JPH10305870A - Compound container - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a compound container which is friendly to the environment by making it possible to completely separate paper from plastic and to reduce volume in disposing, which has high product value without the swelling or deformation of the container body after contents are filled and without deformation when the container is formed or in the environment the container is stored as to the compound container whose outside container mainly made of paper and whose inside container placed in the inside of the outside container and made of plastic are integrally joined by blow molding. SOLUTION: This compound container comprises an outside container 20 whose container body part 4 is provided with an inner member 30 having an uneven shape, and an inside container 10 having a shape matching the uneven shape of the inner member 30. The uneven shape of the inner member 30 has a longitudinal wave shape cross section when the container is seen from its top or bottom or has a transverse wave shape cross section when seen horizontally.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a composite container combining paper and plastic for storing liquid contents, powder contents, viscous contents and the like. The present invention relates to a configuration of a composite container that prevents deformation.

[0002]

2. Description of the Related Art Conventionally, as containers for storing various beverages, seasonings, liquid detergents and the like, polypropylene resin (P) has been used.
Plastic containers such as P), polyethylene terephthalate resin (PET), and polyvinyl chloride resin (PVC) are widely used.

[0003] However, in recent years, the increase in waste has become a major social problem, and in addition to the problem of resource conservation and energy and resource conservation, it has become a global environmental problem. I have. As a countermeasure, a composite container (back-in-box) in which a plastic bag with a spout is housed inside a paper outer container is widely used. This container is lightweight and can be transported easily because it can be folded small when no contents are stored.In addition, the container can be reduced in volume at the time of disposal, and paper and plastic can be easily separated. This is an environmentally friendly (ecological) composite container that can be recycled individually.

However, in the case of the above-mentioned composite container (back-in-box), for example, in the production of a bag-like container with a spout, the edge portion of a single-layer or multilayer film is bonded by heat sealing or the like, and then injection-molded thereto. However, there is a disadvantage that the number of manufacturing steps is large, for example, the spout formed by the above method must be joined by means such as fusion. In addition, in terms of performance, the heat-sealed part of the film end face and the fusion part of the spout are inferior in impact resistance compared to the part outside the fusion part, and there is also a problem that the bag may break due to a drop impact. is there.

Therefore, various methods have been proposed for solving the problems of the drop impact strength and the number of manufacturing steps by forming the inner container by blow molding (Japanese Patent Application No. 6-212538). This method uses an outer container (carton) mainly composed of paper with an adhesive or the like applied to the inner surface in advance.
Is placed in a blow mold, a preform heated at a molding temperature is inserted into the mold, and blow molding is performed to form an outer container (2) mainly composed of paper as shown in FIG.
0) and a plastic inner container (10) integrally and seamlessly formed by blow molding to form a composite container.

[0006] This container saves petroleum resources by making the plastic inner container (10) ultra-thin, and can be easily crushed at the time of disposal (reduced volume of waste). Environmentally friendly (ecological) that facilitates the separation of waste and allows each to be recycled
It is a composite container.

However, when the amount of plastic used in the inner container (10) is reduced to the utmost, the inner container (10) of the composite container has a very thin container wall, and depending on the shape of the container, the container may be filled after the contents are filled. There is a problem that the shape is deformed. In addition, when the members constituting the outer container (20) have low mechanical strength, there is a problem that when the contents are filled, swelling occurs in the container body (4).

Further, the outer container (20) and the inner container (1)
0) are paper and plastic, and are made of different materials, so that the ratio of expansion or contraction between the outer container (20) and the inner container (10) differs due to changes in temperature and humidity in the environment where the container is stored. . Therefore, when the outer container (20) and the inner container (10) are partially joined, there is a problem that stress is generated in the container and the container is deformed.

Further, when the plastic inner container (10) is molded by blow molding inside the outer container (20), the inner container (10) is formed by a blow mold after forming the container shape. Even after discharge, shrinkage due to temperature drop and deformation due to stress relaxation occur.

[0010]

SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned problems of the prior art, and it is an object of the present invention to provide a paper-made outer container (20) inside a plastic inner container. In a composite container in which the container (10) is integrally joined by blow molding, the container has high commercial value without deformation during container formation or in a container storage environment, and without bulging of the container body after filling the contents. It is an object of the present invention to provide a recyclable composite container that can reduce the volume at the time of disposal and completely separate and separate paper and plastic.

[0011]

In order to achieve the above-mentioned object, according to the present invention, a plastic inner container (10) is provided inside a paper-based outer container (20). ), Wherein an inner surface member (30) having an uneven shape is applied to a part of the inner surface of the outer container (20), and the inner container (10) is formed of the inner member. (30) A composite container having a shape corresponding to the uneven shape of (30).

In the invention according to claim 2, the inner container (30) of the outer container (20) is provided in the container body (4).

According to a third aspect of the present invention, there is provided the composite container, wherein the concave and convex shape of the inner surface member (30) has a longitudinal wave-shaped cross section with respect to the vertical direction of the container.

According to a fourth aspect of the present invention, there is provided the composite container, wherein the concave-convex shape of the inner surface member (30) has a transverse wave-shaped cross section with respect to the horizontal direction of the container.

[0015]

Embodiments of the present invention will be described below. As shown in FIG. 1A, the composite container of the present invention is a composite container in which a plastic inner container (10) is integrally joined to a paper-based outer container (20) by blow molding. A part of the inner surface of the outer container (20) is provided with an inner member (30) having an uneven shape,
The inner container (10) has a shape corresponding to the concavo-convex shape of the inner member (30).

According to the second aspect of the present invention, as shown in FIG. 1B, the inner surface member (30) of the outer container (20) is provided.
Is applied to the container body (4), that is, it is not applied to the shoulder (6) and the bottom (8).

First, the structure of the outer container (20) will be described in more detail. As shown in FIG.
The outer laminated resin layer (20b) is applied to the outer surface of (a), and the inner laminated resin layer (20c) is applied to the inner surface. Generally, an adhesive layer (3) for joining the outer container (20) and the inner container (10) is applied on the inner laminated resin layer (2). Outer laminate resin layer (20b)
Protects the outer printing surface of the outer container (20),
It may not be necessary depending on the use of the container. The inner laminate resin layer (20c) is used as an adhesive filler layer, a water-resistant layer, a gas barrier layer, a light-shielding layer, and the like as necessary. The paper itself is impregnated with various functional materials. Is also possible.

Therefore, the composite container of the present invention is shown in FIG.
As shown in (1), an inner surface member (30) having an uneven shape is provided on the adhesive layer (3) in the container body (4), and is joined to the outer container (20) by the adhesive layer (3). Further, an inner container (10) made of plastic is provided on the inner side by blow molding, and the outer container (20) is formed by an adhesive layer (3) applied to the container shoulder (6) and the bottom (8). )
Is to be joined. At this time, the shape of the portion of the inner container (10) in contact with the inner member (30), that is, the shape of the inner container (10) in the container body (4) corresponds to the uneven shape of the inner member (30). Things.

In the structure of the inner member (30), similarly to the outer container (20), an inner laminate resin layer as a filler layer, a water resistant layer, a gas barrier layer, a light shielding layer, etc. is provided on the inner surface of the paper layer. The outer laminate resin layer may be required depending on the use of the container.

The paper layer (20a) of the outer container (20) and the inner surface member (30) can be selected from a group of paper such as packaging paper, hybrid paper, and paperboard for paper containers. Here, as the wrapping paper, unbleached wrapping paper and bleached wrapping paper can be used. Further, as the hybrid paper, food container base paper in processed base paper is particularly preferable. In addition, as the paperboard for paper containers, manila balls, white balls, yellow paperboard, chip balls, colored paperboards and the like can be used. In addition to the above, functional paper such as water-resistant paper is used.

Further, these papers may be used alone or may be used by laminating with aluminum foil or polyester film.

As a method for producing a paper member from which the outer container (20) and the inner surface member (30) are formed, by processing a paper roll, it is possible to produce the material stably, uniformly and economically. is there. Specifically, the method is selected from extrusion lamination on paper by a T-die method, knee lamination, or dry lamination of a film on paper. There is also a method in which the film is pressed against the paper by a roll or a flat plate hot press.

As the method for forming the uneven shape on the inner surface member (30), embossing using a flat base, winding method using a step roll, and the like can be selected, but the method for forming a desired shape is as follows. The present invention is not limited to this, and can be arbitrarily selected.

An inner surface member (30) having an uneven shape.
And a gap (F) is partially generated between the outer container (20) and the outer container (20). The space (F) may be filled with a filler or the like. For the purpose of preventing the gap (F) from being lost due to the blow pressure when performing blow molding in the outer container (20), as described above, the gap (F) is filled with a filler or the like. The material of the inner member (30) is made to have a structure with high mechanical strength, the unevenness of the inner member (30) is devised, or the inner member (30) and the outer container (20) are firmly bonded. It is necessary to combine these methods.

An inner member (3) is provided on the inner surface of the outer container (20).
The location where 0) is provided is not particularly limited, but is preferably a portion where deformation of the container occurs or a portion where the stress of the container can be reduced for the purpose of preventing deformation of the container. More specifically, it is a portion that is smooth over a wide area, and in the case of a general container shape, this corresponds to the container body (4). In addition, it is also possible to provide the inner surface member (30) in other parts as a supplement. Inner surface member (30)
The outer shape, size, number, etc. of the container are not limited as long as the purpose of preventing deformation of the container can be achieved, but are preferably as small as possible.

The unevenness of the inner surface member (30) can be considered as streak-like unevenness or net-like unevenness. Regardless of the uneven shape, the cross-sectional shape must not have an acute angle and the height difference between the unevenness must not be large. With the acute-angled irregular shape, when the inner container (10) transfers its shape during blow molding, the inner container (10) has an acute-angled shape. There is a risk that the bag will break. Also, if there is a large difference in elevation in the uneven shape, the thickness of the container wall of the inner container (10) becomes uneven, and a thin portion is formed on the container wall. In addition, the thin portion of the container wall may break the bag. For the same reason, it is desirable to avoid a step. The allowable angle of these acute angles and the allowable height of the unevenness depend on the size, capacity, shape, etc. of the composite container, as well as the material and strength of the outer container (20). As described above, it is desirable that the uneven shape of the inner surface member (30) has a gentle curve in cross section.

When a rectangular shape is selected as the container shape, the outer container (20) has a polygonal shape. The body (4) of the outer container (20) shows a rectangular polyhedron. The rectangle has a flat part on which the inner surface member (30) can be provided.

As the material of the inner container (10), polyester such as polyethylene terephthalate and polyethylene naphthalate, polyolefin such as polyethylene and polypropylene, polystyrene, polyvinyl chloride,
Polycarbonate, polyamide, high nitrile resin and the like can be used. Preferably, use of polypropylene, polyethylene terephthalate, or polyethylene naphthalate is desirable. Further, the material of these inner containers may be a single layer or a multilayer structure.

As described above, various plastic materials can be selected as the material of the inner container (10), but the shape of the inner member (30) applied to the inner surface of the outer container (20) during stretch blow molding. The effect of the present invention is remarkable when the material having high transferability, the processing conditions, or the container wall of the inner container (10) is very thin.

Further, as a material for the inner container (10),
This is also effective when a material having a large difference in shrinkage ratio from the outer container (20) member is used, or when shrinkage becomes large due to insufficient cooling during blow molding. The outer container (20) is placed in a blow mold, a preform heated at a molding temperature is introduced therein, and blow molding is performed to integrate the outer container (20) and the inner container (10). When the composite container is removed from the mold, the composite container is cooled from high temperature to room temperature. Inner container (10) and outer container (20)
When they are integrated, the temperature is higher than room temperature, and then when they are cooled down to room temperature, the shrinkage ratios of the outer container (20) mainly made of paper and the inner container (10) made of plastic are different. Generally, the outer container (20) has a higher shrinkage ratio than the outer container (20).
The inner container (10) is smaller than the outer container (2).
0) and the portion where the inner container (10) is bonded and the portion where the inner container (10) is not bonded have a large shrinkage of the inner container and both ends are bonded to the outer container (20). ) Will cause wrinkles and bulges on the outer surface.
However, the inner surface member (30) having an uneven shape in this portion
The uneven shape is also formed in the inner container (10) by providing. Therefore, the shrinkage of the inner container (10) is absorbed by extending the uneven shape of the inner container (10),
The apparent shrinkage is the same as that of the outer container (20), and the outer container (20) serving as the exterior is free from wrinkles and swelling.

When the composite container is stored, expansion and contraction of the inner container (10) and the outer container (20) occur due to changes in the storage environment, in particular, changes in temperature and humidity. By providing an inner surface member (30) having an uneven shape on the outer container (20), the inner container (1) is provided.
The difference between the displacement of the outer container (20) and the expansion and contraction of the outer container (20) is absorbed, and the deformation of the container can be minimized.

Further, when the container wall of the inner container (10) is made as thin as possible to be blow-molded, the inner container (10) may be deformed when filled with a liquid content, causing a swelling phenomenon. is there. Such a swelling phenomenon is not observed when the outer container (20) member is strong, but becomes remarkable when the outer container (20) member has low strength or is extremely thin. However, by providing the inner surface member (30) having an uneven shape on the outer container (20), the inner container (10) is formed with the uneven shape,
Deformation of the container can be suppressed. In addition, by devising the uneven shape, it is possible to suppress deformation of the container, to bias the deformation only to a specific portion, or to deform in a specific direction.

Next, the uneven shape of the inner surface member (30) will be described. According to the third aspect of the present invention, as shown in FIG. 2 (a), a vertical wavy shape having a wavy cross section in the longitudinal direction is used for a normal vertically long container. The present invention is characterized in that, as shown in FIG. 1 (a), the container has a transverse wave shape in which the cross section has a waveform in the horizontal direction. In this way, the vertical or horizontal corrugated shape formed in the inner container exhibits the same effect as when the rib (partition wall) is provided in the inner container, and suppresses the swelling of the inner container due to the filling of the contents. Can be prevented from being deformed. At this time, the effect of preventing the deformation of the container increases as the unevenness increases, that is, as the amplitude of the waveform of the cross-sectional shape increases. However, if the amplitude of the waveform is increased, the difference in the thickness of the container wall of the inner container (10) becomes large, and an extremely thin portion is formed. Therefore, it is necessary to set the uneven shape so that the thickness of the container wall does not become extremely thin. Thus, without providing the inner container (10) with the ribs (partitions), it is possible to have the same strength of the container as when the ribs are provided.

As described above, the inner surface member (3
When a composite container is produced by performing blow molding in the outer container (20) provided with 0), a portion having an uneven shape is formed in the inner container (10). This uneven shape alleviates the distortion of the container due to the difference in the contraction rate and the expansion rate between the outer container (20) and the inner container (10) made of different materials, and the deformation of the container in response to molding shrinkage and a change in environmental temperature. It can be prevented.

In addition, the deformation of the inner container (10) is prevented by improving the strength of the inner container (10) against deformation of the container caused when the contents are filled. In addition, the thickness of the container wall of the inner container (10) can be further reduced, and a composite container more harmony with the environment can be obtained.

[0036]

Next, the present invention will be described in detail with reference to examples.

<Embodiment 1> FIGS. 2A and 2B
As shown in the figure, the paper layer (20a) has a basis weight of 310 g / m2.
^The inner laminated resin layer (2
As 0c), polyethylene is extruded and laminated with a T-die, and an EVA-based adhesive is partially applied as an adhesive layer (3) on the inner surface thereof, and is punched into a cylindrical shape having a regular square cross section. The blank of (20) was used. In addition, as the inner surface member (30), a basis weight of 250 g is separately provided.
/ M ² , polyethylene was extruded from the inner surface of the coated cardboard with a T-die and laminated, and embossing was performed thereon, thereby forming a longitudinal wave-shaped uneven shape having a sine curve in cross section.

Subsequently, the inner surface member (3) is attached to a portion corresponding to the blank container body (4) of the outer container (20) prepared earlier.
No. 0) was adhered, and the tube was bent along the fold line of the blank to form an outer container (20). this is,
As shown in FIGS. 2A and 2B, the outer container (2
The container body (4) of (0) is a composite container provided with an inner surface member (30) having a vertical wavy shape in the vertical direction of the container. As the inner container (10), a preform having a weight of 15 g was prepared by injection molding polypropylene. This preform is heated by an infrared heater and placed inside the outer container (20), and is subjected to biaxial stretch blow molding, so that the inner container (10) in which the body and the spout are integrally formed is replaced with the outer container. A composite container having an internal capacity of 1000 ml was prepared by bonding to (20).

<Embodiment 2> FIGS. 1A and 1B
As shown in (1), the inner container (30) provided on the inner surface of the outer container (20) had a transverse wave shape with respect to the vertical direction of the container.

<Comparative Example 1> A composite container was prepared using the same material and method as in Example 1 using the outer container (20) having no inner surface member (30).

The blisters of the containers prepared in Examples 1 and 2 and Comparative Example 1 were evaluated. In the evaluation method, 1000 ml of water was filled in the composite container prepared above and stored at room temperature for 24 hours, and then the size of the center of the container body (4) was measured. Table 1 shows the evaluation results.

[0042]

[Table 1]

As shown in Table 1, in the composite container of Comparative Example 1 in which the inner member (30) was not provided on the inner surface of the outer container (20), a deformation of 10 mm or more was observed. On the other hand, in the composite container of Example 1 in which the inner surface member (30) has a longitudinal wavy cross-sectional shape with respect to the vertical direction of the container, the bulging amount of the body is 2 mm or less, and On the other hand, in the case of the composite container of Example 2 in which the cross-sectional shape was a transverse wave shape showing a waveform, the bulge amount of the trunk was 5 mm or less. As described above, in the case where the inner surface member (30) was provided on the inner surface of the outer container (20), the swelling was small, and the inner surface member (30) having a longitudinal wavy shape was smaller.

[0044]

As described above, the present invention has the following effects. That is, in a composite container in which a plastic inner container is integrally joined by blow molding inside a paper-based outer container, a part of the inner surface of the outer container is provided with an inner surface member having an uneven shape, Since the container is a composite container having a shape corresponding to the uneven shape of the inner surface member, there is no deformation at the time of forming the container or in the container storage environment, and there is no deformation of the container body after filling the contents. There is an effect that a composite container can be provided. Further, since the inner container can be made extremely thin, there is an effect that it is possible to provide a composite container which is in harmony with the environment, which is the original purpose of saving natural resources and reducing the volume at the time of disposal of the container.

In addition, by forming a part of the inner surface of the outer container as a container body, it is possible to provide an environment-friendly recyclable composite container in which paper and plastic can be completely separated and separated.

Further, since the concave and convex shape of the inner surface member is a transverse wave shape whose cross section shows a waveform in the left-right direction of the container, there is an effect of reducing the bulging of the container body, and the cross-sectional shape in the vertical direction of the container. Since it is a longitudinal wavy shape showing a waveform, it is possible to provide a composite container with less swelling of the container body.

[Brief description of the drawings]

FIG. 1 is an explanatory view of a composite container showing an embodiment of the present invention. FIG. 1 (a) is a perspective view of a composite container showing one embodiment. (B) is an enlarged view of a cross section including the shoulder.

FIG. 2 is an explanatory view of a composite container showing an embodiment of the present invention, and FIG. 2 (a) is a perspective view of a composite container showing another embodiment. (B) is the enlarged view which expressed the trunk | drum in the cross section.

FIG. 3 is a perspective view of a composite container according to the present invention.

[Explanation of symbols]

 1 composite container 3 adhesive layer 4 container body 6 container shoulder 8 container bottom 10 inner container 20 outer container 20a paper layer 20b outer laminate resin layer 20c ‥‥ Inner surface laminated resin layer 30 ‥‥ Inner surface member F ‥‥ Void

Continuing from the front page (72) Inventor Hideo Fukushima 1-5-1, Taito, Taito-ku, Tokyo Letterpress Printing Co., Ltd. (72) Inventor Kenichi Niimi 1-5-1, Taito, Taito-ku, Tokyo Letterpress printing Inside the corporation

Claims (4)

[Claims] 1. A composite container in which a plastic inner container is integrally joined by blow molding to the inside of an outer container mainly made of paper, wherein an inner surface member having an uneven shape is provided on a part of the inner surface of the outer container. Wherein the inner container has a shape corresponding to the uneven shape of the inner surface member. 2. The composite container according to claim 1, wherein the inner surface member of the outer container is provided in a container body. 3. The composite container according to claim 1, wherein the concave / convex shape of the inner surface member has a longitudinal wavy cross section in the vertical direction of the container. 4. The composite container according to claim 1, wherein the concave-convex shape of the inner surface member has a cross-sectional shape in a horizontal direction of the container.