EP0267522A2 - Photographic recording material - Google Patents

Abstract

R¹ und R² einzeln gleich oder verschieden, jeweils eine Alkylgruppe mit 1 bis 8 Kohlenstoffatomen oder eine gegebenenfalls mit einer Alkylgruppe mit 1 oder 2 Kohlenstoffatomen oder mit einem Halogenatom substituierte Aryl-oder Aralkylgruppe, oder zusammen die zur Vervollständigung eines gegebenenfalls mit einer Alkylgruppe mit 1 oder 2 Kohlenstoffatomen oder mit einem Halogenatom substituierten heterocyclischen Ringes, z.B. eines Piperidin-oder Morpholinringes erforderlichen Atome,
R³ ein Wasserstoffatom oder eine Alkylgruppe mit 1 oder 2 Kohlenstoffatomen,
n 0 oder 2.A photographic recording material contains in at least one binder layer a dispersion of hardened particles of a complex coacervate (packet emulsion), the particles of which are hardened with a hardening agent of the following formula I.

R ¹ and R ² individually the same or different, in each case an alkyl group with 1 to 8 carbon atoms or an aryl or aralkyl group optionally substituted with an alkyl group with 1 or 2 carbon atoms or with a halogen atom, or together to complete an optionally with an alkyl group 1 or 2 carbon atoms or heterocyclic ring substituted with a halogen atom, for example a piperidine or morpholine ring,
R ^{3 represents} a hydrogen atom or an alkyl group with 1 or 2 carbon atoms,
n 0 or 2.

Description

The invention relates to a photographic recording material having at least one binder layer and a dispersion of particles of a complex coacervate contained therein, which are hardened with a special hardening agent. The said particles may contain photosensitive silver halide and / or any other photographically active or useful compound. In a preferred embodiment, said recording material is a color photographic recording material and said particles contain light-sensitive silver halide and a color former.

The use of so-called mixed grain or packet emulsions in photography, especially color photography, has long been known. The goal was always to simplify the otherwise multi-layered structure and thereby to obtain recording materials that could be produced more cost-effectively. This could be achieved by combining several so-called packet emulsions with silver halide of different spectral sensitivity and spectrally assigned color formers in a uniform layer. Such a packet emulsion consists of particles ("packets") dispersed in a binder phase in which a light-sensitive silver halide of a particular spectral sensitivity and the spectrally assigned color former, e.g. a color coupler or a color releaser are summarized in such a way that there is also a spatial assignment between them and is also retained if the packet emulsion in question is mixed with packet emulsions of other spectral sensitivity to form so-called mixed-grain emulsions ("mixed packet emulsions"). Such mixed grain emulsions and methods for their preparation are described, for example, in US Pat. No. 2,698,794. This method has also already been proposed for heat development processes (DE-A-3 232 674, DE-A-3 510 685).

A method for producing a packet emulsion in which a color-forming substance is incorporated by complex caacervation is described, for example, in US Pat. Nos. 3,276,869 and 3,396,026. In addition, the production of microcapsules by complex coacervation is described, for example in "Microcapsule Processing and Technology" by Asaji Kondo, Marcel Dekker Inc., New York u. Basel, 1979, pages 70 ff.

The preparation of the packet emulsion by complex coacervation is generally carried out by one of the following two methods.

According to the first method, hydrophilic colloids each selected from a first group and a second group of hydrophilic colloids as defined below are mixed in an appropriate ratio, and an aqueous solution thereof is prepared in a concentration of 1 to 4%. The temperature of the solution is kept in the range of 35 to 60 ° C and the pH is kept above 5.5. The pH is reduced by adding an acid to cause coacervation.

According to the second method, a temperature (not less than 35 ° C.) and a pH (not more than 5.5) are maintained under conditions under which the coacervation can take place, and an aqueous hydrophilic solution of the colloid mixture with a concentration of at least initially 6% is diluted by adding warm water until the concentration suitable for coacervate formation is reached.

Regardless of the method chosen, complex coacervation results in a large reduction in the volume of the binder and the substances dispersed therein compared to the volume of the diluted continuous phase of the hydrophilic colloid not included in the coacervation. It is therefore expedient to separate the coacervate from the dilute continuous phase of the colloid and thereby concentrate it. This can be done in a known manner by filtering, decanting or centrifuging. In addition, the package emulsion obtained can be atomized for complete drying, for example using spray drying methods, such as are known for the production of microcapsules.

It is furthermore expedient to harden the particles of the packet emulsion by using known hardening agents in order to stabilize them mechanically and to ensure better redispersibility.

Examples of hardening agents which have hitherto been used to prepare packet emulsions include chromium salts (for example chromium alum, chromium acetate), aldehydes (for example formaldehyde, glyoxal, glutaraldehyde), N-methylol compounds (for example dimethylolurea, methyloldimethylhydantoin), dioxane derivatives (for example 2,3-dihydroxydioxane) ), active vinyl compounds (for example 1,3,5-triacryioythexahydro-s-triazine, 1,3-vinylsulfonyl-2-propanol), active halogen compounds (for example 2,4-dichloro-6-hydroxy-s-triazine), and mucohalogenic acids (e.g. mucochloric acid, mucophenoxychloric acid). These curing agents can be used singly or as a mixture thereof.

A critical point in the process engineering of the production of very fine packet emulsions (particle size (5 µm) is the concentration step (eg centrifuging). There is generally a great danger in the formation of particle agglomerates (= agglomeration of separate packet particles into larger particles), which are not This danger increases steadily with decreasing particle size and is particularly critical in the particle size range <5 µm.

The above-mentioned hardening agent used so far has the disadvantage that they either generally harden the gelatin very slowly (such as aldehydes, N-methylol compounds etc.) or have a slowed down kinetics at the coacervation pH (such as vinylsulfonyl compounds).

In the concentration step, this usually causes the formation of larger agglomerate particles by gluing individual packet particles. The slowly progressive hardening of these agglomerates then prevents rehomogenization.

The hardening with chromium salts, which is known as the standard method, usually causes the formation of larger agglomerate particles even before the concentration, presumably through a kind of flocculant effect, and thus noticeably reduces the quality of very fine packet emulsions.

The same negative influence on the particle size distribution is also caused by substances which harden very quickly, such as carbodiimides, although the cause does not appear to be clear here.

The invention is based on the object of providing a dispersion of hardened binder particles for photographic recording materials which can be easily concentrated and which is distinguished by improved rehomogenizability after concentration.

worin bedeuten:

• R¹ und R² einzeln gleich oder verschieden, jeweils eine Alkylgruppe mit 1 bis 8 Kohlenstoffatomen oder eine gegebenenfalls mit einer Alkylgruppe mit 1 oder 2 Kohlenstoffatomen oder mit einem Halogenatom substituierte Aryl-oder Aralkylgruppe, oder zusammen die zur Vervollständigung eines gegebenenfalls mit einer Alkylgruppe mit 1 oder 2 Kohlenstoffatomen oder mit einem Halogenatom substituierten heterocyclischen Ringes, z.B. eines Piperidin-oder Morpholinringes erforderlichen Atome,
• R³ ein Wasserstoffatom oder eine Alkylgruppe mit 1 oder 2 Kohlenstoffatomen,
• n 0 oder 2.

The invention relates to a photographic recording material having at least one binder layer and a dispersion of hardened particles of a complex coacervate contained therein, characterized in that the particles of the complex coacervate contain at least one proteinaceous polymeric binder containing carboxyl groups and amino groups and with a hardening agent of the following formula I. are hardened.

in which mean:

• R ¹ and R ² individually the same or different, in each case an alkyl group with 1 to 8 carbon atoms or an aryl or aralkyl group optionally substituted with an alkyl group with 1 or 2 carbon atoms or with a halogen atom, or together to complete an optionally with an alkyl group 1 or 2 carbon atoms or heterocyclic ring substituted with a halogen atom, for example a piperidine or morpholine ring,
• R ^{3 represents} a hydrogen atom or an alkyl group with 1 or 2 carbon atoms,
• n 0 or 2.

Such curing agents are described for example in DE-A-24 39 551. Examples of such curing agents (H-) are listed below:

The curing agent, based on the curable binder, is normally used in a ratio of 0.05: 1 to 0.2: 1, preferably approximately in a ratio of 0.1: 1. It is preferably used as an aqueous solution, e.g. as a 1 to 5%, preferably 2% solution. The hardening agent is expediently added during the actual coacervation step or afterwards and before the concentration.

The hydrophilic colloids that can be used in complex coacervation can be divided into two groups. The first group includes compounds having at least one nitrogen atom; an aqueous solution thereof has a negative charge at a pH higher than its isoelectric point and a positive charge at a pH lower than its isoelectric point (ie a cationic compound or a cationic polymer) . Examples of these compounds include protein-like polymeric binders containing carboxyl groups and amino groups, such as gelatin, casein, albumin. The second group includes compounds of which an aqueous solution always has a negative charge regardless of pH (i.e. an anionic compound). Examples of these compounds include natural colloids, such as sodium alginate, gum arabic, agar agar, pectin, konjac, synthetic polymers with acidic groups or their alkali salts, such as copolymers of vinyl methyl ether or ethylene and maleic anhydride, carboxymethyl cellulose, polyvinyl sulfonic acid or condensation products of naphthalenesulfonic acid and formalin. Preferred examples of anionic polymers that can be used in the present invention include compounds having repeating units that contain carboxylate and / or sulfonate groups and have a molecular weight of not less than 1,000, preferably not less than 3,000. Of the compounds belonging to these two groups, gelatin, agar agar, sodium alginate can be gelled by cooling. Gelatin is particularly suitable for the production of the packet emulsion since it can be gelled by cooling and easily hardened with a hardening agent.

A combination of gelatin and an anionic polymer is therefore preferably used to carry out the complex coacervation. The amount of colloidal substances used varies depending on the charge density of the substances at the time of coacervate formation. However, the colloid of one group is generally used in an amount ranging from 1/20 to 20 times the amount by weight of the colloid of the other group. A weight ratio of 0.5: 1 to 4: 1 is preferred, for example in a combination of gelatin and gum arabic.

The following four conditions are required to effect complex coacervation.

First, the concentration of the hydrophilic colloid in both the first group and the second group must be in the range of 0.5 to 6%, preferably 1 to 4%.

Second, the pH must not be above 5.5. The size of the packet emulsion particles largely varies depending on the pH value, but also fundamentally on the degree of mixing. The optimal pH varies depending on the type of colloid used, but is in most cases in the range from 5.2 to 4.0, preferably from 5.0 to 4.5. The size of the packet emulsion particles used is usually in the range from 1 to 100 µm, preferably from 2 to 60 µm and particularly preferably from 5 to 30 µm.

Third, the temperature of the system must be higher than the solidification temperature of the aqueous colloid solution. In the case of gelatin, the temperature must not be below 35 ° C and is preferably in the range from 40 to 55 ° C.

Fourth, the amount of co-existing inorganic salt must not exceed a certain critical value that is characteristic of the type of salt.

The complex coacervates are then hardened with a hardening agent of the general formula I. The complex coacervate obtained remains fully rehomogenizable when cured with the curing agent according to the invention and has particles with a comparatively narrow particle size distribution and an average particle size (diameter) in the range from 0.5 to 20 μm, preferably 2 to 10 μm.

With the aid of the complex coacervates according to the invention, photographic additives of the most varied types, such as light-sensitive substances or color formers, but also other desired photographically active or useful compounds such as developer substances, antioxidants, UV absorbers and light stabilizers, stabilizers, development inhibitors or accelerators, and their precursor compounds can be used , individually or in any combination with one another, disperse in photographic binder layers. The substances in question are present when the complex coacervation is carried out and are therefore incorporated together with the binder into the particles of the complex coacervate or the packet emulsion. The photographic additives in question can be solids or compounds that are in molten or dissolved form. Complex coacervates can also be prepared which contain both light-sensitive silver halide, optionally in combination with essentially non-light-sensitive organic silver salt, and also a color former such as a color coupler or color releaser, or a bleachable dye.

The use of packet emulsions also enables, according to the invention, the combination of several emulsion components of different spectral sensitivity, including the spectrally assigned color formers in a single binder layer, without losing the spectral assignment and thereby causing a color falsification. This is possible because the degree of exposure of a particular silver halide particle becomes almost exclusively the determining factor for the degree of dye formation from the color former which is in the same coacervate particle (package) as the silver halide. The use of packet emulsions thus enables a blue-sensitive, a green-sensitive and a red-sensitive silver halide emulsion and the spectrally assigned color formers in each case to be accommodated in the same binder layer, without fear of serious color falsification.

The substances contained in the hardened particles of the complex coacervate can be silver halide, which consist of silver chloride, silver bromide, silver iodide or mixtures thereof and have a particle size between 0.02 and 2.0 µm, preferably between 0.1 and 1, Can be 0 µm. It can be in the form of an unsensitized silver halide or it can also be chemically and / or spectrally sensitized by suitable additives. The amount of light-sensitive silver halide in the respective layer can be between 0.01 and 5.0 g per m ² , or even more. For emulsion systems which consist of a mixture of silver halide and organic silver salt, the amount of silver halide used is mainly in the upper range, preferably 0.25 to 1.0 g / m ² for each emulsion fraction.

The essentially non-light-sensitive silver salt which may be present in the particles can be, for example, a silver salt which is comparatively stable with respect to light, for example an organic salt act silver salt. Suitable examples include the silver salts of aliphatic or aromatic carboxylic acids and the silver salts of nitrogen-containing heterocycles; also silver salts of organic mercapto compounds.

Preferred examples of silver salts of aliphatic carboxylic acids are silver behenate, silver stearate, silver oleate, silver laurate, silver caprate, silver myristate, silver palmitate, silver maleate, silver fumarate, silver tartrate, silver furoate, silver linolate, silver adipate, silver sebacate, silver succinate, silver acetate or silver acetate. The carboxylic acids on which these silver salts are based can be substituted, for example, by halogen atoms, hydroxyl groups or thioether groups.

Examples of Sibler salts of aromatic carboxylic acids and other compounds containing carboxyl groups include silver benzoate, silver 3,5-dihydroxybenzoate, silver o-methylbenzoate, silver m-methylbenzoate, silver p-methylbenzoate, silver 2,4-dichlorobenzoate, silver acetamidobenzoate, silver gallate , Siertertannate, silver phthalate, silver terephthalate, silver salicylate, silver phenylacetate, silver pyromellinity, silver salts of 3-carboxymethyl-4-methyl-4-thiazolin-2-thione or similar heterocyclic compounds. Silver salts of organic mercaptans, e.g. the silver salts of 3-mercapto-4-phenyl-1,2,4-triazole, 2-mercaptobenzimidazole, 2-mercapto-5-aminothiadiazole, 2-mercaptobenzothiazole, 2-mercaptobenzoxazole, 2-mercaptooxadiazole, mercaptotriazine, thioglycolic acid, and also the sili-glycolic acid of dithiocarboxylic acids, such as the silver salt of dithioacetate.

The silver salts of compounds having an imino group are also suitable. Preferred examples include the silver salts of benzotriazole and its derivatives, e.g. Silver salts of alkyl and / or halogen-substituted benzotriazoles, such as: the silver salts of methylbenzotriazole, 5-chlorobenzotriazole, and also the silver salts of 1,2,4-triazole, 1-H-tetrazole, carbazole, saccharin and silver salts of imidazole and the like Derivatives.

The application amount of essentially non-light-sensitive silver salt according to the present invention is in the respective layer between 0.05 and 5 g / m ² . The substantially non-photosensitive silver salt and the photosensitive silver salt can furthermore be present in the coacervate particles next to one another as separate particles or in a combined form which can be produced, for example, by treating an essentially non-photosensitive silver salt in the presence of halide ions, whereby the Surface of the particles of the essentially non-photosensitive silver salt by double reaction (conversion) form light-sensitive centers of light-sensitive silver halide. Please refer to US-A 3-457 075.

The essentially non-light-sensitive silver salt can represent a reservoir for metal ions, which are reduced to elemental silver during the heat development that may be carried out in the presence of a reducing agent under the catalytic influence of the imagewise exposed silver halide and thereby serve as an oxidizing agent (for the reducing agent present).

Other possible components in the coacervate particles are color formers, e.g. Color couplers that provide a more or less diffusion-resistant dye during development, or color releasers that release a diffusible dye during development. For example, the coacervate particles of the same packet emulsion can contain one or more color couplers, which in the latter case preferably result in approximately the same color during color development.

Color couplers for producing the blue-green partial color image are generally couplers of the phenol or a-naphthol type; suitable examples of this are described in EP-A-0 028 099, EP-A-0 067 689, EP-A-0 175 573 and EP-A-0 184 057.

Color couplers for producing the purple partial color image are generally couplers of the 5-pyrazolone, indazolone or pyrazoloazole type; suitable examples of this are described in DE-A-1 547 803, DE-A-2 408 665, GB-A-1 247 493, EP-A-0 176 804.

Color couplers for producing the yellow partial color image are generally couplers with an open-chain ketomethylene group, in particular couplers of the a-acylacetamide type; suitable examples of these are a-benzoylacetanilide couplers and a-pivaloylacetanilide couplers as described in US Pat. No. 3,265,506, DE-A-2,456,076.

The color couplers can be 4-equivalent couplers, but also 2-equivalent couplers. As is known, the latter are derived from the 4-equivalent couplers in that they contain a substituent in the coupling site which is split off during the coupling. The 2-equivalent couplers include both those that are practically colorless and those that have an intense intrinsic color that disappears when the color is coupled or is replaced by the color of the image dye produced (mask coupler). In principle, the known white couplers are also to be counted among the 2-equivalent couplers, but they essentially result in colorless products on reaction with color developer oxidation products. The 2-equivalent couplers also include those couplers which contain a detachable residue in the coupling point, which is the result of reaction with color developer oxidation products is released, either directly or after one or more other groups have been split off from the primary split off residue (for example DE-A-2 703 145, DE-A-2 855 697, DE-A-3 105 026, DE -A-3 319 428), exhibits a certain desired photographic activity, for example as a development inhibitor or accelerator. Examples of such 2-equivalent couplers are the known DIR couplers as well as DAR or. FAR coupler.

Suitable DIR couplers are described, for example, in GB-A-953 454, DE-A-1 800 420, DE-A-2 015 867, DE-A-2 414 006, DE-A-2 842 063, DE-A -3 427 235.

Suitable DAR or FAR couplers are described, for example, in DE-A-3 209 110, EP-A-0 089 834, EP-A-0 117 511, EP-A-0 118 087.

Since the DIR, DAR or. FAR couplers mainly want the effectiveness of the residue released during the coupling and the color-forming properties of these couplers are less important, such DIR, DAR or. FAR couplers are suitable which, when coupled, result in essentially colorless products, as described, for example, in DE-A-1 547 640.

The cleavable residue can also be a ballast residue, so that when reacting with color developer oxidation products coupling products e.g. Dyes can be obtained which are diffusible or at least have a weak or restricted mobility, as described, for example, in US Pat. No. 4,420,556.

High molecular weight color couplers are described, for example, in DE-C-1 297 417, DE-A-2 407 569, DE-A-3 148 125, DE-A-3 217 200, DE-A-3 320 079, DE-A- 3 324 932, DE-A-3 331 743, DE-A-3 340 376, EP-A-27 284, US-A-4 080 211. The high molecular weight color couplers are generally produced by polymerizing ethylenically unsaturated monomeric color couplers . However, they can also be obtained by polyaddition or polycondensation.

If the color former contained in the coacervate particles is a color releasing agent, then this can be a variety of connection types, all of which are distinguished by a linkage which is redox-dependent in terms of their binding strength and which links a dye residue to a carrier residue containing a ballast residue.

In this context, a summary of the subject area in Angew. Chem. Int. Ed. Engl. 22 (1983), 191-209, in which the most important of the known systems are described.

Redox-active color releasers of the formula have proven to be particularly advantageous
BALLAST - REDOX - DYE,
in what mean
BALLAST a ballast remnant
REDOX is a redox-active group, i.e. a group that can be oxidized or reduced under the conditions of alkaline development and, depending on whether it is in the oxidized or in the reduced state, is subject to different degrees to an elimination reaction, a nucleophilic displacement reaction, a hydrolysis or another cleavage reaction with the result that the rest of DYE is split off, and
DYE the rest of a diffusible dye, for example a yellow, purple or cyan dye, or the rest of a dye precursor.

Such residues are to be regarded as ballast residues which make it possible to store the color releasers according to the invention in a diffusion-resistant manner in the hydrophilic colloids usually used in photographic materials. Organic radicals which generally contain straight-chain or branched aliphatic groups with generally 8 to 20 C atoms and optionally also carbocyclic or heterocyclic optionally aromatic groups are preferably suitable for this purpose. With the rest of the molecule these residues are either directly or indirectly, e.g. connected via one of the following groups: -NHCO-, -NHS02-, -NR-, where R is hydrogen or alkyl, -0-or -S-. In addition, the ballast residue can also contain water-solubilizing groups, e.g. Sulfo groups or carboxyl groups, which can also be in anionic form. Since the diffusion properties depend on the molecular size of the total compound used, it is sufficient in certain cases, e.g. if the total molecule used is large enough to use shorter-chain residues as ballast residues.

Redox-active carrier residues of the BALLAST-REDOX structure and corresponding color releasers are known in a wide variety of embodiments. A detailed description can be omitted here with regard to the overview article in the app. Chem. Lnt. Ed. Engl. 22 (1983) 191-209.

For the sake of explanation only, a few examples of redox-active carrier residues are listed below, from which a dye residue is split off in accordance with an image-related oxidation or reduction:

The groups enclosed in brackets are functional groups of the dye residue and are separated together with this from the remaining part of the carrier residue. The functional group can be a substituent which can have a direct influence on the absorption and, if appropriate, complex formation properties of the released dye. On the other hand, the functional group can also be separated from the chromophore of the dye by an intermediate link or a link. Finally, the functional group together with the intermediate member may also be of importance for the diffusion and pickling behavior of the released dye. Suitable intermediate members are, for example, alkylene or aryl groups.

In principle, the residues of dyes of all dye classes are suitable as dye residues insofar as they are sufficiently diffusible to be able to diffuse from the light-sensitive layer of the light-sensitive material into an image-receiving layer. For this purpose, the dye residues can be provided with one or more alkali-solubilizing groups. Suitable alkali-solubilizing groups include carboxyl groups, sulfo groups, sulfonamide groups and aromatic hydroxyl groups. Such alkali-solubilizing groups can already be pre-formed in the dye releasers used according to the invention or only from the cleavage of the dye residue from the. result in carrier residues with ballast groups. The following are mentioned as dyes which are particularly suitable for the process according to the invention: azo dyes, azomethine dyes, anthraquinone dyes, phthalocyanine dyes, indigo dyes, triphenylmethane dyes, including those dyes which are complexed or complexable with metal ions.

The residues of dye precursors are to be understood as the residues of those compounds which, in the course of photographic processing, in particular under the conditions of heat development, be it by oxidation, be it by coupling, by complex formation or by exposure of an auxochromic group in a chromophoric system , for example by saponification, can be converted into dyes. Dye precursors in this sense can be leuco dyes, couplers or dyes that are converted into other dyes during processing. Unless a distinction between dye residues and the residues of dye precursors is essential, the latter should also be understood below as dye residues.

• US-A-3 227 550, US-A-443 939, USA-A-3 443 940, DE-A-19 30 215, DE-A-22 42 762, DE-A-24 02 900, DE-A-24 06 664, DE-A-25 05 248, DE-A-25 43 902, DE-A-26 13 005, DE-A-26 45 656, DE-A-28 09 716, DE-A-28 23 159, BE-A-861 241, EP-A-0 004 399, EP-A-0 004 400, DE-A-30 08 588, DE-A-30 14 669, GB-A-80 12 242.

Suitable color releasing agents are described, for example, in:

• US-A-3 227 550, US-A-443 939, USA-A-3 443 940, DE-A-19 30 215, DE-A-22 42 762, DE-A-24 02 900, DE-A -24 06 664, DE-A-25 05 248, DE-A-25 43 902, DE-A-26 13 005, DE-A-26 45 656, DE-A-28 09 716, DE-A-28 23 159, BE-A-861 241, EP-A-0 004 399, EP-A-0 004 400, DE-A-30 08 588, DE-A-30 14 669, GB-A-80 12 242.

In some embodiments of the recording material according to the invention, the color releasers can be present as oxidizable or couplable color releasers, in others as reducible color releasers. Depending on whether the dye is released from the oxidized or from the reduced form of the color releasing agent, negative or positive illumination is obtained from the original when conventional negative-working silver halide emulsions are used. You can therefore create positive or negative images by selecting suitable color releasing systems. Particularly suitable oxidizable paint releasers are described, for example, in DE-A-26 45 656.

If the color splitter can be oxidized, then it is itself a reducing agent which is oxidized directly or indirectly with the aid of electron transfer agents (electron transfer agent, ETA) through the imagewise exposed silver halide. This creates a pictorial differentiation in terms of the ability to release the diffusible dye. If, on the other hand, the color releaser is reducible, then it is expediently used in combination with a reducing agent present in a limited amount, a so-called electron donor compound or an electron donor precursor compound, which in this case is contained in the coacervate particles of the same packet emulsion in addition to the color releaser. The use of electron transfer agents can also prove to be advantageous in the case of the use of reducible color releasers in combination with electron donor compounds.

In der Formel bedeuten
R¹ _' Alkyl oder Aryl;
R²' Alkyl, Aryl oder eine Gruppierung, die zusammen mit R³' einen ankondensierten Ring vervollständigt; R³' Wasserstoff, Alkyl, Aryl, Hydroxyl, Halogen wie Chlor oder Brom, Amino, Alkylamino, Dialkylamino einschließlich cyclischer Aminogruppen (wie Piperidino, Morpholino), Acylamino, Alkylthio, Alkoxy, Aroxy, Sulfo, oder eine Gruppierung, die zusammen mit R²' einen ankondensierten Ring vervollständigt;
R"' Alkyl;
R5'Alkyl oder vorzugsweise Wasserstoff, ,
und wobei mindestens einer der Reste R¹' bis R," einen Ballastrest enthält.For the production of positive color images of positive originals (original) when using negative working silver halide emulsions, for example, a recording material with a packet emulsion is suitable which contains reducible color releasers of the following formula in combination with an electron donor compound:

Mean in the formula
R ¹ _' alkyl or aryl;
R ² 'is alkyl, aryl or a group which together with R ³ ' completes a fused ring; R ³ 'is hydrogen, alkyl, aryl, hydroxyl, halogen such as chlorine or bromine, amino, alkylamino, dialkylamino including cyclic amino groups (such as piperidino, morpholino), acylamino, alkylthio, alkoxy, aroxy, sulfo, or a group which together with R ² 'completed a condensed ring;
R "'alkyl;
R5'-alkyl or preferably hydrogen,,
and wherein at least one of the radicals R ¹ 'to R, "contains a ballast radical.

The electron donor compound used in combination with a reducible dye releasing agent serves equally as a reducing agent for the silver halide and the color releasing agent. Because the silver halide and the color releaser compete with each other to a certain extent in the oxidation of the electron donor compound, but is superior to the latter, the silver halide present becomes determinant for the image areas within which the color releaser is due to the electron donor compound its reduced form is transferred.

The electron donor compound, which is present in a limited amount, is processed under the conditions of development, e.g. when the imagewise exposed color photographic material is heated, oxidized in accordance with the extent of the exposure and is consequently no longer available for a reaction with the color releaser. This creates an image-like distribution of unused electron donor compound.

Derivatives of hydroquinone, benzisoxazolone, p-aminophenol or ascorbic acid (e.g. ascorbyl palmitate) which have not or only little diffusing have been described as electron donor compounds (DE-A-2 809 716).

Further examples of electron donor compounds are described in DE-A-2 947 425, DE-A-3 006 268, DE-A-3 130 842, DE-A-3 144 037, DE-A-3 217 877, EP-A- 0 124 915 and Research Disclosure No. 24 305 (July 1984). It has been shown that the electron donor compounds mentioned are also suitable for heat-developable recording materials. Particularly suitable are those electron donor compounds which only exist under the conditions of development in the layer of corresponding electron donor compounds which are present in the recording material before development only in a masked form in which they are practically ineffective. Under the conditions of development, the electron donor compounds, which are initially inactive, are then converted into their effective form, for example by hydrolytically cleaving off certain protective groups.

The use of the packet emulsions cured according to the invention makes it possible to assign color formers within the same packet emulsion of a silver halide emulsion to a specific spectral sensitivity to produce a certain partial color image, preferably the partial color image which is complementary to the spectral sensitivity, and to maintain this assignment even if this package emulsion with other packet emulsions of different spectral sensitivity is mixed to form a mixed grain emulsion.

Spatial assignment is understood to mean that the color former is in such a spatial relationship with the silver halide particles that an interaction between them is possible which allows an image-like correspondence between the silver image formed during development and the color image generated from the color former. This is achieved according to the invention in that the color former and the silver halide particles are present side by side in the same coacervate particles.

Spectral assignment is understood to mean that the spectral sensitivity of each of the various packet emulsions and the color of the partial color image generated from the spatially assigned color coupler are in a specific relationship to one another, each of the spectral sensitivities (red, green, blue) having a different color of the relevant partial color image (e.g. teal, purple, yellow) is assigned.

In addition to the constituents already mentioned, the photographic recording material according to the invention can contain further constituents and auxiliary substances. These further constituents or auxiliary substances are preferably contained in the common binder phase of the light-sensitive layer or in one of the other layers. However, they can equally well be part of a complex coacervate hardened according to the invention either alone or in combination with silver halide, color former and / or other auxiliaries.

Such auxiliaries are, for example, auxiliary developers. These auxiliary developers generally have developing properties for exposed silver halide; In the present case, they primarily have a beneficial effect on the reactions which take place between the exposed silver salt (= silver salt in the presence of exposed silver halide) and the reducing agent, the reducing agent being identical to the latter when using oxidizable color releasers, or in this case the use of reducible paint releasers in turn reacts with the paint releasers. Since these reactions consist mainly of electron transfer, the auxiliary developers are also referred to as electron transfer agents (ETA).

Examples of suitable auxiliary developers include hydroquinone, pyrocatechol, pyrogallol, hydroxylamine, ascorbic acid, 1-phenyl-3-pyrazolinone and their derivatives. Since the auxiliary developers have a catalytic function, so to speak, it is not necessary for them to be present in stoichiometric amounts. In general, it is sufficient if they are present in the layer in amounts of up to 1/2 mole per mole of color releaser The layer can be made, for example, from solutions in water-soluble solvents or in the form of aqueous dispersions which have been obtained using oil formers.

Other auxiliaries are, for example, basic substances or compounds which are able to provide basic substances under the influence of the heat treatment. Sodium hydroxide, potassium hydroxide, calcium hydroxide, sodium carbonate, sodium acetate and organic bases, in particular amines such as trialkylamines, hydroxyalkylamines, piperidine, morpholine, dialkylaniline, p-toluidine, 2-picoline, guanidine and their salts, in particular salts with aliphatic carboxylic acids, are to be mentioned here, for example. By providing the basic substances, a suitable medium is created during the heat treatment in the light-sensitive layer and the adjacent layers in order to ensure the release of the diffusible dyes from the paint releasers and their diffusion into the image-receiving layer.

Other auxiliaries are, for example, compounds that can release water under the influence of heat. In particular, inorganic salts containing water of crystallization are suitable for this, for example Na ₂ S0 ₄ .10H20, NH ₄ Fe (S0 ₄ ) ₂ .12H ₂ 0. The water released during heating favors the development and diffusion processes necessary for image formation.

Other auxiliaries are, for example, the so-called thermal solvents, which are generally understood to mean non-hydrolyzable organic compounds which are solid under normal conditions but melt when heated up to the temperature of the heat treatment and thereby provide a liquid medium in which the development processes can take place more quickly. Such thermal solvents can act as diffusion accelerators, for example. Preferred examples of the thermal solvents include polyglycols, such as described in US-A-3,347,675, e.g. Polyethylene glycol with an average molecular weight of 1,500 to 20,000, derivatives of polyethylene oxide such as its oleic acid ester, beeswax, monostearin, compounds with a high dielectric constant, which have an -SO or -CO group, e.g. Acetamide, succinamide, ethyl carbamate, urea, methylsulfonamide, ethylene carbonate, and also polar substances, as described in US Pat. No. 3,667,959, the lactone of 4-hydroxybutanoic acid or 4-hydroxybutyric acid, dimethyl sulfoxide, tetrahydrothiophene-1,1-dioxide and 1,10-decanediol, methyl anisate, biphenyl suberate, etc., as described in Research Disclosure, pages 26 to 28 (December 1976), etc.

To produce a photographic recording material, the packet emulsion cured according to the invention is expediently dispersed in an aqueous solution of a proteinaceous binder and cast into a layer. The layer binder can be hardened in a conventional manner with any hardener such as formaldehyde or a bisfunctional aldehyde, ethyleneimine or vinylsulfonyl compound or with a carboxyl group-activating hardener, such as, for example, a compound of the formula I.

The development of an imagewise exposed color photographic recording material according to the invention based on a chromogenic coupling with diffusion-resistant color couplers takes place, for example, in customary wet processing processes using color developer, bleaching, fixing or. Bleach-fix baths. In the case of color diffusion materials, the development can be effected by using activator pastes or activator baths, as is known from conventional color diffusion photography.

In the case of heat-developable color photographic recording materials, the development process comprises the sub-steps of silver halide development, release of an image-wise distribution of diffusible dyes and diffusion transfer of this image-wise distribution into an image-receiving layer. It is initiated by subjecting the exposed recording material to a heat treatment in which the photosensitive binder layer is heated to an elevated temperature, e.g. is brought in the range of 80 to 250 ° C. This creates suitable conditions in the recording material for the development processes, including dye diffusion, without the addition of a liquid medium, e.g. in the form of a developer bath. During development, dyes which are diffusible in terms of image are released from the dye releasers and transferred to an image-receiving layer which is either an integral part of the color photographic recording material according to the invention or is in contact with it at least during the development period. Image-wise silver development, dye release and color transfer take place synchronously in a one-step development process.

In addition, the color image formation with the color photographic recording material according to the invention can also be carried out in a two-step development process, the silicon shark development and dye release taking place in a first step, followed by the color image transfer in a second step from the photosensitive part to an image receiving part brought into contact with it. e.g. by heating to a temperature between 50 and 150 ° C., preferably to 70 to 90 ° C., in which case diffusion aids (solvents) can be applied externally before the photosensitive part and the image receiving part are laminated.

The image-receiving layer can accordingly be arranged on the same layer support as the light-sensitive element (single sheet material) or on a separate layer support (two-sheet material). It essentially consists of a binder which contains mordants for the determination of the diffusible dyes released from the non-diffusing paint releasers. Long-chain quaternary ammonium or phosphonium compounds, e.g. those as described in US-A-3,271,147 and US-A-3,271,148.

Certain metal salts and their hydroxides, which form poorly soluble compounds with the acid dyes, can also be used. Also to be mentioned here are polymeric mordants, such as those described in DE-A-2 315 304, DE-A-2 631 521 or DE-A-2 941 818. The dye mordants are dispersed in the mordant layer in one of the usual hydrophilic binders e.g. in gelatin, polyvinylpyrrolidone, completely or partially hydrolyzed cellulose esters. Of course, some binders can also act as mordants, e.g. Polymers of nitrogen-containing, optionally quaternary bases, such as, for example, of N-methyl-4-vinylpyridine, 4-vinylpyridine, 1-vinylimidazole, as described, for example, in US Pat. No. 2,484,430. Further usable binding agents are, for example, guanyl hydrazone derivatives of alkyl vinyl ketone polymers, such as described, for example, in US Pat. No. 2,882,156, or guanylhydrazone derivatives of acylstyrene polymers, as described, for example, in DE-A-2 009 498. In general, however, other binders, eg Add gelatin.

If the image-receiving layer remains in layer contact with the light-sensitive element even after development is complete, there is usually an alkali-permeable, pigment-containing, light-reflecting binder layer between them, which serves for the optical separation between negative and positive and as an aesthetically pleasing background for the transferred positive color image. In this case, the yellow filter layer used according to the present invention is on the side of the light-sensitive layer which lies opposite the pigment-containing light-reflecting binder layer. If the image-receiving layer is arranged between the support and the photosensitive element and is separated from the latter by a pre-formed light-reflecting layer, either the support must be transparent so that the color transfer image produced can be viewed through it, or the photosensitive element together with the light-reflecting layer of the image-receiving layer are removed to expose the latter. However, the image-receiving layer can also be present as the uppermost layer in an integral color photographic recording material, in which case the exposure is expediently carried out by means of transparent layer supports.

example a) Silver halide emulsion

A silver halide emulsion was used which contained 98.3 g of AgNO ₃ and 98.3 g of gelatin per kg of silver chloride bromide (20 mol% chloride; mean grain diameter 0.36 µm ₎ . The emulsion was spectrally sensitized per 1 g of AgNO ₃ with 0.7 mg each of the oxacarbocyanine dyes of the following two formulas:

b) coupler dispersate

62.9 g of 1- (2,4,6-trichlorophenyl) -3- (2-chloro-5-tetradecanoylamidoanilino) -5-pyrazolone were dissolved in 62.9 g of tricresyl phosphate and 150 ml of ethyl acetate in the presence of 2 g of wetting agent (Erkantol @ 20) dispersed in a solution of 27.6 g gelatin and 1.7 g phenol in 500 ml water. The auxiliary solvent was then removed using relaxed steam. Yield: 740 g.

c) General instructions for the preparation of the test package emulsions

88.90 g of the silver halide emulsion described under a) are melted in 120 g of water at 40 ° C., then 74.0 g of the coupler dispersate described under b) are added and melted. Then it is diluted with 100 ml of water and a solution of 2.3 g of gum arabic in 112.7 g of water is slowly added and the mixture is diluted again with 100 ml of water. The pH should be between 5.0 and 5.1, not below 5.0. Now you have to change from normal magnetic stirring (slow) to efficient stirring (paddle stirrer with at least 2,000 rpm or mixing siren (homogenizer). A microscope sample must not show any coacervation!

Now it is slowly adjusted to pH = 4.4 to 4.5 at 40 ° C with 1% acetic acid and the coacervation is monitored using a microscope sample (control).

• 1) Härtung
• 2) Zentrifugieren und Konditionieren.

The mixture is then cooled to 8 to 10 ° C. while stirring. The following treatment steps follow:

• 1) hardening
• 2) Centrifuge and condition.

d) packet emulsions Package emulsion A: (not according to the invention, comparison)

• Nach Abkühlung auf 8 bis 10°C wurden 2,20 g Chromalaun, gelöst in 640 ml Wasser, innerhalb 10 min zugetropft und noch 1 h nachgerührt (2.000 Upm). Dann wurde durch Zentrifugieren aufkonzentriert, einmal mit 400 ml Waser gewaschen und erneut zentrifugiert. Das Zentrifugat (230 g) wurde frisch mit 10 g 20 %iger Gelatine, 4 ml Triton@ X 100 (4 %ige wäßrige Lösung) und 56 g Wasser auf 300 g konditioniert und kurz homogenisiert.

Production as indicated under c) with the following further treatment:

• After cooling to 8 to 10 ° C., 2.20 g of chrome alum, dissolved in 640 ml of water, were added dropwise within 10 minutes and the mixture was stirred for a further 1 hour (2,000 rpm). It was then concentrated by centrifugation, washed once with 400 ml of water and centrifuged again. The centrifugate (230 g) was freshly conditioned to 300 g with 10 g of 20% gelatin, 4 ml of Triton @ X 100 (4% aqueous solution) and 56 g of water and briefly homogenized.

Package emulsion B: (not according to the invention, comparison)

Preparation as packet emulsion A, but after the addition of chromium alum and 1 h stirring time (= hardening time), 11.5 ml of a 10% strength aqueous solution of the compound H-15 diluted with 60 ml of water were added dropwise over the course of 2 min and the mixture was subsequently stirred for 1 h . Further procedure as for packet emulsion A.
Centrifugate: 185 g, conditioned: 300 g.

Package emulsion C: (according to the invention)

• Nach Abkühlung auf 8 bis 10°C wurden 11,5 ml 10 %ige wäßrige Lösung der Verbindung H-15 verdünnt in 100 ml Wasser innerhalb von 4 bis 5 min zugetropft und 1 h nachgerührt und weiter wie bei Paketemulsion B verfahren. Das Zentrifugat (105 g) wurde frisch mit 10 g 20 %iger Gelatine, 4 ml 4 %ige wäßriger Triton@ X 100-Lösung und 81 ml Wasser auf 200 g Endgewicht konditioniert und homogenisiert.

Production as indicated under c) with the following further treatment:

• After cooling to 8 to 10 ° C., 11.5 ml of 10% strength aqueous solution of the compound H-15, diluted in 100 ml of water, were added dropwise over the course of 4 to 5 minutes and the mixture was stirred for 1 hour and proceeded as in package emulsion B. The centrifugate (105 g) was freshly conditioned with 10 g of 20% gelatin, 4 ml of 4% aqueous Triton @ X 100 solution and 81 ml of water to a final weight of 200 g and homogenized.

Packet emulsion D: (not according to the invention, comparison)

• Nach Abkühlung auf 8 bis 10°C wurden 200 mg des Härtungsmittels Bisvinylsulfonylmethan, gelöst in 20 ml Wasser/Aceton-Mischung (50:50) und verdünnt mit 80 ml Wasser, innerhalb von 4 bis 5 min zugetropft und 1 h nachgerührt und weiter wie bei Paketemulsion C verfahren.
• Das Zentrifugat (147 g) wurde frisch mit 10 g 20 %iger Gelatine, 4 ml 4 %iger wäßriger Triton@ X 100-Lösung und 39 g Wasser auf 200 g konditioniert und kurz homogenisiert.

Production as indicated under c) with the following further treatment:

• After cooling to 8 to 10 ° C., 200 mg of the hardening agent bisvinylsulfonylmethane, dissolved in 20 ml of water / acetone mixture (50:50) and diluted with 80 ml of water, were added dropwise over the course of 4 to 5 minutes and the mixture was stirred for 1 hour and further as proceed with packet emulsion C.
• The centrifugate (147 g) was freshly conditioned to 200 g with 10 g of 20% gelatin, 4 ml of 4% aqueous Triton @ X 100 solution and 39 g of water and briefly homogenized.

Packet emulsion E: (not according to the invention, comparison)

• Nach Abkühlung auf 8 bis 10°C wurden 500 mg des Härtungsmittels der folgenden Formel
  
  gelöst in 20 ml Wasser/Aceton-Mischung (50:50) und verdünnt mit 80 ml Wasser, innerhalb von 4 bis 5 min zugetropft und 1 h nachgerührt und weiter wie bei Paketemulsion D verfahren. Das Zentrifugat (168 g) wurde frisch mit 10 g 20 %iger Gelatine, 4 ml Triton@ X 100-Lösung und 18 g Wasser auf 200 g konditioniert und kurz homogenisiert.

Production as indicated under c) with the following further treatment:

• After cooling to 8 to 10 ° C, 500 mg of the curing agent of the following formula
  
  dissolved in 20 ml water / acetone mixture (50:50) and diluted with 80 ml water, added dropwise within 4 to 5 min and stirred for 1 h and proceed as for package emulsion D. The centrifugate (168 g) was freshly conditioned with 10 g of 20% gelatin, 4 ml of Triton @ X 100 solution and 18 g of water to 200 g and briefly homogenized.

e) Photographic recording materials with packet emulsions (general rule)

• Probe P1: Mit 110,7 g Paketemulsion A und 181 g Wasser,
• Probe P2: mit 110,7 g Paketemulsion B und 181 g Wasser,
• Probe P3: mit 73,8 g Paketemulsion C und 218,7 g Wasser,
• Probe P4: wie Probe P3, jedoch mit 73,8 g Paketemulsion D,
• Probe P5: wie Probe P3, jedoch mit 73,8 g Paketemulsion E.

6 ml Triton @ X 100 (4% aqueous solution) and 21.5 g 20% gelatin are added to a certain amount of the respective package emulsion at 40 ° C. and the mixture is made up to 320 g final weight with water. The casting solution thus obtained is applied to a transparent layer of polyethylene terephthalate with a wet layer thickness of 50 μm and dried. In a covering layer of a 3% _strength; 30 µm wet application gelatin and finally a 60 µm wet application hardening layer (1% gelatin solution) containing a hardener. After curing and drying, the following samples 1 to 5 are obtained with packet emulsions A to E.

• Sample P1: With 110.7 g packet emulsion A and 181 g water,
• Sample P2: with 110.7 g packet emulsion B and 181 g water,
• Sample P3: with 73.8 g package emulsion C and 218.7 g water,
• Sample P4: as sample P3, but with 73.8 g packet emulsion D,
• Sample P5: as sample P3, but with 73.8 g packet emulsion E.

f) Comparative materials (without package emulsions)

Sample P6: 32.8 g of the silver halide emulsion described under a) were melted at 40 ° C. and 8 ml of a 4% strength aqueous solution of Triton @ X 100 were added. Then 27.3 g of the coupler dispersate described under b) were added and melted, further 0.85 g of gum arabic, dissolved in 41.6 g of water, and 21.5 g of 20% strength gelatin were added, and 229.6 g of water to 320 g final weight. The casting solution obtained in this way was coated on a polyethylene terephthalate support as indicated under e), covered with a top layer and cured.

Sample P7: Production like sample P6, but without the addition of gum arabic.

g) exposure, processing, evaluation

Samples 1 to 7 were placed in a sensitometer (color temperature 2,850 K; 19,000 Ix) without a gray filter for 1/50 s behind a wedge
observed and processed according to the color negative development processes described in The British Journal of Photography, 1974, pages 597 and 598.

Subsequently, RMS granularity measurements were carried out on the processed samples (cf. JAMES, The Theory of the Photographic Process, fourth edition, Macmillan Publishing Co., Inc. New York, pages 619 and 620). The results are illustrated in FIG. 1. The packet emulsion cured according to the invention gives the most favorable RMS granularity values (curve 3). However, the granularity values shown in curves 6 and 7 of samples 6 and 7 containing no packet emulsion (conventional layers) are even more favorable; however, they cannot be used to produce single-layer multicolor recording materials.

Claims (4)

1. Photographic recording material with at least one binder layer and a dispersion of hardened particles of a complex coacervate contained therein, characterized in that the particles of the complex coacervate contain at least one proteinaceous polymeric binder containing carboxyl groups and amino groups and are hardened with a hardening agent of the following formula 1

in which mean: R ¹ and R ² individually the same or different, in each case an alkyl group with 1 to 8 carbon atoms or an aryl or aralkyl group optionally substituted with an alkyl group with 1 or 2 carbon atoms or with a halogen atom, or together to complete an optionally with an alkyl group with 1 or 2 carbon atoms or heterocyclic ring substituted with a halogen atom, for example a piperidine or morpholine ring, R ^{3 represents} a hydrogen atom or an alkyl group with 1 or 2 carbon atoms, n 0 or 2. 2. Recording material according to claim 1, characterized in that the particles of the complex coacervate have an average particle size in the range from 0.5 to 20 µm. 3. Recording material according to claim 1, characterized in that the particles of the complex coacervate contain at least one photographically active or useful compound. 4. Recording material according to claim 3, characterized in that the particles of the complex coacervate contain light-sensitive silver halide and at least one color former.

Images