JP2006162650A - Silver salt photothermographic dry imaging material and method for manufacturing the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a silver salt photothermographic dry imaging material which has low fog and obtains satisfactory film adherence strength from a time immediately after development. <P>SOLUTION: In the silver salt photothermographic dry imaging material having on a support a photosensitive layer containing: non-photosensitive silver salt of aliphatic carboxylic acid particles; photosensitive silver halide grains; a silver ion reducing agent; and a binder, a surface pH of the support on the photosensitive layer side is 3.0 to <8.0. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a silver salt photothermographic dry imaging material and a method for producing the same.

  In recent years, in the fields of medical treatment and printing plate making, reduction of waste liquid accompanying wet processing of image forming materials has been strongly desired from the viewpoint of environmental protection and space saving.

  Therefore, technology related to photothermographic dry imaging materials for photographic technology that enables efficient exposure and can form clear black images with high resolution, such as laser imagers and laser imagesetters, is required. It has been said that.

  As a technique related to the photothermographic material, for example, a silver salt photothermographic dry imaging material containing an organic silver salt, a photosensitive silver halide and a reducing agent on a support is known (see, for example, Patent Documents 1 and 2). .) Since this silver salt photothermographic dry imaging material does not use any solution processing chemicals, it has an advantage that it can provide a user with a simpler system that does not impair the environment.

  These silver salt photothermographic dry imaging materials use photosensitive silver halide particles placed in the photosensitive layer as a photosensor, use organic silver salt as a source of silver ions, and are usually 80 to 80% depending on a built-in reducing agent. It is characterized in that an image is formed by heat development at 140 ° C. and fixing is not performed.

  However, in the silver salt photothermographic dry imaging material, the photosensitive layer contains organic silver salt and photosensitive silver halide grains. Therefore, unlike the wet development type film, the photosensitive layer is relatively thick and has a film. Strength tends to deteriorate.

A technique for recovering the strength with a film is known. However, the strength with a film immediately after development processing is insufficient, or the strength with film is insufficient with a film immediately after coating. Moreover, when the film attachment is improved, the fog rises and further improvement is desired.
JP 2001-183971 A (pages 2 to 6) JP 2003-57788 A (pages 3 to 8)

  The present invention has been made in view of the above-described background circumstances, and an object of the present invention is to provide a silver salt photothermographic dry imaging material that has low fog and can obtain sufficient film-attached strength immediately after development processing. .

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

(Claim 1)
In a silver salt photothermographic dry imaging material having a photosensitive layer containing non-photosensitive aliphatic carboxylic acid silver salt particles, photosensitive silver halide particles, a silver ion reducing agent and a binder on a support, A silver salt photothermographic dry imaging material having a film surface pH of 3.0 or more and less than 8.0 on the photosensitive layer side.

(Claim 2)
A coating solution for photosensitive layer containing non-photosensitive aliphatic carboxylic acid silver salt particles, photosensitive silver halide particles, a silver ion reducing agent and a binder has a film surface pH within the range of 3.0 or more and less than 8.0. A method for producing a silver salt photothermographic dry imaging material, characterized in that the silver salt photothermographic dry imaging material is produced by coating the substrate on a support and drying it.

  According to the present invention, it is possible to provide a silver salt photothermographic dry imaging material having low fog and obtaining a sufficient strength with a film immediately after development processing.

  The present invention will be described in more detail.

[Support]
Examples of the support material used in the silver salt photothermographic dry imaging material (hereinafter also simply referred to as photosensitive material) of the present invention include various polymer materials, glass, wool cloth, cotton cloth, paper, metal (for example, aluminum), and the like. In view of handling as an information recording material, a material that can be processed into a flexible sheet or roll is preferable. Therefore, as a support in the silver salt photothermographic dry imaging material of the present invention, a plastic film (for example, cellulose acetate film, polyester film, polyethylene terephthalate film, polyethylene naphthalate film, polyamide film, polyimide film, cellulose triacetate film, polycarbonate film, etc. In the present invention, a biaxially stretched polyethylene terephthalate film is particularly preferable. The thickness of the support is about 50 to 300 μm, preferably 70 to 180 μm.

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

  The silver salt photothermographic dry imaging material of the present invention has at least one photosensitive layer on a support. Although only the photosensitive layer may be formed on the support, it is preferable to form at least one non-photosensitive layer on the photosensitive layer. For example, a protective layer is provided on the photosensitive layer for the purpose of protecting the photosensitive layer, and on the opposite side of the support to prevent sticking between the photosensitive materials or in the photosensitive material roll. A layer is preferably provided. Binders used in these protective layers and backcoat layers have a glass transition point higher than that of the heat-developable layer, and polymers such as scratches and deformations, such as cellulose acetate and cellulose acetate butyrate, are the above-mentioned binders. It is chosen from among them. For gradation adjustment and the like, in the present invention, the photosensitive layer is preferably composed of two or more layers. For example, two or more photosensitive layers may be provided on one side of the support, or the support. One or more layers may be installed on both sides.

  In the silver salt photothermographic dry imaging material of the present invention, a filter layer is formed on the same side as or opposite to the photosensitive layer in order to control the amount of light transmitted through the photosensitive layer or the wavelength distribution. It is preferable to contain a dye or pigment in the layer.

  As the dye used, known compounds that absorb light in various wavelength regions can be used depending on the color sensitivity of the photosensitive material.

  For example, when the silver salt photothermographic dry imaging material of the present invention is used as an image recording material by infrared light, a squarylium dye having a thiopyrylium nucleus as disclosed in JP-A-2001-83655 (in this specification, Thiopyrylium squarylium dyes) and squarylium dyes with pyrylium nuclei (referred to herein as pyrylium squarylium dyes), thiopyrylium croconium dyes similar to squarylium dyes, or pyrylium croconium dyes It is preferable.

  The compound having a squarylium nucleus is a compound having 1-cyclobutene-2-hydroxy-4-one in the molecular structure, and the compound having a croconium nucleus is 1-cyclopentene-2-hydroxy- in the molecular structure. It is a compound having 4,5-dione. Here, the hydroxyl group may be dissociated. Hereinafter, in the present specification, these pigments are collectively referred to as squarylium dyes for convenience.

  As the dye, a compound described in JP-A-8-201959 is also preferable.

[Measurement method of membrane surface pH of support]
Specific examples of instruments that can be measured with a commercially available pH meter having a planar electrode include Compact pH Meters B211 / B212 manufactured by HORIBA, Ltd. The measurement was performed by cutting the undercoated support into 1 cm ² , adding 0.05 ml of pure water dropwise onto the film surface on the side where the photosensitive layer was applied, and uniformly spreading the entire surface, followed by 25 ° C. and 70%. Measurements were taken after 5 minutes in an RH environment. In the case of a coated silver salt photothermographic dry imaging material, the coating layer above the photosensitive layer is dissolved and removed with a solvent such as methyl ethyl ketone, and the film surface of the remaining undercoat layer is measured by the above method. . If the protective layer is hardly soluble in a solvent such as methyl ethyl ketone, a cello tape (registered trademark) with strong adhesive strength is applied and peeled off, and then treated with methyl ethyl ketone.

[Means for controlling the membrane surface pH of the support]
As a means for controlling the film surface pH of the support, an undercoat layer is usually provided on the support in order to improve the adhesion to the photosensitive layer, but the film surface of this undercoat layer that adheres to the photosensitive layer By controlling the pH, the membrane surface pH of the support can be controlled. Specifically, the film surface pH can be lowered by lowering the pH of the undercoat layer coating solution, and the film surface pH can be raised by increasing the pH of the undercoat layer coating solution. However, if a volatile pH control agent, specifically ammonia or the like, is used, the above-described effects cannot be sufficiently exhibited.

  As compounds preferably used for controlling the pH, alkali metal hydroxides such as NaOH and KOH, inorganic acids such as hydrochloric acid, sulfuric acid and nitric acid, and organic acids such as acetic acid are used. Moreover, it is also possible to reduce the fluctuation | variation of pH by adding a buffer agent.

  The film surface pH of the present invention is in the range of 3.0 to 8.0, preferably 4.0 to 6.0. When the pH is lowered, the film attachment is deteriorated, and when the pH is too high, there is a problem that the fog of the emulsion increases.

〔binder〕
The binder suitable for the undercoat layer of the silver salt photothermographic dry imaging material of the present invention is preferably used as an aqueous dispersion (latex) as a hydrophobic resin. Examples of the hydrophobic resin that can be preferably used in the present invention include styrene-butadiene copolymer, polyacrylic acid, polyacrylate ester and derivatives thereof, polyvinyl acetate, vinyl acetate-acrylate copolymer, polyolefin, olefin-acetic acid. Emulsions such as vinyl copolymers can also be used. In addition, organic semiconductors such as carbonate-based, polyester-based, urethane-based, epoxy-based resin, polyvinyl chloride, polyvinylidene chloride, and polypyrrole can also be used. These hydrophobic resins can be used in admixture of two or more, but acrylic copolymers are preferred.

  The acrylic copolymer preferably contains, for example, at least 20 mol% or more of alkyl acrylate or alkyl methacrylate. The copolymer component is preferably selected from styrene, styrene derivatives, olefin derivatives, halogenated ethylene derivatives, vinyl ester derivatives, acrylonitrile and the like.

  Examples of hydrophilic resins used in the undercoat layer include proteins such as gelatin, derivative gelatin, colloidal albumin, and casein: cellulose compounds such as carboxymethyl cellulose, hydroxyethyl cellulose, diacetyl cellulose, and triacetyl cellulose; agar, sodium alginate, and starch derivatives Many other synthetic resins such as synthetic hydrophilic colloids such as polyvinyl alcohol, poly-N-vinyl pyrrolidone, polyacrylic acid copolymer, polyacrylamide or derivatives thereof, and partial hydrolysates are used. However, polyvinyl alcohol is particularly preferably used as the hydrophilic resin.

  Examples of the polymer containing a vinyl alcohol unit include polyvinyl alcohol derivatives such as ethylene-copolymerized polyvinyl alcohol and modified polyvinyl alcohol obtained by partial butyralization and dissolved in water. As polyvinyl alcohol, a polymerization degree of 100 or more is preferable.

  Preferred binders for the photosensitive layer of the silver salt photothermographic dry imaging material of the present invention are polyvinyl acetals, and a particularly preferred binder is polyvinyl butyral. Details will be described later. In addition, for non-photosensitive layers such as overcoat layers and undercoat layers, especially protective layers and backcoat layers, cellulose esters which are polymers having a higher softening temperature, particularly polymers such as triacetyl cellulose and cellulose acetate butyrate. Is preferred. In addition, as needed, said binder can be used in combination of 2 or more type.

Such a binder is used in an effective range to function as a binder. The effective range can be easily determined by one skilled in the art. For example, as an index for holding at least an aliphatic carboxylic acid silver salt in the photosensitive layer, the ratio of the binder to the aliphatic carboxylic acid silver salt is 15: 1 to 1: 2, particularly 8: 1 to 1: 1. The range of is preferable. That is, it is preferable amount of the binder in the photosensitive layer is 1.5~6g / m ^2. More preferably, it is 1.7-5 g / m < ² >. If it is less than 1.5 g / m ² , the density of the unexposed area is significantly increased and may not be used.

  In the present invention, the heat transition temperature after development at a temperature of 100 ° C. or higher is preferably 46 ° C. or higher and 200 ° C. or lower, more preferably 70 ° C. or higher and 105 ° C. or lower. The heat transition temperature referred to in the present invention is a value indicated by the VICAT softening point or ring-and-ball method, and is a differential scanning calorimeter (DSC), for example, EXSTAR 6000 (manufactured by Seiko Electronics), DSC220C (manufactured by Seiko Electronics Industry) DSC-7 (manufactured by Perkin Elmer) or the like is used to indicate the endothermic peak when the thermally developed photosensitive layer is isolated and measured. Generally, a polymer compound has a glass transition point Tg, but in a silver salt photothermographic dry imaging material, a large endothermic peak is present at a position lower than the Tg value of the binder resin used in the photosensitive layer. Appear. As a result of diligent investigation focusing on this thermal transition point temperature, by setting the thermal transition point temperature to 46 ° C. or higher and 200 ° C. or lower, not only the fastness of the formed coating film is increased, but also the sensitivity, maximum The inventors have newly found that photographic performance such as density and image storage stability is greatly improved, and have reached the present invention.

  The glass transition temperature (Tg) was obtained by the method described in “Polymer Handbook” pages III-139 to III-179 (1966, Wiley and Sun, Inc.) by Brandrup et al. Tg in the case of a polymer resin is obtained by the following formula.

Tg (copolymer) (° C.) = V ₁ Tg ₁ + v ₂ Tg ₂ +... + V _n Tg _{n
Wherein, v 1, v 2 ··· v} n represents the mass fraction of the monomer in the _{copolymer, Tg 1, Tg 2 ··· Tg} n are each monomer in the copolymer Tg (° C.) of a single polymer obtained from the body. ]
The accuracy of Tg calculated according to the above equation is ± 5 ° C.

  In the silver salt photothermographic dry imaging material of the present invention, as the binder contained in the photosensitive layer containing aliphatic carboxylic acid silver salt, photosensitive silver halide grains, reducing agent, etc. on the support, a conventionally known high Molecular compounds can be used. The Tg is 70 to 105 ° C., the number average molecular weight is 1,000 to 1,000,000, preferably 10,000 to 500,000, and the degree of polymerization is about 50 to 1,000. Examples of such include vinyl chloride, vinyl acetate, vinyl alcohol, maleic acid, acrylic acid, acrylic ester, vinylidene chloride, acrylonitrile, methacrylic acid, methacrylic ester, styrene, butadiene, ethylene, vinyl butyral, vinyl acetal, There are compounds made of a polymer or copolymer containing an ethylenically unsaturated monomer such as vinyl ether as a constituent unit, polyurethane resins, and various rubber resins.

  Moreover, phenol resin, epoxy resin, polyurethane curable resin, urea resin, melamine resin, alkyd resin, formaldehyde resin, silicone resin, epoxy-polyamide resin, polyester resin, and the like can be given. These resins are described in detail in “Plastic Handbook” issued by Asakura Shoten. There is no restriction | limiting in particular in these high molecular compounds, A homopolymer or a copolymer may be sufficient if the glass transition temperature (Tg) of the induced | guided | derived polymer exists in the range of 70-105 degreeC.

  Polymers or copolymers containing such ethylenically unsaturated monomers as structural units include acrylic acid alkyl esters, acrylic acid aryl esters, methacrylic acid alkyl esters, methacrylic acid aryl esters, alkyl cyanoacrylates. Ester, cyanoacrylic acid aryl ester and the like, and the alkyl group and aryl group thereof may or may not be substituted. Specifically, methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, sec-butyl, tert-butyl, amyl, hexyl, cyclohexyl, benzyl, chlorobenzyl, octyl, stearyl, sulfopropyl, N-ethyl-phenylaminoethyl, 2- (3-phenylpropyloxy) ethyl , Dimethyl Minophenoxyethyl, furfuryl, tetrahydrofurfuryl, phenyl, cresyl, naphthyl, 2-hydroxyethyl, 4-hydroxybutyl, triethylene glycol, dipropylene glycol, 2-methoxyethyl, 3-methoxybutyl, 2-acetoxyethyl, 2 -Acetoacetoxyethyl, 2-ethoxyethyl, 2-iso-propoxyethyl, 2-butoxyethyl, 2- (2-methoxyethoxy) ethyl, 2- (2-ethoxyethoxy) ethyl, 2- (2-butoxyethoxy) Examples thereof include ethyl, 2-diphenylphosphorylethyl, ω-methoxypolyethylene glycol (addition mole number n = 6), allyl, dimethylaminoethylmethyl chloride salt and the like.

  In addition, the following monomers can be used. Specific examples of vinyl esters include vinyl acetate, vinyl propionate, vinyl butyrate, vinyl isobutyrate, vinyl caproate, vinyl chloroacetate, vinyl methoxyacetate, vinyl phenyl acetate, vinyl benzoate, vinyl salicylate. N-substituted acrylamides, N-substituted methacrylamides and acrylamides, methacrylamides: N-substituents include methyl, ethyl, propyl, butyl, tert-butyl, cyclohexyl, benzyl, hydroxymethyl, methoxyethyl, dimethyl Aminoethyl, phenyl, dimethyl, diethyl, β-cyanoethyl, N- (2-acetoacetoxyethyl), diacetone and the like; olefins: for example, dicyclopentadiene, ethylene, propylene, 1- Ten, 1-pentene, vinyl chloride, vinylidene chloride, isoprene, chloroprene, butadiene, 2,3-dimethylbutadiene, etc .; styrenes: for example, methylstyrene, dimethylstyrene, trimethylstyrene, ethylstyrene, isopropylstyrene, tert-butylstyrene , Chloromethyl styrene, methoxy styrene, acetoxy styrene, chloro styrene, dichloro styrene, bromo styrene, vinyl benzoic acid methyl ester, etc .; vinyl ethers: for example, methyl vinyl ether, butyl vinyl ether, hexyl vinyl ether, methoxyethyl vinyl ether, dimethylaminoethyl vinyl ether N-substituted maleimides: As N-substituent, methyl, ethyl, propyl, butyl, tert-butyl, cyclohexyl , Benzyl, n-dodecyl, phenyl, 2-methylphenyl, 2,6-diethylphenyl, 2-chlorophenyl, etc .; others include butyl crotonate, hexyl crotonate, dimethyl itaconate, dibutyl itaconate , Diethyl maleate, dimethyl maleate, dibutyl maleate, diethyl fumarate, dimethyl fumarate, dibutyl fumarate, methyl vinyl ketone, phenyl vinyl ketone, methoxyethyl vinyl ketone, glycidyl acrylate, glycidyl methacrylate, N-vinyl oxazolidone, N -Vinylpyrrolidone, acrylonitrile, methacrylonitrile, methylenemalonnitrile, vinylidene chloride and the like can be mentioned.

  Among these, particularly preferred examples include methacrylic acid alkyl esters, methacrylic acid aryl esters, styrenes, and the like. Among such polymer compounds, it is preferable to use a polymer compound having an acetal group. The polymer compound having an acetal group is preferable because it is excellent in compatibility with the aliphatic carboxylic acid to be produced and has a great effect of preventing the film from being softened.

  As the polymer compound having an acetal group, a compound represented by the following general formula (V) is particularly preferable.

[Wherein, R ₁ represents an alkyl group, a substituted alkyl group, an aryl group or a substituted aryl group, but is preferably a group other than an aryl group. R ₂ represents an unsubstituted alkyl group, a substituted alkyl group, an unsubstituted aryl group, a substituted aryl group, —COR ₃ or —CONHR ₃ . R ₃ has the same meaning as R ₁ . ]
The unsubstituted alkyl group represented by R ₁ , R ₂ , or R ₃ is preferably an alkyl group having 1 to 20 carbon atoms, particularly preferably 1 to 6 carbon atoms. These may be linear or branched, and preferably a linear alkyl group. Examples of such unsubstituted alkyl groups include methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, t-butyl, n-amyl, t-amyl, n -Hexyl group, cyclohexyl group, n-heptyl group, n-octyl group, t-octyl group, 2-ethylhexyl group, n-nonyl group, n-decyl group, n-dodecyl group, n-octadecyl group, etc. Is particularly preferably a methyl group or a propyl group.

  As an unsubstituted aryl group, a C6-C20 thing is preferable, for example, a phenyl group, a naphthyl group, etc. are mentioned. Examples of the group that can be substituted with the above alkyl group or aryl group include an alkyl group (for example, a methyl group, an n-propyl group, a t-amyl group, a t-octyl group, an n-nonyl group, a dodecyl group), an aryl group. (For example, phenyl group), nitro group, hydroxyl group, cyano group, sulfo group, alkoxy group (for example, methoxy group), aryloxy group (for example, phenoxy group), acyloxy group (for example, acetoxy group), Acylamino group (for example, acetylamino group), sulfonamide group (for example, methanesulfonamide group), sulfamoyl group (for example, methylsulfamoyl group), halogen atom (for example, fluorine atom, chlorine atom, bromine atom) ), Carboxy group, carbamoyl group (for example, methylcarbamoyl group, etc.), alkoxycarbonyl group (for example, metho Shiruboniru group), a sulfonyl group (e.g., methyl sulfonyl group). When there are two or more substituents, they may be the same or different. The total carbon number of the substituted alkyl group is preferably 1-20, and the total carbon number of the substituted aryl group is preferably 6-20.

The R _2, -COR ₃ (R ₃ is an alkyl group or an aryl group), - CONHR ₃ (R ₃ is an aryl group). a, b, and c are values representing the mass of each repeating unit in mol (mol)%, a is 40 to 86 mol%, b is 0 to 30 mol%, and c is in the range of 0 to 60 mol%. A + b + c = 100 mol%, particularly preferably a is in the range of 50 to 86 mol%, b is 5 to 25 mol%, and c is 0 to 40 mol%. Each repeating unit having a composition ratio of a, b, and c may be composed of only the same one or different ones.

As the polyurethane resin that can be used in the present invention, known resins such as polyester polyurethane, polyether polyurethane, polyether polyester polyurethane, polycarbonate polyurethane, polyester polycarbonate polyurethane, and polycaprolactone polyurethane can be used. For all of the polyurethane shown here, if _{necessary, -COOM, -SO 3 M, -OSO} 3 M, -P = O (OM) 2, -O-P = O (OM) 2, (M is hydrogen An atom or an alkali metal base), —N (R ₄ ) ₂ , —N + (R ₄ ) ₃ (R ₄ represents a hydrocarbon group, and a plurality of R ₄ may be the same or different), epoxy It is preferable to use one in which at least one polar group selected from a group, —SH, —CN and the like is introduced by copolymerization or addition reaction. The amount of such a polar group is 10 ⁻¹ to 10 ⁻⁸ mol / g, preferably 10 ⁻² to 10 ⁻⁶ mol / g. In addition to these polar groups, it is preferable to have at least one OH group in total at least one at the polyurethane molecule end. Since OH groups are cross-linked with polyisocyanate which is a curing agent to form a three-dimensional network structure, it is more preferable that the OH groups are contained in the molecule. In particular, it is preferable that the OH group is at the molecular end because the reactivity with the curing agent is high. The polyurethane preferably has 3 or more OH groups at the molecular terminals, and particularly preferably 4 or more. When polyurethane is used, the glass transition temperature is preferably 70 to 105 ° C., the elongation at break is 100 to 2000%, and the stress at break is preferably 0.5 to 100 N / mm ² .

  In the present invention, the polymer compound represented by the general formula (V) is synthesized by a general synthesis method described in “vinyl acetate resin” edited by Ichiro Sakurada (Polymer Chemistry Publishing Society, 1962) and the like. Can do. As a typical synthesis method, Synthesis Example 1 described in paragraph No. 0208 of JP-A No. 2002-365756 can be mentioned. Other polymer compounds (polymers) listed in Table 1 were synthesized in the same manner.

  These polymer compounds may be used alone as a binder, or two or more kinds may be blended and used. In the photosensitive silver salt-containing layer (preferably photosensitive layer) of the present invention, the above polymer is used as a main binder. The main binder as used herein refers to “a state in which the polymer occupies 50% by mass or more of the total binder of the photosensitive silver salt-containing layer”. Therefore, other polymers may be blended and used within a range of less than 50% by weight of the total binder. These polymers are not particularly limited as long as the polymers of the present invention are soluble. More preferably, polyvinyl acetate, a polyacrylic resin, a urethane resin, etc. are mentioned.

  Below, the structure of the high molecular compound preferably used for this invention is shown. In the table, Tg is a value measured by a differential scanning calorimeter (DSC) manufactured by Seiko Instruments Inc.

  In Table 1, P-9 is a polyvinyl butyral resin B-79 manufactured by Solusia.

  In the present invention, it is known that the use of a crosslinking agent with respect to the binder improves the film formation and reduces development unevenness. However, it prevents fogging during storage and produces printed silver after development. There is also an inhibitory effect.

  Examples of the crosslinking agent used in the present invention include various crosslinking agents conventionally used for silver halide photographic light-sensitive materials, such as aldehyde-based, epoxy-based, and ethyleneimine described in JP-A-50-96216. , Vinyl sulfone, sulfonic acid ester, acryloyl, carbodiimide, and silane compound crosslinking agents may be used, but the following isocyanate compounds, silane compounds, epoxy compounds, or acid anhydrides are preferred.

  An isocyanate-based and thioisocyanate-based crosslinking agent represented by the following general formula [IC], which is one of the preferable ones, will be described.

General formula [IC] X = C = N-L- (N = C = X) _v
In the formula, v is 1 or 2, L is an alkyl group, an alkenyl group, an aryl group or an alkylaryl group, a v + 1 valent linking group, and X is an oxygen or sulfur atom.

  In the compound represented by the above general formula [IC], the aryl ring of the aryl group may have a substituent. Examples of preferred substituents are selected from halogen atoms (for example, bromine atoms or chlorine atoms), hydroxyl groups, amino groups, carboxyl groups, alkyl groups and alkoxy groups.

  The isocyanate-based crosslinking agent includes isocyanates having at least two isocyanate groups and adducts thereof (adducts), and more specifically, aliphatic diisocyanates and aliphatic diisocyanates having a cyclic group. Benzene diisocyanates, naphthalene diisocyanates, biphenyl isocyanates, diphenylmethane diisocyanates, triphenylmethane diisocyanates, triisocyanates, tetraisocyanates, adducts of these isocyanates and divalent or trivalent with these isocyanates Examples include adducts with polyalcohols.

  As specific examples, isocyanate compounds described on pages 10 to 12 of JP-A-56-5535 can be used.

  Note that the adduct body of isocyanate and polyalcohol has particularly high ability to improve interlayer adhesion, and prevent layer peeling, image shift, and bubble generation. Such isocyanates may be placed in any part of the silver salt photothermographic dry imaging material. For example, the photosensitivity of the support in the support (especially when the support is paper, it can be included in the size composition), photosensitive layer, surface protective layer, intermediate layer, antihalation layer, subbing layer, etc. It can be added to any layer on the layer side, and can be added to one or more of these layers.

  As the thioisocyanate-based crosslinking agent that can be used in the present invention, compounds having a thioisocyanate structure corresponding to the above-mentioned isocyanates are also useful.

  The amount of the crosslinking agent used in the present invention is in the range of 0.001 to 2 mol, preferably 0.005 to 0.5 mol, with respect to 1 mol of silver.

  The isocyanate compound and thioisocyanate compound that can be contained in the present invention are preferably compounds that function as the above-mentioned crosslinking agent. However, in the above general formula, v is zero (0), that is, the functional group is one. Even if it is a compound which has only, a good result is obtained.

  As an example of the silane compound which can be used as a crosslinking agent in this invention, the compound represented by General formula (1) or General formula (2) described in Unexamined-Japanese-Patent No. 2002-22203 is mentioned.

  The epoxy compound that can be used as the crosslinking agent is not particularly limited as long as it has one or more epoxy groups and the number of epoxy groups, molecular weight, and the like. The epoxy group is preferably contained in the molecule as a glycidyl group via an ether bond or an imino bond. Moreover, any of a monomer, an oligomer, a polymer, etc. may be sufficient as an epoxy compound, and the number of the epoxy groups which exist in a molecule | numerator is about 1-10 normally, Preferably it is 2-4. When the epoxy compound is a polymer, it may be a homopolymer or a copolymer, and the particularly preferred range of the number average molecular weight Mn is about 2000 to 20000.

  As an epoxy compound, the compound represented by the following general formula (EP) is preferable.

In the general formula (EP), the substituent of the alkylene group represented by R is preferably a group selected from a halogen atom, a hydroxyl group, a hydroxyalkyl group, or an amino group. The linking group represented by R preferably has an amide linking moiety, an ether linking moiety, or a thioether linking moiety. -SO ₂ Examples of the divalent linking group represented by _{X 1 -, - SO 2 NH} -, - S -, - O-, or -NR ₁₁ - are preferred. Here, R ₁₁ is a monovalent group and is preferably an electron withdrawing group.

These epoxy compounds may be used alone or in combination of two or more. The addition amount is not particularly limited, but is preferably in the range of 1 × 10 ⁻⁶ to 1 × 10 ⁻² mol / m ² , more preferably in the range of 1 × 10 ⁻⁵ to 1 × 10 ⁻³ mol / m ² . It is.

  The epoxy compound can be added to any layer on the photosensitive layer side of the support, such as a photosensitive layer, a surface protective layer, an intermediate layer, an antihalation layer, an undercoat layer, and one or two of these layers. It can be added to the above. Moreover, it can add to the arbitrary layer on the opposite side to the photosensitive layer of a support body collectively. In addition, any layer may be sufficient in the type of photosensitive material in which a photosensitive layer exists on both surfaces.

  An acid anhydride is a compound having at least one acid anhydride group represented by the following structural formula.

-CO-O-CO-
The acid anhydride is not particularly limited as long as it has one or more acid anhydride groups, and the number, molecular weight, and the like of the acid anhydride groups are not limited, but a compound represented by the following general formula (SA) is preferable.

  In the general formula (SA), Z represents an atomic group necessary for forming a monocyclic or polycyclic system. These ring systems may be unsubstituted or substituted. Examples of substituents include alkyl groups (eg, methyl, ethyl, hexyl), alkoxy groups (eg, methoxy, ethoxy, octyloxy), aryl groups (eg, phenyl, naphthyl, tolyl), hydroxyl groups, aryloxy groups (Eg, phenoxy), alkylthio group (eg, methylthio, butylthio), arylthio group (eg, phenylthio), acyl group (eg, acetyl, propionyl, butyryl), sulfonyl group (eg, methylsulfonyl, phenylsulfonyl), acylamino group Sulfonylamino group, acyloxy group (for example, acetoxy, benzoxy), carboxyl group, cyano group, sulfo group, and amino group. As the substituent, those not containing a halogen atom are preferable.

These acid anhydrides may be used alone or in combination of two or more. The addition amount is not particularly limited, but is preferably in the range of 1 × 10 ⁻⁶ to 1 × 10 ⁻² mol / m ² , more preferably in the range of 1 × 10 ⁻⁵ to 1 × 10 ⁻³ mol / m ² . It is.

  In the present invention, the acid anhydride can be added to any layer on the photosensitive layer side of the support, such as a photosensitive layer, a surface protective layer, an intermediate layer, an antihalation layer, and an undercoat layer. It can be added to a layer or two or more layers. Moreover, you may add to the same layer as the said epoxy compound.

[Silver halide grains]
Photosensitive silver halide grains (hereinafter also simply referred to as silver halide grains) used in the silver salt photothermographic dry imaging material of the present invention will be described.

  The photosensitive silver halide grains in the present invention can inherently absorb light as an intrinsic property of silver halide crystals, or artificially physicochemically emit visible light or infrared light. Physicochemical changes can occur in the silver halide crystal or on the crystal surface when absorbing light in any region within the light wavelength range from the ultraviolet light region to the infrared light region. The silver halide crystal grains processed and manufactured as described above.

  The silver halide grains themselves used in the present invention are P.I. Chifie et Physique Photographic (published by Paul Montel, 1967) by Glafkides. F. Duffin's Photographic Emission Chemistry (published by The Focal Press, 1966), V.C. L. It can be prepared as a silver halide grain emulsion using the method described in Making and Coating Photographic Emulsion (published by The Focal Press, 1964) by Zelikman et al. That is, any of an acidic method, a neutral method, an ammonia method, etc. may be used, and the formation of reacting a soluble silver salt and a soluble halogen salt may be any one of a one-side mixing method, a simultaneous mixing method, and a combination thereof. Of these methods, the so-called controlled double jet method, in which silver halide grains are prepared while controlling the formation conditions, is preferred.

  The halogen composition is not particularly limited and may be any of silver chloride, silver chlorobromide, silver chloroiodobromide, silver bromide, silver iodobromide, and silver iodide. Silver halide is particularly preferred.

  In the case of silver iodobromide, the iodine content is preferably in the range of 0.02 to 16 mol% / Agmol. Even if iodine is contained so as to be distributed throughout the silver halide grains, the iodine concentration in a specific portion of the silver halide grains, for example, the central portion of the grains is increased, and the concentration in the vicinity of the surface is decreased or substantially reduced. It may be a core / shell structure that is zero.

  The silver halide grains used in the present invention preferably have a smaller grain size of the silver halide grains in order to keep white turbidity and color tone (yellowishness) after image formation low and to obtain good image quality. As a value when particles having a diameter of less than 0.02 μm are excluded from measurement, 0.030 μm or more and 0.055 μm or less are preferable.

  Here, the grain size means the length of the edge of the silver halide grain when the silver halide grain is a so-called normal crystal of a cube or octahedron. Further, when the silver halide grain is a tabular grain, it means the diameter when converted into a circular image having the same area as the projected area of the main surface.

  In the present invention, the silver halide grains are preferably monodispersed. The term “monodispersed” as used herein means that the coefficient of variation of the particle diameter obtained by the following formula is 30% or less. Preferably it is 20% or less, More preferably, it is 15% or less.

Coefficient of variation of particle size = standard deviation of particle size / average value of particle size × 100 (%)
Examples of the shape of the silver halide grains include cubes, octahedrons, tetradecahedral grains, tabular grains, spherical grains, rod-shaped grains, and potato grains. Among these, in particular, cubic, octahedral, Tetrahedral and tabular silver halide grains are preferred.

  When tabular silver halide grains are used, the average aspect ratio is preferably 1.5 or more and 100 or less, more preferably 2 or more and 50 or less. These are described in US Pat. Nos. 5,264,337, 5,314,798, 5,320,958, etc., and the desired tabular grains can be easily obtained.

  The silver halide grains of the present invention may be added to the photosensitive layer by any method. At this time, the silver halide grains are arranged so as to be close to a reducible silver source (aliphatic carboxylic acid silver salt). However, it is preferable to obtain an imaging material with high sensitivity and high covering power (CP).

[Non-photosensitive aliphatic carboxylic acid silver salt]
The non-photosensitive aliphatic carboxylic acid silver salt according to the present invention is a reducible silver source, and a silver salt of a long-chain aliphatic carboxylic acid having 10 to 30, preferably 15 to 25 carbon atoms is preferable. Examples of suitable silver salts include the following.

  Examples thereof include silver salts such as gallic acid, succinic acid, behenic acid, stearic acid, arachidic acid, palmitic acid and lauric acid, and preferable silver salts include silver behenate, silver arachidate and silver stearate.

  In the present invention, it is preferable that two or more kinds of aliphatic carboxylic acid silver salts are mixed in order to improve developability and form a silver image having a high density and a high contrast. It is preferable to prepare by mixing a silver ion solution with an aromatic carboxylic acid mixture.

  On the other hand, from the viewpoint of the storage stability of the image after development, the melting point of the aliphatic carboxylic acid which is a raw material for the aliphatic carboxylate silver is 50 ° C or higher, preferably 60 ° C or higher. The content ratio is preferably 50% or more, preferably 70% or more, and more preferably 80% or more. From this viewpoint, specifically, it is preferable that the content of silver behenate is high.

  The aliphatic carboxylic acid silver salt is obtained by mixing a water-soluble silver compound and a compound that forms a complex with silver, and is described in Japanese Patent Application Laid-Open No. 9-127643. The controlled double jet method as described above is preferably used. For example, an alkali metal salt (eg, sodium hydroxide, potassium hydroxide, etc.) is added to an organic acid to produce an organic acid alkali metal salt soap (eg, sodium behenate, sodium arachidate), and then a controlled double jet. According to the method, the soap and silver nitrate are mixed to produce an aliphatic carboxylic acid silver salt crystal. At that time, seed crystal grains of silver aliphatic carboxylate, silver halide grains, and the like may be mixed.

  Examples of the alkali metal salt used in the present invention include sodium hydroxide, potassium hydroxide, and lithium hydroxide, but it is preferable to use sodium hydroxide and potassium hydroxide in combination. The combined ratio is preferably such that the molar ratio of both of the above-mentioned hydroxide salts is in the range of 10:90 to 75:25. When used in the above range when reacted with an aliphatic carboxylic acid to form an alkali metal salt of an aliphatic carboxylic acid, the viscosity of the reaction solution can be controlled in a good state.

  In addition, when preparing an aliphatic carboxylate silver salt in the presence of silver halide grains having an average particle diameter of 0.050 μm or less, the alkali metal of the alkali metal salt is preferably a halide having a higher potassium ratio. It is preferable because dissolution of silver particles and Ostwald ripening are prevented. Moreover, the size of fatty acid silver salt particle | grains can be made small, so that the ratio of potassium salt is high. A preferable ratio of the potassium salt is 50 to 100% based on the total alkali metal salt used in the step of producing the aliphatic carboxylate. The concentration of the alkali metal salt is preferably 0.1 to 0.3 mol / 1000 ml.

  In the aliphatic carboxylic acid silver salt according to the present invention, the average equivalent circle diameter is preferably 0.05 μm or more and 0.8 μm or less, and the average thickness is preferably 0.005 μm or more and 0.07 μm or less. Particularly preferably, the average equivalent circle diameter is not less than 0.2 μm and not more than 0.5 μm, and the average thickness is not less than 0.01 μm and not more than 0.05 μm.

  When the average equivalent circle diameter is 0.05 μm or less, the transparency is excellent, but the image storage stability is poor, and when the average particle diameter is 0.8 μm or more, devitrification is severe. When the average thickness is 0.005 μm or less, the surface area is large, and silver ions are rapidly supplied during development. In particular, the low density area is not used for silver images, and there is a large amount of silver ions remaining in the film. The image storage stability is significantly deteriorated. On the other hand, when the average thickness is 0.07 μm or more, the surface area is reduced and the image stability is improved. However, the silver supply during development is slow, and the developed silver shape is uneven in the high density portion, resulting in the highest result. Concentration tends to be low.

  The method for obtaining the aliphatic carboxylic acid silver salt particles having the above-mentioned shape is not particularly limited. For example, the mixed state at the time of forming the organic acid alkali metal salt soap or the mixed state at the time of adding silver nitrate to the soap. It is effective to keep it good, and to set the ratio of the organic acid to the soap and the ratio of the silver nitrate that reacts with the soap optimally.

  In the present invention, tabular aliphatic carboxylic acid silver salt particles (aliphatic carboxylic acid having an average equivalent circle diameter of 0.05 μm to 0.8 μm and an average thickness of 0.005 μm to 0.07 μm) The acid silver salt particles) are preferably pre-dispersed with a binder, a surfactant or the like, if necessary, and then dispersed and ground with a media disperser or a high-pressure homogenizer. As the preliminary dispersion method, for example, a general stirrer such as an anchor type or a propeller type, a high speed rotary centrifugal radiation type stirrer (dissolver), or a high speed rotary shear type stirrer (homomixer) can be used.

  Further, as the media disperser, for example, a rolling mill such as a ball mill, a planetary ball mill, a vibrating ball mill, a bead mill that is a medium agitation mill, an attritor, and other basket mills can be used, and as a high-pressure homogenizer Various types can be used, such as a type that collides with a wall, a plug, etc., a type in which liquids are collided with each other at high speed, and a type through which a thin orifice is passed.

  Ceramics used for the ceramic beads used when dispersing media include yttrium-stabilized zirconia and zirconia-reinforced alumina (ceramics containing these zirconia) because of the low generation of impurities due to friction with the beads and the dispersing machine during dispersion. Is abbreviated as zirconia in the following).

  In the apparatus used for dispersing the tabular aliphatic carboxylate silver salt particles according to the present invention, examples of the material of the member in contact with the aliphatic carboxylate silver salt particles include zirconia, alumina, silicon nitride, and boron nitride. It is preferable to use ceramics such as the above or diamond, and it is preferable to use zirconia. When the above dispersion is performed, the binder concentration is preferably added in an amount of 0.1 to 10% of the mass of the aliphatic silver carboxylate, and it is preferable that the liquid temperature does not exceed 45 ° C. from the preliminary dispersion through the main dispersion. As preferable operating conditions for this dispersion, for example, when a high-pressure homogenizer is used as the dispersing means, 29 to 100 MPa, and the number of operations is preferably 2 or more. Moreover, when using a media disperser as a dispersion | distribution means, a peripheral speed of 6-13 m / sec is mentioned as a preferable condition.

  In the present invention, it is preferable that the non-photosensitive aliphatic carboxylic acid silver salt particles are formed in the presence of a compound that functions as a crystal growth inhibitor or a dispersant. Moreover, it is preferable that the compound which functions as a crystal growth inhibitor or a dispersing agent is an organic compound having a hydroxyl group or a carboxyl group.

  In the present invention, the compound that functions as a crystal growth inhibitor or dispersant for the aliphatic carboxylate silver particles refers to a silver aliphatic carboxylate under the conditions in which the compound coexists in the production process of the aliphatic carboxylate particles. A compound having a function and an effect of reducing the particle size or monodispersing than when it is produced under conditions that do not coexist. Specific examples include monohydric alcohols having 10 or less carbon atoms, preferably secondary alcohols, tertiary alcohols, glycols such as ethylene glycol and propylene glycol, polyethers such as polyethylene glycol, and glycerin. A preferable addition amount is 10 to 200% by mass with respect to the aliphatic carboxylate silver.

[Silver ion reducing agent]
In the present invention, US Pat. Nos. 3,589,903, 4,021,249 or British Patent 1,486,148 are used as silver ion reducing agents (sometimes referred to simply as reducing agents). And polyphenol compounds described in JP-A-51-51933, JP-A-50-36110, JP-A-50-116023, JP-A-52-84727 or JP-B-51-35727, such as 2,2′-dihydroxy- Bisnaphthols described in US Pat. No. 3,672,904 such as 1,1′-binaphthyl, 6,6′-dibromo-2,2′-dihydroxy-1,1′-binaphthyl, For example, 4-benzenesulfonamidophenol, 2-benzenesulfonamidophenol, 2,6-dichloro-4-benzenesulfonamidophenol , It can be used sulfonamidophenols or sulfonamidonaphthols, such as described in U.S. Patent No. 3,801,321, such as 4-benzenesulfonamide naphthol.

[Coating aids, etc.]
In the present invention, the surface layer of the silver salt photothermographic dry imaging material (when the photosensitive layer side or the non-photosensitive layer is provided on the opposite side of the photosensitive layer with the support sandwiched) is handled before development. It is preferable to contain a matting agent in order to prevent scratches on the image after heat development, and 0.1 to 30% by mass with respect to the binder.

  The material of the matting agent may be either organic or inorganic. Examples of inorganic substances include silica described in Swiss Patent No. 330,158 and the like, glass powder described in French Patent No. 1,296,995 and the like, and alkali described in British Patent No. 1,173,181 and the like. Earth metals or carbonates such as cadmium and zinc can be used as the matting agent. Examples of organic substances include starch described in U.S. Pat. No. 2,322,037 and the like, starch derivatives described in Belgian Patent 625,451 and British Patent 981,198, and Japanese Patent Publication No. 44-3643. Polyvinyl alcohol described, polystyrene or polymethacrylate described in Swiss Patent No. 330,158, polyacrylonitrile described in US Pat. No. 3,079,257, US Pat. No. 3,022,169 etc. An organic matting agent such as a polycarbonate can be used.

[Fluorosurfactant]
Examples of the fluorine-based surfactant that can be used in the silver salt photothermographic dry imaging material of the present invention include compounds 1-1 to 1- 1 described in paragraph numbers 0013 to 0019 of JP-A No. 2004-21084. 4 or 2-1 to 2-10 are preferable. The amount of the fluorosurfactant added is preferably 1 × 10 ⁻⁸ to 1 × 10 ⁻¹ mol per 1 m ^2, particularly preferably 1 × 10 ⁻⁵ to 1 × 10 ⁻² mol. If it is less than the former range, charging characteristics cannot be obtained, and if it exceeds the former range, the humidity dependence is large and the storage stability under high humidity deteriorates.

[Layer structure and coating conditions]
The silver salt photothermographic dry imaging material of the present invention is formed by preparing a coating liquid in which the above-described constituent layers are dissolved or dispersed in a solvent, and applying a plurality of these coating liquids simultaneously, followed by heat treatment. It is preferable. Here, "multiple simultaneous multi-layer coating" means that a coating solution for each constituent layer (for example, a photosensitive layer and a protective layer) is prepared, and each layer is repeatedly coated and dried when it is coated on a support. Rather, it means that each constituent layer can be formed in such a state that a multilayer coating and drying process can be performed simultaneously.

  There are no particular restrictions on the method of applying multiple layers of each constituent layer simultaneously, and for example, a known method such as a bar coater method, curtain coating method, dipping method, air knife method, hopper coating method, or extrusion coating method may be used. Can do. Of these, a pre-weighing type coating method called an extrusion coating method is more preferable. Since the extrusion coating method does not volatilize on the slide surface unlike the slide coating method, it is suitable for precision coating and organic solvent coating. Although this coating method has been described on the side having the photosensitive layer, the same applies to the case of coating with undercoating when providing the backcoat layer.

In the present invention, the silver coating amount is preferably 0.5 g / m ² or more and 2.0 g / m ² or less, more preferably 1.0 g / m ² or more and 1.5 g / m ² or less.

In the present invention, the silver equivalent of silver halide grains having a grain size of 0.030 μm or more and 0.055 μm or less in the silver halide grain emulsion has a silver coating amount of 0.5 g / m ² or more and 1.5 g. It is preferably 3% or more and 15% or less in the range of / m ² or less.

  Among the applied silver amount, those derived from silver halide preferably occupy 2 to 18%, more preferably 3 to 15%, based on the total silver amount.

In the present invention, the coating density of silver halide grains of 0.01 μm or more (equivalent particle diameter equivalent to sphere) is preferably 1 × 10 ¹⁴ particles / m ² or more and 1 × 10 ¹⁸ particles / m ² or less. Furthermore, 1 × 10 ¹⁵ pieces / m ² or more and 1 × 10 ¹⁷ pieces / m ² or less are preferable.

Furthermore, the coating density of the aliphatic carboxylic acid silver salt of the present invention is 10 ⁻¹⁷ g or more, 10 ⁻¹⁵ g or less, more preferably 10 μg per silver halide grain of 0.01 μm or more (equivalent particle diameter equivalent to sphere). ^-16 g or more and 10 ^-14 g or less is preferable.

  When coated under the conditions within the above range, it is preferable from the viewpoint of the optical maximum density of the silver image per fixed coated silver amount, that is, the silver coating amount (covering power) and the color tone of the silver image. Results are obtained.

[Exposure conditions]
In the exposure of the silver salt photothermographic dry imaging material of the present invention, it is desirable to use an appropriate light source for the color sensitivity imparted to the photosensitive material. For example, when the photosensitive material is sensitive to infrared light, it can be applied to any light source as long as it is in the infrared light range. However, the laser power is high and the photosensitive material can be transparent. In view of the above, an infrared semiconductor laser (780 nm, 820 nm) is more preferably used.

  In the present invention, the exposure is preferably performed by laser scanning exposure, but various methods can be adopted as the exposure method. For example, as a first preferred method, there is a method using a laser scanning exposure machine in which the angle formed by the exposure surface of the photosensitive material and the scanning laser beam is not substantially perpendicular.

  Here, “substantially not perpendicular” means that the angle closest to the vertical during laser scanning is preferably 55 degrees or more and 88 degrees or less, more preferably 60 degrees or more and 86 degrees or less, and further Preferably it is 65 degrees or more and 84 degrees or less, Most preferably, it is 70 degrees or more and 82 degrees or less.

  The beam spot diameter on the photosensitive material exposure surface when the laser beam is scanned onto the photosensitive material is preferably 200 μm or less, more preferably 100 μm or less. This is preferable in that the smaller the spot diameter, the smaller the angle of deviation of the laser incident angle from the vertical. The lower limit of the beam spot diameter is 10 μm. By performing such laser scanning exposure, it is possible to reduce image quality deterioration related to reflected light such as generation of interference fringe-like unevenness.

  As a second method, it is preferable to perform exposure using a laser scanning exposure machine that emits scanning laser light that is a vertical multi. Compared with a longitudinal single mode scanning laser beam, image quality degradation such as occurrence of interference fringe-like unevenness is reduced.

  In order to make it vertically multi-ply, methods such as using return light by multiplexing and applying high-frequency superposition are preferable. The vertical multi means that the exposure wavelength is not single, and the distribution of the exposure wavelength is usually 5 nm or more, preferably 10 nm or more. The upper limit of the exposure wavelength distribution is not particularly limited, but is usually about 60 nm.

In the image recording methods of the first and second aspects described above, the laser used for the scanning exposure is generally well-known solid laser such as ruby laser, YAG laser, glass laser; HeNe laser, Ar ion. Gas laser such as laser, Kr ion laser, CO ₂ laser, CO laser, HeCd laser, N ₂ laser, excimer laser; InGaP laser, AlGaAs laser, GaAsP laser, InGaAs laser, InAsP laser, CdSnP ₂ laser, GaSb laser, etc. Semiconductor lasers; chemical lasers, dye lasers, and the like can be selected and used in a timely manner, but among these, it is preferable to use a semiconductor laser having a wavelength of 600 to 1200 nm from the viewpoint of maintenance and the size of the light source. However, a semiconductor laser having an emission peak intensity in the range of 390 nm to 430 nm can also be used when the present invention is applied to a photosensitive material that utilizes the inherent photosensitive characteristics of silver halide grains.

  In addition, in a laser used in a laser imager or a laser image setter, the beam spot diameter on the material exposure surface when scanned with a silver salt photothermographic dry imaging material is generally 5 to 75 μm as a minor axis diameter, The major axis diameter is in the range of 5 to 100 μm, and the laser beam scanning speed can be set to an optimum value for each photosensitive material depending on the sensitivity and laser power at the laser oscillation wavelength unique to the silver salt photothermographic dry imaging material.

[Development conditions]
In the present invention, the development conditions vary depending on the equipment, equipment, or means used, but typically involve heating the imagewise exposed silver salt photothermographic dry imaging material at a suitable high temperature. . The latent image obtained after exposure is obtained by heating the silver salt photothermographic dry imaging material at a moderately high temperature (eg, about 100-200 ° C.) for a sufficient time (generally about 1 second to about 2 minutes). It can be developed. When the heating temperature is 100 ° C. or lower, sufficient image density cannot be obtained in a short time, and when the heating temperature is 200 ° C. or higher, the binder melts, and not only the image itself, such as transfer to a roller, but also adversely affects the transportability and the developing machine. Effect. By heating, a silver image is generated by an oxidation-reduction reaction between silver ions (which function as an oxidizing agent) supplied from an aliphatic carboxylic acid silver salt or the like and a reducing agent. This reaction process proceeds without any supply of treatment liquid such as water from the outside.

  The heating device, apparatus, and means may be a heating means typical as a heat generator using a hot plate, iron, hot roller, carbon, white titanium, or the like. More preferably, in the silver salt photothermographic dry imaging material provided with the protective layer of the present invention, the surface on the side having the protective layer is brought into contact with the heating means, and the heat treatment is performed for uniform heating and thermal efficiency. From the viewpoint of workability and the like, it is preferable that the surface is conveyed while being brought into contact with a heat roller, heated and developed.

  EXAMPLES Hereinafter, although an Example is given and this invention is demonstrated in detail, this invention is not limited to these.

Example 1
<< Preparation of undercoated photographic support >>
Corona discharge treatment of 8 W · min / m ^{2 was performed} on both sides of a biaxially stretched heat-fixed polyethylene terephthalate film with an optical density of 0.170 (measured with a Densitometer PDA-65 manufactured by Konica Corporation) in blue. The applied photographic support was subjected to subbing. That is, the undercoat coating liquid a-1 was applied to one surface of this photographic support so that the dry film thickness was 0.2 μm at 22 ° C. and 100 m / min, and dried at 140 ° C. to form an image. A layer side undercoat layer was formed (referred to as undercoat underlayer A-1). Moreover, the following undercoat coating liquid b-1 was applied to the opposite surface as a backing layer undercoat layer at 22 ° C. and 100 m / min so that the dry film thickness was 0.12 μm, and dried at 140 ° C. An undercoat conductive layer having an antistatic function (referred to as undercoat underlayer B-1) was applied on the backing layer side. A corona discharge of 8 W · min / m ² is applied to the upper surfaces of the subbing lower layer A-1 and the subbing lower layer B-1, and the surface pH shown in Table 3 below is obtained on the lower subbing lower layer A-1. The undercoating liquid a-2 is applied at 33 ° C. and 100 m / min so as to have a dry film thickness of 0.03 μm, and dried at 140 ° C. to form an undercoating upper layer A-2. The undercoat coating solution b-2 shown below was applied at 33 ° C. and 100 m / min so as to have a dry film thickness of 0.2 μm, and dried at 140 ° C. to obtain an undercoat upper layer B-2. In addition, on the back surface side, the following BC layer and each coating solution for the protective layer are sequentially applied and dried on the undercoat upper layer B-2 so as to have the stated amount (per 1 m ² ). A BC layer and a protective layer were formed, and the support was further heat-treated at 123 ° C. for 2 minutes, and wound up under conditions of 25 ° C. and 50% RH to prepare sublimed supports 1 to 7.

[Preparation of aqueous polyester A-1 solution]
35.4 parts by weight of dimethyl terephthalate, 33.63 parts by weight of dimethyl isophthalate, 17.92 parts by weight of dimethyl sodium 5-sulfoisophthalate, 62 parts by weight of ethylene glycol, 0.065 parts by weight of calcium acetate / monohydrate, After transesterification of 0.022 parts by mass of manganese acetate tetrahydrate under a nitrogen stream while distilling off methanol at 170 to 220 ° C., 0.04 parts by mass of trimethyl phosphate and a polycondensation catalyst were used. 0.04 parts by mass of antimony oxide and 6.8 parts by mass of 1,4-cyclohexanedicarboxylic acid were added, and at a reaction temperature of 220 to 235 ° C., a theoretical amount of water was distilled off for esterification.

  Thereafter, the inside of the reaction system was further depressurized and heated for about 1 hour, and finally subjected to polycondensation at 280 ° C. and 133 Pa or less for about 1 hour to synthesize aqueous polyester A-1. The obtained aqueous polyester A-1 had an intrinsic viscosity of 0.33, an average particle size of 40 nm, and Mw = 80000 to 100,000.

  Next, 850 ml of pure water was placed in a 2 L three-necked flask equipped with a stirring blade, a reflux condenser, and a thermometer, and 150 g of aqueous polyester A-1 was gradually added while rotating the stirring blade. After stirring for 30 minutes at room temperature, the mixture was heated to an internal temperature of 98 ° C. over 1.5 hours and dissolved at this temperature for 3 hours. After completion of the heating, the mixture was cooled to room temperature over 1 hour and allowed to stand overnight to prepare a 15% by mass aqueous polyester A-1 solution.

[Preparation of Modified Aqueous Polyester B-1-2 Solution]
Into a 3 L four-necked flask equipped with a stirring blade, a reflux condenser, a thermometer and a dropping funnel, 1900 ml of the 15% by mass aqueous polyester A-1 solution was placed, and the internal temperature was adjusted to 80 ° C. while rotating the stirring blade. Until heated. Into this, 6.52 ml of a 24% aqueous solution of ammonium peroxide was added, and a monomer mixture (28.5 g of glycidyl methacrylate, 21.4 g of ethyl acrylate, 21.4 g of methyl methacrylate) was dropped over 30 minutes, The reaction is continued for another 3 hours. Then, it cooled and filtered to 30 degrees C or less, and prepared the modified aqueous polyester B-1 solution (vinyl-type component modification | denaturation ratio 20 mass%) whose solid content concentration is 18 mass%.

  The solid content concentration was the same except that the vinyl modification ratio was 36% by mass and the modified components were styrene: glycidyl methacrylate: acetoacetoxyethyl methacrylate: n-butyl acrylate = 39.5: 40: 20: 0.5. An 18% by mass modified aqueous polyester B-2 solution (vinyl component modification ratio 20% by mass) was prepared.

[Production of Acrylic Polymer Latex C-1 to C-3]
Acrylic polymer latexes C-1 to C-3 having the monomer composition shown in the following table were synthesized by emulsion polymerization. The solid content concentration was 30% by mass.

<< Aqueous polymer containing polyvinyl alcohol unit >>
D-1: PVA-617 (Kuraray Co., Ltd. aqueous dispersion (solid content 5%): degree of saponification 95)
[Image forming layer side undercoat coating solution a-1]
Acrylic polymer latex C-3 (solid content 30%) 70.0 g
Water dispersion of ethoxylated alcohol and ethylene homopolymer (10% solids)
5.0g
Surfactant (A) 0.1g
Distilled water was added to make 1000 ml, and a coating solution was obtained.

<< Image Forming Layer Side Undercoat Layer Coating Solution a-2 >>
Modified aqueous polyester B-2 (18% by mass) 30.0 g
Surfactant (A) 0.1g
Spherical silica matting agent (Nippon Shokubai Co., Ltd. Sea Hoster KE-P50)
0.04g
pH control agent (1% NaOH aqueous solution and 1% acetic acid aqueous solution) Distilled water was added to the amount of pH shown in Table 3 or more to make 1000 ml, thereby preparing a coating solution.

[Backing layer side undercoat coating solution b-1]
Acrylic polymer latex C-1 (solid content 30%) 30.0 g
Acrylic polymer latex C-2 (solid content 30%) 7.6 g
SnO ₂ sol 180g
(SnO ₂ sol synthesized by the method described in Example 1 of Japanese Patent Publication No. 35-6616 was heated and concentrated so that the solid content concentration was 10% by mass, and then adjusted to pH = 10 with ammonia water)
Surfactant (A) 0.5g
PVA-613 (PVA manufactured by Kuraray Co., Ltd.) 5% by weight aqueous solution 0.4 g
Distilled water was added to make 1000 ml, and a coating solution was obtained.

[Backing layer side undercoat upper layer coating solution b-2]
Modified aqueous polyester B-1 (18% by mass) 145.0 g
Spherical silica matting agent (Nippon Shokubai Co., Ltd. Sea Hoster KE-P50)
0.2g
Surfactant (A) 0.1g
Distilled water was added to make 1000 ml, and a coating solution was obtained.

(BC layer composition)
PVB-1 (binder) 1.8g
C1 (dye) 1.2 × 10 ⁻⁵ mol (BC layer protective layer coating solution)
Cellulose acetate butyrate 1.1g
Matting agent (polymethyl methacrylate: average particle size 5 μm) 0.12 g
Antistatic agent: F-EO 250mg
Antistatic agent: F-DS1 30mg
The binder used was polyacetal, and methyl ethyl ketone (MEK) was used as the organic solvent. Polyacetal is obtained by saponifying 98% of polyvinyl acetate having a polymerization degree of 500 and then converting 86% of the remaining hydroxyl groups into butyral, which is referred to as PVB-1.

<< Preparation of photosensitive silver halide emulsion >>
(Solution A1)
Phenylcarbamoylated gelatin 88.3g
Compound A (* 1) (10% aqueous methanol solution) 10 ml
Potassium bromide 0.32g
Finish to 5429 ml with water (Solution B1)
0.67 mol / L silver nitrate aqueous solution 2635 ml
(Solution C1)
Potassium bromide 51.55g
Potassium iodide 1.47g
Finish to 660 ml with water (Solution D1)
Potassium bromide 154.9g
4.41 g of potassium iodide
K ₃ IrCl ₆ (equivalent to 4 × 10 ⁻⁵ mol / Ag) 50.0 ml
Finish to 1982 ml with water (Solution E1)
0.4 mol / L potassium bromide aqueous solution The following silver potential control amount (Solution F1)
Potassium hydroxide 0.71g
Finish to 20 ml with water (Solution G1)
56% acetic acid aqueous solution 18.0 ml
(Solution H1)
Anhydrous sodium carbonate 1.72 g
Finish to 151 ml with water (* 1) Compound A:
_{HO (CH 2 CH 2 O)} n (CH (CH 3) CH 2 O) 17 (CH 2 CH 2 O) m H
(M + n = 5-7)
Using the mixing stirrer described in JP-B-58-58288, the solution A1 was mixed with a 1/4 amount of the solution B1 and the total amount of the solution C1 at a temperature of 32 ° C. and a pAg of 8.09. Addition took 45 minutes to nucleate. After 1 minute, the entire amount of solution F1 was added. During this time, the pAg was adjusted as appropriate using the solution E1. After 6 minutes, 3/4 amount of the solution B1 and the whole amount of the solution D1 were added over 14 minutes and 15 seconds by the simultaneous mixing method while controlling the temperature at 32 ° C. and pAg 8.09. After stirring for 5 minutes, the temperature was raised to 40 ° C., the whole amount of the solution G1 was added, and the silver halide emulsion was precipitated. The supernatant was removed leaving 2000 ml of the sedimented portion, 10 L of water was added, and after stirring, the silver halide emulsion was sedimented again. The remaining portion of 1500 ml was left, the supernatant was removed, 10 L of water was further added, and after stirring, the silver halide emulsion was allowed to settle. After leaving 1500 ml of the sedimented portion and removing the supernatant, the solution H1 was added, the temperature was raised to 60 ° C., and the mixture was further stirred for 120 minutes. Finally, the pH was adjusted to 5.8, and water was added so that the amount was 1161 g per mol of silver to obtain an emulsion.

  This emulsion was monodispersed cubic silver iodobromide grains having an average grain size of 0.040 μm, a grain size variation coefficient of 12%, and a [100] face ratio of 92%.

<< Preparation of photosensitive layer coating solution >>
(Preparation of powdered aliphatic carboxylic acid silver salt A)
In 4720 ml of pure water, 117.7 g of behenic acid, 60.9 g of arachidic acid, 39.2 g of stearic acid and 2.1 g of palmitic acid were dissolved at 80 ° C. Next, 486.2 ml of a 1.5 mol / L potassium hydroxide aqueous solution was added, and 6.2 ml of concentrated nitric acid was added, followed by cooling to 55 ° C. to obtain a fatty acid potassium solution. While maintaining the temperature of the fatty acid potassium solution at 55 ° C., 347 ml of t-butyl alcohol was added and stirred for 20 minutes, and then 45.3 g of the above photosensitive silver halide emulsion 1 and 450 ml of pure water were added, Stir for 5 minutes.

  Next, 702.6 ml of a 1 mol / L silver nitrate solution was added over 2 minutes and stirred for 10 minutes to obtain an aliphatic carboxylic acid silver salt dispersion. Thereafter, the obtained aliphatic carboxylic acid silver salt dispersion was transferred to a water-washing container, deionized water was added and stirred, and then allowed to stand to float and separate the aliphatic carboxylic acid silver salt dispersion. Was removed. Thereafter, washing with deionized water and drainage were repeated until the electrical conductivity of the drainage reached 50 μS / cm, and centrifugal dehydration was carried out. Then, the cake-like aliphatic carboxylic acid silver salt thus obtained was added to the airflow dryer flash jet. Using a dryer (manufactured by Seishin Enterprise Co., Ltd.), drying is performed until the water content becomes 0.1% according to the operating conditions of the nitrogen gas atmosphere and the hot air temperature at the entrance of the dryer to obtain powdered aliphatic carboxylic acid silver salt A It was. An infrared moisture meter was used to measure the water content of the aliphatic carboxylic acid silver salt composition. The silveration rate of the aliphatic carboxylic acid silver was confirmed to be about 95% by the method described above.

(Preparation of preliminary dispersion A)
14.57 g of polyvinyl butyral resin P-9 was dissolved in 1457 g of methyl ethyl ketone (hereinafter abbreviated as MEK), and the powdered aliphatic carboxylic acid silver salt A was stirred with a dissolver DISPERMAT CA-40M manufactured by VMA-GETZMANN. Preliminary dispersion A was prepared by gradually adding 500 g and mixing well.

(Preparation of photosensitive emulsion dispersion A)
Media type dispersion filled with 80% of the internal volume of 0.5 mm diameter zirconia beads (Toreceram manufactured by Toray Industries, Inc.) using the prepared preliminary dispersion A so that the residence time in the mill is 1.5 minutes using a pump. A photosensitive emulsion dispersion A was prepared by supplying to a machine DISPERMAT SL-C12EX type (manufactured by VMA-GETZMANN) and dispersing at a mill peripheral speed of 8 m / s.

(Preparation of stabilizer solution)
A stabilizer solution was prepared by dissolving 1.0 g of Stabilizer 1 and 0.31 g of potassium acetate in 4.97 g of methanol.

(Preparation of infrared sensitizing dye liquid A)
19.2 mg of infrared sensitizing dye 1, 10 mg of infrared sensitizing dye 2, 1.48 g of 2-chloro-benzoic acid, 2.78 g of stabilizer 2 and 365 mg of 5-methyl-2-mercaptobenzimidazole Was dissolved in 31.3 ml of MEK in the dark to prepare an infrared sensitizing dye solution A.

(Preparation of additive solution a)
27.98 g and 1.54 g of 4-methylphthalic acid as 1,1-bis (2-hydroxy-3,5-dimethylphenyl) -3,5,5-trimethylhexane (developer A) as a developer, 0 20 g of the dye C1 was dissolved in 110 g of MEK to obtain an additive solution a.

(Preparation of additive liquid b)
3.56 g of antifoggant 2 and 3.43 g of phthalazine were dissolved in 40.9 g of MEK to obtain additive solution b.

(Preparation of photosensitive layer coating liquid A)
In an inert gas atmosphere (97% nitrogen), the photosensitive emulsion dispersion A (50 g) and 15.11 g of MEK were kept at 21 ° C. with stirring, and 390 μl of antifoggant 1 (10% methanol solution) was added, Stir for 1 hour. Further, 494 μl of calcium bromide (10% methanol solution) was added and stirred for 20 minutes. Subsequently, 167 ml of the stabilizer solution was added and stirred for 10 minutes, and then 1.32 g of the infrared sensitizing dye solution A was added and stirred for 1 hour. Thereafter, the temperature was lowered to 13 ° C. and further stirred for 30 minutes. While keeping the temperature at 13 ° C., 13.31 g of polyvinyl acetal resin P-1 as a binder resin was added and stirred for 30 minutes, and then 1.084 g of tetrachlorophthalic acid (9.4 mass% MEK solution) was added thereto. Stir for minutes. Further, while continuing stirring, 12.43 g of additive solution a, 1.6 ml of Desmodur N3300 / Mobey aliphatic isocyanate (10% MEK solution), and 4.27 g of additive solution b were sequentially added and stirred for photosensitivity. An aqueous layer coating solution A1 was obtained.

<Surface protective layer>
A coating solution having the following composition was prepared in the same manner as the photosensitive layer coating solution, and coated and dried on the photosensitive layer so as to have the following weight (per 1 m ² ) to form a photosensitive layer protective layer.

Cellulose acetate propionate 2.0g
4-methylphthalic acid 0.7g
Tetrachlorophthalic acid 0.2g
Tetrachlorophthalic anhydride 0.5g
Silica matting agent (average particle size 5μm) 0.5g
1,3-bis (vinylsulfonyl) -2-propanol 50mg
Benzotriazole 30mg
Antistatic agent: F-EO 20mg
Antistatic agent: F-DS1 3mg
《Preparation of silver salt photothermographic dry imaging material sample》
The photosensitive layer coating solution A and the surface protective layer coating solution prepared above are simultaneously applied on the undercoat layer A-2 of the prepared supports 1 to 7 using a known extrusion coater. Thus, silver salt photothermographic dry imaging material samples 1 to 7 were produced. The coating was carried out so that the photosensitive layer had an applied silver amount of 1.5 g / m ² and the surface protective layer had a dry film thickness of 2.5 μm. Thereafter, drying was performed for 10 minutes using a drying air having a drying temperature of 75 ° C. and a dew point temperature of 10 ° C.

<< Evaluation of each characteristic value >>
(Exposure and development processing)
From the photosensitive layer coating surface side of each sample produced as described above, exposure by laser scanning is given by an exposure machine using a semiconductor laser having a longitudinal multimode wavelength of 800 to 820 nm by high frequency superposition as an exposure source. It was. At this time, an image was formed by setting the angle of the exposure surface of the sample and the exposure laser beam to 75 degrees. In this method, an image with less unevenness and unexpectedly good sharpness or the like was obtained compared to the case where the angle was 90 degrees.

  Thereafter, using an automatic developing machine having a heat drum, the surface protective layer of the sample and the drum surface were in contact with each other, and heat development was performed at 123 ° C. for 15 seconds. At that time, exposure and development were performed in a room adjusted to 23 ° C. and 50% RH.

(Measurement of fog density)
The density of the formed image obtained as described above was measured using a densitometer, a characteristic curve consisting of horizontal axis-exposure amount and vertical axis-density was created, and the minimum density fog density (minimum density) was measured. .

(Evaluation of film on emulsion side after development)
The exposure was adjusted so that the finished density was 2.5, and development processing was performed. After 5 minutes from the time immediately after the film was discharged, film attachment on the emulsion surface was evaluated by the following method.

The film was scratched perpendicularly with a razor, a commercially available cello tape (registered trademark) was adhered thereto, and the area where the emulsion film was peeled off from the film when the tape was peeled off was evaluated.
Rank 5: Not peeled at all Rank 4: The peeled portion is less than 1/4 of the area where the tape is bonded Rank 3: The peeled portion is 1/4 or more and less than 1/2 of the area where the tape is bonded Rank 2: Peel The part where the tape is bonded is 1/2 or more and less than 3/4 of the area where the tape is adhered Rank 1: The part where the tape is peeled is 3/4 or more of the area where the tape is adhered. The results obtained are shown in Table 3.

  From Table 3, it can be seen that the sample of the present invention is a silver salt photothermographic dry imaging material having low fog and obtaining a sufficient strength with a film immediately after development processing.

Claims (2)

A silver salt photothermographic dry imaging material having a photosensitive layer containing a non-photosensitive aliphatic carboxylic acid silver salt particle, a photosensitive silver halide particle, a silver ion reducing agent, and a binder on a support. A silver salt photothermographic dry imaging material, wherein the film surface pH on the photosensitive layer side is 3.0 or more and less than 8.0. A coating liquid for photosensitive layer containing non-photosensitive aliphatic silver carboxylate particles, photosensitive silver halide particles, a silver ion reducing agent and a binder, and having a film surface pH of 3.0 or more and less than 8.0. A method for producing a silver salt photothermographic dry imaging material, which is produced by coating the substrate on a substrate and drying it.