US4172931A
Expired / Lapsed
US
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Welding of membranes of fluorinated polymers
Assignee: BASF SE
•
Filing: 1977-11-15
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Granted: 1979-10-30
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Expires: 1997-11-15
Abstract
Abstract A process for welding membranes of fluorinated polymers which contain groups with exchangeable H-ions. To carry out the process, the polymer in at least one of the membranes to be welded together must be in the H-form.
Inventors
- 👤 Bernd Leutner
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-29 20:55
CPC Classifications
B; B01; B01D; B01D71/00; B01D71/06; B01D71/30; B01D71/32; C; C08; C08J; C08J5/00; C08J5/12; C08J5/121; C08J5/20; C08J5/22; C08J5/2287; C08J5/2293; C08J2327/00; C08J2327/02; C08J2327/12; C08J2327/18
Claims Analysis
Total Claims: 9
Claim 1
Independent Claim
62 words
A process for welding together membranes of fluorinated polymers containing exchangeable cations which comprises treating a membrane to be welded with a mineral acid to convert the exchangeable cations predominantly to the H-form, and heating the membranes to be welded to a temperature of from about 200° to 350° C. in a press under a pressure of from 1 to 100 bars.
Claim 2
Dependent Claim
62 words
A process for welding together membranes of fluorinated polymers containing exchangeable cations which comprises treating a membrane to be welded with a mineral acid to convert the exchangeable cations predominantly to the H-form, and heating the membranes to be welded to a temperature of from about 200° to 350° C. in a press under a pressure of from 1 to 100 bars.
Claim 3
Dependent Claim
16 words
A process as set forth in claim 1, wherein the fluorinated polymers contain sulfonic acid groups.
Claim 4
Dependent Claim
32 words
A process as set forth in claim 1, wherein the welding is carried out at from 230° to 280° C. in a press under a pressure of from 1.5 to 20 bars.
Claim 5
Dependent Claim
33 words
A process as set forth in claim 1 wherein the exchangeable cations are selected from the group consisting of --SO 3 X, --COOX or PO 3 X, wherein X is an alkali metal.
Claim 6
Dependent Claim
26 words
A process as set forth in claim 1, wherein the polymer in the H-form has from 50 to 100% of the exchangeable groups in this form.
Claim 7
Dependent Claim
18 words
A process as set forth in claim 1, wherein the membranes are from 10 to 2,000 μm thick.
Claim 8
Dependent Claim
44 words
A process as set forth in claim 1, wherein the polymers are converted to the H-form by treatment with hydrochloric acid or nitric acid at a temperature of from room temperature to the boiling point of the acid for from 0.1 to 20 hours.
Claim 9
Dependent Claim
20 words
A process as set forth in claim 7, wherein the membrane after treatment with acid is washed and air dried.
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) | 1982-10-29 | 1983-04-30 | 1983-10-30 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1986-10-29 | 1987-04-30 | 1987-10-30 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1990-10-29 | 1991-04-30 | 1991-10-30 | $7700.00 | Window Closed / Lapsed |