Bag for microwave oven

Abstract

Provided is a pouch for a microwave oven that reliably and largely ensures the opening of a slit when a stove is heated. A pouch for a microwave oven (10) in which an automatic steam discharge mechanism (20) has a steam discharge seal portion (30), a slit (50), and a pouch cover sheet (41), the slit (50) is composed of a slit intermediate portion (52) that is formed toward a region closer to a seal peel start portion (31) than slit end portions (51), the automatic steam discharge mechanism (20) further has an unsealed portion (41) that is formed to cover the entire circumference of the slit (50), and a control seal portion (70) that is obtained by heat-welding a portion of the pouch cover sheet (41) to a second film (12).

Description

Technical Field

[0001] This invention relates to a microwave oven bag equipped with an automatic steam venting mechanism that automatically releases internal steam during heating. Background Technology

[0002] Previously, the following packaged foods were available on the market: cooked or semi-cooked foods were placed inside bags formed by thermally bonding overlapping films, and the food was heated and cooked in a microwave oven before consumption.

[0003] When heated in a microwave oven, the internal pressure of such a bag increases due to the steam generated by the food and the thermal expansion of the internal air. This can cause the bag to break or deform, and the food inside may scatter due to the bag breaking.

[0004] Therefore, it is known that in recent years, microwave oven bags have generally been equipped with an automatic steam venting mechanism that automatically releases internal steam during heating (for example, see Patent Document 1). One solution for such an automatic steam venting mechanism is... Figure 10 As shown, an automatic steam discharge mechanism is known, comprising: a steam discharge sealing portion 130 formed by thermally welding overlapping films 111 and 112, thereby isolating the steam release portion 140 inside from the contents receiving portion 114; and a slit 150 formed through the steam release portion 140 in the first film 111.

[0005] In Figure 10 In the automatic steam discharge mechanism 120 shown, when the pressure inside the contents container 114 increases due to heating by the microwave oven, a portion of the steam discharge seal 130 peels off, thereby connecting the contents container 114 with the steam release portion 140, and the steam inside the contents container 114 is discharged to the outside through the slit 150.

[0006] Existing technical documents

[0007] Patent documents

[0008] Patent Document 1: Japanese Patent Application Publication No. 2003-192042 Summary of the Invention

[0009] The problem that the invention aims to solve

[0010] However, in Figure 10In the automatic steam discharge mechanism 120 shown, depending on the expansion state of the bag during heating, it is sometimes impossible to ensure a sufficient opening size in the slit 150. Thus, if the opening of the slit 150 is small, the amount of steam discharged cannot be adequately ensured. Therefore, the bag may remain in an expanded state caused by steam for a long time, resulting in perforation of the bag due to thermal damage to the inner surface material of the bag.

[0011] Therefore, the present invention is an invention that solves these problems, and its object is to provide a microwave oven bag that can reliably and significantly ensure the opening of the slit when heated in a stove through a simple structure.

[0012] Technical solution

[0013] The present invention solves the above-mentioned problems by providing a microwave oven bag with an automatic steam venting mechanism, the automatic steam venting mechanism comprising: a steam venting seal formed by heat-welding overlapping first and second films, thereby isolating the steam release portion inside from the contents containing portion; a slit formed on the first film in the steam release portion; and a bag cover sheet formed on the first film, divided by the slit. The steam venting seal has a seal peeling start portion, which peels off upon heating by steam generated within the contents containing portion. The slit is composed of two ends and a middle portion, the middle portion being formed toward a region closer to the seal peeling start portion than the two ends of the slit, connecting the two ends of the slit. The automatic steam venting mechanism further comprises: an unsealed portion formed to cover the entire circumference of the slit, without welding the first and second films; and a control seal obtained by heat-welding a portion of the bag cover sheet formed on the first film to the second film.

[0014] Invention Effects

[0015] According to the present invention, the automatic steam discharge mechanism has an unsealed portion formed in a manner that covers the entire circumference of the slit and a control sealing portion obtained by thermally fusing a portion of a bag cover sheet formed on the first film to the second film. Thus, when the bag is heated by a microwave oven, when the steam discharge seal peels off and the contents containment portion communicates with the steam release portion, the first film and the second film tend to separate due to the increased pressure inside the bag on the side closer to the start of the seal peeling than the slit. On the side farther from the start of the seal peeling than the slit, i.e., the area where the bag cover sheet is formed, the first film and the second film are prevented from separating by the control sealing portion. Therefore, the opening of the slit can be reliably and extensively ensured, and steam discharge can be carried out well.

[0016] Furthermore, the unsealed portion is formed in a manner that covers the entire circumference of the slit, thereby enabling reliable separation between the first and second films by an increase in the internal pressure of the bag on the side closer to the start of the seal peeling than the slit. Attached Figure Description

[0017] Figure 1 This is an explanatory diagram showing a microwave oven bag according to the first embodiment of the present invention.

[0018] Figure 2 This is an explanatory diagram showing the automatic steam discharge mechanism as viewed from the first membrane side.

[0019] Figure 3 Therefore, from and Figure 2 This is an illustration of an automatic steam discharge mechanism, shown from the perspective of the second membrane side on the opposite side.

[0020] Figure 4 This is an explanatory diagram showing the automatic steam discharge mechanism when the bag is heated.

[0021] Figure 5 It is an explanatory diagram that illustrates the dimensions of each part.

[0022] Figure 6 This is an image showing a bag with a controlled seal being heated.

[0023] Figure 7 This image shows a situation where a bag without a controlled seal has been heated.

[0024] Figure 8 This is an explanatory diagram showing the automatic steam discharge mechanism of the second embodiment.

[0025] Figure 9 This is an explanatory diagram showing a modified example of an automatic steam discharge mechanism.

[0026] Figure 10 This is an explanatory diagram showing a conventional automatic steam discharge mechanism. Detailed Implementation

[0027] Hereinafter, the microwave oven bag 10 of the first embodiment of the present invention will be described with reference to the accompanying drawings.

[0028] First, such as Figure 1 As shown, the bag 10 is formed into a bag shape by forming a bag-making sealing part 13, and the contents containing part 14 inside contains food or other contents. The bag-making sealing part 13 is obtained by heat bonding an overlapping first film 11, a second film 12 (and a flap film) at a designated location.

[0029] If we were to provide a detailed description of the bag 10 in this embodiment, it would be as follows: Figure 1 As shown, the bag 10 is configured as a so-called upright bag in the shape of a bag by folding a first film 11 and a second film 12, which are continuously formed as a single film, at the top of the bag 10. At the bottom of the bag 10, a flap film (not shown) is placed between the first film 11 and the second film 12. The first film 11 and the second film 12 or the first film 11, the second film 12 and the flap film (not shown) are heat-fused together at the sides and bottom of the bag 10, thereby forming a bag-making sealing part 13 (side sealing parts 13a, 13b, bottom sealing part 13c).

[0030] like Figure 1 As shown, in the side sealing portions 13a and 13b, notches 15 for opening the bag 10 are formed above and opposite to the steam discharge sealing portion 30, which will be described later.

[0031] The bag 10 is provided with an automatic steam discharge mechanism 20 for automatically releasing the steam inside the bag 10 to the outside when heated.

[0032] like Figure 1 , Figure 2 As shown, the automatic steam discharge mechanism 20 includes: a steam discharge sealing part 30, which is formed by heat-welding overlapping a first film 11 and a second film 12, so that the steam release part 40 inside is isolated from the contents receiving part 14; a slit 50, which is formed on the first film 11 in the steam release part 40; and a flap 60, which is formed on the first film 11 and is divided by the slit 50.

[0033] The following is based on Figure 2 The components of the automatic steam discharge mechanism 20 are explained.

[0034] First, such as Figure 2 As shown, the steam discharge sealing part 30 is continuously formed on the inner side of the bag-making sealing part 13 and the bag-making sealing part 13 (side sealing part 13a).

[0035] The steam exhaust seal 30 has a seal peeling start portion 31, which begins to peel off due to steam generated in the contents receiving portion 14 during microwave heating (in such a way that the outer peripheral side of the steam exhaust seal 30 is in communication with the inner peripheral side). In this embodiment, as... Figure 1 , Figure 2 As shown, the seal peeling start part 31 is the part of the annular steam discharge seal part 30 that is closest to the center C of the contents receiving part 14.

[0036] like Figure 2As shown, the steam release section 40 is a part that is isolated from the contents containing section 14 by forming a steam discharge seal section 30. In this embodiment, the steam release section 40 is surrounded by the steam discharge seal section 30 and the bag making seal section 13 (side seal section 13a).

[0037] like Figure 2 As shown, the slit 50 is formed through the first film 11 in the film thickness direction. It is composed of a pair of slit ends 51 and a generally arc-shaped (generally C-shaped or generally U-shaped) slit middle portion 52. The slit middle portion 52 is formed toward the area closer to the sealing peel start portion 31 than the slit ends 51 (the side closer to the sealing peel start portion 31 than the virtual line passing through the pair of slit ends 51), and connects the slit ends 51.

[0038] It should be noted that, in this embodiment, the virtual line connecting the two ends 51 of the slit is along the longitudinal direction of the microwave oven bag 10. Figure 1 The positions of the two ends 51 of the slit are determined by extending in the vertical direction (parallel to the side sealing part 13a).

[0039] Furthermore, in the first embodiment, such as Figure 3 As shown, no slits are formed in the vapor release section 40 of the second film 12.

[0040] like Figure 2 As shown, the bag cover 60 is a portion that is partially separated from the periphery of the first film 11 by forming a slit 50.

[0041] The bag cover 60 has a connecting portion 61 at its outer periphery, away from the sealing peeling start portion 31, which is connected to the peripheral portion of the first film 11.

[0042] like Figure 2 As shown, the automatic steam discharge mechanism 20 also includes: an unsealed portion 41 formed to cover the entire circumference of the slit 50 in the steam release portion 40; and a control sealing portion 70 obtained by heat-welding a portion of the bag cover sheet 60 formed on the first film 11 to the second film 12.

[0043] Unsealed portion 41 is the area where the overlapping first film 11 and second film 12 have not been welded together, such as... Figure 2 As shown, when viewed from above, the unsealed portion 41 is formed in such a way that it completely covers the circumference of the slit 50 in the plane of the bag.

[0044] In this embodiment, the unsealed portion 41 is formed in such a way that it covers the entire area of ​​the vapor release portion 40 except for the forming portion of the control sealing portion 70.

[0045] The control sealing part 70 is a portion obtained by welding together overlapping first films 11 and second films 12, such as... Figure 2 As shown, the control sealing part 70 is continuously formed with the bag-making sealing part 13 (side sealing part 13a) in a transverse manner, protruding from the bag-making sealing part 13 (side sealing part 13a) toward the inside of the bag, and a portion of the bag cover sheet 60 is thermally fused to the second film 12 in a part of it (top part).

[0046] Next, the dimensions of each part are set as follows.

[0047] First, from the viewpoint of effectively utilizing the effect achieved by the control seal 70 (i.e., reliably and significantly ensuring the opening of the slit 50 by preventing separation between the first film 11 and the second film 12 through the control seal 70), such as Figure 5 As shown, preferably, the direction in which the slit 50 extends orthogonal to the virtual line connecting the two ends 51 of the slit (in other words, the direction in which the connecting portion 61 extends) is in the direction of the slit 50. Figure 1 , Figure 5 In the example shown, the distance γ between the innermost part (apex part) of the microwave oven bag 10 (horizontal direction) and the control sealing part 70 in the direction is set to 4 mm or less. Furthermore, more preferably, the distance γ is set to 3 mm or less.

[0048] Furthermore, from the viewpoint that the passage for suppressing steam formed between the peeling portion of the steam discharge seal 30 and the slit 50 closes again when the steam discharge seal 30 peels during bag heating, thus effectively discharging steam, as Figure 5 As shown, preferably, the direction in which the slit 50 extends orthogonal to the virtual line connecting the two ends 51 of the slit (in other words, the direction in which the connecting portion 61 extends) is in the direction of the slit 50. Figure 1 , Figure 5 In the example shown, the distance β between the innermost part (apex part) of the microwave oven bag 10 (in the left-right direction of the attached figure) and the steam exhaust seal 30 is set to 4 mm or less. More preferably, the distance β is set to 3 mm or less.

[0049] Furthermore, from the viewpoint of ensuring a larger opening of the slit 50 during bag heating, such as Figure 5 As shown, it is preferable to set the distance σ between the two ends 51 of the slit to 5 mm or more; more preferably, the distance σ is set to 7 mm to 10 mm or less.

[0050] Next, the following describes the situation of each part when the bag 10 of this embodiment is heated.

[0051] First, when the bag 10 is heated in a microwave oven, the internal pressure of the bag 10 increases due to the steam generated by the contents such as food and the thermal expansion of the internal air. This pressure then rises from the center C of the contents-containing section 14 (see reference). Figure 1 The force is applied radially.

[0052] Next, by means of a radially spreading force, the steam discharge seal 30 begins to peel off from the area near the center C of the contents receiving portion 14 (the seal peeling start portion 31), and the peeling of the steam discharge seal 30 proceeds in a direction away from the center C of the contents receiving portion 14.

[0053] Furthermore, when the steam discharge seal 30 is being peeled off, the unsealed portion 41 of the steam release portion 40 is also being peeled off in the same direction away from the center C of the contents receiving portion 14.

[0054] That is, in the unsealed portion 41 of the vapor release portion 40, the first film 11 and the second film 12 are in a state of close contact with each other before the peeling of the vapor release seal portion 30 begins, but after the peeling of the vapor release seal portion 30 begins, the peeling proceeds in a direction away from the center C of the contents receiving portion 14 by the aforementioned radially diffused force.

[0055] Next, when the separation between the first film 11 and the second film 12 in the steam discharge sealing part 30 and the unsealed part 41 reaches the position of the slit 50, the steam in the contents containing part 14 is released to the outside of the bag 10 through the slit 50.

[0056] At this time, on the side closer to the sealing peeling start part 31 than the slit 50 ( Figure 4 In area A shown, the first film 11 and the second film 12 are to be separated by the internal pressure inside the bag 10, and the bag cover 60 is formed on the side farther from the sealing peeling start portion 31 than the slit 50. Figure 4 In region B (as shown), the first film 11 and the second film 12 are prevented from separating by a sealing part 70. Therefore, with the slit 50 as the boundary, the first film 11 in region A and the first film 11 in region B are significantly separated in the bag's inner and outer directions. As a result, as Figure 6 As shown, the slit 50mm can ensure a relatively large opening, thus ensuring sufficient steam discharge. Therefore, the internal pressure of the bag can be maintained at 1.10 kgf / cm² after the bag has been microwaved and steam begins to escape (after steam release). 2 With such low internal pressure, there is no longer a possibility of the bag breaking.

[0057] It should be noted that, in Figure 7 In the example, as a comparison, it is shown that... Figure 10The example shown is a case where a bag without a controlled seal 70 has been heated, meaning that a sufficiently large opening cannot be ensured at the slit 150. In such cases... Figure 7 As shown, if the slit opening of 150° cannot be guaranteed to be sufficiently large, the amount of steam released cannot be adequately ensured. Therefore, the internal pressure of the bag after steam release tends to become greater than 1.10 kgf / cm². 2 The higher the temperature, the greater the chance of the bag breaking.

[0058] Furthermore, at this time, the unsealed portion 41 is formed in a manner that covers the entire circumference of the slit 50, so that it can be located closer to the sealing peeling start portion 31 than the slit 50. Figure 4 The area A shown enables reliable separation between the first film 11 and the second film 12.

[0059] Next, based on Figure 8 The microwave oven bag 10 according to the second embodiment of the present invention will be described. Here, in the second embodiment, the components other than some components are exactly the same as those in the first embodiment described above, therefore, the description of the components other than the differences is omitted.

[0060] It should be noted that, Figure 8 (a) is an explanatory diagram showing the bag 10 of the second embodiment as viewed from the side of the first film 11. Figure 8 (b) is from and Figure 8 (a) An explanatory diagram showing the way the second film 12 is viewed from the opposite side of the bag 10.

[0061] First, in the first embodiment described above, as Figure 2 , Figure 3 As shown, it has been described that in the vapor release section 40, the slit 50 is formed only in the first film 11 and no slit is formed in the second film 12. However, in the second embodiment, as... Figure 8 As shown, in the vapor release section 40, a slit (second slit 53) is also formed in the second film 12.

[0062] That is, in the second embodiment, such as Figure 8 As shown, a second slit 53 is formed on the second film 12. The second slit 53 is formed in such a way that it completely overlaps with the slit 50 formed on the first film 11 in the inside-out direction, and is formed in the same shape and at the same position as the slit 50 formed on the first film 11.

[0063] The second slit 53 formed in the second thin film 12 is formed in the same way as the slit 50 formed in the first thin film 11, by penetrating the second thin film 12 in the thickness direction, such as... Figure 8As shown in (b), the second slit 53 is composed of two ends 54 of the slit and a generally arc-shaped (generally C-shaped or generally U-shaped) middle portion 55 of the slit, which is formed toward a region closer to the sealing peeling start portion 31 than the two ends 54 of the slit, and connects the two ends 54 of the slit.

[0064] Furthermore, in the second embodiment, such as Figure 8 As shown in (b), similarly to the bag cover 60 formed on the first film 11, a second bag cover 62 is also formed on the second film 12.

[0065] like Figure 8 As shown in (b), the second bag cover 62 is located at the part where the vapor release portion 40 is partially separated from the peripheral portion of the second film 12 by forming a second slit 53, and has a connecting portion 63 at its outer periphery away from the sealing peeling start portion 31, which is connected to the peripheral portion of the second film 12.

[0066] In the second embodiment, a portion of the bag cover sheet 60 formed on the first film 11 is thermally fused to a portion of the second bag cover sheet 62 formed on the second film 12 via the control sealing portion 70.

[0067] In the bag 10 obtained in the second embodiment, a second slit 53 is also formed on the second film 12. Therefore, even if the bag 10 is placed inside a microwave oven with the first film 11 side facing down, where steam cannot be emitted from the slit 50 formed on the first film 11 alone, steam can be discharged from the second slit 53 formed on the second film 12, thus improving the reliability of steam discharge. Furthermore, compared to the case where the slit 50 is formed only on the first film 11, the slits 50 and 53 can be formed in one step after the first film 11 and the second film 12 are welded together to form the steam discharge seal 30. Therefore, the slits 50 and 53 can be reliably positioned at predetermined locations within the steam discharge seal 30.

[0068] The embodiments of the present invention have been described in detail above, but the present invention is not limited to the above embodiments, and various design changes can be made without departing from the present invention as described in the claims.

[0069] For example, the various components of the above-described multiple embodiments and variations can be arbitrarily combined to construct bag 10.

[0070] Furthermore, the specific design of each film constituting the bag 10 (first film 11, second film 12, and flap film) can be any known synthetic resin film, such as polyester, polypropylene, polyamide, etc., coated films or vapor-deposited films that impart gas barrier or water barrier properties to these synthetic resin films, or films formed by laminating paper or aluminum foil on the synthetic resin film.

[0071] Furthermore, in the above embodiment, the bag 10 is described as a so-called upright bag, but the specific design of the bag 10 is as long as it has an overlapping arrangement of the first film 11 and the second film 12, or it can be any bag such as a bag in which no flap film is arranged between the first film 11 and the second film 12.

[0072] Furthermore, in the above embodiment, the first film 11 and the second film 12 are described as being integrally formed as a single film, but the first film 11 and the second film 12 may also be formed separately.

[0073] Furthermore, in the above embodiments, the contents of bag 10 are described as food, but the specific contents are not limited to food.

[0074] Furthermore, in the above embodiment, the steam exhaust seal 30 and the bag-making seal 13 (side seal 13a) are continuously formed and described, but the specific design of the steam exhaust seal 30 is not limited to the above design, and may also be as follows: Figure 9 As shown in (a), it is independently formed on the inside of the sealing part 13 for bag making.

[0075] Furthermore, as a variation of the steam discharge seal 30, the strength of the peel resistance (resistance to the communication between the outer and inner peripheral sides of the steam discharge seal 30 that is achieved by peeling) can be assigned to each part of the steam discharge seal 30. For example, strong sealing parts and weak sealing parts with different peel resistance can be formed in the steam discharge seal 30, thereby adjusting the position of the seal peeling start part 31 that begins to peel due to the steam generated in the contents containing part 14 when heated in a microwave oven.

[0076] Furthermore, in the above embodiment, the control sealing part 70 and the bag-making sealing part 13 are described as being continuously formed, but the specific design of the control sealing part 70 is not limited to the above design, and may also be as follows: Figure 9 As shown in (b), the control seal 70 is formed to point-seal a portion of the bag cap 60 to the second film 12 at a position independent of the bag-making seal 13.

[0077] Furthermore, in the above-described embodiment, the slit middle portion 52 of the slit 50 is formed in a generally arc shape (generally C-shaped or generally U-shaped) and has been described. However, the slit middle portion 52 can be formed from both ends 51 of the slit toward the area closer to the sealing peeling start portion 31 and connected to both ends 51 of the slit. It can also be any slit middle portion, for example, the slit middle portion 52 can be formed by multiple straight lines or curves into a V-shape, "コ" shape or the like.

[0078] Furthermore, in the above embodiment, the slit 50 is described as a linear cut (a cut without width), but the specific design of the slit 50 is not limited to this. The slit 50 may also be formed with a predetermined width (width in a direction orthogonal to the extension direction of the slit 50).

[0079] Explanation of reference numerals in the attached figures

[0080] 10: Bags (microwave oven bags);

[0081] 11: First thin film;

[0082] 12: Second thin film;

[0083] 13: Sealing part for bag making;

[0084] 13a: Side sealing part;

[0085] 13b: Side sealing part;

[0086] 13c: Bottom sealing part;

[0087] 14: Contents container;

[0088] 15: Gap;

[0089] 20: Automatic steam exhaust mechanism;

[0090] 30: Steam discharge sealing section;

[0091] 31: Sealing peeling start part;

[0092] 40: Steam release section;

[0093] 41: Unsealed section;

[0094] 50: Slit;

[0095] 51: The two ends of the slit;

[0096] 52: The middle part of the slit;

[0097] 53: Second slit;

[0098] 54: The two ends of the slit;

[0099] 55: The middle part of the slit;

[0100] 60: Bag lid piece;

[0101] 61: Connecting part;

[0102] 62: Second bag lid;

[0103] 63: Connecting part;

[0104] 70: Control sealing part;

[0105] C: The center of the contents-containing section.

Claims

1. A microwave oven bag, comprising an automatic steam venting mechanism, characterized in that, The microwave oven bag is formed into a bag shape by heat-sealing a first film and a second film to create a sealing part for bag making. The automatic steam discharge mechanism includes: a steam discharge sealing portion formed by heat-welding overlapping first and second films, separating the inner steam release portion from the contents receiving portion; a slit formed in the first film at the steam release portion; and a bag cover sheet formed in the first film, divided by the slit. The steam exhaust seal is continuously formed with the bag-making seal. The steam discharge seal has a seal peeling initiation section, which initiates peeling by steam generated within the contents containment section during heating. The slit is composed of two ends and a middle portion, with the middle portion forming a region closer to the sealing peeling start than the two ends, and connecting the two ends of the slit. The automatic steam discharge mechanism also includes: an unsealed portion formed to cover the entire circumference of the slit, which does not weld the first film and the second film; and a control sealing portion obtained by thermally fusing a portion of the bag cover formed on the first film to the second film. The control sealing portion is formed to protrude from the bag-making sealing portion toward the inside of the bag.

2. The microwave oven bag according to claim 1, characterized in that, A second slit is formed in the second film, and the second slit in the vapor release section is formed in the same shape as the slit formed in the first film in the inward direction and is formed in the same position as the slit formed in the first film.

Images