| 摘要 |
PURPOSE:To produce a polyester of uniform quality, by measuring the specific resistance of a prepolymer or polymer in a molten state during the stage from the time of completion of the prepolycondensation reaction to the time of polymer discharge, and maintaining the specific resistance in a definite range. CONSTITUTION:A portion of a prepolymer or polymer in a molten state which finished the prepolycondensation is led, by a constant-rate pump 3, through a branch 2 provided in a sampling pipe 1 to a flow-type cell 4, wherein the specific resistance of the sample is determined by applying a voltage, using a voltage generator 7, between two platinum electrode plates 9 secured on a ceramic support 8 and detecting the produced electric current by an ammeter 6. The measured value is sent as a feedback and 30-400ppm (in terms of metal atom) of at least one metal compound selected from the group consisting of alkali (alkaline earth) metal compounds, and Mn compounds and/or P compounds having a metal/P atomic ratio of 1.0-2.0 are added so that the specific resistance may be maintained within a definite range.
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