JPH0343342A - Pressure-proof selfstanding bottle - Google Patents

Abstract

PURPOSE:To prevent a creep deformation at the shell and decrease of a charged level of a synthetic resin bottle and further increase a stability on transfer, by providing a triangle-pyramidal base of a ground-contacting bottom with a flat face at the end to be a plurality of radiating form from a circular level part. CONSTITUTION:The structure of a bottom 2 is basically a recessed form swelled downward and the center part thereof has a circular level part 9 at the bottom and the top has a form of a closed circular-protruded shape 3. And further, recessed grooves 6 are a plurality of radiating from the level part 9 and a vacant face formed by narrowed recesses 6 at the both sides thereof is the bottom. The recessed part shows a form swelled downward and the base 4 of the almost triangle-pyramidal form, a ground-contacting face of the bottle of the flat bottom face 8 at the front edge thereof, is a form likely provided with a plurality of radiating shape from the horizontal level 9. The circular protruded part 3 is made so that the thickness of at least a part thereof is thicker than that of the rest of the bottom 2. In this way, deformation due to creep and decrease of the charged line are reduced and hence, excellent stability on the transfer on a charging line conveyor is obtained.

Description

[Detailed Description of the Invention] [Field of Industrial Application] The present invention relates to a pressure-resistant self-supporting bottle made of saturated polyester resin and biaxially stretched, which is suitable for filling carbonated drinks, soft drinks, etc., for example. In addition to giving the bottle a self-sustaining function, it also provides stable running performance, has high internal pressure resistance, and reduces deformation of the body by providing a convex part in the center of the bottom. The present invention relates to a pressure-resistant self-supporting bottle body that promotes effects such as preventing creep deformation of the body and reduction in seasoning level.

[Conventional technology]

There are several problems when using synthetic resin bottles as containers for pressurized liquids such as carbonated drinks. In particular, synthetic resin bottles have a problem in that the interior of the thin, flexible wall, which is a characteristic of the bottle, tends to change due to the internal pressure generated by such pressurized liquid.

Traditionally, this problem has been solved by using a hemispherical bottom to distribute the pressure on the bottle as evenly as possible to prevent deformation. However, such a hemispherical bottom is inherently unstable, and a pace cup is attached to the hemispherical bottom in order to make the bottle self-supporting. However, this method increases the manufacturing cost and also has problems such as various vertical degrees depending on the joint state of the pace cup.

Therefore, attempts have been made to produce a pressure-resistant self-supporting synthetic resin bottle body useful for pressurized liquids that does not require a pace cup to be attached.

Many proposals have been made regarding the design of such bottles; for boat fishing, either a bottom with stabilizing legs bulging out from the center of the bottom, or a champagne-type bottom; (For example, Special Publick
No. 08, No. 59-40693, No. 61-9170,
and Japanese Unexamined Patent Publication No. 63-202424).

[Problem to be solved by the invention]

However, none of these conventional bottle bodies are ultimately satisfactory. That is, these bottles have problems such as deformation (particularly in the body) due to creep of the bottle material (particularly in the body) after being filled with a pressurized liquid such as a carbonated drink, and a drop in flavor level.

That is, in the case of a pressurized bottle, since the internal stress is high, the center part 5 of the bottom part 2 is generally formed into a hemispherical shape as shown in FIG.

That is, FIG. 2 is a vertical cross-sectional view of the bottom structure of a conventional general self-supporting bottle in consideration of the pressure resistance of the bottle, in which reference numeral 1 is the body, 2 is the bottom, 4 is the leg, 5 means the center part.

Since the bottom part 2 shown in FIG. 2 has a hemispherical center part 5, the internal pressure is less likely to concentrate on it, but the internal pressure is applied to the trunk part 1, causing significant deformation of the trunk part 1, i.e. It can be said that this causes an increase in volume, resulting in a large drop in seasoning.

Such bottles are made by blow molding injection molded or extruded preforms. That is, the preform is heated, set in a mold corresponding to the desired shape of the bottle, stretched by a stretch rod inserted through the neck of the preform, and simultaneously or directly blow-molded. The stretch rod stretches the preform the full length of the mold so that the bottom of the preform impinges on the bottom of the mold. At this stage the material in contact with the bottom of the mold is frozen, so when the bottle is blow molded, the material around the center of the bottom 2 remains unoriented (although it may be slightly oriented). ) become relatively weaker. In a bottle body such as that shown in FIG. 2, this region of unoriented material extends well into the leg 4 of the base 2, so that the structure of the base 2 is weakened and the said pressurized liquid After filling, it begins to undergo creep deformation. Furthermore, the transition from the non-oriented material to the oriented material in the bottle bottom 2 is quite abrupt, which creates weak points in terms of strength where the transition occurs, and also reduces the resistance of the bottom 2 to stress cracks, etc. . These problems could clearly be solved by making the bottom 2 thicker, but this would increase the amount of material required and thus also increase the weight of the bottle. Therefore, the advantages that make the one-piece bulk over conventional pace cup bottles are diminished.

In addition, in the conventional one-piece original body, the bottom part 2 with respect to the torso part 1
Because the container is supported at a point or plane by a plurality of legs with a small ground contact diameter, it is extremely unstable and tends to fall over on the conveyor line filling the contents.

The present invention was devised to solve the above-mentioned problems with conventional bottle bodies, and is a biaxial system that prevents creep deformation of the body of synthetic resin bottles and a decrease in the seasoning line, and improves running stability. The purpose of this invention is to provide a pressure-resistant self-supporting bottle body that is stretch-molded.

Furthermore, it is an object of the present invention to exhibit low physical properties such as content resistance, chemical resistance, impact resistance, and penetration resistance, as well as to exhibit sufficient mechanical hardness, and to have low heat generation when incinerated. To provide a pressure-resistant self-supporting bottle body formed by biaxial stretching using a saturated polyester resin that burns with water and does not generate any poisonous gas.

[Means to solve the problem]

To summarize the present invention, the present invention relates to a pressure-resistant self-supporting bottle body, which is a biaxially stretched bottle made of saturated polyester resin, and has a mouth where the upper ☆iAi is an open mouth rim. In a self-supporting bottle body having a neck, a shoulder continuous to the mouth and neck, and a bottom that closes a lower open part of the body having a circular cross section and continuous to the shoulder, at least the part below the mouth and neck is It is biaxially stretched, and the bottom part basically has a concave shape bulging downward, and the center part has an annular convex shape with the lower end being an annular horizontal part, and the annular convex part At least a part of the wall is thicker than the rest of the bottom, and furthermore, it has a shape that bulges downward from the concave part, and the tip thereof becomes a flat bottom surface that touches the ground surface of the bottle body. A plurality of substantially truncated triangular pyramid-shaped legs are provided radially from the annular horizontal portion.

According to the present invention, a molding preform is set in a molding mold having a shape corresponding to the shape of a bottle body, the preform is stretched over the entire length of the molding mold, and the bottom of the preform is placed in the molding mold. The saturation is formed by blow molding after impacting the bottom surface of the mold, or simultaneously with or prior to impacting, and has a circular cross-section body and a bottom portion closing the lower opening of the body. In a polyester resin bottle, the bottom has the shape described above, so that when the preform is blow molded, the material of the annular convex part in the center of the bottom of the bottle is oriented in the same direction as the rest of the bottom. A pressure-resistant self-supporting bottle is provided, which is constructed so that at least a portion thereof is relatively thick compared to the material portion, and is made by blow molding.

Hereinafter, the present invention will be specifically explained based on the accompanying drawings.

FIG. 1 is a longitudinal sectional view of an example of the bottle body of the present invention. In Fig. 1, reference numeral 1 indicates the trunk, 2 the bottom, 3 the annular convex portion, 4 the legs, 6 the valley line, 8 the flat bottom, 9 the horizontal portion, and 11 the mouth and neck. , 12 means the shoulder, a means the height of 9, b means the ground diameter, and C means the trunk diameter.

As shown in FIG. 1, the pressure-resistant self-supporting bottle of the present invention has a mouth Mn11 whose upper end is an open rim, a shoulder 12 continuous to the mouth, a body 1 continuous to the shoulder, and a body 1. It has a bottom part 2 that closes the lower open part, and the material and biaxial stretching are the same as the conventional ones, but the structure of the bottom part 2 is different from the valley line part 6.
The prefecture tree has a concave shape that bulges downward as if it were hollowed out, and the central part has an annular horizontal part 9 as the lower end, and the top is closed in the shape of an annular convex part 3. , valley line part 6
exists in a plurality of radial shapes from the horizontal portion 9, the base is an imaginary surface formed by being sandwiched by the valley line portions 6 on both sides, and the gate-shaped portion bulges downward; ;((The flat bottom surface 8 forms the bottom of the bottle body, and the truncated triangular pyramid-shaped legs 4 also have a shape with multiple openings from 9. There is.

The thickness of at least a part of the annular convex part 3 is larger than the thickness of the remaining part of the bottom part 2, and its shape is such that the top part is flat as shown in FIG. Alternatively, it may be dome-shaped. Furthermore, the size may be different, examples of which are shown in Figures 3-1 to 3.
- It is shown as a longitudinal cross-sectional view in Figure 3. Note that the symbols 1 to 4 have the same meanings as in FIG.

Next, although there are various shapes and numbers of legs 4 in the bottle of the present invention, the number is preferably 3 to 7 from the viewpoint of self-supporting stability of the bottle. Examples are shown in FIGS. 4-1 to 4-5. That is, FIGS. 4-1 to 4-5 are bottom views showing examples of the bottom of the bottle body of the present invention, in which the reference numeral 7 means the inclined side surface of the leg, and the others are the first It is synonymous with figure. The valley line portion 6 has a substantially jute-shaped shape such that the leg portions 4 are spaced apart from each other at the periphery of the bottom portion 2.

Finally, in the bottle body of the present invention, the concave shape that is the basic shape of the bottom structure, that is, the shape of the valley line portion 6, does not have to be a perfect arc shape as shown in FIG. It may be a combination of straight lines and circular arcs, an example of which is shown in FIG. That is, FIG. 5 is a longitudinal cross-sectional view showing an example of the valley line portion of the original body of the present invention, and each reference numeral has the same meaning as in FIG. 1.

As shown in FIG. 5, each valley line section 6 includes a first straight section extending downward and inward from point B to point B, a circular arc section extending from point B to point C, and a first straight section extending downward and inward from point B to point B, and a circular arc section extending from point B to point C. G, a straight portion extending from point G to the point, and a horizontal portion 9. The leg portions 4 each have two different ridgeline portions extending from point A to point E, a straight portion serving as a ground contact surface from point E to point F, that is, a flat bottom surface 8, and a portion extending upward and inward from point F to point G. and a straight line portion that meets the lower end point G of the second straight line of the valley line portion 6. The central annular convex portion 3 is joined to the valley line portion 6 at horizontal portions 9 indicated by G and D from the arc portion.

In the original body of the present invention, the annular convex portion 3 is useful for alleviating stress concentration. The situation is shown schematically in FIG. That is, FIG. 6 is a schematic diagram showing the state of stress concentration and relaxation in a longitudinal section taken along the line x-X in FIG. It is.

As shown by the dotted line in FIG. 6, the annular convex portion 3 curves and protrudes slightly outward due to external pressure, thereby alleviating stress concentration in the circumferential direction, that is, creep deformation.

Then, the thicker portion of the bottom portion 3 is not oriented or has less out-of-orientation compared to the rest of the bottom portion 2 .

The wall thickness ratio of the third part to the remaining part is preferably 1.2:1 to 1.2:1.
20:1, more preferably within the range of 1.2:1 to 15:1. If this ratio is too small, there will be insufficient resistance to internal pressure. On the other hand, it is not necessary for this ratio to be too large in practice, and it is not economical because it increases the cost.

The expansion angle of the side wall of the annular convex portion 3 is preferably 60° or less,
More preferably, the angle is less than 45°, and even more preferably less than 30°. Decreasing this expansion angle increases the resistance of the bottom against internal pressure. Further, the diameter of the annular convex portion 3 is preferably 2 to 35%, more preferably 2 to 30%, and even more preferably 5 to 20% of the diameter of the entire bottom portion 2.

If the diameter of the annular convex portion 3 is too small or too large, the reinforcing effect against internal pressure will be reduced.

Therefore, by providing this annular convex portion 3,
It is also believed that it relieves the internal pressure on the body 1 and promotes the effect of preventing a drop in flavor level due to creep deformation.

Further, the original body according to the present invention has a height a (first height) of the horizontal portion 9.
Reference! ', 1' (), that is, the length a of the perpendicular line from the horizontal portion 9 to the ground plane of the assembly, will alleviate the creep deformation of the original body in the axial direction and improve the formability of the leg portion 4. That is.

The height a of this horizontal portion 9 is preferably 1 to 10%, more preferably 1.2 to 5%, even more preferably 1.5 to 3% of the height of the entire assembly. If this is too small, the original body tends to be deformed in the axial direction due to internal pressure, whereas if it is too large, molding tends to be difficult.

Furthermore, it was confirmed through experiments that the problem of overturning on the filling line conveyor can be reduced by increasing the ground contact diameter b (see FIG. 1) of the original material of the present invention. In addition, as shown in FIG. 1, the grounding diameter in this invention means the diameter of the outside rather than the inside of the flat bottom surface 8 which is a grounding surface, ie, the maximum diameter.

In order to obtain stability during running of the filling line conveyor, the ground contact diameter is preferably 75% or more, more preferably 85% or more, and even more preferably 90% or more. If this is too small, the center of gravity will be high and it will become unstable. However, this grounding diameter is up to the same as the maximum trunk diameter,
It is excellent in terms of moldability and pressure resistance.

[Example] Hereinafter, the present invention will be explained in more detail with reference to Examples.
The present invention is not limited to these examples.

Example 1 Resin used Nippon Unipet polyethylene derephthalate resin (IV = 0.75) Preform Injection molding machine manufactured by IIUsKY 42g preform blow mold 11 bottles (Details are shown in Fig. 7 for the present invention bottle and (shown in the control bottle in Figure 8) Molding conditions Blow molding machine Kurtubu Cohoblast
(Krupp Corpoplast) LB-01 Blow molding temperature: Approximately 85°C Blow molding pressure: Approximately 40 bar (1) Creep test Pour 11 pieces of water into the obtained bottles and add hydrogen carbonate to a carbon dioxide volume of approximately 4.3 vol. ) IJ
Mix aluminum and citric acid and store it in a constant temperature bath at 38℃.
Changes over time up to 8 days later were evaluated by the following dimensional changes. Note that the reference value was determined by using each measured value of the bottle after selling the contents as the reference value for the 0th amount, and calculated values for each change over time.

2-1 Body diameter C (shown in Figure 1) 2-2 Full capacity 2-3 Seasoning line -4a (2) Weight distribution From the Z-Z line shown in Figure 7, calculate the weight of the upper and lower parts and the overall weight. It was measured. The results are shown in Table 1.

(3) Running stability test For the assemblies shown in Figure 7, a test was conducted to determine the correlation between the number of falls and the ground contact diameter using a filling conveyor machine manufactured in-house for three types of assemblies with different ground contact diameters. The conveyor speed was 26 m/min. The results shown in Table 2 represent the total of 5 times each.

The results of (1) above are shown in the graphs in Figures 9, 10, 11, and 12, and their corresponding data are shown in Tables 3 to 6.
The state of the test bottle body is schematically shown in FIGS. 12-1 to 12-3. Further, the results of (2) and (3) are shown in Tables 1 to 6.

Note that FIG. 7 is a detailed view of one embodiment of the assembly of the present invention, and FIG.
The figure is a detailed view of a conventional general control bottle, and Figure 9 is a graph showing the comparison test results in terms of the relationship between changes over time (days, horizontal axis) and barrel diameter c (mm, vertical axis).Table 3 is the corresponding data,
Figure 10 shows changes over time (days, sideways) and changes in full capacity (%).
, vertical axis), Table 4 is the corresponding data, Figure 12-1 is a schematic diagram, and Figure 11 is the graph showing the relationship between changes over time (days, horizontal axis) and seasoning line change rate (%, vertical axis). Table 5 is the corresponding data, Figure 12-2 is a schematic diagram, and Figure 12 is the graph showing the relationship between the horizontal axis (days, horizontal axis) and the height a (mm, vertical axis). Graph shown in relation to axis), Table 6
is the corresponding data, and FIG. 12-3 is its schematic diagram.

Table Table Example 2 Resin used Polyethylene terephthalate resin manufactured by Nippon Unipet (IV = 0.75) Preform Injection molding machine manufactured by Husky Co., Ltd. 42g preform blow mold IF bottle (Details are shown in Fig. 13 for the present invention bottle and (shown in Pair!!G bottle in Figure 8) Molding conditions Blow molding machine Tarzub Cohoblast Co., Ltd. 1, B-01 Blow molding temperature Approximately 85°C Blow molding pressure Approximately /1 obar For these, the same as shown in Example 1 A comparative test was conducted. The results are shown in FIGS. 14 to 17, the corresponding data are shown in Tables 7 to 1O, and Table 11 shows the weight distribution. No. 1317J is a detailed diagram thereof.

In addition, Fig. 14 and Table 7 show the change in the diameter of the trunk diameter C by 111, Fig. 15 and Table 8 show the change in the length of the full capacity claw by 111, Fig. 16 and Table 9 show the change over time in the large taste line, and Fig. 17 and the table shows the change over time in the height a of the horizontal portion.

Table ■ As can be seen from these results, the bottles shown in each practical example are able to reduce the internal pressure to the body by providing an annular convex portion in the center of the bottom 2, even when the internal pressure is high, such as with carbonated drinks. It was possible to alleviate the creep deformation, thereby reducing the decline in the seasoning line by reducing the IF curve δ.

Regarding a, too small pieces were unable to stand on their own due to creep deformation, and too large pieces were extremely difficult to mold. Therefore, it can be said that there is an advantage in limiting a. Furthermore, regarding ground contact diameter, 3.b clearly has superiority in terms of running stability. I was insulted.

[Effects of the Invention] As is clear from the above explanation, the structure of the bottom of the antibody according to the present invention has sufficient durability against internal pressure;
Furthermore, since multiple legs are formed at equal intervals around the circumferential edge of the bottom, stable independence can be maintained, and since the entire bottle body is molded from saturated polyester resin, it can be used with different materials. By eliminating the need for a process to separate the molded pace cup and adhesive, effects such as recyclability can be obtained. Furthermore, by providing an annular convex portion in the center of the bottom and providing a length a of a perpendicular line extending from the horizontal portion of the lower end to the ground surface of the bottle, it is substantially improved compared to the existing one-piece antibody. It was possible to provide a pressure-resistant, self-supporting bottle body formed by biaxial stretching and having the characteristics of alleviating the deformation (particularly in the body) caused by creep and the resulting decrease in the flavor profile, and improving the formability.

Also, by limiting the ground contact diameter, stability is achieved when the filling line conveyor runs. It is also possible to provide a pressure-resistant self-supporting bottle body having properties.

Furthermore, the present invention exhibits many excellent effects such as being able to reduce the amount of resin material required for the entire bottle body.

[Brief explanation of drawings]

Fig. 1 is a vertical sectional view of an example of the bottle body of the present invention, Fig. 2 is a vertical sectional view of the bottom structure of a conventional general free-standing bottle body, and Figs. A vertical cross-sectional view showing an example of the annular convex portion in the bottle of the invention, FIGS. 41 to 4-5 are bottom views showing examples of the bottom of the bottle of the invention, and FIG. A vertical cross-sectional view showing an example of the line part, FIG.
A schematic diagram showing the state of stress concentration and relaxation □ in a longitudinal section taken along the X-ray, Figure 7 is a detailed diagram of one embodiment of the present Hiroshi antibody, and Figure 8 is a conventional general symmetrical bottle. Detailed drawing of the body, No. 9
Figures 10, 11 and 12 are graphs showing the results of comparative tests for the antibodies shown in Figures 7 and 8.
Figures 2-1, 12-2, and 123 are schematic diagrams showing the results of the above comparison test, Figure 13 is a detailed diagram of another embodiment of the bottle body of the present invention, Figures 14, 15, Figures 16 and 17
The figure is a graph showing the results of a comparative test of the antibodies shown in FIGS. 13 and 8. 1: body, 2: bottom, 3: annular convex portion, 4: leg, 5:
Central part, 6: Valley line part, 7: Both inclined side parts of legs, 8: Flat bottom, 9: Horizontal part, 11: Mouth and neck part, 12: Shoulder part

Claims (1)

[Claims] 1. A biaxially stretch-molded bottle made of saturated polyester resin, which includes a neck portion whose upper end is an open rim, a shoulder portion continuous to the neck portion, and a cross section continuous to the shoulder portion. In a self-supporting bottle body having a bottom portion that closes a lower open portion of a circular body, at least a portion below the mouth and neck portion is biaxially stretched, and the bottom portion has a concave shape bulging downward. Basically, the center part has an annular convex shape with the annular horizontal part as the lower end, and at least a part of the annular convex part has a wall thickness larger than the rest of the bottom part, and further,
A plurality of substantially truncated triangular pyramid-shaped legs, which bulge downward from the concave portion and have a flat bottom at the tip and form the ground surface of the bottle body, extend from the annular horizontal portion. A pressure-resistant self-supporting bottle body characterized by its radial arrangement.