EP0491317A1

EP0491317A1 - Photographic coupler compositions and elements containing hydroxy benzoates

Info

Publication number: EP0491317A1
Application number: EP19910121505
Authority: EP
Inventors: Paul Barrett C/O Eastman Kodak Company Merkel; Edward C/O Eastman Kodak Company Schofield
Original assignee: Eastman Kodak Co
Current assignee: Eastman Kodak Co
Priority date: 1990-12-17
Filing date: 1991-12-16
Publication date: 1992-06-24
Also published as: JPH04294348A

Abstract

Photographic coupler compositions comprise a magenta dye-forming coupler and a hydroxy benzoate compound in an amount sufficient to increase the activity of the dye-forming coupler. The hydroxy benzoate compound is of the formula

wherein the COOR₁ substituent is located in the meta or para position with respect to the hydroxy group, R₁ is selected from the group consisting of straight chain and branched chain alkyl groups, alkenyl groups and alkylene groups, and halogen-substituted straight chain and branched chain alkyl, alkenyl and alkylene groups, each R₂ is a straight or branched chain alkyl or alkoxy group or a chlorine atom, and n is from 0 to 4, provided that the total number of carbon atoms in R₁ and all R₂'s is from about 7 to about 24.

Description

The present invention relates to photographic coupler compositions which comprise a magenta dye-forming coupler and a hydroxy benzoate compound which increases the activity of the dye-forming coupler. The invention also relates to silver halide color photographic materials including such coupler compositions.
It is well known in the color photography art that color images are produced by a colored dye which is formed by a coupling reaction between an oxidized product of an aromatic primary amine color developing agent and a coupler. Various types of cyan, magenta and yellow dye-forming couplers are well known for use in such coupling reactions. The couplers are often used in combination with one or more solvents and/or other additives. For example, the Thirtle et al U. S. Patent No. 2,835,579 discloses photographic emulsions comprising couplers in combination with alkylphenol or acylphenol coupler solvents. Similarly, Japanese Published Patent Application No. 61-075349 discloses photographic silver halide emulsion layers containing a coupler dissolved in a phenolic organic solvent having a high boiling point. The Aoki et al U. S. Patent No. 4,686,177 discloses silver halide color photographic materials containing a cyan coupler which may be dissolved in an organic solvent. The resulting solution is finely dispersed in water or an aqueous binder for incorporation in the photographic material. Aoki et al broadly disclose numerous organic solvents which may be employed including, among others, alcohols and phenols. The Konishiroku Photo Industry European Published Patent Application Nos. 137,722, 143,570 and 145,342 similarly disclose silver halide color photographic materials which include at least one magenta coupler and a non-color forming phenolic compound such as a phenolic high-boiling organic solvent. Japanese Published Patent Application No. 81-041098 discloses silver halide color photographic light sensitive materials prepared using cyan coupler compounds dispersed and emulsified in solvents having a boiling point greater than 200°C and saturated alcohols of the formula ROH wherein R is a 9 to 18 carbon containing saturated unbranched aliphatic group.
It is often desirable in color photography to provide the coupler compounds with improved coupler activity. As employed herein, the term improved coupler activity relates to the improved colorability of a coupler as indicated, for example, by the acceleration of the reaction of the coupler with the oxidized developer in forming the colored dye and/or by an increase in the color density of the resulting colored dye. For example, the Sasaki et al U. S. Patent No. 4,774,166 broadly discloses numerous compounds for use as coloration accelerators for couplers which result in a reduction in the photographic processing time. Sasaki et al disclose that preferred coloration accelerators comprise phenolic compounds, oxyalkylene compounds and hydroxy substituted, 5- to 7- membered heterocyclic ring compounds. Sasaki et al also broadly disclose the use of various high boiling point organic solvents in combination with the couplers, which solvents include, among others, phthalates, phosphates and benzoates. The Kimura et al U. S. Patent No. 4,551,442 also discloses silver halide photographic materials containing at least one cyan coupler and a phenolic compound which improves color image. The Snyder U. S. Patent No. 4,207,393 discloses compositions containing a coupler compound and a phenolic compound which acts as a contrast enhancer.
Many coupler compositions, however, are disadvantageous in that relatively large amounts of a coupler are required to provide satisfactory color density, the reaction rate of the coupler with the oxidized developer is unacceptably low, the coupler exhibits unacceptably high sensitivity to the pH of the developer solution and/or the like.
The problem to be solved by this invention is to provide coupler compositions of improved activity for use in color photographic materials and methods.
A more specific problem to be solved is to provide coupler compositions which exhibit improved coupler activity wherein improved coupler activity is indicated by an increased color density in a colored dye formed from the coupler composition. A further problem to be solved of the present invention to provide coupler compositions which exhibit improved coupler activity as indicated by an increase in the color density of the dye resulting from reaction of the coupler composition, without causing significant bathochromic hue shifts in the colored dye.
The present invention provides photographic coupler compositions which comprise a magenta dye-forming coupler and a hydroxy benzoate compound in an amount sufficient to increase the activity of the dye-forming coupler. In one embodiment there is provided a photographic coupler composition, comprising a magenta dye-forming coupler, and a hydroxy benzoate compound in an amount sufficient to increase the activity of the dye-forming coupler, the hydroxy benzoate compound being of the formula

wherein the COOR₁ substituent is located in the meta or para position with respect to the hydroxy group, R₁ is selected from the group consisting of straight chain and branched chain alkyl groups, straight chain and branched chain alkenyl groups and straight chain and branched chain alkylene groups, and halogen-substituted derivatives of said alkyl, alkenyl and alkylene groups, R₂ is selected from the group consisting of straight chain and branched chain alkyl groups, straight chain and branched chain alkoxy groups and a chlorine atom, and n is 0 or 1, provided that the total number of carbon atoms in R₁ and R₂ is from about 7 to about 24, and the magenta dye-forming coupler being of a formula selected from the following:

wherein
Ar is an unsubstituted aryl group or an aryl group substituted with one or more substituents selected from halogen atoms and cyano, alkylsulfonyl, arylsulfonyl, sulfamoyl, sulfonamido, carbamoyl, carbonamido, alkoxy, acyloxy, aryloxy, alkoxycarbonyl, aryloxycarbonyl, ureido, nitro, alkyl, and trifluoromethyl, or Ar is an aryl group substituted with a group which forms a link to a polymeric chain;
R¹ is a substituted or unsubstituted phenyl group and R² is selected from substituted and unsubstituted alkyl groups and substituted and unsubstituted phenyl groups, the R¹ and R² substituents being individually selected from halogen atoms, and alkyl, aryl, alkoxy, aryloxy, carbonamido, carbamoyl, sulfonamido, sulfamoyl, alkylsulfoxyl, arylsulfoxyl, alkylsulfonyl, arylsulfonyl, alkoxycarbonyl, aryloxycarbonyl, acyl, acyloxy, ureido, imido, carbamate, heterocyclic, cyano, trifluoromethyl, alkylthio, nitro, carboxyl and hydroxyl groups, provided that R¹ and R² each contain at least 6 carbon atoms or the R¹ and R² substituents individually comprise a group which forms a link to a polymeric chain;
R³ and R⁴ are individually selected from the group consisting of hydrogen, substituted and unsubstituted alkyl, substituted and unsubstituted phenyl, substituted and unsubstituted alkoxy, substituted and unsubstituted amino, substituted and unsubstituted anilino, substituted and unsubstituted acylamino, halogens and a group which links to a polymer, provided that the total number of carbon atoms contained in R³ and R⁴ is at least 6 if neither R³ nor R⁴ is a group which links to a polymer; and
X is hydrogen or a coupling-off group selected from the group consisting of halogens, alkoxy, aryloxy, alkylthio, arylthio, acyloxy, sulfonamido, carbonamido, arylazo, nitrogen-containing heterocyclic and imido groups. In another embodiment there is provided a color photographic element, comprising a silver halide emulsion and a coupler composition comprising a magenta dye-forming coupler and a hydroxy benzoate compound in an amount sufficient to increase the activity of the dye-forming coupler, the hydroxy benzoate compound being of the formula

wherein the COOR₁ substituent is located in the meta or para position with respect to the hydroxy group, R₁ is selected from the group consisting of straight chain and branched chain alkyl groups, straight chain and branched chain alkenyl groups and straight chain and branched chain alkylene groups, and halogen-substituted derivatives of said alkyl, alkenyl and alkylene groups, R₂ is selected from the group consisting of straight chain and branched chain alkyl groups, straight chain and branched chain alkoxy groups and a chlorine atom, and n is 0 or 1, provided that the total number of carbon atoms in R₁ and R₂ is from about 7 to about 24, and the magenta dye-forming coupler being of a formula selected from the following:

wherein
Ar is an unsubstituted aryl group or an aryl group substituted with one or more substituents selected from halogen atoms and cyano, alkylsulfonyl, arylsulfonyl, sulfamoyl, sulfonamido, carbamoyl, carbonamido, alkoxy, acyloxy, aryloxy, alkoxycarbonyl, aryloxycarbonyl, ureido, nitro, alkyl, and trifluoromethyl, or Ar is an aryl group substituted with a group which forms a link to a polymeric chain;
R¹ is a substituted or unsubstituted phenyl group and R² is selected from substituted and unsubstituted alkyl groups and substituted and unsubstituted phenyl groups, the R¹ and R² substituents being individually selected from halogen atoms, and alkyl, aryl, alkoxy, aryloxy, carbonamido, carbamoyl, sulfonamido, sulfamoyl, alkylsulfoxyl, arylsulfoxyl, alkylsulfonyl, arylsulfonyl, alkoxycarbonyl, aryloxycarbonyl, acyl, acyloxy, ureido, imido, carbamate, heterocyclic, cyano, trifluoromethyl, alkylthio, nitro, carboxyl and hydroxyl groups, provided that R¹ and R² each contain at least 6 carbon atoms or the R¹ and R² substituents individually comprise a group which forms a link to a polymeric chain;
R³ and R⁴ are individually selected from the group consisting of hydrogen, substituted and unsubstituted alkyl, substituted and unsubstituted phenyl, substituted and unsubstituted alkoxy, substituted and unsubstituted amino, substituted and unsubstituted anilino, substituted and unsubstituted acylamino, halogens and a group which links to a polymer, provided that the total number of carbon atoms contained in R³ and R⁴ is at least 6 if neither R³ nor R⁴ is a group which links to a polymer; and
X is hydrogen or a coupling-off group selected from the group consisting of halogens, alkoxy, aryloxy, alkylthio, arylthio, acyloxy, sulfonamido, carbonamido, arylazo, nitrogen-containing heterocyclic and imido groups.
It has been discovered that the hydroxy benzoate compound employed in the coupler compositions of the present invention provides the magenta dye-forming coupler with increased activity as indicated by an increase in the color density of the colored dye formed therefrom, particularly without causing significant bathochromic hue shifts in the colored dye. Thus, the hydroxy benzoate compound is employed in combination with the magenta dye-forming coupler in order to increase the dye-forming coupler's activity. The coupler compositions of the present invention are therefore suitable for use in improved silver halide color photographic materials and in improved methods for the formation of color images.
The hydroxy benzoate compounds which are employed in the coupler compositions of the present invention may serve as solvents for the coupler compounds and/or may be used as non-solvent additives. It is important that the hydroxy benzoate compounds employed in the present invention contain sufficient ballast to minimize their water solubility, volatility and diffusivity. Hydroxy benzoate compounds suitable for use in the coupler compositions of the present invention are of the formula

wherein the COOR₁ substituent is located in the meta or para position with respect to the hydroxy group, R₁ is selected from the group consisting of straight chain and branched chain alkyl groups, alkenyl groups and alkylene groups, and halogen-substituted straight chain and branched chain alkyl, alkenyl and alkylene groups, each R₂ is a straight or branched chain alkyl or alkoxy group or chlorine atom, and n is from 0 to 4, provided that the total number of carbon atoms in R₁ and all R₂'s is from about 7 to about 24.
As noted above, the COOR₁ substituent may be located in the meta or para position with respect to the hydroxy group. In a preferred embodiment, the COOR₁ substituent is located in the para position with respect to the hydroxy group. In an additionally preferred embodiment, R₁ comprises a straight or branched chain alkyl group and contains at least 8 carbon atoms. As also set forth above, the hydroxy benzoate compounds may contain from 0 to 4 of the R₂ substituents. In preferred embodiments, the compounds contain no R₂ substituents (n is zero) or a single R₂ substituent (n is 1). In a further preferred embodiment, the total number of carbon atoms in R₁ and all of the R₂ substituents is from about 8 to about 18. As will be set forth in detail in the examples, hydroxy benzoate compounds particularly suitable for use in the compositions and methods of the present invention include, but are not limited to, 2-ethylhexyl-p-hydroxybenzoate, nonyl-p-hydroxybenzoate and dodecyl-p-hydroxybenzoate. Additional useful hydroxy benzoates include, but are not limited to, the following:
As noted above, the hydroxy benzoate compound employed in the coupler compositions of the present invention may act as a solvent for the dye-forming coupler. One or more additional organic solvents for the coupler compound may also be employed in the compositions of the present invention. Generally, conventional organic coupler solvents are known in the art and may be employed when the hydroxy benzoate compound of the present invention is used in an additive amount which is not sufficient to result in a solution of the coupler compound. Examples of conventional organic solvents which may be used in the present compositions are described in the Examples set forth below.
The hydroxy benzoate compound is employed in the coupler compositions of the present invention in an amount sufficient to increase the activity of the dye-forming coupler. In most applications, it is preferred that the dye-forming coupler and the hydroxy benzoate compound are employed in a weight ratio of from about 1:0.1 to about 1:10 in order to effect an increase in the activity of the dye-forming coupler.
The dye-forming coupler included in the present coupler compositions comprises a magenta dye-forming coupler. Couplers which form magenta dyes upon reaction with oxidized color developing agents are well known in the art and are described in such representative patents and publications as: U. S. Patents Nos. 2,600,788; 2,369,489; 1,969,479; 2,311,082; 3,061,432; 3,725,067; 4,120,723; 4,500,630; 2,343,703; 2,311,082; 3,152,896; 3,519,429; 3,062,653; 2,908,573; 4,774,172; 4,443,536; 3,935,015; 4,540,654; 4,581,326; European Patent Applications 284,239; 284,240; 240,852; 170,164; 177,765 and "Farbkupplereine Literaturübersicht," published in Agfa Mitteilungen, Band III, pp. 126-156 (1961), the disclosures of which are incorporated herein by reference.
Preferred magenta dye-forming couplers comprise pyrazolone compounds of the general formulae:

pyrazolotriazole compounds of the general formulae:

and pyrazolobenzimidazoles of the formula:

wherein
Ar is an unsubstituted aryl group or an aryl group (including pyridyl) substituted with one or more substituents selected from halogen atoms and cyano, alkylsulfonyl, arylsulfonyl, sulfamoyl, sulfonamido, carbamoyl, carbonamido, alkoxy, acyloxy, aryloxy, alkoxycarbonyl, aryloxycarbonyl, ureido, nitro, alkyl, and trifluoromethyl, or Ar is an aryl group substituted with a group which forms a link to a polymeric chain;
R¹ is a substituted or unsubstituted phenyl group and R² is a substituted or unsubstituted alkyl or phenyl group, the R¹ and R² substituents being individually selected from halogen atoms, and alkyl, aryl, alkoxy, aryloxy, carbonamido, carbamoyl, sulfonamido, sulfamoyl, alkylsulfoxyl, arylsulfoxyl, alkylsulfonyl, arylsulfonyl, alkoxycarbonyl, aryloxycarbonyl, acyl, acyloxy, ureido, imido, carbamate, heterocyclic, cyano, trifluoromethyl, alkylthio, nitro, carboxyl and hydroxyl groups, provided that R¹ and R² each contain at least 6 carbon atoms or the R¹ and R² substituents may individually comprise a group which forms a link to a polymeric chain;
R³ and R⁴ are individually selected from the group consisting of hydrogen, substituted and unsubstituted alkyl, substituted and unsubstituted phenyl, substituted and unsubstituted alkoxy, substituted and unsubstituted amino, substituted and unsubstituted anilino, substituted and unsubstituted acylamino, halogens and a group which links to a polymer, provided that the total number of carbon atoms contained in R³ and R⁴ is at least 6 if neither R³ nor R⁴ is a group which links to a polymer; and
X is hydrogen or a coupling-off group selected from the group consisting of halogens, alkoxy, aryloxy, alkylthio, arylthio, acyloxy, sulfonamido, carbonamido, arylazo, nitrogen-containing heterocyclic and imido groups. Coupling-off groups are well known to those skilled in the photographic art. Generally, such groups determine the equivalency of the coupler and modify the reactivity of the coupler. Coupling-off groups can also advantageously effect the layer in which the coupler is coated or other layers in the photographic material by performing, after release from the coupler, such functions as development inhibition, bleach acceleration, color correction, development acceleration and the like. Representative coupling-off groups include, as noted above, halogens (for example, chloro), alkoxy, aryloxy, alkyl thio, aryl thio, acyloxy, sulfonamido, carbonamido, arylazo, nitrogen-containing heterocyclic groups such as pyrazolyl and imidazolyl, and imido groups such as succinimido and hydantoinyl groups. Except for the halogens, these groups may be substituted if desired. Coupling-off groups are described in further detail in: U. S. Patents Nos. 2,355,169; 3,227,551; 3,432,521; 3,476,563; 3,617,291; 3,880,661; 4,052,212 and 4,134,766, and in British Patent References Nos. 1,466,728; 1,531,927; 1,533,039; 2,006,755A and 2,017,704A, the disclosures of which are incorporated herein by reference.
As is well known in the photographic art, a coupler compound should be nondiffusible when incorporated in a photographic element. That is, the coupler compound should be of such a molecular size and configuration that it will exhibit substantially no diffusion from the layer in which it is coated.
To achieve this result, the total number of carbon atoms contained in R¹, or R², or R³ and R⁴ combined should be at least 6. Preferably, R¹, or R², or R³ and R⁴ combined contain from 6 to about 30 carbon atoms. Alternatively, R¹, or R², or R³ or R⁴ may serve as a link to or form part of a polymeric chain.
In a preferred embodiment, the magenta dye-forming coupler is of the formula M-1 and Ar is of the formula

wherein R⁵ is selected from the group consisting of halogen atoms and cyano, alkylsulfonyl, arylsulfonyl, sulfamoyl, sulfonamido, carbamoyl, carbonamido, ureido, alkoxycarbonyl, aryloxycarbonyl, acyloxy, alkoxy, aryloxy, nitro and trifluoromethyl groups. It is further preferred that when the magenta dye-forming coupler is of the formula M-1, R¹ is of the formula

wherein
p is from zero to 2 and each R⁶ is in a meta or para position with respect to R⁷;
each R⁶ is individually selected from the group consisting of halogen atoms and alkyl, alkoxy, aryloxy, carbonamido, carbamoyl, sulfonamido, sulfamoyl, alkylsulfoxyl, arylsulfoxyl, alkylsulfonyl, arylsulfonyl, alkoxycarbonyl, aryloxycarbonyl, acyloxy, ureido, imido, carbamate, heterocyclic, cyano, nitro, acyl, trifluoromethyl, alkylthio and carboxyl groups; and
R⁷ is selected from the group consisting of hydrogen, halogen atoms and alkyl, alkoxy, aryloxy alkylthio, carbonamido, carbamoyl, sulfonamido, sulfamoyl, alkylsulfonyl, arylsulfonyl, alkoxycarbonyl, acyloxy, acyl, cyano, nitro and trifluoromethyl groups. Preferably, R⁷ is a chlorine atom or an alkoxy group. In another preferred embodiment, advantageous speed/fog positions can be achieved by using the above described hydroxy benzoate compounds with a coupler according to formula M-3 that is linked to a polymeric chain.
Suitable magenta dye-forming couplers for use in the compositions and methods of the present invention include, but are not limited to, the following compounds (m-i) - (m-xv):
The photographic coupler compositions according to the present invention are employed in color photographic materials in a manner well known in the color photographic art. For example, a supporting substrate is coated with a silver halide emulsion and the coupler composition of the present invention comprising a magenta dye-forming coupler and a hydroxy benzoate compound in an amount sufficient to increase the activity of the dye-forming coupler. The photographic material is then imagewise exposed in a manner well known in the color photography art followed by development with an aromatic primary amine developer. As is well known in the art, the oxidation product of the aromatic primary amine developer reacts with the coupler compound to form the colored dye images.
The compositions and methods of the present invention are demonstrated by the following Examples in which references are to parts by weight unless otherwise specified. Additionally, the following hydroxy benzoate compounds (S-I - S-III) and conventional coupler solvents (S-IV - S-VII) were employed in the Examples:

S-I:: 2-ethylhexyl-p-hydroxybenzoate (invention)
S-II:: nonyl-p-hydroxybenzoate (invention)
S-III:: dodecyl-p-hydroxybenzoate (invention)
S-IV:: mixed tritolyl phosphates (comparative)
S-V:: di-n-butyl phthalate (comparative)
S-VI:: p-dodecyhlphenol (comparative)
S-VII:: 2,4-di-t-pentylphenol (comparative)

EXAMPLE 1

Coupler compositions comprising emulsion dispersions of the coupler compound (m-i) as set forth above were prepared using hydroxy benzoate compounds according to the present invention as solvents and using conventional coupler solvents for comparison purposes as set forth in Table I. Specifically, an oil phase was prepared by warming a mixture of 3.4g of coupler compound (m-i), 1.7g of the respective coupler solvent and 10.2g of an auxiliary solvent comprising 2-(2-butoxyethoxy) ethylacetate until dissolution was complete. The weight ratio of coupler compound to the non-auxiliary solvent was 1:0.5. The resulting solution was added to an aqueous solution containing 18.13g of a 12.5 weight percent aqueous gelatin, 2.27g of a 10% aqueous Alkanol XC solution and 2.08g of water. The resulting mixture was then passed through a colloid mill three times to disperse the oil phase and the resulting dispersion was chilled, noodled and washed for four hours at 40°C to remove the auxiliary solvent. The resulting dispersed coupler composition was then coated on a cellulose acetate butyrate support at a level of 1.5 x 10⁻⁴ moles/ft² (108 mg/ft²) together with a sensitized silver bromoiodide emulsion (approximately 0.55 µ, 12% iodide) in the following format:

Hardened film strips of the resulting product were exposed (1/25 sec, 1B sensitometer) through a step tablet and then subjected to The Kodak Flexicolor commercial development process. After processing, the status M green densities vs exposure were measured for each film strip using a densitometer. Spectral absorption maxima (λmax) at densities of approximately 1.0 were measured using a spectrophotometer. The contrast or photographic gamma was measured on the straight line portion of the density v. exposure curve. The results are set forth in Table I.

TABLE I

Coupler Solvent	Gamma	λmax (nm)
S-I (invention)	2.50	556.1
S-II (invention)	2.51	556.3
S-III (invention)	2.77	556.7
S-IV (comparative)	1.72	555.7
S-V (comparative)	1.94	556.1
S-VI (comparative)	2.73	557.3

From the results set forth in Table I, it is apparent that the use of the hydroxy benzoate compounds as coupler solvents according to the present invention results in improved color density as measured by the gamma value, without causing significant bathochromic hue shifts.

EXAMPLE 2

Coupler compositions comprising emulsion dispersions of the coupler compound (m-ii) as set forth above were prepared using a hydroxy benzoate compound according to the present invention and using conventional coupler solvents for comparison purposes as set forth in Table II. Specifically, an oil phase comprising 0.90g of the coupler compound (m-ii), 0.90g of the respective coupler solvent and 2.70g of the auxiliary solvent described in Example 1 was added to an aqueous phase comprising 7.20g of a 12.5% aqueous gelatin, 0.90g of a 10% aqueous Alkanol XC solution and 2.40g of water. The weight ratio of coupler compound to the non-auxiliary coupler solvent was 1:1. The mixture was passed through a colloid mill to disperse the oil phase, and the resulting dispersion was then coated at a level of 1.0 x 10⁻⁴ moles/ft² (65.7 mg/ft²) with 84.2 mg/ft² of the silver bromoiodide emulsion described in Example 1 in the following format:

Hardened film strips of the resulting products were processed in accordance with the methods disclosed in Example 1. Additionally, the gamma values and the λmax values of the processed products were obtained by the procedures set forth in Example 1. The results of these measurements are set forth in Table II. TABLE II

Coupler Solvent Gamma λmax (nm)

S-I (invention) 1.00 564.6

S-IV (comparative) 0.58 556.3

S-V (comparative) 0.69 556.2

S-VI (comparative) 1.37 569.0
The results set forth in Table II demonstrate that the composition which included a hydroxy benzoate compound according to the present invention exhibited an increase in gamma value as compared with the use of comparative solvents S-IV and S-V. Additionally, the coupler composition according to the present invention including the hydroxy benzoate compound exhibited a significantly lower bathochromic hue shift as indicated by λmax as compared with the use of the conventional coupler solvent S-VI. Thus, the coupler composition according to the present invention exhibited a desirable combination of properties, namely, improved color density with reduced hue shift.

EXAMPLE 3

In the manner set forth in Example 1, coupler compositions comprising emulsion dispersions of coupler compound (m-iii) as set forth above were prepared using a hydroxy benzoate compound according to the present invention and using conventional coupler solvents for comparison purposes as described in Table III. The coupler dispersion was coated on the support at a level of 1.0 x 10⁻⁴ mole/ft² together with an equal weight of coupler solvent. The resulting film strips were processed in the manner generally described in Example 1 and the respective gamma values were determined. The gamma values for the respective solvents are set forth in Table III. TABLE III

Coupler Solvent Gamma

S-I (invention) 1.60

S-IV (comparison) 1.32

S-V (comparison) 1.06

S-VI (comparison) 1.25
The results set forth in Table III demonstrate that the use of a hydroxy benzoate compound as a coupler solvent in accordance with the present invention provides a desirable increase in the gamma value as compared with the use of conventional coupler solvents. This improvement in gamma value provides improved color images and allows reductions in the amounts of couplers and/or silver halide compositions which must be employed in developing processes.

EXAMPLE 4

In this example, coupler compositions comprising emulsion dispersions of the polymeric coupler compound (m-v) as set forth above were prepared using a hydroxy benzoate compound according to the present invention and using conventional coupler solvents for comparison purposes as described in Table IV. Specifically, dispersions of the coupler compound were prepared by milling 3.0g of the respective coupler solvent and 1.1g of ethylacetate with 15 ml of a 12.5% aqueous gelatin, 1.9 ml of a 10% aqueous Alkanol XC solution and 9.1 ml of water. Each of the respective coupler solvent dispersions were combined with a latex dispersion of the coupler compound (m-v) to provide a weight ratio of coupler compound to solvent of 1:0.5. The resulting mixture was stirred for three hours at 40°C to permit loading of the coupler solvent into the latex. The coupler solvent-loaded latex dispersions of polymeric coupler compounds (m-v) were coated at a level of 1.5 x 10⁻⁴ moles/ft² together with the silver bromoiodide emulsion described in Example 1 in the following format:
Hardened film samples of the resulting product were processed in accordance with the procedures in Example 1. The gamma value and λmax for each sample were also determined in accordance with the procedures described in Example 1. The results of these measurements are set forth in Table IV. TABLE IV

Coupler Solvent Gamma λmax

S-I 2.18 560

S-IV 1.28 559

S-V 1.14 559

S-VI 1.81 561
The results set forth in Table IV demonstrate that the coupler compositions according to the present invention including a hydroxy benzoate compound exhibited significantly improved color density as measured by gamma without a significant hue shift as indicated by λmax.

EXAMPLE 5

In this example, coupler compositions comprising emulsion dispersions of the polymeric coupler compound (m-vi) as set forth above were prepared using a hydroxy benzoate compound according to the present invention and using conventional coupler solvents for comparison purposes as described in Table V. The dispersions were prepared following the procedures described in Example 4. The procedures described in Example 4 were also followed in producing hardened film strips. The coupler emulsion was coated at a level of 1.0 x 10⁻⁴ mole/ft². The processing and measurement procedures described in Example 1 were followed in order to determine the gamma and λmax values. The results of the measurements are set forth in Table V. TABLE V

Coupler Solvent Gamma λmax

S-I 3.50 553

S-IV 2.40 552

S-V 2.42 553

S-VI 3.30 558
The results set forth in Table V demonstrate that the coupler composition according to the present invention containing a hydroxy benzoate compound exhibited an advantageous combination of high gamma and low λmax values, indicating that the compositions provided improved color density and a low bathochromic hue shift.

EXAMPLE 6

In this example, additional coupler compositions comprising emulsion dispersions of the polymeric coupler compound (m-iv) as set forth above were prepared using a hydroxy benzoate compound according to the present invention and using conventional coupler solvents for comparison purposes as described in Table VI. Samples of the polymeric coupler compound (m-iv) were prepared using emulsion polymerization techniques or solution polymerization techniques as indicated in Table VI. The general procedures of Example 4 were followed in preparing the coupler dispersions and in preparing hardened film strips of the coupler dispersions. Additionally, the hardened strips were then processed and subjected to measurement of Dmax and gamma values in accordance with the procedures of Example 1. The results of these measurements are also set forth in Table VI.

TABLE VI

Polymeric Coupler	Coupler Solvent	Dmax	Gamma
emulsion	S-I (invention)	2.66	1.52
emulsion	S-IV (comparative)	1.38	0.87
emulsion	S-VII (comparative)	1.44	0.85
emulsion	none	1.13	0.79
solution	S-I (invention)	3.60	2.92
solution	S-IV (comparative)	2.42	2.00
solution	S-VII (comparative)	2.40	1.91
solution	none	2.28	2.04

The results set forth in Table VI demonstrate that the coupler compositions according to the present invention containing a hydroxy benzoate compound exhibit improved color density as indicated by Dmax and gamma, as compared with the coupler compositions containing no coupler solvent, and as compared with the coupler compositions containing conventional coupler solvents.
Similar coupler compositions containing additional hydroxy benzoate compounds according to the present invention were used to prepare color films which exhibited similar improvements in gamma values with little or no significant bathochromic hue shifts in the resulting color dyes.
This invention provides magenta dye-forming coupler compositions with high activity.

Claims

A photographic coupler composition, comprising a magenta dye-forming coupler, and a hydroxy benzoate compound in an amount sufficient to increase the activity of the dye-forming coupler, the hydroxy benzoate compound being of the formula
wherein the COOR₁ substituent is located in the meta or para position with respect to the hydroxy group, R₁ is selected from the group consisting of straight chain and branched chain alkyl groups, straight chain and branched chain alkenyl groups and straight chain and branched chain alkylene groups, and halogen-substituted derivatives of said alkyl, alkenyl and alkylene groups, R₂ is selected from the group consisting of straight chain and branched chain alkyl groups, straight chain and branched chain alkoxy groups and a chlorine atom, and n is 0 or 1, provided that the total number of carbon atoms in R₁ and R₂ is from about 7 to about 24, and the magenta dye-forming coupler being of a formula selected from the following:

wherein
Ar is an unsubstituted aryl group or an aryl group substituted with one or more substituents selected from halogen atoms and cyano, alkylsulfonyl, arylsulfonyl, sulfamoyl, sulfonamido, carbamoyl, carbonamido, alkoxy, acyloxy, aryloxy, alkoxycarbonyl, aryloxycarbonyl, ureido, nitro, alkyl, and trifluoromethyl, or Ar is an aryl group substituted with a group which forms a link to a polymeric chain;
R¹ is a substituted or unsubstituted phenyl group and R² is selected from substituted and unsubstituted alkyl groups and substituted and unsubstituted phenyl groups, the R¹ and R² substituents being individually selected from halogen atoms, and alkyl, aryl, alkoxy, aryloxy, carbonamido, carbamoyl, sulfonamido, sulfamoyl, alkylsulfoxyl, arylsulfoxyl, alkylsulfonyl, arylsulfonyl, alkoxycarbonyl, aryloxycarbonyl, acyl, acyloxy, ureido, imido, carbamate, heterocyclic, cyano, trifluoromethyl, alkylthio, nitro, carboxyl and hydroxyl groups, provided that R¹ and R² each contain at least 6 carbon atoms or the R¹ and R² substituents individually comprise a group which forms a link to a polymeric chain;
R³ and R⁴ are individually selected from the group consisting of hydrogen, substituted and unsubstituted alkyl, substituted and unsubstituted phenyl, substituted and unsubstituted alkoxy, substituted and unsubstituted amino, substituted and unsubstituted anilino, substituted and unsubstituted acylamino, halogens and a group which links to a polymer, provided that the total number of carbon atoms contained in R³ and R⁴ is at least 6 if neither R³ nor R⁴ is a group which links to a polymer; and
X is hydrogen or a coupling-off group selected from the group consisting of halogens, alkoxy, aryloxy, alkylthio, arylthio, acyloxy, sulfonamido, carbonamido, arylazo, nitrogen-containing heterocyclic and imido groups.
A color photographic element, comprising a silver halide emulsion and a coupler composition comprising a magenta dye-forming coupler and a hydroxy benzoate compound in an amount sufficient to increase the activity of the dye-forming coupler, the hydroxy benzoate compound being of the formula
wherein the COOR₁ substituent is located in the meta or para position with respect to the hydroxy group, R₁ is selected from the group consisting of straight chain and branched chain alkyl groups, straight chain and branched chain alkenyl groups and straight chain and branched chain alkylene groups, and halogen-substituted derivatives of said alkyl, alkenyl and alkylene groups, R₂ is selected from the group consisting of straight chain and branched chain alkyl groups, straight chain and branched chain alkoxy groups and a chlorine atom, and n is 0 or 1, provided that the total number of carbon atoms in R₁ and R₂ is from about 7 to about 24, and the magenta dye-forming coupler being of a formula selected from the following:

wherein
Ar is an unsubstituted aryl group or an aryl group substituted with one or more substituents selected from halogen atoms and cyano, alkylsulfonyl, arylsulfonyl, sulfamoyl, sulfonamido, carbamoyl, carbonamido, alkoxy, acyloxy, aryloxy, alkoxycarbonyl, aryloxycarbonyl, ureido, nitro, alkyl, and trifluoromethyl, or Ar is an aryl group substituted with a group which forms a link to a polymeric chain;
R¹ is a substituted or unsubstituted phenyl group and R² is selected from substituted and unsubstituted alkyl groups and substituted and unsubstituted phenyl groups, the R¹ and R² substituents being individually selected from halogen atoms, and alkyl, aryl, alkoxy, aryloxy, carbonamido, carbamoyl, sulfonamido, sulfamoyl, alkylsulfoxyl, arylsulfoxyl, alkylsulfonyl, arylsulfonyl, alkoxycarbonyl, aryloxycarbonyl, acyl, acyloxy, ureido, imido, carbamate, heterocyclic, cyano, trifluoromethyl, alkylthio, nitro, carboxyl and hydroxyl groups, provided that R¹ and R² each contain at least 6 carbon atoms or the R¹ and R² substituents individually comprise a group which forms a link to a polymeric chain;
R³ and R⁴ are individually selected from the group consisting of hydrogen, substituted and unsubstituted alkyl, substituted and unsubstituted phenyl, substituted and unsubstituted alkoxy, substituted and unsubstituted amino, substituted and unsubstituted anilino, substituted and unsubstituted acylamino, halogens and a group which links to a polymer, provided that the total number of carbon atoms contained in R³ and R⁴ is at least 6 if neither R³ nor R⁴ is a group which links to a polymer; and
X is hydrogen or a coupling-off group selected from the group consisting of halogens, alkoxy, aryloxy, alkylthio, arylthio, acyloxy, sulfonamido, carbonamido, arylazo, nitrogen-containing heterocyclic and imido groups.
A photographic coupler composition as defined by claim 1, wherein the COOR₁ substituent is located in the meta position with respect to the hydroxy group.
A photographic coupler composition as defined by claim 1, wherein the COOR₁ substituent is located in the para position with respect to the hydroxy group.
A photographic coupler composition as defined by claim 1, wherein R₁ is a straight or branched chain alkyl group.
A photographic coupler composition as defined by claim 5, wherein n is zero.
A photographic coupler composition as defined by claim 5, wherein n is at least 1.
A photographic coupler composition as defined by claim 1, wherein the total number of carbon atoms in R₁ and R₂ is from about 8 to about 18.
A photographic coupler composition as defined by claim 1, wherein the magenta dye-forming coupler is of the formula M-1 and wherein Ar is of the formula
wherein R⁵ is selected from the group consisting of halogen atoms and cyano, alkylsulfonyl, arylsulfonyl, sulfamoyl, sulfonamido, carbamoyl, carbonamido, ureido, alkoxycarbonyl, aryloxycarbonyl, acyloxy, alkoxy, aryloxy, nitro and trifluoromethyl groups.
A photographic coupler composition as defined by claim 1, wherein the magenta dye-forming coupler is of the formula M-1 and wherein R¹ is of the formula
wherein
p is from zero to 2 and each R⁶ is in a meta or para position with respect to R⁷;
each R⁶ is individually selected from the group consisting of halogen atoms and alkyl, alkoxy, aryloxy, carbonamido, carbamoyl, sulfonamido, sulfamoyl, alkylsulfoxyl, arylsulfoxyl, alkylsulfonyl, arylsulfonyl, alkoxycarbonyl, aryloxycarbonyl, acyloxy, ureido, imido, carbamate, heterocyclic, cyano, nitro, acyl, trifluoromethyl, alkylthio and carboxyl groups; and
R⁷ is selected from the group consisting of hydrogen, halogen atoms and alkyl, alkoxy, aryloxy alkylthio, carbonamido, carbamoyl, sulfonamido, sulfamoyl, alkylsulfonyl, arylsulfonyl, alkoxycarbonyl, acyloxy, acyl, cyano, nitro and trifluoromethyl groups.
A photographic coupler composition as defined by claim 10, wherein R⁷ is a chlorine atom or an alkoxy group.
A photographic coupler composition as defined by claim 1, wherein the magenta dye-forming coupler is of the formula M-1 and R¹ contains from 6 to about 30 carbon atoms.
A photographic coupler composition as defined by claim 1, wherein the magenta dye-forming coupler is of the formula M-2 and R² contains from 6 to about 30 carbon atoms.
A photographic coupler composition as defined by claim 1, wherein the magenta dye-forming coupler is of a formula selected from M-3 - M-5 and wherein the total number of carbon atoms contained in R³ and R⁴ is from 6 to about 30.
A photographic coupler composition as defined by claim 1, wherein the dye-forming coupler and the hydroxy benzoate compound are included in a weight ratio of from about 1:0.1 to about 1:10.
A photographic coupler composition as defined by claim 1, wherein the composition further includes a third component comprising an organic solvent.
A method for increasing the activity of a magenta dye-forming coupler in a color photographic developing process, comprising providing the dye-forming coupler in a photographic layer in combination with a hydroxy benzoate compound, the hydroxy benzoate compound being included in an amount sufficient to increase the activity of the dye-forming coupler and being of the formula
wherein the COOR₁ substituent is located in the meta or para position with respect to the hydroxy group, R₁ is selected from the group consisting of straight chain and branched chain alkyl groups, straight chain and branched chain alkenyl groups and straight chain and branched chain alkylene groups, and halogen-substituted derivatives of said alkyl, alkenyl and alkylene groups, R₂ is selected from the group consisting of straight chain and branched chain alkyl groups, straight chain and branched chain alkoxy groups and a chlorine atom, and n is 0 or 1, provided that the total number of carbon atoms in R₁ and R₂ is from about 7 to about 24, and the magenta dye-forming coupler being of a formula selected from the following:

wherein
Ar is an unsubstituted aryl group or an aryl group substituted with one or more substituents selected from halogen atoms and cyano, alkylsulfonyl, arylsulfonyl, sulfamoyl, sulfonamido, carbamoyl, carbonamido, alkoxy, acyloxy, aryloxy, alkoxycarbonyl, aryloxycarbonyl, ureido, nitro, alkyl, and trifluoromethyl, or Ar is an aryl group substituted with a group which forms a link to a polymeric chain;
R¹ is a substituted or unsubstituted phenyl group and R² is selected from substituted and unsubstituted alkyl groups and substituted and unsubstituted phenyl groups, the R¹ and R² substituents being individually selected from halogen atoms, and alkyl, aryl, alkoxy, aryloxy, carbonamido, carbamoyl, sulfonamido, sulfamoyl, alkylsulfoxyl, arylsulfoxyl, alkylsulfonyl, arylsulfonyl, alkoxycarbonyl, aryloxycarbonyl, acyl, acyloxy, ureido, imido, carbamate, heterocyclic, cyano, trifluoromethyl, alkylthio, nitro, carboxyl and hydroxyl groups, provided that R¹ and R² each contain at least 6 carbon atoms or the R¹ and R² substituents individually comprise a group which forms a link to a polymeric chain;
R³ and R⁴ are individually selected from the group consisting of hydrogen, substituted and unsubstituted alkyl, substituted and unsubstituted phenyl, substituted and unsubstituted alkoxy, substituted and unsubstituted amino, substituted and unsubstituted anilino, substituted and unsubstituted acylamino, halogens and a group which links to a polymer, provided that the total number of carbon atoms contained in R³ and R⁴ is at least 6 if neither R³ nor R⁴ is a group which links to a polymer; and
X is hydrogen or a coupling-off group selected from the group consisting of halogens, alkoxy, aryloxy, alkylthio, arylthio, acyloxy, sulfonamido, carbonamido, arylazo, nitrogen-containing heterocyclic and imido groups.
A method for the formation of color images, comprising (A) imagewise exposing a photographic layer, and (B) developing the exposed image, wherein the photographic layer comprises a silver halide emulsion and a coupler composition comprising (i) a magenta dye-forming coupler, and (ii) a hydroxy benzoate compound in an amount sufficient to increase the activity of the dye-forming coupler, the hydroxy benzoate compound being of the formula
wherein the COOR₁ substituent is located in the meta or para position with respect to the hydroxy group, R₁ is selected from the group consisting of straight chain and branched chain alkyl groups, straight chain and branched chain alkenyl groups and straight chain and branched chain alkylene groups, and halogen-substituted derivatives of said alkyl, alkenyl and alkylene groups, R₂ is selected from the group consisting of straight chain and branched chain alkyl groups, straight chain and branched chain alkoxy groups and a chlorine atom, and n is 0 or 1, provided that the total number of carbon atoms in R₁ and R₂ is from about 7 to about 24, and the magenta dye-forming coupler being of a formula selected from the following:

wherein
Ar is an unsubstituted aryl group or an aryl group substituted with one or more substituents selected from halogen atoms and cyano, alkylsulfonyl, arylsulfonyl, sulfamoyl, sulfonamido, carbamoyl, carbonamido, alkoxy, acyloxy, aryloxy, alkoxycarbonyl, aryloxycarbonyl, ureido, nitro, alkyl, and trifluoromethyl, or Ar is an aryl group substituted with a group which forms a link to a polymeric chain;
R¹ is a substituted or unsubstituted phenyl group and R² is selected from substituted and unsubstituted alkyl groups and substituted and unsubstituted phenyl groups, the R¹ and R² substituents being individually selected from halogen atoms, and alkyl, aryl, alkoxy, aryloxy, carbonamido, carbamoyl, sulfonamido, sulfamoyl, alkylsulfoxyl, arylsulfoxyl, alkylsulfonyl, arylsulfonyl, alkoxycarbonyl, aryloxycarbonyl, acyl, acyloxy, ureido, imido, carbamate, heterocyclic, cyano, trifluoromethyl, alkylthio, nitro, carboxyl and hydroxyl groups, provided that R¹ and R² each contain at least 6 carbon atoms or the R¹ and R² substituents individually comprise a group which forms a link to a polymeric chain;
R³ and R⁴ are individually selected from the group consisting of hydrogen, substituted and unsubstituted alkyl, substituted and unsubstituted phenyl, substituted and unsubstituted alkoxy, substituted and unsubstituted amino, substituted and unsubstituted anilino, substituted and unsubstituted acylamino, halogens and a group which links to a polymer, provided that the total number of carbon atoms contained in R³ and R⁴ is at least 6 if neither R³ nor R⁴ is a group which links to a polymer; and
X is hydrogen or a coupling-off group selected from the group consisting of halogens, alkoxy, aryloxy, alkylthio, arylthio, acyloxy, sulfonamido, carbonamido, arylazo, nitrogen-containing heterocyclic and imido groups.