DE69733601T2 - Photothermographic recording material that can be coated from an aqueous medium - Google Patents

Description

technical Field of the invention

The The present invention relates to a photothermographic recording material. the one from watery Containable media photoaddressable, heat-developable element.

general State of the art

at thermal imaging or thermography is concerned to a recording method in which images by means of heat energy be generated. In direct thermal imaging is a visible image pattern produced by image-wise heating a recording material, containing substances, their color or optical density is due to chemical or physical Operations changes. Such thermographic materials can be made photothermographically by a radiation-sensitive Embedded after exposure to ultraviolet radiation, visible light or infrared light is capable of thermographic Effect, by the changes the color or the optical density can be caused to catalyze or assist.

Examples for photothermographic Materials are the so-called "dry silver" photographic materials of the 3M Company, of which an overview by D. A. Morgan in "Handbook of Imaging Science ", edited by A.R. Diamond, page 43, published by Marcel Dekker, 1991, is given.

In US-P 3,152,904 discloses an image reproduction sheet comprising a radiation-sensitive heavy metal salt, which by a substantial even lateral Irradiation of the arc with a radiation wavelength between the wavelength of X-rays and a wavelength can be reduced from 5 microns to a free metal, and as image-forming component contains an oxidizing-reducing reaction combination, the Although under ambient conditions is substantially latent, but under Exposure of the free metal react and thereby a visible change color, an organic silver salt with carbon atoms contains differs from the heavy metal salt by its oxidizing effect and further an organic reducing agent having carbon atoms contains wherein the radiation-sensitive heavy metal salt in an amount between about 50 and about 1000 ppm, based on the oxidizing-reducing Reaction combination, contained in the sheet.

JP 54-156527 discloses a heat-developable radiation-sensitive material comprising (a) an organic silver photosensitive salt oxidizer, (b) iodine, (c) a silver ion reducing agent, and (d) an N-containing organic base, optionally an acidic one Contains proton in one molecule and has a pKa of conjugated acid between 0.5 and 10, with pyridine, quinoline, quinazoline, phthalazine, their derivatives, etc. being preferred as (d), for example. Further, U.S. Patent No. 3,994,732 discloses a dry silver photosensitive heat-developable sheet material containing an imaging system comprising an agent capable of forming a photosensitive silver halide catalyst and a thermosensitive image-forming agent comprising an organic silver compound and a reducing agent therefor which accelerates the oxidation-reduction reaction leading to the formation of a visible image by the catalyst and also sufficient toner to increase the density of the visible image, the improvement being that the toner is a mixture of (a) phthalazine and ( b) at least one acid of the formula RAR ₁ in which A is a phenyl or naphthyl group and R and R _{1 are} -COOH- or -CH ₂ COOH groups, where R and R _{1 are} attached to the 2- or 3- Position of A are bound, or an anhydride of the acid RAR is ₁ .

In US-P 4,442,202 is a photothermographic in Example 5 of the invention Material A16 discloses a silver behenate emulsion layer consisting of a silver behenate suspension in toluene and methyl ethyl ketone (weight ratio of this mixture = 1: 2), Polyvinyl butyral, silver iodide and silver bromide and other ingredients and one of a reducing agent, phthalazinone and cellulose acetate butyrate-containing solution over it. Of the Molar percentage of silver iodide to silver halide in the silver behenate emulsion layer is 80.4 mol%.

in der R die zum Vervollständigen eines fünfgliedrigen heterocyclischen Ringes benötigten Atome und Z eine Alkylengruppe mit 1 bis 30 Kohlenstoffatomen bedeutet, (2) eine ein Reduktionsmittel enthaltende Reduktionsmittellösung, (3) ein Bindemittel und (4) eine strahlungsempfindliche, einen spektralen Sensibilisierungsfarbstoff enthaltende Silberhalogenidzusammensetzung.US-P 4,105,451 discloses a process for producing a photothermographic composition, wherein the following ingredients are added sequentially: (1) a dispersion containing a 2-mercaptobenthiazole, 2-mercaptobenzimidazole, 2-mercaptobenzoxazole or Mercaptobenzoselenazole compound and a silver salt of a heterocyclic thion of the formula

wherein R is the atom necessary to complete a five-membered heterocyclic ring and Z is an alkylene group having 1 to 30 carbon atoms, (2) a reducing agent-containing reducing agent solution, (3) a binder, and (4) a radiation-sensitive spectral sensitizing dye-containing silver halide composition.

in der R die zum Vervollständigen eines fünfgliedrigen heterocyclischen Ringes benötigten Atome und Z eine Alkylengruppe mit 1 bis 30 Kohlenstoffatomen bedeutet, und (ii) einem organischen Reduktionsmittel, und (c) einem Toner, wobei die Verbesserung darin besteht, das der Toner eine heterocyclische Mercaptoverbindung aus der Gruppe bestehend aus 3-Mercapto-1H-1,2,4-triazol-, 3-Imin-5-thiourazol-, 4-Methyl-3,5-dithiourazol-, 4-Phenyl-3,5-dithiourazol-, 4-(p-Methoxyphenyl)-3,5-dithiourazol-, 2,4-Dimercaptopyrimidin-, 8-Mercaptopurin- und 2,6-Dimercaptopurin-Tonern enthält.U.S. Patent No. 4,201,582 discloses a photothermographic element comprising a support and cast thereon (a) photographic silver halide in relation to (b) an image-forming combination of (i) a silver salt of a heterocyclic thione of the formula

wherein R is the atom needed to complete a five-membered heterocyclic ring and Z is an alkylene group having from 1 to 30 carbon atoms, and (ii) an organic reducing agent, and (c) a toner, the improvement being that the toner is a heterocyclic mercapto compound from the group consisting of 3-mercapto-1H-1,2,4-triazole, 3-imine-5-thiourazole, 4-methyl-3,5-dithiourazole, 4-phenyl-3,5-dithiourazole , 4- (p-methoxyphenyl) -3,5-dithiourazole, 2,4-dimercaptopyrimidine, 8-mercaptopurine and 2,6-dimercaptopurine toners.

In US-P 4,743,534 discloses a radiation-sensitive material, consisting essentially of radiation-sensitive silver halide grains and one the grains inclusive dry binder resin, wherein the binder resin of the radiation sensitive Material solved can be, so that the radiation-sensitive material directly a light insensitive reducible metal compound and a reducing agent for it containing photothermographic system can be added wherein the silver halide grains by a process, in the ionizable silver salt and ionizable halide in one of the binder resin and an inert one organic solvent containing solution to form first silver halide nuclei, and subsequently in at least one incremental addition at such a rate an additional Amount of ionizable silver salt and ionizable halide in the solvent be entered that extra Do not make silver halide germs any faster than those first formed Silver nuclei.

in der R¹ eine Alkylgruppe, Aralkylgruppe, Cycloalkylgruppe oder Alkenylgruppe mit bis zu 26 Kohlenstoffatomen oder eine Arylgruppe mit bis zu 14 Kohlenstoffatomen ist und R² ein Wasserstoffatom, eine Alkylgruppe, eine am 1,2-Diazinring anellierte Cycloalkylgruppe oder die zum Vervollständigen eines 5- oder 6-gliedrigen aromatischen, am 1,2-Diazinring anellierten Ringes darstellt, (c) ein Reduktionsmittel für die strahlungsunempfindliche reduzierbare Silberquelle und (d) ein Bindemittel enthält.U.S. Patent No. 5,350,669 discloses a photothermographic element comprising a support coated with at least one heat-developable radiation-sensitive, photothermographic emulsion layer comprising (a) a radiation-sensitive silver halide, (b) a radiation-insensitive, reducible silver source containing a silver carboxylate / 1 , 2-diazine coordination compound of the formula

wherein R ^{1 is} an alkyl group, aralkyl group, cycloalkyl group or alkenyl group having up to 26 carbon atoms or an aryl group having up to 14 carbon atoms, and R ^{2 is} a hydrogen atom, an alkyl group, a cycloalkyl group fused to the 1,2-diazine ring, or to complete a 5 or 6-membered aromatic ring fused to the 1,2-diazine ring, (c) a reducing agent for the radiation-insensitive reducible silver source and (d) a binder.

In U.S. 4,585,734 there is disclosed a photosensitive, heat-developable dry silver based sheet material containing an imaging system comprising a preformed silver halide radiation-sensitive compound-forming compound and a reducing agent therefor for accelerating the oxidation-reduction reaction by the catalyst to form a visible image; and further sufficient toner to increase the density of the visible image, the improvement being that the toner is a mixture of (a) phthalazine and (b) at least one active hydrogen-containing heterocyclic compound having a 5, 6 or 7 is a heterocyclic ring having only C, N, S, O and Se ring atoms.

at photothermographic materials that are based on a substantially light-insensitive organic silver salt, radiation-sensitive silver halide in intimate catalytic relationship to the organic silver salt and a reducing agent for Based on the organic silver salt, the standard doctrine is that the organic silver salt optionally in the presence of ex situ formed silver halide in an aqueous medium and formed subsequently like and dried, before in an organic solvent-containing medium, from after which the dispersion is applied to be dispersed. For photothermographic materials, the silver halide becomes either prepared ex situ and a dispersion of the organic silver salt added as described in US-P 3,080,254, it is already during the Formation of the organic silver salt, as described in US Pat. No. 3,839,049, or in situ by reaction with a Halide ion source formed from the organic silver salt, such as in US Pat. No. 3,457,075. In situ formation involves the reaction of organic silver salt with an inorganic or organic Halide ion source after dispersing the organic silver salt in a solvent-containing Medium instead of, i. in a non-aqueous medium.

This Preparation process is very inappropriate because the organic silver salt separated after its formation in water and then dried must be, before in a solvent-containing In addition, to be dispersed in a medium is polluting to the environment, since the evaporation of the solvent while takes place during the coating process, and is during the Preparation of the organic silver salt dispersion and the coating a time-consuming process with high factory costs, because provision to prevent of solvent explosion are indispensable and the solvent recovered must be to emission of the solvent to avoid the environment.

Farther is it desirable in spectral terms to sensitize the radiation-sensitive silver halide in aqueous media and because this is the range of usable spectral sensitizing dyes is extended.

In WO-A 97/48014, WO-A 97/48015, WO-A 97/04355, WO-A 97/04356 and WO-A Although 97/04357 (PCT / EP / 02579 to PCT / EP / 02583) is attempted this Lack remedies, but the materials show after their processing an unsatisfactory resistance on.

Tasks of present invention

A The first object of the present invention is to provide a photothermographic Recording material with a photo-addressable, heat-developable To provide element with excellent image-forming properties.

A Second object of the present invention is to provide a photothermographic Recording material with a photo-addressable, heat-developable Element based on a substantially light-insensitive silver salt a fatty acid, radiation-sensitive silver halide in catalytic relationship to the silver salt of a fatty acid and an organic reducing agent for the silver salt of a fatty acid no intermediate step for drying the silver salt of an organic carboxylic acid is required.

A Another object of the present invention is to provide a photothermographic Recording material with a photo-addressable, heat-developable Element based on a substantially light-insensitive silver salt a fatty acid, radiation-sensitive silver halide in catalytic relation to the Silver salt of a fatty acid and to provide an organic reducing agent for the silver salt of a fatty acid, wherein the element consists of an aqueous Medium can be applied.

A Another object of the present invention is to provide a photothermographic Recording material with improved resistance after its processing provide.

Further Objects and advantages of the present invention will become apparent from the the following description.

Short illustration of the present invention

Be solved the tasks of the invention by a process for producing a photothermographic recording material with a carrier and a photo-addressable heat-developable element, the radiation-sensitive silver halide in catalytic relationship to a substantially light-insensitive silver salt of a fatty acid organic reducing agent for the substantially light-insensitive silver salt of a fatty acid in thermal effective relationship thereto, a surfactant and a water-soluble binder, a water-dispersible binder or a mixture of a water-soluble Binder and a water-dispersible binder, wherein the process comprises the steps of: (1) preparing an aqueous Dispersion or of aqueous Dispersions, the radiation-sensitive silver halide, a substantial light-insensitive silver salt of a fatty acid, an organic reducing agent for the essentially light-insensitive silver salt of a fatty acid and a water-soluble A binder, a water-dispersible binder or a mixture from a water-soluble Binder and a water-dispersible binder contains or contain, (ii) application of the aqueous Dispersion (s) on a support to form a photo-addressable heat-developable element on the carrier, characterized in that at least 80 mol% of the radiation sensitive Silver halide is silver iodide and the aqueous (s) dispersion (s) further contains a diazine compound or included.

Be solved the tasks of the invention also by a photothermographic recording material with a carrier and a photo-addressable heat-developable one Element, the radiation-sensitive silver halide in catalytic Relationship to a substantially light-insensitive silver salt of a Fatty acid, an organic reducing agent for the substantially light-insensitive Silver salt of a fatty acid in a thermally effective relationship thereto and a water-soluble one A binder, a water-dispersible binder or a mixture from a water-soluble Binder and a water-dispersible binder contains, characterized characterized in that at least 80 mol% of the radiation-sensitive Silver halide is silver iodide and the photoaddressable heat developable Element further a surfactant and an optionally substituted Contains phthalazine compound.

preferred embodiments The present invention is described in the detailed description of the present Invention disclosed.

Full Description of the present invention

Aqueous

Under The term "watery" in the sense of the present invention mixtures of water and water-miscible organic solvents such as alcohols, e.g. Methanol, ethanol, 2-propanol, butanol, isoamyl alcohol, Octanol, cetyl alcohol, etc., glycols, e.g. Ethylene glycol, glycerin, N-methylpyrrolidone, methoxypropanol, and ketones, e.g. 2-propanone and 2-butanone, etc., to be understood.

diazine

Under the term "diazine compound" is understood in Meaning of the present invention i.a. heterocyclic ring systems with at least two azine groups, in the same or different may be present with each other fused heterocyclic rings, and substituted diazine compounds and fused diazine compounds, which can be substituted themselves. Suitable substitution groups are, for example, an alkyl, a substituted alkyl, hydroxyl, alkoxy, carboxyl and carboxylester groups.

The diazine compound may also be in the form of a complex, such as the silver carboxylate described in U.S. Pat. No. 5,350,669, as a metal salt, as an amine complex or as a complex with inorganic salts. The diazine compound may be contained in the same layer of the photo-addressable thermally-developable element as the silver salt of an organic carboxylic acid or in another layer in thermally effective relationship thereto. It may also be incorporated as a dispersion in a dispersion medium which substantially prevents its diffusion during the manufacture and storage of the photothermographic material of the present invention while the evolution of heat permits its diffusion and thereby its participation in the heat development process. After a preferred Embodiment of the present invention, the diazine compound is a 1,2-diazine compound or substituted 1,2-diazine compound, and in a particularly preferred embodiment, the diazine compound is phthalazine or substituted phthalazine.

suitable Diazine compounds according to the invention are phthalazine, pyridazine, cinnoline, benzo (c) cinnoline, naphthyridine, Pyrimidine, pyrazine, quinazoline, quinoxaline, purine and substituted Derivatives thereof. examples for preferred substituted diazine compounds are: 1 (2H) -phthalazinone, substituted 1 (2H) -phthalazinones, 2,3-dihydro-1,4-phthalazinedione, substituted 2,3-dihydro-1,4-phthalazinediones and the same.

Water dispersible and water-soluble binder

The Photoaddressable according to the invention developable Contains element as a binder, a water-soluble A binder, a water-dispersible binder or a mixture from a water-soluble Binder and a water-dispersible binder. In a preferred embodiment In the present invention, the binder is a polymeric latex.

When water-dispersible binder are all water-insoluble Polymers, e.g. water Cellulose derivatives, Polymers derived from α, β-ethylenic unsaturated Compounds such as polyvinyl chloride, post-chlorinated polyvinyl chloride, Copolymers of vinyl chloride and vinylidene chloride, copolymers of Vinyl chloride and vinyl acetate, polyvinyl acetate and partially hydrolyzed Polyvinyl acetate, polyvinyl alcohol, polyvinyl acetals made from polyvinyl alcohol as starting material, in which only a part of the repeating vinyl alcohol units optionally reacted with an aldehyde are prepared, preferably polyvinyl butyral, copolymers of acrylonitrile and acrylamide, polyacrylate, polymethacrylate, Polystyrene and polyethylene or mixtures thereof. It should be noticed be that there is no clear transition with tiny polymer particles between a polymer dispersion and a polymer solution, whereby the smallest particles of the polymer in dissolved form and the slightly larger particles will be in dispersed form.

suitable water-soluble inventive polymers are gelatin, gelatin derivatives, polyvinyl alcohol, polyacrylamide, polyacrylic acid, polymethacrylic Polyethylene glycol, polysaccharides such as starch, gum arabic and dextran, and water-soluble Cellulose derivatives.

to Improvement of the coating-forming properties of water-soluble and water-dispersible polymers can be plasticizers in the polymers embedded, water-miscible solvents added to the dispersion medium and mixtures of water-soluble Polymers, mixtures of water-dispersible polymers or mixtures from water-soluble Polymers and water-dispersible polymers.

photo-addressable developable element

The Photoaddressable according to the invention developable Contains element radiation-sensitive silver halide in catalytic relationship to a substantially light-insensitive silver salt of a fatty acid organic reducing agent for the substantially light-insensitive silver salt of a fatty acid in thermal effective relationship thereto and a water-soluble binder, a water-dispersible Binder or a mixture of a water-soluble binder and a water-dispersible binder, characterized in that at least 80 mol% of the radiation-sensitive silver halide Silver iodide and the photo-addressable thermally developable element are further contains a diazine compound. The element may contain a layered structure in which the silver halide in catalytic relation to the substantially light-insensitive silver salt a fatty acid, the spectral sensitizer, optionally in combination with a Supersensitizer, in sensitizing relation to the silver halide particles and the other ingredients used in the heat development process or effective in pre- or post-development stabilization of the element are, in the same layer or in different layers are included, with the proviso that the organic reducing agent and the possible toning agent in thermal effective relation to the substantially light insensitive Silver salt of a fatty acid stand, i. while the heat development process the reducing agent is capable of being substantially light insensitive To diffuse silver salt of a fatty acid.

Light-insensitive silver salt a fatty acid

The aliphatic carbon chain of the fatty acid, the light-insensitive silver salt of a fatty acid preferably contains at least 12 carbon atoms, for example silver laurate, silver palmitate, silver stearate, silver hydroxystearate, silver oleate and silver behenate, these silver salts are also referred to as "silver soaps".

Of the Term substantially light-insensitive silver salt of a fatty acid in the context of the present invention also mixtures of silver salts of fatty acids.

Production of particles of silver salts of fatty acids

particle the silver salts of fatty acids are by reaction of a soluble Silver salt with the fatty acid or a salt formed therefrom.

To a process for producing a photothermographic according to the invention Contains recording material or contain the aqueous (s) Dispersion (s) an aqueous Suspension of particles of a substantially light-insensitive silver salt a fatty acid, by simultaneous dosing of an aqueous solution or suspension of a fatty acid or its salt formed therefrom and an aqueous solution of a silver salt in an aqueous one liquid wherein the metered addition of the aqueous solution or suspension of the fatty acid or their silver salt formed therefrom and / or the aqueous solution of the silver salt by the silver ion ratio or anion ratio of the Silver salt in the aqueous liquid is controlled.

Be solved the tasks of the invention also by a process for producing a photothermographic A recording material further characterized by the step is, in the particle of the radiation-sensitive silver iodide a silver ion excess the particles of the substantially light-insensitive silver salt of a fatty acid getting produced.

A radiation-sensitive silver

The used according to the invention radiation-sensitive silver halide can be in a ratio between 0.1 and 35 mol%, based on the substantially light-insensitive Silver salt of a fatty acid, be used, preferably in a ratio between 0.5 and 20 mol% and more preferably in a ratio between 1 and 12 mol%. In a preferred according to the invention embodiment is at least 90 mol% of the radiation-sensitive silver halide Silver iodide. The silver iodide may be sensitive to any radiation Shape, such as u.a. in an α, β and γ phase become.

The used according to the invention Although silver halide can be used without modification, but can also with a chemical sensitizer such as a compound that Sulfur, selenium, tellurium, etc., or a compound, the gold, platinum, palladium, iron, ruthenium, rhodium, iridium, etc. contains a reducing agent such as tin halide, etc., or a combination the same are chemically sensitized. More details about this Methods are described by T.H. James in "The Theory of the Photographic Process", 4th Edition, Macmillan Publishing Co. Inc., New York (1977), Chapter 5, pages 149 to 169, described.

Emulsion of the silver salt a fatty acid and the radiation-sensitive silver halide

The Silver halide may be photoaddressable in any manner thermosensitive Element be added, provided, however, that it is in catalytic proximity embedded to the substantially light-insensitive silver salt of a fatty acid becomes. The silver halide and the substantially light-insensitive Silver salt of a fatty acid, the separate, i. ex situ or "preformed", made in a binder, can however, may be mixed prior to their use to make a casting solution also in an appropriate manner long time before being used. Is appropriate also the application of a method in which at least an iodine-containing compound, optionally in combination with an iodine-free halogen-containing compound added to the silver salt of a fatty acid is used to form the substantially light-insensitive silver salt of a fatty acid Part to convert silver halide, as described in US-P 3,457,075.

To a preferred according to the invention embodiment are the particles of the radiation-sensitive silver halide in photo-addressable heat-developable Element evenly over and between particles of the substantially light-insensitive silver salt a fatty acid distributed and has at least 80% by number of the particles of the radiation-sensitive Silberhalogenids a through an electron micrograph determined diameter of at most 40 m up.

In a further embodiment of the invention includes to the preparation of the suspension of particles of a material light-insensitive silver salt immediately in-situ production of silver halide in the same vessel, one being radiation sensitive Suspension is produced.

The aqueous emulsion of the silver salt of a fatty acid optionally containing radiation-sensitive silver halide can also be formed according to the invention from particles of the silver salt of a fatty acid containing optionally radiation-sensitive silver halide by dispersing the particles in water in the presence of nonionic or anionic surfactants or a mixture of nonionic and anionic surfactants, including any, known to those skilled dispersion technique is used, such as milling in a ball mill, dispersion in an impact mill (rotor-stator mixer), in a Microfluidizer ^®, etc. It may also be a combination of dispersion techniques, for example a first technique for forming a predispersion and a second technique for producing a fine dispersion.

Means of transformation of silver behenate in silver halide

According to the invention, radiation-sensitive Silver halide particles by reaction of an aqueous dispersion of particles the substantially light-insensitive silver salt of a fatty acid with at least one halide conversion agent. suitable Halide conversion agents are water-soluble inorganic halides, such as potassium iodide (KI), organic compounds with ionizable Halogen atoms, such as 2-iodopropionic acid (IPA), and onium salts with halide or polyhalide anions. As inventively preferred Onium salts are organophosphonium, organosulfonium and organo-nitrogen onium cations wherein heterocyclic nitrogen-onium (e.g., pyridinium), quaternary Phosphonium cations and ternary Sulfonium cations are preferred. Inventive onium cations can be polymeric or non-polymeric. Preferred non-polymeric onium salts for one Partial conversion of particles of substantially light insensitive Silver salt of a fatty acid in radiation sensitive according to the invention Silver halide are nitrogenonium polyhalides (NC), for example Tetrabutylammonium iodide (NC08), quaternary phosphonium polyhalides (PC), for example 3- (triphenylphosphonium) -propionic acid bromide (PC02), 3- (triphenylphosphonium) -propionic acid iodide (PCO3) and methyltriphenylphosphonium iodide (PC09) and ternary Sulfonium polyhalides (SC), for example trimethylsulfonium iodide (SC01).

The Onium salts are present in an amount between 0.1 and 35 mol%, preferably between 0.5 and 20 mol% and more preferably between 1 and 12 mol%, based on the amount of substantially light-insensitive Silver salt of a fatty acid, used.

The halide conversion agent according to the invention can in solid or dissolved Form added or by metathesis between a salt with Halide or polyhalide anions and onium salts with others Anions as the halide or polyhalide anions in the aqueous Dispersion of particles of the substantially light-insensitive silver salt be formed.

organic reducing agent

suitable organic reducing agents for the reduction of the essentially light-insensitive silver salt of a fatty acid are organic compounds that have at least one active, O, N or C bound hydrogen atom. Particularly suitable organic reducing agents for the reduction of the essentially light-insensitive silver salt of a fatty acid are non-sulfo-substituted 6-membered aromatic or heteroaromatic Ring compounds having at least three substituents, one of which first a hydroxyl group on a first carbon atom and a second hydroxyl group substituted on a second carbon atom or amino group, with three or five ring atoms in one system of conjugated double bonds from the first carbon atom in the Are removed, wherein (i) the third substituent is part of a fused carbocyclic or heterocyclic ring system (ii) the third substituent or another substituent is none Aryl group or oxoaryl group whose aryl group is replaced by a hydroxyl, Thiol or amino group is substituted, and (iii) the third substituent or another substituent is a non-sulfoelectron-attracting group, when the second substituent is an amino group. Particularly preferred reducing agents are substituted pyrocatechols or substituted hydroquinones, whereby 3- (3 ', 4'-dihydroxyphenyl) propionic acid, 3', 4'-dihydroxybutyrophenone, Methyl gallate, ethyl gallate and 1,5-dihydroxynaphthalene in particular to be favoured.

During the development of heat, the reducing agent must be present in such a way that it diffuses into the particles of the essentially light-insensitive silver salt of a fatty acid and thus that Reduction of the substantially light-insensitive silver salt of a fatty acid can take place.

Auxiliary reducing agents

The abovementioned reducing agents which are used as primary or main reducing agents can be considered be used in conjunction with so-called auxiliary reducing agents. As an auxiliary reducing agent, in conjunction with the above Main reducing agents are usable, are organic reducing metal salts, e.g. Tin distearate as described in U.S. Patent Nos. 3,460,946 and 3,547,648, to call.

spectral sensitizer

To a preferred according to the invention embodiment contains the photoaddressable heat developable Element of the photothermographic material further comprises Dye with a maximum absorbency between 600 and 1,100 nm.

The Photo-addressable heat-developable Element of the photothermographic recording material according to the invention may, optionally in conjunction with a supersensitizer, a spectral sensitizer for contain the silver halide. The silver halide can with different known dyes such as cyanine dyes, merocyanine dyes, Styryl dyes, hemicyanine dyes, oxonol dyes, hemioxonol dyes and xanthene dyes, if appropriate, especially when sensitized for infrared radiation, in the presence of a so-called supersensitizer, spectrally sensitized become. Cyanine and merocyanine dyes with imino groups or carboxyl groups are particularly useful. When suitable infrared sensitizers for silver halide are the in EP-A 465 078, 559 101, 616 014 and 635 756, JN 03-080251, 03-163440, 05-019432, 05-072662 and 06-003763 and U.S. Patent Nos. 4,515,888, 4,639,414, 4,713,316, 5,258,282 and 5,441,866. suitable Supersensitizers used in combination with spectral Infrared sensitizers are described in EP-A 559 228 and 587 338 and in US Pat U.S. Patents 3,877,943 and 4,873,184.

thermal solvent

The mentioned above Binders or mixtures thereof may be used in combination with waxes or "thermal Solvents ", also referred to as" thermal solvents ", the the reaction rate of the redox reaction at elevated temperature increase, be used. The term "thermal solvent" is understood in the present invention a non-hydrolyzable organic material that is stable at temperatures below 50 ° C in the solid state in the recording layer, but at Heating to a temperature of more than 60 ° C in the heated area to a Plasticizer for the recording layer becomes and / or acts as a dissolving liquid for at least one of the redox reagents, e.g. the reducing agent for the essential light-insensitive silver salt of a fatty acid, actuated.

tint

To the Obtain a neutral black image tone in the upper density zones and neutral gray in the lower density zones, the photothermographic invention Materials one or more toning agents contain. The toning agents should while the heat processing in thermal effective relation to the substantially light insensitive ones Silver salts and reducing agents are available. It can be any, from the Thermography or photothermography known Tönungsmittel be used.

stabilizers and antifreeze

In order to improve the storage stability and to limit the formation of fog, it is possible to embed stabilizers and antifreezes in the photothermographic materials according to the invention. Examples of suitable stabilizers and antifoggants and their precursors which can be employed singly or in combination include the thiazolium salts described in U.S. Patents 2,131,038 and 2,694,716, the azaindenes described in U.S. Patents 2,886,437 and 2,444,605, the urazoles described in US-P 3,287,135, the sulphopyrocatechols described in US-P 3,235,652, the oximes described in GB-P 623,448, the thiuronium salts described in US-P 3,220,839, which are described in US-P 2 566 263 and 2 597 915, the tetrazolylthio compounds described in US Pat. No. 3,700,457, the mesoionic 1,2,4-triazolium-3-thiolates described in US Pat. Nos. 4,404,390 and 4,351,896 Stabilizer precursors, the tribromomethyl ketone compounds described in EP-A 600 587, the combination of isocyanate compounds and halogenated compounds described in EP-A 600 586, which are described in EP-A 600 589 vinylsulfone and β-halosulfone compounds and those referred to in the context of the invention in Chapter 9 of "Imaging Processes and Materials, Neblette's 8th edition", by D. Kloosterboer, edited by J. Sturge, V. Walworth and A. Shepp, page 279, Van Nostrand (1989), in Research Disclosure 17029, published June, 1978, and in the references described in all of these references.

surfactants

In of the present invention for the preparation of dispersions of particles of the substantially light-insensitive Silver salt of a fatty acid and water-dispersible binders such as polymeric latices in aqueous Media non-ionic, cationic or anionic surfactants used become.

Further ingredients

Except the The above-mentioned ingredients may be the photothermographic recording material contain other ingredients, such as free organic carboxylic acids, antistatic agents, Silicone oil, e.g. BAYSILONE oil A (trade name of BAYER AG, GERMANY), absorbing ultraviolet light Connections, white light reflective and / or ultraviolet radiation reflective pigments, silica and / or optical brightening agents.

antihalation

Except the The above ingredients may photothermographic according to the invention Recording material anti-halation dyes or shade dyes, which absorb the light penetrating the radiation-sensitive layer and thus prevent reflection of this light. Such dyes can be used in the photoaddressable heat developable Element or else in any other, the photothermographic invention Recording material containing layer are incorporated. The antihalation dye may also be either thermally during the heat generation be bleached or light bleached after the heat development as disclosed in U.S. Pat. Nos. 3,984,248, 3,988,154, 3,988,156, 4,111,699 and U.S. Pat 4,359,524. The antihalation dye can also be used in a layer which are removed after exposure can be as described in US-P 4,477,562 and EP-A 491 457. Suitable antihalation dyes for use in combination with infrared light are described in EP-A 377 961 and 652 473, EP-B 101 646 and 102 781 and US-P 4 581 325 and 5 380 635.

carrier

Of the carrier for the Inventive photothermographic Recording material may be translucent, translucent or opaque and is preferably a thinner one flexible carrier from e.g. Paper or polyethylene-coated paper or a film transparent resin, e.g. from a cellulose ester, polypropylene, Polystyrene, polymethacrylate, Polycarbonate or polyester, e.g. Polyethylene terephthalate or polyethylene naphthalate. The carrier may be in the form of a bow, ribbon or web and if necessary subbed with an adhesive layer to ensure adhesion to the heat-sensitive material applied to it To improve the recording layer.

suitable Adhesive layers for improving the adhesion of the photo-addressable heat-developable invention Elements and the antistatic outer backing layer according to the invention on polyethylene terephthalate supports are e.g. in GB-P 1 234 755, US-P 3 397 988, US-P 3 649,336 and US-P 4,123,278, in US-P 4,478,907 and in the "Product Licensing Index ", July 1967, p. 6 Research Disclosure. Suitable pretreatments for hydrophobic resin carriers are for example, a corona discharge treatment and / or an attack treatment with one or more solvents, whereby a microrough surface texture is obtained.

protective layer

To a preferred embodiment of the photothermographic invention The recording material is the photo-addressable heat-developable one Element provided with a protective layer, by the local Deformation of the photoaddressable thermally developable element avoided, improved its abrasion resistance and direct contact with components of the heat development device is prevented.

The protective layer preferably contains a binder which is soluble in solvents (hydrophobic), dispersible in solvents, water-soluble (hydrophilic) or water-dispersible. Particularly preferred hydrophobic binders are polycarbonates, as described in EP-A 614,769. Suitable hydrophilic binders are, for example, gelatin, polyvinyl alcohol, cellulose derivatives or other polysaccharides, hydroxyethyl cellulose, hydroxypropyl cellulose, etc., with curable binders being preferred.

A inventive protective layer can be networked. For the crosslinking includes crosslinking agents such as those described in WO 95/12495 for protective coatings described in question. A protective layer according to the invention may additionally at least a solid lubricant with a melting point below 150 ° C, at least a lubricating fluid in a binder, wherein at least one of the lubricants Phosphoric acid derivative is, and further solved Sliding material included. Furthermore, such protective layer can be particulate material, e.g. optionally from the outer protective layer protruding talc particles, as described in WO 94/11198. It can likewise other ingredients are incorporated into the protective layer, e.g. colloidal particles such as colloidal silica.

Suitable anti-friction coating compositions are described in, for example EP 138 483 . EP 227,090 U.S. Patent Nos. 4,567,113, 4,572,860 and 4,717,711, and in EP-A 311,841, EP-A 492,411 and EP-A 501,072.

Antistatic layer

In a preferred embodiment the recording material according to the invention gets on the outer layer on the non-coated with the photo-addressable heat-developable element Side of the carrier applied an antistatic layer. For this purpose suitable antistatic layers are described in EP-A 444 326, EP-A 534 006 and EP-A 644 456, U.S. Pat. Nos. 5,364,752 and 5,472,832 and DOS 4,125,758.

coating techniques

Of the Application of any layer of the photothermographic materials of the invention can be done by any coating technique, e.g. described in "Modern Coating and Drying Technology ", Edited by Edward D. Cohen and Edgar B. Gutoff, (1992) VCH Publishers Inc. 220 East 23rd Street, Suite 909 New York, NY 10010, USA.

recording method

The Exposure of the photothermographic invention Materials can use radiation with a wavelength between the wavelength of X-rays and a wavelength of 5 microns, with the image either by pixel-wise exposure with a focused light source such as a cathode ray tube, a Ultraviolet laser, a laser for visible light, an infrared laser such as a He / Ne laser, a Infrared laser diode, e.g. emitted at 780 nm, 830 nm or 850 nm, or a light-emitting diode (LED), for example one at 659 nm emitting LED, or by direct exposure of the article itself or an image of the object with a suitable exposure source, such as. an ultraviolet source, visible light or infrared light, is obtained.

For the heat development of imagewise exposed according to the invention Any photothermographic recording material comes heat source in question, within a for the respective application of acceptable period of uniform heating the recording materials to the development temperature ensures e.g. Contact heating, radiant heating, microwave heating etc.

applications

The photothermographic according to the invention Recording materials can for the Generation of both transparencies and supervisory copies be used. For such applications becomes the carrier translucent or opaque, i.e. a white light having reflective aspect. For example, a Paper carrier substrate to be used, the white light may contain reflective pigments, which may also be in an intermediate layer between the recording material and the paper carrier substrate are embedded. When using a translucent support can the carrier colorless or colored, e.g. colored blue, be.

Hardcopy photothermographic recording materials are used on a white opaque support and in medical diagnostics, black-image transparencies are included in a viewing device testing techniques are widely used.

In the photothermographic recording materials of the present invention and comparative examples illustrating the present invention, in addition to the above-mentioned ingredients, the following ingredients are also used: R01: 3- (3 ', 4'-dihydroxyphenyl) propionic acid, R02: 3 ', 4'-Dihydroxybutyrophenon, R03: 1,5-dihydroxynaphthalene, R04: 2- (3 ', 4'-dihydroxyphenyl) acetic acid, R05: 3,4-dihydroxybenzoic acid, R06: Ethyl-2,5-dihydroxybenzoate, LOWINOX ^™ 22IB46: 2-Propylbis (2-hydroxy-3,5-dimethylphenyl) methane from CHEM. WORKS LOWI, the dispersants: ULTRAVON ^TM W: a sodium salt of an alkaryl sulfonate from CIBA-GEIGY, MERSOLAT ^TM H: a sodium salt of an alkylsulfonate from BAYER, and the polymeric binders: Butvar ^™ B79: Poly (vinyl butyral) from MONSANTO, BINDER 01: Copolymer of 45% by weight of methyl methacrylate, 45% by weight of butadiene and 10% by weight of itaconic acid, BINDER 02: NEOCRYL ^™ A550 from POLYVINYL CHEMIE, a 40% by weight dispersion of poly (methyl methacrylate), BINDER 03: METHOCEL ^™ K4M PREMIUM from DOW CORNING, a hydroxyalkyl cellulose.

The the following INVENTION and Explain the comparative examples the present invention. The percentages in these examples are in weight, if nothing else is noted.

COMPARATIVE EXAMPLES 1 and 2

The photothermographic recording materials of the COMPARATIVE EXAMPLES 1 and 2 contain a photoaddressable heat developable Layer resulting from a solvent dispersion is applied to the specificity of the present invention in terms of Photothermographic recording materials, the one from a aqueous Contain dispersion applied photoaddressable heat developable element, to prove.

manufacturing from silver behenate

to Preparation of a silver behenate emulsion becomes a solution of 6.8 kg of behenic acid in 67 l of 2-propanol at 65 ° C poured into a 400 L jar, the subsequently heated In order to maintain the temperature of the contents at 65 ° C, then 96% of the behenic by stirring of 76.8 L of a 0.25 M sodium hydroxide solution in demineralized Water is converted to sodium behenate, eventually becoming 48 l of a 0.4 M silver nitrate solution stirred in demineralised water. After the end of the addition the silver nitrate solution is allowed cool the contents of the vessel and The precipitate is filtered off, washed, slurried with water, again filtered and finally 12 h at 45 ° C dried.

Preparation of a silver behenate dispersion in 2-butanone

281.25 kg of the dried powder containing 4 mol% behenic acid, based on the silver behenate, are then predispersed by conventional dispersion techniques in a solution of 281.25 g of Butvar ^™ B76 in 1,937.5 g of 2-butanone and the resulting Homogenized dispersion in a MICROFLUIDICS ^™ M-110Y high pressure microfluidizer at a jet pressure of 400 bar.

Partial transformation of silver behenate in silver halide

In 4 g of the silver behenate dispersion containing 10.7% by weight of silver behenate, 0.3% by weight of behenic acid and 11% by weight of Butvar ^™ B79 are added 0.72 g of a 5% strength by weight solution of PCO3 stirred in ethanol, wherein PC03 in a ratio of 8 mol%, based on the silver behenate, is contained in the mixture thus obtained.

Coating with a photo-addressable heat-developable layer

To prepare the casting dispersion of COMPARATIVE EXAMPLE 1, 0.16 g of a 5% by weight phthalazine solution in 2-butanone, 0.74 g of a 20% by weight solution of LOWINOX ^™ 22IB46 in 2-butanone, and Finally, 1.2 g of 2-butanone stirred into the PC03-containing silver behenate.

To prepare the casting dispersion of COMPARATIVE EXAMPLE 2 are sequentially added 0.6 g of a 5 wt% phthalazine solution in 2-butanone, 0.74 g of a 20 wt% solution of LOWINOX ^™ 22IB46 in 2-butanone and Finally, 0.85 g of 2-butanone stirred into the PC03-containing silver behenate.

The obtained dispersions are then at a temperature of 30 ° C in a Wet layer thickness of 80 microns on a 100 μm strong Subbed polyethylene terephthalate (PET carrier) aufgerakelt, after which one for several minutes at 40 ° C on the coating bed and then in a hot air oven for 1 hour Dry at 50 ° C leaves, to the photothermographic materials of the COMPARATIVE EXAMPLES 1 and 2.

Pictorial exposure and heat development

• * AgBeh = Silberbehenat.

The photothermographic recording materials of COMPARATIVE EXAMPLES 1 and 2 are then exposed through a test sample in contact with the material in an Agfa-Gevaert ^™ DL 2000 imager with ultraviolet light and then in pressure contact with a heated to a temperature between 95 ° C and 150 ° C Metal block thermally developed. The heat development of the photothermographic recording materials takes place after maximum exposure and without exposure, and the respective optical densities D _max and D _min are measured in the background behind an optical filter with a MacBeth ^™ TR924 densitometer. The optical densities obtained with the photothermographic recording materials of COMPARATIVE EXAMPLES 1 and 2 and the heat development conditions used are listed in Table 1. Table 1:

• * AgBeh = silver behenate.

Out leaves the results unexpectedly see that the photothermographic recording materials COMPARATIVE EXAMPLES 1 and 2 almost no photothermographic Effect, i. no image differentiation, have, even not under the extreme heat development conditions the 30 second Heating at 130 ° C, i.e. if the materials are both silver iodide and the tinting agent Phthalazine, even in a ratio of up to 25.5 mol%, based on the silver behenate (AgBeh).

INVENTIVE EXAMPLE 1

Preparation of an aqueous silver behenate

The dried powder prepared as described in COMPARATIVE EXAMPLES 1 and 2, which contains 4 mol% behenic acid, based on the silver behenate, is pre-dispersed in demineralised water with the anionic dispersants Ultra of ^TM W and Mersolat ^™ H, by high-speed high-speed mixing A rotary mill (rotor-stator mixer) obtained a paste and the resulting dispersion is homogenized at a jet pressure of 400 bar in a MICROFLUIDICS ^™ M-110Y high-pressure microfluidizer to obtain an aqueous dispersion, the 16.7 wt .-% Silver behenate, 0.5 wt .-% behenic acid, 2.1 wt .-% Ultravon ^TM W and 0.203 wt .-% Mersolat ^TM H. The pH of the dispersion is adjusted to about 6.5.

Partial conversion into radiation-sensitive Silver halide and order, drying and development of the photothermographic material

Then be the following ingredients are stirred into 2.62 g each of the prepared dispersions: 1.5 g of a 30 wt .-% solution of BINTER 01 in demineralised water at a pH of 4, 3 g of a 1.22 wt .-% aqueous solution from PC03, giving a ratio of 8 mol% PCO3, based on the silver behenate, corresponds to the in situ conversion of a portion of the silver behenate to silver iodide at a pH of 4, 0.5 g of a 6.57 wt .-% aqueous phthalazine and 1.5 g of a 5.4% by weight aqueous solution solution of R01 at a pH of 4.

The silver behenate silver iodide emulsion obtained is then in a Wet thickness of 90 μm to a 100 microns heavily subbed polyethylene terephthalate support. After drying for several minutes at 40 ° C on In the coating bed, the emulsion layer is heated for 1 h in a hot-air oven at 50 ° C dried.

The pictorial exposure and the heat development of the thus obtained photothermographic recording material of INVENTIVE EXAMPLE 1 are carried out analogously to the procedure of the COMPARATIVE EXAMPLES 1 and 2, where the heat development 5 to 10 s at 105 ° C takes and gets very good pictures with high contrast and good sharpness become. This result proves that photothermographic Recording materials containing both silver iodide and phthalazine Contain, on order from aqueous Media after exposure and heat development have good photothermographic properties while at Photothermographic recording materials containing both silver iodide as phthalazine, when applied from solvent media little or no image differentiation is observed.

INVENTIVE EXAMPLES 2 to 6

For the production the photothermographic recording materials of the INVENTION EXAMPLES 2 to 6 is carried out analogously to the INVENTION EXAMPLE 1, however with the difference that instead of 0.5 g of a 6.57 wt .-% aqueous phthalazine 0.5 g each of an aqueous phthalazine solution in depending on the invention example varying ratio given in Table 2. The also shown in Table 2 phthalazine in the thus obtained Photothermographic recording materials varies between 5 and 30 mol%, based on the silver behenate.

INVENTIVE EXAMPLE 7

For the production of the photothermographic recording material of the INVENTION EXAMPLE 7 becomes analogous to the INVENTION EXAMPLE 2 procedures, but with the difference that instead of the 3 g of a 1.22 wt .-% aqueous PC03 solution 2.7 g of a 1.22 wt .-% aqueous PC03 solution and 0.15 g of a 2.44 wt .-% aqueous PC02 solution be added.

COMPARATIVE EXAMPLE 3

For the production of the photothermographic material of the COMPARATIVE EXAMPLE 3 is proceeded analogously to INVENTION EXAMPLE 1, but with the difference that instead of the 3 g of a 1.22 wt .-% aqueous PC03 solution 3 g of a 1.11 wt .-% PC02 solution be added.

COMPARATIVE EXAMPLE 4

The Preparation of Photothermographic Recording Material of COMPARATIVE EXAMPLE 4 is carried out analogously to the COMPARATIVE EXAMPLE 3, but with the difference that instead of 0.5 g of a 6.57 wt .-% aqueous phthalazine 0.5 g of a 2.6 wt .-% aqueous phthalazine be added. The photothermographic recording material thus obtained contains So 10 mol% phthalazine, based on the Silberbehenatgehalt, compared to 25 mol% phthalazine, based on the silver behenate content, in the Photothermographic recording material of COMPARATIVE EXAMPLE 1 are included.

COMPARATIVE EXAMPLE 5

The Preparation of Photothermographic Recording Material of COMPARATIVE EXAMPLE 5 is carried out analogously to the COMPARATIVE EXAMPLE 1, but with the difference that instead of 0.5 g of a 6.57 wt .-% aqueous phthalazine 0.5 g of demineralized water are added. The thus obtained photothermographic recording material thus contains 0 mol% of phthalazine, based on the silver behenate content, compared to the 25 mol% phthalazine, based on the Silberbehenatgehalt that in the photothermographic Recording material of the INVENTION EXAMPLE 1 are included.

Nachentwicklungsbeständigkeit the photothermographic recording materials of the INVENTION EXAMPLES 1 to 7 and COMPARATIVE EXAMPLES 3 to 5

After imagewise exposure and heat development at 105 ° C for 5 to 10 seconds, the photothermographic recording materials of INVENTION EXAMPLES 1 to 7 and COMPARATIVE EXAMPLES 3 to 5 all exhibit good images with high contrast and good sharpness. The images are then placed on the glass window of a custom built light box described below and the evolution of the density D _min obtained without exposure monitored as a function of time. The results are listed in Table 2 below.

Of the Lightbox is using several equidistant fluorescent lamps stocked, which are arranged such that in the region of the glass window, where the materials to be evaluated in terms of post-development light resistance are exposed, a uniform flow of light of 5,800 lux at a color temperature of 5,000K.

The Results in Table 2 show that in the photothermographic Recording materials of INVENTION EXAMPLES 1 to 7, which radiation sensitive silver halide having at least 80 mole% silver iodide and a diazine compound, i. the phthalazine according to the invention, contain excellent post-development light resistance is obtained while the photothermographic recording materials of the COMPARATIVE EXAMPLES 3 to 5, the radiation-sensitive silver bromide and Phthalazine or radiation-sensitive silver iodide without diazine compound contain a weak post-development light resistance exhibit.

Table 2:

INVENTIVE EXAMPLES 8 to 13

The Preparation of photothermographic recording materials of INVENTIVE EXAMPLES 8 to 13 is analogous to the INVENTION EXAMPLE 2, but with the difference that instead of the 3 g of a 1.22 wt .-% aqueous PC03 solution solutions from other iodide-containing ones listed in Table 3 below Conversion means are used.

After imagewise exposure and heat development at 105 ° C for 5 to 10 seconds in the manner described for INVENTION EXAMPLE 1, the photothermographic recording materials of INVENTION EXAMPLES 8 to 13 all exhibited good images with high contrast and good sharpness. The images are then placed on the glass window of a specially designed light box described above and the evolution of the density D _min obtained without exposure monitored as a function of time. The results are listed in Table 3 below.

• * Iodidumwandlungsmittel.

The results in Table 3 show that the post-development light resistance of the photothermographic recording materials of INVENTION EXAMPLES 8 to 13 containing 8 mol% of silver iodide and 20 mol% of phthalazine of the present invention relative to the silver behenate is limited by the choice of the silver behenate into silver iodide converting agent. Table 3:

• * Iodide conversion agent.

INVENTIVE EXAMPLES 14 to 19

The Preparation of the photothermographic recording material of INVENTIVE EXAMPLES 14 to 19 are analogous to the INVENTION EXAMPLE 2, but with the difference that instead of 1.5 g of 5.44 wt .-% aqueous R01 solution 1.5 g of demineralized water at a pH of 4 can be used.

On the photothermographic recording material are then in a Wet thickness of 30 μm solutions the reducing agent listed in Table 4 below in the solvents also shown in Table 4 below and relationships after which the obtained photothermographic recording materials of the INVENTION EXAMPLES 14 to 19 for several minutes at 40 ° C on the coating bed and then 1 h in a hot air oven at 50 ° C let it dry.

• * wässrige Lösung mit Ultravon^TM W als Dispersionsmittel,
• ° RM = Reduktionsmittel.

After imagewise exposure and heat development in the manner described for INVENTION EXAMPLE 1 and under the heat processing conditions shown in Table 4 below, the photothermographic recording materials of INVENTION EXAMPLES 14 to 19 all exhibited good images with high contrast and good sharpness. The exposed and thermally developed photothermographic materials are then placed on the glass window of a specially designed light box described above and the evolution of the density D _min obtained without exposure monitored as a function of time. The results are listed in Table 4 below. Table 4:

• * aqueous solution with Ultravon ^TM W as dispersing agent,
• ° RM = reducing agent.

The Results in Table 4 show that the post-development light resistance the photothermographic recording materials of the INVENTION EXAMPLES 14 to 19, the 8 mol% of silver iodide and 20 mol% of phthalazine according to the invention, based on the silver behenate, contained only to a small extent the choice of the reducing agent is influenced.

INVENTIVE EXAMPLE 20

The preparation of the photothermographic recording material of INVENTION EXAMPLE 20 is carried out analogously to INVENTION EXAMPLE 1, but with the difference that instead of 0.5 g of a 6.57% by weight aqueous phthalazine solution and 1.5 g of a 5.4 wt. -% aqueous solution of reducing agent R01 2.0 g of demineralized water at a pH of 4 are used. Further, on the silver behenate-containing layer in a wet thickness of 30 microns, a mixture of 0.5 g of a 6.57 wt .-% aqueous phthalazine solution, 1.87 g of a 5.4 wt .-% solution of reducing agent R01, 1.48 g of demineralized water and various drops of an 8.5 wt% solution of Ultra W ^TM . The material thus obtained, containing 20 mol% of phthalazine, based on the silver behenate, is allowed to dry for several minutes at 40 ° C on the coating bed and then for 1 h in a hot air oven at 50 ° C.

After imagewise exposure and heat development in the manner described for INVENTION EXAMPLE 1, the photothermographic recording material has a good image with high contrast and good sharpness. It is then placed on top of the glass window of a specially designed light box described above and the evolution of the density D _min obtained without exposure monitored as a function of time. The results are listed in Table 5 below.

Table 5:

Out The results in Table 5 show that the choice of whether the reducing agent and the diazine compound either directly in the silver behenate-containing layer are incorporated, such as that in the photothermographic recording material of the INVENTION EXAMPLE 2 is the case, or in an aqueous one solution be applied to the silver behenate-containing layer, such as that in the photothermographic recording material of the INVENTION EXAMPLE 20 is the case, it has little influence on the post-development light resistance of these photothermographic recording materials containing 8 mol% of silver iodide and 20 mol% of phthalazine according to the invention, based on the silver behenate.

INVENTIVE EXAMPLES 21 and 22

The Preparation of Photothermographic Recording Material of INVENTIVE EXAMPLE 21 is carried out analogously to the INVENTION EXAMPLE 3, but with the difference that containing on the silver behenate Layer further in a wet thickness of 40 microns, a mixture of 2.0 g of a 3.83 wt .-% aqueous phthalazine, 0.3 g of BINTER 02 and 1.7 g of demineralized water are applied wherein a photothermographic recording material having a overall ratio of phthalazine of 75 mole%, based on the silver behenate content, is obtained.

The Preparation of Photothermographic Recording Material of INVENTIVE EXAMPLE 22 is carried out analogously to the INVENTION EXAMPLE 3, but with the difference that containing on the silver behenate Layer further in a wet thickness of 40 microns, a mixture of 1.5 g of a 3.83 wt .-% aqueous phthalazine, 0.3 g of BIN 02 and 2.2 g of demineralized water are applied wherein a photothermographic recording material having a overall ratio of phthalazine of 60 mol%, based on the silver behenate content, is obtained.

• * ES = Emulsionsschicht.

After drying on the coating bed at 40 ° C for several minutes and then drying in a hot air oven at 50 ° C for 1 hour, the photothermographic recording materials of INVENTION EXAMPLES 21 and 22 are imagewise exposed and thermally developed analogously to the procedure of INVENTION EXAMPLE 1 to obtain good high contrast images and good sharpness. The thus exposed and thermally developed materials are then placed on the glass window of a specially designed light box described above and the evolution of the density D _min obtained without exposure monitored as a function of time. The results are listed in Table 6 below. Table 6:

• * ES = emulsion layer.

Out From the results in Table 6 it can be seen that the presence an additional one Amount of phthalazine in a coating, as in the photothermographic recording materials of INVENTIVE EXAMPLES 21 and 22, only a slight improvement in post-development light resistance of these photothermographic recording materials causes compared to Photothermographic recording material of the INVENTION EXAMPLE 3, the 8 mol% of silver iodide and 15 mol% of phthalazine according to the invention, based on the silver behenate contains.

INVENTIVE EXAMPLE 23

The Preparation of Photothermographic Recording Material of INVENTIVE EXAMPLE 23 is carried out analogously to the INVENTION EXAMPLE 2, but with the difference that instead of 1.5 g of BIN 01 in a weight ratio of 30% in demineralized water with a pH of 4.75 g of a 2 wt .-% aqueous solution of hydroxyalkylcellulose.

After imagewise exposure and heat development in the manner described for INVENTION EXAMPLE 1, a good image with high contrast and good sharpness is obtained. The thus imagewise exposed and thermally developed material is then placed on the glass window of a specially constructed light box described above and the evolution of the density D _min obtained without exposure monitored as a function of time. The results are listed in Table 7 below.

Table 7:

Out It can be seen from the results in Table 7 that the choice of Binder, i. whether a water-dispersible binder (INVENTIVE EXAMPLE 2) or a water-soluble Binders (Invention Example 23) is used in the photothermographic recording materials of the INVENTION EXAMPLES 2 and 23, the 8 mol% of silver iodide and 20 mol% of phthalazine according to the invention, based on the silver behenate, contain the post-development light resistance of these photothermographic recording materials is not affected.

To the detailed description of preferred embodiments according to the invention might It should be clear to the experts in this field that here within the scope of the following claims numerous modifications possible are.

Claims (9)

A process for producing a photothermographic recording material comprising a support and a photoaddressable thermally developable element, the radiation sensitive silver halide in catalytic association with a substantially light insensitive silver salt of a fatty acid, an organic reducing agent for the substantially light insensitive silver salt of a fatty acid in a thermally effective relationship thereto, a surfactant and a water-soluble binder, a water-dispersible binder or a mixture of a water-soluble binder and a water-dispersible binder, said method comprising the steps of: (1) preparing an aqueous dispersion or aqueous dispersions, the radiation-sensitive silver halide, a substantially light-insensitive silver salt of a fatty acid organic reducing agent for the substantially light-insensitive silver salt of a fatty acid and a water-soluble Bi (ii) applying the aqueous dispersion (s) to a support to form a photoaddressable thermally developable element on the support A support characterized in that at least 80 mole% of the radiation-sensitive silver halide is silver iodide and the aqueous dispersion (s) further contains a diazine compound. Process for the preparation of a photothermographic Recording material according to claim 1, characterized the diazine compound is a 1,2-diazine compound or a substituted one 1,2-diazine compound. Process for the preparation of a photothermographic Recording material according to claim 1 or 2, characterized that the diazine compound phthalazine or substituted phthalazine is. Process for the preparation of a photothermographic Recording material according to one of the preceding claims, characterized characterized in that at least 90 mol% of the radiation-sensitive Silver halide is silver iodide. Process for the preparation of a photothermographic Recording material according to one of the preceding claims, characterized characterized in that the photo-addressable heat-developable element with a protective layer is provided. Process for the preparation of a photothermographic Recording material according to one of the preceding claims, characterized characterized in that the photoaddressable thermally developable element further comprises Dye with a maximum absorbency between 600 and 1,100 nm contains. A method of making a photothermographic Recording material according to one of the preceding claims, characterized characterized in that the aqueous (s) Dispersion (s) an aqueous Suspension of particles of a substantially light-insensitive silver salt a fatty acid, by simultaneous dosing of an aqueous solution or suspension of a fatty acid or its salt formed therefrom and an aqueous solution of a silver salt in an aqueous one liquid is produced contains or contain, wherein the dosing of the aqueous solution or suspension of the fatty acid or their silver salt formed therefrom and / or the aqueous solution of the silver salt by the silver ion ratio or anion ratio of the Silver salt in the aqueous liquid is controlled. A photothermographic recording material with a carrier and a photo-addressable heat-developable one Element, the radiation-sensitive silver halide in catalytic Relationship to a substantially light-insensitive silver salt of a Fatty acid, an organic reducing agent for the substantially light-insensitive Silver salt of a fatty acid in a thermally effective relationship thereto and a water-soluble one A binder, a water-dispersible binder or a mixture from a water-soluble Binder and a water-dispersible binder contains, characterized characterized in that at least 80 mol% of the radiation-sensitive Silver halide is silver iodide and the photoaddressable heat developable Element further a surfactant and an optionally substituted Contains phthalazine compound. Photothermographic recording material according to claim 8, characterized in that at least 90 mol% of the radiation-sensitive silver halide is silver iodide.