Film for food packaging and food package using same

Abstract

The present invention relates to a food packaging film and a food package using same, the food packaging film comprising an expanded film comprising: a core layer containing closed cells; and a skin layer containing a polyethylene-based component.

Description

Food packaging film and food packaging body using the same

[0001] The present invention relates to a food packaging film that is environmentally friendly and has excellent distribution stability by reducing the amount of plastic used, and a food packaging body using the same.

[0002] As the use of packaging materials for food increases due to changes in various household types and lifestyles, interest in eco-friendly food packaging materials that can reduce the use of plastics, which are mainly used in packaging, is growing.

[0003] For example, food packaging materials can be manufactured using a non-foaming method that uses heat-stable polypropylene, or a foaming method that mixes polystyrene with a foaming agent or foaming gas and extrudes it. Non-foaming packaging materials have a low rate of shape change and detectable harmful substances at high temperatures, but are less price competitive than foaming packaging materials of the same thickness. In addition, foaming packaging materials can maintain a relatively thick thickness with the same amount of plastic used, which is advantageous in terms of weight reduction and price competitiveness, but when raw materials such as polystyrene are used, there is the problem of harmful substances being detected at high temperatures. In addition, compared to non-foaming packaging materials, the mechanical properties such as strength are lower, so durability is not high, and the container can be broken or damaged due to external impact, etc., so there is a problem of low distribution stability.

[0004] In addition, foam packaging materials using expanded synthetic resins such as polystyrene paper (PSP), expanded polystyrene (EPS), expanded polyethylene (EPE), and expanded polypropylene (EPP) are recycled through an ingot recycling process that melts the separated raw materials, removes air, and reduces their volume. However, if the material is not white or has labels directly printed on it, the color of the ingot may discolor, reducing its value and quality as a recycled raw material. Furthermore, packaging materials composed of composite materials or using adhesives may be difficult to separate from other materials, making recycling impossible. Therefore, research is ongoing into food packaging materials that can reduce the amount of plastic raw materials used while also providing excellent distribution stability.

[0005] For example, Korean Patent Publication No. 10-0892760 discloses an absorbent tray having an open-cell structure and a manufacturing method thereof by foaming and molding a mixture containing polystyrene, a nucleating agent, and an antistatic agent. However, trays using such polystyrene have low recyclability, a low heat-resistant temperature, so there is a risk of deformation when cooking at high temperatures, and environmental hormones may be released at high temperatures, making them unsuitable as packaging materials for frozen processed foods that require hot water or microwave cooking, and so are not easily applied to various fields.

[0006] [Prior Art Literature]

[0007] [Patent Document]

[0008] (Patent Document 1) Korean Patent No. 10-0892760

[0009] Accordingly, the present invention aims to provide a film for food packaging that is environmentally friendly and has excellent distribution stability by reducing the amount of plastic raw materials used, and a food packaging body using the film.

[0010] A food packaging film according to one embodiment of the present invention comprises a foamed film comprising a core layer including closed cells; and a skin layer including a polyethylene component.

[0011] According to one embodiment of the present invention, the core layer may include the closed cell in an amount of 40% to 95% by volume based on the total volume of the core layer.

[0012] According to one embodiment of the present invention, the thickness of the core layer may be 20% or more of the total thickness of the foam film.

[0013] According to one embodiment of the present invention, the core layer may have a melting index (MI) of 0.3 to 1.2.

[0014] According to one embodiment of the present invention, the core layer has a density of 0.7 g / cm 3 0.97 g / cm 3 It could be.

[0015] According to one embodiment of the present invention, the core layer may include at least one selected from the group consisting of polyethylene (PE), ethylene vinyl acetate (EVA), linear low-density polyethylene (LLDPE), low-density polyethylene (LDPE), medium-density polyethylene (MDPE), high-density polyethylene (HDPE), polyolefin elastomer (POE), and polyolefin plastomer (POP).

[0016] According to one embodiment of the present invention, the skin layer may be an inner layer that comes into contact with food.

[0017] According to one embodiment of the present invention, the skin layer may include at least one selected from the group consisting of polyethylene (PE), ethylene vinyl acetate (EVA), linear low-density polyethylene (LLDPE), low-density polyethylene (LDPE), medium-density polyethylene (MDPE), high-density polyethylene (HDPE), polyolefin elastomer (POE), and polyolefin plastomer (POP).

[0018] According to one embodiment of the present invention, the thickness of the core layer may be 20 μm to 100 μm.

[0019] According to one embodiment of the present invention, the thickness of the skin layer may be 10 μm to 100 μm.

[0020] According to one embodiment of the present invention, the total thickness of the foam film may be 30 μm to 250 μm.

[0021] According to one embodiment of the present invention, the skin layer includes a first skin layer and a second skin layer, the first skin layer is disposed on one surface of the core layer, the second skin layer is disposed on the other surface of the core layer, and the first skin layer can come into contact with food.

[0022] According to one embodiment of the present invention, the thickness ratio of the second skin layer: the core layer: the first skin layer may be 1:0.5 to 5:1.

[0023] According to one embodiment of the present invention, the food packaging film may include a substrate layer.

[0024] According to one embodiment of the present invention, the substrate layer may include at least one selected from the group consisting of nylon (NY), polyethylene (PE), ethylene vinyl acetate (EVA), linear low-density polyethylene (LLDPE), low-density polyethylene (LDPE), medium-density polyethylene (MDPE), high-density polyethylene (HDPE), polyethylene terephthalate (PET), and polypropylene (PP).

[0025] According to one embodiment of the present invention, the skin layer may include a first skin layer and a second skin layer, and the food packaging film may be formed by sequentially laminating the base layer, the second skin layer, the core layer, and the first skin layer.

[0026] According to one embodiment of the present invention, the weight ratio of the foam film and the substrate layer may be 1:0.1 to 0.85.

[0027] According to one embodiment of the present invention, an adhesive layer may be included between the substrate layer and the foam film.

[0028] According to one embodiment of the present invention, the food packaging film may include a barrier layer.

[0029] According to one embodiment of the present invention, the barrier layer may include at least one selected from the group consisting of aluminum, ethylene-vinyl alcohol (EVOH), polyvinylidene chloride (PVDC), and polyvinyl chloride (PVC).

[0030] According to one embodiment of the present invention, the food packaging film may include a printing layer.

[0031] According to one embodiment of the present invention, the printing layer may include at least one selected from the group consisting of polyethylene terephthalate (PET), nylon (NY), and stretched polypropylene (OPP).

[0032] According to another embodiment of the present invention, a food packaging body comprises: a food; and a food packaging film for sealing the food, wherein the food packaging film comprises a foam film comprising a core layer including closed cells and a skin layer including a polyethylene component.

[0033] According to another embodiment of the present invention, the food packaging body may have a puncture strength of 0.5 kgf or more.

[0034] According to another embodiment of the present invention, the dart impact strength may be 15 kgf or more.

[0035] A food packaging film according to one embodiment of the present invention comprises a foam film comprising a core layer including closed cells and a skin layer including a polyethylene component, thereby being environmentally friendly and having excellent distribution stability.

[0036] Specifically, foam molding is a molding method that generates bubbles by adding a foaming agent to a plastic raw material, and polystyrene is mainly used. Unlike open-cell packaging materials such as polystyrene paper (PSP) or expanded polystyrene (EPS), expanded polyethylene (EPE), expanded polypropylene (EPP), etc., to which conventional foaming technology is applied, a food packaging film according to an embodiment of the present invention includes a core layer in which closed-cell foam pores are formed, thereby reducing the amount of plastic used and thus being environmentally friendly.

[0037] More specifically, the closed cells formed in the core layer can increase the physical thickness of the core layer during the extrusion process, thereby enabling a film of the same thickness to be obtained using less plastic raw materials compared to a conventional film of the same thickness. As a specific example, a food packaging film according to one embodiment of the present invention may have a plastic usage amount reduced by at least 10% compared to a conventional food packaging film.

[0038] In addition, the food packaging film includes a skin layer containing a polyethylene component on at least one side of the core layer, and by arranging the skin layer as an inner layer in contact with food, it is possible to minimize the deterioration of mechanical properties such as impact resistance, pinhole resistance, and tear resistance while using a smaller amount of plastic than in the past, thereby securing mechanical properties equivalent to those in the past, and having excellent distribution stability.

[0039] Therefore, when manufacturing a food packaging body using the above food packaging film, it is possible to effectively prevent the filled food from being damaged during the distribution process, and the appearance of the food packaging body is also good, so it has excellent distribution stability.

[0040] Figure 1 illustrates a laminated structure of a foam film according to one embodiment of the present invention.

[0041] Figure 2 illustrates a laminated structure of a foam film according to another embodiment of the present invention.

[0042] Figure 3 illustrates a laminated structure of a food packaging film according to one embodiment of the present invention.

[0043] Figure 4 illustrates a laminated structure of a food packaging film according to another embodiment of the present invention.

[0044] Hereinafter, the present invention will be described in detail. The present invention is not limited to the contents disclosed below and may be modified in various forms without changing the gist of the invention.

[0045] In this specification, when a part is said to "include" a certain component, this does not mean that it excludes other components, but rather that it may include other components, unless otherwise specifically stated.

[0046] All numbers and expressions indicating the amounts of components, reaction conditions, etc. described in this specification should be understood to be modified by the term “about” in all cases unless otherwise specified.

[0047] When it is described in this specification that one component is formed on or under another component, it includes both cases where one component is formed directly on or under the other component, or indirectly through the interposition of another component.

[0048] In this specification, the terms "first," "second," "primary," and "secondary" are used to describe various components, and the components are not limited by the terms. The terms are used solely to distinguish one component from another.

[0049]

[0050] Food packaging film

[0051] A food packaging film according to one embodiment of the present invention comprises a foamed film comprising a core layer including closed cells; and a skin layer including a polyethylene component.

[0052] A food packaging film according to one embodiment of the present invention may have a plastic usage amount reduced by 10% or more compared to a conventional food packaging film. More specifically, the food packaging film includes a foam film including the core layer and the skin layer, thereby having a sufficient thickness with a plastic usage amount reduced by 11% or more, 12% or more, 15% or more, 20% or more, 25% or more, or 28% or more compared to a conventional film of the same thickness, and having mechanical properties such as impact resistance, pinhole resistance, and tear resistance that can ensure distribution stability required during the distribution process.

[0053] A food packaging film according to one embodiment of the present invention includes a foam film.

[0054] Figure 1 illustrates the laminated structure of a foam film according to one embodiment of the present invention. Referring to Figure 1, a foam film (100) according to one embodiment of the present invention has a laminated structure of a skin layer (120) and a core layer (110). In this case, the skin layer may be an inner layer that comes into contact with food.

[0055] More specifically, the food packaging film comprises a core layer and a skin layer, and the skin layer is arranged as an inner layer in contact with the food, thereby effectively protecting the food from internal and external impacts, thereby ensuring excellent distribution stability. For example, in the case of frozen foods with sharp shapes such as dumplings, damage mainly occurs due to an outward impact of the product when dropped or vibrated during distribution. In this case, the food packaging film according to one embodiment of the present invention has excellent distribution stability because the foam film can effectively perform a buffering function.

[0056] According to one embodiment of the present invention, the foam film includes a core layer.

[0057] The core layer may include a plurality of cells. For example, the core layer may be formed by a physical foaming method or a chemical foaming method. As a specific example, the core layer may be formed by extrusion using a physical foaming method utilizing a supercritical fluid, and a film may be formed and closed cells may be formed by injecting an ultra-high-pressure supercritical fluid and a nucleating agent and cooling the film by decreasing the temperature and pressure during the blow molding step, but the present invention is not limited thereto.

[0058] The core layer may contain the closed cells in an amount of 40% by volume to 95% by volume based on the total volume of the core layer. For example, the core layer may contain the closed cells in an amount of 45% by volume to 90% by volume, 50% by volume to 90% by volume, or 50% by volume to 85% by volume based on the total volume of the core layer. Since the volume of the closed cells in the core layer satisfies the above range, compared to a conventional food packaging film of the same thickness, distribution stability required during the distribution process can be secured without deterioration of mechanical properties such as impact resistance, pinhole resistance, and tear resistance with a plastic usage amount that is 10% or less.

[0059] The thickness of the core layer may be 20% or more of the total thickness of the foam film. For example, the thickness of the core layer may be 25% or more, 35% or more, 40% or more, 50% or more, 90% or less, 80% or less, or 70% or less of the total thickness of the foam film. By satisfying the thickness of the core layer within the above range, it may be advantageous to secure mechanical properties such as impact resistance, pinhole resistance, and tear resistance.

[0060] For example, the thickness of the core layer may be from 20 μm to 100 μm. For example, the thickness of the core layer may be 22 μm or more, 25 μm or more, 27 μm or more, or 30 μm or more, and 100 μm or less, 90 μm or less, 80 μm or less, 70 μm or less, or 50 μm or less.

[0061] Additionally, the core layer may have a melting index (MI) of 0.3 to 1.2. For example, the melting index (MI) of the core layer may be 0.35 to 1.2, 0.4 to 1.0, or 0.5 to 0.8.

[0062] The above core layer has a density of 0.7 g / cm 3 0.97 g / cm 3 may be. For example, the density of the core layer may be 0.75 g / cm 3 0.97 g / cm 3 , 0.8 g / cm 3 0.96 g / cm 3 , 0.9 g / cm 3 0.95 g / cm 3 or 0.92 g / cm 3 0.94 g / cm 3 It could be.

[0063] Since the melting index and density of the core layer each satisfy the above ranges, distribution stability can be secured without deterioration of mechanical properties such as impact resistance, pinhole resistance, and tear resistance.

[0064] The core layer may include at least one selected from the group consisting of polyethylene (PE), ethylene vinyl acetate (EVA), linear low-density polyethylene (LLDPE), low-density polyethylene (LDPE), medium-density polyethylene (MDPE), high-density polyethylene (HDPE), polyolefin elastomer (POE), and polyolefin plastomer (POP).

[0065] According to one embodiment of the present invention, the foam film includes a skin layer.

[0066] The above skin layer may include at least one selected from the group consisting of polyethylene (PE), ethylene vinyl acetate (EVA), linear low-density polyethylene (LLDPE), low-density polyethylene (LDPE), medium-density polyethylene (MDPE), high-density polyethylene (HDPE), polyolefin elastomer (POE), and polyolefin plastomer (POP).

[0067] According to one embodiment of the present specification, the skin layer may include a first skin layer and a second skin layer, the first skin layer may be disposed on one surface of the core layer, the second skin layer may be disposed on the other surface of the core layer, and the first skin layer may be structured to be in contact with food.

[0068] According to another embodiment of the present specification, the core layer may include a first skin layer and a second skin layer on each side, and the foam film may be formed by sequentially laminating the first skin layer, the core layer, and the second skin layer, and the first skin layer may be an inner layer that comes into contact with food.

[0069] Fig. 2 illustrates a laminated structure of a foam film according to another embodiment of the present invention. Referring to Fig. 2, a foam film (100) according to one embodiment of the present invention has a structure in which a first skin layer (121) is disposed on one surface of a core layer (110), and a second skin layer (122) is disposed on the other surface of the core layer (110). The first skin layer (121), the core layer (110), and the second skin layer (122) may be laminated in that order. In this case, the first skin layer may be an inner layer that comes into contact with food.

[0070] As described above, the foam film having a three-layer structure can more effectively protect the food from internal and external impacts by arranging the core layer between the first skin layer, which is the inner layer in contact with the food, and the second skin layer, which is in contact with the outside, thereby ensuring excellent distribution stability. For example, in the case of frozen foods with sharp shapes such as dumplings, damage mainly occurs due to an impact directed outward when the product is dropped or vibrated during distribution. In this case, the food packaging film according to one embodiment of the present invention can more effectively prevent damage to the first skin layer in contact with the food, as the second skin layer of the foam film primarily absorbs the impact, and the core layer, which is the middle layer, performs a cushioning role by absorbing the impact.

[0071] The components of the first skin layer and the second skin layer may be the same or different. In addition, the thicknesses of the first skin layer and the second skin layer may be the same or different. The description of the first skin layer and the second skin layer is the same as that described above for the skin layer.

[0072] Additionally, the thickness of the skin layer may be 10 μm to 100 μm. For example, the thickness of the skin layer may be 10 μm to 85 μm, 10 μm to 80 μm, 12 μm to 60 μm, 15 μm to 50 μm, 15 μm to 45 μm, or 15 μm to 35 μm. The thickness of the skin layer may be the thickness of each of the first skin layer and the second skin layer, or may be the total thickness of the first skin layer and the second skin layer. As a specific example, the foam film may include only a first skin layer, or may include first and second skin layers, wherein the thicknesses of the first and second skin layers may be 10 μm to 85 μm, 10 μm to 80 μm, 12 μm to 60 μm, 15 μm to 50 μm, 15 μm to 45 μm, or 15 μm to 35 μm, respectively.

[0073] In addition, when the foam film includes the second skin layer, the core layer, and the first skin layer, the thickness ratio of the second skin layer: the core layer: the first skin layer may be 1:0.5 to 5:1. For example, the thickness ratio of the second skin layer: the core layer: the first skin layer may be 1:0.5 to 3.5:1 or 1:0.5 to 3:1. By satisfying the thickness ratio of the first skin layer, the core layer, and the first skin layer within the above range, compared to a conventional food packaging film of the same thickness, distribution stability required during the distribution process can be secured without deterioration of mechanical properties such as impact resistance, pinhole resistance, and tear resistance with a plastic usage amount that is 10% or less.

[0074] The total thickness of the foam film may be 30 μm to 250 μm. For example, the total thickness of the foam film may be 40 μm to 220 μm, 45 μm to 200 μm, 50 μm to 150 μm, 50 μm to 100 μm, or 55 μm to 80 μm.

[0075] Additionally, the foam film may be formed by coextrusion, but is not limited thereto.

[0076] According to another embodiment of the present invention, the food packaging film may include a substrate layer.

[0077] Additionally, an adhesive layer may be included between the substrate layer and the foam film. More specifically, an adhesive layer may be included between the second skin layer of the foam film and the substrate layer.

[0078] According to one embodiment of the present invention, the skin layer includes a first skin layer and a second skin layer, and the food packaging film may be laminated in sequence with the first skin layer, the core layer, the second skin layer, and the substrate layer. In this case, the first skin layer may be an inner layer that comes into contact with food.

[0079] Fig. 3 illustrates a laminated structure of a food packaging film according to one embodiment of the present invention. Referring to Fig. 3, a food packaging film according to one embodiment of the present invention may have a structure in which a foam film (100), an adhesive layer (200), and a substrate layer (300) are laminated in that order. More specifically, a first skin layer (121), a core layer (110), a second skin layer (122), an adhesive layer (200), and a substrate layer (300) may be laminated in that order. In this case, the first skin layer may be an inner layer that comes into contact with food.

[0080] The above-mentioned substrate layer may include at least one selected from the group consisting of nylon (NY), polyethylene (PE), ethylene vinyl acetate (EVA), linear low-density polyethylene (LLDPE), low-density polyethylene (LDPE), medium-density polyethylene (MDPE), high-density polyethylene (HDPE), polyethylene terephthalate (PET), and polypropylene (PP).

[0081] The thickness of the substrate layer may be 10 μm to 30 μm. For example, the thickness of the substrate layer may be 15 μm to 30 μm, 15 μm to 25 μm, or 10 μm to 20 μm.

[0082] In addition, the thickness of the substrate layer may be 5% to 30% based on the total thickness of the food packaging film. Specifically, the thickness of the substrate layer may be 5% or more, 10% or more, 12% or more, or 15% or more, and 30% or less, 25% or less, or 20% or less based on the total thickness of the food packaging film, but is not limited thereto.

[0083] A food packaging film according to one embodiment of the present invention may reduce the amount of plastic used by 10% or more compared to a conventional food packaging film by including the foam film. Accordingly, the food packaging film according to one embodiment of the present invention may have a lower weight of the substrate layer relative to the foam film than a conventional food packaging film. For example, the weight ratio of the foam film and the substrate layer may be 1:0.1 to 0.85, 1:0.1 to 0.6, 1:0.1 to 0.55, or 1:0.1 to 0.5.

[0084] The adhesive layer may be formed by melting a plastic resin, but is not limited thereto. As a specific example, the adhesive layer may be formed using at least one resin selected from the group consisting of polyethylene, a urethane-based elastomer, a styrene-based elastomer, maleic anhydride-modified polyethylene, maleic anhydride-modified polypropylene, and ethylene vinyl acetate (EVA). In addition, the adhesive layer may be formed using an adhesive capable of compositely bonding identical or different films. As a specific example, the adhesive layer may be formed using an adhesive such as a polyurethane-based or acrylic-based adhesive, but is not limited thereto.

[0085] Additionally, the thickness of the adhesive layer may be 1 μm to 30 μm. For example, the thickness of the substrate layer may be 2 μm to 25 μm, 5 μm to 22 μm, 10 μm to 20 μm, or 15 μm to 30 μm.

[0086] A food packaging film according to another embodiment of the present invention may include a barrier layer. In addition, a food packaging film according to another embodiment of the present invention may include a printed layer.

[0087] As a specific example, the food packaging film may include the foam film, the barrier layer, and the printing layer, and the foam film, the barrier layer, and the printing layer may be laminated in that order.

[0088] Additionally, a first adhesive layer and a second adhesive layer may be included between the foam film and the barrier layer, and between the barrier layer and the printed layer, respectively.

[0089] The components of the first adhesive layer and the second adhesive layer may be the same or different. In addition, the thicknesses of the first adhesive layer and the second adhesive layer may be the same or different. The description of the first adhesive layer and the second adhesive layer is the same as that described above for the adhesive layer.

[0090] Fig. 4 illustrates a laminated structure of a food packaging film according to another embodiment of the present invention. Referring to Fig. 4, a food packaging film according to an embodiment of the present invention may have a structure in which a foam film (100), a first adhesive layer (210), a barrier layer (400), a second adhesive layer (220), and a print layer (500) are laminated in that order. More specifically, a first skin layer (121), a core layer (110), a second skin layer (122), a first adhesive layer (210), a barrier layer (400), a second adhesive layer (220), and a print layer (500) may be laminated in that order. In this case, the first skin layer may be an inner layer that comes into contact with food.

[0091] The above barrier layer may include at least one selected from the group consisting of aluminum, ethylene-vinyl alcohol (EVOH), polyvinylidene chloride (PVDC), and polyvinyl chloride (PVC).

[0092] Additionally, the thickness of the barrier layer may be 5 nm to 50 μm, 10 nm to 40 μm, 100 nm to 35 μm, 500 nm to 20 μm, 1 μm to 15 μm, or 3 μm to 10 μm.

[0093] The above printing layer may include at least one selected from the group consisting of polyethylene terephthalate (PET), nylon (NY), and stretched polypropylene (OPP).

[0094] Additionally, the thickness of the printed layer may be 5 ㎛ to 40 ㎛, 5 ㎛ to 30 ㎛, 5 ㎛ to 15 ㎛, or 10 ㎛ to 15 ㎛.

[0095] The total thickness of the above food packaging film may be 45 µm to 300 µm, 50 µm to 250 µm, 50 µm to 200 µm, 60 µm to 180 µm, or 70 µm to 150 µm.

[0096] In addition, the food packaging film may be manufactured through a bonding method such as dry lamination, extrusion lamination, non-solvent lamination, wet lamination, etc., but is not limited thereto. As a specific example, the food packaging film may be manufactured by laminating a foam film manufactured through coextrusion with a substrate layer, a barrier layer, and / or a printing layer. At this time, the lamination may be performed using at least one selected from the group consisting of polyethylene, a urethane-based elastomer, a styrene-based elastomer, maleic anhydride-modified polyethylene, maleic anhydride-modified polypropylene, and ethylene vinyl acetate (EVA), but is not limited thereto.

[0097]

[0098] food packaging

[0099] According to another embodiment of the present invention, a food packaging body comprises: a food; and a food packaging film for sealing the food, wherein the food packaging film comprises a foam film comprising a core layer including closed cells and a skin layer including a polyethylene component.

[0100] The food packaging body may have a puncture strength of 0.5 kgf or more. For example, the puncture strength of the food packaging body is measured as the maximum strength when a 0.8 mm pin is pierced at a speed of 50 mm / min in the inner direction in contact with the food or in the outer direction in contact with the outside and broken, and may be 0.5 kgf or more, 0.6 kgf or more, 0.65 kgf or more, or 0.8 kgf or more. More specifically, the puncture strength in the inner direction in contact with the food in the food packaging body may be 0.6 kgf or more, 0.65 kgf or more, 0.7 kgf or more, or 0.8 kgf or more, and the puncture strength in the outer direction in contact with the outside in the food packaging body may be 0.5 kgf or more, 0.55 kgf or more, 0.7 kgf or more, or 0.8 kgf or more.

[0101] The food packaging may have a dart impact strength of 15 kgf or more. For example, the dart impact strength of the food packaging may be measured under the conditions of a dart weight of 1.605 kg and a drop height of 400 mm according to ISO 7765-2, and may be 15.5 kgf or more, 16 kgf or more, 16.2 kgf or more, 17 kgf or more, 19 kgf or more, 20 kgf or more, or 21 kgf or more. More specifically, the dart impact strength in the inward direction in contact with the food in the food packaging body may be 15 kgf or more, 15.5 kgf or more, 16.5 kgf or more, 18 kgf or more, or 18.5 kgf or more, and the dart impact strength in the outward direction in contact with the outside in the food packaging body may be 15.6 kgf or more, 16 kgf or more, 17 kgf or more, 19 kgf or more, or 20 kgf or more.

[0102] The above contents are explained in more detail with the following examples. However, the following examples are only intended to illustrate the present invention, and the scope of the examples is not limited to these examples.

[0103]

[0104] [Example]

[0105] Manufacturing of food packaging films

[0106] Example 1-1

[0107] Foam film (three-layer structure of second skin layer / core layer / first skin layer, total thickness: 60 ㎛, core layer: PE (including closed cell, thickness: 30 ㎛, melt index (MI): 0.8, density: 0.910 g / cm) 3 0.925 g / cm 3 ), the first and second skin layers: PE (thickness: 15 ㎛ each)) and the substrate layer (nylon film (NY), thickness: 15 ㎛) were laminated using an extrusion lamination method to manufacture a food packaging film with a total thickness of 95 ㎛.

[0108] At this time, the lamination was performed using a polyethylene resin, so that an adhesive layer (thickness: 20 ㎛) was formed between the foam film and the substrate layer. That is, the food packaging film has a laminated structure of substrate layer (NY) / adhesive layer / foam film (second skin layer / core layer / first skin layer).

[0109]

[0110] Comparative Example 1-1

[0111] A food packaging film (laminated structure of base layer (NY) / adhesive layer / LLDPE, total thickness: 95 μm) was manufactured in the same manner as in Example 1-1, except that linear low-density polyethylene (LLDPE, thickness: 60 μm) was used instead of the foam film.

[0112]

[0113] Experimental Example 1: Weight of each layer

[0114] The weights of each layer of the food packaging films of Example 1-1 and Comparative Example 1-1, manufactured to the same thickness (95 ㎛) through lamination, were compared. At this time, the total weight of the food packaging film of Example 1-1 was 8.13 g, and the total weight of the food packaging film of Comparative Example 1-1 was 9.74 g.

[0115]

[0116] Example 1-1 Weight (weight %) Comparative Example 1-1 Weight (weight %) Foam film 53.1 LLDPE 60.9 Adhesive layer 24.3 Adhesive layer 20.2 NY 22.6 NY 18.9

[0117]

[0118] As described in Table 1 above, the food packaging film of Example 1-1, which includes a foam film comprising a core layer and a skin layer of the present invention, had a weight reduction of about 16.5% compared to Comparative Example 1-1, which is a conventional food packaging film manufactured to the same thickness. Specifically, when the weight of the foam film of Example 1-1 is compared to the weight of the same area of ​​the LLDPE of Comparative Example 1-1, the weight is about 27.2% less, and thus the amount of raw materials used in manufacturing the food packaging film is reduced.

[0119]

[0120] Experimental Example 2: Stab strength and dart impact strength

[0121] For the food packaging films of Example 1-1 and Comparative Example 1-1, mechanical properties were evaluated by measuring the puncture strength and dart impact strength.

[0122] Specifically, for food packaging films, the maximum strength when a 0.8 mm pin is inserted into the inner or outer direction of the film at a speed of 50 mm / min and breaks was measured as the puncture strength, and the dart impact strength was measured under the conditions of a dart weight of 1.605 kg and a dropping height of 400 mm according to ISO 7765-2, and the results are shown in Table 2 below. At this time, the outer side of Example 1-1 and Comparative Example 1-1 is NY, and the inner side is the side in contact with food, and the inner side of Example 1-1 is a foam film, and the inner side of Comparative Example 1-1 is LLDPE.

[0123]

[0124] Manufacturing of food packaging

[0125] Example 2-1 and Comparative Example 2-1

[0126] A food packaging body was manufactured by filling the inside of each of the food packaging films of Example 1-1 and Comparative Example 1-1 with frozen fried meat and sealing the film.

[0127]

[0128] Experimental Example 3: Distribution Stability

[0129] After placing the food packaging bodies of Example 2-1 and Comparative Example 2-1 in boxes, an evaluation was performed at Assurance level 1 according to ASTM D 4169-16, and the results are shown in Table 2 below. Specifically, the first drop, first vibration, second vibration, and second drop were performed under the following conditions, and the breakage rate such as pinholes or tears was calculated to evaluate distribution stability.

[0130] - 1st drop method and number of times: 2 corner drops, 2 apex drops, 2 surface drops (1 top, 1 bottom) a total of 6 drops from 610 mm

[0131] - 1st box compression load and time: Example 2-1 163.2 kgf, 3 sec / Comparative Example 2-1 156 kgf, 3 sec

[0132] - 1st vibration: Truck low level 40 min -> Truck Medium level 15 min -> Truck High level 5 min

[0133] - Secondary vibration: Same as first vibration

[0134] - Secondary box compression load and time: 479.2 kgf, 2 sec for both Example 2-1 and Comparative Example 2-1

[0135] - Secondary drop method and number of times: Dropped once from the top, twice from the corners, and twice from the side with a drop height of 610 mm, then dropped on the floor with a drop height of 1,220 mm

[0136]

[0137] Film for packaging of food compartments, food compartments, packaging body, puncture strength (kgf), distribution stability evaluation (breakage rate, %), outer side, inner side, example 1-10.8, example 2-111.1, comparative example 1-10.8, 0.8, comparative example 2-127.8

[0138]

[0139] As shown in Table 2 above, the food packaging film of Example 1-1 exhibited mechanical properties equivalent to those of Comparative Example 1-1, a conventional food packaging film manufactured to the same thickness, despite the reduced amount of raw materials used.

[0140] In addition, as a result of performing a distribution stability test on the food packaging bodies of Example 2-1 and Comparative Example 2-1 manufactured using the food packaging films of Example 1-1 and Comparative Example 1-1, the food packaging film of Example 2-1 had excellent distribution stability despite the fact that the amount of raw materials used was reduced compared to the conventional food packaging film, Comparative Example 2-1. At this time, the breakage rate was calculated as the ratio of food packaging bodies with pinholes or tears among 36 food packaging bodies placed in a box, and in the case of Example 2-1, 4 were broken (11.1%), and in the case of Comparative Example 2-1, 10 were broken (27.8%).

[0141]

[0142] Manufacturing of food packaging films

[0143] Example 1-2

[0144] Foam film (three-layer structure of second skin layer / core layer / first skin layer, total thickness: 70 ㎛, core layer: PE (including closed cell, thickness: 35 ㎛, melt index (MI): 0.8, density: 0.910 g / cm) 3 0.925 g / cm 3 ), the first and second skin layers: PE (thickness: 17.5 ㎛ each)), barrier layer (aluminum foil (AL), thickness: 7 ㎛) and printing layer (polyethylene terephthalate film (PET), thickness: 12 ㎛) were sequentially arranged and laminated using an extrusion lamination method to manufacture a food packaging film with a total thickness of 129 ㎛.

[0145] At this time, the lamination was performed using a polyethylene resin, so that a first adhesive layer (thickness: 20 μm) was formed between the foam film and the barrier layer (AL), and a second adhesive layer (thickness: 20 μm) was formed between the barrier layer (AL) and the print layer (PET). That is, the food packaging film has a laminated structure of print layer (PET) / second adhesive layer / barrier layer (AL) / first adhesive layer / foam film (second skin layer / core layer / first skin layer).

[0146]

[0147] Comparative Example 1-2

[0148] A food packaging film (laminated structure of printing layer (PET) / second adhesive layer / AL / first adhesive layer / LLDPE, total thickness: 129 μm) was manufactured in the same manner as in Example 1-2, except that linear low-density polyethylene (LLDPE, thickness: 70 μm) was used instead of the foam film.

[0149]

[0150] Experimental Example 4: Weight of each layer

[0151] The weights of each layer of the food packaging films of Example 1-2 and Comparative Example 1-2, manufactured to the same thickness through lamination, were compared. At this time, the total weight of the food packaging film of Example 1-2 was 17.03 g, and the total weight of the food packaging film of Comparative Example 1-2 was 19.51 g.

[0152]

[0153] Example 1-2 Weight (weight %) Comparative Example 1-2 Weight (weight %) Foam film 39.3 LLDPE 47.0 First adhesive layer 15.4 First adhesive layer 13.4 AL 15.8 AL 13.9 Second adhesive layer 15.4 Second adhesive layer 13.4 PET 14.1 PET 12.3

[0154]

[0155] The food packaging film of Example 1-2, which includes the foam film manufactured as described in Table 3 above, had a weight reduction of approximately 12.7% compared to Comparative Example 1-2, a conventional food packaging film manufactured to the same thickness. Specifically, when the weight of the foam film of Example 1-2 is compared to the weight of the same area of ​​the LLDPE of Comparative Example 1-2, the weight is approximately 27% less, and thus the amount of raw materials used in manufacturing the food packaging film is reduced.

[0156]

[0157] Experimental Example 5: Stab strength and dart impact strength

[0158] For the food packaging films of Example 1-2 and Comparative Example 1-2, mechanical properties were evaluated by measuring the puncture strength and dart impact strength.

[0159] Specifically, for food packaging films, the maximum strength when a 0.8 mm pin is inserted into the film at a speed of 50 mm / min in the inner or outer direction and breaks was measured as the puncture strength, and the dart impact strength was measured under the conditions of a dart weight of 1.605 kg and a drop height of 80 mm according to ISO 7765-2, and the results are shown in Table 4 below. At this time, the outer side of Example 1-2 is PET, the inner side is the side in contact with food, the inner side of Example 1-2 is a foam film, and the inner side of Comparative Example 1-2 is LLDPE.

[0160]

[0161] Manufacturing of food packaging

[0162] Example 2-2 and Comparative Example 2-2

[0163] Using the food packaging films of Example 1-2 and Comparative Example 1-2, 2 kg of powdered product was filled inside each film and sealed to manufacture a food packaging body.

[0164]

[0165] Experimental Example 6: Distribution Stability

[0166] After placing the food packaging bodies of Example 2-2 and Comparative Example 2-2 in a box, an evaluation was performed at Assurance level 1 according to ASTM D 4169-16, and the results are shown in Table 4 below. Specifically, the first drop, first vibration, second vibration, and second drop were performed under the conditions below, and the breakage rate such as pinholes or tears was calculated to evaluate distribution stability.

[0167] - 1st drop method and number of times: 2 corner drops, 2 apex drops, 2 surface drops (1 top, 1 bottom) a total of 6 drops from 533 mm

[0168] - 1st box compression load and time: Example 2-2 625.9 kgf, 3 sec / Comparative Example 2-1 624.5 kgf, 3 sec

[0169] - 1st vibration: Truck low level 40 min -> Truck Medium level 15 min -> Truck High level 5 min

[0170] - Secondary vibration: Same as first vibration

[0171] - Secondary box compression load and time: 186.3 kgf, 2 sec for both Example 2-2 and Comparative Example 2-2

[0172] - Secondary drop method and number of times: Dropped once from the top, twice from the corner, and twice from the side with a drop height of 533 mm, then dropped on the floor with a drop height of 1066 mm

[0173]

[0174] Film for packaging of food compartments. Packaging of food compartments. Puncture strength (kgf). Distribution stability evaluation (breakage rate, %). Outside. Inside. Example 1-20.50.7. Example 2-20. Comparative example 1-20.50.7. Comparative example 2-23.3.

[0175]

[0176] As shown in Table 4 above, the food packaging film of Example 1-2 exhibited mechanical properties equivalent to those of Comparative Example 1-2, a conventional food packaging film manufactured to the same thickness, despite the reduced amount of raw materials used.

[0177] In addition, as a result of performing a distribution stability test on the food packaging bodies of Example 2-2 and Comparative Example 2-2 manufactured using the food packaging films of Example 1-2 and Comparative Example 1-2, the food packaging film of Example 2-2 had excellent distribution stability despite the fact that the amount of raw materials used was reduced compared to Comparative Example 2-2, which is a conventional food packaging film. At this time, the breakage rate was calculated as the ratio of food packaging bodies with pinholes or tears among 30 food packaging bodies placed in a box, and in the case of Example 2-2, no breakage occurred, whereas in the case of Comparative Example 2-1, 1 was broken (3.3%).

[0178] [Explanation of symbols]

[0179] 100: Foam film

[0180] 110: Core layer

[0181] 120: Skin layer

[0182] 121: 1st skin layer, 122: 2nd skin layer

[0183] 200: Adhesive layer

[0184] 210: first adhesive layer, 220: second adhesive layer

[0185] 300: Base layer

[0186] 400: Barrier layer

[0187] 500: Print layer

Claims

1. A core layer including a closed cell; and A film for food packaging, comprising a foam film including a skin layer containing a polyethylene component.

2. In paragraph 1, A film for food packaging, wherein the core layer comprises the closed cells in an amount of 40% to 95% by volume based on the total volume of the core layer.

3. In paragraph 1, A film for food packaging, wherein the thickness of the core layer is 20% or more of the total thickness of the foam film.

4. In paragraph 1, The above core layer is, The melting index (MI) is 0.3 to 1.2, Density is 0.7 g / cm 3 0.97 g / cm 3 Film for food packaging.

5. In paragraph 1, A film for food packaging, wherein the core layer comprises at least one selected from the group consisting of polyethylene (PE), ethylene vinyl acetate (EVA), linear low-density polyethylene (LLDPE), low-density polyethylene (LDPE), medium-density polyethylene (MDPE), high-density polyethylene (HDPE), polyolefin elastomer (POE), and polyolefin plastomer (POP).

6. In paragraph 1, A film for food packaging, wherein the above skin layer is an inner layer that comes into contact with food.

7. In paragraph 1, A film for food packaging, wherein the skin layer comprises at least one selected from the group consisting of polyethylene (PE), ethylene vinyl acetate (EVA), linear low-density polyethylene (LLDPE), low-density polyethylene (LDPE), medium-density polyethylene (MDPE), high-density polyethylene (HDPE), polyolefin elastomer (POE), and polyolefin plastomer (POP).

8. In paragraph 1, The thickness of the core layer is 20 ㎛ to 100 ㎛, The thickness of the above skin layer is 10 ㎛ to 100 ㎛, A film for food packaging, wherein the total thickness of the foam film is 30 ㎛ to 250 ㎛.

9. In paragraph 1, The above skin layer includes a first skin layer and a second skin layer, The first skin layer is disposed on one surface of the core layer, The second skin layer is disposed on the other surface of the core layer, A film for food packaging, wherein the first skin layer comes into contact with food.

10. In paragraph 9, A film for food packaging, wherein the thickness ratio of the second skin layer: the core layer: the first skin layer is 1:0.5 to 5:

1.

11. In paragraph 1, The above food packaging film includes a substrate layer, A film for food packaging, wherein the substrate layer comprises at least one selected from the group consisting of nylon (NY), polyethylene (PE), ethylene vinyl acetate (EVA), linear low-density polyethylene (LLDPE), low-density polyethylene (LDPE), medium-density polyethylene (MDPE), high-density polyethylene (HDPE), polyethylene terephthalate (PET), and polypropylene (PP).

12. In paragraph 11, The above skin layer includes a first skin layer and a second skin layer, The above food packaging film is a food packaging film in which the base layer, the second skin layer, the core layer, and the first skin layer are laminated in that order.

13. In paragraph 11, A film for food packaging, wherein the weight ratio of the foam film and the substrate layer is 1:0.1 to 0.

85.

14. In paragraph 11, A film for food packaging, comprising an adhesive layer between the substrate layer and the foam film.

15. In paragraph 1, The above food packaging film includes a barrier layer, A film for food packaging, wherein the barrier layer comprises at least one selected from the group consisting of aluminum, ethylene-vinyl alcohol (EVOH), polyvinylidene chloride (PVDC), and polyvinyl chloride (PVC).

16. In paragraph 1, The above food packaging film includes a printing layer, A film for food packaging, wherein the printing layer comprises at least one selected from the group consisting of polyethylene terephthalate (PET), nylon (NY), and stretched polypropylene (OPP).

17. Food; and Including a food packaging film for sealing the above food, The above food packaging film is a food packaging body comprising a foam film including a core layer including closed cells and a skin layer including a polyethylene component.

18. In paragraph 17, The above food packaging body is a food packaging body having a puncture strength of 0.5 kgf or more and a dart impact strength of 15 kgf or more.

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