The invention discloses high-strength
slurry-free
polylactic acid (PLA)
yarn and a preparation method thereof. The high-strength
slurry-free PLA
yarn is formed by PLA staple fibers with the
linear density of 1.3-7.7 dtex and the length of 25-150 mm; and the PLA staple
fiber is provided with a
skin-core structure, a
skin layer is low-melting-point PLA, a core layer is high-melting-point PLA, and amass ratio of the
skin layer to the core layer is 5: 90-50: 50. The preparation method of the high-strength
slurry-free PLA
yarn comprises the following steps of
drying raw materials of the skin layerand the core layer, respectively adding the raw materials into a hopper corresponding to a composite
spinning machine, and carrying out melt conveying,
spinning,
air blast cooling, winding and feeding,
oil bath stretching,
steam bath stretching, tension
heat setting, oiling, laminating,
curling, loosening, and
cutting processes to obtain the PLA staple
fiber of the skin-core structure; and carrying out
spinning with the PLA staple fibers of the skin-core structure as the
raw material in order to prepare the PLA yarn, enabling the PLA yarn to pass through a pair of heating rollers and carryingout heating and pressure treatment on the PLA to prepare the high-strength slurry-free yarn, wherein the
heating temperature is higher than the
melting point of the PLA of the skin layer and is lowerthan the
melting point of the PLA of the core layer; through the adhesion effect of the skin layer, the hairiness is reduced, the cohesive force between the fibers is increased, and the high strengthand free slurry of the yarn are realized. The prepared high-strength slurry-free PLA yarn can be used in the fields of textiles for clothing, textiles for decoration and industrial textiles.