JPS61117533A - Production of silver halide photographic emulsion - Google Patents

Abstract

PURPOSE:To obtain an AgX emulsion composed of fine particles and having a monodispersing property by carrying out a pAg (EAG) control of a growing rate of a silver halide (AgX) particle in an aqueous solution of a hydrophilic colloid under a specific condition. CONSTITUTION:In a process for producing the AgX emulsion by adding an aqueous solutions of the water soluble silver salt and the water soluble halide into an aqueous solution of the hydrophilic colloid by means of a double jet method, the silver salt solution and the halide solution are added to the aqueous solution of the hydrophilic colloid so as not to exceed the growing rate of the AgX particles to a critical growing rate thereof, and so as to maintain the EAG value of the aqueous solution of the hydrophilic colloid to a constant value within 140-200mV ranges for 1/30-1/5th the whole addition time from a start of addition, and also so as to maintain the EAG value to a constant value within 80-140mV ranges fro at least a half of the whole additional time. By controlling the additional rate as mentioned above, the fine particles of AgX having 0.1-0.4mum particle size are obtd. in the monodispersing state, and a quantum efficiency of the titled emulsion is improved, thereby obtaining the titled emulsion having a high sensitivity and a high contrast, and depressing a fog of the obtd. image.

Description

Detailed Description of the Invention [Field of Industrial Application] 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 containing highly monodisperse silver halide grains. .
[Prior art] In order to obtain a photographic emulsion that has high sensitivity compared to the average grain size, high contrast, and low fog, the quantum efficiency of the silver halide grains constituting the emulsion is increased, and their monodispersity is improved. Proceedings of the Tokyo Symposium 1980 sponsored by the Photographic Society of Japan 1 Interactions Between Lights and Aerials for Photographic Applicants.

(Interactions between lig
ht and materials for photo
graphic applications) on page 9. According to this research, it is predicted that creating a monodisperse emulsion by narrowing the particle size distribution will be effective in improving quantum efficiency. In addition, in order to sensitize silver halide emulsions, in a process called chemical sensitization, monodisperse It seems reasonable to infer that emulsions would be advantageous.

For this reason, in recent years, much research has been conducted on manufacturing techniques for monodisperse silver halide emulsions and the design of photosensitive materials using monodisperse emulsions. That is, monodisperse silver halide grains having a desired size can be obtained by adding a water-soluble silver salt and a water-soluble halide by a double jet method while controlling PAf and pH.

In addition, a highly monodisperse silver saponide emulsion is disclosed in Japanese Patent Application Laid-open No. 1)8.
The method described in Japanese Patent No. 54-48521 can be applied. In a preferred embodiment of the method, a potassium iodobromide-gelatin aqueous solution and an ammoniacal nitric acid aqueous solution are added to an aqueous gelatin solution containing silver oxide phase grains at a rate of addition as a function of time. Manufactured by a method. In this case, a technique is known in which a highly monodisperse silver halide emulsion can be obtained by appropriately selecting the addition rate as a time function, pH%, PAt%, temperature, etc.

[Problem to be solved by the invention]

According to the known silver halide emulsion manufacturing method as described above, a good monodisperse emulsion can be obtained within the average grain size range. In systems consisting of particles, it was not always possible to obtain a satisfactory monodisperse state.

The present invention aims to provide a method for producing a silver oxide photographic emulsion which is composed of the above-mentioned fine grains and has a high monodispersity.

[Means for solving problems]

The present inventors have determined the conditions such as PAf value, pH value, temperature, etc. in the silver decagenide grain formation system by the double jet method,
Alternatively, as a result of a detailed study of the addition rate of silver salts and halides, it was found that the growth rate of silver halide grains in a water-soluble silver salt aqueous solution and a silver halide aqueous solution in a hydrophilic colloid aqueous solution did not exceed the critical growth rate. , and start mixing.Add all the ingredients at once. The EAg value of the hydrophilic colloid aqueous solution within a time corresponding to 140 mV to 200 mV
The EA is substantially maintained at a constant value set within the range of mV, and then the EA is maintained at a constant value set within the range of mV, and thereafter the EA is maintained at a constant value set within the range of
High molecular weight particles having a relatively fine average particle size by adding at a rate that substantially maintains the g value at a constant value set within the range of 80 mV to 140 mV.

It was discovered that a pore-scattering agent could be obtained, leading to the present invention.

In the present invention, the expression that the growth rate of silver halide grains does not exceed a critical growth rate means that a supersaturation concentration at which new nuclei of silver halide grains are generated is not provided.

The critical growth rate here is determined by actually forming crystals in an actual system by changing the addition rate of various ions and halogen ions, taking samples from the reaction vessel, and observing them under an electron microscope. It can be determined by checking the occurrence of.

In addition, the EAg value is calculated using complex potential, which is a well-known concept among those skilled in the art.
It is shown as a value measured using an Agcl reference electrode.

The EAg values shown below are values measured using the electrode disclosed in JP-A-57-197534.

As mentioned above, the method of the present invention is characterized by setting the addition rate of the copper salt aqueous solution and the halide aqueous solution within a range that suppresses the growth rate of silver halide grains below the critical growth rate, and at the same time, the addition timing of the internal solution is divided into at least two periods, the first addition period corresponding to the total addition time from the start of addition, or the addition time, and the second addition period corresponding to at least the total addition time following that. The purpose is to form particles while maintaining a constant EAg for different periods.

The above total addition time greatly affects the final grain size of the silver halide grains formed, and the average long side grain size of the grains ranges from 0.1 to 0.
．． When the objective is to produce relatively mechanical particles of about 4 μm, it is preferable to set the time to 20 to 150 minutes. For example, if the total addition time is taken as minutes, the addition period for box 1 is between 3 and 18 minutes, and the second addition period is at least 45 minutes.
.

The first addition period requires substantially maintaining a constant EAg set within the range of 140 mV to 200 mV. E) The region of 1200 mV or more is close to the potential points of silver ions, halide ions, etc., and it is extremely difficult to keep the EAg value of the hydrophilic colloid aqueous solution constant.

If the EAg value is still higher, for example, 400 mV or more, silver halide grains with high capri will be produced due to photographic characteristics, making it impossible to put it to practical use.

In addition, if the EAg value is less than 130 mV, twin crystals will occur prominently, resulting in a high capri emulsion, which is difficult to put into practical use. Must be maintained substantially at that value. If the EAg value during this period is 150yyxV, many tabular crystals and twin crystals will occur, resulting in an emulsion with high fog and low contrast, which is undesirable in terms of photographic properties. Furthermore, if the EAg value is lower than 70 mV, monodispersity decreases, tabular crystals and twin crystals occur, resulting in an emulsion with low sensitivity and contrast, making it difficult to put it to practical use.

Here, keeping the EAg value constant means controlling the set EAg value to be constant.

As a means to more strictly control the EAg value,
Iron is added per unit time by dividing the aqueous solution of a water-soluble halide (halogen ion solution) into two parts and adding an aqueous solution of a water-soluble silver salt (silver ion solution) along one side. Halide ions with approximately the same molar concentration as the ions are added to produce silver ions, and the other halide ion solution is adjusted so that the amount of change in EAr is sufficiently small relative to the change in EAg value. , chloride ions and bromide ions are preferably added to control the EAr value.

In the method of the present invention, the silver ion solution and the halide ion solution are mixed by a double jet method. The higher the value, the better. Kazuma partly due to poor mixing efficiency?
This is because an increase or decrease in the value occurs, changing the monodisperse emulsion characteristics.

In the present invention, as the hydrophilic colloid, water-soluble polymers such as natural or synthetic polymers such as gelatin and polyvinyl alcohol can be used alone or in combination.

The total amount of hydrophilic colloid is not particularly specified, but 1 t of solution
It is preferable that it is in the range of 0.5 to 100 t.

A typical example of the water-soluble silver salt 9 aqueous solution used in the present invention is a silver nitrate aqueous solution.

Further, examples of aqueous solutions and liquids of water-soluble halides include aqueous solutions of potassium iodide, sodium iodide, potassium bromide, sodium bromide, ammonium bromide, potassium chloride, and sodium chloride.

In the present invention, the concentrations of the water-soluble copper salt aqueous solution and the water-soluble halide aqueous solution are not particularly specified, but are 0.5 to 4.
．． 0 mol/L is preferred.

The average grain size of the silver halide grains in the agent is preferably 0,
The emulsion is a monodisperse emulsion of 5 μm or less, more preferably 0.15 to 0.40 μm.

In this case, (standard deviation of particle size)/(average particle size) x 100
The coefficient of variation expressed by is 15% or less, especially 10% or less.

Note that if the coefficient of variation exceeds 20%, it becomes difficult to obtain desirable performance in terms of photographic characteristics. This seems to be related to physical ripening and chemical sensitization after particle preparation, but the details have not been clarified.

Furthermore, when the average particle size exceeds 0.4 μm, the maximum density decreases and the contrast also decreases.

4 The crystal habit is usually cubic, but particles with apparently rounded corners may be formed.

The method of the present invention can be carried out on emulsions using any of the ammonia method, neutral method, and acid method, but especially the acid method!
It is preferable to use

The emulsion formed by the method of the present invention can be desalted of process-soluble salts by various known methods such as a coagulation washing method using a coagulant.

Furthermore, the silver halide emulsion produced by the method of the present invention can be sensitized by sulfur sensitization, selenium sensitization, metal sensitization using gold, platinum, iridium, etc., reduction sensitization, or any of the known adhesive sensitization methods combining these sensitization methods. Chemical sensitization can be carried out by a sensitization method, or optical sensitization can be carried out by adding various known optical sensitizers such as cyanine and merocyanine.

The emulsion produced by the method of the present invention may further contain various additives used in silver halide emulsions, such as various known inhibitors such as azaindenes, triazoles, thiazoles, and tetrazoles, and various known hardeners and spreading agents. Can be added arbitrarily.

To prepare a light-sensitive material using the emulsion according to the present invention, it is necessary to coat and dry the emulsion on a known support such as photographic base paper, resin-covered paper, synthetic paper, cellulose, acetate film, polyester film, glass plate, etc. good.

EXAMPLES The present invention will be specifically explained below with reference to Examples.

[Example 1] Prepare liquid A, liquid B, and C# according to the following formulations, and measure the Eht values (hereinafter referred to as first and second EAp) in the first and second addition periods.
Silver chlorobromide emulsions N[L1 to N[L9] having a AgC1:AgBr molar ratio of 70:30 were prepared by mixing the emulsions while maintaining the respective values shown in Table 1.

Nal~NadFi in the emulsion is a sample according to the present invention, N
a5-Na9 are control samples made with EAg values outside the range of the present invention.

[Solution A]

Ossein gelatin 17t polyisopropylene-polyethyleneoxy.

Disuccinic acid ester sodium salt 5-10%
Ethanol solution distilled water 1280CC
[Solution B] Silver nitrate 170v distilled water 410 - [Solution C] Sodium chloride 40.9f Potassium bromide 35.7f Polyisopropylene-polyethyleneoxydisuccinate sodium salt 10% ethanol solution 3-Ossein gelatin 11f Distilled water
407-Sodium chloride was added to the solution A so as to reach the first addition EAg value shown in light 1 after keeping the solution A at 40°C.

Next, the solution B was prepared by the double jet method using the mixing agitator described in JP-A-57-92523 and JP-A-57-92524.
and molten@C were added.

A metal silver electrode and a double-junction type saturated Ag/Agcl comparison electrode were used to measure the EAg value (the electrode configuration was based on the double-junction type saturated Ag/Agcl reference electrode disclosed in JP-A-57-197534). used.).

Further, a variable flow rate roller-chave metering pump was used to add solutions B and C.

In these cases, the addition time differs depending on each sample because the addition time is determined empirically so that the side length average grain size of the prepared silver halide grains is almost the same. This is because of this.

Furthermore, during the addition, the emulsion is sampled and observed using an electron microscope to ensure that no new particles are generated within the system, thereby confirming that the amount added does not exceed the critical growth rate within the system.

During the addition, the pH value in the system was controlled with a 3% nitric acid aqueous solution to keep it constant at 3.0. The critical growth rate should be maintained as fast as possible within a range that does not cause debris and should not fall outside the specified EAg value @ 1 k
Table 2 (Ugly 1.2) shows the total addition time of 80 minutes.
．． 3.5.6.7 ,) 69 minutes version is on the 3rd floor (floor 4)
The one with 98 minutes is the 4th dragon (N[L8), and the one with 49 minutes is the 5th dragon.
It was changed over time as shown in (N[L9).

From the first EAt value to the second EAg value, EAg was added using a 3 mol/l aqueous sodium chloride solution 5 minutes after the start of addition.
Changed the value. At that time, the EAg value increases +14-7
In this case, a 1% A=/l silver nitrate aqueous solution was used.

In each case, the changes were all completed within 1 minute and stabilized at the second EAg value.

To keep the EAg value constant, 3 mol/l of sodium chloride = 1
5- Table 2 Addition flow rate for 80 minutes of addition time (Sample N [L 1.2.3.5.6.7) Table 3 Addition flow rate for 69 minutes of addition time (Sample N [L4) Table 4 Addition time Addition flow rate for 98 minutes (sample Nα8) Table 5 Addition flow rate for addition time 49 minutes (sample Nα9) The sample grades 1 to Na9 obtained in this way were analyzed using an electron microscope to determine the side length average grain size, coefficient of variation, and twin occurrence rate. was measured and calculated.

The particle size distribution coefficient was calculated according to the following formula (1).

Further, the degree of occurrence of twins was calculated according to the following formula (2).

In this example, the normal crystal was a (100) cubic crystal.

Average particle size, particle size distribution coefficient, twin occurrence rate of each sample - River Table 6 As shown in Table 6, the average particle size of samples 1m1 to 9 was 0.25±
001μ, and an emulsion with approximately the same average grain size could be prepared. Samples Nal~4 in the present invention are comparative samples Nal~9
On the other hand, the grain size distribution was narrow, indicating that the emulsion was a monodisperse emulsion with little occurrence of twins.

Next, these emulsions were subjected to total sulfur sensitization, and conditions for this chemical sensitization were selected so that the sensitivity of each emulsion was approximately the same. After chemical sensitization, 6-methyl-4-hydroxy-1,3゜3a,7-titrazaindene was added as a stabilizer, and 1-(β-hydroxyethyl)-3-phenyl-5-(( Adding 150 q of 3-γ-sulfopropyl-α-benzoxazolindene)-ethylidene cothiohydantoin per mole of Ag;
After optical sensitization, saponin was added as a coating aid and formalin was added as a hardening agent until the amount of silver was 4. Of/lr? It was coated on a polyethylene terephthalate film and dried.

Using an optical wedge, the sample thus obtained was subjected to stepwise exposure to white light, and then treated with a developer having the composition shown in Table 7.
It was developed at 20'°C.

The results are shown in Table 8.

Table 7 Developer formulation EDTA-2Na 2
t5-methylbenzotriazole 1f1-
Phenyl-5-mercaptotetrazole 0.369K
Amount to make OHpH = 10.4 - 22 = 2 SOs
253fKBr
13f Hydroquinone 80fKzCOs
40f diethylene glycol 10011-phenyl-4,4-dimethyl-3-pyrazolidone 1.42
Finish to 1 t with water. pH = 10.4. Dilute 1 t of the above solution with 3 t of water and use.

Table 8 *1 Relative sensitivity when 1., i., A-2, calculated as the reciprocal of the amount of light required to produce an image density of 2.5, is 100.

*2 Gradient of the straight line connecting the points from density 1.0 to density 2.5 on the photographic characteristic curve with respect to the exposure axis 0 Sample H prepared by the method of the present invention as shown in Table 8
cL1.2.3.4 is the comparison sample Na 5.6.7.8.
It can be seen that the emulsion has a low capri compared to 9 and has a high contrast.

<Example 2> Next, we will show an example in which the silver halide emulsion production method according to the present invention can obtain a low capri high contrast emulsion even by changing the halide composition.
The amounts of aluminum, potassium bromide and distilled water were changed as shown in Table 9.

Table 9 one] Next, AgC2Br was prepared in the same manner as in Example 1.

Here, the first EAg values are all 160 mV, the second E
All Ar values are 120 mV, which is the value based on the present invention.
Further, the first EAg time was also all set to 5 minutes. Also, the total addition time is 10:60 minutes (addition flow i Table 10), N
α11: 69 minutes (Additional flow rate Table 11) Nα12 and Nα13: 80 minutes (Additional flow rate Table 2) Floor 14:
89 minutes (addition flow rate Table 12), Nα15: 98 minutes (
Addition flow rate No. 13), N[Li2: 117 minutes (Addition flow rate m14 table).

Table 10 Addition flow rate for addition time 60 minutes (sample ugliness 10) Table 11 Addition flow rate for addition time 69 minutes l・(sample r+a
11. ) Table 12 Addition flow rate for addition time 89 minutes (Sample No. 14) Table 13 Addition flow rate for addition time 98 minutes l (Sample N [Li
2) Table 14 Addition flow rate for addition time 117 minutes (Sample N [Li
2) The average particle size, particle size distribution, and twin occurrence rate, which were measured and calculated in the same manner as in Example 1, are shown in Table 15.

Table 15 As shown in Table 15, it can be seen that the grain pre-preparation method has a narrow grain size distribution and an extremely low degree of twinning even for various silver halide grain compositions.

Next, each emulsion was chemically sensitized and optically sensitized by the same procedure as in Example 1, and then coated and dried to obtain a sample.
It was developed and the results are shown in Table 16.

Table 16 As shown in Table 16, it was found that the silver halide emulsion had low capri and high contrast.

<Example 3> Using the same particle preparation method as in Example 1m2, the first EAg time and second EAg time were changed as shown in Table 17, and sample N was prepared.
a17-19 were prepared. N1117 and N1118 are ≠ μ ratio samples according to the present invention, and N119.20 is the first
EAg time Table 17 The flow rates of BW and C liquids added during the preparation of each sample are the same as in Example 1 sample N112.

The obtained emulsion was chemically sensitized by the same procedure as in Example 1.
It was optically sensitized, coated and dried, and its photographic properties were evaluated.

' The grain and photographic characteristics of each sample were as shown in Tables 18 and 19.

Table 18 Table 19 The sample m17.18 according to the present invention has low capri and high gamma, while the control sample N119.20 has the first EAg.
When the tl value is long, the gamma decreases and the fog increases (Example 5) Using a solution with the same formulation as in Example 1 and changing the holding time of the second EAg value, the AgC1:AgBr ratio TO: 30 was obtained. Emulsions were prepared and samples N1121-25 were obtained. The total addition time and the time for the first EAg value were kept constant at 80' and 5', respectively, and only the hold time at the second EAr was varied. The addition flow rate was the same as in Table 2. After the 2nd EAg time in Table 20, the EAr control was stopped and the addition of solutions B and C was continued, but the EAg increased gradually and was out of the range of the present invention.

Samples N121 to N23 are samples of the present invention in which the second EAR time is greater than or equal to the total addition time.

Table 20 The particle state and photographic characteristics of each sample determined in the same manner as in Example 1 were as shown in Tables 21 and 22.

Table 21 Table 22 Samples 21 to 23 according to the present invention are the comparison sample N1124.
0 has higher monodispersity and higher gamma than 25 [
[Effects of the Invention] As is clear from the above examples, the method of the present invention is simple, and by controlling (Eλt), there is almost no occurrence of twins even in a relatively fine particle size region, resulting in extremely monodisperse properties. It is possible to obtain a silver decagenide photographic emulsion with a high concentration. The photographic properties of the resulting emulsion are high sensitivity relative to the grain size, low fog, and high contrast. , Agent Patent Attorney No 1) Father-in-law 371

Claims (1)

[Claims] A method for producing a silver halide photographic emulsion in which an aqueous solution of a water-soluble silver salt and an aqueous solution of a water-soluble halide are added to an aqueous solution of a hydrophilic colloid by a double jet method. The hydrophilic colloid aqueous solution is added to the hydrophilic colloid aqueous solution for a period of time such that the growth rate of silver halide grains in the hydrophilic colloid aqueous solution does not exceed the critical growth rate and corresponding to 1/30 to 1/5 of the total addition time from the start of mixing. The E_A_g value of the aqueous colloid solution is 140 mV.
to substantially maintain the E_A_g value at a constant value set within the range of 80 mV to 200 mV, and then substantially maintain the E_A_g value at a constant value set within the range of 80 mV to 140 mV for a time corresponding to at least 1/2 of the total addition time. A method for producing a silver halide photographic emulsion in which addition is carried out at an addition rate maintained at .