Method for thickening a polyester resin

摘要

A polyester resin is thickened in a chamber 4 by first introducing the feed resin through a port 2 and dehydrating in a drying section 14 under reduced pressure. A chemical agent is then added to the dehydrated feed resin and mixed therewith in a thickening section 15. The mixing occurs while deaerating under reduced pressure. The chemical agent functions to either increase the viscosity of the feed resin or suppress the lowering thereof.