Process for producing a filter component, electrospinning process for producing a nanofibrous nonwoven, and process for increasing the cohesion of a nanofibrous nonwoven

摘要

Producing filter component comprising a substrate and a nano nonwoven fabric of an aromatic polyimide, comprises: (a) preparing the nano nonwoven fabric from a solution with an electrospinning process; and (b) applying and fixing the nanofibers on the substrate prepared in the step (a). Independent claims are also included for: (1) the electrospinning process for producing the nano nonwoven fabric comprising (i) producing the solution of polyimide in a polar, aprotic solvent with a content of 5-25 mass-%, (ii) adding optionally a surfactant of 15 mass/thousand and 0.01 mass/thousand, and (iii) subjecting the solution to an electric field with the field strength of 1000-4000 V/cm; (2) the nanofibers obtained by the above method; (3) increasing the cohesion of the nano-nonwoven fabric by thermal processing at 280-350[deg] C for 1-30 minutes; (4) the nano nonwoven fabric with increased cohesion obtained by the method; (5) the substrate made of polyimide materials, aramid, glass fiber, polytetrafluoroethylene and/or polyphenylene sulfide; and (6) the filter component molded into a filter bag; and (7) the electrospinnable solution of a polymer in the aprotic polar solvent, comprising (c) polyimide (10-20 mass-%), and (d) optionally surfactant (0.75-12 mass/thousand).