US4540629A
Expired / Lapsed
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Hollow microspheres with organosilicon-silicate walls
Assignee: PQ Corp
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Filing: 1984-02-27
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Granted: 1985-09-10
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Expires: 2004-02-27
Abstract
Abstract Hollow microspheres of reduced surface energy and reactivity and of improved packing and sphericity are prepared by simultaneously forming said microspheres and reacting them with an organosilicon compound. The microspheres are prepared by spray drying a solution of alkali metal silicate and a "polysalt." The organosilicon is present as the microspheres are formed, penetrates and reacts to form a shell consisting of a silicate, polysalt and the organosilicon compound. The resulting product is more discrete, more free-flowing, has better packaging characteristics, improved packing factor and improved filler properties when compared to prior-art microspheres.
Inventors
- 👤 Bruce W. Sands
- 👤 Robert J. Nehring, Jr.
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-23 03:22
CPC Classifications
C; C04; C04B; C04B20/00; C04B20/10; C04B20/1051; B; B01; B01J; B01J13/00; B01J13/02; B01J13/04; C03; C03B; C03B19/00; C03B19/10; C03B19/1005; C03B19/106; C03B19/1065; C03B19/107; C03C; C03C11/00; C03C11/002; C03C17/00; C03C17/28; C03C17/30; Y; Y10; Y10T; Y10T428/00; Y10T428/29; Y10T428/2982; Y10T428/2991; Y10T428/2993; Y10T428/2995; Y10T428/2996; Y10T428/31504; Y10T428/31551; Y10T428/31609; Y10T428/31612
Claims Analysis
Total Claims: 24
Claim 1
Independent Claim
228 words
Hollow microspheres of 5 to 300 microns diameter with shells containing alkali metal silicate, a polysalt, an organosilicon compound multiply bonded within said silicate shell, said microspheres being characterized in that: (a) the ratio of polysalt solids to silicate solids is between 0.02:1 and 3.0:1, said polysalt being an inorganic salt of an alkali metal and/or ammonium cations wherein the anion to cation ratio is reduced when the salt is dissolved and becomes hydrolyzed and said alkali metal silicates having 1.5 to 4.0 moles of SiO 2 per mole of M 2 O wherein M is sodium or potassium; (b) the organosilicon constitutes 0.01 to 4.0% by weight of the microspheres, said organosilicon being the thermally and hydrolytically stable portion of an initial organosilicon compound having at least one thermally stable and non-hydrolyzable organic group and two or three reactive groups; (c) the ratio of true density to bulk density being between 1.2 and 1.9, the true density being 0.05 to 0.90 g/cm 3 and the bulk density being 0.05 to 0.24 g/cm 3 ; (d) the porosity (%P) of 5 to 10% as calculated by the formula ##EQU2## wherein ED is the effective density which has a value of 0.05 to 0.90 g/cm 3 and TD is the true density as recited in section (c) and 2.45 is the density of the wall in g/cm 3 .
Claim 2
Dependent Claim
228 words
Hollow microspheres of 5 to 300 microns diameter with shells containing alkali metal silicate, a polysalt, an organosilicon compound multiply bonded within said silicate shell, said microspheres being characterized in that: (a) the ratio of polysalt solids to silicate solids is between 0.02:1 and 3.0:1, said polysalt being an inorganic salt of an alkali metal and/or ammonium cations wherein the anion to cation ratio is reduced when the salt is dissolved and becomes hydrolyzed and said alkali metal silicates having 1.5 to 4.0 moles of SiO 2 per mole of M 2 O wherein M is sodium or potassium; (b) the organosilicon constitutes 0.01 to 4.0% by weight of the microspheres, said organosilicon being the thermally and hydrolytically stable portion of an initial organosilicon compound having at least one thermally stable and non-hydrolyzable organic group and two or three reactive groups; (c) the ratio of true density to bulk density being between 1.2 and 1.9, the true density being 0.05 to 0.90 g/cm 3 and the bulk density being 0.05 to 0.24 g/cm 3 ; (d) the porosity (%P) of 5 to 10% as calculated by the formula ##EQU2## wherein ED is the effective density which has a value of 0.05 to 0.90 g/cm 3 and TD is the true density as recited in section (c) and 2.45 is the density of the wall in g/cm 3 .
Claim 3
Dependent Claim
62 words
The hollow microspheres of claim 1 wherein said polysalt is ammonium pentaborate, the weight ratio of ammonium pentaborate solids to silicate solids being between 0.03:1 and 0.5:1, sodium pentaborate, the weight ratio of sodium pentaborate solids to silicate solids being between 0.02:1 and 0.3:1; or sodium hexametaphosphate, the weight ratio of sodium hexametaphosphate solids to silicate solids being between 1:1 and 3:1.
Claim 4
Dependent Claim
70 words
The hollow microspheres of claim 1 wherein the initial organosilicon compound is represented by the formula: R.sub.n SiX.sub.4-n where n=1 or 2, X represents H, Cl, Br, F or OR' wherein OR' is an alkoxy that provides a volatile product upon hydrolysis or thermal decomposition, and where R represents an alkyl, alkenyl or aryl group and their functional derivatives which remain thermally and hydrolytically stable and bound to the silicon.
Claim 5
Dependent Claim
8 words
The hollow microspheres of claim 3 wherein n=1.
Claim 6
Dependent Claim
32 words
The hollow microspheres of claim 1 wherein the initial organosilicon compound is represented by the formula R n Si--H 4-n wherein R is an aliphatic hydrocarbon and n is 1 or 2.
Claim 7
Dependent Claim
10 words
The hollow microspheres of claim 5 wherein R is methyl.
Claim 8
Dependent Claim
14 words
The hollow microspheres of claim 1 wherein the initial organosilicon compound is an organosilane.
Claim 9
Dependent Claim
17 words
The hollow microspheres of claim 7 wherein the organosilane is an alkylalkoxy silane or an arylalkoxy silane.
Claim 10
Dependent Claim
31 words
The hollow microspheres of claim 7 wherein the organosilane is selected from the group consisting of methyl-, ethyl-, propyl-, butyl-, vinyl- and phenyltriethoxysilane and methyl-, ethyl-, propyl-, butyl-, vinyl- and phenyl-tripropoxysilane.
Claim 11
Dependent Claim
11 words
The hollow microspheres of claim 7 wherein the organosilane is methyltrimethoxysilane.
Claim 12
Dependent Claim
22 words
The hollow microspheres of claim 1 wherein the weight ratio of ammonium pentaborate solids to silicate solids is between 0.06:1 and 0.5:1.
Claim 13
Dependent Claim
25 words
The hollow microspheres of either of claims 1 or 11 wherein said microspheres contain 10 to 17% by weight of moisture including chemically bound water.
Claim 14
Dependent Claim
25 words
The hollow microspheres of any of claims 1, or 6 wherein said microspheres contain 5 to 10% by weight of moisture including chemically bound water.
Claim 15
Dependent Claim
201 words
The process of preparing hollow microspheres of 5 to 300 microns diameter with shells containing alkali metal silicate and a polysalt, and an organosilicon compound multiply bonded within said silicate shell, comprising the steps of: (a) forming a homogeneous solution of 0.02 to 3.0 parts by weight of a polysalt for each part by weight of an alkali metal silicate, said "polysalt" being an inorganic salt of an alkali metal and/or ammonium cations wherein the anion to cation ratio is reduced when the salt is dissolved and becomes hydrolyzed, said alkali metal silicates having 1.5 to 4.0 moles of SiO 2 per mole of M 2 O, wherein M is sodium or potassium; (b) injecting said homogeneous polysalt-silicate solution into a spray dryer with an inlet temperature of about 150° to 500° C. and an outlet temperature of about 100° to 400° C., and simultaneously injecting into said spray dryer a liquid containing an organosilicon compound through a separate injection device in close proximity to the injection point for the homogeneous polysalt-silicate solution, said organosilicon compound having at least one thermally stable and non-hydrolyzable organic group and two or three reactive groups; and (c) recovering the product from the spray dryer.
Claim 16
Dependent Claim
201 words
The process of preparing hollow microspheres of 5 to 300 microns diameter with shells containing alkali metal silicate and a polysalt, and an organosilicon compound multiply bonded within said silicate shell, comprising the steps of: (a) forming a homogeneous solution of 0.02 to 3.0 parts by weight of a polysalt for each part by weight of an alkali metal silicate, said "polysalt" being an inorganic salt of an alkali metal and/or ammonium cations wherein the anion to cation ratio is reduced when the salt is dissolved and becomes hydrolyzed, said alkali metal silicates having 1.5 to 4.0 moles of SiO 2 per mole of M 2 O, wherein M is sodium or potassium; (b) injecting said homogeneous polysalt-silicate solution into a spray dryer with an inlet temperature of about 150° to 500° C. and an outlet temperature of about 100° to 400° C., and simultaneously injecting into said spray dryer a liquid containing an organosilicon compound through a separate injection device in close proximity to the injection point for the homogeneous polysalt-silicate solution, said organosilicon compound having at least one thermally stable and non-hydrolyzable organic group and two or three reactive groups; and (c) recovering the product from the spray dryer.
Claim 17
Dependent Claim
24 words
The process of claim 14 wherein the product recovered from the spray dryer is further dried slowly at temperatures between 70° and 400° C.
Claim 18
Dependent Claim
32 words
The process of either of claims 14 or 15 wherein the organosilicon compound is represented by the formulas: HSiMe.sub.2 O(MeSiHO).sub.n Me.sub.2 SiH; or HSiMe.sub.2 O(SiMe.sub.2 O).sub.n Me.sub.2 SiH; wherein n=2 to 20.
Claim 19
Dependent Claim
65 words
The process of either of claims 14 or 15 wherein said polysalt is ammonium pentaborate, the weight ratio of ammonium pentaborate solids to silicate solids being between 0.03:1 and 0.5:1; sodium pentaborate, the weight ratio of sodium pentaborate solids to silicate solids being between 0.02:1 and 0.3:1; or sodium hexametaphosphate, the weight ratio of sodium hexametaphosphate solids to silicate solids being between 1:1 and 3:1.
Claim 20
Dependent Claim
68 words
The process of claim 17 wherein the initial organosilicon compound is represented by the formula: R.sub.n SiX.sub.4-n where n=1 or 2, X represents Cl, Br, F or OR' wherein OR' is an alkoxy that provides a volatile product upon hydrolysis or thermal decomposition, and where R represents an alkyl, alkenyl or aryl group and their functional derivatives which remain thermally and hydrolytically stable and bound to the silicon.
Claim 21
Dependent Claim
40 words
The process of either of claims 14 or 15 wherein the organosilicon compound is an alkylalkoxysilane or an arylalkoxysilane selected from the group consisting of methyl-, ethyl-, propyl-, butyl-, vinyl- and phenyltriethoxysilane and methyl-, ethyl-, propyl-, butyl-, vinyl- and phenyl-tripropoxysilane.
Claim 22
Dependent Claim
10 words
The process of claim 19 wherein the alkylalkoxysilane is methyltrimethoxysilane.
Claim 23
Dependent Claim
30 words
The process of claims 14 or 18 wherein the organosilicon compound is represented by the formula R.sub.n Si--H.sub.4-n wherein R is an aliphatic hydrocarbon and n is 1 or 2.
Claim 24
Dependent Claim
9 words
The process of claim 21 wherein R is methyl.
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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) | 1988-09-09 | 1989-03-11 | 1989-09-10 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1992-09-09 | 1993-03-11 | 1993-09-10 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1996-09-09 | 1997-03-11 | 1997-09-10 | $7700.00 | Window Closed / Lapsed |