Flat or capillary membrane based on a homogeneous mixture of polyvinylidene fluoride and a second polymer which can be rendered hydrophilic by chemical reaction

• US 5,066,401 A
• Filed: 07/13/1990
• Issued: 11/19/1991
• Est. Priority Date: 07/13/1989
• Status: Expired due to Fees

• Current Assignee: Akzo Nobel N.V. (Nouryon BV)
• Original Assignee: Akzo Nobel N.V. (Nouryon BV)
• Inventors: Muller, Heinz-Joachim, Spindler, Ernst, Eberhard, Gunter, Volker, Helmut, Krauss, Lothar, Sluma, Heinz-Dieter
• Primary Examiner(s): Sever, Frank
• Application Number:
  US07/552,051
• Time in Patent Office: 494 Days
• Field of Search: 264/41, 264/45.1, 55/16, 55/158, 210/500.42, 210/500.35, 521/53, 521/918, 521/145
• US Class Current: 210/500.35
• CPC Class Codes: B01D 2323/02 Hydrophilization
• CPC Class Codes: B01D 2323/08 Specific temperatures applied
• CPC Class Codes: B01D 2323/081 Heating
• CPC Class Codes: B01D 2323/082 Cooling
• CPC Class Codes: B01D 2323/12 Specific ratios of components used
• CPC Class Codes: B01D 2323/36 Introduction of specific chemical groups
• CPC Class Codes: B01D 2325/36 Hydrophilic membranes
• CPC Class Codes: B01D 67/0009 by phase separation, sol-gel transition, evaporation or solvent quenching
• CPC Class Codes: B01D 67/00091 by evaporation
• CPC Class Codes: B01D 67/003 by selective elimination of components, e.g. by leaching
• CPC Class Codes: B01D 67/0093 Chemical modification
• CPC Class Codes: B01D 69/141 Heterogeneous membranes, e.g. containing dispersed material; Mixed matrix membranes
• CPC Class Codes: B01D 71/34 Polyvinylidene fluoride
• CPC Class Codes: C12N 11/082 obtained by reactions only involving carbon-to-carbon unsaturated bonds
• CPC Class Codes: C12N 11/087 Acrylic polymers

Abstract

Membranes are based on a homogeneous mixture of polyvinylidene fluoride and a second polymer which can be rendered hydrophilic by chemical reaction. The membranes contain 70 to 98 percent by weight of polyvinylidene fluoride and 2 to 30 percent by weight of a polymer formed essentially from polymethyl and/or polyethyl acrylate, and have a maximum pore size in the range from 0.005 to 10 μm. They can be rendered hydrophilic by means of at least partial hydrolysis, at least partial transesterification with an alcohol which is at least trihydric and contains 3 to 12 carbon atoms, and/or at least partial aminolysis with an amino compound having 2 to 8 carbon atoms. The flat or capillary membranes which have been rendered hydrophilic can contain on their total surface 0.001 to 10 milliequivalents/g of membrane, preferably 0.01 to 5 m equivalents/g of membrane, of --COOH, --OH or --NH₂ groups or corresponding mixtures of these hydrophilic functional groups. Such membranes can be used, in particular, for immobilizing biochemically active compounds.

Claims

1. A membrane comprising a homogeneous mixture of 70 to 98 percent by weight of polyvinylidene fluoride and 2 to 30 percent by weight of a polymer which can be rendered hydrophilic by chemical reaction formed essentially from polymethyl and/or polyethyl acrylate, said membrane having a maximum pore size in the range from 0.005 to 10 μ

m.

2. A membrane as claimed in claim wherein said maximum pore size is in the range from 0.01 to 2 μ

m.

3. A membrane as claimed in claim 2, wherein said maximum pore size is in the range of 0.05 to 0.8 μ

m.

4. A membrane as claimed in the polyvinylidene fluoride has an average weight (weight-average) of 30,000 to 500,000, and said polymer has an average molecular weight of 5,000 to 1,000,000.

5. A membrane as claimed in claim 4, wherein the polyvinylidene fluoride has an average molecular weight of 50,000 to 500,000 and said polymer has an average molecular weight of 50,000 to 200,000.

6. A membrane as claimed in claim i, which comprises a homogeneous mixture of 80 to 95% by weight of polyvinylidene fluoride and 5 to 20% by weight of said polymer.

7. A membrane as claimed in claim which contains 0.001 to 10 milliequivalents/g of membrane of at least one of the hydrophilic functional groups selected from the group consisting of --OH, --NH₂ and --COOH groups on a total surface of said membrane.

8. A membrane as claimed in claim 7, which contains 0.01 to 5 milliequivalents/g of membrane of said at least one of said hydrophilic functional groups on said total surface.

9. A membrane as claimed in claim 7, further comprising an immobilized biochemically active compound.

10. A membrane as claimed in claim 7, wherein said membrane is a flat or capillary membrane.