POLYETHYLENE TEREPHTHALATE CAPABLE OF PREVENTING FAULTY APPEARANCE DERIVED FROM A CYCLIC TRIMER WHILE HAVING SUITABLE INHERENT VISCOSITY FOR MANUFACTURING A FILM AND A MANUFACTURING METHOD THEREOF

摘要

PURPOSE: A polyethylene terephthalate is provided to have low inherent viscosity, to reduce the content of a cyclic trimer, and to have excellent color (b value).;CONSTITUTION: A polyethylene terephthalate contains 30-70 ppm of a germanium metal. The inherent viscosity of the polyethylene terephthalate is 0.62-0.67 dl/g, the cyclic trimer content is 0.34 wt% or less, the nitrogen content is 2 ppm or less, each of the Si and Al contents is 1 ppm or less, and the color (b value) is 1 or less. A manufacturing method of the polyethylene terephthalate includes a liquid phase polycondensation process which manufactures a polymer by liquid phase polymerizing a terephthalic acid-containing aromatic dicarbonic acid or the ester-forming derivative thereof and an ethylene glycol-containing aliphatic diol or the ester-forming derivative thereof under the presence of a germanium compound as a polymerization catalyst; and a solid phase polycondensation process which changes the inherent viscosity of the polymer and the cyclic trimer.;COPYRIGHT KIPO 2013