Production process for improving breaking strength and heat resistance of meta-aramid fiber

The invention relates to a production process for improving breaking strength and heat resistance of meta-aramid fiber, which comprises the following steps: dissolving polyisophthaloyl metaphenylene diamine resin in sulfuric acid and an organic cosolvent for degassing, spinning the obtained meta-aramid spinning solution, drying, dipping in a coagulating bath consisting of a mixed solution of H2SO4 and CaCl2, and carrying out vacuum drying to obtain the meta-aramid fiber with high breaking strength and high heat resistance. Collecting to obtain as-spun meta-position aramid fiber; the preparation method comprises the following steps: pre-stretching the as-spun meta-position aramid fiber at 150-200 DEG C at the rate of 10-100 mm/min, keeping the stretching state, cooling to room temperature, carrying out heat treatment at 150-200 DEG C for 0.5-6 hours, cooling to room temperature, carrying out main stretching at 200-300 DEG C at the rate of 10-100 mm/min, keeping the stretching state, cooling to room temperature