JP2000347341A - Recording material with heat decolorable colored layer and heat developable photosensitive material - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a high sharpness photosensitive material with a colored layer which is stable in storage before processing and can rapidly be decolored by heating without causing discoloration by incorporating a specified thermal radical generating agent and a dye which is decolored by the generated radical into a colored layer. SOLUTION: The recording material has a heat decolorable colored layer (colored layer which is decolored by heating) containing a thermal radical generating agent which causes the homolytic cleavage of an intramolecular bond and generates a free radical when it is heated and a dye which is decolored by the generated radical. The thermal radical generating agent may be a thermal polymerization initiator such as a peroxide initiator, e.g. 2,2'- azobisisobutyronitrile or 2,2'-azobis(2,4-dimethylvaleronitrile).

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

[0001] The present invention relates to a recording material.
More specifically, the present invention relates to a recording material having, on a support, a colored layer which is easily decolored by heating.

[0002]

2. Description of the Related Art In a light-sensitive material, a light-sensitive silver halide emulsion layer or another layer is often colored in order to absorb a specific wavelength.

For example, when it is necessary to control the spectral composition of light to be incident on a silver halide emulsion layer, a colored layer is provided on a photographic light-sensitive material farther from the support than the emulsion layer. Such a colored layer is also called a filter layer. When there are a plurality of photographic emulsion layers such as a multilayer color light-sensitive material, a filter layer may be located between them.

Further, light scattered when passing through or after passing through the emulsion layer is reflected on the interface between the emulsion layer and the support or on the surface of the photosensitive material on the side opposite to the emulsion layer and reenters the emulsion layer. For the purpose of preventing image blurring due to the phenomenon, that is, halation, a coloring layer is provided between the emulsion layer and the support or on the surface of the support opposite to the emulsion layer. Such a colored layer is called an antihalation layer. In the case of a multi-layer color light-sensitive material, an antihalation layer may be provided between the layers.

Further, in order to prevent a decrease in image sharpness due to light scattering in the emulsion layer (this phenomenon is generally called irradiation), the emulsion layer is colored. Therefore, the colored layer must be decolored when exposed to light having a wavelength in the visible region and used as a mask for exposure or when directly viewed.

In the case where the exposure wavelength is in the infrared region, even if an anti-irradiation layer or an anti-halation layer is provided, it is possible to eliminate the need for decoloring the colored layer by selecting a dye having the smallest absorption in the visible region. it can. However, no infrared-absorbing dye having a sufficiently low absorption in the visible region and having a maximum absorption at 700 nm or more in a monomer state which is sufficiently stable even after treatment and does not generate colored stain has been found. Therefore,
Even when exposure is performed using light having a wavelength in the infrared region, it is necessary to decolor the absorption in the infrared to visible regions when using the film as a mask for exposure or directly viewing.

The above-described photosensitive material having a colored layer can be decolorized by liquid processing after exposure in a wet processing photosensitive material, but cannot be performed in a dry processing because such processing cannot be performed. Therefore, a mechanism for decoloring is required.

Several methods have been proposed for decoloring a colored layer in a dry processing photosensitive material. Some proposals to date include (1) U.S. Pat.
No. 9,019, No. 3,821,001, No. 4,0
No. 33,948, No. 4,088,497, No. 4,
Nos. 153,463 and 4,283,487, and JP-A Nos. 52-139136 and 53-132.
No. 334, No. 54-56818, No. 57-16060
And dyes which are decolorized by heat as described in JP-A-59-182436, or dyes which are decolorized by a corrosive gas generated from a counter salt upon heating described in US Pat. No. 4,347,401. A method using a colored layer as an antihalation layer, (2) o-nitroarylidene dyes described in U.S. Pat. No. 3,984,248 and JP-A-54-17833, or o-nitro-o-azaary. Liden dyes, as described in U.S. Pat. No. 3,770,451.
-O bond-cleavable dye, chrominium-type cyanine dye described in JP-A-2-229864, JP-A-59-1645.
No. 49, in which a colored layer containing a photo-decolorable dye such as an anionic dye containing a iodonium salt as a counter ion is used as an antihalation layer; -20734, described in JP-A-57-68831), azides (JP-A-63)
-14,028), ketone-based sensitizers (JP-A-5050)
-10618), mesoionic compounds (described in U.S. Pat. No. 4,548,895), iodonium compounds (described in U.S. Pat. No. 4,701,402), and active species generated by irradiating and / or heating these compounds. (4) A method in which a carbanion generator and a dye due to heat coexist in a colored layer to cause decoloration upon heating. (U.S. Pat. No. 5,135,842;
Nos. 5,258,274, 5,314,795, 5,324,627, 5,384,237, EP 605286, JP-A-6-222504, and 7
199409).

However, in the method (1), there is a possibility that decolorization may occur during storage before processing or extra heat fog may be caused depending on temperature conditions. In the method (2), a special method is used. Since a dye is used, there are problems such as difficulty in its synthesis and selection of a dye having a desired absorption wavelength. The following is a common problem with the methods (2) and (3). However, since a large amount of radiation is required for decoloring, there is a possibility that photo discoloration may occur in the heat developable photosensitive layer, or storage may occur. In many cases, the balance between the stability at the time and the decoloring property was insufficient. Another problem is that the processing takes time. (4)
In the method (1), there is a concern that the dye is not completely decolored or that the color is recolored by an acid.

[0010]

SUMMARY OF THE INVENTION The present invention addresses these prior art problems. That is, an object of the present invention is to provide a photosensitive material having a high image sharpness having a coloring layer which is extremely stable during storage before processing, but which can be easily erased without causing discoloration by heating when necessary. To provide. Another object of the present invention is to make it possible to select a dye from a wide range for imparting absorption characteristics of a desired wavelength to heat-decolorable coloring properties. Another object of the present invention is to provide a printing plate having good resolution, which has a coloring layer which is extremely stable during storage before processing but can be easily decolored without discoloration by heating when necessary. The present invention relates to a heat-developable ultra-high contrast photosensitive material suitable for use.

[0011]

The above object has been attained by the following constitutions. <1> In a recording material having a heat-decolorable colored layer (colored layer that is decolorized by heating), the colored layer generates free radicals by generating homoradical bonds in molecules by heating. A recording material, comprising a dye and a dye which is decolorized by generated radicals. <2> In a photothermographic material having a photothermographic layer containing at least a reducible silver salt, a photocatalytic substance and a reducing agent, free radicals are generated by homolytic cleavage of bonds in molecules at least by heating. A photothermographic material comprising at least one heat-decolorable colored layer containing a heat radical generator and a dye decolored by generated radicals. <3> The thermal development according to <2>, wherein the reducible silver salt in <2> is an organic silver salt, the photocatalytic substance is a photosensitive silver halide, and further contains a super-high contrast agent. Photosensitive material.

[0012]

BEST MODE FOR CARRYING OUT THE INVENTION

The heat-decolorizable coloring layer used in the present invention can be used for any of an emulsion layer and other hydrophilic colloid layers (intermediate layer, protective layer, antihalation layer, back layer, etc.). It may be used for a single layer or for multiple layers.

The heat-decolorable colored layer of the present invention absorbs unnecessary light at the time of image exposure to prevent halation and irradiation, thereby increasing the sharpness of an image formed, and also provides a radical generator during heat treatment. The dye is decolorized by the decolorization of the dye by the action of radicals generated by thermal decomposition of the dye or another radical generated by the reaction of the radicals.

The heat radical generator which generates a radical by heating, which can be used in the heat-decolorable coloring layer of the present invention, is known as a polymerization initiator.
R HANDBOOK ”(Brandrup, Immergut, Wiley Intersc)
ience, 1989). In the present invention, a thermal radical generator generally used as a thermal polymerization initiator can be used. Specifically, 2,
2'-azobisisobutyronitrile, 2,2'-azobis (2,4-dimethylvaleronitrile), dimethyl-
2,2′-azobis (2-methylpropionate), dimethyl-2,2′-azobisisobutyrate, 2-cyano
2-Propylazoformamide, 1,1'-azobis (cyclohexane-1-carbonitrile), 2,2'-azobis
(2-methylbutyronitrile), 2,2'-azobis (4-methoxy-2,4-dimethylvaleronitrile), 2,2'-azobis [2- (2-imidazolin-2-yl) propane], Azobis (azo initiators such as 2,4,4-trimethylpentane, lauryl peroxide, benzoyl peroxide, te
Peroxide initiators such as r-butyl peroctoate and the like can be mentioned. Among them, those having an appropriate decomposition rate are desirable in order to achieve both stability during storage and reactivity during heating. Examples of preferred thermal radical generators include 2,2'-azobisisobutyronitrile and 2,2 '
-Azobis (2,4-dimethylvaleronitrile), dimethyl-2,2'-azobis (2-methylpropionate), 1,1'-azobis (cyclohexane-1-carbonitrile), 2,2'-azobis (2-methylbutyronitrile), 2,2'-azobis [2- (2-imidazolin-2-yl)
Propane]. Among them, 2,2′-azobisisobutyronitrile, 1,1′-azobis (cyclohexane-1-carbonitrile), 2,2′-azobis (2-methylbutyronitrile), 2,2′-azobis [ 2- (2-imidazolin-2-yl) propane] is more preferred.

The amount of use of these thermal radical generators is sufficient to cause radicals generated when these thermal radical generators are heated or other radicals generated by the reaction thereof to decolorize the dye. It is necessary. Generally, an appropriate amount is determined by applying the composition in combination with a dye at various ratios, and generally about 0.1 mol to 100 mol, preferably 1 mol, of the thermal radical generator per 1 mol of the dye.
Molar to 10 moles are suitable.

The thermal radical generator may be used as a mixture of two or more kinds, and there is no limitation on the method of adding the same.

The dye used in the present invention has an intended absorption property and is decolorized by reacting with a radical generated from the radical generator or another radical generated by the reaction. If it is, basically anything can be used. For example, Dye Handbook (edited by The Society of Synthetic Organic Chemistry, Maruzen, published in 1978), Coloring Material 61 [4] 215-22
6 (1988) and Chemical Industry, 43-53 (198
Various dyes described in (June and May) can be used.

Preferred dyes used in the present invention are compounds represented by the following formulas (I) to (XIII).

[0020]

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[0021]

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[0022]

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In the formula, A ¹ and A ² each represent an acidic nucleus, A ³ represents a substituted or unsubstituted phenol, naphthol or an acidic nucleus, B ¹ represents a basic nucleus, and B ² represents a basic nucleus. Represents an onium form, Q ¹ , Q ² , Q ⁴ , Q ⁵ and Q ⁶ represent an aryl group or a heterocyclic group, Q ³ represents an onium form of an aryl group or a heterocyclic group, L ¹ , L ² , L ³ , L ⁴ , L ⁵ and L ⁶ each represent a methine group, m, s and u represent 0, 1, 2, n,
p and v each represent 0, 1, 2, 3;
1, 2, 3, 4 wherein r, t ₁ and t ₂ are each 1,
2 is represented. X ^- represents an anion, and W ¹ and W ² represent atoms necessary for forming a 5- or 6-membered carbocyclic or heterocyclic group.

The acidic nucleus represented by A ¹ , A ² or A ³ is preferably a cyclic ketomethylene compound or a compound having a methylene group sandwiched between electron-withdrawing groups. Examples of the cyclic ketomethylene compound include 2-pyrazolin-5-
On, rhodanin, hydantoin, thiohindantoin,
2,4-oxazolidinedione, isoxazolone, barbituric acid, thiobarbituric acid, indandione,
Dioxopyrazolopyridine, hydroxypyridine, pyrazolidinedione, 2,5-dihydrofuran-2-one,
Pyrrolin-2-one can be mentioned. These may have a substituent.

A methylene group sandwiched between electron-withdrawing groups.
Compound is Z¹CH_TwoZ^TwoWhere Z is¹, Z^Two
Are -CN and -SO, respectively._TwoR¹, −COR¹, -COOR^Two, -CONHR^Two,
−SO _TwoNHR^Two, -C (= C (CN)_Two] NHR¹Represents R¹Is archi
Represents an aryl group, an aryl group, or a heterocyclic group;^TwoIs hydrogen field
Child, or R¹And these are the groups represented by
Each may have a substituent.

[0026] Examples of the basic nucleus represented by B ^1, may be mentioned pyridine, quinoline, indolenine, oxazole, imidazole, thiazole, benzoxazole, benzimidazole, benzothiazole, oxazoline, a naphthoxazole pyrrole. Each of these may have a substituent. B ² is a onium form of a basic nucleus, examples may be mentioned onium form of a basic nucleus listed above B ^1.

Examples of the aryl group represented by Q ¹ , Q ² , Q ⁴ , Q ⁵ and Q ⁶ include a phenyl group and a naphthyl group, each of which may have a substituent. Q ¹ , Q ⁴ ,
Particularly as the substituents of Q ⁵ and Q ^6, a dialkylamino group,
A hydroxyl group and an alkoxy group are preferred. Q ² as the substituent nitro group, a cyano group, a sulfonyl group, a halogen atom, an electron withdrawing group. ^{Q 1, Q 2, Q 4} , Q 5 and Q ⁶
Examples of the heterocyclic group represented by, pyrrole, indole, furan, thiophene, imidazole, pyrazole,
Indolizine, quinoline, carbazole, phenothiazine, indoline, thiazole, pyridine, pyridazine,
Thiadiazine, pyran, thiopyran, oxadiazole, benzoquinoline, thiadiazole, pyrrolothiazole, pyrrolopyridazine, tetrazole, oxazole,
Coumarin and chroman can be mentioned. Each of these may have a substituent.

The onium compound represented by Q ³ is a phenyl group,
A naphthyl group or an onium group such as a quaternary ammonium group may be contained in the above-mentioned heterocyclic ring, or a hetero atom on the heterocyclic ring may be a cation to form an onium compound.

The methine groups represented by L ¹ , L ² , L ³ , L ⁴ , L ⁵ and L ⁶ may have a substituent, and the substituents are linked to each other to form 4,5 or , A 6- or 7-membered ring (eg, cyclobutene, cyclopentene, cyclohexene, cycloheptene).

X^-The anion represented by is the cation portion
To supply as many negative charges as necessary to neutralize the
And are monovalent or divalent ions. X
^-An example of the anion represented by^-, Br^-, I^-
Such as halogen ions, SO_Four ^2- , HSO_Four ^-, CH_ThreeOSO_Three ^-
Alkyl sulfate ions such as paratoluenesulfonic acid
On, naphthalene-1,5-disulfonic acid ion, meta
Sulfonic acid ion, trifluoromethanesulfonic acid ion
Sulfonate ions such as ON and octane sulfonate ions
, Acetate ion, p-chlorobenzoate ion, triflu
Oroacetate ion, oxalate ion, succinate ion, etc.
Carboxylate ion, PF₆ ^-, BF_Four ^-, ClO_Four ^-, I
O_Four ^-, Tungstate ion, tungstophosphate ion
Heteropolyacid ions such as_TwoPO_Four ^-, NO_Three ^-, Pic
Phenolate ions such as phosphate ions
You.

W ¹ and W ² represent atoms necessary for forming a 5- or 6-membered carbocyclic or heterocyclic group.

The substituents that each of the above groups may have are not particularly limited, and are specifically the same as those described above.
In addition, these substituents, or a substituent and A ¹ , A ² , A ³ ,
B ¹ , B ² and Q may be linked to each other to form a ring.

Specific examples of the dye which can be used in the present invention are shown below, but the present invention is not limited thereto.

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The dyes used in the present invention are described in International Patent WO88 / 04794 and European Patent EP with respect to dyes in the visible region.
274,723, 276,556, 299,4
No. 35, U.S. Pat. Nos. 2,527,583 and 3,48
Nos. 6,897, 3,746,539, 3,93
No. 3,798, No. 4,130,429, No. 4,04
0,841, JP-A-48-68,623 and JP-A-52-623.
92,716, 55-155,350, 55-
155,351, 61-205,934, JP-A-2-173,630, 2-230,135, 2-27
7,044, 2-282,244, 3-7,9
No. 31, 3-167, 546, 3-13, 937
No. 3-206,443, 3-208,047
Nos. 3-192, 157 and 3-216, 645
No. 3-274,043, No. 4-37,841,
JP-A-4-45,436, JP-A-4-138,449, JP-A-5-197,077, Japanese Patent Application No. 5-273,811,
The compounds can be synthesized according to the methods described in JP-A-6-7,761 and JP-A-6-155,727, or the like, or according to them. Regarding infrared dyes, European Patent Nos. 430244 and 5
No. 68267, U.S. Pat. Nos. 5,380,635;
009,989, JP-A-62-123,454, JP-A-2-282,244, JP-A-3-9,346, and JP-A-3-9346.
-138,640, 31-21,542, 3-
Nos. 226,736, 4-13,654 and 4-19
No. 0,343, 5-313,305, 5-32
No. 3,500, No. 5-323, 501, No. 6-43,
Nos. 583, 9-96, 891, 10-36, 69
The compound can be synthesized according to the method described in No. 5 or the like or a method analogous thereto.

Accordingly, the use of the radical generator of the present invention makes it possible to select from among a very wide range of dyes those having a suitable absorption characteristic. Among them, general formulas (I), (II) and (I
The dyes represented by V), (V), (VI), (IX), (XII) and (XIII) are preferred, and among them, the general formulas (I), (IV),
The dyes represented by (V), (XII) and (XIII) are particularly preferred from the viewpoint of decoloring property.

The dye used in the present invention can be used in any effective amount, but is preferably used so that the optical density is in the range of 0.05 to 3.5. More preferably, it is within the range. The timing of addition may be any step before coating. Moreover, 360-7 after processing
The optical density at 50 nm is preferably in the range of 0.05 to 0.3.

The dye of the present invention may be added by any method and may be added as a solution or a solid fine particle dispersion. The dye is substantially insoluble in water and has a boiling point of 160 ° C. or higher. A method in which a solution dissolved in an organic solvent having a boiling point of 30 ° C. to 150 ° C. is added to the hydrophilic colloid layer and dispersed therein, A method of incorporating a dye as a polymer latex composition filled with a photographic emulsion layer or other hydrophilic colloid layer can also be used.

The temperature and time required for the decolorization of the infrared absorbing layer by the heat treatment depend on the type of the thermal radical generator. The processing temperature is preferably 70 to 200 ° C, and 80 to 15 ° C.
0 ° C. is more preferred. An appropriate thermal radical generator can be appropriately selected depending on the processing temperature and the processing time. The processing time is preferably from 3 to 150 seconds, more preferably from 3 to 30 seconds.

In the present invention, a photosensitive silver halide is preferably used as a photocatalytic substance, and an organic silver salt is preferably used as a reducible silver salt. The method of forming the photosensitive silver halide in the present invention is well known in the art, and for example, the methods described in Research Disclosure No. 17029 of June 1978 and US Pat. No. 3,700,458 can be used. Specific methods that can be used in the present invention include a method of converting a part of the silver of the organic silver salt to a photosensitive silver halide by adding a halogen-containing compound to the prepared organic silver salt, gelatin. Alternatively, a method of preparing a photosensitive silver halide grain by adding a silver supply compound and a halogen supply compound to another polymer solution and mixing the resultant with an organic silver salt can be used. In the present invention, the latter method can be preferably used. The grain size of the photosensitive silver halide is preferably small for the purpose of suppressing white turbidity after image formation, specifically, 0.20 μm or less, more preferably 0.01 μm or less.
μm or more and 0.15 μm or less, more preferably 0.02 μm or more and 0.1
It is preferably 2 μm or less. Here, the grain size means the length of the edge of the silver halide grain when the silver halide grain is a cubic or octahedral so-called normal crystal. In the case where the silver halide grains are tabular grains, the diameter refers to a diameter when converted into a circular image having the same area as the projected area of the main surface. In the case of other than normal crystals, for example, in the case of spherical grains, rod-shaped grains, etc., it refers to the diameter of a sphere equivalent to the volume of silver halide grains.

The shape of the silver halide grains is cubic,
Octahedral, tabular particles, spherical particles, rod-like particles, potato-like particles and the like can be mentioned. In the present invention, cubic particles and tabular particles are particularly preferable. When tabular silver halide grains are used, the average aspect ratio is preferably from 100: 1 to 2: 1, more preferably from 50: 1 to 3: 1. Further, grains having rounded corners of silver halide grains can also be preferably used. The surface index (mirror index) of the outer surface of the photosensitive silver halide grains is not particularly limited, but the spectral sensitizing efficiency when the spectral sensitizing dye is adsorbed is high. preferable. The ratio is preferably at least 50%, more preferably at least 65%, even more preferably at least 80%. The ratio of the Miller index ｛100｝ plane is determined by the adsorption dependence of the sensitizing dye between the ｛111｝ plane and the ｛100｝ plane.T.Tani; J.Imaging Sci., 29,
165 (1985).
The halogen composition of the photosensitive silver halide is not particularly limited, and may be any of silver chloride, silver chlorobromide, silver bromide, silver iodobromide, silver iodochlorobromide, and silver iodide. In the present invention, silver bromide or silver iodobromide can be preferably used. Particularly preferred is silver iodobromide, and the silver iodide content is preferably from 0.1 mol% to 40 mol%,
The content is more preferably from 0.1 mol% to 20 mol%. The distribution of the halogen composition in the grains may be uniform, the halogen composition may be changed stepwise, or may be changed continuously, but as a preferred example, the silver iodide content inside the grains is High silver iodobromide grains can be used. Preferably, silver halide grains having a core / shell structure can be used. The structure is preferably a 2- to 5-fold structure, more preferably a 2- to 5-layer structure.
Quadruplex core / shell particles can be used.

The photosensitive silver halide grains of the present invention preferably contain at least one complex of a metal selected from rhodium, rhenium, ruthenium, osmium, iridium, cobalt, mercury or iron. One type of these metal complexes may be used, or two or more types of complexes of the same metal and different metals may be used in combination. The preferred content is in the range of 1 nmol to 10 mmol per mol of silver, preferably 10 mol.
More preferably, the range is from n mol to 100 μmol. As a specific structure of the metal complex, a metal complex having a structure described in JP-A-7-225449 or the like can be used. cobalt,
As the iron compound, a hexacyano metal complex can be preferably used. Specific examples include ferricyanate ion, ferrocyanate ion, hexacyanocobaltate ion, and the like, but are not limited thereto. Even if the content of the metal complex in the silver halide is uniform,
The core portion may be contained at a high concentration, or the shell portion may be contained at a high concentration, and there is no particular limitation.

The photosensitive silver halide grains can be desalted by washing with a method known in the art such as a noodle method or a flocculation method, but in the present invention, it may or may not be desalted. .

The photosensitive silver halide grains in the present invention are preferably chemically sensitized. As a preferred chemical sensitization method, a sulfur sensitization method, a selenium sensitization method, and a tellurium sensitization method are well known in the art. Further, a noble metal sensitization method or a reduction sensitization method of a gold compound, platinum, palladium, an iridium compound or the like can be used. As the compound preferably used in the sulfur sensitization method, the selenium sensitization method, and the tellurium sensitization method, known compounds can be used, and the compounds described in JP-A-7-128768 can be used. Examples of tellurium sensitizers include diacyl tellurides, bis (oxycarbonyl) tellurides,
Bis (carbamoyl) tellurides, diacyltellurides, bis (oxycarbonyl) ditellurides, bis (carbamoyl) ditellurides, compounds having a P = Te bond,
Tellurocarboxylates, Te-organyltellurocarboxylates, di (poly) tellurides, tellurides,
Tellurols, telluroacetals, tellursulfonates, compounds having a P-Te bond, Te-containing heterocycles, tellurocarbonyl compounds, inorganic tellurium compounds, colloidal tellurium, and the like can be used. Compounds preferably used in the noble metal sensitization method include, for example, chloroauric acid, potassium chloroaurate, potassium aurithiocyanate,
Gold sulfide, gold selenide, or US Patent 2,448,060
And the compounds described in British Patent No. 618,061 can be preferably used. Specific compounds of the reduction sensitization method include, as well as ascorbic acid, thiourea dioxide, for example, stannous chloride, aminoiminomethanesulfinic acid, hydrazine derivatives, borane compounds, silane compounds,
A polyamine compound or the like can be used. Reduction sensitization can be achieved by ripening the emulsion while maintaining the pH of the emulsion at 7 or more or the pAg at 8.3 or less. Further, reduction sensitization can be achieved by introducing a single addition portion of silver ion during grain formation.

The amount of the photosensitive silver halide used in the present invention is preferably 0.01 mol 0.5 mol or less, more preferably 0.02 mol or more and 0.3 mol or less, more preferably 0.03 mol or less, per 1 mol of the organic silver salt. Particularly preferred is 0.25 mol or less. Regarding the mixing method and the mixing conditions of the separately prepared photosensitive silver halide and organic silver salt, the prepared silver halide particles and organic silver salt were mixed with a high-speed stirrer, a ball mill, a sand mill, a colloid mill, a vibration mill, and a homogenizer. And the like, or a method of preparing an organic silver salt by mixing photosensitive silver halide prepared at any timing during the preparation of the organic silver salt. There is no particular limitation as long as it appears in.

As the silver halide preparation method of the present invention, a so-called halation method in which a part of silver of an organic silver salt is halogenated with an organic or inorganic halide is also preferably used. The organic halide used here may be any compound as long as it is a compound which reacts with an organic silver salt to form a silver halide, and includes N-halogenoimides (such as N-bromosuccinimide) and quaternary nitrogen halides (e.g. Tetrabutylammonium bromide, etc.), associates of halogenated quaternary nitrogen salts with halogen molecules (pyridinium bromide perbromide)
And the like. The inorganic halogen compound may be any compound as long as it reacts with an organic silver salt to form a silver halide, and includes an alkali metal halide or ammonium halide (such as sodium chloride, lithium bromide, potassium iodide, ammonium bromide, etc.). ), Alkaline earth metal halides (calcium bromide, magnesium chloride, etc.), transition metal halides (ferric chloride, cupric bromide, etc.), metal complexes having halogen ligands (sodium iridium bromide) , Ammonium rhodate, etc.), and halogen molecules (bromine, chlorine, iodine). Further, a desired organic / inorganic halide may be used in combination.

In the present invention, the amount of the halide to be added is preferably 1 to 500 mmol, more preferably 10 to 25 mmol, as a halogen atom per 1 mol of the organic silver salt.
0 mmol is more preferred.

The organic silver salt that can be used in the present invention includes:
Relatively stable to light, but forms a silver image when heated to 80 ° C or higher in the presence of an exposed photocatalyst (such as a latent image of a photosensitive silver halide) and a reducing agent It is a silver salt. The organic silver salt can be any organic substance including a source capable of reducing silver ions. Silver salts of organic acids,
Particularly, a silver salt of a long-chain fatty carboxylic acid (having 10 to 30 carbon atoms, preferably 15 to 28 carbon atoms) is preferred. Complexes of organic or inorganic silver salts whose ligands have a complex stability constant in the range of 4.0 to 10.0 are also preferred. The silver donor material is preferably about 5% of the image forming layer.
Up to 70% by weight. Preferred organic silver salts include silver salts of organic compounds having a carboxyl group. Examples of these include, but are not limited to, silver salts of aliphatic carboxylic acids and silver salts of aromatic carboxylic acids.
Preferred examples of the silver salt of an aliphatic carboxylic acid include silver behenate, silver arachidate, silver stearate, silver oleate, silver laurate, silver caproate, silver myristate, silver palmitate, silver maleate, and fumarate. Silver acid, silver tartrate,
Silver linoleate, silver butyrate and silver camphorate, and mixtures thereof.

A silver salt of a compound containing a mercapto group or a thione group and derivatives thereof can also be used.
Preferred examples of these compounds include silver salts of 3-mercapto-4-phenyl-1,2,4-triazole,
Silver salt of mercaptobenzimidazole, silver salt of 2-mercapto-5-aminothiadiazole, silver salt of 2- (ethylglycolamide) benzothiazole, S-alkylthioglycolic acid (where the alkyl group has 12 carbon atoms)
-22), such as a silver salt of thioglycolic acid;
Silver salt of dithiocarboxylic acid such as silver salt of dithioacetic acid, silver salt of thioamide, silver salt of 5-carboxyl-1-methyl-2-phenyl-4-thiopyridine, silver salt of mercaptotriazine, and silver salt of 2-mercaptobenzoxazole Silver salt,
Silver salts described in U.S. Pat. No. 4,123,274, for example silver salts of 1,2,4-mercaptothiazole derivatives such as silver salts of 3-amino-5-benzylthio-1,2,4-thiazole;
Silver salts of thione compounds such as the silver salt of 3- (3-carboxyethyl) -4-methyl-4-thiazoline-2-thione described in U.S. Pat. No. 3,301,678. Furthermore, compounds containing an imino group can also be used. Preferred examples of these compounds include silver salts of benzotriazole and derivatives thereof, for example, silver salts of benzotriazole such as silver methylbenzotriazole, silver salts of halogen-substituted benzotriazole such as silver 5-chlorobenzotriazole, and US Pat. 4,220,709, such as silver salts of 1,2,4-triazole or 1-H-tetrazole, and silver salts of imidazole and imidazole derivatives. For example, U.S. Pat.
Various silver acetylide compounds such as those described in 761,361 and 4,775,613 can also be used.

The shape of the organic silver salt that can be used in the present invention is not particularly limited, but a needle crystal having a short axis and a long axis is preferable. In the present invention, the minor axis is 0.01 μm or more.
20 μm or less, major axis 0.10 μm or more and 5.0 μm or less, minor axis 0.01 μm or more and 0.15 μm or less, major axis 0.10 μm or more
It is more preferably 4.0 μm or less. The particle size distribution of the organic silver salt is preferably monodispersed. Monodispersion means that the percentage of the value obtained by dividing the standard deviation of the length of each of the minor axis and major axis by the minor axis and major axis is preferably 100% or less, more preferably 80% or less, and still more preferably 50% or less. is there. The shape of the organic silver salt can be measured from a transmission electron microscope image of the organic silver salt dispersion. As another method of measuring the monodispersity, there is a method of obtaining the standard deviation of the volume-weighted average diameter of the organic silver salt, and the percentage (coefficient of variation) divided by the volume-weighted average diameter is preferably 100% or less,
It is more preferably at most 80%, further preferably at most 50%. As a measuring method, for example, the organic silver salt dispersed in a liquid is irradiated with laser light, and the particle size (volume weight average diameter) obtained by obtaining an autocorrelation function with respect to a time change of the fluctuation of the scattered light is obtained. Can be.

The organic silver salt that can be used in the present invention includes:
Preferably, desalting can be performed. The method for desalting is not particularly limited, and a known method can be used. However, a known filtration method such as centrifugal filtration, suction filtration, ultrafiltration, and floc-forming water washing by a coagulation method can be preferably used. .

For the purpose of obtaining fine particles having a small particle size and no aggregation, a method of preparing a solid fine particle dispersion using a dispersant is used for the organic silver salt which can be used in the present invention. The method of dispersing the organic silver salt into solid fine particles is carried out by using a known fine means (for example, a ball mill, a vibrating ball mill, a planetary ball mill, a sand mill, a colloid mill, a jet mill, a roller mill) in the presence of a dispersing agent. Can be dispersed.

When the organic silver salt is formed into solid fine particles using a dispersant, for example, polyacrylic acid, a copolymer of acrylic acid, a maleic acid copolymer, a maleic acid monoester copolymer, and acryloylmethyl Synthetic anionic polymers such as propane sulfonic acid copolymer, semi-synthetic anionic polymers such as carboxymethyl starch and carboxymethyl cellulose, anionic polymers such as alginic acid and pectic acid, JP-A-52-92716, WO88 / 04794, etc. Anionic surfactant described, the compound described in Japanese Patent Application No. 7-350753, or known anionic, nonionic,
Cationic surfactants and other known polymers such as polyvinyl alcohol, polyvinylpyrrolidone, carboxymethylcellulose, hydroxypropylcellulose, and hydroxypropylmethylcellulose, or high-molecular compounds existing in nature such as gelatin can be appropriately selected and used. .

It is a general method that the dispersing aid is mixed with an organic silver salt powder or an organic silver salt in a wet cake state before dispersion and then sent as a slurry to a dispersing machine. Heat treatment or treatment with a solvent may be performed in the combined state to obtain an organic silver salt powder or a wet cake. The pH may be controlled by a suitable pH adjuster before, during or after dispersion.

Instead of mechanically dispersing, fine particles may be formed by coarsely dispersing in a solvent by controlling the pH and then changing the pH in the presence of a dispersing aid. At this time, an organic solvent may be used as a solvent used for the coarse dispersion, and the organic solvent is usually removed after the completion of the fine particle formation.

The prepared dispersion is stored with stirring for the purpose of suppressing sedimentation of the fine particles during storage, or stored in a highly viscous state by a hydrophilic colloid (for example, in a jelly state using gelatin). You can also do.
Further, a preservative can be added for the purpose of preventing the propagation of various bacteria during storage.

[0085] The organic silver salt of the present invention can be used in a desired amount, preferably 0.1-5 g / m ^2, more preferably is 1 to 3 g / m ² expressed in an amount per photographic material 1 m ² .

The reducing agent used in the present invention may be any substance which reduces silver ions to metallic silver, preferably an organic substance. Conventional photographic developers such as phenidone, hydroquinone and catechol are useful, but hindered phenol reducing agents are preferred. The reducing agent is preferably contained in an amount of 5 to 50% (mole), more preferably 10 to 40% (mole), based on 1 mol of silver on the surface having the image forming layer. The layer to which the reducing agent is added may be any layer on the side having the image forming layer. When it is added to a layer other than the image forming layer, it is preferable to use a relatively large amount of 10 to 50% (mol) with respect to 1 mol of silver. Further, the reducing agent may be a so-called precursor which is derivatized so as to have a function effectively only during development.

In a photothermographic material utilizing an organic silver salt, a wide range of reducing agents are disclosed in JP-A-46-6074 and JP-A-47-1238.
No. 47-33621, No. 49-46427, No. 49-115540, No.
50-14334, 50-36110, 50-147711, 51-326
No. 32, No. 51-1023721, No. 51-32324, No. 51-51933,
52-84727, 55-108654, 56-146133, 57
-82828, 57-82829, JP-A-6-3793, U.S. Pat.
667,9586, 3,679,426, 3,751,252, 3,75
No. 1,255, No. 3,761,270, No. 3,782,949, No. 3,839,
No. 048, 3,928,686, 5,464,738, German patent 23
No. 21328 and European Patent No. 692732. For example, amide oximes such as phenylamidooxime, 2-thienylamidooxime and p-phenoxyphenylamidooxime; azines such as 4-hydroxy-3,5-dimethoxybenzaldehydeazine; 2,2-bis (hydroxymethyl) propionyl- a combination of an aliphatic carboxylic acid aryl hydrazide such as a combination of β-phenylhydrazine and ascorbic acid with ascorbic acid; a combination of polyhydroxybenzene with hydroxylamine, reductone and / or hydrazine (eg, hydroquinone, bis (ethoxyethyl) ) Hydroxylamine, piperidinohexose reductone or formyl-4
-Hydroxamic acids such as phenylhydroxamic acid, p-hydroxyphenylhydroxamic acid and β-alinine hydroxamic acid; combinations of azine and sulfonamidophenol (for example, phenothiazine and 2,6-dichloro-). 4-benzenesulfonamidophenol, etc.); ethyl-α-cyano-2-
Α-cyanophenylacetic acid derivatives such as methylphenylacetate and ethyl-α-cyanophenylacetate; 2,
2-dihydroxy-1,1-binaphthyl, 6,6-dibromo-2,2-
Bis-β- as exemplified by dihydroxy-1,1-binaphthyl and bis (2-hydroxy-1-naphthyl) methane
Naphthol; a combination of bis-β-naphthol and a 1,3-dihydroxybenzene derivative (eg, 2,4-dihydroxybenzophenone or 2,4-dihydroxyacetophenone); 3-methyl-1-phenyl-5-pyrazolone, Five-
Pyrazolones; reductones as exemplified by dimethylaminohexose reductone, anhydrodihydroaminohexose reductone and anhydrodihydropiperidone hexose reductone; 2,6-dichloro-4-benzenesulfonamidophenol and p- Sulfonamidophenol reducing agents such as benzenesulfonamidophenol; 2-phenylindane-1,3-dione; chromanes such as 2,2-dimethyl-7-t-butyl-6-hydroxychroman; 2,6-dimethoxy- 1,4-dihydropyridines such as 3,5-dicarbethoxy-1,4-dihydropyridine; bisphenols (eg, bis (2-hydroxy-3-t-butyl-5-methylphenyl) methane, 2,2-bis ( 4-hydroxy-3-methylphenyl) propane, 4,4-ethylidene-bis (2-t-
Butyl-6-methylphenol), 1,1, -bis (2-hydroxy-3,5-dimethylphenyl) -3,5,5-trimethylhexane and 2,2-bis (3,5-dimethyl-4- Hydroxyphenyl) propane, etc.); ascorbic acid derivatives (for example,
Such as 1-ascorbyl palmitate, ascorbyl stearate); and aldehydes and ketones such as benzyl and biacetyl; 3-pyrazolidone and certain indan-1,3-diones; chromanol (such as tocopherol). Particularly preferred reducing agents are bisphenol and chromanol.

The reducing agent of the present invention may be added by any method such as a solution, a powder, and a dispersion of solid fine particles. The dispersion of the solid fine particles is carried out by a known means for making fine (for example, a ball mill, a vibration ball mill, a sand mill, a colloid mill, a jet mill, a roller mill, etc.). When dispersing the solid fine particles, a dispersing aid may be used.

When an additive known as a “toning agent” for improving an image is contained, the optical density may be increased. The toning agent may also be advantageous in forming a black silver image. The toning agent is preferably contained in an amount of 0.1 to 50% (mol) per mol of silver on the surface having the image forming layer, and more preferably 0.5 to 20% (mol). Further, the toning agent may be a so-called precursor which is derivatized so as to have a function effectively only during development.

In a photothermographic material utilizing an organic silver salt, a wide range of toning agents are disclosed in JP-A-46-6077 and JP-A-47-10282.
Nos. 49-5019, 49-5020, 49-91215, 49
-91215, 50-5024, 50-32927, 50-67132
No. 50-67641, No. 50-114217, No. 51-3223, No. 5
1-27923, 52-14788, 52-99813, 53-1020
No. 53-76020, No. 54-156524, No. 54-156525,
No. 61-183642, JP-A-4-56848, JP-B-49-10727
No. 54-20333, U.S. Pat.Nos. 3,080,254, 3,446,64
No. 8, 3,782,941, 4,123,282, 4,510,236
And British Patent 1,380,795 and Belgian Patent 841,910. Examples of toning agents are phthalimide and N-hydroxyphthalimide; succinimide, pyrazolin-5-one, and quinazolinone, 3-phenyl-2-
Cyclic imides such as pyrazolin-5-one, 1-phenylurazole, quinazoline and 2,4-thiazolidinedione;
Naphthalimide (eg, N-hydroxy-1,8-naphthalimide); cobalt complex (eg, cobalt hexamine trifluoroacetate); 3-mercapto-1,2,4-triazole, 2,4-dimercaptopyrimidine, 3 -Mercapto
Mercaptans exemplified by -4,5-diphenyl-1,2,4-triazole and 2,5-dimercapto-1,3,4-thiadiazole; N- (aminomethyl) aryldicarboximides (for example, (N , N-dimethylaminomethyl) phthalimide and N, N- (dimethylaminomethyl) -naphthalene-
2,3-dicarboximide); and blocked pyrazoles, isothiuronium derivatives, and certain photobleaching agents (eg, N, N'-hexamethylenebis (1-carbamoyl-3,5-dimethylpyrazole), 1,8 -(3,6-diazaoctane) bis (isothiuronium trifluoroacetate) and 2-tribromomethylsulfonyl)-(benzothiazole)); and 3-ethyl-5 [(3-ethyl-2-benzothiazolini) Ridene) -1-methylethylidene] -2-thio-
2,4-oxazolidinedione; phthalazinone, phthalazinone derivative or metal salt, or 4- (1-naphthyl) phthalazinone, 6-chlorophthalazinone, 5,7-dimethoxyphthalazinone and 2,3-dihydro-1,4- Derivatives such as phthalazinedione; combinations of phthalazinone with phthalic acid derivatives (eg, phthalic acid, 4-methylphthalic acid, 4-nitrophthalic acid and tetrachlorophthalic anhydride); phthalazine, phthalazine derivatives or metal salts, or (1
-Naphthyl) derivatives such as phthalazine, 6-chlorophthalazine, 5,7-dimethoxyphthalazine and 2,3-dihydrophthalazine; phthalazine and phthalic acid derivatives (eg phthalic acid, 4-methylphthalic acid, 4-nitrophthalic acid) And quinazolinedione, benzoxazine or naphthoxazine derivatives; a rhodium complex which functions not only as a color tone regulator but also as a source of halide ions for silver halide formation in situ; For example, ammonium hexachlororhodate (III), rhodium bromide, rhodium nitrate and potassium hexachlororhodate (III); inorganic peroxides and persulfates, such as ammonium disulfide and hydrogen peroxide; Benzoxazine-2,4-dione, 8-methyl-1,3-benzoxazine-2,4-di And benzoxazine-2,4-diones such as 6-nitro-1,3-benzoxazine-2,4-dione; pyrimidines and asymmetric triazines (eg, 2,4-dihydroxypyrimidine, 2-hydroxy-4- Aminopyrimidine, etc.), azauracil, and tetraazapentalene derivatives (eg, 3,6-dimercapto-1,4-diphenyl-1H, 4H-2,3a, 5,6a-tetraazapentalene, and 1,4- And di (o-chlorophenyl) -3,6-dimercapto-1H, 4H-2,3a, 5,6a-tetraazapentalene.

The color-toning agent of the present invention may be added by any method such as a solution, a powder, and a solid fine particle dispersion. The dispersion of the solid fine particles is carried out by a known means for making fine (for example, a ball mill, a vibration ball mill, a sand mill, a colloid mill, a jet mill, a roller mill, etc.). When dispersing the solid fine particles, a dispersing aid may be used.

As the binder for the emulsion layer in the present invention, well-known natural or synthetic resins such as gelatin, polyvinyl acetal, polyvinyl chloride,
Any one can be selected from polyvinyl acetate, cellulose acetate, polyolefin, polyester, polystyrene, polyacrylonitrile, polycarbonate and the like. Of course, copolymers and terpolymers are also included. Preferred polymers are polyvinyl butyral, butylethyl cellulose, methacrylate copolymer, maleic anhydride copolymer, polystyrene and butadiene-styrene copolymer. If necessary, two or more of these polymers can be used in combination. Such a polymer is used in an amount sufficient to hold the components therein. That is, it is used in a range effective to function as a binder.

In the present invention, a binder obtained by dispersing a hydrophobic polymer in an aqueous solvent may be used as the binder for the emulsion layer. The aqueous solvent here is water or a mixture of water and 70% by weight or less of a water-miscible organic solvent. Examples of the water-miscible organic solvent include methanol, ethanol, propanol, ethyl acetate, dimethylformamide, methyl cellosolve, butyl cellosolve and the like. As specific solvent compositions, water / methyl alcohol = 90/10 or 70/30 or 50/50, water / isopropyl alcohol = 90/10, water / butyl cellosolve = 95/5, water / dimethylformamide = 95.
/ 5, water / methyl alcohol / dimethylformamide =
90/5/5 or 80/15/5 (or more by weight).

The term "dispersion" as used herein refers to a state in which the polymer is not thermodynamically dissolved in the solvent but is dispersed in the aqueous solvent in the form of latex, micelle, or molecule. As the binder of the present invention, among these polymers, those having an "equilibrium water content at 25 ° C. and 60% RH" of 2 wt% or less are particularly preferred. The lower limit of the equilibrium water content is not particularly limited, but is preferably 0.01 wt%, more preferably 0.03 wt%. Here, the “equilibrium moisture content at 25 ° C and 60% RH” is the weight of the polymer that has reached the humidity control equilibrium in an atmosphere of 25 ° C and 60% RH, and the weight of the polymer that has been completely dried at 25 ° C.
It can be expressed as follows using W0.

“Equilibrium moisture content at 25 ° C. and 60% RH” = ｛(W
1-W0) / W0｝ × 100 (wt%) The polymer of the present invention is not particularly limited as long as it can be dispersed in the above-mentioned aqueous solvent.For example, acrylic resin, polyester resin, polyurethane resin, vinyl chloride resin, chloride Examples include vinylidene resin, rubber-based resin (for example, SBR resin, NBR resin, etc.), vinyl acetate resin, polyolefin resin, polyvinyl acetal resin, and the like.
The polymer may be a homopolymer or a copolymer in which two or more monomers are polymerized. The polymer may be linear or branched. Further, the polymers may be crosslinked. The number average molecular weight of the polymer is 1,000 to 1,000,000, preferably 3,0
A value of 00 to 500,000 is desirable. Number average molecular weight is 1,000
If it is less, the film strength after application is generally low, which may cause inconvenience such as cracking of the photosensitive material. Of these, styrene-butadiene copolymers are preferred, although they are included in the above SBR resin.

The "styrene-butadiene copolymer" used in the present invention is a polymer containing styrene and butadiene in the molecular chain. The molar ratio of styrene-butadiene is preferably from 99: 1 to 40:60.

The "styrene-butadiene copolymer" of the present invention also includes esters of acrylic acid or methacrylic acid such as methyl methacrylate and ethyl methacrylate, acids such as acrylic acid, methacrylic acid and itaconic acid, or acrylonitrile. Other vinyl monomers such as divinylbenzene may be copolymerized. Preferably, styrene-butadiene is present at 50% by weight or more.

The styrene-butadiene copolymer used in the present invention has a number average molecular weight of 2,000 to 1,
1,000,000, more preferably 5,000-500,
A range of 000 is preferred.

The styrene-butadiene copolymer of the present invention is usually a random copolymer, but these copolymers may be linear polymers, branched or crosslinked. Usually, it is used as particles having an average particle size of about 0.01 to 1 μm.

Specific examples of the polymer of the present invention include acrylic resins such as Sebian A-4635, 46584, and 4601 (all manufactured by Daicel Chemical Industries, Ltd.), Nipol LX811, 814, and 820;
821, 857 (all made by Nippon Zeon Co., Ltd.), and polyester resins such as FINETEX ES650, 611, 679, 67
5, 525, 801 and 850 (all manufactured by Dainippon Ink and Chemicals, Inc.)
, Wdsize WMS (Eastman Chemical) and others. Specific examples of the rubber-based (SBR) resin or styrene-butadiene copolymer are as follows.

Latex of P-1-St70-Bu30- (Mn = 30000) Latex of P-2-St60-Bu37-MAA3- (Mn = 45000) Latex of P-3-St50-Bu40-AN7-AA3- ( (Mn = 70000) Latex of P-4-St70-Bu20-DVB5-MAA5- (Mn = 100000) Latex of P-5-St50-Bu30-AN15-IA5- (Mn = 60000) The abbreviations are shown below. It represents a structural unit derived from a monomer, and a numerical value is% by weight and Mn is a number average molecular weight.

St: styrene, Bu: butadiene, MA
A: methacrylic acid, AN: acrylonitrile, AA: acrylic acid, DVB: divinylbenzene IA: itaconic acid Further, Luxter 3307B, DS-205, 602, Luxstar DS203, 7132C, DS807 (Dai Nippon Ink Chemical Co., Ltd. )), Nippol 2507, Lx41
6, Lx433, Lx410, Lx430, Lx435
(Nippon Zeon Co., Ltd.), DL-670, L-57
02, 1235 (these are Asahi Kasei Corporation).

In the binder of the present invention, these polymers may be used alone or in combination of two or more.

In the present invention, when a styrene-butadiene copolymer which is preferably used as a binder is used, the above-mentioned solvent is used to prepare a coating solution having a solid concentration of 0.5 to 12% by weight.
More preferably, it is in the range of 1 to 8% by weight.

The effective range of the amount of the binder used can be appropriately determined by those skilled in the art. As a guide when at least the organic silver salt is retained, the ratio of the binder to the organic silver salt is 15: 1 to 1: 3 by weight, especially 8: 1 to 1: 2.
Is preferable.

As the sensitizing dye in the present invention, any dye can be used as long as it can spectrally sensitize the silver halide grains in a desired wavelength region when adsorbed on the silver halide grains. As the sensitizing dye, a cyanine dye, a merocyanine dye, a complex cyanine dye, a complex merocyanine dye, a holopolar cyanine dye, a styryl dye, a hemicyanine dye, an oxonol dye, a hemioxonol dye, and the like can be used. Useful sensitizing dyes for use in the present invention include, for example, RESEARCH DISCLOSURE Item 17
Item 643IV-A (p.23, December 1978), Item 1831 Item X (1979
August, p. 437). Especially various laser imagers, scanners,
A sensitizing dye having a spectral sensitivity suitable for the spectral characteristics of a light source of an image setter or a plate making camera can be advantageously selected.

Examples of spectral sensitization to red light include He-Ne
For so-called red light sources such as lasers, red semiconductor lasers and LEDs, the I-1 described in JP-A-54-18726 is used.
Compound of I-38, I-1 to I-35 described in JP-A-6-75322
Compounds and I-1 to I-34 described in JP-A-7-287338
From the dyes 1 to 20 described in JP-B-55-39818, from the compounds I-1 to I-37 described in JP-A-62-284343, and from the compounds described in JP-A-7-287338. The compound of I-34 and the like are advantageously selected.

For semiconductor laser light sources in the wavelength range of 750 to 1400 nm, various known dyes including cyanine, merocyanine, styryl, hemicyanine, oxonol, hemioxonol and xanthene dyes are spectrally advantageously sensitized. Can be done. Useful cyanine dyes are, for example, cyanine dyes having a basic nucleus, such as a thiazoline nucleus, an oxazoline nucleus, a pyrroline nucleus, a pyridine nucleus, an oxazole nucleus, a thiazole nucleus, a selenazole nucleus and an imidazole nucleus. Preferred useful merocyanine dyes include, in addition to the above basic nuclei, acidic nuclei such as thiohydantoin nucleus, rhodanine nucleus, oxazolidinedione nucleus, thiazolinedione nucleus, barbituric acid nucleus, thiazolinone nucleus, malononitrile nucleus and pyrazolone nucleus. Including. Among the above-mentioned cyanine and merocyanine dyes, those having an imino group or a carboxyl group are particularly effective. For example, U.S. Pat.
No. 3,719,495; No. 3,877,943; British Patent No.
Nos. 1,466,201, 1,469,117, 1,422,057,
JP-B-3-10391, JP-B6-52387, JP-A-5-341432,
The dye may be appropriately selected from known dyes as described in JP-A-6-194781 and JP-A-6-301141.

Particularly preferred as the structure of the dye used in the present invention is a cyanine dye having a thioether bond-containing substituent (for example, JP-A Nos. 62-58239 and 3-1386).
No.38, No.3-138642, No.4-255840, No.5-72659, No.
5-72661, 6-222491, 2-230506, 6-258757
No., 6-317868, 6-324425, Tokuyohei 7-500926,
Dyes described in US Pat. No. 5,541,054), dyes having a carboxylic acid group (for example, JP-A-3-163440,
No. 301141, U.S. Pat.No.5,441,899)
, Merocyanine dyes, polynuclear merocyanine dyes and polynuclear cyanine dyes (JP-A-47-6329, JP-A-49-105524, and
-127719, 52-80829, 54-61517, 59-21484
No. 6, No. 60-6750, No. 63-159841, JP-A-6-35109
No. 6-59381, No. 7-46537, No. 7-16537, JP-T 55-50111, UK Patent No. 1,467,638, U.S. Patent No. 5,
No. 281,515).

Further, as dyes forming a J-band, the dyes described in Example 5 of US Pat. Nos. 5,510,236 and 3,871,887, JP-A-2-96131, and JP-A-59-48753 are disclosed. Can be preferably used in the present invention.

These sensitizing dyes may be used alone.
Two or more kinds may be used in combination. Combinations of sensitizing dyes are often used, especially for supersensitization. In addition to the sensitizing dye, the emulsion may contain a dye which does not itself have a spectral sensitizing effect or a substance which does not substantially absorb visible light and exhibits supersensitization. Useful sensitizing dyes, combinations of dyes exhibiting supersensitization and substances exhibiting supersensitization are
Research Disclosure Volume 176 17643 (Issued December 1978) 2
Section J on page 3, IV, or JP-B-49-25500, 43-4933
And JP-A-59-19032 and JP-A-59-192242.

The sensitizing dyes used in the present invention may be used in combination of two or more. To add sensitizing dyes to a silver halide emulsion, they may be directly dispersed in the emulsion,
Or water, methanol, ethanol, propanol,
Acetone, methyl cellosolve, 2,2,3,3-tetrafluoropropanol, 2,2,2-trifluoroethanol, 3-methoxy-1-propanol, 3-methoxy-1-butanol, 1-
It may be dissolved in a solvent such as methoxy-2-propanol or N, N-dimethylformamide alone or in a mixed solvent and added to the emulsion.

As disclosed in US Pat. No. 3,469,987, a dye is dissolved in a volatile organic solvent, and this solution is dispersed in water or a hydrophilic colloid. Method of adding into the inside, Japanese Patent Publication No. 44-23389,
As disclosed in JP-A-44-27555 and JP-A-57-22091, a dye is dissolved in an acid and this solution is added to the emulsion, or an acid or base is added to the emulsion as an aqueous solution in the presence of an acid or base. U.S. Patent Nos. 3,822,135 and 4,006,025
JP-A-53-102733 and JP-A-58-105141 disclose a method of adding an aqueous solution or a colloidal dispersion in the presence of a surfactant to an emulsion as disclosed in JP-A-53-102733 and JP-A-58-105141. A method of directly dispersing a dye in a hydrophilic colloid and adding the dispersion to an emulsion as described in
As disclosed in JP-A-51-74624, a method in which a dye is dissolved using a compound that causes a red shift, and this solution is added to an emulsion can also be used. Also, ultrasonic waves can be used for dissolution.

The sensitizing dye used in the present invention may be added to the silver halide emulsion of the present invention at any time during the preparation of the emulsion which has been found to be useful. For example, U.S. Pat.Nos. 2,735,766 and 3,628,96
No. 4, No. 4,183,756, No. 4,225,666, JP-A-58
As disclosed in the specifications of JP-A-184142 and JP-A-60-196749, chemical ripening is carried out during the step before silver halide grain formation or / and desalination, during the silver removal step and / or after desalination. Before the start of the process, as disclosed in the specification of JP-A-58-113920, etc., immediately before or during the chemical ripening, during the process, after the chemical ripening, until the application of the emulsion is applied. At any time before, it may be added in the process. Also, U.S. Pat.No.4,225,666, JP-A-58-762
As disclosed in the specification of No. 9, etc., the same compound may be used alone or in combination with a compound having a different structure, for example, during the particle formation step and during the chemical ripening step or after the completion of the chemical ripening, The compound may be added in portions such as before aging or during the process and after completion, or may be added by changing the kind of compound to be added and the combination of compounds.

The amount of the sensitizing dye used in the present invention may be a desired amount in accordance with the performance such as sensitivity and fog.
The amount is preferably 10 ^-6 to 1 mol, more preferably 10 ^-4 to 10 ^-1 , per mol of silver halide in the photosensitive layer.

In the present invention, the silver halide emulsion and / or
Alternatively, the organic silver salt can be further protected against the formation of additional fog by antifoggants, stabilizers and stabilizer precursors, and stabilized against reduced sensitivity during storage in inventory. Suitable antifoggants, stabilizers and stabilizer precursors which can be used alone or in combination are the thiazonium salts described in U.S. Pat.Nos. 2,131,038 and 2,694,716, and U.S. Pat.Nos. 2,886,437 and 2,44.
No. 4,605, azaindene, U.S. Pat.No. 2,728,663, mercury salt, U.S. Pat.No. 3,287,135, urazole, U.S. Pat.
Nitroindazole, polyvalent metal salt described in U.S. Pat.No. 2,839,405, thyuronium salt described in U.S. Pat.No.3,220,839, and U.S. Pat.Nos. 2,566,263 and 2,597,915
Palladium, platinum and gold salts described in U.S. Pat.
Halogen-substituted organic compounds described in 8,665 and 4,442,202; U.S. Pat.Nos. 4,128,557 and 4,137,079
No. 4,138,365 and 4,459,350, and the phosphorus compounds described in U.S. Pat. No. 4,411,985.

The antifoggant preferably used in the present invention is an organic halide, for example, as described in JP-A-50-119624.
No. 50-120328, No. 51-121332, No. 54-58022,
56-70543, 56-99335, 59-90842, 61-129
No. 642, No. 62-129845, JP-A-6-208191, No. 7-5621
Nos. 7-2781 and 8-15809; U.S. Patent 5,340,712
No. 5,369,000 and 5,464,737.

The antifoggant of the present invention may be added by any method such as a solution, a powder or a solid fine particle dispersion. The dispersion of the solid fine particles is carried out by a known means for making fine (for example, a ball mill, a vibration ball mill, a sand mill, a colloid mill, a jet mill, a roller mill, etc.). When dispersing the solid fine particles, a dispersing aid may be used.

Although not required to practice the present invention,
It may be advantageous to add a mercury (II) salt as an antifoggant to the emulsion layer. Preferred mercury (II) salts for this purpose are
Mercury acetate and mercury bromide. The amount of mercury used in the present invention is preferably 1 nmol to 1 mmol, more preferably 10 nmol to 100 μm, per 1 mol of coated silver.
Range of moles.

The photothermographic material of the present invention may contain benzoic acids for the purpose of increasing the sensitivity and preventing fog. The benzoic acids of the present invention may be any benzoic acid derivative, but examples of preferred structures include those described in U.S. Pat.
No. 9, No. 4, 152, 160, Japanese Patent Application No. 8-151242, No. 8-151241
And the compounds described in JP-A-8-98051. The benzoic acids of the present invention may be added to any part of the light-sensitive material. However, the added layer is preferably added to a layer having a light-sensitive layer, more preferably to an organic silver salt-containing layer. . The benzoic acid of the present invention may be added in any step of coating solution preparation, and when it is added to an organic silver salt-containing layer, any step from the preparation of organic silver salt to the preparation of coating solution may be used. It is preferable after salt preparation and immediately before application. The benzoic acid of the present invention may be added by any method such as powder, solution, and fine particle dispersion. Further, it may be added as a solution mixed with other additives such as a sensitizing dye, a reducing agent and a color tone agent. The benzoic acid of the present invention may be added in any amount, but is preferably 1 μmol or more and 2 mol or less, more preferably 1 mmol or more and 0.5 mol or less per 1 mol of silver.

In the present invention, a mercapto compound, a disulfide compound, and a thione compound are contained in order to control development by suppressing or accelerating development, to improve spectral sensitization efficiency, and to improve storage stability before and after development. be able to.

When a mercapto compound is used in the present invention, it may be of any structure, but may be any of Ar-SM, Ar-SSA
Those represented by r are preferred. In the formula, M is a hydrogen atom or an alkali metal atom, and Ar is an aromatic or fused aromatic ring group having one or more nitrogen, sulfur, oxygen, selenium or tellurium atoms. Preferably, the heteroaromatic ring in such a group is benzimidazole, naphthimidazole, benzothiazole, naphthothiazole, benzoxazole, naphthoxazole, benzoselenazole, benzotellazole, imidazole, oxazole, pyrazole, triazole, thiadiazole, tetrazole, triazine, Pyrimidine, pyridazine, pyrazine, pyridine, purine, quinoline or quinazolinone. Such heteroaromatic rings include, for example, halogens (eg, Br and Cl), hydroxy, amino,
Carboxy, alkyl (eg, one or more carbon atoms,
Preferably those having 1 to 4 carbon atoms and alkoxy (for example one or more carbon atoms, preferably 1 to 4 carbon atoms).
) May be selected from the substituent group consisting of those having from 4 to 4 carbon atoms). As mercapto-substituted heteroaromatic compounds, 2-mercaptobenzimidazole, 2-mercaptobenzoxazole, 2-mercaptobenzothiazole, 2-mercapto-5-methylbenzimidazole, 6-ethoxy-2-mercaptobenzothiazole,
2,2'-dithiobis-benzothiazole, 3-mercapto-
1,2,4-triazole, 4,5-diphenyl-2-imidazole thiol, 2-mercaptoimidazole, 1-ethyl-2-
Mercaptobenzimidazole, 2-mercaptoquinoline, 8-mercaptopurine, 2-mercapto-4 (3H) -quinazolinone, 7-trifluoromethyl-4-quinolinethiol,
2,3,5,6-tetrachloro-4-pyridinethiol, 4-amino
-6-hydroxy-2-mercaptopyrimidine monohydrate, 2-amino-5-mercapto-1,3,4-thiadiazole,
3-Amino-5-mercapto-1,2,4-triazole, 4-hydrochiroxy-2-mercaptopyrimidine, 2-mercaptopyrimidine, 4,6-diamino-2-mercaptopyrimidine, 2-mercapto-4-methylpyrimidinehydro Chloride, 3-mercapto-5-phenyl-1,2,4-triazole, 2-mercapto
-4-phenyloxazole and the like, but the present invention is not limited to these.

The addition amount of these mercapto compounds is preferably in the range of 0.001 to 1.0 mol per mol of silver in the emulsion layer, more preferably 0.01 to 1.0 mol per mol of silver.
The amount is 0.3 mol.

In the photosensitive layer of the present invention, a polyhydric alcohol (for example, US Pat.
Glycerin and diols of the type described in U.S. Pat. No. 0,404), fatty acids or esters described in U.S. Pat. Nos. 2,588,765 and 3,121,060, and silicone resins described in British Patent No. 955,061.

In the photothermographic material of the present invention, the following formulas (A) to (C) are used as a super-high contrast agent for forming a super-high contrast image.
A substituted alkene derivative, a substituted isoxazole derivative and a specific acetal compound represented by the following formula (1) can be used. Formulas (A), (B), and (C) will be described.

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In the formula (A), R ¹ , R ² and R ³ each independently represent a hydrogen atom or a substituent, and Z represents an electron-withdrawing group or a silyl group. In the formula (A), R ¹ and Z, R ² and R ³ , R ¹ and R ² , or R ³ and Z may be bonded to each other to form a cyclic structure. Formula (B)
In the above, R ⁴ represents a substituent. In the formula (C), X,
Y each independently represents a hydrogen atom or a substituent;
B is each independently an alkoxy group, an alkylthio group,
Alkylamino group, aryloxy group, arylthio group, anilino group, heterocyclic oxy group, heterocyclic thio group,
Or a heterocyclic amino group. In the formula (C), X and Y or A and B may be bonded to each other to form a cyclic structure.

The compound represented by the formula (A) will be described in detail.

In the formula (A), R ¹ , R ² and R ³ each independently represent a hydrogen atom or a substituent, and Z represents an electron-withdrawing group or a silyl group. In the formula (A), R ¹ and Z, R ² and R ³ , R ¹ and R ² , or R ³ and Z may be bonded to each other to form a cyclic structure.

When R ¹ , R ² , and R ³ represent a substituent, examples of the substituent include a halogen atom (a fluorine atom, a chlorine atom, a bromine atom, or an iodine atom) and an alkyl group (an aralkyl group, a cycloalkyl group). An alkyl group, an active methine group, etc.), an alkenyl group, an alkynyl group, an aryl group, a heterocyclic group (including an N-substituted nitrogen-containing heterocyclic group), and a heterocyclic group containing a quaternized nitrogen atom ( For example, a pyridinio group), an acyl group, an alkoxycarbonyl group, an aryloxycarbonyl group, a carbamoyl group, a carboxy group or a salt thereof, an imino group, an imino group substituted with an N atom, a thiocarbonyl group, a sulfonylcarbamoyl group, an acylcarbamoyl group, Famoylcarbamoyl group, carbazoyl group, oxalyl group, oxamoyl group, cyano group, thiocarbamoyl group, A droxy group or a salt thereof, an alkoxy group (including a group repeatedly containing an ethyleneoxy group or a propyleneoxy group unit), an aryloxy group, a heterocyclic oxy group, an acyloxy group, an (alkoxy or aryloxy) carbonyloxy group, and a carbamoyloxy group , Sulfonyloxy group, amino group, (alkyl, aryl or heterocycle) amino group, acylamino group, sulfonamide group, ureido group, thioureido group, imide group, (alkoxy or aryloxy)
Carbonylamino group, sulfamoylamino group, semicarbazide group, thiosemicarbazide group, hydrazino group, 4
Grade ammonio group, oxamoylamino group, (alkyl or aryl) sulfonyluureido group, acylureido group, acylsulfamoylamino group, nitro group, mercapto group, (alkyl, aryl, or heterocycle)
Thio group, acylthio group, (alkyl or aryl) sulfonyl group, (alkyl or aryl) sulfinyl group, sulfo group or a salt thereof, sulfamoyl group, acylsulfamoyl group, sulfonylsulfamoyl group or a salt thereof, phosphoryl group, phosphorus Examples include groups having an acid amide or phosphate structure, silyl groups, stannyl groups, and the like.

These substituents may be further substituted with these substituents.

The electron-withdrawing group represented by Z in the formula (A) is a substituent whose Hammett's substituent constant σ _p can take a positive value, specifically, a cyano group, an alkoxy group or an alkoxy group. Carbonyl group, aryloxycarbonyl group, carbamoyl group, imino group, imino group substituted with an N atom, thiocarbonyl group, sulfamoyl group, alkylsulfonyl group, arylsulfonyl group, nitro group, halogen atom,
A perfluoroalkyl group, a perfluoroalkaneamide group, a sulfonamide group, an acyl group, a formyl group, a phosphoryl group, a carboxy group (or a salt thereof), a sulfo group (or a salt thereof), a heterocyclic group, an alkenyl group, an alkynyl group, Examples include an acyloxy group, an acylthio group, a sulfonyloxy group, and an aryl group substituted with these electron-withdrawing groups. Here, the heterocyclic group is a saturated or unsaturated heterocyclic group, for example, a pyridyl group, a quinolyl group,
Examples thereof include a quinoxalinyl group, a pyrazinyl group, a benzotriazolyl group, an imidazolyl group, a benzimidazolyl group, a hydantoin-1-yl group, a succinimide group, and a phthalimido group.

The electron-withdrawing group represented by Z in the formula (A) may further have a substituent. As the substituent, R ¹ , R ² and R ^{3 in the} formula (A) The same substituents as the substituents that may be present when representing the substituents are exemplified.

In the formula (A), R ¹ and Z, R ² and R ³ ,
R ¹ and R ² , or R ³ and Z may be bonded to each other to form a cyclic structure, and the cyclic structure formed at this time is a non-aromatic carbon ring or a non-aromatic heterocycle. Is a ring.

Next, the preferred range of the compound represented by the formula (A) will be described.

In the formula (A), the silyl group represented by Z is preferably a trimethylsilyl group, a t-butyldimethylsilyl group, a phenyldimethylsilyl group, a triethylsilyl group, a triisopropylsilyl group, a trimethylsilyldimethylsilyl group. And so on.

The electron-withdrawing group represented by Z in the formula (A) is preferably a group having a total number of carbon atoms of 0 to 30, that is, a cyano group, an alkoxycarbonyl group, an aryloxycarbonyl group, a carbamoyl group, Carbonyl group,
Imino group, imino group substituted with N atom, sulfamoyl group, alkylsulfonyl group, arylsulfonyl group, nitro group, perfluoroalkyl group, acyl group, formyl group, phosphoryl group, acyloxy group, acylthio group, or any electron withdrawing And a phenyl group substituted with a functional group, more preferably a cyano group, an alkoxycarbonyl group, a carbamoyl group, an imino group, a sulfamoyl group,
An alkylsulfonyl group, an arylsulfonyl group, an acyl group, a formyl group, a phosphoryl group, a trifluoromethyl group, or a phenyl group substituted with any electron-withdrawing group, and particularly preferably a cyano group, a formyl group, an acyl group. , An alkoxycarbonyl group, an imino group or a carbamoyl group.

The group represented by Z in the formula (A) is more preferably an electron-withdrawing group.

In the formula (A), R ¹ , R ² and R ³
The substituent represented by preferably has a total carbon number of 0 to 30.
Specifically, a group having the same meaning as the electron-withdrawing group represented by Z in the above formula (A), and an alkyl group or a hydroxy group
(Or its salt), mercapto group (or its salt), alkoxy group, aryloxy group, heterocyclic oxy group, alkylthio group, arylthio group, heterocyclic thio group, amino group, alkylamino group, arylamino group, heterocyclic group Examples include an amino group, a ureido group, an acylamino group, a sulfonamide group, and a substituted or unsubstituted aryl group.

Further, in the formula (A), R ¹ is preferably an electron-withdrawing group, an aryl group, an alkylthio group, an alkoxy group, an acylamino group, a hydrogen atom or a silyl group.

When R ¹ represents an electron-withdrawing group, it is preferably a group having the following total number of carbon atoms, that is, a cyano group, a nitro group, an acyl group, a formyl group, an alkoxycarbonyl group,
An aryloxycarbonyl group, a thiocarbonyl group, an imino group, an imino group substituted with an N atom, an alkylsulfonyl group, an arylsulfonyl group, a carbamoyl group, a sulfamoyl group, a trifluoromethyl group, a phosphoryl group, a carboxy group (or a salt thereof), Or a saturated or unsaturated heterocyclic group, and a cyano group, an acyl group, a formyl group, an alkoxycarbonyl group, a carbamoyl group, an imino group, an imino group substituted with an N atom, a sulfamoyl group, a carboxy group (or a salt thereof) Or a saturated or unsaturated heterocyclic group. Particularly preferred are a cyano group, a formyl group, an acyl group, an alkoxycarbonyl group, a carbamoyl group, and a saturated or unsaturated heterocyclic group.

When R ¹ represents an aryl group, it is preferably a substituted or unsubstituted phenyl group having a total of 6 to 30 carbon atoms. Examples of the substituent include any substituent.
Among them, an electron-withdrawing substituent is preferable.

In formula (A), R ¹ is more preferably an electron-withdrawing group or an aryl group.

In the formula (A), the substituents represented by R ² and R ³ are preferably specific examples of the above-mentioned formula (A)
A group having the same meaning as the electron-withdrawing group represented by Z, an alkyl group,
Hydroxy group (or salt thereof), mercapto group (or salt thereof), alkoxy group, aryloxy group, heterocyclic oxy group, alkylthio group, arylthio group, heterocyclic thio group, amino group, alkylamino group, anilino group, hetero group Examples include a cyclic amino group, an acylamino group, and a substituted or unsubstituted phenyl group.

In formula (A), R ² and R ³ are more preferably when one of them is a hydrogen atom and the other is a substituent. Preferably, the substituent is an alkyl group, a hydroxy group (or a salt thereof), a mercapto group
(Or salt thereof), an alkoxy group, an aryloxy group,
Heterocyclic oxy group, alkylthio group, arylthio group,
A heterocyclic thio group, an amino group, an alkylamino group, an anilino group, a heterocyclic amino group, an acylamino group (particularly a perfluoroalkaneamide group), a sulfonamide group, a substituted or unsubstituted phenyl group, or a heterocyclic group; , More preferably a hydroxy group (or a salt thereof),
A mercapto group (or a salt thereof), an alkoxy group, an aryloxy group, a heterocyclic oxy group, an alkylthio group, an arylthio group, a heterocyclic thio group, or a heterocyclic group, particularly preferably a hydroxy group (or a salt thereof), Or a heterocyclic group.

In the formula (A), it is also preferable that Z and R ¹ , or R ² and R ³ form a cyclic structure. The cyclic structure formed in this case is a non-aromatic carbocyclic or non-aromatic heterocyclic ring, preferably a 5- to 7-membered cyclic structure having a total carbon number of 1 including a substituent.
To 40, more preferably 3 to 30.

Among the compounds represented by the formula (A), one of the more preferable ones is that Z represents a cyano group, a formyl group, an acyl group, an alkoxycarbonyl group, an imino group or a carbamoyl group, and R ¹ is Represents an electron-withdrawing group or an aryl group, wherein one of R ^{2 and} R ³ is a hydrogen atom and the other is a hydroxy group (or a salt thereof), a mercapto group (or a salt thereof), an alkoxy group, an aryloxy group, The compound represents a ring oxy group, an alkylthio group, an arylthio group, a heterocyclic thio group, or a heterocyclic group.

Further, one of the particularly preferable compounds represented by the formula (A) is that Z and R ^{1 form a} non-aromatic 5- to 7-membered cyclic structure, and R ² Or R ³
Is a hydrogen atom, the other is a hydroxy group (or a salt thereof), a mercapto group (or a salt thereof), an alkoxy group, an aryloxy group, a heterocyclic oxy group, an alkylthio group, an arylthio group, a heterocyclic thio group, Or a compound representing a heterocyclic group. At this time, Z which forms a non-aromatic cyclic structure together with R ¹ includes an acyl group, a carbamoyl group, an oxycarbonyl group, a thiocarbonyl group,
A sulfonyl group and the like are preferable, and R ¹ is preferably an acyl group, a carbamoyl group, an oxycarbonyl group, a thiocarbonyl group, a sulfonyl group, an imino group, an imino group substituted by an N atom, an acylamino group, a carbonylthio group, and the like.

Next, the compound represented by the formula (B) will be described.

As the substituent represented by R ⁴ in the formula (B), the same substituents as described for the substituents R ^{1 to} R ^{3 in} the formula (A) can be mentioned.

The substituent represented by R ⁴ in the formula (B) is preferably an electron-withdrawing group or an aryl group.
When R ⁴ represents an electron-withdrawing group, it preferably has a total carbon number of 0.
To 30 or less of the following groups: cyano group, nitro group, acyl group, formyl group, alkoxycarbonyl group, aryloxycarbonyl group, alkylsulfonyl group, arylsulfonyl group, carbamoyl group, sulfamoyl group, trifluoromethyl group, phosphoryl Group, imino group, or a saturated or unsaturated heterocyclic group, and further a cyano group, an acyl group, a formyl group, an alkoxycarbonyl group,
A carbamoyl group, a sulfamoyl group, an alkylsulfonyl group, an arylsulfonyl group, and a heterocyclic group are preferred.
Particularly preferred are a cyano group, a formyl group, an acyl group, an alkoxycarbonyl group, a carbamoyl group, and a heterocyclic group.

When R ⁴ represents an aryl group, it is preferably a substituted or unsubstituted phenyl group having a total of 0 to 30 carbon atoms, and the substituent is represented by R ¹ , R ² , R ^{3 of} formula (A). When represents a substituent, the same as those described as the substituent can be mentioned.

In the formula (B), R ⁴ is particularly preferably a cyano group, an alkoxycarbonyl group, a carbamoyl group,
A heterocyclic group or a substituted or unsubstituted phenyl group, most preferably a cyano group, a heterocyclic group, or an alkoxycarbonyl group.

Next, the compound represented by the formula (C) will be described in detail.

In the formula (C), X and Y each independently represent a hydrogen atom or a substituent, and A and B each independently represent an alkoxy group, an alkylthio group, an alkylamino group, an aryloxy group, an arylthio group, an anilino group. ,
Represents a heterocyclic thio group, a heterocyclic oxy group, or a heterocyclic amino group. X and Y or A and B may be bonded to each other to form a cyclic structure.

The substituents represented by X and Y in the formula (C) include the same substituents as those described for the substituents R ^{1 to} R ^{3 in} the formula (A). Specifically, alkyl groups (including perfluoroalkyl groups, trichloromethyl groups, etc.), aryl groups, heterocyclic groups, halogen atoms, cyano groups, nitro groups, alkenyl groups, alkynyl groups, acyl groups, formyl groups, alkoxy groups Carbonyl group, aryloxycarbonyl group, imino group, imino group substituted with an N atom, carbamoyl group, thiocarbonyl group, acyloxy group, acylthio group, acylamino group, alkylsulfonyl group, arylsulfonyl group, sulfamoyl group, phosphoryl group, carboxy Group (or its salt), sulfo group (or its salt), hydroxy group (or its salt), mercapto group (or its salt), alkoxy group, aryloxy group, heterocyclic oxy group, alkylthio group, arylthio group, hetero group Ring thio group, amino group, alkylami Group, anilino group, heterocyclic amino group, a silyl group, and the like.

These groups may further have a substituent. X and Y may be bonded to each other to form a cyclic structure, and the cyclic structure formed in this case may be a non-aromatic carbon ring or a non-aromatic hetero ring. .

The substituent represented by X and Y in the formula (C) is preferably a group having 1 to 40 carbon atoms in total, more preferably a group having 1 to 30 carbon atoms in total, and is a cyano group, an alkoxycarbonyl group, Aryloxycarbonyl group, carbamoyl group, imino group, imino group substituted with N atom, thiocarbonyl group, sulfamoyl group, alkylsulfonyl group, arylsulfonyl group, nitro group, perfluoroalkyl group, acyl group, formyl group, phosphoryl group , An acylamino group, an acyloxy group, an acylthio group, a heterocyclic group, an alkylthio group, an alkoxy group, or an aryl group.

In the formula (C), X and Y are more preferably cyano, nitro, alkoxycarbonyl, carbamoyl, acyl, formyl, acylthio, acylamino, thiocarbonyl, sulfamoyl,
An alkylsulfonyl group, an arylsulfonyl group, an imino group, an imino group substituted with an N atom, a phosphoryl group, a trifluoromethyl group, a heterocyclic group, or a substituted phenyl group, and particularly preferably a cyano group or an alkoxycarbonyl group , A carbamoyl group, an alkylsulfonyl group,
An arylsulfonyl group, an acyl group, an acylthio group, an acylamino group, a thiocarbonyl group, a formyl group, an imino group, an imino group substituted with an N atom, a heterocyclic group, or a phenyl group substituted with any electron-withdrawing group; is there.

It is also preferable that X and Y combine with each other to form a non-aromatic carbon ring or a non-aromatic hetero ring. At this time, the formed cyclic structure is preferably a 5- to 7-membered ring, and has a total carbon number of 1 to 40, more preferably 3 to
30 is preferred. X and Y forming a cyclic structure include an acyl group, a carbamoyl group, an oxycarbonyl group,
Preferred are a thiocarbonyl group, a sulfonyl group, an imino group, an imino group substituted with an N atom, an acylamino group, a carbonylthio group and the like.

In the formula (C), A and B each independently represent an alkoxy group, an alkylthio group, an alkylamino group, an aryloxy group, an arylthio group, an anilino group,
Represents a heterocyclic thio group, a heterocyclic oxy group, or a heterocyclic amino group, which may be bonded to each other to form a cyclic structure.

In the formula (C), the groups represented by A and B are
It is preferably a group having a total of 1 to 40 carbon atoms, more preferably a group having a total of 1 to 30 carbon atoms, and may further have a substituent.

In the formula (C), A and B are
More preferably when they are linked to
No. The cyclic structure formed at this time is a 5- to 7-membered non-aromatic ring
Group heterocycles are preferred, having a total carbon number of 1 to 40,
These are preferably 3 to 30. In this case, A and B are connected
The example (-AB-) described above is, for example, -O- (CH
_Two)_Two-O-, -O- (CH_Two)_Three-O-, -S- (C
H_Two)_Two-S-, -S- (CH_Two)_Three-S-, -S-p
h-S-, -N (CH_Three)-(CH_Two)_Two-O-, -N
(CH_Three)-(CH_Two)_Two-S-, -O- (CH_Two)_Two
-S-, -O- (CH_Two)_Three-S-, -N (CH_Three)-
ph-O-, -N (CH_Three) -Ph-S-,-N (p
h)-(CH_Two)_Two-S- and so on.

The compounds represented by the formulas (A) to (C) used in the present invention may have incorporated therein an adsorptive group that adsorbs to silver halide. Such adsorbing groups include alkylthio, arylthio, thiourea,
U.S. Pat. Nos. 4,385,108 and 4,459, such as thioamide group, mercapto heterocyclic group and triazole group;
347, JP-A-59-195233, and JP-A-59-20
Nos. 0231, 59-201045, 59-201
Nos. 046, 59-201047, 59-2010
No. 48, 59-201049, JP-A-61-170
No. 733, No. 61-270744, No. 62-948
Nos. 63-234244 and 63-234245
And groups described in JP-A-63-234246. These adsorbing groups to silver halide may be precursors. Examples of such a precursor include the groups described in JP-A-2-285344.

The compounds represented by the formulas (A) to (C) used in the present invention have incorporated therein a ballast group or a polymer commonly used in immobile photographic additives such as couplers. It may be something. Particularly, those incorporating a ballast group are one of preferred examples of the present invention. The ballast group is a group having a carbon number of 8 or more and relatively inactive to photographic properties, such as an alkyl group, an aralkyl group, an alkoxy group, a phenyl group, an alkylphenyl group, a phenoxy group, and an alkylphenoxy group. You can choose from. Examples of the polymer include those described in JP-A-1-100530.

The compounds represented by the formulas (A) to (C) used in the present invention contain a cationic group (specifically, a group containing a quaternary ammonium group, or a quaternized group). A nitrogen-containing heterocyclic group containing a nitrogen atom), a group containing a repeating unit of an ethyleneoxy group or a propyleneoxy group, an (alkyl, aryl, or heterocyclic) thio group,
Alternatively, it may contain a dissociable group (such as a carboxy group, a sulfo group, an acylsulfamoyl group, or a carbamoylsulfamoyl group) that can be dissociated by a base. Particularly, a group containing a group containing a repeating unit of an ethyleneoxy group or a propyleneoxy group or a group containing an (alkyl, aryl, or heterocyclic) thio group is one of preferred examples of the present invention. Specific examples of these groups include, for example, JP-A-7-234471 and JP-A-5-333466.
JP-A-6-19032, JP-A-6-19031
JP-A-5-45761, U.S. Pat. No. 4,994,365.
No. 4,988,604, JP-A-3-25924.
No. 0, JP-A-7-5610, JP-A-7-244348
And the compounds described in German Patent No. 4006032.

Next, specific examples of the compounds represented by the formulas (A) to (C) used in the present invention are shown below. However, the present invention is not limited to the following compounds.

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The compounds represented by the formulas (A) to (C) used in the present invention may be water or a suitable organic solvent such as alcohols (methanol, ethanol, propanol,
It can be used by dissolving in fluorinated alcohol), ketones (acetone, methyl ethyl ketone), dimethylformamide, dimethylsulfoxide, methylcellosolve and the like.

Further, by a well-known emulsification dispersion method, an oil such as dibutyl phthalate, tricresyl phosphate, glyceryl triacetate or diethyl phthalate or an auxiliary solvent such as ethyl acetate or cyclohexanone is used for dissolution, An emulsified dispersion can be prepared and used. Alternatively, by a method known as a solid dispersion method, the powder of the compound represented by Formulas (A) to (C) of the present invention is dispersed in a suitable solvent such as water by a ball mill, a colloid mill, or ultrasonic waves. Can be used.

The compounds represented by the formulas (A) to (C) used in the present invention may be used in combination with a layer on an image forming layer side with respect to a support,
That is, it may be added to the image forming layer or any other layer on the layer side, but is preferably added to the image forming layer or a layer adjacent thereto.

The addition amount of the compounds represented by the formulas (A) to (C) of the present invention is preferably 1 × 10 ^-6 to 1 mol per 1 mol of silver, and 1 × 10 ^{-5 to} 5 × 10 5 ^-1 mol is more preferred, and 2 × 10 ^-5 to 2 × 10 ^-1 mol is most preferred.

The compounds represented by the formulas (A) to (C) can be easily synthesized by known methods. For example, US Pat. No. 5,545,515 and US Pat.
No. 9, U.S. Pat. No. 5,654,130, International Patent WO-97
/ 34196, or Japanese Patent Application No. 9-354107.
The compounds can be synthesized with reference to the methods described in Japanese Patent Application Nos. 9-309813 and 9-272002.

The compounds represented by the formulas (A) to (C) used in the present invention may be used alone or in combination of two or more. Also, in addition to the above, US Pat.
No. 515, US Pat. No. 5,635,339, US Pat.
No. 4,130, International Patent WO-97 / 34196, compounds described in U.S. Pat. No. 5,686,228, or Japanese Patent Application Nos. 8-279962 and 9-228881;
Japanese Patent Application No. 9-273935, Japanese Patent Application No. 9-354107
No., Japanese Patent Application No. 9-309813, Japanese Patent Application No. 9-29617
4, Japanese Patent Application No. 9-282564, Japanese Patent Application No. 9-2720
02, Japanese Patent Application No. 9-272003, Japanese Patent Application No. 9-332
No. 388 may be used in combination.

Further, in the present invention, Japanese Patent Application No. 9-16 / 1990
No. 6628, Japanese Patent Application No. 8-279957, Japanese Patent Application No. 9-2
The hydrazine derivatives described in No. 40511 can also be used in combination. Further, the following hydrazine derivatives can be used in combination. That is,
A compound represented by (Chemical Formula 1) described in No. 77138, specifically, a compound described on pages 3 and 4 of the same publication. Tokuhei 6-
Compounds represented by the general formula (I) described in No. 93082, specifically, compounds 1 to 38 described on pages 8 to 18 of the same publication. Compounds represented by formulas (4), (5) and (6) described in JP-A-6-230497, specifically, compound 4- described on pages 25 and 26 of the same publication. 1 to 4-10, compounds 5-1 to 5-42 described on pages 28 to 36, and compounds 6-1 to 6-7 described on pages 39 and 40. JP-A-6-289520
Compounds represented by the general formulas (1) and (2) described in the above publications, specifically, the compounds 1-1) to 1-17) and 2-1 described on pages 5 to 7 of the same publication. ). JP-A-6-31
Compounds represented by (Chemical Formula 2) and (Chemical Formula 3) described in No. 3936, specifically, compounds described on pages 6 to 19 of the same publication. Compounds represented by (Chemical Formula 1) described in JP-A-6-313951, specifically, compounds described on pages 3 to 5 of the same. Compounds represented by formula (I) described in JP-A-7-5610, specifically, compounds I-1 to I-38 described on pages 5 to 10 of the same. Compounds represented by general formula (II) described in JP-A-7-77783, specifically, compounds II-1 to II-10 described on pages 10 to 27 of the same publication
2. Compounds represented by formulas (H) and (Ha) described in JP-A-7-104426, specifically, compounds H-1 to H-44 described on pages 8 to 15 of the same publication. A compound described in EP 713131A, which has an anionic group or a nonionic group that forms an intramolecular hydrogen bond with a hydrogen atom of hydrazine in the vicinity of a hydrazine group. Particularly, a compound represented by the general formula (A): A compound represented by the formula (B), the general formula (C), the general formula (D), the general formula (E), or the general formula (F).
-1 to N-30. Compounds represented by the general formula (1) described in European Patent 713131A, and specifically, compounds D-1 to D-55 described in the publication.

Further, “Known Techniques (1.
Pp. 207) ”(published by Aztec) on pages 25 to 34. JP-A-62-2635
Compounds D-2 and D-39 of No. 4 (pages 6 to 7).

These hydrazine derivatives are dissolved in water or a suitable organic solvent such as alcohols (methanol, ethanol, propanol, fluorinated alcohol), ketones (acetone, methyl ethyl ketone), dimethylformamide, dimethyl sulfoxide, methylcellosolve, etc. Can be used.

Further, by a well-known emulsification and dispersion method, an oil such as dibutyl phthalate, tricresyl phosphate, glyceryl triacetate or diethyl phthalate, or an auxiliary solvent such as ethyl acetate or cyclohexanone is used to dissolve and dissolve. An emulsified dispersion can be prepared and used. Alternatively, a powder of a hydrazine derivative can be dispersed in water by a ball mill, a colloid mill, or an ultrasonic wave by a method known as a solid dispersion method and used.

These hydrazine derivatives may be added to the layer on the image forming layer side with respect to the support, that is, to the image forming layer or any other layer on the layer side. It is preferred to add.

The amount of these hydrazine derivatives to be added is preferably 1 × 10 ⁻⁶ to 1 mol per 1 mol of silver, and 1 × 10 ⁻⁵ to 1 × 10 ⁻⁵ .
5 × 10 ^-1 mol is more preferred, and 2 × 10 ^-5 to 2 × 10
^-1 mole is most preferred.

The acrylonitriles described in US Pat. No. 5,545,515, specifically, CN-1 to CN-13 and the like can be used as a super-high contrast agent.

Further, the present invention provides a method for forming a super-high contrast image.
A high contrast accelerator can be used in combination with the above-mentioned super-high contrast agent. For example, the amine compounds described in U.S. Patent No. 5,545,505, specifically AM-1 to AM-5, and 5,545,507
, Specifically HA-1 to HA
No. 5,558,983, specifically, CA-1 to CA-6, and onium salts described in Japanese Patent Application No. 8-132836, specifically A-1 to A. -42, B-1 ~
B-27 and C-1 to C-14 can be used.

The method for synthesizing, adding, and adding amounts of the above-mentioned super-high contrast agent and these high-contrast accelerators can be carried out as described in each of the cited patents.

The light-sensitive material of the present invention can be provided with a surface protective layer for the purpose of preventing adhesion of the image forming layer.
Any anti-adhesion material may be used as the surface protective layer. Examples of anti-adhesion materials include waxes, silica particles, styrene-containing elastomeric block copolymers (eg, styrene-butadiene-styrene, styrene
-Isoprene-styrene), cellulose acetate, cellulose acetate butyrate, cellulose propionate and mixtures thereof.

In the emulsion layer or the protective layer of the emulsion layer in the present invention, in addition to the colored layer of the present invention, or when these layers are the colored layers of the present invention, a combination of US Pat.
Nos. 921, 2,274,782, 2,527,583 and 2,95
Light absorbing materials and filter dyes as described in 6,879 can be used. Further, a dye can be mordant as described in, for example, US Pat. No. 3,282,699. The amount of the filter dye used is preferably from 0.1 to 3 at the exposure wavelength, particularly preferably from 0.2 to 1.5.

In the emulsion layer or the protective layer of the emulsion layer in the present invention, a matting agent such as starch, titanium dioxide, zinc oxide, silica, US Pat. Nos. 2,992,101 and 2,701,
Polymer beads, including beads of the type described in No. 245, can be included. The matte degree of the emulsion surface may be any value as long as stardust failure does not occur, but the Beck smoothness is preferably 200 seconds or more and 10,000 seconds or less, particularly 30 seconds.
It is preferably from 0 seconds to 10,000 seconds.

The photothermographic emulsion of the present invention is contained in one or more layers provided on a support. One layer must include the organic silver salt, silver halide, developer (reducing agent) and binder, and optional additional materials such as toning agents, coating aids and other auxiliaries. The two-layer construction is that the first emulsion layer (usually the layer adjacent to the support) contains an organic silver salt and silver halide, and the second layer or both layers do not contain some other components. No. However, a two-layer construction comprising a single emulsion layer containing all components and a protective topcoat is also contemplated. The construction of the multicolor photothermographic material may include a combination of these two layers for each color, and US Pat. No. 4,708,92
As described in No. 8, all components may be contained in a single layer. In the case of multi-dye, multi-color light-sensitive photothermographic materials, each emulsion layer generally employs a functional or non-functional barrier layer between the emulsion layers as described in U.S. Pat. No. 4,460,681. Thereby, they are kept distinct from each other. .

The photosensitive layer of the present invention may be an irradiation prevention layer at the same time. Further, the photosensitive layer of the present invention can contain various dyes from the viewpoint of improving color tone and preventing irradiation. These photosensitive layers may be the colored layers of the present invention, may not contain the photoradical generator of the present invention, and may further include these layers. The dye used in the photosensitive layer of the present invention may be any dye, for example, pyrazoloazole dye, anthraquinone dye, azo dye, azomethine dye, oxonol dye, carbocyanine dye, styryl dye, triphenylmethane dye, indoaniline dye,
And indophenol dyes. Preferred dyes used in the present invention include anthraquinone dyes (for example, compounds 1 to 9 described in JP-A-5-341441, JP-A-5-1651).
No. 47, such as compounds 3-6 to 18 and 3-23 to 38), azomethine dyes (such as compounds 17 to 47 described in JP-A-5-341441), and indoaniline dyes (e.g., those described in JP-A-5-289227). Compounds 11 to 19, compound 47 described in JP-A-5-341441,
And azo dyes (compounds 10 to 16 described in JP-A-5-341441). As a method for adding these dyes, any method such as a solution, an emulsion, a solid fine particle dispersion, and a state in which the dye is mordanted with a polymer mordant may be used. The amount of these compounds used is determined depending on the desired absorption amount, but it is generally preferable to use them in an amount of 1 μg or more and 1 g or less per 1 m ² of the photographic material.

In the present invention, the antihalation layer can be provided on the side farther from the light source than the photosensitive layer.
The antihalation layer has a maximum absorption in the desired wavelength range.
It is preferably 0.3 or more and 2 or less, more preferably absorption at an exposure wavelength of 0.5 or more and 2 or less, and absorption in the visible region after processing is preferably 0.001 or more and less than 0.5, and more preferably 0.001 or more. It is preferable that the layer has an optical density of less than 0.3, particularly preferably 0.001 or more and 0.1 or less. In the present invention, an antihalation layer can be provided as a separate layer from the colored layer of the present invention. The antihalation dye used in the layer may be any compound as long as it has the desired absorption in the wavelength range, has a sufficiently low absorption in the visible region after the treatment, and has a desirable absorbance spectrum of the antihalation layer. For example, the following are disclosed, but the present invention is not limited thereto. As a single dye, JP-A-59-56458, JP-A-2-216140, 7-13295
No. 7,114,432, U.S. Pat.
JP-A No. 2-68539, page 13, lower left column, line 1 to page 14, lower left column, line 9; JP-A-3-24539, page 14, lower left column, page 16, lower right column Dyes decolorized in JP-A-52-139136, JP-A-53-132334, JP-A-56-501480
No. 57-16060, No. 57-68831, No. 57-101835, No.
59-182436, JP-A-7-36145, JP-A-7-199409, JP-B-48-33692, JP-B-50-16648, JP-B-2-41734, U.S. Patents 4,088,497, 4,283,487, 4,548,896 ,
No. 5,187,049. When the coloring layer of the present invention is an antihalation layer, the above dye may be used in combination.

The photothermographic material according to the invention has a support having at least one light-sensitive layer (emulsion layer) containing a silver halide emulsion on one side and a back layer on the other side. It is preferably a single-sided photosensitive material.

In the present invention, a matting agent may be added to the single-sided photosensitive material in order to improve transportability. The matting agent is generally fine particles of an organic or inorganic compound insoluble in water. Any matting agent can be used, for example, U.S. Patent Nos. 1,939,213, 2,701,245, and 2,322,037.
No. 3,262,782, No. 3,539,344, No. 3,767,448, etc.
No. 2,192,241, No. 3,257,206, No. 3,370,951, No.
Inorganic matting agents well-known in the art, such as inorganic matting agents described in the specifications such as 3,523,022 and 3,769,020 can be used. For example, specific examples of organic compounds that can be used as a matting agent include polymethyl acrylate, polymethyl methacrylate, polyacrylonitrile, and acrylonitrile as examples of water-dispersible vinyl polymers.
-α-methylstyrene copolymer, polystyrene, styrene-divinylbenzene copolymer, polyvinyl acetate, polyethylene carbonate, polytetrafluoroethylene, etc.Examples of cellulose derivatives such as methylcellulose, cellulose acetate, cellulose acetate propionate, etc. Examples of the derivative preferably include carboxystarch, carboxynitrophenyl starch, urea-formaldehyde-starch reactant, and the like, gelatin hardened with a known hardener, hardened gelatin coacervated and hardened into fine capsule hollow granules, and the like. Examples of inorganic compounds include silicon dioxide, titanium dioxide, magnesium dioxide, aluminum oxide, barium sulfate, calcium carbonate, silver chloride desensitized by known methods,
Similarly, silver bromide, glass, diatomaceous earth and the like can be preferably used. The above matting agents can be used by mixing different types of substances as necessary. The size and shape of the matting agent are not particularly limited, and those having an arbitrary particle size can be used. In the practice of the present invention, 0.1 μm to 30 μm
It is preferable to use one having a particle size of m. Further, the particle size distribution of the matting agent may be narrow or wide. On the other hand, since the matting agent greatly affects the haze and surface gloss of the photosensitive material, the particle size, shape, and particle size distribution can be adjusted as needed during the preparation of the matting agent or by mixing a plurality of matting agents. preferable.

In the present invention, the matte degree of the back layer is preferably such that the Bekk smoothness is 250 seconds or less and 10 seconds or more, and more preferably 180 seconds or less and 50 seconds or more.

In the present invention, the matting agent is preferably contained in the outermost surface layer of the light-sensitive material, a layer functioning as the outermost surface layer, or a layer close to the outer surface. It is preferable to be contained.

In the present invention, suitable binders for the back layer are transparent or translucent, generally colorless, and include natural polymer synthetic resins, polymers and copolymers, and other film-forming media such as: gelatin, gum arabic, and poly (vinyl). Alcohol), hydroxyethylcellulose, cellulose acetate, cellulose acetate butyrate, poly (vinylpyrrolidone), casein, starch, poly (acrylic acid), poly (methyl methacrylic acid), poly (vinyl chloride), poly (methacrylic acid), copoly (Styrene-maleic anhydride), copoly (styrene
-Acrylonitrile), copoly (styrene-butadiene), poly (vinyl acetal) s (eg, poly (vinyl formal) and poly (vinyl butyral)), poly (esters), poly (urethanes), phenoxy resins, poly ( Vinylidene chloride), poly (epoxide) s,
Poly (carbonate) s, poly (vinyl acetate),
There are cellulose esters and poly (amides). The binder may be coated from water or an organic solvent or an emulsion.

In the present invention, the back layer may be an antihalation layer at the same time, and the maximum absorption in a desired wavelength range is preferably 0.3 or more and 2 or less, more preferably 0.5 or more and 2 or less. The absorption in the visible region after the treatment is preferably 0.001 or more and less than 0.5, more preferably 0.001 or more and less than 0.3,
Particularly preferably, the layer has an optical density of 0.001 or more and 0.1 or less. Examples of the antihalation dye used in the back layer are the same as those of the antihalation layer described above.

US Pat. Nos. 4,460,681 and 4,374,921
Backside resistive heating layer (backside resist
ive heating layer) can also be used in the photothermographic image system of the present invention.

A hardener may be used for each layer such as the photosensitive layer, the protective layer and the back layer of the present invention. Examples of hardeners include polyisocyanates described in U.S. Pat.No. 4,281,060 and JP-A-6-208193, epoxy compounds described in U.S. Pat.No.4,791,042, and JP-A-62-89048.
And vinylsulfone compounds described in Nos. 1 and 2 are used.

In the present invention, a surfactant may be used for the purpose of improving coating properties and charging. As the surfactant, any surfactant such as nonionic, anionic, cationic, and fluorine can be used as appropriate. Specifically,
No. 62-170950, U.S. Pat.No.5,380,644, fluorine polymer surfactants described in JP-A-60-244945, JP-A-63
No. 188135, U.S. Patent
No. 3,885,965, etc.
Examples thereof include polyalkylene oxides and anionic surfactants described in JP-A-6-301140.

Examples of the solvent used in the present invention include New Solvent Pocket Book (Ohm Co., 1994), but the present invention is not limited thereto. The solvent used in the present invention has a boiling point of 40 ° C or more and 180 ° C or more.
C. or lower is preferred.

Examples of the solvent of the present invention include hexane, cyclohexane, toluene, methanol, ethanol, isopropanol, acetone, methyl ethyl ketone, ethyl acetate, 1,1,1-trichloroethane, tetrahydrofuran,
Triethylamine, thiophene, trifluoroethanol, perfluoropentane, xylene, n-butanol,
Phenol, methyl isobutyl ketone, cyclohexanone, butyl acetate, diethyl carbonate, chlorobenzene, dibutyl ether, anisole, ethylene glycol diethyl ether, N, N-dimethylformamide, morpholine,
Examples include propane sultone, perfluorotributylamine, and water.

The heat-developable photographic emulsion of the present invention can be coated on various supports. Typical supports include polyester films, primed polyester films, poly (ethylene terephthalate) films, polyethylene naphthalate films, cellulose nitrate films, cellulose ester films, poly (vinyl acetal) films, polycarbonate films and related or resinous Including materials, as well as glass, paper, metal and the like. Flexible substrates, especially coated with partially acetylated or baryta and / or α-olefin polymers, especially polymers of C 2-10 α-olefins such as polyethylene, polypropylene, ethylene-butene copolymers A coated paper support is typically used. Such a support may be transparent or opaque, but is preferably transparent.

The light-sensitive material of the present invention comprises an antistatic or conductive layer, for example, a soluble salt (eg, chloride, nitrate, etc.), a vapor-deposited metal layer, US Pat. No. 2,861,056 and US Pat.
It may have a layer containing an ionic polymer as described in US Pat. No. 206,312 or an insoluble inorganic salt as described in US Pat. No. 3,428,451.

A method for obtaining a color image using the photothermographic material of the present invention is described in JP-A-7-13295, page 10, left column.
There is a method described from the 43rd line to the 11th left column, 40th line. Also, as a stabilizer for color dye images, British Patent No. 1,326,889,
U.S. Patents 3,432,300, 3,698,909, 3,574,627
Nos. 3,573,050, 3,764,337 and 4,042,39
No. 4 illustrates this.

The photothermographic emulsions of the present invention can be coated by various coating operations including dip coating, air knife coating, flow coating or extrusion coating using a hopper of the type described in US Pat. No. 2,681,294. If desired, two or more layers can be coated simultaneously by the methods described in U.S. Pat. No. 2,761,791 and British Patent 837,095.

Additional layers in the photothermographic material of the present invention, such as a dye-receiving layer for receiving a moving dye image, an opaque layer if reflective printing is desired, a protective topcoat layer and photothermographic techniques It may include a known primer layer and the like. The light-sensitive material of the present invention is preferably capable of forming an image with only one light-sensitive material, and it is preferable that a functional layer required for image formation such as an image receiving layer does not become another light-sensitive material.

The light-sensitive material of the present invention may be developed by any method, but is usually developed by raising the temperature of the light-sensitive material exposed imagewise. The preferred development temperature is 80 to
The temperature is 250 ° C, more preferably 100 to 140 ° C.
The development time is preferably from 1 to 180 seconds, more preferably from 10 to 90 seconds.

The light-sensitive material of the present invention may be exposed by any method, but a laser beam is preferred as an exposure light source.
As the laser beam according to the present invention, gas laser, YAG
Lasers, dye lasers, semiconductor lasers and the like are preferred. Further, a semiconductor laser and a second harmonic generation element can be used.

The light-sensitive material of the present invention has a low haze at the time of exposure and tends to cause interference fringes. Examples of this interference fringe prevention technology include a technology for obliquely entering a laser beam into a photosensitive material as disclosed in JP-A-5-113548 and a multi-mode laser disclosed in WO95 / 31754 and the like. Are known, and it is preferable to use these techniques.

To expose the light-sensitive material of the present invention, SPIE vo
l.169 Laser Printing 116-128 (1979), JP-A-4-510
No. 43, WO95 / 31754, etc., it is preferable to expose the laser beams so that they overlap each other so that the scanning lines are not visible.

[0218]

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. Example 1 Preparation of Sample 101 A sample 101 was prepared by coating a single layer photosensitive material on a polyethylene terephthalate film support having a moisture-proof undercoat on both sides containing vinylidene chloride and coated with the following composition. The numbers represent the amount added per m ² . Denkabutyral (5000A) 140mg Dye (D-1) 7mg Thermal radical generator (R-1) 12mg

[0219]

Embedded image

Instead of Dye (D-1), Dye (D-2)
Alternatively, samples to which (D-3) was added in an equimolar amount to (D-1) were designated as Samples 102 and 103, respectively.

[0221]

Embedded image

A sample 104 was prepared in exactly the same manner as sample 101 except that the thermal radical generator (R-1) was not added. These samples were kept at 120 ° C
For 30 seconds and the residual dye absorption was determined. Table 1 shows the results.

[0223]

[Table 1]

From this, it was found that the dye can be efficiently decolorized by heating using a thermal radical generator.

Example 2 (Preparation of dye emulsion) 54 mg of dye (D-4), 120 mg of thermal radical generator (R-2), and 250 mg of dibutyl phthalate were dissolved by heating in 15.4 ml of ethyl acetate. Next, 5% of sodium dodecylbenzenesulfonate
2.5 ml of an aqueous solution and 15.44 g of gelatin were added, and water was further added to adjust the total amount to 60 g. This was emulsified and dispersed with a dissolver for 5 minutes to prepare a dye emulsion a. Dye (D-4) is converted to equimolar amounts of dyes (D-5), (D-6) and (D-7)
The dye emulsions prepared in exactly the same manner as the dye emulsion a except that the above were changed to dye emulsions b, c and d, respectively. In addition, a dye emulsion prepared in exactly the same manner as the dye emulsion a except that the thermal radical generator (R-2) was not added was designated as a dye emulsion e.

[0226]

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(Preparation of Sample 201) The dye emulsion a was coated on a cellulose triacetate film support having a thickness of 127 μm and undercoated so that the coating amount of the dye was 40 mg / m ² . Dye dispersions b to e were applied on a support in the same manner as above to prepare Samples 202 to 205. The samples were heat-developed at 120 ° C. for 30 seconds, and the residual dye absorption was examined. Table 2 shows the results.

[0228]

[Table 2]

From this, it was clarified that the dye can be efficiently decolorized by using the thermal radical generator.

Example 3 (Preparation of silver halide grains) 22 g of phthalated gelatin and 30 mg of potassium bromide were dissolved in 700 ml of water, and the mixture was dissolved at a temperature of 35 ° C.
After adjusting the pH to 5.0, 159 ml of an aqueous solution containing 18.6 g of silver nitrate and 0.9 g of ammonium nitrate and an aqueous solution containing potassium bromide and potassium iodide in a molar ratio of 92: 8 by a control double jet method while maintaining the pAg at 7.7. It was added over a minute. Then, 55.4g of silver nitrate and ammonium nitrate
After adding 476 ml of an aqueous solution containing 2 g and an aqueous solution pAg7.7 containing 10 μmol / l of dipotassium hexachloridate and 1 mol / l of potassium bromide over 30 minutes by a control double jet method, 4- Add 1 g of hydroxy-6-methyl-1,3,3a, 7-tetrazaindene,
Further, the pH was further lowered to perform coagulation sedimentation and desalting treatment. Thereafter, 0.1 g of phenoxyethanol was added, pH 5.9, pAg8.2
Silver iodobromide grains (core iodine content 8 mol%, average 2
Mol%, average size 0.05 μm, projection area variation coefficient 8%, (1
00) cubic particles having an area ratio of 88%).

The silver halide grains thus obtained were heated to 60 ° C., and 85 μmol of sodium thiosulfate and 2,
11 μmol of 3,4,5,6-pentafluorophenyldiphenylphosphine selenide, 15 μmol of a tellurium compound, 3.5 μmol of chloroauric acid, and 270 μmol of thiocyanic acid were added.
After ripening for 0 minutes, the mixture was rapidly cooled to 30 ° C. to obtain a silver halide emulsion.

(Preparation of Organic Acid Silver Emulsion) 7 g of stearic acid,
4 g of arachidic acid, 36 g of behenic acid and 850 ml of distilled water were added with vigorous stirring at 90 ° C. while adding 187 ml of a 1N-NaOH aqueous solution and reacted for 60 minutes. After adding 65 ml of 1N-nitric acid, the temperature was lowered to 50 ° C. Next, 0.62 g of N-bromosuccinimide was added while stirring more vigorously, and 10 minutes later, silver halide grains prepared in advance were added so that the amount of silver halide became 6.2 mmol. Furthermore, add 125 ml of an aqueous solution of 21 g of silver nitrate to 100
The mixture was added over seconds, and the mixture was continuously stirred for 10 minutes, 0.62 g of N-bromosuccinimide was added, and the mixture was further left for 10 minutes. Thereafter, the solid content was separated by suction filtration, and the solid content was washed with water until the conductivity of the filtrate became 30 μS / cm. 150 g of a 0.6% by weight solution of polyvinyl acetate in butyl acetate was added to the solid content thus obtained, and the mixture was stirred. The stirring was stopped, the mixture was allowed to stand, the mixture was separated into an oil layer and an aqueous layer. Next, a 2.5 wt% 2-butanone solution of polyvinyl butyral (Denka Butyral # 3000-K, manufactured by Denki Kagaku Kogyo Co., Ltd.) was added to the oil layer.
g was added and stirred. In addition, pyridinium bromide perbromide
After adding 0.1 mmol and 0.15 mmol of calcium bromide dihydrate together with 0.7 g of methanol, 200 g of 2-butanone and 59 g of polyvinyl butyral (BUTVARTM B-76 manufactured by Monsanto Co.)
Was added and dispersed with a homogenizer to obtain an organic acid silver salt emulsion (acicular particles having an average minor axis of 0.04 μm, an average major axis of 1 μm, and a variation coefficient of 30%).

(Preparation of Coating Solution for Emulsion Layer) Each chemical was added to the above-obtained organic acid silver emulsion in the following amount per mole of silver. Sodium phenylthiosulfonate 10 at 25 ° C
mg, 80 mg dye, 2-mercapto-5-methylbenzimidazole 2 g, 4-chlorobenzophenone-2-carboxylic acid 21.5
g, 2-butanone 580 g, and dimethylformamide 220 g were added with stirring. Then, 5 g of 5-tribromomethylsulfonyl-2-methylthiadiazole, 6 g of 2-tribromomethylsulfonylbenzothiazole, 5 g of 4,6-ditrichloromethyl-2-phenyltriazine, 2 g of a disulfide compound, 1,1-bis ( 155 g of 2-hydroxy-3,5-dimethylphenyl) -3,5,5-trimethylhexane, Megafax F-
176P (fluorinated surfactant manufactured by Dainippon Ink and Chemicals, Inc.) 1.1 g, 2-butanone 590 g, methyl isobutyl ketone 10
g was added with stirring.

The structural formula of the compound used in the above is as follows.

[0235]

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(Emulsion surface protective layer coating solution) 75 g of CAB171-15S (cellulose acetate butyrate manufactured by Eastman Chemical Co., Ltd.), 4-g
5.7 g of methylphthalic acid, 1.5 of tetrachlorophthalic anhydride
g, phthalazine 12.5 g, tetrachlorophthalic acid 5.1 g, 0.3
g Megafax F-176P, Sildex H31 (Dokai Chemical Co., Ltd. spherical silica average size 3 μm) 2 g, sumidur N3500
(Polyisocyanate manufactured by Sumitomo Bayer Urethane Co., Ltd.)
-A solution prepared by dissolving in 3070 g of butanone and 30 g of ethyl acetate was prepared.

(Coating solution for back surface protective layer) Gelatin 10
g, polymethyl methacrylate (average particle size: 7 μm)
6 g, sodium dodecylbenzenesulfonate 0.4
g, X-22-2809 (a silicone compound manufactured by Shin-Etsu Silicone Co., Ltd.) in an amount of 0.9 g was dissolved in 500 g of water to obtain a back surface protective layer coating solution.

(Preparation of Photothermographic Material) The dye emulsions a, b, c, d and e obtained in Example 2 were placed on one side of a 175 μm-thick colored polyethylene terephthalate support having gelatin undercoat on both sides. It was applied so that the absorbance at the absorption maximum was 0.5. An emulsion layer coating solution was coated on the side opposite to the side where the dye of each sample was coated so that the silver content was 2.3 g / m ^2, and the dried thickness was 0% on the side opposite to the emulsion layer. A coating liquid for the back surface protective layer was applied at a flow rate of 0.9 μm. Further, a coating solution for an emulsion surface protective layer was applied on the emulsion surface so as to have a dry thickness of 2 μm.
~ 305 was created. A photothermographic material 306 was prepared in exactly the same manner as the photothermographic material 301 except that the dye emulsion was not coated on the support. The smoothness of the coated light-sensitive material thus obtained (the Beck smoothness was determined by using the Oken-type smoothness measurement described in J. TAPPI Paper Pulp Test Method No. 5) was 900 to 1100 seconds on the emulsion surface, Face 7
The range was 0-100 seconds. Further, the residual amount of the solvent on the coated surface of the emulsion layer in the coated sample was measured by gas chromatography.
Butanone and 40-120 ppm of butyl acetate were detected.

The photothermographic materials 301 to 306 prepared as described above were evaluated as follows.

(Evaluation of Photographic Properties) After exposing the photosensitive material with a 635 nm semiconductor laser photometer, the photosensitive material was processed (developed) at 120 ° C. for 30 seconds, and the obtained image was evaluated with a densitometer. The results of the measurement were evaluated in terms of Dmin (fog) and sensitivity (the reciprocal of the ratio of the exposure amount giving a density higher than Dmin by 1.0). For the sensitivity, set the sensitivity of the photosensitive material 301 to 100.
And

(Evaluation of Sharpness) When a 635 nm semiconductor laser photometer exposed a square having a side of 1 cm, the density was 2.
Assuming that the exposure amount to be 5 is the exposure amount x and the exposure amount to be 0.5 is the exposure amount y, the exposure amount x and the exposure amount y are alternately set so that the long side of the rectangle having the short side of 100 μm and the long side of 1 cm is in contact. The maximum density and the minimum density of the exposed area were measured with a microdensitometer, and the difference between the maximum density and the minimum density divided by 2 was defined as the sharpness. Here, the greater the sharpness, the better the sharpness. Table 3 shows the results.

[0242]

[Table 3]

As is clear from Table 3, the photothermographic materials 301 to 304 of the present invention are superior in sharpness to the comparative photosensitive material 306, and have the same sensitivity as Dmin. At this time, in the comparative photosensitive material 305, since the residual color was extremely large, the image was difficult to see, and the practical problem was large.

The use of the coloring layer which is decolorized by heat according to the present invention is effective for improving the image quality of a dry-processed photographic material, and can provide a decolorizing antihalation layer having little influence on photographic properties. I understood.

Example 4 (Preparation of photothermographic material) (Preparation of silver salt of organic acid emulsion A) 933 g of behenic acid was added to 12 liters of water, and while maintaining at 90 ° C., 48 g of sodium hydroxide,
A solution prepared by dissolving 63 g of sodium carbonate in 1.5 liters of water was added. After stirring for 30 minutes, the temperature is raised to 50 ° C., 1.1 L of a 1% aqueous solution of N-bromosuccinimide is added, and then silver nitrate is added.
2.3 liters of a 17% aqueous solution was added slowly with stirring. Further, set the liquid temperature to 35 ° C, and add potassium bromide while stirring.
1.5 liters of a 2% aqueous solution was added over 2 minutes, followed by stirring for 30 minutes, and 2.4 liters of a 1% aqueous solution of N-bromosuccinimide was added. To this aqueous mixture was added 3300 g of a 1.2% by weight solution of polyvinyl acetate in butyl acetate with stirring, and the mixture was allowed to stand for 10 minutes, separated into two layers, the aqueous layer was removed, and the remaining gel was washed twice with water. The mixture of the gelled silver behenate and silver bromide thus obtained was treated with polyvinyl butyral (Denka Butyral # 3000-K, manufactured by Denki Kagaku Kogyo KK).
Dispersed in 1800 g of a 2.6% 2-butanone solution, and further treated with polyvinyl butyral (Buttvar B-76, manufactured by Monsanto Japan Co., Ltd.)
0 g and 300 g of isopropyl alcohol were dispersed to obtain an organic acid silver salt emulsion (acicular particles having an average minor axis of 0.05 μm, an average major axis of 1.2 μm, and a variation coefficient of 25%).

The compounds used in Example 4 are shown below.

[0247]

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[0248]

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[0249]

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[0250]

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[0251]

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(Preparation of Emulsion Layer Coating Solution A) Each chemical was added to the above-obtained organic acid silver emulsion in the following amount per mol of silver. At 25 ° C., 520 mg of sensitizing dye A, compound (4-1)
1.70 g, 4-chlorobenzophenone-2-carboxylic acid (4-2
21.5 g, 0.90 g of calcium bromide dihydrate, 580 g of 2-butanone, and 220 g of dimethylformamide were added with stirring, and left for 3 hours. Then, 1,1-bis (2-hydroxy-
160 g of 3,5-dimethylphenyl) -3,5,5-trimethylhexane (4-3), 2.1 g of Exemplified Compound B-42 as a contrast agent,
17.7 g of phenyltribromomethylsulfone, dye (4-4
1.11 g, sumidur N3500 (Sumitomo Bayer Urethane Co., Ltd. polyisocyanate) 6.45 g, Megafax F-176P
(Fluorinated surfactant manufactured by Dainippon Ink and Chemicals, Inc.)
0.60 g, 2-butanone 590 g, and methyl isobutyl ketone 10 g were added with stirring.

(Preparation of Coating Solution A for Emulsion Surface Protective Layer) CAB171-15
65 g of S (cellulose acetate butyrate manufactured by Eastman Chemical Co., Ltd.), 5.6 g of phthalazine (4-5), 1.91 g of tetrachlorophthalic acid (4-6), 2.6 g of 4-methylphthalic acid (4-7),
0.67 g of tetrachlorophthalic anhydride (4-8), 0.36 g of Megafax F-176P, 2 g of Sildex H31 (average size of spherical silica 3 μm manufactured by Dokai Chemical Co., Ltd.), and 2-butanone 1050
g and 50 g of dimethylformamide were prepared.

(Preparation of Back Surface Coating Solution) Polyvinyl butyral (Denka Butyral # 4000-, manufactured by Denki Kagaku Kogyo KK)
2) 6g, 0.2g of Sildex H121 (average size 12μm of true spherical silica manufactured by Dokai Chemical), 0.2g of Sildex H51 (average size of 5μm of true spherical silica manufactured by Dokai Chemical), 0.1g of Megafax F- 176P was added to 64 g of 2-propanol with stirring, and dissolved and mixed. Further, a mixed solution of 230 mg of the dye (D-8) and 525 mg of the thermal radical generator (R-1) dissolved in 10 g of methanol and 20 g of acetone,
A coating solution (1) was prepared by adding a solution of 0.8 g of 3-isocyanatomethyl-3,5,5-trimethylhexyl isocyanate dissolved in 6 g of ethyl acetate.

A coating solution prepared in exactly the same manner as the coating solution (1) except that an equimolar amount of the dyes (D-9) to (D-13) was added instead of the dye (D-8) was used. 2)-(6)
And A coating liquid prepared in exactly the same manner as the coating liquids (1) to (6) except that an equimolar amount of the thermal radical generator (R-2) was added instead of the thermal radical generator (R-1) was applied. Liquids (11) to (16) were obtained.

A coating solution prepared in exactly the same manner as the coating solution (1) except that the photoradical generator (R-1) was not used was coated with the coating solution (21), except that the dye (D-1) was not included. Liquid (1)
The coating liquid prepared exactly in the same manner as the coating liquid (22)
And

The back surface coating solutions (1) to (6), (11) to (16), and (21) were coated on a polyethylene terephthalate film having a moisture-proof undercoat containing vinylidene chloride on both sides with an optical density of 0.7 at 780 nm. And apply
The coating liquid (22) was applied so as to have the same coating amount as the coating liquid (1). Samples 401 to 406, 4
11 to 416, 421 and 422.

The emulsion layer coating solution was coated on the support prepared as described above so that the silver content was 1.6 g / m ^2, and the emulsion surface protective layer coating solution was dried on the emulsion surface to a dry thickness of 2.3 μm. It applied so that it might become.

(Evaluation of photographic performance) The film was exposed to xenon flash light having an emission time of 10 ^-4 sec through a step wedge through an interference filter having a peak at 780 nm.
After processing (developing) at 20 ° C. for 20 seconds, the obtained image was evaluated using a densitometer. The result of the measurement was evaluated based on the gradation γ (inclination of a straight line connecting points 0.3 and 3.0 of the characteristic density curve). (Evaluation of Sharpness of Halftone Dots) Using a laser beam of 780 nm, a 50% flat screen of the above sample was output to a coated photosensitive material using a laser beam of 780 nm, and developed under the above-mentioned processing conditions. I checked the halftone dots with a loupe. Evaluation result is 5 (good)
The test was performed using the 1 (evil) 5-point method. Practically, three or more points are required. (Evaluation of Remaining Color of Lowest Density Part) Three samples of the lowest density part of the sample from which the image was obtained were superimposed and evaluated visually. Those that were practically acceptable were evaluated as “OK”, and the other items were evaluated as “impossible”. Table 4 shows the results.

[0260]

[Table 4]

(Results) In the sample in which the dye of the present invention was applied to the back layer, the residual color was small and it was found that the material was a heat-developable photographic material having excellent image quality.

Example 5 The compounds used in Example 5 are shown below.

[0263]

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<< Preparation of Silver Halide Emulsion >> (Emulsion A) 11 g of phthalated gelatin, 30 mg of potassium bromide, 10 mg of sodium benzenethiosulfonate in 700 ml of water
Is dissolved and the pH is adjusted to 5.0 at a temperature of 55 ° C.
An aqueous solution containing 159 ml of an aqueous solution containing 18.6 g and an aqueous solution containing potassium bromide at 1 mol / liter was added by a control double jet method over 6 minutes and 30 seconds while keeping pAg 7.7. Then, 476 ml of an aqueous solution containing 55.5 g of silver nitrate and potassium bromide were added.
An aqueous solution of a halogen salt containing 1 mol / liter was added by a control double jet method over 28 minutes and 30 seconds while maintaining the pAg at 7.7. Thereafter, the pH was lowered to cause coagulation sedimentation and desalting treatment, and 0.17 g of compound (5-1) and 23.7 g of deionized gelatin (calculated as 20 ppm or less) were added.
Adjusted to 5.9 and pAg 8.0. The obtained particles were cubic particles having an average particle size of 0.11 μm, a projection area variation coefficient of 8%, and a (100) plane ratio of 93%.

The silver halide grains thus obtained were heated to 60 ° C., and 76 μmol of sodium benzenethiosulfonate was added per 1 mol of silver.
μmol was added and the mixture was aged for 100 minutes.

Thereafter, the temperature was maintained at 40 ° C.
6.4 × 10 ^-4 mole of sensitizing dye B per mole, 6.4 × 10
^-3 mol of the compound (5-2) was added with stirring, and after 20 minutes, the mixture was rapidly cooled to 30 ° C. to complete the preparation of silver halide emulsion A.

(Preparation of Back Surface Coating Solution) A coating solution containing a dye and a photoradical generator was prepared according to the following formulation. Dyes and radical generators and their amounts shown in Table 5 Sodium dodecylbenzenesulfonate 0.9 g High-boiling solvent-I 3 g Ethyl acetate 45 ml mixed organic solvent phase: Gelatin 12 g 3.5% of compound (5-1) The resulting solution was mixed with an aqueous solution phase in which 1.2 ml of a methanol solution and 87 ml of water were mixed and dissolved, and emulsified and dispersed at 50 ° C. to obtain an emulsion having an average particle diameter of 0.4 μm. 160 ml of water was added to the obtained emulsion, and the mixture was stirred at 50 ° C. and then cooled and solidified to obtain an emulsion containing a dye and a radical generator. The structures of the high boiling point solvents I and D-14 to D-16 are shown below.

[0268]

[Table 5]

[0269]

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<< Preparation of Organic Acid Silver Dispersion >><Organic Acid Silver A> 6.1 g of arachidic acid, 37.6 g of behenic acid, 700 ml of distilled water, 70 ml of tert-butanol, 12N aqueous solution of 1N NaOH
The mixture was stirred at 75 ° C for 1 hour to react, and the temperature was lowered to 65 ° C. Then, 112.5 ml of an aqueous solution of 22 g of silver nitrate was added over 45 seconds, left as it was for 5 minutes, and cooled to 30 ° C.
Thereafter, the solid content was separated by suction filtration, and the solid content was washed with water until the conductivity of the filtrate became 30 μS / cm. The solid content thus obtained was treated as a wet cake without drying, and 5 g of polyvinyl alcohol (trade name: PVA-205) and water were added to a wet cake equivalent to 100 g of dry solid content to make a total amount of 500 g. And then predispersed with a homomixer.

Next, the pre-dispersed stock solution is dispersed in a dispersing machine (trade name: Microfluidizer M-110S-EH, manufactured by Microfluidics International Corporation, using G10Z interaction chamber).
The pressure was adjusted to 1750 kg / cm ² , and the mixture was treated three times to obtain an organic acid silver dispersion A. The organic acid silver particles contained in the organic acid silver dispersion thus obtained have an average minor axis of 0.04 μm and an average major axis of 0.8 μm.
And a needle-like particle having a variation coefficient of 30%. The measurement of the particle size was performed by MasterSizerX manufactured by Malvern Instruments Ltd. In the cooling operation, a coiled heat exchanger was mounted before and after the interaction chamber, and the temperature of the refrigerant was adjusted to a desired dispersion temperature. Thus, organic acid silver A having a silver behenate content of 85 mol% was prepared.

<< Preparation of solid fine particle dispersion of 1,1-bis (2-hydroxy-3,5-dimethylphenyl) -3,5,5-trimethylhexane >> 1,1-bis (2-hydroxy-3, Kuraray (70 g of 5-dimethylphenyl) -3,5,5-trimethylhexane
14 g of MP-203 of MP Polymer Co., Ltd. and 266 ml of water were added thereto, stirred well, and left as a slurry for 3 hours. Thereafter, 960 g of 0.5 mm zirconia silicate beads were prepared, put into a vessel together with the slurry, and mixed with a dispersing machine (1 / 4G sand grinder mill: manufactured by Imex Co., Ltd.).
The mixture was dispersed for a period of time to prepare a solid dispersion of a reducing agent. As for the particle diameter, 80% by weight of the particles were 0.3 μm or more and 1.0 μm or less.

(Preparation of solid fine particle dispersion of tribromomethylphenylsulfone) To 30 g of tribromomethylphenylsulfone were added 0.5 g of hydroxypropylmethylcellulose, 0.5 g of compound 5-3 and 88.5 g of water. The mixture was stirred well and left as a slurry for 3 hours.
Thereafter, a solid fine particle dispersion of the antifoggant was prepared in the same manner as the preparation of the reducing agent solid fine particle dispersion. As for the particle diameter, 80 wt% of the particles were 0.3 μm or more and 1.0 μm or less.

<< Preparation of Solid Fine Particle Dispersion of Ultra-High Contrast Agent >>
2.5 g of POVAL PVA-217 manufactured by Kuraray Co., Ltd. and 87.5 ml of water were added to 10 g of the above compound example B-42, and the mixture was stirred well to form a slurry. A solid particulate dispersion was prepared. As for the particle diameter, 80 wt% of the particles were 0.3 μm or more and 1.0 μm or less.

<< Preparation of Emulsion Layer Coating Solution >> The following binder, material, and silver halide emulsion A were added to 1 mol of silver of the organic acid silver microcrystal dispersion prepared above, and water was added. Thus, an emulsion layer coating solution was obtained.

Binder; Luckstar 3307B 470 g as solid content (manufactured by Dainippon Ink and Chemicals, Ltd .; glass transition temperature of 17 ° C. with SBR latex) 1,1-bis (2-hydroxy-3,5-dimethylphenyl)- 3,5,5-trimethylhexane 110 g as solids Tribromomethylphenyl sulfone 12.2 g as solids Sodium benzenethiosulfonate 0.1 g 6-methylbenzotriazole 1.35 g Polyvinyl alcohol (MP-203 manufactured by Kuraray Co., Ltd.) 46 g 6-iso-butylphthalazine 0.12 mol Dye B 0.62 g Silver halide emulsion A 0.05 mol as Ag amount Super-high contrast agent 8.5 g as solid dispersion B-42 of Exemplified Compound B-42

<< Preparation of Coating Solution for Emulsion Surface Protective Layer >> Solid Content 27.5
wt% polymer latex (methyl methacrylate / styrene / 2-ethylhexyl acrylate / 2-hydroxyethyl methacrylate / acrylic acid = 59/9/26/5 /
Glass transition temperature 55 ° C) with 109 g of H ₂ O 3.7
5 g, and 4.5 g of benzyl alcohol, 0.45 g of compound 5-4, 0.125 g of compound 5-5, and compound 5-
6 1.70 g and polyvinyl alcohol (Kuraray Co., Ltd.)
, PVA-217) Add 0.285 g, add water and add 150
g and the coating liquid.

<< Preparation of Photothermographic Material >> The coating solution for the back surface was coated on a PET support having gelatin undercoat layers on both sides so that the absorption at 780 nm was 1.0. Further, on the opposite side, the above-mentioned emulsion layer coating solution was coated with a silver amount of 1.6 g / m ^2.
It was applied so that Furthermore, the coating amount of the solid content of the polymer latex was set to 2.
It was applied so as to be 0 g / m ² .

<< Evaluation of Photographic Performance >> (Exposure Treatment) The obtained coated sample was exposed to xenon flash light having an emission time of 10 ^-6 seconds through an interference filter having a peak at 780 nm and a step wedge.

(Heat Developing Process) The exposed sample was subjected to a heat developing process at 120 ° C. for 20 seconds in a heat developing machine, and the obtained image was evaluated by a densitometer. The result of the measurement is the gradation γ
(Slope of the straight line connecting points 0.3 and 3.0 of the characteristic density curve) was evaluated. (Evaluation of Sharpness of Halftone Dots) Using a laser beam of 780 nm, a 50% flat screen of the above sample was output to a coated photosensitive material using a laser beam of 780 nm, and developed under the above-mentioned processing conditions. I checked the halftone dots with a loupe. Evaluation result is 5 (good)
The evaluation was performed according to the 1 (bad) 5-point method. Practically, three or more points are required. (Evaluation of Remaining Color of Lowest Density Part) Three samples of the lowest density part of the sample from which the image was obtained were superimposed and evaluated visually. Those which were practically acceptable were evaluated as "OK", and the other objects were evaluated as "impossible". Table 6 shows the results.

[0281]

[Table 6]

(Results) The sample in which the dye of the present invention was applied to the back layer had little residual color, indicating that it was a heat-developable photographic material having excellent image quality.

[0283]

The recording material of the present invention is extremely stable during storage before processing, but has a high image sharpness having a colored layer which can be easily erased without discoloration by heating when necessary. The effect is obtained.

Claims (3)

[Claims] In a recording material having a heat-decolorable coloring layer, the coloring layer is formed by a heat radical generator which generates free radicals by homolytic cleavage of bonds in molecules by heating, and a generated radical. A recording material containing a decolorable dye. 2. A photothermographic material having a photothermographic layer containing at least a reducible silver salt, a photocatalytic substance and a reducing agent, wherein free radicals are generated by homolytic cleavage of bonds in molecules at least by heating. A photothermographic material comprising at least one heat-decolorable colored layer containing a heat radical generator to be generated and a dye decolored by the generated radical. 3. The method according to claim 2, wherein the reducible silver salt is an organic silver salt, the photocatalytic substance is a photosensitive silver halide,
The photothermographic material according to claim 2, further comprising a super-high contrast agent.