JP2005289009A - Recording material - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a recording material which is excellent in coloring properties, keeps the ground part colored little by exposure to light, and is excellent in raw storage properties and lightfastness. <P>SOLUTION: The recording material has on a substrate a recording layer containing a pyrazole compound expressed by general formula (1) and a diazocompound. In the general formula (1), R<SP>1</SP>denotes an aryl or aromatic heterocyclic group having two or more alkoxy or aryloxy groups different from each other as substituents and R<SP>2</SP>an alkyl group, an aryl group, the alkoxy group, the aryloxy group or acylamino group. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a recording material using a combination of at least one pyrazole compound and a diazo compound as a color forming component, particularly excellent color developability, small exposure coloration of the background portion, and image stability (light fastness of the recording portion). ), Particularly a heat-sensitive recording material.

  The diazo compound reacts with a compound called “coupler” such as a phenol derivative or a compound having an active methylene group to form an azo dye. In addition, diazo compounds have the property of decomposing by light irradiation and losing their activity. Conventionally, diazo compounds have been used for a long time as optical recording materials typified by diazocopy by utilizing this property (for example, see Non-Patent Document 1).

  In addition, diazo compounds have recently been applied to recording materials that require image fixing. As a typical example, diazo compounds and coupler compounds are heated in accordance with an image signal and reacted to form an image. A light-fixing type heat-sensitive recording material that fixes an image by light irradiation has been proposed (see, for example, Non-Patent Document 2).

  However, these recording materials have a drawback that the shell life as a recording material is short because the active diazo compound gradually decomposes by heat and loses reactivity even in a dark place. In order to remedy this drawback, a method has been proposed in which a diazo compound is encapsulated in a microcapsule and the diazo compound is isolated from a component that promotes decomposition such as water or base. By this method, the shell life of the recording material can be dramatically improved (for example, see Non-Patent Document 3).

  On the other hand, a microcapsule having a glass transition temperature higher than room temperature exhibits a substance non-permeable property at the room temperature, whereas the microcapsule exhibits a material permeability above the glass transition temperature. It can be preferably used. That is, (1) Improvement of long-term stable storage of a diazo compound by a thermosensitive recording material in which a thermoresponsive microcapsule containing a diazo compound and a thermosensitive recording layer containing a coupler compound and a base are coated on a support. (2) Colored image formation by heating and (3) Image fixing by light irradiation are possible.

In recent years, such a heat-sensitive recording material has been improved in functionality as a recording material for forming a multicolor image, and accordingly, the raw storability before recording, the image portion after recording, There is an increasing demand for improving the light fastness of the image area (see, for example, Patent Documents 1 and 2).
Further, for example, methods using an acetoacetanilide compound as a coupler for obtaining a yellow image have been proposed, but these methods have a drawback that the above performance is not sufficient (see, for example, Patent Document 3).
Japanese Patent Laid-Open No. 04-135787 Japanese Patent Laid-Open No. 04-144784 Japanese Patent Laid-Open No. 04-201483 Japan Photographic Society, “Basics of Photographic Engineering: Non-Silver Salt Photography,” Corona, 1982, 89-117, 182-201 Koji Sato, “Journal of the Institute of Image Electronics Engineers,” Volume 11, Issue 4, 1982, 290-296 Tomomasa Usami, “Journal of the Institute of Image Electronics Engineers” Vol. 26, No. 2, 1987, 115-125

  An object of the present invention is to provide a recording material, particularly a heat-sensitive recording material, which is excellent in color developability, has little exposure coloration on the background, and has excellent image stability (light fastness) in the recording area.

  In view of such a situation, the present inventor conducted intensive research and found that the above-described object can be achieved by the following recording material, thereby completing the present invention.

<1> A recording material comprising a recording layer containing a pyrazole compound represented by the following general formula (1) and a diazo compound on a support.

[In General Formula (1), R ¹ represents an aryl or aromatic heterocyclic group having two or more different alkoxy or aryloxy groups as substituents, and R ² represents an alkyl group, an aryl group, an alkoxy group, an aryloxy group A group or an acylamino group. ]

<2> The recording material according to <1>, wherein R ¹ is an aryl group.
<3> The recording material according to <1> or <2>, wherein R ² is an alkyl group.
<4> The recording material according to <1>, <2>, or <3>, wherein the pyrazole compound is a pyrazole compound represented by the following general formula (1a).

[In the general formula (1a), R ^1a represents an alkyl group or an aryl group, m represents an integer of 2 to 4, at least two of the plurality of R ^1a are different from each other, R ^2a is an alkyl group R ^3a represents a substituent, n represents an integer of 0 to 3, and OR ^1a , R ^3a or OR ^1a and R ^3a may be linked to each other to form a ring. ]

  <5> The recording material according to any one of <1> to <4>, wherein the diazo compound is a diazonium salt represented by the following general formula (2).

[In General Formula (2), R ⁴ and R ⁶ each independently represents an alkyl group, an aryl group, a heterocyclic group, or an acyl group. R ⁵ represents an alkyl group, an aryl group, an alkylsulfonyl group, an arylsulfonyl group, an acyl group, or a heterocyclic group. Y ¹ represents an oxygen atom, a sulfur atom, or an amino group, Y ² represents an oxygen atom, a sulfur atom, or a single bond, and Y ³ represents an oxygen atom, a sulfur atom, or a hydrogen atom. However, R ⁶ does not exist when Y ³ is a hydrogen atom. R ⁴ and R ⁶ may be bonded to each other to form a ring. X ⁻ represents an anion. ]

  <6> The recording material according to <5>, wherein the diazonium salt is a diazonium salt represented by the following general formula (3).

[In General Formula (3), R ⁷ and R ⁸ each independently represents an alkyl group or an aryl group, and R ⁹ represents a hydrogen atom, an alkyl group, or an aryl group. X- represents an anion. ]

  <7> The recording material according to <5>, wherein the diazonium salt is a diazonium salt represented by the following general formula (4).

[In General Formula (4), R ¹⁰ , R ¹¹ and R ¹² each independently represents an alkyl group or an aryl group. R ¹¹ and R ¹² may be bonded to each other to form a ring. X ⁻ represents an anion. ]

  <8> The recording material according to any one of <1> to <7>, wherein the diazo compound is encapsulated in a microcapsule.

  <9> The recording material according to any one of <1> to <8>, wherein the recording material is a thermosensitive recording material.

  According to the present invention, by using a specific pyrazole compound as a coupler, it is possible to provide a recording material having excellent color developability, small exposure coloration of the background portion, and excellent raw storage and light fastness.

  The recording material of the present invention has a recording layer containing a pyrazole compound represented by the general formula (1) and a diazo compound on a support. The pyrazole compound used in the present invention is more preferably one represented by the general formula (1a). The pyrazole compound represented by the following general formula (1a) corresponds to a subordinate concept of the compound represented by the following general formula (1).

Hereinafter, the pyrazole compound used in the present invention will be described, and then the recording material of the present invention will be described.
<Pyrazole compound>
As described above, the pyrazole compound used in the present invention is represented by the general formula (1). The pyrazole compound used in the present invention can be used as a coupler for obtaining a color image in a photographic material or a print material, and a precursor for synthesizing various dyes, and particularly by reaction with a diazo compound. It is suitably used for forming an azo dye.

In the general formula (1), the alkyl group represented by R ² is preferably a linear or cyclic alkyl group having 1 to 20 carbon atoms, and in particular, a linear or cyclic alkyl group having 1 to 16 carbon atoms. A linear or cyclic alkyl group having 1 to 12 carbon atoms is preferable, and for example, a methyl group, an ethyl group, an n-propyl group, an isopropyl group, an n-butyl group, an isobutyl group, an s-butyl group, an n- Amyl group, 1-ethylpropyl group, isoamyl group, neopentyl group, n-hexyl group, cyclohexyl group, n-heptyl group, cyclohexylmethyl group, n-octyl group, 2-ethylhexyl group, n-decyl group, n-dodecyl Groups are preferred.

In the general formula (1), the aryl group represented by R ² is preferably a phenyl group, a naphthyl group, an anthracenyl group, or a phenanthrenyl group, more preferably a phenyl group or a naphthyl group, and particularly preferably a phenyl group.

In the general formula (1), the R ¹ substituent or the alkoxy group represented by R ² is preferably a linear or cyclic alkoxy group having 1 to 20 carbon atoms, and in particular, a chain having 1 to 16 carbon atoms. Or a linear or cyclic alkoxy group having 1 to 12 carbon atoms is preferable, for example, a methoxy group, an ethoxy group, an n-propyloxy group, an isopropyloxy group, an n-butoxy group, or an isobutoxy group. , S-butoxy group, n-amyloxy group, 1-ethylpropyloxy group, isoamyloxy group, neopentyloxy group, n-hexyloxy group, cyclohexyloxy group, n-heptyloxy group, cyclohexylmethoxy group, n-octyl Oxy group, 2-ethylhexyloxy group, n-decyloxy group, n-dodecyloxy group are preferred. That's right.

In the general formula (1), the substituent for R ¹ or the aryloxy group represented by R ² is preferably a phenoxy group, a naphthyloxy group, an anthracenyloxy group, or a phenanthrenyloxy group, among which a phenoxy group And a naphthyloxy group are preferable, and a phenoxy group is particularly preferable.

In the general formula (1), the acylamino group represented by R ² is preferably a chain or cyclic acylamino group having 2 to 21 carbon atoms, and in particular, a chain or cyclic acylamino group having 2 to 17 carbon atoms. Preferred is a chain or cyclic acylamino group having 2 to 13 carbon atoms, such as acetylamino group, propionylamino group, n-butyrylamino group, isobutyrylamino group, pivaloylamino group, isovaleroylamino group, cyclohexanecarbonyl. Amino group, n-lauroylamino group, n-myristoylamino group, n-palmitoylamino group, n-stearoylamino group, benzoylamino group, 1-naphthoylamino group, 2-naphthoylamino group, 2-furoylamino group, 2-thenoylamino group, pyridine-2-carbonylamino It is preferred.

In the general formula (1), the hetero atom contained in the aromatic heterocyclic group represented by R ¹ is preferably nitrogen, oxygen, sulfur, selenium, tellurium, or phosphorus atom, and particularly preferably nitrogen, oxygen, or sulfur atom, Nitrogen and oxygen atoms are particularly preferable. The aromatic heterocyclic group represented by R ¹ is preferably a saturated or unsaturated heterocyclic group having 1 to 10 carbon atoms, more preferably a saturated or unsaturated heterocyclic group having 2 to 8 carbon atoms. In particular, an unsaturated heterocycle having 2 to 7 carbon atoms is preferable, for example, 2-pyridyl group, 3-pyridyl group, 4-pyridyl group, 3-pyridazinyl group, 2-pyrimidinyl group, 4-pyrimidinyl group, 2-pyrazinyl group. Group, s-triazinyl group, 2-indolyl group, 3-indolyl group, 2-quinolinyl group, 1-isoquinolinyl group, 2-furanyl group, 2-pyrrolyl group, 3-pyrazolyl group, 2-imidazolyl group, 2-oxazolyl group Group, 2-thiazolyl group, 1,2,4-triazol-3-yl group, 2-benzimidazolyl group, 2-benzoxazolyl group, 2-benzothiazolyl group are preferable. Arbitrariness.

In the general formula (1), R ¹ represents an aryl or aromatic heterocyclic group having two or more different alkoxy or aryloxy groups as substituents. In this case, any of the plurality of alkoxy or aryloxy groups Are alkoxy groups which may be different from each other, either may be an aryloxy group and may be different from each other, one may be an alkoxy group and the other may be an aryloxy group.
In the general formula (1), when the substituents (alkoxy or aryloxy group) of R ¹ are different from each other, each of the plurality of substituents can have a separate function, and as a result, a plurality of performances are satisfied at the same time. Can be provided.
The substituent of R ¹ (alkoxy or aryloxy group) may further have a substituent. However, since each substituent bears different performance, it is preferable that the difference between the substituents is clear. It is preferable that they are different from each other in the state of substitution. However, when the number of R ¹ substituents (alkoxy or aryloxy groups) is 3 or more, two of them may be different from each other, or three or more may be different from each other, but two of them are different from each other. The object of the present invention can be achieved sufficiently.

In the general formula (1), R ¹ and R ² may further have a substituent. Examples of such a substituent include an alkyl group having 1 to 20 carbon atoms and an aryl group having 6 to 14 carbon atoms. A heterocyclic group having 1 to 10 carbon atoms, a halogen atom, an alkoxy group having 1 to 20 carbon atoms, a sulfenyl group having 1 to 20 carbon atoms, an aryloxy group having 6 to 14 carbon atoms, and the number of carbon atoms An acylsulfonyl group having 2 to 21 carbon atoms, an alkylsulfonyl group having 1 to 20 carbon atoms, an arylsulfonyl group having 6 to 14 carbon atoms, an acyloxy group having 2 to 21 carbon atoms, an acylamino group having 2 to 21 carbon atoms, carbon An alkoxycarbonyl group having 2 to 21 atoms, an aryloxycarbonyl group having 7 to 15 carbon atoms, a carbamoyl group having 1 to 21 carbon atoms, a sulfamoyl group having 0 to 20 carbon atoms, a hydroxy group; Sil group, cyano group, carboxy group, sulfo group, and nitro group are preferable. Among them, alkyl group having 1 to 16 carbon atoms, aryl group having 6 to 10 carbon atoms, heterocyclic group having 2 to 8 carbon atoms, halogen Atom, alkoxy group having 1 to 16 carbon atoms, sulfenyl group having 1 to 16 carbon atoms, aryloxy group having 6 to 10 carbon atoms, acyl group having 2 to 17 carbon atoms, 1 to 16 carbon atoms An alkylsulfonyl group, an arylsulfonyl group having 6 to 10 carbon atoms, an acyloxy group having 2 to 17 carbon atoms, an acylamino group having 2 to 17 carbon atoms, an alkoxycarbonyl group having 2 to 17 carbon atoms, and the number of carbon atoms Preferred are an aryloxycarbonyl group having 7 to 11 carbon atoms, a carbamoyl group having 1 to 17 carbon atoms, a sulfamoyl group having 0 to 16 carbon atoms, a hydroxyl group, and a cyano group. In particular, an alkyl group having 1 to 12 carbon atoms (for example, methyl group, ethyl group, n-propyl group, isopropyl group, n-butyl group, isobutyl group, s-butyl group, n-amyl group, 1-ethyl group) Propyl group, isoamyl group, neopentyl group, n-hexyl group, cyclohexyl group, n-heptyl group, cyclohexylmethyl group, n-octyl group, 2-ethylhexyl group, n-decyl group, n-dodecyl group), phenyl, chlorine Atom (for example, chlorine atom, bromine atom), C1-C12 alkoxy group (for example, methoxy group, ethoxy group, n-propoxy group, isopropoxy group, n-butoxy group, isobutoxy group, s-butoxy group) N-amyloxy group, 1-ethylpropoxy group, isoamyloxy group, neopentyloxy group, n-hexyloxy group, Cyclohexyloxy group, n-heptyloxy group, cyclohexylmethoxy group, n-octyloxy group, 2-ethylhexyloxy group, n-decyloxy group, n-dodecyloxy group), sulfenyl group having 1 to 12 carbon atoms ( For example, methylsulfenyl group, ethylsulfenyl group, n-propylsulfenyl group, isopropylsulfenyl group, n-butylsulfenyl group, isobutylsulfenyl group, s-butylsulfenyl group, n-amylsulfenyl group, 1-ethylpropylsulfenyl group, isoamylsulfenyl group, neopentylsulfenyl group, n-hexylsulfenyl group, cyclohexylsulfenyl group, n-heptylsulfenyl group, cyclohexylmethylsulfenyl group, n-octylsulfenyl group , 2-ethylhexyl Sulfenyl group, n-decylsulfenyl group, n-dodecylsulfenyl group), acyl group having 2 to 13 carbon atoms (for example, acetyl group, propionyl group, n-butyryl group, isobutyryl group, pivaloyl group, isovaroyl group) , Cyclohexanecarbonyl group, n-lauroyl group, n-myristoyl group, n-palmitoyl group, n-stearoyl group, benzoyl group, 1-naphthoyl group, 2-naphthoyl group, 2-furoyl group, 2-thenoyl group, pyridine- 2-carbonyl group), alkylsulfonyl group having 1 to 12 carbon atoms (for example, methylsulfonyl group, ethylsulfonyl group, n-propylsulfonyl group, isopropylsulfonyl group, n-butylsulfonyl group, isobutylsulfonyl group, s-butyl) Sulfonyl group, n-amylsulfonyl group, 1-ethyl Propylsulfonyl group, isoamylsulfonyl group, neopentylsulfonyl group, n-hexylsulfonyl group, cyclohexylsulfonyl group, n-heptylsulfonyl group, cyclohexylmethylsulfonyl group, n-octylsulfonyl group, 2-ethylhexylsulfonyl group, n-decylsulfonyl Group, n-dodecylsulfonyl group), an acyloxy group having 2 to 13 carbon atoms (for example, acetoxy group, propionyloxy group, n-butyryloxy group, isobutyroxy group, pivaloyloxy group, isovaroyloxy group, cyclohexanecarbonyloxy group, n-lauroyloxy group, n-myristoyloxy group, n-palmitoyloxy group, n-stearoyloxy group, benzoyloxy group, 1-naphthoyloxy group, 2-naphthoyloxy group, 2 Furoyloxy group, 2-thenoyloxy group, pyridine-2-carbonyloxy group), acylamino group having 2 to 13 carbon atoms (for example, acetylamino group, N-methylacetylamino group, propionylamino group, n-butyrylamino group, iso Butyrylamino group, pivaloylamino group, isovaleroylamino group, cyclohexanecarbonylamino group, n-lauroylamino group, n-myristoylamino group, n-palmitoylamino group, n-stearoylamino group, benzoylamino group, 1-naphtho Ylamino group, 2-naphthoylamino group, 2-furoylamino group, 2-thenoylamino group, pyridine-2-carbonylamino), phenylsulfonyl group, alkoxycarbonyl group having 2 to 13 carbon atoms (for example, methoxycarbonyl group, Ethoxycal Bonyl group, n-propoxycarbonyl group, isopropoxycarbonyl group, n-butoxycarbonyl group, isobutoxycarbonyl group, s-butoxycarbonyl group, n-amyloxycarbonyl group, 1-ethylpropoxycarbonyl group, isoamyloxycarbonyl group, Neopentyloxycarbonyl group, n-hexyloxycarbonyl group, cyclohexyloxycarbonyl group, n-heptyloxycarbonyl group, cyclohexylmethoxycarbonyl group, n-octyloxycarbonyl group, 2-ethylhexyloxycarbonyl group, n-decyloxycarbonyl group N-dodecyloxycarbonyl group), a carbamoyl group having 1 to 13 carbon atoms (for example, methylcarbamoyl group, ethylcarbamoyl group, n-propylcarbamoyl group, isopropyl) Rubamoyl group, n-butylcarbamoyl group, n-butylcarbamoyl group, s-butylcarbamoyl group, i-butylcarbamoyl group, t-butylcarbamoyl group, n-amylcarbamoyl group, isoamylcarbamoyl group, phenylcarbamoyl group, n-octyl Carbamoyl group, 2-ethylhexylcarbamoyl group, cyclohexylcarbamoyl group), sulfamoyl group having 0 to 12 carbon atoms (for example, methylsulfamoyl group, ethylsulfamoyl group, n-propylsulfamoyl group, isopropylsulfamoyl group) Group, n-butylsulfamoyl group, n-butylsulfamoyl group, s-butylsulfamoyl group, i-butylsulfamoyl group, t-butylsulfamoyl group, n-amylsulfamoyl group, Isoamylsulfamoyl group, A phenylsulfamoyl group, an n-octylsulfamoyl group, a 2-ethylhexylsulfamoyl group, and a cyclohexylsulfamoyl group). When a plurality of substituents are present, the plurality of substituents are bonded to each other. A ring may be formed, and in that case, the number of ring members is preferably 4 to 8, more preferably 5 to 7, and particularly preferably 5 or 6.

The pyrazole compound represented by the general formula (1) is more preferably a compound represented by the following general formula (1a).
In the general formula (1a), preferred ranges and specific examples of the alkyl represented by R ^1a or R ^2a are the same as the alkyl group represented by R ² in the general formula (1).
In the general formula (1a), the preferred range and specific examples of the aryl group represented by R ^1a are the same as the aryl group represented by R ² in the general formula (1).
In the general formula (1a), the integer represented by m is preferably 2 or 3, and more preferably 2.
In the general formula (1a), the integer represented by n is preferably 0 to 2, more preferably 0 or 1, and particularly preferably 0.
In the general formula (1a), the substituent represented by R ^3a is the same as those exemplified as the substituents for R ¹ and R ² in the general formula (1).
In the general formula (1a), R ^1a , R ^2a and R ^3a may further have a substituent, and examples of the substituent include those listed as the substituents for R ¹ and R ² in the general formula (1). It is the same.

In the general formula (1a), a plurality of OR ^1a represent two different alkoxy or aryloxy groups, and at this time, the plurality of alkoxy or aryloxy groups are all alkoxy groups and are different from each other. Either may be an aryloxy group and may be different from each other, or one may be an alkoxy group and the other may be an aryl group, but both are alkoxy groups and are different from each other. It is preferable that two of the plurality of OR ^1a have a substitution position at a para position relative to each other.
OR ^1a may further have a substituent, but since each OR ^1a is responsible for different performance, it is preferable that the difference between OR ^1a is clear, and therefore different from each other in an unsubstituted state. Is preferred. However, when the number of OR ^1a is 3, two of them may be different from each other, or the three may be different from each other. However, the object of the present invention can be sufficiently achieved by having two of them different from each other.
In the general formula (1a), R ^2a is preferably a tertiary or secondary alkyl group, more preferably a tertiary alkyl group, and particularly preferably a t-butyl group.

  The pyrazole compounds used in the present invention are described in, for example, Journal of Medicinal Chemistry, Vol. 45, no. 14, 2994 (2002).

  Specific examples of the pyrazole compound represented by the general formula (1) are shown below, but the compound used for the recording material of the present invention is not limited thereto.

<Recording material>
Next, the recording material of the present invention will be described. The recording material of the present invention has, on a support, at least one recording layer containing a diazo compound and a pyrazole compound represented by the general formula (1) as a coupler that develops color by reacting with the diazo compound. It is characterized by. As the recording material of the present invention, a heat-sensitive recording material having a heat-sensitive recording layer having a color-developing method, a pressure-sensitive recording material having a pressure-sensitive recording layer having a color-developing method, and a heat forming a latent image by light. Examples thereof include a heat-sensitive photothermographic recording material.

<Recording layer>
The recording layer in the present invention contains at least a pyrazole compound represented by the general formula (1) and a diazo compound, and the diazo compound is preferably contained in a microcapsule. Moreover, you may contain various additives, such as an organic base and a coloring aid, as needed.

  In the recording layer of the present invention, the total content of the coupler containing the pyrazole compound represented by the general formula (1) is preferably 0.2 to 8 mol, more preferably 0.5 to 4 mol, relative to 1 mol of the diazo compound. preferable. When the total coupler content is less than 0.2 mol per 1 mol of diazo compound, sufficient color development may not be obtained, and when it exceeds 8 mol per 1 mol of diazo compound, the coating suitability deteriorates. There is.

  Further, in the present invention, a known coupler that forms a dye by coupling with a diazo compound in a basic atmosphere as necessary for the purpose of adjusting the hue together with the pyrazole compound represented by the general formula (1) in the present invention. Can also be used in combination. When the pyrazole compound represented by the general formula (1) and a known coupler are used in combination, 50% by mass or more of all the couplers contained in the recording layer is the pyrazole compound represented by the general formula (1). It is preferably 70% by mass or more.

  Examples of the known couplers include so-called active methylene compounds having a methylene group next to a carbonyl group, phenol derivatives, naphthol derivatives, and the like.

  Specific examples of the known coupler include resorcin, phloroglucin, sodium 2,3-dihydroxynaphthalene-6-sulfonate, 1-hydroxy-2-naphthoic acid morpholinopropylamide, 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, benzoyl Acetonilide, 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 ヅ amide} phenol 2,4-bis- (benzoylacetamino) toluene, 1,3-bis- (pivaloylacetaminomethyl) benzene and the like.

(Diazo compound)
The diazo compound used in the recording layer in the invention is not particularly limited, but it is preferable to use a diazonium salt represented by the following general formula (2).

In general formula (2), R ⁴ and R ⁶ each independently represents an alkyl group, an aryl group, a heterocyclic group, or an acyl group. R ⁵ represents an alkyl group, an aryl group, an alkylsulfonyl group, an arylsulfonyl group, an acyl group, or a heterocyclic group. Y ¹ represents an oxygen atom, a sulfur atom, or an amino group, Y ² represents an oxygen atom, a sulfur atom, or a single bond, and Y ³ represents an oxygen atom, a sulfur atom, or a hydrogen atom. However, R ⁶ does not exist when Y ³ is a hydrogen atom. R ⁴ and R ⁶ may be bonded to each other to form a ring. X ⁻ represents an anion.

In the general formula (2), R ⁴ and R ⁶ are preferably an alkyl group having 1 to 30 carbon atoms, an aryl group having 6 to 30 carbon atoms, and an acyl group having 2 to 20 carbon atoms.
The alkyl group represented by R ⁴ or R ⁶ may further have a substituent. Examples of the substituent include an aryl group, a halogen atom, an alkoxy group, an aryloxy group, an alkoxycarbonyl group, an acyloxy group, An acylamino group, carbamoyl group, cyano group, carboxylic acid group, sulfonic acid group or heterocyclic group is preferred.

As the alkyl group represented by R ⁴ and R ⁶ , a methyl group, an ethyl group, a normal propyl group, an isopropyl group, a normal butyl group, an isobutyl group, a pentyl group, a 3-pentyl group, a cyclopentyl group, a hexyl group, a cyclohexyl group, and the like. Group, heptyl group, octyl group, 2-ethylhexyl group, decyl group, dodecyl group, octadecyl group, 2-hydroxyethyl group, 2-benzoyloxyethyl group, 2- (4-butoxyphenoxy) ethyl group, benzyl group, allyl group Group, methoxyethyl group, ethoxyethyl, dibutylaminocarbonylmethyl group are preferred.

The aryl group represented by R ⁴ or R ⁶ may further have a substituent. Examples of the substituent include an aryl group, a halogen atom, an alkoxy group, an aryloxy group, an alkoxycarbonyl group, and an acyloxy group. An acylamino group, a carbamoyl group, a cyano group, a carboxylic acid group, a sulfonic acid group or a heterocyclic group is preferred.
As the aryl group represented by R ⁴ and R ⁶ , a phenyl group, a 4-methoxyphenyl group, a 4-chlorophenyl group, a 4-methylphenyl group, a 4-butoxyphenyl group, and a naphthyl group are particularly preferable.

When R ⁴ or R ⁶ is a heterocyclic group, the heterocyclic ring preferably has nitrogen, oxygen, or sulfur as a hetero atom, and any of saturated, unsaturated, monocyclic, and condensed rings Good. Specific examples include furyl, thienyl, oxazolyl, azozolyl, imidazolyl, pyrazolyl, pyridyl, pyrimidyl, morpholinyl, piperazinyl, indolyl, isoindolyl and the like. Furthermore, these heterocyclic groups may have a substituent. Examples of the substituent include the same ones as described above for the alkyl group.

The acyl group represented by R ⁴ or R ⁶ may be aliphatic, aromatic, or heterocyclic, and may further have a substituent. As the substituent, an alkoxy group, an aryloxy group, and a halogen atom are preferable.
As the acyl group represented by R ⁴ and R ⁶ , an acetyl group, a propanoyl group, a hexanoyl group, a benzoyl group and the like are particularly preferable.

R ⁴ and R ⁶ may be bonded to each other to form a ring. Examples of the ring in which R ⁴ and R ⁶ are bonded include a thiazole ring, an oxazole ring, and an imidazole ring, and these may further have a substituent. Examples of the substituent include the same ones as described above for the alkyl group.

In General Formula (2), R ⁵ is preferably an alkyl group having 1 to 20 carbon atoms, an aryl group having 6 to 20 carbon atoms, or an acyl group having 2 to 20 carbon atoms.
Examples of the alkyl group, aryl group, heterocyclic group, and acyl group for R ⁵ include the same alkyl groups, aryl groups, heterocyclic groups, and acyl groups as those described above for R ⁴ and R ⁶ .

The alkylsulfonyl group represented by R ⁵ may further have a substituent. Examples of the substituent include an aryl group, a halogen atom, an alkoxy group, an aryloxy group, an alkoxycarbonyl group, an acyloxy group, and an acylamino group. , A carbamoyl group, a cyano group, a carboxylic acid group, a sulfonic acid group or a heterocyclic group is preferred.

Examples of the alkylsulfonyl group represented by R ⁵ include a methylsulfonyl group, an ethylsulfonyl group, a butylsulfonyl group, a hexylsulfonyl group, a decylsulfonyl group, a benzylsulfonyl group, and a methoxybutylsulfonyl group.

The arylsulfonyl group represented by R ⁵ may further have a substituent. Examples of the substituent include an aryl group, a halogen atom, an alkoxy group, an aryloxy group, an alkoxycarbonyl group, an acyloxy group, and an acylamino group. , A carbamoyl group, a cyano group, a carboxylic acid group, a sulfonic acid group or a heterocyclic group is preferred.

Examples of the arylsulfonyl group represented by R ⁵ include a phenylsulfonyl group, a naphthylsulfonyl group, a 4-chlorosulfonyl group, and a 4-methylsulfonyl group.

In the general formula (2), Y ¹ is preferably a sulfur atom or an amino group, and when Y ¹ is an amino group, it may further have a substituent. Examples of the substituent include an alkyl group and an aryl group.
Y ¹ and R ⁴ may form a ring. Examples of the ring formed by Y ¹ and R ⁴ include pyrrolidinyl, piperidinyl, piperazinyl, indolyl group, and the like, and these may further have a substituent. Examples of the substituent include the same ones as described above for the alkyl group.

In the general formula (2), Y ² is preferably a sulfur atom or an oxygen atom. Similarly, Y ³ is preferably a sulfur atom or an oxygen atom.

Examples of the anion represented by X ⁻ in the general formula (2) include inorganic anions and organic anions. As the inorganic anion, hexafluorophosphate ion, borohydrofluoric acid ion, chloride ion, and sulfate ion are preferable, and hexafluorophosphate ion and borohydrofluoric acid ion are particularly preferable. As the organic anion, polyfluoroalkylcarboxylate ions, polyfluoroalkylsulfonate ions, tetraphenylborate ions, aromatic carboxylate ions, and aromatic sulfonate ions are particularly preferable.

  The diazonium salt represented by the general formula (2) is preferably a diazonium salt represented by the following general formula (3) or general formula (4).

[In General Formula (3), R ⁷ and R ⁸ each independently represents an alkyl group or an aryl group, and R ⁹ represents a hydrogen atom, an alkyl group, or an aryl group. X- represents an anion. ]

[In General Formula (4), R ¹⁰ , R ¹¹ and R ¹² each independently represents an alkyl group or an aryl group. R ¹¹ and R ¹² may be bonded to each other to form a ring. X- represents an anion. ]

As R < ⁷ >, R < ⁸ > and R < ⁹ > in General formula (3), a C1-C20 alkyl group and a C6-C30 aryl group are preferable.
The alkyl group represented by R ⁷ , R ⁸ and R ⁹ may further have a substituent. Examples of the substituent include an aryl group, a halogen atom, an alkoxy group, an aryloxy group, and an alkoxycarbonyl group. An acyloxy group, an acylamino group, a carbamoyl group, a cyano group, a carboxylic acid group, a sulfonic acid group or a heterocyclic group is preferred.

As the alkyl group represented by R ⁷ , R ⁸ and R ⁹ , methyl group, ethyl group, normal propyl group, isopropyl group, normal butyl group, isobutyl group, pentyl group, cyclopentyl group, hexyl group, cyclohexyl group, Heptyl, octyl, 2-ethylhexyl, decyl, dodecyl, octadecyl, 2-hydroxyethyl, 2-benzoyloxyethyl, 2- (4-butoxyphenoxy) ethyl, benzyl, allyl, A methoxyethyl group, an ethoxyethyl group, and a dibutylaminocarbonylmethyl group are preferred.

In the general formula (3), the aryl group represented by R ⁷ , R ⁸ and R ⁹ may further have a substituent. Examples of the substituent include an aryl group, a halogen atom, an alkoxy group, An aryloxy group, alkoxycarbonyl group, acyloxy group, acylamino group, carbamoyl group, cyano group, carboxylic acid group, sulfonic acid group or heterocyclic group is preferred.
As the aryl group represented by R ⁷ , R ⁸ and R ⁹ , a phenyl group, a 4-chlorophenyl group, a 4-methylphenyl group, and a 4-butoxyphenyl group are particularly preferable.

  X <-> in the general formula (3) has the same meaning as X <-> in the general formula (2), and examples thereof include the same.

Preferred examples of the alkyl group represented by R ¹⁰ , R ¹¹ and R ¹² in formula (4), the aryl group, and X ⁻ are alkyl groups represented by R ^{7 to} R ⁹ in formula (3). , Aryl group, and the same thing as X-. R ¹¹ and R ¹² may be bonded to each other to form a ring, and examples of the ring formed by R ¹¹ and R ¹² include a morpholine ring, a piperidine ring, and a pyrrolidine ring.

  Specific examples of the diazonium salt compounds represented by the general formulas (2) to (4) (illustrated compounds (D-1) to (D-92)) are shown below, but the present invention is not limited thereto. .

~ Diazonium salt represented by the general formula (2) ~

~ Diazonium salt represented by the general formula (3) ~

~ Diazonium salt represented by general formula (4) ~

  The diazonium salts represented by the general formulas (2) to (4) may be used alone or in combination of two or more. Furthermore, depending on various purposes such as hue adjustment, the diazonium salt represented by the general formulas (2) to (4) and a known diazo compound may be used in combination. When the diazonium salt represented by the general formulas (2) to (4) and a known diazo compound are used in combination, the diazonium salt represented by the general formulas (2) to (4) is contained in the recording layer. It is preferable that it is 50 mass% or more of a diazo compound, and it is preferable that it is 80 mass% or more. The diazonium salt used in the present invention is preferably a diazonium salt represented by the general formula (3) or (4), and particularly preferably a diazonium salt represented by the general formula (3).

  Examples of the known diazo compounds include 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-Toluyl mercapto-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-ethyl Sanoylpiperidino) -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 preferable.

  In the recording material of the present invention, in order to improve the raw storage stability before use of the recording material, it is preferable to encapsulate the diazo compound in a microcapsule as described in detail later. Since the diazo compound is used by being dissolved in an appropriate solvent, the diazo compound preferably has an appropriate solubility in these solvents and low water solubility. Specifically, it has a solubility of 5% or more with respect to the organic solvent to be used, and the solubility in water is preferably 1% or less.

In the recording material of the present invention, the diazo compound is preferably contained in the recording layer in the range of 0.02 to 3 g / m ² , and particularly in the range of 0.1 to ² g / m ² from the viewpoint of color density. It is preferable to contain.

(Microcapsule)
In the recording material of the present invention, it is preferable to encapsulate a diazo compound in a microcapsule in order to improve the raw storage stability before use.
The microcapsules used in this case are prepared by dissolving a solution of a diazonium salt in a non-aqueous solvent having a boiling point of 40 to 95 ° C. at normal pressure and the same or different compound that reacts with each other to form a polymer substance. After emulsifying and dispersing in the hydrophilic protective colloid solution, the temperature of the solution is raised while reducing the pressure of the reaction vessel to move the wall-forming substance to the surface of the oil droplets while distilling off the solvent. It is produced by forming a wall film by advancing a polymer formation reaction by polycondensation.

  In the recording material of the present invention, it is particularly preferable to use microcapsules which are substantially free of a solvent, which will be described later, from the viewpoint of obtaining a good shelf life. The polymer material forming the microcapsule wall is preferably at least one selected from polyurethane and polyurea.

A method for producing the diazonium salt-containing microcapsules (polyurea / polyurethane wall) in the recording material of the present invention will be described below.
First, the diazo compound is dissolved in a hydrophobic organic solvent that becomes the core of the capsule. As the hydrophobic organic solvent used in this case, an organic solvent having a boiling point of 100 ° C. to 300 ° C. is preferable. Aromatic hydrocarbons, halogenated hydrocarbons, carboxylic acid esters, phosphate esters, sulfate esters, Examples include sulfonic acid esters, ketones, and ethers. Specific examples of the organic solvent include alkyl naphthalene, alkyl diphenyl ethane, alkyl diphenyl methane, alkyl biphenyl, chlorinated paraffin, trixyl phosphate, tricresyl phosphate, maleic acid dioctyl ester, adipic acid dibutyl ester and the like. These may be used individually by 1 type and may use 2 or more types together.
Moreover, when the solubility of the diazo compound to be encapsulated in the organic solvent is poor, a low-boiling solvent having high solubility in the diazo compound can be used in combination. Specific examples of the low boiling point solvent include ethyl acetate, butyl acetate, methylene chloride, tetrahydrofuran, and acetone. In addition, a polyvalent isocyanate is further added as a wall material to the hydrophobic organic solvent that becomes the core of the microcapsule (oil phase).

  On the other hand, as the aqueous phase, an aqueous solution in which a water-soluble polymer such as polyvinyl alcohol or gelatin is dissolved is prepared, and then the oil phase is added and emulsified and dispersed by means such as a homogenizer. At this time, the water-soluble polymer acts as a stabilizer for emulsion dispersion. In order to carry out emulsification and dispersion more stably, a surfactant may be added to at least one of the oil phase and the aqueous phase.

  The amount of polyvalent isocyanate used is determined so that the average particle size of the microcapsules is 0.3 to 12 μm and the wall thickness is 0.01 to 0.3 μm. The dispersed particle size is generally about 0.2 to 10 μm. In the emulsified dispersion, a polyisocyanate polymerization reaction occurs at the interface between the oil phase and the aqueous phase to form polyurea walls.

  If a polyol is added to the aqueous phase, the polyvalent isocyanate and the polyol can react to form a polyurethane wall. In order to increase the reaction rate, it is preferable to keep the reaction temperature high or to add an appropriate polymerization catalyst. The polyisocyanate, polyol, reaction catalyst, polyamine for forming a part of the wall agent, etc. are well known in the book (Keiji Iwata, Polyurethane Handbook, Nikkan Kogyo Shimbun (1987)).

  The polyvalent isocyanate compound used as the raw material for the microcapsule wall is preferably a compound having a trifunctional or higher functional isocyanate group, but a bifunctional isocyanate compound may be used in combination. Specifically, xylene diisocyanate and its hydrogenated product, hexamethylene diisocyanate, tolylene diisocyanate and its hydrogenated product, and diisocyanates such as isophorone diisocyanate are used as the main raw materials, and these dimers or trimers (burette or isosinurate). In addition, polyfunctional adducts with polyols such as trimethylolpropane, formalin condensates of benzene isocyanate, and the like.

  Furthermore, polyol or polyamine can be added to a hydrophobic solvent serving as a core or a water-soluble polymer solution serving as a dispersion medium, and used as one of raw materials for a microcapsule wall. Specific examples of these polyols or polyamines include propylene glycol, glycerin, trimethylolpropane, triethanolamine, sorbitol, hexamethylenediamine and the like. When a polyol is added, a polyurethane wall is formed.

  The water-soluble polymer used in the water-soluble polymer aqueous solution for dispersing the oil phase of the capsule thus prepared is preferably a water-soluble polymer having a water solubility of 5 or more at the temperature to be emulsified. As polyvinyl alcohol and its modified products, polyacrylic acid amide and its derivatives, ethylene-vinyl acetate copolymer, styrene-maleic anhydride copolymer, ethylene-maleic anhydride copolymer, isobutylene-maleic anhydride copolymer. Examples include polymers, polyvinylpyrrolidone, ethylene-acrylic acid copolymers, vinyl acetate-acrylic acid copolymers, carboxymethylcellulose, methylcellulose, casein, gelatin, starch derivatives, arabic gum, and sodium alginate.

  These water-soluble polymers preferably have no or low reactivity with isocyanate compounds. For example, those having a reactive amino group in the molecular chain, such as gelatin, can be modified by modification beforehand. It is necessary to eliminate this. Moreover, when adding surfactant, it is preferable that the addition amount of surfactant is 0.1%-5% with respect to the mass of an oil phase, especially 0.5%-2%.

  For emulsification, a known emulsification apparatus such as a homogenizer, a manton gorey, an ultrasonic disperser, or a teddy mill can be used. After emulsification, the emulsion is heated to 30 to 70 ° C. in order to promote the capsule wall formation reaction. Further, during the reaction, in order to prevent aggregation between the capsules, it is necessary to add water to reduce the collision probability between the capsules or to perform sufficient stirring.

  Further, a dispersing agent for preventing aggregation may be added again during the reaction. As the polymerization reaction proceeds, the generation of carbon dioxide gas is observed, and its end can be regarded as the approximate end point of the capsule wall formation reaction. Usually, the target diazonium salt-containing microcapsules can be obtained by reacting for several hours.

(Organic base)
In the recording material of the present invention, an organic base may be added for the purpose of promoting the coupling reaction between the diazo compound and the coupler.
These organic bases can be used alone or in combination of two or more. Examples of the basic substance include nitrogen-containing compounds such as tertiary amines, piperidines, piperazines, amidines, formamidines, pyridines, guanidines and morpholines.

  Among these, in particular, 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'-bis [3- (β- Naphthoxy) -2-hydroxypropyl] piperazine, N-3- (β-naphthoxy) -2-hydroxypropyl-N′-methylpiperazine, 1,4-bis {[3- (N-methylpiperazino) -2-hydroxy] Piperazines such as propyloxy} benzene, N- [3- (β-naphthoxy) -2-hydroxy] propylmorpholine, 1,4-bis [(3- Morpholines such as morpholino-2-hydroxy) propyloxy] benzene, 1,3-bis [(3-morpholino-2-hydroxy) propyloxy] benzene, N- (3-phenoxy-2-hydroxypropyl) piperidine, N -Piperidines such as dodecylpiperidine, guanidines such as triphenylguanidine, tricyclohexylguanidine, dicyclohexylphenylguanidine and the like are preferable.

  In the recording material of the present invention, the amount of the organic base used relative to 1 part by mass of the diazo compound is preferably 0.1 to 30 parts by mass.

(Coloring aid)
In the present invention, in addition to the organic base described above, a coloring aid can be added for the purpose of promoting the coloring reaction. The color assistant is a substance that increases the color density during heat recording or lowers the minimum color development temperature, lowers the melting point of couplers, basic substances, diazo compounds, etc., or softens the capsule wall. This is intended to create a situation in which diazo compounds, basic substances, couplers, etc. are likely to react by the action of lowering the amount of water.

  As the color developing aid used in the recording material of the present invention, for example, a phenol derivative, a naphthol derivative, an alkoxy-substituted benzene, an alkoxy-substituted naphthalene, a hydroxy, and the like in the photosensitive layer so that rapid and complete thermal development is performed with low energy. Compounds, amide compounds, sulfonamide compounds and the like can be added. These compounds are considered to reduce the melting point of couplers and basic substances, or to improve the heat permeability of the microcapsule wall, thereby enabling a high color density.

  The coloring aid used in the recording material of the present invention may be a heat-meltable substance. The heat-melting substance is a substance having a melting point of 50 ° C. to 150 ° C. that is solid at normal temperature and melts by heating, and is a substance that dissolves a diazo compound, a coupler, a basic substance, or the like. Specific examples of these compounds include carboxylic acid amides, N-substituted carboxylic acid amides, ketone compounds, urea compounds, esters and the like.

(Other additives)
In the recording material of the present invention, the following known antioxidants are used for the purpose of improving fastness to light and heat of a thermochromic image or reducing yellowing due to light in an unprinted portion after fixing. Is preferably used.

  Examples of the antioxidant include, for example, European Patent Nos. 223739, 309401, 309402, 310551, 310552, 455416, German Patent No. No. 3435443, JP-A-54-48535, JP-A-62-262047, JP-A-63-113536, JP-A-63-163351, JP-A-2-262654, JP-A-2-71262, JP-A-3-121449, JP-A-5-61166, JP-A-5-119449, US Pat. No. 4,814,262, US Pat. No. 4,980,275 and the like.

  Furthermore, it is also effective to use various known additives already used in heat-sensitive recording materials and pressure-sensitive recording materials. Specific examples of these antioxidants include JP-A-60-107384, JP-A-60-107383, JP-A-60-125470, JP-A-60-125471, JP-A-60-125472, and JP-A-60. -287485, 60-287486, 60-287487, 60-287488, 61-160287, 61-185483, 61-2111079, 62- 146678, 62-146680, 62-146679, 62-28285, 63-051174, 63-89877, 63-88380, 63-088381 Gazette, 63-203372 gazette, 63-224989 gazette, 63-251 gazette. No. 82, No. 63-267594, No. 63-182484, JP-A-01-239282, No. 04-29185, No. 04-291684, No. 05-188687, No. 05- 188686, 05-110490, 05-1108437, 05-170361, Japanese Patent Publication No. 48-043294, 48-033212, and the like. it can.

  Specifically, 6-ethoxy-1-phenyl-2,2,4-trimethyl-1,2-dihydroquinoline, 6-ethoxy-1-octyl-2,2,4-trimethyl-1,2-dihydroquinoline 6-ethoxy-1-phenyl-2,2,4-trimethyl-1,2,3,4-tetrahydroquinoline, 6-ethoxy-1-octyl-2,2,4-trimethyl-1,2,3 4-tetrahydroquinoline, nickel cyclohexaneate, 2,2-bis-4-hydroxyphenylpropane, 1,1-bis-4-hydroxyphenyl-2-ethylhexane, 2-methyl-4-methoxy-diphenylamine, 1-methyl -2-phenylindole and the like.

  The addition amount of these antioxidants is preferably 0.05 to 100 parts by mass, particularly preferably 0.2 to 30 parts by mass with respect to 1 part by mass of the diazo compound. The above-mentioned known antioxidants can be used in a microcapsule together with a diazo compound, or they can be used as a solid dispersion or with a suitable emulsification aid together with a coupling component, a basic substance, or other coloring aid. It can be used in the form of an emulsion or in both forms. Of course, one or more antioxidants can be used in combination. Further, a protective layer can be provided on the recording layer, and the protective layer can be added or exist.

  These antioxidants need not be added to the same layer. When these antioxidants are used in combination, they are structurally classified as anilines, alkoxybenzenes, hindered phenols, hindered amines, hydroquinone derivatives, phosphorus compounds, sulfur compounds, and different structures. These may be combined, or a plurality of the same may be combined.

  The coupler used in the present invention can be used in the form of a solid dispersion with a water-soluble polymer using a sand mill or the like together with a basic substance and other color forming aids. Is particularly preferred. Preferred water-soluble polymers include water-soluble polymers used when preparing microcapsules (see, for example, JP-A-59-190886). In this case, the coupler, the basic substance, and the coloring aid are added to the water-soluble polymer solution in an amount of 5 to 40% by mass. The dispersed or emulsified particle size is preferably 10 μm or less.

  To the recording material of the present invention, for the purpose of reducing yellowing of the background after fixing, a free radical generator (compound that generates free radicals by light irradiation) used in a photopolymerizable composition or the like may be added. it can. Examples of such free radical generators include aromatic ketones, quinones, benzoin, benzoin ethers, azo compounds, organic disulfides, acyl oxime esters, and the like. The amount to be added is preferably 0.01 to 5 parts by mass of the free radical generator with respect to 1 part by mass of the diazo compound.

  Similarly, a polymerizable compound having an ethylenically unsaturated bond (hereinafter sometimes referred to as “vinyl monomer”) may be used for the purpose of reducing yellowing. The vinyl monomer is a compound having at least one ethylenically unsaturated bond (vinyl group, vinylidene group, etc.) in its chemical structure, and has a chemical form of monomer or prepolymer. Examples thereof include unsaturated carboxylic acids and salts thereof, esters of unsaturated carboxylic acids and aliphatic polyhydric alcohols, amide compounds of unsaturated carboxylic acids and aliphatic polyvalent amines, and the like.

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

  The recording material of the present invention is prepared by preparing a coating solution containing a microcapsule containing a diazo compound, a coupler, an organic base, and other additives, and coating a bar on a support such as paper or a synthetic resin film. It is preferable to provide a heat-sensitive layer having a solid content of 2.5 to 30 g / m 2 by coating and drying by a coating method such as coating, air knife coating, gravure coating, roll coating coating, spray coating, dip coating or curtain coating.

  In the recording material of the present invention, microcapsules, couplers, bases, and the like may be contained in the same layer, but it is also possible to adopt a laminated type constitution that is contained in another layer. Further, after providing an intermediate layer as described in Japanese Patent Application No. 59-177669 on the support, a heat-sensitive layer can be applied.

<Support>
As the support used in the recording material of the present invention, any of the paper supports used for ordinary pressure-sensitive paper, thermal paper, dry or wet diazo copy paper, etc. can be used, alkyl ketene dimer, etc. Sizing with a neutral sizing agent, neutral paper having a pH of 5 to 9 (as described in Japanese Patent Application No. 55-14281), Steiktite sizing degree and metric basis weight as described in Japanese Patent Application Laid-Open No. 57-116687 A paper having a Beck smoothness of 90 seconds or more, a paper having an optical surface roughness of 8 μm or less and a thickness of 30 to 150 μm described in JP-A-58-136492, Paper having a density of 0.9 g / cm 3 or less described in 58-69091 and an optical contact ratio of 15% or more, Canadian standard freeness (JIS P8121) described in JP-A-58-69097 40 Colored with the coated surface of glossy surface of the base paper made by Yankee machine described in JP-A-58-65695, which prevents the coating liquid made by pulping from pulp beaten to ml (400cc) or more. Paper with improved density and resolution. It is also possible to use paper that has been subjected to corona discharge treatment on the base paper described in Japanese Patent Application Laid-Open No. 59-35985 and whose coating suitability has been improved.

  Further, the synthetic resin film used as the support is not deformed by heating during the development process, and can be arbitrarily selected from known materials having dimensional stability. Examples of such a film include polyester films such as polyethylene terephthalate and polybutylene terephthalate, cellulose derivative films such as cellulose triacetate film, polystyrene films, polypropylene films, polyolefin films such as polyethylene, and the like. These can be used alone or in combination. The thickness of the support is 20 to 200 μm.

<Protective layer>
In the recording material of the present invention, if necessary, on the heat-sensitive recording layer for the purpose of preventing sticking or head contamination when printing on the heat-sensitive recording layer or imparting water resistance to the recording material. In addition, it is preferable to further provide a protective layer (hereinafter sometimes simply referred to as “protective layer”) containing polyvinyl alcohol or the like as a main component and added with various pigments, release agents and the like.

<Recording method>
When the recording surface of the recording material of the present invention thus obtained is heated with 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 and develop color. After recording, irradiation with light having an absorption wavelength of the diazo compound causes the diazo compound to decompose and lose reactivity with the coupler, so that the image is fixed.

  As the light source for fixing, various fluorescent lamps, xenon lamps, mercury lamps, LEDs, and the like are used. It is preferable that this emission spectrum substantially coincides with the absorption spectrum of the diazo compound used in the recording material because it can be efficiently photofixed. The recording material (heat-sensitive recording material) of the present invention is exposed using a manuscript, decomposes a diazo compound other than the image forming portion to form a latent image, and then develops the image by heating the recording material. You can also get

EXAMPLES Hereinafter, although an Example demonstrates this invention more concretely, this invention is not limited to this. In the following description, “part” means “part by mass” unless otherwise specified.
[Example 1]
<< Preparation of diazo thermosensitive recording material >>
(Adjustment of capsule liquid A)
To 18 parts of ethyl acetate, 3.0 parts of the diazonium salt (Exemplary Compound (D-38)) described above as a specific example and 9.5 parts of tricresyl phosphate were added and mixed uniformly. Next, 7.5 parts of Takenate D-110N (manufactured by Mitsui Takeda Chemical Co., Ltd.) was added as a wall material to this mixed liquid and mixed uniformly to obtain a liquid I.

The obtained liquid I was added to an aqueous phase consisting of 45.5 parts of an 8% by weight aqueous solution of phthalated gelatin, 16.6 parts of water, and 2.0 parts of a 10% aqueous solution of sodium dodecylbenzenesulfonate, and the mixture was 42 ° C · , 000 r. p. m. The mixture was emulsified and dispersed for 14 minutes. After adding 20 parts of water to the obtained emulsion and homogenizing it, an encapsulation reaction was carried out at 40 ° C. for 3.5 hours with further stirring to obtain a capsule liquid A. The capsule particle size was 0.34 μm.

(Adjustment of coupler liquid B)
In 7.8 parts of ethyl acetate, 4.0 parts of the coupler (Exemplary Compound (A-1)) described above as a specific example, 0.65 part of tricresyl phosphate and 0.33 part of diethyl maleate are dissolved. Obtained. The obtained II solution was added to an aqueous phase obtained by uniformly mixing 32 parts of a 15% by weight aqueous solution of lime-processed gelatin, 4.8 parts of a 10% aqueous solution of sodium dodecylbenzenesulfonate and 30 parts of water at 42 ° C. , Using a homogenizer at 40 ° C. and 10,000 r. p. m. The mixture was emulsified and dispersed for 13 minutes. The obtained emulsion was stirred at 40 ° C. for 3.0 hours to remove ethyl acetate, and then the masses of volatilized ethyl acetate and water were supplemented by hydration to obtain coupler liquid B.

(Adjustment of coating liquid C)
After 5.8 parts of capsule liquid A, 4.3 parts of water and 1.9 parts of a 15% by weight aqueous solution of lime-processed gelatin are uniformly mixed at 40 ° C., 8.0 parts of coupler liquid B is added and mixed uniformly. A thermal recording layer coating solution C was obtained.

(Adjustment of protective layer coating solution D)
Polyvinyl alcohol (polymerization degree 1700, saponification degree 88%) 10% aqueous solution 32 parts and water 34 parts were uniformly mixed to obtain protective layer coating liquid D.

(Application)
Apply the thermal recording layer coating solution C and protective layer coating solution D in this order with a wire bar on a photographic paper support with polyethylene laminated on high-quality paper, and dry at 50 ° C to obtain the desired diazo thermal recording material. Obtained. The coating amount as a solid content was 6.8 g / m ² and 1.05 g / m ² , respectively.

<Evaluation>
(Color development)
Using the thermal head (KST type) manufactured by Kyocera Corporation, select the applied power and pulse width for the thermal head so that the recording energy per unit area is 0 to 40 mJ / mm ^2. An image was obtained by thermal printing on a diazo thermosensitive recording layer. Next, the entire surface of the diazo thermal recording layer was irradiated with an ultraviolet lamp having an emission center wavelength of 365 nm and an output of 40 W for 15 seconds to fix the image. Thereafter, the maximum density of the background portion and the coloring portion of the obtained sample was measured using a Macbeth densitometer.

(Raw preservation)
First, the obtained diazo thermosensitive recording sheet was stored at room temperature (about 22 ° C.) for 48 hours, and after the image was formed and fixed in the same manner as described above, the density of the coloring portion and background portion was measured using a Macbeth densitometer. Measurement was made, and the difference between the maximum density of the color development part and the density of the background part (coloring density) before and after forced storage was compared and evaluated as raw storage stability. The results are shown in Table 1.

(Light fastness)
The sample developed and fixed as described above is continuously irradiated for 24 hours using a 32,000 Lux fluorescent lamp light fastness tester, and a color change test of the image portion and the background portion before and after the light irradiation is performed. went. For the measurement, the change in the density of the portion where the initial reflection density (color density of the image area before light irradiation) is 1.0 by a Macbeth densitometer was examined. The results are shown in Table 1.

[Examples 2 to 10]
Instead of the coupler (Exemplary Compound (A-1)) used in Example 1, couplers (A-2), (A-6), (A-12), (A-16), and (A-18), respectively. ), (A-24), (A-26), (A-28) and (A-31), except that the coupler liquid B was obtained. The diazo thermosensitive recording material used in No. 10 was produced and evaluated in the same manner. The results are shown in Table 1.

[Comparative Examples 1 and 2]
A diazo thermosensitive recording material was prepared in the same manner as in Example 1 except that the coupler liquid B was obtained using the following comparative compounds A and B instead of the coupler (Exemplary Compound (A-1)) used in Example 1. The same evaluation was performed. The results are shown in Table 1.

  From Table 1, the diazo heat-sensitive recording materials of Examples 1 to 6 using the pyrazole compound represented by the general formula (1) are excellent in color developability, have small exposure coloration on the background, and have raw preservation and light fastness. It was found to be excellent.

  According to the present invention, by using a pyrazole compound represented by the general formula (1) as a coupler, a recording material having excellent color developability, small exposure coloration on the background, and excellent raw storage and light fastness. Can be provided.

Claims (9)

A recording material comprising a recording layer containing a pyrazole compound represented by the following general formula (1) and a diazo compound on a support.

[In the general formula (1), R ¹ represents an aryl or aromatic heterocyclic group having two or more different alkoxy or aryloxy groups as substituents, and R ² represents an alkyl group, aryl group, alkoxy group, aryloxy group A group or an acylamino group. ] The recording material according to claim 1, wherein R ¹ is an aryl group. The recording material according to claim 1, wherein R ² is an alkyl group. 4. The recording material according to claim 1, wherein the pyrazole compound is a pyrazole compound represented by the following general formula (1a).

[In General Formula (1a), R ^1a represents an alkyl group or an aryl group, m represents an integer of 2 to 4, at least two of R ^1a are different from each other, and R ^2a represents an alkyl group. R ^3a represents a substituent, n represents an integer of 0 to 3, and OR ^1a , R ^3a or OR ^1a and R ^3a may be linked to each other to form a ring. ] The recording material according to any one of claims 1 to 4, wherein the diazo compound is a diazonium salt represented by the following general formula (2).

[In General Formula (2), R ⁴ and R ⁶ each independently represents an alkyl group, an aryl group, a heterocyclic group, or an acyl group. R ⁵ represents an alkyl group, an aryl group, an alkylsulfonyl group, an arylsulfonyl group, an acyl group, or a heterocyclic group. Y ¹ represents an oxygen atom, a sulfur atom, or an amino group, Y ² represents an oxygen atom, a sulfur atom, or a single bond, and Y ³ represents an oxygen atom, a sulfur atom, or a hydrogen atom. However, R ⁶ does not exist when Y ³ is a hydrogen atom. R ⁴ and R ⁶ may be bonded to each other to form a ring. X ⁻ represents an anion. ] 6. The recording material according to claim 5, wherein the diazonium salt is a diazonium salt represented by the following general formula (3).

[In General Formula (3), R ⁷ and R ⁸ each independently represents an alkyl group or an aryl group, and R ⁹ represents a hydrogen atom, an alkyl group, or an aryl group. X- represents an anion. ] 6. The recording material according to claim 5, wherein the diazonium salt is a diazonium salt represented by the following general formula (4).

[In General Formula (4), R ¹⁰ , R ¹¹ and R ¹² each independently represents an alkyl group or an aryl group. R ¹¹ and R ¹² may be bonded to each other to form a ring. X ⁻ represents an anion. ]   The recording material according to claim 1, wherein the diazo compound is encapsulated in a microcapsule.   The recording material according to claim 1, wherein the recording material is a heat-sensitive recording material.