JP2012086857A - Laminate body for paper container, and paper container for liquid using the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a laminate body for a paper container, which facilitates quality management in a blank manufacturing process and a can making process, exerts a stable easy-opening property or an easy-disassembling property without significant increase in cost, and the paper container for liquid using the same.SOLUTION: The laminate body using paper as a base material includes at least a surface resin layer on the surface side and at least a gas barrier layer and a sealant layer on the reverse side. The surface resin layer and/or the sealant layer is obtained by blending a low-crystalline rubber component with a polyolefin resin.

Description

  The present invention relates to a laminate for paper containers and a liquid paper container using the same, and more particularly to a liquid paper container that can be easily opened and 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 long periods 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

  The problem to be solved by the present invention is that the quality control in the blank manufacturing process and the box making process is easy, the easy-opening property or the easy-to-disassemble property is exhibited, and the lamination for the paper container which does not bring a large cost increase. A body and a liquid paper container using the body are proposed.

As a means for solving the above-mentioned problems, the invention according to claim 1 is a paper-based laminate having at least a surface resin layer on the front surface and at least a gas barrier layer and a sealant layer on the back surface. The surface resin layer and / or sealant layer is a laminate for paper containers, wherein the polyolefin resin is blended with a low crystalline rubber component.

  In the invention according to claim 2, the polyolefin resin is a polyethylene resin, and the low crystalline rubber component is selected from polybutene-1, poly (ethylene-butene), and poly (propylene-butene). It is 1 or more types, It is a laminated body for paper containers of Claim 1 characterized by the above-mentioned.

  The invention according to claim 3 is a liquid paper container formed by molding the laminate for paper containers according to claim 1 or 2 so that the surface of the laminate is outside the container.

  Further, the invention according to claim 4 has a gable roof mold top formed by molding the laminate for paper containers according to claim 1 or 2 so that the surface of the laminate is outside the container. Gable-top type liquid paper container with two rectangular tops that constitute the roof part, with two sets of triangular top plates that form the gables of the gable roof and a folding top seal that is connected to the top of the folding triangular plate It is heat-sealed by sandwiching it with a top seal portion continuously provided on the upper part of the plate, and on the surface resin layer on the surface side of the folded top seal portion, a peeling varnish layer that weakens the heat seal strength is partially formed. This is a liquid paper container.

  Further, in the invention according to claim 5, the sealing part for heat fusion connected to one end of the hollow tubular portion of the stopper attached to the liquid paper container is made of at least a polyolefin-based resin, polybutene-1, poly (ethylene -Butene), and a plug made of a resin composition blended with one or more low crystalline rubber components selected from poly (propylene-butene) is attached by fusing the heat-sealing seal part to the sealant layer. The liquid paper container according to claim 3 or 4, wherein the liquid paper container is provided.

  The liquid paper container according to the present invention is a liquid paper container formed by molding a paper-based laminate having at least a surface resin layer on the front surface and at least a gas barrier layer and a sealant layer on the back surface. Recyclable paper is the main raw material, and there is little burden 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.

  In the liquid paper container according to the present invention, the surface resin layer on the surface and / or the sealant layer on the inner surface is formed by blending a polyolefin resin with a low crystalline rubber component. Since the seal part cohesively breaks, it can be easily opened or disassembled by a human hand.

  When the polyolefin resin is a polyethylene resin and one or more selected from polybutene-1, poly (ethylene-butene) and poly (propylene-butene) are selected as the low crystalline rubber component, The most favorable result can be obtained in terms of demolition.

  When the liquid paper container according to the present invention is a gable top type liquid paper container, a release varnish layer that weakens the heat seal strength is partially formed on the surface resin layer on the surface side of the folded top seal portion. Thus, it is possible to improve the easy-opening property or the easy-disassembling property when the wife part is opened upon opening or dismantling. Moreover, since the peeling varnish layer can be provided on the surface side of the laminate simultaneously with printing, it can be easily provided at an accurate position without increasing the number of steps.

  Resin obtained by blending at least one low crystalline rubber component selected from polybutene-1, poly (ethylene-butene), and poly (propylene-butene) with a polyolefin-based resin at least in a sealing part for heat fusion of a spigot When the stopper made of the composition is attached, not only the container but also the stopper can be easily removed by hand when the container is disassembled after use.

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

Hereinafter, a laminate for a paper container and a liquid paper container according to the present invention will be described in detail with reference to the drawings.
1, 2, and 3 are schematic cross-sectional views showing examples of embodiments of a laminated body for paper containers according to the present invention.

  A laminate 20 for paper containers according to the present invention is a laminate based on paper 23 having at least a surface resin layer 22 on the surface and at least a gas barrier layer 25 and a sealant layer 27 on the back surface, The surface resin layer 22 and / or the sealant layer 27 is a laminate for a paper container, which is obtained by blending a polyolefin resin with a low crystalline rubber component.

  In the embodiment shown in FIG. 1, the surface resin layer 22, the ink layer 21 printed on the surface, and the release varnish application part 19 exist on the surface side of the paper 23. On the back side of the paper 23, a gas barrier layer 25 is laminated with an adhesive resin layer 24, and a gas barrier layer 25 and a sealant layer 27 are laminated with an adhesive layer 26.

  Next, an example of a procedure for actually producing the paper container laminate 20 shown in FIG. 1 will be described. For example, first, a sealant film obtained by blending 70 parts of polyethylene resin and 30 parts of polybutene-1 as a sealant layer 27 is laminated on the PET surface side of an aluminum-deposited PET film as the gas barrier layer 25 by a dry laminating method using an adhesive for dry laminating. Then, the vapor deposition surface side of the aluminum vapor-deposited PET film and the paper substrate 23 are laminated by an extrusion laminating method using polyethylene resin as the adhesive resin layer 24, and the surface resin layer is formed on the surface side which is the opposite surface of the paper. A low density polyethylene resin (LDPE) is extruded and laminated as 22. In this case, the aluminum vapor-deposited PET film may be turned upside down.

By printing the ink layer 21 and the release varnish coating part 19 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. Thus, a laminate 20 for a paper container having a layer structure as shown in FIG. 1 is obtained.

  In the process of manufacturing the paper container laminate 20, the bonding surface may be subjected to a surface activation treatment such as ozone treatment or corona treatment, or an anchor coating agent may be applied.

As the paper 23 serving as a 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 can be selected and used according to the size of the paper container. 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.

  As a characteristic material used for the paper container laminate 20 according to the present invention, a material obtained by blending a low crystalline rubber component with a polyolefin resin can be used as the surface resin layer 22 and / or the sealant layer 27. The base polyolefin resin is low density polyethylene resin (LDPE), medium density polyethylene resin (MDPE), high density polyethylene resin (HDPE), linear low density polyethylene resin (LLDPE), ethylene-α olefin copolymer Olefin resins such as polymers, homopolypropylene resins, propylene-ethylene random copolymers, propylene-ethylene block copolymers, propylene-α olefin copolymers, and modified polyolefins obtained by acid-modifying these olefin resins by graft polymerization or the like Resin can be used.

  Among the olefin resins, LDPE and LLDPE are most suitable. Low crystalline rubber components include polybutene resins such as polybutene-1, poly (ethylene-butene), poly (propylene-butene), ethylene-propylene copolymer (EPM), ethylene-propylene-diene ternary copolymer A synthetic rubber such as a polymer (EPDM) can be used. Most preferred among these are polybutene-1, poly (ethylene-butene), and poly (propylene-butene).

  The addition amount of the low crystalline rubber component is in the range of 10 to 60 parts by weight with respect to 100 parts by weight of the polyolefin resin, and is preferably about polyolefin resin 70: around the low crystalline rubber component 30. Since this material has a weak cohesive force, it causes cohesive failure relatively easily when a pulling force is applied during opening or disassembly. As the thickness when used as the surface resin layer 22, a range of 10 to 30 μm is appropriate. Moreover, as thickness when using as the sealant layer 27, the range of 40-100 micrometers is suitable.

  By using this material for either one or both of the surface resin layer 22 and the sealant layer 27 of the laminate 20, easy opening or easy disassembly is expressed in the paper container. When this material is used for either the surface resin layer 22 or the sealant layer 27, a general material usually used for these layers can be used if the other is not used.

  Common materials used for the surface resin layer 22 in this case 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 grafted with these olefin resins. A modified polyolefin resin modified with acid by polymerization or the like 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.

  Examples of the gas barrier resin film include an ethylene-vinyl alcohol copolymer film (EVOH), a polyvinyl alcohol film (PVA), a biaxially stretched PET film, a biaxially stretched nylon film and an EVOH laminated film, and an ethylene-vinyl acetate copolymer ( EVA) saponified products, polyvinylidene chloride films, 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 film such as PET, polyethylene naphthalate (PEN), polybutylene terephthalate (PBT), polyamide film such as PP, nylon-6, nylon-66, polycarbonate (PC ), Polystyrene (PS), polyacrylonitrile (PAN), polyimide (PI) and the like are used as non-stretched or stretched films.

  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, so-called no-anchor coat polyethylene resin such as epoxidized vegetable oil-containing polyethylene resin, ethylene / acrylic Acid copolymer resin (EAA), acid copolymer such as ethylene / methacrylic acid copolymer resin (EMAA), acid anhydride graft-modified polyethylene resin, ethylene / vinyl acetate copolymer resin (EVA), ethylene / ethyl acrylate copolymer A single resin such as a polymer resin, ethylene / methacrylic acid / methacrylic acid ester terpolymer resin, and ionomer resin, or co-extrusion of these resins and polyethylene resins 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, the above-mentioned blended resin of polyolefin resin and low crystalline rubber component is used alone or by coextrusion with polyethylene resin. The thickness is in the range of 40 to 100 μm. In the case of a coextruded film, the blend resin layer needs to have a thickness of 10 μm or more, the polyethylene resin layer needs to have a thickness of 20 μm or more, and the entire sealant layer preferably has a thickness of 40 μm or more.

  When the above-mentioned blend resin of polyolefin resin and low crystalline rubber component is used as the surface resin layer 22, a material generally used as a sealant layer can also be used as the sealant layer 27. Examples of these materials include LDPE, MDPE, LLDPE, ethylene / vinyl acetate copolymer, ethylene / α-olefin copolymer, ethylene-methacrylic acid resin copolymer (EMAA) and other ethylene-based resins, homopolypropylene, Polypropylene resins such as a propylene / ethylene random copolymer, a propylene / ethylene block copolymer, and a propylene / α-olefin copolymer are used.

  FIG. 2 is a schematic cross-sectional view showing another embodiment of the laminate for paper containers according to the present invention. In this embodiment, the paper 23 and the gas barrier layer 25 are laminated by extrusion lamination by coextrusion of EMAA 15 μm (24a) and polyethylene resin 15 μm (24b) as the adhesive resin layer 24. It is the same.

  FIG. 3 is a schematic cross-sectional view showing another embodiment of the laminate for paper containers according to the present invention. In this embodiment, as the sealant layer 27, except that a resin composition obtained by blending 70 parts of polyethylene resin with 30 parts of polybutene-1 and a sealant film obtained by coextruding polyethylene resin with a thickness of 30 μm were used, as shown in FIG. This is the same as the embodiment.

FIG. 4 is a perspective view showing an embodiment of the liquid paper container according to the present invention, and FIG. 5 is an explanatory plan view showing a state of the liquid paper container blank shown in FIG. 4 as viewed from the front side. It is.
The liquid paper container shown in FIG. 4 is a paper container having a gable roof type top that is generally called a gable top type. The gable roof has a gable portion formed by two triangular top plates 15, and the roof portion is formed by two rectangular top plates 14.

  To assemble the blank of FIG. 5, the four side plates 13 are formed into a square cylinder by folding the ruled line 11 between them, and then the bottom and the top are formed. In forming the top portion, two rectangular top plates constituting the roof portion are formed of two sets of triangular top plates 15 constituting the gable portion of the gable roof and the folding top seal portion 18 continuously provided on the upper portion of the folding triangular plate 16. 14 and heat-sealed with a top seal portion 17 provided on the upper portion of 14.

  In this embodiment, a release varnish application part 19 in which a release varnish layer that serves to weaken the heat seal strength is partially formed on the surface resin layer on the surface side of the folded top seal part 18 is provided. In this way, when opening the liquid paper container 1 of FIG. 4, the ends of the two rectangular top plates 14 can be opened along with the triangular top plate 15 with a small force. it can. Moreover, when the side opposite to the rectangular top plate is opened and disassembled after use, it can be opened with a small force.

  As the peeling varnish, a synthetic resin varnish such as an acrylic resin to which a small amount of a liquid repellent such as silicone oil is added can be used. The peeling varnish application part 19 can be provided by printing on the surface of the surface resin layer 22 to provide the ink layer 21 at the same time, so there is no great difficulty in alignment, etc. If coloring is performed, registration at the time of printing becomes easy.

6 is a perspective view showing another embodiment of the liquid paper container according to the present invention, and FIG. 7 is a plan view showing a state of the liquid paper container blank shown in FIG. 6 viewed from the front side. FIG.
The liquid paper container shown in FIG. 6 is a gable top type liquid paper container with a cap 3. One rectangular top plate 14 out of the two rectangular top plates is provided with a plug attachment hole 12 to which the plug 3 is attached. Also in this embodiment, on the surface resin layer on the surface side of the folded top seal portion 18, a release varnish application portion 19 in which a release varnish layer that serves to weaken the heat seal strength is partially formed is provided.

  8A and 8B are perspective views showing other embodiments of the liquid paper container according to the present invention. FIG. 8 (1) is a liquid paper container called a brick type or a flat top type, and FIG. 8 (2) is a liquid paper container with a stopper to which a stopper 3 is attached. By using the paper container laminate according to the present invention, easy opening and disassembly can be imparted to the paper containers of these forms.

FIG. 9 is a cross-sectional explanatory view of the plug portion of the liquid paper container according to the present invention. The spigot 3 attached to the liquid paper container according to the present invention has at least a heat-sealing seal portion 4 connected to one end of the hollow tubular portion at least in a polyolefin-based resin, polybutene-1, poly (ethylene-butene), It can consist of a resin composition blended with one or more low crystalline rubber components selected from poly (propylene-butene). In order to attach the plug 3 to the liquid paper container, the plug is inserted into the plug mounting hole 12 provided in the laminate 20, and the heat sealing seal 4 is fused to the sealant layer 27 of the laminate 20. And attach.

  When such a plug 3 is used, it becomes possible to easily remove the plug 3 from the laminate 20 by hand at the time of disassembly after use.

  The polyolefin resin used for the stopper is most preferably a polyethylene resin such as LDPE or LLDPE.

In the embodiment shown in FIG. 9, only the heat-sealing seal part 4, which is a part in contact with the sealant layer of the flange part of the plug 3, is added to the polyolefin-based resin with polybutene-1, poly (ethylene-butene), poly It consists of a resin composition blended with one or more low crystalline rubber components selected from (propylene-butene), but the entire plug 3 is made of any one of these resin compositions. May be.
Hereinafter, the laminate for a paper container and the liquid paper container according to the present invention will be described more specifically based on examples.

In accordance with the layer configuration shown in FIG. 1, a milk base paper having a basis weight of 400 g / m ² was used as the paper 23, and an aluminum vapor deposition film in which an aluminum vapor deposition layer was formed on a PET film having a thickness of 12 μm was used as the gas barrier layer 25. As the sealant layer 27, a film having a thickness of 60 μm made of a resin composition in which 70 parts of LDPE and 30 parts of polybutene-1 were blended was used. First, the aluminum vapor deposition film and the sealant layer were bonded together by a dry laminating method using an adhesive. Next, as the adhesive resin layer 24 for bonding the aluminum vapor-deposited film and the paper 23, LDPE having a thickness of 30 μm was extruded and both were laminated. Further, LDPE having a thickness of 20 μm was extrusion laminated on the surface of the milk base paper, and the ink layer 21 and the release varnish application part 19 were formed by a printing machine. Using the thus obtained laminate, a gable top type liquid paper container as shown in FIG. 4 was produced.

  According to the layer structure shown in FIG. 2, as an adhesive resin layer 24 for bonding the aluminum vapor-deposited film and paper 23, EMAA (paper side) with a thickness of 15 μm and LDPE (vapor-deposited film side) with a thickness of 15 μm are coextruded. A liquid paper container was produced in the same manner as in Example 1 except that lamination was performed.

  Example 1 except that a sealant layer 27b obtained by blending 30 parts of polybutene-1 with 70 parts of LDPE and a coextruded LDPE 27a with a thickness of 30 μm each was used as the sealant layer 27 in accordance with the layer structure shown in FIG. In the same manner, a liquid paper container was produced.

  A gas barrier layer using a 12 μm thick PET film and a 7 μm thick aluminum foil bonded together is used. As a sealant layer, LDPE is mixed with 70 parts of polybutene-1 and LDPE with a thickness of 30 μm each. The sealant film coextruded with was used. First, an aluminum foil laminated PET film and a sealant layer were bonded together by a dry laminating method using an adhesive. Next, as an adhesive resin layer for bonding the aluminum foil laminate film and paper, LDPE having a thickness of 30 μm was extruded and laminated. In the same manner, a liquid paper container was produced.

  A liquid paper container was used in the same manner as in Example 4 except that a sealant layer in which 70 parts of LDPE was blended with 30 parts of poly (propylene-butene) and a sealant film in which LDPE was coextruded with a thickness of 30 μm were used as the sealant layer. Was made.

A base paper of milk with a basis weight of 400 g / m ² is used as paper, a PET film with a thickness of 12 μm and an aluminum foil with a thickness of 7 μm are used as a gas barrier layer, and a single LDPE film with a thickness of 60 μm as a sealant layer. It was used. First, an aluminum foil laminated PET film and a sealant layer were bonded together by a dry laminating method using an adhesive. Next, as an adhesive resin layer for bonding the aluminum foil laminate film and paper, LDPE having a thickness of 30 μm was extruded and laminated. On the surface of the milk base paper, a film having a thickness of 20 μm made of a resin composition obtained by blending 70 parts of LDPE with 30 parts of polybutene-1 was extrusion laminated. The release varnish was not printed. Using the thus obtained laminate, a gable top type liquid paper container as shown in FIG. 4 was similarly produced.
<Comparative Example 1>

A milk base paper having a basis weight of 400 g / m ² was used as paper, and an aluminum vapor deposition film in which an aluminum vapor deposition layer was formed on a PET film having a thickness of 12 μm was used as a gas barrier layer. As the sealant layer, a single LDPE film having a thickness of 60 μm was used. First, the aluminum vapor deposition film and the sealant layer were bonded together by a dry laminating method using an adhesive. Next, as an adhesive resin layer for bonding the aluminum vapor-deposited film and paper, EMAA resin having a thickness of 30 μm was extruded and laminated. On the surface of the milk base paper, LDPE having a thickness of 20 μm was extrusion laminated, and an ink layer and a release varnish application portion were formed by a printing machine. Using the thus obtained laminate, a gable top type liquid paper container as shown in FIG. 4 was produced.

  A laminate was prepared in the same manner as in Example 1 except that an inorganic oxide vapor deposition film in which a silicon oxide vapor deposition film was formed on a PET film having a thickness of 12 μm was used as a gas barrier layer. A liquid paper container with a stopper as shown in FIG. 6 was prepared using a stopper formed using a resin composition in which 10 parts of the resin composition was blended.

  Except for using an inorganic oxide vapor deposition film in which an aluminum oxide vapor deposition film is formed on a 12 μm thick PET film as a gas barrier layer, and using a 60 μm thick sealant film in which 90 parts of LDPE is blended with 10 parts of polybutene-1 as a sealant layer. A laminate was prepared in the same manner as in Example 1, and a plug formed using a resin composition in which 70 parts of polyethylene resin was blended with 30 parts of polybutene-1 as the plug was shown in FIG. A liquid paper container with a stopper was prepared.

  A laminate was prepared in the same manner as in Example 3, and a mouthpiece formed using a resin composition in which 90 parts of LDPE was blended with 10 parts of polybutene-1 was used as a mouthpiece, as shown in FIG. A liquid paper container with a stopper was prepared.

Thickness comprising a resin composition in which a PET film having a thickness of 12 μm and an aluminum foil having a thickness of 7 μm are used as a gas barrier layer, and 70 parts of LDPE is blended with 30 parts of poly (propylene-butene) as a sealant layer. A laminated body was prepared in the same manner as in Example 1 except that a 60 μm film was used, and a plug formed using a resin composition in which 90 parts of LDPE was blended with 10 parts of poly (propylene-butene) as a plug. In use, a liquid paper container with a stopper as shown in FIG. 6 was produced.

A gas barrier layer using a 12 μm thick PET film and a 7 μm thick aluminum foil bonded together, a sealant layer using a 60 μm thick LDPE single film, and the surface of the paper as a surface resin layer, A laminate was prepared in the same manner as in Example 1 except that a 20 μm thick film made of a resin composition obtained by blending 30 parts of polybutene-1 with 70 parts of polyethylene resin, and 70 parts of polyethylene resin was used as a plug. A liquid paper container with a stopper as shown in FIG. 6 was prepared using a stopper formed using a resin composition obtained by blending 30 parts of polybutene-1.
<Comparative example 2>

  A laminated body was prepared in the same manner as in Example 1 except that a 60 μm thick LDPE single film was used as the sealant layer, and a plug formed using the LDPE simple substance as a plug was shown in FIG. A liquid paper container with a stopper was prepared.

  Each of the paper containers of Examples and Comparative Examples was filled with water and sealed, and then evaluated for easy opening, easy disassembly, easy plug separation, and transportability. The evaluation of easy opening, easy disassembly, and easy plug separation is a comparative evaluation based on sensory evaluation, and the evaluation of transportability is based on an erecting 80 cm, five drop test. The capacity of the containers is all 2 liters. The evaluation results are shown in Table 1.

  From the results in Table 1, the liquid paper container according to the present invention is superior in easy opening, easy disassembly, and easy plug separation as compared with Comparative Examples 1 and 2 corresponding to conventional paper containers. I understand that.

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

DESCRIPTION OF SYMBOLS 1 ... Paper container 2 ... Container main body 3 ... Plug 4 ... Sealing part 10 for heat fusion ... Blank 11 ... Ruled line 12 ... Plug attachment hole 13 ... Side plate 14 ... Rectangular top plate 15 ... Triangular top plate 16 ... Folding triangular plate 17 ... Top seal part 18 ... Folding top seal part 19 ... Peeling varnish application part 20 ... For paper containers Laminate 21 ... Ink layer 22 ... Surface resin layer 23 ... Paper 24, 24a ... Adhesive resin layer 24b, 27a ... Polyethylene resin layer 25 ... Gas barrier layer 26 ... Adhesive Layer 27, 27b ... sealant layer

Claims (5)

  A paper-based laminate having at least a surface resin layer on the front surface and at least a gas barrier layer and a sealant layer on the back surface, wherein the surface resin layer and / or the sealant layer is low crystalline in a polyolefin resin. A laminate for paper containers, characterized in that it is obtained by blending a functional rubber component.   The polyolefin resin is a polyethylene resin, and the low crystalline rubber component is at least one selected from polybutene-1, poly (ethylene-butene), and poly (propylene-butene). Item 2. A laminate for paper containers according to Item 1.   A liquid paper container obtained by molding the laminate for paper containers according to claim 1 or 2 so that the surface of the laminate is outside the container.   A gable top type liquid paper container having a gable roof type top formed by molding the laminate for paper containers according to claim 1 or 2 so that the surface of the laminate is outside the container, Two tops of triangular top plates that make up the gables of the gable roof and the top seals that are connected to the tops of the folding triangular plates are connected to the top of the two rectangular top plates that make up the roof. A liquid paper container, wherein a release varnish layer that weakens the heat seal strength is partially formed on the surface resin layer on the surface side of the folded top seal portion.   At least a sealing part for heat fusion connected to one end of a hollow tubular part of a stopper attached to a liquid paper container is made of at least a polyolefin-based resin from polybutene-1, poly (ethylene-butene), poly (propylene-butene). 5. A plug made of a resin composition blended with at least one selected low crystalline rubber component is attached by fusing the seal portion for heat fusion to a sealant layer. Liquid paper container as described in 1.