JP2002049116A - Heat developable photosensitive material - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a heat developable photosensitive material excellent in photographic performance and image preservability and having no harmful effect on working environment. SOLUTION: In the heat developable photosensitive material with constitutional layers comprising at least one image forming layer containing at least one photosensitive silver halide, a non-photosensitive organic silver salt, a reducing agent for silver ions and a binder and at least one non-photosensitive layer on at least one face of the base, the total water content of the constitutional layers on the base at 25 deg.C and 60% relative humidity is 0.1-1.5% and the total solvent content is 0.001-50 ppm.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a photothermographic material excellent in photographic performance and image storability and particularly suitable for medical diagnostic use.

[0002]

2. Description of the Related Art In recent years, in the field of medical diagnostic films and photoengraving films, it has been strongly desired to reduce the amount of processing waste liquid from the viewpoint of environmental protection and space saving.
Therefore, a laser imagesetter or laser
There is a need for technical development of photothermographic materials for medical diagnostics and photoengraving that can be efficiently exposed by an imager and can form a clear black image with high resolution and sharpness. I have. According to such a photothermographic material, it is possible to supply a customer with a simpler and more environmentally friendly photothermographic processing system that does not require solution-based processing chemicals.

[0003] In the field of general image forming materials, there is a similar demand, but in particular, medical diagnostic images are required to be finely described, so that high quality images having excellent sharpness and granularity are required, and diagnostic images are required. There is a feature that a cool black image is preferred from the viewpoint of ease of operation. At present, various hard copy systems using pigments and dyes, such as ink jet printers and electrophotographs, are distributed as general image forming systems, but there is no satisfactory system for outputting medical images.

A thermal image forming system using an organic silver salt is disclosed in, for example, US Pat. No. 3,152,904,
No. 3,457,075, and D.C. Klosterboer, "Thermally Processed Silver Systems" (Imaging Processes and Materials, Neblette 8
Edition, J. Sturge, V.S. Wall Worth (Wa
lworth), A. Editing Shepp, Chapter 9, Chapter 2
79, 1989).

A photothermographic material generally comprises a reducible silver salt (for example, an organic silver salt), a catalytically active amount of a photocatalyst (for example, silver halide), a reducing agent, and if necessary, a color tone controlling silver tone. It has an image forming layer (photosensitive layer) dispersed in a binder matrix. The photothermographic material is stable at room temperature, but when heated to a high temperature (for example, 80 ° C. or higher) after image exposure, a redox reaction between a reducible silver salt (functioning as an oxidizing agent) and a reducing agent. As a result, a black silver image is formed. This oxidation-reduction reaction is promoted by the catalytic action of the latent image of silver halide formed by exposure. The silver formed by the reaction of the reducible silver salt in the exposed areas turns black and forms an image because it contrasts with the unexposed areas.

However, in these photothermographic materials, there is no fixing step after the heat development, so that there is a problem that the density of the undeveloped portion increases and the image is deteriorated. In addition, it was necessary to deal with a decrease in sensitivity.

[0007]

SUMMARY OF THE INVENTION In view of the above problems of the prior art, an object of the present invention is to provide a photothermographic material having excellent photographic performance and image storability. In particular, it is an object of the present invention to provide a photothermographic material which does not adversely affect the working environment.

[0008]

In order to solve the above-mentioned problems, the present invention has been intensively studied. By controlling the water content ratio within a certain range,
The present inventors have found that a photothermographic material excellent in photographic performance and image storability can be produced, and have reached the present invention. That is, the present invention provides at least one surface of at least one surface of a support.
Having at least one image-forming layer containing at least one photosensitive silver halide, a non-photosensitive organic silver salt, a reducing agent for silver ions and a binder, and at least one non-photosensitive layer In the photothermographic material, the water content of the entire constituent layer on the support is 0.1 to 1.5% at 25 ° C. and a relative humidity of 60%, and the content of the solvent is 0.001.
To 50 ppm. The ratio (a / b) of the water content (a) of the non-photosensitive layer to the water content (b) of the image forming layer is preferably 0.06 to 6. Further, the present invention provides at least one photosensitive silver halide on at least one surface of a support.
In the photothermographic material having at least one image forming layer containing a non-photosensitive organic silver salt, a reducing agent for silver ions and a binder, and at least one non-photosensitive layer, The ratio (a / b) of the water content (a) of the photosensitive layer to the water content (b) of the image forming layer is 0.06 to
6 and a solvent content of 0.001 to 50 ppm. In this specification, “to” means a range including the numerical values described before and after it as a minimum value and a maximum value, respectively.

[0009]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The photothermographic material of the present invention will be described below in detail. The photothermographic material of the present invention comprises at least one photosensitive silver halide, a non-photosensitive organic silver salt, a reducing agent for silver ions, and a binder containing at least one photosensitive silver halide on at least one surface of a support.
It has an image forming layer and at least one non-photosensitive layer. Such a constituent layer composed of the image forming layer and the non-photosensitive layer may be formed on only one side of the support, or may be formed on both sides. The feature of the present invention is that in such a photothermographic material, the following conditions (1) and (2) are satisfied, or
The point is that the conditions of (2) and (3) are satisfied. Preferred are photothermographic materials satisfying all the conditions (1), (2) and (3). (1) The water content of the entire constituent layer is 25 ° C. and the relative humidity is 60
% To be 0.1 to 1.5%. (2) The content of the solvent is 0.001 to 50 ppm. (3) Water content of the non-photosensitive layer constituting the constituent layer (a)
And the ratio (a / b) of the water content (b) of the image forming layer to 0.
06 to 6.

The moisture content of the entire constituent layer defined by the above condition (1) is calculated by the following method. That is,
The photothermographic material is conditioned at 25 ° C. and a relative humidity of 60% for 24 hours, and after measuring the sample mass a1, the water content b1 is measured by the Karl Fischer method. Thereafter, a sample is prepared by removing the constituent layer on the support with warm water and an organic solvent, and after measuring the sample mass a2, the water content b2 is measured by the Karl Fischer method. Based on these measurement results, the moisture content of the constituent layers can be calculated by the following equation. (B1-b2) / (a1-a2) The above condition (1) specifies that the water content of the entire constituent layer calculated by such a method is 0.1 to 1.5%. . When the constituent layer composed of the image forming layer and the non-photosensitive layer satisfying the conditions of the present invention is formed on both sides of the support, the water content of the constituent layer on at least one side is 0.1.
The water content of the constituent layers on both sides is preferably 0.1 to 1.5%. The water content at 25 ° C. and a relative humidity of 60% is preferably from 0.2 to 1.3.
%, More preferably 0.3 to 1.1%, even more preferably 0.4 to 1.0%. There is no particular limitation on the method of adjusting the water content of the entire constituent layer so as to satisfy the condition (1). For example, it can be controlled by adjusting the amounts of the hydrophilic compound and the hydrophilic binder contained in each layer.

The content of the solvent contained in the condition (2) is calculated by the following method. That is, the mass of the sample is measured immediately after the photothermographic material is removed from the package, and the material is immersed in a sufficient amount of hexafluoroisopropyl alcohol for 24 hours. Hexafluoroisopropyl alcohol after immersion for 24 hours is analyzed by gas chromatography to determine the total amount d of the organic solvent eluted from the sample. Based on these measurement results, the content of the solvent can be calculated by the following equation. (D / c) × 10 ⁶ [unit ppm] The condition (2) specifies that the content of the solvent calculated by such a method is 0.001 to 50 ppm. The content of the solvent is 0.001 to 30 pp
m, more preferably 0.001 to 20 ppm, and particularly preferably 0.001 to 10 ppm. There is no particular limitation on the method for adjusting the amount of the contained solvent so as to satisfy the condition (2). For example, it can be controlled by adjusting the amount of the organic solvent contained in the coating solution used to form the constituent layer, or by adjusting the temperature and humidity during coating and drying.

The organic solvent used in the photothermographic material of the present invention includes a new edition solvent pocket book (Ohm, 1
994), but organic solvents that can be used in the present invention are not limited thereto. The organic solvent used in the photothermographic material of the present invention preferably has a boiling point of 40 to 180 ° C. Specifically, hexane, cyclohexane,
Toluene, methanol, ethanol, isopropanol, acetone, methyl ethyl ketone, ethyl acetate, 1,
1,1-trichloroethane, tetrahydrofuran, triethylamine, thiophene, trifluoroethanol,
Perfluoropentane, xylene, n-butanol, phenol, methyl isobutyl ketone, cyclohexanone, butyl acetate, diethyl carbonate, chlorobenzene, dibutyl ether, anisole, ethylene glycol diethyl ether, N, N-dimethylformamide, morpholine, propane sultone, perfluoro Tributylamine and the like. The amount of the organic solvent in the present invention is suitably determined based on, for example, the total amount of methyl ethyl ketone, toluene, acetone, methanol, and n-butanol, and is particularly preferably determined based on the total amount of methyl ethyl ketone.

The ratio defined by the above condition (3) can be calculated by determining the water content of the non-photosensitive layer and the image forming layer by the Karl Fischer method. The water content ratio of the non-photosensitive layer to the image forming layer is 0.06 to 6, preferably 0.08 to 5, more preferably 0.1 to 6.
4, and more preferably 0.12 to 3.

Next, the materials used for the photothermographic material of the present invention will be described. The organic silver salt that can be used in the present invention is relatively stable to light, but at 80 ° C. or less in the presence of an exposed photocatalyst (such as a latent image of a photosensitive silver halide) and a reducing agent. It is a silver salt that forms a silver image when heated as described above. The organic silver salt can be any organic substance including a source capable of reducing silver ions. Such a non-photosensitive organic silver salt is disclosed in JP-A-10-6289.
No. 9, paragraphs 0048 to 0049, European Patent Publication No. 0803764A1, page 18, line 24 to
Page 19, line 37, EP-A-0 962 812
No. A1. Silver salts of organic acids, especially silver salts of long-chain aliphatic carboxylic acids (with 10 to 30 carbon atoms, preferably 15 to 28 carbon atoms) are preferred. Preferred examples of the organic silver salt include silver behenate, silver arachidate, silver stearate, silver oleate, silver laurate, silver caproate, silver myristate, silver palmitate, and mixtures thereof. In the present invention, among these organic silver salts, it is preferable to use an organic acid silver salt having a silver behenate content of 75 mol% or more.

The shape of the organic silver salt that can be used in the present invention is not particularly limited, and may be needle-like, rod-like, plate-like, or scaly. In the present invention, scaly organic silver salts are preferred. In the present specification, the scaly organic silver salt is defined as follows. The silver salt of the organic acid was observed with an electron microscope, and the shape of the silver salt of the organic acid was approximated to a rectangular parallelepiped.
May be the same as b. ) When the shorter numerical value a,
Calculate with b and obtain x as follows. x = b / a x is obtained for about 200 particles in this manner,
Assuming that the average value x (average), x (average) ≧ 1.5
The one satisfying the above relationship is scaly. Preferably 30
≧ x (average) ≧ 1.5, more preferably 20 ≧ x (average) ≧ 2.0. By the way, needle shape is 1 ≦ x (average) <
1.5.

In the scaly particles, a can be regarded as the thickness of a tabular particle having a main plane with b and c as sides. The average of a is preferably 0.01 to 0.23 μm, more preferably 0.1 to 0.20 μm. The average of c / b is preferably 1 to 6, more preferably 1.05 to 4, still more preferably 1.1 to 3, and particularly preferably 1.1 to 2.

The particle size distribution of the organic silver salt is preferably monodispersed. The monodispersion is preferably 100% or less, more preferably 80% or less, and still more preferably 50% of the value obtained by dividing the standard deviation of the length of each of the minor axis and major axis by the minor axis and major axis, respectively. It is as follows. The shape of the organic silver salt can be measured from a transmission electron microscope image of the organic silver salt dispersion. Another method for measuring monodispersity is to determine the standard deviation of the volume-weighted average diameter of the organic silver salt, and the percentage (coefficient of variation) divided by the volume-weighted average diameter is preferably 100% or less. It is preferably at most 80%, more preferably at most 50%. As a measuring method, for example, the organic silver salt dispersed in a liquid is irradiated with laser light, and the particle size (volume weighted average diameter) obtained by obtaining an autocorrelation function with respect to a time change of the fluctuation of the scattered light is obtained. Can be.

Known methods can be applied to the production of the organic acid silver used in the present invention and its dispersion method. For example, the above-mentioned JP-A-10-62899, European Patent Publication No. 0803763A1, and European Patent Publication 962812A1
Reference can be made.

When a photosensitive silver salt is present in the dispersion of the organic silver salt, fog increases and the sensitivity is remarkably reduced. Therefore, it is more preferable that the photosensitive silver salt is not substantially contained at the time of dispersion. According to the present invention, the amount of the photosensitive silver salt in the aqueous dispersion to be dispersed is 0.1 mol% or less based on 1 mol of the organic acid silver salt in the liquid, and the photosensitive silver salt is positively added. Not something.

In the present invention, it is possible to produce a photothermographic material by mixing an aqueous dispersion of an organic silver salt and an aqueous dispersion of a photosensitive silver salt. The ratio of the photosensitive silver salt to the organic silver salt is preferably in the range of 1 to 30 mol%, more preferably 3 to 20 mol%, and particularly preferably 5 to 15 mol%. Mixing two or more aqueous dispersions of organic silver salts with two or more aqueous dispersions of photosensitive silver salts during mixing is a method preferably used for controlling photographic characteristics.

In the present invention, the organic silver salt can be used in a desired amount.
However, the amount of silver is 0.1 to 5 g / m ^TwoIs preferred, and
Preferably 1 to 3 g / m^TwoIt is.

The photothermographic material of the present invention preferably contains a reducing agent for an organic silver salt. The reducing agent for the organic silver salt may be any substance (preferably an organic substance) that reduces silver ions to metallic silver. Such a reducing agent is
Paragraph Nos. 0043-0 of JP-A-11-65021
045 and European Patent Publication No. 0803764A1, page 7, line 34 to page 18, line 12. In the present invention, the reducing agent is preferably a bisphenol reducing agent, and more preferably a compound represented by the following general formula (I).

[0023]

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[In the general formula (I), R ¹¹ and R
^{11 ′} each independently represents an alkyl group. R ¹² and R
^{12 ′} each independently represents a hydrogen atom or a group that can be substituted on a benzene ring. X ¹¹ and X ^{11 ′} each independently represent a hydrogen atom or a group that can be substituted on a benzene ring. R ¹¹ and X ^11, R ^{11 'and} X ^11', R ¹² and X ^11, and R ^{12 'and} X ^11'
May combine with each other to form a ring. L represents a —S— group or a —CHR ¹³ — group, and R ¹³ represents a hydrogen atom or an alkyl group. ]

The reducing agent represented by formula (I) will be described in detail. In the general formula (I), R ¹¹ and R
^{11 ′} each independently represents an alkyl group. In particular,
It is a substituted or unsubstituted, linear, branched or cyclic alkyl group, preferably an alkyl group having 1 to 20 carbon atoms. The substituent of the alkyl group is not particularly limited, but is preferably an aryl group, a hydroxy group, an alkoxy group, an aryloxy group, an alkylthio group, an arylthio group, an acylamino group, a sulfonamide group, a sulfonyl group, a phosphoryl group, Examples include an acyl group, a carbamoyl group, an ester group, and a halogen atom.

R ¹¹ and R ^{11 ′} are more preferably a secondary or tertiary alkyl group having 3 to 15 carbon atoms, specifically, isopropyl, isobutyl, tert-butyl, and tert-amyl groups. Tert-octyl group, cyclohexyl group, cyclopentyl group, 1-methylcyclohexyl group, 1-methylcyclopropyl group and the like.
More preferred are tertiary alkyl groups having 4 to 12 carbon atoms, and among them, tert-butyl, tert-amyl and 1-methylcyclohexyl are particularly preferred, and tert-butyl is most preferred.

R ¹² and R ^{12 ′} each independently represent a hydrogen atom or a group that can be substituted on a benzene ring. X ¹¹ and X ^{11 ′} each independently represent a hydrogen atom or a group that can be substituted on a benzene ring. The group that can be substituted on the benzene ring preferably includes an alkyl group, an aryl group, a halogen atom, an alkoxy group, an acylamino group, and the like.

R ¹² and R ^{12 ′} are preferably those having 1 carbon atom
To 20 alkyl groups, specifically, methyl, ethyl, propyl, butyl, isopropyl, ter
Examples include a t-butyl group, a tert-amyl group, a cyclohexyl group, a 1-methylcyclohexyl group, a benzyl group, a methoxymethyl group, and a methoxyethyl group. More preferred are a methyl group, an ethyl group, a propyl group, an isopropyl group and a tert-butyl group. X ¹¹ and X
^{11 ′} is preferably a hydrogen atom, a halogen atom or an alkyl group, particularly preferably a hydrogen atom. R ¹¹ and X ^11, R ^{11 'and} X ^11', R ¹² and X ^11, and R ^{12 'and} X ^11'
May combine with each other to form a ring. This ring is preferably a 5- to 7-membered ring, more preferably a saturated 6-membered ring.

L represents a —S— group or a —CHR ¹³ — group, and R ¹³ represents a hydrogen atom or an alkyl group. R ¹³ is
Specifically, it is a substituted or unsubstituted linear, branched or cyclic alkyl group, preferably an alkyl group having 1 to 20 carbon atoms. Specific examples of the unsubstituted alkyl group represented by R ¹³ include a methyl group, an ethyl group, a propyl group,
Examples thereof include a butyl group, a heptyl group, an undecyl group, an isopropyl group, a 1-ethylpentyl group, and a 2,4,4-trimethylpentyl group. Substituent of the substituted alkyl groups represented by R ¹³ are the same as the substituents for the alkyl group represented by R ¹¹ and R ^{11 '.}

L is preferably a --CHR ¹³ -group. R
¹³ is preferably a hydrogen atom or an alkyl group having 1 to 15 carbon atoms, and the alkyl group is preferably a primary or secondary alkyl group having 1 to 8 carbon atoms, more preferably a methyl group, Ethyl group, n-propyl group, isopropyl group or 2,4,4-trimethylpentyl group, more preferably methyl group, ethyl group, n-propyl group or isopropyl group, particularly preferably,
It is a methyl group, an ethyl group or an n-propyl group.

When R ¹³ is a hydrogen atom, R ¹² and R
^{12 ′} is preferably an alkyl group having 2 or more carbon atoms,
It is more preferably an alkyl group having 2 to 5 carbon atoms, further preferably an ethyl group or a propyl group, and most preferably an ethyl group. When R ¹³ is an alkyl group, R ¹² and R ^{12 ′} are preferably an alkyl group, particularly preferably a methyl group.

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

[0033]

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[0034]

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[0035]

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[0036]

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[0037]

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In the present invention, the amount of the reducing agent added is 0.01
To 5.0 g / m ² , preferably 0.1 to 3.0 g / m ² .
The content is more preferably 0 g / m ² , preferably 5 to 50% by mole, and more preferably 10 to 40% by mole based on 1 mole of silver on the surface having the image forming layer. The reducing agent is preferably contained in the image forming layer.

The reducing agent may be contained in the coating solution by any method such as a solution form, an emulsified dispersion form, and a solid fine particle dispersion form, and may be contained in the photothermographic material. Well-known emulsification dispersion methods include oils such as dibutyl phthalate, tricresyl phosphate, glyceryl triacetate or diethyl phthalate, and dissolution using an auxiliary solvent such as ethyl acetate or cyclohexanone, and mechanically dispersing the emulsified dispersion. There is a method of manufacturing.

As a method for dispersing solid fine particles, a powder of a reducing agent is dispersed in a suitable solvent such as water by a ball mill, a colloid mill, a vibrating ball mill, a sand mill, a jet mill, a roller mill, or ultrasonic waves to obtain a solid dispersion. Is produced. In this case, a protective colloid (for example, polyvinyl alcohol) and a surfactant (for example, an anionic surfactant such as sodium triisopropylnaphthalenesulfonate (a mixture of three isopropyl groups having different substitution positions)) may be used. Good. The aqueous dispersion can contain a preservative (eg, benzoisothiazolinone sodium salt).

In the photothermographic material of the present invention, a phenol derivative represented by the formula (A) described in Japanese Patent Application No. 11-73951 is preferably used as a development accelerator.

When the reducing agent in the present invention has an aromatic hydroxyl group (-OH), particularly in the case of the above-mentioned bisphenols, the non-reducing agent has a group capable of forming a hydrogen bond with these groups. It is preferable to use a compound having an acidic property. Examples of the group that forms a hydrogen bond with a hydroxyl group or an amino group include a phosphoryl group, a sulfoxide group, a sulfonyl group, a carbonyl group, an amide group, an ester group, an urethane group, a ureido group, a tertiary amino group, and a nitrogen-containing aromatic group. No. Among them, preferred are a phosphoryl group, a sulfoxide group and an amide group (provided that they have no> NH group,
> NR (R is a substituent other than H). ), Urethane group (provided that it does not have a> NH group,
> NR (R is a substituent other than H). ), Ureido group (provided that it has no> NH group,
> NR (R is a substituent other than H). ). In the present invention, a particularly preferred compound having a hydrogen bonding property is a compound represented by the following general formula (II).

[0043]

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[In the general formula (II), R ²¹ , R ²² and R ²³ each independently represent an alkyl group, an aryl group, an alkoxy group, an aryloxy group, an amino group or a heterocyclic group. It may be substituted or may have a substituent, and any two of R ²¹ , R ²² and R ²³ may be bonded to each other to form a ring. ]

In the present invention, a compound represented by the above general formula (II) is preferably used as the hydrogen bonding compound. In the general formula (II), R ²¹ , R ²² and R ²³ each independently represent an alkyl group, an aryl group, an alkoxy group, an aryloxy group, an amino group or a heterocyclic group, and these groups are unsubstituted. May also have a substituent, and any two of R ²¹ , R ²² and R ²³ may form a ring. When R ²¹ , R ²² and R ²³ have a substituent, examples of the substituent include a halogen atom, an alkyl group,
Aryl group, alkoxy group, amino group, acyl group, acylamino group, alkylthio group, arylthio group, sulfonamide group, acyloxy group, oxycarbonyl group, carbamoyl group, sulfamoyl group, sulfonyl group, phosphoryl group and the like, preferably An alkyl group or an aryl group, and specific examples include a methyl group, an ethyl group, an isopropyl group, a tert-butyl group, and a tert-
Octyl group, phenyl group, 4-alkoxyphenyl group,
4-acyloxyphenyl group and the like.

Specific examples of the groups represented by R ²¹ , R ²² and R ²³ include a methyl group, an ethyl group, a butyl group, an octyl group, a dodecyl group, an isopropyl group, a tert-butyl group, a tert-amyl group, a substituted or unsubstituted alkyl group such as a tert-octyl group, a cyclohexyl group, a 1-methylcyclohexyl group, a benzyl group, a phenethyl group, a 2-phenoxypropyl group; a phenyl group, a cresyl group,
Substituted or unsubstituted aryl groups such as xylyl group, naphthyl group, 4-tert-butylphenyl group, 4-tert-octylphenyl group, 4-anisidyl group, 3,5-dichlorophenyl group; methoxy group, ethoxy group, butoxy group An octyloxy group, a 2-ethylhexyloxy group,
Substituted or unsubstituted alkoxyl groups such as 3,5,5-trimethylhexyloxy group, dodecyloxy group, cyclohexyloxy group, 4-methylcyclohexyloxy group and benzyloxy group; phenoxy group, cresyloxy group, isopropylphenoxy group, 4- a substituted or unsubstituted aryloxy group such as a tert-butylphenoxy group, a naphthoxy group, a biphenyloxy group; an amino group, a dimethylamino group, a diethylamino group, a dibutylamino group,
Dioctylamino group, N-methyl-N-hexylamino group, dicyclohexylamino group, diphenylamino group,
Substituted or unsubstituted amino groups such as N-methyl-N-phenylamino group; 2-pyridyl group, 4-pyridyl group, 2-
Furanyl group, 4-piperidinyl group, 8-quinolyl group, 5
-A heterocyclic group such as a quinolyl group.

R ²¹ , R ²² and R ²³ are preferably an alkyl group, an aryl group, an alkoxy group or an aryloxy group. From the viewpoint of the effects of the present invention, one or more of R ²¹ , R ²² and R ²³ are preferably an alkyl group or an aryl group, and more preferably two or more are an alkyl group or an aryl group. Further, it is preferable that R ²¹ , R ²² and R ²³ be the same group in that they can be obtained at low cost.

Specific examples of the compound represented by formula (II) are shown below, but the compounds which can be used in the present invention are not limited to these.

[0049]

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[0050]

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[0051]

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[0052]

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The compound of the general formula (II) can be contained in a coating solution in the form of a solution, an emulsified dispersion or a solid-dispersed fine particle dispersion as in the case of the reducing agent, and used in a photothermographic material. The compound of the general formula (II) forms a hydrogen-bonding complex with a compound having a phenolic hydroxyl group and an amino group in a solution state, and depending on the combination of the reducing agent and the compound of the general formula (II), a complex may be formed. It can be isolated in crystalline form. It is particularly preferable to use the crystal powder isolated in this way as a solid dispersion fine particle dispersion in order to obtain stable performance. Further, a method in which the reducing agent and the compound of the formula (II) are mixed in a powder form and complexed at the time of dispersion with a sand grinder mill or the like using an appropriate dispersant can also be preferably used. The compound of the general formula (II) is preferably used in a range of 1 to 200 mol%, more preferably in a range of 10 to 150 mol%, and still more preferably in a range of 30 to 100 mol%, based on the reducing agent. It is.

The photosensitive silver halide used in the present invention is not particularly limited as a halogen composition, and silver chloride, silver chlorobromide, silver bromide, silver iodobromide, and silver iodochlorobromide can be used. . The distribution of the halogen composition in the grains may be uniform, the halogen composition may be changed stepwise, or may be changed continuously. Further, silver halide grains having a core / shell structure can be preferably used. The preferred structure is a two- to five-layer structure, and more preferably, a core / shell particle having a two- to four-layer structure can be used. A technique for localizing silver bromide on the surface of silver chloride or silver chlorobromide grains can also be preferably used.

Methods for forming photosensitive silver halide are well known in the art and are described, for example, in Research Disclosure No. 17029, June 1978, and US Pat. No. 3,700,458. Specifically, a photosensitive silver halide is prepared by adding a silver supply compound and a halogen supply compound to gelatin or another polymer solution,
Thereafter, a method of mixing with an organic silver salt is used. Further, paragraphs 0217 to 02 of JP-A-11-119374 are used.
24, and the methods described in Japanese Patent Application Nos. 11-98708 and 11-84182 are also preferable.

The grain size of the photosensitive silver halide is preferably small for the purpose of suppressing white turbidity after image formation, specifically, 0.20 μm or less, more preferably 0.01 to 0.15 μm, and furthermore, Preferably 0.02-
0.12 μm is preferred. The grain size as used herein means a diameter when converted into a circular image having the same area as the projected area of a silver halide grain (in the case of a tabular grain, the projected area of a main plane).

The shape of the silver halide grains is cubic,
Octahedral, tabular particles, spherical particles, rod-like particles, potato-like particles and the like can be mentioned. In the present invention, cubic particles are particularly preferable. Grains having rounded corners of silver halide grains can also be preferably used. The surface index (mirror index) of the outer surface of the photosensitive silver halide grains is not particularly limited. preferable. The ratio is preferably 50% or more, more preferably 65% or more, and still more preferably 80% or more. The ratio of the Miller index {100} plane is determined by T. Tani; J. Imaging Sci., 29, 165 (1985) utilizing the dependence of the adsorption of the sensitizing dye on the {111} plane and the {100} plane.
Year).

In the present invention, hexacyano metal complex is
Silver halide grains present on the outermost surface of the particles are preferred. Six
As the cyano metal complex, [Fe (CN)₆]^Four-, [F
e (CN)₆]^3-, [Ru (CN)₆]^Four-, [Os (C
N)₆]^Four-, [Co (CN)₆] ^3-, [Rh (CN)₆]
^3-, [Ir (CN)₆]^3-, [Cr (CN)₆]^3-, [R
e (CN)₆]^3-And the like. In the present invention
Hexacyano Fe complexes are preferred.

The hexacyano metal complex is present in the form of ions in an aqueous solution, so that the counter cation is not important. However, the hexacyano metal complex is easily miscible with water and is compatible with the precipitation operation of a silver halide emulsion. Use of alkali metal ions such as ions, rubidium ions, cesium ions, and lithium ions, ammonium ions, and alkylammonium ions (for example, tetramethylammonium ion, tetraethylammonium ion, tetrapropylammonium ion, and tetra (n-butyl) ammonium ion) Is preferred.

The hexacyano metal complex can be prepared by mixing a water-miscible organic solvent (eg, alcohols, ethers, glycols, ketones, esters, amides, etc.) or gelatin with water. And can be added as a mixture.

The addition amount of the hexacyano metal complex is preferably from 1 × 10 ⁻⁵ mol to 1 × 10 ⁻² mol, more preferably from 1 × 10 ⁻⁴ mol to 1 × 10 ⁻³ mol, per mol of silver. .

In order for the hexacyano metal complex to be present on the outermost surface of the silver halide grains, the addition of the hexacyano metal complex to the aqueous solution of silver nitrate used for grain formation is followed by sulfur sensitization, selenium sensitization and tellurium sensitization. Is added directly before the completion of the preparation step before the chemical sensitization step for performing noble metal sensitization such as chalcogen sensitization or gold sensitization, during the water washing step, during the dispersion step, or before the chemical sensitization step. In order to prevent the growth of silver halide fine particles, it is preferable to add the hexacyano metal complex immediately after the formation of the grains, and it is preferable to add the complex before the completion of the charging step.

Incidentally, the addition of the hexacyano metal complex may be started after 96% by mass of the total amount of silver nitrate added for grain formation, or started after 98% by mass is added. More preferably, it is particularly preferable after adding 99% by mass.

When these hexacyano metal complexes are added after the addition of an aqueous silver nitrate solution immediately before the completion of grain formation, they can be adsorbed on the outermost surface of silver halide grains, and most of them are hardly soluble in silver ions on the grain surface. Forms salt. Since the silver salt of hexacyanoiron (II) is a salt that is less soluble than AgI, it can be prevented from being redissolved by fine particles,
It has become possible to produce silver halide fine grains having a small grain size.

The photosensitive silver halide grains can contain a metal or a metal complex of Group 8 to Group 10 of the periodic table (showing Groups 1 to 18). Rhodium, ruthenium, and iridium are preferably the metals of Groups 8 to 10 of the periodic table or the central metal of the metal complex. One kind of these metal complexes may be used, or two or more kinds of complexes of the same metal and different metals may be used in combination. The preferred content is in the range of 1 × 10 ⁻⁹ mol to 1 × 10 ⁻³ mol per mol of silver. These heavy metals and metal complexes and their addition methods are described in JP-A-7-225449 and JP-A-11-65021, paragraph numbers 0018 to 002.
4, paragraph No. 0227 of JP-A-11-119374
０２0240.

Further, metal atoms (for example, [Fe (C)) which can be contained in the silver halide grains used in the present invention.
N) ₆ ] ^4- ), desalting and chemical sensitization of silver halide emulsions are described in paragraph No. 00 of JP-A-11-84574.
46-0050, Paragraph Nos. 0025-0031 of JP-A-11-65021, and Paragraph Nos. 0242-0250 of JP-A-11-119374.

Various gelatins can be used as the gelatin contained in the photosensitive silver halide emulsion used in the present invention. In order to maintain a good dispersion state of the photosensitive silver halide emulsion in the coating solution containing an organic silver salt, it is preferable to use low molecular weight gelatin having a molecular weight of 500 to 60,000. These low-molecular-weight gelatins may be used at the time of grain formation or at the time of dispersion after desalting, but are preferably used at the time of dispersion after desalting.

The sensitizing dye applicable to the present invention is a sensitizing dye capable of spectrally sensitizing silver halide grains in a desired wavelength region when adsorbed on silver halide grains, and has a spectral sensitivity suitable for the spectral characteristics of an exposure light source. The sensitizing dye to be used can be advantageously selected. The sensitizing dye and the method of addition are described in
Paragraph Nos. 0103 to 0109 of 1-65021,
JP-A-10-186572, compounds represented by the general formula (II), JP-A-11-119374, dyes represented by the general formula (I) and paragraph No. 0106, US Pat. No. 5,510,236 Description, No. 3,871,88
No. 7, the dye described in Example 5 of JP-A-2-9613.
No. 1, JP-A-59-48753, the dye disclosed in EP-A-0803764A1, page 19, line 38 to page 20, line 35, Japanese Patent Application No.
000-86865, Japanese Patent Application No. 2000-10256
No. 0 publication. These sensitizing dyes may be used alone or in combination of two or more. In the present invention, the time when the sensitizing dye is added to the silver halide emulsion is preferably after the desalting step and before coating, and more preferably after desalting and before the start of chemical ripening. The addition amount of the sensitizing dye in the present invention can be a desired amount in accordance with the sensitivity and the performance of fogging, but is preferably 10 ^-6 to 1 mol per mol of silver halide in the image forming layer, and more preferably. Is 10 ^-4 to 10 ^-1 mol.

According to the present invention, in order to improve the spectral sensitization efficiency,
Supersensitizers can be used. Examples of the supersensitizer used in the present invention include European Patent Publication No. 587,338, U.S. Pat.
873, 184, JP-A-5-341432, JP-A-11-109547 and JP-A-10-11154.
Compounds described in JP-A No. 3 and the like are exemplified.

The photosensitive silver halide grains in the present invention are preferably chemically sensitized by a sulfur sensitization method, a selenium sensitization method, or a tellurium sensitization method. Known compounds preferably used in the sulfur sensitization method, the selenium sensitization method, and the tellurium sensitization method include, for example, JP-A-7-12876.
Compounds described in JP-A No. 8 (1996) and the like can be used.
Particularly in the present invention, tellurium sensitization is preferable.
Compounds described in the literature described in paragraph No. 0030 of 1-65021 and compounds represented by formulas (II), (III) and (IV) in JP-A-5-313284 are more preferred.

In the present invention, chemical sensitization can be performed at any time after grain formation and before coating, and after desalting, (1) before spectral sensitization, (2) simultaneously with spectral sensitization, ( 3)
After spectral sensitization, there may be (4) just before coating. In particular, it is preferably performed after spectral sensitization. Sulfur used in the present invention, the amount of the selenium or tellurium sensitizer, silver halide grains to be used, but the chemical ripening condition and the like and, per 1 mol of silver halide 10 ^-8 to 10 ^-2 mol, preferably About 10 ^-7 to 10 ^-3 mol is used. The conditions for the chemical sensitization in the present invention are not particularly limited, but the pH is 5 to 8, the pAg is 6 to 11, and the temperature is 40 to 40.
It is about 95 ° C. A thiosulfonic acid compound may be added to the silver halide emulsion used in the present invention by the method described in EP-A-293,917.

The light-sensitive silver halide emulsion in the photothermographic material used in the present invention may be of one kind or two or more kinds (for example, those having different average grain sizes, those having different halogen compositions, those having different crystal habits). (Different ones, different chemical sensitization conditions). The gradation can be adjusted by using a plurality of photosensitive silver halides having different sensitivities. Japanese Patent Application Laid-Open No. 57-119 discloses a technique relating to these.
No. 341, No. 53-106125, No. 47-
3929, 48-55730 and 46-
Nos. 5187, 50-73627 and 57-
No. 150841 and the like. It is preferable that the difference in sensitivity be 0.2 logE or more in each emulsion.

The amount of the photosensitive silver halide added is 0.03 to 0.03, expressed as the amount of silver applied per m ^{2 of the} photothermographic material.
It is preferably 0.6 g / m ² , and 0.05 to 0.1 g / m ² .
4 g / m ² is more preferable, and 0.1 to 0.1 g / m ² .
The amount is most preferably 4 g / m ² , and the photosensitive silver halide is preferably 0.01 to 0.5 mol, more preferably 0.02 to 0.3 mol, per mol of the organic silver salt.

Regarding the mixing method and mixing conditions of the separately prepared photosensitive silver halide and organic silver salt, the prepared silver halide particles and organic silver salt were mixed with a high-speed stirrer, ball mill, sand mill, colloid mill, and vibrator. Mills, a method of mixing with a homogenizer, etc., or a method of preparing an organic silver salt by mixing photosensitive silver halide prepared at any timing during the preparation of the organic silver salt, etc. There is no particular limitation as long as the effect appears sufficiently. In addition, mixing two or more kinds of aqueous dispersions of organic silver salts and two or more kinds of aqueous dispersions of photosensitive silver salts is a preferable method for controlling photographic characteristics.

The preferable timing of addition of silver halide to the coating solution for the image forming layer is from 180 minutes to immediately before coating, preferably from 60 minutes to 10 seconds before coating. There is no particular limitation as long as the effect of (1) appears sufficiently. As a specific mixing method, a method of mixing in a tank in which the average residence time calculated from the addition flow rate and the amount of liquid sent to the coater is a desired time or
N. Harnby, MFEdwards, AWNienow, Translated by Koji Takahashi, "Liquid Mixing Technology", 8th edition of Nikkan Kogyo Shimbun, 1989.
There is a method using a static mixer or the like described in a chapter or the like.

The binder for the image-forming layer containing the organic silver salt may be any polymer; suitable binders are transparent or translucent, generally colorless, and include natural resins and polymers and copolymers, synthetic resins and polymers and Copolymers and other film-forming media such as gelatins, rubbers, poly (vinyl alcohol) s, hydroxyethyl celluloses, cellulose acetates, cellulose acetate butyrates, poly (vinyl pyrrolidone) s, casein, starch, poly (Acrylic acid)
, Poly (methyl methacrylic acid) s, poly (vinyl chloride) s, poly (methacrylic acid) s, styrene-maleic anhydride copolymers, styrene-acrylonitrile copolymers, styrene-butadiene copolymers, Poly (vinyl acetal) s (eg, poly (vinyl formal) and poly (vinyl butyral)), poly (esters),
Poly (urethane) s, phenoxy resins, poly (vinylidene chloride) s, poly (epoxides), poly (carbonates), poly (vinyl acetate) s, poly (olefins)
, Cellulose esters and poly (amides).
The binder may be coated from water or an organic solvent or an emulsion.

In the present invention, the image forming layer contains
In particular, when the composition is formed by coating using a coating solution containing 0% by mass or more of water and drying, and when the binder of the image forming layer is soluble or dispersible in an aqueous solvent (aqueous solvent). It is improved when the polymer latex has an equilibrium moisture content of 2% by mass or less at 25 ° C. and 60% relative humidity. The most preferred form has an ionic conductivity of 2.5 mS /
cm or less, and such a preparation method includes a method of purifying using a separation functional membrane after polymer synthesis.

The aqueous solvent in which the polymer is soluble or dispersible is water or a mixture of water and 70% by mass or less of a water-miscible organic solvent. Examples of the water-miscible organic solvent include alcohols such as methanol, ethanol, and propanol; cellosolves such as methyl cellosolve, ethyl cellosolve, and butyl cellosolve; ethyl acetate; and dimethylformamide. In the case of a system in which the polymer is not thermodynamically dissolved but exists in a so-called dispersed state,
Here, the term aqueous solvent is used. "25 ℃
The “equilibrium moisture content at a relative humidity of 60%” is defined as follows using the mass W1 of a polymer in a moisture-conditioning equilibrium under an atmosphere of 25 ° C. and a relative humidity of 60% and the mass W0 of a polymer in a completely dry state at 25 ° C. Can be expressed as {(W1-W0) / W0} × 100 (% by mass) For the definition and measurement method of the water content, for example, Polymer Engineering Course 14, Polymer Material Testing Method (Polymer Society, edited by Jinjinshokan)
Can be referred to. The equilibrium water content of the binder polymer used in the present invention at 25 ° C. and a relative humidity of 60% is preferably 2% by mass or less, more preferably 0.01 to 1.5% by mass, and still more preferably 0.02% by mass.
1% by mass is desirable.

In the present invention, a polymer dispersible in an aqueous solvent is particularly preferred. Examples of the dispersed state include a latex in which fine particles of a water-insoluble hydrophobic polymer are dispersed, and a dispersed state in which polymer molecules are dispersed in a molecular state or in the form of micelles. The average particle size of the dispersed particles is 1 to 50000 nm, more preferably 5 to 50000 nm.
A range of about 1000 nm is preferable. The particle size distribution of the dispersed particles is not particularly limited, and may have a wide particle size distribution or a monodispersed particle size distribution.

In the present invention, preferred examples of the polymer dispersible in an aqueous solvent include acrylic polymers, poly (esters), rubbers (for example, SBR resin), poly (urethane) s, poly (vinyl chloride) s, Hydrophobic polymers such as poly (vinyl acetate) s, poly (vinylidene chloride) s and poly (olefins) can be preferably used. These polymers may be a linear polymer, a branched polymer, a crosslinked polymer, a so-called homopolymer obtained by polymerizing a single monomer, or a copolymer obtained by polymerizing two or more types of monomers. In the case of a copolymer, it may be a random copolymer or a block copolymer. These polymers have a number average molecular weight of 5,000 to 1,000,000, preferably 10,000 to 200,000. If the molecular weight is too small, the mechanical strength of the image forming layer is insufficient, and if it is too large, the film-forming properties are poor, which is not preferable.

Specific examples of preferable polymer latex include the following. In the following, the raw material monomers are used, and the numerical value in parentheses is mass%, and the molecular weight is the number average molecular weight. P-1; -MMA (70) -EA (27) -MAA
(3) -Latex (molecular weight 37000) P-2; -MMA (70) -2EHA (20) -St
Latex of (5) -AA (5)-(molecular weight 4000
0) P-3; -St (50) -Bu (47) -MAA (3)
-Latex (molecular weight 45000) P-4; -St (68) -Bu (29) -AA (3)-
Latex (molecular weight 60000) P-5; -St (71) -Bu (26) -AA (3)-
Latex (molecular weight 60000) P-6; -St (70) -Bu (27) -IA (3)-
Latex (molecular weight 120,000) P-7; -St (75) -Bu (24) -AA (1)-
Latex (molecular weight 108000) P-8; -St (60) -Bu (35) -DVB (3)
Latex of -MAA (2)-(molecular weight 150,000) P-9; -St (70) -Bu (25) -DVB (2)
-AA (3)-latex (molecular weight 280000) P-10; -VC (50) -MMA (20) -EA (2
Latex of 0) -AN (5) -AA (5)-(molecular weight: 80000) P-11; -VDC (85) -MMA (5) -EA
Latex of (5) -MAA (5)-(molecular weight 6700
0) Latex of P-12; -Et (90) -MAA (10)-(molecular weight 12000) P-13; -St (70) -2EHA (27) -AA
Latex of (3) (molecular weight 130000) P-14; -MMA (63) -EA (35) -AA
Latex of (2) (molecular weight 33000)

Abbreviations of the above structures represent the following monomers.
MMA; methyl methacrylate, EA; ethyl acrylate, MAA; methacrylic acid, 2EHA; 2 ethylhexyl acrylate, St; styrene, Bu; butadiene, AA; acrylic acid, DVB;
C; vinyl chloride, AN; acrylonitrile, VDC; vinylidene chloride, Et; ethylene, IA; itaconic acid.

The polymer latex described above is also commercially available, and the following polymers can be used. Examples of acrylic polymers include Sebian A-463.
5,46583,4601 (manufactured by Daicel Chemical Industries, Ltd.), Nipol Lx811, 814, 82
1, 820, 857 (Nippon Zeon Co., Ltd.), etc.
Examples of poly (ester) s include FINETEX E
Examples of poly (urethane) s such as S650, 611, 675, and 850 (all manufactured by Dainippon Ink and Chemicals, Inc.), WD-size, and WMS (all manufactured by Eastman Chemical) include HYDRAN AP10, 20, 30, Examples of rubbers such as 40 (all manufactured by Dainippon Ink and Chemicals, Inc.) include LACSTAR 7310K, 3307B, 470
0H, 7132C (all manufactured by Dainippon Ink and Chemicals, Inc.),
Nipol Lx416, 410, 438C, 2507
(Nippon Zeon Co., Ltd.) and other poly (vinyl chloride)
Examples of poly (olefin) s include G351 and G576 (all manufactured by Zeon Corporation), and examples of poly (vinylidene chloride) s include L502 and L513 (all manufactured by Asahi Chemical Industry Co., Ltd.). For example, Chemipearl S
120, SA100 (all manufactured by Mitsui Petrochemical Co., Ltd.) and the like. These polymer latexes may be used alone, or may be used in combination of two or more as needed.

The polymer latex used in the present invention is particularly preferably a styrene-butadiene copolymer latex. The mass ratio of the styrene monomer unit to the butadiene monomer unit in the styrene-butadiene copolymer is preferably from 40:60 to 95: 5. The proportion of the copolymer of styrene monomer units and butadiene monomer units is 60 to 99% by mass.
It is preferred that The preferred molecular weight range is the same as described above. Styrene preferably used in the present invention
As the latex of butadiene copolymer, the above-mentioned P-
3-P-8, commercially available LACSTAR-3307
B, 7132C, Nipol Lx416 and the like.

The latex used in the present invention preferably has a glass transition temperature (Tg) in the range of 10 ° C. to 80 ° C., more preferably 20 ° C. to 60 ° C. When two or more latexes having different Tg are blended and used, the weight average Tg is preferably in the above range.

The image forming layer of the photothermographic material of the present invention may optionally contain a hydrophilic polymer such as gelatin, polyvinyl alcohol, methyl cellulose, hydroxypropyl cellulose, carboxymethyl cellulose and the like. The addition amount of these hydrophilic polymers is preferably 30% by mass or less, more preferably 20% by mass or less, based on the total binder of the image forming layer.

The image forming layer is preferably formed using a polymer latex. The amount of the binder in the image forming layer is such that the mass ratio of total binder / organic silver salt is 1/10 to 1/10.
The ratio is preferably 10/1, more preferably 1/5 to 4/1. Further, such an image forming layer is usually an image forming layer (photosensitive layer, emulsion layer) containing a photosensitive silver halide which is a photosensitive silver salt. The mass ratio of silver halide is preferably in the range of 400 to 5, more preferably 200 to 10. The total binder amount of the image forming layer is 0.2 to 30 g / m ² , more preferably 1 to 30 g / m ² .
A range of 15 g / m ² is preferred. A crosslinking agent for crosslinking and a surfactant for improving coating properties may be added to the image forming layer.

In the present invention, the solvent of the coating solution for the image forming layer of the photothermographic material (the solvent and the dispersion medium are collectively referred to as a solvent for simplicity) is preferably an aqueous solvent containing 30% by mass or more of water. . As a component other than water, any water-miscible organic solvent such as methyl alcohol, ethyl alcohol, isopropyl alcohol, methyl cellosolve, ethyl cellosolve, dimethylformamide, and ethyl acetate may be used. The water content of the solvent in the coating liquid is preferably 50% by mass or more, more preferably 70% by mass or more. Preferred examples of the solvent composition include water and water / methyl alcohol = 9.
0/10, water / methyl alcohol = 70/30, water / methyl alcohol / dimethylformamide = 80/15 /
5. Water / methyl alcohol / ethyl cellosolve = 85 /
10/5, water / methyl alcohol / isopropyl alcohol = 85/10/5, etc. (the numerical values are% by mass).

The antifoggants, stabilizers and stabilizer precursors which can be used in the present invention are described in
No. 62899, paragraph number 0070, European Patent Publication No. 0803764A1, page 20, line 57 to 21.
Patents described on page 7, line 7 may be mentioned. The antifoggant preferably used in the present invention is an organic halide, which is disclosed in JP-A-11-65021.
And Japanese Patent Application Laid-Open No. 11-11012. In particular, Japanese Patent Application No. 11-87
No. 297, an organic halogen compound represented by the formula (P), and JP-A-10-339934, a general formula (II)
The organic polyhalogen compound represented by is preferred.

Hereinafter, preferred organic polyhalogen compounds will be specifically described. Preferred polyhalogen compounds are compounds represented by the following general formula (III). General formula (III) Q- (Y) nC (Z ¹ ) (Z ² ) X The photothermographic material of the present invention contains an organic halogen compound represented by the general formula (III) for the purpose of preventing fog. Used.

In the formula (III), Q represents an alkyl group, an aryl group or a heterocyclic group which may have a substituent. The alkyl group represented by Q in the formula (III) is a linear, branched or cyclic alkyl group, preferably having 1 to 20 carbon atoms, more preferably 1 to 12 carbon atoms, and particularly preferably 1 to 6 carbon atoms. For example, methyl, ethyl, allyl, n
-Propyl, iso-propyl, sec-butyl, is
o-butyl, tert-butyl, sec-pentyl, i
Examples include so-pentyl, tert-pentyl, tert-octyl, 1-methylcyclohexyl, and the like. Preferably it is a tertiary alkyl group.

The alkyl group represented by Q may have a substituent, and any substituent may be used as long as it does not adversely affect photographic performance. Examples of the substituent include a halogen atom (fluorine atom). Atom, chloro atom, bromine atom or iodine atom), alkyl group, alkenyl group, alkynyl group, aryl group, heterocyclic group (including N-substituted nitrogen-containing heterocyclic group, for example, morpholino group), alkoxycarbonyl group, Aryloxycarbonyl group, carbamoyl group, imino group, imino group substituted by an N atom, thiocarbonyl group, carbazoyl group, cyano group, thiocarbamoyl group, alkoxy group, aryloxy group, heterocyclic oxy group, acyloxy group, (alkoxy Or aryloxy) carbonyloxy group, sulfonyloxy group, acylamide group, Ruhon'amido group, a ureido group,
Thioureido group, imide group, (alkoxy or aryloxy) carbonylamino group, sulfamoylamino group, semicarbazide group, thiosemicarbazide group, (alkyl or aryl) sulfonyluureido group, nitro group, (alkyl or aryl) sulfonyl group, sulfamoyl Group, a group containing a phosphate amide or a phosphate ester structure, a silyl group, a carboxyl group or a salt thereof,
Examples thereof include a sulfo group or a salt thereof, a phosphate group, a hydroxy group, and a quaternary ammonium group. These substituents may be further substituted with these substituents.

The aryl group represented by Q in formula (III) is a monocyclic or condensed-ring aryl group, preferably having 6 to 20 carbon atoms, more preferably 6 to 16 carbon atoms, particularly preferably 6 to 10 carbon atoms, A phenyl group or a naphthyl group is preferred. The aryl group represented by Q may have a substituent, and any substituent may be used as long as it does not adversely affect photographic performance. And the same groups as mentioned above.

The heterocyclic group represented by Q in the formula (III) includes a 5- or 7-membered saturated or unsaturated heterocyclic ring containing at least one heteroatom selected from the group consisting of nitrogen, oxygen and sulfur atoms. Those which are monocyclic or fused rings are preferred. Examples of heterocycles are preferably pyridine,
Quinoline, isoquinoline, pyrimidine, pyrazine, pyridazine, phthalazine, triazine, furan, thiophene, pyrrole, oxazole, benzoxazole, thiazole, benzothiazole, imidazole, benzimidazole, thiadiazole, triazole and the like, more preferably pyridine, quinoline, They are pyrimidine, thiadiazole and benzothiazole, particularly preferably pyridine, quinoline and pyrimidine. Q
The heterocyclic group represented by may have a substituent, and examples thereof include the same groups as the substituents of the alkyl group represented by Q in Formula 1.

Q is preferably a phenyl group, a naphthyl group, a quinolyl group, a pyridyl group, a pyrimidyl group, a thiadiazolyl group, a benzothiazolyl group, and particularly preferably a phenyl group, a naphthyl group, a quinolyl group, a pyridyl group, a pyrimidyl group. It is. As a substituent of Q, it may have a ballast group used in a photographic material to reduce diffusivity, an adsorptive group to a silver salt, or a group imparting water solubility, or polymerize with each other to form a polymer. Or the substituents may be bonded to each other to form a bis-type, tris-type, or tetrakis-type.

In the formula (III), Y represents a divalent linking group, preferably -SO _2- , -SO-, -CO-, and particularly preferably -SO _2- . In the formula (III), n represents 0 or 1, but is preferably 1. Z ¹ and Z ² each independently represent a halogen atom (eg, fluorine, chlorine, bromine, iodine, etc.), and it is most preferred that both Z ¹ and Z ² are bromine atoms.

X represents a hydrogen atom or an electron-withdrawing group.
The electron withdrawing group represented by X is a Hammett's substituent constant σ
_p is a substituent that can take a positive value, specifically, a cyano group, an alkoxycarbonyl group, an aryloxycarbonyl group, a carbamoyl group, a sulfamoyl group, an alkylsulfonyl group, an arylsulfonyl group, a halogen atom,
Examples include an acyl group and a heterocyclic group. X is preferably a hydrogen atom or a halogen atom, and most preferably a bromine atom.

Examples of the polyhalogen compound of the formula (III) include, for example, US Pat. No. 3,874,946, US Pat. No. 4,756,999, and US Pat.
No. 340,712, US Pat. No. 5,369,00.
0, U.S. Patent No. 5,464,737,
JP-A-50-137126 and JP-A-50-89020
JP-A-50-196624 and JP-A-59-572.
No. 34, JP-A-7-2781, 7-562
No. 1, No. 9-160164, No. 10-197
988, 9-244177, 9-24
Nos. 4178, 9-160167 and 9-3
19022, 9-258367, 9-
Nos. 265150, 9-319022 and 1
Nos. 0-197989, 11-242304, and Japanese Patent Application Nos. 10-181449 and 10-292.
Nos. 864, 11-90095, 11-8
Compounds described in 9773, 11-205330 and the like.

Specific examples of the polyhalogen compound represented by the general formula (III) are shown below, but the compounds usable in the present invention are not limited to these.

[0100]

Embedded image

[0101]

Embedded image

[0102]

Embedded image

In the present invention, as a method for incorporating an antifoggant into a photothermographic material, the method described in the above-mentioned method for containing a reducing agent can be mentioned, and an organic polyhalogen compound is also added as a dispersion of solid fine particles. Is preferred.

Other antifoggants include those described in
No. 65021, paragraph 0113, mercury (II)
Salts, benzoic acids described in paragraph No. 0114 of the same publication, Japanese Patent Application No. Hei.
A salicylic acid derivative represented by the formula (Z) in the specification of Japanese Patent Application No. 1-87297, a formula (S) in the specification of Japanese Patent Application No. 11-23995.
Formalin scavenger compound represented by the formula:
The triazine compound according to claim 9 of 1-352624, and the general formula (III) of JP-A-6-11791.
A compound represented by the formula: 4-hydroxy-6-methyl-1,
3,3a, 7-tetrazaindene and the like.

In the present invention, the photothermographic material is fog-proof.
It may contain an azolium salt for the purpose of stopping. Azori
The um salt is described in JP-A-59-193449.
A compound represented by the general formula (XI):
No. 581, JP-A-60-153039
And the compound represented by the general formula (II) described in
It is. Azolium salt can be used anywhere on photothermographic materials.
It may be added, but has an image forming layer as an added layer
Is preferably added to the image forming layer.
More preferably, When to add the azolium salt
May be performed in any process of coating solution preparation,
When adding to the layer, from preparation of organic silver salt to preparation of coating solution
Any process, but after the preparation of the organic silver salt and immediately before the coating
Is preferred. Azolium salts can be added by powder,
It may be performed by any method such as a liquid and a fine particle dispersion. Ma
Mixed with other additives such as sensitizing dyes, reducing agents,
May be added as a solution. In the present invention, azoliu
Any amount of salt may be added, but 1 mole of silver
1 × 10 per^-6Mol to 2 mol, preferably 1 × 10 ^-3
Mole to 0.5 mole is more preferred.

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. Paragraph No. 0 of JP-A-10-62899.
Nos. 067 to 0069, compounds represented by the general formula (I) in JP-A-10-186572, and paragraphs 0033 to 0052 as specific examples thereof, and European Patent Publication No. 08037.
No. 64A1, page 20, lines 36 to 56, and Japanese Patent Application No. 11-273670. Among them, mercapto-substituted heteroaromatic compounds are preferred.

In the photothermographic material of the present invention, it is preferable to add a toning agent.
No. 9, paragraphs 0054 to 0055, EP-A-0803764A1, page 21, pages 23 to 4.
Eight lines, described in JP-A-2000-35631, especially phthalazinones (phthalazinone, phthalazinone derivatives or metal salts; for example, 4- (1-naphthyl)
Phthalazinone, 6-chlorophthalazinone, 5,7-dimethoxyphthalazinone and 2,3-dihydro-1,4-
Phthalazine dione); a combination of phthalazinones and phthalic acids (eg, phthalic acid, 4-methylphthalic acid, 4-nitrophthalic acid and tetrachlorophthalic anhydride); phthalazines (phthalazine, phthalazine derivative or metal salt; eg, 4- (1-naphthyl) phthalazine, 6-isopropylphthalazine, 6-tert-butylflatazine, 6-chlorophthalazine, 5,7-dimethoxyphthalazine and 2,3-dihydrophthalazine); phthalazines and phthalic acids Are particularly preferable, and a combination of phthalazines and phthalic acids is particularly preferable.

The plasticizers and lubricants that can be used in the image forming layer are described in paragraph No. 0117 of JP-A-11-65021, and the ultra-high contrast agent for super-high contrast image formation, the method of addition and the amount thereof are the same. Publication No. 011
8, paragraph number 0136 of JP-A-11-223898
To 0193, compounds of formula (H), formulas (1) to (3), formulas (A) and (B) in Japanese Patent Application No. 11-87297, and general compounds described in Japanese Patent Application No. 11-91652. Formula (I
Compounds of II) to (V) (Specific compounds: Chemical formulas 21 to 2)
4) As for the contrast enhancement accelerator, JP-A-11-65021
Paragraph No. 0102, and Paragraph Nos. 0194-0195 of JP-A-11-223898.

In order to use formic acid or formate as a strong fogging substance, the side having the image forming layer containing photosensitive silver halide has a concentration of not more than 5 mmol, more preferably not more than 5 mmol per mol of silver.
It is preferable to contain it in an amount of not more than mmol.

Use of a super-high contrast agent in the photothermographic material of the present invention
If there is, the acid or its
Are preferably used in combination. Diphosphorus pentoxide
Examples of the acid or salt thereof formed by hydration include metaphosphoric acid.
(Salt), pyrophosphoric acid (salt), orthophosphoric acid (salt),
Acid (salt), tetraphosphoric acid (salt), hexametaphosphoric acid (salt)
And the like. Particularly preferably used five
Acids or salts thereof formed by hydration of diphosphorus oxide include:
Orthophosphoric acid (salt) and hexametaphosphoric acid (salt)
be able to. A specific salt is sodium orthophosphate
, Sodium dihydrogen orthophosphate, hexametaline
Sodium phosphate and ammonium hexametaphosphate
You. Use of acid or its salt formed by hydration of diphosphorus pentoxide
Dose (1m photothermographic material) ^TwoCoating amount per area)
The desired amount may be used according to the performance such as fog, but 0.1
~ 500mg / m^TwoIs preferred, and 0.5 to 100 mg /
m^TwoIs more preferred.

The photothermographic material according to the invention may be provided with a surface protective layer for the purpose of preventing adhesion of the image forming layer. The surface protective layer may be a single layer or a plurality of layers. Regarding the surface protective layer, see JP-A-11-65021.
No. 0119 to 0120.
Gelatin is preferred as the binder for the surface protective layer, but polyvinyl alcohol (PVA) is also preferred. As gelatin, inert gelatin (for example, Nitta Gelatin 750), phthalated gelatin (for example, Nitta Gelatin 801) and the like can be used. As the PVA, completely saponified PVA-105, partially saponified P
VA-205, PVA-335, MP-203 of modified polyvinyl alcohol (all trade names manufactured by Kuraray Co., Ltd.)
And the like. The amount of the polyvinyl alcohol applied per protective layer (per layer) (per 1 m ^{2 of} support) was 0.
3 to 4.0 g / m ² is preferred, and 0.3 to 2.0 g / m ²
Is more preferred.

In particular, when the photothermographic material of the present invention is used for printing in which dimensional change is a problem, it is preferable to use a polymer latex for the surface protective layer and the back layer.
For such polymer latex, see "Synthetic Resin Emulsion (edited by Tadashi Okuda and Hiroshi Inagaki, published by Polymer Publishing Association (1978))", "Application of Synthetic Latex (Takaaki Sugimura, Yasuo Kataoka, Soichi Suzuki, Keiji Kasahara, edited by Keiji Kasahara) Molecular publishing society (1993)), "Synthesis of synthetic latex (Souichi Muroi, published by Kobunshi Kankokai (1970))" and the like, and specifically, methyl methacrylate (33.5% by mass) / Ethyl acrylate (50% by weight) / latex of methacrylic acid (16.5% by weight) copolymer, methyl methacrylate (47.5% by weight) / butadiene (4
Latex of 7.5% by mass) / itaconic acid (5% by mass) copolymer, latex of ethyl acrylate / methacrylic acid copolymer, methyl methacrylate (58.9%)
Mass%) / 2-ethylhexyl acrylate (25.4
Mass%) / styrene (8.6 mass%) / 2-hydroxyethyl methacrylate (5.1 mass%) / latex of acrylic acid (2.0 mass%) copolymer, methyl methacrylate (64.0 mass%) / styrene Latex of (9.0% by mass) / butyl acrylate (20.0% by mass) / 2-hydroxyethyl methacrylate (5.0% by mass) / acrylic acid (2.0% by mass). Further, as a binder for the surface protective layer, a combination of a polymer latex described in Japanese Patent Application No. 11-6872, a technique described in paragraph Nos. 0021 to 0025 in Japanese Patent Application No. 11-143058, and a technology described in Japanese Patent Application No.
The technology described in paragraphs [0027] to [0028] of -6872 and the technology described in paragraphs [0023] to [0041] of JP-A-2000-19678 may be applied. The ratio of the polymer latex in the surface protective layer is preferably from 10 to 90% by mass of the total binder, particularly preferably from 20 to 80% by mass. The coated amount (per 1 m ^{2 of the} support) of the total binder (including the water-soluble polymer and the latex polymer) of the surface protective layer (per layer) is 0.3 to 5.0 g /
m ² is preferred, and 0.3 to 2.0 g / m ² is more preferred.

The preparation temperature of the coating solution for the image forming layer is from 30 to 65.
C is good, the more preferable temperature is 35C or more and less than 60C, and the more preferable temperature is 35 to 55C. The temperature of the coating solution for the image forming layer immediately after the addition of the polymer latex is preferably maintained at 30 to 65 ° C. Preferably, the reducing agent and the organic silver salt are mixed before the addition of the polymer latex.

The image forming layer is composed of one or more layers on a support. Organic silver salt,
It consists of a photosensitive silver halide, a reducing agent and a binder, and optionally contains additional materials such as toning agents, coating aids and other auxiliaries. When it comprises two or more layers, the first image-forming layer (usually a layer adjacent to the support) contains an organic silver salt and a photosensitive silver halide, and the second image-forming layer or both layers contain some. Other components must be included. The construction of a multicolor photothermographic material may include a combination of these two layers for each color, and all in a single layer as described in US Pat. No. 4,708,928. May be included. In the case of a multi-dye multi-color photosensitive heat-developable photographic material, each image forming layer is
Generally, they are kept separate from each other by using a functional or non-functional barrier layer between each imaging layer, as described in U.S. Pat. No. 4,460,681. .

Various dyes and pigments (for example, CI Pigment Blue 60, CI Pigme) are used in the image forming layer from the viewpoints of color tone improvement, prevention of interference fringe generation during laser exposure, and prevention of irradiation.
nt Blue 64, CI Pigment Blue 15: 6) can be used. These are described in International Publication WO 98/3632.
No. 2, Japanese Unexamined Patent Publication No. 10-268465, and No. 11-
It is described in detail in, for example, JP-A-338098.

In the photothermographic material of the present invention, an antihalation layer can be provided on the side farther from the light source than the image forming layer.

A photothermographic material generally has a non-photosensitive layer in addition to an image forming layer (photosensitive layer). The non-photosensitive layer
From the arrangement, (1) a protective layer provided on the image forming layer (on the side farther than the support); (2) an intermediate layer provided between a plurality of image forming layers or between the image forming layer and the protective layer; (3)
An undercoat layer provided between the image forming layer and the support,
(4) It can be classified as a back layer provided on the opposite side of the image forming layer. The filter layer is provided on the photothermographic material as the layer (1) or (2). The antihalation layer is provided on the photothermographic material as the layer (3) or (4).

The antihalation layer is disclosed in
JP-A-1-65021, paragraphs 0123 to 0124, JP-A-11-223898, JP-A-9-230531, JP-A-10-36695, and JP-A-10-10478.
No. 9, No. 11-231457, No. 11-35
No. 2625, No. 11-352626, and the like. The antihalation layer contains an antihalation dye having absorption at the exposure wavelength. When the exposure wavelength is in the infrared region, an infrared absorbing dye may be used, and in that case, a dye having no absorption in the visible region is preferable. When using a dye having absorption in the visible region to prevent halation, it is preferable that substantially no color of the dye remains after image formation, and a means for decoloring by the heat of heat development is used. It is particularly preferable to add a thermal decoloring dye and a base precursor to the non-photosensitive layer to function as an antihalation layer. These techniques are described in, for example, JP-A-11-231457.

The amount of the decolorizable dye is determined depending on the use of the dye. Generally, the optical density (absorbance) measured at the target wavelength is used in an amount exceeding 0.1. The optical density is preferably from 0.2 to 2. The amount of the dye used to obtain such an optical density is generally 0.00
It is about 1 to 1 g / m ² .

When the dye is decolored in this manner, the optical density after thermal development can be reduced to 0.1 or less. Two or more decolorizable dyes may be used in combination in a heat-decolorable recording material or a photothermographic material. Similarly, two or more base precursors may be used in combination. In thermal decoloring using such a decoloring dye and a base precursor,
When mixed with a base precursor as described in JP-A-11-352626, a substance (for example, diphenylsulfone, 4-chlorophenyl (phenyl) sulfone) which lowers the melting point by 3 ° C. or more can be used in combination with a heat discoloration property. It is preferred in that respect.

In the present invention, a colorant having an absorption maximum at 300 to 450 nm can be added for the purpose of improving the silver tone and the temporal change of the image. Such colorants are disclosed in JP-A-62-210458 and 63-104.
046, 63-103235, 63-103
JP-A-208846, JP-A-63-306436, JP-A-63-314535, JP-A No. 01-61745, and Japanese Patent Application No. 11-276751 describe it. Such a colorant is usually 0.1 mg / m
It is added in the range of ^{2 to 1} g / m ² , and the layer to be added is preferably a back layer provided on the side opposite to the image forming layer.

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

In the present invention, it is preferable to add a matting agent for improving the transportability.
JP-A-11-65021, paragraph numbers 0126 to 01
27. Matting agent: 1m photothermographic material
^When represented by the coating amount per ² , preferably 1 to 400
mg / m ^2, more preferably from 5 to 300 mg / m ^2. The matte degree of the image forming surface may be any value as long as no star dust failure occurs.
0 second is preferable, and 40 to 1500 second is particularly preferable. The Beck smoothness can be easily determined by Japanese Industrial Standards (JIS) P8119 “Smoothness test method of paper and paperboard with Beck tester” and TAPPI standard method T479.

In the present invention, the matting degree of the back layer is preferably such that Beck's smoothness is 10 to 1200 seconds.
It is preferably 800 seconds, more preferably 40 to 500 seconds. In the present invention, the matting agent is preferably contained in the outermost surface layer of the photothermographic material, a layer functioning as the outermost surface layer, or a layer close to the outer surface, and is contained in a layer acting as a so-called protective layer. Preferably. The back layer applicable to the present invention is described in JP-A-11-65021, paragraphs [0128] to [0128].
130.

The photothermographic material of the present invention preferably has a film surface pH before heat development of 6.0 or less, more preferably 5.5 or less. The lower limit is not particularly limited, but is about 3. For adjusting the film surface pH, it is preferable to use an organic acid such as a phthalic acid derivative, a nonvolatile acid such as sulfuric acid, or a volatile base such as ammonia from the viewpoint of reducing the film surface pH. In particular, ammonia is preferable for achieving a low film surface pH since ammonia is easily volatilized and can be removed before the application step and the heat development. The method of measuring the film surface pH is described in paragraph No. 0123 of Japanese Patent Application No. 11-87297.

A hardener may be used in each of the layers such as the image forming layer, the protective layer and the back layer. THJame is an example of a hardener
“THE THEORY OF THE PHOTOGRAPHIC PROCESS FOURTH
EDITION ”(published by Macmillan Publishing Co., Inc., 19
There are various methods described on pages 77 to 87, chromium alum, 2,4-dichloro-6-hydroxy-
In addition to s-triazine sodium salt, N, N-ethylenebis (vinylsulfoneacetamide), N, N-propylenebis (vinylsulfoneacetamide), polyvalent metal ions described on page 78 of the same book, U.S. Pat. No. 4,281,06
0, JP-A-6-208193, epoxy compounds such as U.S. Pat. No. 4,791,042, and vinylsulfone compounds such as JP-A-62-89048. It is preferably used.

The hardener is added as a solution, and the solution is added to the coating solution for the protective layer from 180 minutes to immediately before coating, preferably from 60 minutes to 10 seconds before coating. The mixing conditions are not particularly limited as long as the effects of the present invention are sufficiently exhibited. As a specific mixing method, a method of mixing in a tank in which the average residence time calculated from the addition flow rate and the amount of liquid sent to the coater is set to a desired time, or by N. Harnby, MFE Edwards, AW Nienow, translated by Koji Takahashi "Liquid mixing technology" (published by Nikkan Kogyo Shimbun, 198
9)), using a static mixer or the like described in Chapter 8 and the like.

For the surfactant applicable to the present invention, paragraph No. 0132 of JP-A No. 11-65021, for the solvent, paragraph No. 0133 of the same publication, and for the support, paragraph No. 0134 of the same publication, antistatic or conductive layer For paragraph No. 0135 of the same publication, paragraph No. 0136 of the same publication for a method of obtaining a color image, and paragraph No. 0061 of JP-A No. 11-84573 for a slipping agent.
0064 and Japanese Patent Application No. 11-106881 (paragraphs 0049 to 0062).

The transparent support is a polyester which has been subjected to a heat treatment at a temperature in the range of 130 to 185 ° C. in order to alleviate the internal strain remaining in the film at the time of biaxial stretching and to eliminate the heat shrinkage strain generated during the heat development processing. Particularly, polyethylene terephthalate is preferably used. In the case of a photothermographic material for medical use, the transparent support is made of a blue dye (for example,
It may be colored with dye-1) described in Examples of JP-A-240877, or may be uncolored. As the support, water-soluble polyester disclosed in JP-A-11-84574,
Styrene butadiene copolymer disclosed in JP-A-186565, paragraph No. 006 of Japanese Patent Application No. 11-106881.
It is preferable to apply an undercoating technique such as a vinylidene chloride copolymer of 3 to 0080. Further, regarding the antistatic layer or the undercoat, JP-A-56-143430, JP-A-56-143431, JP-A-58-62646, JP-A-56-120519, and JP-A-11-845.
No. 73, paragraphs 0040 to 0051, U.S. Pat. No. 5,575,957, JP-A-11-22389.
The technology described in paragraph Nos. 0078 to 0084 of Japanese Patent Publication No. 8 can be applied. The thickness of the support is not particularly limited, but is preferably 140 to 240 μm, more preferably 150 to 230 μm, and still more preferably 160 to 22 μm.
0 μm.

The photothermographic material is preferably of a monosheet type (a type capable of forming an image on the photothermographic material without using another sheet such as an image receiving material).

The photothermographic material may further contain an antioxidant, a stabilizer, a plasticizer, an ultraviolet absorber or a coating aid. Various additives are added to either the image forming layer or the non-photosensitive layer. About them, WO98 / 36322, European Patent Publication EP
No. 803764A1, JP-A-10-186567, and JP-A-10-18568 can be referred to.

The photothermographic material of the present invention may be applied by any method. Specifically, extrusion coating, slide coating, curtain coating, dip coating, knife coating,
Flow coating or US Pat. No. 2,681,2
Various coating operations are used, including extrusion coating using a hopper of the type described in U.S. Pat.
“LIQUID FIL” by ephen F. Kistler and Peter M. Schweizer
M COATING ”(CHAPMAN & HALL, 1997) 39
Extrusion coating or slide coating described on pages 9 to 536 is preferably used, and particularly preferably slide coating is used. An example of the shape of a slide coater used for slide coating is shown in FIG. In one. If desired, the method described in the same book, pages 399 to 536, U.S. Pat. No. 2,761,791 and British Patent No. 83
Two or more layers can be coated simultaneously by the method described in US Pat. No. 7,095.

The coating solution for the image forming layer in the present invention is preferably a so-called thixotropic fluid. The thixotropic property refers to a property in which the viscosity decreases as the shear rate increases. Any device may be used for measuring the viscosity, but RF manufactured by Rheometrics Far East Co., Ltd.
S fluid spectrometer is preferably used,
Measured at 5 ° C. Here, the viscosity of the coating solution for the image forming layer in the present invention at a shear rate of 0.1 S ^-1 is 400 to ¹ .
It is preferably from 0.00000 mPa · s, and more preferably from 500 to 20,000 mPa · s. Further, at a shear rate of 1000 S ⁻¹ , the pressure is preferably ¹ to 200 mPa · s, more preferably 5 to 80 mPa · s.

Various systems expressing thixotropy are known, and are described in “Lecture / Rheology”, edited by Polymer Publishing Association, Muroi,
It is described in Morino co-authored "Polymer Latex" (published by the Society of Polymer Publishing). In order for a fluid to exhibit thixotropic properties, it is necessary to contain a large amount of solid fine particles.
In order to enhance the thixotropic property, it is effective to include a thickened linear polymer, to increase the aspect ratio of the contained solid fine particles in an anisotropic shape, to use an alkali thickener, and to use a surfactant.

Techniques that can be used for the photothermographic material of the present invention include those described in European Patent Publication EP803676A1.
Publication No. 883022A1, International Publication WO98
/ 36322, JP-A-56-62648,
JP-A-58-62644, JP-A-9-281637, JP-A-9-297367, and JP-A-9-304869
Gazettes, JP-A-9-31405, and JP-A-9-32986
No. 5, No. 10-10669, No. 10-628
No. 99, No. 10-69023, No. 10-18
Nos. 6568 and 10-90823 and 10-908.
No. 171063, No. 10-186565, No. 10-186567, No. 10-186569 to No. 10-186572, No. 10-19797
No. 4, No. 10-197982, No. 10-19
No. 7983, No. 10-197985 to No. 10
-197987, 10-207001,
JP-A-10-207004, JP-A-10-221807, JP-A-10-282601, and JP-A-10-2888
No. 23, 10-288824, 10-3
07365, 10-312038, 1
JP-A-339934, JP-A-11-7100, JP-A-11-15105, JP-A-11-24200,
JP-A-11-24201, JP-A-11-30832, JP-A-11-84574, JP-A-11-65021, JP-A-11-109547, and JP-A-11-1258
Nos. 80, 11-129629 and 11-1
Nos. 33536 to 11-133439, 1
1-1133542, 11-133543, 11-2323898, 11-35262
No. 7 is also cited.

The photothermographic material of the present invention may be developed by any method, but is usually developed by elevating the temperature of the photothermographic material exposed imagewise. The preferred development temperature is 80 to 250 ° C, more preferably 10 to 250 ° C.
0-140 ° C. The development time is preferably from 1 to 180 seconds, more preferably from 10 to 90 seconds, and from 10 to 40 seconds.
Seconds are particularly preferred.

As a method of thermal development, a plate heater method is preferable. The heat development method using a plate heater method is preferably a method described in JP-A-11-133572, and a visible image is obtained by bringing the heat-developable photosensitive material having a latent image formed thereon into contact with a heating means in a heat development section. A heat developing device, wherein the heating means comprises a plate heater,
A plurality of pressing rollers are provided to face each other along one surface of the plate heater, and the photothermographic material is passed between the pressing roller and the plate heater to perform thermal development. This is a heat developing device. The plate heater is divided into 2 to 6 stages, and the tip is 1 to 10 ° C.
It is preferable to lower the temperature. Such a method is also described in JP-A-54-30032, which makes it possible to exclude water and an organic solvent contained in a photothermographic material from the system, The change in the shape of the support of the photothermographic material due to the heating of the material can also be suppressed.

The photothermographic material of the present invention may be exposed by any method, but a laser beam is preferred as an exposure light source. As the laser beam according to the present invention, a gas laser (Ar ⁺ , He—Ne), a YAG laser, a dye laser, a semiconductor laser, or the like is preferable. Further, a semiconductor laser and a second harmonic generation element can be used.
Preferably, it is a gas or semiconductor laser emitting red to infrared light.

As a medical laser imager having an exposure section and a heat development section, there is a Fuji Medical Dry Laser Imager FM-DPL.
Regarding FM-DPL, Fuji Medical Review No.
8, pages 39 to 55, and it goes without saying that those techniques are applied as a laser imager for the photothermographic material of the present invention. It can also be applied as a photothermographic material for a laser imager in an "AD network" proposed by Fuji Medical System as a network system conforming to the DICOM standard.

The photothermographic material of the present invention forms a black-and-white image by a silver image, and is used for medical diagnosis, photothermographic material for industrial photography, photothermographic material for printing, COM
It is preferably used as a photothermographic material for use.

[0141]

The present invention will be described more specifically with reference to the following examples and test examples. Materials, usage amounts, ratios, processing contents, processing procedures, and the like shown in the following examples can be appropriately changed without departing from the spirit of the present invention. Therefore, the scope of the present invention is not limited to the specific examples described below.

<Example 1><< Preparation of Undercoated Support >> (Preparation of PET Support) Using terephthalic acid and ethylene glycol, the intrinsic viscosity IV = 0.66 (phenol / tetrachloroethane) according to a conventional method. = 25 in 6/4 (mass ratio)
(Measured in ° C.). After pelletizing this 1
It was dried at 30 ° C. for 4 hours, melted at 300 ° C., extruded from a T-die, and quenched to prepare an unstretched film having a thickness of 175 μm after heat setting. This was longitudinally stretched 3.3 times using rolls having different peripheral speeds, and then transversely stretched 4.5 times using a tenter. The temperatures at this time were 110 ° C. and 130 ° C., respectively. After this, 240 ° C
After heat setting for 20 seconds, the film was relaxed 4% in the horizontal direction at the same temperature. After slitting the chuck part of the tenter,
Knurling both ends, winding at 4kg / cm ²
A roll having a thickness of 175 μm was obtained.

(Surface Corona Treatment) Using a solid state corona treatment machine 6KVA model manufactured by Pillar Co., both surfaces of the support were treated at room temperature at 20 m / min. From the current and voltage readings at this time, 0.375 kV was applied to the support.
-It turned out that the processing of A * minute / m < ² > was performed.
The processing frequency at this time is 9.6 kHz, and the electrode and the dielectric
The gap clearance of the shell was 1.6 mm.

(Preparation of Undercoating Support) (1) Preparation of Coating Solution for Undercoating Layer Formulation 1 (for undercoating layer on the image forming layer side) Pesresin A-515GB manufactured by Takamatsu Oil Co., Ltd. (30% by mass solution) 234 g polyethylene glycol Monononyl phenyl ether (average ethylene oxide number = 8.5, 10% by mass solution) 21.5 g MP-1000 (fine polymer particles, average particle diameter 0.4 μm) manufactured by Soken Chemical Co., Ltd. 0.91 g distilled water 744 ml

Formulation 2 (for back surface first layer) Styrene-butadiene copolymer latex 158 g (solid content 40% by mass, styrene / butadiene mass ratio = 68/32) 2,4-dichloro-6-hydroxy-S- Triazine sodium salt (8 mass% aqueous solution 20 g sodium lauryl benzene sulfonate (1 mass% aqueous solution) 10 ml distilled water 854 ml

Formulation 3 (for the back surface side second layer) SnO ₂ / SbO (9/1 mass ratio) (average particle size 0.038 μm, 17 mass% dispersion) 84 g gelatin (10 mass% aqueous solution) 89.2 g 8.6 g Metrolose TC-5 (2 mass% aqueous solution) manufactured by Shin-Etsu Chemical Co., Ltd. MP-1000 0.01 g manufactured by Soken Chemical Co., Ltd. 1 mass% aqueous solution of sodium dodecylbenzenesulfonate 10 ml NaOH (1 mass%) 6 ml Proxel (Manufactured by ICI) 1ml distilled water 805ml

(Preparation of undercoat support) The thickness of 175 μm
m of the biaxially stretched polyethylene terephthalate support was subjected to the above-mentioned corona discharge treatment, and then the undercoating coating liquid formulation 1 was coated on one side (image forming layer side) with a wire bar at a wet application amount of 6.6 ml / m ^2. (Per side) and dried at 180 ° C. for 5 minutes. Then, the undercoating liquid formulation 2 was applied to the back surface (back surface) with a wire bar so that the wet application amount was 5.7 ml / m ^2. And dried at 180 ° C. for 5 minutes. Further, the undercoating coating liquid formulation 3 was coated on the back surface (back surface) with a wire bar so that the wet coating amount was 7.7 ml / m ^2, and
After drying at 0 ° C. for 6 minutes, an undercoat support was prepared.

<< Preparation of Back Surface Coating Liquid >> (Preparation of Solid Fine Particle Dispersion (a) of Base Precursor)
64 g of the base precursor compound 11, 28 g of diphenyl sulfone, and a surfactant Demol N manufactured by Kao Corporation
10 g was mixed with 220 ml of distilled water, and the mixed solution was dispersed in beads using a sand mill (1/4 Gallon sand grinder mill, manufactured by Imex Co., Ltd.) to obtain a solid fine particle dispersion of a base precursor compound having an average particle diameter of 0.2 μm. (A) was obtained.

(Preparation of Dye Solid Fine Particle Dispersion) 9.6 g of cyanine dye compound 13 and 5.8 g of sodium p-dodecylbenzenesulfonate were mixed with 305 ml of distilled water, and the mixture was subjected to a sand mill (1/4 Gallon sand grinder mill). The dispersion was carried out using beads (manufactured by IMEX Co., Ltd.) to obtain a dye solid fine particle dispersion having an average particle diameter of 0.2 μm.

(Preparation of Anti-Halation Layer Coating Solution) 17 g of gelatin, 9.6 g of polyacrylamide, 70 g of solid fine particle dispersion (a) of the above base precursor, 56 g of the above solid fine particle dispersion of dye, monodispersed polymethyl methacrylate fine particles (average) Particle size 8 μm) 1.5 g, Benzoisothiazolinone 0.03 g, Polyethylene sodium sulfonate 2.2 g, Blue dye compound 14 0.2 g,
3.9 g of yellow dye compound 15 and 844 ml of water were mixed to prepare an antihalation layer coating solution.

(Preparation of Back Surface Protective Layer Coating Solution)
The mixture was kept at 0 ° C., and gelatin 50 g, polystyrene sodium sulfonate 0.2 g, N, N-ethylenebis (vinylsulfone acetamide) 2.4 g, tert-octylphenoxyethoxyethaneethane sodium 1 g,
Benzoisothiazolinone 30 mg, N-perfluorooctylsulfonyl-N-propylalanine potassium salt 3
7 mg, polyethylene glycol mono (N-perfluorooctylsulfonyl-N-propyl-2-aminoethyl) ether [average degree of polymerization of ethylene oxide 15]
0.15 g, C ₈ F ₁₇ SO ₃ K 32 mg, C ₈ F ₁₇ SO ₂ N
_{(C 3 H 7) (CH} 2 CH 2 O) 4 (CH 2) 4 -SO 3 Na6
4 mg, 8.8 g of acrylic acid / ethyl acrylate copolymer (copolymerization mass ratio 5/95), 0.6 g of Aerosol OT (manufactured by American Cyanamid Co.), 1.8 g of liquid paraffin emulsion as liquid paraffin, 950m of water
to obtain a back surface protective layer coating solution.

<< Preparation of Silver Halide Emulsion 1 >> Distilled Water 14
To 21 ml, 3.1 ml of a 1% by weight potassium bromide solution was added, and 3.5 ml of 0.5 mol / L sulfuric acid was further added.
While stirring the solution to which 31.7 g of phthalated gelatin was added in a stainless steel reaction bottle, the solution temperature was maintained at 34 ° C., solution A prepared by adding distilled water to 22.22 g of silver nitrate and diluting to 95.4 ml and potassium bromide. 15.9 g with distilled water to capacity 9
Solution B diluted to 7.4 ml was added at a constant flow rate over 45 seconds. Thereafter, 10 ml of a 3.5% by mass aqueous solution of hydrogen peroxide was added, and 1 ml of benzimidazole
10.8 ml of a 0% by mass aqueous solution was added. Further, a solution C obtained by adding distilled water to 31.86 g of silver nitrate to 317.5 ml and a solution D obtained by diluting 45.8 g of potassium bromide to a volume of 400 ml with distilled water were used.
The whole amount was added over 0 minutes, and solution D was added by a controlled double jet method while maintaining the pAg at 8.1. Solution C and Solution D were prepared by adding potassium hexachloride iridate (III) so as to be 1 × 10 ^-4 mol per mol of silver.
Was added 10 minutes after the start of the addition. Also,
Five seconds after the completion of the addition of the solution C, an aqueous solution of potassium iron (II) hexacyanide was added in an amount of 3 × 10 ^-4 mol per mol of silver. The pH was adjusted to 3.8 using sulfuric acid at a concentration of 0.5 mol / L.
, The stirring was stopped, and a settling / desalting / water washing step was performed. P with 1 mol / L sodium hydroxide
The pH was adjusted to 5.9 to prepare a silver halide dispersion having a pAg of 8.0.

While stirring the above silver halide dispersion, 3
While maintaining the temperature at 8 ° C., 5 ml of a 0.34 mass% 1,2-benzisothiazolin-3-one methanol solution was added,
Forty minutes later, a methanol solution of the spectral sensitizing dye A was added at 1 × 10 ⁻³ mol per mol of silver, and the temperature was raised to 47 ° C. one minute later. Twenty minutes after the temperature rise, 7.6 × 10 ^-5 sodium benzenethiosulfonate was added to 1 mol of silver in a methanol solution.
After 5 minutes, 1.9 × 10 ^-4 mol of tellurium sensitizer B was added per mol of silver with a methanol solution, and the mixture was aged for 91 minutes. 1.3 ml of a 0.8% by weight methanol solution of N, N′-dihydroxy-N ″ -diethylmelamine was added, and after a further 4 minutes, 5-methyl-2-mercaptobenzimidazole was added to the methanol solution at a concentration of 3 per mole of silver. .
7 × 10 ^-3 mol and 1-phenyl-2-heptyl-5
Mercapto-1,3,4-triazole was added in a methanol solution at 4.9 × 10 ⁻³ mol per mol of silver to prepare a silver halide emulsion 1. The grains in the prepared silver halide emulsion were pure silver bromide grains having an average sphere equivalent diameter of 0.046 μm and a variation coefficient of the equivalent sphere diameter of 20%. The particle size and the like were determined from the average of 1000 particles using an electron microscope. The {100} plane ratio of the particles was determined to be 80% using the Kubelka-Munk method.

<< Preparation of Silver Halide Emulsion 2 >> In the preparation of silver halide emulsion 1, the liquid temperature at the time of grain formation was set at 34 ° C. for 4 hours.
The temperature was changed to 9 ° C., and the addition time of solution C was changed to 30 minutes to remove potassium hexacyanoferrate (II).
A silver halide emulsion 2 was prepared. Precipitation / desalting / washing / dispersion was carried out in the same manner as in silver halide emulsion 1. Further, the addition amount of the spectral sensitizing dye A was 7.5 × 10 ^-4 mol per mol of silver, and the addition amount of the tellurium sensitizer B was 1.1 × 10 ⁴ mol per mol of silver.
^10-4 mol, 1-phenyl-2-heptyl-5-mercapto-1,3,4-triazole was changed to 3.3 × 10 ^-3 mol per mol of silver, in the same manner as in Emulsion 1. Spectral sensitization, chemical sensitization and 5-methyl-2-mercaptobenzimidazole, 1-phenyl-2-heptyl-5
Adding mercapto-1,3,4-triazole,
Thus, a silver halide emulsion 2 was obtained. The emulsion grains of the silver halide emulsion 2 were pure silver bromide cubic grains having an average equivalent sphere diameter of 0.080 μm and a variation coefficient of the equivalent sphere diameter of 20%.

<< Preparation of Silver Halide Emulsion 3 >> In the preparation of silver halide emulsion 1, the liquid temperature during grain formation was set at 34 ° C.
Except that the temperature was changed to 7.degree.
Was prepared. Further, precipitation / desalting / washing / dispersion / dispersion was carried out in the same manner as in silver halide emulsion 1. The spectral sensitizing dye A was added as a solid dispersion (aqueous gelatin solution) in an amount of 6 per mole of silver.
× 10 ^-3 mol, except for changing the amount of the tellurium sensitizer B was changed to 1 mole of silver per 5.2 × 10 ^-4 mol in the same manner as Emulsion 1, to obtain a silver halide emulsion 3. The emulsion grains of the silver halide emulsion 3 were pure silver bromide cubic grains having an average sphere equivalent diameter of 0.038 μm and a coefficient of variation of the equivalent sphere diameter of 20%.

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<< Preparation of Silver Halide Mixed Emulsion A for Coating Solution >> 70% by mass of silver halide emulsion 1, 15% by mass of silver halide emulsion 2 and 15% by mass of silver halide emulsion 3 were dissolved. Zolium iodide was added as a 1% by mass aqueous solution in an amount of 7 × 10 ⁻³ mol per mol of silver.

<< Preparation of Dispersion of Fatty Acid Silver >> Behenic acid (Edenor C22-85R, manufactured by Henkel) 87.6 k
g, 423 L of distilled water, 49.2 L of a 5 mol / L aqueous NaOH solution, and 120 L of tert-butanol were mixed and reacted at 75 ° C. for 1 hour with stirring to obtain a sodium behenate solution. Separately, an aqueous solution 2 of 40.4 kg of silver nitrate
06.2 L (pH 4.0) was prepared and kept at 10 ° C. A reaction vessel containing 635 L of distilled water and 30 L of tert-butanol was kept at 30 ° C., and while stirring, the whole amount of the sodium behenate solution and the whole amount of the silver nitrate aqueous solution were supplied at constant flow rates of 93 minutes, 15 seconds and 90 minutes, respectively. And added. At this time, only the silver nitrate aqueous solution was added for 4 minutes after the start of the silver nitrate aqueous solution addition, and then the addition of the sodium behenate solution was started, and only the sodium behenate solution was added for 14 minutes and 15 seconds after the addition of the silver nitrate aqueous solution was completed. I was doing it. At this time, the temperature inside the reaction vessel was 30 ° C.
The external temperature was controlled so that the liquid temperature became constant. Also, the piping for the addition system of the sodium behenate solution
The temperature was kept by steam tracing, and the steam opening was adjusted so that the liquid temperature at the outlet at the tip of the addition nozzle became 75 ° C. The piping of the silver nitrate aqueous solution addition system was kept warm by circulating cold water outside the double pipe. The addition position of the sodium behenate solution and the addition position of the aqueous silver nitrate solution were arranged symmetrically with respect to the stirring axis, and were adjusted to a height such that they did not come into contact with the reaction solution. After completion of the addition of the sodium behenate solution, the mixture is left to stir at the same temperature for 20 minutes,
The temperature was lowered to 25 ° C. Thereafter, the solid content was separated by suction filtration, and the solid content was washed with water until the conductivity of the filtered water became 30 μS / cm. Thus, a fatty acid silver salt was obtained. The obtained solid content was stored as a wet cake without drying.

The morphology of the obtained silver behenate particles was evaluated by electron microscopic photographing. The average value was a = 0.14 μm.
m, b = 0.4 μm, c = 0.6 μm, an average aspect ratio of 5.2, an average equivalent sphere diameter of 0.52 μm, and a flake-like crystal having a sphere equivalent diameter variation coefficient of 15%. (A, b, c are prescribed in the text) A wet cake having a dry solid content of 100 g is added to polyvinyl alcohol (trade name: PVA-21).
7) 7.4 g and water were added to make the total amount 385 g, and the mixture was pre-dispersed with a homomixer. Next, the pre-dispersed stock solution is dispersed in a dispersing machine (trade name: Microfluidizer M
-110S-EH, manufactured by Microfluidics International Corporation, using G10Z interaction chamber) at a pressure of 1750 kg / cm ²
And treated three times to obtain a silver behenate dispersion. The cooling operation is performed by installing coiled heat exchangers before and after the interaction chamber and adjusting the temperature of the refrigerant.
The dispersion temperature was set at 0 ° C.

<< Preparation of 25% by Mass Dispersion of Reducing Agent >>
10 kg of 1-bis (2-hydroxy-3,5-dimethylphenyl) -3,5,5-trimethylhexane and modified polyvinyl alcohol (manufactured by Kuraray Co., Ltd., Poval MP
16 kg of water was added to 10 kg of the 20% by mass aqueous solution of 203) and mixed well to form a slurry. This slurry was sent by a diaphragm pump, and a horizontal sand mill filled with zirconia beads having an average diameter of 0.5 mm (UVM-
2: 3 hours and 30 minutes by using IMEX Co., Ltd., and 0.2 g of benzoisothiazolinone sodium salt and water were added to adjust the concentration of the reducing agent to 25% by mass. I got something. The reducing agent particles contained in the reducing agent dispersion thus obtained had a median diameter of 0.42 μm and a maximum particle diameter of 2.0 μm or less. The obtained reducing agent dispersion was filtered through a polypropylene filter having a pore size of 10.0 μm to remove foreign substances such as dust, and stored.

<< Preparation of 25% by Mass Dispersion of Reducing Agent Complex >>
2,2-methylenebis- (4-ethyl-6-tert-
16 kg of water was added to 10 kg of a 1: 1 complex of butylphenol) and triphenylphosphine oxide and 10 kg of a 20% by mass aqueous solution of a modified polyvinyl alcohol (manufactured by Kuraray Co., Ltd., Poval MP203), and mixed well to form a slurry. This slurry is fed by a diaphragm pump, and a horizontal sand mill (UVM-2: IMEX Co., Ltd.) filled with zirconia beads having an average diameter of 0.5 mm.
), And 0.2 g of benzoisothiazolinone sodium salt and water were added to adjust the concentration of the reducing agent to 25% by mass to obtain a reducing agent complex dispersion. The reducing agent complex particles contained in the thus obtained reducing agent complex dispersion had a median diameter of 0.46 μm and a maximum particle diameter of 2.0.
μm or less. The resulting reducing agent complex dispersion has a pore size of 1
Filtration was performed with a 0.0 μm polypropylene filter to remove foreign substances such as dust, and stored.

<< Preparation of 10% by Mass Dispersion of Mercapto Compound >> 1-phenyl-2-heptyl-5-mercapto-
5 kg of 1,3,4-triazole and 20 of modified polyvinyl alcohol (Poval MP203 manufactured by Kuraray Co., Ltd.)
8.3 kg of water was added to 5 kg of a mass% aqueous solution and mixed well to form a slurry. The slurry was sent by a diaphragm pump, dispersed in a horizontal sand mill (UVM-2: manufactured by Imex Co., Ltd.) filled with zirconia beads having an average diameter of 0.5 mm for 6 hours, and then water was added thereto to obtain a concentration of the mercapto compound. Is adjusted to be 10% by mass.
A mercapto dispersion was obtained. The mercapto compound particles contained in the mercapto compound dispersion thus obtained had a median diameter of 0.40 μm and a maximum particle diameter of 2.0 μm or less. The resulting mercapto compound dispersion was filtered through a polypropylene filter having a pore size of 10.0 μm to remove foreign substances such as dust, and stored. Immediately before use, the hole diameter is 10
The mixture was filtered through a μm polypropylene filter.

<< Preparation of 20% by Mass Dispersion-1 of Organic Polyhalogen Compound >> Tribromomethylnaphthyl sulfone 5
and 2.5 kg of a 20% by mass aqueous solution of modified polyvinyl alcohol (Poval MP203 manufactured by Kuraray Co., Ltd.) and 20 kg of sodium triisopropylnaphthalenesulfonate.
213 g of a mass% aqueous solution and 10 kg of water were added and mixed well to form a slurry. The slurry was sent by a diaphragm pump and dispersed in a horizontal sand mill (UVM-2: manufactured by IMEX Co., Ltd.) filled with zirconia beads having an average diameter of 0.5 mm for 5 hours, and then benzoisothiazolinone sodium salt was added. 2 g and water are added to adjust the concentration of the organic polyhalogen compound to 20% by mass.
An organic polyhalogen compound dispersion was obtained. Organic polyhalogen compound particles contained in the polyhalogen compound dispersion thus obtained had a median diameter of 0.36 μm and a maximum particle diameter of 2.0.
μm or less. The obtained organic polyhalogen compound dispersion was filtered with a polypropylene filter having a pore size of 3.0 μm to remove foreign substances such as dust, and stored.

<< Preparation of 25% by mass dispersion of organic polyhalogen compound-2 >> 20% by mass of organic polyhalogen compound
Same as Dispersion-1, except that 5 kg of tribromomethylnaphthyl sulfone was used instead of tribromomethyl (4-
5 kg of (2,4,6-trimethylphenylsulfonyl) phenyl) sulfone was dispersed, diluted so that the organic polyhalogen compound became 25% by mass, and filtered. The organic polyhalogen compound particles contained in the organic polyhalogen compound dispersion thus obtained had a median diameter of 0.3.
8 μm, and the maximum particle size was 2.0 μm or less. The obtained organic polyhalogen compound dispersion was filtered with a polypropylene filter having a pore size of 3.0 μm to remove foreign substances such as dust, and stored.

<< Preparation of 26% by mass of organic polyhalogen compound dispersion-3 >> 20% by mass of organic polyhalogen compound
Similar to Dispersion-1, except that 5 kg of tribromomethylphenylsulfone was used instead of 5 kg of tribromomethylnaphthylsulfone,
kg and dispersed.
It diluted so that it might be set to mass%, and filtered. The organic polyhalogen compound particles contained in the organic polyhalogen compound dispersion thus obtained had a median diameter of 0.41 μm and a maximum particle diameter of 2.0 μm or less. The obtained organic polyhalogen compound dispersion was filtered with a polypropylene filter having a pore size of 3.0 μm to remove foreign substances such as dust, and stored. After storage, it was stored at 10 ° C. or lower until use.

<< Preparation of 25% by mass dispersion of organic polyhalogen compound-4 >> 20% by mass of organic polyhalogen compound
In the same manner as in Dispersion-1, except that 5 kg of tribromomethyl-3-pentanoylaminophenylsulfone is used instead of 5 kg of tribromomethylnaphthylsulfone, and dispersed, so that the organic polyhalogen compound becomes 25% by mass. Dilute and filter. The organic polyhalogen compound particles contained in the organic polyhalogen compound dispersion thus obtained had a median diameter of 0.41 μm and a maximum particle diameter of 2.0 μm or less. The obtained organic polyhalogen compound dispersion was filtered with a polypropylene filter having a pore size of 3.0 μm to remove foreign substances such as dust, and stored.

<< Preparation of 5% by mass solution of phthalazine compound >> 8 kg of modified polyvinyl alcohol MP203 manufactured by Kuraray Co., Ltd. was dissolved in 174.57 kg of water, and then 3.15 kg of a 20% by mass aqueous solution of sodium triisopropylnaphthalenesulfonate was added. 14.28 kg of a 70% by mass aqueous solution of 6-isopropylphthalazine was added to prepare a 5% by mass solution of 6-isopropylphthalazine.

<< Preparation of 20% by Mass Dispersion of Pigment >> CIPi
gment Blue 60 (64 g) and Kao Corporation's Demol N (6.4 g) were mixed with 250 g of water and mixed well to form a slurry. 800 g of zirconia beads with an average diameter of 0.5 mm
Was put into a vessel together with the slurry, and dispersed in a dispersing machine (1 / 4G sand grinder mill: manufactured by IMEX Co., Ltd.) for 25 hours to obtain a pigment dispersion. The pigment particles contained in the pigment dispersion thus obtained have an average particle size of 0.1.
It was 21 μm.

<< Preparation of 40% by mass of SBR latex >> The following SBR latex was diluted 10-fold with distilled water, and ultrafiltration (UF) purification module FS03-FC-
Using FUY03A1 (Daisen Membrane System Co., Ltd.), the product was diluted and purified until the ionic conductivity became 1.5 mS / cm, and Sandet-BL manufactured by Sanyo Chemical Co., Ltd.
Was added to be 0.22% by mass. Further, using NaOH and NH ₄ OH, Na ⁺ ion: NH ₄ ⁺ ion = 1:
The mixture was added to 2.3 (molar ratio) and adjusted to pH 8.4. The latex concentration at this time was 40% by mass. (SBR latex: -St (68) -Bu (2
9) Latex of -AA (3)-, Tg = 17 ° C) Average particle diameter 0.1 µm, concentration 45% by mass, equilibrium water content 0.6% by mass at 25 ° C and relative humidity 60%, ionic conductivity 4.2mS / Cm (Measurement of ionic conductivity using a conductivity meter CM-30S manufactured by Toa Denpa Kogyo Co., Ltd., measurement of a latex stock solution (40% by mass) at 25 ° C.), pH 8.2

<< Preparation of Coating Solution for Image Forming Layer >> 1.1 g of a 20% by mass dispersion of the pigment obtained above and a fatty acid silver dispersion 10 were prepared.
3 g, 5 g of a 20% by weight aqueous solution of polyvinyl alcohol PVA-205 (manufactured by Kuraray Co., Ltd.), 25 g of a 25% by weight dispersion of a reducing agent, and an organic polyhalogen compound dispersion-1,
-2, -3 at 5: 1: 3 (mass ratio), total amount of 16.3 g,
6.2 g of a 10% by weight dispersion of a mercapto compound, ultrafiltration (UF) purified and pH-adjusted SBR latex (T
g: 17 ° C.) 106 g of 40% by mass and 18 ml of a 5% by mass solution of a phthalazine compound were added, and immediately before coating, 10 g of a silver halide mixed emulsion A was well mixed and coated on an image forming layer (photosensitive layer, emulsion layer). The liquid was directly sent to the coating die at 70 ml / m ² and applied. The viscosity of the coating solution for the image forming layer was measured at 40 ° C. (No. 1 rotor, 60 rpm) at 85 ° C. using a B-type viscometer of Tokyo Keiki.
[MPa · s]. The viscosity of the coating solution at 25 ° C. using an RFS fluid spectrometer manufactured by Rheometrics Far East Co., Ltd.
1500, 220, 70, 40, 20 [mPa · s] at 1, 10, 100, and 1000 [1 / sec]
Met.

<< Preparation of Coating Solution for Intermediate Layer on Image Forming Surface >> Polyvinyl alcohol PVA-205 (manufactured by Kuraray Co., Ltd.)
4. 772 g of 0% by mass aqueous solution, 20% by mass dispersion of pigment
Aerosol OT was added to 226 g of 3 g of a 27.5 mass% liquid of methyl methacrylate / styrene / butyl acrylate / hydroxyethyl methacrylate / acrylic acid copolymer (copolymer mass ratio 64/9/20/5/2).
(American Cyanamid) 5% by weight aqueous solution
10.5 ml of a 20% by mass aqueous solution of diammonium phthalate, water was added to make a total amount of 880 g.
An intermediate layer coating solution was prepared by adjusting with NaOH so that H became 7.5, and the solution was fed to a coating die so as to be 10 ml / m ² . The viscosity of the coating solution was measured at 40 ° C. using a B-type viscometer (No.
It was 21 [mPa · s] with one rotor at 60 rpm.

<< Preparation of Coating Solution for First Layer of Image Forming Surface Protective Layer >>
64 g of inert gelatin was dissolved in water, and 27.5% by mass of methyl methacrylate / styrene / butyl acrylate / hydroxyethyl methacrylate / acrylic acid copolymer (copolymer mass ratio 64/9/20/5/2) latex was used.
80 g of the liquid, a 10% by mass methanol solution of phthalic acid
ml, 10% by weight aqueous solution of 4-methylphthalic acid 23m
1, 28 ml of sulfuric acid having a concentration of 0.5 mol / L, 5 ml of a 5% by mass aqueous solution of aerosol OT (manufactured by American Cyanamid), 0.5 g of phenoxyethanol and 0.1 g of benzoisothiazolinone were added to a total amount of 750 g. Water was added to make a coating solution, and a mixture of 26 ml of 4% by mass chromium alum immediately before coating with a static mixer was sent to a coating die at 18.6 ml / m ² . The viscosity of the coating solution is 40 ° C (N
o. It was 17 [mPa · s] with one rotor at 60 rpm.

<< Preparation of Coating Solution for Second Layer of Image Forming Surface Protective Layer >>
80 g of inert gelatin is dissolved in water, and 27.5% by mass of methyl methacrylate / styrene / butyl acrylate / hydroxyethyl methacrylate / acrylic acid copolymer (copolymer mass ratio 64/9/20/5/2) latex
Liquid 102 g, N-perfluorooctylsulfonyl-N
3.2% by weight of a 5% by weight solution of potassium propylalanine salt.
32 ml of a 2% by weight aqueous solution of polyethylene glycol mono (N-perfluorooctylsulfonyl-N-propyl-2-aminoethyl) ether [average degree of polymerization of ethylene oxide = 15], Aerosol OT (manufactured by American Cyanamid Co.) 23% of a 5% by mass solution of polymethyl methacrylate (average particle size 0.7 μm)
4 g, polymethyl methacrylate fine particles (average particle size: 4.
5 μm) 21 g, 1.6 g of 4-methylphthalic acid, 4.8 g of phthalic acid, 44 ml of 0.5 mol / L sulfuric acid, and 10 mg of benzoisothiazolinone were added with water so that the total amount became 650 g, and 4% by mass of chromium was added. Alum and 0.6
Immediately before coating, 445 ml of an aqueous solution containing 7% by mass of phthalic acid was mixed with a static mixer to obtain a surface protective layer coating solution, which was then sent to a coating die at 8.3 ml / m ² . The viscosity of the coating solution is B type viscometer 40 ° C
9 [mPa · s] at (No. 1 rotor, 60 rpm)
Met.

<< Heat-Developable Photosensitive Material-Preparation of Sample 101 >> On the back surface side of the undercoating support, an antihalation layer coating solution was coated with a solid fine particle dye having a solid content of 0.04 g / m 2.
² and the backside protective layer coating solution was simultaneously layer-coated so that the gelatin coating amount was 1.7 g / m ² .
It dried and the back layer was produced. On the surface opposite to the back surface, from the undercoat surface to the image forming layer (a silver halide coating amount of 0.1
4 g / m ² ), an intermediate layer, a protective layer first layer, and a protective layer second layer were simultaneously coated in order by a slide bead coating method to prepare a photothermographic material sample. The coating and drying conditions are as follows. The coating was performed at a speed of 160 m / min, and the gap between the tip of the coating die and the support was 0.10.
0.30 mm, and the pressure in the decompression chamber is 1
It was set lower by 96 to 882 Pa. The support was neutralized with ion wind before coating. In the subsequent chilling zone, the coating solution is cooled by air having a dry-bulb temperature of 10 to 20 ° C., and is then transferred in a non-contact type. It was dried with a dry air having a wet bulb temperature of 15 to 21 ° C. After drying, the humidity was controlled at 25 ° C. at a relative humidity of 40 to 60%, and the film surface was heated to 70 to 90 ° C. After heating, the film surface was cooled to 25 ° C. The matte degree of the prepared photothermographic material was 5% on the image forming layer surface side with Beck smoothness.
It was 50 seconds and the back surface was 130 seconds. Further, the pH of the film surface on the side of the image forming layer was measured and found to be 6.0.

<< Preparation of Photothermographic Material-Samples 102 to 110 >> The photothermographic material-sample 102 was prepared in the same manner as the photothermographic material-sample 101 except that the amount of the binder applied was changed as shown in Table 1. To 110 were produced.

<< Preparation of Photothermographic Material-Sample 111 >> Except that the yellow dye compound was removed from the photothermographic material-sample 101 after the antihalation coating by changing the coating solution of the image forming layer as follows. Is a photothermographic material in the same manner.
Sample 111 was prepared. (Preparation of coating solution for image forming layer) 1.1 g of a 20% by weight aqueous dispersion of the pigment obtained above, 103 g of a fatty acid silver dispersion, and 5 g of a 20% by weight aqueous solution of polyvinyl alcohol PVA-205 (manufactured by Kuraray Co., Ltd.) 26 g of a 25 mass% dispersion of the reducing agent complex, and organic polyhalogen compound dispersions-3 and -4.
: 1: 3 (mass ratio), total amount 8.2g, mercapto compound 10% dispersion 6.2g, ultrafiltration (UF) purified and pH adjusted SBR latex (-St (71) -Bu (2
6) Latex of -AA (3)-, Tg: 24 ° C) 40
106% by mass and 18 ml of a 5% by mass solution of a phthalazine compound were added.
The image forming layer coating liquid obtained by thoroughly mixing 10 g of the above was directly sent to a coating die at 70 ml / m ² ,
Applied.

<< Heat-Developable Photosensitive Material-Preparation of Samples 112 to 120 >> The heat-developable photosensitive material-sample 112 was prepared in the same manner as the heat-developable photosensitive material-sample 111 except that the amount of the binder applied was changed as shown in Table 1. To 120 were produced.

<< Evaluation >> (Evaluation of Water Content on Image Forming Layer Side) Evaluation was made by the method described in the embodiment of the present invention. In addition, about the measurement of the water content by the Karl Fischer method, Hiranuma automatic heating vaporization moisture measurement system AQS-720 (made by Hiranuma Sangyo Co., Ltd.) was used. (Evaluation of Amount of Solvent Contained) Evaluation was made by the method described in the embodiment of the present invention. In addition, about the measurement of the organic solvent by the gas chromatography method, the gas chromatograph GC-14A (made by Shimadzu Corporation) was used. (Evaluation of photographic performance) The photothermographic material was exposed and thermally developed (about 120 ° C.) using a Fuji Medical Dry Laser Imager FM-DPL (with a 660 nm semiconductor laser with a maximum output of 60 mW (IIIB)). The image was evaluated with a densitometer. (Evaluation of image preservability) Fuji Medical Dry Laser Imager FM-DP L (Max. 60 mW (IIIB)
After exposure and thermal development (approximately 120 ° C.) of the photothermographic material with a 660 nm output semiconductor laser), the material was stored for 24 hours under an illuminance of 1000 L under a fluorescent lamp in an environment of 30 ° C. and 70% relative humidity. The image was evaluated using a densitometer, and the difference between the image and the result obtained by the photographic performance evaluation method was calculated. Table 1 shows the results.

[0180]

[Table 1]

As shown in Table 1, the photothermographic material of the present invention was excellent in photographic performance (Dmin, sensitivity) and image storability. In addition, it has been found that since there is almost no residual solvent amount, no odor is generated in the heat development process, and the working environment is not adversely affected.

<Example 2><< Heat-developable photosensitive material-Preparation of sample 201 >> The photo-developable photosensitive material-sample was prepared in the same manner as the heat-developable photosensitive material-sample 102 except that the SBR latex was changed as shown in Table 2. 201-2
10 were produced and evaluated. Table 2 shows the results.

[0183]

[Table 2]

The results in Table 2 show that photographic performance and image storability deteriorate when the content of the solvent is out of the range of the present invention. In addition, when the content of the solvent is large, an odor is generated in the heat development process, and the organic solvent remains in the photothermographic material and is released to the atmosphere during the heat development process, which adversely affects the working environment. there were.
In contrast, the photothermographic material of the present invention is excellent in photographic performance and image storability, and does not adversely affect the working environment.

[0185]

According to the present invention, a photothermographic material excellent in photographic performance and image storability and having no adverse effect on the working environment can be obtained.

Claims (3)

[Claims] 1. A method according to claim 1, wherein at least one photosensitive silver halide, a non-photosensitive organic silver salt,
In a photothermographic material having at least one image forming layer containing a reducing agent and a binder for silver ions and at least one non-photosensitive layer, the entirety of the constituent layers on a support is water-containing. Rate 25 ° C, relative humidity 60
% Is 0.1 to 1.5%, and the content of the solvent is 0.0%.
A photothermographic material, wherein the content is from 01 to 50 ppm. 2. The ratio (a / b) of the water content (a) of the non-photosensitive layer to the water content (b) of the image forming layer is 0.06 to 6.
The photothermographic material according to claim 1, wherein 3. A method according to claim 1, wherein at least one photosensitive silver halide, a non-photosensitive organic silver salt,
In a photothermographic material having at least one image forming layer containing a reducing agent and a binder for silver ions and at least one non-photosensitive layer, the water content (a ) And the water content (b) of the image forming layer are 0.06 to 6 and the solvent content is 0.001 to 50 ppm.