Patent ID: 7807728

Claim:
A process for recycling recovered polycondensation polymer products, comprising supplying a recovered polycondensation polymer in a molten state having a changing input viscosity to a polymerization vessel having a porous plate, ejecting the recovered polycondensation polymer through pores of the porous plate, dropping the recovered polycondensation polymer through the polymerization vessel along a support, and increasing a polymerization degree of the recovered polycondensation polymer in the polymerization vessel under reduced pressure or in an inert gas atmosphere under reduced pressure; wherein melt viscosity of the recovered polycondensation polymer is continuously measured as the recovered polycondensation polymer is being supplied to the polymerization vessel, the reduced pressure in the polymerization vessel is continuously adjusted based on the melt viscosity to accommodate the changing input viscosity of the recovered polycondensation polymer, and the melt viscosity is measured upstream from the polymerization vessel.