Method for preparing pet/ptt parallel complex filament with high self-crimpiness

A method for preparing a PET/PTT parallel complex filament with high self-crimpiness, comprising:

• PET and PTT are sliced, dried and crystallized, and then fused separately and subjected to extrusion molding through a parallel-type spinneret plate;
• oil is applied after cooling;
• level 1-3 drafting and heat setting treatment are conducted;
• wherein a total drafting rate is controlled at 3 to 3.5, wherein the level-1 drafting rate is 2.8 to 3.0 at a temperature controlled to 75 to 80° C., and the drafting rates of remaining levels are 1.0 to 1.5 respectively at a temperature of 75 to 80° C.;
• the drafted filaments are subjected to dynamic heat setting treatment to obtain the PET/PTT parallel complex filament with high self-crimpiness, wherein an intrinsic viscosity of the PET raw material is 0.60 to 0.65 dL/g, an intrinsic viscosity of the PTT raw material is 0.90 to 0.96 dL/g, and a spinning temperature of the spinning molding is 270 to 275° C.;
• a wherein winding rate of the fiber is 3600 to 3900 m/min;
• wherein during the dynamic heat setting treatment that the filament is wound on a rotating heat roller or passed through a high-temperature hot plate;
• and the dynamic heat setting is performed at a temperature of 152 to 156° C. for 20s to 30s.