JP2005275025A - Heat developable photographic sensitive material and method for manufacturing the heat developable photographic sensitive material - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a heat developable photographic sensitive material having high humidity resistance (sensitivity and maximum density) and improved blocking resistance and scratch resistance, and to provide a method for manufacturing the heat developable photographic sensitive material. <P>SOLUTION: The heat developable photographic sensitive material has a photosensitive layer containing organic silver salt particles, silver halide particles and a reducing agent on a support, wherein the outermost layer in the photosensitive layer side is formed by applying and drying a coating liquid containing polyvinylidene chloride latex and wax emulsion. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a photothermographic material and a method for producing the photothermographic material. More specifically, the photothermographic material has good humidity resistance and improved blocking resistance and scratch resistance. The present invention relates to a method for producing the photothermographic material.

  Many photosensitive materials that have a photosensitive layer on a support and perform image formation by image exposure are known. Among them, as a system that can simplify environmental preservation and image forming means, there is a technique for forming an image by heat development. In recent years, in the field of photoengraving, reduction of waste processing liquid is strongly desired from the viewpoint of environmental conservation and space saving. Therefore, there is a need for a technology related to photothermographic materials for photoengraving that can be efficiently exposed by a laser scanner or laser imagesetter and can form a clear black image with high resolution and sharpness. It is said that. In these heat-developable photographic light-sensitive materials, the use of solution-type processing chemicals can be eliminated, and a simpler heat-development processing system that does not damage the environment can be supplied to customers.

  Methods for forming images by thermal development have already been disclosed (see, for example, Patent Documents 1 and 2 and Non-Patent Documents 1 and 2).

When performing color printing, the photosensitive material for printing plate making usually uses a plurality of films separated for each color. They are printed on each plate and printed in layers. When films that are separated according to a plurality of colors are stacked, if they do not overlap completely, a phenomenon occurs in which the colors shift when printed. Therefore, in a heat-developable photographic light-sensitive material for printing plate making, it is an important issue how to suppress the dimensional change of the plate due to heat. As a method for improving the heat-resistant dimensional stability of a photosensitive material, a technique for reducing heat shrinkage of a support by carrying out heat treatment while being conveyed at a high temperature of 80 to 200 ° C. and a low tension of 0.04 to 6 kg / cm ² is disclosed. (For example, refer to Patent Documents 3 and 4).

  The photothermographic material is usually a reducible non-photosensitive silver source (for example, an organic silver salt), a catalytically active amount of a photocatalyst (for example, silver halide), and a silver reducing agent, usually dispersed in an organic binder matrix. Contained in the state. The light-sensitive material is stable at normal temperature, but when exposed to a high temperature (for example, 80 ° C. or higher) after exposure, silver is oxidized through a redox reaction between a reducible silver source (which functions as an oxidizing agent) and the reducing agent. Is generated. This redox reaction is promoted by the catalytic action of the latent image generated by exposure. The silver produced by the reaction of the reducible silver salt in the exposed areas provides a black image that contrasts with the unexposed areas and forms an image.

  Such heat-developable photographic light-sensitive materials have a low moisture content in the low-humidity season in winter and the development reaction is difficult to proceed. There is a problem that the amount increases, the development reaction easily proceeds, the sensitivity increases, and the character line width increases.

As a conventional technique, a technique (for example, see Patent Document 5) that uses vinylidene chloride as a protective layer to reduce the influence of a character line width under high humidity is known, but humidity resistance is insufficient. At the same time, it was found that the film strength at the time of development becomes weak, so that a roller mark is attached after conveyance by heat development, or when it is bad, the film adheres to a roll and cannot be conveyed. Similarly, it was found that the scratch resistance deteriorates.
US Pat. No. 3,152,904 US Pat. No. 3,457,075 Japanese Patent Laid-Open No. 10-10676 Japanese Patent Laid-Open No. 10-10777 JP 2001-272742 A D. Morgan, B.M. Shely; Thermally Processed Silver Systems Imaging Processes and Materials Nebulette, 8th edition, Sturge, V.M. Walworth, A.D. Edited by Shepp; 279 pages, 1989

  The present invention has been made in view of the above problems, and an object of the present invention is a photothermographic material having good humidity resistance (sensitivity, maximum density) and improved blocking resistance and scratch resistance. And a method for producing the photothermographic material.

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

(Claim 1)
A photosensitive layer containing organic silver salt particles, silver halide grains and a reducing agent is provided on a support, and an outermost layer on the photosensitive layer side is coated and dried with a coating solution containing a polyvinylidene chloride latex and a wax emulsion. A heat-developable photographic light-sensitive material provided.

(Claim 2)
70% by mass or more of the binder constituting the outermost layer on the photosensitive layer side is a polyvinylidene chloride latex (as a solid content mass), and the content of the vinylidene chloride component of the polyvinylidene chloride in the polyvinylidene chloride latex is 2. The photothermographic material according to claim 1, wherein the content is 70 to 100% by mass.

(Claim 3)
3. The photothermographic material according to claim 1, wherein the moisture permeability of the outermost layer on the photosensitive layer side is 0.1 to 20 g / m ² · 24 hr.

(Claim 4)
4. The photothermographic material according to claim 1, wherein the wax emulsion is paraffinic.

(Claim 5)
5. The photothermographic material according to claim 1, wherein the photosensitive layer contains a nucleating agent.

(Claim 6)
The photothermographic material according to claim 1, wherein the support is a low heat-shrinkable support.

(Claim 7)
When producing the photothermographic material according to any one of claims 1 to 6, after the outermost layer on the photosensitive layer side of the photothermographic material is provided, the photothermographic material is rolled or lined. A method for producing a heat-developable photographic light-sensitive material, which is heat-treated while being conveyed.

  According to the present invention, there are provided a photothermographic material having good humidity resistance (sensitivity and maximum density) and improved blocking resistance and scratch resistance, and a method for producing the photothermographic material. Can do.

  Hereinafter, although the best mode for carrying out the present invention will be described, the present invention is not limited to these.

  As a result of earnestly examining the above problems, the present inventor has excellent humidity resistance in photographic performance by installing a layer containing vinylidene chloride latex and a wax emulsion in the outermost layer on the photosensitive layer side, and further, It has been found that a photothermographic material excellent in blocking resistance and scratch resistance can be obtained.

  The photothermographic material of the present invention has a photosensitive layer containing organic silver salt particles, silver halide grains and a reducing agent on a support, and the outermost layer on the photosensitive layer side is a polyvinylidene chloride latex and a wax emulsion. One feature is that it is provided by coating and drying a coating solution containing the above.

  In the photothermographic material of the present invention, 70% by mass or more of the binder constituting the outermost layer on the photosensitive layer side is a polyvinylidene chloride latex (as a solid content mass), and the poly (vinylidene chloride) latex in the polyvinylidene chloride latex It is preferable that the content rate of the vinylidene chloride component of a vinylidene chloride is 70-100 mass%.

[Outermost layer on the photosensitive layer side]
1. In the present invention, the polyvinylidene chloride latex used in the outermost layer on the photosensitive layer side in the present invention is such that the content of the vinylidene chloride component of the polyvinylidene chloride (copolymer) in the polyvinylidene chloride latex is 70 to 100% by mass. It is preferable that Most preferably, it is 80-100 mass. Moreover, you may contain the multiple types of polyvinylidene chloride copolymer from which the content rate of a vinylidene chloride component differs. In this case, if a copolymer having a vinylidene chloride content of 70 to 100% by mass is contained, for the other components, a polyvinylidene chloride copolymer having a vinylidene chloride content of less than 70% by mass is used. You may contain. In the present invention, the thickness of the outermost layer on the photosensitive layer side is preferably 0.1 μm to 10 μm, more preferably 0.3 μm to 8 μm, and particularly preferably 0.5 μm to 5 μm. If it is thinner than 0.1 μm, the moisture resistance is not sufficient, which is not preferable. On the other hand, if it is thicker than 10 μm, the color becomes yellowish, which is not preferable as a photosensitive material.

  In the present invention, a vinylidene chloride copolymer can be preferably used as the polyvinylidene chloride. As a preferred vinylidene chloride-containing copolymer, a copolymer comprising vinylidene chloride / acrylic acid ester / vinyl monomer having an alcohol in a side chain described in JP-A No. 51-135526, US Pat. No. 2,852,378 Copolymer of vinylidene chloride / alkyl acrylate / acrylic acid described in the above, copolymer of vinylidene chloride / acrylonitrile / itaconic acid described in U.S. Pat. No. 2,698,235, described in US Pat. No. 3,788,856 And a copolymer of vinylidene chloride / alkyl acrylate / itaconic acid. Specific examples of the compound include the following. The numbers in parentheses indicate mass ratios.

Copolymer of vinylidene chloride: methyl acrylate: hydroxyethyl acrylate (83: 15: 2) Copolymer of vinylidene chloride: ethyl methacrylate: hydroxypropyl acrylate (82: 10: 8) Vinylidene chloride: hydroxydiethyl methacrylate (92: 8) ) Copolymer of vinylidene chloride: butyl acrylate: acrylic acid (94: 4: 2) Copolymer of vinylidene chloride: butyl acrylate: itaconic acid (75: 20: 5) Vinylidene chloride: methyl acrylate: itacon Copolymer of acid (90: 8: 2) copolymer of vinylidene chloride: methyl acrylate: methacrylic acid (93: 4: 3) copolymer of vinylidene chloride: monoethyl itaconate (96: 4) Vinylidene: Acrylic nitrile: Acrylic Copolymer of (95: 3.5: 1.5) Copolymer of vinylidene chloride: methyl acrylate: acrylic acid (90: 5: 5) of vinylidene chloride: ethyl acrylate: acrylic acid (93: 5: 2) Copolymer Copolymer of vinylidene chloride: methyl acrylate: 3-chloro-2-hydroxypropyl acrylate (84: 9: 7) Copolymer of vinylidene chloride: methyl acrylate: N-ethanolacrylamide (85: 10: 5) Copolymer of vinylidene chloride: methyl acrylate: acrylic acid (98: 1: 1) Copolymer of silver vinylidene chloride: methyl acrylate: itaconic acid (97: 1: 2) Vinylidene chloride: acrylonitrile: acrylic acid (99: 0.5: 0.5) copolymer vinylidene chloride: ethyl acrylate: acrylic acid (98: 1: ) Copolymer of vinylidene chloride: methyl acrylate: acrylic acid (65: 34: 1) Copolymer of vinylidene chloride: methyl acrylate: itaconic acid (70: 29: 1) Vinylidene chloride: acrylonitrile: acrylic Copolymer of acid (70: 29: 1) Copolymer of vinylidene chloride: ethyl acrylate: acrylic acid (68: 31: 1).

2. Wax emulsion The wax emulsion used in the present invention is obtained by emulsifying wax. Examples of the wax include paraffin wax, candelilla wax, carnauba wax, rice wax, montan wax, ceresin wax, microcrystalline wax, petrolactam, Fisher tribush wax, polyethylene wax, montan wax and derivatives thereof, and microcrystalline wax. And derivatives thereof, hardened castor oil, liquid paraffin, stearamide and the like, and paraffin wax is particularly preferable because it has the effect of crystallizing by heat treatment and improving the moisture-proof effect. The wax emulsion may be prepared by a known method. For example, a wax, a resin, a fluidizing agent and the like may be melted by mixing and heating, and an emulsifier may be added thereto to emulsify. Examples of the resin include rosin, a rosin ester compound, and a petroleum resin. Examples of the fluidizing agent include polyhydric alcohols and esterified products of polyhydric alcohols. After these mixtures are melted, for example, surfactants such as anions, cations, and nonions, or basic compounds such as ammonia, sodium hydroxide, and potassium hydroxide, organic amines, and styrene-maleic acid copolymers are added. It can be made into a wax emulsion by emulsifying.

  Wax emulsions may be used alone or in combination of two or more.

  The melting point of the wax emulsion by differential scanning calorimetry (DSC) is preferably 40 to 100 ° C, more preferably 50 to 80 ° C. Here, if the melting point is less than 40 ° C., the blocking property is deteriorated, which is not preferable. Also, at a temperature higher than 100 ° C., the wax does not sufficiently soften or flow when the coating film is dried when the outermost layer according to the present invention is provided, so that the moisture resistance deteriorates as a result of impairing moisture resistance.

3. Heat treatment The outermost layer according to the present invention is heat treated to improve the moisture-proof effect. This is presumed that the moisture-proof effect is improved by the crystallization of the constituent wax or polyvinylidene chloride by heat treatment. From the above viewpoint, the heat treatment temperature is preferably not less than the glass transition temperature of the constituent polyvinylidene chloride and not more than the melting point of the wax, more preferably not less than the glass transition temperature of the polyvinylidene chloride + 20 ° C. and the melting point of the wax−10 ° C. A longer heat treatment time is better from the above viewpoint, but an appropriate time is selected for the convenience of the production process.
As a heat treatment method, after coating and drying the outermost layer according to the present invention, the heat-developable photographic photosensitive material is wound into a roll form and then heat-treated as it is, and using a transport line after coating and drying. A heat treatment method is preferred.
As a method for heat treatment in the form of a roll, a heat treatment method is preferred at a temperature as low as possible for a long time from the viewpoint of blocking between the films. However, since it is inferior in productivity if it is too long, it is realistic up to 150 hours. In order to prevent blocking, it is preferable to carry out embossing at the edge or central portion of the film or over the entire length, bending the end portion, or partially increasing the thickness of the film. In order to prevent deformation due to the transfer of the winding core, it is preferable that the material and structure have a strength that does not cause bending even when the film is wound and can withstand the heat treatment temperature. The surface of the core is preferably as smooth as possible, and the surface roughness (RMAX) is preferably 2.0 μm or less. Examples of these include a resin roll, a fiber reinforced resin roll, a metal roll, and a ceramic coating roll. If the core diameter is too small, wrinkles and the like are likely to occur in the core part, and therefore it is preferable that the core diameter is large to some extent.

  On the other hand, as a method of performing heat treatment using the transfer line, since the transfer line is transferred, the temperature can be heat-treated near the melting point, and therefore, a temperature and time with high crystallization efficiency can be selected for convenience. A longer time is preferable, but from the viewpoint of productivity and transportability, heat treatment is preferably performed while transporting at a line speed of 5 m / min to 50 m / min. The transport tension is not particularly specified, but a tension of 5 kg / m to 60 kg / m is preferable. If the heat treatment is performed at a line speed or conveying tension other than the above, it is not preferable because wrinkles are generated or the surface property of the support is deteriorated.

  Examples of the heat treatment using the transport line include a method of transporting the film while maintaining a flat state, a transport method using pins and clips, an air transport method, and a roll transport method. Preferred are an air conveyance method and a roll conveyance method, and more preferred is a roll conveyance.

  In any of the heat treatments, the effect is further improved by repeating the cooling-heat treatment in order to promote the crystallization of the wax.

4). Fluorosurfactant The outermost layer according to the present invention preferably contains a fluorosurfactant. The fluorosurfactant may be any of anionic, cationic and nonionic, and among them, anionic ones are preferable. These may be low molecular compounds or high molecular compounds.

5). Others A matting agent may be used for the outermost layer according to the present invention in order to improve scratch resistance. The fine particles added as the matting agent are generally fine particles of an organic or inorganic compound that is insoluble in water, and any of them can be used. For example, U.S. Pat. Nos. 1,939,213, 2,701,245, 2,322,037, 3,262,6782, 3,539,344, third , 767, 448, etc., 1,260,772, 2,192,241, 3,257,206, 3,370, Those well known in the art such as the inorganic matting agent described in each specification such as 951, 3,523,022, and 3,769,020 can be 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. 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 photosensitive material, the particle size, shape, and particle size distribution can be brought into a state as necessary during the preparation of the matting agent or by mixing a plurality of matting agents. preferable.

6). Moisture permeability The moisture permeability of the outermost layer according to the present invention is preferably 0.1 to ²⁰ g / m ² · 24 hr. More preferably, it is 0.1-10 g / m < ² > * 24hr. If it is lower than 0.1 g / m ² · 24 hr, it is necessary to increase the film thickness or increase the WAX ratio, the layer becomes yellowish, the film as a layer becomes weak, and the blocking property deteriorates. ^{On the other hand} , if it exceeds 20 g / m ² · 24 hr, the moisture-proof effect is not exhibited and the humidity resistance of the photographic performance deteriorates.

The method of measuring moisture permeability can be measured according to JIS Z-208 (cup method).
[Photosensitive layer]
1. Organic Silver Salt Particles Organic silver salt particles (hereinafter also referred to as organic silver salts) contained in the photosensitive layer (hereinafter also referred to as photosensitive layer) of the photothermographic material of the present invention are reducible silver sources, Silver salts of organic acids and heteroorganic acids containing a reducible silver ion source, especially long chain (10-30, preferably 5-25 carbon atoms) aliphatic carboxylic acids and nitrogen-containing heterocyclic carboxylic acids preferable. Also useful are organic or inorganic silver salt complexes in which the ligand has a total stability constant for silver ions of 4.0-10.0. Examples of suitable silver salts are described in Research Disclosure (RD) Nos. 17029 and 29963 and include the following: salts of organic acids (eg, gallic acid, oxalic acid, behenic acid, stearic acid, palmitic acid) Acid, lauric acid, etc.); silver carboxyalkylthiourea salts (eg, 1- (3-carboxypropyl) thiourea, 1- (3-carboxypropyl) -3,3-dimethylthiourea, etc.); aldehyde and hydroxy Silver complexes of polymer reaction products with substituted aromatic carboxylic acids (eg, aldehydes such as formaldehyde, acetaldehyde, butyraldehyde and salicylic acid, benzylic acid 3,5-dihydroxybenzoic acid, 5,5-thiodisalicylic acid, etc. Hydroxy-substituted acids); silver salts or complexes of thiones (e.g. 3- (2-carboxyethyl) -4-hydroxymethyl-4-thiazoline-2-thione and 3-carboxymethyl-4-methyl-4-thiazoline-2-thione); imidazole, pyrazole, urazole, 1,2,4- Nitric acid and silver complex or salt selected from thiazole and 1H-tetrazole, 3-amino-5-benzylthio-1,2,4-triazole and benzotriazole; silver salts such as saccharin and 5-chlorosalicylaldoxime A silver salt of mercaptides; Preferred silver sources are silver behenate, silver arachidate or silver stearate.

  The organic silver salt can be obtained by mixing a water-soluble silver compound and a compound that forms a complex with silver, as described in the normal mixing method, the reverse mixing method, the simultaneous mixing method, and Japanese Patent Application Laid-Open No. 9-127643. A controlled double jet method or the like 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. By adding the soap and silver nitrate, an organic silver salt crystal is prepared. At that time, silver halide grains may be mixed.

2. Silver halide grains The silver halide grains contained in the photosensitive layer of the photothermographic material of the invention function as an optical sensor. In the present invention, in order to keep the cloudiness after image formation low and to obtain good image quality, it is preferable that the average particle size is small, the average particle size is preferably 0.03 μm or less, more preferably 0.01 to The range is 0.03 μm. Incidentally, the silver halide grains of the photothermographic material of the present invention are produced at the same time as the preparation of the organic silver salt, or mixed with the silver halide grains at the time of preparing the organic silver salt to prepare an organic It is preferable to form silver halide grains in a fused state with a silver salt to form so-called in situ silver of fine grains. In addition, the measuring method of the average grain diameter of the above-mentioned silver halide grains was taken at 50000 times with an electron microscope, the long side and the short side of each silver halide grain were measured, 100 grains were measured, and the average This is defined as the average particle size.

  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. In the case of non-normal crystals, for example, in the case of spherical, rod-like, or tabular grains, it means the diameter when considering a sphere equivalent to the volume of silver halide grains. The silver halide grains are preferably monodispersed. The monodispersion here means that the monodispersity obtained by the following formula is 40% or less. The particles are more preferably 30% or less, and particularly preferably 0.1 to 20%.

Monodispersity = (standard deviation of particle size) / (average value of particle size) × 100
In the present invention, the silver halide grains are more preferably monodisperse grains having an average grain diameter of 0.01 to 0.03 [mu] m, and the graininess of the image is also improved by using this range.

  The shape of the silver halide grains is not particularly limited, but the ratio occupied by the Miller index [100] plane is preferably high, and this ratio is 50% or more, further 70% or more, particularly 80% or more. Is preferred. The ratio of the Miller index [100] plane is calculated by using the adsorption dependency between the [111] plane and the [100] plane in the adsorption of the sensitizing dye. Tani; Imaging Sci. 29, 165 (1985).

  Another preferred silver halide grain shape is a tabular grain. The tabular grains referred to herein are those having an aspect ratio = r / h of 3 or more when the square root of the projected area is the grain size r μm and the vertical thickness is h μm. Among them, the aspect ratio is preferably 3 or more and 50 or less. The particle size is preferably 0.03 μm or less, more preferably 0.01 to 0.03 μm. These production methods 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. Can do. When these tabular grains are used in the present invention, the sharpness of the image is further improved.

  The composition of the silver halide grains is not particularly limited, and may be any of silver chloride, silver chlorobromide, silver chloroiodobromide, silver bromide, silver iodobromide, and silver iodide. The photographic emulsion used in the present invention is P.I. 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 using a method described in Making and Coating Photographic Emulsion (published by The Focal Press, 1964) by Zelikman et al.

  The silver halide grains used in the present invention preferably contain ions or complex ions of metals belonging to Groups 6 to 10 of the Periodic Table of Elements in order to improve the illuminance failure and to adjust the improvements. As the metal, W, Fe, Co, Ni, Cu, Ru, Rh, Pd, Re, Os, Ir, Pt, and Au are preferable.

  The silver halide grains can be desalted by washing with water using a method known in the art, such as a noodle method or a flocculation method, but may or may not be desalted in the present invention.

  The silver halide grains in the present invention are preferably chemically sensitized. Preferred chemical sensitization methods include sulfur sensitization method, selenium sensitization method, tellurium sensitization method, noble metal sensitization method such as gold compound, platinum, palladium, iridium compound and reduction as well known in the art. A sensitization method can be used.

In the present invention, in order to prevent devitrification of the heat-developable photographic light-sensitive material, the total amount of silver halide grains and organic silver salt is 0.3 to 2.2 g per 1 m ² in terms of silver amount. 5-1.5 g is more preferable. By setting this range, a high-contrast image can be obtained. The amount of silver halide based on the total amount of silver is 50% or less, preferably 25% or less, and more preferably 0.1 to 15% by mass ratio.

  The silver halide grains in the present invention have a maximum light absorption at 350 to 450 μm, and may not particularly contain a sensitizing dye, but may be contained if necessary.

3. Reducing agents Examples of suitable reducing agents contained in the photosensitive layer of the photothermographic material of the present invention are U.S. Pat. Nos. 3,770,448, 3,773,512, and 3,593. , 863, etc. and RD Nos. 17029 and 29963, and the following can be mentioned.

  Aminohydroxycycloalkenone compounds (e.g. 2-hydroxy-3-piperidino-2-cyclohexenone); aminoreductones esters (e.g. piperidinohexose reductone monoacetate) as precursors of reducing agents; N- Hydroxyurea derivatives (eg, Np-methylphenyl-N-hydroxyurea); hydrazones of aldehydes or ketones (eg, anthracene aldehyde phenylhydrazone); phosphoramidophenols; phosphoramidoanilines; polyhydroxybenzenes (E.g. hydroquinone, t-butyl-hydroquinone, isopropylhydroquinone and (2,5-dihydroxy-phenyl) methylsulfone); sulfhydroxamic acids (e.g. Mucinic acid); sulfonamidoanilines (eg, 4- (N-methanesulfonamido) aniline); 2-tetrazolylthiohydroquinones (eg, 2-methyl-5- (1-phenyl-5-tetrazolylthio) hydroquinone) Tetrahydroquinoxalines (eg, 1,2,3,4-tetrahydroquinoxaline); amide oximes; azines; combinations of aliphatic carboxylic acid arylhydrazides and ascorbic acid; combinations of polyhydroxybenzene and hydroxylamine; And / or hydrazine; hydroxanoic acids; combinations of azines and sulfonamidophenols; α-cyanophenylacetic acid derivatives; combinations of bis-β-naphthol and 1,3-dihydroxybenzene derivatives; 5-pyrazolones; 2-phenylindane-1,3-dione, etc .; Chroman; 1,4-dihydropyridines (for example, 2,6-dimethoxy-3,5-dicarboethoxy-1,4-dihydropyridine); Bisphenols (For example, bis (2-hydroxy-3-tert-butyl-5-methylphenyl) methane, bis (6-hydroxy-m-tri) mesitol, 2,2-bis (4-hydroxy-3-methyl Phenyl) propane, 4,4-ethylidene-bis (2-tert-butyl-6-methylphenol)), UV-sensitive ascorbic acid derivatives; hindered phenols; 3-pyrazolidones. Of these, particularly preferred reducing agents are hindered phenols.

The amount of reducing agent used is preferably 1 × 10 ⁻² to 10 mol, in particular 1 × 10 ^{−2 to} 1.5 mol, per mol of silver.

4). Nucleating agent (high contrast agent)
The high contrast agent contained in the photosensitive layer of the photothermographic material of the present invention includes, as a hydrazine compound, RD 23515 (November 1983, P. 346) and the literature cited therein, U.S. Pat. Nos. 4,080,207, 4,269,929, 4,276,364, 4,278,748, 4,385,108, 4, 459,347, 4,478,928, 4,560,638, 4,686,167, 4,912,016, 4,988,604, 4,994,365, 5,041,355, 5,104,769, British Patent 2,011,391B, European Patent 217,310, 301,799 No. 356,898, JP-A-60-179734 61-170733, 61-270744, 62-178246, 62-270948, 63-29751, 63-32538, 63-104047, 63-121838, 63-129337, 63-223744, 63-234244, 63-234245, 63-234246, 63-294552, 63-306438, 64-10233, JP-A-1 -90439, 1-100530, 1-105941, 1-105943, 1-276128, 1-280747, 1-283548, 1-283549, 1-285940 No. 2-2541, No. 2-77057, No. 2-139538, No. 2-196234, No. 196235, 2-198440, 2-198441, 2-198442, 2-20042, 2-221953, 2-219554, 2-285342, 2-285343 No. 2-289843, No. 2-302750, No. 2-304550, No. 3-37642, No. 3-54549, No. 3-125134, No. 3-184039, No. 3-240036, 3-240037, 3-259240, 3-280038, 3-282536, 4-511436, 4-568842, 4-84134, 2-230233, 4 -96053, 4-216544, 5-45761, 5-45762, 5-45763, 5-45764, 5-4 No. 5765, 6-289524, 9-160164 and the like.

  In addition, compounds represented by (Chemical Formula 1) described in JP-B-6-77138, specifically, compounds described on pages 3 and 4 of the same publication, JP-B-6-93082 Compounds represented by the general formula (1) described in the above, specifically, compounds 1 to 38 described on pages 8 to 18 of the same publication, general formula (4) described in JP-A-6-23049 , (5) and (6), specifically, compounds 4-1 to 4-10 described on pages 25 and 26 of the same publication, and compounds 5-1 described on pages 28 to 36 -5-42, and compounds 6-1 to 6-7 described on pages 39 and 40, and compounds represented by general formulas (1) and (2) described in JP-A-6-289520, specifically Specifically, compounds 1-1) to 1-17) and 2-1) described on pages 5 to 7 of the same publication, and JP-A-6-313936. The compounds represented by (Chemical Formula 2) and (Chemical Formula 3) listed above are specifically compounds described on pages 6 to 19 of the same publication, and represented by (Chemical formula 1) described in JP-A-6-313951. Specifically, compounds described on pages 3 to 5 of the same publication, compounds represented by the general formula (I) described in JP-A-7-5610, specifically, Compounds I-1 to I-38 described on pages 5 to 10 and compounds represented by the general formula (II) described in JP-A-7-77783, specifically, pages 10 to 27 Compounds II-1 to II-102, and compounds represented by general formula (H) and general formula (Ha) described in JP-A-7-104426, specifically, pages 8 to 15 of the same publication. Those described in the compounds H-1 to H-44 described on the page can be used.

  Further, other contrast-increasing agents used in the present invention are compounds described on pages 33 to 53 of JP-A No. 11-316437, and more preferably the following general formula (described in JP-A No. 2000-298327) 1), vinyl compounds of general formula (2) and general formula (3) are preferably used.

In the general formula (1), R ¹¹ , R ¹² and R ¹³ each independently represent a hydrogen atom or a substituent, and Z represents an electron-withdrawing group or a silyl group. In the general formula (1), R ¹¹ and Z, R ¹² and R ¹³ , R ¹¹ and R ¹² , and R ¹³ and Z may be bonded to each other to form a cyclic structure. In the general formula (2), R ¹⁴ represents a substituent. In the general formula (3), X and Y each independently represent a hydrogen atom or a substituent, and A and B each independently represent an alkoxy group, an alkylthio group, an alkylamino group, an aryloxy group, an arylthio group, an anilino group, a hetero group A ring oxy group, a heterocyclic thio group or a heterocyclic amino group is represented. In the general formula (3), X and Y, and A and B may be bonded to each other to form a cyclic structure.

  Specific compounds of the general formula (1), general formula (2), and general formula (3) include the following compounds.

  The amount of the high contrast agent contained in the photothermographic material of the present invention is preferably from 0.1 to 0.001 mol, more preferably from 0.05 to 0.005 mol, per 1 mol of silver.

5). Others The binder used in the photosensitive layer and the non-photosensitive layer of the photothermographic material of the present invention is either a hydrophilic binder (a binder or latex that dissolves in water) or a hydrophobic binder (a binder that dissolves in an organic solvent). However, the binder of each layer is preferably a binder that dissolves in the same solvent system. For example, the binder of each layer of the photosensitive layer, the intermediate layer, and the protective layer are all organic solvent-based binders or hydrophilic. It is preferable that the binder be a functional binder.

  The binder used in each layer is transparent or translucent and generally colorless, and natural polymers, synthetic monopolymers and copolymers, and other media that form films are used. Specific examples of the binder include: water-soluble binders such as gelatin, gum arabic, poly (vinyl alcohol), hydroxyethyl cellulose, casein, starch, cellulose acetate, cellulose acetate butyrate, poly (vinyl pyrrolidone), 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) (Eg, poly (vinyl formal) and poly (vinyl butyral)), poly (esters), poly (urethanes), phenoxy resins, poly (vinylidene chloride), poly (epoxides), poly (carbonates), Poly (vinyl vinyl Tate), cellulose esters, poly (amide) and other hydrophobic binders, preferably polyvinyl butyral, cellulose acetate, cellulose acetate butyrate, polyester, polycarbonate, polyacrylic acid, polyurethane and other hydrophobic binders, particularly polyvinyl butyral, Examples thereof include hydrophobic binders such as cellulose acetate, cellulose acetate butyrate and polyester, and latex obtained by polymerizing monomers of those binder resins in water by an emulsion polymerization method or a suspension polymerization method.

  As the main solvent for dissolving the hydrophobic binder, for example, alcohols (methanol, ethanol, propanol), ketones (acetone, methyl ethyl ketone) dimethylformamide, dimethyl sulfoxide, methyl cellosolve and the like are preferably used.

  The Tg of the binder of the photosensitive layer is preferably 40 ° C. or higher. Preferably it is 40-120 degreeC, More preferably, it is 40-100 degreeC, Most preferably, it is 40-80 degreeC. When the temperature is lower than 40 ° C., the developability is increased, and the sensitivity increase (character line width) under high humidity is large, which is not preferable. Moreover, since it becomes higher than 120 degreeC and about the same temperature as heat development temperature, heat transfer is delayed and developability becomes low, which is not preferable.

  In order to control the amount or wavelength distribution of light passing through the photosensitive layer, a filter dye layer may be formed on the same side as the photosensitive layer, or an auxiliary layer such as an antihalation dye layer, a so-called backing layer, may be formed on the opposite side. It is good, and a dye or a pigment may be included in the photosensitive layer. These auxiliary layers may contain a slipping agent such as a polysiloxane compound, wax, liquid paraffin in addition to the binder and matting agent.

  In the heat-developable photographic light-sensitive material of the present invention, various surfactants are used as coating aids, and among them, a fluorosurfactant is preferable for improving charging characteristics and preventing spotted coating failure. Used.

  The photosensitive layer of the heat-developable photographic material of the present invention may have a plurality of layers, and in order to adjust gradation, the photosensitive layer is composed of a high-sensitivity layer / low-sensitivity layer, or a low-sensitivity layer / high-sensitivity layer. Anyway.

  An example of a suitable colorant used in the present invention is disclosed in RD No. 17029.

  Antifoggants may be used in the heat-developable photographic light-sensitive material of the present invention, and these additives may be added to any of the photosensitive layer, the intermediate layer, the protective layer and other forming layers.

  For example, surfactants, antioxidants, stabilizers, plasticizers, coating aids and the like may be used in the photothermographic material of the present invention. As these additives and the other additives described above, compounds described in RD No. 17029 (June 1978, p. 9-15) can be preferably used.

[Low heat shrinkable support]
The low heat-shrinkable support preferably used in the present invention is the heat of the support in order to suppress the dimensional change of the plate due to the temperature (heat) at the time of heat development when used as a photothermographic material for printing plate making. The absolute value of the dimensional change rate at 120 ° C. and 60 seconds corresponding to development is in the range of 0.001 to 0.06% in both the MD (longitudinal) and TD (lateral) directions, preferably 0.001 to 0.04. %, Particularly preferably in the range of 0.001 to 0.02%.

  In the present invention, the measurement of the dimensional change rate is performed as follows. That is, the support is marked with a certain length in the MD and TD directions at 23 ° C. and 55% RH, heated to 120 ° C. for 60 seconds, and then again 23 ° C. and 55% After adjusting the humidity for 3 hours under the condition of RH, the length in each direction is measured, and the dimensional change rate is evaluated. The dimension after heating is subtracted from the dimension before heating and divided by the dimension before heating, and the dimensional change rate is expressed as a percentage as a positive value or a negative value.

  The film used as the base material of the support is preferably a thermoplastic resin, and polyester resin is particularly preferable from the viewpoint of mechanical strength, thermal dimensional stability, and transparency. More preferred are aromatic polyester resins, and specific examples include polyethylene terephthalate and polyethylene naphthalate. The thickness of these films is preferably from 50 μm to 500 μm, more preferably from 75 μm to 300 μm, and even more preferably from 90 μm to 200 μm.

  The support according to the present invention can be achieved by performing the following heat treatment in order to obtain the above dimensional change rate.

  In the heat treatment, it is desirable to reduce the conveyance tension and lengthen the heat treatment time as much as possible in order to reduce the dimensional change during the subsequent heat treatment (thermal development) without hindering the progress of heat shrinkage. The treatment temperature is preferably a temperature range of Tg + 50 to Tg + 150 ° C. of the polyester film, and in that temperature range, the transport tension is preferably 9.8 kPa to 2 MPa, more preferably 9.8 kPa to 980 kPa, and even more preferably 9.8 kPa to It is 490 kPa, and the treatment time is preferably 30 to 10 minutes, more preferably 30 to 5 minutes. By using the above temperature range, conveyance tension range, and processing time, the flatness of the support does not deteriorate due to a partial difference in thermal shrinkage of the support during heat treatment, and fine scratches due to friction with the transfer roll, etc. Etc. can also be suppressed.

  It is also a preferred embodiment that the longitudinal relaxation treatment and / or the lateral relaxation treatment is performed after heat setting before the heat treatment. Moreover, in order to obtain a desired dimensional change rate, the heat treatment is required at least once, and can be performed twice or more as necessary. Further, the heat-treated polyester film is cooled after being cooled from a temperature near Tg to room temperature, and in order to prevent deterioration of flatness due to cooling at this time, at least −5 ° C./second or more until it is lowered to room temperature across Tg. It is preferable to cool at a rate of

  The heat treatment time as the heat treatment condition can be controlled by changing the film conveyance speed or changing the length of the heat treatment zone. If the heat treatment time is too short, the present invention is not effective and the thermal dimensional stability of the support is lowered. Further, if it is 60 minutes or longer, the flatness and transparency of the support are deteriorated, which is not preferable as a support for a heat-developable photographic material. The tension of the heat treatment can be adjusted by adjusting the torque of the take-up roll and / or the feed roll. It can also be achieved by installing a dancer roll in the process and adjusting the load applied to it. When changing the tension during the heat treatment and / or cooling after the heat treatment, a desired tension state may be set by installing dancer rolls before and after these processes and / or in the processes and adjusting their loads. . Further, it is possible to effectively change the conveyance tension by vibration by reducing the span between the heat treatment rolls.

  The support according to the present invention is preferably provided with an undercoat layer before providing the silicon oxide thin film. When providing the undercoat layer, acrylic resin, polyester resin, acrylic-modified polyester resin, polyurethane resin, vinylidene chloride resin, polyvinyl alcohol resin, cellulose ester resin, styrene resin, gelatin and the like are preferable. If necessary, triazine-based, epoxy-based, melamine-based, isocyanate-containing isocyanates including blocked isocyanate, aziridine-based, oxazaline-based crosslinking agents, colloidal silica and other inorganic particles, surfactants, thickeners, dyes, antiseptics An agent or the like may be added.

  It is preferable to provide an antistatic layer on the side opposite to the side on which the silicon oxide thin film is provided. The antistatic layer of the present invention is composed of an antistatic agent and a binder.

A metal oxide is preferably used as the antistatic agent. As an example of the metal oxide, ZnO, TiO ₂ , SnO ₂ , Al ₂ O ₃ , In ₂ O ₃ , SiO ₂ , MgO, BaO, MoO ₂ , V ₂ O ₅ , or a composite oxide thereof is preferable. In particular, SnO ₂ (tin oxide) is preferable from the viewpoints of miscibility with the binder, conductivity, transparency, and the like. As an example including a different element, Sb, Nb, a halogen element or the like can be added to SnO ₂ . The amount of these different elements added is preferably in the range of 0.01 to 25 mol%, particularly preferably in the range of 0.1 to 15 mol%. Tin oxide is preferably in the form of an amorphous sol or crystalline particles. In the case of water-based coating, an amorphous sol is preferable, and in the case of solvent-based coating, the form of crystalline particles is preferable. In particular, from the viewpoint of workability, the form of an amorphous sol with an aqueous coating is preferable from the viewpoint of workability.

As for the method for producing the amorphous SnO ₂ sol, any method such as a method of producing by dispersing SnO ₂ fine particles in an appropriate solvent, or a method of producing from a decomposition reaction of a Sn compound soluble in the solvent in a solvent, etc. But you can. On the other hand, the crystalline particles are described in detail in JP-A-56-143430 and JP-A-60-258541. The conductive metal oxide fine particles can be prepared by first firing the metal oxide fine particles by firing and then heat-treating them in the presence of different atoms to improve conductivity, and secondly by oxidizing the metal oxides by firing. Single and combined methods such as a method of allowing different atoms to coexist at the time of manufacturing fine particles, and a method of introducing an oxygen defect by lowering the oxygen concentration at the time of firing are used.

The average particle diameter of the primary particles of the metal oxide used in the present invention is preferably 0.001 to 0.5 μm, particularly preferably 0.001 to 0.2 μm. The solid amount of the metal oxide used in the present invention is preferably 0.05 to ² g, more preferably 0.1 to 1 g per 1 m ² . The volume fraction of the metal oxide in the antistatic layer in the present invention is 8 to 40 vol%, preferably 10 to 35 vol%. The above range varies depending on the color, shape, composition, etc. of the metal oxide fine particles, but the above range is most preferable from the viewpoint of transparency and conductivity.

  For the binder constituting the antistatic layer, it is preferable to use the same resin as the undercoat layer. In particular, polyester, acrylic-modified polyester, acrylic resin, and cellulose ester are preferable from the viewpoint of dispersibility and conductivity of the metal oxide.

  The antistatic layer is preferably 0.30 to 0.70 μm from the viewpoint of transparency and coating unevenness (interference unevenness). More preferably, it is 0.35-0.55 micrometer. If it is less than 0.30 μm, the desired high-temperature conductivity is ensured, and the scratch resistance when a BC layer is provided is not preferable. On the other hand, when the thickness is 0.70 μm or more, the interference unevenness is strong and the commercial value is deteriorated, and the transparency is deteriorated and cannot be put into practical use.

  As a coating method for the undercoat layer and the antistatic layer, any known coating method can be applied. For example, kiss coat method, reverse coat method, die coat method, reverse kiss coat method, offset gravure coat method, Mayer bar coat method, roll brush method, spray coat method, air knife coat method, impregnation method, curtain coat method, etc. alone or in combination To apply.

  EXAMPLES Hereinafter, the present invention will be specifically described with reference to examples, but the present invention is not limited thereto.

[Preparation of support for photothermographic material]
A PET resin was obtained as follows.

(PET resin)
0.05 parts by mass of magnesium acetate hydrate was added as a transesterification catalyst to 100 parts by mass of dimethyl terephthalate and 65 parts by mass of ethylene glycol, and transesterification was performed according to a conventional method. To the obtained product, 0.05 part by mass of antimony trioxide and 0.03 part by mass of trimethyl phosphate were added. Subsequently, the temperature was gradually raised and the pressure was reduced, and polymerization was carried out at 280 ° C. and 66.5 N to obtain a polyethylene terephthalate (PET) resin having an intrinsic viscosity of 0.70.

  Using the PET resin obtained as described above, a biaxially stretched PET film with an undercoat layer was produced as follows.

(Biaxially stretched PET film with undercoat)
Pelletized PET resin was vacuum-dried at 150 ° C for 8 hours, melted and extruded from a T-die at 285 ° C in a layered form, closely contacted with electrostatic application on a 30 ° C cooling drum, cooled and solidified, and unstretched A film was obtained. This unstretched sheet was stretched 3.3 times in the longitudinal direction at 80 ° C. using a roll type longitudinal stretching machine. The following undercoating liquid A (solid content: 4% by mass) was applied to the obtained uniaxially stretched film by a kiss coating method so that the WET film thickness was 2 g / m ² . Subsequently, using a tenter-type transverse stretching machine, the film was stretched to 50% of the total transverse stretching ratio in the first stretching zone 90 ° C., and further stretched to a total transverse stretching ratio of 3.3 times in the second stretching zone 100 ° C. . Subsequently, pre-heat treatment was performed at 70 ° C. for 2 seconds, and heat setting was further performed at the first fixing zone 150 ° C. for 5 seconds, and heat setting was performed at the second fixing zone 220 ° C. for 15 seconds. Next, 5% relaxation treatment is performed in the lateral (width) direction at 160 ° C. After exiting the tenter, the relaxation treatment is performed in the longitudinal (longitudinal) direction at 140 ° C. using the peripheral speed difference of the drive roll, until the room temperature is reached. After cooling for 60 seconds, the film was released from the clip, slitted, and wound up to obtain a biaxially stretched PET film having a thickness of 125 μm. The biaxially stretched PET film had a Tg of 79 ° C.

<Undercoat coating liquid A>
Acrylic copolymer 40 parts by weight Compound (G) 50 parts by weight Polyglycerin 10 parts by weight Finished with pure water so that the total solid content in the coating solution was 4%.

  Acrylic copolymer: methyl methacrylate / ethyl acrylate / acrylic acid / hydroxyethyl methacrylate / acrylamide = 30 / 47.5 / 10 / 2.5 / 10, mass average molecular weight 500,000

(Heat treatment of support)
Using a suspension type thermal relaxation apparatus, relaxation heat treatment was performed under the conditions of temperature: 180 ° C., transport tension: 230 kPa, time: 15 sec, and further cooled to room temperature at 10 ° C./min, and then wound.

(Antistatic layer)
The undercoat coating solution B was applied to the heat-treated support with a wire bar so as to have a dry film thickness of 0.35 μm, and dried at 80 ° C. for 2 minutes to prepare a support with an antistatic layer.

<Undercoat coating solution B>
Tin oxide sol (SnO ₂ sol synthesized by the method described in Example 1 of JP-B-35-6616 was heated and concentrated so that the solid content concentration was 8.3% by mass, and then adjusted to pH = 10 with ammonia water. 500g
Acrylic modified polyester resin (B-1 described in JP-A No. 2002-156730: solid content: 17.8% by mass) 200 g
300 g of water
[Preparation of Photothermographic Photothermographic Material]
<Application on the back layer side>
The back layer coating solution 1 and the back protective layer coating solution 1 having the following composition were filtered using a filter having an absolute filtration accuracy of 20 μm before coating, respectively, and then applied to the support with an antistatic layer prepared by an extrusion coater. Simultaneous multilayer coating was performed at a rate of 50 m / min so that the total wet film thickness was 60 μm, and drying was performed at 70 ° C. for 4 minutes.

(Back layer coating solution 1)
Methyl ethyl ketone 16.4 g / m ²
Infrared dye A 17mg / m ²
Stabilizer B-1 (Sumitomo Chemical Company Sumitizer BPA) 20 mg / m ²
Stabilizer B-2 (Yoshitomi Pharmaceutical Tomissorb 77) 50 mg / m ²
Cellulose acetate propylate (Eastman Chemical CAP504-0.2) 0.5 g / m ²
Cellulose acetate propylate (Eastman Chemical CAP482-20) 1.5 g / m ²
Compound (C-4) of general formula (1) 20 mg / m ²
Compound (C-8) of general formula (2) 100 mg / m ²

<Back protective layer coating solution 1>
Methyl ethyl ketone 22g / m ²
Fluorine-based surfactant: C ₉ F ₁₇ O (CH ₂ CH ₂ O) ₂₂ C ₉ F ₁₇ 22 mg / m ²
Fluorosurfactant: C ₈ F ₁₇ SO ₃ Li 10 mg / m ²
Cellulose acetate propinate (Eastman Chemical Company:
CAP482) 2.0 g / m ²
Silica (Fuji Devison Psyroid 74; average particle size 7 μm) 12 mg / m ²
(Preparation of silver halide grains)
In 900 ml of pure water, 7.5 g of gelatin and 10 mg of potassium bromide were dissolved, adjusted to a temperature of 35 ° C. and a pH of 3.0, and then brominated at a molar ratio of (96/4) with 370 ml of an aqueous solution containing 74 g of silver nitrate. 10 minutes by a controlled double jet method while keeping 370 ml of an aqueous solution containing 0.436 mol of potassium and potassium iodide and 5 × 10 ⁻⁶ mol / liter of (NH ₄ ) ₂ RhCl ₅ (H ₂ O) at pAg 7.7 Added over time. Thereafter, 0.3 g of 4-hydroxy-6-methyl-1,3,3a, 7-tetrazaindene was added, the pH was adjusted to 5 with NaOH, the average particle size was 0.06 μm, and the variation coefficient of the projected diameter area. Silver halide grains made of cubic silver iodobromide with 8% and a {100} face ratio of 86% were obtained. The emulsion was coagulated and precipitated using a gelatin flocculant and desalted, and 0.1 g phenoxyethanol was added to adjust the pH to 5.9 and pAg 7.5.

(Preparation of organic fatty acid silver emulsion)
10.6 g of behenic acid was placed in 300 ml of water, dissolved by heating at 90 ° C., 31.1 ml of 1 M / L sodium hydroxide was added with sufficient stirring, and the mixture was left as it was for 1 hour. Thereafter, the mixture was cooled to 30 ° C., 7.0 ml of 1 M / L phosphoric acid was added, and 0.01 g of N-bromosuccinimide was added with sufficient stirring. Thereafter, the silver halide grains prepared above were added with stirring in a state heated to 40 ° C. so that the amount of silver was 10 mol% with respect to behenic acid. Further, 25 ml of 1 M / L silver nitrate aqueous solution was continuously added over 2 minutes, and the mixture was left for 1 hour with stirring.

  To this emulsion, polyvinyl butyral dissolved in ethyl acetate was added and stirred sufficiently, and then allowed to stand to separate into an ethyl acetate phase containing silver behenate grains and silver halide grains and an aqueous phase. After removing the aqueous phase, silver behenate particles and silver halide particles were collected by centrifugation. Thereafter, 20 g of synthetic zeolite A-3 (spherical) manufactured by Tosoh Corp. and 22 ml of isopropyl alcohol were added and left for 1 hour, followed by filtration. Further, 3.4 g of polyvinyl butyral and 23 ml of isopropyl alcohol were added, and the mixture was sufficiently stirred at 35 ° C. and dispersed at a high speed to complete the preparation of the organic fatty acid silver emulsion.

<< Coating on the photosensitive layer side >>
<Application of photosensitive layer and protective layer>
A photosensitive layer coating solution and a protective layer coating solution are prepared so as to be a photosensitive layer and a protective layer having the following composition, respectively, and coated on an opposite side of the back layer surface side using an extrusion coater and dried. A protective layer was provided.

(Photosensitive layer composition)
Organic fatty acid silver emulsion 1.4g (in silver) / m ²
Pyridinium hydrobromide perbromide 1.5 × 10 ⁻⁴ mol / m ²
Calcium bromide 1.8 × 10 ⁻⁴ mol / m ²
2- (4-Chlorobenzoyl) benzoic acid 1.5 × 10 ⁻³ mol / m ²
Infrared sensitizing dye 1 4.2 × 10 ⁻⁶ mol / m ²
2-mercaptobenzimidazole 3.2 × 10 ⁻³ mol / m ²
2-Tribromomethylsulfonylquinoline 6.0 × 10 ⁻⁴ mol / m ²
4-methylphthalic acid 1.6 × 10 ⁻³ mol / m ²
Tetrachlorophthalic acid 7.9 × 10 ⁻⁴ mol / m ²
1,1-bis (2-hydroxy-3,5-dimethylphenyl) -3,5,5-
Trimethylhexane 4.8 × 10 ⁻³ mol / m ²
Infrared dye A 3 × 10 ⁻⁵ mol / m ²
Compound (C-38) represented by general formula (1) 0.5 × 10 ⁻³ mol / m ²
As the solvent, methyl ethyl ketone, acetone, and methanol were appropriately used.

(Protective layer composition)
Cellulose acetate butyrate (Eastman Chemical) CAP381-20 / cellulose acetate propinate (Eastman Chemical) CAP504-05 = 2/8 4 g / m ²
Phthalazine 3.2 × 10 ⁻³ mol / m ²
Silica (Fuji Devison Psyroid 74; average particle size 7 μm)
100 mg / m ²
As the solvent, methyl ethyl ketone, acetone, and methanol were appropriately used.

<Applying outermost layer>
A coating solution is prepared so as to be an outermost layer having the following composition (water is appropriately used as a solvent), filtered using a filter having an absolute filtration accuracy of 20 μm, and then the protective layer (photosensitive layer) prepared above with a reduced pressure extrusion coater. The film is applied at a rate of 30 m / min so that the wet film thickness is 15 μm and the dry film thickness is as shown in Table 1, dried at 68 ° C. for 1 minute, and further conveyed to the line at 68 ° C. Were subjected to heat treatment for 10 minutes to prepare heat-developable photographic material samples 1-8.

(Outermost layer composition)
Polyvinylidene chloride latex (listed in Table 1) (Amount listed in Table 1)
Wax emulsion (described in Table 1) (Amount described in Table 1)
Fluorine-based surfactant F-1: C ₈ F ₁₇ SO ₃ Li 20 mg / m ²
Matting agent (Fuji Devison Psyroid 74; average particle size 7 μm) 20 mg / m ²
[Evaluation methods]
<Photographic performance>
(exposure)
A single channel cylindrical inner surface type laser exposure apparatus equipped with a semiconductor laser having a beam diameter (FWHM ½ of the beam intensity) of 12.56 μm, a laser output of 50 mW, and an output wavelength of 783 nm for each of the photothermographic materials produced. Were used under the conditions of a mirror rotation number of 60000 rpm and an exposure time of 1.2 × 10 ⁻⁸ seconds. The overlap coefficient at this time was 0.449, and the laser energy density on the surface of the photothermographic material was 75 μmJ / cm ² .

(Heat development)
The development was performed by thermal development using a film processor model 2771 manufactured by Imation at 120 ° C. for 48 seconds. At that time, exposure was performed in a room adjusted to 23 ° C. and 50% RH, and development processing was performed in an environment of 23 ° C. 20% RH and 23 ° C. 80% RH, respectively.

(Evaluation of photographic performance)
A heat-developable photographic material was prepared at 28 ° C. and 80% humidity for 12 hours (referred to as high humidity) and at 18 ° C. and 20% humidity controlled for 12 hours (referred to as low humidity). Processing was performed.

  Sensitivity increase at high humidity (high humidity sensitivity) by calculating the difference in sensitivity after treatment at 18 ° C. 20% and 26 ° C. 80% RH (relative sensitivity with respect to 100 in the case of low humidity of sample 1) Ascending). The maximum concentration (low humidity Dmax) in a low humidity environment was also evaluated. Concentration measurement was performed with a Macbeth TD904 densitometer.

[blocking]
Each sample was cut into 6 pieces each having a size of 3.5 cm × 10 cm, and left for 1 day in an atmosphere of 35 ° C. and 80% RH so as not to contact each other. Thereafter, six samples were stacked and left to stand in the same atmosphere for one day while applying a load of 800 g. Then, with the load applied, the sample was left for 1 day in an atmosphere of 23 ° C. and 50% RH, and then the sample was peeled off. The adhesive state when peeled off was evaluated. The evaluation criteria are as follows.

Rank A: Peeling without resistance, no adhesion marks Rank B: Peeling without resistance, but adhesion marks can be seen in less than 20% of the total area Rank C: Peeling without resistance, but adhesion marks are 20-60% of the total area Rank D: Feels resistance to peeling, adhesion marks are found in 20% or more of the total area Rank E: Resistance to peeling, peeling of hydrophilic binder is observed (scratch resistance test)
Immediately after the heat development treatment, each sample was attached to a flat, flat surface without unevenness with the tape with the surface of the outermost layer on the photosensitive layer side facing up, and the surface of the sample corresponding to each sample was placed on the back layer side. The surface was rubbed at a pressure of 100 g / cm ² for 10 reciprocations over a distance of 10 cm. This sample was evaluated according to the following criteria.

○: No scratch ○ △: Level at which scratches appear faint (1-2)
Δ: 1 to 2 scratches are visible Δ ×: 3 to 5 scratches are visible ×: 6 or more scratches are visible The results are shown in Table 1.

A: Copolymer of vinylidene chloride: methyl acrylate: hydroxyethyl acrylate (93: 5: 2) B: Copolymer of vinylidene chloride: methyl acrylate: hydroxypropyl acrylate (40:50:10) C: Vinylidene chloride: butyl Copolymer of acrylate: acrylic acid (80: 16: 4) D: Copolymer of vinylidene chloride: butyl acrylate: acrylic acid (96: 3: 1) A: EMUSTAR-0135 (manufactured by Nippon Seiwa Co., Ltd.) Melting point: 61 ° C., paraffin D: manufactured by Nippon Seiwa Co., Ltd., EMUSTAR-0001 (melting point: 83 ° C.), microcrystalline U: manufactured by Nippon Seiwa Co., Ltd., EMUSTAR-0413 (melting point: 83 ° C.), carnauba From Table 1, the photothermographic material of the present invention has good humidity resistance (sensitivity, maximum density), and It can be seen that blocking resistance and scratch resistance are improved and excellent (suitable as a heat-developable photosensitive material for printing).

Claims (7)

A photosensitive layer containing organic silver salt particles, silver halide grains and a reducing agent is provided on a support, and an outermost layer on the photosensitive layer side is coated and dried with a coating solution containing a polyvinylidene chloride latex and a wax emulsion. A heat-developable photographic light-sensitive material provided. 70% by mass or more of the binder constituting the outermost layer on the photosensitive layer side is a polyvinylidene chloride latex (as a solid content mass), and the content of the vinylidene chloride component of the polyvinylidene chloride in the polyvinylidene chloride latex is 2. The photothermographic material according to claim 1, wherein the content is 70 to 100% by mass. 3. The photothermographic material according to claim 1, wherein the moisture permeability of the outermost layer on the photosensitive layer side is 0.1 to 20 g / m ² · 24 hr. 4. The photothermographic material according to claim 1, wherein the wax emulsion is paraffinic. 5. The photothermographic material according to claim 1, wherein the photosensitive layer contains a nucleating agent. The photothermographic material according to claim 1, wherein the support is a low heat-shrinkable support. When producing the photothermographic material according to any one of claims 1 to 6, after the outermost layer on the photosensitive layer side of the photothermographic material is provided, the photothermographic material is rolled or lined. A method for producing a heat-developable photographic light-sensitive material, which is heat-treated while being conveyed.