JP2020055275A - Packaging material - Google Patents

Abstract

To provide a packaging material which has non-adsorption and non-permeability, and can obtain a wide seal temperature range when a heat-fusion part of the packaging material is sealed.SOLUTION: A packaging material 100 includes a thermoplastic resin layer 110, a paper base material layer 120, an adhesive resin layer 130, a barrier layer 140 and a heat-fusible resin layer 150 containing an annular olefin copolymer resin, in which the heat-fusible resin layer includes a polyolefin resin layer 151, a first annular olefin copolymer resin layer 152 and a second annular olefin copolymer resin layer 153, the first annular olefin copolymer resin layer contains 80 mass% or more of an annular olefin copolymer resin, the second annular olefin copolymer resin layer contains 10 mass% or more and 80 mass% or less of the annular olefin copolymer resin, and the first annular olefin copolymer resin layer is positioned 1/2 of the total thickness of the heat-fusible resin layer from an appearance surface of the heat-fusible resin layer and is arranged at a position from 5 μm to 20 μm from the appearance surface of the heat-fusible resin layer.SELECTED DRAWING: Figure 2

Description

  The present invention relates to packaging materials, and more particularly to packaging materials for packaging alcoholic beverages such as sake, shochu, and wine, liquid beverages such as coffee, juice, and milk, and liquid foods such as soups, broths, and noodle soups.

  Conventionally, packaging materials used for packaging containers for contents such as alcoholic beverages, liquid beverages and liquid foods include a paper base layer and a gas barrier property such as oxygen and water vapor for enhancing the preservability of the contents. It is widely known that a laminate in which a barrier layer provided with a heat-fusible resin layer made of a heat-fusible resin is laminated is used. A polyethylene resin having excellent sealing properties and sealing properties is generally used on the side of the heat-fusible resin layer in contact with the contents.

  However, since the polyethylene resin is used on the innermost surface in contact with the content of the heat-fusible resin layer, some of the components contained in the content are adsorbed by the polyethylene resin, and especially in the case of Ginjo liquor, a trace amount unique to Ginjo liquor There is a problem that flavor components of Ginjo liquor are impaired due to the adsorption of aroma components of the vinegar. On the other hand, the odor of the adhesive layer interposed between the barrier layer and the heat-fusible resin layer passes through the polyethylene resin layer of the innermost heat-fusible resin layer and migrates to the contents, and the taste of the contents decreases. There is a problem.

  In order to solve such a problem, 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 (For example, refer to Patent Document 1). The cyclic olefin-based resin suppresses a part of the components contained in the content from being adsorbed (hereinafter referred to as non-adsorbent), or suppresses the odor of the adhesive layer from being transferred to the content (hereinafter referred to as non-adsorbent). It has characteristics that can be achieved. Patent Literature 1 is a liquid paper container having non-adsorptivity and non-permeability because a cyclic olefin-based resin layer is used on a surface in contact with contents.

JP 2012-86856 A

  However, the packaging material used for the liquid paper container described in Patent Literature 1 uses a cyclic olefin-based resin on the inner surface of the sealant layer, and thus has a larger sealant layer than the conventional packaging material using a polyethylene resin on the inner surface. There is a problem in that when the two members are heated and pressed to seal each other, the optimum sealing temperature range is narrow, and the management of the sealing temperature is complicated.

  Therefore, the present invention has been made to solve the above-mentioned problem, and an object of the present invention is to suppress adsorption (non-adsorption) of components contained in contents, and to transfer odor of an adhesive layer to contents. It is an object of the present invention to provide a packaging material that can suppress (impermeable) the heat-sealed portion of the packaging material and seal it by thermocompression bonding.

  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 composed of a cyclic olefin copolymer. A packaging material provided with a heat-fusible resin layer, wherein the heat-fusible resin layer has at least a polyolefin resin layer, a first cyclic olefin copolymer resin layer, and a second A cyclic olefin copolymer resin layer, wherein the first cyclic olefin copolymer resin layer contains at least 80% by mass of a resin composed of the cyclic olefin copolymer, and the second cyclic olefin copolymer resin layer Contains 10% by mass or more and 80% by mass or less of the resin made of the cyclic olefin copolymer, and the first cyclic olefin copolymer resin layer is formed by the heat-sealing in the thickness direction of the heat-fusible resin layer. sex It is located between 1/2 of the total thickness of the heat-fusible resin layer from the exposed surface of the resin layer, and at a position of 5 μm or more and 20 μm or less from the exposed surface of the heat-fusible resin layer. It is a packaging material characterized by being carried out.

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

  According to a third aspect of the present invention, in the packaging material according to the first or second aspect, the barrier layer is formed by depositing an inorganic oxide or a metal on one surface of a metal foil or a plastic film. It is a deposited film having a layer.

  According to a fourth aspect of the present invention, in the packaging material according to any one of the first to third aspects, the polyolefin resin layer provided on the side of the barrier layer of the heat-fusible resin layer has 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 can suppress the adsorption of the components contained in the contents (non-adsorptive) and suppress the transfer of the odor of the adhesive layer to the contents (non-permeable), so that the taste of the contents can be tasted. Can be prevented from being damaged. Further, when the heat-sealed portion of the packaging material is heat-pressed and sealed, a wide sealing temperature range can be obtained.

It is a perspective view showing one embodiment of a packaging container using the packaging material concerning the present invention. It is an outline sectional view showing the layer composition of the packaging material concerning a 1st embodiment of the present invention. It is an outline sectional view showing the layer composition of the packaging material concerning a 2nd embodiment of the present invention. It is an outline sectional view showing the layer composition of the packaging material concerning a 3rd embodiment of the present invention. FIG. 4 is a perspective view showing a state in which the liquid paper container using the packaging material according to the present invention is opened from the folded state and folded into a cylindrical shape before the assembly of the liquid paper container is completed. FIG. 4 is a perspective view showing a state in which the top is folded before being heated before the assembly of the liquid paper container using the packaging material according to the present invention is completed. It is explanatory drawing explaining the heating part for top parts of the apparatus main body provided with the chamber part.

The present invention will be described in detail below with reference to the drawings and the like.
FIG. 1 is a perspective view showing an embodiment of a packaging container using the packaging material according to the present invention, FIG. 2 is a schematic cross-sectional view showing a layer configuration of the packaging material according to the first embodiment of the present invention, and FIG. FIG. 4 is a schematic sectional view showing a layer structure of a packaging material according to a second embodiment of the present invention, FIG. 4 is a schematic sectional view showing a layer structure of a packaging material according to a third embodiment of the present invention, and FIG. FIG. 6 is a perspective view showing a state in which a liquid paper container using a packaging material according to the present invention is formed into a tubular shape from a folded state and a folded state before assembly of the liquid paper container using the material. FIG. 7 is a perspective view showing a state in which the top is folded before heating before assembly is completed, and FIG. 7 is an explanatory view for explaining a top heating section of the apparatus main body provided with a chamber section. Packaging material, 110 is a thermoplastic resin layer, 120 is a paper base material layer, 130 is Adhesive resin layer, 140 is a barrier layer, 141 is a resin film, 142 is a vapor deposition layer, 150 is a heat-fusible resin layer, 150s is a surface of the heat-fusible resin layer, and 150h is a total of the heat-fusible resin layer. A position at a half of the thickness, 151 is a polyolefin resin layer, 151a is a polyethylene resin layer, 151b is a linear low-density polyethylene resin layer, 152 is a first cyclic olefin copolymer resin layer, and 153 is a second Cyclic olefin copolymer resin layer, 10 is a liquid paper container, 10 'is a liquid paper container before completion of assembly, 11 is a body heat fusion part, 12 is a top heat fusion part, 13 is a spout part, and 14 is a spout part. Opening top end, 14 'is a curved top opening end, 15 is an opening bottom end, 16 is a hole, 17 is a top, 18 is a bottom, 20 is a chamber, 21 is an outer surface heating unit, 22 is an inner surface heating Parts are shown.

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

  The liquid paper container 10 is in a developed state (hereinafter, referred to as a blank) obtained by, for example, punching a packaging material 100 (see FIG. 2) into a predetermined outer shape by a punching die having predetermined ruled lines and cutting blades. One end of the blank that is folded at the ruled line is overlapped with the other end to provide a body heat-sealed portion 11 having a predetermined width, and the body heat-sealed portion 11 is formed into a tubular shape by, for example, performing frame sealing, and then forming a liquid. This figure shows a gable-top type container formed in a box shape by heat-pressing a bottom heat-sealing portion (not shown) and a top heat-sealing portion 12 with a paper container filling and sealing device. The body heat-sealing portion 11, the top heat-sealing portion 12, and the bottom heat-sealing portion are obtained by heat-sealing the innermost heat-fusible resin layer 160 (see FIG. 2) of the packaging material 100 in opposition. is there. Although the top heat-fused portion 12 is visible in FIG. 1, the body heat-fused portion 11 is provided in a band shape at one corner in the vertical direction in FIG. Since it cannot be seen, it is shown by a broken line, and the bottom heat-sealed portion is not shown. The liquid paper container 10 is filled with liquors such as sake and shochu, liquid beverages such as juice, tea, water, coffee and milk drinks, and liquid foods such as soups, which are not shown, and are sealed. The top part 17 is provided with a spout part 13 provided with a spout body and a cap so that contents and the like can be easily poured out in use. Although not shown, usually, the outer surface of the outer thermoplastic resin layer 110 (see FIG. 2) is printed by a gravure printing method, an offset printing method, a flexographic printing method, or the like.

  FIG. 2 is a schematic cross-sectional view illustrating a layer configuration of the packaging material 100 according to the first embodiment of the present invention. The packaging material 100 has a configuration including 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 150 containing a resin made of a cyclic olefin copolymer. is there.

  As shown in FIG. 2, the heat-fusible resin layer 150 includes at least a polyolefin resin layer 151, a first cyclic olefin copolymer resin layer 152, and a second cyclic olefin copolymer resin layer in this order from the barrier layer 140 side. 153 are provided. Although not shown, an adhesive layer may be provided between the barrier layer 140 and the heat-fusible resin layer 150 as needed.

  An enlarged sectional view of the heat-fusible resin layer 150 is shown in a circle in FIG. In the enlarged cross-sectional view, reference numerals indicating positions of the heat-fusible resin layer 150 are attached, 150s is the exposed surface (the surface in contact with the contents) of the heat-fusible resin layer 150, and 150h is heat-sealed. When the total thickness of the conductive resin layer 150 is T, the position is T / 2. The present invention is characterized in the positional relationship in which the first cyclic olefin copolymer resin layer 152 of the heat-fusible resin layer 150 is arranged. The first cyclic olefin copolymer resin layer 152 is の of the total thickness of the heat-fusible resin layer from the exposed surface 150s of the heat-fusible resin layer in the thickness direction of the heat-fusible resin layer 150, That is, it is located between T / 2 and at a position closer to the polyolefin resin layer 151 side from 5 μm to 20 μm from the exposed surface 150 s of the heat-fusible resin layer. Therefore, the thickness of the second cyclic olefin copolymer resin layer 153 is 5 μm or more and 20 μm or less.

Next, each layer constituting the packaging material 100 will be described.
The paper base layer 120 is made of a milk carton base paper, a cup base paper, a paperboard, or the like having moldability, bending resistance, rigidity, stiffness, strength, etc. in order to make the liquid paper container 10 rigid, and has a basis weight of 100 to 450 g. / M ² is used.

  The thermoplastic resin layer 110 formed on the upper surface of the paper base material layer 120 imparts water resistance to the liquid paper container 10 and heat-bonds the thermoplastic resin layer 110 so that the thermoplastic resin layer 110 faces the polyolefin resin. Is used, and low-density polyethylene is mainly used. The thermoplastic resin layer 110 is formed by laminating low-density polyethylene on the paper base layer 120 by a hot melt extrusion method. Since printing is usually performed on the surface of the thermoplastic resin layer 110, it is preferable to perform a surface treatment such as a corona discharge treatment in order to improve the adhesiveness of the printing ink.

  The adhesive resin layer 130 is formed of a resin layer that bonds the paper base layer 120 and the barrier layer 140 by a method such as an extrusion lamination method or a co-extrusion lamination method. Examples of the resin used in the extrusion lamination method and the coextrusion lamination method include low-density polyethylene, ionomer, ethylene-acrylic acid copolymer (EAA), ethylene-methacrylic acid copolymer (EMAA), and ethylene-methyl acrylate copolymer. Resins such as coalescing (EMA), ethylene-ethyl acrylate copolymer (EEA), and 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. When the thickness is less than 15 μm, the adhesive strength between the paper base layer 120 and the barrier layer 140 is insufficient, and when the thickness is more than 50 μm, molding failure occurs when a liquid paper container is filled with a liquid paper container filling and sealing device. It will be easier.

  The barrier layer 140 has a gas barrier property, prevents oxygen and water vapor from penetrating the packaging material 100 from the outside and entering the inside of the liquid paper container 10, and further, the contents filled in the liquid paper container 10. It plays a role in preventing, for example, an aroma component or the like of the object from permeating through the packaging material 100 and escaping to the outside of the liquid paper container 10. As the barrier layer 140, for example, a metal foil such as aluminum or a vapor-deposited film obtained by vapor-depositing a metal such as aluminum, silicon oxide, aluminum oxide, or the like on a plastic film can be used. The aluminum foil imparts functions such as gas barrier properties and light shielding properties, and a soft, semi-hard, hard or alloy type aluminum foil having a thickness of 5 to 20 μm is used.

  In the case where an adhesive layer is provided between the barrier layer 140 and the heat-fusible resin layer 150, a urethane-based two-component curable adhesive or the like or an adhesive resin is used as the adhesive layer, and when an adhesive is used, dry lamination is used. It is laminated by a method. When using an adhesive resin, lamination is performed by an extrusion lamination method or a co-press lamination method. The same resin as the adhesive resin layer 130 can be used as the adhesive resin.

  The heat-fusible resin layer 150 contains a resin made of a cyclic olefin copolymer. Examples of the cyclic olefin copolymer include, for example, an ethylene / cyclic olefin copolymer random copolymer, a hydride of a cyclic olefin copolymer ring-opening copolymer, and a graft-modified ethylene / cyclic olefin copolymer random copolymer. Examples thereof include a ring-opened copolymer of a coalesced and graft-modified cyclic olefin copolymer. Specific examples of the resin comprising a cyclic olefin copolymer include TOPAS (registered trademark) manufactured by Polyplastics Co., Ltd., APEL (registered trademark) manufactured by Mitsui Chemicals, Inc., ZEONOR (registered trademark) manufactured by Zeon Corporation, and ZEONEX. (Registered trademark).

As shown in FIG. 2, the heat-fusible resin layer 150 includes at least a polyolefin resin layer 151, a first cyclic olefin copolymer resin layer 152, and a second cyclic olefin copolymer resin in this order from the barrier layer 140 side. A layer 153 is provided. As the polyolefin resin layer 151, low-density polyethylene, linear low-density polyethylene, medium-density polyethylene, high-density polyethylene, polypropylene, or the like can be used, but polyethylene is preferable. The first cyclic olefin copolymer resin layer 152 preferably contains at least 80% by mass of a resin composed of a cyclic olefin copolymer. The second cyclic olefin copolymer resin layer 153 preferably contains 10% by mass or more and 80% by mass or less of the resin composed of the cyclic olefin copolymer.
The polyolefin resin layer 151, the first cyclic olefin copolymer resin layer 152, and the second cyclic olefin copolymer resin layer 153 may be laminated by extrusion lamination or three-layer coextrusion lamination on the barrier layer 140. Alternatively, the resin may be co-extruded to form a co-extruded film, and an adhesive resin may be extruded between the film and the barrier layer 140 and laminated by a sandwich lamination method. Alternatively, they can be laminated by a dry lamination method. The total thickness of the heat-fusible resin layer 160 is about 30 μm or more and about 80 μm or less, preferably about 40 μm or more and 60 μm or less.

  Since the first cyclic olefin copolymer resin layer 152 and the second cyclic olefin copolymer resin layer 153 contain a cyclic olefin copolymer, the components of the adhesive layer and the polyolefin resin layer 151 are transferred to the liquid paper container 10. This prevents migration and prevents the components of the contents from being adsorbed to the heat-fusible resin layer 150. Therefore, the quality of the content can be maintained, and particularly when the content is a liquid, adsorption of the fragrance component can be prevented, and the taste of the content can be favorably maintained. Thus, the cyclic olefin copolymer resin has non-adsorption and non-permeability. On the other hand, when the body heat-sealing part 11, the top heat-sealing part 12, and the bottom heat-sealing part are heat-sealed, it is necessary to increase the heat-sealing temperature of the cyclic olefin copolymer resin compared to the low-density polyethylene. is there. Therefore, the content of the cyclic olefin copolymer contained in the first cyclic olefin copolymer resin layer 152 is increased to increase the non-adsorption and non-permeability, and the second cyclic olefin copolymer resin layer 153 is increased. The content of the cyclic olefin copolymer contained in the first cyclic olefin copolymer resin layer 152 is made smaller than the content of the cyclic olefin copolymer contained in the first cyclic olefin copolymer resin layer 152, thereby providing non-adsorption and non-permeability. In addition, it is possible to suppress the increase of the heat fusion temperature and to widen the selection range of the temperature for thermocompression bonding. In other words, the effect of the non-adsorbent property of the cyclic olefin copolymer and the property that the heat fusion temperature is higher than that of the low-density polyethylene are controlled by controlling the content of the cyclic olefin copolymer resin, thereby improving the non-adsorbable property. And heat-fusibility.

[Second embodiment]
3 is a schematic sectional view showing a layer configuration of a packaging material 200 according to a second embodiment of the present invention. The packaging material 200 of the second embodiment is a vapor-deposited film in which the barrier layer 140 has a vapor-deposited layer 142 in which an inorganic oxide or a metal is vapor-deposited on one surface of a plastic film 141. It is the same, and the same reference numerals are given and the description is omitted. Note that the vapor deposition layer 142 of the barrier layer 140 is preferably provided on the adhesive resin layer 130 side.

[Third embodiment]
FIG. 4 is a schematic cross-sectional view illustrating a layer configuration of the packaging material 300 according to the third embodiment of the present 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 150, and the same reference numerals are used and the description is omitted. The heat-fusible resin layer 150 of the packaging material 300 includes at least a polyolefin resin layer 151, a first cyclic olefin copolymer resin layer 152, and a second cyclic olefin copolymer resin layer 153 in order from the barrier layer 140 side. The polyolefin resin layer 151 provided on the side of the barrier layer 140 includes at least a polyethylene resin layer 151a and a linear low-density polyethylene resin layer 151b. The polyethylene resin layer 151a is disposed on the side of the barrier layer 140, and the linear low-density polyethylene resin layer 151b is disposed on the side of the first cyclic olefin copolymer resin layer 152.

  As the polyethylene resin layer 151a of the polyolefin resin layer 151, low-density polyethylene, medium-density polyethylene, or high-density polyethylene is used, but low-density polyethylene is preferable. The linear low-density polyethylene resin layer 151b disposed on the side of the first cyclic olefin copolymer resin layer 152 adheres well to the first cyclic olefin copolymer resin layer 152. Further, the low-density polyethylene of the polyethylene resin layer 151a adheres well to the linear low-density polyethylene resin layer 151b. Therefore, by forming the polyolefin resin layer 151 in such a multilayer structure, the interlayer adhesion between each layer and the adjacent layer is improved, and the adhesive strength obtained by heat-sealing the heat-fusible resin layers 150 of the liquid paper container 10 to each other. Can be high.

  Next, a state in which the top heat-sealing portion 12 of the liquid paper container 10 is heat-pressed will be described with reference to FIGS. 5, 6, and 7. FIG.

  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 into a predetermined shape by applying a ruled line to the packaging material, a substantially rectangular blank is folded and one of the opposed ends is, for example, a frame. The body heat-sealed portion 11 is heat-sealed with a seal and adhered to a cylinder, so that a flat state is obtained in which the body is adhered and folded into a tubular shape before assembly is completed. This is supplied to a liquid paper container filling and sealing device, and as shown in FIG. 6, a folded flat liquid paper container is opened and a square tube having an open top end 14 and an open bottom end 15 at both ends. The liquid paper container 10 ′ before assembly is completed, first folded and heated and pressed by a crease on the bottom side to form a bottom portion. After filling the contents from the opening top end portion 14, the top forming plate is bent and bent. To form a gable-top mold (gable mold), and then heat the inner surface. Finally, the top heat-sealed portion 12 of the top-forming plate is polymerized and pressure-bonded to form the top, thereby forming the top of the liquid paper container 10. Assembly is completed. Before the contents are filled, the spout 13 is attached to a hole 16 which is cut out in a circular shape slightly larger than the outer diameter of the spout 13 at a predetermined position of the blank, for example.

  FIG. 5 is a perspective view showing a state in which the liquid paper container is formed into a cylindrical shape from the folded state and the folded state before the assembly of the liquid paper container is completed. The opened and cylindrical liquid paper container 10 'before assembly is open at both ends, and has an open top end 14 on one side and an open bottom end 15 on the other. First, the bottom end 15 of the opening is folded with a crease, heated and pressed to form a bottom, and the contents are filled from the top end 14 of the opening. Thereafter, as shown in FIG. 6, the top forming plate is folded in a creasing manner. In FIG. 6, the spout 13 is omitted for simplicity.

  Next, a state in which the inner surface and the outer surface of the top heat-sealed portion 12 of the curled open top end portion 14 'are simultaneously heated will be described with reference to FIG. As shown in FIG. 7, the heating device main body (not shown) includes a chamber section 20 provided with an outer surface heating section 21 and an inner surface heating section 22. The heating is performed by lowering and heating so as to cover, and after heating, is separated from the opening top end portion 14 'which is raised and curled. Upon heating, the lowered chamber portion 20 covers the curled open top end 14 ′ of the liquid paper container, and the inner and outer surfaces of the curled open top end 14 ′ are the inner surface heating unit 22 and the outer surface heating unit 21. As a result, the air heated to a predetermined temperature supplied from the hot air supply unit in the apparatus main body is drawn from a number of hot air injection holes (not shown) of the outer surface heating unit 21 and the inner surface heating unit 22. As shown by a bold arrow in FIG. 7, the inner surface of the top heat-sealed portion 12 is configured to blow hot air toward the top heat-sealed portion 12 to be bonded of the curled open top end 14 ′. Of the heat-fusible resin layer 160 and the thermoplastic resin layer 110 on the outer surface are simultaneously heated and melted. After the heating, the apparatus main body provided with the chamber section 20 rises and separates from the curled open top end 14 '. Next, the top heat-sealing portion 12 is formed by pressure bonding with a top pressing device (not shown), whereby the gable-top type liquid paper container 10 shown in FIG. 1 is completed. High-temperature hot air of usually 300 ° C. or higher is blown to the portion including the top heat-sealed portion 12 in order to press-bond the top heat-sealed portion 12. At this time, as the hot air temperature becomes higher, bubbling is more likely to occur. Therefore, it is preferable that the optimal range of the hot air temperature (seal temperature) is wide in order to obtain a stable seal state.

Note that the present invention is not limited to the above-described embodiment, and typical configuration examples are listed below.
(1) Thermoplastic resin layer 110 / paper base layer 120 / adhesive resin layer 130 / barrier layer 140 / heat-fusible resin layer 150 [polyolefin resin layer 151 / first cyclic olefin copolymer resin layer 152 / first No. 2 cyclic olefin copolymer resin layer 153]
(2) thermoplastic resin layer 110 / paper base layer 120 / adhesive resin layer 130 / barrier layer 140 / adhesive layer / heat-fusible resin layer 150 [polyolefin resin layer 151 / first cyclic olefin copolymer resin layer 152 / second cyclic olefin copolymer resin layer 153]
(3) Thermoplastic resin layer 110 / paper base layer 120 / adhesive resin layer 130 / barrier layer 140 / heat-fusible resin layer 150 [polyethylene resin layer 151a / linear low-density polyethylene resin layer 151b / first Cyclic olefin copolymer resin layer 152 / second cyclic olefin copolymer resin layer 153]
(4) Thermoplastic resin layer 110 / paper base layer 120 / adhesive resin layer 130 / barrier layer 140 / adhesive layer / heat-fusible resin layer 150 [polyethylene resin layer 151a / linear low-density polyethylene resin layer 151b / First cyclic olefin copolymer resin layer 152 / second cyclic olefin copolymer resin layer 153]

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

[Example 1]
First, a 17.5 μm-thick polyethylene resin layer 151a, a 10 μm-thick linear low-density polyethylene resin layer 151b, a 5 μm-thick first cyclic olefin copolymer resin layer 152, and a 7.5 μm-thick first A cyclic extruded film is formed by forming a heat-fusible resin layer 150 containing a resin made of a cyclic olefin copolymer having a total thickness of 40 μm, in which two cyclic olefin copolymer resin layers 153 are sequentially laminated, by a multilayer inflation method. did. The following resin or resin composition was used for each layer.
Polyethylene resin layer 151a: low-density polyethylene (MFR 4.0 g / 10 min, density 0.923 g / cm ³ )
Linear low-density polyethylene resin layer 151b: linear low-density polyethylene (MFR 2.3 g / 10 min, density 0.914 g / cm ³ )
First cyclic olefin copolymer resin layer 152: cyclic olefin copolymer COC (TOPAS, manufactured by Polyplastics Co., Ltd.)
Second cyclic olefin copolymer resin layer 153: cyclic olefin copolymer COC (TOPAS, manufactured by Polyplastics Co., Ltd.) 40% by mass, linear low-density polyethylene (MFR 2.0 g / 10 min, 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 an antiblocking agent master batch (EMB-21 manufactured by Sumitomo Chemical Co., Ltd.) To prepare a resin composition.

Next, a paperboard having a basis weight of 380 g / m ² is used as the paper base material layer 120, and a biaxially stretched polyethylene terephthalate film (PET) having a thickness of 12 μm is used as the barrier layer 140. An aluminum coating PET film (VMPET) is used to apply an anchor coating agent (AC) to one side of the paperboard, and an ethylene-methacrylic acid copolymer (EMAA) is used as a resin for the adhesive resin layer 130, and the AC side of the paperboard is used. And a VMP (vapor deposition layer) of VMPET were laminated by sandwich lamination while extruding EMAA to a thickness of 25 μm. Next, a two-component curable urethane-based adhesive is applied as an anchor coat agent (AC) to the PET surface of VMPET, and low-density polyethylene (LDPE) is used as a resin for the adhesive layer. The polyethylene resin layer 151a surface of the co-extruded film produced as the resin layer 150 was laminated by sandwich lamination while extruding LDPE to a thickness of 20 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 to be laminated at a thickness of 25 μm by an extrusion coating method. A packaging material was prepared by performing a corona discharge treatment and printing the surface subjected to the corona discharge treatment by a gravure printing method or an offset printing method to provide a printing layer. The composition of the obtained packaging material was a packaging material for a liquid paper container comprising <printed layer / LDPE 25 μm / paperboard 380 g / m ² / EMAA 25 μm / VMPET 12 μm / LDPE 20 μm / heat-fusible resin layer 40 μm>.

[Example 2]
The thickness of each layer of the heat-fusible resin layer 150 used in Example 1 was changed, and a polyethylene resin layer 151a having a thickness of 10 μm, a linear low-density polyethylene resin layer 151b having a thickness of 10 μm, and a fifth layer having a thickness of 5 μm were used. A packaging material was prepared in the same manner as in Example 1, except that the first cyclic olefin copolymer resin layer 152 and the second cyclic olefin copolymer resin layer 153 having a thickness of 15 μm were sequentially laminated. The total thickness was 40 μm as in the example.

[Comparative Example 1]
The thickness of each layer of the heat-fusible resin layer 150 used in Example 1 was changed, and a 5 μm thick polyethylene resin layer 151 a, a 5 μm thick linear low-density polyethylene resin layer 151 b, and a 5 μm thick A packaging material was produced in the same manner as in Example 1, except that the first cyclic olefin copolymer resin layer 152 and the second cyclic olefin copolymer resin layer 153 having a thickness of 25 μm were sequentially laminated. The total thickness was 40 μm as in the example.

[Comparative Example 2]
The thickness of each layer of the heat-fusible resin layer 150 used in Example 1 was changed, and a polyethylene resin layer 151a having a thickness of 16 μm, a linear low-density polyethylene resin layer 151b having a thickness of 16 μm, and a fifth layer having a thickness of 5 μm were used. A packaging material was produced in the same manner as in Example 1, except that the first cyclic olefin copolymer resin layer 152 and the 3 μm-thick second cyclic olefin copolymer resin layer 153 were sequentially laminated. The total thickness was 40 μm as in the example.

  The packaging materials for liquid paper containers obtained in Examples 1 and 2 and Comparative Examples 1 and 2 were evaluated for the non-adsorption property of the packaging material and the suitability for a filling machine, and the results are shown in Table 1.

The evaluation method and evaluation criteria are as follows.
(Non-adsorbent)
A blank was punched out of the packaging material using a punching machine equipped with a die having predetermined ruled lines and a predetermined cutting edge for blank formation. Next, while bending the blank, one of the opposing edges was overlapped as the body heat-sealing portion 11 to perform frame sealing, and was pasted by a box making machine to obtain a cylindrical folded liquid paper container. The folded liquid paper container is opened and assembled by a paper container filling and sealing device equipped with a cylindrical carton assembling device and the like, and the gable-top liquid paper container 10 shown in FIG. Was filled with Ginjo Sake and hermetically sealed. On the other hand, the same bottle of Ginjo was filled in a glass bottle and sealed. Then, after each was stored at room temperature (25 ° C.) for 10 days, isoamyl acetate contained in the glass bottle and the Ginjo sake in the gable-top type liquid paper container 10 was quantitatively analyzed by gas chromatography, and the Ginjo wine in the glass bottle was analyzed. The ratio of isoamyl acetate contained in Ginjo sake in the gable-top type liquid paper container 10 to the contained amyl acetate was determined as the residual ratio, and the non-adsorption property was evaluated based on the residual ratio of isoamyl acetate. The fragrance is an important factor in determining the quality of Ginjo liquor, and isoamyl acetate, a fragrant ester, is considered to be one of the most preferable fragrance components similar to the fragrance of fruit. Attention was focused on isoamyl acetate, which forms one component, and the residual rate was evaluated.

[Filling machine suitability]
The temperature of the chamber (see FIG. 8) of the paper container filling and sealing apparatus was changed from 240 ° C. to 360 ° C. every 10 ° C., and the contents were filled and sealed. The gable-top type liquid paper container 10 sealed and packaged was visually inspected for leakage of contents and the presence or absence of pinholes, and the temperature at which no abnormality was found was regarded as an appropriate temperature. The presence or absence of a pinhole is as follows.
(Method of Confirming Pinholes) A test sample was obtained by cutting the liquid paper container 10 shown in FIG. 1 horizontally between the top portion 17 and the bottom portion 18 and bisecting the liquid vertically to remove the contents. The test liquid was poured from the cut end of the test sample with the cut end of the top part 17 and the bottom part 18 facing upward, and the sample was allowed to stand for about one hour with the cut end facing upward. Thereafter, a destructive inspection was performed to determine whether the test liquid had penetrated the heat-sealed portions of the top portion 17 and the bottom portion 18. Those in which coloring was recognized in the paper base material layer 120 were determined to be defective, and those in which no coloring was recognized were determined to be good. In addition, as a test solution, a microcheck permeate (Ichinen Chemicals) was used.

  As shown in Table 1, in Examples 1 and 2, the residual ratio of isoamyl acetate was good, and excellent non-adsorption property was recognized. Also, the suitability range of the sealing temperature was wide and the suitability of the filling machine was good. In Comparative Example 1, the suitability for the filling machine was good, but the decrease in isoamyl acetate was remarkable, and the non-adsorption property was poor. In Comparative Example 2, although the non-adsorption property was good, the suitable range of the sealing temperature in the filling machine suitability was narrow, and stable actual work was difficult.

Reference Signs List 10 Liquid paper container 10 'Liquid paper container before completion of assembly 11 Body heat fusion part 12 Top heat fusion part 13 Outlet part 14 Open top end 14' Curved folded 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 Plastic film 142 Deposition layer 150 Thermal fusion Resin layer 150s Surface 150h of heat-fusible resin layer 150h Position at 1/2 of total thickness of heat-fusible resin layer 151 Polyolefin resin layer 151a Polyethylene resin layer 151b Linear low-density polyethylene resin layer 152 First Cyclic olefin copolymer resin layer 153 of second cyclic olefin copolymer resin layer

Claims (4)

A packaging material having at least a thermoplastic resin layer, a paper base material layer, an adhesive resin layer, a barrier layer, and a heat-fusible resin layer containing a resin made of a cyclic olefin copolymer,
The heat-fusible resin layer includes at least a polyolefin resin layer, a first cyclic olefin copolymer resin layer, and a second cyclic olefin copolymer resin layer in order from the side of the barrier layer,
The first cyclic olefin copolymer resin layer contains at least 80% by mass of a resin made of the cyclic olefin copolymer,
The second cyclic olefin copolymer resin layer contains a resin composed of the cyclic olefin copolymer in an amount of 10% by mass or more and 80% by mass or less,
The first cyclic olefin copolymer resin layer is １ ／ of the total thickness of the heat-fusible resin layer from the exposed surface of the heat-fusible resin layer in the thickness direction of the heat-fusible resin layer. A packaging material, wherein the packaging material is located between 5 μm and 20 μm from the exposed surface of the heat-fusible resin layer. The packaging material according to claim 1, wherein the thickness of the adhesive resin layer is 15 μm or more and 50 μm or less. The packaging material according to claim 1, 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 plastic film. The polyolefin resin layer provided on the side of the barrier layer of the heat-fusible resin layer includes at least a polyethylene resin layer and a linear low-density polyethylene resin layer. Crab packaging material.

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