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

Abstract

Provided is a preparation method for a polylactic acid fiber filter rod with better temperature resistance, which relates to the technical field of cigarette preparation. The method includes the following steps: separately selecting an up-to-standard polylactic acid raw material having the highest content and having the lowest content of the levo-isomer to prepare a core component and a sheath component; forming sheath-core polylactic acid fiber tows; and carrying out forming on a plurality of sheath-core polylactic acid fiber tows to prepare a polylactic acid filter rod. By means of controlling the proportions and preparation of polylactic acid raw materials, so as to improve the uniformity of an inner-layer structure thereof, and the filter performance of the polylactic acid tows is improved.

What is claimed is: 
     
         1 . A preparation method for a polylactic acid fiber filter rod with better temperature resistance, comprising the following steps:
 S 1 : 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;   S 2 : selecting an up-to-standard polylactic acid raw material having the highest content of the levo-isomer in step S 1  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 S 1  to serve as a second component raw material, and adding glyceryl triacetate to the second component raw material to obtain a sheath component;   S 3 : 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   S 4 : carrying out composite forming on a plurality of sheath-core polylactic acid fiber tows to obtain a polylactic acid filter rod.   
     
     
         2 . The preparation method for the polylactic acid fiber filter rod with better temperature resistance according to  claim 1 , wherein
 in a case that kinds of the up-to-standard polylactic acid raw materials are no less than three, and   before carrying out step S 3 , each of other up-to-standard polylactic acid raw materials, except for the up-to-standard polylactic acid raw materials in step S 2 , is separately processed, to obtain a transitional component; and   during carrying out step S 3 , the transitional component is placed between the core component and the sheath component to form the sheath-core polylactic acid fiber tows of a multi-layer structure.   
     
     
         3 . The preparation method for the polylactic acid fiber filter rod with better temperature resistance according to  claim 2 , wherein
 in a case that the kinds of other up-to-standard polylactic acid raw materials, except for the up-to-standard polylactic acid raw materials in step S 1 , are no less than two,   the processing of other up-to-standard polylactic acid raw materials to obtain the transitional components specifically involves separately processing each of other up-to-standard polylactic acid raw materials to obtain a plurality of transitional components; and   when the transitional components are placed between the core component and the sheath component, a specific arrangement is as follows: an outer side of the transitional component having the high content of the levo-isomer is coated with the transitional component having the low content of the levo-isomer.   
     
     
         4 . The preparation method for the polylactic acid fiber filter rod with better temperature resistance according to  claim 1 , wherein
 during carrying out step S 3 , the core component is matched with the sheath component according to the preset proportion, wherein the composition proportion of the core component to the sheath component ranges from 33:67 to 37:63.   
     
     
         5 . The preparation method for the polylactic acid fiber filter rod with better temperature resistance according to  claim 1 , wherein
 during carrying out step S 2 , a dispersing agent is added to the first component raw material   
     
     
         6 . The preparation method for the polylactic acid fiber filter rod with better temperature resistance according to  claim 1 , wherein
 during carrying out step S 2 , nucleating agents are respectively added to the first component raw material and the second component raw material.   
     
     
         7 . The preparation method for the polylactic acid fiber filter rod with better temperature resistance according to  claim 6 , wherein
 a percentage of the nucleating agent added to the first component raw material to the overall first component raw material is not lower than a percentage of the nucleating agent added to the second component raw material to the overall second component raw material; and   a difference between the percentage of the nucleating agent added to the first component raw material to the overall first component raw material and the percentage of the nucleating agent added to the second component raw material to the overall second component raw material does not exceed 5%.   
     
     
         8 . The preparation method for the polylactic acid fiber filter rod with better temperature resistance according to  claim 1 , wherein
 during carrying out step S 2 , before the core component is obtained by the crystallization of the first component raw material, it is ensured that the first component raw material is dispersed evenly; and before the sheath component is obtained by the addition of the glyceryl triacetate to the second component raw material, it is ensured that the second component raw material is dispersed evenly.   
     
     
         9 . The preparation method for the polylactic acid fiber filter rod with better temperature resistance according to  claim 3 , wherein
 nucleating agents are added to the plurality of transitional components, and a proportion of the nucleating agent to the transitional component having the low content of the levo-isomer is lower than a proportion of the nucleating agent to the transitional component having the high content of the levo-isomer.   
     
     
         10 . The preparation method for the polylactic acid fiber filter rod with better temperature resistance according to  claim 1 , wherein
 after carrying out step S 4 , the polylactic acid filter rod is cut using an alloy knife.