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, wherein 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;
• then level 1-3 drafting and heat setting treatment are adopted;
• and during drafting, a total drafting rate is controlled to be 3 to 3.5, wherein the level-1 drafting rate is 2.8 to 3.0 at a temperature controlled to be 75 to 80° C., and the drafting rates of the 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 a spinning molding is 270 to 275° C.;
• a winding rate of the fiber is 3600 to 3900 m/min;
• the dynamic heat setting refers that the filament is wound on a rotating heat roller or passed through a high-temperature hot plate to obtain transient setting;
• and the dynamic heat setting is performed at a temperature of 152 to 156° C. for 20s to 30s;
• wherein the PET/PTT parallel complex filament with high self-crimpiness has a monofilament linear density of 2 to 3 dtex, a breaking strength of 3.2 to 3.5 cN/dtec, a breaking elongation of 25 to 45%, an elastic recovery rate of 40 to 45%, and a crimping rate of 45 to 49%.