JP2000039685A - Heat developable photosensitive material - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a heat developable photosensitive material which has resistance against an abrasion and high sensitivity and in which the colortone of an image is pure black. SOLUTION: In this heat developable photosensitive material having a photosensitive layer containing org. silver salts, a fogging preventing agent and photosensitive silver halide particles on at least one surface on a supporting body, the photosensitive layer or other layers contain a dye having 520 to 580 nm max. absorption wavelength. Preferably, the dye above described is incorporated by being dispersed in a high boiling solvent or by being dispersed in a solid.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a photothermographic material.

[0002]

2. Description of the Related Art In recent years, it has been strongly desired in the medical field to easily perform exposure from the viewpoint of environmental protection and space saving, and to reduce the amount of processing waste liquid. Thus, a photothermographic photo for medical diagnosis and photographic technology, which can be efficiently exposed by a laser imagesetter or laser imager and can form a black image having high resolution and sharpness. There is a need for materials technology. These photothermographic materials can eliminate the use of solution processing chemicals and provide a simpler and more environmentally friendly thermal development system to customers.

[0003] In a photosensitive material for directly observing a silver image, the color tone of the formed silver image is extremely important, and discoloration or coloring contamination gives a viewer an unpleasant impression. It is strongly required that a clear image with a pure black tone can be stably obtained. In addition, plate-shaped photosensitive silver, which will be frequently used for the purpose of saving silver and high image quality, tends to have a warm black color in the obtained silver image, and since the photothermographic material is not processed in a wet process,
Photosensitive silver also remains in the non-image area, which may become yellow over time. Therefore, it is desired to control the color tone of the silver image by coloring the photographic constituent layer. In addition, since the photothermographic material is pressed against a drum heated to a high temperature, a scratch inhibitor which does not affect the photosensitive layer is also desired.

[0004]

SUMMARY OF THE INVENTION An object of the present invention is to provide a high-sensitivity photothermographic material having abrasion resistance and a pure black image.

[0005]

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

(1) At least one surface on the support,
In a photothermographic material having a photosensitive layer containing an organic silver salt, an antifogging agent and photosensitive silver halide grains, the photosensitive layer or another layer has a maximum absorption wavelength of 520 to 580 nm.
A photothermographic material comprising a dye.

(2) The maximum absorption wavelength is 520 to 580 nm
The photothermographic material according to (1), wherein the dye is dispersed in a high-boiling-point solvent.

(3) The maximum absorption wavelength is 520 to 580 nm
The photothermographic material according to the above (1), wherein the dye is dispersed in a solid form.

Hereinafter, the present invention will be described in detail.

As the dye used in the present invention, a dye having a maximum absorption wavelength of 520 to 580 nm is used. Examples of the dye corresponding thereto include anthraquinone dye, azo dye, azomethine dye, oxonol dye, carbocyanine dye, styryl dye, and the like.

In order to incorporate the dye used in the present invention into a photothermographic material, there are a method in which the dye is dispersed in a high boiling point solvent and a method in which the dye is solid-dispersed as a solid fine particle dispersion.

The dyes dispersed and contained in the high-boiling solvent are specifically shown below, but are not limited thereto.

[0013]

Embedded image

[0014]

Embedded image

[0015]

Embedded image

[0016]

Embedded image

[0017]

Embedded image

[0018]

Embedded image

[0019]

Embedded image

In order to disperse the dye in the high boiling solvent, the dye is dissolved in a substantially water-insoluble high boiling solvent, if necessary, in combination with a low boiling solvent or a water-soluble solvent, and a colloid mill, a homogenizer, The mixture can be added by emulsification and dispersion using an emulsifying device such as an ultrasonic dispersing device.

The high-boiling solvents of the present invention include carboxylic esters, phosphoric esters, carboxylic amides,
Ethers, substituted hydrocarbons, etc., and specifically, di-n-butyl phthalate, di-isooctyl phthalate, dimethoxyethyl phthalate, di-n-butyl adipate Di-isooctyl azelate, tri-n-butyl citrate, butyl laurate, di-n-
Butyl sebacate, tricresyl phosphate, tri-n-butyl phosphate, triisooctyl phosphate, N, N'-diethylcaprylic amide, N, N'-dimethylpalmitic amide, n-butyl-pentadecyl Phenyl ether, ethyl-2,4-
Examples include tert-butylphenyl ether, succinate, maleate, and paraffin chloride, and these can be used alone or in combination of two or more.

A low-boiling organic solvent which can be used;
As the water-soluble solvent, ethyl acetate, butyl acetate, cyclohexane, propylene carbonate, methanol, se
There are c-butyl alcohol, tetrahydrofuran, dimethylformamide, benzene, chloroform, acetone, methyl ethyl ketone, dimethyl sulfoxide methyl cellosolve and the like, and one or more of these can be used as necessary.

The dyes to be solid-dispersed in the present invention are specifically shown below, but are not limited thereto.

[0024]

Embedded image

[0025]

Embedded image

[0026]

Embedded image

[0027]

Embedded image

[0028] The solid fine particles in the present invention mean a state of existence as a solid having a size that is substantially impossible to diffuse in a layer. The solid fine particle dispersion of the dye can be formed by a known pulverization method (for example, a ball mill, a vibration ball mill, a planetary ball mill, a sand mill, a colloid mill, a jet mill) in the presence of a dispersant. At that time, a solvent (for example, water or ethyl alcohol) may coexist. Also, after dissolving the dye of the present invention in a suitable solvent,
The poor solvent of the dye of the present invention may be added to precipitate microcrystalline powder, and in this case, a dispersing surfactant may be used. Alternatively, by controlling the pH,
First, it may be dissolved, and then the pH may be changed for microcrystallization.

The photothermographic material of the present invention is disclosed in, for example, US Pat. Nos. 3,152,904 and 3,457,075.
And D. Morgan (Dry Silver Photogr)
aphic Material) "and D.A. Morgan (M
organ) and B.C. "The Silver System Treated by Heat (Thermally)" by Shelly
ProcessedSilverSystems) "
(Imaging Processes and Materials
materials) Neblette Eighth Edition, Sturge, V.A. Walworth
rth), A. Shepp Editing, Page 2,
1969).

Among them, it is preferable to form an image by thermally developing a photosensitive material at 80 to 140 ° C. without fixing. In this case, the silver halide and the organic silver salt remaining in the unexposed portions remain in the photosensitive material without being removed.

The silver halide grains in the present invention preferably have a small average grain size in order to suppress white turbidity after image formation and obtain good image quality, and the average grain size is preferably 0.1 μm or less, more preferably 0.01-0.
1 μm, particularly preferably 0.02 to 0.08 μm. The term "grain size" as used herein refers to the length of a ridge of a silver halide grain when the silver halide grain is a cubic or octahedral so-called normal crystal. In the case of non-normal crystals, for example, in the case of spherical, rod-shaped or tabular grains, it refers to the diameter of a sphere equivalent to the volume of silver halide grains. Further, the silver halide is 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 to 20%.

Monodispersity = (standard deviation of grain size) / (average grain size) × 100 In the present invention, the silver halide grains have an average grain size of 0.1.
μm or less and more preferably monodisperse particles,
By setting it in this range, the granularity of the image is also improved.

The shape of the silver halide grains is not particularly limited, but it is preferable that the ratio occupied by the Miller index [100] plane is high, and this ratio is 50% or more, further 70% or more, particularly 80% or more. Preferably, there is. The ratio of the Miller index [100] plane is [11] in the adsorption of the sensitizing dye.
T] utilizing the adsorption dependency between the [1] plane and the [100] plane. T
ani, J .; Imaging Sci. , 29,165
(1985).

Preferred silver halide shapes are tabular grains. The term "tabular grains" as used herein refers to those having an aspect ratio = r / h of 3 or more when the thickness in the vertical direction is h [mu] m where the square root of the projected area is r [mu] m. Among them, the aspect ratio is preferably 3 or more and 50 or less.
The particle size is preferably 0.1 μm or less, and more preferably 0.01 to 0.08 μm. These are U.S. Patent Nos. 5,264,337 and 5,314,798,
No. 5,320,958, and the like, and desired tabular grains can be easily obtained. When these tabular grains are used in the present invention, the sharpness of an image is further improved.

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. The photographic emulsion used in the present invention is P.I. Chimie et by Glafkids
Physique Photographique (P
aul Montel, 1967); F. D
Photographic Emuls by uffin
ion Chemistry (The Focal P
Res., 1966); L. Zelikman
Making and Coating by et al
Photographic Emulsion (Th
e Focal Press, 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 of a one-side mixing method, a double-mixing method, a combination thereof and the like. May be used. 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 used in the present invention preferably contains ions or complex ions of a metal belonging to Groups 6 to 10 of the periodic table. The above metals include W, Fe, Co, Ni, Cu, Ru, Rh, P
d, Re, Os, Ir, Pt, and Au are preferred.

These metals can be introduced into the silver halide in the form of a complex. In the present invention, the transition metal complex is preferably a six-coordinate complex represented by the following general formula.

In the formula [ML ₆ ] ^m , M is a transition metal selected from the elements of Groups 6 to 10 of the periodic table, L is a bridging ligand, and m is 0, -1, -2 or-.
3 is represented. 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.

Particularly preferred examples of M are rhodium (Rh), ruthenium (Ru), rhenium (Re), iridium (Ir) and osmium (Os).

The following are specific examples of the transition metal coordination complex.

[0042] 1: [RhCl _6] ^3- 2: [RuCl _6] ^3- 3: [ReCl _6] ^3- 4: [RuBr _6] ^3- 5: [OsCl _6] ^3- 6: [IrCl _6] ^{4 -} 7: [Ru (NO) Cl _5] ^2- 8: [RuBr ₄ (H ₂ O)] ^2- 9: _{[Ru (NO) (H 2 O} ) Cl 4 ] ^- 10: [RhCl ₅ (H ₂ O)] ^2-11 : [Re (NO) Cl ₅ ] ^2-12 : [Re (NO) (CN) ₅ ] ^2-13 : [Re (NO) Cl (CN) ₄ ] ^2-14 : [Rh _(NO) 2 Cl _4] ^- 15: _{[Rh (NO) (H 2 O} ) Cl 4 ] ^- 16: [Ru (NO) (CN) _5] ^2- 17: [Fe (CN) _6] ^3- 18 : [Rh (NS) Cl _5] ^2- 19: [Os (NO) Cl _5] ^2- 20: [Cr (NO) Cl _5] ^2- 21: [Re (NO) Cl _5] ^- 22: [Os (NS) Cl ₄ (TeCN ^2- 23: [Ru (NS) Cl _5] ^2- 24: _{[Re (NS) Cl 4 (SeCN} ) ] ^2- 25: [Os (NS) Cl (SCN) 4 ] ^2- 26: [Ir ( NO) Cl _5] ^2- 27: [Ir (NS) Cl _5] ^2- also may with ions or complex ions one kind of these metals, the metal of the same kind of metal or different may be used alone or in combination . The content of these metal ions or complex ions is generally 1 × 10 ⁻⁹ per mol of silver halide.
~ 1 × 10 ^-2 mol is suitable, preferably 1 × 10 ^-8 mol.
１1 × 10 ^-4 mol. The compound that provides the ion or complex ion of these metals is preferably added during silver halide grain formation and incorporated into the silver halide grains. Preparation of silver halide grains, that is, nucleation, growth, and physical ripening It may be added at any stage before and after chemical sensitization, but is particularly preferably added at the stage of nucleation, growth, and physical ripening, more preferably at the stage of nucleation and growth. Preferably, it is added at the stage of nucleation.
In the addition, it may be added in several portions, may be added uniformly in the silver halide grains, or may be added to the silver halide grains as described in JP-A-63-29603 and JP-A-2-3062.
No. 36, No. 3-167545, No. 4-76534,
As described in JP-A-6-110146, JP-A-5-273683, and the like, the particles can be contained in the particles with a distribution. Preferably, a distribution can be provided 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). A method of adding an aqueous solution of a powder or an aqueous solution in which a metal compound and NaCl and KCl are dissolved together to a water-soluble silver salt solution or a water-soluble halide solution during grain formation, or a method in which a silver salt solution and a halide solution are used. When they are mixed simultaneously, they are added as a third aqueous solution to prepare silver halide grains by a three-liquid simultaneous mixing method, a method in which a required amount of an aqueous solution of a metal compound is charged into a reaction vessel during grain formation, or a method in which halogen is added. There is a method in which another silver halide grain doped with a metal ion or a complex ion in advance at the time of preparing silver halide is added and dissolved.

In particular, a method of adding an aqueous solution of a powder of a metal compound or an aqueous solution in which a metal compound and NaCl and KCl are dissolved together is added to a water-soluble halide solution. 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 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, diacyl tellurides, bis (oxycarbonyl) ditellurides, bis (carbamoyl) ditellurides, Compounds having a P = Te bond, tellurocarboxylates, Te-organyltellurocarboxylates, di (poly) tellurides, tellurides, tellurols, telluroacetals, tellurosulfonates, having a P-Te bond Compounds, Te-containing heterocycles,
Tellurocarbonyl compounds, inorganic tellurium compounds, colloidal tellurium, and the like can be used. Compounds preferably used in the noble metal sensitization method include, for example, chloroauric acid, potassium chloroaurate, potassium aurithiocyanate, gold sulfide, gold selenide, and US Pat.
No. 48,060 and British Patent No. 618,061 can be preferably used.

As specific compounds for the reduction sensitization method, in addition to ascorbic acid and thiourea dioxide, for example, stannous chloride, aminoiminomethanesulfinic acid, hydrazine derivatives, borane compounds, silane compounds, polyamine compounds and the like are used. be able to. Further, reduction sensitization can be achieved by ripening the emulsion while maintaining the pH of the emulsion at 7 or more or the pAg at 8.3 or less. Further, reduction sensitization can be achieved by introducing a single addition portion of silver ion during grain formation.

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, particularly a long chain (10 to 30, preferably 15 to 25, And the nitrogen-containing heterocycle is preferred. Organic or inorganic silver salt complexes wherein the ligand has a total stability constant for silver ions of 4.0 to 10.0 are also useful.

An example of a suitable silver salt is Research D
No. 17029 and 29996, and include: salts of organic acids (eg, salts of gallic acid, oxalic acid, behenic acid, arachidic acid, stearic acid, palmitic acid, lauric acid, etc.); silver (E.g., 1- (3-carboxypropyl) thiourea, 1- (3-carboxypropyl) -3,3-dimethylthiourea); a polymer reaction formed between an aldehyde and a hydroxy-substituted aromatic carboxylic acid Silver complex (for example, aldehydes (formaldehyde,
Acetaldehyde, butyraldehyde, etc.), hydroxy-substituted acids (e.g., salicylic acid, benzoic acid, 3,5-dihydroxybenzoic acid, 5,5-thiodisalicylic acid), silver salts or complexes of thioenes (e.g., 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 and nitrogen acids selected from triazoles and benzotriazoles; silver salts such as saccharin and 5-chlorosalicylaldoxime; and silver salts of mercaptides. Preferred silver sources are silver behenate, silver arachidate and / or silver stearate.

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 includes a forward mixing method, a reverse mixing method, a simultaneous mixing method, and a method disclosed in JP-A-9-12764.
A controlled double jet method as described in No. 3 is preferably used. For example, an organic acid alkali metal salt soap (eg, sodium hydroxide, potassium hydroxide, etc.)
After preparing sodium behenate, sodium arachidate, etc., the above-mentioned soap and silver nitrate are added by a control double jet to produce organic silver salt crystals. At that time, silver halide grains may be mixed.

In the present invention, the organic silver salt has an average particle size of 1
It is preferably not more than μm and monodispersed. The average particle size of the organic silver salt refers to the diameter of a sphere equivalent to the volume of the organic silver salt particles when the particles of the organic silver salt are, for example, spherical, rod-shaped, or tabular particles. The average particle size is preferably 0.01 to 0.8 μm, particularly 0.05 to 0.5 μm.
μm is preferred. The monodispersion has the same meaning as that of silver halide, and preferably has a monodispersity of 1 to 30.
In the present invention, the organic silver salt is more preferably monodisperse particles having an average particle size of 1 μm or less. By setting the content in this range, an image having a high density can be obtained. Further, the organic silver salt preferably has tabular grains having 60% or more of the total organic silver.
In the present invention, the tabular grains mean those having an aspect ratio (abbreviated as AR) of 3 or more, which is a ratio between the average particle diameter and the thickness, that is, the following formula.

AR = average particle diameter (μm) / thickness (μm) In order to form organic silver into these shapes, the organic silver crystal is obtained by dispersing and pulverizing a binder or a surfactant with a ball mill or the like. Can be

In the present invention, in order to prevent devitrification of the light-sensitive material, the total amount of silver halide and organic silver salt is preferably 0.5 g or more and 2.2 g or less per m ² in terms of silver. With this range, a high-contrast image can be obtained. The amount of silver halide relative to the total amount of silver is 5 by weight.
0% or less, preferably 25% or less, more preferably 0.1% or less.
It is between 1 and 15%.

The photothermographic material of the present invention preferably contains a reducing agent. Examples of suitable reducing agents are described in U.S. Patent Nos. 3,770,448, 3,773,512, 3,593,863, and Research Dis.
Closure Nos. 17029 and 29996, and include:

Aminohydroxycycloalkenones (eg, 2-hydroxy-3-piperidino-2-cyclohexenone); aminoreductone esters (eg, piperidinohexose reductone monoacetate) as a developer precursor; N-hydroxy Urea derivatives (eg, Np-methylphenyl-N-hydroxyurea);
Aldehyde or ketone hydrazones (e.g., anthracene aldehyde phenylhydrazone); phosphoramidophenols; phosphoramidoanilines; polyhydroxybenzenes (e.g., hydroquinone, t-butyl-hydroquinone, isopropylhydroquinone and (2,5- Dihydroxyphenyl) methylsulfone);
Sulfhydroxamic acids (eg, benzenesulfhydroxamic acid); sulfonamidoanilines (eg, 4
-(N-methanesulfonamido) aniline); 2-tetrazolylthiohydroquinones (for example, 2-methyl-5
-(1-phenyl-5-tetrazolylthio) hydroquinone); tetrahydroquinoxalines (e.g., 1,2,2
Amides; aliphatic carboxylic acid aryl hydrazides and ascorbic acid; polyhydroxybenzene and hydroxylamine; reductone and / or hydrazine; hydroxanoic acids; azines and sulfones Combinations of amidophenols; α-cyanophenylacetic acid derivatives; combinations of bis-β-naphthol and 1,3-dihydroxybenzene derivatives; 5-pyrazolones; sulfonamidophenol reducing agents; 2-phenylindane-1,3-dione Chromans; 1,4-dihydropyridines (eg, 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-tolyl) mesitol, 2,2-bis (4-hydroxy-3-methylphenyl) propane,
4,4-ethylidene-bis (2-t-butyl-6-methylphenol), 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 (C).

[0057]

Embedded image

In the formula, R is a hydrogen atom or a group having 1 to 1 carbon atoms.
Represents an alkyl group of 10 (eg, butyl, 2,4,4-trimethylpentyl, etc.), and R ′ and R ″ represent an alkyl group having 1 to 5 carbon atoms (eg, methyl, ethyl,
each group such as t-butyl).

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

[0060]

Embedded image

[0061]

Embedded image

The amount of the reducing agent including the compound represented by the general formula (C) is preferably 1 × 1 per mol of silver.
It is from 0 ^-2 to 10 mol, especially from 1 x 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 polystyrene. (Vinyl alcohol), hydroxyethyl cellulose, cellulose acetate, cellulose acetate butyrate, poly (vinyl pyrrolidone), casein, starch, poly (acrylic acid), poly (methyl methacrylic acid), poly (vinyl chloride), poly (methacrylic acid) , Copoly (styrene-maleic anhydride), copoly (styrene-acrylonitrile), copoly (styrene-butadiene), poly (vinylacetal) s (eg, poly (vinylformal) and poly (vinylbutyral)), poly (ester) Kind, poly ( Urethane), phenoxy resin, poly (vinylidene chloride), poly (epoxides),
Poly (carbonate) s, poly (vinyl acetate),
There are cellulose esters and poly (amides). It may be hydrophilic or non-hydrophilic. In order to protect the surface of the light-sensitive material and prevent abrasion, a non-light-sensitive layer may be provided outside the light-sensitive layer. The binder used for these non-photosensitive layers may be the same as or different from the binder used for the photosensitive layers.

In the present invention, in order to increase the speed of thermal development, the amount of binder in the photosensitive layer is 1.5 to 10 g / m ^2.
It is preferred that More preferably, 1.7 to 8 g
/ M ² .

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 30% based on all binders on the emulsion layer side.

The photothermographic material of the present invention, which forms a photographic image by heat development, comprises a reducible silver source (organic silver salt), a photosensitive silver halide, a reducing agent and, if necessary, silver. It is preferable that the photothermographic material contains a color toning agent which suppresses the color tone of the present invention in a state of being usually dispersed in an (organic) binder matrix. Although the photothermographic material of the present invention is stable at room temperature, it has a high temperature after exposure (for example, 80 to 140).
(° C.). 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. In order to control the amount or wavelength distribution of light passing through the photosensitive layer, a filter dye layer may be formed on the same side as the photosensitive layer and / or an antihalation dye layer, a so-called backing layer, may be formed on the opposite side.

These non-photosensitive layers preferably contain the binder or matting agent described above, and may further contain a slip agent such as a polysiloxane compound, wax or liquid paraffin.

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

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

When a mercapto compound is used in the present invention, it may be of any structure,
-S-S-Ar (M is a hydrogen atom or an alkali metal atom, and Ar is a heteroaromatic ring having one or more nitrogen, sulfur, oxygen, selenium or tellurium atoms) is preferable. . Preferably, benzimidazole, naphthimidazole, benzothiazole, naphthothiazole, benzoxazole, naphthoxazole, benzoselenazole, benzotellazole, imidazole, oxazole, pyrazole, triazole, thiadiazole, tetrazole, triazine,
Pyrimidine, pyridazine, pyrazine, pyridine, purine, quinoline or quinazolinone.

The heteroaromatic ring includes, for example, halogen (for example, atoms such as Br and Cl), hydroxy, amino, carboxy, and alkyl (for example, one or more carbon atoms, preferably 1 to 4 carbon atoms). ) And alkoxy (e.g., those having one or more carbon atoms, preferably 1 to 4 carbon atoms).

Examples of the heteroaromatic ring having a mercapto group include 2-mercaptobenzimidazole, 2-mercaptobenzoxazole, 2-mercaptobenzothiazole, 2-mercapto-5-methylbenzothiazole,
3-mercapto-1,2,4-triazole, 2-mercaptoquinoline, 8-mercaptopurine, 2,3,5
6-tetrachloro-4-pyridinethiol, 4-hydroxy-2-mercaptopyrimidine, 2-mercapto-4
-Phenyloxazole and the like, but are not limited thereto.

The photothermographic material of the present invention may contain an antifoggant. As the antifoggant, for example, antifoggants such as those disclosed in U.S. Pat. Nos. 4,546,075 and 4,452,885 and JP-A-59-57234 are preferable.

Particularly preferred antifoggants are compounds such as those disclosed in US Pat. Nos. 3,874,946 and 4,756,999, —C (X ₁ ) (X ₂ )
(X ₃ ) (where X ₁ and X ₂ are halogen and X ₃ is hydrogen or halogen) and is a heterocyclic compound having one or more substituents. Examples of suitable antifoggants include paragraphs [0030] to [00] of JP-A-9-288328.
36] are preferably used. Further, examples of another preferred antifoggant include JP-A-9-90550, paragraphs [0062] to [00].
63]. Still other suitable antifoggants are disclosed in U.S. Pat. Nos. 5,028,523 and British Patent Applications 9221383.4, 930.
Nos. 0147.7 and 93111790.1.

The photothermographic materials of the present invention include, for example, JP-A-63-159814, JP-A-60-140335, JP-A-63-231437, JP-A-63-259651 and JP-A-6-259551.
3-304242, 63-15245, U.S. Pat. Nos. 4,639,414, 4,740,455, 4,741,966, 4,751,175, and 4,835. No. 096 can be used.

Useful sensitizing dyes for use in the present invention include, for example, Research Disclosure Item
Section 17643 IV-A (p. 23, December 1978),
Item 1831X (August 1978, p. 437)
Or cited in the literature cited. In particular, a sensitizing dye having a spectral sensitivity suitable for the spectral characteristics of various scanner light sources can be advantageously selected. For example, JP-A-9-34078, JP-A-9-54409, and JP-A-9-80
No. 679 is preferably used.

The various additives may be added to any of the photosensitive layer, the non-photosensitive layer, and other layers. In the photothermographic material of the present invention, for example, a surfactant, an antioxidant,
Stabilizers, plasticizers, ultraviolet absorbers, coating aids, and the like may be used. These additives and the other additives mentioned above are Research Disclosure Item 1
Compounds described in No. 7029 (pp. 9-15, June 1978) can be preferably used.

The support used in the present invention may be a plastic film (for example, polyethylene terephthalate, polycarbonate, or the like) in order to prevent deformation of the image after development processing.
Polyimide, nylon, cellulose triacetate, polyethylene naphthalate) are preferred.

Among them, a preferred support is a support made of polyethylene terephthalate (hereinafter abbreviated as PET), polyethylene naphthalate (PEN), and a plastic (hereinafter abbreviated as SPS) containing a styrene polymer having a syndiotactic structure. Can be The thickness of the support is about 50 to 300 μm, preferably 70 to 250 μm.
μm.

The plastic support may be heat-treated.
The heat treatment of the support means that after the support is formed into a film and before the photosensitive layer is applied, the temperature of the support is higher than the glass transition point by 3 °.
The heating is performed at a temperature higher than 0 ° C., preferably at a temperature higher than 50 ° C. Next, the plastic used will be described.

PET is composed of polyethylene terephthalate as the polyester component. In addition to polyethylene terephthalate, terephthalic acid, naphthalene-2,6-dicarboxylic acid, isophthalic acid, butylene dicarboxylic acid, and 5-sodium sulfo acid are used as acid components. A polyester containing a modified polyester component of isophthalic acid, 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.

SPS is polystyrene having steric regularity unlike ordinary polystyrene (atactic polystyrene). The regular stereoregular structure part of SPS is called a racemo chain, and it is preferable that there are more regular parts such as two, three, five or more. In the present invention, the racemo chain is 2 It is preferably 85% or more in the chain, 75% or more in the three chains, 50% or more in the five chains, and 30% or more in the further chains. The polymerization of SPS can be carried out according to the method described in JP-A-3-131843.

Known methods can be used for the film forming method and the undercoating manufacturing method of the support.
No. 50094, paragraphs [0030] to [0070].

In the present invention, a conductive compound such as a metal oxide and / or a conductive polymer can be included in the constituent layer in order to improve the chargeability. These may be contained in any layer, but are preferably contained in an undercoat layer, a backing layer, a layer between the photosensitive layer and the undercoat, and the like.
In the present invention, the conductive compounds described in U.S. Pat. No. 5,244,773, columns 14 to 20, are preferably used.

[0086]

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 "Dye A" Dyes of Exemplified Compounds A-4 and A-8 were weighed at 5 g each and dissolved in a solvent consisting of 50 ml of tricresyl phosphate and 100 ml of ethyl acetate.
By emulsifying and dispersing in 1 l of pure water and further reducing the pressure,
The ethyl acetate was evaporated.

"Dye B" The dye of Exemplified Compound A-30 was
After weighing 0 g and dissolving in a solvent consisting of 50 ml of tricresyl phosphate and 100 ml of ethyl acetate, 30 g
Ethyl acetate was evaporated by emulsifying and dispersing in 0 ml of pure water and further reducing the pressure.

"Dye C" surfactant (TRITON X
-200: manufactured by Union Carbide Co.) 2.57 g of water 8
After dissolving in 5.43 g, 12 g of Exemplified Compound B-3 was added, and the mixture was preliminarily dispersed by ultrasonic waves, then put in a sand mill, and ground with zirconia oxide beads (0.5 mm in diameter) for 24 hours.

"Dye D" surfactant (TRITON X
-200: manufactured by Union Carbide Co.) 2.57 g of water 8
After dissolving in 5.43 g, 12 g of Exemplified Compound B-18 was added.
In addition, the mixture was pre-dispersed by ultrasonic waves, then put into a sand mill, and pulverized in zirconia oxide with beads (0.5 mm diameter) for 24 hours.

(Preparation of Silver Halide Emulsion A) 900 m of water
9. 30 g of inert gelatin and potassium bromide in 1 l.
_{5g, HO- (CH 2) 3} -S- (CH 2) 2 -S- (CH
₂ ) 10 ml of a 0.5% aqueous solution of _3- OH was added and stirred in a container kept at 72 ° C. while stirring a 0.88 M silver nitrate aqueous solution 30
ml and 0.075% of _{HO- (CH 2) 3 -S- (} C
_{H 2) 2 -S- (CH 2} ) 3 aqueous halide solution 0.88M consisting of potassium bromide / potassium iodide (96/4 mole ratio) containing -OH 30 ml and [Ir (NO) C
l _5] a 1 × 10 ^-6 mol and 1 × 10 ^-4 mol per mol of silver rhodium chloride salt per mole of silver salt, PAG7.
While maintaining at 7, the addition was performed by the controlled double jet method. Then, 4-hydroxy-6-methyl-1,3,3
3a, 7-Tetrazaindene was added, the pH was adjusted to 5 with sodium hydroxide, and the average diameter was 2 μm / thickness 0.12.
Tabular silver iodobromide grains of 5 μm were obtained. This emulsion was subjected to coagulation sedimentation using a gelatin coagulant, and after desalting, 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 A. Further, chemical sensitization was performed with chloroauric acid and inorganic sulfur.

(Preparation of sodium behenate solution) 945
32.4 g of behenic acid and 9.9 of arachidic acid in ml of pure water
g and stearic acid 5.6 g were dissolved at 90 ° C. Next, while stirring at a high speed, a 1.5 M aqueous sodium hydroxide solution 9 was added.
8 ml was added. Next, after adding 0.93 ml of concentrated nitric acid, the mixture was cooled to 55 ° C. and stirred for 30 minutes to obtain a sodium behenate solution.

(Preparation of Preform Emulsion of Silver Behenate and Silver Halide A) 15.1 g of the silver halide emulsion A was added to the above sodium behenate solution, and after adjusting the pH to 8.1 with a sodium hydroxide solution, 1N silver nitrate solution 1
47 ml was added over 7 minutes, the mixture was further stirred for 20 minutes, and water-soluble salts were removed by ultrafiltration. The resulting silver behenate was grains having an average grain size of 0.8 μm and a monodispersity of 8%. After the floc of the dispersion has formed, the water is removed and an additional 6
After washing with water and removing water several times, it was dried.

(Preparation of Photosensitive Emulsion) The dyes shown in Table 1 were added to the resulting preform emulsion, and 544 g of a solution of polyvinyl butyral (average molecular weight: 3000) in methyl ethyl ketone (17 wt%) and 107 g of toluene were gradually added and mixed. And then dispersed at 4000 psi.

The following layers were sequentially formed on the support,
A sample was prepared. The drying was performed at 60 ° C. for 15 minutes.

Back side coating: A liquid having the following composition was applied.

Cellulose acetate (10% methyl ethyl ketone solution) 15 ml / m ² dye-b 7 mg / m ² dye-c 7 mg / m ² Matting agent (monodispersity 15% average particle size 10 μm monodisperse silica) 30 mg / m ² C _{9 H 17 -C 6 H 4 -SO} 3 Na 10mg / m 2

[0098]

Embedded image

Photosensitive layer surface side coating Photosensitive layer 1: A solution having the following composition was coated and the silver amount was 2.1 g / m ^2.
It was applied on a PEN having a thickness of 175 μm and having a thickness of 175 μm, which had been subjected to corona discharge on both sides and had a concentration of 0.15.

Preform emulsion 240 g Sensitizing dye-1 (0.1% methanol solution) 1.7 ml Pyridinium hydrobromide perbromide (6% methanol solution) 3 ml Calcium bromide (0.1% methanol solution) 1.7 ml Antifoggant-2 (10% methanol solution) 1.2 ml 2- (4-chlorobenzoyl) benzoic acid (12% methanol solution) 9.2 ml 2-mercaptobenzimidazole (1% methanol solution) 11 ml tribromomethylsulfoquinoline (5% methanol solution) 17 ml C-4 (20% methanol solution) 29.5 ml

[0101]

Embedded image

Surface protective layer: A solution having the following composition was applied on the photosensitive layer.

Acetone 35 ml / m ² Methyl ethyl ketone 17 ml / m ² Cellulose acetate 2.3 g / m ² Methanol 7 ml / m ² Phthalazine 250 mg / m ² 4-Methylphthalic acid 180 mg / m ² Tetrachlorophthalic acid 150 mg / m ² Tetrachlorophthale Acid anhydride 170 mg / m ² Matting agent (monodispersity 10% average particle size 4 μm monodisperse silica) 70 mg / m ² C ₉ H ₁₇ -C ₆ H ₄ -SO ₃ Na 10 mg / m ² << Exposure and development treatment >> The photothermographic material prepared above was exposed with an imager having a semiconductor laser of 810 nm. Thereafter, heat development was performed at 110 ° C. for 15 seconds using an automatic developing machine having a heat drum. After the heat treatment, the resultant was gradually cooled to 90 ° C. for 2 minutes under tension, and then rapidly cooled to room temperature.

<< Evaluation after Heat Treatment >> The photothermographic material prepared above was divided into two parts, and one of them was put into a thermo machine at 90 ° C. and 80% for one day, and the color tone was observed.

A: Blue B: Slightly yellowish blue C: Slightly yellowish blue D: Yellowish blue E: Yellowish blue Those that do not reach B endure practical use Absent.

<< Evaluation of Silver Tone After Thermal Development >> The silver tone of the exposed portion of each sample was visually evaluated.

A: Cool black B: Slightly yellowish black C: Slightly yellowish black D: Yellow black E: Brownish Those that do not reach B are not practical.

<< Measurement of Scratch >> The photothermographic material prepared as described above was subjected to a heat development treatment at 110 ° C. for 15 seconds by using an automatic developing machine having 300 heat drums.

The number of sheets at which scratching starts to occur was evaluated according to the following evaluation criteria.

A: no abrasion B: abrasion occurred on 291 to 300 sheets C: abrasion occurred on 251 to 290 sheets D: abrasion occurred on 151 to 250 sheets E: abrasion occurred on 150 or less sheets The evaluation results are shown in Table 1. .

[0111]

[Table 1]

From Table 1, it can be seen that the blackness after the heat treatment and after the development was remarkably improved as compared with the comparison, and the occurrence of scratches was also remarkably suppressed.

[0113]

According to the present invention, it is possible to provide a high-sensitivity photothermographic material in which the occurrence of abrasion caused by the pressing of the drum during the heat development processing is suppressed and the color tone of the image is pure black.

Claims (3)

[Claims] 1. A photothermographic material having a photosensitive layer containing an organic silver salt, an antifoggant and photosensitive silver halide grains on at least one surface of a support, wherein the photosensitive layer or another layer is used. And a dye having a maximum absorption wavelength of 520 to 580 nm. 2. The photothermographic material according to claim 1, wherein a dye having a maximum absorption wavelength of 520 to 580 nm is dispersed and contained in a high boiling point solvent. 3. A dye having a maximum absorption wavelength of 520 to 580 nm, which is dispersed and contained in a solid.
2. The photothermographic material according to item 1.