JPH09288326A - Heat-developable photosensitive material - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain the infrared sensitive heat-developable photosensitive material good in storage stability, low in fog and high in sensitivity by incorporating photosensitive silver halide grains and a specified cylanine dye. SOLUTION: This photosensitive material contains the photosensitive silver halide grains on at least one side of a support and the cyanine dye represented by the formula [wherein, L is a trivalent bonding group obtained by combining 5 methine groups through conjugated double bonds, such as -CH=CH-CH=CH- CH=, necessary to complete a pentametine cyanine structure; each of R1 and R2 is an alkyl group; Y is a -CH=CH-group or an S or Se atom; each of V1 -V10 is an H atom or a substituent; X is a counter ion necessary for charge balancing; and (1) is 0, 1, or 2]. The photosensitive silver halide grains are spectrally sensitized, preferably, in the region of 750-1,400nm.

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to a photothermographic material.

[0002]

2. Description of the Related Art In recent years, there has been a strong demand in the medical field for reducing the amount of processing waste liquid from the viewpoint of environmental protection and space saving. Thus, a photosensitive heat for medical diagnostics and photographic technology can be efficiently exposed by a laser imagesetter or a laser imager, and can form a sharp black image having high resolution and sharpness. There is a need for technology for developed photographic materials. With these photosensitive photothermographic materials, it is possible to supply the customer with a heat development processing system that eliminates the use of solution processing chemicals and is simpler and does not damage the environment.

On the other hand, semiconductor laser technology, which has made rapid progress in recent years, has enabled downsizing of medical image output devices. Naturally, the technology of infrared-sensitive photothermographic silver halide photographic material that can use a semiconductor laser as a light source was also developed.
No. 387, JP-A-5-341432, JP-A-6-94781, JP-A
No. 6-301141 is disclosed, and as a halation prevention technique, JP-A-7-13295 and US Pat. No. 5,380,635 are disclosed. In the case of a light-sensitive material premised on infrared exposure, the visible absorption of sensitizing dyes and antihalation dyes can be greatly reduced, and a substantially color-free light-sensitive material can be easily produced.

However, a dye that absorbs infrared rays and spectrally sensitizes generally has a high HOMO and thus has a strong reducing ability, and tends to reduce silver ions in the light-sensitive material to deteriorate the fog of the light-sensitive material. In particular, there is a problem that remarkable changes in performance are caused in storage under conditions such as high temperature and high humidity and in storage for a long time. Further, when a dye having a low HOMO is used in order to prevent deterioration of the storage stability, the LUMO becomes relatively low, the spectral sensitization efficiency is lowered, and the sensitivity is lowered. Such problems with sensitivity and storage stability
This is more remarkable not only in wet photographic materials but also in heat-developable photographic materials related to the present invention.

[0005] Naturally, the reducing ability of the dye tends to increase as the amount of the dye increases. However, when the amount of the dye is small, the light incident on the light-sensitive material cannot be sufficiently absorbed, resulting in insufficient sensitivity. In particular, in a heat-developable photosensitive material using a binder having a high lipophilicity, the dye is weakly adsorbed on the silver halide which is a photosensitive element, and the sensitivity becomes insufficient unless a sufficient amount is added.

[0006]

SUMMARY OF THE INVENTION An object of the present invention is to provide an infrared-sensitive photothermographic material having good storage stability, low fog and high sensitivity.

[0007]

This object has been achieved by the following means. (1) A photothermographic material comprising photosensitive silver halide grains on at least one side of a support, wherein the photothermographic material contains a cyanine dye represented by the following general formula (I): And a photothermographic material.

(2) A photothermographic material containing a binder, an organic silver salt, a reducing agent for silver ions, and photosensitive silver halide grains on at least one side of a support. A photothermographic material comprising a cyanine dye represented by formula (I).

(3) The photosensitive silver halide grains are 750 to
The photothermographic material according to (1) or (2), which is spectrally sensitized in a range of 1400 nm.

Formula (I)

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[In the formula, L represents a trivalent linking group in which five methine groups necessary for completing the structure of pentamethinecyanine are linked by a conjugated double bond, and R ₁ and R ₂ are alkyl. Represents a group, Y represents —CH═CH, a sulfur atom or a selenium atom, V ₁ to V ₁₀ each represent a hydrogen atom or a substituent, X represents a counter ion for maintaining charge balance, and i represents Represents 0, 1 or 2. ]

[0012]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below in detail.
In the compound represented by the general formula (I) of the present invention, R
_The alkyl group represented by ₁ or R ₂ is preferably a linear, branched or cyclic alkyl group having 1 to 22 carbon atoms, which may further have a substituent. Examples include a carboxy group, an alkylthio group (preferably having 1 to 4 carbon atoms), an arylthio group (preferably having 6 to 10 carbon atoms), an alkoxy group (preferably having 1 to 4 carbon atoms), an aryloxy group ( Preferably 6 to 10 carbon atoms, an aryl group (preferably 6 to 10 carbon atoms), an alkenyl group (preferably 1 to 4 carbon atoms), a halogen atom (F, Cl, Br, I), a hydroxyl group, Examples thereof include a cyano group and an acyl group (preferably having 1 to 8 carbon atoms). R
₁ or R ₂ may have two or more of these substituents. Particularly preferred substituents among these substituents are a carboxy group and an alkylthio group. In the present invention, either R ₁ or R ₂ is more preferably either, and both are carboxyalkyl groups (preferably having 2 to 2 carbon atoms).
The compound of 8) is preferable.

The substituent represented by V ₁ to V ₁₀ is preferably a group having a Hammett's σ constant of 0.3 or less, and a particularly preferable substituent is an alkyl group having 1 to 6 carbon atoms or 1 carbon atom. To C6 alkoxy group, C6 to C10 aryl group, C1 to C6 alkylthio group, thienyl group, and furyl group. V
₁ and V ₂ , V ₂ and V ₃ , V ₃ and V ₄ may be connected to each other to form an aromatic or aliphatic hydrocarbon ring or a non-aromatic hetero ring. The aromatic hydrocarbon ring is preferably a benzene ring, the aliphatic hydrocarbon ring is preferably a cyclopentene ring or a cyclohexene ring, and the non-aromatic heterocycle is preferably 1,3-.
Examples thereof include a dioxolane ring, a 1,3-oxazoline ring and a 1,4-dioxane ring. The trivalent linking group represented by L is, for example, a group represented by -CH = CH-CH = CH-CH =, and each hydrogen atom may be substituted with a substituent.
Preferred substituents include lower alkyl groups (eg, methyl, ethyl, butyl), phenyl groups, substituted phenyl groups (eg, chlorophenyl group, methylphenyl group, carboxyphenyl group, etc.), aralkyl groups (eg, benzyl group) and the like. And these substituents may be mutually connected to form a ring. The preferred substitution position is the central 3
On one carbon atom, especially on the central carbon atom. As a specific example

[0014]

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And the like.

The counter ion represented by X is represented by the general formula (I)
Is a cation or anion selected such that the total charge of the compound represented by the formula is 0, and Z, Z ₂ , R, R ₂
May be present as a substituent such as Examples of the cation include Na ⁺ , K ⁺ , NH ₄ ⁺ , (n-C ₄ H ₉ ) ₄ N ⁺ ,
N-ethylpyridinium etc. are mentioned. Examples of anions include acid anions (eg chloride, bromide,
Iodide, tetrafluoroborate, hexafluorophosphate, methylsulfate, ethylsulfate, 4-methylbenzenesulfonate, 4-chlorobenzenesulfonate, benzenesulfonate, methanesulfonate, trifluoromethanesulfonate).

Specific examples of the compound represented by formula (I) used in the present invention are shown below, but the scope of the present invention is not limited to these.

[0018]

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[0019]

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[0020]

[Chemical 6]

[0021]

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The compound represented by the general formula (I) used in the present invention can be synthesized by referring to the synthetic methods described in the following documents or the documents cited therein. These documents include, for example, F.M.Harmer, "The Cyanine Soybean and Related Compounds 5 (Interscience Publishers, NY 1964), page 55, Nikolai Tuturkov, Jurgen Fabian, Akim Merhorn, Fritz Dietz, Aria Tazier (Nikol
ai Tyutyulkov, Jurgen Fabian, Achim Ulehlhorn, Fritz
Dietz, Alia Tadjer) "Polymethine Soybean", St. Kliment Ohridski University Press, Soph
ia), pages 23-38, D.M., Starmer (DMSturmer), `` Heterocyclic Compounds-Special Topics in Heterocyclic Compounds-Special
topics in heterocyclic chemistry-) ", Chapter 18, 14
Section, pp. 482-515, John Wiley & Sons, New York, London,
(Published in 1977)., "Rodd's Chemistry of Carbon Compou
nds) '', (2nd.Ed.vol.IV, part B, 1977), No. 15
Chapter, pages 369-422; (2nd.Ed.vol.IV, part B, 1985) Chapter 15, pages 267-296, Elsvier Science Public Company, Inc.
ce Publishing Company Inc.), New York, etc.

Cyanine represented by the general formula (I) of the present invention
Dye is 10 per mol of photosensitive silver halide.^-6~ 1 mo
It is preferred to use in an amount of More preferably,
10 ^-FiveMole-10^-2Is a mole. Further, the cyanide of the present invention
The method of adding the dye is to apply directly from the time of silver halide formation.
Any process up to the previous step is acceptable, but immediately before application is preferred
Yes.

The photosensitive silver halide emulsion for heat development of the present invention is composed of one or more layers on a support.
At least one layer must contain silver halide and preferably contains additional optional materials such as organic silver salts, developers and binders, and toning agents, coating aids and other auxiliaries. The bilayer construction comprises an organic silver salt and a silver halide in the first emulsion layer (usually the layer adjacent to the substrate) and some other components in the second layer or both layers. I won't. However, a two-layer construction comprising a single emulsion layer containing all components and a protective topcoat is also contemplated. The composition of the multicolor photothermographic material may include a combination of these two layers for each color,
It may also contain all components in a single layer as described in US Pat. No. 4,708,928. In the case of a multi-dye, multi-color photothermographic material, each emulsion layer generally employs a functional or non-functional barrier layer between the light-sensitive layers, as described in U.S. Patent No. 4,460,681. By doing so, they are kept distinct from each other.

It is also possible to obtain a desired spectral sensitization spectrum by mixing a plurality of sensitizing dyes in the present invention.

As the sensitizing dye in the present invention, those having a structure other than formula (I) may be used in combination. The dye used in combination is 750 to 14 when adsorbed on silver halide grains.
Those that spectrally sensitize silver halide grains in any wavelength region in the range of 00 nm are preferable. Specifically, the photosensitive silver halide can be spectrally advantageously sensitized by various known dyes, including cyanine, merocyanine, styryl, hemicyanine, oxonol, hemioxonol, and xanthene dyes. Useful cyanine dyes include, for example, thiazoline nuclei, oxazoline nuclei, pyrroline nuclei, pyridine nuclei, oxazole nuclei, thiazole nuclei,
It is a cyanine dye having a basic nucleus such as 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 cyanine and merocyanine dyes, those having an imino group or a carboxyl group are particularly effective. In particular, U.S. Patent Nos. 3,761,279 and 3,7
19,495, 3,877,943, British Patent 1,466,201
No. 1,469,117 No. 1,422,057 No. 3-103
91, Japanese Patent Publication 6-52387, JP-A-5-341432, JP-A-6
-194781, and known dyes described in JP-A-6-301141 may be appropriately selected. The dyes to be used in combination can generally be used in an amount of about 10 .mu.mol to about 1 mol per mol of silver halide. Also, a desired spectral sensitization spectrum can be obtained by mixing a plurality of dyes.

The photothermographic material of the present invention is a so-called single-sided photosensitive material having a photosensitive layer containing at least one silver halide emulsion on one side of a support and a backing layer on the other side. Preferably there is.

The method of forming the photosensitive silver halide of the present invention is well known in the art, for example, Research Disclosure, June 1978, No. 17029, and US Pat.
The method described in 3,700,458 can be used. As a specific method that can be used in the present invention, a method of converting a part of silver of the organic silver salt into a photosensitive silver halide by adding a halogen-containing compound to the prepared organic silver salt, gelatin, Alternatively, a method in which a photosensitive silver halide grain is prepared by adding a silver-supplying compound and a halogen-supplying compound to another polymer solution and mixed 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.
m, preferably 0.01 μm or more and 0.15 μm or less, more preferably 0.02 μm or more and 0.12 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.

Examples of the shape of the photosensitive silver halide grain of the present invention include cubic particles, octahedral particles, tabular particles, spherical particles, rod-shaped particles and potato-shaped particles. In the present invention, cubic particles are particularly preferable. , Tabular grains are preferred. The average aspect ratio when using tabular silver halide grains is preferably 100: 1 to 2: 1, more preferably 50: 1.
~ 3: 1 is good. 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 ratio of the [100] plane, which has high spectral sensitization efficiency when the spectral sensitizing dye is adsorbed, is high. preferable. The ratio is preferably 50% or more, and 65%
More preferably, it is 80% or more. The ratio of the Miller index [100] plane is [111] in the adsorption of the sensitizing dye.
T. Tani; J.
It can be determined by the method described in Imaging Sci., 29, 165 (1985). There is no particular limitation on the halogen composition of the photosensitive silver halide, and silver chloride, silver chlorobromide, silver bromide,
It may be any of silver iodobromide, silver iodochlorobromide and silver iodide, but in the present invention, silver bromide or silver iodobromide can be preferably used. Silver iodobromide is particularly preferred, and the silver iodide content is 0.1 mol% or more and 40 mol% or more.
The following is preferable, and 0.1 mol% or more and 20 mol% or less is more preferable. 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 preferable 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. As the structure, core / shell particles having preferably a 2- to 5-layer structure, more preferably a 2- to 4-layer structure, 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 or iron. 1 of these metal complexes
One kind may be used, or two or more kinds of same metal and different metal complexes may be used in combination. The preferred content is 1n per mol of silver
The preferred range is from 10 to 10 mmol, from 10 to 100 mol.
A μmol range is more preferred. 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. As the compound of cobalt and iron, 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. The phase containing the metal complex in the silver halide may be uniform, may be contained in the core at a high concentration, or may be contained in the shell 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, they 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-organyl tellurocarboxylic acid esters, di (poly) tellurides, tellurides, tellurols, telluroacetals, tellurosulfonates, compounds having a P-Te bond, Te-containing heterocycles, Tellurocarbonyl compounds, inorganic tellurium compounds, colloidal tellurium, and the like can be used. Examples of compounds preferably used in the noble metal sensitization method include chloroauric acid, potassium chloroaurate, potassium aurithiocyanate, gold sulfide, gold selenide, or U.S. Pat.
The compounds described in British Patent 618,061 and the like can be preferably used. As specific compounds of the reduction sensitization method, ascorbic acid, in addition to thiourea dioxide, for example, stannous chloride, aminoiminomethanesulfinic acid,
A hydrazine derivative, a borane compound, a silane compound, a polyamine compound or the like can be used. Also, the pH of the emulsion
It is possible to carry out reduction sensitization by aging while keeping the value of 7 or more or pAg at 8.3 or less. Further, reduction sensitization can be performed by introducing a single addition portion of silver ions 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 are mixed with a high-speed stirrer, ball mill, sand mill, colloid mill, vibration mill, homogenizer, etc. There is a method of mixing, 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, etc. There is no particular limitation as long as it appears.

The organic silver salt that can be used in the present invention is
Relatively stable to light, but in the presence of an exposed photocatalyst (such as a latent image of photosensitive silver halide) and a reducing agent,
A silver salt that forms a silver image when heated to 80 ° C. or higher. The organic silver salt can be any organic substance including a source capable of reducing silver ions. Silver salts of organic acids, especially
Silver salts of long-chain fatty carboxylic acids (having 10 to 30, preferably 15 to 28 carbon atoms) are preferred. Also preferred are organic or inorganic silver salt complexes in which the ligand has a complex stability constant in the range of 4.0 to 10.0. The silver donor can preferably comprise about 5 to 30% by weight of the imaging layer. 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 stearate, silver oleate, silver laurate, silver caproate, silver myristate, silver palmitate, silver maleate, silver fumarate, silver tartrate, silver linoleate, silver butyrate and silver camphorate, and mixtures thereof. including.

Silver salts of compounds containing a mercapto group or a thione group and derivatives thereof can also be used. Preferred examples of these compounds include 3-mercapto-4-
Phenyl-1,2,4-triazole silver salt, 2-mercaptobenzimidazole silver salt, 2-mercapto-5-aminothiadiazole silver salt, 2- (ethylglycolamido) benzothiazole silver salt, S-alkylthio Silver salt of thioglycolic acid such as silver salt of glycolic acid (wherein the alkyl group has 12 to 22 carbon atoms), silver salt of dithiocarboxylic acid such as silver salt of dithioacetic acid, silver salt of thioamide, 5- Carboxyl-1-methyl-2-phenyl-4-thiopyridine silver salt, mercaptotriazine silver salt, 2-mercaptobenzoxazole silver salt, the silver salt described in U.S. Pat.
For example, a silver salt of a 1,2,4-mercaptothiazole derivative such as a silver salt of 3-amino-5-benzylthio-1,2,4-thiazole,
Includes silver salts of thione compounds such as the silver salt of 3- (3-carboxyethyl) -4-methyl-4-thiazoline-2-thione described in US Pat. No. 3,301,678. Furthermore, compounds containing an imino group can 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 benzotriazoles such as silver 5-chlorobenzotriazole, U.S. Pat. Nos. 4,220,709, including silver salts of 1,2,4-triazole or 1-H-tetrazole, silver salts of imidazole and imidazole derivatives, and the like. For example, U.S. Pat.
Various silver acetylide compounds as described in 1,361 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. Since the inversely proportional relationship between the size of silver salt crystal grains and the covering power is well established in the photothermographic material of the present invention as well known in the light-sensitive silver halide photographic material, that is, the photothermographic material It is necessary to reduce the size of the organic silver salt, because if the organic silver salt particles that are the image forming part of the material are large, it means that the covering power is low and the image density is low. In the present invention, the minor axis 0.01
μm or more and 0.20 μm or less, long axis 0.10 μm or more and 5.0 μm or less, short axis 0.01 μm or more and 0.15 μm or less, long axis 0.10
More preferably, it is not less than μm and not more than 4.0 μm. The particle size distribution of the organic silver salt is preferably monodispersed. Monodisperse is the 100% of the value obtained by dividing the standard deviation of the lengths of the short axis and the long axis by the short axis and the long axis, respectively, preferably 100% or less, more preferably 80% or less, and further preferably 50%. It is the following.
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 monodispersity, there is a method of calculating the standard deviation of the volume-weighted average diameter of an organic silver salt, and the percentage divided by the volume-weighted average diameter (coefficient of variation) is preferably 100% or less. ,
It is more preferably at most 80%, further preferably at most 50%. As a measuring method, for example, the particle size (volume-weighted average diameter) obtained by irradiating an organic silver salt dispersed in a liquid with laser light and obtaining an autocorrelation function for the time change of the scattered light fluctuation You can

The organic silver salt of the present invention can be used in a desired amount, but it is preferably 0.1 to 5 g / m ² , more preferably 1 to 3 g.
/ M ² .

The reducing agent for the organic silver salt may be any substance that 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 used in one of the image forming layers.
Should be present as ~ 10% by weight. When a reducing agent is added to a layer other than the emulsion layer in a multilayer structure,
A slightly higher percentage, about 2-15%, tends to be more desirable.

A wide range of reducing agents have been disclosed for photothermographic materials utilizing organic silver salts. For example, phenylamide oxime, 2-thienylamide oxime and p-
Amidooximes such as phenoxyphenylamide oxime; azines such as 4-hydroxy-3,5-dimethoxybenzaldehyde azine; fats such as the combination of 2,2-bis (hydroxymethyl) propionyl-β-phenylhydrazine and ascorbic acid Group carboxylic acid aryl hydrazides and ascorbic acid in combination; polyhydroxybenzenes, hydroxylamines, reductones and / or
Or a combination of hydrazines (eg, hydroquinone and
A combination of bis (ethoxyethyl) hydroxylamine, piperidinohexose reductone or formyl-4-methylphenylhydrazine); hydroxamic acids such as phenylhydroxamic acid, p-hydroxyphenylhydroxamic acid and β-alininehydroxamic acid; Combination of azine and sulfonamide phenol (eg, phenothiazine and 2,6-dichloro-4-benzenesulfonamide phenol); α such as ethyl-α-cyano-2-methylphenylacetate, ethyl-α-cyanophenylacetate -Cyanophenylacetic acid derivative; 2,2-dihydroxy-1,1-binaphthyl, 6,6-dibromo-2,2-dihydroxy
-1,1-binaphthyl and bis-β-naphthol as exemplified by bis (2-hydroxy-1-naphthyl) methane;
Bis-β-naphthol and 1,3-dihydroxybenzene derivatives (for example, 2,4-dihydroxybenzophenone or 2,
5-pyrazolone, such as 3-methyl-1-phenyl-5-pyrazolone;
Diducts such as dimethylaminohexose reductone, anhydrodihydroaminohexose reductone and anhydrodihydropiperidone hexose reductone; 2,6-dichloro-4-benzenesulfonamidephenol and p-benzenesulfone Sulfonamide phenol reducing agents such as amidophenol; 2-phenylindane-1,3-dione etc .; Chroman such as 2,2-dimethyl-7-t-butyl-6-hydroxychroman; 2,6-dimethoxy-3, 1,4-dihydropyridines such as 5-dicarboethoxy-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 and the like); ascorbic acid derivatives (for example, palmitic acid 1-
Ascorbyl, ascorbyl stearate, etc.); and aldehydes and ketones such as benzyl and biacetyl; 3-pyrazolidone and certain indane-1,3-
Dione; chromanol (such as tocopherol). Particularly preferred reducing agents are bisphenol and chromanol.

It may be advantageous to include, in addition to the aforementioned components, additives known as "toning agents" which enhance the image. For example, the toning agent material has a total silver holding component of 0.1 to
It may be present in an amount of 10% by weight. Toning agents are described in U.S. Pat.
As shown in Nos. 80,254, 3,847,612 and 4,123,282, they are well known in the photographic art.

Examples of toning agents include phthalimide and N-hydroxyphthalimide; succinimide, pyrazoline-5-
Quinazolinone, 3-phenyl-2-pyrazolin-5-one, 1-phenylurazole, quinazoline and
Cyclic imides such as 2,4-thiazolidinedione; naphthalimides (eg, N-hydroxy-1,8-naphthalimide); cobalt complexes (eg, cobalt hexamine trifluoroacetate); 3-mercapto-1,2,4 -Triazole, 2,4-dimercaptopyrimidine, 3-mercapto-4,5
N- (aminomethyl) aryldicarboximides; mercaptans exemplified by --diphenyl-1,2,4-triazole and 2,5-dimercapto-1,3,4-thiadiazole;
(For example, (N, N-dimethylaminomethyl) phthalimide and N, N- (dimethylaminomethyl) -naphthalene-2,3-
Dicarboxyimide); 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-benzothiazolinylidene) -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-phthalazinedione A combination of phthalazinone and a phthalic acid derivative (eg, phthalic acid, 4-methylphthalic acid, 4-nitrophthalic acid and tetrachlorophthalic anhydride); phthalazine,
Phthalazine derivatives or metal salts, or derivatives such as 4- (1-naphthyl) phthalazine, 6-chlorophthalazine, 5,7-dimethoxyphthalazine and 2,3-dihydrophthalazine; phthalazine and phthalic acid derivatives (eg, phthalate) acid,
Quinazolinedione, such as 4-methylphthalic acid, 4-nitrophthalic acid and tetrachlorophthalic anhydride;
Benzoxazine or naphthoxazine derivatives; rhodium complexes that function not only as color tone regulators but also in-situ as sources of halide ions for silver halide formation, such as ammonium hexachlororhodate (III), rhodium bromide, rhodium nitrate And potassium hexachlororhodate (III); inorganic peroxides and persulfates, such as ammonium disulfide and hydrogen peroxide; 1,3-benzoxazine-2,4-dione, 8-methyl
-1,3-benzoxazine-2,4-dione and 6-nitro-
Benzoxazine-2,4-diones such as 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-di (o-chlorophenyl) ) -3,6-dimercapto-1H, 4H-2,3a, 5,6a-tetraazapentalene).

In the present invention, a mercapto compound, a disulfide compound, and a thione compound are contained in order to suppress or accelerate development to control development, to improve spectral sensitization efficiency, to improve storage stability before and after development, and the like. be able to. When using a mercapto compound in the present invention, any structure may be used, but 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 ring or a condensed aromatic ring having one or more nitrogen, sulfur, oxygen, selenium or tellurium atoms. Preferably, the heteroaromatic ring is benzimidazole, nafusuimidazole, benzothiazole, naphthothiazole, benzoxazole, naphthoxazole, benzoselenazole, benzotelrazole, imidazole, oxazole, pyrazole, triazole, thiadiazole, tetrazole, triazine, pyrimidine, pyridazine. , Pyrazine, pyridine, purine, quinoline or quinazolinone. The heteroaromatic ring may be, for example, halogen (eg Br and Cl), hydroxy, amino, carboxy, alkyl (eg 1
From one or more carbon atoms, preferably having 1 to 4 carbon atoms) and alkoxy (eg having 1 or more carbon atoms, preferably 1 to 4 carbon atoms) It may have one selected. Examples of the mercapto-substituted heteroaromatic compound include 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-imidazolthiol, 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-hydroxy-2-mercaptopyrimidine, 2-mercaptopyrimidine, 4,6 -Diamino-2-mercaptopyrimidine, 2-mercapto-4-methylpyrimidine hydrochloride, 3-mercapto-5-phenyl-1,2,4-triazole, 2-mercapto-4-phenyloxazole, etc. The 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, and more preferably 0.01 to 1.0 mol per mol of silver.
The amount is 0.3 mol.

The light-sensitive material of the present invention may 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 the like. And mixtures.

In the emulsion layer or the protective layer of the emulsion layer in the present invention, US Pat. Nos. 3,253,921 and 2,274,782 are used.
No. 2,527,583 and 2,956,879 and can be used in photographic elements containing light absorbing materials and filter dyes. Alternatively, dyes can be mordant as described in, for example, US Pat. No. 3,282,699. The amount of the filter dye used is preferably such that the absorbance at the exposure wavelength is 0.1 to 3, and particularly preferably 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, U.S. Patent Nos. 2,992,101 and 2,70.
Polymer beads, including beads of the type described in 1,245, 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 1,000 seconds or more and 10,000 seconds or less, and especially 2
It is preferably 000 seconds or more and 10,000 seconds or less.

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 copolymers, maleic anhydride copolymers, polystyrene and butadiene-styrene copolymers. 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. The effective range can be appropriately determined by those skilled in the art. As a guideline for at least retaining the organic silver salt, the ratio of the binder to the organic silver salt is 15:
The range of 1 to 1: 2, particularly 8: 1 to 1: 1 is preferable.

The photothermographic material of the present invention is a so-called single-sided photosensitive material having a photosensitive layer containing at least one silver halide emulsion on one side of a support and a backing layer on the other side. Preferably there is.

In the present invention, the single-sided light-sensitive material may contain a matting agent for improving the 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. Pat.Nos. 1,939,213, 2,701,245 and 2,322,037.
No. 3,262,782, No. 3,539,344, No. 3,767,448, etc., the organic matting agent described in each specification, No. 1,260,772,
2,192,241, 3,257,206, 3,370,951,
Inorganic matting agents described in the respective specifications such as 3,523,022 and 3,769,020 and the like well known in the art can be used. For example, specifically as an example of an organic compound that can be used as a matting agent, as an example of a water-dispersible vinyl polymer, polymethyl acrylate, polymethyl methacrylate, polyacrylonitrile, acrylonitrile-α-methylstyrene copolymer, polystyrene , Styrene-divinylbenzene copolymer, polyvinyl acetate, polyethylene carbonate, polytetrafluoroethylene, etc. Examples of cellulose derivatives are methyl cellulose, cellulose acetate, cellulose acetate propionate, etc. Examples of starch derivatives are carboxy starch, carboxynitrophenyl Gelatin which has been hardened with a known hardening agent such as starch, urea-formaldehyde-starch reaction product, etc. and hard gelatin such as coacervate hardened into fine capsule hollow particles are preferable. It can be used properly. As examples of the inorganic compound, silicon dioxide, titanium dioxide, magnesium dioxide, aluminum oxide, barium sulfate, calcium carbonate, silver chloride desensitized by a known method, 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
It is preferable to use particles having a particle size of 30 μm. Further, the particle size distribution of the matting agent may be narrow or wide. On the other hand, since the matting agent has a great influence on the haze and surface gloss of the light-sensitive material, the particle size, shape, and particle size distribution can be adjusted to the required state during the preparation of the matting agent or by mixing a plurality of matting agents. preferable.

In the present invention, the Bekk smoothness of the backing layer is preferably 250 seconds or less and 10 seconds or more.
More preferably, it is 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, and also contained in a layer acting as a so-called protective layer. It is preferable.

Suitable binders for the backing layer in the present invention 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, poly (vinyl). Alcohol), hydroxyethyl cellulose, cellulose acetate, cellulose acetate butyrate, poly (vinylpyrrolidone), casein, starch, poly (acrylic acid), poly (methylmethacrylic acid), poly (vinyl chloride), poly (methacrylic acid), copoly (Styrene-maleic anhydride), copoly (styrene-acrylonitrile), copoly (styrene-butadiene), poly (vinyl acetal) s (for example, poly (vinyl formal) and poly (vinyl butyral)), poly (ester) s, Poly Urethanes), phenoxy resins, poly (vinylidene chloride), poly (epoxides),
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 backing layer is 750 to 14
The maximum absorption in the range of 00 nm is preferably 0.3 or more and 2 or less, more preferably 0.5 or more and 2 or less, and the absorption in the visible region is preferably 0.001 or more and less than 0.5, further preferably Is 0.001 or more
It is preferable that the antihalation layer has an optical density of less than 0.3.

When the antihalation dye is used in the present invention, the dye has a desired absorption in the range of 750 to 1400 nm, has a sufficiently small absorption in the visible region, and has a preferable absorbance spectrum shape of the backing layer. Any compound may be used as long as it is possible. For example, JP-A-7-13295, compounds described in U.S. Pat.No. 5,380,635, JP-A-2-68539
From line 1, lower left column on page 13 to line 9, lower left column on page 14, 3-2453
Compounds described in the lower right column of page 14 to the lower right column of page 16 of JP-A No. 9 are exemplified, but the present invention is not limited thereto.

US Pat. Nos. 4,460,681 and 4,374,
The backside resistive heating layer (backside re
A sistive heating layer) can also be used in a photothermographic image system.

Silver halide emulsion or / in the present invention
And the organic silver salts can be further protected against the formation of additional fog and stabilized against loss of sensitivity during storage by antifoggants, stabilizers and stabilizer precursors. Suitable antifoggants, stabilizers and stabilizer precursors that can be used alone or in combination are the thiazonium salts described in U.S. Pat.Nos. 2,131,038 and 2,694,716, U.S. Pat.Nos. 2,886,437 and 2,444,605. Azaindene, U.S. Pat.
728,663 mercury salts, U.S. Pat.No. 3,287,135 urazole, U.S. Pat.No. 3,235,652 sulfocatechol, British Patent 623,448 oxime, nitrone, nitroindazole, U.S. Pat.
No. 405, polyvalent metal salts, U.S. Pat.No. 3,220,839, thyuronium salts, and U.S. Pat.
, Platinum and gold salts described in U.S. Pat. No. 4,597,915 and U.S. Pat. Nos. 4,108,665 and 4,442,20.
Halogen-substituted organic compounds described in US Pat. No. 4,12
Nos. 8,557 and 4,137,079, 4,138,365 and 4,459,350, and the phosphorus compounds described in U.S. Pat. No. 4,411,985.

The photosensitive layer in the present invention contains a polyhydric alcohol as a plasticizer and a lubricant (eg, US Pat. No. 2,
Glycerin and diols of the type described in 960,404), fatty acids or esters described in US Pat. Nos. 2,588,765 and 3,121,060, silicone resins described in British Patent 955,061 and the like.

A hardener may be used in 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 US Pat. No. 4,281,060 and JP-A-6-208193, epoxy compounds described in US Pat. No. 4,791,042, JP-A-62-890
Vinyl sulfone compounds described in No. 48 and the like are used.

In the present invention, a surfactant may be used for the purpose of improving coatability and charging. As the surfactant, any surfactant such as nonionic, anionic, cationic, and fluorine can be used as appropriate. Specifically,
62-170950, U.S. Pat. No. 5,382,504 and other fluorine-containing polymer surfactants, JP-A-60-244945, and 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.

In the present invention, a hydrazine derivative may be used. When the hydrazine derivative is used in the present invention, the compound of the general formula (I) described in Japanese Patent Application No. 6-47961 is used. Specifically, compounds represented by I-1 to I-53 described in the same specification are used.

The following hydrazine derivatives are also preferably used. Compounds represented by (Chemical Formula 1) described in JP-B-6-77138, specifically, compounds described on pages 3 and 4 of the same publication. Compounds represented by the general formula (I) described in JP-B-6-93082, specifically the compounds 1 to 38 described on pages 8 to 18 of the publication. General formula (4) described in JP-A-6-230497, a general formula
(5) and compounds represented by the general formula (6), specifically, Compounds 4-1 to 4-10, 28 described in pages 25 and 26 of the same publication.
Compounds 5-1 to 5-42 on pages 36 to 36, and compounds 6-1 to 6-7 on pages 39 and 40. Compounds represented by general formulas (1) and (2) described in JP-A-6-289520, specifically, compounds 1-1) described on pages 5 to 7 of the same publication
1-17) and 2-1). (Chemical formula 2) described in JP-A-6-313936
And compounds represented by (Chemical Formula 3).
Compounds described on page 19. A compound represented by (Chemical Formula 1) described in JP-A-6-313951, specifically, pages 3 to 5 of the same.
Compounds described on page. General formula (I) described in JP-A-7-5610
And specifically, compounds I-1 to I-38 described on pages 5 to 10 of the publication. A compound represented by the general formula (II) described in JP-A-7-77783, specifically, pages 10 to 27 of the publication
Compounds II-1 to II-102 described on page. A compound represented by the general formula (H) and the general formula (Ha) described in JP-A-7-104426,
Specifically, compounds H-1 to H-4 described on pages 8 to 15 of the publication
Four. A compound characterized by having an anionic group or a nonionic group which forms an intramolecular hydrogen bond with a hydrogen atom of hydrazine in the vicinity of the hydrazine group described in Japanese Patent Application No. 7-191007, particularly a compound represented by the general formula (A): General formula (B), general formula (C), general formula (D), general formula (E), a compound represented by general formula (F), specifically compounds N-1 ~ described in the publication. N-30. A compound represented by the general formula (1) described in Japanese Patent Application No. 7-191007,
Specifically, compounds D-1 to D-55 described in the publication.

When a hydrazine nucleating agent is used in the present invention, a suitable water-miscible organic solvent such as alcohols (methanol, ethanol, propanol, fluorinated alcohol), ketones (acetone, methyl ethyl ketone), dimethylformamide , Dimethyl sulfoxide,
It can be used by dissolving it in methyl cellosolve or the like.
Further, by a well-known emulsification dispersion method, dibutyl phthalate, tricresyl phosphate, oil such as glyceryl triacetate or diethyl phthalate, and an auxiliary solvent such as ethyl acetate or cyclohexanone are dissolved and mechanically emulsified and dispersed. An object can be produced 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.

When a hydrazine-based nucleating agent is used in the present invention, it may be added to any of the silver halide emulsion layer or another hydrophilic colloid layer on the side of the silver halide emulsion layer with respect to the support. However, it is preferable to add to the silver halide emulsion layer or the hydrophilic colloid layer adjacent thereto. The addition amount of the nucleating agent of the present invention is preferably from 1 μm to 10 mmol, more preferably from 10 μm to 5 mmol, and most preferably from 20 μm to 5 mmol, per 1 mol of silver halide.

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 photosensitive silver halide used in the present invention is generally 0.75 to 25 mol% of an organic silver salt,
Preferably it can be used in the range of 2 to 20 mol%.

The photographic emulsion for heat development in the present invention can be coated on various supports. Typical supports include polyester films, subbed 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. Coated with a flexible substrate, especially a partially acetylated or baryta and / or an α-olefin polymer, especially a polymer of an α-olefin having 2 to 10 carbon atoms such as polyethylene, polypropylene, ethylene-butene copolymers. A coated paper support is typically used. The 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, and an ionizable layer as described in US Pat. Nos. 2,861,056 and 3,206,312. Or a layer containing an insoluble inorganic salt or the like as described in US Pat. No. 3,428,451.

As a method for obtaining a color image using the photothermographic material of the present invention, there is a method described in JP-A-7-13295, page 10, left column, line 43 to 11 left column, line 40. Examples of color dye image stabilizers include British Patent No. 1,326,889, U.S. Patent Nos. 3,432,300, 3,698,909, and 3,574,
Nos. 627, 3,573,050, 3,764,337 and 4,042,394.

The photothermographic emulsion 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 US Pat. No. 2,761,791 and British Patent No. 837,095.

In the heat-developable photographic material of the present invention, additional layers such as a dye-receiving layer for receiving a moving dye image, an opacifying 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 necessary for image formation such as an image receiving layer does not serve as another light-sensitive material.

The light-sensitive material of the present invention may be developed by any method, but it is usually developed by heating 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. The laser light according to the present invention includes a 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.

[0069]

Hereinafter, the present invention will be described with reference to Examples.
The present invention is not limited to these. Example 1 << Preparation of silver halide grains >> 22 g of phthalated gelatin and 30 mg of potassium bromide were dissolved in 700 ml of water and dissolved at a temperature of 35.degree.
After adjusting the pH to 5.0, aqueous solution containing 18.6g of silver nitrate 159m
An aqueous solution containing l, potassium bromide and potassium iodide in a molar ratio of 92: 8 was added over 10 minutes by the control double jet method while maintaining pAg 7.7. Then, 476 ml of an aqueous solution containing 55.4 g of silver nitrate and 9 potassium dichloride iridate were added.
While maintaining an aqueous solution pAg7.7 containing μmol / liter and potassium bromide at 1 mol / liter, it was added over 30 minutes by the control double jet method. After that, the pH is lowered to cause coagulation sedimentation, desalting treatment, and 0.1 g of phenoxyethanol is added to adjust the pH to 5.9 and pAg8.2 to prepare silver iodobromide grains (iodine content core 8 mol%, average 2 mol%, average The preparation of cubic particles with a size of 0.05 μm, a projected area variation coefficient of 8% and a (100) plane ratio of 87% was completed.

The silver halide grains thus obtained were heated to 60 ° C. and 85 μmol of sodium thiosulfate was added per mol of silver.
11 μmol of 3,4,5,6-pentafluorophenyldiphenylphosphine selenide, 15 μmol of tellurium compound 1, 2 μmol of chloroauric acid and 200 μmol of thiocyanic acid were added thereto.
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 >> Stearic acid 1.3
g, 0.5 g of arachidic acid, 8.5 g of behenic acid, 300 ml of distilled water
The mixture was mixed at 0 ° C. for 15 minutes, 31.1 ml of a 1N-NaOH aqueous solution was added over 15 minutes while stirring vigorously, and the temperature was lowered to 30 ° C. Next, 7 ml of a 1N-phosphoric acid aqueous solution was added, and 9 mg of N-bromosuccinimide was added while stirring more vigorously.
5 mmol was added. Further, 25 ml of a 1N aqueous solution of silver nitrate was added over 2 minutes, and stirring was continued for 90 minutes. afterwards,
The solid content is separated by suction filtration, and the solid content is 30%.
It was washed with water until it became μS · cm. To the solid thus obtained, 37 g of a 1.2 wt% butyl acetate solution of polyvinyl acetate was added and stirred, and the stirring was stopped and the mixture was allowed to stand to separate the oil layer and the water layer, and the salt and the aqueous layer were removed to obtain an oil layer. Next, 20 g of a 2.5 wt% 2-butanone solution of polyvinyl butyral (Denka Butyral # 3000-K, manufactured by Denki Kagaku Kogyo KK) was added to the oil layer and stirred. Furthermore, after adding 0.1 mmol of pyridinium perbromide bromide and 0.1 mmol of calcium bromide dihydrate together with 0.7 g of methanol, 40 g of 2-butanone and 7.8 g of polyvinyl butyral (PVB B-76 manufactured by Monsanto Co.) Was added and dispersed with a homogenizer to produce an organic acid silver salt emulsion (average minor axis 0.04 μm
m 2, an average major axis of 1 μm, and a coefficient of variation of 29% were obtained.

<< Preparation of Emulsion Layer Coating Solution >> Emulsion layer coating solution A was prepared by adding the respective chemicals to the organic acid silver emulsion obtained above in the following amounts per mol of silver. At 25 ° C, while stirring 10 mg of sodium phenylthiosulfonate, 70 mg of dye 3, 2-mercapto-5-methylbenzimidazole 2 g, 4-chlorobenzophenone-2-carboxylic acid 21.5 g, 2-butanone 580 g, and dimethylformamide 220 g. The mixture was added and left for 3 hours. Then, 5-tribromomethylsulfonyl-2-methylthiadiazole 8g, 2-tribromomethylsulfonylbenzothiazole 6g, 4,6-ditrichloromethyl-2-phenyltriazine 5g, disulfide compound 1 2g, 1,1-bis (2-Hydroxy-3,5-dimethylphenyl) -3,5,5-trimethylhexane 155 g, tetrachlorophthalic acid 5 g, Megafax F-176P (Dainippon Ink and Chemicals, Inc. fluorinated surfactant) 1.1 g, 2-butanone 590 g and methyl isobutyl ketone 10 g were added with stirring. Dye 7,10,
Emulsion coating solutions B to E were prepared by using Comparative Dyes 1 and 2 instead of Dye 3 in equimolar amounts.

<< Emulsion side protective layer coating solution >> CAB171-15S (Eastman Chemical Co., Ltd. cellulose acetate butyrate) 75 g, 4-
Methylphthalic acid 5.7g, tetrachlorophthalic anhydride 1.5
g, phthalazine 12 g, 0.3 g of Megafax F-176P, Sildex H31 (Dokai Chemical Co., Ltd. true spherical silica average size 3
μm) 2 g, sumidur N3500 (Sumitomo Bayer Urethane Polyisocyanate 6 g) 2-butanone 3070 g and ethyl acetate 30
g was prepared.

<< Back Surface Coating Liquid >> Synthesis of Calcium Compound 1 was synthesized as follows. 0.08 mol of 3,5-di-tert-bu
0.1 liter of ethanol solution containing tylcatechol.
019 Aqueous solution containing 167 ml and 25 mol of calcium chloride
% 125% ammonia water and blown with air for 3 hours at room temperature to give bis [2- (3,5-di-tert-butyl-o-benzoquinone
monoimine) -4,6-di-tert-butyl phenolato] Calcium (I
Crystals of I) (calcium compound 1) were deposited. Polyvinyl butyral (Denka Butyral # 4000-2 manufactured by Denki Kagaku Kogyo Co., Ltd.) 12g, CAB381-20 (Cellulose acetate butyrate manufactured by Eastman Chemical Co., Ltd.) 12g, 120 mg of dye 1,300
mg of calcium compound 1, 350 mg of dye 2, 5 mg of dye 3, Sildex H121 (average particle size of spherical silica made by Dokai Chemical Co., Ltd. 12 μm) 0.4 g, Sildex H51 (average particle size of spherical silica made by Dokai Chemical, 5 μm) ) 0.4 g, 0.1 g Megafax F-176P, 2 g sumidur N3500 were added to 500 g 2-butanone, 500 g 2-propanol with stirring, dissolved and mixed.

Emulsion layer coating solutions A to E prepared as described above
Was coated on a 175 μm polyethylene terephthalate support tinted with a blue dye so that the silver content would be 2.3 g / m ^2, and then the back side coating solution was applied on the side opposite to the emulsion layer to give an optical density of 0.7 at 810 nm. It was applied so that Further, an emulsion surface protective layer coating solution was applied onto the emulsion surface so that the dry thickness was 2 μm. The smoothness of the light-sensitive materials A to E thus obtained (J.TAP
The Beck's smoothness was measured using the Oken type smoothness measurement described in PI Paper Pulp Test Method No. 5), and the emulsion side was 1000 seconds and the back side was 80 seconds.

[0076]

Embedded image

(Evaluation of Photographic Performance) After exposing the photographic material with a laser sensitometer equipped with an 810 nm diode, the photographic material was processed (developed) at 120 ° C. for 15 seconds, and the obtained image was evaluated by a densitometer. It was The measurement result is Dmin, sensitivity (Dmi
(the reciprocal of the ratio of the exposure amount giving a density higher by 1.0 than n). The sensitivity was shown as a relative value with the value of Sample 1 being 100.

(Evaluation of storability over time) Each sample processed in the same manner as the transportability evaluation was left for 1 day under the condition of 25 ° C.-50% RH, and 10 pieces of each photographic material were placed in a bag made of moisture-proof material. Then, put it in a 35.1 cm × 26.9 cm × 3.0 cm cosmetic box and
The sample was aged at 5 ° C for 5 days (forced aging). The same treatment as that used for evaluation of photographic properties was performed on this sample and a sample prepared in the same manner as in forced aging except that the storage temperature was 4 ° C. for comparison, and the density of the fog portion was measured. The natural aging property was evaluated as a fog increase rate. (Fog increase rate) = [[(fog of sample after forced aging)-(fog of comparative sample)] / [(highest density of comparative sample)-(concentration of support)] x 100 Good property.

Table 1 shows the results of the above evaluations performed on each of the photosensitive materials. Regarding the sensitivity, the sensitivity of the photographic material 1 was set to 100.

(Evaluation of storability of light-irradiated image) The photosensitive material exposed and developed in the same manner as in the evaluation of photographic property was attached to the inside of a glass window exposed to direct sunlight and left standing for 1 month, and the state of the image was visually evaluated according to the following criteria. did. ◎ ... There is almost no change. ○: There is a slight change in color tone, but it does not bother me. Δ: Practically acceptable although there is discoloration in the image area. ×: Dmin is discolored and the density cannot be increased.

(Evaluation of storability of dark heat image) The photosensitive material exposed and developed in the same manner as in the photographic evaluation was left to stand at 40 ° C. for 1 month under a light-shielded condition, and the state of the image was visually evaluated according to the following criteria. ◎ ... There is almost no change. ○: There is a slight change in color tone, but it does not bother me. Δ: Practically acceptable although there is discoloration in the image area. ×: Dmin is discolored and the density cannot be increased.

Table 1 shows the results. It can be seen that within the range of the present invention, the feeling is high, the Dmin is low, and the storage stability over time and the image storage stability are excellent.

[0083]

[Table 1]

Example 2 << Preparation of Organic Acid Silver Emulsion >> Behenic acid 840 g, Stearic acid 95
While adding g to 12 liters of water and maintaining the temperature at 90 ° C, a solution prepared by dissolving 48 g of sodium hydroxide and 63 g of sodium carbonate in 1.5 liters of water was added. After stirring for 30 minutes, the temperature was raised to 50 ° C., 1.1 L of a 1% aqueous solution of N-bromosuccinimide was added, and then 2.3 L of a 17% aqueous solution of silver nitrate was gradually added with stirring. Further, the liquid temperature was set to 35 ° C., 1.5 liters of a 2% aqueous solution of potassium bromide was added with stirring over 2 minutes, and then the mixture was stirred for 30 minutes, and 2.4 liters of a 1% aqueous solution of N-bromosuccinimide was added. 3300 g of 1.2% by weight polyvinyl acetate in butyl acetate while stirring in this aqueous mixture
Was added and left standing for 10 minutes to separate into two layers, the aqueous layer was removed, and the remaining gel was washed twice with water. The gel-like mixture of behenic acid / silver stearate and silver bromide thus obtained was dispersed in 1800 g of a 2.6% isopropyl alcohol solution of polyvinyl butyral (Denka butyral # 3000-K manufactured by Denki Kagaku Kogyo Co., Ltd.), and further dispersed in polyvinyl. Butyral (Denka Butyral # 4000-, manufactured by Denki Kagaku Kogyo Co., Ltd.)
2) 600 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 coefficient of variation of 25%).

<< Preparation of Emulsion Layer Coating Solution >> Each of the chemicals was added to the above-obtained organic acid silver emulsion in the following amount per mol of silver. Sodium phenylthiosulfonate 10 at 25 ° C
mg, 70 mg of dye 7, 2-mercapto-5-methylbenzimidazole 2 g, 4-chlorobenzophenone-2-carboxylic acid 2
1.5 g, 2-butanone (580 g) and dimethylformamide (220 g) were added with stirring and the mixture was allowed to stand for 3 hours. Then, 8 g of 5-tribromomethylsulfonyl-2-methylthiadiazole,
6 g of 2-tribromomethylsulfonylbenzothiazole,
5.1 g of 4,6-ditrichloromethyl-2-phenyltriazine,
2 g of disulfide compound 1, 1,1-bis (2-hydroxy-3,
5-Dimethylphenyl) -3,5,5-trimethylhexane 160
g, tetrachlorophthalic acid 5 g, 2.3 g hydrazine derivative a
, Megafax F-176P (Dainippon Ink and Chemicals Co., Ltd. fluorinated surfactant) 1.1 g, 2-butanone 590 g,
10 g of methyl isobutyl ketone were added with stirring.
The emulsion layer coating solution thus obtained was designated as X, and dyes 10 and comparative dye 1 were used in place of Dye 7 in equimolar amounts and designated as Y and Z.

<< Emulsion Surface Protective Layer Coating Solution >> 75 g of CAB171-15S (cellulose acetate butyrate manufactured by Eastman Chemical Co., Ltd.)
Methylphthalic acid 5.7g, tetrachlorophthalic anhydride 1.5
g, phthalazine 13 g, 0.3 g of Megafax F-176P, Sildex H31 (average size of spherical silica 3 manufactured by Dokai Chemical Co., Ltd.)
μm) 2 g, 7 g of sumidur N3500 (polyisocyanate manufactured by Sumitomo Bayer Urethane Co.) and 3070 g of 2-butanone and ethyl acetate
A 30 g solution was prepared.

<< Preparation of Support Having Back Side >> 100 μm in thickness on both sides of a moisture-proof undercoat containing vinylidene chloride
A back layer similar to that of Example 1 was coated on the polyethylene terephthalate film of.

After coating the emulsion layer coating liquid on the support prepared as described above so that the silver content was 2 g / m ² , the emulsion surface protective layer coating liquids X to Z were dried to a thickness of 2 μm. And coated so that Sensitive Materials X to Z were obtained.

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Embedded image

(Evaluation of Photographic Performance of High-Density Sensitive Material) After exposing the photographic material with a laser sensitometer equipped with a 820 nm diode,
The photographic material was processed (developed) at 115 ° C. for 25 seconds, and the obtained image was evaluated by a densitometer. The measurement result is Dmin,
The sensitivity was evaluated (the reciprocal of the ratio of the exposure dose that gives a density 3.0 higher than Dmin). The sensitivity is shown as a relative value with sample X being 100. Also, the slope of the straight line connecting the points of density 0.3 and 3.0 in the characteristic curve is shown as the gradation γ.

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[Table 2]

As shown in Table 2, within the range of the present invention, high feeling and low feeling are obtained.
It can be seen that Dmin and the contrast are high.

[0093]

The heat-developable photosensitive material of the present invention has low fog, high sensitivity, and high contrast, and is excellent in preservability before and after processing.

Claims (3)

[Claims] 1. A photothermographic material comprising photosensitive silver halide grains on at least one side of a support, wherein the photothermographic material contains a cyanine dye represented by the following general formula (I). A photothermographic material characterized by: General formula (I) [Wherein L represents a trivalent linking group in which five methine groups necessary for completing the structure of pentamethinecyanine are linked by a conjugated double bond, and R ₁ and R ₂ represent an alkyl group. , Y represents -CH = CH, a sulfur atom or a selenium atom,
V ₁ to V ₁₀ each represent a hydrogen atom or a substituent, X represents a counter ion for maintaining charge balance, and i represents 0, 1 or 2. ] 2. A photothermographic material comprising a support, an organic silver salt, a reducing agent for silver ions, and photosensitive silver halide grains on at least one side of the support, wherein the photothermographic material comprises: 1. A photothermographic material comprising the cyanine dye represented by formula (I) described in 1. 3. The photosensitive silver halide grain comprises 750 to 1
3. The photothermographic material according to claim 1, which is spectrally sensitized in the range of 400 nm.