Packaging bags

Abstract

To provide a sealable packaging bag which can absorb an oil content and a water content of a content, and which has an automatic steam vent mechanism when heating the content by a microwave oven.SOLUTION: In a sealable packaging bag which stores a content inside and which is constituted by bag-making a laminate, the laminate is constituted at least from a base material layer comprising a plastic film, a hiding layer, an olefin resin intermediate layer, a paper or non-woven fabric layer, and an olefin resin layer of the innermost layer, in this order from the outside. In the laminate, scratch processing A for venting steam, and scratch processing B for absorbing water and absorbing oil are provided. The scratch processing A comprises scratch processing penetrating both of the base material layer comprising a plastic film and the hiding layer and scratch processing to the paper or non-woven fabric layer, and the scratch processing B comprises scratch processing penetrating both of the paper or non-woven fabric layer and the olefin resin layer of the inner most layer.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present invention relates to a packaging material, and more particularly to a packaging bag made of a laminate using a plastic film as a base material, for use in food packaging and the like. [Background technology]

[0002] Packaging bags, a type of packaging material, are widely used and are made of simple or laminated plastic film as a base material. They come in a variety of shapes and are used for a wide range of purposes, making them an indispensable part of modern life.

[0003] For example, plastic films are highly water-resistant and are used as liquid containers, and are widely used in the food industry, including beverages and retort foods, as well as in the fields of daily necessities and toiletries, with a wide variety of products lining the shelves of supermarkets, drugstores, and convenience stores. In addition to liquid containers, plastic films are being used for a variety of other purposes.

[0004] The advantages of packaging bags compared to other containers such as cans and bottles are that they are inexpensive, that detailed material design can be implemented depending on the required quality, and that they are lightweight and space-saving before filling, as well as during distribution and storage. Packaging bags can also be said to be environmentally friendly from the perspective of reducing waste.

[0005] In addition, high-resolution printing on the layer visible from the outside can improve the product's image and display necessary information about the contents, and printing barcodes, for example, can also serve as a source of product distribution and marketing information.

[0006] In particular, when storing contents such as food, depending on the contents, oil or water absorbency, for example, may be required, as well as suitability for use in a microwave oven and the associated vapor permeability, and detailed material design is required to meet each of these required quality requirements.

[0007] For example, Patent Document 1 proposes a packaging bag with water and oil absorption properties. However, because the sealant layer is made of nonwoven fabric, the adhesion of the sealed portion during bag production is poor, which may cause problems with impact resistance and the like.

[0008] In addition, in Patent Document 2, a packaging bag is provided with an evaporation moisture adjustment hole that penetrates from the inside to the outside. However, since the hole is a through hole, there is a risk that foreign objects or insects may get in, and there is also a risk that moisture or oil from the contents may leak out, which may cause problems in practical use. [Prior art documents] [Patent documents]

[0009] [Patent Document 1] Patent No. 3770704 [Patent Document 2] Japanese Unexamined Patent Publication No. 62-275415 Summary of the Invention [Problem to be solved by the invention]

[0010] The present invention has been made in view of the above circumstances, and provides a sealable packaging bag capable of absorbing oil and moisture from the contents and automatically passing the contents through the bag when the contents are heated in a microwave oven. The objective is to provide a packaging bag having a steam mechanism. [Means for solving the problem]

[0011] As a means for solving the above problem, the invention described in claim 1 is: In a packaging bag that can store contents inside and be sealed, The packaging bag is formed by making a bag from the laminate, The laminate is composed of at least a base layer made of a plastic film, a concealing layer, an olefin-based resin intermediate layer, a paper or nonwoven fabric layer, and an innermost olefin-based resin layer, in that order from the outside. The laminate has scratch processing A for steam passage and scratch processing B for water and oil absorption. The scratching process A comprises scratching the base layer made of a plastic film and the concealing layer through both layers, and scratching the paper or nonwoven fabric layer; The scratch processing B is a packaging bag characterized by scratch processing that penetrates both the paper or nonwoven fabric layer and the innermost olefin-based resin layer.

[0012] The invention described in claim 2 is as follows: The packaging bag according to claim 1, wherein the concealing layer is formed by a printing ink.

[0013] The invention described in claim 3 is as follows: The packaging bag according to claim 1 or 2, wherein the olefin-based resin intermediate layer is formed by laminating a layer of molten olefin-based resin using an extruder. Effect of the Invention

[0014] According to the present invention, it is possible to provide a sealable packaging bag that is capable of absorbing oil and moisture from the contents and has an automatic steam passing mechanism when the contents are heated in a microwave oven.

[0015] The laminate constituting the packaging bag is composed of, in order from the outside, at least a base layer made of a plastic film, a concealing layer, an olefin-based resin intermediate layer, a paper or nonwoven fabric layer, and an olefin-based resin layer as an innermost layer, so that the packaging bag has flexibility and is endowed with necessary mechanical strength and a certain degree of heat resistance. Furthermore, the olefin-based resin layer as the innermost layer can be used as a surface that comes into direct contact with the contents and as a sealant layer during bag production.

[0016] The laminate is provided with scratching A for steam passage, that is, scratching that penetrates through the base layer made of a plastic film and the concealing layer, and scratching the paper or nonwoven fabric layer.

[0017] In addition, scratch processing B for water and oil absorption, that is, scratch processing is provided on the paper or nonwoven fabric layer and the innermost olefin resin layer, which penetrates both of them.

[0018] Therefore, by applying the scratching process B, the packaging bag is endowed with the function of absorbing oil and moisture from the contents, and by applying the scratching process A, the packaging bag is endowed with an automatic steaming mechanism when the contents are heated in a microwave oven.

[0019] Furthermore, since the olefin-based resin intermediate layer of this laminate is not subjected to scratching treatment, the produced packaging bag can ensure airtightness before cooking with heat.

[0020] When cooking is performed in a microwave oven, this olefin-based resin intermediate layer breaks and functions as part of the steam passage mechanism. That is, in addition to the through holes of the scratch processing A and scratch processing B, the broken olefin-based resin intermediate layer connects the inside and outside of the packaging bag, making it possible to discharge water vapor generated inside to the outside.

[0021] In particular, according to the invention described in claim 2, when moisture and oil from the contents are absorbed into the laminate, the concealing layer can conceal the effect on the appearance. When the concealing layer is formed by printing ink, the layer can be formed with high productivity by using a known printing method.

[0022] In particular, according to the invention described in claim 3, the olefin-based resin intermediate layer is formed by extruding molten olefin-based resin, which allows for efficient layer formation and enables sealing of the packaging bag. In addition, moisture and oil from the contents absorbed by the paper or nonwoven fabric layer can be blocked by the concealing layer, eliminating any adverse effects on the appearance. [Brief description of the drawings]

[0023] [Figure 1] FIG. 1 is a partial cross-sectional schematic diagram for explaining one embodiment of a laminate constituting a packaging bag according to the present invention, and is also a partial cross-sectional schematic diagram for explaining a laminate constituting an evaluation packaging bag of Example 1. [Diagram 2] FIG. 2 is a partial schematic cross-sectional view illustrating a laminate constituting the evaluation packaging bag of Comparative Example 1. As shown in FIG. [Diagram 3] FIG. 3 is a partial schematic cross-sectional view illustrating a laminate constituting the evaluation packaging bag of Comparative Example 2. As shown in FIG. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0024] The invention will now be described in more detail with reference to the drawings, in which: The invention is not limited to the examples shown, but rather by the claims.

[0025] FIG. 1 is a partial schematic cross-sectional view for explaining one embodiment of a laminate constituting a packaging bag according to the present invention.

[0026] The present invention relates to a packaging bag made of a laminate (10), which is capable of storing contents therein and being sealed.

[0027] In particular, it is capable of storing food as a content, and is capable of absorbing moisture and oil that seeps out from the content. It is also suitable for cooking in a microwave oven, and has the associated automatic steaming properties.

[0028] The packaging bag is formed by making a laminate (10). The laminate (10) is composed of, from the outside, at least a base layer (1) made of a plastic film, a concealing layer (2), an olefin-based resin intermediate layer (3), a paper or nonwoven fabric layer (4), and an innermost olefin-based resin layer (5).

[0029] The plastic film that can constitute the base layer is a film made of a polymer resin composition, and examples of the film that can be used include polyolefin (polyethylene, polypropylene, etc.), polyester (polyethylene terephthalate, polybutylene terephthalate, polyethylene naphthalate, etc.), polyamide (nylon-6, nylon-66, etc.), and polyimide, and are appropriately selected according to the application. In particular, polypropylene and polyethylene terephthalate are The substrate layer (1) made of a plastic film is preferable in terms of film strength and cost.

[0030] Some of these plastic films are manufactured and supplied through a stretching step in the film production process, and are excellent in mechanical strength and precision of film thickness, so stretched plastic films are preferably used.

[0031] The plastic film can also be laminated with other layers via an adhesive layer or the like to form a laminate (10). The layer structure, materials, thickness, etc. of the laminate (10) can be appropriately designed depending on the quality required for the packaging bag.

[0032] The concealing layer (2) is a layer for blocking visible light to make the contents of the packaging bag invisible from the outside. For example, if moisture or oil from the contents seeps into the laminate (10), the affected area may appear discolored with a wet color, resulting in an unsightly appearance. By providing the concealing layer (2), the seepage can be blocked and made invisible from the outside.

[0033] The concealing layer (2) is not particularly limited in terms of its material composition or layer formation, and can be, for example, an opaque printed ink layer. The printed ink layer is formed, for example, in a state in which an opaque pigment is dispersed in a synthetic resin component. Therefore, it is an opaque layer at least in the visible light range.

[0034] When the opaque concealing layer (2) is formed by printing ink using a known printing method, the layer can be formed with higher accuracy and higher productivity. In addition to the printing method, a known coating method can also be used.

[0035] Incidentally, as the concealing layer (2), metal foil such as aluminum or a metal vapor deposition film is also opaque and effective in concealing properties, but is unsuitable when the contents and packaging bag are heated in a microwave oven because high frequency sparks are generated.

[0036] The olefin-based resin intermediate layer (3) is a layer formed using an olefin-based resin, and can be formed, for example, by extruding a molten olefin-based resin. By forming a layer from a molten olefin-based resin using an extruder, it is possible to form the layer with good productivity.

[0037] In addition, at the same time as forming the layer by the extruder, it is also possible to sandwich this layer from the front and back between a base layer (1) made of a plastic film and a concealing layer (2), as well as a paper or nonwoven fabric layer (4) and an innermost olefin-based resin layer (5) as shown in Figure 1, and integrate them to form a laminate.

[0038] This olefin-based resin intermediate layer (3) is located in the middle of the laminate (10) and is not subject to scratch processing A (6) or scratch processing B (7), so it is possible to separate the inside and outside of the packaging bag and make it possible to seal the packaging bag.

[0039] Olefin-based resin is a general term for polypropylene, low-density polyethylene, ethylene-vinyl acetate copolymer, polymethylpentene, ultra-high molecular weight polyethylene, etc., and has the following characteristics.

[0040] -Lightweight with a specific gravity of less than 1. Flexible -Excellent chemical resistance. -Absorbs shock. -Relatively low heat resistance. -It is a general-purpose resin that is easily available and relatively inexpensive. -Easy film formation. -It is a safe substance for the human body.

[0041] Taking advantage of these characteristics, the polyolefin resin is effectively used as the intermediate layer (3) of the laminate constituting the packaging bag according to the present invention.

[0042] The laminate has scratched portions A (6) for steam passage and scratched portions B (7) for water and oil absorption.

[0043] The scratching process A (6) is composed of scratching that penetrates through the base layer (1) made of a plastic film and the concealing layer (2) and scratching the paper or nonwoven fabric layer (4).

[0044] The scratching process A (6) can be used to make the packaging bag equipped with an automatic steaming mechanism when the contents are heated in a microwave oven. When the contents are heated, steam is generated, causing the volume of the packaging bag to expand, and the internal pressure inside the packaging bag rises, causing the olefin resin intermediate layer (3) to break, which, together with the scratching process A (6), becomes a passage for the generated steam, allowing the steam inside to be discharged to the outside, acting as an automatic steaming mechanism.

[0045] There is no particular restriction on the method for forming the scratch processing A(6), but it can be formed, for example, by irradiation with a laser beam.

[0046] The scratching B (7) is provided on the paper or nonwoven fabric layer (4) and the innermost olefin resin layer (5) as a scratching that penetrates both layers.

[0047] The scratch processing B(7) gives the packaging bag the ability to absorb oil and moisture contained in the contents stored inside.

[0048] There is no particular restriction on the method for forming the scratch processing B(7), but it can be formed, for example, by processing using a blade, or by irradiating with a laser beam.

[0049] Excess oil and moisture contained in the contents passes through the scratching process of the innermost olefin-based resin layer (5) of the scratching process B (7), reaches the scratching process B (7) in the paper or nonwoven fabric layer (4), and is absorbed.

[0050] This allows, for example, if the contents are food, to absorb excess oil and moisture contained therein, preventing a deterioration in taste and texture, making it possible to serve the contents in better condition.

[0051] Generally, when oil or moisture is absorbed into the paper or nonwoven fabric layer (4), the absorbed parts turn a wet color, which has an undesirable effect on the appearance. However, in the laminate (10) constituting the packaging bag of the present invention, the olefin-based resin intermediate layer (3) is interposed between the laminate (10) and the concealing layer (2), so that the absorbed oil or moisture is not visible from the outside of the packaging bag.

[0052] The innermost olefin resin layer (5) is also effective as a sealant layer when the laminate is made into a bag.

[0053] The laminate (10) having a sealant layer can be formed into a packaging bag body by stacking two laminates with the sealant layers facing each other and bonding them together, for example by applying heat and pressure to heat seal them.

[0054] As the material for the sealant layer, polyolefin resins, which are thermoplastic resins, are generally used. Specifically, low-density polyethylene resin (LDPE), medium-density polyethylene resin (MDPE), and linear low-density polyethylene resin (LLDPE) can be used.

[0055] In addition, ethylene-based resins such as ethylene-vinyl acetate copolymer (EVA), ethylene-α-olefin copolymer, and ethylene-methacrylic acid resin copolymer, blend resins of polyethylene and polybutene, and polypropylene-based resins such as homopolypropylene resin (PP), propylene-ethylene random copolymer, propylene-ethylene block copolymer, and propylene-α-olefin copolymer can be used.

[0056] The sealant layer can be formed by forming a film of molten resin using an extruder or the like to form a layer on the laminate. Alternatively, a sealant layer can be formed on the surface of the laminate (10) by laminating a material that has already been formed into a film state.

[0057] In this way, according to the present invention, it is possible to provide a sealable packaging bag that is capable of absorbing oil and moisture from the contents and has an automatic steaming mechanism when the contents are heated in a microwave oven. EXAMPLES

[0058] The present invention will be described in more detail below with reference to examples and comparative examples. However, the present invention is not limited to the examples shown here. The present invention is defined by the claims.

[0059] Packaging bags were prepared as evaluation samples and evaluated according to the following items and test methods.

[0060] 1. Product Appearance The packaging bags for evaluation were made by forming the laminate into a 15 cm x 15 cm folded bag, filling it with 100 g of frozen fried rice, sealing it, and leaving it for one hour, and then visually observing the appearance of the packaging bag to evaluate it. The evaluation was carried out by 10 people on a 5-point scale, and the average score was calculated. (Inferior) 1 ←→ 5 (Excellent). Any defects observed were marked as "X" in the evaluation results.

[0061] 2. Product becomes sticky after reheating in the microwave The evaluation packaging bags were made by forming the laminate into a 15 cm x 15 cm shaped bag, filling it with 100 g of frozen fried rice, sealing it, and cooking it in a microwave oven. The package was removed from the microwave oven and the stickiness of the contents and the appearance of the packaging bag surface were visually observed and evaluated. The evaluation was carried out by 10 people on a 5-point scale, and the average score was calculated. (Inferior) 1 ←→ 5 (Excellent). Any defects observed were marked as "X" in the evaluation results.

[0062] 3.Transportation Test The packaging bags for evaluation were made by forming the laminate into a 15 cm x 15 cm shaped gable bag, filling it with 100 g of frozen fried rice, sealing it, and storing 20 of these in a cardboard box. The number of breakages of the evaluation samples and the presence or absence of leakage from the packaging bag were observed and evaluated using a vibration tester. The vibration test conditions were as follows: In a 25°C environment, vertical vibration of 5~50Hz, 0.75G, 120 minutes. Moreover, phenomena that were found to be defective as a result of the observation were marked as "X" in the evaluation results.

[0063] 4. Drop test The packaging bags for evaluation were made by forming the laminate into a 15 cm x 15 cm shaped gable bag, filling it with 100 g of frozen fried rice, sealing it, and storing 20 of these in a cardboard box. A vibration test similar to the transportation test was conducted, and then a drop test was conducted. The conditions for the drop test are as follows: The evaluation sample was dropped 10 times from a height of 80 cm in a 25°C environment, and then the number of breakages in the evaluation sample was observed and evaluated. Moreover, phenomena that were found to be defective as a result of the observation were marked as "X" in the evaluation results.

[0064] <Example 1> FIG. 1 is a partial cross-sectional schematic diagram for explaining one embodiment of a laminate constituting a packaging bag according to the present invention, and is also a partial cross-sectional schematic diagram for explaining a laminate constituting an evaluation packaging bag of Example 1.

[0065] The layer structure of the laminate constituting the evaluation packaging bag is as follows. From the outside of the packaging bag, Polyethylene terephthalate film (thickness 12 μm) / white printing ink layer / extruded polyethylene resin middle layer (thickness 39 μm) / pure white paper layer (30 g / m 2 ) / Innermost polyethylene resin layer (extrusion thickness 30 μm). The scratch processing is as follows: Scratch processing A: A polyethylene terephthalate film (thickness 12 μm) and a white printing ink layer were penetrated. Also, a pure white paper layer (30 g / m 2 ) was penetrated. Scratch processing B: Pure white paper layer (30g / m 2 ) and the innermost polyethylene resin layer (extrusion thickness 30 μm). This structure satisfies the range of regulations regarding the laminate constituting the packaging bag according to the present invention.

[0066] <Comparative Example 1> FIG. 2 is a partial schematic cross-sectional view illustrating a laminate constituting the evaluation packaging bag of Comparative Example 1. As shown in FIG.

[0067] The layer structure of the laminate constituting the evaluation packaging bag is as follows. From the outside of the packaging bag, Polyethylene terephthalate film (thickness 12 μm) / white printing ink layer / extruded polyethylene resin intermediate layer (thickness 39 μm) / nonwoven fabric layer (30 g / m 2 ). The scratch processing is as follows: Scratch processing A: Not provided. Scratch processing B: Not provided. This configuration falls outside the scope of the regulations regarding the laminate constituting the packaging bag according to the present invention.

[0068] <Comparative Example 2> FIG. 3 is a partial schematic cross-sectional view illustrating a laminate constituting the evaluation packaging bag of Comparative Example 2. As shown in FIG.

[0069] The layer structure of the laminate constituting the evaluation packaging bag is as follows. From the outside of the packaging bag, Polyethylene terephthalate film (thickness 12 μm) / white printing ink layer / extruded polyethylene resin middle layer (thickness 39 μm) / innermost polyethylene resin layer (extruded thickness 30 μm). The scratch processing is as follows: Scratch processing C: Polyethylene terephthalate film (thickness 12 μm) and a white printing ink layer and a pure white paper layer (30 g / m 2 ) and the innermost polyethylene resin layer (extrusion thickness 30 μm). In other words, the scratch processing C is provided penetrating all the layers constituting the laminate. Scratch processing B: Pure white paper layer (30g / m 2 ) and the innermost polyethylene resin layer (extrusion thickness 30 μm). This configuration falls outside the scope of the regulations regarding the laminate constituting the packaging bag according to the present invention.

[0070] The evaluation results are shown in Table 1.

[0071] [Table 1]

[0072] As is clear from the results shown in Table 1, in Example 1 according to the present invention, good numerical values ​​and observation results were obtained for all evaluation items, and no phenomena described as defects in Comparative Example 1 or Comparative Example 2 were observed as a result of observation.

[0073] The evaluation results are discussed for each evaluation item. Regarding appearance, Example 1 according to the present invention received a high score of 4.3 points, on a par with Comparative Example 1. This is because the laminate had an olefin-based resin intermediate layer, which was not scratched and functioned as a barrier layer separating the inside and outside of the packaging bag, and no seepage of oil from the frozen fried rice contained therein was observed. On the other hand, Comparative Example 2, which had scratching C penetrating the laminate, resulted in the seepage of oil from the through-holes, which deteriorated the appearance of the packaging bag.

[0074] Regarding stickiness, no significant difference was observed among Example 1, Comparative Example 1, and Comparative Example 2. This is because steam was passed through the contents during cooking, and the contents did not feel sticky. However, in Comparative Example 1, since there was no automatic steam passing mechanism using scratch processing, the center seal part of the seam-attached bag broke as a result, allowing steam to pass through, resulting in poor appearance.

[0075] In the transportation test, no damage was observed in the evaluation samples in Example 1, Comparative Example 1, and Comparative Example 2. However, oil leakage was observed in Comparative Example 2, which resulted in a poor appearance. This is thought to be due to the seepage of oil, as in the appearance evaluation described above.

[0076] Regarding the drop test, damage was observed in the evaluation sample in Comparative Example 2. This was because the tearing of the packaging bag started at scratch processing C, and this is a result of the weak mechanical strength of the laminate in Comparative Example 2. Also, in Comparative Example 1, no damage was observed in the evaluation sample, but the center seal part of the palm-to-palm bonding had a seal failure, which is thought to be due to the seal strength being weak in Comparative Example 2 because the sealant layer is made of nonwoven fabric.

[0077] In this way, according to the present invention, the oil and moisture of the contents in a sealable packaging bag can be prevented. It was verified that it is possible to provide a packaging bag capable of absorbing water and having an automatic steam passing mechanism when the contents are heated in a microwave oven. [Explanation of symbols]

[0078] 1. Base layer made of plastic film 2. Hidden layer 3. Olefin resin intermediate layer 4...Paper or nonwoven fabric layer 5. Innermost layer: olefin-based resin layer 6...Scratch processing A 7...Scratch processing B 8. Nonwoven fabric 9...Scratch processing C 10...Laminate

Claims

1. In a packaging bag that can store contents inside and be sealed, The packaging bag is formed by making a bag from the laminate, The laminate is composed of at least a base layer made of a plastic film, a concealing layer, an olefin-based resin intermediate layer, a paper or nonwoven fabric layer, and an innermost olefin-based resin layer, in that order from the outside. The laminate is provided with scratch processing A for steam passage and scratch processing B for water and oil absorption, The scratching process A includes scratching the base layer made of a plastic film and the concealing layer through both layers, and scratching the paper or nonwoven fabric layer. The packaging bag is characterized in that the scratching process B is performed by scratching the paper or nonwoven fabric layer and the innermost olefin-based resin layer, penetrating both layers.

2. 2. The packaging bag according to claim 1, wherein the concealing layer is formed by printing ink.

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