# US 7,410,752 B2 · Method of producing organic silver salt dispersion, and photothermographic material > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 7,410,752 B2 - Document ID: US7410752B2 - Status: Granted - Kind: B2 - Application number: 11/230,499 - Filed: 2005-09-21 - Published: 2006-03-30 - Granted: 2008-08-12 - Earliest claimed: 2004-09-27 - Assignees: FUJIFILM Corporation - Inventors: Itsuo Fujiwara - Web page: https://patentgrep.com/patent/US7410752B2 ## CPC - G03C 1/49809: {Organic silver compounds} - G03C 1/04: with macromolecular additives; with layer-forming substances - G03C 1/49845: {Active additives, e.g. toners, stabilisers, sensitisers} - G03C 1/49863: {Inert additives, e.g. surfactants, binders} - G03C: PHOTOSENSITIVE MATERIALS FOR PHOTOGRAPHIC PURPOSES (for photomechanical purposes G03F); PHOTOGRAPHIC PROCESSES, e.g. CINE, X-RAY, COLOUR, STEREO-PHOTOGRAPHIC PROCESSES; AUXILIARY PROCESSES IN PHOTOGRAPHY (photographic processes characterised by the use or manipulation of apparatus classifiable per se in subclass G03B, see G03B; photomechanical production of textured or patterned surfaces G03F; electrophotography, magnetography G03G) ## Abstract A method of producing an organic silver salt dispersion, the method comprising: mixing a first aqueous solution including a water-soluble silver ion supplier and a second aqueous solution including an alkali metal salt of an organic acid to form an organic silver salt dispersion; wherein, the mixing is conducted in the presence of at least one compound selected from polyacrylamide and derivatives of polyacrylamide, and at least 10 mass % (in terms of silver quantity) of the organic silver salt in the organic silver salt dispersion is formed by simultaneous addition of the first aqueous solution and the second aqueous solution to an aqueous medium followed by mixing. ## Claims ### Claim 1 A method of producing an organic silver salt dispersion, the method comprising: mixing a first aqueous solution including a water-soluble silver ion supplier and a second aqueous solution including an alkali metal salt of an organic acid to form an organic silver salt dispersion; wherein, the second aqueous solution further includes at least one compound selected from polyacrylamide and derivatives of polyacrylamide, and at least 10 mass %, in terms of silver quantity, of the organic silver salt in the organic silver salt dispersion is formed by simultaneous addition of the first aqueous solution and the second aqueous solution to an aqueous medium followed by mixing. ### Claim 2 (depends on 1) The method of producing an organic silver salt dispersion according to claim 1, the method further comprising adding at least one compound selected from polyacrylamide and derivatives of polyacrylamide to the aqueous medium after the simultaneous addition of the first and second aqueous solutions. ### Claim 3 (depends on 1) The method of producing an organic silver salt dispersion according to claim 1, wherein the compound selected from polyacrylamide and derivatives of polyacrylamide is a compound represented by formula (W1) or (W2): wherein in formulae (W1) and (W2), R represents a hydrophobic group, R1 and R2 each independently represent a hydrogen atom or a hydrophobic group, at least one of R1 and R2 is a hydrophobic group, L represents a divalent connecting group, T represents an oligomer moiety, and the hydrophobic group is a saturated or unsaturated alkyl group, an arylalkyl group, or an alkylaryl group. ### Claim 4 (depends on 2) The method of producing an organic silver salt dispersion according to claim 2, wherein the compound selected from polyacrylamide and derivatives of polyacrylamide added after the simultaneous addition is a compound represented by formula (W1) or (W2): wherein in formulae (W1) and (W2), R represents a hydrophobic group, R1 and R2 each independently represent a hydrogen atom or a hydrophobic group, at least one of R1 and R2 is a hydrophobic group, L represents a divalent connecting group, T represents an oligomer moiety, and the hydrophobic group is a saturated or unsaturated alkyl group, an arylalkyl group, or an alkylaryl group. ### Claim 5 (depends on 1) The method of producing an organic silver salt dispersion according to claim 1, wherein particles of the organic silver salt are nano particles. ### Claim 6 (depends on 5) The method of producing an organic silver salt dispersion according to claim 5, wherein an average particle size of the nano particles is 5 nm to 400 nm. ### Claim 7 (depends on 1) The method of producing an organic silver salt dispersion according to claim 1, wherein a standard deviation of a particle size distribution of the organic silver salt particles is 10% to 30%. ### Claim 8 (depends on 1) The method of producing an organic silver salt dispersion according to claim 1, the method further comprising desalinating the organic silver salt dispersion by an ultrafiltration method or by an electrodialysis method after formation of particles of the organic silver salt. ### Claim 9 (depends on 1) The method of producing an organic silver salt dispersion according to claim 1, wherein at least 25 mass % of silver in the first aqueous solution and at least 25 mass % of the organic acid in the second aqueous solution are added to the aqueous medium during a period in which the first and second aqueous solutions are simultaneously added to the aqueous medium. ### Claim 10 (depends on 1) A photothermographic material comprising a support and an image-forming layer provided on at least one side of the support, wherein the image-forming layer includes a photosensitive silver halide, a reducing agent, a binder, and the non-photosensitive organic silver salt produced by the method of claim 1. ### Claim 11 (depends on 10) The photothermographic material according to claim 10, wherein the photothermographic material further include a compound represented by formula (I) or (II): wherein in formula (I), Q represents an atomic group required for forming a 5- or 6-membered imide ring; wherein in formula (II), R5 represents a hydrogen atom, an alkyl group, a cycloalkyl group, an alkoxy group, an alkylthio group, an arylthio group, a hydroxy group, a halogen atom, or N(R8R9); R8 and R9 each independently represent a hydrogen atom, an alkyl group, an aryl group, a cycloalkyl group, an alkenyl group, or a heterocyclyl group; r represents 0, 1 or 2; R8 and R9 may be bonded to each other to form a substituted or unsubstituted 5- to 7-membered heterocyclic ring; when there are two R5s, they may be the same as each other or different from each other, and they may be bonded to each other to form an aromatic, heteroaromatic, alicyclic, or heterocyclic condensed ring; X represents O, S, Se, or N(R6); and R6 represents a hydrogen atom, an alkyl group, an aryl group, a cycloalkyl group, an alkenyl group, or a heterocyclyl group. ### Claim 12 (depends on 10) The photothermographic material according to claim 10, wherein at least 30 mass % of the binder of the image-forming layer is a hydrophilic binder. ### Claim 13 (depends on 12) The photothermographic material according to claim 12, wherein the hydrophilic binder is gelatin or a derivative of gelatin. ### Claim 14 (depends on 12) The photothermographic material according to claim 12, wherein the photothermographic material further comprises a non-photosensitive layer and at least 50 mass % of the binder of the non-photosensitive layer is a hydrophilic binder. ### Claim 15 (depends on 14) The photothermographic material according to claim 14, wherein the hydrophilic binder in the non-photosensitive layer is gelatin or a derivative of gelatin. ### Claim 16 (depends on 12) The photothermographic material according to claim 12, wherein in the image-forming layer, the ratio of the non-photosensitive organic silver salt to the hydrophilic binder is in a range of 1.0 to 2.5.