JP2004330420A - Laminate for paper container and its manufacturing method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a laminate for a paper container capable of being heat-sealed even at a low temperature with high sealing strength at the time of forming a paper container and capable of preventing the occurrence of foreign matter. <P>SOLUTION: The laminate for the paper container has at least a paper layer 8, a barrier layer 5 provided inside the paper layer and the heat-sealing layer 10 provided inside the barrier layer. The heat-sealing layer 10 is formed by laminating an ozone-treated layer 3 of linear low density polyethylene, which is manufactured using a metallocene catalyst, on the barrier layer through an adhesive layer. Further, a layer 2 comprising linear low density polyethylene, which is manufactured using a metallocene catalyst, is laminated on the ozone-treated linear low density polyethylene layer as the layer constituting the innermost layer of the paper container. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a laminate for paper containers mainly used for filling and packaging of foods such as beverages and yogurt, and a method for producing the same.
[0002]
[Prior art]
BACKGROUND ART Conventionally, paper containers (paper packs, paper cups) used for filling and packaging of foods such as beverages and yogurt are known. Such a paper container is required to have shape retention, water resistance, oxygen barrier properties, and the like. Therefore, for example, a laminate in which a synthetic resin made of polyethylene, polyester, or the like, an aluminum foil, or the like is laminated (laminated) on base paper. It is molded from.
[0003]
Various types of laminates for paper containers have been proposed. For example, a co-pressed film having a polyethylene layer on both sides and a barrier layer in the middle is sand-processed on base paper, and a heat seal layer (innermost layer) is further formed. Some are laminated.
Also, a laminate in which low-density polyethylene (LDPE) is laminated on the inner surface of the barrier film via an adhesive (anchor coat (AC) agent), and a base paper, a polyethylene layer, and the like are laminated on the outer surface of the barrier layer. Is used. In such a laminate, the container is formed by heat-sealing the low-density polyethylene which is the innermost layer of the container.
[0004]
However, when the innermost layer to be the heat seal layer is LDPE, sufficient heat sealing may not be obtained if the heat seal is performed at a low temperature. On the other hand, if the molding temperature is increased to increase the sealing strength and the paper cup is molded, scum (foreign matter) made of polyethylene resin (PE) used as the outermost layer of the cup is generated, and the inner surface of the stacked cups is formed. Foreign matter sometimes adhered. For example, when PE having a higher density (higher melting point) than the inner layer is laminated on the outer surface of the container for the purpose of imparting heat resistance, the temperature at the time of molding is high. In some cases, PE foreign matter was generated due to rubbing with a mold or the like and adhered to the cup.
[0005]
On the other hand, a laminate has been proposed in which a barrier layer, an adhesive layer, a polyethylene layer, and a linear low-density polyethylene layer (LLDPE layer) produced using a metallocene catalyst are sequentially laminated inside a paper layer ( Patent Document 1).
This laminate is heat-sealed and molded so that the linear low-density polyethylene layer produced using the metallocene catalyst is the innermost layer of the container, whereby the shape of the container is favorably maintained by the polyethylene layer. In addition, it is described that the container can be easily opened by forming the innermost layer as an LLDPE layer manufactured using a metallocene catalyst.
[0006]
However, in such a laminate, it is generally necessary to process the resin at a resin temperature of 310 ° C. or more during lamination of polyethylene in order to obtain sufficient lamination strength. On the other hand, linear low-density polyethylene (hereinafter sometimes abbreviated as “metallocene-based LLDPE”) produced using a metallocene catalyst serving as the innermost layer is thermally decomposed when exposed to high temperatures. Low temperature processing at a resin temperature of 310 to 250 ° C, preferably 295 to 270 ° C is required. For this reason, there is a problem that sufficient compatibility cannot be obtained at the interface between the polyethylene layer and the metallocene-based LLDPE layer due to the difference in the degree of surface oxidation. Therefore, when a paper container is formed using such a laminate, there is a problem that the original performance cannot be sufficiently exhibited with respect to the low-temperature sealing property and the heat sealing strength (sealing strength) which are the characteristics of the metallocene-based LLDPE.
[0007]
[Patent Document 1]
JP-A-2002-205363
[Problems to be solved by the invention]
In view of the problems described above, the present invention provides a paper container laminate that can be heat-sealed with high sealing strength even at a low temperature when forming a paper container and that can prevent generation of foreign matter. Main purpose.
[0009]
[Means for Solving the Problems]
In order to achieve the above object, according to the present invention, there is provided a laminate for a paper container, comprising at least a paper layer, a barrier layer inside the barrier layer, and a heat seal layer inside the barrier layer. Then, as a heat seal layer constituting the innermost layer of the paper container, a linear low-density polyethylene layer produced using a metallocene catalyst and subjected to ozone treatment is provided on the barrier layer via an adhesive layer. A laminate for a paper container characterized by being laminated is provided.
[0010]
If the linear low-density polyethylene layer produced using the metallocene catalyst and subjected to the ozone treatment is laminated on the barrier layer via the adhesive layer, the laminating process is performed at a high temperature of 310 ° C. or more. Even without this, the adhesive strength between the barrier layer and the linear low-density polyethylene layer is kept sufficiently high. When a container is formed using this laminate, for example, heat sealing can be performed at a temperature lower by about 80 ° C. than in the past (low-temperature heat sealing), and high sealing strength can be achieved. At the same time, the generation of foreign matter can be effectively prevented. Further, by increasing the sealing strength, high airtightness can be maintained.
[0011]
In the present invention, the laminate for a paper container has at least a paper layer, a barrier layer inside the paper layer, and a heat seal layer inside the barrier layer, wherein the heat seal layer is A linear low-density polyethylene layer produced using a metallocene catalyst and subjected to ozone treatment, which is laminated on the barrier layer via an adhesive layer, and further the innermost layer of the paper container. As a constituent, a linear low-density polyethylene layer produced using a metallocene catalyst is characterized by being laminated on the ozone-treated linear low-density polyethylene layer. A laminate for a paper container is provided.
[0012]
Thus, as a heat seal layer, if the laminated body for a paper container having a two-layer structure of a linear low-density polyethylene layer produced using a metallocene catalyst, high-temperature laminating at 310 ° C. or higher is unnecessary, Since they are the same metallocene-based LLDPE, low-temperature processing results in good compatibility and high lamination strength. Further, even at the time of paper container molding, processing can be performed at a temperature as low as 80 ° C., which is excellent in low-temperature sealability, sealing strength, and airtightness. In addition, the grade can be changed between the inner metallocene-based LLDPE layer and the outer metallocene-based LLDPE layer, and the innermost layer can be more excellent in sealing properties and filling suitability (slipperiness, etc.). . It is also possible to make the heat seal layer excellent in thickness uniformity and the like over the entire heat seal layer.
[0013]
In the present invention, a low-density polyethylene layer, a paper layer, and a polyethylene layer may be sequentially laminated on the outer surface of the barrier layer.
If the paper layer is sanded with, for example, a low-density polyethylene layer, and is laminated on the outer surface of the barrier layer, high heat resistance and water resistance can be obtained.
[0014]
The barrier layer is preferably made of an ethylene-vinyl alcohol copolymer or a transparent vapor-deposited film.
If the barrier layer is made of an ethylene-vinyl alcohol copolymer or a transparent vapor-deposited film, the adhesive strength to the metallocene-based LLDPE layer is high, and a high barrier property against gas such as oxygen is exhibited. It is suitable as a laminated body for a paper container.
[0015]
Furthermore, according to the present invention, there is provided a method for producing a laminate for a paper container, wherein at least a step of coating an adhesive on a surface on the inner side of the barrier film, and a method for producing a linear structure produced using a metallocene catalyst. A step of subjecting one surface of the low-density polyethylene layer to ozone treatment and laminating the barrier film and the adhesive via the adhesive to form a laminate having a barrier layer, and applying a low-density polyethylene resin to a surface outside the barrier layer. The present invention provides a method for producing a laminate for a paper container, comprising: a step of extruding and further sequentially laminating a base paper on the outside thereof; and a step of further extruding and laminating a polyethylene resin on the outside of the base paper.
If the laminate for paper containers is manufactured by such a process, the laminate for paper containers according to the present invention, which is excellent in lamination strength and low-temperature sealability, can be manufactured at low cost.
[0016]
In this case, after the step of forming the laminate having the barrier layer, a linear low-density polyethylene layer produced using a metallocene catalyst may be further laminated on the inner surface of the laminate.
[0017]
As described above, when the linear low-density polyethylene resin produced using the metallocene catalyst is further extruded and laminated as the innermost layer, the heat seal layer has a two-layer structure, and the thickness uniformity can be improved. At the same time, defects such as pinholes can be eliminated. Further, since the extrusion speed can be made higher than in the case where the heat seal layer having the same thickness is formed by one thick film, the productivity can be improved.
[0018]
Further, after the step of forming the laminate having the barrier layer, an adhesive may be coated on a surface outside the barrier layer, and then the low-density polyethylene resin may be laminated.
If the low-density polyethylene resin is laminated after coating the barrier layer with the adhesive as described above, the lamination can be performed with higher adhesive strength.
[0019]
As the barrier film, an ethylene-vinyl alcohol copolymer film or a transparent vapor-deposited film can be suitably used.
If an ethylene-vinyl alcohol copolymer film or a transparent vapor-deposited film is used, a laminate for a paper container having high adhesiveness with a heat seal layer made of an ozone-treated metallocene-based LLDPE and having excellent gas barrier properties such as oxygen can be obtained. Can be manufactured.
[0020]
The steps before coating the adhesive on the outer surface of the laminate having the barrier layer are performed in one continuous line, and the adhesive is coated on the outer surface of the laminate having the barrier layer. It is preferable that the steps are performed in an independent step, and the steps after coating the adhesive on the outer surface of the laminate having the barrier layer are performed in one continuous line.
If the production is performed by dividing into such lines, stagnation of the entire production line can be prevented, the production can be performed efficiently, and the laminate of the present invention can be produced using the existing line, and the cost can be reduced. Can be greatly reduced.
[0021]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, a laminate for a paper container according to the present invention and a method for producing the laminate will be specifically described with reference to the drawings.
FIG. 1 shows a schematic configuration of an example of the paper container laminate according to the present invention. In the laminate 1, a low-density polyethylene layer 7, a paper layer 8, and a low-density polyethylene layer 9 are sequentially laminated on an outer surface of a barrier layer 5 made of an ethylene-vinyl alcohol copolymer (EVOH) via an adhesive layer 6. Have been. On the other hand, a linear low-density polyethylene layer 3 manufactured using a metallocene catalyst and subjected to ozone treatment is provided on the inside of the barrier layer 5 as the heat seal layer 10. A linear low-density polyethylene layer 2 produced using a metallocene catalyst is further laminated as an innermost layer of the paper container.
[0022]
On the other hand, FIG. 2 shows a schematic configuration of another example of the paper container laminate according to the present invention. In the paper container laminate 21, the ozone-treated linear low-density polyethylene layer 3 manufactured using a metallocene catalyst and serving as a heat seal layer constituting the innermost layer of the paper container is a barrier layer. 5 is laminated via an adhesive layer 4.
[0023]
As described above, the laminated bodies 1 and 21 in which the linear low-density polyethylene layer 3 produced using the metallocene catalyst and subjected to the ozone treatment are laminated on the barrier layer 5 with the adhesive layer 4 interposed therebetween. By doing so, the lamination strength between the barrier layer 5 and the metallocene-based LLDPE layer 3 can be kept sufficiently high even if the lamination is performed at a low temperature. Further, in the paper container forming process, a paper container having high sealing strength and high airtightness can be formed even though the metallocene-based LLDPE layers 2 and 3 are heat-sealed at a low temperature. Therefore, generation of foreign matter during molding can be effectively prevented.
[0024]
Next, a specific method for producing the laminate for a paper container according to the present invention will be described. Drawing 3 is an explanatory view showing an example of a manufacturing process of a layered product for paper containers concerning the present invention.
First, in a continuous line (A) using a so-called tandem laminator provided with two extruders 13a and 13b, a laminate 1a having a barrier layer 5 shown in FIG. 4 is manufactured.
[0025]
In the first step (A-1), the adhesive 4 is coated on the EVOH film 5 unwound from the roll. Specifically, the adhesive (anchor coating agent) 4 is thinly coated on the inner surface of the container of the barrier film 5 using the anchor coating device 11 and then passed through the drying chamber 12 so that the adhesive (the adhesive layer) is formed. 4) Dry 4 to some extent.
In addition, what is called a transparent vapor deposition film can also be used as a barrier film. For example, a transparent vapor-deposited film obtained by vapor-depositing a mineral (inorganic substance) such as silica or alumina on a base material such as nylon, OPP (biaxially-stretched polypropylene), or PET is preferable because it has a high barrier property. . Also, a film made of nylon or PET can be used without being vapor-deposited.
[0026]
Next, in the step (A-2), the metallocene-based LLDPE film 3 and the barrier film 5 are laminated via the adhesive 4 coated on the barrier film 5.
The metallocene-based LLDPE film 3 can be continuously formed by melting a metallocene-based LLDPE resin in an extruder 13a and extruding the molten resin from a T-die. The film thickness depends on the contents to be filled in the paper container and the performance of the extruder 13a, but can be, for example, 15 to 30 μm. At this time, the temperature of the metallocene-based LLDPE resin is kept at a low temperature of 295 ° C. or less so as not to decompose. In the present invention, unlike a film which is formed in advance, such as the barrier film 5, a film formed by extruding a molten resin from a T-die is referred to as a film.
[0027]
The metallocene-based LLDPE film 3 extruded from the T-die and the barrier film 5 can be laminated via the adhesive 4 by being passed between a pair of rolls 15a and pressure-bonded. At this time, before lamination, One side of the metallocene-based LLDPE film 3 (the surface to be bonded to the barrier film / adhesive) is subjected to ozone treatment. By spraying ozone onto the metallocene-based LLDPE film 3 from the nozzle 14, oxidation of the bonding surface with the barrier film 5 is promoted, and sufficient bonding strength can be ensured even at a resin temperature of 295 ° C. or less. Therefore, after the ozone treatment, pressure bonding is performed at a resin temperature of 295 ° C. or less, whereby the barrier film 5 and the ozone-treated metallocene-based LLDPE film 3 are firmly adhered to each other via the adhesive 4. (Barrier layer 5 / AC layer 4 / ozone-treated metallocene-based LLDPE layer 3) can be obtained.
[0028]
In the step (A-3), a layer having a barrier layer (barrier layer 5 / AC layer 4 / ozone-treated metallocene-based LLDPE layer 3) was further manufactured using a metallocene catalyst on the inner surface. The linear low density polyethylene layer 2 is laminated. Specifically, the metallocene-based LLDPE film 2 extruded from the T-die of the extruder 13b similar to the case of the step (A-2) is rolled to the metallocene-based LLDPE layer 3 side of the laminate having the barrier layer 5. 15b. Also at this time, the temperature of the metallocene-based LLDPE resin is kept at a low temperature of 295 ° C. or less so as not to decompose. Here, the metallocene-based LLDPE layers 2 and 3 are pressure-bonded to each other, and since they have similar properties, they can be bonded with high strength even at a low temperature of 295 ° C. or lower without using an adhesive. Note that the metallocene-based LLDPE layer 2 to be laminated here constitutes the heat seal layer 10 and also becomes the innermost layer. Therefore, by adjusting the type and amount of the additive as needed, the sealing property and the filling suitability (sliding property) can be improved. For example, a grade with higher safety may be selected, or a grade with higher safety may be selected in consideration of contact with food.
[0029]
As described above, the metallocene-based LLDPE layers 2 and 3 doublely laminated in the steps (A-2) and (A-3) function as the heat seal layer 10 when molded into a paper container. . If the metallocene-based LLDPE layers 3 and 2 are laminated in two steps as described above, for example, even if the thickness of one layer is 15 to 30 μm, the thickness can be reduced to 30 to 60 μm by using two layers. A sufficient thickness can be secured for the entire sealing layer 10. Further, for example, even if there is a pinhole or an extremely thin portion in the first layer, it can be supplemented by the second layer, so that the uniformity and reliability of the thickness of the entire heat seal layer 10 are improved. be able to.
[0030]
When the heat seal layer 10 is formed of one thick metallocene-based LLDPE film, it is necessary to extrude a relatively thick film from the T-die of the extruder. In this case, the load applied to the extruder increases. The extrusion speed will be reduced. On the other hand, if a relatively thin metallocene-based LLDPE film is extruded and laminated in two steps, the load can be reduced and the extrusion can be performed at a high speed, so that the productivity can be improved.
[0031]
When the required thickness of the laminate is relatively small (for example, the thickness of the heat seal layer is about 30 μm or less) or when the extruder to be used has high performance, the step (A-2) is performed. After subjecting one side of the metallocene-based LLDPE film to ozone treatment and laminating it via a barrier film and an adhesive to form a laminate having a barrier layer 5, the lamination of the metallocene-based LLDPE layer in step (A-3) is omitted. May be. In this case, the paper container laminate 21 having the structure shown in FIG. 2 is obtained through the subsequent steps.
[0032]
By laminating the metallocene-based LLDPE layer 2 in the step (A-3) as described above, the laminate 1a having the barrier layer shown in FIG. 4 (barrier layer 5 / AC layer 4 / ozone-treated metallocene-based LLDPE layer 3 / A metallocene-based LLDPE layer 2) is obtained, which is wound up into a roll.
[0033]
Next, in an independent step, that is, an off-line step (B), the outside of the laminate 1a having the barrier layer 5 (the barrier layer 5 / the AC layer 4 / the ozone-treated metallocene-based LLDPE layer 3 / the metallocene-based LLDPE layer 2). The surface to be formed, that is, the barrier layer 5 side is coated with an adhesive 6 (AC coating).
Since a low-density polyethylene layer to be laminated in the next step can be directly laminated on the outside of the barrier layer 5, the AC coating in the off-line step (B) can be omitted in this case.
[0034]
After coating the adhesive 6 on the outer surface of the laminate 1a having the barrier layer 5 as described above, the subsequent steps are performed again on one continuous line (C).
First, in the step (C-1), the low-density polyethylene layer 7 and the base paper 8 are sequentially laminated via an adhesive coated on the outside of the barrier layer 5. Specifically, the base paper 8 and the laminate 1a having the barrier layer 5 are supplied between the rolls 15c, and the low-density polyethylene film 7 is supplied between the rolls 15c from the T-die of the extruder 13c. At this time, the laminate 1 a having the barrier layer is supplied such that the surface coated with the adhesive 6 is bonded to the low-density polyethylene film 7.
Thereby, a laminate in which the low-density polyethylene layer 7 is sandwiched by the laminate 1a having the base paper 8 and the barrier layer 5 is formed between the rolls 15c.
[0035]
Next, in the step (C-2), a low-density polyethylene layer 9 is further laminated as an outermost layer outside the base paper 8. Specifically, the low-density polyethylene film 9 obtained by the T-die of the extruder 13d is supplied between the rolls 15d, and the laminate obtained in the step (C-1) is mixed with the low-density polyethylene film. It is supplied in the direction to be bonded to the film 9. As the outermost layer, polyethylene other than low-density polyethylene (about 0.910 to 0.925 g / cm ³ ), for example, medium-density polyethylene (about 0.926 to 0.940 g / cm ³ ), high-density polyethylene (about 0.926 to 0.940 g / cm ³ ) 0.941 g / cm ³ or more) can also be suitably used.
Then, after passing through the roll 15d, the obtained paper container laminate 1 (low-density polyethylene layer 9 / paper layer 8 / low-density polyethylene layer 7 / AC layer 6 / barrier layer 5 / AC layer 4 / ozone-treated). The production is completed by winding the metallocene-based LLDPE layer 3 / metallocene-based LLDPE layer 2).
[0036]
The laminated body 1 for a paper container manufactured as described above has no defects such as pinholes over the entire heat seal layer 10, has excellent adhesiveness with the barrier layer / adhesive layer side, and has good sealing properties on the innermost layer side. Excellent filling suitability (slipperiness, etc.) and high lamination strength and low-temperature sealability can be obtained.
Therefore, even when heat sealing is performed at a low temperature during the molding of the container, the sealing performance is excellent, and the generation of foreign matter can be effectively prevented. When the container is molded, the innermost layer is composed of metallocene-based LLDPE. However, since metallocene-based LLDPE has no problem with regard to odor and the like, it can be suitably used as a packaging container for foods such as drinks and yogurt. it can.
[0037]
【Example】
Hereinafter, examples and comparative examples of the present invention will be described.
<Example>
According to the process shown in FIG. 3, as shown in FIG. 1, the low-density polyethylene layer 9 / paper layer 8 / low-density polyethylene layer 7 / AC layer 6 / barrier layer 5 / AC layer 4 / The laminated body 1 in which the ozone-treated metallocene-based LLDPE layer 3 / metallocene-based LLDPE layer 2 were laminated in this order was manufactured.
[0038]
<Comparative example>
A conventional laminate for a paper container in which the heat seal layer is made of low-density polyethylene, that is, a low-density polyethylene layer / paper layer / low-density polyethylene layer / AC layer / barrier layer / AC layer / low-density from the outer surface side of the container. A laminate in which polyethylene layers were laminated in this order was manufactured.
[0039]
<Evaluation>
Using the above two laminates, a paper cup was formed by heat sealing, and a leak test, dimensional accuracy measurement and the like were evaluated. As a result, in the laminate of the example, even if heat sealing was performed with hot air at a temperature lower by 80 ° C. than that of the comparative example, sufficient sealing properties, sealing strength, and high airtightness could be achieved, and generation of foreign matters was possible. Was surely prevented.
[0040]
Note that the present invention is not limited to the above embodiment. The above embodiment is merely an example, and any embodiment having substantially the same configuration as the technical idea described in the claims of the present invention and having the same function and effect will be described. It is included in the technical scope of the invention.
[0041]
For example, the manufacturing process of the laminate for a paper container according to the present invention is not limited to the process shown in FIG. 3, and various changes may be made. That is, each step may be performed independently, or all the steps may be configured by one line. As for the material of each layer such as a barrier layer and a paper layer other than the heat seal layer, any conventionally used materials can be used. The use of the paper container to be molded is not particularly limited.
[0042]
【The invention's effect】
As described above, in the laminate for a paper container of the present invention, as a heat seal layer constituting the innermost layer of the paper container, a linear low-density polyethylene layer produced using a metallocene catalyst and subjected to ozone treatment. Is laminated on the barrier layer via an adhesive layer, and in particular, by further laminating a linear low-density polyethylene layer produced using a metallocene catalyst as the innermost layer, the adhesion between the heat seal layer and the barrier layer is improved. The metallocene-based LLDPE of the heat-sealing layer can be sufficiently melted and heat-sealed at a relatively low temperature when formed into a paper container. As a result, airtightness is improved, and high barrier properties can be maintained. Further, generation of foreign matter can be effectively prevented.
[Brief description of the drawings]
FIG. 1 is a schematic configuration diagram illustrating an example of a paper container laminate according to the present invention.
FIG. 2 is a schematic configuration diagram showing another example of the paper container laminate according to the present invention.
FIG. 3 is an explanatory view showing an example of a production process of the paper container laminate according to the present invention.
FIG. 4 is a schematic configuration diagram showing a laminate having a barrier layer.
[Explanation of symbols]
1, 21: laminate for paper container, 1a: laminate having barrier layer,
2. Metallocene-based LLDPE layer (film),
3 ... ozone-treated metallocene-based LLDPE layer (film),
4 ... adhesive layer (adhesive, AC layer) 5 ... barrier layer (EVOH film)
6 ... adhesive layer (AC layer) 7 ... low density polyethylene layer (membrane)
8: paper layer (base paper), 9: low density polyethylene layer (membrane),
10: heat seal layer, 11: anchor coating device, 12: drying room,
13 ... an extruder, 14 ... a nozzle, 15 ... a roll.

Claims (9)

A laminate for a paper container, comprising at least a paper layer, a barrier layer inside the paper layer, and a heat seal layer inside the barrier layer, and a heat seal forming an innermost layer of the paper container Paper, characterized in that a linear low-density polyethylene layer produced using a metallocene catalyst and subjected to an ozone treatment is laminated on the barrier layer via an adhesive layer as a layer. A laminate for containers. A laminate for a paper container, comprising at least a paper layer, a barrier layer on the inside thereof, and a heat seal layer on the inside of the barrier layer, wherein the heat seal layer uses a metallocene catalyst. Manufactured, and the ozone-treated linear low-density polyethylene layer is laminated on the barrier layer via an adhesive layer, and further constitutes the innermost layer of the paper container, A laminate for a paper container, wherein a linear low-density polyethylene layer produced using a metallocene catalyst is laminated on the ozone-treated linear low-density polyethylene layer. . The laminated body for a paper container according to claim 1 or 2, wherein a low-density polyethylene layer, a paper layer, and a polyethylene layer are sequentially laminated on an outer surface of the barrier layer. The paper container laminate according to any one of claims 1 to 3, wherein the barrier layer is made of an ethylene-vinyl alcohol copolymer or a transparent vapor-deposited film. A method of manufacturing a laminate for a paper container, at least a step of coating an adhesive on the inner surface of the barrier film, and one side of a linear low-density polyethylene layer manufactured using a metallocene catalyst. Applying an ozone treatment and laminating the barrier film and the adhesive via the adhesive to form a laminate having a barrier layer, and extruding a low-density polyethylene resin on a surface outside the barrier layer; And a step of extruding and laminating a polyethylene resin on the outside of the base paper to laminate the paper container. After the step of forming a laminate having the barrier layer, a linear low-density polyethylene layer produced using a metallocene catalyst is further laminated on a surface inside the laminate. 6. The method for producing a laminate for paper containers according to 5. After the step of forming a laminate having the barrier layer, an adhesive is coated on a surface outside the barrier layer, and then the low-density polyethylene resin is laminated. A method for producing the laminate for a paper container according to the above. The method for producing a laminate for a paper container according to any one of claims 5 to 7, wherein an ethylene-vinyl alcohol copolymer film or a transparent vapor-deposited film is used as the barrier film. The steps before coating the adhesive on the outer surface of the laminate having the barrier layer are performed in one continuous line, and the adhesive is coated on the outer surface of the laminate having the barrier layer. 9. The method according to claim 7, wherein each of the steps is performed in an independent step, and each step after coating an adhesive on an outer surface of the laminate having the barrier layer is performed in one continuous line. 3. The method for producing a laminate for paper containers according to item 1.

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