DE3883446T2 - Silver halide color photographic materials and methods. - Google Patents

Description

This invention relates to novel acylacetanilide photographic color couplers and photographic elements containing them.

It is well known in the photographic art that color images can be obtained from imagewise exposed silver halide emulsions by developing them with a primary aromatic amine color developing agent in the presence of a color coupler. The oxidized color developing agent produced in the silver halide development areas couples with the coupler to form a dye. The coupler may be present in the developer solution, but is usually present in the sensitive photographic material.

In order for image dye-forming couplers to be of practical use, they must react with oxidized developing agent to form a dye both effectively and at an appropriate rate. Furthermore, the dyes so formed must have an acceptable hue and exhibit sufficient stability under various storage conditions.

Most of the examples of yellow image dye-forming couplers that have been used in commercial photographic products are derived from two classes of acylacetanilides, namely pivaloylacetanilides and benzoylacetanilides. Historically, benzoylacetanilide couplers have exhibited greater reactivity to oxidized developing agents than their pivaloylacetanilide analogues, and furthermore, the extinction coefficients of the dyes derived from them can be greater. However, the hue of these dyes is generally deeper and their stability to exposure to light, heat and moisture is generally poorer. Benzoylacetanilides also have a greater tendency to crystallize, either in the coupler solvent or in the photographic coatings.

Benzoylacetanilides have been largely displaced by pivaloylacetanilides over the last thirty years due to the superior dye properties provided by the latter. However, the present invention relates specifically to the use of benzoylacetanilides as yellow image dye-forming couplers.

European Patent Application 0 126 433 is broadly concerned with pivaloylacetanilide couplers, but also discloses three benzoylacetanilides (compounds 4, 10 and 11); however, these compounds do not fall within the claims of the present invention. US Patent 4,587,207 generally deals with both pivaloylacetanilide and benzoylacetanilide couplers in its general description, but the specific description is limited to pivaloylacetanilides. Compound 17 of this patent has structural features consistent with the couplers of the present invention, but the ballast group is in a different position and has a sulfonamido group on the anilide ring. The properties of the compound are not described. Similar couplers are described in Japanese Patent Publication Kokai 59-174839. Compound 9 of this reference also has structural features consistent with the couplers of the present invention, but has an alkyl ester group on the anilide ring.

There is a continuing need for yellow dye-forming acylacetanilide couplers which provide excellent dye density in a silver halide photographic material and process, as well as excellent image contrast properties and which provide image dyes of excellent hue and high extinction coefficients. Furthermore, there is a need for such couplers which have improved dark storage properties.

It has now been found that such properties in the case a silver halide color photographic element comprising a support having thereon at least one silver halide photographic emulsion layer and a non-diffusing para-R-oxybenzoylacetanilide yellow dye-forming coupler comprising a combination of (a) a para-hydroxyphenylsulfonylphenoxy coupling-off group in the coupling position, (b) a chloro or trifluoromethyl group in the ortho position on the anilide moiety, and (c) a group on the anilide moiety selected from (i) an aliphatic hydrocarbon group bonded to the anilide moiety directly or through a linking group consisting of carbamoyl (-CONH-), sulfonate (-O-SO₂-), phosphate (-O-PO₂-) or alkylene, (ii) chlorine, and (iii) trifluoromethyl; wherein the anilide moiety has no further substituents; wherein the coupler has at least one ballast group on at least one of the anilide and para-R-oxybenzoyl residues; and wherein R is an unsubstituted or substituted cyclic or non-cyclic aliphatic hydrocarbon group.

Suitable non-diffusing color couplers correspond to the formula:

where:

R¹ represents an unsubstituted or substituted cyclic or non-cyclic aliphatic hydrocarbon group;

Y is chloro or trifluoromethyl;

Z is halogen, trifluoromethyl or -L-R², where:

R² is an unsubstituted or substituted aliphatic hydrocarbon group,

L is a direct bond or a carbamoyl (-CONH-), sulfonate (-O-SO₂-), phosphate (-O-PO₂-), or an alkylene group; and

at least one of the radicals R¹ and Z has a ballast group .

The benzoylacetanilide image dye-forming couplers of the invention are readily soluble in common coupler solvents and, when incorporated into a color negative photographic material, exhibit excellent dye densities and contrast characteristics. Furthermore, these couplers produce dyes of excellent hue and high extinction coefficient which are stable under a wide range of conditions, particularly when stored in the dark, which is of fundamental importance for color negative materials.

Examples of groups represented by R¹ are alicyclic groups having 4 to 6 carbon atoms and noncyclic groups having 1 to 20 carbon atoms, which may be substituted or unsubstituted and which may be saturated or unsaturated, such as methyl, ethyl, n-butyl, n-dodecyl, n-hexadecyl and n-undecyl.

The ballast group may be part of R¹, in which case R¹ may be an alkyl group having 10 to 16 carbon atoms.

The ballast group can also be attached via the substituent Z. In such cases, the group that forms the ballast group on the anilide ring has a strong influence on the solubility of the coupler in the coupler solvent and also on its tendency to crystallize in photographic coatings. Linking groups or atoms that contribute to favorable solubility characteristics of the coupler include carbamoyl, sulfonate, phosphate and alkyl. It should be noted that linking groups or atoms that increase coupler crystallization problems include amide and sulfonamide groups and the oxygen atom.

If the ballast group is present in Z, R¹ preferably has 1 to 4 carbon atoms.

The aliphatic hydrocarbon groups represented by R² can be any group, such as those specified for R¹.

Benzoylacetanilide couplers 1 to 5 described below are examples of couplers of the invention from which dyes are derived which are characterized by excellent dark/humidity stability. Furthermore, these compounds exhibit all other properties required for an image dye-forming coupler intended for use in color negative photographic materials.

Me here means CH₃-.

The present couplers can be prepared by methods known per se. The synthesis procedure for coupler 8 (a coupler outside the scope of the present invention, but an analogous compound) described below is illustrative of all compounds of the invention.

Manufacturing of Coupler 8 1) 4-Dodecyloxyacetophenone

With stirring, a mixture of 4-hydroxyacetophenone (54.5 g), 1-bromodecane (152.7 g), potassium carbonate (83.0 g) and acetone (800 ml) was heated under reflux conditions for 40 hours. The mixture was passed through a steam-heated filter and the filtrate was filtered off under reduced pressure The residue was recrystallized from petroleum ether (bp. 40 - 60ºC) to give 91.0 g of reaction product (75%). 2) Ethyl 4-dodecyloxybenzoyl acetate

A mixture of sodium hydride (25.5 g, 60% mineral oil dispersion), diethyl carbonate (115.0 g) and tuloul (300 ml) was heated to 70 °C with stirring. 4-Dodecyloxyacetophenone (74.4 g) in toluene (150 ml) was added over 20 minutes. The mixture was heated to 80 °C with stirring for 2 hours, after which it was cooled and carefully acidified with glacial acetic acid. The mixture was then diluted with water and extracted with ethyl acetate (300 ml). The extract was dried over magnesium sulfate and evaporated under reduced pressure. Xylene was then added to the residue and the resulting solution was again evaporated under reduced pressure to remove traces of diethyl carbonate. The residue (101.4 g) was used in the next step without further purification. 3) Methyl 4-chloro-3-[2-(4-dodecyloxybenzoyl)acetoamido]benzoate

With stirring, a mixture of ethyl 4-dodecyloxybenzoyl acetate (45.6 g, crude), methyl 3-amino-4-chlorobenzoate (20.0 g) and xylene (400 mL) was slowly distilled over 3 hours to collect 200 mL of distillate. The solution was allowed to cool and the resulting precipitate was filtered off. The reaction product was recrystallized from acetonitrile to give a fluffy white solid (33.9 g, 60.8%). 4) Methyl 4-chloro-3-[2-chloro-2-(4-dodecyloxybenzoyl)acetamidobenzoate

Sulfuryl chloride (9.5 g) was added over a period of 30 minutes to a solution of the above solid (33.0 g) in dichloromethane (300 mL). The solution was stirred at room temperature for an additional hour before being concentrated under reduced pressure. The residue crystallized when slurried with acetonitrile. The resulting solid was recrystallized from acetonitrile to give 32.0 g (91%) of pure product. 5) Methyl 4-chloro-3-[2-(4-dodecyloxybenzoyl)-2-(4-((4-hydroxyphenylsulfonyl))phenoxy)acetamido]benzoate

Nitrogen gas was passed through a solution of methyl 4-chloro-3-[2-chloro-2-(4-dodecyloxybenzoyl)acetamido]benzoate (22 g) and sulfonyldiphenol (40 g) in DMF (300 ml) for 30 minutes before triethylamine (12.12 g) was added dropwise with stirring. The temperature was raised to 45-50 °C and maintained for 2 hours. The reaction mixture was then poured into 5% hydrochloric acid (300 ml) with stirring and the mixture was stirred for 1 hour. The aqueous phase was decanted and the remaining residual gummy product was dissolved in ethyl acetate (300 ml). The organic solution was washed successively with sodium carbonate solution (300 ml) and water (300 ml), dried over magnesium sulfate and evaporated to dryness. The resulting gummy product was purified by elution through a silica gel column using mixtures of ethyl acetate and petroleum ether (bp. 60 - 80ºC) as eluting solvent. The appropriate fractions were combined and concentrated under reduced pressure, and the resulting solid was recrystallized from ethyl acetate/petroleum ether to give the desired product as a white powder (14 g, 46%).

HPLC analysis 99%, mp 153 - 8ºC.

Elementary analysis:

C₄₁H₄₆ClNO₄S calcd: C: 64.3; H: 6.2; Cl: 4.9; N: 1.8; S: 4.3%;

found: 64.4; 6.0; 4.7; 1.8; 4.2.

The dye-forming couplers of this invention can be used in the manner and for the purposes that dye-forming couplers have heretofore been used in the photographic art.

Typically, the couplers are associated with a silver halide emulsion layer that has been coated on a support to form a photographic element. As used herein, the term "associated" means that the coupler is incorporated into the silver halide emulsion layer or is present in a layer adjacent to the silver halide emulsion layer so that it is capable of reacting with silver halide development products during the development process.

The photographic elements can be color elements or multicolor elements. In the case of a multicolor element, the yellow dye-forming couplers of this invention are usually associated with a blue-sensitive emulsion, although they can also be associated with an emulsion that has been sensitized to a different region of the spectrum, or the coupler can be associated with a panchromatically sensitized, orthochromatically sensitized, or unsensitized emulsion. Multicolor elements contain dye image-forming units that are sensitive to each of the three primary regions of the spectrum. Each unit may be constructed from a single emulsion layer or from multiple emulsion layers sensitive to a particular region of the spectrum. The layers of the element, including the layers of the image forming units, may be arranged on the support in various known orders.

A typical multicolor photographic element comprises a support having thereon a yellow dye image-forming unit comprising at least one blue-sensitive silver halide emulsion layer having associated therewith at least one yellow dye-forming coupler, at least one of the yellow dye-forming couplers being a coupler of this invention, and further comprising thereon magenta and cyan color image-forming units comprising at least one green- or red-sensitive silver halide emulsion layer having associated therewith at least one magenta or cyan dye-forming coupler. The element may comprise other additional layers, e.g., filter layers.

In the following discussion of suitable materials for use in the emulsions and elements of this invention, reference is made to Research Disclosure, December 1978, No. 17643, published by Industrial Opportunities Ltd., The Old Harbourmaster's, 8 North Street, Emsworth, Hants P010 7DD, United Kingdom. This publication is hereinafter referred to as "Research Disclosure".

The silver halide emulsions used in the elements of this invention can be either negative-working or positive-working emulsions. Suitable emulsions and their preparation are described in Research Disclosure, Sections I and II and the publications cited therein. Suitable binders for the emulsion layers and other layers of the elements of this invention Invention are described in the Research Disclosure, Section IX and the references cited therein.

In addition to the couplers of this invention, the elements of this invention may contain additional couplers such as those described in Research Disclosure, Section VII, Paragraphs D, E, F and G and the references cited herein. The couplers of this invention and any additional couplers may be incorporated into the elements and emulsions as described in Research Disclosure, Section VII, Paragraph C and the references cited herein.

The photographic elements of this invention, or individual layers thereof, may contain brighteners (see Research Disclosure, Section V), antifoggants and stabilizers (see Research Disclosure, Section VI), antistaining agents and image dye stabilizers (see Research Disclosure, Section VII, paragraphs I and J), light absorbing and light scattering materials (see Research Disclosure, Section VIII), hardeners (see Research Disclosure, Section XI), plasticizers and lubricants (see Research Disclosure, Section XII), antistaining agents (see Research Disclosure, Section XIII), matting agents (see Research Disclosure, Section XVI), and development modifiers (see Research Disclosure, Section XXI)

The photographic elements can comprise a variety of supports, such as those described in Research Disclosure, Section XVII and the references cited therein.

The photographic elements may be exposed to actinic radiation, typically actinic radiation in the visible region of the spectrum, to form a latent image as described in the Research Disclosure, Section XVIII, whereupon they can be developed to form a visible dye image as described in Research Disclosure, Section XIX. Development to form a visible dye image includes the steps of contacting the element with a color developing agent to reduce developable silver halide and to oxidize the color developing agent. Oxidized color developing agent then reacts with the coupler to form a dye.

Preferred color developing agents are p-phenylenediamines. Particularly preferred are 4-amino-3-methyl-N,N-diethylaniline hydrochloride; 4-amino-3-methyl-N-ethyl-N-β-(methanesulfonamido)ethylaniline sulfate hydrate; 4-amino-3-methyl-N-ethyl-N-β-hydroxyethylaniline sulfate; 4-amino-3-β-(methanesulfonamido)ethyl-N,N- diethylaniline hydrochloride and 4-amino-N-ethyl-N-(2-methoxyethyl)-m-toluidine di-p-toluenesulfonate.

In the case of negative-working silver halide emulsions, this development step produces a negative image. To produce a positive (or reversal) image, this step may be preceded by development with a non-chromogenic developing agent to develop exposed silver halide without producing a dye, followed by uniform fogging of the element to render unexposed silver halide developable. Alternatively, a direct-positive emulsion may be used to produce a positive image.

Development is followed by the usual steps of bleaching, fixing or bleach-fixing to remove silver and silver halide, as well as washing and drying steps.

Photographic examination

The methods of photographic examination used in the examples below were carried out as follows.

(i) Preparation of experimental photographic coatings

Each coupler of the invention was dissolved in half its weight in di-n-butyl phthalate with one and a half times its weight of cyclohexanone as a co-solvent and then dispersed in gelatin. The co-solvent was removed from the dispersion by continuous washing for 6 hours at 4°C and pH 6.0.

Experimental photographic coatings were prepared by coating a cellulose acetate film support with a photosensitive layer of a dispersion of the new coupler as above coated at a coverage of 1.93 millimoles/m², a silver bromoiodide emulsion at 0.81 Ag/m², and gelatin at 2.42 g/m². A topcoat of 0.89 g/m² gelatin was coated on the photosensitive layer. Bis-vinylsulfonylmethane was also incorporated into the photosensitive layer at a concentration of 1.75% by weight of the total gelatin in the package. The dried experimental coating was then slit and made into 35 mm x 30.48 cm test strips.

Couplers of the invention were also dispersed using ethyl acetate as an auxiliary solvent (which was subsequently removed by evaporation under reduced pressure) as well as in the complete absence of the main coupler solvent (NS dispersions) and then photographic coatings were prepared as described above.

(ii) Coupler stability and crystallinity measurement

The crystallinity of each coupler dispersion prepared for study was examined by spreading a few drops of the dispersion on a microscopic slide, placing a covering glass slide on top, and viewing the whole at a magnification of 1250x using differential interference contrast to improve the lighting conditions.

The crystallinity of the coupler in the film was determined primarily by visual inspection and by a deterioration of the sensitometric properties.

The stability of the coupler in the film was measured by incubating unexposed test strips for 24 hours at 21ºC and 50% relative humidity, followed by a dry incubation for one week at 49ºC. The strips were then exposed and developed as described below, and their sensitometric properties were compared with those of fresh test strips of the same coupler.

(iii) Sensitometric examination

The 35 mm test strips were exposed through a step wedge to a Neutral Density (ND) of 0 - 4.0 (0.2 ND step increments) using Daylight V, Wratten 35 and 38 A and 0.3 ND filters. The strips were developed using an automated deep tank process at 37.8ºC using the following standard process:

Color developer 2.5 minutes

bleach (FeIII/EDTA) 4 minutes

wash 2 minutes

fix 4 minutes

wash 2 minutes,

the solutions consisting of solutions as used in the C41 process described in the British Journal of Photography Annual 1977, pages 204 - 5, the color developing agent being 4-amino-3-methyl-N-ethyl-N-2-hydroxyethylaniline sulfate. The developed strips were then dried to give graduated yellow dye images.

In addition to the standard conditions given above, test strips were developed in a competitive process by adding 5.0 g/L citrazinic acid (CZA) to the color developer solution, adjusting the pH to 10.0 using sodium carbonate.

The step wedge densities of each test strip were measured using an automatic transmission densitometer of the type Macbeth TD504/Hewlett Packard 85. The minimum density (Dmin), the maximum density (Dmax), the contrast (γ) and the photographic speed (PS) were measured. The ratio of the contrast in the competing CZA process to the contrast in the standard process (γCZA/γSTD) is an indication of the reactivity of the coupler in the film.

Silver analyses (X-ray fluorescence) of the step wedges of the yellow dyes, produced by a standard process in which the bleaching step was omitted, enabled the recording of silver development curves. From these curves and the D/log E curves, dye density yield curves were generated for each individual coupler. In Figure 1 of the accompanying drawings, couplers 2 and 3 of the invention are compared with couplers 6 and 7 of the prior art.

(iv) Spectrophotometric examination

35 mm test strips were exposed through a 0-0.3 ND step wedge (0.1 increments) as indicated above, using daylight V, Wratten 35 and 38A filters and the correct ND filters to produce an optical density of approximately 1.0. The strips were developed under the standard conditions indicated above, after which samples were cut from the yellow dye image step with the density closest to 1.0. Visible absorption spectra (normalized to a density of 1.0) were obtained using a Pye Unicam SPS-100 spectrophotometer. The hues were expressed in terms of wavelength, corresponding to the maximum absorption peak (λ max) and half bandwidth (HBW) calculated from the spectrophotometric curves.

Extinction coefficients of the yellow dyes were determined from ethyl acetate solutions of the preformed dyes using an automatic UV/visible light spectrophotometer of the type Varian DM5 90/Apple II.

(v) Dye stability study

Spots were prepared from samples of the yellow dyes of density of approximately 1.0 as for spectrophotometric study, and their absorption spectra were measured as above.

In the case of the test to determine dark storage quality, the yellow dye samples were incubated in a dark oven for 1, 3 and 6 weeks at a constant temperature of 60ºC and 70% relative humidity. The spectrophotometric curves of the samples were then re-recorded and the degree of bleaching was determined as the fraction of the decrease in density at the absorption maximum (AD) relative to the original density before bleaching.

example 1

The dark/wet fading data of couplers (1) to (5) are given below and are compared with the reference compound (6), i.e. a conventional benzoylacetanilide with a coupling-off hydantoin group. Dark/moist bleaching compound (6 weeks) (comparison)

The structure of coupler 6 was as follows:

Here Et stands for ethyl and Bz for benzyl.

It can be seen that the dye images formed from all of the couplers (1) to (5) according to this invention have superior dark/wet stability compared to the prior art coupler (6).

Example 2

Table 1, with examples according to the invention (2) and (3) illustrates the superior Dmax and contrast values achieved in dye images from couplers according to the invention as compared to a currently conventional prior art pivaloylacetanilide coupler (7).

The dark/wet fade data for this set of couplers illustrate the superiority of the couplers of the invention (2) and (3) with a leaving phenolic group over a currently conventional benzoylacetanilide (6) with a leaving heterocyclic group.

The contrast ratios of this set illustrate the superior activity of the present benzoylacetanilides compared to the conventional pivaloylacetanilide (7). Table 1 Compound Contrast Contrast ratio D/W fading 6 weeks

Footnotes:

1) CZA stands for citrazinic acid.

2) A positive dye fade value means an increase in dye density.

While dyes prepared from couplers (2) and (3) show good fade and contrast ratio, the dye from coupler (6) shows acceptable Dmax, acceptable contrast and acceptable reactivity but poor dark/wet fade and the dye from coupler (7) shows acceptable dark/wet fade but low Dmax and low contrast.

Claims (8)

1. A silver halide color photographic element comprising a support having thereon at least one silver halide photographic emulsion layer and a non-diffusing yellow dye-forming para-R-oxybenzoylacetanilide coupler, said coupler being characterized by a combination of (a) a para-hydroxyphenylsulfonylphenoxy coupling-off group in the coupling position, (b) a chloro or trifluoromethyl group in the ortho position on the anilide moiety, and (c) a group on the anilide moiety selected from (i) an aliphatic hydrocarbon group bonded directly or through a linking group to the anilide moiety, said linking group being a carbainoyl (-CONH-), sulfonate (-O-SO₂-), phosphate (-O-PO₂-) or alkylene group, (ii) chlorine and (iii) trifluoromethyl; wherein the anilide moiety has no further substituents; wherein the coupler has at least one ballast group on at least one of the anilide and para-R-oxybenzoyl moieties; and wherein R is a non-substituted or substituted cyclic or non-cyclic aliphatic hydrocarbon group. 2. A silver halide color photographic element according to claim 1, wherein the non-diffusing yellow dye-forming coupler is represented by the following formula: where: R¹ represents an unsubstituted or substituted cyclic or non-cyclic aliphatic hydrocarbon group; Y is chlorine or trifluoromethyl; Z is halogen, trifluoromethyl or -L-R², where R² is an unsubstituted or substituted aliphatic hydrocarbon group, L is a direct bond or a carbamoyl (-CONH-), sulfonate (-O-So₂-), phosphate (-O-PO₂-) or alkylene group and at least one of the radicals R¹ and Z is a ballast group 3. A silver halide color photographic element according to claim 2, wherein z represents a ballast group and R¹ represents an alkyl group having 1 to 4 carbon atoms. 4. A silver halide color photographic element according to claim 2, wherein R¹ represents a ballast group. 5. A silver halide color photographic element according to claim 1, wherein the coupler corresponds to one of the following structural formulas: 6. A silver halide color photographic element according to any one of claims 1 to 5, comprising a support having thereon at least one red-sensitive silver halide emulsion layer having associated therewith a cyan dye-forming material, at least one green-sensitive silver halide emulsion layer having associated therewith a magenta dye-forming material, and at least one blue-sensitive silver halide emulsion layer having associated therewith the non-diffusing yellow dye-forming coupler. 7. A process for producing a dye image in an exposed silver halide color photographic element according to any one of claims 1 to 6, which comprises developing the silver halide color photographic element in a color photographic developer. 8. A yellow dye-forming benzoylacetanilide photographic color coupler according to any one of claims 1 to 5.