Porous fluorine resin membrane and process for preparing the same

• US 4,702,836 A
• Filed: 07/11/1986
• Issued: 10/27/1987
• Est. Priority Date: 12/27/1984
• Status: Expired due to Term

• Current Assignee: Asahi Kasei Kogyo Kabushiki Kaisha
• Original Assignee: Asahi Kasei Kogyo Kabushiki Kaisha
• Inventors: Miura, Morikazu, Mutoh, Yoshihiko
• Primary Examiner(s): Foelak, Morton
• Application Number:
  US06/884,519
• Time in Patent Office: 473 Days
• Field of Search: 210/500.23, 210/500.36, 521/61, 521/64, 521/134, 521/145
• US Class Current: 210/500.23
• CPC Class Codes: B01D 67/0027 by stretching
• CPC Class Codes: B01D 67/003 by selective elimination of components, e.g. by leaching
• CPC Class Codes: B01D 71/32 containing fluorine atoms
• CPC Class Codes: C08J 2201/0442 the inorganic phase being a metal, its oxide or hydroxide
• CPC Class Codes: C08J 2323/08 Copolymers of ethene C08J2323/16 takes precedence
• CPC Class Codes: C08J 2327/12 containing fluorine atoms
• CPC Class Codes: C08J 9/26 by elimination of a solid phase from a macromolecular composition or article, e.g. leaching out

Abstract

The invention relates to a porous membrane made of a particular fluorine resin, having excellent chemical resistance, excellent thermal resistance, excellent filtration performance and excellent mechanical properties, and having uniform porous structure comprising minute pores, and also relates to a process for preparing the same. In particular, the invention relates to a porous membrane suited for a microfilter having excellent thermal resistance and excellent filtration performance, especially a porous membrane suited for a microfilter for use in purification of chemicals such as strong acid and strong alkali by utilizing the excellent chemical resistance, and also a process for preparing the same.

Claims

1. A porous fluorine resin membrane comprising a fluorine resin selected from the group consisting of an ethylene-tetrafluoroethylene copolymer, an ethylene-chlorotrifluoroethylene copolymer and polychlorotrifluoroethylene, having a mean pore size of from 0.01 to 5μ

and a porosity of 40 to 90%, and having a three dimensional network structure such that the symbol N designating the number of fibers constituted a network is N≧

2p/D per 1 mm in the thicknesswise direction of the membrane, wherein p represents a porosity (%) and D represents mean pore side (μ

).

2. The porous fluorine resin membrane according to claim 1, wherein the number N of fibers constituted the network is such that N≧

5p/D per 1 mm in the thicknesswise direction of the membrane.

3. The porous fluorine resin membrane according to claim 1, wherein said porous membrane comprises a hollow fiber.