JPH0555047B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field] The present invention relates to a heat-developable photosensitive material that can obtain a black-white-silver image by heat physical development after exposure. In particular, the present invention relates to a heat-developable photosensitive composition that can be coated using water in the manufacturing process, and a heat-developable photosensitive material using this heat-developable photosensitive composition.

[Prior Art] Silver halide photographic materials subjected to wet development are widely used because of their excellent photographic properties such as sensitivity, gradation control, and image quality. However, in wet development processing, it is necessary to accurately prepare the processing solution, process temperature, and process time. There are also known heat-developable photosensitive materials that are subjected to rapid dry processing using heat development without this wet development process. This heat-developable photosensitive material is
For example, it is described in Fundamentals of Photographic Engineering, Non-Silver Salt Photography Edition (Corona Publishing, 1982), pages 242-255, Japanese Patent Publications No. 43-4921, No. 43-4924, and the like.

This heat-developable photosensitive material is composed of a photosensitive silver halide, a reducing agent, an organic silver salt oxidizing agent, and a hydrophobic binder, and these compositions are dissolved or dispersed in an organic solvent and coated on a support. Photosensitive materials produced from this composition have various problems during production, such as the effects on humans caused by organic solvents, the risk of explosion, and the contamination of the surrounding environment. Hydrophilic binder (e.g. gelatin) without organic solvents
Water-based heat-developable photosensitive materials that can be coated using water as a solvent are also known. For example, JP-A-52-137321, JP-A-53-31611, JP-A-53-
It is described in various publications such as No. 116144, No. 54-46709, and Japanese Patent Publication No. 62-30414. In these heat-developable photosensitive materials, a photosensitive silver halide or an organic silver salt oxidizing agent is synthesized in a hydrophilic binder. The material prepared in this way is the composition described above (organic solvent based).
Compared to the above, it had disadvantages such as a complicated manufacturing process and an inability to obtain a high S/N ratio.

[Problems to be Solved by the Invention] The present invention solves the problems of human impact and dangers such as explosions during the production of heat-developable photosensitive materials, which have conventionally been produced using organic solvents, as well as pollution of the surrounding environment. The aim is to solve these problems and reduce manufacturing costs.

A first object of the present invention is to provide a heat-developable photosensitive composition that can be coated in an aqueous system and to improve the manufacturing process. A second object of the present invention is to provide an inexpensive heat-developable photosensitive material. A third object of the present invention is to provide a heat-developable photosensitive material with excellent characteristics.

[Means for Solving the Problems] An object of the present invention is to disperse photosensitive silver halide in oil droplets in a heat-developable photosensitive composition comprising at least photosensitive silver halide, a reducing agent, and a hydrophilic binder. was achieved by.

The silver halide used in the present invention can be selected from silver chloride, silver bromide, silver chlorobromide, silver iodobromide, silver iodochloride, and silver iodochlorobromide. Preferably silver bromide,
Alternatively, it is silver chlorobromide, silver iodobromide, or silver iodochlorobromide, which is composed of silver bromide in a proportion of 75 mol% or more.
In particular, when using only silver halide as an oxidizing agent for forming a silver image in physical development, silver iodobromide is preferred.

The silver halide of the present invention can be prepared by a known method. A particularly preferred method of preparation is
It is prepared in an organic solvent or with an oil-soluble binder as a protective colloid.
This preparation method is described, for example, in US Pat. No. 3,706,565;
Specifications of No. 3706564 and No. 3713833, Special Publication No. 1983-
No. 1567, No. 52-17415, JP-A-57-186745,
No. 58-139135, No. 58-217927, No. 59-52236
It is stated in each publication. As the photosensitive silver halide, organic silver salts partially converted to silver halide can also be used, but in particular long-chain fatty acid silver and Photosensitive silver halide obtained by reacting halide ions in an amount equal to or more than the equivalent mole is preferred.

The silver halide used in the present invention is chemically sensitized,
For example, sensitization may be carried out by sulfur sensitization, reduction sensitization, noble metal sensitization, or the like. In addition, spectral sensitization can be performed using a sensitizing dye. The sensitizing dyes used include cyanine dyes, merocyanine dyes, complex cyanine dyes, complex merocyanine dyes, hemicyanine dyes, styryl dyes, and hemioxonol dyes, and preferably cyanine dyes, merocyanine dyes, complex cyanine dyes, and complex merocyanine. It is a pigment.

In the present invention, physical development can be promoted by coexisting an organic metal salt, particularly an organic silver salt, with the photosensitive silver halide. Examples of organic silver salts include aliphatic carboxylic acid silver salts such as silver behenate, silver stearate, and silver palmitate, silver benzoate, 2,
Aromatic carboxylic acid silver salts such as silver 4-dichlorobenzoate, 3-mercapto-4-phenyl-1,2,4
- Mercaptide silver salts such as triazole silver, 2-mercaptobenzimidazole silver, 2-mercaptobenzothiazole silver, benzotriazole silver, 5
Examples include imino silver salts such as -chlorobenzotriazole silver, 1,2,4-triazole silver, and saccharin silver. These organic silver salts may be allowed to coexist with the photosensitive silver halide in the oil droplets, or may be made to exist in the hydrophilic binder. In the oil drop,
The same or different organic silver salts may be present in both hydrophilic binders.

The amount of photosensitive silver halide used in the present invention, including photosensitive silver halide or organic silver salt, is 0.1 to 4.0 g/m ² in terms of metallic silver. In the present invention, when photosensitive silver halide is used together with organic silver salt, both can be used in any mixing ratio as needed, but preferably photosensitive silver halide is combined with whole silver salt. The amount is 3 mol% or more.

In the present invention, photosensitive silver halide is dispersed in oil droplets in a hydrophilic binder. The oil droplets used are preferably chemically inert and have a boiling point of 200°C
These are high boiling point organic solvents. As a specific example,
Phthalic acid esters such as dibutyl phthalate and didodecylphthalate, phosphoric acid esters such as triphenyl phosphate, tricresyl phosphate, tri-2-ethylhexyl phosphate,
ethyl benzoates such as 2-ethylhexylbenzoate and dodecylbenzoate, high-boiling alcohols such as ylstearyl alcohol, aliphatic carboxylic acid esters such as dioctyl azelate and isostearyl lactate, and hydrocarbons such as paraffin and dodecylbenzene. I can give it to you. In the present invention, in addition to the high boiling point organic solvent, an auxiliary organic solvent having a boiling point of about 30 to about 100° C. can be used. Specific examples include dichloromethane, trichlene, ethyl acetate, ethyl propionate, methyl ethyl ketone, cyclohexanone, and cyclohexane. The amount of high-boiling organic solvent used in the oil droplets of the present invention is 0.2 to 20 g, preferably 0.2 to 20 g, per 1 g of photosensitive silver halide or photosensitive silver halide containing organic silver salt.
It is 0.5-10g. Quantities outside this range, i.e.
If it is less than 0.2 g, problems will arise in the dispersibility of silver halide, and if it is more than 20 g, a so-called sweating phenomenon will occur, in which a high boiling point organic solvent comes out of the photosensitive material.

The high boiling point organic solvent in which the photosensitive silver halide of the present invention is dispersed is dispersed in the hydrophilic colloid described below in the presence of a surfactant. As for the distribution method,
For example, methods described in US Pat. No. 2,739,888 and US Pat. No. 3,352,681 can be mentioned. Specifically, the photosensitive silver halide is dispersed in a high boiling organic solvent, such as tricresyl phosphate, and a co-solvent, such as ethyl acetate, along with other additives if necessary. Thereafter, a hydrophilic colloid containing a surfactant, e.g.
It can be prepared by mixing it into an aqueous solution of gelatin and emulsifying it using a mixer, colloid mill, etc.

When the reducing agent used in the present invention is heated,
Silver halide development nuclei are used as catalysts to reduce silver ions, and themselves are oxidized and participate in silver image formation.
In the present invention, various known compounds can be used as reducing agents. To give specific examples, developers used in ordinary silver halide photosensitive materials, such as hydroquinone, methylhydroquinone,
Chlorohydroquinone, methylhydroxynaphthalene, N,N'-diethyl-P-phenylenediamine, aminophenol, ascorbic acid, 1-
Examples include phenyl-3-pyrazolidone, and in addition to these, 2,2'-methylenebis(6
-t-butyl-3-methylphenol), 4-
4'-butylidenebis(6-t-butyl-3-methylphenol), 4,4'-thiobis(6-t-butyl-3-methylphenol), etc.
Examples thereof include bisnaphthol-based reducing compounds described in Japanese Patent No. 6074, and sulfonamide phenol-based compounds such as 4-benzenesulfonamidophenol described in Belgian Patent No. 802519.

In addition, in order to create a dye image, JP-A-59-48764
Compounds described in Japanese Patent Application Publication No. 2003-100000, which have reducing properties against silver halide and release hydrophilic dyes, can be used. U.S. Patent No. 3,531,286;
No. 3761270, No. 4021240, Belgian Patent No.
Dye images can be created by combining various phenol developers and couplers described in specifications such as No. 802519. U.S. Patent No. 3985565, U.S. Patent No. 4022617
Hydrophilic leuco dyes described in each specification such as No. 1 can be used.

The method of adding the reducing agent used in the present invention is as follows:
can coexist in the oil droplet together with the photosensitive silver halide. Further, it can be dissolved in a hydrophilic binder or dissolved in oil droplets separate from the photosensitive silver halide and dispersed, or it can be dissolved in the binder and oil droplets simultaneously. A preferred method of addition is to coexist in oil droplets together with photosensitive silver halide. The amount of the reducing agent used is about 0.05 to about 5 mol, preferably about 0.2 to about 2 mol, per 1 mol of total silver of photosensitive silver halide or photosensitive silver halide and organic silver salt. .

The hydrophilic binder used in the present invention is a transparent or semi-transparent hydrophilic colloid, and specific examples include gelatin, gelatin derivatives, cellulose derivatives such as carboxymethylcellulose and methylcellulose, polysaccharides such as Denkuron and gum arabic, Examples include synthetic water-soluble polymers such as vinyl alcohol, polyvinylpyrrolidone, and acrylamide polymers. Two or more of these hydrophilic binders can be used in combination. To further increase the dimensional stability, latex-type dispersed vinyl compounds can be added. The amount of hydrophilic binder used may be any amount that protects the oil droplets and does not impair heat resistance during thermal development. At least 0.01 to 10 parts by weight, preferably 0.1 parts by weight per part by weight of high-boiling organic solvent
~5 parts by weight. Quantities outside this range, i.e.
If it is less than 0.01 parts by weight, problems will arise in dispersing and protecting oil droplets, and if it is more than 10 parts by weight, preferred heat developability will not be obtained.

The hydrophilic binder used in the present invention can be crosslinked and hardened, if necessary, to improve water resistance and heat resistance. As the compound (hardening agent) for this purpose, known compounds can be used. For example, inorganic hardeners such as chrome alum and aluminum alum, aldehyde type hardeners such as formaldehyde and glyogyzal, and N that releases aldehyde.
- Methylol, acetal type hardener, epoxy type hardener, aziridine type hardener, mucohalogen acid type hardener, active halogen type hardener, dichloro-s-
Triazine type hardener, activated olefin type hardener,
Carbodiimide type hardeners, isoxazolium type hardeners, methanesulfonic acid ester type hardeners, active ester type hardeners, etc. can be used.

In the present invention, toning agents can be used.
For example, phthalazone and its derivatives described in U.S. Pat.
Examples include phthalazinedione compounds described in the above publication.

In the present invention, a known antifoggant can be used to prevent thermal fog during development. For example, mercury compounds described in Japanese Patent Publication No. 47-11113, Japanese Patent Publication No. 49-10724,
N described in each publication of No. 25808 and No. 54-23813
-halogeno compounds, US Pat. No. 3,645,739;
Examples include higher fatty acids such as stearic acid and behenic acid, and acid stabilizers such as salicylic acid, tetrabrobenzoic acid and trimellitic acid, which are described in JP-A-48-89720.

In the present invention, in order to promote the redox reaction,
Bases and base precursors can be used. For example, the amines and ammonium compounds described in U.S. Pat. No. 2,410,644;
Amino acid compound described in specification No. 3506444,
Examples include salts of carboxylic acids and bases described in British Patent No. 998949 and US Patent No. 3220846, and aldonamides described in JP-A-50-22625.

In the present invention, as a heat solvent, for example, polyglycols and their derivatives described in U.S. Pat. polar substances such as nilmethane,
1,10-decanediol, biphenyl suberate, etc. can be used.

In the present invention, compounds can be used to prevent photodiscoloration after image formation. For example, the azolethione ethers and blocked azolethiones described in U.S. Pat. No. 3,839,041, the tetrazolylthione compounds described in U.S. Pat. No. 3,700,457, and the compounds described in U.S. Pat. No. 3,707,377. The halogen-containing organic oxidizing agents mentioned above include 1-carbamoyl-2-tetrazoline-5-thiones described in US Pat. No. 3,893,859.

Other additives may also be used in the present invention, such as development accelerators, antistatic agents (layers), ultraviolet absorbers, fluorescent brighteners, filter dyes (layers), and the like.

In the present invention, a heat-developable photosensitive composition containing the above-described photosensitive silver halide, a reducing agent, a hydrophilic binder, and other additives as necessary is coated on a support in a single layer or in multiple layers, and then heated. Developable photosensitive materials can be made. Furthermore, an overcoat polymer layer can be provided on the heat-developable photosensitive layer formed of a single layer or multiple layers. Examples of polymers used in the polymer layer include polyvinyl butyral, polystyrene, polymethyl methacrylate, polyurethane rubber, chlorinated rubber, ethyl cellulose, cellulose acetate butyrate, cellulose acetate, polyvinyl perchloride, polyvinylidene chloride, polycarbonate, and polyvinyl vinylidene. Examples include oil-soluble binders such as Lori, water-soluble polymers such as polyvinyl alcohol, gelatin, methylcellulose, polyvinylpyrrolidone, acrylamide polymers, starch, and dispersed emulsified vinyl polymers. Alternatively, the above polymer may be provided as an undercoat layer on a support, and a heat-developable photosensitive layer may be provided thereon.

The support used in the present invention can be selected from a wide variety of supports. For example, synthetic resin films such as polyethylene, polypropylene, polyethylene terephthalate, polycarbonate, and cellulose acetate, synthetic paper, paper coated with resin films such as polyethylene, papers such as art paper, baryta paper for photographs, and metal plates such as aluminum. (foil), a synthetic resin film having a metal-deposited film, a glass plate, etc.

As a coating method, a roll coating method, an air knife method, a kiss coating method, a curtain coating method, a bar coating method, a hopper coating method, etc. can be used.

The heat-developable photosensitive material obtained by applying the heat-developable photosensitive composition of the present invention is exposed to light from a light source such as a xenon lamp, a mercury lamp, a tungsten lamp, a CRT, or a laser beam, and then at 60 to 180°C, preferably. , heat developed at a temperature of 80-150℃. The development time is preferably about 1 to 60 seconds. As a method for heat development, it is common to bring the material into contact with a heating plate or a heating drum, but it may also be a method of temporarily holding the material in a heated atmosphere, or it may be heated with high frequency heating or infrared light.

[Effects of the Invention] According to the present invention, even when water is used as a solvent, the same photographic properties as when an organic solvent is used, that is,
A heat-developable photosensitive material having maximum density, minimum density, and color tone can be obtained.

[Examples] Example 1 Preparation of silver iodobromide 27 g of silver behenate was dispersed in 600 ml of ethyl alcohol, and 16 g of polyvinyl butyral was further dissolved to prepare a polymer dispersion of silver salt. While maintaining this dispersion at 70°C and stirring, 10.8 g of N-bromosuccinimide dissolved in 120 ml of acetone and N
- 0.72 g of iodosuccinimide was added dropwise over 30 minutes. Then, the temperature was lowered to 40°C and the stirring water 6
The polyvinyl butyral containing silver iodobromide was precipitated. The precipitate was filtered and dried to obtain 45 g of solid polyvinyl butyral containing silver iodobromide. The grain size of this silver iodobromide was 0.08 to 0.10 μm.

Preparation and testing of photosensitive materials 5.0 g of solid polyvinyl butyral containing the above silver iodobromide, 7.0 g of tricresyl phosphate and 50 ml of ethyl acetate were kept at 50°C and the silver iodobromide was redispersed, and then the following reducing agent was used: 2.0g and 5mg of the following sensitizing dye
was dissolved.

reducing agent sensitizing dye Aqueous solution containing 3.0 g of gelatin and 1.0 g of sodium dodecylbenzenesulfonate as a surfactant.
100 g and the above ethyl acetate solution were mixed and emulsified using an ultrasonic disperser. Ethyl acetate was removed from this dispersion under reduced pressure, and the following base precursor 300 was added.
mg and silver amount 0.6 on polyester film.
It was applied at g/m ² .

base precursor A 10 second exposure to 700lux tungsten light was applied through a grayscale wedge (Kodak Step Tablet No. 2) and heat development was performed on a 90°C heat block for 5 seconds. The above operations were performed under red safety light (Examples 2 to 4 were also performed under red safety light). A dark brown image with Dmax of 1.0 and Dmin of 0.08 was obtained.

Comparative Example 1 A heat-developable photosensitive material was prepared according to Example 4 of JP-A-53-31611. This comparative example is an example in which photosensitive silver halide is incorporated into gelatin.

24 g of inert gelatin was dissolved in 800 ml of water at 50°C. Next, 41 g of behenic acid was added and melted by heating at 85°C. Next, add 4g of sodium hydroxide to 100ml of water.
An aqueous solution of sodium behenate and behenic acid was added thereto and cooled to 30°C to prepare a dispersion containing sodium behenate and behenic acid.
An aqueous solution of 17 g of silver nitrate dissolved in 100 ml of water was added to this solution to prepare a silver behenate dispersion containing behenic acid and gelatin. To this dispersion, a silver bromide emulsion (particle size 0.09 to 0.12 μm, weight ratio of silver bromide and gelatin = 2:3) prepared separately using gelatin as a binder was mixed at a weight ratio of 10:1, It was coated onto a polyester film at a silver content of 0.6 g/m ² . Furthermore, the following composition was coated on this coated surface so that the amount of reducing agent was 1 g/m ² .

Sodium benzenesulfinate (0.1% by weight)
Methanol solution) 4ml Phthalazone (4.5% by weight methyl cellosolve solution)
5 ml Hydroquinone (25% by weight acetone solution) 8 ml Polyvinyl butyral (8% by weight acetone solution) 100 ml The obtained photosensitive material was exposed to light in the same manner as in Example 1 and heat developed at 130° C. for 5 seconds. The obtained image had a Dmax of 0.5 and a Dmin of 0.2.

Example 2 2.5 g of the solid polyvinyl butyral containing silver iodobromide obtained in Example 1, 5.0 g of xylene diphenyl phosphate, and 50 ml of ethyl acetate were kept at 50°C to redisperse the silver iodobromide, and then the silver iodobromide was redispersed. Reducing agent 2.0 below
g and 3 mg of the following sensitizing dye were dissolved.

reducing agent sensitizing dye The above ethyl acetate solution was mixed with 100 g of an aqueous solution containing 3.0 g of gelatin, 0.7 g of benzotriazole, and 1.0 g of the following surfactant, and emulsified using an ultrasonic disperser.

surfactant Ethyl acetate was removed from this dispersion under reduced pressure, 300 mg of the base precursor used in Example 1 was added, and the mixture was coated on a polyester film at a silver amount of 0.8 g/m ² . It was exposed to light in the same manner as in Example 1, and thermally developed for 10 seconds on a heat block at 100°C. Dmax is 1.2,
A dark brown image with Dmin of 0.10 was obtained.

Example 3 Preparation of Silver Bromide A polymer dispersion of silver salt was prepared by dispersing 24.5 g of silver stearate in 600 ml of isopropyl alcohol and dissolving 16 g of polyvinyl butyral. This dispersion was kept at 50℃, stirred, and acetone 120%
A solution of 11.3 g of N-bromosuccinimide and 0.01 g of lithium bromide dissolved in 1 ml was added dropwise over 60 minutes. Next, the temperature was lowered to 40° C. and poured into water 6 while stirring to precipitate polyvinyl butyral containing silver bromide. The precipitate was filtered and dried to obtain 45 g of solid polyvinyl butyral containing silver bromide. The particle size of this silver bromide was 0.06 to 0.07 μm.

Preparation and testing of photosensitive materials 0.7 g of the solid polyvinyl butyral containing silver bromide, 4.0 g of silver behenate, 1.5 g of behenic acid, 7.0 g of tricresyl phosphate, 50 ml of ethyl acetate,
Silver bromide and silver behenate were redispersed using a ball mill. Next, 3.0 g of the following reducing agent, 1.0 g of phthalazone as a color toning agent, and 1 mg of the sensitizing dye of Example 1 were dissolved.

reducing agent Further, 100 g of an aqueous solution containing 3.0 g of gelatin, 1.0 g of sodium dodecylbenzenesulfonate as a surfactant, and 60 mg of the following hardening agent were added, and emulsified using an ultrasonic disperser.

Hardener Ethyl acetate was removed from this dispersion under reduced pressure, and the dispersion was coated on a polyester film in an amount of 0.5 g/m ² of silver.
Exposure and heat development were carried out in the same manner as in Example 1. Dmax is
1.3, a black image with Dmin of 0.14 was obtained.

Example 4 A heat-developable photosensitive material was prepared in the same manner as in Example 3, except that 1.2 g of phenol was used as the reducing agent, and exposed and thermally developed in the same manner as in Example 1. Dmax is
1.2, a black image with Dmin of 0.12 was obtained.

Claims (1)

[Scope of Claims] 1. A heat-developable photosensitive composition comprising at least a photosensitive silver halide, a reducing agent, and a hydrophilic binder, characterized in that the photosensitive silver halide is dispersed in oil droplets. Heat-developable photosensitive composition. 2. In a heat-developable photosensitive material having a heat-developable photosensitive layer comprising at least a photosensitive silver halide, a reducing agent, and a hydrophilic binder on a support, the silver halide in the heat-developable photosensitive layer is contained in oil droplets. A heat-developable photosensitive material characterized by being dispersed.