Multi-shaft extrusion of recycled polycondensates to produce granules involves limitation of the period in which the polycondensate remains molten

摘要

The polycondensate is melted in the extruder and the total time during which its temperature lies above the melting point is limited to /}60 seconds to avoid hydrolytic reaction due to the relatively high water content. Preferred Features: When the time period above the melting point is /}30 seconds melt with a residual water content of >= 200ppm can be processed with little loss in intrinsic viscosity.