Preparation method for polylactic acid fiber filter rod with good temperature resistance

A preparation method for a polylactic acid fiber filter rod with better temperature resistance, comprising the following steps:

• S1:
• acquiring various polylactic acid raw materials, and acquiring a content of a levo-isomer in each polylactic acid raw material;
• selecting at least two kinds of up-to-standard polylactic acid raw materials having the content of the levo-isomer being within a predetermined range;
• S2:
• selecting an up-to-standard polylactic acid raw material having the highest content of the levo-isomer in step S1 to serve as a first component raw material, and induce crystallization by means of drafting stress when spinning is carried out on the first component raw material, so as to obtain a core component;
• selecting an up-to-standard polylactic acid raw material having the lowest content of the levo-isomer in step S1 to serve as a second component raw material, and adding glyceryl triacetate to the second component raw material to obtain a sheath component;
• S3:
• matching the core component with the sheath component according to a preset proportion, such that an outer side of the core component is coated with the sheath component, so as to form sheath-core polylactic acid fiber tows;
• and
• S4:
• carrying out composite forming on a plurality of sheath-core polylactic acid fiber tows to obtain a polylactic acid filter rod.