Preparation method of coarse-denier non-crimp dumbbell-shaped full-dull polyester staple fiber

The invention relates to a preparation method of heavy denier non-crimp dumbbell-shaped full-dull polyester staple fibers, which comprises the following steps: drying full-dull polyester chips, melting by a screw extruder, spinning by a dumbbell-shaped special-shaped hole spinneret plate, carrying out short-distance air blowing cooling by an annular blowing cylinder, winding and falling into a barrel to prepare protofilaments; performing post-spinning bundling, first-stage oil bath drafting, second-stage steam drafting, tension heat setting, stacked fiber oiling and cutting on the protofilament to obtain the coarse-denier non-crimp dumbbell-shaped full-dull polyester staple fiber, wherein the coarse-denier non-crimp dumbbell-shaped full-dull polyester staple fiber is obtained; the diameter of the spinneret plate with the dumbbell-shaped special-shaped holes is 220mm, the length of the dumbbell-shaped special-shaped holes is 2.2 +/-0.025 mm, the dumbbell-shaped special-shaped holes point to the center of the s