US3719494A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Silver halide emulsion containing a dihydroaromatic quaternary salt nucleating agent and the use thereof
Assignee: Eastman Kodak Co
•
Filing: 1970-10-30
•
Granted: 1973-03-06
•
Expires: 1990-10-30
Abstract
Abstract Reactive cyclammonium quaternary salts including a dihydroaromatic ring nucleus, a dihydropyridinium nucleus for example, are useful nucleating agents in direct positive photographic emulsions. The salts include such compounds as a 1,2-dihydro-3-methyl-4-phenylprido( 2,1-b)-5-phenylbenzoxazolium salt. They are conveniently prepared by reacting an appropriate cyclammonium precursor compound in an organic solvent medium for a time sufficient to form the dihydroaromatic derivative.
Inventors
- 👤 D Kurtz
- 👤 D Heseltine
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-29 17:44
CPC Classifications
G; G03; G03C; G03C1/00; G03C1/005; G03C1/485; G03C1/48538; G03C1/48546; Y; Y10; Y10S; Y10S430/00; Y10S430/141
Claims Analysis
Total Claims: 9
Claim 1
Independent Claim
30 words
A direct positive silver halide emulsion that forms latent images predominantly inside the silver halide grains, said emulsion containing a nucleating amount of a dihydroaromatic quaternary salt having the formula:
Claim 2
Dependent Claim
30 words
A direct positive silver halide emulsion that forms latent images predominantly inside the silver halide grains, said emulsion containing a nucleating amount of a dihydroaromatic quaternary salt having the formula:
Claim 3
Dependent Claim
17 words
A direct positive silver halide emulsion as described in claim 1, where X represents a halide anion.
Claim 4
Dependent Claim
20 words
A direct positive silver halide emulsion as described in claim 1 wherein the emulsion has a dye-forming coupler contiguous thereto.
Claim 5
Dependent Claim
38 words
A direct positive silver halide emulsion as described in claim 1 wherein the dihydroaromatic quaternary salt is present at a concentration of from about 50 mg to about 1,500 mg per mole of silver halide in said emulsion.
Claim 6
Dependent Claim
51 words
A direct positive silver halide emulsion that forms latent images predominantly inside the silver halide grains, said emulsion containing a nucleating amount of a dihydroaromatic quaternary salt selected from the group consisting of: a. 1,2-Dihydro-3-methyl-4-phenylpyrido(2,1-b)-benzothiazolium bromide, b. 1,2-Dihydro-3-methyl-4-phenylpyrido(2,1-b)-5-phenylbenzoxalzolium bromide, c. 1,2-Dihydro-3,4-dimethylpyrido(2,1-b)-benzothiazolium bromide, d. 1,2-Dihydro-3-methyl-4-phenoxy-pyrido(2,1-b)-benzothiazolium bromide e. 4,4''-Ethylenebis(1,2-dihydro-3-methylpyrido-(2,1-b)benzothiazolium bromide), f. 1,2-Dihydro-3-methyl-4-phenylpyrido(2,1-b)-benzoselenazolium bromide.
Claim 7
Dependent Claim
51 words
A direct positive silver halide emulsion that forms latent images predominantly inside the silver halide grains, said emulsion containing a nucleating amount of a dihydroaromatic quaternary salt selected from the group consisting of: a. 1,2-Dihydro-3-methyl-4-phenylpyrido(2,1-b)-benzothiazolium bromide, b. 1,2-Dihydro-3-methyl-4-phenylpyrido(2,1-b)-5-phenylbenzoxalzolium bromide, c. 1,2-Dihydro-3,4-dimethylpyrido(2,1-b)-benzothiazolium bromide, d. 1,2-Dihydro-3-methyl-4-phenoxy-pyrido(2,1-b)-benzothiazolium bromide e. 4,4''-Ethylenebis(1,2-dihydro-3-methylpyrido-(2,1-b)benzothiazolium bromide), f. 1,2-Dihydro-3-methyl-4-phenylpyrido(2,1-b)-benzoselenazolium bromide.
Claim 8
Dependent Claim
20 words
A direct positive silver halide emulsion as described in claim 1 wherein the emulsion is a gelatino silver halide emulsion.
Claim 9
Dependent Claim
17 words
A direct-positive silver halide emulsion as described in claim 1 wherein the silver halide comprises silver chlorobromoiodide.
References Cited (Backward Citations)
US2685514A
Cited
US3367778A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1976-03-05 | 1976-09-04 | 1977-03-06 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1980-03-05 | 1980-09-04 | 1981-03-06 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1984-03-05 | 1984-09-04 | 1985-03-06 | $7700.00 | Window Closed / Lapsed |