JPH0594112U - Square plastic bottle - Google Patents

Abstract

(57) [Summary] [Objective] The rigidity of the barrel wall is increased by improving the rib structure of the rectangular plastic bottle. [Structure] The rib 10 formed in the middle part of the body of the bottle is
The panel walls 2, 3, 4, 6 are formed deeper than the corner wall 6 so that the panel wall has ribs projecting stepwise into the bottle more than the corner wall. [Effect] The rigidity of the body is dramatically improved as compared with the conventional rectangular plastic bottle, and even if the bottle is made thin, it can be applied to a hot pack having a high filling temperature.

Description

[Detailed description of the device]

[0001]

[Industrial applications]

 The present invention relates to a rectangular plastic bottle with a reinforcing rib, and more particularly to a rib structure for improving the rigidity of its body.

[0002]

[Prior Art]

Conventionally, plastic bottles such as biaxially stretched polygonal PET bottles used for filling content liquids that require high-temperature sterilization such as fruit juice beverages have the following features in order to prevent thermal deformation and remove residual stress due to high-temperature filling. In addition to heat setting in the molding process, structurally shortening the straight part to improve the rigidity of the body wall, vertical and horizontal compression strength, and to prevent sinking of the bottle by heat setting, the bottle body One or more circumferential grooves (ribs) are formed in the middle portion (waist portion). The ribs are generally formed to have the same depth over the entire circumference, but by forming the ribs on each side deeper toward the central portion (Japanese Utility Model Laid-Open No. 1-164128). Alternatively, as shown in FIG. 6, by forming the depth d ₂ in the corner wall portion 25 to be shallower than the depth d ₁ in the panel wall portion 26 (No. Some proposals have been made to raise it further. As a result, the material will be made thinner and the cost will be reduced. However, in the case of hot pack filling, if the filling temperature is raised, the change in the internal volume after filling is large, and the change cannot be completely absorbed by the panel part, and the bottle rigidity decreases due to the reduced pressure state. However, it is difficult to make the bottle for high temperature filling thinner.

[0003]

[Problems to be solved by the device]

 Therefore, in the present invention, in the case of a rectangular bottle with a reinforcing rib, the rigidity of the bottle is further enhanced and the wall thickness is further reduced by further improving the structure of the rib previously proposed in Japanese Utility Model Laid-Open No. 2-102316. It is a technical issue to make it possible to obtain a thinner plastic bottle that can maintain sufficient rigidity even when hot packed.

[0004]

[Means for Solving the Problems]

 In order to solve the above-mentioned problems, the prismatic plastic bottle of the present invention is a plastic bottle in which ribs are formed in a circumferential groove shape in an approximately middle portion of a substantially rectangular tubular body. The problem can be solved by adopting a technical means characterized in that the rib is formed deeply and the rib in the panel wall portion is projected stepwise into the bottle more than the rib in the corner portion.

[0005]

[Action]

 Generally, the rigidity of the body part increases as it becomes deeper as it relates to the depth of the circumferential groove ribs provided on the waist part of the bottle, but in the case of a rectangular bottle, if the ribs have a uniform depth all around the body part. It is recognized that the strength around the entire circumference of the body is not uniform and the buckling strength is weakened. The present inventor has found a rib structure having the above-mentioned structure as a result of various experiments in order to obtain a rib structure effective for improving the rigidity of the bottle body. As a result, the rigidity of the bottle body was dramatically improved, the deformation of the bottle was small even during hot pack filling, where the filling temperature was high, and the wall thickness of the bottle was made thinner than before.

[0006]

【Example】

Embodiments of the present invention will be described below with reference to the drawings. 1 and 2 show an embodiment of a plastic bottle according to the present invention, which is applied to a bottle that is biaxially stretch-molded with polyethylene terephthalate resin and has a substantially rectangular cross section with a wide width with respect to the depth. Showing. The body portion of the bottle 1 is formed of a panel wall portion including a front wall 2, a rear wall 3, a right side wall 4 and a left side wall 5, and a corner wall portion 6 formed by cutting four corners. ing. A rib 10 is formed in the middle of the body. The rib 10 has a depth f ₁ at the panel wall portion that is deeper than a depth f ₂ at the corner wall portion 6 with respect to the outer peripheral surface of the bottle body, and as shown in FIG. The rib inner peripheral surface of the rib portion projects inwardly in a stepped manner from the rib inner peripheral surface of the corner wall portion. In this structure, the rib of the corner wall portion is formed shallower than the rib of the panel wall portion as shown in FIG. 6, and the rib of the panel wall portion is further formed in a stepped shape so as to project inwardly of the bottle. It is equivalent to the above-mentioned one, and by doing so, the rigidity of the body has been dramatically improved compared to the conventional one. Further, in this embodiment, in order to more effectively absorb the deformation of the body portion due to the hot pack filling and increase the rigidity, several grooves 11 are formed in the upper center portion separated by the ribs of the front wall and the rear wall. The deformable portion 12 is formed, and a plurality of ribs 13 are formed on the entire body.

In order to confirm the effect of the present invention configured as described above, the rib depth of the panel wall is set to be 1 mm more than that of the conventional example shown in FIG. 6 for the front wall, the rear wall, the right side wall and the left side wall. The deeply formed embodiment of the present invention and a conventional example (comparative example 1) as shown in FIG. 6 as a comparative example, and the depth of the rib 10 as shown in FIG. 3 (a) is only the front wall 31 and the rear wall 32. The one formed 1 mm deeper than the others (Comparative Example 2) and the one having both side walls 33 and 34 formed 1 mm deeper than the others (Comparative Example 3) as shown in FIG. Rigidity test was performed. Each of the bottles was filled with water until it reached 54 mm below the top of the bottle mouth, and the rise in the liquid level filled inside when the lateral pressure of 1 to 5 kg / cm ² was applied to each body was measured. The measurement results are shown in Table 1. The amount of change at that time is shown in FIG.

[Table 1] (Unit: mm)

As is clear from the test results, it is confirmed that the liquid level rise in each lateral pressure is small in this embodiment, that is, the amount of change is small and the rigidity of the body is considerably improved, as compared with the conventional example. It was On the other hand, as in Comparative Examples 2 and 3, when only the front and rear walls or the left and right side walls of the panel wall portion are deepened, the rigidity as a whole tends to be improved as compared with the conventional example. In the case of only the wall, the lateral pressure acts in a high range, and in the case of only the left and right walls, the low side pressure acts in the opposite range. The above objective has not been completely achieved.

FIGS. 4 and 5 relate to a plastic bottle with a reinforcing rib according to another embodiment of the present invention applied to a plastic bottle having a substantially square cross-section, and the bottle 15 has a substantially central portion of the body. The structure of the rib 16 formed on the front wall 17, the rear wall 18, the right side wall 19 and the left side wall 20 is deeper than the corner wall portion 21.

[0010]

[Effect of the device]

 INDUSTRIAL APPLICABILITY The present invention has a remarkable effect that the rigidity of the body can be dramatically improved as compared with the conventional rectangular plastic bottle with the above-mentioned simple structure. As a result, the wall thickness of the bottle can be made thinner than before, and it can have sufficient rigidity even when applied to a hot pack with a high filling temperature, reducing the material cost of the bottle and reducing the bottle cost. The weight can be reduced.

[Brief description of drawings]

1A is a front view of a rectangular plastic bottle according to an embodiment of the present invention, and FIG. 1B is a side view thereof.

FIG. 2 is a sectional view taken along line AA of FIG.

3A is a cross-sectional view corresponding to FIG. 2 when only the ribs of the front and rear walls are formed deep as a comparative example, and FIG. 3B is equivalent to FIG. 2 when only the ribs of left and right walls are formed deep as a comparative example. FIG.

FIG. 4 is a front view of a rectangular plastic bottle according to another embodiment of the present invention.

5 is a sectional view taken along line BB of FIG.

FIG. 6 is a cross-sectional view of a conventional rectangular bottle corresponding to FIG.

FIG. 7 is a graph showing a change amount of a bottle with respect to lateral pressure in a lateral rigidity test of the bottle.

[Explanation of symbols]

 1, 15 Body part 2 Front wall 3 Rear wall 4 Right side wall 5 Left side wall 6 Corner wall part 10, 16 Rib

Claims (1)

[Scope of utility model registration request] 1. A prismatic plastic bottle in which ribs are formed in a circumferential groove shape in a substantially middle portion of a substantially rectangular tube-shaped body portion, wherein a depth of the rib in a panel wall portion is formed deeper in a corner portion, A prismatic plastic bottle, wherein the ribs in the panel wall portion project in a stepped manner into the bottle from the ribs in the corner portions.