-2,4-diisocyanate, 1-methoxybenzene-2,5-diisocyanate, 1-ethoxybenzene-2,4-diisocyanate, 2,5-dimethoxybenzene-1 2,4-diisocyanate, 2,5-diethoxybenzene-1,4-diisocyanate, 2,5-dibutoxybenzene-1,4-diisocyanate, azobenzene-4,4'-diisocyanate, Diphenyl ether-4,4'-diisocyanate, naphthalene-1,4-diisocyanate, naphthalene-1,5-dii Cyanate, naphthalene-2,6
-Diisocyanates, naphthalene-2,7-diisocyanates,

3,3'-dimethylbiphenyl-4,4 '
-Diisocyanate, 3,3'-dimethoxybiphenyl-4,4'-diisocyanate, 3,3'-dichlorobiphenyl-4,4'-diisocyanate, 2,2 ',
5,5'-tetrachlorobiphenyl-4,4'-diisocyanate, diphenylmethane-4,4'-diisocyanate, diphenyldimethylmethane-4,4'-diisocyanate, benzophenone-3,3'-di Isocyanate, fluorene-2,7-diisocyanate, anthraquinone-2,6-diisocyanate, 9-ethylcarbazole-3,6-diisocyanate, pyrene-3,8
Diisocyanate, naphthalene-1,3,7-triisocyanate, biphenyl-2,4,4'-triisocyanate, 4,4 ', 4 "-triisocyanatotriphenylamine, 4,4', 4 "-triisocyanate-
2,5-dimethoxytriphenylamine, p-N, N-
Dimethylaminophenyl isocyanate, 5,7-diisocyanate-1,1-dimethyl-6-n-propylindane, 5,7-diisocyanate-1,1,4,6-
Tetramethylindane, tris (4-phenylisocyanate) thiophosphate, and the like.

If necessary, these isocyanate compounds may be used as so-called block isocyanates, which are addition compounds with phenols, lactams, oximes and the like, and may be used as dimer diisocyanates. For example, diisomer and trimer of 1-methylbenzene-2,4-diisocyanate may be used as isocyanurate. Furthermore, reacted with various polyols and the like,
For example, polyisocyanate obtained by reacting tolylene diisocyanate with trimethylolpropane can be used. In addition, the isocyanate compound includes dimers of block isocyanate and diisocyanate and 3 isocyanates.
The monomer and the polyisocyanate may be used alone or in combination of two or more.

The imino compound used in the heat-sensitive recording material of the present invention, which reacts with an isocyanate compound upon heating to form a colored body, contains one or more imino groups in the molecule. And the like.

3-iminoisoindoline-1-one, 3
-Imino-4,5,6,7-tetrachloroisoindoline-1-one, 3-imino-4,5,6,7-tetrabromoisoindoline-1-one, 3-imino-4,5
6,7-tetrafluoroisoindoline-1-one, 3
-Imino-5,6-dichloroisoindoline-1-one, 3-imino-4,5,7-trichloro-6-methoxyisoindoline-1-one, 3-imino-4,5,7
-Trichloro-6-methylmercaptoisoindoline-
1-one, 3-imino-6-nitroisoindoline-1
-One, 3-iminoisoindoline-1-spiro-dioxolan, 1,1-dimethoxy-3-iminoisoindoline, 1,1-diethoxy-3-imino-4,5,6,
7-tetrachloroisoindoline, 1-ethoxy-3-
Iminoisoindoline, 1,3-diiminoisoindoline, 1,3-diimino-4,5,6,7-tetrachloroisoindoline, 1,3-diimino-6-methoxyisoindoline, 1,3-diimino- 6-cyanoisoindoline, 1,3-diimino-4,7-dithia-5,5,
6,6-tetrahydroisoindoline, 1-iminonaphthalimide, 1-iminodiphenimide, 1-phenylimino-3-iminoisoindoline,

7-amino-2,3-dimethyl-5-oxopyrrolo [3,4b] pyrazine, 7-amino-2,3-
Diphenyl-5-oxopyrrolo [3,4b] pyrazine,
1- (2'-cyano-4'-nitrophenylimino)-
3-iminoisoindoline, 1- (2'-chloro-5 '
-Cyanophenylimino) -3-iminoisoindoline, 1- (2 ', 6'-dichloro-4'-nitrophenylimino) -3-iminoisoindoline, 1- (3'-
Chlorophenylimino) -3-iminoisoindoline,
1- (2 ', 5'-dichlorophenylimino) -3-iminoisoindoline, 1- (2', 4 ', 5'-trichlorophenylimino) -3-iminoisoindoline,
-(2 ', 5'-dimethoxyphenylimino) -3-iminoisoindoline, 1- (2', 5'-diethoxyphenylimino) -3-iminoisoindoline, 1-
(2'-methyl-4'-nitrophenylimino) -3-
Iminoisoindoline, 1- (5'-chloro-2'-phenoxyphenylimino) -3-iminoisoindoline, 1- (4'-N, N-dimethylaminophenylimino) -3-iminoisoindoline, 1- (2'-methoxy-5'-N-phenylcarbamoylphenylimino)
-3-iminoisoindoline, 1- (6'-methylbenzothiazolyl-2'-imino) -3-iminoisoindoline,

1- (3'-dimethylamino-4'-methoxyphenylimino) -3-iminoisoindoline, 1
-(2'-chloro-5'-trifluoromethylphenylimino) -3-iminoisoindoline, 1- (5 ',
6'-dichlorobenzothiazolyl-2'-imino) -3
-Iminoisoindoline, 1- (4'-phenylaminophenylimino) -3-iminoisoindoline, 1-
(P-phenylazophenylimino) -3-iminoisoindoline, 1- (naphthyl-1'-imino) -3-iminoisoindoline, 1- (anthraquinone-1'-imino) -3-iminoisoindoline, 1- (5'-chloroanthraquinone-1'-imino) -3-iminoisoindoline, 1- (N-ethylcarbazolyl-3'-imino) -3-iminoisoindoline, 1- (naphthoquinone-1 '-Imino) -3-iminoisoindoline, 1-
(Pyridyl-4'-imino) -3-iminoisoindoline, 1- (benzimidazolone-6'-imino) -3-
Iminoisoindoline, 1- (1'-methylbenzimidazolone-6'-imino) -3-iminoisoindoline, 1- (7'-chlorobenzimidazolone-5'-imino) -3-iminoisoindoline, 1- (benzimidazolyl-2'-imino) -3-imino-4,7-dithiatetrahydroisoindoline,

1- (benzimidazolyl-2'-imino) -3-iminoisoindoline, 1- (benzimidazolyl-2'-imino) -3-imino-4,5,6,7
-Tetrachloroisoindoline, 1- (2 ', 4'-dinitrophenylhydrazone) -3-iminoisoindoline, 1- (indazolyl-3'-imino) -3-iminoisoindoline, 1- (indazolyl-3' -Imino)
-3-imino-4,5,6,7-tetrabromoisoindoline, 1- (indazolyl-3'-imino) -3-imino-4,5,6,7-tetrafluoroisoindoline, 1- (4 ', 5'-dicyanoimidazolyl-2'-
Imino) -3-imino-5,6-dimethyl-4,7-pyradiisoindolin, 1- (cyanobenzoylmethylene) -3-iminoisoindoline, 1- (cyanocarbonamidomethylene) -3-iminoisoindoline , 1-
(Cyanocarbomethoxymethylene) -3-iminoisoindoline, 1- (cyanocarboethoxymethylene) -3
-Iminoisoindoline, 1- (cyano-N-phenylcarbamoylmethylene) -3-iminoisoindoline,
1- [cyano-N- (3′-methylphenyl) carbamoylmethylene] -3-iminoisoindoline, 1- [cyano-N- (4′-chlorophenyl) carbamoylmethylene] -3-iminoisoindoline,

1- [cyano-N- (4'-methoxyphenyl) -carbamoylmethylene] -3-iminoisoindoline, 1- (cyano-p-nitrophenylmethylene)
-3-iminoisoindoline, 1- [cyano-N-
(3'-chloro-4'-methylphenyl) -carbamoylmethylene] -3-iminoisoindoline, 1- (dicyanomethylene) -3-iminoisoindoline, 1- (cyano-1 ', 2', 4'- Triazolyl- (3 ')-carbamoylmethylene) -3-iminoisoindoline, 1
-(Cyanothiazoyl-2'-carbamoylmethylene)
-3-iminoisoindoline, 1- (cyanobenzimidazolyl-2'-carbamoylmethylene) -3-iminoisoindoline, 1- (cyanobenzothiazolyl-2 '
-Carbamoylmethylene) -3-iminoisoindoline, 1- [cyanobenzimidazolyl-2'-methylene] -3-iminoisoindoline, 1- [cyanobenzimidazolyl-2'-methylene] -3-imino-4,
5,6,7-tetrachloroisoindoline, 1- [cyanobenzimidazolyl-2'-methylene] -3-imino-5-methoxyisoindoline, 1- [cyanobenzimidazolyl-2'-methylene] -3-imino -6-chloroisoindoline,

1- [Cyanobenzimidazolyl-2'-
Methylene] -3-imino-4,7-dithiatetrahydroisoindoline, 1-[(1'-phenyl-3'-methyl-5-oxo) -pyrazolidene-4 ']-3-iminoisoindoline, 1- [Cyanobenzimidazolyl-
2'-methylene] -3-imino-5,6-dimethyl-
4,7-pyradioisoindoline, 1-[(1′-methyl-3′-n-butyl) -barbituric acid-5 ′]-3-iminoisoindoline, 3-imino-1-sulfobenzoic imide, 3-imino-1-sulfo-6-chlorobenzoimide, 3-imino-1-sulfo-5,6-dichlorobenzoimide, 3-imino-1-sulfo-6-nitrobenzoimide, 3-imino -1-sulfo-6-methoxybenzoic acid imide, 3-imino-1-sulfo-4,5,7
-Trichloro-6-methylmercaptobenzoic imide,
3-imino-1-sulfonaphthoic imide, 3-imino-1-sulfo-5-bromonaphthoic imide, and 3-
And imino-2-methyl-4,5,6,7-tetrachloroisoindoline-1-one.

The amount of the isocyanate compound used in the heat-sensitive recording material of the present invention is usually 0.1 to 2.0 g / m ² as the isocyanate compound.
From ² to 1.5 g / m ² is preferred for obtaining a high color density.
The amount of the electron-donating dye precursor or imino compound is suitably from 10 to 300% by weight, preferably from 20 to 250% by weight, based on the isocyanate compound.

In order to include the reactant and the co-reactant used in the present invention in the heat-sensitive recording layer, the reactant and the co-reactant may be contained in the coating solution or ink for the heat-sensitive recording layer. As a method to be contained in a liquid or ink, a method in which each compound is dissolved in a solvent alone or dispersed in a dispersion medium and then mixed, a method in which each compound is mixed and then dissolved in a solvent or dispersed in a dispersion medium, There is a method in which each compound is heated and dissolved to homogenize, then cooled and then dissolved in a solvent or dispersed in a dispersion medium, but is not particularly limited. If necessary, a dispersing aid may be used for dispersion. When water is used as the dispersion medium, examples of the dispersion aid include water-soluble polymers such as polyvinyl alcohol and various surfactants. Further, a water-soluble organic solvent such as ethanol may be mixed. When an organic solvent typified by hydrocarbons is used as a dispersion medium, lecithin, phosphates, and the like may be used as a dispersion aid.

The average particle size of the reactants and co-reactants constituting the heat-sensitive recording layer must be 7 μm or less.
It is preferably from 0.1 to 5 μm, particularly preferably from 0.1 to 2 μm. If the average particle diameter is 7 μm or more, light scattering is likely to occur, and it is difficult to see a clear watermark pattern.

Further, it is possible to add a binder to the heat-sensitive recording layer for the purpose of improving the strength of the heat-sensitive recording layer. Specific examples of the binder include starches, hydroxyethylcellulose, methylcellulose, carboxymethylcellulose, gelatin, casein, polyvinyl alcohol, modified polyvinyl alcohol, sodium polyacrylate, acrylamide / acrylate copolymer, acrylamide / acryl. Water-soluble polymers such as acid ester / methacrylic acid terpolymer, alkali salt of styrene / maleic anhydride copolymer, alkali salt of ethylene / maleic anhydride copolymer, polyvinyl acetate, polyurethane, polyacrylic acid Ester, styrene / butadiene copolymer, acrylonitrile / butadiene copolymer, methyl acrylate / butadiene copolymer, ethylene / vinyl acetate copolymer, ethylene / vinyl chloride copolymer, polyvinyl chloride, ethylene Vinylidene chloride copolymers, such as latex, such as polyvinylidene chloride and the like, but not particularly limited thereto, and these can be used singly or a plurality.

Further, a sensitizer can be contained in the heat-sensitive recording layer as an additive for adjusting the color-forming sensitivity of the heat-sensitive recording layer. These compounds preferably have a melting point of 60 ° C to 200 ° C, particularly preferably compounds having a melting point of 80 ° C to 180 ° C. Including these, sensitizers used in general thermosensitive recording paper can be used. These compounds include waxes such as N-hydroxymethyl stearamide, behenamide, stearamide, palmitamide, naphthol derivatives such as 2-benzyloxynaphthalene, p-benzylbiphenyl, 4-allyloxybiphenyl Biphenyl derivatives such as 1,2-bis (3-methylphenoxy) ethane,
Polyether compounds such as 2,2'-bis (4-methoxyphenoxy) diethyl ether and bis (4-methoxyphenyl) ether; carbonic acid such as diphenyl carbonate, dibenzyl oxalate and bis (p-methylbenzyl) oxalate; Oxalic acid diester derivatives;
More than one species can be added in combination.

The support used in the heat-sensitive recording material of the present invention, in which the optical density is partially formed, is transparent or translucent paper or paper as long as the optical density is not lost.
Various kinds of nonwoven fabrics, woven fabrics, synthetic resin films such as polyethylene terephthalate and polypropylene, and synthetic resins such as polyethylene and polypropylene may be laminated or laminated. In this case, especially the lamination,
Alternatively, when an aqueous liquid for forming a heat-sensitive recording layer is applied to a laminated film or the like, if the heat-sensitive recording layer is difficult to apply because the hydrophilicity of the film or the like is small, a surface hydrophilic treatment by corona discharge or a binder may be used. A treatment such as applying the same water-soluble polymer as used for the above to the surface of the support is also effective.

A protective layer can be provided on the uppermost layer of the heat-sensitive recording material of the present invention in order to improve printability and heat resistance.

When a protective layer is provided on the heat-sensitive recording material of the present invention, the protective layer is formed mainly of a material such as a water-soluble polymer and latex. In this case, a hardener such as a compound having an epoxy group or a zirconium salt or a crosslinking agent may be added. In addition, a protective layer may be formed by applying and curing a light and electron beam curable resin or a thermosetting resin. Further, a protective film may be formed by laminating a plastic film. Further, a pigment or the like may be added in order to further improve the writing property and the running property. The average particle size of the pigment used for the protective layer is preferably 2.0 μm or less in order to reproduce the optical density of the support and to increase the image density.
The coating amount of the protective layer is 0.2 to 10 g / m ² , preferably 1
５5 g / m ² , and may be two or more layers as necessary.

Specific examples of the resin used for forming the protective layer include starches, hydroxyethylcellulose, methylcellulose, ethylcellulose, carboxymethylcellulose, gelatin, casein, polyvinyl alcohol, modified polyvinyl alcohol, polyacrylic acid, polymethacrylic acid, and polymethacrylic acid. Acrylate, polymethacrylate, sodium polyacrylate, polyethylene terephthalate, polybutylene terephthalate, chlorinated polyether, allyl resin, furan resin, ketone resin, oxybenzoyl polyester, polyacetal, polyetheretherketone, polyethersulfone, Polyimide, polyamide, polyamideimide, polyaminobismaleimide, polymethylpentene, polyphenylene oxide, polyphenylene Nsurufido, polyphenylene sulfone, polysulfone, polyarylate, polyallyl sulfone, polybutadiene, polycarbonate, polyethylene, polypropylene, polystyrene, polyvinyl chloride,
Polyvinylidene chloride, polyvinyl acetate, polyurethane,
Phenolic resin, urea resin, melamine resin, melamine formalin resin, benzoguanamine resin, bismaleimide triazine resin, alkyd resin, amino resin, epoxy resin, unsaturated polyester resin, styrene / butadiene copolymer, acrylonitrile / butadiene copolymer,
Methyl acrylate / butadiene copolymer, ethylene / vinyl acetate copolymer, acrylamide / acrylate ester copolymer, acrylamide / acrylate / methacrylic acid terpolymer, styrene / maleic anhydride copolymer Examples thereof include an alkali salt of a polymer, an alkali salt or an ammonium salt of an ethylene / maleic anhydride copolymer, and various other polyolefin-based resins. These can be used alone or in combination of two or more.

Further, in the heat-sensitive recording material of the present invention, a water-soluble polymer, a white or colored dye or pigment may be provided between the heat-sensitive recording layer and the protective layer or between the heat-sensitive recording layer and the support, if necessary.
An intermediate layer containing any one or more of the hollow particles may be provided. However, in this case, the haze value is preferably not more than 80% not only for the heat-sensitive recording layer but also for the entire layer provided on the support such as the intermediate layer and the protective layer. The protective layer and / or the intermediate layer may be composed of two or three or more layers. The heat-sensitive recording layer may be a multilayer of two or more layers by containing each component one by one or changing the mixing ratio for each layer. Further, in the heat-sensitive recording layer and / or
Alternatively, a material on which information can be recorded electrically, optically, and magnetically may be included on the surface opposite to the surface on which the other layer and / or the heat-sensitive recording layer is provided. Further, a back coat layer may be provided on the surface opposite to the surface on which the heat-sensitive recording layer is provided for the purpose of preventing blocking, curling, and preventing electrification.

In the heat-sensitive recording material of the present invention, an intermediate layer can be provided between a support and a layer adjacent to the support, if necessary, in order to obtain smoothness and heat insulation. The amount of smear when this intermediate layer is provided is preferably 0.5 to 30 g / m ² ,
More preferably, it is 1 to 10 g / m ² , and it may be a multilayer of two or more layers.

As the binder used for the intermediate layer, conventionally known latexes and water-soluble polymers can be used. That is, latexes include styrene / butadiene latex, acrylonitrile / butadiene / styrene latex, vinyl acetate resin, vinyl acetate / acrylate copolymer, styrene / acrylate copolymer, acrylate resin, and polyurethane resin Etc. can be used. Examples of the water-soluble polymer include polyvinyl alcohol, starch and derivatives thereof, cellulose derivatives such as hydroxyethyl cellulose, carboxymethyl cellulose, methyl cellulose, and ethyl cellulose, sodium polyacrylate, polyvinyl pyrrolidone, acrylamide / acrylate copolymer, acrylamide / Acrylic ester / methacrylic acid copolymer, styrene / maleic anhydride copolymer alkali salt, polyacrylamide, sodium alginate, gelatin, casein, and the like can be used.

The heat-sensitive recording layer and / or the protective layer and / or the intermediate layer include silica, diatomaceous earth, talc, kaolin, calcined kaolin, calcium carbonate, magnesium carbonate, magnesium hydroxide, titanium oxide, zinc oxide, and oxide. Inorganic pigments such as silicon and aluminum hydroxide, and organic pigments such as styrene / acrylic resin, polystyrene resin, acrylic resin, polyethylene resin, polypropylene resin, and urea-formalin resin can be used. In addition, inorganic and organic pigments having pores, hollow particles, expandable hollow particles, and air capsules containing air inside can also be used. Must be used within a range that does not cause the disappearance. Higher fatty acid metal salts such as zinc stearate and calcium stearate, waxes such as paraffin, paraffin oxide, polyethylene, polyethylene oxide, stearamide, caster wax and the like, and dioctyl sulfosuccinic acid for the purpose of preventing head wear and sticking. A dispersant such as sodium, a surfactant, a fluorescent dye, and the like can be contained.

Each layer in the present invention is laminated on a support,
The method for forming the heat-sensitive recording material of the present invention is not particularly limited, and it can be formed by a conventional method. For example, a smearing device such as an air knife coater, a blade coater, a bar coater, a curtain coater, and the like, various printing machines by a system such as lithographic, letterpress, intaglio, flexo, gravure, screen, and hot melt can be used. Further, each layer can be held by UV irradiation and EB irradiation in addition to the usual drying step.

[0065]

The present invention will be described in more detail with reference to the following examples. The present invention is not limited to these examples. The percentages and parts shown below are% by weight and parts by weight, respectively.

Example 1 A 1: 1 mixture of bleached hardwood kraft pulp (LBKP) and softwood bleached kraft pulp (NBKP) was dispersed in water at a concentration of 4%, and the freeness was determined using a double disc refiner. The mixture was beaten to 300 ml with a Canadian Standard Freeness Tester. This pulp slurry contains 10% of light calcium carbonate as filler and 0.3% of pulp with alkyl ketene dimer as sizing agent.
Polyacrylamide as a strength enhancer vs. pulp 0.5
% And cationized starch to pulp were added to 1.0%, and diluted with water to obtain a 1% slurry. This slurry is called MITS
Using a dandy roll provided with UBISHI and a transparent character, paper making is performed by a fourdrinier paper machine so as to have a basis weight of 70 g / m ² , and a transparent paper support used for the heat-sensitive recording material of the present invention is prepared. Manufactured.

Example 2 3-Dibutylamino-6 was used as an electron-donating dye precursor.
Dye precursor dispersion obtained by pulverizing 100 parts of -methyl-7-anilinofluoran with 250 parts of a 2% aqueous polyvinyl alcohol solution by a paint conditioner, and 1,1-bis (4-hydroxyl as an electron-accepting developer. An electron-accepting developer dispersion obtained by pulverizing 100 parts of phenyl) cyclohexane with 250 parts of a 2% aqueous polyvinyl alcohol solution by a paint conditioner, and 150 parts of 2-benzyloxynaphthalene as a heat-fusible compound in 2%
A thermally fusible compound dispersion obtained by pulverizing with a paint conditioner together with 350 parts of an aqueous polyvinyl alcohol solution, 900 parts of a 30% dispersion of calcium carbonate, 170 parts of a 30% dispersion of zinc stearate, and further 10% of polyvinyl alcohol The heat-sensitive coating liquid obtained by thoroughly mixing 1250 parts of the aqueous solution was smeared onto the transparent paper support having a basis weight of 70 g / m ² prepared in Example 1 so that the smear amount was 2.1 g / m ^2, and dried. A heat-sensitive recording material was obtained.

Example 3 A heat-sensitive coating solution was prepared in the same manner as in Example 2, and the amount of smear was 4.3 g / m ² on the transparent paper support having a basis weight of 70 g / m ² prepared in Example 1. The resultant was smeared and dried to obtain a heat-sensitive recording material.

Example 4 As an electron-donating dye precursor, 3- (4-dimethylamino-2-ethoxyphenyl) -3- (1-ethyl-2-
Methylindol-3-yl) -4-azaphthalide 10
0 parts of the dye precursor dispersion obtained by pulverizing with a paint conditioner together with 250 parts of a 2% aqueous solution of polyvinyl alcohol, and N-stearyl-N'- as an electron-accepting developer.
(4-Hydroxyphenyl) urea dispersion liquid obtained by pulverizing 250 parts of urea with 625 parts of a 2% aqueous polyvinyl alcohol solution using a paint conditioner,
2-benzyloxynaphthalene 1 as a heat-fusible compound
50 parts of a heat-fusible compound dispersion obtained by pulverizing with a paint conditioner together with 350 parts of a 2% aqueous polyvinyl alcohol solution, and a 30% dispersion of calcium carbonate 9
70 parts by weight of the heat-sensitive coating liquid prepared in Example 1 prepared by thoroughly mixing 00 parts, 170 parts of a 30% dispersion of zinc stearate, and 1300 parts of a 10% aqueous solution of polyvinyl alcohol.
/ M ^{2 on} a transparent paper support to give a smear amount of 4.9 g / m ² and dried to obtain a heat-sensitive recording material.

Example 5 A heat-sensitive coating solution was prepared in the same manner as in Example 4, and the amount of smear was 7.0 g / m ² on the transparent paper support having a basis weight of 70 g / m ² prepared in Example 1. The resultant was smeared and dried to obtain a heat-sensitive recording material.

Example 6 A heat-sensitive coating liquid was prepared in the same manner as in Example 3, and the amount of smear was 11.6 g / m ² on the transparent paper support having a basis weight of 70 g / m ² prepared in Example 1. The resultant was smeared and dried to obtain a heat-sensitive recording material.

Example 7 30 parts of 4,4 ', 4 "-triisocyanato-2,5-dimethoxytriphenylamine which is an aromatic isocyanate compound was added to a 10% aqueous solution of polyvinyl alcohol 30
And 40 parts of water are mixed and pulverized with a paint conditioner to obtain an isocyanate compound dispersion or an imino compound of 1,3-diimino-4,5,6,7
-30 parts of tetrachloroisoindoline, 30 parts of a 10% aqueous solution of polyvinyl alcohol, and 40 parts of water are mixed,
Imino compound dispersion obtained by pulverizing with a paint conditioner, 30% dispersion of magnesium carbonate 200
Of a 10% aqueous polyvinyl alcohol solution and 250 parts of water, the heat-sensitive coating liquid was coated on the transparent paper support having a basis weight of 70 g / m ² prepared in Example 1 with a spread amount of 3.3 g. / M ² and dried to obtain a heat-sensitive recording material.

Comparative Example 1 A heat-sensitive coating liquid was prepared in the same manner as in Example 2, and the obtained heat-sensitive coating liquid was applied to a non-transparent high-quality paper having a basis weight of 70 g / m ^{2 at} a coating amount of 15.3 g / m ^2. A thermosensitive recording material was obtained in the same manner as in Example 2 except that the smearing and drying were carried out as follows.

Test 1. (Coloring performance) The thermal recording materials produced in Examples 2 to 7 and Comparative Example 1 were printed using a thermal facsimile printing tester (TH-PMD) manufactured by Okura Electric with a thermal head (LH4409) manufactured by TDK. The density of the resulting color image was measured using a densitometer (Macbeth RD918, spectral characteristics blue).
All showed an optical density of 1.0 or more.

Test 2 (Haze value of heat-sensitive recording layer) The coating liquid for the heat-sensitive recording layer of Examples 2 to 7 and Comparative Example 1 has a thickness of 12
A haze value of a sample having a smear dried on a 0 μm PET film and a cellotape adhered to the surface was measured using a haze meter. The results are shown in Table 1.

Test 3. (Visual Confirmation of Transparency Pattern) The heat-sensitive recording materials of Examples 2 to 7 and Comparative Example 1 were subjected to transmitted light.
The characters of MITSUBISHI, which are transparent patterns on the support, were visually confirmed.

[0077]

[Table 1]

[0078]

As described above, by using a paper support with a watermark as a support for the heat-sensitive recording material, the production is easy, and no special light source is required. As a result of being able to judge the authenticity only by observation, it is possible to obtain a highly practical thermosensitive recording material having excellent anti-counterfeiting properties.

Claims (4)

[Claims] 1. A heat-sensitive recording layer mainly containing a reactant and a co-reactant which reacts with the reactant when heated to form a colored body on a support partially formed with optical shading. Heat-sensitive recording material. 2. A support in which optical shading is partially formed is a transparent support, and a reactant provided on the support and a reaction with the reactant upon heating to form a colored body Haze value of the heat-sensitive recording layer mainly containing the
2. The heat-sensitive recording material according to claim 1, wherein: 3. The reactant is an electron donating dye precursor,
3. The heat-sensitive recording material according to claim 1, wherein the coreactant is an electron-accepting developer. 4. The heat-sensitive recording material according to claim 1, wherein the reactant is an isocyanate compound.