JPS60123837A - Photographic silver halide emulsion - Google Patents

Abstract

PURPOSE:To prevent fog in high temp. development by using a specified benzotriazole deriv. for a photosensitive material processable in the light room. CONSTITUTION:The present silver halide emulsion layer capable of preventing fog at >=30 deg.C occurring in the case of using an org. desensitizer and 2-mercaptobenzoic acid, and not causing desensitization in processing in the light room is obtained by incorporating in a negative type fine grain silver halide photosensitive emulsion congt. at least 80mol% silver chloride, at least one of org. desensitizers each having a positive sum of the anode and cathode potentials in the polarograph, and at least one of 2-mercaptobenzoic acid compds., and a benzotriazole deriv. represented by the formula in which R is H, or a group of satd. or unsatd. aliphatic hydrocarbon, alicyclic, or aromatic hydrocarbon, or halogen, OH, alkoxy, COOH, or the like.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a silver halide photographic material, and more particularly to a silver halide photographic emulsion suitable for a light-sensitive material for bright room use.

In recent years, in the printing field, due to the complexity of printed matter and the development of scanners, there has been a desire to improve the efficiency of the return process. For this reason, a photographic film with an ultra-low sensitivity of about 10-3 to 10-5 has been developed compared to the conventional film for return, and can be handled in a bright room (white fluorescent film that excludes ultraviolet rays). It has begun to be put into practical use as a flexible film, ie, a photosensitive material for bright room use. - The performance required for such a light-sensitive material for use in a bright room is that it has high contrast and sufficient black density, can be handled for a long time in a bright room, and has high sensitivity to ultraviolet light sources. etc. However, the conventional photosensitive materials for use in bright rooms do not fully satisfy the above-mentioned performance, and there is a desire to develop improved photosensitive materials for use in bright rooms.

As a silver halide emulsion for photosensitive materials for bright room use, there is a method of using a large amount of rhodium as an inorganic desensitizer in silver halide mainly composed of silver chloride as described in JP-A-56-125734. Alternatively, it can be produced by a method using an organic desensitizer such as pinacryptol yellow, which is commonly used in direct positive silver halide emulsions. However, the present inventors have found that emulsions produced by any of the above methods cannot be used as light-sensitive materials for bright room use, and when handled under bright white light, the safety of the emulsions produced by any of the methods described above cannot be guaranteed. It was confirmed that there are some shortcomings.

Emulsions using rhodium salts in the polyolefin 1" cause significant capri under bright room light, while emulsions using organic desensitizers can withstand long periods of bright room light without producing capri as seen with rhodium salts. However, after image exposure, if the film is left under open room light for a short period of time before development, a noticeable decrease in sensitivity will occur.Of course, development will occur immediately after image exposure. It would be fine if they were processed, but because of the piles of dirt left over from printing, it is sometimes left under bright room light after image exposure, and there is little hope that the handling safety during printing can be improved. These can be improved by adding organic desensitizers and 2-mercaptobenzoic acids (Japanese Patent Application No. 58-54536). ) has the drawback of causing capri.Usually used anti-capri agents include 3-methylbenzothiazolium salt, 1-phenyl-2-tetrazoline 5-thione, 5-phenyltetrazole, 1-phenyl-5- Mercaptotetrazole and the like are undesirable because they promote desensitization at sublight temperatures.

Therefore, there has been a need for an anti-capri agent that prevents capri during high-temperature development and causes less desensitization in a bright room.゛Therefore,
The purpose of the present invention is to suppress the high temperature capri that occurs when an organic desensitizer and 2-mercaptobenzoic acids are used as a silver halide emulsion for light-sensitive materials in a bright room without impairing handling safety under bright room light. An object of the present invention is to provide an improved silver halide emulsion.

Other objects of the invention will be apparent from the following description.

As a result of extensive research to achieve the above object, the present inventors have found that a negative-working fine-grain silver halide emulsion containing at least 80 moles of silver chloride contains at least one organic desensitizer and at least one 2-mercaptobenzoic acid. Contains and the following (
1) It has been found that the above object can be achieved by a silver halide emulsion containing a benzotriazole derivative represented by the formula.

■ ■ (Here, R is hydrogen, saturated aliphatic hydrocarbon group, unsaturated aliphatic hydrocarbon group, alicyclic hydrocarbon group, aromatic hydrocarbon group,
These include halogen groups, hydroxyl groups, alkoxy groups, carboxylic acid groups, acyl groups, mercapto groups, amine groups, heterocyclic groups, and nitrile groups. ) In addition to thiosalicylic acid, the 2-mercaptobenzoic acids used in the present invention include those in which thiosalicylic acid is substituted with an alkyl group, an alkoxy group, an amino group, an acylamino group, a halogen atom, etc., and also those that form a mercapto group. For example, 8-acetylthiosalicylic acid, 8-methylcarbamoylthiosalicylic acid, 8-phenylcarbamoylthiosalicylic acid, 8-ethoxycarbonylthiosalicylic acid, and the like can be mentioned. These thiosalicylic acids are publicly known, for example, in JP-A-56-4145.

These thiosalicylic acids are preferably added to the silver halide emulsion, but they may also be added to the adjacent J- of the emulsion layer and diffused into the emulsion layer. The time of addition may be any time during the emulsion manufacturing process, and the amount of addition can be selected as appropriate within the range of approximately 20q to 5f per mole of halogen ratio. 'The organic desensitizer used in the present invention is one that is generally known to be used in direct positive silver halide emulsions. That is, the organic desensitizer used in the present invention is characterized by its polarographic half-wave potential, ie, its redox potential determined by polarography. Organic desensitizers useful in the present invention include those in which the sum of polarographic anodic and cathodic potentials is positive. Methods for measuring these redox potentials are described, for example, in US Pat. No. 3,501,307.

Specific examples of such organic desensitizers are described in numerous patent specifications and documents, all of which have the same effect in the present invention. 1961-20261, 1961-
26751, 13167-1972, 883-1973
3. 1974-8746, 1977-10197, 1977-37530, JP-A-48-24734, 1972
-84639, 1984-142525, US Special Aircraft No. 2
, No. 271,229, No. 2,541,472, No. 3,035,917, No. 3,062,651, No. 3,124,458, No. 3,326,687 ,
Compounds described in the specifications such as No. 3,671,254 can be used.

Benzotriazole used as an antifoggant has saturated aliphatic hydrocarbon groups, unsaturated aliphatic hydrocarbon groups, alicyclic hydrocarbon groups, aromatic hydrocarbon groups, halogen groups, hydroxyl groups, and alkoxy groups as substituents on the benzene ring. , carboxylic acid group,
It can have an acyl group, mercapto group, amine group, heterocyclic group, sulfonic acid group, nitrile group, etc.

Ordinary antifoggants cause greater desensitization in bright rooms, but
It is unexpected that these benzo) IJ azoles have no adverse effect on desensitization under light conditions. The amount of benzotriazole used is 91% per mole of silver halide.
The amount is 0 to 10 mol, preferably 10 to 10 mol.

In particular, it is preferable to include it in an emulsion. It may be further added to the processing liquid if necessary.

The silver halide emulsion used in the present invention has a silver halide emulsion of at least 80%
This is a negative emulsion containing Morch's silver chloride.

A negative emulsion is a normal type of silver halide emulsion that forms a negative image on a positive original, which is distinguished from a direct positive silver halide emulsion. Preferably, it is a silver halide emulsion containing 90 moles or more of silver chloride. Although it is preferable that silver iodide is not contained, it may be contained in a very small amount, for example, 0.2 molar grade, if necessary.

The silver halide emulsion used in the present invention is a fine-grain silver halide emulsion, preferably having an average grain size of about 0.05 to 0.3 μ. Further, it is preferable that 90% or more of the total number of particles have a particle size within a range of ±10% of the average particle size. The silver halide emulsion may be prepared by any known method such as copper mixing, reverse heating, or simultaneous mixing. Rhodium may or may not be included.

The silver halide emulsion obtained according to the present invention contains stabilizers, covering power improvers, irradiation inhibitors, film property improvers, surfactants, hardeners, matting agents, developing agents, etc. It can contain additives used in common photographic emulsions, and is coated on a known support. It may have other hydrophilic colloid layers such as a protective layer and an undercoat layer.

The photosensitive material for bright room use obtained by the present invention can be used mainly from light sources rich in ultraviolet light used in the printing field, such as mercury lamps,
Exposure is performed using an ultra-high pressure mercury lamp, metal halide, etc.

The light-sensitive material for bright room use obtained by the present invention can be safely handled for a long time under bright bright room light either before or after the above-mentioned exposure, and can be handled safely at high temperatures. There is little fog in the development process.

Example 1 Silver halide was precipitated in a conventional manner using 100 mol of adenine and 10 mol of rhodium chloride per mol of silver chlorobromide containing 95 mol% of silver chloride, and physical ripening was performed to determine the average grain size. An emulsion with a narrow particle size distribution of 0.2 μm was obtained. After desalting and redissolving this emulsion, Pinacryptol Yellow was added as an organic desensitizer at a concentration of 500 μm per mole of silver halide.
and thiosalicylic acid (400 μm), a hardener and a surfactant were added, and the mixture was coated on a polyester film with a gelatin solution for a protective layer to give a silver thickness of 3.5° and dried (blank sample).

Next, the above emulsion was added with 3-methylbenzothiazolium salt, 1-
Phenyl-2-tetrazoline-5-thione, 5-phenyltetrazole, 1-phenyl-5-mercaptotetrazole, and benzotriazole are used as antifoggants at a concentration of 200 μm to 1.0 μm per mole of silver halide. Ov was added and coated under the same conditions as the blank sample.

Two copies of each of these samples were exposed using a bright room printer through high-quality film.

One was processed under yellow safelight and the other was processed under 50
It was treated after being left for 30 minutes with a 0 Lux ultraviolet light removed fluorescent knife.

Development was performed at 35° C. for 23 seconds using a commercially available developer containing phenidone and hydroquinone as developing chemicals, followed by fixation and drying.

The sensitivity of the sample that had not been exposed to a white fluorescent lamp was set to 100, and the sensitivity of the sample after 30 minutes of exposure to a white fluorescent lamp was used as a guideline for handling in a bright room. In other words, it can be said that the higher the sensitivity φ after exposure with a fluorescent knife, the better.

These results are shown in Table ■ along with the Capri values.

Table I As shown in Table 2, benzotriazole (invention) has less desensitization in a bright room and eliminates development fog at high temperatures. On the other hand, other anti-capri agents are unsuitable because of their desensitization in a bright room.

Example 2 Next, various benzotriazole derivatives were tested.

The conditions are the same as in the first embodiment. Table 2 shows these results.
Shown below. Note that all f substituents are at the 5-position.

Table 2 As shown in Table 2, the benzotriazole derivatives do not cause desensitization in a bright room, and do not cause blur or blur even when developed at high temperatures. Such usefulness can be said to be unique among many antifoggants.

Claims (1)

[Claims] (i) A negative fine-grain silver halide photographic emulsion containing at least 80 mol of silver chloride is provided with at least one layer each of an organic desensitizer and a 2-mercaptobenzoic acid whose sum of polarographic cathode potential and cathode potential is positive; A silver halide photographic emulsion characterized by containing a benzotriazole derivative.