Classifications

• • G—PHYSICS
  • G03—PHOTOGRAPHY; CINEMATOGRAPHY; ANALOGOUS TECHNIQUES USING WAVES OTHER THAN OPTICAL WAVES; ELECTROGRAPHY; HOLOGRAPHY
  • G03C—PHOTOSENSITIVE MATERIALS FOR PHOTOGRAPHIC PURPOSES; PHOTOGRAPHIC PROCESSES, e.g. CINE, X-RAY, COLOUR, STEREO-PHOTOGRAPHIC PROCESSES; AUXILIARY PROCESSES IN PHOTOGRAPHY
  • G03C1/00—Photosensitive materials
  • G03C1/494—Silver salt compositions other than silver halide emulsions; Photothermographic systems ; Thermographic systems using noble metal compounds
  • G03C1/498—Photothermographic systems, e.g. dry silver
  • G03C1/49809—Organic silver compounds
• • G—PHYSICS
  • G03—PHOTOGRAPHY; CINEMATOGRAPHY; ANALOGOUS TECHNIQUES USING WAVES OTHER THAN OPTICAL WAVES; ELECTROGRAPHY; HOLOGRAPHY
  • G03C—PHOTOSENSITIVE MATERIALS FOR PHOTOGRAPHIC PURPOSES; PHOTOGRAPHIC PROCESSES, e.g. CINE, X-RAY, COLOUR, STEREO-PHOTOGRAPHIC PROCESSES; AUXILIARY PROCESSES IN PHOTOGRAPHY
  • G03C1/00—Photosensitive materials
  • G03C1/005—Silver halide emulsions; Preparation thereof; Physical treatment thereof; Incorporation of additives therein
  • G03C1/035—Silver halide emulsions; Preparation thereof; Physical treatment thereof; Incorporation of additives therein characterised by the crystal form or composition, e.g. mixed grain
• • G—PHYSICS
  • G03—PHOTOGRAPHY; CINEMATOGRAPHY; ANALOGOUS TECHNIQUES USING WAVES OTHER THAN OPTICAL WAVES; ELECTROGRAPHY; HOLOGRAPHY
  • G03C—PHOTOSENSITIVE MATERIALS FOR PHOTOGRAPHIC PURPOSES; PHOTOGRAPHIC PROCESSES, e.g. CINE, X-RAY, COLOUR, STEREO-PHOTOGRAPHIC PROCESSES; AUXILIARY PROCESSES IN PHOTOGRAPHY
  • G03C1/00—Photosensitive materials
  • G03C1/494—Silver salt compositions other than silver halide emulsions; Photothermographic systems ; Thermographic systems using noble metal compounds
  • G03C1/498—Photothermographic systems, e.g. dry silver
• • G—PHYSICS
  • G03—PHOTOGRAPHY; CINEMATOGRAPHY; ANALOGOUS TECHNIQUES USING WAVES OTHER THAN OPTICAL WAVES; ELECTROGRAPHY; HOLOGRAPHY
  • G03C—PHOTOSENSITIVE MATERIALS FOR PHOTOGRAPHIC PURPOSES; PHOTOGRAPHIC PROCESSES, e.g. CINE, X-RAY, COLOUR, STEREO-PHOTOGRAPHIC PROCESSES; AUXILIARY PROCESSES IN PHOTOGRAPHY
  • G03C1/00—Photosensitive materials
  • G03C1/494—Silver salt compositions other than silver halide emulsions; Photothermographic systems ; Thermographic systems using noble metal compounds
  • G03C1/498—Photothermographic systems, e.g. dry silver
  • G03C1/49836—Additives
  • G03C1/49863—Inert additives, e.g. surfactants, binders
• • G—PHYSICS
  • G03—PHOTOGRAPHY; CINEMATOGRAPHY; ANALOGOUS TECHNIQUES USING WAVES OTHER THAN OPTICAL WAVES; ELECTROGRAPHY; HOLOGRAPHY
  • G03C—PHOTOSENSITIVE MATERIALS FOR PHOTOGRAPHIC PURPOSES; PHOTOGRAPHIC PROCESSES, e.g. CINE, X-RAY, COLOUR, STEREO-PHOTOGRAPHIC PROCESSES; AUXILIARY PROCESSES IN PHOTOGRAPHY
  • G03C1/00—Photosensitive materials
  • G03C1/494—Silver salt compositions other than silver halide emulsions; Photothermographic systems ; Thermographic systems using noble metal compounds
  • G03C1/498—Photothermographic systems, e.g. dry silver
  • G03C1/4989—Photothermographic systems, e.g. dry silver characterised by a thermal imaging step, with or without exposure to light, e.g. with a thermal head, using a laser
• • G—PHYSICS
  • G03—PHOTOGRAPHY; CINEMATOGRAPHY; ANALOGOUS TECHNIQUES USING WAVES OTHER THAN OPTICAL WAVES; ELECTROGRAPHY; HOLOGRAPHY
  • G03C—PHOTOSENSITIVE MATERIALS FOR PHOTOGRAPHIC PURPOSES; PHOTOGRAPHIC PROCESSES, e.g. CINE, X-RAY, COLOUR, STEREO-PHOTOGRAPHIC PROCESSES; AUXILIARY PROCESSES IN PHOTOGRAPHY
  • G03C1/00—Photosensitive materials
  • G03C1/005—Silver halide emulsions; Preparation thereof; Physical treatment thereof; Incorporation of additives therein
  • G03C1/015—Apparatus or processes for the preparation of emulsions
  • G03C2001/0156—Apparatus or processes for the preparation of emulsions pAg value; pBr value; pCl value; pI value
• • G—PHYSICS
  • G03—PHOTOGRAPHY; CINEMATOGRAPHY; ANALOGOUS TECHNIQUES USING WAVES OTHER THAN OPTICAL WAVES; ELECTROGRAPHY; HOLOGRAPHY
  • G03C—PHOTOSENSITIVE MATERIALS FOR PHOTOGRAPHIC PURPOSES; PHOTOGRAPHIC PROCESSES, e.g. CINE, X-RAY, COLOUR, STEREO-PHOTOGRAPHIC PROCESSES; AUXILIARY PROCESSES IN PHOTOGRAPHY
  • G03C1/00—Photosensitive materials
  • G03C1/005—Silver halide emulsions; Preparation thereof; Physical treatment thereof; Incorporation of additives therein
  • G03C1/035—Silver halide emulsions; Preparation thereof; Physical treatment thereof; Incorporation of additives therein characterised by the crystal form or composition, e.g. mixed grain
  • G03C2001/03594—Size of the grains
• • G—PHYSICS
  • G03—PHOTOGRAPHY; CINEMATOGRAPHY; ANALOGOUS TECHNIQUES USING WAVES OTHER THAN OPTICAL WAVES; ELECTROGRAPHY; HOLOGRAPHY
  • G03C—PHOTOSENSITIVE MATERIALS FOR PHOTOGRAPHIC PURPOSES; PHOTOGRAPHIC PROCESSES, e.g. CINE, X-RAY, COLOUR, STEREO-PHOTOGRAPHIC PROCESSES; AUXILIARY PROCESSES IN PHOTOGRAPHY
  • G03C2200/00—Details
  • G03C2200/36—Latex
• • G—PHYSICS
  • G03—PHOTOGRAPHY; CINEMATOGRAPHY; ANALOGOUS TECHNIQUES USING WAVES OTHER THAN OPTICAL WAVES; ELECTROGRAPHY; HOLOGRAPHY
  • G03C—PHOTOSENSITIVE MATERIALS FOR PHOTOGRAPHIC PURPOSES; PHOTOGRAPHIC PROCESSES, e.g. CINE, X-RAY, COLOUR, STEREO-PHOTOGRAPHIC PROCESSES; AUXILIARY PROCESSES IN PHOTOGRAPHY
  • G03C2200/00—Details
  • G03C2200/43—Process

Definitions

• the present invention relates to a photothermographic recording material comprising a photo-addressable thermally developable element coatable from aqueous media.
• thermography is a recording process wherein images are generated by the use of thermal energy.
• thermography three approaches are known:
• Thermographic materials of type 1 can be rendered photothermographic by incorporating a photosensitive agent which after exposure to UV, visible or IR light is capable of catalyzing or participating in a thermographic process bringing about changes in colour or optical density.
• photothermographic materials are the so called “Dry Silver” photographic materials of the 3M Company, which are reviewed by D.A. Morgan in “Handbook of Imaging Science”, edited by A.R. Diamond, page 43, published by Marcel Dekker in 1991.
• US-P 3,152,904 discloses an image reproduction sheet which comprises a radiation-sensitive heavy metal salt which can be reduced to free metal by a radiation wave length between an X-ray wave length and a five microns wave length and being distributed substantially uniformly laterally over the sheet, and as the image forming component an oxidation-reduction reaction combination which is substantially latent under ambient conditions and which can be initiated into reaction by the free metal to produce a visible change in colour comprising an organic silver salt containing carbon atoms and different from the heavy metal salt as an oxidizing agent and in addition an organic reducing agent containing carbon atoms, the radiation-sensitive heavy metal salt being present in an amount between about 50 and about 1000 parts per million of the oxidation- reduction reaction combination.
• relatively light stable organic compounds such as the substituted pyrazolidones , the substituted and non-substituted hydroxylamines e.g. phenyl hydroxylamine and benzyl hydroxylamine, aminophenols e.g. N-methyl paraminophenol sulfate, the dihydric phenols e.g. hydroquinone and catechol, aromatic esters e.g. methyl gallate, and aromatic diamines e.g. phenylene diamine.
• US-P 4,144,072 discloses the following representative selection of preferred reducing agents for use with photothermographic materials based on silver halide/organic silver salt/reducing agent-systems: mono-, bis-, tris- or tetrakis- phenols, mono- or bis-naphthols, di- or polyhydroxynaphthalenes, di- or polyhydroxybenzenes , hydroxymonoethers , ascorbic acids, 3- pyrazolines , pyrazolones, reducing saccharides, phenylenediamines , hydroxylamines, reductones, hydroxamic acids, hydrazides, amidoximes, n-hydroxyureas, and the like; polyphenols such as the bisphenols used in the 3M Dry SilverTM materials, sulfonamide phenols such as used in the Kodak DacomaticTM materials, and naphthols being particularly preferred.
• This production method is very inefficient as the organic silver salt after formation in water has to be separated and dried before dispersion in a solvent medium, is environmentally unsound as evaporation of solvent takes place during the coating process and it involves lengthy utilization of plant during the preparation of the organic silver salt dispersion and coating requires costly plant due to the need for solvent explosion prevention measures and solvent recovery to prevent solvent emission to the environment.
• US-P 4,123,274 attempts to remedy this deficiency by disclosing a photothermographic element coatable from aqueous media comprising a support having thereon in reactive association (a) photosensitive silver halide, (b) an image-forming combination comprising (i) a silver salt of a 3-amino-l ,2 ,4- mercaptotriazole represented by the formula:
• the described photothermographic materials can contain a variety of silver halide developing agents, especially organic silver halide developing agents. Combinations of organic silver halide developing agents can be especially useful. For example, a combination of a pyrazolidone developing agent with an ascorbic acid developing agent can be useful.
• silver halide developing agents are useful including, for instance, polyhydroxy- benzenes , such as hydroquinone, alkyl-substituted hydroquinones, including tertiary butylhydroquinone, methylhydroquinone, 2,5- dimethylhydroquinone, and 2 ,6-dimethylhydroquinone; catechol and pyrogallol developing agents; chloro-substituted hydroquinones such as chlorohydroquinone of dichlorohydroquinone; alkoxyhydroquinones such as methoxyhydroquinone or ethoxyhydroquinone; aminophenol reducing agents such as 2 ,4-diaminophenols and methylaminophenols ; ascorbic developing agents such as ascorbic acid, ascorbic acid ketals and ascorbic acid derivatives; 3-pyrazolidone developing agents such as i-phenyl-3-pyrazolidone and 4-methyl-4-hydroxymethyl- 1-phen
• phenylenediamine developing agents such as paraphenylenediamine and the like.
• Especially useful developing agents are those which are hydroquinone, ascorbic acid, pyrogallol, gallic acid ester and phenylenediamine silver halide developing agents and combinations of these developing agents.”
• the following reducing agents were used in the invention examples of US-P 4,123,274: hydroquinone, tertiary butylhydroquinone and ascorbic acid.
• the photothermographic recording materials of US-P 4,123,274 have the disadvantages of requiring thermal development temperatures: 145 to 200°C for 30s and producing images with a red-brown tone, which is prohibitive for medical or graphics images, whereas silver behenate-based materials require considerably lower development temperatures, 90 to 120°C for 5 to 20s, and produce images with a blacker tone.
• the invention of US-P 4.529,689 attempts to remedy this deficiency by disclosing a photothermographic film composition
• a photothermographic film composition comprising (a) a substantially light-insensitive silver sulfinate, (b) a photographic silver halide emulsion, (c) a developing (reducing) agent, and (d) a binder; characterized in that the silver sulfinate is selected from the group consisting of silver hexadecylsulfinate, silver dodecylsulfinate, silver nonylsulfinate, silver 3-phenylpropylsulfinate, and silver cyclohexylsulfinate. and wherein the binder is a latex.
• the reducing agents used in the invention examples of this patent were 4-methyl-1-phenyl- pyrazolidin-3-one and 4-hydroxymethyl-4-methyl-1-phenyl-pyrazolidin- 3-one with 4,4-dimethyl-l-phenyl-pyrazolidin-3-one, 1-phenyl- pyrazolidin-3-one, hydroquinone, hydroquinone monosulfonate, ascorbic acid, p-aminophenol sulfate, dodecyl gallate and N-benzyl- p-aminophenol being additionally mentioned in the detailed description of this patent.
• US-P 4,504,575 discloses a photothermographic film comprising a silver salt as physical developer, a silver halide as photocatalyst, and a binder, wherein the improvement comprises using a light- insensitive silver sulfonate as the physical developer in combination with an organic base and wherein the silver sulfonate is silver dodecylsulfonate or silver hexadecylsulfonate.
• the reducing agents used in the invention examples of this patent were hydroquinone monosulfonate and hydroquinone with no further reducing agents being mentioned in the detailed description of this patent.
• It is a second object of the invention to provide a photothermographic recording material comprising a photo-addressable thermally developable element based on a substantially light- insensitive silver salt of an organic carboxylic acid, photosensitive silver halide in catalytic association therewith and an organic reducing agent for the silver salt of an organic carboxylic acid, which is produceable without necessitating intermediate drying of the silver salt of an organic carboxylic acid acid.
• It is another object of the invention to provide a photothermographic recording material comprising a photo-addressable thermally developable element based on a substantially light- insensitive silver salt of an organic carboxylic acid, photosensitive silver halide in catalytic association therewith and an organic reducing agent for the silver salt of an organic carboxylic acid, which is coatable from an aqueous medium.
• a photothermographic recording material comprising a support and a photo- addressable thermally developable element comprising photosensitive silver halide in catalytic association with a substantially light- insensitive silver salt of an organic carboxylic acid, an organic reducing agent for the substantially light-insensitive silver salt of an organic carboxylic acid in thermal working relationship therewith and a binder, characterized in that the binder is water soluble or water dispersible and the reducing agent is a non-sulfo- substituted 6-membered aromatic or heteroaromatic ring compound with at least three substituents one of which is a hydroxy group at a first carbon atom and a second of which is a hydroxy or amino-group substituted on a second carbon atom one, three or five ring atoms removed in a system of conjugated double bonds from the first carbon atom in the compound, in which (i) the third substituent may be part of an annelated carbocyclic or heterocyclic ring system; (ii) the third substituent
• a process is also provided for producing a photothermographic recording material, as referred to above, comprising the steps of: (i) producing a suspension of particles of a substantially light- insensitive silver salt of an organic carboxylic acid; (ii) producing an aqueous dispersion or aqueous dispersions containing ingredients necessary for photothermographic image formation; (iii) coating the aqueous dispersion or aqueous dispersions onto a support.
• a photothermographic recording process comprising the steps of: (i) image-wise exposing a photothermographic recording material, as referred to above, to a source of actinic radiation to which the photothermographic recording material is sensitive; and (ii) thermally developing said image-wise exposed photothermographic recording material.
• FIGURE 1 shows a transmission electron micrograph at a magnification of 50,000x of the silver behenate/silver bromide dispersion produced in the course of the preparation of invention example 24.
• aqueous for the purposes of the present invention includes mixtures of water with water-miscible organic solvents such as alcohols e.g. methanol, ethanol, 2-propanol, butanol, iso-amyl alcohol, octanol, cetyl alcohol etc; glycols e.g. ethylene glycol; glycerine; N-methyl pyrrolidone; methoxypropanol; and ketones e.g. 2-propanone and 2-butanone etc.
• alcohols e.g. methanol, ethanol, 2-propanol, butanol, iso-amyl alcohol, octanol, cetyl alcohol etc
• glycols e.g. ethylene glycol
• glycerine N-methyl pyrrolidone
• methoxypropanol and ketones e.g. 2-propanone and 2-butanone etc.
• a photothermographic recording material comprising a support and a photo- addressable thermally developable element comprising photosensitive silver halide in catalytic association with a substantially light- insensitive silver salt of an organic carboxylic acid, an organic reducing agent for the substantially light-insensitive silver salt of an organic carboxylic acid in thermal working relationship therewith and a binder, characterized in that the binder is water soluble or water dispersible and the reducing agent is a non-sulfo- substituted 6-membered aromatic or heteroaromatic ring compound with at least three substituents one of which is a hydroxy group at a first carbon atom and a second of which is a hydroxy or amino-group substituted on a second carbon atom one, three or five ring atoms removed in a system of conjugated double bonds from the first carbon atom in the compound, in which (i) the third substituent may be part of an annelated carbocyclic or heterocyclic ring system; (ii) the third substituent may be part of an
• a system of conjugated double bonds is meant a succession of alternating single and double bonds in the sense of the definition of conjugated double bonds given in the "Concise Chemical and Technical Dictionary, Fourth Edition", edited by H. Bennett and published by Edward Arnold in 1986: Two double bonds separated by a single bond”.
• the reducing agents of the present invention may also be used in the photothermographic recording materials of the present invention together with other reducing agents according to the present invention or with reducing agents outside the present invention.
• the ring atoms of the non-sulfo-substituted 6-membered aromatic or heteroaromatic ring compound consist of nitrogen and carbon ring atoms and the non-sulfo-substituted 6-membered aromatic or heteroaromatic ring compound is annelated with an aromatic or heteroaromatic ring system.
• non-sulfo-substituted 6- membered aromatic or heteroaromatic ring compound is substituted with one or more of the following substituents which may also be substituted: alkyl, alkoxy, carboxy, carboxy ester, thioether, alkyl carboxy, alkyl carboxy ester, aryl, sulfonyl alkyl, sulfonyl aryl, formyl, oxo-alkyl and oxo-aryl.
• the non-sulfo-substituted 6-membered aromatic or heteroaromatic ring compound is a substituted catechol or a substitued hydroquinone.
• the non-sulfo-substituted 6-membered aromatic or heteroaromatic ring compound is selected from the group consisting of 3- (3 ' ,4 * -dihydroxyphenyl)propionic acid, 3 ' ,4' -dihydroxy- butyrophenone, methyl gallate, ethyl gallate and 1 ,5-dihydroxy- naphthalene.
• the reducing agent must be present in such a way that it is able to diffuse to the substantially light-insensitive particles of a silver salt of an organic carboxylic acid so that reduction of the substantially light-insensitive silver salt of an organic carboxylic acid can take place.
• the reducing agent may be present in the same layer as the substantially light-insensitive silver salt of an organic carboxylic acid, in an adjacent layer or in a layer with a reducing agent- permeable spacer layer between the layer containing the reducing agent and that containing the silver salt of an organic carboxylic acid.
• the concentration of reducing agent is chosen to ensure optimum imaging properties, which is usually about one molar equivalent of reducing group (i.e. -OH, -NH or -SH) per mole of the silver salt of an organic carboxylic acid, but can be more or less.
• Suitable reducing agents according to the present invention are:
• REDU 02 methylhydroquinone
• REDU 03 t-butylhydroquinone
• REDU 04 methoxyhydroquinone also cited together with REDU 01 in the description of US-P 4,123,274;
• REDU 05 3- (3 ' ,4' -dihydroxyphenyl)propionic acid
• REDU 06 (3 ' ,4' -dihydroxyphenyl)acetic acid
• REDU 07 3 ,4-dihydroxybenzoic acid
• REDU 08 methyl 3 ,4-dihydroxy-5-methoxybenzoate
• REDU 09 methyl 3 ,4-dihydroxy-5-toluenesulfonylbenzoate
• REDU 11 3,5-di-t-butyl-catechol
• REDU 12 4-phenylcatechol REDU 13 2,5-dihydroxybenzoic acid
• REDU 14 ethyl 2,5-dihydroxybenzoate
• REDU 15 ethyl gallate
• REDU 16 1-methyl-3-oxy-pentyl gallate
• REDU 18 3 ,3 ,3 ' ,3 ' -t
• auxiliary reducing agents are e.g. sterically hindered phenols, that on heating become reactive partners in the reduction of the substantially light-insensitive silver salt of an organic carboxylic acid such as silver behenate, such as described in US-P 4,001,026; or are bisphenols, e.g. of the type described in US-P 3,547,648.
• the auxiliary reducing agents may be present in the imaging layer or in a polymeric binder layer in thermal working relationship thereto.
• auxiliary reducing agents are sulfonamidophenols corresponding to the following general formula :
• Aryl represents a monovalent aromatic group
• Arylene represents a bivalent aromatic group, having the -OH group preferably in para-position to the -S0 2 -NH- group.
• auxiliary reducing agents that may be used in conjunction with the above mentioned primary reducing agents are sulfonyl hydrazide reducing agents such as disclosed in US-P 5,464,738, trityl hydrazides and formyl-phenyl-hydrazides such as disclosed in US-P 5,496,695 and organic reducing metal salts, e.g. stannous stearate described in US-P 3,460,946 and 3,547.648.
• sulfonyl hydrazide reducing agents such as disclosed in US-P 5,464,738, trityl hydrazides and formyl-phenyl-hydrazides such as disclosed in US-P 5,496,695
• organic reducing metal salts e.g. stannous stearate described in US-P 3,460,946 and 3,547.648.
• the photo-addressable thermally developable element comprises a binder comprising a water- soluble binder, water-dispersible binder or a mixture of a water soluble binder and a water-dispersible binder.
• a binder comprising a water- soluble binder, water-dispersible binder or a mixture of a water soluble binder and a water-dispersible binder.
• the binder is a polymer latex.
• the binder is a polymer comprising monomer units selected from the group consisting of a diene-monomer and a methacrylate.
• the binder is a polymer comprising monomer units selected from the group consisting of styrene and an acrylate.
• the water-dispersible binder can be any water-insoluble polymer e.g. water-insoluble cellulose derivatives, polymers derived from ⁇ . ⁇ -ethylenically unsaturated compounds such as polyvinyl chloride, after-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 that are made from polyvinyl alcohol as starting material in which only a part of the repeating vinyl alcohol units may have reacted with an aldehyde, preferably polyvinyl butyral, copolymers of acrylonitrile and acrylamide, polyacrylic acid esters, polymethacrylic acid esters, polystyrene and polyethylene or mixtures thereof.
• water-insoluble polymer e.g. water-insoluble cellulose derivatives, poly
• a particularly suitable polyvinyl butyral containing a minor amount of vinyl alcohol units is marketed under the trade name BUTVAR B79 of Monsanto USA and provides a good adhesion to paper and properly subbed polyester supports. It should be noted that there is no clear cut transition between a polymer dispersion and a polymer solution in the case of very small polymer particles resulting in the smallest particles of the polymer being dissolved and those slightly larger being in dispersion.
• Suitable water-soluble polymers are: polyvinyl alcohol, polyacrylamide, polyacrylic acid, polymethacrylic acid, polyethyleneglycol, proteins, such as gelatin and modified gelatins such as phthaloyl gelatin, polysaccharides, such as starch, gum arabic and dextran and water-soluble cellulose derivatives.
• plasticizers can be incorporated into the polymers, water-miscible solvents can be added to the dispersion medium and mixtures of water-soluble polymers, mixtures of water- dispersible polymers, or mixtures of water-soluble and water- dispersible polymers may be used.
• the photo-addressable thermally developable element comprises a substantially light- insensitive silver salt of an organic carboxylic acid, photosensitive silver halide in catalytic association therewith and an organic reducing agent in thermal working relationship with the substantially light-insensitive silver salt of an organic carboxylic acid and a water soluble or water-dispersible binder.
• the element may comprise a layer system with the silver halide in catalytic association with the substantially light-insensitive silver salt of an organic carboxylic acid, spectral sensitizer optionally together with a supersensitizer in intimate sensitizing association with the silver halide particles and the other ingredients active in the thermal development process or pre- or post-development stabilization of the element being in the same layer or in other layers with the proviso that the organic reducing agent and the toning agent, if present, are in thermal working relationship with the substantially light-insensitive silver salt of an organic carboxylic acid i.e. during the thermal development process the reducing agent and the toning agent, if present, are able to diffuse to the substantially light-insensitive silver salt of an organic carboxylic acid.
• Preferred substantially light-insensitive silver salts of organic carboxylic acids produced using the process according to the present invention and used in the photothermographic materials, according to the present invention are silver salts of organic carboxylic acids having as their organic group: aryl, aralkyl, alkaryl or alkyl.
• organic carboxylic acids having as their organic group: aryl, aralkyl, alkaryl or alkyl.
• Silver salts of modified aliphatic carboxylic acids with thioether group as described e.g. in GB-P 1,111,492, may likewise be used to produce a thermally developable silver image.
• the substantially light-insensitive silver salt of an organic carboxylic acid is a silver salt of a fatty acid.
• substantially light-insensitive silver salt of an organic carboxylic acid for the purposes of the present invention also includes mixtures of silver salts of organic carboxylic acids.
• the binder to silver salt of an organic carboxylic acid weight ratio is preferably in the range of 0.2 to 6, and the thickness of the recording layer is preferably in the range of 1 to 50 ⁇ m. Production of particles of silver salt of an organic carboxylic acid
• Particles of the silver salts of organic carboxylic acids are prepared by the reaction of a soluble silver salt with the organic carboxylic acid or a salt thereof.
• the suspension of particles of a substantially light-insensitive silver salt of an organic carboxylic acid is produced by simultaneous metered addition of an aqueous solution or suspension of an organic carboxylic acid, or its salt, and an aqueous solution of a silver salt to an aqueous liquid and the metered addition of the aqueous solution or suspension of the organic carboxylic acid or its salt; and/or the aqueous solution of said silver salt is regulated by the concentration of silver ions or the concentration of anions of the silver salt in the aqueous liquid.
• This metered addition may be regulated by varying the rate of addition of the aqueous solution or suspension of the organic carboxylic acid or its salt; and/or the rate of addition of the aqueous solution of the silver salt so as to maintain the value of a physical parameter, that significantly changes upon the addition of the aqueous solution or suspension of the organic carboxylic acid or its salt and/or the aqueous solution of the silver salt to the aqueous liquid, at a particular value predetermined for a particular moment in the process.
• the value of the physical parameter used to regulate the addition of the aqueous solution or suspension of an organic carboxylic acid or its salt and/or the aqueous solution of the silver salt to the aqueous liquid may vary during the course of the production process.
• the physical parameter used to regulate the metered addition of the aqueous solution or suspension of the organic carboxylic acid or its salt; and/or the aqueous solution of the silver salt, according to the present invention may be the concentration of silver ions or the concentration of anions of the silver salt in the aqueous liquid.
• Other physical parameters that may be used to regulate the metered addition of the aqueous solutions are, for example, the electrical conductivity of the suspending medium, the dielectric constant of the suspending medium, the density of the suspending medium, the pH of the suspending medium etc.
• the temperatures of the aqueous solution or suspension of the organic carboxylic acid or its salt; the aqueous solution of the silver salt; and the aqueous liquid are determined by the required characteristics of the particles; and may be kept constant or may be varied during the synthesis of the silver salt of a organic carboxylic acid again depending upon the required characteristics of the particles.
• the aqueous liquid for suspending the particles may contain a non-ionic or anionic surfactant for said particles.
• Such surfactants may also be present in the aqueous solution or suspension of the organic carboxylic acid or its salt; and in the aqueous solution of the silver salt; may be added via an additional jet during the production process of the suspension of particles containing a substantially light-insensitive silver salt of a organic carboxylic acid; and may be added at the end of the production process.
• a process for producing a photothermographic recording material according to the present invention is also provided, wherein the process further comprises the step of producing particles of the photosensitive silver halide from excess silver ions associated with particles of the substantially light-insensitive silver salt of an organic carboxylic acid.
• the regulated excess of silver ions during the production of the particles may be achieved by maintaining the UAg of the aqueous liquid, defined as the potential difference between a silver electrode (of >99.99% purity) in the liquid and a reference electrode consisting of a Ag/AgCl-electrode in 3M KCl solution at room temperature connected with the liquid via a salt bridge consisting of a 10% KN0 3 salt solution, at 70°C at at least 380mV.
• salts produced during the process and any excess dissolved ions may be removed by on-line or off-line desalting processes such as dialysis or ultrafiltration. Desalting of the suspension may also be achieved after completion of the production process by precipitation of the suspension, followed by decantation, washing and redispersion.
• the suspending medium may be changed from a hydrophilic to a hydrophobic suspending medium.
• a process according to the present invention may be carried out batchwise or in continuous mode in any suitable recipient.
• the photosensitive silver halide used in the present invention may be employed in a range of 0.1 to 35 mol percent of substantially light-insensitive silver salt of an organic carboxylic acid, with the range of 0.5 to 20 mol percent being preferred and the range of 1 to 12 mol percent being particularly preferred.
• the silver halide may be any photosensitive silver halide such as silver bromide, silver iodide, silver chloride, silver bromoiodide, silver chlorobromoiodide, silver chlorobromide etc.
• the silver halide may be in any form which is photosensitive including, but not limited to, cubic, orthorhombic , tabular, tetrahedral, octagonal etc. and may have epitaxial growth of crystals thereon.
• the silver halide used in the present invention may be employed without modification. However, it may be chemically sensitized with a chemical sensitizing agent such as a compound containing sulphur, selenium, tellurium etc., or a compound containing gold, platinum, palladium, iron, ruthenium, rhodium or iridium etc., a reducing agent such as a tin halide etc., or a combination thereof.
• a chemical sensitizing agent such as a compound containing sulphur, selenium, tellurium etc., or a compound containing gold, platinum, palladium, iron, ruthenium, rhodium or iridium etc.
• a reducing agent such as a tin halide etc.
• the silver halide may be added to the photo-addressable thermally developable element in any fashion which places it in catalytic proximity to the substantially light-insensitive silver salt of an organic carboxylic acid.
• Silver halide and the substantially light-insensitive silver salt of an organic carboxylic acid which are separately formed, i.e. ex-situ or "preformed", in a binder can be mixed prior to use to prepare a coating solution, but it is also effective to blend both of them for a long period of time. Furthermore, it is effective to use a process which comprises adding a halogen-containing compound to the silver salt of an organic carboxylic acid to partially convert the substantially light-insensitive silver salt of an organic carboxylic acid to silver halide as disclosed in US-P 3,457,075.
• particles of the photosensitive silver halide are non- aggregating in the photo-addressable thermally developable element and are uniformly distributed over and between particles of the substantially light-insensitive silver salt of an organic carboxylic acid, at least 80% by number of the particles having a diameter, determined by transmission electron microscopy, of ⁇ 40nm.
• a production process for the photothermographic recording material further comprising the step of forming particles of the photosensitive silver halide by reacting an aqueous emulsion of particles of the substantially light-insensitive silver salt of an organic carboxylic acid with at least one onium salt with halide or polyhalide anion(s) .
• particles of the photosensitive silver halide are produced from excess silver ions associated with particles of the substantially light-insensitive silver salt of a organic carboxylic acid produced by simultaneous metered addition of an aqueous solution or suspension of a organic carboxylic acid, or its salt, and an aqueous solution of a silver ⁇ alt to an aqueous liquid.
• Agents used for converting the excess dissolved silver ions into a silver salt may be inorganic halides, such as metallic halides e.g. KBr, KI, CaBr 2 , Cal 2 etc.; or ammonium halides.
• production of the suspension of particles containing a substantially light-insensitive silver salt is immediately followed by the production of silver halide "in-situ" in the same recipient, thereby producing a photosensitive suspension.
• the aqueous emulsion of the silver salt of an organic carboxylic acid optionally including photosensitive silver halide can, according to the present invention, also be produced from particles of the silver salt of an organic carboxylic acid optionally containing photosensitive silver halide by dispersing the particles in water in the presence of non-ionic or anionic surfactants or a mixture of non-ionic and anionic surfactants using any dispersion technique known to one skilled in the art such as ball milling, dispersion in a impingement mill (rotor-stator mixer) , dispersion in a microfluidizer etc.
• a combination of dispersion techniques may also be used, for example using a first technique to produce a predispersion and a second technique to produce a fine dispersion.
• photosensitive silver halide particles produced by reacting an aqueous dispersion of particles of the substantially light-insensitive silver salt of an organic carboxylic acid with at least one onium salt with halide or polyhalide anions may be present.
• the halide or polyhalide onium salts, according to the present invention may be added as solids or solutions or may be formed in the aqueous dispersion of particles of the substantially light-insensitive silver salt by metathesis between a salt with halide or polyhalide anions and onium salts with anions other than halide or polyhalide.
• Preferred oniums according to the present invention are organo- phosphonium, organo-sulphonium and organo-nitrogen onium cations, with heterocyclic nitrogen onium (e.g. pyridinium), quaternary phosphonium and ternary sulphonium cations being preferred.
• Preferred halide anions. according to the present invention are chloride, bromide and iodide.
• Preferred polyhalide anions, according to the present invention consist of chlorine, bromine and iodine atoms .
• Onium cations may be polymeric or non-polymeric.
• Preferred non-polymeric onium salts for partial conversion of particles of substantially light-insensitive silver salt of an organic carboxylic acid into photo-sensitive silver halides according to the present invention are:
• PC01 3- (triphenyl-phosphonium)propionic acid bromide perbromide
• PC02 3- (triphenyl-phosphonium)propionic acid bromide
• PC03 • 3- (triphenyl-phosphonium)propionic acid iodide
• the onium salts are present in quantities of between 0.1 and 35mol % with respect to the quantity of substantially light-insensitive silver salt of an organic carboxylic acid, with quantities between 0.5 and 20mol% being preferred and quantities between 1 and 12mol % being particularly preferred.
• the photo-addressable thermally developable element of the photothermographic recording material further comprises a dye with maximum absorbance in the wavelength range 600 to llOOnm.
• the photo-addressable thermally developable element of the photothermographic recording material may contain a spectral sensitizer, optionally together with a supersensitizer, for the silver halide.
• the silver halide may be spectrally sensitized with various known dyes including cyanine, merocyanine, styryl, hemicyanine, oxonol , hemioxonol and xanthene dyes optionally, particularly in the case of sensitization to infra ⁇ red radiation, in the presence of a so-called supersensitizer.
• Useful cyanine dyes include those having a basic nucleus, such as a thiazoline nucleus, an oxazoline nucleus, a pyrroline nucleus, a pyridine nucleus, an oxazole nucleus, a thiazole nucleus, a selenazole nucleus and an imidazole nucleus.
• a basic nucleus such as a thiazoline nucleus, an oxazoline nucleus, a pyrroline nucleus, a pyridine nucleus, an oxazole nucleus, a thiazole nucleus, a selenazole nucleus and an imidazole nucleus.
• Useful merocyanine dyes which are preferred include those having not only the above described basic nuclei but also acid nuclei, such as a thiohydantoin nucleus, a rhodanine nucleus, an oxazolidinedione nucleus, a thiazolidinedione nucleus, a barbituric acid nucleus, a thiazolinone nucleus, a malononitrile nucleus and a pyrazolone nucleus.
• acid nuclei such as a thiohydantoin nucleus, a rhodanine nucleus, an oxazolidinedione nucleus, a thiazolidinedione nucleus, a barbituric acid nucleus, a thiazolinone nucleus, a malononitrile nucleus and a pyrazolone nucleus.
• imino groups or carboxyl groups are particularly effective.
• Suitable sensitizers of silver halide to infra-red radiation include those disclosed in the EP-A's 465 078, 559 101. 616 014 and 635 756. the JN's 03-080251. 03-163440, 05-019432, 05-072662 and 06-003763 and the US-P's 4,515.888, 4.639,414, 4,713,316, 5,258,282 and 5,441,866.
• Suitable supersensitizers for use with infra-red spectral sensitizers are disclosed in EP-A's 559 228 and 587 338 and in the US-P's 3.877.943 and 4.873.184.
• binders or mixtures thereof may be used in conjunction with waxes or "heat solvents” also called “thermal solvents” or “thermosolvents” improving the reaction speed of the redox-reaction at elevated temperature.
• heat solvent in this invention is meant a non ⁇ hydrolyzable organic material which is in a solid state in the recording layer at temperatures below 50°C, but becomes a plasticizer for the recording layer where thermally heated and/or a liquid solvent for at least one of the redox-reactants, e.g. the reducing agent for the substantially light-insensitive silver salt of an organic carboxylic acid, at a temperature above 60°C.
• redox-reactants e.g. the reducing agent for the substantially light-insensitive silver salt of an organic carboxylic acid
• Suitable heat solvents are compounds such as urea, methyl sulfonamide and ethylene carbonate as described in US-P 3,667,959; compounds such as tetrahydro-thiophene-1 , 1-dioxide, methyl anisate and 1 , 10-decanediol as described in Research Disclosure 15027 published in December 1976; and those described in US-P 3.438,776, US-P 4,740,446. US-P 5,368,979. EP-A 0 119 615, EP-A 122 512 and DE-A 3 339 810.
• photothermographic materials according to the present invention may contain one or more toning agents.
• the toning agents should be in thermal working relationship with the substantially light- insensitive silver salt of an organic carboxylic acids and reducing agents during thermal processing. Any known toning agent from thermography or photothermography may be used.
• Suitable toning agents are succinimide and the phthalimides and phthalazinones within the scope of the general formulae described in US-P 4,082,901 and the toning agents described in US-P 3,074,809, US-P 3,446,648 and US-P 3,844,797.
• Particularly useful toning agents are the heterocyclic toner compounds of the benzoxazine dione or naphthoxazine dione type within the scope of following general formula are described in GB-P 1,439,478 and US-P 3.951,660:
• X represents 0 or N-alkyl; each of R 1 , R 2 , R 3 and R 4 (same or different) represents hydrogen, alkyl, e.g. C1-C20 alkyl, preferably C1-C4 alkyl, cycloalkyl, e.g.
• R 1 and R 2 or R 2 and R 3 represent the ring members required to complete a fused aromatic ring, preferably a benzene ring, or R 3 and R 11 represent the ring members required to complete a fused aromatic aromatic or cyclohexane ring.
• a toner compound, according to the above general formula, particularly suited for use in combination with polyhydroxy benzene reducing agents is benzo [e] [1 ,3] oxazine-2 ,4-dione.
• stabilizers and antifoggants may be incorporated into the photothermographic materials of the present invention.
• suitable stabilizers and antifoggants and their precursors include the thiazolium salts described in US-P 2,131,038 and 2,694,716; the azaindenes described in US-P 2,886,437 and 2,444,605; the urazoles described in US-P 3.287,135; the sulfocatechols 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; the palladium, platinum and gold salts described in US-P 2,566,263 and 2,597,915; the tetrazolyl-thio-compounds described in US-P 3,700,457; the mesoionic 1 ,2 ,4-tri
• Non-ionic, cationic or anionic surfactants may be used, according to the present invention, to produce dispersions of particles of the substantially light-insensitive silver salt of an organic carboxylic acid in aqueous media and to disperse water- dispersible binders, such as polymer latexes, in aqueous media.
• a mixture of non-ionic and anionic surfactacts, of non-ionic and cationic surfactants, of cationic and anionic surfactants or of non ⁇ ionic, cationic and anionic surfactants may also be used, according to the present invention.
• the surfactant is an anionic surfactant.
• the anionic surfactant is a sulfonate e.g. alkyl, aryl, alkaryl or aralkyl sulfonate, with alkyl and alkaryl sulfonates being particularly preferred e.g.:
• MERSOLATTM H a sodium salt of an alkyl sulfonate from BAYER ULTRAVONTM W, a sodium salt of an aryl sulfonate from CIBA-GEIGY
• the ionic surfactant is a non-ionic surfactant for example alkyl, aryl, alkaryl or aralkyl polyethoxy ethanols.
• Preferred non-ionic surfactants, according to the present invention are alkoxy- polyethoxy ethanols and alkaryloxy-polyethoxy ethanols.
• the photothermographic material may contain other additives such as free organic carboxylic acids, surface-active agents, antistatic agents, e.g. non-ionic antistatic agents including a fluorocarbon group as e.g. in
• the photothermographic recording material of the present invention may contain antihalation or acutance dyes which absorb light which has passed through the photosensitive layer, thereby preventing its reflection. Such dyes may be incorporated into the photo-addressable thermally developable element or in any other layer comprising the photothermographic recording material of the present invention.
• the anti-halation dye may also be bleached either thermally during the thermal development process, as disclosed in the US-P's 4,033,948, 4,088,497, 4,153,463, 4,196,002, 4,201.590, 4,271,263, 4,283,487, 4.308,379, 4,316.984, 4,336,323, 4.373,020, 4.548.896, 4,594.312, 4,977.070.
• the anti-halation layer may be contained in a layer which can be removed subsequent to the exposure process, as disclosed in US-P 4.477,562 and EP-A 491 457. Suitable anti-halation dyes for use with infra-red light are described in the EP-A's 377 961 and 652 473, the EP-B's 101 646 and 102 781 and the US-P's 4.581,325 and 5.380,635.
• the support for the photothermographic recording material according to the present invention may be transparent, translucent or opaque, e.g. having a white light reflecting aspect and is preferably a thin flexible carrier made e.g. from paper, polyethylene coated paper or transparent resin film, e.g. made of a cellulose ester, e.g. cellulose triacetate, corona and flame treated polypropylene, polystyrene, polymethacrylic acid ester, polycarbonate or polyester, e.g. polyethylene terephthalate or polyethylene naphthalate as disclosed in GB 1,293,676, GB 1,441.304 and GB 1,454,956.
• a paper base substrate is present which may contain white reflecting pigments, optionally also applied in an interlayer between the recording material and the paper base substrate.
• the support may be in sheet, ribbon or web form and subbed if needs be to improve the adherence to the thereon coated heat-sensitive recording layer.
• Suitable subbing layers for improving the adherence of the thermosensitive element and the antistatic layer outermost backing layer of the present invention for polyethylene terephthalate supports are described e.g. in GB-P 1,234,755, US-P 3.397.988; 3.649.336; 4,123,278 and US-P 4,478,907 which relates to subbing layers applied from aqueous dispersion of sulfonated copolyesters, and further the subbing layers described in Research Disclosure published in Product Licensing Index, July 1967, p. 6.
• Suitable pretreatments of hydrophobic resin supports are, for example, treatment with a corona discharge and/or attack by solvent(s), thereby providing a micro-roughening.
• the support may be made of an opacified resin composition, e.g. polyethylene terephthalate opacified by means of pigments and/or micro-voids, and/or may be coated with an opaque pigment-binder layer, and may be called synthetic paper, or paperlike film.
• an opacified resin composition e.g. polyethylene terephthalate opacified by means of pigments and/or micro-voids
• an opaque pigment-binder layer e.g. polyethylene terephthalate opacified by means of pigments and/or micro-voids
• an opaque pigment-binder layer e.g. polyethylene terephthalate opacified by means of pigments and/or micro-voids
• an opaque pigment-binder layer e.g. polyethylene terephthalate opacified by means of pigments and/or micro-voids
• an opaque pigment-binder layer e.g. polyethylene terephthalate opacified by means of pigments and/or micro-void
• the photo-addressable thermally developable element is provided with a protective layer to avoid local deformation of the photo-addressable thermally developable element, to improve its resistance against abrasion and to prevent its direct contact with components of the apparatus used for thermal development.
• This protective layer may have the same composition as an anti- sticking coating or slipping layer which is applied in thermal dye transfer materials at the rear side of the dye donor material or protective layers used in materials for direct thermal recording.
• the protective layer preferably comprises a binder, which may be solvent soluble (hydrophobic), solvent dispersible, water soluble (hydrophilic) or water dispersible.
• a binder which may be solvent soluble (hydrophobic), solvent dispersible, water soluble (hydrophilic) or water dispersible.
• hydrophobic binders polycarbonates as described in EP-A 614 769 are particularly preferred.
• Suitable hydrophilic binders are, for example, gelatin, polyvinylalcohol, cellulose derivatives or other polysaccharides, hydroxyethylcellulose, hydroxypropylcellulose etc., with hardenable binders being preferred and polyvinylalcohol being particularly preferred.
• a protective layer according to the present invention may be crosslinked.
• Crosslinking can be achieved by using crosslinking agents such as described in WO 95/12495 for protective layers, e.g. tetra-alkoxysilanes, polyisocyanates, zirconates, titanates, melamine resins etc., with tetraalkoxysilanes such as tetramethylorthosilicate and tetraethylorthosilicate being preferred.
• a protective layer according to the present invention may comprise in addition at least one solid lubricant having a melting point below 150°C and at least one liquid lubricant in a binder, wherein at least one of the lubricants is a phosphoric acid derivative, further dissolved lubricating material and/or particulate material, e.g. talc particles, optionally protruding from the outermost layer.
• suitable lubricating materials are surface active agents, liquid lubricants, solid lubricants which do not melt during thermal development of the recording material, solid lubricants which melt (thermomeltable) during thermal development of the recording material or mixtures thereof.
• the lubricant may be applied with or without a polymeric binder.
• the surface active agents may be any agents known in the art such as carboxylates, sulfonates, aliphatic amine salts, aliphatic quaternary ammonium salts, polyoxyethylene alkyl ethers, polyethylene glycol organic carboxylic acid esters, fluoroalkyl C -C 60 aliphatic acids.
• liquid lubricants include silicone oils, synthetic oils, saturated hydrocarbons and glycols.
• solid lubricants include various higher alcohols such as stearyl alcohol and organic carboxylic acids. Suitable slipping layer compositions are described in e.g. EP 138483, EP 227090, US-P 4,567,113, 4,572,860 and 4,717,711 and in EP-A 311841.
• a suitable slipping layer being a layer comprising as binder a styrene-acrylonitrile copolymer or a styrene-acrylonitrile-butadiene copolymer or a mixture hereof and as lubricant in an amount of 0.1 to 10 % by weight of the binder (mixture) a polysiloxane-polyether copolymer or polytetrafluoroethylene or a mixture hereof.
• Such protective layers may also comprise particulate material, e.g. talc particles, optionally protruding from the protective outermost layer as described in WO 94/11198.
• Other additives can also be incorporated in the protective layer e.g. colloidal particles such as colloidal silica.
• an antistatic layer is applied to the outermost layer on the side of the support not coated with the photo-addressable thermally developable element.
• Suitable antistatic layers therefor are described in EP-A's 444 326, 534 006 and 644 456, US-P's 5.364,752 and 5,472,832 and DOS 4125758.
• any layer of the photothermographic materials of the present invention may proceed by any coating technique e.g. such as 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, U.S.A.
• Photothermographic materials may be exposed with radiation of wavelength between an X- ray wavelength and a 5 microns wavelength with the image either being obtained by pixel-wise exposure with a finely focussed light source, such as a CRT light source; a UV, visible or IR wavelength laser, such as a He/Ne-laser or an IR-laser diode, e.g. emitting at 780nm, 830nm or 850nm; or a light emitting diode, for example one emitting at 659nm; or by direct exposure to the object itself or an image therefrom with appropriate illumination e.g. with UV, visible or IR light.
• a finely focussed light source such as a CRT light source
• a UV, visible or IR wavelength laser such as a He/Ne-laser or an IR-laser diode, e.g. emitting at 780nm, 830nm or 850nm
• a light emitting diode for
• any sort of heat source can be used that enables the recording materials to be uniformly heated to the development temperature in a time acceptable for the application concerned e.g. contact heating, radiative heating, microwave heating etc.
• the photothermographic recording materials of the present invention can be used for both the production of transparencies and reflection type prints.
• the support will be transparent or opaque, e.g. having a white light reflecting aspect.
• a paper base substrate is present which may contain white reflecting pigments, optionally also applied in an interlayer between the recording material and the paper base substrate. Should a transparent base be used, the base may be colourless or coloured, e.g. has a blue colour.
• REDU C16 potassium hydroquinone monosulfonate reducing agents from the detailed description of US-P 4,504,575: REDU C06 and C16;
• REDU C19 ammonium 3 ,4-dihydroxybenzenesulfonate
• REDU C20 sodium 5 ,6-dihydroxy-benzene-l ,3-disulfonate
• Binders used in the comparative and invention examples are identical to Binders used in the comparative and invention examples:
• GELATIN 01 type K7598 from AGFA GELATINFABRIK vorm. KOEPFF &
• BINDER 01 copolymer consisting of 45% by weight of methylmethacrylate, 45% by weight of butadiene and 10% by weight of itaconic acid.
• Silver behenate was prepared by dissolving 602.7g (1.77moles) of behenic acid in 6.027L of 2-propanol at 65°C, converting the behenic acid to sodium behenate by adding 7.078L of 0.25M aqueous sodium hydroxide to the stirred behenic acid solution and finally adding 4.424L of 0.4M aqueous silver nitrate the silver behenate precipitating out. This was filtered off and then washed with a mixture of 10% by volume of 2-propanol and 90% by volume of deionized water to remove residual sodium nitrate.
• the silver behenate was dispersed in deionized water with the anionic dispersion agents UltravonTM W and MersolatTM H producing, after rapid mixing to produce a predispersion and homogenization with a microfluidizer, a finely divided and stable dispersion containing 20% by weight of silver behenate, 2.1% by weight of UltravonTM W and 0.203% by weight of MersolatTM H.
• the pH of the resulting dispersion was adjusted to about 6.5.
• a roll of subbed lOO ⁇ m thick polyethylene terephthalate support was doctor blade-coated with the resulting dispersion to a wet thickness of 53 ⁇ m and then dried in a hot air drying cupboard.
• the coated roll was cut into sheets which were then individually doctor blade-coated with solutions of the different reducing agents given below in table 1 for the materials of comparative examples 1 to 15 and invention example 1 in deionized water or methanol with quantities of solution corresponding to quantities of reducing agent corresponding to the molar ratio of silver behenate to reducing agent given in table 1.
• the resulting photothermographic material was allowed to dry on the coating bed for several minutes at 40°C and then was dried for 1 hour in a hot air oven at 50°C.
• the photothermographic material was then exposed to ultra-violet light through a test original in contact with the material in an Agfa-GevaertTM DL 2000 exposure apparatus.
• Thermal development was carried out in pressure contact with a metal block whose temperature could be varied between 95 and 120°C.
• the thermal development conditions were adjusted to give the best image and the temperatures and heating times used are given in table 1.
• the quality of the image obtained was assessed qualitatively and awarded a numerical score between 0 and 5 where these values correspond to:
• the numerical scores awarded to the materials of comparative examples 1 to 15 and invention example 1 are given in table 1.
• the maximum and minimum optical density values, D max and D ffiin were determined using a MacBethTM TR924 densitometer with a visible filter.
• invention examples 2 to 4 and comparative example 16 were produced as described for comparative examples 1 to 15 and invention example 1 except that other reducing agents were used as given in tables 2 and 3 respectively.
• invention examples 5 to 22 and comparative examples 17 to 24 were produced as described for comparative examples 1 to 15 and invention example 1 except that other reducing agents were used as given in tables 4 and 5 for the comparative examples and invention examples respectively.
• a sodium behenate solution was prepared by first dissolving 34kg of behenic acid in 340L of isopropanol at 65°C and then adding with stirring a 0.25N solution of sodium hydroxide until a solution pH of 8.7 was obtained. This required about 400L of 0.25N NaOH. The concentration of the resulting solution was then adjusted to a sodium behenate concentration of 8.9% by weight and a concentration of isopropanol in the solvent mixture of 16.7% by volume, by a combination of evaporation and dilution.
• the silver behenate synthesis was carried out at a constant UAg of 400mV as follows: to a stirred solution of 30g of GELATIN 01 in 750mL of distilled water at 72°C in a double walled reactor, several drops of a 2.94M aqueous solution of silver nitrate were added to adjust the UAg at the start of the reaction to 400mV and then 374mL of the sodium behenate solution, whose preparation is described above, at a temperature of 78°C was metered into the reactor at a rate of 46.6mL/min and simultaneously a 2.94M aqueous solution of silver nitrate was metered into the reactor, its addition rate being controlled by the quantity of the silver nitrate solution necessary to maintain a UAg of 400 ⁇ 5mV in the dispersing medium in the reactor. Both the sodium behenate and silver nitrate solutions were added to the dispersing medium via small diameter tubes positioned just under the surface of the dispersing medium.
• Silver behenate was prepared by dissolving 34g (0.1 moles) of behenic acid in 340mL of 2-propanol at 65°C, converting the behenic acid to sodium behenate by adding 400mL of 0.25M aqueous sodium hydroxide to the stirred behenic acid solution and finally adding 250mL of 0.4M aqueous silver nitrate the silver behenate precipitating out. This was filtered off and then washed with a mixture of 10% by volume of 2-propanol and 90% by volume of deionized water to remove residual sodium nitrate.
• the silver behenate was dispersed in deionized water with the anionic dispersion agents UltravonTM W and MersolatTM H an aqueous solution producing after rapid mixing to produce a predispersion and homogenization with a microfluidizer a finely divided and stable dispersion containing 20% by weight of silver behenate, 2.1% by weight of UltravonTM W and 0.203% by weight of MersolatTM H.
• the pH of the resulting dispersion was adjusted to about 6.5.
• the large rod-shaped particles are silver behenate.
• the very small black particles. ⁇ 40nm in diameter, uniformly distributed over these silver behenate particles and also uniformly distributed between these particles are silver bromide particles.
• a subbed polyethylene terephthalate support having a thickness of lOO ⁇ m was doctor blade-coated with the silver behenate/silver bromide dispersion at a blade setting of 60 ⁇ m. After drying for several minutes at 40°C on the coating bed, the emulsion layer was then doctor blade-coated with a 2.44% by weight aqueous solution of 3- (3 ,4-dihydroxyphenyl)propionic acid at a blade setting of 30 ⁇ m. The resulting thermographic material was first allowed to dry on the coating bed for several minutes at 40°C and then was dried for 1 hour in a hot air drying cupboard at 50°C.

Landscapes

• Chemical & Material Sciences (AREA)
• Engineering & Computer Science (AREA)
• Materials Engineering (AREA)
• Physics & Mathematics (AREA)
• General Physics & Mathematics (AREA)
• Non-Silver Salt Photosensitive Materials And Non-Silver Salt Photography (AREA)
• Colloid Chemistry (AREA)
• Heat Sensitive Colour Forming Recording (AREA)
• Emulsifying, Dispersing, Foam-Producing Or Wetting Agents (AREA)

Priority Applications (4)

Applications Claiming Priority (2)

Related Child Applications (1)

Publications (2)

Family

ID=8220499

Family Applications (3)

Family Applications Before (1)

Family Applications After (1)

Country Status (5)

Cited By (3)

Families Citing this family (50)

Family Cites Families (30)

• 1996
  • 1996-06-13 EP EP96921993A patent/EP0839337B1/en not_active Expired - Lifetime
  • 1996-06-13 WO PCT/EP1996/002582 patent/WO1997004356A1/en not_active Ceased
  • 1996-06-13 DE DE69621337T patent/DE69621337T2/de not_active Expired - Fee Related
  • 1996-06-13 EP EP96922811A patent/EP0839338B1/en not_active Expired - Lifetime
  • 1996-06-13 JP JP50620797A patent/JP3794706B2/ja not_active Expired - Fee Related
  • 1996-06-13 DE DE69611171T patent/DE69611171T2/de not_active Expired - Fee Related
  • 1996-06-13 EP EP96921994A patent/EP0840906B1/en not_active Expired - Lifetime
  • 1996-06-13 JP JP50620597A patent/JP3714958B2/ja not_active Expired - Fee Related
  • 1996-06-13 WO PCT/EP1996/002583 patent/WO1997004357A2/en not_active Ceased
  • 1996-06-13 DE DE69616337T patent/DE69616337T2/de not_active Expired - Fee Related
  • 1996-06-13 WO PCT/EP1996/002581 patent/WO1997004355A1/en not_active Ceased
  • 1996-06-13 JP JP50620697A patent/JP3715990B2/ja not_active Expired - Fee Related
  • 1996-07-11 DE DE69630837T patent/DE69630837T2/de not_active Expired - Fee Related
  • 1996-07-11 EP EP96201955A patent/EP0754969B1/en not_active Expired - Lifetime
  • 1996-07-15 JP JP8205343A patent/JP3069294B2/ja not_active Expired - Fee Related
• 1998
  • 1998-01-20 US US09/009,764 patent/US6143481A/en not_active Expired - Fee Related
  • 1998-01-20 US US09/009,717 patent/US6280923B1/en not_active Expired - Fee Related
  • 1998-01-20 US US09/009,721 patent/US6187528B1/en not_active Expired - Fee Related

Also Published As

Similar Documents

Legal Events