| 摘要 |
PURPOSE: Provided is a solid state polymerization of copolyester, wherein the copolyester produced by the solid state polymerization has a uniform high intrinsic viscosity and is excellent in color and formability, therefore can be used for preparing bottles, sheets, and industrial raw thread. CONSTITUTION: The solid state polymerization is performed by crystallizing, pre-heating, solid state-polymerizing, and cooling copolyester chips having an intrinsic viscosity of 0.5-0.7 produced by copolymerizing naphthalene dicarboxylic acid, isophthalic acid, or ester-formable derivatives thereof, wherein the copolyester chips are pre-crystallized, before the solid state polymerization, at 80-100deg.C for 10-30 minutes in hot water to make a surface crystallinity 3-10%. The solid state-polymerized copolyester has an intrinsic viscosity of 0.8-1.5.
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