Patent ID: 6814939
Filing Date: 2004-11-09
Classification: D01F,D21F,Y10T

Abstract:
An apparatus for solid phase polymerizing polymer flake having a polyamidation catalyst dispersed within the flake and a formic acid relative viscosity of about 40 to about 60 by contacting the flake with substantially oxygen free inert gas, comprising:a solid phase polymerization assembly for increasing the relative viscosity of the flake, the assembly having: a vessel with a flake inlet for receiving the flake, a flake outlet for removing the flake after being solid phase polymerized, a gas inlet for receiving the gas, and a gas outlet for discharging the gas; and a gas system for circulating the gas through interstices between the flake in the vessel, the gas system having: a filter for separating and removing dust and/or polymer fines from the gas, a gas blower for circulating the gas, a heater for heating the gas, and a first conduit connecting, in series and in turn, the gas outlet, the filter, the blower, the heater, and the gas inlet; and a serially connected dual desiccant bed regenerative drying system connected in parallel with the first conduit between the blower and the gas inlet, the drying system for lowering the dew point temperature of at least a portion of the circulating gas such that the dew point temperature of the gas at the gas inlet is no more than about 20Â° C., whereby solid state polymerization of the flake occurs increasing its formic acid relative viscosity while the gas is circulated through interstices between, thereby contacting, the flake in the vessel at a temperature of about 120Â° C. to about 200Â° C. for about 4 hours to about 24 hours, after which flake having a formic acid relative viscosity of at least about 90 can be removed from the flake outlet.