Pouch

Abstract

To suppress the progress of delamination of the seal parts other than the intermediate portion.SOLUTION: A fifth dimension (S5) is the distance between the lower end of the inner edge of the first lower sealing portion and the folded portion. A seventh dimension (S7) is the distance between a center point (C1) of the housing portion and the inner edge of the first side sealing portion. An eighth dimension (S8) is calculated based on the following formula. S8=((S7)2-(S5)2)0.5. A tenth dimension (S10) is the distance between the inner edge of the upper seal portion and the lower end of the inner edge of the intermediate portion. The eleventh dimension (S11) is the distance between the lower end of the inner edge of the first lower seal portion and the lower end of the inner edge of the intermediate portion. A first approximate volume (V1) is calculated based on the following formula: V1=3.14×S5×S8×S11 + S5×S10×S8×2. A first parameter (U1), which is the ratio of the eighth dimension (S8) [mm] to the first approximate volume (V1) [mm3], is 7.000×10-5[mm -2] or greater.SELECTED DRAWING: Figure 1

Description

Technical Field

[0001] The present invention relates to a pouch.

Background Art

[0002] Conventionally, many products have been on the market in which cooked or semi-cooked liquid, viscous, or a mixture of liquid and solid contents are filled and sealed in a pouch made of a plastic laminate. In the pouch, a non-sealed portion where the laminates are not joined constitutes a storage portion for storing the contents. Also, a sealed portion where the laminates are joined seals the storage portion. The contents are, for example, cooked foods such as curry, stew, and soup. The contents are heated by a microwave oven or the like while being stored in the pouch.

[0003] When the contents stored in a sealed pouch are heated using a microwave oven, the moisture contained in the contents evaporates with heating, and the pressure in the storage portion increases. When the pressure in the storage portion of the pouch increases, there is a risk that the pouch will burst and the contents will scatter, soiling the inside of the microwave oven. In consideration of such problems, for example, Patent Document 1 proposes providing a steam venting mechanism in the pouch that automatically communicates the storage portion with the outside and vents the steam in the storage portion to the outside when the pressure in the storage portion increases. In Patent Document 1, the steam venting mechanism has an intermediate portion located between the upper side seal portion and the lower side seal portion of the pouch, and a non-sealed portion that is isolated from the storage portion by the intermediate portion and extends to reach the side edge of the pouch. When the pressure in the storage portion increases, the intermediate portion peels off, and the storage portion and the non-sealed portion communicate with each other. The steam in the storage portion is discharged to the outside through the portion where the storage portion and the non-sealed portion communicate.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0005] If the peeling of the seal part other than the intermediate part progresses before the intermediate part peels off and the accommodating part and the non-sealing part communicate with each other, there is a risk that the content will leak from the pouch.

[0006] An object of the present invention is to provide a pouch that can effectively solve such problems.

Means for Solving the Problems

[0007] Embodiments of the present disclosure relate to [1] to

[10] . [1] A self-supporting pouch, a front film and a back film, a lower film located between the front film and the back film in a state of being folded back at the folded-back part and located at the lower part of the pouch, a first side seal part located on the first side part of the pouch and joining the inner surface of the front film and the inner surface of the back film, a second side seal part located on the second side part facing the first side part of the pouch in a first direction and joining the inner surface of the front film and the inner surface of the back film, a first lower seal part joining the inner surface of the front film and the inner surface of the lower film and a second lower seal part joining the inner surface of the back film and the inner surface of the lower film, and including a lower seal part, an accommodating part surrounded by the first side seal part, the second side seal part, and the lower seal part and accommodating the content, a first non-sealing part located near the upper part of the pouch and separated from the accommodating part by the first side seal part, an upper seal part is formed by joining the inner surface of the front film and the inner surface of the back film at the upper part of the pouch, The first side seal portion includes an intermediate portion located between the accommodating portion and the first non-seal portion, an upper portion extending along the first side from the intermediate portion to the upper seal portion, and a lower portion extending along the first side from the intermediate portion to the lower seal portion. The pouch has a fifth dimension (S5), a seventh dimension (S7), an eighth dimension (S8), a tenth dimension (S10), an eleventh dimension (S11), and a first approximate volume (V1). The fifth dimension (S5) is the distance on the surface film between the lower end of the inner edge of the first lower seal portion and the folded-back portion. The seventh dimension (S7) is the distance on the surface film between the center point (C1) of the accommodating portion and the inner edge of the first side seal portion. The eighth dimension (S8) is calculated based on the following formula: S8 = ((S7) 2 - (S5) 2 ) 0.5 The tenth dimension (S10) is the distance on the surface film between the inner edge of the upper seal portion and the lower end of the inner edge of the intermediate portion. The eleventh dimension (S11) is the distance on the surface film between the lower end of the inner edge of the first lower seal portion and the lower end of the inner edge of the intermediate portion. The first approximate volume (V1) is calculated based on the following formula: V1 = 3.14 × S5 × S8 × S11 + S5 × S10 × S8 × 2 A first parameter (U1), which is the ratio of the eighth dimension (S8) [mm] to the first approximate volume (V1) [mm 3 is 7.000 × 10 -5 [mm -2 or more. The pouch.

[0008] [2] In the pouch according to [1], the first approximate volume (V1) may be 600,000 [mm 3 or more.

[0009] [3] In the pouch according to [1] or [2], the weight of the content accommodated in the accommodating portion may be 230 g or more.

[0010] [4] The pouch according to any one of [1] to [3] may have a first dimension (S1) of 145 mm or less. The first dimension (S1) is the distance on the surface film between the side edges of the first side portion and the side edges of the second side portion.

[0011] [5] The pouch according to any one of [1] to [4] may have a fourth dimension (S4) of 150 mm or less. The fourth dimension (S4) is the distance on the surface film between the inner edge of the upper seal portion and the lower end of the inner edge of the first lower seal portion.

[0012] [6] The pouch according to any one of [1] to [5] may have a sixth dimension (S6) of 61 mm or more and 69 mm or less. The sixth dimension (S6) is the distance on the surface film between the center point (C1) of the accommodating portion and the inner edge of the intermediate portion.

[0013] [7] The pouch according to any one of [1] to [6] may have a sixth dimension (S6). The sixth dimension (S6) is the distance on the surface film between the center point (C1) of the accommodating portion and the inner edge of the intermediate portion. A third parameter (U3), which is the ratio of the sixth dimension (S6) to the seventh dimension (S7), may be 0.95 or more and 1.05 or less.

[0014] [8] The pouch according to any one of [1] to [7] may have a second width (W2). The second width (W2) is the minimum value of the width of the first lower seal portion. A second parameter (U2), which is the ratio of the second width (W2) to the fifth dimension (S5), may be 0.20 or more.

[0015] [9] In the pouch according to any one of [1] to [8], the packaging material constituting the front film and the back film may include a biaxially stretched plastic film and a sealant film, the sealant film may contain polypropylene, and the polypropylene may contain block polypropylene.

[0016]

[10] In the pouch according to [9], the content of polypropylene in the sealant film may be 80% by mass or more.

Advantages of the Invention

[0017] According to the present invention, the progress of peeling of the seal portion other than the intermediate portion can be suppressed.

Brief Description of the Drawings

[0018]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Figure 6

Figure 7

Figure 8

Figure 9

Figure 10

Figure 11

Figure 12A

Figure 12B

Figure 12C

Figure 13

Figure 14

Figure 15

Figure 16

Mode for Carrying Out the Invention

[0019] With reference to the drawings, an embodiment of the present invention will be described. In the drawings attached to this specification, for the sake of easy illustration and understanding, the scale, the aspect ratio of the vertical and horizontal dimensions, etc. are appropriately changed and exaggerated from those of the actual object.

[0020] Regarding the terms used in this specification for specifying shapes, geometric conditions, and their degrees, such as terms like "parallel", "orthogonal", "identical", etc., and values of lengths and angles, etc., they are not bound by a strict meaning and are interpreted to include a range to the extent that similar functions can be expected.

[0021] In this specification, when there are two or more candidate upper limit values and two or more candidate lower limit values for a certain parameter, the numerical range of that parameter may be constituted by combining any one candidate upper limit value and any one candidate lower limit value. For example, consider the case where it is described that "Parameter B is, for example, A1 or more and may be A2 or more. Parameter B is, for example, A3 or less and may be A4 or less." In this case, the numerical range of Parameter B may be A1 or more and A3 or less, may be A1 or more and A4 or less, may be A2 or more and A3 or less, or may be A2 or more and A4 or less.

[0022] Pouch FIG. 1 is a front view showing the pouch 10 according to the present embodiment as viewed from the front side. The pouch 10 includes a storage portion 18 for storing contents. In FIG. 1, the pouch 10 in a state where no contents are stored is shown. The configuration of the pouch 10 will be described.

[0023] As shown in FIG. 1, the pouch 10 includes an upper portion 11, a lower portion 12, a first side portion 13, and a second side portion 14, and has a substantially rectangular outline in the front view. Names such as "upper portion", "lower portion", and "side portion", and terms such as "above" and "below" are merely relative representations of the positions and directions of the pouch 10 and its components when the side that can be positioned below when the pouch 10 is heated is defined as the lower portion. The posture of the pouch 10 is not limited by the names and terms in this specification.

[0024] The pouch 10 may be a gusseted pouch configured to be self-standing. The pouch 10 includes a front film 15 that forms the front surface, a back film 16 that forms the back surface, and a bottom film 17 located at the bottom 12. The bottom film 17 is disposed between the front film 15 and the back film 16 in a state of being folded back at the fold 17f. In FIG. 1, components such as the back film 16 and the bottom film 17 that are not visible when the pouch 10 is viewed from the front side are represented by dashed lines. Each film is constituted by a packaging material including at least one biaxially stretched plastic film and a sealant film.

[0025] The terms "front film", "back film", and "bottom film" merely demarcate each film according to the positional relationship. The method of providing the films when manufacturing the pouch 10 is not limited by the above terms. For example, the pouch 10 may be manufactured using a single film in which the front film 15, the back film 16, and the bottom film 17 are connected in series, or may be manufactured using two films in total, namely, a single film in which the front film 15 and the bottom film 17 are connected in series and a single back film 16, or may be manufactured using three films in total, namely, a single front film 15, a single back film 16, and a single bottom film 17.

[0026] The inner surfaces of the front film 15, the back film 16, and the bottom film 17 are joined to each other by a seal portion. In the plan view of the pouch 10 such as FIG. 1, the seal portion is hatched.

[0027] As long as the opposing films can be joined to each other, the method for forming the seal portion is not particularly limited. For example, the seal portion may be formed by melting the inner surfaces of the films 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 adhering the inner surfaces of the opposing films to each other using an adhesive or the like.

[0028] As shown in FIG. 1, the seal portion of the pouch 10 has a first side seal portion 30, a second side seal portion 50, and a lower seal portion 12a. The first side seal portion 30 is located on the first side portion 13 of the pouch 10. The second side seal portion 50 is located on the second side portion 14. The second side portion 14 faces the first side portion 13 in the first direction D1. The lower seal portion 12a is located on the lower portion 12. The lower seal portion 12a is connected to the first side seal portion 30 and the second side seal portion 50. The unsealed portion surrounded by the first side seal portion 30, the second side seal portion 50, and the lower seal portion 12a functions as a storage portion 18 for storing the content.

[0029] The first side seal portion 30 and the second side seal portion 50 join the inner surface of the front film 15 and the inner surface of the back film 16. The lower seal portion 12a includes a first lower seal portion 12a1 and a second lower seal portion 12a2. The first lower seal portion 12a1 joins the inner surface of the front film 15 and the inner surface of the lower film 17. The second lower seal portion 12a2 joins the inner surface of the back film 16 and the inner surface of the lower film 17.

[0030] In the pouch 10 in a state before the content is filled (a state in which the content is not stored), as shown in FIG. 1, the upper portion 11 of the pouch 10 is an opening 11b. After the content is stored in the pouch 10, an upper seal portion is formed at the opening 11b by joining the inner surface of the front film 15 and the inner surface of the back film 16 at the upper portion 11.

[0031] In addition to the non-sealing portion that functions as the accommodating portion 18, as shown in FIG. 1, the pouch 10 further includes a first non-sealing portion 45 separated from the accommodating portion 18 by the first side portion sealing portion 30. The non-sealing portion is a portion where there is a film whose opposing inner surfaces are not joined. The first non-sealing portion 45 is located closer to the upper portion 11 of the pouch 10. "Closer to the upper portion 11" means that the first non-sealing portion 45 is located on the upper portion 11 side of the center point C1. The center point C1 is a point on the surface film 15 that overlaps the center point of the accommodating portion 18 of the pouch 10 in a state where the content is not accommodated. The center point C1 is also referred to as the planar center point C1.

[0032] As shown in FIG. 1, the first non-sealing portion 45 extends so as to reach the first side edge 13x of the first side portion 13 of the pouch 10. In other words, the first non-sealing portion 45 overlaps the first side edge 13x and has an opening edge portion 46 that opens to the outside. The vapor generated in the accommodating portion 18 and flowing into the first non-sealing portion 45 can be discharged to the outside from the opening edge portion 46.

[0033] The first side portion sealing portion 30 is configured to define the first non-sealing portion 45. For example, as shown in FIG. 1, the first side portion sealing portion 30 has an upper portion 31, a lower portion 32, and an intermediate portion 33. The upper portion 31 extends along the first side portion 13 from the first non-sealing portion 45 toward the upper portion 11 of the pouch 10. The upper portion 31 may extend from the first non-sealing portion 45 to the upper sealing portion. The lower portion 32 extends along the first side portion 13 from the first non-sealing portion 45 toward the lower portion 12 of the pouch 10. The lower portion 32 may extend from the first non-sealing portion 45 to the lower sealing portion 12a. The intermediate portion 33 is located between the accommodating portion 18 and the first non-sealing portion 45. The intermediate portion 33 includes one end connected to the upper portion 31 and the other end connected to the lower portion 32. The upper portion 31 and the lower portion 32 may extend parallel to the second direction D2. For example, the inner edge 31x of the upper portion 31 and the inner edge 32x of the lower portion 32 may extend linearly in the second direction D2.

[0034] FIG. 2 is a cross-sectional view showing an example of the pouch 10 when viewed along line II-II in FIG. 1. When the pouch 10 is heated and steam is generated in the accommodating portion 18 to increase the pressure in the accommodating portion 18, the intermediate portion 33 is partially peeled off, and the accommodating portion 18 and the first non-sealing portion 45 communicate with each other. The steam flowing from the accommodating portion 18 into the first non-sealing portion 45 can be discharged to the outside from the opening edge portion 46. Thus, the intermediate portion 33 and the first non-sealing portion 45 function as a steam venting mechanism for discharging the steam in the accommodating portion 18 to the outside.

[0035] As shown in FIG. 1, a second non-sealing portion 65 may be formed between the second side edge 14x of the second side portion 14 and the second side portion sealing portion 50. In this case, the second non-sealing portion 65 may extend so as to reach the second side edge 14x. In other words, the second non-sealing portion 65 may overlap the second side edge 14x and have an opening edge portion 66 that opens to the outside.

[0036] The second side portion sealing portion 50 may have an upper portion 51, a lower portion 52, and an intermediate portion 53. The upper portion 51 extends along the second side portion 14 from the second non-sealing portion 65 toward the upper portion 11 of the pouch 10. The upper portion 51 may extend from the second non-sealing portion 65 to the upper sealing portion. The lower portion 52 extends along the second side portion 14 from the second non-sealing portion 65 toward the lower portion 12 of the pouch 10. The lower portion 52 may extend from the second non-sealing portion 65 to the lower sealing portion 12a. The intermediate portion 53 is located between the accommodating portion 18 and the second non-sealing portion 65. The intermediate portion 53 includes one end connected to the upper portion 51 and the other end connected to the lower portion 52. The upper portion 51 and the lower portion 52 may extend parallel to the second direction D2. For example, the inner edge 51x of the upper portion 51 and the inner edge 52x of the lower portion 52 may extend linearly in the second direction D2.

[0037] As shown in FIG. 1, the lower film 17 in contact with the first side edge 13x may have a notch formed therein. At the position of the notch, a seal portion 30b for joining the inner surface of the front film 15 and the inner surface of the back film 16 may be formed. Similarly, the lower film 17 in contact with the second side edge 14x may have a notch formed therein. At the position of the notch, a seal portion 50b for joining the inner surface of the front film 15 and the inner surface of the back film 16 may be formed.

[0038] As shown in FIG. 1, the pouch 10 may include an opening means 30a located in the upper portion 31. The opening means 30a penetrates through the front film 15 and the back film 16. The opening means 30a is a notch, a cut, or the like. The opening means 30a can serve as a starting point when the user tears the pouch 10. The opening means 30a extends from the first side edge 13x toward the accommodating portion 18.

[0039] As shown in FIG. 1, the pouch 10 may include an opening means 50a located in the second side seal portion 50. The opening means 50a penetrates through the front film 15 and the back film 16. The opening means 50a is a notch, a cut, or the like. Similar to the opening means 30a, the opening means 50a can serve as a starting point when the user tears the pouch 10. The opening means 50a extends from the second side edge 14x toward the accommodating portion 18. The opening means 50a may be formed in a portion of the second side seal portion 50 that faces the upper portion 31 in the first direction D1. For example, the opening means 50a may be formed in the upper portion 51.

[0040] FIG. 3 is a plan view showing the pouch 10 in a state where the contents are accommodated and the upper portion 11 is sealed. After the pouch 10 is filled with the contents through the opening 11b of the upper portion 11, the inner surface of the front film 15 and the inner surface of the back film 16 are joined at the upper portion 11. Thereby, the upper seal portion 11a is formed and the pouch 10 is sealed.

[0041] The contents contained in the pouch 10 are heated by a microwave oven. The contents may contain solid components. The solid components may contain components containing oil. The contents may contain liquid components. It is preferable that the contents have a low content rate of the components containing oil and the liquid components. The contents may be cooked foods that were conventionally stored in cans. Examples of the contents include bite-sized cartilage, meatballs, Iberian pork, petit baked tiramisu, Tosazu, chicken, wieners, fish cakes, simmered mackerel, simmered sweet potato, grilled salmon, grilled mackerel, simmered hijiki, simmered kelp, bacon potato salad, simmered soybeans, boiled quail eggs, pumpkin salad, stir-fried burdock, freeze-dried tofu, soy meat, mixed beans, etc.

[0042] One of the features of the pouch 10 according to the present embodiment is that the volume of the accommodating portion 18 is large. For example, the weight of the contents accommodated in the accommodating portion 18 of the pouch 10 according to the present embodiment is larger than the weight of the contents accommodated in the accommodating portion of an average pouch. The weight of the contents accommodated in the accommodating portion 18 is, for example, 230 g or more, may be 250 g or more, may be 260 g or more, or may be 270 g or more. The weight of the contents accommodated in the accommodating portion 18 is, for example, 300 g or less, may be 290 g or less, or may be 280 g or less.

[0043] When the pouch 10 is heated, steam is generated in the accommodating portion 18, the pouch 10 expands, and the pressure in the accommodating portion 18 increases. When the pressure in the accommodating portion 18 sufficiently increases, the peeling of the intermediate portion 33 progresses, and the accommodating portion 18 and the first non-sealing portion 45 communicate with each other. The larger the volume of the accommodating portion 18, the longer the time from the start of heating until the peeling of the intermediate portion 33 starts. The time from the start of heating until the peeling of the intermediate portion 33 starts is also referred to as the expansion period. The longer the expansion period, the higher the load applied to the sealing portions other than the intermediate portion 33, and the higher the risk that the peeling of the sealing portions other than the intermediate portion 33 progresses. If the sealing portions other than the intermediate portion 33 peel off, there is a risk that the contents will leak from the pouch 10.

[0044] In the present embodiment, by appropriately setting the dimensions of each part of the pouch 10, it is possible to expand the volume of the storage portion 18 while suppressing the progress of peeling of the seal portions other than the intermediate portion 33.

[0045] The dimensions of each part of the pouch 10 will be described. In the pouch 10 in a state where no content is stored, as shown in FIG. 1, the front film 15, the back film 16, and the bottom film 17 are each spreading parallel to each other. In other words, the pouch 10 in a state where no content is stored is not swollen. The dimensions of each part of the pouch 10 in a state where no content is stored are calculated as the distances on the surface of the front film 15.

[0046] In the state where no content is stored, as shown in FIG. 1, the pouch 10 has a first dimension S1 to a seventh dimension S7, a tenth dimension S10 to an eleventh dimension S11, a first width W1, a second width W2, a thirty-second width W32, and a forty-second width W42.

[0047] The first dimension S1 is the distance on the surface of the front film 15 between the first side edge 13x of the first side portion 13 and the second side edge 14x of the second side portion 14. The first dimension S1 is measured at a position where the distance between the first side edge 13x and the second side edge 14x in the first direction D1 is maximized. The first dimension S1 is, for example, 120 mm or more, may be 125 mm or more, or may be 130 mm or more. The first dimension S1 is, for example, 150 mm or less, may be 145 mm or less, or may be 140 mm or less.

[0048] The second dimension S2 is the distance on the surface of the front film 15 between the upper edge 11x of the upper portion 11 and the lower edge 12x of the lower portion 12. The second dimension S2 is measured at a position where the distance between the upper edge 11x and the lower edge 12x in the second direction D2 is maximized. The second dimension S2 is, for example, 140 mm or more, may be 145 mm or more, or may be 150 mm or more. The second dimension S2 is, for example, 170 mm or less, may be 165 mm or less, or may be 160 mm or less.

[0049] The third dimension S3 is the distance on the surface of the surface film 15 between the inner edge of the first side seal portion 30 and the inner edge of the second side seal portion 50. The third dimension S3 is measured along the first direction D1 at the intermediate position of the accommodating portion 18 in the second direction D2. In the example shown in FIG. 1, the third dimension S3 is measured between the inner edge 32x of the lower portion 32 and the inner edge 52x of the lower portion 52. The third dimension S3 is, for example, 115 mm or more, may be 117 mm or more, or may be 120 mm or more. The third dimension S3 is, for example, 135 mm or less, may be 132 mm or less, or may be 130 mm or less.

[0050] The fourth dimension S4 is the distance on the surface of the surface film 15 between the inner edge of the upper seal portion formed on the upper portion 11 and the inner edge 12x1 of the first lower seal portion 12a1 of the lower seal portion 12a. The fourth dimension S4 is measured at the position where the distance between the inner edge of the upper seal portion and the inner edge 12x1 of the first lower seal portion 12a1 in the second direction D2 is maximized. That is, the fourth dimension S4 is the distance on the surface of the surface film 15 between the inner edge of the upper seal portion 11a and the lower end of the inner edge 12x1 of the first lower seal portion 12a1. In the pouch 10 of FIG. 1, the position of the upper seal portion is determined in consideration of the upper seal portion 11a of the pouch 10 in the state where the contents are accommodated and sealed as shown in FIG. 3. The fourth dimension S4 is, for example, 125 mm or more, may be 130 mm or more, or may be 135 mm or more. The second dimension S2 is, for example, 155 mm or less, may be 150 mm or less, or may be 145 mm or less.

[0051] The fifth dimension S5 is the distance on the surface of the surface film 15 between the lower end of the inner edge 12x1 of the first lower seal portion 12a1 of the lower seal portion 12a and the folded portion 17f of the lower film 17. The fifth dimension S5 is measured along the second direction D2. The fifth dimension S5 is, for example, 27 mm or more, may be 30 mm or more, or may be 32 mm or more. The fifth dimension S5 is, for example, 43 mm or less, may be 40 mm or less, or may be 37 mm or less.

[0052] The sixth dimension S6 is the shortest distance on the surface of the surface film 15 between the planar center point C1 and the inner edge 33x of the intermediate portion 33. The straight line M3 in FIG. 1 connects the planar center point C1 and the inner edge 33x of the intermediate portion 33 at the shortest distance. The straight line M3 intersects the inner edge 33x at the point P1. The extension of the straight line M3 may intersect the opening edge portion 46. The sixth dimension S6 is, for example, 58 mm or more, may be 60 mm or more, may be 61 mm or more, or may be 62 mm or more. The sixth dimension S6 is, for example, 70 mm or less, may be 69 mm or less, may be 68 mm or less, or may be 66 mm or less.

[0053] The planar center point C1 is defined as the midpoint of the first line segment M1 passing through the intermediate position of the accommodating portion 18 in the second direction D2. The intermediate position of the accommodating portion 18 in the second direction D2 is defined by the midpoint of the second line segment M2 that linearly extends in the second direction D2 from the inner edge of the upper seal portion to the inner edge 12x1 of the first lower seal portion 12a1. The midpoint of the second line segment M2 is defined at the position where the length of the second line segment M2 is maximized. The first line segment M1 linearly extends in the first direction D1 from the inner edge of the first side seal portion 30 to the inner edge of the second side seal portion 50. In the example shown in FIG. 1, the first line segment M1 linearly extends in the first direction D1 from the inner edge 32x of the lower portion 32 of the first side seal portion 30 to the inner edge 52x of the lower portion 52 of the second side seal portion 50.

[0054] The seventh dimension S7 is the distance on the surface of the surface film 15 between the planar center point C1 and the inner edge of the first side seal portion 30. In the example shown in FIG. 1, the seventh dimension S7 is measured between the planar center point C1 and the inner edge 32x of the lower portion 32. The seventh dimension S7 is, for example, 58 mm or more, may be 60 mm or more, may be 61 mm or more, or may be 62 mm or more. The seventh dimension S7 is, for example, 70 mm or less, may be 69 mm or less, may be 68 mm or less, or may be 66 mm or less.

[0055] The straight line reaching the inner edge of the first side seal portion 30 from the plane center point C1 at the shortest distance intersects the inner edge 32x at the point P2. The seventh dimension S7 is the distance between the plane center point C1 and the point P2.

[0056] The seventh dimension S7 may be defined relative to the sixth dimension S6. The ratio S6 / S7 of the sixth dimension S6 to the seventh dimension S7 is also referred to as the third parameter U3. The third parameter U3 is, for example, 0.95 or more, may be 0.97 or more, and may be 0.99 or more. The third parameter U3 is, for example, 1.05 or less, may be 1.03 or less, and may be 1.01 or less.

[0057] The tenth dimension S10 is the distance on the surface of the surface film 15 between the inner edge of the upper seal portion and the lower end of the inner edge 33x of the intermediate portion 33. The lower end of the inner edge 33x of the intermediate portion 33 is, for example, the first inner edge 331 described later. The tenth dimension S10 is measured along the second direction D2. The lower end of the inner edge 33x of the intermediate portion 33 may function as a boundary where the swelling state changes in the pouch 10 in a heated and swollen state. The tenth dimension S10 is, for example, 30 mm or more, may be 35 mm or more, and may be 40 mm or more. The tenth dimension S10 is, for example, 55 mm or less, may be 50 mm or less, and may be 45 mm or less.

[0058] The eleventh dimension S11 is the distance on the surface of the surface film 15 between the lower end of the inner edge 12x1 of the first lower seal portion 12a1 of the lower seal portion 12a and the lower end of the inner edge 33x of the intermediate portion 33. The eleventh dimension S11 is measured along the second direction D2. The eleventh dimension S11 is, for example, 85 mm or more, may be 90 mm or more, and may be 95 mm or more. The eleventh dimension S11 is, for example, 115 mm or less, may be 110 mm or less, may be 105 mm or less, and may be 103 mm or less.

[0059] The first width W1 is the dimension of the upper seal portion 11a in the second direction D2. The second width W2 is the dimension of the first lower seal portion 12a1 in the second direction D2. The second width W2 is measured at the position where the dimension of the first lower seal portion 12a1 in the second direction D2 is minimized. The thirty-second width W32 is the dimension of the lower portion 32 of the first side seal portion 30 in the first direction D1. The forty-second width W42 is the dimension of the lower portion 52 of the second side seal portion 50 in the first direction D1. The thirty-second width W32 and the forty-second width W42 are measured at the position of the plane center point C1 in the second direction D2.

[0060] The first width W1, the second width W2, the thirty-second width W32, and the forty-second width W42 are, for example, 4 mm or more, may be 5 mm or more, and may be 6 mm or more. The first width W1, the second width W2, the thirty-second width W32, and the forty-second width W42 are, for example, 15 mm or less, may be 12 mm or less, and may be 10 mm or less.

[0061] The second width W2 may be defined relative to the fifth dimension S5. The ratio of the second width W2 to the fifth dimension S5, W2 / S5, is also referred to as the second parameter U2. The second parameter U2 is, for example, 0.20 or more, may be 0.22 or more, may be 0.25 or more, and may be 0.27 or more. By increasing the second parameter U2, it is possible to suppress the bottom surface of the pouch 10 from dropping to the lower edge 12x during heating. For this reason, it is possible to suppress the balance of the self-standing pouch 10 from being lost and the pouch 10 from falling over. Also, it is possible to suppress a person's hand from feeling heat when the heated pouch 10 is placed on the hand. The bottom surface of the pouch 10 during heating is constituted by a portion of the lower film 17 that is not joined to the front film 15 and the back film 16. The second parameter U2 is, for example, 0.60 or less, may be 0.50 or less, may be 0.40 or less, may be 0.35 or less, may be 0.33 or less, and may be 0.30 or less. If the second parameter U2 is too large, the area of the bottom surface of the pouch 10 during heating becomes small, and the volume for receiving the weight of the contents when the pouch 10 drops decreases. When the area of the bottom surface of the pouch 10 during heating is small, the load applied to the inner edge 12x1 of the first lower seal portion 12a1 and the inner edge 12x2 of the second lower seal portion 12a2 increases. For this reason, if the second parameter U2 is too large, the probability that the pouch 10 will burst when the pouch 10 drops increases. By the second parameter U2 being 0.60 or less, it is possible to suppress the pouch 10 from bursting when the pouch 10 drops.

[0062] The volume of the storage portion 18 of the pouch 10 is calculated in consideration of the three-dimensional shape of the pouch 10 in a state where the contents are stored and inflated. FIG. 4 is a perspective view showing an example of the pouch 10 in a state where the contents are stored. The reference sign C2 represents the center point of the storage portion 18 of the inflated pouch 10. The center point C2 is also referred to as the three-dimensional center point C2.

[0063] The puffed pouch 10 has an eighth dimension S8. The eighth dimension S8 is the distance between the three-dimensional center point C2 and the inner edge of the first side seal portion 30. In the example shown in FIG. 4, the eighth dimension S8 is the distance between the planar center point C1 and the point P2 on the inner edge 32x of the lower portion 32.

[0064] The eighth dimension S8 is approximately calculated based on the following formula. S8 = ((S7) 2 - (S5) 2 ) 0.5

[0065] The eighth dimension S8 is, for example, 45 mm or more, may be 47 mm or more, and may be 50 mm or more. The eighth dimension S8 is, for example, 60 mm or less, may be 57 mm or less, and may be 54 mm or less.

[0066] The cross-section of the storage portion 18 of the puffed pouch 10 at the position of the three-dimensional center point C2 is approximated by an elliptical first contour E1. FIG. 5 is a plan view showing the first contour E1. The first contour E1 has a major axis approximated by the eighth dimension S8 and a minor axis approximated by the fifth dimension S5. The major axis is the radius of the first contour E1 in the first direction D1. The minor axis is the radius of the first contour E1 in the third direction D3. The third direction D3 is orthogonal to the first direction D1 and is also orthogonal to the second direction D2. One-fourth of the length of the circumference of the elliptical first contour E1 is approximated by the seventh dimension S7.

[0067] FIG. 6 is a side view showing an example of the pouch 10 in a state where the contents are stored. The upper portion of the pouch 10 may have a contour that is close to a triangle in the side view. The upper portion of the pouch 10 is, for example, the portion of the pouch 10 that is located above the lower end of the inner edge 33x of the intermediate portion 33.

[0068] The volume of the puffed pouch 10 has a first approximate volume V1. The first approximate volume V1 is calculated as the sum of the volume of the first portion F1 and the volume of the second portion F2 shown in FIG. 7.

[0069] The first part F1 is an elliptical cylinder having a major radius of the eighth dimension S8, a minor radius of the fifth dimension S5, and a height of the eleventh dimension S11. The volume of the first part F1 is represented by 3.14 × S5 × S8 × S11. 3.14 is the value obtained by rounding the pi π to the third decimal place.

[0070] The second part F2 has a roof shape. The roof shape of the second part F2 has a triangular contour E2 in a side view and has a depth length of 2 × the eighth dimension S8. The length of the base of the triangle is 2 × the fifth dimension S5. The triangle has a height of the tenth dimension S10. The volume of the second part F2 is represented by S5 × S10 × S8 × 2.

[0071] The first approximate volume V1 is approximately calculated based on the following formula. V1 = 3.14 × S5 × S8 × S11 + S5 × S10 × S8 × 2

[0072] The first approximate volume V1 is, for example, 600000 [mm 3 or more, may be 650000 [mm 3 , may be 670000 [mm 3 , may be 700000 [mm 3 , may be 720000 [mm 3 or more. The larger the first approximate volume V1, the larger the weight of the contents accommodated in the accommodating portion 18 can be.

[0073] On the other hand, the larger the first approximate volume V1, the longer the expansion period, and the higher the risk of peeling of the seal portion other than the intermediate portion 33.

[0074] According to the present embodiment, by appropriately determining S8 / V1 [mm 3 , which is the ratio of the eighth dimension S8 [mm] to the first approximate volume V1 [mm -2 , it is possible to expand the volume of the accommodating portion 18 while suppressing the progress of peeling of the seal portion other than the intermediate portion 33. S8 / V1 is also referred to as the first parameter U1.

[0075] The first parameter U1 [mm -2 is, for example, 6.600×10 -5 [mm -2 or more, and may be 6.800×10 -5 [mm -2 or more, and may be 7.000×10 -5 [mm -2 or more, and may be 7.200×10 -5 [mm -2 or more. The first parameter U1 [mm -2 is, for example, 8.000×10 -5 [mm -2 or less, and may be 7.800×10 -5 [mm -2 or less, and may be 7.500×10 -5 [mm -2 or less.

[0076] The middle part 33 and the first non-sealing part 45 will be described in detail. FIG. 8 is a front view showing an enlarged view of the middle part 33 and the first non-sealing part 45.

[0077] The middle part 33 includes an inner edge 33x which is an edge located on the side of the accommodating part 18, and an outer edge which is an edge located on the side of the first non-sealing part 45. The inner edge 33x may include a first inner edge 331, a second inner edge 332, and a third inner edge 333, an inner edge first connecting part 336 connecting the first inner edge 331 and the second inner edge 332, and an inner edge second connecting part 337 connecting the second inner edge 332 and the third inner edge 333.

[0078] The first inner edge 331 extends from the inner edge first connecting part 336 toward the lower part 32. For example, the first inner edge 331 extends in a substantially first direction D1 toward the lower part 32. The angle formed by the direction in which the first inner edge 331 extends and the first direction D1 is, for example, 10° or less. As shown in FIG. 8, the first inner edge 331 may be connected to the inner edge 32x of the lower part 32.

[0079] The second inner edge 332 extends in a substantially second direction D2 from the first inner-edge connection portion 336 toward the upper portion 11 of the pouch 10. The angle formed by the direction in which the second inner edge 332 extends and the second direction D2 is, for example, 10° or less.

[0080] The third inner edge 333 extends from the second inner-edge connection portion 337 toward the side of the upper portion 31. For example, the third inner edge 333 extends toward the upper portion 31. The angle formed by the direction in which the third inner edge 333 extends and the first direction D1 is, for example, 30° or less. As shown in FIG. 8, the third inner edge 333 may be connected to the inner edge 31x of the upper portion 31.

[0081] As shown in FIG. 8, the direction in which the second inner edge 332 extends may be substantially orthogonal to the direction in which the first inner edge 331 extends. The angle θ1 formed by the direction in which the first inner edge 331 extends and the direction in which the second inner edge 332 extends is, for example, 85° or more and 95° or less.

[0082] The first inner-edge connection portion 336 is located closer to the lower portion 32. "Closer to the lower portion 32" means that the first inner-edge connection portion 336 is located on the lower portion 32 side of the center of the opening edge portion 46 in the second direction D2.

[0083] The second inner-edge connection portion 337 is located closer to the upper portion 31. "Closer to the upper portion 31" means that the second inner-edge connection portion 337 is located on the upper portion 31 side of the center of the opening edge portion 46 in the second direction D2.

[0084] In FIG. 8, reference numeral L12 represents the maximum value of the distance in the first direction D1 between the inner edge 32x of the lower portion 32 and the inner edge 33x of the intermediate portion 33. L12 is, for example, 5 mm or more, may be 7 mm or more, and may be 9 mm or more. L12 is, for example, 20 mm or less, may be 15 mm or less, and may be 12 mm or less. In the present embodiment, since the first non-sealing portion 45 extends so as to reach the first side edge 13x, it is easy to secure the area of the first non-sealing portion 45. For this reason, L12 can be made small. Thereby, the distance from the plane center point C1 to the inner edge 33x of the intermediate portion 33 can be increased. For this reason, it is possible to suppress the intermediate portion 33 from peeling off when a force due to an impact such as dropping is applied to the pouch 10. L12 is also referred to as the overhanging dimension of the intermediate portion 33.

[0085] The edge portion of the first non-sealing portion 45 will be described. The edge portion of the first non-sealing portion 45 includes an opening edge portion 46 located at the first side edge 13x of the first side portion 13, and an edge portion 48 on the sealing portion side defined by the lower edge of the upper portion 31, the upper edge of the lower portion 32, and the outer edge of the intermediate portion 33. As shown in FIG. 8, the edge portion 48 on the sealing portion side may include a first edge portion 481, a second edge portion 482, and a third edge portion 483, a first connecting portion 486 connecting the first edge portion 481 and the second edge portion 482, and a second connecting portion 487 connecting the second edge portion 482 and the third edge portion 483. The first connecting portion 486 faces the inner edge first connecting portion 336, and the second connecting portion 487 faces the inner edge second connecting portion 337. The first edge portion 481 corresponds to the first inner edge 331. For example, the first edge portion 481 extends at least partially parallel to the first inner edge 331. The second edge portion 482 corresponds to the second inner edge 332. For example, the second edge portion 482 extends at least partially parallel to the second inner edge 332. The third edge portion 483 may extend at least partially parallel to the third inner edge 333.

[0086] The first non-sealing portion 45 may extend to a position on the side of the second side portion 14 beyond the inner edge 32x of the lower side portion 32. In other words, a part of the edge of the first non-sealing portion 45 may be located on the side of the second side portion 14 beyond the inner edge 32x of the lower side portion 32. For example, the second edge portion 482 may be located on the side of the second side portion 14 beyond the inner edge 31x of the upper side portion 31. This makes it easier for vapor to flow from the accommodating portion 18 into the first non-sealing portion 45.

[0087] The first non-sealing portion 45 may extend to a position on the side of the second side portion 14 beyond the inner edge 31x of the upper side portion 31. For example, the second edge portion 482 may be located on the side of the second side portion 14 beyond the inner edge 31x of the upper side portion 31.

[0088] The first edge portion 481 extends from the first connecting portion 486 toward the opening edge portion 46. For example, the first edge portion 481 extends substantially in the first direction D1 toward the opening edge portion 46. The angle formed by the direction in which the first edge portion 481 extends and the first direction D1 is, for example, 10° or less. In the example shown in FIG. 8, the first edge portion 481 extends linearly until it reaches the opening edge portion 46.

[0089] The second edge portion 482 extends from the first connecting portion 486 toward the upper portion 11 of the pouch 10 substantially in the second direction D2. The angle formed by the direction in which the second edge portion 482 extends and the second direction D2 is, for example, 10° or less.

[0090] The third edge portion 483 extends from the second connecting portion 487 toward the opening edge portion 46. For example, the third edge portion 483 extends substantially in the first direction D1 toward the opening edge portion 46. The angle formed by the direction in which the third edge portion 483 extends and the first direction D1 is, for example, 10° or less. In the example shown in FIG. 5, the third edge portion 483 extends linearly until it reaches the opening edge portion 46.

[0091] As shown in FIG. 8, the direction in which the second edge portion 482 extends may be substantially orthogonal to the direction in which the first edge portion 481 extends. The angle θ2 formed by the direction in which the first edge portion 481 extends and the direction in which the second edge portion 482 extends is, for example, 85° or more and 95° or less.

[0092] In FIG. 8, reference numeral L11 represents the dimension of the opening edge portion 46 in the second direction D2. The dimension L11 is, for example, 4 mm or more, may be 10 mm or more, and may be 12 mm or more. The dimension L11 is, for example, 30 mm or less, may be 20 mm or less, and may be 18 mm or less.

[0093] The dimension of the first side seal portion 30 will be described.

[0094] In FIG. 8, reference numerals W31 and W32 respectively represent the width of the upper portion 31 and the width of the lower portion 32. The width W31 and the width W32 are, for example, 4 mm or more, and may be 6 mm or more. The width W31 and the width W32 are, for example, 15 mm or less, and may be 10 mm or less. The width W31 may be larger than the width W32.

[0095] In FIG. 8, reference numerals W33, W34, and W35 respectively represent the width of the portion extending along the first inner edge 331 of the middle portion 33, the width of the portion extending along the second inner edge 332 of the middle portion 33, and the width of the portion extending along the third inner edge 333 of the middle portion 33. Preferably, the width W33, the width W34, and the width W35 are smaller than the width W31 of the upper portion 31 and the width W32 of the lower portion 32. The width W33, the width W34, and the width W35 are, for example, 1 mm or more, and may be 2 mm or more. The width W33, the width W34, and the width W35 are, for example, 6 mm or less, and may be 5 mm or less. The width of each portion of the middle portion 33 is the dimension of the middle portion 33 in a direction orthogonal to the direction in which the inner edge of the middle portion 33 extends.

[0096] The middle portion 53 and the second non-seal portion 65 will be described in detail. FIG. 9 is a front view showing an enlarged view of the middle portion 53 and the second non-seal portion 65.

[0097] The edge of the second non-sealing portion 65 includes the above-described opening edge portion 66 located at the second side edge 14x, and the first edge portion 681, the second edge portion 682, and the third edge portion 683. The first edge portion 681 and the third edge portion 683 extend from the opening edge portion 66 toward the accommodating portion 18 side. The first edge portion 681 may extend in the same direction as the first edge portion 481 of the first non-sealing portion 45. Also, the third edge portion 683 may extend in the same direction as the third edge portion 483 of the first non-sealing portion 45. The second edge portion 682 includes a lower end connected to the first edge portion 681 and an upper end connected to the third edge portion 683, and extends in the second direction D2. The second non-sealing portion 65 having such a shape is formed simultaneously with the first non-sealing portion 45 by cutting one non-sealing portion, as disclosed in, for example, Japanese Patent Application Laid-Open No. 2016-74457. For example, when manufacturing a plurality of pouches 10 by cutting the surface film 15 and the back film 16 that extend along the conveyance direction and are partially joined to each other along the sealing portion and the non-sealing portion, one of the cut non-sealing portions becomes the first non-sealing portion 45 and the other becomes the second non-sealing portion 65. The second non-sealing portion 65 may be located on the side of the second side edge 14x rather than the inner edge 52x of the lower portion 52.

[0098] In FIG. 9, reference numerals W41, W42, and W43 represent the width of the upper portion 51, the width of the lower portion 52, and the width of the intermediate portion 53, respectively. In the example shown in FIG. 9, the width W41 of the upper portion 51 is larger than the width W42 of the lower portion 52 and the width W43 of the intermediate portion 53.

[0099] The layer configuration of the packaging material 70 constituting the surface film 15 and the back film 16 will be described. FIG. 10 is a cross-sectional view showing an example of the layer configuration of the packaging material 70.

[0100] The packaging material 70 shown in FIG. 10 includes at least a first biaxially stretched plastic film 71, a first adhesive layer 76, a second biaxially stretched plastic film 72, a second adhesive layer 77, and a sealant film 75 in this order. The first biaxially stretched plastic film 71 is located on the outer surface 70y side, and the sealant film 75 is located on the inner surface 70x side opposite to the outer surface 70y. The inner surface 70x faces the accommodating portion 18.

[0101] Each film constituting the packaging material 70, such as the first biaxially stretched plastic film 71, the second biaxially stretched plastic film 72, and the sealant film 75, and the packaging material 70 have a flow direction and a perpendicular direction. The flow direction is the direction in which the film flows when the film is formed, which is the so-called MD (Machine Direction). The perpendicular direction is the direction perpendicular to the flow direction, which is the so-called TD (Transverse Direction). In the pouch 10 shown in FIG. 1, the first direction D1 is the flow direction, and the second direction D2 is the perpendicular direction.

[0102] Each layer of the packaging material 70 will be described in detail respectively.

[0103] (The first biaxially stretched plastic film) The first biaxially stretched plastic film 71 is a film made of plastic and stretched in a predetermined two directions. The biaxially stretched plastic film is a plastic film intentionally stretched to improve the mechanical strength of the plastic film. The first biaxially stretched plastic film 71 functions as a base material layer for giving the packaging material 70 a predetermined strength. The stretching direction of the first biaxially stretched plastic film 71 is not particularly limited. For example, the first biaxially stretched plastic film 71 may be stretched in the first direction D1 and the second direction D2. The stretching ratio of the first biaxially stretched plastic film 71 is, for example, 1.05 times or more.

[0104] The first biaxially stretched plastic film 71 contains, for example, polyester as a main component. For example, the first biaxially stretched plastic film 71 contains 51% by mass or more of polyester. Examples of the polyester include polyethylene terephthalate (hereinafter also referred to as PET), polybutylene terephthalate (hereinafter also referred to as PBT), and the like. Note that the 51% by mass or more of polyester in the first biaxially stretched plastic film 71 may be composed of one type of polyester or may be composed of two or more types of polyester. The content of polyester in the first biaxially stretched plastic film 71 may be 70% by mass or more, may be 80% by mass or more, may be 90% by mass or more, or may be 95% by mass or more. For example, the content of PET in the first biaxially stretched plastic film 71 may be 70% by mass or more, may be 80% by mass or more, may be 90% by mass or more, or may be 95% by mass or more.

[0105] The thickness of the first biaxially stretched plastic film 71 is, for example, 8 μm or more, may be 9 μm or more, or may be 12 μm or more. The thickness of the first biaxially stretched plastic film 71 is, for example, 30 μm or less, may be 25 μm or less, or may be 20 μm or less. By setting the thickness of the first biaxially stretched plastic film 71 to 8 μm or more, the first biaxially stretched plastic film 71 has sufficient strength. By setting the thickness of the first biaxially stretched plastic film 71 to 30 μm or less, the first biaxially stretched plastic film 71 exhibits excellent formability. Therefore, the process of processing the packaging material 70 to manufacture the pouch 10 can be efficiently carried out.

[0106] (First adhesive layer) The first adhesive layer 76 contains an adhesive for adhering the first biaxially stretched plastic film 71 and the second biaxially stretched plastic film 72 by the dry lamination method. The adhesive constituting the first adhesive layer 76 is produced 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 contains a cured product formed by the reaction of the main agent and the solvent in the adhesive composition.

[0107] Examples of the adhesive include polyurethane. Polyurethane is a cured product formed by the reaction of a polyol as the main agent and an isocyanate compound as the curing agent. Examples of polyurethane include polyether polyurethane, polyester polyurethane, etc. Polyether polyurethane is a cured product formed by the reaction of a polyether polyol as the main agent and an isocyanate compound as the curing agent. Polyester polyurethane is a cured product formed by the reaction of a polyester polyol as the main agent and an isocyanate compound as the curing agent.

[0108] As the isocyanate compound, aromatic isocyanate compounds such as tolylene diisocyanate (TDI), 4,4'-diphenylmethane diisocyanate (MDI), xylylene diisocyanate (XDI), aliphatic isocyanate compounds such as hexamethylene diisocyanate (HDI), isophorone diisocyanate (IPDI), or adducts or polymers of the above various isocyanate compounds can be used.

[0109] The thickness of the first adhesive layer 76 is, for example, 2 μm or more, and may be 3 μm or more. The thickness of the first adhesive layer 76 is, for example, 6 μm or less, and may be 5 μm or less.

[0110] (The second biaxially stretched plastic film) The second biaxially stretched plastic film 72 is a plastic film stretched in a predetermined two directions, similar to the first biaxially stretched plastic film 71. The second biaxially stretched plastic film 72 also functions as a base material layer for imparting a predetermined strength to the packaging material 70, similar to the first biaxially stretched plastic film 71. The stretching direction of the second biaxially stretched plastic film 72 is not particularly limited, similar to the case of the first biaxially stretched plastic film 71. The stretching ratio of the second biaxially stretched plastic film 72 is, for example, 1.05 times or more.

[0111] The second biaxially stretched plastic film 72 may contain polyester as a main component. Examples of the polyester include PET, PBT, etc., similar to the case of the first biaxially stretched plastic film 71. The range of the polyester content in the second biaxially stretched plastic film 72 may be the same as that in the case of the first biaxially stretched plastic film 71. The thickness of the second biaxially stretched plastic film 72 containing polyester as a main component is, for example, 8 μm or more, may be 9 μm or more, and may be 12 μm or more. The thickness of the second biaxially stretched plastic film 72 containing polyester as a main component is, for example, 30 μm or less, may be 25 μm or less, and may be 20 μm or less.

[0112] The second biaxially stretched plastic film 72 may contain polyamide as a main component. For example, the second biaxially stretched plastic film 72 may contain 51% by mass or more of polyamide. Examples of polyamide include aliphatic polyamide or aromatic polyamide. Examples of aliphatic polyamide include nylons such as nylon-6, nylon-6,6, and copolymers of nylon 6 and nylon 6,6. Examples of aromatic polyamide include polymetaxylylene adipamide (MXD6). The content of polyamide in the second biaxially stretched plastic film 72 may be 70% by mass or more, 80% by mass or more, 90% by mass or more, or 95% by mass or more. The thickness of the second biaxially stretched plastic film 72 containing polyamide as a main component is, for example, 12 μm or more, and may be 15 μm or more. The thickness of the second biaxially stretched plastic film 72 containing polyamide as a main component is, for example, 30 μm or less, may be 25 μm or less, or may be 20 μm or less.

[0113] (Second Adhesive Layer) The second adhesive layer 77 contains an adhesive for adhering the second biaxially stretched plastic film 72 and the sealant film 75 by a dry lamination method. Examples of the adhesive of the second adhesive layer 77 include polyurethane as in the case of the first adhesive layer 76. In addition to the configurations, materials, and properties described below, the same configurations, materials, and properties as those of the first adhesive layer 76 can be adopted for the configuration, materials, and properties of the second adhesive layer 77.

[0114] The thickness of the second adhesive layer 77 is, for example, 2 μm or more, and may be 3 μm or more. The thickness of the second adhesive layer 77 is, for example, 6 μm or less, and may be 5 μm or less.

[0115] As is described above, as the isocyanate compound that constitutes the curing agent of the adhesive, there are aromatic isocyanate compounds and aliphatic isocyanate compounds. Aromatic isocyanate compounds elute components that cannot be used in food applications in a high-temperature environment such as heat sterilization. The second adhesive layer 77 is in contact with the sealant film 75. Therefore, when the second adhesive layer 77 contains an aromatic isocyanate compound, the components eluted from the aromatic isocyanate compound may adhere to the contents accommodated in the accommodating portion 18 in contact with the sealant film 75.

[0116] In consideration of such problems, preferably, as the adhesive that constitutes the second adhesive layer 77, a cured product formed by the reaction of a polyol as the main agent and an aliphatic isocyanate compound as the curing agent is used. Thereby, it is possible to suppress the adhesion of components that cannot be used in food applications due to the second adhesive layer 77 to the contents.

[0117] (Sealant film) The sealant film 75 will be described. The sealant film 75 constitutes the sealed portion of the pouch 10 by melting by heat sealing. The sealant film 75 may be an unstretched film. "Unstretched" is a concept that includes not only a film that is not stretched at all but also a film that is slightly stretched due to the tension applied during film formation.

[0118] The sealant film 75 may be single-layered. That is, the sealant film 75 may be composed of one layer. The sealant film 75 may be multi-layered. That is, the sealant film 75 may include a plurality of layers. Preferably, the sealant film 75 is single-layered.

[0119] Sterilization treatments such as boiling treatment and retort treatment are performed at high temperatures on the pouch 10 composed of the packaging material 70. The sealant film 75 has heat resistance to withstand these high-temperature treatments.

[0120] The melting point of the material constituting the sealant film 75 is preferably 150°C or higher, more preferably 160°C or higher. By increasing the melting point of the sealant film 75, it becomes possible to perform the retort treatment of the pouch 10 at a high temperature, and thus, the time required for the retort treatment can be shortened. The melting point of the material constituting the sealant film 75 is lower than the melting points of the biaxially stretched plastic films 71 and 72.

[0121] The sealant film 75 may contain propylene as a main component. For example, the sealant film 75 contains a first thermoplastic resin made of polypropylene. The content rate of propylene in the sealant film 75 is, for example, 90% by mass or more.

[0122] The first thermoplastic resin may be block polypropylene. Block polypropylene is a copolymer containing at least a homopolypropylene and a block elastomer. Examples of block polypropylene include propylene-ethylene block copolymers.

[0123] Block polypropylene may contain a polymer part (a) made of a propylene polymer and a polymer part (b) made of a polyethylene and an ethylene-propylene copolymer rubber component. Block polypropylene may contain a sea component made of a propylene polymer and an island component made of a polyethylene and an ethylene-propylene copolymer rubber component. The polymer part (a) and the sea component can contribute to increasing the heat resistance, rigidity, antiblocking property, and seal strength of the block polypropylene. The polymer part (b) and the island component can contribute to increasing the impact resistance of the block polypropylene. Therefore, by adjusting the ratio between the polymer part (a) and the polymer part (b) and the ratio between the sea component and the island component, the mechanical properties of the sealant film 75 containing block polypropylene can be adjusted.

[0124] The propylene polymer in the polymer part (a) is, for example, a propylene homopolymer having a melting point of 160 °C or higher. The propylene polymer may be a copolymer of propylene and a small amount (for example, 5 mol% or less) of an α-olefin as long as the melting point is 160 °C or higher. Examples of the α-olefin include ethylene, 1-butene, 1-hexene, and 1-octene.

[0125] In the polymer part (b), for example, in the polyethylene and ethylene-propylene copolymer rubber component, the content ratio of the structural unit derived from ethylene may be 20% by mass or more and 50% by mass or less. Thereby, for example, the impact resistance can be further improved. In the present disclosure, the content ratio of the structural unit can be measured by, for example, NMR. Note that among the polymer part (b), the ethylene-propylene copolymer rubber component corresponds to the block elastomer.

[0126] In the block polypropylene, it is preferable that the mass ratio of the polymer part (a) or the sea component composed of the propylene polymer is higher than the mass ratio of the polymer part (b) or the island component composed of the polyethylene and the ethylene-propylene copolymer rubber component.

[0127] In the block polypropylene, the mass ratio of the polymer part (a) or the sea component composed of the propylene polymer is preferably 51% by mass or more, more preferably 60% by mass or more, and still more preferably 70% by mass or more. The upper limit of the mass ratio of the polymer part (a) or the sea component composed of the propylene polymer is, for example, 90% by mass.

[0128] In the block polypropylene, the mass ratio of the polymer part (b) or the island component composed of the polyethylene and the ethylene-propylene copolymer rubber component is preferably 49% by mass or less, more preferably 40% by mass or less, and still more preferably 30% by mass or less. The lower limit of the mass ratio of the polymer part (b) or the island component composed of the polyethylene and the ethylene-propylene copolymer rubber component is, for example, 10% by mass.

[0129] The content of the first thermoplastic resin in the sealant film 75 is, for example, 70% by mass or more, and may be 75% by mass or more, 80% by mass or more, or 85% by mass or more. The content of the first thermoplastic resin in the sealant film 75 is, for example, 96% by mass or less, and may be 90% by mass or less.

[0130] In addition to the first thermoplastic resin, the sealant film 75 may contain a second thermoplastic resin. The second thermoplastic resin may be dispersed in the first thermoplastic resin. The second thermoplastic resin may be polyethylene. Polyethylene can contribute to enhancing the impact resistance of the sealant film 75. Examples of polyethylene include high-density polyethylene (HDPE), medium-density polyethylene (MDPE), low-density polyethylene (LDPE), linear low-density polyethylene (LLDPE), and the like.

[0131] The content of the second thermoplastic resin in the sealant film 75 is lower than the content of the first thermoplastic resin in the sealant film 75. The content of the second thermoplastic resin in the sealant film 75 is, for example, 2% by mass or more, and may be 4% by mass or more, 10% by mass or more, or 15% by mass or more. The content of the second thermoplastic resin in the sealant film 75 is, for example, 30% by mass or less, and may be 20% by mass or less, 15% by mass or less, or 10% by mass or less.

[0132] The sealant film 75 may contain a third thermoplastic resin in addition to the first thermoplastic resin. The sealant film 75 may contain a third thermoplastic resin in addition to the first and second thermoplastic resins. The third thermoplastic resin may be dispersed in the first thermoplastic resin. The third thermoplastic resin may be an elastomer. The elastomer may contribute to enhancing the impact resistance of the sealant film 75. Examples of the elastomer include propylene-ethylene copolymer (propylene-ethylene elastomer), ethylene-α-olefin copolymer (ethylene-α-olefin elastomer), and the like.

[0133] The content of the third thermoplastic resin in the sealant film 75 is lower than the content of the first thermoplastic resin in the sealant film 75. The content of the third thermoplastic resin in the sealant film 75 is, for example, 2% by mass or more, and may be 4% by mass or more. The content of the third thermoplastic resin in the sealant film 75 is, for example, 10% by mass or less, and may be 8% by mass or less.

[0134] The thickness of the sealant film 75 is, for example, 30 μm or more, may be 40 μm or more, may be 50 μm or more, and may be 60 μm or more. The thickness of the sealant film 75 is, for example, 100 μm or less, and may be 80 μm or less.

[0135] As types of the sealant film 75 containing the first thermoplastic resin made of block polypropylene, three types are conceivable.

[0136] The first type of sealant film 75 is a single-layer unoriented polypropylene film that contains a first thermoplastic resin having the above-described content and a second thermoplastic resin having the above-described content, but does not contain a third thermoplastic resin having the above-described content. The first type of sealant film 75 has high tensile elongation and impact resistance. The first type of sealant film 75 preferably further has the characteristic of low hot seal strength. Thereby, it is possible to suppress the pressure in the accommodation portion from becoming excessive when the pouch is heated. Thereby, it is possible to suppress damage to the packaging material.

[0137] The second type of sealant film 75 is a single-layer unoriented polypropylene film that contains a first thermoplastic resin having the above-described content, a second thermoplastic resin having the above-described content, and a third thermoplastic resin having the above-described content. The second type of sealant film 75 has a high tensile elastic modulus. By using the second type of sealant film 75, the tearability when opening the pouch can be enhanced.

[0138] In the present embodiment, preferably, the packaging material 70 includes the first type of sealant film 75.

[0139] The first type of sealant film 75 will be described in detail. The content of the first thermoplastic resin in the first type of sealant film 75 is, for example, 70% by mass or more, and may be 75% by mass or more. The content of the first thermoplastic resin is, for example, 85% by mass or less, and may be 80% by mass or less.

[0140] In the first type of sealant film 75, the polyethylene of the second thermoplastic resin is 0.90 g / cm 3 or more and 0.93 g / cm 3It may have the following density. The polyethylene may be linear low density polyethylene. The content of the second thermoplastic resin in the sealant film 75 is, for example, 15% by mass or more, and may be 20% by mass or more. The content of the second thermoplastic resin in the sealant film 75 is, for example, 30% by mass or less, and may be 25% by mass or less.

[0141] The tensile elongation at 23 °C of the first type of sealant film 75 in the machine direction (MD) is, for example, 800% or more, and may be 900% or more, 1000% or more, or 1100% or more. The product of the tensile elongation (%) and the thickness (μm) of the first type of sealant film 75 in the machine direction (MD) is, for example, 45000 or more, and may be 50000 or more, 55000 or more, or 60000 or more. The tensile elongation at 23 °C of the first type of sealant film 75 in the transverse direction (TD) is, for example, 1050% or more, and may be 1100% or more. The product of the tensile elongation (%) and the thickness (μm) of the first type of sealant film 75 in the transverse direction (TD) is, for example, 53000 or more, and may be 60000 or more. Since the sealant film 75 has a high tensile elongation, it is possible to prevent the pouch 10 from bursting due to an impact during dropping or the like.

[0142] The Young's modulus at 23 °C of the first type of sealant film 75 in the machine direction (MD) is, for example, 670 MPa or less, and may be 650 MPa or less. The product of the Young's modulus (MPa) and the thickness (μm) of the first type of sealant film 75 in the machine direction (MD) is, for example, 38000 or less, and may be 35000 or less. The Young's modulus at 23 °C of the first type of sealant film 75 in the transverse direction (TD) is, for example, 550 MPa or less, and may be 500 MPa or less. The product of the Young's modulus (MPa) and the thickness (μm) of the first type of sealant film 75 in the transverse direction (TD) is, for example, 30000 or less, and may be 25000 or less.

[0143] The thickness of the first type of sealant film 75 is, for example, 30 μm or more, and may be 50 μm or more, 55 μm or more, or 60 μm or more. The thickness of the first type of sealant film 75 is, for example, 100 μm or less, and may be 80 μm or less.

[0144] The second type of sealant film 75 will be described in detail. The content of the first thermoplastic resin in the second type of sealant film 75 is, for example, 80% by mass or more, and may be 85% by mass or more. The content of the first thermoplastic resin is, for example, 96% by mass or less, and may be 90% by mass or less.

[0145] In the second type of sealant film 75, the polyethylene of the second thermoplastic resin is 0.94 g / cm 3 or more and 0.97 g / cm 3 or less. The content of the second thermoplastic resin in the sealant film 75 is, for example, 2% by mass or more, and may be 4% by mass or more. The content of the second thermoplastic resin in the sealant film 75 is, for example, 10% by mass or less, and may be 8% by mass or less.

[0146] In the second type of sealant film 75, the elastomer of the third thermoplastic resin may be an ethylene·α-olefin copolymer elastomer. The ethylene·α-olefin copolymer elastomer may contain an α-olefin having 3 to 10 carbon atoms and ethylene. The ethylene·α-olefin copolymer elastomer is 0.86 g / cm 3 or more and 0.90 g / cm 3 or less. The content of the third thermoplastic resin in the sealant film 75 is, for example, 2% by mass or more, and may be 4% by mass or more. The content of the third thermoplastic resin in the sealant film 75 is, for example, 10% by mass or less, and may be 8% by mass or less.

[0147] The Young's modulus at 23°C of the second type of sealant film 75 in the flow direction (MD) is, for example, 500 MPa or more, and may be 600 MPa or more, 650 MPa or more, or 700 MPa or more. The product of the Young's modulus (MPa) and the thickness (μm) of the second type of sealant film 75 in the flow direction (MD) is, for example, 35000 or more, and may be 38000 or more, 45000 or more. The Young's modulus at 23°C of the second type of sealant film 75 in the transverse direction (TD) is, for example, 450 MPa or more, and may be 500 MPa or more, 550 MPa or more, or 600 MPa or more. The product of the Young's modulus (MPa) and the thickness (μm) of the second type of sealant film 75 in the transverse direction (TD) is, for example, 25000 or more, and may be 30000 or more, 35000 or more, or 38000 or more.

[0148] The tensile elongation at 23°C of the second type of sealant film 75 in the flow direction (MD) is, for example, 1100% or less, and may be 1000% or less, less than 1000%, 900% or less, or 800% or less. The product of the tensile elongation (%) and the thickness (μm) of the second type of sealant film 75 in the flow direction (MD) is, for example, 55000 or less, and may be 50000 or less. The tensile elongation at 23°C of the second type of sealant film 75 in the transverse direction (TD) is, for example, 1200% or less, and may be 1100% or less, less than 1100%, 1000% or less, or 900% or less. The product of the tensile elongation (%) and the thickness (μm) of the second type of sealant film 75 in the transverse direction (TD) is, for example, 60000 or less, and may be 55000 or less.

[0149] The thickness of the second type of sealant film 75 is, for example, 55 μm or more, and may be 60 μm or more. The thickness of the second type of sealant film 75 is, for example, 80 μm or less, and may be 70 μm or less.

[0150] The tensile elastic modulus and tensile elongation of the sealant film 75 are measured in accordance with JIS K7127. As the measuring instrument, a tensile tester RTC-1310A manufactured by Orientec Co., Ltd. is used. As the test piece, a rectangular film obtained by cutting the sealant film 75 into a film with a width of 15 mm and a length of 150 mm is used. The interval at the start of measurement between a pair of chucks holding the test piece is 100 mm, and the tensile speed is 300 mm / min. Note that the length of the test piece can be adjusted as long as the test piece can be gripped by a pair of chucks. In the present application, unless otherwise specified, the environmental temperature during the test is 25°C and the relative humidity is 50%. The value obtained by averaging the measured values of five test pieces is used as the tensile elastic modulus and tensile elongation of the present application.

[0151] The third type of sealant film 75 is a single-layer unoriented polypropylene film containing a first thermoplastic resin, a second thermoplastic resin, and a third thermoplastic resin. The third type of sealant film 75 has a low dimensional change rate. The dimensional change rate of the sealant film can be read from the expansion rate measured by the tensile mode of thermomechanical analysis. Thermomechanical analysis is also referred to as TMA.

[0152] The expansion rate of the sealant film 75 is measured using a sample cut out from the sealant film 75 after retort treatment. The method of retort treatment is the spray type. The temperature and time of retort treatment are 121°C and 30 minutes.

[0153] In the measurement of the expansion rate, a tensile force is applied to a sample of the sealant film 75 clamped by chucks. Subsequently, while changing the environment around the sample in the order of the first temperature reduction process, the first temperature increase process, and the second temperature reduction process, the dimensional change of the sample is measured. The expansion rate is calculated based on the dimensions of the sample in the first temperature increase process. The specific conditions are as follows. Length of the sample between chucks: 10 mm Width of the sample: 5 mm Tensile force: 30 mN First cooling process: After setting the temperature to decrease from 25°C to 0°C at 10°C per minute, the set temperature of 0°C was maintained for 15 minutes. First heating process: After setting the temperature to increase from 0°C to 135°C at 10°C per minute, the set temperature of 135°C was maintained for 5 minutes. Second cooling process: After setting the temperature to decrease from 135°C to 0°C at 10°C per minute, the set temperature of 0°C was maintained for 15 minutes.

[0154] The expansion rate ΔL is calculated by the following formula. The unit of the expansion rate ΔL is %. ΔL = {(L2 - L1) / L1} × 100 L1 is the distance between the chucks when the set temperature is 20°C in the first heating process. L2 is the distance between the chucks at any temperature in the first cooling process and the first heating process. The expansion rate at a temperature of 125°C in the first heating process is referred to as the dimensional change rate. An example of the measurement results of the expansion rate of the sample in the first cooling process and the first heating process in the tensile mode of TMA is shown in FIG. 11. The horizontal axis of FIG.  11 is the temperature around the sample. The vertical axis of FIG. 11 is the expansion rate based on the distance between the chucks when the temperature is 20°C in the first heating process. FIG. 11 shows the results of measuring the expansion rate of the sealant film 75 using two samples n1 and n2. The average value of the dimensional change rate read from the expansion rates of the two samples n1 and n2 is adopted as the dimensional change rate of the sealant film 75.

[0155] The dimensional change rate of the sealant film 75 in the flow direction is, for example, 5.4% or less, may be 5.0% or less, may be 4.5% or less, may be 4.2% or less, may be 4.0% or less, may be 3.8% or less, or may be 3.5% or less. When the dimensional change rate of the sealant film 75 in the flow direction is 5.0% or less, the peeling of the isolation seal portion 20b can appropriately reach the unsealed portion 20a when the pouch 10 is heated. The dimensional change rate of the sealant film 75 in the flow direction is, for example, 2.5% or more, may be 2.7% or more, may be 3.0% or more, or may be 3.2% or more.

[0156] The third type of sealant film 75 preferably has a low complex elastic modulus. The complex elastic modulus of the sealant film 75 is measured by the nanoindentation method. Specifically, the complex elastic modulus of the sealant film 75 is measured by pressing the indenter of the nanoindenter into the cross-section of the sealant film 75 of the packaging material 70.

[0157] The complex elastic modulus of the sealant film 75 of the packaging material 70 constituting the pouch 10 is measured using the packaging material 70 cut out from the pouch 10 after the retort treatment. The pouch 10 is produced by folding a single piece of packaging material 70 in half so that the sealant films 75 face each other and performing heat welding along the outer edges of the folded packaging material 70. The pouch 10 is filled with 100 mL of water and the retort treatment is carried out with the pouch 10 sealed. The retort treatment method is a hot water type. The temperature and time of the retort treatment are 121 °C and 30 minutes.

[0158] The indenter is pressed into the central portion in the thickness direction of the portion where the cross-section of the sealant film 75 is exposed.

[0159] The measurement conditions are as follows. As the indenter of the nanoindenter, a Berkovich indenter (triangular pyramid indenter) is used. The indenter is pushed into the sealant film 75 from the cross-section of the sealant film 75 to a load of 30 μN over 3 seconds, held in that state for 5 seconds, and then unloaded over 3 seconds. Based on the load and displacement during the indenter being pushed in, the maximum load P max and the load-displacement curve are obtained. Based on the trace formed on the sealant film 75 where the indenter is pushed in, the contact projected area A p at the maximum depth is measured. The trace where the indenter is pushed in is a depression also referred to as an indentation. From the load-displacement curve, the complex elastic modulus is calculated by the following formula (1).

[0160]

Equation

[0161] The measurement is carried out in a room temperature (23 °C) environment. The measurement is carried out at five or more locations on the same cross-section, and the complex elastic modulus is described as the arithmetic mean value of the values measured at five locations with good reproducibility respectively.

[0162] The complex elastic modulus of the sealant film 75 can be adjusted by the mass ratio of the polymer part (b) or the island component in the block polypropylene when the sealant film 75 contains block polypropylene. For example, the higher the mass ratio of the polymer part (b) or the island component, the lower the complex elastic modulus of the sealant film 75.

[0163] The complex elastic modulus of the sealant film 75 can also be adjusted by the content of a second thermoplastic resin such as polyethylene or the content of a third thermoplastic resin such as an elastomer when the sealant film 75 contains block polypropylene. For example, the higher the content of the second thermoplastic resin or the third thermoplastic resin, the lower the complex elastic modulus of the sealant film 75. For example, the lower the content of the second thermoplastic resin or the third thermoplastic resin, the higher the complex elastic modulus of the sealant film 75.

[0164] The complex elastic modulus of the sealant film 75 is, for example, 800 MPa or less, may be 750 MPa or less, and may be 700 MPa or less. When the complex elastic modulus of the sealant film 75 is 800 MPa or less, the packaging material 70 can have impact resistance even when the thickness of the sealant film 75 is small. For example, even when the thickness of the sealant film 75 is 50 μm or less, the pouch 10 is suppressed from being torn by an impact such as a drop.

[0165] In the third type of sealant film 75, the content of the polymer part (a) or the sea component composed of a propylene polymer is, for example, 30% by mass or more, may be 35% by mass or more, and may be 40% by mass or more. In the third type of sealant film 75, the content of the polymer part (a) or the sea component composed of a propylene polymer is, for example, 55% by mass or less, may be 50% by mass or less, and may be 45% by mass or less.

[0166] In the third type of sealant film 75, the content of the polymer part (b) or the island component composed of polyethylene and an ethylene-propylene copolymer rubber component is, for example, 14% by mass or less, may be 12% by mass or less, and may be 11% by mass or less. In the sealant layer 44, the content of the polymer part (b) or the island component composed of polyethylene and an ethylene-propylene copolymer rubber component is, for example, 7% by mass or more, may be 8% by mass or more, and may be 9% by mass or more.

[0167] In the third type of sealant film 75, the content rate of the first thermoplastic resin may be higher than the total of the content of the second thermoplastic resin and the content rate of the third thermoplastic resin. The content rate of the first thermoplastic resin in the third type of sealant film 75 is, for example, 51% by mass or more, may be 55% by mass or more, and may be 60% by mass or more. The content rate of the first thermoplastic resin in the third type of sealant film 75 is, for example, 70% by mass or less, may be 65% by mass or less, may be 60% by mass or less, and may be 55% by mass or less.

[0168] The content rate of the second thermoplastic resin in the third type of sealant film 75 is, for example, 30% by mass or more, and may be 35% by mass or more. The content rate of the second thermoplastic resin in the third type of sealant film 75 is, for example, 50% by mass or less, and may be 45% by mass or less.

[0169] The third thermoplastic resin in the third type of sealant film 75 preferably contains an elastomer made of a propylene-ethylene random copolymer. By using a propylene-ethylene random copolymer, it is possible to improve the drop strength of the pouch 10 while suppressing a decrease in the hot seal strength of the packaging material 70.

[0170] The content rate of the third thermoplastic resin in the third type of sealant film 75 is, for example, 5% by mass or more, may be 7% by mass or more, and may be 9% by mass or more. The content rate of the third thermoplastic resin in the third type of sealant film 75 is, for example, 20% by mass or less, may be 16% by mass or less, and may be 12% by mass or less.

[0171] The thickness of the third type of sealant film 75 is, for example, 30 μm or more, may be 40 μm or more, and may be 50 μm or more. The thickness of the third type of sealant film 75 is, for example, 70 μm or less, may be 60 μm or less, and may be 50 μm or less.

[0172] As shown in FIG. 10, the packaging material 70 may further include a printing layer 81. The printing layer 81 is a layer provided on the packaging material 70 to show product information or impart aesthetic feeling to the packaging material 70. The printing layer 81 is provided, for example, on the first biaxially stretched plastic film 71. The printing layer 81 represents characters, numbers, symbols, figures, patterns, etc. The printing layer 81 includes, for example, a coloring material such as ink and a binder resin. As the ink for gravure printing, Finart manufactured by DIC Graphics Corporation can be used.

[0173] FIGS. 12A and 12B are cross-sectional views showing other examples of the layer structure of the packaging material 70. As shown in FIGS. 12A and 12B, the packaging material 70 may include a transparent vapor deposition layer 82 located between the first biaxially stretched plastic film 71 and the second biaxially stretched plastic film 72. The packaging material 70 may include a transparent gas barrier coating film 83 located on the surface of the transparent vapor deposition layer 82. As shown in FIG. 12A, the transparent vapor deposition layer 82 may be provided on the inner surface of the first biaxially stretched plastic film 71. As shown in FIG. 12B, the transparent vapor deposition layer 82 may be provided on the outer surface of the second biaxially stretched plastic film 72.

[0174] 〔Transparent vapor deposition layer〕 The transparent vapor deposition layer 82 may be composed of a single vapor deposition layer or may include two or more vapor deposition layers. When the transparent vapor deposition layer 82 includes two or more vapor deposition layers, each layer may have the same composition or different compositions. Examples of the method for forming the transparent vapor deposition layer 82 include physical vapor deposition methods (Physical Vapor Deposition method, PVD method) such as vacuum vapor deposition method, sputtering method, and ion plating method, or chemical vapor deposition methods (Chemical Vapor Deposition method, CVD method) such as plasma chemical vapor deposition method, thermal chemical vapor deposition method, and photo chemical vapor deposition method. Specifically, a vapor deposition layer can be formed on a film-forming roller using a roller-type vapor deposition film forming apparatus.

[0175] The transparent vapor deposition layer 82 is composed of an inorganic material having transparency. Examples of the inorganic material include metal oxides and inorganic oxides. Examples of the metal oxide include oxides of metals such as aluminum (Al), magnesium (Mg), calcium (Ca), potassium (K), tin (Sn), sodium (Na), boron (B), titanium (Ti), lead (Pb), zirconium (Zr), and yttrium (Y). Examples of the inorganic oxide include oxide of silicon (Si). As the inorganic material constituting the transparent vapor deposition layer, aluminum oxide (aluminum oxide) or silicon oxide is preferable.

[0176] The thickness of the transparent vapor deposition layer 82 is, for example, 20 Å or more, and may be 30 Å or more, 40 Å or more, 50 Å or more, 60 Å or more, or 70 Å or more. The thickness of the transparent vapor deposition layer 82 is, for example, 150 Å or less, and may be 130 Å or less, 120 Å or less, or 110 Å or less.

[0177] 〔Gas barrier coating film〕 The transparent gas barrier coating film 83 has transparency. The transparent gas barrier coating film 83 can suppress permeation of oxygen gas, water vapor, etc. The transparent gas barrier coating film 83 contains at least one or more alkoxides represented by the general formula R 1 n M(OR 2 ) m (wherein, in the formula, R 1 , R 2 represent organic groups having 1 to 8 carbon atoms, M represents a metal atom, n represents an integer of 0 or more, m represents an integer of 1 or more, and n + m represents the valence of M.) and the above-mentioned polyvinyl alcohol-based resin and / or ethylene-vinyl alcohol copolymer, and is further obtained from a transparent gas barrier composition that undergoes polycondensation by the sol-gel method in the presence of a sol-gel method catalyst, an acid, water, and an organic solvent.

[0178] The above general formula R 1 n M(OR2 ) m As the alkoxide represented by the formula, at least one or more of a partial hydrolyzate of the alkoxide and a condensate of the hydrolysis of the alkoxide can be used. Further, as the partial hydrolyzate of the alkoxide, it is not necessary that all of the alkoxy groups are hydrolyzed, and those in which one or more are hydrolyzed, and mixtures thereof may be used. As the condensate of the hydrolysis of the alkoxide, those having a dimer or more of the partial hydrolyzed alkoxide, specifically, those having a dimer to hexamer are used.

[0179] In the above general formula R 1 n M(OR 2 ) m In the alkoxide represented by the formula, as the metal atom represented by M, silicon, zirconium, titanium, aluminum, and others can be used. Preferred metals include, for example, silicon, titanium, and the like. Further, in the present embodiment, as the method of using the alkoxide, it is also possible to mix and use the alkoxides of a single or two or more different metal atoms in the same solution.

[0180] In the above general formula R 1 n M(OR 2 ) m In the alkoxide represented by the formula, specific examples of the organic group represented by R 1 include, for example, alkyl groups such as methyl group, ethyl group, n-propyl group, i-propyl group, n-butyl group, i-butyl group, sec-butyl group, t-butyl group, n-hexyl group, n-octyl group, and others. Further, in the above general formula R 1 n M(OR 2 ) m In the alkoxide represented by the formula, specific examples of the organic group represented by R 2 include, for example, methyl group, ethyl group, n-propyl group, i-propyl group, n-butyl group, sec-butyl group, and others. Note that these alkyl groups in the same molecule may be the same or different.

[0181] When preparing the above transparent gas barrier composition, for example, a silane coupling agent or the like may be added. As the above silane coupling agent, a known organoalkoxysilane containing an organic reactive group can be used. In particular, an organoalkoxysilane having an epoxy group is preferably used. Specifically, for example, γ-glycidoxypropyltrimethoxysilane, γ-glycidoxypropylmethyldiethoxysilane, or β-(3,4-epoxycyclohexyl)ethyltrimethoxysilane can be used. Such silane coupling agents may be used alone or in combination of two or more.

[0182] The thickness of the transparent gas barrier coating film 83 is, for example, 100 nm or more, and may be 125 nm or more, 150 nm or more, or 200 nm or more. Thereby, stable gas barrier properties can be obtained. The thickness of the transparent gas barrier coating film 83 is, for example, 500 nm or less, and may be 450 nm or less, 400 nm or less, or 300 nm or less.

[0183] As shown in FIGS. 10, 12A, and 12B, the biaxially stretched plastic film included in the packaging material 70 may be only two sheets. Specific examples of the packaging material 70 in this case are shown below. " / " is used as a notation indicating the boundary between layers when listing layers. The layers arranged from the outside to the inside of the pouch are described from left to right. Biaxially stretched PET film / Printing layer / Adhesive layer / Biaxially stretched nylon film / Adhesive layer / Sealing film Biaxially stretched PET film / Printing layer / Adhesive layer / Biaxially stretched PET film / Adhesive layer / Sealing film Biaxially stretched PET film / Transparent vapor deposition layer / Transparent gas barrier coating film / Printing layer / Adhesive layer / Biaxially stretched nylon film / Adhesive layer / Sealing film Biaxially stretched PET film / Transparent vapor deposition layer / Transparent gas barrier coating film / Printing layer / Adhesive layer / Biaxially stretched PET film / Adhesive layer / Sealing film Biaxially oriented PET film / Printing layer / Adhesive layer / Transparent gas barrier coating film / Transparent vapor deposition layer / Biaxially oriented PET film / Adhesive layer / Sealing film

[0184] The thickness of the packaging material 70 containing only two biaxially oriented plastic films is, for example, 80 μm or more, may be 90 μm or more, and may be 100 μm or more. The thickness of the packaging material 70 containing only two biaxially oriented plastic films is, for example, 130 μm or less, and may be 120 μm or less.

[0185] FIG. 12C is a cross-sectional view showing another example of the layer structure of the packaging material 70. As shown in FIG. 12C, the packaging material 70 may include a third biaxially oriented plastic film 73 in addition to the first biaxially oriented plastic film 71 and the second biaxially oriented plastic film 72. That is, the packaging material 70 may include three biaxially oriented plastic films. Although not shown, the packaging material 70 may include four or more biaxially oriented plastic films.

[0186] The third biaxially oriented plastic film 73 is a plastic film stretched in a predetermined two directions, similar to the first biaxially oriented plastic film 71. The third biaxially oriented plastic film 73 also functions as a base material layer for giving the packaging material 70 a predetermined strength, similar to the first biaxially oriented plastic film 71. The third biaxially oriented plastic film 73 may contain polyester as a main component. The third biaxially oriented plastic film 73 may be located between the second biaxially oriented plastic film 72 and the sealing film 75. The second adhesive layer 77 may bond the second biaxially oriented plastic film 72 and the third biaxially oriented plastic film 73 by a dry lamination method.

[0187] The packaging material 70 may include a third adhesive layer 78 positioned between a third biaxially stretched plastic film 73 and a sealant film 75. The third adhesive layer 78 includes an adhesive for adhering the third biaxially stretched plastic film 73 and the sealant film 75 by a dry lamination method.

[0188] As shown in FIG. 12C, the packaging material 70 including three biaxially stretched plastic films may include a transparent vapor deposition layer 82 and a transparent gas barrier coating film 83. The transparent vapor deposition layer 82 may be provided on the inner surface of the first biaxially stretched plastic film 71. Although not shown, the transparent vapor deposition layer 82 may be provided on the outer surface or the inner surface of the second biaxially stretched plastic film 72.

[0189] The packaging material constituting the lower film 17 may include at least a first biaxially stretched plastic film, a first adhesive layer, a second biaxially stretched plastic film, a second adhesive layer, and a sealant film in this order, similar to the packaging material 70 shown in FIG. 10, FIG. 12A, or FIG. 12B. The packaging material constituting the lower film 17 may include three biaxially stretched plastic films, similar to the packaging material 70 shown in FIG. 12C. The packaging material constituting the lower film 17 may be the same as or different from the packaging material 70 constituting the front film 15 and the back film 16.

[0190] Method for manufacturing a pouch A method for manufacturing the pouch 10 using the packaging material 70 will be described. First, a front film 15 and a back film 16 made of the packaging material 70 are prepared. Further, the folded lower film 17 is inserted between the front film 15 and the back film 16. Subsequently, the inner surfaces of the respective films are heat-sealed to form seal portions such as a lower seal portion 12a, a first side seal portion 30, and a second side seal portion 50. The temperature of the heat seal is, for example, 160° C. or higher, and may be 170° C. or higher, or may be 180° C. or higher. The temperature of the heat seal is, for example, 250° C. or lower, and may be 240° C. or lower, or may be 230° C. or lower.

[0191] Cut the surface film 15, the back film 16, and the lower film 17 joined by heat sealing into appropriate shapes. Thereby, the pouch 10 shown in FIG. 1 can be obtained. Subsequently, the contents are filled into the pouch 10 through the opening 11b of the upper part 11. Then, the upper part 11 is heat-sealed along the upper edge to form the upper seal part 11a. In this way, as shown in FIG. 3, the pouch 10 in which the contents 19 are accommodated and sealed can be obtained. Then, a sterilization treatment such as a boiling treatment or a retort treatment may be performed on the pouch 10.

[0192] The pouch 10 of the present embodiment has a first approximate volume V1 of 600,000 [mm 3 . By increasing the first approximate volume V1, the weight of the contents accommodated in the accommodating portion 18 can be increased.

[0193] Method for heating a pouch Next, a method of heating the above-described pouch 10 will be described. First, with the lower part 12 facing down and the pouch 10 in a self-standing state, the pouch 10 is placed inside the microwave oven. Next, the contents are heated using the microwave oven. As a result, the temperature of the contents 19 increases. When the moisture contained in the contents 19 evaporates, the pressure in the accommodating portion 18 increases.

[0194] When the pressure in the accommodating portion 18 increases, the pouch 10 expands. For this reason, a force in the direction from the three-dimensional center point C2 toward the seal part is applied to each position of the seal part. The force applied to each position of the seal part increases as the distance from the three-dimensional center point C2 decreases. The intermediate portion 33 protrudes from the first side portion 13 toward the accommodating portion 18. For this reason, a large force is likely to be applied to the intermediate portion 33.

[0195] When a force is applied to the intermediate portion 33, the peeling of the intermediate portion 33 progresses. When the peeling of the intermediate portion 33 reaches the first unsealed portion 45, a flow path is formed in the intermediate portion 33. The vapor generated in the accommodating portion 18 flows into the first unsealed portion 45 through the flow path.

[0196] The larger the first approximate volume V1 is, the longer the expansion period becomes, and the higher the risk of peeling of the seal portions other than the intermediate portion 33 becomes. In the pouch 10 of the present embodiment, the first parameter U1, which is the ratio of the eighth dimension S8 [mm 3 to the first approximate volume V1 [mm -2 is appropriately determined. Specifically, the pouch 10 has a first parameter U1 of 6.600×10 -5 [mm -2 or more. By appropriately determining the first parameter U1 [mm -2 , as shown in the examples described later, the progress of peeling of the seal portions other than the intermediate portion 33 can be suppressed. For example, the progress of peeling of the lower portion 32 of the first side seal portion 30 and the progress of peeling of the lower portion 52 of the second side seal portion 50 can be suppressed.

[0197] Various changes can be made to the above-described embodiment. Hereinafter, modification 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 portions in the above-described embodiment will be used for the portions that can be configured in the same manner as the above-described embodiment, and redundant descriptions will be omitted. Further, when it is clear that the operational effects obtained in the above-described embodiment can also be obtained in the modification example, the description thereof may be omitted.

[0198] First modification example

[0199] FIG. 13 is a front view showing a modification example of the pouch 10. The lower portion 32 of the first side seal portion 30 may include a portion where the 32nd width W32 increases as it goes from the lower portion 12 toward the intermediate portion 33. For example, a part of the inner edge 32x of the lower portion 32 may be inclined with respect to the second direction D2 so as to move away from the first side edge 13x as it approaches the intermediate portion 33.

Example

[0200] The present invention will be described more specifically with reference to examples. The present invention is not limited to the descriptions of the following examples as long as it does not exceed the gist thereof.

[0201] (Example 1) A packaging material 70 including a first biaxially stretched plastic film 71, a first adhesive layer 76, a second biaxially stretched plastic film 72, a second adhesive layer 77, and a sealant film 75 was prepared. The first biaxially stretched plastic film 71 and the second biaxially stretched plastic film 72 were biaxially stretched PET films having a thickness of 12 μm. The sealant film 75 was the above-described first type of unstretched polypropylene film having a thickness of 70 μm.

[0202] Using the packaging material 70, a pouch 10 shown in FIG. 1 was created. The first dimension S1 to the seventh dimension S7, the tenth dimension S10 to the eleventh dimension S11, the first width W1, the second width W2, the thirty-first width W31 to the thirty-fifth width W35, the forty-first width W41, and the forty-second width W42 of the pouch 10 are shown in FIG. 16.

[0203] Based on the fifth dimension S5 and the seventh dimension S7, an eighth dimension S8 was calculated. The calculation results are shown in FIG. 16.

[0204] Based on the dimensions of each part of the pouch 10, a first approximate volume V1 and first parameters U1 to U3 were calculated. The first approximate volume V1 was 714722.76 [mm 3 . The calculation results are shown in FIG. 16.

[0205] Based on the dimensions of each part of the pouch 10 and the first approximate volume V1, the first approximate volume V1 and first parameters U1 to U3 were calculated. The first parameter U1 was 7.252×10 -5 [mm -2 . The calculation results are shown in FIG. 16.

[0206] For the pouch 10, the following evaluations 1 and 2 were performed.

[0207] [Evaluation 1] The pouch 10 was filled with the contents. The contents were water. The weight of the contents was 270 g. Subsequently, the upper part 11 was heat-sealed to form the upper seal part 11a.

[0208] The conditions for heat-sealing are as follows. · Heat-sealing device: Heat Sealer TP-701-A (manufactured by Tester Sangyo Co., Ltd.) · Heat-sealing temperature: 225 °C · Heat-sealing pressure: 0.1 MPa · Heat-sealing time: 1 second

[0209] With the pouch 10 containing 270 g of the contents, it was visually confirmed whether the pouch 10 was properly sealed by the upper seal part 11a. It was confirmed that the pouch 10 was properly sealed. "Good" in the "Evaluation 1" column of Fig. 16 means that the pouch 10 was properly sealed.

[0210] 〔Evaluation 2〕 The pouch 10 containing 270 g of the contents and sealed was subjected to retort treatment under the following conditions. · Method: Spray type · Retort temperature: 121 °C · Retort time: 30 minutes

[0211] With the lower part 12 facing down and the pouch 10 standing upright, the pouch 10 was placed inside the microwave oven. Subsequently, the pouch 10 was heated with a microwave oven with an output of 600 W for 300 seconds. As the microwave oven, RE-TS3 manufactured by Sharp was used.

[0212] It was confirmed whether peeling occurred in the lower part 32 of the first side seal part 30 of each pouch 10 after heating. The results are shown in the column of "Evaluation 2" in Fig. 16. "A" means that the width of the lower part 32 remaining without peeling was 3 mm or more. "B" means that the width of the lower part 32 remaining without peeling was 2 mm or more and less than 3 mm. "C" means that the width of the lower part 32 remaining without peeling was 1 mm or more and less than 2 mm. "D" means that the width of the lower part 32 remaining without peeling was less than 1 mm, or the lower part 32 was completely peeled off. The width of the lower part 32 remaining without peeling is measured at the position of the plane center point C1 in the second direction D2. In Example 1, the result of Evaluation 2 was B.

[0213] (Example 2) Using the same packaging material 70 as in the case of Example 1, the pouch 10 shown in Fig. 13 was created. The dimensions of each part of the pouch 10, the first approximate volume V1, and the first parameter U1 to the third parameter U3 are shown in Fig. 16.

[0214] Similar to the case of Example 1, Evaluation 1 and Evaluation 2 were performed. The evaluation results are shown in Fig. 16.

[0215] (Comparative Example 1) Using the same packaging material 70 as in the case of Example 1, the pouch 10 shown in Fig. 14 was created. The dimensions of each part of the pouch 10, the first approximate volume V1, and the first parameter U1 to the third parameter U3 are shown in Fig. 16. The main differences between the pouch 10 of Comparative Example 1 and the pouch 10 of Example 1 are that the second dimension S2, the fourth dimension S4, and the eleventh dimension S11 are enlarged.

[0216] Similar to the case of Example 1, Evaluation 1 and Evaluation 2 were performed. The evaluation results are shown in Fig. 16.

[0217] (Comparative Example 2) Using the same packaging material 70 as in Example 1, the pouch 10 shown in FIG. 15 was created. The dimensions of each part of the pouch 10, the first approximate volume V1, and the first parameter U1 to the third parameter U3 are shown in FIG. 16. The main differences between the pouch 10 of Comparative Example 2 and the pouch 10 of Example 1 are that the second dimension S2, the fourth dimension S4, and the tenth dimension S10 are enlarged.

[0218] Similar to the case of Example 1, Evaluation 1 and Evaluation 2 were performed. The evaluation results are shown in FIG. 16.

[0219] All of the pouches 10 of Examples 1 to 2 and Comparative Examples 1 to 2 have a first approximate volume V1 of 600,000 [mm 3 . As can be seen from Evaluation 1, all of the pouches 10 of Examples 1 to 2 and Comparative Examples 1 to 2 were properly sealed with 270 g of the content accommodated. The first approximate volume V1 is considered to be an appropriate index regarding the volume of the accommodating portion 18 of the pouch 10.

[0220] The first parameter U1 of the pouches 10 of Examples 1 to 2 is 7.000×10 -5 [mm -2 or more. The first parameter U1 of the pouches 10 of Comparative Examples 1 to 2 is less than 7.000×10 -5 [mm -2 . As can be seen from Evaluation 1, in the pouches 10 of Examples 1 to 2, the progress of peeling of the lower portion 32 of the first side seal portion 30 was suppressed as compared with the pouches 10 of Comparative Examples 1 to 2.

Explanation of Signs

[0221] 10 Pouch 11 Upper part 11a Upper seal portion 12 Lower part 12a Lower seal portion 13 First side portion 13x First side edge 14 Second side portion 14x Second side edge 15 Surface film 16 Back film 17 Lower film 18 Accommodation part 25 Steam venting mechanism 30 First side seal part 31 Upper part 32 Lower part 33 Middle part 33x Inner edge 45 First non-seal part 46 Opening edge part 47 Through part 50 Second side seal part 51 Upper part 52 Lower part 53 Middle part 65 Second non-seal part 66 Opening edge part 70 Packaging material 70x Inner surface 70y Outer surface 71 First biaxially stretched plastic film 72 Second biaxially stretched plastic film 73 Third biaxially stretched plastic film 75 Sealant film 76 First adhesive layer 77 Second adhesive layer 78 Third adhesive layer 81 Printing layer 82 Transparent vapor deposition layer 83 Transparent gas barrier coating film

Claims

1. A self - supporting pouch, including a front film and a back film, a lower film positioned between the front film and the back film in a folded state at the folded portion and located at the lower part of the pouch, a first side seal portion located at a first side portion of the pouch and joining the inner surface of the front film and the inner surface of the back film, a second side seal portion located at a second side portion facing the first side portion of the pouch in a first direction and joining the inner surface of the front film and the inner surface of the back film, a lower seal portion including a first lower seal portion joining the inner surface of the front film and the inner surface of the lower film and a second lower seal portion joining the inner surface of the back film and the inner surface of the lower film, a storage portion surrounded by the first side seal portion, the second side seal portion and the lower seal portion for storing contents, a first non - seal portion located near the upper part of the pouch and separated from the storage portion by the first side seal portion, an upper seal portion is formed by joining the inner surface of the front film and the inner surface of the back film at the upper part of the pouch, the first side seal portion includes an intermediate portion located between the storage portion and the first non - seal portion, an upper portion extending along the first side from the intermediate portion to the upper seal portion, and a lower portion extending along the first side from the intermediate portion to the lower seal portion, the pouch has a fifth dimension (S5), a seventh dimension (S7), an eighth dimension (S8), a tenth dimension (S10), an eleventh dimension (S11) and a first approximate volume (V1), the fifth dimension (S5) is the distance on the surface of the front film between the lower end of the inner edge of the first lower seal portion and the folded portion, the seventh dimension (S7) is the distance on the surface of the front film between the center point (C1) of the storage portion and the inner edge of the first side seal portion, the eighth dimension (S8) is calculated based on the following formula, S8 = ((S7) ２ - (S5) ２ ) ０．５ the tenth dimension (S10) is the distance on the surface of the front film between the inner edge of the upper seal portion and the lower end of the inner edge of the intermediate portion, the eleventh dimension (S11) is the distance on the surface of the front film between the lower end of the inner edge of the first lower seal portion and the lower end of the inner edge of the intermediate portion, the first approximate volume (V1) is calculated based on the following formula, V1 = 3.14 × S5 × S8 × S11 + S5 × S10 × S8 × 2 The first approximate volume (V1) [mm ３ , and the first parameter (U1), which is the ratio of the eighth dimension (S8) [mm] to the first approximate volume (V1), is 7.000 × 10 －５ [mm －２ or more. The pouch.

2. The first approximate volume (V1) is 600,000 [mm ３ , and the pouch according to claim 1 is as follows.

3. The pouch according to claim 2, wherein the weight of the content accommodated in the accommodating portion is 230 g or more.

4. The pouch has a first dimension (S1) of 145 mm or less, The first dimension (S1) is the distance on the surface film between the side edges of the first side portion and the side edges of the second side portion. The pouch according to claim 1.

5. The pouch has a fourth dimension (S4) of 150 mm or less, The fourth dimension (S4) is the distance on the surface film between the inner edge of the upper seal portion and the lower end of the inner edge of the first lower seal portion. The pouch according to any one of claims 1 to 4.

6. The pouch has a sixth dimension (S6) of 61 mm or more and 69 mm or less, The sixth dimension (S6) is the distance on the surface film between the center point (C1) of the accommodating portion and the inner edge of the intermediate portion. The pouch according to any one of claims 1 to 4.

7. The pouch has a sixth dimension (S6), The sixth dimension (S6) is the distance on the surface film between the center point (C1) of the accommodating portion and the inner edge of the intermediate portion, The third parameter (U3), which is the ratio of the sixth dimension (S6) to the seventh dimension (S7), is 0.95 or more and 1.05 or less. The pouch according to any one of claims 1 to 4.

8. The pouch has a second width (W2), The second width (W2) is the minimum value of the width of the first lower seal portion, The second parameter (U2), which is the ratio of the second width (W2) to the fifth dimension (S5), is 0.20 or more. The pouch according to any one of claims 1 to 4.

9. The packaging material constituting the surface film and the back film includes a biaxially stretched plastic film and a sealant film, The sealant film contains polypropylene, The polypropylene contains block polypropylene. The pouch according to any one of claims 1 to 4.

10. The pouch according to claim 9, wherein the content of polypropylene in the sealant film is 80% by mass or more.

Images