JP6171557B2 - Liquid paper container - Google Patents

Description

  The present invention relates to a liquid paper container, and more particularly to a liquid paper container that can be easily opened during use or disassembled after use.

  Conventionally, as a liquid paper container, from a paper container with a simple structure in which a thermoplastic resin layer is provided on the front and back surfaces of a paper like a milk pack, a gas barrier layer is provided on the inner surface to further sterilize the inside and store at room temperature for a long time. Various liquid paper containers have been put into practical use, including paper containers with stoppers that ensure their properties.

  In general, a liquid paper container is formed by bending a laminated body mainly composed of paper along a ruled line and heat-sealing, so that the outermost surface and the innermost surface of the laminated body can be heat-sealed. A thermoplastic resin layer is required. As these thermoplastic resins, polyethylene resin (PE) is most commonly used, and among them, low density polyethylene resin (LDPE) and linear low density polyethylene resin (LLDPE) are widely used.

  However, when polyethylene resin is used for the sealant layer on the innermost surface, since the polyethylene resin has good heat sealing properties, the seal part is firmly bonded, often causing difficulty in opening operation and dismantling after use. It was sometimes accompanied. Especially for large paper containers with caps with a capacity of 2 liters, the thickness of the laminate constituting the container is also thick, and it is not assumed that the upper part of the container is opened and opened like a milk pack. When dismantling after use, there is a problem that it cannot be easily disassembled by a weak hand.

Thus, several methods have been proposed for facilitating the opening and disassembly of paper containers.
In Patent Documents 1 to 3, a release agent is applied to a specific part of the sealant layer of the top seal part to weaken the seal strength of the top seal part in order to facilitate opening and dismantling of the gable top type paper container. A method for facilitating openability and disassembly is described.

  However, the method of relying only on the release agent for easy opening and easy disassembly has the following problems. That is, according to this method, a part having a very weak adhesion in which a release agent is present and a part having a very strong adhesion without a release agent are mixed together. It is a problem that it is practically difficult to achieve both the sealing performance and stability. Although it is very effective to use the release agent in a small area so as to trigger opening (or dismantling), it is not appropriate to adopt this method over the entire seal site.

  This is because the release agent is generally transparent, but in order to partially form the release agent on the surface of the sealant layer, which is the back side of the laminate, a double-sided printing machine is used to print a pattern on the front side. There is only a way to print using. However, it is not easy to print a transparent release agent on the back side of the sheet while aligning it with the front side. If misalignment occurs, it will lead to a seal failure and serious defects such as liquid leakage. There is a fear of developing.

The liquid paper container filed by the applicant described in Patent Document 4 has been made in order to solve the above-described problem. Similarly, in the gable top type liquid paper container, a part is not provided on the surface side of the top seal portion. A peeling varnish coating film is provided, and an easy peel tape is stuck on the back side. This liquid paper container is an extremely easy-to-use paper container because the peeling varnish coating effectively works as a trigger for opening, and the easy peel tape provides smooth and stable easy peeling. Moreover, since the peeling varnish coating film is on the surface side, it can be formed without any problem in the printing process, and a product with stable quality can be supplied.

  However, since the liquid paper container described in Patent Document 4 needs to stick an expensive easy peel tape to a specific position of the blanks, it has to be expensive as a result of an increase in material costs and process costs. There was a problem in terms of practicality.

  As methods for pursuing easy opening while preventing an increase in cost, there are methods disclosed in Patent Documents 5 and 6.

  The packaging container described in Patent Document 5 and the method for manufacturing the packaging container provide a portion where the thickness of the resin is small by locally heating the resin at a specific fusion site and then scraping off the resin, thereby partially increasing the sealing strength. By making it weak, it is easy to open.

  Moreover, the packaging container described in patent document 6 and its manufacturing method implement | achieve easy-opening property by lowering | hanging the fusion | melting temperature of a specific fusion | melting site | part, and weakening seal strength partially. .

  According to the methods described in Patent Documents 5 and 6, there is no major cost increase factor, and easy-openability should be realized. However, since delicate temperature control is required in the box making process, It is difficult to manage the unsealing property at a certain level, and it is practically extremely difficult to achieve both stable unsealing property and sealing property.

Japanese Utility Model Publication No. 5-58621 Japanese Utility Model Publication No.9-191 JP 2008-87771 A Japanese Patent No. 3255075 JP 2007-168851 A JP 2007-168872 A JP 2012-86857 JP

  The laminate for paper containers and the liquid paper container using the same, which are the applications of the applicant described in Patent Document 7, are intended to solve the above problems, and the quality of the blank manufacturing process and the box making process is improved. The present invention proposes a laminate for paper containers that is easy to manage, exhibits stable easy-openability or easy-disassembly, and does not bring about a large cost increase, and a liquid paper container using the same.

  The liquid paper container described in Patent Document 7 uses a sealant layer in which a low crystalline rubber component is blended with a polyolefin-based resin, thereby realizing easy opening and easy disassembly. In terms of ease of dismantling, it was still not fully satisfactory.

  The problem to be solved by the present invention is to propose a liquid paper container that is easy to control the quality in the blank manufacturing process and the box making process and that stably exhibits sufficient easy opening and dismantling properties. .

  As means for solving the above problems, the invention according to claim 1 is based on paper, has a thermoplastic resin layer (surface resin layer) on the surface, and at least a gas barrier layer and a sealant layer on the back surface. A liquid paper container formed by molding a laminate having a surface on the outside of the container, wherein the sealant layer has two or more easy peel layers obtained by blending an elastomer component with a polyethylene resin, Two of them are liquid paper containers that are arranged adjacent to each other to form a liquid contact surface.

  The liquid paper container according to the present invention has two easy peel layers arranged on the innermost sealant layer that constitutes the liquid contact surface, so that easy peelability is stably exhibited and sufficient easy opening and dismantling. It has become possible to realize the stability stably.

  The invention according to claim 2 is the liquid paper container according to claim 1, wherein the liquid paper container is a gable top type paper container having a gable roof top.

  The invention according to claim 3 is the liquid paper container according to claim 1 or 2, wherein the gas barrier layer is a polyethylene terephthalate film on which a metal or a metal oxide is deposited.

  The invention according to claim 4 is the liquid paper container according to any one of claims 1 to 3, wherein the sealant layer has a polyethylene resin layer.

  The invention according to claim 5 is characterized in that the liquid paper container has a stopper thermally welded to the liquid contact surface of the sealant layer of the laminate. The liquid paper container according to the item.

  The invention according to claim 6 is the liquid paper container according to claim 5, wherein the plug has an easy peel layer on a heat welding surface with the sealant layer.

  A liquid paper container according to the present invention is a liquid paper obtained by molding a paper-based laminate having a thermoplastic resin layer (surface resin layer) on the front surface and at least a gas barrier layer and a sealant layer on the back surface. Because it is a container, its main raw material is reproducible paper, and there is little impact on the global environment. In addition, since it is handled as a paper container for disposal or recycling after use, it has a significant legal advantage compared to plastic containers.

  In addition, since the liquid paper container according to the present invention has a gas barrier layer, the contents can be stored with high stability and can be used as a container for storing various liquids.

  The liquid paper container according to the present invention has two or more easy peel layers obtained by blending an elastomer component with polyethylene resin as a sealant layer, and two of these layers are arranged adjacent to each other to form a liquid contact surface. As a result, when opening or disassembling, the seal portion stably coheses and breaks, so that it can be easily opened or disassembled by a human hand.

  The liquid paper container according to the present invention can be applied without any trouble even when it is a gable top type paper container having a gable roof type top, which is most commonly used, as in the invention described in claim 2. Therefore, it can be widely deployed in various applications.

In addition, when the gas barrier layer is a polyethylene terephthalate film on which a metal or metal oxide is vapor-deposited as in the invention described in claim 3, it is not necessary to use an aluminum foil, so that it can be stored at room temperature for a long time. Although it is present, a liquid paper container excellent in recyclability can be obtained.

  When the sealant layer includes a polyethylene resin layer as in the invention described in claim 4, the polyethylene resin layer and the easy peel layer are simultaneously and efficiently formed using a method such as a co-extrusion method. It becomes possible to do.

  Further, as in the invention according to claim 5, when the liquid paper container has a spout thermally welded to the liquid contact surface of the sealant layer of the laminate, the easy peel having two layers of the liquid contact surface Since it is composed of layers, it is possible to easily remove the plug by hand when dismantling after use.

  Furthermore, as in the invention according to claim 6, when the plug itself has an easy peel layer on the heat-welded surface with the sealant layer, removal of the plug at the time of disassembly is further facilitated. Become.

FIG. 1 is a perspective view showing an embodiment of a liquid paper container according to the present invention. FIG. 2 is an explanatory plan view showing a state where the blank of the liquid paper container shown in FIG. 1 is viewed from the front side. FIG. 3 is a schematic cross-sectional view showing an embodiment of a laminate used in the liquid paper container according to the present invention. FIG. 4 is a schematic cross-sectional view showing another embodiment of the laminate used in the liquid paper container according to the present invention. FIG. 5 is a perspective view showing another embodiment of the liquid paper container according to the present invention. FIG. 6 is an explanatory plan view showing a state in which the blank of the liquid paper container shown in FIG. 5 is viewed from the front side. FIGS. 7A and 7B are perspective views showing other embodiments of the liquid paper container according to the present invention. FIG. 8 is a cross-sectional explanatory view of the plug portion in one embodiment of the liquid paper container according to the present invention. FIG. 9 is a cross-sectional explanatory view of a plug portion in another embodiment of the liquid paper container according to the present invention.

Hereinafter, the liquid paper container (1) according to the present invention will be described in detail with reference to the drawings.
FIG. 1 is a perspective view showing an embodiment of a liquid paper container (1) according to the present invention. FIG. 2 is an explanatory plan view showing a state in which the blank (10) of the liquid paper container (1) shown in FIG. 1 is viewed from the surface side of the laminate (20). FIG. 3 is a schematic cross-sectional view showing one embodiment of the laminate (20) used in the liquid paper container (1) according to the present invention. FIG. 4 is a schematic cross-sectional view showing another embodiment of the laminate (20) used in the liquid paper container (1) according to the present invention.

  The liquid paper container (1) according to the present invention is based on paper (23), has a thermoplastic resin layer (hereinafter referred to as a surface resin layer (22)) on the surface, and at least a gas barrier layer (25) on the back surface. And a liquid paper container formed by molding a laminate (20) having a sealant layer (27) so that the surface is outside the container.

  The embodiment shown in FIG. 1 is an example of a gable top paper container having a gable roof top. The shape of the paper container is not limited to the gable top type, and may be a brick type as shown in FIGS. 7A and 7B or other shapes. Moreover, as shown to FIG. 5, FIG. 7 (2), the structure which has a stopper (3) may be sufficient.

  In the liquid paper container (1) according to the present invention, the sealant layer (27) has two or more easy peel layers obtained by blending an elastomer component with polyethylene resin, and two of them (28a, 28b) It is characterized by being arranged adjacent to each other to form a liquid contact surface.

  In the example shown in FIG. 3, a surface resin layer (22) and an ink layer (21) made of a thermoplastic resin are provided on the surface side of the base paper (23), and on the back side of the paper, A gas barrier layer (25) is laminated via an adhesive resin layer (24), and a sealant layer (27) comprising a polyethylene resin layer (29), an easy peel layer (28a), and an easy peel layer (28b) is further provided. And are laminated via an adhesive layer (26).

  In this example, two easy peel layers (28a, 28b) are arranged adjacent to each other to constitute the innermost surface which is a liquid contact surface.

  In the example shown in FIG. 4, the process from the surface side to the adhesive layer (26) is the same as in FIG. 3, but the sealant layer (27) is composed of the polyethylene resin layer (29a) and the easy peel layer in order from the top. (28c), a polyethylene resin layer (29b), an easy peel layer (28a), and an easy peel layer (28b). In this example, there are three easy peel layers, but two of them (28a, 28b) are arranged adjacent to each other to form a liquid contact surface.

  As described above, in the liquid paper container (1) according to the present invention, the sealant layer (27) composed of a plurality of layers is used, and two easy peel layers (28) are adjacent to the liquid contact surface which is the innermost layer. Therefore, the heat-sealed surface after molding is easily peeled off, and easy-openability and easy-disassembly are stably exhibited. This is considered to be caused by the fact that two easy peel layers are provided, so that cohesive peeling or delamination becomes easy between the layers or within the layers.

  For the easy peel layer, an elastomer component is blended with polyethylene resin such as high density polyethylene resin (HDPE), medium density polyethylene resin (MDPE), low density polyethylene resin (LDPE), and linear low density polyethylene resin (LLDPE). A resin layer is used. The polyethylene resin may be a single type or a combination of several types. For example, LDPE and LLDPE may be combined, or different types of LLDPE may be used.

  Among the polyethylene resins, LLDPE is particularly preferable in terms of sealing properties, and LLDPE having a density of 0.925 or less and a melt flow rate (MFR) of 2 or more is effective.

The elastomer component blended with these polyethylene resins includes ethylene / α-olefin copolymer, polybutene-1 (PB), styrene / isoprene copolymer, styrene / isobutylene copolymer and its hydrogenated product, polystyrene (PS ), Cyclic olefin copolymer (COC), cyclic olefin polymer (COP), and the like.

  The blending amount of the elastomer component in each easy peel layer is suitably 5 to 50%, and the type and blending amount of the elastomer component may differ depending on the layer. Further, the thickness of the easy peel layer is suitably 5 to 50 μm for each layer, and the total range of 30 to 100 μm is appropriate, and a total of about 60 μm is appropriate.

As the adhesive layer (26) for bonding the gas barrier layer (25) and the sealant layer (27), a known dry laminate adhesive or non-solvent laminate adhesive can be used. The coating amount at this time is 0.5 to 5.0 g / m ² (dry). Instead of the adhesive layer (26), bonding may be performed by an extrusion laminating method using an adhesive resin.

Next, an example of a procedure for actually manufacturing the laminate (20) shown in FIG. 3 will be described.
For example, dry laminate is a sealant film in which three layers of LLDPE / LLDPE + PB (30%) / LLDPE + PB (40%) are coextruded as a sealant layer (27) on the PET surface side of an aluminum-deposited PET film as a gas barrier layer (25) Is laminated by dry laminating method using adhesive for adhesive, and then the vapor-deposited side of aluminum vapor-deposited PET film and paper substrate (23) are bonded together by extrusion laminating method using polyethylene resin as adhesive resin layer (24) A low density polyethylene resin (LDPE) is extruded and laminated as a surface resin layer (22) on the surface side opposite to the paper. In this case, the aluminum vapor-deposited PET film may be turned upside down.

  By printing the ink layer (21) on the surface of the laminate thus obtained by a known printing method such as a gravure printing method, an offset printing method, a screen printing method, or a flexographic printing method, it is shown in FIG. A laminated body (20) having a layer structure as described above is obtained.

  In the process of producing the laminate (20), the bonded surface may be subjected to a surface activation treatment such as ozone treatment or corona treatment, or an anchor coating agent may be applied. In particular, it is desirable to perform corona treatment on the printing surface in advance.

As the paper (23) as the base material, a paper having a basis weight of 200 to 500 g / m ² and a density of 0.6 to 1.1 g / cm ³ is selected and used according to the size of the paper container. It is preferable. When the basis weight is less than 200 g / m ² , there is a possibility that sufficient waist and strength as a container cannot be obtained. Moreover, when it exceeds 500 g / m < ² >, the processability at the time of shape | molding to a container is inferior, and it is not preferable economically.

  Common materials used for the surface resin layer (22) include low density polyethylene resin (LDPE), medium density polyethylene resin (MDPE), high density polyethylene resin (HDPE), and linear low density polyethylene resin (LLDPE). Olefin resins such as ethylene-α olefin copolymers, homopolypropylene resins, propylene-ethylene random copolymers, propylene-ethylene block copolymers, propylene-α olefin copolymers, and graft polymerization of these olefin resins. A modified polyolefin resin that has been acid-modified by, for example, can be used. The thickness is suitably in the range of 10 to 30 μm.

  As the gas barrier layer (25), a gas barrier resin film, a gas barrier laminated film in which a gas barrier layer is formed on a base film, or a metal foil such as an aluminum foil can be used.

As the gas barrier resin film, an ethylene-vinyl alcohol copolymer film (
EVOH), polyvinyl alcohol film (PVA), biaxially stretched PET, biaxially stretched nylon film and EVOH laminated film, saponified ethylene-vinyl acetate copolymer (EVA), polyvinylidene chloride film, and the like.

  As the gas barrier laminated film, a laminated film combining two or more of the above gas barrier films, an inorganic oxide vapor deposited film obtained by depositing an inorganic oxide such as aluminum oxide or silicon oxide on a base film, an aluminum vapor deposited film, Alternatively, there are a coated film obtained by coating polyvinylidene chloride on a base film, and an aluminum foil laminated film obtained by laminating an aluminum foil.

  As a base film of the gas barrier laminate film, polyester films such as polyethylene terephthalate (PET), polyethylene naphthalate (PEN), polybutylene terephthalate (PBT), polypropylene film (PP), nylon-6, nylon-66, etc. Non-stretched or stretched films such as polyamide film, polycarbonate (PC), polystyrene (PS), polyacrylonitrile (PAN), and polyimide (PI) are used.

  Among these, the vapor deposition PET film which vapor-deposited alumina, silica, or aluminum in the thickness of 5-100 nm on the PET film of thickness 6-25 micrometers, and the aluminum of thickness 5-15 micrometers on the PET film of thickness 6-25 micrometers. A laminate film in which a foil is bonded is preferably used.

  As the adhesive resin layer (24) used for bonding the paper (23) and the gas barrier layer (25), in addition to a general polyethylene resin, a so-called no-anchor coat polyethylene such as an epoxidized vegetable oil-containing polyethylene resin. Resins, acid copolymers such as ethylene / acrylic acid copolymer resin (EAA), ethylene / methacrylic acid copolymer resin (EMAA), acid anhydride graft-modified polyethylene resin, ethylene / vinyl acetate copolymer resin (EVA) A single resin such as an ethylene / ethyl acrylate copolymer resin, an ethylene / methacrylic acid / methacrylic acid ester terpolymer resin, or an ionomer resin, or a co-extrusion of these resins and a polyethylene resin can be used. These resins are melted, and the paper (23) and the gas barrier layer (25) are bonded together by an extrusion lamination method. The thickness of the resin layer is suitably in the range of 10 to 50 μm.

  As the sealant layer (27), as described above, two or more easy peel layers (28a, 28b) can be efficiently formed by a coextrusion method based on the polyethylene resin layer (29). In this case, a sealant film formed by a co-extrusion method using a T die or a co-inflation method may be bonded to the gas barrier layer (25) by a dry laminating method, or directly extruded from the T die and laminated. Also good.

  When the easy peel layer (28) is formed by coextrusion with the polyethylene resin (29), the thickness of each easy peel layer is 10 μm or more, and the thickness of the polyethylene resin layer is 20 μm or more. A thickness of 30 to 100 μm is appropriate as a whole. More preferably, it is 40 μm or more, and most preferably about 60 μm.

  As the polyethylene resin used for the innermost easy peel layer to be the wetted surface, a polyethylene resin having a low temperature sealing property is preferable.

FIG. 2 is an explanatory plan view showing a state where the blank of the liquid paper container shown in FIG. 1 is viewed from the front side. To assemble the blank of FIG. 2, four side plates (13) are formed into a square cylinder by folding the ruled line (11) between them and heat-sealing the adhesive margin, and then the bottom and top are formed. Mold. In forming the top part, the roof part is composed of two sets of triangular top plates (15) constituting the gable part of the gable roof and the folded top seal part (18) continuously provided on the upper part of the folded triangular plate (16). It heat-seal | pinches by pinching | interposing between the top seal part (17) provided in a row on the upper part of two rectangular top boards (14).

  FIG. 5 is a perspective view showing another embodiment of the liquid paper container (1) according to the present invention. FIG. 6 is an explanatory plan view showing a state in which the blank (10) of the liquid paper container (1) shown in FIG. 5 is viewed from the front side. The liquid paper container (1) shown in FIGS. 5 and 6 is a gable top type liquid paper container with a cap (3). One rectangular top plate (14) of the two rectangular top plates is provided with a plug attachment hole (12), to which the plug (3) is attached.

  7 (1) and (2) are perspective views showing other embodiments of the liquid paper container (1) according to the present invention. FIG. 7 (1) is a liquid paper container called a brick type or a flat top type, and FIG. 7 (2) is a liquid paper container with a stopper with a stopper (3) attached thereto. In these forms of paper containers as well, liquid paper containers having easy opening and dismantling properties can be obtained.

  8 and 9 are cross-sectional explanatory views of the plug (3) portion of the liquid paper container according to the present invention. The plug (3) attached to the liquid paper container according to the present invention comprises a liquid contact surface of the sealant layer (27) of the laminate (20) and a heat sealing seal part (4) of the plug (3). It is attached by heat welding.

  The material of the plug (3) is usually a polyethylene resin alone, but in the liquid paper container (1) according to the present invention, the easy peel layer (28a, 28a, 28b), it is easy to remove the plug at the time of dismantling. When the material of the plug (3) is made of the same resin composition as that of the easy peel layer, the plug can be easily removed at the time of dismantling.

  As shown in FIG. 9, when the plug (3) has the easy peel layer (5) only on the heat-welded surface with the sealant layer (27), the plug can be easily removed during disassembly. Can be. When such a plug (3) is used, it becomes possible to easily remove the plug (3) by hand from the laminate (20) during disassembly after use. Hereinafter, the liquid paper container (1) according to the present invention will be described more specifically based on examples.

In accordance with the layer structure shown in FIG. 3, a carton base paper having a basis weight of 380 g / m ² was used as the paper (23), and an alumina vapor deposition film in which an alumina vapor deposition layer was formed on a PET film having a thickness of 12 μm as the gas barrier layer (25). used.

  A coextruded sealant film consisting of three layers was used as the sealant layer (27). The first layer is an LLDPE with a density of 0.911 and a melt flow rate (MFR) of 14 μm, and the second layer is an easy peel having a thickness of 20 μm made of a resin composition obtained by blending 30% of polybutene-1 as an elastomer component with the same LLDPE. Layer (abbreviated as PB30 in the table), and the third layer is an easy peel layer (thickness 20 μm) in which 40% polybutene-1 as an elastomer component is blended with LLDPE having a density of 0.904 and a melt flow rate of 8. , Abbreviated as PB40, and so on). The third layer is the wetted surface.

First, the alumina vapor-deposited film and the sealant layer (27) were bonded together by a dry laminating method using an adhesive (26). Next, as the adhesive resin layer (24) for bonding the alumina vapor-deposited film and paper (23), LDPE having a thickness of 30 μm was extruded and laminated. Further, LDPE having a thickness of 18 μm was extrusion laminated on the surface of the carton base paper, and the surface was subjected to corona treatment, and then an ink layer (21) was formed by a printing machine. Using the laminate (20) thus obtained, a gable top type liquid paper container with a stopper as shown in FIG. 5 was produced. The paper container is 85 mm square and has a capacity of 2 liters.

  In Example 1, the same procedure as in Example 1 was carried out except that the polybutene-1 of the second easy peel layer of the sealant layer was 40% and the polybutene-1 of the third easy peel layer was 30%. Two liquid paper containers were prepared.

  In Example 1, the liquid paper container of Example 3 was prepared in the same manner as in Example 1 except that the second layer of the sealant layer was an easy peel layer to which 30% cyclic olefin copolymer (COC) was added as an elastomer component. Produced.

  In Example 1, a liquid paper container of Example 4 was produced in the same manner as in Example 1 except that the second layer of the sealant layer was an easy peel layer to which 30% of polystyrene (PS) was added as an elastomer component. .

  In Example 1, the liquid paper container of Example 5 was produced in the same manner as Example 1 except that the thickness of the first layer of the sealant layer was 30 μm and the thickness of the third layer was 10 μm.

  Example 1 Example 1 was performed in the same manner as Example 1 except that the thickness of the first layer of the sealant layer was 10 μm, the thickness of the second layer was 10 μm, and the thickness of the third layer was 40 μm. 6 liquid paper containers were produced.

  In Example 1, a liquid paper container of Example 7 was produced in the same manner as in Example 1 except that 30% of polybutene-1 was added to the first layer of the sealant layer.

  In Example 1, the liquid paper container of Example 8 was prepared in the same manner as in Example 1 except that the LLDPE of the second and third layers of the sealant layer was LLDPE having a density of 0.904 and a melt flow rate of 4. Produced.

  In Example 8, a liquid paper container of Example 9 was produced in the same manner as in Example 8, except that the addition amount of polybutene 1 in the third layer of the sealant layer was 30%.

  In Example 8, the liquid paper container of Example 10 was the same as Example 8 except that the first LLDPE of the sealant layer was LLDPE of the same grade as that used for the second and third layers. Was made.

A liquid paper container of Example 11 was produced in the same manner as in Example 1 except that the sealant layer in Example 1 was a five-layer sealant layer having the following configuration.
First layer: The same specifications as those of the first layer in Example 1, and the thickness was 10 μm.
Second layer: The same specifications as those of the second layer in Example 1, and the thickness was 10 μm.
Third layer: Same specifications as the first layer in Example 1, with a thickness of 10 μm.
Fourth layer: The same specifications as the third layer of Example 1 were used, and the thickness was 10 μm.
5th layer: Same specifications as the 2nd layer in Example 1.

<Comparative Example 1>
In Example 1, the specification of the sealant layer is the same as that of Example 1 except that the thickness of the first layer is 60 μm, the second layer, the third layer are not provided, and the single sealant layer is used. One liquid paper container was produced. Comparative Example 1 is a standard specification of a conventional liquid paper container.

<Comparative example 2>
In Example 1, a liquid paper container of Comparative Example 2 was prepared in the same manner as in Example 1 except that polybutene 1 was not added to the third layer.

<Comparative Example 3>
In Example 1, the specifications of the sealant layer are the same as in Example 1 except that the second layer of polyethylene resin is LDPE having a density of 0.92 and a melt flow rate of 8, and polybutene 1 is not added to the third layer. Thus, a liquid paper container of Comparative Example 3 was produced.

<Comparative Example 4>
In Example 1, the specifications of the sealant layer were the same as in Example 1 except that polybutene 1 was not added to the second layer and the LLDPE of the third layer was LLDPE having a density of 0.904 and a melt flow rate of 4. In the same manner as in Example 1, a liquid paper container of Comparative Example 4 was produced.

<Comparative Example 5>
In Example 1, the specifications of the sealant layer were compared in the same manner as in Example 1 except that the third layer of Example 1 was used as the first layer and the first layer of Example 1 was used as the second layer. The liquid paper container of Example 5 was produced.

  Each of the liquid paper containers of Examples and Comparative Examples was filled with water and hermetically sealed. After opening the stopper and discarding the water, the measurement of the opening (disassembly) strength with a tensile tester, observation of the peeled surface, and easy disassembly by hand were evaluated.

  The disassembly strength was measured with a tensile tester by measuring the peel strength [N] when the top seal portion of the paper container was held diagonally with a chuck and pulled at a tensile speed of 300 mm / min. Evaluation of easy disassembly by hand is sensory evaluation. Table 1 shows the specifications and evaluation results of the sealant layer of each sample.

  From the results in Table 1, compared to Comparative Example 1 corresponding to a conventional paper container, Comparative Examples 2 to 4 using only one easy peel layer, and Comparative Example 5 in which two easy peel layers are not adjacent to each other It can be seen that the liquid paper container according to the present invention is excellent in easy disassembly and can be easily disassembled by hand.

  Since the liquid paper container according to the present invention has gas barrier properties, it can be widely used as a container for storing various non-food liquids as well as alcoholic beverages, non-alcoholic beverages, and liquid foods.

DESCRIPTION OF SYMBOLS 1 ... Liquid paper container 2 ... Container main body 3 ... Mouth plug 4 ... Seal part 5 for heat fusion | bonding ... Easy peel layer 10 ... Blank 11 ... Ruled line 12 ... Mouth Plug mounting hole 13 ... side plate 14 ... rectangular top plate 15 ... triangular top plate 16 ... folded triangular plate 17 ... top seal part 18 ... folded top seal part 20 ... laminate 21 ... Ink layer 22 ... Surface resin layer 23 ... Paper 24 ... Adhesive resin layer 25 ... Gas barrier layer 26 ... Adhesive layer 27 ... Sealant layers 28a, 28b, 28c ...・ Easy peel layer 29, 29a, 29b ... polyethylene resin layer

Claims (6)

  A liquid paper container comprising a paper base material, a thermoplastic resin layer on the front surface, and a laminate having at least a gas barrier layer and a sealant layer on the back surface, the front surface being formed outside the container, The sealant layer has two or more easy peel layers obtained by blending an elastomer component with a polyethylene resin, and two of the layers are arranged adjacent to each other to form a liquid contact surface. container.   The liquid paper container according to claim 1, wherein the liquid paper container is a gable top type paper container having a gable roof type top.   The liquid paper container according to claim 1, wherein the gas barrier layer is a polyethylene terephthalate film on which a metal or a metal oxide is deposited.   The liquid paper container according to claim 1, wherein the sealant layer has a polyethylene resin layer.   The liquid paper container according to any one of claims 1 to 4, wherein the liquid paper container has a stopper thermally welded to a liquid contact surface of the sealant layer of the laminate.   The liquid paper container according to claim 5, wherein the plug has an easy peel layer on a heat welding surface with the sealant layer.

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