PURPOSE: To enhance transparency and heat shrinkage resistance by a method wherein cold parison, which is produced out of stock polyester having the specified repeating unit, is stretch-blow-molded under the specified conditions.
CONSTITUTION: Cold parison, which is made of polyester resin having 80mol.% or more of repeating unit or ester unit consisting of 1,3-propanediol and terephthalic acid or their ester-forming derivatives is blow-molded, resulting in manufacturing a bottle. In this case, the cold parison is stretched by blowing pressure fluid under the heating atmosphereling within the range: Tg-10≤Ta≤Tcc (°C) and, in succession, the resultant parison is heat-set in molds having the temperature range: Tcc≤Tb≤Tm in order to obtain the desired blown bottle, in which Ta is stretching temperature, Tb is the temperature of the molds and Tg, Tcc and Tm represent respectively the glass transition temperature, cold crystallization temperature and melting temperature of resin measured by means of the differential thermal analysis method on JIS K7121 at the temperature rise rate of 10°C/min.
NAKANE TOSHIO
HIJIKATA KENJI
