US4240914A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Selective permeable membrane and process for preparing the same
Assignee: Nitto Denko Corp
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Filing: 1978-11-16
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Granted: 1980-12-23
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Expires: 1998-11-16
Abstract
Abstract A selective permeable membrane having self-supporting property which comprises a polyimide polymer consisting essentially of a repeating unit of the formula: ##STR1## wherein R is a divalent organic group, and a process for preparing the same.
Inventors
- 👤 Akio Iwama
- 👤 Yasuo Kihara
- 👤 Masao Abe
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-25 10:57
CPC Classifications
C; C08; C08G; C08G73/00; C08G73/06; C08G73/10; B; B01; B01D; B01D71/00; B01D71/06; B01D71/58; B01D71/62; B01D71/64; Y; Y10; Y10T; Y10T428/00; Y10T428/249921; Y10T428/249953; Y10T428/249981; Y10T428/31504; Y10T428/31721
Claims Analysis
Total Claims: 12
Claim 1
Independent Claim
47 words
A selective permeable membrane having a self-supporting property, which comprises a polyimide polymer consisting essentially of a repeating unit of the formula: ##STR11## wherein R is a divalent organic group wherein the polyimide polymer has an inherent viscosity of about 0.55 to 1.2 measured at 30° C.
Claim 2
Dependent Claim
47 words
A selective permeable membrane having a self-supporting property, which comprises a polyimide polymer consisting essentially of a repeating unit of the formula: ##STR11## wherein R is a divalent organic group wherein the polyimide polymer has an inherent viscosity of about 0.55 to 1.2 measured at 30° C.
Claim 3
Dependent Claim
25 words
The selective permeable membrane of claim 1, wherein the polyimide polymer has an inherent viscosity of about 0.60 to about 1.00 measured at 30° C.
Claim 4
Dependent Claim
17 words
The selective permeable membrane of claim 1, wherein R is an organic group containing an aromatic ring.
Claim 5
Dependent Claim
17 words
The selective permeable membrane of claim 1, wherein R is an organic group containing a hydrophilic group.
Claim 6
Dependent Claim
20 words
The selective permeable membrane of claim 1, wherein R is an organic group containing an aromatic ring and hydrophilic group.
Claim 7
Dependent Claim
36 words
The selective permeable membrane of claim 1, wherein said membrane comprises a skin layer and a porous layer, wherein the pore size of the skin layer does not exceed the pore size of the porous layer.
Claim 8
Dependent Claim
21 words
The selective permeable membrane of claim 1, wherein the number of repeating units in said polymer is about 60 to 300.
Claim 9
Dependent Claim
19 words
The selective permeable membrane of claim 1, wherein said polymer has a molecular weight of about 20,000 to 120,000.
Claim 10
Dependent Claim
26 words
The selective permeable membrane of claim 1, wherein imide linking groups comprise at least about 70% of all of the linking groups of the polyimide polymer.
Claim 11
Dependent Claim
25 words
The selective permeable membrane of claim 9, wherein imide linking groups comprise at least 90% of all of the linking groups of the polyimide polymer.
Claim 12
Dependent Claim
26 words
The selective permeable membrane of claim 10, wherein imide linking groups comprise from 98 to 100% of all of the linking groups of the polyimide polymer.
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) | 1983-12-23 | 1984-06-23 | 1984-12-23 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1987-12-23 | 1988-06-23 | 1988-12-23 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1991-12-23 | 1992-06-23 | 1992-12-23 | $7700.00 | Window Closed / Lapsed |