POLYETHYLENE TEREPHTHALATE AND ITS USE

摘要

PURPOSE:To obtain polyethylene terephthalate improved in heat resistance and transparency and being useful for a preform for blow moldings and a blow- molded container by specifying the composition and properties of the polyethylene terephthalate. CONSTITUTION:For example, terephthalic acid is esterified with ethylene glycol, and the product is polycondensed to obtain polyethylene terephthalate having a composition composed of randomly arranged 97.0-98.6mol% ethylene terephthalate component units of formula I and 1.4-3.0mol% dioxyethylene terephthalate component units of formula II and having an intrinsic viscosity [eta]in o-chlorophenol of 0.70-0.90dl/g (at 25 deg.C), a crystallization temperature (Tcc) >=165.0 deg.C as determined by differential scanning calorimetry (with the rate of temperature rise of 10 deg.C/min) and in the range: 67.5 [eta]+119.0<=Tcc<=67.5[eta]+133.5.