Patent US4012541A successfully refreshed from Google Patents.
US4012541A
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US
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Method for wetting hydrophobic diaphragms for use in chlor-alkali cells
Assignee: BASF Corp
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Filing: 1975-10-01
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Granted: 1977-03-15
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Expires: 1995-10-01
Abstract
Abstract Hydrophobic diaphragm material, such as crystalline, highly expanded microporous polytetrafluoroethylene film, may be prepared for installation in a chlor-alkali cell by a process involving the steps of (1) immersing the diaphragm in a solution of acetal-type nonionic surfactant in a suitable non-aqueous solvent, (2) rinsing the diaphragm in deionized water, (3) immersing the diaphragm in an aqueous solution containing an amount of acetal-type nonionic surfactant effective to promote wetting for a suitable period of time, and (4) immersing the diaphragm in a brine solution containing about 100 to 200 grams per liter of sodium chloride and an amount effective to promote wetting of an acetal-type nonionic surfactant for a suitable period of time, such as several hours. In some instances, it is also advantageous to subject the diaphragm while immersed in the solvent solution to the action of a vacuum, to release trapped air.
Inventors
- 👤 Stanley T. Hirozawa
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-25 22:26
CPC Classifications
C; C25; C25B; C25B13/00; C25B13/04; C25B13/08
Claims Analysis
Total Claims: 30
Claim 1
Independent Claim
145 words
A method of preparing for use in a chlor-alkali cell a diaphragm of crystalline, highly expanded microporous polytetrafluoroethylene film, said method comprising the steps of immersing said diaphragm in a solution in a solvent selected from the group consisting of 2-propanol, n-propanol, ethanol and methanol, and containing an amount of an acetal-type nonionic surfactant effective to promote wetting of said diaphragm, rinsing said diaphragm in deionized water, immersing said diaphragm in an aqueous solution of an acetal-type nonionic surfactant under conditions of surfactant concentration and time effective to promote wetting of said diaphragm, and immersing said diaphragm in a solution of brine containing 100 to 200 grams per liter of sodium chloride and an amount effective to promote wetting of said diaphragm of acetal-type nonionic surfactant, for a period of time of at least three hours, and then installing said diaphragm in a chlor-alkali cell.
Claim 2
Independent Claim
145 words
A method of preparing for use in a chlor-alkali cell a diaphragm of crystalline, highly expanded microporous polytetrafluoroethylene film, said method comprising the steps of immersing said diaphragm in a solution in a solvent selected from the group consisting of 2-propanol, n-propanol, ethanol and methanol, and containing an amount of an acetal-type nonionic surfactant effective to promote wetting of said diaphragm, rinsing said diaphragm in deionized water, immersing said diaphragm in an aqueous solution of an acetal-type nonionic surfactant under conditions of surfactant concentration and time effective to promote wetting of said diaphragm, and immersing said diaphragm in a solution of brine containing 100 to 200 grams per liter of sodium chloride and an amount effective to promote wetting of said diaphragm of acetal-type nonionic surfactant, for a period of time of at least three hours, and then installing said diaphragm in a chlor-alkali cell.
Claim 3
Dependent Claim
20 words
A method as defined in claim 1, wherein said acetal-type nonionic surfactant is a C 8 to C 14 glycoside.
Claim 4
Dependent Claim
15 words
A method as defined in claim 2, wherein said acetal-type nonionic surfactant is decyl glycoside.
Claim 5
Dependent Claim
12 words
A method as defined in claim 1, wherein said solvent is 2-propanol.
Claim 6
Dependent Claim
20 words
A method as defined in claim 4, wherein said acetal-type nonionic surfactant is a C 8 to C 14 glycoside.
Claim 7
Dependent Claim
15 words
A method as defined in claim 5, wherein said acetal-type nonionic surfactant is decyl glycoside.
Claim 8
Dependent Claim
23 words
A method as defined in claim 1, characterized in that said solvent contains 0.005 to 0.5 weight percent of said acetal-type nonionic surfactant.
Claim 9
Dependent Claim
20 words
A method as defined in claim 7, wherein said acetal-type nonionic surfactant is a C 8 to C 14 glycoside.
Claim 10
Dependent Claim
15 words
A method as defined in claim 8, wherein said acetal-type nonionic surfactant is decyl glycoside.
Claim 11
Dependent Claim
12 words
A method as defined in claim 7, wherein said solvent is 2-propanol.
Claim 12
Dependent Claim
20 words
A method as defined in claim 10, wherein said acetal-type nonionic surfactant is a C 8 to C 14 glycoside.
Claim 13
Dependent Claim
15 words
A method as defined in claim 11, wherein said acetal-type nonionic surfactant is decyl glycoside.
Claim 14
Dependent Claim
49 words
A method as defined in claim 1, wherein the step of immersing said diaphragm in an aqueous solution of acetal-type nonionic surfactant is done in a solution containing 0.005 to 1.5 percent by weight of said surfactant for a period of time of from 5 minutes to 5 days.
Claim 15
Dependent Claim
20 words
A method as defined in claim 13, wherein said acetal-type nonionic surfactant is a C 8 to C 14 glycoside.
Claim 16
Dependent Claim
15 words
A method as defined in claim 14, wherein said acetal-type nonionic surfactant is decyl glycoside.
Claim 17
Dependent Claim
12 words
A method as defined in claim 13, wherein said solvent is 2-propanol.
Claim 18
Dependent Claim
20 words
A method as defined in claim 16, wherein said acetal-type nonionic surfactant is a C 8 to C 14 glycoside.
Claim 19
Dependent Claim
15 words
A method as defined in claim 17, wherein said acetal-type nonionic surfactant is decyl glycoside.
Claim 20
Dependent Claim
23 words
A method as defined in claim 13, characterized in that said solvent contains 0.005 to 0.5 weight percent of said acetal-type nonionic surfactant.
Claim 21
Dependent Claim
19 words
A method as defined in claim 19, wherein said acetal-type nonionic surfactant is C 8 to C 14 glycoside.
Claim 22
Dependent Claim
15 words
A method as defined in claim 20, wherein said acetal-type nonionic surfactant is decyl glycoside.
Claim 23
Dependent Claim
12 words
A method as defined in claim 19, wherein said solvent is 2-propanol.
Claim 24
Dependent Claim
19 words
A method as defined in claim 22, wherein said acetal-type nonionic surfactant is C 8 to C 14 glycoside.
Claim 25
Dependent Claim
15 words
A method as defined in claim 23, wherein said acetal-type nonionic surfactant is decyl glycoside.
Claim 26
Dependent Claim
23 words
A method as defined in claim 1, wherein said solution of brine contains 0.5 to 5 weight percent of said acetal-type nonionic surfactant.
Claim 27
Dependent Claim
20 words
A method as defined in claim 25, wherein said acetal-type nonionic surfactant is a C 8 to C 14 glycoside.
Claim 28
Dependent Claim
15 words
A method as defined in claim 26, wherein said acetal-type nonionic surfactant is decyl glycoside.
Claim 29
Dependent Claim
12 words
A method as defined in claim 27, wherein said solvent is 2-propanol.
Claim 30
Dependent Claim
23 words
A method as defined in claim 28, characterized in that said solvent contains 0.005 to 0.5 weight percent of said acetal-type nonionic surfactant.
References Cited (Backward Citations)
US2773114A
Cited
US3010536A
Cited
US3772269A
Cited
US3772072A
Cited
US3930979A
Cited
US3904496A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1980-03-14 | 1980-09-13 | 1981-03-15 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1984-03-14 | 1984-09-13 | 1985-03-15 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1988-03-14 | 1988-09-13 | 1989-03-15 | $7700.00 | Window Closed / Lapsed |