PURPOSE: To prevent injury of appearance due to deformation by a method wherein an upper part of a container body on an open end side is molded in a substantially oblong cylinder having a prescribed height with respect to the entire height of the container without vertical ribs, a lower part of the container body is molded in a shape the cross section of which is a substantially right polygon consisting of a plurality of vertical ribs and panel faces between the ribs, and the respective ribs are formed to be thicker than the panel faces.
CONSTITUTION: In a plastic container, a lower body part has a cross section of a right polygon, the container 1 consists of a body 2 and a bottom part 3, and the body 2 consists of an upper body part 4 shaped in a substantial cylinder and the lower body part 4 shaped in a right octagon. The height (h) of the substantially cylindrical upper body part 4 is set to one third or less of the entire height (H) of the container 1, because if the height (h) is too high with respect to the entire height (H), the length of a varietal rib 10 becomes too short to retain the strength of the container 1. If the number of the vertical ribs 10 is increased, the strength against load from the lateral direction of the container 1 cannot be retained, and therefore it is preferable to set the number of the ribs 10 to a dozen or less. On the contrary, if the number of the vertical ribs 10 is too small, the strength against the load from the vertical direction of the container 1 cannot be retained and the container 1 is likely to deform inward or outward, and therefore it is preferable to set the number of the ribs 10 to half of dozen or more.
TAKAHASHI KUNIMITSU
OGASAWARA MASARU
NAKADA AKIRA
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