JP2020152449A - Film for food packaging and small wound film for food packaging - Google Patents

Abstract

To provide a film for food packaging that has superior stickiness to an adherend, and is free of blocking even during storage in a winding state.SOLUTION: There is provided a film for food packaging consisting of at least two layers which are a layer A formed of a thermoplastic resin composition essentially including thermoplastic resin of (I) to (III) and a layer B principally including thermoplastic resin of (IV), wherein a storage elastic modulus (E') measured by a dynamic viscoelasticity measuring method at 0-20°C with a vibration frequency of 10 Hz is 100 MPa or higher and 1 GPa or lower, and a value of loss tangent (tanδ) is 0.08 or higher and 0.5 or lower. Here, (I) is thermoplastic resin selected from propylene-ethylene copolymers etc. of less than 6 mass% in a component amount other than propylene components, (II) is thermoplastic resin selected from petroleum resin etc., and (III) is thermoplastic resin selected from propylene-ethylene copolymers etc. of 6 mass% or larger in a component amount other than propylene components.SELECTED DRAWING: None

Description

The present invention relates to a film for food packaging. More specifically, the present invention is particularly excellent in adhesiveness to an adherend such as a container from a refrigerated environment to a room temperature environment, and is excellent in heat resistance, film payability, and food safety. It relates to a food packaging film containing no chlorine or polyvinyl chloride plasticizer, which can be suitably used as a small roll film.

Food packaging films are used as films for wrapping cooked foods on pottery or plastic containers. Conventionally, as a food packaging film used in the food service industry such as a general household, a hotel, or a restaurant, a film containing polyvinylidene chloride resin or polyvinyl chloride resin as a main raw material has been used. This is the cutability when cutting to a predetermined length with a saw blade when stored in a carton box with a cutter blade, the adhesiveness when covering an adherend such as a container, and when heating in a microwave oven. This is because the film is excellent in practical heat resistance that does not melt, and therefore has an advantage in terms of quality in food packaging and the usage environment incidental thereto.

However, in recent years, hydrogen chloride gas generated during incineration has been regarded as a problem for polyvinylidene chloride-based films and polyvinyl chloride-based films containing chlorine, and elution of plasticizers for PVC-based films has been regarded as a problem. Further, in the case of a polyvinylidene chloride-based film, the film may be deformed when heated in a microwave oven, and in the case of a polyvinylidene chloride-based film, problems such as whitening may occur when the film comes into contact with boiling water.

Therefore, various materials to replace polyvinylidene chloride resin or polyvinyl chloride resin have been studied, and in particular, various food packaging films using polyolefin resin as a main raw material have been proposed, and are monolayer or other thermoplastic. A film in which a resin is laminated is known.

For example, Patent Document 1 proposes a three-kind, five-layer food packaging film in which a polyamide resin layer is used as an intermediate layer and a polyethylene resin layer is used as front and back layers via an adhesive layer.

On the other hand, food packaging films made mainly of polyolefin resins have lower adhesiveness than polyvinylidene chloride films and polyvinyl chloride films, and have better adhesion when covering adherends such as containers. It is low and easy to peel off. When the film is peeled off from the container, the food stored in the container comes into contact with the outside air, which causes problems such as drying and deterioration of the food. Therefore, in order to improve this, a film in which an additive for improving adhesiveness is added to the front and back layer surfaces of the film in which the container and the film are in contact with each other is known.

For example, Patent Document 2 proposes a food packaging film having a polyamide resin layer as an intermediate layer and a layer containing a polypropylene resin and a thermoplastic resin containing polybutene or polyisobutylene as a main component as front and back layers.

Further, in Patent Document 3, a thermoplastic resin layer containing a polypropylene resin and an olefin-based elastomer is used as an intermediate layer, and a plasticizer for low-density polyethylene and a polyvinyl chloride-based resin as an adhesive adjusting agent and a tack fire as an adhesive-imparting agent are used. A two-kind, three-layer food packaging film having a thermoplastic resin layer containing the above as front and back layers has been proposed.

Japanese Unexamined Patent Publication No. 2003-103724 Japanese Unexamined Patent Publication No. 6-12182 Japanese Unexamined Patent Publication No. 2015-229331

Here, in the film of Patent Document 1, when the film is covered with an adherend such as a container, the loss tangent (tan δ) at 0 ° C to 20 ° C is low, so that the film is peeled off during storage and the food to be stored. May spoil the freshness of.

Further, since the film of Patent Document 2 contains polybutene and polyisobutylene in the front and back layers, when the film is covered with an adherend such as a container, the film is hard to peel off during storage, but the film is stored in a rolled shape. In this case, the adhesiveness adjusting agent may bleed out to block the film, making it difficult to unwind the film.

Since the film of Patent Document 3 contains a small amount of tack fire that develops adhesiveness, it is unlikely to block when the film is stored in a rolled form, but it contains an adhesiveness adjusting agent having a low molecular weight. , These may bleed out at the time of joining, and excessive stickiness may occur on the surface of the film, resulting in poor handleability and insufficient adhesiveness.

The present invention has been made in view of the above circumstances, and when the package containing food is stored at a temperature from refrigeration to room temperature, it has excellent adhesiveness to an adherend and is stored in a roll shape. The purpose is to provide a food packaging film that does not block.

As a result of diligent studies in view of the above problems, the present inventors have found that the above problems can be solved by a film having a specific configuration, and have completed the present invention.

That is, the food packaging film of the present invention contains a layer A composed of a thermoplastic resin composition containing the following thermoplastic resins (I) to (III) as an essential component and the following thermoplastic resin (IV) as main components. A food packaging film composed of at least two layers with layer B.
The storage elastic modulus (E') at 0 to 20 ° C. measured at a vibration frequency of 10 Hz by the dynamic viscoelasticity measuring method of the food packaging film is 100 MPa or more and 1 GPa or less, and the value of loss tangent (tan δ). Is 0.08 or more and 0.5 or less.
(I) At least one thermoplastic selected from propylene-ethylene copolymer, propylene-α-olefin copolymer, block polypropylene, and homopropylene having a component amount other than the propylene component of less than 6% by mass. Resin (II) Petroleum resin, terpene resin, kumaron-inden resin, rosin-based resin, and at least one thermoplastic resin selected from their hydrogenated derivatives (III) Among the following [a] to [c] At least one thermoplastic resin selected from [a] A propylene-ethylene copolymer, a propylene-α-olefin copolymer, and a propylene-ethylene-butene-1 having a component amount other than the propylene component of 6% by mass or more. Copolymer, propylene-ethylene-α-olefin copolymer [b] Copolymer consisting of a vinyl aromatic compound and a conjugated diene, and a hydrogenated derivative thereof [c] Ethylene-α olefin block copolymer weight A coalescence, an ethylene-based copolymer (IV) including an ethylene-α-olefin random copolymer, a polyamide-based resin, a polyethylene-based resin, a polypropylene-based resin, a norbornene-based resin, a polyester-based resin, an ethylene-vinyl alcohol-based copolymer, and a polystyrene. At least one type of thermoplastic resin selected from the based resins

In the food packaging film, when the thermoplastic resin composition of the layer A is 100% by mass, the content of the thermoplastic resin of (I) to (III) is (I) / (II) /. (III) = 1 to 60% by mass / 1 to 40% by mass / 1 to 50% by mass is preferable.

In the food packaging film, the thickness of the layer A is preferably 10% or more and 80% or less of the total thickness of the food packaging film.

The food packaging film preferably further has one or more layers containing a polyethylene resin as a main component.

It is preferable that the food packaging film further has one or more layers containing a polyamide resin as a main component.

In the food packaging film, it is preferable that the heat of crystal melting (ΔHm) in the differential scanning calorimetry is 30 J / g to 90 J / g and the peak temperature of crystal melting (Tm) is 100 ° C. or higher.

In the above-mentioned food packaging film, the storage elastic modulus (E') at 110 ° C. measured at a vibration frequency of 10 Hz is preferably 10 MPa or more by a dynamic viscoelasticity measuring method.

The total thickness of the food packaging film is preferably 30 μm or less.

The present invention is a small roll film for food packaging, wherein the food packaging film according to any one of the above is housed in a carton box with a cutter blade.

According to the present invention, even if the package containing the film of the present invention is stored for a long time in a temperature environment of 0 ° C to 20 ° C, it does not peel off from the adherend and has good adhesion to the adherend. It is possible to provide a film for food packaging having good handleability even when the film of the present invention is used after being stored in a rolled form for a long period of time.

FIG. 1 is a cross-sectional view schematically showing the structure of the food packaging film according to the present embodiment.

Hereinafter, a food packaging film as an example of the 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 of allowing other components to be contained within a range that does not interfere with the function of the main component, unless otherwise specified. At this time, although the content ratio of the main component is not specified, the main component (when two or more components are the main components, the total amount thereof) is 50% by mass or more, particularly 70% by mass in the composition. % Or more, and particularly preferably 90% by mass or more (including 100% by mass).

Further, in the present invention, when expressed as "X to Y" (X, Y are arbitrary numbers), unless otherwise specified, it means "X or more and Y or less", and "preferably larger than X" and "preferably larger than X". Is smaller than Y. " Further, in the present invention, when expressed as "X or more" (X is an arbitrary number), it includes the meaning of "preferably larger than X" unless otherwise specified, and "Y or less" (Y is an arbitrary number). ) Includes the meaning of "preferably smaller than Y" unless otherwise specified.

In addition, "sheet" generally refers to a product that is thin by definition in JIS, and its thickness is generally small and flat for its length and width, and "film" generally refers to its length and width. It is a thin flat product whose thickness is extremely small and whose maximum thickness is arbitrarily limited, and is usually supplied in the form of a roll (Japanese Industrial Standard JIS K6900). For example, in terms of thickness, in a narrow sense, a film having a thickness of 100 μm or more may be referred to as a sheet, and a film having a thickness of less than 100 μm may be referred to as a film. However, since the boundary between the sheet and the film is not clear and it is not necessary to distinguish between the two in the present invention, the term "film" is used to include the "sheet" and is referred to as the "sheet" in the present invention. Even if it is, it shall include "film".

The food packaging film of the present invention has a layer A composed of a thermoplastic resin composition containing the following thermoplastic resins (I) to (III) as an essential component and a layer B containing the following (IV) thermoplastic resin as a main component. The food packaging film is composed of at least two layers, and the storage elasticity (E') at 0 to 20 ° C. measured at a vibration frequency of 10 Hz by the dynamic viscoelasticity measuring method is 100 MPa. It is preferable that the value is 1 GPa or less and the value of the loss tangent (tan δ) is 0.08 or more and 0.5 or less.
(I) At least one thermoplastic selected from propylene-ethylene copolymer, propylene-α-olefin copolymer, block polypropylene, and homopropylene having a component amount other than the propylene component of less than 6% by mass. Resin (II) Petroleum resin, terpene resin, kumaron-inden resin, rosin-based resin, and at least one thermoplastic resin selected from their hydrogenated derivatives (III) Among the following [a] to [c] At least one thermoplastic resin selected from [a] A propylene-ethylene copolymer, a propylene-α-olefin copolymer, and a propylene-ethylene-butene-1 having a component amount other than the propylene component of 6% by mass or more. Copolymer, propylene-ethylene-α-olefin copolymer [b] Copolymer consisting of a vinyl aromatic compound and a conjugated diene, and a hydrogenated derivative thereof [c] Ethylene-α olefin block copolymer weight A coalescence, an ethylene-based copolymer (IV) including an ethylene-α-olefin random copolymer, a polyamide-based resin, a polyethylene-based resin, a polypropylene-based resin, a norbornene-based resin, a polyester-based resin, an ethylene-vinyl alcohol-based copolymer, and polystyrene. At least one type of thermoplastic resin selected from the based resins

<Layer A>
The layer A of the present invention needs to be a layer made of a thermoplastic resin composition containing the predetermined thermoplastic resins (I) to (III) as essential.
In particular, by adjusting the ratio of the thermoplastic resin (II) and the thermoplastic resin (III), adhesiveness, that is, excellent adhesion to an object to be packaged such as food can be obtained.

<Thermoplastic resin (I)>
The thermoplastic resin (I) may be, for example, a homopolymer of propylene, or a propylene-based resin such as a random copolymer or a block copolymer with another monomer copolymerizable with propylene. At least one selected from a propylene-ethylene copolymer having an ethylene component content of less than 6% by mass, a propylene-α-olefin copolymer having an α-olefin component content of less than 6% by mass, block polypropylene, and homopropylene. A component composed of a kind of resin can be mentioned, and it is necessary that the component is made of at least one kind of resin selected from these.

By containing such a propylene-based resin, the cuttability at the time of packaging can be improved, and in addition to the pellet storage stability, the strength and heat resistance of the thermoplastic resin composition constituting the layer A can be enhanced. it can.

At this time, as other monomers copolymerizable with polypropylene, for example, α-olefins having 4 to 20 carbon atoms such as ethylene, 1-butene, 1-hexene, 4-methylpentene-1, 1-octene and the like. Examples thereof include dienes such as divinylbenzene, 1,4-cyclohexadiene, dicyclopentadiene, cyclooctadiene and etilidennorbornene. Further, as long as the amount of these components is less than 6% by mass, two or more of these may be copolymerized.

Examples of the propylene-based resin that can be used as the thermoplastic resin (I) include a homopolymer of propylene, a random copolymer with another monomer copolymerizable with propylene, and a block copolymer. Examples of the propylene-based resin include the product names "Novatec PP" and "WINTEC" manufactured by Nippon Polypro Co., Ltd., the product name "Noblen" manufactured by Sumitomo Chemical Co., Ltd., and the product name "Prime Polypro" manufactured by Prime Polymer Co., Ltd.

The melt flow rate (MFR) of the thermoplastic resin (I) is not particularly limited, but usually, the MFR (JISK7210, temperature: 230 ° C., load: 21.18N) is 0.2 g / 10 minutes or more. It is preferably 0.5 to 18 g / 10 minutes, and more preferably 1 to 15 g / 10 minutes. If the MFR is 0.2 g / 10 minutes or more, the extrusion processability is stable, and if it is 20 g / 10 minutes or less, stable film formation is possible at the time of molding, and thickness unevenness and mechanical strength are lowered. It is preferable because there is less variation.

The content of the thermoplastic resin (I) with respect to the total amount of the layer A is preferably 1 to 60% by mass. The lower limit of the content is more preferably 10% by mass or more, and further preferably 15% by mass or more. The upper limit of the content is preferably 50% by mass or less, and more preferably 45% by mass or less. When the content of the thermoplastic resin (I) in the layer A is 1% by mass or more, the cutability at the time of packaging can be improved, and in addition to the pellet storage stability, the resin composition constituting the layer A The strength and heat resistance can be increased, and when it is 60% by mass or less, the strength and heat resistance of the resin composition can be increased, and the adhesion to the adherend in a temperature environment from refrigeration to room temperature can be imparted. It is preferable from the viewpoint of achieving both.

<Thermoplastic resin (II)>
As the thermoplastic resin (II), for example, at least one component selected from petroleum resin, terpene resin, kumaron-inden resin, rosin-based resin, and hydrogenated derivatives thereof (hereinafter, these are collectively referred to as “”. It is necessary that the thermoplastic resin is at least one selected from "petroleum resins").

Such a thermoplastic resin (II) component can enhance the waist and cutability of the film at the time of packaging, and also effectively acts on further improvement of adhesiveness and transparency.

Here, as the petroleum resin, for example, an alicyclic petroleum resin obtained from cyclopentadiene or a dimer thereof, an aromatic petroleum resin obtained from a C9 component, or a copolymerization of an alicyclic and an aromatic petroleum resin. Examples include petroleum resins.

Examples of the terpene resin include a terpene resin obtained from β-pinene and a terpene-phenol resin.

Examples of the kumaron-indene resin include a thermoplastic synthetic resin obtained by purifying a 160 to 180 ° C. fraction of tar and polymerizing kumaron having 8 carbon atoms and indene having 9 carbon atoms as main monomers.

Examples of the rosin-based resin include rosin resins such as gum rosin and wood rosin, and esterified rosin resins modified with glycerin and pentaerythritol.

For the above petroleum resins, it is preferable to use a hydrogenated derivative from the viewpoints of color tone, thermal stability, and compatibility.

Further, the above petroleum resins can be obtained having various softening temperatures mainly depending on the molecular weight, but those having a softening temperature of 100 to 150 ° C., preferably 110 to 140 ° C. are more preferable.

Specifically, Tosoh's product name "Petcol", Tosoh's product name "Petro Tac", Arakawa Chemical Industry's product name "Arcon", Yasuhara Chemical's product name "Clearlon", Idemitsu Petrochemical Commercially available products such as the product name "Imarb" manufactured by Chemical Company and the product name "T-REZ" manufactured by JXTG Energy Co., Ltd. can be used.

The content of the thermoplastic resin (II) layer A with respect to the total amount is preferably 1 to 40% by mass. The lower limit of the content is more preferably 5% by mass or more, further preferably 10% by mass or more, and the upper limit of the content is more preferably 35% by mass or less, and 30% by mass or less. Is even more preferable. When the content is 1% by mass or more, it is preferable that the film for food packaging can be provided with the necessary elasticity and cuttability of the film at the time of packaging, and when the content is 40% by mass or less, the glass of the film is used. It is preferable because the low temperature suitability due to an increase in the transition temperature is not easily impaired, and the film is not easily blocked by bleeding of low molecular weight substances.

<Thermoplastic resin (III)>
The thermoplastic resin (III) needs to be at least one type of thermoplastic resin selected from the following [a] to [c].
[A] A propylene-ethylene copolymer, a propylene-α-olefin copolymer, a propylene-ethylene-butene-1 copolymer, a propylene-ethylene-α-, in which the amount of components other than the propylene component is 6% by mass or more. Olefin copolymer [b] Copolymer composed of a copolymer of a vinyl aromatic compound and a conjugated diene and a hydrogenated derivative thereof [c] Ethylene-α olefin block copolymer, ethylene-α olefin random copolymer Ethylene-based copolymer containing

The thermoplastic resin used as the thermoplastic resin (III) is selected from [a] to [c] from the viewpoint of compatibility with the thermoplastic resin (I) and imparting flexibility to the layer A. It needs to be at least one thermoplastic resin of choice.
These thermoplastic resin (III) components can impart flexibility by mixing with other resin components and contribute to the adhesiveness of the food packaging film of the present invention.

<Thermoplastic resin (III)-[a]>
As a propylene-based copolymer in which the content of the thermoplastic resin (III)-[a] other than the propylene component is 6% by mass or more, specifically, propylene-ethylene having an ethylene component amount of 6% by mass or more. Copolymers, propylene-α-olefin copolymers having an α-olefin component content of 6% by mass or more, propylene-ethylene-butene-1 copolymers, and propylene-ethylene-α-olefin copolymers are propylene and comonomer. It is preferably a copolymer of.
Here, as other monomers copolymerizable with polypropylene, α-olefins having 4 to 20 carbon atoms such as ethylene, 1-butene, 1-hexene, 4-methylpentene-1, 1-octene and divinyl Dienes such as benzene, 1,4-cyclohexadiene, dicyclopentadiene, cyclooctadiene, and ethylidene norbornene can be mentioned, but if the amount of these components is 6% by mass or more, two or more of these are copolymerized. It may have been.

More specifically, the product name "Wellnex" manufactured by Japan Polypropylene Corporation, the product name "Newcon" manufactured by Japan Polypropylene Corporation, the product name "Tough Serene" manufactured by Sumitomo Chemical Corporation, and the product name "Prime TPO" manufactured by Prime Polymer Co., Ltd. , Commercial products such as the trade name "Versify" manufactured by Dow Chemical Co., Ltd. can be used.

<Thermoplastic resin (III)-[b]>
As a copolymer composed of a copolymer of a vinyl aromatic compound of the thermoplastic resin (III)-[b] and a conjugated diene or a hydrogenated derivative thereof, styrene is used as the vinyl aromatic compound. Although typical, styrene homologues such as α-methylstyrene can also be used.
Examples of the conjugated diene include 1,3-butadiene, isoprene, and 1,3-pentadiene, and these can be used alone or in combination of two or more. Further, as the third component, a small amount of components other than the vinyl aromatic compound and the conjugated diene may be contained. However, when a double bond mainly composed of a vinyl bond in the conjugated diene portion remains, the thermal stability and weather resistance are extremely poor. To improve this, 80% or more, or even 95% of the double bond. It is preferable to use the one to which hydrogen is added.

Further, the ratio of the vinyl aromatic compound of such a copolymer to the conjugated diene is preferably 3/97 to 40/60 by weight. Here, when the vinyl aromatic compound in the copolymer composition is 3% by mass or more, the rigidity is not excessively lowered when it is used as a film for food packaging, and on the other hand, it is 40% by mass or less. , The effect of imparting flexibility to the film and reducing the tensile elastic modulus is sufficient without the rigidity being too high.

Specifically, the styrene-butadiene block copolymer elastomer is manufactured by Asahi Kasei Kogyo Co., Ltd. under the trade name "Tufprene", and the hydrogenated derivative of styrene-butadiene block copolymer is manufactured by Asahi Kasei Kogyo Co., Ltd. under the trade name "Tough Tech". As a hydrogenated derivative of a styrene-isoprene block copolymer, the trade name "Septon" manufactured by Kuraray Co., Ltd., and as a styrene-vinylisoprene block copolymer elastomer, a trade name "Hybler" manufactured by Kuraray Co., Ltd., etc. are commercially available. Goods can be used.

<Thermoplastic resin (III)-[c]>
Examples of the ethylene-based copolymer of the thermoplastic resin (III)-[c] include an ethylene-α-olefin block copolymer. The ethylene-α-olefin random copolymer is a copolymer of ethylene and a comonomer, and other monomers copolymerizable with polyethylene include, for example, propylene, 1-butene, 1-pentene, and 4-methyl-1-pentene. , 1-Hexene, 1-octene, 1-decene, 1-docene and the like, but if the amount of these components is 4% by mass or more, two or more of these may be copolymerized.

Specific examples thereof include the product name "Evolu" manufactured by Prime Polymer Co., Ltd., the product name "Neozex" manufactured by Prime Polymer Co., Ltd., the XLT series of "Engage" manufactured by Dow Chemical Co., Ltd., and "Infuse".

The melt flow rate (hereinafter, also referred to as “MFR”) of the thermoplastic resin (III) is not particularly limited, but usually MFR (JISK7210, temperature: 230 ° C., load: 21.18N) is 0. It is 2 g / 10 minutes or more, preferably 0.5 to 18 g / 10 minutes, and more preferably 1 to 15 g / 10 minutes. If the MFR is 0.2 g / 10 minutes or more, the extrusion processability is stable, and if it is 20 g / 10 minutes or less, stable film formation is possible at the time of molding, and thickness unevenness and mechanical strength are lowered. It is preferable because there is less variation.

The content of the thermoplastic resin (III) with respect to the total amount of the layer A is preferably, for example, 1 to 50% by mass. The upper limit of the content is more preferably 5% by mass or more, further preferably 10% by mass or more, and the lower limit of the content is more preferably 45% or less, and preferably 40% or less. More preferred. When the content is 1% by mass or more, flexibility at room temperature from 0 ° C. can be imparted, which contributes to adhesiveness to an object to be packaged such as food. Further, if it is 50% by mass or less, the rigidity and heat resistance of the thermoplastic resin composition are not impaired, and it is preferable from the viewpoint of imparting flexibility and achieving both rigidity and heat resistance.

Further, the thermoplastic resin (III) is preferably a propylene-based copolymer from the viewpoint of compatibility with the thermoplastic resin (I), and specifically, the amount of the ethylene component containing the propylene component is 6% by mass or more. A certain propylene-ethylene copolymer, a propylene-α-olefin copolymer having an α-olefin component content of 6% by mass or more, a propylene-ethylene-butene-1 copolymer, a propylene-ethylene-α-olefin copolymer Any one of the above is particularly preferable.

<Content of layer A of thermoplastic resins (I) to (III)>
As the content of the layers A of the thermoplastic resins (I) to (III), when the thermoplastic resin composition of the layer A is 100% by mass, the content of the thermoplastic resins of the (I) to (III) is However, it is preferable that (I) / (II) / (III) = 1 to 60% by mass / 1 to 40% by mass / 1 to 50% by mass, and (I) / (II) / (III) = 10. More preferably, it is ~ 60% by mass / 5 to 30% by mass / 10 to 50% by mass. By setting the content of the layer A of the thermoplastic resins (I) to (III) in the above range, the physical properties such as flexibility, rigidity, and heat resistance of the food packaging film can be appropriately adjusted, and the food packaging can be adjusted. It is also preferable in that it is easy to handle, such as imparting the waist and cutability of the film.

<Layer B>
It is necessary for the food packaging film of the present invention that the layer B of the present invention contains a predetermined thermoplastic resin (IV) as a main component. By providing this layer B with respect to the layer A, it is possible to impart functionality such as heat resistance, rigidity, strength, impact resistance, and barrier property to the food packaging film.

<Thermoplastic resin (IV)>
Examples of the thermoplastic resin (IV) include polyamide resin, polyethylene resin, polypropylene resin, norbornene resin, polyester resin, vinyl alcohol resin copolymer, ethylene-vinyl alcohol resin, polystyrene resin, and polyacrylic resin. It is necessary that the thermoplastic resin is at least one selected from the based resins.

Examples of the polyamide resin include aromatic polyamide resins, aliphatic polyamide resins, and mixtures thereof, but they are usually aliphatic in terms of heat resistance, barrier properties, and raw material cost required for food packaging films. Polyamide resin is preferably used.

Examples of the polyamide resin include hexamethylenediamine, decamethylenediamine, dodecamethylenediamine, trimethylhexamethylenediamine, 1,3- or 1,4-bis (aminomethyl) cyclohexane, bis (p-aminocyclohexylmethane), and m. -Or p-aliphatic such as xylylenediamine, alicyclic, aromatic diamine and adipic acid, suberic acid, sebacic acid, cyclohexanedicarboxylic acid, terephthalic acid, isophthalic acid and other aliphatic, alicyclic, aromatic Polyamide obtained by polycondensation with dicarboxylic acid, polyamide obtained by condensation of aminocarboxylic acid such as ε-aminocaproic acid and 11-aminoundecanoic acid, polyamide obtained from lactam such as ε-caprolactam and ε-laurolactam, or these Examples thereof include the copolymerized polyamide of.

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, Polyamide-6 / 11 and the like are preferably mentioned. From the viewpoint of moldability, a film having a melting point of 170 to 250 ° C. is preferable, and the film for food packaging may be heated in a microwave oven. Therefore, it is preferable to use polyamide 6 from the viewpoint of heat resistance.

Examples of the polyethylene-based resin include low-density polyethylene, linear low-density polyethylene, linear ultra-low-density polyethylene, medium-density polyethylene, high-density polyethylene, and copolymers containing ethylene as a main component, for example, ethylene and propylene. 3 to 3 carbon atoms of butene-1, penten-1, hexene-1, 4-methylpentene-1, heptene-1, octene-1 and the like
10 α-olefins, 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 their ionomers, conjugated diene and non-conjugated diene. Examples thereof include a copolymer or multiple copolymer with one or more comonomer selected from such unsaturated compounds, or a mixed composition thereof. The content of ethylene units in the ethylene-based polymer usually exceeds 50% by mass.

Among these ethylene-based polymers, low-density polyethylene, linear low-density polyethylene, linear ultra-low-density polyethylene, ethylene-vinyl acetate copolymer (EVA), ethylene-acrylic acid ester copolymer, ethylene-methacryl. At least one ethylene-based polymer selected from the ester copolymer and the ionomer resin is preferable.

Among these, from the viewpoint of heat resistance, linear low-density polyethylene using α-olefin selected from 1-butene, 1-hexene, and 4-methylpentene-1 as a comonomer is preferable.

Polyethylene-based resins are preferable because they have excellent mechanical properties at low temperatures and can impart cold resistance.

The polypropylene-based resin may be, for example, a propylene homopolymer, or a propylene-based resin such as a random copolymer or a block copolymer with another monomer copolymerizable with propylene, and propylene-ethylene. Examples thereof include copolymers, propylene-α-olefin copolymers, propylene-ethylene-butene-1 copolymers, propylene-ethylene-α-olefin copolymers, block polypropylene, random polypropylene, homopropylene and the like. The content of the propylene unit of the propylene-based copolymer is usually more than 50%.

Other monomers copolymerizable with polypropylene include, for example, α-olefins having 4 to 20 carbon atoms such as ethylene, 1-butene, 1-hexene, 4-methylpentene-1, 1-octene, and divinylbenzene. Dienes such as 1,4-cyclohexadiene, dicyclopentadiene, cyclooctadiene, and ethylidene norbornene can be mentioned, but two or more of these may be copolymerized.

Polypropylene resin is preferable because it can impart strength and heat resistance.

The norbornene-based resin is a resin having a norbornene skeleton, and examples thereof include a cyclic olefin polymer (COP) and a cyclic olefin copolymer (COC). Norbornene-based resins are preferable because they can impart heat resistance and moisture resistance.

Examples of the polyester-based resin are resins obtained by copolymerizing a diol component and a dicarboxylic acid component, and examples thereof include polyethylene terephthalate, polyethylene naphthalate, and glycol-modified polyethylene terephthalate. 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, and 1, , 6-Hexanediol, Cyclohexanedimethanol, Diethylene glycol, Triethylene glycol, Polyalkylene glycol, Tetramethylcyclobutanediol, 2,2-bis (4-hydroxyethoxyphenyl) propane, 4,4'-thiodiphenol, Bisphenol A 4,4'-Methylenediphenyl, 4,4'-hydroxybiphenol, dihydroxybenzene and the like can be mentioned, and only one type of these diol components may be used, or two or more types may be used in combination. .. Examples of the dicarboxylic acid component include aromatic dicarboxylic acids such as terephthalic acid, isophthalic acid, diphenylcarboxylic acid, diphenylsulfonedicarboxylic acid, diphenoxyetanedicarboxylic acid, 5-sodiumsulfoisophthalic acid, and phthalic acid, and oxalic acid. Aliphatic dicarboxylic acids such as succinic acid, ecoic acid, adipic acid, sebacic acid, dimer acid, dodecandioic acid, maleic acid and fumaric acid, alicyclic dicarboxylic acids such as cyclohexanedicarboxylic acid; trimellitic acid, pyromellitic acid, etc. Examples of the polyfunctional acid of. Only one kind of these dicarboxylic acid components may be used, or two or more kinds may be used in combination.

The polyester resin is preferable because it can impart heat resistance, gas barrier property, and impact resistance.

The ethylene-vinyl alcohol copolymer is a resin obtained by, for example, saponifying an ethylene-vinyl ester-based copolymer, which is a copolymer of ethylene and a vinyl ester-based monomer. 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 versatic acid and the like. Examples include aliphatic vinyl esters and aromatic vinyl esters such as vinyl benzoate. Usually, aliphatic vinyl esters having 3 to 20 carbon atoms can be mentioned. Normally, only one type is used, but two types are used as necessary. The above may be used together. As the vinyl ester-based monomer, vinyl acetate is used because of its marketability and high efficiency of impurity treatment during production.

The ethylene-vinyl alcohol copolymer is preferable because it has excellent gas barrier properties.

The polystyrene-based resin is a resin having a styrene structure as a part or all of a repeating unit, for example, styrene, α-methylstyrene, o-methylstyrene, p-methylstyrene, p-chlorostyrene, p-nitrostyrene, Styrene-based monomers such as p-aminostyrene, p-carboxystyrene, and p-phenylstyrene, ethylene, propylene, butadiene, isoprene, acrylonitrile, methacrylonitrile, α-chloroacrylonitrile, methyl acrylate, methyl methacrylate, Examples thereof include copolymers with other monomers such as ethyl acrylate, ethyl methacrylate, acrylate, styrene, maleic anhydride, vinyl acetate and the like. Further, polystyrene mixed with a small amount of butadiene rubber particles, so-called high impact polysthylene (HIPS), or the like can also be used.

Polystyrene-based resin is preferable because it can impart the waist and strength of the film.

<Thickness of layer A>
The thickness of the layer A of the food packaging film of the present invention is preferably 10 to 80%, more preferably 20 to 70% of the total thickness of the film. When the thickness ratio of the layer A to the total film thickness is 10% or more, the food packaging film can be imparted with adhesiveness, and when it is 80% or less, the functionality of the layer B can be exhibited. it can.

<Layer containing polyethylene resin and polyamide resin as main components>
The food packaging film of the present invention preferably has one layer containing a polyethylene resin as a main component in terms of being able to impart cold resistance and being inexpensive.
The food packaging film of the present invention preferably has high rigidity in terms of cutability and the like, and preferably has one layer containing a polyamide resin as a main component. In addition, it is possible to impart fragrance retention so that the odor of the packaged food does not leak.

The amount of heat of crystal melting (ΔHm) measured by the differential scanning calorimetry of the food packaging film of the present invention is preferably 30 J / g to 90 J / g. Further, it is more preferably 35 J / g or more, and further preferably 40 J / g or more. When the amount of heat of crystal fusion (ΔHm) is 30 J / g or more, heat resistance, mechanical strength and low water absorption are also excellent. On the other hand, if it is 90 J / g or less, transparency and flexibility can be improved. Further, the crystal melting peak temperature (Tm) of the amount of heat of crystal melting (ΔHm) is preferably 100 ° C. or higher, more preferably 110 ° C. or higher. When the crystal melting peak temperature (Tm) is 100 ° C. or higher, the film is less likely to be deformed when heated in, for example, a microwave oven.
The amount of heat of crystal melting (ΔHm) and the peak temperature of crystal melting (Tm) are measured by the methods described in Examples. When a plurality of peaks derived from the heat of crystal melting were observed, the peak with the maximum heat of crystal melting was defined as the heat of crystal melting of the food packaging film of the present invention.

According to the dynamic viscoelasticity measuring method of the food packaging film of the present invention, the storage elastic modulus (E') at 110 ° C. measured at a vibration frequency of 10 Hz is preferably 10 MPa or more, more preferably 20 MPa or more. It is more preferably 30 MPa or more. If the storage elastic modulus (E') at 110 ° C. is 10 MPa or more, the film is less likely to be deformed, for example, when the packaged food is heated in a microwave oven.

<Other ingredients>
Various additives such as the following are appropriately blended in any of the layers constituting the food packaging film of the present invention in order to impart performance such as antifogging property, antistatic property, slipperiness and adhesiveness. Can be done.

Here, as various additives, for example, an aliphatic alcohol type 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. Fatty acid esters, specifically monoglyceriolate, polyglycerin oleate, glycerin trilysinolate, glycerin acetyl lysinolate, polyglycerin stearate, glycerin laurate, polyglycerin laurate, methylacetyl lysinolate, ethyl acetyl lysinolate, Butylacetylricinolate, 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., as well as polyalkyl ethers. Polyethylene glycol, specifically polyethylene glycol, polypropylene glycol and the like, and paraffin-based oil and the like can be mentioned, and one or more of these can be used in combination.

These additives are preferably blended in an amount of 0.1 to 12 parts by mass, preferably 1 to 8 parts by mass, based on 100 parts by mass of the resin component constituting the surface layer and / or the intermediate layer.

Additives such as antioxidants, heat stabilizers, antioxidants, UV absorbers, antiblocking agents, light stabilizers, compatibilizers, and colorants, as long as they do not impair the performance of food packaging films. Can be appropriately blended.

Further, in the food packaging film of the present invention, a recycled raw material can be added to any layer as long as the effects of the present invention are not impaired. For example, the amount of trimming loss that occurs when both ends of the film-formed film are cut and trimmed, the film that was film-formed at the beginning of production immediately after the production machine that was stopped, and the products that are sold are defective. It can be prepared by adding the non-defective loss as a constituent raw material. As a result, waste of material can be eliminated and material cost can be reduced.

<Other layers>
The food packaging film of the present invention may be composed of at least two layers, layer A and layer B, but it is necessary to improve mechanical properties and interlayer adhesiveness without exceeding the gist of the present invention. Other layers may be introduced as appropriate depending on the situation.
In particular, when layers A and B are polar thermoplastic resin components and non-polar thermoplastic resin components, respectively, there is a possibility of peeling between layers, and an adhesive resin layer is provided to improve the interlayer adhesiveness. Is preferable. The thermoplastic resin constituting the adhesive resin layer is not particularly limited, but preferably contains a modified polyolefin resin having a polar group introduced therein.
By introducing another layer, it is preferable in that various functions such as barrier property, anti-fog property, and impact resistance can be imparted to the film.

<Film layer structure>
The food packaging film of the present invention may be composed of at least two layers, layer A and layer B, but if a suitable layer structure of the present invention is specified, two layers of layer A / layer B may be specified. In addition to the configuration, it is composed of two types of three-layer configurations such as layer A / layer B / layer A, layer B / layer A / layer B configuration, and at least three layers of layer A and layer B and other layers C. In the case, it is composed of three layers of layer A / layer B / layer C, three types of five layers such as layer A / layer B / layer C / layer B / layer A, and at least four layers of other layers D. If so, a four-layer configuration of layer A / layer B / layer C / layer D, a four-kind seven-layer configuration such as layer A / layer B / layer C / layer D / layer C / layer B / layer A, etc. There is no limitation on the number of layers, the order of layers, and the type and number of layers other than layers A and B.

An example of the structure of the food packaging film of the present invention is shown in FIG.
FIG. 1 is a cross-sectional view schematically showing the structure of the food packaging film according to the present embodiment. As shown in FIG. 1, in the food packaging film 10, the first layer 11 of the surface layer, the second layer 12 of the intermediate layer, the third layer 13 of the adhesive resin layer, and the fourth layer 14 of the base layer are arranged in this order 4. This is a configuration example in which the layers are laminated. Here, the first layer 11 is composed of the components of the layer B, the second layer 12 is composed of the components of the layer A, the third layer 13 is the adhesive resin component, and the fourth layer 14 is composed of the components of the layer B. ing. In the example shown in FIG. 1, the third layer 13 is provided, but as described above, this adhesive resin layer is not an essential configuration, and the first layer and the fourth layer are components of the layer B, but they are not necessarily It is not necessary to provide two layers B.

<Film thickness>
The thickness of the food packaging film of the present invention is preferably 30 μm or less, more preferably 20 μm or less. The lower limit is not limited, but is preferably 3 μm or more. When the thickness is 30 μm or less, the film has appropriate rigidity and the cutter blade has good cutability, which is preferable.

<Film manufacturing method>
The method for producing the food packaging film of the present invention will be described, but the present invention is not limited to the following production method.

First, when the constituent raw materials of each layer are mixed compositions, it is preferable to mix the constituent raw materials of each layer in advance and pelletize them as necessary. As a mixing method at this time, for example, a kneader, a Banbury mixer, a kneader such as a roll, a single-screw or twin-screw extruder may be used in advance to precompound, or the fertile material may be dry-blended. You can also put it directly into the film extruder. Further, since additives such as antioxidants and colorants are commercially available in the state of a masterbatch, they can be mixed more preferably by using them. In any of the mixing methods, it is necessary to consider deterioration due to oxidation and decomposition of the raw materials, but pre-compound is preferable for uniform mixing.

Next, the constituent raw materials can be produced by putting them into an extruder, melt-extruding them, and forming them into a film by T-die molding or inflation molding. In the case of a laminated film, it is preferable to coextrude with a multilayer die using a plurality of extruders. Practically, it is preferable to form a film by taking the melt extruded from the T-die as it is while quenching it with a casting roll or the like.

When the heat resistance and cutability of the film are important, the melt-extruded film is cooled and solidified by a cooling roll, then heated below the crystallization temperature of the resin, and the speed difference between the nip rolls is used to move the film in the vertical direction. Stretching Longitudinal stretching is preferable.

The stretching temperature depends on the constituent material of the film, but the temperature of the extruded film is preferably set in the range of 70 to 120 ° C, and more preferably in the range of 90 to 110 ° C. The draw ratio is preferably in the range of 1.2 to 5.0 times, and more preferably in the range of 1.5 to 3.0 times. When the draw ratio is in the range of 1.2 to 5.0 times, the cutability can be improved without causing troubles such as breakage and whitening of the extruded film.

The film thus obtained can be subjected to longitudinal stretching between heating rolls, various types of heat fixing, as necessary, according to the purpose of reducing the heat shrinkage rate and the natural shrinkage rate, suppressing the occurrence of width shrinkage, and the like. Heat treatment such as aging may be performed.

Further, for the purpose of imparting and promoting antifogging property, antistatic property, adhesiveness and the like, treatments such as corona treatment and aging, and surface treatments such as printing and coating and surface treatments may be performed.

The obtained film can be commercialized by trimming both ends and then slitting it to a desired width. Further, a film roll can be collected as an original roll having a winding length of 1000 m or more, then rewound into a small roll film of 100 m or less in a separate process, and boxed in a carton box with a cutter blade. When productivity and economy are important, it is desirable to separate small rewinding and boxing.

<Physical properties of film>
The storage elastic modulus (E') of the food packaging film of the present invention is stored at 0 to 20 ° C. measured at a vibration frequency of 10 Hz and a strain of 0.1% by the dynamic viscoelasticity measurement method described in the JISK-7198A method. The average value of the elastic modulus (E') needs to be in the range of 100 MPa to 1 GPa.
When the storage elastic modulus (E') is 100 MPa or more, problems such as the films sticking to each other at room temperature and the workability deteriorates are unlikely to occur.
On the other hand, when it is 1 GPa or less, the film has appropriate flexibility, and sufficient adhesiveness can be obtained when packaging an object to be packaged such as food. Each of the above physical properties is achieved by appropriately adjusting the blending ratio of the thermoplastic resin (I), the thermoplastic resin (II), and the thermoplastic resin (III), and in particular, the blending ratio of the thermoplastic resin (II) is 10. This can be achieved by making the amount of the thermoplastic resin (III) 10 to 40% by mass.

Regarding the loss tangent (tan δ) of the food packaging film of the present invention, the loss tangent at 0 to 20 ° C. measured at a vibration frequency of 10 Hz and a strain of 0.1% by the dynamic viscoelasticity measuring method described in the JISK-7198A method. The average value of (tan δ) should be in the range of 0.08 to 0.5.
When the loss tangent (tan δ) is 0.08 or more, the film has an appropriate viscosity and is less likely to be peeled off when an object to be packaged such as food is packaged.
On the other hand, in the case of 0.5 or less, the viscosity is not high enough to fuse the films, and even when the packages wrapped in the film are loaded, the problem that the packages stick to each other is less likely to occur.
Each of the above physical properties is achieved by increasing the thickness ratio of the layer A to the entire film and appropriately adjusting the blending ratios of the thermoplastic resin (I), the thermoplastic resin (II), and the thermoplastic resin (III). In particular, it can be achieved by setting the blending ratio of the thermoplastic resin (II) to 10 to 30% by mass and the thermoplastic resin (III) to 10 to 40% by mass.

The adhesive strength of the food packaging film of the present invention to glass is preferably 10 gf or more and 30 gf or less. If it is 10 gf or more, it is possible to obtain a sufficient adhesiveness when packaging an object to be packaged such as food. On the other hand, if it is 30 gf or less, the problem that the packages are stuck to each other is less likely to occur even when the packages packaged with the film are loaded. The adhesive strength to the glass is measured by the method described in Examples.

The amount of heat of crystal melting (ΔHm) measured by the differential scanning calorimetry of the food packaging film of the present invention is preferably, for example, 30 J / g to 90 J / g. It is more preferably 35 J / g or more, and further preferably 40 J / g or more. When the amount of heat of crystal fusion (ΔHm) is 30 J / g or more, heat resistance, mechanical strength and low water absorption are also excellent. On the other hand, if it is 90 J / g or less, transparency and flexibility can be improved. Further, the crystal melting peak temperature (Tm) of the amount of heat of crystal melting (ΔHm) is preferably 100 ° C. or higher, for example. When the crystal melting peak temperature (Tm) is 100 ° C. or higher, the film is less likely to be deformed when heated in, for example, a microwave oven.
The amount of heat of crystal melting (ΔHm) and the peak temperature of crystal melting (Tm) are measured by the methods described in Examples. When a plurality of peaks derived from the heat of crystal melting were observed, the peak with the maximum heat of crystal melting was defined as the heat of crystal melting of the food packaging film of the present invention.

(Delivery property)
The time required for feeding the food packaging film of the present invention is, for example, preferably less than 5 seconds, more preferably less than 3 seconds, and even more preferably less than 1 second. When the feeding time is less than 5 seconds, the film can be unwound with a light force, which is practically preferable. The payout property is measured by the method described in Examples.

(Blocking property)
The time required for feeding after the food packaging film of the present invention is rolled up and stored for one week in a temperature environment of, for example, 50 ° C. is preferably less than 50 seconds, preferably less than 40 seconds. More preferably, it is less than 30 seconds. If the time required for feeding out is 50 seconds or more, it is necessary to pull strongly when unwinding the film for use of the film after long-term storage of the film, and there is a possibility that the film will pop out of the box containing it. , Practically, it can be a problem. The payout property is measured by the method described in Examples described later.

Hereinafter, the present invention will be described in more detail with reference to Examples, but the present invention is not limited thereto. In addition, various measured values and evaluations about the film and its material shown in this specification were performed as follows. Here, the flow direction of the film from the extruder is called MD, and the direction perpendicular to the flow direction is called TD.

(1) Average value of loss tangent (tan δ) at 0 ° C to 20 ° C According to the dynamic viscoelasticity measuring method described in the JISK-7198A method, the dynamic viscoelasticity measuring device “DVA-200” manufactured by IT Measurement Control Co., Ltd. The TD of the film was measured at a vibration frequency of 10 Hz and a strain of 0.1% at a heating rate of 1 ° C./min from -100 ° C. to 200 ° C., and from the obtained data at a temperature of 0 ° C. to 20 ° C. The average value of the loss tangent (tan δ) was calculated.

(2) Adhesive strength A 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 to which this test piece is attached is subjected to a tensile tester (a product manufactured by Shimadzu Corporation) using a jig. Set at an angle of 90 ° with respect to the tensile direction of the name "Autograph AGS-J"), fix the end of the test piece to the grip part of the chuck so that the distance between the chucks is 100 mm, and the test piece is from the glass. It was peeled off at a rate of 200 mm / min until it was peeled off. The value obtained by subtracting the film weight from the maximum test force at this time was defined as the adhesive force (gf), and the average value measured three times was defined as the film adhesive force (gf).

(3) Crystal melting heat (ΔHm) and crystal melting peak temperature (Tm)
Using the brand name "DSC-7" manufactured by PerkinElmer, the measurement sample is cooled to −70 ° C. according to JISK7121 and JISK7122, and then heated to 200 ° C. at a heating rate of 10 ° C./min. After holding for 1 minute, the temperature was lowered to −70 ° C. at a temperature lowering rate of 10 ° C./min, and the temperature was measured again at a heating rate of 10 ° C./min. The crystal melting peak temperature (Tm) was determined. When a plurality of peaks derived from the heat of crystal melting were observed, the peak with the maximum heat of crystal melting was defined as the heat of crystal melting.

(4) Adhesion to the container The adhesion to the container when packaged in a bowl-shaped ceramic container having a diameter of 10 cm and a depth of 5 cm was evaluated according to the following criteria.
◯: Does not peel off from the container and maintains the shape of the container ×: Slightly peels off from the container and spreads from the shape of the container, or the film spreads without following the container

(5) Unwindability A winding body wound with a width of 300 mm on a paper tube having a diameter of 29 mm so that the weight of the paper tube and the film is 95 g is held at the end of the film, and the wound body is dropped from a height of 1.5 m. The time required for the film to fall to the floor was measured. In addition, it was measured immediately after it was made into a roll, and the payability was evaluated according to the following criteria.
◯: It takes less than 5 seconds to fall ×: It takes more than 5 seconds to fall

(6) Blocking property A winding body wound with a width of 300 mm on a paper tube having a diameter of 29 mm so that the weight of the paper tube and the film is 95 g is held at the end of the film, and the wound body is dropped from a height of 1.5 m. The time it took for the film to fall to the floor was measured. After long-term storage, it was measured after being stored as a roll in a temperature environment of 50 ° C. for 1 week, and the payability was evaluated according to the following criteria.
◯: It takes less than 50 seconds to fall ×: It takes more than 50 seconds to fall

<Example 1>
As the composition forming the layer A of Example 1, as the thermoplastic resin (I), a propylene-based resin (propylene-ethylene random copolymer (copolymer ratio: propylene component 97 wt%, ethylene component 3 wt%, melt) Florate (JISK7210, temperature: 230 ° C, load: 21.18N) 3.0 g / 10 minutes)) and hydrogenated petroleum resin (softening temperature 125 ° C, manufactured by Arakawa Chemical Industry Co., Ltd.) as the thermoplastic resin (II). Trade name "Arcon P125") and propylene-ethylene random copolymer (copolymer ratio: propylene component 92 wt%, ethylene component 8 wt%, melt flow rate (JISK7210, temperature: 230 ° C.) as the thermoplastic resin (III) , Load: 21.18N) 2g / 10 minutes) and was blended so that the mass ratio was (I) / (II) / (III) = 40/20/40, and these were melt-kneaded.

The composition for forming the layer B-1 of Example 1 is a linear low-density polyethylene containing butene-1 as a comonomer (density: 0.92 g / cm ³ , melt flow rate (JISK6922-2, temperature 190 ° C.). , Load 2.16 kg): 2.1 g / 10 minutes) (hereinafter, LLD-1) and linear low-density polyethylene using hexene-1 as a comonomer (density: 0.937 g / cm ³ , melt flow rate (hereinafter, melt flow rate) JISK7210, temperature 190 ° C., load 2.16 kg): 2.3 g / 10 minutes) (hereinafter, LLD-2) and an antifogging agent containing diglycerin oleate as a main component in a mass ratio of LLD-1 / LLD-2. / Antifogging agent = 77/20/3, and melt-kneaded.

As the composition forming the layer B-2 of Example 1, polyamide 6 “Amylan CM1021T” manufactured by Toray Industries, Inc. was selected.

As the composition for forming the adhesive layer between the layer A and the layer B-2, the trade name "Admer NF614" (hereinafter abbreviated as "ADR-1") manufactured by Mitsui Chemicals, Inc., which is an acid-modified polyethylene, is selected. , ADR-1 / LLD-1 = 20/80 in terms of mass ratio, and melt-kneaded.

Then, each layer forming composition as described above is put into a separate extruder for each layer, melt-kneaded, and then the molten resin is merged, and the layer B-1 is formed at a 7-layer T die temperature of 245 ° C. and a die gap of 1 mm. The total thickness is 7 μm (thickness ratio) by co-extruding in the order of / layer A / adhesive layer / layer B-2 / adhesive layer / layer A / layer B-1 and quenching with a cast roll set at a temperature of 30 ° C. : 7-layer food packaging film of layer B-1 / layer A / adhesive layer / layer B-2 / adhesive layer / layer A / layer B-1 = 19/17/5/18/5/17/19) Got

<Example 2>
The thickness ratio in Example 1 was changed to layer B-1 / layer A / adhesive layer / layer B-2 / adhesive layer / layer A / layer B-1 = 13/23/5/18/5/23/13. A 7-layer film was obtained in the same manner as in Example 1 except that the composition of layer B-1 was changed to LLD-1 / LLD-2 / antifogging agent = 57/40/3 by weight ratio.

<Example 3>
7 layers in the same manner as in Example 1 except that the mass ratio of the composition forming layer A in Example 1 was changed to (I) / (II) / (III) = 20/30/50. I got a film.

<Example 4>
Seven layers in the same manner as in Example 1 except that the mass ratio of the composition forming layer A in Example 1 was changed to (I) / (II) / (III) = 33/24/43. I got a film.

<Comparative example 1>
A 7-layer film was obtained in the same manner as in Example 1 except that the layer A in Example 1 was changed to LLD-1 only.

<Comparative example 2>
Layer A in Example 1 is a linear low-density polyethylene containing LLD-1 and butene-1 as comonomer (density: 0.924 g / cm ³ , melt flow rate (JISK7210, temperature 190 ° C., load 2.16 kg)). : 1.25 g / 10 minutes) (hereinafter, LLD-3) was blended so that the mass ratio was LLD-1 / LLD-3 = 90/10, and melt-kneaded.
Further, the layer B-1 is mainly composed of "Nisseki Polybutene HV100" (hereinafter abbreviated as "ADR-2") manufactured by JXTG Energy Co., Ltd. and monoglyceride acetate as an adhesive with LLD-1 and LLD-2. LLD-1 / LLD-2 / ADR-2 / release agent / antifogging agent = 66/20/10/2/2 by mass ratio of the release agent and the antifogging agent containing glycerin fatty acid ester as the main component. It was blended so as to be, and melt-kneaded. A 7-layer film was obtained in the same manner as in Example 1 except that these were changed.

<Comparative example 3>
The same as in Example 1 except that the mass ratio of the composition forming the layer A in Example 1 was changed to (I) / (II) = 77/23 and the film thickness was changed to 8 μm. A 7-layer film was obtained.

The results of Examples 1 and 2 and Comparative Examples 1 and 2 are shown in Table 1 below.

As shown in Table 1, in Example 1, as the thermoplastic resin (I), a propylene-ethylene random copolymer (copolymer ratio: propylene component 97 wt%, ethylene component 3 wt%) and a thermoplastic resin (II). ) As a hydrogenated petroleum resin and a propylene-ethylene random copolymer (copolymer ratio: propylene component 92 wt%, ethylene component 8 wt%) as a thermoplastic resin (III) in terms of mass ratio (I) / (II). ) / (III) = 40/20/40, so that the adhesive strength was as good as 12 gf, and the container adhesion, feeding property, and blocking property were also good.
Further, in Example 2, the thickness ratio in Example 1 is set to layer B-1 / layer A / adhesive layer / layer B-2 / adhesive layer / layer A / layer B-1 = 13/23/5/18 /. The composition of layer B-1 was changed to 5/23/13, and the composition of layer B-1 was changed to linear low density polyethylene (LLD-1) containing butene-1 as a comonomer and linear low density polyethylene (LLD-1) containing hexene-1 as a comonomer. By changing to density polyethylene (LLD-2) / antifogging agent = 57/40/3, the thickness ratio (%) of layer A to the entire film was increased from 36% to 46%, and the adhesive strength was increased in Examples. It increased from 12 gf of 1 to 13 gf. Further, the container adhesion, the feeding property and the blocking property were also good as in Example 1.
Further, in Example 3, the mass ratio of the composition forming the layer A in Example 1 was changed so as to be (I) / (II) / (III) = 20/30/50, but the container adhesion was changed. The payout property and the blocking property were also good as in Example 1.
In addition, in Example 4, the mass ratio of the composition forming the layer A in Example 1 was changed so as to be (I) / (II) / (III) = 33/24/43, but the container adhered to the container. The property, feeding property and blocking property were also good as in Example 1.
On the other hand, in Comparative Example 1, since only linear low-density polyethylene (LLD-1) containing butene-1 as a comonomer is used, the adhesive strength is reduced from 12 gf to 9 gf as compared with Example 1, and the container. Adhesion was poor.
Further, in Comparative Example 2, in Comparative Example 1, a linear low-density polyethylene (LLD-1) having butene-1 as a comonomer and a linear low-density polyethylene having butene-1 as a comonomer as layer A (hereinafter, hereinafter, LLD-3) is changed to LLD-1 / LLD-3 = 90/10 in terms of mass ratio, and even when a pressure-sensitive adhesive and a release agent are added in layer B-1, the adhesive strength remains. Although it was improved as compared with Comparative Example 1 (11 gf), it was found that the feeding property was poor, the blocking property was lowered, and there was a problem in long-term storage.
In addition, in Comparative Example 3, the mass ratio of the composition forming the layer A in Example 1 was changed so as to be (I) / (II) = 77/23, but the thermoplastic resin of (III) was used. Since it was not contained, the flexibility of the film was impaired and the container adhesion was poor. From the above, the effect of the present invention is clear.

10 Food packaging film 11 1st layer 12 2nd layer 13 3rd layer 14 4th layer

Claims (9)

Food packaging consisting of at least two layers, a layer A composed of a thermoplastic resin composition containing the following thermoplastic resins (I) to (III) as an essential component, and a layer B containing the following (IV) thermoplastic resin as a main component. It is a film for
The storage elastic modulus (E') at 0 to 20 ° C. measured at a vibration frequency of 10 Hz by the dynamic viscoelasticity measuring method of the food packaging film is 100 MPa or more and 1 GPa or less, and the value of loss tangent (tan δ). A film for food packaging having a value of 0.08 or more and 0.5 or less.
(I) At least one thermoplastic selected from propylene-ethylene copolymer, propylene-α-olefin copolymer, block polypropylene, and homopropylene having a component amount other than the propylene component of less than 6% by mass. Resin (II) Petroleum resin, terpene resin, kumaron-inden resin, rosin-based resin, and at least one thermoplastic resin selected from their hydrogenated derivatives (III) Among the following [a] to [c] At least one thermoplastic resin selected from [a] A propylene-ethylene copolymer, a propylene-α-olefin copolymer, and a propylene-ethylene-butene-1 having a component amount other than the propylene component of 6% by mass or more. Copolymer, propylene-ethylene-α-olefin copolymer [b] Copolymer consisting of a vinyl aromatic compound and a conjugated diene, and a hydrogenated derivative thereof [c] Ethylene-α olefin block copolymer weight A coalescence, an ethylene-based copolymer (IV) including an ethylene-α-olefin random copolymer, a polyamide-based resin, a polyethylene-based resin, a polypropylene-based resin, a norbornene-based resin, a polyester-based resin, an ethylene-vinyl alcohol-based copolymer, and polystyrene. At least one type of thermoplastic resin selected from the based resins When the thermoplastic resin composition of the layer A is 100% by mass, the content of the thermoplastic resin of (I) to (III) is (I) / (II) / (III) = 1 to 60% by mass. A film for food packaging, which is% / 1-40% by mass / 1-50% by mass. The food packaging film according to claim 1 or 2, wherein the thickness of the layer A is 10% or more and 80% or less of the total thickness of the food packaging film. The food packaging film according to any one of claims 1 to 3.
Further, a film for food packaging having one or more layers containing a polyethylene resin as a main component. The food packaging film according to any one of claims 1 to 4.
Further, a film for food packaging having one or more layers containing a polyamide resin as a main component. The food packaging film according to any one of claims 1 to 5.
A film for food packaging, wherein the heat of crystal melting (ΔHm) in the differential scanning calorimetry is 30 J / g to 90 J / g, and the peak temperature of crystal melting (Tm) is 100 ° C. or higher. The food packaging film according to any one of claims 1 to 6.
A film for food packaging having a storage elastic modulus (E') of 10 MPa or more at 110 ° C. measured at a vibration frequency of 10 Hz by a dynamic viscoelasticity measuring method. The food packaging film according to any one of claims 1 to 7, wherein the total thickness is 30 μm or less. A small roll film for food packaging in which the food packaging film according to any one of claims 1 to 8 is stored in a carton box with a cutter blade.

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