Waste plastic conditioning and viscosity modifying system

The invention relates to a reaction system for polymers in chemical fiber industry, in particular to a waste plastic conditioning and viscosity modifying system, which comprises a vacuum separation tower (1), wherein a raw material inlet (3) and a vacuum opening (2) are formed above the vacuum separation tower (1); a discharge opening (6) is formed below the vacuum separation tower (1); the outside surface of the vacuum separation tower (1) is provided with a hot medium coil (4); porous plates (5) are arranged at intervals in the vertical direction in the vacuum separation tower (1); and the discharge opening (6) is also connected with a two-stage conditioning and viscosity modifying device. With the additional two-stage conditioning and viscosity modifying device with a screw arranged inside, raw material can be pushed and stirred to improve viscosity; a vacuum pump is adopted to further improve vacuum degree, and a reaction environment is provided for improving the viscosity of the raw material; and the combination of the factors promotes the obvious improvement on the production efficiency of high-viscosity poly(ethylene terephthalate) (PET) plastic raw material.