JP2022118071A - packaging material - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a packaging material which can suppress adsorption of a component contained in contents (non-adsorption), can suppress the transfer of the odor of the adhesive layer to the contents (non-permeable), and can suppress generation of bubbling in heating when a heat-fusion part of the packaging material is thermally compression bonded.

SOLUTION: A packaging material 100 at least includes a thermoplastic resin layer 110, a paper base material layer 120, a first adhesive resin layer 130, a barrier layer 140, and a heat-fusible resin layer 160 containing a resin made of a cyclic olefin copolymer in this order, in which the paper base material layer is a paper base material layer having a density of 0.780 g/cm³ or more and 0.850 g/cm³ or less.

SELECTED DRAWING: Figure 2

COPYRIGHT: (C)2022,JPO&INPIT

Description

TECHNICAL FIELD The present invention relates to a packaging material, and more particularly to a packaging material for packaging alcoholic beverages such as sake, shochu and wine, liquid beverages such as coffee, juice and milk, and liquid foods such as soup, soup stock and mentsuyu.

Conventionally, packaging materials used for packaging containers for packaging contents such as alcoholic beverages, liquid beverages, and liquid foods include a paper base layer and a gas barrier such as oxygen and water vapor to improve the storage stability of the contents. It is widely known that a laminate is used in which a barrier layer provided with and a heat-fusible resin layer made of a heat-fusible resin are laminated. However, polyethylene resin is generally used for the side of the heat-fusible resin layer that comes into contact with the contents because of its excellent sealability.

However, since polyethylene resin is used for the innermost surface in contact with the content of the heat-sealable resin layer, some of the components contained in the content may be adsorbed by the polyethylene resin. There is a problem that the flavor of ginjo sake is impaired due to the adsorption of the aromatic components. On the other hand, the odor of the adhesive layer interposed between the barrier layer and the heat-fusible resin layer permeates the polyethylene resin layer of the innermost heat-fusible resin layer and migrates to the contents, resulting in a decrease in the taste of the contents. There is a problem.

In order to solve such problems, a liquid paper container having at least a thermoplastic resin layer on the front surface and at least a gas barrier layer and a sealant layer (also referred to as a heat-fusible resin layer) on the back surface, wherein the sealant layer A configuration has been proposed in which a cyclic olefin resin layer is used on the surface with which the contents of the container come into contact (see, for example, Patent Document 1). The cyclic olefin resin suppresses the adsorption of some of the components contained in the contents (hereinafter referred to as non-adsorption), and suppresses the transfer of the odor of the adhesive layer to the contents (hereinafter referred to as non-adsorption). permeation). Patent Document 1 discloses a paper container for liquid that is non-adsorbent and non-permeable because a cyclic olefin-based resin layer is used on the surface that comes into contact with the contents.

JP 2012-86856 A

However, the packaging material used for the liquid paper container described in Patent Document 1 uses a cyclic olefin resin on the inner surface of the sealant layer, so compared to conventional packaging materials using polyethylene resin on the inner surface, the sealant layer When the sealant layer is heated, the air contained in the paper base layer expands, or the moisture evaporates and expands, causing the paper base layer to expand. There is a problem that air bubbles are generated (hereinafter referred to as bubbling) between the layer and the barrier layer. In particular, in the case of paper containers for liquids, bubbling is more likely to occur because both the inner and outer surfaces of the packaging material are heated simultaneously.

Accordingly, the present invention has been made to solve the above problems, and its object is to suppress the adsorption of the components contained in the contents (non-adsorbability), and to transfer the odor of the adhesive layer to the contents. The object of the present invention is to provide a packaging material capable of suppressing (non-permeable) the occurrence of bubbling during heating when the heat-sealed portion of the packaging material is thermocompression-bonded.

In order to achieve the above object, the present invention according to claim 1 includes, in order, at least a thermoplastic resin layer, a paper base layer, an adhesive resin layer, a barrier layer, and a resin consisting of a cyclic olefin copolymer. A packaging material comprising a heat-fusible resin layer, wherein the paper base layer is a paper base having a density of 0.780 g/cm ³ or more and 0.850 g/cm ³ or less. is.

Further, the present invention according to claim 2 is the packaging material according to claim 1, wherein the heat-fusible resin layer comprises at least a polyolefin resin layer and a first cyclic olefin copolymer in order from the barrier layer side. A resin layer and a second cyclic olefin copolymer resin layer, wherein the first cyclic olefin copolymer resin layer contains 80% by mass or more of the resin made of the cyclic olefin copolymer, and the second cyclic The olefin copolymer resin layer is characterized by containing 10% by mass or more and 80% by mass or less of the resin composed of the cyclic olefin copolymer.

According to a third aspect of the present invention, in the packaging material according to the first or second aspect, the adhesive resin layer has a thickness of 15 μm or more and 50 μm or less.

Further, the present invention according to claim 4 is the packaging material according to any one of claims 1 to 3, wherein the barrier layer is a metal foil or a resin film on one side of which an inorganic oxide or metal is vapor-deposited. It is characterized by being a deposited film having a deposited layer.

Further, according to the present invention of claim 5, in the packaging material according to any one of claims 2 to 4, the polyolefin resin layer provided on the barrier layer side of the heat-fusible resin layer comprises at least It is characterized by comprising a polyethylene resin layer and a linear low-density polyethylene resin layer.

The packaging material of the present invention uses a heat-sealable resin layer made of a cyclic olefin copolymer on the surface that comes into contact with the contents, so that adsorption of the components contained in the contents can be suppressed (non-adsorptive). In addition, since the odor of the adhesive layer can be suppressed (impermeable) from transferring to the contents, it is possible to prevent the taste of the contents from being spoiled. In addition, when the heat-sealed portion of the packaging material is thermocompression-bonded, it is possible to suppress the occurrence of bubbling during heating.

1 is a perspective view showing an embodiment of a packaging container using the packaging material according to the present invention; FIG. BRIEF DESCRIPTION OF THE DRAWINGS It is a schematic sectional drawing which shows the layer structure of the packaging material which concerns on 1st Embodiment of this invention. FIG. 5 is a schematic cross-sectional view showing the layer structure of a packaging material according to a second embodiment of the present invention; FIG. 10 is a schematic cross-sectional view showing the layer structure of a packaging material according to a third embodiment of the present invention; Fig. 2 is a perspective view showing a state in which a paper container for liquid using the packaging material according to the present invention has been put up into a cylindrical shape from a state in which it has been folded and stuck to the body before completion of assembly. Fig. 2 is a perspective view showing a crooked state before heating of the top portion of the paper container for liquid using the packaging material according to the present invention before completion of assembly; It is an explanatory view explaining a heating part for top parts of an apparatus main part provided with a chamber part.

The present invention described above will be described in detail below with reference to the drawings and the like.
FIG. 1 is a perspective view showing one embodiment of a packaging container using the packaging material according to the present invention, FIG. 2 is a schematic cross-sectional view showing the layer structure of the packaging material according to the first embodiment of the present invention, and FIG. FIG. 4 is a schematic cross-sectional view showing the layer structure of the packaging material according to the second embodiment of the invention, FIG. 4 is a schematic cross-sectional view showing the layer structure of the packaging material according to the third embodiment of the invention, and FIG. Fig. 6 is a perspective view showing a state in which a paper container for liquid using the material is put into a cylindrical shape from a state in which the paper container for liquid has been folded and stuck to the body before completion of assembly; Fig. 7 is a perspective view showing a crooked state before heating of the top portion before completion of assembly, and Fig. 7 is an explanatory view for explaining the heating portion for the top portion of the main body of the apparatus provided with the chamber portion, in which 100, 200, 300 Packaging material 110 is a thermoplastic resin layer, 120 is a paper base layer, 130 is an adhesive resin layer, 140 is a barrier layer, 141 is a resin film, 142 is a vapor deposition layer, 150 is an adhesive layer, and 160 is a heat-fusible resin. Layers 161 is a polyolefin resin layer, 161a is a polyethylene resin layer, 161b is a linear low-density polyethylene resin layer, 162 is a first cyclic olefin copolymer resin layer, and 163 is a second cyclic olefin copolymer resin layer. , 10 is a paper container for liquid, 10' is a paper container for liquid before assembly is completed, 11 is a heat-sealed body portion, 12 is a heat-sealed top portion, 13 is an outlet portion, 14 is an open top end portion, and 14' is a 15 is the opening bottom end, 16 is the hole portion, 17 is the top portion, 18 is the bottom portion, 20 is the chamber portion, 21 is the outer heating portion, and 22 is the inner heating portion.

[First embodiment]
FIG. 1 is a perspective view showing an embodiment of a packaging container using the packaging material according to the present invention, showing an example of a paper container 10 for liquid.

The paper container for liquid 10 is in a developed state (hereinafter referred to as a blank) obtained by punching a packaging material 100 (see FIG. 2) into a predetermined contour shape with a punching die having predetermined ruled lines and cutting edges. Then, the edges of the folded blank are overlapped along the ruled line to form a body heat-sealed portion 11 having a predetermined width, the body heat-sealed portion 11 is formed into a cylindrical shape by, for example, frame sealing, and then the bottom is heat-sealed by a filling machine. It shows a gable-top container formed into a box shape by heat-pressing a bonding portion (not shown) and a top heat-sealed portion 12 . The body heat-sealed portion 11, the top heat-sealed portion 12, and the bottom heat-sealed portion are formed by heat-sealing the innermost heat-sealable resin layer 160 (see FIG. 2) of the packaging material 100 so as to face each other. be. Although the top heat-sealed portion 12 is visible in FIG. 1, the body heat-sealed portion 11 is provided in a strip shape at one corner in the vertical direction in FIG. Since it is not visible, it is indicated by a dashed line, and the bottom heat seal is not shown. The liquid paper container 10 is filled with alcoholic beverages such as sake and shochu, liquid beverages such as juice, tea, water, coffee, and milk drinks, and liquid foods such as soup, which are not shown, and sealed. A spout portion 13 having a spout main body and a cap is provided on the top portion 17 of the container so that the contents can be easily poured out in use. Although not shown, the outer surface of the thermoplastic resin layer 110 (see FIG. 2), which is the outer side, is usually printed by gravure printing, offset printing, flexographic printing, or the like.

FIG. 2 is a schematic cross-sectional view showing the layer structure of the packaging material 100 according to the first embodiment of the present invention.
The packaging material 100 comprises, in order, at least a thermoplastic resin layer 110, a paper base layer 120, an adhesive resin layer 130, a barrier layer 140, and a heat-fusible resin layer 160 containing a resin made of a cyclic olefin copolymer. be. Also, the barrier layer 140 and the heat-fusible resin layer 160 are laminated with the adhesive layer 150 interposed therebetween. The adhesive layer 150 is provided as required.

As shown in FIG. 2, the heat-sealable resin layer 160 includes at least a polyolefin resin layer 161, a first cyclic olefin copolymer resin layer 162, and a second cyclic olefin copolymer resin layer in order from the barrier layer 140 side. 163 is provided. The heat-fusible resin layer 160 only needs to contain a resin made of a cyclic olefin copolymer, and is not limited to the structure shown in FIG. 2, but is a preferred embodiment.

Next, each layer constituting the packaging material 100 will be described.
For the paper base layer 120, a milk carton base paper, a cup base paper, a paperboard, or the like having formability, bending resistance, rigidity, stiffness, strength, etc. is used in order to make the liquid paper container 10 rigid, and the density of the paper is It is characterized by being 0.780 g/cm ³ or more and 0.850 g/cm ³ or less. By defining the density of the base paper used for the paper base layer 120, even the heat-fusible resin layer 160 containing a resin made of a cyclic olefin copolymer can be heated and press-bonded at the heat-sealed portion, as will be described later. , the occurrence of bubbling can be suppressed. If the density of the base paper is less than ^0.780 g/cm ³ , the rigidity, stiffness, and strength are insufficient, and a rigid paper container 10 for liquid cannot be obtained. Air contained in the base paper of the paper base layer expands when the part is heated, or air bubbles generated by evaporation and expansion of moisture become difficult to escape to the outside through the paper base layer 120, and bubbling is prevented. more likely to occur. Also, the basis weight of base paper used is about 100 to 450 g/m ² .

The thermoplastic resin layer 110 formed on the upper surface of the paper base layer 120 imparts water resistance to the liquid paper container 10, and heat-seales the thermoplastic resin layers 110 facing each other. is used, mainly low-density polyethylene. The thermoplastic resin layer 110 is laminated onto the paper base layer 120 by hot melt extrusion of low density polyethylene. Since the surface of the thermoplastic resin layer 110 is usually printed, it is preferable to apply a surface treatment such as corona discharge treatment in order to improve the adhesiveness of the printing ink.

The adhesive resin layer 130 is a resin layer that bonds the paper base layer 120 and the barrier layer 140 by extrusion lamination, co-extrusion lamination, or the like. Resins used in the extrusion lamination method and co-extrusion lamination method include low-density polyethylene, ionomer, ethylene-acrylic acid copolymer (EAA), ethylene-methacrylic acid copolymer (EMAA), ethylene-methyl acrylate copolymer. Resins such as coalescence (EMA), ethylene-ethyl acrylate copolymer (EEA), ethylene-methyl methacrylate copolymer (EMMA) are used.

The thickness of the adhesive resin layer 130 is preferably 15 μm or more and 50 μm or less. If the thickness is less than 15 μm, the adhesive strength between the paper base layer 120 and the barrier layer 140 is insufficient, and if the thickness exceeds 50 μm, molding failure occurs when forming a liquid paper container by a liquid paper container filling and sealing device. easier.

The barrier layer 140 has gas barrier properties and prevents oxygen and water vapor from permeating the packaging material 100 from the outside and entering the paper container 10 for liquid. It plays a role of preventing, for example, the aroma component of the substance from penetrating the packaging material 100 and escaping to the outside of the liquid paper container 10 . The barrier layer 140 has, for example, a deposition layer 142 (see FIG. 3) formed by depositing a metal such as aluminum, silicon oxide, or aluminum oxide on a resin film 141 (see FIG. 3) such as polyethylene terephthalate film or nylon film. A film or a metal foil such as aluminum can be used. The aluminum foil imparts gas barrier properties and functions such as light shielding properties, and soft, semi-hard, hard or alloy type aluminum foil having a thickness of 5 to 20 μm is used. When a vapor deposition film is used as the barrier layer 140, the vapor deposition layer 142 is laminated so as to be positioned on the adhesive resin layer 130 side.

The adhesive layer 150 is provided as necessary to bond the barrier layer 140 and the heat-fusible resin layer 160 together. The adhesive layer 150 is formed by a dry lamination method or an extrusion lamination method using a urethane-based two-liquid curing adhesive or an adhesive resin. As the adhesive resin, the same resin as the adhesive resin layer 130 can be used.

It is preferable that the heat-fusible resin layer 160 contains a resin made of a cyclic olefin copolymer. Examples of the cyclic olefin copolymer include random copolymers of ethylene/cyclic olefin copolymers, hydrides of ring-opened copolymers of cyclic olefin copolymers, and random graft-modified ethylene/cyclic olefin copolymers. Examples thereof include ring-opening copolymers of cyclic olefin copolymers that are coalesced or graft-modified. Specific examples of resins made of cyclic olefin copolymers include TOPAS (registered trademark) manufactured by Polyplastics Co., Ltd., APEL (registered trademark) manufactured by Mitsui Chemicals, Inc., ZEONOR (registered trademark) manufactured by Nippon Zeon Co., Ltd., and ZEONEX. (registered trademark).

The heat-fusible resin layer 160 may be a single layer made of a cyclic olefin resin, but preferably a multilayer of two or more layers. As shown in FIG. 2, the heat-fusible resin layer 160 includes at least a polyolefin resin layer 161, a first cyclic olefin copolymer resin layer 162, and a second cyclic olefin copolymer resin layer in order from the adhesive layer 150 side. 163. As the polyolefin resin for the polyolefin resin layer 161, low-density polyethylene, medium-density polyethylene, high-density polyethylene, linear low-density polyethylene, and polypropylene can be used, and polyethylene-based resin is preferable. The first cyclic olefin copolymer resin layer 162 contains 80% by mass or more of a cyclic olefin copolymer resin, and the second cyclic olefin copolymer resin layer 163 contains a cyclic olefin copolymer resin. It is preferable to contain 10% by mass or more and 80% by mass or less. These three layers of polyolefin resin layer 161, first cyclic olefin copolymer resin layer 162, and second cyclic olefin copolymer resin layer 163 can be coextruded and used as a coextruded film. The total thickness of the heat-fusible resin layer 160 is about 30 μm or more and 80 μm or less.

The polyolefin resin layer 161 that constitutes the heat-fusible resin layer 160 is a layer for increasing the strength of lamination with the barrier layer 140 or the adhesive layer 150. The first cyclic olefin copolymer resin layer 162 and the second cyclic By containing the cyclic olefin copolymer, the olefin copolymer resin layer 163 prevents the components of the adhesive layer 150 from migrating to the liquid paper container 10 and prevents the components of the contents from transferring to the heat-sealable resin layer 160 . Prevent adsorption. Therefore, the quality of the contents can be maintained, and particularly when the contents are liquid, the adsorption of the aromatic components can be prevented, and the taste of the contents can be favorably maintained. Thus, the cyclic olefin copolymer resin has non-adsorptive and non-permeable properties. On the other hand, when heat-sealing the trunk heat-sealed portion 11, the top heat-sealed portion 12, and the bottom heat-sealed portion, the heat-sealing temperature of the cyclic olefin copolymer resin needs to be higher than that of the low-density polyethylene. be. Therefore, the content of the cyclic olefin copolymer contained in the first cyclic olefin copolymer resin layer 162 is increased to improve non-adsorptivity and non-permeability, and the second cyclic olefin copolymer resin layer 163 By making the content of the cyclic olefin copolymer contained in the first cyclic olefin copolymer resin layer 162 less than the content of the cyclic olefin copolymer contained in the first cyclic olefin copolymer resin layer 162, while having non-adsorbing and non-permeable properties It is possible to suppress an increase in the heat-sealing temperature and widen the selection range of the temperature for heat-pressing. In other words, by controlling the content of the cyclic olefin copolymer resin, the non-adsorptive effect of the cyclic olefin copolymer and the property that the heat-sealing temperature is higher than that of low-density polyethylene. and heat-sealability can be compatible.

[Second embodiment]
< Figure 3 >It is the outline cross section diagram which shows the layer constitution of the packaging material 200 which relates to the 2nd execution form of this invention. In the packaging material 200 of the second embodiment, the barrier layer 140 is a vapor-deposited film having a vapor-deposited layer 142 in which an inorganic oxide or metal is vapor-deposited on one side of a resin film 141, and the rest is the same as the first embodiment. Since they are similar, they are denoted by the same reference numerals and their description is omitted. Note that the vapor deposition layer 142 of the barrier layer 140 is preferably arranged on the adhesive resin layer 130 side.

[Third Embodiment]
FIG. 4 is a schematic cross-sectional view showing the layer structure of the packaging material 300 according to the third embodiment of the invention. The packaging material 300 of the third embodiment is the same as that of the first embodiment except for the configuration of the heat-fusible resin layer 160, and thus the same reference numerals are given and the description thereof is omitted. The heat-fusible resin layer 160 of the packaging material 300 includes at least a polyolefin resin layer 161, a first cyclic olefin copolymer resin layer 162, and a second cyclic olefin copolymer resin layer 163 in this order from the adhesive layer 150 side. The polyolefin resin layer 161 provided on the adhesive layer 150 side consists of two layers, and includes at least a polyethylene resin layer 161a and a linear low-density polyethylene resin layer 161b. The polyethylene resin layer 161a is arranged on the adhesive layer 150 side, and the linear low-density polyethylene resin layer 161b is arranged on the first cyclic olefin copolymer resin layer 162 side.

The polyethylene resin layer 161a of the polyolefin resin layer 161 may be made of low-density polyethylene, medium-density polyethylene, or high-density polyethylene. The linear low-density polyethylene resin layer 161 b arranged on the side of the first cyclic olefin copolymer resin layer 162 adheres well to the first cyclic olefin copolymer resin layer 162 . Also, the low-density polyethylene of the polyethylene resin layer 161a adheres well to the linear low-density polyethylene resin layer 161b. Therefore, by making the polyolefin resin layer 161 multi-layered in this way, the interlayer adhesion between each layer and the adjacent layer is improved, and the adhesion strength obtained by heat-sealing the heat-sealable resin layers 160 of the liquid paper container 10 is increased. can be high.

Next, in order to deepen the understanding of the state in which bubbling occurs, the state in which the top heat-sealed portion 12 is heat-sealed will be described with reference to FIGS.

First, the assembly of the liquid paper container 10 will be described. In order to assemble the liquid paper container 10 as shown in FIG. 1 from a blank (not shown) punched out into a predetermined shape by applying creasing lines to the packaging material, a substantially rectangular blank is folded and one opposite end is attached to, for example, a frame. The body heat-sealed portion 11 is heat-sealed by sealing to be attached to the cylinder, and the cylinder is attached to the cylinder before the completion of assembly and folded flat. This is supplied to a liquid paper container filling and sealing device, and as shown in FIG. The paper container 10' for liquid before assembly is shaped into a shape, and the crease on the bottom side is first folded, heated and crimped to form the bottom, and after filling the contents from the open top end 14, the top forming plate is folded. After that, the inner surface is heated, and finally the top heat-sealed portion 12 of the top forming plate is superimposed and pressure-bonded to form the top portion of the liquid paper container 10. Assembly is completed. The spout 13 is attached to a circular hole 16 slightly larger than the outer diameter of the spout 13 at a predetermined position of the blank, for example, before the contents are filled.

FIG. 5 is a perspective view showing a state in which the paper container for liquid has been erected into a cylindrical shape from a state in which the paper container for liquid has been assembled and folded. The unassembled paper container 10' for liquid, which has been erected into a cylindrical shape, is open at both ends, and has an open top end 14 on one side and an open bottom end 15 on the other side. First, the open bottom end portion 15 is folded with a crease, heated and pressed to shape the bottom portion, and the contents are filled from the open top end portion 14 . Thereafter, as shown in FIG. 6, the top forming plate is crease-folded. Note that the spout portion 13 is omitted in FIG. 6 for the sake of simplicity.

Next, with reference to FIG. 7, the state in which the inner surface and the outer surface of the top heat-sealed portion 12 of the crimped open top end portion 14' are heated at the same time will be described. As shown in FIG. 7, the heating device main body (not shown) includes a chamber portion 20 provided with an outer surface heating portion 21 and an inner surface heating portion 22. It descends so as to cover it, heats it, and then rises and separates from the crease-folded opening top end portion 14'. During heating, the lowered chamber portion 20 covers the crooked open top end portion 14' of the paper container for liquid, and the inner surface and the outer surface of the crooked open top end portion 14' are heated by an inner surface heating portion 22 and an outer surface heating portion 21. The air heated to a predetermined temperature supplied from the hot air supply section in the main body of the apparatus is supplied from a large number of hot air injection small holes (not shown) of the outer surface heating section 21 and the inner surface heating section 22. 7, it is configured to jet hot air toward the top heat-sealed portion 12 to be bonded of the crooked opening top end 14 ′, and the inner surface of the top heat-sealed portion 12 The heat-fusible resin layer 160 and the thermoplastic resin layer 110 on the outer surface are heated and melted at the same time. After heating, the device body with the chamber portion 20 is lifted and separated from the crimped open top end 14'. Next, the gable-top liquid paper container 10 shown in FIG. 1 is completed by pressure bonding with a top pressure device (not shown) to form the top heat-sealed portion 12 . In order to pressure-bond the top heat-sealed portion 12 , hot air having a temperature of 300° C. or more is usually blown to the portion including the top heat-sealed portion 12 . At this time, the higher the temperature of the hot air, the more easily bubbling occurs. Therefore, if the heat-sealable resin layer 160 contains a cyclic olefin copolymer, the heat-sealing temperature must be increased compared to conventional low-density polyethylene, and measures to prevent bubbling are required.

However, in the packaging materials 100, 200, and 300 of the present invention, the paper base layer 120 has a density of 0.780 g/cm ³ or more and 0.850 g/cm ³ or less, so that the content of the heat-fusible resin layer 160 is reduced. Even if the side that comes into contact with an object is a cyclic olefin copolymer resin, it is possible to suppress the occurrence of bubbling in the top heat-sealed portion 12 . That is, when the top heat-sealed portion 12 is heated, the air contained in the paper base layer expands, or the air bubbles generated by the expansion due to the vaporization of water content increase the density of the paper base layer 120. This is considered to be because the paper base layer 120 functions as an air vent and escapes to the outside because it is defined within the above range. In addition, it is possible to suppress the occurrence of bubbling in the bottom heat-sealed portion as well.

It should be noted that the present invention is not limited to the above-described embodiments, and representative configuration examples are listed below.
(1) Thermoplastic resin layer 110/Paper base layer 120/Adhesive resin layer 130/Barrier layer 140/Adhesive layer 150/Heat-fusible resin layer 160 [Polyolefin resin layer 161/First cyclic olefin copolymer resin Layer 162/Second Cyclic Olefin Copolymer Resin Layer 163] <First Embodiment>
(2) Thermoplastic resin layer 110/paper substrate layer 120/adhesive resin layer 130/barrier layer 140/heat-fusible resin layer 160 [polyolefin resin layer 161/first cyclic olefin copolymer resin layer 162/second 2 cyclic olefin copolymer resin layer 163]
(3) Thermoplastic resin layer 110/paper substrate layer 120/adhesive resin layer 130/barrier layer 140/adhesive layer 150/heat-fusible resin layer 160 [polyolefin resin layer 161 (polyethylene resin layer 161a/linear low Density polyethylene resin layer 161b)/first cyclic olefin copolymer resin layer 162/second cyclic olefin copolymer resin layer 163] <Third Embodiment>
(4) Thermoplastic resin layer 110/paper base layer 120/adhesive resin layer 130/barrier layer 140/heat-fusible resin layer 160 [polyolefin resin layer 161 (polyethylene resin layer 161a/linear low-density polyethylene resin layer 161b)/first cyclic olefin copolymer resin layer 162/second cyclic olefin copolymer resin layer 163] <Third Embodiment>
(5) Thermoplastic resin layer 110/paper substrate layer 120/adhesive resin layer 130/barrier layer 140 (vapor-deposited layer 142/resin film 141)/adhesive layer 150/heat-fusible resin layer 160 [polyolefin resin layer 161/ First Cyclic Olefin Copolymer Resin Layer 162/Second Cyclic Olefin Copolymer Resin Layer 163] <Second Embodiment>
(6) Thermoplastic resin layer 110/paper base layer 120/adhesive resin layer 130/barrier layer 140 (vapor-deposited layer 142/resin film 141)/heat-fusible resin layer 160 [polyolefin resin layer 161/first annular Olefin Copolymer Resin Layer 162/Second Cyclic Olefin Copolymer Resin Layer 163]
(7) Thermoplastic resin layer 110/Paper base layer 120/Adhesive resin layer 130/Barrier layer 140 (Deposition layer 142/Resin film 141)/Adhesive layer 150/Heat-fusible resin layer 160 [Polyolefin resin layer 161 ( polyethylene resin layer 161a/linear low-density polyethylene resin layer 161b)/first cyclic olefin copolymer resin layer 162/second cyclic olefin copolymer resin layer 163]
(8) Thermoplastic resin layer 110/paper substrate layer 120/adhesive resin layer 130/barrier layer 140 (vapor-deposited layer 142/resin film 141)/heat-fusible resin layer 160 [polyolefin resin layer 161 (polyethylene resin layer 161a) /Linear low-density polyethylene resin layer 161b)/First cyclic olefin copolymer resin layer 162/Second cyclic olefin copolymer resin layer 163]

Further, the present invention will be described in detail with reference to examples.

[Example 1]
First, a polyethylene resin layer 161a with a thickness of 17.5 μm, a linear low-density polyethylene resin layer 161b with a thickness of 10 μm, a first cyclic olefin copolymer resin layer 162 with a thickness of 5 μm, a second layer with a thickness of 7.5 μm. A heat-fusible resin layer 160 containing a resin made of a cyclic olefin copolymer having a total thickness of 40 μm, in which the cyclic olefin copolymer resin layers 163 of No. 2 are laminated in order, is formed by a multi-layer inflation method to prepare a coextruded film. did. The following resins or resin compositions were used for each layer.
Polyethylene resin layer 161a: low-density polyethylene (MFR 4.0 g/10 minutes, density 0.923 g/cm ³ )
Linear low-density polyethylene resin layer 161b: Linear low-density polyethylene (MFR 2.3 g/10 minutes, density 0.914 g/cm ³ )
First cyclic olefin copolymer resin layer 162: cyclic olefin copolymer COC (manufactured by Polyplastics Co., Ltd., TOPAS)
Second cyclic olefin copolymer resin layer 163: cyclic olefin copolymer COC (manufactured by Polyplastics Co., Ltd., TOPAS) 40% by mass, linear low-density polyethylene (MFR 2.0 g/10 minutes, density 0.904 g/cm ³ ) 45% by mass, 5% by mass of low-density polyethylene (MFR 4.0 g/10 min, density 0.923 g/cm ³ ), and 10% by mass of anti-blocking agent masterbatch (EMB-21, manufactured by Sumitomo Chemical Co., Ltd.) was kneaded to prepare a resin composition.

Next, paperboard having a basis weight of 400 g/m ² and a density of 0.828 g/cm ³ was used as the paper base layer 120 , and aluminum oxide was applied to one side of a biaxially oriented polyethylene terephthalate film (PET) having a thickness of 12 μm as the barrier layer 140 . Using an aluminum oxide vapor deposited PET film (VMPET) having a vapor deposited layer (VM) of , an anchor coating agent (AC) is applied to one side of the paperboard, and an ethylene-methacrylic acid copolymer ( EMAA), the AC side of the paperboard and the VM (vapor deposited layer) of VMPET were laminated by a sandwich lamination method while extruding the EMAA to a thickness of 25 μm. Next, ethylene-methacrylic acid copolymer (EMAA) is used as the resin of the adhesive layer 150, and the polyethylene resin layer 161a surface of the coextruded film prepared as the heat-sealable resin layer 160 and the PET surface of VMPET are bonded with EMAA. It was laminated by a sandwich lamination method while being extruded to a thickness of 25 μm. Next, an anchor coating agent (AC) is applied to the other surface of the paperboard, and a low density polyethylene (LDPE) is used as the thermoplastic resin layer 110 and laminated by an extrusion coating method to a thickness of 25 μm. A packaging material was produced by applying a corona discharge treatment and printing on the corona discharge treated surface by a gravure printing method or an offset printing method to provide a printed layer. The structure of the resulting packaging material was <printed layer/LDPE 25 μm/cardboard 400 g/m ² /EMAA 25 μm/VMPET 12 μm/EMAA 25 μm/heat-fusible resin layer 40 μm>.

[Example 2]
A packaging material was produced in the same manner as in Example 1, except that a paperboard having a basis weight of 400 g/m ² and a density of 0.783 g/cm ³ was used as the paper base layer 120 .

[Example 3]
A packaging material was produced in the same manner as in Example 1, except that a paperboard having a basis weight of 410 g/m ² and a density of 0.840 g/cm ³ was used as the paper base layer 120 .

[Comparative Example 1]
A packaging material was produced in the same manner as in Example 1, except that a paperboard having a basis weight of 400 g/m ² and a density of 0.722 g/cm ³ was used as the paper base layer 120 .

[Comparative Example 2]
A packaging material was produced in the same manner as in Example 1, except that a paperboard having a basis weight of 400 g/m ² and a density of 0.855 g/cm ³ was used as the paper base layer 120 .

Using the liquid paper container packaging materials obtained in Examples 1 to 3 and Comparative Examples 1 and 2, a gable top liquid paper container with a capacity of 1.8 liters was produced, and the processability and filling suitability of the packaging material were evaluated. and the results are shown in Table 1.

The evaluation method and evaluation criteria are as follows.
[Processability]
A blank was produced by punching the packaging material with a punching machine equipped with a cutting die having predetermined ruled lines and a predetermined blank forming cutting edge. Next, while the blank was folded, one of the opposing edges was used as the trunk heat-sealed portion 11 to overlap and frame-seal.
[Bubbling state]
The state of bubbling was visually inspected for the body heat-sealed portion 11 of the paper container for liquid that had been pasted and folded into a cylindrical shape. Is there bubbling as an evaluation criterion? , No occurrence of bubbling was evaluated as ○.
[Bent state]
The lamination condition of the cylindrical folded liquid cartons was visually inspected. The evaluation criteria are comparing the width dimension of one opening side of the cylindrical folded paper container for liquid and the width dimension of the other opening side. Assuming there is a curve? and

[Filling suitability]
The folded paper container for liquid was erected and assembled by a paper container filling and sealing device equipped with a cylindrical carton assembling device or the like to produce a gable-top paper container for liquid 10 shown in FIG.
[Bubbling temperature]
The temperature of the chamber part was changed from 290° C. to 330° C. in increments of 10° C., and the temperature at which bubbling occurred was measured.
The presence or absence of bubbling was confirmed as follows. The paper container 10 for liquid shown in FIG. 1 was horizontally cut between the top portion 17 and the bottom portion 18 to divide it into upper and lower halves to obtain test samples. The top 17 and the bottom 18 of the sample to be tested were placed with the cut openings facing upward, and the test liquid was introduced through the cut openings, and the test sample was allowed to stand with the cut openings facing upward for about 1 hour. After that, a visual inspection was made to see if the test liquid had permeated the paper base layer 120 of the heat-sealed portion and colored it. What has been approved for coloring? , 0 for those without coloring, and ? was taken as the bubbling temperature. Microcheck penetrant (Ichinen Chemicals) was used as the test liquid.
[Moldability]
When the packaging material is folded along the ruled lines at the top part 17 or the bottom part 18, misalignment of folding or wrinkles caused by folding are regarded as defective molding. and Good with no molding defects was evaluated as ◯. In addition, although the frequency is low, molding defects such as misalignment, wrinkles, etc. were recognized as Δ.

As shown in Table 1, in Examples 1 to 3, good processability and filling suitability were obtained. In Comparative Example 1, bubbling was good, but bending was observed in sticking, and the workability was poor. In terms of filling aptitude, the temperature at which bubbling occurred was good at 330°C, but molding defects occurred. In Comparative Example 2, bubbling was observed in the processability, and the processability was poor. In terms of filling suitability, occurrence of bubbling was observed at 300° C., and in terms of moldability, the rigidity of the paperboard was too high, and molding defects were observed at a frequency of about 10%, which was not sufficient.

10 Paper container for liquid 10' Paper container for liquid before assembly completion 11 Body heat-sealed part 12 Top heat-sealed part 13 Spout part 14 Open top end 14' Opened top end 15 Open bottom end 16 Hole Section 17 Top Section 18 Bottom Section 20 Chamber Section 21 External Heating Section 22 Internal Heating Section 100, 200, 300 Packaging Material 110 Thermoplastic Resin Layer 120 Paper Base Layer 130 Adhesive Resin Layer 140 Barrier Layer 141 Resin Film 142 Deposition Layer 150 Adhesive Layer 160 Heat-fusible resin layer 161 Polyolefin resin layer 161a Polyethylene resin layer 161b Linear low-density polyethylene resin layer 162 First cyclic olefin copolymer resin layer 163 Second cyclic olefin copolymer resin layer

Claims (5)

A packaging material comprising, in order, at least a thermoplastic resin layer, a paper base layer, an adhesive resin layer, a barrier layer, and a heat-fusible resin layer containing a resin composed of a cyclic olefin copolymer,
The heat-fusible resin layer comprises, in order from the barrier layer side, at least a polyolefin resin layer, a first cyclic olefin copolymer resin layer, and a second cyclic olefin copolymer resin layer,
The content of the cyclic olefin copolymer contained in the second cyclic olefin copolymer resin layer is less than the content of the cyclic olefin copolymer contained in the first cyclic olefin copolymer resin layer. packaging material. The first cyclic olefin copolymer resin layer contains 80% by mass or more of the resin made of the cyclic olefin copolymer,
The packaging material according to claim 1, wherein the second cyclic olefin copolymer resin layer contains 10% by mass or more and 80% by mass or less of the resin composed of the cyclic olefin copolymer. 3. The polyolefin resin layer provided on the barrier layer side of the heat-fusible resin layer comprises at least a polyethylene resin layer and a linear low-density polyethylene resin layer. packaging material. The packaging material according to any one of claims 1 to 3, wherein the adhesive resin layer has a thickness of 15 µm or more and 50 µm or less. 5. The barrier layer according to any one of claims 1 to 4, wherein the barrier layer is a vapor-deposited film having a vapor-deposited layer in which an inorganic oxide or a metal is vapor-deposited on one surface of a metal foil or a resin film. packaging materials.

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