US5024929A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Method of preparing coupler dispersions for photographic use
Assignee: Eastman Kodak Co
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Filing: 1990-04-30
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Granted: 1991-06-18
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Expires: 2010-04-30
Abstract
Abstract A method of preparing a coupler dispersion in gelatin by separating the auxiliary coupler solvent using a hydrophilic membrane having a pure size less than 175 Angstroms.
Inventors
- 👤 Edgar P. Lougheed
- 👤 Carl B. Richenberg
- 👤 Stephen P. Chen
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-03 09:11
CPC Classifications
G; G03; G03C; G03C7/00; G03C7/30; G03C7/388; Y; Y10; Y10S; Y10S516/00; Y10S516/924
Claims Analysis
Total Claims: 10
Claim 1
Independent Claim
138 words
A method of preparing a coupler dispersion in gelatin which comprises milling a coupler, a coupler solvent and an auxiliary coupler solvent with an aqueous gelatin solution to form a discontinuous organic phase of submicron droplets containing the coupler, coupler solvent and auxiliary coupler solvent in a continuous aqueous phase of gelatin in water, separating the auxiliary coupler solvent from the organic phase by passing the dispersion containing the auxiliary coupler solvent over one surface of a hydrophilic membrane having an average pore size of less than 175 angstroms while passing water over the other surface of the membrane, said separation step being conducted at a temperature above the point of incipient gelation and for a time sufficient to reduce the concentration of the auxiliary coupler solvent in the dispersion to a concentration less than 1 weight percent.
Claim 2
Independent Claim
138 words
A method of preparing a coupler dispersion in gelatin which comprises milling a coupler, a coupler solvent and an auxiliary coupler solvent with an aqueous gelatin solution to form a discontinuous organic phase of submicron droplets containing the coupler, coupler solvent and auxiliary coupler solvent in a continuous aqueous phase of gelatin in water, separating the auxiliary coupler solvent from the organic phase by passing the dispersion containing the auxiliary coupler solvent over one surface of a hydrophilic membrane having an average pore size of less than 175 angstroms while passing water over the other surface of the membrane, said separation step being conducted at a temperature above the point of incipient gelation and for a time sufficient to reduce the concentration of the auxiliary coupler solvent in the dispersion to a concentration less than 1 weight percent.
Claim 3
Dependent Claim
15 words
The method of claim 1 wherein a surfactant is added to the aqueous gelatin solution.
Claim 4
Dependent Claim
19 words
The method of claim 1 wherein the average pore size of the hydrophilic membrane is less than 100 angstroms.
Claim 5
Dependent Claim
19 words
The method of claim 1 wherein the average pore size of the hydrophilic membrane is less than 75 angstroms.
Claim 6
Dependent Claim
21 words
The method of claim 1 wherein the concentration of the auxiliary coupler solvent is reduced to less than 0.3 weight percent.
Claim 7
Dependent Claim
21 words
The method of claim 1 wherein the concentration of the auxiliary coupler solvent is reduced to less than 0.1 weight percent.
Claim 8
Dependent Claim
23 words
The method of claim 1 wherein the temperature is maintained with a range of about 10° C. above the point of incipient gelation.
Claim 9
Dependent Claim
23 words
The method of claim 1 wherein the temperature is maintained with a range of about 5° C. above the point of incipient gelation.
Claim 10
Dependent Claim
25 words
The method of claim 1 wherein after removal of the auxiliary coupler solvent, the concentration of the coupler in the dispersion is increased by ultrafiltration.
References Cited (Backward Citations)
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1994-06-17 | 1994-12-17 | 1995-06-18 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1998-06-17 | 1998-12-17 | 1999-06-18 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2002-06-17 | 2002-12-17 | 2003-06-18 | $7700.00 | Window Closed / Lapsed |