JPS61196240A - Silver halide photographic sensitive material - Google Patents

Abstract

PURPOSE:To form a fog inhibitor capable of preventing fog due to overdevelopment and extremely small in loss of photosensitivity by incorporating a specified compd. in a silver halide emulsion layer and/or a colloidal layer having water permeability relation between this layer and said emulsion layer. CONSTITUTION:The fog inhibitor to be added is a thioether type fog inhibitor precursor, a sufficiently stable in a weak acid medium, extremely effective against over-development fogging, and further, extremely small in deterioration of sensitivity, and it is represented by formula (I) and (II) in which A is the heterocyclic group of the mercapto fog inhibitor. As the inhibitor, any compd. having a fog preventive effect may be used, and compds. each having an N-cong. 5- or 6-membered hetero ring having an S atom combined with the C atom adjacent to the N atom of said ring are especially preferable, and such a ring can be typified by tetrazole, etc., rings.

Description

Detailed Description of the Invention (4) Field of Industrial Application The present invention relates to a photographic material containing a silver halide emulsion layer that is stabilized against overdevelopment fog. Technology and its Problems Silver halide photographic materials can be processed in a very short period of time under strong conditions, for example, by developing at relatively high temperatures or using highly active developer solutions (development with high temperature and high pH). In the case of a time development process, there is a risk that silver halide grains having no latent image nuclei may also be reduced.

The capri formed by the undesired reduction of unexposed silver halide grains under the above conditions appears particularly strongly at the end of the normal development G1 process, and is called overdeveloped capri. Anti-capri agents that are known to be effective against anti-fogging agents include mercury compounds and heterocyclic mercapto compounds. These anti-foggants usually reduce capri during the first stage of development and even during over-development. However, when added in an amount sufficient to reduce the capri, it also has the disadvantage of considerably reducing the sensitivity of the silver halide photographic material.

A fundamental disadvantage of adding compounds such as compound X#1 formula melucato compounds, which themselves are particularly active against overdevelopment fog, directly to silver halide emulsions is that they are completely active from the point of addition. This means that it is already fully active during the manufacturing process, during the storage period of the photographic material, and at the stage of development. This results in a desensitizing effect.

In order to solve this problem, the mercapto groups of these compounds are protected with suitable hydrolyzable groups, so that they remain inactive during the period when their effects are not desired (the entire period before development, including the manufacturing process). Attempts have already been made to regenerate these active forms by hydrolysis with alkali during the development process. Such substituents are usually thioesters or thioethers of the mercaptocapric inhibitor.

Thioester type substituents include carboxylic acid, sulfonic acid,
Thioesters of carbonic acid derivatives are disclosed in many patents, such as German Patent No. 1,597,503, U.S. Pat.
, 260,597 and German Patent Application No. 2.061,972 ◎ However, these thioesters are hydrolyzed in the alkaline medium A of the developer, but are not neutral or weakly hydrolyzed. It has the disadvantage that partial hydrolysis proceeds gradually even in an acidic pH range.Thus, these thioester-type anticapri agents can be added to emulsions in an inactive form, but they cannot be added to the emulsion during the emulsion preparation process. In addition, if the storage period of the photographic material is sufficiently long, partial hydrolysis may cause undesirable desensitization effects.

In contrast, antifoggants having thioether substituents, such as those described in U.S. Pat. No. 2,981,624, U.S. Pat.
Although the compound disclosed in No. 173,796 is indeed stable in neutral or weakly acidic media, it does not regenerate the original mercaptocaprylic agent at all during the development process, or only very gradually. Because it does not regenerate, overdevelopment capri cannot be effectively prevented. Compounds that can release mercaptocapri inhibitors do release the antifoggant quickly in the presence of alkali and are effective against overdevelopment fog, but they are somewhat unstable in weakly acidic media and gradually Therefore, if the time after emulsion preparation (emulsion pH is weakly acidic) and coating is sufficient, the antifoggant may be released into the emulsion. This results in an undesirable noodle texture.

Furthermore, even if the core compound is added to the emulsion in its complete form, there is a slight increase in sensitivity when compared to the sensitivity when an active mercaptocapri inhibitor is added, but when no capri inhibitor is added. Compared to the sensitivity obtained in this case, the fist results in a considerable loss of sensitivity.

According to [, it makes only a very small contribution to increasing the sensitivity of silver halide photographic light-sensitive materials◎(υ Purpose of the present invention The purpose of the present invention is to avoid firing in a neutral or weakly acidic pH region. ,
It is completely stable, but in the alkaline PI region (during development), it releases an active anti-capri agent to the desired degree, thereby preventing over-development fog and having extremely low loss of sensitivity. An object of the present invention is to provide an antifoggant (hereinafter referred to as an antifoggant precursor).

(D) Structure of the present invention The inventors of the present invention have intensively investigated the above problems and discovered that a thioether type antifoggant precursor represented by the following general formula (1) or a surface optically satisfies the above conditions. did.

In particular, we have discovered an unexpectedly effective antifoggant precursor from US Pat. No. 3,674,478.

That is, the precursor of the present invention is sufficiently stable even in a weakly acidic medium, is extremely effective against overdevelopment capri, and has extremely low sensitivity loss (compared to the case where no antifoggant is added). It is a completely new compound that cannot be easily deduced from the above patent.

General formula (1) 0) i-R.

8-M general formula (II) [In the formula, M represents a bivalent group of a mercapto antifoggant, R is a hydrogen atom, alkyl 4 (preferably a carbon number of 1
~10 alkyl groups) or phenyl groups, 11%
R1 is a hydrogen atom, an alkyl group (preferably a carbon number of 1 to
R1 represents a water-based atom, an alkyl group (preferably a substituted or unsubstituted alkyl group with 1 carbon number) or an aryl group, but neither R1 nor R1 is a water
~10 alkyl group), or a phenyl group, R4
, R55R represents a hydrogen atom, a nohalogen atom, an alkyl group (preferably an alkyl group having 1 to 10 carbon atoms), or a phenyl group, and in the case of general formula (1), FiRa and R@
, in the case of general formula (II), R4 and R, or R, and R- may be bonded to each other to form a benzene ring. ] The mercapto antifoggant may be any compound as long as it has an antifogging effect; preferable.

Typical examples of heterocycles include tetrazole tumulus, 1,
2.4-) lyazole ring, pentuoxazole loam, pentuthiazole rinsing, penzimidazole loam, pyridine loam,
Examples include pyrimidine rings.

Examples of typical anti-capri agent precursors according to the present invention which correspond to the above general formula (1) are listed below, but the compounds of the present invention are not limited thereto. Table I shows the general formula (1). Compounds corresponding to the following are shown in Table ■ with the general formula (
Compounds corresponding to II) are shown below.

Synthesis examples of typical antifoggant precursors of the present invention are shown below.

Synthesis Example 1> [Synthesis of Exemplary Compound ω] B) Intermediate: 1-phenyl-5-(3-formyl-4-
Synthesis of hydroxybenzylthio)tetrazole.

5-chloromethylsalicylaldehyde 25.6N and 1-
Phenyl-5-mercaptotetrazole 26.7jt-
After dissolving in dioxane 250111, bring the internal temperature to 20°C with ice water.
℃ or less, and while stirring, add triethylamine 20.
Drop 8dt.

After dropping, stir at room temperature for 2 hours. After the reaction, the precipitated salt was removed and concentrated under reduced pressure. Dry.

After drying, it was separated from sodium sulfate, distilled under reduced pressure, and recrystallized from a mixed solvent of ethyl acetate and cyclohexane. Yield: 37.2 J' Melting point: 121-122°C (→
Synthesis of Exemplary Compound (1) 5.41JI of 7-elhydrazine and 100d of ethanol
was added, and while cooling with ice water and stirring, 15.6F of 1-phenyl-5-(3-formyl-4-hydroxybenzylthio)tetrazole obtained in step (vi) above was added, and the mixture was stirred for 2 hours.

The precipitated crystals were collected in a furnace, washed with ethanol, and then recrystallized in benzene to obtain exemplified compound (1) t''.Yield:
1&91F Melting point: 174.5-176.0℃ Elemental analysis calculation value 0:62.67% H: 4.51% N: 2
0.88% measurement value 0:62.60% H:4.65%
N: 20.81% Other antifoggant precursors can be easily synthesized in substantially the same manner as described in Synthesis Example (1).

The anti-capri precursor used according to the invention can be added to the silver halide emulsion layer of the photographic light-sensitive material or to a colloid layer in water-permeable relationship with the emulsion layer, such as an overcoat or subbing layer for the emulsion layer. The anti-capri precursor of the present invention is dissolved in a solvent that is miscible with water, such as DMF, methanol, ethanol, etc., and added to and mixed with the silver halide emulsion or colloidal dispersion before coating. It can be added to the above-mentioned silver halide emulsion or the above-mentioned colloidal dispersion.Furthermore, the anti-capri agent precursor of the present invention is dispersed in latex using a method as shown in JP-A-53-137131. When the anticaprilant precursor according to the present invention, which can also be cooled into the silver halide emulsion or the colloidal dispersion described above, is mixed into the silver halide emulsion A, a solution of the precursor is added at any step of the emulsion preparation. However, it is preferable to add it just before the * side of the emulsion.

The anti-capri precursor 11172 according to the present invention varies depending on the type of compound and the position of the compound in the photographic light-sensitive material.
In terms of moles, the amount of anti-capri precursor according to the invention is preferably between 11 and 100 mmol.
io, s~50 mmol is preferable.

It can be used at a slightly higher concentration when it is added in another colloid layer that comes into contact with or comes into contact with the silver halide emulsion layer during development. ◎The photographic light-sensitive material developed according to the present invention can be stabilized using a conventional fixing or stabilizing solution.〇The silver halide emulsion that can be used in the present invention may be any type of emulsion. For example, they may be spectrally sensitized and non-sensitized emulsions, Alternatively, it may be made from Vanchrome.

As the photosensitive silver salt, various silver salts can be used. For example, silver bromide, silver iodide, silver chloride, or mixed silver halide (J
3 [Silver bromide, silver iodobromide, etc.] @Silver halide,
Common hydrophilic colloids, such as gelatin, azein,
It can be dispersed in polyvinyl alcohol, carboxymethylcellulose, etc., but gelatin is advantageous.

Silver halide emulsions can be sensitized both chemically and optically by ripening in the presence of small amounts of sulfur-containing compounds (e.g. allyl thiocyanate, allyl thiourea, sodium thiosulfate, etc.). can be sensitized to

The emulsion may also contain a reducing agent C, for example French Patent No. 1,1
No. 46,955, U.S. Patent No. 2.487°850
tin compounds as described in British Patent No. 789.823;
Aminomethanesulfine II! compounds) and small amounts of noble metals such as gold, platinum, palladium, iridium, ruthenium-1, and rhodium.

-They can also be optically sensitized by cyanine dyes and merocyanine dyes.Other additives, such as development accelerators, sensitizers, antioxidants, etc. can also be added to the silver halide emulsion layer or other water-permeable colloids. Can be added to layers.

Furthermore, the anticapri precursors according to the invention can be used in combination with other anticapri agents or other anticapri precursors.

Hereinafter, the present invention will be explained in detail with reference to Examples〇(I9〈
Example 1> Composition of silver bromide 65.5 mol%, silver chloride 34.0 mol%, silver iodide 0.5 mol%, average grain size 0.45 part m
A silver iodobromide gelatin emulsion of The emulsion was finished by adding dyes, stabilizers, surfactants, and hardeners.

The resulting gelatin-silver halide emulsion was divided into t-24 parts, and the above-mentioned anticaprilant precursor exemplified compound was added to each of 1 to 18s at a concentration of 2 mmol for silver halide l-G-nyl, and to the remaining 3 parts. For comparison, l-phenyl-5-mercaptotetrazole (comparison), 2-mercaptobenzthiazole (ratio [B), and 2-mercaptobenzimidazole (ratio ffo)' were each silver halide 1
It was added at a concentration of 2 mmol per mole.

In two further parts, each of the following anti-capri precursors disclosed in U.S. Pat. No. 3,674,478 (Comp. D, Comp. Added in concentration.

Furthermore, I did not add any questions to the other part. (Comparison F) These anti-capri agent precursors (or anti-capri agents) were added immediately before coating ◎ The resulting 24 emulsions were applied as silver nitrate to a photographic base coated with polyethylene layers on both sides. s pyrre,
The gelatin was coated at a ratio of 6.01/rn'' and dried.

The obtained sample was heated at 50°C for 1 day. A portion of each sample was exposed through a stepped light wedge, developed for 90 seconds at 20° C. using a developer having the composition shown below, stopped, fixed, washed with water, and dried to determine photographic properties.

Developer solution> Water 750d
Metol 1.0jl Hydroquinone 4. OJF Sodium Sulfite 15. OA + Sodium carbonate (l hydrate) 26.71 Potassium bromide
Add 0.7jl water
1,000dpH adjusted to 10.5 ◎ Next, another part of each sample was treated with the above developer for 30 minutes without exposure.
Developed at 0°C for 6 minutes, then developed another part of each sample by raising the pH of the developer to 12.0 without exposing it, and developing another part of each sample without exposing it to the developer solution. pHt-1
3. I raised the image to OK, developed it, and examined the capri. The results obtained are shown in Table I.

(Left below) <Example 2> After chemically sensitizing a silver iodochlorobromide gelatin emulsion prepared in the same manner as in Example 1, a sensitizing dye, a stabilizer, a surfactant, and a hardening agent were added. The emulsion was finished.

The resulting gelatin-silver halide emulsion was divided into 101 flS, and the above-mentioned anti-capri precursor exemplified compound was added to each of 1 to 7 parts at a concentration of 2 mmol per mol of silver halide.

For comparison, one part of the remainder contained 1-phenyl-5-mercaptotetrazole (comparison), and another part contained the following caprylate as disclosed in U.S. Pat. No. 3,674,478. Inhibitor precursors (comparison B) were added at a concentration of 2 mmol per mole of silver halide each.

Nothing was added to yet another IN. (Comparison 0) These anti-capri agent precursors (or anti-capri agents) are:
Added just before coating.

The remaining emulsion that was coated was kept warm at 40° C. and coated at regular intervals to check the stability of the emulsion over time of the anti-capri agent. These emulsions were coated in the same manner as in Example 1.

The obtained sample was heated at 40° C. for 5 days, and its photographic properties were examined in the same manner as in Example 1.

Next, each sample was developed for 6 minutes at 30° C. without exposure using the same developing solution as in Example 1 at pH 1o and 5, and the capri was examined. The results obtained are shown in Table 3.

(F5 As is clear from Invention Effect Table I, the compound of the present invention is more effective than Comparisons A, B, O1D, and E based on the sensitivity ratio data (sensitivity comparison when the sensitivity of Comparison A is set as 100.0). It can be seen that no undesirable decrease in sensitivity occurs.

Furthermore, it can be seen that there was very little softening of tone (decreasing of gamma value), and there was no adverse effect on photographic properties.

Furthermore, since the capri was extremely low and reached the level of capri in the comparative person, it was found that the capri was effectively decomposed in the developer and the capri inhibitor was released.

Furthermore, as is clear from Table (2), the anti-capri precursor of the present invention is superior in emulsion stability over time compared to comparative samples B and B.

Claims (1)

[Claims] (1) At least one silver halide emulsion layer and/or a colloid layer having a water-permeable relationship with the emulsion layer contains at least one compound represented by the following general formula (1) or general formula (II). Characteristic silver halide photographic material. General formula (I) ▲ Contains mathematical formulas, chemical formulas, tables, etc. ▼ General formula (II) ▲ Contains numerical formulas, chemical formulas, tables, etc. ▼ (In the formula, A represents the heterocyclic group of the mercaptocapric inhibitor, and R represents Represents a hydrogen atom, an alkyl group, or a phenyl group, and R_1 and R_2 represent a hydrogen atom, an alkyl group, and an aryl group, but neither R_1 nor R_2 is a hydrogen atom. R_1 is a hydrogen atom, an alkyl group, or a phenyl group. represents R_4, R_5, R_6 hydrogen atoms, halogen atoms,
Represents an alkyl group or phenyl group, general formula (I)
In the case of formula (II), R_4 and R_5, or in the case of general formula (II), R_4 and R_5 or R_5 and R_6 may be bonded to each other to form a benzene ring. )