Preparation method of full-biodegradable elastic fiber

The invention relates to the technical field of fibers, in particular to a preparation method of full-biodegradable elastic fibers. The preparation method comprises the following steps: step 1, preparing raw materials of the elastic fiber, mixing and alcoholizing a polyhydroxy initiator and a metal organic catalyst, then adding into lactone, L-lactide and a chlorine-containing organic solution, mixing, and carrying out ring-opening polymerization reaction to obtain a segmented copolymer of the lactone and the lactide; 2, spinning the segmented copolymer of the lactone and the lactide, wherein the spinning process sequentially comprises melt spinning, side blowing cooling, oiling, winding, stretching and heat setting to complete spinning. Seen from the molecular structure, the fiber is a block polymer, a soft segment is formed by a lactone homopolymer long chain, a hard segment is formed by a lactide homopolymer, the hard segment and the soft segment are alternately arranged to form a repeated structure unit,