Steam-permeable pouch

Abstract

To provide a steam penetrative pouch an unsealing portion of which can beautifully be torn straight with hands and out of which its contents can easily be taken.SOLUTION: A steam penetrative pouch 10 comprises opposite body member sheets 20 and a bottom member sheet, has a storage space 11 storing the contents by sealing peripheral edges of a left side surface and a right side surface and a bottom surface and, after filling contents 15, hermetically sealing an upper surface, and includes, in at least one of seal portions of the left and right side surfaces, a steam penetrative portion 60 for allowing steam in the storing space to escape during heating and an unsealing portion 50 formed on a bottom-surface side or an upper-surface side of the steam penetrative portion so as to be substantially parallel to the bottom surface. The body member sheets and the bottom member sheet each includes an outermost layer and a sealant layer. The sealant layer of each of the body member sheets is composed of a material excellent in heat resistance and ability to easily be torn in a width direction. The sealant layer of the bottom member sheet is composed of a material excellent in heat resistance and ability to spread at the bottom.SELECTED DRAWING: Figure 1

Description

Technical Field

[0001] The present invention relates to a steam-permeable pouch that can be easily torn open with a hand or the like and can also be used as a container for eating after opening.

Background Art

[0002] For example, pouches for microwave ovens that contain heated contents such as retort foods and frozen foods are widely used. When this pouch is heated in a microwave oven, the moisture contained in the contents evaporates as the heating progresses, increasing the pressure inside the pouch. If the pressure inside the pouch increases, there is a risk that the pouch will burst and the contents will scatter, soiling the inside of the microwave oven. Therefore, a steam-permeable pouch equipped with a steam venting mechanism is known to release the increased pressure inside the pouch to the outside.

[0003] A steam-permeable pouch includes a sheet sealed so as to form an accommodation space capable of accommodating the contents, and a steam-permeable portion in which a part of the sheet is sealed so as to open as the pressure in the accommodation space rises. When the pressure in the accommodation space rises to a certain extent due to heating, the seal forming the steam-permeable portion peels off, and a passage communicating the accommodation space and the external space is formed in the steam-permeable portion. For this reason, the moisture in the accommodation space passes through the passage formed in the steam-permeable portion and is discharged to the outside of the pouch, suppressing the rise in the pressure in the accommodation space.

[0004] Patent Document 1 discloses a pouch for a microwave oven, which is an example of a conventional steam-permeable pouch. As shown in Patent Document 1, this pouch for a microwave oven includes a laminated sheet. The laminated sheet includes a base material layer, a printing layer, other layers, and a sealant layer. When heating of the pouch for a microwave oven containing the contents is completed by heating means, the laminated sheet is torn from the opening portion, and the contents are taken out from the accommodation space.

Prior Art Documents

Patent Documents

[0005]

Patent Document 1

[0006] However, with the microwave pouch described in Patent Document 1, when attempting to tear the laminated sheet from the opening by hand, the innermost sealant layer stretches during the tearing process, preventing a straight tear, causing fuzzing or wavy deformation at the tear site. This results in an insufficient opening, making it difficult to easily remove the contents from the opening.

[0007] The present invention has been made in view of the above problems, and aims to provide a steam-permeable pouch in which the opening can be neatly and linearly torn by hand or the like, and the contents can be easily removed. [Means for solving the problem]

[0008] According to claim 1 of the present invention, it consists of opposing body member sheets and a bottom member sheet that is folded into the bottom surface, sealing the peripheral edges of the left side, right side and bottom surface, and further sealing the top surface after filling with contents. By doing so, it has a storage space for containing the contents, At least one of the sealing portions on the left and right sides is provided to allow steam from the containment space to escape when heated. A steam passage section and an opening section on the bottom or top side of the steam passage section that is substantially parallel to the bottom surface. It is a steamed pouch, The aforementioned body member sheet and bottom member sheet have the outermost layer, intermediate layer, and sealant layer reduced, respectively. This also includes, The outermost layer is made of transparent vapor-deposited polyethylene terephthalate, The aforementioned intermediate layer is made of a material that has excellent heat resistance and easy tearing properties in the width direction. The opening portion is further provided with a guide portion that guides the cutting of the sheet from the right end of the left side seal portion to the left end of the right side seal portion, and the guide portion includes a cutting line provided only in the intermediate layer. The sealant layer of the aforementioned body member sheet is made of a material that has excellent heat resistance and easy tearing in the width direction. The sealant layer of the bottom member sheet is made of unstretched polypropylene.

[0009] When a steam-permeable pouch is heated with contents contained within its storage space, a passage connecting the storage space to the outside space is formed in the steam-permeable section as the pressure inside the storage space increases. As a result, water vapor from the storage space is discharged to the outside of the steam-permeable pouch through the passage formed in the steam-permeable section, suppressing the rise in pressure inside the storage space. Furthermore, since the sealant layer of the body sheet is made of a material that is easily torn in the width direction, the sheet can be easily torn in the width direction. As a result, the contents can be easily removed from the torn portion of the body sheet. In addition, since the sealant layer of the bottom sheet is made of a material that has appropriate stiffness and bottom-opening properties, the suitability of the container for filling is ensured.

[0010] Furthermore, according to claim 2 of the present invention, the sealant layer of the body member sheet contains 3 to 10 parts by weight of low-crystallinity ethylene-based elastomer per 100 parts by weight of propylene-ethylene block copolymer, wherein the low-crystallinity ethylene-based elastomer has a density of 0.865 to 0.890 g / cm³. 3 The material is made of unstretched polypropylene, which falls within the specified range and whose heat absorption during melting falls within the range of 5 to 30 J / g as defined in JIS standard 7122, and the sealant layer of the bottom member sheet is made of unstretched polypropylene. Polypropylene is a resin with excellent heat resistance and can be suitably used as a material for microwave pouches that require boiling and retort suitability.

[0011] Furthermore, the sealant layer of the body sheet has easy tearing properties in the width direction, allowing the sheet to be easily torn in that direction. Although short, thread-like fibers may remain in the torn area, this phenomenon is almost nonexistent with polypropylene. Therefore, the contents can be easily removed from the torn area of ​​the sheet.

[0012] In addition, the sealant layer of the bottom member sheet is made of non-stretched polypropylene. Non-stretched polypropylene is a film formed by molding a polypropylene material without stretching. Since it stretches when pulled, it has no easy tearability and is not suitable for the body member, but it is flexible and has bottom-opening properties, so it has filling suitability and is not easily torn even when pulled.

[0013] Also ,before Both the body member sheet and the bottom member sheet, or at least one of them, further include an intermediate layer laminated between the outermost layer and the sealant layer. For this reason, the strength of the steam-permeable pouch is increased.

[0014] Also ,before The intermediate layer is composed of a material excellent in heat resistance and easy tearability in the width direction. Since the intermediate layer is composed of a material excellent in easy tearability in the width direction, the sheet can be easily torn. For this reason, the contents can be easily taken out from the torn part of the sheet.

[0015] Also ,before The opening part has a notch in at least one of the seal parts on the left and right side faces, and further includes a guide part for guiding the cutting of the sheet from the right end of the left side face seal part to the left end of the right side face seal part. According to the above steam-permeable pouch, the sheet can be easily torn along the guide part with the notch as the starting point of tearing. For this reason, the contents can be easily taken out from the torn part of the sheet.

[0016] Also ,before The guide part includes a cutting line provided in the intermediate layer. According to the above steam-permeable pouch, even when the intermediate layer is provided, the sheet can be easily torn. For this reason, the contents can be easily taken out from the torn part of the sheet.

Effects of the Invention

[0017] According to the steam-permeable pouch of the present invention, the opening can be linearly and beautifully torn by hand or the like, and the contents can be easily taken out.

Brief Description of the Drawings

[0018] [Figure 1] Front view of a steam-permeable pouch showing an example of an embodiment of the present invention. [Figure 2] Cross-sectional view showing the layer structure of the body member sheet and the bottom member sheet. [Figure 3] Enlarged view of the steam-permeable part and its periphery in the opened state. [Figure 4] Front view of the steam-permeable pouch in the opened state.

Embodiments for Carrying Out the Invention

[0019] Hereinafter, an example of an embodiment of the present invention will be described. FIG. 1 shows an example of a steam-permeable pouch 10 that can accommodate the contents 15 suitable for heating and discharge the steam generated from the contents 15. The contents 15 are objects to be heated that generate water vapor when heated. An example of the contents 15 is food. An example of the food is food having fluidity such as stew and soup. The steam-permeable pouch 10 is configured to be able to store the contents 15 for a long time while maintaining the quality of the contents 15. Examples of the shapes that the steam-permeable pouch 10 can take are self-standing types such as a standing type and a gusset type. The shape of the steam-permeable pouch 10 illustrated in FIG. 1 is a standing type. Hereinafter, in the front view of the steam-permeable pouch 10, the left-right direction of the steam-permeable pouch 10 will be referred to as the standard width direction, and the direction orthogonal to the standard width direction will be referred to as the standard height direction.

[0020] The permeable pouch 10 includes a body sheet 20, a bottom sheet 23, a top sealing section 31, a bottom sealing section 32, a right side sealing section 33, a left side sealing section 34, an opening section 50, and a permeable section 60. The body sheet 20 consists of a front sheet 21 and a back sheet 22. The front sheet 21 and the back sheet 22 face each other such that a storage space 11 for accommodating the contents 15 is formed between the sheets 21 and 22. The bottom sheet 23 is folded around its periphery to seal the space between the bottom of the front sheet 21 and the bottom of the back sheet 22.

[0021] The body member sheets 20 (21, 22) and the bottom member sheet 23 have a layered structure in which multiple layers are laminated. Figure 2(a) is a cross-sectional view showing the layered structure of the body member sheet, and Figure 2(b) is a cross-sectional view showing the layered structure of the bottom member sheet. The body member sheets 20 (21, 22) include an outermost layer 20A, an intermediate layer 20B, a sealant layer 20C, a first adhesive layer 20D, and a second adhesive layer 20E. Similarly, the bottom member sheet 23 includes an outermost layer 23A, an intermediate layer 23B, a sealant layer 23C, a first adhesive layer 23D, and a second adhesive layer 23E. One example of a manufacturing method for each sheet 21-23 is dry lamination. The first adhesive layer of each sheet 21-23 is provided between the outermost layer and the intermediate layer, and the second adhesive layer is provided between the intermediate layer and the sealant layer.

[0022] The outermost layer 20A of the body member sheet 20 (21, 22) is mainly excellent in gas barrier properties, printability, and heat resistance. The outermost layer 20A is, for example, a transparent vapor-deposited layer. An example of the material constituting the outermost layer 20A is polyethylene terephthalate with an inorganic thin film vapor-deposited on it (hereinafter referred to as "vapor-deposited PET"). The intermediate layer 20B is mainly excellent in heat resistance and moisture resistance. The material constituting the intermediate layer 20B is nylon (hereinafter referred to as, which has easy tearing properties in the width direction of the body member sheet 20) This is called "Easy-Cut Ny". In the following, the orientation direction of the material constituting each sheet 21 and 22 will be referred to as the MD (Machine Direction) direction, and the direction perpendicular to the MD direction will be referred to as the TD (Transverse Direction) direction. The MD direction of each sheet 21 and 22 is the direction along the standard width direction. The TD direction of each sheet 21 and 22 is the direction along the standard height direction. An example of the material constituting the first adhesive layer 20D is a polyester adhesive. An example of the material constituting the second adhesive layer 20E is a polyester adhesive.

[0023] Regarding the bottom sheet 23, the outermost layer 23A is made of the same material as the outermost layer 20A of the body sheet 20, but an example of the material for the intermediate layer 23B is unstretched nylon that is not easily cut.

[0024] The sealant layer 20C of the body member sheet 20 has excellent heat resistance, heat sealability, and impact resistance. An example of the material constituting the sealant layer 20C is unoriented polypropylene (hereinafter referred to as "easy-cut CPP") which has excellent tear resistance in the MD direction.

[0025] Excellent tear resistance in the MD direction means, for example, that the tear force conforming to the Trouser tear method specified in JIS standard K7128-1 is 1.2 N or less. In the Trouser tear method, a rectangular test specimen with a length of 50 mm in the TD direction and a length of 150 mm in the MD direction was cut 75 mm in the center, and the tear force in the MD direction was measured at a speed of 200 mm / min in a constant temperature room at 23°C.

[0026] The easily cut CPP contains, for example, 3 to 10 parts by weight of a low-crystallinity ethylene-based elastomer per 100 parts by weight of propylene-ethylene block copolymer. The low-crystallinity ethylene-based elastomer has, for example, a density of 0.865 to 0.890 g / cm³. 3 It falls within the specified range, and the heat absorption during melting specified in JIS standard 7122 falls within the range of 5 to 30 J / g.

[0027] The sealant layer 23C of the bottom sheet 23 has excellent heat resistance, heat sealability, and flexibility, and is suitable for bottom opening. It is also an unstretched film and has the property of stretching when pulled, but it is not easily cut.

[0028] The sealing sections 31-34 shown in Figure 1 join the sheets 21-23 together so that they do not separate. One example of a method for forming the sealing sections 31-34 is heat sealing. The outer shape of the permeable pouch 10 in a front view can be arbitrarily selected. In the example shown in Figure 1, the outer shape of the permeable pouch is rectangular.

[0029] The opening section 50 has a notch 51 on at least one of the sealing sections on the left and right sides, and a guide section 52 is provided on the body member sheet 20 at the same height as the notch 51 in the standard height direction, guiding the cutting of the body member sheet 20 from the right end of the left side sealing section to the left end of the right side sealing section. The position in which the opening section 50 (notch 51, guide section 52) is provided can be arbitrarily selected in the standard height direction. In one example shown in Figure 1, the opening section 50 is provided between the steam passage section 60 and the bottom member sheet 23 in the standard height direction. In a preferred example, it is provided closer to the steam passage section 60 than to the bottom member sheet 23 in the standard height direction. In another example, the opening section 50 is provided between the steam passage section 60 and the top sealing section 31 in the standard height direction.

[0030] The guide portion 52 is a collection of perforations formed on the body member sheet 20, and is formed to follow the MD direction of the body member sheet 20. The notch 51 is formed on at least one of the right side seal portion 33 and the left side seal portion 34 such that the tip of the notch 51 is located on a virtual line extending from the guide portion 52. Figure 1 shows an example in which the notch 51 is formed on the left side seal portion 34.

[0031] The opening portion 50 where the guide portion 52 is formed has lower tear strength than other parts of the body member sheet 20 where the guide portion 52 is not formed. Therefore, when a force is applied to the opening portion 50 in the direction along the guide portion 52, the body member sheet 20 is easily torn along the guide portion 52. The guide portion 52 includes a plurality of discontinuously formed notches 52A in the standard width direction. A means for forming the guide portion 52 is, for example, a perforating machine.

[0032] The shape of the notch 52A can be straight, curved, perforated, dashed, or any other shape, and the number of notches can be one or more in the standard height direction. In this invention, it is sufficient that the notch 52A portion is weakened and acts as a cut in the opening portion 50.

[0033] In a preferred example, the notch 52A does not penetrate all three layers of the body member sheet 20, namely the outermost layer 20A, the intermediate layer 20B, and the sealant layer 20C, but is formed in one or two of the three layers. Because the notch 52A does not penetrate all three layers of the body member sheet 20, the contents 15 contained in the containment space 11 do not pass through the guide portion 52 to the outside. In this embodiment, the notch 52A is provided so as to penetrate only the intermediate layer 20B of the body member sheet 20.

[0034] The steam-permeable pouch 10 is heated by a heating means to heat the contents 15. An example of a heating means is a microwave oven. As the steam-permeable pouch 10 is heated, steam is generated from the contents 15. As steam is generated, the pressure in the containment space 11 increases. The steam vent 60 is configured to open as the pressure in the containment space 11 increases, allowing the steam from the containment space 11 to be discharged to the outside of the steam-permeable pouch 10. In a preferred example, the steam vent 60 is configured to open when the pressure in the containment space 11 rises to a pressure within a predetermined pressure range.

[0035] The steam passage section 60 can take various forms. In one example, the steam passage section 60 is provided on at least one of the right side seal section 33 and the left side seal section 34. In another example, the steam passage section 60 is provided on the inside of the seal section, independently of the right side seal section 33 and the left side seal section 34. Figure 1 shows an example where it is provided only on the right side seal section 33.

[0036] The shape of the steam passage section 60 is such that it is recessed from the outside in the standard width direction. The tip 61, which is the innermost part of the steam passage section 60 in the standard width direction, is located where strong stress concentration occurs when the pressure in the containment space 11 of the body member sheet 20 rises. It opens when the pressure in the containment space 11 rises to a pressure within a predetermined pressure range.

[0037] Specifically, as the pressure in the containment space 11 increases, the front sheet 21 and the back sheet 22, which are joined at the tip 61 of the steam vent section 60, separate, and a steam vent passage 62 is formed in the steam vent section 60, connecting the containment space 11 to the outside of the steam-permeable pouch 10, as shown in Figure 3. The extent to which the steam vent section 60 separates varies depending on the magnitude of the pressure in the containment space 11. If the pressure in the containment space 11 is high, the separation may progress to the base of the steam vent section 60. The passage area of ​​the steam vent passage 62 widens as the separation of the steam vent section 60 progresses. When the steam vent section 60 opens, the water vapor in the containment space 11 passes through the steam vent passage 62 and is discharged to the outside of the steam-permeable pouch 10. By discharging the water vapor, the increase in pressure in the containment space 11 is suppressed, and the rupture of the steam-permeable pouch 10 is avoided.

[0038] Figure 4 shows a steam-permeable pouch 10 with the opening section 50 opened after cooking. When opening the opening section 50, the body sheet 20 is torn from the tip of the notch 51, and force is applied to the body sheet 20 so that the tearing of the body sheet 20 progresses along the guide section 52, and the entire opening section 50 is opened. The user can use the steam-permeable pouch 10, which has been opened from the opening section 50, as a container and eat the contents 15. [Examples]

[0039] Using samples from the examples and comparative examples, tests were conducted to confirm the relationship between the layer structure of the body sheet 20 and the bottom sheet 23 and their tearability and bottom opening properties. The samples were retort pouches containing curry. After heating the samples in a 600W microwave oven for 1 minute, the tearability (hereinafter referred to as "cutability") and bottom opening properties of the body sheet 20 were evaluated using a 5-point scoring system. The scoring system is as follows: "5: Good > 4: Fair > 3: Average > 2: Fair > 1: Poor". Table 1 shows the layer structure and the scoring results for cutability and bottom opening properties of the samples.

[0040] The meanings of the material terms shown in Table 1 are as follows:

[0041] <Transparent vapor-deposited PET12> A transparent vapor-deposited film made by depositing aluminum oxide onto a polyethylene terephthalate film (12 μm thick). <Easy-cut PET12> A polyethylene terephthalate film (12 μm thick) with excellent tear resistance in the MD direction. Excellent tear resistance in the MD direction means, for example, that the tear force conforming to the trouser tear test specified in JIS standard K7128-1 is 1.2 N or less. <Easy-cut CPP60> An unstretched polypropylene film (60 μm thick) comprising 3 to 10 parts by weight of a low-crystallinity ethylene-based elastomer per 100 parts by weight of propylene-ethylene block copolymer, wherein the low-crystallinity ethylene-based elastomer has a density in the range of 0.865 to 0.890 g / cm³ and a heat absorption during melting in the range of 5 to 30 J / g as specified in JIS standard 7122. <Easy-cut Ny15> A polyamide film (15 μm thick) with excellent tear resistance in the MD direction. <pet12> A polyethylene terephthalate film (12 μm thick) with poor tear resistance in the MD direction. Poor tear resistance in the MD direction means, for example, that the tear force according to the trouser tear test specified in JIS standard K7128-1 exceeds 1.2 N. <cpp60> An unoriented polypropylene film (60 μm thick) with poor tear resistance in the MD direction. <ny15> A polyamide film (15 μm thick) with poor tear resistance in the MD direction.

[0042] [Table 1]

[0043] As can be seen in Table 1, when the sealant layer of the body sheet is made of easily cuttable CPP and the sealant layer of the bottom member is made of CPP, the best steam-permeable pouch with the best cutability and bottom opening suitability is obtained.

[0044] From the above, the steam-permeable pouch of the present invention provides the following functions and effects. When the steam-permeable pouch, which is sealed with contents contained in the containment space, is heated, a steam vent passage connecting the containment space to the outside is formed in the steam-permeable section as the pressure in the containment space rises. As a result, the water vapor in the containment space is discharged to the outside of the steam-permeable pouch through the steam vent passage, and the rise in pressure in the containment space is suppressed.

[0045] Furthermore, since the sealant layer of the body sheet is made of a material with excellent tear resistance in the MD direction, the body sheet can be easily torn by hand from the opening. Therefore, the contents can be easily removed from the opening. Also, the sealant layer of the bottom sheet is M Because it is made of a material that does not have good tear resistance in the D direction, it is flexible and has bottom-opening properties, so it can provide a steam-permeable pouch that is suitable for filling. [Explanation of Symbols]

[0046] 10... Steam-type pouch 11. Containment space 15...Contents 20...body material sheet 20A... Outermost layer of body sheet 20B...Intermediate layer of body sheet 20C...Sheet sealant layer for body members 20D...First adhesive layer of the body member sheet 20E...Second adhesive layer of the body member sheet 21... Front seat 22...Rear seat 23...Bottom material sheet 23A...Outermost layer of bottom sheet 23B...Bottom material sheet intermediate layer 23C...Bottom material sheet sealant layer 23D...First adhesive layer of the bottom sheet 23E...Second adhesive layer of the bottom sheet 31. Top sealing section 32...Bottom seal section 33. Right side seal section 34. Left side seal section 50...Opening part 51 notches 52... Guide section 52A... Notch 60...Steaming section 61... Tip of the steam passage section 62... Steam vent passage

Claims

1. It consists of opposing body sheet members and a bottom sheet member that is folded into the bottom surface. The left side, right side, and bottom edges are sealed, and after filling with contents, the top surface is sealed to create a storage space for the contents. A steam-permeable pouch comprising, at least one of the sealing portions on the left and right sides, a steam-permeable portion for releasing steam from the containment space during heating, and an opening portion that is substantially parallel to the bottom surface only on the upper side of the steam-permeable portion, The body member sheet and the bottom member sheet each include at least an outermost layer, an intermediate layer, and a sealant layer. The outermost layer is made of transparent vapor-deposited polyethylene terephthalate, The intermediate layer of the body member sheet is made of polyethylene terephthalate having a widthwise tear force of 1.2 N or less, in accordance with the trouser tear method specified in JIS K7128-1. The intermediate layer of the body member sheet is composed of a single layer. The opening portion is further provided with a guide portion that guides the cutting of the sheet from the right end of the left side seal portion to the left end of the right side seal portion, and the guide portion includes a cutting line provided only in the intermediate layer of the body member sheet. The sealant layer of the body member sheet is made of a material having a widthwise tear force of 1.2 N or less, in accordance with the trouser tear test specified in JIS K7128-1. The sealant layer of the bottom member sheet is made of unstretched polypropylene. The intermediate layer of the bottom sheet is a breathable pouch made of nylon with a widthwise tear force exceeding 1.2 N, in accordance with the trouser tear method specified in JIS K7128-1.

2. The sealant layer of the body member sheet contains 3 to 10 parts by weight of low-crystallinity ethylene elastomer per 100 parts by weight of propylene-ethylene block copolymer, wherein the low-crystallinity ethylene elastomer has a density of 0.865 to 0.890 g / cm³. ３ A steam-permeable pouch according to claim 1, made of unstretched polypropylene that falls within the range and whose heat absorption during melting is within the range of 5 to 30 J / g as defined in JIS K7122.

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