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US4547233A
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Gas-filled glass beads and method of making
Assignee: AGC Glass Europe SA
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Filing: 1984-05-09
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Granted: 1985-10-15
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Expires: 2004-05-09
Abstract
Abstract A method of producing gas filled hollow glass beads comprises the steps of: i. manufacturing hollow glass beads having an alkali content of at least 20% calculated as weight per cent of oxide in the bead, ii. exposing the beads to an acidic treatment medium, for example HCl, HNO 3 , H 2 SO 4 , SO 2 , SO 3 , to reduce the alkali content of the beads to not more than 15%, and iii. causing gas to diffuse into the beads.
Inventors
- 👤 Marcel Delzant
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-25 21:51
CPC Classifications
C; C03; C03C; C03C11/00; C03C11/002; C03B; C03B19/00; C03B19/10; C03B19/107; C03C15/00; C06; C06B; C06B23/00; C06B23/002; C06B23/003
Claims Analysis
Total Claims: 16
Claim 1
Independent Claim
80 words
A method of producing gas-filled hollow glass beads comprising the steps of manufacturing hollow glass beads having an alkali content of at least 20% calculated as weight % of oxide in the bead, contacting the beads with an acidic treatment medium to reduce the alkali content of the beads to not more than 15%, and causing nonhydrogen gas to diffuse into the beads after manufacture thereof by exposing said beads to said gas at a pressure greater than one atmosphere.
Claim 2
Independent Claim
80 words
A method of producing gas-filled hollow glass beads comprising the steps of manufacturing hollow glass beads having an alkali content of at least 20% calculated as weight % of oxide in the bead, contacting the beads with an acidic treatment medium to reduce the alkali content of the beads to not more than 15%, and causing nonhydrogen gas to diffuse into the beads after manufacture thereof by exposing said beads to said gas at a pressure greater than one atmosphere.
Claim 3
Dependent Claim
25 words
A method according to claim 1, wherein the gas caused to diffuse into the beads is at least one of nitrogen, krypton, argon and helium.
Claim 4
Dependent Claim
39 words
A method according to claim 1, wherein said step of causing gas to diffuse comprises placing the beads in an environment at a temperature in the range 200° to 550° C. and a pressure of at least 5 bar.
Claim 5
Dependent Claim
19 words
A method according to claim 1 wherein said diffusion takes place substantially in the absence of H 2 O.
Claim 6
Dependent Claim
30 words
A method according to claim 1 wherein said acidic treatment medium is selected from among HCl, HNO 3 , H 2 SO 4 , SO 2 and SO 3 .
Claim 7
Dependent Claim
35 words
A method according to claim 1 wherein at the commencement of reduction of bead alkali during said step of contacting, the acidic treatment medium is an aqueous solution having a pH of at least 2.5.
Claim 8
Dependent Claim
39 words
A method according to claim 1 further comprising treating the beads with a polishing solution containing an organic acid selected from among beta-hydroxy acids, oxalic acid and ethylene diamine tetracetic acid and/or a salt of a said organic acid.
Claim 9
Dependent Claim
20 words
A method according to claim 7 wherein the organic acid is a beta-hydroxy acid which is also an alpha-hydroxy acid.
Claim 10
Dependent Claim
32 words
A method according to claim 7 wherein at the beginning of said treating step, said solution has a pH of at least 5 and preferably in the range 7 to 10 inclusive.
Claim 11
Dependent Claim
19 words
A method according to claim 7 wherein said steps of contacting and treating take place during overlapping time periods.
Claim 12
Dependent Claim
20 words
A method according to claim 1 further comprising, after said contacting step, bringing said beads in contact with an organo-silane.
Claim 13
Dependent Claim
10 words
Glass beads produced by the method according to claim 1.
Claim 14
Dependent Claim
11 words
An emulsion-type explosive composition incorporating glass beads according to claim 12.
Claim 15
Dependent Claim
33 words
A method according to claim 1, wherein said step of causing gas to diffuse is conducted so that said beads are charged with said gas to pressure of at least about one bar.
Claim 16
Dependent Claim
58 words
A method according to claim 1, wherein the gas caused to diffuse into the beads is at least one of nitrogen, krypton, argon and helium, and wherein said step of causing gas to diffuse comprises placing the beads in an environment at a temperature in the range 200° to 550° and a pressure of at least 5 bar.
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USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1988-10-14 | 1989-04-15 | 1989-10-15 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1992-10-14 | 1993-04-15 | 1993-10-15 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1996-10-14 | 1997-04-15 | 1997-10-15 | $7700.00 | Window Closed / Lapsed |