JPH0571928B2 - - Google Patents

Description

[Detailed description of the invention]

(Industrial Application Field) The present invention relates to a method for producing a photographic silver halide emulsion. In particular, a method for producing a photographic silver halide emulsion consisting of tabular silver chloride grains with a grain size of three times or more the grain thickness, or silver chlorobromide, silver chloroiodide, or silver chloroiodobromide grains with a high silver chloride content. It is related to. (Prior Art) In order to increase the sensitivity of photographic silver halide emulsions, as well as sharpness, graininess, color sensitization efficiency by sensitizing dyes, and covering power, grain sizes are much larger than grain thickness. It is well known to those skilled in the art that so-called tabular grains are preferred. Additionally, increasing the silver chloride content increases water solubility, allowing faster development and fixing,
A silver halide suitable for rapid processing is obtained. Silver halide grains with a high silver chloride content (hereinafter referred to as "high silver chloride grains") generally tend to become cubic grains, and some measures are required to make them into tabular grains. For tabular grains with high silver chloride content of 50 mol% or more, bromide and iodide are not included, the pAg is in the range of 6.5 to 10, and the pH is maintained in the range of 8 to 10, and ammonia is added. U.S. patent 4399215 for particle formation using
No. 4,400,463, in which particles are formed in the coexistence of an aminoazaindene and a peptizer having a thioether bond, are known. However, the method using ammonia further increases the solubility of highly soluble silver chloride grains, making it difficult to produce relatively small emulsions with grain volumes of 1 μm ^or less, which are often used in rapid processing sensitive materials. This inevitably increases the pH during grain formation, which often increases fog in high-silver chloride emulsions that are sensitive to fog, and severely restricts grain formation conditions. In the method using a peptizer having a thioether bond, it is difficult to obtain a copolymer with good reproducibility because the peptizer is a synthetic polymer, the polymerization initiator contains impurities that are harmful to photography, and it is difficult to obtain a copolymer with good reproducibility. The drawback was that the salting process was complicated. In addition, there were many drawbacks from an industrial standpoint, such as the high cost required to eliminate these drawbacks. Based on the above, in the acidic to neutral range, by simply using a low-cost, low-molecular-weight compound that is easy to synthesize and purify in combination with gelatin, which is a general-purpose peptizer, it is possible to form a plate-shaped compound with good reproducibility. There has been a strong desire to develop a method for obtaining high silver chloride grains. (Objectives of the Invention) The first object of the present invention is to provide a method for producing a tabular silver halide emulsion with a high silver chloride content, which is suitable for rapid development processing and which progresses extremely quickly. The second object is to provide a new method for producing the emulsion in which the emulsion described above can be obtained with good reproducibility using a low-cost, low-molecular-weight compound that is easy to synthesize. (Means for Achieving the Object) As a result of intensive studies, the present inventors have found that by forming particles in the presence of a low molecular weight compound represented by the following general formula (), at least 50 mol% or more of A tabular high-silver chloride emulsion consisting of chloride, in which at least 50% of the total projected area of the emulsion grains has a grain size of 3 times or more the grain thickness, is easily obtained, and the above object is achieved. I found out what I can do. General formula ()

[Formula] In the formula, Z ¹ represents an atomic group necessary to form a saturated or unsaturated heterocycle with a sulfur atom,
This heterocycle may have a substituent. n represents 1, 2 or 3. Here, the atomic group represented by Z ¹ is formed from a carbon atom, a nitrogen atom, an oxygen atom, and a sulfur atom, and the heterocycle formed from Z ¹ and a sulfur atom is a 3- to 8-membered heterocycle; Rings may be fused with other rings to form fused rings. Specifically, thiirane, thietane, thiane, thiepin, thiocine, dihydrothiolane, thiophene, dihydrothiopyran, 4H-thiopyran, 2H
-thiopyran, 1,3-thiaziridine, thiazole, 1,3-oxathiolane, 1,3-dithiolane, 1,3-dithiolane, 1,3-dithiolene,
1,4-oxathiane, 1,4-thiazane, 1,
3-thiazane, benzothiolane, benzothian,
Examples include benzothiaziridine and benzosaxathian. Specific examples of substituents for the heterocycle formed from Z ¹ and a sulfur atom include halogen atoms (fluorine atoms, chlorine atoms, bromine atoms), alkyl groups (preferably those with 1 to 20 carbon atoms), aryl groups ( (preferably one having 6 to 20 carbon atoms), an alkoxy group (preferably one having 6 to 20 carbon atoms), an aryloxy group (preferably one having 6 to 20 carbon atoms), an alkylthio group (preferably one having 1 to 20 carbon atoms) ), arylthio group (preferably one having 6 to 20 carbon atoms), acyloxy group (preferably one having 2 to 20 carbon atoms), amino group (unsubstituted amino, preferably an alkyl group having 1 to 20 carbon atoms, or a secondary or tertiary amino group substituted with an aryl group having 6 to 20 carbon atoms), a carbonamide group (preferably an alkylcarbonamide group having 1 to 20 carbon atoms, an arylcarbonamide group having 6 to 20 carbon atoms) , ureido group (preferably 1 to 20 carbon atoms)
alkylureido group, arylureido group having 6 to 20 carbon atoms), carboxy group, carbonate group (preferably alkyl carbonate group having 1 to 20 carbon atoms, aryl carbonate group having 6 to 20 carbon atoms),
An oxycarbonyl group (preferably an alkyloxycarbonyl group having 1 to 20 carbon atoms, an aryloxycarbonyl group having 6 to 20 carbon atoms), a carbamoyl group (preferably an alkylcarbamoyl group having 1 to 20 carbon atoms, an alkylcarbamoyl group having 6 to 20 carbon atoms) arylcarbamoyl group),
Acyl group (preferably an alkylcarbonyl group having 1 to 20 carbon atoms, arylcarbonyl group having 6 to 20 carbon atoms), sulfo group, sulfonyl group (preferably an alkylsulfonyl group having 1 to 20 carbon atoms, 6 to 20 carbon atoms)
arylsulfonyl group), sulfinyl group (preferably an alkylsulfonyl group having 1 to 20 carbon atoms,
arylsulfonyl group having 6 to 20 carbon atoms), sulfonamide group (preferably alkylsulfonamide group having 1 to 20 carbon atoms, arylsulfonamide group having 6 to 20 carbon atoms), sulfamoyl group (preferably 6 to 20 carbon atoms) Examples include an alkylsulfamoyl group, an arylsulfamoyl group having 6 to 20 carbon atoms), a cyano group, a hydroxy group, a nitro group, an oxo group, a thioxo group, an imino group, and a selenoxo group. When there are two or more substituents, they may be the same or different. n represents 1-3. When n is 2 or 3, each carbonyl group may be adjacent or non-adjacent. Specific examples of the 5- to 6-membered saturated or unsaturated heterocycle represented by the general formula () include the following.

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[Formula] Among those represented by the general formula (), particularly preferred are those in which the carbonyl group is linked to a sulfur atom, and the heterocycle is saturated. Specific examples of the compound of the present invention represented by the general formula () are shown below.

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[Table] Synthesis examples of the compounds of the present invention are described below, and some of them are commercially available and can be easily obtained. Synthesis of Compound 1 38 g of thiourea and 47.3 g of chloroacetic acid were added to 100 ml of water and heated to reflux. One hour later, 10 ml of concentrated hydrochloric acid was added and the mixture was further heated under reflux for 4 hours. The reaction mixture was ice-cooled and crude crystals were collected. Recrystallize from 100ml of water,
Compound 1 was obtained. Yield: 42g (72%) Synthesis of Compound 4 Add 22.8g of thiourea and 37.5g of ethyl chloroacetate to 150ml of ethanol, and add sodium acetate.
21.9 g was added and heated under reflux for 1 hour. Leave to cool,
Compound 4 was obtained by taking the obtained crystals and washing them with water. Yield 25g (72%) Synthesis of compound 7 76g thiourea and 86g γ-butyrolactone at 47%
It was dissolved in 310 ml of hydrogen bromide and heated under reflux for 19 hours.
After cooling, add 150g of sodium hydroxide to 200ml of water.
A solution dissolved in water was added little by little, and the mixture was heated under reflux for 3 hours. 110 ml of concentrated sulfuric acid was added little by little while cooling on ice.
Compound 7 was obtained by extraction with 150 ml of ether and distillation under reduced pressure. bp90-91°C/23mmHg Yield 39g (38%) Synthesis of Compound 10 14g of cyanamide synthesized by the method of Org.Synth.Coll.Vol. 4 , 645 and 30g of thiosalicylic acid were dissolved in 60ml of tetrahydrofuran and heated under reflux for 70 minutes. It was cooled to 0°C and yellow crystals were collected. The crystals were dissolved in 30 ml of 6N hydrochloric acid and heated under reflux for 5 hours. After cooling, the obtained crystals were collected and recrystallized from ethanol to obtain Compound 10. Yield: 12.1 g (48%) The amount of the compound represented by the general formula () of the present invention can be in the range of 2 x 10 ^-5 mol to 3 x 10 ^-1 mol per 1 mol of silver halide. , 2×
Particularly preferred is 10 ^-4 mol to 1 x 10 ^-1 mol. The compound of the present invention may be added at any time during grain formation from the time of nucleation of silver halide grains to the end of physical ripening in the production process of silver halide emulsions. , is preferably present at least in part from the beginning of grain formation. The compounds of the present invention are easy to synthesize, purify and handle, and as described in Examples,
It has the great advantage that tabular high-silver chloride grains can be easily obtained by simply using it in combination with a gelatin solution, which is a general-purpose peptizer, in the formation of silver halide grains. Some of the compounds represented by the general formula () of the present invention are known, for example, from Japanese Patent Publication No. 188036/1983, which describes that in the presence of these compounds, This method involves chemical ripening, and is completely different from the present invention both in purpose and effect. The temperature during particle formation in the present invention can be used in the range of 10°C to 95°C, preferably 40°C to 90°C.
It is. The pH may be any value, but is preferably in the neutral to acidic range. The chloride concentration during nucleation is 0.05 mol/more,
Preferably 0.10 mol/or more, more preferably
It is preferably 0.15 mol/or more, and the chloride concentration during grain growth is about 0.07 to 5.0 mol/, preferably 0.1 to 3.0 mol/. The tabular high silver chloride grains of the present invention refer to those having a silver chloride content of at least 50 mol %.
Preferably it is 70 mol%, more preferably 90 mol% or more. The remainder consists of silver bromide and/or silver iodide, and the content of silver iodide is preferably 20% or less, preferably 10 mol% or less. It is particularly desirable that a layer mainly composed of silver bromide or silver iodide be localized near the surface of the grains. Further, in the case of so-called core/shell type grains, it is preferable that the silver chloride content in the core portion is higher than that in the shell portion. For example, particles may be composed of a core portion made of silver chloride and a shell portion made of silver bromide. The tabular silver halide grains of the present invention preferably have a diameter/thickness ratio of 3 or more, more preferably 3 or more and 50 or less, particularly preferably 3 or more and 20 or less, and 3 or more and 10 or less. Most preferred. The diameter of a silver halide grain herein refers to the diameter of a circle having an area equal to the projected area of the grain. In the present invention, the diameter of the tabular silver halide grains is 0.3 to 5.0μ,
Preferably it is 0.5-3.0μ. Further, the thickness is 0.4 μm or less, preferably 0.3 μm or less, and more preferably 0.2 μm or less. The average volume of the particle volume load is preferably 2 μm ³ or less. Further, it is preferably 0.8 μm ³ or less. Generally, tabular silver halide grains are tabular with two parallel surfaces, and therefore, "thickness" in the present invention refers to the distance between the two parallel surfaces constituting the tabular silver halide grains. It is expressed as Further, it may be an internal latent image type tabular grain emulsion or a surface latent image type tabular grain emulsion. The size of the tabular silver halide grains can be adjusted by controlling the temperature, selection of the type and amount of solvent, the silver salt used during grain growth, the addition rate of halide, etc. By using a silver halide solvent during production of the tabular silver halide grains of the present invention, the grain size, grain shape (diameter/thickness ratio, etc.), grain size distribution, and grain growth rate can be controlled. Examples of frequently used silver halide solvents include thiocyanates, thioethers, thioureas, etc. Ammonia can also be used in combination as long as it does not cause any adverse effects. For example, thiocyanate (U.S. Pat. No. 2,222,264;
2448534, 3320069, etc.), thioether compounds (for example, U.S. Pat. No. 3271157, 3320069, etc.),
3574628, 3704130, 4297439, 4276347, etc.), thione compounds (for example, JP-A-Sho
53-144319, 53-82408, 55-77737, etc.), amine compounds (for example, JP-A-54-100717, etc.) can be used. In the process of silver halide grain formation or physical ripening, a cadmium salt, a zinc salt, a lead salt, a thallium salt, an iridium salt or a complex salt thereof, a rhodium salt or a complex salt thereof, an iron salt or an iron complex salt, etc. may be present. Particularly preferred are iridium salts or rhodium salts. For example, as the amount of solvent used increases, the particle size distribution can be made monodisperse and the growth rate can be accelerated. On the other hand, there is also a tendency for the thickness of the particles to increase with the amount of solvent used. When producing the tabular silver halide grains of the present invention,
Silver salt solutions (e.g. AgNO ₃ aqueous solution) and halide solutions (e.g.
A method of increasing the addition rate, amount, and concentration of KBr aqueous solution) is preferably used. These methods are described, for example, in British patent no.
1335925, U.S. Patent No. 3672900, U.S. Patent No. 3650757
No. 4242445, JP-A-55-142329, No. 55
−158124, No. 58-113927, No. 58-113928,
Reference may be made to the descriptions in No. 58-111934, No. 58-111936, etc. The tabular silver halide grains of the present invention may be left unchemically sensitized, but can be chemically sensitized if necessary. Chemical sensitization methods include gold sensitization using so-called gold compounds (for example, U.S. Pat. No. 2,448,060;
3320069) or iridium, platinum, rhodium,
Sensitization using metals such as palladium (e.g., U.S. Pat. No. 2,448,060, U.S. Pat. No. 2,566,245, U.S. Pat. No. 2,566,263), sulfur sensitization using a sulfur-containing compound (eg, U.S. Pat. No. 2,222,264), selenium sensitization using a selenium compound. method or reduction sensitization method using tin salts, thiourea dioxide, polyamines, etc. (for example, U.S. Patent No.
No. 2487850, No. 2518698, No. 2521925), or a combination of two or more of these can be used. Particularly from the viewpoint of saving silver, the tabular silver halide grains of the present invention are preferably gold-sensitized, sulfur-sensitized, or a combination thereof. The emulsion layer of the silver halide photographic light-sensitive material of the present invention may contain ordinary silver halide grains in addition to tabular silver halide grains. The emulsions of this invention may be spectrally sensitized with methine dyes and others. The dyes used include cyanine dyes, merocyanine dyes, complex cyanine dyes, complex merocyanine dyes, holopolar cyanine dyes, hemicyanine dyes, styryl dyes and hemioxonol dyes. Particularly useful dyes are those belonging to the cyanine dyes, merocyanine dyes, and complex merocyanine dyes. Any of the nuclei commonly used for cyanine dyes can be used as the basic heterocyclic nucleus for these dyes. That is, pyrroline nucleus, oxazoline nucleus,
Thiazoline nucleus, pyrrole nucleus, oxazole nucleus, thiazole nucleus, selenazole nucleus, imidazole nucleus,
Tetrazole nucleus, pyridine nucleus, etc.; nucleus in which an alicyclic hydrocarbon ring is fused to these nuclei; and nucleus in which aromatic hydrocarbon ring is fused to these nuclei, i.e., indolenine nucleus, benzindolenine nucleus, indole nucleus , benzoxadole nucleus, naphthoxazole nucleus, benzothiazole nucleus, naphthothiazole nucleus,
benzoselenazole nucleus, benzimidazole nucleus,
Quinoline nuclei etc. can be applied. These nuclei may be substituted on carbon atoms. Merocyanine dyes or composite merocyanine dyes have a ketomethylene structure as a nucleus such as a pyrazolin-5-one nucleus, a thiohydantoin nucleus, a 2-thioxazolidine-2,4-dione nucleus, a thiazolidine-2,4-dione nucleus, a rhodanine nucleus, and a thiazolidine-2,4-dione nucleus. A 5- to 6-membered heteroartic ring nucleus such as a barbiturate nucleus can be applied. For example, RESERCH DISCLOURE Item.17643,
Compounds described on page 23 (December 1978) or compounds described in the cited literature can be used. Typical specific examples include the following methine dyes.

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[Table] The dye may be added to the emulsion at any stage of emulsion preparation known to be useful. Although it is normally carried out after the completion of chemical sensitization and before application, US Patent No.
3628969 and 4225666, it is also possible to add the chemical sensitizer at the same time and perform spectral sensitization at the same time as chemical sensitization.
It can be carried out prior to chemical sensitization as described in No. 113928, or it can be added before the completion of silver halide grain precipitation to initiate spectral sensitization. Furthermore, these compounds may be added separately as taught in U.S. Pat. No. 4,225,666, i.e. some of these compounds may be added prior to chemical sensitization and the remainder may be added after chemical sensitization. It can also be added at any time during silver halide grain formation, including by the method taught in US Pat. No. 4,183,756. The amount added is 4×10 ^-6 per mole of silver halide.
Although it can be used in an amount of about 8 x 10 ^-3 mol, about 5 x 10 ^-5 to 2 x 10 ^-3 mol is more effective when the silver halide grain size is more preferably 0.2 to 1.2 μm. The silver halide emulsion prepared according to the present invention can be used in both color photographic materials and black and white photographic materials. Examples of color photographic materials include color paper, film for color photography, color reversal film, and examples of black and white photographic materials include X-ray film, film for general photography, film for printing sensitive materials, etc. It can be preferably used for color paper. There are no particular restrictions on other additives for the photographic material to which the emulsion of the present invention is applied.
Disclosure) Volume 176 Item 17643 (RD17643) and Volume 187 Item 18716 (RD18716) can be referred to. The locations where various additives are described in RD17643 and RD18716 are listed below.

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[Table] Agent

Claims (1)

[Scope of Claims] 1. A photographic silver halide emulsion comprising silver halide grains in which at least 50 mol % is silver chloride, the silver halide emulsion comprising at least 50 mol % of the total projected area of the silver halide grains.
To produce a photographic silver halide emulsion in which 50% of the grains are tabular silver halide grains with a grain size of three times or more the grain thickness by forming grains in the presence of a compound of the following general formula (). Features: A method for producing photographic silver halide emulsions. General formula () [Formula] In the formula, Z ¹ represents an atomic group necessary to form a saturated or unsaturated heterocycle with a sulfur atom,
This heterocycle may have a substituent. n is 1, 2
Or represents 3.