JPH038567Y2 - - Google Patents

Description

[Detailed Description of the Invention] (Industrial Application Field) The present invention relates to a plastic bottle with an improved bottom shape.

(Prior art) The bottom shape of the plastic bottles widely used today is devised so that they can stably stand on their own.The bottom wall bulges inward of the plastic bottle and the surrounding area is used as a grounding surface. Furthermore, as shown in JP-A-54-16283, for example, the bottom wall was bent to form a plurality of hollow ribs extending radially from the center of the bottom wall to improve the strength of the bottom part.

(Problems to be Solved by the Invention) The present invention provides a plastic bottle with a further improved bottom shape.

(Means for Solving the Problems) The present invention will be described in detail below with reference to the accompanying drawings.

FIG. 1 is a partially cutaway front view showing an example of the plastic bottle of the present invention, and FIG. 2 is a bottom view of the plastic bottle of FIG. 1.

As shown in FIGS. 1 and 2, the present invention makes the bottom wall 2 of the plastic bottle 1 bulge inward, and
A plurality of hollow ribs 3 are formed extending radially from the center of the bottom wall, and the arrangement of the hollow ribs 3 is a mixed arrangement of ribs with short distances from the center and long ribs, with the vicinity of the center of the bottom being closer to the outer periphery. This is a plastic bottle characterized by the fact that it can hold many bottles.

The plastic bottle of the present invention is made by blow molding a tubular preform made of various types of plastic. Particularly preferred is a biaxially stretched blow-molded saturated polyester such as polyethylene terephthalate, which has excellent strength.

The bottom wall 2 bulges inwardly into the plastic bottle, as shown in FIG. 1, to counteract the stresses exerted by the contents.

The hollow ribs 3 protrude further inward from the bottom wall 2 as shown in FIG. 1, and are formed radially from the center of the bottom wall toward the periphery as shown in FIG. As shown in FIG. 2, the hollow ribs 3 are arranged in a mixed manner, with ribs 31 having short distances from the center and ribs 32 having long distances. Therefore, both the short ribs 31 and long ribs 32 are densely arranged near the center of the bottom wall 2, and the short ribs 31 are discontinued and only the long ribs are arranged near the outer periphery of the bottom wall 2. , there are more pieces near the center of the bottom than on the outer periphery.

As a result, the area near the center of the bottom wall is sufficiently reinforced by the densely arranged hollow ribs 3, and since the area near the center is the part that is most difficult to stretch when blow molding a tubular parison, the hollow ribs 3 prevent a large number of unevenness. Even if it occurs, it will not become too thin.
On the other hand, the outer peripheral part of the bottom wall can be reinforced by long ribs 32 up to the vicinity of the ground contact part 21, and since the long ribs 32 are sparsely arranged and there are few irregularities, the parts that are originally susceptible to bending become too thin. Therefore, the ground plane 21 will not become weak. Therefore, the strength of the entire bottom wall can be improved very efficiently.

For crystalline plastic bottles made of saturated polyester, in addition to the above-mentioned effects, the center area of the bottom wall, which is difficult to stretch, is sufficiently stretched and the heat resistance is improved by oriented crystals, and further heat treatment is applied to crystallize the bottle. Also, there is no risk of whitening or reduction in impact strength due to spherulites, and sufficient heat resistance can be provided to the bottom wall.

The long rib 32 extends from the bottom wall 2 as shown in FIG.
If the long ribs 32 are extended to the body 11 side of the plastic bottle so as to cross the contact surface 21 of the plastic bottle so that the long ribs 32 are visible from the outside when the plastic bottle is placed on a horizontal surface, it is possible to It can be used as a positioning target during quality inspection.

In the example shown in FIGS. 1 and 2, three short ribs 31 and three long ribs 32 are alternately and evenly arranged, but the number is not limited to this.

Furthermore, the hollow ribs 3 may protrude inward from the plastic bottle as in this example, but they may also protrude outward.

(Effects of the invention) The invention consists of making the bottom wall of a plastic bottle bulge inward and forming a plurality of hollow ribs extending radially from the center of the bottom wall. This plastic bottle is characterized by a mixed arrangement of short ribs and long ribs, with more ribs near the center of the bottom than around the outer periphery. The bottom wall can be sufficiently stretched by the long ribs, can be reinforced by the long ribs to the outer periphery, and the entire bottom wall can be reinforced very efficiently without the ground contact part being stretched too much and becoming thin.

[Brief explanation of the drawing]

FIG. 1 is a partially cutaway front view showing an example of the plastic bottle of the present invention, and FIG. 2 is a bottom view of the plastic bottle of FIG. 1. 1...Plastic bottle, 2...Bottom wall, 3...
...Hollow rib, 31...Short rib, 32...Long rib.

Claims (1)

[Scope of utility model registration request] The bottom wall of the plastic bottle is made to bulge inward, and a plurality of hollow ribs are formed radially extending from the center of the bottom wall. A plastic bottle characterized by a mixing arrangement in which there are more bottles near the center of the bottom than at the outer periphery.