JP2020189653A - Multiple container - Google Patents

Abstract

To provide a container capable of achieving both regular shrinkage of a container and securing of moldability.SOLUTION: A multiple container 1 is a bottle-shaped container in which an inner container 20 and an outer container 10 for containing the inner container 20 are laminated in a peelable manner. In a cross section of a trunk part 5 of the outer container 10 and the inner container 20, the shape of the outer container 10 and the inner container 20 is an irregular shape different from a circle, and thickness ratio of the inner container 20 with respect to the thickness of the outer container 10 becomes minimum at a longest part 15 in which a distance from a central axis Z is the longest and becomes maximum at a shortest part 16 in which a distance from the central axis Z is the shortest.SELECTED DRAWING: Figure 2

Description

The present invention relates to multiple containers.

As a container for containing contents such as liquid seasonings or liquid cosmetics and maintaining the freshness thereof, a multi-layer container called a derami bottle, an airless bottle, a laminated peeling container or the like is known (for example, Patent Document 1).

In Patent Document 1, the annular claw portion protruding from the protruding portion protruding outward from the bottom of the inner container is locked in the through hole at the bottom of the outer container to suppress the lifting of the bottom of the inner container. Multiple containers are described that regulate the contraction mode of the vessel. Further, in Patent Document 1, a through hole is provided in the preform for the outer container, and a protruding portion and an annular claw portion are provided in the preform for the inner container, and these preforms are biaxially stretched and blow molded. It is described that the multiple containers are manufactured.

Japanese Unexamined Patent Publication No. 2014-69875

The multiple container described in Patent Document 1 can suppress the lifting of the bottom portion of the inner container, but there is a possibility that the body portion occupying most of the inner container contracts irregularly. In order to prevent the inner container described in Patent Document 1 from contracting irregularly, it is conceivable to thin the inner container so that the inner container is easily deformed. However, in order to make the inner container thinner, it is necessary to make the preform for the inner container also thinner, which may make it difficult to ensure moldability. Moreover, the preform described in Patent Document 1 must be molded into a complicated shape such as the above-mentioned protruding portion and annular claw portion, and the difficulty of molding is high, so that molding defects may easily occur. There is.

The present invention has been made in view of the above circumstances, and it is an example of a problem to solve the above-mentioned problems. That is, one example of the subject of the present invention is to provide a container capable of achieving both regular shrinkage of the container and ensuring moldability.

The present invention is a bottle-shaped multiple container in which an inner container and an outer container containing the inner container are detachably laminated, and the outer container is a cross section of the outer container and the body of the inner container. The shape of the inner container is different from the circular shape, and the ratio of the thickness of the inner container to the thickness of the outer container is the longest portion where the distance from the central axis of the outer container is the longest. It becomes the minimum, and becomes the maximum at the shortest portion where the distance from the central axis of the outer container is the shortest.

Preferably, the body portion of the inner container is provided with thin-walled portions extending in the axial direction at a plurality of locations at intervals in the circumferential direction, and the thickness of the body portion of the inner container is preferably provided in the cross section. The thickness is the maximum at the portion of the outer container facing the shortest portion, and the minimum thickness at the thin portion provided at the portion of the outer container facing the longest portion.

Preferably, the minimum thickness is 70% or less of the maximum thickness.

Preferably, the inner container shrinks as the contents decrease, and the thin-walled portion bends so that the inner surfaces of the non-thin-walled portions in the body portion of the inner container come close to each other, whereby the inner container is bent. Regulate the contraction mode of.

Preferably, the outer container and the inner container are formed by stacking an inner preform which is a preform corresponding to the inner container and an outer preform which is a preform corresponding to the outer container. It is manufactured by biaxial stretching blow molding at the same time.

According to the present invention, it is possible to provide a container capable of achieving both regular shrinkage of the container and ensuring moldability.

It is a figure which shows typically the vertical cross section of the multi-layer container which concerns on Embodiment 1. FIG. FIG. 5 is a diagram schematically showing a cross section of a multi-layer container cut in a plane containing the line II-II shown in FIG. 1. It is a figure for demonstrating the contraction mode of the inner container shown in FIG. It is a figure which shows typically the vertical cross section of the preform for manufacturing the multiple container shown in FIG. 1. It is a figure which shows typically the cross section of the preform cut in the plane including the VV line shown in FIG. It is a figure for demonstrating the multiple container which concerns on Embodiment 2. FIG. The figure for demonstrating the preform for manufacturing the multiplex container shown in FIG. 6 is shown.

The present invention is widely applicable to a container manufactured by biaxially stretching blow molding a preform made of a thermoplastic resin, and a preform for manufacturing the container. In the present embodiment, a case where the present invention is applied to a container having a multiple structure and a preform thereof will be described as an example.

Hereinafter, embodiments of the present invention will be described with reference to the drawings. The embodiments described below show some examples of the present invention and do not limit the contents of the present invention. Moreover, not all of the configurations and operations described in the embodiments are essential as the configurations and operations of the present invention.

In the present embodiment, the direction along the central axis Z of the multiple container 1 having a bottle shape is also referred to as "axial direction", and the direction orthogonal to the central axis Z of the multiple container 1 is also referred to as "diameter direction". The direction of orbiting with respect to the central axis Z on the plane orthogonal to the central axis Z of the above is also referred to as "circumferential direction". Further, in the present embodiment, the axial direction from the mouth 3 to the bottom 6 of the multiple container 1 is also referred to as "downward", and the axial direction from the bottom 6 to the mouth 3 of the multiple container 1 is also referred to as "upward". Further, in the present embodiment, a cross section obtained by cutting the multiple container 1 along a plane along the central axis Z of the multiple container 1 is also referred to as a “vertical cross section”, and the multiple container 1 is provided on a plane orthogonal to the central axis Z of the multiple container 1. The cut section is also referred to as a "cross section". The cross section is also referred to as a "flat section". The same applies to the preforms 100 and 200.

[Embodiment 1: Configuration of multiple containers]
FIG. 1 is a diagram schematically showing a vertical cross section of the multiple container 1 according to the first embodiment. FIG. 2 is a diagram schematically showing a cross section of the multilayer container 1 cut in a plane including the line II-II shown in FIG. FIG. 3 is a diagram for explaining a contraction mode of the inner container 20 shown in FIG. The alternate long and short dash line in FIG. 1 indicates a state in which the inner surface of the outer container 10 and the outer surface of the inner container 20 are peeled off and the inner container 20 is contracted.

The multiple container 1 is a container having a bottle shape. The multiple container 1 is a freshness-preserving bottle that contains contents such as liquid seasonings, liquid cosmetics, and beverages, and retains the freshness thereof.

The multilayer container 1 is a bottle made of a thermoplastic resin and is manufactured by blow molding. Preferably, the multiple container 1 is manufactured by biaxially stretching blow molding a preform formed into a bottomed tubular shape such as a test tube shape by injection molding or the like. Examples of the resin used for molding the multilayer container 1 include a polyolefin resin, an ethylene-vinyl copolymer, a styrene resin, a vinyl resin, a polyamide resin, a polyester resin, a polycarbonate resin, and a polyphenylene oxide resin. Alternatively, a biodegradable resin or the like can be mentioned. Preferably, examples of the resin used for molding the multiple container 1 include a polyolefin-based resin and a polyester-based resin. More preferably, a polyester-based resin can be mentioned as a resin used for molding the multiple container 1. Examples of the polyester-based resin include resins such as polyethylene terephthalate, polybutylene terephthalate, polyethylene naphthalate, polyethylene furanoate, and copolymerized polyesters thereof. Particularly preferably, the resin used for molding the multiple container 1 is a polyethylene terephthalate resin.

As shown in FIG. 1, the multiple container 1 includes a mouth portion 3 which is one end of the multiple container 1 and has a spout 21 for contents, and a bottom 6 which is the other end of the multiple container 1 and has a grounding portion. To be equipped with. Further, the multiple container 1 includes a shoulder portion 4 extending downward from the mouth portion 3 while expanding outward in the radial direction, and a body portion 5 extending downward from the shoulder portion 4 and connecting to the bottom portion 6.

The multi-container 1 includes a bottle-shaped outer container 10 that constitutes the outer shell of the multi-container 1 and contains the inner container 20, an inner container 20 that houses the contents and has a shape along the inner surface of the outer container 10. An outside air introduction hole 11 capable of introducing outside air is provided between the outer container 10 and the inner container 20. The multilayer container 1 has a multilayer structure in which the inner surface of the outer container 10 and the outer surface of the inner container 20 are laminated so as to be peelable.

The outer container 10 is formed so that the bottom portion 6 is grounded and can stand on its own. The shoulder portion 4 and the body portion 5 of the outer container 10 are formed so as to bend and deform inward when pressed by a squeeze operation, and to be restored to the original shape before pressing when the pressing is released.

The inner container 20 has a storage space S for accommodating the contents and a spout 21, and is formed to be contractable as the contents decrease. The shoulder portion 4 and the body portion 5 of the inner container 20 are formed to have a wall thickness thinner than that of the outer container 10 so as to shrink as the contents decrease. The inner container 20 may be molded containing an oxygen absorber in order to secure a gas barrier property for the contents.

As shown in FIG. 1, the outside air introduction hole 11 is provided in the mouth portion 3 of the outer container 10 and communicates with the void A. The void A is formed between the shoulder portion 4 to the bottom portion 6 of the outer container 10 and the shoulder portion 4 to the bottom portion 6 of the inner container 20 by peeling off the inner surface of the outer container 10 and the outer surface of the inner container 20. It is a space. The outside air introduction hole 11 may be provided as a slit in a portion where the mouth portion 3 of the outer container 10 and the mouth portion 3 of the inner container 20 are fixed.

A cap with a check valve is attached to the mouth portion 3 of the multiple container 1. In the multiple container 1, when the outer container 10 is pressed by a squeeze operation, the contents are poured out and the inner container 20 contracts. When the pressing of the outer container 10 is released, the outer container 10 is restored to its original shape before being pressed, while the contracted state of the inner container 20 is caused by the introduction of the outside air from the outside air introduction hole 11 into the void A and the action of the check valve. Be maintained. As a result, in the multiple container 1, the inner container 20 shrinks as the contents decrease, and the inflow of outside air from the spout 21 is suppressed, so that the oxidation of the contents is suppressed and the freshness is maintained. be able to.

In the multiple container, the inner container shrinks as the contents decrease, but if the inner container shrinks irregularly, the flow path of the contents from the accommodation space to the spout is not secured, and the contents are poured out. It may be hindered. As a result, in the multiple container, there is a possibility that the contents cannot be completely poured out and remain in the final stage of use when the capacity of the contents is reduced.

Therefore, as shown in FIG. 2, the multiple container 1 is provided with a thin-walled portion 22 for regulating the contraction mode of the inner container 20 so that the inner container 20 contracts regularly. The thin-walled portion 22 is provided on the body portion 5 of the inner container 20, and the wall thickness thereof is thinner than that of the non-thin-walled portion 23. The non-thin portion 23 is another portion of the body portion 5 of the inner container 20 where the thin portion 22 is not provided.

The thin-walled portion 22 is provided so as to have a width in the circumferential direction and extend in the axial direction. Specifically, the thin-walled portion 22 is formed in the body portion 5 of the inner container 20 in a band shape having a width in the circumferential direction and extending along the axial direction. The thin-walled portions 22 are provided at a plurality of locations at intervals in the circumferential direction. That is, the thin-walled portion 22 and the non-thin-walled portion 23 are alternately arranged in the circumferential direction. It is preferable that the plurality of thin-walled portions 22 are provided so that the distances to their respective central axes Z are substantially the same. It is preferable that the plurality of thin-walled portions 22 are provided so as to be point-symmetrical with the central axis Z as the center of symmetry in the cross section of the body portion 5 of the inner container 20.

Since the thin portion 22 is thinner than the non-thin portion 23, it is more easily bent than the non-thin portion 23. Therefore, when the inner container 20 contracts, when a force that deforms the inner container 20 inward in the radial direction is applied to the outer surface of the inner container 20, the thin portion 22 is deformed and bent before the non-thin portion 23. .. At this time, the thin-walled portion 22 is bent so that the inner surfaces of the two non-thin-walled portions 23 adjacent to the thin-walled portion 22 are brought close to each other in the circumferential direction, and becomes the ridgeline of the contracted inner container 20. After that, as shown in FIG. 3, as the shrinkage of the inner container 20 progresses, the thin-walled portion 22 extends in the axial direction and acts like a support column for supporting the circumferential end of the non-thin-walled portion 23, and the non-thin-walled portion 22 acts like a support column. 23 is deformed so as to bend inward in the radial direction. In this way, the thin-walled portion 22 becomes the starting point of contraction deformation of the inner container 20 due to the difference in wall thickness from the non-thin-walled portion 23, and the inner container 20 is regularly contracted. Therefore, the contraction mode of the inner container 20 is regulated. can do.

The thin-walled portion 22 is formed in a concave shape in which the inner surface of the body portion 5 of the inner container 20 is recessed outward in the radial direction. As a means for providing a wall thickness difference in the body portion 5 of the inner container 20, it is also conceivable to provide a convex thick wall portion having an inner surface protruding inward in the radial direction with respect to the body portion 5 of the inner container 20. Be done. However, since the thick portion is a portion that is hard to be deformed because the wall thickness is thicker than the others, the inner container 20 is from the non-thick portion that occupies most of the body portion 5 that is not provided with the thick portion. It contracts irregularly first. Therefore, the thick portion is difficult to function as a means for regulating the contraction mode of the inner container 20.

For this reason, in the multiple container 1, the thin-walled portion 22 is formed in a concave shape in which the inner surface of the body portion 5 of the inner container 20 is recessed outward in the radial direction.

Further, the preform 200 corresponding to the inner container 20 is generally compared with the preform 100 corresponding to the outer container 10 and the preform of a general PET bottle for beverages so that the inner container 20 can be easily contracted. It is necessary to reduce the wall thickness. Therefore, the ratio of the axial length to the wall thickness of the preforms 200 is larger than that of these preforms. As a result, it is difficult for the preform 200 to properly fill the mold with the molten resin at the time of injection molding as compared with these preforms, and the molding difficulty at the time of injection molding is high. Moreover, in the preform 200, when the thin portion 220 is provided so that the inner container 20 contracts regularly, the molding difficulty at the time of injection molding becomes higher. Therefore, in order to ensure the moldability of the preform 200 at the time of injection molding, it is important not to make the wall thickness of the thin portion 220 too thin.

Therefore, in the multiple container 1, a thin portion 220 having a wall thickness capable of ensuring moldability at the time of injection molding is provided in the preform 200, and the inner container 20 contracts regularly after the biaxially stretched blow molding of the preform 200. It is configured so that the thin portion 22 is provided with the thickness to be formed.

Specifically, as shown in FIG. 2, the multiple container 1 is configured such that the cross-sectional shape of the body portion 5 of the outer container 10 and the inner container 20 has a deformed shape different from the circular shape. In other words, in the cross section of the outer container 10 and the body portion 5 of the inner container 20, the multiple container 1 is configured such that the shapes of the outer container 10 and the inner container 20 are different from the circular shape. The irregular shape is, for example, a polygonal shape such as the quadrangle shown in FIG. Preferably, the cross-sectional shape of the body portion 5 of the outer container 10 and the inner container 20 is a regular polygonal shape.

Further, in the multilayer container 1, the ratio of the thickness of the inner container 20 to the thickness of the outer container 10 is the longest distance from the central axis Z in the cross section of the outer container 10 and the body 5 of the inner container 20. It is configured to be the minimum in the portion 15 and the maximum in the shortest portion 16 having the shortest distance from the central axis Z. That is, in the cross section of the outer container 10 and the body portion 5 of the inner container 20, in the multiple container 1, the thin portion 22 of the inner container 20 faces the longest portion 15 of the outer container 10 having the longest distance from the central axis Z. It is provided at the place where it is used. In this cross section, the non-thin portion 23 of the inner container 20 is provided at least including a portion facing the shortest portion 16 of the outer container 10 having the shortest distance from the central axis Z. In the cross section of the body portion 5 of the outer container 10 having a polygonal shape, the corner portion of the outer container 10 corresponds to the longest portion 15, and the midpoint portion of the side of the outer container 10 corresponds to the shortest portion 16. That is, the portion where the thin portion 22 of the inner container 20 is provided is a polygonal corner portion formed by the cross-sectional shape of the body portion 5 of the inner container 20. The portion of the inner container 20 where the non-thin wall portion 23 is provided is a polygonal side portion formed by the cross-sectional shape of the body portion 5 of the inner container 20.

Since the longest portion 15 of the outer container 10 has the longest distance from the central axis Z in the radial direction among the body portions 5 of the outer container 10, the stretching ratio in the radial direction in biaxial stretching blow molding is the highest. Therefore, the portion of the inner container 20 facing the longest portion 15 is the portion of the body portion 5 of the inner container 20 that has the highest radial stretching ratio in biaxial stretching blow molding. On the other hand, the shortest portion 16 of the outer container 10 has the shortest distance from the central axis Z in the radial direction among the body portions 5 of the outer container 10, and therefore has the lowest radial stretching ratio in biaxial stretching blow molding. .. Therefore, the portion of the inner container 20 facing the shortest portion 16 is the portion of the body portion 5 of the inner container 20 that has the lowest radial stretching ratio in biaxial stretching blow molding.

That is, in the multiple container 1, the thin-walled portion 22 is provided at a position facing the longest portion 15 of the outer container 10, so that the thin-walled portion 22 is provided at the portion of the body portion 5 of the inner container 20 where the stretching ratio in the radial direction is the highest. It will be provided. As a result, in the multiple container 1, even if the wall thickness of the thin wall portion 220 provided in the preform 200 corresponding to the inner container 20 is not made too thin, the wall thickness of the thin wall portion 22 is sufficient after biaxial stretching blow molding. Can be thinned to.

In the cross section of the outer container 10 and the body 5 of the inner container 20, the thickness of the body 5 of the inner container 20 is the minimum thickness of the thin portion 22 provided at a position facing the longest portion 15 of the outer container 10. It becomes Ta, and the maximum thickness Tb is obtained at a portion facing the shortest portion 16 of the outer container 10. That is, the thickness of the body portion 5 of the inner container 20 is the minimum thickness Ta at the polygonal corner portion formed by the cross-sectional shape of the body portion 5 of the inner container 20, and the cross-sectional shape of the body portion 5 of the inner container 20. The maximum thickness is Tb at the midpoint of the side of the polygon formed by. The minimum thickness Ta is preferably 70% or less, particularly 60% or less of the maximum thickness Tb.

The portion of the body 5 of the inner container 20 having the minimum thickness Ta is the most easily bent in the body 5 of the inner container 20, and the portion of the body 5 of the inner container 20 having the maximum thickness Tb is the inner container. It is the most difficult to bend in the body 5 of 20. Therefore, when the inner container 20 contracts, the thin-walled portion 22 which is the portion having the minimum thickness Ta becomes the starting point of the contraction deformation of the inner container 20 and first bends and contracts in the body portion 5 of the inner container 20. It tends to be the ridgeline of the inner container 20. Then, the non-thin portion 23 including the portion having the maximum thickness Tb is likely to be deformed so as to bend inward in the radial direction after the thin portion 22 is bent when the inner container 20 contracts. As a result, in the multiple container 1, the body portion 5 of the inner container 20 can be regularly contracted in such a manner that it is folded as shown in FIG.

When the minimum thickness Ta exceeds 70% of the maximum thickness Tb, the wall thickness difference between the thin portion 22 which is the minimum thickness Ta and the non-thin portion 23 including the portion having the maximum thickness Tb is small. Therefore, there is no significant difference between the thin-walled portion 22 and the non-thin-walled portion 23. For this reason, the thin-walled portion 22 is not likely to break before the non-thin-walled portion 23, and is unlikely to be the starting point of contraction deformation of the inner container 20, so that the inner container 20 is less likely to contract regularly. For this reason, in the multiple container 1, it is preferable that the minimum thickness Ta of the body 5 of the inner container 20 is 70% or less, particularly 60% or less of the maximum thickness Tb.

[Embodiment 1: Configuration of preform for multiple containers]
FIG. 4 is a diagram schematically showing a vertical cross section of the preforms 100 and 200 for manufacturing the multiple container 1 shown in FIG. FIG. 5 is a diagram schematically showing a cross section of preforms 100 and 200 cut in a plane including the VV line shown in FIG.

The multilayer container 1 is manufactured by biaxially stretching blow molding the preforms 100 and 200 formed into a bottomed tubular shape by injection molding or the like. As shown in FIG. 4, the preforms 100 and 200 correspond to the mouth portion 3 of the multiple container 1, the non-stretched portion M which is a portion not stretched by biaxial stretching blow molding, and the shoulder portion 4 of the multiple container 1. , Corresponding to the body portion 5 and the bottom portion 6, and is composed of a stretched portion N which is a portion stretched by biaxial stretching blow molding. The preform 100 is a preform corresponding to the outer container 10, and the preform 200 is a preform corresponding to the inner container 20.

In the present embodiment, the preform 100 corresponding to the outer container 10 is also referred to as an "outer preform 100", and the preform 200 corresponding to the inner container 20 is also referred to as an "inner preform 200". The outer preform 100 and the inner preform 200 are preforms for multiple containers for producing the multiple container 1 by biaxial stretching blow molding.

The outer preform 100 is provided with an outside air introduction hole 11 and a support ring for a portion corresponding to the mouth portion 3 of the outer container 10, and is provided with a cap mounting portion.

The inner preform 200 has a mouth portion 203 corresponding to the mouth portion 3 of the inner container 20, an inclined portion 204 extending downward from the mouth portion 203 while narrowing inward in the radial direction, and a downward portion along the axial direction from the inclined portion 204. It is provided with a straight body portion 205 extending downwardly from the straight body portion 205 and a bottom portion 206 extending downward from the straight body portion 205 and closing the straight body portion 205. The inclined portion 204 includes an upper inclined portion 204a connected to the mouth portion 203 and a lower inclined portion 204b connected to the straight body portion 205.

In the inner preform 200, the mouth portion 203 corresponds to the mouth portion 3 of the inner container 20, the upper inclined portion 204a corresponds to the shoulder portion 4 of the inner container 20, and the lower inclined portion 204b and the straight body portion 205 correspond to the inner container. The bottom portion 206 corresponds to the body portion 5 of the inner container 20 and corresponds to the bottom portion 6 of the inner container 20.

As shown in FIG. 5, the straight body portion 205 of the inner preform 200 is provided with a thin-walled portion 220 corresponding to the thin-walled portion 22 so that the thin-walled portion 22 is provided on the body portion 5 of the inner container 20. The thin-walled portion 220 is a portion whose wall thickness is thinner than that of the non-thin-walled portion 230. The non-thin portion 230 is another portion of the straight body portion 205 of the inner preform 200 in which the thin portion 220 is not provided, and corresponds to the non-thin portion 23 of the inner container 20.

The thin portion 220 is provided so as to have a width in the circumferential direction and extend in the axial direction. Specifically, the thin-walled portion 220 is formed in the straight body portion 205 in a groove shape having a width in the circumferential direction and extending along the axial direction. The thin-walled portions 220 are provided at a plurality of locations at intervals in the circumferential direction according to the cross-sectional shape of the body portion 5 of the outer container 10 and the inner container 20. That is, the thin-walled portion 220 is provided at a portion facing the portion in the blow mold corresponding to the longest portion 15 of the outer container 10. The non-thin wall portion 230 is provided at a portion facing the portion in the blow mold corresponding to the shortest portion 16 of the outer container 10. When the cross-sectional shape of the body 5 of the outer container 10 and the inner container 20 is polygonal, the portion of the inner preform 200 where the thin portion 220 is provided is the inner container 20 in the cross section of the straight body 205 of the inner preform 200. This is a portion corresponding to the corner portion of the polygon formed by the cross-sectional shape of the body portion 5. A line segment connecting a plurality of thin-walled portions 220 in order along the circumferential direction has a shape substantially similar to this polygon. It is preferable that the plurality of thin-walled portions 220 are provided so that the distances to their respective central axes Z are substantially the same. It is preferable that the plurality of thin-walled portions 220 are provided so as to be point-symmetrical with the central axis Z as the center of symmetry in the cross section.

In the cross section of the straight body portion 205 of the inner preform 200, the minimum thickness Ta'of the straight body portion 205 is the thickness of the thin wall portion 220, and the maximum thickness Tb'of the straight body portion 205 is the thickness of the non-thin wall portion 230. The thickness. The minimum thickness Ta'is preferably 80% or less, particularly 70% or less of the maximum thickness Tb', from the viewpoint of regular shrinkage of the inner container 20. The minimum thickness Ta'is preferably 200 μm or more from the viewpoint of moldability of the inner preform 200 during injection molding and moldability of the inner preform 200 during biaxial stretch blow molding. If the minimum thickness Ta'is less than 200 μm, it is difficult to stably mold the thin-walled portion 220 having an appropriate wall thickness during injection molding, and the thin-walled portion 220 is excessively stretched during biaxial stretching blow molding. This is because it is easy to break, so that molding defects are likely to occur.

Further, the axial length of the thin portion 220 is preferably 30% or more, particularly 50% or more, of the axial length of the stretched portion N of the inner preform 200 from the viewpoint of regular contraction of the inner container 20. Is. The axial length of the stretched portion N of the inner preform 200 is the axial length of the inclined portion 204, the straight body portion 205, and the bottom portion 206 of the inner preform 200. The axial position of the thin-walled portion 220 is preferably a position close to the bottom portion 206 among the axial positions of the straight body portion 205. This is to prevent the bottom 6 of the inner container 20 from rising and the inner container 20 from contracting irregularly.

[Embodiment 1: Manufacturing method of multiple containers]
As shown in FIG. 4, the outer preform 100 and the inner preform 200 are multiplexed by inserting the inner preform 200 into the outer preform 100 and simultaneously performing biaxial blow molding in a state where both are overlapped. It is molded into container 1. This biaxial stretch blow molding method for the multiple container 1 is also referred to as a stack preform method.

In the stack preform method, the outer preform 100 and the inner preform 200 are placed in a heated blow mold in a state where they are overlapped with each other. Then, in the stack preform method, the inside of the inner preform 200 is stretched in the axial direction by a stretching rod, and blow air is blown into the inner preform 200 to stretch it in the radial and circumferential directions, thereby pressing the inner preform 200 against the blow die to form a blow die. The outer container 10 and the inner container 20 having the corresponding shapes are molded.

The blow mold is formed in a shape corresponding to the deformed shape so that the cross-sectional shape of the body portion 5 of the outer container 10 and the inner container 20 has a deformed shape. When the outer preform 100 and the inner preform 200 are installed in the blow mold, the thin portion 220 of the inner preform 200 and the portion in the blow mold corresponding to the longest portion 15 of the outer container 10 face each other. The outer preform 100 and the inner preform 200 are installed in the. As a result, the outer preform 100 and the inner preform 200 are formed into a multi-layer container 1 provided with a thin portion 22 of the inner container 20 at a position facing the longest portion 15 of the outer container 10.

In this blow molding process, the inner preform 200 is stretched at the same time as the outer preform 100 with its outer surface in close contact with the inner surface of the outer preform 100. Therefore, the thin portion 220 of the inner preform 200 is stretched together with the non-thin portion 230 while its outer surface is in contact with the inner surface of the outer preform 100. That is, in the stack preform method, the stretching of the thin portion 220 of the inner preform 200 can be regulated on the inner surface of the outer preform 100. As a result, in the stack preform method, since only the thin-walled portion 220 is not excessively stretched, it is possible to prevent the thin-walled portion 220 from being excessively thinned and broken, and it is possible to suppress the occurrence of molding defects.

On the other hand, in the biaxial stretching blow molding method for multiple containers, the outer preform 100 is stretched to form the outer container 10 in the blow mold, and then the inner preform 200 is stretched inside the outer container 10. There is also a reform-in-bottle method. However, in the preform-in-bottle method, since the inner preform 200 is not stretched at the same time as the outer preform 100, the stretching of the thin portion 220 is not regulated on the inner surface of the outer preform 100. Therefore, in the preform-in-bottle method, the thin portion 220 of the inner preform 200 may be excessively stretched, resulting in molding defects such as breakage. Therefore, the preform-in-bottle method is not suitable as a biaxial stretch blow molding method for the multilayer container 1 provided with the thin-walled portion 22 as described above.

[Embodiment 1: Action / Effect]
As described above, in the multiple container 1 according to the first embodiment, the ratio of the thickness of the inner container 20 to the thickness of the outer container 10 in the cross section of the body 5 of the outer container 10 and the inner container 20 is the central axis. It is configured so that the longest portion 15 having the longest distance from Z is the minimum, and the shortest portion 16 having the shortest distance from the central axis Z is the maximum. With such a configuration, the multiple container 1 according to the first embodiment is provided with a thin portion 22 with respect to the body portion 5 of the inner container 20. The thin-walled portions 22 extend in the axial direction and are provided at a plurality of locations at intervals in the circumferential direction. Then, in the cross section of the body portion 5 of the outer container 10 and the inner container 20, the shapes of the outer container 10 and the inner container 20 are polygonal, and the thin-walled portion 22 faces the longest portion 15 of the outer container 10. It is provided at the place where it is used.

Therefore, in the multiple container 1 according to the first embodiment, when the inner container 20 contracts as the contents decrease, the thin-walled portion 22 becomes the starting point of the contraction deformation, and the inner container 20 contracts regularly. The contraction mode of the vessel 20 can be regulated. As a result, in the multiple container 1 according to the first embodiment, the flow path of the contents can be secured in the inner container 20 even at the final stage of use when the capacity of the contents is reduced, so that the contents can be completely poured out. It is possible to prevent the container from being left behind.

In addition, in the multiple container 1 according to the first embodiment, the thin-walled portion 22 is provided in the body portion 5 of the inner container 20 at the position where the stretching ratio in the radial direction is the highest. As a result, in the multiple container 1 according to the first embodiment, even if the wall thickness of the thin wall portion 220 provided in the inner preform 200 is not made too thin, the wall thickness of the thin wall portion 22 is sufficient after biaxial stretching blow molding. Can be thinned to. As a result, in the multiple container 1 according to the first embodiment, the preform 200 is provided with a thin portion 220 having a wall thickness that can ensure moldability at the time of injection molding, and the inner container is formed after the biaxial stretching blow molding of the preform 200. A thin portion 22 having a wall thickness capable of regularly shrinking 20 can be provided.

As described above, the multiple container 1 according to the first embodiment can achieve both regular contraction of the inner container 20 and ensuring moldability. As a result, the multiple container 1 according to the first embodiment can achieve both suppression of residual contents and ensuring productivity.

Further, in the multiple container 1 according to the first embodiment, in the cross section of the outer container 10 and the body 5 of the inner container 20, the thickness of the body 5 of the inner container 20 faces the shortest portion 16 of the outer container 10. The maximum thickness Tb is obtained at the portion, and the minimum thickness Ta is obtained at the thin portion 22 provided at the portion facing the longest portion 15 of the outer container 10. Therefore, when the inner container 20 contracts, the thin-walled portion 22 which is the portion having the minimum thickness Ta in the body portion 5 of the inner container 20 is first bent in the body portion 5 of the inner container 20 and contracted. The non-thin wall portion 23 including the portion having the maximum thickness Tb is liable to be deformed so as to bend inward in the radial direction. Thereby, in the multiple container 1 according to the first embodiment, the contraction mode of the inner container 20 can be regulated to a regular mode such that the body portion 5 is folded. Therefore, in the multiple container 1 according to the first embodiment, the inner container 20 can be regularly shrunk at a higher level while ensuring moldability. As a result, the multiple container 1 according to the first embodiment can achieve both suppression of residual contents and securing of productivity at a higher level.

Further, in the multiple container 1 according to the first embodiment, the minimum thickness Ta of the body portion 5 of the inner container 20 is 70% or less of the maximum thickness Tb. As a result, in the multiple container 1 according to the first embodiment, since the thin-walled portion 22 and the non-thin-walled portion 23 can be surely provided with a wall thickness difference, the thin-walled portion 22 is likely to be the starting point of shrinkage deformation, and the inner container is surely provided. 20 can be contracted regularly. Therefore, in the multiple container 1 according to the first embodiment, the inner container 20 can be more reliably and regularly contracted while ensuring moldability. As a result, the multiple container 1 according to the first embodiment can more surely achieve both suppression of residual contents and securing of productivity.

Further, in the multiple container 1 according to the first embodiment, the outer container 10 and the inner container 20 are manufactured by simultaneously biaxially stretching blow molding the outer preform 100 and the inner preform 200 in a state of being overlapped with each other. Ru. Therefore, in the multiple container 1 according to the first embodiment, the inner container 20 is regularly contracted while ensuring the moldability of the inner preform 200 at the time of injection molding and the moldability at the time of biaxial stretching blow molding. be able to. Therefore, in the multiple container 1 according to the first embodiment, it is possible to stably suppress the residual contents and secure the productivity.

Further, in the multiple container 1 according to the first embodiment, the thin-walled portion 22 of the inner container 20 is bent so as to bring the inner surfaces of the non-thin-walled portions 23 close to each other, thereby restricting the contraction mode of the inner container 20. Therefore, in the multiple container 1 according to the first embodiment, the inner container 20 is regularly provided only by providing a wall thickness difference in the body portion 5 of the inner container 20 in the existing manufacturing process without using any special means. Shrinkage can be achieved. Therefore, in the multiple container 1 according to the first embodiment, it is possible to easily achieve both regular contraction of the inner container 20 and ensuring moldability. As a result, the multiple container 1 according to the first embodiment can easily achieve both suppression of residual contents and ensuring productivity.

In the multiple container 1 according to the first embodiment, the thin-walled portion 22 of the inner container 20 does not need to be provided at all the positions facing the longest portion 15 of the outer container 10. That is, the thin-walled portion 22 of the inner container 20 does not have to be provided at all the corner portions of the polygon formed by the cross-sectional shape of the body portion 5 of the inner container 20, and the number of the corner portions of the polygon and the thin-walled portion The number of places where 22 is provided may be different.

[Other Embodiments]
The multiple container 1 according to the second embodiment will be described. In the description of the multiple container 1 according to the second embodiment, the description relating to the same configuration and operation as the multiple container 1 according to the first embodiment will be omitted because the description will be duplicated.

FIG. 6 is a diagram for explaining the multiple container 1 according to the second embodiment. FIG. 7 is a diagram for explaining preforms 100 and 200 for manufacturing the multiple container 1 shown in FIG.

FIG. 6 shows a cross section of the body portion 5 of the outer container 10 and the inner container 20 according to the second embodiment. FIG. 7 shows a cross section of the preforms 100 and 200 when the preforms 100 and 200 according to the second embodiment are cut in a plane orthogonal to the straight body portion 205.

The multiple container 1 according to the first embodiment is configured such that the cross-sectional shape of the body portion 5 of the outer container 10 and the inner container 20 has a polygonal shape as shown in FIG. On the other hand, the multiple container 1 according to the second embodiment is configured such that the cross-sectional shape of the body portion 5 of the outer container 10 and the inner container 20 has an elliptical shape as shown in FIG.

In the multiple container 1 according to the second embodiment, in the cross section of the body portion 5 of the outer container 10 having an elliptical shape, the intersection with the long axis of the outer container 10 corresponds to the longest portion 15, and the outer container 10 is short. The intersection with the shaft corresponds to the shortest portion 16. The portion of the inner container 20 where the thin portion 22 is provided is an intersection with the elliptical long axis formed by the cross-sectional shape of the body portion 5 of the inner container 20. The portion of the inner container 20 where the non-thin wall portion 23 is provided is a portion other than the intersection with the elliptical long axis formed by the cross-sectional shape of the body portion 5 of the inner container 20.

The thickness of the body portion 5 of the inner container 20 is the minimum thickness Ta at the thin-walled portion 22 provided at the portion facing the longest portion 15 of the outer container 10, and the thickness of the body portion 5 faces the shortest portion 16 of the outer container 10. The maximum thickness is Tb. That is, the thickness of the body portion 5 of the inner container 20 becomes the minimum thickness Ta at the intersection with the elliptical long axis formed by the cross-sectional shape of the body portion 5 of the inner container 20, and the body portion 5 of the inner container 20. The maximum thickness is Tb at the intersection with the elliptical minor axis formed by the cross-sectional shape of. The minimum thickness Ta is 70% or less, particularly 60% or less of the maximum thickness Tb.

Further, as shown in FIG. 7, two thin-walled portions 220 are provided on the straight body portion 205 of the inner preform 200 according to the second embodiment. In the cross section of the straight body portion 205 of the inner preform 200, the portion where the two thin-walled parts 220 are provided corresponds to the intersection with the elliptical long axis formed by the cross-sectional shape of the body portion 5 of the inner container 20. It is a part. The two thin-walled portions 220 are provided so as to face each other with the central axis Z interposed therebetween.

In the multiple container 1 according to the second embodiment, when the inner container 20 contracts, the thin-walled portion 22 becomes the starting point of the contraction deformation of the inner container 20 and first bends in the body portion 5 of the inner container 20, and the non-thin-walled portion 23 Is easily deformed so as to approach the central axis Z while reducing its curvature. Thereby, in the multiple container 1 according to the second embodiment, the contraction mode of the inner container 20 can be regulated to a regular mode such that the body portion 5 is folded. Therefore, the multiple container 1 according to the second embodiment can achieve both regular contraction of the inner container 20 and ensuring moldability, as in the first embodiment. As a result, the multiple container 1 according to the second embodiment can achieve both suppression of residual contents and ensuring productivity.

In the above-described embodiment, the thin-walled portion 220 of the inner preform 200 may be provided not only on the straight body portion 205 but also on the lower inclined portion 204b. As a result, the thin portion 22 of the inner container 20 is provided in the entire axial direction of the body portion 5 of the inner container 20, so that the inner container 20 can be reliably and regularly contracted. Further, the thin-walled portion 220 of the inner preform 200 may be provided not only on the straight body portion 205 and the lower inclined portion 204b, but also on the upper inclined portion 204a. As a result, the thin portion 22 of the inner container 20 is provided not only on the body portion 5 of the inner container 20 but also on the shoulder portion 4, so that the inner container 20 can be contracted more reliably and regularly.

In the above-described embodiment, the multiple container 1 is a container in which the outer container 10 constitutes the outer shell of the multiple container 1 and the inner container 20 contains the contents. However, the multiple container 1 is not limited to a container in which the outer container 10 constitutes the outer shell of the multiple container 1 and the inner container 20 accommodates the contents. That is, in the multiple container 1, the container forming the outer shell of the multiple container 1 may be provided further outside the outer container 10, or the container for accommodating the contents may be provided further inside the inner container 20. In this way, the multiple container 1 may function as a laminate in which the outer container 10 and the inner container 20 are flankably laminated adjacent to each other and form a gap A between them, as a matter of course. It may be a container having a triple or more multiple structure capable of forming a plurality of voids A.

In the above-described embodiment, the case where the present invention is applied to the multiple container 1 having a multiple structure including the outer container 10 and the inner container 20 and the preforms 100 and 200 thereof has been described as an example. However, the present invention is also applicable to containers having a single structure instead of a multiple structure, such as PET bottles.

Specifically, this container has a bottle shape, and thin-walled portions extending in the axial direction are provided at a plurality of locations at intervals in the circumferential direction with respect to the body portion thereof. The container has a deformed shape different from the circular shape in the cross section of the body portion, and the thin-walled portion is provided at the longest portion having the longest distance from the central axis of the container. With such a configuration, when the container is crushed so as not to be bulky at the time of disposal, that is, when the container is contracted and deformed, the thin-walled portion becomes the starting point of the contraction deformation of the container, so that the container contracts regularly. The contraction mode of the container can be regulated. Further, in this container, even if the wall thickness of the thin wall portion provided on the preform is not made too thin, the wall thickness of the thin wall portion provided on the container can be sufficiently thinned after biaxial stretching blow molding. , A thin portion capable of regularly shrinking the container can be provided while ensuring moldability at the time of injection molding. Therefore, this container can achieve both regular shrinkage of the container and ensuring moldability.

Preferably, in the cross section of the body, the thickness of the body is the shortest at the shortest distance from the center axis of the container and the maximum thickness at the shortest part, and the distance from the center axis of the container is the longest. The thinnest part provided at the longest part has the minimum thickness. As a result, this container can achieve both regular shrinkage of the container and ensuring moldability at a high level.

Preferably, the container has a body having a minimum thickness of 70% or less of the maximum thickness. As a result, the container can more reliably achieve both regular shrinkage of the container and ensuring moldability.

[Other]
In the above-described embodiment, the multiple container 1 corresponds to an example of the "multiple container" described in the claims. The outer container 10 corresponds to an example of the “outer container” described in the claims. The inner container 20 corresponds to an example of the "inner container" described in the claims. The body portion 5 corresponds to an example of the “body portion” described in the claims. The longest part 15 corresponds to an example of the "longest part" described in the claims. The shortest part 16 corresponds to an example of the "shortest part" described in the claims. The thin-walled portion 22 corresponds to an example of the “thin-walled portion” described in the claims. The outer preform 100 corresponds to an example of the "outer preform" described in the claims. The inner preform 200 corresponds to an example of the "inner preform" described in the claims. The central axis Z corresponds to an example of the “central axis” described in the claims.

In the above-described embodiments, the techniques can be applied to each other, including modifications. The above-described embodiment does not limit the content of the present invention, and changes can be made without departing from the scope of claims.

The terms used in the above embodiments and claims should be construed as non-limiting terms. For example, the term "contains" should be construed as "not limited to what is described as including." The term "contains" should be construed as "not limited to what is described as containing." The term "prepared" should be construed as "not limited to what is described as prepared." The term "have" should be construed as "not limited to what is described as having."

1 Multiple container 3 Mouth 4 Shoulder 5 Body 6 Bottom 10 Outer container 11 Outside air introduction hole 15 Longest part 16 Shortest part 20 Inner container 21 Outlet 22 Thin-walled part 23 Non-thin-walled part 100 Outer preform 200 Inner preform 203 Part 204 Inclined part 204a Upper inclined part 204b Lower inclined part 205 Straight body part 206 Bottom part 220 Thin-walled part 230 Non-thin-walled part A Void M Non-stretched part N Stretched part S Storage space Ta Minimum thickness of the body of the container Tb Contents Maximum thickness of the body of the vessel Ta'Minimum thickness of the straight body of the inner preform Tb'Maximum thickness of the straight body of the inner preform Z Central axis

Claims (5)

A bottle-shaped multiple container in which an inner container and an outer container containing the inner container are detachably laminated.
In the cross section of the body of the outer container and the inner container,
The shapes of the outer container and the inner container are different from the circular shape.
The ratio of the thickness of the inner container to the thickness of the outer container is the smallest at the longest portion where the distance from the central axis of the outer container is the longest, and the shortest distance from the central axis of the outer container is the shortest. The largest in the department,
Multiple containers. On the body of the inner container, thin-walled portions extending in the axial direction are provided at a plurality of locations at intervals in the circumferential direction.
In the cross section, the thickness of the body of the inner container is
The maximum thickness is reached at the portion of the outer container facing the shortest portion.
The thin-walled portion provided at a position facing the longest portion of the outer container has the minimum thickness.
The multiple container according to claim 1. The minimum thickness is 70% or less of the maximum thickness.
The multiple container according to claim 2. The inner container shrinks as the contents decrease,
The thin-walled portion regulates the contraction mode of the inner container by bending so that the inner surfaces of the non-thin-walled portions in the body portion of the inner container come close to each other.
The multiple container according to claim 2 or 3. The outer container and the inner container are biaxially stretched at the same time in a state where the inner preform which is the preform corresponding to the inner container and the outer preform which is the preform corresponding to the outer container are overlapped. Manufactured by blow molding,
The multiple container according to any one of claims 1 to 4.