JP2023143684A - Film for food packaging, and small-wound film for food packaging - Google Patents

Abstract

To provide a film for food packaging which achieves both adhesion to an adherend and high antibacterial property.SOLUTION: A film for food packaging has a layer (I) formed of a resin composition containing a thermoplastic resin and an inorganic antibacterial agent on at least one of the front and rear surfaces of the film, wherein the content of the inorganic antibacterial agent in the resin composition is 0.02-5 mass%.SELECTED DRAWING: None

Description

The present invention relates to a food packaging film. More specifically, it is a plastic film for chlorine and polyvinyl chloride that has high antibacterial properties and excellent adhesion to adherends such as containers, and can be suitably used as a food packaging film with excellent food safety and a small roll film for food packaging. This invention relates to a food packaging film that does not contain any additives.

Food packaging films are used to package cooked foods on ceramic or plastic containers. Conventionally, food packaging films (also referred to as food packaging wrap films or simply wrap films) used in general households or in the food service industry such as hotels and restaurants have mainly been made of polyvinylidene chloride resin or polyvinyl chloride resin. It has been used as a raw material. This is due to the cutting performance when cutting to a specified length with a saw blade when stored in a carton box with a cutter blade, the stickiness when covering an object such as a container, and the durability when heating in a microwave oven. This is because the film has excellent practical heat resistance without melting, so it has an advantage in terms of quality in food packaging and related usage environments.

In recent years, attempts have been made to impart antibacterial properties to food packaging films to inhibit food spoilage bacteria, extend the best-before date or expiration date, and reduce food loss. Furthermore, imparting antibacterial properties to food packaging films is expected to have the effect of preventing food poisoning in addition to reducing food loss, and is an important element in giving consumers a sense of security.

For example, Patent Documents 1 and 2 propose a laminated antibacterial film for vacuum packaging applications in which an antibacterial agent is incorporated into a sealant layer, which is the innermost layer in contact with food.

Further, Patent Document 3 proposes a wrap film having antibacterial properties that is made of a thermoplastic resin, a colorant, and a silver-based antibacterial agent.

Japanese Patent Application Publication No. 2015-189138 JP 2016-30406 Publication International Publication No. 2020/027188

However, since the films described in Patent Document 1 and Patent Document 2 are for vacuum packaging, they do not have sufficient adhesion when covering an adherend such as a container, which is important as a wrap film, and cannot be used as a wrap film. The problem is that it is inappropriate.

Furthermore, the wrap film having antibacterial properties described in Patent Document 3 mainly describes a single layer structure, so there was a problem that it could not be realized because there was no detailed explanation of the structure or technology for making it into a laminated film. In fact, the present inventors attempted to impart antibacterial properties by adding an antibacterial agent to a laminated wrap film, but increasing the amount of antibacterial agent to develop antibacterial properties resulted in loss of adhesion. On the other hand, there is a problem in that if the amount of antibacterial agent added is reduced in order to achieve the required adhesiveness, the antibacterial properties will be impaired.

The present invention has been made in view of the above problems, and provides a food packaging film that has both adhesion to adherends and high antibacterial properties.

In order to solve the above-mentioned problems, the present inventors have made extensive studies and found that a layer consisting of a resin composition containing a thermoplastic resin and a specific amount of an inorganic antibacterial agent is provided on at least one of the front and back surfaces of the film. The present inventors have discovered that good antibacterial properties and sufficient adhesiveness can be obtained as a film for food packaging by creating a film having the above properties, and have completed the present invention.

That is, the gist of the present invention is as follows.
[1] A food packaging film having a layer (I) made of a resin composition containing a thermoplastic resin and an inorganic antibacterial agent on at least one of the front and back surfaces of the film, wherein the inorganic antibacterial agent in the resin composition is A food packaging film having an antibacterial agent content of 0.02 to 5% by mass.
[2] The inorganic antibacterial agent is an inorganic compound in which metal ions are supported on an inorganic carrier, and the metal species of the metal ions is at least one selected from the group consisting of silver, copper, and zinc. The food packaging film according to [1], wherein the inorganic support is at least one selected from the group consisting of zeolite, zirconium phosphate, and glass.
[3] The food packaging film according to [2], wherein the content of metal ions in the inorganic antibacterial agent is 0.01 to 20% by mass based on the total mass of the inorganic antibacterial agent.
[4] The food packaging film according to any one of [1] to [3], wherein the layer (I) has a thickness of 0.1 to 10 μm.
[5] The food packaging film according to any one of [1] to [4], wherein the thermoplastic resin is a polyolefin resin.
[6] The food packaging film according to any one of [1] to [5], wherein the adhesive force between the layer (I) and the glass is 50 mN or more.
[7] The food packaging film according to any one of [1] to [6], which has a thickness of 30 μm or less.
[8] The food packaging film according to any one of [1] to [7], wherein the inorganic antibacterial agent has an average particle size of 3 μm or less.
[9] The resin composition further includes an antifogging agent, and the content of the antifogging agent in the resin composition is 0.1 to 12% by mass, according to any one of [1] to [8]. food packaging film.
[10] The food packaging film according to any one of [1] to [9], wherein the food packaging film has a functional layer.
[11] The food packaging film according to any one of [1] to [10], wherein the functional layer is a layer made of a resin composition containing a polyamide resin as a main component.
[12] A small roll film for food packaging, comprising the food packaging film according to any one of [1] to [11].
[13] The small roll film for food packaging according to [12], which is housed in a carton box.

According to the present invention, the film of the present invention can provide a food packaging film that exhibits good adhesion to adherends and has high antibacterial properties. Furthermore, since it has high antibacterial properties even with a lower content of antibacterial agent than the conventional technology, it is superior in terms of economy.

It is a figure showing an example of a carton box with a cutter blade.

Hereinafter, a food packaging film (hereinafter referred to as "this film") as an example of an embodiment of the present invention will be described. However, the scope of the present invention is not limited to the embodiments described below.

In the present invention, the term "main component" includes the meaning that other components may be included as long as they do not interfere with the function of the main component, unless otherwise specified. In this case, the content ratio of the main component is not specified, but the main component (if two or more components are the main components, the total amount of these components) is 50% by mass or more, especially 70% by mass in the composition. % or more, especially preferably 90% by mass or more (including 100% by mass).

In addition, in the present invention, when expressed as "X to Y" (X, Y are arbitrary numbers), unless otherwise specified, it means "more than or equal to X and less than or equal to Y", and also means "preferably greater than X" and "preferably is less than Y. In addition, in the present invention, when expressed as "more than or equal to X" (X is any number), unless otherwise specified, it includes the meaning of "preferably greater than X" and "less than or equal to Y" (where Y is any number). ) includes the meaning of "preferably smaller than Y" unless otherwise specified.

In this specification, the term "monomer component" refers to a repeating unit incorporated into the resin derived from a monomer that is a raw material for producing the resin, and is also referred to as a "structural unit" or "unit."
Moreover, the above-mentioned "ethylene unit" refers to a repeating unit incorporated into the resin derived from ethylene, which is a raw material for manufacturing the resin. The same applies to "vinyl acetate units" and "propylene units."
Furthermore, in this specification, "(meth)acrylic acid" represents one or both of "acrylic acid" and "methacrylic acid."

Additionally, in general, a "sheet" refers to a flat product that is thin and generally has a small thickness compared to its length and width, and a "film" generally refers to a flat product that is thin compared to its length and width. A thin, flat product with an extremely small thickness and an arbitrarily limited maximum thickness, usually supplied in the form of a roll (Japanese Industrial Standard JIS K6900). For example, in terms of thickness, in a narrow sense, a thickness of 100 μm or more is sometimes referred to as a sheet, and a thickness of less than 100 μm is sometimes referred to as a film. However, the boundary between a sheet and a film is unclear, and there is no need to distinguish between the two in terms of the wording in the present invention. Therefore, in the present invention, even when the term ``film'' is used, the term ``sheet'' is included, and the term ``sheet'' is used. "film" shall be included even if

This film has a layer (I) made of a resin composition containing a thermoplastic resin and an inorganic antibacterial agent on at least one of the front and back surfaces of the film. That is, the present film is a multilayer film composed of at least two layers including layer (I). Each component contained in the resin composition constituting layer (I) will be explained below.

<Layer (I)>
〔Thermoplastic resin〕
The thermoplastic resin is not particularly limited as long as it is a thermoplastic resin used for food packaging, and examples thereof include polyolefin resins, polystyrene resins, polyester resins, and the like. These may be used alone or in combination of two or more. Among these, polyolefin resins are preferred from the viewpoint of adhesiveness.

Examples of the polyolefin resin include homopolymerized α-olefins such as ethylene, propylene, 1-butene, 1-pentene, 1-hexene, 1-heptene, 1-octene, 1-nonene, or 1-decene. Examples include polymers and copolymers containing α-olefin as the main monomer component. Among these, polyethylene resins containing ethylene as the main monomer component and polypropylene resins containing propylene as the main monomer component are preferred from the viewpoint of adhesiveness, transparency, etc., and polyethylene resins are particularly preferred. Here, the main monomer component refers to a monomer component that accounts for 50% by mass or more and 100% by mass or less in the resin.

The polyethylene resin is not particularly limited as long as it is a resin containing ethylene as a main monomer component, and examples include low density polyethylene, linear low density polyethylene, linear very low density polyethylene, medium density polyethylene, and high density polyethylene. It will be done.
Further, the polyethylene resin may be an ethylene homopolymer, or a copolymer containing ethylene as a main monomer component and other copolymerizable monomer components.

Examples of the other copolymerizable monomer components (comonomers) include those having 3 to 3 carbon atoms, such as propylene, 1-butene, 1-pentene, 1-hexene, 4-methyl-1-pentene, 1-heptene, and 1-octene. 10 α-olefins, vinyl esters such as vinyl acetate and vinyl propionate, unsaturated carboxylic acid esters such as methyl (meth)acrylate and ethyl (meth)acrylate, and their ionomers, conjugated dienes and non-conjugated dienes. Examples include unsaturated compounds. The proportion of other copolymerizable monomer components is not particularly limited, but is usually 30% by mass or less, more preferably 15% by mass or less. By including other copolymerizable monomer components, flexibility and transparency can be increased in the film.

The copolymer is, for example, a copolymer or multicomponent copolymer containing ethylene as the main monomer component and one or more comonomers selected from the other copolymerizable monomer components, or a multicomponent copolymer thereof. Mixed compositions and the like can be mentioned.

Among the polyethylene resins, low density polyethylene, linear low density polyethylene, linear very low density polyethylene, ethylene-vinyl acetate copolymer (EVA), ethylene-(meth)acrylate copolymer, ionomer resin is preferred, and linear low density polyethylene is particularly preferred.

The linear low density polyethylene may be a linear low density polyethylene containing at least one α-olefin selected from the group consisting of 1-butene, 1-hexene, and 4-methyl-1-pentene as a comonomer. preferable. The proportion of these comonomer components is not particularly limited, but is usually 30% by mass or less, more preferably 15% by mass or less. By including these comonomer components, flexibility and transparency can be improved in the film.

The method for producing the polyethylene resin is not particularly limited, and may be a known polymerization method using a known olefin polymerization catalyst, such as a multisite catalyst such as a Ziegler-Natta catalyst or a metallocene catalyst. Examples include slurry polymerization method, solution polymerization method, bulk polymerization method, gas phase polymerization method, etc. using a single-site catalyst, and bulk polymerization method using a radical initiator.

The melting point of the polyethylene resin is preferably 70 to 130°C, more preferably 80 to 120°C. If the melting point of the polyethylene resin is 70 to 130°C, it tends to improve the tensile strength and dimensional stability of the film.
Here, the melting point is determined using a differential scanning calorimeter (DSC) by heating approximately 10 mg of resin from -50°C to 200°C at a heating rate of 10°C/min, holding it at 200°C for 1 minute, and then cooling at a rate of This is the crystal melting peak temperature (Tm) (°C) determined from the thermogram measured when the temperature was lowered to -50°C at a heating rate of 10°C/min and then raised to 200°C at a heating rate of 10°C/min.

The melt flow rate (MFR) of the polyethylene resin is not particularly limited, but is usually 0.1 g/10 minutes or more, preferably 0.5 to 18 g/10 minutes, and 1 to 15 g/10 minutes. More preferably, it is minutes. If MFR is 0.1 g/10 minutes or more, extrusion processability is stable, and if it is 20 g/10 minutes or less, stable film formation is possible during molding, and there is no problem with uneven thickness, decrease in mechanical strength, or variation. etc., which is preferable.
Here, MFR is a value measured in accordance with JIS K7210-1 (2014), and the measurement conditions are 190° C. and a load of 2.16 kg.

The density of the polyethylene resin is preferably 0.880 to 0.980 g/cm ³ , more preferably 0.890 to 0.960 g/cm ³ , and more preferably 0.900 to 0.940 g/cm ³ It is particularly preferable that It is preferable that the density is in the range of 0.880 to 0.980 g/cm ³ because it provides an excellent balance between transparency, strength, adhesiveness, and flexibility. Here, the density is a value measured in accordance with JIS K7112 (1999).

(Polypropylene resin)
The polypropylene resin is not particularly limited as long as it is a resin containing propylene as the main monomer component, and may be a propylene homopolymer, or a resin containing propylene as the main monomer component and copolymerized with other copolymerizable monomer components. It may be a combination. Further, the polypropylene resin may be used alone, or two or more types having different copolymerizable monomer components, compositions, physical properties, etc. may be used in combination.

Examples of the other copolymerizable monomer components (comonomers) include those having 2 to 2 carbon atoms, such as ethylene, 1-butene, 1-pentene, 1-hexene, 4-methyl-1-pentene, 1-heptene, and 1-octene. 20 α-olefins and dienes such as divinylbenzene, 1,4-cyclohexadiene, dicyclopentadiene, cyclooctadiene, ethylidene norbornene, vinyl acetate, (meth)acrylic acid, (meth)acrylic ester, (meth) Examples include glycidyl acrylate, vinyl alcohol, ethylene glycol, maleic anhydride, styrene, and cyclic olefin. The polypropylene resin may be a multicomponent copolymer containing two or more of the other copolymerizable monomer components described above. When the polypropylene resin has a monomer component other than propylene and ethylene, the monomer component is preferably 1-butene.

Further, the polypropylene resin may be a block copolymer, a random copolymer, or a graft copolymer.

The melting point of the polypropylene resin is preferably 70 to 170°C, more preferably 80 to 160°C. If the melting point is within this range, the film will have a good balance between flexibility, strength, and heat resistance, which is preferable.
Here, the melting point is determined using a differential scanning calorimeter (DSC) by heating approximately 10 mg of resin from -50°C to 200°C at a heating rate of 10°C/min, holding it at 200°C for 1 minute, and then cooling at a rate of This is the crystal melting peak temperature (Tm) (°C) determined from the thermogram measured when the temperature was lowered to -50°C at a heating rate of 10°C/min and then raised to 200°C at a heating rate of 10°C/min.

The melt flow rate (MFR) of the polypropylene resin is not particularly limited, but is usually 0.2 g/10 minutes or more, preferably 0.5 to 18 g/10 minutes, and 1 to 15 g/10 minutes. More preferably, it is minutes. If the MFR is 0.2 g/10 minutes or more, extrusion processability is stable, and if it is 20 g/10 minutes or less, stable film formation is possible during molding, and there is no problem with uneven thickness, decrease in mechanical strength, or variations. etc., which is preferable.
Here, MFR is a value measured in accordance with JIS K7210-1 (2014), and the measurement conditions are 230° C. and a load of 2.16 kg.

[Inorganic antibacterial agent]
Layer (I) in this film needs to contain an inorganic antibacterial agent as an antibacterial substance. The inorganic antibacterial agent used in the present invention is not particularly limited as long as it can be safely used in food packaging films and has antibacterial properties, but may include inorganic compounds in which metal ions are supported on an inorganic carrier. It is preferable that
Here, "the metal ion is supported on the inorganic support" refers to a state in which the metal ion is adsorbed or bonded to the inorganic support by physical adsorption, chemical adsorption, ion exchange, or the like.
The method for supporting metal ions on the inorganic support is not particularly limited, and any known method for supporting the metal ions may be used. Known supporting methods include, for example, physical adsorption methods, chemical adsorption methods, ion exchange reactions, methods of supporting using a binder, and the like.

The metal species of the metal ion is preferably at least one selected from silver, zinc, copper, platinum, and the like. From the viewpoint of availability, economy, and safety, silver ions or zinc ions are preferred. Furthermore, silver ions are particularly preferred in that the effects of metal ions are maintained for a longer period of time.

The inorganic carrier is not particularly limited as long as it can support the metal ions, but examples include glass, clay minerals, talc, zinc calcium phosphate, calcium phosphate, zirconium phosphate, aluminum phosphate, titanium phosphate, and silica. Examples include calcium acid, activated carbon, activated alumina, silica gel, zeolite (aluminosilicate), magnesium aluminate metasilicate, hydroxyapatite, potassium titanate, hydrous bismuth oxide, hydrous zirconium oxide, hydrotalcite, and the like. These may be used alone or in combination of two or more. Among these, the inorganic support is preferably at least one selected from the group consisting of zeolite, zirconium phosphate, and glass.

Examples of the zeolite include natural zeolites such as chabasite, mordenite, erionite, and clinoptilolite, and synthetic zeolites such as A-type zeolite, X-type zeolite, and Y-type zeolite.

Among them, examples of inorganic antibacterial agents include silver-supported zeolite, which is silver ion supported on zeolite, silver-supported zirconium phosphate, which is silver ion supported on zirconium phosphate, silver-supported glass, which is silver supported on glass, and Silver-supported silica gel, in which silver ions are supported on silica gel, is preferred, and silver-supported zirconium phosphate is particularly preferred.

In addition, the inorganic antibacterial agent may have two or more types of metal ions supported on one inorganic support, such as silver/copper-supported zeolite or silver/zinc-supported alumina silicate. The above carriers may be combined or mixed.
Furthermore, one type of inorganic antibacterial agent may be used alone, or two or more types may be used in combination.

The content of metal ions in the inorganic antibacterial agent is preferably 0.01 to 20% by mass, more preferably 0.05 to 10% by mass, and 0.10 to 5% by mass, based on the total mass of the inorganic antibacterial agent. % is more preferred.

[Average particle size]
The average particle size of the inorganic antibacterial agent is not particularly limited, but from the viewpoint of improving dispersibility and appearance when molded into a film, it is preferably 3 μm or less, preferably 0.1 to 3 μm, and 0.2 μm or less. ~2 μm is more preferred, 0.3 to 1.5 μm is even more preferred, and 0.5 to 1.2 μm is particularly preferred.
If the average particle size is 3 μm or less, the inorganic antibacterial agent is moderately exposed from the film surface, and the film tends to maintain its adhesiveness. If the average particle size is 0.1 μm or more, the inorganic antibacterial agent is exposed from the film surface. There is a tendency for antibacterial properties to be more easily exerted due to sufficient exposure.
The above average particle size is the value obtained by measuring the diameter of an inorganic antibacterial agent carrying at least 20 arbitrary metal ions using an electron microscope (or the diameter equivalent to a circle if it is not spherical) and arithmetic averaging them. It is.

[Content of inorganic antibacterial agent]
The content of the inorganic antibacterial agent in the resin composition of this film is 0.02 to 5% by mass in order to sufficiently exhibit the adhesiveness and antibacterial properties of the film. It is preferably 0.03 to 4.5% by mass, more preferably 0.04 to 4% by mass, even more preferably 0.05 to 3.5% by mass, particularly preferably 0.08 to 3% by mass. Mass%.

In addition, the content of the inorganic antibacterial agent contained in the entire film is usually 0.01 to 3% by mass, preferably 0.02 to 1.5% by mass, from the viewpoint of achieving both economic efficiency and performance. More preferably 0.025 to 1% by mass.

[Other ingredients]
Various additives may be appropriately blended into the resin composition in order to impart properties such as antibacterial properties, antifogging properties, antistatic properties, slipperiness, and adhesiveness. These may be used alone or in combination of two or more.
For example, in order to impart antifogging properties, an antifogging agent can be blended into the resin composition. By incorporating an antifogging agent, it becomes easier to prevent the surface of the film from becoming cloudy due to dew condensation when it is made into a film, and especially when used as a food packaging film, it becomes easier to prevent the packaged object from becoming difficult to see. Useful.

As the antifogging agent, for example, an aliphatic alcohol fatty acid ester which is a compound of a fatty acid alcohol having 1 to 12 carbon atoms, preferably 1 to 6 carbon atoms, and a fatty acid having 10 to 22 carbon atoms, preferably 12 to 18 carbon atoms. , polyalkyl ether polyols, paraffin oils, and the like. These various antifogging agents may be used alone or in combination of two or more.

Examples of the aliphatic alcohol fatty acid esters include monoglyceriolate, diglycerol oleate, polyglycerol oleate, glycerin triricinolate, glycerin acetyl ricinoleate, polyglycerin stearate, glycerin laurate, polyglycerin laurate, and methyl acetyl ricinoleate. Nolate, ethylacetyl ricinolate, butylacetyl ricinoleate, propylene glycol oleate, propylene glycol laurate, pentaerythritol oleate, polyethylene glycol oleate, polypropylene glycol oleate, sorbitan oleate, sorbitan laurate, polyethylene glycol sorbitan oleate, polyethylene glycol sorbitan laurate etc.
Examples of the polyalkyl ether polyol include polyethylene glycol, polypropylene glycol, and the like.

The antifogging agent is preferably liquid at room temperature (25°C), more preferably an aliphatic alcohol fatty acid ester, and particularly preferably diglycerol oleate, since it exerts its effect by bleeding out onto the surface of the film. .

The content of the antifogging agent in the resin composition of the present film is preferably 0.1 to 12% by mass, more preferably 1 to 8% by mass, and 1.5 to 6% by mass. It is even more preferable. By being within the above range, the amount of antifogging agent that bleeds onto the film surface tends to be appropriate, and the antifogging properties and handling properties of the film tend to be good.

As mentioned above, in order to effectively improve the antifogging properties of the film, it is preferable to incorporate the antifogging agent into the resin composition of layer (I) of the present film. It is preferable to incorporate it into a resin composition of a layer other than layer (I), for example, a functional layer to be described later, because it facilitates further improvement of the antifogging properties of the film.

In addition, the resin composition may include antioxidants, heat stabilizers, antioxidants, UV absorbers, anti-blocking agents, light stabilizers, compatibilizers, colorants, etc., as long as they do not impair the performance of the film. can be appropriately blended. These may be used alone or in combination of two or more.

As the colorant, one having a maximum absorption wavelength in the range of 600 to 750 nm at 380 to 750 nm can be suitably used, and examples of such a colorant include iron(III) hexacyanoferrate(II). , copper phthalocyanine, cobaltous oxide/aluminum oxide mixture, indigo, ultramarine, etc.

Further, the resin composition may contain recycled raw materials within a range that does not impair the effects of the present invention. The recycled raw materials include, for example, trimming loss that occurs when cutting and trimming both ends of a produced film, films produced in the early stages of production immediately after restarting a production machine that had been stopped, and defective molded products. This includes losses that do not result in products being sold. Thereby, waste of materials can be eliminated and material costs can be reduced.

The layer (I) is obtained by forming a film from the resin composition. The thickness of the layer (I) is preferably from 0.1 to 10 μm, and preferably from 0.1 to 10 μm, since the thinner the layer (I), the better the economical efficiency, but if it is too thin, there is a concern that film formability, productivity, and adhesiveness will decrease. The thickness is more preferably 2 to 5 μm, even more preferably 0.3 to 3 μm, and particularly preferably 0.6 to 2.6 μm. In addition, when this film has multiple layers (I), the thickness of each layer (I) should just be within the said range.

This film has antibacterial properties by adjusting the content of the inorganic antibacterial agent contained in the resin composition forming layer (I) present on at least one of the front and back surfaces of the film within the above-mentioned range. and excellent adhesion to objects to be packaged such as containers.

[Functional layer]
As described above, this film is composed of at least two layers including layer (I), and preferably has a functional layer for imparting a function in addition to layer (I). When the present film has a functional layer, it is possible to impart functionality such as heat resistance, rigidity, strength, impact resistance, and barrier properties to the present film. Further, the number of functional layers may be one, or two or more.

The functional layer is preferably made of a resin composition containing a thermoplastic resin as a main component.
Examples of the thermoplastic resin include polyamide resin, polyethylene resin, polypropylene resin, norbornene resin, polyester resin, vinyl alcohol resin, ethylene-vinyl alcohol resin, polystyrene resin, polyacrylic resin, etc. At least one functional resin selected from these can be selected.
Among these, polyamide resins are preferred. That is, the present film preferably has a functional layer made of a resin composition containing a polyamide resin as a main component.

[Polyamide resin]
Polyamide resin can provide heat resistance and barrier properties.
Examples of polyamide resins include hexamethylene diamine, decamethylene diamine, dodecamethylene diamine, trimethylhexamethylene diamine, 1,3- or 1,4-bis(aminomethyl)cyclohexane, bis(p-aminocyclohexylmethane), Aliphatic, cycloaliphatic, aromatic diamines such as m- or p-xylylene diamine and aliphatic, cycloaliphatic, aromatic diamines such as adipic acid, suberic acid, sebacic acid, cyclohexanedicarboxylic acid, terephthalic acid, isophthalic acid, etc. Polyamide resins obtained by polycondensation with group dicarboxylic acids, polyamide resins obtained by condensation of aminocarboxylic acids such as ε-aminocaproic acid and 11-aminoundecanoic acid, and lactams such as ε-caprolactam and ε-laurolactam. Examples include the obtained polyamide resins and copolymerized polyamide resins thereof. Among these, aliphatic polyamide resins are preferred from the viewpoint of heat resistance and barrier properties necessary for food packaging films, and raw material costs.

Specifically, for example, polyamide-6, polyamide-6,6, polyamide-6,10, polyamide-9, polyamide-11, polyamide-12, polyamide-6/6,6, polyamide-6/6,10, Preferred examples include polyamide-6/11. From the viewpoint of moldability, polyamide-6 is preferably used with a melting point of 170 to 250°C, and since food packaging films may be heated in a microwave oven, it is preferred to use polyamide-6 from the viewpoint of heat resistance.

[Polyethylene resin]
Polyethylene resin is preferable because it has excellent mechanical properties at low temperatures and can impart cold resistance.
As the polyethylene resin, the same polyethylene resin as explained in the layer (I) can be used.
Among these, polyethylene resins include low density polyethylene, linear low density polyethylene, linear very low density polyethylene, ethylene-vinyl acetate copolymer (EVA), ethylene-acrylic acid ester copolymer, and ethylene-methacrylic ester copolymer. It is preferably at least one selected from the group consisting of polymers and ionomer resins, and especially, from the viewpoint of heat resistance, α-olefin selected from 1-butene, 1-hexene, and 4-methylpentene-1. Linear low density polyethylene containing as a comonomer is particularly preferred.

[Polypropylene resin]
Polypropylene resin is preferable because it can impart strength and heat resistance.
The polypropylene resin may be, for example, a propylene homopolymer, or a polypropylene copolymer such as a random copolymer or block copolymer in which propylene is the main monomer and other copolymerizable monomers are used. Bye.

Examples of the other copolymerizable monomers include α-olefins having 2 to 20 carbon atoms such as ethylene, 1-butene, 1-hexene, 4-methylpentene-1, and 1-octene; divinylbenzene; , 4-cyclohexadiene, dicyclopentadiene, cyclooctadiene, ethylidenenorbornene, and the like. These may be used alone or in combination of two or more.

Specific examples of the polypropylene copolymers include propylene-ethylene copolymers, propylene-α-olefin copolymers, propylene-ethylene-butene-1 copolymers, and propylene-ethylene-α-olefin copolymers. , block polypropylene, random polypropylene, homopropylene, and the like.

[Norbornene resin]
Norbornene-based resins are preferred in that they can impart heat resistance and moisture resistance.
The norbornene-based resin is a resin having a norbornene skeleton, and includes, for example, a cyclic olefin polymer (COP) and a cyclic olefin copolymer (COC).

[Polyester resin]
Polyester resins are preferred because they can impart heat resistance, gas barrier properties, and impact resistance. The polyester resin is a resin obtained by copolymerizing a diol component and a dicarboxylic acid component, for example.

Examples of the diol component include ethylene glycol, 1,2-propanediol, 1,3-propanediol, neopentyl glycol, 1,3-butanediol, 1,4-butanediol, 1,5-pentanediol, 1,6-hexanediol, cyclohexanedimethanol, diethylene glycol, triethylene glycol, polyalkylene glycol, tetramethylcyclobutanediol, 2,2-bis(4-hydroxyethoxyphenyl)propane, 4,4'-thiodiphenol, bisphenol A, 4,4'-methylene diphenyl, 4,4'-hydroxybiphenol, dihydroxybenzene, etc. can be mentioned, and these diol components may be used alone or in combination of two or more. good.

Examples of the dicarboxylic acid component include aromatic dicarboxylic acids such as terephthalic acid, isophthalic acid, diphenylcarboxylic acid, diphenylsulfonedicarboxylic acid, diphenoxyethanedicarboxylic acid, 5-sodium sulfoisophthalic acid, and phthalic acid, oxalic acid, and succinic acid. , aliphatic dicarboxylic acids such as eicoic acid, adipic acid, sebacic acid, dimer acid, dodecanedioic acid, maleic acid, and fumaric acid; alicyclic dicarboxylic acids such as cyclohexanedicarboxylic acid; Examples include functional acids. These dicarboxylic acid components may be used alone or in combination of two or more.

Specific examples of the polyester resin include polyethylene terephthalate, polyethylene naphthalate, glycol-modified polyethylene terephthalate, and the like.

[Ethylene-vinyl alcohol resin]
Ethylene-vinyl alcohol resin is preferable because it has excellent gas barrier properties.
Ethylene-vinyl alcohol resin is a resin obtained by saponifying an ethylene-vinyl ester copolymer, which is a copolymer of ethylene and a vinyl ester monomer, and usually contains 20 to 60 moles of ethylene units. %include.

Examples of the vinyl ester monomer include vinyl acetate, vinyl formate, vinyl propionate, vinyl valerate, vinyl butyrate, vinyl isobutyrate, vinyl pivalate, vinyl caprate, vinyl laurate, vinyl stearate, vinyl versatate, and the like. and aromatic vinyl esters such as vinyl benzoate. Generally, only one type of aliphatic vinyl ester having 3 to 20 carbon atoms is used, but two or more types may be used in combination if necessary. Among them, vinyl acetate is used as the vinyl ester monomer because of its market availability and good efficiency in treating impurities during production.

[Polystyrene resin]
Polystyrene resins are preferred because they can impart stiffness and strength to the film.
The polystyrene resin is a resin having a styrene structure as part or all of the repeating unit, such as styrene, α-methylstyrene, o-methylstyrene, p-methylstyrene, p-chlorostyrene, p-nitrostyrene, Styrenic monomers such as p-aminostyrene, p-carboxystyrene, p-phenylstyrene, ethylene, propylene, butadiene, isoprene, acrylonitrile, methacrylonitrile, α-chloroacrylonitrile, methyl acrylate, methyl methacrylate, Examples include copolymers with other monomers such as ethyl acrylate, ethyl methacrylate, acrylic acid, methacrylic acid, maleic anhydride, and vinyl acetate. Examples of the polystyrene resin include polystyrene mixed with a small amount of butadiene rubber particles, so-called high impact polystyrene (HIPS).

The resin composition constituting the functional layer includes various additives, antioxidants, heat stabilizers, antioxidants, UV absorbers, anti-blocking agents, as explained in the resin composition constituting layer (I), It may contain a light stabilizer, a compatibilizer, a coloring agent, and a recycled raw material, and these may be used alone or in combination of two or more. Moreover, these contents may also be in accordance with the contents explained for the resin composition constituting layer (I).

The thickness of the functional layer is preferably from 0.1 to 10 μm, and from 0.3 to 7.0 μm, because the thinner the thickness, the better the economic efficiency, but if it is too thin, there is a concern that film formability and productivity will decrease. The thickness is more preferably 5 μm, even more preferably 0.5 to 5 μm, and particularly preferably 0.7 to 3.5 μm. In addition, when this film has multiple functional layers, the thickness of each functional layer should just be within the said range.

[Other layers]
This film may have layers other than the layer (I) and the functional layer for the purpose of improving mechanical properties and interlayer adhesion, etc., without exceeding the spirit of the present invention.

In particular, when layer (I) and the functional layer are mainly composed of a polar thermoplastic resin and a non-polar thermoplastic resin, respectively, there is a possibility of delamination between the layers, and in order to improve interlayer adhesion, an adhesive resin layer is It is preferable to provide The thermoplastic resin constituting the adhesive resin layer is not particularly limited, but preferably contains a modified polyolefin resin into which a polar group has been introduced.

In addition, the thermoplastic resin constituting the adhesive resin layer is a mixture of one or more of acid-modified polyolefin resin and linear low-density polyethylene, etc., in order to achieve both suitable interlayer adhesive strength and raw material cost. Good too.

The mixing ratio for achieving both suitable interlayer adhesion and raw material cost is preferably linear low density polyethylene/acid modified polyolefin = 90 to 40/10 to 60, more preferably linear low density polyethylene/acid modified polyolefin = 80-60/20-40. If the ratio is within the above range, it is possible to maintain the interlayer adhesive strength between the highly polar thermoplastic resin and the non-polar thermoplastic resin, and also to suppress an increase in raw material costs.

Further, by introducing other layers, it is preferable that various functions such as barrier properties, heat resistance, antifogging properties, and impact resistance can be imparted to the film.

The thickness of the other layers is preferably from 0.01 to 10 μm, and from 0.05 to 7 μm, since the thinner the thickness, the better the economic efficiency, but if it is too thin, there is a concern that film formability and productivity will decrease. .5 μm is more preferred, 0.1 to 5 μm is even more preferred, 0.15 to 3 μm is particularly preferred, and 0.2 to 2 μm is most preferred. In addition, when this film has multiple other layers, the thickness of each other layer should just be within the said range.

[Layer structure of film]
As mentioned above, the present film may be composed of two layers having layer (I) on at least one of the front and back surfaces of the film.
When functional layers other than layer (I) and other layers are layer (II), layer (III), etc., the preferred layer structure of the present film is specified below.
For example, when the present film has layer (I) and layer (II), in addition to the two-layer structure of layer (I)/layer (II), layer (I)/layer (II)/layer (I), etc. A two-type, three-layer structure can be adopted. In addition, when the present film has, for example, layer (I), layer (II), and layer (III), a three-layer structure of layer (I)/layer (II)/layer (III), layer (I) A five-layer structure of three types, such as / layer (II) / layer (III) / layer (II) / layer (I), can be adopted.
Furthermore, when the present film has, for example, layer (I) and layers (II) to (IV), it has a four-layer structure of layer (I)/layer (II)/layer (III)/layer (IV). , it is possible to adopt a structure such as a four-type seven-layer structure such as layer (I) / layer (II) / layer (III) / layer (IV) / layer (III) / layer (II) / layer (I). can.
In this film, there are no limitations on the number of layers, the order of layers other than layer (I), and the types and numbers of functional layers and other layers.

<Production method of this film>
Hereinafter, the manufacturing method of this film will be explained, but it is not limited to the following manufacturing method.

First, when the constituent raw materials of each layer are a mixed composition, the constituent raw materials of each layer are mixed in advance to prepare a resin composition. Moreover, it is preferable that the resin composition is pelletized if necessary. In this case, the mixing method may be, for example, pre-compounding using a kneader, Banbury mixer, kneading machine such as a roll, single-screw or twin-screw extruder, or dry blending of each raw material. It may be directly charged into the film extruder. Furthermore, since additives such as antibacterial agents, colorants, and antioxidants are also commercially available in the form of masterbatches, they can be mixed more appropriately by using these. In any mixing method, it is necessary to take into account deterioration due to oxidation and decomposition of the raw materials, but pre-compounding is preferable in order to mix uniformly.

Next, the constituent raw materials for each layer may be put into separate extruders, melt-extruded, coextruded by T-die molding or inflation molding, and then laminated.
At this time, it is practically preferable to form a film by directly drawing the molten material extruded from the T-die while rapidly cooling it with a casting roll or the like.

In addition, if the heat resistance and cutability of this film are important, the melt-extruded film is cooled and solidified using a cooling roll, then heated to below the crystallization temperature of the resin, and the speed difference between the nip rolls is used to cut the film. It is preferable to longitudinally stretch in the machine direction.

As for the stretching temperature, the temperature of the extruded film is preferably set in the range of 70 to 115°C, more preferably in the range of 90 to 110°C. Further, the stretching ratio is preferably within the range of 1.1 to 5.0 times, more preferably within the range of 1.5 to 3.0 times. If the stretching ratio is within this range, the cuttability can be improved without causing troubles such as breakage and whitening of the extruded film.

The film obtained in this manner may be subjected to longitudinal stretching between heated rolls, various types of heat setting, Heat treatment such as aging may also be performed.

In addition, this film can be subjected to treatments such as corona treatment and aging, as well as surface treatments such as printing and coating, in order to impart or promote antifogging properties, antistatic properties, adhesive properties, etc. good.

The thickness (overall) of the present film is preferably in the range used as a food packaging film, specifically 30 μm or less, more preferably 5 to 30 μm, and even more preferably 6 to 20 μm.

[Film properties]
The film thus obtained preferably has the following physical properties.

[Adhesiveness]
The adhesive strength of layer (I) of the present film to glass is preferably 50 mN or more, more preferably 55 mN or more, and even more preferably 60 mN or more. If it is 50 mN or more, sufficient adhesiveness tends to be obtained when packaging objects such as foods. Note that the upper limit is usually 300 mN, and if the adhesive force is 300 mN or less, even when packages wrapped in films are stacked, the problem that the packages stick to each other tends to be less likely to occur. Note that the adhesive strength to glass is measured by the method described in Examples.

[Exposure amount of antibacterial agent]
Layer (I) in this film is characterized in that it exhibits antibacterial properties by reducing the content of an inorganic antibacterial agent. The exposure amount of inorganic antibacterial agents can be cited as a parameter that indicates the development of antibacterial properties.
The exposed amount of the inorganic antibacterial agent is preferably 0.013 to 1.5%, more preferably 0.014 to 1.2%, and more preferably 0.015 to 1.0% based on the area of layer (I). More preferably, 0.02 to 0.8% is particularly preferred.
The exposure amount of the inorganic antibacterial agent was determined by observing the surface of layer (I) using a scanning electron microscope equipped with energy dispersive X-ray spectroscopy, creating an elemental map derived from the inorganic antibacterial agent, and observing it. It is obtained by calculating the area of the inorganic antibacterial agent in the area as an area ratio.

[Antibacterial]
The antibacterial property of this film can be evaluated by the antibacterial activity value shown in JIS Z2801 (2012) antibacterial evaluation method, and it is preferable that the antibacterial activity value is 2.0 or more. In this evaluation method, antibacterial properties against Staphylococcus aureus and E. coli are evaluated, and if the antibacterial activity value is 2.0 or more, it can be judged that the product has excellent antibacterial properties.

[Total light transmittance]
In terms of transparency, the total light transmittance of this film measured by the light transmittance measuring method described in JIS K7136 (2000) is preferably 80% or more, and more preferably 85% or more.

The resulting film can be manufactured into a product by trimming both ends and then slitting it to a desired width. In addition, a film roll with a length of 1,000 m or more is collected, and then in a separate process, it is changed into a small roll of film for food packaging with a length of 100 m or less, and then packed in a carton box with a cutter blade. I can do it. If productivity or economy is important, it is desirable to separate small rewinding and boxing processes.

Usually, a carton box with a cutter blade has a front plate (5), a bottom plate (4), a rear plate (6), a lid plate (8), and a cover plate (7) in this order, as shown in Figure 1. A long decorative box that is connected via a ridgeline and has side plate portions (3) on both sides is often used, and the cutter blade (1) is fixed to the tip of the cover plate (7). Further, the cutter blade (2) is fixed to the ridgeline portions of the front plate (5) and the bottom plate (4). The position of the cutter blade is not limited to either position, but in the case of small roll film for commercial food packaging used in the restaurant industry, the cutter blade is placed on the front plate (5) and the bottom plate. It is desirable that it is fixed to the ridgeline (4).

The material of the cutter blade attached to the carton box is not particularly limited, and examples include cutter blades made of paper, plastic, and metal. Among these, a saw blade made of plastic or metal is preferable from the viewpoint of durability of the cutter blade.

EXAMPLES The present invention will be explained in more detail below with reference to Examples, but the present invention is not limited in any way by these examples. In addition, various measured values and evaluations regarding the films and their materials shown in this specification were performed as follows. Here, the flow direction of the film from the extruder is referred to as MD, and the direction perpendicular thereto is referred to as TD.

[Film evaluation]
(1) Adhesive strength Layer (I) of the test piece with a width of 300 mm and a length of 460 mm is adhered to glass with a length of 220 mm, and the glass with this test piece pasted is tested using a tensile tester (Shimadzu) using a jig. Seisakusho Co., Ltd., Autograph AGS-J) was set at an angle of 90° to the tensile direction, and the end of the test piece was fixed to the grip part of the chuck so that the distance between the chucks was 100 mm. The film was peeled off at a speed of 200 mm/min until it was peeled off. The value obtained by subtracting the film mass from the maximum test force at this time was defined as the adhesive force (mN), and the average value of the three measurements was defined as the adhesive force (mN) of the film.

(2) Antibacterial test Antibacterial property is determined by inoculating a test piece with Staphylococcus aureus and Escherichia coli based on the antibacterial test described in JIS Z2801 (2012), calculating the antibacterial activity value using the following formula. Evaluation was performed using evaluation criteria.
Antibacterial activity value = Log (N1/N2)
In the above formula, N1 is the number of bacteria on the unprocessed test piece (control side) after culturing at 35°C and 90% RH for 24 hours, and N2 is the number of bacteria on the test piece made of the film of each Example and Comparative Example. This is the number of bacteria after culturing for 24 hours at 35°C and 90% RH.
From the obtained antibacterial activity values, antibacterial activity values of 2 or more were evaluated as having antibacterial properties, and those less than 2 were evaluated as having no antibacterial properties.

(3) Amount of exposure to antibacterial agents The amount of exposure to antibacterial agents was determined by observing the surface of layer (I) using a scanning electron microscope equipped with energy dispersive X-ray spectroscopy, and creating a map of elements derived from antibacterial agents. Then, the antibacterial agent area in the observed area was calculated as an area ratio.

(4) Transparency (total light transmittance)
The total light transmittance was measured using a haze meter (manufactured by Nippon Denshoku Kogyo Co., Ltd., NDH-5000) according to the light transmittance measurement method described in JIS K7136 (2000).

The raw materials used in each example and comparative example are as follows.
〔Thermoplastic resin〕
・LDPE1: Linear low-density polyethylene with 1-butene as a comonomer (density: 0.913 g/cm ³ , MFR: 2.0 g/10 min)
・LDPE2: Linear low-density polyethylene with 1-hexene as a comonomer (density: 0.937 g/cm ³ , MFR: 2.3 g/10 min)
- Thermoplastic resin A1: As thermoplastic resin A1, LDPE1, LDPE2, and an antifogging agent whose main components are diglycerol oleate are mixed in a mass ratio of LDPE1/LDPE2/antifogging agent = 77/20/3, The mixture was put into a single screw extruder set at an extrusion temperature of 200 to 245°C and melted and kneaded to obtain thermoplastic resin A1.
・Thermoplastic resin A2: As thermoplastic resin A2, LDPE1 and LDPE2 are mixed at a mass ratio of LDPE1/LDPE2 = 80/20, and melted by putting it into a single screw extruder set at an extrusion temperature of 200 to 245 ° C. The mixture was kneaded to obtain thermoplastic resin A2.

[Inorganic antibacterial agent]
・Inorganic antibacterial agent B1: Silver-supported zirconium phosphate (average particle size: 0.9 μm, silver ion content: 0.4% by mass)
・Inorganic antibacterial agent B2: Silver-supported zirconium phosphate (average particle size: 0.9 μm, silver ion content: 1.1% by mass)

[Polyamide resin]
・Polyamide resin C1: Polyamide-6 (density: 1.13 g/cm ³ , melting point: 225°C)

[Colored resin]
・Colored resin D1: Colored resin D1 is a color MB/color MB containing a colorant mainly composed of copper phthalocyanine (pigment concentration: 12.5% by mass, base material: polyethylene) and LDPE1 in a mass ratio. After mixing at a ratio of LDPE1=5/95, the mixture was put into a single-screw extruder set at a temperature of 180 to 190°C and melt-kneaded to produce the mixture.

[Adhesive resin]
・Adhesive resin E1: Acid-modified polyethylene (Mitsui Chemicals: Admer NF614)

[Other resins]
・Other resin F1: PP-PE random copolymer (propylene/ethylene content ratio = 87/13 (mass ratio), MFR: 2.0 g/10 min)
・Other resin F2: Olefin mixture (acid modified polypropylene resin, MFR: 3.0 g/10 min, random polypropylene resin (propylene/ethylene content ratio = 97/3, MFR: 3.0 g/10 min) and hydrogenated petroleum resin (Arakawa Chemical Industry Co., Ltd.: Alcon P125) mixture, mass ratio: acid-modified polypropylene resin/random polypropylene resin/hydrogenated petroleum resin = 70/10/20)
・Other resin G1: Recycled raw material from both ends of the film and the roll of the film

<Example 1>
A 7-layer film of 4 types having layers (I) to (IV) was formed by the following method.
As a resin composition forming layer (I), a thermoplastic resin A1 and an inorganic antibacterial agent B1 were mixed at a mass ratio of 99.9/0.1, and extrusion was performed using a single screw with a set temperature of 200 to 245°C. A product was prepared by putting it into an extruder and melting and kneading it.

As the resin composition forming layer (II), colored resin D1, other resin F1, other resin F2, and other resin G1 are mixed in a mass ratio of colored resin D1/other resin F1/other resin F2/other resin G1= Mixed in a ratio of 6/14/30/50, and further added 3.8 parts by mass of "O-71DE" manufactured by Riken Vitamin Co., Ltd. as an antifogging agent containing diglycerin oleate as a main component to 100 parts by mass of the mixture. was added and melted and kneaded by putting it into a co-directional twin-screw extruder set at an extrusion temperature of 200 to 240°C to prepare a product.

As a resin composition forming layer (III), LDPE1, colored resin D1, and adhesive resin E1 are mixed at a mass ratio of LDPE1/colored resin D1/adhesive resin E1 = 70/5/25. The mixture was then put into a single-screw extruder and melt-kneaded to prepare a product.

A polyamide resin C1 was prepared as a resin composition for forming layer (IV).

Then, each resin composition as described above was put into a separate extruder for each layer, and after melting and kneading, the molten resins were combined to form layer (I) at a 7-layer T-die temperature of 245°C and a die gap of 1mm. / Layer (II) / Layer (III) / Layer (IV) / Layer (III) / Layer (II) / Layer (I) are coextruded in this order and rapidly cooled with a cast roll set at a temperature of 30°C. Total thickness 7 μm [Layer (I) / Layer (II) / Layer (III) / Layer (IV) / Layer (III) / Layer (II) / Layer (I) = 1.26 μm / 1.28 μm / 0.35 μm /1.22 μm/0.35 μm/1.28 μm/1.26 μm] was formed into a film roll. Thereafter, the film was changed into a 100 m roll and packed into a carton box to obtain a small film for food packaging.

<Example 2>
As a resin composition forming layer (I), a thermoplastic resin A1 and an inorganic antibacterial agent B1 were mixed at a mass ratio of 99.6/0.4, and extrusion was performed using a uniaxial extrusion temperature set at 200 to 245°C. A product was prepared by putting it into an extruder and melting and kneading it.

The rest was the same as in Example 1, with a total thickness of 7 μm [Layer (I) / Layer (II) / Layer (III) / Layer (IV) / Layer (III) / Layer (II) / Layer (I) = 1 A film roll of .26 μm/1.28 μm/0.35 μm/1.22 μm/0.35 μm/1.28 μm/1.26 μm was formed. Thereafter, the film was changed into a small roll of 100 m and packed into a carton box equipped with a metal cutter blade to obtain a small film for food packaging.

<Example 3>
As a resin composition forming layer (I), a thermoplastic resin A1 and an inorganic antibacterial agent B1 were mixed at a mass ratio of 99.9/0.1, and extrusion was performed using a single screw with a set temperature of 200 to 245°C. The mixture was put into an extruder and melted and kneaded.

For the resin composition forming layer (II), LDPE1 and other resin G1 were mixed in a mass ratio of LDPE1/other resin G1 = 48/52, and extruded in the same direction at a set temperature of 200 to 240°C. A product was prepared by putting it into a twin-screw extruder and melt-kneading it.

For the resin composition forming layer (III), adhesive resin E1 and LDPE1 were mixed at a mass ratio of LDPE1/adhesive resin E1 = 75/25, and the mixture was put into a single screw extruder and melted and kneaded. prepared.

For the rest, the total thickness was 7 μm as in Example 1 [Layer (I)/Layer (II)/Layer (III)/Layer (IV)/Layer (III)/Layer (II)/Layer (I) = 1 A film roll of .27 μm/1.27 μm/0.35 μm/1.22 μm/0.35 μm/1.27 μm/1.27 μm was formed. Thereafter, the film was changed into a small roll of 100 m and packed into a carton box equipped with a metal cutter blade to obtain a small film for food packaging.

<Example 4>
As the resin composition forming layer (I), thermoplastic resin A1 and inorganic antibacterial agent B1 were mixed at a mass ratio of 99.85/0.15, and extrusion temperature was set at 200 to 245°C using a single shaft. A product was prepared by putting it into an extruder and melting and kneading it.

The rest was the same as in Example 3, with a total thickness of 14 μm [Layer (I)/Layer (II)/Layer (III)/Layer (IV)/Layer (III)/Layer (II)/Layer (I) = 2 A film roll of .54 μm/2.56 μm/0.7 μm/2.44 μm/0.7 μm/2.56 μm/2.54 μm was formed. Thereafter, the film was changed into a small roll of 100 m and packed into a carton box equipped with a metal cutter blade to obtain a small film for food packaging.

<Example 5>
As the resin composition forming layer (I), thermoplastic resin A1 and inorganic antibacterial agent B1 were mixed at a mass ratio of 99.85/0.15, and extrusion temperature was set at 200 to 245°C using a single shaft. A product was prepared by putting it into an extruder and melting and kneading it.

For the rest, the total thickness was 7 μm as in Example 3 [Layer (I)/Layer (II)/Layer (III)/Layer (IV)/Layer (III)/Layer (II)/Layer (I) = 1 A film roll of .27 μm/1.28 μm/0.35 μm/1.22 μm/0.35 μm/1.28 μm/1.27 μm was formed. Thereafter, the film was changed into a small roll of 100 m and packed into a carton box equipped with a metal cutter blade to obtain a small film for food packaging.

<Example 6>
As a resin composition forming layer (I), a thermoplastic resin A1 and an inorganic antibacterial agent B1 were mixed at a mass ratio of 99.75/0.25, and extrusion was performed using a single screw with a set temperature of 200 to 245°C. A product was prepared by putting it into an extruder and melting and kneading it.

The rest was the same as in Example 3, with a total thickness of 14 μm [Layer (I)/Layer (II)/Layer (III)/Layer (IV)/Layer (III)/Layer (II)/Layer (I) = 2 A film roll of .54 μm/2.56 μm/0.7 μm/2.44 μm/0.7 μm/2.56 μm/2.54 μm was formed. Thereafter, the film was changed into a small roll of 100 m and packed into a carton box equipped with a metal cutter blade to obtain a small film for food packaging.

<Example 7>
As a resin composition forming layer (I), a thermoplastic resin A1 and an inorganic antibacterial agent B1 were mixed at a mass ratio of 99.75/0.25, and extrusion was performed using a single screw with a set temperature of 200 to 245°C. A product was prepared by putting it into an extruder and melting and kneading it.

For the rest, the total thickness was 7 μm as in Example 3 [Layer (I)/Layer (II)/Layer (III)/Layer (IV)/Layer (III)/Layer (II)/Layer (I) = 1 A film roll of .27 μm/1.28 μm/0.35 μm/1.22 μm/0.35 μm/1.28 μm/1.27 μm was formed. Thereafter, the film was changed into a small roll of 100 m and packed into a carton box equipped with a metal cutter blade to obtain a small film for food packaging.

<Example 8>
As the resin composition forming layer (I), thermoplastic resin A2 and inorganic antibacterial agent B1 were mixed at a mass ratio of 99.75/0.25, and extrusion was carried out using a single screw with a set temperature of 200 to 245°C. A product was prepared by putting it into an extruder and melting and kneading it.

The rest was the same as in Example 3, with a total thickness of 14 μm [Layer (I)/Layer (II)/Layer (III)/Layer (IV)/Layer (III)/Layer (II)/Layer (I) = 2 A film roll of .54 μm/2.56 μm/0.7 μm/2.44 μm/0.7 μm/2.56 μm/2.54 μm was formed. Thereafter, the film was changed into a small roll of 100 m and packed into a carton box equipped with a metal cutter blade to obtain a small film for food packaging.

<Example 9>
As a resin composition forming layer (I), a thermoplastic resin A1 and an inorganic antibacterial agent B1 were mixed at a mass ratio of 99.75/0.25, and extrusion was performed using a single screw with a set temperature of 200 to 245°C. A product was prepared by putting it into an extruder and melting and kneading it.

For the rest, the total thickness was 7 μm as in Example 3 [Layer (I) / Layer (II) / Layer (III) / Layer (IV) / Layer (III) / Layer (II) / Layer (I) = 1 A film roll of .27 μm/1.28 μm/0.35 μm/1.22 μm/0.35 μm/1.28 μm/1.27 μm was formed. Thereafter, the film was changed into a small roll of 100 m and packed into a carton box equipped with a metal cutter blade to obtain a small film for food packaging.

<Example 10>
As the resin composition forming layer (I), thermoplastic resin A1 and inorganic antibacterial agent B1 were mixed at a mass ratio of 99.65/0.35, and extruded using a single screw with a set temperature of 200 to 245°C. A product was prepared by putting it into an extruder and melting and kneading it.

The rest was the same as in Example 3, with a total thickness of 14 μm [Layer (I)/Layer (II)/Layer (III)/Layer (IV)/Layer (III)/Layer (II)/Layer (I) = 2 A film roll of .54 μm/2.56 μm/0.7 μm/2.44 μm/0.7 μm/2.56 μm/2.54 μm was formed. Thereafter, the film was changed into a small roll of 100 m and packed into a carton box equipped with a metal cutter blade to obtain a small film for food packaging.

<Example 11>
As the resin composition forming layer (I), thermoplastic resin A1 and inorganic antibacterial agent B1 were mixed at a mass ratio of 99.65/0.35, and extruded using a single screw with a set temperature of 200 to 245°C. A product was prepared by putting it into an extruder and melting and kneading it.

For the rest, the total thickness was 7 μm as in Example 3 [Layer (I) / Layer (II) / Layer (III) / Layer (IV) / Layer (III) / Layer (II) / Layer (I) = 1 A film roll of .27 μm/1.28 μm/0.35 μm/1.22 μm/0.35 μm/1.28 μm/1.27 μm was formed. Thereafter, the film was changed into a small roll of 100 m and packed into a carton box equipped with a metal cutter blade to obtain a small film for food packaging.

<Example 12>
As the resin composition forming layer (I), thermoplastic resin A1 and inorganic antibacterial agent B2 were mixed at a mass ratio of 98.6/1.4, and extrusion was performed using a single screw with a set temperature of 200 to 245°C. A product was prepared by putting it into an extruder and melting and kneading it.

As a resin composition forming layer (II), LDPE1, other resin G1, and an antifogging agent are mixed in a mass ratio of LDPE1/other resin G1/antifogging agent = 46/50/4, and the extrusion setting temperature is A product was prepared by melt-kneading the mixture in a co-directional twin-screw extruder set at 200 to 240°C.

For the rest, the total thickness was 7 μm as in Example 3 [Layer (I) / Layer (II) / Layer (III) / Layer (IV) / Layer (III) / Layer (II) / Layer (I) = 1 A film roll of .26 μm/1.28 μm/0.34 μm/1.25 μm/0.34 μm/1.28 μm/1.26 μm was formed. Thereafter, the film was changed into a small roll of 100 m and packed into a carton box equipped with a metal cutter blade to obtain a small film for food packaging.

<Example 13>
As a resin composition forming layer (I), a thermoplastic resin A1 and an inorganic antibacterial agent B1 were mixed at a mass ratio of 97.4/2.6, and extrusion was performed using a uniaxial extrusion temperature set at 200 to 245°C. A product was prepared by putting it into an extruder and melting and kneading it.

For the rest, the total thickness was 7 μm [Layer (I)/Layer (II)/Layer (III)/Layer (IV)/Layer (III)/Layer (II)/Layer (I) = 1 in the same manner as in Example 12. A film roll of .26 μm/1.28 μm/0.34 μm/1.25 μm/0.34 μm/1.28 μm/1.26 μm was formed. Thereafter, the film was changed into a small roll of 100 m and packed into a carton box equipped with a metal cutter blade to obtain a small film for food packaging.

<Comparative example 1>
A resin composition for forming layer (I) was prepared by melting and kneading thermoplastic resin A1 into a single-screw extruder set at an extrusion temperature of 200 to 245°C.

For the rest, the total thickness was 7 μm as in Example 1 [Layer (I)/Layer (II)/Layer (III)/Layer (IV)/Layer (III)/Layer (II)/Layer (I) = 1 A film roll of .26 μm/1.28 μm/0.35 μm/1.22 μm/0.35 μm/1.28 μm/1.26 μm was formed. Thereafter, the film was changed into a small roll of 100 m and packed into a carton box equipped with a metal cutter blade to obtain a small film for food packaging.

<Comparative example 2>
As a resin composition forming layer (I), thermoplastic resin A1 and inorganic antibacterial agent B1 were mixed at a mass ratio of 99.99/0.01, and extrusion was performed using a single screw with a set temperature of 200 to 245°C. A product was prepared by putting it into an extruder and melting and kneading it.

For the rest, the total thickness was 7 μm as in Example 1 [Layer (I)/Layer (II)/Layer (III)/Layer (IV)/Layer (III)/Layer (II)/Layer (I) = 1 A film roll of .26 μm/1.28 μm/0.35 μm/1.22 μm/0.35 μm/1.28 μm/1.26 μm was formed. Thereafter, the film was changed into a small roll of 100 m and packed into a carton box equipped with a metal cutter blade to obtain a small film for food packaging.

The total light transmittance, adhesive strength, antibacterial property, and amount of agent exposure of the food packaging films of Examples 1 to 13 and Comparative Examples 1 and 2 were evaluated by the methods described above. The structure of each food packaging film and the evaluation results are shown in Table 1 below. The antifogging agent in Table 1 indicates the mass % of the antifogging agent in each layer.

From the results in Table 1, it can be seen that the films of Examples 1 to 13 have excellent adhesive strength and antibacterial properties. On the other hand, the films of Comparative Example 1, which did not contain an inorganic antibacterial agent, and Comparative Example 2, which contained too little inorganic antibacterial agent, had poor antibacterial properties.

This film exhibits good adhesion to adherends and has high antibacterial properties, so it is useful as a food packaging film.

1 Cutter blade 2 Cutter blade 3 Side plate 4 Bottom plate 5 Front plate 6 Rear plate 7 Cover plate 8 Cover plate

Claims (13)

A food packaging film having a layer (I) made of a resin composition containing a thermoplastic resin and an inorganic antibacterial agent on at least one of the front and back surfaces of the film, wherein the layer (I) is made of a resin composition containing a thermoplastic resin and an inorganic antibacterial agent. A food packaging film having a content of 0.02 to 5% by mass. The inorganic antibacterial agent is an inorganic compound in which metal ions are supported on an inorganic carrier, the metal species of the metal ions is at least one selected from the group consisting of silver, copper, and zinc; The food packaging film according to claim 1, wherein the inorganic carrier is at least one selected from the group consisting of zeolite, zirconium phosphate, and glass. The food packaging film according to claim 2, wherein the content of metal ions in the inorganic antibacterial agent is 0.01 to 20% by mass based on the total weight of the inorganic antibacterial agent. The food packaging film according to any one of claims 1 to 3, wherein the layer (I) has a thickness of 0.1 to 10 μm. The food packaging film according to any one of claims 1 to 3, wherein the thermoplastic resin is a polyolefin resin. The food packaging film according to any one of claims 1 to 3, wherein the adhesive force between the layer (I) and the glass is 50 mN or more. The food packaging film according to any one of claims 1 to 3, having a thickness of 30 μm or less. The food packaging film according to any one of claims 1 to 3, wherein the inorganic antibacterial agent has an average particle size of 3 μm or less. The food packaging according to any one of claims 1 to 3, wherein the resin composition further contains an antifogging agent, and the content of the antifogging agent in the resin composition is 0.1 to 12% by mass. Film for. The food packaging film according to any one of claims 1 to 3, wherein the food packaging film has a functional layer. The food packaging film according to any one of claims 1 to 3, wherein the functional layer is a layer made of a resin composition containing a polyamide resin as a main component. A small roll film for food packaging, comprising the food packaging film according to any one of claims 1 to 3. The small roll film for food packaging according to claim 12, which is housed in a carton box.

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