JP2019156459A - Paper container for liquid - Google Patents

Abstract

To provide a paper container for liquid which can prevent bubbling or pin-holes from occurring due to heating by hot air during making of the paper container for liquid, and is free from liquid leakage.SOLUTION: A paper container for liquid comprising a laminate with paper as base material, and thermoplastic resin layers as the innermost layer and the outermost layer is characterized as such that the outermost thermoplastic resin layer is provided in a stripe shape using an extruder, and of the thermoplastic resin provided in a stripe shape, the width of the part where thermoplastic resin is applied is in a range of more than 5 μm and equal to or less than 500 μm, and the gap between the stripes is in a range of more than 5 μm and equal to or less than 500 μm.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a liquid paper container. Especially for liquid or paper containers that are made by heat sealing with a thermoplastic resin layer on the front and back using paper as a base material, a liquid paper container that can be boxed without being affected by moisture contained in the paper base material. is there.

  The liquid paper container is generally composed of a laminate having paper as a base material. Liquid paper containers have become established as indispensable for modern daily life, such as milk, various beverage containers, liquid seasoning containers such as soy sauce and soup stock, and liquid containers for alcoholic beverages. .

  These liquid paper containers have a structure consisting of a paper base material and a sealant layer, an aluminum foil, a metal vapor deposition film, a metal oxide vapor deposition film between the paper layer and the sealant layer, or a gas barrier layer, or Some have a layer having gas barrier properties such as an inorganic compound vapor-deposited film.

  A sealant layer is provided on the inner layer of the container. A three-dimensional shape can be formed in a box shape by the sealant layer to form a liquid paper container, and the container can be sealed after filling the contents. Generally, a polyolefin resin is used for the sealant layer.

  In addition, some liquid paper containers, for example, paper containers having a roof-shaped top called a “Gebel top type”, have a stopper made of polyethylene resin attached to the slope of the roof by thermal bonding.

  In general, blanks with a configuration in which polyolefin resin is arranged at least on the front and back of paper as a base material are used. In that case, moisture contained in the paper base material becomes an unstable factor, and heat sealing and box making are required. This may become an obstacle to quality stability.

  In other words, the moisture contained in the paper base material becomes water vapor during hot air heating for heat sealing, but because the front and back are covered with resin, they lose their escape and generate bubbling or pinholes. If the box is made or filled with liquid, it may cause liquid leakage.

  On the other hand, Patent Document 1 proposes to partially increase the thickness of the thermoplastic resin of the innermost layer, but it cannot be said that sufficient verification regarding the above-mentioned problem has been made. .

Japanese Patent Laid-Open No. 7-132932

  The present invention has been made in view of such a situation, and prevents liquid bubbling or pinholes from being generated by hot air heating without causing a reduction in sealing strength in the liquid paper container box making, and liquid paper free from liquid leakage. It is an object to make it possible to provide a container.

As means for solving the above problems, the invention according to claim 1
It is a liquid paper container consisting of a laminate having a thermoplastic resin layer as an innermost layer and an outermost layer, using paper as a base material,
The outermost thermoplastic resin layer is provided in stripes using an extruder,
The thermoplastic resin provided in a stripe shape has a width of the portion to which the thermoplastic resin is applied in a range of more than 5 μm and 500 μm or less,
The liquid paper container is characterized in that the gap between the stripes is in the range of more than 5 μm and not more than 500 μm.

The invention according to claim 2
2. The liquid paper container according to claim 1, wherein the thermoplastic resin layer is made of a polyethylene resin.

The invention according to claim 3
The liquid paper container according to claim 1, wherein a gas barrier layer is provided between the paper base material and the innermost thermoplastic resin layer.

  According to the present invention, it is possible to provide a liquid paper container free from liquid leakage by preventing the occurrence of bubbling or pinholes due to hot air heating without reducing the sealing strength in the boxing of the liquid paper container. Can do.

  In particular, according to the second aspect of the present invention, it is possible to prevent the occurrence of bubbling or pinholes due to hot air heating without reducing the sealing strength in the boxing of the liquid paper container. In providing, it is possible to provide using a material that is relatively inexpensive and easy to form.

  In particular, according to the third aspect of the present invention, the liquid paper container can be prevented from causing bubbling or pinholes due to hot air heating without causing a decrease in the sealing strength in the liquid paper container making, and the liquid paper container free from liquid leakage. When providing, it is possible to obtain a liquid paper container having better gas barrier performance.

FIG. 1 is a schematic perspective view for explaining one embodiment of a laminated body constituting a liquid paper container according to the present invention. FIG. 2 is a partial cross-sectional schematic diagram for explaining how a laminated body constituting a general liquid paper container generates a pinhole due to moisture contained in the paper base material when hot air is blown. FIG. 3 is a partial cross-sectional schematic diagram for explaining how moisture contained in a paper base material is released when a laminate constituting a liquid paper container according to the present invention is sprayed with hot air. FIG. 4 is a schematic perspective view for explaining the stripe width of the outermost thermoplastic resin layer and the gap between the stripes of the laminate constituting the body paper container according to the present invention. FIG. 5 is a partial cross-sectional schematic diagram for explaining an embodiment having a gas barrier layer of a laminate constituting the liquid paper container according to the present invention, and a partial cross-sectional schematic diagram for explaining examples and comparative examples. FIG.

Hereinafter, the present invention will be described in more detail with reference to the drawings. However, the present invention is not limited to the examples shown here. The invention is limited only by the following claims.

  FIG. 1 is a schematic perspective view for explaining one embodiment of a laminated body constituting a liquid paper container according to the present invention.

  The liquid paper container according to the present invention comprises a laminate (10) having paper as a base material (1), the innermost layer having a thermoplastic blue resin layer (3), and the outermost layer having a thermoplastic resin layer (2). . Further, the outermost thermoplastic resin layer (2) is provided in the shape of a stripe (4) using an extruder.

  The shape of the stripe (4) is, for example, that a comb blade-shaped stopper is provided in a slit portion for discharging the molten resin of the extruder so that the base material (1) can be applied without applying the molten resin. It can be realized by alternately forming the exposed portions along the flow direction of the substrate.

  Moreover, a thermoplastic resin layer (2) and a thermoplastic resin layer (3) can be made into a polyethylene resin. As a result, in making a liquid paper container, a material that is relatively inexpensive and easy to form a film in preventing the occurrence of bubbling or pinholes due to hot air heating from the inside of the container and providing a liquid paper container that does not leak. It becomes possible to provide using.

  Furthermore, as a result of intensive studies as we proceeded with the present invention, the outermost thermoplastic resin layer (2) provided in the stripe (4) shape has a width of the portion to which the thermoplastic resin is applied. Has been found to be in the range of more than 5 μm and not more than 500 μm, and the gap between stripes needs to be in the range of more than 5 μm and not more than 500 μm.

  That is, since the thermoplastic resin layer (2) is within this range, the liquid paper container according to the present invention does not interfere with the heat sealability when it is manufactured using heat seal, and will be described later. Generation of pinholes due to hot air blowing can be prevented.

  FIG. 2 is a partial cross-sectional schematic diagram for explaining how a laminated body constituting a general liquid paper container generates a pinhole due to moisture contained in the paper base material when hot air is blown.

  The example shown in FIG. 2 is an example of a laminated body (10) constituting a general liquid paper container. The substrate (1) is a paper substrate, and generally the paper substrate contains a certain amount of moisture (5). As shown in FIG. 2A, the front and back of the paper base are covered with a thermoplastic resin layer (2) and a thermoplastic resin layer (3).

  When performing box making by heat sealing, as shown in (B), after the hot air (6) is heated by spraying from the inside of the container, the heat sealing is performed with the thermoplastic address layers facing each other.

  At this time, as shown in (C), the moisture (5) in the heated paper substrate is vaporized and tends to come out from the paper substrate, but the front and back are the thermoplastic resin layer (2), and Since it is covered with the thermoplastic resin layer (3), it loses its destination.

The vaporized water (5) subsequently penetrates the thermoplastic resin layer (3) inside the container already softened by the hot air (6) as shown in (D), and there is a pinhole (7). Is formed. The pinhole (7) is likely to cause liquid leakage after box making and filling with the liquid of the contents.

  Alternatively, when the moisture (5) evaporates, there is a risk of causing a rapid volume expansion and causing a defect called bubbling. Bubbling may also lead to poor appearance and liquid leakage.

  FIG. 3 is a partial cross-sectional schematic diagram for explaining how moisture contained in a paper base material is released when a laminate constituting a liquid paper container according to the present invention is sprayed with hot air.

  The example shown in FIG. 3 is an example of a laminated body (10) constituting the liquid paper container according to the present invention. As shown in (E), the outermost thermoplastic resin layer (2) is provided in stripes. Incidentally, the innermost thermoplastic resin layer (3) is provided on the entire surface.

  When performing box making by heat sealing, as shown in (G), heat sealing is performed after spraying hot air (6) from the inside of the container.

  Subsequently, as shown in (H), the moisture (5) in the heated paper base material is vaporized and tends to come out from the paper base material. At this time, since the outermost thermoplastic resin layer (2) is provided in a stripe shape, the surface of the paper substrate is exposed in the gap between the stripes, and the moisture (5) becomes water vapor. It becomes possible to go out of the laminate.

  At the stage where the heating with the hot air (6) is finished, as shown in (I), the moisture (5) contained in the paper substrate decreases, and the innermost thermoplastic resin layer (3) forms a pinhole. Without being softened. Therefore, heat sealing for box making is easier and productivity is improved.

  FIG. 4 is a schematic perspective view for explaining the stripe width of the outermost thermoplastic resin layer and the gap between the stripes of the laminate constituting the body paper container according to the present invention.

  The example shown in FIG. 4 is a diagram showing the outermost thermoplastic resin layer (2), wherein the thermoplastic resin is provided in a stripe shape, the stripe width (8) applied with the thermoplastic resin, and the stripe And stripe gaps (9) are alternately arranged.

  As described above, as a result of diligent investigations in proceeding with the present invention, the outermost thermoplastic resin layer (2) provided in the stripe shape has a width of the stripe to which the thermoplastic resin is applied ( It was found that 8) should be in the range of more than 5 μm and not more than 500 μm, and the gap (9) between the stripes should be in the range of more than 5 μm and not more than 500 μm.

  That is, when the thermoplastic resin layer (2) is within this range, the liquid paper container according to the present invention does not interfere with the heat sealability when the container is manufactured using heat seal, and hot air is not disturbed. Generation of pinholes due to spraying can be prevented.

  FIG. 5 is a partial cross-sectional schematic diagram for explaining an embodiment having a gas barrier layer of a laminate constituting the liquid paper container according to the present invention, and a partial cross-sectional schematic diagram for explaining examples and comparative examples. FIG.

In the laminated body constituting the liquid paper container in the present invention, a gas barrier layer (12) is provided between the paper base material which is the base material (1) and the innermost thermoplastic resin layer (3) as necessary. Can be provided.

  The gas barrier layer (12) is intended to suppress the permeation of oxygen and moisture by its gas barrier property and further enhance the storage stability of the liquid of the contents.

In the example shown in FIG. 5, the structure of the laminate (10) is the thermoplastic resin layer (2) / printing ink layer (11) / base material (1) / intermediate polyethylene layer (13) / gas barrier from the outermost layer side. Layer (12) / thermoplastic resin layer (3)
It is.

  Hereinafter, a more detailed description will be given for each layer in this order.

<Thermoplastic resin layer (2)>
As the material of the thermoplastic resin layer (2), a polyolefin-based resin is generally used among thermoplastic resins. Specifically, a low-density polyethylene resin (LDPE), a medium-density polyethylene resin (MDPE), a straight chain Ethylene resins such as a low-density polyethylene resin (LLDPE), a high-density polyethylene (HDPE), an ethylene-vinyl acetate copolymer (EVA), and an ethylene-methacrylic acid resin copolymer can be used.

  Also, use polypropylene resins such as blend resin of polyethylene and polybutene, homopolypropylene resin (PP), propylene-ethylene random copolymer, propylene-ethylene block copolymer, propylene-α olefin copolymer, etc. Can do.

  In forming the thermoplastic resin layer (2), a molten resin can be formed using an extruder or the like, and the layer can be formed on the surface of the laminate. The present invention is characterized in that the outermost thermoplastic resin layer (2) is provided in a stripe shape.

  Therefore, for example, a comb blade-like stopper is provided in a slit portion for discharging the molten resin of the extruder, and a portion where the molten resin is applied and a portion where the base material (1) is exposed without applying the molten resin. It can be realized by alternately forming along the flow direction of the substrate.

  The thickness of the thermoplastic resin layer (2) is preferably about 10 μm to 40 μm, and the width (8) of the stripe on which the thermoplastic resin is applied is in the range of more than 5 μm to 500 μm, and the gap between the stripes ( 9) is a range of more than 5 μm and 500 μm or less.

<Printing ink layer (11)>
A printing ink layer (11) can be provided on the surface side of the substrate (1). Providing the printing ink layer (11) displays, for example, information on the contents, displays tools for information management from production of products such as barcodes to distribution and sales, and designs, logo marks, etc. The purpose is to make the product more attractive.

  The printing method is not particularly limited, and can be appropriately selected from conventional printing methods on a paper substrate, such as an offset printing method, a gravure printing method, a flexographic printing method, and an inkjet printing method.

The printing ink used for the printing ink layer (11) does not have any particular restrictions, but is an ink type adapted to the printing method and has good adhesion to the substrate (1) and the thermoplastic resin layer (2). In addition, if safety is taken into consideration when the contents are beverages, etc., it can be appropriately selected from existing ink types.

<Base material (1)>
The paper substrate, in consideration of the internal volume of the liquid packaging cartons, for example 1 liter those liquid sheet if the container 280g ^/ m ² ~380g / m 2 about a basis weight available, 2 liters if liquid packaging ^cartons, those 350g / ^{m 2} ~450g / m 2 about a basis weight can be suitably used as a substrate (1).

<Intermediate polyethylene layer (13)>
An intermediate polyethylene layer (13) is provided on the back side of the substrate (1), and is provided for the purpose of adhering and laminating both layers between the substrate (1) and the gas barrier (12) layer. it can.

  Specifically, a low density polyethylene resin (LDPE), a medium density polyethylene resin (MDPE), or a linear low density polyethylene resin (LLDPE) can be used as the intermediate polyethylene layer. An ethylene-vinyl acetate copolymer Copolymers such as (EVA) and ethylene-methacrylic acid resin copolymers can be used.

  The thickness of the intermediate polyethylene layer (13) is preferably about 10 to 40 μm, and a layer can be formed using an extruder to constitute a part of the laminate (10).

<Gas barrier layer (12)>
The gas barrier layer (12) is intended to suppress the permeation of oxygen and moisture by its gas barrier property and further enhance the storage stability of the liquid of the contents.

  For example, a metal foil such as aluminum can be used as the gas barrier layer (12). Alternatively, a gas barrier film in which a gas barrier layer made of a metal such as aluminum, a metal oxide, an inorganic compound, or the like is deposited on the surface of the plastic film can be used. In any case, it is effective for improving the storage stability of the contents.

  When an aluminum foil is used as the gas barrier layer (12), a thickness in the range of 6 μm to 25 μm can be suitably used.

  In the case of a gas barrier film, the plastic film to be used is not particularly limited, but for example, when polypropylene or polyethylene terephthalate is used as a plastic film substrate, it is more preferable in terms of film strength and price.

  Moreover, when using a polyamide film for the plastic film base material of a gas barrier layer (12), mechanical toughness can be provided. The said plastic film can use the thing of the range of 6 micrometers-25 micrometers suitably.

  In the case of a gas barrier film, the gas barrier layer (12) can be composed of, for example, an inorganic compound vapor-deposited layer and a coating layer, and can be constructed by sequentially providing a vapor-deposited layer and a coating layer after providing an anchor coat on a plastic film. Is possible.

  As a method for forming a vapor deposition layer, an inorganic compound such as SiO or AlO can be coated on a plastic film provided with an anchor coat layer using a vacuum vapor deposition method to form an inorganic compound layer by a vacuum vapor deposition method. .

As a method for forming the coating layer, an aqueous solution or water / alcohol containing at least one of a water-soluble polymer and (a) one or more alkoxides or hydrolysates thereof, or (b) tin chloride. A coating agent mainly composed of a mixed aqueous solution is applied onto a film and dried by heating to form an inorganic compound layer by a coating method to form a coating layer.

  At this time, the adhesion with the anchor coat layer can be improved by adding a silane monomer to the coating agent.

  An inorganic compound layer has a gas barrier property only by a coating film formed by a vacuum deposition method, but a gas barrier layer is formed by overlaying a coating layer that is an inorganic compound layer formed by a coating method on a deposited layer that is an inorganic compound layer formed by a vacuum deposition method. It can be.

  Therefore, since the gas barrier film has higher gas barrier properties, moisture resistance, and water resistance, and is flexible enough to withstand deformation due to external force, it can also be suitable as a liquid paper container.

<Thermoplastic resin layer (3)>
A thermoplastic resin layer (3) is provided as a sealant layer on the innermost layer side of the laminate (10) constituting the liquid container.

  As a material of the thermoplastic resin layer (3), a polyolefin-based resin is generally used among thermoplastic resins, and specifically, a low density polyethylene resin (LDPE), a medium density polyethylene resin (MDPE), a straight chain. A copolymer such as a low-density polyethylene resin (LLDPE), a high-density polyethylene (HDPE), an ethylene-vinyl acetate copolymer (EVA), or an ethylene-methacrylic acid resin copolymer can be used.

  Also, use polypropylene resins such as blend resin of polyethylene and polybutene, homopolypropylene resin (PP), propylene-ethylene random copolymer, propylene-ethylene block copolymer, propylene-α olefin copolymer, etc. Can do.

  For forming the thermoplastic resin layer (3), a molten resin can be formed using an extruder or the like to form a layer on the surface of the laminate. Or it is also possible to form a thermoplastic resin layer (3) on the surface of a laminated body by laminating | stacking the material currently formed into the film state by lamination. Further, the thermoplastic resin layer (3) may be formed by stacking a plurality of layers.

  As described above, according to the present invention, in making a liquid paper container, it is possible to provide a liquid paper container free from liquid leakage by preventing bubbling or pinholes due to hot air heating without causing a decrease in sealing strength. Can be made possible.

  Hereinafter, the present invention will be described in more detail with reference to Examples 1 to 3 and Comparative Examples 1 to 4. However, the present invention is not limited to the examples shown here. The invention is limited only by the following claims.

  FIG. 5 is a partial cross-sectional schematic diagram for explaining an embodiment having a gas barrier layer of a laminate constituting the liquid paper container according to the present invention, and a partial cross-sectional schematic diagram for explaining examples and comparative examples. FIG.

As samples for evaluation, various laminates of Examples 1 to 3 and Comparative Examples 1 to 4 were prepared and boxed in a liquid paper container.
Liquid paper container:
It is a gobeltop type paper container, and the trunk is 85mm square. The capacity was 1 liter.
Box making:
When the box was made using the existing liquid paper container device, the box was made at a hot air temperature of 340 ° C.
Contents:
Filled with water.
Evaluation number:
n = 100.

<Evaluation items and evaluation methods>
1. Liquid mole check:
The liquid leakage after filling was confirmed.
When there was no total (100) liquid leakage, it was rated as “O”.
Otherwise, it was set as x evaluation.

2. Drop test:
The container was dropped and the container was destroyed, and it was confirmed that there was no liquid leakage.
Drop height: 80cm
Number of drops: 10 was dropped once, and the container was destroyed.
Otherwise, it was set as x evaluation.

<Example 1>
The layer structure of the laminate (10) is as follows.
From the outermost layer side, thermoplastic resin layer (2) / printing ink layer (11) / base material (1) / intermediate polyethylene layer (13) / gas barrier layer (12) / thermoplastic resin layer (3)
It is.

Thermoplastic resin layer (2): LDPE thickness 20μm
Stripe width (8): 10 μm
Stripe-to-strip gap (9): 10 μm
Base material (1): 400 g / m ²
Intermediate polyethylene layer (13): LDPE thickness 30μm
Gas barrier layer (12): SiOx-deposited polyethylene terephthalate film (thickness: 12 μm)
Thermoplastic resin layer (3): LLDPE The thickness was 60 μm.

<Example 2>
Thermoplastic resin layer (2): LDPE thickness 20μm
Stripe width (8): 100 μm (this part is different from Example 1)
Stripe-to-strip gap (9): 100 μm (this part is different from Example 1)
Base material (1): 400 g / m ²
Intermediate polyethylene layer (13): LDPE thickness 30μm
Gas barrier layer (12): SiOx-deposited polyethylene terephthalate film (thickness: 12 μm)
Thermoplastic resin layer (3): LLDPE The thickness was 60 μm.

<Example 3>
Thermoplastic resin layer (2): LDPE thickness 20μm
Stripe width (8): 500 μm (this part is different from Example 1)
Stripe-to-strip gap (9): 500 μm (this part is different from Example 1)
Base material (1): 400 g / m ²
Intermediate polyethylene layer (13): LDPE thickness 30μm
Gas barrier layer (12): SiOx-deposited polyethylene terephthalate film (thickness: 12 μm)
Thermoplastic resin layer (3): LLDPE The thickness was 60 μm.

<Comparative Example 1>
Thermoplastic resin layer (2): LDPE thickness 20μm
Stripe width (8): None. Planar (this part is different from the first embodiment)
Stripe-to-strip gap (9): None. Planar (this part is different from the first embodiment)
Base material (1): 400 g / m ²
Intermediate polyethylene layer (13): LDPE thickness 30μm
Gas barrier layer (12): SiOx-deposited polyethylene terephthalate film (thickness: 12 μm)
Thermoplastic resin layer (3): LLDPE The thickness was 60 μm.

<Comparative example 2>
Thermoplastic resin layer (2): LDPE thickness 20μm
Stripe width (8): 5 μm (this part is different from Example 1)
Stripe-to-strip gap (9): 10 μm
Base material (1): 400 g / m ²
Intermediate polyethylene layer (13): LDPE thickness 30μm
Gas barrier layer (12): SiOx-deposited polyethylene terephthalate film (thickness: 12 μm)
Thermoplastic resin layer (3): LLDPE The thickness was 60 μm.

<Comparative Example 3>
Thermoplastic resin layer (2): LDPE thickness 20μm
Stripe width (8): 10 μm
Stripe-to-strip gap (9): 5 μm (this part is different from Example 1)
Base material (1): 400 g / m ²
Intermediate polyethylene layer (13): LDPE thickness 30μm
Gas barrier layer (12): SiOx-deposited polyethylene terephthalate film (thickness: 12 μm)
Thermoplastic resin layer (3): LLDPE The thickness was 60 μm.

<Comparative example 4>
Thermoplastic resin layer (2): LDPE thickness 20μm
Stripe width (8): 500 μm (this part is different from Example 1)
Stripe-to-strip gap (9): 520 μm (this part is different from Example 1)
Base material (1): 400 g / m ²
Intermediate polyethylene layer (13): LDPE thickness 30μm
Gas barrier layer (12): SiOx-deposited polyethylene terephthalate film (thickness: 12 μm)
Thermoplastic resin layer (3): LLDPE The thickness was 60 μm.

<Comparative Example 5>
Thermoplastic resin layer (2): LDPE thickness 20μm
Stripe width (8): 520 μm (this part is different from Example 1)
Stripe-to-strip gap (9): 500 μm (this part is different from Example 1)
Base material (1): 400 g / m ²
Intermediate polyethylene layer (13): LDPE thickness 30μm
Gas barrier layer (12): SiOx-deposited polyethylene terephthalate film (thickness: 12 μm)
Thermoplastic resin layer (3): LLDPE The thickness was 60 μm.

  The evaluation results are shown in Table 1.

  From the results shown in Table 1, both of the evaluation items in the Examples 1 to 3 according to the present invention are evaluated as “O”. On the other hand, in Comparative Examples 1 to 5, where the presence or absence of a stripe, the width (8) of the stripe, or the gap (9) between the stripes deviated from the scope of the present invention, any of the evaluation items Was evaluated as x, and the superiority of Examples 1 to 3 according to the present invention was clarified.

  In Example 1, the stripe width (8) is 10 μm, and the stripe-to-stripe gap (9) is 10 μm, which is within the scope of the present invention, and is evaluated as “Good” in the liquid leakage and drop tests.

  In Example 2, the stripe width (8) is 100 μm and the stripe-to-stripe gap (9) is 100 μm, which is within the scope of the present invention, and is evaluated as “good” in the liquid leakage and drop tests.

  In Example 3, the stripe width (8) is 500 μm and the stripe-to-stripe gap (9) is 500 μm, which is within the scope of the present invention, and is evaluated as “good” in the liquid leakage and drop tests.

  In Comparative Example 1, since the thermoplastic resin layer (2) was not provided with stripes, pinholes were generated and liquid leakage was observed.

  In Comparative Example 2, the gap (9) between the stripes was 5 μm, which was below the range of the present invention, and liquid leakage was observed due to the generation of pinholes.

  In Comparative Example 3, the stripe width (8) was 5 μm, which was below the range of the present invention. In the drop test, the container was broken due to insufficient strength of the seal portion of the liquid paper container, and liquid leakage was observed.

  In Comparative Example 4, the stripe width (8) was 520 μm, which exceeded the range of the present invention, pinholes were generated, and liquid leakage was observed.

  In Comparative Example 5, the stripe-to-strip gap (9) is 520 μm, which is beyond the range of the present invention. In the drop test, the container was destroyed due to insufficient strength of the seal portion of the liquid paper container, and liquid leakage was observed. It was.

Thus, according to the present invention, it is possible to provide a liquid paper container free from liquid leakage by preventing bubbling or pinholes due to hot air heating without reducing the sealing strength in the case of making a liquid paper container. We were able to verify that it was possible.

DESCRIPTION OF SYMBOLS 1 ... Base material 2 ... Thermoplastic resin layer 3 ... Thermoplastic resin layer 4 ... Stripe 5 ... Moisture 6 ... Hot air 7 ... Pinhole 8 ... Stripe Width 9 ... Stripe-to-stripe gap 10 ... Laminate 11 ... Printing ink layer 12 ... Gas barrier layer 13 ... Intermediate polyethylene layer

Claims (3)

It is a liquid paper container consisting of a laminate having a thermoplastic resin layer as an innermost layer and an outermost layer, using paper as a base material,
The outermost thermoplastic resin layer is provided in stripes using an extruder,
The thermoplastic resin provided in a stripe shape has a width of the portion to which the thermoplastic resin is applied in a range of more than 5 μm and 500 μm or less,
A liquid paper container, wherein a gap between stripes is in a range of more than 5 μm and not more than 500 μm.   The liquid paper container according to claim 1, wherein the thermoplastic resin layer is made of polyethylene resin.   The liquid paper container according to claim 1, wherein a gas barrier layer is provided between the paper base material and the innermost thermoplastic resin layer.

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