Laminate and packaging container

Abstract

To provide a laminate capable of forming a packaging container having excellent hand tearability on opening.SOLUTION: A laminate 1 includes a paper substrate 11, an intermediate layer 12 fixed to one surface of the substrate 11 via a first adhesive layer 14, and a sealant layer 13 fixed to the intermediate layer 12 on the opposite side of the substrate 11 via a second adhesive layer 15, wherein an elastic modulus of the second adhesive layer 15 is 2.3 MPa or more.SELECTED DRAWING: Figure 1

Description

[Technical Field]

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

[0002] Traditionally, canned or bottled foods, as well as retort pouches made of laminated sheets with aluminum foil sandwiched between various plastic films, have been used as packaging containers for long-term storage ready meals, such as baby food, nursing care food, and stewed dishes like curry and fish. In recent years, many retort pouches have been distributed, using plastic films coated with alumina or silica, which can be used in microwave ovens, as the base material for the laminated sheet. Furthermore, with the recent rise in disaster prevention awareness, the ability to consume food directly from the storage container has become important as a function of emergency food storage.

[0003] However, when the substrate is a plastic film, a thick plastic film must be used to obtain a packaging container that can stand stably on its own in the palm of one's hand, which increases the difficulty of disposal and places a greater burden on the environment.Using paper as the substrate can reduce the burden on the environment, but there is a problem with making it stand stably.

[0004] In response to this, Patent Document 1 discloses a packaging container that uses paper as a base material and can stand stably on its own. Patent Document 1 also discloses a method for manufacturing this packaging container, in which a laminated sheet having at least a base material, a barrier layer, and a sealant layer laminated in this order is cut into a predetermined shape, the cut laminated sheet is folded with the sealant layer on the inside, and then the overlapping edges of the sealant layer are sealed together.

[0005] On the other hand, Patent Document 2 discloses an easily tearable laminate that is a laminate including a base film layer, an adhesive layer, and a sealant layer, in which the adhesive layer contains a reaction product of a polyol compound and a polyisocyanate compound, and is formed using an adhesive in which the equivalent ratio of the hydroxyl groups of the polyol compound to the isocyanate groups of the polyisocyanate compound is 1:3 to 1:18, and the adhesive layer is formed to a predetermined amount.

[0006] Furthermore, Patent Document 3 discloses that various types of plastic films, or a plastic film and a metal-deposited film or a metal foil, are bonded together using an adhesive containing a specific polyol component and two or more types of aliphatic polyisocyanate components to form a laminate for a flexible packaging material used to package contents such as food, medical supplies, and cosmetics. [Prior art documents] [Patent documents]

[0007] [Patent Document 1] WO2018 / 230621 Brochure [Patent Document 2] Japanese Patent Application Publication No. 2018-8422 [Patent Document 3] Japanese Patent Application Publication No. 2019-112567 Summary of the Invention [Problem to be solved by the invention]

[0008] However, the use of paper as a substrate has led to problems that did not arise when a plastic film was used. Specifically, it was found that in packaging containers formed from laminates using a paper substrate, the sealant layer stretches too much when opened, resulting in poor hand-tearability. In other words, there is room for improvement in the hand-tearability of packaging containers formed from laminates using a paper substrate when opened.

[0009] An object of the present invention is to provide a laminate that can be used to form a packaging container that is easy to tear by hand when opening. [Means for solving the problem]

[0010] In order to solve the above problems, a first aspect of the present invention provides a laminate including a paper substrate, an intermediate layer fixed to one surface of the substrate via a first adhesive layer, and a sealant layer fixed to the surface of the intermediate layer opposite the substrate via a second adhesive layer, wherein the elastic modulus of the second adhesive layer is 2.3 MPa or more. The elastic modulus of the second adhesive layer can be measured using an atomic force microscope. [Effects of the Invention]

[0011] According to the present invention, a laminate can be provided that can form a packaging container that is easy to tear by hand when opening. [Brief explanation of the drawings]

[0012] [Figure 1] 1 is a cross-sectional view showing a laminate according to an embodiment of the present invention. [Figure 2] 1 is a front view of a packaging container according to an embodiment of the present invention. [Figure 3] FIG. 2 is a rear view of the packaging container according to the embodiment of the present invention. [Figure 4] 1 is a perspective view showing a method for assembling a packaging container according to an embodiment of the present invention. [Figure 5] FIG. 2 is a cross-sectional view taken along line II-II of FIG. [Figure 6] FIG. 3 is a cross-sectional view taken along the line III-III in FIG. 2. [Figure 7] 1A to 1C are diagrams illustrating a method for manufacturing a packaging container according to an embodiment of the present invention. [Figure 8] 1A to 1C are diagrams illustrating a method for manufacturing a packaging container according to an embodiment of the present invention. DETAILED DESCRIPTION OF THE INVENTION

[0013] Hereinafter, embodiments of the present invention will be described with reference to the drawings. Note that the present invention is not limited to the embodiments described below, and modifications such as design changes can be made based on the knowledge of those skilled in the art. Such modified embodiments are also included in the scope of the present invention. In addition, the drawings are appropriately exaggerated to facilitate understanding.

[0014] [Configuration of laminate and packaging container according to embodiment] 1, the laminate 1 of this embodiment is composed of a paper substrate 11, an intermediate layer 12, a sealant layer 13, a first adhesive layer 14, and a second adhesive layer 15. The intermediate layer 12 is fixed to one surface of the substrate 11 via the first adhesive layer 14. The sealant layer 13 is fixed to the surface of the intermediate layer 12 opposite the substrate 11 via the second adhesive layer 15.

[0015] The substrate 11 provides rigidity to the laminate 1. The substrate 11 is, for example, a sheet having a basis weight of 60 to 140 g / m 2 When a retort pouch is produced using the laminate 1, paper that can withstand retort (heat treatment) is used.

[0016] For example, a barrier layer having excellent barrier properties against oxygen, ultraviolet rays, etc. is used as the intermediate layer 12. For example, a barrier film having a thickness of about 12 μm made of plastic (PET, PP, PE, or nylon) and a vapor-deposited film of an inorganic compound (alumina or silica) as a barrier coating layer is used as the barrier layer.

[0017] The sealant layer 13 provides thermocompression bonding and sealing properties to the laminate 1, and may be made of, for example, a polyolefin film. A more specific example is a non-oriented polypropylene film (CPP film) having a thickness of 60 μm or more.

[0018] The first adhesive layer 14 is a layer made of a reaction product of a polyol and a diisocyanate. The first adhesive layer 14 is formed by disposing and curing a two-component adhesive, whose main agent is a polyol and whose curing agent is a reaction product of a diisocyanate, between the substrate 11 and the intermediate layer 12. In other words, the adhesive used to form the first adhesive layer 14 is a two-component adhesive, whose main agent is a polyol and whose curing agent is a reaction product of isophorone diisocyanate.

[0019] The thickness of the first adhesive layer 14 is preferably 0.3 μm or more, more preferably 0.5 μm or more, and even more preferably 1.0 μm or more, and is preferably 10 μm or less, more preferably 5 μm or less, and even more preferably 3 μm or less, as the upper limit. A preferred range for the thickness of the first adhesive layer 14 is 0.5 μm or more and 10 μm or less.

[0020] The modulus of elasticity of the second adhesive layer 15 is 2.3 MPa or more. The second adhesive layer 15 can be formed by disposing and curing, for example, a two-component adhesive whose main agent is a polyol and whose curing agent is a reaction product of a diisocyanate, between the intermediate layer 12 and the sealant layer 13. In other words, the adhesive that forms the second adhesive layer 15 can be a two-component adhesive whose main agent is a polyol and whose curing agent is a reaction product of a diisocyanate.

[0021] Examples of polyols that make up two-component adhesives in which the base agent is a polyol and the curing agent is a product containing a reaction of diisocyanate include polyester polyol, polyurethane polyol, and a mixture of polyester polyol and polyurethane polyol. Examples of curing agents containing diisocyanate include those obtained by pre-reacting diisocyanate (difunctional isocyanate monomer) to form a trifunctional trimer (a mixture of adduct, biuret, and isocyanurate), and the reaction product of diisocyanate also contains unreacted diisocyanate.

[0022] The thickness of the second adhesive layer 15 is preferably 0.3 μm or more, more preferably 0.5 μm or more, and even more preferably 1.0 μm or more, and is preferably 10 μm or less, more preferably 5 μm or less, and even more preferably 3 μm or less, as the lower limit. A preferred range for the thickness of the second adhesive layer 15 is 0.5 μm or more and 10 μm or less.

[0023] 2 and 3, the packaging container 10 of this embodiment includes a front portion 21, a back portion 22, and a bottom portion 23 folded inward of the front portion 21 and the back portion 22 from one end side to the other end side in a first direction (X direction) of the front portion 21 and the back portion 22. Each of the front portion 21 and the back portion 22 has a height in the first direction (X direction) and a width in a second direction (Y direction) perpendicular to the first direction, in the same plane.

[0024] In this embodiment, the first direction, the X direction, is sometimes referred to as the height direction, and the second direction, the Y direction, is sometimes referred to as the width direction. Therefore, the bottom surface portion 23 is provided on one end side (one side side) of one end side (one side side) and the other end side (the other side side) located opposite each other in the height direction (X direction) of each of the front surface portion 21 and the back surface portion 22. The bottom surface portion 23 is folded in half inside each of the front surface portion 21 and the back surface portion 22 so that the first portion 23a and the second portion 23b face each other (see FIG. 4(c)).

[0025] The packaging container 10 also has side seal portions 24 formed by doubling and sealing the edges (hereinafter sometimes simply referred to as edges) in the width direction of each of the front portion 21 and the back portion 22, and a bottom seal portion 25 formed by doubling and sealing the edges (hereinafter sometimes simply referred to as edges) of the front portion 21 and the back portion 22 and the edges (hereinafter sometimes simply referred to as edges) in the width direction of the bottom portion 23. In Figures 2 and 3, the side seal portions 24, the bottom seal portion 25, and a reinforcing seal portion 25a, which will be described later, are shown shaded.

[0026] The side seal portion 24 and the bottom seal portion 25 are provided on two edges located on opposite sides in the width direction (Y direction) of the front portion 21 and the back portion 22. The bottom seal portion 25 extends from one end side (one side side) of the front portion 21 and the back portion 22 toward the other end side (other side side), and the side seal portion 24 is connected to the bottom seal portion 25 and extends from the bottom seal portion 25 toward the other end side of the front portion 21 and the back portion 22.

[0027] The bottom fold depth h when the bottom surface portion 23 is folded 23 That is, the length of the bottom seal portion 25 is the height h of the front portion 21 and the rear portion 22. 22 It is preferable that the width is 10 to 40% of the width. If it is less than 10%, which is narrower than this range, the bottom surface portion 23 will be narrow when opened, and the packaging container 10 will not be able to stand on its own stably. If it is more than 40%, which is wider than this range, when the folded-in bottom surface portion 23 is opened, the bottom surface portion 23 will not open completely, and the packaging container 10 will not be able to stand on its own stably. A more preferable range is 15 to 25%. Within this range, the self-standing ability will be further improved.

[0028] The packaging container 10 also has a reinforcing seal portion 25a formed by doubly overlapping and sealing the first portion 23a of the bottom portion 23 and the front portion 21, and a reinforcing seal portion 25b formed by doubly overlapping and sealing the second portion 23b of the bottom portion 23 and the back portion 22.

[0029] The reinforcing seal portions 25a, 25b are provided on two edge sides located on opposite sides in the width direction of the front portion 21 and the back portion 22. The reinforcing seal portions 25a, 25b provided on one edge side of the front portion 21 and the back portion 22 extend from one end side of the front portion 21 and the back portion 22 to one of the bottom seal portions 25 and are connected to one of the bottom seal portions 25.

[0030] The reinforcing seal portions 25a, 25b provided on the other edge side of the front portion 21 and the back portion 22 extend from one end side of the front portion 21 and the back portion 22 to the other bottom seal portion 25 and are connected to the other bottom seal portion 25.

[0031] The packaging container 10 is also provided with a storage section 30 that is surrounded by a front section 21, a back section 22, and a bottom section 23, and is formed by sealing the front section 21, the back section 22, and the bottom section 23 with a side seal section 24 and a bottom seal section 25. The side seal section 24, the bottom seal section 25, and the reinforcing seal sections 25a, 25b are formed by thermocompression bonding, ultrasonic welding, or the like.

[0032] At the boundary between the bottom seal portion 25 and the side seal portion 24, a point seal portion 26 for improving sealing performance is provided across the bottom seal portion 25 and the side seal portion 24. The point seal portion 26 is preferably formed with a width that is 40 to 90% of the seal width of the bottom seal portion 25 and the side seal portion 24. The point seal portion 26 is provided on each of the two widthwise edge sides of the front portion 21 and the back portion 22.

[0033] Furthermore, it is preferable that the ratio of the length of the bottom seal portion 25 in the X direction to the overall length of the point seal portion 26 in the X direction, which is provided across the side seal portion 24 and the bottom seal portion 25, is 10% or more. If it is less than 10%, the strength will be insufficient, and there is a high possibility that the food or drink (contents) in the storage portion 30 will leak when the packaging container 10 is dropped.

[0034] When sealing is performed by thermocompression or ultrasonic welding, the sealant layers 13 are fused together as shown in Figure 5, so the sealing line is not clearly visible from the outer surface of the packaging container 10 (the surface of the packaging paper 2 facing the base material 11). Therefore, the design of the outer surface of the packaging container 10 is not impaired.

[0035] 2 and 3, a cutout 27 is provided in each of the two bottom seal portions 25. As shown in Fig. 6, the bottom portion 23 is required to bond the substrates 11 together, and the cutout 27 allows the sealant layer 13 of the bottom seal portion 25 to be exposed on the bottom portion 23 side. That is, in the bottom seal portion 25, the sealant layers 13 of the front portion 21 and the back portion 22 can be fused to each other through the cutouts 27, 27 provided in the first portion 23a and the second portion 23b of the bottom portion 23.

[0036] The cutout portion 27 is formed to a bottom fold depth h from the lower end of the bottom seal portion 25. 23 It is preferable that the cutout be located at a position between 5 and 50% of the width of the bag. If the cutout is located below this range, not only will the cutout area not be sufficient, but the impact of the drop will be concentrated in the drop test, weakening the bag's breakage strength. If the cutout is located above this range, the weight of the contents will cause the unsealed underside of the bottom to open, making it difficult for the bag to stand on its own. A more preferable range is 5 to 30%, and an even more preferable range is 10 to 20%. Within this range, both the bag's breakage strength in the drop test and its self-standing stability will be further improved.

[0037] In this embodiment, the cutout portion 27 is composed of a wide slit (strip-shaped cutout area) cut inward from the edge of the bottom seal portion 25 with a predetermined width, but it may also be composed of a through hole with a planar shape such as a circle or ellipse.

[0038] A hermetic seal section 28 is provided on the other end side of the front section 21 and the back section 22, which overlaps and seals the front section 21 and the back section 22 in two layers to hermetically seal the storage section 30 after the food has been placed in the storage section 30. In addition, at least one of the two side seal sections 24 is provided with a cutout section 29 for cutting off the upper side of the front section 21 and the back section 22 to open the upper side of the storage section when removing the food from the storage section 30 after retort (heat treatment).

[0039] As shown in Figure 4, the packaging container 10 of this embodiment is formed by using a single sheet of packaging paper 2 cut out from the laminate 1 and performing a folding process and a sealing process with the sealant layer 13 facing inward.

[0040] As shown in FIG. 4(a), the wrapping paper 2 has a front portion 21, a bottom portion 23 (first portion 23a, second portion 23b), and a back portion 22, arranged in this order in the longitudinal direction (first direction). The front portion 21 and the back portion 22 are provided with hermetic seal portions 28 at both ends of the wrapping paper 2 in the longitudinal direction. Bottom seal portions 25 are provided at both ends of the width direction (second direction) of each of the first portion 23a and the second portion 23b. Side seal portions 24 and bottom seal portions 25 are provided at both ends of the width direction of each of the front portion 21 and the back portion 22.

[0041] Of these, the side seals 24 are located on both ends in the longitudinal direction (first direction) of the packaging paper 2. That is, along the longitudinal direction of the packaging paper 2, the side seals 24, bottom seal 25, bottom seal 25, bottom seal 25, bottom seal 25, and side seal 24 are provided in this order.

[0042] The longitudinal dimension (first direction) of the bottom seal portion 25 is set to be approximately equal to the dimensions of the first portion 23a and the second portion 23b along the longitudinal direction (first direction) of the packaging paper 2. It is preferable that the longitudinal dimension (first direction) of the bottom seal portion 25 provided on the front portion 21 and the back portion 22 is approximately equal to the longitudinal dimension (first direction) of the bottom seal portion 25 provided on the bottom portion 23.

[0043] Next, as shown in Figure 4(b), the first portion 23a and the second portion 23b are mountain-folded, and the front portion 21, the back portion 22, and the bottom portion 23 are valley-folded, thereby folding the packaging paper 2 so that it has a W-shape when viewed from the side, with the front portion 21 and the back portion 22 facing each other.

[0044] Next, as shown in Figure 4(c), the side seal portions 24 at one widthwise end of the packaging paper 2 are brought into close contact with each other, and the bottom seal portions 25 at the front portion 21 and back portion 22 are brought into close contact with the bottom seal portion 25 at the bottom portion 23, and are secured together by, for example, thermocompression or ultrasonic welding. Subsequently, the side seal portion 24 and the bottom seal portion 25 at the other widthwise end of the packaging paper 2 are secured together in the same manner, thereby obtaining a packaging container 10 in the form shown in Figure 4(d).

[0045] [Actions and Effects of the Laminate and Packaging Container of the Embodiment] The laminate 1 of this embodiment includes a paper substrate 11, but because the modulus of elasticity of the second adhesive layer 15 is 2.3 MPa or more, the sealant layer 13 of the packaging container 10 obtained using this is prevented from stretching too much when opened. In other words, the laminate 1 of this embodiment can form a packaging container 10 that is easy to tear by hand when opened. The packaging container 10 of this embodiment is expected to be easy to tear by hand when opened.

[0046] In addition, the sealant layer of a retort pouch is more stretchable than that of a normal packaging container, and the material is denatured during the retort treatment, making it difficult to open. Therefore, when the packaging container 10 is a retort pouch, a greater effect can be obtained compared to when it is not.

[0047] Furthermore, the packaging container 10 is bag-shaped and includes a storage section 30 with openings at both ends in the longitudinal direction (first direction) of the paper wrapper 2. As shown in Fig. 4(e), when the opening is widened and the first portion 23a and the second portion 23b are pressed from within the storage section 30, most of the first portion 23a and the second portion 23b come into contact with the surface on which the packaging container 10 is placed, helping the packaging container 10 to stand upright. After the food is placed in the storage section 30, the packaging container 10 is sealed by, for example, depressurizing the storage section 30 and then fixing the hermetic seal portions 28 shown in Fig. 4(a) together in the same manner as the side seal portions 24 and the bottom seal portion 25.

[0048] When packaging container 10 is placed upright with bottom surface 23 facing downwards while fluid food is contained in storage section 30, the food moves toward bottom surface 23. The movement of the food increases the internal pressure on the bottom surface 23 side of storage section 30, causing bottom surface 23, which had been folded inside front surface 21 and back surface 22, to open and one end side (bottom surface 23 side) of storage section 30 to expand. This allows packaging container 10 to stand on its own with bottom surface 23 facing downwards.

[0049] Furthermore, packaging paper 2 cut out from a laminate 1 having a paper substrate 11 is used to produce the packaging container 10. By using a paper substrate, the total amount of plastic film can be reduced, and therefore the packaging container 10 of this embodiment has a smaller environmental impact.

[0050] Furthermore, since the bottom portion 23 of the packaging container 10 is folded from the front portion 21 and the back portion 22 into the inside of the front portion 21 and the back portion 22, the sealing portion where the front portion 21 and the back portion 22 and the bottom portion 23 are overlapped and sealed does not exist on one end side of the front portion 21 and the back portion 22.

[0051] When a seal portion is present on one end side of front portion 21 and back portion 22, if the packaging container is placed upright with bottom portion 23 facing downwards, bottom portion 23 of packaging container 10 will be raised above the installation surface where it comes into contact with, for example, a microwave oven turntable. In other words, a part of bottom portion 23 will be separated (floating) from the turntable. Because microwave ovens have a high heating power on the installation surface side, a packaging container with a raised bottom portion above the installation surface will affect the heating of food.

[0052] In contrast, the packaging container 10 of this embodiment does not have a sealing portion on one end side of the front portion 21 and the back portion 22, and the bottom portion 23 is not raised from the installation surface, so heating in a microwave oven can be performed more efficiently than when a sealing portion is present on one end side of the front portion 21 and the back portion 22.

[0053] Here, the packaging container 10 of this embodiment uses a paper substrate as the substrate 11 of the laminate 1. In this case, it can be heated in a microwave oven. Conventionally, a laminated sheet in which aluminum foil is sandwiched between various plastic films has been known, but this cannot be heated in a microwave oven. Also known is a product that uses an alumina or silica vapor-deposited film that can be heated in a microwave oven, but this alumina or silica vapor-deposited film is thin and therefore weak, making it difficult for the packaging container to stand upright, especially in the palm of one's hand. On the other hand, the packaging container 10 of this embodiment is strong, and in emergencies or disasters, it is possible to eat or drink directly from the storage container.

[0054] Furthermore, since the packaging container 10 of this embodiment uses a paper substrate as the substrate 11 of the laminate 1, the patterns drawn on the front portion 21 and the back portion 22 do not change even after heat treatment. It is also possible to write names, text, etc. on the front portion 21 and the back portion 22. It is also environmentally friendly and does not require excessive packaging. It is also lightweight and, from an environmental perspective, is useful as a substitute for cans and bottles due to its low transportation costs and ease of disposal.

[0055] [Method for manufacturing laminate and packaging container according to the embodiment] Next, the method for manufacturing the laminate 1 and the packaging container 10 will be further described with reference to FIGS.

[0056] The method for manufacturing the packaging container 10 includes a step (step A) of forming the laminate 1 shown in Fig. 1, a step (step B) of cutting out the laminate 1 to obtain packaging paper 2, and a step (step C) of forming the packaging container 10 from the packaging paper 2. Step A is a method for manufacturing the laminate 1. In other words, the method for manufacturing the packaging container 10 includes a method for manufacturing the laminate 1.

[0057] In step A (first step), a two-component adhesive, the main agent of which is a reaction product of a polyol and a curing agent of a diisocyanate, is used to perform dry lamination to obtain a laminate 1. Specifically, the two-component adhesive is first applied to a substrate 11 to laminate an intermediate layer (barrier layer) 12, and then the two-component adhesive is applied to the intermediate layer 12 side of the obtained laminate to laminate a sealant layer 13.

[0058] In step B, the laminate 1 is cut out to obtain the paper wrapping sheet 2 shown in Figure 7(a). The planar shape of this paper wrapping sheet 2 is a rectangle whose dimension in the X direction (height direction) is longer than its dimension in the Y direction (width direction). Folding lines are set in the paper wrapping sheet 2 so that it is divided along the X direction into a front surface 21, a first portion 23a and a second portion 23b of the bottom surface 23, and a back surface 22, in that order.

[0059] 7(b), the paper wrapper 2 is first folded in two so that the front portion 21, the back portion 22, and the first portion 23a and the second portion 23b of the bottom portion 23 overlap each other. The paper wrapper 2 is folded so that the sealant layers 13 of one half and the other half face each other, with the fold line between the first portion 23a and the second portion 23b of the bottom portion 23 as the boundary.

[0060] That is, in the packaging paper 2 folded in two, the sealant layers 13 of the front portion 21 and the back portion 22 face each other (see FIG. 5), and similarly, the sealant layers 13 of the first portion 23a and the second portion 23b of the bottom portion 23 face each other. The base material 11 of each of the front portion 21 and the back portion 22 is located on the outside (see FIG. 5), and similarly, the base material 11 of each of the first portion 23a and the second portion 23b of the bottom portion 23 is located on the outside.

[0061] 7(c), with the first portion 23a and the second portion 23b of the bottom surface portion 23 overlapping each other, a cutout 27 is formed by removing a portion of each of the first portion 23a and the second portion 23b from each of the edges on both sides in the Y direction of the first portion 23a and the second portion 23b. The cutout 27 is formed, for example, by performing a punching process on the first portion 23a and the second portion 23b overlapping each other.

[0062] 7(d), the first portion 23a and the second portion 23b are folded between the front portion 21 and the back portion 22 so that the cutout portions 27 of the first portion 23a and the second portion 23b of the bottom portion 23 face each other and the first portion 23a and the second portion 23b overlap each other. In this step, the base material 11 sides of the first portion 23a and the second portion 23b of the bottom portion 23 face each other. The sealant layer 13 sides of the front portion 21 and the first portion 23a face each other, and the sealant layer 13 sides of the back portion 22 and the second portion 23b face each other.

[0063] Next, with the first portion 23a and the second portion 23b of the bottom portion 23 overlapping each other on both sides of the front portion 21 and the back portion 22 in the Y direction, the sealant layers 13 of the front portion 21 and the first portion 23a are sealed together, and the sealant layers 13 of the back portion 22 and the second portion 23b are sealed together. These sealings are performed by, for example, thermocompression bonding or ultrasonic welding.

[0064] 8(a), this process forms a reinforcing seal portion 25a that seals the sealant layers 13 of the front portion 21 and the first portion 23a together, and also forms a reinforcing seal portion 25b that seals the sealant layers 13 of the back portion 22 and the second portion 23b together. The reinforcing seal portions 25a are formed obliquely from both edge sides of the front portion 21 extending in the X direction toward the lower end 21a of the front portion 21 (the bent portion between the front portion 21 and the first portion 23a of the bottom portion 23; see FIG. 7(d)).

[0065] In addition, the reinforcing seal portion 25b is also formed obliquely from both edge sides extending in the X direction of the back portion 22 toward the lower end 22a of the back portion 22 (the folded portion between the back portion 22 and the second part 23b of the bottom portion 23, see Figure 7(d)).

[0066] Next, the sealant layers 13 are partially sealed together at both edges of the front portion 21 and the back portion 22 in the Y direction, across a double-layered region where the front portion 21 and the back portion 22 overlap, and across a quadruple-layered region where the front portion 21, the back portion 22, and the first portion 23a and the second portion 23b of the bottom portion 23 overlap. This sealing is performed by, for example, thermocompression bonding or ultrasonic welding. This process forms a point seal portion 26 where the sealant layers 13 are sealed together across the double-layered region and the quadruple-layered region, as shown in FIG. 8(b).

[0067] Next, at the edges on both sides in the Y direction of the front portion 21 and the back portion 22, the sealant layers 13 of the front portion 21 and the back portion 22 are sealed to each other, the sealant layers 13 of the first portions 23a of the front portion 21 and the bottom portion 23 are sealed to each other, the sealant layers 13 of the second portions 23b of the back portion 22 and the bottom portion 23 are sealed to each other, and the sealant layers 13 of the front portion 21 and the back portion 22 are sealed to each other through the cut-out portions 27 of the first portions 23a and the second portions 23b. These sealings are performed by, for example, thermocompression bonding or ultrasonic welding.

[0068] By this process, as shown in Figure 8(c), a side seal portion 24 is formed in which the Y-direction edges of the front portion 21 and the back portion 22 are overlapped twice to seal the sealant layers 13 together, and a bottom seal portion 25 is formed in which the Y-direction edges of the first portion 23a and the second portion 23b of the front portion 21, the back portion 22, and the bottom portion 23 are overlapped four times to seal the sealant layers 13 together.

[0069] That is, in step C (second step), the packaging container 10 is formed by sealing the overlapping edges of the sealant layer with the sealant layer facing inward.

[0070] In this way, the packaging container 10 is formed by using the laminate 1 shown in Figure 1, with the sealant layer 13 facing inward, and sealing the sealant layers 13 of the side seal portion 24 and the bottom seal portion 25, which are the adhesive margins, together (i.e., the adhesive margins of the sealant layers).

[0071] After this, the packaging paper 2 on which the side seal portion 24, bottom seal portion 25, reinforcing seal portions 25a, 25b and point seal portion have been formed is cut into a predetermined shape, and a cutout portion 29 is formed in the side seal portion 24, thereby giving the packaging container 10 the shape shown in Figures 2 and 3.

[0072] [Actions and Effects of the Manufacturing Method of the Laminate and Packaging Container of the Embodiment] According to the method for manufacturing a laminate of this embodiment, a two-component adhesive containing a reaction product of a polyol as the base agent and a diisocyanate as the curing agent is used as the adhesive that forms the second adhesive layer 15, and by setting the modulus of elasticity of the second adhesive layer 15 to 2.3 MPa or more, it is possible to manufacture a laminate 1 that can form a packaging container 10 that has a paper substrate 11 but is easy to tear by hand when opened (the sealant layer 13 is prevented from stretching too much). And, according to the method for manufacturing a packaging container of this embodiment, which includes the method for manufacturing a laminate of this embodiment, it is possible to manufacture a packaging container 10 that is easy to tear by hand when opened.

[0073] Furthermore, by using a "two-component adhesive containing a reaction product of a polyol as the main agent and a diisocyanate as the curing agent" as the adhesive that forms the first adhesive layer 14, and making the first adhesive layer 14 relatively hard (with an elastic modulus of 2.3 MPa or more), it is believed that the hand-tearability of the packaging container 10 will also be improved. Therefore, by using a "two-component adhesive containing a reaction product of a polyol as the main agent and a diisocyanate as the curing agent" as the adhesive that forms not only the second adhesive layer 15 but also the first adhesive layer 14, and making the elastic modulus of the first adhesive layer 14 2.3 MPa or more, it is believed that a packaging container 10 with better hand-tearability can be obtained.

[0074] In addition, if the adhesive used to form the first adhesive layer 14 is the same as the adhesive used to form the second adhesive layer 15, the effort required to change the adhesive is eliminated, thereby reducing manufacturing costs. However, the adhesive used to form the first adhesive layer 14 may be different from the adhesive used to form the second adhesive layer 15.

[0075] Furthermore, according to the method for manufacturing a packaging container of this embodiment, it is possible to manufacture a packaging container 10 that can stand on its own stably.

[0076] Furthermore, according to the manufacturing method of the packaging container of this embodiment, the sealant layers 13 of the packaging paper 2 can be sealed together in the side seal portion 24, bottom seal portion 25, reinforcing seal portions 25a, 25b and point seal portion 26, so that a packaging container 10 with excellent sealing properties can be manufactured.

[0077] The laminate 1 of this embodiment comprises a paper substrate 11, an intermediate layer (barrier layer) 12 fixed to one surface of the substrate 11 via a first adhesive layer 14, and a sealant layer 13 fixed to the surface of the intermediate layer 12 opposite the substrate 11 via a second adhesive layer 15. However, the laminate of the present invention may further have other layers, such as a printed layer or a second intermediate layer (an intermediate layer other than the barrier layer), on the entire surface or a part of the laminate.

[0078] Furthermore, the packaging container 10 of this embodiment is formed from only one sheet of packaging paper 2 and can stand on its own with the bottom surface 23 of the packaging paper 2 facing downwards, but the packaging container of the present invention is not limited to this and may be, for example, as shown below.

[0079] In the first example, the front portion 21, the back portion 22, and the bottom portion 23 are formed from different packaging paper, and the front portion 21 and the back portion 22 are made of laminate 1, which is an embodiment of the present invention, but the bottom portion 23 is manufactured using a laminate of a different configuration from laminate 1 (one having a layer that can be sealed with the sealant layer 13 of laminate 1).

[0080] The second example is a packaging container made of two identical sheets of packaging paper, with the edges sealed except for the opening. This packaging container cannot stand on its own.

[0081] The third example is a packaging container that is made of only one strip of packaging paper, and after the packaging paper is folded, the edges of two sides are sealed. This packaging container cannot stand on its own.

[0082] [Another aspect of the present invention] <Second mode> The laminate of the first embodiment, wherein the second adhesive layer comprises the reaction product of a polyol and a curing agent, and the curing agent comprises the reaction product of isophorone diisocyanate.

[0083] When the second adhesive layer contains a reaction product of a polyol and a curing agent that contains a reaction product of isophorone diisocyanate, the adhesive strength between the intermediate layer and the sealant layer can be made higher than when the second adhesive layer contains a reaction product of a polyol and a curing agent that does not contain a reaction product of isophorone diisocyanate.

[0084] <Third mode> A third aspect of the present invention provides a method for producing a laminate including a paper substrate, an intermediate layer fixed to one surface of the substrate via a first adhesive layer, and a sealant layer fixed to the surface of the intermediate layer opposite the substrate via a second adhesive layer, wherein the second adhesive layer is formed using a two-component adhesive containing a reaction product of a polyol as a main agent and a diisocyanate as a curing agent, and the elastic modulus of the second adhesive layer is set to 2.3 MPa or more.

[0085] <Fourth aspect> A fourth aspect of the present invention provides a method for manufacturing a packaging container, comprising: a first step of forming a laminate including a paper substrate, an intermediate layer fixed to one surface of the substrate via a first adhesive layer, and a sealant layer fixed to the surface of the intermediate layer opposite the substrate via a second adhesive layer; and a second step of sealing the overlap edges of the sealant layers of the laminate with the sealant layers facing inward, wherein in the first step, a two-component adhesive containing a reaction product of a polyol as a main agent and a diisocyanate as a curing agent is used as the adhesive for forming the second adhesive layer, and the elastic modulus of the second adhesive layer is set to 2.3 MPa or more. [Example]

[0086] The present invention will be described in detail below with reference to specific examples. The substrate 11 of the laminate 1 has a thickness of about 90 μm and a basis weight of 60 g / m 2, 80g / m 2 , 120g / m 2 A paper substrate having the above structure was prepared. As the intermediate layer 12, a barrier film (transparent barrier film "GL-ARH-F" manufactured by Toppan Printing Co., Ltd.) having a thickness of 12 μm and a vapor-deposited inorganic material film as a barrier coating layer on a PET film was prepared. As the sealant layer 13, a non-oriented polypropylene film (CPP film) having a thickness of 50 μm was prepared.

[0087] The following were prepared as the base agent and curing agent for the two-component adhesive. Main ingredient Main component 1: Polyester polyol, "Takelac (registered trademark) A-626" manufactured by Mitsui Chemicals, Inc. Base agent 2: Mixture of polyester polyol and polyurethane polyol (1), "Takelac (registered trademark) A-525" manufactured by Mitsui Chemicals, Inc. Main component 3: a mixture of polyester polyol and polyurethane polyol (2), "DIC Dry (registered trademark) LX500" manufactured by DIC Graphics Corporation

[0088] Hardener IPDI (1): "Takenate (registered trademark) A-52" manufactured by Mitsui Chemicals, Inc. The main component is a reaction product of isophorone diisocyanate, and also contains a reaction product of XDI (xylylene diisocyanate). IPDI (2): "Takenate (registered trademark) A-50" manufactured by Mitsui Chemicals, Inc. The main component is a reaction product of isophorone diisocyanate, and also contains a reaction product of XDI (xylylene diisocyanate).

[0089] HDI (1): "Takenate (registered trademark) A-65" manufactured by Mitsui Chemicals, Inc. The main component is a reaction product of hexamethylene diisocyanate. HDI (2): "KR90S" manufactured by DIC Graphics Corporation. The main component is a reaction product of hexamethylene diisocyanate.

[0090] [No.1] [Measurement of adhesive strength] For sample No. 1, an adhesive was used in which base agent 1 and IPDI (1) were mixed in a mass ratio of base agent 1:IPDI (1) = 8:1, and the basis weight was 80 g / m 2 The adhesive strength between the substrate 11 and the intermediate layer 12 and the adhesive strength between the intermediate layer 12 and the sealant layer 13 were measured.

[0091] Specifically, the substrate 11, intermediate layer 12, and sealant layer 13 were each cut into test pieces (15 mm wide) for a T-peel test, and the adhesive was applied between the test piece of the substrate 11 and the test piece of the intermediate layer 12 in an amount of 3.3 g / m 2 The test pieces were bonded together under the same pressure as in the dry lamination process used to prepare Laminate 1. Using the resulting test piece (substrate / intermediate layer), a T-peel test was performed at a temperature of 24°C and a tensile speed of 300 mm / min.

[0092] The adhesive was applied between the test piece of the intermediate layer 12 and the test piece of the sealant layer 13 in an amount of 3.3 g / m 2 The test pieces were bonded together under the same pressure as in the dry lamination process used to prepare Laminate 1. Using the resulting test piece (intermediate layer / sealant layer), a T-peel test was performed at a temperature of 24°C and a tensile speed of 300 mm / min.

[0093] [Measurement of Elastic Modulus of Second Adhesive Layer] (Preparation of test specimens) Next, the same adhesive was applied to the substrate 11 in an amount of 3.3 g / m 2 The adhesive was applied in the same amount to the intermediate layer 12 side of the obtained laminate, and a sealant layer 13 was laminated to obtain a laminate 1. The obtained laminate 1 was cut into a shape for a test piece for measuring the elastic modulus.

[0094] The front and back surfaces of the cut-out laminate 1 were each subjected to a corona treatment at 0.20 kW (apparatus: corona treatment machine CT-0212 manufactured by Kasuga Denki Co., Ltd.), and then the laminate 1 was cut with a razor into a wedge shape with a base of 1.0 mm and a height of 5.0 mm. The cut laminate 1 was embedded in a photocurable resin, which was a D-800 photocurable resin manufactured by Toagosei Co., Ltd., and cured using a halogen lamp KTX-100R (manufactured by Kenko Tokina Co., Ltd.).

[0095] Next, the embedded laminate 1 was fixed in an insert for an AFM sample holder, and the cross section of the film was cut with a glass knife at room temperature (25°C). After that, final cross section cutting was performed with a diamond knife at room temperature at a cutting speed of 1.0 mm / s and a cutting layer thickness of 100 nm, and cutting was completed when a mirror surface was obtained.

[0096] An ultramicrotome (Leica EM UC7) and a cryosystem (Leica EM FC7) were used as cross-section cutting devices. The cutting direction of the knife was parallel to the layer interface. In this way, the second adhesive layer 15 was exposed, and a test piece was obtained.

[0097] (Measurement of elastic modulus) Next, the modulus of elasticity of the obtained test piece was measured at 300 points on the cross section of the second adhesive layer 15 by the following method, and the average value of the 300 measured values ​​was calculated. The modulus of elasticity shown in Table 1 is the value (average value).

[0098] <Measurement method> For each test piece, a force curve was measured at one location (one of the 300 locations described below) on the cross section of the second adhesive layer using an atomic force microscope (AFM), and a graph was obtained showing the relationship between the deformation of the second adhesive layer and the load applied to each location on the second adhesive layer. From each graph obtained, the elastic modulus of the second adhesive layer at that location was calculated based on the JKR analysis model. The measurement device, measurement conditions, and analysis conditions were as follows.

[0099] The measurements of the 300 locations were performed by setting three 1 μm x 1 μm square areas in the measurement field of view on the cross section of the second adhesive layer 15, with the center of the thickness direction of the second adhesive layer 15 as the midpoint, and measuring 100 locations in each area.

[0100] <Device> Atomic force microscope (AFM) "MFP-3D (Oxford Instruments)"

[0101] <Cantilever> Model number: Biosphere B50-FM (Nanotools) Tip material: Diamond-like carbon Radius of curvature: 50nm

[0102] <Measurement conditions> Maximum load: 5nN (test depth is 20-30nm) Test speed: 500nm / sec

[0103] <Analysis conditions> Analysis model: JKR model Analysis domain: Pull-out domain Analysis range: Load 0 to 80% (percentage of minimum to maximum value) Poisson's ratio of sample: 0.33

[0104] [Evaluation of hand tearing performance] Next, the obtained laminate 1 was cut out to obtain the packaging paper 2 shown in Fig. 7(a), and three packaging containers 10 were obtained by the method described in the embodiment. The hand-tearability of the obtained three packaging containers 10 was examined by the following method.

[0105] (Method for evaluating hand tearing performance) The resulting packaging container 10 was cut with a cutter before and after retorting, and the ease of tearing when torn by hand was examined in the MD direction and evaluated as follows. The retort treatment was carried out by sealing water in the resulting packaging container 10 and heating it in a hot water storage system at 120°C for 30 minutes. The post-retort measurement was carried out 120 minutes after the retort treatment.

[0106] 〇: No snags and cuts smoothly. △: There are parts that cut smoothly and parts that catch. ×: The sealant layer is stretched too much and cannot be torn off easily.

[0107] Furthermore, samples that did not receive an "x" rating in at least either the MD or TD direction were evaluated as "pass" having the desired performance, and the others were evaluated as "fail" not having the desired performance.

[0108] [No.2] For sample No. 2, first, an adhesive was used in which base agent 1 and IPDI (2) were mixed in a mass ratio of base agent 1:IPDI (1) = 8:1, and a grammage of 80 g / m was applied in the same manner as No. 1. 2 The adhesive strength between the substrate 11 and the intermediate layer 12 and the adhesive strength between the intermediate layer 12 and the sealant layer 13 were measured.

[0109] Next, using this adhesive, three packaging containers 10 were produced using the obtained laminate 1 in the same manner as in No. 1, and the hand-tearability of the three obtained packaging containers 10 was examined in the same manner as in No. 1.

[0110] [No.3] For sample No. 3, first, an adhesive was used in which base agent 2 and IPDI (1) were mixed in a mass ratio of base agent 2:IPDI (1) = 9:1, and a grammage of 80 g / m was applied in the same manner as No. 1. 2 The adhesive strength between the substrate 11 and the intermediate layer 12 and the adhesive strength between the intermediate layer 12 and the sealant layer 13 were measured.

[0111] Next, using this adhesive, three packaging containers 10 were produced using the obtained laminate 1 in the same manner as in No. 1, and the hand-tearability of the three obtained packaging containers 10 was examined in the same manner as in No. 1.

[0112] [No.4] Sample No. 4 has a basis weight of 60 g / m 2 The adhesive strength between the substrate 11 and the intermediate layer 12 and the adhesive strength between the intermediate layer 12 and the sealant layer 13 were measured in the same manner as in No. 1, except that the substrate 11 of No. 1 was used.

[0113] Next, using this adhesive, three packaging containers 10 were produced using the obtained laminate 1 in the same manner as in No. 1, and the hand-tearability of the three obtained packaging containers 10 was examined in the same manner as in No. 1.

[0114] [No.5] Sample No. 5 has a basis weight of 100 g / m 2 The adhesive strength between the substrate 11 and the intermediate layer 12 and the adhesive strength between the intermediate layer 12 and the sealant layer 13 were measured in the same manner as in No. 1, except that the substrate 11 of No. 1 was used.

[0115] Next, using this adhesive, three packaging containers 10 were produced using the obtained laminate 1 in the same manner as in No. 1, and the hand-tearability of the three obtained packaging containers 10 was examined in the same manner as in No. 1.

[0116] [No.6] For sample No. 6, first, an adhesive was used in which main component 1 and HDI (1) were blended in a mass ratio of main component 1:HDI (1) = 16:1, and the adhesive strength between the substrate 11 and intermediate layer 12 and the adhesive strength between the intermediate layer 12 and sealant layer 13 were measured using the same method as for No. 1.

[0117] Next, using this adhesive, three packaging containers 10 were produced using the obtained laminate 1 in the same manner as in No. 1, and the hand-tearability of the three obtained packaging containers 10 was examined in the same manner as in No. 1.

[0118] [No.7] For sample No. 7, an adhesive was used in which main component 3 and HDI (2) were blended in a mass ratio of main component 3:HDI (2) = 15:1, and the adhesive strength between the substrate 11 and intermediate layer 12 and the adhesive strength between the intermediate layer 12 and sealant layer 13 were measured using the same method as for No. 1.

[0119] Next, using this adhesive, three packaging containers 10 were produced using the obtained laminate 1 in the same manner as in No. 1, and the hand-tearability of the three obtained packaging containers 10 was examined in the same manner as in No. 1.

[0120] Table 1 shows the structure and modulus of elasticity of the second adhesive layer, the weight of the substrate, adhesive strength, and hand tearability of Samples No. 1 to No. 7.

[0121] [Table 1]

[0122] As can be seen from the results in Table 1, among Nos. 1 to 5 and No. 7, which correspond to examples of the present invention, Nos. 1, 2, 4, and 5 had sufficient adhesive strength between the "substrate / intermediate layer" and the "intermediate layer / sealant layer," and all three specimens were rated "Good" for hand-tearability in the MD direction. No. 3 also had sufficient adhesive strength between the "substrate / intermediate layer" and the "intermediate layer / sealant layer," and all three specimens were rated "Good" for hand-tearability in the MD direction. This difference is thought to be due to the difference in the type of base resin. No. 7's hand-tearability in the MD direction was "Good." Furthermore, based on the above-mentioned pass / fail evaluation criteria, Nos. 1 to 5 and No. 7, which correspond to examples of the present invention, were rated "Good" for the desired performance.

[0123] In contrast, No. 6, which corresponds to a comparative example of the present invention, had hand-tearability in the MD evaluated as "x." Therefore, based on the above-mentioned pass / fail evaluation criteria, No. 6, which corresponds to a comparative example of the present invention, was evaluated as "fail" because it did not have the desired performance.

[0124] As can be seen from the above, by bonding the intermediate layer 12 and the sealant layer 13 using the adhesive used in Nos. 1 to 5 and 7, a laminate 1 having a second adhesive layer 15 with an elastic modulus of 2.3 MPa or more can be used to manufacture a packaging container that is easy to tear by hand when opening. Furthermore, in Nos. 1 to 5 and 7, which correspond to examples of the present invention, a laminate 1 having a higher adhesive strength between the "intermediate layer / sealant layer" can be manufactured using the adhesive used in Nos. 1 to 5 than when the adhesive used in No. 7 is used. [Explanation of symbols]

[0125] 1. Laminate 2 Packaging paper 10 Packaging containers 11 Base material 14 First adhesive layer 12 Middle Class 13 Sealant layer 15 Second adhesive layer 24 Side seal (glue) 25 Bottom seal (glue)

Claims

1. The present invention comprises a paper substrate, an intermediate layer fixed to one surface of the substrate via a first adhesive layer, and a sealant layer fixed to a surface of the intermediate layer opposite to the substrate via a second adhesive layer, A laminate in which the second adhesive layer has an elastic modulus of 2.3 MPa or more.

2. 10. The laminate of claim 1, wherein the second adhesive layer comprises the reaction product of a polyol and a curing agent, the curing agent comprising the reaction product of a diisocyanate.

3. 10. The laminate of claim 1, wherein said second adhesive layer comprises the reaction product of a polyol and a curing agent, said curing agent comprising the reaction product of isophorone diisocyanate.

4. A packaging container comprising the laminate according to any one of claims 1 to 3, wherein the sealant layer is placed on the inside and the overlaps of the sealant layer are sealed together.

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