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AssigneeNitto Denko Corporation
InventorsMitsuhiro Kanada, Takayuki Yamamoto, Amane Mochizuki, Takahiro Fukuoka
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A porous polyimide having a finely cellular structure and having a low dielectric constant and heat resistance. The porous polyimide can be produced by a process comprising adding a dispersible compound to a polyimide precursor to form a micro-domain structure in which the dispersible compound is dispersed in the polymer so as to have a size smaller than 10 μm and then removing the dispersible compound by extraction with supercritical carbon dioxide to thereby make the precursor porous, wherein the interaction parameter χAB between the polyimide precursor A and the dispersible compound B is larger than 3. This porous polyimide has an average cell diameter smaller than 5 μm and a dielectric constant of 3 or lower.
A process for producing a porous polyimide which comprises preparing a polymer composition having a micro-domain structure made up of a continuous phase comprising a polyimide precursor A and, dispersed therein, a discontinuous phase which comprises a dispersible compound B and has an average diameter smaller than 10 μm, removing the dispersible compound B from the polymer composition, and then converting the polyimide precursor A into a polyimide, an interaction parameter χAB between the polyimide precursor A and the dispersible compound B being larger than 3.
Dependencies are inferred from the claim text.