JP2002268174A - Heat developable photosensitive material and processing method for the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a photosensitive material free of the dropping of dust in heat development and the generation of insufficient exposure in the exposure of a PS plate, excellent in dot reproducibility and having high contrast and high Dmax. SOLUTION: (1) In a heat developable recording material having an image recording layer containing the silver salt of an organic acid, silver halide, a binder and a reducing agent on the base, an image record protecting layer is disposed on the image recording layer and a cellulose ester having 4-20 mass% hydroxyl content is contained as part of a binder in the image recording layer and/or the image record protecting layer. (2) The cellulose ester is contained in the image recording layer by 5-50 mass% of the total mass of the binder in the image recording layer. (3) The cellulose ester is contained in the image record protecting layer by 5-50 mass% of the total mass of the binder in the image record protecting layer.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a photothermographic material and a heat development method thereof, and more particularly to an improvement in a binder for an image recording layer and a protective layer of the photothermographic material.

[0002]

2. Description of the Related Art Conventionally, in the fields of printing plate making and medical diagnosis,
Waste liquids associated with wet processing of image forming materials have become a problem in terms of workability, and in recent years, there has been a strong demand for reduction of processing waste liquids from the viewpoint of environmental conservation and space saving. on the other hand,
There is a demand for conversion of image information processing to digitalization. Therefore, there is a need for a technique capable of performing efficient exposure with a laser imagesetter or laser imager and forming a high-resolution, clear black image without a wet process.

As a technique for obtaining a photographic image without wet processing, for example, US Pat. No. 3,152,904, US Pat.
487,075 and D.C. Morgan
"Dry Silver Photographic Materials (Dry Silver
r Photographic Materials) "
(Handbook of Imaging Mate
reals, Marcel Dekker, Inc.
48, 1991), there is known a photothermographic material in which a support is provided with a layer containing an organic silver salt, photosensitive silver halide particles, a reducing agent and a binder. .

This photothermographic material forms a photographic image by a heat development process, and includes a reducible silver source (organic silver salt),
A photosensitive silver halide, a reducing agent and, if necessary, a color tone agent for suppressing the color tone of silver are usually contained in a dispersed state in an (organic) binder matrix. Such a photothermographic material is stable at room temperature, but is heated to a high temperature (for example, 80 ° C. to 140 ° C.) after exposure, so that oxidation between an organic silver salt (functioning as an oxidizing agent) and a reducing agent is performed. Generates silver through a reduction reaction. This oxidation-reduction reaction is accelerated by the catalytic action of the latent image formed 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 to form an image. This reaction process proceeds without supplying a processing liquid such as water from the outside.

[0005] Such a photothermographic material has been used as a microphotographic light-sensitive material or a radiographic light-sensitive material.
It is only partially used as a photosensitive material for printing. This is because the obtained image has a low Dmax and a low gradation, so that the image quality of the photosensitive material for printing is extremely poor.

On the other hand, in recent years, with the development of lasers and light-emitting diodes, there has been a strong demand for the development of a photosensitive material having scanner suitability having an oscillation wavelength of 600 to 800 nm, high sensitivity, high Dmax, and high contrast. Demands for simple processing and dry processing are also increasing.

As a technique to meet such a demand, US Pat. No. 5,464,738 and US Pat.
No. 695 discloses a photothermographic material containing an organic silver salt, silver halide, hindered phenols, and certain hydrazine derivatives. However, when these hydrazine derivatives are used, a sufficiently satisfactory Dma
x or ultra-high contrast cannot be obtained, and there is a problem that image quality deteriorates due to occurrence of black spots.

Hydrazine derivatives having improved black pot are disclosed in JP-A-9-292571, JP-A-9-304870 and JP-A-9-294870.
No. 304871, No. 9-304872, No. 10-31
No. 282, etc., and a hydrazine derivative having further improved image reproducibility are described in JP-A-10-62898. However, it has not yet satisfied the highest attainable density, ultra-high contrast property, and small-dot reproducibility.

Conventionally, as a binder for a photothermographic material, a polymer latex having a glass transition temperature (Tg) of -30.degree.
A polyvinyl butyral resin having a hydroxyl group content of 0.5 to 3.0 ° C. is used in the image recording protective layer.
For example, a cellulose ester of 20% by mass or a polymer latex having a Tg of 20 ° C to 70 ° C is used. In order to prevent sticking of the photothermographic material and improve transportability, a matting agent is used to make the surface of the photosensitive material uneven.

[0010] However, the conventional binder has poor adhesion to the matting agent, and when it is subjected to ultra-rapid processing, powder drop occurs, causing burning blur during PS plate baking, resulting in poor dot reproducibility. Therefore, there is a demand for the development of a technology that solves these problems.

[0011]

DISCLOSURE OF THE INVENTION The present invention has excellent adhesiveness between a matting agent and a layer holding the matting agent, prevents the occurrence of powder dropping off during heat development processing, and reduces the likelihood of blurring during PS plate baking. Dma with high contrast without generation and excellent small point reproducibility
It is an object to provide a photosensitive material having a high x.

[0012]

The constitution of the present invention for solving the above-mentioned problems is as follows.

(1) In a heat-developable recording material having an image recording layer containing an organic silver salt, a silver halide, a binder and a reducing agent on a support, an image recording protective layer is provided on the image recording layer. A photothermographic material, wherein the image recording layer and / or the image recording protective layer contains a cellulose ester having a hydroxyl group content of 4 to 20% by mass as a part of a binder.

(2) The image recording layer contains a cellulose ester having a hydroxyl group content of 4 to 20% by mass in a ratio of 5 to 50% by mass based on the total binder mass of the image recording layer. The photothermographic material according to (1).

(3) The image recording protective layer contains a cellulose ester having a hydroxyl group content of 4 to 20% by mass in a ratio of 5 to 50% by mass based on the total binder mass of the image recording protective layer. The photothermographic material according to the above (1), wherein

(4) The image recording layer contains a cellulose ester having a hydroxyl group content of 4 to 20% by mass of 10 to 70% by mass of the binder of the layer and the image recording protective layer has a hydroxyl group content of 4 to 20% by mass. The photothermographic material according to (1), wherein the photothermographic material contains 20% by mass of a cellulose ester in an amount of 10 to 70% by mass of the binder in the layer.

(5) The image recording protective layer contains a resin (A) having a hydroxyl group content of 0.5 to 3% by mass and a resin (B) having a hydroxyl group content of 4 to 20% by mass. The mass ratio of A) / resin (B) is 95/5 to 50/50.
The photothermographic material according to any one of the above (1) to (4), wherein

(6) The photothermographic material according to the above (1), wherein the image recording layer contains an acrylic resin.

(7) The method according to any one of (1) to (6) above, wherein an undercoat layer containing an acrylic resin and / or polyester is provided between the support and the image recording layer. Developed photosensitive material.

(8) The above-mentioned (1) to (1) to (1), wherein 50% by mass or more of the total binder of the image recording layer comprises a polymer latex, and 30% by mass or more of the solvent of the coating solution for the image recording layer is water. The photothermographic material according to any one of (5) and (4).

(9) The photothermographic material according to any one of the above (1) to (6), wherein the transport speed of the thermal developing machine is 22.
A method for processing a photothermographic material, wherein the photothermographic material is thermally developed at a speed of not less than 40 mm / sec.

[0022]

The organic silver salt contained in the image recording layer of the photothermographic material according to any one of claims 1 to 9, is a silver salt of an organic acid containing a reducible silver ion source and a silver salt of a heteroorganic acid, especially a long salt. Aliphatic carboxylic acids of the chain (10-30, preferably 15-25 carbon atoms) and nitrogen-containing heterocycles are preferred. Organic or inorganic silver salt complexes whose ligands have 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
issuer (hereinafter abbreviated as “RD”) 170
29 and 29996, and include the following. Salts of organic acids (eg, gallic acid, oxalic acid,
Salts of behenic acid, stearic acid, palmitic acid, lauric acid and the like); carboxyalkylthiourea salts of silver (for example,
1- (3-carboxypropyl) thiourea, 1- (3-
Aldehydes and hydroxy-substituted aromatic carboxylic acids (for example, aldehydes such as formaldehyde, acetaldehyde, butyraldehyde and salicylic acid, benzylic acid, 3,5-dihydroxybenzoic acid, 5) Silver complex of a polymer reaction product with a hydroxy-substituted acid such as 2,5-thiodisalicylic acid); silver salt or complex of a thione (for example, 3- (2-carboxyethyl) -4-hydroxymethyl-4-thiazoline) -2-thione and 3-carboxymethyl-4-methyl-4-thiazoline-2-thione); imidazole, pyrazole, urazole, 1,
Complexes or salts of silver with a nitrogen acid selected from 2,4-thiazole and 1H-tetrazole, 3-amino-5-benzylthio-1,2,4-triazole and benzotriazole; saccharin, 5-chlorosalicylaldoxime And silver salts of mercaptides. Preferred organic silver salts are silver behenate, silver arachidate and silver stearate, and one or more of these can be used in combination.

The organic silver salt can be obtained by mixing a water-soluble silver compound and a compound which forms a complex with silver. The mixing includes a forward mixing method, a reverse mixing method, a simultaneous mixing method, and a method disclosed in
A controlled double jet method or the like described in Japanese Patent No. 127643 is preferably used. For example, an organic acid alkali metal salt soap (eg, sodium behenate, sodium arachidate, etc.) is prepared by adding an alkali metal salt (eg, sodium hydroxide, potassium hydroxide, etc.) to an organic acid, and then controlled double jet. According to the method, the soap and silver nitrate are added to produce crystals of an organic silver salt. At that time, silver halide grains may be mixed.

The silver halide contained in the image recording layer functions as an optical sensor. In the present invention, the average grain size of the silver halide is preferably smaller in order to suppress white turbidity after image formation and to obtain good image quality, and the average grain size is preferably 0.1 μm or less, more preferably 0.1 μm or less. 01-0.1 μm, especially 0.02-
0.08 μm is preferred. The particle size here means
When the silver halide grains are cubic or octahedral so-called normal crystals, they refer to the lengths of the edges of the silver halide grains. 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. The silver halide grains are preferably monodispersed. The term “monodisperse” as used herein means that the variation coefficient of the particle size distribution obtained by the following equation is 40% or less. The coefficient of variation is more preferably 30% or less, particularly preferably 0.1 to 20%.

Coefficient of variation (%) in grain size distribution = (standard deviation of grain size / average grain size) × 100 In the present invention, the silver halide contained in the image recording layer has an average grain size of 0.1 μm or less. And monodisperse particles are preferable, whereby the granularity of the obtained image is also improved.

The shape of the silver halide grains is not particularly limited, but the ratio occupied by the Miller index (100) plane is preferably high, and this ratio is 50% or more, and more preferably 70%.
%, Particularly preferably 80% or more. The ratio of the (100) plane of the Miller index is determined by the T.V. method using the adsorption dependency between the (111) plane and the (100) plane in the adsorption of the sensitizing dye. Tani; Imaging Sci. , 29,
165 (1985).

Another preferred form of silver halide grains is tabular grains. As used herein, the term “tabular grain” refers to an aspect ratio where the square root of the projected area of the silver halide grain is r μm and the thickness in the vertical direction is h μm = r / h.
Means three or more particles. Among them, the aspect ratio is preferably 3 or more and 50 or less. The particle size is 0.1μ
m or less, more preferably 0.01 to 0.0
8 μm is preferred. Such tabular grains are disclosed in U.S. Patent Nos. 5,264,337 and 5,314,798.
No. 5,320,958, and the like, and intended tabular grains can be easily obtained. When tabular grains are used in the present invention, the sharpness of an image is further improved.

The halogen composition of the silver halide is not particularly limited, and may be silver chloride, silver chlorobromide, silver chloroiodobromide, silver bromide,
Any of silver iodobromide and silver iodide may be used. Silver halide emulsions containing silver halide grains used in the present invention are described in P.I. Chimie et P by Glafkides
hysique Photographique (Pa
ul Montel, 1967); F. Du
Photographic Emulsi by fin
on Chemistry (The Focal Pr
ess, 1966); L. Zelikman
Making and Coating by et al
Photographic Emulsion (The
Focal Press, 1964) and the like.

The silver halide grains used in the present invention may contain ions or complex ions of metals belonging to Groups 6 to 10 of the Periodic Table of the Elements for the purpose of improving illuminance failure and adjusting gradation. preferable. As the above metals,
W, Fe, Co, Ni, Cu, Ru, Rh, Pd, R
e, Os, Ir, Pt, and Au are preferred.

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

In the present invention, the silver halide grains are preferably chemically sensitized. Preferred chemical sensitization methods include sulfur sensitization, selenium sensitization, tellurium sensitization, gold compounds and platinum, palladium, which are well known in the art.
A noble metal sensitization method such as an iridium compound or a reduction sensitization method can be appropriately selected and used. A method for forming silver halide is well known in the art, and for example, a method described in Research Disclosure 17029 (June 1978), U.S. Pat. No. 3,700,458 or the like can be used. it can.

In the present invention, in order to prevent devitrification of the obtained image, the total amount of silver halide grains and organic silver salts is converted into 0.3 per 0.3 m ^{2 of the} photothermographic material.
To 2.2 g, preferably 0.5 g to 1.5 g
Is more preferred. In addition, a high-contrast image can be obtained by setting this range. The amount of silver halide relative to the total amount of silver is preferably 50% or less by mass, more preferably 2% or less.
5% or less, more preferably 0.1 to 15%.

In the present invention, silver halide grains can be spectrally sensitized. Examples of the spectral sensitizing dye include, for example, JP-A-63-159814 and JP-A-60-14033.
No. 5, 63-231437, 63-259651
Nos. 63-304242 and 63-15245, and U.S. Pat. Nos. 4,639,414 and 4,
The sensitizing dyes described in each specification such as 740,455, 4,741,966, 4,751,175, and 4,835,096 can be used. . Useful sensitizing dyes used in the present invention include, for example, Research Disclosure (hereinafter abbreviated as “RD”).
Section 17643 IV-A (p. 23, December 1978),
No. 1831X (August 1978, p. 437). Further, a spectral sensitizing dye having a spectral sensitivity suitable for the spectral characteristics of various scanner light sources can be selected.
No. 34078, No. 9-54409, No. 9-80679
The sensitizing dye described in No. 1 is preferably used.

The image recording layer of the photothermographic material of the present invention contains a reducing agent for an organic silver salt. Examples of suitable reducing agents are described in U.S. Patent Nos. 3,770,448 and 3,773.
No. 512, No. 3,593,863, and RD170
29 and RD29963, and include the following.

Aminohydroxycycloalkenone compounds (eg, 2-hydroxy-3-piperidino-2-cyclohexenone); aminoreductones esters (eg, piperidinohexose reductone monoacetate) as precursors of reducing agents N-hydroxyurea derivatives (for example, Np-methylphenyl-N-hydroxyurea); hydrazones of aldehydes or ketones (for example, anthracene aldehyde phenylhydrazone); phosphoramidophenols; phosphoramidoanilines; Hydroxybenzenes such as hydroquinone, t-butyl-hydroquinone, isopropylhydroquinone and (2,5-dihydroxy-
Phenyl) methylsulfone); sulfhydroxamic acids (e.g., benzenesulfhydroxamic acid); sulfonamidoanilines (e.g., 4- (N-methanesulfonamido) aniline); 2-tetrazolylthiohydroquinones (e.g., 2 -Methyl-5- (1-phenyl-5-
Tetrazolylthio) hydroquinone); tetrahydroquinoxalines (eg, 1,2,3,4-tetrahydroquinoxaline); amide oximes; azines; combinations of aliphatic carboxylic acid arylhydrazides and ascorbic acid; polyhydroxybenzene and hydroxylamine Reductone and / or hydrazine; hydroxanoic acids; combinations of azines and sulfonamidophenols; α-cyanophenylacetic acid derivatives; combinations of bis-β-naphthol and 1,3-dihydroxybenzene derivatives; 5-pyrazolones; Sulfonamide phenol reducing agent; 2-phenylindane-1,
3-dione and the like; chroman; 1,4-dihydropyridines (eg, 2,6-dimethoxy-3,5-dicarbethoxy-1,4-dihydropyridine); bisphenols (eg, bis (2-hydroxy-3- t-butyl-5
-Methylphenyl) methane, bis (6-hydroxy-m
-Tri) mesitol, 2,2-bis (4-hydroxy-3-methylphenyl) propane,
4,4-ethylidene-bis (2-t-butyl-6-methylphenol)), ultraviolet-sensitive ascorbic acid derivatives; hindered phenols; 3-pyrazolidones. Among them, particularly preferred reducing agents are hindered phenols. Examples of hindered phenols include compounds represented by the following general formula (1).

[0037]

Embedded image

In the formula, R is a hydrogen atom or a group having 1 carbon atom.
To 10 alkyl groups (for example, -C _FourH₉, 2,4,4-
Trimethylpentyl), and R ′ and R ″ are each
An alkyl group having 1 to 5 carbon atoms (e.g., methyl, ethyl
Tert-butyl).

The cellulose ester having a hydroxyl group content of 4 to 20% by mass contained in the image recording layer and / or the image recording protective layer of the photothermographic material according to claims 1 to 4 will be described. Known cellulose esters as the cellulose ester, for example, cellulose nitrate, cellulose acetate,
Cellulose acetate topionate, cellulose acetate butyrate, cellulose propionate, cellulose butyrate, and the like can be used, but cellulose acetate butyrate and cellulose acetate propionate are preferred. A cellulose ester having a hydroxyl group content of 4 to 20% by mass has excellent compatibility even when used in combination with another type of resin, and can improve the adhesion between the respective layers. The acetyl group content is preferably 0.2
５０50 mass%, butylyl group content is preferably 5-6
0 mass%, the content of propionyl group is preferably 5-6.
0% by mass.

When the content of the hydroxyl group is less than 4% by mass, the effect of improving the adhesiveness is not sufficient, and when the content of the hydroxyl group is more than 20% by mass, the charging characteristics deteriorate,
It is not preferable because fatty acid bleeds out on the surface of the coating film after thermal development. The content of the hydroxyl group in the cellulose ester contained in the image recording layer according to any one of claims 1 to 4 is preferably 4 to 12% by mass, and more preferably 4 to 8% by mass.

The cellulose ester having a hydroxyl group content of 4 to 20% by mass, wherein the image recording layer and / or the image recording protective layer of the photothermographic material according to any one of claims 1 to 4, is a part of a binder. Is preferably contained in a ratio of 5 to 50% by mass, more preferably 10 to 40% by mass, and still more preferably 15 to 50% by mass with respect to the total mass of the binder.
35% by mass. In addition, the cellulose ester having a hydroxyl group content of 4 to 20% by mass contained in the image recording protective layer is 5% based on the total binder mass of the image recording protective layer.
It is preferably contained at a ratio of ５０50% by mass, more preferably 10 to 40% by mass, and still more preferably 15 to 35% by mass.

Further, the image recording layer and the image recording protective layer each contain a cellulose ester having a hydroxyl group content of 4 to 20% by mass in a ratio of 10 to 70% by mass with respect to the binder mass of these layers. Is preferred,
More preferably, 15 to 65% by mass, still more preferably 2 to 65% by mass.
0 to 60% by mass.

The photothermographic material according to any one of claims 1 to 4, further comprises a cellulose ester having a hydroxyl group content of 4 to 20% by mass as a part of the binder contained in the image recording layer and / or the image recording protective layer. As the binder other than the cellulose ester, a polymer compound (resin) known as a binder for the image recording layer and the image recording protective layer of the photothermographic material can be used. Preferred binders include the following hydrophobic resins and hydrophilic resins, which can be used depending on their suitability.

The hydrophobic resin has advantages such as reducing fog after thermal development. Preferred hydrophobic resins include polyvinyl butyral, cellulose acetate, cellulose acetate butyrate, polyester, polycarbonate, acrylic resin, polyurethane, and the like. And vinyl chloride resin. Among them, polyvinyl butyral, cellulose acetate, cellulose acetate butyrate,
Polyester and polyurethane are particularly preferably used.

As the hydrophilic resin, for example, acrylic resin, polyester, polyurethane, vinyl chloride resin, vinylidene chloride resin, rubber resin (for example, SBR resin or N
(BR resin), vinyl acetate resin, polyolefin, polyvinyl acetal and the like. The resin may be a homopolymer in which a single monomer is polymerized, or a copolymer in which two or more monomers are copolymerized, and may have a linear or branched structure. Further, the resins may be cross-linked.

The above resins are also commercially available, and the following can be used. As an acrylic resin, for example,
Sebian A-4635, 46583, 4601 (all manufactured by Daicel Chemical Industries, Ltd.), Nipol LX811,
814, 820, 821, 857 (all manufactured by Zeon Corporation) and the like. As the polyester, for example, FIN
ETEX ES650, 611, 679, 675, 52
5,801,850 (Dai Nippon Ink Chemical Co., Ltd.)
WDsize WHS (manufactured by Eastman Chemical). As the polyurethane, for example, HYDRAN
AP10, 20, 30, 40, 101H, HYDRA
Examples of vinylidene chloride resins such as NHW301, 310, and 350 (all manufactured by Dainippon Ink and Chemicals, Inc.) include L502, L513, L123c, L106c, and L106.
Examples of vinyl chloride resins such as 111 and L114 (all manufactured by Asahi Kasei Corporation) include G351 and G576.
(Nippon Zeon Co., Ltd.) and the like, for example, Chemipearl S-120, S-300, S
A-100, A-100, V-100, V-200, V
-300 (all manufactured by Mitsui Petrochemical Co., Ltd.). These resins may be used alone or in a combination of two or more.

These resins are represented by —SO ₃ M, —O
_{SO 3 M, -PO (OM 1} ) 2 and -OPO (OM _{1) 2}
(However, M represents a hydrogen atom or an alkali metal atom such as Na, K, and Li, and M ₁ represents a hydrogen atom, an alkali metal atom such as Na, K, and Li or an alkyl group) It is preferable to have a polar group,
Among them _{-SO 3 Na, -SO 3 K,} -OSO 3 Na, -O
It preferably has SO ₃ K. The molecular weight of the resin is usually 5,000 to 100,000, preferably 10,000 to 50,000 in terms of weight average molecular weight. Among these, the resin used as the binder for the image recording layer is preferably an acrylic resin, polyvinyl acetal, a rubber-based resin, polyurethane, or polyester, and more preferably a styrene-butadiene resin, polyurethane, or polyester. The glass transition temperature (Tg) of the binder (of the image recording layer) is preferably from 45 to 150.
° C, more preferably 60 ° C to 120 ° C. The binder used for the image recording protective layer and the back coat layer is preferably a cellulose ester, an acrylic resin, or a polyurethane. The glass transition temperature (Tg) of the binder in the layer is preferably from 75 to 200C, more preferably from 100 to 160C.

The above-mentioned polymer compound is also used as a binder for a back coat layer, an undercoat layer and the like other than the image recording layer and the image recording protective layer of the present invention.

In a preferred embodiment of the photothermographic material according to claims 1 to 4, the image recording protective layer comprises a resin (A) having a hydroxyl group content of 0.5 to 3% by mass and a hydroxyl group content of 4%. -20% by mass of resin (B), and the mass ratio of resin (A) / resin (B) is 95/5 to 50/5.
0 is mentioned. According to this embodiment, it is possible to obtain an effect that the value of the surface resistivity can be maintained at a favorable level while maintaining good adhesion.

The resin (A) preferably has a hydroxyl group content of 0.7 to 2.5% by mass, more preferably 1.
0 to 2.0% by mass. The mass ratio (A) / (B) of the resin (A) and the resin (B) contained in the image recording protective layer is preferably from 90/10 to 60/40, more preferably from 85/15 to 65/35. is there.

The hydroxyl group content is 0.5 to 3% by mass
As the resin (A), a cellulose ester having a hydroxyl group content with a saponification degree in the above range can be used. As the cellulose ester, cellulose acetate butyrate and cellulose acetate propionate are preferably used. Further, polyvinyl acetate having a hydroxyl group of the above content, polyvinyl acetal,
Hydroxyethyl (meth) acrylate;

As the resin (B) having a hydroxyl group content of 4 to 20% by mass, a cellulose ester having a hydroxyl group content in a saponification degree within the above range can be used.
As the cellulose ester, cellulose acetate butyrate and cellulose acetate propionate are preferably used. Further, polyvinyl acetate, polyvinyl acetal, hydroxyethyl (meth) acrylate having a hydroxyl group having the above-mentioned content and the like can be mentioned.

The number average molecular weight (Mn) of the resins (A) and (B) is preferably in the range of 5,000 to 100,000, more preferably 10,000 to 80,000.

In the image recording layer of the photothermographic material according to any one of claims 1 to 5, 50% by mass or more of the total binder of the layer is composed of a polymer latex, and 30% by mass or more of the solvent of the image recording layer coating solution is 30% by mass or more. It is preferably formed by applying and drying a coating liquid which is water. The content of the polymer latex with respect to the total binder is more preferably 65% by mass or more, and further preferably 80% by mass or more. The polymer latex is obtained by dispersing a polymer in an aqueous dispersion medium, and the above-mentioned mass% is the mass% of the polymer. Further, it is more preferable that 45% by mass or more of the solvent is water, and it is further preferable that 60% by mass or more is water. According to this embodiment, the effects of improving the density unevenness, the maximum density, and the transportability of the image obtained by the heat development are further enhanced, and the production efficiency is high, and the environmental suitability is excellent.

Preferred specific examples of the polymer latex include the following.

[0056] _{PL-1 :-( MMA) 50 -} (EA) 45 -
(AA) ₅ - latex (Mw = 3 million _{in) PL-2 :-( 2EHA) 30} - (MMA) 50 - (St)
₁₅ - (MAA) ₅ - latex (Mw = 5 million _{in) PL-3 :-( BR) 50} - (St) 47 - (AA) 3 - latex (Mw = 1 million in) PL-4 :-( BR ) _40- (DVB) _10- (St) _45-
(MAA) ₅ - latex (Mw = 5 million _{in) PL-5 :-( VC) 70} - (MMA) 25 - (AA) 5 -
Latex (Mw = 1.5 million _{in) PL-6 :-( VDC) 60} - (MMA) 30 - (EA) 5
-(MAA) _5- Latex (Mw = 80,000) In the above, abbreviations represent structural units derived from the following monomers, and numerical values are% by mass.

MMA: methyl methacrylate, EA: ethyl acrylate, AA: acrylic acid, 2EHA: 2-
Ethylhexyl acrylate, St: styrene, MA
A: methacrylic acid, BR: butadiene, DVB: divinylbenzene, VC: vinyl chloride, VDC: vinylidene chloride.

Such a polymer is also commercially available, and the following can be used. For example, as the acrylic resin, Sebian A-4635, 46583, 46
01 (both manufactured by Daicel Chemical Industries, Ltd.), Nipol
LX811, 814, 820, 821, 857 (all manufactured by Nippon Zeon Co., Ltd.) and the like. As polyester resin,
FINITEX ES650, 611, 679, 67
5, 525, 801, 850 (all manufactured by Dainippon Ink and Chemicals, Inc.), WDsize WHS (manufactured by Eastman Chemical), and the like. As the polyurethane resin, HYDRAN
AP10, 20, 30, 40, 101H, HYDRA
Examples of vinylidene chloride resins such as N HW301, 310, and 350 (all manufactured by Dainippon Ink and Chemicals, Inc.) include L5
02, L513, L123c, L106c, L111,
Examples of vinyl chloride resins such as L114 (manufactured by Asahi Kasei Kogyo Co., Ltd.) include G351 and G576 (manufactured by Nippon Zeon Co., Ltd.). Examples of polyolefin resins include Chemipearl S-120, S-300, and SA-100. , A-10
0, V-100, V-200, and V-300 (all manufactured by Mitsui Petrochemical Co., Ltd.). In the present invention, the binder may be used alone these polymers,
Two or more types may be blended and used.

These resins are -SO ₃ M, -OS
_{O 3 M, -PO (OM 1} ) 2 and -OPO (OM _1)
2 (where M represents a hydrogen atom or an alkali metal atom such as Na, K, Li, etc., and M ₁ represents a hydrogen atom, Na, K, Li
And at least one polar group selected from the group consisting of an alkali metal atom and an alkyl group.

The number average molecular weight (Mn) of the polymer latex is preferably in the range of 5,000 to 1500,000, more preferably 10,000 to 100,000.

The photothermographic material according to claim 1 can contain an acrylic resin as a part of the binder in the image recording layer. The acrylic resin may be a homopolymer in which a single monomer is polymerized, or a copolymer in which two or more monomers are copolymerized. The copolymer may be a monomer unit other than acrylics. May be included. The resin may have a linear or branched structure, and the resin has a weight average molecular weight Mw of preferably from 1,000 to 1,
One million, more preferably 3000 to 500,000. When it is a copolymer, it may be a random copolymer or a block copolymer. Specific examples include polymethacrylate, polymethyl methacrylate, polyacrylate, polyalkyl methacrylate / acrylate copolymer, and polystyrene / polymethacrylate copolymer.

The content of the acrylic resin contained in the image recording layer is usually 1 to 5 with respect to the total binder mass of the image recording layer.
0 mass%, preferably 2 to 30 mass%, more preferably 3 to 10 mass%. When the content is within these ranges, a transparent coating film can be obtained even when the compatibility with the binder used in combination is poor, and the haze value can be kept small.

The photothermographic material according to claims 1 to 6 includes:
An undercoat layer containing an acrylic resin and / or polyester may be provided between the support and the image recording layer.
As the acrylic resin, a homopolymer such as methyl methacrylate, ethyl acrylate, acrylic acid, methacrylic acid, 2-ethylhexyl acrylate, or a copolymer obtained by copolymerizing two or more thereof, a copolymer of methacrylic acid and styrene, Copolymers of a monomer with butadiene, divinylbenzene, vinyl chloride, vinylidene chloride and the like can be mentioned.

Further, such resins are commercially available, and the following resins can be used. For example, as the acrylic resin, Sebian A-4635, 46583, 4601
(Daicel Chemical Industries, Ltd.), Nipol LX
811, 814, 820, 821, and 857 (all manufactured by Nippon Zeon Co., Ltd.).

As the polyester resin, FINITE
X ES650, 611, 679, 675, 525, 8
01, 850 (all manufactured by Dainippon Ink and Chemicals, Inc.), WD
Size WHS (manufactured by Eastman Chemical) or the like can be used. In the present invention, these binders may be used alone or as a blend of two or more.

The undercoat layer may contain a crosslinking agent for crosslinking and a surfactant for improving coating properties. As a crosslinking agent, an isocyanate group, a vinylsulfonyl group,
Alternatively, a crosslinking agent having an epoxy group is preferred, and a particularly preferred crosslinking agent is a polyfunctional crosslinking agent having two isocyanate groups, vinylsulfonyl groups, or two epoxy groups.

The concentration of the undercoat liquid is usually preferably 20% by mass or less, more preferably 15% by mass or less. The coating amount is preferably 1 dry mass per 1 m ^{2 of the} photothermographic material.
-20 g, more preferably 5-15 g.

The heat-developable recording material of the present invention preferably contains a high contrast agent. As a high contrast agent, a hydrazine derivative represented by the following general formula (H), a compound represented by the general formula (G), a quaternary onium compound represented by the general formula (P), a general formula (A) to ( The compound represented by D), a hydroxyamine, an alkanolamine, an ammonium phthalate compound, etc. are mentioned. First, the following general formula (H)
The hydrazine derivative represented by is described.

[0069]

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In the formula, A ₀ represents an aliphatic group, an aromatic group, a heterocyclic group or a -G ₀ -D ₀ group which may have a substituent, B ₀ represents a blocking group, and A ₁ and A ₂ is a hydrogen atom, or one is a hydrogen atom and the other is an acyl group,
Represents a sulfonyl group or an oxalyl group. Where G ₀
Is -CO-, -COCO-, -CS-, -C (=
NG ₁ D ₁ ) —, —SO—, —SO ₂ — or —P
(O) represents a (G ₁ D ₁ ) — group, wherein G ₁ is a mere bond;
O—, —S— or —N (D ₁ ) —, wherein D ₁ represents an aliphatic group, an aromatic group, a heterocyclic group or a hydrogen atom;
When multiple D ₁ are present in a molecule, they may be the same or different. D ₀ represents a hydrogen atom, an aliphatic group, an aromatic group, a heterocyclic group, an amino group, an alkoxy group, an aryloxy group, an alkylthio group, or an arylthio group. Preferred D ₀ includes a hydrogen atom, an alkyl group, an alkoxy group, an amino group and the like.

In the general formula (H), the aliphatic group represented by A ₀ preferably has 1 to 30 carbon atoms, and particularly preferably a linear, branched or cyclic alkyl group having 1 to 20 carbon atoms. For example, a methyl group, an ethyl group, a t-butyl group,
Octyl group, cyclohexyl group, benzyl group and the like. These are further suitable substituents (for example, aryl group,
Alkoxy, aryloxy, alkylthio, arylthio, sulfoxy, sulfonamido, sulfamoyl, acylamino, ureido, etc.).

In the general formula (H), the aromatic group represented by A ₀ is preferably a monocyclic or condensed-ring aryl group.
For example, a benzene ring or a naphthalene ring is mentioned, and A ₀
The heterocyclic group represented by is preferably a heterocyclic ring containing at least one hetero atom selected from nitrogen, sulfur, and oxygen atoms in a single ring or a condensed ring, for example, a pyrrolidine ring, an imidazole ring, a tetrahydrofuran ring, a morpholine ring Pyridine ring, pyrimidine ring, quinoline ring, thiazole ring, benzothiazole ring, thiophene ring, furan ring and the like. Aromatic group represented by A _0, heterocyclic group or -G ₀ -D ₀ group may have a substituent. A ₀
Are particularly preferably an aryl group, -G ₀ -D
₀ group and substituted alkyl group.

In the general formula (H), A ₀ preferably contains at least one diffusion-resistant group or silver halide-adsorbing group. As the diffusion-resistant group, a ballast group commonly used in immobile photographic additives such as couplers is preferable, and as the ballast group, a photographically inert alkyl group,
Examples thereof include an alkenyl group, an alkynyl group, an alkoxy group, a phenyl group, a phenoxy group, and an alkylphenoxy group. The total number of carbon atoms in the substituent is preferably 8 or more.

As the silver halide adsorbing group, thiourea,
Examples include a thiourethane group, a mercapto group, a thioether group, a thione group, a heterocyclic group, a thioamide heterocyclic group, a mercapto heterocyclic group, and an adsorption group described in JP-A-64-90439.

In the general formula (H), B ₀ represents a blocking group, preferably a -G ₀ -D ₀ group, and G ₀ represents-
CO- group, -COCO- group, -CS- group, -C (= NG
₁ D ₁₎ - group, -SO- group, -SO ₂ - group or -P
(O) represents a (G ₁ D ₁ ) — group. Preferred G ₀ is-
A CO— group and a —COCO— group, and G ₁ represents a simple bond, a —O— group, a —S— group, or a —N (D ₁ ) — group, and D ₁ represents an aliphatic group or an aromatic group. , A heterocyclic group or a hydrogen atom, and when a plurality of D ₁ are present in the molecule, they may be the same or different. D ₀ represents a hydrogen atom, an aliphatic group, an aromatic group, a heterocyclic group, an amino group, an alkoxy group, an aryloxy group, an alkylthio group, or an arylthio group, and preferred D ₀ is a hydrogen atom, an alkyl group, an alkoxy group, And an amino group. A ₁ , A ₂
Are both hydrogen atoms, or one is a hydrogen atom and the other is an acyl group (acetyl group, trifluoroacetyl group, benzoyl group, etc.), a sulfonyl group (methanesulfonyl group, toluenesulfonyl group, etc.), or an oxalyl group (ethoxalyl group, etc.) Represents

More preferred hydrazine derivatives are represented by the following general formulas (H-1), (H-2), (H-3) or (H
-4).

[0077]

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In the general formula (H-1), R ₁₁ , R ₁₂ and R ₁₃ each independently represent a substituted or unsubstituted aryl group or heterocyclic group. Specific examples of the aryl group include a phenyl group , P-tolyl group, naphthyl group and the like. Specific examples of the heterocyclic group include a triazole residue, an imidazole residue, a pyridine residue, a furan residue, and a thiophene residue. Also, R
₁₁ , R ₁₂ and R ₁₃ may be bonded via an arbitrary linking group. When R ₁₁ , R ₁₂ and R ₁₃ have a substituent, examples of the substituent include an alkyl group, an alkenyl group, an alkynyl group, an aryl group, a heterocyclic group, a quaternary heterocyclic group containing a nitrogen atom ( For example a pyridinio group),
A hydroxy group, an alkoxy group (including a group repeatedly containing an ethyleneoxy group or a propyleneoxy group unit),
Aryloxy group, acyloxy group, acyl group, alkoxycarbonyl group, aryloxycarbonyl group, carbamoyl group, urethane group, carboxyl group, imide group,
Amino group, carbonamido group, sulfonamido group, ureido group, thioureido group, sulfamoylamino group, semicarbazide group, thiosemicarbazide group, hydrazino group, quaternary ammonium group, (alkyl, aryl, or heterocyclic) thio group A mercapto group, an (alkyl or aryl) sulfonyl group, an (alkyl or aryl) sulfinyl group, a sulfo group, a sulfamoyl group, an acylsulfamoyl group, an (alkyl or aryl) sulfonyluureido group, an (alkyl or aryl) sulfonylcarbamoyl group, Examples include a halogen atom, a cyano group, a nitro group, and a phosphoric amide group. Preferably, all of R ₁₁ , R ₁₂ and R ₁₃ are substituted or unsubstituted phenyl groups, and more preferably, all of R ₁₁ , R ₁₂ and R ₁₃ are unsubstituted phenyl groups.

R ₁₄ represents a heterocyclic oxy group or a heterocyclic thio group. Specific examples of the heterocyclic oxy group include a pyridyloxy group, a pyrimidyloxy group, an indolyloxy group, a benzothiazolyloxy group, a benzimidazolyl group. An oxy group,
Examples include a furyloxy group, a thienyloxy group, a pyrazolyloxy group, and an imidazolyloxy group. Specific examples of the heterocyclic thio group include a pyridylthio group, a pyrimidylthio group, an indolylthio group, a benzothiazolylthio group, a benzimidazolylthio group, a furylthio group, a thienylthio group, a pyrazolylthio group, and an imidazolylthio group. R ₁₄ is preferably a pyridyloxy group or a thienyloxy group.

A ₁ and A ₂ are both a hydrogen atom, or one is a hydrogen atom and the other is an acyl group (acetyl, trifluoroacetyl, benzoyl, etc.), a sulfonyl group (methanesulfonyl, toluenesulfonyl, etc.), or an oxalyl group ( Ethoxalyl). Preferably, A ₁ and A ₂ are both hydrogen atoms.

In the general formula (H-2), R ₂₁ represents a substituted or unsubstituted alkyl group, aryl group or heterocyclic group. Specific examples of the alkyl group include a methyl group, an ethyl group and a tert-butyl group. Group, 2-octyl group, cyclohexyl group, benzyl group, diphenylmethyl group and the like. Specifically as the aryl group and the heterocyclic group,
The same as R ₁₁ , R ₁₂ and R ₁₃ can be mentioned. When R ₂₁ has a substituent, specific examples of the substituent include those similar to the substituents of R ₁₁ , R ₁₂ and R ₁₃ . R ₂₁ is preferably an aryl group or a heterocyclic group, particularly preferably a substituted or unsubstituted phenyl group.

R ₂₂ represents hydrogen, an alkylamino group, an arylamino group, or a heterocyclic amino group. Specific examples of the alkylamino group include a methylamino group, an ethylamino group, a propylamino group, a butylamino group, Examples include a dimethylamino group, a diethylamino group, and an ethylmethylamino group. Examples of the arylamino group include an anilino group, and examples of the heterocyclic group include a thiazolylamino group, a benzimidazolylamino group, and a benzothiazolylamino group. Preferably the R ₂₂ is dimethylamino group or diethylamino group.

[0083] A _1, A ₂ has the same meaning as A _1, A ₂ as described in the general formula (H-1). In the general formula (H-3), R
₃₁ and R ₃₂ each represent a monovalent substituent, and examples of the monovalent substituent include the groups mentioned as the substituents of R ₁₁ , R ₁₂ and R ₁₃ , and preferably an alkyl group, Examples include an aryl group, a heterocyclic group, an alkoxy group, and an amino group. More preferably, it is an aryl group or an alkoxy group. Particularly preferred are those in which at least one of R ₃₁ and R ₃₂ is a tert-butoxy group, and another preferred structure is that when R ₃₁ is a phenyl group, R ₃₂ is te
rt-butoxy group.

G ₃₁ and G ₃₂ each represent a-(CO) p- group,-
C (= S)-, sulfonyl group, sulfoxy group, -P (=
O) R ₃₃ - represents a group or an iminomethylene group, p is 1 or 2, R ₃₃ is an alkyl group, an alkenyl group, an alkynyl group, an aryl group, an alkoxy group, an alkenyloxy group, alkynyloxy group, an aryloxy group Or an amino group. However, when G ₃₁ is a sulfonyl group,
₃₂ is not a carbonyl group. G ₃₁ and G ₃₂ are each preferably a —CO— group, a —COCO— group, a sulfonyl group, or —CS—, and more preferably a —CO— group or a sulfonyl group.

A ₁ and A ₂ are those represented by the general formula (H-1)
₁ and A ₂ have the same meaning. In the general formula (H-4),
R ₄₁ , R ₄₂ and R ₄₃ have the same meanings as R ₁₁ , R ₁₂ and R ₁₃ in formula (H-1). R _41, preferably both the R ₄₂ and R ₄₃ is a substituted or unsubstituted phenyl group, more preferably R _41, R _42, and R
_{All of 43} are unsubstituted phenyl groups. R ₄₄ , R ₄₅
Represents an unsubstituted or substituted alkyl group, and specific examples include a methyl group, an ethyl group, a tert-butyl group, a 2-octyl group, a cyclohexyl group, a benzyl group,
And a diphenylmethyl group. R ₄₄ and R ₄₅ are preferably each an ethyl group.

A ₁ and A ₂ are those represented by the general formula (H-1)
₁ and A ₂ have the same meaning. Hereinafter, the general formulas (H-1) to (H-
Specific examples of the compound represented by 4) will be given below, but it should not be construed that the invention is limited thereto.

[0087]

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[0088]

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[0089]

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[0090]

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[0091]

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[0092]

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[0093]

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The compounds represented by the general formulas (H-1) to (H-4) can be easily synthesized by a known method. For example, US Pat. No. 5,464,738 or US Pat. It can be synthesized with reference to the specification of 5,496,695.

Other hydrazine derivatives which can be preferably used include compounds H-1 to H-2 described in US Pat. No. 5,545,505, columns 11 to 20.
9, U.S. Pat. No. 5,464,738, column 9
Compounds 1 to 12 described in Nos. 1 to 11. These hydrazine derivatives can be synthesized by a known method.

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

[0097]

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In the general formula (G), X and R are represented in a cis form, but the case where X and R are in a trans form is also included in the present invention.

In the general formula (G), X represents an electron-withdrawing group. The electron-withdrawing group is a substituent whose substituent constant σp can take a positive value. Specifically, a substituted alkyl group (eg, halogen-substituted alkyl), a substituted alkenyl group (eg, cyanovinyl), a substituted / unsubstituted alkynyl group (eg, trifluoromethylacetylenyl, cyanoacetylenyl), and a substituted aryl group (eg, cyanovinyl) Phenyl, etc.), substituted / unsubstituted heterocyclic groups (pyridyl, triazinyl, benzoxazolyl, etc.), halogen atoms, cyano groups, acyl groups (acetyl, trifluoroacetyl, formyl, etc.), thioacetyl groups (thioacetyl, thioformyl, etc.) ), An oxalyl group (such as methyloxalyl), an oxyoxalyl group (such as ethoxalyl), a thiooxalyl group (such as ethylthiooxalyl), an oxamoyl group (such as methyloxamoyl),
Oxycarbonyl group (such as ethoxycarbonyl), carboxyl group, thiocarbonyl group (such as ethylthiocarbonyl), carbamoyl group, thiocarbamoyl group, sulfonyl group, sulfinyl group, oxysulfonyl group (such as ethoxysulfonyl), thiosulfonyl group (such as ethylthio Sulfonyl), a sulfamoyl group, an oxysulfinyl group (such as methoxysulfinyl), a thiosulfinyl group (such as methylthiosulfinyl), a sulfinamoyl group, a sphinamoyl group, a phosphoryl group, a nitro group, an imino group, and N
-Carbonylimino group (such as N-acetylimino), N-
A sulfonylimino group (such as N-methanesulfonylimino), a dicyanoethylene group, an ammonium group, a sulfonium group, a phosphonium group, a pyrylium group, and an immonium group, such as an ammonium group, a sulfonium group,
Heterocyclic groups in which a phosphonium group, an immonium group or the like forms a ring are also included. A substituent having a σp value of 0.30 or more is particularly preferred.

W is hydrogen, alkyl, alkenyl, alkynyl, aryl, heterocyclic, halogen, acyl, thioacyl, oxalyl, oxyoxalyl, thiooxalyl, oxamoyl, oxycarbonyl Group, thiocarbonyl group, carbamoyl group,
Thiocarbamoyl group, sulfonyl group, sulfinyl group,
Oxysulfonyl group, thiosulfonyl group, sulfamoyl group, oxysulfinyl group, thiosulfinyl group, sulfinamoyl group, phosphoryl group, nitro group, imino group, N-carbonylimino group, N-sulfonylimino group, dicyanoethylene group, ammonium group, Represents a sulfonium group, a phosphonium group, a pyrylium group, or an immonium group. As the alkyl group represented by W,
Methyl, ethyl, trifluoromethyl, etc., alkenyl groups include vinyl, halogen-substituted vinyl, cyanovinyl, etc., alkynyl groups include acetylenyl, cyanoacetylenyl, etc., and aryl groups include nitrophenyl, cyanophenyl, pentafluorophenyl. Examples of the heterocyclic group include pyridyl, pyrimidyl, triazinyl, succinimide, tetrazolyl, triazolyl, imidazolyl, and benzoxazolyl. W is σ
A p-value is preferably a positive electron-withdrawing group, and more preferably, the value is 0.30 or more.

R represents a halogen atom, a hydroxy group, an alkoxy group, an aryloxy group, a heterocyclic oxy group, an alkenyloxy group, an acyloxy group, an alkoxycarbonyloxy group, an aminocarbonyloxy group, a mercapto group, an alkylthio group, an arylthio group, Organic or inorganic salts of ring thio group, alkenylthio group, acylthio group, alkoxycarbonylthio group, aminocarbonylthio group, hydroxy group or mercapto group (for example, sodium salt, potassium salt, silver salt, etc.), amino group, alkyl Amino group, cyclic amino group (for example, pyrrolidino group), acylamino group, oxycarbonylamino group, heterocyclic group (5 to 6
Membered nitrogen-containing heterocycle, for example, a benztriazolyl group, an imidazolyl group, a triazolyl group, a tetrazolyl group, etc.), a ureido group, or a sulfonamide group. X and W, X
And R may combine with each other to form a cyclic structure. As the ring formed by X and W, for example, pyrazolone,
Pyrazolidinone, cyclopentanedione, β-ketolactone, β-ketolactam and the like. Of the groups represented by R, preferred are a hydroxy group, a mercapto group, an alkoxy group, an alkylthio group, a halogen atom, an organic or inorganic salt of a hydroxy group or a mercapto group, and a heterocyclic group, more preferably a hydroxy group. And an organic or inorganic salt of an alkoxy group, a hydroxy group or a mercapto group, and a heterocyclic group, and particularly preferably an organic or inorganic salt of a hydroxy group, a hydroxy group or a mercapto group.

Further, among the groups represented by X and W,
Those having a thioether bond in the substituent are preferred.

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

[0104]

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In the general formula (P), Q represents a nitrogen atom or
Represents a phosphorus atom;₁, R_Two, R_ThreeAnd R_FourIs hydrogen
X represents an atom or a substituent;^-Represents an anion. What
Contact, R ₁~ R_FourMay be connected to each other to form a ring.

As the substituent represented by R _{1 to} R ₄ , an alkyl group (methyl group, ethyl group, propyl group, butyl group,
Hexyl group, cyclohexyl group, etc., alkenyl group (allyl group, butenyl group, etc.), alkynyl group (propargyl group, butynyl group, etc.), aryl group (phenyl group, naphthyl group, etc.), heterocyclic group (piperidinyl group, piperazinyl group) , Morpholinyl group, pyridyl group, furyl group, thienyl group, tetrahydrofuryl group, tetrahydrothienyl group,
Sulfolanyl group), an amino group and the like.

The ring which may be formed by connecting R _{1 to} R ₄ to each other includes a piperidine ring, a morpholine ring, a piperazine ring,
Examples include a quinuclidine ring, a pyridine ring, a pyrrole ring, an imidazole ring, a triazole ring, and a tetrazole ring.

The groups represented by R _{1 to} R ₄ may each have a substituent such as a hydroxyl group, an alkoxy group, an aryloxy group, a carboxyl group, a sulfo group, an alkyl group, an aryl group. R ₁ , R ₂ , R ₃ and R ₄ are each preferably a hydrogen atom or an alkyl group.

Examples of the anion represented by X ⁻ include inorganic and organic anions such as a halogen ion, a sulfate ion, a nitrate ion, an acetate ion and a p-toluenesulfonic acid ion.

More preferably, the following general formulas (Pa) and (P
The compound represented by b) or (Pc) and the compound represented by the following general formula (T) are used.

[0111]

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Wherein A ¹ , A ² , A ³ , A ⁴ and A ⁵ are
Each represents a group of non-metallic atoms for completing a nitrogen-containing heterocyclic ring, and may contain an oxygen atom, a nitrogen atom, and a sulfur atom, and may be condensed with a benzene ring. The heterocyclic ring composed of A ¹ , A ² , A ³ , A ⁴ and A ⁵ may have a substituent and may be the same or different. As the substituent, an alkyl group, an aryl group, an aralkyl group, an alkenyl group, an alkynyl group, a halogen atom, an acyl group, an alkoxycarbonyl group, an aryloxycarbonyl group,
Sulfo group, carboxy group, hydroxy group, alkoxy group, aryloxy group, amide group, sulfamoyl group,
Represents a carbamoyl group, a ureido group, an amino group, a sulfonamide group, a sulfonyl group, a cyano group, a nitro group, a mercapto group, an alkylthio group, or an arylthio group. A ¹ ,
Preferred examples of A ² , A ³ , A ⁴ and A ⁵ include 5 to 6
Member rings (rings such as pyridine, imidazole, thiozole, oxazole, pyrazine and pyrimidine) can be mentioned, and a more preferred example is a pyridine ring.

_BP represents a divalent linking group, and m represents 0 or 1. Examples of the divalent linking group include an alkylene group, an arylene group, an alkenylene _{group, -SO 2 -, - SO -} , -
O -, - S -, - CO -, - N (R 6) - (R 6 is an alkyl group, an aryl group, a hydrogen atom) represents what is configured alone or in combination. Preferred examples of B _p include an alkylene group and an alkenylene group.

R ¹¹ , R ¹² and R ¹⁵ each have 1 to 1 carbon atoms
Represents 20 alkyl groups. R ¹¹ and R ¹² may be the same or different. The alkyl group represents a substituted or unsubstituted alkyl group, and examples of the substituent include A ¹ , A ² , A
The substituents are the same as those described as the substituents of ³ , A ⁴ and A ⁵ .

Preferable examples of R ¹¹ , R ¹² and R ¹⁵ are each an alkyl group having 4 to 10 carbon atoms. More preferred examples include a substituted or unsubstituted aryl-substituted alkyl group.

[0116] X _p ^- is a counter ion necessary to balance the charge of the whole molecule, for example chloride, bromide,
It represents iodine ion, nitrate ion, sulfate ion, p-toluenesulfonate, oxalate and the like. n _p represents the number of counter ions required to balance the charge of the whole molecule, and n _p is 0 in the case of an internal salt.

[0117]

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The substituents R ₅ and R ₆ of the phenyl group of the triphenyltetrazolium compound represented by the general formula (T),
R ₇ is preferably a hydrogen atom or a compound having a negative Hammett's sigma value (σp) indicating electron-withdrawing degree.

The Hammett's sigma value at the phenyl group is described in many literatures, for example, Journal of Medical Chemistry.
chemistry, 20, 304, 1977. The group having a particularly preferable negative sigma value is, for example, a methyl group (σp = −0.17 or less, σp value), and an ethyl group (−). 0.15), cyclopropyl group (-0.21), n-propyl group (-0.13), is
o-propyl group (-0.15), cyclobutyl group (-
0.15), n-butyl group (-0.16), isobutyl group (-0.20), n-pentyl group (-0.15), cyclohexyl group (-0.22), amino group (-0 .6
6), acetylamino group (-0.15), hydroxyl group (-0.37), methoxy group (-0.27), ethoxy group (-0.24), propoxy group (-0.25), butoxy Group (-0.32), pentoxy group (-0.34)
These are all useful as substituents of the compound of the general formula (T).

N represents 1 or 2, and examples of the anion represented by X _T ^n- include halogen ions such as chloride ion, bromide ion and iodide ion, nitric acid, sulfuric acid, and the like.
Acid radicals of inorganic acids such as perchloric acid, acid radicals of organic acids such as sulfonic acid and carboxylic acid, anionic activators, specifically p-
Lower alkylbenzene sulfonic acid anions such as toluene sulfonic acid anion; higher alkyl benzene sulfonic acid anions such as p-dodecyl benzene sulfonic acid anion; higher alkyl sulfate anions such as lauryl sulfate anion; boric acid anions such as tetraphenyl boron; Dialkyl sulfosuccinate anions such as 2-ethylhexyl sulfosuccinate anion,
Examples thereof include higher fatty acid anions such as cetyl polyethenoxy sulfate anion, and polymers having an acid radical attached to a polymer such as polyacrylate anion.

The above quaternary onium compound can be easily synthesized according to a known method. For example, the above tetrazolium compound can be obtained from Chemical Reviews vol. 55
p. 335-483 can be referred to.

As the contrast agents, the following general formulas (A) to (A)
The compound represented by (D), hydroxylamine, alkanolamine and ammonium phthalate can also be used.

[0123]

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The compound represented by formula (A) will be described. In the general formula (A), EWD represents an electron-withdrawing group, and R ⁶ , R ⁷ and R ⁸ each represent a hydrogen atom or a monovalent substituent. However, at least one of R ⁷ and R ⁸ is a monovalent substituent. Here, the electro-attractive group represented by EWD is a substituent whose Hammett's substituent constant σp can take a positive value, specifically, a cyano group,
Alkoxycarbonyl group, aryloxycarbonyl group, carbamoyl group, sulfamoyl group, alkylsulfonyl group, arylsulfonyl group, nitro group, halogen atom, perfluoroalkyl group, acyl group, formyl group, phosphoryl group, carboxy group (or salt thereof) , A sulfo group (or a salt thereof), a saturated or unsaturated heterocyclic group, an alkenyl group, an alkynyl group, an acyloxy group, an acylthio group, a sulfonyloxy group, and an aryl group substituted with these electron-withdrawing groups. . These groups may have a substituent. Specific compounds include, for example, compounds disclosed in U.S. Pat. No. 5,545,515, JP-A-11-119372 and the like.

The compound represented by the formula (B) is described
I will tell. In the general formula (B), R ⁹Is a hydrogen atom, al
Kill group, alkenyl group, alkoxy group, alkylthio,
Amide group, aryl group, aralkyl group, aryloxy
Group, arylthio group, anilino group, heterocyclic group, heterocyclic group
Represents a xy or heterocyclic thio group, but is an alkyl group
Are preferably, and more preferably a methyl group or an ethyl group.
New

R ¹⁰ is a hydrogen atom, an alkyl group, an alkenyl group, an alkoxy group, an alkylthio, an amide group, an aryl group, an aralkyl group, an aryloxy group, an arylthio group, an anilino group, a heterocyclic group, a heterocyclic oxy group, or a heterocyclic group. Represents a thio group, a hydrazino group, an alkylamino group, a sulfonylamino group, a ureido group, an oxycarbonylamino group, an alkynyl group or an unsubstituted amino group, but is an aryl group, a heterocyclic group, a heterocyclic oxy group, or a heterocyclic thio group. And more preferably a heterocyclic oxy group and a heterocyclic thio group. Specific examples of the heterocyclic oxy group include a pyridyloxy group, a pyrimidyloxy group, an indolyloxy group, a benzothiazolyloxy group, a benzimidazolyloxy group, a furyloxy group, a thienyloxy group, a pyrazolyloxy group, and an inidazolyloxy group Examples include a furylthio group, a thienylthio group, a pyrazolylthio group, and an inidazolylthio group. R ¹⁰ is preferably a pyridyloxy group or a thienyloxy group.

X represents a hydrogen atom, an alkyl group, a carbamoyl group or an oxycarbonyl group. X is preferably a hydrogen atom. R ⁹ and R ¹⁰ may combine to form a 5- to 7-membered ring. Specific compounds include, for example, the compounds disclosed in US Pat. No. 5,545,507.

The compound represented by the general formula (C) is described below.
I will tell. In the general formula (C), R ¹¹Is an alkyl group,
Lucenyl group, alkoxy group, alkylthio, amide group,
Aryl group, aralkyl group, aryloxy group, aryl
Represents a luthio group, anilino group or a heterocyclic group, but is an aryl
Group, heterocyclic group, heterocyclic oxy group, heterocyclic thio group
Is preferred. More preferably a heterocyclic oxy group, a heterocyclic thio group
O group. Specifically, as the heterocyclic oxy group,
Ruoxy group, pyrimidyloxy group, indolyloxy
Group, benzothiazolyloxy group, benzimidazolyloxy
Xyl group, furyloxy group, thienyloxy group, pyrazoly
And an indazolyloxy group. Duplicate
Specific examples of the ring thio group include a pyridylthio group and a pyrimidyl group.
Luthio, indolylthio, benzothiazolylthio
Group, benzimidazolylthio group, furylthio group, thienyl
Luthio, pyrazolylthio, inidazolylthio, etc.
No. R¹¹As a pyridyloxy group,
A thienyloxy group. Specific compounds include, for example,
The compound disclosed in US Pat. No. 5,558,983 is
No.

The compound represented by formula (D) is described
I will tell. In the general formula (D), R ¹²Is Benzhydro
Nucleus, diphenylphosphine nucleus, triphenylmethane
Nucleus, N, N'-dialkylpiperazine nucleus, 3-pyrroli
Nucleus, xanthene nucleus, 9,10-dihydroanthracene
Nucleus, 9-hydroxyfluorene nucleus, allyl-beta-ke
Toester nucleus, aldehyde nucleus, alkyl-beta-keto
Ester nucleus, oxime nucleus, amide oxime nucleus, benzur
Nucleotide oxime nucleus, acetophenone oxime nucleus, cap
Lolactam oxime core, ethyl benzoyl acetate
Nucleus, pivalaldehyde nucleus or ethyl isobutyl acetate
Nucleus. Specific compounds include, for example, U.S. Pat.
No. 5,637,449.
You.

Specific examples of the compounds (high contrast agents) represented by formulas (A) to (D) of the present invention are shown below, but are not limited thereto.

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The amount of the above-mentioned toning agent is preferably in the range of 1 × 10 ^-6 to 1 mol per mol of silver, and more preferably in the range of 1 × 10 ^{-5 to} 5 mol.
X10 ^-1 mol is particularly preferred.

The heat-developable recording material of the present invention preferably contains an oxidizing agent for suppressing fog. The oxidizing agent used in the present invention may be any oxidizing agent as long as it reduces fog during storage. As such an oxidizing agent, preferably, for example, JP-A-50-119
No. 624, No. 50-120328, No. 51-1213
No. 32, No. 54-58022, No. 56-70543
Nos. 56-99335, 59-90842, 61-129642, 62-129845, JP-A-6-208191, 7-5621, and 7-27.
No. 81, 8-15809, U.S. Pat. No. 5,340,
No. 712, No. 5,369,000, No. 5,46
No. 4,737, No. 3,874,946, No. 4,7
No. 56,999, No. 5,340,712, European Patent Nos. 605981A1, 62262666A1 and 63.
No. 1176A1, JP-B No. 54-165, JP-A-7-2
No. 781, U.S. Pat. Nos. 4,180,665 and 4,442,202 can be used, but polyhalogen compounds represented by the following general formula (I) are preferred. It is.

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In the formula, A represents an aliphatic group, an aromatic or heterocyclic group, and X ₁ , X ₂ and X ₃ each represent a hydrogen atom or a halogen atom, which may be the same or different. Y
Represents a divalent linking group. n represents 0 or 1.

In the present invention, the amount of the oxidizing agent to be added is preferably 1 × 10 ^-4 to 1 mol per mol of silver, and more preferably 1 × 10 ^-4 to 1 mol.
More preferably, it is 10 ^{-3 to} 0.5 mol.

At least one layer on the image recording layer side of the heat-developable recording material of the present invention preferably contains a fatty acid and a derivative thereof. Examples of the fatty acid include lauric acid, myristic acid, palmitic acid, and the like. stearic acid,
Behenic acid, oleic acid, linoleic acid, linolenic acid, elaidic acid, and as fatty acid esters, for example, butyl stearate, amyl stearate, octyl stearate, butyl palmitate, butyl myristate,
Butoxyethyl stearate, oleyl oleate, butoxyethyl stearate.

As the support of the heat-developable recording material, paper, polyethylene-coated paper, polypropylene-coated paper, parchment, cloth, metal (eg, aluminum, copper, magnesium, zinc) sheet or thin film, glass, Glass and plastic films coated with metal (eg, chromium alloy, steel, silver, gold, platinum) are used. Examples of the plastic used for the support include polyalkyl methacrylate (eg, polymethyl methacrylate), polyester (eg, polyethylene terephthalate), polyvinyl acetal, polyamide (eg, nylon), and cellulose ester (eg, cellulose nitrate, cellulose). Acetate, cellulose, acetate propionate, cellulose acetate butyrate).
The support may be coated with a polymer. Examples of polymers include polyvinylidene chloride, acrylic acid based polymers (eg,
Polyacrylonitrile, methyl acrylate), polymers of unsaturated dicarboxylic acids (eg, itaconic acid, acrylic acid), carboxymethylcellulose and polyacrylamide. Copolymers may be used. Instead of coating with a polymer, an undercoat layer containing a polymer may be provided. In order to improve the dimensional characteristics of the support, it is effective to perform annealing on the support under low tension. For example, Japanese Patent Publication No. 60-21616, U.S. Pat.
No. 9,684, RD 19809, JP-A-8-2115
No. 47, No. 10-10676, No. 10-10677
Nos. 11-47676, 11-65025, 11-138628, 11-138648, 1
Nos. 1-221892, 11-333922, 11
It is preferable to appropriately combine known methods described in, for example, JP-A-333923. The tension at the time of heat treatment of the support, preferably at the time of applying the undercoat layer, is 0.4 to 80 N / cm ² , more preferably ^{2 to} 60 N / cm ² , and further preferably 1 to 60 N / cm ² .
0 to 50 N / cm ² . The heat treatment temperature or drying temperature is 70 to 220 ° C, more preferably 80 to 200 ° C.
And more preferably 90 to 190 ° C. The heat treatment time or the drying time is preferably from 1 to 30 minutes, more preferably from 2 to 20 minutes, and still more preferably from 3 to 30 minutes.
15 minutes.

As a preferred example of the layer constitution in the present invention, an undercoat layer is provided on one surface of the support, an image recording layer is provided thereon, and a surface protective layer is further provided thereon.
The undercoat layer (image recording layer side) is preferably composed of two or more layers, and the total dry film thickness of the undercoat layer is preferably from 0.2 to 5 μm, more preferably from 0.5 to 3 μm. The dry film thickness of the image recording layer is preferably from 5 to 13 μm, more preferably from 7 to 11 μm. The dry thickness of the surface protective layer is preferably from 2 to 10 μm, more preferably from 4 to 8 μm. The surface protective layer preferably contains a matting agent. The average particle size of the matting agent is preferably from 1 to 10 μm, more preferably from 3 to 7 μm. As the matting agent, a known filler can be used, but it is preferable to use an organic powder such as polymethyl methacrylate.

An undercoat layer is provided on the surface opposite to the image recording layer with the support therebetween, and a back coat layer is provided thereon.
Further, it is preferable to provide a back coat surface protective layer thereon. The undercoat layer (backcoat layer side) is preferably composed of two or more layers, and the undercoat layer closest to the support is
It is preferable that the antistatic layer contains a conductive metal oxide and / or a conductive polymer. As the conductive metal oxide, SnO ₂ surface-treated with Sb is preferable, and as the conductive polymer, polyaniline is preferable. The total dry film thickness of the undercoat layer is preferably from 0.2 to 4 μm,
More preferably, it is 2 μm. The dry film thickness of the back coat layer is preferably 2 to 10 μm, and 4 to 8 μm.
More preferably, it is μm. The back coat layer preferably contains an antihalation dye. The dry film thickness of the back coat surface protective layer is preferably from 2 to 10 μm, more preferably from 4 to 8 μm. The back coat surface protective layer preferably contains a matting agent. As the matting agent, a known filler can be used, but it is preferable to use an organic powder such as polymethyl methacrylate. The average particle size of the matting agent is 1-10μ
m is preferable, and 3 to 7 μm is more preferable.
The effects of the present invention can be better exhibited by adopting the above layer configuration and film thickness configuration.

The photothermographic material of the present invention comprises an image recording layer,
In the image recording protective layer, and other layers, various additives known in the art other than those described above, for example, a color tone agent, a surfactant, an antioxidant, a stabilizer, a plasticizer, an ultraviolet absorber, and a coating aid. An agent may be added.

A known technique can be applied to the exposure of the photothermographic material of the present invention. For example, argon ion laser (488 nm), He-Ne laser (633 nm),
Lasers such as a red semiconductor laser (670 nm) and an infrared semiconductor laser (780 nm, 820 nm) are preferably used.

In the heat development of the photothermographic material of the present invention, the heating temperature is preferably from 80 ° C. to 200 ° C., and more preferably from 100 ° C. to 150 ° C. If the heating temperature is lower than 80 ° C., a sufficient image density cannot be obtained in a short time, and if the heating temperature is higher than 200 ° C., the binder is melted and adversely affects not only the image itself but also transportability such as transfer to a roller and a developing machine. Effect.

In the heat development of the photothermographic material of the present invention, a transfer type heat developing machine is used, and the transfer speed is 22 mm /.
It is preferable to carry out the heat development at a rate of not less than seconds and not more than 40 mm / sec from the viewpoint that the object of the present invention can be more highly achieved.

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EXAMPLES Hereinafter, the present invention will be described specifically with reference to Examples, but the present invention is not limited thereto.

Example 1 (Preparation of an undercoated PET support) A commercially available biaxially stretched and heat-fixed polyethylene terephthalate (PET) film having a thickness of 125 μm was used at 180 ° C. under a tension of 1.47 × 1.
0 was performed conveying heat treatment for 1 minute at ^{5 Pa (= 1.5kg / cm 2} ). Young's modulus of the PET film MD direction 750kg / mm ^2, TD direction was 740kg / mm ^2. The both surfaces were subjected to a corona discharge treatment of 8 W / m ² · min, and one surface was coated with the following undercoating solution a-1 so as to have a dry film thickness of 0.8 μm, and dried to form an undercoat layer A-1.
On the other side, an undercoating coating solution b-1 having been subjected to the following antistatic processing was applied so as to have a dry film thickness of 0.8 μm and dried to obtain an antistatic processing undercoat layer B-1. (Undercoating coating solution a-1) Copolymer latex liquid of butyl acrylate (30% by mass), tert-butyl acrylate (20% by mass), styrene (25% by mass), and 2-hydroxyethyl acrylate (25% by mass) Solid content 30%) 270 g Surfactant (C-1) 0.6 g Hexamethylene-1,6-bis (ethylene urea) 0.8 g Polystyrene fine particles (average particle size 3 μm) 0.05 g Colloidal silica (average particle size 90 nm) ) 0.1 g finished to 1 liter with water (undercoating coating solution b-1) SnO ₂ / Sb (9/1 mass ratio, average particle size 0.18 μm) 120 g butyl acrylate (30 mass%), styrene (20 mass%) Glycidyl acrylate (40% by mass) copolymer latex liquid (solid content 30%) 270 g Surfactant (C-1) g hexamethylene-1,6-bis (ethyleneurea) finish 1l in 0.8g water.

Subsequently, the undercoat layer A-1 and the undercoat layer B
-1 was subjected to a corona discharge of 8 W / m ² .min. On the undercoat layer A-1, and the following undercoat upper layer coating solution a
-2 is applied as an undercoat layer A-2 so as to have a dry film thickness of 0.9 μm, and the following undercoat upper layer coating solution b-2 is formed on the undercoat layer B-1 so as to have a dry film thickness of 0.2 μm. Was provided as an undercoat layer B-2 having an antistatic function. (Undercoat upper layer coating solution a-2) Binder (E in Table 1) 50 g Surfactant (C-1) 0.2 g Surfactant (C-2) 0.2 g Crosslinking agent (C-3) 0.1 g Silica particles (average particle size: 3 μm) 2.0 g Finished to 1 liter with water. (Undercoat upper layer coating solution b-2) Polymer (C-4) 60 g Latex solution containing (C-5) as a component (solid content 20%) 80 g Ammonium sulfate 0.5 g Crosslinking agent (C-6) 12 g Polyethylene glycol (weight) Average molecular weight 600) 6g finish to 1l with water

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(Heat Treatment of Support) In the above-mentioned undercoat drying step of the undercoated support, the support was heated at 140 ° C.
Thereafter, it was gradually cooled. (Preparation of 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.
g of an aqueous solution containing sodium chloride, potassium bromide and potassium iodide in a molar ratio of (60/38/2) and [Ir (NO) Cl ₅ ] salt in an amount of 1 × 10 ⁻⁶ per mole of silver. The mol and rhodium chloride salt were added by the controlled double jet method at 1 × 10 ⁻⁶ mol per mol of silver while keeping the pAg at 7.7. Thereafter, 4-hydroxy-6-methyl-1,3,3a, 7-tetrazaindene was added, the pH was adjusted to 8.0 and the pAg was adjusted to 6.5 with NaOH, and reduction sensitization was performed. .06μ
m, a coefficient of variation of the particle size distribution of 10%, a coefficient of variation of the projected diameter area of 8%, and a silver halide emulsion having cubic silver iodobromide grains having a [100] face ratio of 87%. The resulting mixture was subjected to coagulation sedimentation and desalting to obtain a silver halide emulsion A. (Preparation of Na Behenate Solution) In 945 ml of pure water, 32.4 g of behenic acid, 9.9 g of arachidic acid and 5.6 g of stearic acid were dissolved at 90 ° C. Next, while stirring at a high speed, 98 m of a 1.5 mol / l sodium hydroxide aqueous solution
1 was added. Next, after adding 0.93 ml of concentrated nitric acid, 5
The mixture was cooled to 5 ° C and stirred for 30 minutes to obtain a sodium behenate solution. (Preparation of Preform Emulsion of Silver Behenate and Silver Halide Emulsion A) 1.51 g of the silver halide emulsion A was added to the above sodium behenate solution, and the pH was adjusted with a sodium hydroxide solution.
After adjusting to 8.1, 1 mol / l of 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 obtained silver behenate was particles having an average particle size of 0.8 μm and a variation coefficient of the particle size distribution of 8%. After the floc of this dispersion was formed, water was removed, washed with water six times and water was removed, and dried to obtain a preform emulsion. (Preparation of photosensitive emulsion A) -S
544 g of a methyl ethyl ketone / toluene solution (17% by mass) of O ₃ Na-containing polyvinyl butyral resin and 107 g of toluene were gradually added and mixed.
Dispersion was performed at 30 ° C. for 10 minutes at 4000 psi with a media disperser using a ZrO ₂ bead mill of size to prepare photosensitive emulsion A. (Preparation of Photothermographic Material Sample) The following layers were simultaneously coated on both sides of the support to prepare a photothermographic material sample.
The drying was performed at 60 ° C. for 15 minutes. (Coating on the back side) On the undercoat layer B-2 of the support, the back coating layer coating solution having the following composition has a dry film thickness of 6 μm and the back layer surface protection layer coating solution has a dry film thickness of 3.5 μm. At the same time. (Coating solution for back coat layer) Cellulose acetate butyrate 15 g (10% methyl ethyl ketone solution) Dye-A 0.007 g Dye-B 0.007 g Matting agent: Monodisperse silica having a variation coefficient of particle size distribution of 15% and an average particle size of 5 μm 0.09 g Matting agent: monodisperse silica having a coefficient of variation in particle size distribution of 15% and an average particle size of 15 μm 0.02 g C ₈ F ₁₇ (CH ₂ CH ₂ O) ₁₂ C ₈ F ₁₇ 0.05 g C ₉ F ₁₇ − C ₆ H ₄ —SO ₃ Na 0.01 g Stearic acid 0.1 g

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(Back layer surface protective layer) Cellulose acetate butyrate 15 g (10% methyl ethyl ketone solution) Matting agent: Monodisperse silica having a variation coefficient of particle size distribution of 15% and an average particle size of 5 μm (1% by mass of the total mass of silica) 0.1 g Matting agent: monodisperse silica having a coefficient of variation in particle size distribution of 15% and an average particle size of 15 μm (surface treated with aluminum of 1% by mass of the total mass of silica) 0.04 g C ₈ F ₁₇ ( (CH ₂ CH ₂ O) ₁₂ C ₈ F ₁₇ 0.05 g C ₉ F ₁₇ —C ₆ H ₄ —SO ₃ Na 0.01 g Stearic acid 0.1 g (coating on image recording layer side) (image recording layer) on support On the undercoat layer A-2 provided in the above, a coating solution having the following composition was applied so that the applied silver amount was 1.0 g / m ² and the dry film thickness was 10.0 μm.

Photosensitive emulsion A 240 g Sensitizing dye A (0.1% methanol solution) 1.7 ml Dye-A 0.07 g Pyridinium bromide perbromide (6% methanol solution) 3 ml Calcium bromide (0.1% methanol solution) Solution) 1.7 ml Oxidizing agent-1 (10% methanol solution) 1.2 ml 2-Chlorobenzoylbenzoic acid (12% methanol solution) 9.2 ml 2-mercaptobenzimidazole (1% methanol solution) 11 ml Binder 1 ( (Described in Table 1) Amount described in Table 1 Tribromomethylsulfoquinoline (5% methanol solution) 17 ml Compound A 0.1 g Compound B 0.1 g Compound C 0.1 g Hydrazine derivative (compound described in Table 1) 4 g Hardening agent (compound shown in Table 1 other than hydrazine derivative) 0.3 g Phthalazine 0 2.6 g 4-methylphthalic acid 0.25 g tetrachlorophthalic acid 0.2 g matting agent (coefficient of variation in particle size distribution: 15%, monodisperse silica having an average particle size of 5 μm, surface treatment with aluminum of 1% by mass of the total mass of silica) 0.3 g Reducing agent-1 (20% methanol solution) 20.5 ml Isocyanate compound 0.5 g (Desmodur N3300 manufactured by Mobay Corporation) Stearic acid 0.5 g Butyl stearate 0.5 g α-alumina (Mohs hardness 9) 5g

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(Image Recording Protective Layer) A coating solution having the following composition was simultaneously coated on the image recording layer so as to have a dry film thickness of 6 μm.

Acetone 5 g Methyl ethyl ketone 21 g Binder 2 (described in Table 1) Amount described in Table 1 Methanol 7 g Phthalazine 0.25 g Reducing agent-1 (20% methanol solution) 10 g Matting agent (Coefficient of variation of particle size distribution 15%, Monodisperse silica having an average particle size of 5 μm, surface-treated with 1% by mass of aluminum based on the total mass of silica 0.2 g Matting agent (monodisperse silica having a variation coefficient of particle size distribution of 15% and average particle size of 20 μm) 0.04 g CH ₂ ＣＨCHSO ₂ CH ₂ CH ₂ OCH ₂ CH ₂ SO ₂ CH = CH ₂ 0.035 g C ₁₂ F ₂₅ (CH ₂ CH ₂ O) _{10 C 12 F 25 0.01g C 8 F} 17 -C 6 H 4 -SO 3 Na 0.01g stearate 0.1g butyl stearate 0.1g alpha-alumina ( 9) 0.1 g of the photothermographic material sample on which the coating film was formed, after removing the binder and observing the sample with an electron microscope using a replica method, the organic silver salt particles had a major axis diameter of 0.5 ± 0.5%. 0.05
μm, short axis diameter 0.4 ± 0.05μm, thickness 0.01μm
Were 90% of the total organic silver salt particles and the particle size distribution had a coefficient of variation of 5%.

The above photothermographic material sample was placed in a dark room for 30 minutes.
It was cut to a length of 50 m with a width of 10 cm and wound around a core made of cardboard having an inner diameter of 10 cm to form a roll. Further, in a dark room, the produced sample was wound with a packaging material of 60 cm × 2 m.

Example 2 (Preparation of silver halide emulsion B) After dissolving 22 g of phthalated gelatin and 30 mg of potassium bromide in 700 ml of water and adjusting the pH to 5.0 at a temperature of 40 ° C, silver nitrate 1
159 ml of an aqueous solution containing 8.6 g and an aqueous solution containing potassium bromide were added over 60 minutes by a control double jet method while maintaining the pAg at 7.7. Then silver nitrate 5
476 ml of an aqueous solution containing 5.4 g and K ₃ [IrCl ₆ ] ₃
8 × 10 ^-6 mol / l and potassium bromide 1 mol /
An aqueous solution containing 1 liter was added over 30 minutes by the control double jet method while maintaining the pAg at 7.7. Thereafter, pH was adjusted to 5.9 and pAg to 8.0. The obtained silver halide grains were cubic grains having an average grain size of 0.07 μm, a variation coefficient of the projected area diameter of 8%, and a (100) area ratio of 86%. The above silver halide emulsion B was heated to a temperature of 60 ° C. to give 8.5 × 10 ⁻⁵ mol of sodium thiosulfate and 1.1 × 10 ⁻⁵ mol of 2,3,4,5 mol per mol of silver. , 6
-Pentafluorophenyldiphenylsulfin selenide, 2 × 10 ⁻⁶ mol of the following tellurium compound-1, 3.3 ×
10 ^-6 mol of chloroauric acid, 2.3 × 10 ^-4 mol of thiocyanic acid were added, and the mixture was aged for 120 minutes. Thereafter, the temperature was raised to 50 ° C., 8 × 10 ⁻⁴ mol of the following sensitizing dye B was added with stirring, and further 3.5 × 10 ⁻² mol of potassium iodide was added, followed by stirring for 30 minutes. The mixture was rapidly cooled to 30 ° C. to complete the preparation of silver halide grains.

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(Preparation of organic silver salt microcrystal dispersion) 40 g of behenic acid, 7.3 g of stearic acid and 500 ml of distilled water were added to 9
The mixture was mixed at 0 ° C. for 15 minutes, 187 ml of a 1 mol / l NaOH aqueous solution was added over 15 minutes with vigorous stirring, and 61 ml of a 1 mol / l nitric acid aqueous solution was added, followed by cooling to 50 ° C. Next, 124 ml of a 1 mol / liter aqueous silver nitrate solution was added, and the mixture was stirred for 30 minutes.
Thereafter, the solid content was filtered by suction filtration, and the solid content was washed with water until the electric conductivity of the filtrate reached 30 μS / cm. The solid content thus obtained was handled as a wet cake without drying, and 12 g of polyvinyl alcohol and 1 liter of water were added to a wet cake equivalent to 34.8 g of dry solid content.
50 ml was added and mixed well to form a slurry. Prepare 840 g of zirconia beads having an average diameter of 0.5 mm, put them in a vessel together with the slurry, and use a disperser (（G-
The mixture was dispersed for 5 hours with a sand grinder mill (manufactured by Imex Co., Ltd.) to obtain a dispersion of organic silver salt microcrystals having a volume-weighted average of 1.5 μm. Particle size measurements are available from Malvern
Instruments Ltd. MasterS
Performed with aizerX. (Preparation of material solid fine particle dispersion) Tetrachlorophthalic acid, 4-methylphthalic acid, 1,1-bis (2-hydroxy-3,5-dimethylphenyl) -3,5,5-trimethylhexane, phthalazine, and trimethylphthalic acid Solid particulate dispersions were prepared for each of the bromomethylsulfoquinolines.

Preparation of solid fine particle dispersion of tetrachlorophthalic acid: 0.81 g of hydroxypropylcellulose and 94.2 ml of water were added, stirred well, and left as a slurry for 10 hours. Thereafter, 100 ml of zirconia beads having an average diameter of 0.5 mm and a slurry were put together in a vessel, and dispersed in a dispersing machine of the same type as that used for preparing the silver salt of organic acid microcrystals for 5 hours. A solid microcrystalline dispersion of the acid was obtained. 70% by mass of the solid fine particles had a particle size of 1.0 μm or less.

With respect to the other materials, the amount of the dispersant used and the dispersion time were appropriately changed in order to obtain a desired average particle size, and solid fine particle dispersions were obtained. (Preparation of Photothermographic Material Sample) The following layers were simultaneously coated on an undercoated PET support prepared in the same manner as in Example 1 to prepare a photothermographic material sample. The drying was performed at 60 ° C. for 15 minutes. (Back surface side coating) On the undercoat layer B-2 provided on the support, a backcoat layer coating solution having the following composition was dried to a thickness of 6 μm.
m, a coating liquid for the back layer surface protective layer was simultaneously applied thereon so that the dry film thickness became 3.5 μm, and dried. (Coating solution for back coat layer) Polyvinyl alcohol (10% aqueous solution) 15 g Dye-A 0.007 g Dye-B 0.007 g Matting agent (monodisperse silica having a variation coefficient of particle size distribution of 15% and an average particle size of 5 μm) 09 g Matting agent (monodisperse silica having a variation coefficient of particle size distribution of 15% and an average particle size of 17 μm) 0.01 g sodium dodecylbenzenesulfonate 0.05 g stearic acid 0.1 g (coating solution for back layer surface protective layer) Polyvinyl alcohol ( 10 g aqueous solution) 15 g Matting agent (Coefficient of variation of particle size distribution 15%, silica A having an average particle size of 5 μm, surface treatment with aluminum of 1 mass% of the total mass of silica) 0.5 g Matting agent (coefficient of variation of particle size distribution) 15%, silica A having an average particle size of 15 μm, surface treatment with aluminum of 1% by mass of the total mass of silica) 0.04 g Stearic acid g (image recording layer side coating) coating silver amount a coating solution having the following composition on a support provided with a subbing layer A-2 is 1.0 g / m ^2, coating as a dry film thickness of 10.0μm did. (Image recording layer coating solution) The following binder and material were added to the previously prepared organic silver salt microcrystal dispersion to prepare an image recording layer coating solution.

Organic acid silver microcrystal dispersion 0.95 mol Silver halide emulsion B 0.05 mol Luster 3307B (Tg = 13 ° C., manufactured by Dainippon Ink and Chemicals, Inc.) 430 g as solids Binder 1 (see Table 1) Description) Amount shown in Table 1 as solid content Reducing agent-1 (20% methanol solution) 98 g Tribromomethylsulfonylbenzene 12 g Hydrazine derivative (compound described in Table 1) 1.5 g Hardening agent (other than hydrazine derivative) Compounds listed in Table 1) 1.5 g Phthalazine 9.2 g 4-Methylphthalic acid 7 g Tetrachlorophthalic acid 5 g Matting agent (coefficient of variation in particle size distribution: 15%, monodisperse silica having an average particle size of 5 μm, 1 of the total mass of silica) 2.0 g Stearic acid 0.5 g Butyl stearate 0.5 g α-alumina Scan hardness 9) 0.5 g (were simultaneously coated so that the liquid of the image recording protective layer) The following composition on an image recording layer.

Water 26 g Binder 2 (described in Table 1) Amount described in Table 1 Phthalazine 0.25 g Reducing agent-1 (20% methanol solution) 10 g Matting agent (Coefficient of variation of particle size distribution 15%, average particle size 5 μm) 0.5 g of a matting agent (silica having a particle size distribution variation coefficient of 15%, an average particle diameter of 20 μm, and aluminum of 1 mass% of the total mass of silica) surface-treated _{ones) 0.04g C 8 F 17 -C 6} H 4 -SO 3 Na 0.02g stearate 0.1g butyl stearate 0.1g alpha-alumina (Mohs hardness: 9) was 0.1g film forming Using a photothermographic material sample, after removing the binder, the electron silver microparticles were observed by an electron microscope using a replica method.
m, tabular grains having a minor axis diameter of 0.4 ± 0.05 μm and a thickness of 0.01 μm were grains having a coefficient of variation of 5% in particle size distribution, which was 90% of all organic silver salt grains.

The produced photothermographic material was placed in a dark room for 30 minutes.
The sample was cut into a length of 50 m and a width of 10 cm, wound around a core made of cardboard having an inner diameter of 10 cm, and a roll-shaped sample was prepared. Further, the sample prepared in the dark room was wound with a packaging material of 60 cm × 2 m. (Exposure and development treatment)
using a Dotex 2dry manufactured by Scitex, an image setter equipped with a
A halftone dot is exposed so as to change the exposure amount in 5% steps with a 0 line, and after passing through a pre-heating section at 110 ° C. for 15 seconds,
Thermal development was performed at 120 ° C. for 15 seconds while performing horizontal conveyance in an oven. At that time, exposure and development were performed at 23 ° C and 50 ° C.
Performed in a room conditioned to% RH. At this time, the longest non-contact conveyance length in the heat development processor was 18 cm. Table 2 shows the transport speed of the heat development processor. (Gamma γ) The gradient of the straight line connecting the densities 0.3 and 3.0 of the characteristic curve with respect to the horizontal axis was defined as the gradation (γ) representing the break of the leg. (Dmax) The optical density of the highest density portion of the obtained image was measured with a densitometer, and was defined as Dmax. (Adhesiveness) Cellotape (registered trademark) was pasted on the film, scratches were made on a grid, and the area ratio of the part peeled off after the tape was peeled was evaluated.

5 Peeled part 0% 4 Peeled part 1-33% 3 Peeled part 34-66% 2 Peeled part 67% -99% 1 Peeled part 100% (Generation of powder during heat development) At the time of heat development The occurrence of powder drop was visually evaluated, and 5 levels were evaluated with 5 being the best level and 1 being the worst level. (Occurrence of Burning Blurring During Baking of PS Plate) The occurrence of burning blur during baking of the PS plate was visually evaluated. Five levels were evaluated with 5 being the best level and 1 being the worst level.

Table 2 shows the results.

[0171]

[Table 1]

[0172]

[Table 2]

Ratio * 1: Ratio (%) of cellulose ester or acrylic resin having a hydroxyl group content of 4 to 20% by mass relative to the total binder mass in the image recording layer. Ratio * 2: All binders in the image recording protective layer. The ratio of the cellulose ester having a hydroxyl group content of 4 to 20% by mass based on the mass (%) In Table 1, the meanings of the symbols in the columns of "Binder 1" and "Binder 2" are as follows. % Indicates mass%. A: Cellulose acetate butyrate (hydroxyl group content: 1.8%) Tg = 141 ° C. B: Cellulose acetate propionate (hydroxyl group content: 5.0%) Tg = 159 ° C. C: Cellulose acetate butyrate ( Hydroxyl group content: 4.8%) Tg = 136 ° C. D: Cellulose acetate propionate (hydroxyl group content: 1.3%) Tg = 147 ° C. E: —SO ₃ Na-containing acrylic resin (2-hydroxyethyl) Methacrylate / methyl methacrylate = 25 /
75 (mol%), Tg = 70 ° C.) F: polymethyl methacrylate Tg: value determined by differential scanning calorimetry (DSC).

[0174]

According to the present invention, the adhesiveness is excellent, the generation of powder dropout during the heat development processing is suppressed well, the bokeh does not occur during the baking of the PS plate, and the high contrast with excellent small point reproducibility is obtained. And a photothermographic material having a high Dmax can be obtained.

Claims (9)

[Claims] 1. An organic silver salt, a silver halide,
In a heat-developable recording material having an image recording layer containing a binder and a reducing agent, an image recording protective layer is provided on the image recording layer, and a part of the binder is provided on the image recording layer and / or the image recording protective layer. A photothermographic material comprising a cellulose ester having a hydroxyl group content of 4 to 20% by mass. 2. An image recording layer having a hydroxyl group content of 4
2. The photothermographic material according to claim 1, wherein the photothermographic material contains a cellulose ester in an amount of 5 to 50% by mass based on the total binder mass of the image recording layer. 3. The image recording protective layer contains a cellulose ester having a hydroxyl group content of 4 to 20% by mass in a ratio of 5 to 50% by mass based on the total binder mass of the image recording protective layer. The photothermographic material according to claim 1, 4. The image recording layer having a hydroxyl group content of 4
The image recording protective layer contains a cellulose ester having a hydroxyl group content of 4 to 20% by mass in a content of 10 to 70% by mass of the binder in the layer. The photothermographic material according to claim 1, wherein the photothermographic material is contained. 5. The image recording protective layer contains a resin (A) having a hydroxyl group content of 0.5 to 3% by mass and a resin (B) having a hydroxyl group content of 4 to 20% by mass. )
The photothermographic material according to any one of claims 1 to 4, wherein the mass ratio of the resin / (B) is 95/5 to 50/50. 6. The photothermographic material according to claim 1, wherein the image recording layer contains an acrylic resin. 7. The photothermographic material according to claim 1, further comprising an undercoat layer containing an acrylic resin and / or polyester between the support and the image recording layer. 8. 50% by mass of the total binder in the image recording layer
The photothermographic material according to any one of claims 1 to 5, wherein the photothermographic material comprises a polymer latex, and 30% by mass or more of a solvent of the coating solution for the image recording layer is water. 9. The photothermographic material according to claim 1, wherein a conveying speed of the photothermographic machine is 22 mm / sec.
A method for processing a photothermographic material, wherein heat development is performed at c to 40 mm / sec.