JPH07242222A - Pressure-resistant and heat-resistant bottle - Google Patents

Abstract

PURPOSE:To obtain a pressure-resistant and heat-resistant bottle of which the heat-resistant characteristic of the shoulder and the bottom is improved. CONSTITUTION:A plurality of legs 60 are provided at the bottom to make a self-standing bottle structure. A support ring 20 is provided at the neck 10 and the shoulder 30 including an increased diameter part 34 enlarged to the outer diameter of the body 40 is formed under the neck 10. The part 34 of the increased diameter is made within 4.5mm in the distance from the lower face of the support ring 20. It is more preferable to increase the diameter from the position within 3mm. In this way, the length of horizontally non-stretched part 32 is shortened and the stretching magnification of the horizontal axis of the part of widened diameter is increased and the oriented crystallinity is enhanced. And hence, the heat-resistance at the shoulder 30 is improved. The shoulder 30 is stretched to get thin and the economized resin is distributed to the bottom 50. The bottom 50 is thickened for reinforcement and the heat resistance at the bottom is also increased. When polyarylate resin is dry-blended with PET as a resin raw material, the heat resistance is further improved.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a packaging container for, for example, carbonated beverages containing fruit juice, which is made of a synthetic resin and which is required to have internal pressure due to carbonic acid, etc. -Regarding heat resistant bottles.

[0002]

2. Description of the Related Art Generally, a bottle made of a synthetic resin called a biaxially stretched blow molded bottle has a bottomed parison having a neck portion obtained by, for example, injection molding and is positioned in a blow mold cavity. It is formed by stretching in the vertical axis in the direction, stretching in the horizontal axis by the pressure of the gas blown inside, and stretching in the biaxial direction. The bottle thus obtained has a shoulder portion, a body portion and a bottom portion which are continuously formed below the neck portion.

By the way, when the content to be filled is, for example, a carbonated beverage containing fruit juice, the internal pressure acts on the bottle due to carbonic acid and the bottle is heated for sterilization. A synthetic resin bottle provided is used. In order to secure the internal pressure resistance, it is best to set the bottom structure to a downward convex hemispherical shape. The bottom of the bottle is formed in a hemispherical shape so that the inner pressure of the filled contents, for example, vaporized gas from a filler such as carbonic acid, acts uniformly on the inner surface of the bottom.

The bottom structure has a downwardly convex hemispherical shape, and in order to provide a self-supporting bottle, it is necessary to separately form the base cups that serve as the legs and attach the bottom cup to the two-piece type. there were.

In addition, there is known a one-piece type self-supporting bottle in which the bottom of the bottle is provided with a self-supporting shape without using a base cup. In this type of self-supporting bottle, a plurality of legs forming a bottle grounding portion are radially formed at equal intervals in the circumferential direction of the hemispherical bottom, and the legs are integrally formed with the bottle body. . In addition, it has an upward convex hemispherical portion, and a thread tail-like grounding portion is formed around it.
The so-called champagne bottom type also functions as a self-supporting bottle and is known as a bottle having excellent internal pressure resistance.

In recent years, there has been a demand for a large-sized bottle having a volume of 1 liter or more, and as the large-sized pressure-resistant and heat-resistant bottle, only a two-piece type bottle has been put into practical use.

[0007]

However, in the case of a two-piece type bottle, the number of parts is increased by the amount of the base cup, and the number of steps for mounting the base cup is also increased.
There is a drawback that the bottle cost becomes high. Further, the base cup is usually made of a material different from that of the bottle body in order to support the bottle body or to be colored in a decorative sense. Recently, the recycling of used bottles has been popular, but when parts made of different materials are used, it becomes necessary to sort the parts when recycling the bottles.

From this point, one-piece type bottles are noted, but in the champagne bottom type, the volume is 1 in addition to the internal pressure.
Since the self-weight of the contents of liters or more is applied, the upward convex hemispherical portion is easily deformed downward, and the self-supporting property cannot be maintained.

On the other hand, in a self-supporting one-piece bottle having a plurality of legs, even if the center of the bottom portion surrounded by the plurality of legs is projected and deformed downward due to the internal pressure and the own weight of the contents,
An internal pressure resistant bottle that does not impair the self-supporting property can be realized by forming the legs so as not to project below the ground contact surface.

However, the self-standing bottle having a plurality of legs has a relatively complicated bottom shape, and is inferior to the other two types in terms of heat resistance of the bottom.

Therefore, in order to realize a pressure / heat resistant bottle having a relatively large capacity, it is an object to improve the pressure / heat resistance of the bottom portion of a self-standing bottle having a plurality of legs.

The present inventors have attempted to improve the heat resistance of the bottom of a self-standing bottle having a plurality of legs by improving the thickness of the bottom. Here, in this type of blow molding technique, a preform also called a parison is biaxially stretch blow-molded to obtain a bottle. At this time, the weight of the bottle itself has specifications of each company, and it is necessary to set the wall thickness of each portion of the bottle including the bottom portion under the limitation of the limited bottle weight.

As a result of various experiments conducted by the inventors of the present invention, there is a correlation between the thickness of the shoulder portion where the stretching is finished in the initial stage of the blow molding process and the thickness of the bottom portion where the stretching is finished in the final stage. Therefore, it has been revealed that the heat resistance of the bottom portion can be ensured by increasing the thickness by stretching the shoulder portion more than before and ensuring the heat resistance of the shoulder portion. That is, if the shoulder portion is sufficiently stretched to be thin, the bottom portion can be made thicker accordingly.

Therefore, it is an object of the present invention to secure pressure resistance even with a relatively large capacity as a bottom structure having a plurality of legs, and to improve the shape of the shoulder portion so that the shoulder portion Pressure resistance that can ensure the heat resistance of
To provide a heat resistant bottle.

Another object of the present invention is to provide a pressure-resistant and heat-resistant bottle which can ensure heat resistance at the bottom.

Still another object of the present invention is to provide a pressure-resistant and heat-resistant bottle which has improved heat resistance of the shoulder portion and the bottom portion and has good molding stability.

[0017]

According to a first aspect of the present invention, a flange portion is formed so as to project and a neck portion is formed continuously with the neck portion. A shoulder portion having a portion increasing in diameter from the outer diameter of the body, a body portion formed continuously with the shoulder portion, and formed to close the lower end of the body portion,
A bottom portion having at least three or more self-standing legs, and a shoulder portion other than the neck portion, a body portion, and a bottom portion made of synthetic resin obtained by blow molding. Has a shape in which the diameter increase starts from a position where the distance from the lower surface of the flange portion is within 4.5 mm.

According to the invention of claim 1, the length of the unstretched region in the horizontal axis direction from the lower surface of the flange portion to the diameter increasing start position can be set as short as within 4.5 mm, and the diameter increasing start position is The closer to the flange side, the higher the horizontal axis draw ratio in each part of the increased diameter portion of the shoulder portion, and the higher the orientation crystallization. Therefore, the heat resistance in the shoulder portion was improved, which was confirmed by experiments. Therefore, according to the invention of claim 1, even in the case of a large-sized bottle having a volume of 1 liter or more, pressure resistance can be ensured by using the self-standing bottle having a plurality of legs, and the shoulder portion can be secured. We were able to solve the problem of improving the heat resistance at room temperature.

The invention of claim 2 is characterized in that the shoulder portion of claim 1 has a shape in which the diameter increase starts from a position within a distance of 3.0 mm from the lower surface of the flange portion. In this case, the length of the non-stretched portion on the horizontal axis can be further shortened as compared with the first aspect, and the horizontal stretch ratio at each portion in the increased diameter portion of the shoulder portion is increased. The property is improved. This was also confirmed by experiments.

The invention of claim 3 is characterized in that the thickness of the shoulder part of claim 2 is approximately 1.0 to 2.0 mm at a position at a distance of 5 mm from the lower surface of the flange part.

By setting the wall thickness to about 2.0 mm or less, thermal deformation at the shoulder portion can be suppressed to a sufficiently small level for practical use, and by setting the wall thickness to about 1.0 mm or more, molding stability can be obtained. It was confirmed by experiment that the property can be secured.

According to a fourth aspect of the present invention, in the second or third aspect, the bottom portion has a heel portion whose diameter decreases from the outer diameter of the body portion toward the ground contact surface of the leg portion. The ratio of the weight of the bottom to the total weight of the bottle is 20
˜40% by weight.

There is a correlation between the wall thicknesses of the shoulder portion and the bottom portion of the bottle obtained by biaxially stretch-blow molding a constant weight of the preform, and the shoulder portion is thinned as in claim 2 or 3. By doing so, the saved resin can be contributed to the thickening of the bottom portion, and thereby the thermal deformation at the bottom portion can be reduced.

If the bottom is less than 20% by weight of the whole bottle, the thermal deformation at the bottom cannot be reduced to a practically sufficient degree, and if it exceeds 40% by weight, the thickness of the shoulder portion is reduced. Molding becomes unstable because it becomes too thin. It has been confirmed by experiments that by setting the bottom portion within the above range of the weight ratio, the amount of thermal deformation can be kept within a practically allowable range and molding stability can be secured.

A fifth aspect of the present invention is the method according to any one of the first to fourth aspects, wherein the synthetic resin has a glass transition temperature of 185 to 185.
It is characterized by comprising 3 to 10% by weight of a polyarylate resin at 195 ° C. and 97 to 90% by weight of a polyethylene terephthalate resin.

As the weight% of the polyarylate resin mixed with PET increases, the heat resistance of the bottle improves, but 3
If it is less than 10% by weight, there is no noticeable difference from the case of polyethylene terephthalate resin (hereinafter referred to as PET) alone. If it exceeds 10% by weight, the softening point of PET and the polyarylate resin are different, and the drying speed is also different. Due to this, it becomes difficult to maintain molding stability.

[0027]

Embodiments to which the present invention is applied will be described below in detail with reference to the drawings.

Regarding the overall shape of the bottle, FIG. 1 is a front view showing an example of a pressure-resistant and heat-resistant bottle to which the present invention is applied.

The pressure-resistant and heat-resistant bottle is formed by subjecting an injection-molded or extrusion-molded preform to biaxial stretch blow molding in a blow cavity mold.

As shown in FIG. 1, pressure-resistant and heat-resistant bottles are roughly classified into, for example, an injection-molded neck portion 10 on the open end side, and a blow-molded bottle body portion 70 below the neck portion 10. Have and.

The structure of the neck portion 10 is the same as that of a general synthetic resin bottle, and as shown in FIG. 1, for example, a screw portion 12 to which a screw cap is attached, a locking ring 14 therebelow, and further, the same. It has a flange portion, for example, a support ring 20, on the lower side. The support ring 20, which is the flange portion, is an indispensable structure for supporting the bottle when filling the contents in the bottle. On the other hand, the screw portion 12 and the locking ring 14 can adopt various shapes depending on the sealing method of the opening.

The bottle body 70 has a support ring 20.
Shoulder portion 30, body portion 40 and bottom portion 50 in order from the side
Is configured. The shoulder portion 30 has a cylindrical portion 32 of substantially the same size as the outer diameter of the body of the preform before blow molding (in the present embodiment, substantially the same diameter as the outer diameter of the neck portion 10 above the support ring 20). Have. This cylindrical part 3
2, a diameter increasing portion 34 that increases in diameter downward from the outer diameter of the cylindrical portion 32 to reach the outer diameter of the body portion 40.
Have. The diameter-increased portion 34 is usually defined by using a plurality of types of radii of curvature in order to form a smooth curved contour.

The body portion 40 is an area other than the shoulder portion 30 and the bottom portion 50 of the bottle body portion 70, and is set in various shapes in consideration of aesthetics, a labeling area, and the like. In the bottle body 40 of the embodiment, the diameter gradually increases from the lower end of the shoulder portion 30 to reach the uppermost bulge 42 that is most bulged in the radial direction, and the diameter is slightly smaller than the upper ridge 42 in the lower longitudinal region. Becomes a cylindrical portion 44 having substantially the same outer diameter,
Below the cylindrical portion 44, there is a lower top portion 46 having substantially the same diameter as the upper top portion 42.

The bottom portion 50 includes a bottle main body portion 70 including a portion called a heel portion 52 that has a diameter smaller than the outer diameter of the body portion 40.
To form the lower end region of the. The bottom portion 50 has a plurality of legs 60 for functioning as a self-supporting bottle, and has a bottom portion structure shown in FIGS. 2 and 3, for example.

The bottom portion 50 has a downwardly convex spherical portion 54 curved at a constant radius, and further the spherical portion 5 thereof.
For example, five leg portions 60 extending obliquely downward from 4 are provided at substantially equal center angles with respect to the center 56. The leg portion 60 has a change point 62 that is separated from the center 56 by a predetermined distance.
The inclined portion 64 is connected to the spherical portion 54 at and extends obliquely downward from the change point 62 toward the outer side in the radial direction. Then, the lowest point of this inclined portion 64 is configured as a grounding portion 66. A valley portion 68 is formed as a part of the spherical portion 54 between the adjacent leg portions 60, 60.

Embodiment 1 The shape of the shoulder portion 30 having excellent heat resistance in the pressure-resistant and heat-resistant bottle according to this embodiment having the above-mentioned structure will be described. In the first embodiment, the contour of the increased diameter portion 34 in the upper region of the shoulder portion 30 which is enlarged and shown in FIG. 1 has a radius of curvature R and the support ring 20 extending to the center position thereof.
It is set by the distance X from the lower surface.

FIG. 4 is a drawing in which the contour of the upper region of the shoulder portion 30 is drawn by shifting the center of the same radius of curvature R (for example, R = 10 mm) at three positions. The shape line A in FIG. 4 is the distance X1 from the lower surface of the support ring 20 =
This is drawn by setting the center of the radius R at the position of 2.87 mm. Similarly, the shape lines B and C have distances X2 = 3.5 mm and X3 = 4.5 from the lower surface of the support ring 20.
It is drawn by setting the center of the radius R at the position of mm. In either case, the circular arc drawn with the radius R shows the case where it is in contact with the contour of the cylindrical portion 32.

Examination of these three types of shape lines A to C shows that the following is reflected in the bottle characteristics.

(1) When the shape line A is adopted, the length of the horizontal axis unstretched portion in the shoulder portion 30 can be minimized and heat resistance can be improved.

The length of the unextended portion on the horizontal axis of the shoulder portion 30 corresponds to the distances X1, X2, and X3 in each of the three types of shape lines A, B, and C, respectively. In the case of the shape line A, the diameter increase starts from the position of the distance X1 from the lower surface of the support ring 20. In other words, when the shape line A is adopted, the outer diameter is the same as the outer diameter of the preform 100 shown in FIG. 4 within the range of the distance X1 and is not stretched in the horizontal axis direction. It is a part. When the shape lines B and C are adopted, the length of the horizontal axis unstretched portion is extended to X2 and X3, respectively.

In the blow molding method, the resin material is oriented and crystallized by stretching to ensure heat resistance. From the viewpoint of heat resistance, the shape line having the shortest stretched portion on the horizontal axis is the shape line. It is preferable to adopt A.

(2) When the shape line A is adopted, the horizontal axis stretch ratio at the shoulder portion 30 can be maximized and the heat resistance can be improved.

In FIG. 4, the outer diameter of the preform 100 shown by the phantom line is D, and the outer diameters of the bottles on the shape lines A, B, and C corresponding to the positions at a certain distance from the support ring 20 are D3. , D2, D1. The horizontal axis draw ratios are D3 / D, D2 / D, and D1 / D, respectively. Since D1 <D2 <D3, when the shape line A is adopted, the horizontal stretching ratio at each position of the shoulder portion 30 can be maximized.

When the shape line A is adopted,
The longest horizontal axis distance from the preform outer diameter to the blow cavity surface can be secured. In the biaxial stretch blow molding method,
When the resin material is stretched in the horizontal direction, it is simultaneously stretched in the longitudinal direction. Therefore, by adopting the shape line A, the resin material in the shoulder portion can be biaxially stretched at the highest ratio.

As described above, in the blow molding method, the resin material is oriented and crystallized by biaxially stretching it in the vertical and horizontal directions, and the higher the draw ratio, the higher the crystallinity.
Therefore, adopting the shape line A can maximize the heat resistance of the shoulder portion 30.

In order to confirm the above by experiments,
Three types of bottles having shape lines A to C were molded, and the following pressure / heat resistance test was performed.

Pressure resistance / heat resistance performance test: A test bottle having a volume of 1.5 liter was pretreated and stored in a constant temperature and constant humidity of 40 ° C.-75% RH for 72 hours, and then 2.0% by a citric acid baking soda method.
Fill and cap the contents liquid to a gas pressure of kg / cm ² and 2.5 kg / cm ² (20 ° C.) and cap 65
Immerse in a water bath at ℃ for 70 minutes. After that, the test bottle was stored in a thermostatic chamber at 20 ° C. for one day and then the thermal deformation amount of the test bottle was examined.

In the above test, the conditions were set to be considerably more severe than the environmental conditions to which the bottle was actually exposed. However, the amount of thermal deformation in the shoulder portion 30 was larger in the shape line B than in the shape line C. It was found that the case was smaller, and the shape line A was smaller than the shape line B. In particular, the bottle having the shape line A which is an example of X ≦ 3 mm exhibited practically sufficient pressure resistance and heat resistance without impairing the appearance quality even under the severe conditions described above. Further, even in the bottle having the shape line B or the shape line C which is an example of X ≦ 3.5 mm or X ≦ 4.5 mm, sufficient pressure resistance and heat resistance characteristics can be secured under the environmental conditions to which the bottle is actually exposed. .

From the above, it has been confirmed that the heat resistance is better when the position where the diameter increase is started in the shoulder portion 30 is set closer to the lower surface of the support ring 20. When the position where the diameter increase is started in the shoulder portion 30 is measured by various conventional products, the support ring 20
The measurement distance from the lower surface of each was 7.14 mm. Therefore, it can be seen that the shape lines A, B, and C can sufficiently improve the heat resistance of the shoulder portion as compared with the conventional case. From this point of view, from the viewpoint of improving the heat resistance, at the position where the diameter increase starts at the shoulder portion 30, the measurement distance from the lower surface of the support ring 20 is 4.
It is preferably 5 mm or less, preferably 3.5 mm or less, and more preferably 3 mm or less.

The upper cylindrical portion 32 in the shoulder portion 30 shown in FIG. 1 has a sufficient gap space for disposing the bottle support member between the lower surface of the support ring 20 and the increased diameter portion 34. It is provided to do. From this viewpoint, it is preferable that the length of the distance X before the start of the diameter increase is equal to or larger than the plate thickness of the bottle support member.

Example 2 Next, the relationship between the heat distribution and the thickness distribution in the increased diameter portion 34 of the shoulder portion 30 was examined.

By adopting the shape line A in the first embodiment,
Moreover, by setting different bottle molding conditions, bottles having two kinds of wall thickness distributions shown in Tables 1 and 2 below were molded.

[Table 1]

[Table 2] When the thickness distribution in the increased diameter portion 34 of the shoulder portion 30 is set as shown in Table 1, the amount of thermal deformation is small even when the above pressure resistance / heat resistance test is performed, and the bottle has excellent pressure resistance / heat resistance. I was able to get Similarly, when the thickness distribution was set as shown in Table 2, a bottle having practical pressure resistance and heat resistance was obtained. However, when the thickness distribution shown in Table 2 is set, the molding stability is beginning to deteriorate as compared with the case of Table 1, and if the wall thickness in the diameter-increased portion 34 is made thinner than this, the wall thickness distribution will change at each molding. It turned out to be unstable.

Therefore, in order to improve the pressure resistance and heat resistance of the bottle, the distance from the lower surface of the support ring 20 is 5 mm.
The thickness of the shoulder portion 30 in the vicinity is approximately 1.0 to 2.
It has been found that 0 mm is preferred.

As described above, according to the second embodiment, the shape line A in which the horizontal axis unstretched portion is 3 mm or less is adopted as the shape of the shoulder portion 30, and the increased diameter portion 34 of the shoulder portion 30 is used. By setting the wall thickness in a certain range, it is possible to improve the pressure resistance and heat resistance of the bottle while ensuring molding stability.

The following method can be used to sufficiently stretch the shoulder portion 30 so that the wall thickness distribution at the increased diameter portion 34 falls within the above range.

As shown in FIG. 5, the first method is injection molding in the so-called hot parison method in which the preform 80 holding the heat at the time of injection molding is conveyed to the blow molding step to perform bottle molding. The preform 80 is conveyed to the temperature control step while the neck portion 90 is held by the neck die 90 and has the retained heat at the time of injection molding. In this temperature control step, as shown in FIG. 5, in the temperature control pot 92 zone-divided in the longitudinal direction of the preform 80 having the retained heat at the time of injection molding, a temperature distribution that provides an appropriate stretching temperature is provided. You can At this time, the temperature control zone 92a for controlling the temperature of the support ring lower region 82 of the preform 80 is set to a higher temperature than the other temperature control zones 90, so that the region 82
Can be sufficiently stretched during blow molding.

The second method is to set the support ring lower region 82 shown in FIG. 5 to be thicker than the other regions when the hot parison method is similarly adopted. Since this region 82 is thick, the heat capacity is large, and the retained heat at the time of injection molding becomes higher than other regions. Therefore, the lower area 8 of the support ring having a high heat retention
No. 2 can be sufficiently stretched during blow molding.

The third method is the so-called cold parison method in which the preform after injection molding is once stored, and then the preform at room temperature is heated to a proper drawing temperature and conveyed to the blow molding step for bottle molding. The support ring lower region 82 shown in FIG. 5 is set to be thinner than the other regions. In this case, the area 82 has a smaller heat capacity than the other areas because it is thinner, and the temperature rise when heating the preform from room temperature becomes faster. Therefore,
This area 82 has a higher heat retention during blow molding than the other areas, and can be sufficiently stretched during blow molding.

Example 3 The shape of the pressure-resistant and heat-resistant bottle in the third example is the same as that of the first example (FIGS. 1 to 3), and the shape line A in FIG. 4 is adopted. Furthermore, in the third embodiment, attention is paid to the weight ratio of the bottom portion 50 to the entire bottle.

With the total weight of the pressure-resistant and heat-resistant bottles kept constant, the same pressure-resistant and heat-resistant performance test as in Example 1 was conducted using test bottles whose bottom weights were changed as shown in Table 3, and the heat of each bottom was The amounts of deformation were compared and the results shown in Table 3 were obtained. The shape of the container used in the experiment has a total height L = 305 mm in FIG. 1, a maximum diameter D _max = 93.5 mm, and a capacity of 1.5 liters.

[Table 3] That is, when the bottom portion 50 was 19.2% by weight with respect to the entire bottle, the deformation of the bottom portion was remarkably impractical. It was also found that when the weight% of the bottom portion is 40.8% by weight, the wall thickness under the support ring 20 becomes too thin and the molding tends to be unstable. This is as mentioned above
This is because when a preform having a constant weight is biaxially stretched to obtain a bottle, there is a correlation between the wall thicknesses of the shoulder portion 30 and the bottom portion 50 of the bottle. On the other hand, the bottom 5
0% by weight are 26.2, 28.6, 30.8,
In each of the cases of 31.2 and 32.8%, the amount of thermal deformation was limited to a practically acceptable range, and the molding stability could be secured.

Therefore, in order to obtain practically sufficient pressure resistance and heat resistance, it was found that the weight ratio of the bottom portion 50 to the entire bottle is preferably about 20 to 40% by weight. Thereby, the thickness of the bottom portion 50 can be ensured to be thick enough to obtain heat resistance.

It should be noted that the improvement of the pressure resistance and heat resistance (particularly the heat resistance) of the bottom portion 50 of the pressure resistant and heat resistant bottle is complicated because the structure of the bottom portion 50 has the legs 60. Method is difficult. On the other hand, as in the third embodiment, the reinforcement by increasing the wall thickness of the bottom portion 50 is the best measure because it enhances the heat resistance at the bottom portion of the self-supporting bottle having the leg portions. This is also clear for the following reasons. That is, in order to increase the heat resistance of the shoulder portion 30 as described above, it is preferable to further stretch the shoulder portion 30 to reduce the thickness thereof, and to reduce the amount of resin saved by reducing the thickness of the shoulder portion 34 to the bottom portion. The heat resistance of the bottom part 50 can be secured by distributing the heat resistance to the 50 parts. Therefore, there is an advantage that the weight ratio of the bottom portion, which is a feature of the third embodiment, can be easily realized by carrying out in combination with the first embodiment.

In carrying out the third embodiment, it is necessary to increase the wall thickness of the valley portion 68 in order to increase the pressure resistance at the bottom of the bottle.
It is preferable for improving heat resistance. The valley 68 is the leg 6
The stretching ratio is lower than 0 and the thickness is thicker than that of the leg portion 60 by that amount, but in order to further increase the thickness, it is preferable to form the temperature distribution at the bottom portion during temperature control of the preform. That is, if the region corresponding to the valley portion 68 has a lower temperature than the region corresponding to the leg portion 60, the valley portion 68 of the bottle obtained by blow molding this preform may have a thicker wall. it can.

Example 4 The shape of the pressure and heat resistant bottle in this fourth example is the same as that of the first example (FIGS. 1 to 3), the shape line A in FIG. 4 is adopted, and the bottle molding material is further used. The heat resistance is improved by using a mixed material obtained by dry blending PET and a polyarylate resin.

Using the test bottles A to E shown below,
The same pressure resistance and heat resistance performance tests as in Example 1 were conducted to examine the total height of each test bottle and the amount of thermal deformation at the mutation site. The results are shown in Tables 4 and 5.

[Table 4]

[Table 5] Test bottle; A: PET having the shape of Example 1 with X = 2.87 mm
Bottle B: PE having the shape of Example 1 with X = 2.87 mm
T98% by weight and polyalate resin (Unitika Ltd.)
"U-8400" manufactured by the company) 2% by weight of bottle C: PE having the shape of Example 1 with X = 2.87 mm
A bottle consisting of 96% by weight of T96 and 4% by weight of a polyalate resin. D: PET having a shape different from that of Example 1 with X = 7.14 mm, PET95. Bottle made of 2% by weight and 4.8% by weight of polyalate resin E: PET bottle having a shape different from that of Example 1 with X = 7.14 mm From the results in Table 4, the internal gas was changed by changing the shape. The pressure of 2.0 kg / cm ² can be cleared, but 2.5 k
It has been found that it is necessary to dry blend 4% by weight or more of the polyarylate resin in order to satisfy the condition of g / cm ² .

From the results shown in Table 5, it was found that it is necessary to dry-blend the polyarylate resin in an amount of 4% by weight or more in order to prevent the bottom portion from being deformed.

Below the neck 10 (support ring 20
In order to prevent the deformation of (below), it is not enough to dry-blend the polyarylate resin in an amount of 4% by weight or more, and it is a very important factor to make the shape of the shoulder portion 30 as in Example 1. It was also found that

Here, as the weight% of the polyarylate resin mixed with PET is increased, the heat resistance of the bottle is improved, but there is an upper limit for maintaining molding stability. That is, if the weight percent of the polyarylate resin exceeds 10 weight percent, it is difficult to maintain molding stability. this is,
This is because PET and polyarylate resin have different softening points and different drying rates. Each resin material is
It is dried at the same time by the drying device, put into the hopper of the injection device, and melted by heat, but the dwell time in the drying device or hopper differs for each lot or shot due to the difference in the drying speed and the difference in the softening point. As a result, when the polyarylate resin exceeds 10% by weight, the molding stability is markedly deteriorated and, for example, the dimensional stability is impaired. In this sense, 3-10% by weight of polyarylate resin and PE
By molding a bottle with a synthetic resin containing T97 to 90% by weight, heat resistance is improved and molding stability can be maintained as compared with PET alone.

The present invention is not limited to the above embodiments, and various modifications can be made within the scope of the present invention. For example, as the bottom structure of the pressure-resistant and heat-resistant bottle to which the present invention is applied, the above-described five leg portions 60 are used.
However, it is not limited to one having at least three legs 60 of an odd number or even number.

The portions other than the characteristic shape of the shoulder portion 30 described in the first embodiment can be appropriately modified into various other shapes.

[0071]

As described above, claim 1 or 2
According to the invention, the length of the unstretched region in the horizontal axis direction from the lower surface of the flange portion to the diameter increasing start position can be set as short as within 4.5 mm or 3 mm, and the diameter increasing start position is on the flange portion side. The closer to, the higher the horizontal axis draw ratio of the increased diameter portion of the shoulder portion, the higher the orientation crystallization, and the higher the heat resistance of the shoulder portion. Therefore, even if it is a large bottle with a volume of 1 liter or more,
By using a self-standing bottle having a plurality of legs, pressure resistance can be ensured and heat resistance at the shoulder can be improved.

According to the third or fourth aspect of the present invention, by reducing the thickness of the shoulder portion so that the heat resistance can be secured, the saved resin can be distributed to the bottom portion, and the thickening of the bottom portion allows mechanical reduction. It is possible to provide a bottle that has high strength, ensures heat resistance at the bottom of a complicated shape having legs, and has high molding stability.

According to the invention of claim 5, higher heat resistance can be ensured and molding stability can be ensured by using a mixed material of PET resin and polyarylate resin.

[Brief description of drawings]

FIG. 1 is a schematic front view showing a pressure-resistant and heat-resistant bottle according to an embodiment of the present invention.

FIG. 2 is a schematic bottom view showing the bottom of the pressure-resistant and heat-resistant bottle shown in FIG.

FIG. 3 is a schematic cross-sectional view showing an AA cross section of FIG.

FIG. 4 is a schematic explanatory view showing the shape under the neck of the pressure-resistant and heat-resistant bottle according to Example 1.

FIG. 5 is a schematic cross-sectional view showing a temperature control step of the preform.

[Explanation of symbols]

 10 Neck part 20 Support ring (flange part) 30 Shoulder part 32 Cylindrical part (horizontal axis unextended part) 40 Body part 50 Bottom part 52 Heel part 60 Leg part

Front page continued (72) Inventor Yoichi Tsuchiya 4586 Ko, Komoro, Nagano 3 Nissei ASB Machinery Co., Ltd. (72) Inventor Tsuyoshi Kage 6-26-1, Jingumae, Shibuya-ku, Tokyo Kirin Brewery Co., Ltd. (72) Inventor Minoru Okada 6-26-1, Jingumae, Shibuya-ku, Tokyo Kirin Brewery Co., Ltd. Within

Claims (5)

[Claims] 1. A neck portion having a flange portion projectingly formed, a shoulder portion having a portion formed continuously with the neck portion and increasing in diameter downward from an outer diameter immediately below the flange portion, and the shoulder. And a bottom portion that is formed so as to close the lower end of the body portion and that includes at least three or more self-standing legs, and a shoulder portion other than the neck portion. In a pressure-resistant and heat-resistant bottle made of synthetic resin in which the body and the bottom are obtained by blow molding, the shoulder portion has a shape in which the diameter increase starts from a position within a distance of 4.5 mm from the lower surface of the flange portion. A pressure resistant and heat resistant bottle characterized by having. 2. The pressure-resistant and heat-resistant bottle according to claim 1, wherein the shoulder portion has a shape in which the diameter increase starts at a position within a distance of 3.0 mm from the lower surface of the flange portion. 3. The pressure resistance and heat resistance according to claim 2, wherein the thickness of the shoulder portion is approximately 1.0 to 2.0 mm at a position at a distance of 5 mm from the lower surface of the flange portion. Bottle. 4. The weight according to claim 2, wherein the bottom portion has a heel portion whose diameter decreases from the outer diameter of the body portion toward the ground contact surface of the leg portion, and the weight of the bottom portion including the heel portion. Has a ratio of 20 to 40 to the total weight of the bottle.
A pressure-resistant and heat-resistant bottle characterized by a weight percentage. 5. The synthetic resin according to claim 1, wherein the synthetic resin comprises 3 to 10% by weight of a polyarylate resin having a glass transition temperature of 185 to 195 ° C. and 97 to 90% by weight of a polyethylene terephthalate resin. Withstand pressure and heat resistant bottle.