Stretched film, laminate and packaging bag

Abstract

To provide a stretched polyolefin film which not only achieves both recyclability and desirable performance such as mechanical strength and transparency as a film but also has excellent stretching performance and to provide a laminate using the stretched film and a packaging bag using the laminate.SOLUTION: There is provided a stretched film having an intermediate layer and a skin layer formed on one surface or both surfaces of the intermediate layer, which satisfies the following requirements (1) and (2). Requirement (1): the intermediate layer contains an ethylene-based polymer (A) and a propylene-based polymer (B). Requirement (2): the skin layer contains a propylene-based polymer (C).SELECTED DRAWING: None

Description

[Technical field]

[0001] The present invention relates to stretched films, laminates, and packages. [Background technology]

[0002] As a packaging material, a laminate comprising a base film and a sealant film is known. For the base film, a stretched film tends to be used from the viewpoint of mechanical strength such as rigidity. For example, Patent Document 1 describes a laminate comprising a biaxially stretched polyethylene terephthalate (PET) film as the base film and a polyolefin film such as polyethylene (PE) or polypropylene (PP) as the sealant film.

[0003] On the other hand, from the viewpoint of reducing environmental load, etc., packaging materials with high recyclability are required. In recycling, it is preferable that the plastic material is a so-called monomaterial, which is composed of a single type of polymer. Therefore, it is preferable to use a base film, a sealant film, and a laminate mainly composed of an ethylene-based polymer or a propylene-based polymer. However, a film composed only of an ethylene-based polymer does not necessarily have excellent stretchability, and a solution to this problem has been studied.

[0004] For example, in Patent Document 2, the degree of crosslinking of a PE resin sheet is changed in the thickness direction to improve stretchability, particularly at low temperatures. However, the production of a film with a degree of crosslinking changed in the thickness direction complicates the process and is disadvantageous in terms of cost, and crosslinking is also undesirable from the viewpoint of recyclability. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] JP 2017-178357 A [Patent Document 2] Japanese Patent Application Publication No. 61-74819 Summary of the Invention [Problem to be solved by the invention]

[0006] An object of the present invention is to provide a stretched polyolefin film which not only combines recyclability with favorable film properties such as mechanical strength and transparency, but also has excellent stretching performance, as well as a laminate using this stretched film and a packaging product such as a packaging bag using this laminate. [Means for solving the problem]

[0007] The present invention relates to the following items [1] to [9]. [1] A stretched film having an intermediate layer and a skin layer formed on one or both sides of the intermediate layer, the stretched film satisfying the following requirements (1) and (2): Requirement (1): the intermediate layer contains an ethylene-based polymer (A) and a propylene-based polymer (B); Requirement (2): The skin layer contains a propylene-based polymer (C). [2] The propylene-based polymer (B) of the intermediate layer is Requirement (b1) The melting point measured by DSC is less than 120°C or no melting point is observed. Requirement (b2) 51 to 90 mol % of structural units derived from propylene; 7 to 24 mol % of ethylene-derived structural units, and Contains 3 to 25 mol% of structural units derived from α-olefins having 4 to 20 carbon atoms Propylene-ethylene-α-olefin copolymer that satisfies the requirements (wherein the total of the structural units derived from propylene, the structural units derived from ethylene, and the structural units derived from an α-olefin having 4 to 20 carbon atoms is taken as 100 mol %). [3] The stretched film according to either [1] or [2], wherein the propylene-based polymer (B) of the intermediate layer contains one or more propylene-α-olefin copolymers selected from the group consisting of propylene-ethylene copolymers and propylene-1-butene copolymers. [4] The stretched film according to any one of [1] to [3], wherein the skin layer contains 3 to 40% by mass of an ethylene-based polymer (D) (wherein the total of the propylene-based polymer (C) and the ethylene-based polymer (D) is 100% by mass). [5] The stretched film according to any one of [1] to [4], which is stretched 2 to 8 times in the longitudinal direction and 2 to 16 times in the transverse direction. [6] A laminate comprising the stretched film according to any one of [1] to [5] and a sealant film layer. [7] The laminate according to [6], wherein the sealant film layer comprises an ethylene-based polymer (E). [8] The laminate according to [6] or [7], further comprising at least one functional material layer selected from a printing layer, a barrier layer and an embossed layer, and the functional material layer is adjacent to or in contact with, via an adhesive layer, at least one layer selected from the intermediate layer, the skin layer and the sealant film layer. [9] A packaging material comprising the laminate according to any one of [6] to [9]. Effect of the Invention

[0008] The stretched film of the present invention uses a resin composition containing a specific ethylene-based polymer and a propylene-based polymer in a prescribed ratio for the intermediate layer and a polypropylene resin for the skin layer, thereby obtaining a stretched polyolefin film with excellent stretchability and improved adhesive strength between the layers.

[0009] In addition, a laminate using the stretched film of the present invention can exhibit excellent performance in that it has excellent interlayer adhesion with the sealant film layer, resulting in excellent heat seal strength of the sealant film layer and being less susceptible to reduction in heat seal strength due to peeling (delamination). DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0010] [Stretched film] The stretched film of the present invention has an intermediate layer and a skin layer formed on one or both sides of the intermediate layer.

[0011] <Middle Class> The intermediate layer is made of a resin composition containing an ethylene-based polymer (A) and a propylene-based polymer (B). The resin composition constituting the intermediate layer in the present invention suitably contains 50 to 97% by mass of an ethylene-based polymer (A) and 3 to 50% by mass of a propylene-based polymer (B). More preferably, the composition contains 60 to 95 mass% of the ethylene polymer (A) and 5 to 40 mass% of the propylene polymer (B) (provided that the total of the ethylene polymer (A) and the propylene polymer (B) is 100 mass%).

[0012] <Ethylene-based polymer (A)> The ethylene-based polymer (A) contains more than 50 mol % of structural units derived from ethylene, and examples thereof include ethylene homopolymers, copolymers containing ethylene as a main monomer and at least one α-olefin having 3 or more carbon atoms, preferably 3 to 20 carbon atoms, ethylene-vinyl acetate copolymers, saponification products thereof, and ionomers.

[0013] Specifically, examples of the copolymer include copolymers of ethylene as a main monomer and at least one α-olefin having 3 to 20 carbon atoms, such as polyethylene, ethylene-propylene copolymer, ethylene-1-butene copolymer, ethylene-1-pentene copolymer, ethylene-1-hexene copolymer, ethylene-4-methyl-1-pentene copolymer, and ethylene-1-octene copolymer. The content of these α-olefins is preferably 0.1 to 15 mol%, more preferably 0.5 to 10 mol%, provided that the total of the ethylene content and the α-olefin content is 100 mol%.

[0014] The proportion of structural units derived from ethylene in the ethylene-based polymer (A) exceeds 50 mol %, which distinguishes it from the propylene-based polymer (B) described below. The ethylene polymer (A) may be one type of polymer, or two or more types of polymers.

[0015] The density (ASTM D 1505) of the ethylene polymer (A) according to the present invention is preferably 900 to 970 kg / m 3 and more preferably 930 to 965 kg / m 3 It is.

[0016] Density 900kg / m 3 The rigidity is improved by the density being 970kg / m or more. 3 By satisfying the above condition, the stretchability, toughness and transparency are improved. The melt flow rate (ASTM D1238, 190°C, 2.1 kg load) of the ethylene polymer (A) is preferably 0.1 to 15 g / 10 min, more preferably 0.5 to 10 g / 10 min, and further preferably 1.0 to 5.0 g / 10 min. If the melt flow rate is within this range, molding can be performed at a high molding speed using an existing molding machine, and molding stability is improved, which is preferable.

[0017] Specific examples of the ethylene polymer (A) include ethylene polymers manufactured and sold under the name of polyethylene. Specifically, high-pressure low-density polyethylene (LDPE), linear low-density polyethylene (LLDPE), and high-density polyethylene (HDPE) are preferred, and linear low-density polyethylene and high-density polyethylene are more preferred.

[0018] High Density Polyethylene The high density polyethylene (HDPE) preferably used as the ethylene polymer (A) may be an ethylene homopolymer or a copolymer of ethylene and an α-olefin.

[0019] The density of high density polyethylene (ASTM D 1505) is 940-970 kg / m 3 is preferable, and more preferably 940 to 965 kg / m 3 The density is 970kg / m 3 By satisfying the above condition, the stretchability, toughness and transparency are improved.

[0020] A commercially available high-density polyethylene that is preferably used is, for example, Hi-Zex 3300F (MFR=1.1 g / 10 min, density=950 kg / m 3 (manufactured by Prime Polymer Co., Ltd.).

[0021] High density polyethylene can be produced by homopolymerizing ethylene or copolymerizing ethylene and an α-olefin having 3 to 20 carbon atoms in the presence of a known catalyst such as a Ziegler-Natta catalyst by a known polymerization method such as a gas phase method, a solution method, a bulk method, or a slurry method. Specific examples of the α-olefin having 3 to 20 carbon atoms include propylene, 1-butene, 1-hexene, 1-heptene, 1-octene, 1-decene, 1-undecene, 3-methyl-1-butene, 3-methyl-1-pentene, 4-methyl-1-pentene, 4-methyl-1-hexene, and 4,4-dimethyl-1-hexene. These may be used alone or in combination of two or more. In addition, the ethylene and the α-olefin may be derived from biomass or fossil fuel, or both a biomass-derived monomer and a fossil fuel-derived monomer may be used.

[0022] Linear low density polyethylene The density of linear low density polyethylene (ASTM D 1505) is 900-940 kg / m 3 is preferable, and more preferably 930 to 940 kg / m 3 The density is 900kg / m 3 As a result, the rigidity is improved.

[0023] A commercially available high-density polyethylene that is preferably used is, for example, EVOLU SP4020 (MFR=1.8g / 10min, density=936kg / m 3 (manufactured by Prime Polymer Co., Ltd.).

[0024] The linear low density polyethylene can be produced by copolymerizing ethylene and an α-olefin having 3 to 20 carbon atoms in the presence of a conventionally known catalyst, such as a multi-site catalyst, such as a Ziegler catalyst, or a single-site catalyst, such as a metallocene catalyst, by a known polymerization method, such as a gas phase method, a solution method, a bulk method, or a slurry method. Specific examples of the α-olefin having 3 to 20 carbon atoms include propylene, 1-butene, 1-hexene, 1-heptene, 1-octene, 1-decene, 1-undecene, 3-methyl-1-butene, 3-methyl-1-pentene, 4-methyl-1-pentene, 4-methyl-1-hexene, and 4,4-dimethyl-1-hexene. These may be used alone or in combination of two or more. In addition, the ethylene and the α-olefin may be derived from biomass or fossil fuel, or both a biomass-derived monomer and a fossil fuel-derived monomer may be used.

[0025] <Propylene-based polymer (B)> The propylene polymer (B) contains more than 50 mol% of structural units derived from propylene, and examples thereof include a propylene homopolymer, a copolymer in which propylene is the main monomer and at least one α-olefin (excluding propylene) having 2 or more carbon atoms, preferably 2 to 20 carbon atoms, etc. Specific examples thereof include copolymers in which propylene is the main monomer and at least one α-olefin having 2 to 20 carbon atoms, such as a propylene-ethylene copolymer, a propylene-1-butene copolymer, and a propylene-ethylene-1-butene copolymer.

[0026] The proportion of the α-olefin in these copolymers is preferably 10 to 49 mol %, more preferably 20 to 35 mol %, provided that the total of the propylene content and the α-olefin content is 100 mol %.

[0027] The proportion of structural units derived from propylene in the propylene-based polymer (B) exceeds 50 mol %, and in this respect the propylene-based polymer (B) is distinguished from the ethylene-based polymer (A). The propylene polymer (B) may be one type of polymer or two or more types of polymers.

[0028] The melt flow rate (ASTM D1238, 230°C, 2.1 kg load) of the propylene polymer (B) is preferably 0.1 to 15 g / 10 min, more preferably 0.5 to 15 g / 10 min. If the melt flow rate is within this range, molding can be performed at a high molding speed using an existing molding machine, and molding stability is improved, which is preferable.

[0029] As the propylene polymer (B), a propylene-ethylene copolymer or a propylene-ethylene-α-olefin copolymer is preferred. Since these copolymers contain ethylene, they have excellent flexibility and can improve the interlayer strength between the intermediate layer and the skin layer. The propylene-ethylene-α-olefin copolymer preferably satisfies the following requirements (b1) and (b2), more preferably further satisfies the following requirements (b3) to (b5), and even more preferably further satisfies the following requirements (b6) to (b7).

[0030] Requirement (b1) The melting point (Tm) measured by differential scanning calorimetry (DSC) is less than 120°C, or no melting point is observed by differential scanning calorimetry (DSC). It is preferred that the melting point (Tm) is below 100° C., or that no melting point is observed.

[0031] Here, "no melting point is observed" means that no crystal melting peak with a crystal melting heat of 1 J / g or more is observed in the range of -150 to 200° C. by differential scanning calorimetry (DSC). The melting point is the melting point detected on a DSC curve obtained by conditioning a test specimen at 23° C.±2° C. for 72 hours or more, cooling it to -40° C., and then measuring it at a heating rate of 10° C. / min.

[0032] From the viewpoints of both flexibility and compatibility with the propylene-based copolymer (C) constituting the skin layer, the propylene-based polymer (B) is preferably a terpolymer of propylene, ethylene, and an α-olefin having 4 to 20 carbon atoms, and more specifically, satisfies the following requirement (b2).

[0033] Requirement (b2) The copolymer contains 51 to 90 mol % of structural units derived from propylene, 7 to 24 mol % of structural units derived from ethylene, and 3 to 25 mol % of structural units derived from an α-olefin having 4 to 20 carbon atoms.

[0034] This range preferably includes 60 to 85 mol % of structural units derived from propylene, 10 to 20 mol % of structural units derived from ethylene, and 3 to 23 mol % of structural units derived from an α-olefin having 4 to 20 carbon atoms, and more preferably includes 65 to 80 mol % of structural units derived from propylene, 11 to 19 mol % of structural units derived from ethylene, and 4 to 21 mol % of structural units derived from an α-olefin having 4 to 20 carbon atoms (here, the total of the structural units derived from propylene, the structural units derived from ethylene, and the structural units derived from an α-olefin having 4 to 20 carbon atoms is 100 mol %). As the α-olefin having 4 to 20 carbon atoms, 1-butene, 1-hexene, 1-octene, or 1-decene is preferred due to its easy availability, and 1-butene is particularly preferred.

[0035] Requirement (b3) Shore A hardness is in the range of 20 to 90. It is preferable from the viewpoint of flexibility that the Shore A hardness is within this range. The Shore A hardness is more preferably within the range of 20 to 90, further preferably within the range of 23 to 85, and particularly preferably within the range of 25 to 80. The Shore A hardness is a value obtained by heating and melting the propylene polymer (B) at 190 to 230°C, and then press-molding the resulting specimen at a cooling temperature of 15 to 25°C, storing the specimen in an environment of 23°C ± 2°C for 72 hours or more, and then using an A-type measuring instrument to read the scale immediately after the indenter comes into contact with the specimen (in accordance with ASTM D-2240).

[0036] Requirement (b4): The ratio (Mw / Mn) of the weight average molecular weight (Mw) to the number average molecular weight (Mn) (molecular weight distribution) measured by gel permeation chromatography (GPC) is 1.2 to 3.5.

[0037] This ratio (Mw / Mn) is preferably 1.5 to 2.9, and more preferably 1.8 to 2.4. Such a molecular weight distribution is preferable in that the amount of low molecular weight components is small, thereby suppressing sticky feeling. The weight average molecular weight (Mw) and number average molecular weight (Mn) are values ​​obtained by gel permeation chromatography (GPC) in terms of polystyrene.

[0038] Requirements (b5) 13 The isotactic triad fraction (mm) calculated by C-NMR is 85 to 99.9%. The isotactic triad fraction (mm) is preferably 85 to 97.5%, particularly preferably 90 to 97%. When the isotactic triad fraction (mm) is in this range, even if a large amount of comonomer such as ethylene or 1-butene is copolymerized, the crystallinity is not completely lost, which is preferable in the present invention from the viewpoint of mechanical properties, etc. The isotactic triad fraction (mm) can be measured using the method described in WO2004-087775, pamphlet, from page 21, line 7 to page 26, line 6.

[0039] Requirement (b6) The glass transition temperature (Tg) is observed in the range of -50°C to -10°C by differential scanning calorimetry (DSC). It is preferable from the viewpoint of mechanical properties at low temperatures that the glass transition temperature (Tg) is within this range. The glass transition temperature (Tg) can be determined by a differential scanning calorimeter (DSC) under the conditions described in the above requirement (b1).

[0040] Requirement (b7) MFR (ASTM D1238, 230°C, 2.16 kg load) is 0.5 to 500 g / 10 min. From the viewpoints of processability and mechanical properties, it is preferable for the MFR to be within this range. The MFR is preferably 1 to 100 g / 10 min, more preferably 2 to 50 g / 10 min, further preferably 3 to 30 g / 10 min, and particularly preferably 4 to 20 g / 10 min.

[0041] The propylene polymer (B) can be produced by homopolymerizing propylene or copolymerizing propylene and an α-olefin having 2 to 20 carbon atoms (excluding propylene) in the presence of a known catalyst such as a Ziegler-Natta catalyst or a metallocene catalyst by a known polymerization method such as a gas phase method, a solution method, a bulk method, or a slurry method. Specific examples of the α-olefin having 2 to 20 carbon atoms include ethylene, 1-butene, 1-hexene, 1-heptene, 1-octene, 1-decene, 1-undecene, 3-methyl-1-butene, 3-methyl-1-pentene, 4-methyl-1-pentene, 4-methyl-1-hexene, and 4,4-dimethyl-1-hexene. These may be used alone or in combination of two or more. In addition, propylene and α-olefin may be derived from biomass or fossil fuel, or both biomass-derived monomers and fossil fuel-derived monomers may be used.

[0042] The intermediate layer may contain additives, such as a resin other than the ethylene polymer (A) and the propylene polymer (B), a tackifier, a weather stabilizer, a heat stabilizer, an antistatic agent, a slip agent, an antiblocking agent, a lubricant, a pigment, a dye, a plasticizer, an antioxidant, a hydrochloric acid absorber, and an antioxidant, as necessary, within the scope of the object of the present invention. The intermediate layer may consist of one layer or multiple layers.

[0043] <Skin layer> The skin layer is made of a resin composition containing a propylene-based polymer (C). The resin composition constituting the skin layer preferably contains an ethylene-based polymer (D) together with the propylene-based polymer (C). The resin composition of the skin layer preferably contains 60 to 97% by mass of the propylene-based polymer (C) and 3 to 40% by mass of the ethylene-based polymer (D) (wherein the total of the propylene-based polymer (C) and the ethylene-based polymer (D) is 100% by mass).

[0044] <Propylene-based polymer (C)> The propylene-based polymer (C) constituting the skin layer of the present invention contains more than 50 mol% of structural units derived from propylene, and examples thereof include homopolymers of propylene, copolymers of propylene as the main monomer with at least one α-olefin having 2 or more carbon atoms, preferably 2 to 20 carbon atoms (excluding propylene), and diene compounds. In the case of copolymers, they may be random copolymers or block copolymers. Specific examples include copolymers of propylene as the main monomer with at least one α-olefin having 2 to 20 carbon atoms, such as propylene-ethylene copolymers, propylene-1-butene copolymers, and propylene-ethylene-1-butene copolymers. The proportion of α-olefins in these copolymers is preferably 0 to 15 mol%, more preferably 0.5 to 10 mol%. However, the total of the propylene content and the α-olefin content is 100 mol%. The propylene-based polymer (C) may be one type of polymer, or two or more types of polymers.

[0045] The propylene polymer (C) has an MFR of preferably 0.1 to 30 g / 10 min, more preferably 0.5 to 20 g / 10 min, measured in accordance with ASTM D1238 at 230°C under a load of 2.16 kg, and a melting point (Tm) of preferably 120 to 165°C, more preferably 135 to 165°C.

[0046] The propylene polymer (C) can be produced by polymerizing a monomer by a known polymerization method such as a gas phase method, a bulk method, or a slurry method in the presence of a known catalyst such as a Ziegler-Natta catalyst or a metallocene catalyst. The monomer may be derived from biomass or may be derived from fossil fuel. In addition, both a biomass-derived monomer and a fossil fuel-derived monomer may be used.

[0047] <Ethylene-based polymer (D)> The ethylene-based polymer (D) contains more than 50 mol% of ethylene-derived structural units, and examples thereof include copolymers of ethylene as a main monomer with at least one α-olefin having 3 or more carbon atoms, preferably 3 to 20 carbon atoms, ethylene-vinyl acetate copolymers, saponified products thereof, and ionomers thereof. Specific examples include copolymers of ethylene as a main monomer with at least one α-olefin having 3 to 20 carbon atoms, such as polyethylene, ethylene-propylene copolymer, ethylene-1-butene copolymer, ethylene-1-pentene copolymer, ethylene-1-hexene copolymer, ethylene-4-methyl-1-pentene copolymer, and ethylene-1-octene copolymer. The α-olefin content of these is preferably 2 to 20 mol%, more preferably 5 to 15 mol%. However, the total of the ethylene content and the α-olefin content is 100 mol%.

[0048] The density of the ethylene polymer (D) (ASTM D 1505) is 870 to 900 kg / m 3 is preferable, and more preferably 875 to 895 kg / m 3 The density is 875 kg / m 3 By setting the density to 900 kg / m or more, the surface properties such as slip resistance and blocking resistance are improved. 3 When the thickness is equal to or less than 100 mm, the flexibility is excellent and the interlayer strength between the intermediate layer and the skin layer can be improved.

[0049] The melt flow rate (ASTM D1238, 190°C, 2.1 kg load) of the ethylene polymer (D) is preferably 0.1 to 15 g / 10 min, more preferably 0.5 to 10 g / 10 min, and further preferably 1.0 to 5.0 g / 10 min. If the melt flow rate is within this range, molding can be performed at a high molding speed using an existing molding machine, and molding stability is improved, which is preferable.

[0050] The ethylene polymer (D) can be produced by copolymerizing ethylene and an α-olefin in the presence of a conventionally known catalyst, such as a multi-site catalyst, such as a Ziegler catalyst, or a single-site catalyst, such as a metallocene catalyst, by a known polymerization method, such as a gas phase method, a solution method, a bulk method, or a slurry method. The α-olefin is an α-olefin having 3 to 20 carbon atoms, and examples thereof include propylene, 1-butene, 1-hexene, 1-heptene, 1-octene, 1-decene, 1-undecene, 3-methyl-1-butene, 3-methyl-1-pentene, 4-methyl-1-pentene, 4-methyl-1-hexene, and 4,4-dimethyl-1-hexene. These may be used alone or in combination of two or more. In addition, the ethylene and the α-olefin may be derived from biomass or fossil fuel, or both a biomass-derived monomer and a fossil fuel-derived monomer may be used.

[0051] In addition to the propylene-based polymer (C), the skin layer may contain additives such as the ethylene-based polymer (D), other resins, tackifiers, weather stabilizers, heat stabilizers, antistatic agents, slip agents, antiblocking agents, lubricants, pigments, dyes, plasticizers, antioxidants, hydrochloric acid absorbers, and antioxidants, as necessary, within the scope of the object of the present invention.

[0052] The stretched film of the present invention is a laminated film having an intermediate layer and a skin layer. In the stretched film of the present invention, the intermediate layer and the skin layer are directly laminated to each other. In the stretched film of the present invention, the thickness of the skin layer (when skin layers are present on both sides of the intermediate layer, the sum of the thicknesses of both skin layers) is preferably 5 to 60% of the total thickness of the stretched film.

[0053] When the thickness of the skin layer accounts for 5% or more of the total thickness of the film, the stretching processability is improved and stable stretching at a high stretch ratio is possible. From this viewpoint, the thickness of the skin layer (when skin layers are present on both sides of the intermediate layer, the sum of the thicknesses of both skin layers) is preferably 5% or more, and particularly preferably 10% or more, of the total thickness of the stretched film.

[0054] When the thickness of the skin layer is 60% or less of the total film thickness, the stretched film of the present invention has excellent recyclability. From this viewpoint, the thickness of the skin layer (when skin layers are present on both sides of the intermediate layer, the sum of the thicknesses of both skin layers) is preferably 30% or less, and particularly preferably 10% or less of the total thickness of the stretched film.

[0055] The stretched film of the present invention is obtained by stretching a raw sheet. A known method for forming a film can be used as a method for producing the raw sheet. Specifically, a T-die cast film forming method, an inflation film forming method, etc. can be adopted. The manufacturing conditions of the raw sheet are not particularly limited, but the thickness of the raw sheet is preferably 0.3 mm to 2.5 mm. More preferably, it is 0.5 mm to 2.0 mm.

[0056] The stretching method may be a known method for producing a stretched film. Specifically, roll stretching, tenter stretching, tubular stretching, or a combination of the stretching methods may be used. The stretching (area) ratio is usually 4 to 60 times, preferably 10 to 50 times.

[0057] Although there is no particular limitation on the total thickness of the stretched film of the present invention, from the viewpoint of ensuring practical strength, etc., when stretched, the total thickness after stretching is usually 15 μm or more, preferably 18 μm or more, and more preferably 20 μm or more. On the other hand, from the viewpoint of having sufficient flexibility in relation to the application, etc., the total thickness is usually 500 μm or less, preferably 300 μm or less, and more preferably 100 μm or less.

[0058] <Sealant film layer> The sealant film layer is a film composed of an ethylene-based polymer (E). The sealant film layer usually has a thickness in the range of 10 to 200 μm, preferably 11 to 100 μm, and more preferably 12 to 90 μm.

[0059] In the laminate, the sealant film layer is preferably thicker than the base film (stretched film) composed of the intermediate layer and the skin layer. This makes the laminate closer to a single material, which has the advantage of making recycling easier. The total thickness of the sealant film layer is usually 50% or more of the total thickness of the laminate, preferably 60% or more, and more preferably 70% or more. The sealant film layer may consist of one layer, or may consist of multiple layers.

[0060] <Ethylene-based polymer (E)> Examples of the ethylene polymer (E) include ethylene homopolymers, copolymers of ethylene as a main monomer with at least one α-olefin having 3 or more carbon atoms, preferably 3 to 20 carbon atoms, ethylene-vinyl acetate copolymers, saponification products thereof, and ionomers thereof. Specific examples include copolymers of ethylene as a main monomer with at least one α-olefin having 3 to 20 carbon atoms, such as polyethylene, ethylene-propylene copolymer, ethylene-1-butene copolymer, ethylene-1-pentene copolymer, ethylene-1-hexene copolymer, ethylene-4-methyl-1-pentene copolymer, and ethylene-1-octene copolymer.

[0061] The content of these α-olefins is preferably 0.5 to 15 mol %, more preferably 1.0 to 13 mol %, provided that the total of the ethylene content and the α-olefin content is taken as 100 mol %. The ethylene polymer (E) may be one type of polymer or two or more types of polymers.

[0062] The density of the ethylene polymer (E) (ASTM D 1505) is 870 to 930 kg / m 3 The density is preferably 875 kg / m 3 By setting the density to 930 kg / m or more, the surface properties such as slip resistance and blocking resistance are improved. 3 When the above condition is satisfied, the low-temperature sealability is excellent.

[0063] The melt flow rate (ASTM D1238, 190°C, 2.1 kg load) of the ethylene polymer (E) is preferably 0.1 to 20 g / 10 min, more preferably 0.3 to 15 g / 10 min, and further preferably 0.5 to 9.0 g / 10 min. If the melt flow rate is within this range, molding can be performed at a high molding speed using an existing molding machine, and molding stability is improved, which is preferable.

[0064] The ethylene polymer (E) constituting the sealant film layer can be produced by homopolymerizing ethylene or copolymerizing ethylene and an α-olefin having 3 to 20 carbon atoms in the presence of a conventionally known catalyst, such as a multi-site catalyst such as a Ziegler catalyst or a single-site catalyst such as a metallocene catalyst, by a known polymerization method such as a gas phase method, a solution method, a bulk method, or a slurry method. Specific examples of the α-olefin having 3 to 20 carbon atoms include propylene, 1-butene, 1-hexene, 1-heptene, 1-octene, 1-decene, 1-undecene, 3-methyl-1-butene, 3-methyl-1-pentene, 4-methyl-1-pentene, 4-methyl-1-hexene, and 4,4-dimethyl-1-hexene. These may be used alone or in combination of two or more. In addition, the ethylene and the α-olefin may be derived from biomass or fossil fuel, or both a biomass-derived monomer and a fossil fuel-derived monomer may be used.

[0065] The sealant film layer can be formed by various known methods. As a method for forming a non-stretched film, specifically, a T-die cast film forming method, an inflation film forming method, etc. can be adopted. As a method for forming a stretched film, specifically, roll stretching, tenter stretching, tubular stretching, or a combination of the above stretching methods can be mentioned. The stretching (area) ratio is usually 1.5 to 50 times, preferably 2 to 40 times.

[0066] The sealant film layer may contain, in addition to the ethylene polymer (E), additives such as other resins, tackifiers, weather stabilizers, heat stabilizers, antistatic agents, antislip agents, antiblocking agents, lubricants, pigments, dyes, plasticizers, antioxidants, hydrochloric acid absorbers, and antioxidants.

[0067] [Laminate] The laminate of the present invention is formed by laminating a stretched film as a base film and a sealant film layer. Examples of the laminate include, but are not limited to, a structure such as base film (stretched film) / sealant film layer. For example, when a plurality of base films (stretched films) are used, one type may be used alone or two or more types may be used. In addition, an adhesive layer may be provided between the base film (stretched film) and the sealant film layer.

[0068] The laminate of the present invention has excellent heat seal strength, which can be measured by the following method. That is, the sealant film layers of two identical laminates are placed together, and the lower seal bar is heated to 70°C and the upper seal bar to 120°C, and heated at a pressure of 0.2 MPa for 1 second with a seal bar width of 5 mm, then allowed to cool. Next, 15 mm wide test pieces are cut from each heat-sealed test piece, and the heat-sealed portion of each test piece is peeled off in a direction 180° to the laminate surface at a crosshead speed of 300 mm / min, and the peel strength is expressed as (N / mm).

[0069] The term "excellent heat seal strength" means that the maximum value of the heat seal strength of each test piece in the above-mentioned heat seal strength measurement is preferably 19 N / 15 mm or more. If the maximum heat seal strength of the laminate is 19 N / 15 mm or more, the adhesion of the sealed portion is excellent and it is possible to fill heavy objects.

[0070] Here, in the above-mentioned heat seal strength measurement, delamination occurs between the intermediate layer and the skin layer of the two sealed laminates, and the peel strength decreases. In the present invention, the peel distance at the point where delamination occurs (the point where the peel strength is maximum) is preferably 10 mm or more, and more preferably 20 mm or more. If the peel distance until delamination occurs in the laminate is 10 mm or more, the decrease in peel strength is suppressed, and the filling of heavy loads is also possible.

[0071] The laminate of the present invention may be produced by laminating a base film (stretched film) and a sealant film layer by dry lamination, non-solvent lamination, sand lamination, etc., or may be produced by laminating a base film (stretched film) and a sealant film layer by melt extrusion lamination. Among these, the lamination method by dry lamination or melt extrusion lamination is preferable.

[0072] The laminate of the present invention may further have at least one functional layer selected from a printed layer, a barrier layer, and an embossed layer in order to impart specific functions to the base film (stretched film) and the sealant film layer. From the viewpoint of imparting a functional material to the base film (stretched film) and the sealant film layer, it is preferable that these functional layers are adjacent to at least one film selected from the base film (stretched film) and the sealant film layer or are in contact with the at least one film selected from the base film (stretched film) and the sealant film layer via an adhesive layer.

[0073] That is, the functional material layer is adjacent to or in contact with, via an adhesive layer, at least one layer selected from the intermediate layer, skin layer, and sealant film layer of the stretched film.

[0074] The functional material layer may be a resin film on which an inorganic compound or an inorganic oxide is vapor-deposited, a metal foil, a coating of a resin having a special function, a resin film on which a pattern is printed, or the like. The resin film used here can be a polymer film similar to the polymer used in the stretched film, and similar plastic compounding agents and additives can also be added in any amount depending on the purpose, as long as they do not adversely affect other performances.

[0075] The resin film can be produced, for example, by using one or more resin polymers selected from the group of resin polymers described above as polymers used in stretched films, and by a conventional film-forming method such as extrusion, cast molding, T-die method, cutting method, inflation method, etc., or by a multilayer co-extrusion film-forming method using two or more resins. Furthermore, from the viewpoint of film strength, dimensional stability, and heat resistance, the film can be stretched uniaxially or biaxially using, for example, a tenter method or a tubular method.

[0076] For example, when the laminate includes a barrier layer as a functional material layer, it can be manufactured by a method similar to the manufacturing method of a laminate, which includes a step of forming the barrier layer as one layer in the base film (stretched film) and sealant film layer by metal vapor deposition, a coating method or a co-extrusion method, and a step of laminating the above-mentioned base film (stretched film) and the sealant film layer. As described above, the laminate of the present invention has excellent heat seal strength. Furthermore, the peel distance before delamination occurs is long, making it possible to fill the laminate with heavy loads.

[0077] [Packaging] A package can be obtained from the laminate of the present invention. The package formed from the laminate of the present invention has excellent heat sealability. For example, a package such as a packaging bag can be produced by placing the sealant film layers of the laminate facing each other, or placing the sealant film layer of the laminate facing another film, and then heat-sealing at least a part of the periphery from the outer surface side to form a desired container shape. Also, a sealed package can be produced by heat-sealing the entire periphery. If the molding process of this package is combined with a filling process of the contents, that is, the bottom and sides of the package are heat-sealed, the contents are filled, and then the top is heat-sealed, a package containing the contents can be produced. This package can be used in an automatic packaging device for solids such as snacks and bread, powders, or liquid materials.

[0078] In addition, a container in which the contents are packed can be obtained by filling a container in which a sheet of the laminate has been formed into a cup shape by vacuum forming, compressed air forming, or the like, a container obtained by injection molding, or a container formed from a paper base material, and then covering the container with the laminate of the present invention as a lid and heat sealing the top or side of the container. This container is suitably used for packaging instant noodles, miso, jelly, pudding, snacks, etc.

[0079] When the laminate or packaging has a mono-material structure, it can be effectively used as a recycled product. Molded products that are recycled laminates or packaging can reduce the amount of newly polymerized plastic used, and can contribute to reducing the environmental load. EXAMPLES

[0080] Next, the laminate of the present invention will be described in more detail with reference to examples, but the present invention is not limited to these. The materials used in the examples and comparative examples are shown below.

[0081] <Stretched film> <Middle Class> <Ethylene-based polymer (A)> LLDPE-1: Linear low density polyethylene (MFR (190℃, 2.16kg load, conforming to ASTM D1238): 1.8g / 10min, density: 936kg / m 3 , melting point: 127℃) HDPE: High density polyethylene (MFR (190℃, 2.16kg load, conforming to ASTM D1238): 1.1g / 10min, density: 950kg / m 3 , melting point: 132℃)

[0082] <Propylene-based polymer (B)> Propylene polymer 1: Propylene resin composition 1 was prepared by melt-kneading 90% by mass of propylene-ethylene-1-butene copolymer (hereinafter, referred to as "PEBR-1") and 10% by mass of propylene homopolymer, and then pelletizing the mixture.

[0083] PEBR-1 was prepared in accordance with the method described in the Examples section of the <Third Invention> in WO2006 / 57361, and contains 16 mol % ethylene, 78 mol % propylene, and 6 mol % 1-butene. It had no observed melting point (Tm) measured by a normal method, an MFR (230°C, 2.16 kg load, in accordance with ASTM D1238) of 6 g / 10 min, a glass transition temperature of -21°C, a molecular weight distribution (Mw / Mn) measured by GPC of 2.0, and a Shore A hardness (in accordance with ASTM D-2240) of 73. 13 The isotactic triad fraction (mm) calculated by C-NMR was 92%. The propylene homopolymer has a melting point (Tm) of 160° C., measured by a heating-reheating method, and an MFR (230° C., 2.16 kg load, in accordance with ASTM D1238) of 7 g / 10 min.

[0084] Propylene polymer 2: Propylene resin composition 2 was prepared by melt-kneading 85% by mass of propylene-ethylene-1-butene copolymer (hereinafter, referred to as "PEBR-2") and 15% by mass of propylene homopolymer, and then pelletizing the mixture. PEBR-2 was prepared in accordance with the method described in the Examples section of the <Third Invention> in WO2006 / 57361, had an ethylene content of 14 mol%, a propylene content of 67 mol%, and a 1-butene content of 19 mol%, had no melting point (Tm) measured by a normal method, had an MFR (230°C, 2.16 kg load, in accordance with ASTM D1238) of 6 g / 10 min, a glass transition temperature of -29°C, a molecular weight distribution (Mw / Mn) measured by GPC of 2.1, and a Shore A hardness (in accordance with ASTM D-2240) of 30. 13 The isotactic triad fraction (mm) calculated by C-NMR was 92%. The propylene homopolymer is the same as the propylene resin composition 1.

[0085] PER-1: Propylene-ethylene copolymer (MFR (230°C, 2.16 kg load, compliant with ASTM D1238): 8 g / 10 min, melting point: 75°C, propylene content: 87 mol%, ethylene content: 13 mol%) PER-2: Propylene-ethylene copolymer (MFR (190°C, 2.16 kg load, compliant with ASTM D1238): 1.4 g / 10 min, melting point: 46°C, propylene content: 78 mol%, ethylene content: 22 mol%) PBR-1: Propylene-1-butene copolymer (MFR (230°C, 2.16 kg load, in accordance with ASTM D1238): 7 g / 10 min, melting point: 75°C, propylene content: 75 mol%, 1-butene content: 25 mol%) PBR-2: Propylene-1-butene copolymer (MFR (230°C, 2.16 kg load, in accordance with ASTM D1238): 7 g / 10 min, MFR (190°C, 2.16 kg load, in accordance with ASTM D1238): 3 g / 10 min, melting point: 98°C, propylene content: 85 mol%, 1-butene content: 15 mol%)

[0086] <Skin layer> <Propylene-based polymer (C)> rPP: Random polypropylene (MFR (230°C, 2.16 kg load, compliant with ASTM D1238): 7 g / 10 min, melting point: 140°C, propylene content: 95 mol%, ethylene content: 1 mol%, 1-butene content: 4 mol%)

[0087] <Ethylene-based polymer (D)> EBR-1: Ethylene-1-butene copolymer (MFR (190°C, 2.16 kg load) = 3.6 g / 10 min, density 885 kg / m3, melting point: 66°C, ethylene content: 89 mol%, 1-butene content: 11 mol%)

[0088] <Sealant film> <Ethylene-based polymer (E)> LLDPE-2: Linear low density polyethylene (MFR (190℃, 2.16kg load, conforming to ASTM D1238): 1.0g / 10min, density: 918kg / m 3 , melting point: 121℃) LLDPE-3: Linear low density polyethylene (MFR (190℃, 2.16kg load, conforming to ASTM D1238): 1.0g / 10min, density: 916kg / m 3 , melting point: 122℃) EBR-2: Ethylene-1-butene copolymer (MFR (190℃, 2.16kg load) = 1.2g / 10 minutes, density: 885kg / m 3 Melting point: 66°C, ethylene content: 89 mol%, 1-butene content: 11 mol%)

[0089] The melting point, stretchability, tensile properties, haze (transparency), interlayer peel strength between the intermediate layer and the skin layer, heat seal strength, and peel distance until interlayer delamination occurs of each (co)polymer were measured by the following measurement methods.

[0090] <Melt point measurement method> (Ethylene-based polymer (A), propylene-based polymer (C), ethylene-based polymer (D), and ethylene-based polymer (E)) Using a differential scanning calorimeter (PerkinElmer DSCPyris1) in a nitrogen atmosphere (20 mL / min), approximately 5 mg of sample was heated to 200°C and held for 10 minutes, then cooled to 30°C at 10°C / min and held for 5 minutes, and then heated to 200°C at 10°C / min. The temperature at the apex of the crystal melting peak was taken as the melting point (Tm).

[0091] (Propylene polymer) Using a differential scanning calorimeter (DSC manufactured by Seiko Instruments Inc.), approximately 10 mg of the sample was packed into a measurement aluminum pan under a nitrogen atmosphere (20 mL / min), the temperature was raised to 200°C at 100°C / min and held for 5 minutes, then cooled to -100°C at 10°C / min, and then raised to 200°C at 10°C / min. The temperature at the apex of the crystal melting peak was taken as the melting point (Tm).

[0092] <Method of measuring stretchability> A stretched raw film was prepared in which an intermediate layer and a skin layer were laminated to the layer structure shown in Table 1. Using a batch-type biaxial stretching machine, stretching was performed at 4x4 or 4x8 times lengthwise and widthwise at the temperatures shown in Table 1 (124°C to 132°C, 4°C intervals), and the stretching ratio at which the film could be stretched without breaking was evaluated.

[0093] <Tensile properties> A test piece having a width of 15 mm and a length of 150 mm was cut out from the stretched film (thickness 25 μm) produced in the examples and the like. Next, the tensile modulus (YM) (unit: MPa) of the test piece was measured in accordance with JIS K7127 using a universal material testing machine "AG-X-5" manufactured by Shimadzu Corporation under the conditions of a chuck distance of 50 mm, a tensile speed of 300 mm / min, and a temperature of 23° C. Measurements were performed in the MD direction and the TD direction.

[0094] <Haze (Transparency)> Using a haze meter "HM-150" manufactured by Murakami Color Research Laboratory Co., Ltd., measurements were carried out in accordance with JIS K7136 for the stretched films (thickness 25 μm) produced in the examples, and the haze was calculated according to the following formula. Haze (%) = 100 x (diffuse transmitted light amount) / (total transmitted light amount)

[0095] <Total light transmittance (%)> The total light transmittance (%) of the stretched films (thickness 25 μm) produced in the examples was measured using a haze meter "HM-150" manufactured by Murakami Color Research Laboratory Co., Ltd.

[0096] <Interlayer peel strength between middle layer and skin layer of oriented film> Two sheets of the stretched films produced in the Examples and the like were overlapped and both sides of the overlapped films were sandwiched between Teflon (registered trademark) sheets having a thickness of 50 μm to prepare a test specimen.

[0097] Next, the heat seal bar of a heat seal tester (TP-701-G model, manufactured by Tester Sangyo Co., Ltd.) was set to 5 mm wide x 300 mm long, and the lower heat seal bar was set to 70° C. The upper heat seal bar was set to 150° C., and the test specimen (Teflon sheet / stretched film / stretched film / Teflon sheet) was sandwiched between the seal bars and heat sealed at a pressure of 0.2 MPa for 1.0 second.

[0098] Then, a 15 mm wide slit was made in the test specimen to include the heat-sealed portion, and the unsealed portion was pulled by hand to partially peel off the interface, and the interlayer adhesive strength (interlayer strength) was measured at a speed of 300 mm / min using a tensile tester (Shimadzu Corporation, EZ-X). The above procedure was repeated five times, and the average value was taken as the heat-seal strength.

[0099] That is, this determines the adhesive strength (interlayer strength) between the skin layer and the intermediate layer of the stretched film, that is, the heat seal strength.

[0100] <Method of measuring heat seal strength of laminate and peel distance until delamination occurs> The sealant film layers of two laminates prepared in the examples were placed together, and both sides of the laminated films were sandwiched between 50 μm-thick Teflon (registered trademark) sheets to prepare a test specimen. Next, the heat seal bar of a heat seal tester (TP-701-G, manufactured by Tester Sangyo Co., Ltd.) was set to 5 mm wide x 300 mm long, and the lower heat seal bar was set to 70°C.

[0101] The upper heat seal bar was set to 120°C, the test piece (Teflon sheet / laminate / laminate / Teflon sheet) was sandwiched between the seal bars, and heat sealed for 1.0 second at a pressure of 0.2 MPa. The Teflon sheet was removed, and the heat-sealed film portion was left at about 23°C for 1 day.

[0102] Then, a 15 mm wide slit was made in the film to include the heat-sealed portion, and the unsealed portion was fixed to a tensile tester (Shimadzu Corporation, EZ-X) and the peel strength of the film was measured at a speed of 300 mm / min. The above operation was repeated five times, and the average value was taken as the heat-seal strength (unit: N / 15 mm).

[0103] In the above heat seal strength measurement, in all of the Examples and Comparative Examples, delamination occurred between the intermediate layer and the skin layer of the stretched film during peeling, and the peel strength decreased. The peel distance at the point where delamination occurred (the point of maximum peel strength) was recorded as the peel distance (unit: mm) until delamination occurred.

[0104] [Example 1] (Preparation of sealant film) The resin composition for the sealant film layer shown below was fed into an extruder, and an inflation molding die (die diameter 200 mmφ, lip gap 2.0 mm) was used. The resin temperature was set to 200°C, and the extrusion amount of the extruder was set so that the thickness of the sealant film layer would be 50 μm, to produce a sealant film.

[0105] Resin composition for sealant film layer A resin composition obtained by blending LLDPE-3 and EBR-2 in a weight ratio of 70 / 30.

[0106] (Preparation of stretched raw film) The resin composition for the intermediate layer and rPP for the skin layer shown below were fed into their respective extruders, and a three-layer co-extruded film with a layer thickness of 800 μm was molded using the T-die method so that the thickness ratio of skin layer / intermediate layer / skin layer was 8.0:84.0:8.0, to produce a stretched raw film.

[0107] The stretching processability of the obtained raw stretched film was evaluated according to the above-mentioned method. The results are shown in Table 1. Next, the raw stretched film was stretched 4×8 times at 128° C. to obtain a stretched film, and the haze, total light transmittance, elastic modulus, and interlayer strength between the intermediate layer and the skin layer were measured according to the above-mentioned methods. The results are shown in Table 2.

[0108] Resin composition for intermediate layer A resin composition obtained by blending LLDPE-1 and propylene resin composition 1 in a weight ratio of 90 / 10.

[0109] (Preparation of Laminate) A stretched film was obtained by stretching the stretched raw film 4x8 times at 128℃ on one side of the sealant film, and the stretched film was laminated via an adhesive layer by dry lamination to produce a laminated film. Using this laminated film, the heat seal strength and the peel distance until delamination occurred were measured according to the above-mentioned method. The results are shown in Table 3.

[0110] [Examples 2 to 13, Comparative Example 1] A stretched raw film (unstretched film) was produced in the same manner as in Example 1, except that the composition of the resin composition for the intermediate layer and the composition of the resin composition for the skin layer were changed to the compositions shown in Table 1. The stretching processability of the obtained raw stretched film was evaluated according to the above-mentioned method. The results are shown in Table 1.

[0111] Next, the raw stretched film was stretched 4×8 times at 128° C. to obtain a stretched film, and the haze, total light transmittance, elastic modulus, and interlaminar strength were measured according to the above-mentioned methods. The results are shown in Table 2.

[0112] A stretched film was obtained by stretching the stretched raw film 4x8 times at 128℃ on one side of the sealant film, and the stretched film was laminated via an adhesive layer by dry lamination to produce a laminated film. Using this laminated film, the heat seal strength and the peel distance until delamination occurred were measured according to the above-mentioned method. The results are shown in Table 2.

[0113] [Examples 14 to 16, Comparative Examples 2 to 7] A stretched raw film was prepared in the same manner as in Example 1, except that the composition of the resin composition for the intermediate layer and the composition of the resin composition for the skin layer were changed to the compositions shown in Table 1, and the thickness of the stretched raw film was changed to the thickness shown in Table 1. The stretching processability of the obtained raw stretched film was evaluated according to the above-mentioned method. The results are shown in Table 1.

[0114] [Table 1-1]

[0115] [Table 1-2]

[0116] [Table 2]

[0117] [Table 3] [Industrial Applicability]

[0118] The stretched film and laminate of the present invention have preferable properties as a film, such as recyclability, mechanical strength, transparency, etc., and also have improved stretch processability and interlayer adhesion, and can be used for a variety of applications.

Claims

1. A stretched film having an intermediate layer and a skin layer formed on one or both sides of the intermediate layer, the stretched film satisfying the following requirements (1) and (2): Requirement (1): the intermediate layer contains an ethylene-based polymer (A) and a propylene-based polymer (B); Requirement (2): The skin layer contains a propylene-based polymer (C).

2. The propylene-based polymer (B) of the intermediate layer is Requirement (b1) The melting point measured by DSC is less than 120° C. or no melting point is observed. Requirement (b2) 51 to 90 mol % of structural units derived from propylene; 7 to 24 mol % of constitutional units derived from ethylene, and Contains 3 to 25 mol % of structural units derived from α-olefins having 4 to 20 carbon atoms Propylene-ethylene-α-olefin copolymer that satisfies the above requirements. (wherein the total of the structural units derived from propylene, the structural units derived from ethylene, and the structural units derived from an α-olefin having 4 to 20 carbon atoms is 100 mol %).

3. The stretched film according to claim 1, wherein the propylene-based polymer (B) of the intermediate layer contains one or more propylene-α-olefin copolymers selected from the group consisting of propylene-ethylene copolymers and propylene-1-butene copolymers.

4. 2. The stretched film according to claim 1, wherein the skin layer contains 3 to 40% by mass of an ethylene-based polymer (D) (wherein the total of the propylene-based polymer (C) and the ethylene-based polymer (D) is 100% by mass).

5. 2. The stretched film of claim 1, which is stretched from 2 to 8 times in the machine direction and from 2 to 16 times in the transverse direction.

6. A laminate comprising the stretched film according to claim 1 and a sealant film layer.

7. 8. The laminate according to claim 7, wherein the sealant film layer comprises an ethylene-based polymer (E).

8. The laminate according to claim 7, further comprising at least one functional layer selected from a printing layer, a barrier layer and an embossed layer, the functional material layer being adjacent to or in contact with at least one layer selected from the intermediate layer, the skin layer and the sealant film layer via an adhesive layer.

9. A package comprising the laminate according to claim 6.