JP2556938B2 - Method for producing silver halide emulsion - Google Patents

Description

Detailed Description of the Invention

[0001]

FIELD OF THE INVENTION The present invention relates to a method for producing a silver halide photographic emulsion, and more particularly to a method for producing a silver halide photographic emulsion using a novel thioether compound.

[0002]

2. Description of the Related Art The silver halide crystal grains used in a silver halide photographic emulsion have various grain sizes and crystal habits according to the purpose, and conventionally, in order to control them,
Various particle size control agents and crystal habit control agents have been used. The thioether compound is also used as a chemical sensitizer, but since it acts as a solvent for silver halide, it has long been used as a grain size control agent.

For example, US Pat. Nos. 3,271,157 and 3
531289, 3754628, 4057429.
Nos. And specifications, the presence of a thioether compound during the precipitation step and physical ripening in the production of silver halide photographic emulsions (hereinafter simply referred to as "emulsion") allows silver halide grains to have a uniform size, so-called monodispersion. Techniques for making emulsions are disclosed.

Further, US Pat. Nos. 2,521,926 and 3,
No. 021215, No. 3038805, No. 350644
No. 3, No. 3057724, No. 3062646, No. 3
No. 574709, No. 3622329, No. 362569
No. 7, etc. disclose a method of increasing the sensitivity of a photographic emulsion by allowing a thioether compound to be present at the time of chemical ripening during emulsion production or immediately before coating.

[0005]

However, addition of a thioether compound to an emulsion tends to increase fog.

In order to prevent the fog caused by the thioether compound, for example, a technique of precipitating at a pH value of 4 or less or superpurifying the thioether compound is known, but the effect is insufficient, There are drawbacks such as not being practical on an industrial scale.

Further, as described in JP-B-58-27489, it is used in combination with a specific antifoggant, or JP-B-58-30571 and US Pat.
Although thioether compounds such as those described in JP-A-5535 and JP-A-62-14646 have been developed, it has been desired to develop a compound capable of producing less fog and achieving high sensitivity.

Therefore, an object of the present invention is to provide a method for producing a silver halide emulsion composed of silver halide grains having a large grain size by using a novel thioether compound.

Another object of the present invention is to provide a method for producing an emulsion having high sensitivity and less fog using a novel thioether compound.

[0010]

The object of the present invention can be achieved by a method for producing a silver halide photographic emulsion characterized by using a compound represented by Chemical formula 1.

[In the formula, R ₁ represents H or an alkyl group or an aryl group, R ₂ represents OH or compound 2, and R ₃ represents an alkylene group. Further, n represents an integer of 1 to 3. R ₄ ,
R ₅ represents H or an alkyl group. ]

Specific examples of the novel thioether compound used in the present invention are shown below, but the invention is not limited thereto.

[0013]

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[0014]

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[0015]

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[0016]

[Chemical 6]

[0017]

[Chemical 7]

[0018]

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[0019]

[Chemical 9]

The synthesis of the novel thioether compound used in the present invention is described in JCS (1950) 72-1879, JOC (1953) 24.
470-473, BuLL.Chem.Soc. (1967) 40-2854, JOC (19
60) 25 1742, Ann. Chem. (1961) 643 121, Pharmaceutical Journal (196
8) It can be synthesized with reference to 85-1537, Japanese Examined Patent Publication Nos. 39-26203 and 60-11341. The details of the synthesis method will be described below using synthesis examples.

Synthetic Example (Synthesis of Compound of Chemical Formula 3) A mixture of 2-amino 2'-hydroxydiethyl sulfide 4.81 g, triethylamine 4.86 g, and ethyl alcohol 100 ml was prepared.
Keep the internal temperature at 0 ° C and add 3.35 g of carbon disulfide with stirring.
After stirring for 2 hours at room temperature, heat at 50 ° C for 30 minutes. The temperature was again maintained at 0 ° C., and 3.83 g of chloroacetone was added. After stirring at room temperature for 1 hour and heating at 40 ° C for 2 hours, ethyl alcohol was distilled off, water was added to the residue, extracted with ethyl acetate, washed with water, and dried over sodium sulfate. After the ethyl acetate was distilled off, the residue was chloroform / methanol =
Column chromatography from 10/1. Pale yellow oil
7.81 g was obtained. CMR (CDCl ₃ ) δ 195.1, 97.7 61.
0 45.0 41.9 34.7 28.9 24.9

In the present invention, the novel thioether compound is added in at least one step selected from the steps of silver halide precipitation formation during emulsion production, subsequent physical ripening, chemical ripening and immediately before coating. It is preferable. In particular, it is preferably added at the time of precipitation formation, physical ripening, or chemical ripening.

The silver halide grains used in the present invention can be formed by a general method well known in the art, but the double jet method is particularly preferable.

The double jet method is a silver nitrate aqueous solution,
An aqueous solution of one or more halides (eg, halides of alkali metals such as potassium bromide) is added simultaneously to 2
It is a method in which silver halide grains are formed by virtue of vigorous stirring into a protective colloid of silver halide such as gelatin by two separate jets.

In the present invention, when the novel thioether compound is added during the precipitation of silver halide and / or during the physical ripening, it is preferable to add it to the protective colloid solution before starting the precipitation. It may be added to the protective colloid solution together with the jet of the silver nitrate solution or the halogen solution, or as a separate jet.

When the novel thioether compound of the present invention is added to the above solution, water, methanol, ethanol, D
It may be added after being dissolved in a suitable solvent such as MF, acetone, ethyl acetate or in the form of a dispersion liquid dispersed in these solvents.

The conditions such as pH, pAg and temperature during the formation of silver halide grains in the present invention are not particularly limited, but the pH is not limited.
The value is 1 to 10, particularly 2 to 8, and the pAg is
It is preferable to keep it at 5 to 11, especially at 7-10.5. The temperature is preferably between 30 and 90 ° C, particularly preferably 35 to 80 ° C. These conditions may be changed during the formation of silver halide grains.

The amount of the novel thioether compound of the present invention added during the formation of silver halide grains is 1
It is preferably 0.01 to 100 g per mol.

Further, at the same time as the novel thioether compound of the present invention, the above-mentioned known thioether compound, ammonia, thiocyanate (eg, rhodancari), and
JP-B-58-51252, JP-A-55-77737
No. 4,218,863, Japanese Patent Publication No. 60-1134
You may use together with the compound as described in No. 1 etc.

When the novel thioether compound of the present invention is used before chemical ripening (for example, during formation of silver halide grains), it functions as a silver halide solvent by the method described in JP-A-60-136736. Can be deactivated.

In the present invention, as described above, the thioether compound can be added in the chemical ripening step or the step immediately before coating. In this case, the addition amount of the novel thioether compound of the present invention is 0.1 per mol of silver halide.
001 to 10 g, particularly 0.01 to 5 g is preferable.

There are no particular restrictions on the conditions of the chemical ripening step in the present invention, such as pH, pAg, temperature, time and additives, and it can be carried out under the conditions generally used in the art.

Next, the photographic emulsion used in the present invention contains silver bromide such as silver bromide, silver iodobromide, silver iodochlorobromide, silver chlorobromide, silver iodide and silver chloride. Either may be used.

The particle size distribution may be narrow or wide.

The silver halide grains in the photographic emulsion may have a regular crystal such as a cube, an octahedron, a tetrahedron and an orthorhombic dodecahedron, and may have an irregular shape such as a spherical shape or a plate shape. It may have a crystal system, or may have a composite form of these crystal forms. It may also consist of a mixture of grains of various crystal forms.

The silver halide grains may have different phases in the inside and the surface layer, or may have a uniform phase.

Further, for example, a composite type silver halide crystal in which an oxide crystal such as PbO and a silver halide crystal such as silver chloride are combined, or an epitaxially grown silver halide crystal (for example, It is also possible to epitaxially grow silver chloride, silver iodobromide, silver iodide, etc. on silver bromide).

The aspect ratio is 3 or more, preferably 5
To 20 tabular silver halide grains can also be used. For more details, see U.S. Pat.
No. 39520, JP-A-59-99433, "Research Disclosure" Vol. 225, No. 22534 (1
Jan. 983).

The grain size distribution of the silver halide grains used in the present invention is arbitrary, but it may be monodisperse. Here, monodisperse refers to a dispersion system in which 95% of particles are within ± 60% of the number average particle size, preferably within 40%. Here, the number average grain size is the number average diameter of the projected area diameters of silver halide grains.

The photographic emulsion used in the present invention is Photographic by GDFuffin.
Emulsion Chemistry (Photographic EmulsionC
hemistry, The Focal Pres
s) (1966), VLZelikman et al, Making and Coating Photographic Emulsion (Making and Coating)
Coating Photo-graphic Emulsion), The Focal
The adjustment can be performed using a method described in, for example, the Press (The Focal Press) (1964). That is, any of an acidic method, a neutral method, an ammonia method and the like may be used, and a method of reacting a soluble silver salt and a soluble halide may be any one of a one-sided mixing method, a double-sided mixing method, and a combination thereof. Good.

As one form of the simultaneous mixing method, a method of keeping pAg constant in a liquid phase in which silver halide is produced, that is, a controlled double jet method can be used. According to this method, a silver halide emulsion having a regular crystal form and a substantially uniform grain size can be obtained.

Further, two or more kinds of silver halide emulsions formed separately may be mixed.

In the course of silver halide grain formation or physical ripening, cadmium salt, zinc salt, lead salt, thallium salt,
An iridium salt or a complex salt thereof, a rhodium salt or a complex salt thereof, and the like may coexist.

As the method for removing the soluble salts from the emulsion after the formation of the precipitate or after the physical preparation, the noodle method for gelling gelatin, inorganic salts, anionic surfactants, anionic polymers or modified gelatin are used. The precipitation method (flocculation method) or the like is used.

The silver halide emulsion is chemically sensitized by a conventional method. Examples of the sulfur sensitizer include thiosulfate, thiourea, allylisothiocyanate, cystine and rhodanine, and US Pat. Nos. 1,574,944 and 22,789,47.
No. 2410689, No. 2440206, No. 31
87458, 3415649, and 3501313.
A sulfur-containing compound such as those described in Japanese Patent Publication No. 1994-242242 can be used. Also, with sulfur sensitization, US Pat.
No. 60, No. 2540036, No. 2556245, No. 2566263, and the sensitization method using a salt of a noble metal such as platinum palladium, iridium, rhodium, and ruthenium can be used in combination.

In the present invention, for example, known stabilizers such as mercaptotetrazole, mercaptotriazole, benzotriazole and benzimidazole, antifoggants, and various developing agents such as polyalkylene oxides, thioether compounds and quaternary ammonium salt compounds. Accelerators can be used.

Examples of the hydrophilic colloid used in the present invention include proteins such as gelatin, colloidal albumin and casein, cellulose derivatives such as carboxymethyl cellulose, agar, sodium alginate, sugar derivatives such as starch, polyvinyl alcohol and polyacrylamide. These synthetic polymers and the like can be used alone or in admixture at an appropriate ratio.

The support used in the present invention is a film usually used for photographic light-sensitive materials such as films such as cellulose acetate film and polyethylene terephthalate film, baryta or paper coated or laminated with polyethylene, polypropylene and the like. Any of them will do.

In addition to these, various compounds such as a hardener, a surfactant, an antistatic agent, a plasticizer and a matting agent are added to the light-sensitive material of the present invention in order to control the properties of the material. Good.

[0050]

EXAMPLES The present invention will be specifically described below with reference to examples, but it is needless to say that the present invention is not limited by these descriptions.

Example 1 60 ml of 300 ml of an aqueous solution containing gelatin and potassium bromide was used.
1N. Silver nitrate aqueous solution, 1
A mixed aqueous solution of N. potassium bromide and potassium iodide was added at 200 cc and pAg at 7.2 at the same time over 90 minutes to obtain a monodisperse cubic silver bromide emulsion containing about 1 mol% of silver iodide. Obtained. At this time, before starting the addition of the aqueous silver nitrate solution and the aqueous halogen solution, 4 × 10 ⁻⁵ mol of the thioether compound shown in Table 1 was added to the gelatin solution. A part of the silver halide emulsion thus obtained was taken, and an electron micrograph was taken to measure the grain size of each silver halide emulsion grain. The silver halide grain diameters shown in the table are the number average grain diameters measured on an electron micrograph for each side of the cubic grain of about 500 grains.

[0052]

[Table 1]

The following compound was used as a comparative compound.

[0054]

[Chemical 10]

From these results, it is understood that the thioether compound of the present invention is an extremely effective silver halide grain size control agent and is effective for obtaining a large grain silver halide crystal even when added in a small amount.

Example 2 In the same manner as in Example 1, a monodisperse cubic silver bromide emulsion containing 1 mol% of silver iodide was obtained. At this time, the compounds shown in Table 2 were added in respective amounts to control the grain size of silver halide grains.

The emulsion thus obtained was precipitated by a flocculation method and washed with water to remove unnecessary salts and redissolved, and then gelatin was added so that the ratio of silver to gelatin was 1: 0.8. Next, hypo and chloroauric acid were added, and chemical aging was performed at pAg = 8.0, pH = 6.0 and 55 ° C. for 90 minutes to give 4-hydroxy-6-methyl-1,3,3a, 7.
-After adding tetrazaindene as a stabilizer, the following sensitizing dye (Chemical Formula 11) was added, and further an antifoggant, a surfactant and a hardener were added to obtain a finished emulsion. this,
It was coated on RC paper laminated with PE so as to be 2.5 g per square meter in terms of silver nitrate.

[0058]

[Chemical 11]

The finished sample was exposed for 10 to ⁵ seconds using a xenon flash lamp through an interference filter of 633 nm and a step wedge, and was developed with an automatic processor using a developer for ordinary high temperature rapid processing.

Next, the density of each step of the step-wedge exposed sample was measured to obtain a normal characteristic curve,
The relative exposure dose required to obtain a reflection density of 1.0 was determined. Table 2 shows the measurement results of the sensitivity value, fog, and silver halide grain size of each emulsion. The sensitivity value is emulsion No. As a relative value when the sensitivity of 1 is 100,
Fog is represented by the reflection density of the unexposed area. The silver halide grain size was measured in the same manner as in Example 1, and the unit of numerical values shown in the table is μm.

[0061]

[Table 2]

From the above results, it can be seen that by producing a silver halide emulsion using the novel thioether compound of the present invention, excellent sensitivity and excellent characteristics with less fog can be obtained.

[0063]

The method for producing a silver halide emulsion using the novel thioether compound of the present invention makes it possible to easily obtain a silver halide emulsion having a large grain size, and to obtain high sensitivity and excellent fog characteristics. A silver halide photographic emulsion having the same can be obtained.

 ─────────────────────────────────────────────────── ─── Continuation of the front page (56) References JP-A-4-289848 (JP, A) JP-A-2-97939 (JP, A) JP-A-3-211544 (JP, A) JP-B-59- 11892 (JP, B2) JP 58-8503 (JP, B2) JP 58-27486 (JP, B2) JP 62-2301 (JP, B2)

Claims (1)

(57) [Claims] 1. A method for producing a silver halide photographic emulsion, which comprises using a compound represented by the following general formula 1. Embedded image [Wherein R ₁ is H or an alkyl group or an aryl group,
R ₂ represents OH or compound 2 and R ₃ represents an alkylene group. Further, n represents an integer of 1 to 3. Embedded image R ₄ and R ₅ represent H or an alkyl group. ]