JPH0968772A - Heat developable photosensitive material - Google Patents

Abstract

PROBLEM TO BE SOLVED: To ensure superior preservability by using nonphotosensitive silver salt particles as acicular crystals having major and minor axes and regulating the average major and minor axis sizes of the acicular nonphotosensitive silver salt grains to a specified range each. SOLUTION: Nonphotosensitive silver salt particles as acicular crystals having major and minor axes are used, the average major axis size of the acicular nonphotosensitive silver salt grains is regulated to 0.10-5μm, preferably 0.10-4μm, especially preferably 0.10-3μm, and the average minor axis size is regulated to 0.01-0.20μm, preferably 0.01-0.15μm, especially preferably 0.01-0.10μm. A dye spectrally sensitizing silver halide particles in a wavelength region in the range of 750-1,400nm when adsorbed on the particles is also used.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an infrared-sensitive heat-developable photographic light-sensitive material, and more particularly to a photographic light-sensitive material for a laser imagesetter or a laser imager (hereinafter referred to as LI light-sensitive material), More specifically, the present invention relates to an infrared-sensitive photothermographic material having excellent storage stability.

[0002]

2. Description of the Related Art In recent years, there has been a strong demand in the medical field to reduce the amount of processing waste liquid from the viewpoint of environmental protection and space saving.
So, laser imagesetter or laser
There is a need in the art for photothermographic materials for medical diagnostics and photographic applications that can be efficiently exposed by an imager. The system for these heat-developable photographic materials eliminates the use of solution-based processing chemicals and can provide the customer with a simpler and environmentally friendly heat treatment system.

On the other hand, semiconductor laser technology, which has made rapid progress in recent years, has enabled downsizing of medical image output devices. Naturally, a technique of infrared-sensitive photothermal silver halide photographic material which can use a semiconductor laser as a light source has also been developed, and as a spectral sensitizing technique, Japanese Patent Publication No. 3-10391, Japanese Patent Publication No. 6-52387, and Japanese Unexamined Patent Publication No. 5-341432. Japanese Patent Laid-Open Nos. 6-194781 and 6-301141, and Japanese Patent Laid-Open No. 7-13295 and U.S. Pat. No. 5,380,635 are disclosed as techniques for preventing halation. In the case of a light-sensitive material that is premised on infrared exposure, the visible absorption of sensitizing dyes and antihalation dyes can be significantly reduced, and a light-sensitive material having substantially no color can be provided.

However, a dye which absorbs infrared rays and spectrally sensitizes generally has a high HOMO and thus has a strong reducing ability, and tends to reduce silver ions in the light-sensitive material to deteriorate the fog of the light-sensitive material. In particular, there is a problem that remarkable changes in performance are caused in storage under conditions such as high temperature and high humidity and in storage for a long time.

As a solution to the problem of the storability of such a light-sensitive material in a wet photographic material, a compound which forms a sparingly soluble salt or a complex with silver ions is added and adsorbed on silver halide grains. It is known that the material can be stabilized, and JP-A-2-68539, No. 10
The compounds described in page 17, lower left column, line 17 to page 11, upper left column, line 7 and page 3, lower left column, line 2 to page 4, lower left column, are known. On the other hand, photothermographic materials contain not only silver halide grains but also many non-photosensitive silver salts, and compounds effective in wet photographic materials cannot exhibit their effects because their adsorption to silver halide grains is inhibited.

[0006]

SUMMARY OF THE INVENTION It is an object of the present invention to provide an infrared-sensitive photothermographic material having excellent storage stability.

[0007]

The object of the present invention has been attained by the following means. (1) In a photothermographic material having photosensitive silver halide particles spectrally sensitized in the range of 750 to 1400 nm and a non-photosensitive silver salt, the non-photosensitive silver salt particles are needles having a major axis and a minor axis. A heat-developable light-sensitive material, characterized in that the acicular crystal grains of the non-photosensitive silver salt have an average major axis size of 0.10 μm or more and 5 μm or less and an average minor axis size of 0.01 μm or more and 0.20 μm or less.

(2) The photothermographic material according to (1), wherein the non-photosensitive silver salt is a silver salt of a fatty acid.

[0009]

BEST MODE FOR CARRYING OUT THE INVENTION The present invention is described in detail below. The non-photosensitive silver salt in the present invention is an organic silver salt and is relatively stable to light, but at 80 ° C. or higher in the presence of an exposed photocatalyst (such as a photographic silver salt) and a reducing agent. A silver salt that forms a silver image when heated to. The organic silver salt may be any organic substance containing a source capable of reducing silver ions. Silver salts of organic acids, especially (having 10 to 3 carbon atoms)
Long chain fatty carboxylic acids (0, preferably 15-28) are preferred. The organic silver salt is preferably used in an amount of about 5 to 3 in the image forming layer.
It should constitute 0% by weight. 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 silver salt of an aliphatic carboxylic acid include silver behenate, silver arachidate, silver stearate, silver oleate, silver laurate,
Silver caproate, silver myristate, silver palmitate, silver maleate, silver fumarate, silver tartrate, silver linoleate, silver butyrate and silver camphorate, including mixtures thereof, but most preferably silver behenate, Silver arachidate, silver stearate and mixtures thereof.

It has also been found that silver half soaps are convenient, especially silver behenate and equimolar amounts of behenic acid prepared by precipitation from a commercially available aqueous solution of behenic acid and having an analytical silver content of about 14.5%. A mixture is a preferred example. When a transparent support is used, free behenic acid may devitrify the photographic light-sensitive material, so that about 4 to 5
It is also possible to use flusoap behenate with an amount of free behenic acid not exceeding 100% and an analytical silver content of about 25.2%. The methods used to make silver soap dispersions are well known in the art and are described in Research Disclosure, April 1983, Item No. 2281.
No. 2, "Research Disclosure" 1983/1
January, Item No. 23419 and US Pat. No. 3,9.
85,565.

These organic silver salts are generally needle-shaped crystals having a crystal structure having a short axis and a long axis, and their size distributions are as follows: stirring at the time of preparing the silver salt, temperature, time for preparing the silver salt, or silver salt. It can be controlled by the dispersion method after adjustment, time and the like.
There are various dispersion means after preparation of silver salt, such as a ball mill,
A dispersing machine such as a sand mill or a colloid mill, a dispersing machine such as a vibrating ball mill, a planetary ball mill, a jet mill, a roll mill, a manton gourin, a microfluidizer, or a disc impeller mill can be arbitrarily selected.

In any case, it is preferable to use a solvent at the time of dispersion and also to use a polymer in combination, because the size of the non-photosensitive silver salt of the present invention can be easily realized. Further, a surfactant for dispersion can be used if necessary.

The non-photosensitive silver salt used in the present invention has an average minor axis size of 0.01 μm or more and 0.20 μm or less, an average major axis size of 0.10 μm or more and 5 μm or less, and more preferably an average minor axis size of 0.01 μm or more and 0.15 μm or more. The average major axis size is 0.10 μm or more and 4 μm or less, most preferably the average minor axis size is 0.01 μm or more and 0.10 μm or less, and the average major axis size is 0.10 μm or more and 3 μm or less.

The infrared sensitizing dye used in the present invention will be described. The dye used in the present invention may be any one which, when adsorbed on silver halide grains, spectrally sensitizes the silver halide grains in any wavelength range of 750 to 1400 nm. Specifically, the photosensitive silver halide can be spectrally advantageously sensitized by various known dyes, including cyanine, merocyanine, styryl, hemicyanine, oxonol, hemioxonol, and xanthene dyes. Useful cyanine dyes include, for example, thiazoline nuclei, oxazoline nuclei, pyrroline nuclei, pyridine nuclei,
It is a cyanine dye having a basic nucleus such as an oxazole nucleus, a thiazole nucleus, a selenazole nucleus, and an imidazole nucleus. Preferred useful merocyanine dyes include, in addition to the above basic nuclei, acidic nuclei such as thiohydantoin nucleus, rhodanine nucleus, oxazolidinedione nucleus, thiazolinedione nucleus, barbituric acid nucleus, thiazolinone nucleus, malononitrile nucleus and pyrazolone nucleus. Including. Among the above cyanine and merocyanine dyes, those having an imino group or a carboxyl group are particularly effective. In particular, the sensitizing dye used in the present invention is described in US Pat.
1, 279, 3rd, 719, 495, 3rd, 8th
77, 943, British Patents 1,466,201, 1,469,117, 1,422,057,
JP-B-3-10391, JP-B-6-52387, JP-A-5-3414323, JP-A-6-194781
No. 6,961,114, JP-A-6-301141, and may be appropriately selected from known dyes, and can be located in proximity to a photocatalyst by a known method. The special sensitizing dyes can generally be used in an amount of about 1 × 10 ⁻⁵ mol to about 1 mol per mol of silver halide. Also, a desired spectral sensitization spectrum can be obtained by mixing a plurality of dyes.

The spectral sensitizing dyes used in the present invention are shown below by general formulas, but the present invention is not limited to these compounds.

[0016]

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[0017]

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[0018]

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In the formula, each of R ₁ and R ₂ is an alkyl group,
Represents an aryl group, an allyl group, an aralkyl group, or a cycloalkyl group, each of Z ₁ and Z ₂ represents an atom necessary for completing a 5- or 6-membered heterocycle, and X ⁻ represents an anion, When R ₁ and / or R ₂ itself contains an anion, X ⁻ is absent. M ⁺ represents a cation. R ₃ and R ₄ represent an alkyl group, an aryl group, a cycloalkyl group, or a structure in which R ₃ and R ₄ are linked, and represent a cycloalkylene skeleton.

The structure of the dye in the present invention will be described in more detail. Both R ₁ and R ₂ (same or different) can be selected from the group of known substituents of the type contained in the cyanine nitrogen atom of the cyanine dye. , Especially Japanese Examined Japanese Patent Publication Sho 51-4
It can be selected from a substituent group belonging to exactly the same range as described in JP-A No. 1061.

Among these, the substituents of R ₁ and R ₂ which are particularly effectively used are unsubstituted alkyl groups such as methyl, ethyl, propyl, isopropyl, butyl and isobutyl, carboxymethyl, carboxyethyl, carboxypropyl, Carboxyalkyl groups such as carboxybutyl, sulfoalkyl groups such as sulfoethyl, sulfopropyl and sulfobutyl, sulfate alkyl groups such as sulfatepropyl and sulfatebutyl, hydroxyalkyl groups, and further N- (methylsulfonyl) -N-substituted alkyl groups such as carbamyl-methyl group, γ- (acetyl-sulfamyl) -butyl group, aralkyl groups such as allyl group and benzyl group, substituted aralkyl groups such as carboxybenzyl and sulfobenzyl, aryl groups such as phenyl group , Cal Kishifeniru, substituted aryl groups, such as sulfophenyl, cycloalkyl groups such as cyclohexyl may be mentioned as examples.

Z ₁ and Z ₂ (same or different) each represent an atomic group necessary for completing a 5- or 6-membered heterocycle, and particularly in the heterocyclic series described in JP-B-51-41061. Can be selected arbitrarily.

Typical skeletons thereof include, for example, thiazole, 4-methylthiazole, 4-phenylthiazole,
Thiazole series nuclei such as 4,5-dimethylthiazole, benzothiazole, 5-chlorobenzothiazole,
Benzothiazole series nuclei such as 5,6-dimethylbenzothiazole and 5,6-dimethoxybenzothiazole, naphtho [2,1-d] thiazole, naphtho [1,2]
-D] thiazole, 5-methoxynaphtho [1,2-d]
Naphthothiazole series nuclei such as thiazole, thionaphthene [7,6-d] thiazole series nuclei such as 7-methoxythionaphtho [7,6-d] thiazole, and 4-
Oxazole series nuclei such as methyloxazole, 5-methyloxazole, 4-phenyloxazole, and 4,5-dimethyloxazole, and benzoxazole, 5
-Chlorobenzoxazole, 5-methylbenzoxazole, 5,6-dimethylbenzoxazole, 5-methoxybenzoxazole, 5-hydroxybenzoxazole and other benzoxazole series nuclei and naphtho [1,2-d] oxazole and the like. Naphthoxazole series nuclei, selenazole series nuclei such as 4-methylselenazole, benzoselenazole, 5-methylbenzoselenazole, benzoselenazole series nuclei such as 5-methoxybenzoselenazole, naphtho [2,1 -D] naphthoselenazole series nuclei such as selenazole, thiazoline, thiazoline series nuclei such as 4-methylthiazoline 4,4-bishydroxymethylthiazoline, oxazoline series nuclei, selenazoline series nuclei, quinoline, 6-methyl Quinoline, 6 Ethoxy quinoline, 6-naphthoxy quinoline etc. 4 quinoline series of nuclear, 1-isoquinoline series of nucleus, and the 3-isoquinoline series, 3,3-dimethylindolenine, 3,3-dimethyl-5-chloro -
Nuclei of 3,3-dialkylindolenine series such as indolenine and 3,3,5-trimethylisoindolenine,
Pyridine series cores such as pyridine and 5-methylpyridine, 1-ethyl-5,6-dichlorobenzimidazole, 1-hydroxyethyl-5,6-dichlorobenzimidazole, 1-ethyl-5-chlorobenzimidazole, 1 -Ethyl-5-fluoro-6-cyanobenzimidazole, 1-ethyl-5-ethylsulfonylbenzimidazole, 1-ethyl-5-methylsulfonylbenzimidazole, 1-ethyl-5-trifluoromethylsulfonyl-benzimidazole, 1 -Ethyl-5
-A group of skeletons that completes the benzimidazole series of nuclei, such as trifluoromethylsphinylbenzimidazole.

X ^- is chlorine ion, bromine ion, iodine ion, perchlorate ion, benzenesulfonate ion, p-
It represents an anion such as a toluene sulfonate ion, a methyl sulfate ion, an ethyl sulfate ion, and a propyl sulfate ion, but R ₁ and / or R ₂ itself is an anionic group, for example, —SO ₃ —, —OSO ₃ —, —COO. ^-, -SO ₂ N - -,
^{_{-SO 2 -N - -CO -, -}} SO 2 -N - -SO 2 - when, including X ^- is absent.

M ⁺ represents a cation such as a hydrogen cation, a metal cation, or an inorganic or organic onium cation (ammonium, pyridinium, etc.).

In the present invention, R ₃ and R ₄ (same or different) can be selected from a group of substituents belonging to the same range as R ₁ and R _{1 in} principle. Also, R ₃
R ₄ and R ₄ may be linked to each other to form a cycloalkylene skeleton such as a cyclohexylene skeleton or a cyclopentylene skeleton. A part of the cycloalkylene skeleton may be substituted with an atom such as oxygen or nitrogen other than carbon atom, and may form, for example, a morpholine skeleton or a piperazine skeleton. An example of the structure of the dye represented by the above general formula is shown below.

[0027]

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[0028]

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[0029]

[Chemical 6]

The heat-developable photographic emulsion of the present invention is composed of one or more layers on a support. The one-layer constitution preferably contains an organic silver salt, a silver halide, and a developer and a binder, and optionally additional materials such as a toning agent, a coating aid and other auxiliary agents. The two-layer configuration is
It is preferred to include the organic silver salt and silver halide in the first emulsion layer (usually the layer adjacent to the support) and some other ingredients in the second or both layers. However, a two-layer construction comprising a single emulsion layer containing all components and a protective topcoat is also contemplated.

It may be advantageous to add a mercury (II) salt as an antifoggant to the emulsion layers as needed to practice the invention. Preferred mercury (II) salts for this purpose are mercury acetate and mercury bromide. The photosensitive silver halide used in the present invention can be used generally in the range of 0.75 to 25 mol%, preferably 2 to 20 mol% of the organic silver salt.

The silver halide can be any photosensitive silver halide such as silver bromide, silver iodide, silver chloride, silver bromoiodide, silver chlorobromoiodide, silver chlorobromide and the like. The silver halide is photosensitive and may have any shape including a cubic shape, an orthorhombic shape, a plate shape, a tetrahedral shape, and the like, but is not limited thereto. May grow.

The silver halide used in the present invention is
Can be used without modification. However,
Chemically sensitized with a chemical sensitizer such as a compound containing sulfur, selenium, tellurium, a compound containing gold, platinum, palladium, rhodium or iridium, a reducing agent such as tin halide, or a combination thereof. be able to. Details of these procedures are described in T. James, "The Theory of the Photographic Process, 4th Edition, Chapter 5, pp. 149-169."

The silver halide can be added to the emulsion layers in any manner that places them in close proximity to catalyze the organic silver salt. The silver halide and organic silver salt, separately formed or "preformed" in the binder, can be mixed before use to prepare a coating solution, but both are mixed in a ball mill for an extended period of time. Is also effective. Further, it is also effective to use a method which comprises adding a halogen-containing compound to the prepared organic silver salt and converting a part of silver of the organic silver salt into silver halide.
Methods for preparing these silver halide and organic silver salts and methods for mixing them are known in the art, "Research Disclosure," June 1978, Item No. 17029 and U.S. Pat. No. 3,7.
00, 458.

The preformed silver halide emulsions of this invention may be unwashed or washed to remove soluble salts. In the latter case, for example, U.S. Pat.
618, 556, 2, 614, 928, 2, 565, 418, 3, 241, 969, and 2, 489, 341, according to the procedure described in The salt may be removed by cold coagulation and leaching, or the emulsion may be coagulated and washed.

In general, a matting agent is used to give a matting degree to the light-sensitive material. The matting agent is generally fine particles of an organic or inorganic compound insoluble in water. Any matting agent can be used. For example, US Pat.
9,213, 2,701,245, 2,32
No. 2,037, No. 3,262,782, No. 3,53
No. 9,344, No. 3,767,448 and other organic matting agents described in each specification, No. 1,260,772, No. 2,
192, 241, 3,257, 206, 3,3
70,951, 3,523,022, 3,76
Inorganic matting agents described in each specification such as No. 9,020 and the like well known in the art can be used. For example, specifically as an example of an organic compound that can be used as a matting agent, as an example of a water-dispersible vinyl polymer, polymethyl acrylate, polymethyl methacrylate, polyacrylonitrile, acrylonitrile-α-methylstyrene copolymer, polystyrene , Styrene-divinylbenzene copolymer, polyvinyl acetate, polyethylene carbonate, polytetrafluoroethylene, etc. Examples of cellulose derivatives are methyl cellulose, cellulose acetate, cellulose acetate propionate, etc. Examples of starch derivatives are carboxy starch, carboxynitrophenyl Gelatin which has been hardened with a known hardening agent such as starch, urea-formaldehyde-starch reaction product, etc. and hard gelatin such as coacervate hardened into fine capsule hollow particles are preferable. It can be used properly. 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, and diatomaceous earth can be preferably used. The above matting agents can be used by mixing different types of substances as necessary. The size and shape of the matting agent are not particularly limited, and those having an arbitrary particle size can be used. In practicing 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, the matting agent is the haze of the sensitive material,
Since it greatly affects the surface gloss, it is preferable that the particle size, the shape, and the particle size distribution are brought into a required state at the time of preparing the matting agent or by mixing a plurality of matting agents.

In the present invention, the matting agent is preferably contained in the outermost surface layer of the light-sensitive material, a layer functioning as the outermost surface layer, or a layer close to the outer surface, and in a layer acting as a so-called protective layer. It is preferably contained.

Suitable binders for the backing layer of the present invention are transparent or translucent, generally colorless, and include natural polymers such as synthetic resins, polymers and copolymers, and other film forming media such as: gelatin, gum arabic, poly (vinyl). Alcohol), hydroxyethyl cellulose,
Cellulose acetate, cellulose acetate butyrate, poly (vinylpyrrolidone), casein, starch,
Poly (acrylic acid), poly (methylmethacrylic acid), poly (vinyl chloride), poly (methacrylic acid), copoly (styrene-maleic anhydride), copoly (styrene-acrylonitrile), copoly (styrene-butadiene), poly ( Vinyl acetals (eg, poly (vinyl formal) and poly (vinyl butyral)), poly (esters), poly (urethane) s, phenoxy resins, poly (vinylidene chloride), poly (epoxides), poly (carbonates) ), Poly (vinyl acetate), cellulose esters, and poly (amide) s. The binder may be coated from water or an organic solvent or an emulsion.

In the present invention, the backing layer is 750 to 750.
The maximum absorption in the range of 1400 nm is preferably 0.3 or more and 2 or less, more preferably 0.5 or more and 2 or less, and the absorption in the visible region is 0.1.
It is preferably 001 or more and less than 0.5, and more preferably an antihalation layer having an optical density of 0.001 or more and less than 0.3.

When the antihalation dye is used in the present invention, the dye has a desired absorption in the range of 750 to 1400 nm, has a sufficiently small absorption in the visible region, and has a preferable absorbance spectrum shape of the backing layer. Any compound may be used as long as it is possible. For example, Japanese Patent Laid-Open No. 7-1329
5, compounds described in U.S. Pat. No. 5,380,635, JP-A-2-68539, page 13, lower left column, line 1 to page 14, lower left column, line 9, and 3-24539.
The compounds described in the lower left column on page 16 to the lower right column on page 16 can be mentioned, but the present invention is not limited thereto.

The preferred structure of the antihalation dye used in the present invention is shown below, but the present invention is not limited thereto.

[0042]

[Chemical 7]

[0043]

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The reducing agent for the organic silver salt may be any substance that reduces silver ions to metallic silver, preferably an organic substance. Conventional photographic developers such as phenidone, hydroquinone and catechol are useful, but hindered phenol reducing agents are preferred. The reducing agent is 1-10 of the emulsion layer.
It should be present as a percentage by weight. In multilayer constructions, if the reducing agent is added to a layer other than the emulsion layer, a slightly higher percentage, about 2 to 15%, tends to be more desirable.

In heat-developable photographic light-sensitive materials, a wide range of reducing agents have been disclosed, including amide oximes such as phenylamide oxime, 2-thienylamide oxime and p-phenoxyphenylamide oxime; An azine such as 3,5-dimethoxybenzaldehyde azine; a combination of an aliphatic carboxylic acid aryl hydrazide and ascorbic acid such as a combination of 2,2′-bis (hydroxymethyl) propionyl-β-phenylhydrazine and ascorbic acid; A combination of hydroxybenzene and hydroxylamine, reductone and / or hydrazine (eg hydroquinone and bis (ethoxyethyl) hydroxylamine, piperidinohexose reductone or formyl-4-methylphenylhydrazine. Combination etc.); hydroxamic acids such as phenyl hydroxamic acid, p- hydroxyphenyl hydroxamic acid and β- ants Nin hydroxamic acid;
A combination of azine and sulfonamide phenol (eg, phenothiazine and 2,6-dichloro-4-benzenesulfonamide phenol); α such as ethyl-α-cyano-2-methylphenylacetate and ethyl-α-cyanophenylacetate -Cyanophenylacetic acid derivative; 2,2'-dihydroxy-1,1'-binaphthyl,
6,6'-dibromo-2,2'-dihydroxy-1,
Bis-β-naphthol as exemplified by 1′-binaphthyl and bis (2-hydroxy-1-naphthyl) methane; bis-β-naphthol and 1,3-dihydroxybenzene derivatives (eg 2,4-dihydroxybenzophenone) Or a combination of 2 ', 4'-dihydroxyacetophenone); 5-pyrazolone such as 3-methyl-1-phenyl-5-pyrazolone; dimethylaminohexose reductone, anhydrodihydroaminohexose reductone and anhydrodihydro. Reductones as exemplified by piperidone hexose reductone; sulfonamide phenol reducing agents such as 2,6-dichloro-4-benzenesulfonamidophenol and p-benzenesulfonamidophenol; 2-phenylindane-1,
3-dione and the like; 2,2-dimethyl-7-t-butyl-
Chromanes such as 6-hydroxychroman; 1,4-dihydropyridines such as 2,6-dimethoxy-3,5-dicarboethoxy-1,4-dihydropyridine; 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) and 2,2-bis (Such as 3,5-dimethyl-4-hydroxyphenyl) propane); ascorbic acid derivatives (such as 1-ascorbyl palmitate and ascorbyl stearate); and aldehydes and ketones such as benzyl and biacetyl; 3-pyrazolidone and certain species. Indane-1,3-dione.

In addition to the components described above, it may be advantageous to include additives known as "toning agents" to improve the image. For example, the toning agent may be present in an amount of 0.1 to 10% by weight of the emulsion layer. Toning agents are described in US Pat.
Nos. 0,254, 3,847,612 and 4,123,282 are well known materials in the photographic art.

Examples of toning agents are phthalimide and N-hydroxyphthalimide; succinimide, pyrazoline-
5-one, and quinazolinone, 3-phenyl-2-
Cyclic imides such as pyrazolin-5-one, 1-phenylurazole, quinazoline and 2,4-thiazolidinedione; naphthalimide (eg N-hydroxy-
1,8-naphthalimide); cobalt complex (for example, cobalt hexamine trifluoroacetate); 3-mercapto-1,2,4-triazole, 2,4-dimercaptopyrimidine, 3-mercapto-4,5-diphenyl- Mercaptans exemplified by 1,2,4-triazole and 2,5-dimercapto-1,3,4-thiadiazole; N- (aminomethyl) aryldicarboximide, (for example, (N, N-dimethylaminomethyl)) Phthalimide and N, N- (dimethylaminomethyl) -naphthalene-2,3-dicarboximide); and blocked pyrazoles, isothiuronium derivatives and certain photobleaching agents (eg 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 derivative or metal salt, or 4- (1-naphthyl)
Phthalazinone, 6-chlorophthalazinone, 5,7-dimethoxyphthalazinone and 2,3-dihydro-1,4-
Derivatives such as phthalazinedione; phthalazinone and phthalic acid derivatives (eg, phthalic acid, 4-methylphthalic acid, 4
-Nitrophthalic acid and tetrachlorophthalic anhydride, etc.); Quinazolinedione, benzoxazine or naphthoxazine derivatives; Not only as toning agents but also as a source of halide ions for in situ silver halide formation Rhodium complexes such as ammonium hexachlororhodium (III), rhodium bromide, rhodium nitrate and potassium hexachlororhodium (III); inorganic peroxides and persulfates such as ammonium persulfate and hydrogen peroxide; 1 , 3-Benzoxazine-2,4-dione, 8-methyl-1,3-benzoxazine-2,4-dione and 6-nitro-
Benzoxazine-2,4-dione such as 1,3-benzoxazine-2,4-dione; pyrimidine and asymmetric-triazine (for example, 2,4-dihydroxypyrimidine, 2-hydroxy-4-aminopyrimidine and the like), Azauracil and tetraazapentalene derivatives (eg 3,6-dimercapto-1,4-diphenyl-1
H, 4H-2, 3a, 5, 6a-tetraazapentalene, and 1,4-di (o-chlorophenyl) -3,6
-Dimercapto-1H, 4H-2, 3a, 5,6a-tetraazapentalene, etc.).

The use of so-called stabilizers in the silver halide emulsions protects against the formation of additional fog and allows further stabilization against the loss of sensitivity during stock storage. Suitable antifoggants, stabilizers and stabilizer precursors which can be used alone or in combination are described in US Pat. Nos. 2,131,038 and 2,6
94,716, the thiazonium salts, U.S. Pat. Nos. 2,886,437 and Azaindene, U.S. Pat. Nos. 2,728,663, 2,444,605.
Mercury salts described in U.S. Pat. No. 3,287,135, urasols described in U.S. Pat. No. 3,287,135, sulfocatechols described in U.S. Pat. No. 3,235,652, oximes and nitrones described in British Patent No. 623,448, Nitroindazole, polyvalent metal salts described in US Pat. No. 2,839,405, thiuronium salts described in US Pat. No. 3,220,839, and US Pat. Nos. 2,566,263 and 2, 597, 915, palladium, platinum and gold salts, U.S. Pat. Nos. 4,108,665 and 4,
442, 202 halogen-substituted organic compounds,
U.S. Pat. Nos. 4,128,557 and 4,13
7, 079, 4, 138, 365 and 4,
459, 350 and the phosphorus compounds described in U.S. Pat. No. 4,411,985.

The emulsions of this invention include plasticizers and lubricants such as polyhydric alcohols (eg, glycerin and diols of the type described in US Pat. No. 2,960,404), US Pat. No. 2,588,765. No. and Id. 3, 1
The fatty acid or ester described in No. 21,060 and the silicone resin described in British Patent No. 955,061 may be included.

For the emulsion layer or the protective layer of the emulsion layer, matting agents such as starch, titanium dioxide, zinc oxide, silica, US Pat. Nos. 2,992,101 and 2,7.
Polymer beads such as beads of the type described in No. 01,245 may be included. The matt degree of the emulsion surface may be any value as long as no stardust failure occurs, but the Beck smoothness is preferably from 1,000 seconds to 10,000 seconds, particularly preferably from 2,000 seconds to 10,000 seconds.

The emulsions of the present invention include antistatic or conductive layers such as soluble salts (eg chlorides, nitrates, etc.),
Evaporated metal layers, ionic polymers such as those described in US Pat. Nos. 2,861,056 and 3,206,312 or insoluble inorganic salts such as those described in US Pat. No. 3,428,451. It can be used for a photographic light-sensitive material including a layer containing the same. The binder of the emulsion layer is selected from well-known natural or synthetic resins such as gelatin, polyvinyl acetal, polyvinyl chloride, polyvinyl acetate, cellulose acetate, polyolefin, polyester, polystyrene, polyacrylonitrile, and polycarbonate. be able to. Of course, copolymers and terpolymers are included in such definitions. Preferred binders are polyvinyl butyral, butyl ethyl cellulose, methacrylate copolymers, maleic anhydride ester copolymers, polystyrene and butadiene-styrene copolymers.

If desired, these polymers can be used in combination of two or more kinds. Such a polymer is used in an amount sufficient to hold the components therein. That is, it is used in an effective range to function as a binder. The effective range can be appropriately determined by those skilled in the art. As a guide at least for holding the organic silver salt, the ratio of the binder to the organic silver salt is:
The range of 15: 1 to 1: 2, particularly 8: 1 to 1: 1 is preferable. As the support used in the present invention, various ones can be used, but preferably, a polyester film, an undercoating polyester film, a poly (ethylene terephthalate) film, a polyethylene naphthalate, a cellulose nitrate film, a cellulose ester film,
Among the poly (vinyl acetal) films, polycarbonate films and related or resinous materials, as well as glass, paper, metals, etc., the most preferred support for embodiments of the invention is polyethylene terephthalate or polyethylene naphthalate. The support may be transparent or opaque, but is preferably transparent.

Backside resistive heating layers such as those shown in US Pat. Nos. 4,460,681 and 4,374,921 can also be used in photothermographic imaging systems. The photothermographic emulsion of the present invention may be dip coated, air knife coated, flow coated or as described in US Pat.
It can be coated by a variety of coating operations including extrusion coating using hoppers of the type described in 1,294. If desired, US Pat. No. 2,761,7
Two or more layers can be coated simultaneously by the method described in 91 and British Patent No. 837,095.

The present invention will be explained by the following examples, but the present invention is not limited to these examples.

[0055]

【Example】

Example 1 1-1. Preparation of silver behenate dispersions A to D 10% by weight of silver iodobromide (98 mol% Br, 2 mol%
I) a pre-prepared silver behenate complete soap (307 g) containing toluene (545 g), butanone (16 g).
34 g) and polyvinyl butyral (13.5 g) having an average molecular weight of 4000 were uniformly dispersed using a homogenizer. At this time, silver behenate dispersions A to D having average sizes shown in Table 1 were obtained by changing the dispersion time. The average size was determined by observing the silver behenate dispersion with an electron microscope and measuring the sizes of the minor axis and major axis of the 600 particles. The average size described below also uses the same evaluation method.

1-2. Preparation of Silver Behenate Dispersions E-H Same as Silver Behenate Dispersions A-D, but using silver halide-free pre-prepared complete soap, silver behenate dispersions having average sizes shown in Table 1. E to H were obtained.

[0057]

[Table 1]

1-3. Preparation of Emulsion Layer Coating Solution An emulsion layer coating solution was prepared according to the following formulation and coated on a polyethylene terephthalate support having a thickness of 175 μm, which was not undercoated, so that the coated silver amount was 2 g / m ² and then 4 minutes. Dried at 70 ° C .: Silver behenate dispersions A to D 100 g Silver behenate dispersions E to H 100 g (combinations of these dispersions are listed in Table 2) 2-butanone 50 ml Polyvinyl butyral (average molecular weight 4000) 30 g Pyridinium Hydrobromide Perbromide 0.2 g (in 3 ml MeOH) Lithium bromide (10% MeOH solution) 1 ml 2- (4-chlorobenzoyl) benzoic acid (12% MeOH solution) 10 ml 2-Mercaptobenzimidazole (1% MeOH solution) ) 10 ml Compound A 7 g

[0059]

Embedded image

The first six were mixed in this order at 25 ° C. under safe light conditions without blue light, left overnight at 10 ° C. and the rest was added at 25 ° C. Then, a dye 1 was added as a solution of 0.01% methanol / phenoxyethanol (1/1) mixed solvent under safelight conditions without IR light, and 5 × 10 ^{−4 was} added to silver halide to prepare a solution. Emulsion layer coating solutions 1 to 4 were used. In addition, emulsion layer coating solutions 5 and 6 were prepared in the same manner except that Dye 1 was not added.

1-4. Preparation of Coating Solution for Surface Protective Layer The following surface protective layer was applied on the emulsion layer in a wet thickness of 100 μm and dried for 4 minutes at 70 ° C .: Acetone 150 ml 2-Butanone 67 ml Methanol 30 ml Cellulose acetate 9.0 g Phthalazine 1 0.0 g 4-methylphthalic acid 0.7 g tetrachlorophthalic acid 0.6 g tetrachlorophthalic anhydride 0.65 g silicon oxide (particle size 2 μm) 0.5 g compound B 1.0 g

[0062]

Embedded image

1-5. Preparation of Backing Layer Coating Solution Prior to coating on the emulsion side, a backing layer was previously coated on a support. The contents of the coating liquid for the backing layer are listed below. Polyvinyl butyral (average molecular weight 4000) 6 g Butanone 69 g Methanol / butanone solution (50/50 w / w) 30 g Compound C 0.05 g

[0064]

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This solution was applied so that the absorption at 780 nm was 1.2 and dried at 75 ° C. for 4 minutes.

1-6. Preparation of Back Surface Protective Layer Coating Solution The following back surface protective layer was coated on the emulsion layer in a wet thickness of 100 μm and dried for 4 minutes at 70 ° C .: Acetone 140 ml 2-Butanone 70 ml Methanol 30 ml Cellulose acetate 9.0 g Polymethylmethacrylate 0.5g (Average particle size 10μm)

The emulsion layer coating solutions were combined as shown in Table 2 and the coatings of Examples 1-3 to 1-6 were carried out to give 5
Seed photographic materials 1-6 were prepared.

[0068]

[Table 2]

1-7. Evaluation of natural aging storability Each processed sample was left for 1 day under the condition of 25 ° C-50% RH, and 10 sheets of each photographic material were sealed in a bag made of moisture-proof material, and stored at 50 ° C for 5 days. Yes (forced aging).
For this photographic material containing photographic dye 1 (photographic materials 1 to 4), the same as that for forced aging except that the storage temperature was set to 4 ° C. for comparison, a laser sensitometer equipped with a 780 nm diode was used. The exposed photographic materials containing no dye 1 (photographic materials 5 and 6) were exposed to Xe light for 10 ⁻⁴ seconds through a 380 nm interference filter, and then processed (developed) at 120 ° C. for 15 seconds. The density of the fog portion of the obtained image was measured with a densitometer. The natural aging property was evaluated as a fog increase rate. (Fog increase rate) = [(fog of sample after forced aging)-(fog of comparative sample) / {(maximum density of comparative sample)-(concentration of support)} x 100 The lower the fog rate, the better the natural aging property. Is.

Table 3 shows the results of the above evaluations performed on the light-sensitive materials 1 to 6.

[0071]

[Table 3]

It can be seen that the storage stability over time is improved in the area of the present invention.

Example 2 2-1. Preparation of Backing Layer Coating Liquid First, a backing layer coating liquid was prepared with the following composition. Poly (vinyl alcohol) 256 g Deionized water 46 g Methanol 46 g Compound D 0.05 g Polymethylmethacrylate (average particle size 10 μm) 15.0 g

[0074]

[Chemical 12]

Poly (vinyl alcohol) (PVA) was added to the water with stirring. After raising the temperature to 80 ° C,
Mix for an additional 30 minutes. The temperature was reduced to 40 ° C. and methanol was added very slowly with maximum stirring.
The mixture was stirred for a further 30 minutes and then cooled to room temperature. This coating solution was applied so that the absorbance at 810 nm was 1.2.

2-2. Preparation of Organic Acid Silver Dispersions I to L 840 g of behenic acid and 95 g of stearic acid were added to 12 liters of water, and sodium hydroxide 4
A solution prepared by dissolving 8 g and 63 g of sodium carbonate in 1.5 liter of water was added. After stirring for 30 minutes, bring to 50 ° C.,
1.1 liter of 1% aqueous solution of N-bromosuccinimide was added, and then 2.3 liter of 17% aqueous solution of silver nitrate was gradually added with stirring. Further, the liquid temperature is set to 35 ° C.,
While stirring, 1.5 liter of a 2% aqueous solution of potassium bromide was added over 2 minutes and then stirred for 30 minutes, and 2.4 liter of a 1% aqueous solution of N-bromosuccinimide was added. While stirring this aqueous mixture, 1.2 wt% of an n-butyl acetate solution of polyvinyl acetate was gradually added to form flocs of the dispersion, and then water was removed, followed by washing with water twice and water removal. After that, polyvinyl butyral (average molecular weight 300
0) 2.5 wt% of butyl acetate and isopropyl alcohol in a 1: 2 mixed solution of 3.6 liters were added with stirring, and the gelled behenic acid / silver stearate and silver bromide thus obtained were added. 1125 g of polyvinyl butyral (average molecular weight 4000) and 5 liter of isopropyl alcohol were added to the mixture and dispersed. At this time, by changing the dispersion time, organic acid silver dispersions I to L having size distributions shown in Table 4 described below were obtained.

2-3. Preparation of Silver Halide Grain A 7.5 g of inert gelatin in 900 ml of water,
After dissolving 10 mg of potassium bromide and adjusting the temperature to 35 ° C. and pH to 3.0, an aqueous solution 370 containing 74 g of silver nitrate.
An aqueous solution of milliliters and potassium bromide was added to pAg 7.7.
Using the control double jet method while maintaining 10
It was added under a constant flow rate of silver nitrate per minute. After addition 4-
Hydroxy-6-methyl-1,3,3a, 7-tetrazaindene (0.3 g) was added, the pH was adjusted to 5 with sodium hydroxide, the average particle size was 0.06 μm, and the variation coefficient of the projected diameter area was 8%. , Cubic silver bromide grains having a [100] plane ratio of 87% were obtained. This emulsion was coagulated and sedimented using a gelatin coagulant and desalted, and then phenoxyethanol 0.1 g was added to adjust the pH to 5.9 and pAg to 7.5. After that, the temperature was set to 60 ° C., 1.3 mg of sodium thiosulfate, 0.4 mg of selenium compound I and 0.3 mg of tellurium compound were added, and after aging for 100 minutes, they were rapidly cooled and stored at 35 ° C. to obtain silver halide grains A. .

2-4. Preparation of Organic Acid Silver Dispersion M to P Behenic acid (63.6 g) was put into distilled water (1.8 liter) and dissolved by heating at 90 ° C. 1N sodium hydroxide (186.6 ml) was added with sufficient stirring, and the mixture was left as it was. It was left for 1 hour. Thereafter, the mixture was cooled to 30 ° C., 42 ml of 1N phosphoric acid was added, and 0.78 g of N-bromosuccinimide was added with sufficient stirring. Then, the above-described silver halide grains A were added with stirring while being heated to 40 ° C. so that the amount of silver was 10 mole% with respect to behenic acid. Further, 150 ml of 17% silver nitrate aqueous solution was continuously added over 2 minutes with vigorous stirring, and the mixture was left as it was for 1 hour. While stirring this water-based mixture, 1.2 g of an n-butyl acetate solution of polyvinyl acetate (1.2 wt% 222 g) was gradually added to form flocs of the dispersion, and then water was removed, followed by washing with water and removal of water twice. After that, polyvinyl butyral (average molecular weight 300
0) 2.5 g by weight of butyl acetate and isopropyl alcohol in a 1: 2 mixed solution (120 g) was added with stirring, and the gelled mixture of behenic acid and silver halide thus obtained was mixed with polyvinyl butyral (average molecular weight). 40
00) 75 g and isopropyl alcohol 342 g were added and dispersed. At this time, by changing the dispersion time, organic acid silver dispersions MP having the size distribution shown in Table 4 were obtained.

[0079]

[Table 4]

2-5. Preparation of Emulsion Layer Coating Solutions 7-18 Emulsion layer coating solutions 7-18 were prepared as follows using the organic acid silver dispersions I-P thus obtained. Organic silver salt dispersions I to P 462 g Dye 1 (same as in Example 1) 60 ml (0.065% dimethylformamide solution) Sodium p-methylphenylsulfinate 24 ml (0.01% methanol solution) Phtharazinone 4.32 g Compound A (same as in Example 1) 8.4 g In addition, the coating liquids 15 to 18 do not include the dye 1. Coating solutions 7 to 18 were coated so that the amount of silver was 2 g / m ² .

A 10% acetone solution of cellulose acetate was used for the surface protective layer of the emulsion layer. Dry thickness 2 μm
It applied so that it might become. Thus, the photographic material 7 shown in Table 5
~ 18 were obtained.

[0082]

[Table 5]

Photographic material containing Dye 1 (Photographic material 7
14 to 14) were exposed with a laser sensitometer equipped with an 810 nm diode, and photographic materials containing no dye 1 (photographic materials 15 to 18) were exposed to Xe light for 10 ⁻⁴ seconds through an interference filter of 380 nm. Table 6 shows the results of the same evaluations as in Example 1 except for the above.

[0084]

[Table 6]

It can be seen that in the area of the present invention, the storage stability over time is improved.

[0086]

INDUSTRIAL APPLICABILITY According to the present invention, even a photothermographic material which has been subjected to infrared spectral sensitization has excellent storage stability.

Claims (2)

[Claims] 1. A photothermographic material containing photosensitive silver halide grains spectrally sensitized in the range of 750 to 1400 nm and a non-photosensitive silver salt, wherein the non-photosensitive silver salt grains have major and minor axes. Needle-like crystals having the average major axis size of the needle-like crystal particles of the non-photosensitive silver salt of 0.10 μm or more and 5 μm or less,
A photothermographic material having an average minor axis size of 0.01 μm or more and 0.20 μm or less. 2. The photothermographic material according to claim 1, wherein the non-photosensitive silver salt is a silver salt of a fatty acid.