JPH10218170A - Paper container for liquid - Google Patents

Abstract

PROBLEM TO BE SOLVED: To easily separate a laminate body constituting a paper container into a layer chiefly made of paper and another layer chiefly made of plastic to facilitate waste disposal or reuse of resources. SOLUTION: This container is a gable-top type or the like constituted of a laminate body of a thermoplastic resin layer 1, a paper layer 2, a water-soluble resin layer 3, an adhesive resin layer 4, a gas barrier layer 5, and a thermoplastic resin layer 6 in the order from the external face. And the heat-adhesion part of mutual outside faces of the bottom-forming plate and the top-forming plate is made easily peelable and collapsible. And the laminate body is made easily separable to a layer chiefly made of paper and another layer chiefly made of plastics by immersing it into water.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a liquor, a wine, a coffee, etc., in which a laminate constituting a container can be easily separated between layers with water to facilitate disposal and reuse of resources. The present invention relates to a liquid paper container used for packaging.

[0002]

2. Description of the Related Art In recent years, environmental protection has been avoided, and the reuse of packaging materials has become a hot topic. A paper container for milk packaging consisting of a polyethylene / paper / polyethylene laminate has also been used in a gobel-top type paper container. For example, recycling activities have been conducted and resources have been effectively reused. However, goebel top paper containers used for packaging of sake, wine, coffee, etc., protect the contents,
In order to prolong the distribution means and the distribution period, it is necessary to provide a paper container having excellent gas barrier properties, and a laminate in which the gas barrier layer is laminated on the content side of the paper layer, for example, polyethylene / paper / adhesion A laminate composed of a conductive resin / aluminum foil / adhesive / polyethylene terephthalate / polyethylene is generally used. In a paper container made of a laminate having the above-described configuration, the aluminum foil is included in the laminate, and the ratio of plastic in the laminate is high, which makes it difficult to recycle a used gobel-top type paper container. In addition, there is a problem that the collection efficiency is low. In addition, since the paper container is formed of a very rigid laminate like the laminate having the above-described configuration, the top and bottom of the Goebel top type paper container are separated from each other by peeling off and bonding the outer adhesive portions. However, there is a problem that it is extremely difficult to reduce the bulk of the paper container.

[0003]

SUMMARY OF THE INVENTION An object of the present invention is to make it possible to easily separate a laminate constituting a paper container into a layer made of paper or polyethylene / paper and a layer containing aluminum foil and plastic. Accordingly, it is an object of the present invention to provide a liquid paper container which can be easily disposed of and can effectively reuse resources.

[0004]

A liquid paper container comprising a laminate in which a thermoplastic resin layer, a paper layer, a water-soluble resin layer, an adhesive resin layer, a gas barrier layer, and a thermoplastic resin layer are laminated in this order from the outer surface. Soak the paper container in water or sprinkle water on the paper container after use to dissolve the water-soluble resin layer and peel off the surface layer made of paper and the plastic-based layer from the end of the paper container The used containers can be easily discarded or resources can be easily reused.

In the above-mentioned liquid paper container, the water-soluble resin layer is made of a mixture of a water-soluble resin and polyethyleneimine, or a polyethyleneimine layer is formed between the water-soluble resin layer and the adhesive resin layer to form a water-soluble resin layer. It does not lower the adhesive force between the water-soluble resin layer and the adhesive resin layer, nor does it lower the solubility of the water-soluble resin layer in water.

In the above-mentioned liquid paper container, the gas barrier layer is formed by depositing a laminate of an aluminum foil and a biaxially stretched plastic film or a metal or metal oxide.
By using an axially stretched plastic film, a liquid paper container suitable for packaging sake, wine, coffee, etc., which requires gas barrier properties can be obtained.

The above-mentioned liquid paper container is a gauber top type container comprising a front plate, a rear plate, both side plates, a top forming plate and a bottom forming plate, wherein the bottom forming plate and the outer surface of the top forming plate are connected to each other. Since the adhesive strength adjusting layer is partially formed in the region where the heat bonding is performed, the heat bonding portions of the top and bottom outer surfaces are easily separated from each other, so that it can be easily folded and laminated with water. Separation between layers of the body can be easily performed.

In the above-mentioned liquid paper container, the both side plates and the top forming plate and the bottom forming plate connected to the both side plates are each formed with a vertical folding curve at the center thereof, whereby the both side plates are formed. It is easy to fold inside and fold.

[0009]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a cross-sectional view showing an embodiment of a laminate constituting the liquid paper container of the present invention, and FIG. 2 is a plan view showing a state of a surface of a blank plate of a gobel top type container produced from the laminate shown in FIG. FIG. 3 is a partial perspective view showing a procedure of peeling and disassembling an adhesive portion between outer surfaces of the bottom forming plate of the bottom of the gobel top type container, FIG. 4 is a perspective view showing a folded state of the govel top type container, and FIG. FIG. 6 is a perspective view showing a state in which the surface layer made of polyethylene and paperboard starts to be peeled off from the end of the container in a state where the goebel top type container is folded, and FIG. 6 is a surface layer made of polyethylene and paperboard in a state where the gobel top type container is folded. Is a perspective view showing a state in which is peeled over the entire length of the container, 1 is a polyethylene layer, 2 is a paper layer, 3 is a water-soluble resin layer, 4 is an adhesive resin layer,
5 is a gas barrier layer, 6 is a polyethylene layer, 7 is a printing layer, 8, 9 is an adhesive strength adjusting layer, 11, 12, 13, and 14 are side plates,
11a, 12a, 13a, 14a are top forming plates, 11b, 12b, 13b, 14b
Denotes a bottom forming plate, 15 denotes an adhesive plate, 16 and 17 denote curved lines, 18 denotes a spout mounting hole, and 19 denotes a bottom edge bonding portion.

As shown in FIG. 1, an embodiment of a laminate for producing a liquid paper container according to the present invention comprises a printing layer 7, a polyethylene layer 1, a paper layer 2, a water-soluble resin layer 3, adhesive resin layer 4, aluminum foil 5a and adhesive layer
A gas barrier layer 5 comprising a laminate of 5b and a biaxially stretched polyethylene terephthalate film 5c;
Consists of With the above-described laminated configuration, the water-soluble resin layer 3 is dissolved in water by immersing the paper container in water or by applying water to the paper container, and from the end of the paper container,
Layer composed of polyethylene layer 1 / paper layer 2 and adhesive resin layer 4
/ Gas barrier layer 5 / polyethylene layer 6 can be easily separated. In the above embodiment, the water-soluble resin layer 3 is provided between the paper layer 2 and the adhesive resin layer 4, but the water-soluble resin layer 3 is also provided between the polyethylene layer 1 and the paper layer 2. A stacked configuration can also be used. In that case, it is possible to separate the paper layer 2 into a layer consisting of the polyethylene layer 1, the paper layer 2, and the adhesive resin layer 4 / gas barrier layer 5 / polyethylene layer 6, and to separate only the paper layer 2. Can be. The shape of the liquid paper container manufactured by the above-mentioned laminated body is arbitrary such as a goebel top type, a flat top type (brick type) and the like.

As the water-soluble resin layer 3, a water-soluble resin such as a polyvinyl alcohol resin and polyvinyl pyrrolidone can be used. In particular, polyvinyl alcohol (Gohselan L0301, Nippon Synthetic Chemical Industry) having a low degree of saponification (50% or less) of sulfonic acid modification can be suitably used. The above resins are preferred because of their good solubility in water, methanol and their mixed solvents. In order to form the water-soluble resin layer 3 on the surface of the paper layer 2, the above-mentioned water-soluble resin is dissolved in water or a mixed solvent of water and methanol and applied by gravure printing or coating. Using an ink containing 20 to 25% of a water-soluble resin, a depth of 25
A method of applying by a gravure printing method with a gravure printing plate of μ to 50 μ is preferable. In this case, 1g
The water-soluble resin layer can be uniformly formed to a thickness of up to 6 g / m ² .

As the water-soluble resin layer 3, a predetermined amount of polyethylene imine is mixed with a water-soluble resin such as polyvinyl alcohol resin or polyvinyl pyrrolidone, or the water-soluble resin is applied to the surface of the paper layer 2 and then water-soluble. By further forming a polyethylene imine layer on the surface of the conductive resin, a good laminate can be obtained without lowering the adhesive strength between the water-soluble resin layer 3 and the heat bonding resin layer 4. In order to form a polyethylene imine layer on the water-soluble resin surface, when laminating the water-soluble resin layer 3 and the gas barrier layer 5 of the paper layer 2 by extrusion lamination of the heat bonding resin, an anchor coat is formed on the water-soluble resin layer 3 surface. Can be carried out by using polyethyleneimine.

The polyethylene layer 1 is made of low-density polyethylene, and the polyethylene layer 6 is made of low-density polyethylene, medium-low-density polyethylene, linear low-density polyethylene, and ethylene-α polymerized using a single-site catalyst.
An olefin copolymer or the like is used. 2 for paper layer 2
A paperboard with a basis weight of 50 to 450 g / m ² is used. As the adhesive resin layer 4, low-density polyethylene, ionomer, ethylene-acrylic acid copolymer (EAA), ethylene-methacrylic acid copolymer (EMAA), ethylene-methyl acrylate copolymer (EMA), ethylene-acrylic Ethyl acrylate copolymer (EEA), ethylene-methyl methacrylate copolymer (EMMA) and the like are used. As the gas barrier layer 5, a laminate of an aluminum foil having a thickness of 6 μm to 9 μm and a biaxially stretched polyethylene terephthalate film or a biaxially stretched nylon film, a biaxially stretched polyethylene terephthalate film or a biaxially stretched nylon film on which aluminum is vapor-deposited, A biaxially stretched polyethylene terephthalate film or a biaxially stretched nylon film on which a metal oxide such as silicon is deposited is used.

The shape of the liquid paper container of the present invention may be any shape such as a goebel top type container or a flat top type container. Hereinafter, the goebel top type container will be described. As shown in FIG. 2, a blank plate for producing a goebel top type container is composed of side plates 11, 12, 13, 14 and an adhesive plate 15.
Are connected via creases, and the side plates 11,1
Top forming plates 11a, 12a, 13a, 14a and bottom forming plates 11b, 12b, 13b, 14b are connected to the upper and lower edges of 2, 13, 14 via folds, respectively. In the center, a folding curve 16 is formed in the vertical direction, and the top forming plates 12a, 14a and
In the center of 12b, 14b, a folding curve 17 is formed in the longitudinal direction, and the side plates 11, 12, 13, 14 and the top forming plates 11a, 12a, 13a, 14a or the bottom forming plates 11b, 12b, 13b, 14b are connected. It is formed in a state excluding predetermined dimensions above and below the folded rule. The printed layer 7 is formed except for the area of the surface of the blank plate to which heat bonding is performed, and the area where the surfaces of the bottom forming plates 11b, 12b, 13b, and 14b are thermally bonded and the top forming plates 11a, 12a, and 13a. , 14a are respectively provided with partial adhesive strength adjusting layers 8 and 9 in areas where the surfaces are thermally bonded.

The adhesive strength adjusting layers 8 and 9 are made of an ethylene-vinyl acetate copolymer, a chlorinated ethylene-vinyl acetate copolymer,
To be formed by printing using an ink composed of chlorinated polyethylene, chlorinated polypropylene, cyclized rubber, polyamide resin, urethane resin, acrylic resin, cellulose resin, alkyd resin alone or a mixture thereof. Can be. The area where the adhesive strength adjusting layers 8 and 9 are formed is 20% or more of the area where the surfaces of the bottom forming plates 11b, 12b, 13b and 14b and the top forming plates 11a, 12a, 13a and 14a are thermally bonded. Good to do. The adhesive strength adjusting layers 8 and 9 are formed in a printing step of forming the printing layer 7 on the outer surface of the polyethylene layer 1.

The blank plate shown in FIG. 2 is formed into a tubular shape by thermally bonding the side plate 11 and the bonding plate 15 to form a bottom plate 11b, 12b,
After the bottoms are formed by bending and heat-bonding 13b and 14b, the tops are formed by bending and heat-bonding the top forming plates 11a, 12a, 13a and 14a to obtain a Goebel top type container. When discarding the goebel top type container, the top forming plates 12a and 14a provided with the adhesive strength adjusting layer 9 are provided.
Of the bottom forming plates 12b, 13b, and 14b provided with the adhesive strength adjusting layer 8 are peeled off the portions where the surfaces of the bottom forming plates 12b, 13b, and 14b are thermally bonded to form a gauber top type container. After dismantling the top and bottom parts,
Is bent inward at a folding curve 16 at the center in the width direction, and the top forming plates 12a, 14a and the bottom forming plates 12b, 14b are bent inward at the folding curve 17 at the center in the width direction, respectively. , Can be folded as shown in FIG.

Bottom forming plate provided with adhesive strength adjusting layer 8
The procedure of disassembling the bottom of the Goebel top type container by peeling off the parts of the surfaces of 12b, 13b, and 14b which are thermally bonded is as shown in FIG. 3, from the state shown in FIG. The edge bonding portion 19 is peeled off from the bottom forming plate 13b and raised.
The state shown in (b) is assumed. Further, the portions of the bottom forming plates 12b and 14b where the surfaces are thermally bonded are separated from each other to separate the edge bonding portions 19, and the state shown in FIG. Next, the side plate
12 and 14 are bent inward at the fold curve 16 at the center in the width direction, and the top forming plates 12a and 14a are bent inward at the fold curve 17 at the center in the width direction to form a gauber top type. The container can be in the folded state shown in FIG.

In the folded state of the paper container shown in FIG. 4, the side end of the rear plate 11, the top forming plate 11a and the bottom forming plate 11b bonded to the adhesive plate 15, that is, the end of the laminate is exposed. The water-soluble resin layer 3 of the laminated body is dissolved in water by immersing or spraying the portion with water, and as shown in FIG. 5, the corners of the top forming plate 11a and the bottom forming plate 11b, as shown in FIG. From
The surface layer composed of the polyethylene layer 1 and the paper layer 2 can be peeled off. Peeling can be easily started by immersing the corner end of the paper container in water for 10 to 15 seconds or applying water to the corner end. By applying water to the peeled surface from which the surface layer has been peeled and continuing the peeling, the peeling can be performed over the entire length of the side end portions of the rear plate 11, the top forming plate 11a, and the bottom forming plate 11b as shown in FIG. . By dissolving the water-soluble resin layer 3 of the laminate constituting the paper container with water, a surface layer composed of the polyethylene layer 1 and the paper layer 2,
It can be separated into plastic-based layers consisting of the adhesive resin layer 4, the gas barrier layer 5, and the polyethylene layer 6. Since the separated surface layer and the layer mainly composed of plastic can be treated separately, they can be easily disposed or reused.

[0019]

【Example】

Example 1 400 g of paperboard was laminated with 30 μ polyethylene on one side, and the other side of the paperboard was solid printed with a 45 μ deep gravure printing plate using a water-soluble resin ink having the following composition. A water-soluble resin layer was formed. [Water-soluble resin ink composition (parts by weight)] Water-soluble resin (Gohselan L-301, Nippon Synthetic Chemical Industry) 20 parts Polyethyleneimine (P-1000, Nippon Shokubai) 6 parts Solvent (water 1: methanol 1) 74 parts Separately , A 7μ aluminum foil and a 12μ biaxially stretched polyethylene terephthalate film were laminated using a urethane-based adhesive to produce a laminated film. The water-soluble resin layer surface formed on the other surface of the paperboard and the aluminum foil surface of the laminated film are laminated by extruding an ethylene-methyl methacrylate copolymer with a thickness of 25 μm, and then biaxially stretched polyethylene terephthalate surface. Then, a 40μ polyethylene film is laminated with 20μ extruded polyethylene to obtain 30μ of polyethylene / 400g of paperboard / water-soluble resin layer / ethylene-methyl methacrylate copolymer 25
μ / aluminum foil 7μ / urethane adhesive / biaxially stretched polyethylene terephthalate 12μ / polyethylene 60
A laminate made of μ was produced. The adhesive strength between the water-soluble resin layer surface formed on the paperboard surface of the obtained laminate and the ethylene-methyl methacrylate copolymer layer surface is good, and peeling off the ethylene-methyl methacrylate copolymer layer results in paper peeling. The generated strength was obtained. A printed layer is formed by gravure printing on the 30 μm polyethylene surface of the laminate, and an adhesive strength adjusting layer is formed by printing in a predetermined area, and then a blank for a gobel-top type container is produced by punching. Was attached to a cylinder, and the bottom and top were formed by thermal bonding to produce a Goebel top type container.
The top and bottom of the Goebel top type container obtained above are peeled off at their top and bottom, leaving the paper container in a folded state. The folded paper container is immersed in water for about 10 seconds, and then folded. From the corners of the container, peeling is started from a surface layer made of polyethylene and paperboard and a layer mainly composed of plastic, and the peeling is continued while applying water to the peeling surface, thereby forming a laminated body constituting a paper container. Was easily separated into a surface layer mainly composed of paperboard and a layer mainly composed of plastic.

Example 2 Solid printing was performed using a water-soluble resin ink having the following composition on a gravure printing plate having a depth of 45 μm.
A water-soluble resin layer was formed on the paperboard surface. [Water-soluble resin ink composition (parts by weight)] Water-soluble resin (Gohselan L-301, Nippon Synthetic Chemical Industry) 20 parts Solvent (water 1: methanol 1) 80 parts Then, a methanol solution of 4% polyethyleneimine was added to A laminate for a paper container was prepared in the same manner as in Example 1 except that a polyethyleneimine layer was formed on the water-soluble resin layer surface by printing on the water-soluble resin layer surface using a 25 μm gravure printing plate. Produced. The adhesive strength between the paperboard surface and the ethylene-methyl methacrylate copolymer layer surface of the obtained laminate was good. Using the obtained laminate, it was molded into a Goebel top type container in the same manner as in Example 1. The top and bottom of the obtained paper container are peeled off and adhered to each other on the outer surface, folded and immersed in water to be easily separated into a paperboard-based surface layer and a plastic-based layer. We were able to.

[0021]

According to the present invention, a liquid paper container comprising a laminate of a thermoplastic resin layer, a paper layer, a water-soluble resin layer, an adhesive resin layer, a gas barrier layer, and a thermoplastic resin layer in order from the outer surface is used. The water-soluble resin layer in the laminate is dissolved in water by immersing the used paper container in water or applying water to the paper container, and the surface layer composed of paper and the layer mainly composed of plastic are dissolved from the end of the paper container. The used containers can be easily discarded or resources can be easily reused. In the liquid paper container described above, by forming the water-soluble resin layer as a mixture of a water-soluble resin and polyethyleneimine, a strong adhesive strength can be obtained without reducing the adhesive strength between the water-soluble resin layer and the adhesive resin layer. At the same time, the water-soluble resin layer can be easily dissolved in water without lowering its solubility in water. In the above liquid paper container,
By forming the gas barrier layer as a laminate of an aluminum foil and a biaxially stretched plastic film, or a biaxially stretched plastic film on which a metal or a metal oxide is deposited, alcohol, wine, coffee, and the like that require gas barrier properties can be obtained. It can be a liquid paper container suitable for packaging. The shape of the liquid paper container is a goebel top type container comprising a front plate, a rear plate, both side plates, a top forming plate and a bottom forming plate, wherein the outer surfaces of the bottom forming plate and the top forming plate are hot. By forming the adhesive strength adjusting layer partially in the area to be bonded, the thermal bonding portion between the outer surfaces of the top and the bottom can be easily separated, so that it can be easily folded and easily laminated with water. The body can be peeled and separated into a layer made of paper and a layer made of plastic. In the above-mentioned liquid paper container, the both side plates and the top forming plate and the bottom forming plate that are connected to the both side plates have a configuration in which a vertical folding curve is formed at a central portion, so that the both side plates are folded inward. Makes it easier to fold.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view showing an embodiment of a laminate constituting a liquid paper container of the present invention.

FIG. 2 is a plan view showing a state of a surface of a blank plate of a gobel-top type container manufactured from the laminate shown in FIG. 1;

FIG. 3 is a partial perspective view showing a procedure of peeling and disassembling an adhesive portion between outer surfaces of a bottom forming plate of a goebel top type container.

FIG. 4 is a perspective view showing a folded state of the goebel top type container.

FIG. 5 is a perspective view showing a state in which the surface layer made of polyethylene and paperboard starts to be peeled off from the end of the container in a state where the goebel top type container is folded.

FIG. 6 is a perspective view showing a state in which a surface layer made of polyethylene and paperboard is peeled off over the entire length of the container in a state where the goebel top type container is folded.

[Explanation of symbols]

1 Polyethylene layer 11, 12, 13, 14 Side plate 2 Paper layer 11a, 12a, 13a, 14a
Top forming plate 3 Water-soluble resin layer 11b, 12b, 13b, 14b
Bottom forming plate 4 Adhesive resin layer 15 Adhesive plate 5 Gas barrier layer 16, 17-fold curve 6 Polyethylene layer 18 Outlet mounting hole 7 Printing layer 19 Bottom edge adhesive part 8, 9 Adhesive strength adjustment layer

 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Keiji Takezawa 10 Uzumasa Senbaicho, Ukyo-ku, Kyoto Dai Nippon Printing Co., Ltd.

Claims (6)

[Claims] 1. A liquid comprising a laminate having a structure in which a thermoplastic resin layer, a paper layer, a water-soluble resin layer, an adhesive resin layer, a gas barrier layer, and a thermoplastic resin layer are laminated in this order from the outer surface. Paper container. 2. The liquid paper container according to claim 1, wherein the water-soluble resin layer is made of a mixture of a water-soluble resin and polyethylene imine. 3. The liquid paper container according to claim 1, wherein a polyethylene imine layer is formed between the water-soluble resin layer and the adhesive resin layer. 4. The gas barrier layer according to claim 1, wherein the gas barrier layer is a laminate of an aluminum foil and a biaxially stretched plastic film, or a biaxially stretched plastic film on which metal or metal oxide is deposited. Liquid paper container. 5. The liquid paper container according to claim 1, wherein the liquid paper container is a gobel top type container comprising a front plate, a rear plate, both side plates, a top forming plate and a bottom forming plate, wherein the bottom forming plate and the top portion. A liquid paper container, wherein an adhesive strength adjusting layer is partially formed in a region where the outer surfaces of the forming plate are thermally bonded. 6. The liquid paper container according to claim 5, wherein
A liquid paper container having a configuration in which a vertical fold curve is formed at the center of the top forming plate and the bottom forming plate that are connected vertically above and below the both side plates, respectively.