JPH0679138B2 - Silver halide photographic light-sensitive material - Google Patents

Description

The present invention relates to a silver halide photographic light-sensitive material, and more specifically, to a halogen which has been spectrally sensitized in the near infrared region by a specific rhodocyanine dye. The present invention relates to a silver halide photographic light-sensitive material.

[Prior art]

The photographic light-sensitive material is required to have high sensitivity in different specific wavelength regions depending on the purpose of use.
As one of the manufacturing techniques of such a light-sensitive material, various types of cyanine dyes and merocyanine dyes are added to a silver halide photographic emulsion, and a specific wavelength is specified in a wavelength region longer than the light-sensitive wavelength region peculiar to the silver halide. It is generally well known that the sensitivity in the wavelength region of is effectively increased. Among these, although various types of dyes in the near infrared region have been studied so far, there are few that satisfy photographic characteristics such as sensitization. That is, when the near-infrared spectral sensitization method is applied to a silver halide photographic emulsion depending on the dye, not only the addition of the spectral sensitizing effect and the increase in sensitivity but also the following requirements are satisfied. Must be something that

(1) The spectral sensitization range is appropriate. (2) No adverse interaction with other photographic additives. (3) Stable photographic characteristics are maintained during storage of the light-sensitive material.
(4) It is required that no stain or fog is left due to residual dye that has been administered for spectral sensitization after development.

[Object of the Invention]

Therefore, it is a first object of the present invention to provide a spectrally sensitized silver halide photographic light-sensitive material which has high sensitivity in the near infrared region and is less contaminated by residual dye and less fog.

A second object of the present invention is to provide a spectrally sensitized silver halide photographic light-sensitive material which causes less sensitivity reduction and fog when the manufactured light-sensitive material is stored.

[Structure of Invention]

As a result of various studies, the present inventors have found that the above-mentioned objects are at least one of novel rhodocyanine dyes represented by the following general formula
It has been found that this can be effectively achieved by incorporating the same in a silver halide photographic emulsion.

General formula In the formula, Z ₁ represents an atomic group necessary for forming a thiazole, benzothiazole or naphthothiazole ring. These thiazole ring and condensed benzene ring or naphthalene ring may be an alkyl group (preferably lower alkyl group such as methyl or ethyl), an aryl group (eg phenyl group), a hydroxy group, an alkoxy group (preferably methoxy, ethoxy, etc.). Lower alkoxy group), a carboxy group, an alkoxycarbonyl group (preferably a lower alkoxycarbonyl group such as methoxycarbonyl and ethoxycarbonyl), a halogen atom (eg, fluorine, chlorine, bromine, iodine, etc.) May be. Z ₂ represents an atomic group necessary for forming a 5- or 6-membered nitrogen-containing heterocycle. Specific examples thereof include, for example, an oxazole ring, a benzoxazole ring, a benzisoxazole ring, a naphthoxazole ring, a thiazole ring, a benzothiazole ring, a naphthothiazole ring, a selenazole ring, a benzoselenazole ring,
Naphthoxazole benzoselenazole ring, a pyridine ring, quinoline ring, benzoquinoline ring, indolenine ring, benzindolenine ring, benzimidazole ring, include naphthoimidazole imidazole ring, Z ₁ in these heterocycles and fused benzene ring or a naphthalene ring It may have a substituent as described above. Of these, a benzoxazole ring, a naphthoxazole ring, a thiazole ring, a benzothiazole ring and a naphthothiazole ring are preferably used. R ₁ , R ₃ ,
R ₄ is an alkyl group (eg, lower alkyl group such as methyl, ethyl, propyl, butyl, etc., hydroxyalkyl group such as β-hydroxyethyl, γ-hydroxypropyl, alkoxyalkyl such as β-methoxyethyl, γ-methoxypropyl, etc. Group, acyloxyalkyl group such as β-acetoxyethyl, γ-acetoxypropyl, β-benzoyloxyethyl and the like, carboxyalkyl group such as carboxymethyl and β-carboxyethyl, methoxycarbonylmethyl, ethoxycarbonylmethyl, β-ethoxycarbonylethyl and the like An alkoxycarbonylalkyl group of
It represents a sulfoalkyl group such as β-sulfoethyl, γ-sulfopropyl, δ-sulfobutyl, etc.), an aralkyl group (eg, benzyl, phenethyl, sulfobenzyl, etc.), and an alkenyl group (eg, allyl). R ₂ is the above R ₁ ,
It represents an alkyl group, an aralkyl group, an alkenyl group or an aryl group (for example, phenyl, tolyl, methoxyphenyl, chlorophenyl, naphthyl etc.) as described for R ₃ and R ₄ . X ⁻ represents an acid anion (for example, alkylsulfate ion such as methylsulfate and ethylsulfate, thiocyanate ion, toluenesulfonate ion, halogen ion such as chlorine, bromine, iodine, and perchlorate ion), and the dye has a betaine structure. Does not exist when taking. m represents 1 or 2.

Next, typical examples of the dye used in the present invention will be given.

Next, typical examples of the synthesis of the novel rhodocyanine dye used in the present invention will be described.

Synthesis of dye example (4): 3-Ethyl-5- [3- (3-ethylbenzothiazoline-2-ylidene) methyl-5,5-dimethyl-2-cyclohexene-1-ylidene] rhodanine (US Pat. No. 2 , 85
2.21 g and 3.15 g of dimethyl sulfate were mixed and heated to a bath temperature of 90 to 100 ° C. for 15 minutes. After cooling, the reaction product was washed with ethyl ether and then 2- (2-ethoxy-1).
-Propenyl) -3-ethyl-5,6-dimethylbenzoxazolium-P-toluenesulfonate (2.16 g) and ethanol (30 ml) were added and heated to obtain a uniform solution. Next, 3.0 ml of triethylamine was added, and the mixture was heated under reflux for 30 minutes. After the reaction, ethyl acetate was added to collect a crystallized product. After washing with ethyl acetate, the crude dye is recrystallized twice with ethanol and dried to give a dark yellow-green crystalline powder with a melting point of 197.0 ° C (decomposition) 1.0
I got 0g. The absorption maximum of the methanol solution was 689 nm.

Other dyes used in the present invention can be easily synthesized according to the above-mentioned synthesis examples.

The absorption maximum value (nm) of the methanol solution of the representative example used in the present invention is as follows.

Dye (1) 693 Dye (2) 708 (3) 698 (4) 689 (5) 719 (6) 716 (7) 717 (8) 721 (9) 750 (10) 732 (11) 747 (12) 740 (13) 737 (14) 685 (15) 674 (16) 723 (17) 721 (18) 725 (19) 670 (20) 717 (21) 708 (22) 743 (23) 722 * Dimethylformamide solution The present invention The silver halide photographic emulsion used in Step 1 may be any of silver chloride, silver bromide, silver chlorobromide, silver iodobromide, silver chloroiodobromide and the like produced by a conventional method. To add the dye used in the present invention to these silver halide photographic emulsions, an organic solvent such as methanol, ethanol, acetone, cellosolve, pyridine, or dimethylformami, which is optionally miscible with an aqueous solution or water, may be used. It can be added as a solution of a mixed solvent. The dye may be added to the silver halide photographic emulsion at any time during the emulsion manufacturing process, but it is generally preferable to add the dye just before the end of the second ripening. The addition amount varies depending on the type of dye or the type of silver halide photographic emulsion,
Converted to silver nitrate, it can be used in a wide range of about 4 to 1,200 mg per 100 g.

The silver halide photographic emulsion used in the present invention may be subjected to noble metal sensitization, sulfur sensitization, reduction sensitization and sensitization in combination thereof, or addition of a polyalkylene oxide compound or the like. .

The silver halide photographic emulsion of the present invention may be spectrally sensitized with other sensitizing dyes, for example, known cyanine and merocyanine dyes, if necessary, by a known method.
Additions such as stabilizers, surfactants, hardeners, brighteners, UV absorbers, filter dyes, anti-irradiation dyes, anti-halation dyes, preservatives, plasticizers, matting agents, color couplers, etc. Agents can be included. Further, when it is used in a light-sensitive material for stabilization processing,
A developing agent or its precursor can be included.

Examples of the protective colloid of the silver halide photographic emulsion of the present invention include gelatin, gelatin derivatives such as phthalated gelatin and malonated gelatin, cellulose derivatives, soluble starch, water-soluble polymers and the like.

As the support used in the present invention, for example, baryta paper, plastic-laminated paper, synthetic paper, resin film of cellulose triacetate, polyethylene terephthalate, etc. can be used. If necessary, an undercoat layer and an antihalation layer may be provided on these supports by a known method.

Hereinafter, the present invention will be described in detail based on Examples, but the present invention is not of course limited thereto.

Example: A 0.01% solution of the sensitizing dye used in the present invention and the comparative sensitizing dye described below was added to a silver chloride emulsion prepared by a conventional method for producing a silver halide photographic emulsion, and converted to silver nitrate to obtain g.
3 ml was added per unit. This emulsion was aged in a bath at 40 ° C. for 45 minutes to stabilize the spectral sensitizing effect. After that, a stabilizer, a surfactant, and a hardening agent were added in predetermined amounts, and the mixture was coated on a polyethylene-laminated paper support, dried, and stored overnight at 35 ° C. Then, it was cut into an appropriate size to obtain a test sample (fresh). Some of this test sample is 50
It was aged for 3 days under the conditions of ° C and 80% relative humidity (thermo). These test samples were subjected to optical wedge exposure using a sensitometer having a light source with a color temperature of 5,400 ° K and a dark red filter (SC-70 manufactured by Fuji Photo Film Co., Ltd.) attached to the light source. After exposure, each sample was developed for 90 seconds at 20 ° C. using D-72 developer (developing solution of Eastman Kodak Company, USA), and stopped.
After fixing and further washing with water and drying, strips having a predetermined black and white image were obtained. The density was measured using a MACBETH-TD-504 densitometer manufactured by Macbeth Corporation in the United States to obtain sensitivity and fog. The reference point of the optical density at which the sensitivity was determined was [fog + 0.30]. The sensitivity is shown in Table 1 as a relative value with the fresh sensitivity of the comparative dye F being 1.0.

(Comparative sensitizing dye A) (Same B) (Same C) (Same D) (Same E) (Same F) As is clear from Table 1 above, it can be seen that the novel rhodocyanine dye used in the present invention has high spectral sensitivity in the near infrared region. Further, the sensitivity and fog hardly changed in the sample aged for 3 days at 50 ° C. and 80% relative humidity.

Claims (1)

[Claims] 1. A silver halide photographic light-sensitive material containing at least one sensitizing dye represented by the following general formula. General formula (In the formula, Z ₁ represents an atomic group necessary for forming a thiazole, benzothiazole or naphthothiazole ring, and Z ₂ represents an atomic group necessary for forming a 5- or 6-membered nitrogen-containing heterocycle. R ₁ , R ₃ and R ₄ represent an alkyl group, an aralkyl group and an alkenyl group, respectively, R ₂ represents an alkyl group, an aralkyl group, an alkenyl group and an aryl group, X ⁻ represents an acid anion, and m and n represent Represents 1 or 2 respectively.)