PREPARATION METHOD OF POLYETHYLENE NAPHTHALATE-BASED POLYMER

摘要

PURPOSE: A method for preparing a polyethylene naphthalate-based polymer is provided, to minimize the amount of by-product by reducing the amount of ethylene glycol and to reduce the time of esterification, thereby improving the quality and the productivity. CONSTITUTION: The method comprises the steps of adding at least one kind of primary alcohol to a slurry comprising naphthalene dicarboxylic acid or dicarboxylic acid or its derivatives containing the acid as a main component, and ethylene glycol or glycol or its derivatives containing ethylene glycol as a main component, to esterify the slurry and to obtain an esterified product containing bis(β-hydroxyethyl)naphthalate or its oligomer as a main component; and polycondensing the mixture continuously to obtain a polyethylene naphthalate-based polymer. Preferably the dicarboxylic acid or its derivatives are 2,6-naphthalene dicarboxylic acid, terephthalic acid, 2,6-naphthalene dicarboxylic acid dimethylester, or dimethyl terephthalate; the glycol or its derivatives are ethylene glycol, 1,3-propane diol or 1,4-butane diol; and the primary alcohol is methanol, ethanol, n-propanol, isopropanol and n-butane diol.