JPH1148618A - Thermosensible recording material - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a thermosensible recording material having an excellent preservability by the use of a specific compound having a hydroxyphenyltriazine construction as a developer. SOLUTION: The thermosensible material contains at least one kind of compounds indicated by formula. In the formula, Z represents O, S or-NR-(R represents H or an alkyl group of 1-8C), Z<1> and Z<2> represents respectively independently direct combination, O, S or-NR-(R represents H or an alkyl group of 1-8C). A and B represent respectively independently an alkyl group of 1-20C, an aryl group capable of containing a substituent of 6-30C, cycloalkyl group, and an acyl group. X and Y represent respectively independently H, a hydroxyl group, an alkyl group of 1-8C, a cycloalkyl group, an aryl group of 6-12C, an alkylaryl group, and an aryl alkyl group.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION The present invention relates to a heat-sensitive recording material such as facsimile paper, printer paper, labels, price tags, tickets, etc., and more particularly to a compound having a hydroxyphenyltriazine structure in a heat-sensitive recording layer. The present invention relates to a thermosensitive recording material having improved storage stability such as heat resistance, light resistance and oil resistance.

[0002]

2. Description of the Related Art A heat-sensitive recording material is usually composed of a colorless or pale-colored color-forming substance and a color developer which forms a color-forming substance under the action of heat. And other additives together with a support such as paper, synthetic paper, plastic film or sheet. And
In a recording apparatus, when a heating element such as a thermal head or a hot pen comes into contact, a color-forming substance reacts with a color developer to form a black color or the like for recording. Such a recording material does not require complicated processing such as development and fixing as compared with other recording materials, and can be recorded in a relatively simple apparatus and in a short time. Due to its advantages such as low environmental pollution and low cost, it is used not only for copying books and documents, but also for various measurement recording paper, computers, facsimile machines, telex, vending machines such as ticket, prepaid Widely used as recording material for cards, labels, etc.

[0003] In a conventional heat-sensitive recording material, an initial combination of a color-forming substance (leuco dye), a developer for thermally developing the color-forming substance and a sensitizer to be used as necessary is used. From the viewpoints of color development sensitivity and background soiling (background fogging), practically satisfactory ones have been obtained.

However, when these heat-sensitive recording materials are stored in a bag made of polyvinyl chloride or come into contact with a desk mat made of vinyl chloride, or when the heat-sensitive recording material is touched by hand, There was a disadvantage that the color-developed portion was decolored by the contained plasticizer and sebum.

Further, when these heat-sensitive recording materials are exposed to sunlight or lighting for a long period of time, not only does the printed portion become faint or disappear, but also the background portion becomes yellowish. If a printout such as a receiving paper, a word processor, or a personal computer is left on a desk, the recorded image becomes unclear and there is a problem in document storage.

The use of a compound having a hydroxyphenyl structure as a developer has been known in the art, and for example, a polyhydric phenol compound such as bisphenol A is usually used. Although these phenolic compounds produce color, they are not satisfactory in the stability of a color image, and in particular, they are not satisfactory in oil resistance. Since the storability limits the range of use of the sensible heat recording material, improvement of the storability has been desired.

[0007] JP-A-61-254487 and JP-A-2-293181 describe the use of a compound having a triazine structure as a heat-sensitive recording material. However, none of these was satisfactory in the initial color development and storage stability.

Accordingly, an object of the present invention is to provide a heat-sensitive recording material having excellent storage stability such as heat resistance, oil resistance and light resistance.

[0009]

Means for Solving the Problems The present inventors have made intensive studies in view of the above situation, and as a result, have achieved the above object by using a specific compound having a hydroxyphenyltriazine structure as a color developer. It was found that it could be done.

The present invention has been made based on the above-mentioned findings, and it is intended that at least one compound represented by the following general formula (I) of the following formula (I) is contained. Another object of the present invention is to provide a heat-sensitive recording material.

[0011]

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[0012]

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, the heat-sensitive recording material of the present invention will be described in detail.

The compound represented by formula (I) used in the present invention is used as a color developer.
In the general formula (I), examples of the alkyl group having 1 to 20 carbon atoms represented by A and B include methyl, ethyl, propyl, isopropyl, butyl, sec-butyl, tert-butyl, isobutyl, amyl, Amyl, hexyl, heptyl, octyl, isooctyl, tertiary octyl, 2-ethylhexyl, nonyl, isononyl, decyl, undecyl, dodecyl, tridecyl, tetradecyl, pentadecyl, hexadecyl, heptadecyl, octadecyl, nonadecyl, etc. Include cyclopentyl, cyclohexyl and the like, and the acyl group includes an aliphatic acyl group such as acetyl, propionyl and palmitoyl, and an aromatic acyl group such as benzoyl, toluoyl and salicyloyl;
Examples of the aryl group include phenyl, diphenyl, naphthyl, 2-methylphenyl, 4-methylphenyl, 2-hydroxyphenyl, 3-hydroxyphenyl, 4-hydroxyphenyl, 2,4-dihydroxyphenyl,
Methyl-4-hydroxyphenyl, 4-methoxyphenyl, 4-isopropoxy-2-hydroxyphenyl and the like can be mentioned. In particular, it is preferable to use a compound in which A and B are hydroxyphenyl groups because they are excellent in color development sensitivity and oil resistance.

The alkyl group having 1 to 8 carbon atoms represented by R includes methyl, ethyl, propyl, isopropyl, butyl, sec-butyl, tert-butyl, isobutyl, amyl, tertiary amyl, hexyl, heptyl. Octyl, isooctyl, tertiary octyl, 2-ethylhexyl and the like.

It is preferable to use a compound in which Z, Z ¹ and Z ² are an oxygen atom or a sulfur atom because they are excellent in color sensitivity and oil resistance.

Further, the number of carbon atoms represented by X and Y is 1
Examples of the alkyl group of No. 8 to No. 8 include methyl, ethyl, propyl, butyl, pentyl, hexyl, heptyl, octyl and the like, and examples of the cycloalkyl group include cyclopentyl, cyclohexyl and the like.
Examples of the aryl group to -12 include phenyl and naphthyl, and examples of the alkylaryl group include methylphenyl, dimethylphenyl and ethylphenyl. Examples of the arylalkyl group include phenylmethyl and
-Phenyl-1-methylethyl and the like.

Specific typical examples of the compound represented by the above general formula (I) (compound having a hydroxyphenyltriazine structure) include the following compounds No. 1 to No. 17 shown in [Chemical Formula 3] to [Chemical Formula 17]. 15 and others.

[0018]

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[0019]

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[0020]

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[0021]

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[0022]

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[0023]

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[0024]

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[0025]

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[0026]

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[0027]

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[0028]

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[0029]

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[0030]

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[0031]

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[0032]

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The method for synthesizing the compound represented by the general formula (I) is not particularly limited. For example, a phenol having a reactive substituent such as resorcinol or mercaptophenol and cyanuric chloride are used. Compounds No. 1 and No. 5 can be easily obtained by reacting with a catalyst such as potassium chloride.

[Synthesis Examples] Specific synthesis examples of the compound represented by the above general formula (I) according to the present invention are shown below. However, the present invention is not limited at all by the following synthesis examples.

Synthesis of Compound No. 5 15.7 g (0.12 mol) of 4-mercaptophenol, 7.38 g (0.04 mol) of cyanuric chloride, 22 g (0.16 mol) of potassium carbonate and 100 ml of acetone
And refluxed for 3 hours. After filtration, the filtrate was desolvated, dissolved in ethyl acetate, washed with water, dehydrated, and desolvated. The obtained liquid was recrystallized from toluene to obtain 11.2 g (yield: 62%) of a white solid having a melting point of 227 ° C.

The obtained compound was analyzed by infrared spectroscopy.
The following absorption was shown. ^{3350cm -1, 1720cm -1, 1690cm -1} , 1600cm -1, 1580cm -1,
^{1490cm -1, 1480cm -1, 1460cm -1} , 1440cm -1, 1360cm -1,
^{1240cm -1, 1160cm -1, 1100cm -1} , 1040cm -1, 1010cm -1,
970 cm ^-1 , 840 cm ^-1

Synthesis of Compound No. 7 3.9 g (0.031 mol) of 4-mercaptophenol, 4.8 g of 2,4-dichloro-6- (4-ethoxynaphthalene) -1,3,5-triazine (0 g) 0.015 mol) and 4.4 g (0.032 mol) of potassium carbonate were dissolved in 50 ml of acetone and refluxed for 3 hours. After filtration, the filtrate was desolvated, dissolved in ethyl acetate, washed with water, dehydrated, and desolvated. The obtained liquid was recrystallized from toluene to give a melting point of 2
4.4 g (58% yield) of a pale yellow solid at 15 ° C was obtained.

The obtained compound was analyzed by infrared spectroscopy.
The following absorption was shown. ^{3350cm -1, 2980cm -1, 1690cm -1} , 1600cm -1, 1580cm -1,
^{1500cm -1, 1460cm -1, 1420cm -1} , 1360cm -1, 1340cm -1,
^{1320cm -1, 1260cm -1, 1230cm -1} , 1160cm -1, 1090cm -1,
1070cm ^-1, 1020cm ^-1

The amount of the compound represented by the above general formula (I) is particularly limited because it varies depending on the required performance and recording suitability, the type and amount of the color-forming substance or other additives used together. Although not always done,
0.01 to 10 parts by weight, preferably 0.1 to 5 parts by weight, is used per 1 part by weight of the color-forming dye. When the amount is less than 0.01 part by weight per 1 part by weight of the chromogenic dye, the coloring density is low, and when it exceeds 10 parts by weight, the effect is not further increased and it is uneconomical.

In the present invention, a colorless or light-colored color-forming substance is generally used, and as the color-forming substance, various dyes (color-forming dyes) are well known and used for general thermosensitive recording paper. There is no particular limitation as long as it is a thing.

Specific examples of the above color-forming dye include, for example, (1) 3,3-bis (p-dimethylaminophenyl) -6-dimethylaminophthalide, 3- (p-dimethylaminophenyl) -3- (2-phenyl-3-indolyl) phthalide, 3- (p-dimethylaminophenyl)
-3- (1,2-Dimethyl-3-indolyl) phthalide, 3,3-bis (9-ethyl-3-carbazolyl)-
Triarylmethane compounds such as 5-dimethylaminophthalide, 3,3-bis (2-phenyl-3-indolyl) -5-dimethylaminophthalide, tris (4-dimethylaminophenyl) methane; (2) 4 , 4-bis (dimethylamino) benzhydrin benzyl ether,
Diphenylmethane compounds such as N-2,4,5-trichlorophenylleuco auramine; (3) rhodamine-
β-anilinolactam, 3- (N-methyl-N-cyclohexylamino) -6-methyl-7-anilinofluoran, 3- (N-cyclohexylamino) -6-chlorofluoran, 3-diethylaminofluoran 3-diethylamino-7-octylaminofluoran, 3-diethylamino-7- (2-chloroanilino) fluoran, 3
-Diethylamino-6-methyl-7-anilinofluoran, 3-diethylamino-6-methyl-7- (2,4-
Dimethylanilino) fluoran, 3-diethylamino-
7-dibenzylaminofluoran, 3-diethylamino-6-chloro-7- (β-ethoxyethylamino) fluoran, 3-diethylamino-6-chloro-7- (γ-
Chloropropylamino) fluoran, 2-diethylamino-7- (3-trifluoromethylanilino) fluoran, 3- (N-ethyl-N-isoamylamino) -6-
Methyl-7-anilinofluoran, 3- (N-ethyl-
N-ethoxyethylamino) -6-methyl-7-anilinofluoran, 3-tetrahydropyrrolyl-6-methyl-7-anilinofluoran, 3- (N-ethyl-N-tetrahydrofurfurylamino)- 6-methyl-7-anilinofluoran, 3- (N-ethyl-N-tolylamino) -7- (N-methylanilino) fluoran, 3-
(N-ethyl-N-tolylamino) -7-methylfluoran, 3-dibutylamino-6-methyl-7-anilinofluoran, 3-dibutylamino-7- (2-chloroanilino) fluoran, 3-dipentylamino -6-methyl-7-anilinofluoran, 3-piperidino-6-methyl-7-anilinofluoran, 3- (4-anilino)
Xanthene compounds such as anilino-6-methyl-7-chlorofluorane; (4) thiazine compounds such as benzoyl leucomethylene blue and p-nitrobenzoyl leucomethylene blue; (5) 3-methylspirodinaphthopyran and 3-ethyl Spiro compounds such as spirodinaphthopyran, 3-benzylspirodinaphthopyran, 3-methylnaphtho- (3-methoxybenzo) spiropyran;
(6) Other 3,5 ', 6-tris (dimethylamino)
-Spiro [9H-fluorene-9,1 '(3'H) -isobenzofuran] -3'-one, 1,1-bis [2-
(4-dimethylaminophenyl) -2- (4-methoxyphenyl) ethenyl] -4,5,6,7-tetrachloro (3H) isobenzofuran-3-one, 2- (3-methoxy-4-dode (Siloxystyryl) quinoline and the like, and these color-forming dyes may be used in combination of several kinds.

The color-forming dye may be, if necessary, a ferric stearate, a ferric myristate, a ferric behenate, a ferric laurate, a ferral pelargonate, or oleic acid. It may be used in combination with a thermosensitive coloring agent obtained by using a ferric salt of a fatty acid such as a ferric salt and a chelating agent in combination.

Further, the compound represented by the general formula (I) used in the present invention itself has an effect as a color developer as described above, so that it is not necessary to use another color developer. However, if it is necessary to further increase the color sensitivity, a well-known developer such as a phenol type, a carboxylic acid type or a metal salt type can be used in combination. Also, by using these other developers in combination, the amount of the compound represented by the general formula (I) according to the present invention can be reduced.

Examples of the other color developing agents include, for example, p-octylphenol, p-tert-butylphenol, p-phenylphenol, p-hydroxyacetophenone, α
-Naphthol, β-naphthol, p-tert-octylcatechol, 2,2′-dihydroxybiphenyl, bisphenol-A, 1,1-bis (p-hydroxyphenyl)
Butane, 2,2-bis (4-hydroxyphenyl) heptane, 2,2-bis- (3-methyl-4-hydroxyphenyl) propane, 2,2-bis (3,5-dimethyl-
4-hydroxyphenyl) propane, 2,2-bis (3,5-dichloro-4-hydroxyphenyl) propane, bis (4-hydroxyphenyl) sulfone, bis (3-allyl-4-hydroxyphenyl) sulfone, bis ( 3,4-dihydroxyphenyl) sulfone, 2,
4'-dihydroxyphenylsulfone, 1,1-bis (4-hydroxyphenyl) cyclohexane, bis (4
-Hydroxyphenyl) ether, bis [2- (4-hydroxyphenylthio) ethoxy] methane, 4- (4-
Isopropoxybenzenesulfonyl) phenol, 4-
Dimethyl hydroxyphthalate, butyl bis (4-hydroxyphenyl) acetate, benzyl p-hydroxybenzoate, 3,5-ditert-butylsalicylic acid, 2,4-dihydroxybenzanilide, 2,4-dihydroxy-2′-
Methoxybenzanilide, 2,4-dihydroxy-
2 ', 4'-dimethylbenzanilide, 2,4-dihydroxy-2'-methoxy-5'-methylbenzanilide, bis (4- (2,4-dihydroxyphenylcarbonylamino) -3-methoxyphenyl) methane and the like Organic carboxylic acids such as phenols, resorcinols, and benzoic acid, and metal salts such as zinc salicylate. Particularly, it is preferable to use a phenol-based developer.

Various sensitizers can be used in combination to enhance the color sensitivity of the heat-sensitive recording material of the present invention. Examples thereof include zinc acetate, zinc octylate, zinc laurate, zinc stearate, and zinc oleate. Metal salts of organic acids such as zinc behenate, zinc benzoate, zinc salt of salicylic acid dodecyl ester, calcium stearate, magnesium stearate, aluminum stearate; stearamide, stearyl methylolamide, stearoyl urea, acetanilide, acetotoluidide, benzoic acid Acid stearylamide, ethylenebisstearic acid amide,
Amide compounds such as hexamethylenebisoctylamide, acetoacetic anilide, o-chloroacetoacetic anilide, acetoacetic toluidide, acetoacetic xylide, benzoylacetic anilide; 1,2-bis (3,4-dimethylphenyl) ethane, m- Terphenyl, 1,2-diphenoxyethane, 1,2-bis (3-methylphenoxy)
Ethane, p-benzylbiphenyl, p-benzyloxybiphenyl, diphenyl carbonate, bis (4-methylphenyl) carbonate, dibenzyl oxalate, bis (4-methylbenzyl) oxalate, bis (4-chlorobenzyl) oxalate, 1 Phenyl-hydroxy-2-naphthalenecarboxylate, anilide 3-hydroxy-2-naphthalenecarboxylate, benzyl 1-hydroxy-2-naphthalenecarboxylate, phenyl 3-hydroxy-2-naphthalenecarboxylate, methylenedibenzoate, 1,4 -Bis (2-vinyloxyethoxy) benzene, 2-benzyloxynaphthalene, benzyl 4-benzyloxybenzoate, methyl 4-nitrobenzoate, dimethyl phthalate, dibenzyl terephthalate, dibenzoylmethane, 4-methylphen Xy-p-biphenyl, diphenylsulfone, 1,2-diphenylethane-1,2-dione, benzenesulfonic acid anilide, p-toluenesulfonic acid anilide, and the like can be used. 0.1 to 10 parts by weight of the dye
Parts by weight are used.

In the heat-sensitive recording material of the present invention, if a particularly high storage stability is required, a known storage stabilizer can be used in combination, if necessary.

As the storage stabilizer, for example,
1,3-tris (2-methyl-4-hydroxy-5-tert-butylphenyl) butane, 1,1,3-tris (2-
Methyl-4-hydroxy-5-cyclohexylphenyl) butane, 4,4'-butylidenebis (2-tert-butyl-5-methylphenol), 4,4'-thiobis (2
-Tert-butyl-5-methylphenol), 2,2'-thiobis (6-tert-butyl-4-methylphenol),
2,2'-methylenebis (6-tert-butyl-4-methylphenol), tris (2,6-dimethyl-4-tert-butyl-3-hydroxybenzyl) isocyanurate, tris (3,5-ditert-butyl) Butyl-4-hydroxybenzyl) isocyanurate, tris (2- (3- (3,5-
Di-tert-butyl-4-hydroxyphenyl) propionyloxy) ethyl) isocyanurate, 1,3,5-tris (3,5-dimethyl-4-hydroxybenzyl)-
Hindered phenol compounds such as 2,4,6-trimethylbenzene, 4-benzyloxy-4 ′-(2-methylglycidyloxy) diphenylsulfone, sodium-2,2′-methylenebis (4,6-ditertbutyl) Phenyl) phosphate. These storage stabilizers are usually used in an amount of 0.1 to 10 parts by weight based on 1 part by weight of the chromogenic dye.
Parts by weight are used.

Although the heat-sensitive recording material of the present invention has excellent storage stability, an overcoat layer may be provided for the purpose of imparting higher storage stability, and an undercoat layer may be provided for improving color development sensitivity. It may be provided. As the overcoat layer, a conventionally known resin component such as polyvinyl alcohol may be used, any known coating method may be used, and the thickness of the coat layer is not limited at all, and may be appropriately adjusted to a desired performance. Selected. Further, as the undercoat layer, an inorganic pigment and / or
Or a layer mainly containing an organic pigment and an adhesive, a layer mainly containing a granular and / or fibrous inorganic and / or organic hollow material and an adhesive, and a foamable filler and an adhesive mainly. By using a material having excellent heat insulating properties such as a foam layer formed by a coating solution obtained by mechanically foaming an aqueous solution containing a water-soluble polymer compound or a water-dispersible polymer compound, Color development by energy becomes possible. Also in the undercoat layer, the coating method and the thickness of the coat layer are not particularly limited, and are appropriately selected according to desired performance.

When the heat-sensitive recording material of the present invention is required to provide long-term light fastness, it is preferable to add an ultraviolet absorber to the overcoat layer or the heat-sensitive recording layer. Examples of the ultraviolet absorber include 2,4-dihydroxybenzophenone, 2-hydroxy-4-methoxybenzophenone, 2-hydroxy-4-octoxybenzophenone, and 5,5′-methylenebis (2-hydroxy-4-methoxybenzophenone). 2-hydroxybenzophenones; 2- (2-hydroxy-5-methylphenyl) benzotriazole, 2- (2-hydroxy-5-tert-octylphenyl) benzotriazole, 2
-(2-hydroxy-3,5-ditert-butylphenyl)
-5-chlorobenzotriazole, 2- (2-hydroxy-3-tert-butyl-5-methylphenyl) -5-chlorobenzotriazole, 2- (2-hydroxy-3,5
-Dicumylphenyl) benzotriazole, 2,2'-
2- (2-hydroxyphenyl) such as polyethylene glycol ester of methylenebis (4-tert-octyl-6-benzotriazolyl) phenol and 2- (2-hydroxy-3-tert-butyl-5-carboxyphenyl) benzotriazole ) Benzotriazoles; phenyl salicylate, resorcinol monobenzoate, 2,4-
Benzoates such as di-tert-butylphenyl-3,5-di-tert-butyl-4-hydroxybenzoate, hexadecyl-3,5-di-tert-butyl-4-hydroxybenzoate; 2-ethyl-2'-ethoxyoxani Lido, 2-
Substituted oxanilides such as ethoxy-4′-dodecyloxanilide; ethyl-α-cyano-β, β-diphenylacrylate, methyl-2-cyano-3-methyl-3-
Cyanoacrylates such as (p-methoxyphenyl) acrylate; 2- (2-hydroxy-4-octoxyphenyl) -4,6-bis (2,4-di-tert-butylphenyl) -s-triazine; (2-hydroxy-4-
(Methoxyphenyl) -4,6-diphenyl-s-triazine, 2- (2-hydroxy-4-propoxy-5-methylphenyl) -4,6-bis (2,4-di-tert-butylphenyl) -s- And triaryltriazines such as triazine.

The heat-sensitive recording material of the present invention can be obtained, for example, as follows. First, the general formula (I)
A dispersion using the compound represented by, or separately prepared and mixed with a dispersion of the compound and a dispersion of other components such as a color-forming dye, or a dispersion of these together, Alternatively, these are mixed and melted to form a dispersion. This dispersion is usually atomized by a grinding machine such as a ball mill, an attriser, a sand grinder or an appropriate emulsifying device, and various additional materials are added according to the purpose to obtain a coating liquid using water or an organic solvent as a medium. .

Here, the above-mentioned coating liquid usually contains polyvinyl alcohol, hydroxyethyl cellulose, methyl cellulose, polyvinyl pyrrolidone, polyacrylamide polymer, starch, styrene-maleic anhydride copolymer, vinyl acetate-maleic anhydride copolymer. Binder, binder such as styrene-butadiene copolymer or modified products thereof, kaolin, silica, diatomaceous earth, talc, titanium dioxide, calcium carbonate, magnesium silicate, magnesium carbonate,
Fillers such as aluminum hydroxide and melamine are compounded, but metal soaps, amides, waxes, light stabilizers, waterproofing agents, dispersants, defoamers, etc. are used as required. be able to.

The intended heat-sensitive recording material of the present invention can be obtained by applying the coating solution obtained as described above to paper or various films.

The heat-sensitive recording material of the present invention is used as various heat-sensitive recording materials, for example, facsimile paper, printer paper, labels, price tags, tickets and the like.

[0054]

The present invention will be described in more detail with reference to the following examples. However, the present invention is not limited at all by the following examples. In the following examples, “%” means “% by weight” unless otherwise specified.

Example 1 3- (N, N-dipentylamino) -6-methyl-7-
20 g of anilinofluorane and 100 g of a 10% aqueous solution of polyvinyl alcohol were sufficiently ground with a ball mill to obtain dispersion A.

20 g of the sample compound (described in Table 1 below) was sufficiently ground in a ball mill together with 100 g of a 10% aqueous solution of polyvinyl alcohol to obtain a dispersion B.

20 g of o-chloroacetoacetic anilide are added to 1
100 g of a 0% aqueous polyvinyl alcohol solution was sufficiently ground with a ball mill to obtain a dispersion C.

As a preservative, tris (2,5-dimethyl-
10 g of 4-tert-butyl-3-hydroxybenzyl) isocyanurate in 10% aqueous solution of polyvinyl alcohol 10
The mixture was thoroughly ground in a ball mill together with 0 g to obtain a dispersion D.

The above dispersions A, B, C and D were mixed at 1: 2:
The mixture was mixed at a weight ratio of 2: 1. 50 g of calcium carbonate was added to 200 g of the mixture, and the mixture was sufficiently dispersed to form a coating solution.
This coating solution was applied on a 50 g / m ² base paper at a thickness of 32 μm and dried to obtain a thermosensitive recording material.

After the obtained heat-sensitive recording material was treated at 80 ° C. for 48 hours, a recording image (printed portion) printed with a pulse width of 0.8 msec using a heat-sensitive printing apparatus (TH-PMD: manufactured by Okura Electric Co., Ltd.) was developed. Density and background density (initial density)
Was measured using a Macbeth densitometer (model RD-933, manufactured by Macbeth).

The color-developed thermosensitive recording material was stored under drying conditions of 60 ° C. for 24 hours, the density of the background and the printed area was measured, and the heat-resistant storage stability was evaluated.

The color-developed heat-sensitive recording material was placed in a carbon arc fade meter, and after irradiating for 6 hours, the density of the printed portion was measured to evaluate the light-resistant storage stability. In addition, the density of the background was measured using a yellow filter.

Further, the density of the printed portion and the background after the vinyl chloride resin film plasticized with dioctyl phthalate was adhered to this colored heat-sensitive recording material at room temperature for 24 hours, and the oil resistance was evaluated.

The results are shown in Table 1 below.

[0065]

[Table 1]

Example 2 20 g of 3- (N-ethyl-N-isoamylamino) -6-methyl-7-anilinofluoran and 100 g of a 10% aqueous solution of polyvinyl alcohol were sufficiently ground by a ball mill to prepare dispersion A. Obtained.

20 g of sample compound (described in the following [Table 2])
Then, 100 g of a 10% aqueous polyvinyl alcohol solution was sufficiently ground with a ball mill to obtain a dispersion B.

20 g of 2-benzyloxynaphthalene and 100 g of a 10% aqueous solution of polyvinyl alcohol were sufficiently ground with a ball mill to obtain a dispersion C.

20 g of 1,1,3-tris (2-methyl-4-hydroxy-5-tert-butylphenyl) butane
This was thoroughly ground in a ball mill together with 100 g of a 0% aqueous polyvinyl alcohol solution to obtain a dispersion D.

As an ultraviolet absorber, methylene bis (2-hydroxy-3- (benzotriazol-2-yl) -5
-Tert-octylphenyl) 10 g, zinc stearate 1
0 g, 1 g of dimethylol urea and 1 g of calcium carbonate were sufficiently ground in a ball mill together with 100 g of a 10% aqueous solution of polyvinyl alcohol to obtain a dispersion E.

The above dispersions A, B, C and D are mixed at a weight ratio of 1: 2: 2: 1 and sufficiently dispersed to form a coating liquid. The coating liquid is coated on a 50 g / m ² base paper. It was applied at a thickness of 32 μm and dried to obtain a heat-sensitive recording material.

The dispersion E was added to the obtained heat-sensitive recording material by 50%.
g / m ² on the color-forming layer (thermosensitive recording layer)
A thermal recording material having a protective layer (overcoat layer) was obtained.

Using the obtained heat-sensitive recording material, the same test as in Example 1 was performed. The results are shown in Table 2 below.

[0074]

[Table 2]

As is apparent from the above results, the compound represented by the general formula (I) (compound having a structure in which hydroxyphenyl and triazine are linked by a specific bonding species)
By using as a color developer, it can be seen that a heat-sensitive recording material having good initial color density, little decoloration of a color-developed portion by a plasticizer or the like, little discoloration by light, and excellent storage stability can be obtained. (Examples 1-1 to 1-4, 2-1 to 2-
3).

[0076]

The heat-sensitive recording material of the present invention has excellent storage stability such as heat resistance, light resistance and oil resistance.

 ────────────────────────────────────────────────── ─── Continued on the front page (72) Inventor Koichi Shino 5-2-13 Shirahata, Urawa-shi, Saitama Asahi Denka Kogyo Co., Ltd.

Claims (2)

[Claims] 1. A heat-sensitive recording material characterized in that the heat-sensitive recording layer contains at least one compound represented by the following general formula (I). Embedded image 2. The heat-sensitive recording material according to claim 1, wherein A and B in the general formula (I) are a hydroxyphenyl group, and Z, Z ¹ and Z ² are an oxygen atom or a sulfur atom.