US3798013A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Double ion exchange method for strengthening glass articles
Assignee: Nippon Sheet Glass Co Ltd
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Filing: 1972-04-24
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Granted: 1974-03-19
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Expires: 1992-04-24
Abstract
Abstract A process for increasing the strength of a glass article by subjecting a glass article containing alkali metal ion A to a treatment of exchanging the ion A with an alkali metal ion B having a larger ion radius than the ion A, wherein the exchanging treatment is performed in two successive stages, and the secondstage exchanging treatment is carried out under milder treating conditions using a treating salt having a larger ion B content than in the first-stage treatment.
Inventors
- 👤 J Hasegawa
- 👤 T Inoue
- 👤 N Ohsato
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-09 04:24
CPC Classifications
C; C03; C03C; C03C21/00; C03C21/001; C03C21/002
Claims Analysis
Total Claims: 3
Claim 1
Independent Claim
22 words
The method of claim 1, wherein the treatment temperature is from 50*C. below the strain point to 100*C. below the strain point.
Claim 2
Dependent Claim
32 words
The method of claim 1, wherein the content of the alkali metal ion B is 60 to 80 mol percent based on the sum of the alkali metal ions A and B.
Claim 3
Dependent Claim
57 words
The method of claim 1, wherein the second-stage treatment is carried out in a plurality of stages wherein the proportion of the alkali metal ion B in one stage is equal to, or larger than, that in the preceding stage and also the ion-exchange reaction conditions in one stage are milder than those in the preceding stage.
References Cited (Backward Citations)
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1977-03-18 | 1977-09-17 | 1978-03-19 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1981-03-18 | 1981-09-17 | 1982-03-19 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1985-03-18 | 1985-09-17 | 1986-03-19 | $7700.00 | Window Closed / Lapsed |