Patent US4964991A successfully refreshed from Google Patents.
US4964991A
Expired / Lapsed
US
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Flat permeable membrane and for manufacture thereof
Assignee: Terumo Corp
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Filing: 1987-08-12
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Granted: 1990-10-23
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Expires: 2007-08-12
Abstract
Abstract A flat permeable membrane of polyolefin 10 to 500 mu m in thickness, which membrane has compact layers of intimately bound fine particles of polyolefin formed one each in the opposite surface regions of the membrane and a layer of an aggregate of fine discrete particles of an average diameter of 0.01 to 5 mu m formed between the compact layers and, consequently, has fine through pores labyrinthically extended in the direction of thickness of the membrane to establish communication between the opposite surfaces of the membrane and a method for the manufacture of the permeable membrane.
Inventors
- 👤 Yukio Seita
- 👤 Makoto Emi
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-08 13:06
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; B01D71/261; B01D71/262; B01D2323/00; B01D2323/15; B01D2323/21; B01D2325/00; B01D2325/02; B01D2325/022; B01D2325/023; C08J2201/00; C08J2201/04; C08J2201/054; C08J2201/0542; C08J2201/0543; C08J2201/0545; C08J2201/0546; C08J2323/00; C08J2323/02
Claims Analysis
Total Claims: 19
Claim 1
Independent Claim
103 words
A method for manufacturing a flat permeable membrane, which method comprises: mixing a molten polyolefin, a crystal seed forming agent, and an organic filler uniformly dispersible in said molten polyolefin and easily soluble in an extractant to be used, discharging the resultant mixture in a molten state through a die to obtain a molten membrane, cooling and solidifying the discharged molten membrane by contacting said molten membrane with a cooling fluid, and removing said organic filler by contacting the cooled and solidified membrane with an extactant capable of dissolving the organic filler but incapable of dissolving said polyolefin and said crystal forming agent.
Claim 2
Independent Claim
103 words
A method for manufacturing a flat permeable membrane, which method comprises: mixing a molten polyolefin, a crystal seed forming agent, and an organic filler uniformly dispersible in said molten polyolefin and easily soluble in an extractant to be used, discharging the resultant mixture in a molten state through a die to obtain a molten membrane, cooling and solidifying the discharged molten membrane by contacting said molten membrane with a cooling fluid, and removing said organic filler by contacting the cooled and solidified membrane with an extactant capable of dissolving the organic filler but incapable of dissolving said polyolefin and said crystal forming agent.
Claim 3
Dependent Claim
26 words
A method according to claim 1, wherein said organic filler is a hydrocarbon having a boiling point not less than the melting point of said polyolefin.
Claim 4
Dependent Claim
12 words
A method according to claim 2, wherein said hydrocarbon is liquid paraffin.
Claim 5
Dependent Claim
68 words
A method according to claim 2, wherein said method said hydrocarbon is an α-olefin oligomer selected from the group consisting of ethylene oligomers, propylene oligomers, and ethylene-propylene oligomers; and 35 to 40 parts by weight of a said crystal seed forming agent are used and said crystal seed forming agent is selected from the group consisting of dibenzylidene sorbitol, 1,3,2,4-bis(p-methylbenzylidene)-sorbitol, 1,3,2,4-(p-ethylbenzylidene)-sorbitol, bis (4-t-butylphenyl)-sodium phosphate, adipic acid and kaolin.
Claim 6
Dependent Claim
34 words
A method according to claim 1, wherein the amount of said organic filter used is in the range of 35 to 300 parts by weight based on 100 parts by weight of said polyolefin.
Claim 7
Dependent Claim
25 words
A method according to claim 1, wherein said polyolefin is at least one member selected from the group consisting of polyethylene, polypropylene, and ethylene-propylene copolymer.
Claim 8
Dependent Claim
43 words
A method according to claim 1, wherein said crystal seed forming agent is an organic heat-resisting substance having a melting point of not less than 150° C. and a gel point not less than the temperature at which said polyolefin begins to carystallize.
Claim 9
Dependent Claim
38 words
A method according to claim 1, wherein the amount of said crystal seed forming agent to be used is in the range of 0.1 to 5 parts by weight based on 100 parts by weight of said polyolefin.
Claim 10
Dependent Claim
24 words
A method according to claim 1, wherein said extractant is at least one member selected from the group consisting of alcohols and halogenated hydrocarbons.
Claim 11
Dependent Claim
13 words
A method according to claim 1, wherein said cooling fluid is a liquid.
Claim 12
Dependent Claim
17 words
A method according to claim 1, wherein said cooling liquid is incapable of dissolving said organic filler.
Claim 13
Dependent Claim
14 words
A method according to claim 1, wherein said cooling fluid is an inert gas.
Claim 14
Dependent Claim
12 words
A method according to claim 12, wherein said inert gas is air.
Claim 15
Dependent Claim
19 words
A method according to claim 1, wherein the temperature for cooling and solidifying is not more than 120° C.
Claim 16
Dependent Claim
12 words
A method according to claim 1, wherein said cooling liquid is water.
Claim 17
Dependent Claim
15 words
A method according to claim 1, wherein said polyolefin has more than 97% of tacticity.
Claim 18
Dependent Claim
16 words
A method according to claim 1, wherein said crystal forming agent is 1,3,2,4-dibenzylidene-sorbitol or 1,3,2,4-bis (p-methylbenzylidene)-sorbitol.
Claim 19
Dependent Claim
21 words
A flat permeable membrane produced in accordance with the process of claim 1 for removing pathogenic macromolecules from blood plasma compositions.
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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) | 1993-10-22 | 1994-04-23 | 1994-10-23 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1997-10-22 | 1998-04-23 | 1998-10-23 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2001-10-22 | 2002-04-23 | 2002-10-23 | $7700.00 | Window Closed / Lapsed |