Antiviral films and food packaging bags

Abstract

To provide an antiviral film that can be produced with stable quality in efficient and economical manner and is suitable for general uses, and a food wrapping bag that is sufficiently proof against contagion.SOLUTION: A film body consists of two or more layers including a substrate layer 20 and an antiviral layer 30. The film body has an antiviral ability with an antiviral activity value of 2.0 or more against at least one of influenza virus or feline calicivirus in accordance with ISO 21702(2019). The antiviral layer 30 has an antiviral agent of soluble glass containing silver and copper components added thereto in a rate of 1 wt.% or more, the antiviral layer 30 provided as the surface layer of the film body.SELECTED DRAWING: Figure 1

Description

Technical Field

[0001] The present invention relates to an antiviral film and a food packaging bag using the antiviral film.

Background Art

[0002] For example, the history of infectious diseases caused by coronaviruses is long, and in recent years, the MERS virus and the SARS virus are known. Infectious diseases caused by viruses develop when the virus enters the body through the mouth, nose, eyes, etc. The infection routes of viruses are mainly contact infection, droplet infection, airborne infection, etc. Regarding virus infection, research and development of antiviral agents that exhibit an antiviral effect have been carried out, and antiviral agents composed of specific metal elements and organic compounds are in circulation. These antiviral agents are suitably used for products in various fields such as building materials, bedding, paints, and clothing, for example, as a countermeasure against contact infection.

[0003] Currently, the novel coronavirus infection (COVID-19) is spreading worldwide, and in Japan, a large number of infected people have been confirmed every day, and cases of death due to the infectious disease have also been reported. And due to the spread of the novel coronavirus infection, the awareness of infectious disease prevention has increased, and when purchasing products at the store, etc., it is particularly required to be safe, secure, and hygienic.

[0004] For example, in stores such as supermarkets and convenience stores, customers may return the products they have once picked up to the display shelves, and there are also many opportunities for an unspecified number of people to touch the same product. Such contact by an unspecified number of people is becoming a concern for more people as it increases the possibility of contact infection and is not hygienically preferable. Therefore, it is considered that by imparting antiviral properties to the packaging bags of various products such as foods and daily necessities, that is, by imparting antiviral properties to the film-like materials used for the packaging bags, it is possible to respond to contact infection as described above.

[0005] Examples of film-like materials with antiviral properties include those in which an antiviral agent is applied to the film surface to impart antiviral properties. However, there have been quality issues, such as uneven application of the antiviral agent.

[0006] Furthermore, other antiviral films are known in which metal particles, consisting of at least one metal with antiviral properties, Cu and Pd, are scattered in an island-like manner on a base film (see Patent Document 1). In this conventional antiviral film, the metal particles are attached to the film by a spraying process or a transfer process such as an inkjet process to impart an antiviral effect. This antiviral film can be suitably used as a protective film for touch panels, a film for displays, and can also be attached to other appropriate locations that people frequently touch.

[0007] However, this antiviral film is economically expensive due to the complicated processing required to maintain its antiviral properties, making it unsuitable for general use such as packaging bags for food and daily necessities. In particular, there is a need for food packaging bags that adequately address contact transmission in antiviral products. [Prior art documents] [Patent Documents]

[0008] [Patent Document 1] Japanese Patent Publication No. 2018-134753 [Overview of the project] [Problems that the invention aims to solve]

[0009] The present invention has been made in view of the above points, and provides an antiviral film that can be manufactured efficiently, economically, and with stable quality, and is suitable for general use. It also provides a food packaging bag that is suitable for contact transmission. [Means for solving the problem]

[0010] In other words, the invention of claim 1 is a film body composed of two or more layers including a base layer and an antiviral layer, having antiviral performance with an antiviral activity value of 2.0 or higher against at least one of influenza virus or feline calicivirus in accordance with ISO 21702 (2019), wherein the antiviral layer has 1% by weight or more of a soluble glass antiviral agent containing silver and copper components added to the surface layer of the film body. With a thickness of 1.0 to 2.0 μm The present invention relates to an antiviral film characterized by having a feature and having a haze value of 7% or less.

[0011] The invention of claim 2 relates to the antiviral film according to claim 1, wherein the antiviral agent content in the antiviral layer is 3 to 6% by weight.

[0012] Claim 3 The invention is as described in claim 1, where the film body is a food packaging film. or 2 This relates to the antiviral film described above.

[0013] Claim 4 The invention is claimed 3 This relates to a food packaging bag characterized by being composed of the antiviral film described above. [Effects of the Invention]

[0014] The antiviral film according to claim 1 is composed of two or more layers including a substrate layer and an antiviral layer, and is a film having antiviral performance with an antiviral activity value of 2.0 or higher against at least one of influenza virus or feline calicivirus in accordance with ISO 21702 (2019), wherein the antiviral layer has 1% by weight or more of a soluble glass antiviral agent containing silver and copper components added to the surface layer of the film. With a thickness of 1.0 to 2.0 μmIt is provided, and since the haze value of the film body is 7% or less, it can be manufactured more efficiently at a lower cost than in the past, the quality can be stabilized, and an antiviral film suitable for general use can be provided. In particular, it is suitable as a transparent film for packaging foods and the like.

[0015] According to the antiviral film according to the invention of claim 2, in the invention of claim 1, since the content of the antiviral agent in the antiviral layer is 3 to 6% by weight, appropriate antiviral performance can be ensured.

[0016] Claim 3 According to the antiviral film according to the invention of, in the invention of claim 1 or 2 Since the film body is a film for food packaging, a packaging bag having a structure suitable for food packaging can be manufactured.

[0017] Claim 4 According to the food packaging bag according to the invention of, claim 3 Since it is composed of the antiviral film described in, a food packaging bag having a structure that effectively responds to contact infection can be provided.

Brief Description of the Drawings

[0018] [Figure 1] It is a schematic cross-sectional view of an antiviral film according to an embodiment of the present invention. [Figure 2] It is a schematic cross-sectional view of a food packaging bag using the antiviral film of FIG. 1.

Modes for Carrying Out the Invention

[0019] The antiviral film 10 according to one embodiment of the present invention shown in Figure 1 is a film body having antiviral performance with an antiviral activity value of 2.0 or higher, and is composed of two or more layers including a base layer 20 and an antiviral layer 30. This antiviral film 10 is used in various film products such as packaging bags, and is particularly suitable for use as a film material for packaging bags that package bread, rice balls, fresh foods, processed foods, confectionery, and other goods handled in stores such as supermarkets and convenience stores, as well as daily necessities.

[0020] In antiviral film 10, the antiviral activity value is a criterion for determining the antiviral performance of an antiviral processed product. The antiviral activity value of non-textile antiviral processed products such as plastic and ceramic products is calculated using an antiviral test method compliant with ISO 21702 (2019). According to the Society of International Antimicrobial Agents for Products (SIAA), the antiviral performance of antiviral film 10 is based on the requirement that the antiviral activity value of the antiviral processed product be 2.0 or higher. In particular, this antiviral activity value is the value against at least one of influenza virus or feline calicivirus. That is, if the antiviral activity value is 2.0 or higher against either influenza virus or feline calicivirus, it is recognized as an antiviral processed product. When the antiviral activity value is 2.0 or higher, the virus removal rate is 99% or higher.

[0021] The base layer 20 is the main resin layer of the film 10. This base layer 20 is made of a suitable resin material that is suitable for use in food packaging and the like. For example, polyolefin resins are preferably used, and polypropylene resins, which are inexpensive and highly versatile, are more preferable. Polypropylene resins are selected from polymers mainly composed of propylene, such as homopolypropylene (a homopolymer of propylene) or copolymers of propylene with other olefins such as ethylene or butene (propylene copolymers).

[0022] The antiviral layer 30 is a resin layer that imparts antiviral performance to the film 10, and is provided on the surface layer of the film body with an antiviral agent added in an amount of 1% by weight or more. The surface layer of the film body is the outermost layer of the antiviral film 10, and corresponds to the surface layer and the back layer. In the example shown in Figure 1, the antiviral layer 30 is formed only on the surface layer of one side of the base layer 20, that is, on one surface (surface layer) of the film 10. The antiviral layer 30 is made of a suitable resin material suitable for use in food packaging, etc., and from the viewpoint of adhesive strength with the base layer 20, it is preferable to make it mainly of the same type of resin material as the base layer 20.

[0023] The antiviral agent is an additive that imparts antiviral properties and consists of soluble glass containing silver and copper components with antiviral effects. The antiviral properties imparted by the antiviral agent are enhanced according to the amount contained in the resin material constituting the antiviral layer 30, and a content of 1% by weight or more is sufficient to obtain the required antiviral performance. However, if the antiviral agent content is too high, the transparency of the film 10 tends to deteriorate (the haze value increases). Also, since the antiviral agent contains metal components, if the content in the resin material is high, there is a risk of a phenomenon called copper damage occurring, which accelerates the oxidative degradation of the resin. Copper damage can be suppressed by additives, but these additives are expensive and may reduce transparency. Therefore, in order to ensure appropriate antiviral performance, the antiviral agent content in the antiviral layer 30 is preferably 3 to 6% by weight.

[0024] In the antiviral layer 30, as shown in Figure 1, the antiviral effect is exerted by the antiviral agent 35 being appropriately exposed from the layer surface 31. In this embodiment, since the antiviral agent 35 has a particle size of about 2.5 μm, it is preferable that the antiviral layer 30 be formed to a thickness of 1.0 to 2.0 μm in order to ensure adequate antiviral performance. If the thickness of the antiviral layer 30 is less than 1.0 μm, the antiviral agent 35 may fall off from the antiviral layer 30, and if it is thicker than 2.0 μm, there may be a large amount of antiviral agent 35 that is not exposed from the layer surface 31, which may prevent a sufficient antiviral effect from being obtained.

[0025] In this antiviral film 10, in addition to the base layer 20 and the antiviral layer 30, an appropriate resin layer may be formed as needed. The other resin layer is made of an appropriate resin material suitable for food packaging, etc., and from the viewpoint of adhesive strength with the base layer 20, it is preferable that it be mainly made of the same type of resin material as the base layer 20. The other resin layer is formed between the base layer 20 and the surface layer (outermost layer) antiviral layer 30, or on the other side (back side) if the antiviral layer 30 is only on one side (front side). Furthermore, depending on the application, multiple layers of the other resin layer may be formed, or they may be formed on both sides of the base layer 20. In the illustrated film 10, the back layer 40 is formed on the other side of the base layer 20.

[0026] The above-mentioned film 10 is formed to a predetermined thickness by melting the resins constituting each layer and using known manufacturing techniques such as the T-die method or the inflation method. Furthermore, when polypropylene resin is used for the base layer 20 or the antiviral layer 30, it is preferable to form the film using a known uniaxial stretching method or biaxial stretching method. The stretched polypropylene film has excellent transparency and high mechanical strength, resulting in excellent printability and bag-making properties, making it suitable as a film for food packaging.

[0027] Furthermore, in film 10, known additives such as antifogging agents, antistatic agents, antioxidants, light stabilizers, lubricants, and antiblocking agents may be appropriately added to one or more layers of each layer as needed. When used as a food packaging film, it is preferable to add antifogging agents and antiblocking agents. As antifogging agents, one or more types of alkyldiethanolamine, alkyldiethanolamine fatty acid esters, glycerin fatty acid esters, etc., which are used in known antifogging films are used, and a mixture of the three listed antifogging agents is particularly preferred. As antiblocking agents, one or more types of known inorganic silica or organic cross-linked acrylic beads are used.

[0028] In the film 10, it is preferable to have high transparency in order to obtain a good appearance. Transparency is evaluated, for example, by the level of the haze value. The haze value is an indicator of the cloudiness of the film and is measured in accordance with JIS K 7136 (2000), with lower values ​​indicating higher transparency. Therefore, it is preferable that the haze value of the film 10 be 7% or less. When the haze value of the film 10 is 7% or less, a transparent film can be made, which is particularly suitable for packaging food and the like. If the haze value exceeds 7%, the transparency of the film itself is lost, and the visibility required, especially for packaging food and the like, may be impaired.

[0029] Furthermore, the surface of film 10 may be subjected to corona treatment as needed. The wetting tension of the film surface due to corona treatment is preferably 36 mN / m to 44 mN / m. If the wetting tension is less than 36 mN / m, the anti-fogging properties may not be sufficiently developed, or the adhesion of printing inks may be poor when printing is performed. If it exceeds 44 mN / m, the bleed-out of the anti-fogging agent to the surface may increase, potentially causing whitening or blocking of the film.

[0030] The antiviral film 10 of the present invention is constructed by adding an antiviral agent to a resin material to form an antiviral layer 30. Therefore, it can be manufactured more efficiently and at a lower cost than conventional antiviral films, such as those in which an antiviral agent is applied to the surface of the film, and quality can be stabilized by avoiding uneven coating. Furthermore, if the antiviral layer 30 is formed only on one side of the substrate layer 20, i.e., on one side (front side) of the film 10, the film 10 is configured so that antiviral performance is provided on one side (front side) and the other side (back side) has other functions. This makes it possible to use it in a variety of applications and provides an antiviral film suitable for general use. Moreover, if the antiviral layer 30 is formed on both sides of the film 10, antiviral performance can be provided on both sides of the film 10.

[0031] In particular, the antiviral film 10 of the present invention is suitable for food packaging when antiviral properties are applied to only one side (the surface side). That is, as shown in the food packaging bag 50 in Figure 2, the inner surface 51 side, which comes into contact with the contents (food) C, is the side without antiviral properties, while the outer surface 52 side, which does not come into contact with the contents C but is touched by human hands, etc., is the side with antiviral properties. In the illustrated embodiment, the inner surface 51 side of the packaging bag 50 corresponds to the back layer 40 of the film 10, and the outer surface 52 side corresponds to the antiviral layer 30 of the film 10.

[0032] This food packaging bag 50 can be given antiviral properties to the entire outer surface 52 that may come into contact with human hands, etc. Therefore, it can be made into a structure that is extremely effective in preventing contact infection. The food packaging bag 50 is used to package the contents C of food, etc., using known packaging methods such as pillow packaging or three-sided seal packaging. [Examples]

[0033] [Preparation of antiviral films] For prototypes 1-10, based on the resin blending ratio (weight %) described later, resin pellets and other raw materials were supplied to an extruder for melting and kneading. The films were then co-extruded using a T-die film molding machine that co-extrudes three layers at once, and a biaxial stretcher was used to produce films with a stretch ratio of 5 times in the longitudinal (winding direction, MD) and 8 times in the transverse (axial direction, TD). After film formation, both surface layers were subjected to corona treatment under conditions commonly used for films. Each of prototypes 1-10 consists of three layers: a base layer, a surface layer formed on one side (front side) of the base layer, and a back layer formed on the other side (back side) of the base layer. The antiviral agent was added to the surface layer.

[0034] [Resin materials] Each layer constituting the film was made using one of the following resin materials: (PP1) to (PP6). • Resin PP1: Homopolypropylene resin (manufactured by Nippon Polypropylene Co., Ltd., "FL203D") • Resin PP2: An anti-fogging masterbatch consisting of 8% by weight of an anti-fogging agent composed of 40% by weight of glycerin monostearate, 20% by weight of oleyl diethanolamine, and 40% by weight of stearyl diethanolamine monostearate, and resin PP1, melt-kneaded together in a ratio of 92% by weight. • Resin PP3: Random polypropylene resin (manufactured by Nippon Polypropylene Co., Ltd., "FX4E") • Resin PP4: A masterbatch made by melt-kneading PP3 resin at a ratio of 90% by weight and soluble glass containing silver and copper components (Ishizuka Glass Co., Ltd., "GlassAC01") at a ratio of 10% by weight. • Resin PP5: A masterbatch made by melt-kneading 90% by weight of resin PP3 and 10% by weight of soluble glass containing silver (Ishizuka Glass Co., Ltd., "Ion Pure WPA"). • Resin PP6: A masterbatch made by melt-kneading PP3 resin at a ratio of 90% by weight and soluble glass containing silver (Ishizuka Glass Co., Ltd., "Ion Pure ZAF HS") at a ratio of 10% by weight.

[0035] [Prototype Example 1] Prototype Example 1 is a biaxially oriented film with a thickness of approximately 20 μm, composed of a base layer extruded at 240°C using resin PP1, a surface layer extruded at 200°C from a mixture of resin PP3 and resin PP4 in a ratio of 50% by weight, and a back layer extruded at 240°C using resin PP1. In the film of Prototype Example 1, the extrusion amounts of each raw material were adjusted so that the thickness of each layer was in the ratio of surface layer / base layer / back layer to 2 / 17 / 1. In addition, the total amount of soluble glass in the surface layer of the film of Prototype Example 1 is 5.0% by weight.

[0036] [Prototype Example 2] Prototype Example 2 is a biaxially oriented film with a thickness of approximately 20 μm, constructed in the same manner as Prototype Example 1, except that the base layer is composed of a mixture of resin PP1 at a ratio of 87.5% by weight and resin PP2 at a ratio of 12.5% ​​by weight. In the film of Prototype Example 2, the total amount of soluble glass in the surface layer is 5.0% by weight. In addition, the total amount of antifogging agent in the base layer is 1.0% by weight.

[0037] [Prototype Example 3] Prototype Example 3 is a biaxially oriented film with a thickness of approximately 20 μm, composed of a base layer extruded at 240°C using resin PP1, a surface layer extruded at 200°C using resin PP3, and a back layer extruded at 240°C using resin PP1. In the film of Prototype Example 3, the extrusion amounts of each raw material were adjusted so that the thickness of each layer was in the ratio of 1 / 18 / 1 for the surface layer / base layer / back layer.

[0038] [Prototype Example 4] Prototype Example 4 is a biaxially oriented film with a thickness of approximately 20 μm, composed of a base layer extruded at 240°C using resin PP1, a surface layer extruded at 200°C from a mixture of resin PP3 and resin PP5 in a ratio of 50% by weight, and a back layer extruded at 240°C using resin PP1. In the film of Prototype Example 4, the extrusion amounts of each raw material were adjusted so that the thickness of each layer was in the ratio of surface layer / base layer / back layer of 1 / 18 / 1. In addition, the total amount of soluble glass in the surface layer of the film of Prototype Example 4 is 5.0% by weight.

[0039] [Prototype Example 5] Prototype Example 5 is a biaxially oriented film with a thickness of approximately 20 μm, constructed in the same manner as Prototype Example 2, except that the base layer is made of resin PP1 and the surface layer is made of a mixture of resin PP3 and resin PP6 in a ratio of 50% by weight. In the film of Prototype Example 5, the total amount of soluble glass in the surface layer is 5.0% by weight.

[0040] [Prototype Example 6] Prototype 6 is a biaxially oriented film with a thickness of approximately 20 μm, constructed in the same manner as Prototype 3, except that the base layer is composed of a mixture of resin PP1 at a ratio of 53.8% by weight and resin PP2 at a ratio of 46.2% by weight. In the film of Prototype 6, the total amount of antifogging agent in the base layer is 3.7% by weight.

[0041] [Prototype Example 7] Prototype Example 7 is a biaxially oriented film with a thickness of approximately 20 μm, constructed in the same manner as Prototype Example 3, except that the base layer is made of resin PP1 and the surface layer is made of a mixture of resin PP3 at a ratio of 90% by weight and resin PP4 at a ratio of 10% by weight. In the film of Prototype Example 7, the total amount of soluble glass in the surface layer is 1.0% by weight.

[0042] [Prototype Example 8] Prototype 8 is a biaxially oriented film with a thickness of approximately 20 μm, constructed in the same manner as Prototype 3, except that the base layer is made of resin PP1 and the surface layer is made of a mixture of resin PP3 (70% by weight) and resin PP4 (30% by weight). In the film of Prototype 8, the total amount of soluble glass in the surface layer is 3.0% by weight.

[0043] [Prototype Example 9] Prototype 9 is a biaxially oriented film with a thickness of approximately 20 μm, constructed in the same manner as Prototype 3, except that the base layer is made of resin PP1 and the surface layer is made of a mixture of resin PP3 and resin PP4 in a ratio of 50% by weight. In the film of Prototype 9, the total amount of soluble glass in the surface layer is 5.0% by weight.

[0044] [Prototype Example 10] Prototype 10 is a biaxially oriented film with a thickness of approximately 20 μm, constructed in the same manner as Prototype 3, except that the base layer is made of resin PP1 and the surface layer is made of a mixture of resin PP3 (30% by weight) and resin PP4 (70% by weight). In the film of Prototype 10, the total amount of soluble glass in the surface layer is 7.0% by weight.

[0045] [Evaluation of the performance of antiviral films] Using prototype films 1-10, the film thickness (μm), haze (%), and antiviral activity value were measured and their performance evaluated. In the overall performance evaluation of the antiviral film, a rating of "Unacceptable (×)" was given if the antiviral activity value was judged to be "Acceptable (〇)" or better if the antiviral activity value was judged to be "Acceptable (〇)" or better, and "Excellent (◎)" was given if both the antiviral activity value and haze were judged to be "Good". The results are shown in Tables 1 and 2 below. Tables 1 and 2 also include the total amount (weight %) of soluble glass contained in the surface layer and the metal component.

[0046] [Measuring the thickness of the film] The overall thickness of each film from prototype examples 1 to 10 was measured in accordance with JIS K 7130 (1999).

[0047] [Measurement of haze] Haze (%) measurement is an indicator of transparency and was performed in accordance with JIS K 7136 (2000) using a haze meter (NDH-5000, manufactured by Nippon Denshoku Industries Co., Ltd.). For prototype examples 1 to 10, since the films are intended for food packaging and require transparency that allows the contents to be visible during packaging, a measurement result of 7% or less was rated as "Good (〇)" and a result greater than 7% was rated as "Unacceptable (×)".

[0048] [Measurement of antiviral activity levels] The antiviral activity value is calculated using an antiviral test method compliant with ISO 21702 (2019). The antiviral test method involves first inoculating a 50mm x 50mm test piece with 0.4ml of a pre-prepared virus suspension, covering it with a 40mm x 40mm cover film, and allowing it to stand for 24 hours at 25°C and 90% RH or higher to allow the virus and sample to react. Subsequently, 10ml of wash solution (SCDLP medium) is added to recover the virus from the sample, and the recovered virus is cultured to measure the viral infectivity titer. This antiviral test allows the use of one or more viruses, including influenza A virus and feline calicivirus. Influenza A virus is an enveloped type of virus, and the novel coronavirus also belongs to this type. Feline calicivirus is a non-enveloped type of virus and is a surrogate virus for norovirus. In the examples, influenza A virus (H3N2) and feline calicivirus (F-9) were used.

[0049] Viral infectivity titer (PFU / cm²) 2 The number of plaques in each well of the dilution series in which 6 to 60 plaques appeared after virus culture is measured and calculated using the following formula. Viral infectivity titer / 0.1ml (PFU / 0.1ml) = number of plaques × dilution ratio Viral infectivity titer / ml (PFU / ml) = number of plaques × dilution ratio × 10 Viral infectivity titer / 1cm 2 (PFU / cm 2 ) = (Viral infectivity titer / ml) × (Amount of washout solution) ÷ (Cover film area)

[0050] Based on the measured viral infectivity titer, the antiviral activity value is calculated using the following formula. Then, based on the criteria established by SIAA, if the antiviral activity value calculated using the following formula is 2.0 or higher for both influenza virus and feline calicivirus, it is classified as "Good (◎)", if either influenza virus or feline calicivirus is 2.0 or higher, it is classified as "Acceptable (〇)", and if both influenza virus and feline calicivirus are less than 2.0, it is classified as "Unacceptable (×)". R = Ut - At R: Antiviral activity value Ut: Viral infectivity titer (PFU / cm²) of unprocessed samples after 24 hours of standing. 2 The average of the common logarithms of ) At: Viral infectivity titer (PFU / cm²) of antiviral treated product after 24 hours of standing. 2 ) the average of the common logarithms

[0051] [Table 1]

[0052] [Table 2]

[0053] [Results and Discussion] As shown in Table 1, the overall evaluations were "Good (◎)" for prototypes 1, 2, 8, and 9, "Acceptable (〇)" for prototypes 7 and 10, and "Unacceptable (×)" for prototypes 3 to 6. Of the films from prototypes 3 to 6 that received an overall evaluation of "Unacceptable," the film in prototype 3 had a surface layer that did not contain an antiviral agent (soluble glass), and the films in prototypes 4 and 5 used soluble glass with only silver as the metal component as the antiviral agent in the surface layer, resulting in extremely low antiviral activity values ​​for all of them. The film in prototype 6 was a film with an excessive amount of antifogging agent added to the base layer. It was expected that antiviral performance would be exhibited by excessively bleeding out the antifogging agent to the film surface, but no antiviral effect was obtained at all.

[0054] In contrast, prototype examples 1, 2, 8, and 9, which received an overall evaluation of "Good," used soluble glass containing silver and copper metal components as antiviral agents in the surface layer. From this, it was found that soluble glass containing silver and copper components is preferable as an antiviral agent added to the surface layer.

[0055] The film of prototype example 10, which received an overall evaluation of "acceptable," also used soluble glass with silver and copper metal components as antiviral agents in its surface layer. It was found to have high antiviral activity and good antiviral effect. However, the film of prototype example 10 had a high haze value, resulting in slightly impaired transparency. Therefore, the film of prototype example 10 is not very suitable for use as a transparent film, but it can be used well as an antiviral film when transparency is not required. The film of prototype example 7, which also received an overall evaluation of "acceptable," had slightly insufficient antiviral activity against influenza virus, but its antiviral activity against feline calicivirus exceeded the standard value, so it can be used appropriately as an antiviral film.

[0056] Furthermore, of the two prototype films, Prototype 1 and 2, which received an overall evaluation of "Good," Prototype 2 is a film in which an antifogging agent has been added to the base layer. This Prototype 2 film achieved the same antiviral activity value as Prototype 1, which did not have an antifogging agent added. It was thought that the antifogging agent might hinder the antiviral effect because it tends to rise to the surface of the film when added, but as can be seen from Prototypes 1 and 2, it was shown that appropriate antiviral performance can be obtained even when an appropriate amount of antifogging agent is added. [Industrial applicability]

[0057] The antiviral film of the present invention has an antiviral layer formed on the surface of the film body by adding an antiviral agent of soluble glass containing silver and copper components. As a result, it can be manufactured more efficiently and at a lower cost than conventional methods, while maintaining stable quality. Furthermore, this antiviral film is suitable for general use, and in particular, when used as a food packaging film, it can provide food packaging bags with a structure that effectively addresses contact infection. [Explanation of symbols]

[0058] 10 Antiviral film 20 Base material layer 30 Antiviral layer 31 layer surface 35 Antiviral agents 40 Back layer 50 Food packaging bags 51. The inner surface of food packaging bags 52 Outer surface of food packaging bags C Contents

Claims

1. A film comprising two or more layers including a base layer and an antiviral layer, having antiviral performance with an antiviral activity value of 2.0 or higher against at least one of influenza virus or feline calicivirus in accordance with ISO 21702 (2019), The antiviral film is characterized in that the antiviral layer is provided on the surface of the film body to a thickness of 1.0 to 2.0 μm with an antiviral agent of soluble glass containing silver and copper components added in an amount of 1% by weight or more, and the haze value of the film body is 7% or less.

2. The antiviral film according to claim 1, wherein the antiviral agent content in the antiviral layer is 3 to 6% by weight.

3. The antiviral film according to claim 1 or 2, wherein the film body is a film for food packaging.

4. A food packaging bag characterized by being composed of the antiviral film described in claim 3.

Images