JP2000168770A - Filling and packaging method for liquid food, and packaging material for paper container - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a paper container which is not affected by the temperature of a content to be filled, can obtain excellent seal, and has the fragrance keeping property or quality keeping property. SOLUTION: A packaging material for a paper container comprises at least an outermost thermoplastic material layer 21, a paper base layer 22, an adhesive thermoplastic material layer 23, a barrier layer 24, and an innermost thermoplastic material layer 26, the innermost thermoplastic material layer 26 has an extensive sealing characteristic capable of achieving the sealing at any temperature in the temperature range of at least 100-80 deg.C, and the barrier layer 24 and the innermost thermoplastic material layer 26 are joined with each other by the adhesive resin layer selected from ethylene vinyl acetate copolymer and ionomer.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for filling and packaging a liquid food and a packaging material for a paper container. In more detail, a continuous paper packaging material is formed into a tube in the longitudinal direction, and the tube-shaped packaging material is filled with a filling material such as fruit juice, tea, liquid dairy product, etc. Brick-shaped paper packaging container obtained by applying a horizontal line seal at predetermined intervals and cutting the packaging material along the horizontal line sealing portion, and cutting the paper packaging material into a predetermined shape, in the container longitudinal direction After obtaining the sealed blanks, sealing the bottom of the blanks, filling the filling of the liquid product from the upper opening, and sealing the upper part, the liquid food in the gable-top (roof type) paper packaging container obtained by sealing is obtained. The present invention relates to a filling and packaging method and a packaging material for a paper container.

[0002]

2. Description of the Related Art Packaging containers for milk, juice or other beverages are produced, for example, by forming a folded line of paper / plastic laminate into a tube by means of a longitudinal vertical line seal. The packing material is filled with the material to be filled, and a horizontal line seal is applied in the transverse direction of the tubular packaging material. First, it is formed into a cushion-shaped or pillow-shaped primary shape. It is cut individually at intervals and folded along the fold line to form the final shape. Examples of the final shape include a brick (parallel hexahedron), a polygonal prism exceeding a square, a hexagonal prism, an octagonal prism, a ten-prism prism, and a tetrahedron shape having four triangular surfaces.

Further, in the case of a gable-top (roof type) paper packaging container, the paper packaging material is cut into a predetermined shape, blanks sealed in the vertical direction of the container are obtained, and the bottoms of the blanks are sealed in a filling machine. It is obtained by filling milk, juice or other beverage filling material from the upper opening later and sealing the upper part. In these paper containers, the innermost layer of the packaging material corresponding to the horizontal line seal portion and / or the vertical seal portion is heat-sealed with the other innermost layer or outermost layer.

[0004]

The packaging laminate used in the conventional paper packaging container product is a low density polyethylene (LDPE) / printing ink layer / paper (fibrous) base material layer / L
DPE / Aluminum foil (Al) / LDPE / LDPE, LD
PE / printing ink layer / paper base layer / LDPE / LDPE,
Printing ink layer / LDPE / paper base layer / LDPE / LDP
E, LDPE / printing ink layer / paper base layer / LDP
E / Al / polyester (PET) and the like are known,
It is still widely used today.

However, the LD used here is
PE is a high-pressure low-density polyethylene, and the low-molecular-weight components contained in the innermost high-pressure low-density polyethylene migrate to the contents in the paper container, and the taste of the contents changes when stored for a long time. There is fear. Further, in an ethylene-α-olefin copolymer obtained using a Ziegler catalyst,
The sealing temperature is high and the processability is inferior. If a lubricant is added to improve the processability, the lubricant transfers to the contents and reduces the taste.

On the other hand, a paper container using an ethylene-α-olefin copolymer (so-called metallocene PE) polymerized by using a single-site catalyst in the innermost layer has been proposed (Japanese Patent Application Laid-Open No. 148895/1995). Kaihei 8-3
37237, JP-A-9-29868, JP-A-9-5
2299, JP-A-9-76435, JP-A-9-14
No. 2455, JP-A-9-86537, 9-76375
Issue publication). However, they do not necessarily show good performance in maintaining and maintaining flavor, taste, and flavor.

[0007] When the liquid food is, for example, citrus fruit juice or the like, in addition to fragrance and flavor retention,
Oxygen barrier properties are required. The liquid foods penetrate oxygen through the carton walls, thereby losing their nutritional value. It is common to add an aluminum foil layer to the laminate material to reduce oxygen ingress into the carton and minimize degradation of nutrients such as vitamin C. Although aluminum foil is effective as a barrier material, its use does not necessarily provide good adhesion to the innermost thermoplastic resin layer.

[0008] Various attempts have been made to develop practical alternatives to aluminum foil. It has excellent oxygen, gas and aroma barrier properties, yet is easily disposable after use. It has been conventionally proposed to use a vapor-deposited layer of an inorganic oxide for a packaging material for paper containers (Japanese Utility Model Publication No. 5-28190, Japanese Translation of PCT International Publication No. 8-500)
068, JP-A-6-93120). With such a packaging material having gas (oxygen) blocking properties, a paper container having fragrance retention properties or quality retention properties can be provided.
However, the packaging materials for paper containers do not have all the required performance.

[0009] In the process of packaging liquid food, the joint to be sealed is formed by extruded hot-melt resin in an extrusion laminate, the surface of which is contaminated with oxides at that temperature, and remains when filling and packaging liquid food. Liquid food contaminates its surface. It is important in the actual manufacturing process to optimally seal the packaging materials having such contaminants and contaminants present on the surface. In the above-mentioned conventional packaging material for liquid food paper containers, an optimal seal is obtained. It is difficult. In particular, the wrapping material including the continuous paper base layer with a fold line, the innermost layer at one end of the wrapping material and the outermost layer at the other end of the wrapping material are overlapped and longitudinally sealed and longitudinally sealed. The liquid food to be filled is filled into a tubular shaped packaging material, and the innermost layers of the tubular packaging material are joined to each other below the liquid surface of the liquid food at predetermined intervals in the transverse direction. Applying a horizontal line seal, cutting the packaging material along the horizontal line seal part to form a primary shape, folding along the fold line, for example, forming into a brick-like final shape by a filling packaging method to obtain a packaging container In this case, since the liquid food is bonded below the liquid surface, the liquid food always remains, the surface is contaminated, and it is difficult to obtain a good seal.

[0010] Further, since the liquid food to be filled has various quality and characteristics with respect to temperature, the temperature conditions at the time of filling and packaging this food vary widely, thus affecting the temperature of the filling contents. As a result, the sealing temperature varies over a wide range in the filling and packaging process. However, since the heat-adhesive resin in the conventional packaging material does not necessarily have a wide range of sealing properties, a good seal cannot be obtained due to the influence of the temperature of the filling contents.

[0011]

SUMMARY OF THE INVENTION The present invention has been made on the basis of the above-mentioned background, and an object of the present invention is to provide a good seal without being affected by the temperature of the filling contents, An object of the present invention is to provide a method for filling and packaging a liquid food and a packaging material for a paper container, which can provide a paper container having properties or quality retention properties.

[0012]

The above object is achieved by the present invention. That is, the packaging material for a paper container according to the present invention includes at least each of constituent layers of an outermost thermoplastic material layer, a paper base material layer, an adhesive thermoplastic material layer, a barrier layer, and an innermost thermoplastic material layer. A packaging material for a paper container in which each layer is laminated in the above-described order, wherein the innermost thermoplastic material layer has at least a portion to be sealed at any temperature within a temperature range of at least 100 ° C to 80 ° C. It has a wide-area sealing property capable of sealing, and the barrier layer and the innermost thermoplastic material layer are joined by an adhesive resin layer selected from an ethylene-vinyl acetate copolymer and an ionomer. Things.

[0013] The method of filling and packaging a liquid food according to the present invention comprises:
The following steps are included. A wrapping material including a continuous paper base layer with a fold line is overlapped with the innermost layer at one end of the wrapping material and the outermost layer at the other end, and longitudinally sealed to form a tube in the longitudinal direction. The liquid food to be filled is filled into the packaging material formed into a tube shape, and the innermost layers of the tubular packaging material are joined to each other below the liquid level of the liquid food, and a horizontal line seal is provided at predetermined intervals in the transverse direction. A packaging material is cut along the horizontal line seal portion to form a primary shape, and then folded along the fold line to form a final shape to obtain a packaging container, wherein at least the horizontal line seal portion or / In addition, the innermost layer of the packaging material corresponding to the vertical seal portion is made of a thermoplastic material having a wide-range sealing property capable of sealing at any temperature within a temperature range of at least 100 ° C to 80 ° C.

[0014]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The following describes how to implement the present invention. The packaging material for a paper container according to a preferred embodiment of the present invention includes an outermost thermoplastic material layer, a paper base material layer, an adhesive thermoplastic material layer, for example, a barrier layer made of aluminum, and an innermost thermoplastic material layer. At least, each of these layers is laminated in the above order. The paper substrate that can be used in the present invention is usually made of kraft pulp, and requires excellent strength and low water absorption.
The types are bleached paper (FBL), unbleached paper (UBL),
There are bleached and unbleached laminated paper (DUPLEX), clay-coated paper, and multilayer laminated paper (MB), and any of them in the present invention.

The adhesive resin layer that can be used in the present invention is made of ethylene-vinyl acetate copolymer (EVA).
And an ionomer selected from the group consisting of:
These film-forming layers are laminated as an adhesive layer using a synthetic resin of an ionomer (IO) in which the molecules of a vinyl acetate copolymer (EVA) or an ethylene-vinyl methacrylate copolymer are crosslinked with metal ions. . It is preferable to use an adhesive layer having a thickness of about 10 to 50 μm. Preferably, the adhesive layer is EVA or IO having a layer thickness of 10 to 18 μm.

The packaging material for a paper container according to the present invention can include at least an ink layer formed on the outer surface of the semi-material by printing or an ink layer formed on the outer surface of an outer resin layer having a sealing property. . Inks include aqueous or oil-based inks for flexographic printing, oil-based inks for gravure printing, curable inks for offset printing, and the like. In a preferred embodiment of the packaging material for paper containers of the present invention, the ink layer is the ink layer. And a component (for example, an imine-based component) that is partially common to the component included in the anchor agent layer that adheres to the adhesive layer.

In the embodiment of the packaging material for a paper container of the present invention,
Including a resin layer applied to the outer surface of the packaging material. The resin layer is, for example, a polyolefin resin such as polyethylene, polypropylene, and ethylene-based copolymer. In addition to the conventionally used low-density polyethylene (LDPE), resistance to contents (oil resistance, acid resistance, Linear low-density polyethylene (LLDPE) with excellent penetration resistance)
Examples include medium density polyethylene and coextruded films containing polyethylene.

In an embodiment of the packaging material for a paper container according to the present invention,
A barrier layer is provided on the inner laminate of the packaging material. The barrier layer is made of at least one selected from an aluminum foil, a metal / inorganic oxide thin film, an ethylene vinyl alcohol copolymer layer (EVOH layer), a nylon layer, a polyvinylidene chloride film, and a polyvinylidene chloride coated film.
Here, as the vapor-deposited film of the inorganic oxide as the barrier layer, for example, a thermoplastic resin film having a thickness of about 10 to 30 μm of polyolefin, nylon, polyester, polyvinyl alcohol, or the like is used for silicon oxide, tin oxide, or oxide. Thickness of 100 to 5000 by inorganic oxide such as zinc, indium oxide, titanium oxide, aluminum oxide
A thin film layer having a thickness of preferably about 200 to 1,000 is formed by vacuum deposition, sputtering, chemical vapor deposition, plasma chemical vapor deposition (PCVD), or the like.

As aluminum constituting the aluminum foil or aluminum thin film layer of the barrier layer, ordinary aluminum metal can be used. In this embodiment, as a method for forming the aluminum thin film layer, it can be formed by forming a vapor deposition film by a vacuum vapor deposition method such as an ion beam method or an electron beam method, a sputtering method, or the like. In the above, as the thickness of the aluminum thin film layer, in order to obtain a sufficient light-shielding property, usually,
It is preferably about 10 nm to 200 nm, and in particular,
In the present invention, about 20 to 150 nm is desirable. In the above description, as the thickness of the aluminum thin film layer increases, the total light transmittance decreases. However, when the light-shielding properties of the print layer and the like are not taken into consideration, the thickness of the aluminum thin film layer is 80%.
In nm, the total light transmittance is 0%. In the present invention, the thickness of the aluminum thin film layer can be adjusted according to the final packaging form, the presence / absence of the printed layer, the position where it is present, and the like, and the required physical properties.

The barrier layer that can be used in the present invention also includes a barrier film. The resin film constituting the film may be a resin film capable of forming an inorganic oxide vapor-deposited film or an aluminum vapor-deposited film, such as a polyethylene terephthalate film or a polybutylene terephthalate film. Polyester resin film, 6 nylon film, 66 nylon film, 610 nylon film,
612 nylon film, 11 nylon film, 12
Nylon film, polyamide resin film such as polyamide film by condensation of meta-xylene diamine and dibasic acid, polycarbonate resin film, polyolefin resin film such as polyethylene, polypropylene, etc., polyvinyl alcohol resin film , Ethylene-vinyl acetate copolymer film, polyvinyl chloride resin film, polyvinylidene chloride resin film, polystyrene resin film, poly (meth) acrylic resin film, polyacrylonitrile resin film, polyacetal resin Films, fluorine-based resin films, and other resin films can be used.

As the resin film, any one of an unstretched film and a stretched film stretched in a uniaxial or biaxial direction can be used.
The thickness of the film is 5 μm to 10 μm.
It is desirably about 0 μm, preferably about 10 μm to 30 μm. In the present invention, the film of the resin may be, if necessary, optionally subjected to a known pretreatment such as application of a silane coupling agent or the like, primer treatment, sandplast treatment, etc. The surface of the film can be adjusted.

Next, in the present invention, examples of the inorganic oxide constituting the inorganic oxide thin film layer include silicon oxide (SiOx), aluminum oxide, indium oxide, and the like.
Tin oxide, zirconium oxide, or the like can be used. Furthermore, in the present invention, the inorganic oxide may be a mixture of silicon monoxide and silicon dioxide, or a mixture of silicon oxide and aluminum oxide.

In the present invention, as a method of forming a thin layer of inorganic oxide, a vapor deposition method such as an ion beam method and an electron beam method, a sputtering method, a plasma chemical vapor deposition method (PCVD method) and the like are used. It can be formed by forming a film. In the above description, the thickness of the inorganic oxide thin film layer is usually preferably about 10 nm to 200 nm in order to obtain a sufficient barrier property, and particularly preferably about 20 to 150 nm in the present invention. . In the above, the thickness of the inorganic oxide thin film layer,
When it exceeds 150 nm, especially when it exceeds 200 nm,
It is not preferable because cracks and the like are easily formed in the thin film layer of the inorganic oxide, and there is a risk that the barrier property is deteriorated due to the warp, and the material cost is increased.

In the present invention, the innermost thermoplastic material layer is
At least 10 parts at least in the part to be sealed
It has a wide area sealing property that can be sealed at any temperature within the temperature range of 0 ° C to 80 ° C. An example of such an innermost thermoplastic material layer is a film of an ethylene-α-olefin copolymer polymerized using a metallocene catalyst. As this film, for example, a catalyst by a combination of a metallocene complex and an alumoxane such as a catalyst by a combination of zirconocene dichloride and methylalumoxane, that is, an ethylene-α-olefin copolymer obtained by polymerization using a metallocene catalyst Film or sheet can be used. The metallocene catalyst has a non-uniform active site and is called a multi-site catalyst, whereas the existing catalyst is called a single-site catalyst because the active site is uniform.

As a resin having a wide area sealing property, specifically,
The brand name "Cannel" manufactured by Mitsubishi Chemical Corporation, the brand name "Evolu" manufactured by Mitsui Petrochemical Industry Co., Ltd., the brand name "EXACT" manufactured by Exxon Chemical Co., USA, United States, Dow
Use of an ethylene-α-olefin copolymer film polymerized using a metallocene catalyst such as “AFFINITY” or “ENGAGE” manufactured by DOW CHEMICAL. Can be.

In the present invention, the above-mentioned ethylene-α-olefin copolymer film may be used in the form of a coating film or the like made of a composition containing the resin. The thickness of the film or film is 5μ
m to 300 μm, preferably 10 μm to 1
About 00 μm is desirable.

The single-site catalyst is characterized in that the polymerization active site is single (single-site), and the ethylene-α-olefin copolymer polymerized using this catalyst is different from the multi-site catalyst found in the conventional Ziegler catalyst. It has excellent properties that cannot be obtained with the ethylene-α-olefin copolymer obtained.

A typical single site catalyst is a metallocene catalyst, a so-called Kaminski catalyst.
The single-site catalyst is a metallocene-based transition metal compound and a catalyst comprising an organoaluminum compound.Examples of the metallocene-based transition metal compound include zirconium-based compounds, titanium-based compounds, and silica-based compounds. It is not limited to. Examples of the organoaluminum compound include alkylaluminum and a chain or cyclic aluminoxane, but the present invention is not limited thereto. Examples of the polymerization method include a solution polymerization method, a gas phase polymerization method, a slurry polymerization method, and the like, but none of them is particularly limited.

The α-olefin which is a comonomer copolymerized with ethylene includes butene-1, hexene-1, 4
-Methylpentene-1 and octene-1 are listed. These α-olefins may be used alone or as a mixture of two or more.

The mixing ratio of ethylene and α-olefin is 1 to
20% by weight is preferable, and the density of the polymerized ethylene-α-olefin copolymer is 0.900 to 0.915 g.
/ Cm3, more preferably 0.905 to / cm3.
0.910 g / cm3. If it is less than 0.900 g / cm3, the roll release property and the slip property of the film at the time of film formation become poor. Also, 0.915
If the density is higher than g / cm3, the flexibility and low-temperature sealing property of the film are inferior, and the sealing property is reduced. The molecular weight is 1.times.10@3 to 1.times.10@6, and the melt flow rate (MFR) is 3.0 to 30 g / 10 min, more preferably 10 to 20 g / 10 min. The peak melting point is 88 to 103 ° C, preferably 93 to 103 ° C.
° C. In addition, various antioxidants, ultraviolet absorbers, antistatic agents, lubricants, antiblocking agents, flame retardants, inorganic and inorganic fillers, dyes, pigments, etc. are appropriately added to the ethylene-α-olefin copolymer. May be. The low-density polyethylene only needs to be obtained using a conventional multi-site catalyst that is a Ziegler catalyst, and there is no particular limitation on the type of the catalyst or the polymerization method.

The density of the low-density polyethylene to be blended is 0.91 to 0.93 g / cm 3. The molecular weight is 1.times.10@2 to 1.times.10@8, and the melt flow rate (MFR) is 0.1 to 20 g / 10 min. In addition, basically no additive is used, but depending on the application, antioxidants, ultraviolet absorbers, antistatic agents, lubricants, antiblocking agents, flame retardants, inorganic and organic fillers, paints, Various additives such as a pigment may be appropriately added.

The packaging material for a paper container according to the present invention has an innermost layer at least at a temperature of 100 ° C.
It has a wide-range sealing property that can seal at any temperature within the temperature range of -80 ° C. As such an innermost thermoplastic material layer, as described above, there is an ethylene-α-olefin copolymer polymerized using a metallocene catalyst. In a preferred embodiment of the present invention, an ethylene-α-olefin copolymer polymerized using a single-site catalyst and a low-density polyethylene polymerized using a multi-site catalyst can be used. The layers other than the innermost layer of the paper container are not particularly limited.

The ethylene-α-olefin copolymer obtained by polymerization with a single-site catalyst has sealing properties such as sealing properties,
The proportion of the components necessary to maintain the impact resistance is 5
0 wt% or more, preferably 55 to 75 wt%, more preferably 55 to 65 wt%. If the amount is outside the above range, particularly if it is less than 50% by weight, good sealability and impact resistance cannot be obtained, and if it is 65% by weight, workability and lamination properties are undesirably reduced.

Next, the blending ratio of the low-density polyethylene obtained by polymerization with the multi-site catalyst required to increase the melt tension such as film formability is preferably 50% by weight or less, more preferably 45 to 25%. %, More preferably 45 to 35% by weight. Exceeding the above range is not desirable because good sealing properties and impact resistance cannot be obtained.

Any method can be adopted as a method for adjusting these resins. For example, after blending the respective components and mixing them with a blender, a mixer or the like, the mixture is melted with a twin-screw kneading extruder, a mixing roll, a Banbury mixer or the like. Any of a kneading method and a dry blending method of mixing pellets may be used. This embodiment is characterized by comprising an ethylene-α-olefin copolymer obtained by polymerization with a single-site catalyst and low-density polyethylene obtained by polymerization with a multi-site catalyst. Therefore, it is a polymer having a narrow molecular weight distribution (Mw / Mn ≦ 3) and a narrow composition distribution, which are characteristics of an ethylene-α-olefin copolymer polymerized with a single-site catalyst, and having a well-structured molecular structure. Maintains excellent characteristics of tensile strength, impact strength, tear strength, and low-temperature sealability, and has high entanglement of molecules due to high melt tension, which is one of the characteristics of low-density polyethylene polymerized with a multi-site catalyst. Become. Therefore, the film formability and the impurity sealing property can be improved. In addition, since the film formability is good, the concentration of additives such as a lubricant can be reduced, so that the obstacle to the sealability is reduced, the characteristics of the sealability can be maximized, and the content by the additive can be further improved. It has little effect on taste and ingredients and is excellent in sealability, so that an excellent paper container which does not impair the protection of contents can be obtained.

In the field of liquid food filling which embodies the present invention, a continuous paper packaging material is formed into a tube in the longitudinal direction, and a filling material such as fruit juice, tea, liquid dairy product or the like is filled in the tubular packaging material. A brick-shaped paper packaging container obtained by applying a horizontal line seal at predetermined intervals in the transverse direction of the tubular packaging material and cutting the packaging material along the horizontal line sealing portion, and a paper packaging material obtained by a predetermined method. A gable-top shape (roof type) obtained by cutting into a shape, obtaining a blank sealed in the vertical direction of the container, sealing the bottom of the blank, filling the filling of the liquid product from the upper opening, and sealing the upper portion Paper packaging containers.

The paper container of the present invention to be molded can be assembled into a processed paper container (one-piece type, two-piece type, three-piece type, etc.), a composite can, an insert-molded container, a double container, or the like. In this case, the packaging material is punched out according to a development view of the composite paper container, processed into a ruled line, and then folded along the ruled line and sealed to form various types of paper containers. At this time, as a sealing method, there are a heat seal, a frame seal, a hot air seal, an ultrasonic seal, a high frequency seal and the like. In addition, in a filling machine, these laminates are supplied in a roll shape, a sleeve shape or a cup shape, and after filling the contents,
A paper container is formed by being sealed using the various sealing methods described above.

Next, a method for producing a packaging material for a paper container according to the present invention will be described. Laminating ordinary packaging materials,
For example, wet lamination, dry lamination, solventless dry lamination, extrusion lamination, T-die coextrusion molding, coextrusion lamination, inflation, etc. be able to. In the present invention, when performing the above-mentioned lamination, if necessary, for example, corona treatment, pretreatment such as ozone treatment can be performed on the film, and, for example,
Isocyanate-based (urethane-based), polyethyleneimine-based, polybutadiene-based, organic titanium-based anchors
Polyurethane, polyacrylic, polyester, epoxy, polyvinyl acetate,
Known anchor coating agents, adhesives and the like, such as cellulose and other laminating adhesives, can be used.

In the manufacturing method of the packaging material, the extruded laminating
Examples of the extruded resin constituting the adhesive resin layer at the time of coating include polyethylene, ethylene-α-olefin copolymer, polypropylene, polybutene, polyisobutene, polyisobutylene, polybutadiene, polyisoprene, and ethylene-methacrylic acid copolymer. Or a copolymer of ethylene and an unsaturated carboxylic acid such as an ethylene-acrylic acid copolymer, or an acid-modified polyolefin resin obtained by modifying them, an ethylene-ethyl acrylate copolymer, an ionomer resin, an ethylene-acetic acid Vinyl copolymers and others can be used. Further, in the present invention, as the adhesive constituting the adhesive layer when dry laminating, specifically, a two-component curable urethane-based adhesive or a polyester urethane-based adhesive used in dry laminates and the like Polyether urethane adhesives, acrylic adhesives, polyester adhesives, polyamide adhesives, polyvinyl acetate adhesives, ethoxy adhesives, rubber adhesives, and the like can be used.

As shown in FIG. 1, the obtained packaging material is composed of an outermost thermoplastic material layer 21, a paper base layer 22, an adhesive thermoplastic material layer 23, a barrier layer 24, and an adhesive resin layer. 25,
The innermost thermoplastic material layer 26 is composed of the constituent layers. These wrapping materials are, for example, foldable wrapping materials.The wrapping material is formed into a tube shape by a longitudinal vertical line seal, and the material to be filled is placed in the tubing-shaped packaging material. Fill, apply a horizontal line seal in the transverse direction of the tubular packaging material, first form into a cushion-shaped or pillow-shaped primary shape, if the packaging material is strip-shaped, cut individually at regular intervals, along the fold line It is folded to form a brick (parallel hexahedron) final shape.

FIG. 2 shows an outline of an example of a filling and packaging machine used in the filling method according to the present invention. In the filling machine shown in this example, the packaging material web 1 having a thermoplastic material layer as the innermost layer is unwound and rolled, and the inside of the filling machine is conveyed by rollers, and the strip tape 2 is stripped by the strip tape applicator 3. The packaging material web is joined to one end of the packaging material web, sterilized by passing the packaging material web through the sterilizing agent tank 4, the sterilizing agent is removed by an air knife 5, and formed into a tube by a forming roller 6, and the tube is formed. The liquid food is filled from the filling pipe 7 and sealed in the vertical direction of the tube by the vertical sealing element 8, and the tube is fed downward by a length corresponding to one packaging container. Seal jaw 10 and opposing jaw 1
1 and heat-sealed in the transverse direction, and at the same time, continuously formed into the pillow-shaped filling and packaging container 12, and subsequently cut the cut portion of the sealing zone of the pillow-shaped packaging and filling container connected downstream thereof, The pillow-shaped container 14 is cut into the packaging and filling container 13 by a knife or the like, and the upper and lower flaps of the separated pillow-shaped container 14 are bent and formed into the final form of the packaging and filling container 11 by the final holder 14.

In the present invention, another example of manufacturing a paper container will be described. A blank plate for a paper container which has been processed to produce a paper container having a predetermined shape is punched, and then the edges of the blank plate are overlapped. A film of an ethylene-α-olefin copolymer polymerized using a metallocene catalyst as a heat-sealing film on the inner surface side of the polymerization end portion and a heat-sealing film on the outer surface side are welded. Then, a weld is formed to produce a sleeve. Next, the sleeve is mounted on a filling machine, and the bottom portion is folded along a predetermined ruled line and heat-sealed by hot-air treatment to form a bottom portion, and then the contents are filled from the opening at the top portion, Thereafter, the top portion is folded along a predetermined ruled line and heat-sealed by hot air treatment, for example, to form a top portion in the shape of a gabelle top, and to manufacture a packed and packed product. Can be. The above-mentioned examples are merely examples of the packaging container according to the present invention, and the present invention is not limited thereto.

The packaging container according to the present invention includes, for example, milk, lactic acid bacteria drink, liquid soup, fruit juice drink, barley tea, green tea,
Liquid products such as Woolong tea, alcoholic beverages, seasonings, pharmaceuticals, cosmetics, paints, adhesives, inks, developers, etching solutions, etc. can be applied to filling and packaging,
Preferably, it is a liquid food.

[0044]

EXAMPLES The present invention will be specifically described with reference to the following examples. <Example 1> Low density polyethylene (density = 0.920 g)
/ Cm @ 3, MI = 5.1) at a extrusion temperature of 330 DEG C. on a paper substrate (basis weight = 320 g / m @ 2) at a thickness of 20 .mu.m. Next, an ethylene-octene-1 copolymer (density = 0.912 g / cm 3, MI = 15) polymerized with a single-site catalyst was applied to the surface of the 9 μm-thick aluminum foil coated with the ionomer (Surlyn) at 60 wt. % And low-density polyethylene (density = 0.923 g / cm 3, MI = 3.7) polymerized with a multi-site catalyst.
0% by weight with a dry blending method, and an extrusion temperature of 22%.
At 0 ° C., a film molded to a thickness of 60 μm was corona-treated and bonded to form a laminated film composed of an aluminum foil / blended resin. Further, the paper side of the low-density polyethylene / paper base and the aluminum foil side of the aluminum foil laminate were sand-laminated via low-density polyethylene (thickness: 20 μm) to prepare a laminate sheet for a gobel top type. . Then, using this laminated sheet for goebel top type, punching and skiving hemming were performed to create a sleeve, and a liquid-filled molding machine was used to produce a 1-liter gobel top type container.

Example 2 In Example 1, an ethylene-hexene-1 copolymer (density = 0.910 g / cm 3, polymerized with a single-site catalyst using an ethylene-vinyl acetate copolymer instead of Surlyn) MI = 12) is 5
A 1 liter göbel top type paper container is prepared in the same manner as in Example 1, except that a blend resin composed of 5% by weight and 45% by weight of a low-density polyethylene polymerized with a multisite catalyst is used.

<Embodiment 3> Using the same packaging material as in Embodiments 1 and 2, a paper container having a brick shape is produced by a filling machine shown in FIG.

The drop test was evaluated, and these containers were dropped at a normal temperature with the bottom face down from a height of 1 m, and the drop was repeated up to 10 times until the bag was broken. The containers according to the examples do not leak even after 10 drop tests and have excellent impact resistance.

The contaminant sealability of the innermost layer film is tested to evaluate the film formability. As a result, while having excellent impact resistance, excellent film formability, and
Excellent sealability for impurities. Further, those using an ethylene-α-olefin copolymer polymerized using a metallocene catalyst are about 50% less than those not using it.
Heat sealing is possible at a low temperature.

[0049]

According to the present invention demonstrated in the above embodiment, the following effects can be obtained. Since the paper container of the present invention has the above-described structure, it retains the characteristics of an ethylene-α-olefin copolymer polymerized with a single-site catalyst, which are excellent in tensile strength, impact resistance, tear strength, and low-temperature sealability. And, because of the high melt tension characteristic of low-density polyethylene polymerized with a multi-site catalyst, the entanglement of the molecule is increased, the film moldability and the foreign matter sealing property are improved, and the sealing property is excellent. Become.

Further, since the film formability is good, the concentration of additives such as a lubricant can be reduced, the obstacle to the sealing property is reduced, and the excellent sealing property can be obtained to the maximum. Further, the effect of the additive on the taste and components of the content is small and the sealing property is excellent, so that the content protection property is also excellent.

At the time of box making, a low-temperature heat seal becomes possible, and a good seal can be obtained at high or low temperature without being affected by the temperature of the filling contents. Since the temperature can be set to a lower temperature than when using them as usual, heat damage can be reduced even if a thin film layer of an inorganic oxide or a thin film of aluminum is used for the barrier layer, As a result, barrier deterioration and the like can be suppressed.

[Brief description of the drawings]

FIG. 1 is a schematic sectional view showing a layer structure of an embodiment of a packaging material for a paper container of the present invention.

FIG. 2 is a schematic diagram of a filling machine that can be used to carry out the filling method of the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Packaging material web 10 Seal jaw 11 Opposing jaw 21 Outermost thermoplastic material layer 22 Paper base material layer 23 Adhesive thermoplastic material layer 24 Barrier layer 25 Adhesive resin layer 26 Innermost thermoplastic material layer

 ──────────────────────────────────────────────────続 き Continuing from the front page (72) Inventor Hiroaki Ogita F-term (Reference) 3E060 BC01 BC04 DA20 EA03 in 6-12 Kioicho, Chiyoda-ku, Tokyo Japan

Claims (2)

[Claims] At least each of constituent layers of an outermost thermoplastic material layer, a paper base material layer, an adhesive thermoplastic material layer, a barrier layer, and an innermost thermoplastic material layer, and these layers are laminated in the above order. A packaging material for a paper container, which is obtained by sealing the innermost thermoplastic material layer at least in a temperature range of 100 ° C. to 80 ° C. at least in a portion to be sealed. A packaging material for a paper container, wherein the barrier layer and the innermost thermoplastic material layer are joined by an adhesive resin layer selected from an ethylene-vinyl acetate copolymer and an ionomer. 2. A packaging material including a continuous paper base layer provided with a fold line is vertically sealed by overlapping an innermost layer at one end and an outermost layer at the other end of the packaging material. Formed into a tube in the longitudinal direction, filling the liquid food to be filled in the tube-shaped packaging material, joining the innermost layers of the tubular packaging material to each other below the liquid level of the liquid food, and crosswise. This is a filling and packaging method in which a horizontal line seal is applied at predetermined intervals, the packaging material is cut along the horizontal line seal portion, formed into a primary shape, folded along a fold line and formed into a final shape to obtain a packaging container. The innermost layer of the wrapping material corresponding to at least the horizontal line seal portion and / or the vertical seal portion is made of a thermoplastic material having a wide-range sealing property that can seal at any temperature within a temperature range of at least 100 ° C to 80 ° C. A liquid food filling and packaging method characterized by the above-mentioned.