JP2541401B2 - Highly stretch blow molded container and its manufacturing method - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a highly stretch blow-molded container which is thin and has no uneven thickness and whitening, and a method for producing the same.

[0002]

2. Description of the Related Art A container obtained by biaxially stretch-blow molding a preform by a device using a stretching rod for forcibly stretching in the height direction is well known before the present application. However, it has been unknown at all to manufacture a biaxially stretch-blow-molded container and a container in this way using only a pressurized fluid, which is substantially unconstrained. The present inventor has previously clarified that a container having excellent performance can be obtained by this unconstrained high stretch blow molding, and completed the invention of unconstrained high stretch blow molding. Further research was continued to improve the present invention, and invented an unconstrained high stretch blow molding container having a uniform film thickness in which at least one of the mouth neck portion and the center portion of the bottom is thermally crystallized and the other container wall is crystallized. Further research was conducted to complete the present invention.

[0003]

The conventional biaxially stretch-molded container using the above-mentioned stretch rod has the drawback of a low draw ratio and a large uneven thickness, and its strength is non-uniform and small. Inevitably, whitening was also likely to occur, which was not satisfactory.

[0004]

The present inventor has solved the above problems by elucidating that such a defect occurs because the resin layer of the container wall of the molded container is not sufficiently and uniformly stretched, The present invention has been completed by successfully providing a highly-stretched thin-walled lightweight container having uniform thickness without uneven thickness and whitening, and free from neck bending and cracking.

1. Except for the mouth and neck, the film thickness of the stretch-formed container wall is almost uniform, and the ratio of the thickest part of the film to the thinnest part of the film is 1.0 to 2.0. ,
A blow-molded container in which the bottom is highly stretched and the vessel wall excluding the mouth and neck is oriented and crystallized, and the stretch orientation crystallinity of the joint from the shoulder to the mouth and neck is 20% or less. Blow molded container. 2. The wall thickness of the vessel wall stretch-molded excluding the mouth and neck is almost uniform, and the ratio of the thickest part to the thinnest part is 1.0 to 2.0, and the part excluding the mouth and neck is used. A polyethylene terephthalate resin blow-molded container in which the wall is stretch-oriented and crystallized, and a shoulder portion, a body portion, and a bottom portion are highly stretched,
A high-stretch blow-molded container in which the container wall of the inflection portion from the shoulder to the mouth and neck is formed by arranging the 010 face of the polyethylene terephthalate resin crystal in the direction normal to the wall surface of the container. 3. 3. A high-stretch blow-molded container described in item 1 or 2 in which the ratio of the amount of resin to the internal volume in the stretched portion of the container is 0.025 or less in terms of a 1.5-liter container and there is no whitening. A high-stretch blow-molded container described in any one of items 1 to 3 , which has a thin wall thickness of 0.2 mm to 0.3 mm as measured on the body and is free from uneven thickness and whitening. 5. Except for the thermally crystallized part of the mouth and neck and the center of the bottom
The film thickness of the stretch-formed container wall is almost uniform,
The ratio of the thickest part of the film to the thinnest part of the film is 1.0 to 2.0
Yes, the shoulder, torso, and bottom are highly stretched, and the mouth and neck are removed.
The container wall was a blow-molded container whose orientation was crystallized,
20% stretch orientation crystallinity of the connection from the shoulder to the mouth and neck
The following high stretch blow molded containers . 6. By pressurizing the fluid without restraining the preform, at least 9 of the maximum stretched portion in the radial direction of the body of the molding container is obtained.
High stretch blow molding of 0% or more in an unrestrained state
The trunk and the bottom are highly stretched, the stretch-oriented crystallinity of the connection from the shoulder to the mouth and neck is set to 20% or less, and the ratio of the thickest film portion to the thinnest film portion is 1.0 to 2. A method for producing an unconstrained high-stretch blow-molded container, characterized in that the container wall other than the neck and neck is oriented and crystallized to make the film thickness of the stretch-molded container wall substantially uniform. 7. By pressurizing fluid without restraining the preform, at least 90% or more of the maximum stretched part in the radial direction of the body of the molding container is subjected to high stretch blow molding in an unconstrained state to raise the shoulder, body, and bottom. Extend and add 01 of polyethylene terephthalate resin crystals to the wall of the inflection part from the shoulder to the mouth and neck.
The 0 surface is arranged in the direction normal to the wall surface of the container, and the film is stretch-molded so that the wall thickness of the container is substantially uniform, and the ratio of the thickest part to the thinnest part is 1.0 to 2.0. A method for producing an unconstrained high stretch blow-molded container, characterized in that 8. The method for producing an unconstrained high stretch blow-molded container according to item 6 or 7, wherein a preform in which at least one of the mouth neck part and the center of the bottom part is thermally crystallized is used. 9. The stretching of the preform is finally carried out with a stretching ratio in the radial direction of 4.5 to 5.5 and a stretching ratio in the radial direction of 1.5 to 1.8 of the stretching ratio in the height direction. , 6
Item 9. A method for producing an unconstrained high stretch blow-molded container according to any one of items 1 to 8.

The high stretch blow-molded container referred to in the present invention means
The film thickness of the stretch-formed container wall other than the mouth and neck is almost uniform, the ratio of the film thickness between the thickest part and the thinnest part is 1.0 to 2.0, and It is a high stretch blow-molded container in which the container wall except for the above is crystallized by orientation and the stretch-oriented crystallinity of the connecting portion from the shoulder to the mouth and neck is set to 20% or less. In such a container of the present invention, 90% or more of the maximum stretched portion in the radial direction of the body of the container is not constrained by the pressurized fluid without constraining the preform other than the mouth and neck, and high stretch blow molding is performed. The stretch-oriented crystallinity of the connection portion from the shoulder portion to the mouth-neck portion obtained by the method can be 20% or less.

A high-stretch blow-molded container has a substantially uniform film thickness on the stretch-molded container wall other than the neck and neck,
The film thickness ratio between the thickest part and the thinnest part is 1.
0 to 2.0, and the vessel wall excluding the mouth and neck and, if necessary, the center of the bottom is oriented and crystallized, and the vessel wall at the inflection portion from the shoulder to the mouth and neck is made of polyethylene terephthalate resin crystals.
It is a high-stretch blow-molded container in which 0 surface is arranged in the direction normal to the wall surface of the container.

As described above, in the conventional biaxial stretch blow molding, not only the pressurized fluid but also the stretch rod is used in the height direction to perform the stretch molding. That is, the stretch forming in the height direction is a stretch forming constrained by a stretch rod, and is not a substantially stretch-free high stretch blow forming by a pressurized fluid. And
If stretching is performed while restraining the height direction, stretching in the circumferential direction is also affected. In this conventional stretch-blow molding, the circumferential direction of the container is further constrained by a mold for molding. Since it is required for the container to have a good outer shape, there is a tendency to make efforts only to improve the outer shape, and the strength of the container tends to depend on the thickness of the vessel wall. Therefore, the circumferential stretching of the container was not sufficient.

On the other hand, in the high stretch blow molding of the present invention, at least 90% or more of the maximum stretched portion of the preform in the radial direction of the body portion is subjected to high stretch blow molding with a pressurized fluid without restraint to form a preform. The ratio of the thickest part and the thinnest part is 1.0-
A container with a stretched orientation crystallinity of 20% or less at the connecting portion from the shoulder to the mouth and neck is formed.

[0010]

The conventional stretch blow molding is a molding which prevents free stretching of the vessel wall as described above. Since free stretching is not allowed and a force is applied to a part of the vessel wall to stretch the whole, the force applied to the vessel wall differs depending on the portion of the vessel wall, and the portion with a large force becomes thin, The thin portion is thick and cannot be stretched uniformly. On the other hand, when the fluid is highly stretched without restraint, the same force acts on the entire vessel wall, and the vessel wall is similarly stretched. The thicker film, in other words, the more resin, is further stretched so that the film thickness becomes uniform. As described above, the stretching mechanism is completely different between constrained stretching and unconstrained stretching.

In the present invention, stretch-blow molding performed without restraint means that at least 90% or more of the maximum stretched portion in the radial direction of the body of the container is blow-molded without restraint. It is most preferable to perform completely unconstrained until the completion of the container, but when unconstrained blow molding, the container approaches a spherical shape, but each container has the required outer shape, so at the final finishing stage, the outer shape is determined by the mold. Although it can be restrained and arranged, in the present invention, it is important that the stretch forming in the unconstrained state of the vessel wall is performed without restraining at least 90% or more of the maximum stretched portion in the radial direction of the body of the molding container. .

Theoretically, the container receives a stress of 2 in the circumferential direction with respect to the height direction of 1 in the cylindrical body. That is, the body of the container receives twice the stress in the circumferential direction as compared with the height direction. Further, as can be understood from the fact that the shoulders and the bottom have a substantially spherical shape, they are subjected to a small stress which is almost the same as in the height direction. Therefore, in order to increase the strength of the container, it is absolutely necessary to increase the pressure resistance in the circumferential direction of the body, and if the pressure resistance in the radial direction of the container body can be increased, the wall thickness of the container can be reduced. Therefore, the amount of resin can be reduced. In this case, what is important is that the film thickness is uniform, and if the film thickness is non-uniform, the pressure resistance of the container is determined by the weakest part, and the container does not become uniform and have high pressure resistance. However, this requirement cannot be satisfied by the conventional biaxial stretch blow molding. As described above, in conventional stretch-blow molding, a force is applied to a part of the vessel wall to stretch the entire vessel wall. It is not uniform on the vessel wall, there are partial differences, uniform stretching is not possible, and the film thickness is also non-uniform. Therefore, a uniform and highly pressure-resistant container cannot be obtained.

In the high stretch blow molding of the present invention, it is necessary to blow mold at least 90% or more of the maximum stretched portion in the radial direction with a pressurized fluid, particularly a high pressure fluid, in an unconstrained state. And 90% of the stretching in the height direction excluding the mouth and neck, which is the non-stretched portion
It is optimum to perform the above-mentioned unconstrained high stretch blow molding.
That is, it is most preferable that 90% or more of the entire molding process is performed in the unconstrained state by the time of the finishing process of contacting the blow mold and forming the shape of the container. Molding temperature 90-130
Most preferably, high stretch blow molding is performed using a fluid at a temperature of 3 to 40 kg / cm ^{2 at} a temperature of ℃.

As described above, the substantially unconstrained high stretch blow molding allows the stretch to be sufficiently stretched which cannot be predicted by the conventional stretch blow molding, so that the thickness of the vessel wall becomes substantially uniform and the thickest portion and the thinnest portion are formed. Thickness ratio is 1.0 to 2.0
The performance of the neighboring wall is dramatically improved. If the ratio of the thickness of the thick portion to the thickness of the thin portion exceeds 2.0, the vessel wall cannot be said to be sufficiently uniform and the performance is poor.

The present invention also includes a container in which the mouth and neck and the center of the bottom are thermally crystallized. When unconfined biaxially stretch blow-molded, the bottom part is also biaxially stretched and the center part is oriented and crystallized, but the bottom part of the container is at a high risk of being impacted during filling or during the distribution process. It may be required to provide a section. In order to meet this requirement, if a preform provided with a thermal crystal region in the center of the bottom is used, it is difficult to perform oriented crystallization in the conventional stretch blow molding because the vicinity of this thermal crystal region cannot be sufficiently stretched. Moreover, since it is not thermally crystallized, its strength is low. However, even if a preform having a thermal crystal region in the center of the bottom is used, stretch-blow molding can be performed without restraint, so that the vicinity of the thermal crystal region is also sufficiently stretched, oriented crystals are formed, mechanical strength is increased, and internal pressure resistance is also high. Very good. Even in the case where the bottom center portion is thermally crystallized, the strength of the container does not increase unless the vessel wall of the entire container is sufficiently stretched and oriented. Therefore, it is an absolute requirement that high stretch blow molding should be performed unconstrained.

It is optimal to perform unconstrained high stretch blow molding for 90% or more of the stretching in the height direction. That is, it is most preferable that 90% or more of the entire molding process is performed in the unconstrained state by the time of the finishing process of contacting the blow mold and forming the shape of the container. Therefore, when the blow mold is brought into close contact with the blow mold in the finishing process, 90% of the maximum extending portion in the radial direction of the container body is obtained.
It is preferable to design the shape of the preform in advance so that at least 100% is blow-molded in an unconstrained state. In this way, by substantially unconstrained high stretch blow molding, the thickness of the vessel wall becomes almost uniform, and the ratio of the film thickness between the thickest portion and the thinnest portion becomes 1.0 to 2.0, and the performance of the vessel wall jumps. Improve. If the ratio of the thickness of the thick portion to the thickness of the thin portion exceeds 2.0, the vessel wall cannot be said to be sufficiently uniform and the performance is poor. In addition, since it is sufficiently stretched to almost a saturated state by unconstrained high stretch blow molding, the yield value in the circumferential direction of the body resin layer is 1800 kg /
cm ² or more, and the yield value in the height direction is 800 kg / c
A highly stretched highly stretched container of m ² or more is formed.

Such a container having a uniform thickness and having a stretched orientation crystallinity of 20% or less at the connecting portion from the shoulder portion to the mouth and neck portion is a novel container which is not known at all before the present application. INDUSTRIAL APPLICABILITY The unconstrained high-stretching container of the present invention has a novel high strength in which the yield value in the circumferential direction of the body resin layer of the vessel wall is 1800 Kg / cm ² or more and the yield value in the height direction is 800 Kg / cm ² or more. This is a high stretch container with a yield value of 500kg at best.
It is understood that the container of the present invention is also a container having a container wall of a highly stretched and highly oriented crystallinity and a special resin layer having an extremely high yield value even from the viewpoint of about / cm ² .

The yield value referred to in the present invention is that the permanent deformation starts to increase sharply as the stress slightly increases as the stress gradually increases in the process of deforming the container wall by applying stress. It is a value of stress, using Tensilon UTM-III-100 manufactured by Toyo Baldwin Co., Ltd. as a tester, and a test piece was punched with a shape according to JIS K7113 or ASTM D638, and the height direction and the circle from the body of the container were measured. A test piece punched in the circumferential direction was tested at a speed of 10 mm / min to obtain a yield value. Therefore, a high yield value means that the stress that causes permanent deformation is large and that the mechanical strength is large. This indicates that the container is unlikely to be deformed due to expansion due to internal pressure during storage. If the shoulder needs to have a specific shape, it may be formed by touching a blow mold. This is because the shoulder portion is different from the body portion in that the applied internal pressure is small, and thus the container is not affected even if the degree of stretching is low and the yield value is small by performing the molding with some restraint.

In the conventional biaxially stretch blow-molded container, when the contents are filled and stored, stress cracking occurs from the shoulder to the mouth and neck, the neck is tilted, and the neck height is changed. As a result of studying in consideration of this point, the oriented crystallinity of the connection part from the shoulder to the mouth and neck is 20%.
It has been found that the following can prevent the occurrence of stress cracking, neck bending, change in neck height, etc. even with a positive pressure container.

The highly stretch-molded container of the present invention has a stretch-oriented crystallinity of 20% or less at the connection portion from the shoulder to the mouth and neck, preferably 4 to 20%, and 7 to 18%. Most suitable. It was also found that in the cracks, the benzene plane of the polyethylene terephthalate crystals was oriented perpendicular to the wall of the container. Further research showed that when the container was filled with contents and the internal pressure increased,
It was found that the peaks of 0-face, 110-face, and 100-face increased, and that when cracks occurred, the 010-face increased, especially at the upper end of the crack. Thus, it is understood that cracking occurs when the 010 plane increases after filling.

The present inventor has found that polyethylene terephthalate crystals on the vessel wall of the inflection portion from the shoulder to the mouth and neck of the container are 010
The surface is placed opposite the central axis of the container, ie 01
By arranging the 0 plane parallel to the wall of the container, we succeeded in preventing the occurrence of cracks. The X-ray diffraction intensity in the examples described later is PSPC manufactured by Rigaku Denki Co., Ltd.
/ MDG system, X-rays were made incident on the container wall perpendicularly, and measurement was carried out by the transmission method. The target used was copper and the collimator diameter was 50 μm. The degree of orientation (F) is obtained by differentially measuring the X-ray diffraction intensity in the circumferential direction of the container wall, and determining the intensity derived from the crystal lattice planes (010) and (110) as P (01
0), P (110),

[0022]

[Equation 1]

It is defined as

When the degree of orientation of the container wall is 0.6 or more, stress cracking resistance is improved and cracks are eliminated.
Furthermore, the stretch orientation crystallinity of the connection part from the shoulder to the mouth and neck is 2
When the content is 0% or less, cracking and neck bending can be prevented. The first characteristic of the present invention is that the film thickness of the vessel wall formed by extension except the mouth and neck is substantially uniform.

The second feature of the present invention is that the ratio of the film thickness between the thickest part and the thinnest part of the vessel wall other than the mouth and neck is 1.0 to.
It is 2.0. When the ratio of the film thickness exceeds 2.0, the pressure resistance strength becomes uneven and the container becomes distorted. The third feature of the present invention is that all the vessel walls except the central portion of the mouth are highly oriented and crystallized, and the yield value is very high. Due to this feature, high compressive strength and buckling strength are obtained, and there is an effect that there is little shrinkage over time.

The fourth feature of the present invention is that the stretch-oriented crystallinity of the connecting portion from the shoulder portion to the mouth-neck portion is set to 20% or less. The container wall of the inflection portion from the shoulder to the mouth and neck of the container is that the 010 plane of the polyethylene terephthalate resin crystal was arranged in the direction normal to the wall surface of the container. With this feature, it is possible to prevent stress cracking, neck bending, change in neck height, and the like. As a fifth feature of the present invention, by arranging the thermal crystal part in the center of the bottom, the bottom can withstand the impact received during handling. The sixth feature of the present invention is that the gas barrier property of the vessel wall is excellent, and in particular, the permeation of oxygen is small. This feature prevents the contents from being deteriorated by oxygen, and produces an effect that the contents are not degassed . The present inventor believes that the gas barrier property is improved as described above because the oriented crystallization progresses and the crystallinity increases as the molecular orientation increases.

The highly stretchable container of the present invention has a volume of 1.5 liters.
The ratio of the amount of resin (g) in the stretched portion to the internal volume (cc) of the container in terms of container is 0.025 or less, preferably 0.00
5 to 0.025, and the resin is 20 compared to the conventional container.
The effect is that it is less than -50% and the strength is equal or higher. It is most preferable to perform completely unconstrained up to the completion of the container, but if unstretched and high stretch blow molded, the container approaches a spherical shape depending on the shape of the preform, however, each container has an external shape required. At the final stage of finishing, the outer shape can be constrained by a mold and arranged,
In the present invention, it is important that the high stretch molding of the container wall in the unconstrained state is performed without restraint in at least 90% or more of the maximum radially stretched portion of the body of the molding container.

When high stretch blow molding is performed with unconstrained pressurized fluid, the preform is first stretched in the radial direction regardless of temperature, pressure and wall thickness. The stretching ratio in the radial direction is 4.5 to 5.
It is 5. In comparison with the conventional biaxial stretch molding, in which the stretching ratio in the radial direction was at most 4.2, the stretching effect is extremely high when the present invention is substantially unconstrained and the high stretch blow molding is performed only by the pressurized fluid. It is understood that it is good. When the stretching ratio is within this range, whitening of the container and uneven thickness can be prevented. When the radial stretching reaches the above range,
Stretching in the height direction is promoted, but stretching in this direction is also unconstrained and is stretch blow molding with a pressurized fluid. The draw ratio in the radial direction is 1.5 to 1.8 of the draw ratio in the height direction.
When the stretching ratio in the height direction is within this range, whitening of the container and uneven thickness can be prevented.

When the stretching in the height direction reaches approximately the above range, the container hits a predesigned mold and the outer shape is adjusted. If you want to keep the position of the center of the bottom of the obtained container constant, for example, by fixing the center of the bottom of the container to the center of the bottom of the blow mold with a fixture installed inside the container that is preformed in the final step. It is possible to perform blow molding for finishing, but if it is not necessary to keep the position of the center of the precise bottom constant, it is not necessary to perform such centering process. As described above, it is clear that the stretch ratio is very different from the conventional biaxial stretch molding using a stretch rod by stretch blow molding with a pressurized fluid with substantially no constraint, but it is easy to understand. In terms of the area stretching ratio, which is the product of the stretching ratio in the radial direction and the stretching ratio in the height direction, the surface stretching ratio is about 10 in the conventional biaxial stretching molding container, but in the high stretching molding container of the present invention. 12
It is about 20 to 20 and is as high as 20 to 100%. For this reason, it is highly oriented and has a high degree of oriented crystallinity, a high yield value, and a very high container strength. The conventional method uses polyester with a container weight of 50 g and an internal volume of 1500 ml.
When the container of the present invention is compared with the container of the present invention having the same shape using a polyester having a weight of 36.4 g, the container of the present invention shows the same or higher mechanical strength although the resin amount is only 73%.

When the preform is heated from both the outside and inside in the case of substantially stretch-free high stretch molding, the heating becomes uniform, which is extremely suitable and effective for high stretch blow molding. This increases the draw ratio in order to increase the strength of the container, but because of this the wall thickness of the preform becomes large, the internal temperature becomes low only by external heating due to normal heating, This is because there is a tendency that sufficient stretching cannot be performed, uneven thickness or whitening occurs, and a good container cannot be obtained. The container of the present invention has a 010 inflection part from the shoulder to the mouth and neck.
Since the surface is parallel to the wall, cracks do not occur, the yield value is large, and the internal pressure resistance is extremely excellent, it is suitable for a container for gas-containing beverages.

The preform used in the present invention is preferably made of a thermoplastic polyester, but in addition to this, a polyester as a main material, for example, a saponified ethylene-vinyl acetate copolymer, a polyvinylidene chloride resin, Barrier properties such as copolymers containing acrylonitrile or methacrylonitrile as the main component, aromatic nylon, nylon 6, nylon 66, nylon 11 etc., barrier properties such as polyethylene terephthalate / ethylene isophthalate, etc. Gas barrier properties such as copolyester A preform in which substances are blended or laminated, or a polyester as a main material and a small amount of a copolymer or blend of a resin such as ethylene glycol, isophthalic acid, benzoic acid, naphthalene 1.4 dicarboxylic acid, or naphthalene 2.6 dicarboxylic acid Formed by things Preform is also included.

[0032]

EXAMPLES The effects of the present invention will be described with reference to specific examples.

Example 1 Wall thickness 4.56 mm molded from polyester, resin amount 3
Using 6.4 g of thick preform, uniformly heated to 120 ° C. from both inside and outside, and practically unconstrained under the conditions shown in Table 1, high stretch blow molding to obtain an internal volume of 1500 m
A container containing m was manufactured.

Example 2 Thickness 4.56 mm molded from polyester, resin amount 3
Using 6.4 g of thick-walled preform with heat-crystallized mouth neck and center of bottom, heat crystallized mouth neck and center of bottom, uniformly heat to 120 ℃ from both inside and outside, Under the conditions shown in Table 1, a container having an inner volume of 1500 ml was manufactured.

Comparative Example 1 4.20 mm thick resin formed from polyester with a resin amount of 5
Using a thin preform of 0.0 g, a biaxial stretch molding using a stretch rod under the conditions shown in Table 1 to obtain an inner volume of 1500
A container containing ml was manufactured.

Comparative Example 2 Molded with polyester, wall thickness: 4.20 mm, resin amount: 5
A container having an internal capacity of 1500 ml was manufactured under the conditions shown in Table 1 using 0.0 g of the thin preform.

Comparative Example 3 Thickness of 4.20 mm molded from polyester, resin amount 3
A container having an inner volume of 1500 ml was manufactured under the conditions shown in Table 1 using 6.4 g of the thin preform. But,
The body was whitened and did not function as a product. This comparative example is not a conventional example, but an example in which only the amount of resin is the same as that of the example for the purpose of comparison.

Comparative Example 4 Polyester-molded wall thickness 4.56 mm, resin amount 3
A container containing 1500 ml of internal volume of 6.4 g of thick-walled preform, which was heated at 100 ° C. and blow blown under the conditions shown in Table 1 immediately after being blown to be stretch-blow molded while being axially stretched by a stretching rod. Was manufactured. Examples 1 and 2
Table 2 shows the performances of the containers of Comparative Examples 1, 2, 3 and Comparative Example 4.

[0039]

[Table 1]

* 1: Polyester resin manufactured by Mitsui Petrochemical Co., Ltd. * 2: Polyester resin manufactured by Eastman Kodak Co., Ltd. * 3: Obtained by subtracting 8 g of the weight of the mouth and neck and the center of the bottom. * 4: Average of the values measured at 4 locations in the circumferential direction on the body of 10 containers each.

[0041]

[Table 2]

(Note) * 5: Toyo Baldwin Tensilon UTM-III-100 was used as a tester, and the test piece was JISK71.
A test piece punched in the height direction and the circumferential direction from the body of the container was tested at a speed of 10 mm / min with a punching blade having a shape conforming to the standard of 13 or ASTM D638, and the yield value was obtained.

[0043]

[Equation 2]

Σ ... Yield value F ... Load A ... Original average cross-sectional area of the parallel part of the test piece * 6: An n-heptane-carbon tetrachloride-based density gradient tube (Ikeda Rika Co., Ltd.) was prepared and the temperature was 20 ° C. The density of the sample was obtained under the conditions, and the crystallinity was calculated according to the following formula.

[0045]

(Equation 3)

D: Density of sample (g / cm ³ ) * 7: Voids are generated and a satisfactory product cannot be obtained. * 8: The container wall is cut out and the Modern Cont
roll company (Oxytran-100) at 25 ° C., 1
The oxygen permeability QO ₂ (c
c / m ² · day · atm) was measured. * 9: Oxygen permeability coefficient PO of the thickness of the container body wall per unit
₂ (cc · cm / cm ² · sec · cmHg) was calculated from the oxygen permeability. * 10: Use an empty container 24 hours or more after molding,
Carbonated water is filled up to the line of sight, sealed with a cap, and left at room temperature for 24 hours. Therefore, after measuring the height of the container and the diameter of the body, the same portion after storing at 38 ° C. for 24 hours was measured and the pressure resistance was evaluated from the rate of change. * 11: 1500 g of 4 gas volumes of carbonated water in a container
It is filled with ml and sealed, and stored in an atmosphere of 30 ° C. and 80% RH for 1 week, and the occurrence of stress cracking is observed. n =
10 bottles * 12: 1,500 carbonated water of 4 gas bottles in a container
It is filled with ml and sealed, stored at 5 ° C. for 1 week, and dropped onto a concrete from a height of 2 m for evaluation. n = 10

[Evaluation] As described above, 90% or more of the maximum stretched portion in the circumferential direction of the body portion of the body portion resin layer that constitutes the wall of the present invention is stretched without restraint, and 90% in the height direction. The high stretch blow-molded container in which% is stretched without restraint has very good strength, so that the amount of resin used can be reduced by 20 to 50%. When the oxygen permeability coefficient PO ₂ is small, the amount of oxygen permeation can be almost the same as or smaller than that of the conventional container even if the wall thickness is made thin. From this point as well, the container of the present invention can reduce the amount of resin. Understand what you can do. By finally stretching the preform so that the stretching ratio in the radial direction is 4.5 to 5.5 and the stretching ratio in the radial direction is 1.5 to 1.8 of the stretching ratio in the height direction, the body resin A high stretch blow-molded container having a yield value in the circumferential direction of the layer of 1800 kg / cm ² or more and a yield value in the height direction of 800 kg / cm ² or more, and a stretching ratio within the above range. It is understood that if it comes off, uneven thickness and whitening occur. The container wall of the inflection portion from the shoulder to the mouth and neck is arranged such that the 010 plane of the crystal of polyethylene terephthalate resin is arranged in the normal direction of the wall surface of the container, and the stretch orientation crystallinity of the connection portion from the shoulder to the mouth and neck is 20. When it is less than%, stress cracking, neck bending, and neck height change are prevented.

[0048]

As described above, the present invention provides a container having a large yield value, a high draw ratio, a high strength and an excellent gas barrier property without whitening by substantially unconstrained stretch blow molding. Is. And the container of the present invention is very excellent in the pressure resistance of the body part to which the most internal pressure is applied, and in particular, it is excellent in pressure resistance at high temperature and heat pressure stability, so
It is very suitable to.

 ─────────────────────────────────────────────────── ─── Continuation of the front page (56) References JP-A-57-113033 (JP, A) JP-A-58-188630 (JP, A)

Claims (9)

(57) [Claims] 1. The film thickness of the vessel wall stretch-molded excluding the mouth and neck is substantially uniform, and the ratio of the thickest part to the thinnest part is 1.0 to 2.0. A blow-molded container in which a shoulder portion, a body portion, and a bottom portion are highly stretched, and a vessel wall excluding the mouth and neck portion is oriented and crystallized, and a stretched and oriented crystallinity of a connection portion from the shoulder portion to the mouth and neck portion is 20. % Stretch blow molding container. 2. The film thickness of the vessel wall stretch-molded excluding the mouth and neck is substantially uniform, the ratio of the thickest part of the film to the thinnest part is 1.0 to 2.0, and A polyethylene terephthalate resin blow-molded container in which the vessel wall excluding the neck portion is stretch-oriented and crystallized, and the shoulder portion, body portion, and bottom portion are highly stretched, and the container wall at the inflection portion from the shoulder portion to the mouth and neck is polyethylene. A high-stretch blow-molded container formed by arranging 010 faces of terephthalate resin crystals in a direction normal to a wall surface of the container. 3. The ratio of the amount of resin to the internal volume in the stretched portion of the container is 0.02 in terms of a 1.5 liter container.
The high stretch blow-molded container according to claim 1 or 2 , which has 5 or less and no whitening. 4. A wall thickness of 0.2 mm to 0.
Claims 1 no thin a and uneven thickness and whitening 3 mm 3
A high stretch blow-molded container described in any one of 1. 5. A thermally crystallized portion of the neck and the center of the bottom.
Except that the film thickness of the stretch-formed container wall is almost uniform.
And the ratio of the thickest part to the thinnest part is 1.0
~ 2.0, the shoulder, body, and bottom are highly stretched, and
Blow-molded container with orientation crystallized container wall excluding mouth and neck
And stretch orientation crystallization of the connection from the shoulder to the mouth and neck
High stretch blow molded container with a degree of 20% or less . 6. A high-stretch blow molding is performed without constraining the preform by using a pressurized fluid at least 90% or more of the maximum stretched portion in the radial direction of the body of the molding container in an unconstrained state,
The shoulder, body, and bottom are highly stretched, and the oriented crystallinity of the joint from the shoulder to the mouth and neck is 20% or less, and the ratio of the thickest part of the film to the thinnest part is 1.0. To 2.0, and orientation-crystallizing the container walls other than the mouth and neck to make the film thickness of the stretch-formed container walls substantially uniform, a method for producing an unconstrained high-stretch blow-molded container. 7. A shoulder and a body are subjected to high stretch blow molding without restraining at least 90% or more of the maximum stretched portion in the radial direction of the body of the molding container by the pressurized fluid without restraining the preform. The bottom and bottom parts are stretched to a high degree, and the 010 face of the polyethylene terephthalate resin crystal is placed in the container wall of the inflection part from the shoulder to the mouth and neck in the direction normal to the wall surface of the container, and stretch-molded. Is substantially uniform, and the ratio of the thickest part of the film to the thinnest part of the film is 1.0 to 2.0. 8. A preform in which at least one of the mouth and neck and the center of the bottom is thermally crystallized is used.
A method for manufacturing the unconstrained high stretch blow-molded container according to claim 6. 9. The preform is finally stretched to a radial stretch ratio of 4.5 to 5.5 and a radial stretch ratio of 1.5 to 1.8 as a height stretch ratio. The method for producing an unconstrained high stretch blow-molded container according to any one of claims 6 to 8, characterized in that: