JPH07137440A - Heat-sensitive recording material - Google Patents

Abstract

PURPOSE:To improve heat responsiveness and preservation stability by a method wherein at least one of sqecified salicylic acid derivatives and its metal salts is included in heat-sensitive recording layer, which contains aromatic isocyanate compound and is applied on support for producing heat-sensitive recording material.. CONSTITUTION:In heat-sensitive recording material produced by coating heat- sensitive recording layer, which consists of aromatic isocyanate compound, imino compound having at least one >C=NH group, which develops color under heat by being reacted with the above-mentioned compound, and fluoran dye, on support, the heat-sensitive recording layer contains at least one of the salicylic acid derivatives represented by the separate general formula or its metal salt, in which X1 and X2 represent hydrogen atom, alkyl group, aralkyl group or the like, R is alkyl group, alkenyl group, aralkyl group or the like. As the above-mentioned salicylic acid derivative or its metal salt, 3-methyl oxycarbonyl amino salicylic acid, 3-n-propyl oxycarbonyl amino salicylic acid or the like is exampled.

Description

Detailed Description of the Invention

[0001]

FIELD OF THE INVENTION The present invention relates to a thermal recording material,
In particular, the present invention relates to a heat-sensitive recording material which is excellent in heat responsiveness and storage stability of a background portion and an image portion.

[0002]

2. Description of the Related Art A heat-sensitive recording material generally comprises a support and a heat-sensitive recording layer mainly composed of an electron-donating, usually colorless or light-colored dye precursor and an electron-accepting developer. By heating with a thermal head, a heating pen, a laser beam or the like, a dye precursor and a developer react instantaneously to obtain a recorded image. JP-B-43-4160 and 45-45
No. 14039 is disclosed. Such a heat-sensitive recording material has the advantages that recording can be obtained with a relatively simple device, that maintenance is easy, and that noise is not generated, and measurement recorders, facsimiles, printers, computer terminals, It is used in a wide range of fields such as labels and ticket vending machines. Conventional thermal recording materials using an electron-donating colorless dye precursor and an electron-accepting substance have characteristics such as high color density, but on the other hand, the recorded image area is in contact with plastic such as polyvinyl chloride. And then erased by permeation of plasticizers and additives contained in the plastic,
It has the drawback of poor storage characteristics of the recorded image, such as being discolored by contact with chemicals contained in foods and cosmetics, or the discoloration of the handwriting when writing with a writing instrument on the background. The present situation is that it has certain restrictions on its use, and its improvement has been strongly desired.

As a heat-sensitive recording material which reacts when two components are heated to obtain a recorded image having good storability, for example, JP-A-58-54085 and 58-10495.
No. 9, No. 59-115888, No. 59-115888
Each of the publications and U.S. Pat. No. 4,521,793 disclose a heat-sensitive recording material comprising an imino compound and an aromatic isocyanate compound.

The heat-sensitive recording materials comprising these imino compounds and aromatic isocyanate compounds have very good storability of recorded images, but have poor sensitivity (thermoresponsiveness). For the purpose of improving the sensitivity of this heat-sensitive recording material, JP-A-61-110586 discloses that an aromatic isocyanate compound, an imino compound, a specific fluorane dye, an alkylcarbonylaminophenol or an alkylaminocarbonylphenol compound. Although a heat-sensitive recording material composed of four components has been disclosed, the sensitivity is also insufficient, and a recording image having a sufficient density cannot be obtained by a printing apparatus such as a high speed facsimile and a printer in recent years. In addition, JP-A-5
Japanese Patent Application Laid-Open No. 9-135186 discloses a heat-sensitive recording material comprising an aromatic isocyanate, an imino compound, a leuco dye and an acidic substance that develops a color by reacting with the leuco dye. Although it spreads only for a long time and the color developing property is improved, the fog on the background becomes worse and there is a practical problem.

[0005]

SUMMARY OF THE INVENTION The present invention relates to a heat-sensitive recording material, and particularly to obtain a heat-sensitive recording material excellent in heat response and storage stability of the background portion and the image portion.

[0006]

As a result of intensive studies to solve the above-mentioned problems, the inventors of the present invention were able to produce the 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 develops a color upon reaction with the isocyanate compound, and a fluorane dye. A heat-sensitive recording material coated with a heat-sensitive recording layer consisting of: wherein the heat-sensitive recording layer contains at least one salicylic acid derivative represented by Chemical formula 2 or a metal salt thereof.

[0007]

[Chemical 2] (In the formula, X ₁ and X ₂ represent a hydrogen atom, an alkyl group, an aralkyl group, an aryl group, or a halogen atom, and R represents
It represents an alkyl group, an alkenyl group, an aralkyl group, or an aryl group. )

Specific examples of the salicylic acid derivative represented by the general formula 1 or the metal salt thereof according to the present invention include:
Although the following are listed, the present invention is not limited thereto.

(1) 3-Methyloxycarbonylaminosalicylic acid (2) 3-ethyloxycarbonylaminosalicylic acid (3) 3-n-propyloxycarbonylaminosalicylic acid (4) 3-isopropyloxycarbonylaminosalicylic acid (5) 3- n-Butyloxycarbonylaminosalicylic acid (6) 3-isobutyloxycarbonylaminosalicylic acid (7) 3-sec-butyloxycarbonylaminosalicylic acid (8) 3-n-pentyloxycarbonylaminosalicylic acid (9) 3-isopentyloxycarbonyl Aminosalicylic acid (10) 3-n-hexyloxycarbonylaminosalicylic acid (11) 3-n-heptyloxycarbonylaminosalicylic acid (12) 3-n-octyloxycarbonylaminosalicylic acid (13) 3 (2'-Ethylhexyl) oxycarbonylaminosalicylic acid (14) 3-n-nonyloxycarbonylaminosalicylic acid (15) 3-n-decyloxycarbonylaminosalicylic acid (16) 3-n-undecyloxycarbonylaminosalicylic acid (17) 3-n-dodecyloxycarbonylaminosalicylic acid (18) 3-n-tridecyloxycarbonylaminosalicylic acid (19) 3-n-tetradecyloxycarbonylaminosalicylic acid (20) 3-n-pentadecyloxycarbonylaminosalicylic acid (21) ) 3-n-hexadecyloxycarbonylaminosalicylic acid (22) 3-n-heptadecyloxycarbonylaminosalicylic acid (23) 3-n-octadecyloxycarbonylaminosalicylic acid (24) 3-cyclopen (25) 3-Cyclohexyloxycarbonylaminosalicylic acid (26) 3-Allyloxycarbonylaminosalicylic acid (27) 3-Benzyloxycarbonylaminosalicylic acid (28) 3-Phenyloxycarbonylaminosalicylic acid (29) 3- (4'-Methylphenyl) oxycarbonylaminosalicylic acid (30) 3- (4'-methoxyphenyl) oxycarbonylaminosalicylic acid

(31) 3- (4'-chlorophenyl) oxycarbonylaminosalicylic acid (32) 3- [2 '-(4-methoxyphenyl) oxyethyl] oxycarbonylaminosalicylic acid (33) 4-methyloxycarbonylaminosalicylic acid ( 34) 4-Ethyloxycarbonylaminosalicylic acid (35) 4-n-propyloxycarbonylaminosalicylic acid (36) 4-Isopropyloxycarbonylaminosalicylic acid (37) 4-n-butyloxycarbonylaminosalicylic acid (38) 4-isobutyloxy Carbonylaminosalicylic acid (39) 4-sec-butyloxycarbonylaminosalicylic acid (40) 4-n-pentyloxycarbonylaminosalicylic acid (41) 4-isopentyloxycarbonylaminosalicylic acid (42) ) 4-n-hexyloxycarbonylaminosalicylic acid (43) 4-n-heptyloxycarbonylaminosalicylic acid (44) 4-n-octyloxycarbonylaminosalicylic acid (45) 4- (2′-ethylhexyl) oxycarbonylaminosalicylic acid 46) 4-n-nonyloxycarbonylaminosalicylic acid (47) 4-n-decyloxycarbonylaminosalicylic acid (48) 4-n-undecyloxycarbonylaminosalicylic acid (49) 4-n-dodecyloxycarbonylaminosalicylic acid (50) ) 4-n-Tridecyloxycarbonylaminosalicylic acid (51) 4-n-tetradecyloxycarbonylaminosalicylic acid (52) 4-n-pentadecyloxycarbonylaminosalicylic acid (53) 4-n-hexadecylo Cycarbonylaminosalicylic acid (54) 4-n-heptadecyloxycarbonylaminosalicylic acid (55) 4-n-octadecyloxycarbonylaminosalicylic acid (56) 4-cyclopentyloxycarbonylaminosalicylic acid (57) 4-cyclohexyloxycarbonylaminosalicylic acid ( 58) 4-allyloxycarbonylaminosalicylic acid (59) 4-benzyloxycarbonylaminosalicylic acid (60) 4-phenyloxycarbonylaminosalicylic acid

(61) 4- (4'-methylphenyl) oxycarbonylaminosalicylic acid (62) 4- (4'-methoxyphenyl) oxycarbonylaminosalicylic acid (63) 4- (4'-chlorophenyl) oxycarbonylaminosalicylic acid (64) 4- [2 '-(4-methoxyphenyl) oxyethyl] oxycarbonylaminosalicylic acid (65) 5-methyloxycarbonylaminosalicylic acid (66) 5-ethyloxycarbonylaminosalicylic acid (67) 5-n-propyloxy Carbonylaminosalicylic acid (68) 5-isopropyloxycarbonylaminosalicylic acid (69) 5-n-butyloxycarbonylaminosalicylic acid (70) 5-isobutyloxycarbonylaminosalicylic acid (71) 5-sec-butyloxycarbonic acid Aminosalicylic acid (72) 5-n-pentyloxycarbonylaminosalicylic acid (73) 5-Isopentyloxycarbonylaminosalicylic acid (74) 5-n-hexyloxycarbonylaminosalicylic acid (75) 5-n-heptyloxycarbonylaminosalicylic acid ( 76) 5-n-octyloxycarbonylaminosalicylic acid (77) 5- (2′-ethylhexyl) oxycarbonylaminosalicylic acid (78) 5-n-nonyloxycarbonylaminosalicylic acid (79) 5-n-decyloxycarbonylaminosalicylic acid (80) 5-n-undecyloxycarbonylaminosalicylic acid (81) 5-n-dodecyloxycarbonylaminosalicylic acid (82) 5-n-tridecyloxycarbonylaminosalicylic acid (83) 5-n Tetradecyloxycarbonylaminosalicylic acid (84) 5-n-pentadecyloxycarbonylaminosalicylic acid (85) 5-n-hexadecyloxycarbonylaminosalicylic acid (86) 5-n-heptadecyloxycarbonylaminosalicylic acid (87) 5- n-octadecyloxycarbonylaminosalicylic acid (88) 5-cyclopentyloxycarbonylaminosalicylic acid (89) 5-cyclohexyloxycarbonylaminosalicylic acid (90) 5-allyloxycarbonylaminosalicylic acid

(91) 5-benzyloxycarbonylaminosalicylic acid (92) 5-phenyloxycarbonylaminosalicylic acid (93) 5- (4'-methylphenyl) oxycarbonylaminosalicylic acid (94) 5- (4'-methoxyphenyl) ) Oxycarbonylaminosalicylic acid (95) 5- (4'-chlorophenyl) oxycarbonylaminosalicylic acid (96) 5- [2 '-(4-methoxyphenyl) oxyethyl] oxycarbonylaminosalicylic acid (97) 6-methyloxycarbonylamino Salicylic acid (98) 6-ethyloxycarbonylaminosalicylic acid (99) 6-n-propyloxycarbonylaminosalicylic acid (100) 6-isopropyloxycarbonylaminosalicylic acid (101) 6-n-butyloxycarboni Aminosalicylic acid (102) 6-isobutyloxycarbonylaminosalicylic acid (103) 6-sec-Butyloxycarbonylaminosalicylic acid (104) 6-n-pentyloxycarbonylaminosalicylic acid (105) 6-isopentyloxycarbonylaminosalicylic acid (106) 6-n-hexyloxycarbonylaminosalicylic acid (107) 6-n-heptyloxycarbonylaminosalicylic acid (108) 6-n-octyloxycarbonylaminosalicylic acid (109) 6- (2'-ethylhexyl) oxycarbonylaminosalicylic acid (110) ) 6-n-nonyloxycarbonylaminosalicylic acid (111) 6-n-decyloxycarbonylaminosalicylic acid (112) 6-n-undecyloxycarbonylaminosalicylic acid (113) 6-n-dodecyloxycarbonylaminosalicylic acid (114) 6-n-tridecyloxycarbonylaminosalicylic acid (115) 6-n-tetradecyloxycarbonylaminosalicylic acid (116) 6-n-pentadecyloxycarbonylamino Salicylic acid (117) 6-n-hexadecyloxycarbonylaminosalicylic acid (118) 6-n-heptadecyloxycarbonylaminosalicylic acid (119) 6-n-octadecyloxycarbonylaminosalicylic acid (120) 6-cyclopentyloxycarbonylaminosalicylic acid

(121) 6-Cyclohexyloxycarbonylaminosalicylic acid (122) 6-allyloxycarbonylaminosalicylic acid (123) 6-benzyloxycarbonylaminosalicylic acid (124) 6-phenyloxycarbonylaminosalicylic acid (125) 6- (4 '-Methylphenyl) oxycarbonylaminosalicylic acid (126) 6- (4'-methoxyphenyl) oxycarbonylaminosalicylic acid (127) 6- (4'-chlorophenyl) oxycarbonylaminosalicylic acid (128) 6- [2'-( 4-Methoxyphenyl) oxyethyl] oxycarbonylaminosalicylic acid

In the metal salt of the salicylic acid derivative represented by the general formula 1 according to the present invention, the metal salt contains a monovalent metal salt such as sodium, potassium or lithium, but is preferably sparingly soluble in water. Alternatively, it is a water-insoluble divalent, trivalent or tetravalent metal salt, more preferably a divalent or trivalent metal salt.

Specific examples of the divalent, trivalent or tetravalent metal salt include zinc, cadmium, mercury, magnesium, calcium, barium, nickel, tin, gallium, chromium, copper, molybdenum, tungsten, zirconium, strontium and manganese. , Cobalt, titanium, aluminum and iron salts can be mentioned, but zinc, calcium, barium, nickel, manganese, cobalt and aluminum salts are preferable. A zinc salt is particularly preferable. The metal salt of salicylic acid represented by the general formula 1 may form a solvate such as a hydrate depending on the production conditions, and the solvate is also suitable as the electron-accepting compound of the present invention.

The salicylic acid derivative represented by the general formula 1 or the metal salt thereof according to the present invention can be prepared by a known method {for example, J.
Pharm. Sci. , 52, 927 (1963), B
all. de. Socie. Chim. France,
1189 (1955). That is, for example, the aminosalicylic acid derivative can be suitably synthesized by reacting a chloroformate compound in an approximately equivalent amount.

The salicylic acid derivative represented by the general formula 1 or its metal salt is added in an amount of 5 relative to the fluoran dye.
0 to 250% by weight is preferred. If it is less than 50% by weight, the fluoran dye cannot completely develop color, so that the sensitivity is not sufficiently improved. If it is more than 250% by weight, the sensitivity is not significantly improved, which is economically disadvantageous. .

The aromatic isocyanate compound used in the present invention is a colorless or light-colored aromatic isocyanate compound or heterocyclic isocyanate compound which is solid at room temperature, and for example, one or more of the following may be used.

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-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
-Diisoanato, azobenzene-4,4'-diisoanato, 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-ethylcarbazol-3,6-diisocyanate, pyrene-3,8-diisocyanate Nato, naphthalene
13,7-triisocyanate, biphenyl-2,4
4'-triisocyanate, 4,4'4 "-triisocyanate-2,5-dimethoxytriphenylamine, p
-Dimethylaminophenyl isocyanate, tris (4
-Phenylisocyanate) thiophosphate and the like.

If desired, these isocyanate compounds may be used in the form of so-called block isocyanates, which are addition compounds with phenols, lactams, oximes, etc., and dimers of diisocyanate. 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. It is also possible.

The imino compound used in the present invention is a compound represented by Chemical formula 3, which is a colorless or light-colored compound which is solid at room temperature.

[0022]

[Chemical 3] However, in Chemical formula 3, φ represents an aromatic compound residue capable of forming a conjugated system with the adjacent C = N.

A specific example will be shown below. It is also possible to use two or more types of imino compounds in combination depending on the purpose. 3-iminoisoindoline-1-one, 3-imino-4,5,5
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-dioxolane, 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 [3,3
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-
(Vyridyl-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-4,5,5
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-pyrazy Isoindoline, 1-[(1'-methyl-3'-n-butyl) -barbituric acid-5 ']-3
-Iminoisoindoline, 3-imino-1-sulfobenzoic acid imide, 3-imino-1-sulfo-6-chlorobenzoic acid imide, 3-imino-1-sulfo-5,6-dichlorobenzoic acid imide, 3- Imino-1-sulfo-4,5,
6,7-Tetrachlorobenzoic acid imide, 3-imino-1
-Sulfo-4,5,6,7-tetrabromobenzoic acid imide, 3-imino-1-sulfo-4,5,6,7-tetrafluorobenzoic acid imide, 3-imino-1-sulfo-6
-Nitrobenzoic acid imide, 3-imino-1-sulfo-6
-Methoxybenzoic acid imide, 3-imino-1-sulfo-
4,5,7-trichloro-6-methylmercaptobenzoic acid imide, 3-imino-1-sulfonaphthoic acid imide,
3-imino-1-sulfo-5-bromonaphthoic acid imide, 3-imino-2-methyl-4,5,6,7-tetrachloroisoindoline-1-one and the like.

As the fluoran dye, a black fluoran dye is preferable because of the color tone of the color produced by the aromatic isocyanate compound and at least one imino compound having a> C═NH group and the light resistance of the fluorane dye itself. . Examples of such fluorane dyes include 3-diethylamino-6-methyl-7-anilinofluorane, 3
-Dibutylamino-6-methyl-7-anilinofluorane, 3-methylpropylamino-6-methyl-7-anilinofluorane, 3-diethylamino-6-methyl-7
-(2 ', 3'-dimethylanilino) fluorane, 3-
Piperidino-6-methyl-7-anilinofluorane, 3
-Pyrrolidino-6-methyl-7-anilinofluorane,
3-diethylamino-7- (2'-chloroanilino) fluorane, 3-dibutylamino-7- (2'-chloroanilino) fluorane, 3-dibutylamino-7- (2 '
-Fluoroanilino) fluorane 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 particularly 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 and carnauba wax, 2 -Naphthol derivatives such as benzyloxynaphthalene, p-benzylbiphenyl, 4
Biphenyl derivatives such as allyloxybiphenyl, 1,
2-bis (3-methylphenoxy) ethane, 2,2'-
Polyether compounds such as bis (4-methoxyphenoxy) diethyl ether, bis (4-methoxyphenyl) ether, carbonic acid such as diphenyl carbonate, dibenzyl oxalate, oxalic acid di (p-methylbenzyl) ester or oxalic acid diester derivatives, etc. Can be mentioned. These sensitizers can be used alone or in combination of two or more.

As the binder used in the heat-sensitive recording material, starches, hydroxyethyl cellulose, methyl cellulose, carboxymethyl cellulose, gelatin, casein, polyvinyl alcohol, modified polyvinyl alcohol, polyacrylic acid soda, acrylic acid amide / acrylic acid ester copolymer. , Acrylic acid amide / acrylic acid ester / methacrylic acid terpolymer, styrene / maleic anhydride copolymer alkali salt, ethylene /
Water-soluble adhesive such as alkali salt of maleic anhydride copolymer, polyvinyl acetate, polyurethane, polyacrylic acid ester, styrene / butadiene copolymer, acrylonitrile / butadiene copolymer, methyl acrylate / butadiene copolymer, Examples include latex such as ethylene / vinyl acetate copolymer.

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, for the purpose of preventing head wear and sticking, higher fatty acid metal salts such as zinc stearate and calcium stearate, waxes such as paraffin, oxidized paraffin, polyethylene, polyethylene oxide and castor wax, and dioctylsulfosuccinic acid. 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, or a composite sheet in which these are combined can be optionally used. Further, in order to protect the heat-sensitive recording layer, an overcoat layer is provided, or an undercoat layer composed of a single layer or a plurality of layers of pigments or resins is provided between the heat-sensitive recording layer and the support. Various known techniques for making materials can be used.

[0034]

EXAMPLES Next, the present invention will be described in more detail by way of examples. The parts and% 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% polyvinyl alcohol aqueous solution 6
With 0 g, they were dispersed in a Dynomill so that the average particle size was 2 microns. On the other hand, 10 g of 4,4 ′, 4 ″ -triisocyanate-2,5-dimethoxytriphenylamine was dispersed together with 40 g of a 1% aqueous polyvinyl alcohol solution so that the average particle diameter was 2 μm by Dynomill. Furthermore, 3-dibutylamino-6 methyl-7-
10 g of anilinofluorane was dispersed with 40 g of a 1% aqueous solution of polyvinyl alcohol in a Dynomill so that the average particle size was 2 μm. Further, 15 g of zinc 4-n-octyloxycarbonylaminosalicylate was dispersed together with 60 g of a 1% polyvinyl alcohol aqueous solution by Dynomill so that the average particle diameter was 2 μm. After mixing these four dispersions, 200 g of 40% dispersion of calcium carbonate was added, 25 g of 40% dispersion of zinc stearate, 100 g of 20% dispersion of 2-benzyloxynaphthalene, 10% polyvinyl alcohol. Aqueous solution 160
g and 65 g of water were added, and the mixture was thoroughly stirred to give a coating liquid.

(B) Preparation of heat-sensitive coated paper A coating solution having the following composition was applied to a base paper having a basis weight of 40 g / m ^{2 so} as to have a solid content of 9 g / m ² , dried, and heat-sensitive coated. I made engineering 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) was smeared onto the surface of the heat-sensitive coated paper prepared in (B) so that the solid content was 4 g / m ² . A thermosensitive recording material was prepared by drying.

Example 2 A thermosensitive recording material was prepared in the same manner as in Example 1, except that zinc 4-n-octyloxycarbonylaminosalicylate was replaced by zinc 4-fanyloxycarbonylaminosalicylate. .

Example 3 A thermosensitive recording material was prepared in the same manner as in Example 1 except that zinc 4-n-decyloxycarbonylaminosalicylate was used instead of zinc 4-n-octyloxycarbonylaminosalicylate in Example 1. Created.

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

Comparative Example 2 A thermosensitive recording material was prepared in the same manner as in Example 1 except that the zinc 4-n-octyloxycarbonylaminosalicylate of Example 2 was omitted.

Evaluation: [Evaluation of color development characteristics] A printing test was conducted using a facsimile tester TH-PMD manufactured by Okura Electric. Use a thermal head with a dot density of 8 dots / mm and a head resistance of 1290Ω, and use a head voltage of 2
Printing was performed by energizing at 1 V and a pulse width of 1.0 msec, and the color density was measured with a Macbeth RD-918 type reflection densitometer. The results are shown in Table 1.

For the storage characteristics of the background, a writing instrument test was conducted. [Burning resistance test on the background part] In the writing resistance test, after writing the non-image part with a highlighter, the stain on the non-image part after standing for 72 hours at room temperature was visually determined. ◯ indicates that there is almost no stain, and x indicates that coloration has occurred. The results are shown in Table 1.

For the storage characteristics of the image area, a lap resistance test and a writing tool test were performed. [Wrap resistance test of image part] In the lap resistance test, a commercially available wrap was put on the printed part of each heat-sensitive recording material printed with the pulse of 1.0 msec used in the evaluation of the color development property, and 2 g / cm ² from the top.
Was applied, and the state of decoloration of the printed portion after storage for 24 hours in an environment of 40 ° C. was visually determined. ○ indicates that the printed portion remains almost without being erased, Δ indicates that the erased portion of the printed portion is observable but legible, and × indicates that the printed portion is almost erased. This indicates that it is difficult to read the print information.

[Writing resistance test for image area] The writing resistance test was conducted after writing with a highlighter pen on the printing portion of each thermal 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 part after standing for 72 hours at room temperature was visually evaluated. ○ indicates that the printed portion remains almost without being erased, Δ indicates that the erased portion of the printed portion is observable but legible, and × indicates that the printed portion is almost erased. This indicates that it is difficult to read the print information. The results are shown in Table 1.

[0046]

[Table 1]

As shown in Table 1, it can be seen that the heat-sensitive recording materials of the present invention shown in Examples 1 to 3 have good color-developing properties and excellent storage properties in the background and image areas. On the other hand, in Comparative Example 1, although the color development characteristics are excellent, it can be seen that the discoloration of the background part is large and the image part is also discolored. Further, Comparative Example 2 is excellent in the storage characteristics of the background portion and the image portion, but is inferior in the coloring property.

[0048]

As is apparent from the examples, the heat-sensitive recording material of the present invention has the general formula 1 in the three components of the aromatic isocyanate compound, the imino compound and the fluorane dye.
By coating a thermosensitive recording layer composition containing at least one of a salicylic acid derivative or a metal salt thereof on a support, the thermosensitive recording is excellent in heat responsiveness and storage stability of the background portion and the image portion. The material could be obtained.

Claims (1)

[Claims] 1. A heat-sensitive recording comprising, on a support, an aromatic isocyanate compound, an imino compound having at least one> C═NH group which develops a color upon reaction with the isocyanate compound, and a fluorane dye. A heat-sensitive recording material having a layer formed thereon, wherein the heat-sensitive recording layer contains at least one salicylic acid derivative represented by Chemical formula 1 or a metal salt thereof. [Chemical 1] (In the formula, X ₁ and X ₂ represent a hydrogen atom, an alkyl group, an aralkyl group, an aryl group, or a halogen atom, and R represents
It represents an alkyl group, an alkenyl group, an aralkyl group, or an aryl group. )