JP2006027696A - Tubular paper container - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a tubular paper container highly practical as a paper container for a high functional liquid body, which container is free from crack or delamination, etc. even when a stress such as a tension or a shock is applied to the four corners of the container in processing the container, is provided with a long lasting gas barrier characteristic even when a content is stored for a long time, is excellent in rigidity and drop strength and is easily disposed of after use. <P>SOLUTION: A laminate is used as a material of a lid body 2, a bottom body 3 and a body part 1 constituting the container, and the laminate comprises a paper layer having a heat-seal layer on the surface thereof as a substrate. At least a vapor deposition film comprising an inorganic oxide is disposed as a gas barrier material inside the substrate, and a heat seal layer is provided inside of the gas barrier material. The tubular paper container comprises the body part 1 made by applying an edge protecting work to the laminate and forming the laminate into a tube and the lid bod 2 and the bottom body. The four corners of the container are rounded to a radius of 10 mm. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  TECHNICAL FIELD The present invention relates to a cylindrical paper container mainly composed of a paper layer containing beverages, alcohols, etc., and more specifically, a container comprising a trunk, a lid and a bottom including a transparent gas barrier material. Even when stress such as pulling or impact is applied to the container square in the processing process, cracking and delamination can be prevented, and the gas barrier property can be maintained even if the contents are stored for a long time It relates to the cylindrical paper container which has.

  A paper container using a paper laminate material mainly composed of a paper layer and provided with a heat-sealable resin layer as an innermost layer and an outermost layer is used as a container replacing a can or a bottle. In order to improve the storage stability of the contents of these paper containers, a configuration in which a gas barrier material is arranged in the laminated configuration is adopted. A typical material for the gas barrier material is aluminum foil. However, when an aluminum foil is included in the laminated structure, there is a problem that separation processing after use becomes difficult and incineration processing cannot be performed as it is. As a gas barrier material replacing the aluminum foil, a transparent gas barrier material made of a vapor deposition film provided with an inorganic compound vapor deposition layer such as silicon oxide or aluminum oxide has come to be used.

  However, a paper container having a configuration in which a transparent gas barrier material composed of a vapor deposition film provided with an inorganic compound vapor deposition layer such as silicon oxide or aluminum oxide as described above is disposed in the container processing step, particularly, the container shape is a square pillar. In such a case, there has been a problem that the gas barrier property is lowered due to stress such as pulling or impact being applied to the container square, causing cracks in the vapor deposition layer or delamination. A paper container having a configuration in which a transparent gas barrier material made of a conventional deposited film is disposed has insufficient gas barrier properties as a paper container for storing contents for a long period of time. Therefore, it has been desired to develop a highly functional liquid paper container having high gas barrier properties that can maintain gas barrier properties even if the contents are stored for a long period of time, and excellent in strength.

  Since the present invention is made in consideration of the above technical background, cracks, delamination, etc. occur even when stress such as tension or impact is applied to the container square in the container processing process. High-performance liquid paper container that has high gas barrier properties that can maintain gas barrier properties even when stored for a long period of time, has excellent rigidity and drop strength as a container, and is easy to dispose of after use An object of the present invention is to provide a highly practical cylindrical paper container.

To achieve the above objectives, ie
The invention according to claim 1
As a material for the body, lid and bottom constituting the container, a paper layer having a heat-sealable resin layer on the surface is used as a base material, and vapor deposition comprising at least an inorganic oxide as a gas barrier material inside the base material. Using a laminated material in which a film is placed and a heat-sealable resin layer is provided on the inside of the gas barrier material, it is composed of a body part that is edge-protected and molded into a cylindrical shape, and a lid and bottom body. The cylindrical paper container is characterized by having a square R dimension of 10 mm or more.

The invention according to claim 2
As a material for the body, lid and bottom constituting the container, a paper layer having a heat-sealable resin layer on the surface is used as a base material, and a thermoplastic resin layer and a gas barrier material are used as intermediate layers inside the base material. 2. The cylindrical paper container according to claim 1, wherein the laminated paper material is a laminated material in which vapor-deposited films made of inorganic oxide are arranged in this order and a heat-sealable resin layer is provided inside the gas barrier material.

The invention according to claim 3
The cylindrical paper container according to claim 1 or 2, wherein the inorganic oxide is aluminum oxide, silicon oxide, tin oxide, magnesium oxide, or a mixture thereof.

The invention according to claim 4
The cylindrical paper container according to any one of claims 1 to 3, wherein a water gas gas barrier coating layer is formed on the vapor deposition surface of the vapor deposition film made of an inorganic oxide of the gas barrier material.

The invention according to claim 5
The water gas barrier coating layer is mainly composed of a water-soluble polymer, (a) one or more metal alkoxides and hydrolysates thereof, or (b) an aqueous solution containing at least one of tin chloride, or a water / alcohol mixed solution. The cylindrical paper container according to claim 4, wherein the coating agent is applied and dried by heating.

<Action>
Using a transparent gas barrier material made of a vapor deposition film provided with a vapor deposition layer made of an inorganic oxide on the inside of a base material used for the body, lid, and bottom body constituting the cylindrical paper container of the present invention, and A structure in which a water gas barrier coating layer can be provided on a vapor-deposited layer made of an inorganic oxide, and by making the square R dimension of the container 10 mm or more, generation of cracks and delamination in the processing process of the container is prevented. Even when the contents are stored for a long period of time, high gas barrier properties against oxygen gas and the like can be maintained. Further, the drop strength is improved together with the rigidity when the cylindrical paper container is used.

  Since the cylindrical paper container of the present invention is configured as described above, it prevents the occurrence of cracks and delamination in the processing process of the container, and maintains high gas barrier properties even when the contents are stored for a long period of time. A highly practical cylindrical paper container as a highly functional liquid paper container can be provided. Further, the container has excellent rigidity and drop strength, and can be used as a container having a certain rigidity and drop strength, such as a vending machine.

  Furthermore, in order to improve the storage stability of the contents of conventional paper containers, problems such as separation processing and incineration processing after use of conventional paper containers with a configuration in which a gas barrier material made of aluminum foil is arranged in the laminated structure are solved. The

  Hereinafter, an embodiment as an example of the present invention will be described in detail with reference to the drawings.

  FIG. 1 is an explanatory view illustrating an example of a cylindrical paper container of the present invention. FIG. 2 is a cross-sectional view showing an example of the configuration of a laminated material used for the body, lid, and bottom of the cylindrical paper container of the present invention. FIG. 3 is a cross-sectional view showing another example of the configuration of the laminated material used for the body, lid, and bottom of the cylindrical paper container of the present invention. FIG. 4 is a cross-sectional view showing an example of the configuration of an edge protection tape used in edge protection processing in the body portion of the cylindrical paper container of the present invention. FIG. 5 is a top view and a side view showing dimensions as one embodiment of the cylindrical paper container of the present invention. FIG. 6 is an explanatory view for explaining edge protection processing in the body portion of the cylindrical paper container of the present invention.

  In FIG. 1, a cylindrical paper container as an embodiment of the present invention is characterized by having a square R dimension of 10 mm or more. The lid body 2 and the bottom body 3 are arranged above and below the body portion, and the folded portions obtained by folding back the edges of the lid body 2 and the bottom body 3 are folded at both ends of the body portion 1 to overlap each other. A container integrated by a seal. Here, the lid 2 is provided with a drinking mouth 4 at a portion, and the drinking mouth 4 is covered and sealed with a sealing material 5.

  The cylindrical paper container of the present invention refers to a quadrangular prism with a rounded square shape or a cylindrical shape.

  In FIG. 2, as an example of the laminated material used for the trunk, lid, and bottom of the cylindrical paper container in the present invention, 10 and 16 are heat-sealable resin layers, 11 is a paper layer, and 12 is an intermediate layer. A thermoplastic film base material such as polyethylene (PE), 13 is a film base material on which vapor deposition is performed, 15 is a transparent gas barrier material comprising a vapor deposition film formed by forming a vapor deposition layer 14 made of an inorganic oxide on the film base material 13. It is. And it arrange | positions so that it may become the container outer side when the upper side of a figure makes a container and the lower side of a figure makes a container.

  In FIG. 3, as another example of the laminated material used for the body, lid, and bottom of the cylindrical paper container in the present invention, 10 and 16 are heat-sealable resin layers, 11 is a paper layer, and 12 Is a thermoplastic film substrate such as polyethylene (PE) as an intermediate layer, 13 is a film substrate on which vapor deposition is performed, 15 is a vapor deposited layer 14 made of an inorganic oxide on the film substrate 13, and this inorganic oxide Or a water / alcohol mixed solution containing at least one of a water-soluble polymer, (a) one or more metal alkoxides and hydrolysates thereof, or (b) tin chloride. The example of the laminated material which comprises the cylindrical paper container of this invention of the structure which provided the aqueous | water-based gas barrier coating layer 17 which apply | coats the coating agent which makes a main ingredient, and heat-drys is shown. And it arrange | positions so that it may become the container outer side when the upper side of a figure makes a container and the lower side of a figure makes a container.

  As shown in FIG. 7 (a), the barrel 1 of the cylindrical paper container of the present invention is formed into a cylindrical shape by applying edge protection to the end surface portion 6 of the barrel laminate material that becomes the inner surface of the vessel. As an example of the edge protection tape used for this edge protection processing, in FIG. 4, 10 and 16 are heat-sealable resin layers, 13 is a film substrate on which vapor deposition is performed, and 15 is an inorganic oxide on the film substrate 13. It is an edge protection tape formed by forming a vapor deposition layer 14 made of

  Using the edge protection tape having the above structure, as shown in FIG. 7B, the edge protection tape 7 is laminated so as to cover the end surface 1b in contact with the contents of the laminated material 1a used for the container body 1. Provide.

  A top view and a side view showing dimensions as one embodiment of the cylindrical paper container of the present invention using the laminated material constituting the trunk, lid, and bottom, as shown in FIG. Body 1 molded into a cylinder with protection, side surface of this body is 54 mm, height is 108 mm, container square R dimension is 10 mm or more, and lid 2 and bottom 3 are placed above and below the container Then, the folded portion of the lid body 2 and the bottom body 3 with the width of 7 mm folded is overlapped by folding both ends of the body portion 1 and integrated by heat sealing. Here, the lid 2 is provided with a drinking mouth 4 at a portion, and the drinking mouth 4 is covered and sealed with a sealing material 5.

The thermoplastic film substrate 12 as an intermediate layer and the film substrate 13 for vapor deposition used in the present invention are in the form of a film, and plastic films that are usually used as packaging materials can be used. Although not particularly limited, a polyethylene terephthalate film (PET), a polyethylene terephthalate copolymer polyester film, a polyester film such as a polyethylene naphthalate film, a nylon 66 film,
Polyamide film such as nylon 6 film, metaxylidenediamine copolymerized polyamide film, polycarbonate film, polypropylene film, polyethylene film (PE), ethylene-propylene copolymer film, polyimide film, polyamideimide film, polyvinyl alcohol Examples thereof include a film, an ethylene-vinyl alcohol copolymer film, a polyphenylene film, a polysulfone film, and a polyphenylene sulfide film. Of these, polyester films and polyamide films can be more preferably used from the viewpoints of heat resistance, strength, suitability for vapor deposition, and the like. The thickness of these films is not particularly limited, but is preferably about 6 μm to 300 μm, and more preferably 6 to 25 μm from the viewpoint of flexibility. These plastic films may be used alone or may be used by being laminated.

  For example, known additives such as an antistatic agent, an ultraviolet absorber, a plasticizer, a lubricant, and a colorant are appropriately added to the film bases 12 and 13 as necessary.

  Further, if necessary, the surface of the film base 13 on which the vapor deposition is performed may be subjected to, for example, corona discharge treatment, ozone treatment, low temperature plasma treatment using oxygen gas or nitrogen gas, glow discharge treatment, chemical treatment. A pretreatment such as an oxidation treatment using a chemical or the like, or the like can be optionally performed. The surface pretreatment may be performed in a separate process before forming the vapor deposition layer. For example, in the case of surface treatment by low-temperature plasma treatment, glow discharge treatment, etc., as the pretreatment for forming the vapor deposition layer Preprocessing can be performed by inline processing. In such a case, there is an advantage that the manufacturing cost can be reduced. As other methods for improving the above-mentioned adhesion, for example, a primer coat agent layer, an undercoat agent layer, or a deposition anchor coat agent layer is previously formed on the surface of the film substrate. It can also be arbitrarily formed. As the pre-treatment coating agent layer, for example, a resin composition containing a polyester resin, a polyurethane resin, or the like as a main component of the vehicle can be used. In the above, the coating agent layer can be formed by using, for example, a solvent type, aqueous type, or emulsion type coating agent, a roll coating method, a gravure roll coating, etc. The coating can be performed using a coating method such as a method, a kiss coating method, or the like. Surface adhesion such as corona treatment and anchor coating treatment can be performed to improve the adhesion of the deposited layer.

  The vapor deposition layer 14 made of an inorganic oxide in the present invention is made of an oxide such as silicon, aluminum, titanium, zirconium, tin, magnesium, nitride, fluoride alone, or a composite thereof. Aluminum oxide and silicon oxide are preferred.

  Moreover, the thickness of the vapor deposition layer 14 which consists of inorganic oxides has the preferable range of 5-300 nm. The optimum thickness of the thin film layer varies depending on the type and configuration of the inorganic compound used, but the value is appropriately selected. If the film thickness is less than 5 nm, a uniform film may not be obtained or the film thickness may not be sufficient, and the function as a gas gas barrier material may not be sufficiently achieved. When the film thickness exceeds 300 nm, flexibility cannot be maintained in the thin film, and it is particularly preferably in the range of 10 to 150 nm.

  There are various methods for forming the vapor deposition layer 14 made of the above inorganic oxide, and it can be formed by a normal vacuum vapor deposition method. However, other thin film formation methods such as sputtering, ion plating, A phase growth method (CVD) or the like can also be used. However, considering productivity, the vacuum deposition method is the best at present. As the heating means of the vacuum deposition apparatus by the vacuum deposition method, an electron beam heating method, a resistance heating method, or an induction heating method is preferable. In order to improve the adhesion between the thin film and the base material and the denseness of the thin film, a plasma assist method or an ion It is also possible to use a beam assist method. In addition, in order to increase the transparency of the deposited film, reactive deposition such as blowing oxygen gas may be performed during the deposition.

  Moreover, it is set as the structure which provided the water gas barrier coating layer 17 on the vapor deposition layer 14 of the vapor deposition film 15 shown in FIG. 3 as a laminated material used for the trunk | drum of the cylindrical paper container of this invention, a cover body, and a bottom body. Further, the gas barrier property can be improved. The water gas barrier coating layer 17 is mainly composed of an aqueous solution containing at least one of a water-soluble polymer and (a) one or more metal alkoxides and hydrolysates thereof, or (b) tin chloride, or a water / alcohol mixed solution. It consists of a coating agent. A solution in which a water-soluble polymer and tin chloride are dissolved in an aqueous (water or water / alcohol mixed) solvent, or a solution in which a metal alkoxide is directly or previously hydrolyzed is mixed. The vapor deposition layer 14 made of an inorganic oxide of the vapor deposition film 16 is formed by coating, heating and drying.

  Examples of the coating agent for the water gas barrier coating layer 17 in the present invention include polyvinyl alcohol, polyvinyl pyrrolidone, starch, methyl cellulose, carboxymethyl cellulose, sodium alginate and the like. In particular, when polyvinyl alcohol (PVA) is used for the coating agent of the gas barrier laminate of the present invention, the gas barrier property is most excellent. PVA here is generally obtained by saponifying polyvinyl acetate, from so-called partially saponified PVA in which several tens percent of acetic acid groups remain to completely saponified PVA in which only several percent of acetic acid groups remain. There is no particular limitation.

The tin chloride may be stannous chloride (SnCl ₂ ), stannic chloride (SnCl ₄ ), or a mixture thereof, and may be used as an anhydride or a hydrate.

Furthermore, the metal alkoxide has a general formula such as tetraethoxysilane [Si (OC ₂ H ₅ ) ₄ ], triisopropoxy aluminum [Al (O-2′-C ₃ H ₇ ) ₃ ],
M (OR) _n
(M: metal such as Si, Ti, Ai and Zr, R: alkyl group such as CH ₃ and C ₂ H ₅ ). Among these, tetraethoxysilane and triisopropoxyaluminum are preferable because they are relatively stable in an aqueous solvent after hydrolysis.

  Each of the above-mentioned components can be added to the coating agent alone or in combination, and an isocyanate compound, a silane coupling agent, or a dispersant, a stabilizer, and a viscosity adjustment as long as the gas barrier property of the coating agent is not impaired. Known additives such as coloring agents and coloring agents can be added.

  For example, the isocyanate compound added to the coating agent has two or more isocyanate groups (NCO groups) in the molecule, such as tolylene diisocyanate (TDI), triphenylmethane triisocyanate (TTI), tetramethyl. There are monomers such as xylene diisocyanate (TMXDI), and polymers and derivatives thereof.

  Conventionally known means such as a dipping method, a roll coating method, a screen printing method, and a spray method are used for the coating method of the coating agent. The thickness of the film varies depending on the type of the coating agent, but the thickness after drying may be in the range of about 0.01 to 100 μm. 50 μm is desirable.

Next, the heat seal resin constituting the heat seal resin layers 10 and 16 used in the present invention is a thermoplastic resin that can be extruded and can be melted by heat and fused to each other. For example, low density polyethylene, medium density polyethylene, high density polyethylene, linear (linear) low density polyethylene, polypropylene, ethylene-vinyl acetate copolymer, ionomer resin, ethylene-ethyl acrylate copolymer Polyolefin resins such as ethylene-acrylic acid copolymer, ethylene-methacrylic acid copolymer, ethylene-propylene copolymer, methylpentene polymer, polyethylene or polypropylene, acrylic acid, methacrylic acid, maleic acid, maleic anhydride , Unsaturated carboxylic acids such as fumaric acid, itaconic acid, etc. Sex was acid-modified polyolefin resins, polyvinyl acetate resins, polyester resins, polystyrene resins, one or resin comprising more resins other like can be used.

Among the above resins, it is particularly preferable to use linear (linear) low density polyethylene. The above-mentioned linear low density polyethylene has the advantage of improving impact resistance with less propagation of breakage because it has adhesiveness, and since the inner layer is always in contact with the contents, It is also effective for preventing deterioration of environmental stress cracking properties. As a method for laminating the laminated material used for the body 1, the lid 2 and the bottom 3 of the cylindrical paper container of the present invention, for example, laminating It is possible to carry out by a dry lamination method in which lamination is performed through a laminating adhesive layer using a glue adhesive, or an extrusion lamination method in which lamination is performed through a melt extrusion resin layer using a melt extrusion adhesive resin. . In the above, as the laminating adhesive, for example, one-pack or two-pack curable or non-cured vinyl, (meth) acrylic, polyamide, polyester, polyether, polyurethane, etc. Laminate adhesives such as solvent-type, epoxy-type, rubber-type, and other solvent-type, aqueous-type, and emulsion-type can be used. Examples of the coating method for the above laminating adhesive include direct gravure roll coating method, gravure roll coating method, kiss coating method, reverse roll coating method, and Fonten method. , Transfer roll coating method, etc., and the coating amount is 0.1 to 10 g / m ² (dry state), more preferably 1 to 5 g. / M ² (dry state) is desirable.

  In the present invention, for example, an adhesion promoter such as a silane coupling agent can be arbitrarily added to the laminating adhesive. Next, in the above, as the melt-extrusion adhesive resin, the thermoplastic resin that forms the above-described thermoplastic resin layer can be similarly used. In the present invention, as the melt-extrusion adhesive resin, it is particularly preferable to use low-density polyethylene, particularly linear low-density polyethylene or acid-modified polyethylene. The film thickness of the melt-extruded resin layer made of the above-described melt-extruded adhesive resin is preferably about 5 to 100 μm, more preferably about 10 to 50 μm.

In the present invention, when it is necessary to obtain a stronger adhesive strength when performing the above-described lamination, if necessary, for example, an adhesion improving agent such as an anchor coating agent may be coated. You can also Specific examples of the anchor coat agent include organic titanium anchor coat agents such as alkyl titanate, isocyanate anchor coat agents, and polyethyleneimine anchor coats. -Various anchor coating agents such as water-based or oil-based coating agents such as a coating agent, a polybutadiene anchor coating agent, and the like can be used. In the present invention, the above-mentioned anchor coating agent is coated by, for example, a roll coat, a gravure coat, a knife coat, a dip coat, a spray coat, or other coating methods. Then, the solvent, diluent, etc. can be dried to form the anchor coating layer. In the above, the coating amount of the anchor coating agent is preferably about 0.1 to 5 g / m ² (dry state).

In addition, a printing layer is usually provided on the surface of the paper layer that forms the outer side of the cylindrical paper container of the present invention. This printed layer is formed for practical use as a package such as a container. For example, various types of pigments, extender pigments, plasticizers, drying agents, stabilizers and other additives are added to conventionally used ink binder resins such as urethanes, acrylics, nitrocelluloses, and rubbers. It is a layer composed of ink. Characters, pictures, and the like are formed by this printing. As a forming method, for example, a known printing method such as an offset printing method, a gravure printing method, a silk screen printing method, or a known coating method such as a roll coating, a knife edge coating, or a gravure coating can be used. The dry film thickness (solid content) of the printing layer may be 0.1 to 2.0 μm.

  Among the above, it is preferable to employ a gravure printing method using an ink that complies with the self-regulatory standards for food packaging material inks.

  Examples of the present invention will be specifically described below.

  First, each laminated material was produced about the trunk | drum which comprised the cylindrical paper container of this invention, a cover body, a bottom body, and the edge protection tape used for edge protection processing.

<Body laminate material>
Outside: heat seal resin layer (PE; 20 μm) / paper layer (paper; basis weight 300 g / m ² ) / intermediate layer (PE; 30 μm) / (aluminum oxide / PET; 12 μm) vapor deposited film layer (total thickness 15 μm) / Heat-sealing resin layer (PE; 60 μm): A body laminate material having an inner structure was prepared.

<Cover Laminate Material>
Outside: heat seal resin layer (PE; 40 μm) / paper layer (paper; basis weight 250 g / m ² ) / intermediate layer (PE; 30 μm) / (aluminum oxide / PET; 12 μm) vapor deposited film layer (total thickness 15 μm) / Heat-sealing resin layer (PE; 60 μm): A body laminate material having an inner structure was prepared.

<Bottom laminate material>
Outside: heat seal resin layer (PE; 40 μm) / paper layer (paper; basis weight 200 g / m ² ) / intermediate layer (PE; 20 μm) / (aluminum oxide / PET; 12 μm) vapor deposited film layer (total thickness 15 μm) / Heat-sealing resin layer (PE; 60 μm): A body laminate material having an inner structure was prepared.

<Edge protection tape laminate material>
Heat seal resin layer (PE; 40 μm) / (aluminum oxide / PET; 12 μm) vapor deposition film layer (total thickness 15 μm) / heat seal resin layer (PE; 40 μm)
A body part formed of the above laminated material in a cylindrical shape by applying edge protection processing, a lid body and a bottom body are arranged above and below the body part, and a folded part in which the edge of the lid body and the bottom body is folded back The cylindrical paper container of the present invention having a capacity of 250 cc and a container square R dimension of 20 mm was prepared by bending both ends of the body part and overlapping and integrating them by heat sealing.

  In Example 1, the cylindrical paper container of this invention was created like Example 1 except having changed the R dimension of the container square into 16 mm.

  In Example 1, the cylindrical paper container of this invention was created like Example 1 except having changed the R dimension of the container square into 14 mm.

  In Example 1, the cylindrical paper container of this invention was created like Example 1 except having changed the R dimension of the container square into 10 mm.

  In order to compare the performance with the cylindrical paper container of the present invention, a cylindrical paper container as a comparative example was prepared in the same manner as in Example 1 except that the R dimension of the container square was changed to 8 mm. .

  The oxygen permeability of the cylindrical paper containers obtained in Examples 1 to 5 was evaluated based on the following measurement method. The results are shown in Table 1.

<Oxygen permeability measurement method>
Using an oxygen permeability measuring device (Modern Control, OXTRAN-2 / 20), measurement was performed in an atmosphere at 25 ° C.-70% RH.

表１には、各実施例で得られた筒状紙容器の容器四角のＲ寸法および酸素透過度を記してある。

Table 1 shows the R dimension and oxygen permeability of the container square of the cylindrical paper container obtained in each example.

  From Table 1, in Example 5 as a comparative example for comparing the oxygen permeability of the cylindrical paper container of the present invention obtained in Examples 1 to 4 with the oxygen permeability of the cylindrical paper container of the present invention. When the oxygen permeability of the obtained cylindrical paper container is compared, the oxygen permeability of the cylindrical paper container of the present invention is 0.005 to 0.009 cc / pack · day · 0.02 MPa. On the other hand, the oxygen permeability of a cylindrical paper container having a square R dimension of 8 mm as a comparative example is 0.035 to 0.076 cc / pack · day · 0.02 MPa, and the cylindrical paper container of the present invention is Excellent oxygen gas barrier properties. Further, the cylindrical paper container as a comparative example has a problem in terms of moldability. This is because a cylindrical paper container that does not satisfy the condition that the square R dimension of the container is 10 mm or more is subjected to stress such as tension or impact in the processing process of the container, and cracks, delamination, etc. are generated. It is thought that the nature decreases. In contrast, the cylindrical paper container of the present invention has a square R dimension of 10 mm or more, so that the stress applied to the container square can be relaxed and the occurrence of cracks, delamination, etc. can be prevented, and excellent oxygen gas gas barrier properties It is thought that it expresses. Therefore, the cylindrical paper container of the present invention has a high gas barrier property that can maintain the gas barrier property even if the contents are stored for a long period of time, has excellent rigidity and drop strength as a container, and is easy to dispose of after use. It is possible to provide a highly practical cylindrical paper container as a highly functional liquid paper container.

It is explanatory drawing which shows an example of the cylindrical paper container of this invention. (A) is a perspective view of a cylindrical paper container. (B) is the enlarged top view which expanded and showed the cover body part of the upper surface of the cylindrical paper container shown to (a). It is sectional drawing which shows an example of a structure of the laminated material used for the trunk | drum, the cover body, and the bottom body of the cylindrical paper container of this invention. It is sectional drawing which shows the other example of a structure of the laminated material used for the trunk | drum, the cover body, and the bottom body of the cylindrical paper container of this invention. It is sectional drawing which shows an example of a structure of the edge protection tape used for the edge protection process in the cylindrical paper container of this invention. It is the top view (a) and side view (b) which show the dimension as one Example of the cylindrical paper container of this invention. It is explanatory drawing explaining the edge protection process in the cylindrical paper container of this invention. (A) is a perspective view shown to the container which performed edge protection processing. (B) is an enlarged longitudinal sectional view showing an edge protection processing portion.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Body part 1a ... Body part laminated material 1b ... Body part laminated material end surface 2 ... Cover body 3 ... Bottom body 4 ... Drinking mouth 5 ... Sealing material 6 .... Edge protection processing part 7 ... Edge protection tape 10, 16 ... Heat seal resin layer 11 ... Paper layer 12 ... Intermediate layer 13 ... Film base material layer 14 to be deposited ... Deposition layer 15 made of inorganic oxide ... Deposition film 17 ... Water gas barrier coating layer

Claims (5)

  As a material for the body, lid and bottom constituting the container, a paper layer having a heat-sealable resin layer on the surface is used as a base material, and vapor deposition comprising at least an inorganic oxide as a gas barrier material inside the base material. Using a laminated material in which a film is placed and a heat-sealable resin layer is provided on the inside of the gas barrier material, it is composed of a body part that is edge-protected and molded into a cylindrical shape, and a lid and bottom body. A cylindrical paper container having a square R dimension of 10 mm or more.   As a material for the body, lid and bottom constituting the container, a paper layer having a heat-sealable resin layer on the surface is used as a base material, and a thermoplastic resin layer and a gas barrier material are used as intermediate layers inside the base material. The cylindrical paper container according to claim 1, wherein the laminated paper material is a laminated material in which vapor-deposited films made of an inorganic oxide are arranged in this order and a heat-sealable resin layer is provided inside the gas barrier material.   The cylindrical paper container according to claim 1 or 2, wherein the inorganic oxide is aluminum oxide, silicon oxide, tin oxide, magnesium oxide, or a mixture thereof.   The cylindrical paper container according to any one of claims 1 to 3, wherein a water gas barrier coating layer is formed on a vapor deposition surface of a vapor deposition film made of an inorganic oxide of the gas barrier material.   The water gas barrier coating layer is mainly composed of a water-soluble polymer, (a) one or more metal alkoxides and hydrolysates thereof, or (b) an aqueous solution containing at least one of tin chloride, or a water / alcohol mixed solution. The cylindrical paper container according to claim 4, wherein the coating agent is applied and dried by heating.

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