US5242964A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Process for the preparation of aqueous dispersions of magnetizable polymer particles with a desired size narrow distribution, and aqueous dispersions thereof, and uses thereof
Assignee: Prolabo SA
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Filing: 1991-07-29
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Granted: 1993-09-07
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Expires: 2011-07-29
Abstract
Abstract A process for the preparation of aqueous dispersions of magnetizable polymer particles with a narrow distribution from aqueous dispersions with a wide distribution. The amount of water in the aqueous dispersion with a wide distribution is adjusted so that the proportion by weight of magnetizable polymer particles is between about 1 and 40% of said dispersion. The surfactant concentration of the dispersion after the water adjustment is increased until two phases are obtained: a so-called liquid phase and a so-called solid phase. After separation of these two phases is accomplished, these steps are repeated as desired. An aqueous dispersion with a narrow size distribution is recovered.
Inventors
- 👤 Jerome Bibette
- 👤 Dominique Charmot
- 👤 Gilbert Schorsch
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-30 07:40
CPC Classifications
C; C08; C08J; C08J3/00; C08J3/02; C08J3/03; H; H01; H01F; H01F1/00; H01F1/44; Y; Y10; Y10S; Y10S530/00; Y10S530/81; Y10S530/812; Y10S530/815; Y10T; Y10T428/00; Y10T428/29; Y10T428/2982; Y10T428/2991; Y10T428/2993; Y10T428/2995
Claims Analysis
Total Claims: 21
Claim 1
Independent Claim
176 words
A process for the preparation of an aqueous dispersion of magnetizable polymer particles having a narrow size distribution from an aqueous dispersion of said particles having a wide size distribution, comprising the steps of: (a) providing an aqueous dispersion having a wide size distribution of magnetizable polymer particles and having a solids content by weight of polymer particles in the range of from about 1 and 40%, said wide size distribution of polymer particles having a standard deviation of about 60% or more; (b) adding a surfactant to the dispersion of step (a) until two phases are obtained, said two phases constituting a liquid phase which is relatively free of said particles, and a solid phase in which said particles are relatively associated therein; (c) separating said two phases obtained in step (b); and (d) optionally repeating step (a), (b) and (c) on said solid phase separated in step (c) at least once to provide an aqueous dispersion having a narrow size distribution of polymer particles having a standard deviation less than or equal to 30%.
Claim 2
Dependent Claim
176 words
A process for the preparation of an aqueous dispersion of magnetizable polymer particles having a narrow size distribution from an aqueous dispersion of said particles having a wide size distribution, comprising the steps of: (a) providing an aqueous dispersion having a wide size distribution of magnetizable polymer particles and having a solids content by weight of polymer particles in the range of from about 1 and 40%, said wide size distribution of polymer particles having a standard deviation of about 60% or more; (b) adding a surfactant to the dispersion of step (a) until two phases are obtained, said two phases constituting a liquid phase which is relatively free of said particles, and a solid phase in which said particles are relatively associated therein; (c) separating said two phases obtained in step (b); and (d) optionally repeating step (a), (b) and (c) on said solid phase separated in step (c) at least once to provide an aqueous dispersion having a narrow size distribution of polymer particles having a standard deviation less than or equal to 30%.
Claim 3
Dependent Claim
26 words
The process of claim 1, further comprising the step of: (e) diluting said aqueous dispersion with said narrow size distribution to provide a desired solids content.
Claim 4
Dependent Claim
17 words
The process of claim 1, wherein said standard deviation is in the range of 15 to 25%.
Claim 5
Dependent Claim
17 words
The process of claim 3, wherein said standard deviation is in the range of 3 to 5%.
Claim 6
Dependent Claim
29 words
The process of claim 1, wherein said aqueous dispersion with a wide size distribution contains magnetizable particles with a size distribution in the range from 0.01 to 20 microns.
Claim 7
Dependent Claim
27 words
The process of claim 1, wherein said magnetizable polymer particles in step (a) contain in the range of 0.5 to 70% by weight of a magnetic charge.
Claim 8
Dependent Claim
32 words
The process of claim 1, wherein step (a), the solids content by weight of said magnetizable polymer particles having a narrow size distribution ranges from 4 to 15% of said aqueous dispersion.
Claim 9
Dependent Claim
30 words
The process of claim 1, wherein the surfactant introduced in step (b) to increase said surfactant concentration is selected from anionic, cationic, amphoteric or nonionic surfactants, or compatible mixtures thereof.
Claim 10
Dependent Claim
27 words
The process of claim 1, wherein the surfactant concentration introduced in step (b) is increased to the range from 2.5 to 20 times the critical micellar concentration.
Claim 11
Dependent Claim
26 words
The process of claim 9, wherein the surfactant concentration in step (b) is increased to the range from 2.5 to 10 times the critical micellar concentration.
Claim 12
Dependent Claim
26 words
The process of claim 1, wherein said steps (a), (b) and (c) are repeated up to 8 times on the solid phase separated in step (c).
Claim 13
Dependent Claim
27 words
The process of claim 11, wherein said steps (a), (b) and (c) are repeated from 2 to 5 times on the solid phase separated in step (c).
Claim 14
Dependent Claim
27 words
The process of claim 1, further comprising the step of repeating steps (b) and (c) up to 8 times on the liquid phase separated in step (c).
Claim 15
Dependent Claim
26 words
The process of claim 13, wherein said steps (b) and (c) are repeated from 2 to 5 times on the liquid phase separated in step (c).
Claim 16
Dependent Claim
39 words
An aqueous dispersion comprising a narrow size distribution of magnetizable polymer particles as produced by the process of claim 1, wherein the standard deviation of the narrow size distribution of said particles is less than or equal to 30%.
Claim 17
Dependent Claim
18 words
The aqueous dispersion of claim 15, wherein said standard deviation is in the range from 15 to 25%.
Claim 18
Dependent Claim
18 words
The aqueous dispersion of claim 16, wherein said standard deviation is in the range from 3 to 5%.
Claim 19
Dependent Claim
55 words
A process comprising the step of using an aqueous dispersion of magnetizable polymer particles having a narrow size distribution as produced by the process of claim 1, wherein the standard deviation of the size distribution of said particles is less than or equal to 30%, in a diagnostic test of the radioimmunoassay or immunoenzymatic type.
Claim 20
Dependent Claim
43 words
A magneto-thickening fluid comprising an aqueous dispersion of magnetizable polymer particles having a narrow size distribution as produced by the process of claim 1, wherein the standard deviation of the size distribution of said particles is less than or equal to about 30%.
Claim 21
Dependent Claim
48 words
A diagnostic test of the radioimmunoassay or immunoenzymatic type comprising an aqueous dispersion of magnetizable polymer particles having a narrow sizes distribution as produced by the process of claim 1, wherein the standard deviation of the size distribution of said particles is less than or equal to 30%.
References Cited (Backward Citations)
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Cited
GB1416004A
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US4177253A
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US4358388A
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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) | 1996-09-06 | 1997-03-08 | 1997-09-07 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 2000-09-06 | 2001-03-08 | 2001-09-07 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2004-09-06 | 2005-03-08 | 2005-09-07 | $7700.00 | Window Closed / Lapsed |