JP7371616B2 - Packaging materials and retort pouches or microwave pouches containing packaging materials - Google Patents

Description

The present invention relates to a packaging material and a packaging product such as a retort pouch or a microwave pouch comprising the packaging material.

Conventionally, various packaging materials have been developed as packaging materials for constructing packaging products such as bags and containers for filling and packaging various items such as food and beverages, pharmaceuticals, chemicals, cosmetics, sanitary products, daily necessities, etc. Proposed. The packaging material is composed of a laminate in which at least one stretched plastic film and a sealant layer for welding the packaging materials together are laminated. For example, Patent Document 1 discloses that as a packaging material, stretched polyethylene terephthalate film, silica-deposited stretched polyethylene terephthalate film, alumina-deposited stretched polyethylene terephthalate film, stretched nylon film, stretched polypropylene film, or co-extruded polypropylene/ethylene-vinyl alcohol copolymer film is used. It is proposed to use a stretched film or a composite film made by laminating two or more of these films.

Japanese Patent Application Publication No. 2015-120550

Packaging materials used to construct packaged products are required to have rigidity to prevent the packaged product from tearing even when a sharp member with a pointed tip comes into contact with the packaged product.

The present invention has been made in consideration of these points, and an object of the present invention is to provide a packaging material having rigidity.

One embodiment of the invention is a packaging material comprising:
Comprising a base material and a sealant layer,
The base material has only one biaxially oriented plastic film containing polyester as a main component,
The packaging material has a loop stiffness in one direction divided by the thickness of the packaging material of 0.00085 [N/μm] or more.

One embodiment of the invention is a packaging material comprising:
Comprising a base material and a sealant layer,
The base material has only one biaxially oriented plastic film containing polyester as a main component,
The biaxially stretched plastic film is a packaging material having a loop stiffness of 0.0017N or more in one direction.

One embodiment of the invention is a packaging material comprising:
Comprising a base material and a sealant layer,
The base material has only one biaxially oriented plastic film containing polyethylene terephthalate as a main component,
The packaging material has a puncture strength of 12N or more.

One embodiment of the invention is a packaging material comprising:
Comprising a base material and a sealant layer,
The base material has only one biaxially oriented plastic film containing polyester as a main component,
The packaging material has a value obtained by dividing the tensile strength of the biaxially stretched plastic film by the tensile elongation of 2.0 [MPa/%] or more in at least one direction.

In the packaging material according to one embodiment of the present invention, the biaxially stretched plastic film may contain polyethylene terephthalate as a main component.

In the packaging material according to an embodiment of the present invention, the packaging material may have a puncture strength of 12N or more.

A packaging material according to an embodiment of the invention may include a printed layer.

The packaging material according to an embodiment of the present invention may include a vapor deposition layer located on the surface of the biaxially stretched plastic film, and a gas barrier coating film located on the vapor deposition layer.

In the packaging material according to one embodiment of the present invention, the sealant layer may contain polypropylene as a main component.

In the packaging material according to one embodiment of the present invention, the sealant layer may include polyethylene having a melting point of 100°C or higher.

In the packaging material according to an embodiment of the present invention, the sealant layer includes a first layer mainly composed of polyethylene or polypropylene, and a second layer located on the inner side of the first layer and containing a mixed resin of polyethylene and polypropylene. It may have a layer.

One embodiment of the present invention is a retort pouch comprising the packaging material described above.

One embodiment of the present invention is a microwave pouch having a housing part,
packaging material listed as steam;
The microwave oven pouch includes a seal section that joins the inner surfaces of the packaging material to each other, and includes a steam release seal section that peels off due to an increase in pressure in the storage section.

According to the present invention, a packaging material having rigidity can be provided.

FIG. 1 is a front view showing a bag according to a first embodiment of the present invention. FIG. 2 is a cross-sectional view showing an example of a layered structure of packaging materials that constitute a bag. FIG. 7 is a cross-sectional view showing a modified example of the layered structure of the packaging material constituting the bag. FIG. 2 is a plan view showing an example of a loop stiffness measuring device. FIG. 5 is a cross-sectional view of the loop stiffness measuring device of FIG. 4 along line V-V. FIG. 3 is a diagram illustrating an example of a method for preparing a test piece used in a loop stiffness measuring device. It is a figure for explaining the process of attaching a test piece to a loop stiffness measuring device. It is a figure for explaining the process of forming a loop part in a test piece. It is a figure for explaining the process of applying a load to the loop part of a test piece. It is a figure for explaining the process of applying a load to the loop part of a test piece. It is a figure showing an example of layer composition of a sealant layer. It is a figure which shows an example of the method of filling a bag with contents. It is a front view showing a modified example of the bag. It is a front view showing a modified example of the bag. FIG. 2 is a longitudinal cross-sectional view showing an example of a container containing packaging material. FIG. 2 is a plan view showing an example of a container containing packaging material. It is a sectional view showing an example of the packaging material according to the second embodiment. It is a sectional view showing an example of the packaging material according to the second embodiment. FIG. 2 is a cross-sectional view showing an example of a base material of a barrier laminated film. It is a figure which shows an example of the result of analyzing the vapor deposition layer of a barrier laminated film by the time-of-flight type secondary ion mass spectrometer. FIG. 2 is a diagram showing an example of a film forming apparatus that forms a vapor deposition layer on a base material. It is a figure which shows an example of the measuring method of puncture strength. FIG. 2 is a plan view showing a test piece for evaluating impact strength. FIG. 23 is a cross-sectional view of the test piece shown in FIG. 22. It is a figure which shows an example of the measuring method of impact strength. FIG. 2 is a plan view showing a test piece for evaluating tearability. FIG. 3 is a diagram showing the evaluation results of Examples A1 to A3, Reference Examples A4 to A5 , and Comparative Examples A1 to A2. FIG. 3 is a diagram showing the evaluation results of Examples A1 to A3 and Comparative Examples A1 to A2. FIG. 3 is a diagram showing the evaluation results of Example C1 and Reference Examples C2 to C3. FIG. 3 is a diagram showing the evaluation results of Example C1 and Reference Examples C2 to C3.

First Embodiment An embodiment of the present invention will be described with reference to FIGS. 1 to 12. In addition, in the drawings attached to this specification, for convenience of illustration and ease of understanding, the scale and the vertical and horizontal dimension ratios are appropriately changed and exaggerated from those of the actual drawings.

In addition, terms such as "parallel," "orthogonal," and "identical" and values of length and angle used in this specification that specify shapes, geometric conditions, and their degrees must be strictly The term shall be interpreted to include the extent to which similar functions can be expected, without being bound by meaning.

FIG. 1 is a front view showing a bag 10 according to this embodiment. The bag 10 includes a storage section 17 that stores the contents. In addition, in FIG. 1, the bag 10 is shown in a state before the contents are stored therein. The configuration of the bag 10 will be described below.

Bag In this embodiment, the bag 10 is a gusset-type bag configured to be self-supporting. The bag 10 includes an upper part 11, a lower part 12, and a pair of side parts 13, and has a generally rectangular outline in a front view. In addition, names such as "upper part", "lower part", and "side part", and terms such as "upper part" and "lower part" are based on the state in which the bag 10 stands on its own with the gusset part facing down. It is merely a relative representation of the positions and directions of 10 and its constituent elements. The posture of the bag 10 during transportation or use is not limited by the names or terms used in this specification.

In this embodiment, the width direction of the bag 10 is also referred to as a first direction D1. The above-mentioned pair of side portions 13 face each other in the first direction D1. Further, a direction perpendicular to the first direction D1 is also referred to as a second direction D2. The bag 10 of this embodiment is assumed to be used in such a way that the consumer opens the bag 10 by tearing the bag 10 along the first direction D1.

As shown in FIG. 1, the bag 10 includes a front film 14 constituting the front surface, a back film 15 constituting the back surface, and a lower film 16 constituting the lower part 12. The lower film 16 is placed between the front film 14 and the back film 15 in a folded state at the folded portion 16f.

Note that the terms "front film", "back film", and "lower film" mentioned above are merely divisions of each film according to the positional relationship, and the method of providing the film when manufacturing the bag 10 is It is not intended to be limited by the above terms. For example, the bag 10 may be manufactured using one film in which the front film 14, the back film 15, and the lower film 16 are arranged in series, or the bag 10 may be manufactured using one film in which the front film 14 and the lower film 16 are arranged in series. It may be manufactured using a total of two films, a film and one back film 15, or a total of three films, one front film 14, one back film 15, and one bottom film 16. It may be manufactured using

The inner surfaces of the front film 14, the back film 15, and the lower film 16 are joined to each other by a seal portion. In a plan view of the bag 10 such as in FIG. 1, the seal portion is hatched.

As shown in FIG. 1, the seal portion has an outer edge seal portion extending along the outer edge of the bag 10. As shown in FIG. The outer edge seal portion includes a lower seal portion 12 a extending to the lower portion 12 and a pair of side seal portions 13 a extending along the pair of side portions 13 . In addition, in the bag 10 in a state before the contents are stored, as shown in FIG. 1, the upper part 11 of the bag 10 is an opening 11b. After the contents are stored in the bag 10, the inner surface of the front film 14 and the inner surface of the back film 15 are joined at the upper part 11, thereby forming the upper seal part 11a (see FIG. 6) and sealing the bag 10. Ru.

The side seal portion 13a and the upper seal portion 11a are seal portions formed by joining the inner surface of the front film 14 and the inner surface of the back film 15. On the other hand, the lower seal part 12a is formed by joining the inner surface of the front film 14 and the inner surface of the lower film 16, and by joining the inner surface of the back film 15 and the inner surface of the lower film 16. It includes a seal portion configured.

As long as the bag 10 can be sealed by joining opposing films together, there are no particular limitations on the method for forming the seal portion. For example, the sealed portion may be formed by melting the inner surfaces of the film by heating and welding the inner surfaces together, that is, by heat sealing. Alternatively, the seal portion may be formed by bonding the inner surfaces of opposing films together using an adhesive or the like.

Easy-to-open means The front film 14 and the back film 15 may be provided with easy-to-open means 25 for opening the bag 10 by tearing the front film 14 and the back film 15 along the first direction D1. . For example, as shown in FIG. 1, the easy-opening means 25 may include a notch 26 formed in the side seal portion 13a of the bag 10, which serves as a tearing point. Furthermore, a half-cut line formed by laser processing, a cutter, or the like may be provided as the easy-opening means 25 in a portion that becomes a path when the bag 10 is torn.

Further, although not shown, the easy-opening means 25 may include a notch or a group of scars formed in the region of the front film 14 and the back film 15 where the seal portion is formed. The scar group may include, for example, a plurality of through holes formed to penetrate the front film 14 and/or the back film 15. Alternatively, the scar group may include a plurality of holes formed on the outer surface of the front film 14 and/or the back film 15 so as not to penetrate the front film 14 and/or the back film 15.

Layer structure of the front film and back film Next, the layer structure of the front film 14 and the back film 15 will be explained. FIG. 2 is a cross-sectional view showing an example of the layered structure of the packaging material 30 that constitutes the front film 14 and the back film 15.

As shown in FIG. 2, the packaging material 30 includes a base material 35 and a sealant layer 70 bonded to the base material 35 by an adhesive layer 65. The substrate 35 has only one stretched plastic film, as shown at 60. The stretched plastic film 60 is located on the outer surface 30y side, and the sealant layer 70 is located on the inner surface 30x side opposite to the outer surface 30y. The inner surface 30x is a surface located on the accommodating portion 17 side.

Each film that makes up the packaging material 30, such as the stretched plastic film 60, the sealant film for making up the sealant layer 70, and the packaging material 30 has a machine direction and a vertical direction. The flow direction is the direction in which the film flows when forming the film, and is the so-called MD (Machine Direction). The vertical direction is a direction perpendicular to the flow direction, and is a so-called TD (Transverse Direction). In the bag 10 shown in FIG. 1, the direction in which the upper part 11 and the lower part 12 extend is the flow direction, and the direction in which the side parts 13 extend is the vertical direction.

The packaging material 30 of this embodiment is configured to have rigidity. Thereby, the bag 10 provided with the packaging material 30 can be made rigid. For example, it is possible to prevent the bag 10 from tearing when a sharp member with a pointed tip comes into contact with the bag 10. The thickness of the packaging material 30 is, for example, 60 μm or more, may be 70 μm or more, may be 80 μm or more, or may be 90 μm or more. Moreover, the thickness of the packaging material 30 may be 120 μm or less, 110 μm or less, or 100 μm or less.

Each layer of the packaging material 30 will be described in detail below.

(Stretched plastic film)
The stretched plastic film 60 is a biaxially stretched plastic film that is stretched in two predetermined directions. The stretching direction of the stretched plastic film 60 is not particularly limited. For example, the stretched plastic film 60 may be stretched in the direction in which the side portions 13 extend, or may be stretched in a direction perpendicular to the direction in which the side portions 13 extend. Furthermore, the stretching directions of the stretched plastic films 60 may be the same or different. The stretching ratio of the stretched plastic film 60 is, for example, 1.05 times or more.

In this embodiment, it is proposed to use, as the stretched plastic film 60, a stretched plastic film that has a loop stiffness of 0.0017 N or more in at least one direction and that contains polyester as a main component. In the following description, a stretched plastic film having a loop stiffness of 0.0017 N or more in at least one direction and containing polyester as a main component is also referred to as a high stiffness polyester film. The high stiffness polyester film has, for example, a loop stiffness of 0.0017 N or more in at least one of the machine direction (MD) or the vertical direction (TD). A high stiffness polyester film may have, for example, a loop stiffness of 0.0017 N or more in both the machine direction (MD) and the vertical direction (TD). By including the high stiffness polyester film, the packaging material 30 can have rigidity.
The polyester includes at least one aromatic dicarboxylic acid selected from terephthalic acid, isophthalic acid, and 2,6-naphthalene dicarboxylic acid, and at least one aromatic dicarboxylic acid selected from ethylene glycol, 1,3-propanediol, and 1,4-butanediol. Polyesters mainly composed of aromatic polyesters containing one type of aliphatic alcohol are preferred. For example, polyesters include polyethylene terephthalate (hereinafter also referred to as PET), polybutylene terephthalate (hereinafter also referred to as PBT), and the like. High stiffness polyester film Examples of high stiffness polyester films include high stiffness PET films containing 51% by mass or more of PET as a main component, high stiffness PBT films containing 51% by mass or more of PBT as a main component, etc. . The thickness of the high stiffness polyester film is preferably 5 μm or more, more preferably 7 μm or more. Further, the thickness of the high stiffness polyester film is preferably 25 μm or less, more preferably 20 μm or less.

Loop stiffness is a parameter representing the stiffness of a film such as a stretched plastic film. Hereinafter, a method for measuring loop stiffness will be described with reference to FIGS. 4 to 10. Note that the measurement method described below can be used not only for single-layer films such as stretched plastic films, but also for films with multiple layers such as vapor-deposited films and laminated films. A vapor-deposited film is a film that includes a single-layer film such as a stretched plastic film and a vapor-deposited layer formed on the single-layer film. A laminated film is a film that includes a plurality of laminated films, such as packaging material 30.

4 is a plan view showing the test piece 80 and the loop stiffness measuring device 85, and FIG. 5 is a cross-sectional view of the test piece 80 and the loop stiffness measuring device 85 in FIG. 4 taken along the line V-V. The test piece 80 is a rectangular film having long sides and short sides. In the present application, the length L1 of the long side of the test piece 80 was 150 mm, and the length L2 of the short side was 15 mm. As the loop stiffness measuring device 85, for example, No. 1 manufactured by Toyo Seiki Co., Ltd. is used. 581 Loop Stiffness Tester (registered trademark) LOOP STIFFNESS TESTER DA type can be used. Note that the length L1 of the long side of the test piece 80 can be adjusted as long as the test piece 80 can be gripped by a pair of chuck parts 86, which will be described later.

The loop stiffness measuring device 85 includes a pair of chuck parts 86 for gripping a pair of ends in the long side direction of the test piece 80, and a support member 87 that supports the chuck parts 86. The chuck section 86 includes a first chuck 861 and a second chuck 862. In the state shown in FIGS. 4 and 5, the test piece 80 is placed on a pair of first chucks 861, and the second chuck 862 and the first chuck 861 are still holding the test piece 80. Not yet. As will be described later, during measurement, the test piece 80 is held between the first chuck 861 and the second chuck 862 of the chuck section 86. The second chuck 862 may be connected to the first chuck 861 via a hinge mechanism.

If the film to be measured, such as a stretched plastic film, vapor-deposited film, or laminated film, is available in a state before the film is processed into a packaging product, the test piece 80 is prepared by cutting the film to be measured. It's okay. Alternatively, the test piece 80 may be produced by cutting a packaging product, such as a bag, made from the packaging material 30 and removing the film to be measured. FIG. 6 is a diagram showing an example of a method for preparing a test piece 80 by cutting the front film 14 or the back film 15 of the bag 10. When measuring the loop stiffness of the packaging material 30 in the flow direction, the front film 14 or the back film 15 of the bag 10 is cut so that the long side direction of the test piece coincides with the flow direction, as shown by reference numeral 80A in FIG. to prepare a test piece. When measuring the loop stiffness of the packaging material 30 in the vertical direction, the front film 14 or the back film 15 of the bag 10 is cut so that the long side direction of the test piece coincides with the vertical direction, as shown by reference numeral 80B in FIG. to prepare a test piece.

A method of measuring the loop stiffness of the test piece 80 using the loop stiffness measuring device 85 will be described. First, as shown in FIGS. 4 and 5, the test piece 80 is placed on the first chuck 861 of a pair of chuck parts 86 that are spaced apart from each other by L3. In the present application, the interval L3 is set so that the length of the loop portion 81 (hereinafter also referred to as loop length), which will be described later, is 60 mm. The test piece 80 includes an inner surface 80x located on the first chuck 861 side and an outer surface 80y located on the opposite side of the inner surface 80x. When the test piece 80 is made of the packaging material 30, the inner surface 80x and the outer surface 80y of the test piece 80 correspond to the inner surface 30x and the outer surface 30y of the packaging material 30. When forming a loop portion 81 to be described later on the test piece 80, the inner surface 80x is located inside the loop portion 81, and the outer surface 80y is located outside the loop portion 81. Subsequently, as shown in FIG. 7, the second chuck 862 is placed on top of the test piece 80 so as to grip the end of the test piece 80 in the long side direction between it and the first chuck 861.

Subsequently, as shown in FIG. 8, at least one of the pair of chuck parts 86 is slid on the support member 87 in a direction in which the distance between the pair of chuck parts 86 is reduced. Thereby, the loop portion 81 can be formed in the test piece 80. A test piece 80 shown in FIG. 8 has a loop portion 81, a pair of intermediate portions 82, and a pair of fixing portions 83. The pair of fixing parts 83 are parts of the test piece 80 that are gripped by the pair of chuck parts 86 . The pair of intermediate portions 82 are portions of the test piece 80 located between the loop portion 81 and the pair of intermediate portions 82 . As shown in FIG. 7, the chuck portion 86 is slid on the support member 87 until the inner surfaces 80x of the pair of intermediate portions 82 come into contact with each other. Thereby, the loop portion 81 having a loop length of 60 mm can be formed. The loop length of the loop portion 81 is defined as the position P1 where the surface on the loop portion 81 side of one second chuck 862 and the test piece 80 intersect, and the intersection between the surface on the loop portion 81 side of the other second chuck 862 and the test piece 80. This is the length of the test piece 80 between the intersection point P2. When the thickness of the test piece 80 is ignored, the above-mentioned interval L3 is a value obtained by adding 2×t to the length of the loop portion 81. t is the thickness of the second chuck 862 of the chuck portion 86.

Thereafter, as shown in FIG. 9, the posture of the chuck part 86 is adjusted so that the protruding direction Y of the loop part 81 with respect to the chuck part 86 is in the horizontal direction. For example, the attitude of the chuck portion 86 supported by the support member 87 is adjusted by moving the support member 87 so that the normal direction of the support member 87 faces the horizontal direction. In the example shown in FIG. 9, the protruding direction Y of the loop portion 81 coincides with the thickness direction of the chuck portion. Further, a load cell 88 is prepared at a position separated from the second chuck 862 by a distance Z1 in the protruding direction Y of the loop portion 81. In this application, the distance Z1 is 50 mm. Subsequently, the load cell 88 is moved toward the loop portion 81 of the test piece 80 by a distance Z2 shown in FIG. 9 at a speed V. The distance Z2 is set so that the load cell 88 comes into contact with the loop portion 81, and then the load cell 88 pushes the loop portion 81 toward the chuck portion 86, as shown in FIGS. 9 and 10. In this application, the distance Z2 was set to 40 mm. In this case, the distance Z3 between the load cell 88 and the second chuck 862 of the chuck part 86 is 10 mm when the load cell 88 is pushing the loop part 81 into the chuck part 86 side. The speed V at which the load cell 88 was moved was 3.3 mm/sec.

Subsequently, as shown in FIG. 10, the load cell 88 is moved toward the chuck part 86 by a distance Z2, and in a state where the load cell 88 is pushing the loop part 81 of the test piece 80, a load is applied from the loop part 81 to the load cell 88. After the load value stabilizes, record the load value. The load value thus obtained is employed as the loop stiffness of the film constituting the test piece 80. In the present application, unless otherwise specified, the environment during loop stiffness measurement is a temperature of 23° C. and a relative humidity of 50%.

Preferred mechanical properties of the high stiffness polyester film will be further explained.
The puncture strength of the high stiffness polyester film is preferably 10N or more, more preferably 11N or more.

The tensile strength of the high stiffness polyester film in at least one direction is preferably at least 250 MPa, more preferably at least 280 MPa. For example, the tensile strength of the high stiffness polyester film in the machine direction is preferably 250 MPa or more, more preferably 280 MPa or more. Further, the tensile strength of the high stiffness polyester film in the vertical direction is preferably 250 MPa or more, more preferably 280 MPa or more.
The tensile elongation of the high stiffness polyester film in at least one direction is preferably 130% or less, more preferably 120% or less. For example, the tensile elongation of the high stiffness polyester film in the machine direction is preferably 130% or less, more preferably 120% or less. Further, the tensile elongation of the high stiffness polyester film in the vertical direction is preferably 120% or less, more preferably 110% or less.
Preferably, the value obtained by dividing the tensile strength of the high stiffness polyester film by the tensile elongation is 2.0 [MPa/%] or more in at least one direction. For example, the value obtained by dividing the tensile strength of a high stiffness polyester film in the vertical direction (TD) by the tensile elongation is preferably 2.0 [MPa/%] or more, more preferably 2.2 [MPa/%]. That's all. The value obtained by dividing the tensile strength of the high stiffness polyester film in the machine direction (MD) by the tensile elongation is preferably 1.8 [MPa/%] or more, more preferably 2.0 [MPa/%] or more. be.
Tensile strength and tensile elongation can be measured in accordance with JIS K7127. As a measuring device, a tensile tester STA-1150 manufactured by Orientech Co., Ltd. can be used. As the test piece, a rectangular film having a width of 15 mm and a length of 150 mm can be used, which is cut from a high stiffness polyester film. The distance between the pair of chucks holding the test piece at the start of the measurement was 100 mm, and the pulling speed was 300 mm/min. In this application, unless otherwise specified, the environment during the measurement of tensile strength and tensile elongation is a temperature of 23° C. and a relative humidity of 50%.
In addition, in the bag 10 shown in FIG. 1, the first direction D1 corresponds to the machine direction (MD) of a film such as the stretched plastic film 60. Further, the second direction D2 corresponds to the vertical direction (TD) of a film such as the stretched plastic film 60.

The heat shrinkage rate of the high stiffness polyester film in at least one direction is preferably 0.7% or less, more preferably 0.5% or less. For example, the heat shrinkage rate of the high stiffness polyester film in the machine direction is preferably 0.7% or less, more preferably 0.5% or less. The heat shrinkage rate of the high stiffness polyester film in the vertical direction is preferably 0.7% or less, more preferably 0.5% or less. The heating temperature when measuring the thermal shrinkage rate was 100° C., and the heating time was 40 minutes.
The tensile modulus of the high stiffness polyester film in at least one direction is preferably 4.0 GPa or higher, more preferably 4.5 MPa or higher. For example, the tensile modulus of the high stiffness polyester film in the machine direction is preferably 4.0 GPa or more, more preferably 4.5 MPa or more. The tensile modulus of the high stiffness polyester film in the vertical direction is preferably 4.0 GPa or more, more preferably 4.5 GPa or more.

In the manufacturing process of high stiffness polyester film, for example, first, a plastic film obtained by melting and molding polyester is heated 3 times to 4.5 times in the machine direction and vertical direction at 90°C to 145°C, respectively. A first stretching process is performed to stretch the film. Subsequently, a second stretching step is performed in which the plastic film is stretched 1.1 to 3.0 times in the machine direction and in the vertical direction at 100° C. to 145° C., respectively. Thereafter, heat fixation is performed at a temperature of 190°C to 220°C. Subsequently, a relaxation treatment (treatment for reducing the film width) of about 0.2% to 2.5% is performed at a temperature of 100° C. to 190° C. in the flow direction and the vertical direction. In these steps, by adjusting the stretching ratio, stretching temperature, heat setting temperature, and relaxation treatment rate, a high stiffness polyester film having the above-mentioned mechanical properties can be obtained.

According to this embodiment, the stiffness of the packaging material 30 can be increased by including the high stiffness polyester film. For example, the loop stiffness of the packaging material 30 per unit thickness of the packaging material 30 can be increased. The value obtained by dividing the loop stiffness of the packaging material 30 in at least one direction by the thickness of the packaging material 30 is, for example, 0.00085 N/μm or more, and may be 0.00090 N/μm or more, and is 0.00095 N/μm. It may be more than 0.00100 N/μm. For example, the value obtained by dividing the loop stiffness of the packaging material 30 in the machine direction (MD) by the thickness of the packaging material 30 is, for example, 0.00085 N/μm or more, and may be 0.00090 N/μm or more, and 0.00085 N/μm or more. It may be 00095 N/μm or more, or it may be 0.00100 N/μm or more. Further, the value obtained by dividing the loop stiffness of the packaging material 30 in the vertical direction (TD) by the thickness of the packaging material 30 is, for example, 0.00080 N/μm or more, and may be 0.00085 N/μm or more, and 0.00080 N/μm or more. It may be 00090 N/μm or more, or 0.00095 N/μm or more.

When the high stiffness polyester film is a high stiffness PET film containing PET as a main component, the PET constituting the high stiffness PET film may include PET derived from biomass. In this case, the high stiffness PET film may be composed only of biomass-derived PET. Alternatively, the high stiffness PET film may be composed of biomass-derived PET and fossil fuel-derived PET. Since high stiffness PET film contains biomass-derived PET, the amount of fossil fuel-derived PET can be reduced compared to conventional methods, which can reduce carbon dioxide emissions and reduce environmental impact. can. Note that biomass-derived PET uses biomass-derived ethylene glycol as a diol unit and fossil fuel-derived terephthalic acid as a dicarboxylic acid unit. Fossil fuel-derived PET uses fossil fuel-derived ethylene glycol as a diol unit and fossil fuel-derived terephthalic acid as a dicarboxylic acid unit.

Carbon dioxide in the atmosphere contains C14 at a certain rate (105.5 pMC), so the C14 content in plants that grow by taking in atmospheric carbon dioxide, such as corn, is also around 105.5 pMC. It is known. It is also known that fossil fuels contain almost no C14. Therefore, by measuring the proportion of C14 contained in all carbon atoms in PET, the proportion of carbon derived from biomass can be calculated. In the present invention, "biomass degree" indicates the weight ratio of biomass-derived components. Taking PET as an example, PET is a product obtained by polymerizing ethylene glycol containing 2 carbon atoms and terephthalic acid containing 8 carbon atoms in a molar ratio of 1:1. When only biomass-derived ethylene glycol is used as ethylene glycol for PET, the weight ratio of biomass-derived components in PET is 31.25%, so the theoretical value of the biomass degree of PET is 31.25%. Specifically, the mass of PET is 192, of which the mass derived from biomass-derived ethylene glycol is 60, so 60÷192×100=31.25. Furthermore, the weight ratio of biomass-derived components in fossil fuel-derived PET is 0%, and the biomass content of fossil fuel-derived PET is 0%. In the present invention, the biomass degree of the high stiffness PET film is preferably 5.0% or more, more preferably 10.0% or more. Further, the biomass degree of the high stiffness PET film is preferably 30.0% or less.

Biomass-derived ethylene glycol is made from ethanol produced from biomass (biomass ethanol). For example, biomass-derived ethylene glycol can be obtained by converting biomass ethanol into ethylene glycol via ethylene oxide using a conventionally known method. Raw materials for biomass ethanol include corn, sugar cane, beets, and manioc. Moreover, commercially available biomass ethylene glycol may be used, and for example, biomass ethylene glycol commercially available from India Glycol Corporation can be suitably used. Incidentally, India Glycol's biomass ethylene glycol is made from sugarcane molasses.

(adhesive layer)
Adhesive layer 65 includes an adhesive for bonding stretched plastic film 60 and sealant layer 70 together by dry lamination. The adhesive constituting the adhesive layer 65 is produced from an adhesive composition prepared by mixing a first composition containing a base agent and a solvent and a second composition containing a curing agent and a solvent. Specifically, the adhesive includes a cured product produced by a reaction between the base agent and the solvent in the adhesive composition.

Examples of adhesives include polyurethane. Polyurethane is a cured product produced by the reaction of a polyol as a main ingredient and an isocyanate compound as a curing agent. Examples of polyurethane include polyether polyurethane, polyester polyurethane, and the like. Polyether polyurethane is a cured product produced by the reaction of a polyether polyol as a main ingredient and an isocyanate compound as a curing agent. Polyester polyurethane is a cured product produced by the reaction of a polyester polyol as a main ingredient and an isocyanate compound as a curing agent.

Isocyanate compounds include aromatic isocyanate compounds such as tolylene diisocyanate (TDI), 4,4'-diphenylmethane diisocyanate (MDI), xylylene diisocyanate (XDI), hexamethylene diisocyanate (HDI), isophorone diisocyanate (IPDI), etc. or adducts or multimers of the various isocyanate compounds mentioned above can be used.

As mentioned above, aromatic isocyanate compounds and aliphatic isocyanate compounds exist as isocyanate compounds constituting the curing agent of the adhesive. Among these, aromatic isocyanate compounds elute components that cannot be used in food applications in high-temperature environments such as heat sterilization. By the way, the adhesive layer 65 is in contact with the sealant layer 70. Therefore, when the adhesive layer 65 contains an aromatic isocyanate compound, components eluted from the aromatic isocyanate compound may adhere to the contents stored in the storage portion 17 in contact with the sealant layer 70. .

In consideration of such problems, it is preferable to use a cured product produced by the reaction of a polyol as a main ingredient and an aliphatic isocyanate compound as a curing agent as the adhesive constituting the adhesive layer 65. . This can prevent components that cannot be used in food applications caused by the adhesive layer 65 from adhering to the contents.

The material making up adhesive layer 65 preferably has a higher thermal conductivity than the material making up stretched plastic film 60. For example, the thermal conductivity of the material constituting the adhesive layer 65 is preferably 1.0 W/m·K or more, more preferably 3.0 W/m·K or more. Note that the thermal conductivity of polyurethane is within the range of 3.0 W/m·K to 5.0 W/m·K, for example, 5.0 W/m·K. Due to the high thermal conductivity of the material constituting the adhesive layer 65, when the bag 10 made using the packaging material 30 is heated, the heat generated in the storage section 17 is transferred from the inner surface 30x side of the packaging material 30. The heat is easily diffused in the surface direction of the packaging material 30 while being transferred to the outer surface 30y side. Thereby, the heat dissipation of the packaging material 30 can be improved, so that a rise in the temperature of the packaging material 30 can be suppressed. This can prevent the packaging material 30 from being damaged by heat when the bag 10 is heated. That is, the heat resistance of the packaging material 30 can be improved.

The thickness of the adhesive layer 65 is preferably 2 μm or more, more preferably 3 μm or more. Further, the thickness of the adhesive layer 65 is preferably 6 μm or less, more preferably 5 μm or less. By setting the thickness of the adhesive layer 65 to 3 μm or more, heat diffusion in the surface direction of the packaging material 30 is more likely to occur.

(Sealant layer)
Next, the sealant layer 70 will be explained. As the material constituting the sealant layer 70, one or more resins selected from polyethylene such as low-density polyethylene, linear low-density polyethylene, and polypropylene can be used. The sealant layer 70 may be a single layer or a multilayer. Further, the sealant layer 70 is preferably made of an unstretched sealant film. Note that "unstretched" is a concept that includes not only a film that has not been stretched at all, but also a film that has been slightly stretched due to the tension applied during film formation.

The sealant film constituting the sealant layer 70 is, for example, a plastic film that has been stretched to a degree necessary for transportation, but not intentionally stretched. Preferred mechanical properties of the sealant film will be further explained.
The tensile modulus of the sealant film in at least one direction is preferably 1000 MPa or less. For example, the tensile modulus of the sealant film in the machine direction and in the vertical direction is preferably 1000 MPa or less.
The tensile elongation of the sealant film in at least one direction is preferably 300% or more. For example, the tensile elongation of the sealant film in the machine direction and the vertical direction is preferably 300% or more.

The tensile modulus and tensile elongation of the sealant film can be measured in accordance with JIS K7127 as in the case of the high stiffness polyester film. As a measuring device, a tensile tester STA-1150 manufactured by Orientech Co., Ltd. can be used. As the test piece, a rectangular film having a width of 15 mm and a length of 150 mm can be used. The distance between the pair of chucks holding the test piece at the start of the measurement was 100 mm, and the pulling speed was 300 mm/min.

The bag 10 made of the packaging material 30 may be subjected to sterilization treatment such as boiling treatment or retort treatment at high temperatures. Sealant layer 70 preferably has heat resistance to withstand processing at these high temperatures. Note that the retort process is a process in which the contents are filled into the bag 10, the bag 10 is sealed, and then the bag 10 is heated under pressure using steam or heated hot water.
The temperature of the retort treatment is, for example, 120° C. or higher. The boiling process is a process of filling the bag 10 with contents, sealing the bag 10, and then boiling the bag 10 in hot water under atmospheric pressure. The temperature of the boiling treatment is, for example, 90°C or higher and 100°C or lower.

The melting point of the material constituting the sealant layer 70 is preferably 150°C or higher, more preferably 160°C or higher. By increasing the melting point of the sealant layer 70, it becomes possible to retort the bag 10 at a high temperature, thereby shortening the time required for the retort treatment. Note that the melting point of the material constituting the sealant layer 70 is lower than the melting point of the resin constituting the stretched plastic film 60.

When considering from the viewpoint of retort processing, a material containing propylene as a main component can be used as the material constituting the sealant layer 70. Here, the material "having propylene as a main component" means a material having a propylene content of 90% by mass or more. Specific examples of materials containing propylene as a main component include polypropylene such as propylene/ethylene block copolymer, propylene/ethylene random copolymer, homopolypropylene, or a mixture of polypropylene and polyethylene. I can do it. Here, "propylene/ethylene block copolymer" means a material having the structural formula shown in the following formula (I). Moreover, "propylene/ethylene random copolymer" means a material having a structural formula shown in the following formula (II). Moreover, "homopolypropylene" means a material having a structural formula shown in the following formula (III).

When a mixture of polypropylene and polyethylene is used as the material whose main component is propylene, the material may have a sea-island structure. Here, the "sea-island structure" refers to a structure in which polyethylene is discontinuously dispersed within a continuous region of polypropylene.

When considered from the viewpoint of boiling processing, examples of the material constituting the sealant layer 70 include polyethylene, polypropylene, or a combination thereof. Examples of polyethylene include medium density polyethylene, linear low density polyethylene, and combinations thereof. For example, it is also possible to use the materials listed as the materials constituting the sealant layer 70 from the viewpoint of the above-mentioned retort processing. The material constituting the sealant layer 70 has a melting point of, for example, 100°C or higher, more preferably 105°C or higher, more preferably 110°C or higher, still more preferably 115°C or higher. When polyethylene is used as the material constituting the sealant layer 70, a melting point of 100° C. or higher can be achieved, for example, when the density of the polyethylene is 0.920 g/cm ³ or higher. Specific examples of the sealant layer for forming the sealant layer 70 having a melting point of 100° C. or higher include TUX-HC manufactured by Mitsui Chemicals Tohcello, L6101 manufactured by Toyobo, and LS700C manufactured by Idemitsu Unitec. A specific example of the sealant layer for configuring the sealant layer 70 having a melting point of 105° C. or higher includes NB-1 manufactured by Tamapori. Specific examples of the sealant layer for constituting the sealant layer 70 having a melting point of 110° C. or higher include LS760C manufactured by Idemitsu Unitech, TUX-HZ manufactured by Mitsui Chemicals Tohcello, and the like.

Preferably, sealant layer 70 is a single layer film comprising a propylene-ethylene block copolymer. For example, the sealant layer including the sealant layer 70 is a single-layer unstretched film containing a propylene/ethylene block copolymer as a main component.
By using the propylene/ethylene block copolymer, the impact resistance of the sealant layer can be increased, and thereby the bag 10 can be prevented from being torn due to impact when dropped. Moreover, the puncture resistance of the packaging material 30 can be improved.

The propylene/ethylene block copolymer includes, for example, a sea component made of polypropylene and an island component made of an ethylene/propylene copolymer rubber component. The sea component can contribute to increasing the blocking resistance, heat resistance, rigidity, seal strength, etc. of the propylene/ethylene block copolymer. Additionally, the island component can contribute to increasing the impact resistance of the propylene/ethylene block copolymer. Therefore, by adjusting the ratio of the sea component to the island component, the mechanical properties of the sealant layer containing the propylene/ethylene block copolymer can be adjusted.

In the propylene/ethylene block copolymer, the mass ratio of the sea component made of polypropylene is higher than the mass ratio of the island component made of the ethylene/propylene copolymer rubber component. For example, in a propylene/ethylene block copolymer, the mass ratio of the sea component made of polypropylene is at least 51% by mass or more, preferably 60% by mass or more, and more preferably 70% by mass or more.

The single-layer sealant layer may further contain a second thermoplastic resin in addition to the first thermoplastic resin made of a propylene/ethylene block copolymer. Examples of the second thermoplastic resin include α-olefin copolymers and polyethylene. The α-olefin copolymer is, for example, linear low density polyethylene. Examples of polyethylene include low density polyethylene, medium density polyethylene, and high density polyethylene. The second thermoplastic resin may contribute to increasing the impact resistance of the sealant layer.

Low-density polyethylene is polyethylene with a density of 0.910 g/cm ³ or more and 0.925 g/cm ³ or less. Medium density polyethylene is polyethylene with a density of 0.926 g/cm ³ or more and 0.940 g/cm ³ or less. High-density polyethylene is polyethylene with a density of 0.941 g/cm ³ or more and 0.965 g/cm ³ or less. Low-density polyethylene is obtained, for example, by polymerizing ethylene at a high pressure of 1000 atm or more and less than 2000 atm. Medium-density polyethylene and high-density polyethylene are obtained, for example, by polymerizing ethylene at medium or low pressures of 1 atm or more and less than 1000 atm.

Note that the medium density polyethylene and high density polyethylene may partially contain a copolymer of ethylene and α-olefin. Furthermore, even when ethylene is polymerized at medium or low pressure, polyethylene of medium density or low density can be produced if a copolymer of ethylene and α-olefin is included. Such polyethylene is referred to as the above-mentioned linear low density polyethylene. Linear low-density polyethylene is obtained by copolymerizing α-olefin into a linear polymer obtained by polymerizing ethylene at medium or low pressure to introduce short chain branches. Examples of α-olefins include 1-butene (C ₄ ), 1-hexene (C ₆ ), 4-methylpentene (C ₆ ), 1-octene (C ₈ ), and the like. The density of the linear low density polyethylene is, for example, 0.915 g/cm ³ or more and 0.945 g/cm ³ or less.

Note that the α-olefin copolymer constituting the second thermoplastic resin of the propylene/ethylene block copolymer is not limited to the above-mentioned linear low-density polyethylene. The α-olefin copolymer means a material having the structural formula shown in the following formula (IV).

Both R ₁ and R ₂ are H (hydrogen atom) or an alkyl group such as CH ₃ or C ₂ H ₅ . Further, both j and k are integers of 1 or more. Also, j is larger than k. That is, in the α-olefin copolymer shown in formula (IV), the structure on the left containing R ₁ is the base. R ₁ is, for example, H and R ₂ is, for example, C ₂ H ₅ .

In the sealant layer, the mass ratio of the first thermoplastic resin comprising a propylene/ethylene block copolymer is higher than the mass ratio of the second thermoplastic resin comprising at least an α-olefin copolymer or polyethylene. For example, in a single sealant layer, the mass ratio of the first thermoplastic resin made of a propylene/ethylene block copolymer is at least 51% by mass, preferably 60% by mass or more, and more preferably 70% by mass. % by mass or more.

As mentioned above, the second thermoplastic resin can contribute to increasing the impact resistance of the sealant layer. Therefore, by adjusting the mass ratio of the second thermoplastic resin containing at least an α-olefin copolymer or polyethylene in the single sealant layer, the mechanical properties of the sealant layer can be adjusted.

Moreover, the sealant layer 70 may further contain a thermoplastic elastomer. By using a thermoplastic elastomer, the impact resistance and puncture resistance of the sealant layer 70 can be further improved.

The thermoplastic elastomer is, for example, a hydrogenated styrene thermoplastic elastomer. The hydrogenated styrenic thermoplastic elastomer has a structure consisting of a polymer block A mainly composed of at least one vinyl aromatic compound and a polymer block B mainly composed of at least one hydrogenated conjugated diene compound. . Further, the thermoplastic elastomer may be an ethylene/α-olefin elastomer. Ethylene/α-olefin elastomer is a low-crystalline or amorphous copolymer elastomer, and is a random copolymer of 50 to 90% by mass of ethylene as the main component and α-olefin as a comonomer. be.

Moreover, the sealant layer 70 may further contain a crystallization promoter. By using a crystallization promoter, the tensile modulus of the sealant layer 70 can be increased. Thereby, the tearability of the sealant layer 70 and the packaging material 30 can be improved. Examples of the crystal accelerator include phosphoric acid ester metal salts and benzoic acid metal salts.

The content of the propylene/ethylene block copolymer in the sealant layer 70 is, for example, 80% by mass or more, preferably 90% by mass or more.

A method for producing a propylene/ethylene block copolymer includes a method of polymerizing raw materials such as propylene and ethylene using a catalyst. As the catalyst, a Ziegler-Natta type catalyst, a metallocene catalyst, or the like can be used.

The thickness of the sealant layer 70 is preferably 30 μm or more, more preferably 40 μm or more. Further, the thickness of the sealant layer 70 is preferably 100 μm or less, more preferably 80 μm or less.

Hereinafter, preferred mechanical properties of the sealant film when the sealant layer 70 is a single layer sealant film containing a propylene/ethylene block copolymer will be described.
The tensile elongation of the sealant film at 25° C. in the machine direction (MD) is preferably 600% or more and 1300% or less. Further, the product of the tensile elongation (%) of the sealant film in the machine direction (MD) and the thickness (μm) of the sealant film is preferably 35,000 or more and 80,000 or less. Further, the tensile elongation of the sealant film at 25° C. in the vertical direction (TD) is preferably 700% or more and 1400% or less. Further, the product of the tensile elongation (%) of the sealant film in the vertical direction (TD) and the thickness (μm) of the sealant film is preferably 40,000 or more and 85,000 or less.
The tensile modulus of the sealant film at 25° C. in the machine direction (MD) is preferably 400 MPa or more and 1100 MPa or less. Further, the product of the tensile modulus (MPa) of the sealant film in the machine direction (MD) and the thickness (μm) of the sealant film is preferably 30,000 or more and 55,000 or less. Further, the tensile modulus of the sealant film in the vertical direction (TD) at 25° C. is preferably 250 MPa or more and 900 MPa or less. Further, the product of the tensile modulus (MPa) of the sealant film in the vertical direction (TD) and the thickness (μm) of the sealant film is preferably 20,000 or more and 45,000 or more.
In addition, in the bag 10 shown in FIG. 1, the first direction D1 corresponds to the flow direction (MD) of the sealant film. Further, the second direction D2 corresponds to the vertical direction (TD) of the sealant film.

Tensile modulus and tensile elongation can be measured in accordance with JIS K7127. As a measuring device, a tensile tester STA-1150 manufactured by Orientech Co., Ltd. can be used. In the bag 10 shown in FIG. 1, the direction in which the upper part 11 and the lower part 12 extend is the flow direction of the film constituting the bag 10, such as a sealant film, and the direction in which the side part 13 extends is the direction in which the film such as the sealant film flows. , which is the vertical direction of the film constituting the bag 10. Although not shown, the bag 10 may be configured such that the direction in which the upper part 11 and the lower part 12 extend is the perpendicular direction of the film, and the direction in which the side parts 13 extend is the direction in which the film flows.

There are two main types of single-layer sealant films containing propylene/ethylene block copolymers.
The first type is a type having high tensile elongation and impact resistance, such as unstretched polypropylene film ZK500 manufactured by Toray Film Processing Co., Ltd. The first type of sealant film preferably also has the characteristic of low hot seal strength. Thereby, it is possible to suppress the internal pressure of the accommodating part 17 from becoming excessive when the bag 10 is heated, and it is possible to suppress the packaging material 30 from being damaged.
The second type is a type having a high tensile modulus, such as unstretched polypropylene films ZK207 and ZK500R manufactured by Toray Film Processing Co., Ltd. By using the second type of sealant film, tearability when the consumer opens the bag 10 by tearing the bag 10 along the first direction D1 can be improved.

The product of the tensile elongation (%) of the first type of sealant film in the machine direction (MD) and the thickness (μm) of the sealant film is preferably 45,000 or more, more preferably 50,000 or more, 55,000 or more, Or it may be 60,000 or more. Further, the product of the tensile elongation (%) of the first type sealant film in the vertical direction (TD) and the thickness (μm) of the sealant film is preferably 53,000 or more, more preferably 60,000 or more. By having a high tensile elongation of the sealant film, it is possible to suppress the bag 10 from being torn due to impact when dropped or the like.
Further, the product of the tensile modulus (MPa) of the first type sealant film in the machine direction (MD) and the thickness (μm) of the sealant film is preferably 38,000 or less, more preferably 35,000 or less. Further, the product of the tensile modulus (MPa) of the first type sealant film in the vertical direction (TD) and the thickness (μm) of the sealant film is preferably 30,000 or less, more preferably 25,000 or less.

The product of the tensile modulus (MPa) of the second type of sealant film in the machine direction (MD) and the thickness (μm) of the sealant film is preferably 35,000 or more, 38,000 or more, 42,000 or more, 45,000 or more, or 48,000 or more. It may be more than that. From the viewpoint of tearability, in particular, propylene-ethylene block copolymers that have a tensile modulus (MPa) in the machine direction (MD) of 800 MPa or more when the thickness of the single-layer sealant layer 70 is 50 μm. It is preferable to use a material containing
Further, the product of the tensile modulus (MPa) of the second type sealant film in the vertical direction (TD) and the thickness (μm) of the sealant film is preferably 25,000 or more, 30,000 or more, 35,000 or more, or 38,000 or more. It may be. From the viewpoint of tearability, in particular, a propylene/ethylene block copolymer that has a tensile modulus (MPa) in the vertical direction (TD) of 650 MPa or more when the thickness of the single-layer sealant layer 70 is 50 μm. It is preferable to use a material containing
Since the sealant film has a high tensile modulus, tearability when opening the bag 10 can be improved.
Further, the product of the tensile elongation (%) of the second type sealant film in the machine direction (MD) and the thickness (μm) of the sealant film is preferably 55,000 or less, more preferably 50,000 or less. Further, the product of the tensile elongation (%) of the second type sealant film in the vertical direction (TD) and the thickness (μm) of the sealant film is preferably 60,000 or less, more preferably 55,000 or less.

The sealant layer 70 may have easy-peel properties. Easy-peel property refers to the fact that, for example, when the packaging material 30 having the sealant layer 70 is used to construct the lid of a container, the lid is likely to peel off from the flange of the container at its lower surface, that is, at the sealant layer 70. It is a characteristic. Easy peelability can be achieved, for example, by forming the sealant layer 70 with two or more types of resin and making one resin incompatible with the other resin. Examples of resins that can exhibit easy-peel properties include mixed resins of polyethylene and polypropylene, such as high-density polyethylene.

When the sealant layer 70 has easy-peel properties, as shown in FIG. A second layer 72 that constitutes the inner surface 30x of 30 may also be included. As the first layer 71 and second layer 72 of the sealant layer 70 having easy-peel properties, there are mainly two types, such as type A and type B described below.

In the A-type sealant layer 70, the first layer 71 is a layer containing polyethylene as a main component, and the second layer 72 is a layer containing a mixed resin of polyethylene and polypropylene. In the second layer 72, the blending ratio of polypropylene is greater than the blending ratio of polyethylene. The mass ratio of polypropylene to polyethylene in the second layer 72 is 6:4 to 8:2.

When the packaging material 30 provided with the A-type sealant layer 70 is used in a packaging product for heat sterilization, it is preferable that the density of polyethylene in the sealant layer 70 is 0.940 g/cm ³ or more.

As the polypropylene in the second layer 72 of the A-type sealant layer 70, for example, an ethylene-propylene random copolymer can be used.

In the A-type sealant layer 70, the ratio of the thickness of the first layer 71 to the thickness of the second layer 72 can be 5:1 to 10:1.

In the B type sealant layer 70, the first layer 71 is a layer containing polypropylene as a main component, and the second layer 72 is a layer containing a mixed resin of polyethylene and polypropylene. In the second layer 72, the blending ratio of polypropylene is greater than the blending ratio of polyethylene. The mass ratio of polypropylene to polyethylene in the second layer 72 is 6:4 to 8:2.

When the packaging material 30 provided with the B-type sealant layer 70 is used in a packaging product for heat sterilization, it is preferable that the density of the polyethylene in the sealant layer 70 is 0.940 g/cm ³ or more.

As the polypropylene in the first layer 71 of the B-type sealant layer 70, for example, an ethylene-propylene block copolymer can be used. As the polypropylene in the second layer 72 of the B-type sealant layer 70, for example, an ethylene-propylene random copolymer can be used.

In the B type sealant layer 70, the ratio of the thickness of the first layer 71 to the thickness of the second layer 72 can be 3:1 to 8:1.

Note that the sealant layer 70 may be a resin layer provided on the inner surface of the stretched plastic film 60 by an extrusion method or the like. In this case, the above-described adhesive layer 65 may not be present between the stretched plastic film 60 and the sealant layer 70.

(Other layers)
As shown in FIG. 2, the packaging material 30 may further include a printed layer 36 provided on the stretched plastic film 60. The printing layer 36 is a layer for indicating information on the contents and the packaged product, and for imparting aesthetic appeal to the packaged product such as the bag 10. The printing layer expresses characters, numbers, symbols, figures, patterns, etc. As the material constituting the printing layer, ink for gravure printing or ink for flexographic printing can be used. A specific example of the ink for gravure printing is Finart manufactured by DIC Graphics Corporation.

FIG. 3 is a sectional view showing a modified example of the layer structure of the packaging material 30. As shown in FIG. 3, the packaging material 30 may further include a vapor deposition layer 37 located on the inner surface 30x side of the stretched plastic film 60. Moreover, the packaging material 30 may further include a gas barrier coating film 38 located on the surface of the vapor deposition layer 37 and having transparency.

The vapor deposition layer 37 and the gas barrier coating film 38 will be explained below.

The vapor deposition layer 37 is a layer provided on the packaging material 30 in order to improve the gas barrier properties of the packaging material 30. As a material constituting the vapor deposition layer 37, metal such as aluminum can be used. Further, the vapor deposition layer 37 may be a transparent vapor deposition layer formed of a transparent inorganic material such as aluminum oxide (aluminum oxide) or silicon oxide. In particular, when the printing layer 36 is provided closer to the inner surface 30x than the vapor deposition layer 37, the vapor deposition layer 37 is configured as a transparent vapor deposition layer.

The vapor deposited layer 37 functions as a layer having a gas barrier function that prevents permeation of oxygen gas, water vapor, and the like. Note that two or more vapor deposited layers 37 may be provided. When there are two or more vapor deposited layers 37, they may each have the same composition or different compositions. As a method for forming the vapor deposition layer 37, for example, a physical vapor deposition method (PVD method) such as a vacuum evaporation method, a sputtering method, and an ion plating method, a plasma chemical vapor deposition method, or a thermal vapor deposition method can be used. Examples include chemical vapor deposition methods (Chemical Vapor Deposition methods, CVD methods) such as chemical vapor deposition methods and photochemical vapor deposition methods. Specifically, a vapor deposition layer can be formed on a film forming roller using a roller type vapor deposition film forming apparatus. The thickness of the vapor deposition layer 37 is, for example, 20 Å or more and 200 Å, preferably 30 Å or more and 150 Å, and more preferably 50 Å or more and 120 Å or less. Note that the thickness of the vapor deposited layer 37 can be measured by a fundamental parameter method using, for example, a fluorescent X-ray analyzer (product name: RIX2000 model, manufactured by Rigaku Corporation).

The gas barrier coating film 38 is a layer that functions as a layer that suppresses permeation of oxygen gas, water vapor, and the like. The gas barrier coating film 38 has a general formula R ¹ _n M(OR ² ) _m (wherein R ¹ and R ² represent an organic group having 1 to 8 carbon atoms, M represents a metal atom, n represents an integer of 0 or more, m represents an integer of 1 or more, and n+m represents the valence of M.) and at least one alkoxide represented by the above-mentioned polyvinyl alcohol. system resin and/or ethylene/vinyl alcohol copolymer, and further polycondensed by a sol-gel method in the presence of a sol-gel method catalyst, acid, water, and an organic solvent. It will be done. Note that the gas barrier coating film 38 is preferably transparent.

Layer Structure of Lower Film Next, the layer structure of the lower film 16 will be explained.

The layer structure of the lower film 16 is arbitrary as long as it has an inner surface that can be joined to the inner surface of the front film 14 and the inner surface of the back film 15. For example, similar to the front film 14 and the back film 15, the above-mentioned packaging material 30 may be used as the lower film 16. Alternatively, a film whose inner surface is composed of a sealant layer and whose structure is different from that of the packaging material 30 may be used as the lower film 16.

Method for manufacturing packaging material Next, an example of a method for manufacturing the packaging material 30 will be described.

First, the above-mentioned stretched plastic film 60 and sealant layer 70 are prepared. The stretched plastic film 60 is provided with a printed layer 36, a vapor deposition layer 37, a gas barrier coating film 38, etc., as necessary.

Subsequently, the stretched plastic film 60 and the sealant layer 70 are laminated with the adhesive layer 65 interposed therebetween by a dry lamination method. Thereby, a packaging material 30 comprising a stretched plastic film 60 and a sealant layer 70 can be obtained.

In the dry lamination method, first, an adhesive composition is applied to one of the two films to be laminated. Subsequently, the applied adhesive composition is dried to evaporate the solvent. Thereafter, the two films are laminated via the dried adhesive composition. Subsequently, the two laminated films are rolled up and aged for 24 hours or more in an environment of 20° C. or higher, for example.

Method for manufacturing bag Next, a method for manufacturing bag 10 using the above-mentioned packaging material 30 will be explained. First, a front film 14 and a back film 15 made of packaging material 30 are prepared. Further, a folded lower film 16 is inserted between the front film 14 and the back film 15. Subsequently, the inner surfaces of each film are heat-sealed to form seal parts such as the lower seal part 12a and the side seal part 13a. Further, the films bonded together by heat sealing are cut into an appropriate shape to obtain the bag 10 shown in FIG. 1.

Subsequently, the contents 18 are filled into the bag 10 through the opening 11b of the upper part 11. Specifically, as shown in FIG. 12, a portion of the pair of side seal portions 13a of the bag 10 near the top 11 is gripped by a pair of chuck portions 105. Further, as shown by arrow P in FIG. 12, the chuck portions 105 are moved in a direction in which the distance between the pair of chuck portions 105 becomes narrower in the width direction of the bag 10. Thereby, the front film 14 and the back film 15 are deformed so as to form the opening 11b in the upper part 11. At this time, as shown in FIG. 12, a suction part 106 may be attached to the outer surface of the front film 14 and the back film 15, and the suction part 106 may be moved in the direction of arrow Q. This makes it easier to form the opening 11b. Subsequently, the contents 18 are filled into the bag 10 through the opening 11b. Thereafter, the upper portion 11 is heat-sealed to form an upper sealed portion 11a. In this way, a sealed bag 10 containing the contents 18 can be obtained.

The content 18 is, for example, a cooked food containing water, such as curry, stew, or soup. Furthermore, the contents 18 may include materials containing a large amount of oil, such as meat, fish, and seasonings for them. In addition to foods, the bag 10 can also contain items that can be heated by boiling water or the like. Further, the bag 10 may contain contents that do not require heating.

In this embodiment, a high stiffness polyester film is used as the stretched plastic film 60 of the packaging material 30 constituting the bag 10. Therefore, the packaging material 30 and the bag 10 can have rigidity and puncture resistance. This can prevent the bag 10 from tearing, for example, when a sharp member with a pointed tip comes into contact with the bag 10. The puncture strength of the packaging material 30 is preferably 12N or more, more preferably 13N or more. A method for measuring puncture strength will be explained in Examples described later.

Further, in this embodiment, since the packaging material 30 constituting the front film 14 and the back film 15 has rigidity, when moving the chuck part 105 as shown in FIG. It becomes easier to form. For example, the front film 14 and the back film 15 are each easily deformed to have a curved shape that is convex toward the outer surface. This makes it easier to ensure the opening width K of the opening 11b. Moreover, in this embodiment, since the packaging material 30 that constitutes the front film 14 and the back film 15 has rigidity, wrinkles are not likely to occur in the front film 14 and the back film 15. Therefore, the suction portion 106 is easily adsorbed to the outer surfaces of the front film 14 and the back film 15. This can also contribute to securing the opening width K of the opening 11b.

Method for opening the bag Next, a method for opening the bag 10 will be explained. The consumer opens the bag 10 by tearing the bag 10 along the first direction D1. In this case, it is preferable that the sealant layer 70 of the packaging material 30 constituting the bag 10 has a high tensile modulus. For example, it is preferable to use the second type of sealant layer 70 described above. Thereby, the packaging material 30 and the bag 10 can be made tearable. Therefore, for example, when a consumer tears the bag 10 to open it, it is possible to prevent the tearing direction from deviating from the first direction D1.

(Modified example)
Note that various changes can be made to each of the embodiments described above. Modifications will be described below with reference to the drawings as necessary. In the following description and the drawings used in the following description, the same reference numerals as those used for corresponding parts in each of the above-described embodiments are used for parts that can be configured in the same manner as in each of the above-described embodiments. and omit duplicate explanations. Furthermore, if it is clear that the effects obtained in each of the embodiments described above can also be obtained in the modified example, the explanation thereof may be omitted.

(Modified example of bag)
FIG. 13 is a diagram showing another example of the bag 10 including the packaging material 30. The bag 10 shown in FIG. 13 differs only in that it further includes a steam release mechanism 20, and the other configurations are substantially the same as the bag 10 shown in FIG. 1. In the bag 10 shown in FIG. 13, the same parts as the bag 10 shown in FIG.

As shown in FIG. 13, the bag 10 includes a steam release mechanism 20 for releasing steam generated when heating the contents stored in the storage section 17 to the outside. The steam venting mechanism 20 communicates the inside and outside of the bag 10 to release steam when the pressure of the steam exceeds a predetermined value, and prevents steam from escaping from locations other than the steam venting mechanism 20. ,It is configured.

Note that when the bag 10 equipped with the steam venting mechanism 20 is heated using a microwave oven or the like, the pressure inside the bag 10 may not rise to the extent that steam escapes from the steam venting mechanism 20 to the outside. That is, depending on how the bag 10 is used, the probability that the steam release mechanism 20 will perform the function of releasing steam to the outside may be low. Even in this case, by providing the steam venting mechanism 20 in the bag 10, it is possible to further reduce the probability that steam will escape from a location other than the steam venting mechanism 20 or that the bag 10 will burst.

In the example shown in FIG. 13, the steam venting mechanism 20 includes a steam venting seal portion 20a that protrudes toward the inside of the bag 10 from the side seal portion 13a, and a non-sealed portion separated from the storage portion 17 by the steam venting seal portion 20a. It has a section 20b. The non-sealed portion 20b communicates with the outside of the bag 10. When the pressure in the accommodating portion 17 increases due to heating with a microwave oven or the like, the steam release seal portion 20a peels off. The steam in the accommodating part 17 can escape to the outside of the bag 10 through the peeled part of the steam release seal part 20a and the non-seal part 20b. At this time, since the packaging material 30 has heat resistance, it is possible to suppress the formation of holes in the packaging material 30 or the formation of wrinkles in the packaging material 30 during heating.

Note that the configuration of the steam venting mechanism 20 is not limited to the configuration shown in FIG. 13. The structure of the steam venting mechanism 20 is arbitrary as long as it can communicate the storage part 17 with the outside of the bag 10 when the pressure of steam reaches a predetermined value or higher.

For example, as shown in FIG. 14, the surface film 14 may include a folded palm portion 14a in which the inner surfaces of the surface film 14 are partially overlapped. The palm-to-face portion 14a may be configured, for example, by folding one surface film 14 back at a folding portion 14f to form pleats. Moreover, the palms together part 14a may be formed by partially overlapping two surface films 14.

A palm-to-palm seal portion 14b extending from one side seal portion 13a to the other side seal portion 13a is formed in the palm-to-approach portion 14a. In this case, the steam venting mechanism 20 includes, for example, a steam venting seal portion 20a that protrudes from the palms-up seal portion 14b toward the accommodating portion 17, and a non-sealed portion 20b surrounded by the steam-release seal portion 20a and the palms-pasting seal portion 14b. and a through hole 20c formed in the surface film 14 in the non-sealed portion 20b.

Also in this modification, when the pressure in the accommodation section 17 increases, the steam release seal section 20a peels off, and the accommodation section 17 and the non-sealed section 20b communicate with each other. The steam that has flowed from the accommodating part 17 into the non-sealed part 20b through the peeled part of the steam release seal part 20a escapes to the outside of the bag 10 through the through hole 20c.

Note that the bag 10 shown in FIG. 14 is placed in a microwave oven so that the back film 15 is in wide contact with the turntable or lower surface (flat table) of the microwave oven. Therefore, compared to a self-supporting bag 10 as shown in FIG. 13, the contents are more likely to be heated uniformly. Further, since the area of the portion of the bag 10 in contact with the microwave oven is large, even if the bag 10 is softened by heating, the position of the liquid level of the contents is unlikely to change. For this reason, in the heating step using a microwave oven, a situation in which the contents adhere to the inner surface of the front film 14 or the back film 15 above the liquid level of the contents is unlikely to occur. Thereby, it is possible to suppress the occurrence of a phenomenon in which the contents adhering to the inner surface of the front film 14 or the back film 15 are excessively heated and holes are formed in the front film 14 or the back film 15.

15A and 15B are a longitudinal cross-sectional view and a plan view showing a lidded container 110, which is an example of the use of the packaging material 30. The lidded container 110 includes a container body 112 made by sheet forming such as drawing or injection molding, and a lid member 114 joined to the container body 112. The container body 112 has a bottom surface 112a, a side surface 112b, and a flange portion 113 that extends horizontally outward from the upper end of the side surface 112b. The lid member 114 is joined to the upper surface of the flange portion 113 of the container body 112 via a seal portion 116. The lidding material 114 may include the packaging material 30 described above having a high stiffness polyester film. By constructing the lid material 114 using the above-mentioned packaging material 30, the lid material 114 can have excellent puncture strength. This can prevent the lid 114 from being torn if a sharp member with a pointed tip comes into contact with the lid 114. Furthermore, it is possible to prevent the lidded container 110 from being damaged and the contents to leak out if the lidded container 110 is dropped.

The sealant layer 70 of the packaging material 30 constituting the lid material 114 may have easy-peel properties. That is, the sealant layer 70 of the packaging material 30 constituting the lid material 114 includes a first layer 71 mainly composed of polyethylene or polypropylene, and a second layer 72 containing a mixed resin of polyethylene and polypropylene and constituting the inner surface 30x. , may have.

In this application, products for packaging articles, such as the bag 10 and the lidded container 110, are also referred to as packaging products.

In the packaging material 30 used in a packaged product equipped with the steam release mechanism 20, the strength of the seal portion formed by the sealant layer 70 (hereinafter also referred to as hot seal strength) at high temperatures, for example, 100° C. or higher, is , it is preferable that the sealing strength be extremely small compared to the sealing strength at low temperatures, for example at room temperature. For example, it is preferable that the hot seal strength at 100° C. be one-third or less, preferably one-quarter or less, of the seal strength at 25° C. (hereinafter also referred to as room-temperature seal strength). For example, the hot sealing strength in a width of 15 mm at 100° C. is 30 N or less, preferably 25 N or less, more preferably 20 N or less, even more preferably 15 N or less. Further, the room temperature sealing strength at 25° C. in a width of 15 mm is 23 N or more, preferably 40 N or more, more preferably 50 N or more, and even more preferably 60 N or more. Due to the low hot sealing strength, when the bag 10 equipped with the steam venting mechanism 20 is heated using a microwave oven, the steam venting seal portion 20a is likely to peel off, and the steam in the storage portion 17 may leak to the outside of the bag 10. It will come off easily. For this reason, it is possible to suppress the internal pressure of the accommodating portion 17 from becoming excessive, and thereby it is possible to suppress damage to the packaging material 30 during heating. Seal strength can be measured in accordance with JIS Z1707 7.5. As a measuring device, for example, a tensile tester RTC-1310A with a thermostatic chamber manufactured by Orientech Co., Ltd. can be used.

(Other variations of bags)
In the present embodiment described above, an example was shown in which the bag 10 is a gusset type bag, but the specific configuration of the bag 10 is not particularly limited. For example, the bag 10 may be a so-called four-sided seal bag formed by joining the inner surfaces of a front film 14 and a back film 15 made of the packaging material 30 at an upper part 11, a lower part 12, and a side part 13.

Second Embodiment Next, a second embodiment of the present invention will be described. Like the first embodiment described above, the second embodiment also relates to a packaging material and a packaged product including the packaging material. First, the problem to be solved by the second embodiment will be explained.

Conventionally, various packaging materials have been developed and proposed for filling and packaging various products such as food and beverages, pharmaceuticals, chemicals, cosmetics, and others. Such packaging materials are required to have various physical properties, which vary depending on the packaging purpose, contents to be filled, storage/distribution of the packaged product, etc. For example, one of their physical properties is gas barrier property that prevents the permeation of oxygen, water vapor, and the like.

Conventionally, various gas barrier materials that block the permeation of oxygen, water vapor, etc. have been developed and proposed. For example, aluminum foil, nylon film coated with polyvinylidene chloride resin, polyethylene terephthalate film, polyvinyl alcohol film, saponified ethylene-vinyl acetate copolymer film, polyacrylonitrile resin film, etc. Gas barrier materials have been developed and proposed.

Furthermore, in recent years, transparent barrier films consisting of a vapor-deposited layer of an inorganic oxide such as silicon oxide or aluminum oxide, or a vapor-deposited layer of a metal such as aluminum, have been developed on a plastic base material. Other barrier films have also been proposed. For example, Japanese Unexamined Patent Publication No. 2007-303000 proposes producing a barrier film by forming a vapor-deposited layer of an inorganic oxide on a nylon film.

Incidentally, packaging materials are required to have strength such as so-called puncture resistance, which is a characteristic that prevents the bag from tearing even when a sharp member with a pointed tip comes into contact with the packaging bag.

The present embodiment aims to provide a packaging material that can effectively solve these problems.

Next, the means to solve the problem will be described.

This embodiment includes a barrier laminate film and a sealant layer located inside the barrier laminate film, and the barrier laminate film includes a base material, a metal layer provided on the base material, and a sealant layer located inside the barrier laminate film. or a vapor deposited layer containing an inorganic compound, the base material contains polyester as a main component, and in at least one direction, the value obtained by dividing the tensile strength of the base material by the tensile elongation is 2.0 [MPa /%] or more, it is a packaging material.

In the packaging material according to this embodiment, the sealant layer may contain 90% by mass or more of polypropylene.

In the packaging material according to this embodiment, the sealant layer may contain linear low density polyethylene having a melting point of 100°C or higher.

In the packaging material according to the present embodiment, the sealant layer includes a first layer containing polypropylene and high-density polyethylene, and a second layer located closer to the barrier laminate film than the first layer and containing polypropylene or high-density polyethylene. It may have two layers.

In the packaging material according to the present embodiment, the base material of the barrier laminate film may have a puncture strength of 9.5N or more.

In the packaging material according to the present embodiment, the base material of the barrier laminated film may have a loop stiffness of 0.0017 N or more in the machine direction and the vertical direction, and may contain polyester as a main component.

In the packaging material according to the present embodiment, the base material of the barrier laminate film may contain polybutylene terephthalate as a main component.

In the packaging material according to the present embodiment, the barrier laminate film may further include a gas barrier coating film provided on the vapor deposition layer.

In the packaging material according to this embodiment, the vapor deposited layer of the barrier laminate film may be a transparent vapor deposited layer containing an inorganic compound.

In the packaging material according to the present embodiment, the vapor deposition layer of the barrier laminate film is a transparent vapor deposition layer containing aluminum oxide, the transparent vapor deposition layer includes a transition region, and the transition region is a layer of the barrier laminate film. The position of the peak of elemental bond Al ₂ O ₄ H detected by etching the film from the side of the transparent vapor deposited layer using time-of-flight secondary ion mass spectrometry (TOF-SIMS) and the transparent vapor deposited layer. and the interface with the base material, and the ratio of the thickness of the transition region to the thickness of the transparent vapor deposition layer may be 5% or more and 60% or less.

This embodiment is a packaging product made of the packaging material described above.

According to this embodiment, a packaging material having gas barrier properties and strength can be provided.

The second embodiment will be specifically described below. The packaging material 210 in the second embodiment is characterized by having a high stiffness polyester film provided with a vapor deposited layer. In the following description, the same names will be used for parts that can be configured in the same manner as in the first embodiment described above, and overlapping descriptions may be omitted. Further, if it is clear that the effects obtained in the first embodiment described above can also be obtained in the second embodiment, the explanation thereof may be omitted.

FIG. 16 is a cross-sectional view showing an example of packaging material 210 according to this embodiment. The packaging material 210 includes, in this order from the outside to the inside, a barrier laminate film 205, a printed layer 218, a first adhesive layer 213, and a sealant layer 212. The barrier laminate film 205 includes at least a base material 201 and a vapor deposited layer 202 in this order. The barrier multilayer film 205 may further include a gas barrier coating film 203 located on the vapor deposition layer 202. The base material 201 constitutes the outer surface 210y of the packaging material 210, and the sealant layer 212 constitutes the inner surface 210x of the packaging material 210.

In this embodiment, the outer surface is the outermost surface of the packaging material 210, and the inner surface is the innermost surface of the packaging material 210. Furthermore, in the present application, the term "order" in descriptions such as "provided in this order" and "layered in this order" indicates the order in the direction from the outside to the inside, unless otherwise specified.

FIG. 17 is a sectional view showing a modified example of the packaging material according to this embodiment. The example in FIG. 17 differs only in that the sealant layer 212 includes a first layer 2121 and a second layer 2122 located closer to the barrier laminated film 205 than the first layer 2121, and other configurations. is the same as the packaging material 210 shown in FIG. In the example shown in FIG. 17, the first layer 2121 of the sealant layer 212 constitutes the inner surface 210x of the packaging material 210. The thickness of the packaging material 210 is, for example, 60 μm or more, may be 70 μm or more, may be 80 μm or more, or may be 90 μm or more. Moreover, the thickness of the packaging material 210 may be 120 μm or less, 110 μm or less, or 100 μm or less.

The films and layers that make up the packaging material 210 will be described below. First, the barrier laminate film 205 will be explained.

[Base material]
The base material 201 used for the barrier laminated film 205 is a polyester film containing polyester as a main component. The base material 201 contains, for example, 51% by mass or more of polyester. The polyester includes at least one aromatic dicarboxylic acid selected from terephthalic acid, isophthalic acid, and 2,6-naphthalene dicarboxylic acid, and at least one aromatic dicarboxylic acid selected from ethylene glycol, 1,3-propanediol, and 1,4-butanediol. Polyesters mainly composed of aromatic polyesters containing one type of aliphatic alcohol are preferred. For example, polyesters include polyethylene terephthalate (hereinafter also referred to as PET), polybutylene terephthalate (hereinafter also referred to as PBT), and the like.

In order to prevent the bag from tearing when a sharp member with a pointed tip comes into contact with a packaging bag made of a packaging material including the barrier laminated film 205, the base of the barrier laminated film 205 must be It is preferable that the material 201 has resistance such as puncture resistance. Therefore, in this embodiment, it is proposed to use either a high stiffness PET film or a PBT film as the base material 201. Thereby, for example, the puncture strength of the base material 201 can be increased. For example, the puncture strength of the base material 201 can be 9.5N or more, more preferably 10N or more. Furthermore, the ratio of tensile strength to tensile elongation of the base material 201 can be increased. For example, in at least one direction, the value obtained by dividing the tensile strength of the base material by the tensile elongation is 2.0 [MPa/%] or more. As a result, the packaging material including the barrier laminated film 205 can have rigidity to prevent the bag from tearing even when a sharp member with a pointed tip comes into contact with it.

The high stiffness PET film and PBT film will be explained in detail below. First, the high stiffness PET film will be explained.

The high stiffness PET film is biaxially oriented PET having a loop stiffness of 0.0017N or more in at least one direction and containing 51% by mass or more of PET, as in the first embodiment described above. It's a film. The thickness of the high stiffness PET film is preferably 5 μm or more, more preferably 7 μm or more. Further, the thickness of the high stiffness PET film is preferably 25 μm or less, more preferably 20 μm or less. The method for measuring loop stiffness is the same as in the first embodiment described above.

Preferred mechanical properties of the high stiffness PET film will be further explained.
The puncture strength of the high stiffness PET film is preferably 9.5N or more, more preferably 10.0N or more.

The tensile strength and tensile elongation of the high stiffness PET film in the machine direction, the value obtained by dividing the tensile strength of the high stiffness PET film by the tensile elongation, the thermal shrinkage rate, and the tensile modulus of the high stiffness PET film in the machine direction are the same as those of the first embodiment described above. Since this is the same as in the case of the stiffness polyester film, the explanation will be omitted.

In the manufacturing process of high stiffness PET film, as in the case of high stiffness polyester film, for example, first, a PET film obtained by melting and molding polyethylene terephthalate is heated at 90°C in both the machine direction and the vertical direction. A first stretching step of stretching 3 to 4.5 times at ~145°C is performed. Subsequently, a second stretching step is performed in which the plastic film is stretched 1.1 to 3.0 times in the machine direction and in the vertical direction at 100° C. to 145° C., respectively. Thereafter, heat fixation is performed at a temperature of 190°C to 220°C. Subsequently, a relaxation treatment (treatment for reducing the film width) of about 0.2% to 2.5% is performed at a temperature of 100° C. to 190° C. in the flow direction and the vertical direction. In these steps, by adjusting the stretching ratio, stretching temperature, heat setting temperature, and relaxation treatment rate, a high stiffness PET film having the above-mentioned mechanical properties can be obtained.

The PET constituting the high stiffness PET film may include biomass-derived PET, as in the first embodiment described above. In this case, the high stiffness PET film may be composed only of biomass-derived PET. Alternatively, the high stiffness PET film may be composed of biomass-derived PET and fossil fuel-derived PET. The biomass-derived PET contained in the high stiffness PET film, the degree of biomass of the high stiffness PET film, etc. are the same as in the case of the high stiffness polyester film of the first embodiment described above, so a description thereof will be omitted.

Next, the PBT film will be explained. A PBT film is a stretched plastic film containing 51% by mass or more of PBT. The advantages of the base material 201 containing PBT will be explained below.

PBT has excellent heat resistance. Therefore, it is possible to suppress deformation of the base material 201 or decrease in strength of the base material 201 when subjecting a packaging bag containing contents such as food to boiling treatment or retort treatment. Retort processing is a process in which the contents are filled into a packaging bag, the packaging bag is sealed, and then the packaging bag is heated under pressure using steam or heated hot water. The temperature of the retort treatment is, for example, 120° C. or higher. Boiling is a process in which the contents are filled into a packaging container, the packaging container is sealed, and then the packaging container is boiled in hot water under atmospheric pressure. The temperature of the boiling treatment is, for example, 90°C or higher and 100°C or lower.

PBT also has high strength. Therefore, the packaging bag can be provided with puncture resistance, as in the case where the packaging material 210 constituting the packaging bag contains nylon. The puncture strength of the PBT film is preferably 9.5N or more, more preferably 10.0N or more.

The tensile strength of the PBT film in the machine direction is preferably 150 MPa or more, more preferably 180 MPa or more. The tensile strength of the PBT film in the vertical direction is preferably 250 MPa or more, more preferably 280 MPa or more.
The tensile elongation of the PBT film in the machine direction is preferably 220% or less, more preferably 200% or less. The tensile elongation of the PBT film in the vertical direction is preferably 120% or less, more preferably 110% or less.
Preferably, in at least one direction, the value obtained by dividing the tensile strength of the PBT film by the tensile elongation is 2.0 [MPa/%] or more. For example, the value obtained by dividing the tensile strength of the PBT film in the vertical direction (TD) by the tensile elongation is preferably 2.0 [MPa/%] or more, more preferably 2.2 [MPa/%] or more. It is more preferably 2.5 [MPa/%] or more.

Furthermore, PBT has the property of being less likely to absorb moisture than nylon. Therefore, even when the base material 201 containing PBT is placed on the outer surface of the packaging material 210, it is possible to prevent the base material 201 from absorbing moisture and reducing the lamination strength of the packaging material 210. can.

The structure of the base material 201 containing PBT will be described in detail below. In this embodiment, as the configuration of the base material 201 containing PBT, either the following first configuration or second configuration may be adopted.

[First configuration of base material containing PBT]
The content of PBT in the base material 201 according to the first configuration is preferably 51% by mass or more, more preferably 60% by mass or more, further preferably 70% by mass or more, particularly preferably 75% by mass or more, and most preferably It is 80% by mass or more. By setting the PBT content to 51% by mass or more, the base material 201 can have excellent impact strength and pinhole resistance.

The dicarboxylic acid component of PBT used as a main component is preferably 90 mol% or more of terephthalic acid, more preferably 95 mol% or more, still more preferably 98 mol% or more, and most preferably 100 mol% or more. It is mole%. The glycol component preferably contains 1,4-butanediol in an amount of 90 mol% or more, more preferably 95 mol% or more, even more preferably 97 mol% or more, and most preferably 1,4-butanediol during polymerization. No by-products other than those produced by the ether bond of butanediol are included.

The base material 201 may contain polyester resin other than PBT. Thereby, for example, film formability and mechanical properties of the base material 201 can be adjusted when the film-like base material 201 is biaxially stretched.
Examples of polyester resins other than PBT include polyester resins such as PET, polyethylene naphthalate (PEN), polybutylene naphthalate (PBN), and polypropylene terephthalate (PPT), as well as isophthalic acid, orthophthalic acid, naphthalene dicarboxylic acid, and biphenyl dicarboxylic acid. , PBT resin copolymerized with dicarboxylic acids such as cyclohexanedicarboxylic acid, adipic acid, azelaic acid, and sebacic acid, ethylene glycol, 1,3-propylene glycol, 1,2-propylene glycol, neopentyl glycol, 1,5 Examples include PBT resins in which diol components such as -pentanediol, 1,6-hexanediol, diethylene glycol, cyclohexanediol, polyethylene glycol, polytetramethylene glycol, and polycarbonate diol are copolymerized.

The amount of polyester resin other than PBT added is preferably 49% by mass or less, more preferably 40% by mass or less. If the amount of polyester resin other than PBT exceeds 49% by mass, the mechanical properties of PBT may be impaired, and impact strength, pinhole resistance, and drawing formability may become insufficient.

The base material 201 may contain, as an additive, a polyester-based or polyamide-based elastomer copolymerized with at least one of a flexible polyether component, polycarbonate component, and polyester component. Thereby, pinhole resistance during bending can be improved. The amount of additive added is, for example, 20% by mass. If the amount of the additive exceeds 20% by mass, the effect of the additive may become saturated or the transparency of the base material 201 may decrease.

An example of a method for producing the film-like base material 201 according to the first configuration will be described. Here, a method for producing the film-like base material 201 by a casting method will be described. More specifically, a method will be described in which resins having the same composition are formed into multiple layers during casting.

Since PBT has a fast crystallization speed, crystallization progresses even during casting. At this time, if a single layer is cast without multilayering, the crystals will grow to a large size because there is no barrier that can suppress crystal growth, and the resulting unstretched original fabric will be yield stress increases. For this reason, when biaxially stretching the unstretched original fabric, it becomes easy to break. Further, it is conceivable that the yield stress of the obtained biaxially stretched film becomes high and the formability of the biaxially stretched film becomes insufficient.
On the other hand, if the same resin is multilayered during casting, the stretching stress of the unstretched sheet can be reduced. Therefore, stable biaxial stretching becomes possible, and the yield stress of the obtained biaxially stretched film becomes low. This makes it possible to obtain a film that is flexible and has high breaking strength.

FIG. 18 is a cross-sectional view showing an example of the layer structure of the base material 201. When the base material 201 is produced by multilayering and casting a resin, the base material 201 has a multilayer structure including a plurality of layers 201a, as shown in FIG. 18. Each of the plurality of layers 201a contains PBT as a main component. For example, each of the plurality of layers 201a preferably contains 51% by mass or more of PBT, more preferably 60% by mass or more of PBT. Note that in the plurality of layers 201a, the (n+1)th layer 201a is directly stacked on the nth layer 201a. That is, no adhesive layer or bonding layer is interposed between the plurality of layers 201a.

The reason why the properties of the PBT film are improved by multilayering is presumed as follows. When resins are laminated, even if the compositions of the resins are the same, interfaces between the layers exist, and crystallization is accelerated by the interfaces. On the other hand, the growth of large crystals beyond the layer thickness is suppressed. Therefore, it is thought that the size of the crystals (spherulites) becomes smaller.

As a specific method for reducing the size of spherulites by multilayering, a general multilayering device (multilayer feed block, static mixer, multilayer multimanifold, etc.) can be used. For example, a method can be used in which thermoplastic resins sent out from different channels using two or more extruders are laminated into multiple layers using a feed block, static mixer, multi-manifold die, or the like. In addition, when multilayering resins of the same composition, it is also possible to use only one extruder and introduce the above-mentioned multilayering device into the melt line from the extruder to the die.

The base material 201 has a multilayer structure including at least 10 layers 201a, preferably 60 layers or more, more preferably 250 layers or more, still more preferably 1000 layers or more. By increasing the number of layers, the size of spherulites in the unstretched original PBT can be reduced, and subsequent biaxial stretching can be stably performed. Furthermore, the yield stress of PBT in the form of a biaxially stretched film can be reduced. Preferably, the diameter of spherulites in the unstretched original PBT is 500 nm or less.

When biaxially stretching an unstretched PBT film to produce a biaxially stretched film, the stretching temperature (hereinafter also referred to as MD stretching temperature) in the longitudinal stretching direction (hereinafter referred to as MD) is preferably 40°C or higher. The temperature is more preferably 45°C or higher. By setting the MD stretching temperature to 40° C. or higher, it is possible to suppress the film from breaking. Further, the MD stretching temperature is preferably 100°C or lower, more preferably 95°C or lower. By setting the MD stretching temperature to 100° C. or lower, it is possible to suppress the phenomenon that orientation of the biaxially stretched film does not occur.

The stretching ratio in MD (hereinafter also referred to as MD stretching ratio) is preferably 2.5 times or more. This makes it possible to orient the biaxially stretched film and achieve good mechanical properties and a uniform thickness. The MD stretching ratio is, for example, 5 times or less.

The stretching temperature (hereinafter also referred to as TD stretching temperature) in the transverse stretching direction (hereinafter also referred to as TD) is preferably 40° C. or higher. By setting the TD stretching temperature to 40° C. or higher, it is possible to prevent the film from breaking. Further, the TD stretching temperature is preferably 100°C or less. By setting the TD stretching temperature to 100° C. or lower, it is possible to suppress the phenomenon that orientation of the biaxially stretched film does not occur.

The stretching ratio in TD (hereinafter also referred to as TD stretching ratio) is preferably 2.5 times or more. This makes it possible to orient the biaxially stretched film and achieve good mechanical properties and a uniform thickness. The MD stretching ratio is, for example, 5 times or less.

The TD relaxation rate is preferably 0.5% or more. Thereby, it is possible to suppress the occurrence of breakage during heat setting of the biaxially stretched PBT film. Further, the TD relaxation rate is preferably 10% or less. Thereby, it is possible to suppress the occurrence of thickness unevenness due to sagging in the biaxially stretched PBT film.

The thickness of the layer 201a of the base material 201 shown in FIG. 18 is preferably 3 nm or more, more preferably 10 nm or more. Further, the thickness of the layer 201a is preferably 200 nm or less, more preferably 100 nm or less.
Further, the thickness of the base material 201 is preferably 9 μm or more, more preferably 12 μm or more. Further, the thickness of the base material 201 is preferably 25 μm or less, more preferably 20 μm or less. By setting the thickness of the base material 201 to 9 μm or more, the base material 201 has sufficient strength. Further, by setting the thickness of the base material 201 to 25 μm or less, the base material 201 exhibits excellent moldability. Therefore, the process of manufacturing a packaging bag by processing the packaging material 210 including the base material 201 can be efficiently carried out.

[Second configuration of base material containing PBT]
The base material 201 according to the second configuration is made of a single layer film containing polyester whose main repeating unit is butylene terephthalate. For example, the base material 201 is mainly composed of 1,4-butanediol or its ester-forming derivative as a glycol component and terephthalic acid or its ester-forming derivative as a dibasic acid component, and is made by condensing them. Contains homo- or copolymer-type polyesters obtained by The content of PBT in the base material 201 according to the second configuration is preferably 51% by mass or more, more preferably 60% by mass or more, further preferably 70% by mass or more, further preferably 80% by mass or more, and most preferably is 90% by mass or more. Moreover, it is preferable that the base material 201 according to the second configuration is composed of only polybutylene terephthalate and additives.

In order to impart mechanical strength to the base material 201, PBT with a melting point of 200° C. or more and 250° C. or less and an IV value (intrinsic viscosity) of 1.10 dl/g or more and 1.35 dl/g or less is used. is preferred. Furthermore, those having a melting point of 215° C. or more and 225° C. or less and an IV value of 1.15 dl/g or more and 1.30 dl/g or less are particularly preferable. These IV values may be satisfied by the entire material constituting the base material 201. The IV value can be calculated based on JIS K 7367-5:2000.

The base material 201 according to the second configuration may contain a polyester resin other than PBT, such as PET, in a range of 30% by mass or less. When the base material 201 contains PET in addition to PBT, PBT crystallization can be suppressed and the stretchability of the PBT film can be improved. As the PET to be mixed with the PBT of the base material 201, polyester having ethylene terephthalate as a main repeating unit can be used. For example, a homotype mainly composed of ethylene glycol as a glycol component and terephthalic acid as a dibasic acid component can be preferably used. In order to impart good mechanical strength properties, it is preferable to use PET with a melting point of 240° C. or more and 265° C. or less, and an IV value of 0.55 dl/g or more and 0.90 dl/g or less. Furthermore, those having a melting point of 245° C. or more and 260° C. or less and an IV value of 0.60 dl/g or more and 0.80 dl/g or less are particularly preferred.
By controlling the blending amount of PET to 30% by mass or less, it is possible to prevent the rigidity of the unstretched original fabric and the stretched film from becoming too high. This can prevent the stretched film from becoming brittle and reducing its pressure strength, impact strength, puncture strength, etc. Moreover, it is possible to suppress the occurrence of stretching failures when stretching an unstretched original fabric.

The base material 201 contains a lubricant, an anti-blocking agent, an inorganic filler, an antioxidant, an ultraviolet absorber, an antistatic agent, a flame retardant, a plasticizer, a coloring agent, a crystallization inhibitor, and a crystallization promoter, as necessary. It may also contain additives such as. In addition, the polyester resin pellets used as a raw material for the base material 201 have a moisture content of 0.05% by weight or less, preferably 0.01% by weight or less before heating and melting, in order to avoid a decrease in viscosity due to hydrolysis during heating and melting. It is preferable to pre-dry the material thoroughly before use.

An example of a method for producing the film-like base material 201 according to the second configuration will be described.

In order to stably produce the film of the base material 201 having the above-described structure, it is important to suppress the growth of crystals in the unstretched original film state. Specifically, when an extruded PBT-based melt is cooled to form a film, the crystallization temperature range of the polymer is cooled at a certain rate or higher, that is, the cooling rate of the original fabric becomes an important factor. The cooling rate of the original fabric is, for example, 200° C./second or more, preferably 250° C./second or more, particularly preferably 350° C./second or more. Since the unstretched original fabric formed at a high cooling rate maintains a low crystalline state, the stability of bubbles during stretching is improved. Furthermore, since high-speed film formation becomes possible, film productivity also improves. When the cooling rate is less than 200° C./sec, it is thought that the crystallinity of the obtained unstretched original fabric becomes high and the drawability decreases. Furthermore, in extreme cases, the stretching bubble may burst and the stretching may not continue.

The unstretched original fabric containing PBT as a main component is preferably transported to a space where biaxial stretching is performed while maintaining the ambient temperature at 25° C. or lower, preferably at 20° C. or lower. Thereby, even if the residence time becomes long, the crystallinity of the unstretched original fabric immediately after film formation can be maintained.

The biaxial stretching method for obtaining a stretched film by stretching an unstretched original film is not particularly limited. For example, by tubular method or tenter method, the longitudinal direction and the transverse direction may be stretched simultaneously, or the longitudinal direction and the transverse direction may be stretched sequentially. Among these, the tubular method is particularly preferably employed because it can produce a stretched film with good balance of physical properties in the circumferential direction.

In the tubular method, an unstretched original fabric introduced into a stretching space is passed between a pair of low-speed nip rolls, and then heated with a stretching heater while forcing air into the roll. After the stretching is completed, air is blown onto the stretched film by a cooling shoulder air ring. In consideration of stretching stability, strength properties, transparency, and thickness uniformity of the stretched film, the stretching ratio is preferably 2.7 times or more and 4.5 times or less in MD and TD, respectively. By setting the stretching ratio to 2.7 times or more, sufficient tensile modulus and impact strength of the stretched film can be ensured. In addition, by setting the stretching ratio to 4.5 times or less, it is possible to suppress the occurrence of excessive strain on the molecular chains due to stretching, and to suppress the occurrence of breaks and punctures during the stretching process, thereby stabilizing the stretched film. It can be made into

The stretching temperature is preferably 40°C or higher and 80°C or lower, particularly preferably 45°C or higher and 65°C or lower. Since the unstretched original fabric produced at the above-mentioned high cooling rate has low crystallinity, the unstretched original fabric can be stably stretched even if the stretching temperature is relatively low. Further, by setting the stretching temperature to 80° C. or lower, shaking of the stretching bubbles can be suppressed and a stretched film with good thickness accuracy can be obtained. Further, by setting the stretching temperature to 40° C. or higher, it is possible to suppress occurrence of excessive stretching orientation crystallization due to low-temperature stretching and prevent whitening of the film.

The base material 201 produced as described above is composed of, for example, a single layer containing polyester whose main repeating unit is butylene terephthalate. According to the above-mentioned production method, since the unstretched original fabric is formed into a film at a high cooling rate, even when the unstretched original fabric is composed of a single layer, a low crystalline state can be maintained. Therefore, the unstretched original fabric can be stretched stably.

When the base material 201 contains PBT, the heat resistance of the barrier laminate film 205 and the heat resistance of the packaging material 210 including the barrier laminate film 205 can be increased. For example, the tensile modulus of the barrier laminated film 205 and the packaging material 210 can be made sufficiently high. In particular, the tensile modulus (hereinafter also referred to as hot tensile modulus) of the barrier laminate film 205 and the packaging material 210 in a high temperature atmosphere, for example, a 100° C. atmosphere can be made sufficiently high.

Also in this embodiment, by including the high stiffness PET film or PBT film in the packaging material 210, the puncture strength of the packaging material 210 can be increased as in the case of the first embodiment described above. The puncture strength of the packaging material 210 is, for example, 12N or more, and may be 13N or more. Further, as in the case of the first embodiment described above, the stiffness of the packaging material 210 can be increased. For example, the loop stiffness of the packaging material 210 per unit thickness of the packaging material 30 can be increased. The value obtained by dividing the loop stiffness of the packaging material 30 in at least one direction by the thickness of the packaging material 210 is, for example, 0.00085 N/μm or more, and may be 0.00090 N/μm or more, and is 0.00095 N/μm. It may be more than 0.00100 N/μm. For example, the value obtained by dividing the loop stiffness of the packaging material 210 in the machine direction (MD) by the thickness of the packaging material 210 is, for example, 0.00085 N/μm or more, and may be 0.00090 N/μm or more, and 0.00085 N/μm or more. It may be 00095 N/μm or more, or it may be 0.00100 N/μm or more. Further, the value obtained by dividing the loop stiffness of the packaging material 210 in the vertical direction (TD) by the thickness of the packaging material 30 is, for example, 0.00080 N/μm or more, and may be 0.00085 N/μm or more, and 0.00080 N/μm or more. It may be 00090 N/μm or more, or 0.00095 N/μm or more.

[Vapour-deposited layer]
Next, the vapor deposited layer 202 of the barrier laminate film 205 will be explained.

The vapor deposition layer 202 is a thin film that has gas barrier properties that prevent or block the permeation of oxygen gas, water vapor, and the like. The vapor deposition layer 202 may be a metal layer containing a light-blocking metal such as aluminum, or may be a transparent vapor deposition layer formed of a transparent inorganic compound. For example, the vapor deposition layer 202 is a transparent vapor deposition layer formed of a transparent inorganic oxide.

Hereinafter, a case where the vapor deposition layer 202 is a transparent vapor deposition layer will be described. The inorganic oxide forming the vapor deposition layer 202 contains, for example, as a main component an aluminum compound containing at least aluminum oxide or aluminum nitride, carbide, or hydroxide alone or in a mixture thereof. For example, the inorganic oxide contains aluminum oxide as a main component.
Further, the vapor deposition layer 202 may be a layer containing a silicon compound as a main component. For example, the inorganic oxide layer contains silicon oxide (silicon oxide) as a main component.
Furthermore, the vapor deposition layer 202 contains an aluminum compound such as the above-mentioned aluminum oxide as a main component, and further contains silicon oxide, silicon nitride, silicon oxynitride, silicon carbide, magnesium oxide, titanium oxide, tin oxide, and indium oxide. , metal oxides such as zinc oxide and zirconium oxide, or metal nitrides, carbides, and mixtures thereof.

The thickness of the vapor deposition layer 202 is preferably 3 nm or more and 50 nm or less, more preferably 9 nm or more and 30 nm or less.

(Gas barrier coating film)
When the vapor deposition layer 202 is a transparent vapor deposition layer, the gas barrier coating film 203 of the barrier multilayer film 205 mechanically and chemically protects the vapor deposition layer 202 and improves the barrier properties of the barrier multilayer film 205. It is layered so as to be in contact with the vapor deposition layer 202. The gas barrier coating film 203 is a cured film formed by a coating agent for a gas barrier coating film made of a resin composition containing a metal alkoxide, a water-soluble resin containing a hydroxyl group, and a silane coupling agent added as necessary. be.

The mass ratio of hydroxyl group-containing water-soluble resin/metal alkoxide in the resin composition is preferably 5/95 or more and 20/80 or less, and more preferably 8/92 or more and 15/85 or less. When it is smaller than the above range, the barrier effect of the barrier coating layer tends to be insufficient, and when it is larger than the above range, the rigidity and brittleness of the barrier coating layer tend to increase.

The thickness of the gas barrier coating film 203 is preferably 100 nm or more and 800 nm or less. When it is thinner than the above range, the barrier effect of the gas barrier coating film 203 tends to be insufficient, and when it is thicker than the above range, rigidity and brittleness tend to increase.

The metal alkoxide has the general formula R ₁ nM(OR ₂ )m (wherein R ₁ and R ₂ represent a hydrogen atom or an organic group having 1 to 8 carbon atoms, M represents a metal atom, and n represents an integer of 0 or more, m represents an integer of 1 or more, and n+m represents the valence of M. Even if each of the plurality of R ₁ and R ₂ in one molecule is the same, may be different.)...Represented by (XI).

Specific examples of the metal atom represented by M in the metal alkoxide include silicon, zirconium, titanium, aluminum, tin, lead, borane, and others. For example, alkoxy in which M is Si (silicon) Preference is given to using silanes.

In the above general formula (XI), specific examples of OR ₂ include a hydroxyl group, a methoxy group, an ethoxy group, an n-propoxy group, an n-butoxy group, an i-propoxy group, a butoxy group, and a 3-methacryloxy group. Examples include alkoxy groups such as 3-acryloxy groups and phenoxy groups, and phenoxy groups.

In the above, specific examples of R ₁ include methyl group, ethyl group, n-propyl group, isopropyl group, phenyl group, p-styryl group, 3-chloropropyl group, trifluoromethyl group, vinyl group, γ-glycyl group, Examples include sidoxypropyl group, methacryl group, and γ-aminopropyl group.

Specific examples of alkoxysilane include tetramethoxysilane, tetraethoxysilane, tetrapropoxysilane, tetraisopropoxysilane, tetrabutoxysilane, tetraphenoxysilane, methyltrimethoxysilane, methyltriethoxysilane, methyltripropoxysilane, Methyltributoxysilane, methyltriphenoxysilane, phenylphenoxysilane, ethyltrimethoxysilane, ethyltriethoxysilane, dimethyldimethoxysilane, dimethyldiethoxysilane, n-propyltrimethoxysilane, n-propyltriethoxysilane, isopropyltrimethoxy Silane, isopropyltriethoxysilane, dimethyldiethoxysilane, diphenyldimethoxysilane, diphenyldiethoxysilane, vinyltrimethoxysilane, vinyltriethoxysilane, phenyltrimethoxysilane, phenyltriethoxysilane, p-styryltrimethoxysilane, 3- Methacryloxypropylmethyldimethoxysilane, 3-methacryloxypropylmethyldiethoxysilane, 3-methacryloxypropyltrimethoxysilane, 3-methacryloxypropyltriethoxysilane, 3-acryloxypropyltrimethoxysilane, 3-acryloxypropyltrimethoxysilane Examples include various alkoxysilanes such as ethoxysilane, 3-chloropropyltriethoxysilane, trifluoromethyltrimethoxysilane, and 1,6-bis(trimethoxysilyl)hexane, and phenoxysilane. In this embodiment, condensation products of these alkoxysilanes can also be used, and specifically, for example, polytetramethoxysilane, polytetraethoxysilane, etc. can be used.

The silane coupling agent is used to adjust the crosslinking density of the cured film made of the metal alkoxide and the hydroxyl group-containing water-soluble resin to form a film with barrier properties and hot water treatment resistance.

The silane coupling agent has the general formula: R ₃ nSi(OR ₄ )4-n...(XII)
(However, in the formula, R ₃ and R ₄ each independently represent an organic functional group, and n is 1 to 3.)
It is expressed as

In the above general formula (XII), R ₃ is, for example, a hydrocarbon group such as an alkyl group or an alkylene group, an epoxy group, a (meth)acryloxy group, a ureido group, a vinyl group, an amino group, an isocyanurate group, or an isocyanate group. Examples include functional groups having the following. Specifically, at least one of two or three R ₃ 's is preferably a functional group having an epoxy group, such as a 3-glycidoxypropyl group and a 2-(3,4 epoxycyclohexyl) group. It is more preferable that Note that R ₃ may be the same or different.

In the above general formula (XII), R ₄ is, for example, an organic functional group having 1 to 8 carbon atoms, preferably an alkyl group having 1 to 8 carbon atoms, which may have a branch, or an alkyl group having 3 to 8 carbon atoms. 7 is an alkoxyalkyl group. For example, examples of the alkyl group having 1 to 8 carbon atoms include methyl group, ethyl group, n-propyl group, i-propyl group, n-butyl group, sec-butyl group, and the like. Examples of alkoxyalkyl groups having 3 to 7 carbon atoms include methyl ethyl ether, diethyl ether, methyl propyl ether, methyl isopropyl ether, ethyl propyl ether, ethyl isopropyl ether, methyl butyl ether, ethyl butyl ether, methyl sec-butyl ether, ethyl sec -butyl ether, methyl tert-butyl ether, ethyl tert-butyl ether, and other linear or branched ethers with one hydrogen atom removed. Note that (OR ₄ ) may be the same or different.

Examples of the silane coupling agent represented by the above general formula (XII) include 3-glycidoxypropyltrimethoxysilane and 3-glycidoxypropyltriethoxysilane when n=1. When n=2, examples include 3-glycidoxypropylmethyldimethoxysilane and 3-glycidoxypropylmethyldiethoxysilane, and when n=3, examples include 3-glycidoxypropyldimethylmethoxysilane, 3-glycidoxypropyldimethylmethoxysilane, etc. Examples include sidoxypropyldimethylethoxysilane, 2-(3,4-epoxycyclohexyl)dimethylmethoxysilane, and 2-(3,4-epoxycyclohexyl)dimethylethoxysilane.

In particular, the crosslinking density of the cured film of the barrier coating layer using 3-glycidoxypropylmethyldimethoxysilane and 3-glycidoxypropylmethyldiethoxysilane is lower than that of the system using trialkoxysilane. Become. Therefore, while it is a film with excellent gas barrier properties and hot water treatment resistance, it becomes a flexible cured film and has excellent bending resistance, so packaging materials using this barrier film have gas barrier properties even after the Gelboflex test. Hard to deteriorate.

The silane coupling agent can be used as a mixture of n=1, 2, or 3, and the ratio and amount of the silane coupling agent used are determined by the design of the cured film of the barrier coating layer. .

The hydroxyl group-containing water-soluble resin can undergo dehydration co-condensation with a metal alkoxide, and the degree of saponification is preferably 90% or more and 100% or less, more preferably 95% or more and 100% or less, and 99% or more and 100% or less. % or less is more preferable. If the degree of saponification is smaller than the above range. The hardness of the barrier coating layer tends to decrease.

Specific examples of hydroxyl group-containing water-soluble resins include polyvinyl alcohol resins, ethylene-vinyl alcohol copolymers, polymers of bifunctional phenol compounds and bifunctional epoxy compounds, etc. They may be used, or two or more types may be used in combination, or they may be copolymerized. Among these, polyvinyl alcohol is particularly preferred because of its excellent flexibility and affinity, and polyvinyl alcohol-based resins are preferred.

Specifically, for example, polyvinyl alcohol resin obtained by saponifying polyvinyl acetate or ethylene/vinyl alcohol copolymer obtained by saponifying a copolymer of ethylene and vinyl acetate is used. can do.
Examples of such polyvinyl alcohol-based resins include PVA-124 (saponification degree = 99%, polymerization degree = 2,400) manufactured by Kuraray Co., Ltd., and Gohsenol NM-14 (saponification degree = 2,400) manufactured by Nippon Gosei Chemical Industry Co., Ltd. = 99%, degree of polymerization = 1,400).

(Preferred configuration of barrier laminate film)
Next, a preferred structure of the barrier laminated film 205 in the thickness direction when the vapor deposition layer 202 is a transparent vapor deposition layer containing aluminum oxide will be described with reference to FIG. 19. FIG. 19 shows time-of-flight secondary ion mass spectrometry (TOF- FIG. 4 is a diagram showing the results of measuring ions originating from a vapor deposited layer 202 containing aluminum oxide and ions originating from a base material 201 using SIMS. The vapor deposited layer 202 of the barrier laminate film 205 includes a transition region specified by the graphical analysis diagram shown in FIG.

The transition region is the position of the peak of the elemental bond Al ₂ O ₄ H that transforms into aluminum hydroxide, which is detected by etching the barrier multilayer film 205 from the gas barrier coating film 203 side using TOF-SIMS. This is the region between T ₂ and the interface T ₁ between the vapor deposition layer 202 and the base material 201. The interface T ₁ between the vapor deposited layer 202 and the base material 201 is specified as a position where the intensity of the graph of the element C ₆ is half of the intensity of the element C ₆ in the base material 201 . In FIG. 19, the symbol W ₁ represents the thickness of the transition region.

The ratio of the thickness W ₁ of the transition region to the thickness of the vapor deposited layer 202 (hereinafter also referred to as the metamorphism rate of the transition region) is preferably 5% or more and 60% or less. By setting the denaturation rate to 5% or more and 60% or less, the barrier properties of the barrier laminate film 205 against water vapor can be improved when the packaging material containing the barrier laminate film 205 is subjected to sterilization treatment such as boiling or retort treatment. It is possible to suppress the decrease. The retort process is a process in which a packaging bag made of a packaging material including the barrier laminated film 205 is filled with contents, the packaging bag is sealed, and then the packaging bag is heated under pressure. The temperature of the retort treatment is, for example, 120° C. or higher. The boiling process is a process in which the contents are filled into a packaging bag, the packaging bag is sealed, and then the packaging bag is boiled in hot water under atmospheric pressure. The temperature of the boiling treatment is, for example, 90°C or higher and 100°C or lower. In addition, the packaging material containing the barrier laminated film 205 with a transition region denaturation rate of 5% or more and 60% or less is used in packaging bags that are not subjected to sterilization treatment such as boiling or retort treatment. It can also function effectively in maintaining barrier properties against gases such as oxygen and water vapor.

The interface between the base material 201 and the deposited layer 202 is subjected to mechanical and chemical stress due to heat. Therefore, in order to suppress deterioration of adhesion and barrier properties, it is important to firmly cover the base material 201 with the deposited layer 202 at the interface between the base material 201 and the deposited layer 202.

Aluminum hydroxide has good adhesion to plastic films such as polyester films due to its chemical structure, and because it forms a dense network itself, it has high water vapor barrier properties. However, the bonding structure based on hydrogen bonds between aluminum hydroxide and plastic film easily collapses microscopically due to heat stress. Furthermore, the aluminum hydroxide network easily penetrates into the membrane due to the affinity between water molecules and the grain boundaries of aluminum hydroxide.

In this embodiment, in order to minimize the transition region formed by aluminum hydroxide in the vapor deposition layer 202 containing aluminum oxide at the interface with the base material 201, attention is paid to the elemental bond Al ₂ O ₄ H, and its presence is Control quantity. As a result, aluminum hydroxide generated from elemental bonds Al ₂ O ₄ H due to heat stress is suppressed, and by increasing the ratio of the aluminum oxide layer with relatively little aluminum hydroxide, microscopic damage caused by water molecules caused by heat stress is suppressed. This is intended to suppress destruction of the vapor deposited layer 202 and destruction of the interface with the plastic film. Thereby, a barrier laminate film 205 having unprecedented adhesiveness and barrier properties can be provided.

The vapor deposition layer 202 containing aluminum oxide can be formed by forming the vapor deposition layer 202 on the surface of the base material 201 that has been pretreated with oxygen plasma. As the vapor deposition method for forming the vapor deposition layer 202, various vapor deposition methods can be applied from among physical vapor deposition and chemical vapor deposition. Physical vapor deposition methods can be selected from the group consisting of vapor deposition, sputtering, ion plating, ion beam assist, and cluster ion beam methods, and chemical vapor deposition methods include plasma CVD, plasma polymerization, and thermal It can be selected from the group consisting of CVD method and catalytic reaction type CVD method. In this embodiment, a physical vapor deposition method is suitable.

A specific example of a method for obtaining the graph of FIG. 19 will be described. First, using Cs, etching is performed from the outermost surface of the gas barrier coating film 203 to remove the elemental bonds at the interface between the gas barrier coating film 203, the vapor deposition layer 202, the base material 201, etc., and the elemental bonds in the vapor deposition layer 202. Conduct analysis. As a result, the graph shown in FIG. 19 can be obtained.

Next, a specific example of a method for analyzing the graph of FIG. 19 will be described. Here, a case will be described in which the gas barrier coating film 203 contains silicon oxide.

First, in the graph, the position where the strength of SiO ₂ (mass number 59.96), which is a constituent element of the gas barrier coating film 203, is half of the strength in the gas barrier coating film 203 is located between the gas barrier coating film 203 and the vapor deposited layer. 202 interface. Next, a position where the strength of C ₆ (mass number 72.00), which is a constituent material of the base material 201, is half of the strength in the base material 201 is specified as the interface between the base material 201 and the vapor deposited layer 202. Furthermore, the distance between the two interfaces in the thickness direction is employed as the thickness of the vapor deposited layer 202.

Next, the peak of the measured elemental bond Al ₂ O ₄ H (mass number 118.93) is determined, and the region from the peak to the interface is defined as a transition region. However, if the gas barrier coating film 203 is composed of a material having the same mass number as Al ₂ O ₄ H (mass number 118.93), it is necessary to separate the waveform of 118.93.

When the reactant AlSiO ₄ and the hydroxide Al ₂ O ₄ H are generated at the interface between the gas barrier coating film 203 and the vapor deposited layer 202, they and the Al present at the interface between the base material 201 and the vapor deposited layer 202. ₂ O ₄ H can be separated. In this way, waveform separation can be handled appropriately depending on the material of the gas barrier coating film 203.

In waveform separation, for example, a profile with a mass number of 118.93 obtained by TOF-SIMS is subjected to nonlinear curve fitting using a Gaussian function, and overlapping peaks are separated using a least squares method Levenberg Marquardt algorithm. It can be carried out.

Note that the above analysis assumes that the barrier multilayer film 205 includes the base material 201, the vapor deposited layer 202, and the gas barrier coating film 203, but a similar analysis assumes that the barrier multilayer film 205 includes the base material 201. It is also applicable to a case in which the vapor deposition layer 202 is included but the gas barrier coating film 203 is not included. Even if the barrier laminated film 205 does not include the gas barrier coating film 203, the packaging material containing the barrier laminated film 205 can be boiled by adjusting the transformation rate of the transition region of the vapor deposited layer 202 within a predetermined range. When sterilization treatment such as treatment or retort treatment is performed, the barrier properties of the barrier laminated film 205 against water vapor can be prevented from deteriorating. When the barrier multilayer film 205 includes a base material 201 and a vapor deposited layer 202 and etching is performed from the vapor deposited layer 202 side using time-of-flight secondary ion mass spectrometry (TOF-SIMS), the transition region of the vapor deposited layer 202 is It is preferable that the metamorphosis rate is 45% or less.

Next, the mechanical properties of the barrier laminate film 205 will be explained. The mechanical properties of the barrier laminate film 205 are mainly determined by the mechanical properties of the base material 201. Therefore, mechanical properties such as loop stiffness, puncture strength, tensile strength, tensile elongation, value obtained by dividing tensile strength by tensile elongation, thermal shrinkage rate, and tensile modulus of the barrier laminated film 205 are different from those of the base material 201. The mechanical properties are equivalent to the high stiffness PET film and PBT film that constitute it. Therefore, if the measurement results of the mechanical properties of the barrier laminated film 205 are within the above-mentioned preferred range, the measurement results of the mechanical properties of the base material 201 made of high stiffness PET film or PBT film will also be as described above. is considered to be within the preferable range.

[Sealant layer]
Next, the sealant layer 212 will be explained. The sealant layer 212 is a layer containing thermoplastic resin that constitutes the inner surface 210x of the packaging material 210. In the example shown in FIGS. 16 and 17, the sealant layer 212 is formed by bonding a thermoplastic resin film to the barrier laminate film 205 via the first adhesive layer 213. Although not shown, the sealant layer 212 may be formed by extruding a thermoplastic resin onto the barrier laminate film 205.

As the material constituting the sealant layer 212, one or more resins selected from polyethylene such as low-density polyethylene, linear low-density polyethylene, and polypropylene can be used. Sealant layer 212 may be a single layer or multilayer. Further, the sealant layer 212 is preferably made of an unstretched film. Note that "unstretched" is a concept that includes not only a film that has not been stretched at all, but also a film that has been slightly stretched due to the tension applied during film formation.

By the way, a packaging container made of packaging material 210 including sealant layer 212 is sometimes subjected to sterilization treatment such as boiling treatment or retort treatment at high temperature. Therefore, the sealant layer 212 used has heat resistance that can withstand these high temperature treatments.

The melting point of the material constituting the sealant layer 212 is preferably 150°C or higher, more preferably 160°C or higher. By increasing the melting point of the sealant layer 212, it is possible to retort the packaging container at a high temperature, thereby shortening the time required for the retort treatment. Note that the melting point of the material forming the sealant layer 212 is lower than the melting point of the resin forming the base material 201.

When considered from the viewpoint of retort processing, a material containing propylene as a main component can be used as the material constituting the sealant layer 212, as in the case of the sealant layer 70 in the first embodiment described above.

Furthermore, when considering from the viewpoint of boiling processing, examples of the material constituting the sealant layer 212 include polyethylene, polypropylene, or a combination thereof, as in the case of the sealant layer 70 in the first embodiment described above. I can do it.

Preferably, sealant layer 212 includes a propylene-ethylene block copolymer, similar to the case of sealant layer 70 in the first embodiment described above. For example, the sealant film including the sealant layer 212 is an unstretched film containing a propylene/ethylene block copolymer as a main component. By using a propylene/ethylene block copolymer, the impact resistance of the sealant film can be increased, and thereby the packaging container can be prevented from breaking due to impact when dropped. Furthermore, the puncture resistance of the packaging material 210 can be improved.

Moreover, the sealant layer 212 may further contain a thermoplastic elastomer, as in the case of the sealant layer 70 in the first embodiment described above. By using a thermoplastic elastomer, the impact resistance and puncture resistance of the sealant film can be further improved.

The content of the propylene/ethylene block copolymer in the sealant layer 212 is, for example, 80% by mass or more, and preferably 90% by mass or more.

A method for producing a propylene/ethylene block copolymer includes a method of polymerizing raw materials such as propylene and ethylene using a catalyst. As the catalyst, a Ziegler-Natta type catalyst, a metallocene catalyst, or the like can be used.

The sealant layer 212 may have easy-peel properties. Easy-peel property refers to the fact that when a lid material for a container is constructed using, for example, a packaging material 210 having a sealant layer 212, the lid material easily peels off from the flange portion of the container at the lower surface, that is, at the sealant layer 212. It is a characteristic. Easy peelability can be achieved, for example, by forming the sealant layer 212 with two or more types of resin and making one resin incompatible with the other resin. Examples of resins that can exhibit easy-peel properties include mixed resins of polyethylene and polypropylene, such as high-density polyethylene.

When the sealant layer 212 has easy-peel properties, the sealant layer 212 may include a first layer 2121 and a second layer 2122, as shown in FIG. In this case, the first layer 2121 may be a layer containing a mixture of polypropylene and high density polyethylene. Further, the second layer 2122 may be a layer made of polypropylene or high-density polyethylene. Such a sealant layer 212 can be formed by laminating a coextruded film including a first layer 2121 and a second layer 2122 to the barrier laminate film 205. When the second layer 2122 is made of polypropylene, the sealant layer 212 including the first layer 2121 and the second layer 2122 has heat resistance that can withstand heat treatment up to, for example, 135°C. Further, when the second layer 2122 is made of high-density polyethylene, the sealant layer 212 including the first layer 2121 and the second layer 2122 has heat resistance that can withstand heat treatment up to, for example, 123°C.

The sealant layer 212 may or may not contain a biomass-derived component. When forming the sealant layer 212 using a material containing a biomass-derived component, the sealant layer 212 can be formed using the following biomass polyolefin. Furthermore, when forming the sealant layer 212 using a material that does not contain biomass-derived components, the sealant layer 212 can be formed using a conventionally known fossil fuel-derived thermoplastic resin. Similarly, the sealant layer 70 in the first embodiment described above may also contain a biomass-derived component, which will be described later, or may not contain a biomass-derived component.

Biomass polyolefin is a polymer of monomers containing olefins such as ethylene derived from biomass. Since biomass-derived olefin is used as the raw material monomer, the polymerized polyolefin is biomass-derived. Note that the raw material monomer for the polyolefin does not have to contain 100% by mass of biomass-derived olefin.

For example, biomass-derived ethylene can be produced using biomass-derived ethanol as a raw material. In particular, it is preferable to use fermented ethanol derived from biomass obtained from plant materials. The plant raw material is not particularly limited, and conventionally known plants can be used. For example, corn, sugar cane, beets and manioc may be mentioned.

Fermented ethanol derived from biomass refers to ethanol produced by contacting a culture solution containing a carbon source obtained from a plant material with a product derived from an ethanol-producing microorganism or its crushed product, and then purified. Conventionally known methods such as distillation, membrane separation, and extraction can be applied to purify ethanol from the culture solution. For example, methods include adding benzene, cyclohexane, etc. and azeotropically distilling the mixture, or removing water by membrane separation or the like.

The monomer that is the raw material for the biomass polyolefin may further contain a fossil fuel-derived ethylene monomer and/or a fossil fuel-derived α-olefin monomer, or may further contain a biomass-derived α-olefin monomer.

The number of carbon atoms of the above α-olefin is not particularly limited, but those having 3 to 20 carbon atoms can be used, and butylene, hexene, or octene is preferable. This is because butylene, hexene, or octene can be produced by polymerizing ethylene, which is a raw material derived from biomass. Further, by including such an α-olefin, the polymerized polyolefin has an alkyl group as a branched structure, and therefore can be made more flexible than a simple linear one.

As the biomass polyolefin, polyethylene or a copolymer of ethylene and α-olefin may be used alone, or two or more types may be used as a mixture. In particular, the biomass polyolefin is preferably polyethylene. This is because by using ethylene, which is a biomass-derived raw material, it is theoretically possible to manufacture with 100% biomass-derived components.

The biomass polyolefin may contain two or more kinds of biomass polyolefins having different biomass degrees, and the biomass degree of the entire polyolefin resin layer may be within the range described below.

The biomass polyolefin is preferably 0.91 g/cm ³ or more and 0.93 g/cm 3 or less, more preferably 0.912 g/cm ^{3 or} more and 0.928 g/cm ³ or less, and even more preferably 0.915 g/cm 3 or more and 0.928 g/cm ³ or less. It has a density of .925 g/cm ³ or less. The density of the biomass polyolefin is a value measured according to the method specified in Method A of JIS K7112-1980 after performing annealing as described in JIS K6760-1995. If the density of the biomass polyolefin is 0.91 g/cm ³ or more, the rigidity of the polyolefin resin layer containing the biomass polyolefin can be increased, and it can be suitably used as an inner layer of a packaged product. Further, if the density of the biomass polyolefin is 0.93 g/cm ³ or less, the transparency and mechanical strength of the polyolefin resin layer containing the biomass polyolefin can be improved, and it can be suitably used as an inner layer of a packaged product.

The biomass polyolefin has a melt flow of 0.1 g/10 minutes or more and 10 g/10 minutes or less, preferably 0.2 g/10 minutes or more and 9 g/10 minutes or less, and more preferably 1 g/10 minutes or more and 8.5 g/10 minutes or less. rate (MFR). The melt flow rate is a value measured by method A under conditions of a temperature of 190° C. and a load of 21.18 N in the method specified in JIS K7210-1995. If the MFR of the biomass polyolefin is 0.1 g/10 minutes or more, the extrusion load during molding can be reduced. Moreover, if the MFR of the biomass polyolefin is 10 g/10 minutes or less, the mechanical strength of the polyolefin resin layer containing the biomass polyolefin can be increased.

Suitably used biomass polyolefins include biomass-derived low-density polyethylene manufactured by Braskem (trade name: SBC818, density: 0.918 g/cm ³ , MFR: 8.1 g/10 min, biomass degree 95%); Low-density polyethylene derived from biomass manufactured by Braskem (product name: SPB681, density: 0.922 g/cm ³ , MFR: 3.8 g/10 min, biomass degree 95%), linear chain derived from biomass manufactured by Braskem Examples include low-density polyethylene (trade name: SLL118, density: 0.916 g/cm ³ , MFR: 1.0 g/10 min, biomass degree 87%).

Examples of the fossil fuel-derived thermoplastic resins include low-density polyethylene, linear low-density polyethylene, medium-density polyethylene, high-density polyethylene, polypropylene, propylene-ethylene copolymer, ethylene-vinyl acetate copolymer, Examples include ethylene-acrylic acid copolymer, ethylene-methacrylic acid copolymer, ethylene-methyl acrylate copolymer, ethylene-ethyl acrylate copolymer, ethylene-methyl methacrylate copolymer, and ionomer.

The sealant layer 212 preferably has a biomass degree of 5% or more, more preferably 5% or more and 60% or less, and even more preferably 10% or more and 60% or less. If the biomass degree is within the above range, the amount of fossil fuel used can be reduced and the environmental load can be reduced.

Sealant layer 212 may be a single layer or multiple layers, as described above. When using a biomass polyolefin as described above for the sealant layer, the sealant layer may include three layers: an inner layer, an intermediate layer, and an outer layer. In that case, the intermediate layer may be a layer made of biomass polyolefin or a layer made of a mixture of biomass polyolefin and a conventionally known fossil fuel-derived polyolefin, and the inner layer and the outer layer may be made of a conventionally known fossil fuel-derived polyolefin. preferable.

The thickness of the sealant layer 212 is preferably 30 μm or more, more preferably 40 μm or more. Further, the thickness of the sealant layer 212 is preferably 100 μm or less, more preferably 80 μm or less.

[Adhesive layer]
The first adhesive layer 213 is a layer that adheres the barrier laminate film 205 and the film including the sealant layer 212. The first adhesive layer 213 is an adhesive layer or an adhesive resin layer. The adhesive layer and the adhesive resin layer will be explained below.

The adhesive layer can be formed by a conventionally known method, for example, a dry lamination method. When adhering two layers by dry lamination, the adhesive layer is formed by applying an adhesive to the surface of the layer to be laminated and drying it. Adhesives to be applied include, for example, one-component or two-component hardening or non-curing vinyl-based, (meth)acrylic-based, polyamide-based, polyester-based, polyether-based, polyurethane-based, epoxy-based, rubber. Solvent-based, water-based, or emulsion-based adhesives can be used. As the two-component curing adhesive, a cured product of a polyol and an isocyanate compound can be used. Coating methods for the above laminating adhesive include, for example, a direct gravure roll coating method, a gravure roll coating method, a kiss coating method, a reverse roll coating method, a Fontaine method, a transfer roll coating method, and other methods. . The adhesive layer after drying has a thickness of, for example, 1 μm or more and 10 μm or less, preferably 2 μm or more and 5 μm or less.

The adhesive layer may contain a biomass-derived component. For example, when the adhesive layer contains a cured product of a polyol and an isocyanate compound, at least either the polyol or the isocyanate compound may contain a biomass-derived component. Thereby, the biomass degree of the packaging material 210 can be further improved.

The adhesive resin layer contains a thermoplastic resin. The adhesive resin layer can be formed by a conventionally known method, such as a melt extrusion lamination method or a sand lamination method. Thermoplastic resins that can be used for the adhesive resin layer include polyethylene resins, polypropylene resins, cyclic polyolefin resins, copolymer resins, modified resins, and mixtures (including alloys) containing these resins as main components. ) can be used. Examples of polyolefin resins include low density polyethylene (LDPE), medium density polyethylene (MDPE), high density polyethylene (HDPE), linear low density polyethylene (LLDPE), polypropylene (PP), and metallocene catalysts. Ethylene-α olefin copolymer polymerized using Ethyl acrylate copolymer (EEA), ethylene-methacrylic acid copolymer (EMAA), ethylene-methyl methacrylate copolymer (EMMA), ethylene-maleic acid copolymer, ionomer resin, and interlayer adhesion In order to improve this, it is possible to use acid-modified polyolefin resins in which the above-mentioned polyolefin resins are modified with unsaturated carboxylic acids such as acrylic acid, methacrylic acid, maleic acid, maleic anhydride, fumaric acid, and itaconic acid. can. Further, a resin obtained by graft polymerizing or copolymerizing an unsaturated carboxylic acid, an unsaturated carboxylic acid anhydride, or an ester monomer to the polyolefin resin can be used. These materials can be used alone or in combination of two or more. As the cyclic polyolefin resin, for example, cyclic polyolefins such as ethylene-propylene copolymer, polymethylpentene, polybutene, and polynorbornene can be used. These resins can be used alone or in combination. The adhesive resin layer has a thickness of, for example, 5 μm or more and 50 μm or less, preferably 10 μm or more and 30 μm or less.

Note that as the above-mentioned polyethylene resin, one using biomass-derived ethylene as a monomer unit as described in the sealant layer 212 may be used. Thereby, the biomass degree of the packaging material 210 can be further improved.

[Printing layer]
The printing layer 218 is printed with letters, numbers, pictures, figures, and symbols for decoration, display of contents and packaged products, display of expiry date, display of manufacturer, seller, etc., and for imparting aesthetic appeal. , a layer that forms any desired printed pattern such as a pattern. The printed layer 218 can be provided as needed, and can be provided on the barrier laminate film 205, for example. The printed layer 218 may be provided on the entire surface of the film, or may be provided on a portion of the film. The printing layer 218 can be formed using conventionally known pigments and dyes, and the method of forming it is not particularly limited.

The printed layer 218 preferably has a thickness of 0.1 μm or more and 10 μm or less, more preferably 1 μm or more and 5 μm or less, and even more preferably 1 μm or more and 3 μm or less.

Print layer 218 may contain a biomass-derived component. For example, when the printing layer 218 contains a cured product of a polyol and an isocyanate compound, at least either the polyol or the isocyanate compound may contain a biomass-derived component.

<Method for manufacturing packaging materials>
Next, an example of a method for manufacturing the packaging material 210 will be described. First, an example of a method for manufacturing the barrier laminate film 205 will be described.

(Production process of barrier laminated film)
First, a base material 201 is prepared. Subsequently, a vapor deposition layer 202 containing aluminum oxide is formed on the surface of the base material 201. FIG. 20 is a diagram showing an example of a film forming apparatus 260. The film forming apparatus 260 and the film forming method using the film forming apparatus 260 will be described below.

As shown in FIG. 20, in the film forming apparatus 260, partition walls 285a to 285c are formed in the reduced pressure chamber 262. The partition walls 285a to 285c form a substrate transfer chamber 262A, a plasma pretreatment chamber 262B, and a film formation chamber 262C, and in particular, a plasma pretreatment chamber 262B and a film formation chamber are defined as spaces surrounded by the partition walls 285a to 285c. 262C is formed, and each chamber is further formed with an exhaust chamber therein as required.

The plasma pretreatment chamber 262B and the plasma pretreatment process in the plasma pretreatment chamber 262B will be described. Inside the plasma pretreatment chamber 262B, a part of a plasma pretreatment roller 270 that conveys the substrate 201 to be pretreated and enables plasma treatment is provided so as to be exposed to the substrate conveyance chamber 262A. There is. The base material 201 moves to the plasma pretreatment chamber 262B while being wound up.

The plasma pretreatment chamber 262B and the film forming chamber 262C are provided in contact with the substrate transfer chamber 262A, and can be moved without exposing the substrate 201 to the atmosphere. Further, the pretreatment chamber 262B and the substrate transfer chamber 262A are connected through a rectangular hole, and a part of the plasma pretreatment roller 270 protrudes toward the substrate transfer chamber 262A through the rectangular hole. A gap is formed between the wall of the transfer chamber and the pretreatment roller 270, and the base material 201 can be moved from the substrate transfer chamber 262A to the film forming chamber 262C through the gap. The structure is similar between the base material transfer chamber 262A and the film forming chamber 262C, and the base material 201 can be moved without being exposed to the atmosphere.

The base material transport chamber 262A serves as a winding means in order to wind up the base material 201, on which the vapor deposition layer 202 is formed on one side, into a roll, which has been moved again to the base material transport chamber 212A by the film forming roller 275. A take-up roller is provided so that the base material 201 on which the vapor deposition layer 202 is formed can be taken up.

When manufacturing the barrier laminated film 205 having the vapor deposited layer 202 containing aluminum oxide, the plasma pretreatment chamber 262B separates the space where plasma is generated from other areas so that the opposing space can be efficiently evacuated. With this configuration, it becomes easy to control the plasma gas concentration, and productivity is improved. The pretreatment pressure formed by reducing the pressure can be set and maintained at about 0.1 Pa to 100 Pa. In particular, in order to achieve a preferable metamorphosis rate in the transition region of the vapor deposited layer 202 containing aluminum oxide, the oxygen plasma pretreatment is performed. The processing pressure is preferably 1 to 20 Pa.

The conveyance speed of the base material 201 is not particularly limited, but from the viewpoint of production efficiency, it can be at least 200 to 1000 m/min. The transport speed for plasma pretreatment is preferably 300 to 800 m/min.

The plasma pretreatment roller 270 constituting the plasma pretreatment device prevents the substrate 201 from shrinking or being damaged due to heat during plasma treatment by the plasma pretreatment means, and applies oxygen plasma P uniformly and over a wide range to the substrate 201. It is intended to be applied to Preferably, the temperature of the pretreatment roller 270 can be adjusted to a constant temperature between -20° C. and 100° C. by adjusting the temperature of a temperature adjusting medium circulating within the pretreatment roller.

The plasma pretreatment means includes a plasma supply means and a magnetic formation means. The plasma pretreatment means cooperates with the plasma pretreatment roller 270 to confine oxygen plasma P near the surface of the base material 201.

The plasma pretreatment means is provided so as to partially cover the pretreatment roller 270. Specifically, plasma supply means 272 and magnetic formation means 273, which constitute plasma pretreatment means, are arranged along the surface near the outer periphery of pretreatment roller 270. The plasma supply means 272 includes a plasma supply nozzle that supplies plasma source gas. The magnetic formation means 273 includes a magnet or the like to promote generation of plasma P. Further, the plasma pretreatment means includes an electrode 271 to which a voltage is applied between the pretreatment roller 270 and the electrode 271 . Note that although FIG. 20 shows an example in which the electrode 271 and the plasma supply means 272 are separate members, the present invention is not limited to this. Although not shown, the electrode 271 and the plasma supply means 272 may be configured as an integral member.

By generating plasma P in the space sandwiched between the pretreatment roller 270 and the magnetic formation means 273 and forming a region with high plasma density near the surfaces of the pretreatment roller 270 and the base material 201, the base material 201 The inner surface of the substrate can be subjected to oxygen plasma pretreatment to form a plasma treated surface.

The plasma supply means 272 of the plasma pretreatment means includes a source gas volatilization supply device 268 connected to a plasma supply nozzle provided outside the decompression chamber 262, and a source gas supply line that supplies source gas from the device. The plasma raw material gas to be supplied is oxygen alone or a mixed gas of oxygen gas and an inert gas, and is supplied from the gas storage section through a flow rate controller while measuring the flow rate of the gas. Examples of the inert gas include one or more mixed gases selected from the group consisting of argon, helium, and nitrogen.

These supplied gases are mixed at a predetermined ratio as necessary to form a plasma raw material gas alone or a mixed gas for plasma formation, and are supplied to the plasma supply means. The single or mixed gas is supplied to a plasma supply nozzle of the plasma supply means, and is supplied near the outer periphery of the pretreatment roller 270 where the supply port of the plasma supply nozzle opens. The nozzle opening is directed toward the base material 201 on the pretreatment roller 270, and is arranged and configured so that the oxygen plasma P can be uniformly diffused and supplied to the entire surface of the base material 201. Thereby, uniform plasma pretreatment can be applied to a large area of the base material 201.

In order to set the metamorphosis rate of the transition region of the vapor deposited layer 202 containing aluminum oxide to 5% or more and 60% or less as described above, the oxygen plasma pretreatment is performed by adjusting the mixing ratio of oxygen gas and inert gas (oxygen gas/inert gas). active gas) is preferably 6/1 to 1/1, more preferably 5/2 to 3/2. By setting the mixing ratio to 6/1 to 1/1, the film formation energy of the vapor deposited layer 202 on the base material 201 increases, and by setting the mixing ratio to 5/2 to 3/2, the formation of aluminum hydroxide increases. is formed near the interface of the base material, that is, the metamorphism rate of the transition region decreases.

Electrode 271 functions as a counter electrode of pretreatment roller 270. The plasma raw material gas supplied is excited due to the potential difference due to the high frequency voltage, low frequency voltage, etc. supplied between the pretreatment roller 270 and the plasma P, which is generated and supplied.

Specifically, for the electrode 271, a plasma pretreatment roller is installed as a plasma power source, and an alternating current voltage with a frequency of 10 Hz to 2.5 GHz is applied between the electrode 271 and the opposing electrode to control input power, impedance, etc. , and the plasma pretreatment roller 270 can be applied with any voltage. The film forming apparatus 260 includes a power source 282 that can apply a bias voltage to bring the oxygen plasma P, which can physically or chemically modify the surface properties of the base material 201, to a positive potential.

The plasma intensity per unit area is preferably 50 to 8000 W·sec/m ² . At less than 50 W·sec/m ² , no effect of plasma pretreatment is observed, and at more than 8000 W·sec/m ² , deterioration of the base material 201 due to plasma occurs, such as consumption of the base material 201, damage and coloring, and baking. There is a tendency. In particular, the plasma intensity per unit area is preferably 100 to 1000 W·sec/m ² . By applying a bias voltage perpendicular to the base material 201 and applying the above plasma intensity, it is possible to stably improve the adhesion with the vapor deposited layer 202 containing aluminum oxide.

As the magnetism forming means 273, it is possible to use one in which an insulating spacer and a base plate are provided in a magnet case, and a magnet is provided on the base plate. An insulating shield plate is provided in the magnet case, and an electrode can be attached to this insulating shield plate. The magnet case and the electrodes are electrically insulated, and even if the magnet case is installed and fixed in the decompression chamber 262, the electrodes can be kept at an electrically floating level. By providing the magnet, the reactivity near the surface of the base material 201 becomes high, and it becomes possible to form a good plasma pretreated surface at high speed.

Preferably, the magnet is configured such that the magnetic flux density at the surface of the base material 201 is from 10 Gauss to 10,000 Gauss. If the magnetic flux density on the surface of the base material 201 is 10 Gauss or more, it becomes possible to sufficiently increase the reactivity near the surface of the base material 201, and a good pretreated surface can be formed at high speed.

Next, the film forming process in the film forming chamber 262C and the film forming chamber 262C will be explained. The film forming apparatus 260 includes a film forming roller 275 arranged in a reduced pressure film forming chamber 262C, and a target of a vapor deposition film forming means 274 arranged opposite to the film forming roller 275. The film forming roller 275 wraps and conveys the base material 201, which has been pretreated in the plasma pretreatment device, with the treated surface of the base material 201 facing outward. In the film forming process, the target of the vapor deposition film forming means 274 is evaporated to form an aluminum oxide film on the surface of the base material 201.

The vapor deposition film forming means 274 is, for example, a resistance heating type, uses an aluminum metal wire as an evaporation source, supplies oxygen to oxidize the aluminum vapor, and oxidizes the surface of the base material 201 to contain aluminum oxide. A vapor deposition layer 202 is formed.

The thickness of the vapor deposition layer 202 containing aluminum oxide formed as described above is preferably 3 to 50 nm, more preferably 9 to 30 nm. Within this range, barrier properties can be maintained. However, if the deposited layer 202 containing aluminum oxide is very thin, it becomes difficult to calculate the metamorphosis rate of the transition region by TOF-SIMS measurement.

Next, a method for forming the gas barrier coating film 203 on the vapor deposition layer 202 will be explained. First, the metal alkoxide, silane coupling agent, hydroxyl group-containing water-soluble resin, reaction promoter (sol-gel method catalyst, acid, etc.), and an organic solvent such as water, methyl alcohol, ethyl alcohol, isopropanol, etc. as a solvent are first added. By mixing, a coating agent for a gas barrier coating film made of a resin composition is prepared.

When the gas barrier coating film 203 contains a silane coupling agent, the coating agent for the gas barrier coating film may be prepared as follows. First, a metal alkoxide such as alkoxysilane and a silane coupling agent are mixed. The metal alkoxide and the silane coupling agent are preferably mixed at 10°C or lower. Thereby, the film structure of the gas barrier coating film 203 that is formed tends to be dense. Subsequently, a mixture of a metal alkoxide and a silane coupling agent and a hydroxyl group-containing water-soluble resin such as a polyvinyl alcohol resin are mixed.

After preparing the coating agent for a gas barrier coating film, the above coating agent for a gas barrier coating film is applied onto the vapor deposited layer 202 by a conventional method and dried. Through this drying step, the condensation or co-condensation reaction further advances and a coating film is formed. The above coating operation may be further repeated on the first coating film to form a plurality of coating films consisting of two or more layers.

Further, heat treatment is performed at a temperature in the range of 20 to 200°C, preferably 50 to 180°C, and at a temperature below the softening point of the resin constituting the base material 201 for 3 seconds to 10 minutes. As a result, a gas barrier coating film 203 made of the gas barrier coating film coating agent described above can be formed on the vapor deposition layer 202 . In this way, a barrier laminate film 205 having a base material 201, a vapor deposited layer 202, and a gas barrier coating film 203 can be produced.

(Lamination process)
Next, a method for manufacturing the above-mentioned packaging material 210 by laminating the sealant layer 212 on the barrier laminated film 205 will be described.

First, the barrier laminate film 205 is prepared, and the printed layer 218 is formed on the gas barrier coating film 203 of the barrier laminate film 205 by, for example, gravure printing. Further, a film constituting the sealant layer 212 is prepared. Thereafter, by a dry lamination method, the film containing the barrier laminate film 205 and the film constituting the sealant layer 212 are bonded via the first adhesive layer 213 made of an adhesive layer. In this way, packaging material 210 can be obtained.

<Packaged products>
Examples of packaging products formed by using the packaging material 210 include the bag 10 shown in FIGS. 1, 13, and 14, and the bags 10 shown in FIGS. Examples include the lid material 114 of the lidded container 110 shown in FIG.

The bag of the packaging product is made by folding the packaging material 210 in half or by preparing two sheets of the packaging material 210 and making the sealant layer 212 of the packaging material 210 on the front side and the sealant layer 212 of the packaging material 210 on the back side face each other. Overlap, and then add the surrounding edges to, for example, side seal type, two side seal type, three side seal type, four side seal type, envelope pasting seal type, gasho pasting seal type (pillow seal type), pleated seal type, flat bottom seal type. Various types of packaging bags can be manufactured by heat sealing using heat sealing methods such as a sealed type and a square bottom sealed type. Furthermore, a gusset-type packaging bag can also be manufactured by heat-sealing the folded packaging material 210 inserted between the front packaging material 210 and the back packaging material 210. Note that not all of the packaging material 210 constituting the packaging bag may be the packaging material 210 according to the present invention. That is, at least a portion of the packaging material 210 constituting the packaging bag may be a packaging material 210 that includes a barrier laminated film 205 having a base material 201 containing a high stiffness PET film or a PBT film, and the packaging constituting the packaging bag. Other portions of material 210 may be packaging material 210 that does not include barrier laminate film 205.

As the heat sealing method, for example, known methods such as bar sealing, rotating roll sealing, belt sealing, impulse sealing, high frequency sealing, and ultrasonic sealing can be used.

At least one of the films such as the front film 14, back film 15, and lower film 16 constituting the bag 10 as shown in FIGS. 1, 13, and 14 is a base material containing a high stiffness PET film or PBT film. The packaging material 210 includes a barrier laminated film 205 having a barrier film 201. Thereby, gas barrier properties and strength can be imparted to the bag 10. Similarly, the lid material 114 constituting the lidded container 110 as shown in FIGS. 15A and 15B is composed of a packaging material 210 including a barrier laminated film 205 having a base material 201 containing a high stiffness PET film or PBT film. You can also. Thereby, gas barrier properties and strength can be imparted to the lidded container.

Next, the present invention will be explained in more detail with reference to examples, but the present invention is not limited to the description of the following examples unless it exceeds the gist thereof.

Using Examples A1 to A3, Reference Examples A4 to A5 , and Comparative Examples A1 to A2, the puncture strength, tearability, and heat resistance of the packaging material 30 of the present invention were evaluated.

(Example A1)
As the stretched plastic film 60, a high stiffness polyester film (hereinafter also referred to as high stiffness PET film) made of PET and having a loop stiffness of 0.0017 N or more was prepared. Subsequently, a printing layer 36 having a thickness of 1 μm was formed on the surface of the high stiffness PET film.
Specifically, as the high stiffness PET film, XP-55 manufactured by Toray Industries, Inc. was used. The thickness of the high stiffness PET film was 16 μm. Furthermore, the measured loop stiffness of the high stiffness PET film was 0.0021N in both the machine direction and the vertical direction. Further, the tensile modulus of the high stiffness PET film in the machine direction was 4.8 GPa, and the tensile modulus of the high stiffness polyester film in the vertical direction was 4.7 GPa.
Further, the tensile strength of the high stiffness PET film in the machine direction was 292 MPa, and the tensile strength of the high stiffness polyester film in the vertical direction was 257 MPa. Further, the tensile elongation of the high stiffness PET film in the machine direction was 107%, and the tensile elongation of the high stiffness polyester film in the vertical direction was 102%. In this case, the tensile strength of the high stiffness PET film in the machine direction divided by the tensile elongation is 2.73 [MPa/%], and the tensile strength of the high stiffness PET film in the vertical direction divided by the tensile elongation is 2.73 [MPa/%]. The value is 2.52 [MPa/%].
Further, the heat shrinkage rate of the high stiffness PET film in both the flow direction and the vertical direction was 0.4%.

Further, as the sealant layer 70, an unstretched polypropylene film ZK500 manufactured by Toray Film Kako Co., Ltd. was prepared. ZK500 includes the propylene-ethylene block copolymer and elastomer described above. The thickness of the sealant layer 70 was 60 μm.

ZK500 has a higher tensile elongation than a typical unstretched polypropylene film. Specifically, the tensile elongation of ZK500 in the machine direction (MD) is 1180% when the thickness is 50 μm, and 1100% when the thickness is 60 μm. Further, the tensile elongation of ZK500 in the vertical direction (TD) is 1240% when the thickness is 50 μm, and 1150% when the thickness is 60 μm. Therefore, the product of tensile elongation (%) and thickness (μm) of ZK500 in the machine direction is 59,000 when the thickness is 50 μm, and 66,000 when the thickness is 60 μm. Further, the product of tensile elongation (%) and thickness (μm) of ZK500 in the vertical direction is 62,000 when the thickness is 50 μm, and 69,000 when the thickness is 60 μm.

Additionally, ZK500 has a lower tensile modulus than a typical unstretched polypropylene film. Specifically, the tensile modulus of ZK500 in the machine direction (MD) is 640 MPa when the thickness is 50 μm, and 550 MPa when the thickness is 60 μm. Further, the tensile modulus of ZK500 in the vertical direction (TD) is 480 MPa when the thickness is 50 μm, and 400 MPa when the thickness is 60 μm. Therefore, the product of the tensile modulus (MPa) and the thickness (μm) of ZK500 in the machine direction is 32,000 when the thickness is 50 μm, and 33,000 when the thickness is 60 μm. Further, the product of the tensile modulus (MPa) and thickness (μm) of ZK500 in the vertical direction is 24,000 when the thickness is 50 μm, and 35,000 when the thickness is 60 μm.

Subsequently, the stretched plastic film 60 and the sealant layer 70 were laminated by a dry lamination method to produce the packaging material 30. The printed layer 36 was laminated so as to face the side of the sealant layer 70. As the adhesive layer 65, a two-component polyurethane adhesive (base resin: RU-40, curing agent: H-4) manufactured by Rock Paint Co., Ltd. was used. Note that the main ingredient RU-40 is a polyester polyol. The thickness of the adhesive layer 65 was 3.5 μm. The overall thickness of the packaging material 30 was 80.5 μm.

[Evaluation of puncture resistance]
Subsequently, the puncture strength of the packaging material 30 was measured in accordance with JIS Z1707 7.4. As a measuring instrument, Tensilon universal material testing machine RTC-1310 manufactured by A&D was used. Specifically, as shown in FIG. 21, a semicircular needle 90 with a diameter of 1.0 mm and a tip radius of 0.5 mm is inserted from the outer surface 30y side into a test piece of the packaging material 30 in a fixed state. was pierced at a speed of 50 mm/min (50 mm per minute), and the maximum stress until the needle 90 penetrated the packaging material 30 was measured. The maximum value of stress was measured for five or more test pieces, and the average value was taken as the puncture strength of the packaging material 30. The environment during measurement was a temperature of 23° C. and a relative humidity of 50%. As a result, the puncture strength was 13.0N.

[Evaluation of loop stiffness]
In addition, the loop stiffness of the packaging material 30 in the flow direction and the vertical direction was measured. As a measuring device, No. 1 manufactured by Toyo Seiki Co., Ltd. is used. 581 Loop Stiffness Tester (registered trademark) LOOP STIFFNESS TESTER DA type was used. The environment during measurement was a temperature of 23° C. and a relative humidity of 50%. As a result, the loop stiffness of the packaging material 30 in the flow direction was 0.082N, and the loop stiffness in the vertical direction was 0.077N. In this case, the value obtained by dividing the loop stiffness in the flow direction of the packaging material 30 by the thickness of the packaging material 30 is 0.00102N/μm, and the value obtained by dividing the loop stiffness in the vertical direction by the thickness of the packaging material 30 is 0.00096N. /μm.

[Evaluation of impact resistance]
Further, two packaging materials 30 were stacked and heated at 190° C. for 1 second to heat-seal the inner surfaces 30x of the packaging materials 30 to each other. Next, the two heat-sealed packaging materials 30 were cut out to a width of 15 mm to prepare a test piece 100. 22 is a plan view showing the test piece 100, and FIG. 23 is a cross-sectional view of the test piece 100 in FIG. 22. The test piece 100 has a width V1 of 15 mm and a length V2 of 50 mm, and a seal portion 101 is formed over a length V3 of 10 mm from one end and over a length of 40 mm from the other end. A seal portion is not formed. Subsequently, as shown in FIG. 24, the unsealed portion of one packaging material 30 and the unsealed portion of the other packaging material 30 are oriented in opposite directions to each other in a direction perpendicular to the surface direction of the sealed portion 101. After shaping the unsealed portion of one packaging material 30 and the unsealed end of the other packaging material 30 with a jig 102, , 103. At this time, the distance N between the jigs 102 and 103 in the direction orthogonal to the surface direction of the seal portion 101 was set to 40 mm. Subsequently, one jig 102 is struck with a hammer 104 from the surface of one packaging material 30 on the first stretched plastic film 40 side, so that one packaging material 30 and the other packaging material 30 are separated. The impact strength was measured. As a measuring device, a digital impact tester manufactured by Toyo Seiki Seisakusho Co., Ltd. was used for evaluation. A 2J hammer was used to apply an impact to the test piece 100. As a result, the impact strength was 374 kJ/m.

[Evaluation of tearability]
Further, as shown in FIG. 25, the two packaging materials 30 bonded together via the sealant layer 70 were cut out to have a width V4 of 15 mm and a length V5 of 100 mm to prepare a test piece 95. The direction of the width V4 of the test piece 95 is parallel to the second direction D2 shown in FIG. Further, the direction of the length V5 of the test piece 95 is parallel to the flow direction (MD) when forming a film such as a stretched plastic film or a sealant film, and is also parallel to the first direction D1 shown in FIG. It is. Subsequently, as shown in FIG. 25, a cut 28 was formed in the center of the test piece 95 in the width V4 direction. Subsequently, the test piece 95 was torn by hand in the direction of length V5 starting from the notch 28. As a result, the test piece 95 could be torn in the direction of length V5 without the sealant layer 70 of the packaging material 30 stretching during the tearing.

[Evaluation of openability and heat resistance]
Subsequently, a bag 10 was produced using the packaging material 30, and the openability and heat resistance of the bag 10 were evaluated. Specifically, first, the bag 10 shown in FIG. 13 was produced using the packaging material 30. The height S1 of the bag 10 was 145 mm, and the width S2 was 150 mm. Moreover, the height S3 of the folded lower film 16, that is, the height from the lower end of the bag 10 to the folded part 16f, was 43 mm. In the following description, the bag 10 having a height S1 of 145 mm, a width S2 of 150 mm, and a height S3 of 43 mm will also be referred to as a medium-sized bag 10. Subsequently, 100 g of contents containing a large amount of oil such as meat and miso were filled into the inside of the bag 10 through the opening 11b of the upper part 11. At this time, the openability of the opening 11b was evaluated. Specifically, as shown in FIG. 12, when a force P is applied from the side to the bag 10 using the chuck 111, the front film 14 and the back film 15 each have a curved shape that is convex toward the outer surface. It was confirmed whether or not it deformed as if it had a shape. As a result, the front film 14 and the back film 15 were deformed to have a curved shape convex toward the outer surface.

After filling the bag 10 with the contents, the upper part 11 was heat-sealed to form an upper sealed part 11a. Thereafter, the bag 10 containing the contents was heated for 2 minutes using a microwave oven with an output of 500 W, and it was confirmed whether or not the packaging material 30 constituting the bag 10 would be damaged. The test was conducted on 10 bags 10. As a result, it was confirmed that in 10 out of 10 bags 10, there was no damage such as holes in the packaging material 30 or wrinkles formed in the packaging material 30.

(Example A2)
A packaging material 30 was produced in the same manner as in Example A1, except that unstretched polypropylene film ZK207 manufactured by Toray Film Processing Co., Ltd. was used as the sealant layer 70. The thickness of the sealant layer 70 was 70 μm. The entire thickness of the packaging material 30 was 90.5 μm.

ZK207 has a high tensile modulus. Specifically, the tensile modulus of ZK207 in the machine direction (MD) is 780 MPa when the thickness is 50 μm, and 680 MPa when the thickness is 60 μm. Further, the tensile modulus of ZK207 in the vertical direction (TD) is 630 MPa when the thickness is 50 μm, and 560 MPa when the thickness is 60 μm. Therefore, the product of the tensile modulus (MPa) and thickness (μm) of ZK207 in the machine direction is 39,000 when the thickness is 50 μm and 40,800 when the thickness is 60 μm. Further, the product of the tensile modulus (MPa) and thickness (μm) of ZK207 in the vertical direction is 31500 when the thickness is 50 μm, and 33600 when the thickness is 60 μm.

ZK207 also has low tensile elongation. Specifically, the tensile elongation of ZK207 in the machine direction (MD) is 790% when the thickness is 50 μm and 730% when the thickness is 60 μm. Further, the tensile elongation of ZK207 in the vertical direction (TD) is 1020% when the thickness is 50 μm, and 870% when the thickness is 60 μm. Therefore, the product of tensile elongation (%) and thickness (μm) of ZK207 in the machine direction is 39,500 when the thickness is 50 μm and 43,800 when the thickness is 60 μm. Further, the product of tensile elongation (%) and thickness (μm) of ZK207 in the vertical direction is 51,000 when the thickness is 50 μm, and 52,200 when the thickness is 60 μm.

Subsequently, the puncture strength, impact strength, and loop stiffness of the packaging material 30 were measured in the same manner as in Example A1. As a result, the puncture strength was 13.2N, and the impact strength was 287kJ/m. The loop stiffness of the packaging material 30 in the machine direction was 0.091N, and the loop stiffness in the vertical direction was 0.088N. In this case, the value obtained by dividing the loop stiffness in the flow direction of the packaging material 30 by the thickness of the packaging material 30 is 0.00101N/μm, and the value obtained by dividing the loop stiffness in the vertical direction by the thickness of the packaging material 30 is 0.00097N. /μm.

Subsequently, the tearability of the packaging material 30 was evaluated in the same manner as in Example A1. As a result, the test piece 95 could be torn in the direction of length V5 without the sealant layer 70 of the packaging material 30 stretching during the tearing.

Subsequently, in the same manner as in Example A1, a bag 10 was produced using the packaging material 30, and the openability of the bag 10 when filling the bag 10 with contents was evaluated. The size of the bag 10 was M size as in Example A1. As a result, the front film 14 and the back film 15 were deformed to have a curved shape convex toward the outer surface. In addition, the heat resistance of the bag 10 containing the contents was evaluated in the same manner as in Example A1. As a result, it was confirmed that although wrinkles were formed in the packaging material 30, there were no holes in the packaging material 30.

(Example A3)
A packaging material 30 was produced in the same manner as in Example 1, except that unstretched polypropylene film ZK500R manufactured by Toray Film Processing Co., Ltd. was used as the sealant layer 70. The thickness of the sealant layer 70 was 50 μm. The overall thickness of the packaging material 30 was 70.5 μm.

ZK500R has a high tensile modulus. Specifically, the tensile modulus of ZK500R in the machine direction (MD) is 980 MPa when the thickness is 50 μm. Further, the tensile modulus of ZK500R in the vertical direction (TD) is 780 MPa when the thickness is 50 μm. Therefore, the product of the tensile modulus (MPa) and thickness (μm) of ZK500R in the machine direction is 49,000 when the thickness is 50 μm. Further, the product of the tensile modulus (MPa) and thickness (μm) of ZK500R in the vertical direction is 39,000 when the thickness is 50 μm.

ZK500R also has low tensile elongation. Specifically, the tensile elongation of ZK500R in the machine direction (MD) is 770% when the thickness is 50 μm. Further, the tensile elongation of ZK500R in the vertical direction (TD) is 870% when the thickness is 50 μm. Therefore, the product of the tensile elongation (%) and thickness (μm) of ZK500R in the machine direction is 38,500 when the thickness is 50 μm. Further, the product of the tensile elongation (%) and the thickness (μm) of ZK500R in the vertical direction is 43,500 when the thickness is 50 μm.

Subsequently, the puncture strength, impact strength, and loop stiffness of the packaging material 30 were measured in the same manner as in Example A1. As a result, the puncture strength was 13.6N, and the impact strength was 263kJ/m. The loop stiffness of the packaging material 30 in the flow direction was 0.067N, and the loop stiffness in the vertical direction was 0.057N. In this case, the value obtained by dividing the loop stiffness in the flow direction of the packaging material 30 by the thickness of the packaging material 30 is 0.00095N/μm, and the value obtained by dividing the loop stiffness in the vertical direction by the thickness of the packaging material 30 is 0.00081N. /μm.

Subsequently, the tearability of the packaging material 30 was evaluated in the same manner as in Example A1. As a result, the test piece 95 could be torn in the direction of length V5 without the sealant layer 70 of the packaging material 30 stretching during the tearing. Moreover, the amount of positional deviation in the width V4 direction of the two packaging materials 30 at the torn location was 5 mm or less.

Subsequently, in the same manner as in Example A1, a bag 10 was produced using the packaging material 30, and the openability of the bag 10 when filling the bag 10 with contents was evaluated. The size of the bag 10 was M size as in Example A1. As a result, the front film 14 and the back film 15 were deformed to have a curved shape convex toward the outer surface. In addition, the heat resistance of the bag 10 containing the contents was evaluated in the same manner as in Example A1. As a result, it was confirmed that although wrinkles were formed in the packaging material 30, there were no holes in the packaging material 30.

(Comparative example A1)
A packaging material 30 was produced in the same manner as in Example A2, except that two stretched PET films having a thickness of 12 μm bonded together by an adhesive layer were used as the base material 35. The entire thickness of the packaging material 30 was 102 μm.

Subsequently, the puncture strength and loop stiffness of the packaging material 30 were measured in the same manner as in Example A1. As a result, the puncture strength was 13.2N. The loop stiffness of the packaging material 30 in the machine direction was 0.102N, and the loop stiffness in the vertical direction was 0.095N. In this case, the value obtained by dividing the loop stiffness in the flow direction of the packaging material 30 by the thickness of the packaging material 30 is 0.00100N/μm, and the value obtained by dividing the loop stiffness in the vertical direction by the thickness of the packaging material 30 is 0.00093N. /μm.

Subsequently, the tearability of the packaging material 30 was evaluated in the same manner as in Example A1. As a result, the sealant layer 70 of the packaging material 30 stretched during the process, and the test piece 95 could not be torn in the direction of length V5.

Subsequently, in the same manner as in Example A1, a bag 10 was produced using the packaging material 30, and the openability of the bag 10 when filling the bag 10 with contents was evaluated. The size of the bag 10 was M size as in Example A1. As a result, the front film 14 and the back film 15 were deformed to have a curved shape convex toward the outer surface. In addition, the heat resistance of the bag 10 containing the contents was evaluated in the same manner as in Example A1. As a result, it was confirmed that although wrinkles were formed in the packaging material 30, there were no holes in the packaging material 30.

(Comparative example A2)
A packaging material 30 was produced in the same manner as in Example A2, except that a stretched PET film having a thickness of 12 μm was used as the stretched plastic film 60. The overall thickness of the packaging material 30 was 86.5 μm.

Subsequently, the puncture strength, impact strength, and loop stiffness of the packaging material 30 were measured in the same manner as in Example A1. As a result, the puncture strength was 11.1N, and the impact strength was 301kJ/m. The loop stiffness of the packaging material 30 in the machine direction was 0.071N, and the loop stiffness in the vertical direction was 0.069N. In this case, the value obtained by dividing the loop stiffness in the flow direction of the packaging material 30 by the thickness of the packaging material 30 is 0.00082N/μm, and the value obtained by dividing the loop stiffness in the vertical direction by the thickness of the packaging material 30 is 0.00080N. /μm.

Subsequently, the tearability of the packaging material 30 was evaluated in the same manner as in Example A1. As a result, the sealant layer 70 of the packaging material 30 stretched during the process, and the test piece 95 could not be torn in the direction of length W5.

Subsequently, in the same manner as in Example 1, a bag 10 was produced using the packaging material 30, and the openability when filling the bag 10 with contents was evaluated. The size of the bag 10 was M size as in Example A1. As a result, the front film 14 and the back film 15 are formed with a plurality of curved portions that are convex toward the outer surface, as well as a plurality of curved portions that are convex toward the inner surface, so that a sufficient opening width K is formed. could not be secured. In addition, the heat resistance of the bag 10 containing the contents was evaluated in the same manner as in Example A1. As a result, it was confirmed that although wrinkles were formed in the packaging material 30, there were no holes in the packaging material 30.

( Reference example A4)
The packaging material 30 was prepared in the same manner as in Example A1, except that a sealant film made of a mixed resin containing low-density polyethylene and linear low-density polyethylene and having a melting point of 105° C. was used as the sealant layer 70. was created. The thickness of the sealant layer 70 was 50 μm. The overall thickness of the packaging material 30 was 70.5 μm.

Subsequently, the puncture strength and loop stiffness of the packaging material 30 were measured in the same manner as in Example A1. As a result, the puncture strength was 12.1N. The loop stiffness of the packaging material 30 in the machine direction was 0.050N, and the loop stiffness in the vertical direction was 0.055N. In this case, the value obtained by dividing the loop stiffness in the flow direction of the packaging material 30 by the thickness of the packaging material 30 is 0.00071N/μm, and the value obtained by dividing the loop stiffness in the vertical direction by the thickness of the packaging material 30 is 0.00078N. /μm.

( Reference example A5)
The packaging material 30 was prepared in the same manner as in Example A1, except that as the sealant layer 70, a coextruded film having the first layer 71 and the second layer 72 shown in FIG. 11 and having easy peel properties was used. Created. The first layer 71 was a 45 μm thick layer made of polyethylene. The second layer 72 was a 5 μm thick layer containing a mixed resin of polyethylene and polypropylene. As the polyethylene, high-density polyethylene having a density of 0.950 g/cm3 was used. As the polypropylene, an ethylene-propylene random copolymer was used. The mass ratio of polypropylene to polyethylene in the second layer 72 was 7:3. The thickness of the sealant layer 70 was 50 μm. The overall thickness of the packaging material 30 was 70.5 μm.

Subsequently, the puncture strength and loop stiffness of the packaging material 30 were measured in the same manner as in Example A1. As a result, the puncture strength was 12.2N. The loop stiffness of the packaging material 30 in the machine direction was 0.053N, and the loop stiffness in the vertical direction was 0.052N. In this case, the value obtained by dividing the loop stiffness in the flow direction of the packaging material 30 by the thickness of the packaging material 30 is 0.00075 N/μm, and the value obtained by dividing the loop stiffness in the vertical direction by the thickness of the packaging material 30 is 0.00074 N. /μm.

The layer structures of Examples A1 to A3, Reference Examples A4 to A5 , and Comparative Examples A1 to A2, as well as evaluation results regarding puncture strength and loop stiffness, are summarized in FIG. 26. Furthermore, the layer structures of Examples A1 to A3 and Comparative Examples A1 to A2, as well as the evaluation results regarding impact strength, tearability, and heat resistance, are summarized in FIG. 27. In FIGS. 26 and 27, in the "layer structure" column, the constituent elements of the packaging material are listed in order from the top, starting from the outer layer. In addition, in the "heat resistance" column, if the packaging material 30 had no holes or wrinkles, it was written as "great," and if the packaging material 30 had wrinkles but no holes. If the packaging material 30 had holes and wrinkles, it was marked as "bad". In addition, in the "openability" column, if the front film 14 and the back film 15 are deformed to have a curved shape that is convex toward the outside, it is marked as "good", and the front film 14 and the back film 15 are marked as "good". In addition to a plurality of curved portions that are convex on the outer surface side, a plurality of curved portions that are convex on the inner surface side are also formed, and this is described as "bad."

As can be seen from the comparison of Examples A1 to A3, Reference Examples A4 to A5, and Comparative Example A2, by using a high stiffness polyester film as the stretched plastic film 60, only one stretched plastic film is included in the packaging material 30. Even in this case, the puncture strength of the packaging material 30 could be increased to 12N or more, for example, 13N or more. As can be seen from Comparative Example A1, such puncture strength is equivalent to the case where the packaging material 30 includes two stretched plastic films.

Furthermore, as can be seen from the comparison between Examples A1 to A3 and Comparative Example A2, by using a high stiffness polyester film as the stretched plastic film 60, even when only one stretched plastic film is included in the packaging material 30. Also, in at least one direction, the value obtained by dividing the loop stiffness of the packaging material 30 by the thickness of the packaging material 30 is set to 0.00085 N/μm or more, for example, 0.00090 N/μm or more, 0.00095 N/μm or more, or 0.00090 N/μm or more. It was possible to increase it to 00100N/μm or more. Thereby, the opening property of the bag 10 provided with the packaging material 30 could be improved.

Furthermore, as can be seen from the comparison between Example A2 and Comparative Examples A1 and A2, the inclusion of the high stiffness polyester film in the packaging material 30 suppresses the stretching of the sealant layer 70 when the packaging material 30 is torn. was completed. Moreover, as can be seen from Example A3, by using ZK500R as the sealant layer 70, the tearability of the packaging material 30 could be further improved. Regarding tearability, in Examples A1 and A2, the test piece 95 could be torn smoothly over the entire area in the direction of length V5, so the evaluation results were rated as "good." In addition, in Example A3, the test piece 95 can be torn smoothly over the entire area in the length V5 direction, and the position of the two packaging materials 30 constituting the test piece 95 in the width V4 direction can be easily torn. Since the amount of deviation was 5 mm or less, the evaluation result was rated "great." On the other hand, in Comparative Examples A1 and A2, the sealant layer 70 of the packaging material 30 stretched halfway, and therefore the test piece 95 could not be torn smoothly over the entire area in the direction of length V5. The result was rated as "bad".

Moreover, as can be seen from Example A1, by using ZK500 as the sealant layer 70, it was possible to suppress damage to the packaging material 30 of the bag 10 during heating. It is thought that the characteristic of ZK500 that the hot sealing strength is low contributes to the suppression of damage.

Next, examples and comparative examples regarding the case where the packaging material 210 has the barrier laminated film 205 described in the second embodiment will be described.

[Example B1]
As the base material 201, a high stiffness PET film made of petroleum-derived PET and having a loop stiffness of 0.0017N or more was prepared. Specifically, XP-55 manufactured by Toray Industries, Inc. was used as a high stiffness PET film. The thickness of the high stiffness PET film was 16 μm. Furthermore, the measured loop stiffness of the high stiffness PET film was 0.0021N in both the machine direction and the vertical direction. Further, the tensile modulus of the high stiffness PET film in the machine direction was 4.8 GPa, and the tensile modulus of the high stiffness polyester film in the vertical direction was 4.7 GPa.
Further, the tensile strength of the high stiffness PET film in the machine direction was 292 MPa, and the tensile strength of the high stiffness polyester film in the vertical direction was 257 MPa. Further, the tensile elongation of the high stiffness PET film in the machine direction was 107%, and the tensile elongation of the high stiffness polyester film in the vertical direction was 102%. In this case, the tensile strength of the high stiffness PET film in the machine direction divided by the tensile elongation is 2.73 [MPa/%], and the tensile strength of the high stiffness PET film in the vertical direction divided by the tensile elongation is 2.73 [MPa/%]. The value is 2.52 [MPa/%].
Further, the heat shrinkage rate of the high stiffness PET film in both the flow direction and the vertical direction was 0.4%.

Subsequently, the puncture strength of the high stiffness PET film was measured in accordance with JIS Z1707 7.4. As a measuring instrument, Tensilon universal material testing machine RTC-1310 manufactured by A&D was used. Specifically, a semicircular needle with a diameter of 1.0 mm and a tip shape radius of 0.5 mm was applied to a fixed high stiffness PET film test piece from the outer surface 30y side at 50 mm/min (1 The needle was stabbed at a speed of 50 mm per minute) and the maximum stress was measured until the needle penetrated the high stiffness PET film. The maximum value of stress was measured for five or more test pieces, and the average value was taken as the puncture strength of the high stiffness PET film. The environment during measurement was a temperature of 23° C. and a relative humidity of 50%. As a result, the puncture strength was 10.2N.

[Example B2]
As the base material 201, a PBT film prepared by a casting method and including a plurality of layers as described in the above-mentioned first configuration was prepared. The content of PBT in each layer was 80%, the number of layers was 1024, and the thickness of the PBT film was 15 μm. Further, the tensile strength of the PBT film in the machine direction was 191 MPa, and the tensile strength of the PBT film in the vertical direction was 289 MPa. Further, the tensile elongation of the PBT film in the machine direction was 195%, and the tensile elongation of the PBT film in the vertical direction was 100%. In this case, the tensile strength of the PBT film in the machine direction divided by the tensile elongation is 0.98 [MPa/%], and the tensile strength of the PBT film in the vertical direction divided by the tensile elongation is 2. It is 89 [MPa/%].
Further, the heat shrinkage rate of the PBT film in both the flow direction and the vertical direction was 0.4%.

[Example C1]
First, a vapor deposition layer 202 was formed on a base material 201, and a gas barrier coating film 203 was formed on the vapor deposition layer 202 to produce a barrier multilayer film 205. Subsequently, a packaging material 210 including the barrier laminate film 205 was produced.

First, the production of the barrier laminate film 205 will be explained. First, as the base material 201, a roll of the high stiffness PET film having a thickness of 16 μm used in the above-mentioned Example B1 was prepared. Subsequently, the base material 201 was subjected to oxygen plasma treatment using the above-described film forming apparatus 260 shown in FIG. 20, and then a 12 nm thick vapor deposition layer 202 containing aluminum oxide was formed on the oxygen plasma treated surface. . The oxygen plasma treatment and film formation treatment will be described in detail below.

In the oxygen plasma treatment, plasma is introduced from the plasma supply nozzle 272 under the following conditions in the plasma pretreatment chamber 262B to the surface of the base material 201 on which the vapor deposition layer 202 is provided, and the substrate is transported at a transport speed of 400 m/min. Material 201 was subjected to plasma pretreatment. As a result, an oxygen plasma treated surface was formed on the surface of the base material 201 on which the vapor deposition layer 202 was to be provided.
[Oxygen plasma pretreatment conditions]
・Plasma intensity: 200W・sec/m ²
・Plasma forming gas ratio: oxygen/argon = 2/1
・Voltage applied between pre-treatment drum and plasma supply nozzle: 340V
・Vacuum degree of pre-treatment section: 3.8 Pa

In the film forming process, in the film forming chamber 262C into which the base material 201 is continuously transported from the plasma pretreatment chamber 262B, aluminum is used as a target to deposit a thick film on the oxygen plasma treated surface of the base material 201. A vapor deposition layer 202 containing aluminum oxide with a thickness of 12 nm was formed on the base material 201 by a vacuum evaporation method. A reactive resistance heating method was adopted as a heating means for the vacuum evaporation method. The film forming conditions are as follows.
[Aluminum oxide film formation conditions]
・Vacuum degree: 8.1×10 ^-2 Pa
・Transportation speed: 400m/min
・Oxygen gas supply amount: 20000sccm

Subsequently, a gas barrier coating film 203 was formed on the vapor deposition layer 202. Specifically, first, 385 g of water, 67 g of isopropyl alcohol, and 9.1 g of 0.5N hydrochloric acid were mixed, and 175 g of tetraethoxysilane as a metal alkoxide and glycide as a silane coupling agent were added to a solution adjusted to pH 2.2. Solution A was prepared by mixing 9.2 g of oxypropyltrimethoxysilane while cooling to 10°C.
A solution B was prepared by mixing 14.7 g of polyvinyl alcohol with a polymerization degree of 2400 with a saponification value of 99% or higher, 324 g of water, and 17 g of isopropyl alcohol as a water-soluble polymer.
Subsequently, liquid A and liquid B were mixed at a weight ratio of 6.5:3.5. The solution thus obtained was used as a coating agent for a gas barrier coating film.

The above-mentioned vapor-deposited layer 202 was coated with the gas barrier coating agent prepared above by a spin coating method. Thereafter, heat treatment was performed in an oven at 180° C. for 60 seconds to form a gas barrier coating film 203 with a thickness of about 400 nm on the vapor deposited layer 202. In this way, a barrier laminate film 205 having a base material 201, a vapor deposited layer 202, and a gas barrier coating film 203 was obtained.

(metamorphism rate)
In a vacuumed environment, the surface of the gas barrier coating film 203 of the barrier multilayer film 205 is subjected to time-of-flight secondary ion mass spectrometry (TOF) while repeating soft etching at a constant rate with a Cs (cesium) ion gun. - SIMS), ions originating from the gas barrier coating film 203, ions originating from the vapor deposited layer 202, and ions originating from the base material 201 were measured. For example, mass spectrometry was performed on C ₆ (mass number 72.00) ions derived from the resin film of the base material 201 and Al ₂ O ₄ H (mass number 118.93) ions derived from the aluminum oxide vapor deposition film of the vapor deposition layer 202 .

The time-of-flight secondary ion mass spectrometer used in TOF-SIMS is ION TOF's TOF. Measurements were performed using SIMS5 under the following measurement conditions. As a result, a graph as shown in FIG. 19 was obtained.
(TOFSIMS measurement conditions)
・Primary ion type: Bi ₃ ++ (0.2pA, 100μs)
・Measurement area: 150 x 150 μm ²
・Etching gun type: Cs (1keV, 60nA)
・Etching area: 600 x 600 μm ²
・Etching rate: 3sec/cycle
- Evacuation time: 15 hours or more at 1×10 ⁻⁶ mbar or less Measurements using a time-of-flight secondary ion mass spectrometer were performed within 30 hours after evacuation was started.

In the graph, the position where the strength of SiO ₂ (mass number 59.96), which is a constituent element of the gas barrier coating film 203, is half the strength of the gas barrier coating film 203 is defined as the position between the gas barrier coating film 203 and the vapor deposition layer 202. It was identified as an interface. Further, a position where the strength of C ₆ (mass number 72.00), which is a constituent material of the base material 201, is half of the strength in the base material 201 was specified as the interface between the base material 201 and the vapor deposited layer 202. Further, the distance between the two interfaces in the thickness direction was adopted as the thickness of the vapor deposited layer 202.

Next, a peak representing the measured elemental bond Al ₂ O ₄ H (mass number 118.93) was determined, and the region from the peak to the interface was defined as a transition region. However, if the gas barrier coating film 203 is composed of a material having the same mass number as Al ₂ O ₄ H (mass number 118.93), it is necessary to separate the waveform of 118.93.

When the reactant AlSiO ₄ and the hydroxide Al ₂ O ₄ H are generated at the interface between the gas barrier coating film 203 and the vapor deposited layer 202, they and the Al present at the interface between the base material 201 and the vapor deposited layer 202. ₂ O ₄ H can be separated. In this way, waveform separation can be handled appropriately depending on the material of the gas barrier coating film 203.

In waveform separation, for example, a profile with a mass number of 118.93 obtained by TOF-SIMS is subjected to nonlinear curve fitting using a Gaussian function, and overlapping peaks are separated using a least squares method Levenberg Marquardt algorithm. You may go.

Two samples were prepared from the barrier laminated film 205 of Example C1, and for each of the two samples, the metamorphosis rate of the vapor deposited layer 202 was determined as follows: (thickness of transition region W ₁ /thickness of vapor deposited layer 202) x 100 (%) ). As a result, the metamorphism rate in the first sample was 36.2%, and the metamorphosis rate in the second sample was 28.8%.

Next, the production of the packaging material 210 including the barrier laminated film 205 will be described. First, a printing layer 218 having a thickness of 1 μm was formed on the gas barrier coating film 203 of the barrier laminate film 205. Further, the film containing the barrier laminate film 205 and the film constituting the sealant layer 212 were bonded together by a dry lamination method via the first adhesive layer 213 having a thickness of 3.5 μm. As the film for the sealant layer 212, an unstretched polypropylene film (thickness: 60 μm) was used. As the unstretched polypropylene film, unstretched polypropylene film ZK207 manufactured by Toray Film Kako Co., Ltd. was used. In this way, a packaging material 210 having the layer structure shown in FIG. 16 was produced. The overall thickness of the packaging material 210 was 80.5 μm.

The layer structure of the packaging material 210 of this example is expressed as follows.
High PET16/Transparent vapor deposition/Barrier/Mark/Adhesive/CPP60
"High PET" means high stiffness PET film. "Transparently deposited" means a transparently deposited layer containing aluminum oxide. "Barrier" means a gas barrier coating film. "Mark" means a printed layer. "Adhesive" means an adhesive layer. "CPP" means unoriented polypropylene film. The numbers refer to the layer thickness (in μm).

Subsequently, the puncture strength and loop stiffness of the packaging material 210 were measured in the same manner as in Example A1. As a result, the puncture strength was 13.2N. The loop stiffness of the packaging material 210 in the machine direction was 0.084N, and the loop stiffness in the vertical direction was 0.079N. In this case, the loop stiffness in the flow direction of the packaging material 210 divided by the thickness of the packaging material 210 is 0.00104N/μm, and the loop stiffness in the vertical direction divided by the thickness of the packaging material 210 is 0.00098N. /μm.

Further, as described below, after the packaging material 210 of Example C1 was subjected to retort treatment, oxygen permeability and water vapor permeability were measured.

(Oxygen permeability)
A four-sided sealed pouch was produced using packaging material 210. Subsequently, 100 mL of water was injected into the four-side sealed pouch from the opening at the top of the four-sided sealed pouch, and then a seal portion was formed at the top to seal the four-sided sealed pouch. Subsequently, the four-sided sealed pouch was subjected to retort treatment at 121°C for 40 minutes at 2 atm.
Subsequently, the packaging material 210 constituting one side of the four-sided sealed pouch after the retort treatment was cut out to prepare a sample for evaluating the oxygen permeability after the retort treatment.

Next, the sample after retort treatment was set so that the base material 201 was on the oxygen supply side, and the oxygen permeability was measured in accordance with JIS K 7126 B method under measurement conditions of 23°C and 100% RH atmosphere. was measured. As a measuring device, an oxygen permeability measuring device (manufactured by Modern Control (MOCON) [model name: OX-TRAN 2/21]) was used. As a result, the oxygen permeability of the sample after retort treatment was less than 1.5cc/m ² /24hr/atm.

(water vapor permeability)
Water vapor permeability was measured using the same sample as in the case of oxygen permeability measurement. Specifically, each sample was set with the base material 201 facing the sensor side, and the water vapor permeability was measured in accordance with JIS K 7126 B method under measurement conditions of 37.8°C and 100% RH atmosphere. was measured. As a measuring device, a water vapor permeability measuring device (a measuring device manufactured by MOCON [model name: PERMATRAN 3/33]) was used. As a result, the water vapor permeability of the sample after retort treatment was less than 2.0 g/m ² /24 hr.

The packaging material 210 of this example can be used, for example, to construct a pouch that is subjected to retort processing.

[ Reference example C2]
A barrier laminate film 205 was produced in the same manner as in Example C1. Next, as in Example C1, except that a sealant film (thickness: 50 μm) made of a mixed resin of low-density polyethylene and linear low-density polyethylene was used as the film of the sealant layer 212, FIG. A packaging material 210 having the layer structure shown in No. 16 was produced. The overall thickness of the packaging material 210 was 70.5 μm.

The layer structure of the packaging material 210 of this example is expressed as follows.
High PET16/Transparent vapor deposition/Barrier/Mark/Adhesive/Blend PE50
"Blend PE" means a sealant film made of a mixed resin of low-density polyethylene and linear low-density polyethylene.

Subsequently, the puncture strength and loop stiffness of the packaging material 210 were measured in the same manner as in Example A1. As a result, the puncture strength was 12.5N. The loop stiffness of the packaging material 210 in the machine direction was 0.051N, and the loop stiffness in the vertical direction was 0.053N. In this case, the value obtained by dividing the loop stiffness in the flow direction of the packaging material 210 by the thickness of the packaging material 210 is 0.00072 N/μm, and the value obtained by dividing the loop stiffness in the vertical direction by the thickness of the packaging material 210 is 0.00075 N. /μm.

Further, as described below, after the packaging material 210 of Example B2 was subjected to boiling treatment, oxygen permeability and water vapor permeability were measured.

(Oxygen permeability)
A four-sided sealed pouch was produced using packaging material 210. Subsequently, 100 mL of water was injected into the four-side sealed pouch from the opening at the top of the four-sided sealed pouch, and then a seal portion was formed at the top to seal the four-sided sealed pouch. Subsequently, the four-sided sealed pouch was subjected to a boiling process at 95° C. for 60 minutes.
Subsequently, the packaging material 210 constituting one side of the four-sided sealed pouch after being subjected to the boiling process was cut out to prepare a sample for evaluating the oxygen permeability after the boiling process. Subsequently, the oxygen permeability of the sample after the boiling treatment was measured in the same manner as in Example C1. As a result, the oxygen permeability was less than 1.5cc/m ² /24hr/atm.

(water vapor permeability)
Using the same sample as in the measurement of oxygen permeability, the water vapor permeability of the sample after boiling treatment was measured in the same manner as in Example C1. As a result, the water vapor permeability was less than 2.0g/m ² /24hr.

The packaging material 210 of this example can be used, for example, to construct a pouch that is subjected to a boiling process.

[ Reference example C3]
A barrier laminate film 205 was produced in the same manner as in Example C1. Next, as the film of the sealant layer 212, a sealant film (thickness: 50 μm) with easy-peel properties, which was formed by co-extrusion and included the first layer 2121 and second layer 2122 shown in FIG. 17, was used. A packaging material 210 having the layer structure shown in FIG. 17 was produced in the same manner as in Example C1. The first layer 2121 is a 5 μm thick layer made of a mixed resin of high density polyethylene and polypropylene. The second layer 2122 is a 45 μm thick layer made of high density polyethylene. The overall thickness of the packaging material 210 was 70.5 μm.

The layer structure of the packaging material 210 of this example is expressed as follows.
High PET16/Transparent vapor deposition/Barrier/Mark/Adhesive/Easy Peel 50
"Easy peel" refers to a sealant film that includes a layer made of a mixed resin of polyethylene and polypropylene and has easy peel properties.

Subsequently, the puncture strength and loop stiffness of the packaging material 210 were measured in the same manner as in Example A1. As a result, the puncture strength was 12.4N. The loop stiffness of the packaging material 210 in the machine direction was 0.054N, and the loop stiffness in the vertical direction was 0.054N. In this case, the value obtained by dividing the loop stiffness in the flow direction of the packaging material 210 by the thickness of the packaging material 210 is 0.00077N/μm, and the value obtained by dividing the loop stiffness in the vertical direction by the thickness of the packaging material 210 is 0.00077N. /μm.

Subsequently, as in Example C1, a four-sided sealed pouch made using packaging material 210 was subjected to retort treatment, and then oxygen permeability was measured using a sample cut from the four-sided sealed pouch, and water vapor permeation was measured. The temperature was measured. As a result, the oxygen permeability of the sample after retort treatment was less than 1.5cc/m ² /24hr/atm. Furthermore, the water vapor permeability of the sample after retort treatment was less than 2.0 g/m ² /24 hr.

The packaging material 210 of this embodiment can be used, for example, to constitute a lidding material for a lidded container to be subjected to retort processing. The container body of the lidded container may be made of polypropylene, for example.

The layer structure of the packaging material 210 of Example C1 and Reference Examples C2 to C3, and the evaluation results regarding puncture strength and loop stiffness are summarized in FIG. 28. Further, FIG. 29 shows the layer structure of the packaging material 210 of Example C1 and Reference Examples C2 to C3, as well as the evaluation results of oxygen permeability and water vapor permeability. In the "Oxygen Permeability" column of FIG. 29, "OK" means that the oxygen permeability of the sample after retort treatment was less than 1.5 cc/m ² /24 hr/atm. Furthermore, in the column of "water vapor permeability" in FIG. 29, "OK" means that the water vapor permeability of the sample after retort treatment was less than 2.0 g/m ² /24 hr.

As can be seen from Example C1 and Reference Examples C2 and C3, by using a high stiffness polyester film as the stretched plastic film 60, the packaging material 30 can be Even when only one stretched plastic film was included, the puncture strength of the packaging material 30 could be increased to 12N or more, for example, 13N or more. Further, in Example C1 in which unstretched polypropylene film ZK207 manufactured by Toray Film Kako Co., Ltd. was used as the sealant layer 70, the value obtained by dividing the loop stiffness of the packaging material 30 by the thickness of the packaging material 30 in at least one direction was It was possible to increase the resistance to 0.00085 N/μm or more, specifically to 0.00095 N/μm or more or 0.00100 N/μm or more.

10 bags (pouch)
11 Upper part 12 Lower part 12a Lower seal part 13 Side part 13a Side seal part 14 Front film 15 Back film 16 Lower film 17 Storage part 18 Contents 20 Steam release mechanism 20a Steam release seal part 25 Easy-opening means 26 Notch 30 Packaging material 35 Base material 60 Stretched plastic film 65 Adhesive layer 70 Sealant layer 80 Test piece 80A Flow direction test piece 80B Vertical direction test piece 80x Inner surface 80y Outer surface 81 Loop portion 82 Intermediate portion 83 Fixed portion 85 Loop stiffness measuring device 86 Chuck portion 861 First chuck 862 Second chuck 87 Support member 88 Load cell 201 Base material 202 Vapor deposited layer 203 Gas barrier coating film 205 Barrier laminated film 210 Packaging material 212 Sealant layer 2121 First layer 2122 Second layer 213 First adhesive layer 218 Printing layer

Claims (10)

A packaging material,
Comprising a base material and a sealant layer,
The base material has only one biaxially oriented plastic film containing polyester as a main component,
The sealant layer contains polypropylene as a main component,
The value obtained by dividing the loop stiffness in one direction of the packaging material by the thickness of the packaging material is 0.00085 [N/μm] or more,
the biaxially oriented plastic film is located on the outer surface of the packaging material;
The packaging material includes only the biaxially stretched plastic film as the stretched plastic film. The packaging material according to claim 1, wherein the biaxially oriented plastic film has a loop stiffness of 0.0017N or more in one direction. The packaging material according to claim 1 or 2, wherein the biaxially stretched plastic film has a tensile strength divided by tensile elongation of 2.0 [MPa/%] or more in at least one direction. The packaging material according to any one of claims 1 to 3, wherein the biaxially stretched plastic film contains polyethylene terephthalate as a main component. The packaging material according to any one of claims 1 to 4, wherein the packaging material has a puncture strength of 12N or more. Packaging material according to any one of claims 1 to 5, comprising a printed layer. The packaging material according to any one of claims 1 to 6, comprising a vapor deposition layer located on the surface of the biaxially stretched plastic film and a gas barrier coating film located on the vapor deposition layer. The packaging material according to any one of claims 1 to 7, wherein the sealant layer is a single layer film containing a propylene/ethylene block copolymer. A retort pouch comprising the packaging material according to any one of claims 1 to 8 . A microwave pouch having a housing part,
The packaging material according to any one of claims 1 to 8 ,
A pouch for a microwave oven, comprising: a seal section that joins the inner surfaces of the packaging material together, and includes a steam release seal section that peels off due to an increase in pressure in the storage section.

Images