JPH07285527A - Heat resistant and pressure resistant self-standing container - Google Patents

Abstract

PURPOSE:To prevent the protrusion of the bottom part which spoils the self-standing stability at the time of a heat-sterilization of a container from generating, and at the same time, improve the heat resistance and pressure resistance by a method wherein a specified area of the bottom part which is easy to generate a creep deformation due to the increase in an internal pressure at the time of heat-sterilization is crystallized, and at the same time, the internal peripheral diameter of a mouth part is specified to the external peripheral diameter. CONSTITUTION:A lower part 14 of a neck support ring 13 of a preform which is obtained by injection-forming of PET is crystallized by locally heating with an infrared ray heater. In this case, the internal peripheral diameter of the mouth part of the preform is set in a range of 60-90% based on an external peripheral diameter 16. Then, such a preform is biaxially stretch-blow-formed, and a self-standing container of which five leg parts 5 are expanded in the radial directions around a bottom central part 3 with equal intervals is obtained. Then, the bottom part of this container is heated by an infrared ray heater through a shielding plate, and the bottom central part 3, its peripheral parts 4 and areas of trough line parts 6 which are close to the bottom central part are crystallized, and the bottom part is processed so that the bottom part may not protrude at the time of heat-sterilization.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a self-standing container made of biaxially stretched blow-molded saturated polyester, which is suitable for filling carbonated drinks, soft drinks and the like. The present invention relates to a self-supporting container having excellent heat resistance and pressure resistance during heat sterilization.

[0002]

2. Description of the Related Art Conventionally, as a heat-resistant and pressure-resistant container, in order to improve the internal pressure resistance of the container body, the bottom portion is bulged to form a hemispherical shell, and a base cup molded into a bottomed cylinder is attached to this. Then, the mainstream is a container with a self-supporting function. However, the use of the base cup requires that the base cup be separately molded and mounted and fixed, the weight of the container becomes large and the shape also becomes large, and hot water is sufficiently supplied to the bottom of the container during the heat sterilization process. There were various problems such that the heat sterilization of the contents could not be smoothly carried out because it did not reach, and that at this time, water was accumulated in the base cup and it was difficult to drain it quickly.

Further, it is desired to effectively reuse a used empty container from the viewpoint of resource saving and environmental problems.
In a container equipped with a base cup, the container body and base are usually used.
Since the materials of the scup and the adhesive are different, they must be separated when they are reused, and there is a problem that the process cost becomes high.

Due to these problems, a heat-resistant and pressure-resistant container that does not require a base cup has been desired. Several proposals have been made for pressure-resistant containers that do not require a base cup, and generally, a plurality of legs are radially bulged around the center of the bottom, and valleys are formed between these legs. It has either a structure in which a line portion is formed or a champagne type structure, and is disclosed in, for example, Japanese Patent Publication No. 48-5708.
Japanese Patent Publication No. 59-40693, Japanese Patent Publication No. 6-9170
JP-A-63-202424 and JP-A-3-43342.

[0005]

However, although the container described in each of these publications can achieve satisfactory performance as a pressure resistant container, when used as a heat resistant and pressure resistant container for performing a heat sterilization step. Can't get enough performance. That is, in the containers described in the above publications, since the unstretched region or the low-stretched region exists in the center of the bottom and the periphery of the center, the temperature of the contents becomes about 50 ° C to 70 ° C during heat sterilization. When it rises, the internal pressure increases, and the container material itself also easily undergoes creep deformation, so that the center part of the bottom part and the low-stretching region around the center part undergoes creep deformation to project, and the container stands by itself. You will lose stability.

As a method for solving this problem, for example,
It is conceivable to use the container described in JP-A-5-85535. Since this container is a container in which the central portion of the bottom portion is crystallized and the periphery of the central portion is sufficiently stretched, it is possible to suppress the deformation of the bottom portion to some extent when the internal pressure increases during heat sterilization. However, even in the case of this container, it is difficult to sufficiently stretch the valley line portion formed between the leg portions and a low stretched region remains in the portion, so that the portion is not cleared during heat sterilization. -There is a problem in that the bottom portion is projected to lose the self-sustaining stability due to the deformation of the base, or the self-sustaining stability is maintained, but the flavor line is greatly lowered to lose the practicality.

As a result of earnest research by the researchers of the present invention, a bottom structure in which a plurality of legs are radially bulged around the center of the bottom and a valley line portion is formed between the legs. in the case of,
It was found that the stress due to the internal pressure was concentrated especially on the peripheral part of the center of the bottom part and the valley line part.Furthermore, in the bottom protrusion during actual heat sterilization, creep deformation of the part of the valley line part close to the center part was observed. I found it to be particularly large.

The present invention solves such a problem, and is apt to cause creep deformation due to an increase in internal pressure during heat sterilization, mainly near the periphery of the bottom center and the center of the valley line. It is intended to provide a heat-resistant and pressure-resistant self-supporting container which does not lose its self-sustaining stability due to its bottom portion protruding during heat sterilization by crystallizing a part and which is also excellent in chemical resistance.

[0009]

That is, the first aspect of the present invention
The invention, in a biaxially stretched blow molded saturated polyester resin hollow container consisting of a mouth, a shoulder, a body and a bottom, wherein the bottom is a plurality of legs radially expanded around the center of the bottom. It has a self-supporting structure in which a valley line portion is formed between these leg portions and the following (A) to (E)
At least one portion selected from the above is crystallized, and the inner diameter of the mouth / neck portion is 60% of the outer diameter.
% To 90%, the mouth / neck portion has a threaded portion, and at least this threaded portion has a residual internal stress / strain relaxed by heat treatment, and the neck portion that connects the mouth / neck portion and the shoulder portion is not stretched. A heat-resistant and pressure-resistant freestanding container characterized in that a part thereof is crystallized. (A) Center part of bottom part (B) Peripheral part of center part of bottom part (C) Part close to center part of bottom part of valley line part (D) Part of peripheral part of center part of bottom part of leg to ground part (E ) Portion between (C) and (D) In a second aspect of the invention, the body portion is 5 at the time of biaxial stretching blow molding.
The heat-resistant and pressure-resistant freestanding container of the first invention is heat-fixed by being held in a mold heated to 0 ° C to 140 ° C.

The present invention will be described in detail below. The saturated polyester resin used in the hollow container of the present invention is preferably a thermoplastic polyester resin whose main repeating unit is ethylene terephthalate, and the thermoplastic polyester resin is a homopolymer of polyethylene terephthalate as a main component.

As this thermoplastic polyester resin,
Some of the terephthalic acid components are aromatic dicarboxylic acids such as isophthalic acid, naphthalene dicarboxylic acid, diphenyl dicarboxylic acid, diphenoxyethane dicarboxylic acid, diphenyl ether dicarboxylic acid, diphenyl sulfone dicarboxylic acid; hexahydroterephthalic acid, hexahydroisophthalic acid Alicyclic dicarboxylic acids such as; adipic acid, sebacic acid, azelaic acid and other aliphatic dicarboxylic acids; P-
A copolymer obtained by substituting at least one other difunctional carboxylic acid such as oxyacid such as β-hydroxyethoxybenzoic acid and ε-oxycaproic acid can be used.

In the thermoplastic polyester resin, a part of the ethylene glycol component is, for example, trimethylene glycol, tetramethylene glycol, hexamethylene glycol, decamethylene glycol, neopentylene glycol, diethylene glycol, 1,1-cyclohexanedimethylol. , 1,4-cyclohexanedimethylol, 2,2 (4'-β-hydroxyethoxyphenyl)
It may be a copolymer obtained by substituting one or more polyfunctional compounds of other glycols such as sulfonic acid and functional derivatives thereof for copolymerization.

The intrinsic viscosity of the thermoplastic polyester resin used in the container of the present invention is preferably 0.7 to 0.9, and particularly preferably 0.75 to 0.85.

Further, for the thermoplastic polyester resin used in the present invention, additives such as a colorant, a heat deterioration preventing agent, an antioxidant, an ultraviolet absorber, an antistatic agent, an antibacterial agent and a lubricant may be appropriately used. it can.

In the present invention, as a method of partially crystallizing the bottom of the container, a heat source such as an infrared heater, hot air, an infrared lamp, a quartz tube heater, or a high frequency heating device is used. There is a method in which a shield plate having a slit is installed between the two, and a desired portion of the bottom of the container is heated through a slit provided in the shield plate to perform thermal crystallization. It is preferable that the surface shape of one surface of the shielding plate has a concave shape substantially similar to that of the container bottom portion, and the container bottom portion and the shielding plate are fitted to each other. The heat of the heat source reaches the bottom of the container through the slit of the shielding plate, and the heat crystallizes a desired portion of the bottom. In addition, the shielding plate keeps the surface temperature constant at a temperature not higher than the Tg of the container material by passing cooling water or hot water, and prevents the portion in contact with the bottom of the container from being heated to a high temperature exceeding Tg. Is preferred.

In the present invention, (A) to the bottom of the container
The portion (E) is a low stretched portion at the bottom of the container. (A)
The bottom center portion is, for example, a portion indicated by 3 in FIG. 24, (B) the peripheral portion of the bottom center portion is a portion indicated by 4 in FIG. 24, and (C) the bottom center portion of the valley line portion. The part near to is the part near the inner center of the valley line part, which is 5% of the whole valley line part.
.About.85%, particularly preferably 10% to 50%, for example, the portion indicated by 6A in FIG. (D) From the edge of the peripheral part of the bottom center of the leg to the ground contact part,
Of the legs, the part from the edge of the peripheral part of the center of the bottom of the legs to the ground contact part, for example, the part indicated by 7 in FIG. (E) The portion between (C) and (D) is, for example, the portion indicated by 20 in FIG.

In the present invention, at least one portion selected from (A) to (E) is crystallized,
A preferred configuration is a combination including (B) and (C), and a particularly preferred configuration is a combination of (a) to (e) below. By crystallizing the bottom of the container, creep deformation of the bottom of the container during heat sterilization can be suppressed. (B) Combination of (A), (B) and (C) (b) Combination of (A), (B), (C) and (D) (C) (A), (B), (C) , Combination of (D) and (E) (d) combination of (B), (C) and (D) (e) combination of (B), (C), (D) and (E)

The crystallized portion of the bottom of the container of the present invention is
The density of polyethylene terephthalate is 1.350 g / cm ³ to 1.
It is in an opaque state in the range of 390 g / cm ³ , and a particularly preferable density is 1.355 g / cm ^{3 to} 1.385 g / cm ³ . If the density of the crystallized part is less than 1.350 g / cm ³ , the bottom part of the container may creep and deform due to internal pressure during heat sterilization of the container, and the product may lose its self-standing stability and lose its commercial value. . Further, if it exceeds 1.390 g / cm ³ , the impact strength of the crystallized portion is lowered, and the bottom portion may be broken when the container is given a drop impact.

The bottom of the container to be crystallized in the present invention is one of the parts where craze is likely to occur. Cray
Is further promoted by a lubricant or the like in the conveyor line of the filling factory and causes stress cracks, but the chemical resistance of the material can also be improved by crystallizing the part, so the occurrence of stress cracks is suppressed. can do.

The mouth and neck of the container of the present invention has a temperature of 70 ° C to 130 ° C.
After heating to ℃ to relax the residual internal stress and strain of the material, it is gradually cooled so that strain does not re-occur. As a result, a heat-shrinkage of the mouth and neck that occurs during heat sterilization is small, and a self-supporting container having sufficient heat resistance can be obtained. Further, since the screw portion is not whitened and crystallized, it does not cause a rapid shrinkage when relaxing the residual internal stress and strain of the material, and is excellent in dimensional accuracy.

The container neck in the present invention has an inner diameter of 60% to 90% of the outer diameter, and particularly preferably,
74% to 77%. This prevents deformation due to the tightening force of the cap during heat sterilization, and good performance can be obtained. If it is less than 60%, the thickness of the mouth is too thick, which is not preferable in appearance, and there is a problem that the nozzle cannot be smoothly inserted when filling the contents. On the other hand, if it exceeds 90%, the thickness of the mouth portion becomes too thin and the strength decreases, which may cause deformation due to the tightening force of the cap or the like.

In the present invention, the unstretched portion of the neck portion connecting the neck and shoulder portion of the container is crystallized, and the portion is, for example, the hatched portion shown by the lower portion 14 of the neck support ring in FIG. Say By crystallizing the lower part of the neck support ring, it is possible to suppress creep deformation of the portion during heat sterilization. If the portion is not crystallized, the portion undergoes creep deformation during heat sterilization, the overall height and volume of the container are significantly increased, and the container loses practicality.

The body of the saturated polyester resin container of the present invention has a body temperature of 50 ° C. to 140 ° C. during biaxial stretching blow molding.
It is held in a mold that has been heated to and is heat-fixed. By heat-setting, the crystallinity of the material can be increased, and the temperature of the contents during the heat sterilization of the container is 50 ° C to
When the temperature rises to 70 ° C., thermal deformation and creep deformation of the container can be suppressed. The higher the heat setting temperature, the better the heat resistance and pressure resistance of the container, but the longer the time required for the cooling step when the container is taken out of the mold, the longer the overall molding cycle. From the balance, the mold temperature is more preferably 60 ° C to 95 ° C.

[0024]

The present invention will be described in detail below with reference to examples.

EXAMPLE 1 About 6 mm below the neck support ring 13 of a preform 11 (shown in FIG. 19) obtained by injection-molding polyethylene terephthalate (IV = 0.85), a lower part 14 of the neck support ring was fitted with an infrared heater. It was locally heated with a taper to be crystallized, and the screw portion 12 of the mouth and neck was heated at 100 ° C. for 20 minutes and then gradually cooled to relieve residual internal stress and strain. The inner diameter 15 of the mouth and neck of this preform was set to be 76% of the outer diameter 16 (shown in FIG. 20). After reheating the part of the preform except the mouth and neck and the lower part of the neck support ring, it is placed in a blow mold and stretched in the circumferential direction by air blow while stretching in the axial direction by a stretch rod, Biaxial stretch blow molding was performed. At this time, while the body of the mold was heated to 90 ° C., heat fixing was performed for 5 seconds, and then air at room temperature was circulated in the blow mold to cool the molded body and then taken out to obtain a container. Got In this container, as shown in FIGS. 2 and 3, five legs 5 are radially bulged around the bottom central portion 3 at equal intervals, and valley lines 6 are provided between the legs 5. It has a self-supporting bottom structure formed.

Next, this container was placed on a shield plate 8a as shown in FIGS. 4 and 5, and the bottom of the container was heated from below the shield plate 8a by an infrared heater. 3, a self-standing container having a container bottom 2a (shown in FIG. 6) in which the peripheral portion 4 of the bottom center portion and the portion 6A near the bottom center portion of the valley line portion were crystallized were obtained. The crystallized portion at the bottom of the self-supporting container was cut off, and the density was measured by the density gradient tube method. As a result, it was 1.365 g / cm ³ . The total height of this container was 305 mm, the volume of the contained taste line was 1.5 liters, and the inner diameter of the neck of the container was 76% of the outer diameter. FIG. 1 shows a front view of the self-supporting container.

In the above, the surface shape of the shielding plate 8a is substantially the same as the bottom surface of the container, and has the slit 9a as shown in FIGS. The radiant heat of the infrared heater reaches the bottom of the container through this slit, and the desired part can be crystallized by the heat. By passing cooling water or hot water through the shield plate, the surface temperature of the shield plate can be kept constant, and the portion in contact with the bottom of the container can be prevented from reaching a high temperature exceeding the Tg of the material.

Embodiment 2 Similar to Embodiment 1, a shielding plate 8b as shown in FIGS.
The bottom of the container is heated using the
A container bottom 2b was obtained in which the portion 6A near the center of the bottom of the valley line portion was crystallized (shown in FIG. 9). The crystallized portion at the bottom of the self-supporting container was cut off and the density was measured and found to be 1.363 g / cm ³ . The total height of this container is 305m
m, the taste line capacity was 1.5 liters, and the inner diameter of the neck of the container was 75% of the outer diameter.

Example 3 Similar to Example 1, a shielding plate 8c as shown in FIGS. 10 and 11 was used to heat the bottom of the container and to close the center 3 of the bottom and the center of the bottom of the valley portion. A container bottom 2c in which 6A was crystallized was obtained (shown in FIG. 12). The crystallized portion at the bottom of the self-supporting container was cut off, and the density was measured and found to be 1.365 g / cm 3. The total height of this container is 305m
m, the taste line capacity was 1.5 liters, and the inner diameter of the neck of the container was 76% of the outer diameter.

Example 4 In the same manner as in Example 1, a shielding plate 8d as shown in FIGS. 13 and 14 was used to heat the bottom portion of the container, and the bottom center portion 3 and the bottom center peripheral portion 4 were used. And a portion 6A near the bottom center of the valley line portion, a portion 7 from the peripheral edge of the bottom center portion of the leg to the ground contact portion, and a portion near the bottom center portion of the valley line portion and the bottom center of the leg portion. A container bottom 2d was obtained in which the portion 20 between the edge of the peripheral portion and the portion reaching the grounding portion was crystallized (shown in FIG. 15). When the crystallized part of the bottom of the self-supporting container was cut out and the density was measured,
It was 1.366 g / cm ³ . The total height of this container was 305 mm, the volume of the contained taste line was 1.5 liters, and the inner diameter of the neck of the container was 76% of the outer diameter.

Example 5 In the same manner as in Example 1, the shielding plate 8e as shown in FIGS. 16 and 17 was used to heat the bottom of the self-supporting container, and the portion 6A near the center of the bottom of the valley line portion was crystallized. The container bottom 2e thus obtained was obtained (shown in FIG. 18). At this time, the heating time of the bottom is 1.5
Doubled The crystallized portion at the bottom of the self-supporting container was cut off, and the density was measured and found to be 1.375 g / cm ³ . The total height of this container is 305 mm, the volume of the taste line is 1.5 liters, and the inner diameter of the neck of the container is 76 relative to the outer diameter.
%Met.

Comparative Example 1 The same procedure as in Example 1 was carried out except that the heating and thermal crystallization of the bottom of the container were not performed. The bottom of the obtained hollow container was not crystallized at all.

Comparative Example 2 The same procedure as in Example 1 was carried out, except that the screw portion 12 at the mouth and neck of the preform 11 was not heated and gradually cooled, and the internal residual stress and strain were not relaxed.

COMPARATIVE EXAMPLE 3 In Example 1, the neck support ring lower portion 14 of about 6 mm below the neck support ring 13 of the preform 11 is used.
Was performed in the same manner except that was not crystallized.

Evaluation Method and Results (1) Self-Stability Stability: The one in which the central portion of the bottom portion did not project below the grounding surface of the leg portion was marked with ◯, and the one with protruding portion was marked in x. (2) Amount of drop in taste line before and after the evaluation The difference in height from the tip of the mouth and neck of the hollow container to the liquid level of the contents was determined. A fall amount of 20 mm or less is considered good. (3) Amount of Deformation of Inner Diameter of Mouth and Neck Before and after the evaluation, the inner circumference of the mouth and neck with the cap removed was measured to obtain the difference. (4) Total deformation amount Before and after the evaluation, the height of the entire container was measured to obtain the difference.

12 containers were prepared for each of the containers obtained in Examples 1-5 and Comparative Examples 1-3.
Fill the gas volume of carbonated water to the line of 43mm,
After capping, a hot water shower at 70 ° C. was applied for 30 minutes, and then showering was performed with water at 20 ° C. for 10 minutes to perform cooling, and the self-standing container was evaluated. Evaluation results of self-sustaining stability (bottom protrusion) and measurement results of entering taste line drop amount (12
Table 1 shows the average value of the book. Further, the results (average value of 12 bottles) obtained by opening the cap and measuring the deformation amount of the inner circumference of the mouth and neck portion before filling and also the total height deformation amount of the container are shown in Table 1.
Shown in.

[0037]

[Table 1] (Note 1) Measurement cannot be performed due to poor self-standing stability.

From the results of the above test, from the results of Examples 1 to 5 and Comparative Examples 1 to 3, the container of the present invention suppresses the bottom protrusion due to creep deformation during heat sterilization and lowers the taste line. It is understood that it is excellent in preventing self-reliance and maintaining self-sustaining stability. The structure of the bottom of the container in the present invention is not limited to the structure of this embodiment, and can be similarly applied to other structures similar to this embodiment. As an example of a self-supporting container having a shape different from that of the first embodiment, there is a container shown in FIGS. 21, 22 and 23.

[0039]

As described above, the self-supporting container of the present invention suppresses the bottom protrusion during heat sterilization to maintain self-supporting stability, has excellent chemical resistance, and has heat and dimension of the mouth and neck. It is possible to provide a heat-resistant and pressure-resistant self-supporting container that is excellent in accuracy, prevents creep deformation of the neck portion, and has excellent heat resistance and pressure resistance of the body portion. Further, since the container according to the present invention does not require a base cup, hot water at the time of heat sterilization reaches the bottom of the container sufficiently, and heat sterilization of the contents can be smoothly performed. Reuse becomes easy.

[Brief description of drawings]

FIG. 1 is a front view of a self-supporting container of the present invention.

FIG. 2 is a bottom view before crystallization of the bottom of the self-supporting container of the present invention.

FIG. 3 is a cross-sectional view of the bottom of the self-supporting container of the present invention.

FIG. 4 is a plan view of a shielding plate used in Example 1.

5 is a view of the shielding plate used in Example 1 as shown in FIG.
It is an A'sectional view.

FIG. 6 is a bottom view of the self-supporting container of Example 1.

FIG. 7 is a plan view of a shielding plate used in Example 2.

8 is a B of FIG. 7 of the shielding plate used in Example 2. FIG.
It is a B'sectional view.

FIG. 9 is a bottom view of the self-supporting container according to the second embodiment.

FIG. 10 is a plan view of a shielding plate used in Example 3.

11 is a cross-sectional view of the shielding plate used in Example 3 taken along the line CC ′ in FIG.

FIG. 12 is a bottom view of the self-supporting container of Example 3.

13 is a plan view of a shielding plate used in Example 4. FIG.

FIG. 14 is a DD ′ cross-sectional view of the shielding plate used in Example 4 in FIG. 13.

FIG. 15 is a bottom view of the self-supporting container of Example 4.

16 is a plan view of a shield plate used in Example 5. FIG.

FIG. 17 is a sectional view of the shielding plate used in Example 5 taken along the line EE ′ in FIG.

FIG. 18 is a bottom view of the self-supporting container of Example 5.

FIG. 19 is a preform used for manufacturing the self-supporting container of the present invention.
FIG.

FIG. 20 is a preform used for manufacturing the self-supporting container of the present invention.
It is a sectional view of the mouth and neck of the mouse.

FIG. 21 is a front view of free-standing containers having different shapes.

22 is a bottom view before crystallization of the bottom portion of the self-supporting container shown in FIG. 21. FIG.

23 is a cross-sectional view of the bottom of the self-supporting container shown in FIG.

FIG. 24 is a view showing each part of the container bottom of the present invention.

25 is a cross-sectional view of the container bottom shown in FIG. 24.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 Freestanding container 2 Bottom part 2a, 2b, 2c, 2d, 2e Partially crystallized container bottom part 3 (A) Bottom center part 4 (B) Bottom center part peripheral part 5 Leg part 6A (C) Valley line part Near the center of the bottom 6 Valley line 7 (D) Bottom part 8a, 8b, 8c, 8d, 8e from the peripheral edge of the center to the ground 8a, 9b, 9c, 9d, 9e Slit 10 Cooling water or hot water piping 11 Preform 12 Screw part 13 Neck support ring 14 Neck support ring lower part 15 Neck inner diameter 16 Mouth neck outer diameter 17 Mouth neck 18 Shoulder 19 Body 20 (E) Valley line The part between the part near the center of the bottom of the part and the part from the edge of the peripheral part of the leg to the ground contact part

Claims (2)

[Claims] 1. A biaxially stretch blow-molded hollow container made of saturated polyester resin comprising a mouth, a neck, a shoulder, a body and a bottom, wherein the bottom has a plurality of legs radially around a center of the bottom. It has a structure in which it bulges out and forms a valley line portion between these leg portions so that it can stand on its own.
At least one portion selected from (E) is crystallized, and the inner diameter of the mouth / neck portion is 6 with respect to the outer diameter.
0% to 90%, the mouth / neck portion has a threaded portion, and at least this threaded portion is relieved of residual internal stress / strain by heat treatment, and the neck portion connecting the mouth / neck portion and the shoulder portion is A heat-resistant and pressure-resistant freestanding container characterized in that the unstretched portion is crystallized. (A) Center part of bottom part (B) Peripheral part of center part of bottom part (C) Part close to center part of bottom part of valley line part (D) Part of peripheral part of center part of bottom part of leg to ground part (E ) Portion between (C) and (D) 2. The body part is formed by a biaxial stretching blow molding process.
The heat-resistant and pressure-resistant freestanding container according to claim 1, which is heat-fixed by being held in a mold heated to 0 ° C to 140 ° C.