Heat-sealable polyethylene laminate

Abstract

Provided is a polyethylene laminate that is highly recyclable, has excellent physical properties such as rigidity, strength and impact resistance, and is excellent in heat sealability.　This heat-sealing polyethylene laminate comprises: a stretched film of an ultra-high-molecular-weight polyethylene resin (A) having a viscosity-average molecular weight of 300,000 to 15 million; and a low-molecular-weight ethylene resin layer disposed on at least one side of the stretched film of the ultra-high-molecular-weight polyethylene resin (A) and constituted by an ethylene resin.

Description

[Technical Field]

[0001] The present invention relates to a heat-sealable polyethylene laminate. [Background technology]

[0002] Polyethylene film is used as a packaging material because it has moderate flexibility, excellent transparency, moisture resistance, chemical resistance, etc., and is inexpensive. Polyethylene film, which has a melting point of 100°C to 140°C, is also useful as a packaging material with heat sealability.

[0003] However, polyethylene film has low rigidity, impact resistance, heat resistance, etc., and from the viewpoint of durability, there are applications in which it cannot be used alone. To solve these problems, packaging materials obtained by laminating polyethylene film with other resin films (e.g., polyester film, polyamide film) are widely used (e.g., Patent Document 1).

[0004] Meanwhile, in recent years, social issues such as waste plastics have been attracting attention, and with the growing demand for building a recycling-oriented society, there is a demand for improving the recyclability of packaging materials. Packaging materials made from a combination of films of different materials, such as those described above, have the problem of being difficult to recycle through material recycling, chemical recycling, and other methods. In response to this, packaging materials made from the same type of resin material have been proposed, formed by laminating an oriented polyethylene film and an unoriented polyethylene film (e.g., Patent Documents 2 and 3). The oriented polyethylene film is used to compensate for the mechanical properties of the unoriented polyethylene film. However, even this oriented polyethylene film does not have the same mechanical properties as biaxially oriented polyamide film or biaxially oriented polyester film, and the packaging material may have insufficient heat seal strength. Furthermore, the films are laminated via an adhesive, which also presents the problem of low recyclability.

[0005] Furthermore, ultra-high molecular weight polyethylene films have been proposed as polyethylene films with excellent rigidity, heat resistance, and strength (for example, Patent Document 4). However, the strength of typical ultra-high molecular weight polyethylene films is lower than that of biaxially oriented polyamide films and biaxially oriented polyester films, resulting in low heat seal strength and making them unsuitable as packaging materials for particularly heavy goods. [Prior art documents] [Patent documents]

[0006] [Patent Document 1] Japanese Patent Application Laid-Open No. 2005-104525 [Patent Document 2] Japanese Patent Application Publication No. 2019-171860 [Patent Document 3] Japanese Patent Application Publication No. 2019-529165 [Patent Document 4] Japanese Patent Application Laid-Open No. 1994-262679 Summary of the Invention [Problem to be solved by the invention]

[0007] The present invention has been made to solve the above-mentioned problems, and an object of the present invention is to provide a polyethylene laminate which has high recyclability, excellent physical properties such as rigidity, strength and impact resistance, and excellent heat-sealability. [Means for solving the problem]

[0008] The heat-sealable polyethylene laminate of the present invention comprises a stretched film of ultra-high molecular weight polyethylene resin (A) having a viscosity average molecular weight of 300,000 to 15,000,000, and a low-molecular weight ethylene resin layer composed of an ethylene resin, which is disposed on at least one side of the stretched film of ultra-high molecular weight polyethylene resin (A). In one embodiment, an anchor coat layer is further provided between the stretched film of the ultra-high molecular weight polyethylene resin (A) and the low molecular weight ethylene resin. In one embodiment, the anchor coat layer has a thickness of 0.01 μm to 0.7 μm. In one embodiment, the stretched film of the ultra-high molecular weight polyethylene resin satisfies all of the following properties (i) to (iv). (i) The tensile strength at 23°C is 100 MPa or more, (ii) a tensile modulus at 23°C of 1500 MPa or more; (iii) 30μm equivalent moisture permeability is 15g / m 2 ·d or less, and (iv) In DSC measurement, it has an endothermic peak below 140°C and an endothermic peak at 140°C or higher, and the endothermic peak at 140°C or higher decreases or disappears during the second heating. In one embodiment, the stretched film of the ultra-high molecular weight polyethylene resin (A) contains the high molecular weight polyethylene resin (A) and a condensed hydroxy fatty acid and / or an alcohol ester thereof (C). In one embodiment, the content of the condensed hydroxy fatty acid and / or its alcohol ester (C) is 0.1 to 10 parts by weight relative to 100 parts by weight of the resin in the stretched film of the ultra-high molecular weight polyethylene resin. In one embodiment, the stretched film of the ultra-high molecular weight polyethylene resin (A) contains the high molecular weight polyethylene resin (A) and a thermoplastic resin (B). In one embodiment, the ethylene-based resin constituting the low-molecular-weight ethylene-based resin layer includes at least one selected from high-pressure low-density polyethylene, ethylene-α-olefin copolymer, ethylene-vinyl acetate copolymer, and ethylene-acrylic acid ester copolymer. In one embodiment, the density of the ethylene-based resin constituting the low-molecular-weight ethylene-based resin layer is 860 kg / m 3 ~955kg / m 3 is. In one embodiment, the low-molecular-weight ethylene-based resin layer contains a tackifier, and the content of the tackifier is 1 part by weight to 30 parts by weight relative to 100 parts by weight of the ethylene-based resin constituting the low-molecular-weight ethylene-based resin layer. In one embodiment, the tackifier is at least one selected from the group consisting of petroleum resins, terpene resins, and rosin-based resins. According to another aspect of the present invention, there is provided recycled polyethylene pellets, which are composed of the above-mentioned heat-sealable polyethylene laminate. [Effects of the Invention]

[0009] According to the present invention, it is possible to provide a polyethylene laminate which is highly recyclable because it can be composed only of a polyethylene resin, and which has excellent physical properties such as rigidity, strength, and impact resistance, as well as excellent heat-sealability. The polyethylene film of the present invention is advantageous in terms of recyclability in that it can be molded by extrusion lamination, i.e., can be molded without using an adhesive or the like. [Brief explanation of the drawings]

[0010] [Figure 1] 1 is a schematic cross-sectional view of a polyethylene laminate according to one embodiment of the present invention. [Figure 2] 1 is a schematic cross-sectional view of a polyethylene laminate according to another embodiment of the present invention. [Figure 3] 1 is a schematic cross-sectional view of a polyethylene laminate according to another embodiment of the present invention. DETAILED DESCRIPTION OF THE INVENTION

[0011] A. Heat-sealable polyethylene laminate FIG. 1 is a schematic cross-sectional view of a heat-sealable polyethylene laminate according to one embodiment of the present invention. The heat-sealable polyethylene laminate 100 comprises a stretched film 10 of ultra-high molecular weight polyethylene resin and a layer 20 of low-molecular weight ethylene resin disposed on at least one side of the stretched film 10 of ultra-high molecular weight polyethylene resin. The viscosity-average molecular weight of the ultra-high molecular weight polyethylene resin (A) constituting the stretched film 10 is 300,000 to 15,000,000. In one embodiment, the polyethylene laminate may comprise any appropriate other layer. In one embodiment, when the heat-sealable polyethylene laminate comprises a layer made of a material other than a polyethylene resin, the content of the material other than a polyethylene resin in the polyethylene laminate is 10% by weight or less. Preferably, the heat-sealable polyethylene laminate comprises only a layer made of an ethylene resin. In one embodiment, the stretched film 10 of ultra-high molecular weight polyethylene resin and the layer 20 of low-molecular weight ethylene resin are laminated directly (i.e., without any other layer interposed therebetween).

[0012] 2 is a schematic cross-sectional view of a heat-sealable polyethylene laminate according to another embodiment of the present invention. The heat-sealable polyethylene laminate 200 further comprises an anchor coat layer 30 between the stretched ultra-high molecular weight polyethylene resin film 10 and the low-molecular weight ethylene resin layer 20.

[0013] Figure 3 is a schematic cross-sectional view of a heat-sealable polyethylene laminate according to another embodiment of the present invention. The low-molecular-weight ethylene-based resin layer 20 may be a single layer as shown in Figures 1 and 2, or may be a multi-layer (two layers in the illustrated example) as shown in Figure 3. The heat-sealable polyethylene laminate 300 in Figure 3 comprises, as the low-molecular-weight ethylene-based resin layer 20, a low-molecular-weight ethylene-based resin layer (I) 21 and a low-molecular-weight polyethylene-based resin layer (II) 22.

[0014] The heat-sealable polyethylene laminate has heat-sealability. In the present invention, heat-sealability means a property in which, when films (heat-sealable polyethylene laminates) are laminated together and heated, the contact surfaces of the films melt and bond together. In one embodiment, the heat-sealable polyethylene laminate exhibits heat-sealability at a temperature of 170°C or lower (preferably 150°C or lower, more preferably 100°C to 130°C). In the heat-sealable polyethylene laminate, the low-molecular-weight ethylene-based resin layers are brought into contact with each other, thereby exhibiting heat-sealability. Hereinafter, the "heat-sealable polyethylene laminate" may also be simply referred to as the "polyethylene laminate."

[0015] As described above, the viscosity-average molecular weight of an ultra-high molecular weight polyethylene resin is 300,000 to 15,000,000. An "ultra-high molecular weight polyethylene resin" and a "low-molecular weight ethylene resin" are distinguished by their viscosity-average molecular weights. In other words, in this specification, a "low-molecular weight ethylene resin" refers to an ethylene resin having a viscosity-average molecular weight smaller than that of an "ultra-high molecular weight polyethylene resin," and in one embodiment, refers to an ethylene resin having a viscosity-average molecular weight of less than 300,000. In this specification, a polyethylene resin (such as an ultra-high molecular weight polyethylene resin or a low-molecular weight ethylene resin) refers to a resin containing 50 mol % or more of ethylene-derived structural units.

[0016] In one embodiment, the above-mentioned stretched ultra-high molecular weight polyethylene resin film (hereinafter also referred to as ultra-high molecular weight stretched film A) satisfies all of the following properties (i) to (iv). (i) The tensile strength at 23°C is 100 MPa or more, (ii) a tensile modulus at 23°C of 1500 MPa or more; (iii) 30μm equivalent moisture permeability is 15g / m 2 ·d or less, and (iv) In DSC measurement, it has an endothermic peak below 140°C and an endothermic peak at 140°C or higher, and the endothermic peak at 140°C or higher decreases or disappears during the second heating. Thus, the ultra-high molecular weight stretched film A used in the present invention is particularly useful in that it can achieve a good balance between mechanical properties and low moisture permeability.

[0017] The polyethylene laminate of the present invention has excellent heel sheet properties due to the inclusion of a low-molecular-weight ethylene-based resin layer. Furthermore, the polyethylene laminate has excellent physical properties such as rigidity, strength, and impact resistance due to the inclusion of the ultra-high molecular weight stretched film A, which has excellent mechanical properties, as described above. Furthermore, the polyethylene laminate can be composed of the same type of resin, which makes it highly recyclable.

[0018] The thickness of the polyethylene laminate is preferably 20 μm to 300 μm, and more preferably 30 μm to 200 μm.

[0019] A-1. Ultra-high molecular weight polyethylene resin oriented film (Ultra-high molecular weight oriented film A) The thickness of the ultra-high molecular weight stretched film A is preferably 15 μm to 300 μm, more preferably 20 μm to 200 μm, and even more preferably 30 μm to 100 μm. If the thickness is within this range, the film can have the desired rigidity.

[0020] The degree of crystal orientation of the above-mentioned ultrahigh molecular weight stretched film A is preferably 0.94 to 1, more preferably 0.95 to 1, and even more preferably 0.96 or more and less than 1. Within such a range, an ultrahigh molecular weight stretched film A with low moisture permeability can be obtained, and an ultrahigh molecular weight stretched film A with excellent rigidity and strength can be obtained. The degree of crystal orientation can be determined by determining an azimuth angle distribution curve derived from the (110) plane at 2θ from a wide-angle X-ray diffraction image obtained by wide-angle X-ray diffraction measurement, measuring the half-widths of the peaks at 0° and 180°, and calculating the degree of crystal orientation using the following formula: Crystal orientation degree = (360 - half-width x 2) / 360

[0021] The tensile strength of the ultrahigh molecular weight stretched film A at 23°C is preferably 100 MPa to 700 MPa, more preferably 120 MPa to 500 MPa, even more preferably 150 MPa to 400 MPa, and particularly preferably 200 MPa to 350 MPa. Within these ranges, an ultrahigh molecular weight stretched film A with excellent mechanical strength can be obtained. The tensile strength can be measured in accordance with JIS K 7161. In one embodiment, the tensile strength refers to the tensile strength in the machine direction (MD) when producing the ultrahigh molecular weight stretched film A (during melt sheet calendering).

[0022] The tensile modulus of the ultra-high molecular weight stretched film A at 23°C is preferably 3,000 MPa to 20,000 MPa, more preferably 3,200 MPa to 15,000 MPa, and even more preferably 4,000 MPa to 12,000 MPa. Within these ranges, a polyethylene laminate can be obtained in which shrinkage and curling in the width direction are suppressed. The modulus can be measured in accordance with JIS K 7161. In one embodiment, the tensile strength refers to the tensile strength in the machine direction (MD) when producing the ultra-high molecular weight stretched film A (during melt sheet calendering).

[0023] The moisture permeability of the polyethylene laminate in terms of 30 μm is preferably 10 g / m 2 ·d or less, and more preferably 9.5 g / m 2 Within this range, when the polyethylene laminate is used as a packaging material, spoilage of the contents can be significantly prevented. The lower the 30 μm equivalent moisture permeability of the polyethylene laminate, the better, but the lower limit is, for example, 1 g / m 2 d, more preferably 0.5 g / m 2The moisture permeability is determined in accordance with the moisture permeability test (moisture sensor method) of JIS K7129, by measuring the amount of water vapor (g) that passes through an 80 mm diameter sample in 24 hours at a temperature of 40°C and a humidity of 90% RH. The 30 μm equivalent moisture permeability is calculated by multiplying the moisture permeability measured as above by (30 μm / thickness of polyethylene laminate (μm)).

[0024] As described above, the ultrahigh molecular weight stretched film A may have an endothermic peak L below 140°C and an endothermic peak H at 140°C or higher during the first heating in DSC measurement. Endothermic peak L is preferably between 110°C and 139°C, more preferably between 125°C and 139°C. Endothermic peak H is preferably between 142°C and 160°C, more preferably between 144°C and 155°C. The ultrahigh molecular weight stretched film A of the present invention may have multiple endothermic peaks as described above, thereby enabling the production of an ultrahigh molecular weight stretched film A with excellent mechanical strength and heat resistance. Furthermore, the ultrahigh molecular weight stretched film A is characterized in that, during the second heating in DSC measurement, endothermic peak H at 140°C or higher may decrease or disappear. As described above, the presence of endothermic peak H that disappears (or decreases) during the second heating means that the ultrahigh molecular weight stretched film A of the present invention preferably contains a highly oriented polymer. The endothermic peak can be measured using DSC by increasing the temperature from a starting temperature of 30°C to 230°C at a heating rate of 10°C / min and a cooling rate of 10°C / min, holding at 230°C for 3 minutes, then decreasing the temperature to 30°C, and then further increasing the temperature to 230°C.

[0025] In one embodiment, the ultra-high molecular weight stretched film A can be obtained by molding a resin composition containing an ultra-high molecular weight polyethylene resin (A) by melt sheet rolling. In one embodiment, the ultra-high molecular weight stretched film A (i.e., the resin composition) contains a thermoplastic resin (B). In another embodiment, the ultra-high molecular weight stretched film A (i.e., the resin composition) contains a condensed hydroxy fatty acid and / or its alcohol ester (C) (hereinafter simply referred to as compound (C)). By adding the thermoplastic resin (B) and / or compound (C), a resin composition that exhibits excellent moldability by melt sheet rolling can be obtained. Note that melt sheet rolling refers to a molding method in which a resin composition is rolled between two or more rolls to form a film having a predetermined thickness (details will be described later).

[0026] (Ultra-high molecular weight polyethylene resin (A)) As described above, the viscosity-average molecular weight of the ultra-high molecular weight polyethylene resin (A) is 300,000 to 15,000,000. By using an ultra-high molecular weight polyethylene resin (A) having such a viscosity-average molecular weight, an ultra-high molecular weight stretched film (A) having excellent abrasion resistance, self-lubrication, impact resistance, low-temperature properties, and chemical resistance can be obtained. The viscosity-average molecular weight of the ultra-high molecular weight polyethylene resin (A) is preferably 500,000 to 8,000,000, and more preferably 1,000,000 to 6,000,000. Within these ranges, an ultra-high molecular weight stretched film (A) having excellent rigidity and strength can be obtained. The ultra-high molecular weight stretched film (A) may contain two or more ultra-high molecular weight polyethylene resins (A) having different molecular weights. The viscosity-average molecular weight (Mv) can be measured by the viscosity method specified in ASTM D4020. Specifically, the intrinsic viscosity (η (dl / g)) is measured according to the viscosity method of ASTM D4020, and the viscosity-average molecular weight (Mv) can be calculated from the following formula (1): Mv=5.37×10 4 η 1.37 ···(1) The intrinsic viscosity of the ultra-high molecular weight polyethylene resin (A) is, for example, 3.5 dL / g or more, and the upper limit of the intrinsic viscosity of the ultra-high molecular weight polyethylene resin is, for example, 60 dL / g or less.

[0027] The ultra-high molecular weight polyethylene resin (A) may be a homopolymer of ethylene or a copolymer of ethylene and another monomer copolymerizable with ethylene. The content of ethylene-derived structural units in the ultra-high molecular weight polyethylene resin (A) is preferably 80 mol % or more, more preferably 90 mol % or more, and even more preferably 95 mol % or more.

[0028] Examples of other monomers copolymerizable with ethylene include α-olefins having 3 or more carbon atoms (preferably 3 to 20 carbon atoms). Examples of α-olefins having 3 or more carbon atoms include propylene, 1-butene, isobutene, 1-pentene, 2-methyl-1-butene, 3-methyl-1-butene, 1-hexene, 3-methyl-1-pentene, 4-methyl-1-pentene, 1-heptene, 1-octene, 1-decene, 1-dodecene, 1-tetradecene, 1-hexadecene, 1-octadecene, and 1-icosene.

[0029] The ultra-high molecular weight polyethylene resin (A) can be produced by any suitable method, for example, by the method described in JP-A-58-83006, in which the above-mentioned monomers are polymerized in the presence of any suitable catalyst.

[0030] The content of the ultra-high molecular weight polyethylene resin (A) is preferably 10 to 90 parts by weight, more preferably 20 to 80 parts by weight, and particularly preferably 30 to 70 parts by weight, per 100 parts by weight of the resin in the ultra-high molecular weight stretched film A.

[0031] (Thermoplastic resin (B)) The viscosity average molecular weight of the thermoplastic resin (B) is not particularly limited as long as it is smaller than the viscosity average molecular weight of the ultra-high molecular weight polyethylene resin (A). The viscosity average molecular weight of the thermoplastic resin (B) is, for example, 1,000,000 or less, and preferably less than 300,000. Within this range, adding the thermoplastic resin (B) to the resin composition for forming the ultra-high molecular weight stretched film A can improve the fluidity of the resin composition. In one embodiment, the viscosity average molecular weight of the thermoplastic resin (B) is 200,000 or less. Within this range, a resin composition with particularly excellent moldability can be obtained.

[0032] The melt flow rate of the thermoplastic resin (B) at 190°C and 2.16 kgf is preferably 0.01 g / 10 min to 150 g / 10 min, more preferably 0.1 g / 10 min to 100 g / 10 min, even more preferably 10 g / 10 min to 90 g / 10 min, and particularly preferably 20 g / 10 min to 80 g / 10 min. Within these ranges, an ultra-high molecular weight stretched film A can be obtained that is particularly excellent in formability and that fully exhibits the properties derived from the ultra-high molecular weight polyethylene resin (A).

[0033] Examples of the thermoplastic resin (B) include olefin-based resins (such as homopolymers of α-olefins and copolymers composed of two or more kinds of α-olefins).

[0034] The α-olefin constituting the thermoplastic resin (B) is preferably an α-olefin having 2 to 10 carbon atoms, more preferably an α-olefin having 2 to 8 carbon atoms, and further preferably ethylene, propylene or 1-butene.

[0035] In one embodiment, a polyethylene resin other than the ultra-high molecular weight polyethylene resin (A) is used as the thermoplastic resin (B). The content of ethylene-derived structural units in the polyethylene resin is preferably 80 mol% or more, more preferably 90 mol% or more, and even more preferably 95 mol% or more. Examples of structural units other than ethylene-derived structural units include structural units derived from monomers copolymerizable with ethylene, such as structural units derived from propylene, 1-butene, isobutene, 1-pentene, 2-methyl-1-butene, 3-methyl-1-butene, 1-hexene, 3-methyl-1-pentene, 4-methyl-1-pentene, 1-heptene, 1-octene, 1-decene, 1-dodecene, 1-tetradecene, 1-hexadecene, 1-octadecene, and 1-icosene.

[0036] The melt flow rate of the polyethylene resin at 190°C and 2.16 kgf is preferably 0.01 g / 10 min to 150 g / 10 min, more preferably 0.1 g / 10 min to 100 g / 10 min, even more preferably 10 g / 10 min to 90 g / 10 min, and particularly preferably 20 g / 10 min to 80 g / 10 min. Within these ranges, an ultra-high molecular weight stretched film A can be obtained that is particularly excellent in formability and that fully exhibits the properties derived from the ultra-high molecular weight polyethylene resin (A).

[0037] In another embodiment, a propylene-based resin is used as the thermoplastic resin (B). Propylene-based resins are advantageous in that they have excellent compatibility with the ultra-high molecular weight polyethylene-based resin (A). The propylene-based resin may be a propylene homopolymer or a copolymer of propylene and a monomer copolymerizable with propylene. Examples of copolymers include random polypropylenes composed of propylene-derived structural units and ethylene-derived structural units, block polypropylenes composed of propylene-derived structural units and ethylene-derived structural units, polypropylene terpolymers composed of propylene-derived structural units, ethylene-derived structural units, and 1-butene-derived structural units, syndiotactic polypropylene, atactic polypropylene, and long-chain branched polypropylene. These resins may be used alone or in combination of two or more. The content of propylene-derived structural units in the propylene-based resin is preferably 50 mol% or more, more preferably 80 mol% or more, more preferably 90 mol% or more, and even more preferably 95 mol% or more.

[0038] The melt flow rate of the propylene resin at 230°C and 2.16 kgf is preferably 0.1 g / 10 min to 1000 g / 10 min, more preferably 0.5 g / 10 min to 800 g / 10 min, and even more preferably 1 g / 10 min to 500 g / 10 min. Within such ranges, an ultra-high molecular weight stretched film A can be obtained that is particularly excellent in moldability and that fully exhibits the properties derived from the ultra-high molecular weight polyethylene resin (A).

[0039] The content of the thermoplastic resin (B) is preferably 20 to 95 parts by weight, more preferably 30 to 85 parts by weight, and even more preferably 40 to 80 parts by weight, relative to 100 parts by weight of the resin in the ultra-high molecular weight stretched film A. Within such a range, a resin composition with excellent moldability can be prepared, and an ultra-high molecular weight stretched film A can be obtained in which the properties derived from the ultra-high molecular weight polyethylene resin (A) are fully exhibited.

[0040] (Condensed hydroxy fatty acid and / or its alcohol ester (C)) By including the condensed hydroxy fatty acid and / or its alcohol ester (C), the fluidity of the resin composition can be increased, and as a result, an ultra-high molecular weight stretched film A with excellent formability can be obtained by melt sheet rolling.

[0041] The condensed hydroxy fatty acid can be obtained by dehydration condensation of a hydroxy fatty acid, for example, by adding an alkali catalyst such as caustic soda to the hydroxy fatty acid and removing reaction water under heating to cause dehydration condensation.

[0042] The condensed hydroxy fatty acid is a condensation product of a hydroxy fatty acid, and the degree of condensation is preferably at least 2, more preferably at least 4. The upper limit of the degree of condensation of the condensed hydroxy fatty acid is, for example, 20. The degree of condensation can be calculated from the acid value of the starting hydroxy fatty acid and the acid value after the condensation reaction.

[0043] The hydroxy fatty acid is a fatty acid having one or more hydroxyl groups in the molecule. Specific examples of the hydroxy fatty acid include ricinoleic acid, 12-hydroxystearic acid, savinic acid, 2-hydroxytetradecanoic acid, iprolic acid, 2-hydroxyhexadecanoic acid, yarapinoleic acid, uniperilic acid, ambrettolic acid, aluritic acid, 2-hydroxyoctadecanoic acid, 18-hydroxyoctadecanoic acid, 9,10-dihydroxyoctadecanoic acid, camrolenoic acid, ferronic acid, and cerebronic acid. The hydroxy fatty acid may be used alone or in combination of two or more.

[0044] The alcohol ester of a condensed hydroxy fatty acid can be obtained by esterifying the condensed hydroxy fatty acid with an alcohol. The alcohol ester of a condensed hydroxy fatty acid can be obtained, for example, by mixing the condensed hydroxy fatty acid with an alcohol, adding an alkali catalyst such as caustic soda or an acid catalyst such as phosphoric acid to the resulting mixture, and removing reaction water under heating. The degree of esterification during this reaction can be confirmed by measuring the acid value, saponification value, hydroxyl value, etc. The condensation degree of the condensed hydroxy fatty acid used here is also preferably 2 or more, and more preferably 4 or more, as described above.

[0045] Examples of the alcohol include monohydric alcohols such as methyl alcohol, ethyl alcohol, and isopropyl alcohol; and dihydric alcohols such as ethylene glycol and propylene glycol. Polyhydric alcohols may also be used. Examples of polyhydric alcohols include alkane polyols such as pentaerythritol and glycerin; polyalkane polyols, which are polymers of the alkane polyols; sugars such as sucrose; and sugar derivatives, such as sugar alcohols like sorbitol and mannitol. These alcohols may be used alone or in combination of two or more.

[0046] Specific examples of the condensed hydroxy fatty acid and / or its alcohol ester (C) synthesized using the above compounds as raw materials include condensed ricinoleic acid obtained by dehydration condensation of ricinoleic acid, condensed 12-hydroxystearic acid obtained by dehydration condensation of 12-hydroxystearic acid, condensed ricinoleic acid hexaglycerol ester, which is an ester of condensed ricinoleic acid and hexaglycerol of a glycerol 6-polymer, condensed ricinoleic acid tetraglycerol ester, which is an ester of condensed ricinoleic acid and tetraglycerol of a glycerol 4-polymer, condensed 12-hydroxystearic acid propylene glycol ester, which is an ester of condensed 12-hydroxystearic acid and propylene glycol, and condensed linoleic acid propylene glycol ester, which is an ester of condensed ricinoleic acid and propylene glycol, etc. These may be used alone or in combination of two or more.

[0047] The content of the condensed hydroxy fatty acid and its alcohol ester (C) is preferably 0.1 to 10 parts by weight, more preferably 0.2 to 8 parts by weight, even more preferably 0.3 to 5 parts by weight, and even more preferably 0.4 to 5 parts by weight, per 100 parts by weight of the resin in the ultra-high molecular weight stretched film A. Within these ranges, a resin composition with excellent fluidity can be prepared, and an ultra-high molecular weight stretched film A can be obtained in which the properties inherent in the ultra-high molecular weight polyethylene resin (A) are fully exhibited. The "content of the condensed hydroxy fatty acid and its alcohol ester (C)" refers to the total content of the condensed hydroxy fatty acid and the alcohol ester of the condensed hydroxy fatty acid. Therefore, when the ultra-high molecular weight stretched film A contains only condensed hydroxy fatty acid as compound (C), the "content of the condensed hydroxy fatty acid and its alcohol ester (C)" refers to the content of the condensed hydroxy fatty acid. Furthermore, when the ultra-high molecular weight stretched film A contains only an alcohol ester of a condensed hydroxy fatty acid as the compound (C), the "content ratio of the condensed hydroxy fatty acid and its alcohol ester (C)" means the content ratio of the alcohol ester of the condensed hydroxy fatty acid.

[0048] (Other ingredients) The ultrahigh molecular weight stretched film A may further contain any appropriate additives as needed, such as, for example, a flow modifier, an anti-smear agent, a heat stabilizer, a weathering agent, or other stabilizers, a pigment, a dye, or other colorant, a lubricant, a crosslinking agent, a crosslinking aid, an antiblocking agent, an antistatic agent, an antifogging agent, an organic filler, or an inorganic filler.

[0049] Examples of flow modifiers include various silicone oils such as polydimethylsiloxane, liquid lubricants, various aliphatic compounds or their metal salts, alicyclic compounds, various waxes, solid lubricants, various interfacial lubricants, and mixtures thereof. In one embodiment, a fatty acid amide (preferably erucic acid amide) is used as the flow modifier. The content of the fatty acid amide is, for example, 0.05 to 1 part by weight per 100 parts by weight of the resin constituting the ultra-high molecular weight stretched film A. Adding the fatty acid amide in this manner improves the thin film formability of the ultra-high molecular weight stretched film A.

[0050] Examples of silicone oils include dimethylpolysiloxane type, methylhydrogenpolysiloxane type, both-end hydrogenpolysiloxane type, methylphenylpolysiloxane type, alkyl-modified silicone type, amino-modified silicone type, carboxyl-modified silicone type, higher fatty acid-modified silicone type, epoxy-modified silicone type, vinyl group-containing silicone type, alcohol-modified silicone type, polyether-modified silicone type, alkyl-polyether-modified silicone type, and fluorine-modified silicone type silicone oil.

[0051] Examples of liquid lubricants include synthetic lubricating oils such as polyglycol oil, polyphenyl ether oil, ester oil, phosphate ester oil, polychlorotrifluoroethylene oil, fluoroester oil, chlorinated biphenyl oil, and silicone oil, as well as ethylene-α-olefin copolymer synthetic lubricating oil.

[0052] Examples of the aliphatic compounds include fatty acids such as capric acid, lauric acid, myristic acid, palmitic acid, stearic acid, and oleic acid; ethylene bis-stearic acid amide, stearic acid amide, oleic acid amide, erucic acid amide, ethylene bis-oleic acid amide, capric amide, lauric amide, palmitic amide, stearyl amide, behenanamide, hydroxystearic acid amide, N-oleyl palmitic acid amide, N-stearyl stearic acid amide, N-stearyl oleic acid amide, N-oleyl stearic acid amide, N-stearyl erucic acid amide, and methylol stearic acid amide. fatty acid amides such as methylene bisstearic acid amide, ethylene biscapric acid amide, ethylene bislauric acid amide, ethylene bishydroxystearic acid amide, ethylene bisbehenic acid amide, hexamethylene bisstearic acid amide, hexamethylene bisbehenic acid amide, hexamethylene hydroxystearic acid amide, N,N'-distearyl adipamide, N,N'-distearyl sebacic acid amide, ethylene biserucic acid amide, hexamethylene bisoleic acid amide, N,N'-dioleyl adipamide, and N,N'-dioleyl sebacic acid amide; dioctyl ether {(CH 17 )2O}, didecyl ether {(C 10 H 25 )2O}, didodecyl ether {(C 12 H 25 )2O}, dioctadecyl ether {(C 18 H 37 )2O}; methyl tetradecyl ketone {CH3CO(CH2) 13 CH3}, n-propyl hexadecyl ketone {CH3(CH2)2CO(CH2) 15 CH3}, didotesyl ketone {CH3(CH2) 11 CO(CH2) 11 CH3}, dioctadecyl ketone {CH3(CH2) 17 CO(CH2) 17 Ketone compounds of fatty acids such as octyl laurate {CH3(CH2) 10 COO(CH2)7CH3}, ethyl palmitate {CH3(CH2)14 COOCH2CH3}, butyl stearate {CH3(CH2) 16 COO(CH2)3CH3}, octyl stearate {CH3(CH2) 16 COO(CH2)7CH3}; lauric alcohol, myristyl alcohol, cetyl alcohol (CH3(CH2) 14 CH2OH), heptadecyl alcohol (CH3(CH2) 15 CH2OH), stearyl alcohol (CH3(CH2) 16 CH2OH), seryl alcohol (CH3(CH2) 24 CH2OH), behenyl alcohol (CH3(CH2)7C(CH 11 aliphatic alcohols such as CHOH;

[0053] Examples of metal salts of fatty acids include calcium stearate, magnesium stearate, barium stearate, lithium stearate, sodium stearate, zinc stearate, zinc claurate, zinc behenate, calcium montanate, magnesium montanate, barium montanate, lithium montanate, sodium montanate, zinc montanate, calcium behenate, magnesium behenate, barium behenate, lithium behenate, sodium behenate, zinc behenate, calcium laurate, magnesium laurate, barium laurate, lithium laurate, sodium laurate, zinc laurate, calcium 12-hydroxystearate, magnesium 12-hydroxystearate, barium 12-hydroxystearate, lithium 12-hydroxystearate, and sodium 12-hydroxystearate.

[0054] Examples of alicyclic compounds include esterified rosin, cyclic terpene resins, terpene resin derivatives, polycyclopentadiene, hydrogenated polycyclopentadiene, polycyclopentadiene-based resins obtained by polymerizing dicyclopentadiene as the main component with the addition of 1,3-pentadiene or conjugated diolefins, and dicyclopentadiene-based petroleum resins.

[0055] Examples of waxes include n-alkanes having 22 or more carbon atoms, such as n-nonane, n-decane, n-undecane, n-dodecane, n-tetradecane, n-octadecane, docosane, tricosane, tetracosane, and triacontane, or mixtures of these with lower n-alkanes as the main component; so-called paraffin wax separated and refined from petroleum; medium- and low-molecular-weight polymers obtained by copolymerizing ethylene or ethylene with other α-olefins, such as medium- and low-pressure polyethylene waxes, ethylene copolymer waxes, and waxes obtained by reducing the molecular weight of polyethylene by thermal degradation or the like, such as medium- and low-pressure polyethylene and high-pressure polyethylene; and oxides of these waxes, oxidized waxes such as those modified with maleic acid, maleic acid-modified waxes, montanic acid ester waxes, and waxes of fatty acid derivatives (e.g., dicarboxylic acid esters, glycerin fatty acid esters, and amide waxes).

[0056] Examples of solid lubricants include graphite, molybdenum disulfide, boron nitride, tungsten disulfide, lead oxide, glass powder, and metal soap.

[0057] Examples of surfactants include glycerin monostearate, palm hydrogenated oil monoglyceride, oleic acid monoglyceride, rapeseed hydrogenated oil fatty acid mono- and diglyceride, self-emulsifying stearic acid mono- and diglyceride, oleic acid mono- and diglyceride, caprylic acid monoglyceride, lauric acid monoglyceride, capric acid monoglyceride, caprylic acid mono- and diglyceride, caprylic acid diglyceride, diglycerol mono- and dioleate, diglycerol mono- and distearate, diglycerol monostearate, decaglycerol pentaoleate, decaglycerol pentastearate, decaglycerol pentastearate, decaoleate Examples of suitable glycerin include glycerin, decaglycerin decastearic acid, pentaglycerin trioleate, pentaglycerin hexastearate, decaglycerin monolaurate, decaglycerin monomyristate, decaglycerin monooleate, decaglycerin monostearate, decaglycerin distearate, pentaglycerin monolaurate, pentaglycerin monomyristate, pentaglycerin monooleate, pentaglycerin monostearate, sorbitan monostearate, sorbitan monooleate, sorbitan trioleate, propylene glycol monostearate, and propylene glycol monooleate.

[0058] Examples of the anti-smear agent include fluorine-based elastomers, metal salts of 12-hydroxystearic acid, basic metal salts of 12-hydroxystearic acid, and carboxylic acid amide waxes.

[0059] Examples of the antistatic agent include low molecular weight surfactant-type antistatic agents, polymer-type antistatic agents, etc. Examples of the low molecular weight surfactant-type antistatic agents include cationic antistatic agents having cationic groups such as quaternary ammonium salts, pyridinium salts, and primary to tertiary amino groups, anionic antistatic agents having anionic groups such as sulfonate groups, sulfate ester groups, phosphate ester groups, and sulfonate groups, amphoteric antistatic agents such as amino acid antistatic agents and amino sulfate ester antistatic agents, and nonionic antistatic agents such as amino alcohol antistatic agents, glycerin antistatic agents, and polyethylene glycol antistatic agents. Examples of polymer-type antistatic agents include nonionic polymer-type antistatic agents such as polyethylene oxide, polypropylene oxide, polyethylene glycol, polyether ester amide, polyether ester, polyether polyolefin, and ethylene oxide-epichlorohydrin copolymers; anionic polymer-type antistatic agents such as polystyrene sulfonic acid; and cationic polymer-type antistatic agents such as quaternary ammonium base-containing acrylate polymers, quaternary ammonium base-containing styrene polymers, and quaternary ammonium base-containing polyethylene glycol methacrylate copolymers.

[0060] Conductive materials can also be used to provide antistatic properties. Examples of conductive materials include metals, metal oxides, particles coated with metals or metal oxides, inorganic metal salt compounds, carbon-based materials, modified silicone materials, ionic organic compounds, nonionic organic compounds, conductive polymers, and ionic liquids. Examples of metals include gold, silver, platinum, copper, nickel, iron, palladium, aluminum, gallium, indium, and tin. Examples of metal oxides include zinc oxide, antimony oxide, tin oxide, cerium oxide, indium oxide, indium tin oxide (ITO), metal-doped tin oxide, and metal-doped zinc oxide. Examples of metal-doped tin oxides include antimony-doped tin oxide (ATO). Examples of inorganic metal salt compounds include metal silicates, metal titanates, alkali metal sulfates, alkali metal nitrates, alkali metal perchlorates, alkali metal sulfonates, alkali metal carboxylates, metal complexes of tetrafluoroboric acid, and metal complexes of hexafluorophosphate. Examples of carbon-based materials include carbon black, graphite, carbon fiber, carbon nanotubes, fullerenes, and graphene. Examples of conductivity-imparting materials include conductive fillers. Examples of conductive fillers include carbon-based, metal-based, metal oxide-based, and metal-coated conductive fillers. Examples of carbon-based conductive fillers include ketjen black, acetylene black, and oil furnace black. Examples of metals constituting metal-based conductive fillers include Ag, Ni, Cu, Zn, Al, and stainless steel. Examples of metal oxides constituting metal oxide-based conductive fillers include SnO2, In2O3, and ZnO. Examples of metal-coated conductive fillers include fillers that use Ni, Al, or the like as a coating material and mica, glass beads, glass fiber, carbon fiber, calcium carbonate, zinc oxide, titanium oxide, or the like as a base filler.

[0061] In one embodiment, a carbon-based conductive filler (preferably Ketjen black) is used. The content ratio of the carbon-based conductive filler is, for example, 2 to 20 parts by weight per 100 parts by weight of the resin in the resin composition. By adding the carbon-based conductive filler in this way, the surface resistivity (for example, 10 3 Ω / □~10 5 Therefore, a resin composition capable of forming a molded article with an appropriately set elastic modulus (Ω / □) can be obtained.

[0062] Examples of coloring materials include perylene red (CI Pigment Red 178), quinacridone red (CI Pigment 122, 202), anthraquinone yellow (CI Pigment Yellow 147), benzimidazolone yellow (CI Pigment Yellow 180, 181), monoazo lake yellow (CI Pigment Examples of pigments include organic pigments such as titanium dioxide (CI Pigment White 6), zinc sulfide (CI Pigment White 22), carbon black (CI Pigment Black 7), calcined black (CI Pigment Black 28), bismuth vanadate yellow (CI Pigment Yellow 184), nickel titanium yellow (CI Pigment Yellow 53), chrome titanium yellow (CI Pigment Brown 24), red iron oxide (CI Pigment Red 101), chromium oxide (CI Pigment Green 17), cobalt green (CI Pigment Green 19), ultramarine blue (CI Pigment Blue 29), cobalt blue (CI Pigment Blue 28), ultramarine violet (CI Pigment Violet 15), and aluminum (CI Pigment Matal 1).

[0063] (Manufacturing method of ultra-high molecular weight stretched film A) The ultra-high molecular weight stretched film A can be produced by any suitable method, including stretching by melt sheet rolling. Examples of such a production method include preparing the resin composition containing the ultra-high molecular weight polyethylene resin (A) and then melt sheet rolling the resin composition. As described above, the resin composition can further contain a thermoplastic resin (B), a condensed hydroxy fatty acid and / or its alcohol ester (C), and additives added as needed.

[0064] In one embodiment, the resin composition can be prepared by melt-kneading an ultra-high molecular weight polyethylene resin (A), a thermoplastic resin (B), a condensed hydroxy fatty acid and / or its alcohol ester (C), and additives added as needed. Examples of melt-kneading methods include methods using a single-screw extruder, a multi-screw extruder, a tandem extruder, a Banbury mixer, or the like. Melt-kneading the resin in the presence of the condensed hydroxy fatty acid and / or its alcohol ester (C) can suppress the generation of lumps, resulting in a resin composition with a good resin dispersion.

[0065] The processing temperature in the melt-kneading is preferably a temperature at which the resin contained in the resin composition can melt, and the temperature is preferably 120°C to 350°C, more preferably 140°C to 330°C, even more preferably 150°C to 300°C, and particularly preferably 160°C to 250°C.

[0066] Melt sheet rolling refers to a molding method in which a resin composition is rolled between two or more rolls to form a film having a predetermined thickness. Typically, the resin composition is melt-kneaded and released from a T-die, and then subjected to the rolling. In the present invention, the use of melt sheet rolling allows for the production of an ultra-high molecular weight stretched film A having the above-described properties. As the melt sheet rolling method, the polishing roll method used in T-die extrusion molding and calendar molding are preferably used. Examples of T-die extrusion molding include a horizontally arranged roll method and a vertically arranged roll method, and the number of rolls is preferably three or more. Equipment having a mechanism capable of rolling between each roll can be used. Examples of calendar molding devices include a two-roll in-line calendar, a three-roll in-line calendar, a four-roll in-line calendar, an S-type calendar, an inverted L-type calendar, a Z-type calendar, and a diagonal Z-type calendar.

[0067] The lip clearance of the T-die is preferably 0.2 mm to 5 mm, more preferably 1 mm to 3 mm. The temperature at the outlet of the T-die is preferably 150° C. to 300° C., more preferably 200° C. to 280° C. The temperature of the T-die can be adjusted depending on the temperature of the desired resin composition.

[0068] The number of times of rolling may be one or more. By rolling multiple times, it is possible to increase the strength (increase in MD tensile strength and MD modulus) and obtain an ultra-high molecular weight stretched film A with a high degree of crystalline orientation. The number of times of rolling is preferably 2 to 6, and more preferably 2 to 4.

[0069] Preferably, the rolling rolls are heated. The temperature of the rolling rolls is preferably 90° C. to 200° C., more preferably 100° C. to 180° C., and even more preferably 120° C. to 160° C. The temperatures of the multiple rolling rolls may be the same or different.

[0070] The linear pressure applied to the rolling rolls is preferably 15 kg / cm to 300 kg / cm, more preferably 30 kg / cm to 200 kg / cm, and even more preferably 50 kg / cm to 150 kg / cm.

[0071] The processing speed in the calender molding can be set to any appropriate speed.

[0072] The method for producing the ultra-high molecular weight stretched film A may include a stretching step (for example, a roll stretching step, a tenter stretching step, etc.). The stretching step may be carried out, for example, after molten sheet rolling molding. As the stretching method, for example, MD stretching using a roll may be adopted. The MD stretching ratio is, for example, 1.1 to 5 times. By stretching at such a ratio, a polyethylene laminate having good formability and excellent strength can be obtained. Furthermore, the ultra-high molecular weight stretched film A may be obtained by TD stretching, such as tenter stretching, instead of MD stretching.

[0073] The ultra-high molecular weight stretched film A may be subjected to any appropriate surface treatment. For example, by performing a surface treatment, a polyethylene laminate having excellent adhesion between the ultra-high molecular weight stretched film A and the low-molecular weight ethylene resin layer can be obtained. Examples of surface treatments include corona treatment, flame treatment, and plasma treatment.

[0074] The ultra-high molecular weight stretched film A may be subjected to a vapor deposition treatment of aluminum, alumina, silicon dioxide, etc., or may be coated with a gas barrier resin such as polyvinylidene chloride.

[0075] A-2. Anchor coat layer In one embodiment, an anchor coat layer is provided between the ultra-high molecular weight stretched film A and the low-molecular weight ethylene-based resin layer. Such a polyethylene laminate can be obtained by forming a low-molecular weight ethylene-based resin layer on the anchor coat layer of the ultra-high molecular weight stretched film A. The ultra-high molecular weight stretched film A with an anchor coat layer can be obtained by applying any appropriate anchor coating agent to the ultra-high molecular weight stretched film A. Examples of anchor coating agents include polyurethane-based adhesives, isocyanate-based adhesives, polyethyleneimine-based adhesives, and polybutadiene-based adhesives. The polyurethane-based adhesive or isocyanate-based adhesive is preferably an adhesive composed of at least one polyol component having at least two hydroxyl groups in the molecule and at least one polyisocyanate component and / or diisocyanate having at least two isocyanate groups in the molecule. The polyol component can be appropriately selected from polyester polyols, polyether polyols, acrylic polyols, polyolefin polyols, and the like. Examples of diisocyanates include aromatic diisocyanates such as 4,4'-, 2,4'-, and 2,2'-diisocyanatodiphenylmethane, 1,5-diisocyanatonaphthalene, 4,4'-diisocyanatodicyclohexylmethane, 1,4-diisocyanatobenzene, and / or 2,4- or 2,6-diisocyanatotoluene, and aliphatic and alicyclic diisocyanates such as 1,6-diisocyanatohexane, 1,10-diisocyanatodecane, 1,3-diisocyanatocyclopentane, 1,4-diisocyanatocyclohexane, and 1-isocyanato-3,3,5-trimethyl-3 or -5-isocyanatomethanecyclohexane. The polyisocyanate component can be produced from these diisocyanate monomers. Such anchor coating agents can be appropriately selected from commercially available products, and examples of polyurethane adhesives include those available under the trade name Nipporan 3228 from Tosoh Corporation, and examples of polyethyleneimine adhesives include those available under the trade name Toyobine from Tosoh Corporation.

[0076] The thickness of the anchor coat layer is preferably 0.01 μm to 0.7 μm. Within this range, a polyethylene laminate with excellent recyclability can be obtained. The thickness of the anchor coat layer is more preferably 0.01 μm to 0.3 μm, and even more preferably 0.01 μm to 0.1 μm. Within this range, a polyethylene laminate with excellent adhesion between the ultra-high molecular weight stretched film A and the low-molecular weight ethylene resin layer can be obtained.

[0077] A-3. Low-molecular-weight ethylene-based resin layer The thickness (total thickness) of the low-molecular-weight ethylene resin layers is preferably 5 μm to 150 μm, more preferably 10 to 100 μm, and even more preferably 20 μm to 80 μm. Within this range, a polyethylene laminate having excellent adhesion between the ultra-high molecular weight stretched film A and the low-molecular-weight ethylene resin layers can be obtained.

[0078] Any appropriate ethylene-based resin can be used as a material constituting the low-molecular-weight ethylene-based resin layer. The ethylene-based resin may be a homopolymer of ethylene or a copolymer of ethylene and a monomer copolymerizable with ethylene. Examples of ethylene-based resins include high-density polyethylene, ethylene-α-olefin copolymer, high-pressure low-density polyethylene, ethylene-vinyl acetate copolymer, ethylene-unsaturated carboxylic acid copolymer, ethylene-unsaturated carboxylic acid ester copolymer, ethylene-carbon monoxide copolymer, and ethylene-styrene copolymer. In one embodiment, the low-molecular-weight ethylene-based resin layer contains at least one selected from high-pressure low-density polyethylene, ethylene-α-olefin copolymer, ethylene-vinyl acetate copolymer, and ethylene-acrylic acid ester copolymer.

[0079] The production methods for high-density polyethylene and ethylene-α-olefin copolymers are not particularly limited, and examples include high-, medium-, and low-pressure ionic polymerization methods using Ziegler-Natta catalysts, Phillips catalysts, and metallocene catalysts. Such resins can be conveniently selected from commercially available products. For example, they are commercially available from Tosoh Corporation under the trade names Nipolon Hard, Nipolon-L, and Nipolon-Z. Examples of α-olefins constituting ethylene-α-olefin copolymers include propylene, 1-butene, 1-pentene, 1-hexene, 1-heptene, 1-octene, 1-nonene, and 1-decene. High-pressure low-density polyethylene can be produced by high-pressure radical polymerization. Such resins can be conveniently selected from commercially available products, such as those commercially available from Tosoh Corporation under the trade name Petrothene. Ethylene-vinyl acetate copolymers can be produced by known methods such as high-pressure radical polymerization, solution polymerization, and emulsion polymerization. Such resins can be conveniently selected from commercially available products. For example, ethylene-vinyl acetate copolymers are commercially available from Tosoh Corporation under the trade name Ultrathene. Of the ethylene polymers, high-pressure low-density polyethylene, ethylene-α-olefin, and ethylene-vinyl acetate copolymers are preferred due to their excellent adhesive properties, and a mixture of high-pressure low-density polyethylene and ethylene-α-olefin copolymers is particularly preferred due to its excellent adhesive properties and extrusion lamination processability.

[0080] The density of the ethylene resin constituting the low molecular weight ethylene resin is preferably 860 kg / m 3 ~955kg / m 3 and more preferably 870 kg / m 3 ~930kg / m 3 and most preferably 870 kg / m 3 ~915kg / m 3 Within this range, it is possible to form a low-molecular-weight ethylene-based resin layer that has excellent adhesiveness to the ultra-high molecular weight stretched film A. The density of the ethylene-based resin is measured in accordance with JIS K6922-1 (1997).

[0081] The melt flow rate of the ethylene-based resin constituting the low-molecular-weight ethylene-based resin layer is preferably 0.1 g to 30 g / 10 min, more preferably 0.5 g / 10 min to 25 g / 10 min, and even more preferably 3 g / 10 min to 20 g / 10 min. Resins having a melt flow rate in such a range are advantageous in that they have excellent moldability when producing a polyethylene laminate.

[0082] The melting point of the ethylene-based resin constituting the low-molecular-weight ethylene-based resin layer is preferably 50° C. to 140° C., and more preferably 70° C. to 130° C. The melting point of the ethylene-based resin can be measured using a measuring device DSC6220 (manufactured by Seiko Instruments Inc.) by increasing the temperature from an initial temperature of 30° C. to 230° C. at a temperature increase rate of 10° C. / min and a temperature decrease rate of 10° C. / min.

[0083] The low-molecular-weight ethylene-based resin layer may further contain any appropriate additives as necessary. In one embodiment, the low-molecular-weight ethylene-based resin layer may contain a tackifier. By forming a low-molecular-weight ethylene-based resin layer containing a tackifier, a polyethylene laminate having excellent adhesion between the low-molecular-weight ethylene-based resin layer and the ultra-high molecular weight stretched film A can be obtained.

[0084] Examples of the tackifier include petroleum resins such as aliphatic petroleum resins, aliphatic hydrogenated petroleum resins, aromatic petroleum resins, aromatic hydrogenated petroleum resins, alicyclic petroleum resins, alicyclic hydrogenated petroleum resins, and copolymer hydrogenated petroleum resins, as well as coumarone resins, styrene resins, and natural resin-based tackifiers such as rosin resins, methyl ester resins, glycerin ester resins, pentaerythritol ester resins, terpene resins, and modified products thereof. Among these tackifiers, tackifiers consisting of at least one selected from the group consisting of petroleum resins, terpene resins, and rosin resins are preferred from the viewpoint of improving adhesion.

[0085] The tackifier preferably has a softening point measured by the ring and ball method in the range of 90° C. to 140° C., more preferably 100° C. to 135° C., and even more preferably 105° C. to 130° C. When the softening point is within the above range, there is little blocking of the film after molding, and the adhesive strength retention in a low-temperature environment is favorable.

[0086] The tackifier may be commercially available. Specific examples of petroleum resins include (trade names) Arkon P100, Arkon P125, Arkon P140, Arkon M90, Arkon M115, and Arkon M135 (all manufactured by Arakawa Chemical Industries, Ltd.), Imave S110 and Imave P125 (all manufactured by Idemitsu Kosan Co., Ltd.), and T-REZ RC115 and T-REZ HA125 (all manufactured by JXTG Nippon Oil & Energy Corporation). Examples of rosin-based resins include Pine Crystal KE-311 (manufactured by Arakawa Chemical Industries, Ltd.). Examples of terpene-based resins include YS Resin PX1150 and YS Resin PX1150N (manufactured by Yasuhara Chemical Co., Ltd.).

[0087] The content of the tackifier is preferably 1 to 30 parts by weight, more preferably 5 to 40 parts by weight, relative to 100 parts by weight of the ethylene resin constituting the low-molecular-weight ethylene resin layer. Within this range, a polyethylene laminate having excellent adhesion between the low-molecular-weight ethylene resin layer and the ultra-high molecular weight stretched film A can be obtained.

[0088] Examples of other additives include additives typically used in polyolefins, such as antioxidants, lubricants, neutralizing agents, antiblocking agents, surfactants, and slip agents; other thermoplastic resins such as polyolefins; and the like.

[0089] The low-molecular-weight ethylene-based resin layer may have two or more layers, if necessary. When the low-molecular-weight ethylene-based resin layer has two or more layers, the layers may have the same or different configurations. In one embodiment, the polyethylene laminate includes, as the low-molecular-weight ethylene-based resin layer, a high-pressure low-density polyethylene layer and an ethylene-α-olefin copolymer layer. The high-pressure low-density polyethylene layer is advantageous in that it has excellent lamination properties, and the ethylene-α-olefin copolymer layer is advantageous in that it has high heat-seal strength. In another embodiment, the polyethylene laminate includes, as the low-molecular-weight ethylene-based resin layer, a high-pressure low-density polyethylene layer having a density of 910 kg / m 3 It contains the following ethylene-α-olefin copolymer layer and ethylene-1-hexene copolymer or ethylene-1-octene copolymer layer. Density: 910 kg / m 3 The following ethylene-α-olefin copolymer layer is advantageous in that it has excellent adhesion to the ultra-high molecular weight oriented film A, and the ethylene-1-hexene copolymer layer and ethylene-1-octene copolymer layer are advantageous in that they have high heat seal strength.

[0090] B. Manufacturing method of polyethylene laminate The polyethylene laminate can be produced by extruding and laminating a molten film of a composition for forming a low-molecular-weight ethylene-based resin layer (a composition containing an ethylene-based resin) onto the ultra-high molecular weight stretched film A or onto the surface of the anchor coat layer of the ultra-high molecular weight stretched film A provided with an anchor coat layer. Examples of such methods include various extrusion lamination methods such as single lamination, tandem lamination, sandwich lamination, and coextrusion lamination. When the low-molecular-weight ethylene-based resin layer has two or more layers, tandem lamination, sandwich lamination, and coextrusion lamination are particularly preferred. In the extrusion lamination method, the resin temperature is preferably in the range of 200°C to 350°C, and the surface temperature of the cooling roll is preferably in the range of 10°C to 50°C. During extrusion lamination, ozone gas may be sprayed to achieve good adhesion. In this case, the temperature of the ethylene-based polymer extruded from the die is preferably 200°C or higher. The amount of ozone gas to be treated was determined based on the amount of ozone gas per 1 m of the film made of the resin composition for extrusion lamination of the present invention extruded from the die. 2 It is preferable that the amount is 0.5 mg or more per unit area.

[0091] C. complex In one embodiment, the polyethylene laminate may be laminated with other films as needed. Examples of other films include polypropylene films, polyester films such as polyethylene terephthalate and polybutylene terephthalate, polyamide films such as nylon 6 and nylon 66, saponified ethylene-vinyl acetate copolymer films, polyvinyl alcohol films, polyvinyl chloride films, polyvinylidene chloride films, polycarbonate films, and cellulose-based films. When a layer made of a material other than polyethylene-based resin is provided, the content of the material other than polyethylene-based resin in the polyethylene laminate is preferably 10 wt % or less.

[0092] Furthermore, other films may be subjected to vapor deposition treatment of aluminum, alumina, silicon dioxide, etc., or may be coated with a gas barrier resin such as polyvinylidene chloride.

[0093] D. Recycling of polyethylene laminates (recycled polyethylene pellets) The polyethylene laminate has excellent recyclability because a large portion thereof is made up of polyethylene-based materials. In one embodiment, there is provided recycled polyethylene pellets composed of the heat-sealable polyethylene laminate. The recycled polyethylene pellets may be pellets obtained by regenerating the heat-sealable polyethylene laminate by any appropriate method. Examples of recycling methods include a material recycling method in which the polyethylene laminate is melt-kneaded to obtain pellets, and chemical recycling in which the polyethylene laminate is thermally decomposed to obtain low-molecular-weight hydrocarbons. Material recycling is particularly preferred because of its low cost and low energy requirements.

[0094] The melt-kneading device used for recycling the polyethylene laminate is not particularly limited as long as it can uniformly disperse the polyethylene laminate, and any commonly used resin kneading device can be used. For example, kneading devices such as a single-screw extruder, a twin-screw extruder, a multi-screw extruder, a Banbury mixer, a pressure kneader, a rotating roll, and an internal mixer can be used. Among these, a twin-screw extruder is more preferred because of its excellent dispersibility and continuous productivity.

[0095] When kneading is performed using a twin-screw extruder, the screw rotation speed is not particularly limited, but is preferably 50 rpm to 3000 rpm, more preferably 300 rpm to 3000 rpm. A screw rotation speed of 50 rpm or more is preferred because the dispersibility of the mixed components is improved and the resulting resin has excellent physical properties, while a screw rotation speed of 3000 rpm or less is preferred because the resin does not deteriorate due to excessive shear heat generation, and the resulting pellets have excellent physical properties.

[0096] When an extruder is used in the kneading step, a resin composition kneaded in the extruder, preferably a resin composition kneaded under high-speed shear conditions of 50 rpm to 3000 rpm, can be used as a raw material. In addition, a molded article obtained by extrusion molding in the extruder can be used as a molded product.

[0097] The recycled polyethylene pellets may contain additives such as antistatic agents, light stabilizers, ultraviolet absorbers, nucleating agents, lubricants, antioxidants, antiblocking agents, flow improvers, mold release agents, flame retardants, colorants, inorganic neutralizing agents, hydrochloric acid absorbers, filler conductive agents, chain extenders, and hydrolysis inhibitors, as long as the effects of the present invention are not impaired. [Example]

[0098] The present invention will be described in more detail below with reference to examples, but the present invention is not limited to these examples. All parts and percentages are based on weight unless otherwise specified. The evaluation methods used in the examples and comparative examples are as follows. [Crystal orientation] Two-dimensional wide-angle X-ray diffraction measurements were performed using a SmartLab (manufactured by Rigaku Corporation) measuring device and CuKα radiation as the X-ray source. From the obtained wide-angle diffraction image, the azimuth angle distribution curve originating from the (110) plane at 2θ was determined, and the half-widths of the peaks at 0° and 180° were measured, and the degree of crystal orientation was calculated using the following formula. Crystal orientation degree = (360 - half-width x 2) / 360 [Tensile strength] Measurements were made using a measuring instrument EZ-SX (manufactured by Shimadzu Corporation) in accordance with JIS K7161. The measurement temperature was 23°C. Elasticity Modulus Measurements were made using a measuring instrument EZ-SX (manufactured by Shimadzu Corporation) in accordance with JIS K7161. The measurement temperature was 23°C. [Moisture permeability] Using the measuring instrument L80-5000 (manufactured by Lyssy), the amount of water vapor (g) passing through an 80 mm diameter sample in 24 hours was measured at a temperature of 40°C and a humidity of 90% RH in accordance with the moisture permeability test (moisture sensor method) of JIS K7129. The measurement temperature was 23°C. [DSC measurement] Using a measuring device DSC6220 (Seiko Instruments Inc.), the temperature was raised from a starting temperature of 30°C to 230°C at a heating rate of 10°C / min and a cooling rate of 10°C / min, held at 230°C for 3 minutes, then cooled to 30°C and again raised to 230°C. [Melt Mass Flow Rate] Measurement was carried out using a melt indexer (manufactured by Takara Kogyo Co., Ltd.) based on JIS K6924-1 (under conditions of 190°C and a load of 2160 g). [Density of ethylene resin] Measurements were made in accordance with JIS K6922-1 (1997). [Adhesive strength] Using a tensile tester (ORIENTEC Tensilon RTE-1210), the stretched film layer and the low-molecular-weight ethylene-based resin layer were peeled at 180° with a sample width of 15 mm and a pulling rate of 300 mm / min, and the strength was measured at a temperature of 23°C. [Heat seal strength] Using a hot tack tester (manufactured by Tester Sangyo), the low-molecular-weight ethylene-based resin layers were brought into contact with each other and heat-sealed by heating from above and below at a sealing temperature of 130°C, a sealing pressure of 0.2 MPa, and a sealing time of 1 second. Then, at an ambient temperature of 23°C, a tensile tester (manufactured by ORIENTEC, Tensilon RTE-1210) was used to measure the heat seal strength at 180° peeling, with a sample width of 15 mm and a pulling speed of 300 mm / min. [Tear strength] Measurement was carried out using an Elmendorf tear strength tester (manufactured by Toyo Seiki Co., Ltd.) in accordance with JIS K7128-2. [Impact strength] Measurement was carried out using a Film Impact Tester (manufactured by Toyo Seiki) in accordance with JIS P8134. [Recyclability] The laminate obtained in each example was cut and melt-extruded at 200°C in a twin-screw extruder (manufactured by Technovel Co., Ltd.), and the appearance of the resulting strand was evaluated. When no protruding foreign matter was observed, the recyclability was evaluated as excellent (◯), and when a significant amount of protruding foreign matter was observed, the recyclability was evaluated as poor (×). When a small amount of such foreign matter was observed, the recyclability was evaluated as △.

[0099] [Example 1] A resin composition was obtained by mixing 59 parts by weight of ultra-high molecular weight polyethylene A1 (manufactured by Asahi Kasei Corporation, product name Sunfine UH850) having a viscosity average molecular weight of 2,000,000, 39 parts by weight of thermoplastic resin B1 (polyethylene, manufactured by Asahi Kasei Corporation, product name "Suntech J300P", MFR 40 g / 10 min), and 2 parts by weight of compound C1 (condensed tetraglycerol ricinoleate; condensation degree of hydroxy fatty acid 10). This resin composition was melted in a single-screw extruder (cylinder temperature 230°C) and extruded through a T-die (lip clearance 2 mm, width 700 mm, die temperature 240°C). The molten sheet was fed into a calendar roll (roll temperature 150°C) and rolled (linear pressure 80 kg / cm, processing speed 3 m / min) with the first and second rolls immediately below the T-die to obtain an ultra-high molecular weight stretched film (thickness: 30 μm). Ethylene-1-hexene copolymer (manufactured by Tosoh Corporation, product name "Nipolon ZZF230-1", MFR: 2 g / 10 min, density: 920 kg / m 3 The mixture was then extruded into a film using an inflation extrusion machine (Placo Corporation) to obtain an ethylene-1-hexene copolymer film having a thickness of 50 μm. Between the ultra-high molecular weight stretched film and the ethylene-1-hexene copolymer film (low molecular weight ethylene-based resin layer (II)), a low-density polyethylene (manufactured by Tosoh Corporation, trade name "Petrothene 203", MFR: 8 g / 10 min, density: 919 kg / m) was used as a composition for forming the low molecular weight ethylene-based resin layer (I). 3 ) was subjected to sandwich lamination molding (processing temperature: 330°C, processing speed: 50 m / min) using an extrusion laminator (manufactured by Sumitomo Heavy Industries Modern Co., Ltd.) to obtain a polyethylene laminate (ultra-high molecular weight stretched film / low-molecular weight ethylene-based resin layer (I) (thickness: 30 μm) / low-molecular weight ethylene-based resin layer (II) (thickness: 50 μm)).

[0100] [Example 2] An ultra-high molecular weight stretched film was obtained in the same manner as in Example 1. The surface of this ultra-high molecular weight stretched film was treated with a corona treatment machine (manufactured by Kasuga Electric Co., Ltd.) at 1.3 W / m 2 A corona treatment was carried out under the condition of 100 s.h to obtain an ultra-high molecular weight stretched film (thickness: 30 μm). Except for using this ultra-high molecular weight stretched film as the ultra-high molecular weight stretched film, a polyethylene laminate (ultra-high molecular weight stretched film / low-molecular weight ethylene-based resin layer (I) (thickness: 30 μm) / low-molecular weight ethylene-based resin layer (II) (thickness: 50 μm)) was obtained in the same manner as in Example 1. The ultra-high molecular weight stretched film was arranged so that the corona-treated surface of the film faced the low-molecular weight ethylene-based resin layer side.

[0101] [Example 3] As a composition for forming the low-molecular-weight ethylene-based resin layer (I), an ethylene-1-butene copolymer (manufactured by Tosoh Corporation, trade name "Lumitack BL600K", MFR: 21 g / 10 min, density: 900 kg / m 3 A polyethylene laminate (ultra-high molecular weight stretched film / low-molecular weight ethylene-based resin layer (I) (thickness: 30 μm) / low-molecular weight ethylene-based resin layer (II) (thickness: 50 μm)) was obtained in the same manner as in Example 1, except that 20 μm thick ethylene-based resin layer (II) (thickness: 50 μm) was used.

[0102] [Example 4] An ultra-high molecular weight stretched film was obtained in the same manner as in Example 1. The surface of this ultra-high molecular weight stretched film was treated with a corona treatment machine (manufactured by Kasuga Electric Co., Ltd.) at 1.3 W / m 2 A corona treatment was carried out under the condition of 100 s.h to obtain an ultra-high molecular weight stretched film (thickness: 30 μm). A polyethylene laminate (ultra-high molecular weight stretched film / low-molecular weight ethylene-based resin layer (I) (thickness: 30 μm) / low-molecular weight ethylene-based resin layer (II) (thickness: 50 μm)) was obtained in the same manner as in Example 3, except that this ultra-high molecular weight stretched film was used as the ultra-high molecular weight stretched film. The ultra-high molecular weight stretched film was arranged so that the corona-treated surface of the film faced the low-molecular weight ethylene-based resin layer side.

[0103] [Example 5] An ultra-high molecular weight stretched film was obtained in the same manner as in Example 1. The surface of this ultra-high molecular weight stretched film was treated with a corona treatment machine (manufactured by Kasuga Electric Co., Ltd.) at 1.3 W / m 2 A corona treatment was performed under conditions of 100 sq. m / s to obtain an ultra-high molecular weight stretched film (thickness: 30 μm). An anchor coating agent (a mixture of Mitsui Chemicals' products "Takelac A3210" and "Takenate A3072") was applied to the corona-treated surface of this ultra-high molecular weight stretched film to a coating thickness of 0.2 μm to obtain an ultra-high molecular weight stretched film (thickness: 30 μm) with an anchor coating layer. A polyethylene laminate (ultra-high molecular weight stretched film / anchor coat layer (thickness: 0.2 μm) / low-molecular weight ethylene-based resin layer (I) (thickness: 30 μm) / low-molecular weight ethylene-based resin layer (II) (thickness: 50 μm)) was obtained in the same manner as in Example 1, except that this ultra-high molecular weight stretched film was used as the ultra-high molecular weight stretched film.

[0104] [Example 6] As a composition for forming the low-molecular-weight ethylene-based resin layer (I), an ethylene-α-olefin copolymer (manufactured by Tosoh Corporation, trade name "Lumitack BL600K", MFR: 21 g / 10 min, density: 900 kg / m 3 A film composed of a polyethylene laminate (ultra-high molecular weight oriented film / low-molecular weight ethylene-based resin layer (I) (thickness: 30 μm) / low-molecular weight ethylene-based resin layer (II) (thickness: 50 μm)) was obtained in the same manner as in Example 1, except that a mixture of 90 parts by weight of an ultra-high molecular weight stretched film / low-molecular weight ethylene-based resin layer (I) (thickness: 30 μm) / low-molecular weight ethylene-based resin layer (II) (thickness: 50 μm)) was used.

[0105] [Example 7] A resin composition was obtained by mixing 60 parts by weight of ultra-high molecular weight polyethylene A2 (manufactured by Celanese Corporation, product name GUR4012) having a viscosity average molecular weight of 1.2 million, 39 parts by weight of thermoplastic resin B1 (polyethylene, manufactured by Asahi Kasei Corporation, product name Suntech J300P, MFR 40 g / 10 min), and 1 part by weight of compound C1 (condensed tetraglycerol ricinoleate; condensation degree of hydroxy fatty acid 10). An ultra-high molecular weight stretched film (thickness: 30 μm) was obtained in the same manner as in Example 5, except that this resin composition was used. A film composed of a polyethylene laminate (ultra-high molecular weight stretched film / anchor coat layer (thickness: 0.2 μm) / low-molecular weight ethylene-based resin layer (I) (thickness: 30 μm) / low-molecular weight ethylene-based resin layer (II) (thickness: 50 μm)) was obtained in the same manner as in Example 1, except that this ultra-high molecular weight stretched film was used as the ultra-high molecular weight stretched film.

[0106] [Example 8] In the same manner as in Example 1, an ultra-high molecular weight stretched film was obtained. This ultra-high molecular weight stretched film and an ethylene-1-hexene copolymer (manufactured by Tosoh Corporation, trade name "Nipolon Z-HL610K", MFR: 21 g / 10 min, density: 910 kg / m) were used as a composition for forming a low molecular weight ethylene-based resin layer. 3 ) was extrusion laminated (processing temperature: 330°C, processing speed: 50 m / min) using an extrusion laminator (manufactured by Sumitomo Heavy Industries Modern Co., Ltd.) to obtain a polyethylene laminate (ultra-high molecular weight stretched film / low molecular weight ethylene-based resin layer (thickness: 50 μm)).

[0107] [Example 9] An ultra-high molecular weight stretched film was obtained in the same manner as in Example 1. An anchor coating agent (a mixture of "Takelac A3210" and "Takenate A3072" manufactured by Mitsui Chemicals, Inc.) was applied to the surface of this ultra-high molecular weight stretched film to a coating thickness of 0.2 μm to obtain an ultra-high molecular weight stretched film (thickness: 30 μm) with an anchor coating layer. A polyethylene laminate (ultra-high molecular weight stretched film / anchor coat layer (thickness: 0.2 μm) / low-molecular weight ethylene-based resin layer (thickness: 50 μm)) was obtained in the same manner as in Example 8, except that this ultra-high molecular weight stretched film was used as the ultra-high molecular weight stretched film.

[0108] [Example 10] A polyethylene laminate was obtained in the same manner as in Example 5, except that an anchor coating agent (manufactured by Tosoh Corporation, trade name "Toyobain 210K") was used as the anchor coating agent and the thickness of the anchor coating layer was set to 0.05 μm.

[0109] [Comparative Example 1] A resin composition made of high-density polyethylene A3 (manufactured by Tosoh Corporation, trade name "Nipolon Hard 7300") having a viscosity-average molecular weight of 210,000 was prepared. A film was obtained in the same manner as in Example 1, except that this resin composition was used.

[0110] Comparative Example 2 A resin composition was obtained by mixing 59 parts by weight of ultra-high molecular weight polyethylene A4 (manufactured by Asahi Kasei Corporation, product name Sunfine UH650) having a viscosity average molecular weight of 1,000,000, 39 parts by weight of thermoplastic resin B1 (polyethylene, manufactured by Asahi Kasei Corporation, product name "Suntech J300P", MFR 40 g / 10 min), and 0.5 parts by weight of compound C (condensed tetraglycerol ricinoleate; condensation degree of hydroxy fatty acid 10). This resin composition was melted in a single-screw extruder, extruded through a ring-shaped die, and subjected to inflation molding to obtain an unstretched film. Ethylene-1-hexene copolymer (manufactured by Tosoh Corporation, product name "Nipolon ZZF230-1", MFR: 2 g / 10 min, density: 920 kg / m 3 The mixture was then extruded into a film using an inflation extrusion machine (Placo Corporation) to obtain an ethylene-1-hexene copolymer film having a thickness of 50 μm. Between the obtained unstretched film and the ethylene-1-hexene copolymer film (low-molecular-weight ethylene-based resin layer (II)), a low-density polyethylene (manufactured by Tosoh Corporation, trade name "Petrothene 203", MFR: 8 g / 10 min, density: 919 kg / m) was used as a composition for forming the low-molecular-weight ethylene-based resin layer (I). 3 ) was subjected to sandwich lamination molding (processing temperature: 330°C, processing speed: 50 m / min) using an extrusion laminator (manufactured by Sumitomo Heavy Industries Modern Co., Ltd.) to obtain a polyethylene laminate (unstretched film / low-molecular-weight ethylene-based resin layer (I) (thickness: 30 μm) / low-molecular-weight ethylene-based resin layer (II) (thickness: 50 μm)).

[0111] Comparative Example 3 A resin composition was obtained by mixing 59 parts by weight of ultra-high molecular weight polyethylene A1 (manufactured by Asahi Kasei Corporation, product name Sunfine UH850) having a viscosity average molecular weight of 2,000,000, 39 parts by weight of thermoplastic resin B1 (polyethylene, manufactured by Asahi Kasei Corporation, product name Suntech J300P, MFR 40 g / 10 min), and 2 parts by weight of compound C1 (condensed tetraglycerol ricinoleate; condensation degree of hydroxy fatty acid 10). This resin composition was melted in a single-screw extruder (cylinder temperature 230°C) and extruded through a T-die (lip clearance 2 mm, width 700 mm, die temperature 240°C). The molten sheet was fed into a calendar roll (roll temperature 150°C) and rolled (linear pressure 80 kg / cm, processing speed 3 m / min) with the first and second rolls immediately below the T-die to obtain a stretched film.

[0112] [Reference example] A film was obtained in the same manner as in Example 5, except that a biaxially oriented polyamide film (manufactured by Toyobo Co., Ltd., product name: Toyobo Harden Film N1102) was used instead of the ultra-high molecular weight oriented film A1. This film is not composed of a single resin and is therefore poorly recyclable.

[0113] <Evaluation> The polyethylene laminates obtained in the Examples, Comparative Examples, and Reference Examples were subjected to the following evaluations, and the results are shown in Table 1.

[0114] [Table 1]

[0115] As is clear from Table 1, the polyethylene laminate of the present invention has excellent heat sealability and is also excellent in physical properties such as strength and impact resistance. Furthermore, since the polyethylene laminate of the present invention has a multilayer structure made of the same type of resin, it also has excellent recyclability.

[0116] This application claims priority from Japanese Patent Application No. 2020-098748, filed June 5, 2020, the entire disclosure of which is hereby expressly incorporated by reference. [Industrial Applicability]

[0117] The polyethylene laminate of the present invention is an easily recyclable material that has excellent adhesive properties in addition to rigidity, strength, and impact resistance, and can be used as a wide range of packaging materials such as refill pouches, bags for heavy items such as rice and liquids, and containers. [Explanation of symbols]

[0118] 10. Ultra-high molecular weight polyethylene resin stretched film 20 Low molecular weight ethylene resin layer 21 Low molecular weight ethylene resin layer (I) 22 Low molecular weight ethylene resin layer (II) 30 Anchor coat layer 100, 200, 300 Heat-sealable polyethylene laminate

Claims

1. a stretched film of an ultra-high molecular weight polyethylene resin (A) having a viscosity average molecular weight of 300,000 to 15,000,000; a low-molecular-weight ethylene-based resin layer composed of an ethylene-based resin, which is disposed on at least one side of the stretched film of the ultra-high-molecular-weight polyethylene-based resin (A), the low-molecular-weight ethylene-based resin layer comprises a high-pressure low-density polyethylene layer and an ethylene-α-olefin copolymer layer; Heat-sealable polyethylene laminate.

2. 2. The heat-sealable polyethylene laminate according to claim 1, further comprising an anchor coat layer between the stretched film of the ultra-high molecular weight polyethylene resin (A) and the low-molecular weight ethylene resin layer.

3. 3. The heat-sealable polyethylene laminate according to claim 2, wherein the anchor coat layer has a thickness of 0.01 μm to 0.7 μm.

4. The heat-sealable polyethylene laminate according to any one of claims 1 to 3, wherein the stretched film of ultra-high molecular weight polyethylene resin satisfies all of the following properties (i) to (iv): (i) a tensile strength at 23°C of 100 MPa or more; (ii) the tensile modulus at 23°C is 1500 MPa or more; (iii) 30 μm equivalent moisture permeability is 15 g / m ２ - d or less, and (iv) In DSC measurement, it has an endothermic peak below 140°C and an endothermic peak of 140°C or higher, and the endothermic peak of 140°C or higher decreases or disappears during the second temperature increase.

5. The stretched film of the ultra-high molecular weight polyethylene resin (A) is The ultra-high molecular weight polyethylene resin (A), and (C) a condensed hydroxy fatty acid and / or an alcohol ester thereof, 5. The heat-sealable polyethylene laminate according to claim 1.

6. 6. The heat-sealable polyethylene laminate according to claim 5, wherein the content of the condensed hydroxy fatty acid and / or its alcohol ester (C) is 0.1 to 10 parts by weight per 100 parts by weight of resin in the stretched film of the ultra-high molecular weight polyethylene resin.

7. The stretched film of the ultra-high molecular weight polyethylene resin (A) is The ultra-high molecular weight polyethylene resin (A), and a thermoplastic resin (B), 7. The heat-sealable polyethylene laminate according to claim 1.

8. The density of the ethylene-based resin constituting the low-molecular-weight ethylene-based resin layer is 860 kg / m ３ ~955 kg / m ３ 8. The heat-sealable polyethylene laminate according to claim 1, wherein

9. The low-molecular-weight ethylene-based resin layer comprises a tackifier, The heat-sealable polyethylene laminate according to any one of claims 1 to 8, wherein the content of the tackifier is 1 part by weight to 30 parts by weight per 100 parts by weight of the ethylene-based resin constituting the low-molecular-weight ethylene-based resin layer.

10. 10. The heat-sealable polyethylene laminate according to claim 9, wherein the tackifier is at least one selected from the group consisting of petroleum resins, terpene resins, and rosin-based resins.

11. A recycled polyethylene pellet comprising the heat-sealable polyethylene laminate according to any one of claims 1 to 10.

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