JPH01221737A - Silver halide photographic emulsion - Google Patents

Abstract

PURPOSE:To improve preservability of a silver halide photographic emulsion under natural conditions by incorporating a combination of a sensitizing dye having a maximum spectral sensitivity at >=700nm wavelength region with at least one precursor of an N-contg. heterocyclic compd. having a mercapto group into the emulsion. CONSTITUTION:A precursor to be used is a precursor of an N-contg. heterocyclic compd. having a mercapto group which liberates an N-contg. heterocyclic compd. having a mercapto group by being hydrolyzed by an alkali in a developing soln. Said compd. is added to a silver halide emulsion sensitized spectrally with a sensitizing dye having a maximum spectral sensitivity in a >=700nm wavelength region. Thus, the preservability of a photosensitive material prepd. from this emulsion is remarkably improved as compared to emulsions contg. a conventional stabilizer such as 1-phenyl-5-mercapto tetrazole, etc.

Description

Detailed Description of the Invention (A) Industrial Application Field The present invention relates to a spectrally sensitized silver halide photographic emulsion, and particularly to a silver halide photographic emulsion with improved storage stability in the infrared spectral region. It is something.

CB) Prior art and its problems Depending on the purpose of use, silver halide photographic materials are
They are required to have high sensitivity at different specific wavelengths.

It is generally well known that, as one of the techniques for producing light-sensitive materials, certain sensitizing dyes are added to silver halide emulsions to effectively increase the sensitivity in a specific wavelength range.

On the other hand, with the rapid development of optoelectronics in recent years, light sources such as laser light and LED light have begun to be used in place of conventional incandescent light bulbs and the like as light sources for outputting digitized image information. He-N is already in practical use.
Examples include e-laser, argon laser, red LED, and semiconductor laser light. Among these, semiconductor lasers have the advantages of being inexpensive, easy to modulate, and long-life, and their future is considered promising. Semiconductor lasers include Ga/As/P; Ga/At/As; Ga/As;
;'Ln/P: A semiconductor of the Ln/A s type is used, and the wavelength of this laser light is generally longer than 700 nm, and in particular, is often longer than 750 nm.

In order to produce silver halide emulsions suitable for exposure with these semiconductor laser beams, when spectral sensitization is performed using a sensitizing dye, infrared sensitization cannot be achieved using conventional methods. If a photosensitive material coated with such an emulsion is stored at room temperature, it becomes severely desensitized and becomes unusable, so it was necessary to refrigerate or freeze the photosensitive material to preserve it. However, it is very inconvenient to keep the infrared light-sensitive material refrigerated or frozen after it is manufactured until it is used, which requires time and effort to manage and is costly. For this reason, there is a strong desire for an infrared light-sensitive material that exhibits less decrease in sensitivity and less increase in capri even when stored at room temperature.

By the way, the present inventors have determined that infrared light-sensitive materials are stored at 50°C, which is known as a storage test method for silver halide photographic light-sensitive materials.
It was confirmed that even if storage under forced conditions such as 80% relative humidity (RH) tends to increase sensitization, storage under natural conditions results in desensitization, which does not match. Mercapto compounds such as 1-phenyl-5-mercaptotetrazole cannot be said to be effective in improving the storage stability of such infrared light-sensitive materials.

(C) Object of the Invention An object of the present invention is to provide an infrared-sensitive silver halide photographic emulsion with wavelengths longer than 700 nm that has excellent storage stability under natural conditions.

CD) Structure of the Invention The above object can be achieved by using a combination of at least one sensitizing dye having maximum spectral sensitivity in a wavelength region of 700 nm or more and at least one precursor of a nitrogen-containing heterocyclic compound having a mercapto group. was achieved.

The precursor of the nitrogen-containing heterocyclic compound having a mercapto group is a compound that is hydrolyzed by an alkali in a developer to liberate a nitrogen-containing heterocyclic compound having a mercapto group.

Examples of nitrogen-containing heterocyclic compounds having a mercapto group include U.S. Pat. No. 2,981,624 and U.S. Pat.
No. 7, No. 3,674,478, JP-A-57-765
No. 41, No. 57-135944, No. 135-1982
No. 945, No. 57-136640, No. 61-19 No. 1983
No. 6239, No. 196240, No. 61-8, No. 61-8
Compounds described in No. 3532 and the like can be used.

Specific examples of the precursor of the nitrogen-containing heterocyclic compound having a mercapto group used in the present invention include the above-mentioned compounds, and the present invention is not limited thereto.

These compounds may be added at any stage during the preparation of a silver halide photographic emulsion, but it is preferable to add them as additives after chemical ripening is completed. The amount of these compounds added is usually 5 to 5 per mole of silver halide.
00η, preferably 10 to 300■.

When these compounds f are added to a silver halide emulsion spectrally sensitized with a sensitizing dye having a maximum spectral sensitivity at a long wavelength of 700 nm or longer, the storage stability of a photographic material using this emulsion is affected by a stabilizer known as a stabilizer. This is markedly improved compared to the case where, for example, 1-phenyl-5-mercaptotetrazole is used.

These compounds can be used in layers other than the silver halide photographic emulsion layer,
For example, the same effect can be obtained even if it is contained in a protective layer, intermediate layer, undercoat layer, etc. and diffused into the emulsion layer. However, in this case, it is necessary to use a slightly larger amount of i-w than if it were added directly to the emulsion layer.

The sensitizing dye used in the present invention and having maximum spectral sensitivity in a wavelength region longer than 700 nm is disclosed in, for example, U.S. Patent No. 2.
No. 095,854, No. 2,095,856, No. 2
, No. 955,939, No. 3,482,978, No. 3.55 974, No. 3.57 No. 921, No. 3
, No. 582,344, No. 3,623,881, and the like.

Preferably, for example, dyes represented by the following general formulas (1) to (IV) are used.

- In general formulas (I) to (IV), 2. and Z2 may be the same or different, and each has 5 or 6 members.
Represents the atomic group necessary to form a nitrogen-containing heterocycle.

R1 and R2 may be the same or different and each represents an alkyl group or an alkenyl group. RJ3 is
Represents an alkyl group, alkenyl group, or aryl group. R4
-R10 may be the same or different, and each represents a hydrogen atom, a /%rogen atom, an alkyl group, an aryl group, or an alkoxy group. However, R6 and R7 or R
8 and R9 can also be linked to each other to form a 5- or 6-membered ring. R11 and R12 may be the same or different, each representing an alkyl group or an aryl group, and R11 and R12 may be linked to each other to form a 5- or 6-membered ring. Y is a sulfur atom, an oxygen atom 1.
NR+1x (Rlg is an alkyl group).

X represents an acid anion. 7. m, n, p and q each represent 1 or 2.

Specific examples of zl and z2 include thiazole, benzothiazole, naphtho[1,2-α]thiazole, naphtho(
:2.1-a) Thiazole, naphtho (:2.3-α)
Thiazole, selenazole, benzoselenazole, naphtho[1,2-α] C2,1-α] selenazole, naphtho[1,2-α
] Selenazole, oxazole, benzoxazole,
naf) [1,2-α]oxazole, nut [2,1
-α]oxazole, Nando[2゜3-α]oxazole, 2-quinoline, 4-quinoline, 3,3-dialkylindolenine, imidazole, benzimidazole, naph) [1,2-α]imidazole, pyridine, etc. Mention may be made of nitrogen-containing heterocycles. These heterocycles include alkyl groups (e.g., methyl, ethyl, butyl, trifluoromethyl, etc.), aryl groups (e.g., phenyl, tolyl, etc.), hydroxy groups, alkoxy groups (e.g., methoxy, ethoxy, butoxy, etc.), Carboxy groups, alkoxycarbonyl groups (e.g. methoxycarbonyl, ethoxycarbonyl), halogen atoms (e.g. fluorine, chlorine, bromine, iodine), aralkyl groups (e.g. benzyl, 2
enethyl, etc.), a cyano group, and an alkenyl group (eg, allyl).

In R1+ "2, the alkyl group includes lower alkyl groups such as methyl, ethyl, propyl, butyl, hydroxyalkyl groups such as β-hydroxyethyl and γ-hydroxypropyl, β-methoxyethyl, γ-methoxypropyl, etc. , alkoxyalkyl groups such as β-acetoxyethyl, γ-acetoxypropyl, β-benzoyloxyethyl, carboxymethyl, β
-Carboxyalkyl groups such as carboxyethyl, methoxycarbonylmethyl, ethoxycarbonylmethyl, β-
Flucoxycarbonyl alkyl groups such as ethoxycarbonylethyl, β-sulfoethyl, γ-sulfopropyl,
Examples of the alkenyl group include sulfoalkyl groups such as -sulfobutyl, aralkyl groups such as benzyl, phenethyl, and sulfobenzyl, and allyl.

Examples of R3 include the alkyl groups and alkenyl groups mentioned above for R1 and R2, as well as aryl groups such as phenyl, tolyl, methoxyphenyl, chlorophenyl, and naphthyl.

R10 to R4 is a hydrogen atom, a halogen atom (e.g. chlorine, bromine, iodine, fluorine), an alkyl group as described in R1m "2, an aryl group, or an alkoxy group having a higher alkyl as described in R1* R2 (i.e. OR1 group), and the 5-negative or 6-membered ring formed by R6 and R7 or R8 and R9 may be substituted with a lower alkyl group, etc. R11 and R12 are "1 s 'FL2
represents an alkyl group or an aryl group as described above, and R1
1 and R12 can also be linked to each other to form a 5- or 6-membered ring. Examples of R111 include the alkyl groups described for R, and R2.

Examples of the acid anion of It doesn't exist if you take it.

Specific examples of the sensitizing dye used in the present invention are illustrated below.

■ S.O.

5O5- Tortoise2H5 ■- ni2ti5'-;2f1580゜nee5(J5 ■- 2H5 ■- (CH2)4 O3 Crystal S ■- CH8+5Os- The sensitizing dye used in the present invention can be prepared by a method known to those skilled in the art. The amount of the sensitizing dye added is from 1 mole of silver halide to 5XIQ-' mole, preferably tt,
< is in the range of 5×10 mol to 1×10 mol.

These sensitizing dyes can be dispersed directly in the emulsion or dissolved in a water-miscible solvent such as methanol, ethanol, pyridine, methylselonulp, acetone, dimethylformamide, etc. (or a mixture thereof) and In some cases it can be diluted with water, and in other cases it can be dissolved in water and added to the emulsion in the form of these solutions.

Ultrasonic vibrations can be applied to this dye solution, and US Pat.
It can also be added by the method described in 5. In addition, U.S. Patent No. 2
, No. 912,345, No. 3,342,605, No. 2,
The methods described in No. 996,287, No. 3,425,835, etc. can also be used.

The sensitizing dye may be used alone or in combination of two or more, and may contain other dyes.

The sensitizing dye may be added at any time from the production of the silver halide photographic emulsion to its coating.

Silver halides used in the present invention include silver chloride, silver chlorobromide,
Silver iodobromide, silver chloroiodobromide, etc. may be used.

The silver halide may have any shape, and any known method for producing it may be used. For example, precipitation may be performed by a method such as an ammonia method, a neutral method, an acid method, or a partial ammonia method that is a mixture of a neutral method and an ammonia method. Further, any mixing method such as forward mixing, back mixing, or simultaneous mixing may be used, and in particular, a simultaneous mixing method called the so-called double jet method in which the crystal habit is controlled under the control of PAg can also be applied. Furthermore, it can also be applied to conversion methods that utilize differences in solubility.

For example, the conversion method type emulsion manufacturing method is described in U.S. Patent No. 2.59.
No. 2,250. Furthermore, J.

phot, sci, 2139-50 (1973),
Also included are emulsions precipitated in the presence of crystal 1iJ'JA stabilizers as described in et al.

During precipitation or physical ripening of silver halide, metals such as iridium and rhodium can also be used.

These emulsions can be subjected to chemical ripening by known methods. Namely, U.S. Patent No. 1,574,944, U.S. Patent No. 2,
No. 278,947, No. 2,410,689, No. 3.1
Sulfur sensitization can be performed using a sulfur compound or a sensitized gelatin containing a sulfur compound as described in No. 89,458 and No. 3,501,313. Gold sensitization using gold compounds described in US Pat. No. 2,597,856, US Pat. No. 2,597.915, US Pat.

Also, U.S. Patent Nos. 2,518,698 and 2,521,9
Reduction sensitization can also be carried out as described in Nos. 25, 2487850 and 2694637. These sensitization methods can be used not only alone but also in combination.

The photographic emulsion used in the present invention can also be sensitized using quaternary ammonium salts, thioether compounds, polyethylene oxide derivatives, diketones, and the like. These methods are described in U.S. Pat.
No. 046,132, No. 3,046.133, No. 3,0
No. 46,134, No. 3,046,135, British Patent No. 939,357, etc.

As the binder or decoy for the photographic emulsion and non-photosensitive layer used in the present invention, lime-treated or acid-treated gelatin, gelatin derivatives such as phthalated gelatin, and polyvinyl alcohol are mainly used, and polyvinylpyrrolidone, polyvinylpyrrolidone, Acrylic water-soluble copolymers, starch and its derivatives, polysaccharides such as cellulose derivatives, etc. can be used in combination. It is also possible to modify the physical properties of the gelatin film by adding latex polymers, or to make the film surface matte by adding silica, starch powder, rhoidal silica, glass powder, etc.

The photographic emulsion and non-light-sensitive layer of the present invention may contain coating aids, ie, surfactants for lowering the surface tension and improving the wetting effect.

Effective coating aids include saponin, nonionic surfactants such as alkylene oxide, glycerin, and glycidol, and higher alkylamines.

Quaternary ammonium salts, pyridine and other heterocycles,
Cationic surfactants such as sulfoniums.

Examples include anionic surfactants containing acidic groups such as carboxylic acids, sulfonic acids, phosphoric acids, sulfuric ester salts, and phosphoric ester groups, and amphoteric surfactants such as amino acids, aminosulfonic acids, and esters of amino alcohols. , and also Japanese Patent Publication No. 47-9303, U.S. Patent No. 3,589,906
No. 1.961638, West German Patent Publication No. 212426
Also included are fluorinated surfactants described in No. 2 and the like.

The silver halide photographic light-sensitive material of the present invention includes known anti-capri agents, hardeners, antistatic agents, developing agents, slipping agents, optical brighteners, anti-irradiation dyes, anti-irradiation dyes, It can optionally contain dyes to improve safelight safety.

The supports on which the emulsions according to the invention are coated are particularly limited. That is, it can be applied to film bases such as polyester films and cellulose triacetate films, paper pastes such as baryta paper, resin-treated paper, and synthetic paper, or supports such as dry plate glass and metal plates.

(Fli) Examples Examples will be shown below to specifically explain the present invention, but the present invention is not limited thereto and can be applied in various ways within the scope of the claims.

Example 1 An emulsion was prepared according to the following recipe.

The liquid (2) was kept at 40°C, and the liquid (2) was added thereto under vigorous stirring. After aging at 40° C. for 30 minutes, the pH was lowered to 6.0, gelatin 1002 was added and dissolved, and the mixture was cooled, solidified, shredded, and washed with water to desalinate. Each emulsion prepared in this way was
After dissolving at 0°C and adjusting the pH to 6.5 and pAg to 8.9, 40 μ of sodium thiosulfate per mole of silver halide and 15 μ of anthonium gold thiocyanate per mole of silver halide were added, and the mixture was heated at 55°C and 60 μm. Chemical ripening was performed for 1 minute.

After dividing this emulsion into several parts and adding a sensitizing dye and a precursor of a nitrogen-containing heterocyclic compound having a mercapto group as shown in Table 1, a coating aid and a hardening agent were added, and then polyethylene was laminated. A sample was obtained by coating on a 100 μm paper support and drying. The amount of silver coated was 1.8 f/d.

Divide these samples into 4 parts and heat each one at 50℃8.
096RH After storage for 5 days ■ After storage for 1 month at 35° C. and 80% R and H ■ After 12 months of natural storage Exposure and development was carried out in the following manner.

Exposure, development, and measurement of the sample were performed in the following manner.

The sample was exposed to light using a photosensitive needle having a light source with a color temperature of 5,400°, and a dark red filter was attached to the light source to emit light with a wavelength longer than 700 nm. Subsequently, each sample was developed using D-72 developer at 20 DEG C. for 90 seconds, stopped, fixed, and washed with water to obtain strips with a predetermined black and white image.

Macbeth of the United States iMAcBBTHTD-
The concentration was measured using a 504 densitometer to obtain the infrared light sensitivity.

The optical density reference points used to determine sensitivity are all at a density of 0.
The score was 75.

The results obtained are shown in Table 1.

As is clear from Table 1, the sensitivity after storage at 50°C, 80% RH for 5 days is higher than the sensitivity immediately after application for all samples, but after storage at 35°C, 80% R for 1 month, and natural storage. 1
Regarding the relative sensitivity after 2 months, the ratio 42 sample 4.5 was desensitized, whereas the present inventions 1 to 3 showed almost no desensitization.

Example 2 An emulsion was prepared according to the following formulation.

Keeping Solution V at 60°C, add Solution (2) and Solution (2) simultaneously over 30 minutes with strong stirring, and the pAg during this time was 7.4.
was controlled. Then add ■ solution and pn = a, s
The solution was precipitated and washed with water.

This raw emulsion is a silver iodobromide emulsion containing 97.5 mol of bromide, and has an average grain size of 0.25μ, a cubic monomer containing grains within ±20% of the average grain size and 95% by weight or more. It is a dispersed emulsion.

This raw emulsion was redissolved, gelatin was added, and the pH was adjusted to 6.5.
Then, 4 (19 parts) of sodium thiosulfate per mol of silver halide and 15 parts of ammonium gold thiocyanate per 1 mol of silver halide were added, and chemical ripening was carried out at 55°C for 60 minutes.

This emulsion was divided into several parts, and after adding a sensitizing dye and a precursor of a nitrogen-containing heterocyclic compound having all mercapto groups as shown in Table 2, a coating aid and a hardening agent were added, and then a polyethylene terephthalate film was added. Apply and dry.

Is the amount of silver applied 3.0f/lr? Met. Each sample thus prepared was treated in the same manner as in Example 1. Table 2 shows the sensitivity (relative value) obtained as a result of the transmission density measurement. The reference point for the transmission density at which the sensitivity was determined was a point with a density of 3.0.

Table 2 As is clear from Table 2, comparative samples 21 and 22 were heated at 35°C.
While the relative sensitivity after storage at 80% RHL Yugetsu was significantly desensitized, Inventions 1 to 20 showed almost no desensitization.

Claims (1)

[Claims] (1) A silver halide characterized by containing a combination of at least one sensitizing dye having maximum spectral sensitivity in a wavelength region of 700 nm or more and at least one precursor of a nitrogen-containing heterocyclic compound having a mercapto group. Photographic emulsion.