JPS6143702B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention is non-photosensitive under normal light, but can be imparted with photosensitivity by heating.
The present invention also relates to improvements in dry image forming materials (hereinafter generally referred to as non-photosensitive materials) that allow images to be obtained only by dry processing. More specifically, the present invention relates to improvement in emulsion stability during production and improvement in sensitivity and biostability of the resulting image forming material. Conventionally used silver halide photosensitive materials require complicated steps for image formation, and therefore considerable skill is required to obtain good results. Therefore, research has been carried out on photosensitive materials that can simplify the image forming process, and silver salt based photosensitive materials are made of an organic silver salt oxidizing agent, a silver ion reducing agent for reducing silver ions, and a catalytic amount of silver halide. has been proposed as a photosensitive material in which images can be obtained only by dry processing. However, this new photosensitive material is also photosensitive under normal light, and has the drawback that the film cannot be manufactured in a bright room and the film cannot be handled in a bright room. Therefore, normally non-photosensitive photosensitive materials have been proposed, but they have drawbacks such as insufficient biostability, and no material that can be put to practical use has yet been provided. As described in Japanese Patent Application No. 52-28088, normally non-photosensitive materials using iodine molecules have practical sensitivity, excellent biostability, and even without antifoggants. This is an excellent product with significantly less fog in exposed areas. However, in the manufacturing process of light-sensitive materials, there was a problem in the stability of the emulsion, which made it difficult to coat. The inventors of the present invention have conducted intensive research on new photosensitive materials with the aim of providing a normally non-photosensitive material that can be put to practical use. discovered a light-sensitive material and an emulsion composition with improved stability,
The present invention has been accomplished. The dry imaging material of the present invention comprises (i) a non-photosensitive organic silver salt oxidizing agent, (ii) an iodine molecule, (iii) diphenylpromemethane, (iv) a film-forming binder, and
(v) A reducing agent for silver ions. In addition, in order to improve the stability of the emulsion, at least the above component (i),
(ii), (iii) and (iv) are mixed and stirred in a suitable dispersion medium,
It is preferable to form a suspension of the organic silver salt oxidizing agent by dissolving the above components (ii), (iii) and (iv) in a dispersion medium. By using diphenylpromethane in combination with iodine molecules, a normally non-photosensitive photographic material with improved sensitivity and biostability can be obtained.Furthermore, by using diphenylpromethane and iodine molecules together in the emulsion manufacturing process, emulsion An improvement in stability is also achieved at the same time. As non-photosensitive organic silver salt oxidizing agents suitable for the present invention, silver salts of long chain fatty acids, such as silver salts of stearic acid, salts of behenic acid, and the like are particularly useful. However, other non-photosensitive silver salts such as silver saccharate, silver benzotriazole, etc. can also be used. The amount of these organic silver salts used is approximately 0.1 to 50
g/m ² , preferably 1 to 10 g/m ² . Even if the iodine molecule is used as it is,
Molecular complexes of iodine with other compounds, for example, in the form of complexes of iodine molecules with p-dioxane, or alternatively in the Journal of American Chemical Society (J. Am. Giem.
It may be used in the form of a complex containing an iodine molecule, such as 9-iodide triphenyl phosphite, the synthesis of which is described in J. Soc., Vol. 75, p. 3145 (1953). The iodine molecule is relative to the organic silver salt oxidizing agent used.
0.5-20 mol% is preferred. A suitable amount of diphenylbromomethane is 0.5 to 20 mole percent based on the organic silver salt oxidizing agent. Examples of the film-forming binder include polyvinyl butyral, polyvinyl formal, polymethyl methacrylate, cellulose acetate, polyvinyl acetate, cellulose acetate propionate, cellulose acetate butyrate, gelatin, and polystyrene. Two or more of these can be used as a mixture. Suitably, these amounts are about 10:1 to 1:10 by weight relative to the organic silver salt oxidizing agent. Reducing agents for silver ions that are particularly suitable for the present invention include inhibited phenols in which a sterically bulky group is bound to the carbon adjacent to the carbon to which the hydroxyl group is bound, thereby sterically inhibiting the hydroxyl group. For example, 2,6-di-t-butyl-4-methylphenol, 2,2'-methylenebis-(4-methyl-
6-t-butylaphenol), 2,2'-methylenebis-(4-ethyl-6-t-butylphenol), 2,4,4-trimethylpentylbis-(2
-hydroxy-3,5-dimethylphenyl)-methane, 2.5-di-t-butyl-4-methoxyphenol, and the like. In addition, reducing agents for silver salts such as hydroquinone, 2.5-dimethylhydroquinone, chlorohydroquinone, p-aminophenol, methylhydronaphthalene, phenidone, methyl gallate, p-phenylphenol, bisphenol A, 2,4-dihydroxy Benzoic acid, p-methoxyphenol can also be used. The amount of the reducing agent used is 0.1 to 200% by weight, preferably 1 to 100% by weight based on the amount of the organic silver salt oxidizing agent used.
% by weight. In addition to the above-mentioned components, improving components such as an image intensifying agent for silver images, an antifogging agent, and a background darkening inhibiting agent can be included, if necessary. Image intensifiers for silver images include phthalazinone, phthalimide, succinimide, zinc acetate,
Examples include cadmium acetate. A suitable amount of these is 0.01 to 1 mol per 1 mol of the organic silver salt oxidizing agent. Furthermore, examples of the background darkening inhibitor include tetrabromobutane, hexabromocyclohexane, tribromoquinaldine, and the like. The appropriate amount of these is about 2.5 to 14 mol % based on the organic silver salt oxidizing agent. In addition, in the dry image forming material of the present invention,
Although a practically usable image forming material can be obtained without using an antifogging agent, an antifogging agent may be added when further antifogging is required. For example, when mercury acetate is used as an antifoggant, a remarkable effect can be exerted by adding a small amount of 0.03 to 4 mol % to the organic silver salt oxidizing agent. A preferred method for producing the dry image forming material of the present invention is shown below. (i) A non-photosensitive organic silver salt oxidizing agent is uniformly dispersed in a suitable dispersion medium, and at least (ii) iodine molecules, (iii) diphenylpromethane and ( iv) Add the film-forming binder and mix and stir to combine these (ii), (iii) and (iv).
)
A suspension of an organic silver salt oxidizing agent is prepared by dissolving the components. As a dispersion medium, toluene, xylene,
Organic solvents include acetone, methyl ethyl ketone, methyl butyl ketone, ethyl acetate, ethylene glycol monoethyl ether, methanol, and ethanol. (v) The reducing agent for silver ions is the above components (i), (ii),
It may be added to a suspension of an organic silver salt oxidizing agent together with (iii) and (iv), or it may be laminated and coated on a layer coated with the suspension to form a dry image forming material. You may. The resulting composition is coated onto a support such as polyethylene film, cellulose acetate film, polyester film, paper, etc. by various methods well known in the art. The thickness of the coating when dry is 1 to 100 microns, preferably 3 to 20 microns. Drying is performed by air drying at room temperature. All operations can be performed in a bright room. The image forming material of the present invention thus prepared is non-photosensitive under normal room light and can be handled in a bright room. Next, photosensitivity can be imparted by heating a desired portion. The heating conditions are usually preferably in the range of 90 to 200°C. The higher the heating temperature, the shorter the heating time. A visible image is obtained by imagewise exposing the portion to which photosensitivity has been imparted by heating, and then performing heat development. Heat development is usually 90~
Preferably it is carried out at a temperature range of 200°C. The heat development time is usually longer than the preheating time for imparting photosensitivity. In this way, visible images can be recorded only in desired areas, and the latest information can be additionally recorded in other areas. EXAMPLES The present invention will be explained in detail below with reference to Examples, but the present invention is not limited to these Examples. Example 1 A uniform silver behenate suspension was prepared by adding 3 g of silver behenate to 22 g of a toluene-methyl ethyl ketone mixture (weight ratio 1:2) and ball milling for about 18 hours. To 15 g of silver behenate suspension, the following components [] were sequentially added at room temperature (approximately 20°C) with stirring and dissolved to produce a pale yellow silver behenate emulsion. 5 minutes after stirring the emulsion and 3 hours after stirring the emulsion, 100μ
It was applied evenly through the orifice and air-dried at room temperature. Ingredients [] Methyl ethyl ketone solution of polyvinyl butyral (10% by weight) 13g Iodine (finely ground with a pestle) 140mg Diphenylbromomethane 50mg Next, as a second layer, a composition consisting of the following ingredients [] was added to the first layer, respectively. An imaging material was prepared by uniformly coating the layer through a 75μ orifice and air drying at room temperature. The corresponding image forming materials 5 minutes and 3 hours after stirring the emulsion are referred to as material A and material A', respectively. Ingredients [] Cellulose acetate 6.3 g 2,2'methylenebis(4-ethyl-6-t-butylphenol) 3.5 g Phthalazinone 1.2 g Acetone 83 g Material A except that diphenylbromomethane was removed from component [] as a comparative example. And image forming materials prepared in the same manner as material A' are referred to as comparative material B and comparative material B'. Dry image forming materials A, A', B, and B' were heated in a dark room on a hot plate at 100°C for 5 seconds to impart photosensitivity, and then passed through a 21-step step tablet (manufactured by Kodak) and heated at 300 W. 1 with a tungsten lamp
Exposure for seconds. After that, a black negative image was obtained by heating on a hot plate at 120°C for 15 seconds. The reciprocal of the exposure required to obtain an optical density 0.5 greater than the optical density of the unexposed area (ODmin) is a measure of sensitivity. Biostability was determined by irradiating the image forming material with a 200,000 lux Xe lamp for 30 minutes, and then forming an image under the same operating conditions as above. The results are shown in Table 1. The sensitivity is expressed as a relative value with respect to that of Comparative Material B before irradiation with the Xe lamp, which is taken as 1. From the results in Table 1, the results of the present invention on emulsion stability, sensitivity, and biostability are clear.

[Table] Comparative Example 1 Tetraethylammonium iodide 50 was used instead of iodine in the components [ ] in Example 1.
Image forming material B was prepared under exactly the same conditions except that the amount was changed to mg. After further stirring the above emulsion for 3 hours, a film E' was prepared in the same manner as Material E. The properties of comparative materials E and E' are shown below. However, various conditions such as relative sensitivity and Xe lamp irradiation conditions are
This is exactly the same as Example 1.

[Table] Material E has narrower tolerance of developing conditions than material A of Example 1, and material A shows almost no increase in fog even when developed at 130°C for 10 seconds.
ODmin=0.07, whereas comparative material E
It increased to ODmin=0.12. Example 2 To 15 g of the silver behenate suspension in Example 1, the following components [] were sequentially added at room temperature with stirring and dissolved to produce a pale yellow silver behenate emulsion. As in Example 1, after 5 minutes and 3 hours of stirring the emulsion, it was applied uniformly onto a 100 .mu. thick polyester film through a 100 .mu.m orifice and air-dried at room temperature. The materials for which the emulsion was stirred for 5 minutes and 3 hours were designated as Material C and Material C', respectively. Ingredients [] Polyvinyl butyral in methyl ethyl ketone 13 g solution (10% by weight) Mercury acetate in methanol solution (5 mg/3 c.c.) 0.3 cc Iodine 30 mg Diphenylbromomethane 13 mg Phthalazinone 10 mg 2,2 methylene bis(4 -ethyl-6-t-butylphenol) 25 mg As a comparative example, materials prepared in the same manner as Material C and Material C' except that diphenylbromomethane was removed from component [] were used as Comparative Material D and Comparative Material
Let it be D′. The imaging process, sensitivity measures, and biostability tests were as in Example 1. The results are shown in Table 2.

[Table] From the results in Table 2, the effects of the present invention on emulsion stability, sensitivity, and biostability are clear. Example 3 To 15 g of the silver behenate suspension in Example 1, the following components [] were sequentially added at room temperature with stirring and dissolved to produce a silver behenate emulsion. After stirring the emulsion for 5 minutes, it was applied uniformly onto a 100 .mu. thick polyester film through a 100 .mu. orifice as in Example 1 and air-dried at room temperature. Ingredients [] Methyl ethyl ketone solution of polyvinyl butyral (10% by weight) 13g Iodine (finely ground with a pestle) 140mg Next, as a second layer, a composition consisting of the following ingredients [] was uniformly poured over the first layer through a 75μ orifice. An image-forming material was prepared by coating the film on the substrate and air-drying it at room temperature. Ingredients [] Cellulose acetate 6.3g Diphenylbromomethane 0.1g 2,2'-methylenebis(4-ethyl-6-t-butylphenol) 3.5g Phthalazinone 1.2g Acetone 83g Image forming process, sensitivity scale, biostability The properties test was carried out in accordance with Example 1. The results are shown in Table 3.

[Table] When compared with the results of Comparative Material B of Example 1, the effects of the present invention on sensitivity and biostability are obvious.

Claims (1)

[Scope of Claims] 1 (i) a non-photosensitive organic silver salt oxidizing agent, (ii) an iodine molecule, (iii) diphenylpromethane, (iv) a film-forming binder, and (v) silver and a reducing agent for ions. 2 At least (i) a non-photosensitive organic silver salt oxidizing agent, (ii) molecular iodine, (iii) diphenylpromemethane, and (iv)
A film-forming binder was mixed and stirred in a dispersion medium, and the above-mentioned iodine molecules, diphenylpromemethane, and a film-forming binder were dissolved in a non-photosensitive organic silver salt oxidizing agent suspension. The dry image forming material according to claim 1, characterized in that: