Patent US4767726A successfully refreshed from Google Patents.
US4767726A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Glass microbubbles
Assignee: 3M Co
•
Filing: 1987-01-12
•
Granted: 1988-08-30
•
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 09:25
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.
References Cited (Backward Citations)
US2978340A
Cited
US3030215A
Cited
US3129086A
Cited
US3230064A
Cited
US3365315A
Cited
JPS4937565A
Cited
US4391646A
Cited
EP0165875A1
Cited
US4661137A
Cited
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 |