JP2007210640A - Pull-tab, paper container having pull-tub, and beverage in paper container - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a pull-tab having excellent fragrancy retaining properties and excellent peelability. <P>SOLUTION: In the pull-tab, an opening part 11 is formed in a container base material 10 having a heat seal on an outermost surface of a paper base material, the opening part is covered by a pull-tab seal 20 from the outer side of the container and by an inner film from the inner side of the container. The pull-tab seal comprises the paper base material, a light blocking layer, a gas barrier layer and a heat seal layer from the outer side of the container, and the inner film comprises a polyolefin layer, a gas barrier layer and a heat seal layer from the inner side of the container. The configuration is excellent in gas barrier properties, capable of maintaining, in particular, the fragrance of articles of taste, and excellent in peelability. The pull-tab can be peeled without any residue of the film. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a pull tab that has excellent aroma retention and is easy to peel off, a liquid paper container having the pull tab, and a beverage in a paper container in which a liquid beverage is filled with a liquid beverage.

  Conventionally, a so-called pull tab-equipped paper container in which the opening for drinking is covered with a pull tab seal for opening has been used for fruit juice drinks, coffee drinks, liquid soups, etc. for ease of use and disposal after use. Widely used in the field of liquid food.

  Such a pull tab is covered with a pull tab seal for opening so as to cover an opening provided in a container lid or the like, and the container main body is generally made of a paper base material. Therefore, when filling the liquid contents into such a paper container, if the end face of the opening is exposed, the contents penetrate into the inside from the end face during filling and storage, and the container is deformed. Or sanitation. In addition, since the innermost layer of the pull tab seal comes into contact with the contents of the container, the contents may permeate depending on the type of the adhesive layer to be used, and the adhesive strength of the adhesive layer may be reduced. When the adhesive strength of the adhesive layer is reduced in this way, even if the pull tab seal is pulled up at the time of opening, only the pull tab seal is separated while the inner tape and the contact layer remain in the opening of the container, and the opening is not opened. Not only does it fail to perform its function, it also detracts from aesthetics. On the other hand, it is desirable that the pull tab is firmly welded during storage or distribution and is heat-welded with such a strength that it can be easily peeled off during use. Various developments have been made to ensure such liquid-tightness during storage and easy peelability during use.

  For example, in the pull tab that seals the opening provided in a part of the container, the inner tape provided on the inner surface of the container is made of a heat-meltable resin film, and the outer tape provided on the outer surface of the container is from the inner tape side. There is a pull tab characterized in that an adhesive layer made of a heat-meltable resin, a copolymer with an unsaturated monomer containing an ethylene / carboxyl group, and an aluminum foil are laminated in order (Patent Document 1). . The pull tab is a pull tab of a paper container used for sealing a pouring part of a filled packaging paper container such as sake, shochu, wine, whiskey, seasoning, juice, liquid detergent, hair setting liquid, emulsion wax, bathing agent, antifreeze liquid, etc. According to this publication, the pull tab of the paper container can prevent a decrease in the adhesive strength of the outer tape adhesive layer due to the contents filled with a fragrance, a medicinal component, alcohol, a surfactant, an alkaline component, etc. Sometimes it is removed with the inner tape and adhesive layer in the opening, resulting in a fully open pull tab.

Further, for example, a pull tab formed by laminating a paper layer / reinforcing layer / sealant layer in order from the outside, at least a sealant layer / stretched polyethylene terephthalate film (PET), a stretched high-density polyethylene film (OHDPE), and a stretched polypropylene film in order from the outside. A pull tab is disclosed which is heat-sealed between sealant layers at the opening of a top panel formed by laminating a strength layer / barrier layer / paper layer / adhesive layer such as (OPP) and stretched nylon film (ONY). (Patent Document 2). In this publication, when the pull tab is peeled off, the paper peels off at the peeling surface around the opening, the paper fibers often appear on the peeling surface or the edge of the opening, and interface peeling may occur on the pull tab side, On the other hand, the sealant layer of the pull tab is taken to the top panel side and remains in the opening, and solves the problem that the opening is not exposed. According to the above configuration, when the pull tab is peeled off, it always peels from the peeling interface. The peeling force does not adversely affect the other layers, and there is no occurrence of paper fluff, aluminum surface waving, paper layer lifting, aluminum layer lifting, etc. There is a plastic surface oriented in the same direction as the direction, which strengthens the tensile strength and interlaminar fracture resistance of the strength layer. Part can be obtained, that.
JP-A-6-263159 JP 7-33143 A

  However, in the pull tab described in Patent Document 1, since the end surface of the paper base material comes into contact with the contents, it is impossible to prevent paper odor from being transferred to the contents.

  In addition, the method described in Patent Document 2 requires a pretreatment called a corona discharge treatment of OPE in order to adjust the adhesive force at the peeling interface, and the manufacturing process is complicated.

  Further, the pull tab described in the above-mentioned patent publications 1 and 2 may not have a sufficient protection function depending on the type of contents to be filled. In particular, when a flavor is leaked from the vicinity of a pull tab in the case of a highly-preferred coffee beverage or the like, it is also necessary to shorten the quality assurance period. In addition, in the manufacturing process of beverages in paper containers, there are few problems when a tab is provided on the container lid, and the container is sealed by fitting the lid after filling the container body with beverage, When the lid provided with the pull tab is attached to the paper container main body and the beverage is filled into the paper container, the pull tab and the beverage come into contact with each other from the filling process, so that the structure of the pull tab particularly affects the beverage contained in the paper container. large.

  In view of the above-mentioned present situation, an object of the present invention is to provide a pull tab that is excellent in sealing performance of contents.

  Another object of the present invention is to provide a pull tab having no film residue on the peeling surface and the opening edge of the pull tab at the time of peeling.

  As a result of examining the pull tab of the liquid paper container in detail, the present inventors have provided a light blocking layer and a gas barrier layer on the pull tab seal, and provided an inner film to prevent paper odor from being transferred to the contents and provide a high barrier property. The present invention is completed by finding that it can be made into a pull tab and that when the heat seal layer of the pull tab seal is adjusted to a specific thickness, it becomes a pull tab excellent in releasability without pretreatment such as corona discharge treatment. I let you.

  According to this invention, since it is excellent in gas barrier property, even if it uses it for the paper container of a liquid drink with especially high palatability, a flavor can be maintained over a long term.

  In the present invention, the layers constituting the pull tab can be laminated without pre-treatment to prepare the pull tab, so that the manufacturing efficiency is excellent.

  Since the pull tab of the present invention is excellent in releasability, the pull tab can be peeled off with an appropriate force, and only the peeled portion can be beautifully peeled off at the peeling interface, and the commercial value can be further increased.

  In addition, if a release agent made of a mixed resin of silicone resin and cellulose resin is used on the heat seal layer of the pull tab seal, the release agent can be applied without corona treatment, and the corona treatment step can be eliminated. Can do.

  In the first aspect of the present invention, an opening is provided in a container substrate having a heat seal layer on the outermost surface of the paper substrate, the opening is covered with a pull tab seal from the outside of the container, and an inner film is formed from the inside of the container. A pull tab for covering, wherein the pull tab seal includes a paper base, a light shielding layer, a gas barrier layer, and a heat seal layer from the outside of the container, and the inner film is formed from the inside of the container from the polyolefin layer, the gas barrier layer, and the heat seal layer. This is a pull tab. The pull tab of the present invention may be provided on any of the container lid, the container bottom, and the like in addition to the container main body of the liquid paper container. FIG. 1 will be described with reference to FIG. 1 showing a cross-sectional view of a pull tab provided on a container lid, which is a preferred example of an embodiment of the present invention.

  As shown to Fig.1 (a), as for the pull tab of this invention, a pull tab seal (20) and an inner film (30) are laminated | stacked from the upper and lower sides so that the opening part (11) of a container base material (10) may be covered. The structure is adhered by heat sealing as shown in FIG. 1B, leaving a part of the pull tab seal.

(1) Pull tab seal The pull tab seal (20) used in the present invention is a laminated film formed by laminating at least a paper base material with a light shielding layer, a gas barrier layer, a polyolefin layer, and a heat seal layer.

As the paper base material, any material that retains formability, bending resistance, rigidity, etc. as a liquid paper container may be used. -Paper base materials such as paper, kraft paper, paperboard and processed paper, and the like can be used. As the paper substrate, one having a basis weight of 40 to 150 g / m ² , more preferably 50 to 100 g / m ² is used. The paper base material preferably has a tensile strength and is difficult to delaminate, and a bleached craft of 50 to 100 g / m ² is suitably used for a pull tab seal.

  The light shielding layer is a foil made of aluminum, iron, stainless steel, zinc, gold, silver, copper, or an alloy thereof, and aluminum foil is mainly used. The thickness of the light shielding layer is desirably 3 to 20 μm, particularly 5 to 10 μm. Since the aluminum foil also has barrier properties such as oxygen gas and water vapor, it is particularly preferable to use the aluminum foil in the present invention.

  The gas barrier layer may be organic or inorganic, and examples of the organic type include polyethylene resins, polypropylene resins, cyclic polyolefin resins, fluorine resins, polystyrene resins, ethylene vinyl alcohol copolymers, acrylonitrile-styrene copolymers. Polymer (AS resin), Acrylonitrile butadiene-styrene copolymer (ABS resin), Polyvinyl chloride resin, Fluorine resin, Poly (meth) acrylic resin, Polycarbonate resin, Polyester such as polyethylene terephthalate, polyethylene naphthalate Resins, polyamide resins such as various nylons, polyimide resins, polyamideimide resins, polyarylphthalate resins, silicone resins, polysulfone resins, polyphenylene sulfide resins, polyethersulfurs Resins, polyurethane resins, acetal resins, cellulose resins, etc. More specifically, ethylene-vinyl alcohol copolymer (EVOH), acrylonitrile copolymer resins, stretched polyethylene terephthalate film (PET), stretched nylon film Various resins such as (ONY), unstretched nylon film (MXD6NY), polycarbonate, stretched polypropylene, stretched high-density polyethylene film (OHDPE), and stretched polypropylene film (OPP) can be used. Among them, an ethylene vinyl alcohol copolymer such as an ethylene-vinyl alcohol copolymer (EVOH) or a polyamide resin can be preferably used.

  As an inorganic system, there is a film in which an inorganic compound is deposited on a base resin. As a base resin that can be used as such a vapor-deposited film, it has excellent properties in mechanical, physical, chemical, etc., and in particular, it is a resin that has strength and toughness and heat resistance. Films or sheets can be used. Specifically, polyolefin resin such as polyethylene, polypropylene, polybutene, cyclic polyolefin resin, fluorine resin, polystyrene resin, acrylonitrile-styrene copolymer (AS resin), acrylonitrile butadiene-styrene copolymer (ABS resin) ), Polyvinyl chloride resins, fluorine resins, poly (meth) acrylic resins, polycarbonate resins, polyester resins such as polyethylene terephthalate and polyethylene naphthalate, polyamide resins such as various nylons, polyimide resins, polyamides Imide resin, polyaryl phthalate resin, silicone resin, polysulfone resin, polyphenylene sulfide resin, polyethersulfone resin, polyurethane resin, acetal resin, cellulose It can be used films or sheets of various resins of butter, and the like. These resin films or sheets may be stretched uniaxially or biaxially. If necessary, the base resin may be subjected to a surface smoothing treatment or the like by coating the surface thereof with an anchor coating agent or the like.

Further, as the inorganic oxide that can be vapor deposited, it can be used as long as it is basically a thin film obtained by making a metal oxide amorphous. For example, silicon (Si), aluminum (Al), Magnesium (Mg), calcium (Ca), potassium (K), tin (Sn), sodium (Na), boron (B), titanium (Ti), lead (Pb), zirconium (Zr), yttrium (Y), etc. It is possible to use a thin film obtained by making the metal oxide amorphous. Suitable examples of the liquid paper container include a thin film obtained by making an oxide of a metal such as silicon (Si) or aluminum (Al) amorphous. By the way, a thin film obtained by making the above metal oxide amorphous (amorphous) can be referred to as a metal oxide such as silicon oxide, aluminum oxide, magnesium oxide, etc. SiO _X, AlO _X, MO _X (in the formula, M represents a metal element, the value of X is in the range respectively of a metal element different.) as such MgO _X represented by. Moreover, as a range of said X value, silicon (Si) is 0-2, aluminum (Al) is 0-1.5, magnesium (Mg) is 0-1, calcium (Ca) is 0 to 1, potassium (K) is 0 to 0.5, tin (Sn) is 0 to 2, sodium (Na) is 0 to 0.5, boron (B) is 0 to 1, 5, Titanium (Ti) can take values in the range of 0-2, lead (Pb) in the range of 0-1, zirconium (Zr) in the range of 0-2, and yttrium (Y) in the range of 0-1.5. In the above, when X = 0, it is a complete metal and is not transparent and cannot be used at all. The upper limit of the range of X is a completely oxidized value. In the present invention, as a liquid paper container, generally, examples other than silicon (Si) and aluminum (Al) are poor, and silicon (Si) is 1.0 to 2.0, aluminum (Al ) Having a value in the range of 0.5 to 1.5 can be used. In the present invention, the film thickness of the inorganic oxide thin film as described above varies depending on the type of metal or metal oxide used, for example, about 50 to 3000 mm, preferably about 100 to 2000 mm. It is desirable to select and form arbitrarily within the range. Further, in the present invention, the inorganic oxide thin film may be not only one layer of the inorganic oxide thin film but also a laminated body in which two or more layers are laminated. As the oxide, an inorganic oxide thin film may be used which is used in one kind or a mixture of two or more kinds and mixed with different materials.

  In order to form an inorganic oxide thin film on a base resin, a physical vapor deposition method (PVD method) such as a vacuum deposition method, a sputtering method, an ion plating method, or a plasma chemical vapor deposition method, Examples thereof include a chemical vapor deposition method (CVD method) such as a thermal chemical vapor deposition method and a photochemical vapor deposition method. In the present invention, it is preferable to use PET as the gas barrier layer among the above. If the pull tab seal is not strong at the time of peeling, the pull tab seal is cut, and if the pull tab seal is pulled in the peeling direction, the pull tab seal cannot be easily peeled off without proper tension and strength. PET is suitable for pull-tab seals because it has excellent gas barrier properties, excellent fragrance retention in flavor products, and has an appropriate strength and elasticity.

  As the heat seal layer, a film or sheet of polyolefin resin that can be melted by heat and fused to each other can be used. For example, low density polyethylene, medium density polyethylene, high density polyethylene, linear (linear) ) Low density polyethylene, polypropylene, ethylene-vinyl acetate copolymer, ionomer resin, ethylene-acrylic acid copolymer, ethylene-ethyl acrylate copolymer, ethylene-methacrylic acid copolymer, ethylene-methyl methacrylate copolymer Polyolefin resins such as polymers, ethylene-propylene copolymers, methyl pentene polymers, polybutene polymers, polyethylene or polypropylene with unsaturated carboxylic acids such as acrylic acid, methacrylic acid, maleic acid, maleic anhydride, fumaric acid and itaconic acid. Modified acid modification It can be used films or sheets of Li olefin resin, other resins. Among these, the polyethylene film may be uniaxially stretched or biaxially stretched, but is more preferably a biaxially stretched film. In the present invention, it is preferable to use polyethylene or polyethylene film. Low density polyethylene is preferable because of its excellent heat sealability and little film residue at the time of peeling. In particular, as described later, it has been found that when a low-density polyethylene film having a predetermined thickness is used as a heat seal layer, a pull tab having excellent peelability is obtained.

  In the present invention, the above-described various resins can be used as a film or a sheet and can be produced by laminating a pull tab seal. As a method for producing such a film or sheet, for example, one or more of the above-mentioned various resins are used, and film formation such as a melt extrusion method, a cast molding method, a T-die method, a cutting method, and an inflation method is used. A method of forming a film of the above-mentioned various resins independently using a chemical conversion method, a method of forming a multilayer coextrusion film using two or more types of resins, and two or more types of resins To produce a film or sheet of various resins by a method of forming a film by mixing before film formation, and if necessary, for example, a tenter method or a tubular method, etc. It is possible to use various resin films or sheets that are uniaxially or biaxially stretched.

  It should be noted that one or more of the above-mentioned various resins are used, and in forming the film, for example, film processability, heat resistance, weather resistance, mechanical properties, dimensional stability, antioxidant properties, slipperiness In addition, various plastic compounding agents and additives can be added for the purpose of improving and modifying mold release properties, flame retardancy, antifungal properties, electrical properties, strength, etc. A very small amount to several tens of percent can be arbitrarily added depending on the purpose. In the above, general additives include, for example, colorants such as lubricants, crosslinking agents, antioxidants, ultraviolet absorbers, light stabilizers, fillers, antistatic agents, lubricants, antiblocking agents, dyes, pigments and the like. Etc., and further, a modifying resin or the like can also be used.

  In the present invention, in order to produce the body member laminate or the bottom member laminate using the film or sheet prepared above or using the copolymer or resin described above, a wet lamination method, a dry laminate, A lamination method, a solventless dry lamination method, an extrusion lamination method, a T-die extrusion molding method, a coextrusion lamination method, an inflation method, a coextrusion inflation method, and the like can be used.

Examples of laminating adhesives include one-part or two-part cured or non-cured vinyl, (meth) acrylic, polyamide, polyester, polyether, polyurethane, epoxy, and rubber. In addition, other adhesives such as a solvent type, an aqueous type, and an emulsion type can be used. As a coating method of the laminating adhesive, for example, a direct gravure roll coating method, a gravure roll coating method, a kiss coating method, a reverse roll coating method, a fountain method, a transfer roll coating method, and other methods can be used. The coating amount is preferably in the range of 0.1 to 10 g / m ² (dry state), more preferably in the range of 1 to 5 g / m ² (dry state). In addition, for example, an adhesion promoter such as a silane coupling agent can be arbitrarily added to the laminating adhesive.

In the above, as the melt-extrusion adhesive resin, the heat-sealable resin that forms the heat-sealable resin layer described above can be used in the same manner, and low-density polyethylene, particularly linear low-density polyethylene, acid-modified It is preferred to use polyethylene. The film thickness of the melt-extruded resin layer by the above-described melt-extruded adhesive resin is preferably in the range of 5 to 100 μm, more preferably in the range of 10 to 50 μm. In the present invention, when the above lamination is performed, if it is necessary to obtain stronger adhesive strength, an adhesion improving agent such as an anchor coating agent can be coated. Examples of the anchor coating agent include organic titanium anchor coating agents such as alkyl titanates, isocyanate anchor coating agents, polyethyleneimine anchor coating agents, polybutadiene anchor coating agents, and other various aqueous or oil-based anchor coating agents. Can be used. In the present invention, the anchor coating agent is coated by roll coating, gravure coating, knife coating, dip coating, spray coating, or other coating method, and the solvent, diluent, etc. are dried to form the anchor coating agent layer. can do. The application amount of the anchor coating agent is preferably in the range of 0.1 to 5 g / m ² (dry state).

  In the present invention, one or more of the above-described resins are used and melt-extruded using an extruder or the like. For example, an anchor coat is applied to a paper base material on which a light shielding layer or a barrier layer is laminated. A film or sheet of resin is produced in advance by melt-extruding and laminating a melt-extruded resin layer through an agent layer or the like, or by using one or more of the above-described resins, and paper A heat-seal layer can be laminated | stacked by carrying out dry lamination lamination on the one surface of a base material via the adhesive layer for lamination.

  Moreover, in order to provide a trigger part (non-adhesive part) necessary for opening the pull tab, a release agent is generally used. However, when a conventional release agent is used, a corona is applied before applying the release agent. It is necessary to apply a surface treatment such as a treatment. For example, when using a release agent mainly composed of nitrocellulose, such as the trade name “CM” manufactured by The Inktec Co., Ltd., it is necessary to apply CM after performing corona treatment on PE. It was. On the other hand, when an aluminum foil is used for the barrier layer in the present invention, sparks are generated and corona treatment cannot be performed. Even in such a case, for example, when a product name “Polycoat P-81” manufactured by Dainippon Ink Co., Ltd. is used as a release agent, the release agent can be directly applied to the innermost heat seal layer. For this reason, since a release agent can be applied without performing a surface treatment such as a corona treatment, one step can be reduced, and the adhesion to the inner film can be improved. Examples of the release agent that can be used in the present invention include silicone resins, urethane resins, nitrified cotton (cellulose) resins, blend resins of nitrified cotton and urethane resins, blend resins of silicone resins and cellulose resins, and the like. Among these, a blend resin of a silicone resin and a cellulose-based resin can be applied without performing a corona treatment, which is preferable. As such a release agent, since “polycoat P-81” containing silicone resin and cellulose resin as main components and containing ethyl acetate or toluene as a solvent can be applied without performing corona treatment, Particularly preferred. The “polycoat P-81” can be applied onto PE or PE film by a printing machine, as in the case of ordinary ink.

  The preferred structure of the pull tab seal used in the present invention is, from the outside of the container, paper base / aluminum foil / PET / polyethylene as paper base / light shielding layer / gas barrier layer / heat seal layer, and adhesive layer or anchor. Specific embodiments including a coating layer include: paper base material / polyethylene (adhesive layer) / aluminum foil (light-shielding layer) / dry lamination adhesive (adhesive layer) / PET (gas barrier layer) / anchor coat layer / polyethylene ( Adhesive layer) / polyethylene film (heat seal layer). Extrusion-coated low density polyethylene (LDPE) can be used for the adhesive layer, and ionomer, ethylene methyl acrylate (EMA), and ethylene methyl methacrylate (EMMA) are used for adhesion between the aluminum foil and the paper substrate. May be used. In addition, as an adhesive for dry lamination and an anchor coat agent, any of those described above can be suitably used.

The thickness of each layer is a paper base; preferably 40 to 150 g / m ² , more preferably 50 to 100 g / m ² / polyethylene (adhesive layer); preferably 5 to 30 μm, more preferably 10 to 20 μm / aluminum foil. (Light-shielding layer); preferably 3 to 20 μm, more preferably 5 to 10 μm / dry lamination adhesive (adhesive layer) 5 to 6 μm / PET (gas barrier layer); preferably 5 to 30 μm, more preferably 10 to 20 μm / Anchor coat layer 2-3 μm / polyethylene (adhesive layer); preferably 5-30 μm, more preferably 10-20 μm / polyethylene film (heat seal layer); preferably 20-100 μm, more preferably 40-80 μm.

  Moreover, it may replace with a polyethylene film and the thing which extruded and laminated | stacked the low density polyethylene may be used. In this case, low density polyethylene can be extruded and laminated to the above thickness directly on the anchor coat layer.

  In particular, the pull tab of the present invention is coated with a pull tab seal and an inner film from above and below the opening and bonded by heat sealing, and the peelability of the inner film depends on the thickness of the heat sealing layer of the pull tab seal. It turned out to be influenced. When the thickness of the polyethylene layer used as heat seal is less than 40 μm, the heat seal layer of the pull tab seal is too thin, and the pulling force of the inner film laminated and heat sealed from the inside of the container is insufficient when pulling up the pull tab seal. The film residue may occur around the opening. On the other hand, even if it exceeds 100 μm, the peelability does not change and it is uneconomical.

(2) Inner film The inner film includes a polyolefin layer, a gas barrier layer, and a heat seal layer from the outside of the container. Examples of the polyolefin layer include polyolefin resins such as polyethylene, polypropylene, and polybutene. The polyolefin layer constitutes a layer that comes into contact with the contents of the container, and in the present invention, polyethylene can be suitably used because it is inexpensive and excellent in operability.

  The gas barrier layer can be appropriately selected from those described in the section of the gas barrier layer of the pull tab seal, and is preferably an organic gas barrier layer. Among these, an ethylene-vinyl alcohol copolymer (EVOH) is preferable. ), Acrylonitrile copolymer resin, stretched polyethylene terephthalate film (PET), stretched nylon film (ONY), unstretched nylon film (MXD6NY), polycarbonate, stretched polypropylene, stretched high-density polyethylene film (OHDPE), stretched polypropylene film (OPP) Particularly preferred is EVOH, an unstretched nylon film (MXD6NY). If the composition of the gas barrier layer is different from that of the pull-tab seal, the barrier properties are exhibited based on different functions, so that the gas barrier properties such as oxygen and water vapor are further improved.

  Also, the heat seal layer can be appropriately selected from those described in the section of the heat seal layer of the pull tab seal, and is preferably the same resin as the heat seal layer. This is because the use of the same kind of resin is particularly excellent in adhesiveness during heat sealing.

  Similarly to the pull-tab seal, the inner film can be laminated by a co-extrusion method, a thermocompression bonding method, an adhesive method (dry lamination method), a vacuum deposition method, or the like. Moreover, the inner film used by this invention may contain the adhesive bond layer similarly to the said pull tab seal.

  A preferable inner film configuration includes, for example, a polyethylene layer such as polyethylene / adhesive layer / a gas barrier layer such as EVOH / adhesive layer / a heat seal layer such as polyethylene from the outside of the container. As the adhesive layer, extrusion of polyethylene is suitable.

  The thickness of each layer is a polyolefin layer; preferably 10 to 50 μm, more preferably 15 to 25 μm / polyethylene (adhesive layer); preferably 1 to 10 μm, more preferably 1 to 5 μm / EVOH (gas barrier layer); -20 μm, more preferably 1-10 μm / polyethylene (heat seal layer); preferably 10-50 μm, more preferably 15-25 μm, and the inner film layer is 20-200 μm, more preferably 20-100 μm. . If the inner film layer is less than 40 μm, the contents may leak. On the other hand, if the inner film layer exceeds 100 μm, the sealing performance is not changed, which is uneconomical.

  For such an inner film, polyethylene is melted and used as an adhesive layer, a polyethylene film and an EVOH film are laminated by extrusion lamination, then polyethylene is melted and used as an adhesive layer, and polyethylene used as a heat seal layer It can be prepared by extruding and laminating between a film and the EVOH layer.

(3) Container base material There is no particular limitation on the configuration of the liquid paper container itself, as long as it includes at least a paper base material and has a heat seal on the outermost surface of the paper base material to be heat sealed with the pull tab seal and the inner film. Good. The feature of the present invention lies in the layer structure of the pull tab seal and the inner film constituting the pull tab. With the above structure, it is particularly excellent in ensuring the fragrance retention and there is no remaining of the inner film, and the pull tab is peeled off. It is because it is excellent in property.

  However, in order to ensure the fragrance retaining property of the liquid beverage having particularly high palatability by the configuration of the pull tab of the present invention, the container base is a heat seal layer, a light shielding layer, a paper base and a heat seal layer in order from the outside of the container. Is preferably laminated. The presence of the light shielding layer can prevent the contents from being altered by light. In addition, the heat seal layer has the same configuration as the inner film described above, and the inner film having the same configuration as the inner layer used for the container base is used for the inner film of the pull tab, thereby preventing the transfer of the paper odor of the contents. High barrier properties can be ensured.

  Therefore, each said layer can be selected from what was used with the above-mentioned pull tab and an inner film. The heat seal layer is preferably made of the same material as that of the pull tab and the inner film, and is preferably a polyolefin, more preferably polyethylene.

  The light-shielding layer used for the container base material is preferably an aluminum foil having a thickness of 3 to 20 μm, like the pull tab. This is because light of a wide wavelength can be blocked, and the quality retention is high.

As the paper base material, any material that retains formability, bending resistance, rigidity, etc. as a liquid paper container may be used. For example, a strongly sized bleached or unbleached paper base material, or pure white paper Paper substrates such as paper, kraft paper, paperboard, processed paper, etc. can be used. As the paper substrate, those having a basis weight of 80 to 350 g / m ² , more preferably 200 to 300 g / m ² are suitable.

  Also in the liquid paper container, each layer can be bonded by a co-extrusion method, a thermocompression bonding method, an adhesive method (dry lamination method), a vacuum deposition method, or the like. Therefore, in addition to the above, an adhesive layer may be further included. Therefore, it may be heat seal layer / adhesive layer / light-shielding layer / adhesive layer / paper substrate / heat seal layer from the outside to the inside of the container. On the other hand, when a heat seal layer is formed on the surface of the light shielding layer, an adhesive layer is not used. For example, after laminating an aluminum foil on a paper substrate by a dry lamination method, polyethylene is melted and laminated, and heat seal is performed. It is good also as a layer. The liquid paper container used in the present invention includes heat seal layer / light shielding layer / polyolefin such as polyethylene / paper substrate / heat seal layer, and more specifically polyolefin such as polyethylene / aluminum foil / adhesion. Layer / paper substrate / polyolefin layer such as polyethylene.

The thickness of each layer is polyethylene (heat seal layer); preferably 5 to 50 μm, more preferably 10 to 30 μm / aluminum foil (light shielding layer); preferably 3 to 20 μm, more preferably 5 to 10 μm / polyethylene (adhesive layer) Preferably 5 to 50 μm, more preferably 10 to 30 μm / paper substrate; preferably 100 to 370 g / m ² , more preferably 220 to 300 g / m ² / polyethylene (polyolefin layer); preferably 5 to 80 μm, More preferably, it is 10-50 micrometers. The paper base material preferably has a tensile strength and is difficult to delaminate, and cup base paper of 150 to 400 g / m ² is suitably used for the container base material.

  Such a container base is, for example, extruding polyolefin on the outside of a paper base, then laminating an aluminum foil, applying an anchor coating agent on the aluminum foil, further applying a polyolefin, On the other side, it can be prepared by extruding a polyolefin.

(4) Pull tab The pull tab of the present invention is provided with an opening in a container base material having a heat seal layer on the outermost surface of the paper base material, and the opening is covered with a pull tab seal from the outside of the container, and from the inside of the container. It can be prepared by coating with a film and bonding the pull tab seal and the inner film with a heat seal layer.

  In the pull tab of the present invention, the pull tab seal and the inner film are integrated by heat sealing treatment, and when peeling the pull tab, the inner film and the heat seal layer of the container base material are formed around the opening as the pull tab seal is pulled up. It is necessary to peel off while the inner film is laminated on the pull tab seal side. This peelability is a characteristic different from the light shielding property of the pull tab seal and the inner film, the gas barrier property, etc., and this peelability is extremely important for functioning as a pull tab. In the present invention, the structure of the pull tab seal and the inner film is as described above, so that even when used in a liquid beverage paper container having high palatability, it is excellent in quality retention and aroma retention, and the heat seal layer of the pull tab seal By using a polyethylene film and setting the thickness of each layer and the thickness of the laminated film within the above ranges, there is no film residue and extremely excellent peelability is ensured.

  In order to peel the pull tab seal from the opening provided in the lid of the container (40) simply and without film residue, for example, as shown in FIG. 2 (a), the opening (11) has a shape on the peeling start side. Is preferably pointed, but is not limited thereto. Further, the outer periphery (13) of the opening (11) is heat-sealed together with the inner film, while an unheat-sealed portion (21) is formed on the peeling start side.

(5) Liquid paper container Especially the pull tab of this invention can be used suitably for the pull tab of the paper container for liquid drinks. Since the container base material is laminated with the pull tab seal from the outside of the container and the inner film from the inside of the container, even if the end face is exposed by the opening provided in the container base material, the end face and contents are formed by the pull tab seal and the inner film. Can be avoided. Such pull tabs may be provided on the lid of the paper container, on the bottom, or on the side of the container. Further, the cylindrical body portion may be cylindrical, tapered, or inversely tapered. Since the liquid paper container of the present invention is particularly excellent in gas barrier properties and fragrance retention properties, it can be optimally used as a paper container for coffee and water drinks with high palatability.

  In order to manufacture a liquid paper container in which a pull tab is provided on the lid portion of the present invention, openings are previously provided at equal intervals in a long paper base material for the lid, and this paper base material is used as the container base material. The pull tab seal prepared in accordance with the above method and the inner film may be laminated so as to cover the opening, and heat sealing may be performed while leaving a part of the pull tab seal.

  In order to prepare a reverse-tapered liquid paper container using such a pull tab, a band-shaped laminate for lid members (50) provided with a pull tab in advance is prepared. On the other hand, a container base (not shown) necessary for making the body of the liquid paper container is punched into a predetermined shape to form a blank plate (61), which is then rolled into a cylindrical shape, The cylindrical cup body (65) is manufactured by partially overlapping and performing heat treatment such as hot air treatment on the overlapped portion. On the other hand, the lid part is manufactured by punching the strip-shaped laminate for lid member (50) into a circular shape so as to include the pull tab (20) to produce a disc (51) constituting the lid part, Standing up into a cylindrical shape to form an upright molding part (53), then inserting a lid into the manufactured cup body part (65), bending the bottom end of the body part toward the upright molding part side, Hot air or the like is blown onto the joint between the portion (65) and the lid (53) to heat and melt the heat-sealable resin layer. Next, the overlapping portion of the lid portion with the upright molding portion (53) is knurled from the inner diameter side to closely bond the cup body portion (65) and the lid portion (53) to form the lid seal portion (70). .

  The contents can be filled with the container upside down and with the lid on the bottom. After filling the contents, the bottom is attached in the same manner as the lid is attached in this state. In the case of a reverse-tapered container having a lid area smaller than the bottom area, filling the contents with the top and bottom reversed makes the filling operation easy because the area during filling is large. In addition, since the bottom portion having a larger area than the lid portion is attached after the contents are filled, the attaching operation of the bottom portion is facilitated.

(6) Beverage in paper container The beverage in a paper container of the present invention is a liquid container filled with a liquid beverage. Examples of such beverages include coffee, miso soup, liquid soup, fruit juice beverage, and water.

  EXAMPLES Next, although an Example is given and this invention is demonstrated concretely, these Examples do not restrict | limit this invention at all.

Example 1
(1) pull tab seal 1 (paper _{^{(80g / m 2) / PE}} 15 / Al 7 / DL / PET 12 / AC / PE 15 / PEF 30) mosquito Tatsuya kraft paper for producing substrates (basis weight 80 g / m ² ) In order from the substrate side, LDPE (Mitsui Chemicals, trade name “MR16P”; density: 0.923 g / cm ³ , melt index (MI): 3.7 g / 10 min, melting point ( DSC method): 111 ° C.) is extruded and laminated to a thickness of 15 μm, and an aluminum foil with a thickness of 7 μm is laminated thereon, and an adhesive (manufactured by Rock Paint Co., Ltd., trade name “RU-77T / H”) And a PET film having a thickness of 12 μm was further bonded. An anchor coating agent (trade name “A3210 / A3075” manufactured by Mitsui Takeda Chemical Co., Ltd.) was applied thereon. Next, the LDPE was laminated to a thickness of 15 μm on the anchor coating agent by extrusion, and an LDPE film having a thickness of 30 μm as an innermost layer (trade name “P204” manufactured by Tosoh Corporation); density: 0.923 g / cm ³ , MI: 7.0 g / 10 min, melting point (DSC method) 107 ° C.) were bonded together. Furthermore, Polycoat P-81 was applied as a release agent on the LDPE film.

(2) Production of inner film On both sides of EVOH having a thickness of 5 μm (trade name “E105B” manufactured by Kuraray Co., Ltd.), product name “NF-555” manufactured by Mitsui Chemicals; density: 0.913 g / cm ³ , MI: 4.2 g / 10 min, melting point (DSC method): 120 ° C. was applied at a thickness of 4 μm, and polyethylene was LDPE (trade name “MR16P” manufactured by Mitsui Chemicals, Inc.); density: 0.923 g / An inner film was manufactured by extruding and laminating cm ³ , melt index (MI): 3.7 g / 10 min, melting point (DSC method): 111 ° C. to a thickness of 18.5 μm.

(3) Production of pull tab Paper base: LDPE (manufactured by Tosoh Corporation, trade name “P204”; density: 0.923 g / cm ³ , MI: 7.0 g / 10 min, melting point (outside of 256 g / m ² ) DSC method) 107 ° C.) was extruded 18 μm, an anchor coating agent (trade name “A3210 / A30” manufactured by Mitsui Takeda Chemical Co., Ltd.) was applied on the LDPE, and an aluminum foil having a thickness of 15 μm was laminated thereon. Furthermore, LDPE (trade name “P204” manufactured by Tosoh Corporation, trade name “P204”; density: 0.923 g / cm ³ , MI: 7.0 g / 10 min, melting point (DSC method) 107 ° C.) with a thickness of 15 μm was applied. In addition, on the opposite side of the paper substrate, LDPE (trade name “P204” manufactured by Tosoh Corporation; density: 0.923 g / cm ³ , MI: 7.0 g / 10 min, melting point (DSC method) 107 ° C.) Was extruded to form a paper container lid. Next, an opening having a major axis of 7 to 9 mm and a minor axis of 3 to 5 mm was provided in the lid. The structure of the lid is PE ₁₅ / Al ₁₅ / AC / PE ₁₈ / paper (256 g / m ² ) / PE ₆₀ from the outermost layer (side to be brought into contact with the pull tab seal) toward the innermost layer (content side). Become.

  The pull tab seal 1 was laminated on the LDPE layer of the opening, the inner film was laminated on the cup base paper side, and fused at a temperature of 150 to 250 ° C. to produce a pull tab.

(Example 2)
(1) Production of pull tab seal 2 (paper (80 g / m ² ) / PE ₁₅ / Al ₇ / DL / PET ₁₂ / AC / PE ₁₅ / PEF ₄₀ )
Using craft paper (basis weight 80 g / m ² ) as a base material, in order from the base material side, LDPE (trade name “MR16P” manufactured by Mitsui Chemicals, Inc .; density: 0.923 g / cm ³ , MI: 3.7 g / 10 min, melting point (DSC method): 111 ° C.) is extruded and laminated to a thickness of 15 μm, and an aluminum foil having a thickness of 7 μm is laminated thereon, and an adhesive (manufactured by Rock Paint Co., Ltd.) , Trade name “RU-77T / H”) and a PET film having a thickness of 12 μm was further bonded. An anchor coating agent (trade name “A3210 / A3075” manufactured by Mitsui Takeda Chemical Co., Ltd.) was applied thereon. Next, the LDPE was laminated to a thickness of 15 μm on the anchor coating agent by extrusion, and an LDPE film having a thickness of 40 μm as an innermost layer (trade name “P204” manufactured by Tosoh Corporation); density: 0.923 g / cm ³ , MI: 7.0 g / 10 min, melting point (DSC method) 107 ° C.) were bonded together.

(2) Manufacture of pull tab An inner film was manufactured in the same manner as in Example 1.

  Next, a pull tab was manufactured in the same manner as in Example 1 except that the pull tab seal 2 was used instead of the pull tab seal 1.

(Example 3)
(1) Production of pull tab seal 3 (paper (60 g / m ² ) / PE ₁₅ / Al ₇ / DL / PET ₁₂ / AC / PE ₁₅ / PEF ₅₀ )
Using craft paper (basis weight 60 g / m ² ) as the base material, in order from the base material side, LDPE (trade name “MR16P” manufactured by Mitsui Chemicals, Inc .; density: 0.923 g / cm ³ , MI: 3.7 g / 10 min, melting point (DSC method): 111 ° C.) is extruded and laminated to a thickness of 15 μm, and an aluminum foil having a thickness of 7 μm is laminated thereon, and an adhesive (manufactured by Rock Paint Co., Ltd.) , Trade name “RU-77T / H”) and a PET film having a thickness of 12 μm was further bonded. An anchor coating agent (trade name “A3210 / A3075” manufactured by Mitsui Takeda Chemical Co., Ltd.) was applied thereon. Next, the LDPE was laminated to a thickness of 15 μm on the anchor coating agent by extrusion, and an LDPE film having a thickness of 50 μm as an innermost layer (trade name “P204” manufactured by Tosoh Corporation); density: 0.923 g / cm ³ , MI: 7.0 g / 10 min, melting point (DSC method) 107 ° C.) were bonded together.

(2) Manufacture of pull tab An inner film was manufactured in the same manner as in Example 1.

  Next, a pull tab was manufactured in the same manner as in Example 1 except that the pull tab seal 3 was used instead of the pull tab seal 1.

Example 4
(1) Production of pull tab seal 4 (paper (80 g / m ² ) / PE ₁₅ / Al ₇ / DL / PET ₁₂ / AC / ECPE ₅₀ )
Using craft paper (basis weight 80 g / m ² ) as a base material, in order from the base material side, LDPE (trade name “MR16P” manufactured by Mitsui Chemicals, Inc .; density: 0.923 g / cm ³ , MI: 3.7 g / 10 min, melting point (DSC method): 111 ° C.) is extruded and laminated to a thickness of 15 μm, and an aluminum foil having a thickness of 7 μm is laminated thereon, and an adhesive (manufactured by Rock Paint Co., Ltd.) , Trade name “RU-77T / H”) and a PET film having a thickness of 12 μm was further bonded. An anchor coating agent (trade name “A3210 / A3075” manufactured by Mitsui Takeda Chemical Co., Ltd.) was applied thereon, and then LDPE (manufactured by Nippon Polychem Co., Ltd., product name “LC600A”; density: 0) 919 g / cm ³ , MI: 7.0 g / 10 min, melting point (DSC method) 107 ° C.) were extruded and laminated to a thickness of 50 μm.

(2) Manufacture of pull tab An inner film was manufactured in the same manner as in Example 1.

  Next, a pull tab was manufactured in the same manner as in Example 1 except that the pull tab seal 4 was used instead of the pull tab seal 1.

(Comparative example)
(1) Manufacture of pull tab seal 5 (paper (80 g / m ² ) / PE ₁₅ / HDPEF ₄₀ / PE ₃₀ )
Using craft paper (basis weight 80 g / m ² ) as a base material, in order from the base material side, LDPE (trade name “MR16P” manufactured by Mitsui Chemicals, Inc .; density: 0.923 g / cm ³ , MI: 3.7 g / 10 min, melting point (DSC method): 111 ° C.) is extruded and laminated to a thickness of 15 μm, and HDPEF having a thickness of 40 μm (trade name “H-500s” manufactured by Aicero Chemical Co., Ltd.) is formed thereon. : Density: 0.950 g / cm ³ , MI: 1.5 g / 10 min, melting point (DSC method): 130 ° C.), then LDPE (trade name “MR16P” manufactured by Mitsui Chemicals, Inc.); Density: 0.923 g / cm ³ , MI: 3.7 g / 10 min, melting point (DSC method): 111 ° C.) were extruded and laminated to a thickness of 30 μm.

(2) Manufacture of pull tab An inner film was manufactured in the same manner as in Example 1.

  Next, a pull tab was manufactured in the same manner as in Example 1 except that the pull tab seal 5 was used instead of the pull tab seal 1.

(Example of characteristic evaluation)
About the pull tab manufactured in the said Examples 1-4 and the comparative example, barrier property, the inner surface film of a drinking mouth at the time of opening, and the peel strength at the time of opening with respect to a lid | cover were evaluated. In addition, the peel strength was measured using the pull tabs of Example 3 and Example 4. The evaluation method was as follows. The results are shown in Tables 1-3.

  (1) Barrier property: The oxygen transmission rate was measured by A method of JIS K7126 (1987), and the water vapor transmission rate was measured by B method. The light shielding property was determined by measuring the total light transmittance with a color meter designed based on JIS Z8722. The light transmittance was 0%, and the light transmittance was 100%.

  (2) Remaining film: It was evaluated how much film remained when the pull-tab seal was opened from the start portion as indicated.

  (3) Peel strength: With the pull tab seal adhered to the lid member laminate, the outer periphery of the pull tab is cut together with the lid member laminate to form a test piece. The pull tab non-adhesive portion of the test piece and the lid member laminate Were grabbed lightly with two grippers. As shown in FIG. 4, the test pieces were aligned so as to be parallel to the direction in which the load was applied, and then the gripping tool was applied. Thereafter, a tensile load was applied, and the maximum load while the pull tab seal finished peeling was read. As shown in FIG. 5, the part from the opening to the end of the drinking part was designated as A part, the part from the end of the drinking part to the last part of the pull tab seal adhesion was designated as B part, and the maximum load was evaluated as peel strength.

(result)
(1) The pull tabs of Examples 1 to 4 were all excellent in light shielding properties, oxygen barrier properties, and water vapor barrier properties.

  (2) The pull tabs of Examples 1 to 4 were judged to be practical because there was little or no film residue on the outer frame side and little or no film residue on the drinking mouth side.

  (3) When Example 3 and Example 4 are compared, it is better to use a polyethylene film as a heat seal layer than to use extruded polyethylene. Therefore, the peel strength can be reduced.

  The paper cup container of the present invention is excellent in light-shielding properties and fragrance retention properties and is particularly useful as a pull tab for beverages with high palatability.

(B) is a cross-sectional view of a pull tab, (a) is a figure explaining the process which has arrange | positioned the pull tab seal and the inner film above and below the opening part provided in the container base material. (A) is a top view of the cover part of the liquid paper container which provided the pull tab, (b) is a figure which shows the state which opened the pull tab. It is a figure which shows the process of manufacturing the liquid paper container concerning this invention. It is a figure which shows the tension state in the case of the peeling strength measurement of the pull tab manufactured in the Example. It is a figure which shows the evaluation location of the peel strength of the pull tab manufactured in the Example.

Explanation of symbols

10: Container base material,
11 ... opening,
13 ... the outer periphery of the opening,
20 ... Pull tab seal,
21 ... Unheat-sealed part of the pull tab seal,
30 ... inner film,
40 ... container,
50 ... Laminate for lid member,
51... Disc constituting the lid,
53 ... Standing molded part,
61 ... Blank board,
65 ... cup body,
70 ... seal part,
80 ... part A,
90 ... B part 100 ... gripping tool.

Claims (9)

  An opening is provided in a container substrate having a heat seal layer on the outermost surface of the paper substrate, the pull tab seal covers the opening from the outside of the container, and the pull tab covers the inner film from the inside of the container, The pull tab seal includes a paper base layer, a light shielding layer, a gas barrier layer, and a heat seal layer from the outside of the container, and the inner film includes a polyolefin layer, a gas barrier layer, and a heat seal layer from the inside of the container.   2. The pull tab according to claim 1, wherein the light shielding layer of the pull tab seal is made of an aluminum foil.   The pull tab according to claim 1 or 2, wherein the gas barrier layer of the pull tab seal is a polyethylene terephthalate layer.   The pull tab according to any one of claims 1 to 3, wherein the heat seal layer of the pull tab seal is a polyethylene film.   The pull tab of Claim 4 whose thickness of the heat seal layer of the said pull tab seal is 20-100 micrometers.   6. The pull tab according to claim 5, wherein the pull tab seal is coated with a release agent made of a mixed resin of silicone resin and cellulose resin on the heat seal layer.   The pull tab, wherein the container base material is formed by laminating a heat seal layer, a light shielding layer, a paper base material layer, and a heat seal layer in order from the outside of the container.   A liquid paper container having the pull tab.   9. A beverage in a paper container, wherein the beverage is filled in the liquid paper container described in 8 above.

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