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US4023951A
Expired / Lapsed
US
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Treatment of glass
Assignee: Imperial Chemical Industries Ltd
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Filing: 1975-08-25
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Granted: 1977-05-17
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Expires: 1995-08-25
Abstract
Abstract A process for strengthening or toughening a phosphate glass the process comprising contacting the surface of the phosphate glass with a solution of a carboxylic acid in a liquid diluent, the carboxylic acid comprising an amino-carboxylic acid, or a hydroxy-carboxylic acid, or a mixture of an amino-carboxylic acid and a hydroxy-carboxylic acid. Particularly useful is an aqueous solution of an amino-polycarboxylic acid.
Inventors
- 👤 Bryan Shaw
- 👤 Neil Winterton
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-26 17:46
CPC Classifications
C; C03; C03C; C03C3/00; C03C3/12; C03C3/16; C03C3/19; C03C23/00
Claims Analysis
Total Claims: 11
Claim 1
Independent Claim
93 words
A process for the strengthening of a phosphate glass which contains at least 50 mole % P 2 O 5 , which process comprises contacting a surface of a phosphate glass with a solution of 0.05 to 1.0 mole per liter of a carboxylic acid in a liquid diluent at a temperature in the range of 0° to 100° C, the solution having a pH in the range 4 to 12, the carboxylic acid comprising an amino-carboxylic acid, or a hydroxy-carboxylic acid, or a mixture of an amino-carboxylic acid and a hydroxy-carboxylic acid.
Claim 2
Dependent Claim
93 words
A process for the strengthening of a phosphate glass which contains at least 50 mole % P 2 O 5 , which process comprises contacting a surface of a phosphate glass with a solution of 0.05 to 1.0 mole per liter of a carboxylic acid in a liquid diluent at a temperature in the range of 0° to 100° C, the solution having a pH in the range 4 to 12, the carboxylic acid comprising an amino-carboxylic acid, or a hydroxy-carboxylic acid, or a mixture of an amino-carboxylic acid and a hydroxy-carboxylic acid.
Claim 3
Dependent Claim
16 words
A process as claimed in claim 1 in which the carboxylic acid comprises a polycarboxylic acid.
Claim 4
Dependent Claim
25 words
A process as claimed in claim 2 in which the surface of a phosphate glass is contacted with a solution of an amino polycarboxylic acid.
Claim 5
Dependent Claim
22 words
A process as claimed in claim 1 in which the phosphate glass is contacted with an aqueous solution of a carboxylic acid.
Claim 6
Dependent Claim
20 words
A process as claimed in claim 1 in which the solution has a pH in the range 5 to 10.
Claim 7
Dependent Claim
22 words
A process as claimed in claim 1 in which the temperature of the solution is in the range 20° to 80° C.
Claim 8
Dependent Claim
24 words
A process as claimed in claim 1 in which the phosphate glass contains at least 60 mole % of P 2 O 5 .
Claim 9
Dependent Claim
61 words
A process as claimed in claim 1 in which the phosphate glass has a composition (in mole %) P 2 o 5 50 to 72 B 2 o 3 1.2 to 3.5 PbO 0 to 30 transition metal oxide 0 to 5 oxide or oxides selected from alkali metal oxides, alkaline earth metal oxides and zinc oxide 2 to 40 .
Claim 10
Dependent Claim
37 words
A process as claimed in claim 1 in which carboxylic acid is ethylene diamine tetra-acetic acid, nitrilotriacetic acid, a disodium salt of ethylene diamine tetra-acetic acid, p-phenylene diamine N,N,N',N' tetra-acetic acid, citric acid, tartaric acid, or glycine.
Claim 11
Dependent Claim
18 words
A process as claimed in claim 1 in which the glass is in the form of a lens.
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) | 1980-05-16 | 1980-11-15 | 1981-05-17 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1984-05-16 | 1984-11-15 | 1985-05-17 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1988-05-16 | 1988-11-15 | 1989-05-17 | $7700.00 | Window Closed / Lapsed |