| 摘要 |
PURPOSE:To obtain a polyethylene 2,6-naphthalate film of excellent recyclability by specifying the intrinsic viscosity and terminal carboxyl content after melting under specified conditions. CONSTITUTION:The film has an intrinsic viscosity equal to at least 80% of that before meLting when it is melted under the conditions of a temperature of 300-330 deg.C and a melting time of 5-30min, and a terminal carboxyl content of below 100eq/10<6>g after melting. The starting polyethylene 2,6-naphthalate is obtained by reacting 2,6-naphthalenedicarboxylic acid (ester) with ethylene glycol to obtain bis-beta-hydroxyethyl 2,6-naphthalate (oilgomer) and polycondensing it by heating in a vacuum. |
