Patent US4990431A successfully refreshed from Google Patents.
US4990431A
Expired / Lapsed
US
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Methods of forming stable dispersions of photographic materials
Assignee: Eastman Kodak Co
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Filing: 1989-01-17
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Granted: 1991-02-05
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Expires: 2009-01-17
Abstract
Abstract The invention is performed by providing a first flow of water and surfactant, a second flow comprising solvent, base and photographic material, and mixing said first and second streams and either simultaneously or immediately following thereof neutralizing said streams to prevent hydrolysis of a hydrolyzable surfactant and/or premature precipitation of particles before neutralization. The streams then may be immediately treated for formation into photographic materials. In a preferred method the first and second stream may be brought together immediately prior to a mixer with addition of acid directly into the mixer to neutralize the dispersion of fine particles.
Inventors
- 👤 Pranab Bagchi
- 👤 James T. Beck
- 👤 Lia A. Crede
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-29 22:28
CPC Classifications
G; G03; G03C; G03C1/00; G03C1/005
Claims Analysis
Total Claims: 30
Claim 1
Independent Claim
68 words
A method of preparing aqueous dispersions of a photographic material comprising continuously providing a first solution comprising water and a surfactant, continuously providing a second solution comprising a solvent, base, and photographic material, continuously mixing said first and said second solutions, and immediately neutralizing with an acid solution the mixed solutions to precipitate particles of said photographic material as a fine particle colloidal dispersion of said photographic material.
Claim 2
Independent Claim
68 words
A method of preparing aqueous dispersions of a photographic material comprising continuously providing a first solution comprising water and a surfactant, continuously providing a second solution comprising a solvent, base, and photographic material, continuously mixing said first and said second solutions, and immediately neutralizing with an acid solution the mixed solutions to precipitate particles of said photographic material as a fine particle colloidal dispersion of said photographic material.
Claim 3
Dependent Claim
30 words
The method of claim 1 wherein immediately after mixing, the mixture of the first stream, and second stream is adjusted to a pH of about 6.0 to form stable particles.
Claim 4
Dependent Claim
22 words
The method of claim 2 wherein said neutralizing is to pH of about 6 and performed by the addition of organic acids.
Claim 5
Dependent Claim
17 words
The method of claim 1 wherein said photographic material comprises at least one of the following: ##STR3##
Claim 6
Dependent Claim
22 words
The method of claim 1 wherein said mixing of said first solution and said second solution, and said neutralizing takes place simultaneously.
Claim 7
Dependent Claim
11 words
The method of claim 1 wherein said base comprises sodium hydroxide.
Claim 8
Dependent Claim
23 words
The method of claim 1 wherein the particles in said colloidal dispersion are of a size between about 5 and about 300 nm.
Claim 9
Dependent Claim
37 words
The method of claim 4 wherein after said neutralizing the said colloidal dispersion is immediately processed to remove said solvent and salt by products of neutralizing to prepare the particles for use in forming a photographic element.
Claim 10
Dependent Claim
31 words
The method of claim 2 wherein during said neutralizing the pH is adjusted to about 6 at a location downstream from the initial mixing of said first and said second solutions.
Claim 11
Dependent Claim
13 words
The method of claim 1 wherein said mixing is for about 2 seconds.
Claim 12
Dependent Claim
17 words
The method of claim 2 wherein said neutralizing to a pH of about 6 utilizes acetic acid.
Claim 13
Dependent Claim
17 words
The method of claim 2 wherein said neutralizing to a pH of about 6 utilizes propionic acid.
Claim 14
Dependent Claim
21 words
The method of claim 1 wherein said mixing and said neutralizing is complete in between about 1 and about 10 seconds.
Claim 15
Dependent Claim
18 words
The method of claim 1 wherein said immediately neutralizing is with low mechanical shear and high fluid shear.
Claim 16
Dependent Claim
20 words
The method of claim 1 wherein said immediately neutralizing takes place in less than about two minutes after said mixing.
Claim 17
Dependent Claim
20 words
The method of claim 1 wherein said immediate neutralizing is complete in less than about five seconds after said mixing.
Claim 18
Dependent Claim
14 words
The method of claim 1 wherein the method is operated in a semicontinuous manner.
Claim 19
Dependent Claim
11 words
The method of claim 8 wherein the method is performed continuously.
Claim 20
Dependent Claim
27 words
The method of claim 1 wherein said photographic material comprises at least one member selected from the group comprising couplers, UV absorbers, reducing agents, and developing agents.
Claim 21
Dependent Claim
12 words
The method of claim 1 wherein said photographic material comprises photographic couplers.
Claim 22
Dependent Claim
11 words
The method of claim 1 wherein said surfactant is base degradable.
Claim 23
Dependent Claim
10 words
The method of claim 1 wherein said surfactant is hydrolyzable.
Claim 24
Dependent Claim
38 words
The method of claim 1 wherein said first solution, said second solution, and a neutralizing acid solution are simultaneously mixed to precipitate and immediately neutralize said photographic material in a fine particle colloidal dispersion at about pH 6.0.
Claim 25
Dependent Claim
21 words
The method of claim 8 wherein said dispersion is stable from precipitation at room temperature storage for at least six weeks.
Claim 26
Dependent Claim
25 words
The method of claim 8 wherein dispersion of compounds 1 and 3 are stable from precipitation under room temperature storage for at least 1 year.
Claim 27
Dependent Claim
33 words
The method of claim 1 wherein said first solution and said second solution are mixed and then the mixture of said first and said second solutions is neutralized by addition of an acid.
Claim 28
Dependent Claim
18 words
The method of claim 1 wherein said surfactant is selected from the group consisting of ##STR4## mixtures thereof.
Claim 29
Dependent Claim
10 words
The method of claim 1 wherein said surfactant comprises ##STR5##
Claim 30
Dependent Claim
10 words
The method of claim 1 wherein said surfactant comprises ##STR6##
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