JP2000131792A - Heat developable photographic sensitive material, its production and image forming method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To improve adhesivity between the substrate of a heat developable photographic sensitive material and constituent layers (a photosensitive layer, a back coat layer, etc.), and adhesivity between constituent layers (the photosensitive layer and a protective layer, etc.), to produce a heat developable photographic sensitive material which forms a good image with reduced fog density and without sensitivity reduction and to provide an image forming method by which a good image is formed. SOLUTION: The heat developable photographic sensitive material has a) a photosensitive layer containing an organic silver salt, a silver halide and a reducing agent on one side of the substrate, b) a layer situated farther from the substrate than the photosensitive layer and c) at least one layer disposed on the other side of the substrate. Each of the layers contains polyester and at least one of the layers is heat treated after coating.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a heat-developable photographic light-sensitive material, and more particularly to a black-and-white heat-developable photographic light-sensitive material, a method for producing the same, and an image forming method.

[0002]

2. Description of the Related Art Conventionally, in the field of printing plate making and medical treatment, a waste liquid caused by wet processing of an image forming material has been a problem in terms of workability. Weight loss is strongly desired. Therefore, there has been a need for a technique relating to photothermographic materials for photographic technology, which enables efficient exposure with a laser imagesetter or laser imager and can form a high-resolution, clear black image.

As a technique for this purpose, a heat-developable photographic light-sensitive material for forming a photographic image by using a heat-development processing method is disclosed in, for example, US Pat.
No. and D. Morgan and B.A. Shelly Processed Sil by Shelly
ver Systems) "(Imaging Pr. and Materials (Imaging Pr.)
processes and Materials) Ne
blette 8th edition, Sturge,
V. Walworth, A .; Shepp, page 2, 1969).

Polyvinyl butyral (hereinafter abbreviated as PVB) as a binder for a photosensitive layer of a photothermographic material, and cellulose acetate butyrate as a binder for a back coat layer provided on a side opposite to the photosensitive layer with a protective layer and a support interposed therebetween. It is known to use polyethylene terephthalate (hereinafter abbreviated as PET) as a support and a support (hereinafter abbreviated as CAB). For example, JP-A-51-104338 and JP-A-5-120715 describe these examples. However, this photosensitive material does not have sufficient adhesion between the support and the photosensitive layer coated thereon, and between the support and the back coat layer, and the photosensitive layer and the back coat layer are separated from the support during use of the photosensitive material. It had the disadvantage of peeling.

There is known a technique of providing an undercoat layer between a photosensitive layer or a back coat layer and a support for the purpose of improving the adhesive strength to the support. For example, JP-A-55-93149 describes an example of a photosensitive material provided with a subbing layer of a vinyl chloride-vinyl acetate copolymer. However, such an undercoat layer does not sufficiently solve the above-described problem, and a heat-developable photographic material having good adhesion between the support and the photosensitive layer or between the support and the back coat layer is desired. Was rare.

In the production of a photothermographic material, a coating solution obtained by dissolving or dispersing a coating solution composition containing the above-mentioned binder in an organic solvent is coated on a support, and then blown with hot air. It is obtained by forming each constituent layer (photosensitive layer, protective layer, back coat layer, etc.) by repeating drying.

However, the heat-developable photographic material obtained by employing such a manufacturing method has a problem that the adhesiveness between the layers is deteriorated. This problem was solved by adjusting the amount of solvent in the coating solution.However, especially for the photosensitive layer, increasing the amount of solvent increases the fog density, and decreasing the amount of solvent causes a decrease in sensitivity. A new problem has arisen.

[0008]

DISCLOSURE OF THE INVENTION The present invention has been made in view of the above circumstances, and has as its object the purpose of providing a support between a support and constituent layers (photosensitive layer, back coat layer) of a photothermographic material.
Another object is to improve the adhesiveness between the constituent layers (photosensitive layer, protective layer, etc.). The second purpose is to reduce fog density,
An object of the present invention is to provide a heat-developable photographic light-sensitive material capable of forming a good image without lowering the sensitivity. Another object of the present invention is to provide a method of manufacturing the same and an image forming method capable of forming a good image.

[0009]

The above objects of the present invention have been attained by the following constitutions.

1) a) a photosensitive layer containing organic silver, silver halide and a reducing agent on a support; and b) a layer provided on a side farther than the photosensitive layer with respect to the support, c) In a photothermographic material having at least one layer provided on the side opposite to the side having the photosensitive layer with a support interposed therebetween, each layer contains polyester, and at least one side is coated and heat-treated. A heat-developable photographic material characterized by being formed in the following order:

2) The photothermographic material according to 1), wherein the layer b) is provided on the photosensitive layer before the residual amount of the solvent in the photosensitive layer becomes 70% by weight or less.

3) The total amount of the solvent in all the layers of the photothermographic material after the heat treatment is from 30 to 50 per m ^{2 of the} photographic material.
The photothermographic material according to 1) or 2), which is 0 mg.

4) On a support, a) a photosensitive layer containing organic silver, silver halide and a reducing agent; and b) a layer provided on a side farther than the photosensitive layer from the support, c) In producing a photothermographic material having at least one layer provided on the side opposite to the side having the photosensitive layer with the support interposed therebetween, and wherein each of the layers contains polyester,
A method for producing a photothermographic material, wherein at least one of the constituent layers is formed by heat treatment after coating.

5) The photothermographic method according to 4), further comprising the step of providing the layer b) on the photosensitive layer before the residual amount of the solvent in the photosensitive layer becomes 70% by weight or less. Material manufacturing method.

6) An image forming method, wherein the photothermographic material according to any one of 1) to 3) is exposed and then developed by a heat treatment at 80 to 200 ° C.

That is, the purpose of the present invention is to reduce the adhesiveness between the support and the photosensitive layer or between the support and the back coat layer when the photothermographic material (hereinafter simply referred to as "photosensitive material") is used. The problem of delamination
Each constituent layer, or each constituent layer-paying attention to the adhesiveness between the support, characterized by being able to improve and improve these, containing polyester as a binder in all constituent layers, And after applying the constituent layer coating solution, it is possible to expect further adhesiveness by performing a heat treatment and drying.
As a result, they have found that the occurrence of delamination can also be suppressed, and the present invention has been accomplished.

In particular, when the target constituent layer is a photosensitive layer and a protective layer for the photosensitive layer, if the simultaneous multi-layer coating is performed, the interface between the layers is disturbed to cause diffusion of substances, and the polyester layer interface in the layer is caused. The effect that the adhesion in the is strengthened is obtained,
In addition, when an antifoggant is added to the protective layer, an additional effect of preventing fog in the photosensitive layer can be obtained.

When PET is used as the support, a strong relationship is formed with the polyester in the photosensitive layer, and the adhesion between the support and the photosensitive layer is improved. A similar relationship is formed between the support and the back coat layer, whereby the adhesion between the support and the back coat layer can be improved, and the problem of delamination of the back coat layer can be improved.

On the other hand, the problem that the fog density is increased or the sensitivity is lowered depending on the amount of the solvent used is considered as the total amount of all the layers after the simultaneous multi-layer coating and the heat treatment, that is, the residual solvent of the photosensitive material. The present inventors have found that the amount can be improved by performing processing to obtain an optimal value, and have reached the present invention.

Hereinafter, the present invention will be described in detail.

[1] Photothermographic Material The photothermographic material of the present invention comprises, on a support, a) a photosensitive layer containing organic silver, silver halide and a reducing agent (hereinafter referred to as a "photosensitive layer").
B) a layer (hereinafter simply referred to as a protective layer) provided on a side farther than the photosensitive layer with respect to the support, and c) a side having the photosensitive layer with the support interposed therebetween. Has at least one layer provided on the opposite side (hereinafter simply referred to as a back coat layer), wherein each of the layers contains polyester, and at least one side is formed in the order of application and heat treatment It is characterized by.

(Polyester) As the polyester used as the binder,-(O-C
O) -Polymer having a structure, which is usually obtained by a condensation reaction of a polycarboxylic acid and a polyhydric alcohol.

Examples of the polycarboxylic acid include phthalic acid, phthalic anhydride, isophthalic acid, tetrahydrophthalic acid, adipic acid, sebacic acid, thiodiglycolic acid, 3,6-endomethylenetetrahydrophthalic acid, and tetrachlorophthalic anhydride. , 3,6-endodichloromethylenetetrachlorophthalic acid, etc .; unsaturated dibasic acids such as maleic acid, maleic anhydride, fumaric acid, mesaconic acid, citraconic acid, itaconic acid, chlorinated maleic acid, etc. And polybasic acids such as pyromelic acid, pyromelic acid anhydride and trimeric acid.

Examples of the polyhydric alcohol include ethylene glycol, diethylene glycol, 1,2-propylene glycol, dipropylene glycol, 1,3-butylene glycol, 2,3-butylene glycol, bisphenoldioxyethylene ether and bisphenoldioxypropylene ether. , Neopentyl glycol, 1,4
-Butenediol and the like.

The polyester may be a "saturated polyester" containing no double bond in the molecular main chain or an "unsaturated polyester" containing a double bond in the main chain. Further, it may have a linear structure or a branched structure.

The polyester used in the present invention may be a polyester alone or a copolymer with another polymer. However, the term “copolymerization” used herein includes not only a polymer containing a polyester structure and another polymer structure in the main chain, but also a polymer in which another polymer is graft-polymerized on a side chain of the polyester main chain.

Any of these polyesters may be used as long as they can be dissolved in ordinary organic solvents. The molecular weight of the polyester used in the present invention is preferably from 1,000 to 50,000, more preferably from 5,000 to 20,000. Those having a molecular weight of less than 1,000 are unsuitable because the film strength is too small. Those having an extremely high molecular weight may be difficult to apply because the solubility in a solvent is too small. Also, the crystal of the polyester is not particularly limited, but the smaller the crystallinity, the better the solubility in a solvent and the easier the coating.

Specific examples of the polyester used in the present invention include the following.

[0029]

Embedded image

The following commercially available polyesters can also be used.

Byron 103, 200, 300, 50
0, 30P, GM400, GM900, GV100, G
V900 (manufactured by Toyobo Co., Ltd.) WD-size, WMS, WNT (manufactured by Eastman Chemical Co., Ltd.) FINITEX ES525, 611, 650, 67
5,679,801,850 (manufactured by Dainippon Ink and Chemicals, Inc.) In the constituent layer containing the polyester used in the present invention, the polyester contains 2% by weight or more, preferably 5% by weight or more of the total binder. It is desirable to be included. If the polyester content is too small, the effect of improving the adhesion is small. The polyester contained in the constituent layer may be one kind or a plurality of kinds.

In the present invention, a desired effect is exhibited by heat-treating the constituent layer containing the polyester as a binder as described above.

In the present invention, the term "heat treatment" means that a coating solution for a constituent layer (photosensitive layer, protective layer, undercoat layer, back coat layer, etc.) is applied to a support, dried, and then the polyester glass is coated. Heating at a temperature higher than the transition point (Tg) is followed by cooling to room temperature.

In the present invention, it is preferable that the protective layer is applied on the photosensitive layer before the remaining amount of the total solvent in the photosensitive layer becomes 70% by weight or less. The remaining amount of all solvents in the photosensitive layer is 7
When the amount is less than 0% by weight, the photosensitive layer and the protective layer are completely separated from each other, and there is a high possibility that the effects of the present invention cannot be obtained.

In the heat-developable photographic light-sensitive material of the present invention, the total amount of the solvent in all the constituent layers after coating and heat treatment is preferably 30 to 500 mg / m ^{2 of the} light-sensitive material, and more preferably photographic light-sensitive material. material 1m ² per 30 to 200
mg. As described above, the processing is performed so that the total amount of the solvent in all the constituent layers of the photosensitive material after the heat treatment, that is, the amount of the remaining solvent in the photosensitive material becomes an optimum value, thereby reducing the fog density and preventing the sensitivity from decreasing. The effect of the present invention that a good image can be formed is exhibited.

In the present invention, the preferable thickness (after drying) of the photosensitive layer is 0.2 to 40 μm, more preferably 2 to 30 μm per layer. The preferred thickness of the protective layer is 0.2 to 10 μm per layer, more preferably 1 to 10 μm.
5 μm. Similarly, the preferred thickness of the BC (backcoat) layer is 0.2 to 10 μm, more preferably 1 to 5 μm per layer.

(Silver Halide) The silver halide in the present invention functions as an optical sensor. In the present invention, in order to suppress white turbidity after image formation and to obtain good image quality, it is preferable that the average grain size of silver halide is small, and the average grain size is 0.1 μm or less, more preferably 0.01 μm to 0.1 μm, particularly preferably 0.02 μm to 0.08 μm. The term "grain size" as used herein refers to the length of a ridge of a silver halide grain when the silver halide grain is a cubic or octahedral so-called normal crystal. If the crystal is not normal, for example, spherical,
In the case of rod-shaped or tabular grains, it refers to the diameter of a sphere equivalent to the volume of silver halide grains. The silver halide is preferably monodispersed. Here, the monodispersion means that the degree of monodispersion determined by the following formula is 40% or less. The particles are more preferably 30% or less, particularly preferably 0.1% or more and 20% or less.

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

The shape of the silver halide grains is not particularly limited, but it is preferable that the ratio occupied by the Miller index [100] plane is high, and this ratio is 50% or more, and more preferably 7%.
It is preferably at least 0%, particularly preferably at least 80%. The ratio of the Miller index [100] plane is determined by the T.M. Tani, J .; Imaging Sci. , 29,
165 (1985).

Another preferred form of silver halide is tabular grains. The term “tabular grains” as used herein means a vertical thickness hμ where the square root of the projected area is a particle diameter rμm.
The aspect ratio when r = r / h is 3 or more. Among them, the aspect ratio is preferably 3 or more and 50 or less. The particle size is preferably 0.1 μm or less, and more preferably 0.01 μm to 0.08 μm. These are disclosed in U.S. Patent Nos. 5,264,337, 5,314,
No. 798, 5,320,958, etc., and the desired tabular grains can be easily obtained. When these tabular grains are used in the present invention, the sharpness of an image is further improved.

The halogen composition is not particularly limited, and may be any of silver chloride, silver chlorobromide, silver chloroiodobromide, silver bromide, silver iodobromide and silver iodide. The photographic emulsion used in the present invention is P.I. Chimie et by Glafkids
Physique Photographique (P
aul Montel, 1967); F. D
Photographic Emuls by uffin
ion Chemistry (The Focal P
Res., 1966); L. Zelikman
Making and Coating by et al
Photographic Emulsion (Th
e Focal Press, 1964) and the like. That is, any of an acidic method, a neutral method, an ammonia method, etc. may be used.
Any of a one-side mixing method, a simultaneous mixing method, a combination thereof and the like may be used. The silver halide may be added to the image forming layer by any method, in which case the silver halide is arranged close to the reducible silver source. Further, the silver halide may be prepared by converting a part or all of the silver in the organic acid silver by the reaction of the organic acid silver and the halogen ion into silver halide, or may be prepared by preparing silver halide in advance. In advance, this may be added to a solution for preparing an organic silver salt, or a combination of these methods is possible, but the latter is preferred. Generally, the silver halide is preferably contained in an amount of 0.75 to 30% by weight based on the organic silver salt.

The silver halide used in the present invention preferably contains metal ions belonging to groups 6 to 11 of the periodic table. As the above metals, W, Fe, Co,
Ni, Cu, Ru, Rh, Pd, Re, Os, Ir, P
t and Au are preferred.

These metal ions can be introduced into silver halide in the form of a metal complex or a metal complex ion. As these metal complexes or metal complex ions, hexacoordinate metal complexes represented by the following general formula are preferable.

In the general formula [ML ₆ ] ^m , M is a transition metal selected from elements of Groups 6 to 11 of the periodic table, L is a ligand, and m is 0,-, 2-, 3- or 4-
Represents Specific examples of the ligand represented by L include halides (fluoride, chloride, bromide and iodide), cyanide, cyanate, thiocyanate, selenocyanate, tellurocyanate, azide and aquo. Ligand, nitrosyl, thionitrosyl and the like, preferably aquo, nitrosyl and thionitrosyl. If an aquo ligand is present, it preferably occupies one or two of the ligands. L may be the same or different.

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

Specific examples of transition metal complex ions are shown below, but the present invention is not limited to these.

[0047] 1: [RhCl _6] ^3- 2: [RuCl _6] ^3- 3: [ReCl _6] ^3- 4: [RuBr _6] ^3- 5: [OsCl _6] ^3- 6: [IrCl _6] ^{4 -} 7: [Ru (NO) Cl _5] ^2- 8: [RuBr ₄ (H ₂ O)] ^2- 9: _{[Ru (NO) (H 2 O} ) Cl 4 ] ^- 10: [RhCl ₅ (H ₂ O)] ^2- 11: [Re (NO) Cl _5] ^2- 12: [Re (NO) CN _5] ^2- 13: [Re (NO) ClCN _4] ^2- 14: [Rh (NO) ₂ Cl _4] ^- 15: _{[Rh (NO) (H 2 O} ) Cl 4 ] ^- 16: [Ru (NO) CN _5] ^2- 17: [Fe (CN) _6] ^3- 18: [Rh (NS) Cl _5] ^2- 19: [Os (NO) Cl _5] ^2- 20: [Cr (NO) Cl _5] ^2- 21: [Re (NO) Cl _5] ^- 22: [Os (NS) Cl ₄ (TeCN )] ^2- 23: Ru (NS) Cl _5] ^2- 24: _{[Re (NS) Cl 4 (SeCN} ) ] ^2- 25: [Os (NS) Cl (SCN) 4 ] ^2- 26: [Ir (NO) Cl _5] ^{2 -} 27: [Ir (NS) Cl _5] ^2- these metal ions may be a metal complex or metal complex ions one type, the metal of the same kind of metal or different may be used alone or in combination. The content of these metal ions, metal complexes or metal complex ions, generally is suitably 1 × 10 ^-9 ~1 × 10 ^-2 mol per mol of silver halide, preferably 1 × 10 ^{- It is 8} to 1 × 10 ^-4 mol.

The compounds providing these metals are preferably added during silver halide grain formation and incorporated into silver halide grains. Preparation of silver halide grains, that is, nucleation, growth, physical ripening, and chemical ripening Although it may be added at any stage before and after sensitization, it is particularly preferable to add at the stage of nucleation, growth and physical ripening, more preferably at the stage of nucleation and growth, and most preferably. It is added at the stage of nucleation.

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

These metal compounds can be added by dissolving in water or a suitable organic solvent (eg, alcohols, ethers, glycols, ketones, esters, amides). A method in which an aqueous solution of a powder or an aqueous solution in which a metal compound and NaCl and KCl are dissolved together is added to a water-soluble silver salt solution or a water-soluble halide solution during grain formation, or a silver salt solution and a halide solution are used. When they are mixed simultaneously, they are added as a third aqueous solution to prepare silver halide grains by a three-liquid simultaneous mixing method, a method in which a required amount of an aqueous solution of a metal compound is charged into a reaction vessel during grain formation, or a method in which halogen is added. There is a method in which another silver halide grain doped with metal ions or complex ions in advance during the preparation of silver halide is added and dissolved. In particular, a method of adding an aqueous solution of a powder of a metal compound or an aqueous solution in which a metal compound and NaCl and KCl are dissolved together is added to a water-soluble halide solution.

When adding to the particle surface, a necessary amount of an aqueous solution of a metal compound can be charged into the reaction vessel immediately after the formation of the particles, during or during the physical ripening, or at the time of chemical ripening.

The photosensitive silver halide grains can be desalted by washing with a method known in the art such as a noodle method or a flocculation method, but in the present invention, desalting is not required. Is also good.

The photosensitive silver halide grains in the present invention are preferably chemically sensitized. Preferred chemical sensitization methods are sulfur sensitization, selenium sensitization, tellurium sensitization, noble metal sensitization such as gold compounds, platinum, palladium, and iridium compounds, and reduction sensitization as well known in the art. Sensitization can be used. Known compounds can be used as compounds preferably used in the sulfur sensitization method, the selenium sensitization method, and the tellurium sensitization method.
Compounds described in No. 8768 and the like can be used.
Compounds preferably used in the noble metal sensitization method include, for example, chloroauric acid, potassium chloroaurate, potassium aurithiocyanate, gold sulfide, gold selenide, US Pat. No. 2,448,060, and British Patent 618,06.
The compounds described in No. 1 and the like can be preferably used. As specific compounds of the reduction sensitization method, in addition to ascorbic acid and thiourea dioxide, for example, stannous chloride, aminoiminomethanesulfinic acid, hydrazine derivatives, borane compounds, silane compounds, polyamine compounds and the like can be used. . When the pH of the emulsion is 7 or more or p
Reduction sensitization can be achieved by ripening while keeping Ag at 8.3 or less. Further, reduction sensitization can be achieved by introducing a single addition portion of silver ions during grain formation.

(Organic silver) In the present invention, organic silver (hereinafter, referred to as organic silver)
Organic silver salts) are reducible silver sources, and silver salts of organic acids and heteroorganic acids containing a reducible silver ion source,
Particularly, a long-chain (10 to 30, preferably 15 to 25, carbon atoms) aliphatic carboxylic acid and a nitrogen-containing heterocyclic ring are preferred. Organic or inorganic silver salt complexes wherein the ligand has a total stability constant for silver ions of 4.0 to 10.0 are also useful. An example of a suitable silver salt is Research Discl
osure (hereinafter referred to as RD) Nos. 17029 and 29
963, and include the following: salts of organic acids (eg, salts of gallic acid, oxalic acid, behenic acid, arachidic acid, stearic acid, palmitic acid, lauric acid, etc.); silver carboxyalkylthioureas Salt (for example, 1
-(3-carboxypropyl) thiourea, 1- (3-carboxypropyl) -3,3-dimethylthiourea, etc.);
Silver complexes of polymer reaction products of aldehydes and hydroxy-substituted aromatic carboxylic acids (eg, aldehydes (formaldehyde, acetaldehyde, butyraldehyde, etc.), hydroxy-substituted acids (eg, salicylic acid, benzoic acid, 3,5-dihydroxybenzoic acid) , 5,5-thiodisalicylic acid)), silver salts or complexes of thioenes (e.g.,
3- (2-carboxyethyl) -4-hydroxymethyl-4- (thiazoline-2-thioene and 3-carboxymethyl-4-thiazoline-2-thioene), imidazole, pyrazole, urazole, 1,2,4- Complexes or salts of silver with a nitrogen acid selected from thiazole and 1H-tetrazole, 3-amino-5-benzylthio-1,2,4-triazole and benzotriazole; silver salts such as saccharin and 5-chlorosalicylaldoxime And silver salts of mercaptides. Of these, preferred silver sources are silver behenate, arachidic acid and / or stearic acid.

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

In the present invention, the organic silver salt has an average particle size of 2 μm.
m or less and monodisperse. The average particle size of the organic silver salt refers to the diameter of a sphere equivalent to the volume of the organic silver salt particles when the particles of the organic silver salt are, for example, spherical, rod-shaped, or tabular particles. The average particle size is preferably 0.05 μm to 1.5 μm, particularly 0.05 μm
~ 1.0 µm is preferred. The monodispersion has the same meaning as in the case of silver halide, and preferably has a monodispersity of 1 to 30. Further, in the organic silver salt of the present invention, it is preferable that 60% or more of the total organic silver salt is tabular grains. In the present invention, the tabular grains mean those having an aspect ratio (abbreviated as AR) of 3 or more, which is a ratio between the average particle diameter and the thickness, that is, the so-called following formula.

AR = average particle size (μm) / thickness (μm) In order to form the organic silver salt into these shapes, the organic silver crystal is dispersed and pulverized together with a binder, a surfactant and the like by a ball mill or the like. can get. Within this range, a photosensitive material having a high density and excellent image storability can be obtained.

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

(Reducing Agent) The photosensitive layer of the photothermographic material of the present invention contains a reducing agent. Examples of suitable reducing agents are described in U.S. Patent Nos. 3,770,448 and 3,773.
No. 3,512, No. 3,593,863, and RD1
7029 and 29996, and include the following.

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

(Binder) In addition to the polyesters described above, binders suitable for the heat-developable photographic light-sensitive material of the present invention are transparent or translucent, generally colorless, and form natural polymer synthetic resins, polymers and copolymers, and other films. Media such as: gelatin, gum arabic,
Poly (vinyl alcohol), hydroxyethyl cellulose, cellulose acetate, cellulose acetate butyrate, poly (vinyl pyrrolidone), casein, starch, poly (acrylic acid), poly (methyl methacrylic acid), poly (vinyl chloride), poly (methacrylic acid) ), Copoly (styrene-maleic anhydride), copoly (styrene-acrylonitrile), copoly (styrene-butadiene), poly (vinylacetal) s (eg, poly (vinylformal)), poly (ester) s, poly (urethane) ), Phenoxy resin, poly (vinylidene chloride),
Poly (epoxides), poly (carbonates), poly (vinyl acetate), cellulose esters, and poly (amides) can be used. Although it may be hydrophilic or hydrophobic, in the present invention, it is preferable to use a hydrophobic transparent binder in order to reduce fog after thermal development. Preferred binders include polyvinyl butyral, cellulose acetate, cellulose acetate butyrate, polyester, polycarbonate, polyacrylic acid, polyurethane and the like. Among them, polyvinyl butyral, cellulose acetate, cellulose acetate butyrate, and polyester are particularly preferably used.

Further, a protective light layer is provided outside the photosensitive layer to protect the surface of the photosensitive material and to prevent abrasion. The binder used for these may be the same or different from the binder used for the photosensitive layer. Good.

In the present invention, the amount of the binder in the photosensitive layer is preferably 1.5 to 10 g / m ² in order to increase the speed of thermal development. More preferably, 1.7 to 8 g / m
² If it is less than 1.5 g / m ² , the density of the unexposed portion will increase significantly and may not be usable.

(Matting Agent) In the present invention, a matting agent is preferably contained on the photosensitive layer side, and a matting agent is disposed on the surface of the photosensitive material in order to prevent the image after thermal development from being damaged. It is preferable that the matting agent is contained in a weight ratio of 0.5 to 30% based on all binders on the photosensitive layer side. When a back coat layer is provided on the surface opposite to the photosensitive layer with the support interposed therebetween, it is preferable that at least one layer on the back coat layer side contains a matting agent, and that the photosensitive material has slipperiness and fingerprint adhesion. For prevention, it is preferable to provide a matting agent on the surface of the photosensitive material, and the matting agent is contained in a weight ratio of 0.5 to 40% with respect to all binders in the layer on the side opposite to the photosensitive layer side. preferable.

The material of the matting agent used in the present invention may be either an organic substance or an inorganic substance. For example, as inorganic substances, silica described in Swiss Patent No. 330,158, glass powder described in French Patent No. 1,296,995, etc., and alkaline earth described in British Patent No. 1,173,181 etc. Metals or carbonates such as cadmium and zinc can be used as the matting agent. Examples of organic substances include starch described in U.S. Pat. No. 2,322,037, Belgian Patent No. 625,451, and British Patent No. 981,198.
And polyvinyl alcohol described in JP-B-44-3643 and the like, and Swiss Patent No. 33.
No. 0,158, polystyrene or polymethacrylate; U.S. Pat. No. 3,079,257; polyacrylonitrile; U.S. Pat. No. 3,022,16.
An organic matting agent such as polycarbonate described in No. 9 or the like can be used.

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

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

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

(Standard deviation of particle size) / (average value of particle size) × 100 The matting agent according to the present invention can be contained in any constituent layer, but is preferably used in order to achieve the object of the present invention. Is a constituent layer other than the photosensitive layer, and is more preferably the outermost layer as viewed from the support.

The method of adding the matting agent according to the present invention may be a method of dispersing in a coating solution in advance and applying the solution.
A method of spraying a matting agent after the application liquid is applied and before the drying is completed may be used. When a plurality of types of matting agents are added, both methods may be used in combination.

(Other Additives) The back coat layer may contain an antihalation dye or pigment. As the dye to be used, any compound may be used as long as it has a desired absorption in a desired wavelength range. For example, JP-A-59-6481 and JP-A-59-182436, U.S. Pat. 4,594,312
No., European Patent Publication Nos. 533008, 652473,
Compounds described in JP-A-2-216140, JP-A-4-348339, JP-A-7-191432 and JP-A-7-301890 are preferably used. The optical density (absorbance unit at λmax of the dye) of these dyes is 0.05 to 3.
It is preferably incorporated in an amount sufficient to obtain 0, especially 0.1 to 2.0. The coating weight of the dye is generally 0.001
１1 g / m ² , preferably 0.001 to 0.05 g / m ²
It is.

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

The heat-developable photographic light-sensitive material of the present invention forms a photographic image by heat-development processing, and comprises a reducible silver source (organic silver salt), a photosensitive silver halide, a reducing agent and, if necessary, It is preferable that the color tone agent which suppresses the color tone of silver is usually contained in a dispersed state in an (organic) binder matrix. The photothermographic material of the present invention is stable at room temperature, but is developed by heating to a high temperature (for example, 80 ° C to 140 ° C) after exposure. Heating generates silver through an oxidation-reduction reaction between an organic silver salt (functioning as an oxidizing agent) and a reducing agent. This oxidation-reduction reaction is accelerated by the catalytic action of the latent image generated on the silver halide upon exposure. The silver formed by the reaction of the organic silver salt in the exposed areas provides a black image, which contrasts with the unexposed areas, resulting in the formation of an image. This reaction process proceeds without supplying a processing liquid such as water from the outside.

Examples of suitable toning agents used in the present invention are R
D17029 discloses the following.

Imides (eg phthalimide); cyclic imides, pyrazolin-5-ones, and quinazolinones (eg succinimide, 3-phenyl-2-pyrazolin-5-one, 1-phenylurazole, quinazoline and , 4-thiazolidinedione); naphthalimides (eg, N-hydroxy-1,8-naphthalimide); cobalt complexes (eg, hexamine trifluoroacetate of cobalt), mercaptans (eg, 3
-Mercapto-1,2,4-triazole); N- (aminomethyl) aryldicarboximides (for example,
N- (dimethylaminomethyl) phthalimide); blocked pyrazoles, isothiuronium (isoth
uronium) derivatives and certain photobleaching combinations (eg, N, N'-hexamethylene (1-carbamoyl-3,5-dimethylpyrazole), 1,8-
A combination of (3,6-dioxaoctane) bis (isothiuronium trifluoroacetate) and 2- (tribromomethylsulfonyl) benzothiazole; a merocyanine dye (e.g., 3-ethyl-5-((3-ethyl -2-benzothiazolinylidene (benzothiazolinylidene))-1-methylethylidene) -2-thio-2,4
-Oxazolidinedione); phthalazinone, a phthalazinone derivative or a metal salt of these derivatives (for example, 4-
(1-naphthyl) phthalazinone, 6-chlorophthalazinone, 5,7-dimethyloxyphthalazinone, and 2,3
-Dihydro-1,4-phthalazinedione); a combination of phthalazinone and a sulfinic acid derivative (for example, 6-chlorophthalazinone + sodium benzenesulfinate or 8-methylphthalazinone + sodium p-trisulfonate); phthalazine + phthalate Acid combinations; phthalazine (including phthalazine adducts) and maleic anhydride,
And phthalic acid, 2,3-naphthalenedicarboxylic acid or o
At least one selected from phenylene acid derivatives and anhydrides thereof (for example, phthalic acid, 4-methylphthalic acid, 4-nitrophthalic acid and tetrachlorophthalic anhydride);
Quinazolinediones, benzoxazines, naloxazine derivatives; benzoxazine-2,4-diones (eg, 1,3-benzoxazine-2,4-dione); pyrimidines and asymmetric triazines (E.g., 2,4-dihydroxypyrimidine) and tetraazapentalene derivatives (e.g., 3,
6-dimercapto-1,4-diphenyl-1H, 4H-
2,3a, 5,6a-tetraazapentalene). Of these, phthalazone or phthalazine is preferred as a color tone agent.

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

The photothermographic material of the present invention may contain an antifoggant. Mercury compounds known as effective antifoggants, for example, in US Pat. No. 3,589,903, are environmentally unfavorable. Therefore, non-mercury antifoggants have been studied for a long time. Non-mercury antifoggants include, for example, U.S. Pat. No. 4,546,075.
No. 4,452,885 and JP-A-59-57.
Preferred are antifoggants as disclosed in US Pat.

Particularly preferred non-mercury antifoggants are US Pat. Nos. 3,874,946 and 4,756,993.
No.9, -C (X ₁ )
(X ₂ ) (X ₃ ) wherein X ₁ and X ₂ are halogen;
X ₃ is a heterocyclic compound having one or more substituents represented by hydrogen or halogen). Examples of suitable antifoggants are described in JP-A-9-288328, paragraph [00
Compounds described in [30] to [0036] are preferably used. As another example of a preferred antifoggant, JP-A-9-90550, paragraph [006]
2] to [0063]. Still other suitable antifoggants are disclosed in U.S. Pat.
8,523 and UK Patent Application No. 9221383.4.
No. 9300147.7 and No. 9311790.
No. 1.

A sensitizing dye can be used in the photothermographic material of the present invention. Useful sensitizing dyes for use in the present invention are described, for example, in RD17643 IV-A (p.2 December 1978, p.2).
3), Item 1831X (August 1978, p. 4
37) or in the literature cited. In particular, a sensitizing dye having a spectral sensitivity suitable for the spectral characteristics of various scanner light sources can be advantageously selected. For example, compounds described in JP-A-9-34078, JP-A-9-54409 and JP-A-9-80679 are preferably used.

Various additives may be added to any of the photosensitive layer, the protective layer and the back coat layer. The photothermographic material of the present invention includes, for example, anionic, nonionic, cationic surfactants, isocyanate-based, epoxy-based crosslinking agents, silicones, sliding agents such as paraffin,
Fillers such as colloidal silica, antioxidants, stabilizers, plasticizers, ultraviolet absorbers, coating aids, and the like may be used. These additives and the other additives mentioned above are RD
17029 (pp. 9-15, June 1978) can be preferably used.

(Support) The support used in the present invention is a plastic film (for example, polyethylene terephthalate (PET),
Polycarbonate, polyimide, nylon, cellulose triacetate, polyethylene naphthalate) are preferred. The support may have been subjected to surface treatment or undercoating. Preferable examples of the binder for the undercoat layer include those obtained by arbitrarily mixing polyvinyl butyral and cellulose acetate butyrate, polyester resins, and urethane resins. The thickness of the support is 50 to 300
It is about μm, preferably 70 to 180 μm. Further, those obtained by heat-treating the above-mentioned plastics can also be used. The heat treatment of the support means that after forming the support, before the photosensitive layer is coated, the support is heated to 3 ° C. from the glass transition point of the support.
The heating is performed at a temperature higher than 0 ° C., preferably at a temperature higher than 35 ° C., and more preferably at a temperature higher than 40 ° C. However, the effect of the present invention cannot be obtained by heating at a temperature exceeding the melting point of the support.

For the method of forming a support and the method of producing an undercoat according to the present invention, known methods can be used. Preferably, paragraphs [0030] to [0] of JP-A No. 9-50094 are used.
070].

Of these, biaxially stretched polyethylene terephthalate having a thickness of about 50 to 300 μm has strength,
It is a preferred support from the viewpoint of chemical resistance and the like.

In the present invention, a conductive compound such as a metal oxide and / or a conductive polymer can be contained in the constituent layer in order to improve the chargeability. These may be contained in any layer, but are preferably contained in an undercoat layer, a back coat layer, a layer between the photosensitive layer and the undercoat, and the like. In the present invention, US Pat. No. 5,244,773 column 1
The conductive compounds described in 4 to 20 are preferably used.

[2] Method for Producing Photothermographic Photosensitive Material The photothermographic material of the present invention is prepared by dissolving or dispersing the above-mentioned constituent layer materials in a solvent, and preparing a plurality of these coating solutions simultaneously. After the multi-layer coating, a heat treatment is preferably performed. Here, “multi-layer coating at the same time” means that a coating solution for each constituent layer (for example, a photosensitive layer and a protective layer) is prepared, and when the coating solution is applied to a support, coating and drying are repeated for each layer individually. In other words, it means that each constituent layer can be formed in a state where the steps of simultaneously performing the multilayer coating and drying can be performed at the same time. That is, the upper layer is provided before the remaining amount of all the solvents in the lower layer becomes 70% by weight or less.

There is no particular limitation on the method of simultaneously applying a plurality of constituent layers in a multi-layered manner. For example, known methods such as a bar coater method, a curtain coat method, a dipping method, an air knife method, a hopper coating method, and an extrusion coating method are used. Can be used. Of these, a pre-metering type coating method called an extrusion coating method is more preferable. The extrusion coating method is suitable for precision coating and organic solvent coating since there is no volatilization on the slide surface unlike the slide coating method. The extrusion coating method will be described with reference to the drawings.

FIG. 1 schematically shows an extrusion coating apparatus. The extrusion coater 1 is composed of a manifold section 2 and a slot section 3, and a negative pressure can be applied to the coating upstream side. Two slots are used to form a simultaneous multilayer. Each of the coating liquids 7 and 8 flowing out of the manifold section 2 is guided to the two slot sections and is simultaneously coated on the support 4 in a multilayer manner. At this time, since the vacuum part 5 is formed by sucking air from the suction port 6 by an external suction device (not shown), a constant multilayer coating can be performed.

In the present invention, after the simultaneous multi-layer coating is performed, a heat treatment is subsequently performed to dry the surface of the coated layer, so that the adhesiveness between the support and the photosensitive layer and between the photosensitive layer and the protective layer is reduced. And delamination is prevented from occurring.
This coating method has been described on the side having the photosensitive layer, but the same applies to the case where the backcoat layer is provided and the coating is performed together with the undercoating.

[3] Image Forming Method The image forming method of the present invention is characterized in that the photothermographic material obtained as described above is exposed and then developed by a heat treatment at 80 to 200 ° C.

In the present invention, the development conditions vary depending on the equipment, apparatus, or means used, but typically, the heat-developable photographic material exposed imagewise at a suitable high temperature is heated. Accompanies you. The latent image obtained after the exposure is exposed to a heat at a moderately high temperature (for example, about 80 to 200 ° C., preferably about 100 to 200 ° C.) for a sufficient time (generally about 1 second to about 2 minutes). The material can be developed by heating. The equipment, apparatus or means for heating may be performed by a typical heating means such as a heat generator using a hot plate, an iron, a hot roller, carbon or white titanium or the like. More preferably, it is transported while being in contact with the heat roller, heated, and developed, from the viewpoint of thermal efficiency and workability.

[0091]

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

Example 1 "Preparation of heat-developable photographic light-sensitive material"<Preparation of PET-subbed photographic support> A commercially available biaxially stretched and heat-fixed blue-colored PET film having a thickness of 175 μm and 8 w / A corona discharge treatment of m ² · min was performed.

Liquid Preparation Method for Each Constituent Layer <Photosensitive Layer> (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, and the temperature was adjusted to 35 ° C. and the pH to 3.0. After adjusting to, silver nitrate 74
g of an aqueous solution containing potassium bromide and potassium iodide at a molar ratio of 98/2, and [Ir (N
O) Cl ₅ ] salt was added in an amount of 1 × 10 ⁻⁶ mol per mol of silver, and the rhodium chloride salt was added in an amount of 1 × 10 ⁻⁴ mol per mol of silver.
While maintaining g7.7, it was added by a controlled double jet method. Thereafter, 4-hydroxy-6-methyl-1,
Add 3,3a, 7-tetrazaindene (TAI) and add N
Adjust the pH to 5.0 with aOH and adjust the average particle size to 0.0
Cubic silver iodobromide grains having a particle size of 6 μm and a monodispersity of 8% (100) face ratio of 87% were obtained.

This emulsion was subjected to coagulation sedimentation using a gelatin coagulant, and after desalting, 0.1 g of phenoxyethanol was added to adjust the pH to 5.9 and the pAg to 7.5 to obtain a silver halide emulsion. Further, chemical sensitization was performed with chloroauric acid and inorganic sulfur to obtain a silver halide emulsion A.

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

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

After the addition was completed, the mixture was further stirred for 30 minutes, and the water-soluble salts were removed by ultrafiltration. The obtained silver behenate was needle-shaped particles having an average particle size of 0.8 μm and a monodispersity of 8%.

(Preparation of Photosensitive Emulsion B) To this silver behenate dispersion, 0.01 mol of the silver halide emulsion A was added.
100 g of an n-butyl acetate solution of polyvinyl acetate (1.2 wt%) was gradually added with stirring to form a floc of the dispersion, and then water was removed, followed by two additional water washes and water removal. . Next, 2.5 wt% (1: 2 mixed solution of butyl acetate and isopropyl alcohol) of polyvinyl butyral (average molecular weight 3000) as a binder 60
g was added with stirring, and then polyvinyl butyral (average molecular weight: 4000) and isopropyl alcohol were added as a binder to the obtained gel-like mixture of behenic acid and silver halide to obtain a light-sensitive emulsion B. .

(Preparation of Coating Solution for Photosensitive Layer) The above-mentioned photosensitive emulsion B5
21 ° C. while stirring 00 g and 2-butanone 100 g.
Was kept warm. Pyridinium hydrobromide perbromide (PHP) (0.45 g) was added and stirred for 1 hour. Further, 3.25 ml of potassium bromide (10% methanol solution) was added, and the mixture was stirred for 30 minutes. Next, a mixed solution of 1,4-chloro-2-benzoylbenzoic acid and a supersensitizer (5-methyl-2-mercaptobenzimidazole) (mixing ratio 1: 250: 20, 0.1 % Methanol solution (7 ml) and stirred for 1 hour.
C. and stir for an additional 30 minutes. While keeping the temperature at 13 ° C., 480 g of polyvinyl butyral is added and sufficiently dissolved, and then the following additives are added at intervals of 15 minutes. The mixture was further stirred for 30 minutes and sufficiently dissolved to prepare a photosensitive layer coating solution.

Developer-1 (0.0484 mol) 15 g Desmodur N3300 (Mobay Inc., aliphatic isocyanate) 1.10 g Phthalazine 1.5 g Tetrachlorophthalic acid 0.5 g 4-Methylphthalic acid 0.5 g Squaric acid complex dye 8 mg

[0101]

Embedded image

<Protective Layer> (Preparation of Protective Layer Coating Solution) A protective layer coating solution having the following composition was prepared.

(1) Preparation of Cellulose Acetate Butyrate Premix Solution A 2500 g batch of the coating solution material was prepared as follows.
76.05% by weight of 2-butanone and 8.95% by weight of methanol were placed in a 1 gallon jar. The jar is G. K.
The system was equipped with a Heller 12P-3223 type mixer and a controller, and was stirred at 2000 rpm. Further, cellulose acetate butyrate (CAB171-15S)
15.00% by weight (manufactured by Eastman Kodak Co., Ltd.) was added, and the solution was stirred for 2 hours.

(2) Preparation of calcium carbonate premix A 300 g batch of the premix was prepared as follows.
90.32% by weight of the cellulose acetate butyrate premix solution obtained above was loaded onto a Werian Laboratory Blender equipped with a 32 oz. Stainless steel Variak variable power supply with lid (Welliang Products Division, Dynamics Corporation. Of America). The variac was set at 30 and stirring was started. 9.68% by weight of Pizzer Superflex SF200CaCO ₃ was added, the variac was set to 40 and the mixture was dispersed for 45 minutes.

(3) Preparation of protective layer coating solution A 600 g batch of the protective layer coating solution was prepared as follows.
90.32% by weight of the cellulose acetate butyrate premix solution obtained above, 48.05% by weight of calcium carbonate premix, 43.02% by weight of 2-butanone
And 5.16% by weight of methanol in a 32 ounce jar. The jar is G. K. Haller 12P-3
Equipped with 223 type mixer and controller, 1500
Stirred at rpm. Further, 0.30% by weight of acryloid A-21 (manufactured by Rohm and Haas), 0.27% by weight of 4-methylphthalic acid, 0.1 of tetrachlorophthalic anhydride
4% by weight, unevenness inhibitor (KH40: nonionic type)
(Perfluoroalkyl ethylene oxide adduct, manufactured by Asahi Glass Co., Ltd.)
Stirred for minutes.

<Backcoat Layer> (Preparation of Backcoat Layer Coating Solution) A backcoat layer coating solution having the following composition was prepared.

(1) Preparation of Cellulose Acetate Butyrate Premix Solution A 2500 g batch of the coating solution material was prepared as follows.
87.28% by weight of 2-butanone was placed in a 1 gallon jar. The jar is G. K. Haller 12P-32
Equipped with 23 type mixer and controller, 2000r
Stirred at pm. Further, 12.55% by weight of cellulose acetate butyrate (CAB 381-20, manufactured by Eastman Kodak Co., Ltd.) and 0.17% by weight of Vittel manufactured by Goodyear were added, and the solution was stirred for 2 hours.

(2) Preparation of Syloid X6000 Premix A 2500 g batch of the premix was prepared as follows. 99.62% by weight of 2-butanone and 0.38% by weight of silica (Syloid 74-X6000 WR Grace) were put into a 1-gallon jar to form a slurry. The slurry was homogenized with a single pass at 4000 psi in a homogenizer.

(3) Preparation of coating solution for back coat layer Square acid complex dye (antihalation dye) 0.09
Jars of 4% by weight and 7.87% by weight of 2-butanone were sonicated until dissolved. Further, the above cellulose acetate butyrate premix solution 78.
67% by weight was added and the solution was stirred well. Subsequently, the above Syloid X6000 / butanone premix 7.8 was used.
The solution was stirred well with 7% by weight in a jar. Finally, an antistatic agent (S-381: a non-ionic type, a perfluoroalkyl-containing oligomer manufactured by Asahi Glass Co., Ltd.)
57% by weight and 3.93% by weight of 2-butanone were added and the solution was stirred well.

<Coating step and preparation of heat-developable photographic light-sensitive material> The coating was carried out using the extrusion coater shown in FIG. Simultaneous multilayer coating of the layer coating solution was performed. The photosensitive layer coating solution was uniformly coated so that the coated silver amount was 2.0 g / m ² and the polyvinyl butyral as a binder was 3.5 g / m ² . The protective layer was applied to a dry film thickness of 2.0 μm.

The amount of solvent remaining in the photosensitive layer when the simultaneous multi-layer coating was performed was measured under the following conditions. That is, the amount of residual solvent in the photosensitive layer was determined by measuring immediately after coating. Gas chromatography was used to measure the amount of solvent. As a result, the remaining amount of the solvent in the photosensitive layer was 95% by weight of the total amount of the solvent used in the photosensitive layer. Thereafter, the coated sample was heated and dried at 90 ° C. for 2 minutes, and then subjected to a heat treatment at 55 ° C. for 4 minutes, and gradually allowed to cool to room temperature.

Next, the coating solution for the back coat layer was placed on the extrusion coater shown in FIG. 1 and applied to the surface of the support opposite to the side having the photosensitive layer. The application conditions were the same as above, using an extrusion coater, and under infrared safe light conditions. The coating knife was set at a position 76.2 mm from the surface of the support. Then, 12
Heat drying was performed at 0 ° C. for 2 minutes, and heat treatment was performed at 55 ° C. for 3 minutes, and then gradually cooled to room temperature. Thus, a photothermographic material was prepared. This is designated as Sample 1.

Samples 2 to 7 were prepared by changing the presence / absence of polyester, the heat treatment and the conditions of the multilayer coating method for the protective layer and the photosensitive layer as shown in Table 1, and the following evaluations were made.

The polyester was added to each of the layers at the same time as the photosensitive emulsion and MEK for the photosensitive layer. With respect to the protective layer and the back coat layer, the polyester is added after the respective coating solutions are prepared,
The mixture was further stirred for 1 hour to be sufficiently dissolved.

<Evaluation> (Adhesion) Samples 1 to 7 obtained in this manner were subjected to 25 ° C.
-Humidity was adjusted in an atmosphere of 55% RH, and the following adhesion evaluation was performed.

The photosensitive layer surface and the back coat layer surface of the sample cut to 3 cm in length and 12 cm in width were cut with a razor into the photosensitive layer surface and the surface of the back coat layer so as not to reach the support of 6 pieces each in the vertical and horizontal directions, and 25 squares were formed. After a cellophane tape (manufactured by Nichiban Cellotape Co., Ltd.) having a width of 25 mm was adhered on this and strongly pressed, 9
Peel quickly at a peel angle of 0 °. This evaluation is based on raw samples,
And a sample developed with a heat roller type developing machine at 120 ° C. for 15 seconds. It was classified into ranks A to D according to the number of peeled cells. Among the following ranks, A and B ranks are practically acceptable.

A rank: number of peeled cells 0 sphere B rank: number of peeled cells 1 to 3 C rank: number of peeled cells 4 to 10 D rank: number of peeled cells 11 to 25

(Photo Performance) A sample was 3.5 cm × 15 cm.
After exposing with a laser sensitometer equipped with an 810 nm diode, processing (developing) at 120 ° C. for 15 seconds,
The obtained image was evaluated using a densitometer. The measurement results were evaluated based on Dmin (fog) and sensitivity (reciprocal of the ratio of the exposure amount giving a density higher than Dmin by 1.0).

Table 1 shows the obtained results.

[0120]

[Table 1]

As is clear from Table 1, the heat-developable photographic light-sensitive material of the present invention has good adhesion between the support and the photosensitive layer, the support and the back coat layer, or between the layers after raw storage or heat treatment. Further, it can be seen that the film has low fog density and good photographic performance without a decrease in sensitivity. Also, it can be seen that the comparative example in which the amount of the residual solvent in the photosensitive layer exceeds 500 mg / m ² has a high fog density, while the amount of the residual solvent below 30 mg / m ² causes a decrease in sensitivity.

Example 2 Samples 2-1 to 2-7 were obtained by using the sample 3 obtained in the example 1 and changing the conditions of the addition of polyester to the back coat layer and the heat treatment after coating as shown in Table 2. It was fabricated and evaluated for (adhesion) in Example 1. Table 2 shows the obtained results.

[0123]

[Table 2]

As is evident from Table 2, the backcoat layer containing the polyester and formed in the order of coating and heat treatment has good adhesion between the support and the backcoat layer. .

[0125]

According to the present invention, the adhesiveness between the support and the constituent layers (photosensitive layer, back coat layer, etc.) and between the constituent layers (photosensitive layer, protective layer) of the photothermographic material is improved. It has a remarkably excellent effect that it can be performed. Also, it has a remarkably excellent effect of reducing fog density and having excellent photographic performance without a decrease in sensitivity.

[Brief description of the drawings]

FIG. 1 is a schematic view of an extrusion coating device.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Extrusion coater 2 Manifold part 3 Slot part 4 Support body 5 Vacuum part 6 Suction port 7 Coating liquid 8 Coating liquid

Claims (6)

[Claims] 1. A support comprising: a) a photosensitive layer containing organic silver, silver halide and a reducing agent on a support; and b) a layer provided on a side farther than the photosensitive layer with respect to the support, c) In a photothermographic material having at least one layer provided on the side opposite to the side having the photosensitive layer with a support interposed therebetween, each layer contains polyester, and at least one side is coated and heat-treated. A heat-developable photographic material characterized by being formed in the following order: 2. The photothermographic material according to claim 1, wherein the layer b) is provided on the photosensitive layer before the residual amount of the solvent in the photosensitive layer becomes 70% by weight or less. 3. The total amount of the solvent in all layers of the photothermographic material after the heat treatment is from 30 to 500 per m ^{2 of the} photographic material.
3. The photothermographic material according to claim 1, wherein the amount is mg. 4. A support comprising: a) a photosensitive layer containing organic silver, silver halide and a reducing agent on a support; and b) a layer provided on a side farther than the photosensitive layer with respect to the support, c). In producing a photothermographic material having at least one layer provided on the side opposite to the side having the photosensitive layer with the support interposed therebetween, and each of the layers contains polyester, at least one side structure A method for producing a photothermographic material, wherein the layer is formed by heat treatment after coating. 5. A photothermographic photograph according to claim 4, further comprising a step of providing the layer (b) on the photosensitive layer before the residual amount of the solvent in the photosensitive layer becomes 70% by weight or less. Manufacturing method of photosensitive material. 6. An image forming method, wherein the photothermographic material according to claim 1 is exposed and then developed by a heat treatment at 80 to 200 ° C.