JP3217496B2 - Thermal recording material - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a heat-sensitive recording material,
In particular, the present invention relates to a heat-sensitive recording material having excellent heat responsiveness and storage stability of a background portion and an image portion.

[0002]

2. Description of the Related Art A thermosensitive recording material generally comprises a support provided with a thermosensitive recording layer mainly composed of an electron-donating, usually colorless or pale-colored dye precursor and an electron-accepting developer. By heating with a thermal head, a hot pen, a laser beam or the like, the dye precursor and the developer react instantaneously to obtain a recorded image.
It is disclosed in, for example, Japanese Patent Publication No. 14039. Such a heat-sensitive recording material has advantages such that recording can be obtained with a relatively simple device, maintenance is easy, and no noise is generated.
It is used in a wide range of fields such as measurement recorders, facsimile machines, printers, computer terminals, labels, and vending machines for tickets. Conventional heat-sensitive recording materials that use an electron-donating colorless dye precursor and an electron-accepting substance have properties such as high color density, but the recorded image area comes in contact with plastics such as polyvinyl chloride. It has the disadvantage that the storage properties of the recorded image are poor, such as discoloration due to penetration of plasticizers and additives contained in plastics, and discoloration upon contact with chemicals contained in foods and cosmetics. Or, there is a drawback that the writing marks will be discolored when writing with a writing instrument on the background, and at present it is subject to certain restrictions in its use, and its improvement has been strongly desired. .

As a heat-sensitive recording material which reacts by heating two components to obtain a recorded image having good storability, for example, JP-A-58-54085 and JP-A-58-10495.
Nos. 9, 59-11587 and 59-115888
No. 4,521,793 disclose a heat-sensitive recording material comprising an imino compound and an aromatic isocyanate compound.

[0004] Thermosensitive recording materials comprising these imino compounds and aromatic isocyanate compounds have excellent storage stability of recorded images, but have poor sensitivity (thermal response). In order to improve the sensitivity of this heat-sensitive recording material, Japanese Patent Application Laid-Open No. 61-110586 discloses an aromatic isocyanate compound, an imino compound, a specific fluoran dye, an alkylcarbonylaminophenol or an alkylaminocarbonylphenol compound. Although a four-component heat-sensitive recording material has been disclosed, its sensitivity is also insufficient, and a printing device such as a high-speed facsimile or a printer in recent years could not obtain a recorded image having a sufficient density. Also, Japanese Patent Application Laid-Open
JP-A-9-135186 discloses a heat-sensitive recording material comprising an aromatic isocyanate, an imino compound, and a leuco dye and an acidic substance which forms a color by reacting with the leuco dye. Its purpose is to spread it, and it is not sufficient in sensitivity. In addition, the fogging of the background is poor, and there is a practical problem.

[0005]

SUMMARY OF THE INVENTION The present invention relates to a heat-sensitive recording material, and more particularly, to obtain a heat-sensitive recording material having excellent heat responsiveness and storage stability of a background portion and an image portion.

[0006]

Means for Solving the Problems The inventors of the present invention have conducted intensive studies to solve the above-mentioned problems, and as a result, were able to produce a desired heat-sensitive recording material. That is, the heat-sensitive recording material of the present invention comprises, on a support, an aromatic isocyanate compound, an imino compound having at least one> C = NH group, which reacts with the isocyanate compound upon heating to form a color, and a fluoran dye. A heat-sensitive recording material provided with a heat-sensitive recording layer comprising: a heat-sensitive recording layer containing at least one of a salicylic acid derivative represented by Chemical Formula 3 or Chemical Formula 4 or a metal salt thereof. It is.

[0007]

Embedded image (In the formula, Y represents a hydrogen atom, an alkyl group or a halogen atom, and R represents an alkyl group having 4 to 18 carbon atoms.)

Embedded image (In the formula, Y represents a hydrogen atom, an alkyl group, or a halogen atom, and R represents an alkyl group having 4 to 18 carbon atoms.)

Specific examples of the salicylic acid derivative represented by the general formula 1 or 2 or the metal salt thereof include, for example, the following, but the present invention is not limited thereto. .

(1) 3-n-butyloxysalicylic acid (2) 3-n-pentyloxysalicylic acid (3) 3-n-hexyloxysalicylic acid (4) 3-cyclohexyloxysalicylic acid (5) 3-n-octyloxy Salicylic acid (6) 3-n-decyloxysalicylic acid (7) 3-n-dodecyloxysalicylic acid (8) 3-n-tetradecyloxysalicylic acid (9) 3-n-hexadecyloxysalicylic acid (10) 3-n- Octadecyloxysalicylic acid (11) 4-n-butyloxysalicylic acid (12) 4-n-pentyloxysalicylic acid (13) 4-n-hexyloxysalicylic acid (14) 4-cyclohexyloxysalicylic acid (15) 4-n-octyloxy Salicylic acid (16) 4-n-decyloxysalicylic acid (17) 4-n -Dodecyloxysalicylic acid (18) 4-n-tetradecyloxysalicylic acid (19) 4-n-hexadecyloxysalicylic acid (20) 4-n-octadecyloxysalicylic acid

(21) 5-n-butyloxysalicylic acid (22) 5-n-pentyloxysalicylic acid (23) 5-n-hexyloxysalicylic acid (24) 5-cyclohexyloxysalicylic acid (25) 5-n-octyloxy Salicylic acid (26) 5-n-decyloxysalicylic acid (27) 5-n-dodecyloxysalicylic acid (28) 5-n-tetradecyloxysalicylic acid (29) 5-n-hexadecyloxysalicylic acid (30) 5-n- Octadecyloxysalicylic acid (31) 6-n-butyloxysalicylic acid (32) 6-n-pentyloxysalicylic acid (33) 6-n-hexyloxysalicylic acid (34) 6-cyclohexyloxysalicylic acid (35) 6-n-octyloxy Salicylic acid (36) 6-n-decyloxysalicy Acid (37) 6-n- dodecyloxy salicylic acid (38) 6-n- tetradecyloxy salicylic acid (39) 6-n- hexadecyloxy salicylic acid (40) 6-n- octadecyl-oxy salicylic acid

(41) 3-n-hexylaminosalicylic acid (42) 3-n-octylaminosalicylic acid (43) 3-n-decylaminosalicylic acid (44) 3-n-octadecylaminosalicylic acid (45) 4-n- Hexylaminosalicylic acid (46) 4-n-octylaminosalicylic acid (47) 4-n-decylaminosalicylic acid (48) 4-n-dodecylaminosalicylic acid

In the metal salt of a salicylic acid derivative represented by the general formula 1 or 2 of the present invention, the metal salt is
It contains a monovalent metal salt such as sodium, potassium and lithium, but is preferably a poorly water-soluble or water-insoluble divalent, trivalent or tetravalent metal salt, more preferably a divalent metal salt. It is a trivalent metal salt.

Specific examples of divalent, trivalent, and tetravalent metal salts include zinc, cadmium, mercury, magnesium, calcium, barium, nickel, tin, gallium, chromium, and the like.
Copper, molybdenum, tungsten, zirconium, strontium, manganese, cobalt, titanium, aluminum, iron salts, but preferably zinc,
It is a salt of calcium, barium, nickel, manganese, cobalt and aluminum. Particularly, a zinc salt is preferable.

The amount of the salicylic acid derivative represented by Chemical Formula 3 or Chemical Formula 4 or the metal salt thereof is preferably 50 to 250% by weight based on the fluoran dye. If the amount is less than 50% by weight, the fluoran dye cannot be completely colored, so that the sensitivity is insufficiently improved. If the amount is more than 250% by weight, no remarkable improvement effect on the sensitivity is observed, which is economically disadvantageous. .

The aromatic isocyanate compound used in the present invention is a colorless or pale-colored aromatic isocyanate compound or heterocyclic isocyanate compound which is a solid at room temperature. For example, one or more of the following compounds are used. 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-diisocyanate, 1-methoxybenzene-2,4-diisocyanate, 1-methoxybenzene-2,5-diisocyanate, 1-ethoxybenzene-2,4- Diisocyanate, 2,5-dimethoxybenzene-1,4-diisocyanate, 2,5-diethoxybenzene-1,4-diisocyanate, 2,5-dibutoxybenzene-1,4-diisocyanate, azobenzene -4,4'-diisoanatate, diphenylether-4,4'-diisocyanate, naphthalene-1,4-diisocyanate, naphthalene-1,5-diisocyanate, naphthalene-2,6-
Diisocyanate, naphthalene-2,7-diisocyanate, 3,3'-dimethyl-biphenyl-4,4'-diisocyanate, 3,3'-dimethoxybiphenyl-
4,4'-diisocyanate, diphenylmethane-4,
4'-diisocyanate, diphenyldimethylmethane-
4,4'-diisocyanate, benzophenone-3,
3'-diisocyanate, fluorene-2,7-diisocyanate, anthraquinone-2,6-diisocyanate, 9-ethylcarbazole-3,6-diisocyanate, pyrene-3,8-diisocyanate Nart, naphthalene-
1,3,7-triisocyanate, biphenyl-2,
4,4'-triisocyanate, 4,4 ', 4 "-triisocyanate-2,5-dimethoxytriphenylamine, p-dimethylaminophenyl isocyanate, tris (4-phenylisocyanate) thiophosphate and the like. is there.

These isocyanate compounds may be used as so-called block isocyanates, which are adducts with phenols, lactams, oximes, etc., if necessary, and diisocyanate dimers. For example, it may be used in the form of isocyanurate which is a dimer and trimer of 1-methylbenzene-2,4-diisocyanate, or used as a polyisocyanate adducted with various polyols and the like. It is also possible.

The imino compound used in the present invention is a compound represented by the formula (5), which is a colorless or pale-colored solid at room temperature.

[0018]

Embedded image (Formula 3) where φ represents an aromatic compound residue capable of forming a conjugated system with adjacent CＣN.

A specific example will be described below. Two or more imino compounds can be used in combination depending on the purpose. 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-methoxy-isoindoline-
1-one, 3-imino-4,5,7-trichloro-6-
Methylmercapto-isoindoline-1-one, 3-imino-6-nitroisoindoline-1-one, 3-imino-isoindoline-1-spiro-dioxolan, 1,
1-dimethoxy-3-imino-isoindoline, 1,1
-Diethoxy-3-imino-4,5,6,7-tetrachloroisoindoline, 1-ethoxy-3-imino-isoindoline, 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, 7-amino-2,3-dimethyl-5-oxopyrrolo [3,4b] pyrazine, 7-
Amino-2,3-diphenyl-5-oxopyrrolo [3,
4b] pyrazine, 1-iminonaphthalimide, 1-iminodiphenimide, 1-phenylimino-3-iminoisoindoline, 1- (3'-chlorophenylimino) -3-iminoisoindoline, 1- (2 ', 5 '-
Dichlorophenylimino) -3-iminoisoindoline, 1- (2 ', 4', 5'-trichlorophenylimino-3-iminoisoindoline,

1- (2'-cyano-4'-nitrophenylimino) -3-iminoisoindoline, 1- (2'-
Chloro-5'-cyanophenylimino) -3-iminoisoindoline, 1- (2 ', 6'-dichloro-4'-nitrophenylimino) -3-iminoisoindoline, 1
-(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- 3'-N, N-
Dimethylamino-4'-methoxyphenylimino) -3
-Iminoisoindoline, 1- (2'-methoxy-5 '
-N-phenylcarbamoylphenylimino) -3-iminoisoindoline, 1- (2'-chloro-5'-trifluoromethylphenylimino) -3-iminoisoindoline, 1- (5 ', 6'-dichlorobenzo) Thiazolyl-2'-imino) -3-iminoisoindoline, 1-
(6'-methylbenzothiazolyl-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-
(Viridyl-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-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- (benzimidazolyl-2'-imino) -3-imino-4,7-dithiatetrahydroisoindoline, 1- (4 ', 5'-dicyanoimidazolyl-2'-imino) -3 -Imino-5, 6
-Dimethyl-4,7-pyradiisoindoline, 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-N- (3'-chloro-4'-methylphenyl) -carbamoylmethylene] -3-iminoisoindoline, 1- (cyano-p-nitrophenylmethylene)-
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-[(1'-phenyl-
3'-methyl-5-oxo) -pyrazolidene-4 ']-
3-iminoisoindoline,

1-[(Cyanobenzimidazolyl-
2 ')-methylene] -3-imino-4,7-dithiatetrahydroisoindoline, 1-[(cyanobenzimidazolyl-2') methylene-3-imino-5,6-dimethyl-4,7-pyradine Isoindoline, 1-[(1'-methyl-3'-n-butyl) -barbituric acid-5 ']-3
-Iminoisoindoline, 3-imino-1-sulfobenzoic imide, 3-imino-1-sulfo-6-chlorobenzoic imide, 3-imino-1-sulfo-5,6-dichlorobenzoic imide, 3- Imino-1-sulfo-4,5
6,7-tetrachlorobenzoic acid imide, 3-imino-1
-Sulfo-4,5,6,7-tetrabromobenzoic imide, 3-imino-1-sulfo-4,5,6,7-tetrafluorobenzoic imide, 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-promonaphthoic acid imide, 3-imino-2-methyl-4,5,6,7-tetrachloroisoindoline-1-one and the like.

The fluoran dye is preferably a black-colored fluoran dye from the viewpoint of the color tone of the aromatic isocyanate compound and at least one imino compound having at least one> C = NH group and the light resistance of the fluoran dye itself. . Examples of such fluoran dyes include 3-diethylamino-6-methyl-7-anilinofluoran,
-Dibutylamino-6-methyl-7-anilinofluoran, 3-methylpropylamino-6-methyl-7-anilinofluoran, 3-diethylamino-6-methyl-7
-(2 ', 3'-dimethylanilino) fluoran, 3-
Piperidino-6-methyl-7-anilinofluoran, 3
-Pyrrolidino-6-methyl-7-anilinofluoran,
3-diethylamino-7- (2'-chloroanilino) fluoran, 3-dibutylamino-7- (2'-chloroanilino) fluoran, 3-dibutylamino-7- (2 '
-Fluoroanilino) fluoran and the like.

The heat-sensitive recording material of the present invention may contain a heat-fusible substance in order to improve its thermal response. In this case, those having a melting point of 60 ° C to 180 ° C are preferable, and those having a melting point of 80 ° C to 140 ° C are more preferable. Specific examples of such substances include N-
Waxes such as hydroxymethylstearic acid amide, stearic acid amide, palmitic acid amide, oleic acid amide, ethylene bisstearic acid amide, ricinoleic acid amide, paraffin wax, microcrystalline wax, polyethylene wax, rice wax, carnauba wax; Naphthol derivatives such as -benzyloxynaphthalene, p-benzylbiphenyl,
Biphenyl derivatives such as 4-allyloxybiphenyl,
1,2-bis (3-methylphenoxy) ethane, 2,
Polyether compounds such as 2'-bis (4-methoxyphenoxy) diethyl ether and bis (4-methoxyphenyl) ether, diphenyl carbonate, dibenzyl oxalate,
Examples thereof include carbonic acid or oxalic acid diester derivatives such as oxalic acid di (p-methylbenzyl) ester. These sensitizers can be used alone or in combination of two or more.

Examples of the binder used for the heat-sensitive recording material include starches, hydroxyethylcellulose, methylcellulose, carboxymethylcellulose, gelatin, casein, polyvinyl alcohol, modified polyvinyl alcohol, sodium polyacrylate, acrylamide / acrylate copolymer. Acrylamide / acrylic ester / methacrylic acid terpolymer, styrene / maleic anhydride copolymer alkali salt, ethylene /
Water-soluble adhesives such as alkali salts of maleic anhydride copolymer, polyvinyl acetate, polyurethane, polyacrylate, styrene / butadiene copolymer, acrylonitrile / butadiene copolymer, methyl acrylate / butadiene copolymer, Latexes such as an ethylene / vinyl acetate copolymer are exemplified.

Examples of the pigment include diatomaceous earth, talc, kaolin, calcined kaolin, calcium carbonate, magnesium carbonate, titanium oxide, zinc oxide, silicon oxide, aluminum hydroxide, and urea-formalin resin.

In addition, higher fatty acid metal salts such as zinc stearate and calcium stearate, waxes such as paraffin, paraffin oxide, polyethylene, polyethylene oxide and caster wax, and dioctyl sulfosuccinic acid for the purpose of preventing head wear and sticking. A dispersant such as sodium, a benzophenone-based or benzotriazole-based ultraviolet absorber, a surfactant, a fluorescent dye, and the like are added as necessary.

As the support used in the present invention, paper is mainly used, but non-woven fabric, plastic film, synthetic paper, metal foil and the like, or a composite sheet combining these can be used arbitrarily. Further, in order to protect the heat-sensitive recording layer, heat-sensitive recording such as providing an overcoat layer, or providing a single layer or a plurality of undercoat layers made of pigments or resins between the heat-sensitive recording layer and the support. Various known techniques for producing materials can be used.

[0030]

Next, the present invention will be described in more detail by way of examples. All parts and percentages shown below are based on weight.

Example 1 [Preparation of heat-sensitive recording material] (A) Preparation of heat-sensitive coating solution 15 g of 1,3-diimino-4,5,6,7-tetrachloroisoindoline was added to a 1% aqueous solution of polyvinyl alcohol 6
With 0 g, it was dispersed by a Dynomill so that the average particle diameter became 2 μm. On the other hand, 4,4 ', 4 "-triisocyanato-2,5-dimethoxytriphenylamine 10
g was dispersed together with a 1% aqueous solution of polyvinyl alcohol using a Dynomill such that the average particle size became 2 μm.
Further, 10 g of 3-dibutylamino-6methyl-7-anilinofluorane was added to 40 g of a 1% aqueous solution of polyvinyl alcohol.
At the same time, they were dispersed by a Dynomill so that the average particle diameter became 2 μm. In addition, 15 g of zinc 4-n-octyloxysalicylate was dispersed together with 60 g of a 1% aqueous solution of polyvinyl alcohol by a Dynomill so as to have an average particle diameter of 2 μm. After mixing these four dispersions, 200 g of a 40% dispersion of calcium carbonate was added, 25 g of a 40% dispersion of zinc stearate, 100 g of a 20% dispersion of 2-benzyloxynaphthalene, 10 g of 10% polyvinyl alcohol 160 g of an aqueous solution and 65 g of water were added to obtain a sufficiently stirred coating solution.

(B) Preparation of Thermal Coated Paper A coating liquid having the following composition was applied to base paper having a basis weight of 40 g / m ^{2 so} as to have a solid content of 9 g / m ² and dried. Created paper. Calcined kaolin 100 parts 50% styrene butadiene latex aqueous dispersion 24 parts Water 200 parts

(C) Preparation of heat-sensitive recording material The heat-sensitive coating solution prepared in (A) is smeared onto the heat-sensitive coating paper surface prepared in (B) so as to have a solid content of 4 g / m ² . After drying, a heat-sensitive recording material was prepared.

Example 2 A heat-sensitive recording material was prepared in the same manner as in Example 1 except that zinc 4-n-butyloxysalicylate was used in place of zinc 4-n-octyloxysalicylate.

Example 3 A heat-sensitive recording material was prepared in the same manner as in Example 1 except that zinc 4-n-octadecyloxysalicylate was used instead of zinc 4-n-octyloxysalicylate.

Reference Example 1 A heat-sensitive recording material was prepared in the same manner as in Example 1 except that zinc 4-n-octanoylsalicylate was used instead of zinc 4-n-octyloxysalicylate.

Example 4 A heat-sensitive recording material was prepared in the same manner as in Example 1, except that zinc 4-n-octadecyloxysalicylate was used instead of zinc 4-n-octyloxysalicylate.

Comparative Example 1 A heat-sensitive recording material was prepared in the same manner as in Example 1 except that zinc 4-n-octyloxysalicylate in Example 1 was changed to 2,2-bis (4-hydroxyphenyl) propane.

Comparative Example 2 A heat-sensitive recording material was prepared in the same manner as in Example 1 except that zinc 4-n-octyloxysalicylate was omitted.

[Evaluation of Coloring Characteristics] Facsimile tester TH manufactured by Okura Electric Co., Ltd.
-A print test was performed using PMD. Using a thermal head with a dot density of 8 dots / mm and a head resistance of 185Ω, printing is performed by energizing with a head voltage of 12 V, a pulse width of 0.7 and 1.0 ms, and a color density of Macbeth RD-918.
It was measured with a reflection densitometer. Table 1 shows the results.

As for the preservation characteristics of the background, a writing instrument test was conducted.

[Writing Resistance Test on Background] In the writing resistance test, after writing on the non-image area with a highlighter, the stain on the non-image area after standing at room temperature for 72 hours was visually determined. ○ indicates almost no stain, and X indicates that coloring has occurred. Table 1 shows the results.

For the storage characteristics of the image portion, a lap resistance test and a writing instrument test were performed.

[Lap resistance test of image portion] The lap resistance test was performed by covering a printed portion of each thermosensitive recording material printed with a pulse of 1.0 msec used in the evaluation of the color development characteristics with a commercially available wrap, and 2 g / cm ² from the top. And the state of decoloration of the printed portion after storage for 24 hours in an environment of 40 ° C. was visually judged.
○ indicates that the printed portion remains almost unerased, and X indicates that the printed portion is almost erased and the printed information is difficult to read.

[Writing resistance test of image portion] The writing resistance test was performed by writing with a highlighter on the printing portion of each thermosensitive recording material printed with the pulse of 1.0 msec used in the evaluation of the color development test.
The decolored state of the printed portion after standing at room temperature for 72 hours was visually judged. The results are shown in Table 1.

[0046]

[Table 1]

[0047]

As is clear from the examples, the heat-sensitive recording material of the present invention contains a compound represented by the general formula 1 in three components of an aromatic isocyanate compound, an imino compound and a fluoran dye.
Alternatively, by coating a heat-sensitive recording layer composition containing at least one of a salicylic acid derivative represented by the general formula 2 or a metal salt thereof on a support, thermal responsiveness and background stability, and storage stability of an image portion are improved. An excellent heat-sensitive recording material was obtained.

Continuation of the front page (56) References JP-A-59-135186 (JP, A) JP-A-62-95288 (JP, A) JP-A-63-95977 (JP, A) JP-A-63-95979 (JP, A) JP-A-3-293196 (JP, A) JP-A-3-15587 (JP, A) JP-A-61-110586 (JP, A) JP-A-7-110586 (JP, A) 5-92664 (JP, A) (58) Fields investigated (Int. Cl. ⁷ , DB name) B41M 5/28-5/34

Claims (2)

(57) [Claims] 1. A thermosensitive recording comprising, on a support, an aromatic isocyanate compound, an imino compound having at least one> C = NH group which develops a color by reacting with the isocyanate compound when heated, and a fluoran dye. A heat-sensitive recording material having a layer coated thereon, wherein the heat-sensitive recording layer contains at least one of a salicylic acid derivative represented by Chemical Formula 1 or a metal salt thereof. Embedded image (In the formula, Y represents a hydrogen atom, an alkyl group, or a halogen atom, and R represents an alkyl group having 4 to 18 carbon atoms.) 2. A thermosensitive recording comprising, on a support, an aromatic isocyanate compound, an imino compound having at least one> C = NH group which reacts with the isocyanate compound upon heating to form a color, and a fluoran dye. A heat-sensitive recording material having a layer provided thereon, wherein the heat-sensitive recording layer contains at least one of a salicylic acid derivative represented by Chemical Formula 2 or a metal salt thereof. Embedded image (In the formula, Y represents a hydrogen atom, an alkyl group or a halogen atom, and R represents an alkyl group having 4 to 18 carbon atoms.)