EP0408378A2
Expired / Lapsed
EP
⏱️ 0.0 years remaining
Hydrophilic semi-permeable PTFE membranes and their manufacture
Assignee: WL Gore and Associates UK Ltd
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Filing: 1990-07-12
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Granted: —
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Expires: 2010-07-12
Abstract
Abstract A hydrophilic, semi-permeable membrane comprises a porous 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 porous PTFE membrane substantially hydrophilic and protein affinitive. The preferred hydrophilic polymer is polyvinyl alcohol, and the complexing agent is preferably a dibasic inorganic acid, such as boric acid, or a salt thereof. Such hydrophilic, semi-permeable membranes are particularly suitable for protecting the target area of a body fluid diagnostic test strip, and as cell culture support members. Methods of forming the membranes are also described.
Inventors
- 👤 Edward George Norman
Bibliographic Details
Application Number
—
Jurisdiction
EP
Data Source
google_patents
Last Synchronized
2026-10-23 19:11
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: 22
Claim 1
Independent Claim
58 words
A hydrophilic, semi-permeable membrane comprising a porous PTFE (polytetrafluoroethylene) membrane having the internal and external surfaces of the membrane structure coated by a hydrophilic polymer which adheres to the membrane structure, characterised in that the hydrophilic polymer is combined with a complexing agent to form a complex which renders the porous PTFE membrane substantially hydrophilic and protein affinitive.
Claim 2
Dependent Claim
58 words
A hydrophilic, semi-permeable membrane comprising a porous PTFE (polytetrafluoroethylene) membrane having the internal and external surfaces of the membrane structure coated by a hydrophilic polymer which adheres to the membrane structure, characterised in that the hydrophilic polymer is combined with a complexing agent to form a complex which renders the porous PTFE membrane substantially hydrophilic and protein affinitive.
Claim 3
Dependent Claim
19 words
A semi-permeable membrane according to claim 1, in which the hydrophilic polymer is an oxygen containing, water soluble polymer.
Claim 4
Dependent Claim
25 words
A semi-permeable membrane according to claim 2, in which the hydrophilic polymer is polyvinyl alcohol, polyvinyl acetate, polyvinyl pyrollidone, or a copolymer or mixture thereof.
Claim 5
Dependent Claim
32 words
A semi-permeable membrane according to claim 3, in which the hydrophilic polymer is a polyvinyl alcohol which is at least 80% hydrolysed and which has a molecular weight of less than 50000.
Claim 6
Dependent Claim
23 words
A semi-permeable membrane according to any one of the preceding claims, in which the complexing agent is an ionic buffer salt or acid.
Claim 7
Dependent Claim
21 words
A semi-permeable membrane according to claim 5, in which the complexing agent is a dibasic inorganic acid or a salt thereof.
Claim 8
Dependent Claim
18 words
A semi-permeable membrane according to claim 6, in which the complexing agent is boric acid or sodium borate.
Claim 9
Dependent Claim
42 words
A semi-permeable membrane according to any one of the preceding claims, in which the porous PTFE membrane is an expanded PTFE membrane having an average pore size of from 0.2 to 15 microns as defined by the bubble point method ASTM F316-70.
Claim 10
Dependent Claim
24 words
A semi-permeable membrane according to any one of the preceding claims, in which the thickness of the membrane is from 0.01 to 0.2 mm.
Claim 11
Dependent Claim
25 words
A semi-permeable membrane according to any one of the preceding claims, in which the porous PTFE membrane is laminated to a non-woven fabric support layer.
Claim 12
Dependent Claim
24 words
A semi-permeable membrane according to claim 10, in which the non-woven fabric support layer is formed of polyester, polypropylene, nylon, or regenerated cellulose fibres.
Claim 13
Dependent Claim
24 words
A semi-permeable membrane according to claim 10 or claim 11, in which the thickness of the support layer is from 0.1 to 0.75 mm.
Claim 14
Independent Claim
106 words
A method of producing a semi-permeable membrane as defined in any one of the preceding claims, comprising subjecting the porous PTFE membrane to a treatment solution containing the hydrophilic polymer, the complexing agent, 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 15
Independent Claim
130 words
A method of producing a semi-permeable membrane as defined in any one of claims 1 to 12, comprising subjecting the porous PTFE membrane to a treatment solution containing the hydrophilic 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 the complexing agent 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 16
Dependent Claim
24 words
A method according to claim 13 or claim 14, in which the solvent in the treatment solution is an aliphatic alcohol or a ketone.
Claim 17
Dependent Claim
17 words
A method according to claim 15, in which the solvent is ethanol, methanol, propanol, butanol, or acetone.
Claim 18
Independent Claim
36 words
A method according to any one of claims 13 to 16, in which the treatment solution also contains water in an amount which is from 20% to 60% by volume of the water and solvent mixture.
Claim 19
Independent Claim
42 words
A method according to any one of claims 13 to 17, in which the hydrophilic polymer is present in the treatment solution in an amount which is from 0.2% to 5% weight by volume of the solvent or solvent and water mixture.
Claim 20
Independent Claim
36 words
A method according to any one of claims 13 to 18, in which the complexing agent is present in the respective solution in an amount which is less than 10% weight by volume of the solution.
Claim 21
Independent Claim
24 words
A method according to any one of claims 13 to 19, in which the treatment solution also contains a surfactant as a dispersion agent.
Claim 22
Independent Claim
23 words
A method according to any one of claims 13 to 20, in which the membrane is impregnated by immersion in the treatment solution.
References Cited (Backward Citations)
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