JP2019131248A - Multiple-bottle made of polyester resin and its manufacturing method - Google Patents

Abstract

To provide a multiple-bottle made of polyester resin of which the inner container body is easy to be removed from the outer shell bottle and which is easy to be volume reduction deformed.SOLUTION: A multiple-bottle made of polyester resin 1 comprises: an inner container body 3 which has an outer shell bottle 2 having an outer mouth part 4 and an outer shell bottle body 21, a cylindrical inner mouth part 13 provided in the outer mouth part 4 of the outer shell bottle 2, an inner container body 14 connected to the inner mouth part 13 and conforming to the inner shape of the outer shell bottle 2 and is deformed by external pressure; an air path 19 which is formed between the outer mouth part 4 and the inner mouth part 13 and introduces outside air between the outer shell bottle 2 and the inner container body 3; the outer shell bottle body 21 has a shoulder part 5, a body part 6 and a bottom part 7. The inner container body 14 is formed to be thinner than the outer shell bottle body, and an unevenly engraved concave and convex pattern 26 is provided in the part of the inner container body 14 corresponding to the shoulder 5.SELECTED DRAWING: Figure 2

Description

  TECHNICAL FIELD The present invention relates to a polyester resin multiple bottle including an inner container body disposed in an outer shell bottle and a method for manufacturing the same.

  Conventionally, an inner container body that is deformed by volume reduction due to external pressure (hereinafter sometimes referred to as “volumetric deformation”) is disposed inside an outer shell bottle that can be restored to its original shape against external pressure, Synthetic resin multiple bottles are known in which outside air is introduced between the inner container body (see, for example, Patent Documents 1 and 2).

  When the plastic multi-bottle is pressed against the body part of the outer shell bottle, the inner container body is reduced in volume and the contents contained in the inner container body are poured out, while the pressure is released. Outside air is introduced between the outer shell bottle and the inner container body by the action of a check valve provided separately. As a result, the outer shell bottle is restored to its original shape by the external air pressure, while the inner container body is maintained in the volume-reduced deformation state. When doing so, since the outside air does not enter the inner container body, the contents stored in the inner container body can be prevented from being altered by oxidation or the like.

JP2013-245010A JP 2010-082916 A

  Conventionally, multiple bottles made of soft polyethylene resin, which can be easily reduced in volume, have been put to practical use as a multiple bottle. Polyester resins (for example, polyethylene terephthalate resin) are more transparent in container or content than polyethylene resin. It is conceivable that the multiple bottles may be molded from a polyester resin instead of a polyethylene resin.

  However, when the multiple bottle is molded of polyester resin, there is a problem that the inner container body sticks to the inner surface of the outer shell bottle and it is difficult for air to enter between the outer shell bottle and the inner container body. Further, since the polyester resin is inferior in flexibility as compared with the polyethylene resin, there is a problem that the inner container body is hardly deformed by volume reduction.

  In view of the above points, an object of the present invention is to provide a multi-bottle made of polyester resin fats and a method for producing the same, in which the inner container body is easily peeled off from the outer shell bottle and is easily reduced in volume.

[1] In order to achieve the above object, the present invention provides:
A cylindrical outer mouth portion, and an outer shell bottle main body connected to the outer mouth portion, and an outer shell bottle made of a polyester resin capable of returning to its original shape against an external pressure;
A cylindrical inner mouth portion disposed in the outer mouth portion of the outer shell bottle, and an inner container body body connected to the inner mouth portion and conforming to the inner surface shape of the outer shell bottle, An inner container body made of polyester resin deformed by external pressure;
An air passage formed between the outer mouth portion and the inner mouth portion for introducing outside air between the outer shell bottle and the inner container body,
The outer shell bottle body includes a shoulder connected to the outer opening, a trunk connected to the shoulder, and a bottom connected to the trunk.
The outer shell bottle and the inner container body are polyester resin multiple bottles formed simultaneously by blow molding,
The inner container body is thinner than the outer bottle body,
An uneven pattern is provided on the shoulder and the portion of the inner container body corresponding to the shoulder.

  According to the present invention, since the inner container body is thinner than the thickness of the outer bottle body, and the unevenness pattern is formed on the shoulder portion of the outer bottle and the inner container body, the polyester resin (for example, polyethylene Even if the outer shell bottle and inner container body are manufactured with terephthalate resin, etc., the air sucked from the air passage can easily enter between the shoulder of the outer shell bottle and the inner container body, and the contents from the outer bottle The container body can be easily separated, and the volume reduction deformation of the inner container body is facilitated.

  [2] In the present invention, the concavo-convex pattern may be a wrinkle pattern such as the surface of a leather product. By applying a wrinkle pattern as the concavo-convex pattern, the appearance of the polyester resin multiple bottle can be improved. In addition, as the concavo-convex pattern, various patterns such as satin, wood grain, fabric, and lattice can be used. By selecting a pattern such as a wrinkle pattern, a pear texture, a wood grain, a fabric, or a lattice as the uneven pattern, it is possible to improve the appearance of the outer shell bottle when an uneven pattern is also provided on the shoulder.

  [3] In the present invention, it is preferable that the outer shell bottle and the inner container body are made of polyethylene terephthalate resin. According to this configuration, even when the outer shell bottle and the inner container body are manufactured from a relatively hard material such as polyethylene terephthalate resin, the inner container body main body can be easily peeled from the outer shell bottle.

  [4] In the present invention, it is preferable to interpose a release agent between the outer shell bottle and the inner container body. According to such a configuration, the inner container body can be more easily separated from the outer shell bottle. As the mold release agent, for example, liquid paraffin or silicon compound can be used.

[5] A method for producing a polyester resin multiple bottle of the present invention includes:
A cylindrical outer mouth portion, and an outer shell bottle main body connected to the outer mouth portion, and an outer shell bottle made of a polyester resin capable of returning to its original shape against an external pressure;
A cylindrical inner mouth portion disposed in the outer mouth portion of the outer shell bottle, and a shape that is connected to the inner mouth portion and conforms to the inner surface shape of the outer shell bottle, and is thinner than the outer shell bottle main body. An inner container body, and an inner container body made of polyester resin that is deformed by external pressure;
An air passage formed between the outer mouth portion and the inner mouth portion for introducing outside air between the outer shell bottle and the inner container body,
The outer shell bottle body includes a shoulder connected to the outer opening, a trunk connected to the shoulder, and a bottom connected to the trunk.
The outer shell bottle and the inner container body are a method for producing a polyester resin multiple bottle that is simultaneously molded by blow molding,
The bottomed cylindrical inner preform that is thinner than the outer preform and is the source of the inner container body in the bottomed cylindrical outer preform that is the source of the outer shell bottle when blow molding is performed In a state where the bottom of the inner preform is pressed with a rod while the rod is inserted, the mold for the outer shell bottle has a concavo-convex pattern on the portion corresponding to the shoulder. The outer shell bottle and the inner container body are formed at the same time by molding.

  According to the present invention, it is possible to simultaneously form the concavo-convex pattern on the shoulder and the concavo-convex pattern on the inner container body by simultaneously blow-molding the outer shell bottle and the inner container body. The bottle can be manufactured easily. Also, by making the inner preform thinner than the outer preform, the inner container body formed by blow molding is also thinner than the outer bottle body, and an uneven pattern is provided on the shoulder and the inner container body. Thereby, an inner container main body can be easily peeled from a shoulder part. This is because there is a difference in internal stress between the outer shell bottle body after blow molding and the inner container body body, and the inner container body body is easy to peel off from the shoulder portion of the outer shell bottle. It is considered that the shoulder portion and the portion of the inner container body corresponding to the shoulder portion increase the surface area due to the uneven pattern and increase the influence of the difference in internal stress.

The perspective view which shows embodiment of the multiple bottle made from the polyester resin of this invention. Explanatory drawing which shows the cross section cut | disconnected by the II-II line | wire of FIG.

  As shown in FIGS. 1 and 2, the polyester resin multiplex bottle 1 of the present embodiment includes an outer shell bottle 2 that can be restored to its original shape with respect to the external pressure, and a content that is accommodated inside the outer shell bottle 2 and is deformed by the external pressure. It consists of the body 3.

  The outer bottle 2 is made of, for example, polyethylene terephthalate resin, and includes a cylindrical outer opening 4 and an outer bottle main body 21 connected to the outer opening 4. The outer bottle body 21 includes a shoulder portion 5, a cylindrical body portion 6 connected to the shoulder portion 5, and a bottom portion 7 connected to the cylindrical body portion 6. The bottom portion 7 includes a grounding portion 7b that is grounded at the lower end, and a concave portion 8 that bulges inside the outer shell bottle 2 on the inner peripheral side of the grounding portion 7b and imparts self-supporting property to the polyester resin multiple bottle 1. Yes.

  The outer opening 4 includes a male screw portion 10 and a support ring 11 on the outer peripheral surface. The shoulder 5 has a quadrangular pyramidal portion in contact with the outer opening 4. The shoulder portion 5 below the quadrangular pyramid portion gradually increases in diameter from the quadrangular pyramid portion toward the cylindrical trunk portion 6, and the corners of the quadrangular pyramid become smooth and are continuous with the cylindrical trunk portion 6.

  The bottom portion 7 has a quadrangular pyramid portion in contact with the ground contact portion 9, and the diameter of the quadrangular pyramid gradually increases from the quadrangular pyramid portion toward the cylindrical body 6 above the quadrangular pyramid portion. It is smooth and continues to the cylindrical body 6. Moreover, the recessed part 8 is provided with the quadrangular frustum-shaped recessed part 8a, 8b, 8c laminated | stacked on 3 steps | paragraphs.

  Further, the quadrangular pyramid portions of the shoulder portion 5 and the bottom portion 7 each have a quadrangular horizontal cross section perpendicular to the vertical axis, and an apex is provided with an R, and the apex is provided with a ridge line. Here, the ridge line of the bottom 7 is continuous with the extension of the ridge line of the shoulder 5.

  On the other hand, the inner container body 3 is made of, for example, polyethylene terephthalate resin, and is connected to the cylindrical inner mouth portion 13 disposed on the inner peripheral side of the outer mouth portion 4 and the inner mouth portion 13. The inner container body 14 having a shape along the shape of the inner surface of the shoulder 5, the cylindrical body 6, the bottom 7, the grounding portion 7 b, and the recess 8. The inner container body 14 is formed to be thinner than the outer bottle body 21. The inner mouth part 13 includes an extension part 15 that extends upward from the upper end of the outer mouth part 4 and a flange part 16 that projects radially outward from the extension part 15. The part 16 is locked to the upper edge of the outer opening 4.

  The polyester resin used for the outer bottle 2 and the inner container body 3 is preferably polyethylene terephthalate resin, but is not limited thereto, and may be, for example, polybutylene terephthalate resin or polyethylene naphthalate resin. Alternatively, known polyester resins may be used alone or in combination.

  Moreover, the inner port part 13 is provided with a plurality of vertical grooves 17 on the outer peripheral surface at intervals in the circumferential direction. The vertical groove 17 is connected to a horizontal groove 18 formed on the lower surface of the flange portion 16, and the horizontal groove 18 is opened to the outside at the outer peripheral edge of the flange portion 16. As a result, the vertical groove 17 and the horizontal groove 18 form an air passage 19 for introducing outside air between the outer shell bottle 2 and the inner container body 3. Each vertical groove 17 extends to the lower end of the inner opening 13.

  The shoulder portion 5 is formed so as to gradually become thinner while expanding in diameter downward from the lower end of the outer opening portion 4. The shoulder portion 5 is provided with a wrinkle pattern 25 that is recessed in a rugged shape like a wrinkle on the surface of the leather product over the entire circumference. In addition, in this embodiment, although the wrinkle pattern 25 which was dented like a wrinkle of the surface of a leather product was demonstrated as a concavo-convex pattern, the concavo-convex pattern of the present invention is not limited to the unevenness such as a wrinkle on the surface of a leather product, For example, it may be other textured pattern (texture pattern) such as satin, wood grain, fabric, lattice.

  As shown in the cross-sectional view of FIG. 2, a wrinkle pattern 26 similar to that of the shoulder portion 5 is provided in the portion of the inner container body 14 corresponding to the shoulder portion 5.

  The multiple bottle 1 made of polyester resin according to this embodiment is used with a cap with a check valve (not shown) attached to the outer opening 4 of the outer shell bottle 2, and the contents not shown are accommodated in the inner container body 3. When the contents are poured out, the outer opening 4 and the inner opening 13 are inclined downward. And if the cylindrical trunk | drum 6 of the outer shell bottle 2 is hold | gripped and pressed, the content will be poured out because the inner container main body 14 carries out volume reduction deformation. In the multiple bottle 1 made of polyester resin, the cylindrical body 6 has a circular cross section orthogonal to the axis, and can be pressed from any direction against the axis, so the center of the cylindrical body 6 can be easily grasped. Thus, the volume of the inner container body 18 can be reduced and deformed, and an excellent squeeze property can be obtained.

  Next, when the pressing of the cylindrical body 6 of the outer shell bottle 2 is released, uneven patterns 25 and 26 are formed from the vertical grooves 17 of the air passage 19 between the outer shell bottle 2 and the inner container body 14. Outside air is introduced between the shoulder 5 and the inner container body 14, and the outer bottle 2 returns to its original shape by its own restoring force. However, outside air does not enter the inner container body 14, and the inner container The body main body 14 is maintained in a state of being deformed and reduced in volume.

  At this time, since the contents are concentrated in the direction of the inner mouth portion 13 due to gravity, the inner container body 14 is sandwiched between the ridgelines of the bottom portion 7 in the portion corresponding to the quadrangular pyramid portion of the bottom portion 7 of the outer shell bottle 2. A valley fold portion to the inner side of the inner container body 14 is formed in the side surface portion corresponding to the portion to be bent, and the valley fold deformation is started by immersing in the inner side portion.

  In the multiple bottle 1 made of polyester resin, the content gradually decreases by repeatedly pressing and releasing the cylindrical body 6 of the outer shell bottle 2. When the content is reduced, the inner container body 14 is deformed in the valley from the outside of the inner container body 14 in the width direction starting from the portion corresponding to the quadrangular pyramidal portion of the bottom 7 of the outer shell bottle 2. Proceeds toward you and folds.

  In the present embodiment, the wrinkle patterns 25 and 26 are present in the shoulder 5 and the inner container body 14, so that outside air is introduced between the wrinkle patterns 25 and 26 during use after filling the contents. When the external pressure is applied, the portion of the inner container body 14 corresponding to the shoulder portion 5 is peeled off from the outer shell bottle 2 earlier, and the folded portion becomes a trough portion and the volume reduction deformation is performed. As a result, the contents stored in the inner container body 14 can be poured out without any excess, and the amount of remaining liquid can be reduced.

  In addition, the multiple bottle 1 made of polyester resin according to the present embodiment includes the concave portion 8 formed of the quadrangular frustum-shaped concave portions 8a, 8b, and 8c, so that the inner container body is formed in the concave portion 8 by thermocompression bonding during blow molding. The main body 18 is in close contact with the outer shell bottle 2. Further, the concave portion 8 is formed of quadrangular pyramid-shaped concave portions 8a, 8b, and 8c, and includes a large number of step portions and bent portions, so that the concave portion 8 has a space between the outer shell bottle 2 and the inner container body 14. The outside air will not invade.

  Therefore, the inner container body 14 does not peel from the outer shell bottle 2 in the recess 8 while the valley fold is formed along the length direction of the outer shell bottle 2, and is accommodated in the inner container body 14. Therefore, it is possible to more reliably pour out the contents that have been removed, and to reduce the amount of the remaining liquid.

  The multiple bottle 1 made of polyester resin in which a wrinkle pattern 25 is formed on the shoulder portion 5 of the present embodiment has a bottomed cylindrical outer preform for the outer shell bottle 2 made of polyethylene terephthalate resin and a barrel portion that is more than the outer preform. The inner preform is inserted into the outer preform using the bottomed cylindrical inner preform for the thin inner container body 3, and a release agent (preferably liquid paraffin) is provided between the body portions of both preforms. Using a blow molding die designed so that a wrinkle pattern 25 is formed on the shoulder portion 5 of the outer shell bottle 2 and the portion of the inner container body 14 corresponding to the shoulder portion 5. Both preforms can be placed inside and blow molded at the same time. The inner container body 14 after the blow molding is also thinner than the outer shell bottle 2.

  The wrinkle pattern of the blow mold is formed by machining or the like. In the multiplex bottle 1 obtained by laminating the outer preform and the inner preform and simultaneously performing stretch blow molding, not only the wrinkle pattern 25 of the shoulder 5 but also the inner container body 14 corresponding to the shoulder 5 is formed. A wrinkle pattern 26 is simultaneously formed on the portion. The wrinkle pattern on the shoulder of the blow mold is set so that the wrinkle pattern 25 on the shoulder 5 and the wrinkle pattern 26 on the inner container body 14 are formed simultaneously.

  An air passage 19 is provided between the outer opening 4 and the inner opening 13 of the thus manufactured multiple bottle, and a wrinkle pattern 25 is formed on the shoulder 5 to correspond to the shoulder 5. A similar wrinkle pattern 26 is also formed on the inner container body 14. The outer shell bottle 2 and the inner container body 14 are taken out of the blow mold and cooled after blow molding. The wrinkle pattern 25 on the shoulder 5 and the wrinkle pattern 26 on the inner container body 14 cause a difference in internal stress due to a difference in cooling temperature between the inner side and the outer side and a difference in thickness. 5 and the wrinkle pattern 26 of the inner container body 14 can be easily separated with a slight external force, for example, by introducing outside air. In particular, the peelability is improved by the wrinkle patterns 25 and 26 between the shoulder portion 5 where the wrinkle patterns 25 and 26 are formed and the inner container body 14. This is presumably because the surface area is increased by the amount of the wrinkle patterns 25 and 26, so that the difference in internal stress in the wrinkle patterns 25 and 26 is also remarkable as compared with other portions.

  According to the multiple bottle 1 made of polyester resin of the present embodiment, since the wrinkle patterns 25 and 26 are provided on the inner surface of the shoulder portion 5 of the outer shell bottle 2 and the outer surface of the inner container body 14, a relatively hard material. Even when the outer shell bottle and the inner container body are manufactured with polyethylene terephthalate resin or the like, the air taken in from the air passage 19 is between the shoulder portion 5 where the wrinkle patterns 25 and 26 are formed and the inner container body main body 14. By entering, the inner container body 14 can be easily separated from the outer shell bottle 2.

  In addition, in the polyester resin multiplex bottle in which the outer shell bottle and the inner container body are formed of polyester resin, both the outer shell bottle and the inner container body are made of polyester resin, and the contents filled in the inner container body are hot. When the outer shell bottle and the inner container body are in close contact, such as when hot-packed in a heated state or when the label is heated and shrunk to attach a shrink label to the outer surface of the outer shell bottle after filling the contents When the multiple bottle made of polyester resin is heated, there is a possibility that the shoulder of the outer shell bottle and the inner container body are difficult to peel off. In particular, when the part that is difficult to separate is the shoulder and the part of the inner container body corresponding to the shoulder, it is close to the air passage into which the outside air is introduced, and thus adversely affects the volume reduction deformation of the inner container body. There is a fear.

  However, in the multiple bottle 1 made of polyester resin according to the present embodiment, the wrinkle pattern 25 of the shoulder portion 5 and the inner container body 14 of the inner container body 14 are filled even when the high temperature contents are filled or when the shrink label is heated. Since the peelability between the wrinkle pattern 26 is improved, the inner container body 14 is easily peeled from the shoulder 5 by introducing outside air from the air passage 19, and the outer shell bottle 2 and the inner container body 14. The outside air can be easily sent to the lower part between.

  In addition, after the manufacture of the polyester resin multiple bottle 1 for quality confirmation whether the inner container body 14 of the polyester resin multiple bottle 1 is free of pinholes or the like, the contents from the portion of the outer shell bottle 2 except for the recess 8 once. The body body 14 may be peeled off to check the quality such as the presence or absence of pinholes. And after the quality check, also in the polyester resin multiple bottle 1 in which the inner container body 14 is inflated and returned to its original state, for example, a heating content filling step or a heat treatment step for attaching a shrink label In the subsequent steps such as the above, according to the multiple bottle 1 made of polyester resin of the present embodiment, the inner container body 14 sticks to the shoulder 5 of the outer shell bottle 2 due to the wrinkle patterns 25 and 26 and is difficult to peel off. This can be prevented.

  In the present embodiment, the outer bottle 2 and the inner container body 14 are simultaneously blow-molded to simultaneously form the wrinkle pattern 25 of the shoulder 5 and the wrinkle pattern 26 of the inner container body 14. Therefore, it is easy to manufacture the multiple bottle 1 made of polyester resin.

  In the present embodiment, a release agent is interposed between the outer shell bottle 2 and the inner container body 14. Thereby, the inner container body 14 can be further easily separated from the outer shell bottle 2. As the mold release agent, for example, liquid paraffin or silicon compound can be used.

  In this embodiment, the portion connected to the outer opening 4 of the shoulder 5 in the outer shell bottle 2 is a quadrangular pyramid, but the entire shoulder 5 may be a quadrangular pyramid. Moreover, in this embodiment, although the part connected to the earthing | grounding part 7b of the bottom part 7 in the outer shell bottle 2 is made into the quadrangular pyramid part, it is good also considering the bottom part 7 whole as a quadrangular pyramid part. Alternatively, one or both of the shoulder and the bottom may be formed in a conical shape.

  In the present embodiment, the quadrangular pyramid portion of the outer shell bottle 2 has a quadrangular pyramid shape whose horizontal cross section perpendicular to the vertical axis is quadrangular, but the quadrangular pyramid portion is a triangular shape whose horizontal cross section is triangular. Any one of a pyramid shape, a pentagonal pyramid shape, and a hexagonal pyramid shape that is a hexagonal shape may be used. In addition, the polygonal pyramid may be cut at the vertex of the polygon, or may have R attached to the vertex of the polygon, and may further bulge the sides sandwiched between the vertices outward, One or more vertices may be provided on the bulged side.

  Moreover, in this embodiment, although it is set as the structure provided with the external thread part 10 in the outer peripheral surface of the outer opening part 4, the outer opening part 4 may be a mere cylindrical shape which is not provided with the external thread part 10, and does in this way. For example, it can be applied to a plug-type mouth portion such as a soy sauce bottle.

  Further, in the present embodiment, the case where the wrinkle pattern 25 is provided only on the shoulder portion 5 has been described in consideration of the influence on the squeeze property of the cylindrical body portion 6. However, the uneven pattern of the shoulder portion of the present invention is not limited to this, and the uneven pattern may be provided only on the upper half of the shoulder portion. Moreover, you may give an uneven | corrugated pattern to a trunk | drum or a bottom part.

DESCRIPTION OF SYMBOLS 1 Polyester resin multiple bottle 2 Outer shell bottle 3 Inner container body 4 Outer mouth part 5 Shoulder part 6 Body part 7 Bottom part 7b Grounding part 8 Recessed part 10 Male thread part 11 Support ring 13 Inner mouth part 14 Inner container body 15 Extension part 16 Wrinkle 17 Vertical groove 18 Horizontal groove 19 Ventilation path 21 Outer shell bottle body 25 Wrinkle pattern on shoulder 26 Wrinkle pattern on inner container body

Claims (5)

A cylindrical outer mouth portion, and an outer shell bottle main body connected to the outer mouth portion, and an outer shell bottle made of a polyester resin capable of returning to its original shape against an external pressure;
A cylindrical inner mouth portion disposed in the outer mouth portion of the outer shell bottle, and an inner container body body connected to the inner mouth portion and conforming to the inner surface shape of the outer shell bottle, An inner container body made of polyester resin deformed by external pressure;
An air passage formed between the outer mouth portion and the inner mouth portion for introducing outside air between the outer shell bottle and the inner container body,
The outer shell bottle body includes a shoulder connected to the outer opening, a trunk connected to the shoulder, and a bottom connected to the trunk.
The outer shell bottle and the inner container body are polyester resin multiple bottles that are simultaneously molded by blow molding,
The inner container body is formed thinner than the outer bottle body,
A multiple bottle made of polyester resin, wherein the shoulder portion and the portion of the inner container body corresponding to the shoulder portion are provided with an uneven pattern. The multiple bottle made of polyester resin according to claim 1,
The multi-bottle made of polyester resin, wherein the uneven pattern is a wrinkle pattern. A multiple bottle made of polyester resin according to claim 1 or claim 2,
The outer bottle and the inner container body are made of polyethylene terephthalate resin. A multiple bottle made of polyester resin according to any one of claims 1 to 3,
A polyester resin multiple bottle, wherein a release agent is interposed between the outer shell bottle and the inner container body. It has a cylindrical outer opening, a shoulder connected to the outer opening, a trunk connected to the shoulder, and a bottom connected to the shoulder, and can be restored to its original form with respect to external pressure. An outer bottle made of polyester resin;
A cylindrical inner mouth portion disposed in the outer mouth portion of the outer shell bottle, and an inner container body body connected to the inner mouth portion and conforming to the inner surface shape of the outer shell bottle, An inner container body made of polyester resin deformed by external pressure;
An air passage formed between the outer mouth portion and the inner mouth portion for introducing outside air between the outer shell bottle and the inner container body;
A method for producing a multiple bottle made of polyester resin comprising:
The bottomed cylindrical inner preform that is thinner than the outer preform and is the source of the inner container body in the bottomed cylindrical outer preform that is the source of the outer shell bottle when blow molding is performed In a state where the bottom of the inner preform is pressed with a rod while the rod is inserted, the mold for the outer shell bottle has a concavo-convex pattern on the portion corresponding to the shoulder. A method for producing a synthetic resin blow-molded multiple bottle, wherein the outer shell bottle and the inner container body are simultaneously formed by molding.