METHOD FOR PREPARING CARBON FIBER AND PRECURSOR FIBER FOR CARBON FIBER

摘要

The method for preparing a carbon fiber of the present invention includes the steps of: preparing a polyacrylonitrile-based polymer solution; spinning the polyacrylonitrile-based polymer solution to prepare a precursor fiber for a carbon fiber, the precursor fiber having a water content of 20-50 %; converting the precursor fiber for a carbon fiber into a preliminary flame-retarded fiber while stretching the precursor fiber for a carbon fiber at an elongation rate of -10~-0.1% or 0.1 - 5% at 180~220°C in air; converting the preliminary flame-retarded fiber into a flame-retardant fiber while stretching the preliminary flame-retarded fiber at an elongation rate of -5~5% at 200~300 °C in air; and heating the flame-retardant fiber under an inert atmosphere to carbonize the flame-retardant fiber.