Packaging bag and manufacturing method of the same

Abstract

To provide a manufacturing method of a packaging bag which can store an article used in a clean environment, and which has high cleanliness.SOLUTION: A manufacturing method of a packaging bag includes the steps of: forming a tube-like film which at least includes a first resin layer constituting a tube outer surface and a second resin layer constituting a tube inner surface by the co-extrusion inflation technique, and deforming the film into a flat shape; and performing bag-making operation without releasing the contact between the second resin layers opposing each other and in contact with each other, with respect to the tube-like film and the like deformed into a flat surface, and manufacturing a packaging bag. The packaging bag includes: a front surface sheet; and a rear surface sheet opposing the front surface sheet. Each of the front surface sheet and the rear surface sheet at least includes a first resin layer and a second resin layer constituting the inner surface of the packaging bag. In the front surface sheet and the rear surface sheet, the first resin layer is provided so as to be peelable from the second resin layer.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present disclosure relates to a packaging bag and a method for manufacturing the same. [Background technology]

[0002] Semiconductor products are manufactured or used in clean environments such as clean rooms with high levels of cleanliness, because the quality of the products can be reduced if foreign matter such as dust and dirt adheres to the products. When an article is brought into such an environment, a package in which the article is contained in a bag made of plastic film is often brought into the clean environment. Therefore, high cleanliness is also required for packaging bags that contain articles that require a high level of cleanliness, such as semiconductor products.

[0003] Conventionally, a package is manufactured as follows using a double bag having at least an inner bag and an outer bag (see, for example, Patent Document 1). First, an item is placed inside the inner bag, which is vacuum degassed, and the opening of the inner bag is sealed. Next, the inner bag is placed inside the outer bag, which is vacuum degassed, and the opening of the outer bag is sealed. The item is packaged in this double packaging, or triple packaging as necessary. When the item is to be used, the outer bag is opened in the antechamber of the clean room, the clean inner bag is opened inside the clean room, and the item is removed. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] JP 2012-126437 A Summary of the Invention [Problem to be solved by the invention]

[0005] When packaging an article using double or triple vacuum packaging, the vacuum packaging is performed multiple times. This can result in low work efficiency for packaging the article. In addition, when opening the packaging bag, opening the bag multiple times can be a hassle.

[0006] An object of the present disclosure is to provide a packaging bag that can contain items used in a clean environment and has a high level of cleanliness, and a manufacturing method thereof. [Means for solving the problem]

[0007] The present inventors have investigated the production of a packaging bag using a laminate having a peelable surface film. By peeling off the surface film of the packaging bag in the antechamber of the clean room, the packaging bag in a clean state can be brought into the clean room. Based on this knowledge, the present inventors have found that the above-mentioned problems can be solved by a packaging bag having the following configuration and a manufacturing method thereof. A method for manufacturing a packaging bag according to one embodiment of the present disclosure includes the steps of forming a tubular film by a coextrusion inflation method, the tubular film having at least a first resin layer that constitutes the outer surface of the tube and a second resin layer that contains polyolefin as a main component and constitutes the inner surface of the tube, and deforming the film into a flat shape, and performing a bag-making process on the flattened tubular film or a laminated film obtained by cutting the film, without releasing the contact between the second resin layers that are in contact with each other and producing a packaging bag, the packaging bag having a top sheet and a back sheet facing the top sheet, the top sheet and the back sheet each having at least the first resin layer and the second resin layer that constitutes the inner surface of the packaging bag, the first resin layer in the top sheet and the back sheet being arranged so as to be peelable from the second resin layer, and the packaging bag having a seal portion formed by joining a part of the second resin layer in the top sheet and a part of the second resin layer in the back sheet. A packaging bag according to one embodiment of the present disclosure comprises a top sheet and a back sheet opposed to the top sheet, each of which comprises at least a first resin layer and a second resin layer constituting the inner surface of the packaging bag, the second resin layer containing polyolefin as a main component, and the first resin layer in the top sheet and back sheet is provided so as to be peelable from the second resin layer, the packaging bag has a seal portion formed by joining a part of the second resin layer in the top sheet and a part of the second resin layer in the back sheet, and the packaging bag is made by directly manufacturing a bag from a film obtained by deforming a tubular film produced by a coextrusion inflation method into a flat shape, the film comprising at least a first resin layer constituting the outer surface of a tube and a second resin layer constituting the inner surface of the tube, or from a laminated film obtained by cutting the film. Effect of the Invention

[0008] According to the present disclosure, it is possible to provide a packaging bag capable of containing items to be used in a clean environment and having a high level of cleanliness, and a method for manufacturing the same. [Brief description of the drawings]

[0009] [Figure 1] FIG. 1 is a schematic cross-sectional view of one embodiment of a packaging bag and its related drawings. [Diagram 2] FIG. 2 is a front view of one embodiment of a packaging bag. [Diagram 3] FIG. 3 is a schematic diagram illustrating the half-cut line. [Figure 4] FIG. 4 is a front view for explaining the production of a packaging bag. [Diagram 5] FIG. 5 is a schematic cross-sectional view of one embodiment of a laminate. [Figure 6] FIG. 6 is a schematic cross-sectional view of one embodiment of a laminate. [Figure 7] FIG. 7 is a schematic cross-sectional view of one embodiment of a laminate. [Figure 8] FIG. 8 is a schematic cross-sectional view of one embodiment of a laminate. [Figure 9]FIG. 9 is a schematic cross-sectional view of one embodiment of a laminate. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0010] Hereinafter, the embodiments of the present disclosure will be described in detail. The present disclosure can be implemented in many different forms, and is not to be interpreted as being limited to the description of the embodiments exemplified below. In the drawings, the width, thickness, shape, etc. of each layer may be shown diagrammatically in order to make the explanation clearer, but these are merely examples and do not limit the interpretation of the present disclosure. In this specification and each figure, elements similar to those already explained with respect to the previous figures are given the same reference numerals, and detailed explanations may be omitted as appropriate.

[0011] In the present disclosure, when multiple upper limit candidates and multiple lower limit candidates are listed for a certain parameter, the numerical range of the parameter may be configured by combining any one upper limit candidate and any one lower limit candidate. Examples of the above parameters include physical property values, component content ratios, and layer thicknesses. As an example, the description "Parameter B is preferably A1 or more, more preferably A2 or more, and even more preferably A3 or more. Parameter B is preferably A4 or less, more preferably A5 or less, and even more preferably A6 or less." will be explained. In this example, the numerical range of parameter B may be A1 or more and A4 or less, A1 or more and A5 or less, A1 or more and A6 or less, A2 or more and A4 or less, A2 or more and A5 or less, A2 or more and A6 or less, A3 or more and A4 or less, A3 or more and A5 or less, or A3 or more and A6 or less.

[0012] In the following description of this specification, each of the components (e.g., polyolefins such as polyethylene and polypropylene, α-olefins, resin materials such as heteroatom-containing resins, and additives) that appear may be used alone or in combination of two or more kinds.

[0013] In this specification, polyethylene refers to a polymer in which the content of ethylene-derived structural units in all repeating structural units exceeds 50 mol%. In this polymer, the content of ethylene-derived structural units is preferably 70 mol% or more, more preferably 80 mol% or more, even more preferably 90 mol% or more, and particularly preferably 95 mol% or more. The content is measured by NMR.

[0014] In this specification, polyethylene may be a homopolymer of ethylene, or a copolymer of ethylene and an ethylenically unsaturated monomer other than ethylene. Examples of the ethylenically unsaturated monomer other than ethylene include α-olefins having 3 to 20 carbon atoms, such as propylene, 1-butene, 1-pentene, 1-hexene, 1-octene, 1-decene, 1-dodecene, 1-tetradecene, 1-hexadecene, 1-octadecene, 1-eicosene, 3-methyl-1-butene, 4-methyl-1-pentene, and 6-methyl-1-heptene, vinyl monomers such as vinyl acetate and vinyl propionate, and (meth)acrylic acid esters such as methyl (meth)acrylate and ethyl (meth)acrylate.

[0015] In this specification, polyethylene includes, for example, high density polyethylene, medium density polyethylene, low density polyethylene and linear low density polyethylene, as well as ethylene-vinyl acetate copolymer and ethylene-(meth)acrylic acid ester copolymer.

[0016] In this specification, the density of polyethylene is as follows: The density of the high density polyethylene is preferably 0.945 g / cm 3 The density of the high density polyethylene is preferably greater than 0.965 g / cm 3 The density of the medium density polyethylene is preferably 0.932 g / cm 3 Exceeds 0.945g / cm 3 The density of the low density polyethylene is preferably 0.860 g / cm 3 More than 0.932g / cm 3Less than or equal to 0.900 g / cm 3 More than 0.932g / cm 3 The density of the linear low density polyethylene is preferably 0.860 g / cm 3 More than 0.932g / cm 3 Less than or equal to 0.900 g / cm 3 More than 0.932g / cm 3 The density of polyethylene is measured in accordance with JIS K7112:1999, Method D (density gradient tube method, 23°C).

[0017] Low-density polyethylene is, for example, polyethylene obtained by polymerizing ethylene by high-pressure polymerization (high-pressure low-density polyethylene). Linear low-density polyethylene is, for example, polyethylene obtained by polymerizing ethylene and a small amount of α-olefins by a polymerization method using a multi-site catalyst such as a Ziegler-Natta catalyst or a single-site catalyst such as a metallocene catalyst.

[0018] Polyethylenes with different densities or branches can be obtained by appropriately selecting a polymerization method. For example, it is preferable to carry out polymerization in one or more stages by using a multi-site catalyst such as a Ziegler-Natta catalyst or a single-site catalyst such as a metallocene catalyst as a polymerization catalyst, by any of gas phase polymerization, slurry polymerization, solution polymerization, and high pressure ion polymerization.

[0019] As the polyethylene, polyethylene derived from biomass (hereinafter also referred to as "biomass polyethylene") may be used. That is, as a raw material for obtaining polyethylene, ethylene derived from biomass may be used instead of ethylene obtained from fossil fuels. Since biomass polyethylene is a carbon-neutral material, it is possible to reduce the environmental load caused by packaging bags. Biomass polyethylene can be produced, for example, by the method described in JP 2013-177531 A. Commercially available biomass polyethylene may be used.

[0020] The polyethylene may be mechanically recycled or chemically recycled. This reduces the environmental impact of packaging bags. Mechanical recycling is generally a method in which collected polyethylene films are crushed, washed with an alkali to remove dirt and foreign matter from the film surface, and then dried at high temperature and reduced pressure for a certain period of time to diffuse contaminants remaining inside the film, decontaminating it, removing the dirt from the film, and returning it to polyethylene. Chemical recycling is generally a method in which collected polyethylene films are decomposed to the monomer level, and the monomers are polymerized again to obtain polyethylene.

[0021] In this specification, the "main component" of a certain layer refers to a component whose content in the layer is more than 50% by mass, preferably 60% by mass or more, more preferably 70% by mass or more, and even more preferably 80% by mass or more.

[0022] In this specification, terms such as "film" and "sheet" are not distinguished from each other solely on the basis of differences in name.

[0023] [Packaging bags and their manufacturing methods] The packaging bag of the present disclosure includes a top sheet and a back sheet facing the top sheet. The top sheet constitutes the front surface of the packaging bag. The back sheet constitutes the back surface of the packaging bag. The terms "top surface" and "back surface" in the above sheets merely represent the top surface and back surface of the packaging bag relatively. The posture of the packaging bag during transportation or use is not limited by the top surface and back surface in this specification.

[0024] The top sheet and the back sheet each include at least a first resin layer and a second resin layer that constitutes the inner surface of the packaging bag. In one embodiment, the first resin layer constitutes the outer surface of the packaging bag. The second resin layer constitutes the inner surface facing the storage space of the packaging bag (the surface that comes into contact with the item inside the packaging bag). In the top sheet and the back sheet, the first resin layer is provided so as to be peelable from the second resin layer.

[0025] The top sheet and the back sheet are each derived from the same tubular film produced by a coextrusion inflation method. The tubular film has at least a first resin layer constituting the outer surface of the tube and a second resin layer constituting the inner surface of the tube. As described below, the inner surface is highly clean because it is prevented from coming into contact with the outside air during the production of the tubular film and the packaging bag.

[0026] The second resin layer has a first surface and a second surface opposite to the first surface. The first resin layer is provided on the first surface of the second resin layer. The first resin layer is in contact with the second resin layer, specifically, in contact with the first surface of the second resin layer. Therefore, the first surface of the second resin layer is usually a peeling surface when peeling off the first resin layer.

[0027] The number of particles having a particle diameter of 0.2 μm or more attached to the inner surface of the packaging bag of the present disclosure is preferably 100 particles / cm 2 Less than or equal to 80 particles / cm 2 Less than 60 / cm, more preferably 2 Less than 40 / cm, and even more preferably 2 Less than 20 / cm is particularly preferable. 2 Below, 15 pieces / cm 2 Below, 10 pieces / cm 2 Less than or equal to 5 pieces / cm 2 The lower limit of the number of particles is not particularly limited, but is, for example, 0.1 particles / cm 2 Even 0.5 pieces / cm is fine. 2 Even 1 piece / cm 2 The number of particles is measured using a particle counter. Details of the measurement method are described in the Examples section. By producing a packaging bag by the manufacturing method described below, the number of particles adhering to the inner surface of the packaging bag can be reduced.

[0028] The packaging bag has a sealed portion formed by joining (e.g., fusing) a part of the second resin layer on the top sheet and a part of the second resin layer on the back sheet. The sealed portion is usually a heat-sealed portion.

[0029] 1a is a cross-sectional view showing one embodiment of a packaging bag of the present disclosure. The packaging bag 50 includes a top sheet 54 and a back sheet 55. The top sheet 54 includes a first resin layer 10 and a second resin layer 20. The back sheet 55 includes a first resin layer 10 and a second resin layer 20. The packaging bag 50 has a seal portion HS formed by joining a part of the second resin layer 20 in the top sheet 54 and a part of the second resin layer 20 in the back sheet 55.

[0030] The packaging bag 50 is formed, for example, as follows. As shown in Figure 1b, the co-extrusion inflation method is used to form the outer surface of the tube S out The first resin layer 10 constituting the tube inner surface S in A tubular film 2 including at least the second resin layer 20 constituting the tubular film 2 is formed, and the film 2 is deformed into a flat shape (specifically, folded). Next, as shown in FIG. 1c, parts of the second resin layer 20 facing each other in the tubular film 2 are joined together to form a sealed portion HS. In FIG. 1c, in order to make the figure easier to see, the tubular film 2 is not deformed into a flat shape. Next, both ends of the heat-sealed tubular film 2 are cut off to a predetermined width. Note that the sealed portion HS may be formed after this cutting. Next, a predetermined cutting process is performed. In this way, a packaging bag 50 is obtained. In this way, the packaging bag 50 is obtained by directly making a bag from the tubular film 2 deformed into a flat shape or the overlapped film obtained by cutting the film. The details of the manufacturing method of the packaging bag 50 will be described later. "A packaging bag obtained by directly manufacturing a flattened tubular film or a laminated film obtained by cutting the film" means a packaging bag obtained by forming a seal part and cutting the film on a flattened tubular film or a laminated film obtained by cutting the film, without releasing the contact between the second resin layers that are in contact with each other. Here, the tubular film may be cut, for example, along the flow direction of the film before the seal part is formed, but the laminated film after the cut is subjected to a bag-making process without releasing the contact between the second resin layers. "Without releasing the contact between the second resin layers facing each other" means, in the case of a flattened tubular film, maintaining the flattened state without introducing outside air into the tube, and in the case of a superposed film, maintaining the superposed state of both films without separating the superposed films from each other by cutting the tubular film. As long as the purpose of the present disclosure is not impaired, the second resin layers facing each other may not be in contact with each other in a small area.

[0031] 1d is a cross-sectional view showing one embodiment of a usage form of the packaging bag of the present disclosure. For example, the first resin layers 10, 10 are peeled off from the second resin layers 20, 20 of the packaging bag 50, respectively, immediately before being brought into a clean room.

[0032] Examples of packaging bags include packaging bags of various shapes such as a standing pouch type, a side seal type, a two-sided seal type, a three-sided seal type, a four-sided seal type, an envelope seal type, a grooving seal type (pillow seal type), a pleated seal type, a flat bottom seal type, a square bottom seal type, and a gusset type. The planar shape of the packaging bag may be, for example, rectangular or a shape other than rectangular, such as a circle.

[0033] The packaging bag may have an easy-open portion. Examples of the easy-open portion include a notch portion that serves as a starting point for tearing the packaging bag, and an easy-open line formed by laser processing or a cutter as a path for tearing the packaging bag.

[0034] FIG. 2 is a front view showing one embodiment of the packaging bag of the present disclosure. Hereinafter, an example of the packaging bag will be described with reference to FIG. 2. The packaging bag 50 in FIG. 2 has a storage section 50a for storing an item. The packaging bag 50 includes an upper section 51, a lower section 52, and side sections 53, 53, and has a substantially rectangular outline in a front view. Note that names such as "upper section," "lower section," and "side section," as well as terms such as "upper" and "lower" merely relatively indicate the positions and directions of the packaging bag 50 and its components. The posture, etc. of the packaging bag 50 during transportation or use are not limited by the names and terms in this specification.

[0035] As shown in Fig. 2, the packaging bag 50 includes a top sheet 54 constituting the top surface and a back sheet 55 constituting the back surface. In the packaging bag 50 shown in Fig. 2, the top sheet 54 and the back sheet 55 are each formed from the same tubular film produced by a coextrusion inflation method.

[0036] The inner surfaces of the top sheet 54 and the back sheet 55 are joined at a sealed portion. In the front view of the packaging bag 50 shown in Fig. 2, the sealed portion is hatched. The sealed portion is the portion where the second resin layers are joined together.

[0037] 2, the packaging bag 50 has a seal portion extending along the four sides of the packaging bag 50. The seal portion includes an upper seal portion 51a extending along the upper portion 51, a pair of side seal portions 53a, 53a extending along a pair of side portions 53, 53, and a lower seal portion 52a extending along the lower portion 52. In the packaging bag 50 in a state before an article is contained therein (a state in which no article is contained therein), an opening (not shown) is formed in the upper portion 51 of the packaging bag 50. After an article is contained in the packaging bag 50, the inner surface of the top sheet 54 and the inner surface of the back sheet 55 are joined at the upper portion 51 to form the upper seal portion 51a and seal the packaging bag 50.

[0038] The upper seal portion 51a, the side seal portions 53a, 53a and the lower seal portion 52a are seal portions formed by joining the inner surface of the top sheet 54 and the inner surface of the back sheet 55 together.

[0039] There is no particular limitation on the method for forming the sealed portion as long as it is possible to join opposing sheets 54, 55 together to seal packaging bag 50. For example, the sealed portion is formed by melting the inner surfaces of the sheets by heating or the like and fusing the inner surfaces together, that is, by heat sealing.

[0040] In one embodiment, the top sheet and / or the back sheet constituting the packaging bag have a half-cut line. The half-cut line is a cut line that extends from the surface of the first resin layer constituting the sheet to the interface between the first resin layer and the second resin layer, but does not penetrate the sheet. Starting from the half-cut line, the first resin layer of the sheet can be easily peeled off and removed by hand.

[0041] The position where the half-cut line is formed is not particularly limited. For example, in the case of a packaging bag having a rectangular planar shape, it is preferable to provide the half-cut line at at least one corner of the packaging bag. The half-cut line is preferably formed on both the top sheet and the back sheet of the packaging bag. In one embodiment, the half-cut line extends from the side outer edge of the top sheet and the back sheet to the lower outer edge at the corner of the sheet. The half-cut line can be formed, for example, by mechanically cutting the sheet in the thickness direction using a cutter or the like, or by irradiating the sheet with a laser.

[0042] The half cut line will be specifically described with reference to FIG. 2 and FIG. As shown in Fig. 2, a half-cut line 60 is formed at one corner of the sealed portion of packaging bag 50. As shown in Fig. 2, half-cut line 60 extends from the outer edge of side portion 53 to the outer edge of lower portion 52 of packaging bag 50. Half-cut line 60 is formed on both the front and back surfaces of packaging bag 50, i.e., on top sheet 54 and back sheet 55. FIG. 3 is an enlarged view of a half-cut line provided on the sheet constituting the packaging bag.

[0043] Since half-cut lines 60 are formed on both the front and back sides of the packaging bag 50, a corner of the packaging bag 50 can be folded along the half-cut line 60 formed on one side just before the packaging bag 50 containing an article is brought into a clean room. This allows the first resin layer 10 to be easily peeled off from the second resin layer 20. Next, the other first resin layer 10 can be peeled off from the second resin layer 20 by similarly folding a corner of the packaging bag 50 along the half-cut line 60 formed on the other side.

[0044] From the viewpoint of the strength and heat resistance of the packaging bag, the thickness of the top sheet and the back sheet is preferably 15 μm or more, more preferably 20 μm or more, even more preferably 30 μm or more, still more preferably 40 μm or more, and particularly preferably 50 μm or more. From the viewpoint of the processability of the packaging bag, the thickness of the top sheet and the back sheet is preferably 300 μm or less, more preferably 250 μm or less, even more preferably 200 μm or less, still more preferably 150 μm or less, and particularly preferably 100 μm or less.

[0045] From the viewpoint of heat sealability, the top sheet and the back sheet are preferably unstretched films. The term "unstretched film" refers not only to a film that is not stretched at all, but also to a film that is stretched due to tension applied during film formation by a coextrusion inflation method.

[0046] In one embodiment, the content of polyolefin-based resin in the top sheet and the back sheet may be 70% by mass or more, 75% by mass or more, 80% by mass or more, 85% by mass or more, or 90% by mass or more, based on the mass of the sheets. Such a packaging bag has excellent recyclability. The content of polyolefin-based resin in the top sheet and the back sheet may be 99% by mass or less, 95% by mass or less, or 90% by mass or less, based on the mass of the sheets. The above "content of polyolefin-based resin" can be read as "content of polyethylene-based resin" or "content of polypropylene-based resin".

[0047] The method for producing a packaging bag according to the present disclosure includes: A process of forming a tubular film having at least a first resin layer constituting an outer surface of the tube and a second resin layer constituting an inner surface of the tube, the second resin layer containing polyolefin as a main component, by a coextrusion inflation method, and deforming the film into a flat shape (hereinafter also referred to as "process (1)"); a step of subjecting the tubular film deformed into a flat shape or the overlapped film obtained by cutting the film to a bag-making process without releasing the contact between the second resin layers that are in contact with each other and face to face, thereby producing a packaging bag (hereinafter also referred to as "step (2)"); Includes.

[0048] The manufacturing method of the present disclosure can produce the packaging bag of the present disclosure described above.

[0049] <Process (1)> In step (1), a tubular film is formed by a co-extrusion inflation method, the tubular film having at least a first resin layer that forms the outer surface of the tube and a second resin layer that forms the inner surface of the tube and contains polyolefin as its main component, and the film is deformed into a flat shape (specifically, folded).

[0050] Examples of the melt extruder used in the co-extrusion inflation method include a single screw extruder, a twin screw extruder, a vent extruder, and a tandem extruder. Since the packaging bag has a multi-layer structure, a multi-layer annular die and multiple melt extruders are used. The co-extrusion inflation method includes an air-cooled inflation method and a water-cooled inflation method. Since the film production speed is fast and a wide film can be produced, the air-cooled inflation method is preferred, and the upward air-cooled inflation method is more preferred.

[0051] One embodiment of the coextrusion blown film process is described below. First, the materials constituting each layer are fed to an extruder, melted, and extruded into a tube shape through a multi-layer annular die. At this time, air is fed from below into the inside of the tubular molten resin to expand the diameter of the tube to a predetermined size, and cooling air is fed from the outside of the tube to form a tubular film. Next, while the obtained tubular film is pulled up by a pinch roll, it is deformed into a flat shape by a stabilizer and a pinch roll. At this time, the inner surfaces facing each other in the tubular film, i.e., the facing second resin layers, are in contact with each other. If desired, the flattened tubular film is wound up in the winding section to obtain a rolled body.

[0052] According to the co-extrusion inflation method, a tubular film having a first resin layer and a second resin layer laminated thereon can be easily produced in one step. Here, the first resin layer is provided so as to be peelable from the second resin layer after bag making, as described later.

[0053] <Process (2)> In step (2), the tubular film deformed into a flat shape in step (1) or the overlapping films obtained by cutting the film are subjected to a bag-making process without releasing the contact between the second resin layers that are in contact with each other face-to-face, to produce a packaging bag. In the tubular film deformed into a flat shape, the facing second resin layers constituting the film, i.e., the inner surfaces of the film, are in contact with each other. In step (2), a packaging bag is produced from the tubular film deformed into a flat shape without releasing the contact between the facing second resin layers. For example, in a tubular film deformed into a flat shape, parts of the second resin layer that are in contact with each other and face to face are joined together to form a sealed portion, and then the film is cut to produce a packaging bag.For example, in a laminated film obtained by cutting a tubular film deformed into a flat shape, for example along the flow direction, parts of the second resin layer that are in contact with each other and face to face are joined together to form a sealed portion, and then the film is cut to produce a packaging bag.

[0054] Examples of methods for forming the sealed portion include heat sealing methods such as bar sealing, rotary roll sealing, belt sealing, impulse sealing, high frequency sealing, and ultrasonic sealing.

[0055] According to the manufacturing method of the present disclosure, the first surface of the second resin layer that contacts the first resin layer is not directly exposed to the outside air both during and after the manufacturing of the packaging bag. Therefore, it is possible to prevent foreign matter such as dust and dirt from adhering to the first surface of the second resin layer from the time of manufacturing the packaging bag until the first resin layer is peeled off and removed. When the packaging bag is used, the first surface of the second resin layer is exposed by peeling off and removing the first resin layer from the second resin layer of the packaging bag. This first surface is a clean surface in which the adhesion of foreign matter is prevented.

[0056] In addition, by deforming the tubular film into a flat shape, the inner surface of the tubular film is kept clean without contacting the outside air. By performing the bag making process while the inner surfaces of the tubular film deformed into a flat shape are in contact with each other, a packaging bag can be manufactured while the inner surface is kept clean without contacting the outside air. That is, the second surface of the second resin layer is a clean surface in which adhesion of foreign matter is suppressed. Therefore, according to the method of the present disclosure, the bag making process does not necessarily have to be performed in a clean environment. When a higher degree of cleanliness is required, the bag making process may be performed in a clean environment. On the other hand, in a method in which both ends in the width direction of the tubular film are cut off at a predetermined width to separate it into two films, and then the two films are overlapped and made into a bag, the outside air comes into contact with both sides of the film before the bag making process, so that it may not be possible to sufficiently suppress adhesion of foreign matter to the inner surface of the packaging bag.

[0057] An example of a bag making process is described below. Both ends of the flattened film in the width direction that intersect (for example, perpendicular to) the flow direction (extrusion direction) are heat-sealed along the flow direction, and the portions extending in the width direction of the film are heat-sealed at regular intervals in the flow direction to form sealed portions. Next, the film is cut in the width direction at a position slightly below the sealed portions extending in the width direction. Figure 4A1 shows a front view of the film, with the hatched portions indicating the sealed portions and the dotted lines indicating the places to be cut. In this manner, multiple packaging bags having an opening on one side are obtained.

[0058] Other examples of bag making processes are described below. Both ends of the flattened film in the width direction are heat-sealed along the machine direction, and the portions extending in the width direction of the film are heat-sealed at regular intervals in the machine direction to form sealed portions. Next, the film is cut in the machine direction at the center of the width direction, and then cut in the width direction at the sealed portions extending in the width direction (see FIG. 4A2). In this manner, multiple packaging bags having an opening on one side are obtained.

[0059] Other examples of bag making processes are described below. One end of the flattened film in the width direction is heat-sealed along the machine direction, and the portions extending in the width direction of the film are heat-sealed at regular intervals in the machine direction to form sealed portions. Next, the film is cut in the width direction at the sealed portions extending in the width direction (see FIG. 4B). In this manner, a plurality of packaging bags having an opening on one side are obtained.

[0060] Other examples of bag making processes are described below. The film deformed into a flat shape is heat-sealed in the machine direction at the center in the width direction, or the machine direction of the film is heat-sealed at regular intervals in the width direction, and the width direction of the film is heat-sealed at regular intervals in the machine direction to form a sealed portion. The portion heat-sealed along the machine direction of the film may be, for example, one to five rows, or one to three rows. Next, the film is cut along the machine direction at the sealed portion extending in the machine direction, and cut along the width direction at the sealed portion extending in the width direction (see Figs. 4C and 4D). In this manner, a plurality of packaging bags having an opening on one side are obtained.

[0061] Other examples of bag making processes are described below. The parts of the film that have been deformed into a flat shape that extend in the machine direction are heat-sealed at intervals in the width direction, and the parts of the film that extend in the width direction are heat-sealed at regular intervals in the machine direction to form sealed sections. Next, the film is cut in the machine direction at the sealed sections that extend in the machine direction, cut in the machine direction at the center of the film's width direction, and cut in the width direction at the sealed sections that extend in the width direction (see FIG. 4E). In this manner, multiple packaging bags with an opening on one side are obtained.

[0062] Other examples of bag making processes are described below. Both ends of the film in the width direction that has been deformed into a flat shape are heat-sealed along the machine direction, and the parts extending in the machine direction of the film are heat-sealed at regular intervals in the width direction, and the parts extending in the width direction of the film are heat-sealed at regular intervals in the machine direction to form sealed parts. The parts that are heat-sealed along the machine direction of the film may be, for example, one to five rows, or one to three rows. Next, the film is cut along the machine direction at the sealed parts extending in the machine direction, and the film is cut along the width direction at a position slightly below the sealed parts extending in the width direction (see FIG. 4F). In this manner, a plurality of packaging bags having an opening on one side are obtained.

[0063] In the above-mentioned examples of bag making, both ends in the width direction of the film are cut off to a predetermined width along the machine direction. This cutting may be performed before or after heat sealing.

[0064] For example, in a clean environment, an article is placed through the opening of the unsealed portion of the packaging bag produced above. Then, the opening of the packaging bag is heat sealed to form a sealed portion, thereby obtaining a package in which the article is accommodated in the packaging bag.

[0065] The above-mentioned first resin layer and second resin layer will be described in detail below. In the following description, the top sheet or the back sheet may be referred to as a "laminate".

[0066] <First resin layer> The first resin layer is provided so as to be peelable from the second resin layer. In this specification, the film made of the first resin layer obtained by peeling the first resin layer from the second resin layer of the packaging bag is also called a "peeling film." The film made of the second resin layer after the peeling is also called a "sealant film."

[0067] The peel strength between the first resin layer and the second resin layer is preferably 1.0 N / 15 mm width or less, more preferably 0.9 N / 15 mm width or less, even more preferably 0.8 N / 15 mm width or less, even more preferably 0.7 N / 15 mm width or less, and particularly preferably 0.6 N / 15 mm width or less. In the case of a packaging bag having such a peel strength, the first resin layer can be easily peeled from the second resin layer with a moderate force without damaging the second resin layer. The above peel strength is, for example, 0.01 N / 15 mm width, 0.05 N / 15 mm width, or 0.1 N / 15 mm width or more. In the case of a packaging bag having such a peel strength, the lifting of the first resin layer from the second resin layer can be suppressed, the appearance of the packaging bag is excellent, and the first resin layer can be suppressed from being peeled off from the second resin layer at an unintended time.

[0068] The peel strength is measured under the conditions of a peel angle of 180 degrees and a test speed of 50 mm / min. Specifically, the packaging bag is cut to cut out a test piece having a size of 15 mm in width and 100 mm in length. The first resin layer at one end in the length direction of the test piece is peeled off and folded back, and the end of the partially peeled first resin layer (peeling film) is attached to one grip of a tensile tester, and the end of the partially peeled second resin layer (sealant film) is attached to the other grip of the tensile tester. The initial chuck distance is 100 mm. Next, the grip to which the end of the first resin layer is attached is pulled at a speed of 50 mm / min in a direction of 180 degrees with respect to the surface of the test piece while maintaining the position of the test piece so that the angle is maintained, and the maximum strength (N) is measured. The maximum strength (N) measured for the 15 mm wide test piece is taken as the peel strength (N / 15 mm width).

[0069] From the viewpoints of peelability, strength, and heat resistance, the thickness of the first resin layer is preferably 3 μm or more, more preferably 5 μm or more, even more preferably 10 μm or more, and particularly preferably 15 μm or more. From the viewpoint of processability, the thickness of the first resin layer is preferably 150 μm or less, more preferably 130 μm or less, even more preferably 100 μm or less, and particularly preferably 50 μm or less.

[0070] The content ratio of the same resin material having the largest content in the first resin layer is preferably 70% by mass or more, more preferably 75% by mass or more, even more preferably 80% by mass or more, even more preferably 85% by mass or more, and particularly preferably 90% by mass or more, based on the mass of the first resin layer. A laminate having such a first resin layer has excellent recyclability. Specifically, the release film obtained by peeling the first resin layer from the laminate has excellent recyclability.

[0071] In this specification, the same type of resin material refers to, for example, polymers classified as polyolefin resins, polymers classified as polyamides, polymers classified as ethylene-vinyl alcohol copolymers, and polymers classified as polyesters. For example, polyolefin resins and polyesters are not classified as the same type of resin material.

[0072] In one embodiment, the above-mentioned "content ratio of the same type of resin material in the first resin layer" can be read as "content ratio of polyamide in the first resin layer," "content ratio of ethylene-vinyl alcohol copolymer in the first resin layer," "content ratio of polyester in the first resin layer," or "content ratio of polyethylene-based resin in the first resin layer."

[0073] In this specification, the term "polyolefin-based resin" refers to a concept that includes not only polyolefins but also modified polyolefins such as acid-modified polyolefins. In this specification, the term "polyethylene-based resin" refers to a concept that includes not only polyethylene but also modified polyethylenes such as acid-modified polyethylene.

[0074] In one embodiment, the first resin layer may include a heteroatom-containing resin layer containing a heteroatom-containing resin as a main component. The first resin layer may be a heteroatom-containing resin layer, or may include a heteroatom-containing resin layer and a polyolefin layer containing a polyolefin as a main component. In one embodiment, the heteroatom-containing resin layer may be in contact with the second resin layer. The laminate of this embodiment has excellent peelability of the first resin layer from the second resin layer. In one embodiment, the heteroatom-containing resin layer in the first resin layer has a density of 0.909 g / cm 3 It is in contact with the following polyethylene layer. The laminate of such an embodiment has an excellent balance between the peelability of the first resin layer from the second resin layer and the adhesion between the first resin layer and the second resin layer.

[0075] The laminate has a density of 0.909 g / cm in the polyolefin layer of the first resin layer and the second resin layer. 3 A heteroatom-containing resin layer may be provided between the following polyethylene layer. The laminate may have a polyolefin layer as a surface layer. Such a laminate has excellent appearance, and the heteroatom-containing resin layer can be made thin, thereby reducing production costs.

[0076] In one embodiment, the first resin layer may be a polymethylpentene layer containing polymethylpentene as a main component.

[0077] (Heteroatom-containing resin layer) The heteroatom-containing resin layer contains a heteroatom-containing resin as a main component. The first resin layer including the heteroatom-containing resin layer has a high Young's modulus and is excellent in peelability from the second resin layer. In addition, the laminate including the heteroatom-containing resin layer is excellent in puncture resistance. Therefore, a packaging bag including such a laminate is excellent in packaging hard items. The laminate including the heteroatom-containing resin layer is excellent in gas barrier properties such as oxygen barrier properties and water vapor barrier properties, heat resistance, and rigidity. The heteroatom-containing resin may be a biomass material from the viewpoint of reducing environmental load.

[0078] Examples of the heteroatom in the heteroatom-containing resin include oxygen, sulfur, nitrogen, and chlorine atoms. The heteroatom-containing resin has a heteroatom-containing group such as a hydroxy group, an amide bond, an ester bond, and an ether bond. Examples of the heteroatom-containing resin include polyamide, ethylene-vinyl alcohol copolymer, polyvinyl alcohol, polyvinylidene chloride, polyester, polyether polyol, and polyester polyol. Among these, polyamide, ethylene-vinyl alcohol copolymer, polyester, and polyvinyl alcohol are preferred from the viewpoints of heat resistance, rigidity, and puncture resistance, and polyamide and ethylene-vinyl alcohol copolymer are more preferred. These resin materials may be biomass materials from the viewpoint of reducing environmental load.

[0079] Examples of the polyamide include aliphatic polyamides and semi-aromatic polyamides. As the polyamide, aliphatic polyamides are preferred, and crystalline aliphatic polyamides are more preferred.

[0080] Examples of the aliphatic polyamide include aliphatic homopolyamide and aliphatic copolymer polyamide. In the following examples, polyamide is also referred to as "PA."

[0081] Specific examples of aliphatic homopolyamides include polycaprolactam or poly(6-aminocaproic acid) (PA6), polyenantholactam or poly(7-aminoenanthic acid) (PA7), polyundecane lactam or poly(11-aminoundecanoic acid) (PA11), polylauryllactam or poly(12-aminolauric acid) (PA12), polypentamethylene adipamide (PA56), polyhexamethylene adipamide (PA66), polytetramethylene sebacamide (PA410), polytetramethylene dodecamide (PA412), polypentamethylene azelamide (PA59), polypentamethylene sebacamide (PA510), polypentamethylene dodecamide (PA512), polyhexamethylene azelamide (PA69), Polyhexamethylene sebacamide (PA610), polyoctamethylene sebacamide (PA810), polyhexamethylene dodecamide (PA612), polynonamethylene adipamide (PA96), polynonamethylene azelamide (PA99), polynonamethylene sebacamide (PA910), polynonamethylene dodecamide (PA912), polydecamethylene adipamide (PA1 06), polydecamethylene azelamide (PA109), polydecamethylene decamamide (PA1010), polydecamethylene dodecamide (PA1012), polydodecamethylene adipamide (PA126), polydodecamethylene azelamide (PA129), polydodecamethylene sebacamide (PA1210) and polydodecamethylene dodecamide (PA1212).

[0082] Specific examples of aliphatic copolymer polyamides include caprolactam / hexamethylenediaminoadipic acid copolymer (PA6 / 66), caprolactam / hexamethylenediaminoazelaic acid copolymer (PA6 / 69), caprolactam / hexamethylenediaminosebacic acid copolymer (PA6 / 610), caprolactam / hexamethylenediaminoundecanoic acid copolymer (PA6 / 611), caprolactam / hexamethylenediaminododecanoic acid copolymer (PA6 / 612), caprolactam / amino undecanoic acid copolymer (PA6 / 11), caprolactam / lauryllactam copolymer (PA6 / 12), caprolactam / hexamethylenediaminoadipic acid / lauryllactam copolymer (PA6 / 66 / 12), caprolactam / hexamethylenediaminoadipic acid / hexamethylenediaminosebacic acid copolymer (PA6 / 66 / 610), caprolactam / hexamethylenediaminoadipic acid / hexamethylenediaminododecanedicarboxylic acid copolymer (PA6 / 66 / 612).

[0083] The relative viscosity of the aliphatic polyamide is preferably 1.5 or more, more preferably 2.0 or more, and even more preferably 2.5 or more. The relative viscosity of the aliphatic polyamide is preferably 5.0 or less, more preferably 4.5 or less. The relative viscosity of the aliphatic polyamide is measured at 25°C by dissolving 1g of polyamide in 100mL of 96% concentrated sulfuric acid in accordance with JIS K6920-2:2009.

[0084] The semi-aromatic polyamide is a polyamide having a constitutional unit derived from an aromatic diamine and a constitutional unit derived from an aliphatic dicarboxylic acid, or a polyamide having a constitutional unit derived from an aliphatic diamine and a constitutional unit derived from an aromatic dicarboxylic acid, for example, a polyamide composed of an aromatic diamine and an aliphatic dicarboxylic acid, or a polyamide composed of an aliphatic diamine and an aromatic dicarboxylic acid.

[0085] Examples of semi-aromatic polyamides include polyhexamethylene terephthalamide (PA6T), polyhexamethylene isophthalamide (PA6I), polynonamethylene terephthalamide (PA9T), polyhexamethylene adipamide / polyhexamethylene terephthalamide copolymer (PA66 / 6T), polyhexamethylene adipamide / polyhexamethylene isophthalamide copolymer (PA66 / 6I), polyhexamethylene terephthalamide / polycaproamide copolymer (PA6T / 6), polyhexamethylene isophthalamide / polycaproamide copolymer (PA6I / 6), polyhexamethylene terephthalamide / poly dodecamide copolymer (PA6T / 12), polyhexamethylene isophthalamide / polyhexamethylene terephthalamide copolymer (PA6I / 6T), polyhexamethylene terephthalamide / poly(2-methylpentamethylene terephthalamide) copolymer (PA6T / M5T), polyhexamethylene adipamide / polyhexamethylene terephthalamide / polyhexamethylene isophthalamide copolymer (PA66 / 6T / 6I), polyhexamethylene adipamide / polycaproamide / polyhexamethylene isophthalamide copolymer (PA66 / 6 / 6I) and polymetaxylylene adipamide (PAMXD6).

[0086] The melt volume rate (MVR) of the semi-aromatic polyamide is preferably 5 cm 3 / 10 minutes or more, preferably 10cm 3 The MVR of the semi-aromatic polyamide is preferably 200 cm 3 / 10 minutes or less, preferably 100cm 3 / 10 minutes or less. MVR is measured at a temperature of 275°C and a load of 5.00 kg in accordance with JIS K7210-1:2014.

[0087] The polyamide is preferably a crystalline aliphatic polyamide, such as PA6, PA11, PA12, PA66, PA610, PA612, PA1010, PA6 / 66, and PA6 / 66 / 12.

[0088] The melting point (Tm) of the crystalline aliphatic polyamide is preferably 170° C. or higher, more preferably 180° C. or higher. The Tm of the crystalline aliphatic polyamide is preferably 300° C. or lower, more preferably 250° C. or lower, and even more preferably 230° C. or lower. The Tm of the crystalline aliphatic polyamide is the melting peak temperature obtained by differential scanning calorimetry (DSC) in accordance with JIS K7121:2012.

[0089] From the viewpoint of film-forming property and processability, the polyamide melt flow rate (MFR) is preferably 0.1 g / 10 min or more, more preferably 0.3 g / 10 min or more, and even more preferably 0.5 g / 10 min or more. From the viewpoint of film-forming property and processability, the polyamide MFR is preferably 30 g / 10 min or less, more preferably 20 g / 10 min or less, even more preferably 10 g / 10 min or less, and particularly preferably 5 g / 10 min or less. The polyamide MFR is measured by the A method at a temperature of 235°C and a load of 2.16 kg in accordance with JIS K7210-1:2014. The measurement temperature can be changed depending on the melting point of the polyamide.

[0090] Ethylene-vinyl alcohol copolymer (EVOH) can be obtained, for example, by copolymerizing ethylene with a vinyl ester monomer and then saponifying the copolymer. The copolymerization of ethylene with a vinyl ester monomer can be carried out by any known polymerization method, such as solution polymerization, suspension polymerization, or emulsion polymerization.

[0091] As the vinyl ester monomer, vinyl acetate is generally used, but other vinyl ester monomers may be used, such as aliphatic vinyl esters such as vinyl formate, vinyl propionate, vinyl valerate, vinyl butyrate, vinyl isobutyrate, vinyl pivalate, vinyl caprate, vinyl laurate, vinyl stearate, and vinyl versatate, and aromatic vinyl esters such as vinyl benzoate.

[0092] The content of structural units derived from ethylene in EVOH (ethylene content) is preferably 20 mol% or more, more preferably 25 mol% or more, from the viewpoint of processability of the laminate. The ethylene content in EVOH is preferably 60 mol% or less, more preferably 50 mol% or less, from the viewpoint of heat resistance, oxygen barrier property, and water vapor barrier property of the laminate. The ethylene content is measured by NMR.

[0093] The average saponification degree of EVOH is preferably 90 mol% or more, more preferably 95 mol% or more, and further preferably 99 mol% or more. The average saponification degree is measured in accordance with JIS K6726:1994 (wherein EVOH is used as a solution uniformly dissolved in a water / methanol solvent).

[0094] From the viewpoint of heat resistance, the melting point (Tm) of EVOH is preferably 140° C. or higher, more preferably 145° C. or higher, and even more preferably 150° C. or higher. The Tm of EVOH is preferably 200° C. or lower, more preferably 195° C. or lower, and even more preferably 190° C. or lower. The Tm of EVOH is the melting peak temperature obtained by DSC in accordance with JIS K7121:2012.

[0095] From the viewpoint of film-forming property and processability, the melt flow rate (MFR) of EVOH is preferably 0.1 g / 10 min or more, more preferably 0.3 g / 10 min or more, and even more preferably 0.5 g / 10 min or more. From the viewpoint of film-forming property and processability, the MFR of EVOH is preferably 30 g / 10 min or less, more preferably 20 g / 10 min or less, even more preferably 10 g / 10 min or less, and particularly preferably 5 g / 10 min or less. The MFR of EVOH is measured by the A method at a temperature of 190° C. and a load of 2.16 kg in accordance with JIS K7210-1:2014. The measurement temperature may be 210° C. depending on the melting point of EVOH.

[0096] EVOH may be modified by a known method, such as urethanization, acetalization, cyanoethylation, or oxyalkylenation.

[0097] The average saponification degree of polyvinyl alcohol (PVA) is preferably 70 mol% or more, more preferably 75 mol% or more, further preferably 80 mol% or more, and particularly preferably 85 mol% or more. The average saponification degree is measured in accordance with JIS K6726:1994.

[0098] Examples of polyesters include polyethylene terephthalate (PET), polybutylene terephthalate (PBT), polyethylene naphthalate (PEN), 1,4-polycyclohexylene dimethylene terephthalate, and terephthalic acid-cyclohexanedimethanol-ethylene glycol copolymer. Among these, PET is preferred.

[0099] The content of the heteroatom-containing resin in the heteroatom-containing resin layer is preferably more than 50% by mass, more preferably 60% by mass or more, even more preferably 70% by mass or more, still more preferably 80% by mass or more, and particularly preferably 90% by mass or more, which can improve the above-mentioned physical properties such as the heat resistance of the packaging bag.

[0100] The heteroatom-containing resin layer may contain additives, such as antiblocking agents, slip agents, UV absorbers, antioxidants, light stabilizers, fillers, reinforcing agents, antistatic agents, compatibilizers, crosslinking agents, pigments, and dyes.

[0101] From the viewpoint of heat resistance of the laminate, the thickness of the heteroatom-containing resin layer is preferably 0.5 μm or more, more preferably 1 μm or more, even more preferably 3 μm or more, and particularly preferably 5 μm or more. From the viewpoint of recyclability of the laminate, the thickness of the heteroatom-containing resin layer is preferably 50 μm or less, more preferably 40 μm or less, even more preferably 30 μm or less, and particularly preferably 20 μm or less.

[0102] (Polyolefin layer) The polyolefin layer in the first resin layer contains polyolefin as a main component. Examples of polyolefin include polyethylene, polypropylene, and polymethylpentene. The polyolefin layer is preferably a polyethylene layer or a polypropylene layer, and more preferably a polyethylene layer. The polyolefin may be a biomass polyolefin from the viewpoint of reducing the environmental load.

[0103] From the viewpoint of film-forming property and processability, the MFR of the polyolefin is preferably 0.1 g / 10 min or more, more preferably 0.3 g / 10 min or more, and even more preferably 0.5 g / 10 min or more. From the viewpoint of film-forming property and processability, the MFR of the polyolefin is preferably 30 g / 10 min or less, more preferably 20 g / 10 min or less, even more preferably 10 g / 10 min or less, and particularly preferably 5 g / 10 min or less. The MFR of the polyolefin is measured by the A method under a load of 2.16 kg in accordance with JIS K7210-1:2014. The measurement temperature of the MFR is set according to the melting point of the polyolefin, and is 190 ° C. for polyethylene and 230 ° C. for polypropylene.

[0104] The content of polyolefin in the polyolefin layer is preferably more than 50% by mass, more preferably 60% by mass or more, further preferably 70% by mass or more, and particularly preferably 80% by mass or more.

[0105] The polyolefin layer in the first resin layer may further contain a modified polyolefin from the viewpoint of adhesion to the heteroatom-containing resin layer. The modified polyolefin may be, for example, a polyolefin modified with an unsaturated carboxylic acid such as maleic acid or fumaric acid, or an acid anhydride, ester, or metal salt thereof, particularly a graft modified polyolefin. The modified polyolefin may be a biomass material from the viewpoint of reducing the environmental load.

[0106] From the viewpoint of film-forming property and processability, the MFR of the modified polyolefin is preferably 0.1 g / 10 min or more, more preferably 0.3 g / 10 min or more, and even more preferably 0.5 g / 10 min or more. From the viewpoint of film-forming property and processability, the MFR of the modified polyolefin is preferably 30 g / 10 min or less, more preferably 20 g / 10 min or less, even more preferably 10 g / 10 min or less, and particularly preferably 5 g / 10 min or less. The MFR of the modified polyolefin is measured by the A method under a load of 2.16 kg in accordance with JIS K7210-1:2014. The measurement temperature of the MFR is set according to the melting point of the modified polyolefin, and is 190 ° C. for modified polyethylene and 230 ° C. for modified polypropylene.

[0107] The content of the modified polyolefin in the polyolefin layer is preferably less than 50% by mass, more preferably 40% by mass or less, even more preferably 30% by mass or less, and particularly preferably 20% by mass or less. The content of the modified polyolefin in the polyolefin layer is preferably 1% by mass or more, more preferably 3% by mass or more, and even more preferably 5% by mass or more.

[0108] The polyolefin layer may contain a resin material other than polyolefin and modified polyolefin, such as (meth)acrylic resin, vinyl resin, cellulose resin, polyamide, polyester, and ionomer resin.

[0109] The polyolefin layer may contain the additives described above.

[0110] The thickness of the polyolefin layer is preferably 1 μm or more, more preferably 5 μm or more, and even more preferably 10 μm or more from the viewpoint of the strength, heat resistance, and recyclability of the laminate. The thickness of the polyolefin layer is preferably 100 μm or less, more preferably 50 μm or less, and even more preferably 30 μm or less from the viewpoint of the processability of the laminate.

[0111] ((Polyethylene layer)) The polyethylene layer in the first resin layer contains polyethylene as a main component. Examples of polyethylene include high-density polyethylene, medium-density polyethylene, low-density polyethylene, and linear low-density polyethylene. From the viewpoint of heat resistance of the tubular film during heat sealing, the polyethylene layer containing high-density polyethylene as a main component is preferable. From the viewpoint of reducing the environmental load, the polyethylene may be biomass polyethylene.

[0112] The MFR of the polyethylene in the first resin layer is preferably 0.1 g / 10 min or more, more preferably 0.3 g / 10 min or more, and even more preferably 0.5 g / 10 min or more, from the viewpoint of film-forming property and processability. The MFR of the polyethylene is preferably 30 g / 10 min or less, more preferably 20 g / 10 min or less, even more preferably 10 g / 10 min or less, and particularly preferably 5 g / 10 min or less, from the viewpoint of film-forming property and processability. The MFR of the polyethylene is measured by the A method at a temperature of 190° C. and a load of 2.16 kg in accordance with JIS K7210-1:2014.

[0113] From the viewpoint of heat resistance, the melting point (Tm) of the polyethylene in the first resin layer is preferably 100° C. or higher, more preferably 105° C. or higher, even more preferably 110° C. or higher, particularly preferably 120° C. or higher, and preferably 140° C. or lower. Tm is the melting peak temperature obtained by DSC in accordance with JIS K7121:2012.

[0114] The polyethylene content in the polyethylene layer is preferably more than 50% by mass, more preferably 60% by mass or more, even more preferably 70% by mass or more, and particularly preferably 80% by mass or more.

[0115] The polyethylene layer in the first resin layer may further contain modified polyethylene from the viewpoint of adhesion to the heteroatom-containing resin layer. Examples of modified polyethylene include polyethylene modified with unsaturated carboxylic acids such as maleic acid and fumaric acid, or their acid anhydrides, esters, or metal salts, particularly graft modified polyethylene. The modified polyethylene may be modified high density polyethylene or maleic anhydride graft modified high density polyethylene. The modified polyethylene may be a biomass material from the viewpoint of reducing the environmental load.

[0116] From the viewpoint of film-forming property and processability, the MFR of the modified polyethylene is preferably 0.1 g / 10 min or more, more preferably 0.3 g / 10 min or more, and even more preferably 0.5 g / 10 min or more. From the viewpoint of film-forming property and processability, the MFR of the modified polyethylene is preferably 30 g / 10 min or less, more preferably 20 g / 10 min or less, even more preferably 10 g / 10 min or less, and particularly preferably 5 g / 10 min or less. The MFR of the modified polyethylene is measured by the A method at a temperature of 190° C. and a load of 2.16 kg in accordance with JIS K7210-1:2014.

[0117] The content of the modified polyethylene in the polyethylene layer is preferably less than 50% by mass, more preferably 40% by mass or less, even more preferably 30% by mass or less, and particularly preferably 20% by mass or less. The content of the modified polyethylene in the polyethylene layer is preferably 1% by mass or more, more preferably 3% by mass or more, and even more preferably 5% by mass or more.

[0118] ((Polypropylene layer)) The polypropylene layer in the first resin layer contains polypropylene as a main component. The laminate including the polypropylene layer has excellent oil resistance.

[0119] The polypropylene may be any one of a propylene homopolymer (homopolypropylene), a propylene random copolymer (random polypropylene) and a propylene block copolymer (block polypropylene), or may be a mixture of two or more selected from these. As the polypropylene, from the viewpoint of reducing the environmental load, biomass polypropylene or mechanically recycled or chemically recycled polypropylene may be used.

[0120] A propylene homopolymer is a polymer of propylene alone. A propylene random copolymer is a random copolymer of propylene and an α-olefin other than propylene. A propylene block copolymer is a copolymer having at least a polymer block of propylene and at least a polymer block of an α-olefin other than propylene.

[0121] Examples of α-olefins other than propylene include α-olefins having 2 to 20 carbon atoms, specifically, ethylene, 1-butene, 1-pentene, 1-hexene, 1-octene, 1-decene, 1-dodecene, 1-tetradecene, 1-hexadecene, 1-octadecene, 1-eicosene, 3-methyl-1-butene, 4-methyl-1-pentene, and 6-methyl-1-heptene.

[0122] Among polypropylenes, propylene random copolymers are preferred from the viewpoint of transparency. When the rigidity and heat resistance of the packaging bag are important, propylene homopolymers are preferred. When the impact resistance of the packaging bag is important, propylene block copolymers are preferred.

[0123] The density of polypropylene is, for example, 0.88 g / cm 3 More than 0.92g / cm 3 The density of polypropylene is measured in accordance with JIS K7112:1999, Method D (density gradient tube method, 23° C.).

[0124] From the viewpoint of heat resistance, the melting point (Tm) of polypropylene is preferably 120° C. or higher, more preferably 130° C. or higher, and even more preferably 150° C. or higher. The Tm of polypropylene is preferably 170° C. or lower. Tm is the melting peak temperature obtained by DSC in accordance with JIS K7121:2012.

[0125] The polypropylene content in the polypropylene layer is preferably more than 50% by mass, more preferably 60% by mass or more, even more preferably 70% by mass or more, still more preferably 80% by mass or more, and particularly preferably 90% by mass or more.

[0126] <Second resin layer> The second resin layer is a sealant layer containing polyolefin as a main component. The second resin layer is a layer facing the storage space of the packaging bag. In one embodiment, the packaging bag obtained by separating and removing the first resin layer from the laminate can be made into a mono-material bag.

[0127] Examples of polyolefins include polyethylene, polypropylene, and polymethylpentene. Among these, polyethylene and polypropylene are preferred, and polyethylene is more preferred. The polyolefin may be a biomass polyolefin from the viewpoint of reducing the environmental load.

[0128] The MFR of the polyolefin in the second resin layer is preferably 0.1 g / 10 min or more, more preferably 0.3 g / 10 min or more, and even more preferably 0.5 g / 10 min or more, from the viewpoint of film-forming property and processability. The MFR of the polyolefin is preferably 30 g / 10 min or less, more preferably 20 g / 10 min or less, even more preferably 10 g / 10 min or less, and particularly preferably 5 g / 10 min or less, from the viewpoint of film-forming property and processability. The MFR of the polyolefin is measured by the A method under a load of 2.16 kg in accordance with JIS K7210-1:2014. The measurement temperature of the MFR is set according to the melting point of the polyolefin, and is 190 ° C. for polyethylene and 230 ° C. for polypropylene.

[0129] The content of polyolefin in the second resin layer is preferably 80% by mass or more, more preferably 85% by mass or more, even more preferably 90% by mass or more, and particularly preferably 95% by mass or more, based on the mass of the second resin layer. A laminate having such a second resin layer has excellent recyclability. Specifically, a sealant film corresponding to the second resin layer after peeling and removing the first resin layer from the laminate has excellent recyclability.

[0130] In one embodiment, the above "polyolefin content in the second resin layer" can be read as "polyethylene content in the second resin layer" or "polypropylene content in the second resin layer."

[0131] In one embodiment, the second resin layer contains polyethylene as a main component. Examples of polyethylene include high density polyethylene, medium density polyethylene, low density polyethylene, and linear low density polyethylene, and from the viewpoint of heat sealability, low density polyethylene and linear low density polyethylene are preferred. From the viewpoint of reducing environmental load, the polyethylene may be biomass polyethylene.

[0132] From the viewpoint of a balance between heat resistance and heat sealability, the melting point (Tm) of the polyethylene in the second resin layer is preferably 80° C. or higher, more preferably 85° C. or higher, and preferably 140° C. or lower, more preferably 130° C. or lower. Tm is the melting peak temperature obtained by DSC in accordance with JIS K7121:2012.

[0133] In one embodiment, the second resin layer contains polypropylene as a main component. A laminate including such a second resin layer has excellent oil resistance.

[0134] Examples of polypropylene include propylene homopolymers, propylene random copolymers such as propylene-α-olefin random copolymers, and propylene block copolymers such as propylene-α-olefin block copolymers. Details of the α-olefins are as described above. From the viewpoint of reducing the environmental load, biomass polypropylene and mechanically recycled or chemically recycled polypropylene may be used as the polypropylene.

[0135] From the viewpoint of heat sealability, the density of the polypropylene in the second resin layer is, for example, 0.88 g / cm 3 More than 0.92g / cm 3 The density of polypropylene is measured in accordance with JIS K7112:1999, Method D (density gradient tube method, 23° C.).

[0136] From the viewpoint of a balance between heat resistance and heat sealability, the melting point (Tm) of the polypropylene in the second resin layer is preferably 120° C. or higher, more preferably 125° C. or higher, even more preferably 130° C. or higher, and preferably 160° C. or lower, more preferably 155° C. or lower, even more preferably 150° C. or lower. Tm is the melting peak temperature obtained by DSC in accordance with JIS K7121:2012.

[0137] The second resin layer may contain the above-mentioned additives.

[0138] From the viewpoints of strength and heat sealability, the thickness of the second resin layer is preferably 10 μm or more, more preferably 15 μm or more, even more preferably 20 μm or more, and particularly preferably 30 μm or more. From the viewpoint of processability, the thickness of the second resin layer is preferably 250 μm or less, more preferably 200 μm or less, even more preferably 150 μm or less, and particularly preferably 100 μm or less.

[0139] In one embodiment, the second resin layer includes at least a heat-sealable resin layer containing polyolefin such as polyethylene and polypropylene as a main component as a surface layer of the laminate. In one embodiment, the heat-sealable resin layer in the second resin layer is in contact with the first resin layer.

[0140] In one embodiment, the second resin layer has a density of 0.909 g / cm 3 The second resin layer includes at least the following polyethylene layer: In one embodiment, the polyethylene layer in the second resin layer is in contact with the first resin layer.

[0141] In one embodiment, the second resin layer has a density of 0.909 g / cm 3 The laminate includes a polyethylene layer and a heat-sealable resin layer containing polyethylene as a main component as a surface layer of the laminate. In one embodiment, the polyethylene layer in the second resin layer is in contact with the first resin layer.

[0142] In one embodiment, the second resin layer has a density of 0.909 g / cm 3 The heat-sealable resin layer further includes an intermediate layer containing polyethylene as a main component between the polyethylene layer and the heat-sealable resin layer containing polyethylene as a main component.

[0143] (Polyethylene layer) In one embodiment, the second resin layer has a density of 0.909 g / cm 3 The laminate having such a polyethylene layer can suppress lifting of the first resin layer from the second resin layer during the production of the laminate, and has good peel strength between the first resin layer and the second resin layer. 3 The following polyethylene layer has an excellent balance of adhesion to the heteroatom-containing resin layer and peelability.

[0144] The density of the polyethylene layer is preferably 0.908 g / cm 3 Less than or equal to 0.907 g / cm 3More preferably, 0.906 g / cm 3 More preferably, 0.905 g / cm 3 Below 0.904 g / cm, particularly preferably 0.904 g / cm 3 The density of the polyethylene layer is preferably 0.860 g / cm 3 More preferably, 0.870 g / cm 3 More preferably, 0.880 g / cm 3 More preferably, 0.890 g / cm 3 More preferably, 0.895 g / cm 3 The density of the polyethylene layer is measured in accordance with JIS K7112:1999, Method D (density gradient tube method, 23° C.).

[0145] In one embodiment, the polyethylene layer has a density of 0.909 g / cm 3 The polyethylene used is preferably polyethylene having a density of 0.909 g / cm 3 The following linear low density polyethylene is contained as a main component. Examples of linear low density polyethylene include ethylene-1-butene copolymer (C4-LLDPE) in which the comonomer is at least 1-butene, ethylene-1-hexene copolymer (C6-LLDPE) in which the comonomer is at least 1-hexene, and ethylene-1-octene copolymer (C8-LLDPE) in which the comonomer is at least 1-octene. In these copolymers, the comonomer is not limited to the above-mentioned one, and further comonomers may be used. The polyethylene may be biomass polyethylene from the viewpoint of reducing the environmental load.

[0146] The density of the polyethylene, such as linear low density polyethylene, is preferably 0.908 g / cm 3 Less than or equal to 0.907 g / cm 3 More preferably, 0.906 g / cm 3 More preferably, 0.905 g / cm 3 Below 0.904 g / cm, particularly preferably 0.904 g / cm 3The density of the polyethylene is preferably 0.860 g / cm 3 More preferably, 0.870 g / cm 3 More preferably, 0.880 g / cm 3 More preferably, 0.890 g / cm 3 More preferably, 0.895 g / cm 3 That's all.

[0147] Density is 0.909g / cm 3 From the viewpoint of film-forming property and processability, the MFR of the following polyethylene is preferably 0.1 g / 10 min or more, more preferably 0.3 g / 10 min or more, and further preferably 0.5 g / 10 min or more. 3 From the viewpoint of film-forming property and processability, the MFR of the following polyethylene is preferably 30 g / 10 min or less, more preferably 20 g / 10 min or less, further preferably 10 g / 10 min or less, and particularly preferably 5 g / 10 min or less. The MFR of polyethylene is measured by Method A at a temperature of 190° C. and a load of 2.16 kg in accordance with JIS K7210-1:2014.

[0148] Density is 0.909g / cm 3 The polyethylene may be a metallocene-based linear low-density polyethylene. A metallocene-based linear low-density polyethylene is a metallocene-based ethylene-α-olefin copolymer, i.e., an ethylene-α-olefin copolymer produced using a metallocene catalyst, and has a generally linear molecular structure.

[0149] Examples of the α-olefins copolymerized with ethylene include α-olefins having 3 to 12 carbon atoms, specifically propylene, 1-butene, 1-pentene, 1-hexene, 1-heptene, 1-octene, 4-methyl-1-pentene, 1-decene, and 1-dodecene. Among these, α-olefins having 3 to 8 carbon atoms are preferred. Examples of linear low density polyethylene include C4-LLDPE, C6-LLDPE, and C8-LLDPE.

[0150] The melting point (Tm) of the metallocene-based linear low-density polyethylene is preferably 110° C. or lower, more preferably 105° C. or lower, and even more preferably 100° C. or lower. The melting point (Tm) of the metallocene-based linear low-density polyethylene is preferably 80° C. or higher, more preferably 85° C. or higher, and even more preferably 88° C. or higher. Tm is the melting peak temperature obtained by DSC in accordance with JIS K7121:2012.

[0151] Among the metallocene-based linear low density polyethylenes, resins called metallocene-based ethylene plastomers are preferred. Specifically, metallocene-based ethylene plastomers are a type of copolymer of ethylene and α-olefin (ethylene-α-olefin copolymer) obtained by a metallocene catalyst. Metallocene-based ethylene plastomers have a density in the range called ultra-low density, which is relatively low among low densities, a uniform polymer distribution indexed by a narrow molecular weight distribution (Mw / Mn) derived from a polymerization method using a metallocene catalyst, which is a catalyst having uniform catalytic activity sites, and plastomer properties.

[0152] As the metallocene-based ethylene plastomer, a commercially available product may be used. For example, the commercially available product may be selected from the "Kernel (registered trademark)" series manufactured by Japan Polyethylene. For example, "KF260T", "KF360T" and "KS340T" may be mentioned.

[0153] Density is 0.909g / cm 3 The ratio (Mw / Mn) of weight average molecular weight (Mw) to number average molecular weight (Mn) of the following polyethylene is preferably 3.5 or less, more preferably 3.3 or less, and even more preferably 3.0 or less. The ratio (Mw / Mn) is 1.0 or more, preferably 1.5 or more, more preferably 1.8 or more, and even more preferably 2.1 or more.

[0154] Mw / Mn is defined as the ratio (Mw / Mn) of the weight average molecular weight (Mw) to the number average molecular weight (Mn) measured by gel permeation chromatography (GPC). Mw and Mn are measured by the following method. Apparatus: Waters GPC 150C type detector: MIRAN 1A infrared spectrophotometer (measurement wavelength, 3.42 μm) Column: Showa Denko AD806M / S x 3 [The column is calibrated by measuring Tosoh monodisperse polystyrene (A500, A2500, F1, F2, F4, F10, F20, F40, F288, each 0.5 mg / ml solution) and approximating the logarithm of the elution volume and molecular weight with a quadratic equation. The molecular weight of the sample is converted to polyethylene using the viscosity equation for polystyrene and polyethylene. The coefficients of the viscosity equation for polystyrene are α=0.723, logK=-3.967, and for polyethylene, α=0.707, logK=-3.407.] Measurement temperature: 140℃ Injection amount: 0.2ml Concentration: 20mg / 10mL Solvent: ortho-dichlorobenzene Flow rate: 1.0ml / min

[0155] The density of the polyethylene layer is 0.909 g / cm 3 The content of the following polyethylene is preferably more than 50% by mass, more preferably 60% by mass or more, even more preferably 70% by mass or more, still more preferably 80% by mass or more, and particularly preferably 90% by mass or more.

[0156] The polyethylene layer may contain the above-mentioned resin materials other than polyethylene. The polyethylene layer may contain the additives described above.

[0157] Density is 0.909g / cm 3 From the viewpoint of peel strength, the thickness of the following polyethylene layer is preferably 0.5 μm or more, more preferably 1 μm or more, further preferably 3 μm or more, and particularly preferably 5 μm or more. 3From the viewpoint of processability in film formation, the thickness of the following polyethylene layer is preferably 50 μm or less, more preferably 40 μm or less, further preferably 30 μm or less, and particularly preferably 20 μm or less.

[0158] (thermal adhesive resin layer) In one embodiment, the second resin layer is a thermally adhesive resin layer containing polyolefins such as polyethylene and polypropylene as a surface layer of the laminate. Such a thermally adhesive resin layer functions as a sealing layer in a packaging bag including the laminate. The thermally adhesive resin layer is a layer facing the storage space of the packaging bag.

[0159] In one embodiment, the second resin layer comprises a heat-sealable resin layer. In one embodiment, 0.909 g / cm 3 The polyethylene layer having the following density is one surface layer of the second resin layer, and the heat-fusible resin layer is the other surface layer of the second resin layer.

[0160] Examples of polyolefins include polyethylene and polypropylene, and polyethylene is preferred. Examples of polyethylene include linear low-density polyethylene, low-density polyethylene, medium-density polyethylene, high-density polyethylene, ethylene-vinyl acetate copolymer, and ethylene-(meth)acrylic acid ester copolymer. From the viewpoint of reducing environmental load, the polyethylene may be biomass polyethylene.

[0161] From the viewpoint of heat sealability, the heat-fusible resin layer preferably contains, as a main component, at least one polyethylene selected from linear low-density polyethylene and low-density polyethylene, such as C4-LLDPE, C6-LLDPE, and C8-LLDPE.

[0162] The total content of the linear low-density polyethylene and the low-density polyethylene in the heat-sealable resin layer is preferably more than 50% by mass, more preferably 60% by mass or more, even more preferably 70% by mass or more, still more preferably 80% by mass or more, and particularly preferably 90% by mass or more.

[0163] In one embodiment, the heat-sealable resin layer contains linear low-density polyethylene and low-density polyethylene. Such a heat-sealable resin layer has an excellent balance between heat sealability and low contamination (suppression of outgassing) of the article contained in the packaging bag.

[0164] The content ratio (LLDPE:LDPE) of linear low density polyethylene (LLDPE) to low density polyethylene (LDPE) in the heat-sealable resin layer is preferably 5:95 to 95:5, more preferably 10:90 to 90:10, and further preferably 20:80 to 80:20, on a mass basis.

[0165] The numerical range of the MFR of the polyethylene in the heat-fusible resin layer may be the same as the numerical range of the MFR of the polyethylene contained in the polyethylene layer of the first resin layer.

[0166] From the viewpoint of heat sealability, the melting point (Tm) of the polyethylene in the heat-fusible resin layer is preferably 140° C. or lower, more preferably 130° C. or lower, even more preferably 125° C. or lower, and is preferably 90° C. or higher, more preferably 95° C. or higher, even more preferably 100° C. or higher. Tm is the melting peak temperature obtained by DSC in accordance with JIS K7121:2012.

[0167] The heat-fusible resin layer may contain the above-mentioned additives.

[0168] The thickness of the heat-fusible resin layer is preferably 5 μm or more, more preferably 10 μm or more, even more preferably 15 μm or more, still more preferably 20 μm or more, and particularly preferably 25 μm or more. The thickness of the heat-fusible resin layer is preferably 200 μm or less, more preferably 150 μm or less, even more preferably 100 μm or less, still more preferably 80 μm or less, and particularly preferably 60 μm or less.

[0169] (Middle class) The second resin layer has a density of 0.909 g / cm 3 An intermediate layer containing polyethylene as a main component may be further provided between the polyethylene layer and the heat-sealable resin layer described below. From the viewpoint of the puncture resistance of the laminate, it is more preferable that the intermediate layer contains linear low-density polyethylene as a main component.

[0170] The polyethylene is preferably at least one selected from linear low-density polyethylene, low-density polyethylene, medium-density polyethylene, and high-density polyethylene, and from the viewpoint of heat sealability, more preferably at least one selected from linear low-density polyethylene and low-density polyethylene, and even more preferably linear low-density polyethylene. Examples of linear low-density polyethylene include C4-LLDPE, C6-LLDPE, and C8-LLDPE. From the viewpoint of reducing environmental load, the polyethylene may be biomass polyethylene.

[0171] The density of the polyethylene in the intermediate layer is preferably 0.925 g / cm 3 More preferably, 0.928 g / cm 3 More preferably, 0.930 g / cm 3 The laminate having such an intermediate layer has excellent puncture resistance. The density of the polyethylene in the intermediate layer is preferably 0.932 g / cm 3 The following is the result.

[0172] From the viewpoint of film-forming property and processability, the MFR of the polyethylene in the intermediate layer is preferably 0.1 g / 10 min or more, more preferably 0.3 g / 10 min or more, and even more preferably 0.5 g / 10 min or more. From the viewpoint of film-forming property and processability, the MFR of the polyethylene in the intermediate layer is preferably 30 g / 10 min or less, more preferably 20 g / 10 min or less, even more preferably 10 g / 10 min or less, and particularly preferably 5 g / 10 min or less. The MFR of the polyethylene is measured by the A method in accordance with JIS K7210-1:2014 under the conditions of a temperature of 190°C and a load of 2.16 kg.

[0173] From the viewpoint of heat resistance, the melting point (Tm) of the polyethylene in the intermediate layer is preferably 100° C. or higher, more preferably 105° C. or higher, even more preferably 110° C. or higher, particularly preferably 120° C. or higher, and preferably 140° C. or lower. Tm is the melting peak temperature obtained by DSC in accordance with JIS K7121:2012.

[0174] From the viewpoint of the puncture resistance and recyclability of the laminate, the polyethylene content in the intermediate layer is preferably more than 50% by mass, more preferably 60% by mass or more, even more preferably 70% by mass or more, still more preferably 80% by mass or more, and particularly preferably 90% by mass or more.

[0175] The intermediate layer may contain the above-mentioned resin material. The intermediate layer may contain the above-mentioned additives.

[0176] The thickness of the intermediate layer is preferably 1 μm or more, more preferably 3 μm or more, even more preferably 5 μm or more, and particularly preferably 10 μm or more. The thickness of the intermediate layer is preferably 50 μm or less, more preferably 40 μm or less, even more preferably 30 μm or less, and particularly preferably 25 μm or less.

[0177] <Design layer> The packaging bag may further include a design layer such as a printed layer. The design layer has an image. Examples of the image include characters, figures, patterns, symbols, and combinations thereof. The image may include text information such as the product name, the name of the item in the packaging bag, the manufacturer, and the names of raw materials. The image may be a single, solid color (so-called solid image).

[0178] The design layer may be provided, for example, on the surface of the first resin layer. For example, the design layer may be provided on the surface (outer surface) of the first resin layer opposite to the surface facing the second resin layer.

[0179] In one embodiment, the design layer contains a colorant. Examples of colorants include pigments such as inorganic pigments and organic pigments, as well as dyes such as acid dyes, direct dyes, disperse dyes, oil-soluble dyes, metal-containing oil-soluble dyes, and sublimation dyes. Examples of colorants also include fluorescent materials such as ultraviolet emitting materials that emit fluorescence by absorbing ultraviolet light, and infrared emitting materials that emit fluorescence by absorbing infrared light.

[0180] The content of the colorant in the design layer is preferably 1% by mass or more, more preferably 3% by mass or more, and even more preferably 5% by mass or more. The content of the colorant in the design layer is preferably 90% by mass or less, more preferably 70% by mass or less, and even more preferably 50% by mass or less.

[0181] The design layer may contain the above-mentioned resin material and may also contain the above-mentioned additives. The content of the resin material in the design layer is preferably 10% by mass or more, more preferably 30% by mass or more, and even more preferably 50% by mass or more. The content of the resin material in the design layer is preferably 99% by mass or less, more preferably 97% by mass or less, and even more preferably 95% by mass or less.

[0182] The design layer can be formed, for example, using an ink composition containing the above-mentioned components and, if necessary, a solvent. Methods for forming the design layer include, for example, gravure printing, offset printing, flexographic printing, screen printing, letterpress printing, and transfer printing. In one embodiment, from the viewpoint of reducing environmental load, flexographic printing may be used.

[0183] The thickness of the design layer is preferably 0.1 μm or more, more preferably 0.2 μm or more, and even more preferably 0.3 μm or more. The thickness of the design layer is preferably 10 μm or less, more preferably 5 μm or less, and even more preferably 3 μm or less.

[0184] <Laminated body configuration> 5 to 9 show schematic cross-sectional views of a laminate as a tubular film, or a laminate as a top sheet and a back sheet constituting a packaging bag according to one embodiment.

[0185] The laminate 1 in Fig. 5 includes a first resin layer 10 and a second resin layer 20 in this order in the thickness direction. The laminate 1 in Fig. 6 includes a second resin layer 20 having a density of 0.909 g / cm 3 5 except that it includes a polyethylene layer 22 and a thermally adhesive resin layer 24. The polyethylene layer 22 is in contact with the first resin layer 10.

[0186] 7 is similar to the laminate 1 of FIG 6, except that the first resin layer 10 comprises a polyolefin layer 12 and a heteroatom-containing resin layer 14. The heteroatom-containing resin layer 14 is in contact with the polyethylene layer 22.

[0187] The laminate 1 in Fig. 8 is similar to the laminate 1 in Fig. 6 except that the second resin layer 20 further includes an intermediate layer 23 between the polyethylene layer 22 and the heat-sealable resin layer 24. The laminate 1 in Fig. 9 is similar to the laminate 1 in Fig. 8 except that the first resin layer 10 includes a polyolefin layer 12 and a heteroatom-containing resin layer 14.

[0188] [Application] A high level of cleanliness is required for an article used in a clean environment such as a clean room. A packaging bag containing the article is brought into the clean environment and opened. Therefore, a high level of cleanliness is also required for the packaging bag. That is, when the packaging bag containing the article is brought into the clean environment, it is necessary to prevent foreign matter such as dust and dirt from adhering to the outer surface and / or inner surface of the packaging bag and the foreign matter from entering the clean environment together with the packaging bag. By using the packaging bag of the present disclosure, the intrusion of such foreign matter can be prevented, for example, as follows.

[0189] First, an article is accommodated in the packaging bag of the present disclosure in a clean environment, and degassed by vacuum degassing or the like as necessary, and the opening of the packaging bag is sealed to obtain a package in which the article is accommodated in the packaging bag. Degassing is not limited to vacuum degassing as long as the gas in the packaging bag can be removed. For example, degassing may be performed by pressing the packaging bag from the outside using a pressing member. The package is brought into the front room of the clean environment. Here, the first resin layer (peeling film) constituting the packaging bag is peeled off and removed. This exposes the first surface of the second resin layer (sealant film) constituting the packaging bag. As described above, the first surface of the second resin layer is a clean surface in which adhesion of foreign matter is suppressed. The packaging bag obtained by peeling off and removing the first resin layer has a small amount of adhesion of foreign matter on its surface. Such a packaging bag is brought into a clean environment. In the clean environment, the packaging bag is opened to take out the article and used. As described above, the second surface of the second resin layer (the inner surface of the packaging bag) is also a clean surface in which adhesion of foreign matter is suppressed as described above. In this way, foreign matter is prevented from entering the clean environment along with the packaging bag.

[0190] According to the above configuration, the packaging bag of the present disclosure does not need to be configured as a double-ply bag having at least an inner bag and an outer bag, or a triple-ply or more bag. However, there is no restriction on using the packaging bag of the present disclosure as an outer bag in a double-ply bag or a triple-ply or more bag.

[0191] Examples of the goods to be stored in the packaging bag include semiconductor products such as ICs and LSIs, semiconductor-related parts such as valves for semiconductor devices and filters for semiconductor manufacturing, precision machinery, magnetic disks, silicon wafers, O-rings, bellows, pharmaceutical products, products for regenerative medicine, and medicinal liquid products such as diluents for blood cell testing devices and artificial dialysis fluids. Examples of the goods to be stored in the packaging bag include dustproof clothing, dustproof gloves, and tools used in clean environments.

[0192] [Aspects of the present disclosure] The present disclosure relates to, for example, the following [1] to

[21] . [1] A method for producing a packaging bag, comprising: forming a tubular film by a coextrusion inflation method, the tubular film having at least a first resin layer constituting an outer surface of a tube, and a second resin layer constituting an inner surface of a tube, the second resin layer containing polyolefin as a main component, and deforming the film into a flat shape; and performing a bag-making process on the tubular film deformed into a flat shape or on a laminated film obtained by cutting the tubular film, without releasing the contact between the second resin layers that are in contact with each other and forming a packaging bag. The packaging bag comprises a top sheet and a back sheet facing the top sheet, the top sheet and the back sheet each comprising at least the first resin layer and the second resin layer that constitutes the inner surface of the packaging bag, the first resin layer is provided in the top sheet and the back sheet so as to be peelable from the second resin layer, and the packaging bag has a seal portion formed by joining a part of the second resin layer in the top sheet and a part of the second resin layer in the back sheet. [2] The method for manufacturing a packaging bag described in [1] above, wherein the first resin layer has at least a heteroatom-containing resin layer containing a heteroatom-containing resin as a main component, and the heteroatom-containing resin layer is in contact with the second resin layer. [3] The method for producing a packaging bag according to [2] above, wherein the heteroatom-containing resin comprises at least one selected from polyamide, ethylene-vinyl alcohol copolymer, polyester, and polyvinyl alcohol. [4] The method for producing a packaging bag described in [2] or [3] above, wherein the first resin layer further comprises a polyolefin layer containing polyolefin as a main component. [5] The method for producing a packaging bag according to [4] above, wherein the polyolefin layer further contains a modified polyolefin in addition to the polyolefin. [6] The method for producing a packaging bag according to any one of [1] to [5] above, wherein the second resin layer comprises a heat-sealable resin layer that constitutes the inner surface of the tube and contains polyolefin as a main component. [7] The method for producing a packaging bag described in [6] above, wherein the heat-sealable resin layer contains at least one type of polyethylene selected from linear low-density polyethylene and low-density polyethylene as a main component. [8] The second resin layer has a density of 0.909 g / cm 3 The method for producing a packaging bag according to any one of the above [2] to [7], further comprising: a polyethylene layer; and a heat-sealable resin layer containing polyethylene as a main component and constituting the inner surface of the tube, wherein the polyethylene layer in the second resin layer is in contact with the heteroatom-containing resin layer in the first resin layer. [9] The second resin layer has a density of 0.909 g / cm 3 The method for producing a packaging bag according to [8] above, further comprising an intermediate layer containing linear low-density polyethylene as a main component between the polyethylene layer and the heat-sealable resin layer.

[10] The method for manufacturing a packaging bag described in any one of [1] to [9], wherein the peel strength between the first resin layer and the second resin layer in the packaging bag, measured under conditions of a peel angle of 180 degrees and a test speed of 50 mm / min, is 1.0 N / 15 mm width or less.

[11] A packaging bag comprising a top sheet and a back sheet opposed to the top sheet, the top sheet and the back sheet each comprising at least a first resin layer and a second resin layer constituting the inner surface of the packaging bag, the second resin layer containing polyolefin as a main component, the first resin layer in the top sheet and the back sheet being provided so as to be peelable from the second resin layer, the packaging bag having a seal portion formed by joining a part of the second resin layer in the top sheet and a part of the second resin layer in the back sheet, the packaging bag being produced by a co-extrusion inflation method, the packaging bag comprising at least the first resin layer constituting the outer surface of a tube and the second resin layer constituting the inner surface of a tube, the packaging bag being produced by directly producing a bag from a film obtained by deforming a tubular film into a flat shape, or a laminated film obtained by cutting the film.

[12] A packaging bag comprising a top sheet and a back sheet opposed to the top sheet, each of the top sheet and the back sheet comprising at least a first resin layer and a second resin layer constituting an inner surface of the packaging bag, the second resin layer containing polyolefin as a main component, the first resin layer being provided in the top sheet and the back sheet so as to be peelable from the second resin layer, the packaging bag having a seal portion formed by joining a part of the second resin layer in the top sheet and a part of the second resin layer in the back sheet, the number of particles having a particle diameter of 0.2 μm or more adhering to the inner surface of the packaging bag measured using a particle counter is 100 particles / cm. 2 Below is the packaging bag.

[13] The packaging bag according to

[11] or

[12] , wherein the first resin layer comprises at least a heteroatom-containing resin layer containing a heteroatom-containing resin as a main component, and the heteroatom-containing resin layer is in contact with the second resin layer.

[14] The packaging bag according to

[13] , wherein the heteroatom-containing resin comprises at least one selected from polyamide, ethylene-vinyl alcohol copolymer, polyester, and polyvinyl alcohol.

[15] The packaging bag according to

[13] or

[14] , wherein the first resin layer further comprises a polyolefin layer containing polyolefin as a main component.

[16] The packaging bag according to

[15] , wherein the polyolefin layer further contains a modified polyolefin in addition to the polyolefin.

[17] The packaging bag according to any one of

[11] to

[16] , wherein the second resin layer comprises a heat-sealable resin layer that constitutes the inner surface of the packaging bag and contains polyolefin as a main component.

[18] The packaging bag according to

[17] , wherein the heat-sealable resin layer contains at least one type of polyethylene selected from linear low-density polyethylene and low-density polyethylene as a main component.

[19] The second resin layer has a density of 0.909 g / cm 3 The packaging bag according to any one of the above

[13] to

[18] , comprising: a polyethylene layer; and a heat-sealable resin layer containing polyethylene as a main component that constitutes the inner surface of the packaging bag, wherein the polyethylene layer in the second resin layer is in contact with the heteroatom-containing resin layer in the first resin layer.

[20] The second resin layer has a density of 0.909 g / cm 3 The packaging bag according to

[19] above, further comprising an intermediate layer containing linear low-density polyethylene as a main component between the polyethylene layer and the heat-sealable resin layer.

[21] The packaging bag according to any one of

[11] to

[20] , wherein the peel strength between the first resin layer and the second resin layer, measured under conditions of a peel angle of 180 degrees and a test speed of 50 mm / min, is 1.0 N / 15 mm width or less. EXAMPLES

[0193] The packaging bag and the manufacturing method thereof according to the present disclosure will be described in more detail based on examples. However, the packaging bag and the manufacturing method thereof according to the present disclosure are not limited to the examples.

[0194] [Raw material ingredients] The components used in the following Examples and Reference Examples are shown below. Polyamide (PA) UBE, 5033B, polyamide 6 / 66 copolymer, Melting point: 197°C, density: 1.14g / cm 3 , MFR: 4.0g / 10min (Temperature 235℃, Load 2.16kg) High density polyethylene (HDPE) Made by Prime Polymer, HZ5000SF, Melting point: 132°C, density: 0.954g / cm 3 , MFR: 0.66g / 10min · Linear low density polyethylene (LLDPE) Prime Polymer, SP0511, C6-LLDPE, Melting point: 98℃, density: 0.901g / cm 3 , MFR:1.2g / 10min · Linear low density polyethylene (LLDPE) Prime Polymer, UZ2021L, C6-LLDPE, Melting point: 120℃, density: 0.919g / cm 3 , MFR: 2.0g / 10min · Linear low density polyethylene (LLDPE) Prime Polymer, UZ3520L, C6-LLDPE, Melting point: 124℃, density: 0.931g / cm 3 , MFR:2.1g / 10min · Linear low density polyethylene (LLDPE) Ube Maruzen Polyethylene, UMERIT125FN, Melting point: 120℃, density: 0.924g / cm 3 , MFR:2.2g / 10min · Linear low density polyethylene (LLDPE) Nippon Polyethylene, Harmolex NF444N, Melting point: 121°C, density: 0.912g / cm 3 , MFR: 2.0g / 10min ·Low Density Polyethylene (LDPE) Ube Maruzen polyethylene, B128, Melting point: 114℃, density: 0.928g / cm 3 , MFR: 1.0g / 10min Maleic anhydride grafted high density polyethylene (mHDPE) Dow Chemical, BYNEL 40E 1053, adhesive resin, Melting point: 130℃, density: 0.960g / cm 3 , MFR: 2.0g / 10min

[0195] [Example 1] A mixture of 80% by mass of HDPE (HZ5000SF) and 20% by mass of mHDPE (BYNEL 40E 1053), PA (5033B), LLDPE (SP0511), LLDPE (UZ3520L), 80% by mass of LLDPE (UZ2021L) and 20% by mass of LDPE (B128) was extruded from an extruder through a multi-layer annular die using a five-layer coextrusion inflation apparatus, and the extruded mixture was inflated with air pressure while being taken up vertically to form a tubular film. The tubular film had a 15 μm thick HDPE layer constituting the outer surface of the tube, a 5 μm thick PA layer, a 15 μm thick LLDPE layer, a 20 μm thick LLDPE layer, and a 25 μm thick polyethylene blend layer constituting the inner surface of the tube, for a total thickness of 80 μm. The inner surfaces of the tubular films were brought into contact with each other using pinch rolls to flatten them. The mass % of a mixture indicates the content of each component in the mixture.

[0196] The flattened film was then sealed in a high-speed automatic three-sided seal bag making machine (BH-60D, manufactured by Totani Giken Kogyo) at a temperature of 140°C, a compression time of 0.8 seconds, and a pressure of 3kgf / cm. 2 Then, the bag was cut in a predetermined manner to prepare a three-sided sealed bag. This bag-making method is hereinafter referred to as "Method A".

[0197] The first resin layer, the release layer, is made of a 15 μm thick HDPE layer and a 5 μm thick PA layer, while the second resin layer, the sealant layer, is made of a 15 μm thick LLDPE layer, a 20 μm thick LLDPE layer, and a 25 μm thick polyethylene blend layer.

[0198] [Example 2] A mixture of 80% by mass of HDPE (HZ5000SF) and 20% by mass of mHDPE (BYNEL 40E 1053), PA (5033B), LLDPE (SP0511), LLDPE (UMERIT125FN), 80% by mass of LLDPE (NF444N) and 20% by mass of LDPE (B128) was extruded into a tube shape from an extruder through a multi-layer annular die using a 5-layer coextrusion inflation device in the same manner as in Example 1, and this was taken up vertically while being inflated with air pressure to form a tubular film. The tubular film had a 15 μm thick HDPE layer constituting the outer surface of the tube, a 5 μm thick PA layer, a 15 μm thick LLDPE layer, a 20 μm thick LLDPE layer, and a 25 μm thick polyethylene blend layer constituting the inner surface of the tube, and had a total thickness of 80 μm. The subsequent operations were the same as in Example 1 to produce a three-side sealed bag.

[0199] [Example 3] Except for changing the thickness of each layer, a tubular film having a total thickness of 95 μm was obtained in the same manner as in Example 1, which included a 30 μm thick HDPE layer constituting the outer surface of the tube, a 5 μm thick PA layer, a 20 μm thick LLDPE layer, a 20 μm thick LLDPE layer, and a 20 μm thick polyethylene blend layer constituting the inner surface of the tube. Subsequent operations were performed in the same manner as in Example 1 to produce a three-side sealed bag.

[0200] [Example 4] Except for changing the thickness of each layer, a tubular film having a total thickness of 95 μm was obtained in the same manner as in Example 2, which included a 30 μm thick HDPE layer constituting the outer surface of the tube, a 5 μm thick PA layer, a 20 μm thick LLDPE layer, a 20 μm thick LLDPE layer, and a 20 μm thick polyethylene blend layer constituting the inner surface of the tube. Subsequent operations were performed in the same manner as in Example 1 to produce a three-side sealed bag.

[0201] [Reference example 1] A tubular film was obtained in the same manner as in Example 1. The inner surfaces of the tubular film were brought together and flattened using a pinch roll. Both ends in the width direction of the flattened film were cut off to a predetermined width, divided into two films, and each was wound up to obtain two rolls of film. The films unwound from the two rolls were overlapped so that the polyethylene blend layers (thermally adhesive resin layers) were in contact with each other, and the films were then sealed using a high-speed three-sided automatic bag making machine (BH-60D, manufactured by Totani Giken Kogyo) at a temperature of 140°C, a compression time of 0.8 seconds, and a pressure of 3 kgf / cm. 2 Then, the mixture was heat-sealed at 100° C. and cut to prepare a three-sided sealed bag. This bag-making method is referred to as “Method B.”

[0202] [Reference examples 2~4] Using the tubular film obtained in Example 2, a three-side sealed bag of Reference Example 2 was produced in the same manner as Reference Example 1. Using the tubular film obtained in Example 3, a three-side sealed bag of Reference Example 3 was produced in the same manner as Reference Example 1. Using the tubular film obtained in Example 4, a three-side sealed bag of Reference Example 4 was produced in the same manner as Reference Example 1.

[0203] [Physical property evaluation] The methods for evaluating the physical properties of the three-side sealed bags, which are packaging bags, are described below. Unless otherwise specified, the environment during measurement of each physical property was a temperature of 23° C. and a humidity of 50% RH. Measurements were performed on three test pieces for each physical property, and the arithmetic mean value of the three values ​​obtained was recorded as the value of each physical property.

[0204] <Peel strength> The three-sided sealed bag was cut to obtain a test piece having a width of 15 mm and a length of 100 mm. Using the test piece and a benchtop tensile compression tester MCT-1150 (manufactured by AND Co., Ltd.) as a measuring instrument, the peel strength (N / 15 mm width) between the release layer and the sealant layer of the test piece was measured under the conditions of an initial chuck distance of 100 mm, a peel angle of 180 degrees, and a test speed of 50 mm / min.

[0205] <Puncture strength> The three-sided sealed bag was cut to obtain a test piece having a width of 5 cm and a length of 5 cm. The puncture strength of each of the test pieces was measured in accordance with JIS Z1707:2019. A benchtop tensile compression tester MCT-1150 (manufactured by AND Co., Ltd.) was used as the measuring device. A semicircular needle having a diameter of 1.0 mm and a tip radius of 0.5 mm was pierced into the sealant layer surface and the peel layer surface of the test piece at a test speed of 50 mm / min, and the puncture strength (N), which is the maximum strength until the needle penetrated the test piece, was measured.

[0206] <Seal strength> The tubular film was cut to obtain a test piece having a width of 15 mm and a length of 100 mm. Two test pieces were overlapped so that the sealant layers were in contact with each other, and the temperature was 140°C (one-sided heating), the compression time was 1 second, and the pressure was 1 kgf / cm. 2A 15 mm x 15 mm portion of one end of the test piece was heat-sealed under the conditions above to form a sealed portion, and a test specimen was obtained. Except for the test conditions being changed as follows, the seal strength (N / 15 mm width) was measured in accordance with JIS Z1707:2019 using a tabletop tensile compression tester MCT-1150 (manufactured by AND Co., Ltd.) as a measuring instrument under the conditions of chuck distance: 100 mm, peeling mode: T-type peeling, and test speed: 300 mm / min. Specifically, the test specimen was opened 180 degrees so that the sealed portion of the test specimen was in the center of the two grips of the test machine, and both ends of the test specimen were attached to the two grips of the test machine, respectively, and pulled at a speed of 300 mm / min until the sealed portion broke, to obtain the maximum strength (N). The maximum strength (N) measured for the 15 mm wide test specimen was taken as the heat seal strength (N / 15 mm width).

[0207] <Method for measuring the number of particles in liquid> The number of foreign objects (particle count) adhering to the inner surface of the three-sided sealed bag and the surface of the second resin layer was measured using a particle counter (KE-40 / KS-40AF, manufactured by Rion Co., Ltd.) under the condition of a measurement size of 0.2 μm or more. The bags were produced in a clean class 1000 environment. The measurements were carried out in a clean class 100 environment.

[0208] (Method for measuring the number of particles in liquid - inner surface of bag) 1. After purging the inside of the measuring device with pure water (25 mL x 4 times), The number of particles in the pure water blank was measured. 2. A 30 cm x 30 cm three-sided sealed bag was prepared in the same manner as in the Example or Reference Example. 3. Pure water whose blank value had been confirmed was poured into the three-side sealed bag, and after the pure water had spread around the inner surface of the three-side sealed bag, the three-side sealed bag was left to stand for 24 hours. 4. After purging the inside of the measuring device with pure water (25 mL x 4 times), the number of particles in the liquid was measured for 10 mL of water collected from the three-side sealed bag after step "3." above. The blank value for pure water was subtracted from this number of particles in the liquid to obtain the number of foreign objects (particle count) adhering to the inner surface of the three-side sealed bag.

[0209] (Method for measuring the number of particles in liquid - Surface of bag after peeling off the first resin layer) 1. After purging the inside of the measuring device with pure water (25 mL x 4 times), The number of particles in the pure water blank was measured. 2. Blank bags measuring 30cm x 30cm were made using blank film. 3. A 20 cm x 20 cm three-sided sealed bag was prepared in the same manner as in the Example or Reference Example. After the opening of the three-sided sealed bag was heat sealed to seal it, the first resin layer (peeling layer) of the bag was peeled off to obtain a sample bag with the surface (peeling surface) of the second resin layer exposed. Two types of test bags were prepared: test bag 1, which had a sample bag placed inside a blank bag, and test bag 2, which was only a blank bag. 4. Pure water whose blank value had been confirmed was poured into the blank bag (outside the sample bag) of test bag 1, and after the pure water had spread over the inner surface of the blank bag and the surface of the sample bag, test bag 1 was left standing for 24 hours. In the same manner, pure water whose blank value had been confirmed was poured into the blank bag of test bag 2, and after the pure water had spread over the inner surface of the blank bag, test bag 2 was left standing for 24 hours. 5. After purging the measuring device with pure water (25 mL x 4 times), the number of particles in the liquid was measured for 10 mL of water collected from test bag 1 and test bag 2 after step "4." above. The blank value for pure water and the number of particles in test bag 2 were subtracted from the number of particles in test bag 1 to calculate the number of foreign objects (number of particles) attached to the surface of the sample bag (surface (peeling surface) of the second resin layer of the three-side sealed bag).

[0210] [Table 1] [Explanation of symbols]

[0211] 1 ...Laminate 2 … Tubular film 10...First resin layer 12...Polyolefin layer 14...Heteroatom-containing resin layer 20...Second resin layer 22...Density is 0.909g / cm 3 Polyethylene layer below 23. Middle class 24…Thermofusible resin layer 40...Goods 50...Packaging bag 50a…Storage section 51…Upper 51a…Upper seal part 52…Lower 52a…Lower seal part 53…Side 53a...Side seal part 54…Surface sheet 55…Back sheet 60...Half cut wire

Claims

1. A method for manufacturing a packaging bag, comprising: The manufacturing method includes: A process of forming a tubular film including at least a first resin layer constituting an outer surface of the tube and a second resin layer constituting an inner surface of the tube, the second resin layer containing polyolefin as a main component, by a coextrusion inflation method, and deforming the film into a flat shape; a step of subjecting the tubular film deformed into a flat shape or the overlapped film obtained by cutting the film to a bag-making process without releasing the contact between the second resin layers that are in contact with each other and face to face, thereby producing a packaging bag; Including, The packaging bag comprises a top sheet and a back sheet facing the top sheet, the top sheet and the back sheet each comprising at least the first resin layer and the second resin layer constituting the inner surface of the packaging bag, the first resin layer in the top sheet and the back sheet is provided so as to be peelable from the second resin layer, and the packaging bag has a seal portion formed by joining a part of the second resin layer in the top sheet and a part of the second resin layer in the back sheet. A method for manufacturing packaging bags.

2. The method for producing a packaging bag according to claim 1, wherein the first resin layer comprises at least a heteroatom-containing resin layer containing a heteroatom-containing resin as a main component, and the heteroatom-containing resin layer is in contact with the second resin layer.

3. The method for producing a packaging bag according to claim 2, wherein the heteroatom-containing resin contains at least one selected from the group consisting of polyamide, ethylene-vinyl alcohol copolymer, polyester, and polyvinyl alcohol.

4. The method for producing a packaging bag according to claim 2 , wherein the first resin layer further comprises a polyolefin layer containing a polyolefin as a main component.

5. The method for producing a packaging bag according to claim 4, wherein the polyolefin layer further contains a modified polyolefin in addition to the polyolefin.

6. The method for producing a packaging bag according to claim 1 , wherein the second resin layer comprises a heat-sealable resin layer that constitutes the inner surface of the tube and contains polyolefin as a main component.

7. The method for producing a packaging bag according to claim 6, wherein the heat-sealable resin layer contains at least one type of polyethylene selected from linear low-density polyethylene and low-density polyethylene as a main component.

8. The second resin layer has a density of 0.909 g / cm 3 3. The method for producing a packaging bag according to claim 2, further comprising: a polyethylene layer in the second resin layer; and a heat-sealable resin layer containing polyethylene as a main component that constitutes the inner surface of the tube, wherein the polyethylene layer in the second resin layer is in contact with the heteroatom-containing resin layer in the first resin layer.

9. The second resin layer has a density of 0.909 g / cm 3 The method for producing a packaging bag according to claim 8, further comprising an intermediate layer containing linear low-density polyethylene as a main component between the polyethylene layer and the heat-sealable resin layer.

10. The method for manufacturing a packaging bag according to any one of claims 1 to 9, wherein the peel strength between the first resin layer and the second resin layer in the packaging bag, measured under conditions of a peel angle of 180 degrees and a test speed of 50 mm / min, is 1.0 N / 15 mm width or less.

11. A packaging bag, The packaging bag includes a top sheet and a back sheet facing the top sheet, The top sheet and the back sheet each include at least a first resin layer and a second resin layer constituting the inner surface of the packaging bag, and the second resin layer contains polyolefin as a main component, In the top sheet and the back sheet, the first resin layer is provided so as to be peelable from the second resin layer, The packaging bag has a seal portion formed by joining a part of the second resin layer on the top sheet and a part of the second resin layer on the back sheet, The packaging bag is produced by directly manufacturing a bag from a film obtained by deforming a tubular film having at least the first resin layer constituting the outer surface of a tube and the second resin layer constituting the inner surface of a tube produced by a co-extrusion inflation method into a flat shape or a laminated film obtained by cutting the film. packaging bag.

12. A packaging bag, The packaging bag includes a top sheet and a back sheet facing the top sheet, The top sheet and the back sheet each include at least a first resin layer and a second resin layer constituting the inner surface of the packaging bag, and the second resin layer contains polyolefin as a main component, In the top sheet and the back sheet, the first resin layer is provided so as to be peelable from the second resin layer, The packaging bag has a seal portion formed by joining a part of the second resin layer on the top sheet and a part of the second resin layer on the back sheet, The number of particles having a particle diameter of 0.2 μm or more adhering to the inner surface of the packaging bag measured using a particle counter is 100 particles / cm 2 Below is the packaging bag.

13. The packaging bag according to claim 11 or 12, wherein the first resin layer comprises at least a heteroatom-containing resin layer containing a heteroatom-containing resin as a main component, and the heteroatom-containing resin layer is in contact with the second resin layer.

14. The packaging bag according to claim 13, wherein the heteroatom-containing resin comprises at least one selected from polyamide, ethylene-vinyl alcohol copolymer, polyester, and polyvinyl alcohol.

15. The packaging bag according to claim 13 , wherein the first resin layer further comprises a polyolefin layer containing a polyolefin as a main component.

16. The packaging bag according to claim 15, wherein the polyolefin layer further contains a modified polyolefin in addition to the polyolefin.

17. The packaging bag according to claim 11 or 12, wherein the second resin layer comprises a heat-sealable resin layer that constitutes an inner surface of the packaging bag and contains polyolefin as a main component.

18. The packaging bag according to claim 17, wherein the heat-sealable resin layer contains, as a main component, at least one type of polyethylene selected from linear low-density polyethylene and low-density polyethylene.

19. The second resin layer has a density of 0.909 g / cm 3 The packaging bag according to claim 13, comprising: a polyethylene layer; and a heat-sealable resin layer containing polyethylene as a main component that constitutes the inner surface of the packaging bag, wherein the polyethylene layer in the second resin layer is in contact with the heteroatom-containing resin layer in the first resin layer.

20. The second resin layer has a density of 0.909 g / cm 3 The packaging bag according to claim 19, further comprising an intermediate layer containing linear low-density polyethylene as a main component between the polyethylene layer and the heat-sealable resin layer.

21. The packaging bag according to claim 11 or 12, wherein the peel strength between the first resin layer and the second resin layer, measured under conditions of a peel angle of 180 degrees and a test speed of 50 mm / min, is 1.0 N / 15 mm width or less.

Images