EP0078959A1 - Colour-photographic recording material with non-diffusing electron donor precursor compounds - Google Patents

Abstract

Compounds of the formula <IMAGE> wherein R¹ is an aromatic group; and R² is H, alkyl, alkenyl, aryl or acyl, are suitable ED precursor compounds for use in color photographic materials. They are preferably used in combination with reducible paint releasing agents. They are also suitable as so-called scavengers.

Description

The invention relates to a color photographic recording material having at least one light-sensitive silver halide emulsion layer which contains non-diffusing electron donor precursor compounds from which strong reducing agents are formed under the conditions of alkaline development. In particular, the invention relates to a recording material in which the electron donor precursor compounds mentioned are used in combination with non-diffusing reducible coloring compounds which, in the reduced state under the conditions of alkaline development, release diffusible dyes, which as such or after conversion into their metal complexes for image formation serve.

DE-OS 2 809 716 describes coloring compounds with an electron-accepting nucleophilic precursor group, which in the reduced state are subject to an intramolecular nucleophilic displacement reaction under the conditions of alkaline development with the release of a diffusible dye.

The reduction is brought about by what are known as electron donor compounds (ED compounds), which are present in the layers in addition to the coloring compounds and which are oxidatively imagewise oxidized during development and thus consumed.

The remaining imagewise distribution (positive residual image) of the ED compounds reacts with the coloring compound and triggers the imagewise release of diffusible dyes. The ED compounds described there are, for example, derivatives of benzisoxazolone, hydroquinone, p-aminophenol and ascorbic acid. In order to enable the generation of high-quality images by the process described in DE-OS 2 809 716, the ED compounds must not only be able to be oxidized by exposed silver halide or by silver halide developer oxidation products, but must also be able to use the coloring compounds themselves to reduce. In addition, the respective rates of the oxidation or reduction reaction must be optimally adjusted to one another in such a way that the ED compound is already oxidized to a remarkable extent in the course of development before it in turn can reduce the coloring compound. The known ED connections do not meet all of these requirements. Regarding what is expressed, for example, in an insufficient color density and / or in an unacceptable color haze of the color transfer images produced.

The high reduction capacity of suitable ED compounds also results in a high sensitivity to oxidation, which is manifested in premature, non-imagewise consumption of the ED compounds by oxidation and thereby deteriorated image properties of the transfer image, which particularly consist in an insufficient color density, when the photographic recording material is stored for a long time. From DE-OS 2 809 716 it is also known to use ED compounds not as such, but in the form of a less oxidation-sensitive precursor compound, from which the actual ED compound is only formed under the conditions of alkaline development. Examples of this are the ED connections ED-8, ED-9 and ED-10 of the aforementioned German published application. With the known ED precursor compounds, however, only an inadequate density of the color transfer image is obtained within an acceptable development time, which may be due to the fact that the actual ED compound either does not form quickly enough from its precursor compound or has an insufficient reduction capacity. Research Disclosure 19429 (June 1980) describes ED precursor compounds which are derived from d-hydroxyketones and which carry an electron-withdrawing group Z on the α-carbon atom.

The invention has for its object to provide new oxidation-stable ED precursor compounds that contribute to a good storage stability of the photographic material exhibit elevated temperature and / or humidity and from which ED compounds with a high reduction capacity are only formed under the conditions of alkaline development. In particular in the color diffusion transfer process, they are intended to enable the generation of color transfer images with improved color density if they are used in combination with non-diffusing, reducible coloring compounds.

worin bedeuten:

• R eine carbocyclische oder heterocyclische aromatische Gruppe; und
• _R ² Wasserstoff, Alkyl, Alkenyl, Aryl oder Acyl;

wobei wenigstens einer der Reste R und R² einen Ballastrest enthält.The invention relates to a color photographic recording material with at least one light-sensitive silver halide emulsion layer and an associated non-diffusing coloring compound, which contains in at least one light-sensitive silver halide emulsion layer or a non-light-sensitive binder layer a non-diffusing electron donor precursor compound (ED precursor compound) from which one does not exist under alkaline development conditions diffusing ED compound is formed, characterized in that the ED precursor compound corresponds to the following formula I:

in which mean:

• R is a carbocyclic or heterocyclic aromatic group; and
• _R ^{2 is} hydrogen, alkyl, alkenyl, aryl or acyl;

wherein at least one of the radicals R and R ² contains a ballast radical.

The ED precursor compounds according to the invention are suitable for use in color photographic recording materials wherever it is a question of introducing strong reducing agents into the layers in a capped form, be it as a capped developing agent for silver halide or as a capped reducing agent to prevent the undesired diffusion of oxidation products, resulting from the development of silver halide. It is irrelevant what kind of coloring compounds are used for color image generation. These can be color couplers or coloring compounds that release diffusible dyes as a result of the development (color releasers). However, the preferred use of the ED precursor compounds according to the invention can be seen in the combination with non-diffusing, reducible coloring compounds which, in reduced form, release diffusible dyes under the conditions of alkaline development.

A preferred object of the invention is therefore a color photographic recording material with at least one light-sensitive silver halide emulsion layer and a combination of a non-diffusing, reducible coloring compound which is capable of releasing a diffusible dye in the reduced state under the alkaline development conditions, and a non-diffusing electron donor precursor compound ( ED precursor compound), from which a non-diffusing electron donor compound (ED compound) is formed under the alkaline development conditions, which is able to reduce the non-diffusing coloring compound under the alkaline development conditions, characterized in that the recording material is a compound of the ED precursor compound contains general formula I.

The aromatic group represented by R ¹ in formula I can be a carbocyclic group, for example a phenyl, naphthyl or anthracenyl group or a 5- or 6-membered heterocyclic group with at least one of the heteroatoms N, 0, S as a ring member, for example one Furyl, thienyl, pyrryl or pyridyl group. The carbocyclic and heterocyclic aromatic groups can be unsubstituted or mono- or polysubstituted and contain fused carbocyclic or heterocyclic rings, which in this case need not be aromatic.

The aryl group represented by R ² in formula I is in particular a phenyl group, which can also be mono- or polysubstituted.

The acyl group represented by R ² in formula I is derived from aliphatic or aromatic carboxylic acids of the formula R-COOH, in which R represents alkyl, alkenyl, aryl or a heterocyclic group, or is, for example, a carbamoyl radical.

Examples of suitable substituents on the aromatic groups represented by R and on the aryl group represented by R are: halogen such as fluorine, chlorine, bromine or iodine, hydroxy, sulfo, sulfamoyl, trifluoromethyl, trifluoromethylsulfonyl, amino, nitro, cyano, carboxy, carbamoyl , Alkoxycarbonyl, alkyl, alkenyl, cycloalkyl, in particular cyclohexyl or cyclopentyl, aryl, in particular phenyl, or heterocyclic groups, where the last-mentioned groups (alkyl, alkenyl, cycloalkyl, aryl and heterocyclic groups) can contain further substituents, for example those of the aforementioned Type and wherein said alkyl, alkenyl, cycloalkyl, aryl or heterocyclic groups ent-. are not connected directly or via one of the following divalent connecting links: -O-, -S-, -SO ₂ -, -S0 ₂ -NR-, -NR-S0 ₂ -, -CO-, -NR-CO-, - CO-NR-, -NR-COO-, -O-CO-NR-, -NR-CO-NR- (R = hydrogen or alkyl).

The alkyl or alkenyl groups represented by R ² or present as substituents in R and R can be straight or branched and contain 1-22 C atoms, and can also be further substituted, for example by halogen (such as fluorine, chlorine or bromine), hydroxy , Amino, alkoxy, aroxy, alkylthio, arylthio, a heterocyclic thioether group, alkylsulfonyl, arylsulfonyl or a heterocyclic group, such as a 5- or 6-membered heterocyclic ring linked via a ring nitrogen atom.

In preferred embodiments of the invention, _R ¹ is an optionally substituted phenyl group and R ² is, in preferred embodiments, an alkyl radical having 1 to 3 C atoms, which may optionally be substituted by halogen, alkoxy, aroxy or hydroxyl.

According to the invention, all of the substituents present in the ED precursor compound are such that the ED precursor compound cannot be diffusively incorporated into photographic layers. For this purpose, for example, at least one of the substituents present, for example at least one of the radicals _R ¹ and R, contains a ballast radical. The radical R ¹ is preferably such that even after the acyl radical -COR ^{2 has} been split off under the influence of alkali, the residual molecule remains diffusion-resistant or has only a limited diffusibility. A diffusion-resistant incorporation of the ED precursor compound is particularly desirable because these compounds have an exact localization in a specific layer or be used in a certain quantity relation to assigned non-diffusing, reducible coloring compounds, which should not change significantly even if the photographic recording material is stored for a long time.

Such residues are to be regarded as ballast residues, which make it possible to incorporate the compounds 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 22 C atoms and optionally also carbocyclic or heterocyclic aromatic groups are preferably suitable for this purpose. With the remaining part of the molecule, these residues are either direct or indirect, for example. connected via one of the following groups; -NHCO-, -NHS0 ₂ - _' -NR-, where R is hydrogen or alkyl, -O- or -S-. In addition, the diffusion-proofing radical can also contain water-solubilizing groups, such as sulfo groups or carboxyl groups, which in certain cases can also be present in anionic form. Since the diffusion properties depend on the molecular size of the total compound used, it is sufficient as ballast residues in certain cases, for example if the total molecule used is large enough or if the ED precursor compounds are incorporated into the layers using so-called oil-forming agents or high-boiling coupler solvents in emulsified form shorter chain residues, for example isoamyl or tert-butyl residues, can also be used.

Bei den erfindungsgemäßen ED-Verbindungen handelt es sich um α-substituierte Malonsäurediamide. Zu ihrer Herstellung geht man zweckmäßigerweise aus von aromatischen Aminen der Formel R^1-NH₂, die mit Diethylmalonat unter Freisetzung von Ethanol kondensiert werden. Aus dem erhaltenen Malonsäurediamid wird nach bekannten Methoden die α-Brom-Verbindung hergestellt. Anschließend wird das Bromatom gegen den Rest -O-C_O-_R ² ausgetauscht. Im folgenden wird das Herstellungsverfahren am Beispiel der Verbindung 2 erläutert.Some examples of the non-diffusing ED precursor compounds used according to the invention are listed below:

The ED compounds according to the invention are α-substituted malonic acid diamides. For their preparation, it is expedient to start from aromatic amines of the formula R ¹ -NH ₂ , which are condensed with diethyl malonate with the liberation of ethanol. The α-bromo compound is prepared from the malonic acid diamide obtained by known methods. The bromine atom is then exchanged for the rest -OC _O - _R ² . The production process is explained below using the example of compound 2.

Establishing connection 2

• a) 15.1 g of 3-amino-4-methylbenzoic acid in 150 ml of dimethylformamide were mixed with 13.8 g of potassium carbonate and 30.5 g of hexadecyl bromide and heated with stirring on the boiling water bath for 2 hours. After cooling to room temperature, the reaction mixture was stirred in a mixture of 300 ml of methanol and 30 ml of water. The resulting precipitate was filtered off with suction and stirred in succession in 200 ml of water and 300 ml of methanol, suctioned off again and air-dried. Yield: 29 g.
• b) 30 g of the compound obtained and 6.4 g of diethyl malonate were gradually heated to 220 ° C. while distilling off the ethanol which had been split off and kept at this temperature for 2 h. The reaction mixture was stirred with 50 ml of methanol and suction filtered. After stirring again with 50 ml of cyclohexane, 11 g of malonic anilide were obtained.
• c) 6.5 g of the compound obtained under b) were mixed with 0.41 ml of bromine in a suspension in 50 ml of glacial acetic acid. The mixture was 15 min. heated to 60 ° C. After cooling to room temperature and adding 50 ml of methanol, the precipitate formed was suction filtered and washed with methanol. Yield: 5.8 g.

Connection 2

2.4 g of ethoxyacetic acid and 2.1 g of potassium carbonate were successively added to 13.5 g of the compound obtained under c) in 120 ml of dimethylacetamide, and the reaction mixture was stirred at room temperature for 3 h. The reaction mixture was then poured into a mixture of 300 ml of methanol, 30 ml of water and 10 ml of glacial acetic acid at 10 ° C. The resulting precipitate was filtered off with suction and stirred in succession with 200 ml of water and 200 ml of methanol, filtered off with suction, washed with 50 ml of methanol and dried in air.

Yield: 11 g.

The ED precursor compounds according to the invention are the known ED compounds, e.g. Ascorbyl palmitate, as well as the known ED precursor compounds, are superior in that they can be used to produce higher maximum color densities with lower minimum color densities (veils) within a given development time. It remains to be seen whether the higher maximum color densities obtained can be attributed to a slight cleavage (hydrolysis) of the acyl residue and thus to a faster availability of the actual ED compounds or to their higher reducibility or both.

Another advantage of the ED precursor compounds according to the invention is that they are oxidized insensitive form and are only converted to the actual ED compounds during development by treatment with aqueous alkali (hydrolytic cleavage of the acyl group).

worin bedeuten

• R Alkyl oder Aryl;
• _R ² Alkyl, Aryl oder eine Gruppierung, die zusammen mit R³ einen ankondensierten Ring vervollstän- ,digt;
• R³ Wasserstoff, Alkyl, Aryl, Hydroxyl, Halogen wie Chlor oder Brom, Amino, Alkylamino, Dialkylamino einschließlich cyclischer Aminogruppen (wie _Pipe- ridino, Morpholino), Acylamino, Alkylthio, Alkoxy, _Aroxy, Sulfo, oder eine Gruppierung, die zusammen mit _R ² einen ankondensierten Ring vervollständigt;
• _R ⁴ Alkyl;
• R⁵ Alkyl oder vorzugsweise Wasserstoff;
• A den Rest eines diffusionsfähigen Farbstoffes oder Farbstoffvorläufers;
• _X ein bivalentes Bindeglied der Formel -R-(^L) P-^(R) _q-, worin R einen Alkylenrest mit 1 - 6 C-Atomen oder einen gegebenenfalls substituierten Arylen- oder Aralkylenrest bedeutet und wobei die beiden Reste R die gleiche Bedeutung oder voneinander verschiedene Bedeutungen haben können;
• L -O-, -CO-, -CONR^6-, -SO₂NR⁶-, -O-_CO-_NR ^6-, -_S-, -SO- oder -SO₂- (R₆ = Wasserstoff oder Alkyl);
• p 0 oder 1;
• q 0 oder 1;
• m 0 oder 1,

und wobei mindestens einer der Reste R¹, _R ², _R ³ und _R ⁴ einen Ballastrest enthält.The reducible color releasers used in combination with the ED precursor compounds according to the invention release a diffusible dye under alkaline development conditions by reduction or as a result of a reduction. Reducible color releasers are described in DE-OS 2 809 716, in DE-OS 3 008 588, DE-OS 30 14 669, in EP-A 0 004 399 and in GB-A 80 12 242. Corresponding reducible color releasers used according to the invention correspond of the following formula II:

in what mean

• R is 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 _P IPE ridino, morpholino), acylamino, alkylthio, alkoxy, _A roxy, sulfo, or a group which completes, together with _R ² form a fused ring;
• _R ⁴ alkyl;
• R ^{5 is} alkyl or preferably hydrogen;
• A the rest of a diffusible dye or dye precursor;
• _{X is} a bivalent link of the formula -R- ( ^L ) P- ^(R) _q -, in which R is an alkylene radical having 1-6 C atoms or an optionally substituted arylene or aralkylene radical and where the two radicals R have the same meaning or can have different meanings from each other;
• L -O-, -CO-, -CONR ^6- , -SO ₂ NR ⁶ -, -O- _C O- _NR ^6- , - _S -, -SO- or -SO ₂ - (R ₆ = hydrogen or alkyl );
• p 0 or 1;
• q 0 or 1;
• m 0 or 1,

and wherein at least one of the radicals R ¹ , _R ² , _R ³ and _R ⁴ contains a ballast radical.

The represented in formula II by R ¹ , R ² , _R ³ and R ⁵ Alkyl radicals can be straight-chain or branched and generally contain up to 18 carbon atoms. Examples are methyl, n-propyl, tert-butyl, tetradecyl, octadecyl. The aryl radicals represented by the radicals _R ¹ , _R ² and _R ^{3 mentioned} are, for example, phenyl groups which can be substituted, for example by long-chain alkoxy groups.

In an acylamino radical represented by _R ³ , the acyl group is derived from aliphatic or aromatic carboxylic or sulfonic acids. The fused-on rings completed by R and R ³ are preferably carbocyclic rings, for example fused-on benzene or bicyclo [2,2,1] heptene rings.

An alkyl radical represented by R ⁴ can be straight-chain or branched, substituted or unsubstituted and contain up to 21 C atoms. Examples are methyl, nitromethyl, phenylmethyl (benzyl), heptyl, tridecyl; Pentadecyl, heptadecyl, -C ₂₁ H ₄₃ .

Preferred embodiments of the color releasers used according to the invention are those in which _R ¹ , _R ² and R ³ together contain in a quinoid carrier radical not more than 8, in particular not more than 5, carbon atoms, and R 4 is an alkyl radical with at least 11 carbon atoms represents.

Preferred embodiments are also those in which R ^{1 is} an alkoxyphenyl radical with at least 12 C atoms in the alkoxy group and _R ² , _R ³ , _R ⁴ together contain no more than 8 C atoms.

worin _R , _R ², R³, R⁴, R die bereits angegebenen Bedeutungen haben.The preferably used reducible dye releasers contain, per dye residue A, a diffusion-releasable quinoid carrier residue of the formula

wherein _R , _R ² , R ³ , R ⁴ , R have the meanings already given.

In principle, the residues of dyes of all classes of dyes are suitable as dye residues insofar as they are sufficiently diffusible to be able to diffuse through the layers of the light-sensitive material into the 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 carrier residue containing ballast groups sult. Of dyes that are particularly suitable for the novel process, should be mentioned: azo dyes, azomethine, _A nthra- chino dyes, phthalocyanine dyes, indigoid dyes, triphenylmethane dyes, including dyes, which complexes with metal ions or complexable.

The residues of dye precursors are to be understood as the residues of those compounds which, in the course of photographic processing, are subject to customary or additional processing steps, either by oxidation, by coupling, by complex formation or by exposure of an auxochromic group in a chromophoric system, for example by Saponification to 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 of essential importance, the latter are also to be understood below under the term dye residues.

In a preferred embodiment of the present invention, the color photographic recording material in monochromatic processes contains at least one, in processes for producing multicolored images usually at least three image-forming layer units, each of which has at least one light-sensitive silver halide emulsion layer and one contains the associated combination of a non-diffusing, reducible coloring compound and an electro-donor compound, an ED precursor compound according to the invention being used in at least one layer unit. As a rule, one of the layer units is predominantly sensitive to blue light, another one to green light and a third one to red light, the assigned coloring compounds each providing complement-colored image dyes.

"Assignment" and "assigned" is understood to mean that the mutual arrangement of silver halide emulsions, ED compound or ED precursor compound and color releaser is of such a kind that an interaction between them is possible which results in an imaginary correspondence between the formed silver image and allows the consumption of ED compound on the one hand and between the unused ED compound and paint releaser on the other hand, so that an imagewise distribution of diffusible dye is produced in accordance with the non-nickel silver halide. For this purpose, light-sensitive silver halide and a combination of color releaser and ED compound need not necessarily be present in the same layer; they can also be accommodated in mutually adjacent layers, each belonging to the same layer unit.

A sufficient interaction between the color To ensure splitter and the associated ED precursor compound, it is advisable to place these two compounds in a combination in the same layer, which does not, however, have to be identical to the assigned silver halide emulsion layer. The fact that the ED precursor compounds according to the invention are hydrolysis-stable under neutral conditions and thus also insensitive to oxidation makes these compounds particularly suitable for use in a common emulsifier (together with the color releaser), whereas conventional ED compounds are too sensitive to oxidation under comparable conditions have, so that they can not be used with the paint releasers in the same emulsifier.

All methods are suitable for incorporating the ED precursor compounds according to the invention by which hydrophobic compounds are usually incorporated into photographic layers, i.e. the usual emulsification techniques come into question, e.g. Methods by which photographic auxiliaries are added to the casting solutions in the form of emulsifiers using so-called oil formers. It is advisable to avoid all methods in which the use of alkali is unavoidable.

The reducible color releaser is generally used in a layer in an amount sufficient to produce a color image with the highest possible maxi to produce painterly color density, for example in an amount of 1 - 20 10 ^-4 mol / m ^2. The amount of the ED precursor compound according to the invention is matched to that of the paint releasing agent. It should be large enough to achieve the highest possible maximum color density, ie in order to be able to reduce the color splitting as completely as possible. On the other hand, it should not be significantly higher than is necessary for this, so that the resulting reducing agent at the exposed areas can be used as completely as possible through the development of the exposed silver halide. The best in a particular case quantity ratios between silver halide, ED-precursor compound and _F arbabspalter be determined appropriately based on routine experiments. Useful results can be obtained, for example, if the ED precursor compound is present in each case in a 0.5-5 times molar amount, based on the color releasing agent. The suitable quantitative ratio between silver halide and assigned color releaser is approximately in the range of 2 to 20 moles of silver halide per mole of color releaser.

Separating layers are expediently present between different layer units, which can contain compounds which react with diffusing development products and are able to prevent their diffusion from one layer unit into another. This helps to ensure that the assignment is always limited to one shift unit. Such connections are known, for example they are not suitable diffusing hydroquinone derivatives and, for example, the "scavenger compounds" described in the publication "Research Disclosure No. 17 842" (February 1979). Last but not least, the ED precursor compounds according to the invention can also perform this function, regardless of the type of coloring compound used (color coupler, color releaser), if the ED precursor compounds according to the invention are incorporated as so-called scavengers in a separating layer between different layer units.

The interaction between the exposed silver halide and the ED compound is generally accomplished by the oxidized form of the silver halide developer used. The latter is oxidized imagewise during development and the oxidation product is in turn able to oxidize the ED compound and thus to avoid the reaction with the color releaser.

Examples of suitable silver halide developing agents are hydroquinone and its derivatives, pyrocatechol and its derivatives, p-phenylenediamine derivatives and 3-pyrazolidone compounds, in particular 1-phenyl-3-pyrazolidone, 1-phenyl-4,4-dimethyl-3-pyrazolidone, 4 Hydroxymethyl-4-methyl-1-phenyl-3-pyrazolidone, 1-phenyl-4-methyl-3-pyrazolidone, 1-phenyl-5-methyl-3-pyrazolidone, 1-phenyl-4,4-bis- ( hydroxymethyl) -3-pyrazolidone, 1,4-dimethyl-3-pyrazolidone, 4-methyl-3-pyrazolidone, 4,4-dimethyl-3-pyrazolidone, 1- (3-chlorophenyl) -4-methyl-3- pyrazolidone, 1- (4-chlorophenyl) -4-methyl-3-pyrazolidone, 1- (3-chlorophenyl) .- 3-pyrazolidone, 1- (4-chlorophenyl) -3-pyrazolidone, 1- (4-tolyl) -4-methyl-3-pyrazolidone, 1- (4-tolyl) -4-hydroxymethyl-4-methyl-3-pyrazolidone, 1- (3-tolyl) -3-pyrazolidone, 1- (3-tolyl) -4 , 4-dimethyl-3-pyrazolidone, 1- (2-trifluoroethyl) -4,4-dimethyl-3-pyrazolidone and 5-methyl-3-pyrazolidone, including those derivatives of 3-pyrazolidone that are in capped form, for example acetylated phenidone derivatives.

A combination of different silver halide developing agents can also be used. The silver halide developing agents can be contained in an alkaline developer preparation or also in whole or in part in one or more layers of the color photographic recording material to be processed.

In order to carry out the color diffusion transfer method according to the present invention, a light-sensitive element is generally used which contains one or more silver halide emulsion layer units and the reducible color releasers and ED compounds or their precursors associated therewith, and an image receiving element in which, by the image transfer, the released ones Dyes the desired color image is generated. For this purpose, it is necessary that between the photosensitive element and the image receiving element at least for a finite period of time within the development time there is firm contact so that the imagewise distribution of diffusing dyes produced in the photosensitive element as a result of development can be transferred to the image receiving element. The contact can be made after development has started or it can have been made before development begins. The latter is the case, for example, if a so-called integral recording material is used to carry out the color diffusion transfer process, in which the light-sensitive element and the image-receiving element form an integral unit, also referred to below as mono-sheet material, which can continue to exist even after the development process has ended, if a separation of the photosensitive element from the image receiving element is not provided even after color transfer. Such an embodiment is described for example in DE-OS 2 019 430.

The image-receiving element can accordingly be a component of the color photographic recording material, for example in the form of an image-receiving layer which is arranged below the light-sensitive element on a transparent support, with an opaque, preferably light-reflecting, binder layer advantageously being located between the image-receiving layer and the light-sensitive element. The image receiving layer used in another embodiment of the color transfer process but also another configuration of the ink transfer process but can also be arranged on a separate carrier (image-receiving sheet), typically includes in known manner a basic mordant for diffusing anionic (acidic) _F ARB materials.

Long-chain quaternary ammonium or phosphonium compounds or tertiary sulfonium compounds, e.g. those as described in US Pat. Nos. 3,271,147 and 3,271,148. Furthermore, certain metal salts and their hydroxides which form compounds which are sparingly soluble with the acid dyes can also be used. The dye mordants are dispersed in the receiving 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. Copolymers or polymer mixtures of vinyl alcohol and N-vinylpyrrolidone, as described, for example, in DE-AS 1 130 284, and also those which are polymers of nitrogen-containing quaternary bases, e.g. Polymers of N-methyl-2-vinylpyridine, as described, for example, in US Pat. No. 2,484,430. Further usable binders are, for example, guanylhydrazone derivatives of alkyl vinyl ketone polymers, as described in US Pat. No. 2,882,156, or guanylhydrazone derivatives of acyl styrene polymers, as described for example in DE-OS 2 009 498.

In general, however, other binders, e.g. Add gelatin. Further polymeric mordants are described, for example, in US Pat. No. 3,709,690, DE-OS 2,315,304, DE-OS 2,445,782, DE-OS 2,551,786 and DE-OS 2,631,521.

The color photographic recording material according to the invention may also contain acidic layers and so-called braking or retarding layers, which together form a so-called integral neutralization system. Such an integral neutralization system can be arranged in a known manner between the layer support and the image receiving layer arranged thereon or at another location in the layer structure, e.g. above the photosensitive layers, i.e. beyond these light-sensitive layers, viewed from the image-receiving layer. The neutralization system is usually oriented so that the braking or retarding layer is between the acid layer and the point at which an alkaline developing liquid or paste is exposed. Such acid layers, brake layers, etc. from both existing neutralization systems are known for example from US 2,584,030, US 2,983,606, US 3,362,819, US 3,362,821, DE-OS 2,455,762, DE-OS 2,601,653, DE- OS 2 716 505, DE-OS 2 816 878. Such a neutralization system can also contain two or more brake layers in a known manner.

• Einerseits kann hierdurch der unerwünschte Zutritt von Licht zu lichtempfindlichen Schichten unterbunden werden und andererseits kann eine solche Pigmentschicht - insbesondere, wenn ein helles oder weißes Pigment, z.B. Ti0₂ verwendet wird - für das erzeugte Farbbild einen ästhetisch angenehmen Hintergrund bilden. Integrale farbfotografische Aufzeichnungsmaterialien mit einer solchen Pigmentschicht sind bekannt, z.B. aus US 2 543 181 und DE-AS 1 924 430. Anstelle einer vorgebildeten opaken Schicht können auch Mittel vorgesehen sein, um solche Schicht erst im Verlauf des Entwicklungsverfahrens zu erzeugen. Entsprechend den beiden erwähnten Funktionen können derartige Pigmentschichten aus zwei oder merheren Teilschichten aufgebaut sein, von denen eine beispielsweise ein weißes Pigment und die andere beispielsweise ein dunkles, lichtabsorbierendes Pigment, z.B. Ruß, enthält.

In a special embodiment, the recording material according to the invention can furthermore have one or more contain pigment-containing opaque layers permeable to aqueous liquids. These can perform two functions:

• On the one hand, this can prevent the undesired access of light to light-sensitive layers, and on the other hand, such a pigment layer - in particular if a light or white pigment, for example Ti0 ₂ - is used - form an aesthetically pleasing background for the color image produced. Integral color photographic recording materials with such a pigment layer are known, for example from US 2 543 181 and DE-AS 1 924 430. Instead of a pre-formed opaque layer, means can also be provided in order to produce such a layer only in the course of the development process. In accordance with the two functions mentioned, such pigment layers can be built up from two or more partial layers, one of which contains, for example, a white pigment and the other, for example, a dark, light-absorbing pigment, for example carbon black.

• 1) einen transparenten Schichtträger
• 2) eine Bildempfangsschicht
• 3) eine lichtreflektierende Schicht
• 4) ein lichtempfindliches Element mit mindestens einer lichtempfindlichen Silberhalogenidemulsionsschicht und einer dieser zugeordneten Kombination aus reduzierbarem Farbabspalter und ED-Vorläuferverbindung
• 5) eine Verzögerungsschicht
• 6) eine saure Polymerschicht
• 7) einen transparenten Schichtträger.

In a particularly preferred embodiment of the invention, the photographic material is an integral color photographic marking material for carrying out the color diffusion transfer process and has, for example, the following layer elements:

• 1) a transparent substrate
• 2) an image receiving layer
• 3) a light reflecting layer
• 4) a light-sensitive element with at least one light-sensitive silver halide emulsion layer and a combination of a reducible color releaser and ED precursor compound assigned to this
• 5) a retardation layer
• 6) an acidic polymer layer
• 7) a transparent substrate.

The mono-sheet material may be composed in such a way here that separate two different components are produced, namely the light-sensitive part (layer elements 1 - 4) and the covering sheet (layer elements 5 - 7), which then aufeinanderge layer side _- considered and are connected to each other, optionally using spacer strips so that a space is formed between the two parts for receiving a precisely measured amount of a developer preparation. The layer elements 5 and 6, which together form the neutralization system, can also be arranged, albeit in the opposite order, between the layer support and the image-receiving layer of the light-sensitive part.

Means can also be provided to introduce a developer preparation between the light-sensitive part and the cover sheet, for example in the form of a laterally arranged, splitable container which when subjected to mechanical forces, its contents pour out between two adjacent layers of the mono-sheet material.

In addition to the aqueous alkali, the developer preparation can also contain developer compounds which, however, have to be matched to the type of color-providing compounds. Other possible components of the developer preparation are thickeners for increasing the viscosity, for example hydroxyethyl cellulose, silver halide solvents, for example sodium thiosulfate, or one of the bis-sulfonylalkane compounds described in DE-OS 2 126 661, opacifiers for producing opaque layers, for example pigments of TiO ₂ , ZnO, barium sulfate, barium stearate or kaolin. Alternatively or additionally, some of these components can also be embedded in one or more layers of the color photographic recording material according to the invention.

example 1 Photosensitive element

• 1. Eine rotsensibilisierte Silberbromidiodidemulsionsschicht aus 0,5 g AgNO₃ mit 0,3 g des Farbabspalters A (= Verbindung 2 aus DE-OS 2 854 946), 0,16 g ED-Verbindung 2, 0,46 g Palmitinsäure- diethylamid (gemeinsamer Ölbildner für A und ED-Verbindung) und 1,15 g Gelatine.
• 2.. Eine Schutzschicht mit 0,6 g Monoacetylierungsprodukt von 4-Methyl-l-phenyl-3-pyrazolidon, 0,12 g 2-Isooctadecyl-5-sulfohydrochinon und 0,6 g Gelatine.
• 3. Eine Härtungsschicht mit 0,1 g Gelatine und 0,12 g Härtungsmittel D.

Apierträger to a coated on both sides with polyethylene _P successive layers were applied. All data refer to 1 m ² .

• 1. A red-sensitized silver bromide iodide emulsion layer consisting of 0.5 g AgNO ₃ with 0.3 g of color releasing agent A (= compound 2 from DE-OS 2 854 946), 0.16 g ED compound 2, 0.46 g palmitic acid diethylamide ( common oil former for A and ED compound) and 1.15 g gelatin.
• 2 .. A protective layer with 0.6 g of monoacetylation product of 4-methyl-1-phenyl-3-pyrazolidone, 0.12 g of 2-isooctadecyl-5-sulfohydroquinone and 0.6 g of gelatin.
• 3. A hardening layer with 0.1 g gelatin and 0.12 g hardening agent D.

Image receiving sheet

• 1. Eine Beizschicht mit 6 g eines Polyurethans gemäß Beispiel 3 der DE-OS 2 631 521 und 5 g Gelatine.
• 2. Eine Härtungsschicht mit 0,1 g Gelatine und 0,15 g Härtungsmittel D.

The following layers were applied to a paper support coated on both sides with polyethylene. The data refer to 1 m ² .

• 1. A pickling layer with 6 g of a polyurethane according to Example 3 of DE-OS 2 631 521 and 5 g of gelatin.
• 2. A hardening layer with 0.1 g gelatin and 0.15 g hardening agent D.

The imagewise exposed photosensitive element and the image-receiving sheet were impregnated with a treatment solution of the composition given below and pressed together on the layer side:

After a contact time of 2 minutes, the sheets were separated from one another and the image-receiving sheet was washed for 30 seconds. After drying, the Dmin / Dmax values of the positive blue-green image were measured.

Examples 2 to 4

The procedure was as in Example 1, but instead of the photosensitive element described there, those were used which instead of the ED compound 2 contained further ED precursor compounds according to the invention in the same molar amount.

The results (Dmin / Dmax) are summarized in the following table:

Example 5 (not according to the invention)

• 1. Blausensibilisierte AgBr-Negativemulsion aus 0,5 g AgNO₃, mit 0,357 g Verbindung B (Gelbfarbstoff freisetzende Verbindung), 0,306 g Verbindung E (ED-Verbindung 4 aus DE-OS 30 06 268) 0,663 g Palmitinsäurediethylamid (ölbildner) und 1,164 g Gelatine.
• 2. Gelbfilterschicht mit 0,16 g Gelbfarbstoff Solvent Yellow 29 (C.I. 21230), 0,07 g 2-iso-Octadecyl-5-sulfo-hydrochinon (Scavenger) und 1,0 g Gelatine.
• 3. Grünsensibilisierte AgBr-Negativemulsion aus 0,5 g _AgN0₃, mit 0,314 g Verbindung C (Purpurfarbstoff freisetzende Verbindung), 0,223 g Verbindung E, 0,537 g Diethyllauramid (ölbildner) und 1,037 g Gelatine.
• 4. Zwischenschicht mit 0,4 g 2-iso-Octadecyl-5-sulfo-hydrochinon, 0,60 g Acetylierungsprodukt von 4-Methyl-1-phenylpyrazolidon(3)(Entwickler) und 1,0 g Gelatine.
• 5. Rotsensibilisierte AgBr-Negativemulsion aus 0,5 g AgNO₃, mit 0,30 g Verbindung A (Blaugrünfarbstoff freisetzende Verbindung), 0,162 g Verbindung E, 0,462 g Palmitinsäure-diethylamid und 0,962 g Gelatine.
• 6. Schutzschicht mit 0,6 g Gelatine
• 7. Opake lichtreflektierende Schicht mit 18 g TiO₂ und 2,57 g Gelatine.
• 8. Schutzschicht mit 4,0 g Gelatine.
• 9. Bildempfangsschicht mit 2,08 g eines polymeren Beizmittels aus 4,4'-Diphenylmethandiisocyanat und N-Ethyldiethanolamin, quaterniert mit Epichlorhydrin gemäß DE-OS 2 631 521, Beispiel 1, und 5,2 g Gelatine.
• 10. Schutz- und Härtungsschicht mit 1,2 g Verbindung D (Härtungsmittel) und 0,6 g Gelatine.

A light-sensitive element of a photographic material according to the invention was produced by successively applying the following layers on a transparent support made of polyethylene terephthalate. The quantities given relate to ¹ _m2 .

• 1. Blue-sensitized AgBr negative emulsion from 0.5 g of AgNO ₃ , with 0.357 g of compound B (yellow dye-releasing compound), 0.306 g of compound E (ED compound 4 from DE-OS 30 06 268), 0.663 g of palmitic acid diethylamide (oil former) and 1.164 g gelatin.
• 2. Yellow filter layer with 0.16 g of yellow dye Solvent Yellow 29 (CI 21230), 0.07 g of 2-iso-octadecyl-5-sulfo-hydroquinone (scavenger) and 1.0 g of gelatin.
• 3. Green-sensitized AgBr negative emulsion of 0.5 g _A gN0 ₃ , with 0.314 g of compound C (purple dye-releasing compound), 0.223 g of compound E, 0.537 g of diethyl lauramide (oil former) and 1.037 g of gelatin.
• 4. Interlayer with 0.4 g of 2-iso-octadecyl-5-sulfo-hydroquinone, 0.60 g of acetylation product of 4-methyl-1-phenylpyrazolidone (3) (developer) and 1.0 g of gelatin.
• 5. Red-sensitized AgBr negative emulsion from 0.5 g AgNO ₃ , with 0.30 g compound A (cyan dye releasing compound), 0.162 g compound E, 0.462 g palmitic acid diethylamide and 0.962 g gelatin.
• 6. Protective layer with 0.6 g gelatin
• 7. Opaque light reflecting layer with 18 g TiO ₂ and 2.57 g gelatin.
• 8. Protective layer with 4.0 g of gelatin.
• 9. Image-receiving layer with 2.08 g of a polymeric mordant consisting of 4,4'-diphenylmethane diisocyanate and N-ethyldiethanolamine, quaternized with epichlorohydrin according to DE-OS 2 631 521, Example 1, and 5.2 g of gelatin.
• 10. Protective and hardening layer with 1.2 g compound D (hardening agent) and 0.6 g gelatin.

The recording material was exposed through the transparent support behind a conventional gray wedge and in an open dish at 22 ° C. for 2 min. developed with a bath of the following composition:

It was then washed and dried for 5 minutes.

Examples 6 and 7 (According to the Invention)

The procedure was as in Example 5, but instead of the photosensitive element described there, those were used which, as scavengers in layers 2 and 4, were 1.5 g of one of the compounds 2 and 13 according to the invention and 1.5 g of dibutyl phthalate each contained oil formers. Processing was carried out as in Example 5.

The recording materials obtained according to Examples 5, 6 and 7 provided transfer images of comparable good color separation.

Before development, the recording materials were exposed to a climate of 60 ° C (with uncontrolled humidity) for 3 d and then processed as in Bei described in game 5, carry-over images were obtained which showed the following percentage increase in fog in relation to the freshly developed samples (positive values mean increase in fog):

As can be seen from the table, the compounds according to the invention can also be used particularly advantageously as oxform scavengers in photographic layers because of the significantly lower tendency to fog.

Formula attached to the examples.

Claims (5)

1. Color photographic recording material with at least one light-sensitive silver halide emulsion layer and an associated non-diffusing coloring compound, which contains in at least one light-sensitive silver halide emulsion layer or a non-light-sensitive binder layer a non-diffusing electron donor precursor compound (ED precursor compound), from which a non-diffusing ED- under alkaline development conditions Compound is formed, characterized in that the ED precursor compound corresponds to the following formula I:

in which mean: R ^{1 is} a carbocyclic or heterocyclic aromatic group; and R ^{2 is} hydrogen, alkyl, alkenyl, aryl or acyl;
wherein at least one of the radicals R and R ² contains a ballast radical. 2. Color photographic recording material with at least one light-sensitive silver halide emulsion layer and an associated combination of a non-diffusing reducible coloring compound, which is able to release a diffusible dye in the reduced state under the alkaline development conditions, and a non-diffusing electron donor precursor compound (ED precursor compound) which forms a non-diffusing electron donor compound (ED compound) under the alkaline development conditions, which is able to reduce the non-diffusing coloring compound under the alkaline development conditions, characterized in that the recording material contains a compound of the following formula I as the ED precursor compound:

in which mean: _R ^{1 is} a carbocyclic or heterocyclic aromatic group, and - _R ^{2 is} hydrogen, alkyl, alkenyl or acyl
wherein at least one of the radicals R ¹ and R ² contains a ballast radical. 3. Recording material according to claim 1 or 2, characterized in that R ^{1 represents} an optionally substituted phenyl group. 4. Recording material according to claim 1 or 2, characterized in that R ^{2 is} a carbamoyl radical or an acyl radical which is derived from an aliphatic or aromatic carboxylic acid. 5. Recording material according to claim 2, characterized in that a compound of the following formula II is used as the non-diffusing reducible coloring compound

in what mean R ^{1 is} 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, amino, alkylamino, dialkylamino finally cyclic amino groups, acylamino, alkylthio, alkoxy, aroxy, sulfo, or a group which together with _R ^{2 completes} a fused ring; _R ⁴ alkyl; R ^{5 is} hydrogen; A the rest of a diffusible dye or dye precursor; X is a bivalent link; and m 0 or 1.