POLYIMIDE NONWOVEN FABRIC AND PROCESS FOR PRODUCTION THEREOF

摘要

The invention provides a nonwoven fabric which exhibits excellent heat resistance, mechanical strength and dimensional stability under heat even in applications accompanied with the exposure to high temperature and has an extremely large surface area and high filter performance. The fabric is made of polyimide fibers which are prepared from a raw material comprising as the essential components an aromatic tetracarboxylic acid and antissu non tissé de péo aromatic diamine having a benzoxazole structure through polycondensation and have fiber diameters of 0.001 to 1µm. This fabric can be produced by a process which comprises the step of forming a polyimide precursor nonwoven fabric by charge-spinning a polyamic acid prepared from a raw material comprising as the essential components an aromatic tetracarboxylic acid and an aromatic diamine having a benzoxazole structure through polycondensation and the step of subjecting the polyimide precursor fibers constituting the obtained precursor nonwoven fabric to imidation.