US4272398A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Microencapsulation process
Assignee: United States Department of Agriculture
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Filing: 1979-06-15
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Granted: 1981-06-09
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Expires: 1999-06-15
Abstract
Abstract Pesticides, insect growth regulators and other substances are encapsulated by dissolving the substance to be encapsulated and a biodegradable polymer in a suitable organic solvent, dispersing the solution in an aqueous medium and stirring until the solvent evaporates to form a matrix of the substance in the polymer.
Inventors
- 👤 Howard Jaffe
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-23 15:35
CPC Classifications
B; B29; B29C; B29C67/00; B29C67/24; B29C67/247; A; A01; A01N; A01N25/00; A01N25/26; A01N25/28; B01; B01J; B01J13/00; B01J13/02; B01J13/06; B01J13/12; B01J13/125; B29C67/0037; B29K; B29K2995/00; B29K2995/0037; B29K2995/0056; B29K2995/0059; B29K2995/006; Y; Y10; Y10T; Y10T428/00; Y10T428/29; Y10T428/2982; Y10T428/2989
Claims Analysis
Total Claims: 7
Claim 1
Independent Claim
109 words
A process for one-phase encapsulation of organic compounds selected from the group consisting of famphur and stirofos systemic tick pesticides for oil suspension formulations and of methoprene and 2-ethoxy-9(p-isopropylphenyl)-2,6-dimethylnonane insect growth regulators comprising dissolving said compound and a biodegradable polymer selected from the group consisting of polylactic acid and copolymers of lactic and glycolic acids in methylene chloride, agitating until complete solution of the compound-polymer mixture is affected, dispersing said solution in an aqueous medium containing an anionic surfactant, and stirring said dispersion until the solvent evaporates, thereby forming a soapy white suspension of said compound in said polymer, filtering, washing, drying and sizing to white powder one-phase particles.
Claim 2
Dependent Claim
109 words
A process for one-phase encapsulation of organic compounds selected from the group consisting of famphur and stirofos systemic tick pesticides for oil suspension formulations and of methoprene and 2-ethoxy-9(p-isopropylphenyl)-2,6-dimethylnonane insect growth regulators comprising dissolving said compound and a biodegradable polymer selected from the group consisting of polylactic acid and copolymers of lactic and glycolic acids in methylene chloride, agitating until complete solution of the compound-polymer mixture is affected, dispersing said solution in an aqueous medium containing an anionic surfactant, and stirring said dispersion until the solvent evaporates, thereby forming a soapy white suspension of said compound in said polymer, filtering, washing, drying and sizing to white powder one-phase particles.
Claim 3
Dependent Claim
86 words
An encapsulation process for one-phase encapsulation of compounds and mixtures of compounds soluble in volatile organic solvents comprising dissolving said compound and a biodegradable polymer selected from the group consisting of polylactic acid and copolymers of lactic and glycolic acids in a suitable organic solvent, dispersing the solution in an aqueous medium containing an anionic surfactant, and stirring said dispersion until the solvent evaporates, thereby forming a soapy white suspension of said compound in said polymer, filtering, washing, drying and sizing to aggregates of one-phase particles.
Claim 4
Dependent Claim
86 words
An encapsulation process for one-phase encapsulation of compounds and mixtures of compounds soluble in volatile organic solvents comprising dissolving said compound and a biodegradable polymer selected from the group consisting of polylactic acid and copolymers of lactic and glycolic acids in a suitable organic solvent, dispersing the solution in an aqueous medium containing an anionic surfactant, and stirring said dispersion until the solvent evaporates, thereby forming a soapy white suspension of said compound in said polymer, filtering, washing, drying and sizing to aggregates of one-phase particles.
Claim 5
Dependent Claim
18 words
The process of claim 2 wherein said aggregates have a particle size of from about 177μ to 595μ.
Claim 6
Dependent Claim
25 words
The process of claim 3 wherein the aggregates are formed of individual, generally spherical-shaped microcapsules, said microcapsules having diameters of from about 5μ to 162μ.
Claim 7
Dependent Claim
16 words
The process of claim 4 wherein said microcapsules contain from about 23.6 to 47.4% active material.
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) | 1984-06-08 | 1984-12-08 | 1985-06-09 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1988-06-08 | 1988-12-08 | 1989-06-09 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1992-06-08 | 1992-12-08 | 1993-06-09 | $7700.00 | Window Closed / Lapsed |