JPH09221139A - Water-resistant composite container and its production method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To increase the water-resistance of an exterior container of a composite container provided with both preserving aptitude for the contents and disposability after use, by processing the exposed end face of the exterior material composed of a rigid material chiefly made of paper with a water-resistant treatment. SOLUTION: This water-resistant composite container 1 is constituted of a cylindrical exterior material 2, a plastic interior container 3 contained in the exterior material 2. The mouth 4, the shoulder 5, the body 6, and the bottom 7 are integrally formed by the stretch blow molding, in the interior container 3. Polyethylene sheets are laminated at both faces and a cardboard processed in the water-resistant treatment is formed cylindrical to make the exterior material 2. Further, the end face of the exterior material is processed in the waterresistant treatment and the opening 8 in the vertical direction is bent inward and fixed. In this way, when the container is preserved in water, this structure prevents the penetration of water from the end face of the exterior material and also the delamination of the endface and the deterioration of the joint strength.

Description

Detailed Description of the Invention

[0001]

The present invention relates to beverages, especially beer,
The present invention relates to a composite container with excellent pressure resistance suitable for filling and packaging carbonated drinks, and in particular, a water-resistant composite container made of paper and plastic suitable for cooling and storing in ice water or water and its production. Is the way.

[0002]

2. Description of the Related Art Beverages containing carbonic acid such as beer are conventionally sold in glass bottles and metal cans. These containers have advantages such as excellent oxygen barrier properties and carbon dioxide gas barrier properties, excellent pressure resistance, and little adsorption of the content itself or the flavor component of the content, etc. However, there is a problem that the waste after use cannot be treated as general waste.

Although glass bottles can be used repeatedly, they are likely to be damaged by being dropped or the like, are heavy, and it is difficult to purchase a large quantity of products at one time. There's a problem.

Further, metal cans represented by steel cans and aluminum cans are not damaged by being dropped or the like and are light in weight, so that they are highly used in vending machines and are becoming more popular. After using this metal can, it is collected as separated waste and partially recycled, but its recovery rate is still low. In addition, since it is easy to use, it is used and discarded in large quantities in tourist spots and tourist resorts, and its collection and disposal has become a major social problem.

Further, in addition to the glass bottle and the metal can, a hollow container made of polyethylene terephthalate (hereinafter abbreviated as PET) is used because of its advantages such as transparency, light weight and safety. It has been put on the market for various uses as a container.

The PET container has the advantages as mentioned above, but has a light-shielding property, an oxygen barrier property, and a light-shielding property as compared with glass bottles and metal cans.
Since the carbon dioxide gas barrier property, the water vapor barrier property, and the like are inferior, a color tone change such as decolorization or discoloration occurs depending on the content, or the quality is changed. In particular, as a container for carbonated drinks, carbon dioxide gas in the content liquid may be released, so that it is not suitable for long-term storage. Further, although some PET containers have been collected, it is difficult to dispose of them after use like the above-mentioned metal can, which has become a big problem in recent years.

On the other hand, a paper container is a container that is relatively easy to process after use, but is currently not used except for some beverages (milk, juice, etc.) having a short shelf life. In particular, it has not yet been used in beverages such as beer whose content liquid contains carbon dioxide.

In recent years, a composite container in which a plastic bag-like container with a spout is housed inside a paper outer container called a bag-in-box has been available.
This container does not take gas barrier properties into consideration, has insufficient strength, and has a problem that the number of manufacturing steps is large.

As described above, each of the currently popular containers does not satisfy both the storage suitability of the contents and the easy disposal after use, and various improvements are required.

Therefore, in recent years, a composite container in which a paper container is combined as an outer container and a plastic container is combined as an inner container has been proposed. In this composite container, the body of the inner container is thinly formed, and a rigid paper outer container having a barrier property is integrated with the body. The outer container retains the pressure resistance and the barrier property to prevent the container from being deformed and the carbon dioxide gas from being dissipated due to the internal pressure of the carbonated drink, beer or the like.

Further, after use, the body of the inner container is thin so that it can be deformed to easily separate it from the outer container, and the plastic and the paper can be separated and discarded. Furthermore, if the amount of plastic used is made smaller than the total weight of the container,
It can be treated as general waste without separating the container.

However, when the above-mentioned composite container is put in ice water or water to be cooled or stored, since the end face of the paper-made outer container is exposed, water permeates from the end face to the inside of the paper phase, and the paper is intercalated. There is a problem of peeling off. Further, when the outer container is a tubular body having a joint portion (bonding portion), the strength of the joint portion is reduced and the joint portion is peeled off due to the pressure of the contents. This causes a problem that the appearance of the container is significantly deteriorated and the commercial value is lowered.

Therefore, in order to solve the above-mentioned problems, the present invention provides a composite container which satisfies both the storage suitability of contents and the easy disposal after use, so that the outer container has water resistance. An object is to provide an improved composite container and a method for manufacturing the same.

[0013]

The present invention has been conceived in order to solve the above-mentioned problems, and the invention of claim 1 is thicker than other parts of the plastic inner container. A composite container in which an outer packaging material made of paper or a material having a rigidity mainly composed of paper is integrally provided on the surface of a thin portion, characterized in that an exposed end surface of the outer packaging material is subjected to a water resistance treatment. It is a water resistant composite container. The invention according to claim 2 is the water resistant composite container according to claim 1, wherein the exterior material is a tubular body having an upper and lower opening. The invention of claim 3 is characterized in that the exterior material is a bottomed cylindrical body.
It is the water-resistant composite container described. The invention of claim 4 is the water resistant composite container according to any one of claims 1 to 3, wherein the exposed end surface of the opening of the exterior material is folded back and fixed inward of the exterior material. According to a fifth aspect of the present invention, the exposed end surface of the exterior material opening is skived at approximately half the thickness, and the skived portion is folded back and fixed inward of the exterior material. 3. The water resistant composite container according to any one of 3 above. The invention according to claim 6 is the water resistant composite container according to any one of claims 1 to 3, wherein the exposed end surface of the exterior material opening is covered with a water resistant tape-shaped member. The invention of claim 7 is the water resistant composite container according to any one of claims 1 to 3, wherein the exposed end surface of the exterior material opening is impregnated with a water resistant agent. According to the invention of claim 8, an exterior material molded into a predetermined shape is placed in advance in a blow molding die, a preformed body of a plastic inner container is inserted into the exterior material, and stretch blow molding is performed. 8. The method for producing a water resistant composite container according to claim 1, wherein the inner container and the outer casing are integrated at the same time as the molding of the inner container.

[0014]

BEST MODE FOR CARRYING OUT THE INVENTION The present invention will be described in detail below with reference to the drawings, taking as an example the case where the container is cylindrical. First, as shown in FIG. 1, a water-resistant composite container 1 of the present invention comprises a tubular exterior material 2 mainly composed of a cylindrical paper.
And an inner container 3 made of plastic contained in the exterior material 2. The inner container 3 has a mouth portion 4, a shoulder portion 5,
The body portion 6 and the bottom portion 7 are integrally formed by stretch blow molding. The bottom portion 7 has a shape that bulges downward in a spherical shape and has a structure capable of withstanding the pressure of the contents, and the self-supporting property of the pressure resistant container 1 is ensured by the exterior material 2. The exterior material 2 may have a shape that also covers the shoulder portion 5 of the interior container 3.

The exterior material 2 is made by processing water-resistant paperboard, which has polyethylene laminated on both sides, into a tubular shape. The paperboard may be waterproofed by any method such as extrusion coating of polyolefin, lamination, impregnation with parefin wax, or the like, and it is desirable that the paper member has a structure in which water does not permeate. Further, the exterior material 2 is generally fixed to the thin body of the interior container 3,
Since the internal pressure of the contents is received, the basis weight 2 has excellent mechanical strength.
It is necessary to use paperboard of 00 g / cm ² or more.

The end surface of the exterior material 2 is subjected to an end surface treatment, and as shown in FIG. 1, the end surface 8 of the vertical opening of the exterior material 2 is bent and fixed inward (toward the inner container). Further, FIG. 3 shows a cross-sectional view of the end surface 8 ′ of the bonding portion 9 of the exterior material 2.
For the end face 8 ', the exposed end face is skived about half of its thickness, and the skived portion is folded back inside the exterior material 2.
The structure is such that the end face is not exposed to the outside so that the folded portion is fixed to the outside of the exterior material 2 and is fixed. Of course, this structure may be adopted for the end surface 8 of the vertical opening of the exterior material 2. These prevent water permeation from the end surface of the exterior material when the container is stored in water, and prevent delamination of the end surface and deterioration of the strength of the joint. In addition, there are various methods such as gassho type and tape pasting type using plastic tape as the end surface treatment of the exterior material.
The treatment may be performed using any method. FIG.
As shown in, the bottom plate 10 may be caulked in the opening below the tubular body 6 having an open top and bottom to form a bottomed tubular exterior material 2 '.

The water resistant composite container of the present invention is required to have a barrier property so that carbonated beverages, beer and the like can be filled and packaged. When the exterior material is a member obtained by simply applying water resistance treatment to paperboard, the paper has poor barrier properties against gases such as oxygen and water vapor, and it is necessary to impart barrier properties by various methods.

For example, a paper obtained by laminating a barrier film on paper is used. As such a barrier film, use is made of a resin single layer film having excellent barrier properties, a multilayer film, a film coated with a resin having excellent barrier properties on the surface, or a film having a thin film of a barrier material provided on the surface. You can

As the resin excellent in oxygen barrier property, saponified ethylene-vinyl acetate copolymer, polyamide resin, high nitrile resin, polyvinylidene chloride resin and the like can be used. As a material having excellent water vapor barrier properties, an amorphous resin obtained by copolymerizing a cyclic olefin and ethylene can be used.

Examples of the barrier material used for the film having a thin barrier material film on its surface include metal oxides such as silicon oxide, magnesium oxide and aluminum oxide. Also, as the film, PET, polypropylene,
Nylon or the like is used. A film provided with a thin film of a metal oxide has excellent oxygen and water vapor barrier properties and is particularly preferable. The thin film layer is formed by vapor deposition or coating, and its thickness is preferably 100 to 3000 Å.

The plastic material forming the inner container of the present invention may be any blow-moldable or stretch blow-moldable thermoplastic plastic, such as polyethylene terephthalate (PET) or polyacrylonitrile (PA).
N), polyethylene naphthalate (PEN), polypropylene (PP), ethylene vinyl alcohol copolymer (EVOH), polyamide resin (PA), or a blend or laminate of these resins may be used.

In addition, it is desirable to use a degradable polymer in the plastic portion of the inner container and the outer material in order to make disposal after use easier. As the degradable polymer, a microbial degradable polymer that can be used as a polylactic acid type, an aliphatic polyester type, a hydroxy polyester type, etc., and then buried in the soil and decomposed as it is is desirable.

Next, a method of manufacturing the inner container and the outer material of the pressure resistant container of the present invention will be described. One is a method in which the inner container and the outer material are separately processed and integrated. At this time, even if the inner container and the outer material are integrated by fitting,
They may be integrated via an adhesive. In consideration of easy disposal, it is preferable to use an alkaline solution or an adhesive that can be dissolved in warm water as an adhesive in order to easily separate the inner container and the outer material.

Further, the adhesive strength can be controlled by the kind of adhesive and the coating amount of the adhesive layer, and the coating amount of EVA is 6 g / m 2.
² or less, PO system 10 g / m ² or less,
The inner container and the outer material can be separated.

Stretch blow molding will be described as another example of the manufacturing method. First, a preform made of plastic is obtained in advance by injection molding. A pressure-resistant container can be obtained at the same time as molding by placing an exterior material molded in a predetermined shape in a mold, and performing stretch blow molding of a preformed body of the inner container heated to the molding temperature in the exterior material. .

When the water resistant composite container of the present invention is obtained by placing it on a mold, it is desirable to provide an adhesive layer on the inner surface of the exterior material, which exhibits an adhesive effect at the molding temperature of the preform for the inner container. . According to the present invention, since the end of the exterior material is subjected to the water resistance treatment, when the container is immersed in ice water or water for cooling the contents in the summer, the end does not swell due to water and delamination can be prevented. Since the exterior material has water resistance, it does not swell or float even when it is stored in water for a long time or gets wet with the contents, and since the strength is maintained, deformation due to the internal pressure of the container can be prevented. Therefore, there is little change in the outer appearance of the container even under water, a humid atmosphere, dew condensation, etc., and the commercial value is not impaired for a long period of time.

The present invention will be described in more detail based on the following examples.

[0028]

【Example】

(Example 1) Two-sided polyethylene-coated basis weight 250
As shown in Fig. 1, a g / m ² manila cardboard is cross-sectioned by bending the upper and lower ends at the end, and laminating the bonded part at the cross section, and an EVA system with a coating amount of 3 g / m ^{2 on} the inner surface. An adhesive was applied to produce a tubular exterior material. This exterior material is placed in the mold in advance, and PET (intrinsic viscosity 0.78 g /
The preformed body injection-molded using dl) was blow-molded at a temperature suitable for stretching to form a water resistant composite container having an inner volume of 350 ml.

(Example 2) As a facet treatment, a double-sided polyethylene-coated Manila cardboard having a basis weight of 250 g / m ² was coated with a tape having a polyethylene / polyester / polyethylene structure on the end face thereof. A water-resistant composite container having an inner volume of 350 ml was molded by the same method as described above.

(Comparative Example 1) In the same manner as in Example 1, except that the end surface treatment was not carried out, 350 m
1 l of composite container was molded.

Comparative Example 2 A composite container was molded in the same manner as in Example 1 except that the polyethylene coat was not subjected to water resistance treatment and end face treatment was not performed.

The composite containers of Examples 1 and 2 and Comparative Examples 1 and 2 were immersed in water for 24 hours. Table 1 shows the tensile strengths of the exterior material-bonded portion before and after the immersion. In the measurement, the inner container was separated and the strength of only the exterior material was used.

[0033]

[Table 1]

In Comparative Example 1 and Comparative Example 2, when immersed in water, the strength of the bonded portion was remarkably reduced, and it was judged that the strength was insufficient for filling the contents with internal pressure.

The containers of Examples 1 and 2 and the containers of Comparative Examples 1 and 2 were filled with 330 ml of carbonated water having a carbon dioxide gas concentration of 3.3 gas volume, the containers were stored in water, and the appearance was observed. . The results after 1 week are shown in Table 2.

[0036]

[Table 2]

In Examples 1 and 2, there is no change in appearance even after being stored for 1 week, and in Comparative Examples 1 and 2, it is shown that the exterior material is peeled between the layers or separated and has no commercial value. Was done.

[0038]

Since the water resistant composite container of the present invention is further subjected to a water resistant treatment on the exterior material, it can be stored in water or in a place of high humidity, and can be handled like a conventional can or glass bottle.
In addition, since the exterior material is mainly paper, it has good printability, can print tones, and is excellent in store effect.

Further, the water resistant composite container of the present invention is an exterior material made of paper or a material having a rigidity mainly composed of paper on the surface of a portion having a thinner wall thickness than other portions of the plastic inner container. Since the structure is integrally provided, the strength against the internal pressure can be supplemented by the exterior material, and the amount of resin used in the inner container can be reduced as compared with a plastic container having the same capacity.

Further, by devising the method of integrating the inner container and the outer material, the container can be separated after use and discarded, and it is also an environment-friendly container.

Further, in the water resistant composite container of the present invention, the molded exterior material is placed in the molding die of the inner container, and the integrated container is manufactured simultaneously with the molding of the inner container, so that the process is simple. It leads to cost reduction.

[Brief description of drawings]

FIG. 1 is an explanatory view seen from a side of an embodiment of a pressure resistant container of the present invention.

FIG. 2 is a side view of another embodiment of the pressure resistant container of the present invention.

FIG. 3 is a cross-sectional view showing an embodiment of the method for treating the end surface of the pressure-resistant container of the present invention.

[Explanation of symbols]

1 ... Water resistant composite container 2, 2 '... Exterior material
3 ... Interior container 4 ... Mouth 5 ... Shoulder 6 ... Body 7
・ ・ ・ Bottom part 8 ・ ・ ・ End face 9 ・ ・ ・ Laminating part

 ─────────────────────────────────────────────────── ─── Continued Front Page (72) Inventor Keiko Nakamura 1-5-1 Taito, Taito-ku, Tokyo Toppan Printing Co., Ltd.

Claims (8)

[Claims] 1. A composite container in which paper or an exterior material made of a material having a rigidity mainly composed of paper is integrally provided on the surface of a portion having a thinner wall thickness than other portions of the plastic inner container. The water resistant composite container is characterized in that the exposed end surface of the exterior material is treated to be water resistant. 2. The water resistant composite container according to claim 1, wherein the exterior body is a tubular body having an upper and lower opening. 3. The water resistant composite container according to claim 1, wherein the exterior body is a bottomed tubular body. 4. The water resistant composite container according to claim 1, wherein the exposed end surface of the exterior material opening is folded back and fixed inward of the exterior material. 5. The exposed end face of the exterior material opening is skived at approximately half the thickness thereof, and the skived portion is folded back and fixed inward of the exterior material. Item 5. The water resistant composite container according to any one of items 3. 6. The water resistant composite container according to claim 1, wherein the exposed end surface of the exterior material opening is covered with a water resistant tape-shaped member. 7. The water resistant composite container according to claim 1, wherein the exposed end surface of the exterior material opening is impregnated with a water resistant agent. 8. An interior is prepared by placing an exterior material, which has been molded into a predetermined shape, in a blow molding die, inserting a preform of a plastic interior container into the exterior material, and performing stretch blow molding. The method for manufacturing a water resistant composite container according to claim 1, wherein the container is integrated with the exterior material simultaneously with molding of the container.