| 摘要 |
Disclosed are polyester pellets made of a polyester which comprises dicarboxylic acid constituent units derived from dicarboxylic acids containing terephthalic acid and isophthalic acid and diol constituent units derived from diols containing ethylene glycol and 1,3-bis(2-hydroxyethoxy)benzene, and which has the properties: constituent units derived from terephthalic acid are 15 to 99.5% by mol and constituent units derived from isophthalic acid are 0.5 to 85% by mol, both based on the total amount of dicarboxylic acid isophthalic acid constituent units (i); constituent units derived from ethylene glycol are 25 to 99.5% by mol and constituent units derived from 1,3-bis(2-hydroxyethoxy)benzene are 0.5 to 75% by mol, both based on the total amount of the diol constituent units (ii); the intrinsic viscosity is in the range of 0.5 to 1.5 dl/g; and the melting point (Tm (°C.)), as measured by a differential scanning calorimeter, satisfies the formula [1/527-0.0017.ln(1-(mI+mB)/200)]-1-273<Tm<=265; said polyester pellets having a density of not less than 1,350 kg/m3. Also disclosed is a process for preparing the polyester pellets. The polyester pellets are excellent in gas barrier properties, transparency and heat resistance and hardly generate acetaldehyde.
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