| 摘要 |
PURPOSE: Provided is a method for the solid-state polymerization of polyethyleneterephthalate, which enhances the polymerization productivity due to the reduction for the difference of polymerization degree between the surface and inside of PET pellets, and the improvement of the overall polymerization degree and the polymerization rate. CONSTITUTION: The method for the solid-state polymerization of polyethyleneterephthalate with high degree of polymerization comprises the steps of: crystallizing polyethyleneterephthalate pellets having the polymerization IV value of 0.6 dl/g or less, then subjecting them to primary solid-state polymerization, compressing the resultant mechanically and then subjecting them to secondary solid-state polymerization at a temperature of 200-230 deg.C to prepare polyethyleneterephthalate having the IV value of 0.9 dl/g or more.
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