JPH1081364A - Composite container - Google Patents

Abstract

PROBLEM TO BE SOLVED: To ensure excellent strength against the drop impact by realizing the polygon not less than pentagon in the horizontal section of a body part of a bottleshaped container in a composite container where the plastic bottle- shaped container is integrated with an outer container mainly comprising paper of the structure to cover at least the body part of the bottle-shaped container. SOLUTION: The adhesive is applied to an inner surface of paper, e.g. the coated cardboard in which polyethylene is extrusion-laminated, and a cylindrical carton 1 regular hexagonal in horizontal section is manufactured, and a pre-form is manufactured as an inner container 2 through injection molding of polypropylene. The pre-form is heated and arranged in the carton 1, biaxial stretch blow molding is performed, and the inner container 2 is adhered to the carton 1 to manufacture a desired composite container. The shape in the horizontal section of the body part 5 of the container is polygon not less than pentagon, or hexagon where every interior angle is not less than 108 deg. so that the interior angle of the inner container 2 is not an acute angle, preventing breakage when an impact caused by the drop is applied.

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, and granular contents.

[0002]

2. Description of the Related Art Conventionally, soft drinks, spirit drinks, juices,
Plastic bottles are widely used as containers for liquid seasonings, foodstuffs such as rice, and liquid detergents. However, in recent years, with increasing concern about environmental issues and resource depletion issues, containers that use less plastic are desired. As a countermeasure, a composite container (bag-in-box) in which a bag-like container with a plastic spout is accommodated inside a paper outer container is widely used. This container is lightweight and can be easily transported because it can be folded small when no contents are stored.In addition, the volume of the container can be reduced at the time of disposal, and paper and plastic are separated and disposed. It has such advantages as possible.

However, for example, in the manufacture of a bag-like container with a spout for a bag-in-box, an edge portion of a single-layer or multilayer film is bonded by heat sealing or the like, and then molded by injection molding or the like. There is a disadvantage that the number of manufacturing steps is large, for example, the spout must be joined by means such as welding. In terms of performance as well, the heat-sealed portion on the end face of the film and the welded portion between the spout and the bag-like container are inferior in impact resistance to other portions, and the bag may be broken by a drop impact.

Accordingly, a method has been proposed which solves the problems of the drop impact strength and the number of manufacturing steps by forming the inner container by blow molding. In this method, an outer container (carton) mainly composed of paper coated with an adhesive on an inner surface is placed in a blow molding die in advance, and a preform heated at a molding temperature is introduced therein. This is a method of manufacturing a composite container by integrating the outer container with the inner container made of blow-molded plastic by seamlessly by blow molding. When the container is discarded, paper and plastic can be separately discarded.

[0005] However, when the amount of plastic used is reduced to the utmost, the inner container of the composite container has a very thin container wall, and depending on the container shape, may have poor impact resistance. When the inner container is formed into a container shape by stretch blow molding inside the carton, the inner container shape transfers the surface shape inside the carton (= the inner container is formed into the same shape as the surface shape inside the carton). ). When the cross-sectional shape of the body of the carton is polygonal, the container wall thickness of the inner container becomes the thinnest at the vertex. When the body section of the carton is rectangular or smaller, the interior angle of at least one apex angle is 90 degrees or smaller. Since the inner container has a thinner container wall than conventional plastic containers, after filling the contents and dropping, the inner container's smallest apex angle part becomes extremely thin when dropped. As a result, the bag may be broken (hereinafter referred to as a notch effect), and the inner container may be broken and the contents may leak out, which may lose the function as the container and impair the commercial value. In order to eliminate the notch effect, the inner container having a circular horizontal cross-sectional shape seems to be the best, but when comparing the circular shape with the polygonal shape, the inner container having a circular horizontal cross-sectional shape is considered to be the outer container. (Carton) is difficult to produce, the shape is limited, and the carton is cylindrical.
Therefore, in order to cover the shoulder and the bottom of the inner container with the carton, the carton must be divided into multiple parts,
It is disadvantageous in manufacturing process, cost, and strength. On the other hand, in the case of a polygon, the carton can cover not only the body of the inner container but also the shoulder and the bottom with a single member, which is advantageous in terms of manufacturing process, cost and strength. Also, after fabrication,
Since it can be folded for transportation and storage, it does not take up space and is advantageous in terms of transportation and storage efficiency.

[0006]

In view of the above problems, the present invention has excellent strength against drop impact, can be easily manufactured with a small number of steps, and can be reduced in volume at the time of disposal. It is another object of the present invention to provide a composite container that can completely separate paper and plastic after use.

[0007]

SUMMARY OF THE INVENTION The present invention has been conceived in order to solve the above-mentioned problems, and the invention of claim 1 is directed to a plastic bottle-shaped container and a structure for covering at least the body of the bottle-shaped container. Wherein the horizontal section of the body of the bottle-shaped container is a polygon having five or more angles, wherein the outer container is made of a paper-based outer container.

[0008]

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, the present invention will be described in more detail. The outer container (carton) in the present invention is a cylindrical container mainly made of paper, and is formed so as to cover the bottom, the trunk, the shoulder, and the vicinity of the mouth of the composite container, and is integrated with the inner container. . Alternatively, the inner container can be seen at the bottom, the body, the vicinity of the mouth, and the like of the container. The shape of the inner container is a shape that can be obtained by stretch blow molding, and is a pentagon or more polygonal shape, and the shape of the outer container is a shape that matches the shape of the inner container.

The outer container is mainly made of paper, and the surface of the paper is used to print product information such as product names and precautionary notes, and image information such as pictures and photographs. And so on. An adhesive layer for connecting to the inner container is provided on the back surface, and an adhesive filler layer, a water-resistant layer, a gas barrier layer, a light-shielding layer, and the like are provided as necessary. Further, the paper itself can be impregnated with various functional materials.

Specific paper can be selected from a group of paper such as wrapping 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, a base paper for food containers in a 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 used as a material for the outer container, a method of processing a paper roll is stable, and uniform and economical production is possible. Specifically, the method is selected from extrusion lamination to paper by a T-die method, knee laminating, and dry lamination of a film to paper. There is also a method in which the film is pressure-bonded to paper by a roll or a flat plate hot press. The paper member impregnated with or laminated with various materials becomes an outer container through printing, punching, and backing processes.

When a rectangular shape is selected as the container shape, the outer container also has a polygonal shape. Until now, the mainstream of the polygonal shape was a square horizontal cross-sectional shape. In particular, the horizontal cross-sectional shape is often a square. When the horizontal cross-sectional shape of the outer container body is a square, the inside angle of each apex angle is 90 degrees. At this time, if the inner container is blow-molded in the outer container, the inner container transfers the shape of the outer container (= the inner container is formed into the same shape as the inner shape of the carton), so the horizontal cross-sectional shape of the body is square. Become. The position of the apex of the square is the farthest position from the center of the container, and the thickness of the container wall of the inner container is the thinnest at the apex. Accordingly, the apex angle of the body of the inner container has a thin container wall and an acute angle. As a result, very thin,
In addition, when the container is filled with a liquid having a higher bulk specific gravity than powder or the like at the body angle portion of the inner container having an acute angle and is dropped, the bag is broken from the body angle portion of the inner container. In any case, it is important not to make the angle of the trunk angle acute, as a method of preventing the bag from being broken from the trunk angle of the inner container.

[0013] As a method, first, the horizontal sectional shape of the container body is a polygon having five or more angles, and all the interior angles are each at least 108 degrees. Or, the horizontal cross-sectional shape of the container body is a hexagonal polygon, and all interior angles are each at least 108 degrees, or the horizontal cross-sectional shape of the container body is octagonal or more, and all interior angles are each at least 108 degrees. Or, the horizontal cross-sectional shape of the container body is to cut out the four vertices of a square with a straight line and make it an octagon. Further, the horizontal sectional shape of the container body is octagonal, and all the internal angles are each 135 degrees. More specifically, the horizontal cross-sectional shape of the container body is a polygon of five or more angles, and all interior angles are 108 degrees or more. When all the inner angles are equal to or more than 108 degrees, the inner angle of the inner container does not become an acute angle, and the bag is not broken even if an impact such as when the contents are filled and dropped is applied.

Depending on the size of the container, the weight of the contents, and the thickness of the inner container wall, it is expected that an impact angle of 108 degrees will result in insufficient impact strength. In such a case, the impact resistance is improved by setting the minimum inner angle to 135 degrees or more. If the minimum inner angle is not 135 degrees, it is necessary to make the container body horizontal cross-sectional shape a polygon having a larger number of angles. When the horizontal cross-sectional shape of the container body is a polygon with more corners, the horizontal cross-sectional shape of the container body approaches a circle. Therefore, the ratio of the thickness of the apex corner to the flat part of the container wall of the inner container body is reduced, and the apex corner is not significantly thinned, so that the impact resistance is not deteriorated.

As materials for the inner container, polyesters such as polyethylene terephthalate and polyethylene naphthalate, polyolefins 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 inner material, but a material having high transferability of the shape of the outer container at the time of stretch blow molding, processing conditions, or a container wall of the inner container is extremely thin. In such a case, the effect of the present invention becomes remarkable. In addition, by making the container body polygonal, the width of the container body flat portion can be reduced, and expansion (body swelling) of the container body when liquid content is filled can be prevented. Further, even with respect to deformation due to a pressure difference between the inside and outside of the container, such as deformation due to reduced pressure inside the container, the vertex of the polygon produces an effect like a rib, and deformation of the container can be prevented.

<Operation> When a composite container is produced by performing blow molding in the outer container having the above shape, the horizontal cross section of the body of the inner container has a polygonal shape of five or more angles, and the inner angle of the apex angle is at least 108 degrees. Further, the ratio of the thickness of the container wall at the apex angle to the thickness of the container wall at the flat portion becomes small. for that reason,
After filling the contents such as liquid, the bag is not broken even if dropped. In addition, the apex portion exerts a rib-like effect, and the width of the flat curved surface portion of the container body becomes smaller, so that the body swells when filling the contents and the deformation of the body due to the pressure difference between the inside and outside of the container. Is suppressed, and the shape of the container can be maintained.

[0018]

The present invention will be specifically described below with reference to examples, but the present invention is not limited to these examples.

Example 1 Polyethylene was extrusion-laminated on the inner surface of a coated cardboard of 310 g / m ^{2 as} a paper by a T-die, and an EVA (ethylene-vinyl acetate copolymer) adhesive was partially applied on the inner surface. This was applied to produce a cylindrical carton 1 having a regular hexagonal cross section. As the inner container, a preform having a weight of 15 g was prepared by injection molding polypropylene. The preform is heated by an infrared heater, placed inside the carton 1, and subjected to biaxial stretch blow molding to adhere the inner container 2 in which the body and the spout are integrally formed to the carton 1 so as to adhere to the contents. Amount 1000
A multi-ml composite container was made.

<Embodiment 2> The horizontal cross-sectional shape of the outer container is
A composite container similar to that of Example 1 was prepared except that a square having a side of 68 mm was an octagon formed by cutting off a vertex angle with a straight line having a length of 15 mm so that all the internal angles were 135 degrees.

<Comparative Example> A composite container similar to that of Example 1 was prepared except that the horizontal cross-sectional shape of the outer container was an equilateral triangle having a side length of 80 mm.

The impact strength of the containers produced in Examples 1 and 2 and Comparative Example was evaluated. The evaluation method was as follows: 1000 ml of water was filled in the composite container prepared above, stored at 5 ° C. for 24 hours, and dropped upright ten times from a height of 1 m onto concrete. If the water in the container leaks by dropping less than 10 times, the subsequent drop is not performed and the number of drops when the water leaks is recorded. Test the 10 containers and record the average of the number of breaks and the number of drops before the break of the broken container. Table 1 shows the results of the evaluation.

[0023]

[Table 1]

As shown in Table 1, in the comparative example in which the horizontal cross-sectional shape of the body was square, all ten containers broke at the body corner and broke with almost one drop. On the other hand, in Example 1, the number of damaged pieces was two, and the bag was not broken unless it was dropped eight or more times. Further, the swelling amounts of the containers prepared in Examples 1 and 2 and Comparative Example were evaluated. In the evaluation method, 1000 ml of water was filled in the composite container prepared as described above, and after storing at room temperature for 24 hours, the bulging amount at the center of the container body was measured. Table 2 shows the results of the evaluation.

[0025]

[Table 2]

As shown in Table 2, the swelling amount was 12 mm on average in the comparative example in which the horizontal cross section of the body was square.
On the other hand, in Example 1, the swelling amount was 5 mm, and in Example 2, the swelling amount was 4 mm, and the effect of suppressing body swelling was confirmed.

[0027]

According to the present invention, a composite container combining paper and plastic for storing liquid contents, powder contents, and granular contents has excellent strength against drop impact and requires a small number of steps. It can be easily manufactured, and the volume can be reduced at the time of disposal, the paper does not peel off during use, and the paper and the plastic can be separated after use. In addition, the use of the carton according to the present invention improves the impact resistance, makes it possible to further thin the container wall of the plastic inner container, reduces the weight of the inner container, and further reduces the amount of plastic used. Can be provided, and a more environmentally friendly container can be provided.

[Brief description of the drawings]

FIG. 1 is a perspective view of an embodiment of the composite container of the present invention.

FIG. 2 is a conceptual diagram showing a horizontal cross-sectional shape of an outer container according to a first embodiment of the composite container of the present invention.

FIG. 3 is a conceptual diagram showing a horizontal cross-sectional shape of an outer container according to a second embodiment of the composite container of the present invention.

[Explanation of symbols]

 1: Carton 2: Inner container 3: Mouth 4: Shoulder 5: Trunk 6: Apex angle 7: Interior angle of apex angle

 ────────────────────────────────────────────────── ─── Continuing on the front page (72) Inventor Hideo Fukushima 1-5-1, Taito, Taito-ku, Tokyo Toppan Printing Co., Ltd. (72) Inventor Naoshi Umezu 1-15-1 Taito, Taito-ku, Tokyo Letterpress Printing Co., Ltd.

Claims (1)

[Claims] 1. A composite container in which a plastic bottle-shaped container and an outer container mainly made of paper having a structure that covers at least the body of the bottle-shaped container are integrally connected to each other. A composite container having a polygonal cross section of five or more angles.