Laminate for thermal lamination

Abstract

To provide a film for heat lamination which is excellent in moldability and low temperature heat sealability.SOLUTION: There is provided a laminate for heat lamination in which a resin layer (A) is laminated on a base material layer (B). Resin layer: containing an ethylene-propylene copolymer having (c-1) to (c-5). (c-1): The polyethylene resin composition contains 80-98 mol% of ethylene as a main component and 2-20 mol% of propylene as a necessary auxiliary component, and may contain 7 mol% or less of third α-olefin as an auxiliary component, (c-2): MFR of 1-100 g / 10 minutes, (c-3): density of 0.88-0.94 / cm3, (c-4): total content of vinyl and vinylidene in the ethylene-propylene copolymer of 0.35 (piece / total 1,000 C) or more, and (c-5): the number (Y) of branches and density (X) satisfy Expression (1): (Y)≥-1360×(X)+1270. Base material layer: containing paper, a polypropylene resin, a polyester resin or a polyamide resin as a main component.SELECTED DRAWING: None

Description

Technical Field

[0001] The present invention relates to a laminate for thermal lamination and a thermal lamination product, and more particularly to a laminate for thermal lamination and a thermal lamination product having excellent extrusion lamination processability and low-temperature sealability.

Background Art

[0002] In order to protect the printed surface of flexible packaging materials such as printed pulp paper and synthetic paper, impart water resistance, oil resistance, and luster for beautification, it is usually carried out to laminate a film on a printed matter. The film is generally referred to as a laminate for thermal lamination. Products in which a laminate for thermal lamination is laminated on the printed surface are applied to covers of books, magazines, stationery such as files, paper packages, flexible packaging materials, and the like. In addition, in products in which a resin layer is laminated on a base material layer such as paper, such as paper bundles, paper cups, and paper trays, a part of them is overlapped, for example, in a cylindrical shape, and in the overlapped part, the resin layer on one surface and the base material layer on the other back surface are thermally laminated (thermocompression bonded).

[0003] Conventionally, as a film for thermal lamination, a laminate obtained by laminating a mixture of an ethylene-α-olefin copolymer produced using a metallocene catalyst and low-density polyethylene on a base material by an extrusion lamination process has been used (see Patent Documents 1 and 2).

[0004] Patent Documents 1 and 2 describe a laminated film provided with a resin adhesive layer containing the following components (A) and (B) having a melting point lower than the melting point of the thermoplastic resin of the base material on one side of the thermoplastic resin film resin. (A) 60 to 97% by weight of a linear ethylene copolymer having a specific density and MFR obtained by copolymerizing ethylene and an α-olefin having 3 to 12 carbon atoms using a metallocene compound as a catalyst, (B) 40 to 3% by weight of an ethylene resin having a specific density and MFR. Also described is a thermal lamination product obtained by thermal lamination, that is, thermocompression bonding, using the laminated film so that the resin adhesive layer is bonded to the paper base material.

[0005] Conventional films for thermal lamination as described above have good extrusion lamination processability and adhesiveness to substrates typified by paper. However, there is a problem in the temperature range during thermal lamination. In particular, when performing thermal lamination at low temperatures, the adhesiveness to the substrate deteriorates. When the density of the ethylene-α-olefin copolymer is lowered to improve the thermal lamination property at low temperatures, there is a problem that the thermal lamination product wound up after extrusion lamination is likely to block when being wound up.

Prior Art Documents

Patent Documents

[0006]

Patent Document 1

Patent Document 2

Summary of the Invention

Problems to be Solved by the Invention

[0007] An object of the present invention is to provide a laminate having excellent adhesiveness to a substrate in a wide temperature range when performing thermal lamination in view of the above problems.

Means for Solving the Problems

[0008] As a result of intensive studies to solve the above problems, the present inventors have newly prototyped an ethylene-propylene copolymer having physical properties of the following new regions (c-1) to (c-5), and an ethylene-propylene copolymer having such specific properties, that is, a main component of ethylene and a sub-component of propylene in a predetermined amount, with a density and MFR within a certain range, a large amount of double bonds contained in the copolymer, and a large number of branches. Using a polyethylene resin composition containing an ethylene-propylene copolymer and preferably further containing a specific high-pressure radical polymerization method low-density polyethylene, a thermal laminate having a resin layer directly formed on a base material layer has excellent thermal laminate adhesiveness to a printed matter that is a thermal lamination target or a base material mainly composed of paper, polypropylene resin, polyethylene terephthalate resin, or nylon resin, and thus the present invention has been completed.

[0009] That is, according to the first invention of the present invention, it has at least two layers of a resin layer (A) and a base material layer (B), The resin layer (A) is formed by laminating directly on the base material layer (B) or on another resin layer laminated on the base material layer and is located on the outermost layer, and a thermal laminate is provided in which the resin layer (A) and the base material layer (B) satisfy the following characteristics respectively. Resin layer (A): containing a polyethylene resin composition (F) containing an ethylene-propylene copolymer (C) having the following characteristics (c-1) to (c-5) (c-1) Containing 80 to 98 mol% of structural units derived from ethylene as the main component, 2 to 20 mol% of structural units derived from propylene as an essential sub-component, and optionally containing up to 7 mol% of structural units derived from a third α-olefin other than ethylene and propylene (However, when containing structural units derived from the third α-olefin, 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-2) MFR (190 ° C, 21.18 N load) is 1 to 100 g / 10 min (c-3) The density is 0.88 to 0.94 g / cm 3 (c-4) The total amount of vinyl and vinylidene in the ethylene-propylene copolymer is 0.35 (per 1000C in total) or more (However, the number of vinyl and vinylidene is the number per 1000 carbon atoms in the main chain and side chain measured by NMR.) (c-5) The number of branches (Y) due to the comonomer and the density (X) in the ethylene-propylene copolymer satisfy the following formula (1). Formula (1): (Y) ≧ -1360×(X) + 1270 (However, Y is the number per 1000 carbon atoms in the main chain and side chain measured by NMR.) Base material layer (B): A base material mainly composed of paper, polypropylene resin, polyester resin, or polyamide resin

[0010] Also, according to the second invention of the present invention, in the first invention, the polyethylene resin composition (E) contains a high-pressure radical polymerization method low-density polyethylene (D) having the following characteristics (d-1) to (d-2), and a thermal lamination laminate is provided. (d-1) MFR (190 °C, 21.18 N load) is 0.1 to 20 g / 10 min (d-2) The density is 0.915 to 0.930 g / cm 3

[0011] Also, according to the third invention of the present invention, in the first or second invention, the content of the ethylene-propylene copolymer (C) contained in the polyethylene resin composition (F) is 99 to 1% by weight and the high-pressure radical polymerization method low-density polyethylene (D) is 1 to 99% by weight, and a thermal lamination laminate is provided, which may contain an ethylene-α-olefin copolymer (E). (However, when the ethylene-α-olefin copolymer (E) is included, the total of the ethylene-propylene copolymer (C) and the high-pressure radical polymerization method low-density polyethylene (D) does not exceed 100% by weight)

[0012] Further, according to a fourth invention of the present invention, in any one of the first to third inventions, there is provided a laminate for thermal lamination, characterized in that the polyethylene resin composition (F) further satisfies the following characteristics (f-1) to (f-2). (f-1) The MFR is 1 to 100 g / 10 min (f-2) The density is 0.88 to 0.94 g / cm 3

[0013] Further, according to a fifth invention of the present invention, in any one of the first to fourth inventions, there is provided a laminate for thermal lamination, characterized in that the polyethylene resin composition (F) further has the following characteristics (f-1) to (f-2). (f-1) The MFR is 5 to 60 g / 10 min (f-2) The density is 0.88 to 0.92 g / cm 3

[0014] Further, according to a sixth invention of the present invention, in any one of the first to fifth inventions, there is provided a laminate for thermal lamination, characterized in that the base material layer (B) is paper, or a stretched polypropylene film, or a stretched polyethylene terephthalate film, or a stretched nylon film.

[0015] Further, according to a seventh invention of the present invention, in any one of the first to sixth inventions, there is provided a laminate for thermal lamination, characterized in that the resin layer (A) is formed on the base material layer (B) by an extrusion coating method.

Advantages of the Invention

[0016] The laminate for thermal lamination of the present invention exhibits good thermal lamination adhesiveness with thermal lamination objects such as printed matter, and paper substrates, polypropylene resin films, polyethylene terephthalate resin films, nylon resin films, etc., which are its own base material layers.

Brief Description of the Drawings

[0017]

Figure 1

Figure 2

Figure 3

Explanation of Reference Numerals

[0018] 1 Base material layer (B) 2 Resin layer (A)

Embodiments for Carrying Out the Invention

[0019] The present invention relates to a laminate for thermal lamination, comprising a resin layer containing a polyethylene resin composition containing a specific ethylene-propylene copolymer and preferably a specific high-pressure radical polymerization method low-density polyethylene, and a base material layer in which at least the surface in contact with the resin layer is paper, or a film mainly composed of polypropylene resin, polyethylene terephthalate resin, or nylon resin and essential. Hereinafter, each component used in the present invention and the laminate for thermal lamination using the same will be described in detail.

[0020] 1. Polyethylene resin composition (F) The polyethylene resin composition of the present invention (hereinafter, also simply referred to as the resin composition) is characterized by containing an ethylene-propylene copolymer (C), and preferably further contains a high-pressure radical polymerization method low-density polyethylene (D), and more preferably contains 99 to 1% by weight of the ethylene-propylene copolymer (C) and 1 to 99% by weight of the high-pressure radical polymerization method low-density polyethylene (D). Further, in addition to the ethylene-propylene copolymer (C) and the high-pressure radical polymerization method low-density polyethylene (D), an ethylene-α-olefin copolymer (E) may be contained.

[0021] (1) Ethylene-propylene copolymer (C) The ethylene-propylene copolymer (C) used in the present invention has the following characteristics (c-1) to (c-5). (c-1) It contains 80 to 98 mol% of structural units derived from ethylene as the main component, 2 to 20 mol% of structural units derived from propylene as an essential sub-component, and may contain 7 mol% or less of structural units derived from a third α-olefin other than ethylene and propylene as a sub-component (However, when it contains structural units derived from the above third α-olefin, 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-2) MFR (190 °C, 21.18 N load) is 1 to 100 g / 10 min (c-3) Density is 0.88 to 0.94 g / cm 3 (c-4) The total amount of vinyl and vinylidene in the ethylene-propylene copolymer is 0.35 (pieces / total 1000C) or more (However, the number of vinyl and vinylidene is the number per 1000 carbon atoms in the total of the main chain and side chain measured by NMR.) (c-5) The number of branches (Y) due to the comonomer in the ethylene-propylene copolymer and the density (X) satisfy the relationship of the following formula (1). Formula (1): (Y) ≥ -1360×(X) + 1270 (However, Y is the number per 1000 carbon atoms in the total of the main chain and side chain measured by NMR.)

[0022] In addition, as a copolymer composed of ethylene and propylene, there is so-called ethylene-propylene rubber (EPM), which contains more than 20 mol% of propylene component and has a density of 0.870 g / cm 3 The rubber-like polymer obtained by the following solution polymerization method is used in the field of elastomers. However, the ethylene-propylene copolymer (C) of the present invention is a polymer with a different density range, different amounts of ethylene and propylene contained, and completely different physical properties from these ethylene-propylene rubbers. In addition, in propylene polymers, propylene-ethylene copolymers containing a small amount of ethylene component in the production process are also known. However, these are also significantly different from the ethylene-propylene copolymer (C) of the present invention in terms of their propylene content and the like, and are polymers with completely different physical properties and the like. In addition, since ethylene-α-olefin copolymers (e.g., LLDPE) having a so-called normal linear molecular structure are mainly developed for film applications, usually, C4 or higher α-olefins such as C4 and C6 are used as the main comonomer components to obtain a high-strength copolymer. It is a copolymer composed of ethylene and propylene using a C3 comonomer, which results in low strength, as the main secondary component, and has a density of 0.88 g / cm 3 The above copolymers have hardly been noticed so far and have not been commercially available at least from the applicant. Now, newly, an ethylene-propylene copolymer was prototyped using a C3 comonomer as the main secondary component in such a density range and various studies were conducted. As a result, it was found that the effects of the present invention can be obtained in a laminate containing a polyethylene resin composition using an ethylene-propylene copolymer having physical properties in a new region, particularly (c-1) to (c-5).

[0023] (i) Characteristics of ethylene-propylene copolymer (C) (c-1) Monomer composition The ethylene-propylene copolymer (C) used in the present invention is an ethylene-propylene copolymer characterized by containing 80 to 98 mol% of structural units derived from ethylene as the main component and 2 to 20 mol% of structural units derived from propylene as the sub-component. As a specific example, it is a copolymer obtained by polymerization by the catalyst polymerization method, and is a copolymer formed by substantially linear and random polymerization. As a specific example, it is a random copolymer of ethylene and propylene. Preferably, the structural units derived from ethylene are 82 to 97 mol%, the structural units derived from propylene are 3 to 18 mol%, more preferably the structural units derived from ethylene are 85 to 95 mol%, and the structural units derived from propylene are 5 to 15 mol%. Here, the monomer amounts such as the ethylene content are values measured and calculated under the conditions described in the examples below by 13C-NMR.

[0024] In addition, a structure containing no structural units derived from other α-olefins, particularly α-olefins having 4 to 20 carbon atoms, and other monomer components is preferable, but a structure containing such components in substantially trace amounts may also be included. In this specification, α-olefins other than ethylene and propylene are referred to as the third α-olefin. The ethylene-propylene copolymer (C) of the present invention may contain, as a sub-component, structural units derived from a third α-olefin other than ethylene and propylene, for example, 7 mol% or less, preferably 5 mol% or less, more preferably 2 mol% or less, particularly preferably 1.5 mol% or less, still more preferably 1 mol% or less, and most preferably 0.5 mol% or less. Here, when the ethylene-propylene copolymer (C) of the present invention contains structural units derived from a third α-olefin, 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%. Preferably, the total is 100 mol%. Also, 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. Further, when the ethylene-propylene copolymer (C) of the present invention contains structural units derived from a third α-olefin, one or more third α-olefins can be used. In addition, the ethylene-propylene copolymer (C) may be one kind or a combination of two or more kinds within the range satisfying (c-1) to (c-5).

[0025] When propylene is used as an essential comonomer with a minor component, particularly when the high-pressure ionic polymerization method using a metallocene catalyst described later is adopted, it becomes possible to specifically obtain an ethylene-α-olefin copolymer having a large total number of vinyl and vinylidene. When polymerizing with α-olefins such as 1-hexene and 1-octene as the main component of the comonomer, this effect is difficult to obtain.

[0026] (c-2) MFR The ethylene-propylene copolymer (C) used in the present invention has a melt flow rate (MFR: 190 ° C, 21.18 N load) of 1 to 100 g / 10 min, preferably 1 to 80 g / 10 min, more preferably exceeding 5 g / 10 min and 60 g / 10 min or less. If the MFR is less than 1 g / 10 min, the ductility during laminate molding deteriorates and the motor load in the extruder increases, which is not preferable. On the other hand, if the MFR exceeds 100 g / 10 min, the state of the molten film during molding becomes unstable, which is not preferable. To adjust the MFR of the polymer, for example, a method of appropriately adjusting the polymerization temperature, the amount of comonomer, etc. is adopted. The MFR of the ethylene-propylene copolymer is measured in accordance with JIS-K6922-2:1997 Annex (190 ° C, 21.18 N load).

[0027] (c-3) Density The ethylene-propylene copolymer (C) used in the present invention has a density of 0.88 to 0.94 g / cm 3 and preferably 0.88 to 0.93 g / cm 3 and more preferably 0.88 to 0.92 g / cm 3 . If the density is less than 0.88 g / cm 3 , blocking becomes poor, which is not preferable. On the other hand, if the density exceeds 0.94 g / cm 3 , the adhesiveness becomes poor, which is not preferable. To adjust the density of the polymer, for example, methods such as appropriately adjusting the comonomer content, polymerization temperature, catalyst amount, etc. are employed. In addition, the density of the ethylene-propylene copolymer is measured in accordance with JIS-K6922-2:1997 Annex (in the case of low-density polyethylene) (measurement temperature 23°C).

[0028] (c-4) Total number of vinyl and vinylidene In a copolymer obtained by copolymerizing ethylene and one or more α-olefins, even when no active diene monomer is added, due to differences in the manufacturing process mechanism, various double bonds (vinyl, vinylidene, cis-vinylene, trans-vinylene, trisubstituted olefin) may be generated, and their amounts and types also vary. In the present invention, it has been found that among the various double bonds contained in the ethylene-propylene copolymer, vinyl and vinylidene are particularly important in terms of adhesive strength, and an ethylene-propylene copolymer in which the total number of vinyl and vinylidene is larger than that of a normal ethylene-α-olefin copolymer is produced and used as the ethylene-propylene copolymer for the resin composition for lamination, thereby finding and completing the effects of the present invention.

[0029] The ethylene-propylene copolymer (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 chain measured by NMR of 0.35 (pieces / total 1000C) or more, preferably 0.40 to 5.0 (pieces / total 1000C), more preferably 0.45 to 4.5 (pieces / total 1000C), and still more preferably 0.50 to 4.0 (pieces / total 1000C). When the total number of vinyl and vinylidene is within the above range, a resin composition excellent in adhesive strength is obtained, and when it is less than 0.35 pieces, the adhesive strength is not sufficient. The total number of vinyl and vinylidene can be controlled within the above range by appropriately adjusting the selection of an appropriate metallocene catalyst, polymerization temperature, comonomer type, and comonomer amount. The number of these double bonds is the number per 1000 carbon atoms in the main chain and side chains in total, and is a value calculated using the integrated intensity of characteristic peaks in the 1H-NMR spectrum, measured and calculated under the conditions described in the examples below.

[0030] Furthermore, in the present invention, the number of vinyl groups in the ethylene-propylene copolymer (C) preferably satisfies the range of 0.2 (per total 1000C) or more. Also, in the present invention, the number of vinylidene groups in the ethylene-propylene copolymer (C) preferably satisfies the range of 0.12 (per total 1000C) or more.

[0031] (c-5) Relationship between the number of branches (Y) due to the comonomer and the density (X) For the ethylene-propylene copolymer (C) used in the present invention, it is preferable that the number of branches (Y) due to the comonomer and the density (X) satisfy the following formula (1). Formula (1): (Y) ≧ -1360×(X) + 1270 When the density and the number of branches satisfy the relationship of the above formula (1), the number of branches due to the comonomer is sufficiently ensured, and a resin composition excellent in adhesive strength is obtained. Here, the number of branches (Y) due to the comonomer is the number (per total 1000C) per 1000 carbon atoms in the main chain and side chains measured by NMR for the ethylene-propylene copolymer (C). Also, the density (X) is the density of the ethylene-propylene copolymer (C) and is measured as described above.

[0032] Note that 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 the main chain and side chains measured by NMR, and can be calculated from the 13C-NMR spectrum with reference to, for example, E. W. Hansen, R. Blom, and O. M. Bade, Polymer, Vol. 36, p. 4295 (1997). The relationship between the density and the number of branches can be adjusted by the type and ratio of the comonomer to be copolymerized, polymerization conditions such as the polymerization temperature, etc.

[0033] (ii) Polymerization Catalyst and Polymerization Method of Ethylene-Propylene Copolymer (C) The catalyst used for producing the ethylene-propylene copolymer (C) used in the present invention is not particularly limited, but more preferably a metallocene catalyst is used. The metallocene catalyst is not particularly limited, and examples thereof include a catalyst comprising a metallocene compound such as a zirconium compound coordinated with a group having a cyclopentadienyl skeleton and a cocatalyst as catalyst 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, but in order to obtain the ethylene-propylene copolymer (C) with adjusted double bonds according to the present invention, it is desirable to carry out the polymerization at a high temperature of 150 to 330 °C. Therefore, it is preferable to use the high-pressure ionic polymerization method ("Polyethylene Technical Reader", Chapter 4, edited by Kazuo Matsuura and Hisataka Mikami, 2001).

[0034] (2) High-Pressure Radical Polymerization Method Low-Density Polyethylene (D) The high-pressure radical polymerization method low-density polyethylene (D) (hereinafter also simply referred to as low-density polyethylene (D)) used in the present invention is low-density polyethylene (LDPE) obtained by the high-pressure radical polymerization method having the following characteristics (d-1) to (d-2), and is preferably long-chain branched low-density polyethylene. (d-1) MFR (190 °C, 21.18 N load) is 0.1 to 20 g / 10 min (d-2) Density is 0.915 to 0.930 g / cm 3

[0035] (i) Characteristics of High-Pressure Radical Polymerization Method Low-Density Polyethylene (D) (d-1) MFR The melt flow rate (MFR: 190°C, 21.18 N load) of the low-density polyethylene (D) used in the present invention is 0.1 to 20 g / 10 min, preferably 0.5 to 15 g / 10 min, and more preferably 1 to 15 g / 10 min. When the MFR is less than 0.1 g / 10 min, the ductility becomes insufficient and film breakage occurs during high-speed forming. On the other hand, when the MFR exceeds 20 g / 10 min, the molten film becomes unstable. Here, the MFR is a value measured in accordance with the appendix of JIS-K6922-2:1997 (190°C, 21.18 N load).

[0036] (d-2) Density The density of the low-density polyethylene (D) used in the present invention is 0.915 to 0.930 g / cm 3 and preferably 0.916 to 0.926 g / cm 3 and more preferably 0.917 to 0.925 g / cm 3 . When the density is less than 0.915 g / cm 3 , stickiness increases. On the other hand, when it exceeds 0.93 g / cm 3 , the adhesiveness becomes poor. Here, the density is measured in accordance with the appendix of JIS-K6922-2:1997 (in the case of low-density polyethylene) (measurement temperature 23°C).

[0037] (ii) Polymerization method of high-pressure radical polymerization low-density polyethylene (D) The production of the low-density polyethylene (D) used in the present invention is generally carried out by polymerizing ethylene in the presence of a radical generator using a tank reactor or a tubular reactor under the conditions of a polymerization pressure of 1000 to 3000 kg / cm 2 and a polymerization temperature of 150 to 300°C. The MFR can be adjusted by using hydrocarbons such as hydrogen, methane, and ethane as a molecular weight regulator.

[0038] (3) Composition ratio of ethylene·propylene copolymer (C) and low-density polyethylene (D) When the polyethylene resin composition (F) used in the present invention contains an ethylene-propylene copolymer (C) and a low-density polyethylene (D), the ratio of the ethylene-propylene copolymer (C) to the high-pressure radical polymerization method low-density polyethylene (D) is such that (C):(D) is, for example, 1 to 99% by weight: 99 to 1% by weight, preferably 20 to 95% by weight: 5 to 80% by weight, more preferably 30 to 95% by weight: 5 to 70% by weight. Even more preferably, it is 40 to 95% by weight: 5 to 60% by weight. If there is too much ethylene-propylene copolymer (C), the stability of the molten film may decrease, and if there is too much high-pressure radical polymerization method low-density polyethylene (D), the adhesive strength may decrease. In particular, when the ratio (C:D) of the ethylene-propylene copolymer (C) to the high-pressure radical polymerization method low-density polyethylene (D) is 50 to 95% by weight: 5 to 50% by weight, it is preferable because the adhesive strength is higher. In addition to the ethylene-propylene copolymer (C) and the low-density polyethylene (D), an ethylene-α-olefin copolymer (E) may be included.

[0039] (4) Characteristics of the ethylene-α-olefin copolymer (E) (4-1) Monomer composition of the ethylene-α-olefin copolymer (E) The ethylene-α-olefin copolymer (E) used in the present invention is a random copolymer of ethylene and an α-olefin having a constituent unit derived from ethylene as a main component.

[0040] The α-olefin used as a comonomer is preferably an α-olefin having 3 to 12 carbon atoms. Specifically, propylene, 1-butene, 1-pentene, 1-hexene, 1-octene, 1-heptene, 4-methyl-pentene-1, 4-methyl-hexene-1, 4,4-dimethylpentene-1, etc. can be mentioned. Specific examples of such ethylene·α-olefin copolymers include ethylene·propylene copolymers, ethylene·1-butene copolymers, ethylene·1-hexene copolymers, ethylene·1-octene copolymers, ethylene·4-methyl-pentene-1 copolymers, etc. Further, the α-olefin may be one kind or a combination of two or more kinds. When two kinds of α-olefins are combined to form a terpolymer, ethylene·propylene·hexene terpolymers, ethylene·butene·hexene terpolymers, ethylene·propylene·octene terpolymers, ethylene·butene·octene terpolymers, etc. can be mentioned.

[0041] (4-2) Polymerization catalyst and polymerization method of ethylene·α-copolymer (E) The ethylene·α-olefin copolymer (E) used in the present invention can be produced using a Ziegler catalyst or a metallocene catalyst, preferably a metallocene catalyst. Examples of production methods include high-pressure ionic polymerization method, gas-phase method, solution method, slurry method, etc.

[0042] The metallocene catalyst is not particularly limited, but a catalyst similar to those described in Japanese Patent Publication No. 7-508545, that is, for example, a catalyst solution obtained by adding equimolar amounts of tripentafluorophenylboron to 2.0 mmol of the complex dimethylsilylenebis(4,5,6,7-tetrahydroindenyl)hafnium dimethyl and diluting it to 10 liters with toluene can be preferably used. Commercially available products include the Harmolex series manufactured by Nippon Polyethylene Co., Ltd., the Kernel series, the Evolue series manufactured by Prime Polymer Co., Ltd., the Exlene GMH series and the Exlene FX series manufactured by Sumitomo Chemical Co., Ltd.

[0043] (4-3) Characteristics of ethylene·α-olefin copolymer (E) The melt flow rate (MFR: 190 °C, 21.18 N load) and density of the ethylene·α-olefin copolymer (E) used in the present invention are not particularly defined.

[0044] (5) Characteristics of polyethylene resin composition (F) (f-1) MFR The melt flow rate (MFR: 190 °C, 21.18 N load) of the polyethylene resin composition (F) used in the present invention is preferably 1 to 100 g / 10 min, more preferably 1 to 80 g / 10 min, and still more preferably 5 to 60 g / 10 min. When the MFR is less than 1 g / 10 min, the ductility during molding deteriorates and the motor load in the extruder becomes high, which is not preferable. On the other hand, when the MFR exceeds 100 g / 10 min, the state of the molten film during molding becomes unstable, which is not preferable. Here, the MFR is a value measured in accordance with JIS-K6922-2:1997 Annex (190 °C, 21.18 N load).

[0045] (f-2) Density The density of the polyethylene resin composition (F) used in the present invention is preferably 0.88 to 0.94 g / cm 3 and more preferably 0.88 to 0.93 g / cm 3 and still more preferably 0.88 to 0.92 g / cm 3 . When the density is less than 0.88 g / cm 3 , blocking becomes poor, which is not preferable. On the other hand, when the density exceeds 0.94 g / cm 3 , adhesiveness becomes poor, which is not preferable. Here, the density is measured in accordance with JIS-K6922-2:1997 Annex (in the case of low density polyethylene) (measurement temperature 23 °C).

[0046] (6) Other components In the polyethylene resin composition (F) used in the present invention or the resin layer (A) containing the same, if necessary, phenolic, phosphorus-based and other antioxidants commonly used in polyethylene resins, stabilizers such as metal soaps, antiblocking agents, lubricants, dispersants, pigments such as organic or inorganic colorants, antifogging agents such as unsaturated fatty acid esters, antistatic agents, ultraviolet absorbers, light stabilizers, nucleating agents and other additives may be blended. For example, the preferable blending range of the antioxidant is 5000 ppm or less, more preferably 3000 ppm or less, and still more preferably 1000 ppm or less by weight ratio. Also, within a range that does not impair the properties of the polyethylene resin composition layer, 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.), polyethylene resins such as high-density polyethylene (HDPE), adhesive resins such as ethylene-maleic anhydride copolymer, polypropylene resins, polystyrene resins, and other thermoplastic resins may be blended. Further, the polyethylene resin composition (F) of the present invention preferably does not contain a crosslinking agent.

[0047] 2. Substrate layer (B) The substrate layer (B) used in the present invention is a film mainly composed of paper, polypropylene resin, polyester resin (such as polyethylene terephthalate resin), or polyamide resin, and having at least a surface in contact with the resin layer (A) as an essential component. Examples include single-layer films, and laminated films made of the same or different materials such as paper, polypropylene resin, polyester resin (such as polyethylene terephthalate resin), or polyamide resin (such as nylon resin). Films made of polypropylene resin, polyester resin (such as polyethylene terephthalate resin), or nylon resin are preferably stretched films. That is, stretched polypropylene films, stretched polyethylene terephthalate films, or stretched nylon films can be mentioned. Paper is particularly preferable as the substrate layer. When the base material layer (B) contains a resin other than paper, polypropylene resin, polyester resin, and polyamide resin, the resins exemplified as examples of other base material layers described below can be used. The base material layer may be subjected to printing, vapor deposition, various coatings, etc. When a transparent resin is used as the base material layer, the laminate for thermal lamination of the present invention can be used as a printing laminate film for protecting the surface of a printed matter or the surface of the printed surface of a light packaging. On the other hand, when paper or the like is used as the base material layer, the laminate for thermal lamination of the present invention can be used for applications such as heat-laminating a part of a paper bundle, a paper cup, and a paper tray.

[0048] 3. Laminate for Thermal Lamination The laminate of the present invention has at least two layers of a resin layer (A) containing the above-described polyethylene resin composition (F) and a base material layer (B), and the resin layer (A) is formed by directly adhering onto the base material layer (B). A resin layer (A) containing the polyethylene resin composition (F) is formed by directly adhering onto at least one surface of the base material layer (B). There are no restrictions on the configuration of the laminate, but for example, laminates including the following configurations are exemplified. Base material layer (B) / Resin layer (A) containing resin composition (F), Resin layer (A) containing resin composition (F) / Base material layer (B) / Resin layer (A) containing resin composition (F), Base material layer (B) / Resin layer (A) containing resin composition (F) / Base material layer (B), Resin layer (A) containing resin composition (F) / Base material layer (B) / Resin layer (A) containing resin composition (F) / Base material layer (B), Base material layer (B) / Resin layer (A) containing resin composition (F) / Base material layer (B) / Resin layer (A) containing resin composition (F) / Base material layer (B), Base material layer (B) / Resin layer (A) containing resin composition (F) / Other base material layer, Other resin layer / Base material layer (B) / Resin layer (A) containing resin composition (F), Other base material layer / Base material layer (B) / Resin layer (A) containing resin composition (F), Base material layer (B) / Resin layer (A) containing resin composition (F) / Other resin layer Here, the other base material layer is a base material layer different from the base material layer (B), and examples include plastic films or sheets such as polyamide-based resins, polyester-based resins, saponified ethylene-vinyl acetate copolymers, polyvinylidene chloride, polycarbonate, etc., stretched products of the above films or sheets, printed products, secondary processed films or sheets such as vapor deposition products of metals, etc., metal foils or metal plates such as aluminum, iron, copper, alloys mainly composed of these, cellophane, paper, woven fabrics, non-woven fabrics, etc. Also, the other resin layer is a resin layer different from the resin layer (A), and examples 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 ester copolymers (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.

[0049] The method for manufacturing the laminate is not particularly limited. For example, a so-called extrusion coating method in which the polyethylene resin composition (F) is melt-extruded onto the base material layer (B) and the resin layer (A) is laminated is preferable. Further, the above extrusion coating is preferably laminated in one or more layers by methods such as single layer, sandwich lamination, co-extrusion lamination, tandem lamination, etc. The resin layer (A) containing the polyethylene resin composition (F) can be used as an adhesive layer and can also be used as a sealant for the surface layer. According to the present invention, since the adhesion to the base material is good, high-speed molding is possible.

[0050] Also, the method for ensuring adhesion to the paper base material layer is not particularly limited. For example, the surface treatment of the base material may be performed. Examples of the surface treatment method include various treatment methods such as corona discharge treatment method, ozone treatment method, flame treatment method, low-temperature plasma treatment method, etc. A method of blowing ozone onto the molten resin is also included. When a base material layer other than the paper base material is provided, it is preferable to perform an anchor coat treatment as necessary.

[0051] When the laminate for thermal lamination of the present invention is used as a film for print lamination to be laminated on the surface of a printed matter, for example, the surface of the resin layer (A) of the laminate for thermal lamination is brought into contact with the printed surface of paper or the like which is the object of thermal lamination, and then pressure bonding is performed while conveying it between two heating rolls at a temperature of 90 to 120 ° C., so that it can be used for thermal lamination processing. When the laminate for thermal lamination of the present invention is used for applications such as partially thermally laminating a bundle of papers or a paper tray, for example, a part of the surface of the resin layer (A) of one laminate for thermal lamination is brought into contact with a part of the base material layer (B) of the other laminate for thermal lamination, and then they are bonded and heat-pressed to perform thermal lamination. In this way, it is preferable in that lamination can be performed only by heat-pressing without using an adhesive or an organic solvent.

[0052] The laminate for thermal lamination of the present invention is formed by the resin layer (A) containing the above polyethylene resin composition (F), and is excellent in low-temperature heat-sealing strength with a thermal lamination object such as paper and the base material layer (B), and has excellent thermal lamination characteristics. Therefore, it can be used as a bundle of papers, a paper cup, a paper tray, a film for print lamination, a thermal lamination film for protecting the printed surface of a flexible package, etc.

Examples

[0053] The present invention will be specifically described below with reference to examples, but the present invention is not limited thereto. The measurement methods and resins used in the examples and comparative examples are as follows.

[0054] 1. Measurement method (1) Melt flow rate (MFR): The MFR of ethylene-propylene copolymer or other ethylene-α-olefin copolymer, high-pressure radical polymerization method low-density polyethylene, and polyethylene resin composition was measured in accordance with JIS-K6922-2:1997 annex (190 ° C., 21.18 N load). (2) Density: The density of the ethylene-propylene copolymer or other ethylene-α-olefin copolymer, high-pressure radical polymerization low-density polyethylene, and polyethylene resin composition was measured in accordance with Appendix of JIS-K6922-2:1997 (at 23 °C for low-density polyethylene).

[0055] (3) Monomer amount, number of branches, number of double bonds: <Sample Preparation and Measurement Conditions> 200 mg of the sample was placed in an NMR sample tube with an inner diameter of 10 mm φ together with 2.4 ml of o-dichlorobenzene / deuterated benzene = 4 / 1 (volume ratio) and hexamethyldisiloxane, which is a chemical shift reference substance, and dissolved. The NMR measurement was carried out using an AV400M type NMR apparatus of Bruker BioSpin Corporation equipped with a 10 mm φ cryoprobe. 13 The 13C-NMR measurement conditions were as follows: the sample temperature was 120 °C, the pulse angle was 90°, the pulse interval was 20 seconds, and the number of integration times was 128 times, and the measurement was carried out by the broadband decoupling method. 1 The measurement conditions for 1H-NMR were as follows: the sample temperature was 120 °C, the pulse angle was 4.5°, the pulse interval was 2 seconds, and the number of integration times was 512 times. <Calculation Method> (i) Monomer amount, number of branches due to comonomer 13 Using the signal intensity of the 13C-NMR spectrum, the amounts of propylene, hexene, and ethylene were determined from the following equations. C3 (mol%) = I(P) × 100 / [I(P) + I(H) + I(E)] C6 (mol%) = I(H) × 100 / [I(P) + I(H) + I(E)] C2 (mol%) = I(E) × 100 / [I(P) + I(H) + I(E)] Here, I(P), I(H), and I(H) are the amounts represented by the following equations, respectively. I(P) = 0.5 × (I 37.69~37.20 + I 37.90~37.69 + I 37.97~37.90 + I 43.90~42.68 ) + I 46.60~45.39 I(H) = 0.5×(I 34.56~34.22 + I 34.94~34.86 + I 43.60~42.68 ) + 0.5× (I 34.86~34.70 - I 35.80~35.68 ) + I 40.10~39.96 + I 40.80~40.70 I(E) = {0.5×(I 34.94~34.86 + I 37.90~37.69 I 37.97~37.90 + I 34.56~34.22 + I 37.69~37.20 ) + 0.5×(I 34.86~34.70 - I 35.80~35.68 ) + I 24.90~24.70 + I 24.70~24.52 + I 24.52~24.32 + I 27.28~26.83 + I 27.50~27.28 + I 31.50~28.50 - I(H)} / 2 I represents the integrated intensity, and the numerical value of the subscript of I indicates the chemical shift range. For example, I 37.69~37.20 represents the integrated intensity of the 13C signal detected between 37.69 ppm and 37.20 ppm. The chemical shift was set with the 13C signal of hexamethyldisiloxane at 1.98 ppm, and the chemical shifts of the signals from other 13C were based on this. Also, the number of branches per 1000 carbon atoms in the main chain and side chains was determined from the following formula. Number of methyl branches (per 1000C total) = C3(mol%) × 1000 / {C3(mol%) × 3 + C6(mol%) × 6 + C2(mol%) × 2} Number of butyl branches (per 1000C total) = C6(mol%) × 1000 / {C3(mol%) × 3 + C6(mol%) × 6 + C2(mol%) × 2}

[0056] (ii) Number of double bonds The amount of unsaturated bonds per 1000 carbon atoms in the main chain and side chains was 1 determined from the following formula using the signal intensity of the H-NMR spectrum. Number of vinylidene units (units / total 1000C) = Ivd × 1000 / Itotal Number of vinyl units (units / total 1000C) = Ivi × 1000 / Itotal Number of trisubstituted olefin units (units / total 1000C) = Itri × 1000 / Itotal Number of vinylene units (units / total 1000C) = Ivnl × 1000 / Itotal I represents the integrated intensity, and the subscript numerical value of I indicates the range of chemical shift. Here, Ivd 、 Ivi, Itri, Ivnl, and Itotal are respectively the amounts represented by the following formulas as follows. Ivd = (I 4.88~4.44 ) / 2 Ivni = (I 5.52~5.30 ) / 2 Ivi = (I 5.05~4.88 + I 5.85~5.70 ) / 3 Itri = I 5.30~5.05 Itotal = (I 0.00~5.85 ) / 2 However, for example, I 5.52~5.30 represents the integrated intensity of the proton signal detected between 5.52 ppm and 5.30 ppm. The chemical shift was set with the proton signal of hexamethyldisiloxane as 0.09 ppm, and the chemical shifts of the signals from other protons were based on this.

[0057] (4) Melt film stability: (4 - 1) The stability of the melt film was visually observed at an extruder with a diameter of 90 mm, a T-die width of 560 mm, a lip width of 0.8 mm, an air gap of 115 mm, a forming temperature of 320 °C, and a take-up speed of 100 m / min. When the melt film was stable and could be processed, it was marked as "○", and when the melt film was unstable and could not be processed into a uniform thickness, it was marked as "×".

[0058] (5) Heat seal strength (N / 15 mm) Using a laminator with an extruder diameter of 90 mm, from the pay-off machine, kraft paper, a type of paper, with a weight of 50 g / m2 Unwind it to use as a base material, and while applying corona treatment of 30 W·min / m to the kraft surface 2 extrusion lamination was carried out under the conditions of a take-up speed of 100 m / min and a thickness of 20 μm for the polyethylene resin composition (F). Corona treatment of 12 W·min / m was performed again on the resin (A) layer side made of the polyethylene resin composition (F) of the obtained laminate film. 2 As a result, a laminate composed of a paper base material layer (B) and a resin layer (A) was obtained. Using two of the obtained laminates, heat lamination was carried out by overlapping the front and back as shown in Fig. 2. That is, the heat seal strength between the paper (kraft) base material layer (B) side of one laminate and the resin layer (A) side of the other laminate was evaluated. Heat sealing was performed under the conditions of 0.2 MPa and 1 second, and the 180-degree peel strength of a 15-mm width was measured.

[0059] 2. Resin material (1) Ethylene-propylene copolymer (C) or other ethylene-α-olefin copolymer (PE-1) to (PE-4) obtained by the following production method were used as the ethylene-propylene copolymer or other ethylene-α-olefin copolymer of component (C). Their physical property values are shown in Table 1.

[0060] (PE-1) to (PE-4) production method (i) Catalyst preparation 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.

[0061] (ii) Polymerization method Using a stirred autoclave type continuous reactor with an internal volume of 5.0 liters, maintaining the pressure inside the reactor at 80 MPa, while appropriately adjusting ethylene, propylene, and 1-hexene, the raw material gas was continuously supplied at a rate of 40 kg / h. Also, the catalyst solution described in the above item "(i) Preparation of catalyst" was continuously supplied, and the polymerization temperature was appropriately adjusted within the range of 150 to 250 °C to obtain an ethylene-α-olefin copolymer. The physical property values of the obtained ethylene-propylene copolymer or other ethylene-α-olefin copolymers are shown in Table 1.

[0062] (2) High-pressure radical polymerization method low-density polyethylene High-pressure radical polymerization method low-density polyethylenes (PE-5) to (PE-6) having the physical property values shown in Tables 1 to 2 were used.

[0063] (Example 1) As the ethylene-propylene copolymer (C), 67 wt% of (PE-1), and as the high-pressure method low-density polyethylene (D), a high-pressure radical polymerization method long-chain branched low-density polyethylene (PE-5) with an MFR of 4 g / 10 min and a density of 0.918 g / cm 3 A polyethylene resin composition (F) composed of 33 wt% was pelletized with a 40 mm single-screw extruder to obtain pellets of the polyethylene-based composition. Using the pellets obtained above, with a 90 mmφ laminator of an extruder, kraft paper with a basis weight of 50 g / m was fed from the unwind unit as a base material, and while applying a corona treatment of 30 W·min / m to the kraft paper surface 2 The polyethylene resin composition (F) was subjected to extrusion lamination at a take-up speed of 100 m / min and a thickness of 20 μm. Corona treatment of 12 W·min / m was performed again on the polyethylene resin composition (F) layer side of the obtained laminate film 2 to obtain a laminate for thermal lamination, and each evaluation was carried out. The evaluation results of the laminate are shown in Table 1. 2 to obtain a laminate for thermal lamination, and each evaluation was carried out. The evaluation results of the laminate are shown in Table 1.

[0064] (Example 2) In Example 1, pellets were produced and evaluated in the same manner as in Example 1, except that (PE-2) was used instead of (PE-1) as the ethylene-propylene copolymer (C). The evaluation results are shown in Table 1.

[0065] (Comparative Example 1) In Example 1, pellets were produced and evaluated in the same manner as in Example 1, except that an ethylene-α-olefin copolymer (PE-3), which is a copolymer of ethylene, propylene, and 1-hexene, was used instead of the ethylene-propylene copolymer (PE-1) used in Example 1. The evaluation results are shown in Table 1.

[0066] (Comparative Example 2) In Example 1, pellets were produced and evaluated in the same manner as in Example 1, except that an ethylene-α-olefin copolymer (PE-4), which is a copolymer of ethylene and 1-hexene, was used instead of the ethylene-propylene copolymer (PE-1) used in Example 1. The evaluation results are shown in Table 1.

[0067] (Comparative Example 3) In Example 1, pellets were produced and evaluated in the same manner as in Example 1, except that a composition obtained only with (PE-6), which is a high-pressure radical polymerization method low-density polyethylene (D), was used without using the ethylene-propylene copolymer (C). The evaluation results are shown in Table 1.

[0068]

Table 1

[0069] In order to show the relationship between the density of the ethylene-propylene copolymer (C) or other ethylene-α-olefin copolymers of Examples 1 and 2 and Comparative Examples 1 to 3 obtained in Table 1 and the heat-sealing properties during thermo-laminating processing, it is shown as a graph in Figure 3. In the graph, the X-axis (horizontal axis) represents the density of the ethylene-propylene copolymer or other ethylene-α-copolymer used in the study, and the Y-axis (vertical axis) represents the heat seal temperature when the heat seal strength reaches 1.0 N / 15 mm during heat lamination processing. A smaller value on the Y-axis is preferred. As is clear from the results of Table 1 and Figure 3, the laminated polyethylene resin composition according to the examples of the present invention and the laminate obtained therefrom are excellent in melt film stability and have excellent low-temperature heat seal characteristics commensurate with the density during heat lamination processing. On the other hand, when an ethylene-α-olefin copolymer with a small number of branches due to the comonomer and a small number of vinyl and vinylidene groups is used (Comparative Examples 1 and 2), the low-temperature heat seal characteristics commensurate with the density are not good. Also, when only the high-pressure radical polymerization method low-density polyethylene (D) is used without using the ethylene-propylene copolymer (C) (Comparative Example 3), the low-temperature heat seal characteristics were not good.

Industrial Applicability

[0070] The laminate of the present invention can be used as a paper bundle, paper cup, paper tray, film for printed lamination, heat lamination film for protecting the printed surface of flexible packaging, and the like.

Claims

1. having at least two layers of a resin layer (A) and a base material layer (B), the resin layer (A) is formed by being laminated directly on the base material layer (B) or on another resin layer laminated on the base material layer, and is the outermost layer, and the resin layer (A) and the base material layer (B) each satisfy the following characteristics, a heat laminate film for protecting a printed surface. Resin layer (A): containing a polyethylene resin composition (F) containing an ethylene-propylene copolymer (C) having the following characteristics (c-1) to (c-5) (c-1) containing 80 to 98 mol% of structural units derived from ethylene as the main component, 2 to 20 mol% of structural units derived from propylene as an essential sub-component, and may contain up to 7 mol% of structural units derived from a third α-olefin other than ethylene and propylene as a sub-component (However, when containing structural units derived from the third α-olefin, 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-2) MFR (190 ° C, 21.18 N load) is 1 to 100 g / 10 min (c-3) The density is 0.88 to 0.94 g / cm ３ (c-4) The total amount of vinyl and vinylidene in the ethylene-propylene copolymer is 0.35 (pieces / total 1000C) or more (However, the number of vinyl and vinylidene is the number per 1000 carbon atoms in the total of the main chain and side chain measured by NMR.) (c-5) The number of branches (Y) due to the comonomer in the ethylene-propylene copolymer and the density (X) satisfy the relationship of the following formula (1). Formula (1): (Y) ≧ -1360×(X) + 1270 (However, Y is the number per 1000 carbon atoms in the total of the main chain and side chain measured by NMR.) Base material layer (B): a base material mainly composed of paper, polypropylene resin, polyester resin, or polyamide resin

2. The heat laminate film for protecting a printed surface according to claim 1, wherein the polyethylene resin composition (F) further contains a high-pressure radical polymerization low-density polyethylene (D) having the following characteristics (d-1) to (d-2). (d-1) MFR (190 ° C, 21.18 N load) is 0.1 to 20 g / 10 min (d-2) The density is 0.915 to 0.930 g / cm ３

3. The content of the ethylene-propylene copolymer (C) contained in the polyethylene resin composition (F) is 99 to 1% by weight, and it contains 1 to 99% by weight of low-density polyethylene (D) by the high-pressure radical polymerization method. The heat laminating film for protecting a printed surface according to claim 1 or 2, characterized in that it may contain an ethylene-α-olefin copolymer (E). (However, when it contains an ethylene-α-olefin copolymer (E), the total of the ethylene-propylene copolymer (C) and the low-density polyethylene (D) by the high-pressure radical polymerization method does not exceed 100% by weight.)

4. The heat laminating film for protecting a printed surface according to any one of claims 1 to 3, characterized in that the polyethylene resin composition (F) further satisfies the following characteristics (f-1) to (f-2). (f-1) MFR is 1 to 100 g / 10 min (f-2) The density is 0.88 to 0.94 g / cm ３

5. The heat laminating film for protecting a printed surface according to any one of claims 1 to 4, characterized in that the polyethylene resin composition (F) further satisfies the following characteristics (f-1) to (f-2). (f-1) MFR is 5 to 60 g / 10 min The density is 0.88 to 0.92 g / cm ３

6. The heat laminating film for protecting a printed surface according to any one of claims 1 to 5, characterized in that the base material layer (B) is paper, or a stretched polypropylene film, or a stretched polyethylene terephthalate film, or a stretched nylon film.

7. The heat laminating film for protecting a printed surface according to any one of claims 1 to 6, characterized in that the resin layer (A) is formed on the base material layer (B) by an extrusion coating method.

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