JPS60121440A - Direct positive silver halide emulsion - Google Patents

Abstract

PURPOSE:To obtain a direct positive photosensitive material high in sensitivity and contrast by using a specified dye. CONSTITUTION:A direct positive photosensitive emulsion high in sensitivity and contrast can be obtained by incorporating at least one of dimethine (vinylene) dyes prepared by combining the 3-position of a 5,6-dihydropyrrolo[2,1-a]isoquinoline ring and one of the 1,2,3,4, or 5-position of an N-contg. hetero ring with a dimethine (vinylene) chain, exemplified by formula I (R1, R2 are each H, alkyl, aryl, or the like; R3 is alkyl, alkenyl, or the like; Z is a nonmetallic atom group necessary to complete a 5- or 6-membered hetero ring, such as oxazoline ring; X<-> is an acid anion; and (m), (n) are each 1 or 2.), and typified by formula II, and using said dimethine dye for spectral sensitization. The use of a combination of said dye with an org. desensitizing dye can provide an emulsion far higher in sensitivity.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a direct positive silver halide emulsion, and more particularly to a 5,6-dihydropyrrolo r2.1-a emulsion.
) A direct positive silver halide emulsion spectrally sensitized by a novel dye in which the 3rd position of the isoquinoline ring and the 1st, 2nd, 3rd, 4th or 9th positions of the 5- or 6-membered nitrogen-containing heterocycle are bonded via a dimethine chain. It is related to.

Direct positive images can be produced using certain silver halide photographic emulsions. For example, as described in U.S. Pat. There are silver halide photographic emulsions.

In order to increase the sensitivity of this type of direct positive silver halide photographic emulsion, five-spectrum sensitization technology is used. Many dyes are known as spectral sensitizing dyes for ordinary negative emulsions, but when these dyes are used directly for spectral sensitization of positive silver halide photographic emulsions, there are many drawbacks, such as the characteristics This often causes the curve to soften and re-invert. Further, although many proposals have been made as spectral sensitizers for direct positive silver halide photographic emulsions, the reality is that few of them have a satisfactory sensitization rate. In recent years, in addition to conventional tungsten and xenon light, the light sources used in photographic materials have come to include light sources emitted from lasers and diodes as information processing speeds up, and there is a demand for higher sensitivity in photographic materials. is increasing.

2- As a result of repeated research in order to obtain a direct positive sensitizing dye with a high sensitization rate, the present inventors succeeded in obtaining a sensitizing dye that satisfies this objective.

The novel sensitizing dye used in the present invention that satisfies the above objectives is 5,6-dihydropyrrolo[2,1-a)in at the 3-position of the quinoline ring and at the 1-, 2-, 5- or 6-membered nitrogen-containing heterocycle.
It is a dye in which the 3.4 or 9-position is linked by a dimethine chain, and is represented by the following general formula.

In the general formula, R1 and R2 are hydrogen, an alkyl group (e.g., methyl, ethyl, propyl, isopropyl, butyl, tert, butyl, pentyl, hexyl, etc.), a cycloalkyl group (e.g., cyclopropyl, cyclohexyl, etc.), and 5-aralkenyl. groups (e.g. styryl, etc.), allyl groups (e.g. phenyl, 0-tolyl, m-tolyl, p-tolyl, p-tert, butylphenyl, 0-methoxyphenyl, p-methoxyphenyl, p -tart.

Octyloxyphenyl, m-chlorophenyl, p-chlorophenyl, 0-fluorophenyl, m-nitrophenyl, p-nitrophenyl, m-acetamidophenyl,
p-Benzamidophenyl, 3-10ro4-ethoxyphenyl, 4-methyl-3-nitrophenyl, 4-benzyloxy-3-bromophenyl, 5-chloro-4methoxyphenyl, 3.5-cyclo4 -ethoxyphenyl, m-sulfophenyl, m-fluorosulfonylphenyl, 3,5-difluorosulfonylphenyl, 2-
methoxy-5-fluorosulfonylphenyl, p-cyanophenyl, p-carboxyphenyl, p-ethoxycarbonylphenyl, etc.), 5- or 6-membered heterocyclic groups (e.g., 2-furyl, 3-pyridyl, 4-pyridyl, etc.) where Ri is an alkyl group or a substituted alkyl group as described above for R1 and R2 (for example, a hydroxyalkyl group such as β4-monohydroxyethyl% r-hydroxypropyl, β-acetoxyethyl, r-acetoxypropyl, β-benzoyl Acyloxyalkyl groups such as oxyethyl, alkoxyalkyl groups such as β-methoxyethyl, β-ethoxyethyl, β-1sopropoxyethyl, carboxyalkyl groups such as carboxymethyl, β-carboxyethyl, r-carboxypropyl,
Alkoxycarbonylalkyl groups such as methoxycarbonylmethyl, ethoxycarbonylmethyl, and β-ethoxycarbonylethyl, sulfoalkyl groups such as β-sulfophenyl, r-sulfopropyl, and δ-sulfobutyl), alkenyl groups (e.g., allyl, etc.), aralkyl groups represents a group (eg, benzyl, phenethyl, etc.).

2 is 5 or 6, which is well known in the chemistry of cyanine dyes.
Represents a group of nonmetallic atoms necessary to complete a membered nitrogen-containing heterocyclic nucleus, and its specific examples include an oxazinone nucleus, a dihydroxazine nucleus, an oxazole nucleus, a benzoxazole nucleus, a naphtho-5=xazole nucleus, and an oxazolopyridine nucleus. , thiazoline nucleus,
Thiazole nucleus, benzothiazole nucleus, naphthothiazole nucleus, thiazolopyridine nucleus, selenazole nucleus, benzoselenazole nucleus, naphthoselenazole nucleus, pyridine nucleus, quinoline nucleus, isoquinoline nucleus, imidazole nucleus, penzimidazole nucleus, naphthoimidazole nucleus, India renin nucleus,
S-triazolo r2.3-a) Pyridine nucleus.

tetrasilo ra] pyrimidine nucleus, imidazo (4,5-b
] Quinoxaline nucleus, naphthyridine nucleus, acridine nucleus, vilorin nucleus, 1,3,4-thiadiazole nucleus, etc. X
- represents an acid anion (e.g., methyl sulfate ion, ethyl sulfate ion, thiocyanate ion, p-toluenesulfonate ion, chloride ion, bromide ion, iodide ion, perchlorate ion, etc.). m and n are each 1 or 2.

Next, typical examples of dyes used in the present invention will be listed.

=6-1C! Ha ■- (3) (JH6 CHnO8Os- (7) C・H・1- 1″ (CH2) tcOOH- zHs CsHsO8O*- CL 1- CH・■- 9- CHs I- 1' CHa I- 10- 17 CHs V Ox 13- C*HsO8Os- Button) 1" C*Hm Knee 3Q ■- 14- 1' CxHs I- 1"- 2H5 ■- 9 1 Cd's CgHmO8On- T C2Ha c・HsO8Os- Ct Hs OS Os - Next, a representative example of the method for synthesizing the novel dimetine dye used in the present invention will be described.

Synthesis of dye 4: 1-*lumi-2-(p-nitrophenyl)-5,6-
Dihydropyrrolo r2.1-a) Isoquinoline 3.18
g and 3.15 g of 1.213.3.5-pentamethyl-3H-indolium iosite were washed with acetic anhydride for 20 hours. Next, recrystallization is performed with methanol, and after drying, the melting point is 286. Golden shining columnar crystals with OC (decomposition) of 3.50 were obtained.

Other dyes used in the present invention can also be easily synthesized according to the above synthesis example.

The absorption maximum values (nm) of methanol solutions of the representative examples of the dyes used in the present invention are as follows.

Pigment (11562 Pigment (2) 561(3) 54
8 (4) 541 (5) 556 (6) 567 (7) 559 (8) 531 (9) 566 αI5]8 (111542(1253B 1 542 (14548 (1!9) 540 α[9542 (17) 540 α Barrel 546 (11550611544 px) 555.571 94 559) 570
568 ni) 545 (b) 551 @ 545,565 (e) 559 @558 (g) 528,559 G(1) 568 ni) 571 t'11 569 (31) 570 (appetizer 569 t= 567 17- Dye) 569 18- In the present invention, a dimetine dye of the general formula can be added to a silver halogenide photographic emulsion by a known method. For example, it can be added as a solution in a solvent such as methanol, ethanol, isopropanol, pyridine, dimethylformamide, acetone, water, etc. alone or in combination.

It can also be added to the emulsion using ultrasonic dispersion. Additionally, methods known for negative emulsions, such as U.S. Pat. No. 3,484,981;
Same No. 3,469,987, Same No. 3,649.286, Same No. 3,485,634, Same No. 34λ605,
Also, the method described in the specification of Niss No. 2.9 No. 343 can also be used.

The amount of dimethine dye used in the present invention varies depending on various factors of the silver halide photographic emulsion.
Preferably IXIF'-2X10"mola/fn
o le AJ range.

Although the dye can be added to the emulsion at any stage of emulsion preparation, it is particularly preferred to add the dye immediately before coating.

Silver halide photographic emulsions used in the present invention include silver chloride, silver bromide, silver chlorobromide, silver iodide, silver chloroiodobromide, and silver iodobromide emulsions. In order to obtain a highly sensitive direct positive silver halide photographic emulsion, a silver halide photographic emulsion containing 580 mol % or more of bromide is preferred.

The silver halide photographic emulsion used in the present invention includes:
It includes both monodisperse and non-monodisperse,
Monodisperse ones are more preferable.

Further, the crystal habit of the silver halide photographic emulsion used in the present invention may be cubic or octahedral, but cubic is more preferred.

Furthermore, the grains of the silver norogenide photographic emulsion used in the present invention are preferably regular.

In the present invention, an emulsion may be used which has a nucleus for capturing free electrons inside the silver halide crystal and whose surface is capped with a chemical capping agent. The production of this type of emulsion can be done by e.g.
U.S. Patent No. 3,367°778, U.S. Patent No. 3,63434
No. 0 and No. 3,709,689.

The silver halogenide photographic emulsion used in the present invention is fogged by light or by a chemical capriagent.

Methods of chemically imparting capri include eg.

Antoine Hauto) -(Antoine Hauto)
t) and Henri Thorpe-Jv (Henri
Science at In
4strie+s Photography)2
Favorable results are obtained using the method of chemical sensitization described in Vol. 8, pp. 57-65 (published in 1957).

The silver halide photographic emulsion used in the present invention can give a fog of 5 by using a reducing agent.

Specific examples of the reducing agent include stannous chloride, thiourea dioxide, formalin, hydrazine and its derivatives, and amineborane.

The silver halide photographic emulsion used in the present invention can also be provided with a capri by using a gold compound. Specific examples of the gold compound include salt 21-compound acid, potassium chloroaurate, potassium thiosulfate, and the like.

Capri can also be imparted to the silver halide photographic emulsion used in the present invention by combining a reducing agent with a metal compound having a more negative potential than silver. As specific examples of metal compounds having a potential more negative than silver potential, in addition to the above-mentioned gold compounds, platinum compounds such as potassium chloroplatinate and iridium compounds such as potassium hexachloroiridate are used.

Furthermore, by using the above method in combination with a sulfur-containing sensitizer such as thiosulfate or allylthiourea, or a thiocyanate compound such as potassium thiocyanate, a silver halide photographic emulsion can be fogged. .

By combining the novel dimetine dye used in the present invention with a known organic desensitizing dye, it is possible to obtain a direct positive silver halogenide photographic emulsion with even higher sensitivity. Known dyes that have been proposed as spectral sensitizers for direct positive silver halide photographic emulsions can be combined with known organic desensitizing dyes to prevent coloring (color staining) caused by dyes remaining after development. However, even when the novel dimetine dye used in the present invention is combined with a known organic desensitizing dye, the coloration (color stain) caused by the dye remaining after the development process is extremely unlikely to be amplified.

A specific example of a known organic desensitizing dye used in the present invention is pinacryptol yellow.

Examples include phenosafranin, methylene blue, pinacryptol green%, 3-ethyl-5-metanitrobenzylidene rhodanine, 3,3'-diethyl-6,6'-dinitrothiacarbocyanine iodide, and the like.

Examples of the protective colloid used in the present invention include natural products such as gelatin, albumin, agar, gum arabic, and alginic acid, and water-soluble synthetic resins such as polyvinyl alcohol, polyvinylpyrrolidone, and cellulose ether.

In the present invention, various additives such as stabilizer 5 brightener, ultraviolet absorber 5 hardener, surfactant, preservative, plasticizer, matting agent, etc. can be included in the silver halide photographic emulsion. .

The support used in the present invention includes:

Examples include resin films such as polyethylene terephthalate and cellulose acetate, synthetic paper, and waterproof paper. Paper laminated with plastic can also be used. If necessary, a subbing layer can be provided on these supports by a known method.

A light-sensitive material coated with the direct positive silver halide photographic emulsion of the present invention is processed in a known processing bath for development, fixing, bleaching, etc., or a combination of these five processing baths.

The first feature of the present invention is that 5,6-dihydropyrrolo r2.
1-a) A highly sensitive direct positive silver halide photographic emulsion can be obtained by spectral sensitization using a novel dimethine dye containing an inquinoline ring.

The second feature of the present invention is that %5.6-dihydropyrrolo[2
, 1-a] In By using a novel dimethine dye containing a quinoline ring, a high contrast direct positive silver halide photographic emulsion can be obtained.

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

Example 1 A silver iodobromide emulsion (2 mol % of iodine) was prepared using a controlled double run method. This raw emulsion was a monodisperse emulsion with a cubic crystal habit, an average grain size of 0.25 μm, and 95% by weight of grains within 30% of the average grain size. After precipitating and washing with water, add gelatin and adjust the pI to 8.
0, pAg was adjusted to 5.0, and potassium chloroaurate 2''
f/mole AJ was added and heated at 60C for 2 hours. Then pAJ was adjusted to 8.5. Adjust the pH to 5.0 IC and divide the sample into 350q/mole dimethine dye.
A! ' was added.

Furthermore, Pinacryptol Yellow 200 Cape/mol
eAJ25- was added, a hardener and a surfactant were added, and the mixture was coated on a paper support laminated with subbed polyethylene at a coating weight of 3.7 g/- in terms of silver nitrate. After drying, each sample was cut to an appropriate size and exposed through a wedge with a density difference of 0.15.
It was developed for 90 seconds at 20C using a developer, fixed using an acidic fixer, washed with water, and dried. Table 1 was obtained as a result of concentration measurement.

S in the table is a value measured at an optical density of 0.75, and is expressed as a relative value with the blank value being 1.0.

γ represents the slope of the straight line between concentrations 0.5 and 1.5,
Dmin represents the minimum concentration.

26-Table 1 Photographic Properties of Each Sample As is clear from Table 1, the dimetine dye used in the present invention has excellent sensitization, provides high-contrast photographic properties, and has a low minimum density. Therefore, by using the dimetine dye of the present invention, it is possible to obtain a direct positive silver halide photographic light-sensitive material with high sensitivity and high contrast.

Example 2 A silver iodobromide emulsion (
2 mol% of iodine) was prepared. This raw emulsion is a monodisperse emulsion with a cubic crystal habit, an average grain size of 0.25μ, and 95% by weight of grains within 30% of the average grain size.After growing to 0.16μ, hexachloro Add potassium iridate 50 Mq/mole Ag,
After leaving at 0C for 20 minutes, double run was continued and 0.
It was grown to 25μ. After settling and washing with water, gelatin was added and the pH was adjusted to 6.5. Adjust the pAg to 6.2 and add 0.2 q/mo 1 e Ag of thiourea dioxide.
was added and aged at 60C for 1 hour.
11F/moleAg was added and heated at 60C for 1 hour. Then pA,i' was set to 8.5. Adjust the pH to 5.0, divide the sample, and add dimethine dye to 350”F/
Table 2 was prepared in the same manner as in Example 1 by adding moleAJ.
I got it.

29- Table 2 Photographic properties of each sample 30- As is clear from Table 2, the dimetine dye used in the present invention has a 2 to 5 times higher sensitization and is characterized by providing high-contrast photographic properties. Therefore, by using the dimetine dye of the present invention, it is possible to obtain a direct positive light-sensitive material with high sensitivity and high contrast.

131= 279-

Claims (1)

[Claims] (1) 5.6-cyclohydrobior2.1 h] 3-position of the isoquinoline ring and 1.2 of the 5- or 6-membered nitrogen-containing heterocycle.
3. A direct positive silver halide emulsion containing at least one dye whose 4- or 9-position is bonded by a dimethine chain.