| 摘要 |
PROBLEM TO BE SOLVED: To provide a porous film having homogeneous micro-pores and excellent film strength. SOLUTION: The porous film is characterized as follows. The porous film is composed of a material consisting essentially of a polyetherimide-based resin and the plurality of micro-pores having communicating properties are present. The average pore diameter of the micro-pores is 0.01-10μm. The average pore diameterϕA of the micro-pores on one surface side of the porous film and the average pore diameterϕB of the micro-pores on the other surface side satisfy the relationship of 0.1≤ϕA/ϕB≤10. Furthermore, the porosity is 30-80%. The tensile modulus of elasticity of the porous film is preferably≥50 to≤1,000 MPa. COPYRIGHT: (C)2007,JPO&INPIT
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