| 摘要 |
<p>PURPOSE:To obtain a bottle which is remarkably excellent in gas barrier properties and also has heat resistance by forming a preform from polyethylene naphthalate resin and performing high stretching for this preform at prescribed stretching index or more. CONSTITUTION:A preform for forming a bottle is obtained by molding polyethylene naphthalate resin obtained from e.g. 2,6-dinaphthalene dicarboxylic acid and ethylene glycol. Then a biaxially stretched bottle is obtained by molding the obtained preform with a molding machine. Further at this time, stretching index is regulated to >=130cm preferably 140-220cm to perform high stretching. Stretching index = inner volume (excepting cap stopper part) of stretched bottle/inner volume (excepting cap stopper part) of unstretched preform X1/f f = inner surface area (excepting inner surface area of cap stopper part) of stretched bottle/inner volume (excepting volume of cap stopper part) of stretched bottle (cm<-1>).</p> |
