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Stable suspension system for microencapsulated flowable formulations, and method of preparing stable suspension of microcapsules
Assignee: Zeneca Inc
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Filing: 1974-05-01
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Granted: 1979-05-22
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Expires: 1994-05-01
Abstract
Abstract Stable suspension-buffer system for aqueous suspensions of microencapsulated materials which can be obtained by using aluminum hydroxide or ferric hydroxide as the suspending and buffering agent, together with a sequestering agent, a second suspending agent, thereby preventing separation and caking in microcapsule flowable formulations.
Inventors
- 👤 Herbert B. Scher
- 👤 Robert J. Cochran
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-01 12:37
CPC Classifications
A; A01; A01N; A01N25/00; A01N25/26; A01N25/28; B; B01; B01J; B01J13/00; B01J13/02
Claims Analysis
Total Claims: 19
Claim 1
Independent Claim
47 words
A stable aqueous suspension of microencapsulated material comprising microcapsules, a suspending and buffering agent selected from the group consisting of ferric hydroxide and aluminum hydroxide, a sequestering agent, a second suspending agent, the pH of said suspension adjusted to from about pH 9.0 to about pH 12.0.
Claim 2
Dependent Claim
47 words
A stable aqueous suspension of microencapsulated material comprising microcapsules, a suspending and buffering agent selected from the group consisting of ferric hydroxide and aluminum hydroxide, a sequestering agent, a second suspending agent, the pH of said suspension adjusted to from about pH 9.0 to about pH 12.0.
Claim 3
Dependent Claim
51 words
A stable aqueous suspension of microencapsulated material comprising microcapsules with polyurea walls, a suspending and buffering agent selected from the group consisting of ferric hydroxide and aluminum hydroxide, a sequestering agent, a second suspending agent and the pH of said suspension adjusted to from about pH 9.0 to about pH 12.0.
Claim 4
Dependent Claim
51 words
A stable aqueous suspension of microencapsulated material comprising microcapsules with polyurea walls, a suspending and buffering agent selected from the group consisting of ferric hydroxide and aluminum hydroxide, a sequestering agent, a second suspending agent and the pH of said suspension adjusted to from about pH 9.0 to about pH 12.0.
Claim 5
Dependent Claim
49 words
A stable suspension according to claim 2 in which said sequestering agent is selected from the group consisting of polycarboxylic acids, aminopolycarboxylic acids, α-hydroxy acids, orthophosphates, condensed phosphates, 5-sulfo-8-hydroxyquinoline and 3,5-disulfopyrocatechol and said second suspending agent is selected from the group consisting of colloidal minerals and polymeric-type suspending agents.
Claim 6
Dependent Claim
39 words
A stable suspension according to claim 3 in which said second suspending agent is selected from the group consisting of silica, alumina, Montmorillonite clays, attapulgite clay, guar gum, xanthan gum, gum arabic, alginates, carrageenan, carboxymethyl cellulose and hydroxyethyl cellulose.
Claim 7
Dependent Claim
49 words
A stable suspension according to claim 2 in which said sequestering agent is selected from the group consisting of sodium tripolyphosphate and hydrolyzed poly(methyl vinyl ether/maleic anhydride) and a second suspending agent is selected from the group consisting of a xanthan gum and colloidal attapulgite: hydrated magnesium aluminum silicate.
Claim 8
Dependent Claim
64 words
A stable suspension according to claim 5 wherein said suspending and buffering agent is from about 0.1 to about 5.0 percent by weight of aluminum or ferric salt as aluminum trichloride hexahydrate or ferric chloride hexahydrate, the sequestering agent is from about 0.1 to about 5.0 percent by weight and the second suspending agent is from about 0.01 to about 5.0 percent by weight.
Claim 9
Dependent Claim
14 words
A stable suspension according to claim 2 wherein the microencapsulated material is a herbicide.
Claim 10
Dependent Claim
14 words
A stable suspension according to claim 2 wherein the microencapsulated material is an insecticide.
Claim 11
Independent Claim
66 words
The method of preparing a stable suspension of microcapsules comprising the addition to a microcapsule dispersion a sequestering agent and a suspending and buffering agent selected from the group consisting of aluminum chloride and ferric chloride, and a second suspending agent and adjusting the pH of said suspension to from about pH 9.0 to about pH 12.0 to form aluminum hydroxide and ferric hydroxide in situ.
Claim 12
Independent Claim
66 words
The method of preparing a stable suspension of microcapsules comprising the addition to a microcapsule dispersion a sequestering agent and a suspending and buffering agent selected from the group consisting of aluminum chloride and ferric chloride, and a second suspending agent and adjusting the pH of said suspension to from about pH 9.0 to about pH 12.0 to form aluminum hydroxide and ferric hydroxide in situ.
Claim 13
Dependent Claim
48 words
The method according to claim 9 in which said sequestering agent is selected from the group consisting of polycarboxylic acids, aminopolycarboxylic acids, α-hydroxy acids, orthophosphates, condensed phosphates, 5-sulfo-8-hydroxyquinoline and 3,5-disulfopyrocatechol and said second suspending agent is selected from the group consisting of colloidal minerals and polymeric-type suspending agents.
Claim 14
Dependent Claim
37 words
The method according to claim 9 in which said second suspending agent is selected from the group consisting of silica, alumina, Montmorillonite clays, attapulgite clay, guar gum, xanthan gum, gum arabic, alginates, carrageenan, carboxymethyl cellulose and hydroxyethylcellulose.
Claim 15
Dependent Claim
19 words
The method according to claim 9 in which sodium hydroxide is used to adjust the pH of the system.
Claim 16
Dependent Claim
49 words
The method according to claim 9 in which said sequestering agent is selected from the group consisting of sodium tripolyphosphate and hydrolyzed poly(methyl vinyl ether/maleic anhydride) and said second suspending agent is selected from the group consisting of a xanthan gum and colloidal attapulgite; a hydrated magnesium aluminum silicate.
Claim 17
Dependent Claim
12 words
The method of claim 9 in which said microcapsules contain a herbicide.
Claim 18
Dependent Claim
12 words
The method of claim 9 in which said microcapsules contain an insecticide.
Claim 19
Dependent Claim
15 words
The method of claim 9 in which said microcapsules contain a herbicide and antidote therefor.
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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) | 1982-05-21 | 1982-11-20 | 1983-05-22 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1986-05-21 | 1986-11-20 | 1987-05-22 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1990-05-21 | 1990-11-20 | 1991-05-22 | $7700.00 | Window Closed / Lapsed |