JPH10316124A - Self-standing type plastic bottle - Google Patents

Abstract

PROBLEM TO BE SOLVED: To reduce a crack caused by an environmental stress applied by an internal pressure, a deterioration in self-standing stability caused by an unstable deformation of legs or a crack caused by a dropping shock by a method wherein legs and/or valley parts may have a directional characteristic deviating from an imaginary radiating linear line extending from the center of a bottom surface toward a circumference of it. SOLUTION: A self-standing pressure-proof plastic bottle is made such that a plurality of hollow legs 2 projected in a substantial radial direction from the center 10 of a bottom surface of pressure-proof shape projected in a substantial semi-spherical surface in a downward direction toward a circumferential lower part are formed, an outer, lower end of each of the legs 2 has an earth contact part 21 and a valley part 3 extending from the center 10 of the bottom surface is formed between each of the legs 2. The legs 2 and/or valleys 3 have a directing characteristic which is deviated from an imaginary linear line L extending from the center 10 of the bottom surface toward a circumference of it.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method of filling a content liquid having a high internal pressure, such as a juice-containing gas-containing beverage, having heat resistance and pressure resistance to withstand heat sterilization, and integrally forming legs for self-supporting. Self-supporting pressure-resistant plastic bottle.

[0002]

2. Description of the Related Art In recent years, plastic bottles obtained by stretch blow molding plastics such as polyethylene terephthalate and polyethylene naphthalate are extremely superior in impact resistance and lighter weight than glass, so that they can be filled with various beverages. It has been widely used as a container.

[0003] Utilizing strength enhancement by stretch blow molding, it is also used for beverages that generate internal pressure, such as carbonated beverages and beer. In this case, in order to cope with the internal pressure, the bottom of the main body has a bottom surface of a pressure-resistant shape protruding in a substantially hemispherical shape downward, and hollow legs having a grounding portion are arranged at equal intervals in the outer peripheral direction of the bottom surface. A pressure-resistant plastic bottle, which is self-supporting by integrally forming a plurality of radially-integrated bottles, a so-called one-piece bottle, is also widely used.

[0004] These self-supporting pressure-resistant plastic bottles have a complicated shape in which the center of the bottom surface is not easily stretched and a plurality of hollow legs are formed on a substantially hemispherical bottom surface. In severe environments such as heat, there is a possibility that environmental stress cracks due to internal pressure, independence of independence stability due to indefinite deformation of legs, or cracks due to drop impact may occur. Therefore, focusing on these points,
For example, Japanese Patent Laying-Open No. 4-201838 discloses an invention in which valleys formed between the legs are made deep and shallow valleys alternately arranged in the circumferential direction.

[0005]

However, in the above-mentioned conventional self-standing pressure-resistant plastic bottle, the valleys formed between the legs are formed as deep valleys and shallow valleys alternately arranged in the circumferential direction. Inevitably, there is a problem that the number of the valleys and therefore the number of the legs must be an even number.

The present invention solves such a problem, and is less likely to cause environmental stress cracking due to internal pressure, deterioration of self-standing stability due to irregular deformation of the leg, and cracking due to a drop impact. It is an object of the present invention to provide a self-supporting pressure-resistant plastic bottle free from the restriction that the number of parts must be an even number.

[0007]

According to the present invention, there are provided a plurality of hollow legs protruding substantially radially downward from the center of the bottom surface of a pressure-resistant shape protruding substantially hemispherically downwardly toward the periphery. A self-supporting pressure-resistant plastic bottle having a ground contact portion at an outer lower end of a leg and a trough extending substantially radially from the center of the bottom surface between the legs, wherein the leg and / or the trough Has a direction deviating from a virtual radiation straight line extending from the center of the bottom surface to the periphery.

[0008]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below with reference to the accompanying drawings.

FIG. 1 is a partial front view showing an example of a self-supporting pressure-resistant plastic bottle of the present invention, FIG. 2 is a bottom view of FIG. 1, and FIGS. It is a bottom view showing an example.

According to the present invention, as shown in FIGS. 1 to 4, a plurality of hollow legs 2 projecting substantially radially downward from the center 10 of the pressure-resistant shape projecting downward in a substantially hemispherical shape. A self-supporting pressure-resistant plastic bottle having a ground contact portion 21 at the outer lower end of each leg portion 2 and a valley portion 3 extending substantially radially from the bottom center 10 between the leg portions 2. In the above, the leg 2 and / or the valley 3
A self-supporting pressure-resistant plastic bottle having a direction deviating from an imaginary radiation straight line L extending from the bottom center 10 toward the periphery.

As shown in FIG. 1, for example, the self-standing pressure-resistant plastic bottle of the present invention has a plug portion 11 at the upper end, a shoulder portion 12 extending circumferentially below the plug portion 11, and a shoulder portion 12 below the shoulder portion 12. It comprises a cylindrical body 13 and a bottom 14 below the body.

In the present invention, the bottom portion 14 often has a bottom surface 1 protruding downward in a substantially hemispherical shape. If the bottom surface 1 has a pressure-resistant shape, the curvature may change. The center may be recessed upward.

The bottom surface 1 has a center 10 and is formed with a plurality of hollow legs 2 projecting substantially radially downward from the center 10 of the bottom surface.

The hollow leg portion 2 has a ground contact portion 21 at an outer lower end, and a leg lower surface 22 extending inward and upward from the contact portion 21,
It has a leg outer surface 23 extending outwardly from the ground contact portion 21 at a steep slope and continuing to the trunk portion 12, and a leg side surface 24 extending upward from both sides of the ground contact portion 21 and continuing to the valley bottom 31 of the valley portion 3.

The valley 3 is formed so as to be sandwiched between the two legs 2, and the leg side surface 24 also serves as a side surface of the valley 3,
The valley bottom 31 forms a part of the pressure-resistant bottom surface 1 that protrudes in a substantially hemispherical shape, which is the basic shape of the bottom portion 14, extends almost upward outward from the bottom center 1 and continues to the trunk portion 13. ing. The valley bottom 31 may have a linear shape or a wide planar shape.

In the present invention, the direction of the leg 2 and / or the valley 3 means that the center of the leg lower surface 22, the ground contact portion 21 or the leg outer surface 23 constituting the leg 2 in the case of the leg 2. This is the direction in which a virtual line that passes almost in the radial direction is projected on the horizontal plane,
In the case of the valley portion 3, the direction is such that an imaginary line passing through the center of the valley bottom 31 constituting the valley portion 3 substantially in the radial direction is projected on a horizontal plane.
In any case, the orientation may be such that an imaginary line passing through the center of the horizontal cutting line of the adjacent leg side surface 24 is projected on a horizontal plane.

The virtual radiation straight line L extending from the center 10 of the bottom surface toward the periphery also adopts the direction projected on the horizontal plane.

And the leg 2 and / or the valley 3
Having the direction deviating from the virtual radiation line L extending from the bottom center 10 toward the periphery means that the direction has only to have a portion that does not coincide with the radiation line L. is there.

In the example of FIGS. 1 and 2, the outer skirt of the leg side surface 24 constituting the leg 2 is formed into a shape in which only one side is cut off.
The valley bottom 31 has a shape extending to one side from the middle. That is, as shown in FIG.
When an imaginary line 31D passing through the center of the valley bottom 31 substantially in the radial direction is adopted, the imaginary radiation straight line L extending from the bottom center 10 toward the periphery is in good agreement from the center 10 to the middle. The more you go from the outside, the more you get out.

In this example, since the valley bottom 31 of the pressure-resistant shape is expanded from the middle, the pressure resistance is increased by that amount, and the leg 2 has a shape slightly inclined with respect to the vertical, so that a buffering effect against a drop impact appears. The effect of relieving impact stress on the bottom 14 and preventing deformation and cracking in the vicinity of the leg 2 and the center 10 of the bottom is shown.

In the example of FIG. 3, the leg side surface 24 constituting the leg 2
The skirt portion 31 has a shape in which only one side is shaved, and the valley bottom 31 extends to one side from the middle. That is, when the imaginary line 31D passing through the center of the valley bottom 31 substantially in the radial direction is adopted as the directionality of the valley portion 3, the imaginary radiation line L extending from the center 10 of the bottom surface toward the periphery is often one outside. However, as it approaches the center 10, it deviates from the radiation straight line L and shifts from the center 10.

The effect is that the inward direction of the leg 2 and the valley 3 is shifted from the center 10 of the bottom surface, so that the internal pressure and the stress due to the impact transmitted to the center via the leg lower surface 22 and the valley bottom 31. However, it is hard to concentrate on one point of the center 10 of the bottom surface, so that environmental stress cracking due to internal pressure and cracking due to impact hardly occur.

In the example of FIG. 4, the grounding portion 21 constituting the leg 2
Is formed out of a concentric circle. That is, when the virtual line 21D passing through the center of the ground contact portion 21 in the radial direction is adopted as the directionality of the leg portion 2, the virtual radial line L extending from the center 10 of the bottom surface to the periphery deviates. Things.

In order to form the ground contact portion 21 out of a concentric circle, a virtual line passing substantially radially through the center of the leg lower surface 22 and the leg outer surface 23 is also deviated from the virtual radiation line L. The entire part 2 has a twisted shape.

As an effect, since the leg 2 has a shape twisted with respect to the vertical, a buffering action against a drop impact appears, so that the impact stress on the bottom 14 is relieved, and the leg 2
In addition to preventing deformation and cracking in the vicinity of the bottom center 10 and when the free-standing bottle starts to swing left and right, the contact area of the contact part 21 having a shape deviating from the concentric circle is gradual and the rotation There is also an effect that the vibration changes and the vibration stops quickly.

In order to produce the self-standing pressure-resistant plastic bottle of the present invention, for example, a plastic such as polyethylene terephthalate or polyethylene naphthalate is injection-molded to prepare a test tubular preform, which is formed at a temperature higher than the glass transition temperature and lower than the melting point. And a high-pressure fluid is blown with a blow mold to perform biaxial stretch blow molding.

[0027]

According to the present invention, a plurality of hollow legs are formed which protrude substantially radially downward from the center of the bottom surface of the pressure-resistant shape protruding substantially in the shape of a hemisphere downward, and are formed outside each leg. In a self-standing pressure-resistant plastic bottle having a grounding portion at a lower end and a valley extending substantially radially from the center of the bottom between the legs, the leg and / or the valley may have a center at the bottom. Since it is a self-supporting pressure-resistant plastic bottle characterized by having a direction deviating from a virtual radiation straight line extending toward the surroundings from the direction, the legs and the valleys due to the direction deviating from the virtual radiation straight line The inclination and torsion of the wire exhibit a buffering effect on the stress caused by internal pressure and impact, and may cause environmental stress cracking due to internal pressure, deterioration of self-standing stability due to indefinite deformation of the legs, and cracking due to drop impact. An effect that is less, yet there is no restriction that must be an even number the number of legs.

[Brief description of the drawings]

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

FIG. 2 is a bottom view of FIG. 1;

FIG. 3 is a bottom view showing another example of the self-supporting pressure-resistant plastic bottle of the present invention.

FIG. 4 is a bottom view showing another example of the self-standing pressure-resistant plastic bottle of the present invention.

[Explanation of symbols]

 10 Bottom center 2 Leg 21 Ground contact 3 Valley L Virtual radiation straight line

Claims (1)

[Claims] 1. A plurality of hollow legs protruding substantially radially downward from the center of the bottom surface of a pressure-resistant shape protruding substantially hemispherically downward from the center of the bottom, and grounding at the outer lower end of each leg. A self-supporting pressure-resistant plastic bottle having a valley extending substantially radially from the center of the bottom between the legs, wherein the leg and / or the valley extends from the center of the bottom toward the periphery. A self-supporting pressure-resistant plastic bottle having a direction deviating from an extended virtual radiation straight line.