Patent ID: 7803460

Claim:
A filament bundle type nano-sized fiber produced through a process comprising electrospinning a spinning solution or a spinning melt in drops using a spinneret to which a critical voltage is applied, and continuously collecting the spun drops on a multi-collector, the spinning solution having been produced by dissolving a copolymer consisting of two or more kinds of polymers in a solvent, the spinning melt being produced by melting the polymers, and the multi-collector is selected from the group consisting of a plate type collector, a roll type collector, and a combination thereof wherein each of the polymers is a polyamide-polyimide copolymer including a compound expressed by Formula 1, in which m is 1-99 mol %, and the other compound expressed by Formula 2, in which n is 1-99 mol %: and a filament type nanofiber is a nano-sized long fiber having a diameter of 1-1,000 nm.