| 摘要 |
PROBLEM TO BE SOLVED: To obtain a porous film having a sharp pore size distribution, hardly suffering pinholes and other defects and furthermore excellent in surface smoothness. SOLUTION: The porous film has a structure composed of solid particles linked together and the top parts of the solid particles at the surface are formed flat. The solid particles may be composed of an ultrahigh molecular weight polyethylene having a viscosity-average mol.wt. of at least 300,000. The average particle size of the solid particles is, for example, around 10-200μm. The porosity of the porous film is, for example, around 25-80%. The porous film can be manufactured by coating on a support a dispersion comprising solid particles dispersed in a solvent thereby forming a coating film of the solid particles and subsequently fusing contact points of solid particles together and molding flat the top parts of solid particles in the outermost layer.
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