Film, laminated film, package, recycled film, and method for producing laminated film

Abstract

To provide a film that exhibits high transparency, superior recyclability, and superior heat stability, even when containing a polyolefin resin, and a polyamide resin and / or EVOH, which are resins incompatible therewith.SOLUTION: A film has a layer formed from a resin composition containing: 40 mass% or more of a polyolefin resin excluding maleic anhydride-modified polyolefin resins; 35 mass% or less of a maleic anhydride-modified polyolefin resin; and 50 mass% or less of a polyamide resin and / or ethylene-vinyl alcohol copolymer.SELECTED DRAWING: None

Description

[Technical field]

[0001] The present invention relates to a film, a laminated film, a package, a recycled film, and a method for producing a laminated film. [Background technology]

[0002] In the fields of food packaging and medical packaging, a package (deep-drawn package) is used in which the contents are placed in a base material formed by hot-molding 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, films used as the base material for the deep-drawn package are laminated films of various resins, such as a seal layer that imparts heat sealability to the lid material, an ethylene-vinyl alcohol copolymer layer that imparts gas barrier properties, and a polyamide layer that imparts 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 discharged during production are returned to a portion of the polyolefin layer (recycled layer) and reused. [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 attempting to reuse a laminate film having a layer containing a polyamide resin or a layer containing an ethylene-vinyl alcohol copolymer (hereinafter sometimes referred to as "EVOH"), and a layer containing a polyolefin resin, the resulting film is a blend of different resins, which results in a significant decrease in transparency. This means that it is not possible to increase the amount of recycled raw materials added, and it is necessary to make the layer containing recycled raw materials thinner in order to ensure transparency, and this poses the problem that the recycling rate cannot be increased.

[0006] Therefore, the present invention aims to provide a film, a laminated film, and a method for producing a laminated film that are highly transparent and excellent in recyclability, and further excellent in thermal stability, even when they contain a polyolefin-based resin and a polyamide-based resin and / or EVOH, which are incompatible resins therewith. [Means for solving the problem]

[0007] Means for Solving the Problems The present inventors have conducted intensive research in light of the above-mentioned circumstances and have found that by adding a maleic anhydride modified polyolefin resin to a resin composition containing a polyolefin resin, a polyamide resin, and / or EVOH, the resin composition has good transparency, is excellent in recyclability, and is also excellent in thermal stability, even when the resin composition contains a polyolefin resin, a polyamide resin, and / or EVOH, and have thus completed the present invention.

[0008] That is, the gist of the present invention is the following [1] to

[15] . [1] A film having a layer formed from a resin composition containing 40% by mass or more of a polyolefin resin other than maleic anhydride-modified polyolefin resin, 35% by mass or less of a maleic anhydride-modified polyolefin resin, and 50% by mass or less of a polyamide resin and / or an ethylene-vinyl alcohol copolymer. [2] The film according to [1], wherein the maleic anhydride modified polyolefin resin is measured for an initial elastic modulus (G0) and an elastic modulus after 30 minutes (G30) using a rotational melt viscoelasticity measuring device (under a nitrogen atmosphere, at a temperature of 240°C, parallel plates of 25 mm in diameter, a frequency of 0.5 Hz, and a melting time of 30 minutes) based on JIS K7244-10 (2005), and the increase rate satisfies the following formula 1: Equation (1) [Elastic modulus after 30 minutes (G30)] / [Initial elastic modulus (G0)]≦180 [3] The film described in [1] or [2], wherein the resin composition contains recycled materials using the film as a starting material. [4] The film according to any one of [1] to [3], wherein the haze of the film is less than 30%. [5] A laminated film comprising at least four resin layers: a layer formed from a resin composition containing a polyamide resin, a layer formed from a resin composition containing EVOH, an intermediate layer, and an inner layer, the intermediate layer is formed from a resin composition containing a polyolefin resin other than a maleic anhydride-modified polyolefin resin, a maleic anhydride-modified polyolefin resin, and a polyamide resin and / or EVOH; The inner layer is formed from a resin composition containing a polyolefin resin as a main component. [6] The laminate film according to [5], wherein the resin composition forming the intermediate layer contains 40% by mass or more of a polyolefin resin other than maleic anhydride-modified polyolefin resin, 35% by mass or less of a maleic anhydride-modified polyolefin resin, and 50% by mass or less of a polyamide resin and / or EVOH. [7] The laminate film according to [5] or [6], wherein the maleic anhydride modified polyolefin resin is measured for an initial elastic modulus (G0) and an elastic modulus after 30 minutes (G30) using a rotational melt viscoelasticity measuring device (under a nitrogen atmosphere, at a temperature of 240°C, parallel plates of 25 mm in diameter, a frequency of 0.5 Hz, and a melting time of 30 minutes) based on JIS K7244-10 (2005), and the increase rate satisfies the following (Formula 1): Equation (1) [Elastic modulus after 30 minutes (G30)] / [Initial elastic modulus (G0)]≦180 [8] The laminate film according to any one of [5] to [7], wherein the intermediate layer contains recycled materials obtained by using the laminate film as a starting material. [9] The laminate film according to any one of [5] to [8], wherein the intermediate layer contains recycled materials made from a resin film containing a polyamide resin and / or EVOH.

[10] The laminate film according to any one of [5] to [9], wherein the intermediate layer has a haze of less than 30%.

[11] The laminate film according to any one of [5] to

[10] , which is for food packaging.

[12] The laminate film according to any one of [5] to

[10] , which is for deep drawing packaging.

[13] A packaging body using the laminate film according to any one of [5] to

[10] as a base material for deep drawing.

[14] A recycled film having at least one resin layer containing recycled materials, the resin layer being produced from the laminate film according to any one of [5] to

[10] .

[15] A method for producing a laminate film according to any one of [5] to

[10] , comprising the steps of: preparing a recycled raw material using the laminate film as a starting material; and co-extruding a resin composition containing the recycled raw material to obtain a laminate film having at least four resin layers, including a layer formed from a resin composition containing a polyamide resin, a layer formed from a resin composition containing EVOH, an intermediate layer, and an inner layer. Effect of the Invention

[0009] The film and laminated film of the present invention have good transparency, excellent recyclability, and further excellent thermal stability. 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 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 "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] 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] In addition, even if the upper and lower limits of the numerical ranges in this specification are slightly outside the numerical range 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 within the numerical range.

[0016] A film according to one embodiment of the present invention (hereinafter referred to as "the film") has a layer formed from a resin composition containing 40% by mass or more of a polyolefin resin excluding maleic anhydride modified polyolefin resin, 35% by mass or less of a maleic anhydride modified polyolefin resin, and 50% by mass or less of a polyamide resin and / or EVOH. Each component will be described below.

[0017] [Polyolefin resin] The polyolefin resin is excluding the maleic anhydride modified polyolefin resin described later, and examples thereof include polyethylene resin, polypropylene resin, etc. These may be used alone or in combination of two or more kinds.

[0018] (Polyethylene resin) Examples of the polyethylene resin include linear low density polyethylene (LLDPE), low density polyethylene (LDPE), medium density polyethylene (MDPE), high density polyethylene (HDPE), and resins obtained by modifying these polyethylene resins with unsaturated carboxylic acid or derivatives of unsaturated carboxylic acid. The polyethylene resin may contain an α-olefin unit. These may be used alone or in combination of two or more kinds. Among them, linear low density polyethylene is preferred.

[0019] Examples of the unsaturated carboxylic acid include acrylic acid, methacrylic acid, fumaric acid, crotonic acid, itaconic acid, citraconic acid, etc., and esters and anhydrides thereof. These may be used alone or in combination of two or more kinds.

[0020] 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 may be mentioned. These may be used alone or in combination of two or more kinds.

[0021] The α-olefin may, for example, be an α-olefin 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.

[0022] 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, and preferably 0.3 to 20 g / 10 min, from the viewpoint of film-forming properties.

[0023] (Polypropylene resin) Examples of the polypropylene resin include homopolypropylene, random copolymers and block copolymers of propylene and α-olefin, and resins obtained by modifying these polypropylene resins with unsaturated carboxylic acids or derivatives of unsaturated carboxylic acids, etc. These may be used alone or in combination of two or more kinds.

[0024] Examples of the unsaturated carboxylic acid and the derivative of the unsaturated carboxylic acid include the compounds exemplified in the description of the polyethylene resin.

[0025] The α-olefin may, for example, be an α-olefin 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.

[0026] 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, and preferably 0.3 to 20 g / 10 min, from the viewpoint of film-forming properties.

[0027] The melting point of the polyolefin 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.

[0028] The glass transition temperature of the polyolefin resin is usually 20° C. or lower, preferably 15° C. or lower, and 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., preferably −70° C., in view of its ease of availability as a general-purpose product.

[0029] The storage modulus E' of the polyolefin resin measured at a vibration frequency of 10 Hz and at 95°C is usually 1.0 × 10 6 ~1.0×10 9 Pa, preferably 1.5×10 6 ~9.0×10 8 Pa, more preferably 2.0×10 6 ~8.0×10 8By setting the storage modulus E' at 95°C within the above range, it is possible to impart extensibility and stiffness during deep drawing, and it is possible to prevent localized thinning due to uneven drawing, etc.

[0030] The storage modulus E' of the polyolefin resin measured at a vibration frequency of 10 Hz and at -20°C is usually 2.0 × 10 9 Pa or less, preferably 1.5×10 9 Pa or less, more preferably 1.0×10 9 By setting the storage modulus E' at -20°C to the above value or less, 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 Pa

[0031] The content of the polyolefin resin in the resin composition is 40% by mass or more, preferably 45% by mass or more, more preferably 50% by mass or more, from the viewpoint of transparency. The upper limit is not particularly limited, but is usually 95% by mass, preferably 90% by mass.

[0032] [Maleic anhydride modified polyolefin resin] The maleic anhydride-modified polyolefin resin is not particularly limited, and may be, for example, a copolymer of α-olefin and maleic anhydride, or a polyolefin resin graft-modified with maleic anhydride. The method for producing the maleic anhydride-modified polyolefin resin is also not particularly limited.

[0033] The α-olefin is not particularly limited, and examples thereof include ethylene, propylene, 1-butene, 1-hexene, 1-octene, vinyl esters such as vinyl acetate and vinyl benzoate, acrylic esters such as methyl acrylate and ethyl acrylate, methacrylic esters such as methyl methacrylate, ethyl methacrylate and glycidyl methacrylate, and unsaturated carboxylic acids such as acrylic acid and methacrylic acid, etc. These may be used alone or in combination of two or more kinds.

[0034] In terms of thermal stability, the maleic anhydride modified polyolefin resin preferably satisfies the following formula (1) in terms of the increase rate between the initial elastic modulus (G0) and the elastic modulus after 30 minutes (G30) measured under the following conditions using a rotary melt viscoelasticity measuring device based on JIS K7244-10 (2005): Formula (1) [Elastic modulus after 30 minutes (G30)] / [Initial elastic modulus (G0)]≦180 Furthermore, the increase rate is more preferably 140 or less, particularly preferably 100 or less, and especially preferably 60 or less.

[0035] The maleic anhydride-modified polyolefin resin has a maleic anhydride-modified amount of usually 0.3 mass% or more, preferably 0.4 to 2.0 mass%, and more preferably 0.5 to 1.5 mass%, based on 100 mass% of the maleic anhydride-modified polyolefin resin. By setting the maleic anhydride-modified amount within the above range, the thermal stability tends to be excellent.

[0036] The maleic anhydride modified polyolefin resin has a melt flow rate (MFR) (JIS K7210-1 Method A (2014), 190° C., load 2.16 kg) of usually 0.1 to 150 g / 10 min, and preferably 1 to 100 g / 10 min, from the viewpoint of film formability.

[0037] The content of the maleic anhydride modified polyolefin resin in the resin composition is 35% by mass or less, preferably 1 to 34% by mass, and more preferably 2 to 32% by mass. When the content of the maleic anhydride modified polyolefin resin is within the above range, a film having excellent transparency can be obtained. Maleic anhydride-modified polyolefin resins are usually used as adhesives (adhesive layers) for bonding resin layers together in laminated films. However, in the present invention, the maleic anhydride-modified polyolefin resins are not used as adhesives but as compatibilizers for compatibilizing polyolefin resins with incompatible polyamide resins and / or EVOH.

[0038] [Polyamide resin and / or EVOH] (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 and polyalkylene ether glycol. These may be used alone or in combination of two or more. Among them, aliphatic polyamides are preferred, and polyamide 6, polyamide 6,6, polyamide 11, and polyamide 12 are more preferred. Furthermore, polyamide 6 is more preferred because it also has impact resistance.

[0039] (EVOH) The EVOH is a resin obtained by saponifying a copolymer of ethylene and vinyl acetate with an alkali catalyst or the like.

[0040] 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.

[0041] The content of the polyamide resin and / or EVOH in the resin composition is 50% by mass or less, preferably 5 to 48% by mass, and more preferably 10 to 46% by mass. By setting the content of the polyamide resin and / or EVOH in the above range, the resin composition can have excellent transparency and thermal stability.

[0042] When the resin composition contains a polyamide resin and EVOH, the ratio [polyamide resin / EVOH] is usually 90 / 10 to 10 / 90, preferably 85 / 15 to 40 / 60, and more preferably 80 / 20 to 55 / 45, based on mass. When the ratio of polyamide resin to EVOH is within the above range, the transparency tends to be excellent.

[0043] [Additives] Furthermore, for the purpose of improving or adjusting various properties such as moldability and productivity, the resin composition 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, and antioxidants, 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 kinds.

[0044] [Recycled raw materials] In addition, in the present film, it is also preferable that the resin composition contains recycled raw materials made from scraps generated during the production process of the present film, the laminated film described below, deep-draw packaging, and the present film, other resin films, molded bodies, etc. In other words, it is preferable that a part or all of the polyolefin resin, maleic anhydride-modified polyolefin resin, polyamide resin, and EVOH contained in the present film are derived from recycled raw materials. In particular, from the standpoint of recyclability and transparency, it is preferable for the starting material to be recycled raw materials made from the present film, the laminate film described below, the packaging material, or scraps generated during the manufacturing process of the present film or the laminate film described below, and it is particularly preferable for the starting material to be recycled raw materials made from the present film or the laminate film described below. In addition, 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 polyamide resins and / or EVOH as starting materials.

[0045] 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 processed into fluff, repellet, etc. Among them, from the viewpoint of workability, it is preferable to use the film, packaging material, etc. after being processed into fluff or repellet.

[0046] 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.

[0047] 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, when the recycled raw materials contain polyolefin resins, maleic anhydride modified polyolefin resins, polyamide resins, and EVOH, these are included in the content of each resin.

[0048] [Method of manufacturing the present film] The present film can be produced using the resin composition by a known method, such as an extrusion lamination method, an extrusion inflation method, an extrusion T-die method, etc. The present film may be either a non-stretched film or a stretched film, but is usually a non-stretched film.

[0049] The film thus obtained has excellent transparency and thermal stability, even though it contains a polyolefin resin and a polyamide resin and / or EVOH, which are resins incompatible with the polyolefin resin.

[0050] The thickness of the present film is usually 10 to 100 μm, preferably 15 to 80 μm, and more preferably 20 to 60 μm. By setting the thickness of the present film within the above range, it tends to be possible to impart film formation stability, impact resistance, and deep draw formability.

[0051] <Internal haze> The internal haze of the present film is preferably less than 30%, more preferably 25% or less, from the viewpoints of visibility of contents, aesthetics, design, etc. The lower limit is not particularly limited, and a smaller value is preferable since transparency is good. The internal haze is a value measured based on JIS K7136 (2000).

[0052] The present film can be suitably used for various packages such as deep-draw packages, pouch packages, pillow packages, and vacuum packages, and as an intermediate layer in laminate films.

[0053] <Laminated film> A laminate film according to one embodiment of the present invention (hereinafter referred to as "the laminate film") is a laminate film consisting of at least four resin layers: a layer formed from a resin composition containing a polyamide-based resin (hereinafter sometimes referred to as "polyamide-based resin layer"), a layer formed from a resin composition containing EVOH (hereinafter sometimes referred to as "EVOH layer"), an intermediate layer, and an inner layer.

[0054] [Polyamide-based resin layer] The polyamide-based resin used in the polyamide-based resin layer includes the resins described above for the polyamide-based resin. Among them, aliphatic polyamides are preferred, and polyamide 6, polyamide 6,6, polyamide 11, and polyamide 12 are more preferred. Polyamide 6 is even more preferred because it also has impact resistance.

[0055] The resin composition forming the polyamide-based resin layer may contain the above-mentioned additives.

[0056] The resin composition forming the polyamide-based resin layer contains a polyamide-based 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.

[0057] The thickness of the polyamide-based resin 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 polyamide-based resin layer within the above range, film formation stability and deep drawability tend to be imparted.

[0058] [EVOH layer] The EVOH layer is used to enhance the gas barrier properties of the laminated film, and is preferably provided between the intermediate layer and the inner layer from the viewpoint of gas barrier properties. The EVOH used in the EVOH layer may be the resin described above for EVOH, and the preferred physical properties and the like are also as described above.

[0059] The resin composition forming the EVOH layer may contain the above-mentioned additives.

[0060] The resin composition forming the EVOH layer contains an EVOH 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.

[0061] The thickness of the EVOH 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 EVOH layer within the above range, film formation stability and sufficient gas barrier properties can be imparted, and deterioration of impact resistance and deep drawability can be suppressed.

[0062] [Middle class] The intermediate layer is formed from a resin composition containing a polyolefin resin other than maleic anhydride modified polyolefin resin, a maleic anhydride modified polyolefin resin, and a polyamide resin and / or EVOH.

[0063] The polyolefin resin, maleic anhydride modified polyolefin resin, polyamide resin, and EVOH may be those described above for the present film, and the preferred types, physical properties, etc. are also as described above.

[0064] In addition, the resin composition preferably contains 40% by mass or more of a polyolefin resin other than maleic anhydride-modified polyolefin resin, 35% by mass or less of a maleic anhydride-modified polyolefin resin, and 50% by mass or less of a polyamide resin and / or EVOH, from the viewpoint of excellent transparency, recyclability, and thermal stability.Moreover, it is more preferable that the contents of these polyolefin resins, maleic anhydride-modified polyolefin resins, polyamide resins, and EVOH are within the ranges of the contents explained for the present film.

[0065] The resin composition forming the intermediate layer may contain the above-mentioned additives.

[0066] [Inner layer] The inner layer 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. Furthermore, the inner layer is a layer that comes into contact with the contents when combined with a lid material to form a deep-draw package, and is preferably a heat-sealing layer that has heat-sealing properties with the lid material.

[0067] Examples of polyolefin resins used in the inner layer include ethylene-α-olefin copolymers, low-density polyethylene (LDPE), linear low-density polyethylene (LLDPE), 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), and resins obtained by modifying these polyolefin resins with the above-mentioned unsaturated carboxylic acids or their derivatives. These may be used alone or in combination of two or more.

[0068] 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.

[0069] The resin composition forming the inner layer 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 forming the inner layer within the above range, the heat sealability tends to be good.

[0070] The resin composition forming the inner layer may contain the above-mentioned additives.

[0071] The resin composition forming the inner 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.

[0072] The melting point of the resin composition forming the inner layer 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.

[0073] 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 property can be imparted.

[0074] The present laminate film is composed of at least four resin layers, namely, the polyamide layer, the EVOH layer, the intermediate layer, and the inner layer, and may have, in addition to the above-mentioned resin layers, an outer layer, an adhesive layer, an adjacent layer, etc. Also, the present laminate film may have two or more adhesive layers, adjacent layers, etc.

[0075] [Outer layer] The outer layer is provided for the purpose of improving formability, and can be provided within a range that does not impair the performance of the laminated film. The outer layer is preferably formed from a resin composition containing a polyolefin resin as a main component.

[0076] The polyolefin resin used in the resin composition forming the outer layer may be the polyolefin resin described in the present film, and the preferred physical properties thereof are also as described above.

[0077] The resin composition forming the outer layer may contain the above-mentioned additives.

[0078] 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.

[0079] 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 draw formability can be imparted.

[0080] [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. As the adhesive resin, a resin obtained by modifying the polyolefin resin described in the present film with an unsaturated carboxylic acid or its derivative, or the maleic anhydride modified polyolefin resin can be used. The adhesive resin may be used alone or in combination of two or more kinds.

[0081] The resin composition forming the adhesive layer may contain the above-mentioned additives.

[0082] The thickness of the adhesive resin 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 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 in the present laminated film.

[0083] [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.

[0084] The polyolefin resin may be the polyolefin resin described in the present film. 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.

[0085] The resin composition forming the adjacent layer may contain the above-mentioned additives.

[0086] The thickness of the adjacent 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, it tends to be possible to impart film formation stability. The thickness of the adjacent layer is the total thickness of all adjacent layers in the present laminate film.

[0087] [Recycled raw materials] In the present laminate film, it is preferable that at least one of the resin compositions forming each resin layer contains the above-mentioned recycled raw material.

[0088] 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 is preferably contained in the resin composition forming the outer layer, intermediate layer, adhesive layer, and adjacent layer in terms of maintaining the impact resistance, deep draw formability, sealability, transparency, gas barrier properties, etc. of the film. Among them, it is more preferable that the recycled raw material be contained in the resin composition forming the intermediate layer, adhesive layer, and adjacent layer, and it is particularly preferable that the recycled raw material be contained in the resin composition forming the intermediate layer and adjacent layer.

[0089] 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.

[0090] [Method of manufacturing the present laminated film] The present laminate film can be produced by a known method, such as extrusion lamination, coextrusion inflation, coextrusion T-die, etc., using a resin composition forming each resin layer. In particular, the coextrusion T-die method is preferably used, since the film-forming process is the same even when the number of layers of the film is large, and thickness control is relatively easy. In other words, the present laminate film is preferably a coextrusion laminate film. Furthermore, the present laminate film may be either a non-stretched film or a stretched film, but is usually a non-stretched film.

[0091] Examples of the structure of the laminated film are shown below, but the present invention is not limited to these. (1) Polyamide resin layer / adhesive layer / middle layer / adhesive layer / EVOH layer / adhesive layer / inner layer (2) Outer layer / adhesive layer / polyamide resin layer / adhesive layer / middle layer / adhesive layer / EVOH layer / adhesive layer / inner layer (3) Outer layer / adjacent layer / middle layer / adhesive layer / polyamide resin layer / adhesive layer / EVOH layer / adhesive layer / inner layer (4) Outer layer / adhesive layer / polyamide resin layer / adhesive layer / middle layer / adhesive layer / EVOH layer / adhesive layer / adjacent layer / inner layer

[0092] In addition, when the present laminate film has a resin layer formed from a resin composition containing recycled materials using the present film or the present laminate film as a starting material, the present laminate film can be obtained by a manufacturing method including a step of preparing the present film or recycled materials using the present laminate film as a starting material, and a step of co-extruding the resin composition containing the recycled materials to obtain a laminate film consisting of at least four resin layers: a polyamide layer, an intermediate layer, an EVOH layer, and an inner layer.

[0093] Examples of the recycled raw material in the process for producing the recycled raw material using the present film or the present laminate film as the starting raw material include fluff and repellets obtained from the present film or the present laminate film.

[0094] The method for obtaining fluff or repellets from the present film or laminate film can be a known method, for example, by subjecting the present film or laminate film to cutting, crushing, drying, melt-kneading, etc. These treatments may be performed alone or in combination of two or more.

[0095] In the process of co-extruding the resin composition containing the recycled raw material to obtain a laminated film consisting of at least four resin layers, i.e., a polyamide resin layer, an intermediate layer, an EVOH layer, and an inner layer, the laminated film may be produced by co-extruding the resin composition containing the present film, fluff obtained from the present laminated film, and repellets 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 laminated film, but it is preferable to form the intermediate layer, adjacent layer, or adhesive layer, and it is particularly preferable to form the intermediate layer or adjacent layer.

[0096] <This laminated film> The laminated film thus obtained is composed of at least four resin layers, namely, a polyamide resin layer, an intermediate layer, an EVOH layer, and an inner layer.

[0097] The thickness of the laminated 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, the film tends to have deep drawability and a thickness that is practically problem-free after deep drawing, and mechanical strength and heat resistance can be imparted. By making the thickness less than 300 μm, the film tends to have deep drawability and cost reduction.

[0098] The internal haze value calculated from the total light transmittance and diffuse transmittance of this laminated film measured according to JIS K7136 (2000) is preferably 25% or less, more preferably 20% or less, and even more preferably 16% or less, from the viewpoint of visibility of contents.

[0099] The puncture energy of the laminated film measured at 23°C according to JIS K7124-2 (1999) using a hydroshot high-speed tester is preferably 0.70 J or more, more preferably 0.80 J or more. The puncture displacement is preferably 19 mm or more, more preferably 22 mm or more. By keeping the puncture energy and puncture displacement at 23°C within the above ranges, the film tends to be less susceptible to breakage or pinholes even when subjected to shocks during packaging of contents, for example, during transportation.

[0100] The puncture energy of the laminated film measured at 5°C according to JIS K7124-2 (1999) using a hydroshot high-speed tester is preferably 0.70 J or more, more preferably 0.80 J or more. The puncture displacement is preferably 16 mm or more, more preferably 18 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 in a refrigerator.

[0101] The puncture energy of the laminated film measured at -20°C according to JIS K7124-2 (1999) using a hydroshot high-speed tester is preferably 0.4 J or more, more preferably 0.6 J or more, and even more preferably 0.8 J or more. The puncture displacement is preferably 8 mm or more, more preferably 12 mm or more, and even more preferably 14 mm or more. By keeping 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.

[0102] In addition, when the thickness of this laminated film is 100 μm, the gas permeability 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.

[0103] <Package> The present laminate 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 laminate film is preferably used for deep-draw packaging. In addition, the deep drawing package preferably uses the present laminate film as a deep drawing base material.

[0104] When the present laminated film is used for deep drawing packaging, particularly as a base material for deep drawing, it is preferable to produce it without stretching in order to improve formability during drawing. In addition, when the laminated film is to be packaged in a pouch, pillowcase, or vacuum, it is preferable to produce the laminated film without stretching it, and then further laminate a stretched film such as a biaxially oriented polypropylene film by a dry lamination method or the like, from the viewpoint of imparting strength and gas barrier properties.

[0105] <Recycled film> Since the present film and the present laminate film are highly transparent, they can be suitably used as recycled materials. Therefore, recycled films (resin layers) may be produced using recycled materials that start from the present film or the present laminate film. The recycled 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. EXAMPLES

[0106] 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.

[0107] Prior to the examples, the following raw materials were prepared. The thermal stability (increase rate) of the maleic anhydride modified polyolefin resin was measured by the method described below.

[0108] [Polyolefin resin] PO: Ultzekkus 2021L [Prime Polymer, LLDPE, MFR (190℃, load 2.16kg) 2.1g / 10min]

[0109] [Maleic anhydride modified polyolefin resin] · MAPO1: ADMER SF730 [Mitsui Chemicals, maleic anhydride modified polyolefin, maleic anhydride modification amount 0.9 mass%, MFR (190°C, load 2.16 kg) 2.7 g / 10 min, increase rate 5] MAPO2: DPA 41710 (Dow Chemical Company, maleic anhydride modified polyolefin, maleic anhydride modification amount 0.7 mass%, MFR (190°C, load 2.16 kg) 2.7 g / 10 min, increase rate 15) MAPO3: Rexpearl ET720X (Japan Polyethylene Corporation, maleic anhydride modified polyolefin, maleic anhydride modification amount 1.3 mass%, MFR (190°C, load 2.16 kg) 80g / 10min, increase rate 50) · MAPO4: RETAIN 3000 (Dow Chemical Company, maleic anhydride modified polyolefin, maleic anhydride modification amount 2.8 mass%, MFR (190°C, load 2.16 kg) 600g / 10min, increase rate 150)

[0110] [Polyamide resin] PA: UBE1030B (UBE, polyamide 6, 98% sulfuric acid relative viscosity 4.08)

[0111] [EVOH] EVOH: SoarnoL DC3203RB (Mitsubishi Chemical Corporation, ethylene-vinyl alcohol copolymer, ethylene content 32 mol%, MFR 3.0 g / 10 min, 210°C, load 2.16 kg)

[0112] [Thermal stability] The maleic anhydride modified polyolefin resin was measured for initial elastic modulus (G0) and elastic modulus after 30 minutes (G30) using a rotary melt viscoelasticity measuring device (parallel plates with a diameter of 25 mm at a temperature of 240°C under nitrogen atmosphere, frequency of 0.5Hz, melting time of 30 minutes) using a rheometer (manufactured by TA Instruments, "DiscoveryHR2") in accordance with JIS K7244-10 (2005). The increase rate of melt elastic modulus (G30 / G0) was calculated from the following formula (1) and evaluated according to the following criteria. The results are shown in Table 1 below. Equation (1) [Elastic modulus after 30 minutes (G30)] / [Initial elastic modulus (G0)] [Evaluation Criteria] ○: G30 / G0 is 100 or less △: G30 / G0 is over 100 and under 180 ×: G30 / G0 is over 180

[0113] <Examples 1 to 12 and Comparative Examples 1 and 2> The raw materials were mixed in a plastic bag so as to obtain the composition shown in Tables 1 and 2 below, melt-kneaded at 240°C, and extruded from a die at 240°C to produce a film with a thickness of 100 μm.

[0114] The transparency was evaluated for the films of Examples 1 to 12 and Comparative Examples 1 and 2. The results are shown in Tables 1 and 2 below.

[0115] [Transparency] The film surface 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. [Evaluation Criteria] ○: Internal haze is less than 30% ×: Internal haze is 30% or more

[0116] 〔comprehensive evaluation〕 The thermal stability and transparency were evaluated according to the following criteria. [Evaluation Criteria] ○: Both thermal stability and transparency are rated as "○" △: Thermal stability is rated as "△", transparency is rated as "○" ×: Either the thermal stability or the transparency was evaluated as "×".

[0117] [Table 1]

[0118] [Table 2]

[0119] Although the films of Examples 1 to 12 contain a polyolefin resin, a polyamide resin incompatible with the polyolefin resin, and EVOH, they can be stably formed and have excellent transparency. In addition, since the maleic anhydride-modified polyolefin resin contained therein has excellent thermal stability, they also have excellent long-term running properties. On the other hand, the film of Comparative Example 1, which did not contain maleic anhydride-modified polyolefin resin, had poor compatibility with the polyolefin resin, polyamide resin, and EVOH, and was poor in transparency. Also, the film of Comparative Example 2, which contained too little polyolefin resin, could not be produced.

[0120] Furthermore, since the films of Examples 1 to 12 are excellent in transparency and thermal stability, when a laminate film is produced using the films of Examples 1 to 12 as an intermediate layer and further comprising at least four resin layers, a polyamide resin layer, an EVOH layer, and an inner layer, the laminate film has excellent transparency and thermal stability. [Industrial Applicability]

[0121] The present film has excellent transparency and thermal stability and can therefore be suitably used as an intermediate layer in deep drawing packaging films.

Claims

1. The film has a layer formed from a resin composition containing 40% by mass or more of a polyolefin resin other than maleic anhydride-modified polyolefin resin, 35% by mass or less of a maleic anhydride-modified polyolefin resin, and 50% by mass or less of a polyamide resin and / or an ethylene-vinyl alcohol copolymer.

2. The maleic anhydride-modified polyolefin resin has an initial elastic modulus (G0) and an elastic modulus after 30 minutes (G30) measured using a rotary melt viscoelasticity measuring device (under a nitrogen atmosphere, at a temperature of 240° C., parallel plates having a diameter of 25 mm, a frequency of 0.5 Hz, and a melting time of 30 minutes) according to JIS K7244-10 (2005), and the increase rate satisfies the following (Formula 1): Equation (1) [Elastic modulus after 30 minutes (G30)] / [Initial elastic modulus (G0)]≦180

3. The film according to claim 1 or 2, wherein the resin composition comprises a recycled material obtained by using the film as a starting material.

4. 3. The film of claim 1 or 2, wherein the haze of the film is less than 30%.

5. A laminated film comprising at least four resin layers, including a layer formed from a resin composition containing a polyamide resin, a layer formed from a resin composition containing an ethylene-vinyl alcohol copolymer, an intermediate layer, and an inner layer, the intermediate layer is formed from a resin composition containing a polyolefin resin other than a maleic anhydride-modified polyolefin resin, a maleic anhydride-modified polyolefin resin, and a polyamide resin and / or an ethylene-vinyl alcohol copolymer; The inner layer is formed from a resin composition containing a polyolefin resin as a main component.

6. The resin composition forming the intermediate layer contains 40% by mass or more of a polyolefin resin other than maleic anhydride-modified polyolefin resin, 35% by mass or less of a maleic anhydride-modified polyolefin resin, and 50% by mass or less of a polyamide resin and / or an ethylene-vinyl alcohol copolymer. The laminate film according to claim 5.

7. The maleic anhydride-modified polyolefin resin has an initial elastic modulus (G0) and an elastic modulus after 30 minutes (G30) measured using a rotary melt viscoelasticity measuring device (under a nitrogen atmosphere, at a temperature of 240° C., parallel plates having a diameter of 25 mm, a frequency of 0.5 Hz, and a melting time of 30 minutes) based on JIS K7244-10 (2005), and the increase rate satisfies the following (Formula 1): Equation (1) [Elastic modulus after 30 minutes (G30)] / [Initial elastic modulus (G0)]≦180

8. The laminate film according to claim 5 or 6, wherein the intermediate layer contains recycled material produced from the laminate film as a starting material.

9. The laminate film according to claim 5 or 6, wherein the intermediate layer contains a recycled material obtained by using a resin film containing a polyamide resin and / or an ethylene-vinyl alcohol copolymer as a starting material.

10. 7. The laminate film according to claim 5 or 6, wherein the haze of the intermediate layer is less than 30%.

11. The laminated film according to claim 5 or 6, which is for food packaging.

12. The laminated film according to claim 5 or 6, which is for deep drawing packaging.

13. A package comprising the laminated film according to claim 5 or 6 as a base material for deep drawing.

14. A recycled film having at least one resin layer containing recycled materials produced by using the laminate film according to claim 5 or 6 as a starting material.

15. 7. A method for producing the laminated film according to claim 5 or 6, comprising the steps of: preparing a recycled raw material using the laminated film as a starting material; and co-extruding a resin composition containing the recycled raw material to obtain a laminated film having at least four resin layers, including a layer formed from a resin composition containing a polyamide resin, a layer formed from a resin composition containing an ethylene-vinyl alcohol copolymer, an intermediate layer, and an inner layer.

Images