JPH07134348A - Production of silver halide emulsion - Google Patents

Abstract

PURPOSE:To prevent a soln. of photographic additive from being deposited or decomposed, to further suppress its foaming, to shorten the preparing time and to obtain a dispersion excellent in aging stability by dispersing a combination of the highly dispersible additive and polyalkylene oxide block copolymer. CONSTITUTION:A substantially water-insoluble photographic additive is dissolved in a soln. obtained by admixing a surfactant having a group such as -SO3<-> and -OSO3<-> as a hydrophilic group with an org. solvent belonging to alcohols, and the obtained soln. is dripped into water to reprecipitate. Another photographic additive highly dispersible in water and a specified polyalkylene oxide block copolymer are added to the water and dispersed by a dispersing machine, and the obtained dispersion is added to a silver halide emulsion. Since at least one hydrophilic group and at least one lipophilic group are combined in the block copolymer, the copolymer acts as a surfactant.

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.

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 or decomposing, further suppressing foaming, shortening the preparation time, and stabilizing with time. The object of the present invention is to provide a manufacturing method which is an excellent dispersion.

[0009]

The present inventor has diligently studied this problem and, as a result, at the time of dispersion, a photographic additive having good dispersibility in water and a polyalkylene oxide copolymer are allowed to coexist so that the foaming property is improved. The present invention has been accomplished by discovering the fact that the above phenomenon is significantly suppressed and the dispersion of the hardly dispersible substance is promoted.

[0010] That is, the object of the present invention, the organic solvent belonging to the alcohol, -SO ₃ as the hydrophilic group ^-, -O
SO 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 represented below are added to water, dispersed by a disperser, and the resulting dispersion is added to a silver halide emulsion. This is achieved by the method for producing a characteristic 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 and 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. A .pm stirrer is used. 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.

Explaining the present invention in more detail, the substantially water-insoluble photographic additives that can be used in the present invention are solid additives, and specifically include the following. . 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 additive added to the silver halide emulsion cannot be uniquely determined depending on the kind of the additive 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 excluding anionic dyes. For example, the following compound (dye A) may be mentioned.

[0021]

[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) may be mentioned.

[0025]

[Chemical 2]

[0026]

[Chemical 3]

In the present invention, a solution prepared by adding and mixing a surfactant having a group of —SO ₃ ⁻ or —OSO ₃ ⁻ as a hydrophilic group to an organic solvent belonging to alcohols means the type of organic solvent and 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

The polyalkylene oxide block copolymer is widely known as a nonionic surfactant, and acts 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 one of the 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)

[0033]

[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)

[0038]

[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 based on 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, the compound represented by the above general formula (I) is preferable, and it is commercially available as Pluronic R manufactured by BASF.

Of the pluronic R, those having an ethylene oxide portion ratio of 30% or less are preferable, those of 20% or less are more preferable, and those of 5% or more and 15% or less are particularly preferable.

Examples of preferable compounds are compounds shown in Table 1.

[0043]

[Table 1]

In the silver halide emulsion used in the present invention, any of silver bromide, silver iodobromide, silver iodochlorobromide, silver chlorobromide, silver chloride and the like 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, etc. 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. coexist. 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.

As the binder used in the silver halide emulsion of the present invention, gelatin is preferable, 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 a method for producing a silver halide emulsion in the present invention, first, for example, a weighed organic solvent is put in a tank, a surfactant is added thereto, and stirring and dissolution are carried out 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 about 1: 5 to 2: 5, and the ratio of the diameter of the turbine blade and the gap between the bottom of the tank and the turbine blade. Is about 2: 1 to 1: 1 and the ratio of the turbine blade diameter to the stationary liquid depth in the tank is 1: 1 to 1: 1.
It is preferable to set it to about 1: 3. However, in this case, the stirring blade is not limited to the turbine blade, and may be a paddle blade, a propeller blade, a dissolver blade, or the like. 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, stirring is stopped, the temperature is cooled to 40 to 50 ° C., and the dissolved solution is dropped into water under stirring to recrystallize. In that case, a dissolver blade is used as the stirring blade. Recrystallization means that a photographic additive dissolved in an organic solvent, which is a good solvent, is added to water, which is a poor solvent, to be in a concentration state of solubility or higher (saturation concentration or higher) and crystallized.

Next, the organic solvent, the wetting agent, the dispersant, and other photographic additive (s) having a good dispersibility and a polyalkylene oxide block copolymer are added to the aqueous solution at high speed. The dispersion is carried out with a stirrer. In that case, one of the other photographic additives having good dispersibility is a photographic spectral sensitizing dye belonging to the anionic cyanine dyes.

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

[0053]

[Chemical 6]

[0054]

[Chemical 7]

As described above, a dye having a similar molecular structure and good dispersibility as described above, and a polyalkylene oxide block copolymer and a substantially water-insoluble dye are allowed to coexist and are dispersed, thereby making it difficult to disperse. Dispersion is promoted.

Needless to say, a photographic additive having good dispersibility can be added simultaneously with a photographic additive that is substantially insoluble in water. The high-speed stirrer as the disperser has been described above, but the stirring conditions are such that the dispersing time is 60 to 180 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.

[0057]

EXAMPLE One example of the present invention will be described. However, the present invention is not limited to this embodiment. 10 g of benzyl alcohol as an organic solvent belonging to alcohols
And a surfactant D having a group of —SO ₃ as a hydrophilic group; 0.8 g of triethylamine 0.1 as a small amount of a base.
g and 0.1 g of acetic acid as an acid were added to the solution under stirring at room temperature to prepare a solution, and the above dye A: 1.59 g was added to the solution as a water-insoluble photographic additive. The solution was heated and dissolved at 10 ° C for 10 minutes to prepare a solution, and after complete dissolution, stirring was stopped and the solution was cooled to 50 ° C. The solution was dropped into water and the recrystallized particles were dispersed as follows.

Comparative Example-1 The above solution was added dropwise to 500 ml of water for 10 minutes to recrystallize it, the pH was adjusted to 7, and dispersion was carried out at 50 ° C for 120 minutes with a high speed stirrer 3000 rpm. However, it could not be dispersed as a result.

Comparative Example-2 The above-mentioned solution was added dropwise to 500 ml of a 2 w% gelatin aqueous solution for 10 minutes to recrystallize the solution, and the pH was adjusted to 7 to 120 at 50 ° C.
Dispersed for minutes. As a result, dispersion was not possible and foaming was large.

Comparative Example 3 The above-mentioned solution was added dropwise to 500 ml of water for 10 minutes for recrystallization, and 8.12 g of the above-mentioned dye B as a photographic additive having good dispersibility in the liquid. 0.3 g of C was added to adjust the pH to 7, then 3,000 r.
When dispersion was performed at pm, it took 120 minutes and 1 μm
It could be dispersed in the following particles. The volume of the dispersion liquid after dispersion was about 1000 ml.

Example 1 The above solution was added dropwise to 500 ml of water for 10 minutes to recrystallize, and 8.12 g of dye B and dye C as a photographic additive having good dispersibility were added to the solution. Add 0.3 g, and then add 0.1 g of Pluronic 31R1 as a polyalkylene oxide block copolymer, adjust to pH 7, and then disperse with a high speed stirrer at 3000 rpm to obtain particles of 1 μm or less in 80 minutes. Could be dispersed. The volume of the dispersion after dispersion was about 550 ml, which was almost unchanged from the original volume.

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 The same effect as in Example-1 was obtained except that Pluronic 25R2 or Pluronic 17R2 was used as the polyalkylene oxide block copolymer.

[0064]

As described above, according to the method for producing a silver halide emulsion of the present invention, by dispersing in combination with an additive having a good dispersibility and a polyalkylene oxide block copolymer, the conventional dispersibility is poor and a silver halide is obtained. The dispersion time could be remarkably reduced although it could not be added or it took a very long time to disperse.

Further, it is possible to produce a stable silver halide emulsion without coating failure without leaving coarse particles in the dispersion of recrystallized particles, without causing agglomerates and breaking the emulsion. .

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, leading to improvement in productivity.

Further, since the organic solvent and the surfactant could be drastically reduced to dissolve 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. An organic solvent belonging to alcohols is hydrophilic.
-SO as a functional group₃ ^-, -OSO₃ ^-A world with a group
Substantially water-insoluble in the solution mixed with surfactant
Dissolve the photographic additives and drop the resulting solution into water.
After being reprecipitated, it has good dispersibility in water.
Photographic additives and polyalkylene oxides shown below.
Cide copolymer was added and dispersed by a disperser to obtain
Characterized by adding the resulting dispersion to 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)_jOr 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 bond
Unit LAO2, LOL; Lipophilic alkylene oxide block bond
Unit i = 2 j = 1 or 2 Each block-bonding unit is 4 of the block copolymer.
-96% by weight PAO-1 has a molecular weight of 760 to 18000, PAO-2 has a molecular weight of 1000 to 30000, PAO-3 has a molecular weight of 1100 to 60000, and PAO-4 has a molecular weight of 1100 to 50000.