Laminate and packaging material

Abstract

To provide a laminate which is excellent in both good adhesion to a base material and easy opening handleability such as good easy tearability, and a packaging material.SOLUTION: A laminate has at least four layers of a base material layer 1, a resin layer and an adhesive layer, and a base material layer 2, wherein the four layers are laminated so as to be adjacent to each other, and satisfy the following characteristics. Base material layer 1: oxygen permeability at 20°C and 65%RH of 1,300 mL / m2 day MPa or less. Resin layer: containing a polyethylene resin composition (B) containing a dicarboxylic acid anhydride group-containing polar ethylenic copolymer (A) having the following characteristic (a). (a) The (A) contains a constitutional unit m derived from ethylene and a constitutional unit n derived from a monomer having a dicarboxylic acid anhydride group as essential constitutional units, and contains 0.5 wt.% or more of a constitutional unit n derived from a monomer having a dicarboxylic acid anhydride group as an essential accessory component. Adhesive layer: containing a reactant of a polyol compound and a polyisocyanate compound. Base material layer 2: base material containing an antistatic agent.SELECTED DRAWING: None

Description

[Technical Field]

[0001] The present invention relates to a laminate and a packaging material, and more particularly to a laminate including a first base material layer, a resin layer containing a polyethylene resin composition made of a specific ethylene-based copolymer or the like, an adhesive layer containing a reaction product of a specific compound, and a second base material layer, and a packaging material using the laminate. [Background technology]

[0002] Conventionally, to improve the shelf life of the contents of packages, containers, etc., laminates have been used that are made up of metal foils such as aluminum with barrier properties, plastic films vapor-deposited with metals, inorganic or organic materials, plastic films or paper substrates with barrier coatings, films made of barrier materials such as ethylene-vinyl alcohol copolymers, or laminated films made from the same or different materials. These laminates have traditionally used polyethylene resin compositions, such as high-pressure low-density polyethylene (LDPE) and ethylene-vinyl acetate copolymer (EVA), as heat-sealable layers. In recent years, linear low-density polyethylene (LLDPE), particularly LLDPE polymerized with a metallocene catalyst, has been proposed for use as a sealant in flexible packaging and liquid cartons, among other applications, to improve the heat-seal strength, low-temperature heat-sealability, hot tack, impact resistance, and pinhole resistance of these laminates. However, in tearable packaging applications, LLDPE presents problems such as the need for force to open the container and stretching of the resin layer due to its poor tearability. Additionally, it presents problems such as poor penetration of straws into containers with straw holes, such as liquid cartons.

[0003] These laminates are manufactured using dry lamination, coextrusion molding, and extrusion lamination molding. In extrusion lamination molding, adhesive may or may not be applied, and in either case, stable high adhesive strength is required. Many attempts have been made to solve these problems. For example, a laminate of LLDPE polymerized with a metallocene catalyst and LLDPE polymerized with a Ziegler catalyst has been proposed (see Patent Document 1). However, although the tear resistance of this laminate is somewhat improved by the LLDPE polymerized with a Ziegler catalyst, the elongation of the LLDPE layer polymerized with a metallocene catalyst remains unresolved, and above all, heat sealability is significantly sacrificed, making this method undesirable. Furthermore, there is no description regarding adhesion to substrates. Furthermore, an invention has been proposed in which LDPE having a specific swell ratio is blended with LLDPE polymerized with a metallocene catalyst (see Patent Document 2), but the balance between heat seal strength and tear resistance is not satisfactory, and Patent Document 2 does not mention adhesion to substrates. Furthermore, Patent Document 3 filed by the present applicant also discloses an invention in which an ethylene terpolymer essentially consisting of ethylene, propylene, and 1-hexene or 1-octene is blended with LDPE (see Patent Document 3), but there is no description regarding pierceability and adhesiveness. As a method that does not use an adhesive, a method that uses a polyethylene resin that exhibits specific physical properties or that contains a specific copolymer (see Patent Document 4) has been proposed, but Patent Document 4 does not include any description regarding adhesive strength and tear resistance, and does not disclose any method that is excellent in both adhesive strength and tear resistance. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Application Publication No. 10-24539 [Patent Document 2] Japanese Patent Application Laid-Open No. 2000-212339 [Patent Document 3] Japanese Patent Application Laid-Open No. 2006-82547 [Patent Document 4] Japanese Patent Application Laid-Open No. 2001-191452 Summary of the Invention [Problem to be solved by the invention]

[0005] In view of the above problems, an object of the present invention is to provide a laminate that is excellent in both good adhesion to a substrate and good tearability and other easy-to-open and easy-to-handle properties, and a packaging material using the laminate. [Means for solving the problem]

[0006] As a result of intensive research conducted by the present inventors to solve the above-mentioned problems, they found that a laminate having at least four layers, in which a resin layer is made of a polyethylene resin composition containing a specific dicarboxylic anhydride group-containing polar ethylene copolymer, and an adhesive layer is formed containing a reaction product of a polyol compound and a polyisocyanate compound, has excellent adhesiveness and also excellent tearability, and thus provides a laminate that is excellent in both content protection performance and handleability, thereby completing the present invention.

[0007] That is, the present invention has the following configuration. [1] At least four layers are provided: a base layer 1 (a), a resin layer (b), an adhesive layer (c), and a base layer 2 (d); A laminate in which a base layer 1 (a), a resin layer (b), an adhesive layer (c), and a base layer 2 (d) are laminated adjacent to each other, each of which satisfies the following properties: Base layer 1 (a): Oxygen permeability is 1300 mL / m at 20°C and 65% RH 2 ·day·MPa or less. Resin layer (ii): Contains a polyethylene resin composition (B) containing a dicarboxylic anhydride group-containing polar ethylene copolymer (A) having the following characteristic (a): (a) Contains, as essential structural units, a structural unit (m) derived from ethylene and a structural unit (n) derived from a monomer having a dicarboxylic acid anhydride group, and contains, as an essential secondary component, 0.5% by weight or more of the structural unit (n) derived from a monomer having a dicarboxylic acid anhydride group. Adhesive layer (c): Contains a reaction product of a polyol compound and a polyisocyanate compound. Base layer 2 (d): A base material containing an antistatic agent [2] The laminate according to [1], wherein the polyethylene resin composition (B) further contains a polyethylene resin (C) having the following properties (c-1) to (c-7): (c-1) MFR (190°C, 21.18N load) is 0.1 to 100g / 10min (c-2) In DSC, the total heat of fusion ΔHm is 30 to 120 J / g (c-3) Crystallization temperature Tc is 25 to 90°C (c-4) Contains 80 to 98 mol% of structural units derived from ethylene as a major component, 2 to 20 mol% of structural units derived from propylene as an essential minor component, and may contain up to 5 mol% of structural units derived from a third α-olefin other than ethylene and propylene as a minor component. (However, when the structural units derived from the third α-olefin are contained, the total amount of the structural units derived from ethylene, the structural units derived from propylene, and the structural units derived from the third α-olefin does not exceed 100 mol %). (c-5) Density: 0.88 to 0.94 g / cm 3 (c-6) Polyethylene resin (C) with a total amount of vinyl and vinylidene of 0.35 (pieces / total 1000C) or more (Note that the number of vinyl and vinylidene units is the number per 1,000 carbon atoms in the main chain and side chains measured by NMR.) (c-7) The number of branches (Y) due to comonomers in the polyethylene resin (C) and the density (X) satisfy the relationship of the following formula (1). Formula (1): (Y)≧-1157×(X)+1084 (where Y is the number per 1,000 carbon atoms in total in the main chain and side chains measured by NMR.) [3] The laminate according to [1] or [2], wherein the polyethylene resin composition (B) further contains a polyethylene resin (D) having the following properties (d-1) to (d-2): (d-1) MFR (190°C, 21.18 N load) is 0.1 to 100 g / 10 min (d-2) Density: 0.91 to 0.97 g / cm 3 [4] The laminate according to any one of [1] to [3], wherein the polar ethylene copolymer (A) is a polar group-containing ethylene copolymer of ethylene and an α,β-unsaturated carboxylic acid anhydride produced using a high-pressure radical polymerization process. [5] The laminate according to any one of [1] to [4], wherein the base layer 1(a) is a metal foil or a metal-deposited film. [6] The laminate according to any one of [1] to [5], wherein the laminate is formed by an extrusion coating method. [7] A packaging material comprising the laminate according to any one of [1] to [6]. [Effects of the Invention]

[0008] The laminate of the present invention and packaging materials using the laminate exhibit good adhesion to substrates and easy tearability, and are laminates with excellent protection performance for contents and excellent handling properties when opened. In addition, the improved adhesive strength also enables the high-speed processability of the laminate to be improved. DETAILED DESCRIPTION OF THE INVENTION

[0009] The present invention provides a laminate having at least four layers, namely, a substrate layer 1 (a), a resin layer (b), an adhesive layer (c), and a substrate layer 2 (d), in which the substrate layer 1 (a), the resin layer (b), the adhesive layer (c), and the substrate layer 2 (d) are laminated adjacent to one another, and the laminate contains the resin layer (b) containing a polyethylene resin composition (B) that contains a dicarboxylic acid anhydride group-containing polar ethylene copolymer (A) having the following characteristic (a), the adhesive layer (c) containing a specific compound, and the substrate layer 2 (d) that is a substrate containing an antistatic agent. The present invention will be described in detail below for each item.

[0010] 1. Polyethylene resin composition (B) (1) Polar ethylene copolymer (A) The dicarboxylic acid anhydride group-containing polar ethylene copolymer (A) (also referred to as "polar ethylene copolymer (A)") is a copolymer containing (a) a structural unit (m) derived from ethylene and a structural unit (n) derived from a monomer having a dicarboxylic acid anhydride group as essential structural units. The structural unit (m) derived from ethylene and the structural unit (n) derived from a monomer having a dicarboxylic acid anhydride group are essential structural units, and may further include a structural unit (p) that is a compound having one or more carbon-carbon double bonds in its molecular structure as a structural unit. There are two types of polar ethylene copolymers with different molecular structures depending on the polymerization method: a branched polar ethylene copolymer (A) having a branched molecular structure polymerized by radical polymerization, and a linear polar ethylene copolymer polymerized by catalytic polymerization, which has been newly developed in recent years. Either of these can be used as the polar ethylene copolymer (A) of the present invention.

[0011] (1) Structural unit (m) The structural unit (m) essentially contains a structural unit derived from ethylene, and may further contain one or more structural units derived from an α-olefin having 3 to 20 carbon atoms, as required. The structural units derived from ethylene in the structural units (m) may account for 65 to 100 mol % or 70 to 100 mol % based on the total moles of the structural units (m).

[0012] (2) Structural unit (n) The structural unit (n) is a structural unit derived from a monomer having a dicarboxylic acid anhydride group. The copolymer is characterized in that it contains, as an essential secondary component, a structural unit (n) derived from a monomer having a dicarboxylic acid anhydride group in an amount of 0.5% by weight or more, preferably 1.0% by weight or more. There is no particular upper limit, but it is preferably 30% by weight or less, and even more preferably 10% by weight or less.

[0013] Examples of monomers having a dicarboxylic acid anhydride group include unsaturated dicarboxylic acid anhydrides such as maleic anhydride, itaconic anhydride, citraconic anhydride, tetrahydrophthalic anhydride, 5-norbornene-2,3-dicarboxylic anhydride, 3,6-epoxy-1,2,3,6-tetrahydrophthalic anhydride, tetracyclo[6.2.1.13,6.02,7]dodec-9-ene-4,5-dicarboxylic anhydride, and 2,7-octadien-1-ylsuccinic anhydride.

[0014] As the structural unit derived from a monomer having a dicarboxylic acid anhydride group, a structural unit derived from 5-norbornene-2,3-dicarboxylic acid anhydride is preferred in terms of industrial availability. The structural unit derived from the monomer having a dicarboxylic acid anhydride group may be of one type or of multiple types.

[0015] The dicarboxylic anhydride group may react with moisture in the air to open the ring and partially become a dicarboxylic acid, but the dicarboxylic anhydride group may be ring-opened as long as it does not deviate from the gist of the present invention.

[0016] (3) Structural unit (p) The polar ethylene copolymer (A) used in the present invention may be a binary copolymer consisting of only the structural unit (m) and the structural unit (n), or a multi-component copolymer containing the structural unit (m), the structural unit (n), and a structural unit (p) other than these. The monomer that provides the structural unit (p) may be any monomer that is not included in the monomers that provide the structural unit (m) and the structural unit (n), and is not limited as long as it is a compound having one or more carbon-carbon double bonds in its molecular structure.

[0017] Specific examples of acyclic monomers that provide the structural unit (p) include (meth)acrylic acid esters having an ester group having 2 to 20 carbon atoms. Specific examples include methyl (meth)acrylate, ethyl (meth)acrylate, n-propyl (meth)acrylate, isopropyl (meth)acrylate, n-butyl (meth)acrylate, isobutyl (meth)acrylate, t-butyl (meth)acrylate, pentyl (meth)acrylate, hexyl (meth)acrylate, cyclohexyl (meth)acrylate, octyl (meth)acrylate, 2-ethylhexyl (meth)acrylate, nonyl (meth)acrylate, decyl (meth)acrylate, dodecyl (meth)acrylate, octadecyl (meth)acrylate, phenyl (meth)acrylate, toluyl (meth)acrylate, and benzyl (meth)acrylate. Preferably, acrylic acid esters are used, and specific examples of the compound include at least one selected from the group consisting of methyl acrylate, ethyl acrylate, n-butyl acrylate (nBA), isobutyl acrylate (iBA), t-butyl acrylate (tBA), and 2-ethylhexyl acrylate, and particularly at least one selected from the group consisting of n-butyl acrylate (nBA) and isobutyl acrylate (iBA). Other examples of non-cyclic monomers include 5-hexen-1-ol, allyl methyl ether, ethyl-4-pentenoate, 4-chloro-1-butene, methyl vinyl ether, styrene, vinyltrimethylsilane, vinyl chloride, and (meth)acrylonitrile. The acyclic monomer may be of one type or of multiple types.

[0018] 2.2 Resin properties of polar ethylene copolymer (A) (1) Number of branches per 1,000 carbon atoms in the polymer In the polar ethylene copolymer (A) according to the present invention, in order to increase the elastic modulus and obtain sufficient mechanical properties, 13The number of methyl branches calculated by C-NMR per 1,000 carbon atoms may be an upper limit of 50, 5.0, 1.0, or 0.5, with no particular lower limit, and the lower limit is the better. The number of ethyl branches per 1,000 carbon atoms may be an upper limit of 3.0, 2.0, 1.0, or 0.5, with no particular lower limit, and the lower limit is the better. The number of butyl branches per 1,000 carbon atoms may be an upper limit of 7.0, 5.0, 3.0, or 0.5, with no particular lower limit, and the lower limit is the better.

[0019] (2) Method for measuring the amount of structural units derived from monomers having dicarboxylic acid anhydride groups and acyclic monomers in copolymers, and the number of branches The amount of structural units derived from the monomer having a dicarboxylic acid anhydride group and the acyclic monomer in the polar ethylene copolymer (A) of the present invention, and the number of branches per 1,000 carbon atoms can be determined using C-NMR spectroscopy. C-NMR is measured by the following method. 200-300 mg of sample is placed in an NMR sample tube with an inner diameter of 10 mm, together with 2.4 ml of a mixed solvent of o-dichlorobenzene (C6H4Cl2) and deuterated bromide benzene (C6D5Br) (C6H4Cl2 / C6D5Br = 2 / 1 (volume ratio)) and hexamethyldisiloxane, a chemical shift reference substance, and the tube is purged with nitrogen, then sealed and heated to dissolve into a homogeneous solution, which is used as the NMR measurement sample. NMR measurements are carried out at 120°C using an AV400M NMR instrument manufactured by Bruker Japan Ltd. equipped with a 10 mmφ cryoprobe. 13 C-NMR is measured using the inverse gate decoupling method with a sample temperature of 120°C, a pulse angle of 90°, a pulse interval of 51.5 seconds, and an accumulation count of 512 or more. The chemical shifts were set to 1.98 ppm for the 13C signal of hexamethyldisiloxane and 1.98 ppm for other 13The chemical shift of the C signal is based on this. obtained 13 In C-NMR, signals specific to the monomers or branches of a multicomponent copolymer can be identified and their intensities compared to analyze the amount of structural units of each monomer in the multicomponent copolymer and the number of branches. The positions of the signals specific to the monomers or branches can be determined by reference to publicly known materials or can be independently identified depending on the sample. Such analytical techniques are commonly known to those skilled in the art.

[0020] (4) Molecular structure of copolymer The molecular chain terminal of the copolymer according to the present invention may be a structural unit (m) derived from ethylene, a structural unit (n) derived from a monomer having a dicarboxylic acid anhydride group, or a structural unit (p) derived from an acyclic monomer.

[0021] (2) Polyethylene resin (C) The polyethylene resin composition (B) preferably further contains a polyethylene resin (C) having the following properties (c-1) to (c-7).

[0022] Property (c-1): Melt flow rate (MFR) The melt flow rate (MFR: 190°C, 21.18 N load) of the polyethylene resin (C) is 0.1 to 100 g / 10 min, preferably 1 to 80 g / 10 min, and more preferably 5 to 70 g / 10 min. An MFR of less than 0.1 g / 10 min is undesirable because it results in poor extensibility during molding and increases the motor load in the extruder. On the other hand, an MFR of more than 100 g / 10 min is undesirable because it results in an unstable state of the molten film during molding. The MFR of the polyethylene resin (C) can be adjusted, for example, by appropriately adjusting the polymerization temperature, the amount of comonomer, etc. Here, MFR is a value measured in accordance with JIS-K6922-2:1997 Appendix (190°C, 21.18N load).

[0023] Property (c-2): Total heat of fusion ΔHm The total heat of fusion ΔHm of the polyethylene resin (C) is 30 to 120 J / g, preferably 32 to 118 J / g, and more preferably 35 to 115 J / g. If ΔHm is less than 30 J / g, blocking will be poor, which is not preferred. On the other hand, if ΔHm exceeds 120 J / g, the adhesiveness becomes poor, which is undesirable. To adjust ΔHm of the polyethylene resin (C), for example, a method of appropriately adjusting the comonomer content, polymerization temperature, catalyst amount, etc. can be used. Here, ΔHm represents the heat of fusion in the melting curve measured by a differential scanning calorimeter (DSC). Generally, ethylene-based resins with low crystallinity tend to have a broader melting peak and a smaller ΔHm than ethylene-based resins with high crystallinity.

[0024] Characteristic (c-3): Crystallization temperature Tc The crystallization temperature Tc of the polyethylene resin (C) is 25 to 90°C, preferably 27 to 88°C, and more preferably 30 to 85°C. If Tc is less than 25°C, the crystallinity is too low, resulting in poor blocking, which is undesirable. On the other hand, if Tc is more than 90°C, the presence of highly crystalline components results in poor adhesion, which is undesirable. Here, Tc indicates the highest peak temperature among the crystallization peaks in the crystallization curve measured by a differential scanning calorimeter (DSC).

[0025] Property (c-4): Monomer composition of polyethylene resin (C) The polyethylene resin (C) is an ethylene-based copolymer characterized by containing 80 to 98 mol% of ethylene-derived structural units as a major component and 2 to 20 mol% of propylene-derived structural units as a minor component. A specific example is a copolymer obtained by polymerization using a catalytic polymerization method, which is a copolymer obtained by substantially linear random polymerization. A specific example is a random copolymer of ethylene and propylene. Preferably, the ethylene-derived structural units account for 82 to 97 mol% and the propylene-derived structural units for 3 to 18 mol%, more preferably 85 to 95 mol% and 5 to 15 mol%. Here, the amount of monomers such as the ethylene content is 13 The values ​​were measured and calculated by C-NMR under the conditions described in the Examples below.

[0026] Preferably, the polyethylene resin (C) is completely free of structural units derived from other α-olefins, particularly α-olefins having 4 to 20 carbon atoms, and other monomer components, but may contain such structural units in substantially trace amounts. In this specification, an α-olefin other than ethylene and propylene is referred to as a third α-olefin. The polyethylene resin (C) used in the present invention may contain structural units derived from a third α-olefin other than ethylene and propylene as a minor component, for example, in an amount of 5 mol% or less, preferably 2 mol% or less, more preferably 1.5 mol% or less, even more preferably 1 mol% or less, and most preferably 0.5 mol% or less. When the polyethylene resin (C) used in the present invention contains structural units derived from a third α-olefin, the total amount of the structural units derived from ethylene, propylene, and the third α-olefin does not exceed 100 mol%. In this case, the content of the structural units derived from propylene is preferably higher than the content of the structural units derived from the third α-olefin. Furthermore, when the polyethylene resin (C) used in the present invention contains structural units derived from a third α-olefin, one or more types of third α-olefins can be used.

[0027] When propylene is used as a secondary component and as an essential comonomer, and particularly when high-pressure ionic polymerization using a metallocene catalyst (described later) is employed, it is possible to obtain ethylene-α-olefin copolymers with a specifically high total number of vinyl and vinylidene units. On the other hand, when α-olefins such as 1-hexene and 1-octene are polymerized as the primary comonomer, this effect is difficult to achieve.

[0028] In addition, copolymers consisting of ethylene and propylene include so-called ethylene propylene rubber (EPM), which contains more than 20 mol% of propylene and has a density of 0.870 g / cm 3 Rubber-like polymers obtained by the following solution polymerization method are used in the field of elastomers, but the polyethylene resin (C) used in the present invention is a polymer that is completely different from these ethylene propylene rubbers in terms of density range, amount of ethylene and propylene contained therein, and physical properties. Furthermore, among propylene polymers, propylene-ethylene copolymers that contain a small amount of ethylene component during the production process are also known, but these are also polymers that are significantly different from the polyethylene resin (C) used in the present invention in terms of propylene content, etc., and also have completely different physical properties, etc.

[0029] Characteristic (c-5): Density The polyethylene resin (C) used in the present invention has a density of 0.88 to 0.94 g / cm 3 and preferably 0.885 to 0.94 g / cm 3 and more preferably 0.89 to 0.93 g / cm 3 The density is 0.88g / cm 3 On the other hand, if the density is less than 0.94 g / cm3, blocking will be poor, which is not preferable. 3 If it exceeds this value, the adhesiveness will be poor, which is not preferable. The density of the polymer can be adjusted by, for example, appropriately adjusting the comonomer content, polymerization temperature, catalyst amount, etc. The density of the ethylene copolymer is measured in accordance with JIS-K6922-2:1997 Appendix (for low-density polyethylene) (measurement temperature: 23°C).

[0030] Property (c-6): Total amount of vinyl and vinylidene The polyethylene resin (C) used in the present invention has a total number of vinyl and vinylidene double bonds per 1000 carbon atoms in the main chain and side chains measured by NMR of 0.35 (units / total 1000C) or more, preferably 0.40 to 5.0 (units / total 1000C), more preferably 0.45 to 4.5 (units / total 1000C), and even more preferably 0.50 to 4.0 (units / total 1000C). When the total amount of vinyl and vinylidene is within the above range, the laminate resin composition has excellent adhesive strength, but when it is less than 0.35, the adhesive strength is insufficient. The total amount of vinyl and vinylidene can be controlled within the above range by selecting an appropriate metallocene catalyst, adjusting the polymerization temperature, and the type of comonomer. The number of vinyl and vinylidene can also be adjusted by adjusting production conditions such as the type and amount of comonomer and the polymerization temperature. The number of double bonds is the number per 1000 carbon atoms in total in the main chain and side chains. 1 The values ​​were calculated using the integrated intensities of characteristic peaks in the H-NMR spectrum, and were measured and calculated under the conditions described in the Examples section below.

[0031] Furthermore, in the present invention, the number of vinyl groups in the polyethylene resin (C) preferably satisfies the range of 0.2 (groups / total 1000C) or more. In the present invention, the number of vinylidenes in the polyethylene resin (C) preferably satisfies the range of 0.12 (units / total 1000C) or more.

[0032] Property (c-7): Relationship between branch number (Y) and density (X) due to comonomer The polyethylene resin (C) used in the present invention preferably satisfies the requirements for the number of comonomer branches (Y) and density (X). Formula (1): (Y)≧-1157×(X)+1084 When the density and the number of branches are within the above ranges, the polyethylene resin composition has excellent tearability and adhesive strength.

[0033] The number of branches (Y) due to the comonomer indicates the amount of tertiary carbon contained in the polymer, and is the number per 1000 carbon atoms in total in the main chain and side chains, as measured by NMR. For example, see EW Hansen, R. Blom, and OM Bade, Polymer, Vol. 36, p. 4295 (1997). 13 It can be calculated from the C-NMR spectrum. The relationship between density and number of branches can be adjusted by the polymerization conditions such as the type and ratio of comonomers to be copolymerized and the polymerization temperature.

[0034] <Polymerization method for polyethylene resin (C)> The method for producing the polyethylene resin (C) used in the present invention that satisfies the requirements (c-1) to (c-7) is not particularly limited, and a high-pressure radical polymerization method, a high-pressure ionic polymerization method, a gas phase method, a solution method, a slurry method, etc. can be used.

[0035] The catalyst used in the production of the polyethylene resin (C) satisfying (c-1) to (c-7) is not particularly limited, but a metallocene catalyst is more preferably used. The metallocene catalyst is not particularly limited, but examples thereof include catalysts containing a metallocene compound such as a zirconium compound coordinated with a group having a cyclopentadienyl skeleton and a co-catalyst as catalytic components. In particular, it is preferable to use a metallocene compound such as a zirconium compound coordinated with a group having a cyclopentadienyl skeleton. The production method is not particularly limited, and a high-pressure ionic polymerization method, a gas phase method, a solution method, a slurry method, or the like can be used. However, in order to obtain the polyethylene resin (C) according to the present invention having adjusted double bonds, it is desirable to carry out the polymerization at a high temperature of 150 to 330°C, and therefore it is preferable to use a high-pressure ionic polymerization method ("Polyethylene Technology Reader," Chapter 4, edited by Kazuo Matsuura and Naotaka Mikami, 2001).

[0036] <Amount of polyethylene resin (C)> The content of the polyethylene resin (C) in the resin composition (B) is preferably 1 to 90% by weight, more preferably 5 to 50% by weight, or even more preferably 10 to 40% by weight.

[0037] (3) Polyethylene resin (D) The polyethylene resin composition (B) preferably further contains a polyethylene resin (D) having the following properties (d-1) to (d-2): The polyethylene resin (D) is preferably a low-density polyethylene.

[0038] Property (d-1): Melt flow rate (MFR) The melt flow rate (MFR) of the polyethylene resin (D) used in the present invention is 0.1 to 100 g / 10 min, preferably 0.5 to 50 g / 10 min, and more preferably 1 to 20 g / 10 min. If the MFR is less than 0.1 g / 10 min, the extensibility is insufficient, resulting in film breakage during high-speed molding. On the other hand, if the MFR exceeds 100 g / 10 min, the molten film becomes unstable. Here, the MFR is a value measured in accordance with JIS-K7210 (190°C, 21.18 N load).

[0039] Characteristic (d-2): Density The density of the polyethylene resin (D) used in the present invention is 0.91 to 0.97 g / cm 3 and preferably 0.915 to 0.96 g / cm 3 and more preferably 0.916 to 0.95 g / cm 3 The density is 0.91 g / cm 3 If it is less than 0.97g / cm, it will be sticky. 3 If it exceeds this value, the adhesiveness will be poor. Here, the density is measured (23° C.) in accordance with JIS-K6922-2:1997 Appendix (for low-density polyethylene).

[0040] The method for producing the polyethylene resin (D) used in the present invention is not particularly limited, and may be a high-pressure radical polymerization method, a high-pressure ionic polymerization method, a gas phase method, a solution method, a slurry method, etc. When producing low-density polyethylene, a tank reactor or a tubular reactor is generally used in the presence of a radical generator at a polymerization pressure of 1000 to 3000 kg / cm. 2 It is carried out by polymerizing ethylene at a polymerization temperature of 150 to 300°C. The MFR can be adjusted by using hydrogen or hydrocarbons such as methane and ethane as molecular weight regulators.

[0041] (5) Characteristics of polyethylene resin composition (B) (b-1) Melt flow rate (MFR) The melt flow rate (MFR: 190°C, 21.18 N load) of the polyethylene resin composition (B) used in the present invention is preferably 1 to 100 g / 10 min, more preferably 1 to 80 g / 10 min, and even more preferably 2 to 70 g / 10 min. An MFR of less than 1 g / 10 min is undesirable because the extensibility during molding deteriorates and the motor load in the extruder increases. On the other hand, an MFR of more than 100 g / 10 min is undesirable because the state of the molten film during molding becomes unstable. Here, MFR is a value measured in accordance with JIS-K6922-2:1997 Appendix (190°C, 21.18N load).

[0042] (b-2) Density The density of the polyethylene resin composition (B) used in the present invention is preferably 0.88 to 0.94 g / cm 3 and more preferably 0.885 to 0.94 g / cm 3 and more preferably 0.89 to 0.935 g / cm 3 The density is 0.88g / cm 3 On the other hand, if the density is less than 0.94 g / cm3, blocking will be poor, which is not preferable. 3 If it exceeds this value, the adhesiveness will be poor, which is not preferable.

[0043] (6) Other compounds The polyethylene resin composition (B) used in the present invention or the resin layer (ii) containing it may optionally contain additives commonly used in polyethylene resins, such as phenolic or phosphorus-based antioxidants, stabilizers such as metal soaps, antiblocking agents, lubricants, dispersants, organic or inorganic colorants or pigments, antifogging agents such as unsaturated fatty acid esters, antistatic agents, UV absorbers, light stabilizers, and nucleating agents. The amount of additive added is preferably 700 ppm or less, more preferably 400 ppm or less, even more preferably 200 ppm or less, and most preferably 100 ppm or less. Addition of too much additive is undesirable because it results in poor adhesion. Furthermore, other thermoplastic resins such as polyethylene resins such as LDPE, C4-LLDPE, HAO-LLDPE, ethylene-vinyl acetate copolymer (EVA), ethylene-acrylic acid ester copolymer (EEA, EMA, EMMA, etc.), high density polyethylene (HDPE), polypropylene resins, polystyrene resins, etc. may be blended into resin layer (B) as long as the properties of resin layer (B) are not impaired.

[0044] 2. Adhesive layer (c) The adhesive layer (iii) used in the present invention can be obtained by directly laminating an adhesive containing a reaction product of a polyol compound and a polyisocyanate compound onto the substrate layer 2 (iv) by known means such as coating or extrusion, and then curing the laminate. Such an adhesive is preferably a two-component curing polyurethane resin adhesive. By using an adhesive containing a reaction product of a polyol compound and a polyisocyanate compound as the adhesive layer (iii), both adhesion and tearability can be achieved. The resulting adhesive layer (c) contains a reaction product of a polyol compound and a polyisocyanate compound, and adhesives that have conventionally been used in extrusion coating methods and dry lamination methods can be used. The polyol is a polyol component having at least two hydroxyl groups in the molecule, such as polyurethane polyol, polyester polyol, polyether polyol, acrylic polyol, and laminating resin composition polyol, and these polyol components can be used alone or in combination of two or more.

[0045] Examples of isocyanate components having at least two isocyanate groups in the molecule include araliphatic diisocyanates, aliphatic diisocyanates, and alicyclic diisocyanates. Specific examples of araliphatic diisocyanates include 1,3- or 1,4-xylylene diisocyanate or a mixture thereof, 1,3- or 1,4-bis(1-isocyanato-1-methylethyl)benzene or a mixture thereof, and ω,ω'-diisocyanato-1,4-diethylbenzene. Specific examples of aliphatic diisocyanates include hexamethylene diisocyanate, tetramethylene diisocyanate, 2-methylpentane-1,5-diisocyanate, 3-methylpentane-1,5-diisocyanate, lysine diisocyanate, and trioxyethylene diisocyanate. Specific examples of alicyclic diisocyanates include isophorone diisocyanate, cyclohexyl diisocyanate, hydrogenated diphenylmethane diisocyanate, norbornane diisocyanate, hydrogenated tolylene diisocyanate, hydrogenated xylene diisocyanate, hydrogenated tetramethylxylene diisocyanate, etc. These isocyanate components can be used alone or in combination of two or more.

[0046] Specifically, adhesives (anchor coating agents) used in extrusion lamination processing, A-3210 / A-3070, A-3210 / A3072, A-3210 / A-3075 (manufactured by Mitsui Chemicals, Inc.), Seikadyne 2710A / Seikadyne 2810C(T), Seikadyne 2730A / Seikadyne 2730B, Seikadyne 2710A / Seikadyne 2710C (manufactured by Dainichiseika Color & Chemicals Mfg. Co., Ltd.), EL-510 / CAT-RT80, EL-530A / EL-530B, EL-540 / CAT-RT32 (manufactured by Toyo-Morton Co., Ltd.), T-120A / T-300 hardener, T- Adhesives used in dry lamination include DiC Dry LX-401A, 75A, 719, 703VL, 500, and 510 (manufactured by DIC Graphics), Takelac / Takenate A-909 / A-5, A-977 / A-92, A-606 / A-50, A-515 / A-50, A-626 / A-50, A-525 / A-52, and A-666 / A-65 (manufactured by Mitsui Chemicals), and RU-77, 771, 3600, and 3900 (manufactured by Rock Paint). In particular, it is preferable to use A-3210 / A-3070, A-3210 / A3072, A-3210 / A-3075 (manufactured by Mitsui Chemicals, Inc.), Seikadyne 2710A / Seikadyne 2810C(T), Seikadyne 2710A / Seikadyne 2710C (manufactured by Dainichiseika Color & Chemicals Mfg. Co., Ltd.), EL-510 / CAT-RT80, EL-540 / CAT-RT32 (manufactured by Toyo-Morton Co., Ltd.), etc.

[0047] 3. Base layer 1 (a), base layer 2 (d) The substrate layer 1(a) used in the present invention has an oxygen permeability of 1300 mL / m at 20°C and 65% RH. 2 ·day·MPa or less, preferably 400mL / m 2 By using this substrate for the substrate layer 1(a), a laminate having good protection performance for the contents can be obtained.

[0048] The type of substrate layer 1(a) is not particularly limited as long as it has the above-mentioned oxygen permeability characteristics, and examples include single-layer films or sheets of polyamide, polyester, polypropylene, polyethylene, ethylene-vinyl alcohol copolymer, polyvinylidene chloride, polycarbonate, etc., laminated films or laminated sheets made of the same or different materials, stretched products of the above-mentioned films or sheets, paper such as kraft paper, metal foil or metal plate such as aluminum, iron, copper, or alloys containing these as the main components, plastic film or sheet vapor-deposited with metal, inorganic material, or organic material, cellophane, woven fabric, nonwoven fabric, paper or plastic film with a barrier coating, etc., but metal foil or metal-deposited film is preferred. The use of a metal foil or metal-deposited film as the base layer 1(a) makes it easier to achieve the above oxygen permeability and is also preferable from the viewpoint of protecting the contents. The metal foil may be aluminum, iron, copper, or an alloy containing these as its main component.

[0049] The substrate layer 2(d) is a substrate containing an antistatic agent. The type of base layer 2(d) is not particularly limited as long as it contains an antistatic agent, and examples thereof include polypropylene (PP) film, polyester (PET) film, polyethylene (PE) film, and linear low-density polyethylene (LLDPE) film. The resin constituting the base layer 2(d) is often low in crystallinity. As the antistatic agent, known antistatic agents that have been conventionally used for preventing static electricity in OPP films and the like can be used. Examples of the antistatic agent include anionic antistatic agents such as adipic acid, glutamic acid, sulfonates, sulfate salts, phosphate salts, and phosphonate salts; cationic antistatic agents such as amines, imidazolines, amine oxide ethylene adducts, quaternary ammonium salts, and pyridinium salts; amphoteric antistatic agents having both a cationic group and an anionic group, such as guanidine salts obtained by reacting alkylamines with maleic anhydride, and sulfonic acids derived from polyethyleneimine; and nonionic antistatic agents such as polyols, ester compounds of polyols and aliphatic carboxylic acids, ether compounds, higher alcohol ethylene oxide adducts, alkylphenol ethylene oxide adducts, and fatty acid amides and their ethylene oxide adducts.

[0050] The base layer 1(a) and the base layer 2(d) may be of the same type or different types.

[0051] 4.Laminate The laminate of the present invention has at least four layers: a substrate layer 1 (a), a resin layer (b), an adhesive layer (c), and a substrate layer 2 (d), and the substrate layer 1 (a), the resin layer (b), the adhesive layer (c), and the substrate layer 2 (d) are laminated adjacent to each other. The laminate of the present invention may have further layers as long as it has the above-described configuration, for example, a different resin layer and / or a different substrate layer may be present outside the substrate layer 1 (a) and / or the substrate layer 2 (d). Here, examples of different resin layers include polyethylene-based resins such as LDPE, C4-LLDPE, HAO-LLDPE, ethylene-vinyl acetate copolymer (EVA), ethylene-acrylic acid copolymer (EAA), ethylene-methacrylic acid copolymer (EMAA), ethylene-acrylic acid ester copolymer (EEA, EMA, EMMA, etc.), high-density polyethylene (HDPE), adhesive resins such as ethylene-maleic anhydride copolymer, polypropylene-based resins, polystyrene resins, and other thermoplastic resins. Examples of different substrate layers include single-layer films or sheets of polyamide, polyester, polypropylene, polyethylene, ethylene-vinyl alcohol copolymer, polyvinylidene chloride, polycarbonate, etc.; laminated films or sheets made of the same or different materials; stretched versions of the above films or sheets; paper such as kraft paper; metal foils or metal plates such as aluminum, iron, copper, and alloys containing these as their main components; plastic films or sheets vapor-deposited with metals, inorganic materials, or organic materials; cellophane, woven fabric, nonwoven fabric, and paper or plastic films with barrier coatings.

[0052] The method for producing the laminate is not particularly limited, but a preferred method is, for example, the so-called extrusion coating method in which a polyethylene resin composition is melt-extruded and laminated onto a substrate layer. The extrusion coating is preferably performed by laminating one or more layers by a method such as single layer, sandwich lamination, coextrusion lamination, or tandem lamination. According to the present invention, high-speed molding is possible due to good adhesion to the substrate.

[0053] The method for ensuring adhesion between the base layer 1(A) and the resin layer (B) is not particularly limited, but for example, the surface of the base layer 1(A) can be subjected to a surface treatment, including anchor coating if necessary. Examples of surface treatment methods include corona discharge treatment, ozone treatment, flame treatment, and low-temperature plasma treatment. Another example is spraying ozone onto molten resin.

[0054] One embodiment of the method for producing a laminate of the present invention is a method for producing a laminate having at least four layers, namely, base material layer 1 (A), resin layer (B), adhesive layer (C), and base material layer 2 (D), by using an extrusion lamination molding machine, unwinding base material layer 2 (D) from a winding machine, extruding polyethylene resin composition (B) to form resin layer (B) to a predetermined thickness, unwinding base material layer 1 (A) from the sand side, and forming adhesive layer (C) on the surface of base material layer 2 (D) on the resin layer (B) side, and performing extrusion sand lamination. Here, the polyethylene resin composition (B) contains an ethylene copolymer (A), and preferably contains a polyethylene resin (C) and a polyethylene resin (D).

[0055] The laminate of the present invention contains a resin layer (ii) containing a polyethylene resin composition (B) and an adhesive layer (iii) containing a specific compound, and has excellent adhesive strength to substrates, etc., as well as good handling properties such as easy tearing properties, making it a laminate that is excellent in both content protection performance and easy opening and handling properties.

[0056] The laminate of the present invention has excellent adhesive strength to substrates and also excellent tearability, and therefore can be suitably used particularly as an easily tearable film for packaging bags, a film for packaging food, or a packaging material. That is, another aspect of the present invention is a packaging material comprising the laminate of the present invention.

[0057] Examples of packaging materials include, but are not limited to, paper containers for liquids, containers for packaging frozen desserts such as yokan and jelly, dried foods, oils and fats, confectionery, paper ties, paper cups, paper trays, etc. [Example]

[0058] The present invention will be described in detail below with reference to examples, but is not limited thereto. The measurement methods, resins, and adhesives used in the examples and comparative examples are as follows:

[0059] 1. Evaluation method for resin properties (1) Melt flow rate (MFR) The MFR of the polyethylene resin (C) and the polyethylene resin (D) was measured in accordance with JIS-K6922-2:1997 Appendix (190°C, 21.18 N load). (2) Density The densities of the polyethylene resin (C) and the polyethylene resin (D) were measured in accordance with JIS-K6922-2:1997 Appendix (23°C, in the case of low-density polyethylene).

[0060] (3) Total heat of fusion ΔHm, crystallization temperature Tc The total heat of fusion ΔHm and crystallization temperature Tc of polyethylene resin (C) were measured in accordance with the method of JIS K7121-1987. The pellets were hot-pressed into a sheet, which was then punched out to form a measurement sample. Measurement was carried out under the following conditions, with a first heating, a temperature drop, and a second heating. The temperature at the maximum peak height during the temperature drop was taken as Tc, and the heat of fusion on the melting curve during the second heating was taken as ΔHm. Equipment: SII Nanotechnology Inc. DSC7020 <Temperature rise and fall conditions> First temperature rise: 30℃ to 200℃ at 10℃ / min Temperature drop: 200°C to -30°C at 10°C / min Second temperature rise: -30℃ to 200℃ at 10℃ / min Temperature holding time: 5 minutes after first temperature rise, 5 minutes after temperature drop Sample size: 5mg Temperature calibration: Indium Reference: Aluminum

[0061] (4) Amount of comonomer, number of branches and double bonds due to comonomer The amount of comonomer and the number of branches due to comonomer (Y) are 13 By C-NMR, the number of double bonds (vinyl, vinylidene) is 1 Measurement was carried out by H-NMR under the following conditions, and the number was calculated per 1000 carbon atoms in total in the main chain and side chains. Apparatus: Bruker Biospin AVANCE III cryo-400MHz Solvent: o-Dichlorobenzene / bromobromobenzene = 8 / 2 mixed solution <Sample amount> Sample 460 mg / solvent 2.3 ml < 13 C-NMR · 1 H decoupling, NOE available Number of scans: 256 Flip angle: 90° Pulse interval: 20 seconds AQ (acquisition time) = 5.45 seconds D1 (waiting time) = 14.55 seconds < 1 H-NMR Accumulation count: 1400 scans Flip angle: 1.03° AQ (acquisition time) = 1.8 s D1 (waiting time) = 0.01 s

[0062] (5) Adhesive strength The obtained laminate was cut into 15 mm wide strips in the machine direction, and the base layer 1 (A) and the resin layer (B) were peeled at the interface between them. The number of specimens was 5, and the peel strength in a T-peel test at a peel speed of 300 mm / min was recorded as the adhesive strength. If the resin layer (B) broke while being pulled and peeled off from the base layer 1 (A), the numerical value at the highest point on the chart was recorded as the adhesive strength.

[0063] (6) Heat seal strength Two sheets of the resulting laminate were stacked, and heat-sealed with the lower seal bar at 30°C and the upper seal bar at 140°C, a sealing pressure of 0.2 MPa, and a sealing time of 1.0 second, and the 180° peel strength of a 15 mm width was measured. The heat-sealability was evaluated based on the obtained heat-seal strength value according to the following criteria. ○: Heat seal strength is 10N / 15mm width or more. ×: Heat seal strength is less than 10N / 15mm width.

[0064] 2.Material (1) Polar ethylene copolymer (A) (PE-1) obtained by the following production method was used as the polar ethylene copolymer (A). Its physical properties are shown in Table 1. (The MFR measured in accordance with JIS-K6922-2:1997 Appendix (190°C, 21.18 N load) was 9.0 g / 10 min, n (maleic anhydride content in the copolymer) measured by the method described in JP-A No. 2023-142138 was 1.5 wt%, and the weight ratio of ethylene-maleic anhydride (MAh)-methyl acrylate (MA) copolymer is as shown in Table 1.) (2) Polyethylene resin (C) (PE-2) obtained by the following production method was used as the polyethylene resin (C). The physical property values are shown in Table 1.

[0065] <Production method of PE-1> As the polar ethylene-based copolymer (A), an ethylene-methyl acrylate-maleic anhydride terpolymer was used. This terpolymer was produced by copolymerizing three kinds of monomers using the equipment of a low-density polyethylene plant under the conditions of a polymerization temperature of 195 °C and a polymerization pressure of 188 MPa with tert-butyl peroxyneodecanoate as an initiator. <Production method of PE-2> (i) Preparation of catalyst To 0.05 mol of the complex "rac-dimethylsilylenebisindenylhafnium dimethyl" prepared by the method described in JP-A-10-218921, an equimolar amount of "N,N-dimethylanilinium tetrakis(pentafluorophenyl)borate" was added and diluted to 50 liters with toluene to prepare a catalyst solution.

[0066] (ii) Polymerization method Using a stirred autoclave type continuous reactor with an internal volume of 5.0 liters, while maintaining the pressure in the reactor at 80 MPa and appropriately adjusting ethylene and propylene, the raw material gas was continuously supplied at a rate of 40 kg / h. Further, the catalyst solution described in the section "(i) Preparation of catalyst" was continuously supplied, and the polyethylene resin (C) was obtained by appropriately adjusting the polymerization temperature within the range of 150 to 250 °C.

[0067] (3) Polyethylene resin (D) The polyethylene resin (PE-3) having the physical property values shown in Table 1 was used.

[0068] (4) Adhesive layer (ha) As the adhesive layer (ha), (AC-1) described below was used. (AC-1) A mixture of Seikadyne 2710A, Seikadyne 2810C(T), and ethyl acetate manufactured by Dainichiseika Color & Chemicals Mfg. Co., Ltd. in a ratio of 1:2:15.6 (solid content concentration: 7 wt%, containing a reaction product of a polyol compound and a polyisocyanate compound) was used.

[0069] (5) Base layer 1 (a) An aluminum foil (thickness 7 μm, oxygen permeability approximately 0 mL / m 2 ·day·MPa at 20° C. and 65% RH) manufactured by Toyo Aluminum Co., Ltd. was used. Hereinafter, this will be referred to as (substrate layer 1-1).

[0070] (6) Base layer 2 (D) As the base layer 2(d), the following (base layer 2-1) to (base layer 2-3) were used. Base layer 2-1: OPP film FOR (thickness 20 μm) containing an antistatic agent manufactured by Futamura Chemical Co., Ltd. was used. Substrate layer 2-2: The printing substrate for substrate layer 2-1 (printing ink: Rio Alpha R631 white, manufactured by Toyo Ink Co., Ltd.) was used. Substrate layer 2-3: The printing substrate of the substrate layer 2-1 (printing ink: Rio Alpha R631 White manufactured by Toyo Ink Co., Ltd. and a curing agent (SP curing agent 2KC, blended at 3% by weight)) was used.

[0071] Example 1 20% by weight of polar ethylene copolymer (A) (PE-1), 16% by weight of polyethylene resin (C) (PE-2), and 64% by weight of polyethylene resin (D) (PE-3) were blended and thoroughly mixed, followed by use of a 40 mmφ single-screw extruder to obtain pellets of polyethylene resin composition (B). Using an extrusion lamination molding machine, a 500 mm wide (substrate layer 2-2) was fed from the feeder as substrate layer 2 (d), and the pellets obtained above were adjusted to a take-up speed of 100 m / min and a coating thickness of 15 μm. Substrate layer 1-1 was fed from the sand side as substrate layer 1 (a), and extrusion sand lamination was performed. Next, anchor coating treatment was performed on the opposite side of substrate layer 1 (a) to the resin layer (b) side using (AC-1) as adhesive layer (c), and LDPE (Novatec LC600A manufactured by Japan Polyethylene Co., Ltd.) was extrusion laminated at a take-up speed of 100 m / min and a coating thickness of 20 μm to obtain a laminate of substrate layer 2 (d), resin layer (b), substrate layer 1 (a), and LC600A layer. The extrusion lamination molding machine was set so that the temperature of the resin extruded from a T-die attached to a 90mm diameter extruder was 320°C, and the extrusion rate was adjusted so that the coating thickness would be the specified value when the cooling roll surface temperature was 20°C, the die width was 560mm, and the take-up speed was 100m / min. The resulting laminate was then evaluated for adhesive strength and heat seal strength as described above. The evaluation results are shown in Table 1.

[0072] Example 2 A laminate was produced in the same manner as in Example 1, except that base layer 2-2 was used instead of base layer 2(d) in Example 1. The evaluation results are shown in Table 1.

[0073] (Comparative Example 1) A laminate was produced in the same manner as in Example 1, except that 100% by weight of polyethylene resin (D) (PE-3) was used, base layer 2 (d) was (base layer 2-1), and the temperature of the resin extruded from the T-die of the extrusion lamination molding machine was set to 312° C. The evaluation results are shown in Table 1.

[0074] (Comparative Example 2) A laminate was produced in the same manner as in Comparative Example 1, except that base layer 2-2 was used instead of base layer 2(d) in Comparative Example 1. The evaluation results are shown in Table 1.

[0075] (Comparative Example 3) A laminate was produced in the same manner as in Comparative Example 1, except that 20% by weight of polyethylene resin (C) (PE-2) and 80% by weight of polyethylene resin (D) (PE-3) were used. The evaluation results are shown in Table 1.

[0076] Comparative Example 4 A laminate was produced in the same manner as in Comparative Example 3, except that base layer 2-2 was used instead of base layer 2(d) in Comparative Example 3. The evaluation results are shown in Table 1.

[0077] [Table 1]

[0078] (Results of Examples and Comparative Examples) Comparing the above Examples 1 and 2 with Comparative Examples 1 to 4, it can be seen that the laminates using the polar ethylene copolymer of the present invention are laminates that have excellent adhesive strength between the base layer 1 (A) and the resin layer (B) as well as excellent heat-sealing strength. In particular, the adhesive strength does not decrease even after long-term storage at high temperatures. Furthermore, it can be seen that the presence or absence of a curing agent in the printing substrate does not have an effect on the laminates in Examples 1 and 2, and that the laminates have excellent adhesive strength between the base layer 1 (A) and the resin layer (B) as well as excellent heat-sealing strength. On the other hand, a comparison of the results of Comparative Example 1 with Comparative Example 2 reveals that the adhesive strength and heat seal strength of the product stored at 23°C and 50% relative humidity for one week in Comparative Example 2 are good, but that the adhesive strength and heat seal strength decrease after one week storage at 40°C and 90% relative humidity. Also, a comparison of the results of Comparative Example 3 with Comparative Example 4 reveals that the adhesive strength and heat seal strength of the product stored at 23°C and 50% relative humidity for one month are good, but that the adhesive strength and heat seal strength decrease after one month storage at 40°C and 90% relative humidity.

Claims

1. The film has at least four layers: a base layer 1 (a), a resin layer (b), an adhesive layer (c), and a base layer 2 (d), A laminate comprising a substrate layer 1 (a), a resin layer (b), an adhesive layer (c), and a substrate layer 2 (d) laminated adjacent to each other, each of which satisfies the following properties: Base layer 1 (a): Oxygen permeability is 1300 mL / m at 20°C and 65% RH ２ ·day·MPa or less. Resin layer (ii): Contains a polyethylene resin composition (B) containing a dicarboxylic anhydride group-containing polar ethylene copolymer (A) having the following characteristic (a): (a) Contains, as essential structural units, a structural unit (m) derived from ethylene and a structural unit (n) derived from a monomer having a dicarboxylic acid anhydride group, and contains, as an essential secondary component, 0.5% by weight or more of the structural unit (n) derived from a monomer having a dicarboxylic acid anhydride group. Adhesive layer (c): Contains a reaction product of a polyol compound and a polyisocyanate compound. Substrate layer 2 (d): a substrate containing an antistatic agent

2. The laminate according to claim 1, wherein the polyethylene resin composition (B) further contains a polyethylene resin (C) having the following properties (c-1) to (c-7): (c-1) MFR (190°C, 21.18 N load) of 0.1 to 100 g / 10 min (c-2) In DSC, the total heat of fusion ΔHm is 30 to 120 J / g. (c-3) Crystallization temperature Tc is 25 to 90°C (c-4) Contains 80 to 98 mol% of structural units derived from ethylene as a major component, 2 to 20 mol% of structural units derived from propylene as an essential minor component, and may contain 5 mol% or less of structural units derived from a third α-olefin other than ethylene and propylene as a minor component. (However, when the structural units derived from the third α-olefin are contained, the total of the structural units derived from ethylene, the structural units derived from propylene, and the structural units derived from the third α-olefin does not exceed 100 mol %). (c-5) Density is 0.88 to 0.94 g / cm ３ (c-6) The total amount of vinyl and vinylidene in polyethylene resin (C) is 0.35 (pieces / total 1000C) or more (Note that the number of vinyl and vinylidene groups is the number per 1,000 carbon atoms in total in the main chain and side chains as measured by NMR.) (c-7) The number of branches (Y) due to comonomers in the polyethylene resin (C) and the density (X) satisfy the relationship of the following formula (1). Formula (1): (Y)≧−1157×(X)+1084 (where Y is the number per 1,000 carbon atoms in total in the main chain and side chains as measured by NMR.)

3. The laminate according to claim 1 or 2, wherein the polyethylene resin composition (B) further contains a polyethylene resin (D) having the following properties (d-1) to (d-2): (d-1) MFR (190°C, 21.18N load) of 0.1 to 100g / 10min (d-2) Density is 0.91 to 0.97 g / cm ３

4. The laminate according to claim 1 or 2, wherein the polar ethylene copolymer (A) is a polar group-containing ethylene copolymer of ethylene and an α,β-unsaturated carboxylic acid anhydride produced using a high-pressure radical polymerization process.

5. 3. The laminate according to claim 1, wherein the substrate layer 1(a) is a metal foil or a metal-deposited film.

6. 3. The laminate according to claim 1, wherein the laminate is formed by an extrusion coating method.

7. A packaging material comprising the laminate according to claim 1 or 2.

Images