JP3222266B2 - Method for producing silica particle dispersion - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

The present invention relates to a method of dispersing a compound intended to be incorporated into a photographic silver halide material and to a photographic material having a coating layer incorporating a dispersion produced by such a dispersion method.

In preparing photographic silver halide materials, prior to coating the layers, for example, spectral sensitizers or desensitizers, emulsion stabilizers or antifoggants, development activators or inhibitors, filters, antihalation or It is well known that a number of components, including screening dye color formers, curing agents, surfactants, thickeners, antistatic agents, etc., are mixed in a reaction vessel where the coating composition is prepared.

[0003] Such components are dispersed in the form of finely divided particles when they cannot be formulated with aqueous solutions or solvents that are compatible with water.

[0004] One common and suitable dispersion method involves ball milling the compound in a gelatinous medium. It is also possible to disperse the organic solution of the compound in an aqueous gelatinous medium and subsequently remove the solvent, for example by evaporation under vacuum.

[0005] The alkali-soluble compound can be compounded by a dispersion method based on lowering the pH of an alkaline aqueous solution of gelatin (shifting the pH).

[0006] All of these dispersion techniques have one or more disadvantages. Before and after blending into the gelatinous coating composition, the stability of the aqueous gelatin dispersion is often insufficient,
The result is not reproducible. When using organic solvents, compatibility problems with the aqueous gelatin composition may occur, and the solvents themselves may be ecologically disadvantageous. The ball milling method, which uses metal or glass beads to comminute the components, is a slow dispersing technique, requires relatively complex equipment that is difficult to clean, and creates mechanical and thermal problems. The resulting dispersion has a relatively coarse particle size, and it is difficult to reproduce both the particle size and the particle size distribution.

[0007] The physical and chemical properties improve as the particle size decreases. For example, the coupling activity of the color former is improved, and the light absorption of the dye is improved. Thus, this coarse particle size dispersion has a detrimental effect on photographic properties.

As another disadvantage, aqueous gelatin compositions containing dispersed components are stored as such compositions before they are incorporated into actual coating compositions to form photographic layers, and the gelatin coating compositions Represents an extra amount of gelatin, which in turn increases the binder content of the photographic material and reduces the ability to proceed quickly after exposure due to the increased drying time required.

A first object of the present invention is to provide a simple apparatus for obtaining a fine, stable and reproducible solid particle dispersion of a photographic additive within an acceptable short production time,
Giving improved properties to coating compositions for photographic materials,
To provide an easy ecologically sound method.

[0010] A second object of the present invention is that the fine solid particle dispersion is incorporated in at least one of the layers of a photographic material, and has good physical properties under rapid processing conditions without affecting sensitometric properties. It is an object of the present invention to provide a photographic material which shows stability and chemical stability.

Other objects will become clear from the following description.

According to the present invention , the method includes the following steps.
Characterized as one of the layers of photographic silver halide material
To produce an aqueous dispersion of solid particles of photographic additives for
That a method is provided: a water-soluble organic solvent as an aid if necessary, is water-insoluble and soluble in an alkaline aqueous solution of a compound which is an alkali-soluble, containing colloidal silica sol and a dispersing agent撹
To a solution of拌下, alkali containing the alkali-soluble compound
Aqueous solution and acidic aqueous solution are added at the same time.
PH of the alkaline aqueous solution containing the alkali-soluble compound
The compound in the presence of colloidal silica sol is precipitated from the solution, formed water-soluble salts and organic solvent by precipitation buttocks (when using it) was removed by keeping at a constant value lower than, precipitation by dialysis or ultrafiltration during or after step, or by flocculation and decantation after precipitation step, and further by performing the washing and further decantation Subsequently, you concentrating the dispersion.

The silica and / or dispersant may be present in an aqueous alkaline solution and / or acidic aqueous solution, or may be present in another aqueous alkaline solution and both the aqueous alkaline solution and the acidic aqueous solution are added to the additional aqueous alkaline solution. Good.

[0014] In particular according to the invention, is an alkaline solution of photographic addenda presence and preferably the divided silica particles in the fine pore was neutralized agglutination was prepared or solidified in the presence of a surfactant particles It has been found that by adsorbing the silica particles, a fine, uniform and reproducible dispersion can be produced using a relatively simple apparatus within a reasonable production time of about 1 hour.

Furthermore, according to the present invention, fine silica dispersions of dyes can be prepared, for example as filters, screening or antihalation dyes, for incorporation into at least one of the layers of the photographic material, thereby increasing the efficiency of light absorption. However, it has been found that the required coverage of dye is reduced, and that the decolorization rate in processing the photographic material is high, making it particularly suitable for high speed processing applications.

Further, it has been found that a fine silica dispersion of a color developing agent having a high coupling activity can be produced.

Silica is well known as a suitable hydrophilic binder used in place of gelatin in hydrophilic layers, and more particularly in silver halide emulsion layers. EP Application No. 91.2
As disclosed in U.S. Pat. No. 02082/3, increasing the amount of silica sol used as a protective colloid in the preparation of silver halide emulsions results in acceptable physical stability of the emulsion after coating.

According to the present invention, for example, as a dye, pH
A compound dissolved in an aqueous alkaline solution having a value of at least 8.0, which is soluble in an aqueous alkaline solution, is prepared by partially or entirely adjusting the temperature, concentration, order of addition and rate of addition of the aqueous alkali solution and the acidic aqueous solution in an aqueous silica medium. Mix and precipitate under conditions adjusted to. Preferably, the precipitate is finely dispersed in a stable colloidal medium in order to obtain a compound which is finely dispersed in the aqueous alkali solution and / or the ionizable polymer and / or amphoteric substance and / or surfactant present in the reaction vessel. May be performed in the presence of a dispersant. An alkaline aqueous solution is placed in a reaction vessel and the solution is p
It may be possible to acidify to an H value, but under conditions controlled in a reaction vessel containing silica and / or a dispersant and carefully controlled to a constant pH value, using a double injection technique. It must be recommended that compounds such as dyes precipitate from the solution. Of course, the presence of silica and / or dispersant is not limited to the reaction vessel. Silica may be partially divided into a reaction vessel and a solution to be added to the vessel. Using the so-called “pH-stat”, the pH in the container
It is also possible to measure the values continuously with a glass electrode and to electronically derive the rate of addition of the acidic aqueous solution so that this acidification step can be carried out under completely controlled conditions. Preferred constant values should be low enough to obtain quantitative aggregates of compounds such as dyes, pH values below 6.0 are recommended, and values of about 3.0 are particularly preferred. The rate of addition of the alkaline solution largely depends on the concentration of the alkaline solution, the stirring speed and the constant pH value to be maintained in the reaction vessel. The rate at which the alkaline solution is added to the reaction vessel and / or the rate of agitation in the vessel may be increased during the precipitation process. Even the continuous online manufacturing method is possible given the necessary considerations for constant-acting factors mentioned in this specification. In this case, a third continuous stream of solution, usually present in a vessel, is brought into contact with a small reaction vessel in which the three streams are mixed using a stirrer, followed by on-line normal filtration or filtration. Perform filtration.

According to the chemical structure of the compound to be dispersed, the pKa value of the aqueous solution can be determined and the pH precipitation value can be selected in advance. The preferred addition rate of the aqueous alkali solution also depends on the pH value of the aqueous alkali solution of the compound (s) and the stirring speed in the vessel. Related to the amount of the compound,
The amount of silica present in the reaction vessel may vary from 5/1 to 1/5 by weight.

The precipitated compound produced according to the present invention is very finely divided using this technique and is coated with a protective layer of silica particles adsorbed on or co-precipitated with the compound. This very stable, concentrated dispersion of particles can be stored at room temperature for at least several weeks or months before the components are used in the coating layer of the photographic material.

Obviously, the dispersibility of the components of the silica depends on whether the components are completely ionizable or completely insoluble, p
It largely depends on the difference in H value. If the pH value is sharply determined, very finely divided components with negligible losses can be obtained in highly quantitative yields.

Since the soluble alkaline salt is formed during the neutralization of the alkaline solution, the salt should be removed to improve the stability and coating properties of the hydrophilic layer in which the compound is to be incorporated. Desalting and concentration of the newly generated silica dispersion
Dialysis, ultrafiltration and agglomeration are possible using well-known techniques, the last of which relates to silver halide crystals having silica as a protective colloid, EP application number 517,961 filed on June 11, 1991. It is described in. Ultrafiltration techniques are preferred in the present invention. In about 30 minutes it is possible to obtain a stable silica dispersion concentrated up to about 6% or even about 10% by weight of the compound, higher values being used to increase the viscosity before the addition to the coating composition Not recommended as dilution will be required.

This technique actually saves a great deal of time when compared to the familiar mechanical milling technique, which is performed in the presence of gelatin and a surfactant and takes at least 12 hours and sometimes several days. In addition, fine solid particles of improved quality and more reproducible with a size of about 150 nm are obtained, whereas the mechanical milling techniques described above are very complex, energy consuming, Using equipment that must be thoroughly washed before starting a new batch, more non-reproducible amorphous particles are produced. Furthermore,
There is no need to use an excess amount of organic solvent, so that the technology is particularly preferred from an ecological point of view.

Compounds commonly used in photographic materials are those which give the essential condition that their chemical structure has a pH-dependent, water-soluble property.
Any can be dispersed according to the present invention.

For example, according to the present invention, it can be ionized,
A water-insoluble compound having no soluble group, such as a color developing agent, is dissolved in a minimum amount of an organic solvent and added to an aqueous alkaline solution. This solution is slowly added simultaneously with the acidic solution for neutralization to the reaction vessel containing the stirred aqueous dispersion of silica particles, preferably in the presence of a suitable dispersant. These additions are preferably carried out under partially or wholly controlled stirring conditions of temperature, concentration, order of addition and rate of addition. In order to obtain a finely dispersed compound in a stable colloidal medium, it is recommended to carry out such precipitation in the presence of at least one polymer and / or surfactant in the reaction vessel. As long as the conditions are kept strictly constant in order to obtain a stable and reproducible solid particle dispersion, any combination of bringing the necessary components into contact with each other is of course possible. The term "solid" here relates to "silica particles" which surround and stabilize the water-insoluble photographic additive .

It is clear that this excellent manufacturing technique for forming a stable and uniform "silica particle dispersion" may be applied to each photographic additive .

Conventional silica sols are suitable as essential components for the process according to the invention. A suitable silica sol is
“Syton” silica sol (a registered trademark of Monsanto Inorganic Compounds Division), “Ludox”
Silica sol (a registered trademark of du Pont de Nemours & Co., Inc.), "Nalco" and "Nalcoag" silica sol (a registered trademark of Nalco Chemical), Nissan Chemical K.K. K. "Snowtex silica sol," and "Kieselsol
oi), type (00, 200, 300, 500 and 60)
0 "commercially available, such as (a product of a registered trademark of Bayer AG) can be obtained. Specific surface area of 600m from 100m ² / g ² /
g of colloidal silica are particularly preferred.

It is recommended, but not always necessary, to add an auxiliary dispersant to the reaction vessel during the production stage. The dispersant may be selected from the class of partially ionizable polymers and compounds known as surfactants, and may act as a synergistic co-stabilizer. Any combination may be used to maximize the stability of the resulting organic compound silica particle dispersion.

Suitable co-stabilizers include, as is known, lipophilic moieties such as long chain aliphatic groups or aliphatic-aromatic groups,
A surfactant having a hydrophilic portion such as an anionic or cationic group, an amphoteric group, or a nonionic group such as an ethylene oxide group. They include anionic surfactants containing acid groups such as carboxyl, sulfo, phospho, sulfate or phosphate groups; amino acids, aminoalkyl sulfates, aminoalkyl sulfates or aminoalkyl phosphates, alkyl betaines, and Amphoteric surfactants such as amine-N-oxides; and cationic surfactants such as alkylamine salts, aliphatic, aromatic or heterocyclic quaternary ammonium salts, aliphatic or heterocyclic ring-containing phosphonium or sulfonium salts. Agent included. According to the invention, the surfactant has the function of promoting the dispersion emulsification of the components of the silicic acid during the production. These surface-active compounds may be added, for example, to the reaction vessel or to the aqueous alkali solution of the component to be dispersed, irrespective of the content of the organic solvent, or may be divided into these two solutions. Amphoteric compounds such as 2-N, N, N-trialkylaminoacetic acid compounds are particularly preferred. The dispersant is preferably present in an amount of from 1 to 20% by weight relative to the photographic additive .

The above-described preparation methods include, for example, those used in spectral sensitizing or desensitizing dyes, stabilizers, developing agents or development accelerators, DIR color formers, colored mask color formers, and those used in color photographic materials. Everything normally used in a dissolved or finely divided state in a coating layer of a photographic material such as a color former compound such as a color former or a color former that does not form a color after a coupling reaction with a developing agent compound, a color former precursor, etc. May be applied to produce a fine, stable and uniform silica dispersion of the organic compound of the formula (1).

If the organic compound does not have an ionizable group and is insoluble in an aqueous alkaline solution, it may be added to an alkaline aqueous solution containing colloidal silica particles and preferably an auxiliary co-stabilizing dispersant before adding the auxiliary aqueous solution to the aqueous alkaline solution. The organic compound may be dissolved using an organic solvent. Preferred organic solvents are methyl alcohol, ethyl alcohol, isopropyl alcohol, tetrahydrofuran, dimethylformamide, dioxysan, N-methyl-pyrrolidone, acetonitrile, ethylene glycol, ethyl acetate, and others.

The aqueous solution is made alkaline with a base such as sodium hydroxide. In the neutralization step, an organic acid such as acetic acid, propionic acid and the like, or an inorganic dilute acid such as hydrochloric acid, sulfuric acid or phosphoric acid is used.

Obviously, the dispersibility of the water-insoluble component of the silica is determined by the distribution obtained as a function of the relative amounts of the component, silica and ionizable polymer and / or surfactant present in the reaction vessel. And the degree of agitation applied during the neutralization step. Thus, when this method is fully optimized, it is possible to obtain very finely dispersed components in high quantitative yield and with little loss. The resulting silica dispersion may be concentrated using the techniques described above. It is clear that these very finely divided photographic additives are characterized by very high photographic activity when compared to compounds in gelatinous dispersions made by ball milling and similar techniques. .

In order to be incorporated into a photographic silver halide material,
A non-limiting list of photographic additives from which the dispersions can be prepared according to the present invention is provided below.

A spectral sensitizer having a methine group may be used according to the invention. An example is F. M. "Cyanine Dyes and Related Compounds" by Hamer, 1964, John
It is described in Wiley & Sons. Dyes that can be used for the purpose of spectral sensitization include cyanine dyes, merocyanine dyes, complex cyanine dyes, complex merocyanine dyes, homopolar cyanine dyes, hemicyanine dyes, styryl dyes, and hemioxonol dyes.

Other dyes that do not themselves have spectral sensitizing activity, or certain other compounds that do not substantially absorb visible light, may be incorporated into the silver halide emulsion with the spectral sensitizer. It can have a supersensitizing effect. Suitable supersensitizers that can be added as silica dispersions are described in U.S. Pat.
Heterocyclic compounds having at least one electronegative substituent as described in No. 78, etc., US Pat.
No. 90 and US Pat. No. 3,635,721, etc., and a nitrogen-containing heterocyclic ring-substituted aminostilbene compound,
Examples thereof include aromatic organic acid / formaldehyde condensation products, cadmium salts, and azaindene compounds as described in U.S. Pat. No. 3,743,510.

Compounds that prevent fogging or stabilize photographic properties during the manufacture or storage of photographic elements or during photographic processing may be added to the silver halide emulsion as a dispersion of an antifoggant or stabilizer. By utilizing a silica dispersion of such a component, suitable examples of stabilizers from which the silica dispersion can be prepared, otherwise avoiding the addition of the necessary pH-reducing liquid, are benzothiazolium salts, nitro Imidazole, nitrobenzimidazole, chlorobenzimidazole, bromobenzimidazole, mercaptothiazole, mercaptobenzothiazole, mercaptobenzimidazole, mercaptothiadiazole, aminotriazole, benzotriazole (preferably 5-methyl-benzotriazole), nitrobenzotriazole, mercapto- Especially tetrazole, 1-phenyl-5
-Mercapto-tetrazole, mercaptopyrimidine,
Mercaptotriazine, benzothiazoline-2-thione, oxazoline-thione, triazaindene, tetraazaindene, pentaazaindene, especially Z.
Wiss. Phot. 47 (1952), pp. 2-58, GB-A No. 1203775, GB-A No. 12
09146, JA-Application No. 75-39537,
Triazolopyrimidines such as those described in GB-A1500278, and 7-hydroxy-s-triazolo- as described in US-A-4272017.
And heterocyclic nitrogen-containing compounds such as [1,5-a] -pyrimidine.

These antifoggants or stabilizers can be added to the silver halide emulsion before, during or after chemical ripening, and mixtures of two or more of these compounds can be used.

Other examples include, for example, dimensional stability enhancing compounds for photographic elements, UV absorbers, curing agents, plasticizers, coating aids, antistatic compounds, slipperiness improving compounds, anti-adhesion or reducing compounds, high contrast, Additives such as compounds for improving photographic properties such as sensitization and development acceleration. Preferred development accelerators are polyalkylene derivatives having a molecular weight of at least 400.

Further components which may be incorporated in the hydrophilic layer with the silica dispersion are developing agents such as dihydroxybenzene or derivatives, phenidone and the like, which are used in developing solutions such as benzotriazole and / or indazole or benzimidazole derivatives. And those not combined with other organic compounds.

If necessary, similarly manufactured, for example, U
Aryl-substituted benzotriazole compounds described in SA-3533794, 4-thiazolidone compounds described in U.S. Pat. Nos. 3,314,794 and 3,352,681, benzophenone compounds described in JP-A-2784 / 71, US- A No. 3705805 and No. 3707
No. 375, butadiene compounds described in US Pat. No. 4,045,229, and US Pat.
A silica dispersion of a UV absorber such as the benzoxazole compounds described in A-A-3700455 may be added.

The silica dispersion of the photographic additive prepared according to the present invention may be added to a coating composition for a light-sensitive silver halide emulsion layer or a non-light-sensitive auxiliary layer known in the silver halide photographic art. .

Suitable further additives for improving the dimensional stability of photographic elements containing the silica dispersions of the components described above, for example alkyl (meth) acrylates,
Alkoxy (meth) acrylate, glycidyl (meth)
Polymers of acrylate, (meth) acrylamide, vinyl ester, acrylonitrile, olefin and styrene or acrylic acid, methacrylic acid, α-β-
A dispersion of a water-soluble or poorly-soluble synthetic polymer such as a copolymer of unsaturated dicarboxylic acid, hydroxyalkyl (meth) acrylate, sulfoalkyl (meth) acrylate and styrene sulfonic acid may be added.

The same applies to plasticizers suitable for incorporation in the emulsion layers of the present invention, such as glycols, glycerin,
Or polyvinyl acetate, and polyester acrylate,
The present invention can also be applied to a latex of a neutral film-forming polymer containing an acrylate or methacrylate of a lower alkanol such as polybutyl methacrylate.

The light-sensitive silver halide emulsion may be a conventional type emulsion or an emulsion prepared according to published EP Application No. 392092 using silica as a protective colloid.

When a gelatinous binder is used in the photographic composition, the binder may be an epoxide type hardener, an ethyleneimine type hardener, 1,3-vinylsulfonyl-
Vinyl sulfone type curing agents such as 2-propanol, chromium salts such as chromium acetate and chromium alum, aldehydes such as formaldehyde, glyoxal and glutaraldehyde, N-methylol compounds such as dimethylol urea and methylol dimethylhydantoin, 2,3-dihydroxy -Dioxane derivatives such as dioxane, active vinyl compounds such as 1,3,5-triacryloyl-hexahydro-s-triazine,
It can be cured with a suitable curing agent such as an active halogen compound such as 2,4-dichloro-6-hydroxy-s-triazine and mucohalic acid such as mucochloric acid and mucophenoxychloric acid. These curing agents can be used alone or in combination. The binder can also be cured with a fast-reactive curing agent such as a carbamoylpyridinium salt. The hardener may also be incorporated as a silica dispersion in the hydrophilic layer containing gelatin, provided that hardening proceeds during processing at high pH values during processing. In this case, it is present in the material as a "latent hardener" which is inert when the pH value of the coating is low.

In the case of photographic layer coating solutions, pH values of about 6.5 to 7.0 are measured, but with a considerably higher p
Applying a developing solution having an H value increases the pH value of the photographic layer.

The dispersion technique according to the present invention is useful in most multi-layer photographic coatings, where the transition from one layer to another hinders the photographic properties of each other, and the components that must be non-migrating during coating and drying. Especially suitable for: These components include non-spectral sensitizing dyes. The dye may be used in a photosensitive silver halide emulsion layer as a screening dye, or as opposed to a subbing layer and / or a photosensitive layer adjacent to a photosensitive layer to absorb reflected and scattered light and thereby serve as an antihalation dye. Used as a backing layer on one support side, or used as a topcoat or interlayer to shield special photosensitive layers and prevent undesired exposure, and is therefore referred to as a filter or an absorbing dye, which can be used when necessary for production. Adjust the sensitivity of the element.

Such absorber dyes may be present in one or more filter layers between the silver halide emulsion layers coated on both sides of the transparent support of the dual X-ray recording material in order to improve image scoring. . Imagewise exposure of the recording material proceeds in a cassette between a pair of X-ray intensifying screens, each held in contact with an adjacent silver halide emulsion layer. With this arrangement, the imaging light traverses the support, scatters to some extent and is significantly attenuated, and cannot produce a "brilliant" image in the opposite silver halide emulsion layer.

The dye absorption spectrum should be spectrally approximately equal to the sensitivity spectrum of the corresponding silver halide emulsion in the layer where a sharp image must be reproduced. According to the method of the present invention, the amount of very finely divided silica disperse dye can be reduced due to improved photographic activity. No color stain is observed in the subsequent film, and the dispersion of the non-migratory dye is completely removed under high-speed processing conditions.

The hydrophilic layer containing the silica dispersion according to the invention preferably comprises a thermoplastic resin such as polyethylene terephthalate or a polyethylene-coated paper support.
Any suitable substrate may be coated.

The components made in accordance with the present invention include photographic elements for graphic arts and so-called amateur and professional photography, reversal transfer reversal photographic elements, low and high speed photographic elements, X
Various photographic elements such as wire materials, color materials and the like may be added in a silica-dispersed form.

The following examples illustrate the invention without limiting it.

[0054]

EXAMPLES Comparative Example 1 Comparative Gelatinous Dispersion of Dye 1 The formula is shown below. Dye 1 is used and gelatinized by a ball mill technique that can use glass beads of zirconium oxide to finely grind the dye. A dispersion was prepared. After a total milling time of 6 hours, a dispersion was obtained using 15 g of dye for a total weight of 40 g of aqueous dispersion containing 15 g of gelatin. After the mechanical treatment was completed, 12.5 g of the dispersion was added. As a result, the average particle size was about 65
A very uniform dispersion with 0 nm particles was obtained. The dispersion was named comparative dispersion GEL.

[0055]

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Example 1 Silica Dispersion of Dye 1 The silica dispersion was treated with an aqueous silica sol "Kiesel sol".
sol) in a vessel containing 500 "(a product of Bayer AG) using Dye 1. The pH value was therefore 8.
An alkaline solution prepared by dissolving Dye 1 in deionized water adjusted to 0 was added to the silica sol at a constant rate together with the sulfuric acid solution. The sulfuric acid solution was added at a controlled addition rate as determined by the starting pH of 3.0 when initially fed to the reaction vessel.

The method was performed at room temperature on the reaction vessel, acidic and alkaline solutions. The reaction mixture was stirred during the addition by double injection. After the precipitation was completed, ultrafiltration was started. The silica dispersion of Dye 1 thus produced is referred to as “SILI
CA A ”. Nanosizer measuring device“ Coult
er Nano-Sizer ™ ”was used to measure the average particle diameter of 330 nm.

Example 2 Silica Sol and Surfactant 1 of Dye 1 in a Reaction Vessel
Dispersion in a mixture with SILICA B was prepared in the presence of an amphoteric surfactant (Surfactant 1) corresponding to the formula shown below. During the preparation of the dispersion, S was added except that surfactant 1 was additionally present in the reaction vessel.
The method for ILICA A was followed. As a result of measurement using a Nanosizer, the average particle diameter was 320 nm.

[0059]

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COMPARATIVE EXAMPLE 2 Dispersion of Dye 1 in Surfactant 1 A dispersion named SURF COMP was prepared by placing surfactant 1 in place of silica sol 1 in a reaction vessel. %, Prepared in the same manner as SILICA A, except that it was added and present in an amount of 1 g.

Example 3 Silica Dispersion of Dye 2 An aqueous silica sol "Kiesel"
A silica dispersion was prepared in a vessel containing sol 500 "(a product of Bayer AG), with a pH value of 11.
The alkaline solution of Dye 2 adjusted to 5 was added at a constant addition rate, while the citric acid solution was added at a constant pH value of 3.0. This dispersion, named SILICA C, had an average particle diameter of 175 nm.

[0062]

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Example 4 Dispersion of Dye 2 in a Reaction Vessel in a Mixture of Silica and Surfactant 1 A dispersion named SILICA D was mixed with amphoteric surfactant 1
Prepared in the presence of 1% by weight during the production of the dispersion
Was added to the reaction vessel and surfactant 1 was present in the reaction vessel, except that SILICA was used.
The same method as in C was followed. An average particle diameter of 250 nm was obtained.

[0064] The dye 2 with an alkaline solution containing Example 5 Silica sol,
Dispersion in a reaction vessel in a mixture of silica and surfactant 1 This dispersion was named SILICA E, the only difference being the use of a 10-fold diluted silica sol, but similar to the dispersion SILICA D Prepared by the method. The pH value of the alkaline solution was adjusted to 11.5.

Table 1 summarizes the data evaluated for the various dispersions and includes a qualitative analysis of their stability, degree of uniformity and measurements of dispersed particle size. The stability of the dispersion was qualitatively evaluated and the decision given was "very good" depending on the degree of settling of the solid particles left in the beaker at room temperature for at least 48 hours in dispersed form. "," Good "or" poor ". The size of the dispersed particles is determined by the “Nanosizer” measuring device “Coulter Na
Measured using a no-Sizer TM.The uniformity was qualitatively measured by observing a photograph of the dispersed particles using a "scanning electron microscope" and was "very uniform", "uniform", "non-uniform". Alternatively, it was qualitatively expressed as "very heterogeneous".

Table I Evaluation of Various Dispersions Dispersion Name Stability Particle Size (nm) Uniformity GEL COMP (Comparative Example) “Poor” 650 nm “Very Non-uniform” SILICA A (Invention) “Good” 330 nm "homogeneous" SILICA B (invention) "very good" 320 nm "very uniform one" SURF COMP (comparative example) "very bad" not measurable "unexplained" SILICA C (invention) "good" 175 nm "homogeneous" SILICA D (Invention) “Very good” 250 nm “Very uniform” SILICA E (Invention) “Very good” 220 nm “Very uniform”

[0067] In accordance with the present invention, in the absence of it or the presence of a surfactant added to the sheet silica sol, by generating a "solid Shikari dispersion", in a state where the organic solvent is not present, very fine Table 1 clearly shows that it is possible to obtain very stable, very uniform dispersed particles.

Example 6 Dispersion of Color Developing Compound 1 A solution was prepared by dissolving Color Developing Compound 1 having the formula shown below in ethanol / water (1: 1), and the pH was adjusted with sodium hydroxide. Adjusted to zero. The production method described in Example 1 above was used in the presence of silica sol and surfactant 1 as a co-stabilizer (see 1 in Table II);
It was applied in the presence of the sol (see 2) and in the presence of surfactant 1 as sole stabilizer (see 3). The corresponding "stability", "uniformity" and "particle size" ratings are shown in Table II. The terminology is defined above. Organic solvents can be removed by dialysis.

Table II Evaluation of dispersion of color former compound 1 No. Stability Particle size (nm) Uniformity 1 (silica + co-stabilizer) “very good” 75 nm “uniform” 2 (silica) “good” 80nm “uniform” 3 (co-stabilizer) “poor” unmeasurable “unexplainable”

Table II clearly shows that very fine, very stable and very uniform non-dispersible particles are obtained in the presence of the silica sol and a surfactant present as a co-stabilizer.

[0071]

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Example 7 Incorporation of Silica Dye Dispersion into Photographic Material Using Dye 2, a gelatinous dispersion was prepared as described for Dye 1 in Comparative Example 1 and named GEL COMP2.

The dispersion according to the invention, termed SILICA D, whose preparation is described in Example 4 and whose evaluation is given in Table I, is incorporated into the filter layer of the X-ray material and the compounded GEL Compared to COMP2. The production method and coating method are shown below.

Chromium (III) acetate as a hardener and additional gelatin in an amount such that the total amount of gelatin in each filter dye layer is the same are added at a temperature of 36 ° C. and a pH of 6.1.
Was added to the dye dispersion prepared above.

[0075] become respectively when dye coverage is in the case of SILICA D dispersion 0.025g ^/ m 2, GEL COMP2 dispersion 0.075 g / ^{m 2} on each side, and gelatin coverages 1 g ^{/ m} 2, Hardener coating amount of 0.016
g / m ² , the dispersion was 175 μm thick.
Was coated on both sides of a polyethylene terephthalate film support and dried.

On both sides of a polyethylene terephthalate film support, the dye, coated in an anti-crossover layer, is overcoated with an emulsion and a protective layer, and the silver halide emulsion is not spectrally sensitized.

Samples of these coatings were illuminated for 0.1 second using a continuous wedge of blue light and processed in a 38 second processing cycle applied for high speed processing of X-ray materials, as described below. Crossover was measured.

Therefore, a double-sided coated sample was prepared by using a single blue light-emitting screen (CURIX BLUE: Agfa trademark).
And white paper used in place of the second screen. This film screen element, together with its luminescent screen, is directed to an X-ray tube, and then various doses (log
The X-ray of E) was irradiated. After processing these samples in a high speed processing cycle of 38 seconds, the minimum dose (log E) required to obtain a density of 0.5 on the fog is determined by the front layer (log E front) and the rear layer (log E). Back) were measured separately. Then the% crossover was calculated according to the following formula:

% Crossover = 100 / fog prevention (log E back-log E front)

The density as a function of the light dose was measured, whereby the following sensitometric properties were determined: fog level (with an accuracy of 0.001 density), the relative speed when the density on the fog is 1 S (gelatin dispersion GEL C
The sample with OMP2 was set at a speed of 100), the maximum density DMAX and the contrast calculated between the densities 0.25 and 2.0 on the fog.

Table II shows the results of the photographic test. The table shows that the crossover percentage obtained with the SILICA D dispersion filter layer is lower than the value obtained with the GEL COMP2 dispersion even when the coverage of the dye dispersion is reduced by a factor of 3. In addition, no residual color was observed.

Table III Evaluation of% Crossover of Coated Filter Layer Filter Dye Dispersion Calibration Speed Contrast DMAX% Crossover GEL COMP2 9 100 250 3.325 31.5 SILICA D 10 103 251 3.314 26.1

In the above-mentioned anti-crossover layer, instead of the gelatin binder, another non-gelatin layer having a low swelling degree and a high drying rate, such as a polyvinyl alcohol binder, can be used successfully.

──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Hendrick Lambrec 27 Septestrat, Mortseel, Belgium 27 Inside Agfa Geverth na Mroseze Bennoutchap (56) References JP-A-3-5748 (JP, A JP-A-1-167368 (JP, A) (58) Fields investigated (Int. Cl. ⁷ , DB name) G03C 1/06 502

Claims (7)

(57) [Claims] 1. A photographing method comprising the following steps :
For photography to be incorporated into one of the layers of true silver halide material
Method of manufacturing an aqueous dispersion of solid particles of additive: a water-soluble organic solvent as an aid if necessary, is water-insoluble and soluble in an alkaline aqueous solution of a compound is an alkali-soluble, colloidal silica sol and a dispersing agent Dissolved under stirring
An alkaline aqueous solution containing the alkali-soluble compound
And an acidic aqueous solution at the same time, while the pH is
Lower than the pH of alkaline aqueous solution containing re-soluble compounds
There the compound in the presence of colloidal silica sol is precipitated from the solution by keeping at a constant value, which is formed a water-soluble salt and an organic solvent by precipitation buttocks (when using it) is removed and the precipitation step during or by subsequent dialysis or ultrafiltration, or by flocculation and decantation after precipitation step, and further by performing the washing and further decantation Subsequently, concentrating the dispersion. 2. The method according to claim 1, wherein the constant pH value is adjusted to less than 6.0. 3. The method according to claim 1, wherein the dispersant is a partially ionizable polymer, a surfactant or a combination thereof. 4. The method according to claim 1, wherein said photographic additive is present in a weight ratio of 1: 5 to 5: 1 with respect to said colloidal silica sol. 5. The method according to claim 1 , wherein the dispersant is used in an amount of 1 to 20 with respect to the compound.
A method according to any of the preceding claims, wherein the method is present in an amount of% by weight. 6. The photographic additive is a dye, a stabilizer, a colored or uncolored color former, a color former precursor, a developing agent, a development activator, a curing agent or a desensitizer.
6. The method according to any one of claims 1 to 5. 7. A photograph in which a solid particle dispersion produced by the method according to claim 1 is blended with a hydrophilic layer before or during coating a hydrophilic layer on at least one surface of a support. material.