Ube Industries, Inc.

Ube Corporation

Yuuichi Fujii

Makoto Matsuo

Shyusei Ohya

Kenji Fukunaga

Hiroshi Shimazaki

Shigeru Yao

Yukihiko Asano

Kimio Nakayama

Yoshiaki Watanabe

Keita Bamba

Makoto Babazono

Jun Takagi

Shusei Ohya

Dai Yokoyama

The present invention pertains to a porous polyimide film production method and a porous polyimide film produced using said method, said method including: a step (1) in which a poly(amic acid) solution comprising 40%-97% by mass organic polar solvent and 3%-60% by mass poly(amic acid) having an intrinsic viscosity, comprising tetracarboxylic acid units and diamine units, of 1.0-3.0 is cast in film form and immersed in or caused to come in contact with a coagulating solvent having water as an essential component thereof, and a porous film of poly(amic acid) is produced; and a step (2) in which the porous film of poly(amic acid) obtained in said step is heat treated and imidized. Shrinkage in the film longitudinal direction and transverse direction after heat treatment is suppressed to no more than 8% for each direction and the speed of temperature increase in a temperature range of at least 200&#xb0; C. during the heat treatment is at least 25&#xb0; C./min.

Porous polyimide film production method and porous polyimide film produced using said method

A porous polyimide film having a three-layer structure that comprises two surface layers (a) and (b) and a macrovoid layer sandwiched between the surfaces layers (a) and (b). The macrovoid layer has a partition wall bonding to the surface layers (a) and (b), and multiple macrovoids each surrounded by the partition wall and the surface layers (a) and (b) and having a mean pore size in the film plane direction of from 10 to 500 &#x3bc;m. The partition wall of the macrovoid layer has a thickness of from 0.1 to 50 &#x3bc;m and has multiple pores having a mean pore size of from 0.01 to 50 &#x3bc;m. The surface layers (a) and (b) each have a thickness of from 0.1 to 50 &#x3bc;m, at least one of the surface layers has multiple pores having a mean pore size of from more than 5 &#x3bc;m to 200 &#x3bc;m, and the other surface layer has multiple pores having a mean pore size of from 0.01 to 200 &#x3bc;m. The pores in the partition wall of the macrovoid layer as well as in the surface layers (a) and (b) communicate with each other and further communicate with the macrovoids. The film has a total thickness of from 5 to 500 &#x3bc;m and a porosity of from 60 to 95%.

Porous polyimide membrane and process for production thereof

A metal-supported porous carbon film wherein metal fine particles with a mean particle diameter of 0.7-20 nm are dispersed and supported on pore surface walls, fuel cell electrodes employing the metal-supported porous carbon film, a membrane-electrode assembly comprising the fuel cell electrodes bonded on both sides of a polymer electrolyte film, and a fuel cell comprising the fuel cell electrode as a constituent element. The support structure is such that metal fine particles having a controlled particle size are uniformly supported to allow effective utilization of the metal-based catalyst, and the fabrication steps are simple.

Metal-supported porous carbon film, fuel cell electrode and fuel cell employing the electrode

A polyimide porous film obtained by drying and imidizing a polyimide precursor porous film which is substantially homogeneous on both sides, the polyimide porous film having pores on both sides wherein the pores all satisfy the conditions: 1) the difference in the mean pore size of both sides is less than 200% based on the smaller average value of the mean pore size, 2) the coefficient of variation for the pore size on each side is smaller than 70%, 3) the coefficient of variation for the pore centroid distance on each side is smaller than 50%, and 4) the mean pore size on each side is 0.05-5 &mgr;m.

Polyimide porous film

Growing community of inventors

Ichihara, Japan

Yuuichi Fujii