| 摘要 |
PURPOSE:To obtain a bottle, which is not broken after long-term preservation under hot and humid conditions of soda drinks bottled by a method wherein longitudinal draw ratio, orientation temperature and blow timing are provided in the manufacturing of a bottle produced by blow-molding a preform made of saturated polyester. CONSTITUTION:Preferable saturated polyester is polyethylene terephthalate and, as its solvent, o-chlorophenol having the intrinsic viscosity [eta] at 25 deg.C of 0.50-1.0dl/g is used. Blow molding is performed under the condition that the longitudinal draw ratio is 110-350%, the orientation temperature is 80-110 deg.C or lower and the time since a preform is extruded till gas is blown is 0.1-1.0sec. When soda water is filled, sealed and, after that left for one month at 40 deg.C under the relative humidity of 90% in a bottle, which is produced under the conditions of the longitudinal draw ratio of 350% or more, the orientation temperature of 110 deg.C or higher and the blow timing of 1.0 sea or longer respectively, The incidence of crack in the bottle increases abruptly. Further, of a bottle and especially of its upper shoulder part 3, the preferable degree of orientation is 0.6 or less, the preferable orientation crystallinity index is 50% or less and the preferable wall, thickness is 0.25mm or more. |
