JP2002283725A - Heat-sensitive recording material - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a heat-sensitive recording material which is excellent in image preservability, especially, image light fastness in the heat-sensitive recording material in which a heat-sensitive recording layer containing a diazonium salt compound and coupler compound is provided. SOLUTION: This heat-sensitive recording material is provided with the heat sensitive recording layer which contains at least the diazonium salt compound and the coupler compound causing a coupling reaction with the diazonium salt compound on a supporting body. In this material, the heat-sensitive layer contains compounds which are represented by a formula 1, wherein R1 , R2 and R3 are each independently an alkyl group, an aryl group, and an acyl group which may have substituents, and the R1 and R2 , R2 and R3 , and R3 and R1 each may form a ring. Furthermore, in the formula 1, it is desirable that at least one of the R1 , R2 and R3 is the aryl group.

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 containing a diazonium salt compound and a coupler compound as a color-forming component and having excellent image preservability (light fastness).

[0002]

2. Description of the Related Art A diazonium salt compound is a compound having a very high chemical activity. It reacts with a compound called a coupler such as a phenol derivative or a compound having an active methylene group to easily form an azo dye, Also decomposes by light irradiation and loses its activity. For this reason, diazonium salt compounds have long been used as optical recording materials typified by diazocopy ("Photographic Engineering Fundamentals-Non-Silver Salt Photography-" edited by The Photographic Society of Japan, Corona (1982) 89-117; 182-201).

Further, by utilizing the property of decomposing by light and losing activity, it has recently been applied to recording materials which require fixing of an image. As a typical example, a diazonium salt compound and a coupler compound are used to form an image signal. A heat-fixable thermosensitive recording material has been proposed in which an image is formed by heating, reacting, and then irradiating with light to fix the image (Koji Sato et al., Journal of the Institute of Image Electronics Engineers, Vol. 11, No. 4, (1982) 290
296 pages).

However, in these recording materials using a diazonium salt compound as a coloring element, the activity of the diazonium salt compound is extremely high, and even in a dark place, the diazonium salt compound gradually decomposes and loses reactivity. Therefore, there was a disadvantage that the shelf life as a recording material was short. As one of means for improving this drawback, there is a method of encapsulating a diazonium salt compound in microcapsules. According to this method, the diazonium salt compound is
It can be isolated from substances that promote decomposition, such as water and base, and can dramatically improve shelf life as a recording material (Masamasa Usami et al. Journal of the Institute of Electrophotographic Studies Vol. 26, No. 2) No. (1987) 115-1
25).

On the other hand, as the diazonium salt compound used as the heat-sensitive recording material, 4-disubstituted amino-2
-Alkoxybenzenediazonium salt shows particularly excellent performance (JP-A-4-59288), and when the diazonium salt compound is subjected to a coupling reaction with a barbituric acid derivative, a red dye having an extremely good hue is obtained. Is known (Japanese Patent Laid-Open No. 4-197778).
However, when these are used as a coloring element of a thermosensitive recording material, there is a problem that the storage stability (light resistance) of a coloring image is not sufficient.

In order to solve the above problem, Japanese Patent Laid-Open Publication No. 7-125
In Japanese Patent No. 446, when a diazonium salt compound having a specific substituent and a barbituric acid derivative having a specific substituent are used as a coupler compound, the thermosensitive recording material exhibits excellent performance in terms of image storability. It is disclosed. Also, in JP-A-9-156229, a diazonium salt compound having a specific substituent,
It is disclosed that when a 4-hydroxycoumarin derivative is used as a coupler compound, it exhibits excellent image storability (light fastness).

However, in order to further improve image storability (light fastness), it has been desired to obtain a discoloration inhibitor suitable for a heat-sensitive recording material using a diazonium salt compound and a coupler compound as a color-forming element.

[0008]

SUMMARY OF THE INVENTION An object of the present invention is to solve the above-mentioned conventional problems and achieve the following objects. That is, an object of the present invention is to provide a heat-sensitive recording material provided with a heat-sensitive recording layer containing a diazonium salt compound and a coupler compound, which is excellent in image storability, particularly, image light fastness.

[0009]

Means for solving the above problems are as follows. <1> A thermosensitive recording material comprising a support having thereon a thermosensitive recording layer containing at least a diazonium salt compound and a coupler compound capable of performing a coupling reaction with the diazonium salt compound, wherein the thermosensitive recording layer has the following general formula ( A heat-sensitive recording material comprising the compound represented by I).

[0010]

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In the general formula (I), R ₁ , R ₂ and R ₃ each independently represent an alkyl group, an aryl group or an acyl group. R ₁ , R ₂ and R ₃ may further have a substituent. R ₁ and R ₂ , R ₂ and R ₃ , and R ₃ and R ₁ may form a ring with each other.

<2> In the general formula (I), R ₁ , R ₂
And the thermal recording material according to <1>, wherein at least one of R ₃ and R ₃ is an aryl group.

<3> The diazonium salt compound contains a 4-disubstituted amino-2-alkoxybenzenediazonium salt represented by the following general formula (II), and the coupler compound is represented by the following general formula (III) <1> or <2>, which comprises at least one of a compound represented by the following general formula (IV) and a compound represented by the following general formula (IV).

[0014]

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In the general formula (II), R ₄ , R ₅ and R ₆ each independently represent an alkyl group, an aralkyl group or an aryl group. R ₄ and R ₅ may form a ring together with the nitrogen atom. X represents an acid anion.

[0016]

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In the general formula (III), Y ¹ and Y ²
Are each independently a hydrogen atom, an alkyl group having 1 to 18 carbon atoms, an aralkyl group having 7 to 21 carbon atoms, or a 6 to 2 carbon atoms.
Represents an aryl group of 0.

[0018]

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In the general formula (IV), R ₇ , R ₈ , R
₉ and R ₁₀ are each independently a hydrogen atom, an alkyl group, an aryl group, an aralkyl group, an alkyloxy group, an aryloxy group, an alkylthio group, an arylthio group, an acyl group, an alkoxycarbonyl group, an acyloxy group, a carbamoyl group, a sulfamoyl group. Represents a group, a halogen atom, a cyano group or a nitro group. R ₇ , R ₈ , R ₉ , and R ₁₀ may be the same or different. R ₇ and R ₈ , R ₈ and R ₉ , and R ₉ and R ₁₀ may combine with each other to form a ring.

[0020]

BEST MODE FOR CARRYING OUT THE INVENTION (Thermal Recording Material) The thermal recording material of the present invention will be described below. The heat-sensitive recording material of the present invention is a heat-sensitive recording material provided on a support, at least a diazonium salt compound, and a heat-sensitive recording layer containing a coupler compound that undergoes a coupling reaction with the diazonium salt compound. And a compound represented by the general formula (I). First, the compound represented by formula (I) will be described.

<Compound Represented by General Formula (I)> The heat-sensitive recording material of the present invention comprises a heat-sensitive recording layer provided on a support, and the heat-sensitive recording layer comprises a diazonium salt compound and the diazonium salt compound. And a compound represented by the following general formula (I):
Contains phosphite compounds. The phosphite compound represented by the following general formula (I) may form a dimer and be contained in the thermosensitive recording layer. By including the phosphite compound in the heat-sensitive recording layer of the heat-sensitive recording material of the present invention, a heat-sensitive recording material having excellent storage stability of color images, particularly excellent light resistance can be obtained.

[0022]

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In the general formula (I), R ₁ , R ₂ and R ₃ each independently represent an alkyl group, an aryl group or an acyl group. R ₁ , R ₂ and R ₃ may further have a substituent. R ₁ and R ₂ , R ₂ and R ₃ , and R ₃ and R ₁ may form a ring with each other. In addition, the general formula (I)
In, it is preferable that at least one of R ₁ , R ₂ and R ₃ is an aryl group.

In the general formula (I), the substituent represented by R ₁ , R ₂ and R ₃ preferably has 6 to 100 carbon atoms, more preferably 8 to 50 carbon atoms.

The following are specific examples of the phosphite compound represented by the general formula (I), but the phosphite compound of the present invention is not limited thereto.

[0026]

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[0027]

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[0028]

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The phosphite compound represented by the general formula (I) contained in the heat-sensitive recording material of the present invention includes:
Among the specific examples, ADK STAB 1500, ADK STAB 329K, ADK STAB 1178 (SL-TN
P) and ADK STAB 2112 are preferred, and ADK STAB 1500 and ADK STAB 1178 (SL-TNP)
More preferred.

In the heat-sensitive recording material of the present invention, the amount of the phosphite compound represented by the general formula (I) is 0.5 to 100 with respect to the diazonium salt compound.
A mass part is preferable and 2 to 20 mass parts is more preferable.
If the amount is less than 0.5 part by mass, the effect on the light fastness of the recorded image is insufficient, and if the amount is more than 100 parts by mass, there is almost no difference in effect, so that it is preferably within the above range. The phosphite-based compound represented by the general formula (I) may be used alone or in combination of two or more in the heat-sensitive recording layer of the heat-sensitive recording material of the present invention.

The phosphite-based compound represented by the general formula (I) is used together with a diazonium salt compound described below,
It can be used in the form contained in the microcapsules described below, can also be used in the form of a solid dispersion together with a coupler compound or an organic basic substance described later, or can be used in the form of an emulsion together with a suitable emulsifying aid. It can also be used in an embodiment. Further, the above-described embodiments can be used in combination.

Incidentally, other known antioxidants (anti-fading agents) may be contained together with the phosphite compound represented by the above general formula (I). The antioxidants are structurally classified as anilines, alkoxybenzenes, hindered phenols, hindered amines, hydroquinone derivatives, phosphorus compounds, sulfur compounds and have different structures. The antioxidant is described in JP-A-9-156229 and the like.

Next, in the present invention, the diazonium salt compound and the coupler compound which are the coloring components contained in the heat-sensitive recording layer will be described.

<Diazonium Salt Compound and Coupler Compound> The diazonium salt compound is a compound represented by the following formula. These compounds control the maximum absorption wavelength depending on the position and type of the substituent in the Ar portion. Can be done.

Ar—N ₂ ⁺ X ⁻ (wherein, Ar represents an aromatic moiety and X ⁻ represents an acid anion)

The diazonium salt compound represented by the above formula is a compound which undergoes a coupling reaction with a coupler compound by heating to form a color and is decomposed by light.
The maximum absorption wavelength of the diazonium salt can be controlled by the position and type of the substituent in the Ar portion.

The maximum absorption wavelength λ _max of the diazonium salt compound contained in the heat-sensitive recording layer of the heat-sensitive recording material of the present invention is:
It is preferably 400 nm or less from the viewpoint of the effect.
More preferably, it is 40 to 380 nm. The diazonium salt compound has a λ at a longer wavelength side than the wavelength region.
When having a _max, not preferable in terms of light fractions it is undesirable to have a lambda _max in the short wavelength side, in combination with the coupler compound, the image fixing property, image stability, both in terms of the hue of magenta color . Further, the diazonium salt compound preferably has a solubility in water of 2% or less and a solubility in ethyl acetate of 10% or more.

On the other hand, in the heat-sensitive recording material of the present invention, the coupler compound which forms a dye by a coupling reaction with the diazonium salt compound contained in the heat-sensitive recording layer includes a basic atmosphere and / or a neutral atmosphere. Any compound can be used as long as it forms a dye by a coupling reaction with a diazonium salt compound. All so-called 4-equivalent couplers for silver halide photographic materials can be used as couplers. These can be selected according to the desired hue.

Suitable examples of the coupler compound include a so-called active methylene compound having a methylene group next to a carbonyl group, a phenol derivative, a naphthol derivative, and the like. The details of the coupler are described in
No. 201483, JP-A-7-223267, JP-A-7-223
-223368, JP-A-7-323660, Japanese Patent Application No. 5-278608, Japanese Patent Application No. 5-297024, Japanese Patent Application No. 6-18669, Japanese Patent Application No. 6-18670, Japanese Patent Application No. 7-316280. Japanese Patent Application Nos. 8-027095, 8-027096, 8-030799, 8-030799, 8-12610, 8-132394, 8-358755, and 8-358755. No. 8-358756,
It is described in each gazette of Japanese Patent Application No. 9-069990.

In the present invention, the following embodiments are particularly preferred as the diazonium salt compound and the coupler compound contained in the heat-sensitive recording layer of the heat-sensitive recording material. That is, the diazonium salt compound is represented by the general formula (II):
-Disubstituted amino-2-alkoxybenzenediazonium salt, wherein the coupler compound is represented by the general formula (II)
An embodiment containing at least one of the compound represented by I) and the compound represented by the general formula (IV) is exemplified. Hereinafter, the preferred diazonium salt compounds and coupler compounds will be described.

[Diazonium Salt Compound] In the heat-sensitive recording material of the present invention, the diazonium salt compound contained in the heat-sensitive recording layer is a 4-disubstituted amino compound represented by the following general formula (II): It is preferable to contain a -2-alkoxybenzenediazonium salt.

[0042]

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In the general formula (II), R ₄ , R ₅ and R ₆ each independently represent an alkyl group, an aralkyl group or an aryl group. R ₄ and R ₅ may form a ring together with the nitrogen atom. X represents an acid anion.

In the general formula (II), the groups represented by R ₄ , R ₅ and R ₆ are an alkyl group having 1 to 18 carbon atoms, an aralkyl group having 7 to 21 carbon atoms, and a group having 6 carbon atoms. ~
Preferred are 20 aryl groups, which may further have a substituent.

In the above formula (II), when R ₄ , R ₅ and R ₆ further have a substituent, the substituent may be an alkyl group, an aryl group, an alkyloxy group, an aryloxy group, an alkylthio group. , An arylthio group, an acyl group, an alkoxycarbonyl group, an acyloxy group, a carbamoyl group, an alkylsulfonyl group, an arylsulfonyl group, a sulfamoyl group, an acylamino group, a halogen atom, and a cyano group.

In the general formula (II), the total number of carbon atoms of R ₄ , R ₅ and R ₆ is preferably 12 or more, more preferably 14 or more, from the viewpoint of oil solubility.

In the general formula (II), specific examples of the acid of the acid anion represented by X include, for example, those having 1 to 1 carbon atoms.
Up to 9 polyfluoroalkylcarboxylic acids, 1 to 1 carbon atoms
Up to 9 polyfluoroalkylsulfonic acid, boron tetrafluoride, tetraphenylboron, hexafluorophosphoric acid,
Aromatic carboxylic acids, aromatic sulfonic acids and the like are preferred. Further, a diazonium salt can be stabilized by forming a complex compound using zinc chloride, cadmium chloride, tin chloride, or the like.

In the heat-sensitive recording material of the present invention, the 4-disubstituted amino-2-alkoxybenzenediazonium salt represented by the general formula (II) has a melting point of 30.degree.
0 ° C. is preferred, but from the viewpoint of handling, 50 ° C. to 1
Those at 50 ° C. are more preferred.

In the heat-sensitive recording material of the present invention, as a mode in which the diazonium salt compound is contained in the heat-sensitive recording layer of the heat-sensitive recording material of the present invention, when the diazonium salt compound is contained in a microcapsule described later, the diazonium salt may be added to an appropriate solvent. Since the compound is used after being dissolved, it is preferable that the compound has appropriate solubility in these solvents and low water solubility.
Specifically, it is preferable that the organic solvent used has a solubility of 5% or more and the solubility in water is 1% or less.

The 4-disubstituted amino-2-alkoxybenzenediazonium salt represented by the general formula (II) is preferably contained in the heat-sensitive recording layer in the range of 0.02 to 3 g / m ² , From the point of concentration, in particular, 0.1 to 2 g /
It is preferable to contain m ² within the range.

Hereinafter, specific examples of the 4-disubstituted amino-2-alkoxybenzenediazonium salt represented by the general formula (II) contained in the heat-sensitive recording layer of the heat-sensitive recording material of the present invention (exemplified compound (II) -1) to (II-25)),
The present invention is not limited by these.

[0052]

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[0053]

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[0054]

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[0055]

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In the heat-sensitive recording material of the present invention, the 4-disubstituted amino-2-alkoxybenzenediazonium salt represented by the general formula (II) may be used alone or in combination of two or more. They can be used together. Further, according to various purposes such as hue adjustment, the 4-disubstituted amino-2-alkoxybenzenediazonium salt represented by the general formula (II) can be used in combination with a known diazonium salt compound. The amount of the 4-disubstituted amino-2-alkoxybenzenediazonium salt represented by the general formula (II) is preferably 50% by mass or more of all the diazonium salt compounds used.

Examples of the known diazonium salt compounds which can be used in combination include, for example, 4-diazo-1-dimethylaminobenzene, 4-diazo-2-butoxy-5-chloro-1.
-Dimethylaminobenzene, 4-diazo-1-methylbenzylaminobenzene, 4-diazo-1-ethylhydroxyethylaminobenzene, 4-diazo-1-diethylamino-3-methoxybenzene, 4-diazo-1-morpholinobenzene, 4-diazo-1-morpholino-2,5
-Dibutoxybenzene, 4-diazo-1-toluylmercapto-2,5-diethoxybenzene, 4-diazo-1
-Piperazino-2-methoxy-5-chlorobenzene, 4
-Diazo-1- (N, N-dioctylaminocarbonyl) benzene, 4-diazo-1- (4-tert-octylphenoxy) benzene, 4-diazo-1- (2-ethylhexanoylpiperidino) -2 , 5-Dibutoxybenzene, 4-diazo-1- [α- (2,4-ditert
-Amylphenoxy) butyrylpiperidino] benzene,
4-diazo-1- (4-methoxy) phenylthio-2,
5-diethoxybenzene, 4-diazo-1- (4-methoxy) benzamide-2,5-diethoxybenzene, 4
-Diazo-1-pyrrolidino-2-methoxybenzene and the like are preferred.

A diazonium salt compound which can be used in combination,
Specific examples of the acid forming the diazonium salt include, for example, polyfluoroalkylcarboxylic acids having 1 to 9 carbon atoms, polyfluoroalkylsulfonic acids having 1 to 9 carbon atoms, boron tetrafluoride, tetraphenylboron, hexa Fluorophosphoric acid, aromatic carboxylic acid, aromatic sulfonic acid and the like are preferably exemplified. Further, a diazonium salt can be stabilized by forming a complex compound using lead, cadmium chloride, tin chloride or the like.

[Coupler Compound] In the heat-sensitive recording material of the present invention, the coupler compound contained in the heat-sensitive recording layer is
It is preferable to contain at least one of a compound represented by the following general formula (III) and a compound represented by the following general formula (IV). Further, among the compounds represented by the following general formula (III), those having a total carbon number of 20 or more are more preferable.

[0060]

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In the general formula (III), Y ¹ and Y ²
Are each independently a hydrogen atom, an alkyl group having 1 to 18 carbon atoms, an aralkyl group having 7 to 21 carbon atoms, or a 6 to 2 carbon atoms.
Represents an aryl group of 0.

[0062]

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[0063] In the general formula _{(IV), R 7, R} 8, R
₉ and R ₁₀ are each independently a hydrogen atom, an alkyl group, an aryl group, an aralkyl group, an alkyloxy group, an aryloxy group, an alkylthio group, an arylthio group, an acyl group, an alkoxycarbonyl group, an acyloxy group, a carbamoyl group, a sulfamoyl group. Represents a group, a halogen atom, a cyano group or a nitro group. R ₇ , R ₈ , R ₉ , and R ₁₀ may be the same or different. R ₇ and R ₈ , R ₈ and R ₉ , and R ₉ and R ₁₀ may combine with each other to form a ring.

Here, the compound represented by the general formula (III), that is, the barbituric acid derivative represented by the general formula (III) will be described.

In the general formula (III), Y ¹ and Y ²
May be the same or different and each independently represents a hydrogen atom, an alkyl group having 1 to 18 carbon atoms, an aralkyl group having 7 to 21 carbon atoms, or an aryl group having 6 to 20 carbon atoms.

In the general formula (III), Y ¹ and Y ²
At least one of the groups represented by
An alkyl group of -18, an aralkyl group having 7-21 carbon atoms,
Or an aryl group having 6 to 20 carbon atoms, an alkyl group having 1 to 18 carbon atoms, and 6 carbon atoms.
More preferably, it is an aryl group of from 20 to 20.

In the formula (III), the alkyl group, aralkyl group and aryl group represented by Y ¹ and Y ² may further have a substituent. -C18-C alkyl group, C6-C20 aryl group, hydroxy group, C1-C18 alkyloxy group, C6-C20 aryloxy group, C1-C1
An alkylthio group having 8 carbon atoms, an arylthio group having 6 to 20 carbon atoms, an alkylcarbonyl group having 2 to 25 carbon atoms, and 7 carbon atoms
To 35 arylcarbonyl group, 2 to 25 carbon atom alkoxycarbonyl group, 2 to 20 carbon atom acyloxy group, 2 to 37 carbon atom carbamoyl group, 2 to 35 carbon atom
Acylamino group, an alkylsulfonyl group having 2 to 20 carbon atoms, an arylsulfonyl group having 7 to 20 carbon atoms, an alkylamino group having 1 to 20 carbon atoms, an arylamino group having 6 to 20 carbon atoms, a heterocyclic ring A residue, a halogen atom, a cyano group, and a nitro group are preferable, and
To 18 alkyl groups, alkyloxy groups having 1 to 18 carbon atoms, arylalkyl groups having 6 to 20 carbon atoms, and 2 to 2 carbon atoms
5 alkoxycarbonyl groups and halogen atoms are more preferred. In addition, these substituents may further have a substituent.

Y ¹ and Y ² are bonded to each other to form 2
To trimers may be formed.

Next, in the thermosensitive recording layer of the thermosensitive recording material of the present invention, the thermosensitive recording material is contained in a coupler compound which undergoes a coupling reaction with the 4-disubstituted amino-2-alkoxybenzenediazonium salt represented by the general formula (II). Specific examples (exemplified compounds (III-1) to (III-27)) of the compounds represented by the following general formula (III) are preferably shown below, but the invention is not limited thereto. Not something.

[0070]

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[0071]

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[0072]

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[0073]

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[0074]

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[0075]

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In the heat-sensitive recording material of the present invention, a coupler compound which can be used together with the coupler compound represented by the above general formula (III) for the purpose of hue preparation and the like includes a diazonium salt compound and a coupler in a basic atmosphere. Any compound can be used in combination as long as it forms a dye by ringing.

Examples of the coupler compound which can be used in combination include:
For example, there are a so-called active methylene compound having a methylene group next to a carbonyl group, a phenol derivative, a naphthol derivative, and the like. Specific examples include the following.

For example, resorcin, phloroglucin,
Sodium 2,3-dihydroxynaphthalene-6-sulfonate, morpholinopropylamide 1-hydroxy-2-naphthoate, 1,5-dihydroxynaphthalene, 2,
3-dihydroxynaphthalene, 2,3-dihydroxy-
6-sulfo-naphthalene, 2-hydroxy-3-naphthoic acid morpholinopropylamide, 2-hydroxy-3-
Naphthoic acid octylamide, 2-hydroxy-3-naphthoic acid anilide, benzoylacetonilide, 1-phenyl-3-methyl-5-pyrazolone, 1- (2,4,6-
Trichlorophenyl) -3-anilino-5-pyrazolone, 2- {3- [α- (2,4-di-tert-aminophenoxy) -butanamide] ben {amide} phenol, 2,4-bis- (benzoylacetamino ) Toluene, 1,3-bis- (pivaloylacetoaminomethyl)
Benzene and the like are preferred.

Next, the compound represented by the following formula (IV), that is, the 4-hydroxycoumarin derivative represented by the following formula (IV) will be described.

[0080]

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In the general formula (IV), R₇, R₈, R
₉, And R_TenIs independently a hydrogen atom, an alkyl group,
Aryl group, aralkyl group, alkyloxy group, aryl
Ruoxy group, alkylthio group, arylthio group, acyl
Group, alkoxycarbonyl group, acyloxy group, carba
Moyl group, sulfamoyl group, halogen atom, cyano group
Or a nitro group. R₇, R₈, R₉, And R₇, R₈,
R₉, And R_TenMay be the same or different
No. R₇And R₈, R₈And R₉, And R₉And R_TenAre connected to each other
They may combine to form a ring. And R_TenAre the same
May also be different. R₇And R₈, R₈And R₉, And R ₉
And R_TenMay combine with each other to form a ring.

Of the above R ₇ , R ₈ , R ₉ and R ₁₀ ,
A hydrogen atom, a substituted or unsubstituted alkyl group having 4 to 36 carbon atoms, a substituted or unsubstituted aryl group having 6 to 20 carbon atoms, a substituted or unsubstituted aralkyl group having 7 to 21 carbon atoms, A substituted or unsubstituted alkyloxy group having 6 to 20 carbon atoms, a substituted or unsubstituted aryloxy group having 6 to 20 carbon atoms, a substituted or unsubstituted alkylthio group having 4 to 36 carbon atoms,
To 20 arylthio groups, substituted or unsubstituted alkoxycarbonyl groups having 2 to 25 carbon atoms, substituted or unsubstituted acyloxy groups having 2 to 20 carbon atoms, substituted or unsubstituted carbamoyl groups having 2 to 37 carbon atoms, carbon atoms A substituted or unsubstituted sulfamoyl group of Formulas 2 to 35 and a halogen atom are more preferred.

When the groups represented by R ₇ , R ₈ , R ₉ and R ₁₀ further have a substituent, the substituent may be an alkyl group, an aryl group, an aralkyl group, an alkyloxy group,
Aryloxy group, alkylthio group, arylthio group,
Acyl group, alkoxycarbonyl group, acyloxy group,
Carbamoyl group, sulfamoyl group, acylamino group,
A halogen atom or the like is preferable, and among the substituents, an alkyl group having 1 to 36 carbon atoms, an aryl group having 6 to 20 carbon atoms, an aralkyl group having 7 to 21 carbon atoms, an alkyloxy group having 1 to 36 carbon atoms, Aryloxy group having 6 to 20 carbon atoms, alkylthio group having 1 to 36 carbon atoms, 6 to 20 carbon atoms
Arylthio group, an alkylcarbonyl group having 2 to 25 carbon atoms, an arylcarbonyl group having 7 to 35 carbon atoms, an alkoxycarbonyl group having 2 to 25 carbon atoms, an acyloxy group having 2 to 20 carbon atoms, and carbamoyl having 2 to 37 carbon atoms Group, an acylamino group having 2 to 35 carbon atoms, a halogen atom, a cyano group, and the like are more preferable.

In the general formula (IV), R ₇ , R ₈ , R
The total number of carbon atoms of ₉ and R ₁₀ is preferably 12 or more, and more preferably 14 or more from the viewpoint of oil solubility. Further, among the compounds represented by the general formula (IV), a compound represented by the following general formula (V) is particularly preferable.

[0085]

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In the general formula (V), R ₁₁ represents a hydrogen atom, an alkyl group, an aryl group, an aralkyl group, an acyl group, an alkoxycarbonyl group, an acyloxy group, a carbamoyl group, a sulfamoyl group, or a halogen atom. R
₁₂ , R ₁₃ and R ₁₄ each independently represent a hydrogen atom, an alkyl group, an aryl group, an aralkyl group, an alkyloxy group,
Aryloxy group, alkylthio group, arylthio group,
Acyl group, alkoxycarbonyl group, acyloxy group,
Represents a carbamoyl group or a sulfamoyl group. Y is
Represents an oxygen atom or a sulfur atom. k + 1 represents an integer of 1 to 4. Here, 1 represents an integer of 1 or more. n is 1
Represents an integer of 10 to 10.

Among the above-mentioned R ₁₁ , a hydrogen atom and carbon number 4 to
Preferred are 36 substituted or unsubstituted alkyl groups, 6 to 20 substituted or unsubstituted aryl groups, and halogen atoms. Among the above R ₁₂ , R ₁₃ and R ₁₄ , a hydrogen atom,
A substituted or unsubstituted alkyl group having 1 to 24 carbon atoms, a substituted or unsubstituted aryl group having 6 to 20 carbon atoms, 7 to 2 carbon atoms
1 substituted or unsubstituted aralkyl group, a substituted or unsubstituted alkyloxy group having 4 to 36 carbon atoms, a substituted or unsubstituted aryloxy group having 6 to 20 carbon atoms, substituted or unsubstituted having 4 to 36 carbon atoms Alkylthio group, a substituted or unsubstituted arylthio group having 6 to 20 carbon atoms, a substituted or unsubstituted alkoxycarbonyl group having 2 to 25 carbon atoms, 2 to 20 carbon atoms
Or a substituted or unsubstituted carbamoyl group having 2 to 37 carbon atoms, or a substituted or unsubstituted sulfamoyl group having 2 to 35 carbon atoms. Among Y, an oxygen atom is preferable.

Next, specific examples (exemplified compounds (IV-1) to (IV-24)) of the coupler compound represented by formula (IV) in the heat-sensitive recording material of the present invention are shown below.
The present invention is not limited by these.

[0089]

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[0090]

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[0091]

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[0092]

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[0093]

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In the heat-sensitive recording material of the present invention, a dye may be obtained by coupling with a diazonium salt compound in a basic atmosphere, if necessary, together with the coupler compound represented by the general formula (IV) for the purpose of adjusting hue. A well-known coupler compound that forms However, 50% by mass or more of all the coupler compounds used are represented by the general formula (I)
It is preferably a compound represented by V). As the coupler compound that can be used in combination, for example, a so-called active methylene compound having a methylene group next to a carbonyl group,
There are phenol derivatives and naphthol derivatives, and specific examples include the following.

For example, resorcin, phloroglucin,
Sodium 2,3-dihydroxynaphthalene-6-sulfonate, morpholinopropylamide 1-hydroxy-2-naphthoate, 1,5-dihydroxynaphthalene, 2,
3-dihydroxynaphthalene, 2,3-dihydroxy-
6-sulfo-naphthalene, 2-hydroxy-3-naphthoic acid morpholinopropylamide, 2-hydroxy-3-
Naphthoic acid octylamide, 2-hydroxy-3-naphthoic acid anilide, benzoylacetonilide, 1-phenyl-3-methyl-5-pyrazolone, 1- (2,4,6-
Trichlorophenyl) -3-anilino-5-pyrazolone, 2- {3- [α- (2,4-di-tert-amylphenoxy) -butanamide] ben {amide} phenol,
2,4-bis- (benzoylacetoamino) toluene,
1,3-bis- (pivaloylacetoaminomethyl) benzene and the like are preferred.

<Other Components> Next, other components in the heat-sensitive recording layer of the heat-sensitive recording material of the present invention will be described. In the heat-sensitive recording material of the present invention, in addition to providing a heat-sensitive recording layer containing the diazonium salt compound and the coupler compound as a color-forming component, a combination of an electron-donating dye precursor and an electron-accepting compound as a color-forming component (leuco coloring) Agent) can be provided. That is, in a heat-sensitive recording material provided with a plurality of heat-sensitive recording layers, at least one layer can be a layer containing a leuco-based coloring agent. In addition, a sensitizer, an organic basic substance, and the like can be added.

[Electron-donating Dye Precursor and Electron-Accepting Compound] Examples of the electron-donating dye precursor include triarylmethane compounds, diphenylmethane compounds, thiazine compounds, xanthene compounds, and spiropyran compounds. Among them, triarylmethane compounds and xanthene compounds are particularly useful because of their high color density.
Examples of some of these are 3,3-bis (p-dimethylaminophenyl) -6-dimethylaminophthalide (that is, crystal violet lactone), 3,3-bis (p-dimethylamino) phthalide, (P-dimethylaminophenyl) -3- (1,3-dimethylindol-3-yl) phthalide, 3- (p-dimethylaminophenyl) -3- (2-methylindol-3-yl) phthalide, 3- (O-methyl-p-diethylaminophenyl) -3- (2-methylindol-3-yl) phthalide, 4,4′-bis (dimethylamino) benzhydrin benzyl ether, N-halophenylleucouramine, N -2,4,5-trichlorophenylleuco auramine, rhodamine-B-anilinolactam, rhodamine (p-nitroanilino) la Kutam, Rhodamine-B-
(P-chloroanilino) lactam, 2-benzylamino-6-diethylaminofluoran, 2-anilino-6
Diethylaminofluoran, 2-anilino-3-methyl-6-diethylaminofluoran, 2-anilino-3-
Methyl-6-cyclohexylmethylaminofluoran,
2-anilino-3-methyl-6-isoamylethylaminofluoran, 2- (o-chloroanilino) -6-diethylaminofluoran, 2-octylamino-6-diethylaminofluoran, 2-ethoxyethylamino-3
-Chloro-2-diethylaminofluoran, 2-anilino-3-chloro-6-diethylaminofluoran, benzoylleucomethylene blue, p-nitrobenzylleucomethylene blue, 3-methyl-spiro-dinaphthopyran, 3-ethyl-spiro-dinaphthopyran, 3,3'-
Dichloro-spiro-dinaphthopyran, 3-benzylspirodinaphthopyran, 3-propyl-spiro-dibenzopyran and the like are preferred.

The electron accepting compound is preferably a phenol derivative, a salicylic acid derivative, a hydroxybenzoic acid ester, etc., and more preferably a bisphenol or a hydroxybenzoic acid ester. Some examples of these include 2,2-bis (p-hydroxyphenyl) propane (ie, bisphenol A), 4,4 ′-(p-phenylenediisopropylidene) diphenol (ie, bisphenol P), 2,2-bis (p-hydroxyphenyl) pentane, 2,2-bis (p-hydroxyphenyl) ethane, 2,2-bis (p-hydroxyphenyl)
Butane, 2,2-bis (4'-hydroxy-3 ', 5'
-Dichlorophenyl) propane, 1,1- (p-hydroxyphenyl) cyclohexane, 1,1- (p-hydroxyphenyl) propane, 1,1- (p-hydroxyphenyl) pentane, 1,1- (p-hydroxyphenyl) ) -2-Ethylhexane, 3,5-di (α-methylbenzyl) salicylic acid and its polyvalent metal salts, 3,5-di (tert-butyl) salicylic acid and its polyvalent metal salts, 3-α, α- Dimethylbenzyl salicylic acid and its polyvalent metal salts, butyl p-hydroxybenzoate, benzyl p-hydroxybenzoate, p-hydroxybenzoic acid
Preferable examples include 2-ethylhexyl, p-phenylphenol, p-cumylphenol and the like.

[Sensitizer] The sensitizer is preferably a low-melting-point organic compound having an aromatic group and a polar group in the molecule. Examples thereof include benzyl p-benzyloxybenzoate and α- Naphthyl benzyl ether, β-naphthyl benzyl ether, β-naphthoic acid phenyl ester, α-
Hydroxy-β-naphthoic acid phenyl ester, β-naphthol- (p-chlorobenzyl) ether, 1,4-
Butanediol phenyl ether, 1,4-butanediol-p-methylphenyl ether, 1,4-butanediol-p-ethylphenyl ether, 1,4-butanediol-m-methylphenyl ether, 1-phenoxy-2- Preferable examples include (p-tolyloxy) ethane, 1-phenoxy-2- (p-ethylphenoxy) ethane, 1-phenoxy-2- (p-chlorophenoxy) ethane, and p-benzylbiphenyl.

[Organic Basic Substance, etc.] In the heat-sensitive recording material of the present invention, an organic basic substance can be added for the purpose of accelerating the coupling reaction between the diazonium salt compound and the coupler compound. The organic basic substance is 1
These can be used alone or in combination of two or more. Examples of the organic basic substance include nitrogen-containing compounds such as tertiary amines, piperidines, piperazines, amidines, formamidines, pyridines, guanidines, and morpholines.

Among these, N, N'-bis (3-phenoxy-2-hydroxypropyl) piperazine, N, N'-bis [3- (p-methylphenoxy)-
2-hydroxypropyl] piperazine, N, N′-bis [3- (p-methoxyphenoxy) -2-hydroxypropyl] piperazine, N, N′-bis (3-phenylthio-2-hydroxypropyl) piperazine, N, N N'-
Bis [3- (β-naphthoxy) -2-hydroxypropyl] piperazine, N-3- (β-naphthoxy) -2-hydroxypropyl-N′-methylpiperazine, 1,4-
Piperazines such as bis {[3- (N-methylpiperazino) -2-hydroxy] propyloxy} benzene;

N- [3- (β-naphthoxy) -2-hydroxy] propylmorpholine, 1,4-bis [(3-morpholino-2-hydroxy) propyloxy] benzene, 1,3-bis [(3- Morpholinos such as morpholino-2-hydroxy) propyloxy] benzene, N
Preferred are piperidines such as-(3-phenoxy-2-hydroxypropyl) piperidine and N-dodecylpiperidine, and guanidines such as triphenylguanidine, tricyclohexylguanidine and dicyclohexylphenylguanidine.

In the present invention, the amount of the organic basic substance to be used is 1 part by mass per 1 part by mass of the diazonium salt compound.
It is preferably from 10 to 10 parts by mass.

In the heat-sensitive recording material of the present invention, in addition to the organic basic substance, a coloring aid may be added for the purpose of accelerating the coloring reaction. The coloring aid includes a substance that increases the coloring density at the time of heating recording or lowers the minimum coloring temperature, and lowers the melting point of a coupler compound, an organic basic substance, a diazonium salt compound, or the like, or reduces the capsule wall. Is intended to create a situation in which a diazonium salt compound, a basic substance, a coupler, and the like easily react due to the action of lowering the softening point.

Examples of the coloring aid include phenol derivatives, naphthol derivatives, alkoxy-substituted benzenes, alkoxy-substituted naphthalenes, hydroxy compounds, amides, etc. in the heat-sensitive recording layer so that rapid and complete thermal development can be carried out with low energy. Compounds, sulfonamide compounds and the like can be added. It is considered that these compounds reduce the melting point of the coupler compound or the basic substance, or improve the heat permeability of the microcapsule wall, thereby enabling a high color density.

The coloring aid also includes a heat-meltable substance. The heat-meltable substance is a substance that is solid at normal temperature and melts by heating and has a melting point of 50 ° C. to 150 ° C., and dissolves a diazonium salt compound, a coupler compound, or an organic basic substance. Specific examples of these compounds include carboxylic amides, N-substituted carboxylic amides,
Ketone compounds, urea compounds, esters and the like can be mentioned.

The heat-sensitive recording material of the present invention contains a free radical generator (a compound that generates free radicals upon irradiation with light) used in a photopolymerizable composition or the like for the purpose of reducing yellowing of the background after fixing. Can also be added. Examples of the free radical generator include aromatic ketones, quinones, benzoin, benzoin ethers, azo compounds, organic disulfides, acyl oxime esters, and the like. The amount of the free radical generator is preferably 0.01 to 5 parts by mass per 1 part by mass of the diazonium salt compound.

Similarly, for the purpose of reducing yellowing, a polymerizable compound having an ethylenically unsaturated bond (hereinafter sometimes referred to as “vinyl monomer”) may be contained. The vinyl monomer refers to at least one ethylenically unsaturated bond (vinyl group,
Compound having a chemical form of a monomer or a prepolymer. Specific examples include unsaturated carboxylic acids and salts thereof, esters of unsaturated carboxylic acids and aliphatic polyhydric alcohols, and amide compounds of unsaturated carboxylic acids and aliphatic polyamines.

The vinyl monomer is preferably used in a ratio of 0.2 to 20 parts by mass with respect to 1 part by mass of the diazonium salt compound. The free radical generator and the vinyl monomer can be used together with a diazonium compound in a microcapsule described later. In the present invention, in addition to the above components, citric acid, tartaric acid as an acid stabilizer,
Oxalic acid, boric acid, phosphoric acid, pyrophosphoric acid and the like can also be added.

In the heat-sensitive recording material of the present invention, the diazonium salt compound, a coupler compound which undergoes a coupling reaction with the diazonium salt compound, an electron-donating dye precursor and an electron-accepting compound, a sensitizer, an organic basic substance, etc. Is not particularly limited. Examples of the use form include (1) a method of using a solid dispersion,
There are (2) a method of emulsifying and dispersing, (3) a method of dispersing and using a polymer, (4) a method of dispersing and using latex, and (5) a method of using microencapsulation. However, from the viewpoint of storage stability, the method of microencapsulation is preferred, and particularly in a color developing system utilizing the reaction between a diazonium salt compound and a coupler compound, the case where the diazonium salt compound is microencapsulated is an electron-donating dye. In a color-forming system utilizing the reaction between the precursor and the electron-accepting compound, it is preferable that the electron-donating colorless dye precursor is microencapsulated.

The coupler compound capable of undergoing a coupling reaction with the diazonium salt compound can be used as a solid dispersion with an organic basic substance or the like and a water-soluble polymer by a sand mill or the like. It is particularly preferable to use them. Preferred water-soluble polymers include water-soluble polymers used when preparing microcapsules described later (for example, see
9-190886). In this case, the coupler component, the organic basic substance, the color-forming auxiliary, and the like are added to the water-soluble polymer solution in an amount of 5 to 40% by mass. The diameter of the dispersed or emulsified particles is preferably 10 μm or less.

<Method of Microencapsulation> Next, the method of microencapsulation will be described. As the microencapsulation method, a conventionally known microcapsule method can be used. That is, the coloring agent, the additive and the microcapsule wall precursor are dissolved in a water-insoluble or insoluble organic solvent, added to an aqueous solution of a water-soluble polymer, emulsified and dispersed using a homogenizer or the like, and heated. Thus, the microcapsule can be prepared by forming a polymer material as a wall film at the oil / water interface.

Examples of the organic solvent include low-boiling auxiliary solvents such as acetate, methylene chloride, and cyclohexanone, and / or phosphates, phthalates, acrylates, methacrylates, other carboxylic esters, fatty acid amides, and the like. Alkylated biphenyl, alkylated terphenyl, alkylated naphthalene,
Diarylethane, chlorinated paraffin, alcoholic,
Phenol type, ether type, monoolefin type, epoxy type and the like can be mentioned. Specific examples include tricresyl phosphate, trioctyl phosphate, octyl diphenyl phosphate, tricyclohexyl phosphate, dibutyl phthalate, dioctyl phthalate, dilaurate phthalate, dicyclohexyl phthalate, butyl olefin, diethylene glycol benzoate, dioctyl sebacate, Dibutyl sebacate, dioctyl adipate, trioctyl trimellitate, acetyl triethyl citrate, octyl maleate, dibutyl maleate, isoamyl biphenyl, chlorinated paraffin, diisopropyl naphthalene,
1,1'-ditolylethane, 2,4-ditertiaryamylphenol, N, N-dibutyl-2-butoxy-5
Tert-octylaniline, hydroxybenzoic acid 2-
Ethylhexyl ester, high-boiling oils such as polyethylene glycol, and among them, alcohols, phosphates, carboxylic esters,
Preferred are alkylated biphenyls, alkylated terphenyls, alkylated naphthalenes, and diarylethanes. Further, an anti-carbonizing agent such as hindered phenol and hindered amine may be added to the high boiling point oil. Further, as the oil, those having an unsaturated fatty acid are particularly desirable,
α-methylstyrene dimer and the like.
Examples of the α-methylstyrene dimer include “MSD100” manufactured by Mitsui Toatsu Chemicals, Inc.

As the water-soluble polymer, a water-soluble polymer such as polyvinyl alcohol is used, but an emulsion or latex of a hydrophobic polymer may be used in combination. Examples of the water-soluble polymer include polyvinyl alcohol, silanol-modified polyvinyl alcohol, carboxy-modified polyvinyl alcohol, amino-modified polyvinyl alcohol, itaconic acid-modified polyvinyl alcohol, styrene-maleic anhydride copolymer, butadiene-maleic anhydride copolymer, Ethylene-maleic anhydride copolymer, isobutylene-maleic anhydride copolymer, polyacrylamide, polystyrenesulfonic acid, polyvinylpyrrolidone, ethylene-acrylic acid copolymer, gelatin and the like are preferable, and among them, carboxy-modified polyvinyl alcohol is more preferable. preferable. As the emulsion or latex of the hydrophobic polymer, a styrene-butadiene copolymer, a carboxy-modified styrene-butadiene copolymer, an acrylonitrile-butadiene copolymer, or the like is preferable. At this time, a conventionally known surfactant or the like may be added as necessary.

Specific examples of the polymer substance which forms the wall film of the microcapsules include polyurethane resin, polyurea resin, polyamide resin, polyester resin, polycarbonate resin, aminoaldehyde resin, melamine resin, polystyrene resin, and styrene-acrylate. Copolymer resins, styrene-methacrylate copolymer resins, gelatin, polyvinyl alcohol and the like are preferred. Among these, a polyurethane / polyurea resin is more preferable as the wall material. The microcapsules having a wall film made of the polyurethane / polyurea resin are prepared by mixing a microcapsule wall precursor such as polyvalent isocyanate in a core material to be encapsulated, and emulsifying and dispersing in a water-soluble polymer aqueous solution such as polyvinyl alcohol. It is produced by raising the liquid temperature to cause a polymer forming reaction at the oil droplet interface.

Here, some specific examples of the polyvalent isocyanate compound are shown below. For example, m-phenylene diisocyanate, p-phenylene diisocyanate, 2,
6-tolylene diisocyanate, 2,4-tolylene diisocyanate, naphthalene-1,4-diisocyanate, diphenylmethane-4,4′-diisocyanate,
3,3′-diphenylmethane-4,4′-diisocyanate, xylene-1,4-diisocyanate, 4,4 ′
-Diphenylpropane diisocyanate, trimethylene diisocyanate, hexamethylene diisocyanate,
Propylene-1,2-diisocyanate, butylene-
1,2-diisocyanate, cyclohexylene-1,2
Diisocyanates such as diisocyanate and cyclohexylene-1,4-diisocyanate, 4,4 ′,
Triisocyanates such as 4 ″ -triphenylmethane triisocyanate and toluene-2,4,6-triisocyanate; 4,4′-dimethylphenylmethane-2,
Tetraisocyanates such as 2 ', 5,5'-tetraisocyanate, adducts of hexamethylene diisocyanate and trimethylolpropane, adducts of 2,4-tolylenediisocyanate and trimethylolpropane, xylylenediisocyanate and trimethylol Isocyanate prepolymers such as adducts with propane and adducts of tolylene diisocyanate with hexanetriol, and the like. If necessary, two or more kinds can be used together. Among these, those having three or more isocyanate groups in the molecule are more preferable.

In the method of microencapsulation,
As the organic solvent for dissolving the color former, the additive, and the microcapsule wall precursor, oils shown by emulsification and dispersion can be used. The same applies to a water-soluble polymer. The particle size of the microcapsules is preferably from 0.1 to 1.0 μm, more preferably from 0.2 to 0.7 μm.

<Thermal Recording Layer> The thermosensitive recording material of the present invention comprises:
One or a plurality of the heat-sensitive recording layers may be provided.
When a plurality of coloring agents are provided, it is necessary to use coloring agents having different energies required for coloring. Further, the heat-sensitive recording material of the present invention may be full-color, or may be monocolor, but a diazonium salt compound on a support, a diazo-based coloring agent containing a coupler compound that undergoes a coupling reaction with the diazonium salt compound, and a binder. It is preferable to have at least one heat-sensitive recording layer (light-fixing type heat-sensitive recording layer) whose main component is. For example, as the heat-sensitive recording layer (light-fixing type heat-sensitive recording layer), the maximum absorption wavelength is 360 ± 20 n.
m, a thermosensitive recording layer containing a diazonium salt compound and a coupler compound which undergoes a coupling reaction with the diazonium salt compound to form a color, and a maximum absorption wavelength of 430 ± 40 nm.
And a thermosensitive recording layer containing a diazonium salt compound and a coupler compound that undergoes a coupling reaction with the diazonium salt compound to form a color.

In the case of a full-color thermosensitive recording layer containing cyan, yellow, and magenta, all three layers are formed of a diazo-based coloring agent, or the first thermosensitive recording layer close to the support has an electron donating dye and an electron donating dye. It is preferable that the thermosensitive recording layer is formed of a leuco-based coloring agent containing a receptive compound and the second and third heat-sensitive recording layers are formed of a diazo-based coloring agent.

When all three layers are composed of a diazo-based coloring agent, the maximum absorption wavelength is 340 ± 20 nm, for example, on a support.
A light-fixing first heat-sensitive recording layer containing the following diazonium salt compound and a coupler compound which undergoes a coupling reaction with the diazonium salt compound to form a color;
A second heat-sensitive recording layer of a light fixing type containing a diazonium salt compound having a wavelength of 0 ± 20 nm and a coupler compound which undergoes a coupling reaction with the diazonium salt compound to form a color, and a diazonium salt compound having a maximum absorption wavelength of 430 ± 40 nm And a light-fixing third heat-sensitive recording layer containing a diazonium salt compound and a coupler compound that undergoes a coupling reaction to give a color.

When a leuco coloring agent is used for the first layer, for example, a first heat-sensitive recording layer containing an electron-donating dye and an electron-accepting compound, a maximum absorption wavelength of 360 ± A light-fixing second thermosensitive recording layer containing a diazonium salt compound having a thickness of 20 nm and a coupler compound that undergoes a coupling reaction with the diazonium salt compound to form a color,
A light-fixing third heat-sensitive recording layer containing a diazonium salt compound having a maximum absorption wavelength of 430 ± 40 nm and a coupler compound which reacts with the diazonium salt compound to form a color,
The heat-sensitive recording layer provided with is preferred.

In the various heat-sensitive recording materials, it is preferable to provide a light transmittance adjusting layer and a protective layer described later on the heat-sensitive recording layer.

In the recording method using a heat-sensitive recording material including a plurality of heat-sensitive recording layers of a diazo-based coloring agent, first, a third heat-sensitive recording layer is heated to color the diazonium salt compound and coupler compound contained in the layer. After that, the unreacted diazonium salt compound contained in the third thermosensitive recording layer is decomposed by irradiating light having the maximum absorption wavelength of the diazonium salt compound. Next, sufficient heat is applied to the second heat-sensitive recording layer to develop color, thereby causing the diazonium salt compound and the coupler contained in the layer to develop color. At this time, the third heat-sensitive recording layer is also heated strongly, but does not develop color because the diazonium salt compound has already been decomposed and the color-forming ability has been lost. Further, light of the maximum absorption wavelength of the diazonium salt compound is irradiated to decompose and fix the diazonium salt compound contained in the second thermosensitive recording layer. Finally, the color is developed by applying sufficient heat for the first thermosensitive recording layer to develop color. At this time, the third and second heat-sensitive recording layers are also heated strongly, but the diazonium salt compound has already been decomposed and the color-forming ability has been lost, so that no color is formed. The fixing treatment for the diazonium salt compound in the third layer can be omitted. Further, when the third layer is a leuco-based coloring agent, the other two
The two layers of the heat-sensitive recording layer containing a diazo-based coloring agent are color-fixed in the same manner as described above, and finally, the layer containing a leuco-based coloring agent is heated to develop a color.

<Light Transmittance Adjusting Layer> The light transmittance adjusting layer contains a component functioning as a precursor of an ultraviolet absorber, and is used as an ultraviolet absorber before irradiation with light having a wavelength necessary for fixing. Since it does not function, the light transmittance is high, and when fixing the light-fixing type thermosensitive recording layer, it sufficiently transmits wavelengths in the area required for fixing, and the transmittance of visible light is also high, which is useful for fixing the thermosensitive recording layer. No problem occurs. The precursor of the ultraviolet absorber is preferably contained in the microcapsule. In the present invention, as the compound contained in the light transmittance adjusting layer, the compounds described in JP-A-9-1928 can be used.

The precursor of the ultraviolet absorbent is converted into an ultraviolet absorbent by reacting with light or heat after the light irradiation of the wavelength necessary for fixing the light fixing type thermosensitive recording layer by light irradiation is completed. As a result, most of the light in the wavelength range necessary for fixing in the ultraviolet region is absorbed by the ultraviolet absorber, the transmittance is reduced, and the light resistance of the heat-sensitive recording material is improved. Because there is no absorption effect,
The visible light transmittance is not substantially changed. At least one light transmittance adjusting layer can be provided in the (light-fixing type) heat-sensitive recording material, and it is particularly preferable that the light transmittance adjusting layer is formed between the light-fixing type heat-sensitive recording layer and the outermost protective layer. The adjustment layer may also serve as the protective layer. The characteristics of the light transmittance adjusting layer can be arbitrarily selected according to the characteristics of the light fixing type thermosensitive recording layer.

<Protective Layer> The protective layer can contain a pigment, a lubricant, a surfactant, a dispersant, a fluorescent brightener, a metal soap, a hardener, an ultraviolet absorber, a crosslinking agent, and the like, together with a binder. As the binder, polyvinyl alcohol,
Methylcellulose, carboxymethylcellulose, hydroxyethylcellulose, starch, gelatin, gum arabic, casein, styrene-maleic anhydride copolymer hydrolyzate, ethylene-maleic anhydride copolymer hydrolyzate, isobutylene-maleic anhydride copolymer A hydrolyzate, polyvinyl alcohol, modified polyvinyl alcohol, polyacrylamide and the like can be appropriately selected and used within a range that does not impair the barrier properties and workability.

Examples of other binders include synthetic rubber latex and synthetic resin emulsions, such as styrene butadiene rubber latex, acrylonitrile-butadiene rubber latex, methyl acrylate-butadiene rubber latex, and vinyl acetate emulsion. . The amount of the binder used is 10 to 500% by mass, and preferably 50 to 400% by mass, based on the pigment contained in the protective layer.

In order to further improve the water resistance, it is effective to use a crosslinking agent and a catalyst for accelerating the reaction.
Specific examples of the crosslinking agent include an epoxy compound, a blocked isocyanate, a vinyl sulfone compound, an aldehyde compound, a methylol compound, boric acid, a carboxylic anhydride, a silane compound, a chelate compound, and a halide. Preferably, the pH can be adjusted to 6.0 to 7.5. Known catalysts such as acids and metal salts can be used as the catalyst, and similarly, the pH of the coating solution is adjusted to 6.0 to 6.0.
Those that can be adjusted to 7.5 are preferred.

As the pigment that can be used in the protective layer of the present invention, all general organic or inorganic pigments can be used.
Specifically, calcium carbonate, aluminum hydroxide, barium sulfate, titanium oxide, talc, wax, kaolin, calcined kaolin, amorphous silica, urea formalin resin powder,
Examples include polyethylene resin powder and benzoguanamine resin powder. These are used alone or in combination of two or more. Suitable examples of the lubricant include zinc stearate, calcium stearate, paraffin wax, and polyethylene wax. As the surfactant, a sulfosuccinic acid-based alkali metal salt, a fluorine-containing surfactant and the like are preferably used in order to uniformly form a protective layer on the heat-sensitive recording layer. 2-
Examples thereof include sodium salts such as ethylhexyl) sulfosuccinic acid, di- (n-hexyl) sulfosuccinic acid, and ammonium salts.

The coating solution for a protective layer of the present invention is obtained by mixing the above components. Further, a release agent, a wax, a water repellent and the like may be added as necessary. The obtained protective layer coating liquid is applied on the thermosensitive coloring layer using a bar coater, an air knife coater, a blade coater, a curtain coater or the like,
Dry to obtain the protective layer of the present invention. However, the protective layer may be applied at the same time as the coloring layer, or the thermosensitive coloring layer may be dried once after the thermosensitive coloring layer is applied, and then applied thereon. Dry coating amount of the protective layer is preferably 0.2~7g / m ^2, more preferably from 1 to 4 g / m ^2. If the coating amount is large, the thermal sensitivity is remarkably reduced, and if the coating amount is too low, the water resistance cannot be maintained. After applying the protective layer, a calendering treatment may be performed as necessary.

<Intermediate Layer> When a plurality of heat-sensitive recording layers are provided, it is preferable to provide an intermediate layer between the heat-sensitive recording layers. In the intermediate layer, similarly to the protective layer, various binders may further contain pigments, lubricants, surfactants, dispersants, fluorescent brighteners, metal soaps, ultraviolet absorbers, and the like. As the binder, those similar to the binder used for the protective layer can be used.

<Support> In the heat-sensitive recording material of the present invention,
As a support, polyethylene terephthalate (PE
T), polyethylene naphthalate (PEN) triacetyl cellulose (TAC), paper, plastic resin laminated paper, synthetic paper, and the like. Further, in order to obtain a transparent thermosensitive recording material, it is necessary to use a transparent support. Examples of the transparent support include a synthetic polymer film such as a polyester film such as polyethylene terephthalate or polybutylene terephthalate, a cellulose triacetate film, or a polyolefin film such as polypropylene or polyethylene.These may be used alone or in combination. Can be. The thickness of the synthetic polymer film is preferably from 25 to 250 μm, more preferably from 50 to 200 μm.

The synthetic polymer film may be colored in an arbitrary hue. As a method of coloring a polymer film, a dye is kneaded with a resin before molding into a film, then a method of forming a film, a coating solution in which the dye is dissolved in an appropriate solvent is prepared, and this is formed into a transparent and colorless liquid. A known coating method, such as a gravure coating method, a roller coating method, a wire coating method, or the like, may be applied to the resin film, and a method of drying the resin film may be used. Among them, a polyester resin such as polyethylene terephthalate or polyethylene naphthalate in which a blue dye is kneaded is formed into a film, which is subjected to a heat treatment, a stretching treatment, and an antistatic treatment.

The heat-sensitive recording layer, the protective layer, the intermediate layer, the anti-reflection layer, the light-blocking layer, the undercoat layer, the back coat layer and the like are coated on a support by a blade coating method, an air knife coating method, a gravure coating method, or a roll coating method. It is applied by a known application method such as a coating application method, a spray application method, a dip application method, and a bar application method.

When the recording surface of the heat-sensitive recording material of the present invention thus obtained is heated by a thermal head or the like, the capsule wall of polyurea or polyurethane is softened, and the coupler and the base compound outside the capsule enter the capsule. Color. After recording, irradiation with light having an absorption wavelength of the diazonium salt compound decomposes the diazonium salt compound and loses reactivity with the coupler compound, so that the image is fixed.

As the fixing light source, various fluorescent lamps, xenon lamps, mercury lamps and the like are used. It is preferable that this emission spectrum substantially coincides with the absorption spectrum of the diazonium salt compound used in the heat-sensitive recording material, since light can be efficiently fixed. Further, the heat-sensitive recording material of the present invention is exposed using a document, decomposes the diazonium salt compound other than the image forming portion to form a latent image, and then heats and develops the heat-sensitive recording material to obtain an image. You can also.

[0137]

EXAMPLES The present invention will be described in more detail with reference to the following Examples, but it should not be construed that the invention is limited thereto.
In addition, all "parts" in an Example show a mass part.

(Example 1) (1) Preparation of coating solution for heat-sensitive recording layer <Preparation of capsule solution containing diazonium salt compound>
Dissolve 2 parts of diazonium salt compound (1) (exemplified compound II-24; decomposed by light having a wavelength of 365 nm) represented by the following structure in 20 parts of ethyl acetate, add 20 parts of alkylnaphthalene, and heat. Mix evenly.

[0139]

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To the obtained solution, 15 parts of xylylene diisocyanate / trimethylpropanol 1/3 adduct as a capsule wall material was added and mixed uniformly to obtain a diazo compound solution.

The resulting diazonium salt compound solution was added to a solution obtained by mixing 54 parts of a 6% by mass aqueous solution of phthalated gelatin and 2 parts of a 2% by mass aqueous solution of sodium dodecylbenzenesulfonate, and emulsified and dispersed with a homogenizer. . After 68 parts of water was added to the obtained emulsified dispersion and uniformly mixed, an encapsulation reaction was performed for 3 hours with stirring at 40 ° C. to obtain a capsule solution of a diazonium salt compound. The average particle size of the capsule was 1.2 μm.

<Preparation of Coupler Emulsion Dispersion> Coupler compound (1) represented by the following structural formula (exemplary compound IV-
2) 2 parts, 1,2,3-triphenylguanidine 2 parts,
0.3 parts of tricresyl phosphate, 0.1 part of diethyl maleate, and 2 parts of ADK STAB 1500 (manufactured by Asahi Denka Co., Ltd.) were dissolved in 10 parts of ethyl acetate. 20 parts of a 6% by mass aqueous solution of lime-processed gelatin and 2% by mass of sodium dodecylbenzenesulfonate were obtained.
After pouring into an aqueous solution obtained by mixing two parts of the aqueous solution, the mixture was emulsified for 10 minutes using a homogenizer to obtain a coupler emulsion dispersion.

[0143]

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<Preparation of coating solution for heat-sensitive recording layer> The coupler emulsified dispersion and the capsule solution containing the diazonium salt compound (1) were mixed at a mass ratio of 3/2 (coupler emulsified dispersion / containing diazonium salt compound. To prepare a magenta layer heat-sensitive recording layer coating solution.

(2) Preparation of protective layer coating solution Itaconic acid-modified polyvinyl alcohol (KL-318;
A mixture of 100 parts of a 6% aqueous solution (trade name, manufactured by Kuraray Co., Ltd.) and 10 parts of a dispersion of 30% epoxy-modified polyamide (FL-71; trade name, manufactured by Toho Chemical Co., Ltd.) was mixed with 40% of zinc stearate. Of the dispersion (Hydrin Z; trade name, manufactured by Chukyo Yushi Co., Ltd.) was uniformly mixed to obtain a protective layer coating solution.

(3) Preparation of heat-sensitive recording material On a photographic paper support obtained by laminating polyethylene on a high-quality paper, a heat-sensitive recording layer coating solution and a protective layer coating solution were sequentially coated with a wire bar and dried at 50 ° C. Was carried out to obtain an intended heat-sensitive recording material. The coating amount as a solid content was 7.8 each.
g / m ² and 1.2 g / m ² .

(Embodiment 2) Adekastab 15 of Embodiment 1
A heat-sensitive recording material was prepared in the same manner except that 00 was changed to SL-TNP (manufactured by Sumitomo Chemical Co., Ltd.). (Example 3) A thermosensitive recording material was produced in the same manner as in Example 1 except that ADK STAB 1500 was changed to ADK STAB 329K (trade name, manufactured by Asahi Denka Co., Ltd.). (Example 4) A thermosensitive recording material was produced in the same manner as in Example 1 except that ADK STAB 1500 was changed to ADK STAB 2112 (trade name, manufactured by Asahi Denka Co., Ltd.). (Example 5) The diazonium salt compound (1) of Example 1 was changed to a diazonium salt compound (2) (exemplified compound II-25) represented by the following structure, and a coupler compound (1) was represented by the following structure. Coupler compound (2) (exemplary compound
A heat-sensitive recording material was prepared in the same manner except that III-1) was used.

[0148]

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[0149]

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(Comparative Example 1) Adekastab 15 of Example 1
A heat-sensitive recording material was produced in the same manner as in Example 1 except that 00 was not used. (Comparative Example 2) A thermosensitive recording material was produced in the same manner as in Example 4 except that the ADK STAB 1500 of Example 4 was not used.

(Comparative Example 3) Adekastab 15 of Example 1
00 is IRGAFOS P-EPQ having the following structure
(Trade name, manufactured by Ciba Specialty Chemicals), except that a thermosensitive recording material was prepared in the same manner.

[0152]

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(Comparative Example 4) Adekastab 15 of Example 1
A heat-sensitive recording material was produced in the same manner except that 00 was changed to ADK STAB AO503A (trade name, manufactured by Asahi Denka Co., Ltd.) having the following structure.

[0154]

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[Evaluation of Thermosensitive Recording Material] (Image Lightfastness Test of Thermosensitive Recording Material) The image lightfastness of the thermosensitive recording materials obtained in Examples 1 to 5 and Comparative Examples 1 to 4 was evaluated as follows.
Evaluation was performed by the following method. The evaluation conditions are as follows. Color is developed using a thermal head KST type (manufactured by Kyocera Corporation) so that the magenta color density becomes 1.0.
A magenta image area formed by irradiating with a UV lamp of W for 20 seconds and fixing was irradiated with light continuously for 24 hours using a super xenon weather meter (manufactured by Suga Test Instruments Co., Ltd.), and then the density of the image area was changed. Is measured and the residual rate (%)
I asked. It can be said that the higher the density (residual rate) of the image area after light irradiation, the better the image light resistance. The measurement results are shown in Table 1 below. Similarly, the magenta image area was irradiated with light at 32,000 lux for 72 hours continuously using a fluorescent lamp light resistance tester, and then the density of the image area was measured to determine the residual ratio (%). The measurement results are shown in Table 1 below.

[0156]

[Table 1]

As shown in Table 1, the heat-sensitive recording material of the present invention using the phosphite-based antioxidant represented by the general formula (I) is excellent in recorded image light resistance. It became clear.

Example 6 (1) Preparation of Support A wood pulp consisting of 100 parts of LBKP was subjected to 300 cc Canadian freeness using a double disc refiner.
Beated until 0.5 parts of epoxidized behenamide, 1.0 part of anionic polyacrylamide, 0.1 part of polyamide polyamine epichlorohydrin, and 0.5 part of cationic polyacrylamide were added at an absolute dry weight ratio to pulp, A base paper having a basis weight of 100 g / m ² is formed by a fourdrinier paper machine, the surface size of polyvinyl alcohol is set to an absolute dry weight of 1.0 g / m ² , and a density of 1.0 is obtained by calendering.
Was adjusted.

After performing a corona discharge treatment on the wire surface (back surface) side of the base paper, high-density polyethylene was coated to a resin thickness of 30 μm using a melt extruder to form a resin layer composed of a matte surface. This surface is called the back surface). After a corona discharge treatment on the polyethylene-coated surface of the back surface, aluminum oxide (manufactured by Nissan Chemical Industries, Ltd .; "Alumina Sol 100") / silicon dioxide (manufactured by Nissan Chemical Industries, Ltd .; "Snowtex O") as an antistatic agent ") =
1/2 (mass ratio) is dispersed in water and the mass after drying is 0.1.
2 g / m ^{2 was} applied (this is called back PE lamination product).

Further, a corona discharge treatment was performed on the felt surface (front surface) side of the base paper, and a low-density polyethylene containing 10% by mass of titanium dioxide and a small amount of ultramarine was applied to a resin thickness of 40 μm using a melt extruder. Melt extrusion coating was performed to form a resin layer having a glossy surface (this surface is referred to as a front surface). After the corona discharge treatment on the polyethylene coated side of the front side, the gelatin undercoat was dried by a weight of 0.1%.
g / m ² .

(2) Preparation of Undercoat Layer Liquid Swellable synthetic mica “ME100” (manufactured by Corp Chemical Co., Ltd.)
97.5 parts by mass of water was added to 2.5 parts by mass, and the mixture was dispersed with a dynamill. This was added to 200 g of a 5% by mass aqueous solution of gelatin at 40 ° C., stirred for 30 minutes, and 20 cc of the following surfactant-1 (5% by mass) was added to prepare an undercoat layer solution.

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(3) Preparation of Cyan Thermosensitive Recording Layer Solution <Preparation of Capsule Solution Containing Electron Donating Dye Precursor> Solution A 3- (o-methyl-p-dimethylaminophenyl) -3
5 parts of-(1'-ethyl-2'-methylindol-3-yl) phthalide (electron-donating dye precursor) is dissolved in 20 parts of ethyl acetate, and 20 parts of alkylnaphthalene (high boiling point solvent) is added thereto. Add and heat to mix evenly.
To the obtained solution, 20 parts of a 1/3 adduct of xylylene diisocyanate / trimethylolpropane was added, and the mixture was stirred uniformly to prepare solution A. Solution B A solution B was prepared by adding 2 parts of a 2% by weight aqueous solution of sodium dodecylsulfonate to 54 parts of a 6% by weight aqueous solution of phthalated gelatin.

Solution A was added to solution B and emulsified and dispersed using a homogenizer to obtain an emulsified dispersion. 68 parts of water is added to the obtained emulsified dispersion, mixed and homogenized, and then the mixture is heated to 50 ° C. while stirring to encapsulate the microcapsules so that the average particle size of the microcapsules becomes 1.2 μm. The reaction was performed for 3 hours to obtain a capsule liquid.

<Preparation of developer emulsified dispersion> 1,1- (p
-Hydroxyphenyl) -2-ethylhexane (developer) 2.5 parts, tricresyl phosphate 0.3 part and diethyl maleate 0.1 part were dissolved in ethyl acetate 10 parts. The obtained solution was added to a solution obtained by mixing 20 parts of a 6% by mass aqueous solution of gelatin and 2 parts of a 2% by mass aqueous solution of sodium dodecylsulfonate, and emulsified for 10 minutes using a homogenizer to obtain an emulsified dispersion. .

<Preparation of Coating Solution> SBR latex (manufactured by Sumitomo Nogatack; "SN-307") was added to the capsule solution containing the electron-donating dye precursor prepared above at 40% by mass based on the solid content of the capsule. Then, the developer emulsified dispersion was mixed with the capsule liquid containing the electron-donating dye precursor so that the weight ratio became 1/4 to obtain a cyan layer coating liquid.

(4) Preparation of magenta heat-sensitive recording layer liquid <Preparation of capsule liquid containing diazonium salt compound>
The diazonium salt compound (1) (36) represented by the following structure
2 parts) was dissolved in 20 parts of ethyl acetate, and 20 parts of alkylnaphthalene was further added, and the mixture was heated and uniformly mixed.

[0168]

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To the obtained solution, 15 parts of xylylene diisocyanate / trimethylpropanol 1/3 adduct was added as a capsule wall material, and the mixture was mixed uniformly to obtain a diazo compound solution.

The obtained diazonium salt compound solution was added to a solution obtained by mixing 54 parts of a 6% by mass aqueous solution of phthalated gelatin and 2 parts of a 2% by mass aqueous solution of sodium dodecylbenzenesulfonate, and emulsified and dispersed with a homogenizer. did. After 68 parts of water was added to the obtained emulsified dispersion and mixed uniformly, an encapsulation reaction was performed for 3 hours with stirring at 40 ° C. to obtain a capsule solution of a diazonium salt compound. The average particle size of the capsule was 1.2 μm.

<Preparation of emulsified dispersion of coupler> 2 parts of coupler compound (1) represented by the following structural formula, 2 parts of 1,2,3-triphenylguanidine, 0.3 part of tricresyl phosphate, and 0 parts of diethyl maleate 1 part and ADK STAB 1500 (manufactured by Asahi Denka Co., Ltd.) in 2 parts
Dissolved in 0 parts. 20 parts of a 6% by mass aqueous solution of lime-processed gelatin and 2 parts of a 2% by mass aqueous solution of sodium dodecylbenzenesulfonate were added to a mixed aqueous solution, and the mixture was emulsified for 10 minutes using a homogenizer. A coupler emulsified dispersion was obtained.

[0172]

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<Preparation of Coating Solution> The mass ratio of the above-mentioned coupler emulsified dispersion to the capsule solution containing the diazonium salt compound is 3/2 (coupler emulsified dispersion / capsule solution containing the diazonium salt compound). This was mixed to prepare a coating solution for the magenta layer.

(5) Preparation of yellow thermosensitive recording layer liquid <Preparation of capsule liquid containing diazonium salt compound>
After dissolving 3.0 parts of 2,5-dibutoxy-4-tolylthiobenzenediazonium hexafluorophosphate (diazonium salt compound: decomposed by light having a wavelength of 420 nm) in 20 parts of ethyl acetate, an alkyl was added thereto as a high boiling solvent. 20 parts of naphthalene and 0.4 parts of the acylphosphine oxide compound (19) were added, and the mixture was heated and uniformly mixed. To the obtained solution, 1/3 of xylylene diisocyanate / trimethylolpropane was added as a capsule wall material.
15 parts of the adduct was added and mixed uniformly to obtain a solution of the diazonium salt compound. The obtained solution of the diazonium salt compound was added to a solution obtained by mixing 54 parts of a 6% by mass aqueous solution of phthalated gelatin and 2 parts of an aqueous solution of sodium dodecylsulfonate, and emulsified and dispersed using a homogenizer. 68 parts of water was added to the obtained emulsified dispersion, and the uniformly mixed solution was heated to 40 ° C. with further stirring to carry out an encapsulation reaction for 3 hours so that the average particle diameter of the capsules was 1.3 μm. A solution was obtained.

<Preparation of Coupler Emulsion Dispersion> 2-Chloro-5- (3- (2,4-di-tert-pentyl) phenoxypropylamino) acetoacetanilide, 2 parts
1 part of 1,2,3-triphenylguanidine, 0.3 part of tricresyl phosphate and 0.1 part of diethyl maleate
Was dissolved in 10 parts of ethyl acetate, and 6% by mass of gelatin was dissolved.
The mixture was put into an aqueous solution obtained by mixing 20 parts of an aqueous solution and 2 parts of a 2% by mass aqueous solution of sodium dodecyl sulfonate, and emulsified for 10 minutes using a homogenizer to obtain an emulsified dispersion.

<Preparation of Coating Solution> The previously prepared coupler emulsified dispersion was mixed with the capsule solution containing the diazonium salt compound in a mass ratio of 3/2 to obtain a coating solution for yellow layer. Was.

(6) Preparation of Intermediate Layer Solution Gelatin (manufactured by Nitta Gelatin Co., Ltd .; trade name “# 75”)
0 ") Polyacrylic acid (manufactured by Nippon Pure Chemical Co., Ltd .; trade name" Julima AC-10L ") in 10 parts of a 15% by mass aqueous solution
3 parts by mass of a 15% by mass aqueous solution were added and mixed uniformly to obtain an intermediate layer liquid.

(7) Preparation of Coating Solution for Light Transmittance Adjusting Layer 1.5 parts of the following compound, R-6 was added as a reducing agent in 0.1 part.
5 parts, ethyl acetate 6.0 parts and tricresyl phosphate 0.8
And thoroughly dissolved. Xylylene diisocyanate / trimethylolpropane (7
5% ethyl acetate solution: Takeda Pharmaceutical Co .;
10N ") was added to this solution and stirred until uniform. 29.7 parts of an aqueous 8% by mass carboxy-modified polyvinyl alcohol (manufactured by Kuraray Co., Ltd .; "KL-318") was prepared, added to the above solution, and emulsified and dispersed by a homogenizer. The obtained emulsion was added to 40 parts of ion-exchanged water and stirred at 40 ° C. for 3 hours to perform an encapsulation reaction. Thereafter, 7.0 parts of an ion exchange resin "Amberlite MB-03" (manufactured by Organo Corporation) was added, and the mixture was further stirred for 1 hour. Thus, a target coating solution was prepared. The average particle size of the capsule is 0.35 μm
Met.

[0179]

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[0180]

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(8) Preparation of Protective Layer Solution EP130 (7% by mass) 100 g Water 50 g Varifine BF21 dispersion (20% by mass) 10 g Surfactant-1 (2% by mass) 5 ml Surfactant-2 (5% by mass) %) 5 ml However, "EP130" Dodecyl-modified polyvinyl alcohol manufactured by Denki Kagaku Kogyo Co., Ltd., and "Varifine BF21 Dispersion" are barium sulfate ultrafine particles manufactured by Sakai Chemical Co., Ltd. The above-mentioned surfactant-2 is represented by the following structural formula.

[0182]

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(9) Preparation of Thermosensitive Recording Material The front side of a paper support laminated with polyethylene was
In order from the support, an undercoat layer solution, a cyan thermosensitive recording layer solution,
Interlayer liquid, magenta thermosensitive recording layer liquid, intermediate layer liquid, yellow feeling
Becomes a thermal recording layer liquid, light transmittance adjusting layer liquid, and protective layer liquid
Multi-layer heat-sensitive recording material
Was. The coating amount is calculated in terms of solid content after drying, in order from the support side.
The next undercoat layer is 1.0 g / m ^TwoAnd the cyan thermosensitive recording layer is 6.
1g / m^Two, The intermediate layer is 1.0 g / m^Two, Magenta thermal recording
The layer is 7.8 g / m^Two, The intermediate layer is 1.0 g / m^Two,yellow
7.2 g / m of heat-sensitive recording layer^TwoThe light transmittance adjusting layer is 1.5
g / m^Two, And the protective layer is 1.2 g / m^TwoAnd

Example 7 A heat-sensitive recording material was produced in the same manner except that SL-TNP was used instead of ADK STAB 1500 added to the magenta heat-sensitive recording layer liquid.

Comparative Example 5 A full-color thermosensitive recording material was produced in the same manner as in Example 6, except that Adekastab 1500 was not used. (Comparative Example 6) In Example 10, the Adekastab 150
A full-color thermosensitive recording material was prepared in the same manner except that 0 was not used.

[Evaluation of Full-Color Thermosensitive Recording Material] The image light fastness of the full-color thermosensitive recording materials obtained in Examples 6 to 10 and Comparative Examples 5 to 6 was evaluated as follows. The evaluation conditions are as follows. The head used was a thermal head KST type (manufactured by Kyocera Corporation). The heat-sensitive recording material was irradiated with ultraviolet rays for 10 seconds using an ultraviolet lamp having an emission center wavelength of 420 nm and an output of 40 W to fix the yellow layer, and then applied to a thermal head so as to record an image having an azenta OD = 1.0. By adjusting the power and pulse width and printing on the thermosensitive recording material, magenta O
An image with D = 1.0 was recorded. Thereafter, the heat-sensitive recording material was irradiated and fixed for 20 seconds using an ultraviolet lamp having an emission center wavelength of 365 nm and an output of 40 W to form a magenta image.

The formed magenta image area was irradiated with light continuously for 192 hours using a super xenon weather meter (manufactured by Suga Test Instruments Co., Ltd.), and the density of the image area was measured to determine the residual ratio (%). It can be said that the higher the density (residual rate) of the image area after light irradiation, the better the image light resistance. The results of the measurement are shown in Table 2 below. Similarly, the magenta image area was continuously irradiated with light at 32,000 lux for 240 hours using a fluorescent lamp light resistance tester, and then the density of the image area was measured to determine the residual ratio (%). The results of the measurement are shown in Table 2 below.

[0188]

[Table 2]

As shown in Table 2, it is apparent that the heat-sensitive recording material of the present invention using the phosphite-based antioxidant represented by the general formula (I) has excellent image light fastness. It became.

[0190]

According to the present invention, a heat-sensitive recording material provided with a heat-sensitive recording layer containing a diazonium salt compound and a coupler compound can provide a heat-sensitive recording material having excellent image storability, particularly excellent image light fastness. .

Claims (3)

[Claims] 1. A heat-sensitive recording material comprising a support having thereon a heat-sensitive recording layer containing at least a diazonium salt compound and a coupler compound that undergoes a coupling reaction with the diazonium salt compound. A heat-sensitive recording material comprising a compound represented by the formula (I). Embedded image In the general formula (I), R ₁ , R ₂ and R ₃ each independently represent an alkyl group, an aryl group, or an acyl group. R
₁ , R ₂ and R ₃ may further have a substituent.
R ₁ and R ₂ , R ₂ and R ₃ , and R ₃ and R ₁ may form a ring with each other. 2. A general formula _{(I), R 1, R} 2 and R
_2. The heat-sensitive recording material according to claim 1, wherein at least one of the three is an aryl group. 3. The diazonium salt compound contains a 4-disubstituted amino-2-alkoxybenzenediazonium salt represented by the following general formula (II), and the coupler compound is represented by the following general formula (III). Compound and the following general formula (I
The heat-sensitive recording material according to claim 1, which contains at least one of the compounds represented by V). Embedded image In the general formula (II), R ₄ , R ₅ and R ₆ each independently represent an alkyl group, an aralkyl group or an aryl group. R ₄ and R ₅ may form a ring together with the nitrogen atom. X represents an acid anion. Embedded image In the general formula (III), Y ¹ and Y ² each independently represent a hydrogen atom, an alkyl group having 1 to 18 carbon atoms,
-21 represents an aralkyl group or an aryl group having 6 to 20 carbon atoms. Embedded image In the general formula (IV), R ₇ , R ₈ , R ₉ and R
₁₀ each independently represents a hydrogen atom, an alkyl group, an aryl group, an aralkyl group, an alkyloxy group, an aryloxy group, an alkylthio group, an arylthio group, an acyl group, an alkoxycarbonyl group, an acyloxy group, a carbamoyl group, a sulfamoyl group, and a halogen atom. Represents an atom, a cyano group or a nitro group. R ₇ , R ₈ , R ₉ , and R ₁₀ may be the same or different. R ₇ and R ₈ , R ₈ and R ₉ , and R ₉ and R ₁₀ may combine with each other to form a ring.