JPH09142032A - Heat sensitive recording material - Google Patents

Abstract

PROBLEM TO BE SOLVED: To improve the heat resistant property of skin, resistance to flushing of wrap and the storing property of a picture by containing aliphatic isocyanate compound, aliphatic imino compound and organic tin compound. SOLUTION: Aliphatic isocyanate compound means colorless or thin-color aliphatic isocyanate compound or heterocyclic isocyanate compound, provided with a solid body at a normal temperature. Imino compound means colorless or thin-color compound, having a solid body t a normal temperature and at least one imino group shown by a formula I. In the formula, ϕ represents the residue of aliphatic compound capable of forming a conjugation with neighboring C=N while organic tin compound has four pieces of tin in the particle thereof and forms a compound having at least one piece of alkyl group. Heat sensitive coating solution is obtained by adding and mixing binder into the dispersion solution consisting of such aliphatic isocyanate compound, imino compound and the other adding agent while the heat sensitive coating solution is applied on a supporting body to form a heat sensitive recording layer and obtain a heat sensitive recording material.

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 which is excellent in heat resistance of the background, lap fog resistance and image storability.

[0002]

2. Description of the Related Art A heat-sensitive recording material generally comprises a support and a heat-sensitive recording layer containing an electron-donating colorless dye precursor and an electron-accepting developer as main components. By heating with a hot pen, laser light or the like, the colorless dye precursor and the developer react instantaneously to obtain a recorded image. JP-B-43-4160 and JP-B-45-140.
No. 39, etc. Such a heat-sensitive recording material has the advantages that recording can be obtained with a relatively simple device, that it is easy to maintain, and that it does not generate noise, and it is a terminal for measuring recorders, facsimiles, printers, and computer terminals. It is used in a wide range of fields such as machines, labels, ticket vending machines, and other vending machines.

A heat-sensitive recording material using such an electron-donating colorless dye precursor and an electron-accepting color developer has a good appearance.
While it has excellent properties such as good feel, high color density, and various color hues, the thermosensitive color part (recorded image part) is in contact with plastic such as polyvinyl chloride to form plastic. Preservation of records such as disappearance due to plasticizers and additives contained in the product, easy disappearance upon contact with chemicals contained in foods and cosmetics, or fading easily after exposure to sunlight for a short time Is inferior, and due to this drawback, the application is subject to certain restrictions, and its improvement is strongly desired.

Further, in recent years, a high-speed printing apparatus capable of printing in a short time has been developed, and it has excellent thermal response suitable for it.
There has been a demand for a highly sensitive heat-sensitive recording material capable of obtaining a sufficiently colored image even at low energy. Examples of the heat-sensitive recording material capable of obtaining a recorded image having good storability include JP-A-58-38733, JP-A-58-54085, JP-A-58-104959, and JP-A-58-58.
149388, JP-A-59-115888, JP-A-59-115888, and U.S. Pat. No. 4,521,793 describe a heat-sensitive agent mainly containing an aromatic isocyanate and an imino compound. A recording material comprising a combination of heat sensitive agents is disclosed.

However, these thermal recording materials are
Excellent in storage stability of recorded images, but sensitivity (thermal response)
Was bad. For the purpose of improving the sensitivity of this heat-sensitive recording material, JP-A-59-135186 discloses a heat-sensitive recording material comprising an aromatic isocyanate, an imino compound, a leuco dye and an acidic substance which reacts with the leuco dye to develop a color. However, there is a problem in practical use because the heat resistance of the background and the resistance to wrapping are poor.

In addition to these, JP-A-60-262686
Japanese Unexamined Patent Publication Nos. Hei 2-103180 and Hei 4-2.
Japanese Patent No. 32777 discloses a heat-sensitive recording material comprising three components of an aromatic isocyanate, an imino compound and a specific fluorane compound, but an improvement in sensitivity is clearly recognized, but the lap fog resistance is poor. However, it is not sufficient for practical use.

Further, in Japanese Patent Publication No. 5-076918, a heat-sensitive recording in which the storability of the background is improved by containing an aniline derivative as a third component in a combination of a color former composed of an aromatic isocyanate compound and an imino compound. Although a material is disclosed, in a heat-sensitive recording material containing a leuco dye and an acidic substance that develops a color by reacting with the leuco dye in addition to these three components, a physical property balance between heat resistance of the background and resistance to lap covering is provided. Is bad and there is a problem in practical use.

[0008]

SUMMARY OF THE INVENTION It is an object of the present invention to provide a heat-sensitive recording material which is excellent in heat resistance of the background and lap fog resistance and in image storability.

[0009]

DISCLOSURE OF THE INVENTION The inventors of the present invention have earnestly studied in order to obtain a heat-sensitive recording material having excellent heat resistance of the background and resistance to wrapping, and excellent image storability. In a heat-sensitive recording material containing a compound and an aromatic imino compound in the heat-sensitive recording layer, it was found that the heat resistance of the background and the lap fog resistance can be significantly improved by containing a specific organotin compound, and the present invention is completed. Came to. That is, the present invention is a heat-sensitive agent containing an aromatic isocyanate compound, an aromatic imino compound and an organic tin compound. Alternatively, it is a heat-sensitive recording material in which a heat-sensitive recording layer containing this heat-sensitive agent is provided on a support. Or
It is a heat-sensitive agent containing an aromatic isocyanate compound, an aromatic imino compound, a leuco dye, an acidic substance that develops a color by reacting with the leuco dye, and an organotin compound. Alternatively, it is a heat-sensitive recording material in which a heat-sensitive recording layer containing this heat-sensitive agent is provided on a support. Alternatively, it is a heat-sensitive agent containing an aromatic isocyanate compound, an aromatic imino compound, a leuco dye, an acidic substance that develops a color by reacting with the leuco dye, an amine compound and an organotin compound. Alternatively, it is a heat-sensitive recording material in which a heat-sensitive recording layer containing this heat-sensitive agent is provided on a support. Alternatively, the organotin compound is any one of the above heat-sensitive agents, which is a compound represented by the following general formula (1).

(R) _a Sn (X) _b (1) (wherein R represents an alkyl group, and X represents a halogen, oxygen, an alkyl group, an alkylmercapto group, or a carboxylic acid residue. Here, a, b is an integer and a + b = 4 (a> 0,
b ≧ 0) is satisfied. Or a heat-sensitive recording material having a heat-sensitive recording layer containing the heat-sensitive agent on a support.

The present invention will be described in detail below. The aromatic isocyanate compound used in the present invention refers to 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 isocyanate compounds are 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-diisocyanate , Azobenzene-4,4'-diisocyanate, diphenyl ether-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, bilen-3,8-diisocyanate , Naphthalene-
1,3,7-triisocyanate, biphenyl-2,2
4,4'-triisocyanate, 4,4 ', 4 "-triisocyanato-2,5-dimethoxytriphenylamine, 4,4', 4" -triisocyanatotriphenylamine, p-dimethylaminophenyl There are isocyanate, tris (4-phenylisocyanate) thiophosphate and the like. If desired, these isocyanates 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, 1- It may be used in the form of isocyanurate, which is a dimer and trimer of methylbenzene-2,4-diisocyanate, or may be used as a polyisocyanate adducted with various polyols. is there.

Of these, the triphenylamine derivative isocyanate is particularly preferable, and 4,4 ',
4 ″ -triisocyanato-2,5-dimethoxytriphenylamine is preferred. In order to prepare a heat-sensitive recording material, the heat-sensitive recording layer is prepared by coating these on a support together with other necessary components in the form of a dispersion liquid. The dispersion liquid is prepared by pulverizing one or more of these aromatic isocyanates in an aqueous solution containing a compound having a dispersive ability such as a water-soluble polymer and a surfactant. It is possible to add alcohols at the time of dispersion.

The imino compound used in the present invention has at least one imino group represented by the following formula (2),

[0014]

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A compound represented by the general formula shown in the following formula (3), which is a colorless or light-colored compound which is solid at room temperature. Specific examples are shown below. Two or more imino compounds can be used in combination depending on the purpose.

[0016]

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(Φ is an aromatic compound residue capable of forming a conjugated system with adjacent C = N) 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-methyl Mercapto-isoindoline-1-one, 3-imino-6-nitroisoindoline-1-one, 3-imino-isoindoline-1-spiro-dioxolan, 1,1-dimethoxy-3-imino-isoindoline, , 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'-dichlorobenzothiazolyl-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- (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-iminoisoindoline, 1-
(Benzimidazolyl-2'-imino) -3-imino-
4,5,6,7-tetrachloroisoindoline, 1-
(2 ', 4'-Dinitrophenylhydrazone) -3-imi 111 noisoindoline, 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-
(Cyanocarbonamidethylene) -3-iminoisoindoline, 1- (cyanocarbomethoxymethylene) -3
-Iminoisoindoline, 1- (cyanocarboethoxymethylene) -3-iminoisoindoline, 1- (cyano-N-phenylcarbamoylmethylene) -3-iminoisoindoline, 1- [cyano-N- (3'-methyl Phenyl) -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-pyradiisoindoline, 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 imide, 3-imino-1
-Sulfo-5-bromonaphthoic imide, 3-imino-
2-methyl-4,5,6,7-tetrachloroisoindoline-1-one and the like.

Of these, iminoisoindoline derivatives are particularly preferable, and 1,3-diimino-4,
5,6,7-tetrachloroisoindoline, 3-imino-4,5,6,7-tetrachloroisoindoline-1-
On, 1,3-diimino-4,5,6,7-tetrabromoisoindoline is preferred. The organotin compound used in the present invention is a compound having tetravalent tin in the molecule and having at least one alkyl group. As a property, it is a solid or liquid colorless or light-colored compound at room temperature, and a non-toxic or low-toxic compound is preferable. For example, di-n-
Octyl tin bis (thioglycolic acid isooctyl ester) salt, di-n-octyl tin bis (thioglycolic acid-
2-ethylhexyl ester) salt, mono-n-octyltin tris (thioglycolic acid isooctyl ester) salt,
Mono-n-octyltin tris (thioglycolic acid-2-
Octyl tin mercapto such as ethylhexyl ester) salt,
Dimethyltin bis (isooctyl mercaptoacetate)
Such as methyltin mercapto, di-n-octyltin bis (2
Octyltin alkylmalates such as ethylhexylmalate, di-n-octyltinmalate polymers, di-n-
Octyl tin dilaurate, di-n-octyl tin distearate, di-n-octyl tin diversate, tetra-
Examples include n-octyltin, poly (thiobis-n-butyltin sulfide), di-n-octyltin oxide, di-n-octyltin dichloride and the like. Organotin compounds may be used alone or as a mixture, and the heat resistance of the background,
In order to improve the lap fog resistance in a well-balanced manner, the amount is preferably 1 to 500% by weight based on the aromatic isocyanate compound. If the content of the organic tin compound is less than 1% by weight based on the aromatic isocyanate compound, sufficient lap fog resistance cannot be obtained. Further, even if it is used in an amount exceeding 500% by weight, the performance is not improved, and the cost is disadvantageous.

The leuco dye used in the present invention and the acidic substance which develops a color by reacting with the leuco dye are compounds already known as color formers used in heat-sensitive recording materials and are not particularly limited. For example: Specific examples of the leuco dye will be shown. (1) Triarylmethane compound 3,3-bis (p-dimethylaminophenyl) -6-dimethylaminophthalide (crystal violet lactone), 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-phenylindole-
3-yl) phthalide, 3,3-bis (1,2-dimethylindol-3-yl) -5-dimethylaminophthalide, 3,3-bis (1,2-dimethylindole-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.

(2) Diphenylmethane compound 4,4-bis-dimethylaminophenylbenzhydrylbenzyl ether, N-halophenylleuco auramine, N-2,4,5-trichlorophenyl leuco auramine and the like. (3) Xanthene compounds rhodamine B anilinolactam, rhodamine Bp-chloroanilinolactam, 3-diethylamino-7-dibenzylaminofluoran, 3-diethylamino-7-octylaminofluoran, 3-diethylamino-7 -Phenylfluoran, 3-diethylamino-7-chlorofluoran, 3-diethylamino-6-chloro-7-methylfluoran, 3-diethylamino-7- (3,4-dichloroanilino) fluoran, 3-diethylamino- 7
-(2-chloroanilino) fluorane, 3-diethylamino-6-methyl-7-anilinofluorane, 3- (N
-Ethyl-N-tolyl) amino-6-methyl-7-anilinofluoran, 3-piperidino-6-methyl-7-anilinofluoran, 3- (N-ethyl-N-tolyl) amino-6 Methyl-7-phenethylfluoran, 3-diethylamino-7- (4-nitroanilino) fluoran, 3-dibutylamino-6-methyl-7-anilinofluoran, 3- (N-methyl-N-propyl) amino-
6-methyl-7-anilinofluoran, 3- (N-ethyl-N-isoamyl) amino-6-methyl-7-anilinofluoran, 3- (N-methyl-N-cyclohexyl) amino-6 Methyl-7-anilinofluoran, 3
-(N-ethyl-N-tetrahydrofuryl) amino-6
-Methyl-7-anilinofluoran and the like.

(4) Thiazine Compounds Benzoyl leuco methylene blue, p-nitrobenzoyl leuco methylene blue and the like. (5) Spiro compound 3-methylspirodinaphthopyran, 3-ethylspirodinaphthopyran, 3,3-dichlorospirodinaphthopyran, 3-benzylspirodinaphthopyran, 3-methylnaphtho- (3-methoxybenzo) Spiropyran, 3-propylspirobenzopyran and the like.

These leuco dyes may be used alone or in combination. Next, specific examples of acidic substances will be shown. Generally, an electron-accepting substance used for thermal paper is used, and a phenol derivative, an aromatic carboxylic acid derivative or a metal compound thereof, an N, N-diarylthiourea derivative and the like are particularly preferable. Particularly preferred is a phenol derivative, specifically, 2,2-bis (4-hydroxyphenyl) propane, 2,2-bis (4-hydroxyphenyl) butane, 2,2-bis (4-hydroxyphenyl). ) Pentane, 2,2-bis (4-hydroxyphenyl) heptane, 1,1-bis (4-hydroxyphenyl) cyclohexane, bis (4-hydroxyphenyl)
Butyl acetate, bis (4-hydroxyphenyl) benzyl acetate, bis (4-hydroxyphenyl) sulfone, bis (3-methyl-4-hydroxyphenyl) sulfone, 4
-Hydroxyphenyl-4'-methylphenyl sulfone, 3-chloro-4-hydroxyphenyl-4'-methylphenyl sulfone, 3,4-dihydroxyphenyl-
4'-methylphenyl sulfone, 4-isopropylphenyl-4'-hydroxyphenyl sulfone, 4-isopropyloxyphenyl-4'-hydroxyphenyl sulfone, bis (2-allyl-4-hydroxyphenyl) sulfone, 4-hydroxyphenyl- 4'-benzyloxyphenyl sulfone, 4-isopropylphenyl-4 '
-Hydroxyphenyl sulfone, bis (2-methyl-3)
-Tert. -Butyl-4-hydroxyphenyl) sulfide, ethyl 4-hydroxybenzoate. Benzyl 4-hydroxybenzoate. 4-hydroxybenzoic acid (4'-
Chlorobenzyl), 1,2-bis (4'-hydroxybenzoic acid) ethyl, 1,5-bis (4'-hydroxybenzoic acid) ventil, 1,6 bis (4'-hydroxybenzoic acid) hexyl, 3- Examples thereof include dimethyl hydroxyphthalate, stearyl gallate, and lauryl gallate.

Among these, particularly when 2,2-bis (4-hydroxyphenyl) propane is used, the balance between heat resistance and lap fog resistance is remarkably improved. The acidic substances may be used alone or as a mixture, and in order to obtain a sufficient thermal response, the acidic substance may be added to the leuco dye at 50 to 50%.
It is preferably 250% by weight. The weight ratio of the color former system consisting of the leuco dye and the acidic substance and the color former system consisting of the imino compound and the aromatic isocyanate compound is 1: 9 to 9: 1 in order to obtain sufficient color developing sensitivity. It is more preferable that the ratio is 1: 3 to 4: 1.

The amine compound used in the present invention is
It is a colorless or light-colored substance having at least one primary, secondary, or tertiary amino group. Specific examples of these amine compounds include beef tallow or coconut oil-derived aliphatic amines, methyl p-aminobenzoate, ethyl p-aminobenzoate, n-propyl p-aminobenzoate, and p-aminobenzoic acid. Acid-iso-propyl, butyl p-aminobenzoate, dodecyl p-aminobenzoate, p-
Benzyl aminobenzoate, o-aminobenzophenone,
m-aminoacetophenone, m-aminobenzamide,
o-aminobenzamide, p-aminobenzamide, p
-Amino-N-methylbenzamide, 3-amino-4-
Methylbenzamide, 3-amino-4-methoxybenzamide, 3-amino-4-chlorobenzamide, p-
(N-phenylcarbamoyl) aniline, p- [N-
(4-chlorophenyl) carbamoyl] aniline, p-
[N- (4-aminophenyl) carbamoyl] aniline, 2-methoxy-5- (N-phenylcarbamoyl)
Aniline, 2-methoxy-5- [N- (2'-methyl-
3'-chlorophenyl) carbamoyl] aniline, 2-
Methoxy-5- [N- (2'-chlorophenyl) carbamoyl] aniline, 5-acetylamino-2-methoxyaniline, 4-acetylaminoaniline, 4- (N-methyl-N-acetylamino) aniline, 2,5 -Diethoxy-4- (N-benzoylamino) aniline, 2,5
-Dimethoxy-4- (N-benzoylamino) aniline, 2-methoxy-4- (N-benzoylamino) -5
-Methylaniline, 4-sulfamoylaniline, 3-
Sulfamoylaniline, 2- (N-ethyl-N-phenylaminosulfonyl) aniline, 4-dimethylaminosulfonylaniline, 4-diethylaminosulfonylaniline, sulfathiazole, 4-aminodiphenylsulfone, 2-chloro-5-N -Phenylsulfamoylaniline, 2,5-dimethoxy-4-N-phenylsulfamoylaniline, 2-methoxy-5-benzylsulfonylaniline, 2-phenoxysulfonylaniline,
2- (2'-chlorophenoxy) sulfonylaniline,
3-anilinosulfonyl-4-methylaniline, bis [4- (m-aminophenoxy) phenyl] sulfone,
Bis [4- (p-aminophenoxy) phenyl] sulfone, bis [3-methyl-4- (p-aminophenoxy)
Phenyl] sulfone, 3,3'-dimethoxy-4,4 '
-Diaminobiphenyl, 3,3'-dimethyl-4,4 '
-Diaminobiphenyl, 2,2'-dichloro-4,4 '
-Diamino-5,5'-dimethoxybiphenyl, 2,
2 ', 5,5'-tetrachloro-4,4'-diaminobiphenyl, ortho-tolidine sulfone, 2,4'-diaminobiphenyl, 2,2'-diaminobiphenyl, 4,
4'-diaminobiphenyl, 2,2'-dichloro-4,
4'-diaminobiphenyl, 3,3'-dichloro-4,
4'-diaminobiphenyl, 2,2'-dimethyl-4,
4'-diaminobiphenyl, 4,4'-thiodianiline, 2,2'dithiodianiline, 4,4'-dithiodianiline, 4,4'-diaminodiphenyl ether, 3,
3'-diaminodiphenyl ether, 3,4'-diaminodiphenyl ether, 3,4'-diaminodiphenylmethane, bis (3-amino-4-chlorophenyl) sulfone, bis (3,4-diaminophenyl) sulfone, bis (4-amino) Phenyl) sulfone, bis (3-aminophenyl) sulfone, 3,4'-diaminodiphenyl sulfone, 3,3'-diaminodiphenylmethane, 4,
4'-ethylenedianiline, 4,4'diamino-2,
2'-dimethyldibenzyl, 4,4'-diamino-3,
3'-dichlorodiphenylmethane, 3,3'-diaminobenzophenone, 4,4'-diaminobenzophenone,
1,4-bis (4-aminophenoxy) benzene, 1,
3-bis (4-aminophenoxy) benzene, 1,3-
Bis (3-aminophenoxy) benzene, 9,9-bis (4-aminophenyl) fluorene, 2,2-bis (4
-Aminophenoxyphenyl) propane, 4,4'-bis (4-aminophenoxy) diphenyl, 3,3 ',
4,4'-tetraaminodiphenyl ether, 3,
3 ', 4,4'-tetraaminodiphenyl sulfone,
3,3'4,4'-tetraaminobenzophenone, 4-
Aminobenzonitrile, 3-aminobenzonitrile, p
-Phenylenediamine, m-phenylenediamine, 4-
Phenoxyaniline, 3-phenoxyaniline, 4,
Aniline derivatives such as 4'-diaminodiphenylmethane, 4,4'-methylenebis-O-toluidine, 4,4 '-(p-phenyleneisopropylidene) -bis- (2,6-xylidine), and further acetoguanamine, 2 , 4-
Diamino-6- [2'-methylimidazolyl- (1)]
Ethyl-S-triazine, 4-aminopyridine, 2,3
-Heterocyclic compounds such as diaminopyridine, 2,3,5-triaminopidine, and tetrakis (1,2,2,
6,6-pentamethyl-4-piperidyl) -1,2,2
3,4-butanetetracarboxylate, tetrakis (2,2,6,6-tetramethyl-4-piperidyl)-
1,2,3,4-butane tetracarboxylate, 1,
2,3,4-butanetetracarboxylic acid ・ 1,2,2
6,6-pentamethyl-4-piperidinol.β, β,
β ′, β′-tetramethyl-3,9- (2,4,8,1
0-tetraoxaspiro [5,5] undecanediethanol condensate, 1,2,3,4-butanetetracarboxylic acid-2,2,6,6-tetramethyl-4-piperidinol-β, β, β ', β'-tetramethyl-3,9- (2,
4,8,10-Tetraoxaspiro [5,5] undecanediethanol condensate, poly [{6- (1,1,3,3
-Tetramethylbutyl) amino-1,3,5-triazine-2,4-diyl} {(2,2,6,6-tetramethyl-4-piperidyl) imino} hexamethylene {(2,
2,6,6-Tetramethyl-4-piperidyl) imino}], N, N′-bis (3-aminopropyl) ethylenediamine · 2,4-bis [N-butyl-N- (1,
2,2,6,6-Pentamethyl-4-piperidyl) amino] -6-chloro-1,3,5-triazine condensate, 2
-(3,5-Di-t-butyl-4-hydroxybenzyl) -2-n-butylmalonic acid-bis (1,2,2,2)
6,6-pentamethyl-4-piperidyl), succinic acid-
Hindered amine compounds such as bis (2,2,6,6-tetramethyl-4-piperidinyl) ester are mentioned.

Among the above amine compounds, an aniline derivative having at least one amino group represented by the following formula (4) is preferable.

[0026]

Embedded image

(Wherein R ₄ , R ₅ , R ₆ and R ₇ are
Hydrogen, a halogen, an alkyl group, an alkoxy group or an amino group, X ₂ , X ₃ represent an amino group or the formula (5),

[0028]

Embedded image

Y ₁ is --SO _2- , --O--,-(S) _{n.
-, - (CH 2) n} -, - C -, - CONH-, or an expression (6),

[0030]

Embedded image

In addition, it indicates the case where it does not exist. n is 1, 2
Represents ) The amine compounds may be used alone or as a mixture, and in order to improve the heat resistance of the background and the resistance to wrapping in a well-balanced manner, 1 to 500% by weight based on the aromatic isocyanate compound is used. Preferably there is. If the content of the amine compound is less than 1% by weight with respect to the aromatic isocyanate compound, sufficient lap fog resistance cannot be obtained. Further, even if it is used in an amount exceeding 500% by weight, the performance is not improved, and the cost is disadvantageous.

The heat-sensitive recording material according to the present invention may contain a heat-fusible substance in order to improve its sensitivity. Those having a melting point of 60 ° C to 180 ° C are preferred,
Particularly, those having a melting point of 80 ° C to 140 ° C are preferable.
For example, benzyl p-benzyloxybenzoate, stearamide, palmitamide, N-methylol stearamide, β-naphthylbenzyl ether, N
-Stearyl urea, N, N'-distearyl urea,
β-naphthoic acid phenyl ester, 1-hydroxy-2
-Naphthoic acid phenyl ester, β-naphthol (p-
Methylbenzyl) ether, 1,4-dimethoxynaphthalene, 1-methoxy-4-benzyloxynaphthalene,
N-stearoylurea, 4-benzylbiphenyl,
1,2-di (m-methylphenoxy) ethane, 1-phenoxy-2- (4-chlorophenoxy) ethane, 1,4
-Butanediol phenyl ether, dimethyl terephthalate, metaterphenyl, dibenzyl p-methyl oxalate, oxalic acid (p-chlorobenzyl) ester and the like can be mentioned.

The above-mentioned heat-fusible substances may be used alone or as a mixture, and in order to obtain a sufficient thermal response, 10 to 10 relative to the aromatic isocyanate compound is used.
It is preferable to use 100% by weight, and further 100 to 6
It is more preferable to use 100% by weight. In order to use these leuco dyes, acidic substances, imino compounds, heat-fusible substances, and amine compounds as heat-sensitive recording materials, it is necessary to form them in the form of dispersion liquids like the aromatic isocyanate compounds. The dispersion is prepared in the same manner as in the case of the aromatic isocyanate compound.

The dispersion liquid of the aromatic isocyanate compound, the dispersion liquid of the imino compound and the dispersion liquid of other additives thus obtained are mixed with a binder to prepare a heat-sensitive coating liquid. The heat-sensitive recording material of the present invention can be obtained by applying the heat-sensitive coating liquid on the support by a coating method such as an air knife, a blade, or curtain coating to form a heat-sensitive recording layer.

The heat-sensitive recording material according to the present invention is, as described above, provided with a heat-sensitive recording layer for coloring by heating on a support. Paper is mainly used as the support, but in addition to paper, various non-woven fabrics, synthetic resin films, laminated paper,
Synthetic paper, metal foil, or a composite sheet in which these are combined can be arbitrarily used according to the purpose. The layer structure of the heat-sensitive recording layer may be a single layer or a plurality of multilayer structures. In the case of a multilayer, an intermediate layer may be interposed between each layer. Further, a protective layer may be provided on this layer. This recording layer can be obtained by mixing each aqueous dispersion obtained by finely pulverizing each color-forming component, a binder and the like, applying the mixture on a support, and drying. In this case, for example, each color-forming component may be contained one layer at a time to form a multilayer structure.

As the binder, water-soluble materials such as starches, hydroxyethyl cellulose, methyl cellulose, carboxymethyl cellulose, gelatin, casein, polyvinyl alcohol, modified polyvinyl alcohol, styrene-maleic anhydride copolymer, ethylene-maleic anhydride copolymer, etc. Examples thereof include latex-based water-insoluble binders such as binders, styrene-butadiene copolymers, acrylonitrile-butadiene copolymers and methyl acrylate-butadiene copolymers.

Further, in the heat-sensitive recording layer, pigments such as diatomaceous earth, talc, kaolin, calcined kaolin, calcium carbonate, magnesium carbonate, titanium oxide, zinc oxide, silicon oxide, aluminum hydroxide, urea-formalin resin, etc. , Higher fatty acid metal salts such as zinc stearate and calcium stearate, waxes such as paraffin, oxidized paraffin, polyethylene, polyethylene oxide, stearamide, and castor wax for the purpose of preventing head wear and sticking, and dioctylsulfosuccinic acid. A dispersant such as sodium acid salt, a benzophenone-based or benzotriazole-based ultraviolet absorber, a surfactant, a fluorescent dye, and the like may be contained.

[0038]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described in more detail with reference to the following examples.

[0039]

Example 1 4,4 ', 4 "-triisocyanate-
175 g of 2,5-dimethoxyphenylamine was added to 325 g of a 5.4% by weight polyvinyl alcohol aqueous solution, and a small amount of an antifoaming agent (manufactured by Nissin Chemical Industry Co., Ltd., Sirphenol 104E) was also added to produce Dynomill (Shinmaru Enterprise). (Manufactured by the same company) was pulverized and dispersed under the conditions of a rotation speed of 2000 rpm and 15 passes to obtain a dispersion liquid.

Separately from this dispersion, 40 g of an imino compound, 1,3-diimino-4,5,6,7-tetrachloroisoindoline, was added to 160 g of a 10% by weight aqueous polyvinyl alcohol solution, and a sand grinder (Bessel capacity) was used. 400ml, made by IMEX), rotation speed 2000r
It was pulverized and dispersed at pm for 3 hours to obtain a dispersion liquid. Also,
2 g of n-octyl tin dimalate (Kyodo Pharmaceutical Co., Ltd., KS
1000) 5% by weight polyvinyl alcohol aqueous solution 4
g, 2.75 g of water, and 1.25 g of ethanol were dispersed in a paint shaker for 4 hours to obtain a dispersion liquid.

Further, 3-dibutylamino-6-methyl-
70 g of 7-anilinofluoran was added to 130 g of an aqueous 8% by weight polyvinyl alcohol solution, and the mixture was pulverized and dispersed for 3 hours at a rotation speed of 2000 rpm with a sand grinder (Vessel capacity: 400 ml, manufactured by AIMEX Co., Ltd.) to obtain a dispersion liquid. Also, 70 g of 2,2-bis (4-hydroxyphenyl) propane was added to a 1 wt% polyvinyl alcohol aqueous solution 1
Add to 30 g, sand grinder (vessel capacity 4
00ml, manufactured by Imex Corporation), 2000 rpm
Was pulverized and dispersed for 3 hours to obtain a dispersion liquid.

Also, 70 g of parabenzyl biphenyl was added to 8
Add to 130 g of weight% polyvinyl alcohol aqueous solution,
A sand grinder (400 ml in vessel capacity, manufactured by AIMEX) was pulverized and dispersed for 3 hours at a rotation speed of 2000 rpm to obtain a dispersion liquid. 50g of calcium carbonate
A dispersion was obtained by dispersing in 50 g of water. These dispersions were added with 4,4 ', 4 "-triisocyanato-2,5-dimethoxytriphenylamine dispersion 7.1 parts by weight, 1,3-
Diimino-4,5,6,7-tetrachloroisoindoline dispersion 10.7 parts by weight, di-n-octyltin dimaleate dispersion 7.1 parts by weight, 3-dibutylamino-6-
Methyl-7-anilinofluorane dispersion liquid 13.3 parts by weight, 2,2-bis (4-hydroxyphenyl) propane dispersion liquid 33.4 parts by weight, parabenzyl biphenyl dispersion liquid 33.4 parts by weight, calcium carbonate 53 parts by weight of dispersion liquid,
Further, 30 parts by weight of a zinc stearate dispersion having a solid content concentration of 16% by weight and 45 parts by weight of a 15% by weight polyvinyl alcohol aqueous solution as a binder were stirred and mixed to obtain a coating liquid.

This coating solution was coated on a base paper having a weight of 50 g / m ² with a bar coater of rod number 10, dried and treated with a super calendar to obtain a heat-sensitive recording material. The sensitivity was evaluated with a printing tester manufactured by Okura Electric Co., Ltd., and the color density was measured with a thermal head of KJT-256-8MGF1 manufactured by Kyocera at an applied voltage of 24 V and a pulse width of 1.5 msec. The result was a good optical density of 1.4.

To evaluate the degree of heat discoloration of the background (heat resistance), the heat-sensitive recording material was left in an environment of 60 ° C. and 25% RH for 24 hours, and the discoloration density of the background was measured. The result was a good optical density of 0.08. To evaluate the resistance to wrapping, the heat-sensitive recording material was sandwiched between vinyl chloride wraps, a load of 300 g / cm ² was applied from above, and the material was left at 40 ° C. for 24 hours to measure the discoloration density of the background. The result is an optical density of 0.1
It was as good as 0.

To evaluate the image storability, a sample printed with a thermal recording material at a load pressure of 24 V and a pulse width of 1.5 msec was subjected to the same treatment as in the lap fog resistance test, and the change was visually determined. The result was good with little discoloration. The results are shown in Table 1.

[0046]

Example 2 The same treatment as in Example 1 was carried out except that the di-n-octyltin dimalate of Example 1 was changed to di-n-octyltin dilaurate (OT-1 manufactured by Asahi Denka Co., Ltd.). A thermosensitive recording material was prepared and evaluated. The results are summarized in Table 1.

[0047]

Example 3 The di-n-octyltin dimaleate of Example 1 was converted to di-n-octyltin oxide (Sankoki Gosei Co., Ltd.).
Manufactured by StanOO), and a thermal recording material was prepared by the same process as in Example 1 and evaluated. The results are summarized in Table 1.

[0048]

Example 4 To the coating liquid of Example 1, 40 g of 3,3′-diaminodiphenyl sulfone was added to 160 g of a 10% by weight aqueous polyvinyl alcohol solution, and a sand grinder (Vessel capacity 400 ml, manufactured by AIMEX Co., Ltd.) was rotated at a rotation speed of 20.
A thermosensitive recording material was prepared and evaluated in the same manner as in Example 1 except that 7.1 parts by weight of the dispersion obtained by pulverizing and dispersing at 00 rpm for 3 hours was added. The results are summarized in Table 1.

[0049]

Example 5 To the coating solution of Example 2, 40 g of 3,3′-diaminodiphenyl sulfone was added to 160 g of a 10 wt% polyvinyl alcohol aqueous solution, and a sand grinder (Vessel capacity 400 ml, manufactured by AIMEX Co., Ltd.) was rotated at a rotation speed of 20.
A thermosensitive recording material was prepared and evaluated in the same manner as in Example 2 except that 7.1 parts by weight of the dispersion obtained by pulverizing and dispersing at 00 rpm for 3 hours was added. The results are summarized in Table 1.

[0050]

Example 6 To the coating solution of Example 3, 40 g of 3,3′-diaminodiphenyl sulfone was added to 160 g of a 10 wt% polyvinyl alcohol aqueous solution, and a sand grinder (Vessel capacity 400 ml, manufactured by AIMEX Co., Ltd.) was rotated at a rotation speed of 20.
A thermosensitive recording material was prepared and evaluated in the same manner as in Example 3 except that 7.1 parts by weight of the dispersion obtained by pulverizing and dispersing at 00 rpm for 3 hours was added. The results are summarized in Table 1.

[0051]

Example 7 In Example 4, 4,4 ', 4 "-triisocyanato-2,5-dimethoxytriphenylamine 175 was used.
g was added to a mixture of 272.5 g of 6.4 wt% polyvinyl alcohol and 52.5 g of ethanol, and the heat-sensitive recording material was prepared in the same manner as in Example 4 except that it was pulverized and dispersed in a Dynomill at 2000 rpm and 30 passes. Created and evaluated. The results are summarized in Table 1.

[0052]

Example 8 The same treatment as in Example 1 was carried out except that 3-dibutylamino-6-methyl-7-anilinofluorane and 2,2-bis (4-hydroxyphenyl) propane were not used in Example 1. Then, a thermosensitive recording material was prepared and evaluated. The results are summarized in Table 1.

[0053]

Example 9 The same treatment as in Example 2 was carried out except that 3-dibutylamino-6-methyl-7-anilinofluorane and 2,2-bis (4-hydroxyphenyl) propane were not used in Example 2. Then, a thermosensitive recording material was prepared and evaluated. The results are summarized in Table 1.

[0054]

Example 10 The same treatment as in Example 3 was conducted except that 3-dibutylamino-6-methyl-7-anilinofluorane and 2,2-bis (4-hydroxyphenyl) propane were not used in Example 3. Then, a thermosensitive recording material was prepared and evaluated. The results are summarized in Table 1.

[0055]

Example 11 The same treatment as in Example 4 was performed except that 3-dibutylamino-6-methyl-7-anilinofluorane and 2,2-bis (4-hydroxyphenyl) propane were not used in Example 4. Then, a thermosensitive recording material was prepared and evaluated. The results are summarized in Table 1.

[0056]

Example 12 The same treatment as in Example 5 was performed except that 3-dibutylamino-6-methyl-7-anilinofluorane and 2,2-bis (4-hydroxyphenyl) propane were not used in Example 5. Then, a thermosensitive recording material was prepared and evaluated. The results are summarized in Table 1.

[0057]

Example 13 The same treatment as in Example 6 was performed except that 3-dibutylamino-6-methyl-7-anilinofluorane and 2,2-bis (4-hydroxyphenyl) propane were not used in Example 6. Then, a thermosensitive recording material was prepared and evaluated. The results are summarized in Table 1.

[0058]

COMPARATIVE EXAMPLE 1 A thermal recording material was prepared in the same manner as in Example 1 except that di-n-octyltin dimaleate was not used, and evaluated. The results are summarized in Table 1.

[0059]

Comparative Example 2 A thermal recording material was prepared in the same manner as in Example 4 except that the di-n-octyltin dimaleate was not used, and evaluated. The results are summarized in Table 1.

[0060]

Comparative Example 3 A thermal recording material was prepared in the same manner as in Example 8 except that di-n-octyltin dimaleate was not used in Example 8 and evaluated. The results are summarized in Table 1.

[0061]

Comparative Example 4 A thermosensitive recording material was prepared and evaluated in the same manner as in Example 11 except that di-n-octyltin dimaleate was not used in Example 11. Table 1 summarizes the results
Shown in

[0062]

[Table 1]

[0063]

EFFECT OF THE INVENTION It is possible to obtain a heat-sensitive recording material which is excellent in image storability, heat resistance and lap fog resistance.

Claims (8)

[Claims] 1. A heat-sensitive agent containing an aromatic isocyanate compound, an aromatic imino compound and an organic tin compound. 2. A heat-sensitive recording material having a heat-sensitive recording layer containing the heat-sensitive agent according to claim 1 on a support. 3. A heat-sensitive agent containing an aromatic isocyanate compound, an aromatic imino compound, a leuco dye, an acidic substance that develops a color by reacting with the leuco dye, and an organotin compound. 4. A heat-sensitive recording material comprising a heat-sensitive recording layer containing the heat-sensitive agent according to claim 3 on a support. 5. A heat-sensitive agent containing an aromatic isocyanate compound, an aromatic imino compound, a leuco dye, an acidic substance that develops a color by reacting with the leuco dye, an amine compound and an organotin compound. 6. A heat-sensitive recording material comprising a heat-sensitive recording layer containing the heat-sensitive agent according to claim 5 on a support. 7. The heat-sensitive agent according to claim 1, 3 or 5, wherein the organotin compound is a compound represented by the following general formula (1). (R) _a Sn (X) _b (1) (wherein R represents an alkyl group, X represents a halogen, oxygen, an alkyl group, an alkylmercapto group, or a carboxylic acid residue. Here, a and b are integers. And a + b = 4 (a> 0,
b ≧ 0) is satisfied. ) 8. A heat-sensitive recording material comprising a heat-sensitive recording layer containing the heat-sensitive agent according to claim 7 on a support.