DE2609742C2 - Process for the introduction of photographic additives in silver salt emulsions - Google Patents

Description

The invention relates to a process for introducing photographic additives which are substantially insoluble in water into silver salt emulsions, the additives having a particle size of have less than 1 μπι and are capable of the sensitometric properties of the silver salt emulsion To influence silver salt.

It is known that photographic additives have an absorption capacity on grain surfaces of silver salts

have, such as sensitizing dyes or stabilizers, in a suitable solvent, such as. B. To add methyl alcohol or dimethylformamide, dissolved, to photographic silver halide emulsions. (See. P. Glafkides, Photographic Chemistry, London 1958, Vol. II, pages 902 and 904).

However, these known methods are practically insoluble in water and conventional for incorporation Solvents poorly soluble stabilizers or spectral sensitizing dyes are not suitable because

known to be too large amounts of solvent, disadvantages in terms of diffusion or migration of the Bring sensitizing dyes within the emulsions (cf. Column 1 in DE-PS 19 64 169).

As is known, it is possible to use other emulsion additives such as color couplers which are not added after incorporation into the photographic emulsion to be retained on the surface of the silver halide crystal by absorption, to be incorporated in the silver halide emulsion in the form of dispersions. This is generally done

for example, the coupler compound is dissolved in a suitable solvent which is generally immiscible with water, optionally in the presence of an oil former and suitable wetting agent, and emulsified in an aqueous gelatin solution. The low-boiling solvent is then generally used from this emulsion removed and the dispersion thus obtained is admixed with the photographic silver halide emulsion.

The use of such a method for spectral sensitization is described in DE-PS 15 47 705

described. From DE-PS 19 64 169 a process is also known in which the preparation of a dispersion is obtained from spectral sensitizing dyes in an aqueous gelatin solution through the following processing steps:

1. Milling together the sensitizing dye with a water-miscible organic dye w> liquid and

2. Adding the ground stock thus obtained to an aqueous gelatin solution. The organic liquid has in this process has the task of separating the dye molecules during the grinding process achieve and prevent agglomeration of the dye particles.

The disadvantage of the known process, however, is that the dispersion obtained in this way is subsequently made only in the case of using low-boiling organic solvents, the solvent in Can be removed to a certain extent, but this is too considerable in the case of polar solvents Problems. Polar solvents, especially protic solvents, can only be obtained from aqueous Gclatinedispersioncn

can be removed by heating, which significantly affects the stability of the sensitizing dye molecule In addition, removal of the solvent from the dispersion in vacuo can be significant Cause foaming.

Even if non-polar solvents are used, all known measures are in practice unsatisfactory for removing low-boiling solvents from aqueous dispersions. If no elevated temperatures are used to evaporate the solvent, the solvent can only removed in insufficient quantity. The aforementioned speaks against the application of a vacuum Foaming, which occurs to an even greater extent Against the use of increased evaporation temperatures speaks, which previously mentioned, on the other hand, the easy decomposition of the sensitizing dyes.

A remaining amount of solvent in the dispersion is also disadvantageous for several reasons. First of all, even the smallest residual amounts promote residual crystallization processes in the photographic layer, which do not only affect the specially introduced additives, but also other additives, such as coupler compounds, adversely affect. In addition, the presence of residual amounts of polar, water-miscible effects organic solvents in silver halide emulsions, especially in silver-rich emulsions with a high silver packing density that the stability of the casting emulsion is considerably reduced, which is Noticeable through reduced digestion stability The following disturbances can occur: Phase separation between hydrophilic and hydrophobic phase, agglomeration and coalescence as well as flocculation phenomena before casting.

There has therefore long been a need for a method with the help of which it is possible, also in Water practically insoluble photographic additives, such as sensitizing dyes or S'.r-bilizers, in Incorporate super salt emulsions without the emulsion layer being miscible with water or not pollute miscible organic solvents; is, and without that for the production of emulsion layers The dispersions required experience disadvantageous changes even after long periods of use.

The object of the invention is to provide such a method which is also practical in water with the help of it insoluble photographic additives such as stabilizers and sensitizing dyes in silver salt emulsions incorporated and thus effectively stabilized with water-insoluble stabilizers or with in Water-insoluble sensitizing dyes can be sensitized.

This object is achieved in that the substantially water-insoluble photographic additive in an aqueous phase in the presence of a monomeric, oligomeric or polymeric alkylarylsulfonate at least 16 carbon atoms, which, when 1 g per liter is used, has a surface tension of at least 0.038 N / m in water is caused by grinding and that, if necessary immediately after storage or processing, the dispersion obtained is admixed with a silver salt emulsion.

In contrast to known processes, the process according to the invention is carried out by grinding the photographic Additive, without any use of a water-miscible organic solvent, so that by introducing the photographic additives into emulsions by the process according to the invention no time-consuming and laborious removal of solvent quantities from the dispersions produced is necessary and, in addition, no layer load from undesired residual amounts of organic Liquids is caused.

In addition, the method according to the invention does not require any precautionary measures for solvent absorption from the circulating air when pouring and drying the silver salt emulsion, so that the invention Process does not give rise to any environmental problems.

The milling of the photographic additive is carried out in one step according to the process according to the invention aqueous phase, d. H. in a phase which consists essentially of water, such as e.g. B. distilled water or also tap water. The aqueous phase can also contain small amounts of customary additives, such as they occur, for example, in tap water. These additives include small amounts of calcium salts in Amounts not exceeding 0.5% or traces of heavy metal. The aqueous phase can also, if desired, hydrophilic binders, such as. B. gelatin, or inorganic or organic salts, such as. B. sodium chloride or anti-limescale agents.

According to the invention, however, the aqueous phase does not contain any water-miscible organic solvents, which might be able to partially dissolve the photographic additives. -, 0

Methods for incorporating coupler compounds into photographic emulsions are known in the art known, according to which couplers grind in the presence of wetting agents and suitable coupler solvents will.

It was surprising to find that the use of conventional wetting agents instead of those according to the invention Alkylarylsulfonate gave practically unusable results, since the milling process turned out to be extraordinary problematic designed. Foaming could practically not be avoided, and so did the grist migrated from the grinding media by flotation so that further comminution to the desired level The degree of comminution was not possible.

The amount of alkylarylsulfonate required by the process according to the invention, based on the to dispersing photographic additive, can vary within wide limits and is based on the feo essentially according to the nature of the special photographic additive. In general, an addition of 0, 1-3 parts by weight of alkyl aryl sulfonate per part by weight of photographic additive has been found to be sufficient. It however, it is also possible to add more than 3 parts of alkylarylsulfonate.

The aqueous dispersions prepared according to the invention are characterized in ^c all the use of z. B. spectral sensitizers and stabilizers have excellent storage stability, especially if b5 to the aqueous phase after grinding and separating d: r grinding media an aqueous solution of a water-soluble polymer, such as. B. an aqueous gelatin solution is added. The aqueous gelatin dispersion prepared in this way can be stored for months at room temperatures without the decomposition

dispersed dye or stabilizer molecules and thus a decrease in the spectral sensitization or stabilizing effect is observed after addition to the emulsion.

However, it is also possible to pour the aqueous peptide-containing dispersion onto a support for storage purposes and to dry it. After the desired storage time, the dried dispersion can then be used redissolved and added to the photographic emulsion.

According to a particular embodiment of the process according to the invention, the aqueous dispersion is

worked up in a particularly gentle way before incorporation into the photographic emulsion and thus

transferred into a storable and very durable form, from which they can easily and easily to any desired

Point in time without complicated dissolution processes and / or application of heat of the photographic emulsion

jion can be added.

According to the particular embodiment, the aqueous dispersion is processed by a Drying in one of the devices, as used in the processing of formed pigments or dyes in the Technique are known, such as. B. Schaufeltrockncr, atomizer disks, or preferably by devices that are for the Spray drying or freeze drying are suitable.

The water used for dispersing is reduced to a very high level by freeze-drying or spray-drying gently removed without agglomeration of the dispersed particles.

For spray drying, devices with a single-fluid nozzle, which are known to produce granules, can be used or with a two-fluid nozzle that produces a powder. More detailed information on spray drying can be found in the Ulimann handbook, Enzyklopadie der Technischen Chemie, 4th edition, Vol. 2, Pages 255 ff.

The formed photographic additive produced in this way has a practically unlimited shelf life and is extremely stable and can be stored in the smallest of spaces, which was previously not possible with the known methods. The formed photographic additive can then be added at any time desired its preparation of the liquid photographic emulsion are mixed.

It is of course also possible to first mix it with water or an aqueous binder solution and then mix the aqueous dispersion obtained in this way with the liquid photographic emulsion.

The type of addition is arbitrary and depends essentially on the type of photographic emulsion used and the desired effect. If a low-gelatin, but high-silver-salt emulsion is to be produced, the direct incorporation of the formed photographic additive or incorporation is appropriate in the form of a highly concentrated aqueous dispersion.

Examples of monomeric alkyl aryl sulfonates are the alkali salts of diisopropylnaphthalene sulfonic acids or di-sec-butylnaphthalenesulfonic acids.

Examples of oligomeric and polymeric alkyl aryl sulfonates are condensation products of naphthalene or ditolyethers with formaldehyde and sulfuric acid or lignin sulfonic acids.

The milling of the photographic additives to particle sizes of less than 1 micron takes place with known suitable mills, the shear forces must be sufficient to the grinding stock to the required To be able to comminute particle size in a useful period of time. Such suitable mills are in Commercially available under the collective term colloid mills.

The so-called sand mill types are particularly suitable as colloid mills for the process according to the invention. Examples of commercially available mill types of this type are:

I. Sand-Mili from P. Vollrath, machine works Cologne,

2. Perl-Mill from Draiswerke GmbH, Mannheim

3. Dyno-Mill from W. A. Bachofen. Machine works, Basel

4. Masap mills from Masap AG, Matzendorf, Switzerland

Methods and suitable mills are also described in US Pat. Nos. 2,581,414 and 2,855,156. An example of a laboratory-scale sand mill is shown in FIG. 1 shown.

The material of the container B for the grinding process is expediently made of glass or steel. A particularly suitable steel container for the method according to the invention is one that has been manufactured from hardened steels, since otherwise the abrasion can become too great. Such abrasion would lead to considerable contamination of the dispersion and thus the photographic emulsion and would adversely affect the photographic properties of the latter.

The grinding container B is surrounded by a cooling jacket made of PVC or metal K and is expediently cooled by a cooling liquid F during the grinding process. As a cooling liquid is flowing water generally sufficient to completely remove virtually the generated heat during the grinding and not to let the temperature of the ground material to rise above 40 ⁰ C. The dimensions of the container are: 4 mm wall thickness: clear width of the interior 75 mm; Height 230 mm. A stirrer shaft R with a diameter of 15 mm and four 5 mm thick Duramid or Durethan disks with a diameter of 60 mm protrudes into the stirred tank. The four disks are each arranged separated from one another by a distance of 20 mm.

The agitator shaft is moved by a drive motor M with a speed of up to 10 ⁴ revolutions / minute b5. The drive motor can be arranged centrally or laterally next to the drive shaft and drive the drive shaft via a V-belt.

The fill level is about 1⁄2 a high, and 5 to 80 g of grist are ground in the mill per operation, for which at least three to four times the amount of grinding media are added to the grinding stock for grinding.

The mean particle diameter of the grinding media used depends on the particle diameter of the material to be ground before grinding. Optimal results are achieved when the mean particle diameter of the ground material is at most ² / j of the particle diameter of the grinding media. If the grist has a larger particle diameter, it is advisable to reduce it beforehand using a conventional process.

The amount of water required for grinding can be varied between 20 ml and 200 ml, depending on the type of s Millbase and alkylarylsulfonate used, it being possible to vary the amount of dispersing medium used within wide limits, as already stated above.

If .: in general, the milling process is carried out as follows: 40 g of ground material are mixed with 200 g of glass beads. z. B. reflective pearls from Dragonwerk Georg Wild, Bayreuth, with a diameter of 0.85 mm to 0.95 mm depending on the particle size of the ground material, mixed and mixed with 100 ml of water and 15 ml of a 40% alkylarylsulfonate in the form shown in FIG. I grind the laboratory sand mill described (for 3 hours at a stirring speed of 7000 rev / minute). The temperature inside the mill is ^{kept below 40 °} C. by adjusting the cooling water supply. The entire contents of the mill are then filtered through a glass frit (pore size: 40-90 μm) into a glass filter pot.

According to a particular embodiment, 2.51 of a 10% gelatin ^{solution heated to 40 ° C. is located in the glass filter pot.} A further 2.5 liters of a 10% gelatin solution are then added to this filtrate and the dispersion obtained in this way is made up to 101 with water.

The filtrate obtained in this way is briefly heated again to 40 ° and stored at 4 ° C. to solidify. That gel-like Solidified dispersion can now be added to the photographic silver halide emulsion directly or after further storage.

In addition to the glass beads described above, quartz sand or are also advantageously suitable for grinding Silicon carbide sand.

According to the preferred embodiment, the filtrate obtained above is subjected directly to either freeze-drying or spray-drying, as described in detail below.

The photographic additive used in the process of the invention is in the aqueous phase in The presence of the alkylarylsulfonate dispersed without being dissolved. In the method of the invention any photographic spectral sensitizing dye can be used. The dyes which are practically insoluble in aqueous solutions are particularly suitable, e.g. B. Dyes in water 20 ° C have a solubility of less than 0.1%. Dyes used to carry out the process of Invention are suitable, are already known from numerous patents, for example, refer to those in the jo DE-PS 19 64 169 described pointed out.

In the following Table A a number of spectral sensitizing dyes are listed which are used in the Examples described below were used.

IO 15th 20th 23 JO 35 40 45 50 55 60

Table A. Dye no. formula

IV

VI

vn

vm

C ₂ H ₅ C

N N

_n ^ = CH-CH - CH- ^

nc ι ι

(CHJ) ₄ SOjNHCOCH ₃ C ₂ H ₅

C ₂ H ₅

I C

Bi ⁶

CN

(CHj) ₄ SO ₃ Na (CHj) ₄ SOf

C ₄ H ₅

CH ₃

Se

IC ₂ H ₅

I,

(CHj) ₃ SOf

C ₂ H

₂ H ₅

I (CHj) ₅ SOf

IC ₂ H ₅

CH ₃

C ₂ H ₅

CH ₃ I.

C ₂ H ₅

I CH ₃

CH ₂ <

₂ CH ₂ COOH

C ₂ H ₅

C ₂ H ₅

CHj) ₃ SOf

C ₂ H ₅

> = CH-C = C-S

c ₂ e ₅

C ₁ H,

C ₂ H ₅

continuation

Dye no. formula

IX

NC ₂ H ₅

C ₂ H

₂ n ₅

C ₂ H

(CHj) ₃ SOj ⁹

The dye dispersions used in the process of the invention may also contain binders, e.g. B. Contain gelatin, the ratio of colorant to gelatin varying within a wide range can be. However, the best results in spectral sensitization are obtained with such dispersions obtained in which the dye content is between 5 and 20% based on the total weight of dye + Binder, lies. Those used in the method of the invention for spectral sensitization of photographic Dye dispersions used in silver halide emulsions can also contain two or more dyes in each dispersion or it can also contain dispersions that contain only a single dye in Combination with two or more such dispersions can be used. To achieve an optimal Sensitization according to the method of the invention can determine the optimal concentration of the in the emulsions incorporated dye depending on the dye used and the emulsion used in general between 0.2 and 4 g of dye per mole of silver halide of the emulsion can be varied, fine-grained As a rule, emulsions have a higher need for sensitizing dyes than coarse-grained ones.

Any photographic stabilizer can be used in the method of the invention, from which, in turn, are particularly suitable for those that are practically insoluble in aqueous solutions, e.g. B. stabilizers, which have a solubility of less than 0.1% in water at 20 ° C.

Examples of such stabilizers are known and described in numerous publications, e.g. Am U.S. Patent 3,692,527.

The stabilizers used in the examples described below are listed in Table B below vsrwsnds! became

Table B.

Stabilizer no.

formula

40 45

55

The stabilizer dispersions used in the process of the invention can also contain polymeric binders such as B. contain gelatin, the ratio of stabilizer to gelatin within a wide range Range can be varied; In general, dispersions with a stabilizer have also been found Stabilizer content of 5 to 20%, based on the total weight of stabilizer and binder, has been tried and tested. To achieve adequate stabilization according to the method of the invention, the concentration can of the stabilizer incorporated into the silver salt emulsions depending on the type of stabilizer and the one used Emulsion can be varied between 20 mg to 2 g of stabilizer per mole of silver salt.

The photosensitive silver halide can be used in any hydrophilic colloidal binder used for Dispersion of silver halides is suitable to be dispersed, e.g. B. in gelatine, albumin, alginic acid, polyvinyl alcohol, Polyvinyl pyrrolidone, cellulose ethers or partially hydrolyzed cellulose acetate. The hydrophilic However, colloid can also be dispersed vinyl polymers and water-insoluble polymers from Alkvlacrv-

60

Iates and methacrylates, acrylic acid, sulfoalkylacryates or methacrylates contain.

Light-sensitive silver halide emulsions are suitable as photographic silver salt emulsions, or Silver salt emulsions, the silver salt of which is wholly or partially composed of light-insensitive silver salts of long-chain aliphatic carboxylic acids with in particular from 0 to 30 carbon atoms, e.g. B. Silver salts of the earthquake acid, Palmitic or su aric acid. Such silver salt emulsions can also contain silver halides, the light-insensitive silver salt emulsion is admixed as such or in situ on the grain surface of the light-insensitive silver salts have been produced by adding halides. About these emulsions include the so-called thermophotographic against light. Silver salt emulsions sensitive to UV or IR radiation.

ίο As silver halide emulsions are the usual silver chloride. Silver bromide, silver chlorobromide or Silver chlorobromide iodide emulsions are suitable

The method according to the invention is particularly suitable for stabilization or spectral sensitization of silver salt-rich photographic emulsions. Silver salt-rich photographic emulsions are generally understood to mean those emulsions

They have a gelatin to silver weight ratio, expressed as silver nitrate, of less than 1. Such Emulsions have heretofore been known for use as emulsions for photographic recording materials With increasing efforts to improve the sensitivity and sharpness of photographic recording materials. becomes the silver halide packing density in modern photographic emulsions increased by reducing the proportion of binder. These emulsions often have a gelatin-silver Ratio of 0.2 to 0.7 in extreme cases only 0.1. These emulsions are used in the context of color photography Materials emulsified color couplers mixed in. With these emulsions or casting melts, the dispersion stability is of crucial importance, and it can contain undesirable amounts of residual solvents as well larger amounts of wetting agents, which reduce the surface tension too much, lead to a even casting and thus the production of high quality materials is not possible The for the drying process, such as. B. spray drying or freeze drying, according to the preferred embodiment of the method according to the invention to be used equipment and process measures are known in the art and need not be described in detail here. Referred s-: i z. B. on the manual by Ulimann, Enzyklopadie der Technischen Chemie, 4th Edition, pages 712 ff. And Pages 716 ff. And the series "Fundamentals of Chemical Technology" with the title "Drying" by Dr. Ing.

Friedrich Kneule, 3rd edition, 1975, in which methods of freeze drying on pages 472 ff. And atomization drying on pages 401 ff. Are described.

In the case of spray drying processes, drying in an inert gas atmosphere can, if desired be made. In the case of freeze-drying, shock freezing is particularly beneficial, ζ. B. with liquid nitrogen, and subsequent usual sublimation at higher temperatures, however must be below the melting point of the dispersion.

The method according to the invention is of particular advantage for the introduction of photographic Additives which have water-solubilizing groups, such as sulfo groups, but their water solubility not sufficient to incorporate them as aqueous solutions into photographic emulsions. Will such Photographic additives according to the method described in DE-PS 15 47 705 or 19 64 169 initially in

«Ο dispersed in an aqueous gelatin solution it can happen that the photographic additives as a result of the van der Waals' interaction are so firmly absorbed on the gelatin that after the introduction of the aqueous gelatin dispersion in the photographic silver salt emulsion the ability of the photographic

The addition of influencing the sensitometric properties of the silver salt diminishes Are such additives according to the inventive method by one of the drying

Formed using methods, they can be stored indefinitely without their ability to hold silver salts in affecting photographic emulsions is adversely affected. In the following, the invention is further explained using a few examples:

example 1

3 g of the sensitizer VIII were mixed with 7 g of the sodium salt of di (sulfonaphthyl) methane with the addition slurried with a little water (approx. 50 ml) and then mixed with 200 g of quartz sand with an average grain diameter of approx. B. in FIG. 1 stated, ground for 2 hours.

The sensitizer compound used initially had an average grain size before milling of

about 0.6 mm. After grinding, the mean particle size was reduced to 03 μm (if the to grinding sensitizer has a grain size greater than 0.6 mm before grinding, it must are first pre-ground to a grain size of less than or equal to 0.6 mm using a conventional mill, before it is ground in the sand mill as previously described). The proportions of the grain of the

The material to be ground and the diameter of the grinding media must be optimized, whereby the rule of thumb can be that

The best results are achieved when the mean grain diameter of the grist is no more than ³ Λ of the mean grain diameter of the grinding media.

The aqueous dispersion thus obtained was after separation from the grinding media with liquid nitrogen shock frozen and stored in a dry state after sublimation A sample containing 260 mg of the sensitizer was added directly and further samples were added in succession at intervals of 4 weeks to 1000 g each of a silver halide emulsion of the following composition

To 1000 g of this silver bromide iodide emulsion having a silver halide content of 0.55 mol per kg was added also 100 ml of a 1% aqueous solution of 4-hydroxy-6-methyl-1,2Ya-7-tetraazaindene 20 ml of a 1% aqueous pyrocatechol solution and 50 ml of a 5% sodium salt solution of pentadecylene amber

acid diglycolide added. 42 g of blue-green color couplers of the formula were used as color couplers OH

-CONH (CHj) ₄ O- <f> - LC ₄ H,

together with 21 g of dibutyl phthalate and 4.2 g of sodium dodecylbenzenesulfonate in emulsified form in 400 ml of a 2% strength gelatin solution were added to the silver halide emulsion.

The emulsion obtained in this way was then poured onto a transparent substrate Cellulose triacetate evaluated sensitometrically in the usual way

This evaluation showed that in terms of sensitivity, gradation and maximum density the only ones Samples, measured over a period of six months, gave completely identical results.

The sensitizing effect of the sensitizer was not impaired by storage in a dried state impaired

In comparison with this, a photographic material which had been prepared as described above was evaluated sensitometrically, with the exception that, after grinding in the sand mill, the sensitizer dispersion was admixed directly with the silver halide emulsion.

The evaluation of the sensitometric results shows that in terms of sensitivity, gradation and Maximum density of the photographic emulsion that was sensitized with the freshly prepared sensitizer dispersion yielded completely identical routes with those that were sensitized with the freeze-dried sensitizer have been sensitized.

The comparison shows that the effect of the spectral sensitizer by the freeze-drying treatment has not been affected in any way

Example 2

80 g of sensitizer or stabilizer were mixed with 250 g of glass beads, available under the name Reflexperlen (Dragonwerke, Bayreuth) with a diameter of 0.85 to 0.95 mm, and together with 100 ml of water and 3 ml of a 40% aqueous solution Grind solution of a polymeric alkylnaphthalene sulfonate for 3 hours J5 at a speed of rotation of 7000 revolutions per minute in the laboratory sand mill shown in FIG. The temperature inside the mill was ^{kept below 40 °} C. by adjusting the cooling water supply. Then, the entire mill contents were μητι through a glass frit having a pore size of 40 to 90 filtered in a glass filter pot, in which is a 51 to 40 ⁰ C heated 10% gelatin solution were. After the filtrate was washed out well, a further 5% of a 10% liquid gelatin solution was added to the filtrate. It is then made up to 201 with water.

The filtrate thus obtained was again heated briefly to 40 ⁰ C and stored at 4 ° C to solidify the gel-like solidified Dispersion was added for sensitization or stabilization purposes directly, or the silver halide emulsion could be stored for any length of time before the addition.

The dispersions produced in this way each contained one of the aforementioned sensitizers I to X or each one of the aforementioned stabilizers Xl to XiI. Then they became silver halide emulsions such as described below added

1 kg of a silver bromide iodide emulsion containing one mole of silver halide per kg was mixed with one of the above Sensibilizer dispersions described, containing 260 mg of sensitizer No. IV and spectrally sensitized then a color coupler emulgal, the 30 g of the color coupler described in Example 1, 12 g of the dye so kuppler's formula

55 gust

21 g of dibutyl phthalate, 4.2 g of sodium dodecylbenzenesulfonate in 300 ml of an aqueous gelatin solution containing 10 g of gelatin were added. Subsequently, the begießfertige batch A, in a temperature-controlled at 40 ⁰ C circulatory system, which was operated with a centrifugal pump of the type Centrichem the ECO-pump Corporation transferred.

For comparison, an analogous color coupler emulsion B was prepared with the difference that the sensitizer instead of the method according to the invention in the form of a 0.05% solution in dimethylformamide

NHCOCHjO- f V-Cl

Silver halide emulsion was added.

Small aliquots were removed from the samples at intervals of 4 hours microscopically examined.

A further small portion was applied to a transparent base made of cellulose triacetate and after hardening with a water-soluble carbodiimide and conventional photographic processing (color development with the color developer N-EthyI-N - / oxyethyl-3-methyl-p-phenylenediamine at 38 ° C and one 3Ά minute processing time) with regard to gradation and surface gloss.

In the microscopic and surface gloss examination, the color coupler-containing photographic emulsion is examined for its stability of the color coupler with respect to crystallization phenomena Cloudiness or matting of the surface of the photographic material produced.

The following values were obtained:

The experiment showed that the presence of dimethylformamide in the casting solution reduced its dispersion stability quite considerably, so that crystallization began to appear after a stirring time of 8 hours could be observed. A comparison of the photographic materials showed that the use of the 8 hours digested Vergleichsgießlösung for photographic materials is problematic as the photographist "n properties expressed by the gradation values y \ and yi as well as the surface gloss of the photographic material were significantly affected. The comparison also shows that the photographic casting solution prepared according to the invention has excellent dispersion stability and leads to excellent photographic materials whose properties are in no way due to a longer service life

Casting solution has been affected. Example 3

A) To 1 kg of a silver bromide iodide emulsion containing 1 mol of silver halide per kg, v / urdetiit one according to Example 2 described prepared sensitizer dispersion, containing 130 mg of sensitizer I, spectrally

and then 150 ml of a 1% aqueous solution of 4-hydroxy-6-methyl-1,2,3a, 7-tetraazaindene, 2 ml of a 50% aqueous glycerol solution and 35 g of the purple coupler of the formula

sample Digestion time gradation 1.04 surface Crystallization (Hours) ; -ΐ 1.05 A. 0 0.68 1.07 glittering no B. 0 0.65 058 glittering no C. 8th 0.65 1.10 glittering no D. δ 0.58 0.75 ! light matting individual crystal platelets E. 24 0.70 glittering no F. 24 0.48 very strong matting predominantly octagonal as a result of crystallization Crystal flakes

NHCOCHjO -NHCO *

with 35 g of tricresyl phosphate and 3.5 g of sodium docecylbenzenesulfonate in 250 ml of a 3.5% strength aqueous solution Gelatin solution emulsified, added. Then 60 ml of a 4% solution of a wetting agent was added the formula

C ₄ H ₉ CH (CH ₂ H ₅ ) CH ₂ OOCCH ₂ CH (SO ₃ Na) COONHSO ₂ Ci ₅ HiI,

5 ml of a 1 η sodium hydroxide solution, 5 mm of a 5% KCr (CH jCOOV solution and 30 ml of a 1% catechol solution added.

B) The procedure was as described for sample A), with the exception that an additional one according to Example 2 The sensitizer dispersion prepared as described and containing 130 mg of the sensitizer II was added became.

C) The procedure was as described for sample B), with the exception that an additional one according to Example 2 prepared stabilizer dispersion, containing 65 mg of the stabilizer compound Xl, was added.

For comparison, comparative batches D) to F) were made using the method described for samples A) to C)

■ X produced, with the difference that instead of the sensitizer or stabilizer dispersion to the Sflberbro-

f midiodide emulsion the sensitizer I in the form of a 0.1% strength, the sensitizer II in a 0.05% strength and the

P stabilizer in a 0.05% methanolic solution was added. In Fig. 2 are the obtained viscosi-

ϊ? η of the individual casting solutions of samples D) to F) as a function of the converted methanol s

% amount applied. It can be seen that even a small amount of methanol added to the casting solution is too strong

Jj leads to viscosity changes. In contrast to the comparative samples, those are produced according to the invention

* y samples A), B) and C) with regard to their viscosity practically independent of the type and amount of the added

Sensitizer or stabilizer and their viscosity values are 39.5, 39 and 38.5. The viscosity of the In addition, emulsions produced according to the invention are approximately the same as that of an emulsion which is produced in an analogous manner

T. is produced, but instead of the sensitizer dispersion, a pure gelatin solution is added

^ was. The comparison solutions E and F already have such a reduced viscosity that they can be poured

^f ". a layer support with these solutions no longer leads to usable photographic layer formation,

which contains a sufficient amount of silver halide. As a result of sedimentation phenomena is low , ~ viscous casting solutions depleted the silver halide in the casting device at the point where the layer substrate

ger immersed in the casting solution, so that with low-viscosity casting solutions only a low-silver halide V stratification is possible

f B eis ρ ie 1 4

To 1000 g of a silver bromide iodine emulsion with a silver halide content of 0.55 Mo! per kg were

Sr 100 ml of a 1% aqueous solution of 4-hydroxy-6-methyI-l, 2 _r 3a-7-tetraazaindene 20 ml of a t%

if aqueous pyrocatechol solution and 50 ml of a 5% sodium salt solution of pentadecylene succinic acid

p glycolide added. The color coupler used was 42 g of the color coupler described in Example 1 in emulsified

/ Form with 21 g of dibutyl phthalate and 2.1 dodecylbenzenesulfonate in 420 ml of 25% gelatin

Jj sets Sensitization was carried out according to the procedure given in Example 3, the comparative sample H with

ΓΙ 190 mg of sensitizer dye III dissolved as a 0.05% solution in a methanol / dimethylformamide mixture

t ' with a volume ratio of 1: 1 and the sample G according to the invention with a sensitizer dispersion according to FIG

s Example 2, containing 190 mg of sensitizer HI, was sensitized. The samples produced in this way were at

40 ⁰ C stored Such storage at 40 ⁰ C in the art, when preparing the baster - * ■ required. During storage of the solution at 40 ⁰ C begießfertigen the Verglcichsansatz H showed substantial SEDE

i mentation phenomena of the dispersed silver halide grains. In contrast to this, the invention

"" according to sample G is much less susceptible to sedimentation.

The silver halide emulsion used in Example 4 is an emulsion with silver halide

Genid grains, the most common grain diameter of which was about 0.55 μm. The percentage of silver halide bodies with the most common grain diameter was around 15%.

In Fi g. 3 is curve 1 as the frequency of the individual grains as a function of their grain diameter in

% shown

B c i s ρ i e I 5

Example 4 was repeated except that the silver halide grains were in the silver bromide iodide emulsion with a grain diameter of 0.6 μm were only present to about 8% and a larger proportion Silver halide grains had a grain diameter of 1 μm to 2 μm. A comparison of the frequency distribution of the two emulsions is shown in FIG. 3. Curve 2 represents the frequency distribution of the silver halide grains of the emulsion used in Example 5, while curve 1, as mentioned, that of the emulsion of Example 4 represents

4 shows the values obtained in the sedimentation measurement. The ordinate shows the removal height in the storage vessel (filling height 40 cm) for the individual test samples and on the abscissa is that of the The silver halide content determined at the individual withdrawal levels, measured as g silver nitrate / kg emulsion. The in F i g. The measurement shown in FIG. 4 was carried out after a standing time of 6 hours. The curves G and H represent the values obtained with the emulsions of Example 4, curves G 'and H' represent the values which were obtained with the emulsions of Example 5. The curves G and G 'provide the samples according to the invention, the comparison samples the curves H and H '.

The comparison shows that the photographic emulsions produced according to the invention are essentially tend to sedimentation phenomena to a lesser extent than the comparison emulsions, independently whether the silver halide emulsions used are relatively liomodisperse or rather heterodisperse are.

Examples t> 0

In the following it is shown that the sensitization method according to the invention in comparison to method of the prior art enables the production of photographic materials which, with regard to their Sensitivity are improved.

To 1 kg of a silver bromide iodide emulsion (silver halide content of 0.3 mol per kg) was added after 4-Hydroxy-6-methyl-1,2,3a-7-tetraazaindcn, a pyrocacechol solution and a sodium salt solution of pentadecylenesuccinic acid! Y! <olids 24 g of the coupler of the formula

NHCOC ₁₃ H ₂₇

^: ·: added in emulsified form with 6 g of dibutyl phthalate and 180 g of a 2.5% strength aqueous gelatin solution.

Sensitization was carried out according to the method given in Example 2, sample I according to the invention with a sensitizer dispersion according to Example 2, containing 45 mg of the sensitizer I, and the comparison sample K was sensitized with 45 mg of sensitizer! Dissolved in methyl alcohol in a ratio of 1: 1000.

The emulsions produced in this way were each hardened with 2 ml of a 5% trialcryl formal solution and applied to ';

a transparent cellulose triacetate substrate. \

After exposure and development of the photographic materials with N-butyl-N-cJ-sulfobutyl-p-phenylenedi- <

amine as a developer at room temperature, the comparison showed that the sample according to the invention by %

13 ° DIN was more sensitive than the comparison sample, which contained the sensitizing dye in methanolic I ?;

Solution contained added. ? ■ '

Further samples L and N according to the invention and comparative samples M and O were prepared in an analogous manner produced with the exception that in comparison to the sample I or to the comparative sample K instead of 45 mg Sensitizer II was used in the case of samples L and M 20 mg and in the case of samples N and O 10 mg.

The evaluation of the sensitometric results shows that, surprisingly, the invention Even when using lower amounts of sensitizer, materials still have a sensitivity>

gain of 1 to 15 ° DIN compared to the corresponding comparative samples K, M and O.

Example 7

Another comparative example shows the advantage of the method according to the invention when using Freeze-dried sensitizer dispersions compared to prior art processes.

To 1 kg of a silver bromide iodide emulsion (0.7 mol of silver halide per kg) were added 120 ml of a 1% strength aqueous solution of 4-hydroxy-6-methyl-1,2.3a-7-tetraazaindene and 1 ml of glycerol were added. The color coupler used was 42 g of the color coupler described in Example 6 in 12 g of dibutyl phthalate in 180 g of a 2.5% strength Gelatin solution added in emulsified form.

Sensitization was carried out with 110 mg of sensitizer II, which was pretreated as follows:

10 g of the sensitizer * II were with 23Jg of the condensation product of naphthalene with formaldehyde and Sulfuric acid (average molecular weight 420) as the sodium salt. 100 g sand and 100 ml water, as in example 1 described, marry. The sand was then filtered off, the filtrate was shock-frozen with liquid nitrogen and the water was sublimated below the melting point of the crystallized aqueous phase Vacuum removed 1 g of the product thus obtained was taken up in 75 ml of water and the 110 mg of the sensitizer corresponding to the amount of the emulsion described above were added.

Working up the emulsion. Manufacture of photographic material, exposure and processing takes place as described in Example 6.

A comparative material Q was produced in an analogous manner, which in contrast to that according to the invention Material P produced has been sensitized with 110 mg of sensitizer. before adding to the emulsion was emulsified in the manner described below:

1 g of sensitizer II was dissolved in a mixture of 50 ml of m-cresol and 25 ml of methyl alcohol, and a solution of 333 g of a 50% aqueous sodium dodecylbenzenesulfonate paste, dissolved in 17 .A ethyl acetate, was added to this solution.

The combined solutions were then in 350 ml of a 6% gelatin solution under intensive Stirring emulsified and the emulsifier was then made up to 100 ml with water. An amount corresponding to 110 mg of sensitizer was added to 1 kg of the above-described silver halide emulsion of this sensitizer emulsion

The comparison shows that the material P produced according to the invention has a ^{sensitivity that is 0} DIN higher than the comparative material Q.

Example 8

'■' ■ '■ 1 kg of a silver bromide iodide emulsion containing 1 mole of silver halide per kg and as a mixture of one

conventional silver bromide iodide emulsion with a converter emulsion in the ratio of 8: 2 was available under.: Application of the cyan color couplers and additives indicated in Example 2 made ready for casting

Sensitization takes place with 130 mg sensitizer V and 130 mg sensitizer III, whereby the sensitizer ft

f> 5 mixture in the case of the inventive sample R according to the method described in Example 2 in a

diluted gelatin solution was used and the sensitizer mixture in the case of the comparative jj

sample S as a 0.05% solution of the seasibilisalor V in dimethylformamide and as a 0.1% solution of the sensitization;

tors III in methyl alcohol was added. ψ

12 §

After the emulsions thus prepared had been poured and hardened with a water-soluble carbodiimide, the photographic materials were developed after exposure in the usual way with N-ethyl-Nvy-oxyethyl-J-methyl-p-phenylenediamine as the developer substance. The sensitometric evaluation showed that in comparison to the sample S of the prior art, the sample R according to the invention a sensitivity gain of DIN and had a color haze that was 0.06 color density units less.

For this purpose 3 sheets of drawings

13th

Claims (8)

Patent claims: 1. Process for the incorporation of photographic additives which are substantially insoluble in water into Silver salt emulsions, the additives having a particle size produced by milling of less than 1 .mu.m and are capable of influencing the sensitometric properties of the silver salt in silver salt emulsions, characterized in that the essentially insoluble in water photographic additive in an aqueous phase in the presence of a monomeric, oligomeric or polymeric alkylarylsulfonate with at least 16 carbon atoms which, when 1 g per liter is used, causes a surface tension of at least 0.038 N / m in water, and that, if necessary ίο immediately, after storage or processing, the dispersion obtained is mixed with a silver salt emulsion will. 2. The method according to claim I _1, characterized in that a sensitizer or stabilizer for silver salt emulsions is used as an additive. 3. The method according to any one of claims 1 and 2, characterized in that the aqueous dispersion prepared by a drying process and, if necessary, stored in a dry state before the Silver salt emulsion is added. 4. The method according to claim 3, characterized in that a freezing or drying method Spray drying is carried out. 5- Process according to claims 1 and 2, characterized in that the aqueous dispersion is a Freeze-eiir spray drying is subjected and the dispersion prepared in this way directly to a liquid silver salt emulsion or, after being introduced into water or an aqueous Sindemite solution, is then admixed with the liquid silver salt emulsion. 6. The method according to any one of claims 1 to 5, characterized in that a silver salt emulsion Silver halide gelatin emulsion is used that has a gelatin to silver ratio of less than 0.7 having 7. The method according to claim 6, characterized in that the silver halide emulsioa. the through Freeze-drying or spray-drying prepared dispersion additive is added directly or in the form of a highly concentrated aqueous dispersion. 8. The method according to any one of claims I to 7, characterized in that the grinding of the additive jo is done with a sand mill.