US5156914A
Expired / Lapsed
US
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Process for producing particulate silicon encapsulated products
Assignee: ISP CAPITAL Inc
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Filing: 1991-05-06
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Granted: 1992-10-20
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Expires: 2011-05-06
Abstract
Abstract This invention relates to an anhydrous, liquid phase process for entrapping droplets of a silicon compound in an organic polymer which involves precharging a reactor at between about 50° and about 80° C. with a polymerization initiator and a non-polar solvent in which the silicon compound is soluble; adding to the precharged reactor, silicon compound under vigorous agitation and gradually introducing from about 50 to about 99 wt. %, based on silicon compound, of a polymerizably precipitatable, aliphatically unsaturated monomer at a controlled rate; continuously polymerizing the monomer component, under vigorous agitation with the silicon compound, at between about 50° and about 165° C. while maintaining a desired monomer level of not more than 10% in the reactor and recovering a solid particulate product of silicon droplets entrapped in said polymerized monomer.
Inventors
- 👤 Jenn S. Shih
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-31 04:52
CPC Classifications
A; A61; A61K; A61K8/00; A61K8/18; A61K8/72; A61K8/81; A61K8/817; A61K8/8176; A61K8/02; A61K8/11; A61K8/84; A61K8/89; A61K8/891; A61Q; A61Q5/00; A61Q5/02; C; C08; C08F; C08F2/00; C08F2/12; C08F2/14; C08F26/00; C08F26/06; A61K2800/00; A61K2800/40; A61K2800/41; A61K2800/412; Y; Y10; Y10S; Y10S507/00; Y10S507/902; Y10S525/00; Y10S525/936; Y10S526/00; Y10S526/922; Y10T; Y10T428/00; Y10T428/29; Y10T428/2982; Y10T428/2984; Y10T428/2985; Y10T428/2987
Claims Analysis
Total Claims: 25
Claim 1
Independent Claim
196 words
A liquid phase process for encapsulating silicone droplets in a water soluble or water swellable polymer under anhydrous, oxygen free conditions comprising (a) precharging a reactor with a reaction solvating amount of a non-polar hydrocarbon solvent and an effective polymerization promoting amount of a free radical polymerization initiator at a temperature of from about 50° to about 80° C.; (b) feeding to said precharged reactor a silicon compound which is soluble in said solvent and gradually introducing to said reactor, at a rate of from about 0.08 to about 2.5 g/minute/1000 g of solvent with vigorous agitation, between about 50 and about 99 wt. %, based on said silicon compound, of a polymerizably precipitatable, aliphatically unsaturated monomer; (c) continuously polymerizing said monomer optionally with introduction of additional amounts of initiator and precipitating polymer under vigorous agitation with said silicon compound at a temperature of from about 50° to about 165° C. wile maintaining the precipitated solids level at between about 10% and about 50% and the monomer level below about 10% in the reactor; (d) separating precipitated polymer containing entrapped silicon compound droplets from the reaction mixture and (e) drying said precipitate to a particulate product.
Claim 2
Dependent Claim
196 words
A liquid phase process for encapsulating silicone droplets in a water soluble or water swellable polymer under anhydrous, oxygen free conditions comprising (a) precharging a reactor with a reaction solvating amount of a non-polar hydrocarbon solvent and an effective polymerization promoting amount of a free radical polymerization initiator at a temperature of from about 50° to about 80° C.; (b) feeding to said precharged reactor a silicon compound which is soluble in said solvent and gradually introducing to said reactor, at a rate of from about 0.08 to about 2.5 g/minute/1000 g of solvent with vigorous agitation, between about 50 and about 99 wt. %, based on said silicon compound, of a polymerizably precipitatable, aliphatically unsaturated monomer; (c) continuously polymerizing said monomer optionally with introduction of additional amounts of initiator and precipitating polymer under vigorous agitation with said silicon compound at a temperature of from about 50° to about 165° C. wile maintaining the precipitated solids level at between about 10% and about 50% and the monomer level below about 10% in the reactor; (d) separating precipitated polymer containing entrapped silicon compound droplets from the reaction mixture and (e) drying said precipitate to a particulate product.
Claim 3
Dependent Claim
53 words
The process of claim 1 wherein said silicon compound has the formula ##STR2## wherein n has a value of from 0 to 50, R l , R 2 , R 3 and R 4 are each individually hydrogen, chloro, hydroxyalkyl, lower alkyl or phenyl and R 3 can also be an alkylene acrylate.
Claim 4
Dependent Claim
29 words
The process of claim 1 wherein said monomer is selected from the group of acrylic acid, acrylamide, N-vinyl pyrrolidone, N-vinyl caprolactam and mixtures of N-vinyl pyrrolidone and N-vinyl caprolactam.
Claim 5
Dependent Claim
32 words
The process of claim 1 wherein said monomer is selected from the group of acrylic acid, acrylamide, N-vinylpyrrolidone, N-vinyl caprolactam, and mixtures of N-vinylpyrrolidone and/or N-vinyl caprolactam with a polyfunctional polymerizable comonomer.
Claim 6
Dependent Claim
34 words
The process of claim 4 wherein said comonomer is selected from the group of an acrylic acid, vinyl acetate, a C 1 to C 4 alkyl acrylate, N,N-dimethylaminoethyl methacrylate, N,N-dimethylaminomethyl acrylate, and N,N-dimethylaminopropyl methacrylate.
Claim 7
Dependent Claim
40 words
The process of claim 4 wherein the polyfunctional comonomer is a crosslinking agent selected from the group of triallyl-1,3,5-triazine-2,4,6-(1H,3H,5H)trione, N,N-divinyl-2-imidazolidone, the divinyl ether of diethylene glycol, 2,4,6-triallyloxy-1,3,5-triazine, ethylene glycol diacrylate, 1,7-octadiene, divinyl benzene, 1,9-decadiene, methylene bis(acrylamide) and pentaerythritol triallyl ether.
Claim 8
Dependent Claim
15 words
The process of claim 1 wherein said solvent is C 2 to C 20 alkane.
Claim 9
Dependent Claim
10 words
The process of claim 7 wherein said alkane is cyclohexane.
Claim 10
Dependent Claim
42 words
The process of claim 8 wherein said monomer is N-vinyl pyrrolidone optionally containing less than 50% cross-linking agent and the monomer is fed to said precharged reactor at a rate of from about 0.8 to about 1.3 g/minute/1000 g. of said cyclohexane.
Claim 11
Dependent Claim
10 words
The process of claim 7 wherein said alkane is heptane.
Claim 12
Dependent Claim
42 words
The process of claim 10 wherein said monomer is N-vinyl pyrrolidone optionally containing less than 50% cross-linking agent and the monomer is fed to said precharged reactor at a rate of from about 0.3 to about 0.8 g/minute/1000 g. of said heptane.
Claim 13
Dependent Claim
39 words
The process of claim 1 wherein the entire reaction is carried out at a temperature below 100° C. in the presence of a low temperature free-radical peroxide initiator and the monomer concentration in the reactor is maintained below 6%.
Claim 14
Dependent Claim
32 words
The process of claim 12 wherein between about 0.2 and about 5 wt. % based on monomer of the low temperature initiator is added continuously or in increments to the reaction mixture.
Claim 15
Dependent Claim
88 words
The process of claim 1 wherein an initial stage of the polymerization reaction is carried out at a temperature of between about 60° and 70° C. in the presence of a low temperature initiator and a final stage of the polymerization reaction is carried out at a temperature of between about 110° and about 130° C. in the presence of a high temperature free-radical peroxide initiator, having a 10 hour half life at 100° C. or above, and the monomer concentration in the reactor is maintained below 2%.
Claim 16
Dependent Claim
16 words
The process of claim 14 wherein the residual monomer in the reactor is maintained below 1%.
Claim 17
Dependent Claim
36 words
The process of claim 14 wherein between about 0.2 and about 5 wt. % based on monomer of the low temperature initiator is introduced gradually or at a plurality of stage during the low temperature polymerization.
Claim 18
Dependent Claim
30 words
The process of claim 14 wherein between about 0.3 and about 1 wt. % based on monomer of the high temperature initiator is introduced to the high temperature polymerization reaction.
Claim 19
Dependent Claim
23 words
The process of claim 1 wherein the concentration of silicon compound in said solvent is between about 0.5 and about 10 wt. %.
Claim 20
Dependent Claim
23 words
The process of claim 1 wherein the wt. % of silicon compound with respect to monomer is between about 1 and about 50%.
Claim 21
Dependent Claim
19 words
The process of claim 19 wherein said wt. % of silicon compound is between about 5 and about 30%.
Claim 22
Dependent Claim
14 words
The product of claim 3 which is a white powder containing 10-20% silicon compound.
Claim 23
Dependent Claim
18 words
The product of claim 21 wherein said silicon compound droplet is encapsulated in a non-crosslinked N-vinylpyrrolidone homopolymeric structure.
Claim 24
Dependent Claim
14 words
The product of claim 4 which is a white powder containing 10-20% silicon compound.
Claim 25
Dependent Claim
17 words
The product of claim 23 wherein said silicon compound droplet is encapsulated in a cross-linked N-vinylpyrrolidone structure.
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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) | 1995-10-20 | 1996-04-20 | 1996-10-20 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1999-10-20 | 2000-04-20 | 2000-10-20 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2003-10-20 | 2004-04-20 | 2004-10-20 | $7700.00 | Window Closed / Lapsed |