DE69821593T2 - Photothermographic recording material containing both ex-situ and in-situ photosensitive silver halide and an essentially light-insensitive organic silver salt - Google Patents

Description

technical Field of the Invention

The The present invention relates to a photothermographic recording material with improved sensitivity and improved contrast.

general State of the art

In US-P 3 457 075 discloses a useful sheet material for use in an imaging method, wherein the material with a Exposed photo and then heated over the entire surface and contains a layer that (a) an agent for forming a photosensitive silver halide catalyst and (b) a heat sensitive reactive contains imaging agent, that (1) a water-insoluble silver salt a long chain fatty acid as an oxidizing agent and (2) a reducing agent for silver ions contains, where the oxidation-reduction reaction of this reducing agent which is a visible change is caused by the catalyst is accelerated, wherein the layer is further characterized in that an adequate Amount of at least 0.25 mol%, based on the silver salt of the fatty acid radiation sensitive agent in catalytic proximity to a zulänglichen Proportion of the heat sensitive Means to create a “Gamma infinite "value of at least about 0.5 if the layer is imagewise with exposed to the photo and then developed the image through full-surface heating and wherein the manufacturing process for the sheet material comprises the step in which the silver salt of the fatty acid contains a halide ion source is added under conditions under which a reaction between two elements to form the silver halide catalyst forming agent leads. As a source of halide ions for the conversion of organic silver salts into silver halides the following substances are listed in GB 1 547 326: inorganic Halides, halogen-containing metal complexes, onium halides (for Quaternary example Ammonium halides, quaternary phosphonium halides and tertiary Sulfonium halides), halogenated hydrocarbons, N-halo compounds and other halogen-containing compounds.

In WO 97/48014 is characterized by the steps below Manufacturing process for a photothermographic recording material discloses: (i) providing a carrier, (ii) coating the support with a photo addressable heat developable Element that is an essentially light-insensitive organic silver salt, radiation sensitive silver halide in a catalytic relationship to the essentially light-insensitive organic silver salt Reducing agent in a thermally effective relationship to the essential light-insensitive organic silver salt and a binder contains characterized in that for the preparation of the radiation-sensitive Silver halide an aqueous Emulsion of particles of the substantially light-insensitive organic Silver salt with at least one onium salt with one or more Halide or polyhalide anions react and the photo-addressable heat-developable Element from an aqueous Dispersion medium is applied.

In WO 97/48015 becomes a photothermographic recording material with an out of water Media-loadable, photo-addressable heat-developable element disclosed which is an essentially light-insensitive organic silver salt, radiation sensitive silver halide in a catalytic relationship to substantially light-insensitive organic silver salt, a reducing agent in a thermally effective relationship to the essentially light-insensitive contains organic silver salt and a binder, characterized in that the binder is a water soluble Polymer, a water-dispersible polymer or a mixture of a water soluble Polymer and a water-dispersible polymer contains Particles of the radiation sensitive silver halide are not in the photo addressable developable Bale element and evenly over and between particles of the distributed substantially light-insensitive organic silver salt are and at least 80% by number of the particles one by an electron microscope Transmittance recording determined maximum diameter 40 m.

In US 3,871,887 discloses a method of making a photothermographic composition characterized by the following steps: (A) preparing a dispersion comprising (a) an oxidizing-reducing imaging combination, (i) a silver salt oxidizing agent, and (ii) an organic reducing agent contains (b) ex situ-formed radiation-sensitive silver halide peptized with a synthetic polymer, and (c) contains a cyclic imide toner in (d) a non-gelatin-containing polymeric binder, and (B) adding a sensitizing amount of an iodide salt except for silver iodide salt with the dispersion, the iodide salt being able to increase the radiation sensitivity of the photothermographic composition.

It however, there is a need for photothermographic recording materials with an even higher one Radiation sensitivity than that according to the teaching of WO 97/48014 and WO 97/48015 achievable radiation sensitivity and in particular on photothermographic recording materials, their coating from watery solutions and dispersions can be made. Other desired goals are an improvement in contrast and a decrease in required Amount of radiation sensitive silver halide to reach the required radiation sensitivity in photothermographic Materials based on an essentially light-insensitive organic silver salt, radiation sensitive silver halide in catalytic relation to the organic silver salt and one Reducing agent for the organic silver salt. A decrease in the amount of silver halide would intrinsic stability such materials and thus their sensitivity to radiation (or the amount required to achieve the same radiation sensitivity Silver halide) because of the required amount Stabilizer to achieve acceptable durability before and after exposure and thus that caused by the stabilizer Loss of radiation sensitivity is reduced.

Tasks of present invention

task the present invention is therefore to provide a method for the production of a photothermographic recording material with an improved as a result of coating from an aqueous medium Radiation sensitivity, the photothermographic recording material a photo addressable heat developable Element based on an essentially light-insensitive organic silver salt, radiation sensitive silver halide in catalytic relation to the organic silver salt and one Reducing agent for contains the organic silver salt.

A second object of the present invention is a photothermographic Recording material with improved radiation sensitivity provide a photo-addressable heat-developable element the basis of an essentially light-insensitive organic Silver salt, radiation sensitive silver halide in catalytic Relationship to organic silver salt and a reducing agent for the organic Contains silver salt.

A Another object of the present invention is a recording method for a thermographic having the above improved properties To provide recording material.

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

Short presentation of the present invention

In deviation from US 3,871,887 In which the examples according to the invention show that no noticeable change in the radiation sensitivity is achieved by varying the amount of iodide per mole of radiation-sensitive silver bromide formed ex situ from solvent media coated with solvent media between 0.05 and 0.25 mol, the inventors have Unexpectedly found that the radiation sensitivity of photothermographic imaging elements coated from aqueous media increases markedly with increasing iodide ratio, the optimal iodide ratio being more than 0.25 mol per mol ex-radiation-sensitive silver halide formed.

The above objects according to the invention are achieved by a method characterized by the following steps for producing a photothermographic recording material which is heat-developable under essentially anhydrous conditions (i) providing a support, (ii) preparing one or more aqueous dispersions or solutions which together form an essential light-insensitive organic silver salt, ex situ-formed radiation-sensitive silver halide in catalytic relation to the essentially light-insensitive organic silver salt, a reducing agent in thermally effective relation to the substantially light-insensitive organic silver salt and a binder, (iii) applying the one or more aqueous dispersions or solutions to the carrier Formation of layers which form a photo-addressable heat-developable element after drying, and (iv) drying of the layers, characterized in that the photo-addressable heat-developable element contains between 0.2 and 2.5 moles of radiation-sensitive silver iodide formed in situ per mole of radiation-sensitive silver halide formed ex situ, with particles of the substantially light-insensitive organic silver salt reacting in an aqueous dispersion with an iodide ion source in the ex-situ preparation leaves and as a substantially light-insensitive organic silver salt a silver salt of an organic car bonic acid is used.

Be solved the above objects of the invention also by means of a photothermographic recording material, that can be heat-developed under essentially water-free conditions is and a photo addressable heat developable Element contains which is an essentially light-insensitive organic silver salt, radiation sensitive silver halide in a catalytic relationship to the essentially light-insensitive organic silver salt Reducing agent in a thermally effective relationship to the substantially light-insensitive contains organic silver salt and a binder, characterized in that part of the radiation-sensitive silver halide ex situ and a portion of the radiation sensitive silver halide in situ is formed and contain both parts in separate layers are, the substantially light-insensitive organic silver salt is a silver salt of an organic carboxylic acid.

Be solved the above objects of the invention also by one identified by the steps below Recording method: (i) providing one described above photothermographic recording material, (ii) arranging the recording material nearby an actinic radiation source to which the material is sensitive (iii) imagewise exposure the recording material with the actinic radiation, (iv) arranging of the imagewise exposed Recording material nearby a heat source, (v) heat generation of the imagewise exposed Recording material under essentially water-free conditions and (vi) removal of the heat developed exposed imagewise Recording material from the heat source, characterized in that the substantially light-insensitive organic silver salt Silver salt of an organic carboxylic acid.

preferred embodiments of the present invention are disclosed in the subclaims.

Full Description of the present invention

The The present invention will hereinafter be described by way of examples described, referring to the associated Figure is referenced. Show it:

1 : An electron micrograph at 100,000 × magnification of the dispersion of silver behenate and silver halide formed ex situ during the production of the photothermographic recording material of COMPARATIVE EXAMPLE 6.

2 : An electron micrograph with a magnification of 100,000 × of the dispersion of silver behenate, silver halide formed ex situ and silver iodide formed in the course of the production of the photothermographic recording material according to EXAMPLE 21.

3 : An electron micrograph with a magnification of 100,000 × of the dispersion of silver behenate, ex-formed silver halide, in-situ formed silver iodide and phenyltribromomethylsulfone made during the production of the photothermographic recording material of the invention EXAMPLE 22.

definitions

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

"Substantially insensitive to light" is not to be understood deliberately sensitive to light.

Under “heat developable under essentially anhydrous conditions "is understood in the present invention a warming to a temperature of 80 ° C up to 250 ° C under conditions where the reaction system is almost in equilibrium with water in the air and water for triggering or promoting the reaction particularly or noticeably from the outside of the thermographic recording material supplied becomes. One such condition is described by T. H. James in "The Theory of the Photographic Process ", 4th edition, Macmillan 1977, page 374.

radiation-sensitive silver halide

For photothermographic Recording materials based on aqueous media organic silver salts and reducing agents have been found to by using 0.2 to 2.5 moles of silver iodide formed in situ radiation-sensitive silver halide formed per mole ex situ an unexpected non-additional Increase in radiation sensitivity is achieved. In a preferred one embodiment between 0.3 and 2.0 moles of silver iodide formed in situ per Mol of radiation-sensitive silver halide formed ex situ is used, particularly preferably an amount between 0.3 and 1.5 mol in situ Silver iodide formed per mole of radiation-sensitive silver halide.

electron microscope Radiographs of dispersions from silver behenate, ex situ formed silver halide and in situ formed silver iodide, the in the presence of ex-sensitive radiation-sensitive silver halide produced, show a very different distribution of silver halide particles in the silver behenate-silver halide dispersions than in the case of the dispersions, which are only radiation-sensitive formed ex situ Contain silver halide or silver iodide formed in situ.

In one preferred according to the invention embodiment are the ex-situ radiation-sensitive silver halide and the radiation-sensitive silver iodide formed in situ separate layers in a catalytic relationship to the essential light-insensitive organic silver salt.

In another preferred according to the invention embodiment the radiation-sensitive silver iodide formed in situ situ in the presence of the radiation sensitive formed ex situ Silver halide formed. It turned out that the weakly distributed and aggregated particles of the ex situ radiation-sensitive silver halide formed among them Solve conditions from each other and as a result of Ostwald ripening during the in-situ formation of the radiation-sensitive silver iodide to epitaxial growth notice.

The Radiation sensitive silver halide is preferably in one Relationship, based on the substantially light-insensitive organic silver salt, between 0.1 and 50 mol%, particularly preferably between 3 and 35 mol% and very particularly preferably between 5 and 20 mol% in the photothermographic according to the invention Recording material included.

Formed ex situ radiation sensitive silver halide

In one preferred according to the invention embodiment is the radiation-sensitive formed ex situ Silver halide around silver bromide, silver chloride, silver iodide or one made of silver chloride and / or silver bromide and / or silver iodide composite solid solution.

In another preferred embodiment of the photothermographic according to the invention Materials is the ex-sensitive radiation-sensitive silver halide in a relationship based on the substantially light-insensitive organic silver salt, contain between 0.1 and 35 mol% in the material.

In another preferred embodiment of the photothermographic according to the invention Recording material has at least 80 vol .-% of the particles of silver halide formed ex situ by an electron microscope Radiation recording determined diameters between 50 and 150 nm on.

Ex Radiation-sensitive silver halide formed in situ can any conventional Methods such as that in Research Disclosure No. 17029 released in June 1978, Section I become.

Radiation sensitive formed in situ silver iodide

• – Alkali- und Ammoniumiodide, z. B. KI, NH₄I usw.,
• – Oniumsalze mit Iodid- oder Polyiodidanionen,
• – N-Iodverbindungen usw.

The radiation-sensitive silver iodide formed in situ and used in the photothermographic recording material according to the invention is produced by reacting organic silver salt particles with an iodide ion source in an aqueous medium. Suitable iodide ion-providing substances are:

• - Alkali and ammonium iodides, e.g. B. KI, NH ₄ I etc.,
• Onium salts with iodide or polyiodide anions,
• - N-iodine compounds etc.

Under Onium salts are understood according to the "McGraw-Hill Dictionary of Scientific and Technical Terms ", 4. Edition, edited by SP Parker, McGraw-Hill Book Company, New York (1989) "mentioned definition:" chemical suffix, which is a complex cation ". The iodide or polyiodide onium salts can as Solid or in solution added or by metathesis between a salt with iodide or Polyiodide anions and onium salts with anions other than iodide or polyiodide anions in the aqueous Dispersion of particles of the essentially light-insensitive silver salt be formed.

Preferred according to the invention Onium cations are organophosphonium, organosulfonium and organo nitrogen onium cations, where heterocyclic nitrogenonium (e.g. pyridine), quaternary phosphonium and tertiary Sulfonium cations are preferred.

In the present invention, both polymeric and non-polymeric onium cations are suitable as onium cations. Preferred non-polymeric onium salts for the partial conversion of particles of the substantially light-insensitive organic silver salt into radiation-sensitive silver halides according to the invention are:
the nitrogenonium polyiodides (NC):
NC01 = N-dodecylpyridine iodide
NC02 = tetrabutylammonium iodide
the quaternary phosphonium polyiodides (PC):
PC01 = 3- (triphenylphosphonium) propionic acid iodide
PC02 = methyl triphenylphosphonium iodide
and the tertiary sulfonium polyiodide trimethylsulfonium iodide.

Bromine or Chlorine radical supplying substance

In a preferred embodiment of the photothermographic recording material according to the invention, the photo-addressable heat-developable element further contains a bromine or chlorine radical-providing substance. Suitable substances providing bromine or chlorine radicals are described in JP 50-089018, JP 50-137126, GB 2 006 976, US 3,707,377 , EP-A 631 176, EP-A 605 981, EP-A 600 587, US 4,459,350 . US 5 340 712 . US 4,756,999 . US 4,546,075 . US 4,452,885 and EP-B 223 606. A particularly preferred substance supplying bromine or chlorine radicals is an arylhaloalkylsulfone or heterocyclic haloalkylsulfone. Phenyltribromomethyl sulfone is very particularly preferred.

photo-addressable developable element

The photo-addressable according to the invention developable Contains item an essentially light-insensitive organic silver salt, radiation-sensitive Silver halide in a catalytic relationship to the substantially light-insensitive organic silver salt, a reducing agent in a thermally effective relationship to the essentially light-insensitive organic silver salt and a water-soluble or water-dispersible binder. The element can be a layer structure included, in which the silver halide in a catalytic relationship to the ingredients of the essentially light-insensitive organic Silver salt, the spectral sensitizer, optionally in combination with a super sensitizer, in a sensitizing relationship with the silver halide particles and the other ingredients used in the Heat development process or effective in the 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 tinting agent in a thermally effective relationship to the essentially light-insensitive organic silver salt, d. H. during the heat development process the reducing agent and the possible tinting agent are able to to diffuse substantially light-insensitive organic silver salt.

Significantly insensitive to light organic silver salts

Preferred substantially light-insensitive organic silver salts for use in the photothermographic recording materials according to the invention are silver salts of organic carboxylic acids, e.g. B. silver salts of aromatic carboxylic acids such as silver benzoate, and silver salts of aliphatic carboxylic acids known as fatty acids, in which the aliphatic carbon chain preferably contains at least 12 carbon atoms, e.g. B. silver laurate, silver palmitate, silver stearate, silver hydroxystearate, silver oleate and silver behenate, these silver salts are also referred to as "silver soaps". Silver salts of aliphatic carboxylic acids are particularly preferred for use in the photothermographic recording materials according to the invention. Combinations of different organic silver salts are also suitable for use in the photothermographic materials of the invention.

Preparation of dispersions an organic silver salt

Particles of the silver salts of organic carboxylic acids are prepared by reacting a soluble silver salt with the organic carboxylic acid or a salt formed therefrom. In Research Disclosure No. 17029, published in June 1978, Section II provides an overview of various processes for the production of organic heavy metal salts. To obtain a fine emulsion of an organic heavy metal salt, the synthesis must either be in a medium containing an organic solvent, for example as described in US Pat. No. 3,700,458, or in a mixture of water and a substantially water-insoluble organic solvent, for example in US -P 3 960 908 for silver carboxylates. A suspension of particles of an essentially light-insensitive organic silver salt can be prepared by a process in which a solution or suspension of an organic compound which contains at least one ionizable hydrogen atom or its salt formed therefrom and a solution of a silver salt are metered into a liquid at the same time, as described in EP-a 754 969. If a dispersion is required, any conventional dispersion technique can be used, for example, dispersing in a ball mill, a microfluidizer ^®, a bead mill, etc.

On preferred method for making a dispersion of particles an essentially light-insensitive organic silver salt, which includes silver behenate, in an aqueous Medium for use in the photothermographic recording material according to the invention comprises the following steps: (i) preparation of an aqueous Dispersion containing one or more organic acids, including behenic acid, and contains an anionic surfactant, (ii) substantial neutralization of the organic acids with a watery Alkali, whereby salts of an organic acid, including the salt of behenic acid, are formed and (iii) adding an aqueous solution a silver salt to completely remove the organic acid salts to convert their silver salts, which include silver behenate, characterized in that that the anionic surfactant in a molar ratio, based on the organic Acid, of more than 0.15 used and the silver salt at a rate between 0.025 moles per mole of organic silver salt per minute and 2.25 moles per mole of organic silver salt is added per minute.

Suitable anionic surfactants for use in the process for preparing a dispersion of particles of the substantially light-insensitive organic silver salt in an aqueous medium are:
Surfactant No. 1 = MARLON ^™ A-396, a sodium alkylphenyl sulfonate from Hüls,
Surfactant No. 2 = ammonium 4-dodecylbenzenesulfonate,
Surfactant No. 3 = HOSTAPAL ^™ B, a sodium trisalkylphenyl polyethylene glycol (EO 7-8) sulfate from Hoechst.

organic reducing agent

suitable organic reducing agents for the reduction of the substantially light-insensitive organic heavy metal salts are organic compounds that have at least one active O, N or contain C-bonded hydrogen atom. Particularly usable organic reducing agents for the reduction of the substantially light-insensitive organic silver salt are non-sulfo-substituted 6-membered aromatic or heteroaromatic Ring compounds with at least three substituents, one of which first a hydroxyl group on a first carbon atom and a second one substituted on a second carbon atom Is hydroxyl group or amino group, with three or five ring atoms in a system of conjugated double bonds from the first carbon atom are removed in the compound, wherein (i) the third substituent part a fused carbocyclic or heterocyclic ring system may be (ii) the third substituent or another substituent is not an aryl group or oxoaryl group whose aryl group is represented by a hydroxyl, thiol or amino group is substituted, and (iii) the third substituent or another substituent is a non-sulfo electron attracting one Group is when the second substituent is an amino group.

Especially preferred reducing agents are substituted pyrocatechins or substituted hydroquinones, where 3- (3 ', 4'-dihydroxyphenyl) propionic acid, 3', 4'-dihydroxybutyrophenone, Methyl gallate, ethyl gallate and 1,5-dihydroxynaphthalene in particular to be favoured.

Further suitable reducing agents, in particular for photothermographic recording materials hindered phenols, bisphenols and sulfonamide phenols.

Combinations of reducing agents can also be used, some of which are heated take part in the reduction reaction of the substantially light-insensitive organic silver salt, which includes silver behenate. For example, combinations of reducing agents with sulfonamide phenols are described in the journal "Research Disclosure", February 1979, article 17842, in US Pat. Nos. 4,360,581 and 4,782,004 and in EP-A 423 891. Other examples are combinations of sterically hindered phenols with sulfonyl hydrazide reducing agents as described in US Pat. No. 5,464,738, trityl hydrazides and formylphenyl hydrazides as described in US Pat. No. 5,496,695, trityl hydrazides and formylphenyl hydrazides with various auxiliary reducing agents as described in US Pat. P5,545,505, USP5,545,507 and USP5,558,983, acrylonitrile compounds as described in USP5,545,515 and USP5,635,339, and 2-substituted malondialdehyde compounds as described in USP 5,654,130. Organic reducing metal salts, e.g. Tin stearate have also been used in such reducing agent combinations as described in U.S. Patent Nos. 3,460,946 and 3,547,648. Sterically hindered phenols and bisphenols have themselves been used in such reducing agent combinations as described in U.S. Patent Nos. 4,001,026 and 4,001,026, respectively. U.S. Patent 3,547,648.

The Silver image density depends of the order relationship of the above-defined reducing agent (s) and the above-defined one organic silver salts (s) and should be measured so that when heated to a temperature of more than 100 ° C an optical Density of at least 2.5 can be obtained. Preferably be at least 0.10 moles of reducing agent per mole of organic silver salt used.

During the heat generation The reducing agent must be contained in such a way that it becomes part of the particles of the substantially light-insensitive organic silver salt is able to reduce the substantially light-insensitive organic Effect silver salt.

spectral sensitizer

The photo addressable heat developable Element of the photothermographic recording material according to the invention may, in combination with a supersensitizer, one spectral sensitizer for contain the silver halide which is suitable for the wavelength of the used light source, the near ultraviolet light, visible radiation, z. B. 630 nm, 670 nm etc., or infrared light. The silver halide can with various known dyes such as u. a. cyanine, Merocyanine dyes, styryl dyes, hemicyanine dyes, Oxonol dyes, hemioxonol dyes and xanthene dyes and optionally, especially in the case of sensitization to infrared radiation, spectrally sensitized in the presence of a supersensitizer become. Usable cyanine dyes are those with a basic Ring like a thiazoline ring, an oxazoline ring, a pyrroline ring, a pyridine ring, an oxazole ring, a thiazole ring, a selenazole ring and an imidazole ring. Useful preferred merocyanine dyes are those who except the basic ring described above also has an acid ring like a thiohydantoin ring, a rhodanine ring, an oxazolidinedione ring, a thiazolidinedione ring, a barbituric acid ring, a thiazolinone ring, contain a malononitrile ring and a pyrazolone ring. Both The cyanine and merocyanine dyes described above are those with imino groups or carboxyl groups particularly useful.

supersensitisers

The photothermographic according to the invention Contains recording material optionally a supersensitizer. Preferred supersensitizers are selected from the group consisting of mercapto compounds, disulfide compounds, Stilbene compounds, organoborate compounds and styryl compounds selected.

Binder for the photo addressable developable element

As film forming binder for the photo addressable heat developable Element are suitable for all types of natural, modified natural or synthetic resins or mixtures of such resins, e.g. B. Cellulose derivatives such as ethyl cellulose, cellulose esters, e.g. B. cellulose nitrate, Carboxymethyl cellulose, starch ether, Gallactomannan, polymers derived from α, β-ethylenically 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 a 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.

A particularly suitable polyvinyl butyral with a small amount of vinyl alcohol units is sold by Monsanto, USA, under the trade name BUTVAR ^™ B79 and ensures good adhesion to paper and polyester substrates suitably subbed.

The The layer containing organic silver salt is usually from an organic solvent, in which the binder is dissolved is applied to a support in the form of a sheet or sheet however also from an aqueous Medium containing a water-dispersible binder and / or a water-dispersible Contains binder, be applied.

suitable water-soluble film-forming binders for use in thermographic inventions and photothermographic recording materials are polyvinyl alcohol, Polyacrylamide, polymethacrylamide, polyacrylic acid, polymethacrylic acid, polyvinylpyrrolidone, Polyethylene glycol, proteinaceous binders such as gelatin, modified Gelatins such as phthaloyl gelatin, polysaccharides such as starch, gum arabic and Dextran, and water soluble Cellulose derivatives. A preferred water soluble binder for use in the thermographic according to the invention and photothermographic recording materials is gelatin.

suitable water-dispersible binders for use in the thermographic invention and photothermographic recording materials are all water-insoluble Polymers, e.g. B. water-insoluble Cellulose derivatives, polyurethanes, polyesters, polycarbonates and polymers derived from α, β-ethylenic unsaturated Compounds such as post-chlorinated polyvinyl chloride, partially hydrolyzed Polyvinyl acetate, polyvinyl alcohol, polyvinyl acetals, preferably Polyvinyl butyral, and homopolymers and copolymers made from monomers from the group consisting of vinyl chloride, vinylidene chloride, acrylonitrile, Acrylamides, methacrylamides, methacrylates, acrylates, methacrylic acid, acrylic acid, vinyl esters, Styrenes, dienes and alkenes are formed, or mixtures thereof. It should be noted that there are none with tiny polymer particles clear transition between a polymer dispersion and a polymer solution, causing the smallest particles of the polymer in dissolved form and the slightly larger particles will be in dispersed form.

preferred water dispersible binders for use in the present Invention are water-dispersible film-forming polymers with covalent bound ionic groups from the group consisting of sulfonate, Sulfinate, carboxylate, phosphate, quaternary ammonium groups, tertiary sulfonium groups and quaternary Phosphonium. Other preferred water-dispersible binders for use in the present invention are water dispersible film-forming polymers with covalently bound portions with a or more acid groups.

Water-dispersible Binder with crosslinkable groups, e.g. B. epoxy groups, acetoacetoxy groups and crosslinkable double bonds are also preferred. preferred water-dispersible binders for use in the thermographic invention and photothermographic recording materials are polymeric Latexes. For its use as a latex, the dispersible Polymer preferably has a certain hydrophilic functionality.

The weight ratio from binder to organic silver salt is preferably between 0.2 and 6 and the strength the recording layer preferably between 5 and 50 microns.

thermal solvent

The mentioned above Binders or mixtures thereof can 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" means in the present invention on a non-hydrolyzable organic material that can be used at temperatures below 50 ° C is in the solid state in the recording layer, but at Heating to a temperature of more than 60 ° C in the heated area Plasticizer for the recording layer is and / or as a dissolving liquid for at least one of the redox reagents, e.g. B. the reducing agent for the organic Heavy metal salt, operated.

tint

In order to obtain a neutral black image tone in the upper density zones and neutral gray in the lower density zones, the recording layer preferably contains admixed with the organic ones Heavy metal salts and reducing agents a so-called tinting agent known from thermography or photothermography. Suitable toning agents are the phthalimides and phthalazinones corresponding to the general formulas in US Pat. No. 4,082,901 and the toning agents mentioned in US Pat. Nos. 3,074,809, 3,446,648 and 3,844,797. Other particularly useful toning agents are the heterocyclic toner compounds of the benzoxazinedione or naphthoxazinedione type, as described in GB-P 1 439 478, US-P 3 951 660 and US-P 5 599 647. One particularly suitable for use in combination with polyhydroxybenzene reducing agents a suitable toner compound is the 3,4-dihydro-2,4-dioxo-1,3,2H-benzoxazine described in US Pat. No. 3,951,660.

antihalation

Except the The above-mentioned ingredients can be the photothermographic according to the invention Recording material antihalation dyes or screen dyes contain the light that penetrates the radiation sensitive layer has, absorb and thus prevent reflection of this light, whereby the light near ultraviolet light, visible radiation, e.g. B. 630 nm, 670 nm etc., or infrared light. Such dyes can into the photo addressable heat developable Element or in any other layer of the photothermographic according to the invention Recording material can be incorporated.

surfactants

In of the present invention for the preparation of dispersions of particles of the substantially light-insensitive Silver salt of an organic carboxylic acid in aqueous media and for the dispersion of water-dispersible binders such as polymeric latices in aqueous Media uses non-ionic, cationic or anionic surfactants become. According to the invention also a mixture of non-ionic and anionic surfactants, from non-ionic and cationic surfactants, from cationic and anionic surfactants or non-ionic, cationic and anionic surfactants in question.

In an embodiment of the invention the surfactant is an anionic surfactant. In a preferred according to the invention embodiment the anionic surfactant is a sulfonate, e.g. As alkyl, aryl, alkaryl or Aralkyl sulfonate, with alkyl and alkaryl sulfonate being particularly preferred become.

In a further embodiment according to the invention the ionic surfactant is a non-ionic surfactant, for example Alkyl, aryl, alkaryl or aralkyl polyethoxyethanols. Nonionic preferred according to the invention Surfactants are alkoxypolyethoxyethanols and alkaryloxypolyethoxyethanols.

Further ingredients

In addition to the ingredients mentioned above, the photo-addressable heat-developable element may contain other ingredients such as free fatty acids, surfactants, antistatic agents, e.g. B. non-ionic antistatic agents with a fluorocarbon group such as. B. in F ₃ C (CF ₂ ) ₆ CONH (CH ₂ CH ₂ O) H, silicone oil, e.g. B. BAYSILONE ^™ Oil A (trade name of BAYER AG, GERMANY), ultraviolet light absorbing compounds, white light reflecting and / or ultraviolet reflecting pigments, silica, fine polymer particles [e.g. B. poly (methyl methacrylate) particles] and / or optical brighteners.

carrier

The carrier for the photothermographic according to the invention Recording material can be translucent, translucent or opaque, e.g. B. white light reflective, and is preferably a thin, flexible support z. B. paper or polyethylene-coated paper or a film made of translucent Resin, e.g. B. from a cellulose ester, e.g. B. cellulose triacetate, Polypropylene, polycarbonate or polyester, e.g. B. polyethylene terephthalate. For example, the recording material can be a paper carrier substrate include the white light May contain reflective pigments, if necessary also in an intermediate layer between the recording material and the paper carrier substrate can be embedded.

The support may be in the form of a sheet, ribbon or web and is subbed if necessary to improve adhesion to the heat sensitive recording layer applied thereon. The carrier may be made from an opacified resin composition, e.g. B. from polyethylene terephthalate, which is made opaque by means of pigments and / or micro-cavities, and / or is optionally coated with an opaque pigment / binder layer and can be referred to as synthetic paper, or is a paper-like film. More precise information about such carriers are the EP 194 106 and 234 563 and U.S. Patent Nos. 3,944,699, 4,187,113, 4,780,402 and 5,059,579. When using a translucent support, the support can be colorless or colored, such as. B. colored blue.

It can one or more backing layers applied to physical properties such as curling and Control antistatic protection.

outer layer

The outer layer of the recording material can be in various embodiments of the present invention, the outer layer of the heat sensitive Elements, one on the heat sensitive Element attached protective layer or one on the heat sensitive Element opposite Side of the carrier attached layer.

protective layer

To a preferred embodiment of the photothermographic according to the invention Recording material is the photo addressable heat developable Element with a protective layer, through the local Deformation of the photo-addressable heat-developable element avoided, the abrasion resistance improved and direct contact with components of the heat generating device is prevented.

The Contains protective layer preferably a binder that is soluble in solvents, dispersible in solvents, water soluble or can be water dispersible. Preferred as solvent-soluble binders in particular polycarbonates, as described in EP-A 614 769. For the Protective layer, however, is preferred water-soluble or water-dispersible Binder because their application is made from an aqueous casting composition and mixing the protective layer with that immediately below lying layer by using a solvent-soluble or dispersible binder in the immediately below Layer can be avoided.

A protective layer according to the invention may further contain a thermally fusible particle, optionally together with a lubricant on the protective layer, as in WO 94/11199. In a preferred embodiment, the protective layer contains at least one solid lubricant with a melting point below 150 ° C and at least a fluid Lubricants in a binder, at least one of the lubricants a phosphoric acid derivative is.

water-soluble or water-dispersible binder for the outer layer

To an embodiment of the invention can the outer layer of the recording material is a water-soluble or water-dispersible Binder or a mixture of a water-soluble and water-soluble Contain binders. Suitable water-soluble binders for the outer layer are for example gelatin, polyvinyl alcohol, cellulose derivatives or other polysaccharides, hydroxyethyl cellulose, hydroxypropyl cellulose etc., being curable Preferred binder and polyvinyl alcohol is particularly preferred. Suitable water-dispersible binders are polymeric latices.

crosslinking agent for the outer layer

The outer layer according to the invention can be networked. For crosslinking come crosslinking agents such as those in WO 95/12495 for protective layers described in question, e.g. B. tetraalkoxysilanes, polyisocyanates, Aldehydes, zirconates, titanates, melamine resins etc., with tetraalkoxysilanes such as tetramethyl orthosilicate and tetraethyl orthosilicate are preferred become.

matting agent for the outer layer

The outer layer of the recording material according to the invention may contain a matting agent. Suitable matting agents are described in WO 94/11198 et al. a. Talc particles, and possibly protrude from the outer layer out.

lubricant for the outer layer

Solid or liquid lubricants or combinations thereof are suitable for improving the Sliding properties of the recording materials according to the invention.

Usable according to the invention solid lubricants are polyolefin waxes, ester waxes, polyolefin-polyether block copolymers, Amide waxes, polyglycols, fatty acids, Fatty alcohols, natural Waxes and solid phosphoric acid derivatives. Preferred solid lubricants are thermally melting particles like those described in WO 94/11199.

Usable according to the invention liquid Lubricants are fatty acid esters such as glycerol trioleate, sorbitan monooleate and sorbitan trioleate, silicone oil derivatives and phosphoric acid derivatives.

Antistatic layer

In a preferred embodiment of the recording material according to the invention is on the outer layer on the not coated with the photo addressable heat sensitive element Antistatic layer attached. Suitable antistatic layers are described in EP-A 444 326, 534 006 and 644 456, US-P 5 364 752 and 5 472 832 and DOS 4125758.

coating techniques

The Application of any layer of the recording material according to the invention can be done by any coating technique, such as. B. 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, UNITED STATES.

Photothermographic recording method

The Exposure of the photothermographic according to the invention Materials can be emitted with radiation with a wavelength between the wavelengths of X-rays and a wavelength of 5 nm, the image either by pixel exposure with a focused light source like a cathode ray tube, one Ultraviolet laser, a laser for visible light, an infrared laser like a He / Ne laser, one Infrared laser diode, the z. B. 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 object itself or an image of the object with a suitable exposure source, such as B. 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 an acceptable heating period of recording materials to the development temperature, z. B. contact heating, radiation heating, microwave heating etc.

applications

The photothermographic according to the invention Recording materials can for the Creation of both review images and oversight copies be used. For such applications become the carrier translucent or opaque, d. H. a white light having a reflective aspect. For example, a Paper carrier substrate be used, the white light May contain reflective pigments, if necessary also in an intermediate layer between the recording material and the paper carrier substrate are embedded. When using a translucent support the carrier colorless or colored, z. B. blue colored, his.

at Hard copies are used for photothermographic recording materials on a white opaque straps, in the graphic area, black-screen transparencies are used as Mask and in medical diagnostics find black screen transparencies at with a viewing device working testing techniques widespread application.

• – als organisches Silbersalz: AgB = Silberbehenat,
• – als Bindemittel: R16875 = Typ R16875, eine Phthaloylgelatine von ROUSSELOT, LATEX 01 = ein Latex eines Terpolymers von 47,5 Gew.-% Butadien, 47,5 Gew.-% Methylmethacrylat und 5 Gew.-% Itakonsäure,
• – R01 = 3-(3',4'-Dihydroxyphenyl)-propionsäure als Reduktionsmittel,
• – TA01 = Phthalazin als Tönungsmittel, und
• – BMPS = Phenyltribrommethylsulfon.

The following inventive and comparative examples illustrate the present invention. The percentages and ratios in these examples are by weight unless otherwise noted. In addition to the ingredients already mentioned, the following ingredients are used in these comparative examples according to the invention:

• - as organic silver salt: AgB = silver behenate,
• As binder: R16875 = type R16875, a phthaloyl gelatin from ROUSSELOT, LATEX 01 = a latex of a terpolymer of 47.5% by weight butadiene, 47.5% by weight methyl methacrylate and 5% by weight itaconic acid,
• R01 = 3- (3 ', 4'-dihydroxyphenyl) propionic acid as reducing agent,
• - TA01 = phthalazine as a tinting agent, and
• - BMPS = phenyltribromomethyl sulfone.

EXAMPLES OF THE INVENTION 1 & 2 and COMPARATIVE EXAMPLES 1 & 2

Single-jet production of silver behenate dispersions in an aqueous medium without use an organic solvent

• i) 136,2 g (0,4 Mol) Behensäure werden unter Rühren bei einer Geschwindigkeit von 310 TpM mit einem Typhoon-Rührer mit einem Durchmesser von 80 mm in einem Gefäss mit einem Durchmesser von 200 mm in 549 ml einer 10%igen Lösung von Tensid Nr. 1 und 662 g entmineralisiertem Wasser bei einer Temperatur von 80°C dispergiert,
• ii) anschließend werden 188 ml einer 2-molaren wässrigen Lösung von Natriumhydroxid bei einer Geschwindigkeit von 310 TpM mit einem Typhoon-Rührer mit einem Durchmesser von 80 mm bei einer Temperatur von 80°C und über 10 Minuten hinweg in das Gefäss mit einem Durchmesser von 200 mm eingerührt, um eine klare Lösung, die als Hauptbestandteil Natriumbehenat enthält, zu erhalten,
• iii) anschließend werden 360 ml einer 1-molaren wässrigen Silbernitratlösung bei einer Geschwindigkeit von 310 TpM mit einem Typhoon-Rührer mit einem Durchmesser von 80 mm bei einer Temperatur von 80°C und über 4,5 Minuten hinweg in das Gefäss mit einem Durchmesser von 200 mm eingerührt, um das Natriumbehenat völlig in Silberbehenat umzuwandeln.

The Type I aqueous silver behenate dispersion used in INVENTION EXAMPLES 1 & 2 and COMPARATIVE EXAMPLES 1 & 2 is prepared as follows:

• i) 136.2 g (0.4 mol) of behenic acid are stirred with a Typhoon stirrer with a diameter of 80 mm in a vessel with a diameter of 200 mm in 549 ml of a 10% solution while stirring at a speed of 310 rpm of surfactant No. 1 and 662 g of demineralized water dispersed at a temperature of 80 ° C,
• ii) 188 ml of a 2 molar aqueous solution of sodium hydroxide are then introduced into the vessel with a diameter of at a rate of 310 rpm with a Typhoon stirrer with a diameter of 80 mm at a temperature of 80 ° C. and for 10 minutes 200 mm stirred in to obtain a clear solution containing sodium behenate as the main component,
• iii) Then, 360 ml of a 1 molar aqueous silver nitrate solution at a speed of 310 rpm with a Typhoon stirrer with a diameter of 80 mm at a temperature of 80 ° C. and over 4.5 minutes into the vessel with a diameter of Stirred 200 mm to completely convert the sodium behenate to silver behenate.

The aqueous thus obtained Contains silver behenate dispersion 8.15% by weight of silver behenate and 2.78% by weight of surfactant No. 1.

Ex situ manufacture of radiation sensitive silver halide

The Preparation of the type 01 silver halide emulsion containing 3.11% by weight Silver halide particles consisting of 97 mol% silver bromide and 3 mol% silver iodide with a weight average particle size of 50 nm and 0.47% R16875 contains as a dispersant in demineralized water according to conventional Silver halide manufacturing techniques as described, for example in T.H. James, "The Theory of the Photographic Process ", 4th Edition, Macmillan Publishing Co. Inc., New York (1977), Section 3, pages 88-104, with at least 80% by number of the particles by an electron microscope transmission determined diameter between 40 m and 100 nm.

Gießdispersionen

The Preparation of the casting dispersions for the photothermographic recording materials of the EXAMPLES OF THE INVENTION 1 & 2 and COMPARATIVE EXAMPLES 1 & 2 done with stirring, optionally the silver halide dispersion of type 01 in the amount given in Table 1 with a silver behenate dispersion Type I is mixed, then optionally potassium iodide as a 3.63 wt% aqueous solution in the molar amount specified in Table 1 and then LATEX 01 as a 30 wt .-% aqueous Dispersion in a weight corresponding to the amount of silver behenate be added and then TA01 as a 5.6 wt .-% aqueous solution in an amount of 20 mol%, based on the amount of silver behenate, and finally R01 as a 5.6 wt% aqueous solution in an amount of 45 mol%, based on the amount of silver behenate, be added.

Coating with the photo addressable developable element

The silver behenate / silver halide dispersion for the photothermographic recording material of the relevant EXAMPLE is doctored onto a subbed polyethylene terephthalate support with a thickness of 100 μm with a doctor blade setting of 120 μm. The photothermographic recording material thus obtained is then left on the coating bed for a few minutes at 40 ° C. and then Dry in a hot air oven at 40 ° C for 1 hour to obtain a photo-addressable heat-developable element with a silver behenate layer weight of about 5 g / m ² .

Pictorial exposure and heat development

The photothermographic materials of INVENTION EXAMPLES 1 & 2 and COMPARATIVE EXAMPLES 1 & 2 are then exposed through a test sample in contact with the material in an Agfa-Gevaert ^™ DL 2000 exposer equipped with a V405 filter (the filter being UV transmissive -Wavelengths between 390 and 440 nm), after which they are heated for 5 s on a metal block heated to 105 ° C. in order to obtain a very good image with high contrast and good sharpness.

image analysis

The maximum and minimum optical densities of the prints obtained with the recording materials of INVENTION EXAMPLES 1 & 2 and COMPARATIVE EXAMPLES 1 & 2 and the difference representing the contrast obtained are measured in the table below, behind a Macbeth ^™ TR924 densitometer optical filter 1 for the photothermographic recording materials of INVENTION EXAMPLES 1 & 2 and COMPARATIVE EXAMPLES 1 & 2.

Table 1

From the results in Table 1 it can be seen that the photothermographic recording materials according to EXAMPLES 1 & 2, in which the in-situ formation of silver halide with potassium iodide takes place in the presence of ex-formed silver halide, with an unexpected additional increase in sensitivity, that is, an additional reduction in the exposure intensity set to obtain a density D = D _min + 1.0, compared to the photothermographic recording materials of COMPARATIVE EXAMPLE 1, which only contain radiation-sensitive silver halide formed in situ, and of COMPARATIVE EXAMPLE 2, which only form ex situ contain radiation sensitive silver halide. In addition, it was found that the radiation sensitivity of the photothermographic material of INVENTION EXAMPLE 2, which contains 1.0 mole of silver iodide formed in situ per mole of silver halide formed ex situ, is markedly better than the radiation sensitivity that is obtained with the photothermographic material of INVENTION EXAMPLE 1, containing 0.5 mole of silver iodide formed in situ per mole of silver halide formed ex situ.

EXAMPLES OF THE INVENTION 3 to 7 and COMPARATIVE EXAMPLE 3

The Production of the photothermographic recording materials of the EXAMPLES OF THE INVENTION 3 to 7 and COMPARATIVE EXAMPLE 3 is carried out analogously to the photothermographic Recording materials of INVENTION EXAMPLES 1 & 2 and the COMPARATIVE EXAMPLES 1 & 2 except for the data in Table 2 below.

The photothermographic processing of the photothermographic recording materials OF THE INVENTION EXAMPLES 3 to 7 and COMPARATIVE EXAMPLE 3 is also analogous to that EXAMPLES OF THE INVENTION 1 & 2 and the COMPARATIVE EXAMPLES 1 & 2. The results are listed in Table 2 below.

Table 2

From the results in Table 2, it can be seen that the photothermographic recording materials of EXAMPLES 3 to 7 in which the in-situ formation of silver halide with 3- (triphenylphosphonium) propionic acid iodide (PC01) takes place in the presence of ex-formed silver halide , with an additional increase in sensitivity, ie an additional reduction in the exposure intensity set to obtain a density D = D _min + 1.0, compared to the photothermographic recording materials of COMPARATIVE EXAMPLE 3 which contain radiation-sensitive silver halide formed only with PC01 in situ, and of COMPARATIVE EXAMPLE 2. In addition, the results obtained with the photothermographic recording materials of INVENTION EXAMPLES 4 to 7 show that with a constant degree of in-situ silver halide formation, an increase in sensitivity and contrast (D _max - D _min ) goes hand in hand with increasing amount of exhaled silver halide.

EXAMPLES OF THE INVENTION 8 to 10 and COMPARATIVE EXAMPLE 4

Single-jet production a type II silver behenate / silver halide dispersion in one aqueous Medium without the use of an organic solvent

The preparation of the aqueous silver behenate / silver halide dispersion of type II used in INVENTION EXAMPLES 8 to 10 and in COMPARATIVE EXAMPLE 4 is carried out analogously to the aqueous silver behenate dispersion of type I, but with the difference that it essentially consists of Sodium behenate solution [between steps (ii) and (iii)] 45.43 g of the silver halide dispersion of type 01 can be added. The aqueous silver behenate dispersion thus obtained contains 8.03% by weight of silver behenate, 2.74% by weight of surfactant 1, 0.27% by weight of AgBr _0.97 I _0.03 and 0.04% of R16875.

Pouring dispersions and application of these Gießdispersionen

The Preparation and application of the casting dispersions is carried out analogously the production of the photothermographic recording material OF THE INVENTION EXAMPLES 1 & 2 and the COMPARATIVE EXAMPLES 1 & 2, except for the data in Table 3.

Photothermographic processing

The photothermographic processing of the photothermographic recording materials OF THE INVENTION EXAMPLES 8 to 10 and COMPARATIVE EXAMPLE 4 is also analogous to that EXAMPLES OF THE INVENTION 1 & 2 and the COMPARATIVE EXAMPLES 1 & 2. The results are listed in Table 3 below.

Table 3

From the results in Table 3 it can be seen that the photothermographic recording materials according to EXAMPLES 8 to 10, in which the in situ formation of silver halide with 3- (triphenylphosphonium) propionic acid iodide (PC01) or potassium iodide in the presence of during the Silver behenate synthesis present ex situ formed silver halide takes place with a higher sensitivity, ie a lower exposure intensity set to obtain a density D = D _min + 1.0, and a higher contrast (D _max - D _min ) compared to the photothermographic recording material of the COMPARATIVE EXAMPLE 4, which contains only ex-situ radiation sensitive silver halide formed during silver behenate synthesis. In addition, the radiation sensitivity of the photothermographic materials of INVENTION EXAMPLES 8 to 10 increases with an increasing ratio of silver iodide formed in situ per mole of silver halide formed ex situ, ie of 0.28 J / m ² for the photothermographic material of INVENTION EXAMPLE 8, the 0 , 28 moles of silver halide formed in situ per mole of silver halide formed ex situ contains up to 0.13 J / m ² for the photothermographic material of INVENTION EXAMPLE 8, which contains 1.0 mole of silver halide formed in situ per mole of silver halide formed ex situ.

EXAMPLES OF THE INVENTION 11 to 20 and COMPARATIVE EXAMPLE 5

The photothermographic recording materials of EXAMPLES 11 to 20 and COMPARATIVE EXAMPLE 5 are produced analogously to the photothermographic recordings DRAWING MATERIALS OF THE INVENTION EXAMPLES 1 & 2 and COMPARATIVE EXAMPLES 1 & 2, except as for the data in Table 4 below. The BMPS is added as an aqueous dispersion unless otherwise noted.

The photothermographic processing of the photothermographic recording materials OF THE INVENTION EXAMPLES 11 to 20 and COMPARATIVE EXAMPLE 5 is also analogous to that EXAMPLES OF THE INVENTION 1 & 2 and the COMPARATIVE EXAMPLES 1 & 2. The results are together with the results for the photothermographic Recording material of INVENTION EXAMPLE 1 in the following Table 4 listed.

Table 4

It can be seen from the results in Table 4 that the photothermographic recording materials of EXAMPLES 1, 11 and 19, in which the in-situ formation of silver halide with potassium iodide takes place in the presence of ex-formed silver halide, with an additional increase in sensitivity , that is, an additional reduction in the exposure intensity set to obtain a density D = D _min + 1.0, compared to the photothermographic recording material of COMPARATIVE EXAMPLE 5, which contains only ex-radiation-sensitive silver halide, and the photothermographic recording material of COMPARATIVE EXAMPLE 1, which contains only radiation sensitive silver halide formed in situ. By adding BMPS as in the case of the photothermographic recording materials of EXAMPLES 12 to 18 in accordance with the invention and 20, an additional increase in sensitivity, ie a decrease in the exposure intensity set to obtain a density D = D _min + 1.0, and a strong contrast enhancement (D _max - D _min ) is obtained. The sensitivity and the contrast increase with increasing BMPS ratio, the BMPS ratio being increased up to approximately 15 mol%, based on the silver behenate content.

EXAMPLES OF THE INVENTION 21 to 27 and COMPARATIVE EXAMPLE 6

Ex situ production of radiation sensitive silver halide

The Production of the silver halide emulsions of types 02 to 05 takes place analogous to that used in the production of photothermographic materials OF THE INVENTION EXAMPLES 1 & 2 and the COMPARATIVE EXAMPLES 1 & 2 used silver halide emulsion of type 01, except what the differences in composition, silver halide ratio and given in Table 5 R16875 ratio affects.

Table 5

The Production of the photothermographic recording materials of the EXAMPLES OF THE INVENTION 21 to 27 and COMPARATIVE EXAMPLE 6 is analogous to that EXAMPLES OF THE INVENTION 1 & 2 and the COMPARATIVE EXAMPLES 1 & 2, except for the data in Table 4 below. The BMPS is called watery Dispersion added.

electron microscope Radiographs showing the influence of in-situ silver iodide formation and the additional Influence of BMPS on a dispersion of silver behenate and ex situ show formed silver halide

1 FIG. 4 shows an electron micrograph at a magnification of 100,000 × (1 cm = 100 nm) of the dispersion of silver behenate and silver halide formed ex situ during the production of the photothermographic recording material of COMPARATIVE EXAMPLE 6.

2 shows an electron micrograph with a magnification of 100,000 × (1 cm = 100 nm) of the in 1 Dispersion of silver behenate and ex situ formed silver halide, to which 3.7 mol% of potassium iodide, based on the silver behenate content, has been added, as is the case with the preparation of the photothermographic recording material of EXAMPLE 21 according to the invention. From a comparison of the 1 and 2 it is clearly evident that the small black clusters of silver halide particles that are found in 1 are visible as large agglomerations in the dispersion in which in 2 dispersion shown are smaller and better dispersed.

3 shows an electron micrograph with a magnification of 100,000 × (1 cm = 100 nm) of the dispersion of silver behenate and silver halide formed ex situ, which has a slightly higher silver halide ratio than in 1 and to which 4.0 mol% of potassium iodide, based on the silver behenate content, has been added, as in the case of 2 The dispersion shown is the case and to which an additional 8.20 mol% of BMPS, based on the silver behenate content, has been added, as is the case in the production of the photothermographic recording material of EXAMPLE 22 according to the invention. From a comparison of the 2 and 3 it is clearly evident that in the 3 shown Dispersion a significant further reduction in silver halide aggregation has occurred compared to that in 2 dispersion shown and consequently the silver halide particles are dispersed even better.

The photothermographic processing of the photothermographic recording materials OF THE INVENTION EXAMPLES 21 to 27 and COMPARATIVE EXAMPLE 6 is also analogous to that EXAMPLES OF THE INVENTION 1 & 2 and the COMPARATIVE EXAMPLES 1 & 2. The results are listed in Table 6 below.

From the results in Table 6 it can be seen that the photothermographic recording materials according to EXAMPLES 21 to 27, in which the in-situ formation of silver halide with potassium iodide takes place in the presence of ex-formed silver halide, with a marked increase in sensitivity, ie a reduction in the exposure intensity set to obtain a density D = D _min + 1.0 compared to the photothermographic recording material of COMPARATIVE EXAMPLE 6, which contains only ex-radiation-sensitive silver halide. By adding BMPS, an additional increase in sensitivity, ie a reduction in the exposure intensity set to obtain a density D = D _min + 1.0, and an additional increase in contrast (D _max -D _min ) are obtained. The sensitivity and the contrast increase with all of the dispersions containing silver halide formed ex situ with increasing BMPS ratio, regardless of the composition of the silver halide.

Table 6

EXAMPLES OF THE INVENTION 28 & 29 and COMPARATIVE EXAMPLES 7 & 8

Preparation of the silver behenate dispersion of type III

To prepare the silver behenate for the silver behenate dispersion of type III, 34 g (0.1 mol) of behenic acid are dissolved in 340 ml of 2-propanol at 65 ° C., the behenic acid is dissolved in the by adding 400 ml of a 0.25 molar aqueous sodium hydroxide solution stirred behenic acid solution in sodium behenate and finally 250 ml of a 0.4 molar aqueous silver nitrate solution are added, whereby the silver behenate precipitates. The precipitate is filtered off and then with a mixture of 10 vol .-% 2-propanol and 90 vol% demineralized water to remove residual sodium nitrate. The silver behenate is then dried at 45 ° C. for 12 h.

To prepare the silver behenate dispersion of type III used in the preparation of the photothermographic recording materials of COMPARATIVE EXAMPLE 7 and INVENTION EXAMPLE 28, the dried silver behenate powder with the anionic dispersant surfactant No. 1 is dispersed in demineralized water, and after thorough mixing, to obtain a homogeneous mixture with a Microfluidizer ^® a finely divided and stable dispersion containing 20 wt .-% silver behenate and 2.0 wt .-% surfactant No. 1 is obtained. The pH of the dispersion obtained is adjusted to about 6.5.

manufacturing Type IV silver behenate

to Preparation of the silver behenate for the type IV dispersion will add the required amount of behenic acid 60 ° C below vigorous stir dissolved in 2-butanone and then at a temperature between 56 and 60 ° C demineralized water is added to the maintained reactor temperature, after which the behenic acid in a molar ratio of 0.1 by adding an aqueous solution of sodium hydroxide with vigorous Stir in one between 56 and 60 ° C kept reactor temperature converted into 110.9 mol of sodium behenate and finally the sodium behenate is converted to silver behenate by taking vigorous stir at a reactor temperature of 55 ° C initially over 55 minutes 55.45 Moles of silver nitrate as a 1.67 molar aqueous solution and then over 15 minutes 55.45 mol of silver nitrate was added as a 1.67 molar aqueous solution become. The final one weight ratio of 2-butanone in the suspension mixture of 2-butanone and water is 45%.

To prepare the type IV silver behenate dispersion used in COMPARATIVE EXAMPLE 8 and INVENTION EXAMPLE 29, the dried silver behenate with surfactant No. 1 is dispersed in demineralized water, after a rapid mixing to obtain a predispersion and homogenization with a Microfluidizer ^® a finely divided dispersion containing 20% by weight of silver behenate and 2.0% by weight of surfactant No. 1. The pH of the dispersion obtained is adjusted to about 6.5.

The Production of the photothermographic recording materials of the EXAMPLES OF THE INVENTION 28 & 29 and the COMPARATIVE EXAMPLES 7 & 8 takes place analogously to the photothermographic recording materials OF THE INVENTION EXAMPLES 1 & 2 and the COMPARATIVE EXAMPLES 1 & 2, except for the data in Table 7 below. The photothermographic processing of the photothermographic recording materials OF THE INVENTION EXAMPLES 28 & 29 and the COMPARATIVE EXAMPLES 7 & 8 is also carried out analogously to the EXAMPLES 1 & 2 and the COMPARATIVE EXAMPLES 1 & 2. The results are listed in Table 7 below.

Table 7

From the results in Table 7 it can be seen that the photothermographic recording materials of EXAMPLES 28 & 29, both of which are prepared using a silver behenate dispersion prepared under different water and solvent conditions, and in which the in situ formation of silver halide with PC01 in the presence of silver halide formed ex situ, with a noticeable increase in sensitivity, ie a reduction in the exposure intensity set to obtain a density D = D _min + 1.0, and a noticeable increase in contrast (D _max - D _min ) the photothermographic recording materials of the corresponding COMPARATIVE EXAMPLES 7 and 8, which only contain radiation-sensitive silver halide formed ex situ.

EXAMPLE OF THE INVENTION 30 and COMPARATIVE EXAMPLE 9

The Production of the photothermographic recording materials of the EXAMPLE OF THE INVENTION 30 and COMPARATIVE EXAMPLE 9 is carried out analogously to the photothermographic Recording materials of INVENTION EXAMPLES 1 & 2 and the COMPARATIVE EXAMPLES 1 & 2 except for the data in Table 8 below and with the difference that the photo-addressable heat-developable Element of the photothermographic recording material of the EXAMPLE OF THE INVENTION 30 is a double layer element, one layer of which in Silver halide formed in situ with PC01 and the other layer ex contains silver halide formed in situ.

The photothermographic processing of the photothermographic recording materials of the EXAMPLE OF THE INVENTION 30 and COMPARATIVE EXAMPLE 9 is also analogous to that EXAMPLES OF THE INVENTION 1 & 2 and the COMPARATIVE EXAMPLES 1 & 2. The results are together with those of the COMPARATIVE EXAMPLE 4 listed in Table 8 below.

Table 8

From the results in Table 8, it can be seen that the photothermographic recording materials of INVENTION 30, which contain two photoaddressable heat-developable layers containing radiation sensitive silver halide formed in situ with PC01 or silver halide formed ex situ, with an additional increase in sensitivity, ie an additional reduction in the exposure intensity set to obtain a density D = D _min + 1.0, as well as an additional increase in the contrast (D _max - D _min ) compared to the sensitivity and the contrast of the photothermographic materials of COMPARATIVE EXAMPLES 4 and 9, wherein the individual layers contain the photoaddressable element of the photothermographic material of INVENTION EXAMPLE 30.

COMPARATIVE EXAMPLES 10 to 12 and EXAMPLES OF THE INVENTION 31 and 32

The Production of the photothermographic recording materials of the COMPARATIVE EXAMPLES 10 to 12 and the INVENTION EXAMPLES 31 and 32 are carried out analogously to the photothermographic recording materials of COMPARATIVE EXAMPLE 7 and OF THE INVENTION EXAMPLE 28, except for the data in Table 9 below and with the difference that the phthalazine from the composition is omitted.

The photothermographic processing of the photothermographic recording materials of COMPARATIVE EXAMPLES 10 to 12 and OF THE INVENTION EXAMPLES 31 & 32 is done also analogous to the EXAMPLES 1 & 2 and the COMPARATIVE EXAMPLES 1 & 2. The Results are listed in Table 9 below.

Table 9

From the results in Table 9, it can be seen that the photothermographic recording materials of COMPARATIVE EXAMPLES 10 to 12, which contain less than 0.2 mole of silver iodide formed in situ per mole of silver halide and are coated from aqueous media, have a much lower sensitivity than that photothermographic recording materials of the EXAMPLES 31 and 32 which contain more than 0.2 mol of silver iodide formed in situ per mol of silver halide and are coated from aqueous media. This is a deviation from the teaching of the US 3,871,887 , in which the results for photothermographic materials coated from solvent media do not vary between 0.05 and 0.25 moles of silver iodide per mole of silver halide.

To Knowledge of the preferred embodiments described in detail The present invention will differ to those skilled in the art Modifications to the description of the invention open, without of the invention, in the following claims deviate defined protection area.

Claims (11)

A process characterized by the following steps for producing a photothermographic recording material which is heat-developable under essentially anhydrous conditions: (i) providing a support, (ii) preparing one or more aqueous dispersions or solutions which together form a substantially light-insensitive organic silver salt, ex situ formed radiation-sensitive silver halide in a catalytic relationship with the substantially light-insensitive organic silver salt, a reducing agent in a thermally effective relationship with the substantially light-insensitive organic silver salt and a binder, (iii) applying the one or more aqueous dispersions or solutions to the support to form layers which after Drying form a photo-addressable heat-developable element, and (iv) drying the layers, characterized in that the photo-addressable heat-developable element between Contains 0.2 and 2.5 moles of radiation-sensitive silver iodide formed in situ per mole of radiation-sensitive silver halide formed ex-situ, with particles of the substantially light-insensitive organic silver salt being reacted in an aqueous dispersion with an iodide ion source in the ex-situ preparation and as substantially light-insensitive organic silver salt a silver salt of an organic carboxylic acid is used. A method for producing a photothermographic recording material according to claim 1, characterized in that the ex-situ formed radiation-sensitive silver halide and the in-situ formed radiation-sensitive silver iodide in separate layers in a catalytic relationship to the essential light-insensitive organic silver salt. Process for producing a photothermographic Recording material according to claim 1, characterized in that the radiation-sensitive silver iodide formed in situ in the presence of the radiation-sensitive silver halide formed ex situ is formed. Process for producing a photothermographic Recording material according to one of the preceding claims, characterized characterized in that the radiation-sensitive formed ex situ Silver halide, silver bromide, silver chloride, silver iodide or a composed of silver chloride and / or silver bromide and / or silver iodide Is mixed crystal. Process for producing a photothermographic Recording material according to one of the preceding claims, characterized characterized in that the photo-addressable heat-developable element further contains a source of bromine or chlorine radicals. Process for producing a photothermographic Recording material according to claim 5, characterized in that the source of bromine or chlorine radicals is phenyltribromomethylsulfone is. Process for producing a photothermographic Recording material according to one of the preceding claims, characterized characterized in that the radiation sensitive silver halide in a relationship between 0.1 and 50 mol%, based on the substantially light-insensitive organic silver salt, in the photothermographic recording material is included. Process for producing a photothermographic Recording material according to one of the preceding claims, characterized characterized in that the radiation-sensitive formed ex situ Silver halide in a ratio between 0.1 and 35 mol%, based on the substantially light-insensitive organic silver salt, in the photothermographic recording material is included. Process for producing a photothermographic Recording material according to one of the preceding claims, characterized characterized that the source of bromine radicals in one relationship between 1 and 50 mol%, based on the substantially light-insensitive organic silver salt, in the photothermographic recording material is included. Photothermographic recording material, the is heat developable under substantially anhydrous conditions and a photo addressable heat developable Element contains which is an essentially light-insensitive organic silver salt, radiation sensitive silver halide in a catalytic relationship to substantially light-insensitive organic silver salt, a reducing agent in a thermally effective relationship to the essentially light-insensitive contains organic silver salt and a binder, characterized in that part of the radiation-sensitive silver halide ex situ and a portion of the radiation sensitive silver halide in situ is formed and both parts are contained in separate layers, the substantially light-insensitive organic silver salt Silver salt of an organic carboxylic acid. One identified by the steps below Recording method: (i) providing a photothermographic Recording material according to one of claims 1 to 10, (ii) arranging the recording material in the vicinity of an actinic radiation source, across from who is sensitive to the material, (iii) imagewise exposure of the recording material with the actinic radiation, (iv) arranging the imagewise exposed Recording material nearby a heat source, (v) heat generation of the imagewise exposed Recording material under essentially water-free conditions and (vi) removal of the heat developed exposed imagewise Recording material from the heat source, characterized in that the substantially light-insensitive organic silver salt Silver salt of an organic carboxylic acid.