US3710945A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Preservation of polyamidic membranes
Assignee: EIDP Inc
•
Filing: 1969-11-26
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Granted: 1973-01-16
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Expires: 1989-11-26
Abstract
Abstract Selectively permeable, polymeric membranes for use in the reverse osmosis separation of components of aqueous mixtures and solutions, particularly saline and brackish water, are chemically treated to preserve their permeability characteristics and to protect against loss thereof during the obtention of a watertight seal with the potting compounds generally employed in permeation separation devices. The desired results are achieved by effecting a substantial replacement of membrane-associated water with an inert organic medium exhibiting a lower volatility than water. Depending on the degree of hydrophilicity and water solubility of the organic medium, replacement of the membrane-associated water is accomplished by direct contact including successive contacts of the water-wet membrane with aqueous solutions of increasing organic medium concentration and/or indirect contact including successive contacts of the membrane with organic media of decreasing hydrophilicity. Reversal of the replacement process to reintroduce water to the membrane structure restores the operability of the members and renders them effective for their intended desalination and purification functions.
Inventors
- 👤 P Dismore
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-26 06:56
CPC Classifications
B; B01; B01D; B01D67/00; B01D67/0081; B01D67/0088; B01D63/00; B01D63/02; B01D63/021; B01D63/022; B01D67/0097; B01D71/00; B01D71/06; B01D71/56; Y; Y02; Y02A; Y02A20/00; Y02A20/124; Y02A20/131
Claims Analysis
Total Claims: 30
Claim 1
Independent Claim
10 words
A membrane according to claim 1 comprising an aliphatic polyamide.
Claim 2
Dependent Claim
66 words
A membrane according to claim 2 wherein said aliphatic polyamide is characterized by at least one recurring group in the polymer chain selected from where R, R1 and R2 divalent aliphatic radicals X, X1 and X2 hydrogen atoms or monovalent saturated aliphatic hydrocarbon radicals containing one to about four carbon atoms, the number of hydrogen atoms being at least about one-half the number of hydrocarbon radicals.
Claim 3
Dependent Claim
22 words
A membrane according to claim 3 wherein said aliphatic polyamide is the homopolymerization product of an aliphatic monoaminocarboxylic acid or derivative thereof.
Claim 4
Dependent Claim
23 words
A membrane according to claim 3 wherein said aliphatic polyamide is the condensation product of an aliphatic diamine and an aliphatic dicarboxylic acid.
Claim 5
Dependent Claim
21 words
A membrane according to claim 5 wherein said aliphatic diamine is hexamethylene diamine and said aliphatic dicarboxylic acid is adipic acid.
Claim 6
Dependent Claim
10 words
A membrane according to claim 1 comprising an aromatic polyamide.
Claim 7
Dependent Claim
58 words
A membrane according to claim 7 wherein said aromatic polyamide is characterized by the following recurring group in the polymer chain where Ar1 and Ar2 substituted or unsubstituted divalent aromatic radicals wherein the chain-extending bonds are oriented meta or para to each other and any substituents attached to the aromatic nucleus are not condensed with reactants during polymerization.
Claim 8
Dependent Claim
23 words
A membrane according to claim 8 wherein said aromatic polyamide is the condensation product of an aromatic diamine and an aromatic diacid halide.
Claim 9
Dependent Claim
26 words
A membrane according to claim 8 wherein said aromatic polyamide is the condensation product of meta phenylene diamine and a mixture of isophthaloyl and terephthaloyl chlorides.
Claim 10
Dependent Claim
9 words
A membrane according to claim 1 comprising a polyhydrazide.
Claim 11
Dependent Claim
50 words
A membrane according to claim 11 wherein said polyhydrazide is characterized by the following recurring structural unit where Ar a divalent aromatic radical having at least three nuclear atoms between points of attachment; at least 35 mol percent of the aromatic radicals in any polyhydrazide being other than para-phenylene radicals.
Claim 12
Dependent Claim
20 words
A membrane according to claim 12 wherein said polyhydrazide is the condensation product of hydrazine and an aromatic diacid chloride.
Claim 13
Dependent Claim
22 words
A membrane according to claim 12 wherein said polyhydrazide is the condensation product of an aromatic dihydrazide and an aromatic diacid chloride.
Claim 14
Dependent Claim
34 words
A membrane according to claim 14 wherein said aromatic dihydrazide is a mixture of isophthalic dihydrazide and ethylene bis-4-benzoyl hydrazide and said aromatic diacid chloride is a mixture of isophthaloyl chloride and terephthaloyl chloride.
Claim 15
Dependent Claim
9 words
A membrane according to claim 1 comprising a poly(amide-hydrazidE).
Claim 16
Dependent Claim
25 words
A membrane according to claim 16 wherein said poly(amide-hydrazide) is the condensation product of at least one diacid chloride, an aromatic amine and a hydrazide.
Claim 17
Dependent Claim
34 words
A membrane according to claim 16 wherein said poly(amide-hydrazide) is the condensation product of a mixture of 50-90 percent by weight of isophthaloyl chloride, balance terephthaloyl chloride and m-phenylene diamine and an aromatic dihydrazide.
Claim 18
Dependent Claim
21 words
A membrane according to claim 1 wherein said inert organic medium is hydrophilic and has a boiling point higher than 180*C.
Claim 19
Dependent Claim
21 words
A membrane according to claim 1 wherein said inert organic medium is hydrophobic and has a boiling point higher than 180*C.
Claim 20
Dependent Claim
13 words
A membrane according to claim 1 wherein said inert organic medium is glycerine.
Claim 21
Dependent Claim
14 words
A membrane according to claim 1 wherein said inert organic medium is paraffin wax.
Claim 22
Dependent Claim
13 words
A membrane according to claim 1 wherein said inert organic medium is naphthalene.
Claim 23
Dependent Claim
18 words
A membrane according to claim 1 wherein said inert organic medium is a mixture of camphor and naphthalene.
Claim 24
Dependent Claim
14 words
A membrane according to claim 1 wherein said inert organic medium is polyethylene glycol.
Claim 25
Dependent Claim
13 words
A membrane according to claim 1 in the form of a flat film.
Claim 26
Dependent Claim
13 words
A membrane according to claim 1 in the form of a hollow fiber.
Claim 27
Independent Claim
54 words
A method of preserving operational characteristics of selectively permeable, highly hydrophilic substituted, polymeric polyamide membranes adapted for use in combination with apparatus for the reverse osmosis separation of components of aqueous mixtures, said method comprising substantially replacing membrane-associated water with an inert organic medium less volatile than water and capable of wetting said membranes.
Claim 28
Dependent Claim
36 words
A method according to claim 28 wherein replacement of membrane-associated water is effected by contacting the highly hydrophilic substituted membranes with an aqueous solution of a hydrophilic organic medium having a boiling point higher than 180*C.
Claim 29
Dependent Claim
117 words
A selectively permeable, polymeric polyamide membrane adapted for use in combination with apparatus for the reverse osmosis separation of components of aqueous mixtures when highly substituted and characterized by improved preservation of operational characteristics, said membrane being highly substituted with an inert organic medium less volatile than water and capable of wetting said membrane, the membrane being further characterized by improved protection against loss of operational characteristics during sealing with hydrophobic potting compounds employed in said apparatus and having a hollow fiber configuration comprising an active length and a potting area, said active length being highly substituted with said inert organic medium and said potting area being substantially free from said inert organic medium and from water.
Claim 30
Independent Claim
95 words
A method of preserving operational characteristics of selectively permeable, highly hydrophilic substituted, polymeric polyamide membranes having a hollow fiber configuration and adapted for use in combination with apparatus for the reverse osmosis separation of components of aqueous mixtures, said method comprising substantially replacing membrane-associated water with an inert organic medium less volatile than water and capable of wetting said membranes and thereafter substantially removing said organic replacement medium from the potting areas of preserved membranes and drying said areas to promote the sealing capability of said membranes with hydrophobic potting compounds employed in said apparatus.
References Cited (Backward Citations)
US1057823A
Cited
US3423491A
Cited
US3565259A
Cited
US3567632A
Cited
US3546209A
Cited
US3551331A
Cited
US3592672A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1976-01-16 | 1976-07-17 | 1977-01-16 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1980-01-16 | 1980-07-17 | 1981-01-16 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1984-01-16 | 1984-07-17 | 1985-01-16 | $7700.00 | Window Closed / Lapsed |