| 摘要 |
PROBLEM TO BE SOLVED: To provide an industrially useful method for efficiently producing a higher molecular weight polyethylene terephthalate by thermally treating polyethylene terephthalate prepolymer particles to polycondensate it in a solid phase with a high polycondensation reaction rate without fusion of the particles. SOLUTION: The method for producing a polyethylene terephthalate includes raising its intrinsic viscosity by at least 0.30 dL/g by thermally treating a polyethylene terephthalate prepolymer having an intrinsic viscosity of >0.40 dL/g but≤0.80 dL/g in a solid state, wherein the thermal treatment in solid state comprises a first solid phase polycondensation process, a rapid temperature-rising process and a second solid phase polycondensation process in this order. COPYRIGHT: (C)2010,JPO&INPIT
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