The invention relates to an extruder for preparing fusible polymers by tackifying modification. An extruder screw with at least one helical screw thread (31, 32, 33, 34, 35) is installed inside a shell with inner shell grooves. The outer diameter of the extruder screw is divided into a starting diameter section, a central diameter section and an ending diameter section (21, 22, 23). The central diameter section has a larger outer diameter D2 than at least one of the other diameter sections (21, 25), and tapered transition zones (22, 24) are respectively formed between sections with different diameters D1, D2 and D3. Two degassing zones (23.1, 23.3) are arranged in the central diameter section, each equipped with at least one corresponding suction port on the shell. One degassing zone (23.3) is arranged in the area of the satellite screw, and the other degassing zone (23.1) is arranged upstream in the material flow direction. In the two degassing zones (23.1, 23.3), the thread depth of the screw threads (42, 43, 44) formed between the extruder screw threads (32, 33, 34, 35) is greater than that of at least one sealing and compression section (23.2) therebetween.

Area Code: DE

Application Number: CN202080051893.6