Process for the production of composite membranes

• US 4,242,159 A
• Filed: 02/26/1979
• Issued: 12/30/1980
• Est. Priority Date: 02/25/1978
• Status: Expired due to Term

• Current Assignee: Battelle-Institut EV Am Romerhof
• Original Assignee: Battelle-Institut EV
• Inventors: Reiner, Roland, Klimmek, Albrecht, Krieger, Wolfram
• Primary Examiner(s): Lawrence, Evan K.
• Application Number:
  US06/014,952
• Time in Patent Office: 673 Days
• Field of Search: 156/155, 156/230, 156/236, 210/490, 210/500 M, 210/506
• US Class Current: 156/155
• CPC Class Codes: B01D 69/122 Separate manufacturing of ultra-thin membranes

Abstract

A process for the production of a composite membrane consisting of a porous supporting membrane and a thin separating membrane. The separating membrane is produced on the surface of a carrier film (consisting essentially of a soluble polymer). The carrier film coated with the separating membrane is placed with its separating membrane side on a porous supporting membrane such that the separating membrane is between the supporting membrane and the carrier film. The carrier film is then dissolved.

Claims

1. In a process for the production of a composite membrane consisting of a porous supporting membrane and a thin separating membrane, the improvement characterized by the steps of producing a separating membrane on the surface of a carrier film consisting essentially of at least one soluble polymer, placing the carrier film having the separating membrane thereon with its separating membrane side on a porous supporting membrane such that the separating membrane is between the supporting membrane and the carrier film, and then dissolving the carrier film.

2. Process as claimed in claim 1 wherein the carrier film contains at least one soluble polymer selected from the group consisting of polyvinyl alcohol, partially acetylated polyvinyl alcohol, polyacrylic acid, a salt of polyacrylic acid, polymethacrylic acid, a salt of polymethacrylic acid, polyvinylpyrrolidone, polyacrylamide, polyvinyl acetate, a copolymer of the aforegoing, alginic acid, a salt of alginic acid, carboxymethylcellulose, cellulose acetate, cellulose, polycarbonate, and a mixture of one or more of the aforegoing.

3. Process as claimed in claim 2 wherein the carrier film is 5 to 100 μ

m thick.

4. Process as claimed in claim 1 wherein the carrier film consists essentially of a water-soluble polymer.

5. Process as claimed in claim 4 wherein the carrier film is 5 to 100 μ

m thick.

6. Process as claimed in claim 5 wherein the carrier film is 20 to 30 μ

m thick.

7. Process as claimed in claim 4 wherein the carrier film contains up to 50 weight percent, related to the weight of the polymer, of a plasticizer.

8. Process as claimed in claim 7 wherein the carrier film contains 10 to 20 weight percent, related to the weight of the polymer, of a plasticizer.

9. Process as claimed in claim 7 wherein the polymer is polyvinyl alcohol and the plasticizer for the polyvinyl alcohol is polyethylene glycol or sorbite.

10. Process as claimed in claim 1 wherein the carrier film is produced from a polymeric solution to which a nonionic wetting agent has been added.

11. Process as claimed in claim 1 wherein the carrier film contains up to 50 weight percent, related to the weight of the polymer, of a plasticizer.

12. Process as claimed in claim 1 wherein the production step is achieved by coating said separating membrane on said carrier layer.

13. Process as claimed in claim 1 wherein the separating membrane is produced from a polymeric solution to which a nonionic wetting agent has been added.