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US4161408A
Expired / Lapsed
US
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Method for the preparation of a photothermographic system
Assignee: 3M Co
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Filing: 1977-06-06
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Granted: 1979-07-17
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Expires: 1997-06-06
Abstract
Abstract A process of forming photothermographic emulsions which comprises adding silver halide with agitation to a dispersion of melted long chain fatty acid in water in the absence of alkali and ammonia salts of said acid, then converting the acid to an ammonia salt or alkali metal salt, then cooling the dispersion, and thereafter converting the alkali metal salt or ammonia salt to a silver salt of the acid.
Inventors
- 👤 John M. Winslow
- 👤 Ivan R. Maw
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-31 21:18
CPC Classifications
G; G03; G03C; G03C1/00; G03C1/494; G03C1/498; G03C1/49809
Claims Analysis
Total Claims: 9
Claim 1
Independent Claim
90 words
A method of forming a photothermographic emulsion which comprises adding light sensitive silver halide grains with agitation to a dispersion of a long chain fatty acid in water, with no alkali or ammonia salt of said acid present in the dispersion while the acid is maintained above its melting point but below its boiling point, then converting the acid to an ammonia salt or alkali metal salt of the acid, then cooling the dispersion, and thereafter converting the alkali metal or ammonia salt to a silver salt of the acid.
Claim 2
Independent Claim
90 words
A method of forming a photothermographic emulsion which comprises adding light sensitive silver halide grains with agitation to a dispersion of a long chain fatty acid in water, with no alkali or ammonia salt of said acid present in the dispersion while the acid is maintained above its melting point but below its boiling point, then converting the acid to an ammonia salt or alkali metal salt of the acid, then cooling the dispersion, and thereafter converting the alkali metal or ammonia salt to a silver salt of the acid.
Claim 3
Dependent Claim
27 words
The process of claim 1 wherein said long chain fatty acid comprises an alkyl group of 8 to 28 carbon atoms having a terminal carboxylic acid group.
Claim 4
Dependent Claim
18 words
The method of claim 1 wherein the silver halide grains are added to the dispersion by precipitation therein.
Claim 5
Dependent Claim
23 words
The method of claim 3 wherein the long chain fatty acid is comprised of fatty acids having 14 to 24 carbon atoms therein.
Claim 6
Dependent Claim
33 words
The method of claim 3 wherein the emulsion is then coated with an organic reducing agent for silver ions onto a substrate and dried at a temperature which will not develop the emulsion.
Claim 7
Dependent Claim
18 words
The method of claim 1 wherein the silver halide grains are added to the dispersion as preformed grains.
Claim 8
Dependent Claim
23 words
The method of claim 6 wherein the long chain fatty acid is comprised of fatty acids having 14 to 24 carbon atoms therein.
Claim 9
Dependent Claim
33 words
The method of claim 6 wherein the emulsion is then coated with an organic reducing agent for silver ions onto a substrate and dried at a temperature which will not develop the emulsion.
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USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1982-07-16 | 1983-01-15 | 1983-07-17 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1986-07-16 | 1987-01-15 | 1987-07-17 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1990-07-16 | 1991-01-15 | 1991-07-17 | $7700.00 | Window Closed / Lapsed |