| 摘要 |
<p>PURPOSE:To obtain a plastic container to be easily seamed with metal cover, which is excellent in mechanical strength for mouth and bottom portions in particular, by forming a preliminarily molded thermoplastic hollow molding into a container having a step difference on its torso portion by biaxial drawing hollow molding method. CONSTITUTION:A preliminary hollow molding is stretched 3-5 times in the crosswise direction and also 1.5-3 times in the longitudinal direction preferably by biaxial drawing hollow molding to obtain a container 2 having a step difference portion A-A' is cut off to obtain the biaxially stretched step-difference cut portion as the mouth of the plastic can. If the draw ratio is less than 1.5 times and also less than 3 times, can having excellent mechanical strength could not be obtained and uniform thickness could also not be obtained. If the draw ratio exceeds 3 times and 5 times, container, praticularly step difference portion, having exact shapeliness can not be obtained.</p> |
