Film, film for deep drawing packaging, and recycled film

Abstract

To provide a film which is excellent in mechanical physical properties such as piercing strength and impact resistance, transparency and recyclability.SOLUTION: A film has at least a layer (A) formed of a resin composition containing a polypropylene-based resin and an ethylene-octene copolymer, wherein, when the total of the polypropylene-based resin and the ethylene-octene copolymer contained in the resin composition is 100 mass%, more than 20 mass% and 60 mass% or less of the ethylene-octene copolymer is contained.SELECTED DRAWING: None

Description

[Technical Field]

[0001] The present invention relates to a film, a deep-draw packaging film, and a recycled film, and more particularly to a film, a deep-draw packaging film, and a recycled film that are excellent in mechanical properties such as puncture strength and impact resistance, transparency, and recyclability. [Background technology]

[0002] In the fields of food packaging and medical packaging, packages (deep-draw packages) are used in which the contents are placed in a base material, which is made by heat-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 of the lid material is adhered or welded to the container. Films used as the base material for deep-draw packages have traditionally been laminated films of various resins, such as a seal layer that provides heat sealing to the lid material, an ethylene-vinyl alcohol copolymer layer that provides gas barrier properties, and a polyamide layer that provides impact resistance and deep-draw 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. For example, Patent Document 2 discloses a technology for recycling laminated films, in which film pieces discarded during production are returned to a portion of the polyolefin layer (recycled layer) and reused. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Application Laid-Open No. 2006-224470 [Patent Document 2] Japanese Patent Application Laid-Open No. 2016-087892 Summary of the Invention [Problem to be solved by the invention]

[0005] Generally, polyamide resins are used to impart mechanical properties such as puncture strength and impact resistance to films. However, polyamide resins are poorly compatible with polyolefin resins, so when a film containing a polyamide resin is blended with a polyolefin layer for recycling, the transparency is significantly reduced. Therefore, films containing polyamide resins have the problem that the amount of recycled raw material added cannot be increased and the recycled raw material-containing layer must be made thinner, which makes it difficult to increase the recycling rate.

[0006] Therefore, an object of the present invention is to provide a film, a deep-draw packaging film, and a recycled film that are excellent in mechanical properties such as puncture strength and impact resistance, transparency, and recyclability. [Means for solving the problem]

[0007] In view of the above circumstances, the present inventors conducted extensive research and found that a film having a layer containing a polypropylene-based resin and a specific amount of ethylene-octene copolymer has mechanical properties such as puncture strength and impact resistance equivalent to those of a film not using a polyamide-based resin, as well as transparency and excellent recyclability, and thus completed the present invention.

[0008] That is, the gist of the present invention is the following [1] to [9]. [1] A film having at least a layer (A) formed from a resin composition containing a polypropylene-based resin and an ethylene-octene copolymer, wherein the ethylene-octene copolymer is contained in an amount of more than 20% by mass and not more than 60% by mass, where the total amount of the polypropylene-based resin and the ethylene-octene copolymer contained in the resin composition is 100% by mass. [2] The film according to [1], wherein the peak temperature of the loss tangent (tanδ) of the layer (A) measured in accordance with JIS K7244-10 (2005) at a vibration frequency of 10 Hz is −40° C. or lower and the peak value is 0.045 or higher. [3] The film according to [1] or [2], which comprises at least two layers and has a layer (B) formed from a resin composition containing a polyethylene resin as a main component. [4] The film according to any one of [1] to [3], which comprises at least three layers and has a layer (C) formed from a resin composition containing a gas barrier resin as a main component. Laminated film. [5] The film according to [4], wherein the gas barrier resin is an ethylene vinyl alcohol resin. [6] A deep drawing packaging film using the film according to any one of [1] to [5]. [7] A recycled film having at least a layer (A) formed from a resin composition containing a polypropylene resin and an ethylene-octene copolymer, wherein the resin composition contains recycled raw materials obtained by using the film according to any one of [1] to [5] as a starting material. [8] A recycled film having at least three layers: a layer (A) formed from a resin composition containing a polypropylene-based resin and an ethylene-octene copolymer; a layer (B) formed from a resin composition containing a polyethylene-based resin as a main component; and a layer (C) formed from a resin composition containing a gas barrier resin as a main component, wherein at least one of the resin compositions forming layers (A) to (C) contains a recycled material obtained by using the film according to any one of [1] to [5] as a starting material. [9] A deep drawing packaging film made from recycled film according to [7] or [8]. [Effects of the Invention]

[0009] The film and laminated film of the present invention have mechanical properties and transparency equivalent to those of conventional films containing polyamide resins, and are excellent in recyclability. DETAILED DESCRIPTION OF THE INVENTION

[0010] Hereinafter, embodiments of the present invention will be described in detail, but the present invention is not limited to the embodiments described below.

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

[0012] Furthermore, when it is written as "X to Y" (X and Y are any numbers), unless otherwise specified, it means "X or more and Y or less," as well as "preferably greater than X" and "preferably smaller than Y." In this specification, "x and / or y (x and y are optional configurations)" means at least one of x and y, and can mean three possibilities: x only, y only, or x and y. In addition, even if the upper and lower limit values ​​of the numerical ranges in this specification are slightly outside the numerical range specified by the present invention, they are considered to be included in the equivalent range of the present invention as long as they have the same functional effects as those within the numerical range. In the present specification, when numerical ranges are described in stages, the upper or lower limit of a certain numerical range can be arbitrarily combined with the upper or lower limit of another numerical range. In addition, in the numerical ranges described in this specification, the upper or lower limit of the numerical range can also be replaced with the values ​​shown in the examples.

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

[0014] In addition, in this specification, "compatible" refers to a state in which different resins are dissolved and mixed at the molecular order, and "compatible" refers to a state in which different resins that are not compatible are appropriately dispersed.

[0015] A film according to one embodiment of the present invention (hereinafter referred to as "the film") has at least a layer (A) formed from a resin composition containing a polypropylene-based resin and an ethylene-octene copolymer, and contains more than 20% by mass and not more than 60% by mass of the ethylene-octene copolymer, where the total of the polypropylene-based resin and the ethylene-octene copolymer contained in the resin composition is taken as 100% by mass. The film will now be described.

[0016] <Layer(A)> As described above, the layer (A) is formed from a resin composition containing a polypropylene resin and an ethylene-octene copolymer.

[0017] [Polypropylene resin] The polypropylene resin includes a resin mainly composed of a propylene structural unit, such as a propylene homopolymer or a copolymer of propylene with another α-olefin, such as ethylene or butene, and the copolymer may be either a random copolymer or a block copolymer. The stereoregularity may be any of an isotactic structure, a syndiotactic structure, an atactic structure, a stereoblock structure, etc.

[0018] Specific examples include random polypropylene (rPP), block polypropylene (bPP), homopolypropylene (hPP), propylene-α-olefin copolymer, ethylene-propylene-α-olefin copolymer, etc. These can be used alone or in combination of two or more. Among them, random polypropylene (rPP) and homopolypropylene (hPP) are preferred from the viewpoint of heat resistance, and homopolypropylene (hPP) is more preferred.

[0019] Examples of the α-olefin include α-olefins having 2 to 20 carbon atoms. Specific examples include ethylene, 1-butene, 1-pentene, 1-hexene, 1-heptene, 1-octene, 1-nonene, 1-decene, 1-undecene, 1-dodecene, 1-tridecene, 1-tetradecene, 1-pentadecene, 1-hexadecene, 1-heptadecene, 1-octadecene, 1-nonadecene, 1-eicosene, 3-methyl-1-butene, 3-methyl-1-pentene, 4-methyl-1-pentene, 2-ethyl-1-hexene, and 2,2,4-trimethyl-1-pentene. These may be used alone or in combination of two or more.

[0020] The melt flow rate (MFR) of the polypropylene resin (JIS K7210-1 Method A (2014), 230°C, load 2.16 kg) is usually 0.1 to 50 g / 10 min, preferably 0.3 to 20 g / 10 min, from the viewpoint of film formability.

[0021] The melting point of the polypropylene resin is usually 120 to 180°C, preferably 125 to 175°C, and more preferably 128 to 170°C, from the viewpoint of deep drawability.

[0022] The content of the polypropylene resin in the resin composition is usually 40% by mass or more, preferably 45% by mass or more, more preferably 50% by mass or more, from the viewpoint of transparency. There is no particular upper limit, but it is usually 95% by mass or less, preferably 90% by mass or less, more preferably 80% by mass or less, and particularly preferably 75% by mass or less.

[0023] [Ethylene-octene copolymer] The resin composition contains an ethylene-octene copolymer, and preferably contains an ethylene-octene block copolymer. By using the ethylene-octene copolymer, the copolymer is appropriately dispersed in the polypropylene-based resin, resulting in excellent transparency. In addition, craze deformation occurs in a well-balanced manner when an impact is applied, thereby improving mechanical properties such as puncture strength and impact resistance.

[0024] The melt flow rate (MFR) of the ethylene-octene copolymer (JIS K7210-1 A method (2014), 190°C, load 2.16 kg) is usually 0.1 to 50 g / 10 min, preferably 0.3 to 20 g / 10 min, from the viewpoint of film formability.

[0025] The density (JIS K7112) of the ethylene-octene copolymer is usually 0.82 to 0.92 g / cm from the viewpoint of film-forming properties. 3 and preferably 0.84 to 0.90 g / cm 3 is.

[0026] Examples of commercially available ethylene-octene copolymers include "INFUSE9507," "INFUSE9530," and "engage8842" manufactured by DOW.

[0027] The content of the ethylene-octene copolymer in the resin composition is usually 10 to 80% by mass, preferably 15 to 75% by mass, and particularly preferably 25 to 55% by mass, from the viewpoint of mechanical properties.

[0028] In addition, from the viewpoint of mechanical properties, the content of the ethylene-octene copolymer is more than 20% by mass and not more than 60% by mass, preferably not less than 23% by mass and not more than 55% by mass, and more preferably not less than 25% by mass and not more than 45% by mass, when the total of the polypropylene resin and the ethylene copolymer is taken as 100% by mass.

[0029] [Other resins] The resin composition may contain thermoplastic resins such as polyolefin resins other than the polypropylene resins and ethylene-octene copolymers (e.g., polyethylene resins, α-olefin copolymers, cyclic polyolefin resins, modified polyolefin resins, etc.), ethylene-vinyl alcohol copolymers (hereinafter referred to as "EVOH"), polyamide resins, etc., within a range that does not impair the effects of the present invention (e.g., 10 mass % or less of the resin composition, preferably 5 mass % or less).

[0030] [Additives] Furthermore, for the purpose of improving or adjusting various properties such as moldability and productivity, the resin composition may contain 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 modifiers, crosslinking agents, lubricants, nucleating agents, plasticizers, antioxidants, etc., as appropriate, within the range that does not significantly impair the effects of the present invention. These may be used alone or in combination of two or more.

[0031] [Recycled raw materials] The resin composition also preferably contains recycled raw materials derived from the present film, deep-draw packaging, scraps generated during the production process of the present film, other resin films, molded articles, etc. That is, the polypropylene resin and ethylene-octene copolymer contained in the present film may be derived in part or entirely from recycled raw materials. In particular, from the viewpoint of recyclability and transparency, it is preferable that the resin composition contains recycled raw materials made from scraps generated during the manufacturing process of the present film, packaging, the present film, and the laminated film described below, and it is particularly preferable that the resin composition contains recycled raw materials made from the present film. From the viewpoint of recyclability, it is also preferable to include recycled raw materials made from other resin films as starting materials, and it is particularly preferable to include recycled raw materials made from resin films containing polypropylene resins and / or ethylene-octene copolymers as starting materials.

[0032] As the recycled raw material, a film, a packaging material, etc. may be used as it is, or the film, packaging material, etc. may be used after being made into fluff, re-pellets, etc. Among these, from the viewpoint of workability, it is preferable to use the film, packaging material, etc. after being made into fluff or re-pellets.

[0033] The "fluff" is made by crushing film, and the "repellet" is made by melting and kneading film, packaging material, etc. and processing it into pellets.

[0034] When the resin composition 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. In addition, if the recycled raw materials contain polypropylene resins or ethylene-octene copolymers, these will be included in the content of each resin.

[0035] The glass transition temperature of the layer (A) is usually 20°C or lower, preferably 15°C or lower, and more preferably 10°C or lower. By adjusting 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, preferably -70°C. The glass transition temperature can be measured in accordance with JIS K7121 (2012) using a differential scanning calorimeter by increasing the temperature of each raw material at a rate of 10°C / min.

[0036] The peak temperature of the loss tangent (tanδ) of the layer (A) measured at a vibration frequency of 10 Hz in accordance with JIS K7244-10 (2005) is preferably −40° C. or lower, more preferably −42° C. or lower, and particularly preferably −45° C. or lower. The lower limit is usually −80° C. or lower, preferably −70° C. or lower. The peak value of the loss tangent (tan δ) is preferably 0.045 or more, more preferably 0.047 or more, and particularly preferably 0.05 or more. There is no particular upper limit, but it is usually 0.12 or less. By setting the peak temperature of the loss tangent (tan δ) to the above-mentioned value or less and the peak value to the above-mentioned value or more, low-temperature impact resistance tends to be imparted.

[0037] The thickness of the layer (A) is usually 10 to 100 μm, preferably 15 to 80 μm, and more preferably 20 to 60 μm. By setting the thickness of the layer (A) within the above range, it tends to be possible to impart film formation stability, mechanical properties, and deep drawability.

[0038] <Layer (B)> The present film preferably comprises at least two layers, including layer (B) formed from a resin composition containing a polyethylene resin as a main component in addition to layer (A). Alternatively, the present film may comprise two or more layers (B). When the present film has layer (B), layer (B) can be used as an inner layer or an intermediate layer.

[0039] In this specification, the term "inner layer" refers to the layer that comes into contact with the contents when combined with a lid to form a deep-draw package, the term "outer layer" refers to the layer that comes into contact with the outside air when combined with a lid to form a deep-draw package, and the term "intermediate layer" refers to the layer sandwiched between the inner and outer layers.

[0040] [Polyethylene resin] Examples of the polyethylene resin include resins containing ethylene structural units as a main component, such as very low density polyethylene (VLDPE), linear low density polyethylene (LLDPE), low density polyethylene (LDPE), medium density polyethylene (MDPE), high density polyethylene (HDPE), and ethylene-vinyl acetate copolymer (EVA). The polyethylene resin may also contain an α-olefin unit. These may be used alone or in combination of two or more. Among these, linear low density polyethylene is preferred.

[0041] Examples of the α-olefin include α-olefins having 3 to 20 carbon atoms. Specific examples include propylene, 1-butene, 1-pentene, 1-hexene, 1-heptene, 1-octene, 1-nonene, 1-decene, 1-undecene, 1-dodecene, 1-tridecene, 1-tetradecene, 1-pentadecene, 1-hexadecene, 1-heptadecene, 1-octadecene, 1-nonadecene, 1-eicosene, 3-methyl-1-butene, 3-methyl-1-pentene, 4-methyl-1-pentene, 2-ethyl-1-hexene, and 2,2,4-trimethyl-1-pentene. These may be used alone or in combination of two or more. Of these, α-olefins having 4 to 10 carbon atoms are preferred, 1-butene, 1-hexene, 1-octene and 4-methyl-1-pentene are more preferred, and 4-methyl-1-pentene is even more preferred.

[0042] The melt flow rate (MFR) of the polyethylene resin (JIS K7210-1 Method A (2014), 190°C, load 2.16 kg) is usually 0.1 to 50 g / 10 min, preferably 0.3 to 20 g / 10 min, from the viewpoint of film formability.

[0043] The resin composition may contain a polyolefin resin other than the polyethylene resin (e.g., polyethylene resin, polypropylene resin, α-olefin copolymer, cyclic polyolefin resin, modified polyolefin resin, etc.), or a thermoplastic resin such as ethylene-vinyl alcohol or polyamide resin, within a range that does not impair the effects of the present invention (e.g., 10 mass % or less of the resin composition, preferably 5 mass % or less).

[0044] Furthermore, for the purpose of improving or adjusting various properties such as moldability and productivity, the resin composition may contain the additives described in connection with the layer (A) above, within a range that does not significantly impair the effects of the present invention.

[0045] The resin composition preferably has an ethylene content of 50% by mass or more, more preferably 60% by mass or more, and particularly preferably 70% by mass or more, when the resin composition is taken as 100% by mass. By setting the ethylene content of the resin composition within the above range, the heat sealability tends to be good.

[0046] The thickness of the layer (B) (single layer) is usually 10 to 100 μm, preferably 15 to 80 μm, and more preferably 20 to 60 μm. By setting the thickness of the layer (B) within the above range, it tends to be possible to impart film formation stability, impact resistance, and deep drawability.

[0047] <Layer(C)> The present film preferably has a layer (C) formed from a resin composition containing a gas barrier resin as a main component, and is composed of at least three layers, or may have two or more layers (C). When the present film has layer (C), layer (C) can be used as an intermediate layer.

[0048] Examples of the gas barrier resin include EVOH, polyamide resins, etc. These may be used alone or in combination of two or more. In the present film, from the viewpoint of recyclability, it is preferable to use EVOH as the gas barrier resin, and from the viewpoint of recyclability, it is also preferable that the film does not contain a polyamide resin.

[0049] [EVOH] The EVOH is a resin obtained by saponifying a copolymer of ethylene and vinyl acetate with an alkali catalyst or the like.

[0050] The content of ethylene structural units in the EVOH is not particularly limited, but from the viewpoint of film formation stability, it is usually 29 mol% or more, preferably 32 mol% or more, and from the viewpoint of gas barrier properties, it is usually 47 mol% or less, preferably 44 mol% or less. The saponification degree of EVOH is usually 90% or more, preferably 95% or more. By setting the content of ethylene structural units and the degree of saponification of EVOH within the above ranges, it tends to be possible to improve the gas barrier properties, mechanical strength, etc. These may be used alone or in combination of two or more.

[0051] It should be noted that the EVOH is not limited to those produced by saponification, as long as they have a similar chemical structure.

[0052] [Polyamide resin] The polyamide resin is not particularly limited, but examples thereof include aliphatic polyamides such as polyamide 6, polyamide 11, polyamide 12, polyamide 4,10, polyamide 5,10, polyamide 6,10, polyamide 8,10, polyamide 9,10, polyamide 10,10, and polyamide 10,12; semi-aromatic polyamides such as polyamide 10,T and polyamide 11,T; and copolymers of polyamide 10 or polyamide 11 with polyalkylene ether glycol. These may be used alone or in combination of two or more. Among these, aliphatic polyamides are preferred, with polyamide 6, polyamide 6,6, polyamide 11, and polyamide 12 being more preferred. Polyamide 6 is even more preferred because it also has impact resistance.

[0053] The resin composition may contain, for example, a polyolefin resin (e.g., a polyethylene resin, a polypropylene resin, an α-olefin copolymer, a cyclic polyolefin resin, a modified polyolefin resin, etc.) within a range that does not impair the effects of the present invention (e.g., 10% by mass or less of the resin composition, preferably 5% by mass or less).

[0054] Furthermore, for the purpose of improving or adjusting various properties such as moldability and productivity, the resin composition may contain the additives described in connection with the layer (A) above, within a range that does not significantly impair the effects of the present invention.

[0055] When the present film has a gas barrier resin layer, its thickness (single layer) is usually 5 to 50 μm, preferably 7 to 40 μm or more, and more preferably 10 to 35 μm. If the thickness of the barrier resin layer is above this numerical value, good oxygen barrier properties tend to be obtained, and if the thickness is below this numerical value, the deep drawability of the film tends to be good.

[0056] [Other layers] The present film may have other layers in addition to the layers (A) to (C), such as an inner layer, an outer layer, an intermediate layer, an adhesive layer, etc. The present film may also have two or more of the intermediate layers, adhesive layers, etc.

[0057] [Inner layer] The inner layer is the layer other than the layers (A) to (C) and is formed from a resin composition containing a polyolefin resin as a main component. Since the polyolefin resin has heat-sealing properties, the inner layer also functions as a heat-sealing layer.

[0058] Examples of polyolefin resins used in the inner layer include ethylene-α-olefin copolymers, ethylene-acrylic acid copolymers (EAA), ethylene-methyl acrylate copolymers (EMA), ethylene-ethyl acrylate copolymers (EEA), ethylene-methacrylic acid copolymers (EMAA), ethylene-methyl methacrylate copolymers (EMMA), ionomer resins, ethylene-vinyl acetate copolymers (EVA) with a vinyl acetate content of 8 mol% to 40 mol%, hot melt resins (HM), the above-mentioned polypropylene resins and polyethylene resins, and resins obtained by modifying the above-mentioned polyolefin resins with unsaturated carboxylic acids or derivatives thereof. These may be used alone or in combination of two or more.

[0059] Examples of the unsaturated carboxylic acid include acrylic acid, methacrylic acid, fumaric acid, crotonic acid, itaconic acid, citraconic acid, etc., as well as esters and anhydrides thereof, which may be used alone or in combination of two or more.

[0060] Examples of the derivatives of the unsaturated carboxylic acid include methyl acrylate, methyl methacrylate, ethyl acrylate, propyl acrylate, butyl acrylate, butyl methacrylate, glycidyl acrylate, glycidyl methacrylate, acrylamide, methacrylamide, sodium acrylate, and derivatives to which vinyl acetate, etc. are added. These may be used alone or in combination of two or more.

[0061] The polyolefin resin is appropriately selected depending on the shape of the deep-drawn package and the shape and type of the contents.

[0062] The resin composition may contain a thermoplastic resin such as EVOH or a polyamide resin, within a range that does not impair the effects of the present invention (for example, 10% by mass or less of the resin composition, preferably 5% by mass or less).

[0063] Furthermore, for the purpose of improving or adjusting various properties such as moldability and productivity, the resin composition may contain the additives described in connection with the layer (A) above, within a range that does not significantly impair the effects of the present invention.

[0064] The melting point of the resin composition forming the inner layer is usually 100 to 175° C., preferably 110 to 170° C., and more preferably 115 to 168° C. By adjusting the melting point within the above range, excellent heat sealability can be imparted.

[0065] The thickness of the inner layer is usually 5 to 100 μm, preferably 7 to 80 μm, and more preferably 10 to 60 μm. By setting the thickness of the inner layer within the above range, film formation stability and sufficient sealing properties can be imparted.

[0066] [Outer layer] The outer layer is other than the layers (A) to (C) and is provided for the purpose of improving the formability of the film. The outer layer is preferably formed from a resin composition containing a polyolefin resin as a main component.

[0067] Examples of polyolefin resins used in the resin composition forming the outer layer include the polyethylene resins, polypropylene resins, ethylene-α-olefin copolymers, ethylene-acrylic acid copolymers (EAA), ethylene-methyl acrylate copolymers (EMA), ethylene-ethyl acrylate copolymers (EEA), ethylene-methacrylic acid copolymers (EMAA), ethylene-methyl methacrylate copolymers (EMMA), ionomer resins, ethylene-vinyl acetate copolymers (EVA) having a vinyl acetate content of 8 mol% to 40 mol%, hot melt resins (HM), the polypropylene resins, polyethylene resins, and polyolefin resins modified with unsaturated carboxylic acids or derivatives thereof. These may be used alone or in combination of two or more.

[0068] The resin composition may contain a thermoplastic resin such as EVOH or a polyamide resin, within a range that does not impair the effects of the present invention (for example, 10% by mass or less of the resin composition, preferably 5% by mass or less).

[0069] Furthermore, for the purpose of improving or adjusting various properties such as moldability and productivity, the resin composition may contain the additives described in connection with the layer (A) above, within a range that does not significantly impair the effects of the present invention.

[0070] The thickness of the outer layer is usually 5 to 100 μm, preferably 7 to 80 μm, and more preferably 10 to 60 μm. By setting the thickness of the outer layer within the above range, film formation stability and deep drawability can be imparted.

[0071] [Middle class] The intermediate layer is other than the layers (A) to (C), and is disposed to improve film strength and heat resistance and adjust thickness, and is formed from a resin composition containing a polyolefin resin as a main component.

[0072] The polyolefin resin may be the same as that described for the outer layer. The polyolefin resin may be used alone or in combination of two or more. The polyolefin resin used in the intermediate layer may be the same as or different from the polyolefin resin used in the outer layer.

[0073] The resin composition may contain a thermoplastic resin such as EVOH or a polyamide resin, within a range that does not impair the effects of the present invention (for example, 10% by mass or less of the resin composition, preferably 5% by mass or less).

[0074] Furthermore, for the purpose of improving or adjusting various properties such as moldability and productivity, the resin composition may contain the additives described in connection with the layer (A) above, within a range that does not significantly impair the effects of the present invention.

[0075] The thickness of the intermediate layer is usually 3 to 30 μm, preferably 4 to 25 μm, and more preferably 5 to 20 μm. By setting the thickness of the adjacent layer within the above range, film formation stability tends to be imparted. The thickness of the adjacent layer is the total thickness of all intermediate layers in the present laminate film.

[0076] [Adhesive layer] The adhesive layer is provided 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 film may have two or more adhesive layers.

[0077] The adhesive resin may be a resin obtained by modifying the polyolefin resin described in the present film with the unsaturated carboxylic acid or a derivative thereof. The adhesive resin may be used alone or in combination of two or more kinds.

[0078] The resin composition forming the adhesive layer may contain the additives described above for layer (A) for the purpose of improving or adjusting various properties such as moldability and productivity.

[0079] The thickness of the adhesive layer is usually 3 to 30 μm, preferably 4 to 25 μm, and more preferably 5 to 20 μm. By setting the thickness of the adhesive layer within this range, film formation stability and sufficient adhesiveness can be imparted. The thickness of the adhesive layer is the total thickness of all adhesive layers present in the present film.

[0080] [Recycled raw materials] From the viewpoint of recyclability, the present film may contain the above-mentioned recycled raw materials in at least one of the resin compositions forming each layer, in addition to the resin composition forming layer (A).

[0081] When the present film contains the recycled raw materials in the resin compositions forming each of the layers, the recycled raw materials may be contained in any of the resin compositions, but are preferably contained in the resin compositions forming Layer (B), Layer (C), outer layer, intermediate layer, and adhesive layer in order to maintain the film's impact resistance, deep drawability, sealability, transparency, gas barrier properties, etc. In particular, the recycled raw materials are preferably contained in a resin composition containing a polyolefin resin as a main component, more preferably a resin composition containing a polyethylene resin as a main component (e.g., the resin composition forming Layer (B)).

[0082] When the resin composition forming each layer contains the recycled raw material, the content thereof is usually 40% by mass or less, preferably 30% by mass or less, of the resin composition.

[0083] [Method for manufacturing the present film] The present film can be produced using the resin composition by a known method, such as extrusion lamination, extrusion inflation, or extrusion T-die method. The film may be either a non-stretched film or a stretched film, but is usually a non-stretched film.

[0084] [Layer structure of this film] The layer structure of the present film is exemplified below, but the present film is not limited to this layer structure. (1) Layer (A) / Adhesive layer / Layer (C) / Adhesive layer / Layer (B) (2) Outer layer / adhesive layer / layer (A) / adhesive layer / layer (C) / adhesive layer / layer (B) (3) Outer layer / middle layer / layer (C) / adhesive layer / layer (A) / adhesive layer / layer (B) (4) Outer layer / Adhesive layer / Layer (A) / Adhesive layer / Layer (C) / Adhesive layer / Intermediate layer / Layer (B) (5) Outer layer / adhesive layer / layer (C) / adhesive layer / layer (A) / adhesive layer / intermediate layer / layer (B) (6) Outer layer / layer (A) / adhesive layer / layer (C) / adhesive layer / layer (B) (7) Outer layer / layer (C) / adhesive layer / layer (A) / adhesive layer / layer (B)

[0085] Furthermore, when the present film has a layer formed from a resin composition containing recycled materials using the present film as a starting material, it can be obtained by a manufacturing method comprising a step of producing recycled materials such as fluff and pellets using the present film as a starting material, and a step of co-extruding the resin composition containing the recycled materials to obtain the present film.

[0086] <This film> The film obtained in this manner has mechanical properties and transparency equivalent to those of conventional films containing polyamide-based resins, and because it is a mono-material film made of polyolefin-based resins, it is also highly recyclable.

[0087] The thickness of the present film is usually 50 to 300 μm, preferably 60 to 250 μm, and more preferably 70 to 200 μm. By making the thickness 50 μm or more, deep drawability and a thickness that does not cause practical problems after deep drawing tend to be achieved, and mechanical strength and heat resistance tend to be imparted. By making the thickness less than 300 μm, deep drawability tend to be imparted and costs tend to be reduced.

[0088] The internal haze value of the present film, measured according to JIS K7136 (2000), is preferably 25% or less, more preferably 20% or less, and even more preferably 15% or less, from the viewpoint of visibility of contents.

[0089] (puncture impact strength) The puncture energy of this film measured at -20°C using a Hydroshot high-speed testing machine according to JIS K7124-2 (1999) is preferably 0.2 J or more, more preferably 0.25 J or more, and even more preferably 0.3 J or more. The puncture displacement is preferably 4 mm or more, more preferably 5 mm or more, and even more preferably 6 mm or more. By keeping the puncture energy and 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 low temperatures, for example, frozen.

[0090] (Piercing strength) The film has a puncture strength of preferably 85 N / mm or more, more preferably 90 N / mm, and even more preferably 95 N / mm or more, measured in accordance with JIS Z1707 (2019) at a temperature of -20°C. By keeping the puncture strength at -20°C within the above range, pinholes tend to be less likely to occur even when the contents are packaged and stored at low temperatures, for example, by freezing.

[0091] <Package> The present film can be suitably used as a film for forming various packages such as deep-draw packages, pouch packages, pillow packages, and vacuum packages. In particular, the present film is preferably used for deep-draw packaging. In addition, the deep-draw packaging preferably uses the present film as a deep-draw base material.

[0092] When the present film is used for deep drawing packaging, particularly as a base material for deep drawing, it is preferably produced without stretching in order to improve formability during drawing. Furthermore, when the film is to be pouch-packaged, pillow-packaged, or vacuum-packaged, it is preferable to produce the film without stretching it, and then further laminate it with a stretched film such as a biaxially oriented polypropylene film by dry lamination or the like, from the viewpoint of imparting strength and gas barrier properties.

[0093] <Recycled film> As mentioned above, this film is a mono-material film made of polyolefin resin, so it can be suitably used as a recycled raw material. Therefore, recycled films (resin layers) may be produced using recycled raw materials starting from this film.

[0094] The recycled film is not particularly limited, but is preferably a recycled film having at least the layer (A) in which the resin composition forming layer (A) contains recycled materials made from the present film as a starting material, or a recycled film having at least three layers (A) to (C) in which at least one of the resin compositions forming layers (A) to (C) contains recycled materials made from the present film as a starting material.

[0095] The recycled film can be suitably used as a film for forming various packages such as deep-draw packages, pouch packages, pillow packages, and vacuum packages. In particular, the recycled film is preferably for deep-draw packaging. In addition, the deep drawing package preferably uses a recycled film as a deep drawing base material. [Example]

[0096] The present invention will be described in more detail below based on examples carried out to clarify the effects of the present invention. However, the present invention is not limited to the following examples and comparative examples.

[0097] The following raw materials were prepared:

[0098] [Polypropylene resin] hPP: Homopolypropylene, MFR (230°C, 2.16 kg load) 7.5 g / 10 min rPP: Random polypropylene, MFR (190°C, load 2.16 kg) 7.0 g / 10 min

[0099] [Ethylene-octene copolymer] EO1: Ethylene-octene copolymer, MFR (190°C, load 2.16 kg) 5.0 g / 10 min, density 0.866 g / cm 3 EO2: Ethylene-octene copolymer, MFR (190°C, load 2.16 kg) 5.0 g / 10 min, density 0.887 g / cm 3 EO3: Ethylene-octene copolymer, MFR (190°C, load 2.16 kg) 1.0 g / 10 min, density 0.857 g / cm 3

[0100] [Polyolefin resin] PO1: Ethylene-1-butene copolymer, MFR (190°C, load 2.16 kg) 3.6 g / 10 min PO2: Ethylene-propylene-1-butene copolymer, MFR (230°C, load 2.16 kg) 6.0 g / 10 min PO3: Ethylene-propylene-1-butene copolymer, MFR (230°C, load 2.16 kg) 7.0 g / 10 min

[0101] [EVOH] EVOH: Ethylene-vinyl alcohol copolymer, ethylene content 32 mol%, MFR (210°C, load 2.16 kg) 3.0 g / 10 min

[0102] [Polyamide resin] PA: Polyamide 6, 98% sulfuric acid relative viscosity 4.08

[0103] The raw materials were mixed in a plastic bag so as to obtain the composition shown in Table 1 below, and the mixture was melt-kneaded at 230°C in a φ40 mm single-screw extruder and extruded from a die set at 230°C to produce a film with a thickness of 100 μm.

[0104] The following evaluations were carried out on the films of Examples 1 to 5, Comparative Examples 1 to 7, and Reference Example 1. The results are shown in Tables 1 and 2 below.

[0105] [Puncture impact strength] The puncture energy and displacement of this laminated film were measured at -20°C using a Hydroshot high-speed testing machine in accordance with JIS K7124-2 (1999), and evaluated according to the following criteria. [Evaluation criteria] ○: Puncture energy is 0.3 J or more and displacement is 6 mm or more △: Puncture energy is 0.2J or more but less than 0.3J and displacement is 6mm or more ×: Puncture energy is 0.2 J or less or displacement is less than 6 mm

[0106] [Piercing strength] The puncture strength of this film was measured at a temperature of -20°C in accordance with JIS Z1707 (2019), and evaluated according to the following criteria. [Evaluation criteria] ○:Piercing strength is 95N / mm or more △: Puncture strength is 90N / mm or more and less than 95N / mm ×: Puncture strength less than 90N / mm

[0107] [Peak temperature and peak value of loss tangent (tanδ)] In accordance with JIS K7244-10 (2005), the loss tangent (tan δ) of the film was measured at a vibration frequency of 10 Hz, and the peak temperature and peak value were determined.

[0108] [Transparency] Using a turbidity meter (manufactured by Nippon Denshoku Industries Co., Ltd., "NDH 5000"), the film surface was irradiated with light, and the total haze and internal haze were measured in accordance with JIS K7136 (2000), and evaluated according to the following criteria. [Evaluation criteria] ○: Internal haze is less than 15% △: Internal haze is 15% or more and less than 20% ×: Internal haze is 20% or more

[0109] [Recyclability] Assuming that the films of Examples 1 to 5, Comparative Examples 1 to 7, and Reference Example 1 were recycled into an LLDPE layer, the transparency after recycling was evaluated. Specifically, the films of Examples 1 to 5, Comparative Examples 1 to 7, and Reference Example 1 were laminated together with an LLDPE layer as layer (B) and an EVOH layer as layer (C) to form three layers [film / EVOH / LLDPE = 3 / 1 / 2 mass ratio] to produce laminated films. Assuming that this laminated film would be recycled into a film having an LLDPE layer (24% by mass recycled), the resin compositions for forming the films of Examples 1 to 5, Comparative Examples 1 to 7, and Reference Example 1 were mixed in a mass ratio of 12 / 84 / 4 LLDPE / EVOH, melt-kneaded at 230°C in a φ25 mm twin-screw extruder, and extruded from a die set at 230°C to produce a recycled film with a thickness of 100 μm. The surface of this recycled film was irradiated with light using a turbidity meter (manufactured by Nippon Denshoku Industries Co., Ltd., "NDH 5000"), and the internal haze was measured in accordance with JIS K7136 (2000) and evaluated according to the following criteria. The appearance of the recycled film was also visually inspected and evaluated according to the following criteria. [Transparency Evaluation Criteria] ○: Internal haze is less than 15% △: Internal haze is 15% or more and less than 20% ×: Internal haze is 20% or more Furthermore, the film was evaluated for particles during recycling according to the following criteria. [Appearance evaluation criteria] ○: No visible substance ×: Items can be seen

[0110] [Table 1]

[0111] Although the films of Examples 1 to 5 were made of polyolefin resin, they had mechanical properties such as puncture strength and impact resistance comparable to those of polyamide resin, and were excellent in transparency and recyclability. On the other hand, the films of Comparative Examples 1 and 2, which did not contain a specific amount of ethylene-octene copolymer, and the films of Comparative Examples 3 to 7, which did not contain ethylene-octene copolymer, had low puncture impact strength and pin puncture strength, and were poor in mechanical properties. [Industrial Applicability]

[0112] The present film has excellent mechanical properties, transparency, and recyclability, and can therefore be suitably used as a deep-draw packaging film.

Claims

1. A film having at least a layer (A) formed from a resin composition containing a polypropylene-based resin and an ethylene-octene copolymer, wherein the film contains more than 20% by mass and not more than 60% by mass of the ethylene-octene copolymer when the total amount of the polypropylene-based resin and the ethylene-octene copolymer contained in the resin composition is taken as 100% by mass.

2. 2. The film according to claim 1, wherein the layer (A) has a loss tangent (tanδ) peak temperature of −40° C. or lower and a peak value of 0.045 or higher, measured in accordance with JIS K7244-10 (2005) at a vibration frequency of 10 Hz.

3. The film according to claim 1, which comprises at least two layers and has a layer (B) formed from a resin composition containing a polyethylene resin as a main component.

4. The film according to claim 3, which comprises at least three layers and has a layer (C) formed from a resin composition containing a gas barrier resin as a main component. Laminated film.

5. The film according to claim 4, wherein the gas barrier resin is an ethylene vinyl alcohol resin.

6. A deep drawing packaging film using the film according to any one of claims 1 to 5.

7. A recycled film having at least a layer (A) formed from a resin composition containing a polypropylene resin and an ethylene-octene copolymer, wherein the resin composition contains a recycled material obtained by using the film according to any one of claims 1 to 5 as a starting material.

8. A recycled film having at least three layers: a layer (A) formed from a resin composition containing a polypropylene-based resin and an ethylene-octene copolymer; a layer (B) formed from a resin composition containing a polyethylene-based resin as a main component; and a layer (C) formed from a resin composition containing a gas barrier resin as a main component, wherein at least one of the resin compositions forming layers (A) to (C) contains a recycled material obtained by using the film according to any one of claims 1 to 5 as a starting material.

9. A deep-draw packaging film using the recycled film according to claim 7.

Images