| 摘要 |
<p>PROBLEM TO BE SOLVED: To obtain a resin having a stable quality at a lower cost by recycling a polyester resin recovered from a waste product without a complicated process by directly feeding polyester resin recovered from a waste product to a polycondensation process in which a degree of polymerization shown by an intrinsic viscosity is at a specific stage. SOLUTION: A resin having stable quality is obtained with a minimum energy loss by feeding a recovered polyester resin at a stage when a degree of polymerization of a polyester from a virgin raw material is in a predetermined range, that is, an intrinsic viscosity thereof is 0.2 to 0.6 g/dl. The virgin raw material for the polyester is a polycarboxylic acid or an ester thereof (e.g. terephthalic acid) and the polyhydric glycol raw material is, for example, ethylene glycol or the like. The recovered polyester resin is stored in a closed vessel which is substituted with an inert gas such as nitrogen and then is directly fed to a reaction vessel under a reduced pressure.</p> |
