US4767726A
Expired / Lapsed
US
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Glass microbubbles
Assignee: 3M Co
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Filing: 1987-01-12
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Granted: 1988-08-30
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Expires: 2007-01-12
Abstract
Abstract Glass microbubbles having, on a weight basis, a composition consisting essentially of 70-80% SiO 2 , 8-15% CaO, 3-8% Na 2 O, and 2-6% B 2 O 3 , and about 0.2-1.5% SO 3 and having a CaO:Na 2 O ratio of 1-3.5. These microbubbles, which are made of significantly less expensive raw materials than conventional products, can also be made with a higher percent "floaters" and a lower average density. Certain substitutions can be made for at least a portion of each of the first three oxides.
Inventors
- 👤 Harry J. Marshall
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-04 05:07
CPC Classifications
C; C03; C03C; C03C11/00; C03C11/002
Claims Analysis
Total Claims: 21
Claim 1
Independent Claim
45 words
Microbubbles of glass having an alkaline earth metal oxide:alkali metal oxide weight ratio in the range of 1.2:1-3.0:1; at least 97% of the glass weight consisting essentially of 70-80% SiO 2 , 8-15% CaO, 3-8% Na 2 O, and 2-6% B 2 O 3 .
Claim 2
Dependent Claim
45 words
Microbubbles of glass having an alkaline earth metal oxide:alkali metal oxide weight ratio in the range of 1.2:1-3.0:1; at least 97% of the glass weight consisting essentially of 70-80% SiO 2 , 8-15% CaO, 3-8% Na 2 O, and 2-6% B 2 O 3 .
Claim 3
Dependent Claim
19 words
The microbubbles of claim 1 wherein the density of the microbubbles is in the range of 0.08 to 0.8.
Claim 4
Dependent Claim
17 words
The microbubbles of claim 1 wherein the CaO:Na 2 O ratio is in the range of 1.2:1-3.0:1.
Claim 5
Dependent Claim
15 words
The microbubbles of claim 3 wherein the CaO:Na 2 O ratio is at least 1.9:1.
Claim 6
Dependent Claim
19 words
A free-flowing mass of glass particles, at least 70% by weight of which are the microbubbles of claim 2.
Claim 7
Dependent Claim
53 words
Microbubbles of glass having an alkaline earth metal oxide:alkali metal oxide weight ratio in the range of 1.2:1-3.0:1, and a density in the range of 0.08-0.8, at least 90% of the glass weight consisting essentially of 70-80% SiO 2 , 8-15% CaO, 3-8% Na 2 O, and 2-6% B 2 O 3 .
Claim 8
Dependent Claim
53 words
Microbubbles of glass having an alkaline earth metal oxide:alkali metal oxide weight ratio in the range of 1.2:1-3.0:1, and a density in the range of 0.08-0.8, at least 90% of the glass weight consisting essentially of 70-80% SiO 2 , 8-15% CaO, 3-8% Na 2 O, and 2-6% B 2 O 3 .
Claim 9
Dependent Claim
20 words
A free flowing mass of glass particles, at least 70% by weight of which are the microbubbles of claim 6.
Claim 10
Dependent Claim
22 words
The glass particles of claim 7 wherein the alkaline earth metal oxide:alkali metal oxide ratio of the microbubbles is at least 1.9:1.
Claim 11
Dependent Claim
22 words
The microbubbles of claim 1 wherein the glass contains up to about 1.0% P 2 O 5 and/or 1.0% Li 2 O.
Claim 12
Dependent Claim
16 words
The microbubbles of claim 9 wherein the glass contains up to about 1.5% SO 3 .
Claim 13
Dependent Claim
56 words
Microbubbles of glass having an alkaline earth metal oxide:alkali metal oxide weight ratio in the range of 1.2:1-3.0:1, at least 90% of the glass weight consisting essentially of 70-80% SiO 2 , 8-15% RO, 3-8% R 2 O, and 2-6% B 2 O 3 , wherein R is at least one metal having the indicated valence.
Claim 14
Dependent Claim
56 words
Microbubbles of glass having an alkaline earth metal oxide:alkali metal oxide weight ratio in the range of 1.2:1-3.0:1, at least 90% of the glass weight consisting essentially of 70-80% SiO 2 , 8-15% RO, 3-8% R 2 O, and 2-6% B 2 O 3 , wherein R is at least one metal having the indicated valence.
Claim 15
Dependent Claim
19 words
The microbubbles of claim 11 wherein the alkaline earth metal oxide:alkali metal oxide weight ratio is at least 1.9:1.
Claim 16
Dependent Claim
44 words
The microbubbles of claim 11 wherein at least 97% of the glass weight consists essentially of 70-80% SiO 2 , 8-15% RO, 3-8% R 2 O, and 2-6% B 2 O 3 , wherein R is at least one metal having the indicated valence.
Claim 17
Dependent Claim
19 words
The microbubbles of claim 13 wherein the alkaline earth metal oxide:alkali metal oxide weight ratio is at least 1.9.
Claim 18
Dependent Claim
19 words
A free-flowing mass of glass particles, at least 70% by weight of which are the microbubbles of claim 11.
Claim 19
Dependent Claim
19 words
A free-flowing mass of glass particles, at least 70% by weight of which are the microbubbles of claim 12.
Claim 20
Dependent Claim
19 words
A free-flowing mass of glass particles, at least 70% by weight of which are the microbubbles of claim 13.
Claim 21
Dependent Claim
19 words
A free-flowing mass of glass particles, at least 70% by weight of which are the microbubbles of claim 14.
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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) | 1991-08-30 | 1992-02-29 | 1992-08-30 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1995-08-30 | 1996-02-29 | 1996-08-30 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1999-08-30 | 2000-02-29 | 2000-08-30 | $7700.00 | Window Closed / Lapsed |