JPH07228053A - Thermal recording material - Google Patents

Abstract

PURPOSE:To embody raw preservability and the stability of a developed color image and the enhancement of sensitivity and printing quality by arranging a thermal color forming layer containing a colorless or light-colored electron donating dye precursor, an isocyanate compd. and an amino compd. on a support. CONSTITUTION:A thermal recording material is constituted by arranging a thermal color forming layer containing a colorless or light-colored electron donating dye precursor, an isocyanate compd. and an amino compd. on a support. The isocyanatre compd. and an amino compd. are reacted at the time of heating to form a urea compd. which in turn acts as an electron acceptive compd. to increase sensitivity. By this constitution, the thermal recording material good in raw preservability, forming a developed color image good in stability, having high sensitivity and excellent in printing quality is obtained. The isocyanate compd. is an aromatic isocyanate compd. having two or more -NCO groups and the amino compd. has two or more -NH2 groups.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a heat-sensitive recording material, and more particularly to a heat-sensitive recording material having improved color forming properties, raw storability and stability of color images.

[0002]

2. Description of the Related Art Recording materials using colorless or light-colored electron-donating dye precursors and electron-accepting compounds are already well known as pressure-sensitive paper, heat-sensitive paper, light-sensitive pressure-sensitive paper, heat-sensitive recording paper, heat-sensitive transfer paper and the like. , For example British Patent No. 2,14
0,449, U.S. Pat. Nos. 4,480,052, 4,436,920, JP-B-60-23992, JP-A-57-179836, and JP-A-60-123556.
No. 60-123557 and the like.

Particularly, regarding the heat-sensitive recording material, Japanese Patent Publication No. S43
-4160, 45-14039 and the like. These thermal recording materials are facsimiles,
It has been applied to various fields such as printers and labels, and its needs are expanding. However, these thermal recording materials are
In the field of labels, slips, word processor paper, plotter paper, etc., they have the drawback that fog is caused by the adhesion of solvents etc. and that the color developing body undergoes discoloration due to oils and fats and chemicals. , The commercial value is significantly impaired.

The present inventors have prepared a colorless or light-colored electron-donating dye precursor and an electron-accepting compound, respectively.
Focusing on its oil solubility, solubility in water, partition coefficient, pKa, polarity of substituents, position of substituents, etc., as a result of various studies on recording material and recording material, it was found that fog is less likely to occur due to solvent etc. In this case, it has been found that the color-developing material is likely to be discolored by oils and fats or chemicals, while the color-developing material is less likely to be discolored by oils or fats or chemicals, the fog tends to occur due to a solvent or the like. .

[0005]

Accordingly, the present inventors have found that
As a result of diligent research to solve such a drawback, it was found that the isocyanate compound and the amino compound react with each other when heated to form a urea compound, and the generated urea compound acts as an electron-accepting compound to increase the sensitivity. The present invention has been completed. Therefore, an object of the present invention is to provide a heat-sensitive recording material which is excellent in raw storability and stability of a color image and has high sensitivity and excellent printing quality.

[0006]

The above objects of the present invention are as follows.
This is achieved by a heat-sensitive recording material comprising a support and a heat-sensitive color-forming layer containing a colorless or light-colored electron-donating dye precursor, an isocyanate compound and an amino compound.

JP-A-60-184879 and JP-A-60-210491 disclose heat-sensitive recording materials containing blocked phenol as an electron-accepting compound, and an isocyanate is also used. The isocyanate compound in these cases merely plays a role of blocking the phenol compound, and since the above-mentioned isocyanate is generated as a result of decomposition by a thermal reaction, a large amount of heat is required to generate it. Therefore, the present invention is significantly different from the present invention in that the thermal sensitivity is deteriorated contrary to the case of the present invention. The isocyanate compound used in the present invention can be appropriately selected and used from colorless or pale-colored isocyanate compounds which are solid at room temperature, and particularly, aromatic isocyanate having two or more -NCO groups. Preference is given to using compounds.

Representative isocyanate compounds which can be used in the present invention include, for example, 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, 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'-di Isocyanate, diphenylmethane-4,4'-diisocyanate, benzophenone-3,3'-diisocyanate, fluorene-2,
7-diisocyanate, anthraquinone-2,6-diisocyanate, 9-ethylcarbazole-3,6-diisocyanate, pyrene-3,8-diisocyanate, naphthalene-1,3,7-triisocyanate , Biphenyl-2,4,4'-triisocyanate, 4,4 ',
4 ″ -triisocyanate-2,5-dimethoxytriphenylamine, p-dimethylaminophenylisocyanate, tris (4-phenylisocyanate) thiophosphate and the like. In the present invention, among these, 4, 4 ', 4 "-triisocyanate-2,5
-Dimethoxytriphenylamine is preferred. Further, these isocyanate compounds may be used alone or in combination of two or more kinds. In the present invention, an isocyanate compound is used as a colorless or light-colored electron donor dye precursor of 50
It is preferable to use ~ 800 wt%, especially 100 ~
It is preferable to use 500% by weight.

The amino compound used in the present invention can be appropriately selected from compounds having at least one NH ₂ group in one molecule, but an amino compound having two or more NH ₂ groups is used. It is preferable to use it in combination with an aromatic isocyanate compound having two or more NCO groups. In the present invention, it is particularly preferable to use an amino compound represented by the following chemical formula 4.

[Chemical 4]

In the above formula, X is a direct bond, --CO--, --SO.
₂ -, - CONH-, or represents -SO ₂ NH-,
R ₁ , R ₂ and R ₃ are hydrogen atom, alkyl group, aryl group, alkoxy group, aryloxy group, sulfonyloxy group, oxycarbonyl group, carbamoyl group, sulfamoyl group, oxysulfonyl group, acyl group, sulfonyl group, halogen atom, a nitro group, a cyano group, hydroxy _{group, -CONH 2, -SO 2 NH 2} , -CONHN
H _2, represents a -SO ₂ NHNH ₂ or the following formula 5.

[Chemical 5]

In the above formula, Y represents a divalent group, and R ₄ and R
₅ is a hydrogen atom, an alkyl group, an aryl group, an alkoxy group, an acyl group, a sulfonyl group, a halogen atom, a nitro group or a cyano group, and X ₂ is a direct bond, -CO-, -SO.
₂ -, - CONH- or an -SO ₂ NH-. These substituents may further have a substituent, and
R ₁ and R ₂ , and R ₄ and R ₅ may be linked to each other to form a ring.

In the heat-sensitive recording material of the present invention, as described above, it is particularly preferable to use a compound having two or more amino groups as the amino compound, but among the compounds having two or more amino groups, Those represented by Chemical formula 6 are particularly preferable.

[Chemical 6]

In the above formula, Z represents a divalent group, R ₆ ,
R ₇ , R ₈ and R ₉ each represent a hydrogen atom, an alkyl group, an aryl group, an alkoxy group, an acyl group, a sulfonyl group, a halogen atom, a nitro group or a cyano group. Examples of Z include a single bond, -O-, -CO-, -S-, -SO.
_{-, - SO 2 -, -} CH 2 -, the other SO ₂ NH-, can be mentioned various groups represented by the following chemical formula 7.

[Chemical 7]

Representative amino compounds that can be used in the present invention include, for example, 4-biphenyloxyaniline, 3-diphenylmethyloxyaniline, 4-phenoxyacetylaniline, 4-phenylacetylaniline and 4-myristoylaniline. , 3-phenylsulfonylaniline, 3-biphenylsulfonylaniline, 3
-Dodecylsulfonylaniline, 3-biphenylsulfonyloxyaniline, 3-β-naphthalenesulfonyloxyaniline, 4-benzyloxycarbonylaniline, 3-dodecyloxycarbonylaniline, 4-N-
Phenylcarbamoylaniline, 4-N-dodecylcarbamoylaniline, 4-N-benzylcarbamoylaniline, 4-N-phenylsulfamoylaniline, 4-
N-dodecylsulfamoylaniline, 4-N-benzylsulfamoylaniline, 4-biphenyloxysulfonylaniline, 3-β-naphthyloxysulfonylaniline, 4-benzyloxybenzamide, 4-dodecyloxybenzamide, 4-benzyloxy Carbonylbenzamide, 3-benzyloxycarbonylbenzamide, 2-benzyloxybenzamide, 3,5-dicumylsalicylamide, 3,5-di-t-butylsalicylamide, 4-benzyloxybenzenesulfonamide,
4-benzyloxycarbonylbenzenesulfonamide, 4-benzyloxybenzohydrazide, β-naphthohydrazide, 1-p-toluenesulfonylhydrazine,
1- (4-benzyloxyvansensulfonyl) hydrazine;

3,3'-dimethyl-4,4'-diaminodiphenyl, 2,2'5,5'-tetrachloro-4,
4'-diaminodiphenyl, 4,4'-methylenebis (2-chloroaniline), 3,4'-diaminodiphenyl ether, 4,4'-diaminodiphenyl ether,
4,4'-diaminodiphenyl sulfone, 2,2-bis [4- (4-aminophenoxy) phenyl] propane,
Bis [4- (4-aminophenoxy) phenyl] sulfone, bis [4- (3-aminophenoxy) phenyl] sulfone, 4,4′-bis (4-aminophenoxy) biphenyl, bis [4- (4-amino) Phenoxy) phenyl] ether, 2,2-bis [4- (4-aminophenoxy) phenyl] hexafluoropropane, 1,3-bis (4-aminophenoxy) phenoxy) benzene,
1,4-bis (4-aminophenoxy) benzene, 4,
4'-diaminodiphenyl sulfide, 3,3'-diaminodiphenyl sulfone, 4,4'-diaminobenzanilide, 9,10-bis (4-aminophenyl) anthracene, 9,9-bis (4-aminophenyl) fluorene , O-toluidine sulfone, 2,2-bis [4- (4
-Aminophenylmethyl) phenyl] hexafluoropropane, 2,2-bis [4- (4-aminobenzoyl)
Phenyl] hexafluoropropane, 2,2-bis [4
-(N-4-aminophenylcarbamoyl) phenyl]
Hexafluoropropane, 2,2-bis [4- (4-aminophenoxy) phenyl] propane, 2,2-bis [4- (4-aminophenoxymethyl) phenyl] propane, 2,2-bis [4- ( 4-aminobenzoyl) phenyl] propane, 2,2-bis [4- (N-4-aminophenylcarbamoyl) phenyl] propane, 2,2
-Bis [4-β- (4-aminophenoxy) ethoxyphenyl] propane and the like. These can be used alone,
You may use 2 or more types together.

The amount of the amino compound added is preferably 5 to 1,000% by weight of the isocyanate compound,
Particularly, it is preferably in the range of 10 to 500% by weight. The dispersed particle size of the isocyanate compound or amino compound after atomization by a sand mill or the like is preferably 3 μm or less, and particularly preferably 2 μm or less, from the viewpoint of improving the color development sensitivity. Also,
The isocyanate compound may be dispersed simultaneously with the amino compound and / or the alcoholic compound.

In the present invention, the well-known phenol derivative, phenol resin, novolac resin, metal-treated novolac resin, metal complex, salicylic acid derivative, metal salt of aromatic carboxylic acid, together with an isocyanate compound and an amino compound, An electron-accepting compound such as acid clay or bentonite may be used in combination. Examples of these are JP-B-40-9309, JP-B-45-14039, JP-A-52-140483, JP-A-48-51510 and JP-A-5-51038.
7-210886, 58-87089, 59-
No. 11286, No. 60-176795, No. 61-95
No. 988, etc.

Specific examples of these include 4-tert-butylphenol, 4-phenylphenol, 2,2'-dihydroxybiphenyl, 2,2-bis (4-hydroxyphenyl) propane (bisphenol A), 4, 4'-sec-butylidene diphenol,
4,4'-cyclohexylidene diphenol, bis (3
-Aryl-4-hydroxyphenyl) sulfone, 4-
Hydroxyphenyl-3 ', 4'-dimethylphenyl sulfone, 4- (4-isopropoxyphenylsulfonyl) phenol, 4,4'-dihydroxydiphenyl sulfide, 1,4-bis- (4'-hydroxycumyl) benzene, 1,3-bis- (4'-hydroxycumyl) benzene, 4,4'-thiobis (6-tert-butyl-3-methylphenol), 1,1,3-tris (2-methyl-4-hydroxy) -5-tert-butylphenyl) butane, 4,4'-butylidene-bis- (3
-Methyl-6-tert-butylphenol), 4,
4'-dihydroxydiphenyl sulfone, 4-hydroxybenzoic acid benzyl ester;

3,5-di-tert-butylsalicylic acid, 3-phenyl-5- (α, α-dimethylbenzyl)
Salicylic acid, 3-cumyl-5-t-octylsalicylic acid, 3,5-di-t-butylsalicylic acid, 3-phenyl-5-t-octylsalicylic acid, 3-methyl-5-α-
Methylbenzylsalicylic acid, 3-methyl-5-cumylsalicylic acid, 3,5-di-t-octylsalicylic acid, 3,
5-bis (α-methylbenzyl) salicylic acid, 3-cumyl-5-phenylsalicylic acid, 5-n-octadecylsalicylic acid, 4-pentadecylsalicylic acid, 3,5-bis (α, α-dimethylbenzyl) salicylic acid, 3, 5-bis-t-octylsalicylic acid, 4-β-dodecyloxyethoxysalicylic acid, 4-methoxy-6-dodecyloxysalicylic acid, 4-β-phenoxyethoxysalicylic acid, 4-β-p-ethylphenoxyethoxysalicylic acid, 4-β There are -p-methoxyphenoxyethoxysalicylic acid and the like and metal salts thereof.

In the present invention, the above electron-accepting compound is preferably mixed with the isocyanate compound in a proportion of 0 to 200% by weight. Moreover, you may use together 2 or more types of the said electron-accepting compound. Examples of colorless or light-colored electron-donating dye precursors used in the present invention include triphenylmethanephthalide compounds, fluorane compounds, phenothiazine compounds, indolylphthalide compounds, leukoauramine compounds, rhodamine. There are various compounds such as a lactam compound, a triphenylmethane compound, a triazene compound, a spiropyran compound, and a fluorene compound, and a fluorane compound represented by the following chemical formula 8 is particularly preferable.

[Chemical 8] In the formula, R ₁ and R ₂ represent an alkyl group which may be substituted with either an alkoxy group or a tetrahydrofurfuryl group, and R ₁ and R ₂ may be the same or different; R ₃ , R ₄ and R ₅ represent a hydrogen atom, a halogen atom or an alkyl group, and R ₃ , R ₄ and R ₅ may be the same or different.

Specific examples of the phthalides include US Reissue Patent Specification No. 23,024 and US Patent Specification No. 3,491,1.
No. 11, No. 3,491, 112, No. 3,491,
116 and 3,509,174, specific examples of fluoranes are US Pat. No. 3,624,107,
No. 3,627,787, No. 3,641,011
No. 3,462,828, No. 3,681,39
No. 0, No. 3,920,510, No. 3,959,5
71, specific examples of spiro dipyrans are US Pat. No. 3,971,808, and pyridine compounds and pyrazine compounds are US Pat. Nos. 3,775,424 and 3,853,869; No. 4,246,318 and specific examples of fluorene compounds are described in JP-A-63-94878.

Of these, 2-arylamino-3-, halogen- or alkyl-6-substituted aminofluoranes which develop black color are particularly effective, and specific examples thereof include 2-anilino-3-methyl-6. -Diethylaminofluorane, 2-anilino-3-methyl-6-N-cyclohexyl-N-methylaminofluorane, 2-p-chloroanilino-3-methyl-6-dibutylaminofluorane,
2-anilino-3-chloro-6-diethylaminofluorane, 2-anilino-3-methyl-6-N-ethyl-N
-Isoamylaminofluorane, 2-anilino-3-methyl-6-N-ethyl-N-dodecylaminofluorane, 2-anilino-3-pentadecyl-6-diethylaminofluorane, 2-anilino-3-ethyl-6 -Dibutylaminofluorane, 2-o-toluidino-3-methyl-6-diisopropylaminofluorane, 2-anilino-3-methyl-6-N-isobutyl-N-ethylaminofluorane, 2-anilino-3- Methyl-6-N-ethyl-N-tetrahydrofurfurylaminofluorane,
2-anilino-3-chloro-6-N-ethyl-N-isoamylaminofluorane, 2-anilino-3-methyl-
6-N-methyl-N-γ-ethoxypropylaminofluorane, 2-anilino-3-methyl-6-N-ethyl-
N-γ-ethoxypropylaminofluorane, 2-anilino-3-methyl-6-N-ethyl-N-γ-propoxypropylaminofluorane, 2-anilino-3-methyl-6-N-methyl-N- Examples include propylaminofluorane.

Examples of sensitizers that can be used in the present invention include JP-A Nos. 58-57989 and 58-870.
The compounds disclosed in JP-A Nos. 94 and 63-39375 and the like can be mentioned. Specific examples thereof include aromatic ethers (particularly preferably benzyl ethers and di (substituted phenoxy) alkanes), aromatic esters, aliphatic amides, aromatic amides, ureas and the like.

Next, a method for producing a typical thermosensitive coloring layer of the present invention will be described. Colorless or light-colored electron-donating dye precursor,
Isocyanate compounds, amino compounds and sensitizers, along with a water-soluble polymer aqueous solution such as polyvinyl alcohol,
It is dispersed to a few microns or less using a ball mill or sand mill. The sensitizer may be added to the colorless or light-colored electron-donating dye precursor, the isocyanate compound, the amino compound, or both, and may be dispersed at the same time.

These dispersions are mixed after dispersion and, if necessary, pigments, surfactants, binders, metal soaps, waxes, antioxidants, ultraviolet absorbers and the like are added to prepare a heat-sensitive coating liquid. The resulting heat-sensitive coating liquid is applied and dried on a support such as high-quality paper, high-quality paper having an undercoat layer, synthetic paper, plastic film, etc., and then a calendering process is applied to impart smoothness to the target surface for desired heat-sensitive recording. Get the material.

In this case, it is particularly preferable in terms of dot reproducibility to use a support having a smoothness defined by JIS-8119 of 500 seconds or more, particularly 800 seconds or more. In order to obtain a support having a smoothness of 500 seconds or more, (1) a highly smooth one such as synthetic paper or a plastic film is used, and (2) an undercoat layer containing a pigment as a main component on the support. And (3) using a super calender or the like to increase the smoothness of the support.

The binder is preferably a compound which dissolves in water at 25 ° C. in an amount of 5% by weight or more.
Polyvinyl alcohol (including modified polyvinyl alcohol such as carboxy-modified, itaconic acid-modified, maleic acid-modified, and silica-modified), methyl cellulose, carboxymethyl cellulose, starches (including modified starch), gelatin, gum arabic, casein, styrene-maleic anhydride Examples thereof include acid copolymer hydrolysates, polyacrylamides, and saponified products of vinyl acetate-polyacrylic acid copolymers.

These binders are used not only at the time of dispersion but also for the purpose of improving the coating film strength. For the purpose of improving the coating film strength, a styrene / butadiene copolymer and a vinyl acetate copolymer are used. It is also possible to use a latex binder of synthetic polymer such as acrylonitrile / butadiene copolymer, methyl acrylate / butadiene copolymer, or polyvinylidene chloride. Moreover, you may add a suitable crosslinking agent according to the kind of these binders.

Examples of pigments include calcium carbonate, barium sulfate, lithopone, wax, kaolin, silica and amorphous silica. As the metal soap, higher fatty acid metal salts are used, such as zinc stearate, calcium stearate, and aluminum stearate. Further, if necessary, a surfactant, an antistatic agent, an ultraviolet absorber,
You may add a defoaming agent, a conductive agent, a fluorescent dye, a coloring dye, etc.

The heat-sensitive recording material applied is dried, treated with a calender and the like and then used. Further, a protective layer may be provided on the thermosensitive coloring layer, if necessary. The protective layer can be appropriately selected and used from known materials as a protective layer for heat-sensitive recording materials. Further, if necessary, a back coat layer may be provided on the surface of the support of the heat-sensitive recording material opposite to the heat-sensitive color developing layer. As the back coat layer, any one known as a back coat layer of a thermal recording material can be used.

[0031]

As described in detail above, in the heat-sensitive recording material of the present invention, the isocyanate compound and the amino compound react with each other during heating to produce an electron-accepting compound, and the resulting electron-accepting compound has a sufficiently large molecular weight. Therefore, recrystallization or
Since it is not dissolved by a solvent, the image storability is very good and the raw storability is also very good. Further, the generated electron-accepting compound is a urea compound, and since the reaction with the electron-donating dye precursor is extremely quick, not only the thermal sensitivity but also the color density is high, and the electron-accepting property in the unheated part is high. Since there is no compound, there is also an advantage that fog due to a solvent does not occur.

[0032]

The present invention will be described in more detail with reference to the following examples, but the present invention is not limited thereto.

Example 1. 2-anilino-3-methyl-6-N-methyl-Nn-propylaminofluorane as a colorless or light-colored electron-donating dye precursor, and 4,4 ', 4 "-triisocyanate as an isocyanate compound 20 g each of 2,2,5-dimethoxytriphenylamine, 3,3′-diaminodiphenyl sulfone as an amino compound, and β-naphthylbenzyl ether as a sensitizer
100 g of 5% polyvinyl alcohol (PVA-1
(05: manufactured by Kuraray Co., Ltd.) and dispersed with a ball mill for 24 hours to obtain each dispersion having an average particle diameter of 1.5 μm or less. On the other hand, 80 g of calcium carbonate was dispersed in 160 g of a 0.5% sodium hexametaphosphate solution with a homogenizer to obtain a pigment dispersion liquid.

5 g of the colorless or light-colored electron-donating dye precursor dispersion, 5 g of the isocyanate compound dispersion, and 5 g of the amino compound dispersion were prepared from the dispersions prepared as described above.
A β-naphthylbenzyl ether dispersion liquid (10 g) and a calcium carbonate dispersion liquid (5 g) were mixed, and 21% zinc stearate emulsion (3 g) was further added to obtain a coating liquid for a thermosensitive color developing layer. This thermosensitive coloring layer coating solution was applied to a basis weight of 50 g / m ²
Was coated on a wood free paper using a wire bar so that the dry weight of the coating layer was 5 g / m ^2, and dried at 50 ° C. for 1 minute to obtain a heat sensitive recording paper.

Next, the obtained thermal recording paper was surface-treated with a calender, and the smoothness was 300 ± 5 as Beck's smoothness.
The heat-sensitive recording material was obtained by adjusting the time to 0 seconds. The thermal recording paper thus obtained was evaluated as follows. (1) Color density The color density when printed with a printing energy of 30 mJ / mm ² was measured with a Macbeth densitometer using a printing tester manufactured by Kyocera Corporation. The higher this value, the higher the sensitivity of the recording paper. (2) Chemical resistance test of thermosensitive recording paper Using a printing tester manufactured by Kyocera Co., Ltd., a portion printed and printed at a printing energy of 30 mJ / mm ² is impregnated with ethanol or a plasticizer (dioctyl phthalate). Each of them was overlaid on a filter paper and evaluated for the degree of fog and decolorization (discoloration) of the colored portion after 48 hours. The above results are shown in Table 1.

Example 2. 3,3′-used in Example 1
A thermosensitive recording material was obtained in the same manner as in Example 1 except that 4,4′-diaminodiphenyl sulfide was used in place of diaminodiphenyl sulfone, and the color density was measured in the same manner as in Example 1 and the chemical resistance was measured. A sex test was conducted. The results are as shown in Table 1.

Example 3. 3,3′-used in Example 1
A thermosensitive recording material was obtained in the same manner as in Example 1 except that 1,3-bis (4-aminophenoxy) benzene was used instead of diaminodiphenylsulfone, and the color density was measured in the same manner as in Example 1. At the same time, a chemical resistance test was conducted. The results are as shown in Table 1.

Example 4. 3,3′-used in Example 1
A thermosensitive recording material was obtained in the same manner as in Example 1 except that 1,4-bis (4-aminophenoxy) benzene was used in place of diaminodiphenylsulfone, and the color density was measured in the same manner as in Example 1. At the same time, a chemical resistance test was conducted. The results are as shown in Table 1.

Example 5. 3,3′-used in Example 1
A thermosensitive recording material was obtained in the same manner as in Example 1 except that 4,4′-diaminodiphenyl ether was used in place of diaminodiphenyl sulfone, and the color density was measured in the same manner as in Example 1 and the chemical resistance was also obtained. I did a test.
The results are as shown in Table 1.

Example 6. 3,3′-used in Example 1
Instead of diaminodiphenyl sulfone, bis [4-
A thermosensitive recording material was obtained in the same manner as in Example 1 except that (4-aminophenoxy) phenyl] sulfone was used, and the color density was measured and the chemical resistance test was conducted in the same manner as in Example 1. . The results are as shown in Table 1.

Example 7. 3,3′-used in Example 1
Instead of diaminodiphenyl sulfone, bis [4-
A thermosensitive recording material was obtained in the same manner as in Example 1 except that (3-aminophenoxy) phenyl] sulfone was used, and the color density was measured and the chemical resistance test was performed in the same manner as in Example 1. . The results are as shown in Table 1.

Example 8. 3,3′-used in Example 1
A thermosensitive recording material was obtained in the same manner as in Example 1 except that 4,4′-diaminobenzanilide was used instead of diaminodiphenyl sulfone, and the color density was measured in the same manner as in Example 1 and A chemical test was conducted.
The results are as shown in Table 1.

Example 9. 3,3′-used in Example 1
Instead of diaminodiphenyl sulfone, bis [4-
A thermosensitive recording material was obtained in the same manner as in Example 1 except that (4-aminophenoxy) phenyl] ether was used, and the color density was measured and the chemical resistance test was conducted in the same manner as in Example 1. . The results are as shown in Table 1.

Example 10. 3,3 ′ used in Example 1
A thermosensitive recording material was obtained in the same manner as in Example 1 except that 2,2-bis [4- (4-aminophenoxy) phenyl] hexafluoropropane was used in place of diaminodiphenylsulfone. The color density was measured and a chemical resistance test was conducted in exactly the same manner. The results are as shown in Table 1.

Example 11. 3,3 ′ used in Example 1
A thermosensitive recording material was obtained in the same manner as in Example 1 except that 1-p-toluenesulfonylhydrazine was used instead of diaminodiphenylsulfone, and the color density was measured in the same manner as in Example 1 and A chemical test was conducted. The results are as shown in Table 1.

Example 12. 3,3 ′ used in Example 1
A thermosensitive recording material was obtained in the same manner as in Example 1 except that m-toluenesulfonamide was used in place of diaminodiphenylsulfone, and the color density was measured in the same manner as in Example 1 and the chemical resistance was measured. I did a test. The results are as shown in Table 1.

Comparative Example 1 A heat-sensitive recording material was prepared and carried out in the same manner as in Example 1 except that the heat-sensitive coating liquid was prepared without adding 3,3'-diaminodiphenyl sulfone used in Example 1. In the same manner as in Example 1, the color density was measured and a chemical resistance test was conducted. The results are as shown in Table 1.

Comparative Examples 2-5. 4, used in Example 1
Instead of using 5 g of 4 ', 4 "-triisocyanate-2,5-dimethoxytriphenylamine dispersion and 5 g of 3,3'-diaminodiphenyl sulfone dispersion, respectively, bisphenol A, 4- (4-isopropoxy) was used. Phenylsulfonyl) phenol, 4,4′-butylidene-bis- (3-methyl-6-tert-butylphenol), 1,4-bis- (4′-hydroxycumyl) benzene dispersion was used except that 10 g was used. A heat-sensitive recording material was prepared in exactly the same manner as in Example 1, the color density was measured and the chemical resistance test was conducted in exactly the same manner as in Example 1. The results are shown in Table 1.

Comparative Example 6. 4,4 ′ used in Example 1,
Instead of using 5 g of 4 "-triisocyanate-2,5-dimethoxytriphenylamine dispersion and 5 g of 3,3'-diaminodiphenyl sulfone dispersion, 4,4 ', 4" -tri was previously prepared in a toluene solution. Isocyanato-2,5-dimethoxytriphenylamine and equimolar 3,3'-diaminodiphenylsulfone were reacted for 2 hours at 50 ° C, and 20 g of the compound was reacted with 100 g of 5% polyvinyl alcohol (PVA-105) aqueous solution. A thermosensitive recording material was prepared in exactly the same manner as in Example 1 except that 10 g of the dispersion liquid dispersed in a ball mill was used all day and night, and the color density was measured and the chemical resistance test was conducted in exactly the same manner as in Example 1. It was The results are as shown in Table 1.

[0050]

[Table 1] From the results shown in Table 1, it is demonstrated that the recording material of the present invention has a sufficient color density, and does not cause fog color development or decolorization of the color development part due to chemicals, and has extremely excellent performance. It was

Claims (5)

[Claims] 1. A colorless or light-colored electron-donating dye precursor,
A heat-sensitive recording material comprising a support and a heat-sensitive color-forming layer containing an isocyanate compound and an amino compound. 2. The heat-sensitive recording material according to claim 1, wherein the isocyanate compound is an aromatic isocyanate compound having two or more —NCO groups. 3. The heat-sensitive recording material according to claim 1, wherein the amino compound is a compound represented by the following chemical formula 1. [Chemical 1] In the above formulas, X is a direct _{bond, -CO -, - SO 2 -} , - CO
NH- or an _{-SO 2 NH-, R 1, R} 2 and R
₃ is a hydrogen atom, alkyl group, aryl group, alkoxy group, aryloxy group, sulfonyloxy group, oxycarbonyl group, carbamoyl group, sulfamoyl group, oxysulfonyl group, acyl group, sulfonyl group, halogen atom, nitro group, cyano group, respectively. Group, hydroxy group, -CONH
_{2, -SO 2 NH 2, -CONHNH} 2, -SO 2 NH
Represents NH ₂ or the following chemical formula ₂ . [Chemical 2] In the above formula, Y represents a divalent group, R ₄ and R ₅ are each a hydrogen atom, an alkyl group, an aryl group, an alkoxy group, an acyl group, a sulfonyl group, a halogen atom, a nitro group or a cyano group, and X ₂ is a direct _{bond, -CO -, - SO 2 -} , - CO
NH- or an -SO ₂ NH-. These substituents may further have a substituent, and R ₁ and R ₂ and R ₄ and R ₅ may be linked to each other to form a ring. 4. The heat-sensitive recording material according to claim 1, wherein the amino compound has two or more —NH ₂ groups. 5. The electron donating dye precursor is a fluorane compound represented by the following chemical formula 3.
To the thermosensitive recording material according to any one of 4 to 4; In the formula, R ₁ and R ₂ represent an alkyl group which may be substituted with either an alkoxy group or a tetrahydrofurfuryl group, and R ₁ and R ₂ may be the same or different; R ₃ , R ₄ and R ₅ represent a hydrogen atom, a halogen atom or an alkyl group, and R ₃ , R ₄ and R ₅ may be the same or different.