JP2003255487A - Photothermographic imaging material - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a photothermographic imaging material having excellent photographic performance including high sensitivity and low fog, to provide a photothermographic imaging material inhibited from fogging due to print-out silver after development and to further provide a photothermographic imaging material excellent in raw stock preservability before development and image preservability after development and having little residual color and a stable color tone after development. <P>SOLUTION: In a photothermographic imaging material having on a support a photosensitive layer comprising photosensitive silver halide grains, an organic silver salt, a reducing agent and a binder, a benzoxazine compound or its polymer is contained. <P>COPYRIGHT: (C)2003,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a photothermographic image forming material for forming an image by heat development, and particularly to a photothermographic image capable of obtaining high sensitivity and low fog and excellent in raw storability. Regarding the forming material. Further, the present invention relates to a photothermographic image forming material which is excellent in storability of an image obtained after development and in which generation of printout silver is suppressed.

[0002]

2. Description of the Related Art In recent years, a photothermographic material that does not produce waste liquid associated with a wet process has been strongly desired in the fields of medical treatment and printing from the viewpoint of environmental protection and workability. There is a need in the art for photothermographic materials for photographic applications that are capable of forming images. These photothermographic materials are usually referred to as photothermographic image-forming materials because they are exposed imagewise and developed at a temperature of 80 ° C. or higher to form an image.

This type of photothermographic image-forming material has hitherto been irradiated toward a photosensitive layer containing a highly sensitive silver halide grain spectrally sensitized with a dye, an organic silver salt and a reducing agent, and the photosensitive layer. An irradiation prevention layer (hereinafter, also referred to as an AI layer) that prevents light from passing through without being absorbed and being irregularly reflected at the interface of the support, an intermediate layer, an adhesive layer, or the like, or a backing layer provided on the opposite side of the support (hereinafter, referred to as an AI layer). , BC), and a protective layer or the like for preventing scratches during handling on the photosensitive layer or on the BC layer.

Generally, a photothermographic image-forming material is easy to process because the image formation is completed only by post-exposure heat development, but since there is no fixing step, it is important to improve the storability of the image after development. Has become. In order to improve the storability after development, it is preferable to develop the image at a high temperature so that an image appears, but if the temperature is too high, fog is likely to occur and the sensitivity is lowered. Therefore, development is generally performed at a temperature of 120 ° C. ± 10 ° C.

The use of mercapto compounds for reducing fog is disclosed in JP-A-63-301037, JP-A-5-341432, JP-A-5-509182 and JP-A-2000-19681. . However, in all cases, the mercapto compound has a small effect of suppressing fog, has a limit in improving storage stability, and has a problem that it is difficult to obtain high sensitivity. Regarding the suppression of printed silver after development, it is preferable to use a phthalazine compound.
7132, 61-183642, JP-A-9-11
No. 4036, No. 9-258366, Special Table 10-50
8599, JP-A-10-339931, 11-4.
No. 9756, No. 11-218877, No. 11-223
900, JP-A 2000-10234, 2000-
Nos. 10232 and 2000-35630 are disclosed. Both are described to be improved in fog, sensitivity, concentration, storability, etc. by using phthalazine or an additive other than phthalazine, but it is preferable to use a benzoxazine compound or a polymer thereof. No mention is made of the effect when used in combination with the compound. A polyhalomethane compound is effective for suppressing bake-out silver after development.
77, 9-265150 and 9-31902.
No. 2 attempts to improve raw storability, image storability, color tone, suppression of printout silver and the like by specifying the structure, but it has not been sufficient. Attempts have been made to improve the cross-linking of the binder by improving the pH and the combined use of a cross-linking agent for improving the storability, but it was not sufficient.

[0006]

SUMMARY OF THE INVENTION The present invention has been made in view of the above circumstances, and a first object of the present invention is to provide a photothermographic image forming material excellent in high sensitivity and low fog in photographic performance. To do. The second object of the present invention is to
Another object of the present invention is to provide a photothermographic image forming material in which fogging due to printed silver after development is suppressed. A third object of the present invention is to provide a photothermographic image forming material which is excellent in raw storability before development and image storability after development, has little residual color after development, and has stable color tone. is there.

[0007]

The above object of the present invention can be achieved by the following constitutions.

1. Photosensitive silver halide grains on a support,
A photothermographic image forming material having a photosensitive layer containing an organic silver salt, a reducing agent and a binder, which comprises a benzoxazine compound or a polymer thereof.

2. The benzoxazine compound or a polymer thereof is represented by the general formula (1) or (2), or the general formula (3).
Alternatively, the photothermographic image-forming material as described in 1 above, which is a polymer of a benzoxazine compound represented by (4).

3. 3. The photothermographic image-forming material as described in 1 or 2 above, wherein the photosensitive layer or a layer adjacent to the photosensitive layer contains a phthalazine compound.

4. 4. The photothermographic image-forming material as described in any one of 1 to 3 above, wherein the photosensitive layer or a layer adjacent to the photosensitive layer contains a polyhalomethane compound.

5. 5. The photothermographic image forming material described in any one of 1 to 4 above, which contains a bisphenol compound in the photosensitive layer or a layer adjacent to the photosensitive layer.

6. Any of the above 1 to 5, wherein the crosslinking agent for crosslinking the binder of the photosensitive layer or a layer adjacent to the photosensitive layer is at least one selected from an isocyanate compound, a vinyl sulfone compound and an epoxy compound. The photothermographic image-forming material as described in 1 above.

The present invention will be described in detail below. The photothermographic image-forming material of the present invention is a photothermographic image-forming material having a photosensitive layer containing photosensitive silver halide grains, an organic silver salt, a reducing agent and a binder on a support, and a benzoxazine compound or a polymer thereof. One of the features is that it contains the body.

The photothermographic imaging materials of this invention are typically
A support having at least one photosensitive layer and a layer adjacent to the photosensitive layer, and having at least two layers.
It is preferable to include a BC layer provided on the opposite side of the photosensitive layer, a protective layer thereof, and the like. The photosensitive layer of the photothermographic image-forming material contains at least photosensitive silver halide grains which may be sensitized with a spectral sensitizing dye, and the photosensitive layer or an adjacent layer thereof contains an organic material serving as a silver source. A silver salt, a reducing agent for developing the silver salt to form a silver image, and a benzoxazine compound of the present invention or a polymer thereof are contained.

The photosensitive layer of the above-mentioned photothermographic image-forming material or a layer adjacent to the photosensitive layer preferably contains a polymer binder, a hydrophilic binder or a hydrophobic binder, which provides a field for a heat development reaction, More preferably, it contains an isocyanate compound, a vinyl sulfone compound, an epoxy compound or the like that cross-links and cures the binder. In the above photothermographic image forming material, an AI layer or a BC layer containing a dye for preventing irradiation or for preventing halation is provided if necessary.

The benzoxazine compound or its polymer, the phthalazine compound and the polyhalomethane compound contained in the photothermographic image-forming material of the present invention will be described below in order. The photosensitive silver halide grains contained in the photosensitive layer of the photothermographic image-forming material, the organic silver salt contained in the photosensitive layer or its adjacent layer, the reducing agent, and the high-concentration contained in the photosensitive layer or its adjacent layer. The molecular binder and the like will be described later in sequence.

The benzoxazine compound or polymer thereof of the present invention will be described. A benzoxazine compound is a compound having a benzoxazine ring having an oxazine ring having one nitrogen atom and one oxygen atom condensed with a benzene ring as a nucleus, and introducing various functional groups into the benzoxazine ring. Thereby, the characteristics of the photothermographic image forming material can be improved. As a group to be introduced into the benzoxazine ring, a substituent which improves photographic characteristics such as sensitivity, fog and contrast and storage stability can be introduced. Further, the benzoxazine ring of the benzoxazine compound can be easily opened to polymerize by applying heat, and a polymer of this benzoxazine compound can also be preferably used.

Preferred examples of the above-mentioned benzoxazine compound or a polymer thereof include the benzoxazine compound represented by the general formula (1) or (2) of the present invention, or the general formula (3) or (4). And a polymer of a benzoxazine compound represented by (hereinafter, also simply referred to as a benzoxazine compound of the present invention or a polymer thereof).

In the above general formulas (1) to (4), R
¹ , R ² and R ³ represent a hydrogen atom, a halogen atom, an alkyl group, a fluorinated alkyl group, an alkoxy group, a hydroxy group or a carboxyalkyl group, n represents an integer of 0 to 1000, and L ₁ and L ₂ represent It represents a divalent linking group. However, the case where R ¹ is a hydrogen atom is excluded.

R¹, R²And R³An alkyl group represented by
Are, for example, methyl group, ethyl group, butyl group,
Hydrocarbons having 1 to 25 carbon atoms such as octyl and dodecyl groups
Group, and examples of the halogen atom include fluorine.
Atom, chlorine atom, bromine atom, etc.
Or a chlorine atom is preferred. As the fluorinated alkyl group,
For example, monofluoromethyl group, difluoromethyl group, trifluoromethyl group
Fluoromethyl group, ethyl fluoride group, butyl fluoride group, etc.
Examples of the alkoxy group include methoxy group and ethoxy group.
Examples of carboxyalkyl groups such as groups and butoxy groups are
For example, carboxymethyl group, carboxyethyl group and
A carboxybutyl group etc. are mentioned. L ₁And L₂Table
Examples of the divalent linking group to be used include ethylene group and n
-Propylene group, iso-propylene group, dimethyl methyl
Examples thereof include a len group and a butylene group. n is 0 to 1000
Represents the integer. Preferred specific compound examples are shown below.
However, the compounds of the present invention are not limited to these.

[0022]

[Chemical 2]

[0023]

[Chemical 3]

[0024]

[Chemical 4]

The above-mentioned benzoxazine compound of the present invention or a polymer thereof is described in JP-A-11-25600.
9, JP-A-2000-178332, and JP-A-2000-1.
It can be synthesized with reference to the method described in No. 91775.

The benzoxazine compound of the present invention or the polymer thereof can be added according to a known addition method. It can be added by dissolving it in alcohols such as methanol and ethanol, ketones such as methyl ethyl ketone and acetone, polar solvents such as dimethyl sulfoxide and dimethylformamide, and the like. Also,
Fine particles having a size of 1 μm or less can be added by sand mill dispersion, jet mill dispersion, ultrasonic dispersion or homogenizer dispersion and then dispersed in water or an organic solvent. The addition amount is preferably in the range of 1/1000 to 60% by mass in the coating liquid, particularly preferably in the range of 1/100% to 30% by mass, and the addition amount is appropriately adjusted in this range. Can be used. The amount of the benzoxazine compound of the present invention or the polymer thereof used in the photothermographic image-forming material of the present invention is 10 ⁻⁶ mol to 10 ⁻² mol / m ^2.
It is preferably ² .

(Phthalazine Compound) The phthalazine compound according to the present invention can be obtained by introducing various substituents into the phthalazine ring. Preferred phthalazine compounds include compounds represented by the following general formula (5).

[0028]

[Chemical 5]

In the formula, the substituents R ^{4 to} R ⁹ are a halogen atom (eg, chlorine atom and fluorine atom), a cyano group,
Hydroxy group, alkyl group which may have a substituent (for example, methyl group, ethyl group, butyl group, octyl group, dodecyl group, etc.), alkenyl group (for example, allyl group, vinyl group, etc.), alkoxy group ( For example, methoxy group, ethoxy group, butoxy group, etc.), aromatic group (for example,
Phenyl group, naphthyl group, etc.) or heterocyclic group (eg, pyridyl group, furyl group, thiophenyl group, etc.). It may be a group that controls the diffusibility as a function of the substituent, a non-diffusible group, a diffusible group, an adsorptive group, an acidic group, or the like. The alkyl group, alkenyl group, and alkoxy group preferably have 1 to 60 carbon atoms, and particularly preferably have 1 to 40 carbon atoms. If the number of carbon atoms is large, good effects in fog control, color tone and storability cannot be obtained. These substituents may be the same as the substituents on the benzoxazine ring. Specific examples of preferable phthalazine compounds are shown below.

[0030]

[Chemical 6]

Use of the compound represented by the general formula (5)
The amount is preferably 1 x 10 per mol of silver.^-2-10 mol,
Particularly preferably 1 × 10^-2~ 1.5 mol. 10 mo
If the amount exceeds 1 mol of silver / silver, development fog will increase and color tone will increase.
Deterioration of 1 × 10 ^-2Less than the eyes of the present invention
Performance cannot be obtained. (Polyhalomethane compound) Polyhalomethane according to the present invention
The compound has few trihalomethane groups in one molecule.
A compound having at least one, substituted on an aliphatic group
Or substituted on an aromatic or heterocyclic group. Good luck
The aromatic ring group and heterocyclic group are further aromatic via a divalent linking group.
It may be linked to a group cyclic group or a heterocyclic group. As an aromatic ring group
Of these, a phenyl group and a naphthalene group are preferable.
Rogen atom on top (eg chlorine atom, bromine atom, fluorine
Atom, etc.), alkyl group (eg, methyl group, ethyl group,
Butyl group, octyl group, dodecyl group, octadecyl group
Etc.) and the like. As the heterocyclic group,
For example, pyridyl group, pyrimidyl group, quinolyl group, free
Group, thiophenyl group, imidazolyl group, triazolyl
Group, oxazolyl group, thiazolyl group, thiadiazolyl
Group, oxadiazolyl group, etc.
May have the same substituent as in the case of the aromatic ring group. Well
In addition, diffusion resistance is imparted to aromatic ring groups and heterocyclic groups.
Group for accelerating adsorption to silver halide
May be. The group adjacent to the trihalomethane group is sulfonyl.
A carbonyl group or a carbonyl group is preferred, but a direct aromatic group
It may be bonded to a ring group or a heterocyclic group, and the bonding method is limited.
Not determined. Aromatic and heterocyclic groups are
A reel type saturated ring group is particularly preferable. Trihalomethane group
The halogen atom of is preferably a bromine atom,
Elemental, Fluorine, Iodine, or a combination of these
Yes. Polyhalomethane compound having the above preferred structure
As a polyhalomethanation represented by the following general formula (6)
There is a mixture.

[0032]

[Chemical 7]

In the formula, X ¹ , X ² and X ³ represent a hydrogen atom, a halogen atom, an acyl group, an alkoxycarbonyl group, an aryloxycarbonyl group, a sulfonyl group or an aryl group, at least one of which is a halogen atom. . L
₃ -C (= O) -, - SO- or -SO ₂ - represents,
p represents 0 or 1. Z ² represents a ring group.

The ring group represented by Z ² is a saturated or unsaturated monocyclic or optionally condensed hydrocarbon ring group,
Examples of the heterocyclic group include a saturated or unsaturated monocyclic or optionally condensed hydrocarbon ring group, preferably a monocyclic or bicyclic saturated hydrocarbon ring group having 6 to 30 carbon atoms or an aromatic group. A cyclic group (eg, adamantyl group, cyclobutane group,
Cyclopropane group, cyclopentane group, cyclooctane group, cyclobutene group, cyclopentene group, cyclohexene group, phenyl group, naphthyl group, etc., and more preferably adamantyl group, cyclopentane group, cyclohexane group, cyclohexene group, cyclohexanone group. , Cyclopentene group, phenyl group, naphthyl group,
More preferably, it is a phenyl group. The heterocyclic group represented by Z ² includes a 3- to 10-membered saturated or unsaturated heterocyclic group containing at least one atom of N, O or S, and these may be monocyclic. However, it may form a condensed ring with another ring. The heterocyclic group is preferably a 5- or 6-membered saturated or unsaturated heterocyclic group which may have a condensed ring, and more preferably a 5- or 6-membered aromatic group which may have a condensed ring. It is a heterocyclic group. More preferably, it is a 5- or 6-membered saturated or unsaturated heterocyclic group which may have a condensed ring containing a nitrogen atom, particularly preferably 1 to 4 nitrogen atoms.
It is a 5- to 6-membered unsaturated heterocyclic group which may have a condensed ring containing atoms. Examples of the heterocycle in such a heterocyclic group include imidazole, pyrazole, pyridine, pyrimidine, pyrazine, pyridazine, triazole, triazine, indole, benzoxazine, purine, thiadiazole, oxadiazole, quinoline, phthalazine, naphthyridine, quinoxaline, quinazoline. ,
Cinnoline, pteridine, acridine, phenanthroline, phenazine, tetrazole, thiazole, oxazole, benzimidazole, benzoxazole, benzthiazole, indolenine, tetrazaindene and the like, preferably imidazole, pyridine, pyrimidine, pyrazine, pyridazine, triazole, Triazine, thiadiazole, oxadiazole, quinoline, phthalazine, naphthyridine, quinoxaline, quinazoline,
Tetrazole, thiazole, oxazole, benzimidazole, benzoxazole, benzthiazole, tetrazaindene, and the like, more preferably imidazole, pyridine, pyrimidine, pyrazine, pyridazine, triazole, triazine, thiadiazole, quinoline,
Examples thereof include phthalazine, naphthyridine, quinoxaline, quinazoline, cinnoline, tetrazole, thiazole, benzimidazole and benzthiazole, and particularly preferable examples are piperidine, piperazine, pyridine, thiadiazole, quinoline and benzthiazole. Preferred specific compounds are shown below.

[0035]

[Chemical 8]

[0036]

[Chemical 9]

[0037]

[Chemical 10]

The polyhalomethane compound according to the present invention can be added in an amount of usually 10 −6 mol to 10 ⁻² mol per silver halide. The position of addition is not limited to the photosensitive layer in which silver halide is present, and may be an adjacent layer or an undercoat layer. The addition method can be the same as that of the benzoxazine compound or its polymer or the phthalazine compound. Preferred specific examples are shown below.

Examples of the bisphenol compound preferably used in the present invention include compounds represented by the following general formula (7).

[0040]

[Chemical 11]

In the formula, R ^a is a hydrogen atom or has 1 carbon atom.
-10 alkyl groups (eg, methyl, ethyl, n
-C ₄ H ₉ group, 2,4,4-trimethylpentyl group), cyclohexyl group (for example, 1-methylcyclohexyl group, 4-methylcyclohexyl group, 3,5-dimethylcyclohexyl group, etc.) or cyclohexenyl group (for example, , 4-methylcyclohexenyl group, 4-methoxycyclohexenyl group, 3-chloro-4methylcyclohexenyl group, etc., and R ^b and R ^c each have 1 to 5 carbon atoms.
Alkyl group (for example, methyl group, ethyl group, t-butyl group, etc.), cyclohexyl group (for example, 1-methylcyclohexyl group, 4-methylcyclohexyl group, 3,5-
A dimethylcyclohexyl group or the like) or a cyclohexenyl group (eg, 4-methylcyclohexenyl group, 4-methoxycyclohexenyl group, 3-chloro-4-methylcyclohexenyl group, etc.), and R ^a , R ^b and R ^c At least one is a cyclohexyl group or a cyclohexenyl group.

Specific examples of the compound represented by the general formula (7) are shown below. However, the present invention is not limited to the following compounds.

[0043]

[Chemical 12]

[0044]

[Chemical 13]

Use of the compound represented by the general formula (7)
The amount is preferably 1 x 10 per mol of silver.^-2-10 mol,
Particularly preferably 1 × 10^-2~ 1.5 mol. 10 mo
If the amount exceeds 1 mol of silver / silver, development fog will increase and color tone will increase.
Deterioration of 1 × 10 ^-2Less than the eyes of the present invention
Performance cannot be obtained.

Next, the organic silver salt, the reducing agent, the photosensitive silver halide grains, the binder, the dye, the matting agent and the support used in the photothermographic image forming material of the present invention will be described in order.

(Organic Silver Salt) The organic silver salt contained in the photothermographic image-forming material of the present invention is a reducible silver source and contains an organic acid, a heteroorganic acid and an acid polymer containing a reducible silver ion source. The silver salt and the like are used. Also, the ligand is
Also useful are organic or inorganic silver salt complexes which generally have a total stability constant for silver ions of 4.0 to 10.0. Examples of silver salts are Research Disclosure No. 170.
29 and 29963, and include: silver salts of organic acids (eg, silver salts of gallic acid, oxalic acid, behenic acid, stearic acid, palmitic acid, lauric acid, etc.) and the like.

(Reducing Agent) Examples of preferable reducing agents contained in the photothermographic image-forming material of the present invention are described in US Pat.
70,448, 3,773,512, 3,59
3,863, etc., and Research Disclo
Sure Nos. 17029 and 29963, and include:

For example, bis (2-hydroxy-3-t-
Butyl-5-methylphenyl) methane, bis (6-hydroxy-m-tri) mesitol,
2,2-bis (4-hydroxy-3-methylphenyl)
It is propane or the like.

(Photosensitive silver halide grains) The photosensitive silver halide grains contained in the photosensitive layer of the photothermographic image forming material of the present invention are known in the field of photographic technology such as single jet or double jet method. By any method
For example, it can be prepared by any method such as an ammonia method, a neutral method and an acidic method, and then mixed with other components of the present invention and introduced into the composition used in the present invention.
In this case, in order to sufficiently bring the photosensitive silver halide grains into contact with the organic silver salt, for example, as a protective polymer when preparing the photosensitive silver halide grains, US Pat.
No. 6,564, No. 3,706,565, No. 3,7
Means using a polymer other than gelatin such as polyvinyl acetals described in 13,833, 3,748,143 and British Patent 1,362,970,
Means for enzymatically degrading gelatin in a light sensitive silver halide emulsion as described in British Patent 1,354,186 or light sensitive halogen as described in U.S. Pat. No. 4,076,539. By preparing the silver halide grains in the presence of a surfactant, it is possible to apply various means such as a method for omitting the use of the protective polymer.

The photosensitive silver halide grains preferably have a small grain size in order to suppress white turbidity after image formation and to obtain good image quality. The average particle size is usually 0.1 μm or less, preferably 0.01 to 0.1 μm.
m, 0.02 to 0.08 μm is particularly preferable. The shape of the photosensitive silver halide grain is not particularly limited, and is a cubic or octahedral so-called normal crystal or non-normal crystal spherical, rod-shaped,
There are tabular grains. The silver halide composition is also not particularly limited and may be any of silver chloride, silver chlorobromide, silver chloroiodobromide, silver bromide, silver iodobromide and silver iodide.

The amount of the photosensitive silver halide grains is usually 50% by mass or less, preferably 25 to 0.1% by mass, more preferably 15 to 10% by mass based on the total amount of the photosensitive silver halide grains and the organic silver salt described below. It is between 0.1 mass%. Reaction temperature, reaction time in the step of converting a part of the organic silver salt into silver halide using the above photosensitive silver halide grain forming component,
Although various conditions such as reaction pressure can be appropriately set according to the purpose of production, the reaction temperature is usually -23 to 74 ° C, the reaction time is 0.1 second to 72 hours, and the reaction pressure is large. It is preferably set to atmospheric pressure.

The photosensitive silver halide grains prepared by the above-mentioned various methods are chemically sensitized with, for example, a sulfur-containing compound, a gold compound, a platinum compound, a palladium compound, a silver compound, a tin compound, a chromium compound or a combination thereof. can do. The method and procedure of this chemical sensitization are described in, for example, U.S. Pat. No. 4,036,650, British Patent 1,518,850, and Japanese Patent Laid-Open No. 51-2243.
0, 51-78319, 51-81124 and the like. When a part of the organic silver salt is converted into photosensitive silver halide grains by the silver halide forming component,
As described in US Pat. No. 3,980,482, low molecular weight amide compounds may be co-present to achieve sensitization.

Further, these photosensitive silver halide grains contain metals belonging to groups 6 to 10 of the periodic table of the elements, such as Rh, Ru, Re and I, for adjusting illumination irregularity and gradation.
Ions such as r, Os, and Fe, or a complex or complex ion thereof can be contained. Especially from Group 6 of the Periodic Table of the Elements
It is preferable to contain an ion of a metal belonging to Group 0 or a complex ion. The above metals include W, Fe, Co,
Ni, Cu, Ru, Rh, Pd, Re, Os, Ir, P
t and Au are preferable, and among them, when they are used for a photosensitive material for printing plate making, they are preferably selected from Rh, Re, Ru, Ir and Os. These metals can be introduced into the silver halide in the form of a complex.

As the content of metal ions or complex ions
Is usually 1 × 10 1 per mol of silver halide.^-9~ 1x
10^-2Moles are suitable, preferably 1 x 10^-8~ 1x
10 ^-FourIt is a mole. Ions or complex ions of these metals
The compound that provides the silver halide is added when the silver halide grains are formed.
And is preferably incorporated into the silver halide grain.
Preparation of silver halide grains, i.e. nucleation, growth,
It may be added at any stage before and after ripening and chemical sensitization.
Is added especially at the stage of nucleation, growth and physical ripening.
It is preferable to add at the stage of nucleation and growth.
Most preferably, it is added at the stage of nucleation. Addition
In this case, it may be added dividedly over several times.
It can be contained uniformly in the silver halide grains,
JP-A-63-29603, JP-A-2-306236
No. 3, No. 3-167545, No. 4-76534, No. 6
No. 110146, No. 5-273683, etc.
It is also possible to have a distribution within the particles as shown in
Wear. Preferably it can have a distribution inside the particles
It

These metal compounds can be added after being dissolved in water or a suitable organic solvent (eg alcohols, ethers, glycols, ketones, esters, amides). Or an aqueous solution of a metal compound and NaCl or KCl dissolved in a water-soluble silver salt solution or a water-soluble halide solution during the formation of halogenated grains, or a silver salt solution and a halide Third when the solutions are mixed simultaneously
A method of preparing silver halide grains by a method of simultaneous mixing of three liquids, a method of adding a necessary amount of an aqueous solution of a metal compound into a reaction vessel during the formation of silver halide grains,
Alternatively, there is a method of adding and dissolving another silver halide grain which is previously doped with a metal ion or a complex ion when preparing the silver halide grain. In particular, a method of adding an aqueous solution of a powder of a metal compound or an aqueous solution in which a metal compound and NaCl or KCl are dissolved together to a water-soluble halide solution is preferable. When added to the surface of silver halide grains, a necessary amount of an aqueous solution of a metal compound may be added to a reaction vessel immediately after the formation of silver halide grains, during or during physical ripening, or during chemical ripening.

(Spectral Sensitizing Dye) The spectral sensitizing dye used in the present invention may be, for example, as disclosed in JP-A-63-15.
9841, 60-140335, 63-231.
No. 437, No. 63-259651, No. 63-3042.
42, 63-15245, U.S. Pat. No. 4,63.
No. 9,414, No. 4,740,455, No. 4,7
41,966, 4,751,175, 4,
The sensitizing dyes described in 835,096 and the like can be used. Useful sensitizing dyes used in the present invention are eg Res
searchDisclosure Item 17643IV-A (Dec. 1978, p.23), Item 1831X (1)
August 978 p. 437) or cited therein. In particular, a sensitizing dye having a spectral sensitivity suitable for the spectral characteristics of various scanner light sources can be advantageously selected. For example, JP-A-9-34078 and 9-
The compounds described in Nos. 54409 and 9-80679 are preferably used.

(Binder) As the polymer binder preferable as a binder used in the light-sensitive layer or the non-light-sensitive layer of the photothermographic image-forming material of the present invention, a silver halide, an organic silver salt, or a reducing agent reacts. As a preferable material, a material preferable for a reaction in which a heat-erasable dye is usually decolored by heat of 80 to 200 ° C.,
Alternatively, a material is selected so that the base-generating precursor rapidly generates a base by heat. Examples of the polymer binder include alcohols such as methanol and ethanol, ketones such as methyl ethyl ketone and acetone, polymers used by being dissolved in a polar solvent containing dimethyl sulfoxide and dimethylformamide, and water-dispersed polymers. Any polymer binder may be used in the photothermographic image-forming material of the present invention. Further, the above-mentioned polymer preferably has a glass transition point of −20 to 80 ° C.,
Those of 5 to 60 ° C. are particularly preferable. This is because when the glass transition point is high, the temperature for heat development becomes high, and when the glass transition point is low, fog is likely to occur, resulting in a decrease in sensitivity and a soft tone.

Examples of the polymer to be used after dissolved in the polar solvent or the like are cellulose derivatives such as hydroxyethyl cellulose, carboxymethyl cellulose, methyl cellulose and ethyl cellulose, starch and its derivatives, polyvinyl alcohol, modified polyvinyl alcohol, polyvinyl butyral, polyacrylic acid. Sodium, polyethylene oxide, acrylic acid amide-acrylic acid ester copolymer, styrene-maleic anhydride copolymer, polyacrylamide, sodium alginate,
Gelatin, casein, polystyrene, polyvinyl acetate,
Examples thereof include polyurethane, polyacrylic acid, polyacrylic acid ester, styrene-butadiene copolymer, acrylonitrile-butadiene copolymer, vinyl chloride-vinyl acetate copolymer, styrene-butadiene-acrylic copolymer. After further drying, after forming a film, the coating film preferably has a low equilibrium water content, and particularly low water content includes, for example, cellulose acetate, cellulose acetate butyrate, poly (methylmethacrylic acid), and the like. Acrylic esters), poly (acrylic acid), poly (methacrylic acid), poly (vinyl chloride), copoly (styrene-maleic anhydride), copoly (styrene-acrylonitrile), copoly (styrene-butadiene), poly (vinyl) Acetal) (for example, poly (vinyl formal), poly (vinyl butyral), etc.), poly (ester), poly (urethane), phenoxy resin, poly (vinylidene chloride), poly (epoxide),
Poly (carbonate) s, poly (vinyl acetate),
Cellulose esters, poly (amides) and the like can be mentioned.

(Crosslinking Agent) The binder can maintain the adhesion to the lower layer and the upper layer and form a film with scratch resistance by forming the film alone. It is possible to improve film adhesion and film strength. The crosslinking agent can be used by adding it to the undercoat layer, adding it to the AH layer, the photosensitive layer, the protective layer, the backing layer, the backing layer protective layer and the like. From the viewpoint of the stability of the coating liquid, it is preferable to add it using a static mixer immediately before coating, but it may be added at the time of preparing the coating liquid.
As a preferable crosslinking agent, a crosslinking agent having an isocyanate group, a vinylsulfonyl group or an epoxy group is preferable. As a particularly preferable crosslinking agent, a polyfunctional crosslinking agent having at least two isocyanate groups can be mentioned. Specific compound examples of preferable crosslinking agents are shown below.

[0061] (H-1) Hexamethylene diisocyanate (H-2) hexamethylene diisocyanate trimer (H-3) Tolylene diisocyanate (H-4) Phenylene diisocyanate (H-5) Xylylene diisocyanate

[0062]

[Chemical 14]

(Dye Used in AI Layer or BC Layer as Necessary) The photothermographic image-forming material of the present invention may optionally contain an anti-irradiation layer for preventing irradiation or halation of the photothermographic image-forming material ( AI
Layer) or antihalation layer (ie backing layer (BC
Layer)) is provided, and the dye used in the AI layer or the BC layer may be any dye that absorbs image exposure light,
Preferably, the thermal decolorizable dye described in the above-mentioned US Pat. No. 5,384,237 is used. When the dye used is not heat decolorizable, the amount used is limited to a range that does not cause image damage to the photothermographic image forming material,
If it is a heat-decolorable dye, a necessary and sufficient amount of dye can be added.

(Matting Agent) The matting agent may be either an organic substance or an inorganic substance. Examples of the inorganic matting agent include silica described in Swiss Patent No. 330,158 and Swiss Patent No. 330,158. Polystyrene or polymethacrylate described in US Pat.
The polyacrylonitrile described in 079,257 and the polycarbonate described in US Pat. No. 3,022,169 can be used.

The shape of the matting agent may be either a fixed shape or an amorphous shape, but it is preferably a fixed shape, and a spherical shape is preferably used. The size of the matting agent is represented by the diameter when the volume of the matting agent is converted into a spherical shape. In the present invention, the particle size of the matting agent refers to the spherically converted diameter. The matting agent used in the present invention has an average particle size of 0.5.
It is preferably from 10 to 10 μm, more preferably 1.
It is 0 to 8.0 μm. The degree of monodispersion of the particles is preferably 50% or less, more preferably 40% or less, and particularly preferably 20% or less. Here, the monodispersity of the particles is represented by a number obtained by dividing the standard deviation of the particle diameter by the average value of the particle diameters and multiplying by 100. The matting agent may be added by dispersing it in the coating solution in advance and applying it, or by spraying the matting agent after applying the coating solution and before drying is completed.

(Support) As the support, paper, synthetic paper,
A support such as a non-woven fabric, a metal foil or a plastic film can be used, and a composite sheet in which these are combined may be optionally used.

(Image exposure) As an exposure method, Japanese Patent Laid-Open No.
No. 304869, No. 9-311403 and JP-A-2
Laser exposure can be carried out by the method described in No. 000-10230.

(Heat Developing Device) The device for developing the photothermographic image forming material is disclosed in JP-A-11-65067 and 11-7.
The devices described in 2897 and 11-84619 can be used.

[0069]

The present invention will be specifically described below with reference to examples, but the embodiments of the present invention are not limited to these.

Example 1 <Preparation of Subbed Support> A polyethylene terephthalate support having a thickness of 175 μm was subjected to corona discharge treatment at 8 W / m ² · min for both surfaces, and one surface thereof was provided with the subbing coating solution a- 1 is applied to a dry film thickness of 0.8 μm and dried to provide an undercoat layer A-1, and the undercoating coating solution b-
1 was coated and dried to a dry film thickness of 0.8 μm to form an undercoat layer B-1.

[0071]   << Subbing coating solution a-1 >>   Butyl acrylate (30 mass%), t-butyl acrylate     (20% by mass), styrene (25% by mass), 2-     Hydroxyethyl acrylate (25% by mass) copolymer latex liquid     (Solid content 30%) 270 g   Hexamethylene-1,6-bis (ethylene urea) 0.8 g   Make up to 1 liter with water.

[0072]   <Subbing coating solution b-1>   Butyl acrylate (40% by mass), styrene (20% by mass),     Copolymer latex liquid of glycidyl acrylate (40% by mass)     (Solid content 30%) 270 g   Hexamethylene-1,6-bis (ethylene urea) 0.8 g   Make up to 1 liter with water.

Subsequently, the undercoat layer A-1 and the undercoat layer B-1
8 W / m ² · min of corona discharge is applied to the upper surface of the undercoat layer, and the undercoating upper layer coating solution a-2 is applied and dried on the undercoating layer A-1 to a dry film thickness of 0.1 μm. To form an undercoating upper layer A-2, and the following undercoating upper layer coating liquid b-2 is provided on the undercoating layer B-1.
Was coated and dried to a dry film thickness of 0.8 μm to provide an undercoating upper layer B-2 having an antistatic function.

<< Undercoating Upper Layer Coating Liquid a-2 >> Gelatin 0.4 g / m ² Mass Silica Particles (Average Particle Size 3 μm) 0.1 g Finish with Water to 1 L << Undercoating Upper Layer Coating Liquid b-2 >> Styrene-butadiene copolymer latex liquid (solid content 20%) 80 g Polyethylene glycol (mass average molecular weight 600) 6 g Water is made up to 1 liter.

<Preparation of silver halide grain emulsion A> Water 90
7.5 g of inert gelatin and 10 mg of potassium bromide were dissolved in 0 ml to adjust the temperature to 28 ° C. and pH to 3.0, and then 370 ml of an aqueous solution containing 74 g of silver nitrate (98 /
An aqueous solution containing potassium bromide and potassium iodide in the molar ratio of 2) was added by the controlled double jet method over 10 minutes while keeping the pAg at 7.7. Hexachloroiridium sodium salt was added to 10 ^{-6 in} synchronism with the addition of silver nitrate.
Mol / silver 1 mol was added. Then 4-hydroxy-6-
Methyl-1,3,3a, 7-tetrazaindene 0.3 g
Was added and the pH was adjusted to 5 with NaOH, the average particle size was 0.036 μm, the variation coefficient of the projected diameter area was 8%, [10
0] Cubic silver iodobromide grains having an area ratio of 87% were obtained. This emulsion was coagulated and sedimented using a gelatin coagulant, desalted, and added with 0.1 g of phenoxyethanol to give a pH of 5.9 and pA.
It was adjusted to g 7.5 to obtain a silver halide grain emulsion A.

<Preparation of Organic Silver Salt> 111.4 g of behenic acid, 83.8 g of arachidic acid and 54.9 g of stearic acid were dissolved in 4720 ml of pure water at 80 ° C. Next, while stirring at high speed, a 1.5 mol / L sodium hydroxide aqueous solution 5
After adding 40.2 ml and adding 6.9 ml of concentrated nitric acid,
It cooled at 5 degreeC and the organic-acid sodium solution was obtained. While maintaining the temperature of the above-mentioned sodium salt of an organic acid at 55 ° C., 420 ml of pure water was added to the silver halide grain emulsion A (containing 0.038 mol of silver) and stirred for 5 minutes. Then 1 mol /
760.6 ml of silver nitrate solution of L was added over 2 minutes,
The mixture was stirred for 20 minutes, and the water-soluble salts were removed by filtration. Thereafter, washing with deionized water and filtration were repeated until the electric conductivity of the filtrate became 2 μS / cm, and the filtered substance was dried.

<Coating of Photosensitive Layer and BC Layer> The following layers were sequentially formed on the support provided with the undercoat layer to prepare a photothermographic image forming material sample. In addition, each is dried at 45 ℃, 1
I went in minutes.

<< Coating on BC Layer >> On the back surface side, a coating solution prepared by further adding water to an aqueous solution or water dispersion of the following heat-decolorable dye and other composition is prepared so as to have the following coating amount. The coating was dried to form a BC layer.

<< BC Layer Coating >> Inert gelatin 1.8 g / m ² Thermally decolorizable dye C1 1.2 × 10 ⁻⁵ mol / m ² Surfactant: N-propyloctylsulfonamidoacetic acid 0.02 g / m ² Dihexyl sulfosuccinic acid sodium salt 0.02 g / m ² Hardener: 1,2-bis (vinylsulfonamide) ethane 0.02 g / m ² << Coating of BC layer protective layer >> Inert gelatin 1.1 g / m ² hard Membrane agent: 1,2-bis (vinylsulfonamide) ethane 0.01 g / m ² Surfactant: N-propyl perfluorooctyl sulfonamide acetic acid 0.02 g / m ² Matting agent (PMMA: average particle size 5 μm) 0 .12 g / m ² << Coating on photosensitive layer side >><< Coating of AI layer >> For the formation of the AI layer, a coating solution was prepared by dissolving the following composition in a methyl ethyl ketone solvent. This coating solution was kept at around 35 ° C. and coated and dried so as to have the following coating amounts.

Binder: PBV-1 0.4 g / m ² Thermally decolorizable dye C1 6 × 10 ⁻⁵ mol / m ² << Coating of photosensitive layer >> The following composition was dissolved in a methyl ethyl ketone solvent to form a photosensitive layer. The prepared coating liquid was prepared. This coating solution was kept at around 35 ° C. and coated and dried so as to have the following coating amounts.

Organic silver salt (including silver halide) Silver amount 1.36 g / m ² Binder: PVB-1 2.6 g / m ² Benzoxazine compound of the present invention or polymer thereof (see Table 1) 3. 2 × 10 ⁻⁴ equivalent / m ² spectral sensitizing dye A1 2 × 10 ⁻⁵ mol / m ² antifoggant-1: pyridinium hydrobromide perbromide 0.3 mg / m ² antifoggant-2: isothiazolone 1.2 mg / M ² Reducing agent: 2,6-diisopropyl-4-methylphenol 3.3 mmol / m ² << Photosensitive layer protective layer >> A coating solution prepared by adding the following composition so that the coating amount is as follows. The surface protective layer was formed by coating and drying on the photosensitive layer. The AI layer, the photosensitive layer and the protective layer were coated by a common slide simultaneous multilayer coating.

Cellulose acetate butyrate 1.2 g / m ² 4-methylphthalic acid 0.7 g / m ² tetrachlorophthalic acid 0.2 g / m ² tetrachlorophthalic anhydride 0.5 g / m ² silica matting agent (average Particle size 5 μm) 0.5 g / m ²

[0083]

[Chemical 15]

<Evaluation of Photographic Performance> The sample prepared above was divided into two, and one of them was subjected to 3 in an atmosphere of 25 ° C. and 60% RH.
Stored for a day (hereinafter, this sample is also referred to as a normal humidity sample)
After that, it was exposed with a sensitometer for semiconductor laser exposure of 810 nm, and after exposure, heat development treatment was performed at 120 ° C. for 8 seconds to form an image. The other one was stored in a high humidity atmosphere of 35 ° C. and 78% RH for 3 days (hereinafter, this sample is also referred to as a high humidity sample), and then similarly exposed and heat-developed to form an image. The laser exposure and heat development treatment of the above normal humidity sample were performed in a room where the humidity was adjusted to 25 ° C. ± 1 ° C. and relative humidity 54% ± 1%. Immediate Performance Sensitivity and Fog Sensitivity and fog were measured with a Macbeth densitometer for the sample on which an atmospheric humidity sample was exposed and heat-developed as described above to form an image.

The sensitivity was obtained as the reciprocal of the ratio of the exposure dose which gives a density 0.3 higher than the fog density, and the value of Sample 101 was 100.
It shows with the relative value. Exposing raw stock storability difference in fog (F ₂ -F ₁₎ and the difference in sensitivity (S ₁ -S ₂₎ as described above normal humidity sample, high humidity sample, respectively,
For each sample to form an image subjected to thermal development, the sensitivity and fog were measured by a Macbeth densitometer, of normal humidity sample Fog (F _1), the sensitivity (S ₁₎ and high humidity sample fog (F ₂ ), the sensitivity (S _2), and obtains a difference in fog (F ₂ -F ₁₎ and the difference in sensitivity (S ₁ -S _2). The smaller the increase in fog and the decrease in sensitivity, the better the raw storage stability.

The results are shown in Table 1.

[0087]

[Table 1]

As is clear from Table 1, the sample containing the benzoxazine compound of the present invention or the polymer thereof (the constitutions of the inventions 1 and 2 of the present invention) is higher than other samples (comparative). Thus, it can be seen that the photographic performance (sensitivity, fog) and raw storability during heat development are excellent.

Example 2 A sample was prepared and its performance was evaluated in the same manner as in Example 1, except that the benzoxazine compound of the present invention or a polymer thereof was added to the AI layer and the photosensitive layer in the following amounts. Then, the fog, sensitivity and raw preservation property were evaluated. AI layer: 1.2 × 10 ⁻⁵ mol / m ² Photosensitive layer: 2.1 × 10 ⁻⁴ mol / m ^{2 The} results are shown in Table 2.

[0090]

[Table 2]

As is clear from Table 2, when the benzoxazine compound of the present invention or a polymer thereof and a phthalazine compound are used, fog, sensitivity and raw storage stability are more excellent.

Example 3 A sample was prepared in the same manner as in Example 1, except that a polyhalomethane compound (3.6 × 10 ^-4 mol / silver 1 mol) and a phthalazine compound (2.6 × 10 ^-4 mol) were used. / Silver 1 mol), a bisphenol compound (3.8 × 10 ^-4 mol / silver 1 mol), and a cross-linking agent (2.6 × 10 ^-4 mol / m ² ) were added to the photosensitive layer for photographic performance and raw storage. The sex was evaluated in the same manner as in Example 1. Image storability Further, in order to evaluate the image storability, a test for printout silver fogging and a maximum density decrease (-ΔDmax value) was conducted as follows.

Printout Silver Fog The obtained developed sample was illuminated with a fluorescent lamp of 1000 lux. A diffusion sheet was interposed between the fluorescent lamp and the test sample so that the light irradiation was uniform. The printout silver fog was measured by changing the irradiation time. Table 3 shows the values of the printout silver fog after irradiation for 3 hours.

Decrease in maximum density (-ΔDmax) Simultaneously with measurement of printout silver fog, decrease in maximum density (-ΔDmax)
As the evaluation of Dmax, the maximum density (Dmax2) was measured, and the maximum density (Dmax) when the fluorescent lamp was not irradiated was measured.
max1) decrease in maximum density (-ΔDmax)
Was calculated (-ΔDmax =-(Dmax2-Dmax
1)). The smaller the value, the better the decrease in maximum density.

Residual color For the residual color, the heat-developed sample was visually evaluated on a 5-grade scale. Rank 5 is the best level with no residual color, Rank 1
Is the worst level, rank 3 is a level that has no practical problem, and rank 2 is a level that is practically problematic.

The results are shown in Table 3.

[0097]

[Table 3]

As is clear from Table 3, when the benzoxazine compound of the present invention or its polymer, and the polyhalomethane compound, the bisphenol compound and the cross-linking agent are used, image storability (printed-out silver fog, decrease in maximum density) and It can be seen that raw storability (difference in fog, difference in sensitivity) and immediate performance (fogging, sensitivity) are further improved. It can also be seen that there are less residual colors.

[0099]

INDUSTRIAL APPLICABILITY The present invention can provide a photothermographic image forming material excellent in high sensitivity and low fog in photographic performance. Further, it is possible to provide a photothermographic image forming material in which fogging due to printed silver after development is suppressed. Further, it is possible to provide a photothermographic image-forming material which is excellent in raw storability before development and image storability after development, has little residual color after development, and has stable color tone.

Claims (6)

[Claims] 1. A photothermographic image-forming material having a photosensitive layer containing a photosensitive silver halide grain, an organic silver salt, a reducing agent and a binder on a support, containing a benzoxazine compound or a polymer thereof. A photothermographic image forming material characterized by: 2. A benzoxazine compound represented by the following general formula (1) or (2), or a benzoxazine represented by the following general formula (3) or (4) The photothermographic image forming material according to claim 1, which is a polymer of a compound. [Chemical 1] (In the general formula (1) to the general formula (4), R ¹ , R ² and R
³ represents a hydrogen atom, a halogen atom, an alkyl group, a fluorinated alkyl group, an alkoxy group, a hydroxy group or a carboxyalkyl group, n represents an integer of 0 to 1000, and L
₁ and L ₂ represent a divalent linking group. However, the case where R ¹ is a hydrogen atom is excluded. ) 3. The photothermographic image forming material according to claim 1, wherein the photosensitive layer or a layer adjacent to the photosensitive layer contains a phthalazine compound. 4. The photothermographic image forming material according to claim 1, wherein the photosensitive layer or a layer adjacent to the photosensitive layer contains a polyhalomethane compound. 5. The photothermographic image forming material according to claim 1, wherein the photosensitive layer or a layer adjacent to the photosensitive layer contains a bisphenol compound. 6. The cross-linking agent for cross-linking the binder of the photosensitive layer or a layer adjacent to the photosensitive layer is at least one selected from an isocyanate compound, a vinyl sulfone compound and an epoxy compound. The photothermographic image forming material according to any one of 1 to 5.