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Title:
PROCESS FOR PRODUCING POROUS FILM AND POROUS FILM
Document Type and Number:
WIPO Patent Application WO/2004/043666
Kind Code:
A1
Abstract:
A process for producing a porous film, comprising casting a polymer solution over a substrate so as to form a film and converting the film to a porous film according to the phase conversion technique, wherein the polymer and the substrate are selected so that the difference (Sa-Sb) between surface tension of polymer constituting the porous film, Sa [mN/m], and surface tension of the substrate, Sb [mN/m], is -10 or greater. In this process, there can be obtained a porous film exhibiting a high open pore ratio at the film surfaces and having uniform micropores from the surfaces through the internal part of the film. The obtained porous film is one having a multiplicity of mutually communicating micropores characterized in that the porous film has a thickness of 5 to 200 μm and with respect to both major surfaces of the porous film, exhibits a surface average pore diameter of 0.01 to 10 μm, a ratio (A/B) of surface average pore diameter (A) to internal part average pore diameter (B) of 0.3 to 3 and a ratio (C/D) of surface average open pore ratio (C) to internal part average open pore ratio (D) of 0.7 to 1.5.

Inventors:
TSUYUMOTO MICHIO (JP)
YAMATO YO (JP)
Application Number:
PCT/JP2003/010426
Publication Date:
May 27, 2004
Filing Date:
August 19, 2003
Export Citation:
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Assignee:
DAICEL CHEM (JP)
TSUYUMOTO MICHIO (JP)
YAMATO YO (JP)
International Classes:
B01D67/00; B01D69/00; B01D69/02; B29C41/12; B29C41/24; B29D7/01; C08J5/22; (IPC1-7): B29C41/12; B29C41/24; B29C41/38; C08J9/28
Domestic Patent References:
WO2001019906A12001-03-22
Foreign References:
JPH09208736A1997-08-12
JP2002037905A2002-02-06
JP2002086476A2002-03-26
JPS6482909A1989-03-28
JP2002260413A2002-09-13
JPH0243911A1990-02-14
JP2003313356A2003-11-06
JP2002120247A2002-04-23
JP2003026849A2003-01-29
JPH09169867A1997-06-30
JPH05148383A1993-06-15
Other References:
See also references of EP 1561561A4
Attorney, Agent or Firm:
Goto, Yukihisa (7-16 Higashitenma 2-chome, Kita-k, Osaka-shi Osaka, JP)
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