JP2002131865A - Photothermographic recording material improving photosensitivity - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a means improving the photosensitivity of a photothermographic recording material, provide the photothermographic recording material and also provide an aqueous dispersing solution used for the same. SOLUTION: The aqueous dispersing agent contains a binder or a surfactant, a substantially non-photosensitive and substantially water-insoluble organic silver salt and a photosensitive silver halide, and an aqueous emulsion further contains a sensitizer selected from the group consisting of tin bromide (II), an aminoiminomethanesulfinic acid, an aqueous salt of H3PO3, an aqueous salt of H3PO2, an aqueous salt of SO32-, and an aqueous salt of HSO3-; a method of preparing the same; and two requirements: (i) a light addressable heat-developable element contains a substantially non-photosensitive and substantially water-insoluble organic silver salt, a reducing agent having the relation of thermal action with the substantially non-photosensitive and substantially water-insoluble organic silver salt, the photosensitive silver halide and the binder; (ii) the photothermographic recording material coating the aqueous dispersing solution.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

FIELD OF THE INVENTION The present invention relates to an aqueous dispersion of a substantially non-light-sensitive organic silver salt and a light-sensitive silver halide, and to a photothermographic recording material prepared therefrom.

[0002]

BACKGROUND OF THE INVENTION SPSE Handbook of P
photographic Science and E
nginering, edited by Wood
lief Thomas, Wiley-Intersc
ence, New York (1973), page
No. 422 states that compounds such as stannous salts, sodium bisulfite and silane can reduce silver halide in grains.

[0003] The Theory of the P
photographic Process Fourt
h Edition, edited by T.H. H. J
ames, Eastman Kodak (1977),
pages 151-152 discuss silver halide emulsion reduction sensitization. According to James, the chemicals studied for this include stannous chloride, hydrazine, ethanolamine and aminoiminomethanesulfinic acid. Furthermore, silver digestion (silver digest)
low pAg using inert gelatin, also called ionic)
Sensitization provides one type of reduction sensitization.

[0004] EP-A 911 692 discloses the potential of reduction sensitization of silver halide for use in photothermographic recording materials, for which ascorbic acid, thiourea dioxide, stannous chloride, amino Disclosed are iminomethanesulfinic acid, hydrazine derivatives, borane compounds, silane compounds and polyamine compounds. In addition, it can perform reduction sensitization by ripening the emulsion while maintaining the pH of the emulsion at 7 or higher, or the pAg at 8.3 or lower, and also the formation of silver ions during grain formation. Single addition port (single addition port
It discloses that reduction sensitization can be performed by introducing (ion).

[0005] EP-A 962 812 discloses the possibility of reduction sensitization of silver halide for use in photothermographic recording materials, for which stannous chloride, aminoiminomethanesulfonic acid, hydrazine derivatives , Borane compounds, silane compounds, polyamines, ascorbic acid and thiourea dioxide. Further, it can be reduced sensitized by ripening the emulsion while keeping the pH of the emulsion at 7 or higher, or its pAg at 8.3 or lower, and also during grain formation. It is disclosed that reduction sensitization can be performed by introducing a single addition portion of silver ion.

US Pat. No. 5,965,346 discloses the potential for reduction sensitization of silver halide for use in photothermographic recording materials, for which ascorbic acid, thiourea dioxide, stannous chloride, It discloses aminoiminomethanesulfinic acid, hydrazine derivatives, borane compounds, silane compounds and polyamine compounds. Furthermore, it can be reduced sensitized by ripening the grains while keeping the emulsion at a pH of 7 or higher, or at a pAg of 8.3 or lower; It is disclosed that reduction sensitization can also be performed by introducing a single addition portion of.

US Pat. No. 6,083,680 discloses the potential of reduction sensitization of silver halide for use in photothermographic recording materials, for which stannous chloride, aminoiminomethanesulfonic acid, hydrazine It discloses derivatives, borane compounds, silane compounds, polyamines, ascorbic acid and thiourea dioxide. Further, it can be reduced sensitized by ripening the emulsion while keeping the pH of the emulsion at 7 or higher, or its pAg at 8.3 or lower, and also during grain formation. It is disclosed that reduction sensitization can be performed by introducing a single addition portion of silver ion.

[0008] A major problem in developing photothermographic recording materials is their lower sensitivity than silver halide. By switching to a photothermographic recording material, the environmental benefits of eliminating the need for wet development of silver halide emulsions are obvious. Furthermore, coating photothermographic recording materials from aqueous media has significant environmental and economic benefits over solvent media, such as a significant reduction in solvent spill, no risk of solvent vapor explosion, plant availability, and the like. Thus, a photo-addressable (photo-
Addressable means for enhancing the photosensitivity of the heat developable element are desirable.

[0009]

OBJECTS OF THE INVENTION It is therefore one object of the present invention to provide a means for improving the photosensitivity of a photothermographic recording material coated from an aqueous medium.

It is therefore still another object of the present invention to provide a photothermographic recording material with enhanced photosensitivity, wherein the photo-addressable heat developable element is coated from an aqueous medium.

[0011] It is therefore another object of the present invention to provide an aqueous dispersion for use in providing a photothermographic recording material with enhanced photosensitivity wherein the photo-addressable heat developable element is coated from an aqueous medium. It is to be.

Further objects and advantages of the present invention will become clear from the description hereinafter.

[0013]

SUMMARY OF THE INVENTION Reduction sensitization of silver halide is a well-known method for improving the sensitivity of silver halide emulsions, so that those skilled in the art will recognize that a known reducing agent may be used in such methods. It would be expected that silver halide could be used for reduction sensitization of photothermographic emulsions used as photosensitizers. However, many of the well-known reduction sensitizers from the silver halide emulsion method have prohibitive fog when used in aqueous dispersions of substantially non-light sensitive silver salts and light sensitive silver halide. And has been found to produce an forbidden increase in exposure S required to achieve an optical density of 1.0 above the fog level, i.e., an forbidden decrease in light sensitivity. However, a limited group of reducing agents that achieve sensitization in such aqueous dispersions have been identified.

The above object is to provide a binder or surfactant, a substantially non-photosensitive and substantially water-insoluble organic silver salt and a photosensitive silver halide, wherein the aqueous emulsion further comprises tin bromide. (II), aminoiminomethanesulfinic acid, H ₃ P
Water-soluble salts of O _3, water-soluble salts of H ₃ PO _2, water-soluble SO ₃ ^2-salt and water-soluble HSO ₃ ^- by aqueous dispersion which comprises a sensitizer selected from the group consisting of salt Is achieved.

The above objects are: (i) preparing a dispersion of the photosensitive silver halide in an aqueous medium; (ii) adding to the dispersion prepared in step (i), tin (II) bromide, amino imino sulfinic acid, H ₃ water-soluble salts of PO _3, H ₃ water-soluble salts of PO _2, water-soluble SO ₃ ^2-salt and water-soluble HSO ₃ ^- at least one sensitizer selected from the group consisting of salt (I
ii) a method for preparing an aqueous dispersion comprising the step of adding a substantially non-photosensitive and substantially water-insoluble organic silver salt.

The above objects further include a support and a photo-addressable heat developable element, wherein the photo-addressable heat developable element has two requirements: (i) a photo-addressable heat developable element. Is a reduction in a thermally operative relationship therewith for a substantially non-photosensitive and substantially water-insoluble organic silver salt, a substantially non-photosensitive and substantially water-insoluble organic silver salt And (ii) the photo-addressable heat developable element comprises a layer obtainable by coating the aqueous dispersion described above on a support. It is also realized by a filling photothermographic recording material.

The above object is to provide a substantially non-photosensitive and substantially water-insoluble organic silver salt, a reducing agent for a substantially non-photosensitive and substantially water-insoluble organic silver salt. and light containing the binder - for improving the sensitivity of the photothermographic recording materials with photo-addressable thermally developable element, tin bromide (II), aminoiminomethanesulfinic acid, water-soluble salts of H ₃ PO ₃ , water-soluble salts of H ₃ PO _2, water-soluble SO ₃ ^2-salt and water-soluble HSO ₃ ^- is also realized by the use of a sensitizing agent selected from the group consisting of salts.

Further preferred embodiments of the invention are disclosed in the dependent claims.

[0019]

Detailed Description of the Invention Definitions The term aqueous for the purposes of the present invention refers to water and at most 4
0%, preferably up to 20% by volume, of a water-miscible organic solvent such as alcohols such as methanol, ethanol, 2-propanol, butanol, iso-amyl alcohol, octanol, cetyl alcohol and the like; glycols such as ethylene Glycol; glycerin;
N-methylpyrrolidone; methoxypropanol; and mixtures with ketones such as 2-propanone and 2-butanone.

Substantially non-photosensitive means that it is not particularly light sensitive but is resistant to darkening when exposed.

Substantially water-insoluble is 2 ° C. at 20 ° C.
Mean solubility in water less than mg / L.

Water solubility is at least 2 m at 20 ° C.
It means the solubility in g / L of water.

S: Photothermographic recording material is D
It is defined as the exposure at mJ / m ² that reaches an optical density of 1.0 above min. Thus, the lower the value of S,
High photosensitivity of photothermographic recording material.

As used herein, the UAg of an aqueous liquid is defined as a silver electrode having a purity of 99.99% in an aqueous liquid and a 10% KNO ₃
3M KC connected to liquid via salt bridge consisting of salt solution
1 defined as the potential difference at room temperature between a reference electrode consisting of an Ag / AgCl-electrode in solution.

By the term "heat solvent" herein is meant a plasticizer for the recording layer in the solid state in the recording layer at a temperature below 50 ° C., but at a temperature above 60 ° C. in the heated area. And / or a non-hydrolysable organic material that becomes a liquid solvent for at least one of the redox-reactants, eg, a reducing agent for a substantially non-photosensitive and substantially water-insoluble organic silver salt. Means

As used herein, thermally developable under substantially anhydrous conditions allows the reaction system to be in approximately equilibrium with water in the air, and water to induce or accelerate the reaction. In particular, or under the condition that the thermographic recording material is not supplied from the outside of the thermographic recording material, 80 ° C.
Means heating at a temperature of 250 ° C. Such conditions are described in T.W. H. James, "The Theory o
f the Photographic Processes
s, Fourth Edition, Macmilla
n 1977, page 374.

Aqueous Dispersion The present invention comprises a binder or surfactant, a substantially non-photosensitive and substantially water-insoluble organic silver salt and a photosensitive silver halide, wherein the aqueous emulsion further comprises bromide bromide. Tin (II), aminoiminomethanesulfinic acid, water-soluble salt of H ₃ PO ₃ , H ₃
PO ₂ water-soluble salt, water-soluble SO ₃ ^2- salt and water-soluble HSO ₃ ⁻
An aqueous dispersion characterized by containing a sensitizer selected from the group consisting of salts. Binders or surfactants are necessary to keep the substantially non-light sensitive and substantially water insoluble organic silver salt and light sensitive silver halide in suspension.

In a preferred embodiment of the aqueous dispersion according to the invention, the aqueous dispersion is further treated at 20 ° C. with 1 L of water.
It contains a water-soluble silver salt having a water-solubility of more than 0.1 g per unit. Since the improvement in photosensitivity depends on the ionic dissociation of the water-soluble silver salt in the aqueous medium, the water-solubility of the water-soluble silver salt mainly affects the preparation time of the aqueous dispersion.
Thus, the water-solubility of the water-soluble silver salt is preferably greater than 0.1 g / L of water at 20 ° C. In a preferred embodiment of the aqueous dispersion according to the invention, the amount of water-soluble silver salt added is at least one with respect to the amount of light-sensitive silver halide.
Mol%, and preferably at least 15 mol%. The amount of water-soluble silver salt is preferably also less than 80 mol% with respect to the amount of light-sensitive silver halide. The grain size of the photosensitive silver halide is preferably from 70 to 100 nm.

In a still further embodiment of the aqueous dispersion according to the present invention, the aqueous dispersion further comprises a substantially non-photosensitive and substantially water-insoluble reducing agent for organic silver salts.

Preparation of aqueous dispersion (i) Preparation of dispersion of photosensitive silver halide in aqueous medium
(Ii) adding tin bromide to the dispersion prepared in step (i);
(II), aminoiminomethanesulfinic acid, H_ThreePO_Three
Water-soluble salt of H_ThreePO_TwoWater-soluble salt, water-soluble SO_Three ^2-Salt
And water soluble HSO_Three ^-At least selected from the group consisting of salt
Adding one sensitizer; (iii) substantially non-photosensitive and
Adding a substantially water-insoluble organic silver salt
A method for preparing an aqueous dispersion is provided.

In a preferred embodiment of the process for preparing an aqueous dispersion according to the invention, the process further comprises the addition of a water-soluble silver salt having a water solubility of more than 0.1 g in 1 L of water at 20 ° C.

According to the method for preparing an aqueous emulsion according to the present invention,
The second silver salt can be dissolved in a small amount of a water-miscible organic solvent as an aqueous solution or added as a slurry in water, but in the latter case, the particles of the second silver salt are added to the aqueous emulsion. Must dissolve during preparation.

Reduction sensitizers The reduction sensitizers according to the present invention include tin (II) bromide, aminoiminomethanesulfinic acid, a water-soluble salt of H ₃ PO ₃ (phosphorous acid) and H ₃ PO ₂ (hypoxia). Water-soluble salt of phosphoric acid), water-soluble SO
₃ ^2- salts and water-soluble HSO ₃ ^- is selected from the group consisting of salts.
Preferred reduction sensitizers according to the present invention are: RS01 = tin (II) bromide = SnBr ₂ ; RS02 = aminoiminomethanesulfinic acid = formamidine-sulfinic acid = thioureadioxide = (NH ₂ ) ₂ C = SO
₂ ; RS03 = ammonium sulfite = (NH ₄ ) ₂ SO ₃ ;
RS04 = lithium sulfite = Li ₂ SO ₃ ; RS05 = sodium sulfite = Na ₂ SO ₃ ; RS06 = potassium sulfite = K ₂ SO ₃ ; RS07 = ammonium bisulfite = NH
₄ HSO ₃ ; RS08 = lithium bisulfite = LiHS
O ₃ ; RS09 = sodium bisulfite = NaHSO ₃ ; R
S10 = potassium metabisulfite = KHSO _3; RS11 = ammonium phosphite _{= (NH 4) 2 HPO 3} ; RS12 =
Lithium phosphite = Li ₂ HPO ₃ ; RS13 = sodium phosphite = Na ₂ HPO ₃ ; RS14 = potassium phosphite = K ₂ HPO ₂ ; RS15 = ammonium hypophosphite =
(NH ₄ ) H ₂ PO ₂ ; RS16 = lithium hypophosphite =
LiH ₂ PO ₂ ; RS17 = sodium hypophosphite = Na
H ₂ PO _2; RS18 = potassium hypophosphite = NaH ₂ P
O ₂ .

Water-Soluble Silver Salt In conventional photographic emulsions, adding a water-soluble silver salt to a dispersion of light-sensitive silver halide before coating results in photographic materials with very high fog levels, but surprisingly. Adding a silver salt having a water-solubility greater than 0.1 g / L of water to an aqueous dispersion of a substantially non-photosensitive and substantially water-insoluble organic silver salt and a light-sensitive silver halide, generally Further enhances the photosensitivity of a photothermographic recording material comprising a photo-addressable thermally developable element comprising a layer formed by coating an aqueous dispersion on a support, but made with it. It was found that the background density of the print had only a marginal effect.

The water-soluble silver salt in the aqueous dispersion according to the invention preferably has a solubility at 20 ° C. of more than 0.1 g / l of water, preferably a solubility of more than 1 g / l.

Suitable water-soluble silver salts according to the present invention include silver nitrate, silver acetate, silver propionate, silver sulfate, silver butyrate, silver isobutyrate, silver benzoate, silver tartrate, silver salicylate, silver malonate, succinic acid Contains silver and silver lactate, silver nitrate, silver acetate,
A water-soluble silver salt selected from the group consisting of silver lactate and silver sulfate is preferred.

The addition of a soluble silver salt to a dispersion of silver halide can result in an increase in UAg (= decrease in pAg = increase in free silver ion concentration), which can result in a partial reduction of the silver salt present. The provision of metallic silver nuclei thereby is known in silver halide photography. Such metallic silver nuclei enhance the level of fog in silver halide photographic materials. It is possible that a similar effect is the basis for the enhancement of sensitivity resulting from the addition of a water-soluble silver salt.

A substantially non-photosensitive and substantially water-insoluble organic silver salt A substantially non-photosensitive and substantially water-insoluble organic silver salt is any organic silver salt containing a heterocyclic nitrogen compound. It can also be a silver salt of an organic acid, for example silver benzotriazole or silver benzimidazole, but preferably silver of an organic carboxylic acid having as its organic group: aryl, aralkyl, alkaryl or alkyl. Salt. The aliphatic carbon chain preferably has at least 12 C-
Aliphatic carboxylic acids known as fatty acids having atoms, such as silver laurate, silver palmitate, silver stearate,
Silver hydroxystearate, silver oleate, silver behenate and silver arachidonic acid are preferred, and their silver salts are also referred to as "silver soaps". Silver salts of other organic carboxylic acids, such as described in GB-P 1,439,478, for example silver benzoate, and Research Disclos
ure 17029, but the Research
ch Disclosure 12542 and US
Use of a silver salt of an organic carboxylic acid other than a silver salt of an organic carboxylic acid substituted with a heterocyclic thione group as described in US Pat. No. 3,785,830 for forming a thermally developable silver image Can be. Combinations of substantially non-photosensitive and substantially water-insoluble organic silver salts can also be used in the present invention.

Aqueous dispersions of substantially non-photosensitive and substantially water-insoluble organic silver salts or mixtures thereof are disclosed in US Pat.
5,891,616 and EP-A 848286 and US 3,839,049.

Organic Reducing Agents Organic reducing agents suitable for the reduction of substantially non-photosensitive and substantially water-insoluble organic silver salt particles include aromatic di- and tri-hydroxy compounds; aminophenols;
L ^™ ; p-phenylene-diamine; alkoxynaphthols, for example 4-methoxy-1-naphthol described in US Pat. No. 3,094,41; pyrazolidine-3
-One type reducing agents such as PHENIDONE ^™ ; pyrazolin-5-one; indane-1,3-dione derivatives; hydroxytetronic acid; hydroxytetronimide; for example hydroxyl as described in US-P 4,082,901. Amine derivatives; hydrazine derivatives; and reductones, for example organic compounds containing at least one active hydrogen atom bonded to O, N or C as in the case of ascorbic acid; US-P
3,074,809, 3,080,254, 3,09
See also 4,417 and 3,887,378. Particularly suitable reducing agents are sterically hindered phenols, bisphenols, sulfonamidophenols and WO97
/ 04357.

It is also possible to use a combination of reducing agents which, when heated, become a reactive partner in the reduction of the silver salt of a substantially non-photosensitive organic carboxylic acid. For example, US
Combinations of sterically hindered phenols and sulfonyl hydrazide reducing agents as disclosed in US Pat. No. 5,464,738; trityl hydrazide and formyl-phenyl as disclosed in US Pat. No. 5,496,695.
Combinations of hydrazides; US-P 5,545,50
5, US-P 5.545.507 and US-P 5,
Combinations of trityl hydrazide and formyl-phenyl-hydrazide with various co-reducing agents as disclosed in US Pat. No. 558,983; US-P 5,545,515 and US-P 5,635,339. Combinations of such acrylonitrile compounds; and US-P
Combinations of 2-substituted malonodialdehyde compounds as disclosed in 5,654,130.

Binders for Photo-Addressable Heat Developable Elements The aqueous dispersions of the present invention and film-forming binders for use in the photo-addressable heat developable element are water-dispersible or water-soluble. Sex binders.

Suitable water-soluble film-forming binders are
Polyvinyl alcohol, polyacrylamide, polymethacrylamide, polyacrylic acid, polymethacrylic acid, polyethylene glycol, polyvinylpyrrolidone, proteinaceous binders such as gelatin, modified gelatin such as phthaloyl gelatin, polysaccharides such as starch, gum arabic and Dextran and water-soluble cellulose derivatives.

Suitable water-dispersible binders include any water-
Insoluble polymers, such as water-insoluble cellulose derivatives,
Polyurethanes, polyesters Polymers derived from polycarbonates and α, β-ethylenically unsaturated compounds, such as post-chlorinated polyvinyl chloride, partially hydrolyzed polyvinyl acetate, polyvinyl acetal,
Preferably a polyvinyl butyral and using a monomer selected from the group consisting of: vinyl chloride, vinylidene chloride, acrylonitrile, acrylamide, methacrylamide, methacrylate, acrylate, methacrylic acid, acrylic acid, vinyl esters, styrenes, dienes and alkenes. Homopolymers and copolymers; or mixtures thereof.

Preferred water-dispersible binders are sulfonates, sulfinates, carboxylate, phosphate, quaternary ammonium, tertiary sulfonium and quaternary sulfonium.
A water-dispersible film-forming polymer having a covalently bonded ionic group selected from the group consisting of primary phosphonium groups. Yet another preferred water-dispersible binder is 1
Water-dispersible film-forming polymers having moieties covalently bonded to one or more acid groups.

In the case of very small polymer particles, there is no clear detached transition between the polymer dispersion and the polymer solution, the smallest polymer particles being dissolved and the slightly larger ones being in the dispersion. Note that the result is

Also preferred are water-dispersible binders having crosslinkable groups, such as epoxy groups, aceto-acetoxy groups and crosslinkable double bonds. Preferred water-dispersible binders for use in the photo-addressable heat developable element of the present invention are polymer latexes as disclosed in WO 97/04355.

The above-mentioned binders or mixtures thereof are used together with waxes or "heat solvents", also called "thermal solvents" or "thermosolvents", which increase the reaction rate of the redox reaction at elevated temperatures. be able to.

Light-sensitive silver halide The light-sensitive silver halide used in the present invention may be a substantially non-photosensitive and substantially water-insoluble organic silver salt of from 0.1 to 0.1.
100 mole percent; preferably 0.2 to 80 mole percent; particularly preferably 0.3 to 50 mole percent; particularly preferably 0.5 to 35 mole percent; and especially within the range of 1 to 12 mole percent. Can be used.

The silver halide may be any photosensitive silver halide such as silver bromide, silver iodide, silver chloride, silver bromoiodide, silver chlorobromoiodide, silver chlorobromide and the like. it can. Silver halide can be in any form that is photosensitive, including but not limited to cubic, oblique, plate-like, tetrahedral, octagonal, etc., and can have epitaxial growth of crystals thereon. it can.

The silver halide used in the present invention may be a compound containing sulfur, selenium, tellurium, etc. or gold, platinum, palladium, iron, ruthenium, rhodium or sensitized with a specific reducing agent according to the present invention. It can be chemically sensitized using a chemical sensitizer such as a compound containing iridium or the like. Details of these methods can be found in H. Jam
s, "The Theory of the Photo
graphical Process ", Fourth
Edition, Macmilla Publishi
ng Co. Inc. , New York (197
7), Chapter 5, pages 149 to
169.

The particle size of the silver halide grains was determined by using a Moeller Tell in the sample containing the silver halide grains.
The sample can be sedimented on filter paper, which is submerged in the electrolyte along with a negative platinum needle-shaped electrode and a reference electrode. Needle the silver halide particles on the filter paper
The individual scans are slowly performed with shaped electrodes, and the silver halide grains are individually electrochemically reduced at the cathode.
This electrochemical reduction involves a current pulse, which is recorded as a function of time and integrated to obtain a charge transfer Q for the electrochemical reduction of silver halide grains, which is proportional to its volume. From their volumes, the equivalent circular particle size of each particle can be determined, from which the average particle size and size distribution can be determined.

Spectral Sensitizers The light-addressable heat developable element of the aqueous dispersion or photothermographic recording material according to the present invention optionally comprises a spectral sensitizer for silver halide suitable for the wavelength of the light source. It can be included with a color sensitizer, whose wavelength is in the near UV, visible part of the spectrum, e.g.
m, 670 nm, etc., or in the IR portion. Silver halide is optionally, especially in the case of sensitization to infrared radiation, in the presence of a so-called supersensitizer, cyanine,
It can be spectrally sensitized with various known dyes, including merocyanine, styryl, hemicyanine, oxonol, hemioxonol and xanthene dyes. Useful cyanine dyes include those having a basic nucleus, such as a thiazoline nucleus, an oxazoline nucleus, a pyrroline nucleus, a pyridine nucleus, an oxazole nucleus, a thiazole nucleus, a selenazole nucleus and an imidazole nucleus. Preferred useful merocyanine dyes have not only the above-mentioned basic nucleus but also an acid nucleus such as a thiohydantoin nucleus, a rhodanine nucleus, an oxazolidinedione nucleus, a thiazolidinedione nucleus, a barbituric acid nucleus, a thiazolinone nucleus, a malononitrile nucleus and a pyrazolone nucleus. Is included. Among the above-mentioned cyanine and merocyanine dyes, those having an imino group or a carboxyl group are particularly effective.

Supersensitizer According to the present invention, the aqueous dispersion and the photo-addressable heat developable element can further comprise a supersensitizer.
Preferred supersensitizers are selected from the group of compounds consisting of: mercapto compounds, disulfide compounds, stilbene compounds, organoborate compounds and styryl compounds.

Toner To obtain a neutral black image tone at relatively high densities and a neutral gray at relatively low densities,
The aqueous dispersion or photo-addressable heat developable element according to the present invention can contain one or more toning agents. The toning agent must be in thermal working relationship with the substantially non-photosensitive and substantially water-insoluble organic silver salts and the reducing agent therefor during the heat treatment.

Stabilizers and Antifoggants To increase shelf life and reduce fog, stabilizers and antifoggants such as phenyltribromo in aqueous dispersions and photo-addressable heat developable elements according to the present invention. Methyl sulfone, 4-methylphthalic acid and 2-mercapto-4-heptyl-oxadiazole can be introduced.

Light-Addressable Thermally Developable Element According to the present invention, a light-addressable thermal developable element has two requirements: (i) the light-addressable thermal developable element is substantially non-photosensitive. A substantially water-insoluble organic silver salt, a reducing agent in thermal working relationship with that for a substantially non-photosensitive and substantially water-insoluble organic silver salt, a photosensitive silver halide and And (ii) the photo-addressable heat developable element comprises a layer obtainable by coating an aqueous dispersion according to the present invention.

These two requirements are that the aqueous dispersion is a binder or surfactant, a substantially non-photosensitive and substantially water-insoluble organic silver salt, a photosensitive silver halide: tin bromide ( I
I), aminoiminomethanesulfinic acid, H ₃ water-soluble salts of PO _3, H ₃ water-soluble salts of PO _2, water-soluble SO ₃ ^2-salt and water-soluble HSO ₃ ^- sensitizing agent selected from the group consisting of salt Water-soluble silver salt optionally having a solubility in water of greater than 0.1 g / L at 20 ° C., substantially non-
It overlaps in that it can contain reducing agents, spectral sensitizers, supersensitizers, one or more stabilizers and binders for photosensitive and substantially water-insoluble organic silver salts. Would.

The photo-addressable heat developable element may comprise a single layer formed using the aqueous dispersion according to the present invention, or may comprise more than one layer, one of which may be aqueous. The dispersion is formed using a dispersion, and the other layers are other components necessary for image formation, for example, substantially non-
Photosensitive and substantially water-insoluble organic silver salts can contain reducing agents, binders, toning agents and one or more stabilizers. The reducing agent must be present in such a way that it can diffuse into the substantially light-insensitive and substantially water-insoluble particles of the organic silver salt and that the reduction can take place. The agent and one or more stabilizers must be able to interact with the substantially non-photosensitive and substantially water-insoluble organic silver salt and the reducing agent therefor.

The light-addressable heat developable element can also be coated with a protective layer.

Support The support for the photothermographic recording material according to the present invention can be transparent, translucent or opaque;
Preferably made of, for example, paper, polyethylene coated paper or transparent resin film, for example, cellulose ester,
Thin, flexible carriers made from, for example, cellulose triacetate, polypropylene, polycarbonate or polyester, for example polyethylene terephthalate. The support can be in the form of a sheet, ribbon or web. An undercoat layer can be subbed on the support. It can also be made from an opacifying resin composition.

Antihalation Dye The photothermographic recording material used in the present invention comprises:
It may also contain antihalation or acutance dyes that absorb light that has passed through the photosensitive heat developable photographic material, thereby preventing its reflection. Such dyes can be incorporated into the photo-addressable thermally developable element or any other layer of the photothermographic material of the present invention.

Antistatic Layer In a preferred embodiment of the photothermographic recording material of the present invention, an antistatic layer is applied to the outermost layer.

Surfactants and Dispersants Surfactants are surfactants that are soluble compounds that reduce the interfacial tension between liquids and solids. The thermographic and photothermographic recording materials of the present invention can contain anionic, non-ionic or amphoteric surfactants. Suitable dispersants are natural polymeric substances, synthetic polymeric substances and finely divided powders, for example finely divided non-metallic inorganic powders such as silica.

Coating The coating of any of the layers of the photothermography of the present invention may be a Modern Coating and Dry
ing Technology, edited by
Edward D. Cohen and Edgar
B. Gutoff, (1992) VCH Public
shers Inc. , 220 East 23rd
Street, Suite 909 New York
k, NY10010, USA.

Photothermographic Printing The photothermographic recording material according to the present invention can be exposed using radiation at a wavelength between the X-ray wavelength and the 5 micron wavelength, and the image is finely focused.
sed) light sources, for example CRT light sources; UV, visible or IR wavelength lasers, for example He / Ne lasers or IR-laser diodes, for example emitting at 780 nm, 830 nm or 850 nm;
Pixel-by-pixel exposure using, for example, one that emits at 659 nm; or using suitable illumination, eg, U
Obtained by direct exposure to the object itself or an image therefrom using V, visible or IR light.

For the thermal development of image-wise exposed photothermographic recording materials according to the present invention, any which makes it possible to uniformly heat the recording material to the development temperature within a time acceptable for the relevant application. Types of heat sources,
For example, contact heating, radiation heating, microwave heating, or the like can be used.

INDUSTRIAL USE Photothermographic recording materials according to the invention can be used, for example, in black-light inspection methods operated with light boxes.
Creation of transparency in the medical diagnostic field where imaged transparency is widely used,
And can be used both for the production of reflective prints, for example in the field of hard copy graphics and in microfilm applications. For such applications, the support will be transparent or opaque, ie, have a white light reflecting surface. If a transparent base is to be used, the base can be colorless or colored with a blue color, for example for medical diagnostic applications.

In the following, the invention is described by means of examples 1 to 18 of the invention and comparative examples 1 to 15, in which all percentages are by weight unless otherwise stated. The following unspecified components were used: Photo-addressable thermally developable element: AgB = silver behenate Reducing agent for AgX without sensitization: R01 = dimethylaminoborane = (CH ₃ ) ₂ NH. B
H _3; ● R02 = iron sulfate _{(II) = FeSO 4; ●} R03 = 1- formyl, 2-phenylhydrazine; ● R04 = ascorbic acid; ● R05 = ethanolamine = HOC ₂ H ₄ NH ₄ binding agent: R16875 = R16875 type, ROUSSE
Phthaloyl gelatin from LOT; K7598 = 759
Type 8, AGFA-GEVAERT GELATENEF
Calcium-free gelatin from ABRIKE; surfactant Nr. 1 = MARLON ^™ A-396, Hue
sodium alkyl-phenylsulfonate from ls;
Surfactant Nr. 2 = ERKANTOL ^™ BX, BA
Sodium diisopropyl-naphthalenesulfonate from YER; surfactant Nr. 3 = ULTRAVON ^TM
W, supplied as 75-85% strength sodium aryl sulfonate by CIBA-GEIGY; LOWINO
X22IB46 = CHEM. 2-propyl-bis (2-hydroxy-3,5-dimethylphenyl) methane from WERKE LOWI; SENSI 01 =

[0070]

Embedded image

TA01 = phthalazine; STABI 01 =

[0072]

Embedded image

STABI 02 = 4-methyl-phthalic acid; and STABI 03 = phenyltribromomethylsulfone. Anti-halation layer: K7598 = 7598 type, AGFA-GEVAERT
GELATENEFABRIKE vol. KOEP
Calcium-free gelatin from FF &SOEHNE; KIESELSOL 300F = 30% aqueous dispersion of colloidal silica from BAYER; and LATEX 01 = poly (ethyl acrylate) latex. ANTIHALO 01

[0074]

Embedded image

Protective layer: K7598 = 7598 type, AGFA-GEVAERT
GELATENEFABRIKE vol. KOEP
Calcium-free gelatin from FF &SOEHNE; surfactant Nr. 4 = Perfluoro-octanoic acid ammonium salt.

[0076]

EXAMPLES Examples 1 to 6 of the present invention and Comparative Example 1
Preparation of silver behenate dispersion in aqueous medium in absence of organic solvent using single jet method and aqueous dispersion of silver behenate used in Examples 1 to 6 of the present invention and Comparative Examples 1 and 2 Prepared as follows: i) In a 200 mm diameter vessel at 80 ° C.
10% solution of surfactant nr1 in an amount of 549 mL and 6
At a temperature of 80 ° C. in 62 g of deionized water, 80
Disperse 136.2 g (0.4 M) of behenic acid while stirring at 310 rpm with a diaphone stirrer of 80 mm diameter; ii) then stir 80 mm diameter Typhoon in a 200 mm diameter vessel at 80 ° C. 310 using machine
While stirring at rpm, 188 mL of a 2M aqueous solution of sodium hydroxide is added over 10 minutes to obtain a clear solution containing essentially sodium behenate; iii) then into a 200 mm diameter vessel at a temperature of 80 ° C. Of a 1 M aqueous solution of silver nitrate while stirring at 310 rpm using a Typhoon stirrer of 80 mm diameter.
Add 60 mL over 4.5 minutes to completely convert the sodium behenate to silver behenate.

The resulting aqueous silver behenate dispersion is 8.15
Wt% silver behenate and 2.78 wt% surfactant 1
And then desalted using ultrafiltration to give 22.3
It was concentrated to an aqueous dispersion containing 7% by weight of silver behenate.

Production of Photosensitive Silver Halides Determined in deionized water using the Moeller Teller method (see above for details).
Silver bromide having a weight average particle size of 3 nm was 11.44.
A silver halide emulsion containing 5.17% by weight of R16875 as a dispersant and 5.17% by weight of a silver halide emulsion at 50.5.degree. H. James, “The Theory of
the Photographic Procedures
s ", Fourth Edition, Macmill
an Publishing Co. Inc. , New
York (1977), Chapter 3, page
It was produced using a conventional silver halide production method as described in es88-104.

Preparation of Aqueous Dispersion 26.2 g of K7598 were added to 150 g of deionized water
Dissolved at 0 ° C. The gelatin solution was then added to 11.7.
1 of silver halide equivalent to millimoles of silver halide
19.35 g of the 1.44 wt% dispersion was added over 20 seconds with stirring. Next, a 0.05% by weight solution of aminoiminomethanesulfinic acid (RS02) was added in a molar% amount based on the silver halide shown in Table 1, and the silver halide was heated at 40 ° C. for 30 minutes with stirring. Reduction sensitization at the venue. Next, the amount of silver nitrate shown in Table 1 was added as a 3.56% by weight solution, and the resulting dispersion was treated with deionized water while maintaining the temperature at 40 ° C.
Supplemented to 5.4 g. After stirring at 40 ° C. for 1 hour, UA
g (UAg-1), then add 206.6 g of the above silver behenate dispersion together with 2.4 g of 1N nitric acid and stir at 40 ° C. for a further 20 minutes before a second UA
g measurement (UAg-2) was performed.

After the second UAg measurement, the following components were added: 8.7 g of a 4 g / L solution of SENSI 01, followed by stirring for 20 minutes, then STABI in methanol
11.8 g of an 8% by weight solution of C.01, and finally, just prior to coating, 4.68% by weight of phthalazine, 16.
84% by weight of LOWINOX 22IB46 and 2% by weight of surfactant Nr. 112 g of a dispersion containing 2.

[0081]

[Table 1]

Preparation of Photothermographic Recording Material 62.5 g of K7 in 1 L of deionized water at 40 ° C.
By dissolving 598, an antihalation layer dispersion liquid was prepared. Following the resulting gelatin solution, one of a 10% by weight aqueous solution of the following components: ANTIHALO 01
4.5 g, 8 g of a 10% by weight aqueous dispersion of LATEX 01 and 42 g of a 20% by weight aqueous dispersion of KIESELSOL 300F were added, and finally the pH was adjusted to 6, then the primed 100 μm poly on both sides was added. (Ethene terephthalate) One side of the support was coated to a wet-layer thickness of 45 μm and dried at 25 ° C. for 5 minutes.

Next, 49.2 g of 1928.2 g of deionized water were added.
At 0 ° C. dissolve 42.5 g of K7598 and then, with stirring, the following ingredients: 8.7 g of STABI 0
2, 179.1 g of STABI 03-dispersion (17.
5% by weight STABI 03, 10% by weight K7598
And 1% by weight of surfactant Nr. 227.
6 g of 1-phenyl- dissolved in 3 g of methanol
5-mercapto-tetrazole and surfactant Nr.
A solution for the first layer of the thermosensitive element was prepared by adding 17.4 g of a 3% 10% solution.

The solution for the first layer of the thermosensitive element is then coated on the side of the support which has not been coated with an antihalation layer to a wet layer thickness of 50 μm,
After drying at 5 ° C. for 5 minutes, a first layer of the thermosensitive element was formed.

The first layer of the thermosensitive element was then overcoated with the aqueous dispersion described above to a wet layer thickness of 100 μm and dried at 25 ° C. for 5 minutes to form a second layer of the thermosensitive element.

Finally, the second layer of the heat-sensitive element contains the surfactant Nr. 78 g of a 5% by weight solution of 4 are added
A solution of 57 g of K7598 in 560 g of deionized water was overcoated to a wet layer thickness of 50 μm and dried at 25 ° C. for 5 minutes before forming a protective layer.

Evaluation of Photothermographic Recording Materials The photothermographic recording materials of Examples 1 to 6 of the present invention and Comparative Examples 1 and 2 were first loaded with He through a grayscale wedge to change film exposure.
-Ne laser (632.8 nm) and then 1
Heating at 00 ° C. for 20 seconds formed a wedge image. The print density variation in the wedge image was determined using a MACBETHTD 903 densitometer with a visible filter to obtain the dependence of optical density on exposure. Dm
The S-value, defined as the exposure in mJ / m ² at which an optical density of 1.0 above in was achieved, was determined from these optical density-exposure dependencies. The lower the exposure value, S, required to obtain an optical density 1.0 higher than Dmin, the higher the photosensitivity of the photothermographic material.

Photothermographic recording materials stabilized by subjecting to 7 days at 45 ° C. and 70% relative humidity were subjected to photothermographic evaluation to determine background density Dmin and S-value. The results of this evaluation of the photothermographic recording materials of Examples 1-6 of the present invention and Comparative Examples 1 and 2 are summarized in Table 2 below.

[0089]

[Table 2]

The photothermographic printing performance of the photothermographic recording materials of Examples 1 to 3 of the present invention and Comparative Example 1 was evaluated by the reduction using aminoiminomethanesulfinic acid (RS02) in the absence of a water-soluble silver salt. Resulted in significantly lower S-values, i.e., significantly higher sensitivities. The best performance was achieved with 1.57 mmol of RS02 per mole of silver halide (Inventive Example 2).

The photothermographic printing performance of the photothermographic recording materials of Examples 4 to 6 of the present invention and Comparative Example 2 was evaluated by the reduction using aminoiminomethanesulfinic acid (RS02) in the presence of a water-soluble silver salt. Showed significantly lower S-values, ie, significantly higher sensitivities, and also a significant decrease in Dmin from 0.37 to 0.31.

The benefits arising from both the addition of the water-soluble silver salt and the reduction with aminoiminomethanesulfinic acid in the reduction in Dmin value achieved can be seen, and the observed S-value is comparable to that of the water-soluble silver. It was equivalent to under no added salt.

Examples 7-14 of the Invention The photothermographic recording materials of Examples 7-14 of the invention were prepared using tin (II) bromide instead of a 0.5% by weight solution of RS02 (aminoiminomethanesulfinic acid). (RS0
Prepared as described for Examples 1-6 of the present invention and Comparative Examples 1 and 2, except that a 0.1% by weight solution of 1) was added. The manufacturing conditions for the photothermographic recording materials of Examples 7-14 of the present invention, together with those for Comparative Examples 1 and 2, are summarized in Table 3 below.

[0094]

[Table 3]

Photothermographic evaluations of the photothermographic recording materials of Examples 7-14 of the present invention were performed as described for the photothermographic recording materials of Examples 1-2 of the present invention and Comparative Examples 1 and 2. The results obtained are summarized in Table 4 below together with the results for the photothermographic recording materials of Comparative Examples 1 and 2.

[0096]

[Table 4]

Examples 7 to 11 of the present invention and Comparative Example 1
The photothermographic printing performance of the photothermographic recording material of Example 1 shows that the reduction with tin (II) bromide (RS01) is significantly lower with no water-soluble silver salt added.
-Value, ie, a significantly higher light sensitivity. Best performance is 0.46 per mole of silver halide
Achieved using millimolar RS01 (Example 8 of the present invention).

The photothermographic printing performance of the photothermographic recording materials of Examples 12 to 14 of the present invention and Comparative Example 2 was evaluated using tin (II) bromide (RS01) under the addition of a water-soluble silver salt. S with significantly lower reduction
-Value, i.e. significantly higher sensitivity, and also slightly lower than the Dmin obtained using the photothermographic recording material of Comparative Example 2 (Example 1 of the present invention).
2) to Dmin values slightly higher than those obtained with the photothermographic recording material of Comparative Example 2 (Examples 13 and 14 of the present invention).

Addition of a water-soluble silver salt and tin (II) bromide (R
The benefits resulting from using both reduction with S01) are seen in a further decrease in S-value, ie a further increase in light sensitivity.

Examples 15 to 18 of the Invention The photothermographic recording materials of Examples 15 to 18 of the invention were prepared in the same manner as in Table 2 except that various reducing agents were added in place of tin (II) bromide. Manufactured as described for Inventive Examples 1-6 and Comparative Examples 1 and 2.
The manufacturing conditions for the photothermographic recording materials of Examples 15-18 of the present invention, together with those for Comparative Examples 1 and 2, are summarized in Table 5 below.

[0101]

[Table 5]

Photothermographic evaluations of the photothermographic recording materials of Examples 15-18 of the present invention were performed as described for the photothermographic recording materials of Examples 1-2 of the present invention and Comparative Examples 1 and 2.
The results obtained are summarized in Table 6 below together with the results for the photothermographic recording materials of Comparative Examples 1 and 2.

[0103]

[Table 6]

The photothermographic printing performances of the photothermographic recording materials of Example 15 of the present invention and Comparative Example 1 were measured with NaH ₂ P without adding a water-soluble silver salt.
S- with significantly lower reduction using O ₂ (RS17)
Values, i.e. significantly higher sensitivities.

The photothermographic printing performances of the photothermographic recording materials of Examples 16 to 18 of the present invention and Comparative Example 2 were determined by adding potassium sulfite (RS06), Na ₂ HPO ₃ ( RS13) and NaH ₂ PO ₂ (RS17) significantly lower the reduction with S- value, i.e. showed that produces high photosensitivity significantly.

Comparative Examples 3 to 15 The photothermographic recording materials of Comparative Examples 3 to 15 were added in place of tin (II) bromide with various reducing agents outside the scope of the present invention in the amounts shown in Table 7. Except for Example 1 of the present invention
-6 and Comparative Examples 1 and 2. The production conditions for the photothermographic recording materials of Comparative Examples 3 to 15 together with those for Comparative Examples 1 and 2 are summarized in Table 7 below.

[0107]

[Table 7]

The photothermographic evaluations of the photothermographic recording materials of Comparative Examples 3 to 15 were performed as described for the photothermographic recording materials of Examples 1 to 2 of the present invention and Comparative Examples 1 and 2. The results obtained are summarized in Table 8 below together with the results for the photothermographic recording materials of Comparative Examples 1 and 2.

The photothermographic printing performance of the photothermographic recording materials of Comparative Examples 3 to 11 and Comparative Example 1 was measured under the condition that a water-soluble silver salt was not added and a reducing agent: dimethylaminoborane (R01), iron sulfate ( II) (R0
2), 1-formyl, 2-phenylhydrazine (R0
3) and treatment with ascorbic acid (R04) resulted in significantly higher S-values, i.
It has been shown to occur with a rise in the min value. This is surprising in that these reducing agents have been reported to be effective reduction sensitizers for silver halide in silver halide emulsions.

[0110]

[Table 8]

The photothermographic printing performances of the photothermographic recording materials of Comparative Examples 12 to 15 and Comparative Example 2 were measured by adding a water-soluble silver salt to a reducing agent: iron (II) sulfate (R02), ascorbin. Treatment with acid (R04) and ethanolamine (R05) was shown to result in significantly higher S-values and forbidden higher Dmin values except for ethanolamine (R05). This is surprising in that these reducing agents have been reported to be effective reduction sensitizers for silver halide in silver halide emulsions.

Having described preferred embodiments of the invention in detail, it will now be appreciated that numerous modifications may be made in embodiments without departing from the scope of the invention as defined in the appended claims. It will be apparent to those skilled in the art.

 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Johan Lokiyuye, Belgium Bee 2640 Malt Cell Septes Trat 27 Agfa-Gevert Na Mrose Fennoutjap (72) Inventor Ivan Gilliams Belgium Bee 2640 Malt Cell・ Septes Trat 27 ・ Aghua-Gevuert ・ Na Mrose ・ Fennout shop F term (reference) 2H123 AB00 AB03 AB23 AB25 BB00 BB24 CB00 CB03

Claims (4)

[Claims] 1. An aqueous emulsion comprising a binder or surfactant, a substantially non-photosensitive and substantially water-insoluble organic silver salt and a photosensitive silver halide, wherein the aqueous emulsion further comprises tin (II) bromide. ,
Comprise a sensitizer selected from the group consisting of salt ^- aminoiminomethanesulfinic acid, water-soluble salts of H ₃ PO _3, water-soluble salts of H ₃ PO _2, water-soluble SO ₃ ^2-salt and water-soluble HSO ₃ An aqueous dispersion characterized by the following. 2. (i) preparing a dispersion of photosensitive silver halide in an aqueous medium; (ii) adding tin bromide (I) to the dispersion prepared in step (i).
I), aminoiminomethanesulfinic acid, H ₃ water-soluble salts of PO _3, H ₃ PO ₂ in water-soluble salts, water-soluble SO ₃ ^2-salt and water-soluble HSO ₃ ^- at least one selected from the group consisting of salt (Iii) adding a substantially non-photosensitive and substantially water-insoluble organic silver salt. 3. A photo-addressable heat-developable element comprising a support and a photo-addressable heat-developable element, the photo-addressable heat-developable element comprising two requirements: (i) the photo-addressable heat-developable element is substantially A non-photosensitive and substantially water-insoluble organic silver salt; a reducing agent in thermal working relationship therewith for a substantially non-photosensitive and substantially water-insoluble organic silver salt; And (ii) the photo-addressable heat developable element comprises a layer obtainable by coating an aqueous dispersion according to claim 1 on the support. Fill photothermographic recording material. 4. A substantially non-photosensitive and substantially water-insoluble organic silver salt, a reducing agent and a bond for said substantially non-photosensitive and substantially water-insoluble organic silver salt light containing the agent - for improving the sensitivity of the photothermographic recording materials with photo-addressable thermally developable element, tin bromide (II), aminoiminomethanesulfinic acid, H ₃ P
Use of a sensitizing agent selected from the group consisting of salt ^- water-soluble salts of O _3, H ₃ water-soluble salts of PO _2, water-soluble SO ₃ ^2-salt and water-soluble HSO _3.