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US4217241A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Process for the microcapsulation of organophosphoric acid derivative-containing agricultural chemicals
Assignee: Kureha Corp
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Filing: 1978-04-05
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Granted: 1980-08-12
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Expires: 1998-04-05
Abstract
Abstract The invention relates to a process for the preparation of microcapsules of organo-phosphoric acid derivative as capsule core. The derivative has a partial mutual solubility with water. The main feature of the invention is the provision of an inner provisional solid capsule shell of a high molecular hydrophobic substance, such as polymethyl methacrylate. This substance is liable to form a shell on each of the droplets by sedimenting under aqueous condition, while it is capable of dissolving into the capsule core substance, when subject to non-aqueous condition which is established after formation of a permanent outer shell on the provisional shell of each capsule. The provisional shell-forming substance is polymethyl methacrylate, polystyrene, polyvinyl chloride or polyvinyl acetate.
Inventors
- 👤 Yoshio Okada
- 👤 Yuriko Igarashi
- 👤 Kozyu Watanabe
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-23 18:25
CPC Classifications
B; B01; B01J; B01J13/00; B01J13/02; B01J13/20; A; A01; A01N; A01N25/00; A01N25/26; A01N25/28; Y; Y10; Y10T; Y10T428/00; Y10T428/29; Y10T428/2982; Y10T428/2984; Y10T428/2985; Y10T428/2987
Claims Analysis
Total Claims: 3
Claim 1
Independent Claim
167 words
A process for the production of microcapsules having a permanent outer shell consisting essentially of a material selected from the group consisting of a polycation colloid and a polyanion colloid and having a capsule core substance consisting essentially of an organo-phosphoric acid derivative, said process comprising the steps of: (a) adding from about 0.1 to 10 parts by weight of a hydrophobic polymer selected from the group consisting of polymethyl methacrylate, polystyrene, polyvinyl chloride and polyvinyl acetate to 100 parts by weight of said core substance; (b) dispersing and emulsifying the resulting core substance-polymer mixture in an aqueous medium to produce microdroplets provisionally covered with a layer composed of said hydrophobic polymer; (c) subjecting the microdroplets to the conventional complex coacervation process to form capsules having an outermost solid membrane layer on each of said provisionally coated droplets; (d) separating the capsules from the dispersion phase; and (e) drying the resultant capsules whereby the provisional, hydrophobic polymer layer dissolves into the core substance to produce mono-layer capsules.
Claim 2
Dependent Claim
167 words
A process for the production of microcapsules having a permanent outer shell consisting essentially of a material selected from the group consisting of a polycation colloid and a polyanion colloid and having a capsule core substance consisting essentially of an organo-phosphoric acid derivative, said process comprising the steps of: (a) adding from about 0.1 to 10 parts by weight of a hydrophobic polymer selected from the group consisting of polymethyl methacrylate, polystyrene, polyvinyl chloride and polyvinyl acetate to 100 parts by weight of said core substance; (b) dispersing and emulsifying the resulting core substance-polymer mixture in an aqueous medium to produce microdroplets provisionally covered with a layer composed of said hydrophobic polymer; (c) subjecting the microdroplets to the conventional complex coacervation process to form capsules having an outermost solid membrane layer on each of said provisionally coated droplets; (d) separating the capsules from the dispersion phase; and (e) drying the resultant capsules whereby the provisional, hydrophobic polymer layer dissolves into the core substance to produce mono-layer capsules.
Claim 3
Dependent Claim
25 words
The process of claim 1, wherein the organo-phosphoric acid derivative is selected from the group consisting of dimethyl-2, 2-dichlorovinyl phosphate and dimethyl-1, 2-dibromo-2, 2-dichloroethyl phosphate.
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) | 1983-08-12 | 1984-02-11 | 1984-08-12 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1987-08-12 | 1988-02-11 | 1988-08-12 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1991-08-12 | 1992-02-11 | 1992-08-12 | $7700.00 | Window Closed / Lapsed |