US3615319A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Ion exchange strengthening of glasses with lithium vapor
Assignee: Anchor Hocking LLC
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Filing: 1967-12-11
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Granted: 1971-10-26
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Expires: 1987-12-11
Abstract
Abstract Soda-lime glass articles are strengthened by exposure to vapors of certain lithium compounds while heated to or above the annealing point. Exposure at temperatures below the annealing point is avoided, to prevent etching the glass surface. Lithium ions migrate into a zone of the glassy network underlying the exposed surface and partially replace alkali metal ions therein. Upon cooling, the lithium-enriched shell is placed in compression about the glass article. Strength improvements are achieved in short periods of time.
Inventors
- 👤 Francis J Shonebarger
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-29 02:36
CPC Classifications
C; C03; C03C; C03C21/00; C03C21/007
Claims Analysis
Total Claims: 10
Claim 1
Independent Claim
18 words
The method of claim 1 wherein said exposure is for a period between 1 minute and 1 hour.
Claim 2
Dependent Claim
25 words
The method of claim 1 wherein said exposure is carried out by placing a supply of said compound adjacent to said article in a furnace.
Claim 3
Dependent Claim
23 words
The method of claim 1 wherein said exposure is carried out at temperatures corresponding to glass viscosities of about 1010.0 to 1012.6 poises.
Claim 4
Dependent Claim
22 words
The method of claim 1 wherein said exposure is carried out at temperatures corresponding to glass viscosities of 1010.6 to 1011.7 poises.
Claim 5
Dependent Claim
30 words
The method of claim 1 wherein said composition is a soda-lime glass composition comprising about 65-74 percent SiO2, 14-17 percent Na2O, 7-12 percent (MgO+CaO), and up to 3 percent Al2O3.
Claim 6
Dependent Claim
24 words
The method of claim 1 wherein said exposure is carried out at a temperature of 25*-150* F. above the annealing point of said article.
Claim 7
Independent Claim
201 words
A method for making a strengthened glass article comprising, first, melting a batch of glass-making ingredients so as to provide a glass batch having on an oxide basis about 65-74 percent SiO2, 14-17 percent Na2O, 7-12 percent (MgO+CaO) and up to 3 percent Al2O3, forming at least one article from said glass batch, introducing said article into a treating chamber and heating it therein to a temperature above its annealing point but below the temperature at which the article sags out of desired shape, in the absence of substantial amounts of lithium treating vapor, subsequently introducing into said chamber, while said article is at said temperature, a vapor of at least one lithium compound selected from the class consisting of LiBr, LiCl, LiF, LiI, LiNH2 in the absence of water, and Li2SO4, and exposing at least a portion of the surface of said article to said vapor in said chamber at said temperature for a period of time between 1 minute and 1 hour sufficient to replace a portion of the alkali metal ions with lithium ions, terminating the exposure of said article to said vapor, then cooling said article from said temperature to room temperature in the absence of vapor.
Claim 8
Dependent Claim
19 words
The method of claim 8 wherein a supply of said compound is placed in the chamber adjacent said article.
Claim 9
Dependent Claim
21 words
The method of claim 9 wherein said supply is removed from said chamber before said article is cooled from said temperature.
Claim 10
Dependent Claim
29 words
The method of claim 9 wherein said supply is preheated to the temperature at which said article is to be exposed, before said source is placed in said chamber.
References Cited (Backward Citations)
GB748820A
Cited
US2779136A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1974-10-25 | 1975-04-26 | 1975-10-26 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1978-10-25 | 1979-04-26 | 1979-10-26 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1982-10-25 | 1983-04-26 | 1983-10-26 | $7700.00 | Window Closed / Lapsed |