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 comprises a body member sheet and a bottom member sheet folded at a bottom, has a storing space for storing contents by sealing peripheral edges of a left side surface and a right side surface and a bottom surface of the body member sheet and the bottom member sheet to form a seal portion and, after filling contents, hermetically sealing an upper surface of the body member sheet, and includes, in at least one of the seal portions of the left and right side surfaces, a steam penetrative portion for allowing steam in the storing space to escape during heating and an unsealing portion 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 sheet is composed of a material containing no polyamide, and the bottom member sheet is composed of a material containing polyamide.SELECTED DRAWING: Figure 1

Description

Technical Field

[0001] The present invention relates to a steam-permeable pouch that can be easily torn open by 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 with heating, and the pressure inside the pouch increases. 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 contents, and a steam vent 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 by heating, the seal forming the steam vent portion peels off, and a passage communicating the accommodation space and the external space is formed in the steam vent portion. For this reason, the moisture in the accommodation space passes through the passage formed in the steam vent 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 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 a body member sheet and a bottom member sheet 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. 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-permeable pouch comprising a steam-permeable section and an opening section on the bottom or top side of the steam-permeable section that is substantially parallel to the bottom surface, The body member sheet and the bottom member sheet each include at least an outermost layer and a sealant layer. The body member sheet is made of a material that does not contain polyamide, and the bottom member sheet is made of a material that contains polyamide.

[0009] When a steam-permeable pouch is heated with its contents contained within, a passage connecting the containment space to the outside space is formed in the steam-permeable section as the pressure inside the containment space increases. As a result, water vapor from the containment 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 containment space. Furthermore, polyamide has excellent impact resistance, so it will not tear even when pulled. Therefore, although it is not suitable for body sheet material where easy tearing is required, when used for bottom sheet material, it has appropriate stiffness and bottom opening properties, ensuring suitability for filling as a container.

[0010] Furthermore, according to claim 2 of the present invention, both or at least one of the body member sheet and the bottom member sheet further include an intermediate layer laminated between the outermost layer and the sealant layer. This increases the strength of the steam-permeable pouch.

[0011] Furthermore, according to claim 3 of the present invention, since the intermediate layer is made of a material that has excellent heat resistance and ease of tearing in the width direction, the sheet can be easily torn. Therefore, the contents can be easily removed from the torn portion of the sheet.

[0012] Furthermore, according to claim 4 of the present invention, the opening portion has a notch in at least one of the sealing portions on the left and right sides, and further comprises a guide portion that guides the cutting of the sheet from the right end of the left side sealing portion to the left end of the right side sealing portion. With the above-described steam-permeable pouch, the notch can be used as the starting point for tearing, and the sheet can be easily torn along the guide portion. As a result, the contents can be easily removed from the torn portion of the sheet.

[0013] Furthermore, according to claim 5 of the present invention, the guide portion includes a perforation line provided in the intermediate layer. With the above-described steam-permeable pouch, even when the intermediate layer is provided, the sheet can be easily torn. Therefore, the contents can be easily removed from the torn portion of the sheet. [Effects of the Invention]

[0014] According to the steam-permeable pouch of the present invention, the opening can be neatly and cleanly torn open by hand or other means, allowing the contents to be easily removed. [Brief explanation of the drawing]

[0015] [Figure 1] A front view of a steam-permeable pouch, illustrating an example of an embodiment of the present invention. [Figure 2] A cross-sectional view showing the layer structure of the body sheet and the bottom sheet. [Figure 3] Enlarged view of the steam passage and its surroundings in an open state. [Figure 4] Front view of an opened steam-permeable pouch. [Modes for carrying out the invention]

[0016] The following describes an example of an embodiment of the present invention. Figure 1 shows an example of a steam-permeable pouch 10 that can contain contents 15 suitable for heating and allow steam generated from the contents 15 to be discharged. The contents 15 are a heated object that generates steam when heated. An example of the contents 15 is food. An example of food is a fluid food such as stew and soup. The steam-permeable pouch 10 can store the contents 15 for a long period of time while maintaining their quality. It is configured in such a way. Examples of shapes that the steam-permeable pouch 10 can take include self-standing types such as standing type and gusset type. The shape of the steam-permeable pouch 10 exemplified in Figure 1 is a standing type. Hereinafter, the left-right direction of the steam-permeable pouch 10 in a front view will be referred to as the standard width direction, and the direction perpendicular to the standard width direction will be referred to as the standard height direction.

[0017] The steam-through type pouch 10 includes a body member sheet 20, a bottom member sheet 23, an upper seal portion 31, a bottom seal portion 32, a right side seal portion 33, a left side seal portion 34, an opening portion 50, and a steam-through portion 60. The body member 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 content 15 is formed between the sheets 21 and 22. The bottom member sheet 23 is sealed with its periphery folded in to close the space between the bottom of the front sheet 21 and the bottom of the back sheet 22.

[0018] The body member sheet 20 (21, 22) and the bottom member sheet 23 have a layer structure in which a plurality of layers are laminated. FIG. 2(a) is a cross-sectional view showing the layer configuration of the body member sheet, and FIG. 2(b) is a cross-sectional view showing the layer configuration of the bottom member sheet. The body member sheet 20 (21, 22) includes 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. An example of the manufacturing method of each of the sheets 21 to 23 is dry lamination. The first adhesive layer of each of the sheets 21 to 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.

[0019] 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 deposition layer. An example of the material constituting the outermost layer 20A is polyethylene terephthalate with an inorganic thin film deposited thereon (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, for example, polyethylene terephthalate having easy tearability in the width direction of the body member sheet 20 (hereinafter referred to as "easily cut PET"). Hereinafter, the orientation direction of the material constituting each sheet 21, 22 is referred to as the MD (Machine Direction) direction, and the direction orthogonal to the MD direction is referred to as the TD (Transverse Direction) direction. The MD direction of each sheet 21, 22 is the direction along the standard width direction. The TD direction of each sheet 21, 22 is the direction along the standard height direction. An example of the material constituting the first adhesive layer 20D is a polyester-based adhesive. An example of the material constituting the second adhesive layer 20E is a polyester-based adhesive.

[0020] Regarding the bottom member sheet 23, the outermost layer 23A is made of the same material as the outermost layer 20A of the body member sheet 20, but an example of the material of the intermediate layer 23B is unstretched nylon without easy cutability.

[0021] The sealant layer 20C of the body member sheet 20 is excellent in heat resistance, heat sealability, and impact resistance. An example of the material constituting the sealant layer 20C is unstretched polypropylene (hereinafter referred to as "CPP").

[0022] Excellence in tearability in the MD direction means, for example, a case where the tearing force conforming to the trouser tear method defined in JIS standard K7128-1 is 1.2 N or less. In the trouser tear method, a 75-mm cut is made at the center of a rectangular test piece having a length of 50 mm in the TD direction and a length of 150 mm in the MD direction, and the tearing force in the MD direction is measured at a speed of 200 mm / min in a thermostatic chamber at 23°C.

[0023] [[ID= It has excellent bottom-opening properties. Furthermore, being an unstretched film, it stretches when pulled and is not easily cut.

[0024] 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.

[0025] The opening section 50 has a notch 51 on at least one of the sealing sections on the left and right sides. It is also desirable to provide a guide section 52 on the body member sheet 20 that guides the cutting of the body member sheet 20, at the same height as the notch 51 in the standard height direction, 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.

[0026] 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.

[0027] 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.

[0028] 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.

[0029] 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.

[0030] 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.

[0031] The steam passage section 60 can take various forms. In one example, the steam passage section 60 has a right side sealing section 33 and It is provided on at least one of the left side seal portion 34. In another example, the steam passage portion 60 is provided inside the seal portion, independently of the right side seal portion 33 and the left side seal portion 34. Figure 1 shows an example where it is provided only on the right side seal portion 33.

[0032] 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.

[0033] 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.

[0034] 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]

[0035] 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.

[0036] The meanings of the material terms shown in Table 1 are as follows:

[0037] <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> This polyethylene terephthalate film (12 μm thick) has excellent tear resistance in the MD direction and does not have perforations at the opening. Excellent tear resistance in the MD direction means, for example, that the tear force conforming to the trouser tearing method specified in JIS standard K7128-1 is 1.2 N or less. <Easy-cut Ny15> This polyamide film (15 μm thick) has excellent tear resistance in the MD direction and does not have perforations at the opening. <pet12> A polyethylene terephthalate film (thickness: 12 μm) that is not excellent in tearability in the MD direction and has no perforation processing at the opening part. Not being excellent in tearability in the MD direction means, for example, when the tearing force conforming to the trouser tear method defined in JIS standard K7128-1 is exceeding 1.2 N. <PET12 (with perforation processing)> A polyethylene terephthalate film (thickness: 12 μm) that is not excellent in tearability in the MD direction and has perforation processing at the opening part. <cpp60> An unoriented polypropylene film (60 μm thick) with poor tear resistance in the MD direction. <ny15> This is a polyamide film (15 μm thick) with poor tear resistance in the MD direction, and the opening is not perforated.

[0038] [Table 1]

[0039] As can be seen in Table 1, when the body sheet is not made of polyamide film but is made of an easy-to-cut material, or when perforations are applied to the opening, and the bottom sheet is made of polyamide, the best steam-permeable pouch with the best cutability and bottom opening suitability is obtained.

[0040] 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.

[0041] Furthermore, the body sheet does not use polyamide film and is made of a material with excellent tearability in the MD direction, or if perforations are applied to the opening, the body sheet can be easily and neatly torn by hand from the opening. Therefore, the contents can be easily removed from the opening. In addition, since the bottom sheet is made of a material containing polyamide film, it is flexible and has bottom opening properties, so a steam-permeable pouch with suitable filling properties can be provided. [Explanation of Symbols]

[0042] 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 a body sheet and a bottom sheet that is folded into the bottom surface. The left side, right side, and bottom surface of the body member sheet, as well as the peripheral edge with the bottom member sheet, are sealed to form a sealed area, and after filling with contents, the top surface of the body member sheet is sealed to create a storage space for containing 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 on the bottom side of the steam-permeable portion that is substantially parallel to the bottom surface, The opening section includes a guide section that guides the cutting of the body member sheet from the right end of the seal section on the left side to the left end of the seal section on the right side, The guide portion is provided between the steam passage portion and the bottom member sheet. The body member sheet and the bottom member sheet each consist of a laminate that includes at least an outermost layer and a sealant layer. The body sheet is made of a material that does not contain polyamide, and the bottom sheet is made of a material that contains polyamide. The outermost layer includes a transparent vapor-deposited layer, The body member sheet further includes an intermediate layer laminated between the outermost layer and the sealant layer, and the outermost layer and the intermediate layer are bonded together by an adhesive layer. The guide portion includes a plurality of notches formed in the intermediate layer, and the plurality of notches are formed discontinuously in the width direction of the steam-permeable pouch. The intermediate layer of the body member sheet is made of a polyethylene terephthalate film that is easily torn in the width direction of the steam-permeable pouch, the tear force of the polyethylene terephthalate film in the width direction of the steam-permeable pouch is 1.2 N or less, and the tear force is a value measured in accordance with the trouser tear method specified in JIS K 7128-1, for a steam-permeable pouch.

2. The steam-permeable pouch according to claim 1, further comprising an intermediate layer laminated between the outermost layer and the sealant layer.

3. The steam-permeable pouch according to claim 1 or 2, wherein the opening portion has a notch in at least one of the sealing portions on the left and right sides.

4. The steam passage portion is formed by a part of the sealing portion on the right side and has a shape that is recessed from the outside to the inside of the steam-permeable pouch. The steam-permeable pouch according to any one of claims 1 to 3, wherein the right end of the seal portion on the right side constitutes a part of the right end of the steam-permeable pouch.

5. The steam passage portion is formed by a part of the sealing portion on the left side and has a shape that is recessed from the outside to the inside of the steam-permeable pouch. The steam-permeable pouch according to any one of claims 1 to 3, wherein the left end of the seal portion on the left side constitutes a part of the left end of the steam-permeable pouch.

Images