POLYESTER BOTTLE WITH RESISTANCE TO HEAT AND PRESSURE AND PROCESS FOR PRODUCING THE SAME

摘要

A process for producing a heat- and pressure-resistant polyester bottle which comprises a primary blow molding step in which a preform of a polyester resin is subjected to biaxial stretching blow molding to obtain a primary molding, a heat treatment step in which the primary molding is heat-treated and thermally shrunk to obtain a secondary molding, and a secondary blow molding step in which the secondary molding is subjected to biaxial stretching blow molding to obtain a final molding. In the primary blow molding step, biaxial stretching is conducted so that the neck part of the primary molding has almost the same size as the neck part of the final molding. Furthermore, the heat treatment step is conducted so that the neck part of the secondary molding has undergone no thermal shrinking. Thus, a heat- and pressure-resistant polyester bottle can be provided in which the length of the neck part is in the range of 10-40% of the bottle height, the neck part has a crystallinity of 20-35%, and the barrel part has a crystallinity of 35-50%. It has a slender neck, i.e., it is a long-necked bottle, and is suitable for use as a beer container. This bottle made of a polyester resin does not impair the impression given by conventional glass-bottled beers.