JPH08217043A - Pressure-resistant plastic bottle - Google Patents

Abstract

PURPOSE: To suppress the deformation of a leg part, prevent the standing attitude of a bottle from becoming unstable by the inward movement of grounding points, and also prevent a crazing from generating by forming a recessed part which is adjacent to the bottle central side of the leg grounding part being formed on the bottom of a body part, and forms a part of the spherical surface. CONSTITUTION: A plurality of leg parts 2 for which the lowest end part of a bottom part 12 being connected to a body part is made the grounding part 21 are formed with equal intervals on the peripheral end part of the bottom part 12, and a bottom surface 22 with an upward gentle tilt toward the center of the bottle is formed continuing from the grounding parts 21 for a pressure plastic bottle 1. For such a pressure plastic bottle 1, a recessed part 3 which forms a part of the spherical surface is formed to be adjacent to the grounding part 21 on the bottle central side. When a carbonated beverage, etc., are filled in the plastic bottle, and a large internal pressure is applied to the bottom part 12 due to the action of carbon dioxide, etc., stresses in the axial direction, diametrical direction and peripheral direction of the bottom surface of the leg part 2 act, and by a reinforcing effect of the recessed part 3 which forms a part of the spherical surface, the grounding points move inward, and prevent the standing attitude of the bottle from becoming unstable.

Description

Detailed Description of the Invention

[0001]

FIELD OF THE INVENTION The present invention relates to a pressure resistant plastic bottle having a pressure resistant bottom.

[0002]

2. Description of the Related Art A pressure-resistant plastic bottle filled with beer, carbonated drinking water, etc. is formed by biaxially stretch blow molding a saturated polyester resin such as polyethylene terephthalate as shown in the front view of FIG. 13, a shoulder portion 14 connected to it, a body portion 11 and a pressure-resistant bottom portion 12
Those having are widely known.

As the pressure-resistant shape of the bottom portion, a plurality of leg portions 2 whose bottom end portion is a ground portion are formed at equal intervals on the peripheral end portion of the bottom portion 12 connected to the body portion 11. The shape of the outer wall 23 is continuous with the body, the lowermost grounding portion 21 of the outer wall, the side wall 24 formed on both sides of the grounding portion, and the grounding portion are connected to the grounding portion and faced upward toward the center of the bottle. It has a basic shape with a gently sloping bottom surface 22.

As shown in the bottom view of the leg portion of the conventional pressure-resistant plastic bottle in FIG. 4, the shape of the bottom portion of the bottle is expanded and deformed by the action of the internal pressure, and the grounding point moves inward to raise the bottle. It is also known that the recess 3 is provided on the entire bottom surface 22 of the leg 2 in the longitudinal direction in order to prevent the instability. (Actual fair 2-1222)

[0005]

Since the bottle is provided with a recess in the entire bottom surface of the leg in the longitudinal direction, the shape of the bottom of the bottle, particularly the leg, expands and changes in the axial direction and the radial direction. Although it is effective in suppressing this, there is a problem that crack-like crazing is likely to occur at the bottom of the bottle due to the internal pressure.

[0006]

SUMMARY OF THE INVENTION The present invention solves the problems of the conventional pressure-resistant plastic bottles described above and obtains further excellent pressure resistance, and its gist is the peripheral end portion of the bottom portion connected to the body portion. In the pressure-resistant plastic bottle, a plurality of legs having the lowermost end as a grounding portion are formed at equal intervals, and a bottom surface is formed in a gentle slope that is continuous with the grounding portion and that faces upward toward the center of the bottle. The pressure-resistant plastic bottle is characterized in that a concave portion forming a part of a spherical surface is formed adjacent to the center side of the grounding portion of the bottle.

The present invention will be described below with reference to the accompanying drawings. 1 is a front view showing an example of a pressure resistant plastic bottle of the present invention, FIG. 2 is a sectional front view of a bottom portion, FIG. 3 is a bottom view of a leg portion, and FIG. 4 is a bottom view of a leg portion of a conventional pressure resistant plastic bottle. .

The pressure resistant plastic bottle of the present invention is shown in FIG.
As shown in FIGS. 3 to 3, a plurality of legs 2 having a grounding portion 21 at the lowermost end are formed at equal intervals on the peripheral end portion of the bottom portion 12 connected to the body portion 11 and are not connected to the grounding portion 21. In the pressure-resistant plastic bottle 1 having a gently sloping bottom surface 22 facing upward toward the center of the bottle, a concave portion 3 forming a part of a spherical surface is formed adjacent to the bottle center side of the grounding portion 21. It is a pressure resistant plastic bottle 1.

The pressure-resistant plastic bottle of the present invention is used for filling contents such as beer, carbonated drinking water, etc. which generate an internal pressure, and for example, a saturated polyester resin bottle such as polyethylene terephthalate is preferable, and as shown in FIG. A plug portion 13 and a biaxially stretched shoulder portion 14 continuous with the plug portion 13;
Subsequently, the body portion 11 and the bottom portion 12 are provided.

The bottom portion 12 preferably has a basic structure of a pressure-resistant shape that projects downward in a hemispherical shape as shown in FIG. 2, and a plurality of leg portions are provided around the hemispherical bottom portion 12. 2 is bulged. Of course, a pressure resistant shape in which the central portion of the bottom portion 12 is recessed upward may be used.

As shown in FIG. 2, the leg portion 2 bulges out in a substantially right-angled triangular shape in vertical section, and the steeply inclined outer wall 23 and the gently inclined bottom surface 22 form a substantially right angle, and at the same time, it comes into contact with the ground. A basic shape in which side walls 24 are formed on both sides of the portion 21 is preferable.

Further, as shown in FIGS. 2 and 3, it is more preferable that the outer surface wall 23 of the grounding portion reaches the linear grounding portion 21 through the arcuate surface 25 and is continuous with the bottom surface 22.

On the bottom surface 22, a concave portion 3 forming a part of a spherical surface is formed adjacent to the bottle center side of the ground portion 21.

The pressure-resistant plastic bottle 1 of the present invention is filled with carbonated drinking water or the like, and the bottom portion 1 is activated by the action of carbon dioxide gas or the like.
When a large internal pressure is applied to 2, the bottom surface 22 of the leg 2 is
Axial, radial, and circumferential stresses act on, but the reinforcing effect of the concave portion 3 formed adjacent to the bottle center side of the grounding portion 21 and forming a part of the spherical surface having the most excellent pressure resistance. As a result, it is possible to prevent the leg portion 2 from being deformed in the axial direction and the radial direction of the bottle, and it is possible to prevent the grounding point from moving inward and the standing posture of the bottle from becoming unstable.

Moreover, the concave portion 3 forming a part of the spherical surface can prevent the occurrence of crazing, and the reason is as follows.
Since the contour around the concave portion 3 forming a part of the spherical surface is a uniform circular shape, it is considered that there is no geometrical non-uniformity point where the stress concentrates even if a circumferential stress is generated by the internal pressure. .

[0016]

According to the present invention, the peripheral end of the bottom part connected to the body part is
In a pressure-resistant plastic bottle in which a plurality of legs having the lowermost end portion as a grounding portion are formed at equal intervals, and a bottom surface having a gentle slope that is connected to the grounding portion and is upward toward the center of the bottle is formed, Since it is a pressure-resistant plastic bottle characterized in that a concave portion forming a part of a spherical surface is formed adjacent to the bottle center side of the portion, the legs are suppressed from being deformed in the axial direction and the radial direction of the bottle, It is possible to prevent the ground contact point from moving inward and making the standing posture of the bottle unstable, and also to prevent crazing.

[Brief description of drawings]

FIG. 1 is a front view showing an example of a pressure-resistant plastic bottle of the present invention.

FIG. 2 is a sectional front view of the bottom of FIG.

3 is a bottom view of the leg portion of FIG.

FIG. 4 is a bottom view of a leg portion of a conventional pressure-resistant plastic bottle.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Pressure-resistant plastic bottle 11 Body part 12 Bottom part 2 Leg part 21 Grounding part 22 Bottom surface 3 Recess which forms a part of spherical surface

Claims (1)

[Claims] 1. A plurality of legs, whose bottom end is a grounding portion, are formed at equal intervals on a peripheral end portion of a bottom portion connected to the body portion, and the legs are connected to the grounding portion toward the center of the bottle. In a pressure-resistant plastic bottle that has an upwardly sloping bottom surface,
A pressure-resistant plastic bottle, characterized in that a concave portion forming a part of a spherical surface is formed adjacent to the center of the ground portion of the bottle.