JPH07175146A - Production of silver halide emulsion - Google Patents

Abstract

PURPOSE:To obtain such a dispersion liquid of a photographic additive that precipitation or decomposition is prevented, foaming is suppressed, a short time is required for controlling, and excellent stability with time is obtd. by allowing polyalkyleneoxide copolymers to be present together with a photographic additive having good dispersibility with water. CONSTITUTION:A photographic additive having good dispersibility with water is dispersed to obtain a dispersion liquid. As for the photographic additive, anion-base cyanine dyes are used. Or, a soln. is prepared by at least partly dissolving a surfactant having groups such as-SO3-and-OSO3-as hydrophilic groups in an alcohol org. solvent, and then dissolving a photographic additive substantially insoluble with water in the obtd. soln. As for the photographic additive insoluble with water, cyanine dyes except for anion base dies are used. Then the obtd. soln. and polyalkylene oxide copolymers are added to the dispersion liquid, and the obtd. mixture is treated in a dispersing machine to obtain a mixture dispersion liquid. Then the mixture dispersion liquid is mixed with a silver halide emulsion.

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. In particular, the present invention relates to a method of obtaining a desired photographic performance by dissolving a substantially water-insoluble photographic additive in a small amount of a mixed solution of an organic solvent and a surfactant and adding it to a silver halide emulsion.

[0002]

2. Description of the Related Art Conventionally, a method for adding various water-insoluble photographic additives to a silver halide photographic emulsion is to dissolve the photographic additives in an organic solvent and prepare an aqueous solution containing water or an anionic surfactant. Method (for example, JP-A-50)
-11419) or a photographic additive thereof dissolved in an organic solvent and added to an aqueous solution or hydrophilic colloid solution containing an aqueous binder and dispersed (for example, U.S. Pat. No. 3,788,857; 3,660,
No. 101, JP-B-49-46416, JP-A-49-128725), or a method of adding the photographic additive by dissolving it in a mixed solution of an organic solvent and a surfactant (JP-A-2). -15251, JP-A-2-152
No. 52, Japanese Unexamined Patent Publication No. 2-23332, Japanese Unexamined Patent Publication No. 2-
No. 135438).

[0003]

However, in these methods, the method of adding an organic solvent solution in which a photographic additive is dissolved into water or an aqueous solution containing an anionic surfactant is Crystallization or agglomeration occurs, and the agglomerates are not dispersed depending on the photographic additive, so coarse crystals (20 to 50 μm) remain, and when this is added to silver halide, it is used for photographic applications such as spectral sensitizers. Since the time required for the additives to be adsorbed on the silver halide becomes long, the photographic sensitivity cannot be obtained within a short time, and even if such an emulsion is coated, coating failure is likely to occur due to the precipitates and the like. There was a problem.

Further, in the method of adding and dispersing a solution of a photographic additive dissolved in an organic solvent in an aqueous solution containing an aqueous binder or a hydrophilic colloid, recrystallization occurs when the solution is added as described above. Since the binder solution or hydrocolloid has a high viscosity, the dispersion efficiency is good, but the power required for the dispersion is large. However, there is a problem that is likely to occur.

In order to solve the above problems, the present applicant first
-SO substantially additive for water-insoluble photo organic solvent belonging to the alcohol, as the hydrophilic group ₃ ^-, -OSO ₃
^- obtained by dissolving in a solution was added and mixed a surfactant having a group, the silver halide and the resulting solution, the manufacturing method and a method of silver halide emulsion comprising adding to the emulsion We have proposed a method for producing a silver halide emulsion characterized in that a small amount of a base or a base and an acid are added to a mixed solution to dissolve a substantially water-insoluble photographic additive.

Although these inventions are excellent methods, depending on the kind of the photographic additives, when a solution in which the photographic additives are dissolved is dripped into water to reprecipitate, the resulting precipitate is In some cases, it was not dispersed in water or an aqueous solution containing an aqueous binder and a hydrocolloid.

Furthermore, the applicants belong to the alcohol group
-SO as a hydrophilic group in an organic solvent^3-, -OSO
^3-In a solution mixed with a surfactant containing
, A substantially water-insoluble photographic additive is dissolved in
The dissolved solution was dropped into water to reprecipitate, and
Add other photographic additives that have good dispersibility in water,
Disperse with a disperser, and obtain the resulting dispersion in a silver halide emulsion.
Method for producing silver halide emulsion characterized by addition
Method and photographic addition with good dispersibility in water
After dispersing the agent with a disperser, alcohol is added to the dispersion.
-SO as a hydrophilic group in an organic solvent belonging to the class₃ ^-,-
OSO₃ ^-Of a mixed solution of surfactants containing
A substantially water-insoluble photographic additive was dissolved in the liquid.
Was added dropwise and dispersed with a disperser to obtain a silver halide dispersion.
Preparation of silver halide emulsion characterized by being added to the emulsion
A manufacturing method was proposed. These methods are even better
However, with other photographic additives with good dispersibility in water
In the step of dispersing them together, -S is used as the hydrophilic group.
O₃ ^-, -OSO ₃ ^-Coexist with a surfactant having a group
Foaming caused by a large liquid surface
Was able to be suppressed considerably, but fine foaming caught in the liquid
It was still insufficient in terms of suppressing Because of this
In addition, the preparation time cannot be shortened, and the volume increases due to foaming.
Can be prepared at once in a constant scale plant for
The drawback is that the quantity is limited and the manufacturing scale cannot be improved.
Had.

[0008] The present applicant further organic solvent belonging to the alcohol, -SO ₃ as the hydrophilic group ^-, -OS
O ₃ ^- in the solution was added a mixture of a surfactant having a composed group, after substantially dissolving the additives in the water-insoluble photographic, and reprecipitated by dropwise addition of the resulting solution in water, the Other photographic additives having good dispersibility in water and polyalkylene oxide copolymer shown below are added to water.
A method for producing a silver halide emulsion was proposed, which comprises dispersing with a disperser and adding the obtained dispersion to a silver halide emulsion (Japanese Patent Application No. 5-278610). Polyalkylene oxide block copolymer PAO-1 LAO1-HAO1-LAO1 PAO-2 HAO2-LAO2-HAO2 PAO-3 (H-HAO3) _i- LOL- (HAO3-H) _j PAO-4 (H-LAO4) _i- HOL- (LAO4-H) _j here LAO1, LAO4; Terminal lipophilic alkylene oxide block unit HAO2, HAO3; Terminal hydrophilic alkylene oxide block unit HAO1, HOL; Hydrophilic alkylene oxide block binding unit LAO2, LOL; Lipophilic alkylene oxide block binding unit i = 2 j = 1 or 2 The individual block-bonding units are 4 of the block copolymer.
-96 wt% PAO-1 has a molecular weight of 760 to 18,000 PAO-2 has a molecular weight of 1000 to 30000 PAO-3 has a molecular weight of 1100 to 60,000 PAO-4 has a molecular weight of 1100 to 50000

This method is a more excellent method. However, depending on the type of photographic additive, when a solution in which the photographic additive is dissolved is dropped into water for reprecipitation, the precipitate is water. Alternatively, some were not dispersed in an aqueous solution containing an aqueous binder and a hydrocolloid.

Furthermore, it has been desired to further reduce the preparation time.

The object of the present invention is to solve the above problems and to prevent the solution of the photographic additive added to the silver halide emulsion from precipitating and decomposing, thereby further suppressing foaming, shortening the preparation time, and improving the stability with time. The object of the present invention is to provide a manufacturing method which is an excellent dispersion.

[0012]

Means for Solving the Problems As a result of diligent study on this problem, the present inventor has found that upon dispersion, a photographic additive having good dispersibility in water coexists as a dispersion in a dispersion liquid, and The present invention was accomplished by discovering the fact that the coexistence of a polyalkylene oxide copolymer promotes the dispersion of a hardly dispersible substance.

That is, the above-mentioned object of the present invention is to obtain a dispersion by dispersing a photographic additive having good dispersibility in water, in an organic solvent belonging to alcohols as a hydrophilic group.
Another step of dissolving a substantially water-insoluble photographic additive in a solution in which a surfactant having a group consisting of SO ₃ and —OSO ₃ — is dissolved to obtain a solution, in the above dispersion liquid And a step of treating the mixture obtained by adding the above solution and the polyalkylene oxide copolymer with a disperser to obtain a mixture dispersion, and mixing the mixture dispersion with a silver halide emulsion. And a method for producing a silver halide emulsion.

Polyalkylene oxide block copolymer PAO-1 LAO1-HAO1-LAO1 PAO-2 HAO2-LAO2-HAO2 PAO-3 (H-HAO3) _i -LOL- (HAO3-H) _j PAO-4 (H-LAO4) _i −HOL − (LAO4 −H) _j where LAO1, LAO4; terminal lipophilic alkylene oxide block unit HAO2, HAO3; terminal hydrophilic alkylene oxide block unit HAO1, HOL; hydrophilic alkylene oxide block binding unit LAO2, LOL; parent Oily alkylene oxide block-bonding unit i = 2 j = 1 or 2 Each block-bonding unit is 4 of the block copolymer.
-96 wt% PAO-1 has a molecular weight of 760 to 18,000 PAO-2 has a molecular weight of 1000 to 30000 PAO-3 has a molecular weight of 1100 to 60,000 PAO-4 has a molecular weight of 1100 to 50000

In the present invention, to disperse a photographic additive having good dispersibility in water in water means that an organic solvent is not used, a wetting agent or a dispersant is not present in an aqueous solution system, and mechanical dispersion is performed. A photographic additive that can be dispersed in

In the present invention, to disperse with a disperser means, for example, as shown in FIG. 1, a liquid 1 to be dispersed is put in a tank 1 and a dissolver blade 3 is provided, preferably a rotation speed of 2000 to 4000 rpm. It means to use the stirrer. As shown in FIG. 2, the dissolver blade 3 has a large number of sets of vertical upward vanes 33 and vertical downward vanes 32 alternately arranged on an impeller 31.

Ratio of impeller diameter to tank inner diameter 1:
A ratio of about 5 to 2: 5, a ratio of the diameter of the impeller to the distance between the tank bottom and the impeller of about 2: 1 to 1: 1 and a ratio of the diameter of the impeller to the depth of the stationary liquid in the tank of about 1: 3 are preferable.

The present invention will be described in more detail. The substantially water-insoluble photographic additives that can be used in the present invention are solid additives, specifically, the following ones. . Examples thereof include spectral sensitizing dyes, antifoggants, color couplers, dyes, sensitizers, hardeners, ultraviolet absorbers, antistatic agents, brighteners, desensitizers, developers, antifading agents, and mordants. For these additives, see RESEAR
CH DISCLOSURE vol.176 RD-17643 page 2
2-31 (December 1978).

Examples of the spectral sensitizer include methine dyes such as cyanine dyes, merocyanine dyes, hemicyanine dyes, rhodacyanine dyes, oxonol dyes, and hemioxonol dyes, and styryl dyes.
Also in these dyes, an anionic dye, for example, one sulfo group or sulfoalkyl group as a substituent, preferably 2
Dyes having more than one are effective.

As the spectral sensitizer, those described in the following other than the above publications are used. German Patent No. 929080, US Patent No. 2493748, 2
503776, 251901, 291232
No. 9, No. 3656959, No. 3672897, No. 3
694217, 4025349, 404657.
No. 2, No. 2688545, No. 2977229, No. 3
397060, 3522052, 352764.
No. 1, No. 3617293, No. 3628964, No. 3
No. 666480, No. 3672898, No. 367942
No. 8, No. 3703377, No. 3814609, No. 3
837862, 4026707, British Patent 124
2588, 1344281, 1507803
No. 4, Japanese Patent Publication No. 44-14030, No. 52-24844
No. 43-4936, No. 53-12375, JP-A No. 52-110618, No. 52-109925, and No. 50-80827.

Other than the spectral sensitizer, the following can be mentioned. That is, benzotriazole compounds, 4-thiazolidone compounds, benzophenone compounds, cinnamic acid ester compounds, butadiene compounds, benzoxazole compounds, cationic polymers, chromium salts, aldehydes, N-methylol compounds, dioxane derivatives, active vinyl compounds, active halogens. Compounds, mucohalogenates, nitroindazoles, triazoles, benzotriazoles, benzimidazoles, mercaptothiazoles, mercaptobenzothiazoles, tetraazaindenes, 5-pyrazolone couplers,
Examples thereof include pyrazolone benzimidazole couplers, acylacetamide couplers, naphthol couplers and phenol couplers.

The amount of the substantially water-insoluble photographic additives added to the silver halide emulsion cannot be unequivocally determined depending on the kind of the additives and the amount of silver halide.
It can be used in almost the same amount as that added by the conventional method.

The present invention is particularly effective when the water-insoluble photographic additive is a photographic spectral sensitizing dye belonging to cyanine dyes except anionic dyes. For example, the following compound (dye A) may be mentioned.

[0024]

[Chemical 1]

Organic solvents belonging to the alcohols used in the present invention include aliphatic saturated alcohols, aliphatic unsaturated alcohols, alicyclic alcohols, aromatic alcohols,
Although there are heterocyclic alcohols and the like, aromatic primary alcohols and halogenated alcohols are particularly preferable. For example, benzyl alcohol (C ₆ H ₅ CH ₂ OH) (hereinafter referred to as organic solvent B),
Fluorinated alcohol (HCF ₂ CF ₂ CF ₂ OH or CF ₃ CH ₂ OH) (hereinafter referred to as organic solvent C) can be used.

As the hydrophilic group used in the present invention, -S is used.
Examples of the surfactant having a group consisting of O ₃ ⁻ and —OSO ₃ ^— include an alkyl sulfate, an alkyl sulfonate, an alkyl aryl sulfonate, and a sulfosuccinate ester salt as an anionic surfactant.

For example, the following compounds (surfactant D) and (surfactant E) can be mentioned.

[0028]

[Chemical 2]

[0029]

[Chemical 3]

In the present invention, a solution in which a surfactant having a group of —SO ₃ ⁻ or —OSO ₃ ⁻ as a hydrophilic group is added to and mixed with an organic solvent belonging to alcohols means the organic solvent and the type of surfactant. The amount of the surfactant is 25 to 100% by weight with respect to the amount of the photographic additive, and the amount of the organic solvent is only the organic solvent when the two are dissolved in a mixed solution. About 1/3 to 1 / of the required amount
Weight of 2 is enough.

In the present invention, a small amount of base or base and acid may be added to the mixed solution of the organic solvent and the surfactant.

The polyalkylene oxide block copolymer used in the present invention is as follows. Polyalkylene oxide block copolymer PAO-1 LAO1-HAO1-LAO1 PAO-2 HAO2-LAO2-HAO2 PAO-3 (H-HAO3) _i- LOL- (HAO3-H) _j PAO-4 (H-LAO4) _i- HOL -(LAO4 -H) _j where LAO1, LAO4; terminal lipophilic alkylene oxide block unit HAO2, HAO3; terminal hydrophilic alkylene oxide block unit HAO1, HOL; hydrophilic alkylene oxide block bonding unit LAO2, LOL; lipophilic alkylene oxide Block binding unit i = 2 j = 1 or 2 Each block binding unit is 4 of the block copolymer.
-96 wt% PAO-1 has a molecular weight of 760 to 18,000 PAO-2 has a molecular weight of 1000 to 30000 PAO-3 has a molecular weight of 1100 to 60,000 PAO-4 has a molecular weight of 1100 to 50000

Polyalkylene oxide block copolymers are widely known as nonionic surfactants, and act as a surfactant by having at least one hydrophilic group and at least one lipophilic group bonded to each other. For a general description of block copolymer surfactants, see IR Schmolka, A Review of Block Polyme.
r Surfactants "J. Am. Oil Chem. Soc. Vol 54, No.
3, pp. 110-116, 1977 and AS Davidsoh.
n, B. Milwidsky "Synthetic Detergents" John Wiley
& Sons, NY, pp. 29-40, pp. 34-36.

The simplest polyalkylene oxide block copolymer PAO-1 is formed as follows. First, ethylene glycol and ethylene oxide are condensed to form a block repeating unit that becomes an oligomer or polymer that acts as a hydrophilic block, and the reaction is completed using 1,2-propylene oxide. The propylene oxide will be added to both sides of ethyne oxide. At this time, at least 6 repeating units of 1,2-propylene oxide are required to form a lipophilic block unit.

The structure of the polyalkylene oxide block copolymer surfactant thus obtained can be represented by the following general formula (I). General formula (I)

[0036]

[Chemical 4]

Where X and X'are 6 to 30 respectively.
0, preferably 6 to 120, Y is a value in the range of 4 to 96% by weight of the total block copolymer of hydrophilic units, 2 to 500, preferably 2 to 3
00. x, x'and y are shown as number averages.

The simplest polyalkylene oxide block copolymer PAO-2 can be prepared as follows. First, 1,2-propylene glycol and 1,2-propylene oxide are condensed to form a block repeating unit that becomes an oligomer or polymer that acts as a lipophilic block, and the reaction is completed using ethylene oxide.

Ethylene oxide is added to both ends of the 1,2-propylene oxide block unit. At this time, at least 13 1,2-propylene oxide repeating units are required to form a lipophilic block unit.

The structure of the completed polyalkylene oxide block copolymer is represented by the following general formula (II).
General formula (II)

[0041]

[Chemical 5]

Here, x ₁ is 13 to 900, preferably 13 to 490, and y and y ₁ ′ are values in the range of 4 to 96% by weight of the total weight of the block copolymer, and 1 to 500. , Preferably from 1 to 320 and shown as a number average value.

Among the polyalkylene oxide block copolymers, preferred are the compounds represented by the above-mentioned general formula (I), which are commercially available as Pluronic R manufactured by BASF.

Of the pluronic R, the proportion of ethylene oxide portion is preferably 30% or less, more preferably 20% or less, particularly preferably 5% or more and 15% or less.

Examples of preferable compounds are the compounds shown in Table 1.

[0046]

[Table 1]

In the silver halide emulsion used in the present invention, any of silver bromide, silver iodobromide, silver iodochlorobromide, silver chlorobromide, silver chloride, etc. may be used. The grain size of silver halide is not particularly limited, but is 3 μm.
The following are preferred. These silver halide emulsions can be easily prepared by the methods described in the following documents. Chimie et Physique Photographiq by P. Glafkides
ue (Published by Paul Montel, 1967), GF Duffin Pho
tograhic Emulsion Chemistry (published by The Focal Press, 1
966), by VL Zelikman et al Making and Coatin
g Photographic Emulsion (Published by The Focal Press, 196
4 years).

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 halogen salt may be a one-sided mixing method, a simultaneous mixing method,
Any combination thereof may be used. A method of forming grains in the presence of excess silver ions (so-called reverse mixing method) can also be used. As one form of the simultaneous mixing method, a method of keeping pAg constant in a liquid phase where silver halide is produced, that is, a so-called 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. Two or more kinds of silver halide emulsions formed separately may be mixed and used.

In the process of silver halide grain formation or physical ripening, even if cadmium salt, zinc salt, lead salt, thallium salt, iridium salt or its complex salt, rhodium salt or its complex salt, iron salt or iron complex salt, etc. are present together. Good. Various other additives can be used in the silver halide emulsion used in the present invention. That is, a sulfur sensitizer,
Reduction sensitizers, sensitizers such as noble metal sensitizers, stabilizers, surfactants, hardeners, thickeners, dyes, ultraviolet absorbers, antistatic agents, brighteners, desensitizers, developers , Anti-fading agents, mordants and the like can be used. Further, a coupler such as a color coupler may be dispersed in oil and used.

Regarding these additives, RESEARCH DIS
CLOSURE (RD-17643), vol.176, Page22-
31 (December 1978), THE THEORY OF THE PHOTOG
RAPHIC PROCESS (4th Ed.) TH James edition (1977, Ma
cmillan Publishing Co. Inc.) and the like.

Gelatin is preferred as the binder used in the silver halide emulsion of the present invention, but in addition to gelatin, derivative gelatin such as phthalated gelatin, albumin, agar, gum arabic, cellulose derivative, polyvinyl acetate, polyacrylamide. , Polyvinyl alcohol, etc. are used.

As the method for producing a silver halide emulsion in the present invention, first, a photographic additive (s) having good dispersibility in water without adding an organic solvent, a wetting agent and a dispersant in water may be used. Is added and dispersed by a high-speed stirrer. In this case, a photographic spectral sensitizing dye belonging to the anionic cyanine dyes is one of the photographic additives having good dispersibility in water.

Typical examples thereof include the following (Dye B) and (Dye C).

[0054]

[Chemical 6]

[0055]

[Chemical 7]

Next, the weighed organic solvent is put in another tank, the surfactant is added thereto, and the mixture is stirred and dissolved by a stirring blade under room temperature conditions. The stirring blade is a turbine blade having four blades on the stirring shaft, and the ratio of the diameter to the tank inner diameter is 1:
The ratio of the diameter of the turbine blade to the clearance between the bottom of the tank and the turbine blade is about 2: 1 to 1: 1 at about 5 to 2: 5, and the ratio of the diameter of the turbine blade to the depth of the stationary liquid in the tank is 1. : 1-1: 1
It is preferable to set it to about 3. However, in this case, the stirring blade is not limited to the turbine blade, but the paddle blade, propeller blade,
A dissolver blade or the like may be used. A magnetic stirrer can be used for small adjustments. Depending on the type of the added surfactant, a small amount of base or base and acid is added.

Next, when a stirred mixed liquid is formed, the mixed liquid is heated to 70 ° C., and then a photographic additive is added and dissolved at 70 ° C. with stirring as described above. After confirming the completely dissolved state, the stirring was stopped, the temperature was cooled to 40 to 50 ° C., the solution was added dropwise to the dispersion liquid of the photographic additive having good dispersibility in water, and the polyalkylene oxide block copolymer was further added. Is added, and the dispersion liquid dispersed by a disperser is added to the silver halide emulsion.

As described above, it is difficult to disperse a dispersion of a dye having a similar molecular structure and good dispersibility and a polyalkylene oxide block copolymer and a substantially water-insoluble dye in the coexisting state as described above. Dispersion promotes dispersion.

Needless to say, a photographic additive having good dispersibility can be added simultaneously with a photographic additive that is substantially insoluble in water. Although the high-speed stirrer as the disperser has been described above, the stirring conditions are such that the dispersing time is 30 to 120 minutes, the dispersing temperature is 50 ° C., and the pH is 6.5.
The condition of ~ 7.5 is preferable. By this dispersion, the recrystallized particles are dispersed to 1 μm or less. The solution obtained in the present invention may be directly added to the silver halide emulsion, or once mixed with the protective colloid, it may be added in a dissolved state or a gel state to obtain sufficient photographic performance. Obtainable.

[0060]

EXAMPLES Examples of the present invention will be described. However, the present invention is not limited to this embodiment.

Comparative Example-1 First, 8.12 g of the above-mentioned dye B and 0.3 g of the above-mentioned dye C as a photographic additive having good dispersibility were added to 500 ml of water and adjusted to pH 7 at a temperature of 50 ° C. Dispersion was performed with a high-speed stirrer at 3000 rpm for 30 minutes to prepare a dispersion liquid of particles of 1 μm or less. Next, 10 g of benzyl alcohol or 8 g of fluorinated alcohol as an organic solvent belonging to alcohols, 0.8 g of the above-mentioned surfactant D having a group of —SO ₃ as a hydrophilic group, 0.1 g of triethylamine as a small amount of base, and an acid. 0.1 g of acetic acid as a solvent was added to the solution under stirring at room temperature to prepare a solution, and 1.59 g of the dye A as a water-insoluble photographic additive was added to the solution and heated at 70 ° C. for 10 minutes with a magnetic stirrer. After dissolution, a solution was prepared and after complete dissolution, stirring was stopped and the solution was cooled to 50 ° C.

The solution was added dropwise to the above dispersion for 10 minutes, and it took 60 minutes with a high-speed stirrer 3000 rpm to complete the dispersion to a size of 1 μm or less at pH 7 and 50 ° C.
Further, the volume of the dispersion liquid after dispersion was about 800 ml. The preparation time was 100 minutes in total.

Comparative Example-2 A solution of the dye A described in Comparative Example-1 was added to 500 ml of water.
It is dripped for a minute to make a reprecipitate, 8.12 g of the above-mentioned dye B and 0.3 g of dye C are added as a photographic additive having good dispersibility, and Pluronic 31R1 is added as a polyalkylene oxide block copolymer. 0.
Add 1g, adjust to pH 7, then 30 with high speed stirrer
When it was dispersed at 00 rpm, it took 80 minutes to disperse the particles into particles of 1 μm or less. The volume of the dispersion after dispersion was about 550 ml. The preparation time was 90 minutes in total.

Example-1 In the same manner as in Comparative Example-1, a dispersion liquid containing the dye B and the dye C, and a solution of the dye A were prepared. The solution of Dye A was added dropwise to the dispersion containing the dispersion of Dye B and Dye C over 10 minutes, and 0.1% of Pluronic 31R1 was added as a polyalkylene oxide block copolymer.
It took 30 minutes with a high-speed stirrer of 3000 rpm to complete the dispersion by adding g and completing the dispersion to a size of 1 μm or less at pH 7 and 50 ° C. The volume of the dispersion liquid after dispersion was about 540 ml. The preparation time was 70 minutes in total.

When this was added to a silver halide emulsion and coating was carried out, no coating failure occurred and the photographic performance was excellent.

Example-2 Dispersion was performed in the same manner as in Example-1 except that Pluronic 25R2 or Pluronic 17R2 was used as the polyalkylene oxide block copolymer, and the same effect was obtained.

[0067]

As described above, according to the method for producing a silver halide emulsion of the present invention, a dispersion of additives having good dispersibility and a polyalkylene oxide block copolymer are combined and dispersed to obtain a water-insoluble photographic additive. Dispersion is promoted.

When a solution of a water-insoluble photographic additive (alcohol + surfactant + water-insoluble photographic additive) is dropped, the photographic additive having good dispersibility in water is already dispersed. Since the viscosity of the system is sufficiently high, the solution begins to disperse at the same time as it is dropped, and the dispersion is accelerated.
At this time, by allowing the polyalkylene oxide block copolymer to coexist, the foaming amount at the time of dispersion can be significantly suppressed, so that the dispersion can be completed in a very short time.

Further, since the amount of foaming at the time of dispersion can be remarkably suppressed, a large amount of dispersion can be produced at one time by a disperser of the same scale, which leads to improvement in productivity.

Further, since the organic solvent and the surfactant were able to be drastically reduced in dissolving the photographic additives, it was possible to prepare a dispersion having no precipitation and decomposition and excellent in stability over time.

[Brief description of drawings]

FIG. 1 is a schematic side view of a high-speed stirrer used for dispersion of the present invention.

FIG. 2 is a perspective view of a dissolver blade.

[Explanation of symbols]

 1 ... Tank 2 ... Liquid to be dispersed 3 ... Dissolver 31 ... Impeller 32, 33 ... Blade

Claims (1)

[Claims] 1. A step of dispersing a photographic additive having good dispersibility in water to obtain a dispersion, and an organic solvent belonging to alcohols having --SO as a hydrophilic group.
₃ , another step of dissolving a substantially water-insoluble photographic additive in a solution in which a surfactant having a group consisting of —OSO ₃ — is dissolved to obtain a solution, And a step of treating the mixture obtained by adding the solution and the polyalkylene oxide copolymer with a disperser to obtain a mixture dispersion, and mixing the mixture dispersion with a silver halide emulsion. Method for producing silver halide emulsion. Polyalkylene oxide block copolymer PAO-1 LAO1-HAO1-LAO1, PAO-2 HAO2-LAO2-HAO2, PAO-3 (H-HAO3) _i- LOL- (HAO3-H) _j or PAO-4 (H-LAO4) _i −HOL − (LAO4 −H) _j where LAO1, LAO4; terminal lipophilic alkylene oxide block unit HAO2, HAO3; terminal hydrophilic alkylene oxide block unit HAO1, HOL; hydrophilic alkylene oxide block binding unit LAO2, LOL; parent Oily alkylene oxide block-bonding unit i = 2 j = 1 or 2 Each block-bonding unit is 4 of the block copolymer.
-96 wt% PAO-1 has a molecular weight of 760 to 18,000 PAO-2 has a molecular weight of 1000 to 30000 PAO-3 has a molecular weight of 1100 to 60,000 PAO-4 has a molecular weight of 1100 to 50000