JP2000019681A - Heat-developable photosensitive material - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain the heat-developable photosensitive material superior in image storage stability after heat development for a long period and in silver color tone by incorporating >=2 kinds of specified compounds in the photosensitive material. SOLUTION: The heat-developable photosensitive material formed on a support contains an organic silver salt, photosensitive silver halide grains, a reducing agent, at least one kind of the compound represented by formula I and at least one kind of the compound represented by formula II, and in formulae I and II, each of Y1 and Y2 is an N atom or a CR2 group; R2 is an H atom or an optionally substituted alkyl group or the like; R1 is one or more sulfo groups or their salts or a carboxy group or its salt or an optionally substituted aminoalkyl group or the like; M1 is an H or alkali metal atom or the like; each of Y3 and Y4 is an N atom or a CR4 group; R4 is an H atom or an optionally substituted alkyl group or the like; R3 is a sulfo or carboxy group or one of their salts or an acylamino group or the like; and M2 is an H or alkali metal atom.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a photothermographic material having improved image storability after development.

[0002]

2. Description of the Related Art Conventionally, in a silver halide photographic material for printing plate making or medical use, there is a problem in terms of workability in the preparation of a solution due to wet processing, and in recent years, from the viewpoint of environmental conservation and space saving. Also, it is strongly desired to reduce the amount of processing waste liquid.

[0003] Therefore, there is a demand for a photographic technique capable of efficiently exposing with a laser image setter or a laser imager and forming a high-resolution and clear black image.

[0004] For example, US Pat. No. 3,152,904 and US Pat.
And D. Morgan's "Dry Silver"
Photographic Materials "and D.C. Morgan and B.M. "Therm by Shelly
all Processed Silver Sys
tems ". (Imaging Processes
and Materials, Neblette, 8th
Edition, Sturge, V. Walworth, A .; She
pp. ed., page 2, 1969).

[0005] Such a photothermographic material is usually 80
In order to form an image by heat development at a temperature of from 140 to 140 ° C., the support generally contains an organic silver salt, photosensitive silver halide grains and a reducing agent.

The photosensitive material is characterized in that an image is generally formed by heat development at 80 to 140 ° C., and no fixing is performed. Therefore, the silver halide and organic silver remaining after the heat development are not removed and remain in the photosensitive material as they are.

[0007] The remaining silver halide or organic silver salt may cause an increase in fog density in unexposed areas, coloring, or discoloration of the image silver to a warm black tone when the image is stored. It is a fact that they have serious obstacles such as
The present invention has been made in view of the above circumstances.

[0008]

SUMMARY OF THE INVENTION Accordingly, an object of the present invention is to provide a photothermographic material which is excellent in long-term preservability of images after heat development and silver tone.

[0009]

The object of the present invention has been attained by the following constitutions.

(1) In a photothermographic material having an organic silver salt, photosensitive silver halide particles and a reducing agent on a support, at least one compound represented by the following general formula (1) is contained in the photosensitive material. A photothermographic material comprising a seed and at least one compound represented by the following general formula (2).

[0011]

Embedded image

(Wherein Y ¹ and Y ² are each a nitrogen atom or CR
_And R ₂ represents a hydrogen atom, a substituted or unsubstituted alkyl group, or a substituted or unsubstituted aryl group. R ₁ represents a (one or more) sulfo group or a salt thereof, a carboxy group or a salt thereof, a substituted or unsubstituted aminoalkyl group, a hydroxy group or an aryl group substituted with a boron residue. M ₁ represents a hydrogen atom, an alkali metal atom, or an ammonium group. )

[0013]

Embedded image

(Wherein Y ³ and Y ⁴ are each a nitrogen atom or CR
_And R ₄ represents a hydrogen atom, a substituted or unsubstituted alkyl group, or a substituted or unsubstituted aryl group. R ₃ is a sulfo group or a salt thereof, a carboxy group or a salt thereof, an acylamino group, a hydroxy group or a carbon atom substituted with a boron residue.
-20 represents an alkyl group. M ₂ represents a hydrogen atom, an alkali metal atom, or an ammonium group. Hereinafter, the present invention will be described in detail.

In the photothermographic material containing the organic silver salt, the photosensitive silver halide grains and the reducing agent of the present invention, at least one of each of the compounds represented by the above general formulas (1) and (2) is contained. The seed is contained.

In the compound represented by the formula (1), Y ¹ and Y ² each represent a nitrogen atom or CR ₂ , and R ₂ represents a hydrogen atom, a substituted or unsubstituted alkyl group, a substituted or unsubstituted alkyl group, Represents an unsubstituted aryl group. R ₁ represents an aryl group substituted with the following group. One or more sulfo groups or salts thereof, carboxy groups or salts thereof, substituted or unsubstituted aminoalkyl groups, hydroxy groups or boron residues.

M ₁ represents a hydrogen atom, an alkali metal atom or an ammonium group. Here, examples of the substituted or unsubstituted alkyl group and the substituted or unsubstituted aryl group include a lower alkyl group having 1 to 4 carbon atoms, a phenyl group and a naphthyl group.

A sulfo group or a salt thereof, a carboxy group or a salt thereof (here, for example, sodium and potassium) substituted with R ₁ , a substituted or unsubstituted aminoalkyl group (eg, dimethylaminoethyl, dimethylaminopropyl group) Acetylaminomethyl, acetylaminoethyl, etc.) represents a hydroxy group or an aryl group (preferably a phenyl group) substituted with a boron residue. M ₁ represents a hydrogen atom, an alkali metal atom (eg, sodium or potassium), or an ammonium group.

When two or more of these substituents are substituted on the aryl group, they may be the same or different.

In the compound represented by formula (2), Y ³ and Y ⁴ in the formula have the same meanings as Y ¹ and Y ² in formula (1). R ₃ in the formula represents an alkyl group having 1 to 20 carbon atoms substituted by the following groups. A sulfo group or a salt thereof, a carboxy group or a salt thereof (here, for example, sodium or potassium), an acylamino group, a hydroxy group or a boron residue. M ₂ represents a hydrogen atom, an alkali metal atom (eg, sodium or potassium), or an ammonium group.

In the general formula (1), R ₁ is preferably a phenyl group substituted by one or more sulfo, carboxy or hydroxy groups.

In the formula (2), R ₃ is preferably a methyl group, an ethyl group or a propyl group substituted by a sulfo group, a carboxy group or a hydroxy group. Particularly preferred as R ₂ and R ₄ are a hydrogen atom.

Hereinafter, specific examples of the compounds represented by formulas (1) and (2) of the present invention will be shown, but the present invention is not limited thereto.

(Specific examples of the compound represented by the general formula (1))

[0025]

Embedded image

[0026]

Embedded image

[0027]

Embedded image

[0028]

Embedded image

[0029]

Embedded image

[0030]

Embedded image

[0031]

Embedded image

(Specific examples of the compound represented by the general formula (2))

[0033]

Embedded image

The effects of the present invention cannot be obtained even when each of the above compounds of the present invention is used alone.
The effects of the present invention can be obtained only when one or more compounds of (2) are used in combination. The compound represented by formula (1) or (2) may be added to the emulsion layer in which the photosensitive silver halide grains of the present invention are present or to the hydrophilic colloid layer on the side where the emulsion layer is present. And more preferably an emulsion layer in which photosensitive silver halide grains are present.

The amount of the compound represented by the general formula (1) may be from ^{2 to} 150 mg, more preferably from 5 to 110 mg, per m ² of the photographic material. The compound represented by the general formula (2) is used in an amount of 0.5 to 80 mg / m ² of the photosensitive material.
And more preferably 2 to 60 mg. The addition method may be mixed and added simultaneously, or may be added separately. The compound may be added at any time from the formation of silver halide grains to the coating step, but preferably from the end of chemical ripening to before the coating step.

The particle size of the photosensitive silver halide particles used in the photothermographic material of the present invention is preferably small for the purpose of suppressing white turbidity during image formation. 2 μm or less, more preferably 0.01 μm
０．１0.17 μm, especially 0.02 μm to 0.14 μm. Here, the grain size refers to 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 silver halide grains are preferably monodispersed. Here, the monodispersion means that the degree of monodispersion determined by the following equation is 40 or less. The particle size is more preferably 30 or less, and particularly preferably 0.1 or more and 20 or less.

Monodispersity = (standard deviation of particle size) / (average value of particle size) × 100 The shape of silver halide grains is cubic, octahedral, tabular, spherical, rod-like, potato-like. In the present invention, cubic grains and tabular grains are particularly preferred. When tabular silver halide grains are used, the average aspect ratio is preferably 2 or more and 10 or more.
It is preferably 0 or less, more preferably 3 or more and 50 or less. These are disclosed in U.S. Pat. Nos. 5,264,337 and 5,314,79.
No. 8, No. 5,320,958, etc., and target tabular grains can be easily obtained.

Further, grains having rounded corners of silver halide grains can be preferably used. The outer surface of the silver halide grains is not particularly limited, but has a Miller index [1
[00] plane is preferably high, and this ratio is preferably at least 50%, more preferably at least 70%, particularly preferably at least 80%. The ratio of the Miller index [100] plane is determined by the T.M. Tani, J .; Imagin
g Sci. , 29, 165 (1985).

The halogen composition is not particularly limited, and may be any of silver chloride, silver chlorobromide, silver chloroiodobromide, silver bromide, silver iodobromide 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%, 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 a preferred example is silver iodide inside the grains. Silver iodobromide grains having a high content can be used. Further, silver halide grains having a core / shell structure can be preferably used.

The photographic emulsion used in the present invention is described in US Pat. Gl
Chimie et Physique by Afkids
e Photographique (Paul Mon
tel, 1967); F. By Duffin
Photographic Emulsion Chem
istry (published by The Focal Press, 19
66); L. M by Zelikman et al
aking andCoating Photogra
phi Emulsion (The Focal P
Ress, published in 1964) and the like. That is, any of an acidic method, a neutral method, an ammonia method and the like may be used, and a method of reacting a soluble silver salt and a soluble halide may be any one of a one-side mixing method, a simultaneous mixing method, a combination thereof and the like. Good. The silver halide may be added to the image forming layer by any method, in which case the silver halide is arranged close to the reducible silver source. Further, the silver halide may be prepared by converting a part or all of the silver in the organic acid silver by the reaction of the organic acid silver and the halogen ion into silver halide, or may be prepared by preparing silver halide in advance. In advance, this may be added to a solution for preparing an organic silver salt, or a combination of these methods is possible, but the latter is preferred. Generally, the silver halide is preferably contained in an amount of 0.75 to 30% by weight based on the organic silver salt.

The silver halide grains used in the present invention preferably contain a complex of a metal selected from the group consisting of Fe, Co, Ru, Rh, Re, Os, and Ir. Two or more complexes may be used in combination. The preferred content is in the range of 1.times.10.sup.- ⁹ mol to 1.times.10.sup.- ² mol per mol of silver, more preferably 1.times.10.sup.- ⁸ mol to 1.times.10.sup.- ⁴ .

In the present invention, the transition metal complex is preferably a six-coordinate complex or a complex ion represented by the following general formula.

In the formula [ML ₆ ] ^m , M is a transition metal selected from elements of Groups 6 to 10 of the periodic table, L is a bridging ligand, and m is 0, -1, -2, -3.
Or -4. Specific examples of the ligand represented by L include halides (fluoride, chloride, bromide and iodide), cyanide, cyanate, thiocyanate, selenocyanate, tellurocyanate, azide and aquo. Ligand, nitrosyl, thionitrosyl and the like, preferably aquo, nitrosyl and thionitrosyl. If an aquo ligand is present, it preferably occupies one or two of the ligands. L may be the same or different. R is rhodium (Rh), ruthenium (Ru), rhenium (Re), osmium (O
Preferred specific examples of s) and iridium (Ir) are shown below.

[0046] 1: [RhCl _6] ^3- 2: [RhCl ₅ (H ₂ O)] ^2- 3: [Rh (NO) ₂ Cl _4] ^- 4: _{[Rh (NO) (H 2 O} ) Cl 4 ] ^- 5: [Rh (NS) Cl _5] ^2- 6: [RuCl _6] ^3- 7: [RuBr _6] ^3- 8: [Ru (NO) Cl _5] ^2- 9: [Ru (NO) ( H ₂ O) Cl _4] ^- 10: [Ru (NS) Cl _5] ^2- 11: [RuBr ₄ (H ₂ O)] ^2- 12: [Ru (NO) CN _5] ^2- 13: [ReCl ₆ ^3- 14: [Re (NO) Cl _5] ^2- 15: [Re (NO) CN _5] ^2- 16: [Re (NO) ClCN _4] ^2- 17: [Re (NO) Cl _5] ^- 18: _{[Re (NS) Cl 4 (SeCN} ) ] ^2- 19: [OsCl _6] ^3- 20: [Os (NO) Cl _5] ^2- 21: _{[Os (NS) Cl 4 (TeCN} ) ] ^2- 22: [Os (NS) Cl (SCN) _4] ^2- 23: [IrCl ₅ ^2- 24: is preferably used hexacyano metal complex for [Ir (NO) Cl _5] ^2- chromium, cobalt, iron compound . Specific examples are shown below.

25: [Cr (CN) ₆ ] ^3- 26: [Cr (CN) ₆ ] ^4-27 : [Fe (CN) ₆ ] ^4-28 : [Fe (CN) ₆ ] ^3-29 : [ Co (CN) ₆ ] ^3- A compound providing an ion or a complex ion of these metals is preferably added at the time of forming silver halide grains and incorporated into silver halide grains. That is, it may be added at any stage before and after nucleation, growth, physical ripening, and chemical sensitization.
It is preferably added at the stage of physical ripening, more preferably at the stage of nucleation and growth, and most preferably at the stage of nucleation.

In the addition, it may be added in several divided portions, may be added uniformly in the silver halide grains, or may be added to silver halide grains.
-306236, 3-167545, 4-76
No. 534, No. 6-110146, No. 5-273683
As described in Japanese Patent Application Laid-Open No. H10-284, etc., the particles can be contained in the particles with a distribution. It is preferable to have a distribution inside the particles.

These metal compounds can be added by dissolving them in water or a suitable organic solvent (eg, alcohols, ethers, glycols, ketones, esters, amides). Or an aqueous solution in which a metal compound and NaCl and KCl are dissolved together is added to a water-soluble silver salt solution or a water-soluble halide solution during grain formation, or a silver salt solution and a halide solution are simultaneously mixed. A method of preparing silver halide grains by a method of simultaneous mixing of three liquids, a method of charging a required amount of an aqueous solution of a metal compound into a reaction vessel during grain formation, or a method of mixing silver halides. There is a method in which another silver halide grain doped with metal ions or complex ions in advance during the preparation is added and dissolved. In particular, an aqueous solution of a metal compound or a metal compound and NaC
1, a method of adding an aqueous solution in which KCl is dissolved together to a water-soluble halide solution is preferable. When adding to the particle surface, a required amount of an aqueous solution of a metal compound can be charged into the reaction vessel immediately after the formation of the particles, during or at the end of physical ripening, or at the time of chemical ripening.

The photosensitive silver halide grains can be desalted by a known desalting method such as a noodle method, flocculation method, ultrafiltration method, and electrodialysis method.

The photosensitive silver halide grains in the present invention are preferably chemically sensitized. Examples of the sensitization method include known methods such as sulfur sensitization, selenium sensitization, tellurium sensitization, noble metal sensitization, and reduction sensitization. A sensitization method can be used. These sensitization methods can be used in combination of two or more. For sulfur sensitization, thiosulfates, thiourea compounds, inorganic sulfur and the like can be used. Compounds preferably used for selenium sensitization and tellurium sensitization are described in JP-A-9-2.
The compounds described in No. 30527 can be mentioned.

Compounds preferably used in the noble metal sensitization method include, for example, chloroauric acid, potassium chloroaurate, potassium aurithiocyanate, gold sulfide, gold selenide, US Pat. No. 2,448,060, British Patent No. 618061 and the like. Can be mentioned. As the shell-like compound in the reduction sensitization method, ascorbic acid, thiourea dioxide, stannous chloride, hydrazine derivatives, borane compounds, silane compounds, polyamine compounds and the like can be used. Further, reduction sensitization can be performed by ripening the emulsion while maintaining the pH of the emulsion at 7 or more or the pAg at 8.3 or less.

In the photothermographic material of the present invention, dyes such as cyanine, merocyanine, complex cyanine, complex merocyanine, holopolar cyanine, styryl, hemicyanine, oxonol and hemioxonol can be used as spectral sensitizing dyes. In particular, a sensitizing dye having a spectral sensitivity suitable for the spectral characteristics of the light source of various laser imagers and scanners can be advantageously selected, for example, JP-A-9-34078 and JP-A-9-544.
No. 09 and No. 9-80679 are preferably used.

These sensitizing dyes may be used alone or in combination, and the combination of sensitizing dyes is often used particularly for supersensitization. Along with 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,
A combination of a dye exhibiting supersensitization and a substance exhibiting supersensitization are described in Research Disclosure (RD) 17643 (19).
This is described in section J on page 23, 1V, or the aforementioned JP-B Nos. 9-25500 and 43-4933, JP-A-59-19032 and JP-A-59-192242.

In the present invention, the organic silver salt is a reducible silver source, and a silver salt of an organic acid or a heteroorganic acid containing a reducible silver ion source, especially a long chain (10 to 30, preferably 15 to 28) The silver salt of an aliphatic carboxylic acid having (the number of carbon atoms) is preferred. Organic or inorganic silver salt complexes wherein the ligand has a complex stability constant for silver ions of 4.0 to 10.0 are also useful. For example: silver salts of organic acids (eg, gallic, oxalic, behenic, stearic, palmitic, lauric, oleic, caproic, myristic, palmitic, maleic, linoleic) Carboxyalkylthiourea salt of silver (for example,
1- (3-carboxypropyl) thiourea, 1- (3-
Carboxypropyl) -3,3-dimethylthiourea; silver complexes of polymer reaction products of aldehydes with hydroxy-substituted aromatic carboxylic acids (eg, aldehydes (formaldehyde, acetaldehyde, butyraldehyde, etc.), hydroxy-substituted acids (eg, , Salicylic acid,
Benzoic acid, 3,5-dihydroxybenzoic acid, 5,5-thiodisalicylic acid), silver salts or complexes of thioenes (for example, 3- (2-carboxyethyl) -4-hydroxymethyl-4- (thiazoline-2) -Thioene and 3-carboxymethyl-4-thiazoline-2-thioene), imidazole, pyrazole, urazole, 1,2,4-thiazole and 1H-tetrazole, 3-amino-5-benzylthio-1,2,4- Complexes or salts of silver with a nitrogen acid selected from triazoles and benzotriazoles; silver salts such as saccharin, 5-chlorosalicylaldoxime; and silver salts of mercaptides, examples of suitable silver salts being (RD)
17029 and 29996, a particularly preferred silver source is silver behenate.

The organic silver salt compound can be obtained by mixing a water-soluble silver compound and a compound which forms a complex with silver, and can be obtained by a forward mixing method, a reverse mixing method, a simultaneous mixing method, and a method described in JP-A-9-12764.
A controlled double jet method as described in No. 3 is preferably 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. As is well known in photosensitive silver halide photosensitive materials, the inverse relationship between the size of silver salt crystal grains and their covering power also holds in the photothermographic material of the present invention. When the size of the organic silver salt particles as the image forming portion is large, it means that the covering power is small and the image density is low. Therefore, it is necessary to reduce the size of the organic silver salt. In the present invention, the short axis 0.
It is preferably from 0.01 μm to 0.20 μm, from 0.10 μm to 5.0 μm on the long axis, and from 0.01 μm to 0.1 μm on the short axis.
More preferably, it is 15 μm or less, and the major axis is 0.10 μm or more and 4.0 μm or less. The particle size distribution of the organic silver salt is preferably monodispersed. Monodispersion means 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, preferably 100% or less, more preferably 80% or less, and still more preferably 50% or less. Is good.

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 for 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) of the value divided by the volume-weighted average diameter is preferably 100% or less. It is preferably at most 80%, more preferably at most 50%. As a measuring method, for example, an organic silver salt dispersed in a liquid is irradiated with a laser beam, and the autocorrelation coefficient with respect to the time change of the fluctuation of the scattered light is obtained from the particle size (volume weight average diameter) obtained. be able to.

The coating amount of the organic silver salt, in particular an organic acid silver in the photosensitive material of the present invention the photosensitive material 1 m ² per 0.5 to 5.
0 g is preferable, and 1.0-3.0 g is more preferable.

Examples of reducing agents suitable for the photothermographic material of the present invention are described in US Pat. Nos. 3,770,448 and 3,773.
No. 3,512, No. 3,593,863, and (R
D) 17029 and 29996, and include:

Aminohydroxycycloalkenone compounds (eg, 2-hydroxypiperidino-2-cyclohexenone); aminoreductones esters (eg, piperidinohexose reductone monoacetate) as precursors of reducing agents An N-hydroxyurea derivative (for example, Np-methylphenyl-N
Hydrazones of aldehydes or ketones (e.g. anthracene aldehyde phenylhydrazone); phosphoramidophenols; phosphoramidoanilines; polyhydroxybenzenes (e.g.
Hydroquinone, t-butyl-hydroquinone, isopropylhydroquinone, and (2,5-dihydroxy-phenyl) methylsulfone); sulfhydroxamic acids (eg, benzenesulfhydroxamic acid); sulfonamidoanilines (eg, 4- (N- Methanesulfonamido) aniline); 2-tetrazolylthiohydroquinones (eg, 2-methyl-5- (1-phenyl-5-tetrazolylthio) hydroquinone); tetrahydroquinoxalines (eg, 1,2,3,4-tetrahydro) Aminooxins; Azines (for example, a combination of an aliphatic carboxylic acid arylhydrazide and ascorbic acid); a combination of polyhydroxybenzene and hydroxylamine, reductone and / or hydrazine; Hydroxanoic acids Combinations of azines and sulfonamide phenols; α-cyanophenylacetic acid derivatives; combinations of bis-β-naphthol and 1,3-dihydroxybenzene derivatives; 5-pyrazolones; sulfonamide phenol reducing agents; 2-phenylindane-1 ,
Chromanes; 1,4-dihydropyridines (for example, 2,6-dimethoxy-3,5-dicarbethoxy-1,4-dihydropyridine); bisphenols (for example, bis (2-hydroxy-3- t-butyl-5
-Methylphenyl) methane, bis (6-hydroxy-m
-Tri) mesitol, 2,2-bis (4-hydroxy-3-methylphenyl) propane,
4,5-ethylidene-bis (2-t-butyl-6-methyl) phenol), ultraviolet-sensitive ascorbic acid derivatives and 3-pyrazolidones. Among them, particularly preferred reducing agents are hindered phenols. Examples of the hindered phenols include compounds represented by the following general formula (A).

[0062]

Embedded image

In the formula, R is a hydrogen atom or a group having 1 to 1 carbon atoms.
10 alkyl group (e.g., -C ₄ H _9, 2,4,4 etc. trimethylpentyl group) represents, R 'and R "each alkyl group having 1 to 5 carbon atoms (e.g., methyl, ethyl, t-butyl group).

Specific examples of the compound represented by formula (A) are shown below. However, the present invention is not limited to the following compounds.

[0065]

Embedded image

[0066]

Embedded image

The amount of the reducing agent including the compound represented by formula (A) is preferably 1 × 1 per mol of silver.
It is 0 ^-2 to 10 mol, particularly preferably 1 × 10 ^{-2 to} 1.5 mol.

Binders suitable for the photothermographic material of 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, and polyvinyl. Alcohol, hydroxyethylcellulose, cellulose acetate, cellulose acetate butyrate, polyvinylpyrrolidone, casein, starch, polyacrylic acid, polymethylmethacrylic acid, polyvinyl chloride, polymethacrylic acid, copolystyrene-maleic anhydride, copolystyrene-acrylonitrile, copolyester Polystyrene-butadiene, polyvinyl acetal (eg, polyvinyl formal and polyvinyl butyral), polyesters, polyurethanes, phenoxy resin, polyvinylidene chloride, polyepoxy Sid, polycarbonates,
There are polyvinyl acetate, cellulose esters and polyamides. These may be hydrophilic or non-hydrophilic.

In the present invention, the amount of the binder in the photosensitive layer is preferably 1.5 to 10 for the purpose of preventing dimensional fluctuation after thermal development.
g / m ² . More preferably 1.7
８8 g / m ² . If it is less than 1.5 g / m ² , the density of the unexposed portion will increase significantly and may not be usable.

In the present invention, a matting agent is preferably contained on the photosensitive layer side, and in order to prevent the image after thermal development from being damaged, it is preferable to provide a matting agent on the surface of the photosensitive material. The matting agent is preferably contained in a weight ratio of 0.5 to 10% with respect to all binders on the emulsion layer side. The material of the matting agent used may be either an organic substance or an inorganic substance. For example, as the inorganic substance, Swiss Patent 3
Silica described in US Pat. No. 30,158, French Patent 1,296,
No. 995, British Patent 1,173,18
Alkaline earth metals or carbonates such as cadmium and zinc described in No. 1 can be used as a matting agent.

As organic substances, US Pat. No. 2,322,03
7, starch derivatives described in Belgian Patent No. 625,451 and British Patent No. 981,198, polyvinyl alcohol described in Japanese Patent Publication No. 44-3643, and Swiss Patent No. 330,158. Polystyrene or polymethacrylate, U.S. Pat. No. 3,079,
No. 257, polyacrylonitrile, 3,02
Organic matting agents such as polycarbonate described in 2,169 can be used.

The shape of the matting agent may be either regular or irregular, but is preferably regular and spherical. The size of the matting agent is represented by a diameter when the volume of the matting agent is converted into a sphere. In the present invention, the particle diameter of the matting agent indicates the diameter converted into a sphere.

The matting agent used in the present invention preferably has an average particle size of 0.5 μm to 10 μm, more preferably 1.0 μm to 8.0 μm. The matting agent has a coefficient of variation of the particle size distribution of preferably 50% or less, more preferably 40% or less, and particularly preferably 30% or less.

Here, the variation coefficient of the particle size distribution is a value represented by the following equation.

(Standard deviation of particle size) / (Average value of particle size) × 100 The matting agent can be contained in any constituent layer, but in order to achieve the object of the present invention, it is preferable to use a photosensitive layer. And more preferably the outermost layer as viewed from the support. The method of adding the matting agent may be a method in which the matting agent is dispersed in a coating solution in advance, or a method in which the matting agent is sprayed before the drying is completed after the coating solution is applied. When a plurality of types of matting agents are added, both methods may be used in combination.

The photothermographic material of the present invention, which forms a photographic image by heat development, comprises a reducible silver source (organic silver salt), a catalytically active amount of photosensitive silver halide, a reducing agent, Normal (organic) toning agent that suppresses silver tone as needed
It is preferable that the photothermographic material is contained in a state dispersed in a binder matrix.

The photothermographic material of the present invention is stable at room temperature, but is developed by heating to a high temperature (for example, 80 ° C. to 140 ° C.) after exposure. Heating generates silver through an oxidation-reduction reaction between an organic silver salt (functioning as an oxidizing agent) and a reducing agent. This oxidation-reduction reaction is accelerated by the catalytic action of the latent image generated on the silver halide upon exposure. The silver formed by the reaction of the organic silver salt in the exposed areas provides a black image, which contrasts with the unexposed areas, resulting in the formation of an image. This reaction process proceeds without supplying a processing liquid such as water from the outside.

The photothermographic material of the present invention has at least one photosensitive layer on a support. Although only a photosensitive layer may be formed on the support, it is preferable to form at least one non-photosensitive layer on the photosensitive layer. A filter layer may be formed on the same side as or opposite to the photosensitive layer to control the amount or wavelength distribution of light passing through the photosensitive layer, or the photosensitive layer may contain a dye or pigment. .

The light-sensitive layer may be composed of a plurality of layers, and the sensitivity may be changed to a high-sensitivity layer / low-sensitivity layer or a low-sensitivity layer / high-sensitivity layer for adjusting the gradation.

The various additives may be added to any of the photosensitive layer, the non-photosensitive layer, and other layers. The photothermographic material of the invention may contain, for example, a surfactant, an antioxidant, a stabilizer, a plasticizer, an ultraviolet absorber, and a coating aid.

It is preferable to add a color tone agent to the photothermographic material of the present invention. Toning agents are disclosed in US Pat.
0,254, 3,847,612 and 4,12
It is a material well known in the photographic art as described in 3,282 or the like. Examples of suitable toning agents are Research.
Disclosure (RD) 17029, and includes the following.

Imides (for example, phthalimide); cyclic imides, pyrazolin-5-ones, and quinazolinones (for example, succinimide, 3-phenyl-2-pyrazolin-5-one, 1-phenylurazole, quinazoline and 2 , 4-thiazolidinedione); naphthalimides (eg, N-hydroxy-1,8-naphthalimide); cobalt complexes (eg, hexamine trifluoroacetate of cobalt), mercaptans (eg, 3
-Mercapto-1,2,4-triazole); N- (aminomethyl) aryldicarboximides (for example,
N- (dimethylaminomethyl) phthalimide); blocked pyrazoles, isothiuronium (isoth
uronium) derivatives and certain photobleaching combinations (eg, N, N'-hexamethylene (1-carbamoyl-3,5-dimethylpyrazole), 1,8-
A combination of (3,6-dioxaoctane) bis (isothiuronium trifluoroacetate) and 2- (tribromomethylsulfonyl) benzothiazole; a merocyanine dye (for example, 3-ethyl-5- (3-ethyl- 2-benzothiazolinylidene-1-methylethylidene) -2-thio-2,4-oxazolidinedione); phthalazinone, a phthalazinone derivative or a metal salt of these derivatives (for example, 4- (1-naphthyl) phthalazinone,
6-chlorophthalazinone, 5,7-dimethyloxyphthalazinone, and 2,3-dihydro-1,4-phthalazinedione); a combination of phthalazinone and a sulfinic acid derivative (for example, 6-chlorophthalazinone and benzenesulfin) Acid or 8-methylphthalazinone and p-
Sodium trisulfonate); a combination of phthalazine and phthalic acid; phthalazine (including phthalazine adducts)
And maleic anhydride, and phthalic acid, 2,3-naphthalenedicarboxylic acid or o-phenylene acid derivative and its anhydride (eg, phthalic acid, 4-methylphthalic acid, 4-nitrophthalic acid and tetrachlorophthalic anhydride) Quinazolinediones, benzoxazines, orthoxazine derivatives; benzoxazine-2,4-diones (for example,
1,3-benzoxazine-2,4-dione); pyrimidines and asymmetric triazines (eg, 2,4-dihydroxypyrimidine), and tetraazapentalene derivatives (eg, 3,6-dimercapto-1, 4-diphenyl-1H, 4H-2,3a, 5,6a-tetraazapentalene) and the like. Preferred toning agents are phthalazone or phthalazine.

In the present invention, a mercapto compound, a disulfide compound, a thione compound and the like can be contained in order to control the development, to improve the spectral sensitization efficiency, and to improve the storage stability before and after the development. . When a mercapto compound is used in the present invention, it may have any structure, but is preferably a compound represented by the following general formula.

ArSM or Ar-SS-Ar wherein M represents a hydrogen atom or an alkali metal atom;
Represents an aromatic or fused aromatic ring having one or more nitrogen, sulfur, oxygen, selenium or tellurium atoms. The heteroaromatic ring is preferably benzimidazole, naphthimidazole, benzothiazole, naphthothiazole, benzoxazole, naphthoxazole, benzoselenazole, benzoterzole, imidazole, oxazole,
Pyrazole, triazole, thiadiazole, tetrazole, triazine, pyrimidine, pyridazine, pyrazine, pyridine, purine, quinoline or quinazolinone ring. The heteroaromatic ring is a halogen (eg, Br
And Cl), hydroxy, amino, carboxy, alkyl (e.g., having one or more carbon atoms, preferably 1-4 carbon atoms) and alkoxy (e.g., 1
Mercapto-substituted heteroaromatic compounds which may have a substituent selected from the group consisting of at least two carbon atoms, preferably those having 1 to 4 carbon atoms). Imidazole, 2-mercaptobenzoxazole, 2-mercaptobenzothiazole, 2-mercapto-5-methylbenzimidazole,
6-ethoxy-2-mercaptobenzothiazole, 2,
2'-dithiobisbenzothiazole, 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-hydroxy-2-mercaptopyrimidine, 21-mercaptopyrimidine, 4,6- Diamino-2
Mercaptopyrimidine, 2-mercapto-4-methylpyrimidine hydrochloride, 3-mercapto-5-phenyl-1,2,4-triazole, 2-mercapto-4-
Examples include phenyloxazole, but the present invention is not limited thereto.

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

What is known as the most effective antifoggant is mercury ion. The use of a mercury compound as an antifoggant in a light-sensitive material is disclosed in, for example, US Pat. No. 3,589,903. However, mercury compounds are environmentally unfriendly. Non-mercury antifoggants include, for example, US Pat. No. 4,546,075.
No. 4,452,885 and JP-A-59-572.
Antifoggants as disclosed in No. 34 are preferred.

Particularly preferred non-mercury antifoggants include US Pat. Nos. 3,874,946 and 4,756,
No. 999, wherein the compound is -C (X ₁ )
(X ₂ ) A heterocyclic compound having one or more substituents represented by (X ₃ ). (Where X ₁ and X ₂ are halogen and X ₃ is hydrogen or halogen) Examples of suitable antifoggants include JP-A-9-9055
Compounds and the like described in No. 0 paragraph numbers [0062] to [0063] are preferably used.

Further, more suitable antifoggants are disclosed in US Pat. No. 5,028,523 and British Patent Application 9222138.
Nos. 3.4, 9300147.7 and 931179
No. 0.1.

In the photosensitive layer according to the invention, a polyhydric alcohol (for example, US Pat.
Glycerin and diols of the type described in U.S. Pat. No. 0,404), U.S. Pat. Nos. 2,588,765 and 3,12
Fatty acids or esters described in U.S. Pat.
No. 55,061 can be used.

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 the hardener include isocyanate compounds and those described in US Pat. No. 4,791,042. Epoxy compounds disclosed in
For example, vinylsulfone-based compounds described in JP-A-89048 and the like are used.

In the present invention, a surfactant may be used for the purpose of improving coating properties and charging. As an example of the surfactant, any of anionic, cationic, betaine, nonionic, and fluorine-based surfactants can be appropriately used. Specifically, JP-A-62-170950, U.S. Pat.
82,504, etc., fluorine-containing polymer surfactants described in JP-A-60-244945 and JP-A-63-18813.
No. 5 and the like, US Pat.
85,965 and the like, and polyalkylene oxides and anionic surfactants described in JP-A-6-301140 and the like.

The photothermographic material of the present invention can be coated by various coating methods including a dip coating method, an air knife coating method, a flow coating method, and an extrusion coating method using a hopper of the type described in US Pat. No. 2,681,294. Can be used. If necessary, two or more layers can be applied simultaneously by the methods described in US Pat. No. 2,761,791 and British Patent 837,095.

The support used in the present invention may be a plastic film (for example, polyethylene terephthalate, polycarbonate, polyimide, nylon, cellulose triacetate) in order to obtain a predetermined optical density after development and to prevent image deformation after development. , Polyethylene naphthalate).

Among them, preferred supports include plastics (hereinafter abbreviated as SPS) containing polyethylene terephthalate (hereinafter abbreviated as PET), polyethylene naphthalate (hereinafter abbreviated as PEN), and a styrene polymer having a syndiotactic structure. Support.
The thickness of the support is about 50 to 300 μm, preferably 70 to 180 μm.

A plastic support which has been heat-treated can also be used. The plastics to be employed include the above-mentioned plastics. The heat treatment of the support means that after forming these supports and before the photosensitive layer is applied, at a temperature higher than the glass transition point of the support by 30 ° C. or more,
Preferably at a temperature higher than 35 ° C., more preferably 40 ° C.
It is preferable to heat at a temperature higher than ℃.

Next, the plastic used will be described. PET is made of polyethylene terephthalate in which all of the polyester components are used. In addition to polyethylene terephthalate, terephthalic acid, naphthalene-2,6-dicarboxylic acid, isophthalic acid, butylene dicarboxylic acid, 5-sodium sulfoisophthalic acid are used as acid components.
A polyester containing a modified polyester component of adipic acid or the like and a glycol component such as ethylene glycol, propylene glycol, butanediol, cyclohexanedimethanol or the like in an amount of 10 mol% or less of the entire polyester may be used.

As PEN, polyethylene-2,6-
Preference is given to naphthalate, copolymerized polyesters comprising terephthalic acid, 2,6-naphthalenedicarboxylic acid and ethylene glycol, and polyesters whose main constituent is a mixture of two or more of these polyesters. Further, another copolymerization component may be copolymerized,
Other polyesters may be mixed.

SPS is a polystyrene having steric regularity unlike ordinary polystyrene (atactic polystyrene). The regular stereoregular structure part of the SPS is called a racemo chain, and it is preferable that there are more regular parts such as two, three, five, or more. 75 in 3 chains
% Or more, 50% or more for 5 chains, 30% for more chains
It is preferable that it is above. The polymerization of SPS is disclosed in
The method can be performed according to the method described in No. 131843.
Known methods can be used for the method of forming the support and the method of producing the undercoat. Preferably, the method is described in JP-A-9-50094.
That is, the method described in paragraphs [0030] to [0070] is used.

[0099]

EXAMPLES The present invention will be described below in detail with reference to examples, but embodiments of the present invention are not limited thereto.

Example 1 (Preparation of photosensitive silver halide emulsion A) 7.5 g of inert gelatin and 10 mg of potassium bromide were dissolved in 900 ml of water, the temperature was adjusted to 35 ° C. and the pH was adjusted to 3.0, and then silver nitrate was added. 370 ml of an aqueous solution containing 74 g of potassium bromide and potassium iodide in a molar ratio of (98/2) and Ir (NO) Cl
₅ ] A salt was added by a controlled double jet method while maintaining an aqueous solution containing 1.times.10.sup.- ⁶ mol per mol of silver at a pAg of 7.7.

Thereafter, 4-hydroxy-6-methyl-1,
3,3a, 7-Tetrazaindene was added, and the pH was adjusted to 5 with NaOH to obtain a cubic iodobromide having an average grain size of 0.06 μm, a variation coefficient of the projected diameter area of 8%, and a [100] face ratio of 87%. Silver particles were obtained.

This emulsion was subjected to coagulation sedimentation using a gelatin coagulant and desalting treatment, and 0.1 g of phenoxyethanol was added to adjust the pH to 5.9 and the pAg to 7.5 to obtain a silver halide emulsion. Next, 3 × 10 ^-2 moles of hypo per mole of silver were added to the silver halide emulsion, and 6
The mixture was allowed to react for 0 minutes to perform chemical sensitization.

Thereafter, the temperature of the silver halide emulsion was lowered to room temperature, and then the following general formulas (1) and (2)
A light-sensitive silver halide emulsion was prepared by adding the above compound.

Next, according to the method of Example 1 of JP-A-9-127463, silver behenate was prepared by the following method.

(Preparation of Na Behenate Solution) 34 g of behenic acid was dissolved in 340 ml of isopropanol at 65 ° C. Next, while stirring, a 0.25N aqueous sodium hydroxide solution was added so as to have a pH of 8.7. At this time, about 400 ml of the sodium hydroxide aqueous solution was required. Next, the aqueous sodium behenate solution was concentrated under reduced pressure to adjust the concentration of sodium behenate to 8.9% by weight.

(Preparation of Silver Behenate) 2.9 ml of a solution prepared by dissolving 30 g of ossein gelatin in 750 ml of distilled water.
A 4M silver nitrate solution was added to adjust the silver potential to 400 mV. 78 ° C using a controlled double jet method
At the same temperature, 374 ml of the sodium behenate solution was added, and at the same time, a 2.94 M silver nitrate aqueous solution was added. The amounts of sodium behenate and silver nitrate used at the time of addition were 0.092 mol and 0.101 mol, respectively.

After completion of the addition, the mixture was further stirred for 30 minutes, and the water-soluble salts were removed by ultrafiltration.

(Preparation of Photosensitive Emulsion) To this silver behenate dispersion, 0.01 mol of the above-mentioned silver halide emulsion was added, and while stirring, a solution of polyvinyl acetate in n-butyl acetate (1.
100 g was gradually added to form a floc of the dispersion, water was removed, water was washed twice and water was removed, and 2.5 wt% of polyvinyl butyral (average molecular weight 3000) was used as a binder. 60 g of a 1: 2 mixed solution of butyl acetate and isopropyl alcohol was added with stirring, and polyvinyl butyral (average molecular weight 4000) and isopropyl alcohol were added as binders to the gel-like mixture of silver behenate and silver halide thus obtained. Was added and dispersed.

The following layers were sequentially formed on a blue-colored PET support to prepare a sample. In addition, each drying is 75
C. for 5 minutes.

<Backing Layer> A liquid having the following composition was applied so as to have a wet thickness of 80 μm.

Polyvinyl butyral (10% isopropanol solution) 150 ml Dye-B 70 mg

[0112]

Embedded image

<Photosensitive layer> A solution having the following composition was applied so that the coated silver amount was 2.0 g / m ² and polyvinyl butyral as a binder was 6.5 g / m ² .

Photosensitive Silver Halide Emulsion A An amount that gives 0.1 g / m ² in terms of silver amount Silver behenate An amount that gives 1.9 g / m ² in terms of silver amount Sensitizing dye-1 (0.1% DMF solution) 2 mg Antifoggant-1 (0.01% methanol solution) 3 ml Antifoggant-2 (1.5% methanol solution) 8 ml Antifoggant-3 (2.4% DMF solution) 5 ml Phthalazone (4.5% DMF) Solution) 8 ml Developer-1 (10% acetone solution) 13 ml Compound of general formula (1) Amount described in Table 1 Compound of general formula (2) Amount described in Table 1

[0115]

Embedded image

[0116]

Embedded image

<Protective layer> A solution having the following composition was wetted to a thickness of 10
It was applied on the photosensitive layer so as to have a thickness of 0 μm.

Acetone 175 ml 2-propanol 40 ml methanol 15 ml cellulose acetate 8.0 g phthalazine 1.0 g 4-methylphthalic acid 0.72 g tetrachlorophthalic acid 0.22 g tetrachlorophthalic anhydride 0.5 g monodisperse having an average particle size of 4 μm 1% (W / W) based on silica binder << Sensitivity measurement >> 760 was added to the photothermographic material prepared above.
The step wedge image was exposed using a laser imager having a nm semiconductor laser. Thereafter, heat development was performed at 110 ° C. for 15 seconds using an automatic developing machine having a heat drum. At that time, exposure and development are 23 ° C, 50%
Performed in a room conditioned to RH. The sensitivity value is (Fog +
1.0) was determined as the reciprocal of the exposure required to obtain the density of Sample No. 1.0). The sensitivity of 1 was set to 100 and expressed as relative sensitivity.

<< Evaluation of Fog Density after Thermal Development >> The above-mentioned thermally developed sample used for the sensitivity measurement was divided into two samples, one of which was 5%.
It was put into a thermo machine at 0 ° C. and 50% RH for 5 days. The other was left in a room at 23 ° C. and 50% RH for 5 days, and the difference in fog density between the two samples was evaluated.

(Fog density difference) = (fog of sample stored at 50 ° C. thermo machine) − (fog of sample stored at 23 ° C.) The fog density as referred to herein means the fog density of an unexposed portion. The smaller the value, the better the storability of the image.

<< Evaluation of Silver Tone After Thermal Development >> The silver tone of the exposed portion of the above sample placed in a thermo machine at 50 ° C. was visually evaluated for rank. The cold black tone was set to 5, and gradually decreased to 4,3,2,1 as the warm black tone was reached. 1 was a brownish color which was not excellent, and 1 to 3 was a color which was not practical.
Table 1 shows the results of the evaluation.

[0122]

[Table 1]

As is clear from the table, the sample of the present invention is excellent in the long-term storage stability of the image after heat development and silver tone.

[0124]

As has been demonstrated in the examples, according to the present invention, a photosensitive material for thermal development having excellent storage stability of images after thermal development and excellent silver tone can be provided.

Claims (1)

[Claims] 1. A photothermographic material having an organic silver salt, photosensitive silver halide particles and a reducing agent on a support, wherein at least one compound represented by the following general formula (1) is contained in the photosensitive material. And a photothermographic material comprising at least one compound represented by the following general formula (2). Embedded image (Wherein, Y ^1, Y ² each represent a nitrogen atom or CR _2, R ₂
Represents a hydrogen atom, a substituted or unsubstituted alkyl group, or a substituted or unsubstituted aryl group. R ₁ represents a (one or more) sulfo group or a salt thereof, a carboxy group or a salt thereof, a substituted or unsubstituted aminoalkyl group, a hydroxy group or an aryl group substituted with a boron residue. M ₁ represents a hydrogen atom, an alkali metal atom, or an ammonium group. ) (Wherein, Y ^3, Y ⁴ each represent a nitrogen atom or a CR _4, R ₄
Represents a hydrogen atom, a substituted or unsubstituted alkyl group, or a substituted or unsubstituted aryl group. R ₃ is a sulfo group or a salt thereof,
A carboxy group or a salt thereof, an acylamino group, a hydroxy group or an alkyl group having 1 to 20 carbon atoms substituted with a boron residue. M ₂ represents a hydrogen atom, an alkali metal atom, or an ammonium group. )