JP5223176B2 - Liquid paper container and manufacturing method thereof - Google Patents

Description

  The present invention relates to a liquid paper container and a method for manufacturing the same, and more particularly to a liquid paper container and a method for manufacturing the same that prevent the occurrence of pinholes.

In general, a liquid paper container is formed by using packaging materials composed of various laminates in order to ensure the storage stability of the contents, the strength as the container, the gas barrier property, and the like. And as a packaging material used for such a liquid paper container, an inner surface layer containing an adhesive polyolefin resin, a barrier layer containing a polyamide resin located outside the inner surface layer, and a paper-based support A packaging material having an olefin-based resin layer on both sides of a body and a base material layer positioned outside the barrier layer is known (for example, see Patent Document 1).
JP 4-179543

  When assembling and bonding the packaging material for the liquid paper container described above, usually, hot air (hot air) is blown to the bonding position to melt and bond the adhesive polyolefin resin. At that time, there is a possibility that pinholes occur in the constituent material of the liquid paper container (the above-mentioned adhesive polyolefin resin). When a pinhole is generated by heating in the packaging material of the liquid paper container, the barrier function is lowered, and the contents may leak.

  Accordingly, an object of the present invention is to provide a liquid paper container having a high barrier property and a method for manufacturing the same, by preventing the occurrence of pinholes due to heating.

  In order to achieve the above object, the liquid paper container of the present invention comprises, from the outer surface side, an outermost layer made of low-density polyethylene, a base material layer made of paper, an intermediate layer made of low-density polyethylene, a first adhesive layer, the following chemical formula The barrier layer containing the polyamide resin represented by (1), the second adhesive layer, and the innermost layer made of low-density polyethylene are laminated at least, and the total thickness of the intermediate layer and the innermost layer is 30 to 30 It is a liquid paper container characterized by being 94 μm.

これによれば、中間層及び最内層の層厚の合計を所定の範囲内としたことにより、紙容器の積層体を加熱しても低密度ポリエチレンからなる各層にピンホールが発生しにくくなる。また、バリア層に化学式（１）のポリアミド樹脂を用いることにより、バリア性が高く、強度もある液体用紙容器を提供することができる。さらに、第一接着層及び第二接着層を有することにより、液体用紙容器を構成する各層を強固に接着できる。

According to this, by making the total thickness of the intermediate layer and the innermost layer within a predetermined range, it is difficult for pinholes to occur in each layer made of low-density polyethylene even when the laminate of the paper container is heated. Further, by using the polyamide resin of the chemical formula (1) for the barrier layer, a liquid paper container having high barrier properties and strength can be provided. Furthermore, by having the first adhesive layer and the second adhesive layer, each layer constituting the liquid paper container can be firmly bonded.

  In the liquid paper container of the present invention, the intermediate layer has a layer thickness of 15 to 57 μm.

  According to this, in particular, by making the thickness of the intermediate layer within a predetermined range, it is difficult for pinholes to occur in each layer made of low-density polyethylene even when heated, and the second adhesive layer and the innermost layer Since the layer thickness is relatively thin, a resin odor is generated due to the thickest low-density polyethylene in the innermost layer, and the resin odor is transferred to the contents of the liquid paper container, which may change the taste and flavor of the contents. Is prevented. Moreover, since the flavor of the content adsorbed by the resin is reduced, the taste and flavor are prevented from changing.

  In the liquid paper container of the present invention, the layer thickness of the intermediate layer / the layer thickness of the innermost layer is 0.41 to 3.8.

  According to this, by making the ratio of the layer thickness of the intermediate layer and the layer thickness of the innermost layer within a predetermined range, it is difficult for pinholes to be generated in each layer made of low-density polyethylene even when heated. Since the layer thickness of the two adhesive layers and the innermost layer is relatively thin, a resin odor is generated due to the thickness of the innermost low-density polyethylene, and the resin odor is transferred to the contents of the liquid paper container. The flavor is prevented from changing.

  In the liquid paper container of the present invention, the total thickness of the intermediate layer, the first adhesive layer, the second adhesive layer, and the innermost layer is 43 to 100 μm.

  According to this, by making the total thickness of each layer within the above range, it is possible to prevent the occurrence of pinholes during heating.

  In the liquid paper container of the present invention, the total layer thickness of the intermediate layer and the first adhesive layer is 25 to 60 μm. In the liquid paper container of the present invention, the total layer thickness of the intermediate layer and the first adhesive layer / the total layer thickness of the second adhesive layer and the innermost layer is 0.625 to 3.3. Features.

  According to this, since the ratio of the total layer thickness of the intermediate layer and the first adhesive layer and the total layer thickness of the second adhesive layer and the innermost layer is within a predetermined range, even if heated, from the low density polyethylene Since the pinholes are less likely to occur in each layer, and the layer thickness of the second adhesive layer and the innermost layer is relatively thin, a resin odor is generated due to the thick inner low-density polyethylene, and the resin odor is liquid. It is prevented that the taste and flavor of the contents are changed by moving to the contents of the paper container.

  In order to solve the above problems, the liquid paper container manufacturing method of the present invention comprises, from the outer surface side, an outermost layer made of low-density polyethylene, a base material layer made of paper, an intermediate layer made of low-density polyethylene, and a first adhesive layer The barrier layer containing the polyamide resin represented by the chemical formula (1), the second adhesive layer and the innermost layer made of low density polyethylene are laminated at least, and the total thickness of the intermediate layer and the innermost layer is , 30 to 94 μm, a method for producing a liquid paper container, wherein the intermediate layer, the first adhesive layer, the barrier layer, the second adhesive layer, and the innermost layer are coextruded to the base material layer. It is characterized by that.

  According to this, it is difficult to generate pinholes in each layer made of low-density polyethylene, and has a high barrier property and strength, and a liquid paper container in which each layer constituting the liquid paper container is firmly bonded is manufactured. Can do. In addition, by co-extrusion laminating each layer, the very thin first adhesive layer and second adhesive layer can be stably formed, and the intermediate layer and barrier layer are relatively thick, and other layers are relatively thin. In particular, it is possible to prevent a resin odor from being generated due to the thickest low-density polyethylene in the innermost layer, the resin odor being transferred to the contents of the liquid paper container, and changing the taste and flavor of the contents. .

  The manufacturing method of the liquid paper container which solves the said subject is the outermost layer which consists of low density polyethylene from the outer surface side, the base material layer which consists of paper, the intermediate | middle layer which consists of low density polyethylene, a 1st contact bonding layer, said Chemical formula (1) A barrier layer containing a polyamide resin, a second adhesive layer, and an innermost layer made of low-density polyethylene, and a total thickness of the intermediate layer and the innermost layer is 30 to 94 μm. A method for manufacturing a liquid paper container, characterized in that a film comprising the intermediate layer, the first adhesive layer, the barrier layer, the second adhesive layer, and the innermost layer is sandwich-laminated on the base material layer. And

  According to this, it is difficult to generate pinholes in each layer made of low-density polyethylene, and has a high barrier property and strength, and a liquid paper container in which each layer constituting the liquid paper container is firmly bonded is manufactured. Can do. In addition, a film composed of an intermediate layer, a first adhesive layer, a barrier layer, a second adhesive layer, and an innermost layer can be prepared in advance by a known coextrusion method, inflation method, T-die method, etc. A liquid paper container can be manufactured stably without considering the timing of laminating.

  The manufacturing method of the liquid paper container of the present invention that solves the above problems includes, from the outer surface side, an outermost layer made of low-density polyethylene, a base material layer made of paper, an intermediate layer made of low-density polyethylene, a first adhesive layer, and the above chemical formula The barrier layer containing the polyamide resin represented by (1), the second adhesive layer, and the innermost layer made of low-density polyethylene are laminated at least, and the total thickness of the intermediate layer and the innermost layer is 30 to 30 A method for producing a liquid paper container having a thickness of 94 μm, wherein a layer made of low-density polyethylene is formed on a side of the base material layer not having the outermost layer, and then the intermediate layer, the first adhesive layer, and the barrier A layer, the second adhesive layer, and the innermost layer are laminated.

  According to this, by forming a layer made of low-density polyethylene on the base material layer in advance, the film formed by each method is sandwich-laminated or laminated by coextruding each layer. Even if the temperature is relatively low, it has adhesiveness, and the resin odor can be further reduced. Further, each layer made of the low-density polyethylene bonded functions as an intermediate layer, and the intermediate layer can be formed relatively thick.

  In the method for producing a liquid paper container of the present invention, when the intermediate layer, the first adhesive layer, the barrier layer, the second adhesive layer, and the innermost layer are formed, the thickness is about the barrier layer. Co-extrusion is performed so as to be symmetrical.

  According to this, a process of coextrusion stably by using a five-layer coextruded film having a symmetric thickness around the barrier layer, or by performing coextrusion lamination so that a similar five layer can be formed. It can be performed. At this time, for the materials constituting the five layers, the intermediate layer and the innermost layer are made the same, the first adhesive layer and the second adhesive layer are made the same, and three types (low density polyethylene, adhesive, chemical formula (1) are shown. (Polyamide resin) material is preferably used, and stability during the coextrusion step is further increased.

  According to the liquid paper container and the manufacturing method thereof of the present invention, a pinhole is not easily generated in each layer made of low-density polyethylene even when the laminate of the paper container is heated, and the liquid paper container in which the deterioration of the barrier function is prevented. Can be provided.

  Hereinafter, an example of an embodiment of the present invention will be described with reference to the drawings. FIG. 1 is an explanatory view showing an example of a layer structure of a laminate forming the paper container of the present invention.

  As shown in FIG. 1, the laminated body 10 which forms the liquid paper container of the present invention has an outermost layer 11 made of low density polyethylene, a base material layer 12 made of paper, and an intermediate layer 13 made of low density polyethylene from the outer surface side. The first adhesive layer 14, the barrier layer 15 containing the polyamide resin represented by the following chemical formula (1), the second adhesive layer 16, and the innermost layer 17 made of low density polyethylene are laminated at least. Below, each layer which comprises the laminated body 10 is demonstrated.

The outermost layer 11 is made of low-density polyethylene, protects the outside of the base material layer 12, and is heated and bonded to the innermost layer 17 to be described later at the end portion of the laminate 10. Specific examples of the low density polyethylene (LDPE) include a high-pressure ethylene homopolymer or a copolymer of ethylene and an α-olefin other than ethylene such as propylene, butene, pentene, hexene, octene, 4-methylpentene-1. A linear low density polyethylene (LLDPE) which is a polymer is preferably used. The density of the low-density polyethylene is not particularly limited as long as it is generally referred to as low-density polyethylene, but is about 0.91 to 0.94 g / cm ³ , and its melt index M.D. I. Although it is not specifically limited, Usually, it is about 1-20.

  Although the formation method of the outermost layer 11 is not specifically limited, For example, it forms by carrying out the extrusion coating to one side of the base material layer 12. FIG. The outermost layer 11 is a layer that becomes the surface of the paper container, but a printing layer can be further provided on the surface, and the surface is subjected to, for example, corona treatment in order to improve the adhesion of the printing ink used for the printing layer. It is preferable to perform a surface treatment. Although the thickness of the outermost layer 11 is not specifically limited, Usually, it is about 10-60 micrometers.

The base material layer 12 is made of paper, and since this paper becomes a basic material constituting the paper container, a material having formability, bending resistance, rigidity, waist, strength and the like can be used. As paper, for example, it is a main strength material, and uses various types of paper base materials such as high-size bleached or unbleached paper base, or pure white roll paper, kraft paper, paperboard, processed paper, milk base paper, etc. can do. The base material layer 12 may be a laminate of a plurality of these papers. The paper weighs about 80 to 600 g / m ² , preferably about 100 to 450 g / m ² , and has a thickness of about 110 to 860 μm, preferably about 140 to 640 μm. Note that, for example, letters, figures, symbols, and other desired patterns can be arbitrarily formed on the paper base by a normal printing method.

  The intermediate layer 13 is made of low-density polyethylene and has a function of enhancing the adhesion between the base material layer 12 and the barrier layer 15 and imparting pinhole resistance. As the material of the intermediate layer 13, the same material as the low density polyethylene of the outermost layer 11 can be used. The formation method and thickness of the intermediate layer 13 will be described later.

  The 1st contact bonding layer 14 is provided between the intermediate | middle layer 13 and the barrier layer 15, and improves the adhesiveness of both layers. As the material of the first adhesive layer 14, a material mainly composed of an adhesive polyolefin resin is used. Examples of adhesive polyolefin resins include polyethylene, ethylene-α-olefin copolymers, α-polyolefins such as polypropylene, polybutene, and polyisobutylene, and polydiolefins such as polybutadiene and polyisoprene, and carboxylic acids, carboxylates, and carboxylic acids. Ethylenically unsaturated monomer having carbonyl group based on anhydride, carboxylic acid ester, carboxylic acid amide or imide, aldehyde, ketone, etc. alone or in combination with cyano group; hydroxy group; ether group; A copolymer with one kind or two or more kinds of the body can be used.

More specifically,
A. Ethylenically unsaturated carboxylic acid: acrylic acid, methacrylic acid, maleic acid, fumaric acid, crotonic acid, itaconic acid, citraconic acid, 5-norbornene-2,3-dicarboxylic acid, etc.
B. Ethylenically unsaturated carboxylic anhydride: acrylic anhydride, citraconic anhydride, 5-norbornene-2,3-dicarboxylic anhydride, tetrahydrophthalic anhydride, etc.
C. Ethylenically unsaturated esters: ethyl acrylate, methyl methacrylate, 2-ethylhexyl acrylate, monoethyl or diethyl maleate, vinyl acetate, vinyl propionate, γ-hydroxypropyl methacrylate, β-hydroxyethyl acrylate, glycidyl acrylate, Glycidyl methacrylate, β-N-ethylaminoethyl acrylate, etc.
D. Ethylenically unsaturated amide or imide: acrylamide, methacrylamide, maleimide, etc.
E. Ethylenically unsaturated aldehydes or ketones: Acrolein, methacrolein, vinyl methyl ketone, vinyl butyl ketone, etc., copolymers with ethylenically unsaturated monomers, etc.
Can be used.

  The first adhesive layer 14 containing such an adhesive polyolefin resin may contain a polyolefin resin, particularly polyethylene. In this case, the content of the adhesive polyolefin resin in the first adhesive layer 14 is preferably 40% by mass or more. If the content of the adhesive polyolefin resin is less than 40% by mass, the adhesion with the barrier layer 15 is lowered, which is not preferable. The formation method and thickness of the first adhesive layer 14 will be described later.

  The barrier layer 15 contains a polyamide resin represented by the above chemical formula (1) (hereinafter referred to as nylon MXD6), and ensures strength and gas barrier properties as a container. Nylon MXD6 is a crystalline nylon obtained from a polycondensation reaction of metaxylylenediamine and adipic acid and having an aromatic ring in the main chain. And it has favorable barrier property by the aromatic ring in a principal chain. Further, since nylon MXD6 is a material that may be in direct contact with the liquid contents such as a soft drink, a process such as skiving applied to the end face of the packaging material is unnecessary, and the process can be simplified. Furthermore, since nylon MXD6 has the same strength as nylon, it is not necessary to provide a reinforcing layer, and the manufacturing cost can be reduced.

  Nylon MXD6 is preferably contained in the barrier layer 15 by about 20 to 100% by mass. When the content of nylon MXD6 is less than 20% by mass, sufficient barrier properties cannot be obtained. When the barrier layer 15 is made of nylon MXD6 and another resin, the other resin is, for example, aliphatic nylon other than nylon MXD6, aromatic nylon, ethylene vinyl alcohol copolymer, aromatic polyamide nanocomposite. (For example, Mitsubishi Gas Chemical Co., Ltd. Imperm103), polyamide-based nanocomposites (for example, Ube Industries, Ltd. UBE NCH NYLON 1022C2, 5034C2) and the like are used.

  The thickness of the barrier layer 15 is preferably about 3 to 60 μm. If the thickness of the barrier layer 15 is less than 3 μm, the barrier property cannot be sufficiently exhibited. If the thickness exceeds 60 μm, the paper container becomes hard and difficult to mold, and the cost becomes expensive. It is not preferable. A method for forming the barrier layer 15 will be described later.

  The second adhesive layer 16 is provided between the barrier layer 15 and the innermost layer 17 and improves the adhesion between the two layers. As the material of the second adhesive layer 16, the same material (adhesive) as that of the first adhesive layer 14 can be used. The formation method and thickness of the second adhesive layer 16 will also be described later.

  The innermost layer 17 is made of low density polyethylene, and is a layer for heat-sealing the innermost layers 17 or the innermost layer 17 and the outermost layer 11 when forming the container, and is a layer in contact with the contents of the paper container. It becomes. As the material of the innermost layer 17, the same material as the low density polyethylene of the outermost layer 11 can be used. As described above, since the innermost layer 17 is in contact with the contents of the container, when the contents are milk or the like, low-density polyethylene without additives (non-added low-density polyethylene) is used. The formation method and thickness of the innermost layer 17 will be described later.

  Here, the thickness of the intermediate layer 13, the innermost layer 17, the first adhesive layer 14, and the second adhesive layer 16 will be described in detail. The liquid paper container of the present invention is characterized in that the total thickness of the intermediate layer 13 and the innermost layer 17 is 30 to 94 μm. The total thickness of the intermediate layer 13 and the innermost layer 17 is preferably 40 to 80 μm. Accordingly, since each layer made of low-density polyethylene has a sufficient thickness, even when the laminate 10 is heated, pinholes are hardly generated in each layer.

  In particular, the intermediate layer 13 has a layer thickness of 15 to 57 μm, and the innermost layer 17 has a layer thickness of 15 to 37 μm, so that the innermost layer 17 can be made relatively thin. Further, the ratio of the layer thickness of the intermediate layer 13 to the layer thickness of the innermost layer 17 is set to 0.41 to 3.8, so that the innermost layer 17 can be made relatively thin. Thus, since the polyethylene odor of the innermost layer 17 does not become strong by making the layer thickness of the innermost layer 17 made of low-density polyethylene relatively thin, the odor is prevented from being transferred to the contents of the paper container. When a thing is food and drink, it is prevented that the flavor of food and drink changes. The layer thickness of the intermediate layer 13 is more preferably 25 to 50 μm, and the layer thickness of the innermost layer 17 is more preferably 15 to 30 μm. Further, the ratio of the layer thickness of the intermediate layer 13 to the layer thickness of the innermost layer 17 is preferably 0.83 to 3.33.

  Further, when considering the layer thickness of the laminate 10 of the liquid paper container including the first adhesive layer 14 and the second adhesive layer 16, the intermediate layer 13, the first adhesive layer 14, the second adhesive layer 16, and the innermost layer 17. The total layer thickness is 43 to 100 μm, and preferably 50 to 90 μm. At this time, the total layer thickness of the intermediate layer 13 and the first adhesive layer 14 is 25 to 60 μm, preferably 30 to 55 μm. The total layer thickness of the second adhesive layer 16 and the innermost layer 17 is 18 to 40 μm, preferably 20 to 35 μm. Furthermore, the ratio of the total layer thickness of the intermediate layer 13 and the first adhesive layer 14 / the total layer thickness of the second adhesive layer 16 and the innermost layer 17 is 0.625 to 3.3, preferably 0.86 to 2. 75. Moreover, the thickness of the 1st contact bonding layer 14 is about 3-10 micrometers at this time, and the thickness of the 2nd contact bonding layer 16 is about 3-10 micrometers. In addition, when the thickness of the first adhesive layer 14 or the second adhesive layer 16 is simply added to the thickness of the other layers, the range of the total layer thickness may not be satisfied. It is preferable to adjust each layer thickness within each range.

  Although the thickness of the laminated body 10 which consists of these layer structures is not specifically limited, Usually, it is about 150 micrometers-700 micrometers.

  Here, the formation method of the intermediate | middle layer 13, the 1st contact bonding layer 14, the barrier layer 15, the 2nd contact bonding layer 16, and the innermost layer 17 in the laminated body 10 is demonstrated. The formation method of these five layers 13 to 17 is not particularly limited. For example, the intermediate layer 13, the first adhesive layer 14, the barrier layer 15, the second adhesive layer 16, and the innermost layer 17 may be coextruded and laminated together. it can. When these five layers 13 to 17 are directly formed on the base material layer 12 by coextrusion lamination, the laminating temperature is not particularly limited, but considering the adhesiveness of these layers to the base material layer 12, 300 It is about ~ 320 ° C.

  In addition, as a method for forming these five layers 13 to 17, for example, a film composed of the intermediate layer 13, the first adhesive layer 14, the barrier layer 15, the second adhesive layer 16, and the innermost layer 17 is formed on the base layer 12. Sandwich lamination can also be performed on the side having no outer layer 11. A film composed of these five layers 13 to 17 can be produced by a co-extrusion method, or can be produced by an inflation method or a T-die method.

  In addition, a layer made of low-density polyethylene, which is a part of the intermediate layer 13, is formed in advance on the side of the base material layer 12 that does not have the outermost layer 11, and the other intermediate layers 13, It is also possible to laminate the first adhesive layer 14, the barrier layer 15, the second adhesive layer 16, and the innermost layer 17. At this time, the layer made of low-density polyethylene previously formed on the base material layer 12 and the intermediate layer 13 laminated later function as the intermediate layer 13 and are relatively thick (with the above preferred thickness range). The intermediate layer 13 can be formed. Thus, the lamination at the time of laminating | stacking the five layers 13-17 at the time of having previously formed the layer which consists of low density polyethylene which becomes a part of intermediate | middle layer 13 in the side which does not have the outermost layer 11 of the base material layer 12 Although temperature is not specifically limited, For example, about 280-300 degreeC can be made comparatively low and the resin odor can further be reduced.

  When the intermediate layer 13, the first adhesive layer 14, the barrier layer 15, the second adhesive layer 16, and the innermost layer 17 are laminated, the thicknesses of the five layers 13 to 17 are symmetrical about the barrier layer 15. It is preferable to perform coextrusion. This coextrusion step includes the case where coextrusion lamination is performed and the case where a coextruded film is produced. Thus, a co-extruded film can be stably produced by producing a five-layer co-extruded film having a symmetric thickness around the barrier layer 15 or performing co-extrusion lamination. When co-extrusion is performed in this way, three materials (low density polyethylene, adhesive, polyamide resin represented by chemical formula (1)) are used, and the same material is symmetrically centered on the barrier layer 15 as in the case of thickness. Is preferably used.

  In addition to these, the five layers 13 to 17 are formed by first forming the intermediate layer 13, the first adhesive layer 14 and the barrier layer 15 by coextrusion lamination, and then forming the second adhesive layer 16 and the innermost layer 17 by coextrusion lamination. Can be formed. Alternatively, first, the intermediate layer 13 and the first adhesive layer 14 may be formed by coextrusion lamination, and then the barrier layer 15, the second adhesive layer 16, and the innermost layer 17 may be formed by coextrusion lamination.

  In addition, these five layers 13-17 can also form each layer one by one. Thus, although it is possible to form the five layers 13-17 in the laminated body 10 by various methods, three types of materials (low density polyethylene, an adhesive agent, the polyamide resin shown by Chemical formula (1)) are used. A method using a coextruded laminate or a coextruded film having five layers 13 to 17 is preferably used. By this method, the extremely thin first adhesive layer 14 and second adhesive layer 16 can be easily formed.

  Production of a paper container using the laminate 10 is usually performed as follows. That is, after printing on the outer surface of the sheet of the laminate 10 having the above-described layer configuration, punching and skiving and hemming the end surface so that the contents do not contact the end surface, the bottom and top portions in the filling device Heat seal by hot air heating, flame heating, etc. to make a paper container.

  About the shape of this paper container, what is necessary is just to determine suitably according to a use, the objective, etc. For example, a gable top type, a brick type, a flat top type etc. are mentioned. In addition, for example, a polyethylene cap, a pull tab type opening mechanism, and the like may be appropriately provided at the spout of the paper container.

  The contents of the paper container are not particularly limited, and drinks such as milk, juice, mineral water, green tea, black tea, oolong tea, sake, shochu, etc., cooking oil, soy sauce, mirin, vinegar, seasoning containing solids, etc. Various liquids such as non-food products such as foods, shampoos, rinses and machine oils can be used as the contents.

  The present invention will be described more specifically with reference to examples and comparative examples.

Example 1
A low density polyethylene resin (density: 0.923 g / cm ³ , melt index MI; 3.7) was extrusion coated on one side of a milk base paper weighing 313 g / m ² to form an outermost layer having a thickness of 17 μm. Formed.

Further, on the other side of the milk base paper, an intermediate layer having a thickness of 35 μm made of low-density polyethylene resin (density: 0.923 g / cm ³ , melt index MI; 3.7), an adhesive (Mitsui Chemicals, Inc.) A first adhesive layer having a thickness of 6 μm made of Admer (registered trademark) NF528), a barrier layer having a thickness of 5 μm made of a polyamide resin (nylon MXD6) represented by the above chemical formula (1), and an adhesive (manufactured by Mitsui Chemicals, Inc.) A second adhesive layer of 5.4 μm in thickness composed of Admer (registered trademark) NF528), a thickness of 19 composed of low-density polyethylene resin (density; 0.923 g / cm ³ , melt index MI; 3.7) The innermost layer of 6 μm was coextruded and laminated at 300 ° C. so as to be laminated in this order.

In this way, the laminate of the example was laminated in the order of LDPE 17 μm / paper 313 g / m ² / LDPE 35 μm / first adhesive layer 6 μm / MXD6 5 μm / second adhesive layer 5.4 μm / LDPE 19.6 μm. At this time, the ratio of the layer thickness of the intermediate layer / the layer thickness of the innermost layer is 1.79, and the ratio of the total layer thickness of the intermediate layer and the first adhesive layer / the total layer thickness of the second adhesive layer and the innermost layer. Was 1.64.

(Comparative example)
A laminate of the comparative example was manufactured in the same manner as in the example except that the thickness of the intermediate layer of the example was 8.7 μm and the thickness of the first adhesive layer was 5.4 μm.

(Evaluation method)
About the laminated body of an Example and a comparative example, the generation | occurrence | production condition of pinhole, adhesiveness, and the degree of flavor deterioration were evaluated.

As for the occurrence of pinholes, the laminate was heated to each temperature with hot air (hot air) using a filling machine (manufactured by DNK Corporation, model number: DR-10), and the occurrence of pinholes was examined. The results are shown in Table 1. It should be noted that, with less or no occurrence of pinholes (specifically 1cm 0~1 or so per ²⁾ ○, and that the occurrence of pinholes is a little bit of (specifically 2 to 5 or so per 1cm ²⁾ △ X indicates that pinholes are frequently generated (specifically, 6 or more per 1 cm ² ).

  Adhesion is the same as in the evaluation of pinhole occurrence, using a filling machine (manufactured by DNK Co., model number: DR-10), and when molded into a laminate with hot air (hot air) at each temperature. The adhesion of the top seal part was examined. The results are shown in Table 1. The standard of adhesion was evaluated as ◯ when no interfacial delamination was made between the innermost resin layers, and Δ when partial interfacial delamination was performed.

  The degree of flavor deterioration was filled with 100% orange juice at 340 ° C., stored at 10 ° C. for 1 week, and then subjected to a sensory evaluation test by five panelists. Table 1 shows the average score obtained by scoring each panel from 5 points to 1 in order of decreasing flavor deterioration.

It is sectional drawing which shows an example of the layer structure of the laminated body which forms the paper container of this invention.

Explanation of symbols

10 Laminated body 11 Outermost layer 12 Base material layer (paper layer)
13 Intermediate layer 14 First adhesive layer 15 Barrier layer 16 Second adhesive layer 17 Innermost layer

Claims (5)

From the outer surface side, the outermost layer made of low density polyethylene, the base material layer made of paper, the intermediate layer made of low density polyethylene, the first adhesive layer, the barrier layer containing the polyamide resin represented by the following chemical formula (1), the second An adhesive layer and an innermost layer made of low-density polyethylene, at least laminated,
The total layer thickness of the intermediate layer and the innermost layer is 40 to 80 μm,
The liquid paper container, wherein the intermediate layer has a thickness of 25 to 50 μm, and the innermost layer has a thickness of 15 to 30 μm.

  2. The liquid paper container according to claim 1, wherein a total layer thickness of the intermediate layer and the first adhesive layer is 30 to 55 μm. From the outer surface side, the outermost layer of a low density polyethylene, base layer made of paper, an intermediate layer made of low density polyethylene, a first adhesive layer, a barrier layer containing a polyamide resin represented by the following chemical formula (1), the second The innermost layer made of an adhesive layer and low-density polyethylene is laminated at least, and the total thickness of the intermediate layer and the innermost layer is 40 to 80 μm, and the layer thickness of the intermediate layer is 25 to 50 μm The innermost layer has a layer thickness of 15 to 30 μm, and is a method for manufacturing a liquid paper container,
A method for producing a liquid paper container, wherein the intermediate layer, the first adhesive layer, the barrier layer, the second adhesive layer, and the innermost layer are coextruded and laminated on the base material layer.

From the outer surface side, the outermost layer of a low density polyethylene, base layer made of paper, an intermediate layer made of low density polyethylene, a first adhesive layer, a barrier layer containing a polyamide resin represented by the following chemical formula (1), the second The innermost layer made of an adhesive layer and low-density polyethylene is laminated at least, and the total thickness of the intermediate layer and the innermost layer is 40 to 80 μm, and the layer thickness of the intermediate layer is 25 to 50 μm The innermost layer has a layer thickness of 15 to 30 μm, and is a method for manufacturing a liquid paper container,
A film composed of an intermediate layer, the first adhesive layer, the barrier layer, the second adhesive layer, and the innermost layer prepared by any one of a coextrusion method, an inflation method, and a T-die method is used as the base material. A method for producing a liquid paper container, wherein the laminate is laminated with respect to a layer.

From the outer surface side, the outermost layer of a low density polyethylene, base layer made of paper, an intermediate layer made of low density polyethylene, a first adhesive layer, a barrier layer containing a polyamide resin represented by the following chemical formula (1), the second The innermost layer made of an adhesive layer and low-density polyethylene is laminated at least, and the total thickness of the intermediate layer and the innermost layer is 40 to 80 μm, and the layer thickness of the intermediate layer is 25 to 50 μm The innermost layer has a layer thickness of 15 to 30 μm, and is a method for manufacturing a liquid paper container,
Forming a layer made of low-density polyethylene as one intermediate layer on the side of the base material layer not having the outermost layer, and then forming a layer made of low-density polyethylene as the other intermediate layer, the first adhesive layer, A method for producing a liquid paper container, wherein the barrier layer, the second adhesive layer, and the innermost layer are laminated.

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