JP3513539B2 - Synthetic resin bottle - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention is used for synthetic resin bottles, especially large-sized biaxially stretch blow molded bottles made of polyethylene terephthalate resin, in which reduced pressure is generated inside. It relates to the bottle body.

[0002]

2. Description of the Related Art Large biaxially stretch blow molded synthetic resin bottles have excellent contents resistance, are lightweight and have excellent impact strength, and are easy to mold. Therefore, it is used in large quantities, especially as a container for storing liquid.

As described above, a large synthetic resin bottle has many excellent characteristics as a container, but since the body portion, which is the main part of the container, has a small wall thickness, for example, Under a use condition in which a reduced pressure is generated in the sealed bottle as in the case of heating and filling, there is an inconvenience that the wall of the body part is deformed improperly due to the reduced pressure generated in the bottle.

In order to solve this inconvenience, for example, as disclosed in Japanese Utility Model Laid-Open No. 57-199511, a concave portion having a deformable panel wall as a bottom wall which is likely to be depressed and deformed in a part of a bottle body There is a structure in which the reduced pressure generated in the bottle is absorbed by the constant depression deformation in the deformed panel wall, so that an illegal depression deformation does not occur in the other wall portion of the body.

With this construction, the deformable panel wall can be made sufficiently large to obtain a substantially satisfactory decompression and absorption capacity. However, since the body wall is extremely thin, it is possible to reduce the pressure. There was a complaint that the mechanical strength against a load, that is, the rigidity strength was low, and the rigidity strength of the entire bottle could not be sufficiently increased.

Therefore, as a conventional technique for solving this dissatisfaction, the bottle body 2 shown in FIGS. 5 to 7, that is, the upper end of the body 2 having the shape of a square cylinder with a bottom is provided with the shoulder 3 having the shape of a truncated pyramid. A bottle body 1'in which a mouthpiece 4 is continuously provided is considered.

As shown in FIG. 7, this bottle body 1'has a large number of circumferential grooves 5 formed in the body portion 2 in parallel and at the same shallow depth to enhance the rigidity strength of the entire bottle body. By maintaining the four flat wall portions of the body portion 2, that is, the flat wall portion 6 in the flat state as they are, the entire flat wall portion 6 can be depressed and deformed by the reduced pressure generated in the bottle body 1 ′. In this way, the depression deformation of the entire flat wall portion 6 makes it possible to exert a large decompression absorption capability.

[0008]

However, even though the above-mentioned prior art has a wide flat wall portion which is advantageous for absorbing the reduced pressure in the bottle, the flat wall portion has a machine for forming the flat wall portion. Since a circumferential groove is provided to prevent the flat wall portion from deforming easily, the flat wall portion cannot be depressed and deformed sufficiently and easily due to the reduced pressure absorption due to the reinforcing effect of the circumferential groove. Therefore, there is a problem that the reduced pressure absorption ability to be exerted is never sufficient.

Particularly, in the case of a large bottle of 2 liter class, when the content liquid is heated to a high temperature of about 80 ° C. and filled, the degree of decompression generated in the bottle is high.
There is a problem in that the high degree of decompression cannot be absorbed by the depression deformation of the flat wall portion, and the bending depression permanent deformation due to the pressure reduction occurs in a part of the body.

Therefore, the present invention was devised in order to solve the above-mentioned problems in the prior art. In order to increase the rigidity of the entire bottle, a large-sized circumferential groove is provided in parallel with the body. In a synthetic resin bottle body, it is a technical subject to enhance the reduced pressure absorption capacity, and an object thereof is to provide a bottle body having a high reduced pressure absorption capacity while maintaining a high rigidity of the entire bottle body.

[0011]

Means for Solving the Problems The means of the present invention for solving the above technical problems is a large-sized synthetic resin bottle body that is biaxially stretch-blow molded, and has at least a bottomed cylindrical body portion. While providing a pair of parallel flat walls,
A plurality of circumferential grooves are provided in parallel, a flat wall portion is provided with a depression wall portion having a substantially flat shape for decompression absorption, and the circumferential groove of the depression wall portion is made shallow. It is in.

It is preferable that the body has a bottomed rectangular tubular shape, and the wall portion corresponding to the long side surface portion of the body has a flat wall portion, and the body has a bottomed square tubular shape. It is preferable to use the four flat wall portions as the flat wall portions.

[0013]

[Function] Since a plurality of peripheral grooves functioning as reinforcing peripheral grooves are provided in parallel in the body portion of the bottle body, the entire bottle body, particularly the body portion is Demonstrates the same high rigidity and strength as a bottle with a normal reinforcing circumferential groove.

The circumferential groove for increasing the rigidity of the body is
It is also located on the flat wall portion of the body, but the circumferential groove of the depressed wall portion formed by depression in this flat wall portion has a structure with a shallow depth, so this circumferential groove is The function exerted on the recessed wall portion, that is, the function of increasing the self-shape retention ability of the recessed wall portion against an external force acting in the radial direction is weaker than that of the other body portion.

Therefore, when decompression occurs inside the bottle and a force for pushing the wall of the body inward acts, the depressed wall portion, which has a weak reinforcing function by the circumferential groove, is relatively easily acted by this decompression. It begins to collapse and deform, and exerts a reduced pressure absorption function.

The depression deformation of the depressed wall portion for absorbing the reduced pressure is such that the entire depressed wall portion is curved inward in an arc shape and is depressed and deformed. However, the depressed wall portion is originally depressed due to the reduced pressure. Since the flat wall portion is easily deformed, the entire flat wall portion is also curved and deformed with a large radius of curvature as the recessed deformation of the recessed wall portion progresses.

As described above, since the depressed wall portion is depressed and absorbs the reduced pressure, and the flat wall portion is also entirely curved and deformed in the depressed direction with a large radius of curvature, the reduced pressure absorption amount to be exerted is extremely large. And exhibits sufficient decompression absorption capacity.

Further, since the recessed wall portion is provided with the circumferential groove which is continuous from the other body portion although the depth is shallow, the reinforcing function of the circumferential groove with respect to the entire body portion is deteriorated. And the high rigidity strength of the bottle is maintained.

[0019]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to FIGS. The illustrated embodiment shows a large-sized biaxially stretch blow molded bottle body made of polyethylene terephthalate resin. The bottle body 1 has a rectangular pyramid-shaped shoulder portion on the upper end of a body portion 2 having a rectangular tubular shape with a bottom. A short cylinder-shaped mouth 4 having a thread formed on the outer peripheral surface thereof is provided upright through the opening 3.

The body portion 2 is divided into an upper portion and a lower portion by a central circumferential groove that is provided around the center in the height direction, and a lateral groove for reinforcement is provided on the upper portion of the body portion 2 at each side width. It is intermittently formed with a length corresponding to the length, and six circumferential grooves 5 are provided in parallel in the lower portion of the body portion 2, and four flat plate-shaped members constituting the lower portion of the body portion 2 are formed. Among the wall portions, the wall portion corresponding to the long side constitutes the flat wall portion 6.

In the portion from the upper end of the central portion of the flat wall portion 6 to the lower portion thereof, the depth of the circumferential groove 5 is shallow,
A recessed wall portion 7 having a substantially vertically long rectangular shape is recessed. Since the circumferential groove 5 located there is shallow, the recessed wall portion 7 is less likely to be curved and deformed due to pressure reduction than other flat wall portions 6. It is easy to do.

Specific numerical values for the depth of depression of the depressed wall portion 7 and the depth of the circumferential groove 5 in the depressed wall portion 7 are the size of the bottle body 1, the type of liquid to be stored, and the filling liquid content. It is set according to the usage conditions such as the degree of heating, but the height of the body 2 is 240 mm under the condition that the content liquid such as mineral water, oolong tea, and juice is filled at a high temperature of about 80 to 85 degrees. In the case of a 2 liter bottle with a long side width of 105 mm and a short side width of 87 mm, the depression depth of the depression wall portion 7 is about 1.5 mm, and the depth of the circumferential groove 5 in the flat wall portion 6 is 2 mm. Depth of the circumferential groove 5 in the depressed wall portion 7 is 1 mm
It is appropriate to set the degree.

As is apparent from the above-described dimensional structure, the recessed wall portion 7 makes the depth of the circumferential groove 5 shallow, and
It is formed in a depressed form (see FIG. 3) including the above.

FIG. 4 shows the measurement of the vacuum creep characteristics of the bottle 1 of the embodiment of the present invention shown in FIGS. 1 to 3 and the bottle 1'of the conventional example shown in FIGS. The results are shown in FIG. 4, where the characteristic curve a is the characteristic of the bottle 1 of the present invention, and the characteristic curve b is the characteristic of the conventional bottle 1 ′.

As is clear from the measurement results, the bottle 1 of the present invention has a maximum vacuum absorption capacity of 87 ml,
Compared with the conventional bottle body 1'maximum vacuum absorption capacity value of 67 ml,
It exerted a much larger vacuum absorption capacity.

The flat wall portion 6 in which the recessed wall portion 7 is provided is not limited to the long side wall portion of the rectangular tubular body, and for example, each flat wall portion of the rectangular tubular body may be a flat wall. Alternatively, each of the four flat wall portions of the body portion 2 having a square tubular shape with a bottom may be replaced by the flat wall portion 6.
Also good.

Further, in the case of the illustrated embodiment, by providing a large number of circumferential grooves 5, the rigidity of the entire body portion 2 can be increased as compared with the conventional decompression absorption type bottle body provided with the deformed panel wall. Since it is possible to reduce the wall thickness of the body portion 2 by that amount, the amount of material required to mold one bottle is the same as that of the conventional deformed panel in the case of the 2 liter bottle having the above-mentioned size. When the wall was provided, the weight was about 70 to 80 g, whereas in the case of molding one bottle of the same standard, in the case of the present invention, it was possible to significantly reduce it to about 60 to 65 g It was possible to obtain a high economic effect.

Further, in the illustrated embodiment, the shoulder 3 is provided with a vertically long recessed portion 8. The recessed portion 8 is deformed and deformed illegally due to the reduced pressure generated in the bottle body 1. This is to prevent this.

[0029]

Since the present invention has the above-mentioned structure, it has the following effects. Since the recessed wall portion is provided by shallowing the depth of the circumferential groove in the center of the flat wall portion, the recessed deformation of the center of the flat wall portion for absorbing the reduced pressure is likely to occur, and the recessed deformation is easy, and The depression deformation of the depressed wall portion triggers the entire flat wall portion to be curved and deformed with a large curvature to absorb the reduced pressure. Therefore, the entire flat wall portion can obtain a large reduced pressure absorption amount with a small depression amount. As a result, it is possible to exert a large reduced pressure absorption capability without impairing the appearance of the entire bottle.

The flat wall, which is the main part of the reduced pressure absorption,
Since multiple peripheral grooves are provided, it is possible to obtain structurally high rigidity and strength, so that even if it is depressed and deformed due to reduced pressure absorption, it exerts sufficient rigidity as a container and is stable. And can exert good functions.

[Brief description of drawings]

FIG. 1 is an overall front view showing an embodiment of the present invention.

FIG. 2 is an overall side view of the bottle shown in FIG.

FIG. 3 is a plan sectional view taken along the line AA in FIG.

FIG. 4 is a characteristic measurement result diagram showing the reduced pressure absorption characteristics of the bottle of the present invention and the bottle of the related art.

FIG. 5 is an overall front view showing a conventional example.

6 is an overall side view of the embodiment shown in FIG.

FIG. 7 is a plan sectional view taken along the line BB in FIG.

[Explanation of symbols]

1; Bottle 1 '; Bottle 2; torso 3; Shoulder 4; Mouth 5; Circumferential groove 6; Flat wall 7; Cave wall 8; Recess a: Characteristic curve of the present invention b; Conventional example characteristic curve

Front page continuation (56) Reference JP 62-52034 (JP, A) JP 1-88806 (JP, A) (58) Fields investigated (Int.Cl. ⁷ , DB name) B65D 1 / 02 B65D 1/18 B65D 1/44

Claims (3)

(57) [Claims] 1. A body (2) having a bottomed tubular shape is provided with at least a pair of parallel flat walls (6), and
A plurality of circumferential grooves (5) are provided in parallel, and the flat wall portion (6) is provided with a recessed wall portion (7) having a substantially flat shape for decompression absorption. A biaxially stretch blow-molded synthetic resin bottle body in which the groove (5) has a shallow depth and is depressed. 2. The body (2) has a bottomed rectangular tubular shape, and a wall portion corresponding to a long side surface portion of the body (2) is a flat wall portion (6).
The synthetic resin bottle body according to claim 1. 3. The synthetic resin bottle according to claim 1, wherein the body portion (2) has a bottomed square tubular shape, and four flat plate-shaped wall portions of the body portion (2) are flat wall portions (6). body.