JPS60220337A - Preparation of silver halide photosensitive emulsion - Google Patents

Abstract

PURPOSE:To enable effective operation of desalting and rinsing steps of a silver halide photosensitive emulsion using an org. gelatin coagulant by carrying out the whole courses of the steps or parts of them at a prescribed temp. range. CONSTITUTION:When the desalting and rinsing steps of a silver halide emulsion is executed by the org. gelatin coagulation method, gelatin is coagulated with the org. gelatin coagulant, a supernatant soln. is removed, and the operations of rinsing are carried out at a temp. of >=28 deg.C. As a result, the coagulated grains are made properly coarse at the time of coagulation and decantation rinsing to elevate settling speed, and to reduce the bulk volume of settled coagula. The ordinary gelatin for use in silver halide emulsion is used, and as the org. coagulant, water-soluble polymer having sulfonic acid or carboxylic acid groups are used in an amt. of 3-50wt% of the solid weight of the gelatin in the sliver halide emulsion. The emulsion is coagulated, preferably, in a pH of <=5, and, good results are obtained in a gelatin concn. of 0.3-3.0wt% at that time.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for producing a silver halide emulsion, and more particularly to an improvement in the desalting and water washing process of a silver halide emulsion using an organic gelatin flocculant.

Generally, during the manufacturing process of photographic silver halide emulsions, after physical ripening, excess halide, by-produced nitrates, ammonia, etc. are removed, and the silver halide emulsion is further concentrated. Includes salt and water washing process.

There are various methods for this desalting and water washing process, but a chemical that coagulates gelatin is added to coagulate and precipitate the silver halide grains, and the supernatant liquid is discarded.
A coagulation-sedimentation method is widely used in which desalting is performed by washing with water two or three times. Coagulation precipitation methods include sulfate method, organic solvent method,
There are an organic gelatin flocculant method and a gelatin derivative method, but in recent years, the organic seratin flocculant method has been widely put into practice because of its ease of operation. The desalination method is described in detail in the Basics of Shachogegaku (edited by the Japan Shasei Gakkai, published by Corona Publishing).

The organoceratin flocculant method involves adding a water-bathable polymer compound having a sulfonic acid group or a carboxylic acid group or a relatively large molecular weight field [tfl activator] to a gelatin-silver halide emulsion to lower the pH (usually (PII 5 or less) is coagulated and sedimented, the supernatant liquid is discarded, and the resultant is washed with water using Decanchi/Con to desalt.

In this method, the important points are the roughness of the gelatin aggregate particles (hereinafter referred to as aggregates) that coagulate containing silver halogenide particles and the bulk of the aggregates when they settle. becomes. If the aggregates are too fine, the sedimentation rate of the aggregates during coagulation or washing with decanting/feeding will be slow and the settling time will be prolonged. If the aggregates are of the same size and are crushed, the sedimentation rate will be high, but the washing efficiency in water washing with Tekankeyon will be poor.

The volume of the flocculates during sedimentation is also important; if the volume is high, the amount of clear liquid to be discarded during coagulation or washing with water will be reduced, resulting in lower washing efficiency and concentration ratio of the silver halide emulsion. Therefore, in the desalting and water washing step, it is required that the flocculates be properly assembled, have a high sedimentation rate, and have as low a volume as possible during sedimentation.

In order to meet these requirements, coagulation is usually carried out by appropriately selecting conditions such as ceratin concentration, pH, amount of organic flocculant, and stirring speed during coagulation, but the effect is unstable and requires theoretical analysis. Coagulation conditions were determined empirically or by trial and error. In addition, the temperature during the desalting and water washing process is an important condition, but in the sulfate method and organic solvent method, water washing is usually carried out at a temperature of 20°C or lower to avoid dissolving emulsion aggregates during the water washing process. Since the concentration of salts or solvents is extremely low during the washing process, if washing is carried out at a temperature higher than the temperature at which the gelatin is dissolved, aggregates will form and washing with water will not be necessary. It becomes possible.

In the organoceratin flocculation method, the emulsion is flocculated by combining ceratin and organic gelatin flocculants at a temperature below I5, so even if washed with water at a temperature higher than the yarn temperature of the ceratin, the aggregates will not dissolve. doesn't happen. However, in the conventional method, due to concerns about emulsion aggregates, it has been common practice to carry out washing with water at a temperature below the melting temperature of the gelatin, similar to the sulfate method and the organic solvent method.

The purpose of the present invention is to desalt and wash silver halide emulsions with R-4J.
The object of the present invention is to provide a method for effectively performing the following steps.

The present inventor has investigated various conditions under which the sedimentation time of the aggregates in the culm is shortened and the volume of the sedimented aggregates is reduced, that is, the concentration ratio of the emulsion is increased. The temperature at the time of coagulation in the water washing process and the water washing with Teka/Te=/Yon is a very important factor.At low temperatures, the aggregates are finer and the sedimentation rate is slow, and the bulk of the aggregates when they settle is high. We found that the opposite effect occurs at high temperatures, and that the effective limit temperature is 28°C. In other words, when desalting and washing the Paroge/Silver Fide emulsion using the organic gelatin flocculant method, the procedure of flocculating the gelatin with the organic gelatin flocculant, discarding the supernatant liquid, and washing with water using Tecante/Yon is required.
By performing the operation at temperatures above ℃, the temperature during coagulation and the
It was possible to appropriately coarsen the aggregate particles during washing with water, increase the sedimentation rate, and reduce the volume of the sedimented aggregates, thereby achieving the object of the present invention.

The first effect of the present invention is that the time required for desalting and washing can be shortened, and the second effect is that the concentration ratio of Rogge/silver oxide emulsion can be increased.

If the temperature of the present invention is 28°C or higher during agglomeration and water washing with Tekante/Yon, the sedimentation rate can be increased and the volume of aggregates and settled aggregates can be reduced, but the higher the temperature, the higher the The more powerful the effect is. However, if the temperature exceeds 45°C, the flocs will take on a glaze-like appearance, which is undesirable, and it is preferable to select the degree of settling width in the range of 28°C to 40°C, depending on the desired settling time and concentration ratio. Furthermore, even if the temperature during coagulation is 28°C or lower (for example, 20°C) (at this time, the aggregates are fine and the thickness is high), the aggregates can be removed by setting the temperature during water washing to 28°C or higher. Accordingly, the bulk can be reduced.

The temperature effect of the present invention is due to its effective limit temperature (28°C
) is almost the same as the melting point of gelatin celery, so it is believed that the seratin around the aggregate particles slightly dissolves during coagulation and washing with water, and the aggregates become fused together and become rough. The person is thinking that the gelatin used in the invention is Nishijo Haloken f silver emulsion ((the used seratin (e.g. removes the alkali) tin, acidic method seratin/, removes 11.1, low cal /Uno, Seratin, etc.), and in short, it is not particularly limited as long as it is organic gelatin or gelatin that is coagulated by grinding.

The organoceratin agglomerate used in the present invention is a water-based polymer compound having a sulfonic acid group or a carboxylic acid group, or a surfactant with a relatively large molecular weight.
8-140322. In particular, the following polymers can be cited as typical examples.

A1 Noni 2 a:b=l:9~9:1 (molar ratio) SO5N a S (J5 N a m is the degree of polymerization and a - d These organic gelatin flocculants have a molecular weight in the range of 1,000 to 100,000 in terms of composition ratio.

Commercially available products include Versa TL (Kanebo NSNO Co., Ltd.) 5clipset (Monsanto Company, USA) and EMA (Monsanto Company, USA).

The organic gelatin flocculant used in the present invention may be used in combination with another flocculant, such as a sulfate (macneum sulfate, sodium sulfate, etc.), and the effects of the present invention will not be impaired even if the combination is used.

The organoceratin flocculant used in the present invention is used in an amount of 3 to 50 weight percent based on the solid weight of seratin in the halide silver halide emulsion, and preferably 3 to 20 weight percent in consideration of resolubility. Also, the gate to coagulate (is 5 or less, preferably 3
~4.5 is good.

The silver halide emulsions to which the present invention is applied are mainly gelatin-based silver halide emulsions such as black and white emulsions, fogged direct positive emulsions, color emulsions, silver chloride emulsions, silver bromide emulsions,
Silver chlorobromide emulsion, Silver iodobromide emulsion, // Gourget emulsion,
With double jet emulsions, etc., it is not limited by the type of emulsion or the size of the silver halide grains. Furthermore, there are no particular limitations on the ratio of silver to gelatin in the silver halide emulsion or the excess of halogen, and the effects of the present invention are not impaired by the ratio of button to gelatin and the excess of halogen.

The gelatin concentration of the silver oxide emulsion used in the present invention at the time of coagulation is 0.3~; Seratin flocculant, P
The effects of the present invention can be obtained by appropriately adjusting t1 and the like.

The silver oxide emulsion to which the present invention is applied is a silver oxide emulsion mainly composed of ceratin, but other water-soluble polymer compounds (for example, human butterflies/methylcellulose, carboquine methylcellulose, acrylic Acid polyacrylamide, polyvinyl alcohol, etc.) can be used in combination with Serachi/ to the extent that it does not interfere with carbonization using an organoceratin flocculant.

Example 1 Seratin concentration in the silver halide emulsion was 1i% double, the ratio of silver (in terms of silver nitrate) and gelatin was 5:1, pAg 6
．． 5 silver chloride double jet emulsion 809 with a scale of 10
0 m1! Take a beaker, and add the gelatin flocculant described in the specification (5 parts by weight aqueous solution) to the solid amount of seratin while stirring so that the amount becomes 10 parts by weight.
is adjusted to 3.0 to 3.4 with IN sulfuric acid, and a silver halide emulsion is coagulated according to the conditions shown in Table 1. Furthermore, after the flocs have completely settled to the bottom of the bottle (the supernatant liquid becomes transparent) and have come to rest, the surface of the flocculates that has settled to the bottom of the bottle is discarded by sieving and discarded with 80 mI of pure water. Add, stir for 3 minutes, and wash with water. After the floating aggregates have settled down completely to the bottom of the bottle, discard the liquid. Repeat this washing with water twice. The results of measuring the sedimentation time of the aggregates during coagulation and washing with water at each temperature, and the volume and shape of the sedimented aggregates are summarized in Table IK-1°.

As shown in Table 1, 28℃ compared to 20℃ and 26℃,
At 35°C, the sedimentation rate of aggregates is faster and the size of the cavities is lower.

Example 2 Silver bromide double jet emulsion 702 with gelatin concentration in silver halide emulsion of 1.7 weight ratio, silver to gelatin ratio of 9=1, and pAg of 7.6 was prepared using a 100-Bee force with a scale. To the solid amount, add the gelatin flocculant described in the specification (5 liters in a water bath) with stirring to a weight of 20 kg, and add 3.0 to 3.0 kg with PH'KIN sulfuric acid.
4, then a magnesium tte acid water bath solution (
MgSO4・7H2050 weighted %) 1 based on the total amount of emulsion
Gradually add 5% by weight and coagulate the silver halide emulsion according to Table 20.

Hereinafter, the aggregates were sedimented in the same manner as in Example 1, and the upper U7
Discard fl and wash twice with 70rnl of pure water.

The settling time of the aggregates during coagulation and washing with water at each temperature, the volume and shape of the settled aggregates are shown in Table 2.

Cloth・2 *1 Temperature during washing: 37℃ As shown in Table 2, there is a clear difference in sedimentation rate and bulk when the temperature during coagulation and washing is 20℃ and 28℃ or higher. However, washing with water increases the bulk, but 28
At temperatures below 1°C, the bulk becomes lower.

Also, even if coagulation is performed at 20°C, will it still be possible to wash with water? Increase crystallinity 37
℃), the sedimentation rate increases and M,・1 also decreases.

Claims (1)

[Claims] (1) Silver halide photography characterized in that in the desalting and water washing process of a halogen silver photographic emulsion using an organic gelatin flocculant, all or part of the process is carried out at a temperature of 28°C or higher. Methods for producing light-sensitive emulsions.