Deep drawing packaging film, deep drawing package, polyolefin resin film, and method for manufacturing deep drawing packaging film

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]

[0001] The present invention relates to a deep drawing packaging film, a deep drawing package, a polyolefin resin film, and a method for producing a deep drawing packaging film. [Background technology]

[0002] Deep drawing packaging film is a well-known technology mainly in the fields of food packaging and medical packaging, and is a packaging method in which the contents are placed in a base material formed by hot forming a film to form one or more containers (cavities), the opening is covered with a film or nonwoven fabric called a lid material, and the periphery is adhered or welded to the container. Conventionally, the base material of deep drawing packaging film generally uses a multilayer film in which various resins are laminated, such as a seal layer that imparts heat sealing properties to the lid material, an ethylene vinyl alcohol resin layer that imparts gas barrier properties, and a polyamide layer that imparts impact resistance and deep drawing formability (see, for example, Patent Document 1).

[0003] On the other hand, in recent years, there has been an increasing demand for recycling plastic products due to their impact on the environment. As a method for recycling multi-layer films, a technology has been disclosed in which film pieces discharged during production are returned to some of the polyolefin layers (see, for example, Patent Document 2). [Prior art documents] [Patent documents]

[0004] [Patent Document 1] JP 2006-224470 A [Patent Document 2] JP 2016-087892 A Summary of the Invention [Problem to be solved by the invention]

[0005] However, when a multilayer film containing a polyamide resin is blended with a polyolefin layer, the transparency is significantly reduced, making it impossible to increase the amount of recycled raw materials added and making it necessary to thin the layer containing recycled raw materials, resulting in a problem of a low recycling rate.

[0006] Therefore, an object of the present invention is to provide a deep-draw packaging film that is excellent in impact resistance, deep-draw formability, and recyclability, and a package using the same. [Means for solving the problem]

[0007] In light of the above-mentioned circumstances, the inventors conducted intensive research and discovered that by forming the outer and inner layers of a deep-draw packaging film from a resin composition containing a polyolefin-based resin as its main component, and further forming the intermediate layer from a resin composition having a specific polyolefin-based resin as its main component and a specific amount of ethylene content, it is possible to obtain the same impact resistance and deep-draw formability as those obtained without using a polyamide-based resin, and also to achieve excellent recyclability, thereby completing the present invention.

[0008] That is, the gist of the present invention is the following [1] to [9]. [1] A deep drawing packaging film consisting of 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 contains, as a main component, a copolymer of propylene and ethylene or a mixture of a polypropylene-based resin and a polyethylene-based resin. (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. [2] The deep drawing packaging film described in [1], wherein the resin composition forming all of the resin layers constituting the deep drawing packaging film contains a polyolefin resin as the main component. [3] The deep drawing packaging film according to [1] or [2], which further comprises 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] A deep drawing packaging film according to any one of [1] to [4], wherein one of the resin layers contains recycled materials made from the deep drawing packaging film as a starting material. [6] The deep drawing packaging film according to any one of [1] to [5], wherein the internal haze of the deep drawing packaging film is 30% or less. [7] A deep drawing package using the deep drawing packaging film according to any one of [1] to [6] as a base material. [8] A polyolefin resin film containing recycled materials obtained by using the deep drawing packaging film according to any one of [1] to [6] as a starting material. [9] A method for producing a deep-drawn packaging film consisting of at least three resin layers: an outer layer, an intermediate layer, and an inner layer, comprising the steps of: preparing a recycled raw material using the deep-drawn packaging film as a starting material; and co-extruding a resin composition containing the recycled raw material to obtain a deep-drawn packaging film consisting of at least three resin layers: an outer layer, an intermediate layer, and an inner layer. Effect of the Invention

[0009] According to the present invention, it is possible to provide a deep drawing packaging film that is excellent in impact resistance, deep drawing formability, and further in recyclability. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0010] Hereinafter, an embodiment of the present invention will be described in detail. However, the content of the present invention is not limited to the embodiment described below.

[0011] In this specification, the term "major component" refers to a component that occupies the largest mass% when the total of the target substance is 100 mass%, and is preferably 50 mass% or more, more preferably 60 mass% or more, and even more preferably 70 mass% or more.

[0012] Furthermore, when it is written "X to Y" (X and Y are any numbers), unless otherwise specified, it includes the meaning of "X or more and Y or less", as well as "preferably greater than X" and "preferably smaller than Y".

[0013] In this specification, the term "film" is intended to encompass a wide range of materials from thick sheets to thin films.

[0014] Furthermore, even if the upper and lower limits of the numerical ranges in this specification are slightly outside the numerical ranges specified by the present invention, they are included in the equivalent range of the present invention as long as they have the same action and effect as those within the numerical range.

[0015] The deep drawing packaging film of the present invention comprises at least three resin layers, that is, 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 contains, as a main component, a copolymer of propylene and ethylene or a mixture of a polypropylene-based resin and a polyethylene-based resin. (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.

[0016] <Outer layer> The outer layer is a layer that becomes the outside when the deep-draw package is made, and the resin composition that forms the outer layer contains a polyolefin resin as a main component.

[0017] Examples of the polyolefin resin include polyethylene resin, polypropylene resin, α-olefin copolymer, and modified resins of these polyolefin resins. These may be used alone or in combination of two or more. The polyolefin resin used in the outer layer does not include the resin composition having a specific ethylene content used in the intermediate layer described later.

[0018] Examples of the polyethylene resin include linear low density polyethylene (LLDPE), low density polyethylene (LDPE), medium density polyethylene (MDPE), and high density polyethylene (HDPE).

[0019] Examples of the polypropylene resin include random polypropylene (rPP), block polypropylene (bPP), and homopolypropylene (hPP).

[0020] Examples of the α-olefin copolymer include copolymers of α-olefins such as ethylene, 1-butene, 1-pentene, 1-hexene, 4-methyl-1-pentene, 1-octene, etc. Specific examples include ethylene-α-olefin copolymers, propylene-α-olefin copolymers, ethylene-propylene-α-olefin copolymers, etc.

[0021] Among the polyolefin-based resins, polyethylene-based resins and α-olefin copolymers are preferred in terms of pinhole resistance, polypropylene-based resins are preferred in terms of imparting heat resistance, and random polypropylene is more preferred in terms of moldability.

[0022] The resin obtained by modifying the polyolefin resin is an adhesive resin used for the purpose of imparting adhesion between an outer layer and an adjacent layer, and examples of the modifying component include unsaturated carboxylic acids or derivatives thereof.

[0023] Examples of the unsaturated carboxylic acid include acrylic acid, methacrylic acid, maleic acid, fumaric acid, crotonic acid, itaconic acid, citraconic acid, and the like, as well as 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, and derivatives with vinyl acetate or the like added thereto.

[0024] The melt flow rate (MFR) of the polyolefin resin (JIS K7210-1 Method A (2014), 230°C, load 2.16 kg) is preferably 0.1 g / 10 min or more and 50 g / 10 min or less, more preferably 1 g / 10 min or more and 40 g / 10 min or less, from the viewpoint of film-forming properties.

[0025] The melting point of the polyolefin resin is preferably 95°C or more and 175°C or less, more preferably 100°C or more and 170°C or less, and even more preferably 115°C or more and 168°C or less. By setting the melting point to the lower limit or more, it is possible to suppress the sticking to the hot plate during deep drawing and to impart heat resistance during boiling treatment. Furthermore, when used for retort applications, it is preferably 115°C or more. By setting the melting point to 175°C or less, it is possible to impart deep drawing formability.

[0026] The storage modulus E' of the polyolefin resin measured at a vibration frequency of 10 Hz and at 90°C is 1.0 x 10 6 Pa or more 8.0×10 8 Pa or less, and 1.5×10 6 Pa or more 5.0×10 8 Pa or less, and more preferably 2.0×10 6 Pa or more 4.0×10 8 It is particularly preferable that the storage modulus E' at 90°C is in the above range, so that stretchability and stiffness can be imparted during deep drawing, and localized thinning due to uneven stretching can be prevented.

[0027] The storage modulus E' of the polyolefin resin measured at a vibration frequency of 10 Hz and at -20°C is 5.0 × 10 9 Pa or less, and 4.5×10 9 Pa or less, and more preferably 4.0×10 9 It is more preferable that the storage modulus E' at -20°C is equal to or less than the above-mentioned value. By setting the storage modulus E' at -20°C to be equal to or less than the above-mentioned value, low-temperature impact resistance can be imparted. The lower limit of the storage modulus E' at -20°C is usually 1.0 x 10 7 It is Pa.

[0028] 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, and more preferably 70% by mass or more, of the resin composition.

[0029] Furthermore, when the resin composition forming the outer layer contains a resin (adhesive resin) obtained by modifying the polyolefin-based resin, the content thereof is preferably 40 mass % or less, and more preferably 30 mass % or less, of the resin composition.

[0030] The thickness of the outer layer of the deep drawing packaging film of the present invention is preferably 5 μm to 100 μm, more preferably 7 μm to 80 μm, and even more preferably 10 μm to 60 μm. By setting the thickness of the outer layer in the above range, film formation stability and deep drawing formability can be imparted.

[0031] <Middle Class> The intermediate layer of the deep drawing packaging film of the present invention is formed from a resin composition containing, as a main component, a copolymer of propylene and ethylene or a mixture of a polypropylene-based resin and a polyethylene-based resin and having a specific ethylene content.

[0032] Conventionally, polyamide resins having excellent impact resistance and deep drawing formability have been used as the intermediate layer of deep drawing packaging films. However, when deep drawing packaging films or deep drawing packaging bodies using polyamide resins as the intermediate layer are mixed with polyolefin resins as recycled raw materials, the polyamide resins have poor compatibility with polyolefin resins and the transparency is significantly reduced, making it difficult to increase the recycling rate. 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 a polyamide resin, it is possible to increase the recycling rate while maintaining the same impact resistance and deep drawability as polyamide resins.

[0033] The copolymer of propylene and ethylene is preferably a random copolymer or a block copolymer. The propylene-ethylene copolymer may contain an α-olefin component in addition to propylene and ethylene, usually at 40% by mass or less, preferably 30% by mass or less, more preferably 25% by mass or less, based on the propylene-ethylene copolymer. Examples of the α-olefin include 1-butene, 1-pentene, 1-hexene, 4-methyl-1-pentene, and 1-octene. These may be used alone or in combination of two or more. Among them, 1-butene is preferred. Examples of commercially available products of the propylene-ethylene copolymer include Tafmer PN (manufactured by Mitsui Chemicals, Inc.).

[0034] The mixture of polypropylene resin and polyethylene resin may be, for example, a mixture of polypropylene resin and ethylene propylene rubber (EPR). As for EPR, it is preferable that EPR is kneaded while copolymerizing with polypropylene resin by multi-stage polymerization, since EPR is finely dispersed in the mixture, which tends to improve impact resistance.

[0035] The propylene content in the copolymer of propylene and ethylene or the mixture of polypropylene-based resin and 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, and even more preferably 60% by mass or more and 95% by mass or less. By making the propylene content equal to or more than the above numerical value, it is possible to maintain the melting point and the elastic modulus during heating and to impart deep drawability. By making the propylene content equal to or less than the above numerical value, it is possible to impart impact resistance at low temperatures.

[0036] The melt flow rate (MFR) (JIS K7210-1 Method A (2014), 230°C, load 2.16 kg) of the copolymer of propylene and ethylene or the mixture of polypropylene-based resin and polyethylene-based resin is preferably 0.1 g / 10 min or more and 50 g / 10 min or less, and more preferably 0.3 g / 10 min or more and 20 g / 10 min or less, from the viewpoint of film-forming properties.

[0037] 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, and even more preferably 128°C or higher and 170°C or lower, from the viewpoint of deep draw formability.

[0038] The glass transition temperature of the copolymer of propylene and ethylene or the mixture of polypropylene-based resin and polyethylene-based resin is preferably 20° C. or lower, more preferably 15° C. or lower, and even more preferably 10° C. or lower. By setting the glass transition temperature to the above-mentioned value or lower, low-temperature impact resistance can be imparted. There is no particular lower limit for the glass transition temperature, but it is usually −100° C., and preferably −70° C., in view of the ease of availability as a general-purpose product.

[0039] The storage modulus E' of the copolymer of propylene and ethylene or the mixture of polypropylene-based resin and polyethylene-based resin measured under conditions of a vibration frequency of 10 Hz and 90°C is 1.0 × 10 6 Pa or more 1.0×10 9 Pa or less, and 1.5×10 6Pa or more 9.0×10 8 Pa or less, and more preferably 2.0×10 6 Pa or more 8.0×10 8 It is particularly preferable that the storage modulus E' at 90°C is in the above range, so that stretchability and stiffness can be imparted during deep drawing, and localized thinning due to uneven drawing can be prevented.

[0040] The storage modulus E' of the copolymer of propylene and ethylene or the mixture of polypropylene-based resin and polyethylene-based resin measured under conditions of a vibration frequency of 10 Hz and -20°C is 2.0 × 10 9 Pa or less, and 1.5×10 9 Pa or less, and more preferably 1.0×10 9 It is more preferable that the storage modulus E' at -20°C is equal to or less than the above-mentioned value. By setting the storage modulus E' at -20°C to be equal to or less than the above-mentioned value, low-temperature impact resistance can be imparted. The lower limit of the storage modulus E' at -20°C is usually 1.0 x 10 7 It is Pa.

[0041] The resin composition forming the intermediate layer contains the copolymer of propylene and ethylene or a mixture of a polypropylene resin and a polyethylene resin as a main component, and the content is preferably 60% by mass or more, more preferably 65% ​​by mass or more, of the resin composition in terms of maintaining low-temperature impact resistance. In addition, the copolymer of propylene and ethylene or the mixture of a polypropylene resin and a polyethylene resin may be a mixture of two or more kinds of them, for example, two or more kinds of propylene and ethylene copolymers having different ethylene contents may be used as the copolymer of propylene and ethylene.

[0042] In the present invention, when the total mass of the resin composition forming the intermediate layer is taken as 100 mass%, the ethylene content must be 2 mass% or more and 50 mass% or less, preferably 3 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.

[0043] The resin composition forming the intermediate layer of the present invention may contain, for example, additives such as a crystal nucleating agent or an antioxidant, or a polypropylene-based resin other than the copolymer of propylene and ethylene or the mixture of a polypropylene-based resin and a polyethylene-based resin, for the purpose of improving deep drawing formability, and these may be used alone or in combination of two or more kinds. As the polypropylene-based resin, block polypropylene and homopolypropylene are preferred, and homopolypropylene is particularly preferred.

[0044] The thickness of the intermediate layer of the deep drawing packaging film of the present invention is usually 10 μm to 100 μm, preferably 15 μm to 80 μm, and more preferably 20 μm to 60 μm. By setting the thickness of the intermediate layer in the above range, film formation stability, impact resistance, and deep drawing formability can be imparted.

[0045] <Inner layer> The deep drawing packaging film of the present invention has an inner layer formed from a resin composition containing a polyolefin resin as a main component. Since the polyolefin resin has heat sealing properties, the inner layer formed from the resin composition containing a polyolefin resin as a main component also functions as a heat sealing layer. Moreover, the inner layer is a layer that comes into contact with the contents when combined with a lid material to form a deep drawing package, and is preferably a heat sealing layer that has heat sealing properties with the lid material.

[0046] The polyolefin resin is not limited to the above-mentioned copolymer of propylene and ethylene, and the mixture of polypropylene resin and polyethylene resin. For example, ethylene-α-olefin copolymer, low density polyethylene (LDPE), linear low density polyethylene (LLDPE), ethylene-acrylic acid copolymer (EAA), ethylene-methyl acrylate copolymer (EMA), ethylene-ethyl acrylate copolymer (EEA), ethylene-methacrylic acid copolymer (EMAA), ethylene-methyl methacrylate copolymer (EMMA), ionomer resin, ethylene-vinyl acetate copolymer (EVA) having a vinyl acetate content of 8 mol% to 40 mol%, hot melt resin (HM), and resins modified from these polyolefin resins. The resins modified from the polyolefin resin include those described in the polyolefin 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 the contents. The polyolefin resin may be blended in a known composition to impart easy peeling properties. Examples of known compositions to impart easy peeling properties include a mixture of low-density polyethylene and polybutene resin.

[0047] The melting point of the polyolefin resin is usually 100° C. or more and 175° C. or less, preferably 110° C. or more and 170° C. or less, and more preferably 115° C. or more and 168° C. or less. By setting the melting point within the above range, excellent heat sealability can be imparted.

[0048] 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, and more preferably 70% by mass or more.

[0049] The thickness of the inner layer of the deep drawing packaging film of the present invention is preferably 5 μm to 100 μm, more preferably 7 μm to 80 μm, and even more preferably 10 μm to 60 μm. By setting the thickness of the inner layer within the above range, film formation stability and sufficient sealability can be imparted.

[0050] The deep drawing packaging film of the present invention is composed of at least three resin layers, namely the outer layer, intermediate layer, and inner layer, and may further include a gas barrier layer, an adhesive layer, an adjacent layer, etc. The deep drawing packaging film may include two or more of these gas barrier layers, adhesive layers, adjacent layers, etc.

[0051] [Gas barrier layer] From the viewpoint of gas barrier properties, the deep drawing packaging film of the present invention is preferably a film consisting of at least four resin layers having a gas barrier layer. Also, from the viewpoint of gas barrier properties, it is preferable that the gas barrier layer is provided between the intermediate layer and the inner layer.

[0052] The gas barrier layer is preferably formed from a resin composition containing, as a main component, an ethylene-vinyl alcohol resin (hereinafter, sometimes referred to as "EVOH"), which is a polyolefin resin obtained by saponifying a copolymer of ethylene and vinyl acetate with an alkali catalyst or the like.

[0053] The ethylene content in the EVOH is not particularly limited, but from the viewpoint of film formation stability, it is usually 23 mol% or more, and preferably 25 mol% or more, and from the viewpoint of gas barrier properties, it is usually 47 mol% or less, and preferably 44 mol% or less. The saponification degree of EVOH is usually 96 mol % or more, and preferably 99 mol % or more. By keeping the ethylene content and saponification degree in the EVOH within the above ranges, good gas barrier properties can be maintained. Note that the EVOH is not limited to those produced by saponification, as long as they have a similar chemical structure.

[0054] The melting point of the EVOH is not particularly limited, but from the viewpoint of deep draw formability, it is usually 150° C. or more and 210° C. or less, preferably 150° C. or more and 205° C. or less, and more preferably 155° C. or more and 200° C. or less.

[0055] 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 min, and more preferably 1.0 to 25 g / 10 min.

[0056] The thickness of the gas barrier layer is usually 3 μm to 30 μm, preferably 4 μm to 25 μm, and more preferably 5 μm to 20 μm. By setting the thickness of the gas barrier layer within the above range, film formation stability and sufficient gas barrier properties can be imparted, and deterioration of impact resistance and deep draw formability can be suppressed.

[0057] [Adhesive layer] The adhesive layer is arranged for the purpose of improving the adhesion between the layers, and is formed from a resin composition containing an adhesive resin as a main component. The adhesive resin may be a resin obtained by modifying a polyolefin resin as described in the outer layer. The adhesive resin may be used alone or in combination of two or more kinds.

[0058] 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 formation stability and sufficient adhesiveness can be imparted. The thickness of the adhesive layer is the total thickness of all adhesive layers that the deep drawing packaging film has.

[0059] Adjacent Layer The adjacent layer is disposed for the purpose of improving the film strength and heat resistance and adjusting the thickness, and is formed from a resin composition containing a polyolefin resin as a main component.

[0060] The polyolefin resin may be the polyolefin resin described in the outer layer. The polyolefin resin may be used alone or in combination of two or more. The polyolefin resin used in the adjacent layer may be the same as or different from the polyolefin resin used in the outer layer.

[0061] 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. By setting the thickness of the adjacent layer within the above range, film formation stability can be imparted. The thickness of the adjacent layer is the total thickness of all adjacent layers that the deep drawing packaging film has.

[0062] In addition, in the present invention, it is also preferable that the resin composition forming each resin layer contains recycled raw materials made from the deep drawn packaging film, deep drawn packaging body, and scraps generated during the manufacturing process of the present invention, other resin films, molded bodies, etc. The other resin film and molded body are not particularly limited, but from the viewpoint of recyclability, a resin film and molded body containing a polyolefin resin as a main component is preferable. Among them, from the viewpoint of recyclability and transparency, it is more preferable that the deep drawing packaging film or deep drawing packaging body of the present invention contains a recycled raw material made from scraps generated during the manufacturing process as a starting raw material in any of the resin layers, and it is particularly preferable that the deep drawing packaging film of the present invention contains a recycled raw material made from the deep drawing packaging film as a starting raw material in any of the resin layers.

[0063] As the recycled raw material, the film, packaging, etc. may be used as it is, or the film, packaging, etc. may be used after being processed into fluff, repellet, etc. Among them, from the viewpoint of workability, it is preferable to use the film, packaging, etc. after being processed into fluff or repellet.

[0064] The "fluff" is made by crushing a film, and the "repellet" is made by melt-kneading a film or a package and processing it into a pellet shape.

[0065] When the resin composition forming each of the resin layers contains the recycled raw material, the recycled raw material may be contained in any of the resin layers, but it is preferable that the recycled raw material is contained in the resin composition forming the outer layer, adhesive layer, or adjacent layer in order to maintain the impact resistance, deep drawability, sealability, transparency, gas barrier properties, etc. of the film. In particular, it is more preferable that the recycled raw material is contained in the resin composition forming the adhesive layer or adjacent layer, and it is particularly preferable that the recycled raw material is contained in the resin composition forming the adjacent layer.

[0066] When the resin composition forming each resin layer contains the recycled raw material, the content thereof is usually 40% by mass or less, and preferably 30% by mass or less, of the resin composition.

[0067] Furthermore, the resin composition forming each layer of the deep drawing packaging film of the present invention may be appropriately blended with additives such as inorganic particles such as silica, talc, kaolin, calcium carbonate, pigments such as titanium oxide and carbon black, flame retardants, weather resistance stabilizers, heat resistance stabilizers, antistatic agents, melt viscosity improvers, crosslinking agents, lubricants, nucleating agents, plasticizers, antioxidants, etc., for the purpose of improving or adjusting various properties such as moldability and productivity, within a range that does not significantly impair the effects of the composition. These may be used alone or in combination of two or more kinds.

[0068] In terms of recyclability, the deep drawing packaging film of the present invention is preferably such that the resin composition forming all the resin layers constituting the deep drawing packaging film except for the adhesive layer contains a polyolefin resin as a main component. Also, the deep drawing packaging film of the present invention is preferably free of a polyamide resin.

[0069] [Method for producing deep drawing packaging film] The deep drawing packaging film of the present invention can be produced by using the resin composition by a known method, such as an extrusion lamination method, a coextrusion inflation method, a coextrusion T-die method, etc. In particular, the coextrusion T-die method is preferably used because the film-forming process is the same even when the number of layers of the film is large, and thickness control is relatively easy. That is, the deep drawing packaging film of the present invention is preferably a coextrusion multilayer film. Furthermore, the deep drawing packaging film of the present invention may be either a non-stretched film or a stretched film, but is usually a non-stretched film.

[0070] Examples of the configuration of the deep drawing packaging film of the present invention are shown below, but the present invention is not limited to these. (1) LLDPE (outer layer) / middle layer / inner layer (2) LLDPE (outer layer) / adhesive layer / middle layer / inner layer (3) LLDPE (outer layer) / adhesive layer / middle layer / adhesive layer / inner layer (4) LLDPE (outer layer) / adhesive layer / middle layer / adhesive layer / LLDPE (adjacent layer) / inner layer (5) LLDPE (outer layer) / adjacent layer / adhesive layer / middle layer / adhesive layer / LLDPE (adjacent layer) / inner layer (6) LLDPE (outer layer) / adjacent layer / adhesive layer / middle layer / adhesive layer / adjacent layer / inner layer (7) rPP (outer layer) / middle layer / inner layer (8) rPP (outer layer) / adhesive layer / middle 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) / middle layer / inner layer (14) LLDPE (outer layer) / middle layer / adhesive layer / gas barrier layer / adhesive layer / inner layer (15) LLDPE (outer layer) / adjacent layer / middle layer / adhesive layer / gas barrier layer / adhesive layer / inner layer (16) LLDPE (outer layer) / middle layer / adhesive layer / gas barrier layer / adhesive layer / adjacent layer / inner layer (17) rPP (outer layer) / middle layer / adhesive layer / gas barrier layer / adhesive layer / inner layer (18) rPP (outer layer) / adjacent layer / middle layer / adhesive layer / gas barrier layer / adhesive layer / inner layer (19) rPP (outer layer) / middle layer / adhesive layer / gas barrier layer / adhesive layer / adjacent layer / inner layer

[0071] In addition, when the deep-drawn packaging film of the present invention has a resin layer formed from a resin composition containing recycled raw materials using the deep-drawn packaging film as a starting material, the deep-drawn packaging film can be obtained by a manufacturing method including a step of preparing a recycled raw material using the deep-drawn packaging film as a starting material, and a step of co-extruding the resin composition containing the recycled raw materials to obtain a deep-drawn packaging film consisting of at least three resin layers: an outer layer, an intermediate layer, and an inner layer.

[0072] Examples of the recycled raw material in the process of producing the recycled raw material using the deep drawing packaging film as a starting raw material include fluff and repellets obtained from the deep drawing packaging film.

[0073] In addition, fluff or repellet can be obtained from the deep drawing packaging film by a known method, for example, by subjecting the deep drawing packaging film to cutting, crushing, drying, melt-kneading, etc. These treatments may be performed alone or in combination of two or more.

[0074] In the process of obtaining a deep drawing packaging film consisting of at least three resin layers, an outer layer, an intermediate layer, and an inner layer, by co-extruding the resin composition containing the recycled raw material, the deep drawing packaging film may be produced by co-extruding a resin composition containing fluff or repellets obtained from the deep drawing packaging film as the recycled raw material with another resin composition. As described above, the resin composition containing the recycled raw material may form any of the resin layers of the deep drawing packaging film, but it is preferable to form the adjacent layer or adhesive layer, and it is particularly preferable to form the adjacent layer.

[0075] <Deep drawing packaging film> The deep drawing packaging film of the present invention thus obtained comprises at least three resin layers, that is, an outer layer, an intermediate layer, and an inner layer.

[0076] The thickness of the deep drawing 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, and even more preferably 70 μm or more and less than 200 μm. By making the thickness 50 μm or more, the film has deep drawing formability and a thickness that is practically problem-free after deep drawing, and can impart mechanical strength and heat resistance. By making the thickness less than 300 μm, deep drawing formability can be imparted and costs can be reduced.

[0077] The internal haze value of the deep drawing packaging film of the present invention, calculated from the total light transmittance and diffuse transmittance measured based on JIS K7136 (2000), is preferably 30% or less from the viewpoint of visibility of the contents, more preferably 25% or less, and even more preferably 20% or less.

[0078] The deep drawing packaging film of the present invention has a puncture energy measured at 23°C according to JIS K7124-2 (1999) using a hydroshot high-speed tester of preferably 0.50 J or more, more preferably 0.60 J or more. The puncture displacement is preferably 10 mm or more, more preferably 15 mm or more. By keeping the puncture energy and puncture displacement at 23°C within the above ranges, the film tends to be less prone to breakage or pinholes even when subjected to impacts that occur during packaging of contents, for example, during transportation.

[0079] The deep drawing packaging film of the present invention has a puncture energy measured at 5°C according to JIS K7124-2 (1999) using a hydroshot high-speed tester of preferably 0.50 J or more, more preferably 0.60 J or more. The puncture displacement is preferably 10 mm or more, more preferably 12 mm or more. By keeping the puncture energy and puncture displacement at 5°C within the above ranges, pinholes tend not to occur even when the contents are packaged and stored at low temperatures, such as refrigerated storage.

[0080] The deep drawing packaging film of the present invention preferably has a puncture energy of 0.35 J or more, more preferably 0.4 J or more, measured at -20°C according to JIS K7124-2 (1999) using a hydroshot high-speed tester. The puncture displacement is preferably 5 mm or more, more preferably 7 mm or more. By setting the puncture energy and puncture displacement at -20°C within the above ranges, pinholes tend not to occur even when the contents are packaged and stored at low temperatures, such as frozen storage.

[0081] In addition, when the deep drawing packaging film of the present invention has a gas barrier layer, the gas permeability of the deep drawing packaging film when made to a thickness of 100 μm is 10.0 cc / m 2 ·24hr·atm or less is preferable, and 8.5cc / m 2 ·24hr·atm or less, and more preferably 7.0cc / m 2 Gas permeability is 10.0cc / m 2 By keeping the humidity at or below 24hr·atm, it tends to be possible to impart the gas barrier properties required for use as packaging.

[0082] The deep drawing packaging film of the present invention can be used not only as a recycled raw material for the deep drawing packaging film, but also as a starting raw material for producing other resin films, to produce resin films (resin layers) using the recycled raw material made from the deep drawing packaging film. The other resin film is not particularly limited, but is preferably a resin film containing a polyolefin resin as a main component, since it has high compatibility and can increase the recycling rate.

[0083] <Package> The deep drawing packaging film of the present invention is suitable for deep drawing packages, but can be used to make various packages depending on the contents. Examples of packages are shown below. (1) Deep-drawn packaging (2) Pouch packaging (3) Pillow packaging (4) Vacuum packaging Among these, deep-draw packaging products are preferred, and particularly preferred are deep-draw packaging products using the above-mentioned deep-draw packaging film as a base material.

[0084] When the deep drawing packaging film of the present invention is used to produce a deep drawing package, it is preferable to produce it without stretching in order to improve formability during drawing. For pouch packaging, pillow packaging and vacuum packaging, it is preferable to produce it without stretching, and then laminate it with a stretched film such as a biaxially stretched polypropylene film by a dry lamination method or the like from the viewpoint of imparting strength and gas barrier properties. EXAMPLES

[0085] The present invention will be described in more detail below based on examples carried out to clarify the effects of the present invention. Note that the present invention is not limited to the following examples and comparative examples.

[0086] The materials used in the outer layer, middle layer, inner layer, and other layers (adhesive layer, gas barrier layer, etc.) are shown below. PE1: Ultzekkus 3520L (Prime Polymer, LLDPE) PE2: Admer NF567 (manufactured by Mitsui Chemicals, PE-based adhesive resin) PE3: UltZex 2021L (Prime Polymer, LLDPE) PE4: Yumerit 2040FC (Ube Maruzen Polyethylene Co., Ltd., LLDPE) rPP: Prime Polypro F-724NPC (Prime Polymer, rPP) PP1: Tafmer PN3560 (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 (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 ethylene content of 32 mol%, MFR 3.8 g / 10 min (210°C), melting point 183°C) PA: UBE Nylon 1030B (Ube Industries, PA6)

[0087] 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 to PE4 and rPP are shown in Table 1 below. The MFR, glass transition temperature, melting point and storage 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.

[0088] (MFR) The MFR of each raw material was measured at a temperature of 230°C and a load of 2.16 kg in accordance with JIS K7210-1 Method A (2014).

[0089] (Melting point and glass transition temperature) In accordance with JIS K7121 (2012), the melting point (Tm) and glass transition temperature (Tg) of each raw material were measured by heating the material at a rate of 10°C / min using a differential scanning calorimeter (PerkinElmer, "DSC8000").

[0090] (Storage modulus E') In accordance with JIS K7244-10 (2005), the storage modulus E' was measured at 90°C and -20°C in tension mode with a vibration frequency of 10 Hz using a rheometer ("DiscoveryHR2" manufactured by TA Instruments).

[0091] [Table 1]

[0092] [Table 2]

[0093] <Examples 1 to 6 and Comparative Example 1> The raw materials were melt-kneaded at 220°C with the composition and layer structure shown in Table 3 below, and extruded from a lamination die at 230°C to produce a deep-draw packaging film with a thickness of 100 µm.

[0094] <Reference example> Each raw material was melt-kneaded at 250°C with the composition and layer structure shown in Table 3 below, and extruded from a lamination die at 250°C to produce a deep-draw packaging film with a thickness of 100 µm.

[0095] 〔evaluation〕 The deep drawing packaging films of Examples 1 to 6 and Comparative Example 1 were evaluated for impact resistance, transparency, deep drawing formability, recyclability, and gas barrier properties. The results are shown in Table 3 below.

[0096] (shock resistance) The deep drawing packaging film was measured for puncture energy and puncture displacement using a method in accordance with JIS K7124-2 (1999) at a speed of 3 m / sec, height of 200 mm, striker φ12.7 mm, and test atmosphere temperatures of 23°C, 5°C, and -20°C. The results were evaluated according to the following criteria. [Evaluation criteria for test ambient temperature 23℃] ○: Puncture energy is 0.5 J or more and puncture displacement is 10 mm or more △: Puncture energy is 0.2 J or more and less than 0.5 J, and the puncture displacement is 10 mm or more ×: Puncture energy is less than 0.2 J or puncture displacement is less than 10 mm [Evaluation criteria for test atmosphere temperature 5℃] ○: Puncture energy is 0.5 J or more and puncture displacement is 10 mm or more △: Puncture energy is 0.2 J or more and less than 0.5 J, and the puncture displacement is 10 mm or more ×: Puncture energy is less than 0.2 J or puncture displacement is less than 10 mm [Evaluation criteria for test ambient temperature -20℃] ○: Puncture energy is 0.5 J or more and puncture displacement is 5 mm or more △: Puncture energy is 0.2 J or more and less than 0.5 J, and the puncture displacement is 5 mm or more ×: Puncture energy is less than 0.2 J or puncture displacement is less than 5 mm

[0097] (transparency) Using a turbidity meter (manufactured by Nippon Denshoku Industries Co., Ltd., "NDH 5000"), the surface of the deep drawing packaging film was irradiated with light, and the haze was measured in accordance with JIS K7136 (2000) and evaluated according to the following criteria. [Evaluation Criteria] ○: Internal haze is 30% or less ×: Internal haze exceeds 30%

[0098] (Deep draw formability) Using a deep-draw packaging machine (Omori Machinery Industry FV6300), the product was deep-drawn into a cylindrical shape with a diameter of 98 mm and a drawing depth of 30 mm under conditions of a molding heating temperature of 95°C, a molding heating time of 2 seconds, and a molding time of 2 seconds.The corner thicknesses of the positions where the circumference of the bottom surface was divided into four equal parts (any point on the circumference was used as the base point and the circumference was divided into four equal parts) were measured in μm units, and the minimum corner thickness was evaluated according to the following criteria. [Evaluation criteria (thickness)] ○: Corner thickness is 10μm or more ×: Corner thickness is less than 10 μm

[0099] (Recyclability) 60% by mass of the PE2 and 40% by mass of each of the deep drawing 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 for the deep drawing packaging film, and was evaluated according to the following criteria. [Evaluation Criteria] ○: Internal haze is less than 40% ×: Internal haze is 40% or more

[0100] (Gas barrier properties) The oxygen permeability (cc / m) of the multilayer film thus produced was measured at 23°C and 0% RH using an oxygen permeability measuring device (OX-Tran2 / 21: manufactured by MOCON) in accordance with JIS K7126-2 (2006). 2 ·24hr·atm) and evaluated according to the following criteria. ○: 10.0cc / m 2 ·24hr・atm or less ×:10.0cc / m 2 ·24hr·Exceeds ATM

[0101] [Table 3]

[0102] The deep drawing packaging films of Examples 1 to 6 not only had excellent impact resistance, but also had good transparency when recycled and added to polyolefin resins. Furthermore, compared to the deep drawing packaging film of Comparative Example 1, they were able to suppress thinning of the corners during deep drawing molding. [Industrial Applicability]

[0103] According to the deep drawing packaging film of the present invention, it is possible to provide a deep drawing packaging film that is excellent in impact resistance, deep drawing formability, and further in recyclability, and a package using the same.

Claims

1. The deep drawing packaging film comprises at least four resin layers, namely, an outer layer, an intermediate layer, an inner layer, and a gas barrier layer, wherein the resin composition forming the gas barrier layer contains an ethylene-vinyl alcohol-based resin as a main component, 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 contains, as a main component, a copolymer of propylene and ethylene or a mixture of a polypropylene-based resin and a polyethylene-based resin. (3) When the resin composition forming the intermediate layer is taken as 100% by mass, the ethylene content is 4% by mass or more and 50% by mass or less.

2. 2. The deep drawing packaging film according to claim 1, wherein the resin composition forming all of the resin layers constituting the deep drawing packaging film contains a polyolefin resin as a main component.

3. The deep drawing packaging film according to claim 1 or 2, wherein any of the resin layers contains recycled material made from the deep drawing packaging film as a starting material.

4. The deep drawing packaging film according to any one of claims 1 to 3, wherein the internal haze of the deep drawing packaging film is 30% or less.

5. A deep drawing packaging body using the deep drawing packaging film according to any one of claims 1 to 4 as a base material.

6. A polyolefin resin film containing recycled raw materials made from the deep drawing packaging film according to any one of claims 1 to 4.

7. A method for producing a deep-drawn packaging film consisting of at least three resin layers, an outer layer, an intermediate layer and an inner layer, using a recycled raw material starting from the deep-drawn packaging film described in any one of claims 1 to 4, comprising the steps of: preparing a recycled raw material starting from the deep-drawn packaging film; and co-extruding a resin composition containing the recycled raw material to obtain a deep-drawn packaging film consisting of at least three resin layers, an outer layer, an intermediate layer and an inner layer.

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