JPH04311947A - Manufacture of silver halide emulsion - Google Patents

Abstract

PURPOSE:To manufacture highly sensitive emulsion hardly causing photographic halation by using a specific thioether compound. CONSTITUTION:Emulsion is manufactured by using a compound as shown by an equation I. In the equation I, R shows H, an alkyl group and an aryl group, and R2 shows OH, and R3 shows an alkylene group, and (n) shows integer of 1-3. In the equation II, R4 and R5 show H and an alkyl group. A double jet method is desirable for forming silver halide particulates, and aqueous solution of silver nitrate and aqueous solution of halide are added together to protective colloid of silver halide by means of two jets while stirring them so that the silver halide particulates can be formed. Furthermore, in the case of adding a specific thioether compound while sedimentation of the silver halide is being produced, before the sedimentation is started, or together with jets, it can be added to the protective colloid solution.

Description

[Detailed description of the invention]

0001

BACKGROUND OF THE INVENTION 1. 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

BACKGROUND OF THE INVENTION Silver halide crystal grains used in silver halide photographic emulsions have various grain sizes and crystal habits depending on the purpose, and in order to control these, conventionally,
Various particle size control agents and crystal habit control agents have been used. Although thioether compounds are also used as chemical sensitizers, they have long been used as grain size control agents because they act as solvents for silver halide.

For example, US Pat. No. 3,271,157 and US Pat.
No. 531289, No. 3574628, 4057429
In the No. 1, specification, etc., silver halide grains are made uniform in size by making a thioether compound present during the precipitation process and physical ripening of silver halide photographic emulsion (hereinafter simply referred to as emulsion) production, so-called monodispersion. Techniques for making emulsions are disclosed.

[0004] Also, US Pat. No. 2,521,926, US Pat.
No. 021215, No. 3038805, No. 350644
No. 3, No. 3057724, No. 3062646, No. 3
No. 574709, No. 3622329, No. 362569
No. 7, etc., discloses a method of increasing the sensitivity of photographic emulsions by making a thioether compound present during chemical ripening during emulsion production or immediately before coating.

[0005]

However, the addition of thioether compounds to emulsions tends to increase fog.

[0006] In order to prevent this fogging caused by thioether compounds, techniques are known, such as precipitation at a pH value of 4 or less or ultra-purification of thioether compounds, but the effects are insufficient or It has drawbacks such as being impractical on an industrial scale.

[0007] Furthermore, as described in Japanese Patent Publication No. 58-27489, it may be used in combination with a certain antifoggant;
Although thioether compounds such as those described in No. 535 and JP-A-62-14646 have been developed, it has been desired to develop a compound that causes less fog and can achieve higher sensitivity.

[0008] Accordingly, an object of the present invention is to provide a method for producing a silver halide emulsion comprising silver halide grains of large grain size using a novel thioether compound.

Another object of the present invention is to provide a method for producing an emulsion with high sensitivity and low fog using a new thioether compound.

0010

[Means for Solving the Problems] The object of the present invention has been achieved by a method for producing a silver halide photographic emulsion, which is characterized by using a compound represented by formula (1).

[In the formula, R1 represents H or an alkyl group or an aryl group, R2 represents OH or a chemical formula 2, and R3 represents an alkylene group. Further, n represents an integer from 1 to 3. R4
, R5 represents H or an alkyl group. ]

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

[0013]

[Chemical formula 3]

[0014]

[C4]

[0015]

[C5]

[0016]

[C6]

[0017]

[C7]

[0018]

[Chemical formula 8]

[0019]

[Chemical formula 9]

The synthesis of the novel thioether compounds used in the present invention is described in J. C. S. (1950) 72-187
9, J. O. C. (1953) 24 470-473
, BuLL. Chem. Soc. (1967) 40-
2854, J. O. C. (1960) 25 1742
, Ann. Chem. (1961) 643 121
, Yakugaku Zasshi (1968) 85-1537, Japanese Patent Publication No. 39-26203, No. 60-11341, etc. for synthesis. The details of the synthesis method will be described below using synthesis examples.

Synthesis Example (Synthesis of Compound 3) 2-amino 2'-hydroxydiethyl sulfide 4.81g, triethylamine 4.86g, ethyl alcohol 10
3.35 g of carbon disulfide is added to 0 ml of the mixture while stirring while keeping the internal temperature at 0°C. After stirring at room temperature for 2 hours, heat at 50°C for 30 minutes. The temperature was maintained at 0° C. again, and 3.83 g of chloroacetone was added. Room temperature stirring 1
After 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 with sodium sulfate. After distilling off ethyl acetate, the residue was subjected to column chromatography using chloroform/methanol = 10/1. 7.81 g of pale yellow oil was obtained. CMR(CDCl3
) δ195.1, 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 formation of silver halide precipitate, the subsequent physical ripening, the chemical ripening, and immediately before coating during emulsion production. is preferred. In particular, it is preferable to add it during precipitate formation, physical ripening, or chemical ripening.

As a method for forming the silver halide grains used in the present invention, general methods well known in the art can be used, but the double jet method is particularly preferred.

[0024] The double jet method uses a silver nitrate aqueous solution,
An aqueous solution of one or more halides (e.g., an alkali metal halide such as potassium bromide) is simultaneously
In this method, silver halide grains are formed by adding silver halide particles into a protective colloid of silver halide, such as gelatin, with vigorous stirring using two separate jets.

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

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

There are no particular restrictions on the conditions such as pH, pAg, temperature, etc. during the formation of silver halide grains in the present invention;
As a value, 1 to 10, especially 2 to 8, as pAg,
It is preferable to keep it at 5 to 11, especially 7 to 10.5. The temperature is preferably between 30 and 90°C, particularly between 35 and 80°C. These conditions may be changed during silver halide grain formation.

The amount of the novel thioether compound of the present invention added during the formation of silver halide grains is as follows: silver halide 1
0.01 to 100 g per mole is preferred.

In addition to the novel thioether compound of the present invention, the above-mentioned known thioether compounds, ammonia, thiocyanate (such as rhodanpotash) and
JP 58-51252, JP 55-77737, U.S. Patent No. 4221863, JP 60-11341
It may be used in combination with the compounds described in No.

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

In the present invention, as described above, the thioether compound can be added in the chemical ripening step or in the step immediately before coating. In this case, the amount of the novel thioether compound of the present invention added is 0.000.
001-10g, particularly 0.01-5g is preferred.

The conditions for the chemical ripening step in the present invention, such as pH, pAg, temperature, time, additives, etc., are not particularly limited and can be carried out under conditions commonly used in the industry.

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

Further, the particle size distribution may be narrow or wide.

The silver halide grains in the photographic emulsion may have a regular crystal structure such as a cube, an octahedron, a tetradecahedron, or a rhombic dodecahedron, or may have an irregular crystal structure such as a spherical shape or a plate shape. It may have a crystalline system or a composite of these crystalline forms. Further, it may be composed of a mixture of particles of various crystal forms.

The silver halide grains may have different phases inside and on the surface, or may consist of a uniform phase.

Further, for example, composite silver halide crystals in which an oxide crystal such as PbO and a silver halide crystal such as silver chloride are combined, epitaxially grown silver halide crystals (for example, Alternatively, silver chloride, silver iodobromide, silver iodide, etc. may be grown epitaxially on silver bromide.

[0038] Also, the aspect ratio is 3 or more, preferably 5
-20 tabular silver halide grains can also be used. For more details, see U.S. Pat. Nos. 4,434,226 and 443
No. 9520, JP-A No. 59-99433, "Research Disclosure" Vol. 225, No. 22534 (19
(January 1983), etc.

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

The photographic emulsion used in the present invention is based on the book "Photographic Emulsion Chemistry" by G.F. Duffin.
graphic Emulsion Chemistry
y), The Focal Press (The Foca
Press) (1966), V.L.
V.L. Zelikman et al.
al) Making and Coating Photographic Emulsion
dCoating Photo-graphic E
mulsion), The Focal Press (Th
It can be adjusted using the method described in e.g. Focal Press (1964). That is, any of the acidic method, neutral method, ammonia method, etc. may be used, and the method for reacting the soluble silver salt with the soluble halogen salt may be any one-sided mixing method, simultaneous mixing method, or a combination thereof. good.

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

Furthermore, two or more types of silver halide emulsions formed separately may be mixed.

In the process 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, or the like may be present together.

[0044] Methods for removing soluble salts from the emulsion after precipitation or physical training include the noodle method of gelatin gelling, inorganic salts, anionic surfactants, anionic polymers, modified gelatin, etc. A precipitation method (flocculation method), etc., is used.

The silver halide emulsion is chemically sensitized by a conventional method. Examples of the sulfur sensitizer include thiosulfate, thiourea, allyl isothiacyanate, cystine, rhodanine, and US Pat. Nos. 1,574,944 and 2,278,947.
No. 2410689, No. 2440206, No. 31
No. 87458, No. 3415649, No. 3501313
Sulfur-containing compounds such as those described in No. 1, etc. can be used. Additionally, along with sulfur sensitization, U.S. Patent No. 24480
It is possible to use a combination of sensitization methods using noble metal salts such as platinum palladium, iridium, rhodium, and ruthenium, which are described in No. 60, No. 2540036, No. 2556245, and No. 2566263.

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

Hydrophilic colloids 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. Synthetic polymers such as the following can be used alone or in combination in an appropriate ratio.

Supports used in the present invention include films such as cellulose acetate film and polyethylene terephthalate film, and those commonly used in photographic materials, such as paper coated or laminated with baryta, polyethylene, polypropylene, etc. Either one is fine.

In addition to these, various compounds such as hardeners, surfactants, antistatic agents, plasticizers, and matting agents may be added to the photosensitive material of the present invention in order to control the properties of the material. Good too.

[0050]

EXAMPLES The present invention will be specifically explained below with reference to Examples, but the present invention is of course not limited to these descriptions.

Example 1 300 ml of aqueous solution containing gelatin and potassium bromide
was maintained at 60°C and heated to 1N while stirring vigorously. Silver nitrate aqueous solution and 1N. 200 cc of a mixed aqueous solution of potassium bromide and potassium iodide were simultaneously added over 90 minutes while keeping the pAg at 7.2 to form a monodisperse cubic silver bromide emulsion containing about 1 mol% silver iodide. Obtained. At this time, before starting the addition of the silver nitrate aqueous solution and the halogen aqueous solution, the thioether compound shown in Table 1 was added 4x to the gelatin solution.
10-5 mol was added. A portion of the silver halide emulsion thus obtained was taken, an electron micrograph was taken, and the grain size of each silver halide emulsion grain was measured. The silver halide grain sizes shown in the table are expressed by the number average grain size obtained by measuring the length of one side of about 500 cubic grains on an electron micrograph.

[0052]

[Table 1]

The following chemical formula 10 was used as a comparative compound.

[0054]

[Chemical formula 10]

These results show that the thioether compound of the present invention is an extremely effective silver halide grain size control agent, and is effective in obtaining large grain silver halide crystals even when added in a small amount.

Example 2 A monodisperse cubic silver bromide emulsion containing 1 mol % of silver iodide was obtained in the same manner as in Example 1. At this time, the grain size of the silver halide grains was controlled by adding the compounds shown in Table 2 in respective amounts.

The emulsion thus obtained was precipitated by the flocculation method, washed with water to remove unnecessary salts, and redissolved, after which gelatin was added so that the ratio of silver to gelatin was 1:0.8. did. Next, Hypo and chloroauric acid were added and chemically aged at 55°C for 90 minutes at pAg=8.0, pH=6.0, and 4-hydroxy-6-methyl-1,
After adding 3,3a,7-tetrazaindene as a stabilizer, the following sensitizing dye (Chemical formula 11) was added, and further an antifoggant, a surfactant, and a hardening agent were added to prepare a finished emulsion. This was applied to PE-laminated RC paper in an amount of 2.5 g per square meter in terms of silver nitrate.

[0058]

[Chemical formula 11]

The resulting sample was exposed for 10-5 seconds using a xenon flash lamp through a 633 nm interference filter and a step wedge, and developed in an automatic processor using a conventional high-temperature rapid processing developer.

Next, the density of each step of this step wedge exposed sample was measured, and a normal characteristic curve was obtained.
The relative exposure amount required to obtain a reflection density of 1.0 was determined. Table 2 shows the measurement results of sensitivity, fog, and silver halide grain size for each emulsion. The sensitivity value is based on emulsion No. The fog is expressed as a relative value when the sensitivity of 1 is set to 100, and the fog is expressed as the reflection density of the unexposed area. Also,
The silver halide grain size was measured in the same manner as in Example 1, and the units of numerical values shown in the table are μm.

[0061]

[Table 2]

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

[0063]

Effects of the Invention: By the method of producing a silver halide emulsion using the novel thioether compound of the present invention, it is possible to easily obtain a silver halide emulsion with large grains, and it also has excellent characteristics of high sensitivity and low fog. It is possible to obtain a silver halide photographic emulsion having the following properties.

Claims (1)

[Claims] 1. A method for producing a silver halide photographic emulsion, which comprises using a compound represented by the following general formula 1. [Formula, R1 is H, an alkyl group, or an aryl group,
R2 represents OH or chemical formula 2, and R3 represents an alkylene group. Further, n represents an integer from 1 to 3. embedded image R4 and R5 represent H or an alkyl group. ]