JP2022139179A - Film for deep-draw packaging, deep-draw package, polyolefin resin film, and method for producing film for deep-draw packaging - Google Patents

Abstract

To provide a film for deep-draw packaging having excellent impact resistance, deep-drawability, and recyclability.SOLUTION: A film for deep-draw packaging has at least three resin layers of an outer layer, an intermediate layer, and an inner layer, and satisfies the following conditions (1)-(3). (1) A resin composition forming the outer layer and the inner layer is primarily composed of a polyolefin resin. (2) A resin composition forming the intermediate layer is primarily composed of a copolymer of propylene and ethylene or a mixture of polypropylene resin and polyethylene resin. (3) An ethylene content is 2 mass% or more and 50 mass% or less relative to 100 mass% of the resin composition forming the intermediate layer.SELECTED DRAWING: None

Description

TECHNICAL FIELD The present invention relates to a deep-drawn packaging film, a deep-drawn package, a polyolefin resin film, and a method for producing a deep-drawn packaging film.

Deep-drawing packaging film is a well-known technology mainly in the fields of food packaging and medical packaging. The opening is covered with a film or non-woven fabric called a lid material, and the periphery is adhered or welded to the container. Conventionally, the bottom material of deep-drawn packaging film includes a seal layer that imparts heat-sealing properties with the lid material, an ethylene-vinyl alcohol resin layer that imparts gas barrier properties, and a polyamide layer that imparts impact resistance and deep drawability. It is common to use a multilayer film in which various resins are laminated such as layers (see, for example, Patent Document 1).

On the other hand, in recent years, the demand for recycling plastic products has increased due to their environmental impact. As a method for recycling multilayer films, a technique is disclosed in which film pieces discharged during manufacturing are returned to some of the polyolefin layers (see, for example, Patent Document 2).

JP 2006-224470 A JP 2016-087892 A

However, when a multi-layer film containing a polyamide resin is blended with a polyolefin layer, the decrease in transparency is remarkable. Therefore, it is necessary to prevent the addition of recycled raw materials from being increased and to make the layer containing recycled raw materials thinner. There is a problem that the recycling rate is low.

Accordingly, an object of the present invention is to provide a deep-drawn packaging film excellent in impact resistance, deep-drawing formability, and recyclability, and a package using the same.

The inventors of the present invention have made intensive studies in view of the above-mentioned circumstances, and found that the outer layer and inner layer of a deep-drawn packaging film are formed from a resin composition containing a polyolefin resin as a main component, and the intermediate layer is formed from a specific polyolefin resin. By forming from a resin composition having a resin as the main component and having a specific amount of ethylene content, it has equivalent impact resistance and deep drawability even when no polyamide resin is used, and recyclability. The present inventors have found that they are excellent in , and have completed the present invention.

That is, the gist of the present invention is the following [1] to [9].
[1] A deep-drawn packaging film comprising at least three resin layers, an outer layer, an intermediate layer and an inner layer, which satisfies the following (1) to (3).
(1) The resin composition forming the outer layer and the inner layer contains a polyolefin resin as a main component. (2) The resin composition forming the intermediate layer is a copolymer of propylene and ethylene, or a polypropylene resin and polyethylene. (3) When the resin composition forming the intermediate layer is 100% by mass, the ethylene content is 2% by mass or more and 50% by mass or less [2] The deep-drawn packaging film The film for deep-drawing packaging according to [1], wherein the resin composition forming all the resin layers constituting the contains a polyolefin-based resin as a main component.
[3] The deep-drawn packaging film according to [1] or [2], further comprising at least four resin layers having a gas barrier layer.
[4] The deep drawing packaging film according to [3], wherein the resin composition forming the gas barrier layer contains an ethylene-vinyl alcohol-based resin as a main component.
[5] The deep-drawn packaging film according to any one of [1] to [4], wherein one of the resin layers contains a recycled raw material obtained from the deep-drawn packaging film.
[6] The deep-drawn packaging film according to any one of [1] to [5], wherein the deep-drawn packaging film has an internal haze of 30% or less.
[7] A deep-drawn package using the deep-drawn packaging film according to any one of [1] to [6] as a bottom material.
[8] A polyolefin-based resin film containing a recycled raw material made from the deep-drawn packaging film according to any one of [1] to [6].
[9] A method for producing a deep-drawn packaging film comprising at least three resin layers, an outer layer, an intermediate layer, and an inner layer, comprising a step of producing a recycled raw material using the deep-drawn packaging film as a starting material, Co-extrusion of a resin composition containing recycled raw materials to obtain a deep-drawn packaging film comprising at least three resin layers, ie, an outer layer, an intermediate layer and an inner layer.

According to the present invention, it is possible to provide a deep-drawn packaging film that is excellent in impact resistance, deep-drawing formability, and recyclability.

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, embodiments of the present invention will be described in detail. However, the contents of the present invention are not limited to the embodiments described below.

In the present specification, the term "main component" refers to a component that accounts for the most mass% when the total of the object is 100% by mass, preferably 50% by mass or more, and 60% by mass or more. More preferably, 70% by mass or more is even more preferable.

In addition, when described as “X to Y” (X and Y are arbitrary numbers), unless otherwise specified, “X or more and Y or less”, “preferably larger than X” and “preferably smaller than Y” ” is included.

In the present specification, the term "film" is meant to include thick sheets to thin films.

In addition, the upper limit and lower limit of the numerical range in this specification, even if slightly deviating from the numerical range specified by the present invention, as long as it has the same effect as within the numerical range, the present invention shall be included in the equivalent range of

The deep-drawn packaging film of the present invention comprises at least three resin layers, an outer layer, an intermediate layer and an inner layer, and satisfies the following (1) to (3).
(1) The resin composition forming the outer layer and the inner layer contains a polyolefin resin as a main component. (2) The resin composition forming the intermediate layer is a copolymer of propylene and ethylene, or a polypropylene resin and polyethylene. (3) When the resin composition forming the intermediate layer is taken as 100% by mass, the ethylene content is 2% by mass or more and 50% by mass or less Each layer will be described below.

<Outer layer>
The outer layer is a layer that becomes the outer side of the deep-drawn package, and the resin composition forming the outer layer contains a polyolefin resin as a main component.

Examples of the polyolefin resins include polyethylene resins, polypropylene resins, α-olefin copolymers, and resins obtained by modifying these polyolefin resins. These may be used alone or in combination of two or more. The polyolefin resin used in the outer layer excludes the resin composition having a specific ethylene content used in the intermediate layer described later.

Examples of the polyethylene-based resin include linear low-density polyethylene (LLDPE), low-density polyethylene (LDPE), medium-density polyethylene (MDPE), high-density polyethylene (HDPE), and the like.

Examples of the polypropylene-based resin include random polypropylene (rPP), block polypropylene (bPP), homopolypropylene (hPP), and the like.

Examples of the α-olefin copolymers include copolymers of α-olefins such as ethylene, 1-butene, 1-pentene, 1-hexene, 4-methyl-1-pentene and 1-octene. Specific examples include ethylene-α-olefin copolymers, propylene-α-olefin copolymers, ethylene-propylene-α-olefin copolymers, and the like.

Among the polyolefin resins, polyethylene resins and α-olefin copolymers are preferable from the viewpoint of pinhole resistance, polypropylene resins are preferable from the viewpoint of imparting heat resistance, and random polypropylene resins are preferable from the viewpoint of moldability. is more preferred.

Further, the resin obtained by modifying the polyolefin resin is an adhesive resin used for the purpose of imparting adhesion between the outer layer and the adjacent layer, and the modifying component includes unsaturated carboxylic acid or a derivative thereof. mentioned.

Examples of the unsaturated carboxylic acid include acrylic acid, methacrylic acid, maleic acid, fumaric acid, crotonic acid, itaconic acid, citraconic acid, and esters and anhydrides thereof.
Examples of the derivatives include methyl acrylate, methyl methacrylate, ethyl acrylate, propyl acrylate, butyl acrylate, butyl methacrylate, glycidyl acrylate, glycidyl methacrylate, acrylamide, methacrylamide, sodium acrylate, etc. Derivatives to which vinyl acetate and the like are added can be mentioned.

The melt flow rate (MFR) of the polyolefin resin (JIS K7210-1 A method (2014), 230° C., load 2.16 kg) is 0.1 g/10 min or more and 50 g/10 min or less from the viewpoint of film formability. is preferred, and 1 g/10 min or more and 40 g/10 min or less is more preferred.

The melting point of the polyolefin resin is preferably 95° C. or higher and 175° C. or lower, more preferably 100° C. or higher and 170° C. or lower, even more preferably 115° C. or higher and 168° C. or lower. By making the melting point equal to or higher than the above lower limit, sticking to a hot plate during deep drawing can be suppressed, and heat resistance during boiling treatment can be imparted. Furthermore, when used for retort applications, the temperature is preferably 115°C or higher. By setting the melting point to 175° C. or less, deep drawability can be imparted.

The storage elastic modulus E′ of the polyolefin resin measured at a vibration frequency of 10 Hz and 90° C. is preferably 1.0×10 ⁶ Pa or more and 8.0×10 ⁸ Pa or less, and 1.5× It is more preferably 10 ⁶ Pa or more and 5.0×10 ⁸ Pa or less, and particularly preferably 2.0×10 ⁶ Pa or more and 4.0×10 ⁸ Pa or less. By setting the storage elastic modulus E′ at 90° C. within the above range, stretchability and stiffness can be imparted during deep drawing, and local thinning due to stretching unevenness can be prevented.

In addition, the storage modulus E′ of the polyolefin resin measured at a vibration frequency of 10 Hz and −20° C. is preferably 5.0×10 ⁹ Pa or less, and 4.5×10 ⁹ Pa or less. It is more preferably 4.0×10 ⁹ Pa or less. Low-temperature impact resistance can be imparted by setting the storage elastic modulus E′ at −20° C. to the above value or less. The lower limit of the storage modulus E' at -20°C is usually 1.0 x ^107Pa .

As described above, the resin composition forming the outer layer contains a polyolefin resin as a main component, and the content thereof is preferably 50% by mass or more, preferably 70% by mass or more, of the resin composition. is more preferable.

In addition, when the resin composition forming the outer layer contains a resin (adhesive resin) obtained by modifying the polyolefin resin, the content thereof is preferably 40% by mass or less of the resin composition, and 30% by mass. % or less.

The thickness of the outer layer of the deep-drawn packaging film of the present invention is preferably 5 μm or more and 100 μm or less, more preferably 7 μm or more and 80 μm or less, and even more preferably 10 μm or more and 60 μm or less. By setting the thickness of the outer layer within the above range, film-forming stability and deep drawability can be imparted.

<Middle layer>
The intermediate layer of the deep-drawn packaging film of the present invention contains a copolymer of propylene and ethylene or a mixture of a polypropylene-based resin and a polyethylene-based resin as a main component, and is formed from a resin composition having a specific ethylene content. be done.

Conventionally, polyamide-based resins having excellent impact resistance and deep drawability have been used as intermediate layers of deep-drawn packaging films. However, when a deep-drawn packaging film or deep-drawn package using a polyamide resin as an intermediate layer is used as a recycled raw material and mixed with a polyolefin resin, the polyamide resin has poor compatibility with the polyolefin resin and is transparent. It was difficult to increase the recycling rate due to the remarkably reduced performance.
On the other hand, in the present invention, by using a copolymer of propylene and ethylene or a mixture of a polypropylene resin and a polyethylene resin instead of the polyamide resin, impact resistance equivalent to that of the polyamide resin, deep drawing molding It is possible to increase the recycling rate while having the characteristics.

As the copolymer of propylene and ethylene, a random copolymer and a block copolymer are preferable.
In the copolymer of propylene and ethylene, the α-olefin component in addition to propylene and ethylene is usually 40% by mass or less, preferably 30% by mass or less, more preferably 30% by mass or less, based on the copolymer of propylene and ethylene. may contain 25% by mass or less. Examples of the α-olefin include 1-butene, 1-pentene, 1-hexene, 4-methyl-1-pentene, 1-octene and the like. These may be used alone or in combination of two or more. Among them, 1-butene is preferred. Commercially available products of the copolymer of propylene and ethylene include, for example, Tafmer PN (manufactured by Mitsui Chemicals, Inc.).

Examples of the mixture of the polypropylene-based resin and the polyethylene-based resin include a mixture obtained by blending the polypropylene-based resin with ethylene propylene rubber (EPR). As the EPR, those kneaded while being copolymerized with a polypropylene-based resin by multi-stage polymerization are preferable because the EPR is finely dispersed in the mixture, and the impact resistance tends to be further improved.

The propylene content in the copolymer of propylene and ethylene or the mixture of the polypropylene-based resin and the polyethylene-based resin is preferably 50% by mass or more and 98% by mass or less, more preferably 55% by mass or more and 97% by mass or less, 60% by mass or more and 95% by mass or less is more preferable. By setting the propylene content to the above value or more, it is possible to maintain the melting point and elastic modulus during heating and impart deep drawability. By setting the propylene content to the above value or less, impact resistance at low temperatures can be imparted.

The melt flow rate (MFR) (JIS K7210-1 A method (2014), 230 ° C., load 2.16 kg) of the copolymer of propylene and ethylene or the mixture of polypropylene resin and polyethylene resin is From the viewpoint of film properties, it is preferably 0.1 g/10 min or more and 50 g/10 min or less, more preferably 0.3 g/10 min or more and 20 g/10 min or less.

The melting point of the copolymer of propylene and ethylene or the mixture of polypropylene-based resin and polyethylene-based resin is preferably 120° C. or higher and 180° C. or lower, more preferably 125° C. or higher and 175° C. or lower, from the viewpoint of deep drawing moldability. 128° C. or higher and 170° C. or lower is more preferable.

The glass transition temperature of the copolymer of propylene and ethylene or the mixture of polypropylene resin and polyethylene resin is preferably 20° C. or lower, more preferably 15° C. or lower, and still more preferably 10° C. or lower. Low-temperature impact resistance can be imparted by setting the glass transition temperature to the above numerical value or less. Although there is no particular lower limit for the glass transition temperature, it is usually −100° C., preferably −70° C. because it is a general-purpose product and is readily available.

The storage elastic modulus E' of the copolymer of propylene and ethylene or the mixture of polypropylene resin and polyethylene resin measured at a vibration frequency of 10 Hz and at 90° C. is 1.0×10 ⁶ Pa or more. It is preferably 0×10 ⁹ Pa or less, more preferably 1.5×10 ⁶ Pa or more and 9.0×10 ⁸ Pa or less, and 2.0×10 ⁶ Pa or more and 8.0×10 ⁸ Pa. The following are particularly preferred. By setting the storage elastic modulus E′ at 90° C. within the above range, stretchability and stiffness can be imparted during deep drawing, and local thinning due to stretching unevenness can be prevented.

The storage elastic modulus E' of the copolymer of propylene and ethylene or the mixture of polypropylene resin and polyethylene resin measured at a vibration frequency of 10 Hz and -20°C is 2.0 × 10 ⁹ Pa. It is preferably 1.5×10 ⁹ Pa or less, more preferably 1.5×10 9 Pa or less, and even more preferably 1.0×10 ⁹ Pa or less. Low-temperature impact resistance can be imparted by setting the storage elastic modulus E′ at −20° C. to the above value or less. The lower limit of the storage modulus E' at -20°C is usually 1.0 x ^107Pa .

The resin composition forming the intermediate layer contains the propylene-ethylene copolymer or the mixture of the polypropylene-based resin and the polyethylene-based resin as a main component, and the content thereof is such that the low-temperature impact resistance is maintained. In view of the above, the content of the resin composition is preferably 60% by mass or more, more preferably 65% by mass or more. Further, the copolymer of propylene and ethylene or the mixture of the polypropylene-based resin and the polyethylene-based resin may be used as a mixture by using two or more kinds thereof. More than one type of copolymer of propylene and ethylene may be used.

In the present invention, when the total mass of the resin composition forming the intermediate layer is 100% by mass, the ethylene content must be 2% by mass or more and 50% by mass or less, preferably 3% by mass. % or more and 35 mass % or less, and particularly preferably 4 mass % or more and 20 mass % or less. By setting the ethylene content of the resin composition forming the intermediate layer within the above range, deep drawability can be imparted.

For the purpose of improving deep drawability, the resin composition forming the intermediate layer of the present invention may contain, for example, additives such as a crystal nucleating agent and an antioxidant, the copolymer of propylene and ethylene, or the polypropylene-based A polypropylene-based resin other than a mixture of a resin and a polyethylene-based resin may also be included, and these may be used alone or in combination of two or more. As the polypropylene-based resin, block polypropylene and homopolypropylene are preferable, and homopolypropylene is particularly preferable.

The thickness of the intermediate layer of the deep-drawn packaging film of the present invention is usually 10 μm to 100 μm, preferably 15 μm to 80 μm, more preferably 20 μm to 60 μm. By setting the thickness of the intermediate layer within the above range, film-forming stability, impact resistance, and deep drawability can be imparted.

<Inner layer>
The deep-drawn packaging film of the present invention has an inner layer formed from a resin composition containing a polyolefin resin as a main component. Since polyolefin-based resins have heat-sealing properties, the inner layer formed from a resin composition containing polyolefin-based resin as a main component also has a function as a heat-sealing layer. Further, the inner layer is a layer that comes into contact with the contents when combined with the lid member to form a deep-drawn package, and is preferably a heat-sealable layer that has heat-sealing properties with the lid member.

Examples of the polyolefin-based resin include the copolymer of propylene and ethylene and the mixture of polypropylene-based resin and polyethylene-based resin. ), linear low-density polyethylene (LLDPE), ethylene-acrylic acid copolymer (EAA), ethylene-methyl acrylate copolymer (EMA), ethylene-ethyl acrylate copolymer (EEA), ethylene-methacryl Acid copolymer (EMAA), ethylene-methyl methacrylate copolymer (EMMA), ionomer resin, ethylene-vinyl acetate copolymer (EVA) having a vinyl acetate content of 8 mol% or more and 40 mol% or less, hot melt Examples include resins (HM) and resins obtained by modifying these polyolefin resins. Examples of the resin obtained by modifying the polyolefin-based resin include those described for the polyolefin-based resin of the outer layer. These may be used alone or in combination of two or more.
The polyolefin resin is appropriately selected according to the shape of the deep-drawn package and the shape and type of contents. In addition, the polyolefin resin may be blended in a known formulation in order to impart easy peelability. Examples of known formulations for imparting the easy peel property include mixtures in which low-density polyethylene and polybutene resin are mixed.

The melting point of the polyolefin resin is usually 100° C. or higher and 175° C. or lower, preferably 110° C. or higher and 170° C. or lower, and more preferably 115° C. or higher and 168° C. or lower. By setting the melting point within the above range, excellent heat-sealing properties can be imparted.

The resin composition forming the inner layer contains the polyolefin resin as a main component, and the content thereof is preferably 50% by mass or more, more preferably 70% by mass or more.

The thickness of the inner layer of the deep-drawn packaging film of the present invention is preferably 5 μm or more and 100 μm or less, more preferably 7 μm or more and 80 μm or less, and even more preferably 10 μm or more and 60 μm or less. By setting the thickness of the inner layer within the above range, film-forming stability and sufficient sealing properties can be imparted.

The deep-drawn packaging film of the present invention comprises at least three resin layers, ie, the outer layer, the intermediate layer, and the inner layer. You may have Further, two or more layers of these gas barrier layer, adhesive layer, adjacent layer, etc. may be present in the deep-drawn packaging film.

[Gas barrier layer]
From the viewpoint of gas barrier properties, the deep-drawn packaging film of the present invention is preferably a film comprising at least four resin layers each having a gas barrier layer. From the viewpoint of gas barrier properties, the gas barrier layer is preferably provided between the intermediate layer and the inner layer.

The gas barrier layer is a polyolefin resin obtained by saponifying a copolymer of ethylene and vinyl acetate with an alkali catalyst or the like. ) as a main component.

The ethylene content in the EVOH is not particularly limited, but is usually 23 mol% or more, preferably 25 mol% or more from the viewpoint of film forming stability, and is usually 47 mol% from the viewpoint of gas barrier properties. % or less, preferably 44 mol % or less.
The degree of saponification of EVOH is usually 96 mol% or more, preferably 99 mol% or more.
Good gas barrier properties can be maintained by keeping the ethylene content and saponification degree in the EVOH within the above ranges. EVOH is not limited to those produced by saponification as long as they have the same chemical structure.

Although the melting point of the EVOH is not particularly limited, it is usually 150° C. or higher and 210° C. or lower, preferably 150° C. or higher and 205° C. or lower, more preferably 155° C. or higher and 200° C. or lower, from the viewpoint of deep drawability. be.

The MFR (210° C., load 2.16 kg) of the EVOH is not particularly limited, but from the viewpoint of film formability, it is 0.1 to 80 g/10 min, preferably 0.5 to 50 g/10 minutes, more preferably 1.0 to 25 g/10 minutes.

The thickness of the gas barrier layer is usually 3 μm or more and 30 μm or less, preferably 4 μm or more and 25 μm or less, and more preferably 5 μm or more and 20 μm or less. By setting the thickness of the gas barrier layer within the above range, film-forming stability and sufficient gas barrier properties can be imparted, and deterioration in impact resistance and deep drawability can be suppressed.

[Adhesion layer]
The adhesive layer is arranged for the purpose of improving adhesiveness between layers, and is formed of a resin composition containing an adhesive resin as a main component. As the adhesive resin, a resin obtained by modifying the polyolefin resin described in the outer layer can be used. Moreover, the adhesive resin may be used alone or in combination of two or more.

The thickness of the adhesive layer is usually 3 μm or more and 30 μm or less, preferably 4 μm or more and 25 μm or less, and particularly preferably 5 μm or more and 20 μm or less. By setting the thickness of the adhesive layer within the above range, film-forming stability and sufficient adhesiveness can be imparted. The thickness of the adhesive layer is the total thickness of all adhesive layers of the deep-drawn packaging film.

[Adjacent layer]
The adjacent layer is arranged to improve film strength and heat resistance and to adjust thickness, and is formed from a resin composition containing a polyolefin resin as a main component.

As the polyolefin-based resin, the polyolefin-based resin described in the outer layer can be used. The polyolefin-based resins may be used alone or in combination of two or more. Moreover, the polyolefin-based resin used in the adjacent layer may be the same as or different from the polyolefin-based resin used in the outer layer.

The thickness of the adjacent layer is usually 3 μm or more and 30 μm or less, preferably 4 μm or more and 25 μm or less, and particularly preferably 5 μm or more and 20 μm or less. Film forming stability can be imparted by setting the thickness of the adjacent layer within the above range. The thickness of the adjacent layer is the total thickness of all adjacent layers of the deep-drawn packaging film.

Further, in the present invention, the resin composition forming each resin layer includes the deep-drawn packaging film of the present invention, the deep-drawn package, offcuts generated in the manufacturing process, other resin films, molded articles, etc. It is also preferable to contain recycled raw materials used as raw materials.
Although the other resin films and molded articles are not particularly limited, resin films and molded articles containing polyolefin-based resin as a main component are preferable from the viewpoint of recyclability. Above all, from the point of view of recyclability and transparency, any resin layer may contain a recycled raw material obtained from the raw material of the deep-drawn packaging film or the deep-drawn packaging body of the present invention, or offcuts generated in the manufacturing process. More preferably, any one of the resin layers contains a recycled raw material using the film for deep-drawing packaging of the present invention as a starting material.

As the recycled raw material, the film, the package, etc. may be used as they are, or the film, the package, etc. may be fluffed, repelleted, or the like. Among them, from the viewpoint of workability, fluffing and repelleting are preferable.

The "fluff" is obtained by pulverizing a film, and the "repellet" is obtained by melt-kneading a film, a package, or the like and processing it into pellets.

When the resin composition forming each resin layer contains the recycled raw material, the recycled raw material may be contained in any of the resin layers. It is preferably contained in the resin composition forming the outer layer, the adhesive layer, or the adjacent layer from the viewpoint of maintaining transparency, gas barrier properties, and the like. Among others, it is more preferably contained in the resin composition forming the adhesive layer and the adjacent layer, and particularly preferably contained in the resin composition forming the adjacent layer.

When the resin composition forming each resin layer contains the recycled raw material, the content thereof is usually 40% by mass or less, preferably 30% by mass or less, based on the resin composition.

In addition, the resin composition forming each layer of the deep-drawn packaging film of the present invention may be appropriately added with a , Inorganic particles such as silica, talc, kaolin, calcium carbonate, pigments such as titanium oxide and carbon black, flame retardants, weather stabilizers, heat stabilizers, antistatic agents, melt viscosity improvers, cross-linking agents, lubricants, nuclei Additives such as agents, plasticizers, and anti-aging agents may be added. These can be used alone or in combination of two or more.

In the deep-drawn packaging film of the present invention, the resin composition forming all the resin layers constituting the deep-drawn packaging film excluding the adhesive layer contains a polyolefin resin as a main component, from the viewpoint of recyclability. preferable. Moreover, it is preferable that the deep-drawn packaging film of the present invention does not contain a polyamide-based resin.

[Method for producing deep-drawn packaging film]
The deep-drawn packaging film of the present invention can be produced using the resin composition by known methods such as extrusion lamination, co-extrusion inflation, and co-extrusion T-die method. In particular, it is preferable to use the co-extrusion T-die method because the film-forming process does not change even when the number of layers of the film is large and the thickness control is relatively easy. That is, the deep-drawn packaging film of the present invention is preferably a coextruded multilayer film.
Further, the deep-drawn packaging film of the present invention may be a non-stretched film or a stretched film, but is usually non-stretched.

Examples of the structure of the deep-drawn packaging film of the present invention are shown below, but the present invention is not limited thereto.
(1) LLDPE (outer layer)/intermediate layer/inner layer (2) LLDPE (outer layer)/adhesive layer/intermediate layer/inner layer (3) LLDPE (outer layer)/adhesive layer/intermediate layer/adhesive layer/inner layer (4) LLDPE ( outer layer)/adhesive layer/intermediate layer/adhesive layer/LLDPE (adjacent layer)/inner layer (5) LLDPE (outer layer)/adjacent layer/adhesive layer/intermediate layer/adhesive layer/LLDPE (adjacent layer)/inner layer (6) LLDPE (outer layer)/adjacent layer/adhesive layer/intermediate layer/adhesive layer/adjacent layer/inner layer (7) rPP (outer layer)/intermediate layer/inner layer (8) rPP (outer layer)/adhesive layer/intermediate layer/inner layer (9) rPP (outer layer)/adhesive layer/middle layer/adhesive layer/inner layer (10) LDPE (outer layer)/middle layer/inner layer (11) HDPE (outer layer)/middle layer/inner layer (12) bPP (outer layer)/middle layer/ Inner layer (13) hPP (outer layer)/intermediate layer/inner layer (14) LLDPE (outer layer)/intermediate layer/adhesive layer/gas barrier layer/adhesive layer/inner layer (15) LLDPE (outer layer)/adjacent layer/intermediate layer/adhesive layer /gas barrier layer/adhesion layer/inner layer (16) LLDPE (outer layer)/intermediate layer/adhesion layer/gas barrier layer/adhesion layer/adjacent layer/inner layer (17) rPP (outer layer)/intermediate layer/adhesion layer/gas barrier layer/adhesion Layer/inner layer (18) rPP (outer layer)/adjacent layer/intermediate layer/adhesive layer/gas barrier layer/adhesive layer/inner layer (19) rPP (outer layer)/intermediate layer/adhesive layer/gas barrier layer/adhesive layer/adjacent layer/ inner layer

Further, when the deep-drawn packaging film of the present invention has a resin layer formed from a resin composition containing a recycled raw material using the deep-drawn packaging film as a starting material, the deep-drawn packaging film is the deep-drawn A step of producing a recycled raw material using a packaging film as a starting material, and co-extrusion of a resin composition containing the recycled raw material to obtain a deep-drawn packaging film comprising at least three resin layers: an outer layer, an intermediate layer, and an inner layer. obtained by a manufacturing method comprising the steps of:

Examples of the recycled raw material in the step of producing a recycled raw material using the deep-drawn packaging film as a starting material include fluff and repellets obtained from the deep-drawn packaging film.

In addition, as a method for obtaining fluff and repellets from the deep-drawn packaging film, known methods, for example, cutting treatment, pulverization treatment, drying treatment, melt-kneading treatment, etc. can be performed on the deep-drawn packaging film. can be done. These treatments may be performed singly or in combination of two or more.

In the step of co-extruding the resin composition containing the recycled raw material to obtain a deep-drawn packaging film comprising at least three resin layers of an outer layer, an intermediate layer, and an inner layer, the recycled raw material is obtained from the deep-drawn packaging film A resin composition containing fluff or repellets may be co-extruded with another resin composition to produce a deep-drawn packaging film. Further, as described above, the resin composition containing the recycled raw material may form any resin layer of the film for deep-drawing packaging, but preferably forms the adjacent layer and the adhesive layer, and forms the adjacent layer. is particularly preferred.

<Deep drawn packaging film>
The deep-drawn packaging film of the present invention thus obtained comprises at least three resin layers: an outer layer, an intermediate layer and an inner layer.

The thickness of the deep-drawn packaging film of the present invention is preferably 50 µm or more and less than 300 µm, more preferably 60 µm or more and less than 250 µm, even more preferably 70 µm or more and less than 200 µm. By setting the thickness to 50 μm or more, it becomes possible to obtain deep drawing formability and a practically acceptable thickness after deep drawing, and it is possible to impart mechanical strength and heat resistance. By setting the thickness to less than 300 μm, it is possible to impart deep drawability and reduce costs.

The internal haze value calculated from the total light transmittance and diffuse transmittance measured based on JIS K7136 (2000) of the deep-drawn packaging film of the present invention is preferably 30% or less from the viewpoint of visibility of the contents. 25% or less is more preferable, and 20% or less is even more preferable.

The puncture energy of the deep-drawn packaging film of the present invention by a Hydroshot high-speed tester at 23 ° C. measured according to JIS K7124-2 (1999) is preferably 0.50 J or more, and 0.60 J or more. more preferred. Moreover, the amount of puncture displacement is preferably 10 mm or more, more preferably 15 mm or more. By setting the puncture energy at 23° C. and the amount of puncture displacement within the above ranges, there is a tendency that breakage and pinholes are less likely to occur due to impacts that occur during packaging and transportation of the contents, for example.

The puncture energy of the deep-drawn packaging film of the present invention by a Hydroshot high-speed tester at 5 ° C. measured according to JIS K7124-2 (1999) is preferably 0.50 J or more, and 0.60 J or more. more preferred. The puncture displacement amount is preferably 10 mm or more, more preferably 12 mm or more. By setting the puncture energy at 5° C. and the amount of puncture displacement within the above ranges, pinholes tend to be less likely to occur even when the contents are packaged and stored at a low temperature such as refrigerated storage.

The puncture energy of the deep-drawn packaging film of the present invention by a Hydroshot high-speed tester at -20 ° C. measured according to JIS K7124-2 (1999) is preferably 0.35 J or more, and 0.4 J or more. is more preferred. Moreover, the amount of puncture displacement is preferably 5 mm or more, more preferably 7 mm or more. By setting the puncture energy and the amount of puncture displacement at −20° C. within the above ranges, pinholes tend to be less likely to occur even when the contents are packaged and stored at a low temperature such as frozen storage.

In addition, when the deep-drawn packaging film of the present invention has a gas barrier layer, the gas permeability when the deep-drawn packaging film has a thickness of 100 μm is preferably 10.0 cc/m ² · 24 hr · atm or less, and more It is preferably 8.5 cc/m ² ·24 hr·atm or less, more preferably 7.0 cc/m ² ·24 hr·atm or less. By setting the gas permeability to 10.0 cc/m ² ·24 hr·atm or less, there is a tendency that the gas barrier property required when used as a package can be imparted.

The deep-drawn packaging film of the present invention can be used not only as a recycled raw material for the deep-drawn packaging film, but also as a resin using a recycled raw material using the deep-drawn packaging film as a starting material when producing other resin films. A film (resin layer) may be produced.
Although the other resin film is not particularly limited, it is preferably a resin film containing a polyolefin resin as a main component because it has high compatibility and can increase the recycling rate.

<Package>
The deep-drawn packaging film of the present invention is suitable for deep-drawn packaging, and can be made into various packaging depending on the contents. Examples of packages are shown below.
(1) Deep-drawn package (2) Pouch package (3) Pillow package (4) Vacuum package Among them, a deep-drawn package is preferable, and particularly preferably, the deep-drawn packaging film is used as a bottom material. It is a deep-drawn package.

When the deep-drawn packaging film of the present invention is to be formed into a deep-drawn package, it is preferably produced without drawing in order to improve the formability during the drawing process. For pouch packaging, pillow packaging, and vacuum packaging, after manufacturing without stretching, from the viewpoint of imparting strength and gas barrier properties, stretched films such as biaxially stretched polypropylene films are used, for example, and laminated by dry lamination. preferably.

Hereinafter, the present invention will be described in more detail based on examples carried out to clarify the effects of the present invention. The present invention is by no means limited by the following examples and comparative examples.

Raw materials used for the outer layer, middle layer, inner layer, and other layers (adhesive layer, gas barrier layer, etc.) are shown below.
PE1: ULTZEX 3520L (LLDPE manufactured by Prime Polymer Co., Ltd.)
PE2: Admer NF567 (manufactured by Mitsui Chemicals, PE adhesive resin)
PE3: ULTZEX 2021L (LLDPE manufactured by Prime Polymer Co., Ltd.)
PE4: Yumerit 2040FC (manufactured by Ube Maruzen Polyethylene Co., Ltd., LLDPE)
rPP: Prime Polypro F-724NPC (rPP, manufactured by Prime Polymer Co., Ltd.)
PP1: Toughmer PN3560 (manufactured by Mitsui Chemicals, propylene-ethylene-1-butene copolymer, propylene content 74% by mass, ethylene content 5% by mass, α-olefin content 21% by mass)
PP2: Adflex Q200F (manufactured by SunAllomer, propylene and EPR mixture, propylene content 83% by mass, ethylene content 17% by mass)
PP3: Novatec PP FY4 (manufactured by Japan Polypropylene Corporation, hPP, propylene content 100% by mass)
PP4: Admer Q551 (manufactured by Mitsui Chemicals, maleic anhydride-modified PP, propylene content 78% by mass, ethylene content 21% by mass, α-olefin content 1% by mass)
EVOH: Soarnol DC3203RB (manufactured by Mitsubishi Chemical Corporation, EVOH with an ethylene content of 32 mol%, MFR 3.8 g/10 min (210°C), melting point 183°C)
PA: UBE nylon 1030B (manufactured by Ube Industries, PA6)

The MFR, melting point, and storage modulus E' of PE1 to PE4 and rPP were measured by the following methods. The physical properties of PE1-PE4 and rPP are shown in Table 1 below.
Further, the MFR, glass transition temperature, melting point, and storage elastic modulus E' of PP1 to PP4 were measured by the following methods. The physical properties of PP1 to PP4 are shown in Table 2 below.

(MFR)
The MFR of each raw material was measured under conditions of a temperature of 230° C. and a load of 2.16 kg according to JIS K7210-1 A method (2014).

(melting point and glass transition temperature)
In accordance with JIS K7121 (2012), using a differential scanning calorimeter (PerkinElmer, "DSC8000"), each raw material was heated at 10 ° C./min to determine the melting point (Tm) and glass transition temperature ( Tg) was measured.

(Storage modulus E')
According to JIS K7244-10 (2005), a rheometer (manufactured by TA Instruments, "Discovery HR2") was used to measure the storage modulus E' at 90°C and -20°C in a tensile mode at a vibration frequency of 10Hz.

<Examples 1 to 6 and Comparative Example 1>
Each raw material was melt-kneaded at 220° C. with the composition and layer structure shown in Table 3 below, and extruded through a lamination die at 230° C. to produce a deep-drawn packaging film having a thickness of 100 μm.

<Reference example>
Each raw material was melt-kneaded at 250° C. with the composition and layer structure shown in Table 3 below, and extruded through a lamination die at 250° C. to produce a 100 μm-thick deep-drawn packaging film.

〔evaluation〕
The deep-drawn packaging films of Examples 1 to 6 and Comparative Example 1 were evaluated for impact resistance, transparency, deep drawability, recyclability, and gas barrier properties. The results are shown in Table 3 below.

(shock resistance)
A deep-drawn packaging film is punctured by a method according to JIS K7124-2 (1999) at a speed of 3 m / sec, a height of 200 mm, a striker of φ12.7 mm, and a test atmosphere temperature of 23 ° C., 5 ° C., and -20 ° C. Energy and puncture displacement were measured and evaluated according to the following criteria.
[Evaluation criteria for test atmosphere temperature of 23 ° C.]
○: Puncture energy is 0.5 J or more and the amount of puncture displacement is 10 mm or more △: Puncture energy is 0.2 J or more and less than 0.5 J and the amount of puncture displacement is 10 mm or more ×: Puncture energy is less than 0.2 J, or puncture displacement amount is less than 10 mm [Evaluation criteria for test atmosphere temperature 5 ° C.]
○: Puncture energy is 0.5 J or more and the amount of puncture displacement is 10 mm or more △: Puncture energy is 0.2 J or more and less than 0.5 J and the amount of puncture displacement is 10 mm or more ×: Puncture energy is less than 0.2 J, or puncture displacement amount is less than 10 mm [Evaluation criteria for test atmosphere temperature -20 ° C.]
○: Puncture energy is 0.5 J or more and the amount of puncture displacement is 5 mm or more △: Puncture energy is 0.2 J or more and less than 0.5 J and the amount of puncture displacement is 5 mm or more ×: Puncture energy is less than 0.2J or puncture displacement is less than 5mm

(transparency)
Using a turbidity meter (manufactured by Nippon Denshoku Industries Co., Ltd., "NDH 5000"), the surface of the deep-drawn packaging film is irradiated with light, and the haze is measured according to JIS K7136 (2000). Evaluated by
[Evaluation criteria]
○: internal haze is 30% or less ×: internal haze exceeds 30%

(Deep drawing formability)
Using a deep drawing packaging machine (FV6300 manufactured by Omori Machinery Co., Ltd.), deep drawing is performed into a cylinder with a diameter of 98 mm and a drawing depth of 30 mm under the conditions of a molding heating temperature of 95 ° C, a molding heating time of 2 seconds, and a molding time of 2 seconds. Then, the corner thickness at the position where the circumference of the bottom is divided into 4 equal parts (dividing the circumference into 4 equal parts with any point on the circumference as the base point) is measured in μm, and the minimum value of the corner thickness is was evaluated according to the following criteria.
[Evaluation criteria (thickness)]
○: corner thickness is 10 μm or more ×: corner thickness is less than 10 μm

(recyclability)
60% by mass of PE2 and 40% by mass of each of the deep-drawn packaging films of Examples 1 to 6 and Comparative Example 1 were melt-kneaded at 240° C. and extruded to produce a recycled film having a thickness of 100 μm. The transparency of the produced recycled film was evaluated in the same manner as the deep-drawn packaging film, and evaluated according to the following criteria.
[Evaluation criteria]
○: internal haze is less than 40% ×: internal haze is 40% or more

(Gas barrier property)
For the multilayer film produced, using an oxygen transmission rate measuring device (OX-Tran2/21: manufactured by MOCON), the oxygen transmission rate (cc/ m ² ·24 hr·atm) was measured and evaluated according to the following criteria.
○: 10.0 cc/m ² · 24 hr · atm or less ×: More than 10.0 cc / m ² · 24 hr · atm

The deep-drawn packaging films of Examples 1 to 6 not only have excellent impact resistance, but also have good transparency when recycled and added to the polyolefin resin. In comparison, it was possible to suppress thinning of the corners during deep drawing.

According to the deep-drawn packaging film of the present invention, it is possible to provide a deep-drawn packaging film excellent in impact resistance, deep-drawing moldability, and recyclability, and a package using the same.

Claims (9)

A deep-drawn packaging film comprising at least three resin layers, an outer layer, an intermediate layer, and an inner layer, which satisfies the following (1) to (3).
(1) The resin composition forming the outer layer and the inner layer contains a polyolefin resin as a main component. (2) The resin composition forming the intermediate layer is a copolymer of propylene and ethylene, or a polypropylene resin and polyethylene. (3) ethylene content is 2% by mass or more and 50% by mass or less when the resin composition forming the intermediate layer is taken as 100% by mass. 2. The deep-drawn packaging film according to claim 1, wherein a resin composition forming all resin layers constituting said deep-drawn packaging film contains a polyolefin resin as a main component. 3. The deep drawing packaging film according to claim 1, further comprising at least four resin layers having a gas barrier layer. 4. The deep-drawing packaging film according to claim 3, wherein the resin composition forming the gas barrier layer contains an ethylene-vinyl alcohol-based resin as a main component. The deep-drawn packaging film according to any one of claims 1 to 4, wherein one of the resin layers contains a recycled raw material obtained from the deep-drawn packaging film as a starting material. The deep-drawn packaging film according to any one of claims 1 to 5, wherein the deep-drawn packaging film has an internal haze of 30% or less. A deep-drawn package using the deep-drawn packaging film according to any one of claims 1 to 6 as a bottom material. A polyolefin-based resin film containing a recycled raw material obtained by using the deep-drawn packaging film according to any one of claims 1 to 6 as a starting material. A method for producing a deep-drawn packaging film comprising at least three resin layers, an outer layer, an intermediate layer, and an inner layer, comprising: producing a recycled raw material using the deep-drawn packaging film as a starting material; and co-extrusion of the resin composition containing the resin composition to obtain a deep-drawn packaging film comprising at least three resin layers, ie, an outer layer, an intermediate layer, and an inner layer.