JP3893426B2 - Method for producing thermal imaging material - Google Patents

Description

【０１２２】
(面状の評価)
得られた塗布物の面状を塗布幅10cm当たりに発生したスジの本数および塗布物の銀量（重量）の最大値と最小値で除した比によって示される塗布ムラの状態で評価した。スジの本数が少ないほど、また、銀量比が１．０に近いほど面状が良好であることを示す。
【０１２３】
(写真性能の評価)
647nmKrレーザー感光計(最大出力500mW)で法線に対して30度の斜度で感光材料を露光した後、感光材料を120℃で15秒間処理(現像)し、得られた画像の評価を濃度計により行った。測定の結果は、カブリ（Dmin）、感度(Dminより1.0高い濃度を与える露光量の比の逆数)で評価した。感度については感光材料3の感度を100とした。
【０１２４】
結果を表1に示す。本発明の領域で面状および写真性能いずれも良好であることがわかる。また、写真性能評価と同様に現像した感材に水を0.1cc滴下し、10秒後にふき取った際の後の様子を見て耐水性を評価したところいずれの感材も良好な耐水性を示し水跡は付かなかった。
【０１２５】
【表１】

【０１２６】
実施例２
実施例１の感光材料５の保護層２塗布液Ｐの調製の際に硬膜剤をスタチックミキサーを用い、感光材料５と同条件で添加混合して感光材料を調製し、実施例１と同様に評価したところ実施例1の感光材料５と同様の良好な面状と写真性能を示した。
【０１２７】
実施例３
実施例１の感光材料５の乳剤層塗布液にN-(2-メトキシフェニル)-N -ホルミルヒドラジンを塗布量1mg/m²となるように添加し、これ以外は同様にして感光材料を調製し、実施例１と同様に評価したところ良好な面状と写真性能を示した。
【０１２８】
実施例４
実施例１の感光材料５において乳剤層塗布液中のハロゲン化銀を添加せず、還元剤分散物の代わりに等モルの3,4-ジヒドロキシ安息香酸メチルを水溶液で添加し、さらにバック面の塩基液ならびに染料液を添加しなかったものを感熱材料とした。こうして得た感熱材料に対して90℃5秒で加熱し面状と色調を評価したところ良好な性能を示すことがわかった。
【０１２９】
【発明の効果】
本発明により、面状が良好で、画像形成能力、すなわち写真性能に優れた熱画像形成材料が得られる。
【図面の簡単な説明】
【図１】本発明で用いる硬膜剤含有親水性コロイド保護層塗布液混合攪拌機の概略図である。[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a method for producing a thermal image forming material, particularly a photothermographic material (hereinafter sometimes referred to as a photothermographic material).
[0002]
[Prior art]
In recent years, in the medical field, reduction of waste processing liquid has been strongly desired from the viewpoint of environmental protection and space saving. Therefore, photosensitive heat for medical diagnosis and photographic technology that can be efficiently exposed by a laser image setter or laser imager and can form a clear black image having high resolution and sharpness. There is a need for techniques relating to developed photographic materials. These photosensitive photothermographic materials can eliminate the use of solution processing chemicals and supply customers with a simpler heat development processing system that does not damage the environment.
[0003]
Although there is a similar requirement in the field of general image forming materials, medical images are required to have high image quality with excellent sharpness and graininess because they are required to be finely drawn, and are cooled from the viewpoint of ease of diagnosis. There is a feature that a black tone image is preferred. At present, various hard copy systems using pigments and dyes such as inkjet printers and electrophotography are generally distributed as modeling systems, but there is no satisfactory output system for medical images.
[0004]
On the other hand, thermal imaging systems using organic silver salts are disclosed in many documents including US Pat. No. 2910377 and Japanese Patent Publication No. 43-4924. Thermal image forming systems using these organic silver salts can achieve image quality and color tone that are satisfactory as medical images, but the uppermost layer is preferably gelatin from the viewpoint of the objectivity of the image forming material. However, gelatin is highly water-soluble and is not water resistant as it is. Therefore, it is conceivable to perform hardening using a known hardening technique. However, the hardening agent deteriorates the coatability and remarkably deteriorates the surface state.
[0005]
[Problems to be solved by the invention]
An object of the present invention is to provide a method for producing a thermal image forming material, in particular, a method for producing a photothermographic material, which is free of streak failure and coating unevenness and has a good surface shape, high sensitivity, low fog and excellent photographic performance. It is in.
[0006]
[Means for Solving the Problems]
This object has been achieved by the following means.
(1) Organic silver salt, reducing agent for silver ions , Photosensitive silver halide And a method for producing a thermal imaging material in which a thermal image forming layer coating solution containing a polymer latex and a hydrophilic colloid protective layer coating solution containing a hardener are applied sequentially or simultaneously and dried. The hardener is a compound selected from polyvalent metal ions, Apply the protective layer 10 A method for producing a thermal image forming material, comprising adding a hardening agent to the protective layer coating solution from before to immediately before.
(2) The method for producing a thermal image forming material according to the above (1), which is added from 10 minutes before to 10 seconds before applying the hardener.
[0007]
DETAILED DESCRIPTION OF THE INVENTION
The present invention is described in detail below. The thermal image forming material in the present invention has a thermal image forming layer containing an organic silver salt and a protective layer containing a hardener and a hydrophilic colloid as a binder. As the coating solution for the forming layer, one containing an organic silver salt, a reducing agent for silver ions and a polymer latex is used, and the thermal image forming layer coating solution and the coating solution for the protective layer are used sequentially (as needed) or By simultaneously applying, a thermal image forming layer and a protective layer are formed. In this case, the hardener should be added to the protective layer coating solution. 10 The period from the minute before to just before application, preferably the period from 10 minutes before application to 10 seconds before application. By regulating the addition time of the hardener in the protective layer coating solution as described above, there are no streak failures, and it is possible to prevent uneven coating during coating, etc. A thermal image forming material having excellent photographic performance can be obtained. On the other hand, if the addition time of the hardener is a time before 30 minutes from the application time, streak failure and application unevenness occur, and the surface condition deteriorates. In addition, the sensitivity tends to decrease, and the fog tends to increase.
[0008]
The thermal image forming material in the present invention is preferably a photothermographic material having a photosensitive emulsion layer containing photosensitive silver halide as a thermal image forming layer. In addition, the thermal image forming layer and the protective layer are coated simultaneously by applying two or more layers at the same time, and then drying the applied layers, rather than by sequential coating in which each layer is coated and dried one by one. It is preferable to form a layer. In addition, although drying may be performed by any known method, a drying method using wind is generally used.
[0009]
The organic silver salt that can be used in the present invention is relatively stable to light, but is 80 ° C. or higher in the presence of an exposed photocatalyst (such as a latent image of photosensitive silver halide) and a reducing agent. It is a silver salt that forms a silver image when heated above. The organic silver salt may be any organic material containing a source capable of reducing silver ions. Silver salts of organic acids, particularly silver salts of long chain fatty carboxylic acids (having 10 to 30, preferably 15 to 28 carbon atoms) are preferred. Preference is also given to organic or inorganic silver salt complexes in which the ligand has a complex stability constant in the range of 4.0 to 10.0. The silver-providing material can preferably constitute about 5 to 70% by weight of the thermal imaging layer. Preferred organic silver salts include silver salts of organic compounds having a carboxyl group. Examples of these include, but are not limited to, silver salts of aliphatic carboxylic acids and silver salts of aromatic carboxylic acids. Preferred examples of the aliphatic carboxylic acid silver salt include silver behenate, silver arachidate, silver stearate, silver oleate, silver laurate, silver caproate, silver myristate, silver palmitate, silver maleate and fumarate. Silver acid, silver tartrate, silver linoleate, silver butyrate and silver camphorate, mixtures thereof, and the like.
[0010]
Silver salts of compounds containing a mercapto group or a thione group and derivatives thereof can also be used. Preferred examples of these compounds include silver salt of 3-mercapto-4-phenyl-1,2,4-triazole, silver salt of 2-mercaptobenzimidazole, silver salt of 2-mercapto-5-aminothiadiazole, 2 Silver salt of thioglycolic acid such as silver salt of-(ethylglycolamide) benzothiazole, silver salt of S-alkylthioglycolic acid (wherein the alkyl group has 12 to 22 carbon atoms), silver salt of dithioacetic acid, etc. Silver salt of dithiocarboxylic acid, silver salt of thioamide, silver salt of 5-carboxyl-1-methyl-2-phenyl-4-thiopyridine, silver salt of mercaptotriazine, silver salt of 2-mercaptobenzoxazole, US Patent No. Silver salts described in US Pat. No. 4,123,274, silver salts of 1,2,4-mercaptothiazole derivatives such as silver salts of 3-amino-5-benzylthio-1,2,4-thiazole, and the like described in US Pat. 3- (3-carboxyethyl) -4- Include silver salts of thione compounds such as silver salt of chill-4-thiazoline-2-thione. Furthermore, a compound containing an imino group can also be used. Preferred examples of these compounds include silver salts of benzotriazole and derivatives thereof, for example, silver salts of benzotriazole such as silver methylbenzotriazole, silver salts of halogen-substituted benzotriazole such as silver 5-chlorobenzotriazole, US Patent 1,2,4-triazole or silver salt of 1-H-tetrazole as described in US Pat. No. 4,220,709, and silver salts of imidazole and imidazole derivatives. For example, various silver acetylide compounds as described in US Pat. Nos. 4,761,361 and 4,775,613 can also be used.
[0011]
Although there is no restriction | limiting in particular as a shape of the organic silver salt which can be used for this invention, The acicular crystal | crystallization which has a short axis and a long axis is preferable. In the present invention, the minor axis is preferably 0.01 μm to 0.20 μm, the major axis is 0.10 μm to 5.0 μm, the minor axis is 0.01 μm to 0.15 μm, and the major axis is 0.10 μm to 4.0 μm. The particle size distribution of the organic silver salt is preferably monodispersed. Monodispersion is preferably 100% or less, more preferably 80% or less, and even more preferably 50% of the value obtained by dividing the standard deviation of the lengths of the short and long axes by the short and long axes, respectively. It is as follows. The method for measuring the shape of the organic silver salt can be determined from a transmission electron microscope image of the organic silver salt dispersion. As another method for measuring monodispersity, there is a method for obtaining the standard deviation of the volume weighted average diameter of the organic silver salt, and the 100 fraction (coefficient of variation) of the value divided by the volume weighted average diameter is preferably 100% or less. More preferably, it is 80% or less, and further preferably 50% or less. As a measuring method, for example, it is obtained from the particle size (volume weighted average diameter) obtained by irradiating an organic silver salt dispersed in a liquid with laser light and obtaining an autocorrelation function with respect to temporal change of fluctuation of the scattered light. Can do.
[0012]
The organic silver salt that can be used in the present invention can be preferably desalted. There is no particular limitation on the method for performing desalting, and a known method can be used, but a known filtration method such as centrifugal filtration, suction filtration, ultrafiltration, and flock-forming water washing by agglomeration method can be preferably used.
[0013]
For the purpose of obtaining fine particles having a small particle size and no aggregation, the organic silver salt that can be used in the present invention is a method of forming a solid fine particle dispersion using a dispersant. The method of dispersing the organic silver salt in the form of solid fine particles is carried out in the presence of a dispersion aid by known finer means (for example, ball mill, vibration ball mill, planetary ball mill, sand mill, colloid mill, jet mill, roller mill, microfluidizer, Nanomizer, Gaurin homogenizer) can be mechanically dispersed, and a microfluidizer, Nanomizer, and Gaurin homogenizer are preferably used.
[0014]
When organic silver salt is made into solid fine particles using a dispersant, for example, polyacrylic acid, acrylic acid copolymer, maleic acid copolymer, maleic acid monoester copolymer, acryloylmethylpropane sulfonic acid Synthetic anionic polymers such as copolymers, semi-synthetic anionic polymers such as carboxymethyl starch and carboxymethyl cellulose, anionic polymers such as alginic acid and pectinic acid, anions described in JP-A-52-92716, WO88 / 04794, etc. Surfactants, compounds described in Japanese Patent Application No. 7-350753, or known anionic, nonionic, cationic surfactants, and other polyvinyl alcohol, polyvinyl pyrrolidone, carboxymethyl cellulose, hydroxypropyl cellulose, hydroxypropyl methylcellulose Known polymers such as Alternatively, a polymer compound existing in nature such as gelatin can be appropriately selected and used.
[0015]
Dispersing aid is generally mixed with organic silver salt powder or wet cake organic silver salt before dispersion, and sent to the disperser as a slurry. It is good also as an organic silver salt powder or a wet cake by heat-treating and the process by a solvent. The pH may be controlled with an appropriate pH adjuster before, during or after dispersion.
[0016]
In addition to mechanical dispersion, it may be coarsely dispersed in a solvent by controlling the pH, and then finely divided by changing the pH in the presence of a dispersion aid. At this time, an organic solvent may be used as a solvent used for the coarse dispersion, and the organic solvent is usually removed after the formation of fine particles.
[0017]
The prepared dispersion is stored with stirring for the purpose of suppressing sedimentation of fine particles during storage, or stored in a highly viscous state (for example, in a gelatinized state using gelatin) with a hydrophilic colloid. You can also In addition, a preservative can be added for the purpose of preventing the propagation of various bacteria during storage.
[0018]
Although the organic silver salt of the present invention can be used in a desired amount, the thermal imaging material 1 m ² Indicated by the amount per unit, 0.1-5g / m as the amount of silver ² Is preferred, more preferably 1 to 3 g / m ² It is.
[0019]
The reducing agent for the organic silver salt of the present invention may be any substance, preferably an organic substance, that reduces silver ions to metallic silver. Conventional photographic developers such as phenidone, hydroquinone and catechol are useful, but hindered phenol reducing agents are preferred. The reducing agent is preferably contained in an amount of 5 to 50% (mole), more preferably 10 to 40% (mole), based on 1 mol of silver on the surface having the thermal image forming layer. The reducing agent may be a so-called precursor that is derivatized so as to have an effective function only during development.
[0020]
In photothermographic materials using organic silver salts, a wide range of reducing agents are disclosed in JP-A-46-6074, 47-1238, 47-33621, 49-46427, 49-115540, 50-14334, 50-36110, 50-147711, 51-32632, 51-1023721, 51-32324, 51-51933, 52-84727, 55- 108654, 56-146133, 57-82828, 57-82829, JP-A-6-3793, U.S. Pat.No. 3,667,9586, 3,679,426, 3,751,252, 3,751,255, 3,761,270 No. 3,782,949, No. 3,839,048, No. 3,928,686, No. 5,464,738, German Patent No. 2321328, European Patent No. 692732, and the like. For example, amide oximes such as phenylamidooxime, 2-thienylamidooxime and p-phenoxyphenylamidooxime; azines such as 4-hydroxy-3,5-dimethoxybenzaldehyde azine; 2,2-bis (hydroxymethyl) propionyl- a combination of an aliphatic carboxylic acid aryl hydrazide such as a combination of β-phenylhydrazine and ascorbic acid and ascorbic acid; a combination of polyhydroxybenzene and hydroxylamine, reductone and / or hydrazine (eg hydroquinone and bis (ethoxyethyl) ) Such as combinations of hydroxylamine, piperidinohexose reductone or formyl-4-methylphenylhydrazine); such as phenylhydroxamic acid, p-hydroxyphenylhydroxamic acid and β-arininhydroxamic acid Hydroxamic acid; Combination of azine and sulfonamidophenol (for example, phenothiazine and 2,6-dichloro-4-benzenesulfonamidophenol); Ethyl-α-cyano-2-methylphenylacetate, ethyl-α-cyanophenylacetate Α-cyanophenylacetic acid derivatives such as: 2,2-dihydroxy-1,1-binaphthyl, 6,6-dibromo-2,2-dihydroxy-1,1-binaphthyl and bis (2-hydroxy-1-naphthyl) methane A combination of bis-β-naphthol and a 1,3-dihydroxybenzene derivative (such as 2,4-dihydroxybenzophenone or 2,4-dihydroxyacetophenone); 5-pyrazolones such as 1-phenyl-5-pyrazolone; dimethylaminohexose reductone, anhydrodihydroaminohexose reductone and Reductones as exemplified by hydrodihydropiperidone hexose reductone; sulfonamide phenol reducing agents such as 2,6-dichloro-4-benzenesulfonamidophenol and 2-phenylindan-1, 3-diones, etc .; 2,2-dimethyl-7-t-butyl-6-hydroxychromans and other chromanes; 2,6-dimethoxy-3,5-dicarboethoxy-1,4-dihydropyridines and other 1,4- Dihydropyridines; bisphenols (eg bis (2-hydroxy-3-t-butyl-5-methylphenyl) methane, 2,2-bis (4-hydroxy-3-methylphenyl) propane, 4,4-ethylidene-bis ( 2-t-butyl-6-methylphenol), 1,1, -bis (2-hydroxy-3,5-dimethylphenyl) -3,5,5-trimethylhexane and 2,2-bis (3,5- Dimethyl-4-hydroxyphenyl) propane, etc.); ascorbic acid Conductors (e.g., palmitate 1-ascorbyl stearate, etc. Ascorbyl); and aldehydes and ketones such as benzyl and biacetyl; 3-pyrazolidones and certain indane-1,3-dione; chromanol (tocopherol), and the like. Particularly preferred reducing agents are bisphenol and chromanol.
[0021]
The reducing agent of the present invention may be added by any method such as a solution, a powder, or a solid fine particle dispersion. The solid fine particle dispersion is performed by a known refinement means (for example, a ball mill, a vibrating ball mill, a sand mill, a colloid mill, a jet mill, a roller mill, a microfluidizer, a nanomizer, and a Gaurin homogenizer). A dispersion aid may be used when dispersing the solid fine particles.
[0022]
At least one of the thermal image-forming layers of the present invention (specifically, a light-sensitive emulsion layer, a heat-sensitive layer, etc.) is a thermal image-forming layer containing at least 50 wt% of the polymer latex described below (hereinafter referred to as this layer). The thermal image forming layer is referred to as “thermal image forming layer of the present invention”, and the polymer latex used for the binder is referred to as “polymer latex of the present invention”). However, the “polymer latex” mentioned here is a water-insoluble hydrophobic polymer dispersed as fine particles in a water-soluble dispersion medium. As the dispersion state, the polymer is emulsified in a dispersion medium, the emulsion is polymerized, the micelle is dispersed, or the polymer molecule has a partially hydrophilic structure and the molecular chain itself is molecularly dispersed. Anything may be used. As for the polymer latex of the present invention, `` synthetic resin emulsion (Hiraku Okuda, Hiroshi Inagaki, published by Kobunshi Publishing (1978)) '', `` Application of synthetic latex (Takaaki Sugimura, Tatsuo Kataoka, Junichi Suzuki, Keiji Kasahara, Published by Polymer Publishing Association (1993)), “chemistry of synthetic latex (written by Soichi Muroi, published by Polymer Publishing Association (1970))”, and the like. The average particle size of the dispersed particles is preferably 1 to 50000 nm, more preferably about 5 to 1000 nm. The particle size distribution of the dispersed particles is not particularly limited, and may have a wide particle size distribution or a monodispersed particle size distribution.
[0023]
The polymer latex of the present invention may be a so-called core / shell type latex other than a normal polymer latex having a uniform structure. In this case, it may be preferable to change the glass transition temperature between the core and the shell.
[0024]
The minimum film forming temperature (MFT) of the polymer latex of the present invention is preferably -30 to 90 ° C, more preferably about 0 to 70 ° C. A film-forming auxiliary may be added to control the minimum film-forming temperature. The film-forming aid is also called a plasticizer and is an organic compound (usually an organic solvent) that lowers the minimum film-forming temperature of polymer latex.For example, the `` Synthetic Latex Chemistry (Souichi Muroi, published by Kobunshi Shuppankai (1970) )"It is described in.
[0025]
Examples of the polymer species used in the polymer latex of the present invention include acrylic resins, vinyl acetate resins, polyester resins, polyurethane resins, rubber resins, vinyl chloride resins, vinylidene chloride resins, polyolefin resins, and copolymers thereof. The polymer may be a linear polymer, a branched polymer, or a crosslinked polymer. The polymer may be a so-called homopolymer obtained by polymerizing a single monomer, or a copolymer obtained by polymerizing two or more monomers. In the case of a copolymer, it may be a random copolymer or a block copolymer. The molecular weight of the polymer is a number average molecular weight of 5,000 to 100,000, preferably about 10,000 to 100,000. When the molecular weight is too small, the thermal strength of the thermal image forming layer is insufficient, and when the molecular weight is too large, the film forming property is poor, which is not preferable.
[0026]
The polymer latex polymer used in the present invention preferably has an equilibrium water content of 2 wt% or less, more preferably 1 wt% or less at 25 ° C. and 60% RH. Although there is no restriction | limiting in particular in the minimum of an equilibrium moisture content, 0.01 wt% is preferable, More preferably, it is 0.03 wt%. For the definition and measurement method of the equilibrium moisture content, for example, “Polymer Engineering Course 14, Polymer Material Testing Method (Edited by Polymer Society, Jinshokan)” can be referred to.
[0027]
Specific examples of the polymer latex used as the binder of the thermal image forming layer of the thermal image forming material of the present invention include the following. Latex of methyl methacrylate / ethyl acrylate / methacrylic acid copolymer, latex of methyl methacrylate / 2 ethylhexyl acrylate / styrene / acrylic acid copolymer, latex of styrene / butadiene / acrylic acid copolymer, latex of styrene / butadiene / divinylbenzene / methacrylic acid copolymer, Methyl methacrylate / vinyl chloride / acrylic acid copolymer latex, vinylidene chloride / ethyl acrylate / acrylonitrile / methacrylic acid copolymer latex, and the like. Moreover, such a polymer is also marketed and the following polymers can be utilized. For example, as an example of an acrylic resin, Sebian A-4635,46583, 4601 (manufactured by Daicel Chemical Industries, Ltd.), Nipol Lx811, 814, 821, 820, 857 (manufactured by Nippon Zeon Co., Ltd.), etc. FINETEX ES650, 611, 675, 850 (Dainippon Ink Chemical Co., Ltd.), WD-size, WMS (Eastman Chemical), and other polyurethane resins are HYDRAN AP10, 20, 30, 40 (or more Rubber resins such as LACSTAR 7310K, 3307B, 4700H, 7132C (manufactured by Dainippon Ink Chemical Co., Ltd.), Nipol Lx416, 410, 438C, 2507, (manufactured by Nippon Zeon Co., Ltd.) Etc.), vinyl chloride resin G351, G576 (made by Nippon Zeon Co., Ltd.), vinylidene chloride resin L502, L513 (made by Asahi Kasei Kogyo Co., Ltd.), etc., olefin resin, Chemipearl S120 , SA100 (Mitsui Petrochemical Co., Ltd.) The These polymers may be used alone or in combination of two or more as required.
[0028]
In the thermal image forming layer of the present invention, the polymer latex is used as 50 wt% or more of the total binder, but the polymer latex is preferably used as 70 wt% or more.
[0029]
If necessary, a hydrophilic polymer such as gelatin, polyvinyl alcohol, methyl cellulose, hydroxypropyl cellulose, carboxymethyl cellulose, or hydroxypropyl methylcellulose may be added to the thermal image forming layer of the present invention within a range of 50 wt% or less of the total binder. . The addition amount of these hydrophilic polymers is preferably 30 wt% or less of the total binder of the thermal image forming layer.
[0030]
The thermal image forming layer of the present invention is preferably prepared by applying an aqueous coating solution and then drying it. However, “aqueous” as used herein means that 30 wt% or more of the solvent (dispersion medium) of the coating solution is water. As components other than water in the coating solution, water-miscible organic solvents such as methyl alcohol, ethyl alcohol, isopropyl alcohol, methyl cellosolve, ethyl cellosolve, dimethylformamide, and ethyl acetate can be used. Specific examples of the solvent composition include the following in addition to water. Water / methanol = 90/10, water / methanol = 70/30, water / ethanol = 90/10, water / isopropanol = 90/10, water / dimethylformamide = 95/5, water / methanol / dimethylformamide = 80 / 15/5, water / methanol / dimethylformamide = 90/5/5. (However, the numbers represent wt%.)
[0031]
The total binder amount of the thermal image forming layer of the present invention is 0.2 to 30 g / m. ² , More preferably 1-15m ² The range of is preferable. In the thermal image forming layer of the present invention, a crosslinking agent for crosslinking, a surfactant for improving coating properties, and the like may be added.
[0032]
The organic silver salt-containing fluid or the thermal image forming layer coating solution in the present invention is preferably a so-called thixotropic fluid. Thixotropy refers to the property that the viscosity decreases as the shear rate increases.
[0033]
Although any apparatus may be used for the viscosity measurement of the present invention, an RFS fluid spectrometer manufactured by Rheometrics Far East Co., Ltd. is preferably used and measured at 25 ° C.
[0034]
In the present invention, the organic silver salt-containing fluid or the thermal image forming layer coating solution has a shear rate of 0.1 s. ^-1 The viscosity in is preferably 400 mPa · s or more and 100,000 mPa · s or less, and more preferably 500 mPa · s or more and 20,000 mPa · s or less. Also, shear rate 1000s ^-1 Is preferably 1 mPa · s or more and 200 mPa · s or less, and more preferably 5 mPa · s or more and 80 mPa · s or less.
[0035]
Various systems that exhibit thixotropic properties are known, and are described in “Lectures / Rheology” edited by Polymer Publishing Co., “Polymer Latex” (published by Polymer Publishing Co., Ltd.) co-authored by Muroi and Morino. In order for the fluid to exhibit thixotropy, it is necessary to contain a large amount of solid fine particles. In order to enhance the thixotropy, it is effective to contain a thickening linear polymer, increase the aspect ratio in the anisotropic shape of the contained solid fine particles, increase the alkali viscosity, and use a surfactant.
[0036]
In the present invention, a photosensitive silver halide is used. The The method for forming photosensitive silver halide in the present invention is well known in the art, and for example, the methods described in Research Disclosure No. 17029 of June 1978 and US Pat. No. 3,700,458 can be used. . Specific methods that can be used in the present invention include a method in which a part of silver of an organic silver salt is converted into photosensitive silver halide by adding a halogen-containing compound to the prepared organic silver salt, gelatin Alternatively, a method of preparing photosensitive silver halide grains by adding a silver supply compound and a halogen supply compound to another polymer solution and mixing it with an organic silver salt can be used. In the present invention, the latter method can be preferably used. The grain size of the photosensitive silver halide is preferably small for the purpose of keeping the white turbidity after image formation low, specifically 0.20 μm or less, more preferably 0.01 μm or more and 0.15 μm or less, and further preferably 0.02 μm or more. 0.12 μm or less is preferable. The grain size here 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 a diameter when converted into a circular image having the same area as the projected area of the main surface. In the case of other non-normal crystals, for example, in the case of spherical grains, rod-shaped grains, etc., it means the diameter when considering a sphere equivalent to the volume of silver halide grains.
[0037]
Examples of the shape of the silver halide grains include cubes, octahedrons, tabular grains, spherical grains, rod-shaped grains, and potato grains. In the present invention, cubic grains and tabular grains are particularly preferred. When tabular silver halide grains are used, the average aspect ratio is preferably 100: 1 to 2: 1, more preferably 50: 1 to 3: 1. Further, grains having rounded corners of silver halide grains can be preferably used. There are no particular restrictions on the surface index (Miller index) of the outer surface of the photosensitive silver halide grains, but the {100} surface occupies a high proportion of spectral sensitization efficiency when the spectral sensitizing dye is adsorbed. preferable. The ratio is preferably 50% or more, more preferably 65% or more, and still more preferably 80% or more. The ratio of Miller index {100} plane is calculated by T.Tani; J.Imaging Sci., 29, 165 (1985) using the adsorption dependence of {111} plane and {100} plane in sensitizing dye adsorption. It can be determined by the method described. The halogen composition of the photosensitive silver halide is not particularly limited and may be any of silver chloride, silver chlorobromide, silver bromide, silver iodobromide, silver iodochlorobromide, and silver iodide. In the present invention, silver bromide or silver iodobromide can be preferably used. Particularly preferred is silver iodobromide, and the silver iodide content is preferably from 0.1 mol% to 40 mol%, more preferably from 0.1 mol% to 20 mol%. The distribution of the halogen composition in the grain may be uniform, the halogen composition may be changed stepwise, or may be continuously changed. High silver iodobromide grains can be used. In addition, silver halide grains preferably having a core / shell structure can be used. As the structure, core / shell particles having a preferably 2- to 5-fold structure, more preferably a 2- to 4-fold structure can be used.
[0038]
The photosensitive silver halide grain of the present invention preferably contains at least one metal complex selected from rhodium, rhenium, ruthenium, osmium, iridium, cobalt, mercury or iron. One kind of these metal complexes may be used, or two or more kinds of complexes of the same metal and different metals may be used in combination. The preferred content is in the range of 1 nmol to 10 mmol, and more preferably in the range of 10 nmol to 100 μmol, with respect to 1 mol of silver. As a specific metal complex structure, a metal complex having a structure described in JP-A-7-225449 can be used. For cobalt and iron compounds, hexacyano metal complexes can be preferably used. Specific examples include, but are not limited to, ferricyanate ions, ferrocyanate ions, hexacyanocobaltate ions, and the like. The metal complex in the silver halide may be contained uniformly, may be contained in the core part at a high concentration, or may be contained in the shell part at a high concentration, and there is no particular limitation.
[0039]
The photosensitive silver halide grains can be desalted by washing with water by a method known in the art such as a noodle method or a flocculation method, but in the present invention, it may or may not be desalted.
[0040]
The photosensitive silver halide grains in the present invention are preferably chemically sensitized. As a preferable chemical sensitization method, a sulfur sensitization method, a selenium sensitization method and a tellurium sensitization method can be used as is well known in the art. Further, noble metal sensitization methods such as gold compounds, platinum, palladium, iridium compounds and reduction sensitization methods can be used. As the compound preferably used in the sulfur sensitization method, selenium sensitization method and tellurium sensitization method, known compounds can be used, but compounds described in JP-A-7-128768 and the like can be used. Examples of tellurium sensitizers include diacyl tellurides, bis (oxycarbonyl) tellurides, bis (carbamoyl) tellurides, diacyl tellurides, bis (oxycarbonyl) ditellurides, bis (carbamoyl) ditellurides, P = Te Compounds having a bond, tellurocarboxylates, Te-organyl tellurocarboxylates, di (poly) tellurides, tellurides, tellurols, telluroacetals, tellurosulfonates, compounds having a P-Te bond, Te heterocycles, tellurocarbonyl compounds, inorganic tellurium compounds, colloidal tellurium and the like can be used. As the compound preferably used in the noble metal sensitization method, for example, chloroauric acid, potassium chloroaurate, potassium aurithiocyanate, gold sulfide, gold selenide, or compounds described in US Pat. No. 2,448,060, British Patent 618,061, etc. are preferable. Can be used. As specific compounds of the reduction sensitization method, for example, stannous chloride, aminoiminomethanesulfinic acid, hydrazine derivatives, borane compounds, silane compounds, polyamine compounds, etc. can be used in addition to ascorbic acid and thiourea dioxide. . Further, reduction sensitization can be performed by ripening the emulsion while maintaining the pH at 7 or higher or pAg at 8.3 or lower. Further, reduction sensitization can be performed by introducing a single addition portion of silver ions during grain formation.
[0041]
The amount of the photosensitive silver halide used in the present invention is preferably 0.01 to 0.5 mol or less, more preferably 0.02 to 0.3 mol, and more preferably 0.03 to 0.25 mol with respect to 1 mol of the organic silver salt. Is particularly preferred. The mixing method and mixing conditions of the photosensitive silver halide prepared separately from the organic silver salt into the thermal image forming layer coating solution are not particularly limited as long as the effects of the present invention are sufficiently exhibited.
[0042]
As the silver halide preparation method of the present invention, a so-called hydration method in which a part of silver of the organic silver salt is halogenated with an organic or inorganic halide is also preferably used. Any organic halide may be used as long as it is a compound that reacts with an organic silver salt to produce silver halide. However, N-halogenoimide (N-bromosuccinimide, etc.), halogenated quaternary nitrogen compound (odor) And tetrabutylammonium bromide), and halogenated quaternary nitrogen salts and halogen molecule associations (pyridinium perbromide). The inorganic halogen compound may be any compound as long as it is a compound that reacts with an organic silver salt to produce silver halide, but alkali metal halide or ammonium (sodium chloride, lithium bromide, potassium iodide, ammonium bromide, etc. ), Alkaline earth metal halides (calcium bromide, magnesium chloride, etc.), transition metal halides (ferric chloride, cupric bromide, etc.), metal complexes with halogen ligands (sodium iridate bromide) , Ammonium rhodate, etc.) and halogen molecules (bromine, chlorine, iodine). Moreover, you may use desired organic inorganic halide together.
[0043]
In the present invention, the amount of halide added during the halide is preferably 1 to 500 mmol, more preferably 10 to 250 mmol as a halogen atom per mol of the organic silver salt.
In the present invention, the silver halide is preferably prepared separately from the organic silver salt for the purpose of obtaining desired good photographic performance.
[0044]
The photosensitive silver halide in the present invention is preferably spectrally sensitized with a sensitizing dye.
[0045]
Any sensitizing dye of the present invention may be used as long as it can spectrally sensitize the silver halide grains in a desired wavelength region when adsorbed on the silver halide grains. As the sensitizing dye, cyanine dyes, merocyanine dyes, complex cyanine dyes, complex merocyanine dyes, holopolar cyanine dyes, styryl dyes, hemicyanine dyes, oxonol dyes, hemioxonol dyes, and the like can be used. Useful sensitizing dyes used in the present invention are described in, for example, the references described or cited in RESEARCH DISCLOSURE Item 17643IV-A (December 1978 p.23), Item1831X (August 1979 p.437) Has been. In particular, a sensitizing dye having a spectral sensitivity suitable for the spectral characteristics of the light sources of various laser imagers, scanners, image setters and plate-making cameras can be advantageously selected.
[0046]
As an example of spectral sensitization to red light, a so-called red light source such as a He-Ne laser, a red semiconductor laser, or an LED is disclosed in Japanese Patent Application Laid-Open No. 54-18726. Compounds, compounds of I-1 to I-35 described in JP-A-6-75322, compounds of I-1 to I-34 described in JP-A-7-287338, dyes described in JP-B-55-39818 1 to 20, compounds of I-1 to I-37 described in JP-A-62-284343 and compounds of I-1 to I-34 described in JP-A-7-287338 are advantageously selected.
[0047]
For semiconductor laser light sources in the 750-1400 nm wavelength range, various known dyes including cyanine, merocyanine, styryl, hemicyanine, oxonol, hemioxonol and xanthene dyes can be spectrally sensitized. it can. Useful cyanine dyes are, for example, cyanine dyes having basic nuclei such as thiazoline nucleus, oxazoline nucleus, pyrroline nucleus, pyridine nucleus, oxazole nucleus, thiazole nucleus, selenazole nucleus and imidazole nucleus. Useful merocyanine dyes are preferably acidic nuclei such as thiohydantoin nucleus, rhodanine nucleus, oxazolidinedione nucleus, thiazolinedione nucleus, barbituric acid nucleus, thiazolinone nucleus, malononitrile nucleus and pyrazolone nucleus in addition to the basic nuclei described above. Including. Of the above-mentioned cyanine and merocyanine dyes, those having an imino group or a carboxyl group are particularly effective. For example, U.S. Pat.Nos. -194781 and 6-301141 may be appropriately selected from known dyes.
[0048]
Particularly preferred as the structure of the dye used in the present invention is a cyanine dye having a thioether bond-containing substituent (for example, JP-A Nos. 62-58239, 3-138638, 3-138642, and 4- No. 255840, No. 5-72659, No. 5-72661, No. 6-222491, No. 2-230506, No. 6-258757, No. 6-317868, No. 6-324425, and No. 7- No. 500926, dyes described in U.S. Pat.No. 5,541,054), dyes having a carboxylic acid group (for example, dyes described in JP-A Nos. 3-163440 and 6-301141, U.S. Pat.No. 5,441,899), merocyanine dyes, Multinuclear merocyanine dyes and polynuclear cyanine dyes (JP-A-47-6329, 49-105524, 51-127719, 52-80829, 54-61517, 59-214846, 60-6750) No. 63-159841, JP-A-6-35109, JP-A-6-59381, JP-A-7-65537, JP-A-7-65537, JP-T 55-50111, British Patent 1,467,638, US Patent 5,281,515 Dyes described in 1).
[0049]
Further, as dyes forming J-band, U.S. Pat.Nos. 5,510,236 and 3,871,887 described in Example 5, JP-A-2-96131 and JP-A-59-48753 are disclosed, which are preferable in the present invention. Can be used.
[0050]
These sensitizing dyes may be used alone or in combination of two or more. A combination of sensitizing dyes is often used for the purpose of supersensitization. Along with the sensitizing dye, the emulsion itself may contain a dye having no spectral sensitizing action or a substance that does not substantially absorb visible light and exhibits supersensitization. Useful sensitizing dyes, combinations of dyes exhibiting supersensitization, and substances exhibiting supersensitization are described in Research Disclosure 176, 17643 (issued December 1978), page 23, Section J, or JP-B 49-25500. No. 43-4933, JP-A-59-19032, 59-192242 and the like.
[0051]
Two or more sensitizing dyes used in the present invention may be used in combination. In order to add sensitizing dyes to silver halide emulsions, they may be dispersed directly in the emulsion, or water, methanol, ethanol, propanol, acetone, methyl cellosolve, 2,2,3,3 -Solvent alone such as tetrafluoropropanol, 2,2,2-trifluoroethanol, 3-methoxy-1-propanol, 3-methoxy-1-butanol, 1-methoxy-2-propanol, N, N-dimethylformamide Alternatively, it may be dissolved in a mixed solvent and added to the emulsion.
[0052]
Further, as disclosed in US Pat. No. 3,469,987, etc., the dye is dissolved in a volatile organic solvent, this solution is dispersed in water or a hydrophilic colloid, and this dispersion is added to the emulsion. Method, as disclosed in Japanese Patent Publication Nos. 44-23389, 44-27555, 57-22091, etc., a dye is dissolved in an acid, and this solution is added to an emulsion, or an acid or a base is added. Add to emulsion as aqueous solution by coexistence, and add aqueous solution or colloidal dispersion in the presence of surfactant as disclosed in US Pat. Nos. 3,822,135, 4,006,025, etc. As disclosed in JP-A-53-102733 and JP-A-58-105141, a method in which a dye is directly dispersed in a hydrophilic colloid, and the dispersion is added to an emulsion. As disclosed in US Pat. Was dissolved, the solution can also be used a method of adding to the emulsion. In addition, ultrasonic waves can be used for dissolution.
[0053]
The time when the sensitizing dye used in the present invention is added to the silver halide emulsion of the present invention may be during any step of emulsion preparation that has been found useful. For example, as disclosed in the specifications of U.S. Pat.Nos. 2,735,766, 3,628,960, 4,183,756, 4,225,666, JP-A-58-184142, 60-196749, etc., a silver halide grain forming step Alternatively, and / or before the desalting, during the desalting step and / or after the desalting and before the start of the chemical ripening, as disclosed in the specification of JP-A-58-113920, etc. The emulsion may be added at any time just before or during the process, after chemical ripening and before the emulsion is coated before the coating. Further, as disclosed in the specifications of US Pat. No. 4,225,666 and Japanese Patent Application Laid-Open No. 58-7629, the same compound can be used alone or in combination with a compound of a different structure, for example, during the particle formation process. It may be added separately during the ripening process or after chemical ripening, divided before or during chemical ripening, or after completion of the process, etc. You may change and add.
[0054]
The amount of the sensitizing dye used in the present invention may be a desired amount in accordance with the performance such as sensitivity and fog, but it is 10 per mol of silver halide in the photosensitive layer as the thermal image forming layer. ^-6 ~ 1 mole is preferred, 10 ^-Four ~Ten ^-1 Mole is more preferred.
[0055]
Inclusion of an additive known as a “toning agent” that improves the image may increase the optical density. The toning agent may also be advantageous in forming a black silver image. The color toning agent is preferably contained in an amount of 0.1 to 50% (mole) per mole of silver, more preferably 0.5 to 20% (mole), on the surface having the thermal image forming layer. The toning agent may be a so-called precursor that is derivatized so as to have an effective function only during development.
[0056]
In photothermographic materials using organic silver salts, a wide range of color toning agents are disclosed in JP-A-46-6077, 47-10282, 49-5019, 49-5020, 49-91215, 49-91215, 50-2524, 50-32927, 50-67132, 50-67641, 50-114217, 51-3223, 51-27923, 52- 14788, 52-99813, 53-1020, 53-76020, 54-156524, 54-156525, 61-183642, JP 4-56848, JP-B 49- No. 10727, No. 54-20333, US Pat. Nos. 3,080,254, 3,446,648, 3,782,941, 4,123,282, 4,510,236, British Patent 1380795, Belgian Patent 841910 and the like. Examples of toning agents are phthalimide and N-hydroxyphthalimide; succinimide, pyrazolin-5-one, and quinazolinone, 3-phenyl-2-pyrazolin-5-one, 1-phenylurazole, quinazoline and 2,4-thiazolidinedione Cyclic imides such as: naphthalimide (eg, N-hydroxy-1,8-naphthalimide); cobalt complex (eg, cobalt hexamine trifluoroacetate); 3-mercapto-1,2,4-triazole, 2,4 Mercaptans, exemplified by 2-dimercaptopyrimidine, 3-mercapto-4,5-diphenyl-1,2,4-triazole and 2,5-dimercapto-1,3,4-thiadiazole; N- (aminomethyl) aryl Dicarboximide (eg, (N, N-dimethylaminomethyl) phthalimide and N, N- (dimethylaminomethyl) -naphthalene-2,3-dicarboximide); Pyrazoles, isothiuronium derivatives and certain photobleaching agents (e.g., N, N'-hexamethylenebis (1-carbamoyl-3,5-dimethylpyrazole), 1,8- (3,6-diazaoctane) bis ( Isothiuronium trifluoroacetate) and 2-tribromomethylsulfonyl)-(benzothiazole)); and 3-ethyl-5 [(3-ethyl-2-benzothiazolinylidene) -1-methylethylidene] -2 -Thio-2,4-oxazolidinedione; phthalazinone, phthalazinone derivatives or metal salts, or 4- (1-naphthyl) phthalazinone, 6-chlorophthalazinone, 5,7-dimethoxyphthalazinone and 2,3-dihydro-1 Derivatives such as 1,4-phthalazinedione; combinations of phthalazinone and phthalic acid derivatives (eg, phthalic acid, 4-methylphthalic acid, 4-nitrophthalic acid, and tetrachlorophthalic anhydride); Gin derivatives or metal salts or derivatives such as 4- (1-naphthyl) phthalazine, 6-chlorophthalazine, 5,7-dimethoxyphthalazine and 2,3-dihydrophthalazine; phthalazine and phthalic acid derivatives (eg phthalates) Acid, 4-methylphthalic acid, 4-nitrophthalic acid and tetrachlorophthalic anhydride, etc.); quinazolinedione, benzoxazine or naphthoxazine derivatives; for in situ silver halide generation as well as color modifiers Rhodium complexes that also function as a source of halide ions, such as ammonium hexachlororhodium (III), rhodium bromide, rhodium nitrate and potassium hexachlororhodium (III); inorganic peroxides and persulfates, such as diperoxide Ammonium sulfide and hydrogen peroxide; 1,3-benzoxazine-2,4-dione, 8-methyl Benzoxazine-2,4-diones such as 1,3-benzoxazine-2,4-dione and 6-nitro-1,3-benzoxazine-2,4-dione; pyrimidines and asymmetric-triazines (eg 2,4-dihydroxypyrimidine, 2-hydroxy-4-aminopyrimidine, etc.), azauracil, and tetraazapentalene derivatives (e.g., 3,6-dimercapto-1,4-diphenyl-1H, 4H-2,3a, 5 , 6a-tetraazapentalene, and 1,4-di (o-chlorophenyl) -3,6-dimercapto-1H, 4H-2,3a, 5,6a-tetraazapentalene).
[0057]
The toning agent of the present invention may be added by any method such as a solution, a powder, or a solid fine particle dispersion. The solid fine particle dispersion is performed by a known finer means (for example, ball mill, vibrating ball mill, sand mill, colloid mill, jet mill, roller mill, etc.). A dispersion aid may be used when dispersing the solid fine particles.
[0058]
The silver halide emulsions and / or organic silver salts in the present invention are further protected against the formation of additional fog by antifoggants, stabilizers and stabilizer precursors, and against reduced sensitivity during inventory storage. Can be stabilized. Suitable antifoggants, stabilizers and stabilizer precursors that can be used alone or in combination are the thiazonium salts described in U.S. Patent Nos. 2,131,038 and 2,694,716, U.S. Patent Nos. 2,886,437 and 2,444,605. Azaindene described in U.S. Pat.No. 2,728,663, mercury salt described in U.S. Pat.No. 3,287,135, sulfocatechol described in U.S. Pat.No. 3,235,652, oxime, nitrone and nitro described in British Patent No. 623,448. Indazole, polyvalent metal salts described in U.S. Pat.No. 2,839,405, thiuonium salts described in U.S. Pat.No. 3,220,839, and palladium, platinum and gold salts described in U.S. Pat.Nos. 2,566,263 and 2,597,915, U.S. Pat. Halogen-substituted organic compounds described in US Pat. Nos. 4,108,665 and 4,442,202, U.S. Pat.Nos. 4,128,557 and 4,137,079, 4,138,365 and And triazine described in U.S. Pat. No. 4,459,350, and phosphorus compounds described in U.S. Pat. No. 4,411,985.
[0059]
Antifoggants preferably used in the present invention are organic halides, such as JP-A-50-119624, 50-120328, 51-121332, 54-58022, 56-70543, 56-99335, 59-90842, 61-129642, 62-129845, JP-A-6-208191, 7-5621, 7-2781, 8-15809, US Examples thereof include compounds disclosed in Japanese Patent Nos. 5340712, 5369000, and 5464737.
[0060]
The antifoggant of the present invention may be added by any method such as a solution, powder or solid fine particle dispersion. The solid fine particle dispersion is performed by a known finer means (for example, ball mill, vibrating ball mill, sand mill, colloid mill, jet mill, roller mill, etc.). A dispersion aid may be used when dispersing the solid fine particles.
[0061]
Although not necessary to practice the present invention, it may be advantageous to add a mercury (II) salt as an antifoggant to the emulsion layer that is the thermal imaging layer. Preferred mercury (II) salts for this purpose are mercury acetate and mercury bromide. The addition amount of mercury used in the present invention is preferably in the range of 1 nmol to 1 mmol, more preferably 10 nmol to 100 μmol, per mol of applied silver.
[0062]
The thermal image forming material in the present invention may contain benzoic acids for the purpose of increasing sensitivity and preventing fogging. The benzoic acid derivatives of the present invention may be any benzoic acid derivative. Examples of preferred structures include U.S. Pat. Nos. 4,784,939, 4,152,160, Japanese Patent Application Nos. 8-512242, 8-151241, and 8-98051. And the compounds described in the above. The benzoic acids of the present invention may be added to any part of the thermal image-forming material, but the additive layer is preferably added to a layer having a thermal image-forming layer such as a photosensitive layer. More preferably, it is added to the containing layer. The benzoic acid of the present invention may be added at any step of preparing the coating solution, and when added to the organic silver salt-containing layer, any step from the preparation of the organic silver salt to the preparation of the coating solution may be used. It is preferable that the salt is prepared and immediately before coating. As a method for adding the benzoic acid of the present invention, any method such as powder, solution, fine particle dispersion and the like may be used. Moreover, you may add as a solution mixed with other additives, such as a sensitizing dye, a reducing agent, and a color toning agent. The addition amount of the benzoic acid of the present invention may be any amount, but it is preferably 1 μmol or more and 2 mol or less, more preferably 1 mmol or more and 0.5 mol or less per 1 mol of silver.
[0063]
In the present invention, a mercapto compound, a disulfide compound, and a thione compound can be contained in order to suppress or promote development and control development, to improve spectral sensitization efficiency, and to improve storage stability before and after development. .
[0064]
When a mercapto compound is used in the present invention, any structure may be used, but those represented by Ar-SM and Ar-SS-Ar are preferred. In the formula, M is a hydrogen atom or an alkali metal atom, and Ar is an aromatic ring group or a condensed aromatic ring group having one or more nitrogen, sulfur, oxygen, selenium or tellurium atoms. Preferably, the heteroaromatic ring in these groups is benzimidazole, naphthoimidazole, benzothiazole, naphthothiazole, benzoxazole, naphthoxazole, benzoselenazole, benzotelrazole, imidazole, oxazole, pyrazole, triazole, thiadiazole, tetrazole, Triazine, pyrimidine, pyridazine, pyrazine, pyridine, purine, quinoline or quinazolinone. The heteroaromatic ring can be, for example, halogen (e.g., Br and Cl), hydroxy, amino, carboxy, alkyl (e.g., having one or more carbon atoms, preferably 1 to 4 carbon atoms) and alkoxy ( For example, it may have one selected from a substituent group consisting of one or more carbon atoms, preferably one having 1 to 4 carbon atoms. Mercapto-substituted heteroaromatic compounds include 2-mercaptobenzimidazole, 2-mercaptobenzoxazole, 2-mercaptobenzothiazole, 2-mercapto-5-methylbenzimidazole, 6-ethoxy-2-mercaptobenzothiazole, 2, 2'-dithiobis-benzothiazole, 3-mercapto-1,2,4-triazole, 4,5-diphenyl-2-imidazolethiol, 2-mercaptoimidazole, 1-ethyl-2-mercaptobenzimidazole, 2-mercaptoquinoline , 8-mercaptopurine, 2-mercapto-4 (3H) -quinazolinone, 7-trifluoromethyl-4-quinolinethiol, 2,3,5,6-tetrachloro-4-pyridinethiol, 4-amino-6- Hydroxy-2-mercaptopyrimidine monohydrate, 2-amino-5-mercapto-1,3,4-thiadiazole, 3-amino-5-mercapto-1,2,4-triazole, 4-hydrido Ci-2-mercaptopyrimidine, 2-mercaptopyrimidine, 4,6-diamino-2-mercaptopyrimidine, 2-mercapto-4-methylpyrimidine hydrochloride, 3-mercapto-5-phenyl-1,2,4-triazole, Examples include 2-mercapto-4-phenyloxazole, but the present invention is not limited to these.
[0065]
The addition amount of these mercapto compounds is preferably in the range of 0.001 to 1.0 mol per mol of silver in the emulsion layer which is a thermal image forming layer, and more preferably 0.01 to 0.3 mol per mol of silver.
[0066]
In the thermal imaging layer in the present invention, polyhydric alcohol (for example, glycerin and diol of the kind described in US Pat. No. 2,960,404) as a plasticizer and lubricant, described in US Pat. Nos. 2,588,765 and 3,121,060 Fatty acids or esters of the above, and silicone resins described in British Patent No. 955,061 can be used.
[0067]
In the present invention, an ultrahigh contrast agent can be used to form an ultrahigh contrast image. For example, U.S. Patent Nos. 5,464,738, 5,496,695, 6,512,411, 5,536,622, Japanese Patent Application Nos. 7-228627, 8-215822, 8-130842, 8-148113, 8 -156378, 8-148111, 8-148116, or a compound having a quaternary nitrogen atom described in Japanese Patent Application No. 8-83566 or U.S. Pat.No. 5,545,515 These acrylonitrile compounds can be used. Specific examples of the compound include compounds 1 to 10 of the aforementioned US Pat. No. 5,464,738, H-1 to H-28 of 5,496,695, I-1 to I-86 of Japanese Patent Application No. 8-215822, and 8- 130842 H-1 to H-62, 8-148113 1-1 to 1-21, 8-148111 1-50, 8-148116 1-40, 8-83566 P-1 to P-26 and T-1 to T-18, CN-1 to CN-13 of US Pat. No. 5,545,515, and the like.
[0068]
Further, in the present invention, in order to form a super high contrast image, a high contrast accelerator can be used in combination with the super high contrast agent. For example, amine compounds described in U.S. Pat.No. 5,545,505, specifically, AM-1 to AM-5, hydroxamic acids described in 5,545,507, specifically HA-1 to HA-11, and 5,545,507 Described acrylonitriles, specifically CN-1 to CN-13, hydrazine compounds described in US Pat. No. 5,558,983, specifically CA-1 to CA-6, described in Japanese Patent Application No. 8-132836 Onum salts, specifically A-1 to A-42, B-1 to B-27, C-1 to C-14, and the like can be used.
[0069]
The synthesis method, the addition method, the addition amount, and the like of these super-high contrast agents and high-contrast accelerators can be performed as described in the respective cited patents.
[0070]
The thermal image forming material in the present invention needs to be provided with a protective layer for the purpose of preventing adhesion of the thermal image forming layer. These protective layers are located on the side farther from the thermal image forming layer with respect to the support, and may be composed of two or more layers.
[0071]
The binder for the surface protective layer of the present invention may be any hydrophilic polymer (hydrophilic colloid), but the polymer having a carboxylic acid residue is 100 mg / m. ² More than 5g / m ² It is preferable to include the following. Examples of the polymer having a carboxyl residue include natural polymers (gelatin, alginic acid, etc.), modified natural polymers (carboxymethylcellulose, phthalated gelatin, etc.), synthetic polymers (polymethacrylate, polyacrylate, polyalkylmethacrylate / acrylate). Copolymer, polystyrene / polymethacrylate copolymer, etc.). The carboxy residue content of such a polymer is preferably 10 mmol or more and 1.4 mol or less per 100 g of the polymer. In addition, the carboxylic acid residue may form a salt with an alkali metal ion, an alkaline earth metal ion, an organic cation or the like.
[0072]
In at least one of the protective layers of the present invention, 50 wt% or more of the binder is preferably gelatin, and 50 wt% or more of the binder of the outermost surface layer is particularly preferably gelatin.
[0073]
As the binder for the protective layer, a polymer having a vinyl alcohol unit is also preferably used (for example, polyvinyl alcohol, polyvinyl alcohol terminally alkylated using an alkyl sulfide as a chain transfer agent).
[0074]
Any adhesion preventing material may be used as the protective layer of the present invention. Examples of anti-adhesive materials include wax, silica particles, styrene-containing elastomeric block copolymers (e.g., styrene-butadiene-styrene, styrene-isoprene-styrene), cellulose acetate, cellulose acetate butyrate, cellulose propionate, and these There is a mixture. Moreover, you may add surfactant etc. for coating property improvement.
[0075]
A hardening agent is used for the protective layer of the present invention. Without the hardener, the water resistance is lost, and stickiness and dissolution due to water droplets occur, which significantly impairs handling as a thermal image forming material.
[0076]
Examples of the hardener of the present invention include each method described on pages 77 to 87 by THJames "THE THEORY OF THE PHOTOGRAPHICPROCESS FOURTH EDITION (Macmillan Publishing Co., Inc., published in 1977)", page 78, etc. Preferred are polyvalent metal ions, polyisocyanates such as US Pat. No. 4,281,060, JP-A-6-208193, epoxy compounds such as US Pat. No. 4,791,042, and vinyl sulfone compounds such as JP-A 62-89048. Particularly preferably, polyvalent metal ions such as chromium ions and aluminum ions are used. In the present invention, at least a compound selected from polyvalent metal ions is used as the hardener. The amount used may be any amount as long as the desired purpose is achieved, but is preferably 1 μmol or more and 1 mmol or less per 1 g of gelatin with respect to the total amount of gelatin on the side having the thermal image forming layer of the support, More preferably, it is more than mol and less than 200 μmol. Boric acid or the like is used as a hardener for polyvinyl alcohol when polyvinyl alcohol is used as the binder.
[0077]
The hardener is added as a solution, and the timing of adding such a solution to the protective layer coating solution is applied. 10 Although it is necessary to add from one minute before, preferably from ten minutes to ten seconds before, the mixing method and mixing conditions are not particularly limited as long as the effects of the present invention are sufficiently exhibited. Specific mixing methods include mixing in a tank in which the average residence time calculated from the addition flow rate and the amount of liquid delivered to the coater is the desired time, and by N. Harnby, MFEdwards, AWNienow, and translation by Koji Takahashi There is a method of using a static mixer described in Chapter 8 of “Liquid Mixing Technology” (published by Nikkan Kogyo Shimbun, 1989).
[0078]
In FIG. 1, the hardener and the pre-hardener addition liquid containing a protective layer coating liquid component other than the hardener are respectively stored in a stirring tank and mixed to prepare the protective layer coating liquid. A schematic diagram of a protective layer coating solution mixing stirrer that is prepared and fed this coating solution to the coater is shown. In such a mixing stirrer, the liquid in the agitation tank is regulated to be kept at a desired temperature (preferably controlled within ± 5 ° C.) by appropriate means, and the liquid level in the agitation tank The flow rate of the hardener and the pre-hardener addition liquid and the amount of the coating liquid fed are regulated so as to maintain a certain level. The desired temperature is a temperature at which the viscosity does not increase in the stirring tank. For example, when gelatin is used as a binder, the temperature is about 30 to 50 ° C. Taking the mixing stirrer as an example, the addition time of the hardener will be described. The total time of the average residence time of the hardener in the stirring tank and the liquid feeding time from the stirring tank to the coater is hard. This is the time from the addition of the film agent to the coating, and this is the predetermined range. In other mixing methods, a desired time can be set according to this.
[0079]
In the present invention, the thermal image-forming layer or the protective layer of the thermal image-forming layer includes a light-absorbing substance and a filter as described in US Pat. Nos. 3,253,921, 2,274,782, 2,527,583, and 2,956,879. Dyes can be used. For example, a dye can be mordanted as described in US Pat. No. 3,282,699. The amount of filter dye used is preferably an absorbance at an exposure wavelength of 0.1 to 3, particularly preferably 0.2 to 1.5.
[0080]
The thermal imaging layer or the protective layer of the thermal imaging layer in the present invention includes a matting agent such as starch, titanium dioxide, zinc oxide, silica, beads of the type described in US Pat. Nos. 2,992,101 and 2,701,245. Polymer beads containing can be contained. The emulsion surface may have any matte degree as long as no stardust failure occurs, but the Beck smoothness is preferably 200 seconds to 10,000 seconds, and more preferably 300 seconds to 10,000 seconds.
[0081]
The heat-developable photographic emulsion of the present invention is a constituent component of one or more layers on a support. One layer composition must contain organic silver salts, silver halides, developers and binders, and optional additional materials such as toning agents, coating aids and other aids. The two-layer configuration must contain an organic silver salt and silver halide in the first emulsion layer (usually the layer adjacent to the support) and some other components in the second or both layers. Don't be. However, a two-layer configuration comprising a single emulsion layer containing all components and a protective topcoat is also conceivable. The construction of a multicolor photosensitive photothermographic material may include a combination of these two layers for each color and includes all components in a single layer as described in US Pat. No. 4,708,928. Also good. In the case of multi-dye multicolor photothermographic materials, each emulsion layer is generally functional or non-functional between each emulsion layer (photosensitive layer) as described in US Pat. No. 4,460,681. By using different barrier layers, they are distinguished from each other and held.
[0082]
Various dyes and pigments can be used in the photosensitive layer, which is the thermal image forming layer of the present invention, from the viewpoint of improving the color tone and preventing irradiation. Any dyes and pigments may be used for the photosensitive layer of the present invention, for example, there are pigments and dyes described in the color index, specifically pyrazoloazole dyes, anthraquinone dyes, azo dyes, azomethine dyes, oxonol dyes, Examples thereof include carbocyanine dyes, styryl dyes, triphenylmethane dyes, indoaniline dyes, indophenol dyes, organic pigments such as phthalocyanine, and inorganic pigments. Preferred dyes used in the present invention include anthraquinone dyes (for example, compounds 1 to 9 described in JP-A-5-341441, compounds 3-6 to 18 and 3-23 to 38 described in JP-A-5-165147), azomethine Dyes (such as compounds 17 to 47 described in JP-A-5-341441), indoaniline dyes (for example, compounds 11 to 19 described in JP-A-5-289227, compounds 47 described in JP-A-5-341441, JP-A-5-341) And compounds 2-10 to 11 described in JP-A No. 165147) and azo dyes (compounds 10 to 16 described in JP-A-5-341441). As a method for adding these dyes, any method such as a solution, an emulsion, a solid fine particle dispersion, or a state mordanted in a polymer mordant may be used. The amount of these compounds used is determined by the desired amount of absorption, but generally 1m ² It is preferably used in the range of 1 μg or more and 1 g or less.
[0083]
In the present invention, the antihalation layer can be provided on the side far from the light source with respect to the photosensitive layer. The antihalation layer preferably has a maximum absorption in a desired wavelength range of 0.3 or more and 2 or less, more preferably an absorption of an exposure wavelength of 0.5 or more and 2 or less, and an absorption in the visible region after processing of 0.001 or more It is preferably less than 0.5, more preferably a layer having an optical density of 0.001 or more and less than 0.3.
[0084]
When antihalation dyes are used in the present invention, such dyes have the desired absorption in the wavelength range, and have a sufficiently low absorption in the visible region after processing, so that any desired absorbance spectrum shape of the antihalation layer can be obtained. It may be a compound. For example, the following is disclosed, but the present invention is not limited to this. As a single dye, JP-A-59-56458, JP-A-2-216140, JP-A-7-13295, JP-A-111432, U.S. Pat.No. 5,380,635, JP-A-2-68539, page 13, lower left column From line 1 to page 14, lower left column, line 9, line 3-24539, page 14, lower left column to page 16, lower right column, the compounds described in Japanese Patent Application Laid-Open No. 52-139136, 53-132334, 56-501480, 57-16060, 57-68831, 57-101835, 59-182436, JP-A-7-36145, 7 -199409, JP-B-48-33692, JP-B-50-16648, JP-B-2-41734, US Patents 4,088,497, 4,283,487, 4,548,896, and 5,187,049.
[0085]
The thermal image forming material in the present invention has a thermal image forming layer such as a photosensitive layer containing at least one silver halide emulsion on one side of the support, and a so-called back layer on the other side. A single-sided thermal imaging material is preferred.
[0086]
In the present invention, a matting agent may be added to improve transportability. The matting agent is generally fine particles of an organic or inorganic compound that is insoluble in water. Any matting agent can be used.For example, the organic matting agents described in U.S. Pat.Nos. 1,939,213, 2,701,245, 2,322,037, 3,262,782, 3,539,344, 3,767,448, etc. Those well known in the art such as the inorganic matting agents described in the respective specifications such as 1,260,772, 2,192,241, 3,257,206, 3,370,951, 3,523,022, and 3,769,020 can be used. For example, specific examples of organic compounds that can be used as matting agents include water-dispersible vinyl polymers such as polymethyl acrylate, polymethyl methacrylate, polyacrylonitrile, acrylonitrile-α-methylstyrene copolymer, polystyrene. , Styrene-divinylbenzene copolymer, polyvinyl acetate, polyethylene carbonate, polytetrafluoroethylene, etc. Examples of cellulose derivatives include methylcellulose, cellulose acetate, cellulose acetate propionate, etc. Examples of starch derivatives include carboxy starch, carboxynitrophenyl Preferably used for starch, urea-formaldehyde-starch reactants, gelatin hardened with known hardeners and hardened gelatin into cocapsulated hardened microcapsules Can be. As examples of the inorganic compound, silicon dioxide, titanium dioxide, magnesium dioxide, aluminum oxide, barium sulfate, calcium carbonate, silver chloride desensitized by a known method, silver bromide, glass, diatomaceous earth and the like can be preferably used. The above matting agents can be used by mixing different kinds of substances as required. The size and shape of the matting agent are not particularly limited, and those having an arbitrary particle size can be used. In the practice of the present invention, it is preferable to use one having a particle size of 0.1 μm to 30 μm. Further, the particle size distribution of the matting agent may be narrow or wide. On the other hand, since the matting agent greatly affects the haze and surface gloss of the coating film, the particle size, shape, and particle size distribution can be brought into a state as needed during preparation of the matting agent or by mixing a plurality of matting agents. preferable.
[0087]
In the present invention, the matte degree of the back layer is preferably a Beck smoothness of 250 seconds or less and 10 seconds or more, and more preferably 180 seconds or less and 50 seconds or more.
[0088]
In the present invention, the matting agent is preferably contained in the outermost surface layer, the layer functioning as the outermost surface layer of the thermal image forming material, or a layer close to the outer surface, and also contained in a layer acting as a so-called protective layer. It is preferred that
[0089]
In the present invention, a suitable binder for the back layer is transparent or translucent and generally colorless, and is a natural polymer synthetic resin, polymer and copolymer, or other media for forming a film such as gelatin, gum arabic, poly (vinyl alcohol), Hydroxyethyl cellulose, cellulose acetate, cellulose acetate butyrate, poly (vinyl pyrrolidone), casein, starch, poly (acrylic acid), poly (methyl methacrylic acid), poly (vinyl chloride), poly (methacrylic acid), copoly (styrene- Maleic anhydride), copoly (styrene-acrylonitrile), copoly (styrene-butadiene), poly (vinyl acetal) s (e.g., poly (vinyl formal) and poly (vinyl butyral)), poly (esters), poly (urethanes) ), Phenoxy resin, poly (vinylidene chloride) Poly (epoxides), poly (carbonates), poly (vinyl acetate), cellulose esters, and polyamides. The binder may be formed from water or an organic solvent or an emulsion.
[0090]
In the present invention, the back layer preferably has a maximum absorption of 0.3 or more and 2 or less in a desired wavelength range, more preferably 0.5 or more and 2 or less, and an absorption in the visible region after processing of 0.001 or more. It is preferably less than 0.5, more preferably a layer having an optical density of 0.001 or more and less than 0.3. Examples of the antihalation dye used for the back layer are the same as those of the antihalation layer described above.
[0091]
Backside resistive heating layers such as those shown in U.S. Pat. Nos. 4,460,681 and 4,374,921 can also be used in photosensitive photothermographic image systems.
[0092]
A hardening agent may be used for each layer other than the protective layer of the thermal image forming layer, such as a thermal image forming layer such as the photosensitive layer of the present invention, a back layer, and the like. Examples of hardeners are THJames' “THE THEORY OF THE PHOTOGRAPHIC PROCESS FOURTH EDITION” (published by Macmillan Publishing Co., Inc., published in 1977), each of the methods described on pages 77 to 87. Polyvalent metal ions, polyisocyanates such as US Pat. No. 4,281,060 and JP-A-6-208193, epoxy compounds such as US Pat. No. 4,791,042, and vinyl sulfone compounds such as JP-A 62-89048 are preferably used. .
[0093]
In the present invention, a surfactant may be used for the purpose of improving coating properties and charging. As an example of the surfactant, any nonionic, anionic, cationic, or fluorine-based one can be used as appropriate. Specifically, fluorine-based polymer surfactants described in JP-A-62-170950, US Pat. No. 5,380,644, etc., fluorine-based surfactants described in JP-A-60-244945, JP-A-63-188135, etc. Surfactants, polysiloxy acid surfactants described in U.S. Pat. No. 3,885,965, polyalkylene oxides and anionic surfactants described in JP-A-6-301140 and the like can be mentioned.
[0094]
Examples of the solvent used in the present invention include New Edition Solvent Pocket Book (Ohm, published in 1994), but the present invention is not limited thereto. The boiling point of the solvent used in the present invention is preferably 40 ° C. or higher and 180 ° C. or lower.
[0095]
Examples of the solvent of the present invention include hexane, cyclohexane, toluene, methanol, ethanol, isopropanol, acetone, methyl ethyl ketone, ethyl acetate, 1,1,1-trichloroethane, tetrahydrofuran, triethylamine, thiophene, trifluoroethanol, perfluoropentane, xylene. , N-butanol, phenol, methyl isobutyl ketone, cyclohexanone, butyl acetate, diethyl carbonate, chlorobenzene, dibutyl ether, anisole, ethylene glycol diethyl ether, N, N-dimethylformamide, morpholine, propane sultone, perfluorotributylamine, water, etc. Is mentioned.
[0096]
The photographic emulsion for heat development in the present invention can be coated on various supports. Typical supports are polyester film, primed polyester film, poly (ethylene terephthalate) film, polyethylene naphthalate film, cellulose nitrate film, cellulose ester film, poly (vinyl acetal) film, polycarbonate film and related or resinous Including materials, as well as glass, paper, metal and the like. Coated with flexible substrates, especially baryta paper, partially acetylated α-olefin polymers, especially polymers of 2-10 carbon atoms such as polyethylene, polypropylene, ethylene-butene copolymers. A paper support is typically used. The support may be transparent or opaque, but is preferably transparent.
[0097]
The thermal imaging materials of the present invention may comprise antistatic or conductive layers such as soluble salts (eg chlorides, nitrates, etc.), vapor deposited metal layers, ionic as described in US Pat. Nos. 2,861,056 and 3,206,312. It may have a layer containing a polymer or an insoluble inorganic salt as described in US Pat. No. 3,428,451.
[0098]
As a method for obtaining a color image using the thermal image forming material in the present invention, there is a method described in JP-A-7-13295, page 10, left column, line 43 to 11, left column, line 40. Examples of color dye image stabilizers include British Patent 1,326,889, U.S. Patent 3,432,300, 3,698,909, 3,574,627, 3,573,050, 3,764,337, and 4,042,394. Yes.
[0099]
The thermal image forming material in the present invention may be applied by any method. Specifically, various coating operations are used, including extrusion coating, slide coating, curtain coating, dip coating, knife coating, flow coating, or extrusion coating using a hopper of the type described in U.S. Pat. Stephen F. Kistler, Petert M. Schweizer “LIQUID FILM COATING” (CHAPMAN & HALL, 1997) pages 399 to 536, preferably used for extrusion coating or slide coating, particularly preferably used for slide coating It is done. An example of the shape of the slide coater used for slide coating is shown in Figure 11b.1 on page 427 of the same book. If desired, two or more layers can be simultaneously coated by the method described in pages 399 to 536 of the same document, the method described in US Pat. No. 2,761,791 and British Patent No. 837,095.
[0100]
Additional layers in the thermal imaging material of the present invention, such as a dye receiving layer for receiving a moving dye image, an opacifying layer when reflective printing is desired, a protective topcoat layer, and a primer known in the photothermographic art Layers can be included. It is preferable that the thermal image forming material of the present invention can form an image with only one material, and it is preferable that a functional layer necessary for image formation such as an image receiving layer does not become another material.
[0101]
The photothermographic material which is a preferred embodiment of the thermal image forming material of the present invention may be developed by any method, but is usually developed by raising the temperature of the photosensitive material exposed imagewise. The preferred development temperature is 80 to 250 ° C, more preferably 100 to 140 ° C. The development time is preferably 1 to 180 seconds, and more preferably 10 to 90 seconds.
[0102]
The photosensitive material which is a preferred embodiment of the present invention may be exposed by any method, but a laser beam is preferable as the exposure light source. As the laser beam according to the present invention, a gas laser, a YAG laser, a dye laser, a semiconductor laser and the like are preferable. A semiconductor laser and a second harmonic generation element can also be used.
[0103]
The light-sensitive material which is a preferred embodiment of the present invention has a low haze upon exposure and tends to generate interference fringes. As this interference fringe generation prevention technique, a laser beam disclosed in Japanese Patent Laid-Open No. 5-11548 etc. is incident obliquely on the photosensitive material, and a multimode laser disclosed in WO95 / 31754 There are known methods of using these, and it is preferable to use these techniques.
[0104]
In order to expose a photosensitive material which is a preferred embodiment of the present invention, laser light is used as disclosed in SPIE vol. 169 Laser Printing, pages 116-128 (1979), JP-A-4-51043, WO95 / 31754, etc. It is preferable that the exposure is performed so as to overlap so that the scanning lines cannot be seen.
[0105]
【Example】
Hereinafter, the present invention will be specifically described by way of examples.
Example 1 << organic Silver salt Preparation of dispersions >>
7 g of stearic acid, 4 g of arachidic acid, 36 g of behenic acid and 850 ml of distilled water were stirred at 90 ° C. while adding 187 ml of 1N-NaOH aqueous solution and reacted for 120 minutes. After adding 65 ml of 1N-nitric acid, the temperature was lowered to 50 ° C. . Next, 125 ml of an aqueous solution of 21 g of silver nitrate was added over 100 seconds while stirring more vigorously, and left as it was for 20 minutes. Thereafter, the solid content was separated by suction filtration, and the solid content was washed with water until the filtrate had a conductivity of 30 μS / cm. After adding 100 g of PVA205 (Kuraray Co., Ltd. polyvinyl alcohol) 10 wt% aqueous solution to the solid content thus obtained, and further adding water to a total weight of 270 g, it is dispersed and organically dispersed in an automatic mortar Silver salt A dispersion was obtained. This organic Silver salt Dispersion using Nanomizer (Nanomizer Co., Ltd.) ^Three Dispersed in organic Silver salt A dispersion was obtained. Organic obtained in this way Silver salt Organic in dispersion Silver salt The particles were needle-like particles having an average minor axis of 0.04 μm, an average major axis of 0.8 μm, and a coefficient of variation of 30%.
[0106]
<< Preparation of reducing agent dispersion >>
To 100 g of 1,1-bis (2-hydroxy-3,5-dimethylphenyl) -3,5,5-trimethylhexane and 50 g of hydroxypropylcellulose, 850 g of water was added and mixed well to obtain a slurry. 840 g of zirconia beads having an average diameter of 0.5 mm were prepared, put into a vessel together with the slurry, and dispersed for 5 hours with a disperser (1/4 G sand grinder mill: manufactured by IMEX Co., Ltd.) to obtain a reducing agent dispersion.
[0107]
<< Preparation of organic polyhalide dispersion >>
940 g of water was added to 50 g of tribromomethylphenylsulfone and 10 g of hydroxypropylcellulose, and mixed well to obtain a slurry. 840 g of zirconia beads having an average diameter of 0.5 mm were prepared, placed in a vessel together with the slurry, and dispersed for 5 hours with a disperser (1/4 G sand grinder mill: manufactured by IMEX Co., Ltd.) to obtain an organic polyhalide dispersion. .
[0108]
<< Preparation of silver halide grains >>
Dissolve 22 g of phthalated gelatin and 30 mg of potassium bromide in 700 ml of water, adjust the pH to 5.0 at a temperature of 35 ° C., and then add 159 ml of an aqueous solution containing 18.6 g of silver nitrate and 0.9 g of ammonium nitrate and 92 ml of potassium bromide and potassium iodide. An aqueous solution containing a molar ratio of: 8 was added over 10 minutes by the control double jet method while maintaining pAg of 7.7. Next, 476 ml of an aqueous solution containing 55.4 g of silver nitrate and 2 g of ammonium nitrate and an aqueous solution pAg7.7 containing 10 μmol / liter of dipotassium hexachloroiridate and 1 mol / liter of potassium bromide for 30 minutes by the control double jet method. After that, 1 g of 4-hydroxy-6-methyl-1,3,3a, 7-tetrazaindene was added, and the pH was further lowered to cause aggregation and sedimentation, followed by desalting. Thereafter, 0.1 g of phenoxyethanol was added to adjust the pH to 5.9 and pAg 8.2 to prepare silver iodobromide grains (iodine content core 8 mol%, average 2 mol%, average size 0.05 μm, projected area variation coefficient 8%, (100 ) Preparation of cubic particles) with an area ratio of 85%.
[0109]
The silver halide grains thus obtained were heated to 60 ° C. and 85 μmol of sodium thiosulfate and 11 μmol, 15 μmol of 2,3,4,5,6-pentafluorophenyldiphenylphosphine selenide per mol of silver. Tellurium compound, 3 μmol of chloroauric acid and 270 μmol of thiocyanic acid were added, and after aging for 120 minutes, rapidly cooled to 40 ° C., and then added with 100 μmol of dye and 500 μmol of 2-mercapto-5-methylbenzimidazole. A silver halide emulsion was obtained by rapid cooling to 0 ° C.
[0110]
<Preparation of emulsion layer coating solution>
Organic Silver salt 1350 g of dispersion, 140 cc of 20 wt% aqueous solution of PVA205, 37 cc of 10 wt% aqueous solution of phthalazine, 220 g of reducing agent dispersion, 61 g of the above organic polyhalide dispersion, LACSTAR 3307B (manufactured by Dainippon Ink & Chemicals, Inc.) SBR latex containing styrene-butadiene copolymer: average particle diameter of dispersed particles 0.1 to 0.15 μm, equilibrium water content of polymer 0.6% by weight at 25 ° C. and 60% RH) 1100 g, halogenated An emulsion layer coating solution was prepared by mixing 120 g of silver emulsion.
[0111]
<Preparation of emulsion surface intermediate layer coating solution>
100 g of MP203 (modified polyvinyl alcohol manufactured by Kuraray Co., Ltd.) was dissolved in 900 cc of water, and further 2 cc of a 5 wt% aqueous solution of di (2-ethylhexyl) sulfosuccinate sodium salt was added.
[0112]
<Preparation of emulsion surface protective layer 1 coating solution>
Dissolve 145 g of inert gelatin in 1110 cc of warm water, 400 g of 20 wt% polyethyl acrylate latex, 57 cc of 1N-sulfuric acid, 10 cc of 5 wt% aqueous sodium salt of di (2-ethylhexyl) sulfosuccinate, 10 wt% methanol of phthalic acid 280 cc of a solution was added to obtain a protective layer coating solution.
[0113]
<< Preparation of emulsion surface protective layer 2 coating solution p >>
130g gelatin dispersion containing 12wt% polymethyl methacrylate fine particles (average particle size size 2.5μm) in 129g inert gelatin dissolved in 1650cc warm water, 65cc 1N-sulfuric acid, di (2-ethylhexyl) sulfosuccinate A protective layer 2 coating solution p was prepared by adding 20 cc of a 5 wt% aqueous solution of sodium salt.
[0114]
<Back layer coating solution>
The solid base N, N, N ', N'-tetraethylguanidine and 4-carboxysulfonyl-phenylsulfone molar ratio 10g salt 10g polyvinyl alcohol 10g, water 88g and 1 / 16G sand grinder mill (IMEX ( To obtain a base solution.
[0115]
An organic solvent phase in which 2.1 g of basic dye precursor, 7.9 g of acidic substance, 0.1 g of dye and 10 g of ethyl acetate are mixed and dissolved is mixed in an aqueous phase consisting of 10 g of polyvinyl alcohol and 80 g of water, and emulsified and dispersed at room temperature. (Average particle size 2.5 μm) was obtained.
[0116]
The back surface coating solution was obtained by mixing 39 g of the base solution thus obtained, 26 g of the dye solution, and 36 g of a 10 wt% polyvinyl alcohol aqueous solution.
[0117]
<Back surface protective layer coating solution>
Gelatin 20g, polymethylmethacrylate (average particle size 7μm) 0.6g, sodium dodecylbenzenesulfonate 0.4g, X-22-2809 (Shin-Etsu Silicone Co., Ltd. silicone compound) 1g was dissolved in 480g of water and a back surface protective layer was applied. A liquid was obtained.
[0118]
<Preparation of thermal image forming material>
SBR and gelatin-coated 175 μm polyethylene terephthalate support back layer coating solution at a flow rate of 647 nm optical density 0.7, back surface protective layer coating solution 50 g / m ² At the same time as coating the same coater as Figure 11b.1 on page 427 of “LIQUID FILM COATING” (CHAPMAN & HALL, 1997) by Stephen F. Kistler and Petert M. Schweizer Emulsion layer coating solution from the support side 82cc / m ² Intermediate layer coating solution 6.5cc / m ² , Protective layer 1 coating solution 12.5cc / m ² 、 Protective layer 2 coating solution P12cc / m ² (Protective layer 2 coating solution p9cc / m ² 3 cc / m of 2 wt% aqueous solution of potassium chromium (III) sulfate 12 hydrate ² Were mixed by the following method), passed through a chilled zone at 10 ° C. (dew point of 0 ° C. or less), and then dried at 30 ° C. and 40% RH wind speed of 20 m / sec.
[0119]
Mixing of protective layer 2 coating solution p before hardening agent addition and 2wt% aqueous solution (hardening agent) of potassium chromium (III) sulfate 12 hydrate is carried out continuously as shown in Fig. 1 and protective layer 2 is applied. The sum of the addition rate of the liquid p and the hardening agent was made equal to the amount per unit time fed to the coater. The time until coating is the sum of the average residence time in the stirring tank (= the amount of liquid stored in the stirring tank / the amount of liquid delivered to the coater) and the residence time in the pipe from the stirring tank to the coater. The amount of the accumulated liquid was changed so that the hardening agent addition to coating time was as shown in Table 1. The liquid temperature in the stirring tank was kept at 40 ° C.
[0120]
The smoothness of the photosensitive material, which is the thermal image forming material thus obtained (the Beck smoothness was investigated using the Oken type smoothness measurement described in J. TAPPI Paper Pulp Test Method No. 5) was 600 seconds on the emulsion surface, The surface was 85 seconds.
The structural formulas of the compounds used above are as shown below.
[0121]
[Chemical 1]

[0122]
(Surface evaluation)
The surface shape of the obtained coated product was evaluated in the state of coating unevenness indicated by the ratio of the number of streaks generated per 10 cm of coating width and the maximum and minimum values of the silver amount (weight) of the coated product. The smaller the number of streaks and the closer the silver amount ratio is to 1.0, the better the surface shape.
[0123]
(Evaluation of photographic performance)
After exposing the photosensitive material at an inclination of 30 degrees with respect to the normal line with a 647 nm Kr laser sensitometer (maximum output 500 mW), the photosensitive material was processed (developed) at 120 ° C for 15 seconds, and the resulting image was evaluated for density The total was done. The measurement results were evaluated by fog (Dmin) and sensitivity (the reciprocal of the ratio of exposure amount giving a density 1.0 higher than Dmin). Regarding the sensitivity, the sensitivity of the photosensitive material 3 was set to 100.
[0124]
The results are shown in Table 1. It can be seen that both planar and photographic performance are good in the region of the present invention. Similarly to the photographic performance evaluation, 0.1 cc of water was dropped on the developed photosensitive material, and when the water resistance was evaluated by wiping after 10 seconds, all the photosensitive materials showed good water resistance. There was no water mark.
[0125]
[Table 1]

[0126]
Example 2
In the preparation of the coating solution P for the protective layer 2 of the photosensitive material 5 of Example 1, a hardener was added and mixed under the same conditions as the photosensitive material 5 using a static mixer to prepare a photosensitive material. When evaluated in the same manner, the same surface condition and photographic performance as those of the photosensitive material 5 of Example 1 were shown.
[0127]
Example 3
A coating amount of 1 mg / m of N- (2-methoxyphenyl) -N-formylhydrazine was applied to the emulsion layer coating solution of the light-sensitive material 5 of Example 1. ² A light-sensitive material was prepared in the same manner except for the above, and evaluated in the same manner as in Example 1. As a result, a good surface condition and photographic performance were exhibited.
[0128]
Example 4
In the light-sensitive material 5 of Example 1, silver halide in the emulsion layer coating solution was not added, but equimolar methyl 3,4-dihydroxybenzoate was added as an aqueous solution instead of the reducing agent dispersion, and the back surface A material to which neither a base solution nor a dye solution was added was used as a heat sensitive material. The heat-sensitive material thus obtained was heated at 90 ° C. for 5 seconds and the surface condition and color tone were evaluated.
[0129]
【The invention's effect】
According to the present invention, a thermal image forming material having a good surface shape and excellent image forming ability, that is, photographic performance can be obtained.
[Brief description of the drawings]
FIG. 1 is a schematic view of a hardener-containing hydrophilic colloid protective layer coating liquid mixing and stirring machine used in the present invention.

Claims (2)

Apply a thermal image forming layer coating solution containing organic silver salt, silver ion reducing agent , photosensitive silver halide and polymer latex and a hydrophilic colloid protective layer coating solution containing a hardener, either sequentially or simultaneously, and then dried. In the method for producing a thermal image forming material, the hardener is a compound selected from polyvalent metal ions, and the hardener is added to the protective layer coating solution from 10 minutes before to immediately before the protective layer is applied. A method for producing a thermal image forming material.   The method for producing a thermal image forming material according to claim 1, which is added from 10 minutes before to 10 seconds before applying the hardener.

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