JP2024055484A - Double container and method for joining double container - Google Patents

Abstract

[Problem] To provide a method for joining a double container that is excellent in design and allows easy joining of an outer container and an inner container, and a double container obtained by the method. [Solution] A double container in which an outer container and an inner container are joined, in which the outer wall of the outer container and the joining side wall of the inner container contribute to the joining, and the engagement surfaces that contribute to the joining of the outer container and the inner container are two pairs of surfaces where the outer wall and the joining side wall face each other. [Selected drawing] Figure 2

Description

The present invention relates to a double container in which an outer container and an inner container made of plastic are integrated.

Plastic containers are known in which a transparent inner container and a transparent outer container are integrated to form a double structure for the purposes of protecting the contents, improving the design of the container, making it easier to fill the container with contents, making it easier to manufacture the container, and making it possible to remove the contents without leaving any behind. Such technology is described, for example, in JP 2020-128225 A (Patent Document 1) or JP Patent No. 4911401 A (Patent Document 2).

JP 2020-128225 A Patent No. 4911401

The technology described in JP 2020-128225 A (Patent Document 1) claims that the joints of the double container are joined by fusing using heat or ultrasound, or by bonding using an adhesive. However, because the concave and convex parts of each double container are joined, the surface is made indented, which deteriorates the feel and appearance, making the container less appealing in design and making it difficult to adopt as a packaging container for shampoo or conditioner, which is intended to create a stylish look.
In addition, the technology described in Japanese Patent No. 4911401 (Patent Document 2) is characterized in that an inclined surface is formed on each of the outer container and the inner container to bring them into contact with each other, and the abutting inclined surfaces are welded and joined by irradiating a laser beam. However, this technology has the drawback that the joining is performed by the inclined surfaces, and therefore the engagement is insufficient, making it difficult to achieve a stable joining.

This disclosure provides a method for joining a double container that is excellent in design and allows easy joining of an outer container and an inner container, and a double container obtained by this method.

In order to solve the above problem, the present disclosure has the following configuration. That is, it is a double container in which an outer container and an inner container are joined, in which the outer wall of the outer container and the joining side wall of the inner container contribute to the joining, and the engagement surfaces that contribute to the joining of the outer container and the inner container are two pairs of surfaces where the outer wall and the joining side wall face each other.

This double container is made up of an outer container and an inner container joined together, and the outer wall of the outer container and the joining side wall of the inner container contribute to the joining. The engagement surfaces that contribute to the joining of the outer container and the inner container are two pairs of surfaces where the outer wall and the joining side wall face each other. This simplifies the engagement structure and makes molding easy, resulting in high dimensional stability, meaning that molding can be done within a specified scale range. This reduces the likelihood of producing defective products, and increases yield. In addition, the outer container and the inner container can be easily stacked, making it highly easy to work with, meaning that work can be done efficiently without unnecessary work.

One aspect of the present disclosure is a double container in which a protrusion portion protruding from a base end surface is formed at the end of the outer wall, and one pair of the two opposing pairs of surfaces is the outer peripheral surface of the protrusion portion of the outer container and the inner peripheral surface of the joining side wall of the inner container, and the other pair of the two opposing pairs of surfaces is the base end surface of the outer container and the end surface of the joining side wall of the inner container.
In the present disclosure, a protrusion protruding from a base end face is formed at the end of the outer wall, and one pair of the two opposing pairs of surfaces is the outer peripheral surface of the protrusion part of the outer container and the inner peripheral surface of the joining side wall of the inner container, and the other pair of the two opposing pairs of surfaces is the base end face of the outer container and the end face of the joining side wall of the inner container, so that an engagement surface can be formed simply by forming a protrusion part at the end of the outer container and simply by forming a joining wall part in the inner container, making it easy to mold both containers.

One aspect of the present disclosure is a double container having an ultrasonic rib on the inner periphery of the base end surface of the outer container. Since one aspect of the present disclosure is a double container having an ultrasonic rib on the inner periphery of the base end surface of the outer container, the outer container and the inner container can be easily welded by ultrasonic welding. In addition, since the ultrasonic rib is formed on the base end surface of the outer container, it is easy to form a molding die, and the ultrasonic rib can be easily provided.

One aspect of the present disclosure is a double container in which, of the two pairs of opposing surfaces, at least a pair of surfaces consisting of the base end surface of the outer container and the end surface of the joining side wall of the inner container are fixedly attached. One aspect of the present disclosure is a double container in which, of the two pairs of opposing surfaces, at least a pair of surfaces consisting of the base end surface of the outer container and the end surface of the joining side wall of the inner container are fixedly attached. Therefore, the outer container and the inner container can be integrated by fixing at least this pair of surfaces. This makes the fixing process easy and increases the manufacturing efficiency of the double container.

One aspect of the present disclosure is a double container in which, of the two pairs of opposing surfaces, a pair of surfaces along the joining direction of the outer container and the inner container are formed as opposing inclined surfaces. One aspect of the present disclosure is a double container in which, of the two pairs of opposing surfaces, a pair of surfaces along the joining direction of the outer container and the inner container are formed as opposing inclined surfaces, making it easier to fit the inner container into the outer container, and facilitating the fitting work before the two containers are fixed together. In addition, by forming the surfaces as inclined surfaces, the resin melted from the ultrasonic ribs can easily flow into the space between the pair of surfaces along the joining direction of the outer container and the inner container. Furthermore, the pair of surfaces along the joining direction of the outer container and the inner container are easily melted during ultrasonic fusion, making it easier to weld this pair of surfaces.

One aspect of the present disclosure is a double container in which, of the two pairs of opposing surfaces, a pair of surfaces along the joining direction of the outer container and the inner container are each formed as an uneven surface. One aspect of the present disclosure is a double container in which, of the two pairs of opposing surfaces, a pair of surfaces along the joining direction of the outer container and the inner container are each formed as an uneven surface, so that the surface becomes rougher than if the surfaces were smooth, and the adhesive strength of the molten resin is increased. Therefore, the double container has excellent adhesion between the outer container and the inner container.

One aspect of the present disclosure can be a double container in which the intersection between the end face of the joining side wall and the inner peripheral surface of the inner container is chamfered. One aspect of the present disclosure is a double container in which the intersection between the end face of the joining side wall and the inner peripheral surface of the inner container is chamfered, so that the resin melted from the ultrasonic rib easily flows into the inner peripheral surface of the joining side wall. This can increase the adhesive strength between the outer container and the inner container.

One aspect of the present disclosure can be a double container in which the intersection of the base end face of the outer container and the outer peripheral surface of the protruding piece is formed as a L-shaped recess in cross section. One aspect of the present disclosure is a double container in which the intersection of the base end face of the outer container and the outer peripheral surface of the protruding piece is formed as a L-shaped recess in cross section. Since the resin melted from the ultrasonic rib enters this recess, the adhesive strength between the outer container and the molten resin is increased, and therefore the adhesive strength between the outer container and the inner container is also increased.

One aspect of the present disclosure is a method for joining a double container in which both side walls of an outer container having an outer wall and an inner container having a joining side wall are joined, in which the outer wall and the joining side wall are engaged at two pairs of opposing surfaces, and at least one of the two pairs of opposing surfaces that is perpendicular to the joining direction of the outer container and the inner container is fixed by ultrasonic welding to form a fixed surface.

One aspect of the present disclosure is a method for joining a double container in which both side walls of an outer container having an outer wall and an inner container having a joining side wall are joined, in which the outer wall and the joining side wall are engaged at two pairs of opposing surfaces, and at least one of the two pairs of opposing surfaces, which is a pair of surfaces perpendicular to the joining direction of the outer container and the inner container, is fixed by ultrasonic fusion to form a fixed surface, making it easy to manufacture the parts related to the joining of the outer container and the inner container. This makes it possible to reduce the manufacturing cost of the outer container and the inner container. In addition, the outer container and the inner container can be easily engaged, making manufacturing more efficient. Furthermore, since ultrasonic fusion is used, no adhesive is required, and the extra steps and costs involved in using an adhesive can be eliminated.

One aspect of the present disclosure is a method for joining double containers, in which an outer container is used in which a protruding piece is formed at the end of the outer wall so as to protrude from the base end face, and an ultrasonic rib is provided on the inner periphery of the base end face, and at least the base end face and the end face of the joining side wall of the inner container are joined by ultrasonic welding to form a joining surface.

One aspect of the present disclosure is a method for joining a double container in which an outer container is used in which a protruding piece is formed at the end of the outer wall protruding from the base end face, an ultrasonic rib is provided on the inner periphery of the base end face, and at least the base end face and the end face of the joining side wall of the inner container are fixed to each other by ultrasonic welding to form a fixed surface. This makes it easy to attach the method to an ultrasonic fusion machine, and makes it easy to carry out the ultrasonic welding process. In addition, an ultrasonic horn can be applied to the lid of the inner container. Furthermore, the fixed surface is the surface that receives pressure due to the weight of the inner container, improving the reliability of the fixation of the outer container and the inner container.

One aspect of the present disclosure is a method for joining a double container in which the two pairs of opposing surfaces are bonded together by ultrasonic welding to form a bonded surface. As one aspect of the present disclosure is a method for joining a double container in which the two pairs of opposing surfaces are bonded together by ultrasonic welding to form a bonded surface, the outer container and the inner container can be bonded together easily and reliably.

According to the method for joining a double container disclosed herein, the outer container and the inner container can be easily joined.
Furthermore, the double container of the present disclosure is a double container with excellent design.

FIG. 2 is a schematic front view showing a state in which a double container with a nozzle is used. FIG. 1 is an explanatory diagram illustrating how a double container can be formed from an outer container and an inner container. 3A is a plan view of the double container, and FIG. 3B is a front view of the double container and an enlarged partial cross-sectional view taken along line IIIB-IIIB of FIG. 3A. An enlarged cross-sectional view of the joint between the outer container and the inner container is shown.

The present disclosure will be described in more detail based on an embodiment. Fig. 1 is a schematic front view showing the state in which a double container 1 made of a plastic container according to the present disclosure is in use, and Fig. 2 shows its configuration. As shown in Fig. 2, the double container 1 shown in Fig. 1 is composed of an outer container 10 and an inner container 20, and is used as a packaging container for shampoo, conditioner, etc. by attaching a separate nozzle 2.

As shown in FIG. 2, the outer container 10 is formed in a cup shape with a bottom, and has a bottom surface 17 at its lower end that has at least a horizontal portion so that it can be placed on the floor, and a cylindrical outer wall 11 that rises upward from the bottom surface 17, and an opening 18 is formed at its upper end.
Meanwhile, the lower part of the inner container 20 is cup-shaped with a bottom, but the lower part is tapered to form a U-shaped bottom 27 that cannot stand up independently without the outer container. An inner wall 21 capable of accommodating the contents rises from the U-shaped bottom 27 on the side. At the upper part of the inner container 20, the inner wall 21 narrows to form a neck 26 to which the nozzle 2 is attached, while a lid 28 is formed that protrudes outward from the boundary between the neck 26 and the inner wall 21. The lid 28 has a joining side wall 22, which will be described later, and serves as a lid that closes the opening 18 of the outer container 10.

Figure 3 shows a schematic front view, schematic plan view, and partially enlarged cross-sectional view of the double container 1. This partially enlarged cross-sectional view shows an enlarged engagement portion that contributes to the joining of the outer container 10 and the inner container 20. That is, the outer container 10 has an outer wall 11, and the inner container 20 has a joining side wall 22. The outer wall 11 and the joining side wall 22 face each other at two pairs of surfaces, forming engagement surfaces that contribute to the joining of the outer container 10 and the inner container 20.

Referring also to Figure 4, which shows an enlarged view of the joint between the outer container 10 and the inner container 20, the outer container 10 has a protruding piece 13 formed at the end 12 of its outer wall 11, protruding from the base end surface 12a. The outer peripheral surface 13a of this protruding piece 13 and the inner peripheral surface 22a of the joint side wall 22 of the inner container 20 form a pair of opposing surfaces. In addition, the base end surface 12a of the outer container 10 and the end surface 22b of the joint side wall 22 of the inner container 20 form another pair of corresponding surfaces.

An ultrasonic rib 14 is provided on the base end surface 12a of the outer container 10. The ultrasonic rib 14 is melted by ultrasonic waves to bond the base end surface 12a to the end surface 22b of the inner container 20. The ultrasonic rib 14 is preferably provided on the base end surface 12a, more inward than the center. By providing it in such a position, it is easy to prevent the molten material of the ultrasonic rib 14 from spilling outward from the outer wall 11 and damaging the appearance, and the molten material easily flows into the gap between the protruding piece 13 of the outer container 10 and the inner surface 22a of the joining side wall 22, and these pair of surfaces can also be used as bonding surfaces, improving the bonding strength between the outer container 10 and the inner container 20.

In this case, it is preferable that the inner peripheral surface 22a of the joining side wall 22 and the outer peripheral surface 13a of the protruding piece 13, which form a pair of surfaces along the vertical direction in which the outer container 10 and the inner container 20 are joined, are formed as opposing inclined surfaces. In the example shown in FIG. 3, the inner peripheral surface 22a of the joining side wall 22 forms an inclined surface that slopes toward the center of the inner container 20 as it moves upward. Meanwhile, the outer peripheral surface 13a of the protruding piece 13 of the outer wall 11 also forms an inclined surface that slopes toward the center of the inner container 20 as it moves upward. Forming such an inclined surface makes it easier to fit the inner container 20 into the outer container 10.

It is also preferable that the inner peripheral surface 22a of the joining side wall 22 and the outer peripheral surface 13a of the protruding piece 13, which form a pair of surfaces along the vertical direction in which the outer container 10 and the inner container 20 are joined, are formed as non-smooth surfaces. A smooth surface is one in which you can see through the resin when a transparent resin is used, whereas a non-smooth surface is one in which you cannot see through the resin when a transparent resin is used. By deliberately not making the surface smooth, the surface becomes rough, improving the adhesive strength.

The intersection of the end face 22b of the joint side wall 22 and the inner peripheral surface 22a of the inner container 20, i.e., the point where both surfaces intersect at right angles, is preferably formed as a chamfered portion 23. On the other hand, the intersection of the base end face 12a of the outer container 10 and the outer peripheral surface 13a of the protruding piece 13, i.e., the point where both surfaces intersect at right angles, is preferably formed as a recess 15 with a L-shaped cross section.

The intersection of the end face 22b and the inner peripheral surface 22a is chamfered 23, which removes the corners and makes it easier for the molten resin from the ultrasonic rib 14 to flow between the outer peripheral surface 13a of the protruding piece 13 and the inner peripheral surface 22a of the joining side wall 22. On the other hand, the intersection of the base end face 12a and the outer peripheral surface 13a of the protruding piece 13 is formed as a recess 15 with a L-shaped cross section, which allows the molten resin to penetrate deep into the recess 15 and makes it difficult for the molten resin to peel off from the end 12.

Materials that can be used for the double container include polyethylene terephthalate resin (PET), acrylic resin, polymethylpentene resin (PMP), polypropylene resin, etc. Among these resins, PET is preferred because it is highly transparent, easy to mold, and has high strength.

To manufacture the double container 1, the outer container 10 and the inner container 20 are molded by injection molding or blow molding, and when the inner container 20 is fitted into the outer container 10, the mating surfaces of the two containers are engaged. Then, ultrasonic waves are applied from the lid 28 of the inner container 20 by an ultrasonic fusion machine, melting the ultrasonic ribs 14 and fusing the outer container 10 and the inner container 20. Although ultrasonic fusion is an easy method of fastening, it is also possible to heat-weld the mating surfaces of the outer container 10 and the inner container 20, or to apply an adhesive to these mating surfaces to fasten them together.

The above embodiment is an example of the present invention, and may further include known means and methods, and may be modified as appropriate without departing from the spirit of the present invention.

1 Double container, 2 Nozzle, 10 Outer container, 11 Outer wall, 12 End, 12a Base end surface, 13 Projection, 13a Outer surface, 14 Ultrasonic rib, 15 Recess, 17 Bottom surface, 18 Opening, 20 Inner container, 21 Inner wall, 22 Joint side wall, 22a Inner surface, 22b End surface, 23 Chamfered portion, 26 Neck portion, 27 U-shaped bottom, 28 Lid portion

Claims (11)

A double container in which the outer container and the inner container are joined together,
the outer wall of the outer container and the joining side wall of the inner container contribute to the joining;
A double container in which the engagement surfaces contributing to the joining of the outer container and the inner container are two pairs of opposing surfaces of the outer wall and the joining side wall. A protruding piece portion is formed at an end of the outer wall so as to protrude from a base end surface,
one pair of the two pairs of opposing surfaces is an outer circumferential surface of the protruding piece of the outer container and an inner circumferential surface of the joining side wall of the inner container,
2. The double container according to claim 1, wherein the other pair of said two pairs of opposing surfaces is said base end surface of said outer container and an end surface of said joining side wall of said inner container. The double container according to claim 2, which has an ultrasonic rib on the inner periphery of the base end surface of the outer container. The double container according to claim 2, wherein at least one of the pair of opposing surfaces consisting of the base end surface of the outer container and the end surface of the joining side wall of the inner container is a fixed surface. The double container according to claim 2, wherein of the two pairs of opposing surfaces, a pair of surfaces along the joining direction of the outer container and the inner container are formed as opposing inclined surfaces. The double container according to claim 2, wherein of the two pairs of opposing surfaces, a pair of surfaces along the joining direction of the outer container and the inner container are each formed as an uneven surface. The double container according to claim 2, wherein the intersection of the end face of the joining side wall and the inner peripheral surface of the inner container is formed as a chamfered portion. The double container according to claim 2, wherein the intersection of the base end surface of the outer container and the outer peripheral surface of the protruding piece is formed as a recess with a cross section that is L-shaped. A method for joining a double container in which both side walls of an outer container having an outer wall and an inner container having a joining side wall are joined, comprising the steps of:
The outer wall and the joining side wall are engaged with each other at two pairs of opposing surfaces,
A method for joining double containers, in which at least one of the two pairs of opposing surfaces, which are perpendicular to the joining direction of the outer container and the inner container, is joined together by ultrasonic welding to form a joining surface. The outer container has a protruding piece formed at an end of the outer wall, the protruding piece protruding from a base end surface,
10. The method for joining a double container according to claim 9, wherein an ultrasonic rib is provided on the inner peripheral side of the base end face, and at least the base end face and the end face of the joining side wall of the inner container are joined by ultrasonic welding to form a joining surface. The method for joining a double container according to claim 9, wherein the two pairs of opposing surfaces are bonded to each other by ultrasonic welding to form a bonding surface.

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