| 摘要 |
PROBLEM TO BE SOLVED: To suppress an eccentricity of a central core material so as to prevent characteristic deterioration due to a large eccentricity of the material in the case of a final coating due to a superposition of eccentric directions intrinsic for a plurality of extruders, when multiple layers are coated on the central core material by the plurality of the extruders disposed in multi-stages. SOLUTION: A method for manufacturing a multilayer extrusion material comprises the steps of providing a turn wheel 31 forward of a crosshead 32 of the extruder 30, winding the central core material 20 on the wheel 31, then guiding the wheel 31 to the crosshead 32. When the wheel 31 is inclined and installed with a manufacturing line as an axis, the material 10 is twist rotated, and a thickness distribution of coating as seen from the core material can be changed. The method further comprises the steps of repeating twist rotating of the material 10 at the extruder of the rear stage as needed, thereby minimizing the eccentricity of the core material to the final coating. |
