Patent US4743375A successfully refreshed from Google Patents.
US4743375A
Expired / Lapsed
US
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Flat permeable membrane
Assignee: Terumo Corp
•
Filing: 1985-11-08
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Granted: 1988-05-10
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Expires: 2005-11-08
Abstract
Abstract A flat permeable polyolefin membrane 10 to 500 μm in thickness, which has in one surface thereof a compact layer formed of intimately bound fine polyolefin particles and possessed of fine pores and in the interior and the other surface thereof a layer formed of an aggregate of fine discrete polyolefin particles of an average diameter in the range of 0.01 to 5 μm so adjoined as to form fine labyrinthically continuing through pores and which, therefore, establishes communication between the opposite surfaces of said membrane.
Inventors
- 👤 Yukio Seita
- 👤 Makoto Emi
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-27 09:01
CPC Classifications
C; C08; C08J; C08J9/00; C08J9/28; B; B01; B01D; B01D67/00; B01D67/0002; B01D67/0023; B01D67/003; B01D69/00; B01D69/02; B01D69/06; B01D71/00; B01D71/06; B01D71/26; B01D71/262; B01D2323/00; B01D2323/08; B01D2323/081; B01D2323/082; B01D2323/12; C08J2201/00; C08J2201/02; C08J2201/03; C08J2201/04; C08J2201/054; C08J2201/0542; C08J2201/0543; C08J2201/0545; C08J2201/0546; C08J2323/00; C08J2323/02; Y; Y10; Y10T; Y10T428/00; Y10T428/31504; Y10T428/31855; Y10T428/31909; Y10T428/31913; Y10T428/31938
Claims Analysis
Total Claims: 16
Claim 1
Independent Claim
124 words
A flat permeable polyolefin membrane comprising a polyolefin containing a crystal seed forming agent, said membrane having a thickness of 10 to 500 μm and having in one surface thereof as a filtering surface a compact layer formed of intimately bound fine polyolefin particles and possessed of fine pores and in the interior and the other surface thereof a layer formed of an aggregate of fine discrete polyolefin particles of an average diameter in the range of 0.01 to 5 μm so adjoined as to form fine labyrinthically continuing through pores and which, therefore, established communication between the opposite surfaces of said membrane, said membrane having a shrinkage of not more than 6.0% after a heat treatment performed at 121° C. for 120 minutes.
Claim 2
Dependent Claim
124 words
A flat permeable polyolefin membrane comprising a polyolefin containing a crystal seed forming agent, said membrane having a thickness of 10 to 500 μm and having in one surface thereof as a filtering surface a compact layer formed of intimately bound fine polyolefin particles and possessed of fine pores and in the interior and the other surface thereof a layer formed of an aggregate of fine discrete polyolefin particles of an average diameter in the range of 0.01 to 5 μm so adjoined as to form fine labyrinthically continuing through pores and which, therefore, established communication between the opposite surfaces of said membrane, said membrane having a shrinkage of not more than 6.0% after a heat treatment performed at 121° C. for 120 minutes.
Claim 3
Dependent Claim
26 words
A flat permeable polyolefin membrane according to claim 1, wherein the compact layer accounts for not more than 30% of the total thickness of the membrane.
Claim 4
Dependent Claim
23 words
A flat permeable polyolefin membrane according to claim 1, wherein the polyolefin membrane has a porosity in the range of 10 to 85%.
Claim 5
Dependent Claim
20 words
A flat permeable polyolefin membrane according to claim 3, wherein the porosity is in the range of 10 to 60%.
Claim 6
Dependent Claim
29 words
A flat permeable polyolefin membrane according to claim 1, wherein the fine pores of the compact layer have an average diameter in the range of 0.01 to 5 μm.
Claim 7
Dependent Claim
36 words
A flat permeable polyolefin membrane according to claim 1 wherein the fine particles of the layer formed of the aggregate of fine discrete particles have an average diameter in the range of 0.02 to 1.0 μm.
Claim 8
Dependent Claim
28 words
A flat permeable polyolefin membrane according to claim 1 wherein the polyolefin is at least one member selected from the group consisting of polyethylene, polypropylene, and ethylene-propylene copolymer.
Claim 9
Dependent Claim
20 words
A flat permeable polyolefin membrane according to claim 1 wherein the surface constituting the compact layer is flat and smooth.
Claim 10
Dependent Claim
20 words
A flat permeable polyolefin membrane according to claim 1 wherein the porosity is in the range of 10 to 60%.
Claim 11
Dependent Claim
24 words
A flat permeable polyolefin membrane according to claim 9 wherein the thickness of the membrane is in the range of 20 to 300 μm.
Claim 12
Dependent Claim
20 words
A flat permeable polyolefin membrane according to claim 1 which is suitable for use in the separation of blood components.
Claim 13
Dependent Claim
26 words
A flat permeable polyolefin membrane according to claim 11, wherein the average diameter of the fine pores is in the range of 0.02 to 2.0 μm.
Claim 14
Dependent Claim
20 words
A flat permeable polyolefin membrane according to claim 10, wherein the porosity is in the range of 30 to 80%.
Claim 15
Dependent Claim
17 words
A flat permeable polyolefin membrane according to claim 1, wherein the shrinkage is not more than 3.0%.
Claim 16
Dependent Claim
36 words
A flat permeable polyolefin membrane according to claim 1, wherein the crystal seed forming agent is incorporated in an amount of 0.1 to 5 parts by weight based on 100 parts by weight of said polyolefin.
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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) | 1991-05-10 | 1991-11-09 | 1992-05-10 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1995-05-10 | 1995-11-09 | 1996-05-10 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1999-05-10 | 1999-11-09 | 2000-05-10 | $7700.00 | Window Closed / Lapsed |