JP2020055633A - Packaging material and bag including packaging material - Google Patents

Abstract

To provide a packaging material having a tearing property.SOLUTION: A packaging material includes a base material and a sealant film; the base material includes at least one oriented plastic film containing polyester or polyamide as a main component; the sealant film contains a propylene-ethylene block copolymer; a product of a tensile modulus (MPa) of the sealant film in a flowing direction and a thickness (μm) of the sealant film is 35000 or more.SELECTED DRAWING: Figure 2

Description

  The present invention relates to a packaging material and a bag provided with the packaging material.

  BACKGROUND ART Conventionally, various packaging materials have been developed and proposed as packaging materials for forming bags for filling and packaging various articles such as foods and drinks, pharmaceuticals, chemicals, cosmetics, sanitary products, daily necessities, and the like. The packaging material is composed of a laminate in which at least one stretched plastic film and a sealant film for welding the packaging materials to each other are at least laminated. For example, Patent Document 1 discloses that as a packaging material, a stretched polyethylene terephthalate film, a silica-deposited stretched polyethylene terephthalate film, an alumina-deposited stretched polyethylene terephthalate film, a stretched nylon film, a stretched polypropylene film, or a polypropylene / ethylene-vinyl alcohol copolymer. It has been proposed to use a stretched film or a composite film obtained by laminating two or more of these films.

JP 2015-120550 A

  When removing the contents from the container, the consumer breaks the bag and opens it. Considering the convenience of consumers, it is preferable that the packaging material of the bag is configured so that the bag can be opened by tearing the bag by hand or the like.

  The present invention has been made in view of such a point, and an object of the present invention is to provide a packaging material having tearability.

  The present invention is a packaging material, comprising a substrate and a sealant film, wherein the substrate has at least one stretched plastic film containing polyester or polyamide as a main component, and the sealant film is a propylene / ethylene block. A packaging material comprising a copolymer, wherein a product of a tensile modulus (MPa) of the sealant film in the flow direction and a thickness (μm) of the sealant film is 35,000 or more.

  In the packaging material according to the present invention, the product of the tensile elastic modulus (MPa) of the sealant film in the flow direction and the thickness (μm) of the sealant film may be 42,000 or more.

  In the packaging material according to the present invention, the base material includes a first stretched plastic film, a second stretched plastic film located between the first stretched plastic film and the sealant film, and One of the plastic film and the second stretched plastic film may contain polyester as a main component, and the other of the first stretched plastic film or the second stretched plastic film may contain polyester or polyamide as a main component. In this case, one of the first stretched plastic film and the second stretched plastic film may be a high stiffness polyester film containing polyester as a main component and having a loop stiffness of 0.0017 N or more in one direction. The value obtained by dividing the tensile strength of the high stiffness polyester film by the tensile elongation in at least one direction may be 2.0 [MPa /%] or more. The piercing strength of the packaging material is preferably 14 N or more. The loop stiffness in one direction of the packaging material is preferably greater than or equal to 0.160N. The value obtained by dividing the loop stiffness in one direction of the packaging material by the thickness of the packaging material is preferably 0.00150 [N / μm] or more.

  In the packaging material according to the present invention, the substrate may have only one of the stretched plastic films. In this case, the stretched plastic film may be a high stiffness polyester film containing polyester as a main component and having a loop stiffness of 0.0017 N or more. The value obtained by dividing the tensile strength of the high stiffness polyester film by the tensile elongation in at least one direction may be 2.0 [MPa /%] or more. The value obtained by dividing the loop stiffness in one direction of the packaging material by the thickness of the packaging material is preferably 0.00085 [N / μm] or more.

  The present invention is a bag provided with the packaging material described above.

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

It is a front view showing a bag in an embodiment of the invention. It is a sectional view showing an example of layer composition of a packaging material of a 1st embodiment. It is a top 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. 3 taken along line VV. It is a figure for explaining a process of attaching a test piece to a loop stiffness measuring instrument. 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 a loop part of a test piece. It is a figure for explaining the process of applying a load to a loop part of a test piece. It is sectional drawing which shows a modification of the layer structure of the packaging material of 1st Embodiment. It is sectional drawing which shows a modification of the layer structure of the packaging material of 1st Embodiment. It is sectional drawing which shows an example of the layer structure of the packaging material of 2nd Embodiment. It is sectional drawing which shows one modification of the layer structure of the packaging material of 2nd Embodiment. It is a front view showing a modification of a bag. It is a front view showing a modification of a bag. It is a longitudinal section showing an example of a container containing packaging material. It is a top view which shows an example of the container containing a packaging material. It is a figure which shows an example of the measuring method of piercing strength. It is a top view which shows the test piece for evaluating a tearability. It is a figure which shows the evaluation result of Examples A1-A3 and Comparative Example A1. It is a figure which shows the evaluation result of Examples A1-A3 and Comparative Example A1. It is a figure which shows the evaluation result of Example B1 and Comparative Examples B1 and B2. It is a figure which shows the evaluation result of Example B1 and Comparative Examples B1 and B2.

First Embodiment A first embodiment of the present invention will be described with reference to FIGS. In the drawings attached to the present specification, the scale, the vertical and horizontal dimensional ratios, and the like are appropriately changed from those of the actual product and exaggerated for convenience of illustration and understanding.

  In addition, in this specification, to specify the shape and geometric conditions and the degree thereof, for example, such as "parallel", "orthogonal", "identical" and the like, and the value of the length and angle, etc., strict Without being constrained by the meaning, it should be interpreted to include a range in which a similar function can be expected.

  FIG. 1 is a front view showing a bag 10 according to the present embodiment. The bag 10 includes a storage unit 17 that stores contents. Note that FIG. 1 shows the bag 10 in a state before the contents are stored. Hereinafter, the configuration of the bag 10 will be described.

In the present 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 substantially rectangular outline in a front view. Note that names such as “upper”, “lower” and “side”, and terms such as “upper” and “lower” refer to a state in which the bag 10 It is merely a relative representation of the position and orientation of 10 and its components. The posture at the time of transporting or using the bag 10 is not limited by the names and terms in this specification.

  In the present embodiment, the width direction of the bag 10 is also referred to as a first direction D1. The above-mentioned pair of side parts 13 are opposed in the first direction D1. Further, a direction orthogonal to the first direction D1 is also referred to as a second direction D2. In the bag 10 according to the present embodiment, a usage pattern in which the consumer opens the bag 10 by tearing the bag 10 along the first direction D1 is assumed.

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

  In addition, the above-mentioned terms "front film", "back film", and "lower film" are only those in which each film is partitioned according to the positional relationship, and the method of providing the film when manufacturing the bag 10, It is not 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 continuously provided, and one sheet in which the front film 14 and the lower film 16 are continuously provided. It may be manufactured using a total of two films, one film and one back film 15, and a total of three films, one front film 14, one back film 15, and one lower 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 the plan view of the bag 10 such as FIG. 1, hatching is applied to the seal portion.

  As shown in FIG. 1, the seal portion has an outer edge seal portion extending along the outer edge of the bag 10. 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 the bag 10 before the contents are stored, the upper portion 11 of the bag 10 is an opening 11b, as shown in FIG. 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 portion 11, thereby forming an upper seal portion and sealing the bag 10.

  The side seal portion 13a and the upper seal portion 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 portion 12a is formed by bonding the inner surface of the front film 14 and the inner surface of the lower film 16, and the lower seal portion 12a by bonding the inner surface of the back film 15 and the inner surface of the lower film 16. Includes a configured seal.

  The method for forming the seal portion is not particularly limited as long as the bag 10 can be sealed by joining the opposing films. For example, the sealing portion may be formed by melting the inner surfaces of the film by heating or the like and welding the inner surfaces to each other, that is, by heat sealing. Alternatively, the seal portion may be formed by bonding the inner surfaces of the opposing films using an adhesive or the like.

Easy Opening Means The front film 14 and the back film 15 may be provided with an easy opening means 25 for tearing the front film 14 and the back film 15 along the first direction D1 and opening the bag 10. . For example, as shown in FIG. 1, the easy-opening means 25 may include a notch 26 formed on the side seal portion 13 a of the bag 10 and serving as a starting point of a tear. In addition, a half-cut line formed by laser processing, a cutter, or the like may be provided as an easy-opening means 25 in a portion serving as a path when the bag 10 is torn.

  Although not shown, the easy-opening means 25 may include a cut or a group of scars formed in a 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 Configuration of Front Film and Back Film Next, the layer configuration of the front film 14 and the back film 15 will be described. FIG. 2 is a cross-sectional view illustrating an example of a layer configuration of the packaging material 30 that forms 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 film 70. The substrate 35 has at least one stretched plastic film. In the example shown in FIG. 2, the base 35 has a first stretched plastic film 40 and a second stretched plastic film 50 located between the first stretched plastic film 40 and the sealant film 70. Further, the packaging material 30 includes an adhesive layer for bonding the films. Therefore, the packaging material 30 shown in FIG. 2 includes at least the first stretched plastic film 40, the first adhesive layer 45, the second stretched plastic film 50, the second adhesive layer 55, and the sealant film 70 in this order. The first stretched plastic film 40 is located on the outer surface 30y side, and the sealant film 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 accommodation unit 17 side.

  The packaging material 30 of the present embodiment is configured to have tearability. Thereby, the tearing property when the consumer opens the bag 10 can be improved. Also, preferably, the packaging material 30 of the present embodiment is configured to have rigidity. Accordingly, the bag 10 including the packaging material 30 can have rigidity. For example, it is possible to prevent the bag 10 from being broken when a sharp member having a sharp tip contacts the bag 10. The thickness of the packaging material 30 is, for example, 80 μm or more, 90 μm or more, 100 μm or more, or 105 μm or more. The thickness of the packaging material 30 may be 140 μm or less, 130 μm or less, 120 μm or less, 115 μm or less, or 110 μm or less.

  Hereinafter, each layer of the packaging material 30 will be described in detail.

(Stretched plastic film)
Each of the first stretched plastic film 40 and the second stretched plastic film 50 is a plastic film stretched in a predetermined direction. Each of the stretched plastic films 40 and 50 may be a uniaxially stretched film stretched in one predetermined direction or a biaxially stretched film stretched in two predetermined directions. The stretching direction of each stretched plastic film 40, 50 is not particularly limited. For example, the stretched plastic films 40 and 50 may be stretched in a direction in which the side portions 13 extend, or may be stretched in a direction orthogonal to the direction in which the side portions 13 extend. The stretching directions of the stretched plastic films 40 and 50 may be the same or different. The stretch ratio of each stretched plastic film 40, 50 is, for example, 1.05 times or more.

In the present embodiment, as one of the first stretched plastic film 40 and the second stretched plastic film 50, 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 We propose to use In the following description, a stretched plastic film having a loop stiffness of at least 0.0017 N 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) and the vertical direction (TD). The 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 in the packaging material 30, the packaging material 30 can have rigidity.
As the polyester, at least one aromatic dicarboxylic acid selected from terephthalic acid, isophthalic acid and 2,6-naphthalenedicarboxylic acid, and at least one selected from ethylene glycol, 1,3-propanediol and 1,4-butanediol A polyester mainly composed of an aromatic polyester composed of one kind of aliphatic alcohol is preferred. For example, polyester includes polyethylene terephthalate (hereinafter, also referred to as PET), polybutylene terephthalate (hereinafter, also referred to as PBT), and the like. Examples of the high stiffness polyester film include a high stiffness PET film containing 51% by mass or more of PET as a main component, and a high stiffness PBT film containing 51% by mass or more of PBT as a main component. 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.

  The loop stiffness is a parameter indicating the strength of the film. Hereinafter, a method for measuring loop stiffness will be described with reference to FIGS. The measurement method described below can be used not only for a single-layer film such as a stretched plastic film but also for a film having a plurality of layers such as a vapor-deposited film and a laminated film. The vapor-deposited film is a film including a single-layer film such as a stretched plastic film and a vapor-deposited layer formed on the single-layer film. The laminated film is a film including a plurality of laminated films, such as the packaging material 30.

  FIG. 3 is a plan view showing the test piece 80 and the loop stiffness measuring device 85, and FIG. 4 is a cross-sectional view of the test piece 80 and the loop stiffness measuring device 85 of FIG. 3 along line V-V. The test piece 80 is a rectangular film having a long side and a short side. In the present application, the length L1 of the long side of the test piece 80 is 150 mm, and the length L2 of the short side is 15 mm. As the loop stiffness measuring device 85, for example, No. A 581 Loop Stefness Tester (registered trademark) LOOP STIFFNESS TESTER DA type can be used. 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 portions 86 described later.

  The loop stiffness measuring device 85 has a pair of chucks 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 chucks 86. The chuck unit 86 includes a first chuck 861 and a second chuck 862. In the state shown in FIGS. 3 and 4, the test piece 80 is disposed on the pair of first chucks 861, and the second chuck 862 still holds the test piece 80 with the first chuck 861. Not. As described later, at the time of measurement, the test piece 80 is held between the first chuck 861 and the second chuck 862 of the chuck unit 86. The second chuck 862 may be connected to the first chuck 861 via a hinge mechanism.

  When a film to be measured, such as a stretched plastic film, a vapor-deposited film, or a laminated film, is available in a state before the film is processed into a packaged product, the test piece 80 is manufactured by cutting the film to be measured. You may. In addition, the test piece 80 may be manufactured by cutting a packaged product manufactured from the packaging material 30 such as a bag and taking out a film to be measured.

  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. 3 and 4, the test piece 80 is placed on the first chuck 861 of the pair of chuck portions 86 arranged with an interval L3. In the present application, the interval L3 is set such that a length of a loop portion 81 described below (hereinafter, also referred to as a loop length) 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 match the inner surface 30x and the outer surface 30y of the packaging material 30. Subsequently, as shown in FIG. 5, the second chuck 862 is arranged on the test piece 80 so as to hold the end of the test piece 80 in the long side direction between the first chuck 861 and the first chuck 861.

  Subsequently, as shown in FIG. 6, at least one of the pair of chuck portions 86 is slid on the support member 87 in a direction in which the interval between the pair of chuck portions 86 is reduced. Thereby, the loop portion 81 can be formed on the test piece 80. The test piece 80 shown in FIG. 6 has a loop portion 81, a pair of intermediate portions 82, and a pair of fixing portions 83. The pair of fixing portions 83 are portions of the test piece 80 that are gripped by the pair of chuck portions 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. 6, the chuck portion 86 is slid on the support member 87 until the inner surfaces 80x of the pair of intermediate portions 82 contact 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 determined by the position P1 where the surface of the one second chuck 862 on the loop portion 81 side and the test piece 80 intersect, and the loop length of the other second chuck 862 on the loop portion 81 side and the test piece 80. Is the length of the test piece 80 between the position P2 and the intersection of 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 section 86.

  Thereafter, as shown in FIG. 7, the posture of the chuck portion 86 is adjusted such that the projecting direction Y of the loop portion 81 with respect to the chuck portion 86 is horizontal. For example, the posture of the chuck unit 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 is horizontal. In the example shown in FIG. 7, the projecting direction Y of the loop portion 81 matches the thickness direction of the chuck portion. Further, the load cell 88 is prepared at a position away from the second chuck 862 by the distance Z1 in the projecting direction Y of the loop portion 81. In the present application, the distance Z1 is set to 50 mm. Subsequently, the load cell 88 is moved toward the loop portion 81 of the test piece 80 at the speed V by the distance Z2 shown in FIG. 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. In the present application, the distance Z2 is set to 40 mm. In this case, the distance Z3 between the load cell 88 and the second chuck 862 of the chuck unit 86 when the load cell 88 is pushing the loop unit 81 toward the chuck unit 86 is 10 mm. The speed V at which the load cell 88 was moved was 3.3 mm / sec.

  Subsequently, as shown in FIG. 8, the load cell 88 is moved toward the chuck portion 86 by the distance Z2 and is added to the load cell 88 from the loop portion 81 in a state where the load cell 88 is pushing the loop portion 81 of the test piece 80. After the load value stabilizes, record the load value. The value of the load thus obtained is adopted as the loop stiffness of the film constituting the test piece 80. In the present application, unless otherwise specified, the environment when measuring the loop stiffness is a temperature of 23 ° C. and a relative humidity of 50%.

Preferred mechanical properties of the high stiffness polyester film will be further described.
The piercing strength of the high stiffness polyester film is preferably 10 N or more, more preferably 11 N 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 flow 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 flow direction is preferably 130% or less, more preferably 120% or less. 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 in at least one direction is 2.0 [MPa /%] or more. For example, the value obtained by dividing the tensile strength of the high stiffness polyester film in the vertical direction (TD) by the tensile elongation is preferably 2.0 [MPa /%] or more, and more preferably 2.2 [MPa /%]. That is 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. is there.
The tensile strength and the tensile elongation can be measured according to JIS K7127. As a measuring device, a tensile tester STA-1150 manufactured by Orientec can be used. As the test piece, a high stiffness polyester film cut into a rectangular film having a width of 15 mm and a length of 150 mm can be used. The interval at the start of the measurement between the pair of chucks holding the test piece is 100 mm, and the tensile speed is 300 mm / min. The environmental temperature during the test is 25 ° C. In the present application, unless otherwise specified, the environment when measuring the tensile strength and the tensile elongation is a temperature of 23 ° C. and a relative humidity of 50%.
In the bag 10 shown in FIG. 1, the first direction D1 corresponds to the flow direction (MD) of the film such as the stretched plastic films 40, 50, 60. The second direction D2 corresponds to a vertical direction (TD) of a film such as the stretched plastic films 40, 50, 60.

The heat shrinkage 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 of the high stiffness polyester film in the flow direction is preferably 0.7% or less, more preferably 0.5% or less. The heat shrinkage 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 heat shrinkage is 100 ° C., and the heating time is 40 minutes.
The Young's modulus of the high stiffness polyester film in at least one direction is preferably 4.0 GPa or more, more preferably 4.5 MPa or more. For example, the Young's modulus of the high stiffness polyester film in the flow direction is preferably 4.0 GPa or more, more preferably 4.5 MPa or more. The Young's modulus of the high stiffness polyester film in the vertical direction is preferably 4.0 GPa or more, and more preferably 4.5 GPa or more.

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

  According to the present embodiment, since the packaging material 30 includes the high stiffness polyester film, the loop stiffness of the packaging material 30 can be increased as compared with the case where the packaging material 30 does not include the high stiffness polyester film. In particular, when the sealant film 70 contains polypropylene as a main component and the thickness of the packaging material 30 is 100 μm or more, the loop stiffness of the packaging material 30 can be increased. The loop stiffness of the packaging material 30 in at least one direction may be, for example, 0.160 N or more, 0.165 N or more, 0.170 N or more, or 0.175 N or more. , 0.180 N or more. For example, the loop stiffness of the packaging material 30 in the flow direction (MD) is, for example, 0.160 N or more, 0.165 N or more, 0.170 N or more, or 0.175 N or more. And may be 0.180 N or more. Further, the loop stiffness of the packaging material 30 in the vertical direction (TD) is, for example, 0.160 N or more, may be 0.165 N or more, may be 0.170 N or more, and may be 0.175 N or more. And may be 0.180 N or more.

  Further, according to the present embodiment, since the packaging material 30 includes the high stiffness polyester film, the loop stiffness of the packaging material 30 per unit thickness of the packaging material 30 can be increased. In particular, when the sealant film 70 contains polypropylene as a main component and the thickness of the packaging material 30 is 100 μm or more, 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, 0.00150 N / μm or more, may be 0.00155 N / μm or more, or 0.00160 N / μm. Or more, may be 0.00165 N / μm or more, or may be 0.00170 N / μm or more. For example, the value obtained by dividing the loop stiffness of the packaging material 30 in the flow direction (MD) by the thickness of the packaging material 30 is, for example, 0.00150 N / μm or more, and may be 0.00155 N / μm or more. It may be at least 1600 N / μm, at least 0.00165 N / μm, or at least 0.00170 N / μm. 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, 0.00150 N / μm or more, and may be 0.00155 N / μm or more. It may be at least 1600 N / μm, at least 0.00165 N / μm, or at least 0.00170 N / μm.

  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 biomass-derived PET. In this case, the high stiffness PET film may be composed of only biomass-derived PET. Alternatively, the high stiffness PET film may be composed of PET derived from biomass and PET derived from fossil fuel. Since the high stiffness PET film contains biomass-derived PET, the amount of fossil fuel-derived PET can be reduced as compared with the conventional case, so the amount of carbon dioxide emissions can be reduced and the environmental burden can be reduced. it can. In addition, PET derived from biomass is obtained by using ethylene glycol derived from biomass as a diol unit and terephthalic acid derived from fossil fuel as a dicarboxylic acid unit. PET derived from fossil fuel has ethylene glycol derived from fossil fuel as a diol unit and terephthalic acid derived from fossil fuel as a dicarboxylic acid unit.

  Since carbon dioxide in the atmosphere contains C14 at a fixed rate (105.5 pMC), the C14 content in plants that grow by taking in carbon dioxide in the atmosphere, for example, corn, is also about 105.5 pMC. It is known. It is also known that C14 is hardly contained in fossil fuels. Therefore, by measuring the ratio of C14 contained in all carbon atoms in PET, the ratio of carbon derived from biomass can be calculated. In the present invention, the “degree of biomass” indicates a weight ratio of a biomass-derived component. Taking PET as an example, PET is obtained by polymerizing ethylene glycol containing 2 carbon atoms and terephthalic acid containing 8 carbon atoms in a molar ratio of 1: 1. In the case where only ethylene glycol derived from PET is used as PET ethylene glycol, the weight ratio of the biomass-derived component in PET is 31.25%, and the theoretical value of the degree of PET biomass is 31.25%. Specifically, since the mass of PET is 192, and the mass derived from ethylene glycol derived from biomass is 60, 60 ÷ 192 × 100 = 31.25. In addition, the weight ratio of the biomass-derived component in PET derived from fossil fuel is 0%, and the biomass degree of PET derived from fossil fuel 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. The biomass degree of the high stiffness PET film is preferably 30.0% or less.

  Ethylene glycol derived from biomass is derived from ethanol produced from biomass (biomass ethanol). For example, biomass-derived ethylene glycol can be obtained from biomass ethanol by a conventionally known method, for example, by producing ethylene glycol via ethylene oxide. Corn, sugar cane, beet, manioc, etc. can be mentioned as a raw material of biomass ethanol. Further, commercially available biomass ethylene glycol may be used. For example, biomass ethylene glycol commercially available from Indiaglycol Co., Ltd. can be suitably used. In addition, the biomass ethylene glycol of Indiaglycol Co. is made from molasses of sugarcane.

  When one of the first stretched plastic film 40 and the second stretched plastic film 50 is a high stiffness polyester film, the other of the first stretched plastic film 40 and the second stretched plastic film 50 contains polyester or polyamide as a main component. For example, when the first stretched plastic film 40 is a high stiffness polyester film, the second stretched plastic film 50 may be a stretched plastic film containing 51% by mass or more of polyester or polyamide as a main component. When the second stretched plastic film 50 is a high stiffness polyester film, the first stretched plastic film 40 may be a stretched plastic film containing 51% by mass or more of polyester or polyamide as a main component. Also, both the first stretched plastic film 40 and the second stretched plastic film 50 may be high stiffness polyester films.

  When the bag 10 made of the packaging material 30 is subjected to a high-temperature sterilization treatment such as a boil treatment or a retort treatment, the stretched plastic forming the other of the first stretched plastic film 40 or the second stretched plastic film 50 is used. It is preferable that the film contains polyester as a main component.

  A stretched plastic film containing polyester as a main component (hereinafter also referred to as a stretched polyester film) contains, for example, 51% by mass or more of polyester. As the polyester, as in the case of the high stiffness polyester film, at least one aromatic dicarboxylic acid selected from terephthalic acid, isophthalic acid and 2,6-naphthalenedicarboxylic acid, and ethylene glycol, 1,3-propanediol and A polyester mainly composed of an aromatic polyester comprising at least one aliphatic alcohol selected from 1,4-butanediol is preferred. Examples of polyester include PET, PBT and the like. In addition, 51% by mass or more of the polyester in the stretched polyester film may be composed of one type of polyester, or may be composed of two or more types of polyester.

  The thickness of the stretched polyester film is preferably 9 μm or more, more preferably 12 μm or more. Further, the thickness of the stretched polyester film is preferably 25 μm or less, more preferably 20 μm or less. By setting the thickness of the stretched polyester film to 9 μm or more, the stretched polyester film has sufficient strength. When the thickness of the stretched polyester film is 25 μm or less, the stretched polyester film exhibits excellent moldability. Therefore, the process of manufacturing the bag 10 by processing the packaging material 30 can be efficiently performed.

  Preferably, the material constituting the stretched polyester film has a thermal conductivity equal to or higher than a predetermined value. For example, the thermal conductivity of the material constituting the stretched polyester film is preferably 0.05 W / m · K or more, and more preferably 0.1 W / m · K or more. The thermal conductivity of PET is, for example, 0.14 W / m · K. The thermal conductivity of PBT is higher than the thermal conductivity of PET, for example, 0.25 W / m · K. By using a material having a thermal conductivity equal to or higher than a predetermined value, the heat resistance of the packaging material 30 can be increased.

  The melting point of the stretched polyester film is preferably 200 ° C. or higher, more preferably 220 ° C. or higher. By setting the melting point of the stretched polyester film to 220 ° C. or higher, when heating the contents contained in the bag 10 manufactured using the packaging material 30, the stretched polyester film may have holes, The formation of wrinkles can be suppressed.

  When the stretched polyester film includes PET, the PET may include biomass-derived PET as in the case of the high stiffness polyester film described above. In this case, the stretched polyester film may be composed of only biomass-derived PET. Alternatively, the stretched polyester film may be composed of biomass-derived PET and fossil fuel-derived PET. The biomass-derived PET contained in the stretched polyester film, the biomass degree of the stretched polyester film, and the like are the same as those in the case of the above-described high stiffness polyester film, and thus description thereof is omitted.

  A stretched plastic film containing polyamide as a main component (hereinafter also referred to as a stretched polyamide film) contains, for example, 51% by mass or more of polyamide. Examples of the polyamide system include an aliphatic polyamide or an aromatic polyamide. Examples of the aliphatic polyamide include nylons such as nylon-6, nylon-6,6, and a copolymer of nylon-6 and nylon-6,6. As the aromatic polyamide, polymethaxylene adipamide ( MXD6). When the packaging material 30 includes the stretched polyamide film, the piercing strength of the packaging material 30 can be increased.

  The stretched polyamide film may be constituted by a single layer, or may be constituted by a plurality of layers. When the stretched polyamide film includes a plurality of layers, the stretched polyamide film is, for example, a co-extruded film produced by co-extrusion. The co-pressed film includes, for example, a first layer made of polyester such as PET, a second layer made of polyamide such as nylon, and a third layer made of polyester such as PET, which are sequentially laminated. When the mass of the second layer made of polyamide such as nylon is 51% or more of the mass of the whole co-pressed film, it can be said that the main component of the co-pressed film is polyamide.

An example of a combination of the first stretched plastic film 40 and the second stretched plastic film 50 in the present embodiment is as follows.

(First adhesive layer)
The first adhesive layer 45 includes an adhesive for bonding the first stretched plastic film 40 and the second stretched plastic film 50 by a dry lamination method. The adhesive constituting the first adhesive layer 45 is generated from an adhesive composition prepared by mixing a first composition containing a main agent and a solvent, and a second composition containing a curing agent and a solvent. Specifically, the adhesive includes a cured product generated by the reaction between the main agent and the solvent in the adhesive composition.

  Examples of the adhesive include polyurethane and the like. Polyurethane is a cured product generated by reacting a polyol as a main component with an isocyanate compound as a curing agent. Examples of polyurethane include polyether polyurethane, polyester polyurethane, and the like. The polyether polyurethane is a cured product generated by reacting a polyether polyol as a main component with an isocyanate compound as a curing agent. Polyester polyurethane is a cured product generated by the reaction between a polyester polyol as a main component and an isocyanate compound as a curing agent.

  Examples of the isocyanate compound include aromatic isocyanate compounds such as tolylene diisocyanate (TDI), 4,4′-diphenylmethane diisocyanate (MDI), and xylylene diisocyanate (XDI), hexamethylene diisocyanate (HDI), and isophorone diisocyanate (IPDI). Or an adduct or multimer of the above-mentioned various isocyanate compounds.

  The material forming the first adhesive layer 45 preferably has a higher thermal conductivity than the material forming the first stretched plastic film 40, the second stretched plastic film 50, and the sealant film 70. For example, the thermal conductivity of the material forming the first adhesive layer 45 is preferably 1.0 W / m · K or more, more preferably 3.0 W / m · K or more. The thermal conductivity of the polyurethane is in 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 first adhesive layer 45, when the bag 10 manufactured using the packaging material 30 is heated, the heat generated in the storage unit 17 is generated by the inner surface 30 x of the packaging material 30. Heat is easily diffused in the surface direction of the packaging material 30 while being transmitted from the side to the outer surface 30y side. Thereby, since the heat radiation of the packaging material 30 can be improved, the temperature rise 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 first adhesive layer 45 is preferably 2 μm or more, and more preferably 3 μm or more. Further, the thickness of the first adhesive layer 45 is preferably 6 μm or less, and more preferably 5 μm or less. By setting the thickness of the first adhesive layer 45 to 3 μm or more, diffusion of heat in the surface direction of the packaging material 30 is more likely to occur.

(Second adhesive layer)
The second adhesive layer 55 includes an adhesive for bonding the second stretched plastic film 50 and the sealant film 70 by a dry lamination method. As an example of the adhesive of the second adhesive layer 55, polyurethane can be used as in the case of the first adhesive layer 45. In addition to the configuration, material, and characteristics described below, the same configuration, material, and characteristics of the second adhesive layer 55 as those of the first adhesive layer 45 can be employed.

  Like the first adhesive layer 45, the material forming the second adhesive layer 55 preferably has a higher heat than the material forming the first stretched plastic film 40, the second stretched plastic film 50, and the sealant film 70. Has conductivity. For example, the thermal conductivity of the material forming the second adhesive layer 55 is preferably 1 W / m · K or more, and more preferably 3 W / m · K or more.

  The thickness of the second adhesive layer 55 is preferably 2 μm or more, more preferably 3 μm or more. Further, the thickness of the second adhesive layer 55 is preferably 6 μm or less, more preferably 5 μm or less.

  By the way, as described above, an aromatic isocyanate compound and an aliphatic isocyanate compound exist as the isocyanate compound constituting the curing agent of the adhesive. Among these, in the aromatic isocyanate compound, components that cannot be used for food use elute under a high temperature environment such as heat sterilization. Incidentally, the second adhesive layer 55 is in contact with the sealant film 70. For this reason, when the second adhesive layer 55 contains an aromatic isocyanate compound, the components eluted from the aromatic isocyanate compound adhere to the contents contained in the container 17 in contact with the sealant film 70. There is.

  In consideration of such a problem, preferably, as an adhesive constituting the second adhesive layer 55, a cured product generated by a reaction between a polyol as a main agent and an aliphatic isocyanate compound as a curing agent Is used. Accordingly, it is possible to prevent components that cannot be used for food use due to the second adhesive layer 55 from adhering to the contents.

(Sealant film)
Next, the sealant film 70 will be described. As a material of the sealant film 70, one or more resins selected from polyethylene and polypropylene such as low-density polyethylene and linear low-density polyethylene can be used. The sealant film 70 may be a single layer or a multilayer. Further, the sealant film 70 is preferably made of an unstretched film. The term “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 tension applied during film formation.

The bag 10 made of the packaging material 30 may be subjected to a sterilization treatment such as a boil treatment or a retort treatment at a high temperature. The sealant film 70 preferably has heat resistance to withstand these high-temperature treatments. The retort treatment is a treatment in which the bag 10 is filled with the contents, the bag 10 is sealed, and then the bag 10 is heated in a pressurized state using steam or 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 the contents, sealing the bag 10, and then baking the bag 10 under atmospheric pressure. The temperature of the boiling process is, for example, 90 ° C. or more and 100 ° C. or less.

  The melting point of the material constituting the sealant film 70 is preferably 150 ° C. or higher, and more preferably 160 ° C. or higher. By increasing the melting point of the sealant film 70, the retort treatment of the bag 10 can be performed at a high temperature, so that the time required for the retort treatment can be shortened. Note that the melting point of the material forming the sealant film 70 is lower than the melting point of the resin forming the stretched plastic films 40 and 50.

  When considered from the viewpoint of the retort treatment, a material containing propylene as a main component can be used as a material constituting the sealant film 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 the material containing propylene as a main component include propylene / ethylene block copolymer, propylene / ethylene random copolymer, polypropylene such as homopolypropylene, or a mixture of polypropylene and polyethylene. Can be. Here, “propylene / ethylene block copolymer” means a material having a structural formula represented by the following formula (I). The “propylene / ethylene random copolymer” means a material having a structural formula represented by the following formula (II). “Homopolypropylene” means a material having a structural formula represented by the following formula (III).

  When a mixture of polypropylene and polyethylene is used as the material mainly containing propylene, the material may have a sea-island structure. Here, the “sea-island structure” refers to a structure in which polyethylene is discontinuously dispersed in a region where polypropylene is continuous.

When considered from the viewpoint of the boil treatment, examples of the material constituting the sealant film 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 mentioned as the materials constituting the sealant film 70 from the viewpoint of the retort treatment described above. The material constituting the sealant film 70 has a melting point of, for example, 100 ° C. or more, more preferably 105 ° C. or more, and still more preferably 110 ° C. or more. When polyethylene is used as the material forming the sealant film 70, a melting point of 100 ° C. or more can be realized, for example, when the density of polyethylene is 0.920 g / cm ³ or more. Further, specific examples of the sealant film for forming the sealant film 70 having a melting point of 100 ° C. or higher include TUX-HC manufactured by Mitsui Chemicals Tosello, L6101 manufactured by Toyobo, and LS700C manufactured by Idemitsu Unitech. Specific examples of the sealant film for forming the sealant film 70 having a melting point of 105 ° C. or more include NB-1 manufactured by Tamapoly. Specific examples of the sealant film for forming the sealant film 70 having a melting point of 110 ° C. or more include LS760C manufactured by Idemitsu Unitech and TUX-HZ manufactured by Mitsui Chemicals Tosello.

Preferably, the sealant film 70 is a single-layer film including a propylene / ethylene block copolymer. For example, the sealant film including the sealant film 70 is a single-layer unstretched film mainly composed of a propylene / ethylene block copolymer.
By using the propylene / ethylene block copolymer, the impact resistance of the sealant film can be enhanced, and thereby, it is possible to suppress the bag 10 from being broken due to the impact at the time of falling. In addition, the piercing resistance of the packaging material 30 can be improved.

  The propylene / ethylene block copolymer includes, for example, a sea component composed of polypropylene and an island component composed of an ethylene / propylene copolymer rubber component. The sea component can contribute to enhancing the blocking resistance, heat resistance, rigidity, seal strength, and the like of the propylene / ethylene block copolymer. In addition, the island component can contribute to enhancing the impact resistance of the propylene / ethylene block copolymer. Therefore, by adjusting the ratio of the sea component and the island component, the mechanical properties of the sealant film containing the propylene / ethylene block copolymer can be adjusted.

In the propylene / ethylene block copolymer, the mass ratio of the sea component composed of polypropylene is higher than the mass ratio of the island component composed of the ethylene / propylene copolymer rubber component.
For example, in the propylene / ethylene block copolymer, the mass ratio of the sea component composed 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 film may further include 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 an α-olefin copolymer and polyethylene. The α-olefin copolymer is, for example, a linear low-density polyethylene. Examples of polyethylene include low density polyethylene, medium density polyethylene, and high density polyethylene. The second thermoplastic resin can contribute to enhancing the impact resistance of the sealant film.

The low-density polyethylene, density of 0.910 g / cm ³ or more and 0.925 g / cm ³ or less of polyethylene. The medium density polyethylene is a polyethylene having a density of 0.926 g / cm ³ or more and 0.940 g / cm ³ or less. The high-density polyethylene is a polyethylene having 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 a medium or low pressure of 1 atm or more and less than 1000 atm.

The medium density polyethylene and the high density polyethylene may partially include a copolymer of ethylene and an α-olefin. Further, even when ethylene is polymerized at a medium pressure or a low pressure, when a copolymer of ethylene and an α-olefin is contained, a medium- or low-density polyethylene can be produced. Such polyethylene is referred to as the above-mentioned linear low-density polyethylene. The linear low-density polyethylene is obtained by copolymerizing an α-olefin with a linear polymer obtained by polymerizing ethylene at a medium pressure or a low pressure to introduce short-chain branches. Examples of the α-olefin 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 a structural formula represented by the following formula (IV).

Each of R ₁ and R ₂ is H (hydrogen atom) or an alkyl group such as CH ₃ and C ₂ H ₅ . Also, j and k are each an integer of 1 or more. J is larger than k. That is, in the α-olefin copolymer represented by the formula (IV), the structure on the left side including R ₁ is the base. R ₁ is for example H and R ₂ is for example C ₂ H ₅ .

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

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

  In addition, the sealant film 70 may further include a thermoplastic elastomer. By using a thermoplastic elastomer, the impact resistance and piercing resistance of the sealant film 70 can be further improved.

  The thermoplastic elastomer is, for example, a hydrogenated styrene-based thermoplastic elastomer. The hydrogenated styrene-based thermoplastic elastomer has a structure comprising at least one polymer block A mainly composed of a vinyl aromatic compound and at least one polymer block B mainly composed of a hydrogenated conjugated diene compound. . Further, the thermoplastic elastomer may be an ethylene / α-olefin elastomer. The 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 a main component and α-olefin as a comonomer. is there.

  In addition, the sealant film 70 may further include a crystallization accelerator. By using a crystallization accelerator, the tensile modulus of the sealant film 70 can be increased. Thereby, the tearability of the sealant film 70 and the packaging material 30 can be improved. The crystallization accelerator is, for example, a metal salt of a phosphoric acid ester or a metal salt of benzoic acid.

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

  Examples of the method for producing the propylene / ethylene block copolymer include a method in which a raw material such as propylene or ethylene is polymerized using a catalyst. As the catalyst, a Ziegler-Natta type, metallocene catalyst or the like can be used.

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

Hereinafter, preferable mechanical properties of the single-layer sealant film containing the propylene / ethylene block copolymer will be described.
The tensile modulus (MPa) at 25 ° C. of the sealant film 70 in the machine direction (MD) is at least 500 MPa or more. The tensile modulus (MPa) at 25 ° C. of the sealant film 70 in the flow direction (MD) may be 600 MPa or more, 700 MPa or more, 800 MPa or more, or 900 MPa or more. In particular, when the thickness of the single-layer sealant film 70 is 50 μm, a material containing a propylene / ethylene block copolymer that has a tensile modulus (MPa) of 800 MPa or more in the machine direction (MD) may be used. preferable. The product of the tensile modulus (MPa) of the sealant film 70 in the flow direction (MD) and the thickness (μm) of the sealant film 70 is at least 35,000 or more. The product of the tensile modulus (MPa) of the sealant film 70 and the thickness (μm) of the sealant film 70 in the flow direction (MD) may be 38000 or more, 42,000 or more, 45000 or more, or 48000 or more.
Further, the tensile modulus (MPa) at 25 ° C. of the sealant film 70 in the vertical direction (TD) is at least 450 MPa. The tensile modulus (MPa) at 25 ° C. of the sealant film 70 in the vertical direction (TD) may be 500 MPa or more, 550 MPa or more, 600 MPa, 650 MPa or more, or 700 MPa or more. In particular, when the thickness of the single-layer sealant film 70 is 50 μm, a material including a propylene / ethylene block copolymer that has a tensile modulus (MPa) in the vertical direction (TD) of 650 MPa or more is used. preferable. The product of the tensile modulus (MPa) of the sealant film 70 and the thickness (μm) of the sealant film 70 in the vertical direction (TD) is at least 25,000 or more. The product of the tensile modulus (MPa) of the sealant film 70 and the thickness (μm) of the sealant film 70 in the vertical direction (TD) may be 30,000 or more, 35,000 or more, or 38,000 or more.
Since the sealant film 70 has a high tensile modulus, the tearing property when the bag 10 is opened can be improved.

The tensile elongation (%) at 25 ° C. of the sealant film 70 in the flow direction (MD) is preferably 1100 (%) or less, more preferably 1000 (%) or less, and 900 (%) or less. Or 800 (%) or less. Further, the product of the tensile elongation (%) of the sealant film 70 and the thickness (μm) of the sealant film 70 in the flow direction (MD) is preferably 55,000 or less, more preferably 50,000 or less. Further, the tensile elongation (%) at 25 ° C. of the sealant film 70 in the vertical direction (TD) is preferably 1200 (%) or less, more preferably 1100 (%) or less, and 1000 (%) or less. Or 900 (%) or less. The product of the tensile elongation (%) of the sealant film 70 and the thickness (μm) of the sealant film 70 in the vertical direction (TD) is preferably 60,000 or less, more preferably 55,000 or less.
In the bag 10 shown in FIG. 1, the first direction D1 corresponds to the flow direction (MD) of the sealant film 70. Further, the second direction D2 corresponds to the vertical direction (TD) of the sealant film 70.

  The tensile modulus and tensile elongation can be measured according to JIS K7127. As a measuring device, a tensile tester STA-1150 manufactured by Orientec can be used. In the bag 10 shown in FIG. 1, the direction in which the upper portion 11 and the lower portion 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 portions 13 extend is the direction in which the sealant film or the like extends. , The vertical direction of the film constituting the bag 10. Although not shown, the bag 10 may be configured so that the direction in which the upper portion 11 and the lower portion 12 extend is the vertical direction of the film, and the direction in which the side portions 13 extend is the film flow direction.

(Other layers)
The packaging material 30 may further include a printing layer 36. In the example shown in FIG. 2, the print layer 36 is located between the first stretched plastic film 40 and the first adhesive layer 45.

  The printing layer 36 is a layer provided on the packaging material 30 in order to show information on the contents and the packaged product in the bag 10 and to give an aesthetic effect. The printing layer expresses characters, numbers, symbols, figures, patterns, and the like. As a material constituting the print layer, an ink for gravure printing or an ink for flexographic printing can be used. Specific examples of the gravure printing ink include Finart manufactured by DIC Graphics Co., Ltd.

  FIG. 9 is a cross-sectional view illustrating a modified example of the layer configuration of the packaging material 30. As shown in FIG. 9, the packaging material 30 may include a vapor deposition layer 37 located on a surface on the inner surface 30x side of the first stretched plastic film 40. Further, the packaging material 30 may further include a transparent gas barrier coating film 38 which is located on the surface of the vapor deposition layer 37 and has transparency.

  FIG. 10 is a cross-sectional view illustrating a modified example of the layer configuration of the packaging material 30. As shown in FIG. 10, the vapor deposition layer 37 may be located on a surface on the outer surface 30y side of the second stretched plastic film 50. Further, a gas barrier coating film 38 may be provided on the surface of the evaporation layer 37.

  Hereinafter, the vapor deposition layer 37 and the gas barrier coating film 38 will be described.

  The vapor deposition layer 37 is a layer provided on the packaging material 30 to enhance the gas barrier properties of the packaging material 30. As a material for forming the deposition layer 37, a 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 substance such as aluminum oxide (aluminum oxide) and silicon oxide. In particular, when the printing layer 36 is provided on the inner surface 30x side of the vapor deposition layer 37, the vapor deposition layer 37 is configured as a transparent vapor deposition layer.

  The vapor deposition layer 37 functions as a layer having a gas barrier function of preventing permeation of oxygen gas, water vapor, and the like. Note that two or more evaporation layers 37 may be provided. When two or more vapor deposition layers 37 are provided, each may 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 vapor deposition method, a sputtering method, and an ion plating method, a plasma chemical vapor deposition method, Chemical vapor deposition (Chemical Vapor Deposition, CVD) such as chemical vapor deposition and photochemical vapor deposition. Specifically, a deposition layer can be formed on a deposition roller using a roller deposition film deposition apparatus. The thickness of the vapor deposition layer 37 is, for example, 20 ° or more and 200 °, preferably 30 ° or more and 150 °, and more preferably 50 ° or more and 120 ° or less. The thickness of the vapor deposition layer 37 can be measured by a fundamental parameter method using, for example, a fluorescent X-ray analyzer (trade name: RIX2000, manufactured by Rigaku Corporation).

The gas barrier coating film 38 is a layer that functions as a layer that suppresses transmission of oxygen gas, water vapor, and the like. The gas barrier coating film 38 has a general formula R ¹ _nM (OR ² ) _m (where 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 a valence of M.) and at least one alkoxide represented by the above formula and the polyvinyl alcohol as described above. A transparent gas barrier composition containing a polyether-based resin and / or an ethylene-vinyl alcohol copolymer, and which is polycondensed by a sol-gel method in the presence of a sol-gel method catalyst, an acid, water, and an organic solvent. Can be

Next, the layer configuration of the lower film 16 will be described.

  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, similarly to the front film 14 and the back film 15, the above-described packaging material 30 may be used as the lower film 16. Alternatively, a film having an inner surface made of a sealant film and having a configuration different from that of the packaging material 30 may be used as the lower film 16.

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

  First, the above-described first stretched plastic film 40 and second stretched plastic film 50 are prepared. The first stretched plastic film 40 or the second stretched plastic film 50 is provided with a printing layer 36, a vapor deposition layer 37, a gas barrier coating film 38, and the like as necessary.

  Subsequently, the first stretched plastic film 40 and the second stretched plastic film 50 are laminated via the first adhesive layer 45 by a dry lamination method. Thereafter, a laminate including the first stretched plastic film 40 and the second stretched plastic film 50 and the sealant film 70 are laminated via the second adhesive layer 55 by a dry lamination method. Thereby, the packaging material 30 including the first stretched plastic film 40, the second stretched plastic film 50, and the sealant film 70 can be obtained.

  Alternatively, first, the second stretched plastic film 50 and the sealant film are laminated by a dry lamination method via the second adhesive layer 55, and then the first stretched plastic film 40, the second stretched plastic film 50, and the sealant film are laminated. The packaging material 30 may be manufactured by laminating with a laminated body via the first adhesive layer 45 by a dry lamination method.

  In the dry lamination method, first, an adhesive composition is applied to one of 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, aging is performed for at least 24 hours in an environment of, for example, 20 ° C. or more while the two laminated films are wound up.

Method for producing a bag Next, a method for producing the bag 10 with the packaging material 30 described above. First, the front film 14 and the back film 15 made of the packaging material 30 are prepared. In addition, the folded lower film 16 is inserted between the front film 14 and the back film 15. Subsequently, the inner surfaces of the respective films are heat-sealed to form seal portions such as a lower seal portion 12a and a side seal portion 13a. In addition, the films bonded to each other by heat sealing are cut into an appropriate shape to obtain the bag 10 shown in FIG. Subsequently, the contents 18 are filled into the bag 10 through the opening 11b of the upper part 11. The contents 18 are, for example, cooked foods containing moisture, such as curries, stews, and soups. Further, the contents 18 may include a material containing a large amount of oil, such as meat, fish, and a seasoning therefor. In addition to food, what can be heated by hot water etc. can be stored in the bag 10 as contents. Further, contents that do not require heating may be stored in the bag 10. Then, the upper part 11 is heat-sealed to form an upper seal part. Thus, the sealed bag 10 in which the contents 18 are stored can be obtained.

  In the present embodiment, a high stiffness polyester film is used as the first stretched plastic film 40 or the second stretched plastic film 50 of the packaging material 30 forming the bag 10. For this reason, the packaging material 30 and the bag 10 can have rigidity and puncture resistance. Thereby, for example, when a sharp member having a sharp tip contacts the bag 10, the bag 10 can be prevented from being broken. The piercing strength of the packaging material 30 is preferably 14 N or more, more preferably 15 N or more, even more preferably 16 N or more or 17 N or more. A method for measuring the piercing strength will be described in an example described later.

Next, a method of opening the bag 10 will be described. Here, a case where the consumer opens the bag 10 by tearing the bag 10 along the first direction D1 will be described. In the present embodiment, as described above, the sealant film 70 of the packaging material 30 constituting the bag 10 has a high tensile modulus. For this reason, the packaging material 30 and the bag 10 can be made tearable. Thereby, for example, when the consumer tears and opens the bag 10, the tearing direction can be suppressed from deviating from the first direction D1.

(Modification of layer structure of packaging material)
In the above-described first embodiment, an example in which a high stiffness polyester film is used as one of the first stretched plastic film 40 and the second stretched plastic film 50 has been described. However, the present invention is not limited to this, and neither the first stretched plastic film 40 nor the second stretched plastic film 50 may include the high stiffness polyester film. Even in this case, since the sealant film 70 of the packaging material 30 constituting the bag 10 has a high tensile elasticity, the packaging material 30 and the bag 10 can have tearability.

Second Embodiment Next, a second embodiment of the present invention will be described. In the above-described first embodiment, an example has been described in which the base material of the packaging material has two plastic films. In this embodiment, an example in which the base material of the packaging material has only one plastic film will be described. In this embodiment, the same portions as those in the first embodiment are denoted by the same reference numerals, and detailed description is omitted. Further, when it is clear that the operation and effect obtained in the first embodiment can also be obtained in this embodiment, the description thereof may be omitted.

  FIG. 11 is a cross-sectional view illustrating an example of a layer configuration of the packaging material 30 according to the second embodiment. As shown in FIG. 11, the packaging material 30 includes at least a stretched plastic film 60, an adhesive layer 65, and a sealant film 70 arranged in order from the outer surface 30y side to the inner surface 30x side. As in the case of the first embodiment, the packaging material 30 is manufactured by laminating the stretched plastic film 60 and the sealant film 70 via the adhesive layer 65 by a dry lamination method. The thickness of the packaging material 30 is, for example, 60 μm or more, 70 μm or more, 80 μm or more, or 90 μm or more. The thickness of the packaging material 30 may be 120 μm or less, 110 μm or less, or 100 μm or less.

(Stretched plastic film)
The stretched plastic film 60 is a plastic film stretched in a predetermined direction, like the first stretched plastic film 40 and the second stretched plastic film 50 described above. The stretched plastic film 60 is not particularly limited as in the case of the first stretched plastic film 40 and the second stretched plastic film 50.

  The stretched plastic film 60 contains, for example, polyester as a main component. For example, the stretched plastic film 60 contains 51% by mass or more of polyester. Examples of the polyester include PET and PBT as in the case of the first stretched plastic film 40. When the stretched plastic film 60 contains polyester as a main component, the same structure, material, and characteristics of the stretched plastic film 60 as those of the first stretched plastic film 40 can be employed. The above-described high stiffness polyester film may be used as the stretched plastic film 60. Thereby, the packaging material 30 and the bag 10 can have rigidity and puncture resistance. Thereby, for example, when a sharp member having a sharp tip contacts the bag 10, the bag 10 can be prevented from being broken. The piercing strength of the packaging material 30 of the present embodiment is preferably 12N or more, and more preferably 13N or more.

  When the stretched plastic film 60 contains polyester as a main component, the thickness of the stretched plastic film 60 is preferably 9 μm or more, more preferably 12 μm or more. When the stretched plastic film 60 contains polyester as a main component, the thickness of the stretched plastic film 60 is preferably 25 μm or less, more preferably 20 μm or less. When the stretched plastic film 60 contains polyester as a main component, the thermal conductivity of the stretched plastic film 60 is preferably 0.05 W / m · K or more, more preferably 0.1 W / m · K or more. When the stretched plastic film 60 contains polyester as a main component, the melting point of the stretched plastic film 60 is preferably 200 ° C. or more, more preferably 220 ° C. or more.

  The stretched plastic film 60 may include PET derived from biomass as in the case of the first embodiment described above. In this case, the stretched plastic film 60 may be composed of only biomass-derived PET. Alternatively, the stretched plastic film 60 may be composed of PET derived from biomass and PET derived from fossil fuel. The biomass-derived PET contained in the stretched plastic film 60, the biomass degree of the stretched plastic film 60, and the like are the same as those in the case of the high stiffness polyester film of the above-described first embodiment, and a description thereof will be omitted.

  The stretched plastic film 60 may contain polyamide as a main component. For example, the stretched plastic film 60 contains 51% by mass or more of polyamide. Examples of the polyamide system include an aliphatic polyamide or an aromatic polyamide. Examples of the aliphatic polyamide include nylons such as nylon-6, nylon-6,6, and a copolymer of nylon-6 and nylon-6,6. As the aromatic polyamide, polymethaxylene adipamide ( MXD6). When the stretched plastic film 60 contains polyamide as a main component, the piercing strength of the packaging material 30 including the stretched plastic film 60 can be increased.

  When the stretched plastic film 60 contains polyamide as a main component, the thickness of the stretched plastic film 60 is preferably 12 μm or more, more preferably 15 μm or more. When the stretched plastic film 60 contains polyamide as a main component, the thickness of the stretched plastic film 60 is preferably 25 μm or less, more preferably 20 μm or less. When the stretched plastic film 60 contains polyamide as a main component, the thermal conductivity of the stretched plastic film 60 is preferably 0.25 W / m · K or more, more preferably 0.3 W / m · K or more. is there. The thermal conductivity of nylon is, for example, 0.35 W / m · K.

  The stretched plastic film 60 may be constituted by a single layer, or may be constituted by a plurality of layers. When the stretched plastic film 60 includes a plurality of layers, the stretched plastic film 60 is, for example, a co-extruded film manufactured by co-extrusion. The stretched plastic film 60 produced by co-extrusion includes, for example, a first layer made of polyester such as PET, a second layer made of polyamide such as nylon, and a third layer made of polyester such as PET.

(Adhesive layer)
The adhesive layer 65 includes an adhesive for bonding the stretched plastic film 60 and the sealant film 70 by a dry lamination method. As an example of the adhesive of the adhesive layer 65, as in the case of the above-described first adhesive layer 45, polyurethane can be used. With respect to the configuration, material, and characteristics of the adhesive layer 65, those similar to the first adhesive layer 45 can be employed. The thickness of the adhesive layer 65 is preferably 2 μm or more, and more preferably 3 μm or more. The thickness of the adhesive layer 65 is preferably 6 μm or less, more preferably 5 μm or less.

(Sealant film)
As a material constituting the sealant film 70, as in the case of the first embodiment, one or two or more resins selected from polyethylene such as low-density polyethylene and linear low-density polyethylene, and polypropylene are used. Can be used. The sealant film 70 may be a single layer or a multilayer. The thickness of the sealant film 70 is preferably 30 μm or more, and more preferably 40 μm or more. Further, the thickness of the sealant film 70 is preferably 100 μm or less, and more preferably 80 μm or less. As the configuration, material, and characteristics of the sealant film 70, those similar to the sealant film 70 of the first embodiment can be adopted. That is, it is preferable to employ the sealant film 70 having a high tensile modulus. Thereby, the packaging material 30 and the bag 10 can be made to have a tearing property. For example, when the consumer tears and opens the bag 10, the tearing direction is deviated from the first direction D1. Can be suppressed.

(Other layers)
As shown in FIG. 11, the packaging material 30 may further include a printed layer 36 provided on the stretched plastic film 60. In addition, as shown in FIG. 12, 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. Further, the packaging material 30 may further include a transparent gas barrier coating film 38 which is located on the surface of the vapor deposition layer 37 and has transparency.

(Modification)
Various changes can be made to each of the above-described embodiments. Hereinafter, modified examples will be described 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 the corresponding parts in each of the above-described embodiments will be used for parts that can be configured similarly to the above-described embodiments. , And redundant description will be omitted. Further, when it is clear that the operation and effect obtained in each of the above-described embodiments can be obtained also in the modified example, the description thereof may be omitted.

(Modification of bag)
FIG. 13 is a diagram illustrating another example of the bag 10 including the packaging material 30. The bag 10 shown in FIG. 13 is different from the bag 10 shown in FIG. 1 only in that the bag 10 further includes a steam release mechanism 20. In the bag 10 shown in FIG. 13, the same parts as those of 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 content stored in the storage unit 17 to the outside. The steam release mechanism 20 allows the inside and the outside of the bag 10 to communicate with each other to release the steam when the pressure of the steam becomes equal to or higher than a predetermined value, and suppresses the escape of the steam from a portion other than the steam release mechanism 20. ,It is configured.

  When the bag 10 provided 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 such a degree that steam escapes from the steam venting mechanism 20 to the outside. That is, depending on how the bag 10 is used, there is a case where the probability that the steam release mechanism 20 exerts a function of releasing steam to the outside is low. Even in this case, by providing the steam release mechanism 20 in the bag 10, it is possible to further reduce the probability that steam escapes from a portion other than the steam release mechanism 20 or the bag 10 ruptures.

  In the example shown in FIG. 13, the steam release mechanism 20 includes a steam release seal portion 20 a protruding from the side seal portion 13 a toward the inside of the bag 10, and a non-sealing member separated from the housing portion 17 by the steam release seal portion 20 a. A part 20b. The non-seal portion 20b communicates with the outside of the bag 10. When the pressure in the housing portion 17 is increased by being heated by a microwave oven or the like, the steam release seal portion 20a peels off. The vapor in the storage portion 17 can escape to the outside of the bag 10 through the peeled portion of the vapor release seal portion 20a and the non-seal portion 20b. At this time, since the packaging material 30 has heat resistance, it is possible to suppress the opening of the packaging material 30 and the formation of wrinkles in the packaging material 30 during heating.

  The configuration of the steam venting mechanism 20 is not limited to the configuration shown in FIG. The configuration of the steam venting mechanism 20 is arbitrary as long as the housing 17 and the outside of the bag 10 can be communicated when the steam pressure becomes equal to or higher than a predetermined value.

  For example, as shown in FIG. 14, the surface film 14 may include a joint portion 14a in which the inner surfaces of the surface film 14 are partially overlapped. The joint portion 14a can be configured by, for example, folding back at a folding portion 14f so as to form a fold on one surface film 14. Further, the joint portion 14a may be configured by overlapping a part of the two surface films 14.

  The palm joint portion 14a is formed with a palm joint seal portion 14b extending from one side seal portion 13a to the other side seal portion 13a. In this case, the steam release mechanism 20 includes, for example, a steam release seal portion 20a protruding from the gas seal portion 14b toward the housing portion 17, and a non-sealing portion 20b surrounded by the steam release seal portion 20a and the gas seal portion 14b. And a notch 20c formed in the surface film 14 in the non-seal portion 20b. As shown in FIG. 14, among the plurality of non-seal portions 14 c located at the joint portion 14 a between the side portion 13 and the steam release mechanism 20, the surface film 14 is also the most non-seal portion 14 c of the steam release mechanism 20. The cut 14d may be formed in the hole.

  Also in the present modified example, when the pressure of the housing portion 17 increases, the steam release seal portion 20a peels off, and the housing portion 17 and the non-sealing portion 20b communicate with each other. The steam that has flowed into the non-seal portion 20b from the storage portion 17 through the peeling portion of the steam release seal portion 20a passes through the cut 20c and escapes to the outside of the bag 10.

  The bag 10 shown in FIG. 14 is arranged in a microwave oven such that the back film 15 contacts a turntable or a lower surface (flat table) of the microwave oven over a wide area. Therefore, the contents are more easily heated uniformly than the self-standing bag 10 as shown in FIG. Further, since the area of the portion where the bag 10 is 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 state in which the content is attached to the inner surface of the front film 14 or the back film 15 above the liquid level of the content is less likely to occur. Accordingly, it is possible to suppress the occurrence of a phenomenon in which the content adhering to the inner surface of the front film 14 or the back film 15 is excessively heated and a hole is formed in the front film 14 or the back film 15.

  FIG. 15A and FIG. 15B are a longitudinal 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 produced by sheet molding 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 and a side surface 112b, and a flange portion 113 that extends horizontally outward from the upper end of the side surface 112b. The lid 114 is joined to the upper surface of the flange 113 of the container body 112 via a seal 116. The lid 114 may include the packaging material 30 described above.

(Other variations of bags)
In the above-described embodiment, an example in which the bag 10 is a gusset-type bag has been described, 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 the front film 14 and the back film 15 made of the packaging material 30 at the upper part 11, the lower part 12, and the side part 13.

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

  Examples A1 to A3 and Comparative Example A1 described below are examples relating to the case where the number of the plastic films constituting the base material of the packaging material 30 is two as described in the first embodiment. Further, Example B1 and Comparative Examples B1 and B2 are examples relating to the case where only one plastic film is used as the base material of the packaging material 30 described in the second embodiment. First, Examples A1 to A3 and Comparative Example A1 will be described.

(Example A1)
As the first stretched plastic film 40, a high stiffness polyester film having a loop stiffness of 0.0017 N or more and made of PET (hereinafter, also referred to as a high stiffness PET film) was prepared. Subsequently, a print layer 36 having a thickness of 1 μm was formed on the surface of the high stiffness PET film.
As the high stiffness PET film, specifically, XP-55 manufactured by Toray Industries, Inc. was used. The thickness of the high stiffness PET film was 16 μm. The measured value of the loop stiffness of the high stiffness PET film was 0.0021 N in both the flow direction and the vertical direction. The Young's modulus of the high stiffness PET film in the flow direction was 4.8 GPa, and the Young's modulus of the high stiffness polyester film in the vertical direction was 4.7 GPa.
The tensile strength of the high stiffness PET film in the flow direction was 292 MPa, and the tensile strength of the high stiffness polyester film in the vertical direction was 257 MPa. The tensile elongation of the high stiffness PET film in the flow direction was 107%, and the tensile elongation of the high stiffness polyester film in the vertical direction was 102%. In this case, the value obtained by dividing the tensile strength of the high stiffness PET film in the flow direction by the tensile elongation was 2.73 [MPa /%], and the tensile strength of the high stiffness PET film in the vertical direction was divided by the tensile elongation. The value is 2.52 [MPa /%].
The heat shrinkage of the high stiffness PET film in the flow direction and the vertical direction was 0.4%.
A biaxially stretched PET film having a thickness of 12 μm was prepared as the second stretched plastic film 50.

  Further, as the sealant film 70, an unstretched polypropylene film ZK500R manufactured by Toray Film Processing Co., Ltd. was prepared. ZK500R contains the above-mentioned propylene / ethylene block copolymer and a crystallization accelerator. The thickness of the sealant film 70 was 50 μm.

  ZK500R has a high tensile modulus. Specifically, the tensile modulus of the ZK500R in the machine direction (MD) is 980 MPa when the thickness is 50 μm. The tensile modulus of the ZK500R in the vertical direction (TD) is 780 MPa when the thickness is 50 μm. Therefore, the product of the tensile modulus (MPa) and the thickness (μm) of the ZK500R in the flow direction is 49000 when the thickness is 50 μm. The product of the tensile modulus (MPa) and the thickness (μm) of the ZK500R in the vertical direction is 39000 when the thickness is 50 μm.

ZK500R also has a 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 the thickness (μm) of ZK500R in the flow direction is 38500 when the thickness is 50 μm. The product of the tensile elongation (%) and the thickness (μm) of the ZK500R in the vertical direction is 43500 when the thickness is 50 μm.

  Subsequently, the first stretched plastic film 40, the second stretched plastic film 50, and the sealant film 70 were laminated by a dry laminating method to produce a packaging material 30. As the first adhesive layer 45 and the second adhesive layer 55, a two-pack polyurethane adhesive (main agent: RU-40, curing agent: H-4) manufactured by Rock Paint Co., Ltd. was used. In addition, RU-40 of the main agent is a polyester polyol. The thickness of the first adhesive layer 45 and the second adhesive layer 55 was 3.5 μm. The thickness of the entire packaging material 30 was 86 μm.

[Evaluation of piercing resistance]
Subsequently, the piercing 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. 16, a semicircular needle 90 having a diameter of 1.0 mm and a tip shape radius of 0.5 mm is placed on a test piece of the packaging material 30 in a fixed state from the outer surface 30y side. Was pierced at a speed of 50 mm / min (50 mm per minute), and the maximum value of stress until the needle 90 penetrated the packaging material 30 was measured. The maximum value of the stress was measured for five or more test pieces, and the average value was defined as the piercing strength of the packaging material 30. The environment during the measurement was a temperature of 23 ° C. and a relative humidity of 50%. As a result, the piercing strength was 17.0N.

[Evaluation of loop stiffness]
Further, the loop stiffness in the flow direction and the vertical direction of the packaging material 30 was measured. As a measuring instrument, No. manufactured by Toyo Seiki Co., Ltd. was used. A 581 Loop Stefness Tester (registered trademark) LOOP STIFFNESS TESTER DA type was used. The environment during the measurement was a temperature of 23 ° C. and a relative humidity of 50%. As a result, the loop stiffness in the flow direction of the packaging material 30 was 0.121 N, and the loop stiffness in the vertical direction was 0.113 N. 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 0.00141 N / μm, and the value obtained by dividing the loop stiffness in the vertical direction by the thickness of the packaging material 30 is 0.00131 N. / Μm.

[Evaluation of tearability]
Subsequently, as shown in FIG. 17, the two packaging materials 30 joined via the sealant film 70 were cut out so that the width W3 was 15 mm and the length W4 was 100 mm, thereby producing a test piece 100. The direction of the width W3 of the test piece 100 is parallel to the second direction D2 shown in FIG. The direction of the length W4 of the test piece 100 is parallel to the flow direction (MD) when forming a film such as a stretched plastic film or a sealant film, and is parallel to the first direction D1 shown in FIG. It is. Subsequently, as shown in FIG. 17, a cut 28 was formed at the center of the test piece 100 in the direction of the width W3. Subsequently, the test piece 100 was torn by hand in the direction of the length W4 with the notch 28 as a starting point. As a result, the test piece 100 could be torn in the direction of the length W4 without the sealant film 70 of the packaging material 30 extending halfway. In addition, the positional deviation of the two packaging materials 30 in the direction of the width W3 at the torn portion was 5 mm or less.

[Evaluation of heat resistance]
Subsequently, the bag 10 was produced using the packaging material 30, and the heat resistance of the bag 10 was evaluated. Specifically, first, the bag 10 shown in FIG. The height S1 of the bag 10 was 145 mm and the width S2 was 150 mm. The height S3 of the folded lower film 16, that is, the height from the lower end of the bag 10 to the folded portion 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 is also referred to as an M-size bag 10. Subsequently, 100 g of an oil-rich content such as meat and miso was filled in the bag 10 and the upper portion 11 was heat-sealed to form an upper seal portion.

  Thereafter, the bag 10 containing the contents was heated for 2 minutes using a microwave oven having an output of 500 W, and it was confirmed whether or not the packaging material 30 constituting the bag 10 was damaged. The test was performed on 10 bags 10. As a result, it was confirmed that no damage such as a hole in the packaging material 30 or a wrinkle formed in the packaging material 30 occurred in ten of the ten bags 10.

(Example A2)
As the first stretched plastic film 40, the stretched PET film used as the second stretched plastic film 50 in Example A1 was used, and as the second stretched plastic film 50, the high stiffness used as the first stretched plastic film 40 in Example A1 A packaging material 30 was produced in the same manner as in Example A1, except that a PET film was used. The thickness of the entire packaging material 30 was 86 μm.

  Subsequently, the piercing strength of the packaging material 30 and the loop stiffness in the flow direction and the vertical direction were measured in the same manner as in Example A1. As a result, the piercing strength was 16.9 N, the loop stiffness in the flow direction was 0.123 N, and the loop stiffness in the vertical direction was 0.111 N. 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 0.00143 N / μm, and the value obtained by dividing the loop stiffness in the vertical direction by the thickness of the packaging material 30 is 0.00129 N. / Μm.

  Subsequently, the tearing property of the packaging material 30 was evaluated in the same manner as in Example A1. As a result, the test piece 100 could be torn in the direction of the length W4 without the sealant film 70 of the packaging material 30 extending halfway. In addition, the positional deviation of the two packaging materials 30 in the direction of the width W3 at the torn portion was 5 mm or less.

  Subsequently, the bag 10 was produced using the packaging material 30 in the same manner as in Example A1, and the heat resistance of the bag 10 was evaluated. The size of the bag 10 was M size as in the case of Example A1. As a result, it was confirmed that no damage such as a hole in the packaging material 30 or a wrinkle formed in the packaging material 30 occurred in ten of the ten bags 10.

(Example A3)
A packaging material 30 was produced in the same manner as in Example A1, except that an unstretched polypropylene film ZK207 manufactured by Toray Film Processing Co., Ltd. was used as the sealant film 70. ZK207 contains the above-mentioned propylene / ethylene block copolymer. The thickness of the sealant film 70 was 70 μm. The thickness of the entire packaging material 30 was 106 μm.

  ZK207 has a high tensile modulus. Specifically, the tensile modulus of the ZK207 in the machine direction (MD) is 780 MPa when the thickness is 50 μm, and 680 MPa when the thickness is 60 μm. The tensile modulus of the 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 the thickness (μm) of ZK207 in the flow direction is 39000 when the thickness is 50 μm and 40800 when the thickness is 60 μm. The product of the tensile modulus (MPa) and the 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 a 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 the tensile elongation (%) and the thickness (μm) of ZK207 in the flow direction is 39500 when the thickness is 50 μm and 43800 when the thickness is 60 μm. The product of the tensile elongation (%) and the thickness (μm) of ZK207 in the vertical direction is 51000 when the thickness is 50 μm and 52200 when the thickness is 60 μm.

  Subsequently, the piercing strength of the packaging material 30 and the loop stiffness in the flow direction and the vertical direction were measured in the same manner as in Example A1. As a result, the piercing strength was 16.8 N, the loop stiffness in the flow direction was 0.176 N, and the loop stiffness in the vertical direction was 0.153 N. 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 0.00166 N / μm, and the value obtained by dividing the loop stiffness in the vertical direction by the thickness of the packaging material 30 is 0.00144 N. / Μm.

  Subsequently, the tearing property of the packaging material 30 was evaluated in the same manner as in Example A1. As a result, the test piece 100 could be torn in the direction of the length W4 without the sealant film 70 of the packaging material 30 extending halfway.

  Subsequently, the bag 10 was produced using the packaging material 30 in the same manner as in Example A1, and the heat resistance of the bag 10 was evaluated. The size of the bag 10 was M size as in the case of Example A1. As a result, it was confirmed that wrinkles were formed in the packaging material 30, but there were no holes in the packaging material 30.

(Comparative Example A1)
Except that the stretched PET film having a thickness of 12 μm was used as the first stretched plastic film 40, and the unstretched polypropylene film ZK207 manufactured by Toray Film Processing Co., Ltd. was used as the sealant film 70, the same as in the case of Example A1. Thus, a packaging material 30 was produced. The thickness of the entire packaging material 30 was 102 m.

  Subsequently, the piercing strength and loop stiffness of the packaging material 30 were measured in the same manner as in Example A1. As a result, the piercing strength was 13.2 N, the loop stiffness in the flow direction was 0.151 N, and the loop stiffness in the vertical direction was 0.116 N. 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 0.00148 N / μm, and the value obtained by dividing the loop stiffness in the vertical direction by the thickness of the packaging material 30 is 0.00114 N. / Μm.

  Subsequently, the tearing property of the packaging material 30 was evaluated in the same manner as in Example A1. As a result, the sealant film 70 of the packaging material 30 was stretched on the way, and the test piece 100 could not be torn in the direction of the length W4.

  Subsequently, the bag 10 was produced using the packaging material 30 in the same manner as in Example A1, and the heat resistance of the bag 10 was evaluated. The size of the bag 10 was M size as in the case of Example A1. As a result, it was confirmed that wrinkles were formed in the packaging material 30, but there were no holes in the packaging material 30.

  18A and 18B collectively show the layer configurations and evaluation results of Examples A1 to A3 and Comparative Example A1. In FIGS. 18A and 18B, the components of the packaging material are described in order from the outer layer in the column of “Layer Configuration”. In the column of "heat resistance", when the packaging material 30 was not formed with holes and wrinkles, it was described as "great", and wrinkles were formed in the packaging material 30, but no holes were formed. In this case, it was described as "good", and when a hole and a wrinkle were formed in the packaging material 30, it was described as "bad".

  As can be seen from a comparison between Examples A1 to A3 and Comparative Example A1, by using ZK500R as the sealant film 70 of the packaging material 30 or by using a high stiffness polyester film as the stretched plastic film of the packaging material 30, It was possible to prevent the sealant film 70 from stretching when tearing. With respect to the tearing property, in Example A3, the test piece 100 could be smoothly torn over the entire area in the direction of the length W4, and thus the evaluation result was “good”. Further, in Examples A1 and A2, the test piece 100 can be smoothly torn over the entire area in the direction of the length W4, and the two packaging materials 30 constituting the test piece 100 in the direction of the width W3. Since the displacement amount was 5 mm or less, the evaluation result was "great". On the other hand, in Comparative Example A1, the sealant film 70 of the packaging material 30 stretched on the way, and the test piece 100 could not be smoothly torn over the entire area in the direction of the length W4. "Bad"

  Further, as can be seen from the comparison between Examples A1 to A3 and Comparative Example A1, the packaging material 30 including the high stiffness polyester film has a higher packaging material 30 than the case where the packaging material 30 does not include the high stiffness polyester film. Piercing strength of 14N or more, for example, 16N or more.

  Further, as can be seen from a comparison between Example A3 and Comparative Example A1, the wrapping of the wrapping material 30 due to the wrapping material 30 including the high stiffness polyester film compared to the case where the wrapping material 30 does not include the high stiffness polyester film. The stiffness was increased to 0.160 N or more, for example, 0.170 N or more in at least one direction. Further, the value obtained by dividing the loop stiffness of the packaging material 30 by the thickness of the packaging material 30 could be increased in at least one direction to 0.00150 N / μm or more, for example, 0.00160 N / μm or more.

  Next, Example B1 and Comparative Examples B1 and B2, which are described in the second embodiment and relate to the case where only one plastic film forms the base material of the packaging material, will be described.

(Example B1)
As the stretched plastic film 60, a high-stiffness PET film having a thickness of 16 μm, which was used as the first stretched plastic film 40 in Example A1, was prepared. Subsequently, a print layer 36 having a thickness of 1 μm was formed on the surface of the high stiffness PET film. Further, as the sealant film 70, an unstretched polypropylene film ZK500R manufactured by Toray Film Processing Co., Ltd. having a thickness of 50 μm and used as the sealant film 70 in Example A1 was prepared. Subsequently, the stretched plastic film 60 and the sealant film 70 were laminated via the adhesive layer 65 by a dry lamination method, and the packaging material 30 was produced. As the adhesive layer 65, a two-pack polyurethane adhesive (main agent: RU-40, curing agent: H-4) manufactured by Rock Paint Co., Ltd. was used. The thickness of the adhesive layer 65 was 3.5 μm. The thickness of the entire packaging material 30 was 70.5 μm.

  Subsequently, the piercing strength of the packaging material 30 and the loop stiffness in the flow direction and the vertical direction were measured in the same manner as in Example A1. As a result, the piercing strength was 13.6 N, the loop stiffness in the flow direction was 0.067 N, and the loop stiffness in the vertical direction was 0.057 N. 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 0.00095 N / μm, and the value obtained by dividing the loop stiffness in the vertical direction by the thickness of the packaging material 30 is 0.00081 N. / Μm.

  Subsequently, the tearing property of the packaging material 30 was evaluated in the same manner as in Example A1. As a result, the test piece 100 could be torn in the direction of the length W4 without the sealant film 70 of the packaging material 30 extending halfway.

  Subsequently, the bag 10 was produced using the packaging material 30 in the same manner as in Example A1, and the heat resistance of the bag 10 was evaluated. The size of the bag 10 was M size as in the case of Example A1. As a result, it was confirmed that wrinkles were formed in the packaging material 30, but there were no holes in the packaging material 30.

(Comparative Example B1)
A packaging material 30 was produced in the same manner as in Example B1, except that an unstretched polypropylene film ZK207 manufactured by Toray Film Processing Co., Ltd. was used as the sealant film 70. The thickness of the entire packaging material 30 was 90.5 μm.

  Subsequently, the piercing strength of the packaging material 30 and the loop stiffness in the flow direction and the vertical direction were measured in the same manner as in Example A1. As a result, the piercing strength was 13.2 N, the loop stiffness in the flow direction was 0.091 N, and the loop stiffness in the vertical direction was 0.088 N. 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 0.00129 N / μm, and the value obtained by dividing the loop stiffness in the vertical direction by the thickness of the packaging material 30 is 0.00125 N. / Μm.

  Subsequently, the tearing property of the packaging material 30 was evaluated in the same manner as in Example A1. As a result, the sealant film 70 of the packaging material 30 was stretched on the way, and the test piece 100 could not be torn in the direction of the length W4.

  Subsequently, the bag 10 was produced using the packaging material 30 in the same manner as in Example A1, and the heat resistance of the bag 10 was evaluated. The size of the bag 10 was M size as in the case of Example A1. As a result, it was confirmed that the packaging material 30 had holes and wrinkles.

(Comparative Example B2)
A biaxially stretched PET film having a thickness of 12 μm was used as the stretched plastic film 60, and the unstretched polypropylene film ZK207 manufactured by Toray Film Processing Co., Ltd. was used as the sealant film 70 in the same manner as in Example B1. Thus, a packaging material 30 was produced. The thickness of the entire packaging material 30 was 86.5 μm.

  Subsequently, the piercing strength of the packaging material 30 and the loop stiffness in the flow direction and the vertical direction were measured in the same manner as in Example A1. As a result, the piercing strength was 11.1 N, the loop stiffness in the flow direction was 0.071 N, and the loop stiffness in the vertical direction was 0.069 N. 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 0.00101 N / μm, and the value obtained by dividing the loop stiffness in the vertical direction by the thickness of the packaging material 30 is 0.00098 N. / Μm.

  Subsequently, the tearing property of the packaging material 30 was evaluated in the same manner as in Example A1. As a result, the sealant film 70 of the packaging material 30 was stretched on the way, and the test piece 100 could not be torn in the direction of the length W4.

  Subsequently, the bag 10 was produced using the packaging material 30 in the same manner as in Example A1, and the heat resistance of the bag 10 was evaluated. The size of the bag 10 was M size as in the case of Example A1. As a result, it was confirmed that wrinkles were formed in the packaging material 30, but there were no holes in the packaging material 30.

  19A and 19B collectively show the layer configurations and the evaluation results of Example B1 and Comparative Examples B1 and B2. As can be seen from the comparison between Example B1 and Comparative Examples B1 and B2, by using ZK500R as the sealant film 70 of the packaging material 30, it is possible to suppress the expansion of the sealant film 70 when the packaging material 30 is torn. did it.

  Further, as can be seen from a comparison between Example B1 and Comparative Example B2, when the packaging material 30 includes the high stiffness polyester film, the packaging material 30 pierces the packaging material 30 as compared with the case where the packaging material 30 does not include the high stiffness polyester film. The strength could be increased to 12N or more, for example, to 13N or more. In addition, the value obtained by dividing the loop stiffness of the packaging material 30 by the thickness of the packaging material 30 could be increased to at least 0.00085 N / μm, for example, at least 0.00090 N / μm in at least one direction.

DESCRIPTION OF SYMBOLS 10 Bag 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 Housing part 18 Contents 20 Steam release mechanism 20a Steam release seal part 25 Easy-opening means 26 Notch 30 Packaging material 35 Base material 36 Printing layer 37 Deposition layer 38 Gas barrier coating film 40 First stretched plastic film 45 First adhesive layer 50 Second stretched plastic film 55 Second adhesive layer 60 Stretched plastic film 70 Sealant film

Claims (14)

Packaging material,
With a base material and a sealant film,
The substrate has at least one stretched plastic film containing polyester or polyamide as a main component,
The sealant film includes a propylene / ethylene block copolymer,
A packaging material, wherein a product of a tensile modulus (MPa) of the sealant film in a flow direction and a thickness (μm) of the sealant film is 35,000 or more.   The packaging material according to claim 1, wherein a product of a tensile elastic modulus (MPa) of the sealant film in a flow direction and a thickness (μm) of the sealant film is 42000 or more. The base material has a first stretched plastic film and a second stretched plastic film located between the first stretched plastic film and the sealant film,
One of the first stretched plastic film or the second stretched plastic film contains polyester as a main component, and the other of the first stretched plastic film or the second stretched plastic film contains polyester or polyamide as a main component, The packaging material according to claim 1.   4. The high stretch stiffness polyester film according to claim 3, wherein one of the first stretched plastic film and the second stretched plastic film contains polyester as a main component and has a loop stiffness of 0.0017N or more in one direction. Packaging material.   The packaging material according to claim 4, wherein a value obtained by dividing a tensile strength of the high stiffness polyester film by a tensile elongation in at least one direction is 2.0 [MPa /%] or more.   The packaging material according to any one of claims 3 to 5, wherein the piercing strength of the packaging material is 14N or more.   The packaging material according to any one of claims 3 to 6, wherein a loop stiffness in one direction of the packaging material is 0.160 N or more.   The packaging material according to any one of claims 3 to 6, wherein a value obtained by dividing loop stiffness in one direction of the packaging material by a thickness of the packaging material is 0.00150 [N / μm] or more.   The packaging material according to claim 1, wherein the substrate has only one stretched plastic film.   The packaging material according to claim 9, wherein the stretched plastic film is a high-stiffness polyester film containing polyester as a main component and having a loop stiffness of 0.0017 N or more in one direction.   The packaging material according to claim 10, wherein a value obtained by dividing a tensile strength of the high stiffness polyester film by a tensile elongation in at least one direction is 2.0 [MPa /%] or more.   The packaging material according to any one of claims 9 to 11, wherein the piercing strength of the packaging material is 12N or more.   The packaging material according to any one of claims 9 to 12, wherein a value obtained by dividing loop stiffness in one direction of the packaging material by a thickness of the packaging material is equal to or greater than 0.00085 [N / μm].   A bag comprising the packaging material according to any one of claims 1 to 13.