| 摘要 |
<p>PURPOSE:To manufacture a container in which its pressure and heat resistance at the time of heating sterilization of its content is enhanced by setting the surface area of a thermally crystallized part of the center of the bottom of a vessel body to 0.2-15% of the sectional area of the maximum body of the container. CONSTITUTION:The center of the bottom and the neck 3 of a container which is not sufficiently oriented at the time of stretch blow molding are so thermally crystallized without stretching that the thermally crystallized surface area of the center of the bottom is particularly set to 0.2-15% of the sectional area of the maximum body of the container as a thermally crystallized part. After the whole part except the crystallized part is heated in advance to 70-140 deg.C, it is stretched by a high stretching magnification, its body 8 is crystallized 15-40% in crystallization rate, the parts which are difficult to be crystallized such as the circular-arc part of the bottom adjacent to the center of the bottom, the upper shoulder part 6 adjacent to the neck are crystallized 10-30% to eliminate the regions which are not crystallized, thereby enhancing heat and pressure resistances.</p> |
