EP0754969A2
Expired / Lapsed
EP
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Process for producing an aqueous suspension of particles containing a substantially light-insensitive silver salt of an organic carboxylic acid for production of (photo)thermographic materials
Assignee: Agfa Gevaert NV
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Filing: 1996-07-11
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Granted: —
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Expires: 2016-07-11
Abstract
Abstract A process for producing a suspension of particles containing a substantially light-insensitive organic silver salt of an organic carboxylic acid, comprising 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. wherein 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 is regulated by the concentration of silver ions or the concentration of anions of the silver salt in the aqueous liquid ; for use in the production of (photo)thermographic materials.
Inventors
- 👤 Yvan Gilliams
- 👤 Herman Uytterhoeven
Bibliographic Details
Application Number
—
Jurisdiction
EP
Data Source
google_patents
Last Synchronized
2026-11-02 03:54
CPC Classifications
G; G03; G03C; G03C1/00; G03C1/494; G03C1/498; G03C1/49809; G03C1/005; G03C1/035; G03C1/49836; G03C1/49863; G03C1/4989; G03C1/015; G03C2001/0156; G03C2001/03594; G03C2200/00; G03C2200/36; G03C2200/43
Claims Analysis
Total Claims: 18
Claim 1
Independent Claim
96 words
A process for producing a suspension of particles containing a substantially light-insensitive silver salt of an organic carboxylic acid, comprising 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, wherein said metered addition of said aqueous solution or suspension of said organic carboxylic acid or its salt; and/or said aqueous solution of said silver salt is regulated by the concentration of silver ions or the concentration of anions of said silver salt in said aqueous liquid.
Claim 2
Dependent Claim
28 words
A process according to claim 1, further comprising the step of removing soluble salts produced during said process and any excess dissolved ions by on-line or off-line desalting.
Claim 3
Dependent Claim
19 words
A process according to claim 1 or 2, wherein said aqueous liquid contains a dispersing agent for said particles.
Claim 4
Dependent Claim
31 words
A process according to claim 3, wherein said dispersing agent is selected from the group consisting of: a natural polymeric substance, a synthetic polymeric substance and a finely divided inorganic powder.
Claim 5
Dependent Claim
17 words
A process according to claim 4, wherein said natural polymeric substance is gelatin or a modified gelatin.
Claim 6
Dependent Claim
55 words
A process according to claim 1, wherein said metered addition of said aqueous solution or suspension of said organic carboxylic acid or its salt: and/or said silver salt aqueous solution to said aqueous liquid is regulated such that an excess of silver ions is present in said aqueous liquid during said production of said particles.
Claim 7
Dependent Claim
83 words
A process according to claim 6, wherein said regulated excess of silver ions during said production of said particles is achieved by maintaining the UAg of said aqueous liquid, defined as the potential difference between a silver electrode of ≥99.99% purity in said aqueous liquid and a reference electrode consisting of a Ag/AgC1-electrode in 3M KCl solution at room temperature connected with said aqueous liquid via a salt bridge consisting of a 10% KNO 3 salt solution, at 70°C at at least 380mV.
Claim 8
Dependent Claim
25 words
A process according to claim 7, wherein the UAg of said aqueous liquid is such that 80% of said particles have no preferred growth direction.
Claim 9
Dependent Claim
24 words
A process according to claim 7, wherein the UAg of said aqueous is such that 90% of said particles have a diameter ≤ 60nm.
Claim 10
Dependent Claim
33 words
A process according to any of the preceding claims, wherein said organic carboxylic acid is a fatty acid and said salt of an organic carboxylic acid is a salt of a fatty acid.
Claim 11
Dependent Claim
19 words
A process according to claim 10, wherein said salt of a fatty acid is a salt of behenic acid.
Claim 12
Dependent Claim
34 words
A process according to any of the preceding claims, wherein after completion of said production of said aqueous suspension of said particles, excess dissolved silver ions are converted into at least one silver salt.
Claim 13
Dependent Claim
12 words
A process according to claim 12, wherein said silver salt is photosensitive.
Claim 14
Dependent Claim
20 words
A process according to any of the preceding claims, wherein said particles are produced in the presence of silver halide.
Claim 15
Dependent Claim
34 words
A thermographic recording material comprising particles produced according to any of claims 1 to 12, an organic reducing agent for said particles in thermal working relationship with said particles and a film-forming polymeric binder.
Claim 16
Dependent Claim
68 words
A photothermographic recording material comprising particles produced according to any of claims 1 to 12, an organic reducing agent for said particles in thermal working relationship with said particles, a film-forming polymeric binder and a photosensitive agent, or a component capable of forming a photosensitive agent with said particles, capable after exposure of catalyzing the thermal reduction of said particles to metallic silver with said organic reducing agent.
Claim 17
Dependent Claim
15 words
A photothermographic recording material according to claim 16, wherein said photosensitive agent is silver halide.
Claim 18
Dependent Claim
25 words
A photothermographic material according to claim 16, wherein said component capable of forming a photosensitive agent with said particles has a negatively ionizable halogen atom.
References Cited (Backward Citations)
No citation records indexed.
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