# US 4,395,484 A · Roomlight-stable ultraviolet-response photothermographic imaging material > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 4,395,484 A - Document ID: US4395484A - Status: Granted - Kind: A - Application number: 06/392,324 - Filed: 1982-06-25 - Granted: 1983-07-26 - Earliest claimed: 1982-06-25 - Assignees: Minnesota Mining and Manufacturing Company - Inventors: Greg J. McCarney - Web page: https://patentgrep.com/patent/US4395484A ## CPC - G03C 1/49872: {Aspects relating to non-photosensitive layers, e.g. intermediate protective layers} - 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 UV sensitive dry silver photothermographic construction for graphic arts use can be freely handled for one to two minutes under cool white fluorescent lighting or incandescent lighting. The construction comprises in sequence: a. a substrate, b. a continuous layer of a dry silver dispersion coating containing an organic silver full soap/half soap blend, a reducing agent, halide ion, and a binder resin, and c. a continuous protective topcoat layer comprising a cellulose acetate resin admixed with an effective amount of a development accelerator, said construction further comprising (1) halide ion in said silver dispersion coating or in said topcoat layer, said halide ion being at least 96 mole percent chloride ion, said halide ion when present in said dispersion coating being admixed in said dispersion subsequent to the admixing of at least a portion of said binder resin with said organic silver soap blend, and (2) an antihalation agent in any of the aforementioned layers or in a separate layer. ## Claims ### Claim 1 A thermophotographic layered construction comprising: a. a transparent or opaque substrate b. coated upon one surface of said substrate, a continuous layer of a dry silver dispersion coating, said coating comprisng: (1) a blend of organic silver full soap and half soap to provide in said layer a weight ratio of total silver in the coating to silver soap in the range of 1:7 to 1:4.2, (2) a polyvinyl acetal resin, said resin to silver soap weight ratio being in the range of 0.6:1 to 2:1, and c. a protective/reaction topcoat layer comprising a cellulose acetate resin admixed with an effective amount of a development accelerator, and construction further comprising d. 0.5 to 20 mole percent of halide ion compared to silver in said silver coating layer or said topcoat layer, at least 96 mole percent of said halide ion being chloride ion, and e. an effective amount of at least one antihalation agent incorporated in any of layers, a., b., c., or d., or in a separate layer between said substrate and said silver coating layer, said construction being intrinsically ultraviolet light-responsive and roomlight stable for at least one minute, and capable of forming graphic arts images having a contrast of at least 2.5. ### Claim 2 (depends on 1) The construction of claim 1 wherein said halide ion to silver ratio is 1.0 to 5.0 mole percent. ### Claim 3 (depends on 1) The construction of claim 1 wherein said total silver to silver soap weight ratio in said silver coating is in the range of 1:6 to 1:4.6. ### Claim 4 (depends on 1) The construction of claim 1 wherein said resin to silver soap weight ratio is in the range of 1:1 to 1.7:1. ### Claim 5 (depends on 1) The construction of claim 1 wherein said development accelerator is selected from (a) phthalazinone and (b) phthalizine and 4-methyl phthalic acid. ### Claim 6 (depends on 1) The construction of claim 1 wherein said substrate is opaque and said at least one antihalation agent is titanium dioxide. ### Claim 7 (depends on 1) The construction of claim 1 wherein said substrate is selected from glass, transparent films, opaque films, paper, fabric, and metall foils. ### Claim 8 A method for preparing a roomlight handleable photothermographic dry silver sheet material which comprises a dry silver dispersion coated on a substrate, halide ion being present in said silver dispersion or in a separate topcoat layer, said sheet material being capable of forming graphic arts images having a contrast of at least 2.5, said method comprisng the steps of: a. admixing, to prepare said dry silver dispersion coating layer, (1) at least 5 weight percent of the total weight of a polyvinyl acetal resin, and (2) a blend of organic silver full soap and half soap to provide in said layer a total silver to silver soap weight ratio in the range of 1:7 to 1:4.2, said total resin to silver soap weight ratio being in the range of 0.6:1 to 2:1, b. adding subsequently and further admixing, when said halide ion is to be present in said silver dispersion, 0.5 to 20 mole percent of halide ion compared to silver in said silver dispersion coating layer, at least 96 mole percent of said halide ion being chloride ion, or providing said halide ion in said separate topcoat layer, c. coating said dispersion on said substrate, and d. incorporating an effective amount of at least one antihalation agent in at least one of said silver dispersion layer, said substrate, said topcoat layer, or in a separate layer between said substrate and said silver dispersion layer.