Food preservation packaging material and production method thereof

Abstract

To provide a packaging material for preserving freshness capable of safely preserving quality of fresh foods and processed foods over a long time by preventing proliferation of mold in a circulation process of the fresh foods and processed foods.SOLUTION: A method for producing a food preserving packaging material containing a main material, zinc oxide, and an organic fungicide and charged with static electricity, comprises: installing with a mixture containing a main material, zinc oxide, and an organic anti-fungal agent or a packaged material after molding the mixture contacted with a metal plate having conductivity; and charging by inputting a voltage to the metal plate.SELECTED DRAWING: Figure 3

Description

[Technical field]

[0001] The present invention relates to a packaging material for food preservation used for foods such as fresh vegetables, fruits, raw meat, raw fish, flowers, and processed foods, and a method for producing the same. [Background technology]

[0002] Our current diet and lifestyles have changed significantly due to the spread of COVID-19. As restrictions such as restrictions on going out become more stringent, there is a greater need to maintain the quality and safety of food ingredients for longer than ever before.

[0003] As exemplified by the Sustainable Development Goals, reducing food waste has become an important social issue. There is a greater demand than ever for container and packaging materials that can preserve food ingredients safely for long periods of time.

[0004] A wide variety of freshness preservation technologies based on zinc oxide have been proposed so far. For example, JP 2014-12752 A discloses a resin-containing paper composition containing an antibacterial composition in which silica-coated calcined shell calcium is mixed with powder particles of silica-coated zinc oxide and silica-coated titanium oxide as secondary components in such a way that the silica-coated zinc oxide and silica-coated titanium oxide are each a maximum of 15% by mass relative to the total mass of the silica-coated calcined shell calcium (Patent Document 1).

[0005] In addition, JP 2022-022479 A discloses a freshness-preserving film made of a resin that has properties that make it difficult for oxygen and water vapor to pass through, and contains zinc oxide in which the photocatalytic active sites are coated with a coating agent (Patent Document 2).

[0006] Furthermore, a freshness-preserving film has been disclosed that has a first layer, a second layer, and a third layer, and the first layer 1 of the freshness-preserving film contains zinc oxide whose photocatalytic active sites are coated with a coating agent in a resin that has properties that make it difficult for oxygen and water vapor to pass through.This enables the film to efficiently decompose ethylene generated from food (particularly fresh produce, fruits, vegetables, etc.) and non-food plants into water and carbon dioxide molecules not only under light conditions but also in dark places (Patent Document 3). [Prior art documents] [Patent documents]

[0007] [Patent Document 1] JP 2014-12752 A [Patent Document 2] Patent Publication No. 2022-022479 [Patent Document 3] International Publication No. 2020 / 080542 Summary of the Invention [Problem to be solved by the invention]

[0008] Up until now, zinc oxide and coated zinc oxide have been studied for their freshness-preserving effect mainly through the decomposition of ethylene gas, i.e., for regulating the ripening of vegetables and fruits that do not contain processed foods by ethylene gas. However, little research has been done on the decay phenomenon caused by mold, which is another cause of quality deterioration in fresh and processed foods, and there has been a demand for the development of packaging materials with high mold prevention effects for freshness preservation. [Means for solving the problem]

[0009] As a result of extensive research, the inventors have found that when zinc oxide microparticles are mixed with an organic anti-fungal agent and the mixture is kneaded into a synthetic resin to form a film, the film exhibits a more effective anti-fungal effect than a film to which an organic anti-fungal agent is added alone.

[0010] The present invention has been made based on such findings, and provides a packaging material for food preservation, which is characterized by containing a main material, zinc oxide, and an organic anti-fungal agent.

[0011] The present invention also provides at least one type of food selected from the group consisting of fresh vegetables, fruits, raw meat, raw fish, flowers, and processed foods, packaged in the food preservation packaging material.

[0012] Furthermore, the present invention provides a method for producing a packaging material for food preservation which contains a main material, zinc oxide, and an organic anti-fungal agent and is charged with static electricity, the method comprising the steps of placing a mixture containing the main material, the zinc oxide, and the organic anti-fungal agent, or a packaging material after molding of the mixture, on a conductive metal plate, and a charging step of applying a voltage to the metal plate. Effect of the Invention

[0013] According to the present invention, it is possible to provide a food preservation packaging material having a higher antifungal effect than when zinc oxide or an organic antifungal agent is added alone, which can also contribute to reducing food waste. [Brief description of the drawings]

[0014] [Figure 1] 1A to 1C are diagrams for explaining a manufacturing method of a food preservation packaging material according to the present embodiment. [Diagram 2] 1 shows the results of an antifungal test carried out using the food preservation packaging material (storage bag) of this embodiment. [Diagram 3] 1 shows the results of an anti-mold test carried out using the food preservation packaging material (cocoon ball cushioning material) of this embodiment. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0015] First, a food preservation packaging material according to an embodiment of the present invention will be described. The food preservation packaging material according to this embodiment is characterized by containing a main material, zinc oxide, and an organic antifungal agent.

[0016] In this embodiment, the packaging material for food preservation refers to an object formed into any one of the shapes of a sheet, a bag, a cylinder, a box, and a cocoon ball, and used for the purpose of preserving food for a certain period of time. By making zinc oxide and an organic antifungal agent coexist in the main material of the packaging material, a superior antifungal effect is exhibited compared to when the packaging material is manufactured using each agent alone.

[0017] Zinc oxide is an oxide of zinc represented by the chemical formula ZnO. From the viewpoint of more efficient activation, the primary particle size of zinc oxide is preferably 60 μm or less, and more preferably 5 to 20 μm.

[0018] In addition, as long as the effects of the present invention are not impaired, one or more of the following inorganic oxides may be used in combination with zinc oxide: titanium oxide, magnesium oxide, silver oxide, silicon oxide, aluminum oxide, manganese oxide, copper oxide, and calcium oxide.

[0019] The active ingredient of the organic antifungal agent is preferably at least one selected from the group consisting of 3-iodo-2-propynyl butylcarbamate, paraoxybenzoic acid esters, carbendazim, imazalil, thiabendazole, orthophenylphenol, methylsulfonyltetrachloropyridine, sodium diacetate, and biphenyl.

[0020] The content of the organic antifungal agent is preferably 0.05 to 30% by weight, more preferably 0.1 to 10% by weight, and even more preferably 0.5 to 5% by weight, from the viewpoint of exerting the antifungal effect.

[0021] The main material may be any material that has been used conventionally as a raw material for packaging materials, and is preferably at least one selected from the group consisting of polyethylene, polypropylene, polybutylene, paper, polyvinyl chloride, polyvinylidene chloride, polyamide, polyester, polystyrene, and polyvinyl alcohol.

[0022] The mixing ratio of zinc oxide to the organic anti-fungal agent is preferably 0.1-90% by weight of zinc oxide to 10-99.9% by weight of the organic anti-fungal agent, and more preferably 20-50% by weight of zinc oxide to 50-80% by weight of the organic anti-fungal agent.

[0023] Furthermore, from the viewpoint of the antifungal effect, the blending ratio of the mixture of zinc oxide and the organic antifungal agent to the main material is preferably 0.2 to 30% by weight, more preferably 0.4 to 10% by weight, and even more preferably 0.5 to 5% by weight.

[0024] The mixture of zinc oxide and the organic antifungal agent may be added to the main material by kneading the mixture into the main material, or by spraying or applying the mixture to a packaging material formed into a film or the like.

[0025] The food packaging material according to this embodiment is preferably further electrostatically charged. By electrostatically charging the food packaging material, the mold prevention effect of the food packaging material can be further improved.

[0026] The mechanism by which static electricity improves the antifungal effect is not entirely clear, but it is thought that when zinc oxide, an inorganic oxide, absorbs external electromagnetic energy, the organic antifungal agent is activated by the generation of active oxygen due to exposure to electromagnetic waves in the near-infrared to far-infrared range, and by interactions due to oxidizing power and redox action caused by ion or electron transfer reactions.

[0027] Therefore, since static electricity only needs to be applied to the mixture of zinc oxide and the organic anti-fungal agent, the food packaging material may be charged when it is in the state of being molded into the desired shape, or the mixture of zinc oxide and the organic anti-fungal agent (master batch) before being molded into the desired shape, or the mixture of the zinc oxide and the organic anti-fungal agent and the main material (raw material pellets) may be charged.

[0028] Next, a method for producing a food packaging material according to an embodiment of the present invention will be described. The method for producing a food packaging material according to this embodiment includes a step of placing a mixture containing a main material, the zinc oxide, and the organic antifungal agent, or a packaging material obtained by forming the mixture, in contact with a conductive metal plate, and a step of applying a voltage to the metal plate.

[0029] 1 is a diagram for explaining a method for applying a voltage to a workpiece in this embodiment. An apparatus 10 for applying a voltage to a workpiece 1 is composed of an insulator 3, a conductive metal plate 2 placed on the insulator 3, and a voltage device 4 electrically connected to the metal plate 2.

[0030] The object 1 to be treated is a packaging material such as a molded film or bulk cushioning material, but may also be a masterbatch in which a mold inhibitor or filler has been added to a base resin before being molded into a packaging material. There is no particular limit to the shape of the masterbatch, and it may be in the form of a powder, granules (pellets), or liquid.

[0031] The metal plate 2 is for charging the workpiece 1 with the voltage applied from the voltage device 4, and is made mainly of a conductive metal. Examples of conductive metals include gold, silver, copper, iron, and aluminum. The shape is not particularly limited, but examples include a plate-shaped metal.

[0032] The insulator 3 is intended to prevent static electricity charged on the workpiece 1 from being grounded, and is made of a non-conductive material. Examples of non-conductive materials include plastic, rubber, glass, and ceramic.

[0033] The voltage device 4 includes a step-up chopper circuit and applies a high voltage to the workpiece 1 via the metal plate 2, and a commercially available DC / DC converter can be used for this purpose.

[0034] When applying a voltage, a terminal induced from a voltage device 4 is connected to the metal plate 2, and the voltage is applied through the terminal from the voltage device 4. The workpiece 1, such as a film, is placed on the metal plate 2, and a voltage is applied for a predetermined period of time. At this time, the larger the contact area of ​​the workpiece 1 with the metal plate 2, the more preferable, but it is sufficient that at least a portion of the workpiece 1 is in contact with the metal plate 2.

[0035] When applying voltage, it is important to create a base between the ground and the ground using an insulator 3 such as rubber, which is a highly insulating material, to keep the applied voltage from being earthed. A simple method is to use an insulating plastic pallet as a substitute for the base.

[0036] In this embodiment, the voltage to be applied is preferably within the range of 5,000 to 30,000 volts, and the current is preferably 50 milliamperes or less.

[0037] In this embodiment, the charging step is preferably carried out for 1 hour or more, and more preferably for 24 to 72 hours.

[0038] To check that the voltage is being applied without any problems, use a Fluke Corporation industrial multimeter to measure and verify that a voltage of 5,000 volts or more is being applied.

[0039] The method of applying the voltage is not limited to the method described in the present invention, and other methods can be applied without departing from the spirit of the present invention.

[0040] The present invention will be described in more detail below by way of examples, but the present invention is not limited thereto. EXAMPLES

[0041] 1. Food storage bags (1) Material The main materials used were low-density polyethylene resin (LDPE, manufactured by Japan Polyethylene Corporation), zinc oxide (NANOFINE-50 (trademark), manufactured by Sakai Chemical Industry Co., Ltd.), and carbendazium (Mofguard (trademark), manufactured by EP Trading Co., Ltd.) as an organic antifungal agent.

[0042] The sample was prepared as follows: 20% by weight of zinc oxide was added to low-density polyethylene resin (LDPE), mixed thoroughly, heated to 220-240°C and kneaded, and extruded from an extruder to form pellets to produce a master batch containing 20% ​​by weight of zinc oxide (Master Batch A).

[0043] Separately, carbendazim was added to low-density polyethylene resin (LDPE), mixed thoroughly, heated to 220 to 240°C and kneaded, and extruded through an extruder to produce a master batch containing 20% ​​by weight of carbendazim (master batch B).

[0044] (2) Manufacturing of food storage bags For the film of control 1, 5% by weight of master batch A (containing 20% ​​by weight of zinc oxide) was added to low density polyethylene resin (LDPE) and molded by the inflation method, which is a melt extrusion method (Production Example 1). In this way, a food storage bag containing 1% by weight of zinc oxide was manufactured (Production Example 1). The film was molded to a thickness of 30 microns (the film thickness is the same in the other production examples below).

[0045] To prepare a film for control 2, 5% by weight of masterbatch B (containing 20% ​​by weight of carbendazim) was added to low-density polyethylene resin (LDPE), and a food storage bag containing 1% by weight of carbendazim was formed by the inflation method in the same manner as described above (Production Example 2).

[0046] 5% by weight of each of Starbatch A and Masterbatch B was added to a low-density polyethylene film, and the mixture was molded by the inflation method, which is a melt extrusion method, to produce a food storage bag containing 1% by weight of zinc oxide and 1% by weight of carbendazim (Production Example 3).

[0047] Using the device shown in Fig. 1, master batch A and master batch B were subjected to an electrification treatment at 7000 volts for 72 hours. Aluminum was used as the material for metal plate 2, and a plastic pallet was used as the material for insulator 3. Thereafter, 5% by weight of each of the master batches (A and B) was added to a low-density polyethylene film so that the zinc oxide content was 1% by weight and the carbendazim content was 1% by weight, and food storage bags were produced by the inflation method (Production Example 4).

[0048] (3) Anti-mold test (bread) As a verification object for the antifungal test, a commercially available 8-slice bread containing no antifungal agent was used. A suspension of mold spores (approximately 3 × 10 2 A sample of the fungus was inoculated onto the surface of a slice of bread at 4 locations (1 mL / cell). The sliced ​​bread was then placed into each of the food storage bags mentioned above and sealed. The bread was then stored at 25°C and the mold growth was visually observed. As a control, a low-density polyethylene film to which no agent had been added was used (referred to as "control" in the table). The results are shown in Table 1 and Figure 1.

[0049] [Table 1]

[0050] As is clear from Table 1 and Figure 1, the food storage bag of Production Example 3, which contains a mixture of zinc oxide and carbendazim, has a higher antifungal effect than the food storage bag of Production Example 2, which contains only carbendazim. Furthermore, although the food storage bag of Production Example 4 has the same composition of raw materials as Production Example 3, the antifungal effect was significantly improved as a result of being charged with static electricity by the electrostatic charging treatment.

[0051] 2.Cocoon ball cushioning material (1) Material The main materials used were polypropylene resin (manufactured by Sunallomer Co., Ltd.), zinc oxide (NANOFINE-50 (trademark), manufactured by Sakai Chemical Industry Co., Ltd.), and the organic antifungal agent was carbendazium (Mofguard (trademark), manufactured by EP Trading Co., Ltd.). The rice flour used was manufactured by Hinomoto Grain Flour Co., Ltd.

[0052] (2) Manufacturing of cocoon ball cushioning material The control cocoon ball cushioning material was manufactured by adding water to a mixture of 50% by weight polypropylene resin and 50% by weight rice flour, kneading it in a twin-screw extruder at a temperature of 180 to 200°C, compressing and ejecting it to form a cocoon ball-shaped cushioning material (control).

[0053] In addition, 50% polypropylene resin, 48% by weight rice flour, 1% by weight zinc oxide, and 1% by weight carbendazim were thoroughly mixed, and then mixed with polypropylene resin while adding water. The mixture was kneaded in a twin-screw extruder at a temperature of 180 to 200°C, compressed and discharged to form a cocoon-shaped cushioning material (Production Example 5).

[0054] Furthermore, using the device shown in Fig. 1, the cocoon-ball-shaped cushioning material of Production Example 5 was subjected to an electrification treatment at 10,000 volts for 72 hours to produce a statically charged cocoon-ball cushioning material (Production Example 6). Aluminum was used as the material for the metal plate 2, and a plastic pallet was used as the material for the insulator 3.

[0055] (3) Antifungal test (mandarin oranges) As the verification object for the anti-mold test, a commercially available Unshu mandarin orange that had not been treated for anti-mold treatment was used. This mandarin orange was placed in a container filled with each of the aforementioned cocoon ball cushioning materials, and the entire mandarin orange was sealed in the cocoon ball cushioning material. This was stored at 25°C for 74 days, and the mold growth was visually observed. The results are shown in Table 2 and Figure 2.

[0056] [Table 2]

[0057] As is clear from Table 2 and Figure 2, mold grew on mandarin oranges stored in the control and the cocoon ball cushioning material of Production Example 5 by the 74th day. In contrast, no mold growth was observed on the electrostatically treated cocoon ball cushioning material of Production Example 6 even 74 days after the start of the experiment, despite the fact that the raw material composition was the same as that of Production Example 5, and a significant mold prevention effect was observed. [Explanation of symbols]

[0058] 1...Workpiece 2…Metal plate 3...Insulator 4…Voltage device 10...Apparatus for applying voltage

Claims

1. A packaging material for food preservation, comprising a main material, zinc oxide, and an organic anti-fungal agent.

2. The food storage packaging material according to claim 1, further comprising an electrostatic charge.

3. The food preservation packaging material according to claim 1 or 2, wherein the active ingredient of the organic fungicide is at least one selected from the group consisting of 3-iodo-2-propynyl butylcarbamate, paraoxybenzoic acid ester, carbendazim, imazalil, thiabendazole, orthophenylphenol, methylsulfonyltetrachloropyridine, sodium diacetate, and biphenyl.

4. 3. The food preservation packaging material according to claim 1, wherein the main material is at least one selected from the group consisting of polyethylene, polypropylene, polybutylene, paper, polyvinyl chloride, polyvinylidene chloride, polyamide, polyester, polystyrene, and polyvinyl alcohol.

5. 3. A food preservation packaging material obtained by forming the food preservation packaging material according to claim 1 or 2 into any one of the shapes selected from the group consisting of a sheet, a bag, a cylinder, a box, and a cocoon ball.

6. 6. At least one food selected from the group consisting of fresh vegetables, fruits, raw meat, raw fish, flowers, and processed foods, packaged in the food preservation packaging material according to claim 5.

7. A method for producing a food preservation packaging material containing a main material, zinc oxide, and an organic antifungal agent, and being charged with static electricity, comprising the steps of: a step of placing a mixture containing the main material, the zinc oxide, and the organic antifungal agent or a packaging material obtained by forming the mixture in contact with a conductive metal plate; a charging step of applying a voltage to the metal plate; A method for producing a food preservation packaging material comprising the steps of:

8. The method for producing a food storage packaging material according to claim 7, wherein the voltage is in the range of 5,000 to 30,000 volts.

9. The method for producing a packaging material for food preservation according to claim 7 or 8, wherein the charging step is carried out for one hour or more.

10. The method for producing a food preservation packaging material according to claim 7 or 8, wherein the active ingredient of the organic fungicide is at least one selected from the group consisting of 3-iodo-2-propynyl butylcarbamate, paraoxybenzoic acid ester, carbendazim, imazalil, thiabendazole, orthophenylphenol, methylsulfonyltetrachloropyridine, sodium diacetate, and biphenyl.

11. The method for producing a food preservation packaging material according to claim 7 or 8, wherein the main material is at least one selected from the group consisting of polyethylene, polypropylene, polybutylene, paper, polyvinyl chloride, polyvinylidene chloride, polyamide, polyester, polystyrene, and polyvinyl alcohol.

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