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US5041225A
Expired / Lapsed
US
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Hydrophilic semi-permeable PTFE membranes and their manufacture
Assignee: Individual
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Filing: 1990-07-10
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Granted: 1991-08-20
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Expires: 2010-07-10
Abstract
Abstract A hydrophilic, semipermeable membrane comprises a microporous PTFE membrane having the internal and external surfaces of the membrane structure coated by a complex formed by the combination of a hydrophilic polymer which adheres to the membrane structure and a complexing agent, the complex rendering the microporous PTFE membrane substantially hydrophilic and protein affinitive. The preferred hydrophilic polymariz/polyvinyl alcohol, and the complexing agent is preferably a dibasic inorganic acid, such as boric acid, or a salt thereof. Such hydrophilic, semipermeable membranes are particularly suitable for protecting the target area of a body fluid diagnostic test strip, and a cell culture support members. Methods of forming the membranes are also described.
Inventors
- 👤 Eddie Norman
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-05 07:27
CPC Classifications
B; B01; B01D; B01D67/00; B01D67/0081; B01D67/0088; B01D71/00; B01D71/06; B01D71/30; B01D71/32; B01D71/36; C; C08; C08J; C08J9/00; C08J9/36; C08J9/40; C08J9/42; G; G01; G01N; G01N33/00; G01N33/48; G01N33/50; G01N33/52; C08J2327/00; C08J2327/02; C08J2327/12; C08J2327/18; C08J2421/00; C08J2439/00
Claims Analysis
Total Claims: 14
Claim 1
Independent Claim
65 words
A hydrophilic, semi-permeable membrane comprising a porous polytetrafluoroethylene membrane having the internal and external surfaces of the membrane structure coated by a complex formed by the combination of a hydrophilic oxygen containing, water soluble polymer which adheres to the membrane structure and a complexing agent that is an ionic buffer salt or acid, the complex rendering the porous PTFE membrane substantially hydrophilic and protein affinitive.
Claim 2
Dependent Claim
65 words
A hydrophilic, semi-permeable membrane comprising a porous polytetrafluoroethylene membrane having the internal and external surfaces of the membrane structure coated by a complex formed by the combination of a hydrophilic oxygen containing, water soluble polymer which adheres to the membrane structure and a complexing agent that is an ionic buffer salt or acid, the complex rendering the porous PTFE membrane substantially hydrophilic and protein affinitive.
Claim 3
Dependent Claim
25 words
A semi-permeable membrane according to claim 1, in which the hydrophilic polymer is polyvinyl alcohol, polyvinyl acetate, polyvinyl pyrollidone, or a copolymer or mixture thereof.
Claim 4
Dependent Claim
32 words
A semi-permeable membrane according to claim 2, in which the hydrophilic polymer is a polyvinyl alcohol which is at least 80% hydrolysed and which has a molecular weight of less than 5000.
Claim 5
Dependent Claim
21 words
A semi-permeable membrane according to claim 1, in which the complexing agent is a dibasic inorganic acid or a salt thereof.
Claim 6
Dependent Claim
18 words
A semi-permeable membrane according to claim 4, in which the complexing agent is boric acid or sodium borate.
Claim 7
Dependent Claim
21 words
A semi-permeable membrane according to claim 1 in which the porous PTFE membrane is laminated to a non-woven fabric support layer.
Claim 8
Dependent Claim
24 words
A semi-permeable membrane according to claim 6 in which the non-woven fabric support layer is formed of polyester, polypropylene, nylon, or regenerated cellulose fibres.
Claim 9
Independent Claim
109 words
A method of producing a semi-permeable membrane comprising subjecting a porous PTFE membrane to a treatment solution containing a hydrophilic oxygen containing, water soluble polymer, a complexing agent that is an ionic buffer salt or acid, and a solvent in which the hydrophilic polymer and the complexing agent are soluble and which is capable of wetting the PTFE membrane, so that the pore structure of the membrane is substantially completely impregnated by said solution, and drying the membrane to evaporate the solvent and thereby leave a complex formed by a combination of the hydrophilic polymer and the complexing agent coated on the internal and external surfaces of the membrane.
Claim 10
Independent Claim
109 words
A method of producing a semi-permeable membrane comprising subjecting a porous PTFE membrane to a treatment solution containing a hydrophilic oxygen containing, water soluble polymer, a complexing agent that is an ionic buffer salt or acid, and a solvent in which the hydrophilic polymer and the complexing agent are soluble and which is capable of wetting the PTFE membrane, so that the pore structure of the membrane is substantially completely impregnated by said solution, and drying the membrane to evaporate the solvent and thereby leave a complex formed by a combination of the hydrophilic polymer and the complexing agent coated on the internal and external surfaces of the membrane.
Claim 11
Independent Claim
131 words
A method of producing a semi-permeable membrane comprising subjecting porous PTFE membrane to a treatment solution containing a hydrophilic oxygen containing, water soluble polymer and a solvent for the hydrophilic polymer which is capable of wetting the PTFE membrane so that the pore structure of the membrane is substantially completely impregnated by said solution drying the membrane to evaporate the solvent and thereby leave a coating of the hydrophilic polymer adhered to the internal and external surfaces of the membrane, then subjecting the treated membrane to a solution of a complexing agent that is an ionic buffer salt or acid so that the pore structure of the membrane is substantially completely impregnated thereby and the complexing agent combines with the hydrophilic polymer coating to form a complex, and drying the membrane.
Claim 12
Independent Claim
131 words
A method of producing a semi-permeable membrane comprising subjecting porous PTFE membrane to a treatment solution containing a hydrophilic oxygen containing, water soluble polymer and a solvent for the hydrophilic polymer which is capable of wetting the PTFE membrane so that the pore structure of the membrane is substantially completely impregnated by said solution drying the membrane to evaporate the solvent and thereby leave a coating of the hydrophilic polymer adhered to the internal and external surfaces of the membrane, then subjecting the treated membrane to a solution of a complexing agent that is an ionic buffer salt or acid so that the pore structure of the membrane is substantially completely impregnated thereby and the complexing agent combines with the hydrophilic polymer coating to form a complex, and drying the membrane.
Claim 13
Dependent Claim
24 words
A method according to claim 8 or claim 9 in which the solvent in the treatment solution is an aliphatic alcohol or a ketone.
Claim 14
Dependent Claim
17 words
A method according to claim 10 in which the solvent is ethanol, methanol, propanol, butanol, or acetone.
References Cited (Backward Citations)
US4318714A
Cited
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| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
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| 3.5 Years (Year 4) | 1994-08-19 | 1995-02-18 | 1995-08-20 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1998-08-19 | 1999-02-18 | 1999-08-20 | $3760.00 | Window Closed / Lapsed |
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