Dyeing method for pretreating polyimide fiber by adopting chemical reagent

The invention relates to a dyeing method for pretreating polyimide fibers by adopting a chemical reagent, which comprises the following steps: (1) soaking the polyimide fibers in a first soaping solution, fishing out and drying; (2) soaking the polyimide fibers dried in the step (1) in an alkali pretreatment solution for alkali pretreatment to obtain alkali treated fibers, cleaning the alkali treated fibers until the alkali treated fibers are neutral, and drying the alkali treated fibers; (3) soaking the polyimide fiber in the dye liquor, dyeing, cooling to room temperature, and washing until the pH is neutral, so as to obtain the dyed polyimide fiber; and (4) soaking the dyed polyimide fiber obtained in the step (3) in a second soaping solution for post-treatment, and then taking out and drying to obtain a target product. Compared with the prior art, the method has the advantages that the operation is simple, special equipment is not needed, the cost is low, the dosage of the dye and the carrier can be reduc