JP2024056343A - Wrap film and wrap film container - Google Patents

Abstract

[Problem] To provide a wrap film and its container that have excellent antiviral properties against both influenza A virus and feline calicivirus. [Solution] One aspect of the present invention is a wrap film that contains a thermoplastic resin and an antiviral agent that contains silver and copper, and the content of the antiviral agent is 0.25% by mass or more and 0.95% by mass or less based on the total amount of the wrap film. [Selected Figure] None

Description

The present invention relates to a wrap film and a wrap film container.

Wrap films are widely used not only in homes but also in hotels, restaurants, etc. Since wrap films are usually expected to come into contact with food, it is preferable for them to have antibacterial and antiviral properties. For example, Patent Document 1 describes a wrap film that contains a thermoplastic resin, a colorant, and a silver-based antibacterial agent.

International Publication No. 2020/027188

The wrap film described in Patent Document 1 has antibacterial properties, but as mentioned above, there is also a demand for wrap films that have antiviral properties. For example, such wrap films preferably have antiviral properties against influenza viruses and noroviruses, which may be present in the environment. Thus, some aspects of the present invention aim to provide a wrap film and a container thereof that have excellent antiviral properties against both influenza A virus and feline calicivirus, which is a virus similar to norovirus.

The inventors' research has revealed that even if an antiviral agent is added to a wrap film, effective antiviral properties may not be obtained depending on the type and content of the antiviral agent and the type of virus. The inventors have then discovered that by adding a specific amount of an antiviral agent containing copper and silver to a wrap film, a wrap film with excellent antiviral properties against both influenza A virus and feline calicivirus can be obtained.

Some aspects of the present invention provide the following [1] to [6].
[1] A wrap film containing a thermoplastic resin and an antiviral agent containing silver and copper, wherein the content of the antiviral agent is 0.25% by mass or more and 0.95% by mass or less based on the total amount of the wrap film.
[2] The wrap film according to [1], wherein the thermoplastic resin comprises at least one selected from the group consisting of polyolefin-based resins, polyvinyl chloride-based resins, and polyvinylidene chloride-based resins.
[3] The wrap film according to [1] or [2], containing a plasticizer in an amount of 10% by mass or more and 30% by mass or less based on the total amount of the wrap film.
[4] The wrap film according to any one of [1] to [3], further comprising a glycerin-based anti-fogging agent.
[5] The wrap film according to any one of [1] to [4], which is used for packaging food.
[6] A wrap film container comprising a core, the wrap film according to any one of [1] to [5] wound around the core, and a box for housing the core and the wrap film.

According to some aspects of the present invention, it is possible to provide a wrap film and a container thereof that have excellent antiviral properties against both influenza A virus and feline calicivirus.

FIG. 2 is a perspective view showing a wrap film container according to one embodiment.

The following describes in detail an embodiment of the present invention with reference to the drawings. However, the present invention is not limited to the following embodiment.

[Wrapping film]
The wrap film according to one embodiment contains a thermoplastic resin and an antiviral agent containing silver and copper. The content of the antiviral agent containing silver and copper is 0.25% by mass or more and 0.95% by mass or less based on the total amount of the wrap film. Such a wrap film is a film for wrapping an article, and is particularly suitable for use as a film for wrapping food. The wrap film according to this embodiment can exhibit excellent antiviral properties by mixing a thermoplastic resin and an antiviral agent containing silver and copper such that the content of the antiviral agent containing silver and copper is 0.25% by mass or more and 0.95% by mass or less based on the total amount of the wrap film.

(Thermoplastic resin)
Thermoplastic resins include polyester-based resins such as polyethylene terephthalate, polyethylene naphthalate, and polybutylene terephthalate; polyamide-based resins such as 6-nylon, 6,6-nylon, and 12-nylon; polystyrene-based resins such as butadiene-styrene copolymer, acrylonitrile-styrene copolymer, polystyrene, styrene-butadiene-styrene copolymer, styrene-isoprene-styrene copolymer, and styrene-acrylic acid copolymer; polylactic acid-based resins such as poly-L-lactic acid, poly-D-lactic acid, and poly-DL-lactic acid; polyolefin-based resins such as polyethylene, polypropylene, and saponified ethylene-vinyl acetate copolymer; polyvinyl chloride-based resins such as polyvinyl chloride; and polyvinylidene chloride-based resins such as polyvinylidene chloride. The thermoplastic resins may be used alone or in combination of two or more.

From the viewpoint of excellent handling properties, the thermoplastic resin is preferably at least one selected from the group consisting of polyvinyl chloride resins, polyvinylidene chloride resins, and polyolefin resins, and more preferably at least one selected from the group consisting of polyvinyl chloride resins, polyvinylidene chloride resins, and polyethylene resins.

The polyvinyl chloride resin is preferably a polyvinyl chloride resin with an average degree of polymerization of 700 to 1300, from the viewpoint of excellent formability, heat resistance, and flowability of the wrap film. In this specification, the average degree of polymerization means the average degree of polymerization measured in accordance with JIS K6720-2.

The polyvinyl chloride resin may be a vinyl chloride homopolymer (polyvinyl chloride resin) from the viewpoint of excellent mechanical properties, or may be a copolymer of vinyl chloride and other monomers copolymerizable therewith for the purpose of imparting other properties. The copolymer may be a graft copolymer, a block copolymer, or a random copolymer. Examples of other monomers include olefins such as ethylene, propylene, and butene; vinyl esters of saturated acids such as vinyl acetate and vinyl laurate; alkyl esters of unsaturated acids such as methyl acrylate and methyl methacrylate; alkyl vinyl ethers such as lauryl vinyl ether; aromatic vinyl compounds such as styrene and methylstyrene; unsaturated dicarboxylic acids such as maleic acid; acrylonitrile; and vinylidene fluoride.

When the polyvinyl chloride resin is a copolymer, the content of vinyl chloride units in the copolymer may be 10% by mass or more based on the total amount of monomer units, and from the viewpoint of excellent mechanical properties, is preferably 30% by mass or more, more preferably 50% by mass or more. The upper limit of the content of vinyl chloride units in the copolymer is not particularly limited, and may be, for example, 99% by mass or less based on the total amount of monomer units.

The polyvinyl chloride resin may be, for example, a polymer blend with a three-dimensional polymer such as acrylonitrile-butadiene-styrene, a product post-treated with alcohol, or a product post-treated with a chlorine-containing compound. In these cases, the content of vinyl chloride units in the polyvinyl chloride resin may be 10 mass% or more based on the total amount of monomer units.

The polyvinylidene chloride resin may be a vinylidene chloride homopolymer (polyvinylidene chloride resin), or may be, for example, a copolymer containing vinylidene chloride and other monomers copolymerizable with vinylidene chloride as monomer units. The other monomers may be vinyl chloride, acrylic acid esters of acrylic acid and alcohols having 1 to 8 carbon atoms, methacrylic acid esters of methacrylic acid and alcohols having 1 to 8 carbon atoms, vinyl esters of aliphatic carboxylic acids, unsaturated aliphatic carboxylic acids, olefins, vinyl ethers, and the like. Note that copolymers of vinylidene chloride and vinyl chloride belong to the category of polyvinylidene chloride resins.

From the viewpoint of formability and heat resistance of the wrap film, the content of vinylidene chloride units in the polyvinylidene chloride resin may be, for example, 60% by mass or more, 70% by mass or more, or 80% by mass or more based on the total amount of monomer units. The upper limit of the content of vinylidene chloride units in the polyvinylidene chloride resin is not particularly limited, and may be, for example, 99% by mass or less based on the total amount of monomer units. The content of vinylidene chloride units can be measured by a nuclear magnetic resonance (NMR) device.

The weight average molecular weight (Mw) of the polyvinylidene chloride resin may be, for example, 40,000 or more, 60,000 or more, or 80,000 or more, and may be 180,000 or less, 160,000 or less, or 140,000 or less, or may be 40,000 to 180,000, 60,000 to 160,000, or 80,000 to 140,000. The Mw of the polyvinylidene chloride resin can be measured by the GPC method using polystyrene of known molecular weight as a standard substance.

The conditions of the GPC method used for measuring the Mw of the polyvinylidene chloride resin are as follows: A gel chromatograph Alliance GPC2000 manufactured by Waters Corporation is used as the measuring device. A polyvinylidene chloride resin dissolved in tetrahydrofuran to a concentration of 0.5% by mass is used as a sample.
Column: Tosoh Corporation TSKgel GMHHR-H(S)HT 30 cm x 2, TSKgel GMH6-HTL 30 cm x 2
Mobile phase: tetrahydrofuran Detector: differential refractometer Flow rate: 1.0 mL/min Column temperature: 20° C.
Injection volume: 500 μL

The polyolefin resin may be, for example, a polyethylene resin. The polyethylene resin may be a copolymer having low density polyethylene, linear low density polyethylene, linear very low density polyethylene, medium density polyethylene, high density polyethylene, or ethylene as a monomer unit. Specifically, the polyethylene resin may be a copolymer of ethylene and one or more monomers selected from α-olefins having 3 to 10 carbon atoms such as propylene, 1-butene, 1-pentene, 1-hexene, 4-methyl-1-pentene, 1-heptene, and 1-octene, vinyl esters such as vinyl acetate and vinyl propionate, unsaturated carboxylic acid esters such as methyl acrylate, ethyl acrylate, methyl methacrylate, and ethyl methacrylate, and unsaturated compounds such as conjugated dienes and non-conjugated dienes. The content of ethylene units in the polyethylene resin may be 50% by mass or more based on the total amount of monomer units.

From the viewpoint of excellent productivity, the content of the thermoplastic resin may be 60% by mass or more, 70% by mass or more, or 73% by mass or more based on the total amount of the wrap film, and may be 90% by mass or less, 85% by mass or less, or 80% by mass or less.

(Antiviral agents containing silver and copper)
The antiviral agent containing silver and copper (hereinafter also referred to as "silver- and copper-based antiviral agent") includes an antibacterial agent containing silver and copper having antiviral properties. The silver- and copper-based antiviral agent may or may not further contain a metal other than silver and copper.

The silver and copper-based antiviral agent is an antiviral agent containing metallic silver, silver ions or a silver compound, and metallic copper, copper ions or a copper compound. The silver and copper-based antiviral agent may be, for example, an antiviral agent in which at least one selected from the group consisting of metallic silver, silver ions and silver compounds (e.g., silver complex salts) and at least one selected from the group consisting of metallic copper, copper ions and copper compounds (e.g., copper complex salts) are supported on a carrier such as an inorganic compound. The silver and copper-based antiviral agent may be an antiviral agent in which metallic silver, silver ions or a silver compound (e.g., silver complex salts) and metallic copper, copper ions or a copper compound (e.g., copper complex salts) are supported on a carrier (e.g., an inorganic compound) having a porous structure. Examples of such silver and copper-based antiviral agents include zeolite-silver and copper-based antiviral agents, glass-silver and copper-based antiviral agents, calcium phosphate-silver and copper-based antiviral agents, zirconium phosphate-silver and copper-based antiviral agents, and silicate-silver and copper-based antiviral agents.

Zeolite-silver and copper-based antiviral agents can be obtained, for example, by adding an aqueous silver nitrate solution and an aqueous copper nitrate solution to an aqueous suspension of synthetic zeolite type A, substituting a certain amount of silver ions and copper ions for the Na positions in the crystal structure through an ion exchange reaction, drying, and then calcining. Zeolite-silver and copper-based antiviral agents are available, for example, as "Zeomic AC10D" manufactured by Sinanen Zeomic Co., Ltd.

Glass-silver and copper-based antiviral agents can be obtained, for example, by supporting silver and copper on silicate glass.

Calcium phosphate-silver and copper-based antiviral agents can be obtained, for example, by mixing an aqueous suspension of calcium phosphate, hydroxyapatite, calcium silicate, etc. with a silver nitrate solution and an aqueous copper nitrate solution, and allowing metallic silver or silver ions and metallic copper or copper ions to be supported on the calcium phosphate.

Zirconium phosphate-silver and copper-based antiviral agents can be obtained, for example, by substituting protons for lithium in crystalline lithium zirconium phosphate obtained by hydrothermal synthesis through acid treatment, further substituting the protons for silver ions and copper ions, and then drying and calcining the product.

Silicate-silver and copper-based antiviral agents can be obtained, for example, by loading silver ions and copper ions onto magnesium aluminometasilicate, followed by drying and calcination.

The silver and copper-based antiviral agent may be in particulate form. The average particle size of the particulate silver and copper-based antiviral agent may be, for example, 0.1 μm or more, 0.2 μm or more, or 0.5 μm or more, and may be 2 μm or less, 1.5 μm or less, or 1.2 μm or less.

The content of the silver and copper-based antiviral agent is 0.25% by mass or more and 0.95% by mass or less based on the total amount of the wrap film. When the content of the silver and copper-based antiviral agent is 0.25% by mass or more, excellent antiviral properties are obtained. When the content of the silver and copper-based antiviral agent is 0.95% by mass or less, the film adhesion, film formability and transparency are improved. According to conventional knowledge, it was expected that the more the amount of additives having antiviral effects is, the better the antiviral properties will be, but the inventors have discovered that when the content of the silver and copper-based antiviral agent exceeds 0.95% by mass, the antiviral properties (especially against influenza A virus) are deteriorated, and when the content is 0.95% by mass or less, excellent antiviral properties against both influenza A virus and feline calicivirus are obtained. In addition, if the content of the silver and copper-based antiviral agent is 0.95% by mass or less, the antiviral agent can be uniformly dispersed in the film without using a dispersant, so costs can be reduced. However, this does not prohibit the use of dispersants.

From the viewpoint of further improving the antiviral properties, the content of the silver and copper-based antiviral agent may be 0.3 mass% or more, 0.35 mass% or more, 0.4 mass% or more, 0.45 mass% or more, or 0.5 mass% or more, based on the total amount of the wrap film. From the viewpoint of further achieving excellent antiviral properties and improved film adhesion, film formability, and transparency at the same time, the content of the silver and copper-based antiviral agent may be 0.9 mass% or less, 0.85 mass% or less, 0.8 mass% or less, 0.75 mass% or less, or 0.7 mass% or less, based on the total amount of the wrap film.

(Plasticizer)
The wrap film may further contain a plasticizer, which may be, for example, an adipic acid ester, an epoxidized vegetable oil, or the like.

The adipate ester may be, for example, a diester (adipic acid diester) of adipic acid and a linear or branched aliphatic alcohol having 6 to 10 carbon atoms. The adipate ester may be, for example, dioctyl adipate, diisononyl adipate, etc.

The epoxidized vegetable oil may be, for example, epoxidized soybean oil, epoxidized linseed oil, epoxidized castor oil, epoxidized corn oil, epoxidized rapeseed oil, epoxidized safflower oil, epoxidized sunflower oil, epoxidized palm oil, epoxidized cottonseed oil, epoxidized olive oil, etc.

The plasticizer content may be, for example, 10% by mass or more, 15% by mass or more, or 20% by mass or more, and 30% by mass or less, 27% by mass or less, or 25% by mass or less, based on the total amount of the wrap film. When the plasticizer content is within these ranges, the plasticity of the wrap film is appropriately improved, making it easier for the silver- and copper-based antiviral agents to be uniformly incorporated into the wrap film, and excellent film-forming properties are obtained. In addition, when the plasticizer content is within the above ranges, the silver- and copper-based antiviral agents are less likely to be exposed on the surface of the wrap film, making it less likely for unevenness to form, and therefore good adhesive strength can be obtained.

(Glycerin-based anti-fogging agent)
The wrap film may further contain a glycerin-based anti-fogging agent. In order to obtain excellent transparency, the glycerin-based anti-fogging agent may contain a polyglycerin fatty acid ester having an ester structure derived from glycerin and a fatty acid having 8 to 22 carbon atoms. When the fatty acid constituting the polyglycerin fatty acid ester has a carbon number of 8 to 22, the antiviral properties of the wrap film are further improved. The carbon number of the fatty acid may be 10 or more or 12 or more, or 20 or less or 18 or less.

The fatty acid may be a saturated fatty acid or an unsaturated fatty acid. Examples of saturated fatty acids include caprylic acid, pelargonic acid, capric acid, lauric acid, myristic acid, palmitic acid, and stearic acid. Examples of unsaturated fatty acids include monounsaturated fatty acids such as myristoleic acid, palmitic acid, sapienic acid, oleic acid, and eicosenoic acid; diunsaturated fatty acids such as linoleic acid, eicosadienoic acid, and docosadienoic acid; triunsaturated fatty acids such as α-linolenic acid, γ-linolenic acid, and pinolenic acid; and tetraunsaturated fatty acids such as arachidonic acid.

式（１）中、Ｒは、炭素数７～２１の１価の脂肪族炭化水素基を示し、ｎは１～４の数を示す。 The glycerin-based antifogging agent may contain a polyglycerin fatty acid ester represented by the following formula (1) in order to obtain excellent transparency.

In formula (1), R represents a monovalent aliphatic hydrocarbon group having 7 to 21 carbon atoms, and n represents a number from 1 to 4.

When the glycerin-based anti-fogging agent contains a polyglycerin fatty acid ester represented by formula (1), the antiviral properties of the wrap film are further improved. The aliphatic hydrocarbon group is a residue obtained by removing a carboxyl group from the above-mentioned fatty acid. The number of carbon atoms in the aliphatic hydrocarbon group may be 9 or more or 11 or more, and may be 19 or less or 17 or less. R may be a saturated aliphatic hydrocarbon group having 7 to 13 carbon atoms, or an unsaturated aliphatic hydrocarbon group having 8 to 21 carbon atoms.

Examples of polyglycerol fatty acid esters include diglycerol fatty acid esters such as diglycerol monocaprylate, diglycerol monocaprate, diglycerol monolaurate, diglycerol monomyristate, diglycerol monomyristate, diglycerol monopalmitate, diglycerol monostearate, diglycerol monooleate, diglycerol monolinoleate, and diglycerol monoercate; triglycerol monocaprylate, triglycerol monocaprate, triglycerol monolaurate, triglycerol monomyristate, triglycerol monooleate, triglycerol monolinoleate, and triglycerol monoercate; triglycerol fatty acid esters such as tetraglycerol monocaprylate, tetraglycerol monocaprate, tetraglycerol monolaurate, tetraglycerol monomyristate, tetraglycerol monooleate, tetraglycerol monolinoleate, tetraglycerol monoerucate, and other tetraglycerol fatty acid esters; pentaglycerol fatty acid esters such as pentaglycerol monocaprylate, pentaglycerol monocaprate, pentaglycerol monolaurate, pentaglycerol monomyristate, pentaglycerol monooleate, pentaglycerol monolinoleate, and pentaglycerol monoerucate.

The polyglycerol fatty acid ester may contain at least one selected from diglycerol monolaurate, triglycerol monolaurate, tetraglycerol monolaurate, and pentaglycerol monolaurate, in order to further improve the antiviral properties of the wrap film.

The content of polyglycerol fatty acid ester may be 0.1% by mass or more, 0.2% by mass or more, or 0.3% by mass or more based on the total amount of the wrap film, from the viewpoint of further improving the antiviral properties of the wrap film, and may be 2.0% by mass or less, 1.5% by mass or less, or 1.0% by mass or less, from the viewpoint of further improving the transparency of the wrap film.

The glycerin-based anti-fogging agent may further include a monoglycerin fatty acid ester or a sorbitan fatty acid ester. Examples of the monoglycerin fatty acid ester include monoglycerin laurate, monoglycerin myristate, monoglycerin palmitate, monoglycerin stearate, monoglycerin oleate, and monoglycerin linoleate. Examples of the sorbitan fatty acid ester include sorbitan laurate and sorbitan stearate.

The total amount of the glycerin-based anti-fogging agent may be 0.1% by mass or more, 0.3% by mass or more, or 0.5% by mass or more based on the total amount of the wrap film from the viewpoint of the adhesiveness of the wrap film, and may be 2.5% by mass or less, 2.0% by mass or less, or 1.5% by mass or less from the viewpoint of the dimensional stability and drawability of the wrap film.

(Stabilizer)
The wrap film may further contain a stabilizer (heat stabilizer or light stabilizer). The stabilizer may be, for example, a Ca/Zn stabilizer. The Ca/Zn stabilizer is a mixture of a fatty acid salt of calcium and a fatty acid salt of zinc. Examples of the fatty acid include behenic acid, stearic acid, lauric acid, oleic acid, palmitic acid, and ricinoleic acid.

The stabilizer content may be, for example, 0.1% by mass or more or 0.5% by mass or more, and 5% by mass or less or 3% by mass or less, based on the total amount of the wrap film.

(Other ingredients)
The wrap film may further contain other components in addition to the glycerin-based anti-fog agent, plasticizer, and stabilizer (heat stabilizer or light stabilizer). Examples of other components include colorants, lubricants, fillers, plate-out inhibitors, antioxidants, release agents, viscosity reducers, surfactants, fluorescent agents, surface treatment agents, crosslinking agents, processing aids, adhesives, antistatic agents, ultraviolet absorbers, and antiblocking agents. When the wrap film contains other components, the content (total content) of the other components may be, for example, 1% by mass or more and 30% by mass or less based on the total amount of the wrap film.

Examples of colorants include blue colorants such as copper phthalocyanine (copper phthalocyanine blue) and iron(III) hexacyanoferrate (II), red colorants such as quinacridone red, yellow colorants such as a mixture of o-nitroaniline and acetoacetanilide, and a mixture of 4-chloro-2-nitroaniline and acetoacetanilide, green colorants such as α-nitroso-β-naphthol iron complex, and purple colorants such as quinacridone violet. The colorant may contain at least one selected from the group consisting of these colorants.

The wrap film may consist of only one layer containing the thermoplastic resin and the silver- and copper-based antiviral agent, or may consist of multiple layers. When the wrap film consists of multiple layers, the thermoplastic resin and the silver- and copper-based antiviral agent may be contained in any of the layers, may be contained in the same layer, or may be contained in different layers.

When the wrap film is made of multiple layers, the wrap film may, for example, have a first surface layer, an intermediate layer, and a second surface layer in this order. In this case, for example, the first and second surface layers may contain a thermoplastic resin, a silver- and copper-based antiviral agent, and other components added as needed, and the intermediate layer may contain a thermoplastic resin and other components added as needed. For example, the wrap film may further have an adhesive layer containing an acid-modified polyolefin resin or the like to improve the adhesion between the layers, and may further have a heat-resistant layer containing a polyamide-based resin to improve the heat resistance of the wrap film.

From the viewpoints of workability and strength, the thickness of the wrap film may be preferably 10 μm or less, more preferably 9 μm or less, and even more preferably 8 μm or less, and from the viewpoint of efficiently insulating food from the outside air, the thickness may be preferably 4 μm or more, more preferably 5 μm or more, and even more preferably 6 μm or more.

From the viewpoint of excellent visibility, the total light transmittance of the wrap film is preferably 75% or more, more preferably 80% or more, and may be, for example, 90% or less. The total light transmittance can be calculated by measuring the amount of incident light and the total amount of transmitted light in accordance with JIS K7361-1, and calculating the total light transmittance = (total amount of transmitted light) / (amount of incident light) x 100.

The wrap film can be manufactured, for example, as follows. First, the thermoplastic resin and the silver- and copper-based antiviral agent are mixed with the above-mentioned colorant and other components as necessary using a mixer such as a V-type blender, ribbon blender, Henschel mixer, or super mixer. Next, the resulting mixture is kneaded as necessary using a kneader such as a mixing roll, Banbury mixer, or kneader to obtain a composition. The resulting composition is then extruded, for example, to obtain a wrap film. More specifically, the composition is fed into the hopper of an extruder, and the desired wrap film is obtained using an inflation method, T-die method, or the like.

When the wrap film is made up of multiple layers, the wrap film is obtained by feeding the constituent materials of each layer into separate extruders, melt extruding them, and then co-extruding and laminating the layers using an inflation method, T-die method, or the like. In this case, it is preferable to form the wrap film by taking up the molten material extruded from the T-die as it is while rapidly cooling it with a casting roll, or the like.

The wrap film thus obtained may be subjected to heat treatments such as longitudinal stretching between heated rolls, various types of heat fixing, and aging, depending on the purpose of reducing the thermal shrinkage rate and natural shrinkage rate, and suppressing the occurrence of width shrinkage. To improve anti-fogging properties, anti-static properties, adhesion, etc., corona treatment, aging treatment, surface treatments such as printing and coating, surface finishing, etc. may also be performed.

[Wrap film container]
The wrap film is, for example, formed into a long shape and wound up, and then rewound (rolled) at desired lengths of 20 m, 50 m, etc., and packed into a box to form a product. That is, the wrap film in this embodiment may be in the form of a wrap film wound around a core, or in the form of a wrap film contained in a box.

Figure 1 is a perspective view showing a wrap film container according to one embodiment. As shown in Figure 1, the wrap film container 1 according to one embodiment includes a wrap film 2, a core 3 around which the wrap film is wound, and a box 4 that contains the wrap film 2 and the core 3. The box 4 may be provided with a blade 5 for cutting the wrap film 2. The material of the core 3 and the box 4 is not particularly limited. From the viewpoint of making it easy to recognize the color of the wrap film from the outside, at least a part of the box 4 is preferably transparent or has a hole therein to the extent that the function as a box is not impaired, so that the inside can be seen from the outside.

In general, a "film" refers to a thin, flat product that is extremely thin compared to its length and width, has an arbitrarily limited maximum thickness, and can be supplied in roll form (Japanese Industrial Standard JIS K6900 can be referenced if necessary), and a "sheet" generally refers to a thin, flat product, as defined in JIS, whose thickness is generally small compared to its length and width. However, the boundary between a sheet and a film is unclear, and since there is no need to distinguish between the two in the wording of this embodiment, in this specification, the term "film" is intended to include "sheet," and the term "sheet" is intended to include "film." Furthermore, "film" is a concept that includes wrap film in particular, among the above definitions.

The present invention will be described in more detail below with reference to examples, but the present invention is not limited to these examples.

(1) Preparation of resin composition The following materials were charged into a super mixer in the amounts (% by mass) shown in Table 1, and then the material temperature was raised from room temperature to 130°C while stirring, and the materials were mixed to prepare resin compositions of the examples and comparative examples.
Thermoplastic resin: polyvinyl chloride resin Silver and copper-based antiviral agent: Zeolite-silver and copper-based antibacterial and antiviral agent (manufactured by Sinanen Zeomic Co., Ltd., "Zeomic AC10D")
Silver-containing additive: zirconium phosphate-silver antibacterial agent (manufactured by Toagosei Co., Ltd., "Novalon AG300")
Plasticizer 1: Diisononyl adipate Plasticizer 2: Epoxidized soybean oil Glycerin-based anti-fog agent 1: Glycerin monooleate (manufactured by Riken Vitamin Co., Ltd., "XO-100")
Glycerin-based anti-fogging agent 2: Diglycerin monolaurate (manufactured by Riken Vitamin Co., Ltd., "Poem DL-100")
Stabilizer: Ca/Zn stabilizer

(2) Preparation of wrap film The resin composition cooled to 70°C was extruded using a 40 mm diameter single screw extruder (L/D = 20) equipped with a T-die (width 350 mm, gap 0.4 mm) at a temperature of 200°C to prepare a wrap film having a thickness of 8.0 µm.

(3) Evaluation The evaluation results of the resin compositions and wrap films in each of the Examples and Comparative Examples are shown in Table 1.

(Adhesive strength to film)
The adhesion to the film was evaluated using a Strograph (Toyo Seiki Seisakusho, E3-L). The film was spread without wrinkles on a stainless steel plate of 18 cm length and 25 cm width, and a weight was applied with a roller, and then the film was attached along the stainless steel plate. On top of the film cut along the stainless steel plate, another film was cut along the stainless steel plate, and the two films were attached to each other by applying a weight with a roller in the same manner as above. The sample with the films attached to each other was attached to a Strograph, and the film adhesion was measured by peeling at an angle of 180 degrees at 500 mm/min in an indoor environment of 23±2°C temperature and 55±15% humidity. The above measurement was repeated three times, and the average value was taken as the actual measurement value.
A: The adhesive strength to the film was 6.0 cN or more.
B: The adhesive strength to the film was less than 6.0 cN.

(Film-forming ability)
The above-mentioned resin composition was extruded at 200° C. using a T-die extruder to form a wrap film, and the appearance of the obtained wrap film was observed to evaluate the film formability. The evaluation criteria were as follows.
A: A wrap film of almost uniform thickness was obtained, and no discoloration occurred after 24 hours of extrusion.
B: The wrap film had slight unevenness in thickness, and discoloration occurred after 24 hours of extrusion.

(transparency)
The transparency was evaluated by measuring the haze (cloudiness) of the wrap film using a haze meter (manufactured by Nippon Denshoku Industries Co., Ltd., NDH 5000). After standard calibration was performed using a standard plate for NDH-5000 (cloudiness 11.35, H51-28491), the wrap film was attached to a cloudiness tool without wrinkles and the haze was measured. The same measurement was performed three times at different measurement locations on the wrap film, and the average haze value was calculated.
A: The average haze of the wrap film was 4.0 or less.
B: The average haze of the wrap film was more than 4.0.

(Antiviral activity against influenza A virus)
The antiviral property was evaluated using influenza A virus in accordance with ISO 21702. The virus infectivity of the wrap film was measured to calculate the antiviral activity value.
A: The antiviral activity value of the wrap film was 2.0 or higher.
B: The antiviral activity value of the wrap film was less than 2.0.

(Antiviral activity against feline calicivirus)
The antiviral property was evaluated using feline calicivirus in accordance with ISO 21702. The virus infectivity of the wrap film was measured to calculate the antiviral activity value.
A: The antiviral activity value of the wrap film was 2.0 or higher.
B: The antiviral activity value of the wrap film was less than 2.0.

As shown in the table below, the films of Examples 1 and 2 had an antiviral rating of A against both influenza A virus and feline calicivirus, and thus had excellent antiviral properties. On the other hand, the films of Comparative Examples 1 to 3 had an antiviral rating of B against at least one of influenza A virus and feline calicivirus, and thus did not have good antiviral properties.

1...wrap film container, 2...wrap film, 3...core, 4...box body, 5...blade portion.

Claims (6)

A wrap film containing a thermoplastic resin and an antiviral agent containing silver and copper,
A wrap film having an antiviral agent content of 0.25% by mass or more and 0.95% by mass or less, based on the total amount of the wrap film. The wrap film according to claim 1, wherein the thermoplastic resin comprises at least one selected from the group consisting of polyolefin-based resins, polyvinyl chloride-based resins, and polyvinylidene chloride-based resins. The wrap film according to claim 1, further comprising a plasticizer, the content of the plasticizer being 10% by mass or more and 30% by mass or less based on the total amount of the wrap film. The wrap film according to claim 1, further comprising a glycerin-based anti-fogging agent. The wrap film according to claim 1, which is used for packaging food. A core;
The wrap film according to any one of claims 1 to 5, which is wound around the core;
A wrap film container comprising: a box body that contains the core and the wrap film.

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