US3951815A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Composite semipermeable membranes made from polyethylenimine
Assignee: Universal Oil Products Co
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Filing: 1974-09-05
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Granted: 1976-04-20
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Expires: 1994-09-05
Abstract
Abstract Composite semipermeable membranes are made by reacting a film-forming polymer with a cross-linking monomer to form a polymeric ultrathin film having semipermeable properties. During the formation, a grafting reaction is carried out at reactive sites so there are few remaining active sites where oxidizing attack or fouling can potentially occur. One composite membrane comprises a microporous substrate and an ultrathin polyamide film formed of polyethylenimine cross-linked with a monomer, such as an acyl halide, a chloroformate, an isocyanate or a sulfonyl chloride. Grafted onto the cross-linked polyethylenimine at what would otherwise be secondary amido sites is an epoxide, an aldehyde, an anhydride or a reactive ethylene compound.
Inventors
- 👤 Wolfgang J. Wrasidlo
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-24 05:18
CPC Classifications
C; C08; C08G; C08G73/00; C08G73/02; C08G73/0206; C08G73/0213; C08G73/022; B; B01; B01D; B01D69/00; B01D69/12; B01D69/125; B01D71/00; B01D71/06; B01D71/58; B01D71/60
Claims Analysis
Total Claims: 16
Claim 1
Independent Claim
89 words
A composite semipermeable membrane which comprises a microporous substrate and an ultrathin film formed of a crosslinked, grafted polyethylenimine having semipermeable properties disposed on one surface of said microporous substrate, said ultrathin film being formed of polyethylenimine that has been cross-linked with a di- or tri-functional compound selected from the group consisting of acyl halides, chloroformates, isocyanates and sulfonyl chlorides, said crosslinked polyethylenimine also having grafted thereonto, at what would otherwise be secondary amido sites, a graft reactant selected from the group consisting of acrylonitrile, epichlorohydrin and phthalic anhydride.
Claim 2
Dependent Claim
89 words
A composite semipermeable membrane which comprises a microporous substrate and an ultrathin film formed of a crosslinked, grafted polyethylenimine having semipermeable properties disposed on one surface of said microporous substrate, said ultrathin film being formed of polyethylenimine that has been cross-linked with a di- or tri-functional compound selected from the group consisting of acyl halides, chloroformates, isocyanates and sulfonyl chlorides, said crosslinked polyethylenimine also having grafted thereonto, at what would otherwise be secondary amido sites, a graft reactant selected from the group consisting of acrylonitrile, epichlorohydrin and phthalic anhydride.
Claim 3
Dependent Claim
18 words
A membrane in accordance with claim 1 wherein said crosslinking compound is a diacyl or triacyl aromatic halide.
Claim 4
Dependent Claim
17 words
A membrane in accordance with claim 1 wherein said cross-linking compound is isophthaloyl chloride or terephtaloyl chloride.
Claim 5
Dependent Claim
13 words
A membrane in accordance with claim 3 wherein said graft reactant is acrylonitrile.
Claim 6
Dependent Claim
14 words
A membrane in accordance with claim 4 wherein said cross-linking compound is isophthaloyl chloride.
Claim 7
Dependent Claim
13 words
A membrane in accordance with claim 3 wherein said graft reactant is epichlorohydrin.
Claim 8
Dependent Claim
21 words
A composite semipermeable membrane in accordance with claim 1 wherein said ultrathin film has a thickness of at least about 250°A.
Claim 9
Dependent Claim
29 words
A composite semipermeable membrane in accordance with claim 3 wherein said polyethylenimine contains at least about 15 percent of its aninoethylene moieties as branches to the main molecular chain.
Claim 10
Dependent Claim
19 words
A membrane in accordance with claim 8 wherein said polyethylenimine has a molecular weight between about 40,000 and 60,000.
Claim 11
Dependent Claim
70 words
A composite semipermeable membrane which comprises a microporous substrate and an ultrathin film at least about 250°A thick formed of a crosslinked, grafted polyethylenimine having semipermeable properties disposed on one surface of said microporous substrate, said ultrathin film being formed of polyethylenimine that has been crosslinked with isophthaloyl chloride or terephtaloyl chloride, said crosslinked polyethylenimine also having acrylonitrile or epichlorohydrin grafted thereonto, at what would otherwise be secondary amido sites.
Claim 12
Dependent Claim
70 words
A composite semipermeable membrane which comprises a microporous substrate and an ultrathin film at least about 250°A thick formed of a crosslinked, grafted polyethylenimine having semipermeable properties disposed on one surface of said microporous substrate, said ultrathin film being formed of polyethylenimine that has been crosslinked with isophthaloyl chloride or terephtaloyl chloride, said crosslinked polyethylenimine also having acrylonitrile or epichlorohydrin grafted thereonto, at what would otherwise be secondary amido sites.
Claim 13
Dependent Claim
13 words
A membrane in accordance with claim 10 wherein said graft reactant is acrylonitrile.
Claim 14
Dependent Claim
13 words
A membrane in accordance with claim 10 wherein said graft reactant is epichlorohydrin.
Claim 15
Dependent Claim
29 words
A composite semipermeable membrane in accordance with claim 10 wherein said polyethylenimine contains at least about 15 percent of its aminoethylene moieties as branches to the main molecular chain.
Claim 16
Dependent Claim
19 words
A membrane in accordance with claim 13 wherein said polyethylenimine has a molecular weight between about 40,000 and 60,000.
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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) | 1979-04-20 | 1979-10-20 | 1980-04-20 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1983-04-20 | 1983-10-20 | 1984-04-20 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1987-04-20 | 1987-10-20 | 1988-04-20 | $7700.00 | Window Closed / Lapsed |