| 摘要 |
<p>PROBLEM TO BE SOLVED: To provide a bottom part structure of a plastic bottle body reducing the strain generated in the bottom part of the bottle body at a time of molding at proper temp. and hard to generate deformation with the elapse of time and thermal deformation. SOLUTION: The bottom part 2 of a plastic bottle body 1 molded from a primary molded product preform by biaxial stretch blow molding is equipped with the annular bottom wall part 4 continuing to a body part 3, the projected bottom wall part 5 projected into the body part 3 in a semisphirical shape from the inner peripheral edge of the annular bottom wall part 4 along the center axial line 1a of the bottle body and a recessed bottom wall part 6 formed by depressing the top wall part of the projected bottom wall part 5 in a semispherical shape. The shape of the recessed bottom wall part 6 is allowed to substantially coincide with that of the leading end part of the bottom part of the preform. The state at a time of the molding of the preform is left in the bottom part of the bottle body easiest to generate thermal deformation of the plastic bottle body 1 as it is and the strain of the bottle bottom part at a time of blow molding is also reduced. Therefore, thermal deformation or deformation with the elapse of time is hard to generate.</p> |
