DE3872365T2 - COLOR-FORMING POLYMERIC COUPLERS. - Google Patents

Description

This invention relates to new polymeric color couplers and their use in photographic material.

There is currently a sensitive camera film material on the market that consists of silver halide and color couplers in an emulsion layer of silver halide, which produces a so-called monochromatic color image when color developed. This material has certain advantages over conventional sensitive black-and-white camera film material in that the dye images are practically grain-free compared to the silver image obtained with high-sensitivity film material. In addition, such a film material can be processed using chemical methods customary for processing color film. Most processing plants today are only set up to process color film, so it is extremely advantageous that the monochromatic sensitive camera film material can be processed in a color film processing system.

However, in order to obtain a negative that is sufficiently dense for visual inspection and has a sufficient light absorption range for copying on all types of black-and-white paper, including variable contrast paper, it has proven necessary to add a yellow, cyan and magenta color coupler to the silver halide emulsion. Since these can only be stored in the silver halide emulsion as solutions in oil, a large amount of oil had to be present in the photographic material in order to dissolve all the color couplers and keep them in solution.

This has resulted in serious disadvantages. For example, oil residues remain on the cutting device when the film is cut. In addition, since the silver halide layer has to be thick, the presence of oil droplets reduces the sharpness. In addition, a soft layer is created which can lead to mechanical damage.

A process has now been found for incorporating cyan, magenta and yellow colour couplers in a single silver halide emulsion layer without the use of oil as a solvent.

According to the present invention there is provided a polymeric color coupler consisting of the residue of three monomeric color couplers of the formulas:

wherein R₁ is hydrogen, alkyl, chlorine or bromine, R₂ is a divalent organic radical and W₁, W₂ and W₃ each represent an active color former radical which is capable of forming a dye upon chromogenic development of exposed silver halide material with a primary aromatic amine color developing agent, wherein W₁ forms a yellow dye, W₂ forms a magenta dye and W₃ forms a cyan dye.

Preferably, the three radicals W₁, W₂ and W₃ are present in the polymers in such a ratio that a black or blackish dye is obtained during color development.

W₁, W₂ and W₃ can be any previously known coupling component, such as those described below. Preferably R₁ is hydrogen or methyl. Preferably the divalent organic radical R₂ can be the radical of a urethane, urea, carbonate, ester, ether, ketone or amide. Above all, however, it is a simple amide bond -C(O)-NH-.

The polymeric color coupler of the type described can be formed as a polymeric latex which is not isolated but used as such. Alternatively, it can be formed as a water-soluble solid. When formed as a polymeric latex, preferably at least one other simple, non-color-coupling photographically inert comonomer is present in the polymer unit. When the polymer is to be incorporated as a latex in the photographic material, the presence of other monomers in the polymer is particularly desirable. In this case, a latex polymer should be prepared which has optimal physical properties such as glass transition temperature, miscibility with the gelatin used in the preparation of the coating solutions, a suitable refractive index, as well as favorable copolymerization rate between the coupling monomers and the photographically inert comonomers and the ability to impart a lower viscosity to the mixture, as well as sufficient miscibility with the mixture of coupling monomers.

If the polymeric colour coupler of the type described is formed as a water-soluble solid, the polymer contains 40-60 wt.% of the remainder of a monomer of the formula

wherein R₁ has the meaning given in claim 1, L represents an alkylene or interrupted alkylene linking group and R¹ and R¹¹ represent alkyl groups having 1 to 4 carbon atoms and X⁻ represents an anion.

Preferably, L represents an alkylene chain having 2 to 6 carbon atoms or an interrupted alkylene chain having 2 to 6 carbon atoms, wherein the chain is a oxygen atom or an -NH group.

A particularly suitable monomer residue of this type has the formula V:

If the polymeric color coupler is formed as a polymer latex or water-soluble polymer, the comonomers that may be present are methyl acrylate, ethyl acrylate, butyl acrylate, ethylhexyl acrylate, vinyl acetate; hydroxyethyl methacrylate, hydroxypropyl methacrylate; methacrylic acid, acrylic acid, itaconic acid, 2-carboxyethyl acrylate and salts thereof, acrylamide, methacrylamide, N-hydroxymethylacrylamide, styrene, N-vinylpyrrolidone, 1-vinylimidazole; 4-vinylpyridine, dimethylaminoethyl methacrylate, tetrahydrofurfuryl methacrylate, sulfoethyl methacrylate, vinylsulfonic acid and salts thereof, acrylonitrile and vinylidene chloride, although this list is not intended to be comprehensive.

In addition, crosslinking monomers such as divinylbenzene, ethylene dimethacrylate, trivinylcyclohexane and trimethylolpropane triacrylate may be present.

The surface-active agents used in the manufacture of the polymer latex can be any of those well known in the art, for example non-ionic wetting agents, including alcohol ethoxylates, sorbitan esters, arylphenol alkoxylates, alkyl alkanolamides, anionic wetting agents, including alkyl sulfates and sulfonates, sulfosuccinates, arylsulfonates, polyalkoxysulfates, alkyl phosphates, arylphenol phosphates, alkyl taurinates, sarcosinates, and copolymerizable surfactants such as allyl sulfosuccinates, although this list is not intended to be exhaustive.

The initiators and initiator systems used to prepare the latexes can be persulfates, azo compounds, peroxides, or any of the other well-known initiators used in emulsion polymerization, including redox systems. Examples of these initiator systems can be found in the book "Emulsion Polymerization" by D. Blackley, Applied Science Publishers, 1975, particularly pages 155 to 250.

In the processes for producing the latexes, methods such as seed polymerization and core-shell methods, as well as self-feeding methods and other methods well known in the art can be used. The latexes can be produced in bulk, semi-continuously or continuously using known equipment.

According to another feature of the present invention, there is provided a photographic material comprising at least one gelatin-silver halide emulsion layer containing a polymeric color coupler of the type described. Particularly preferably, the photographic material contains a polymeric color coupler consisting of the residues of monomers A, B and C shown below.

In one embodiment, the polymeric color coupler of the type described is present in the silver halide emulsion layer as a polymeric latex.

In a further embodiment, the color coupler of the type described is added to the silver halide emulsion layer as an aqueous solution.

In the polymeric color coupler of the present invention, all monomeric color couplers described in the prior art can be used. The color coupler part of the monomer can have ballast groups or leaving groups, so that, for example, the color coupler can serve as a divalent coupler.

Suitable yellow dye-forming monomeric colour couplers include couplers of the general formula VI:

wherein R₃, R₄, R₅ and R₆ each represent hydrogen, halogen, alkoxy, sulfoxy or sulfonamide, R₁ and R₂ have the definition given above, R₇ represents hydrogen or a leaving group and L₁ and L₂ represent direct bonds or -NH-.

Particularly useful linking groups R₂ are -CO-NH- and -O-CH₂-CH₂-NH-SO₂-.

Preferably, one of L₁ and L₂ represents a direct linkage. Such a monomer is, for example, monomer B, which is used in the following examples. This monomer has the formula VII:

Another example of a monomer of the general formula VI has the formula VIII:

Another example of a monomer of general formula VI that has a leaving group is the monomer of formula IX:

Monomeric yellow color couplers of formula VI are described in US 40 80 211.

Another class of yellow dye-forming monomeric color couplers has a pivaloyl end group instead of the benzoyl end group.

Such color couplers have the general formula X:

where R₁, R₂, R₆ and R₇ have the meanings given above.

An example of such a coupler has the formula XI:

Suitable magenta colour-forming monomeric colour couplers include couplers of the general formula XII:

where R₁ and R₂ have the meaning given above, R₈ is hydrogen or a leaving group and R₁₀, R₁₁ and R₁₂ are each hydrogen, halogen or alkoxy. The alkoxy group preferably has an alkyl radical with up to 6 carbon atoms.

Preferably R₁ is hydrogen or -CH₃.

Preferably R₂ is -CO-NH-.

However, other valuable linking groups R₂ are -CO-NH(CH₂)xO-CO-NH, where x is 2 to 6,

and

where in the above two formulas the phenylene group is optionally substituted by chlorine or alkyl having 1 to 4 carbon atoms.

Particularly valuable monomers of formula XII are those in which at least two of R₁₀, R₁₁ and R₁₂ represent chlorine atoms.

A possible leaving group R₇ or R₈ is, for example, the group -S-R₇, where R₇ is a long-chain alkyl group with more than 10 carbon atoms or a substituted phenyl group with at least one alkyl or alkoxy group. If R₇ is an alkyl group, this preferably has 12 to 20 carbon atoms in the chain.

Other possible leaving groups R�7 or R�8 are

in question.

Examples of monomers of formula XII are:

and Monomer A, which is used in the following examples and has the formula

owns.

Monomeric magenta color couplers of formula XII are described in EP 133262.

Other magenta dye-forming monomeric color couplers are those of the general formula XVI:

where R₁, R₈ and R₁₀ have the meaning given above and R₁₉ represents alkyl, dialkylamino, optionally substituted phenyl and optionally substituted acylamino. Possible substituents in the phenyl or acylamino group are alkyl groups with 2 to 6 carbon atoms and chlorine.

The preparation of these couplers can be carried out by reacting magenta colour couplers of the formula

with acryloyl or methacryloyl chloride.

Examples of cyan dye-forming monomeric color couplers are phenol couplers of the general formula XVIII:

and the general formula XIX:

and a naphthol coupler of the general formula XX:

wherein in the above three formulas R₁ and R₁₂ have the meaning given above, R₁₄ is hydrogen or a leaving group such as a halogen atom or a substituted alkoxy group, R₁₃ is a hydrogen atom or an alkyl group having 1 to 5 carbon atoms, R₁₅ is an optionally substituted alkyl or acylamino group or a para-cyanoaniline group, and R₁₇ is a linking group and y is 0 or 1, and R₁₆ is an alkoxy, amino, amido or sulfonamido group or a hydrogen atom.

Preferably R₁ is hydrogen or methyl.

As linking groups R₁₇, for example, alkylene chains with 2 to 6 carbon atoms, including interrupted alkylene chains, as well as an alkyl group, e.g.

and

in question.

Preferably, interrupted alkylene chains

2 to 6 carbon atoms and an -O- or -NH- group in the chain.

Examples of monomers of formula XVIII are:

This is monomer C, which is used in the following examples. Other examples of monomers of formula XVIII have the formulas:

Examples of monomers of formula XIX are those of the formulas:

and

Examples of monomers of formula XX are those of the formulas:

and

Monomeric colour couplers of the general formula XX are described in GB-A-2133170.

The colour couplers of the type described are particularly useful for monochromatic silver halide sensitive camera film material. After imagewise exposure, the photographic material is developed in a colour developing bath with a para-phenylenediamine developer to produce a developed silver image and a black colour image. The material is then subjected to a bleach-fixing treatment which removes the developed silver image and the unexposed silver halide, leaving the black colour negative image which can be used for copying on all types of black and white paper, including variable contrast paper.

The color couplers of the type described can also be used to produce monochromatic paper, i.e. paper that can be processed using chemical color processing methods to produce a black color image instead of a silver image. Such paper can be used particularly advantageously for producing proof copies.

Silver halide images can also be intensified using the color coupler of the type described, especially when, as happened a few years ago, the price of silver prohibits its use in those photographic processes that require a highly concentrated silver image.

The photographic material of the present invention preferably contains gelatin as a binder in the silver halide emulsion layer.

Any of the silver halides normally used in photography can be used as the halide, e.g. silver bromide, silver iodobromide, silver chloride, silver chlorobromide and silver iodochlorobromide. The silver halide grains can be both optically and chemically sensitized. The silver halide emulsion can contain stabilizers, bactericides and any other additives normally found in photographic silver halide emulsions. The gelatin can be hardened and contain coating aids, as is usual in the manufacture of coated silver halide emulsions.

The support for the sensitive camera film material can be any of the usual light-permeable supports used in photography, e.g. a support made of subbed polyester, polycarbonate or polystyrene, or it can be a support made of cellulose triacetate or cellulose acetate butyrate. If the material is to be used for proof copies, the support can be any of the usual materials used for photographic printing. used opaque support, e.g. a baryta-coated paper support or a polyethylene-laminated paper support.

The attached examples serve to explain the invention.

example 1

To a solution of oleylmethyltaurine sodium salt containing 0.16 g in 15.8 ml of water and kept at 80°C in a 100 ml reaction vessel was added 70 mg of potassium persulfate and 10 mg of sodium metabisulfite under a nitrogen atmosphere and mechanical stirring.

A monomer solution was prepared by dissolving 0.34 g of monomer A (magenta monomer), 0.34 g of monomer B (yellow monomer) and 0.34 g of monomer C (cyan monomer) in 2.00 g of hydroxypropyl methacrylate and 3.00 g of butyl acrylate. The vessel containing this solution was maintained at approximately 30 to 40°C. A surfactant solution was prepared by dissolving 0.16 g of oleylmethyltaurine sodium salt and 40 mg of potassium persulfate in 5.8 g of water.

The surfactant and monomer solutions were then slowly added to the 100 ml vial containing the initiator solution described at the beginning. These additions were made over a period of 2 hours. The latex formed in the 100 ml vial was kept at 80ºC for 1½ hours. The contents were then cooled and filtered.

Isolation yielded a latex with a solids content of 22% and a particle size of 71 nm. The total amount of coagulated material present in the vessel was only 0.04 g.

Color photographic material was produced using the latex as it was synthesized. 2.2 ml of an uncolored emulsion of iodobromide twin crystals and gelatin were mixed with 0.4 ml of the latex and 7 ml of water. 0.4 ml of water was added to this emulsion. 0.4 ml of a 3% solution of a triazine hardener was added to this emulsion. The The emulsion was then coated onto a transparent cellulose triacetate support, giving a silver deposit of 12 mg/dm². Examination of the dried coating under green light showed a transparent, glossy coating. This photographic material was then exposed to a white light source for 10 seconds and processed in a color developing solution at 38ºC for 3.25 minutes.

The recipe for the development solution used is as follows:

Potassium carbonate 37.5 g

Sodium sulphite 4.5 g

Nitrilotriacetate (complexing agent) 2 g

Sodium hydroxide 0.6 g

Sodium bromide 0.9 g

Hydroxylamine sulfate 2.8 g

Developer of the formula below 5.25 g

Water 1 litre

The formula of the developer used is:

The photographic material was then placed in a bleach bath where it remained for 6.5 minutes at 35ºC.

The recipe for the bleach bath used is as follows:

Ammonium bromide 150 g

1.8 M EDTA iron (III) salt 150 ml

Sodium nitrate 20 g

Water to 1 liter

The material was then placed in a fixer bath where it remained for 6½ minutes at 35ºC. The recipe for the fixer bath is as follows:

Ammonium thiosulfate (80% w/v) 190 ml

Sodium sulphite 19 g

EDTA sodium salt 1.5 g

Water to 1 liter

The material was then washed in water at 30ºC for 3 minutes and then dried. A neutral grey image was present on the photographic material. This image had the visible absorption spectrum shown in the accompanying Figure 1. This shows that the material has good absorption in the blue, green and red regions of the visible spectrum.

Two further samples of photographic material were prepared as described above, with the difference that the silver halide emulsion contained a green sensitizing dye and a red sensitizing dye. In this way, the material was panchromatically sensitized.

Both samples were image-exposed in a plate camera and then processed as described above.

One of the negatives obtained was placed in a photographic enlarger and prints were made on ordinary non-optically sensitized black and white paper. After processing the exposed paper, a bright image with clear highlights and dark shadows was obtained.

The other of the negatives obtained was placed in a photographic enlarger fitted with a filter to enable prints to be made on variable contrast photographic paper. Examination of the image on the base board of the enlarger indicated that a No. 2 contrast filter should be used. This was placed in the correct position together with a sheet of variable contrast material underneath and a copy was made using the negative. After processing, the copy was examined. As before A bright print with clear highlights and dark shadows was obtained.

It follows that the photographic material of the present invention can be used to produce negatives which can be used to produce copies on both ordinary black and white paper and on black and white photographic papers with variable contrast.

Example II Water-soluble polymeric color coupler of the kind described.

p-Toluenesulfonic acid (4 g) was dissolved in technical alcohol (30 ml). A sufficient amount of the monomer dimethylaminoethyl methacrylate was added with stirring to raise the pH to 7. 5.2 g were required. This solution was placed in a 50 ml flask and 1 g of monomer A (magenta monomer), 0.5 g of monomer B (yellow monomer) and 0.5 g of monomer C (cyan monomer) were added. The flask was equipped with a condenser, nitrogen supply, oil bath and magnetic stirrer. Nitrogen was bubbled through for 10 minutes at room temperature. The flask was then heated to 70ºC and maintained at this temperature.

A solution of radical initiator containing 0.5 g of azobis(isobutyronitrile) in 50 mL of technical alcohol was prepared. 4.8 mL of this solution was added to the flask. After 2 hours, a further 1.2 mL of the initiator solution was added and this was repeated after a further 2 hours. After a reaction time of 7 hours, the contents of the flask were added to ether (500 mL) whereupon a sticky brown solid separated. This solid was dissolved in technical alcohol and reprecipitated with ether to give a free-flowing white powder. Yield 7.13 g (67.3%). This powder was found to be completely water soluble.

0.1 g of this solid was then added to an emulsion prepared as in Example 1.

A clear, glossy coating was prepared as described in Example 1. Examination under green light showed a clear, glossy coating. The coating was exposed to white light for 10 seconds as in Example 1 and then processed as described in Example 1.

A grayish image was obtained which was sufficiently dense and had sufficient absorption over the entire visible range to be used as a negative for making copies on black-and-white photographic material as shown in Figure 2.

Claims (15)

1. Polymeric colour coupler consisting of the residue of three monomeric colour couplers of the formulas: wherein R₁ is hydrogen, alkyl, chlorine or bromine, R₂ is a divalent organic radical and W₁, W₂ and W₃ each represent an active color former radical which is capable of forming a dye upon chromogenic development of exposed silver halide material with a primary aromatic amine color developing agent, wherein W₁ forms a yellow dye, W₂ forms a magenta dye and W₃ forms a cyan dye. 2. A polymeric color coupler according to claim 1, wherein R₁ is hydrogen or methyl. 3. A polymeric color coupler according to claim 1, wherein R₂ represents the residue of a urethane, urea, carbonate, ester, ether, ketone or amide. 4. A polymeric color coupler according to claim 3, wherein R₂ is -C(O)-NH-. 5. A polymeric color coupler according to claim 1, wherein the polymer is formed as a latex which is not isolated but used as such. 6. A polymeric color coupler according to claim 5, wherein the polymer consists of units derived from at least one non-color-coupling, photographically inert comonomer. 7. Polymeric color coupler according to claim 6, wherein the photographically inert comonomer is methyl acrylate, ethyl acrylate, butyl acrylate, ethylhexyl acrylate, vinyl acetate; hydroxyethyl methacrylate, hydroxypropyl methacrylate; methacrylic acid, acrylic acid, itaconic acid, 2-carboxyethyl acrylate and salts thereof, acrylamide, methacrylamide, N-hydroxymethylacrylamide, styrene, N-vinylpyrrolidone, 1-vinylimidazole; 4-vinylpyridine, dimethylaminoethyl methacrylate, vinylsulfonic acid and salts thereof, acrylonitrile and vinylidene chloride. 8. Polymeric color coupler according to claim 1, wherein the polymer is formed as a water-soluble solid. 9. Polymeric colour coupler according to claim 8, wherein in the polymer 40-60 wt.% of the residue of a monomer of the formula wherein R₁ has the meaning given in claim 1, L represents an alkylene or interrupted alkylene linking group and R¹ and R¹¹ represent alkyl groups having 1 to 4 carbon atoms and X⊃min; represents an anion. 10. Polymeric colour coupler according to claim 1, consisting of the residue of a yellow dye-forming monomeric colour coupler of the general formula: wherein R₃, R₄, R₅ and R₆ each represent hydrogen, halogen, alkoxy, sulfoxy or sulfonamido, R₁ and R₂ have the definition given in claim 1, R₇ represents hydrogen or a leaving group and L₁ and L₂ represent direct linkages or -NH-. 11. Polymeric colour coupler according to claim 1, consisting of the residue of a yellow dye-forming monomeric colour coupler of the general formula: wherein R₁ and R₂ have the meaning given in claim 1 and R₆ and R₇ have the meaning given in claim 10. 12. A polymeric color coupler according to claim 1, consisting of the residue of a magenta dye-forming monomeric color coupler of the general formula: wherein R₁ and R₂ have the meaning given in claim 1, R₈ is hydrogen or a leaving group, and R₁₀, R₁₁ and R₁₂ each represent hydrogen, halogen or alkoxy. 13. A polymeric color coupler according to claim 1, consisting of the residue of a magenta dye-forming monomeric color coupler of the general formula: wherein R₁ has the meaning given in claim 1 and R₈ and R₁₀ have the meaning given in claim and R₉ is alkyl, dialkylamino, optionally substituted aryl and optionally substituted acylamino. 14. A polymeric color coupler according to claim 1, consisting of the residue of a cyan dye-forming monomeric color coupler which is a phenol coupler of the general formula: or a phenol coupler of the general formula: or a naphthol coupler of the general formula: wherein in the above three formulas R₁ and R₁₂ have the meaning given in claim 13, R₁₄ is hydrogen or a leaving group such as a halogen atom or a substituted alkoxy group, R₁₃ is a hydrogen atom or an alkyl group having 1 to 5 carbon atoms, R₁₅ is an optionally substituted alkyl or acylamino group or a para-cyanoaniline group and R₁₇ is a linking group and y is 0 or 1 and R₁₆ is an alkoxy, amino, amido or sulfonamide group or a hydrogen atom. 15. Photographic material with at least one gelatin-silver halide emulsion layer containing a polymeric color coupler according to claim 1.