Patent US3785793A successfully refreshed from Google Patents.
US3785793A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Method of leaching high silica glass having 0.5-2.0% p2o5
Assignee: National Industrial Research Institute
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Filing: 1972-05-26
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Granted: 1974-01-15
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Expires: 1992-05-26
Abstract
Abstract The addition of small controlled amounts of P2O5 to a borosilicate glass improves the speed and homogenity of phase separation upon heating of the glass. A borosilicate glass of the formula 65-75 percent SiO2, 15-25% B2O3, 5-10% R2O and 0.5-2.0% P2O5, wherein R is Na, K or Li, is heated and undergoes phase separation into a silica rich phase and an acid soluble R2O B2O3 - P2O5 phase. The acid soluble phase is leached with acid to form a porous high silica glass which can be reheated at about 1,200*C to contract the glass thereby yielding a transparent nonporous glass of properties similar to quartz glass.
Inventors
- 👤 Y Park
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-05 19:00
CPC Classifications
C; C03; C03C; C03C15/00; C03C11/00; C03C11/005; C03C3/00; C03C3/04; C03C3/076; C03C3/097
Claims Analysis
Total Claims: 6
Claim 1
Independent Claim
19 words
leaching out the acid soluble R2O - B2O3 - P2O5 glass phase to form a porous high silica glass.
Claim 2
Dependent Claim
21 words
The process of claim 1 wherein the porous high silica glass is reheated at a temperature sufficient to contract the glass.
Claim 3
Dependent Claim
13 words
The process of claim 2 wherein the temperature of reheating is about 1,200*C.
Claim 4
Dependent Claim
19 words
The process of claim 1 wherein the amount of P2O5 added is in the range 0.57 - 1.69 percent.
Claim 5
Dependent Claim
29 words
The process of claim 1 wherein the borosilicate glass comprises 65-75 percent SiO2, 15 to 25 percent B2O3, 5 to 10 percent R2O and 0.5 to 2.0 percent P2O5.
Claim 6
Dependent Claim
21 words
The process of claim 5 wherein the porous high silica glass is reheated at a temperature sufficient to contract the glass.
References Cited (Backward Citations)
No citation records indexed.
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1977-01-14 | 1977-07-16 | 1978-01-15 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1981-01-14 | 1981-07-16 | 1982-01-15 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1985-01-14 | 1985-07-16 | 1986-01-15 | $7700.00 | Window Closed / Lapsed |