Laminate and packaging bag

Abstract

To provide a laminate capable of enhancing pinhole resistance, and a packaging bag.SOLUTION: A laminate 10 forming a packaging bag includes a first surface resin layer 11, a first adhesive resin layer 12 formed by using low-density polyethylene, an intermediate layer 14 formed by using nylon, a second adhesive resin layer 15 formed by using low-density polyethylene, and a second surface resin layer 16 formed by using linear low-density polyethylene, wherein a thickness of the first adhesive resin layer 12 is in a range of 9 μm or more and 15 μm or less, and a thickness of the second adhesive resin layer 15 is in a range of 9 μm or more and 15 μm or less.SELECTED DRAWING: Figure 2

Description

[Technical Field]

[0001] The present invention relates to a laminate and a packaging bag. [Background technology]

[0002] BACKGROUND ART For example, Patent Document 1 discloses a packaging bag used for transporting liquids such as milk. The packaging bag having the configuration disclosed in Patent Document 1 is formed using a laminate comprising a base layer containing a polyolefin resin film, a bonding layer, an intermediate layer made of at least one resin film selected from nylon and polyester, a bonding resin layer, and a sealing layer. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Publication No. 2020-019209 Summary of the Invention [Problem to be solved by the invention]

[0004] In conventional packaging bags, including the packaging bag having the configuration disclosed in Patent Document 1, the locations where bending occurs when the bag is packed in cardboard coincide with the locations where pinholes occur, and linear scratches may occur, unlike friction pinholes. This poses the problem of bending pinholes occurring when the bag is packed bent in the cardboard.

[0005] In view of the above-mentioned problems, an object of the present invention is to provide a laminate and a packaging bag that can improve pinhole resistance. [Means for solving the problem]

[0006] In order to solve the above-mentioned problems, one aspect of the present invention is a laminate comprising a first surface resin layer, a first adhesive resin layer, an intermediate layer, a second adhesive resin layer, and a second surface resin layer. The first surface resin layer is a layer that forms the outer surface of the laminate. The first adhesive resin layer is laminated on one surface of the first surface resin layer and is a layer formed using low-density polyethylene. The intermediate layer is laminated on the surface of the first adhesive resin layer opposite the surface facing the first surface resin layer and is a layer formed using nylon. The second adhesive resin layer is laminated on the surface of the intermediate layer opposite the surface facing the first adhesive resin layer and is a layer formed using low-density polyethylene. The second surface resin layer is laminated on the surface of the second adhesive resin layer opposite the surface facing the intermediate layer and is a layer formed using linear low-density polyethylene. The thickness of the first adhesive resin layer is in the range of 9 μm to 15 μm, and the thickness of the second adhesive resin layer is in the range of 9 μm to 15 μm.

[0007] In order to solve the above-described problems, one aspect of the present invention is a packaging bag formed using the laminate. [Effects of the Invention]

[0008] According to one aspect of the present invention, it is possible to provide a laminate and a packaging bag that can improve pinhole resistance. [Brief explanation of the drawings]

[0009] [Figure 1] 1A and 1B are diagrams illustrating a configuration of a packaging bag in a first embodiment. [Figure 2] 1 is a cross-sectional view showing the configuration of a laminate that forms a packaging bag in a first embodiment. FIG. DETAILED DESCRIPTION OF THE INVENTION

[0010] Hereinafter, embodiments of the present technology will be described with reference to the drawings. In the drawings, identical or similar parts are designated by identical or similar reference numerals, and redundant description will be omitted. Each drawing is a schematic diagram and may differ from the actual product. The embodiments described below exemplify devices and methods for embodying the technical idea of ​​the present technology, and the technical idea of ​​the present technology is not limited to the devices and methods exemplified in the following embodiments. The technical idea of ​​the present technology can be modified in various ways within the technical scope described in the claims. Furthermore, the directions of "left and right" and "up and down" in the following description are merely defined for the convenience of explanation and do not limit the technical idea of ​​the present invention. Therefore, for example, if the page is rotated 90 degrees, "left and right" and "up and down" are read interchangeably, and of course, if the page is rotated 180 degrees, "left" becomes "right" and "right" becomes "left."

[0011] (First embodiment) <Packaging bag> As shown in Fig. 1, the packaging bag 1 is a bag formed using a sheet-like laminate 10, and is used for filling the interior with a liquid such as milk. The specific configuration of the laminate 10 will be described later.

[0012] The packaging bag 1 also has a first sealed portion 1a and a second sealed portion 1b, which are indicated by hatching in FIG. The first seal portion 1a and the second seal portion 1b are formed by, for example, heat welding.

[0013] Note that Figure 1 shows one side of the packaging bag 1 in a side view, but the other side (not shown) does not have a first seal portion 1a that runs vertically through the center (vertical direction in Figure 1), unlike the other side. Furthermore, when forming the packaging bag 1, for example, the first sealed portion 1a is formed to make the sheet-like laminate 10 cylindrical, and then the second sealed portion 1b is formed while filling the contents (liquid, etc.).

[0014] <Laminate> Hereinafter, the configuration of the laminate 10 will be described with reference to Fig. 1 and Fig. 2. In Fig. 2, when the packaging bag 1 is formed using the laminate 10, the surface (outer surface) that will become the outside of the packaging bag 1 is indicated as "outside," and the surface (inner surface) that will become the inside of the packaging bag 1 is indicated as "inside." As shown in FIG. 2, the laminate 10 includes a first surface resin layer 11, a first adhesive resin layer 12, a printing layer 13, an intermediate layer 14, a second adhesive resin layer 15, and a second surface resin layer 16.

[0015] (First surface resin layer) The first surface resin layer 11 is a layer that forms the outer surface of the laminate 10, and is formed using a co-extruded multilayer film (for example, product name: ZPB102C manufactured by Tamapoly Co., Ltd.). Detailed illustration of the co-extruded multilayer film is omitted.

[0016] The co-extruded multilayer film constituting the first surface resin layer 11 includes a first skin layer, a core layer, and a second skin layer.

[0017] The first skin layer forms the outermost surface (the upper surface in FIG. 1) of the first surface resin layer 11 of the multilayer film, and is made of, for example, medium-density polyethylene. The core layer is disposed between the first skin layer and the second skin layer, and is formed using, for example, unstretched nylon.

[0018] The second skin layer is laminated to the core layer and is formed, for example, using medium density polyethylene. The co-extruded multilayer film forming the first surface resin layer 11 may be configured, for example, such that an adhesive resin layer is formed between the first skin layer and the core layer, and between the core layer and the second skin layer.

[0019] (First adhesive resin layer) The first adhesive resin layer 12 is laminated on one side (the lower side in Figure 1) of the first surface resin layer 11 and is formed using low-density polyethylene (for example, product name: LC600A manufactured by Japan Polyethylene Corporation or product name: L417 manufactured by Sumitomo Chemical Co., Ltd.). The thickness of the first adhesive resin layer 12 is within the range of 9 μm to 15 μm.

[0020] The reason why the thickness of the first adhesive resin layer 12 is set to be in the range of 9 μm to 15 μm will be described below. If the thickness of the first adhesive resin layer 12 is less than 9 μm, fisheyes will occur during film formation, and the resulting fisheyes will cause film cracks. Also, if the thickness of the first adhesive resin layer 12 is less than 9 μm, the laminate strength will be reduced, and vibrations occurring during transportation will cause delamination at the rubbing or bending of the cardboard, making it difficult to achieve pinhole resistance throughout the entire layer structure. If the thickness of the first adhesive resin layer 12 exceeds 15 μm, the flexibility of the first adhesive resin layer 12 decreases, making it difficult to obtain bending resistance. Also, the laminate 10 becomes too thick, reducing the machinability.

[0021] In the first embodiment, as an example, a case where the thickness of the first adhesive resin layer 12 is set to 15 μm will be described. The density of the first adhesive resin layer 12 is, for example, 0.93 g / cm 3 ] is as follows.

[0022] (Printing layer) The printed layer 13 is laminated on the surface of the first adhesive resin layer 12 opposite to the surface facing the first surface resin layer 11 (the lower surface in FIG. 1), and is a layer on which a pattern is formed. The print layer 13 is formed by mixing a solvent into Riogran, a product of Toyo Ink Co., Ltd., for example. The printing layer 13 may be configured to be laminated between the first adhesive resin layer 11 and the first surface resin layer 12 .

[0023] (middle class) The intermediate layer 14 is laminated on the surface of the printed layer 13 opposite to the surface facing the first adhesive resin layer 12 (the lower surface in FIG. 1), and is a layer made of nylon. In the first embodiment, as an example, a case where the intermediate layer 14 is formed using a biaxially oriented nylon film will be described. As the biaxially stretched nylon film, for example, Bonyl W, a product name manufactured by Kohjin Film & Chemicals Co., Ltd., can be used.

[0024] (Second adhesive resin layer) The second adhesive resin layer 15 is laminated on the surface of the intermediate layer 14 opposite to the surface facing the printed layer 13 (the lower surface in FIG. 1), and is a layer formed using low-density polyethylene. Examples of low-density polyethylene that can be used include LC600A, a product of Japan Polyethylene Corporation, and L417, a product of Sumitomo Chemical Co., Ltd. The thickness of the second adhesive resin layer 15 is within the range of 9 μm to 15 μm.

[0025] The reason why the thickness of the second adhesive resin layer 15 is set to be in the range of 9 μm or more and 15 μm or less will be described below. If the thickness of the second adhesive resin layer 15 is less than 9 μm, fisheyes will occur during film formation, and the resulting fisheyes will cause film cracks. Also, if the thickness of the second adhesive resin layer 15 is less than 9 μm, the laminate strength will be reduced, and delamination will occur at the rubbing and bending of the cardboard due to vibrations generated during transportation, making it difficult to achieve pinhole resistance throughout the layer structure. If the thickness of the second adhesive resin layer 15 exceeds 15 μm, the flexibility of the second adhesive resin layer 15 decreases, making it difficult to obtain bending resistance. Also, the laminate 10 becomes too thick, reducing the machinability.

[0026] In the first embodiment, as an example, a case where the thickness of the second adhesive resin layer 15 is set to 10 μm will be described. The density of the second adhesive resin layer 15 is, for example, 0.93 g / cm 3 ] is as follows.

[0027] The total thickness of the first adhesive resin layer 12 and the second adhesive resin layer 15 is 25 μm or less. As described above, in the first embodiment, as an example, a case will be described in which the total thickness of the first adhesive resin layer 12 and the second adhesive resin layer 15 is 25 μm.

[0028] (Second surface resin layer) The second surface resin layer 16 is laminated on the surface of the second adhesive resin layer 15 opposite to the surface facing the intermediate layer 14, and is a layer formed using a co-extruded multilayer film made of linear low-density polyethylene (for example, product name: TB320 manufactured by Tamapoly Co., Ltd.). Detailed illustration of the co-extruded multilayer film is omitted. The thickness of the second surface resin layer 16 is, for example, 60 μm.

[0029] The coextruded multilayer film constituting the second surface resin layer 16 includes a first skin layer, a core layer, and a second skin layer. The ratio of the thickness of the first skin layer to the thickness of the core layer to the thickness of the second skin layer is, for example, 1:5:1.

[0030] The core layer is formed by adding, for example, an antioxidant. The density of the core layer is, for example, 0.906 [g / cm 3 ]. The melt flow rate of the core layer is, for example, 1.0 [g / 10 min].

[0031] The first skin layer and the second skin layer are formed by adding, for example, an antiblocking agent and an antioxidant. The density of the first skin layer and the second skin layer is, for example, 0.910 [g / cm 3 ] or more 0.925[g / cm 3 The density of the first skin layer and the second skin layer is preferably within a range of 0.915 [g / cm 3 ] is as follows.

[0032] In the first embodiment, as an example, the density of the first skin layer and the second skin layer is set to 0.922 [g / cm 3 The first skin layer and the second skin layer may have different densities. By controlling the densities of the core layer, the first skin layer, and the second skin layer, it becomes possible to improve the sealing performance and adjust the stiffness, which will be described later. The melt flow rate of the first skin layer and the second skin layer is, for example, 2.0 [g / 10 min]. The co-extruded multilayer film forming the second surface resin layer 16 may be configured, for example, such that an adhesive resin layer is formed between the first skin layer and the core layer, and between the core layer and the second skin layer.

[0033] <Strength> The stiffness of the laminate 10 formed by stacking the first surface resin layer 11, the first adhesive resin layer 12, the intermediate layer 14, the second adhesive resin layer 15, and the second surface resin layer 16 is 70 mN or less. In the first embodiment, a case where the stiffness of the laminate 10 is set to 65 [mN] will be described as an example.

[0034] The reason why the stiffness of the laminate 10 is set to 70 [mN] or less is that if the stiffness of the laminate 10 exceeds 70 [mN] (if the stiffness is too high), it becomes difficult to form the packaging bag 1 when filling the contents, and the machine workability deteriorates. The stiffness is, for example, a value obtained by making a loop from a sample of the laminate 10 having a width of 15 mm and a length of 100 mm without the printed layer 13 formed thereon, and then pressing the sample to a pressing length of 10 mm, and measuring the rebound strength with a loop stiffness tester. Furthermore, the stiffness value measured on a sample of laminate 10 without forming printed layer 13 is almost the same as the stiffness value measured on a sample of laminate 10 with forming printed layer 13.

[0035] The above-described first embodiment is one example of the present invention, and the present invention is not limited to the above-described first embodiment. Various modifications can be made depending on the design, etc., even in forms other than the first embodiment, as long as they do not deviate from the technical idea of ​​the present invention.

[0036] (Effects of the first embodiment) The laminate 10 of the first embodiment can achieve the effects described below. (1) The laminated sheet includes a first surface resin layer 11, a first adhesive resin layer 12, an intermediate layer 14 formed using nylon, a second adhesive resin layer 15, and a second surface resin layer 16. The thickness of the first adhesive resin layer 12 is within a range of 9 μm to 15 μm, and the thickness of the second adhesive resin layer 15 is within a range of 9 μm to 15 μm. Therefore, by alternately arranging (stacking) the tough intermediate layer 14 and the flexible first adhesive resin layer 12 and second adhesive resin layer 15, it becomes possible to exhibit pinhole resistance in a state where bending and friction occur in combination. Note that a state where bending and friction occur in combination is, for example, a state where the packaging bag 1 is bent inside a packed box, where packaging bags 1 rub against each other, or where the packaging bag 1 rubs against cardboard, etc.

[0037] Furthermore, since the thickness of the first adhesive resin layer 12 and the thickness of the second adhesive resin layer 15 are within the range of 9 μm or more and 15 μm or less, it is possible to improve pinhole resistance and suppress a decrease in machine readiness. As a result, it is possible to provide a laminate 10 that can improve pinhole resistance.

[0038] (2) The total thickness of the first adhesive resin layer 12 and the second adhesive resin layer 15 is 25 μm or less. As a result, it is possible to manufacture the packaging bag 1 using a general conventional bag-making machine. This makes it possible to manufacture the packaging bag 1 without, for example, changing the bag-making machine at the customer's site.

[0039] (3) The stiffness of the laminated first surface resin layer 11, first adhesive resin layer 12, intermediate layer 14, second adhesive resin layer 15, and second surface resin layer 16 is 70 mN or less. As a result, it is possible to suppress a decrease in machine readiness.

[0040] The packaging bag 1 of the first embodiment can achieve the effects described below. (4) It is formed using the laminate 10. As a result, it is possible to provide a packaging bag 1 that can improve pinhole resistance.

[0041] <Modification of the first embodiment> (1) In the first embodiment, the second surface resin layer 16 is formed using a co-extruded multilayer film, but this is not limiting. That is, the second surface resin layer 16 may be formed using a monolayer film. (2) In the first embodiment, the second adhesive resin layer 15 is formed first, followed by the second surface resin layer 16. However, the present invention is not limited to this. That is, the second adhesive resin layer 15 and the second surface resin layer 16 may be simultaneously formed by co-extrusion lamination. [Example]

[0042] The laminates of Examples 1 and 2 and the laminates of Comparative Examples 1 to 3 will be described below with reference to the first embodiment.

[0043] Example 1 The laminate of Example 1 was formed to have the same configuration as that of the first embodiment, i.e., the thickness of the first adhesive resin layer was 15 μm, the thickness of the second adhesive resin layer was 10 μm, and the stiffness was 65 mN.

[0044] Example 2 A laminate of Example 2 was formed in the same manner as in Example 1, except that the thickness of the first adhesive resin layer was set to 10 [μm] and the stiffness was set to 58 [mN].

[0045] (Comparative Example 1) A laminate of Comparative Example 1 was formed in the same manner as in Example 1, except that the thickness of the second adhesive resin layer was set to 20 [μm] and the stiffness was set to 80 [mN].

[0046] (Comparative Example 2) A laminate of Comparative Example 2 was formed in the same manner as in Example 1, except that the thickness of the first adhesive resin layer was set to 7 [μm] and the stiffness was set to 55 [mN].

[0047] (Comparative Example 3) The laminate of Comparative Example 3 was formed in the same manner as in Example 1, except that an adhesive layer using a solventless laminate was formed instead of the second adhesive resin layer and the stiffness was set to 59 mN.

[0048] (Performance evaluation, evaluation results) The pinhole resistance, appearance, and machining properties were evaluated for each of the laminates of Examples 1 and 2 and the laminates of Comparative Examples 1 to 3. The evaluation results are shown in Table 1. The evaluation methods used were as follows.

[0049] <Pinhole resistance> The pinhole resistance was evaluated by leaving the laminate in an environment of 20°C for 10 hours, folding it in four, and then performing an abrasion test in which the corners of the folded laminate were placed against a piece of corrugated cardboard (B-flute cardboard) and moved back and forth perpendicular to the corrugations. The occurrence of pinholes was then visually confirmed and evaluated.

[0050] The abrasion test conditions were set as follows: load 100 g, abrasion speed 100 mm / sec, abrasion distance 140 mm (70 mm one way), and abrasion reciprocation number 1000. Ten samples each for the example and comparative example were evaluated, and the number of samples in which pinholes occurred was compared. If the pinhole incidence rate was less than 10%, it was evaluated as "Good", if the pinhole incidence rate was between 10% and 40%, it was evaluated as "Average", and if the pinhole incidence rate was more than 40%, it was evaluated as "Poor".

[0051] <Appearance> The appearance was evaluated by visual inspection. Cases where there were no problems were rated as "Good", cases where it was undesirable because there was an expected risk of film cracking or lamination lifting were rated as "Good", and cases where film cracking or lamination lifting actually occurred were rated as "Poor".

[0052] <Machine in progress> The machine readiness was evaluated based on whether or not the product could be put into a filling machine without any problems. Cases where there were no problems were rated as "Good", cases where the stiffness was too high and the packaging material was difficult to form, which was undesirable, were rated as "Good", and cases where the stiffness was too high and the packaging material could not be formed, were rated as "Poor".

[0053] [Table 1]

[0054] As a result of evaluating various performances using the above-mentioned methods, the laminates of Examples 1 and 2 exhibited excellent performance for each evaluation item. That is, it was confirmed that the laminates of Examples 1 and 2 had no problems with appearance and machining properties and had improved pinhole resistance compared to the comparative example.

[0055] On the other hand, the laminate of Comparative Example 1 was too thick, resulting in poor machining properties, and the extruded resin layer had low flexibility, resulting in reduced bending resistance and therefore reduced pinhole resistance. Furthermore, it was confirmed that the appearance of the laminate of Comparative Example 2 was deteriorated due to the insufficient thickness of the first adhesive resin layer. Specifically, fisheyes were generated when the resin was extruded to form the first adhesive resin layer, and film cracks and lifting occurred from the generated fisheyes. Furthermore, it was confirmed that the laminate of Comparative Example 3 did not have a second adhesive resin layer, and therefore had low flexibility and reduced bending resistance, resulting in reduced pinhole resistance.

[0056] The present technology can be configured as follows. (1) a first surface resin layer; a first adhesive resin layer laminated on one surface of the first surface resin layer and formed using low-density polyethylene; an intermediate layer formed of nylon and laminated on a surface of the first adhesive resin layer opposite to a surface facing the first surface resin layer; a second adhesive resin layer formed of low-density polyethylene and laminated on a surface of the intermediate layer opposite to the surface facing the first adhesive resin layer; a second surface resin layer formed using linear low-density polyethylene and laminated on a surface of the second adhesive resin layer opposite to the surface facing the intermediate layer, The thickness of the first adhesive resin layer is in the range of 9 μm or more and 15 μm or less, The thickness of the second adhesive resin layer is in the range of 9 μm or more and 15 μm or less. (2) The laminate according to (1) above, wherein the total thickness of the first adhesive resin layer and the second adhesive resin layer is 25 μm or less. (3) The laminate according to (1) or (2), wherein the stiffness of the laminated first surface resin layer, the first adhesive resin layer, the intermediate layer, the second adhesive resin layer, and the second surface resin layer is 70 mN or less. (4) A packaging bag formed using the laminate according to any one of (1) to (3) above. [Explanation of symbols]

[0057] 1...packaging bag, 1a...first sealed portion, 1b...second sealed portion, 10...laminated body, 11...first surface resin layer, 12...first adhesive resin layer, 13...printed layer, 14...intermediate layer, 15...second adhesive resin layer, 16...second surface resin layer

Claims

1. a first surface resin layer; a first adhesive resin layer laminated on one surface of the first surface resin layer and formed using low-density polyethylene; an intermediate layer formed of nylon and laminated on a surface of the first adhesive resin layer opposite to a surface facing the first surface resin layer; a second adhesive resin layer formed of low-density polyethylene and laminated on a surface of the intermediate layer opposite to the surface facing the first adhesive resin layer; a second surface resin layer formed using linear low-density polyethylene and laminated on a surface of the second adhesive resin layer opposite to the surface facing the intermediate layer, the thickness of the first adhesive resin layer is in the range of 9 μm or more and 15 μm or less; A laminate in which the thickness of the second adhesive resin layer is in the range of 9 μm or more and 15 μm or less.

2. 2. The laminate according to claim 1, wherein the sum of the thickness of the first adhesive resin layer and the thickness of the second adhesive resin layer is 25 [mu]m or less.

3. The laminate according to claim 1, wherein the stiffness of the laminated state of the first surface resin layer, the first adhesive resin layer, the intermediate layer, the second adhesive resin layer, and the second surface resin layer is 70 mN or less.

4. A packaging bag formed using the laminate according to any one of claims 1 to 3.

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