SILVER HALIDE COLOR PHOTO-SENSITIVE MATERIAL

Abstract: A silver halide photo-sensitive material having at least one silver halide emulsion layer on a support the silver halide emul­ sion layer containing at least one magenta-forming coupler of the 1H-pyrazolo[3,2-c]-S-triazole type which is substituted by a tertiary alkyl group at the 3-position and, by a releasable group other than a hydrogen atom at the 7-position.

Description: BACKGROUND OF THE INVENTION The invention relates to a silver halide color photo-sensitive material which is highly color developable, and forms a magenta dye image having improved preservability, and especially improved light resistance. In more detail, the invention relates to a silver halide color photo-sensitive material which contains a novel magenta-forming coupler of the 1H-pyrazolo[3,2-C]-s-triazole type. In general, a silver halide color photo-sensitive material exhibits a dye image in that exposed silver halide grains are reduced by a color developing agent of aromatic primary amine type, and that the resulting oxidation product of said color developing agent is coupled with yellow-, magenta-, and cyan-forming couplers. While the coupler conventionally used to form said magenta dye has been of the pyrazolone type, it has shortcomings in that it exhibits undesirable secondary absorptions, and has poor preservability, and especially formaldehyde gas resistance. For the purpose of overcoming such shortcomings, various magenta-forming couplers of 1H-pyrazolo[3,2-c]-s-triazole type have been proposed so far. These couplers, which have been described in U.S. Patent No. 3,725,067, and British Patent Nos. 1,252,418 and 1,334,515, for example, surpass magenta-forming couplers of pyrazolone type in terms of elimination of secondary absorptions, but still have insufficient formaldehyde resistance and show little improvement in light resistance of the dye image. Compounds described in Research Disclosure, No. 12443 also can not be put to practical use in terms of color developability at all. Magenta-forming couplers of 1H-pyrazolo [3,2-c]-s-triazole type, described in Japanese Patent O.P.I. Publication No. 42045/1983, possess considerably improved formaldehyde resistance and color developability, but are still lacking in terms of light resistance of the dye image. Couplers described in Japanese Patent O.P.I. Publication Nos. 99437/1984 and 125732/1984 also possess improved color developability, but have less improved light resistance of the dye image. In case of those described in the latter Publication No. 125732/1984, the light resistance of the dye image is only improved if the coupler is used with another additive. Only the coupler of Compound No. 19 in the specification of the former Publication No. 99437/1984 possesses somewhat improved light resistance of the dye image, but is still unsatisfactory. Thus, while magenta-forming couplers of the 1H-pyrazolo [3,2-c]-s-triazole type have been considered because they eliminate secondary absorptions, and possess high formaldehyde resistance, it should be noted that they show little improvement in terms of light resistance of the dye image. DE-A-1810464 discloses, inter alia , 1H-pyrazolo[3,2-c]-5-triazoles in which the 3 and/or 6 position can be substituted by alkyl, aralkyl, aryl or heterocyclic groups or a primary, secondary or tertiary amino group or an acylamido, hydroxy, alkoxy, carboxyl or ester group. Examples of possible alkyl substituents, amongst many others, include tertiary-butyl, tertiary amyl and tertiary pentyl. GB-2132783A discloses couplers of the formula: where A₁ and A₂ represent a wide variety of different substituents which R₁ and R₂ independently represent hydrogen or an alkyl, aryl, heterocyclic, acylamino, alkylamino, anilino, alkoxycarbonyl or alkylthio group. Tertiary butyl is one of the exemplified alkyl groups. The object of the invention is to provide a silver halide color photo-sensitive material which possess not only excellent light resistance and formaldehyde resistance, but also has good color developability. According to the present invention there is provided a silver halide color photo-sensitive material having at least one silver halide emulsion layer on a support, characterized by that said silver halide emulsion layer contains at least one magenta-forming coupler of 1H-pyrazolo[3,2-c]-s-triazole type which is substituted by a tertiary alkyl group (as hereinafter defined) at the 3-position, and by another releasable group than a hydrogen atom at the 7-position. As a result of various studies aiming at a solution of the aforementioned problems, we have found magenta-forming couplers of 1H-pyrazolo[3,2-c]-s-triazole type which possess excellent formaldehyde resistances and light resistance as well as having high color developability. They are couplers of 1H-pyrazolo[3,2-c]-s-triazole type which are substituted by a tertiary alkyl group at the 3-position, and by another releasable group than a hydrogen atom at the 7-position. In other words, it was found that 1H-pyrazolo[3,2-c]-s-triazole compounds can have improved light resistance of the image, along with a high color developability when substituted by a tertiary alkyl group at the 3-position, and by another releasable group than a hydrogen atom at the 7-position. By "tertiary alkyl", as used herein, is meant a group in which the carbon atom directly attached to the heterocyclic ring is not substituted by hydrogen. As for said releasable group, the 7-position of a 1H-pyrazolo[3,2-c]-s-triazole compound is the position where said compound couples with the oxidation product of a color developing agent to form a magenta dye, and said releasable group at the 7-position is released through said coupling reaction. Said 1H-pyrazolo[3,2-c]-s-triazole compound which is substituted by a tertiary alkyl group at the 3-position, and by a releasable group other than a hydrogen group at the 7-position, is represented the following general formula: where R₁ is an optionally tertiary alkyl group (as hereinbefore defined); R₂ is an optionally substituted alkyl, aryl or heterocyclic group. X is a releasable group other than a hydrogen atom, which is released through a coupling reaction of said compound with the oxidation product of a color developing agent. The tertiary carbon atom of said tertiary alkyl group represented by R₁ can be substituted by, instead of an alkyl group, such an aryl group as a phenyl group; an alkoxy group an aryloxy group or an alkylthio group. In addition, said tertiary carbon atom can participate also in the formation of another cyclic group. Furthermore, an alkyl group attached to said tertiary carbon atom can be substituted by, for example, a halogen atom; an aryl group such as a phenyl group; a cyano group; a substituent group which links through a carbonyl group, such as an alkoxycarbonyl acyl, or carbamoyl group; or a substituent group which links through a hetero atom, such as a nitro,alkoxy, alkylthio, arylthio, alkylsulfonyl, arylsulfonyl, alkylsulfinyl, arylsulfinyl, or dialkylamio group. Such a substituent group is preferably an alkylthio, alkylsulfonyl, arylsulfonyl, alkylsulfinyl or arylsulfinyl group. Further, needless to say, magenta-forming couplers in the invention include also bis-type 1H-pyrazolo[3,2-c]-s-triazole compounds, which are formed when the heterocyclic residue is a 1H-pyrazolo[3,2-c]-s-triazol-3-yl residue. Such tertiary alkyl groups as above include tert-butyl, 1,1-dimethyl-2-methoxyethyl, 1,1-dimethyl-2-chloroethyl, 1-methyl-1-phenylethyl, 1,1-di-n-amylhexyl, 7,7-dimethylnorbornan-1-yl, 1,1-dimethylbutyl, 1-ethyl-1-methylpropyl, and adamantyl groups. The alkyl group represented by R₂ can be either primary, secondary or tertiary, and can be substituted by a cyclic group, or any of the same groups as those for R₁ cited above. The aryl group represented by R₂ is preferably a substituted or unsubstituted phenyl group. Substituent groups for said substituted group include alkyl, halogen, hydroxy, cyano, nitro, alkoxy, acylamino, sulfonamido, alkoxycarbonyl, carbamoyl, and carboxy group. The heterocyclic group represented by R₂ is typically a furyl, thienyl, or pyridyl group. Such a heterocyclic group can be substituted by any of the same substituent groups as those for the above aryl group of R₂. The releasable group represented by X is typically a halogen atom, or an organic group linked through an oxygen, nitrogen, or sulfur atom. Among such releasable groups, those liked through an oxygen atom include alkoxy, aryloxy, acyloxy, and heterocycloxy groups. Those linked through an nitrogen atom include acylamino, diacylamino, and sulfonamido groups, and said-nitrogen-containing 5- or 6- membered heterocyclic groups. Those linked through an sulfur atom include thiocyano, alkylthio, arylthio, heterocyclothio, arylsulfonyl, and alkylsulfonyl groups. Exemplary compounds of the invention are listed below: A description of typical synthetic processes for the couplers of the invention is given below. The experimental synthesis was carried out referring to the description in Research Disclosure, No. 12443; Journal of the Chemical Society I, 1977, P. 2047-2052; U.S. Patent No. 3,725,067; and Japanese Patent C.P.I. Publication No. 99437/1984. Synthesis of Compound (14) The reaction scheme of the synthesis of Exemplary Compound (14) is represented as follows: Compound (14) Synthesis of (I) First, 21.2g of thiocarbohydrazide is added to 500 ml of ethanol, and refluxed. Then, 21.2g of benzaldehyde is added dropwise to the solution, and refluxed for 1 hour. Further, 70g of methyl α-chloro- α-palmitoylacetate is added to the solution, and refluxed for 5 hours. The resulting sulfur is filtered out, and the filtrate is mixed with 30g of hydrazine hydrate and is refluxed for 2 hours. On being cooled, the crude compound (I) is precipitated. The precipitate is filtered off, washed with water, and recrystallized from ethanol to obtain 31g of the purified compound (I). Synthesis of (II) 27.5g of (I) and 7.6g of triethylamine are added to 200 ml of chloroform, and boiled under stirring. Then, 9.1g of pivaloyl chloride is added dropwise to the solution, and refluxed for 1 hour. On being cooled, the resulting solution is washed with water, and dried with magnesium sulfate, and then chloroform is distilled off to precipitate crystals. 27.6g of the compound (II) is obtained by recrystallization of the crystals from acetone. Synthesis of (III) 27.0g of (II) and 9.3g of phosphorus exychloride are added to 200 ml of toluene, and refluxed for 4 hours. After removal of the toluene by distillation under reduced pressure, the residue is mixed with 200 ml of acetonitrile and 12g of pyridine, and refluxed for 1.5 hours. On being cooled, the resulting solution is poured into water to precipitate the crude compound (III). This is filtered, washed with water, dried, and recrystallized from n-hexane to obtain 20.2g of the pure compound (III). Synthesis of (IV) First, 18g of (III) is added to a mixture of 100 ml glacial acetic acid, 10 ml of concentrated sulfuric acid, and 5 ml of water, and refluxed for 8 hours. After being allowed to cool, the resulting solution is poured into ice water, and neutralized with sodium hydroxide. The resulting precipitate is filtered off, washed well with water, dried, and recrystallized from acetonitrile to obtain 12.2g of the compound (IV). Synthesis of Exemplary Compound (14) First, 11.2g of (IV) is dissolved in 100 ml of chloroform. The solution is mixed with 4.0g of N-chlorosuccinimide, and is allowed to react together for 1 hour at room temperature. The resulting solution is washed with dilute alkali solution, and then washed with water well. After distilling off the chloroform, the residue is purified by column chromatography using silica gel carrier, and n-hexane/ethyl acetate (3:1) developing solvent. The product is recrystallized to obtain 6.8g of Compound (14), identified by nuclear magnetic resonance spectrometry and mass spectrometry. The silver halide color photo-sensitive material formed by the invention can contain a conventional dye-forming coupler in combination with that of the invention. As a yellow-developing coupler among such conventional couplers, well-known compounds of open-chain type can be used; compounds of the benzoylacetanilide or pivaloylacetanilide type are especially useful. Such yellow-developing couplers include compounds described in U.S. Patent Nos. 2,875,057, 3,265,506, 3,408,194, 3,551,155, 3,582,322, 3,725,072 and 3,891,445; West German Patent No. 1,547,868; West German OLS Patent Nos. 2,219,917, 2,261,361 and 2,414,006; British Patent No. 1,425,020; Japanese Patent Examined Publication No. 10783/1976; and Japanese Patent O.P.I. Publication Nos. 26133/1972, 73147/1973, 102636/1976, 6341/1975, 123342/ 1976, 130442/1975, 21827/1976, 87650/1975, 82424/1977 and 115219/1977. As useful cyan-developing couplers, there are cited phenol compounds, and naphthol compounds which include compounds described, for example, in U.S. Patent Nos. 2,369,929 2,434,272, 2,474,293, 2,521,908, 2,895,826, 3,034,892, 3,311,476, 3,458,315, 3,476,563, 3,583,971, 3,591,383, 3,767,411 and 4,004,929; West German Patent Application (OLS) Nos. 2,414,830 and 2,454,329; Japanese Patent O.P.I. Publication Nos. 59838/1973, 26034/1976, 5055/1973, 146828/1976, 69624/1977 and 90932/1977. As magenta-developing coupler, each of couplers of the invention can be used singly or in combination of two or more. In addition, it can be used in combination with a well-known conventional coupler such as pyrazolone, indazolone, cyanoacetyl, pyrazolinobenzimidazole, and pyrazolotriazole compounds as the case may be. Further, a colored coupler having a color correcting effect, or a coupler (DIR Coupler) releasing a development inhibitor, can be used in combination with a coupler of the invention if necessary. The incorporation of a magenta-forming coupler of the invention, and of other couplers such as the above into a silver halide emulsion layer can be conducted by well-known methods including the method described in U.S. Patent No. 2,322,027. Said couplers are dissolved into, for example, such a solvent as an alkyl phthalate such as dibutyl phthalate and dioctyl phthalate; a phosphoric acid ester such as diphenyl phosphate, triphenyl phosphate, tricresyl phosphate, and dioctyl butyl phosphate; a citric acid ester such as tributyl acetylcitrate; a benzoic acid ester such as octyl benzoate; an alkylamide such as diethyllauramide;an aliphatic acid ester such as dibutoxyethyl succinate, and dioctyl acetate; a trimesic acid ester such as tributyl trimesate; and an organic solvent boiling at about 30 to 150 °C such as ethyl acetate, butyl acetate, ethyl propionate, sec-butyl alcohol, methyl isobutyl ketone, β-ethoxyethyl acetate, and methyl cellosolve acetate, and then dispersed into a hydrophilic colloid. As a solvent, a mixture of a higher-boiling solvent and a lower-boiling solvent among the above can also be used. In addition, the dispersing process with polymer, described in Japanese Patent Examined Publication No. 39853/ 1976, and Japanese Patent O.P.I. Publication No. 59943/1976, also can be used. A magenta-forming coupler of the invention is added to a silver halide emulsion usually in the range of 0,005 to 2 moles per mole of silver halide, and preferably 0.03 to 0.5 moles per mole of silver halide. While the dye image formed by a magenta-forming coupler of the invention generally exhibits a strong light-resistance by itself, the light resistance can be further improved by the combined use of an antifading agent, or by the addition of a UV absorber-containing layer on the upper side. As such antifading agents, there are cited, for example, hydroquinone derivatives described in U.S. Patent Nos. 2,360,290, 2,418,613, 2,675,314, 2,701,197, 2,704,713, 2,728,659, 2,732,300 2,735,765, 2,710,801 and 2,816,028, and British Patent No. 1,363,921; gallic acid derivatives described in U.S. Patent Nos. 3,457,079 and 3,069,262; p-alkoxyphenol compounds described in U.S. Patent Nos. 2,735,765 and 3,698,909, and Japanese Patent Examined Publication Nos. 20977/1974 and 6623/1977; p-oxyphenol derivatives described in U.S. Patent Nos. 3,432,300, 3,573,050, 3,574,627 and 3,764,337, and Japanese Patent O.P.I. Publication Nos. 35633/1977, 147434/1977 and 152225/1977; and bisphenol compounds described in U.S. Patent No. 3,700,455. As the above UV absorber, there are cited, for example, aryl-substituted benzotriazole compounds described, for example, in U.S. Patent No. 3,533,794; 4-thiazolidone compounds described, for example, in U.S. Patent Nos. 3,314,794 and 3,352,681; benzophenone compounds described, for example, in Japanese Patent O.P.I. Publication No. 2784/1971; cinnamic acid ester compounds described, for example, in U.S. Patent Nos. 3,705,805 and 3,707,375; butadiene compounds described, for example, in U.S. Patent No. 4,045,229; benzoxidole compounds described, for example, in U.S. Patent No. 3,700,455; and compounds described in U.S. Patent No. 3,499,762, and Japanese Patent O.P.I. Publication No. 48535/1979. As silver halide used in the silver halide emulsion in the invention, there can be used those commonly used silver halide emulsions, such as silver bromide, silver chloride, silver iodobromide, silver chlorobromide, and silver chloro-iodobromide emulsions. The silver halide used in the invention can be spectrosensitized by an appropriately selected sensitizing dye so as to be provided with a color sensitivity to light of the required range of wavelength. Said sensitizing dyes include cyanine dyes, merocyanine dyes, composite cyanine dyes, composite merocyanine dyes, homopolar cyanine dyes, hemicyanine dyes, styryl dyes, and hemioxonole dyes. Especially useful sensitizing dyes are those described, for example, in West German Patent No. 929,080; U.S. Patent Nos. 2,231,658, 2,493,748, 2,503,776, 2,519,001, 2,912,329, 3,656,959, 3,672,897, 3,694,217, 4,025,349 and 4,046,572; British Patent No. 1,242,588; and Japanese Patent Examined Publication Nos. 14030/1969 and 24844/1977. While these sensitizing dyes can be used either singly or in combination with one another, they are often used in combination for the purpose of intensive sensitization, as typically shown, for example, in U.S. Patent Nos. 2,688,545, 2,977,229, 3,897,060, 3,522,052, 3,527,641, 3,617,293, 3,628,964, 3,666,480, 3,672,898, 3,679,428, 3,703,377, 3,769,301, 3,814,609, 3,837,862 and 4,026,707; British Patent Nos. 1,344,281 and 1,507,803; Japanese Patent Examined Publication Nos. 4936/1968 and 12375/1978; and Japanese Patent O.P.I. Publication Nos. 110618/1977 and 109925/1977. Silver halide emulsions used in the invention can contain various well-known photographic additives described, for example, in Research Disclosure, No. 17643. The support of the silver halide color photo-sensitive material of the invention can be selected from among well-known materials including plastic film, plastic-laminated paper, baryta paper, and synthetic paper, according to the intended purpose. The thus constituted silver halide color photo-sensitive material of the invention can be submitted to various color developing processings after exposure. Color developing agents of aromatic primary amine type used in color developers include well-known compounds widely used in various color photographic processings. These developing agents include both aminophenol derivatives, and p-phenylenediamine derivatives. In general, these compounds are used in the form of a salt such as hydro - chloride and sulfate rather than in the form of free amine, because of more stable nature of the salt. They are usually used at concentrations from, say, 0.1 to 30 grams, and preferably from 1 to 1.5 grams per liter of developer. Said developing agents of the aminophenol type include o-aminophenol, p-aminophenol 5-amino-2-hydroxytoluene, 2-amino-3-hydroxytoluene, and 2-hydroxy-3-amino-1-4-dimethylbenzene, for example. Especially useful color developing agents of aromatic primary amine type are N,N'-dialkyl-p-phenylenediamine compounds whose alkyl groups and/or phenylene group can have a variety of substituent groups. Thus, especially useful compounds are N,N'-diethyl-p-phenylenediamine hydrochloride, N-methyl-p-phenylenediamine hydrochloride, N,N'-dimethyl-p-phenylenediamine hydrochloride, 2-amine-5-(N-ethyl-N-dodecylamino) toluene, N-ethyl-N-β-methanesulfonamidoethyl-s-methyl-4-aminoaniline sulfate, N-ethyl -N-β-hydroxyethylaminoaniline, 4-amino-3-methyl-N,N'-diethylaniline, and 4-amino-4-(2-methoxyethyl)-N-ethyl-3-methylaniline p-toluenesulfonate, for example. A color developer used for processing the emulsion of the invention can contain, besides the color developing agent of aromatic primary amine type, various additives, which are commonly added to color developers, such as sodium hydroxide, sodium carbonate, and other alkaline agents; alkali metal sulfites, alkali metal bisulfites, alkali metal thiocyanates, alkali metal halides, benzyl alcohol, water-softening agents, and thickening agents. The p H of the color developer used in the invention is usually more than 7.0, and very often from 10 to 13. After color development, the silver halide photo-sensitive material of the invention can be treated with a processing solution capable of fixing the color. When said processing solution is a fixer, said material is first submitted to a bleaching treatment. A metal complex of an organic acid is usually used as a bleaching agent in the bleaching solution or bleach-fix solution used in said bleaching process. Such a metal complex is capable of oxidizing metallic silver formed through the developing process, to silver halide, and of color-developing undeveloped part of the color developing agent at the same time. Said metal complex is formed by coordinating a metal such as iron, cobalt, and copper to an organic acid such as an aminopolycarboxylic acid, oxalic acid or citric acid. Especially preferable are polycarboxylic acids and aminopolycarboxylic acid. Said polycarboxylic acid, or aminopolycarboxylic acid, is useful also in the form of its alkali metal or ammonium salt, or water-soluble amine salt. Thus organic acids, and their salts useful to form said metal complexes include the following typical compounds: (1) Ethylenediaminetetraacetic acid (2) Diethylenetriaminepentaacetic acid (3) Ethylenediamine-N-(β-hydroxyethyl)-N,N',N'triacetic acid (4) Propylenediaminetetraacetic acid (5) Nitrilotriacetic acid (6) Cyclohexanediaminetetraacetic acid (7) Iminodiacetic acid (8) Dihydroxyethylglycinecitric acid (or -succinic acid) (9) Ethyletherdiaminetetraacetic acid (10) Glycoletherdiaminetetraacetic acid (11) Ethylenediaminetetrapropionic acid (12) Phenylenediaminetetraacetic acid (13) Disodium ethylenediaminetetraacetate (14) Tetratrimethylammonium ethylenediaminetetraacetate (15) Tetrasodium ethylenediaminetetraacetate (16) Pentasodium diethylenetriaminepentaacetate (17) Sodium ethylenediamine-N-(β-hydroxyethyl)-N,N', N'-triacetate (18) Sodium propylenediaminetetraacetate (19) Sodium nitrilotriacetate (20) Sodium cyclohexanediaminetetraacetate The bleaching solution used in said processing can contain various additives besides the above organic acid salts. Such additives are, especially, alkali or ammonium halides as rehalogenation agent such as potassium bromide, sodium bromide, sodium chloride, and ammonium bromide; metal salts; and sequestering agents. The bleaching solution can contain also various other additives well-known as common bleaching solution additives, such as borates, oxalates, acetates, carbonates and phosphates as a p H buffer agent; alkylamines; and polyethylene oxide compounds. Further, said fixer or bleach-fix solution can contain, either singly or in combination of two or more, p H buffer which is composed of sulfites such as ammonium sulfite, potassium sulfite, ammonium bisulfite, potassium bisulfite, sodium bisulfite, ammonium metabisulfite, potassium metabisulfite and sodium metabisulfite; boric acid, boxax, sodium hydroxide; salts such as sodium carbonate, potassium carbonate, sodium bicarbonate, potassium bicarbonate and sodium acetate; acetic acid, and ammonium hydroxide. When the bleach-fix processing is conducted while more bleach-fix solution is added to the bleach-fix bath, salts such as thiosulfates, thiocyanates, and bisulfates can be present either in said bleach-fix bath, or said supplementary bleach-fix solution. In the invention, it is allowed, for the purpose of improving the activity of the bleach-fix solution, that air or oxygen is blown into either bath or storage vessel of the solution, or that an oxidizing agent such as hydrogen peroxide, bromate, and persulfate is added, as required. (Examples) Further illustration of the invention is made in the following Examples. °Example 1. Both magenta-forming couplers of the invention, and couplers for reference are listed in Table 1; they were separately taken in an amount of 0.1 mole per mole of Ag, and throughly dissolved into the mixture of the same amount of tricresyl phosphate, and three-fold amount of ethyl acetate by heating at 60 °C. The solution was mixed with 1200 ml of a 5% gelatin aqueous solution which contained 120 ml of 5% Alkanol B (alkyl naphthalenesulfonate; E.I. du Pont) aqueous solution, and emulsified by an ultrasonic dispersing device. Then, the emulsified product was added to 4 kg of a green-sensitive silver iodobromide emulsion (containing 6 mole % of silver iodide), and was mixed with 120 ml of 2% 1,2-bis(vinyl-sulfonyl)ethane (as a hardener) methanolic aqueous (1:1) solution. The emulsion obtained was applied on an undercoated transparent polyester base at a rate of 20 mg of applied Ag per 100 cm² of base, to make the sample. The obtained sample, was exposed through an optical wedge in the usual way, and then submitted to the development processing. The results are shown in Table 1. Notes: 1) ... The specific sensitivity was represented as reciprocal of the exposure quantity which gave a density of (fog density ± 0,1), based on 100 for Sample No. 11. 2)... The formaldehyde (CH₂O) resistance was determined in the following way: 0.9% formaldehyde aqueous solution is prepared, and conditioned to 30 °C and 6% RH. Six(6) ml of the solution is placed in a closed vessel, The sample is placed in the vessel for 3 days, and then is color-developed. A reference sample untreated with formaldehyde also is color-developed concurrently. Formaldehyde resistance 3)... The light resistance was determined in the following way: The color developed sample is irradiated for 5 days by a xenon fade meter. The percent residual dye is determined based on 1.0 for the initial density. Light resistance Reference Coupler 1 Reference Coupler 2 It is clear from Table 1 that the couplers of the invention possess improved color developability, formaldehyde resistance, and light resistance in comparison with the reference couplers. °Example 2 Each of Samples 11 to 15 of Example 1 was exposed through an optical wedge in the same way as in Example 1, and developed and processed under the conditions cited below. The results are shown in Table 2. The specific sensitivity and the light resistance were determined in the same way as in Example 1. °Example 3 A silver halide color photo-sensitive material was prepared by applying the following layers (1) to (6) in this order on a support paper which had been coated with polyethylene resin containing anatase-form titanium dioxide. All the amounts of additives are represented as weight in mg per 100 cm² of support. (1)... A layer which contains 20 mg of gelatin, a blue-sensitive silver chlorobromide emulsion containing 5mg of Ag and 8 mg of a Y-coupler plus 0.1 mg of 2,5-di-tert-octylhydroquinone which has been dissolved in 3 mg of dioctyl phthalate. (2)... A UV absorber-containing intermediate layer which contains 12g of gelatin, and 0.5 mg of 2,5-di-tert-octylhydroquinone plus 4 mg of a UV absorber which has been dissolved in 2 mg of dibutyl phthalate. (3)... A layer which contains 18 mg of gelatin, a green-sensitive silver chlorobromide emulsion containing 4 mg of Ag, and 5 mg of an M-coupler plus 2 mg of an antioxidant plus 0.2 mg of 2,5-di-tert-octylhydroquinone which has been dissolved in 2,5 mg of dioctyl phthalate. (4)... An intermediate layer which contains the same additives as in the layer (2). (5)... A layer which contains 16 mg of gelatin, a red-sensitive silver chlorobromide emulsion containing 4 mg of As, and 3,5 mg of a C-coupler plus 0,1 mg of 2,5-di-tert-octylhydroquinone which has been dissolved in 2,0 mg of tricresyl phosphate. (6)... A protective gelatin layer which contains 9 mg of gelatin. Each of layers (1) to (6) was applied with a coating aid, and each of layers (4) and (6) was mixed with a gelatin cross-linking agent. As a UV absorber for layers (2) and (4), a mixture of compounds (UV-1) and (UV-2) was employed. As an autioxidant for the layer (3), di-tert-pentylhydroquinone dioctyl ether was used. The above multilayered photo-sensitive material was processed in the same way as in Example 2. The results obtained are shown in Table 3 with the kind of used Y-, M-, and C-couplers. Each sample was evaluated as to its magenta density after exposure to white light. The specific sensitivity and the light resistance were determined in the same way as in Example 1. It is clear from Table 3 that the couplers of the invention give improved light resistance of their dye image, and that said light resistance is further improved by the combined use of a UV absorber.

Claims: A silver halide photo-sensitive material having at least one silver halide emulsion layer on a support, the silver halide emulsion layer containing at least one magenta-forming coupler which is a compound of formula (I) wherein R₁ is an optionally substituted alkyl group in which the carbon atom linking the group directly to the heterocyclic ring is not attached to a hydrogen atom; R₂ is an optionally substituted alkyl group, aryl group or heterocyclic ring group; and X represents a releasable group other than hydrogen, susceptible to displacement by coupling reaction of the compound of formula (I) with the oxidation products of an aromatic amine color developing agent. The silver halide color photo-sensitive material as claimed in claim 1 wherein X is a halogen atom. The silver halide color photo-sensitive material as claimed in claim 1 or 2 wherein R₁ is a tertiary alkyl group having 4 to 30 carbon atoms. The silver halide color photo-sensitive material as claimed in any one of claims 1 to 3 wherein R₂ is an alkyl group having 1 to 30 carbon atoms. The silver halide color photo-sensitive material as claimed in any one of claims 1 to 4 having silver halide emulsion layers spectrally sensitized in blue, green and red, and wherein the green-sensitive layer contains a magenta-forming coupler of the 1H-pyrazolo-[3,2-c]-S-triazole type in an amount of from 0.005 mole to 2 mole per mole of the, silver halide used. The silver halide color photo-sensitive material as claimed in claim 5, wherein the green-sensitive layer contains a magenta-forming coupler of the 1H-pyrazolo[3,2-c]-S-triazole type in an amount of from 0.03 mole to 0.5 mole per mole of the silver halide used. The silver halide color photo-sensitive material as claimed in claim 5 or claim 6, wherein the blue-sensitive layer contains at least one yellow-forming benzoylacetanilide type or pivaloylacetanilide type coupler. The silver halide color photo-sensitive material as claimed in any one of claims 5 to 7 wherein the red-sensitive layer contains at least one cyan-forming phenol type or naphthol type coupler. A magenta- forming coupler which is a Compound of formula (I) as defined in any one of claims 1 to 4.

Inventors: KATOH, KATSUNORI, KAWAKATSU, SATOSHI, NAKAYAMA, NORITAKA, SHINOZAKI, KAORU
Applicants: KONICA CORPORATION
Application year: 1985
Main classification: G03C7
IPC codes: G03C7, C07D487