US3878121A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Method of encapsulation by coacervation, and the substances obtained
Assignee: Societe Nationale des Poudres et Explosifs
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Filing: 1972-12-07
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Granted: 1975-04-15
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Expires: 1992-12-07
Abstract
Abstract The present invention relates to a method of encapsulation by coacervation of fine particles of a very reactive substance such as an alkali metal or a very powerful reducing agent. The said substance is suspended in a polyurethane resin solution made up of constituents which do not react with the substance, the coacervate is obtained by adding more of one of the constituents of the solution, the resulting mixture is dispersed in a slightly polar liquid which does not mix with the mixture and contains in solution an agent for cross-linking polyurethane resin, and the encapsulated substance is then separated from the liquid and dried.
Inventors
- 👤 Gerard Roche
- 👤 Bernard Dumas
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-01 07:40
CPC Classifications
C; C08; C08G; C08G18/00; C08G18/06; C08G18/28; C08G18/40; C08G18/48; C08G18/487; C08G18/4879; B; B01; B01J; B01J13/00; B01J13/02; B01J13/06; B01J13/10; Y; Y10; Y10T; Y10T428/00; Y10T428/29; Y10T428/2982; Y10T428/2989; Y10T428/2991; Y10T428/2998
Claims Analysis
Total Claims: 13
Claim 1
Independent Claim
117 words
A METHOD OF ENCAPSULATING A SOLID SUBSTANCE WHICH IS HIGHLY REACTIVE WITH THE WATER IN THE AMBIENT ATMOSPHERE, BY COACERVATION, WHICH COMPRISES PREPARING A SOLUTION OF A POLYURETHANE RESIN IN A MIXTURE OF AT LEAST TWO SOLVENTS WHICH DO NOT REACT WITH SAID SUBSTANCE, DISPERSING IN THE SAID SOLUTION DISCRETE PARTICLES OF SAID SOLID SUBSTANCE, ADDING TO SAID DISPERSIONN A SUPPLEMENTARY VOLUME OF ONE OF SAID SOLVENTS WHEREBY THE RESIN UNDERGOES COACERVATION AND DEPOSITS ON THE DISPERSED PARTICLES, DISPERSING THE RESULTING MIXTURE IN A SLIGHTLY POLAR LIQUID NON MISCIBLE WITH THE MIXTURE AND CONTAINING A DIISOCYANATE COMPOUND WHEREBY CROSS-LINKING OF THE POLYURETHANE RESULTS, STIRRING THE DISPERSED MIXTURE, SEPARATING AND DRYING THE ENCAPSULATED PARTICLES OF SAID SOLID SUBSTANCE.
Claim 2
Independent Claim
117 words
A METHOD OF ENCAPSULATING A SOLID SUBSTANCE WHICH IS HIGHLY REACTIVE WITH THE WATER IN THE AMBIENT ATMOSPHERE, BY COACERVATION, WHICH COMPRISES PREPARING A SOLUTION OF A POLYURETHANE RESIN IN A MIXTURE OF AT LEAST TWO SOLVENTS WHICH DO NOT REACT WITH SAID SUBSTANCE, DISPERSING IN THE SAID SOLUTION DISCRETE PARTICLES OF SAID SOLID SUBSTANCE, ADDING TO SAID DISPERSIONN A SUPPLEMENTARY VOLUME OF ONE OF SAID SOLVENTS WHEREBY THE RESIN UNDERGOES COACERVATION AND DEPOSITS ON THE DISPERSED PARTICLES, DISPERSING THE RESULTING MIXTURE IN A SLIGHTLY POLAR LIQUID NON MISCIBLE WITH THE MIXTURE AND CONTAINING A DIISOCYANATE COMPOUND WHEREBY CROSS-LINKING OF THE POLYURETHANE RESULTS, STIRRING THE DISPERSED MIXTURE, SEPARATING AND DRYING THE ENCAPSULATED PARTICLES OF SAID SOLID SUBSTANCE.
Claim 3
Dependent Claim
27 words
A method according to claim 1 wherein the polyurethane resin solution used contains methylene chloride and chloroform and the coacervate is obtained by adding more methylene chloride.
Claim 4
Dependent Claim
22 words
A method according to claim 1 wherein the polyurethane resin used contains phenoxy groups and its degree of polymerisation is approximately 100.
Claim 5
Dependent Claim
15 words
A method according to claim 1 wherein the slightly polar liquid is a fluorochlorinated hydrocarbon.
Claim 6
Dependent Claim
15 words
A method according to claim 4, wherein the fluorochlorinated hydrocarbon used is trifluorotrichloroethane or difluorotetrachloroethane.
Claim 7
Dependent Claim
16 words
A method according to claim 4 wherein the diisocyanate compound is toluene diisocyanate or hexamethylene diisocyanate.
Claim 8
Dependent Claim
22 words
A method according to claim 1, wherein the polyurethane solution used contains the following substances within the following limiting concentrations by weight:
Claim 9
Dependent Claim
26 words
A method according to claim 1, wherein the coacervate is obtained by adding from 2 to 5 volumes of methylene chloride to the polyurethane resin solution.
Claim 10
Dependent Claim
22 words
The method according to claim 1 wherein the solid substance is an alkali metal or a simple or a complex hydride thereof.
Claim 11
Independent Claim
42 words
A method of encapsulating solid particles of an alkali metal or a simple or complex hydride thereof by coacervation, which comprises preparing a solution of phenoxy polyurethane resin in a mixture of methylene chloride and chloroform of the following composition by weight:
Claim 12
Independent Claim
42 words
A method of encapsulating solid particles of an alkali metal or a simple or complex hydride thereof by coacervation, which comprises preparing a solution of phenoxy polyurethane resin in a mixture of methylene chloride and chloroform of the following composition by weight:
Claim 13
Dependent Claim
10 words
A substance encapsulated by the method according to claim 10.
References Cited (Backward Citations)
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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) | 1978-04-14 | 1978-10-14 | 1979-04-15 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1982-04-14 | 1982-10-14 | 1983-04-15 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1986-04-14 | 1986-10-14 | 1987-04-15 | $7700.00 | Window Closed / Lapsed |