PROCESS FOR PRODUCTION OF POLYESTER RESIN POWDER, PROCESS FOR PRODUCTION OF POLYESTER PREFORMS AND THERMAL TREATMENT EQUIPMENT FOR POLYESTER RESIN POWDER

摘要

A process for the production of polyester resin powder which comprises charging polyester resin powder into plural treatment tanks and bringing heated gas into contact with the polyester resin powder to conduct the heat treatment of the powder, wherein (a) the step of charging a fixed amount of polyester resin powder into each treatment tank, (b) the step of feeding heated gas into the treatment tank for a certain time to carry out the heat treatment of the polyester resin powder, and (c) the step of discharging the treated resin powder from the tank are successively carried out repeatedly with phase difference among the tanks. According to the process, the resin powder can be efficiently heat-treated to give a product having further homogenized quality.