JPH06183429A - Pressure resistant freestanding container - Google Patents

Abstract

(57) [Abstract] [Purpose] To provide an integrally molded pressure resistant container that does not use a base cup and has excellent self-sustaining stability even when internal pressure is applied. [Structure] A plurality of leg portions 10 forming a grounding portion 11 are integrally formed in a bottom portion in a circumferential direction, and at least one recess 12 is provided outside the grounding portion 11. It is a pressure resistant self-supporting container 1.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a pressure-resistant plastic container which is integrally formed with a so-called petaloid-shaped bottom portion and can stand on its own without using a base cup. The present invention relates to a pressure-resistant self-supporting container having excellent self-sustaining stability even when it is opened.

[0002]

A biaxially stretched blow molded container made of a saturated polyester resin represented by polyethylene terephthalate has a very excellent transparency and surface gloss, and is beautiful and has a gas barrier. Excellent in water resistance, water impermeability, content resistance, and storage stability. In addition, it has many advantages such as low heat generation during combustion and easy disposal because it does not damage the furnace. Therefore, it is widely used for various drinking water, seasonings, containers for liquor and other foods.

Among such biaxially stretched blow-molded containers (bottles), there is one in which a so-called base cup is attached to the bottom. The base cup is mounted to impart self-supporting properties to the container and, optionally, to reinforce the bottom, which is often used in containers whose contents have a high internal pressure, such as carbonated drinks. This is because, in such a container, the bottom of the container is generally formed in a rounded convex shape in order to improve the internal pressure resistance.

The above-mentioned container with a base cup is excellent in self-sustaining stability and the bottom portion is reinforced, but since the process of manufacturing the base cup in a separate step and attaching it to the container body increases, the productivity is increased. Inferior. In addition, since the base cup is usually molded with a resin different from that of the container body, the container equipped with the base cup is inferior in recyclability.

Therefore, a container having a structure in which various irregularities are formed on the bottom of the container to reinforce the bottom of the container and at the same time, self-supporting property is secured without a base cup, has been developed and put into practical use.

A typical example of such a container is shown in FIG. 5, (a) is a side view of the container, and (b) is
FIG. 5 is a vertical cross-sectional view of the bottom of the container shown in (a). Container 50
The bottom 51 of the container has a plurality of legs 52, each leg 52 being
It is smoothly continuous from the body wall and has a downward convex shape. The plurality of legs 52 are arranged at equal intervals in the circumferential direction on the bottom 51, and have a grounding portion 53 at the lower end, and the grounding portion 53 makes surface contact with the container supporting surface. With such a bottom structure, when a high internal pressure is applied to the container, stress is applied to the corners of the ground portion 53, and uneven deformation easily occurs from there. A container with a non-uniform deformation in the grounding part lacks self-sustaining stability. In addition, in the example shown in FIG. 5, since the number of legs of the container is 5, another leg portion is included in the vertical sectional view of the bottom portion shown in (b).
I can see 52 '.

Therefore, an object of the present invention is to provide an integrally molded pressure resistant container which does not use a base cup and has excellent self-standing stability even when an internal pressure is applied.

[0008]

In order to solve the above-mentioned problems, the inventors of the present invention have earnestly studied on a pressure-resistant self-standing container in which a plurality of legs forming a grounding portion are integrally formed on the bottom and in the circumferential direction. As a result, the present inventor has found that if at least one recess is provided outside the grounding portion in each leg, the legs are not deformed unevenly even when internal pressure is applied to the container, and good self-sustaining is achieved. The inventors have found that a pressure-resistant self-supporting container having stability can be used, and completed the present invention.

That is, in the pressure resistant self-supporting container of the present invention in which a plurality of leg portions forming the grounding portion are integrally formed in the bottom portion in the circumferential direction, at least one recess is provided outside the grounding portion. It is characterized by being.

[0010]

The present invention will be described in detail below. FIG. 1 shows a bottom structure of a pressure resistant self-supporting container 1 according to one embodiment of the present invention, which is a so-called petaloid-shaped bottom. (a)
Is a bottom view and (b) is a sectional view taken along the line AA of (a). Although only the bottom structure of the container 1 is shown in FIG. 1, the shapes of parts other than the bottom, such as the mouth, shoulder, and body of the container 1, are
Depending on the purpose of use of the container, various shapes found in conventional plastic containers may be appropriately set. A feature of the container of the present invention is the recess formed in each leg at the bottom.

Five legs 10 are formed on the bottom of the container 1 at equal intervals in the circumferential direction.
It has a grounding surface portion 11 which is smoothly continuous from the body wall and has a lower end portion in surface contact with the container supporting surface. In the present embodiment, a vertically elongated elliptical recess 12 is formed in the radial direction on the outside of the ground contact surface 11, one for each leg. The term "longitudinal" as used herein means that the container is long in the height direction of the container in a self-supporting state.

Generally, when a petaloid-shaped container is filled with contents such as carbonated beverages, internal pressure is applied to the container, stress is concentrated particularly on the radially outer corners of the ground contact surface, and the lower ends of the legs are swollen. I try to put it out. However, in the pressure resistant self-supporting container of the present invention, since the concave portion 12 is formed outside the grounding surface portion 11, a large resistance force against swelling is exhibited. Therefore, the lower end portion of the leg portion 10 does not swell, and it is possible to prevent uneven deformation of the leg portion 10. When the recess 12 has a vertically elongated elliptical shape as in the present embodiment, it is preferable to form the recess 12 so that the extension line of the elliptical long axis substantially passes through the center of the bottom.

The recess 12 is not limited to a vertically long elliptical shape, but may be a horizontally long elliptical shape. FIG. 2 shows the bottom structure of the pressure resistant self-supporting container 1 in the case where the recess 12 has a horizontally long elliptical shape. (a) is a bottom view, (b) is a BB sectional view of (a). In this case, it is preferable to form the concave portion 12 so that the major axis of the elliptical shape is substantially a tangent to the outer circumference of the bottom portion.

The shape of the recess 12 is not limited to the elliptical shape,
Various shapes such as a circular shape, a triangular shape, and a quadrangular shape can be used.

Although the number of the recesses 12 may be one for each leg 10 as in the above embodiment, a plurality of recesses 12 may be formed depending on the size of the legs and the bulging pressure. Good.
FIG. 3 shows the bottom structure of the pressure-resistant self-supporting container 1 when a plurality of horizontally elongated oval recesses are formed, and FIG. 4 shows the bottom structure of the pressure resistant self-supporting container 1 when a plurality of vertically elongated oval recesses are formed. . When a plurality of recesses 12 are formed in this way, it is preferable to form the recesses 12 side by side in the circumferential direction.

The place where the concave portion 12 is provided is outside the ground contact surface portion 11 in order to make the self-sustaining stability of the container 1 sufficient. However, even if the recess 12 is formed at a position away from the ground plane 11, the effect of preventing deformation cannot be obtained.
It is preferable to form it as close to the ground contact surface portion 11 as possible.
On the other hand, if the concave portion 12 is formed so as to interfere with the ground plane 11, the self-sustaining stability of the container 1 is rather deteriorated.
It is preferable that 12 is formed with a slight distance from the ground plane 11.

Although the container having five legs is formed with the recessed portion with reference to the accompanying drawings, the number of legs is not limited to this, and the container having various numbers of recessed portions is recessed. May be formed. Also, the legs need not be evenly spaced.

Polyester is preferable as the resin forming the container. As the polyester resin, a thermoplastic resin composed of saturated dicarboxylic acid and saturated dihydric alcohol can be used. Saturated dicarboxylic acids include terephthalic acid, isophthalic acid, phthalic acid, naphthalene-1,4-
Or 2,6-dicarboxylic acid, diphenyl ether-4,4′-dicarboxylic acid, diphenyldicarboxylic acids, aromatic dicarboxylic acids such as diphenoxyethanediethanedicarboxylic acid, adipic acid, sebacic acid, azelaic acid, decane-
Aliphatic dicarboxylic acids such as 1,10-dicarboxylic acid and alicyclic dicarboxylic acids such as cyclohexanedicarboxylic acid can be used. As the saturated dihydric alcohol, aliphatic glycols such as ethylene glycol, propylene glycol, trimethylene glycol, tetramethylene glycol, diethylene glycol, polyethylene glycol, polypropylene glycol, polytetramethylene glycol, hexamethylene glycol, dodecamethylene glycol and neopentyl glycol are used. Glycols, cycloaliphatic glycols such as cyclohexanedimethanol, 2,2-bis (4 '
-β-hydroxyethoxyphenyl) propane, other aromatic diols and the like can be used. A preferred polyester is polyethylene terephthalate consisting of terephthalic acid and ethylene glycol.

Polyester resin has an intrinsic viscosity of 0.5 to 1.
5, preferably having a value in the range 0.55 to 0.8. In addition, such polyester is produced by melt polymerization,
Those that have been subjected to reduced pressure treatment or heat treatment in an inert gas atmosphere at a temperature of 250 ° C., or those that have reduced the content of oligomers and acetaldehyde which are low molecular weight polymers by solid-phase polymerization are suitable.

In the polyester resin, additives such as stabilizers, pigments, antioxidants, heat deterioration inhibitors, ultraviolet deterioration inhibitors, antistatic agents, antibacterial agents and the like and other resins can be added in appropriate amounts.

The pressure resistant self-supporting container using the above resin can be easily manufactured by a known biaxial stretch blow molding method using a mold having a shape capable of forming a recess.

Although the present invention has been described above with reference to the accompanying drawings, the present invention is not limited to this, and various modifications can be made without departing from the concept of the present invention. For example, the shape, installation position, arrangement method, etc. of the recesses can be appropriately changed in consideration of the size, shape, application, appearance, etc. of the container.

[0023]

As described in detail above, in the container according to the present invention, at least one recess is provided outside the grounding portion of each leg, so that the legs are uneven when filling the contents. It does not deform and has excellent self-sustaining stability.

The container of the present invention is suitable for containers (bottles) of carbonated drinks and various foods and drinks.

[Brief description of drawings]

FIG. 1 shows a bottom structure of a container according to an embodiment of the present invention, (a) is a bottom view of the container, and (b) is a vertical cross-sectional view of the bottom of the container.

FIG. 2 shows a bottom structure of a container according to another embodiment of the present invention, (a) is a bottom view of the container, and (b) is a vertical cross-sectional view of the bottom part of the container.

FIG. 3 shows a bottom view of a container according to another embodiment of the present invention.

FIG. 4 shows a bottom view of a container according to another embodiment of the present invention.

FIG. 5 shows an example of a conventional plastic container having a petaloid bottom shape, in which (a) is a side view and (b) is a side view.
[Fig. 4] is a vertical cross-sectional view of its bottom.

[Explanation of symbols]

 1,50 Pressure-resistant freestanding container 10,52 Legs 11,53 Grounding surface 12 Recess 51 Bottom

Claims (1)

[Claims] 1. A pressure-resistant self-supporting container in which a plurality of legs forming a grounding portion are integrally formed in a bottom portion in a circumferential direction, and at least one recess is provided outside the grounding portion. A pressure resistant self-supporting container characterized in that