JPH08207919A - Pressure-proof self-standing bottle - Google Patents

Abstract

PURPOSE: To reduce creep deformation and reduce a drop of a fill point by making a bottom center into a protrusion with a circular horizontal part as a lower end and radially providing triangular-pyramid-shaped legs from the circular horizontal part. CONSTITUTION: A body 8 of a bottle comprises an approximately cylindrical side wall, connected from a shoulder 4 and consists of a lower body part 9B having a plurality of ribs formed consecutively with equal intervals in an axial direction and an upper body part 9A having no ribs. The body has a pinch part 10 with a small diameter within a diameter of the body on the lower body part 9B, while a bottom 11 of the bottle is basically a recessed shape swelling downward, wherein a protruding bottom center 14 is a protrusion with a circular horizontal part 13 as a lower end and at least a part of the protrusion is thicker than remaining bottom parts. In addition, a plurality of approximately triangular-pyramid-shaped legs swelling downward from the recess are radially provided from the circular horizontal part 13. The protruding bottom center 14 slightly protrudes outward in a curve by an internal pressure of the bottle thereby reducing creep deformation.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a biaxially stretched pressure resistant self-supporting bottle made of a saturated polyester resin, which is suitable for filling carbonated drinks, soft drinks and the like. For example, the present invention relates to a pressure resistant self-supporting bottle that has stable self-sustaining property, alleviates creep deformation and a decrease in flavoring line associated therewith, and has a reduced bottle weight.

[0002]

2. Description of the Related Art Conventionally, a pressure resistant self-supporting bottle filled with carbonated drinking water has a mouth neck having an open upper edge, a substantially spherical shoulder, a cylindrical body, and a downward bulge. A plurality of leg portions each having a substantially triangular truncated pyramid shape, which is composed of a concave bottom portion and bulges downward from the concave portion, are radially provided. The structure of the bottom of the bottle is proposed in, for example, Japanese Examined Patent Publication No. 48-5708. FIG. 2 is a vertical cross-sectional view of a conventional bottom structure of a pressure resistant self-supporting bottle, wherein reference numeral 11 is a bottom portion, 15 is a leg portion, and 16 is a center portion of the bottom portion. As shown in FIG. 2, the bottom 11 is generally hemispherical including the bottom central portion 16. In the bottom portion 11 shown in FIG. 2, since the center portion 16 of the bottom portion has a hemispherical shape, the internal pressure is unlikely to be concentrated and acts, but the internal pressure is applied to the body portion 8 accordingly.
There is a drawback in that the body portion 8 is significantly deformed, that is, the volume thereof is increased, and as a result, the deterioration of the penetration line is increased.

Further, recently, a bottle which has a plurality of ribs and pinches on the body and which is closer to the design of a glass bottle and has a shoulder is strongly desired by the end consumer. However, when a bottle of this shape is filled with carbonated drinking water and internal pressure is applied, there is a problem that creep deformation becomes large and the amount of reduction in the taste line becomes large. As a countermeasure for this, it is conceivable to increase the weight of the bottle, but there is a drawback that the cost becomes high.

[0004]

DISCLOSURE OF THE INVENTION The present inventors have endeavored to solve the above-mentioned problems in a biaxially stretched bottle made of a saturated polyester resin, and formed in the shoulder portion at equal intervals. A plurality of ribs extending in the axial direction are installed, the body portion is composed of a substantially cylindrical side wall continuous from the shoulder portion, and a lower portion of the body portion having a plurality of ribs continuously formed at equal intervals in the axial direction. And the upper part of the body without the ribs, and the lower part of the body has a pinch part with a smaller diameter than the diameter of the body, and the bottom part is basically a concave shape that bulges downward. The bottom center is convex with an annular horizontal portion as the lower end, and at least a part of the convex is thicker than the bottom remainder, and the concave is The substantially triangular frustum-shaped leg that bulges downward from the It has been reached in a pressure free-standing bottle which is provided to the individual radial. That is, the present invention is a bottle in which the resin is biaxially stretched and blow-molded so that the resin is oriented in two directions, has excellent tensile strength, prevents the creep deformation of the body and deterioration of the flavor line, and the running stability and resistance An object of the present invention is to provide a pressure resistant self-supporting bottle capable of improving the rocker bottom property and reducing the weight of the bottle.

[0005]

That is, the present invention is a biaxially stretch-molded bottle made of a saturated polyester resin, wherein (a) a mouth-neck portion whose upper end is an open edge portion,
(B) a neck continuous with the mouth and neck, (c) a shoulder continuous with the neck, (d) a trunk continuous with the shoulder, and (e)
A bottom portion that closes the lower opening portion of the body portion, (a) at least the portion other than the mouth and neck portion and the neck portion are biaxially stretched, and (b) the shoulder portion extends from the neck portion, and A plurality of ribs, which are formed of an inwardly-extending circular arc that is connected to the shoulder portion and an outwardly-extending circular arc that is continuous with the arc portion, and that are formed at equal intervals and extend in the axial direction are installed on the shoulder portion. (C) The body portion is composed of a substantially cylindrical side wall continuous from the shoulder portion, and a lower portion of the body portion having a plurality of ribs continuously formed at equal intervals and a body portion without the ribs. The upper part of the body, and the lower part of the body has a pinch part having a smaller diameter than the diameter of the body, and (d) the bottom part is basically a downwardly bulging concave part. The central part is convex with the annular horizontal part as the lower end, and at least the convex part is Part of the wall thickness is thicker than the remaining portion of the bottom, and a plurality of substantially triangular frustum-shaped legs bulging downward from the concave portion are provided radially from the annular horizontal portion. It is a pressure resistant self-supporting bottle characterized by being

The present invention will be described in detail below. The biaxially stretched pressure resistant self-supporting bottle of the present invention shown in FIG.
(A) A mouth / neck portion 2 whose upper end is an open mouth edge portion 1,
(B) a neck portion 3 continuous with the mouth / neck portion 2, (c) a shoulder portion 4 continuous with the neck portion 3, (d) a trunk portion 8 continuous with the shoulder portion 4, and (e) a downward opening of the trunk portion 8 Has a bottom portion 11 that closes the portion, and the shoulder portion 4 extends from the neck portion 3 and extends inwardly to connect with the shoulder portion 4 and has a large radius R1 and an outwardly continuous arc. The shoulder portion 4 is provided with a plurality of ribs 7 extending in the axial direction and formed at equal intervals. The body 8 of the bottle is composed of a substantially cylindrical side wall continuous from the shoulder 4, and has a plurality of ribs continuously formed at equal intervals in the lower body 9B having ribs and a body without the ribs. It is composed of an upper portion 9A, and has a pinch portion 10 having a smaller diameter in the diameter of the body portion on the lower portion 9B of the body portion, and the bottom portion 11 of the bottle is basically a concave shape that bulges downward, The convex bottom center portion 14 has a convex shape with the annular horizontal portion 13 as a lower end portion, and at least a part of the convex portion is thicker than the remaining bottom portion, and the concave portion is formed. A plurality of substantially pyramidal truncated pyramid-shaped leg portions 15 bulging downward from the shaped portion are provided radially from the annular horizontal portion 13.

The thickness of at least a portion of the convex bottom central portion 14 is larger than the thickness of the remaining portion of the bottom portion 11. The shape may be a dome shape as shown in FIG. 1, or the top may be flat.

Next, although there are various shapes and numbers of the leg portions 15 in the bottle of the present invention, the number of leg portions is preferably 5.
That is, FIG. 3 is a bottom view showing the shape of the bottom portion of the bottle of the present invention, showing both inclined side surface portions 17 of the leg portion 15, and the valley line portion 12 is such that the leg portion 15 is in the peripheral portion of the bottom portion 11 and is adjacent to each other. It is in the shape of a strip so that it is separated by.

In the pressure resistant self-supporting bottle of the present invention, the downwardly bulging concave shape which is the basic shape of the bottom structure, that is, the shape of the valley line portion 12 is a perfect arc shape as shown in FIG. However, it may be a combination of straight lines and circular arcs.

In the bottle of the present invention, the convex bottom central portion 14 serves to relieve stress concentration. Figure 4
Is shown as a schematic diagram. That is, FIG. 4 shows XX ′ in FIG.
It is a schematic diagram which shows the state of stress concentration relaxation by the cross-sectional view cut along the line and viewed from the arrow. As shown by the dotted line in FIG.
The center portion 14 of the convex bottom portion is slightly curved and protruded outward by the internal pressure of the bottle to reduce stress concentration in the circumferential direction, that is, creep deformation. Then, the thick portion in the convex bottom central portion 14 is not oriented or has less orientation than the rest of the bottom portion 11.

The ratio of the wall thickness of the convex bottom central portion 14 to the wall thickness of the remaining bottom portion is in the range of 1.2: 1 to 20: 1, preferably in the range of 1.2: 1 to 15: 1. Is. If this ratio is too small, the resistance to internal pressure is insufficient. On the other hand, if the ratio is too large, it is not necessary in practice and the cost becomes high, which is not economical. Moreover, the diameter of the convex bottom central portion 14 is 2 to 35% of the diameter of the entire bottom portion 11.
And preferably 2 to 30%, particularly preferably 3 to 2
It is 0%. If the diameter of the convex bottom central portion 14 is too small or too large, the effect of reinforcing the internal pressure is reduced.
Also, the height of the convex bottom center portion 14 from the annular horizontal portion is
The ratio to the height of the entire bottle is preferably 0.1 to 5%, particularly preferably 0.3 to 5%. Providing this convex bottom center portion 14 allows the shoulder portion 4 and the body portion 8 to be provided.
It promotes the effect of relieving the internal pressure to prevent the deterioration of the penetration line due to creep deformation.

The method for producing a pressure-resistant self-supporting bottle of the present invention comprises heating a preform obtained by injection molding, setting it in a molding die having a shape corresponding to a desired bottle shape, and It is stretched by a stretch rod inserted from the neck of the reform, and blow-molded after colliding with the surface of the bottom of the mold, simultaneously with the collision, or before the collision. This pressure resistant self-supporting bottle is a saturated polyester resin pressure resistant self-supporting bottle having a shoulder portion, a body portion, and a bottom portion that closes a lower opening portion of the body portion shown in FIG. 1, and the bottom portion has the shape described above. Therefore, the preform is
At the time of blow molding, the material at the center of the convex bottom located at the center of the bottom of the bottle is configured so that at least a portion thereof is relatively thicker than the orientation material at the bottom.

[0013]

EXAMPLES The present invention will now be described in more detail with reference to examples, but the present invention is not limited to these examples. Example 1 Using polyethylene terephthalate resin (RT-553C) manufactured by Nippon Unipet Co., Ltd., Husky (HUSKY)
A preform having a weight of 49 g was molded with a company injection molding machine. Next, the preform is heated, the preform is set in a molding die having a shape corresponding to the shape of the bottle, the preform is stretched over the entire length of the molding die, and collided with the bottom surface. Blow molding was carried out to obtain a 1.5 liter bottle (the numerical values in the figure shown in FIG. 5 indicate the dimensions of each part, and the unit is mm). The obtained bottle had a plurality of ribs and a convex bottom center portion.
Each bottle was filled with 4.0 vol of carbonated water up to the taste line and stored at 38 ° C. for 1 day and 7 days for evaluation.
Table 1 shows the evaluation results. The blow molding machine and molding conditions are as follows. ○ Blow molding machine Krupp Corpoplast
p Corpoplast) Model LB-01 ○ Blow molding temperature about 85 ° C ○ Blow molding pressure about 35 bar As can be seen from Table 1, the bottle of Example 1 is filled with carbonated drinking water or the like having a high internal pressure. By providing the convex bottom central portion on the bottom portion 11, the internal pressure to the shoulder portion and the body portion is relieved, and the creep deformation is also relieved, thereby reducing the amount of decrease in the penetration line and the occurrence of rocker bottom. It shows that it can be suppressed.

Comparative Example 1 In the same manner as in Example 1, a bottle having no convex bottom center portion (shown in FIG. 6, the numerical values in the figure indicate the dimensions of each portion, and the unit is mm) was obtained. It was Each of the obtained bottles was filled with 4.0 vol.
It was stored for 1 day and 7 days and evaluated. Table 1 shows the evaluation results.

The evaluation method was as follows. 1) Amount of drop in the taste line The taste line of a pressure resistant self-supporting bottle (5 from the tip of the open mouth edge)
The distance at which the liquid level of the contents fell from 0 mm) was measured.
The unit is mm. 2) Rocker bottom If the center of the convex bottom of the bottom or the center of the bottom does not protrude beyond the ground contact surface of the leg, it is defined as "no occurrence" (good),
The projecting one was defined as "occurred" (defective).

[0016]

[Table 1]

[0017]

As is apparent from the above, the pressure resistant self-supporting bottle of the present invention has a bottom structure having sufficient durability against internal pressure, and further, legs are equidistantly arranged at the peripheral end of the bottom. Stable self-supporting property is maintained due to the formation of multiple bottles, and the convex shape at the center of the bottom part makes it possible to improve the deformation by creep, which is substantially improved compared to conventional pressure-resistant self-supporting bottles. And a biaxially stretched pressure-resistant self-supporting bottle having the characteristic of alleviating the deterioration of the flavor line associated therewith. Furthermore, the present invention is excellent in that the amount of resin material required for the entire bottle can be reduced.

[Brief description of drawings]

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

FIG. 2 is a sectional view of a bottom portion of a conventional pressure resistant self-supporting bottle.

FIG. 3 is a bottom view showing the bottom shape of the bottle of the present invention.

FIG. 4 is a schematic view showing a state of stress concentration relaxation in a cross-sectional view taken along the line XX ′ of FIG. 3 and viewed in the direction of arrows.

FIG. 5 is a detailed view of the pressure resistant self-supporting bottle according to the first embodiment of the present invention.

FIG. 6 is a detailed view of a pressure resistant self-supporting bottle of Comparative Example 1 of the present invention.

[Explanation of symbols]

 1 Open mouth edge part 2 Mouth neck part 3 Neck part 4 Shoulder part 7 Rib 8 Body part 9A Upper part of body 9B Lower part of body part 10 Pinch part 11 Bottom part 12 Valley line part 13 Annular horizontal part 14 Convex bottom center part 15 Legs Part 16 Bottom central part 17 Both inclined side surfaces R1 Radius of circular arc protruding inward R2 Radius of circular arc protruding outward

Claims (1)

[Claims] 1. A biaxially stretched bottle made of a saturated polyester resin, comprising: (a) a mouth neck portion whose upper end is an open mouth edge portion, (b) a neck portion continuous with the mouth neck portion,
(C) a shoulder portion continuous with the neck portion, (d) a body portion continuous with the shoulder portion, and (e) a bottom portion closing a lower opening portion of the body portion, and (a) at least the mouth and neck portion and the The portion other than the neck portion is biaxially stretched, and (b) the shoulder portion extends from the neck portion and extends from the inwardly extending arc that joins with the shoulder portion and the outwardly extending arc that is continuous with the arc portion. A plurality of axially extending ribs formed at equal intervals are provided on the shoulder portion, and (c) the body portion is formed by a substantially cylindrical side wall continuous from the shoulder portion, And a lower part of the body part having a plurality of ribs formed at equal intervals in the axial direction and an upper part of the body part without the ribs, and the lower part of the body part has a pinch having a smaller diameter than the diameter of the body part. And (d) the bottom is basically a concave shape that bulges downward, and the center of the bottom is a ring. It has a convex shape having a horizontal portion as a lower end portion, and at least a part of the convex portion has a wall thickness thicker than the remaining portion of the bottom portion, and is substantially bulged downward from the concave portion. A pressure resistant self-supporting bottle, wherein a plurality of triangular pyramid-shaped legs are provided radially from the annular horizontal portion.