POLYIMIDE FIBER PAPER USING NON-THERMOPLASTIC POLYMER

As far as the characteristic properties of films are concerned， there are limits to the thermal insulation and gas/liquid permeability properties of polyimide films， and thus there has been anticipation for the development of a flexible sheetlike product that improves these characteristic properties while making the most of the high functionality of polyimides. Additionally， when polyimide films are made thicker， ordinarily this leads to higher cost as well as to an increase in weight， and thus there is demand for the development of a polyimide sheetlike product that is thick and lightweight at low cost. [Means for solving this problem] In order to solve this problem， the present invention provides a manufacturing method for a polyimide fiber paper intermediate structure X， said manufacturing method comprising: a short fiber preparation step in which shaved short fibers of a non-thermoplastic polyimide are prepared; and an intermediate structure X formation step in which the polyimide fiber paper intermediate structure X is formed， said polyimide fiber paper intermediate structure X having the short fibers temporarily fixed therein using a water-soluble thermoplastic polymer and/or a water-insoluble thermoplastic polymer， said thermoplastic polymer(s) having a melting point that is lower than the glass transition temperature of the polyimide.