Packaging bags

Abstract

To provide a packaging bag capable of also serving as tableware by easily forming an opening of a relatively large opening width in a longitudinal direction of the packaging bag, which is even steam-permeable in microwave oven cooking, and from which contents are easily taken out by making an opened opening piece cuttable even when using a sealant exhibiting a difficult opening holding property due to too strong stiffness strength.SOLUTION: The packaging bag comprises cylindrical structure made from a laminate comprising a substrate strongly stretched in a vertical direction, and a heat-sealable resin layer as an innermost layer. The entire back-pasting seal part is subjected to fragile processing A for opening. Further, one opening notch is provided at an upper portion of the back-pasting seal part. An opening piece after opening thereof can be cut away from a fragile processing A portion of the back-pasting seal part.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a packaging bag made of a laminated film and having a back-sealed shape, and in particular to a packaging bag that can be used as tableware and also allows steam to pass through, by neatly forming a large opening in the packaging bag when removing the contents after microwave cooking. [Background technology]

[0002] Conventionally, cooked or semi-cooked foods are known to be stored at room temperature, low temperature, or frozen in a packaging container such as a packaging bag, and then heated in a microwave oven without opening the bag to make them edible. Several packaging bags for the above-mentioned uses are known. Generally, all of them are made using a laminated film. Some packaging bags are designed to prevent bursting by creating a tear in the laminated film when the internal pressure increases during heating in a microwave oven, allowing water vapor to escape through the tear.

[0003] After cooking in a microwave oven, the contents must be transferred to a separate container such as a plate in order to be consumed, but the packaging bag is also hot after heating in the microwave, so if care is not taken there is a risk of being burned or dropping the bag, and it is also troublesome to have to prepare a separate plate. Therefore, a packaging bag has been proposed that uses the packaging bag as it is after cooking, but has a large opening that allows the contents to be consumed directly.

[0004] For example, Patent Document 1 discloses a packaging bag in which a pair of left and right tear-off guide lines are provided on the laminate forming the packaging bag along the intended opening portion, from near the tear-off notch to the bottom end of the packaging bag. It cites methods such as die cutting and laser processing as examples of methods for providing the tear-off guide lines, and claims that it is possible to provide an opening with a large opening width. However, the packaging bag disclosed in Patent Document 1 has the following issues when providing the tear-off guide lines. Specifically, the half-cutting process using laser processing requires processing across almost the entire area in the flow direction of the product, which is extremely time-consuming and not suitable for mass production. Furthermore, with blade processing such as a rotary die cutter, half-cutting, especially on thin-gauge film, is difficult due to the blade height accuracy, which also limits mass production. Furthermore, no consideration is given to microwave cooking suitability.

[0005] Patent Document 2 discloses a packaging bag made of a laminated film that is easily tearable in the vertical direction and that stores vertically extending contents. However, the opening guide line, which runs horizontally, is inserted from the spine seal area near the notch. If the laser processing and the notch are misaligned in the flow direction due to the precision of the filling machine, the bag cannot be opened. Furthermore, the physical properties of the sealant are not specified, and no consideration is given to hand tearability or steam permeability when heated in a microwave oven. Furthermore, if the laminated film that is folded over when opened has a high stiffness, it will return to cover the opening, making it impossible to remove the contents.

[0006] Furthermore, in Patent Document 3, C4-LLDPE (Ziegler-Natta catalyst) is used as a sealant from the viewpoint of ease of hand tearing and suitability for steam passage, but the tension is too strong, making it somewhat difficult to maintain an opening, and it is necessary to set the opening size to a / b<1. [Prior art documents] [Patent documents]

[0007] [Patent Document 1] Japanese Patent Application Laid-Open No. 2015-123967 [Patent Document 2] Patent No. 6255830 [Patent Document 3] Japanese Patent Publication No. 2022-57393 Summary of the Invention [Problem to be solved by the invention]

[0008] To provide a packaging bag which can be used as tableware by easily forming an opening with a comparatively large opening width in the longitudinal direction of the packaging bag, and which can also pass steam in microwave cooking, and which can facilitate removal of contents by making it possible to cut off an opened tear-off piece even when a sealant having too much stiffness and difficulty in maintaining the opening is used. [Means for solving the problem]

[0009] In order to solve the above problems, a first aspect of the present invention is a packaging bag having a tubular structure in which both side edges of a packaging material made of a laminate having a base material strongly stretched in the longitudinal direction and a heat-sealable resin layer as the innermost layer are heat-sealed in a folded state to form a spine seal part in the longitudinal direction, and the spine seal part is entirely subjected to a frangible processing A for opening, and further, a tear notch is provided at one location at the top of the spine seal part, which serves as a trigger for opening, and the packaging material forming the body part is provided with a left hand groove for capturing and guiding a tear starting from the tear notch when opening. A pair of opening guide lines are provided on the right, and the opening guide lines are cut lines formed by weakening processing B that do not penetrate the packaging material, and are formed symmetrically with the base line of the back seal part as the center line, and start from a starting point provided near the opening notch, spread out in the approximate left and right width direction of the packaging bag, and end at a curved end in the flow direction, and from the end point onwards, the opening lines are extended in the vertical direction due to the vertical straight cutting ability of the base material, and after opening, the opening piece can be cut off from the weakening processing A part of the back seal part.

[0010] In a second aspect of the present invention, the heat-sealable resin layer may be polyethylene copolymerized with C4 (butene-1) as a comonomer using a Ziegler-Natta catalyst.

[0011] In addition, in a third aspect of the present invention, the opening guide line may be a continuous line, a broken line, a dotted line, or a combination thereof formed by laser processing.

[0012] In a fourth aspect of the present invention, the opening guide line may not penetrate the heat-sealable resin layer. When the opening guide line is formed by laser processing, it is possible to selectively cut only a specific layer by combining the wavelength of the laser with the layer structure of the laminate.

[0013] In addition, in a fifth aspect of the present invention, the direction in which the packaging material is prone to tearing is the width direction (TD direction), and the starting point of the opening guide line may be located above a line extending from the tip of the opening notch.

[0014] In addition, in a sixth aspect of the present invention, the direction in which the packaging material is prone to tearing is the machine direction (MD direction), and the starting point of the opening guide line may be located below a line extending from the tip of the opening notch. [Effects of the Invention]

[0015] According to the packaging bag of the present invention, by combining half-cut processing by laser processing with a uniaxially stretched substrate, it is possible to obtain a packaging bag that can be opened with a large opening area without excessively slowing down the processing speed, and that is suitable for mass production. In addition, since a large opening area can be secured, the bag can also be used as tableware, improving convenience when placing meals or sweets on it and eating them.

[0016] Furthermore, when a heat-sealable resin layer that serves as a sealant is selected, it is possible to make the steam permeability during microwave cooking more suitable.

[0017] Furthermore, even if a sealant is used that has too much stiffness and makes it difficult to keep the opening open, by making the opening strip detachable, it is possible to prevent the opened film from returning to the opening surface, thereby improving the usability of the tableware. [Brief explanation of the drawings]

[0018] [Figure 1] 1 is a schematic plan view of one embodiment of the packaging bag of the present invention. [Figure 2] FIG. 10 is a schematic plan view showing another example of the opening guide line. [Figure 3] 1A and 1B are perspective views showing a forming step of the weakening process A and an enlarged view of the weakening process A. FIG. [Figure 4] 1 is a schematic view showing an appearance of a packaging bag containing contents being opened; FIG. [Figure 5] FIG. 1 is a schematic view showing the appearance of a packaging bag containing contents when the bag is opened wide. [Figure 6] FIG. 10 is a schematic view showing an appearance of cutting off the opened tear strip. DETAILED DESCRIPTION OF THE INVENTION

[0019] Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. Note that the present invention is not limited to the embodiments described below. Furthermore, in the embodiments shown below, technically preferable limitations are imposed for carrying out the invention, but these limitations are not essential requirements for the present invention.

[0020] Figure 1 is a schematic plan view of one embodiment of the packaging bag of the present invention. The packaging bag 1 of the present invention is a tubular packaging bag in which both side edges of a packaging material 2 made of a laminate having a base material strongly stretched in the longitudinal direction (referred to as MD in the figure), which is also the flow direction in the manufacturing process, and a heat-sealable resin layer as the innermost layer, are heat-sealed in a palm-on-palm manner to form a spine seal portion 3 in the longitudinal direction. Because the base material is strongly stretched in the longitudinal direction, it is prone to tearing in the longitudinal direction.

[0021] A tearing notch 4, which serves as a trigger for opening, is provided at the upper end 3b of the spine seal portion 3. After the contents are placed inside, both vertical ends are flattened and sealed to form an upper seal portion 6a and a lower seal portion 6b, thereby sealing the packaging bag 1. In Fig. 1, the spine seal portion 3 is shown leaning to the left, but it can be leaned to either side.

[0022] In the present invention, even when a sealant with too high stiffness is used, making it difficult to maintain an open bag, the entire spine seal portion 3 is subjected to a weakening process A to enable the tear-off strip to be torn off. One example of this weakening process A is a process in which a film is sandwiched between a receiving roller and a blade entrance roller during a printing process prior to bag production, forming a continuous strip of micropores. This process creates micropores that completely penetrate one layer of the surface substrate but do not penetrate to the inner layer, such as the sealant. This results in the spine seal portion 3 having a moderate degree of easy peelability. By applying this weakening process A to the entire spine seal portion 3, the tear-off strip can be torn off from any position after the bag is opened.

[0023] Figure 3 is a perspective view showing the process of forming the weakening process A in the spine seal section 3, and an enlarged view of the weakening process A. When the roll film is rotated while the blade entrance roller is pressed against the surface of the roll film, the perforations on the blade entrance roller form micropores 10 on the surface of the film sheet as the film sheet is fed from the roll film. Because the micropores 10 are formed in a linear band, there is no need for highly accurate positioning in the linear direction. Furthermore, the continuous formation process is more efficient in terms of production than punching, etc., so the processing speed does not slow down significantly and it is also suitable for mass production.

[0024] Other examples of the weakening process A include Magic Cut (registered trademark) and Notchnon (registered trademark) which are scratched.

[0025] As shown in FIG. 1, a pair of left and right opening guide lines 5 are provided on the surface of the packaging material 2 that forms the body, on which the back seal portion 3 is formed, which start near the opening notch 4 and proceed in the left and right width direction of the packaging material 2, in order to capture and guide any tears in the packaging material.

[0026] The opening guide line 5 is a cut line formed by the weakening process B that does not penetrate the packaging material 2, and is formed symmetrically with the base line 3a, which is the base of the back seal portion 3, as the center line, and starts from a starting point s provided near the opening notch 4, proceeds diagonally downward, spreads diagonally downward in the left and right width direction of the packaging bag from the spreading starting point s2, and reaches an end point e provided on the left and right side edges of the packaging bag. The end point e is located below the opening notch 4.

[0027] The opening guide line 5 may be any cut line that does not penetrate the packaging material 2, and may be formed by a method using a blade such as a die cutter or rotary die cutter, or by a method using a laser processing machine such as a carbon dioxide laser. When the opening guide line 5 is formed by laser processing, it is possible to selectively cut only a specific layer by combining the wavelength of the laser with the layer structure of the laminate.

[0028] The opening guide line 5 may be formed from the front side or the back side of the packaging material 2, but if it is formed from the front side of the packaging material using a laser processing machine and left without penetrating the innermost heat-sealable resin layer, a product of stable quality can be obtained.

[0029] The shape of the opening guide line 5 may be, as shown in Fig. 1, a shape that starts from a starting point s, proceeds diagonally downward, spreads outward in the left-right width direction and diagonally downward from the spreading starting point s2, curves downward to the end point e, or a shape that proceeds diagonally downward from the starting point s, spreads outward in the left-right width direction and diagonally downward from the spreading starting point s2, and curves downward to the end point e. However, a shape that curves downward near the end point is more preferable because it makes it easier for the tear to progress vertically.

[0030] The opening guide line 5 may be a continuous line or a broken line as shown in Fig. 2. Although not particularly shown, it may also be a dotted line or a combination of these.

[0031] The opening guide line 5 is preferably spaced apart from the line extending from the tip of the opening notch 4, but has a starting point s near the opening notch 4. In the process of manufacturing the packaging bag, the laser processing step and the step of providing the opening notch 4 are separate steps, so even if the pitch of each processing step is slightly different and the position of the starting point s relative to the opening notch 4 is slightly shifted, there is no risk that the tearing connection from the opening notch 4 to the opening guide line 5 will not be possible, and tearing will not be hindered.

[0032] Regarding the positional relationship between the tearing notch 4 and the starting point s of the tearing guide line, if the packaging material is easily torn in the width direction (TD direction), it is preferable to position the starting point s above the tearing notch 4.

[0033] Conversely, if the packaging material is easily torn in the machine direction (MD), it is preferable to position the start point s below the tear notch 4 as shown in FIGS.

[0034] Next, the material used for the packaging bag 1 according to the present invention will be described. The layer structure of the laminate constituting the packaging material 2 is a base material made of a film strongly stretched in the longitudinal direction, and a heat-sealable film as the innermost layer. There are no particular limitations on the composition other than the resin layer. The most basic layer structure is a base film / heat-sealable resin layer. However, an adhesive layer for bonding these together, a printed layer, etc. may also be included.

[0035] Layers that can be added to the above two layers include a gas barrier layer, an intermediate layer, etc. For special applications, a light-shielding layer, an ultraviolet absorbing layer, etc. may be added. In some cases, the base layer also serves as a gas barrier layer.

[0036] As the base film, a polyethylene terephthalate resin film (PET), an oriented film such as an oriented polypropylene resin film (OPP), or an oriented nylon film (ONy) is usually used in consideration of printability.

[0037] The gas barrier layer may be made of aluminum foil, aluminum vapor-deposited film, metal oxide vapor-deposited film, various gas barrier resin films, or the like.

[0038] Polyolefin resins such as polyethylene resin and polypropylene resin are commonly used as the heat-sealable resin layer (sealant), but in the case of the packaging bag of the present invention, polyethylene copolymerized with a Ziegler-Natta catalyst using C4 (butene-1) as a comonomer is particularly preferred because it is easy to tear by hand and, when heated in a microwave oven, the internal pressure causes the opening guide line 5, which may be a continuous line, a dashed line, a dotted line, or a combination thereof, to partially break and open, resulting in a packaging bag with more appropriate vapor permeability that functions as a steam releaser. The heat-sealable resin layer may be formed by melting the resin and extruding it onto the base layer and laminating it, or it may be formed into a film and then laminating it.

[0039] Furthermore, if the tear strip is cut off, the heat-sealable resin layer can be made easily peelable to facilitate removal of the tear strip. Various types of films of such easily peelable heat-sealable resins (easy-peel sealants) are commercially available from various companies, and an appropriate one can be selected and used depending on the required performance.

[0040] As described above, when opening the bag, the bag can be torn from the end of the opening guide line 5 in a direction parallel to the back seal portion 3, forming a large opening in the packaging bag 1. This allows the user to use the packaging bag 1 as a tableware and directly consume the contents.

[0041] Next, the manner in which the packaging bag 1 is opened will be specifically described with reference to FIGS. After cooking in the microwave oven, the removed packaging bag is grasped by the back seal portions 3c and 3d on both sides of the tearing notch 4 and pulled in the direction of the arrow, as shown in Figure 4, to break the back seal portion 3 from the tip of the tearing notch 4, and then the packaging material 2 is broken and connected to the tearing guide line 5, and by breaking the tearing guide line 5, an opening 8 is formed in the packaging bag.

[0042] After the tearing of the opening guide line 5 reaches the end point e, if the back seal portion 3c is pulled further toward the bottom seal portion 6b, the packaging material 2 will tear further in the vertical direction because it is prone to tearing in the vertical direction, and a large opening 9 can be formed as shown in Figure 5.

[0043] As described above, in the case of the packaging bag of the present invention, from the viewpoint of hand-tearability and steam-permeability, the heat-sealable resin layer uses polyethylene copolymerized with a Ziegler-Natta catalyst using C4 (butene-1) as a comonomer, but the stiffness is too strong, making it somewhat difficult to keep the bag open. When the bag is opened by hand from the notch in the back seal portion 3, after opening along the opening guide line 5, the opening strip opens linearly from the end point in a direction almost horizontal to the flow direction, and when the hand is released from the opening strip, the film returns to the opening, preventing the content 12 from being taken in.

[0044] Therefore, in the case of the packaging bag according to the present invention, even if a sealant that has too much stiffness and therefore has difficulty in maintaining an opening is used, weakening treatment A is applied to the entire back seal portion 3 so that the opened tear strip can be cut off. When the film returns to the opening as described above, in order to cut off the torn tear strip 13, any part of the back seal portion 3 located near the bottom end of the tear strip 13 is picked up with the fingers of both hands and torn upward (or downward), the cut reaches the end f of the tear strip, and the tear strip can be separated from the packaging bag. Therefore, the tear strip 13 will not return to the opening 9 side, and there is no problem in consuming the contents 12. [Example]

[0045] The following describes the results of evaluations of various packaging bag samples that were prepared. Example 1 (Sample preparation) A laminate was created with the following layer structure (numbers indicate thickness). Uniaxially oriented nylon (Ny) (Uniathlon) 15 μm / / LLDPE (KF101, Skyfilm) 40 μm. The laminate was pasted together at the back seal to form a tube, one end of the tube was sealed flat, and the other end was used as an insertion opening for the contents. - An I-notch (straight cut) has been made in the designated position on the back sticker. A carbon dioxide laser was irradiated from the outer film side on the surface of the back seal portion of the laminate, forming a weakened processing line B in the shape shown in Figure 1, which did not penetrate the inner film. -Weak processing A (cut processing) is applied to the back sticker part. A pillow packaging bag with a width of 50 mm (a) and a flow direction of 70 mm (b) was made from the above laminate, and 200 g of frozen fried rice was placed inside. The opening was sealed to create a sample.

[0046] <Example 2> A sample was prepared in the same manner as in Example 1, except that the laminate was prepared with the following layer structure. Uniaxially stretched Ny (Uniathlon) 15 μm / / LLDPE (XMTN, Futamura) 40 μm.

[0047] Example 3 A sample was prepared in the same manner as in Example 1, except that a pillow packaging bag with a width direction length a: 80 mm and a flow direction length b: 70 mm was prepared.

[0048] Example 4 A sample was prepared in the same manner as in Example 2, except that a pillow packaging bag with a width direction length a: 80 mm and a flow direction length b: 70 mm was prepared.

[0049] <Comparative Example 1> The laminate was created with the following layer structure: Uniaxially oriented PET (Emblet PC) 12 μm / / LLDPE (KF101) 40 μm. A sample was prepared in the same manner as in Example 1, except that the weakening process A (breaking process) was not performed on the back seal.

[0050] <Comparative Example 2> The laminate was created with the following layer structure: Uniaxially oriented PET (Emblet PC) 12 μm / / LLDPE (XMTN) 40 μm. Samples were prepared in the same manner as in Example 2, except that the back seal was not subjected to weakening process A (breaking process).

[0051] <Comparative Example 3> A sample was prepared in the same manner as in Comparative Example 1, except that a pillow packaging bag with a width direction length a: 80 mm and a flow direction length b: 70 mm was prepared.

[0052] <Comparative Example 4> A sample was prepared in the same manner as in Comparative Example 2, except that a pillow packaging bag with a width direction length a: 80 mm and a flow direction length b: 70 mm was prepared.

[0053] (Cooking conditions) Examples 1 to 4 and Comparative Examples 1 to 4 were heated in a microwave oven at 1000W for 3 minutes. (Evaluation content) - Opening retention: When the hand is removed from the opening, if the film does not return to the opening and there is enough opening area to remove the contents, it is rated as 'Good'; if the film returns to the opening and gets in the way, making it impossible to remove the contents, it is rated as 'Bad'. The results are summarized in Table 1.

[0054] [Table 1]

[0055] In Examples 1 to 4, large openings could be formed. Furthermore, when the heat-sealable resin layer was made as specified, both good opening properties and vapor permeability were obtained. Even with sealants that had difficulty in maintaining an opening due to excessive longitudinal stiffness, good opening properties were achieved by cutting off the opening strip, even when the opening size was a / b > 1. In the comparative example, by restricting the opening size to a / b<1, the film did not return to the opening, ensuring sufficient opening area for removing the contents. However, when the above restriction was not met, the film returned to the opening, causing a hindrance and making it impossible to remove the contents. [Explanation of symbols]

[0056] 1...Packaging bag 2...Packaging material 3. Back sticker 4. Opening notch 5. Opening guide line 6a Upper end seal 6b Bottom seal 8,9... Opening 10...Micropore 12·Contents 13...Opening piece s···Start point of opening guidance line e End point of opening guide line f... Opening end

Claims

1. A packaging bag having a tubular structure in which both side edges of a packaging material made of a laminate having a base material strongly stretched in the longitudinal direction and a heat-sealable resin layer as the innermost layer are heat-sealed in a folded state to form a spine seal portion in the longitudinal direction, wherein the entire spine seal portion is subjected to a frangible processing A for opening, and further, a tear notch is provided at an upper part of the spine seal portion, which serves as a trigger for opening, and the packaging material forming the body portion is provided with a pair of left and right opening guide lines for capturing and guiding a tear starting from the tear notch when opening, the opening guide lines are cut lines formed by frangible processing B, and are formed symmetrically with the base line of the spine seal portion as the center line, and start from a starting point provided near the tear notch, extend in the substantially left and right width direction of the packaging bag, and end at a shape that curves in the flow direction, and from the end point, the opening line is extended in the longitudinal direction due to the linear cutting ability of the base material in the longitudinal direction, The start point of the opening guide line is located above a line extending from the tip of the opening notch, A packaging bag characterized in that the end point of the opening guide line is located closer to the start point than halfway along the length of the body portion in the vertical direction.

2. 2. The packaging bag according to claim 1, wherein the heat-sealable resin layer is polyethylene copolymerized with C4 (butene-1) as a comonomer using a Ziegler-Natta catalyst.

3. 3. The packaging bag according to claim 1, wherein the opening guide line is a continuous line, a broken line, a dotted line, or a combination thereof, formed by laser processing.

4. 4. The packaging bag according to claim 1, wherein the opening guide line does not penetrate the heat-sealable resin layer.

5. 5. The packaging bag according to claim 1, which is used for cooking.

Images