| 摘要 |
PROBLEM TO BE SOLVED: To obtain a blow molding made from an easily moldable copolymer polyethylene naphthalate and having improved heat resistance, gas barrier properties, impact resistance, and light resistance by using a copolymer polyethylene naphthalate prepared by copolymerizing a polyethylene naphthalate with 2,6-decalindicarboxylic acid. SOLUTION: Naphthalenedicarboxylic acid and/or its lower alkyl ester and 1-10 mol% 2,6-decalindicarboxylic acid of the formula and/or its lower alkyl ester are polycondensed with ethylene glycol under heating to obtain a copolyethylenenaphthalate having an intrinsic viscosity of 0.60 or above, desirably, 0.65 or above. A preform obtained by injection-molding the copolymer polyethylene naphthalate is placed in a specified mold and oriented and blow- molded at a temperature higher than the secondary transition point of the polymer by 10-70 deg.C to obtain a blow molding having a failure rate of 10% or below (in a drop impact test), a color change of 8 or below in terms of a b value (in a light resistance test), an acetaldehyde content of 30 ppm or below, a haze of 5% (in a test on the body), and a body thickness of 200-500μm. In the formula, R is H or a lower alkyl. |
