TWI569962B - Laminated film - Google Patents

Description

Laminated film

This invention relates to laminated films.

The present invention claims priority based on the Japanese Patent Application No. 2012-116135, filed on May 22, 2012, the entire disclosure of which is incorporated herein.

Conventionally, as a packaging container for storing contents such as foods and drinks, a plastic packaging body is used. The packaging system comprises a substrate that contains the contents and a cover material that seals the substrate. This substrate is used, for example, by vacuum forming or pressure forming to form a laminated film into a shape suitable for a content.

The required performance of the film used for such a package is generally, for example, gas barrier properties, pinhole resistance, and the like. Further, in recent years, in addition to the functions of protecting such contents, it is also required to be suitable for the performance of the contents, and such required characteristics include, for example, the ability to recognize and distinguish the transparency of the contents, and to make the products more beautiful. Sex and so on.

Further, one of the other required characteristics may be curling. Here, the curling property means that the curl occurring in the flange portion of the package when the substrate and the lid member are sealed can be made small. When the curling property is poor, that is, the curl generated in the flange portion of the package body is large, there is a defect in the conveyance of the belt conveyor at the time of manufacture, or the printed label must be pasted. In the case of a package, there is a concern that the problem cannot be properly adhered, and thus a laminate excellent in curling property is required.

In order to solve such a problem, a package comprising a gas barrier multilayer film as disclosed in Patent Document 1 has been developed. However, the curling property is not fundamentally solved, and development of a package that further satisfies the above-described required characteristics is required. .

[Previous Technical Literature] [Patent Literature]

[Patent Document 1] Japanese Patent Laid-Open Publication No. 2010-234718

An object of the present invention is to provide a laminated film excellent in curling property, transparency, and gloss.

Such an object can be achieved by the present invention described in the following (1) to (13).

(1) A laminated film in which a surface layer, an intermediate layer, and a heat seal layer are laminated in this order, wherein the heat seal layer contains a heat seal layer (A), and the heat seal The layer (A) contains a linear low-density polyethylene resin obtained by copolymerizing ethylene and an α-olefin having 6 carbon atoms.

(2) The laminated film according to the above (1), wherein the heat seal layer further contains another heat seal layer (B).

(3) The laminated film according to the above item (2), wherein the heat-sealing layer (B) comprises a linear low-density polyethylene obtained by copolymerizing ethylene and an alpha olefin having 8 carbon atoms. Resin.

(4) The laminated film according to any one of the above-mentioned items, wherein the heat-sealing layer (A) has a thickness of from 3 μm to 100 μm.

The laminated film according to any one of the items (2) to (4), wherein the heat-sealing layer (B) has a thickness of from 3 μm to 100 μm.

(6) The laminated film according to any one of the above items (2) to (5), wherein the thickness of the heat seal layer (A) is set to H (A), the thickness of the heat seal layer (B) When H (B) is satisfied, the thickness ratio represented by H (A) / H (A) is 1.0 or more and 5.0 or less.

(7) The laminated film according to any one of the above (1), wherein the surface layer comprises a polypropylene resin.

(8) The laminated film according to any one of the above items, wherein the intermediate layer comprises a polyamide resin.

(9) The laminated film according to the above (1) to (8), wherein between the surface layer and the intermediate layer, or/and between the intermediate layer and the heat seal layer (A), The adhesive layer of the resin.

(10) The laminated film according to any one of the above aspects, wherein the laminated film has a thickness of 50 μm or more and 250 μm or less.

The laminated film according to any one of the above aspects, wherein the laminated film has a haze of 15% or less and a surface gloss (gloss value) of 100 or more.

(12) A substrate comprising the laminated film according to any one of the above items (1) to (11).

(13) A package comprising the substrate according to (12) above.

According to the present invention, a laminated film excellent in curling property, transparency, and gloss can be provided.

1‧‧‧ surface layer

2‧‧‧Intermediate

3‧‧‧ Heat seal layer

31‧‧‧Heat seal layer (A)

32‧‧‧Heat seal layer (B)

4‧‧‧Next layer

41‧‧‧Next layer (X)

42‧‧‧Next layer (Y)

100‧‧‧ laminated film

200‧‧‧Substrate

201‧‧‧The recess of the substrate

202‧‧‧Cleaning

300‧‧‧Package

Fig. 1 is a cross-sectional view showing a laminated film according to a first embodiment of the present invention.

Fig. 2 is a cross-sectional view showing a laminated film according to a second embodiment of the present invention.

Fig. 3 is a cross-sectional view showing a substrate formed by using the laminated film of the present invention.

Fig. 4 is a cross-sectional view showing a package body including the laminated film of the present invention.

[Formation for implementing the invention]

The present invention will be described in detail based on preferred embodiments shown below.

<First Embodiment>

First, the first embodiment of the laminated film of the present invention will be described.

FIG. 1 is a cross-sectional view showing an example of a laminated film 100 according to the first embodiment.

As shown in FIG. 1, the laminated film 100 of the first embodiment of the present invention is disposed in the order of the surface layer 1, the intermediate layer 2, and the heat seal layer 3. The heat seal layer 3 includes a heat seal layer (A) 31 composed of a linear low-density polyethylene resin obtained by copolymerizing ethylene and an α-olefin having 6 carbon atoms, and a heat seal layer ( B) 32.

Hereinafter, each configuration of the laminated film 100 will be described in detail.

<surface layer>

The material of the surface layer 1 is, for example, a polypropylene resin, a polyester resin, a polyamide resin, and an ethylene-vinyl alcohol copolymer (hereinafter referred to as "EVOH resin"). Specifically, in the case where the package after the contents of the packaged food, beverage, or industrial member is subjected to heat sterilization treatment, the surface layer 1 is exposed to hot water and high-temperature steam. Therefore, the material of the surface layer 1 is preferably a polypropylene resin having a high heat resistance, a polyamide resin, or a polyester resin having a high melting point, such as a polyethylene terephthalate resin. Among them, in view of ease of handling, low raw material unit price, and good curling property after cooking, it is more preferable to use a polypropylene-based resin.

For the polypropylene resin, for example, a crystalline polypropylene resin or the like can be used. Specifically, as the crystalline polypropylene-based resin, at least one of a crystalline propylene homopolymer, a crystalline propylene-ethylene random copolymer, a crystalline propylene-α-olefin random copolymer, ethylene, and an α-olefin can be used. A crystalline block copolymer with propylene or the like. The above α-olefin can use 1-butene, An α-olefin having 4 to 10 carbon atoms such as 1-pentene, 1-hexene, 1-octene or 1-decene. Further, these α-olefins may be copolymerized in an arbitrary ratio.

The thickness of the surface layer 1 is not particularly limited, and is preferably 3 μm or more and 100 μm or less, more preferably 5 μm or more and 85 μm or less, and still more preferably 7 μm or more and 70 μm or less. When the thickness of the surface layer 1 is within the above range, the laminated film 100 having a good appearance excellent in gloss can be obtained relatively inexpensively.

<intermediate layer>

The material of the intermediate layer 2 is, for example, a polyamine-based resin or an EVOH resin. Among them, a polyamine-based resin is preferably used. By using a polyamide resin, the laminated film 100 which has both gas barrier property and pinhole resistance can be obtained.

Examples of the polyamine resin include nylon-6,6, nylon-6,10, nylon-6T composed of hexamethylenediamine and terephthalic acid, and nylon composed of hexamethylenediamine and isophthalic acid. -6I, nylon-9T composed of decane diamine and terephthalic acid, nylon-M5T composed of methyl pentane diamine and terephthalic acid, and nylon composed of caprolactam and laurylamine -6, 12, etc. Further, a copolymer of the above-mentioned resin and at least one of Nylon-6, Nylon-11, and Nylon-12 may be used. These resins may be used singly or in combination of two or more. Further, an amorphous aromatic polyamine obtained by a polycondensation reaction of an aliphatic diamine such as hexamethylenediamine or a dicarboxylic acid such as terephthalic acid or isophthalic acid or a derivative thereof may be used. (Amorphous nylon).

The thickness of the intermediate layer 2 is not particularly limited, and is preferably 3 μm or more and 100 μm or less, more preferably 5 μm or more and 70 μm or less, and still more preferably 10 μm or more and 50 μm or less. When the thickness of the intermediate layer 2 is within the above range, the laminated film 100 excellent in pinhole resistance can be obtained.

<heat seal layer>

The heat seal layer 3 is composed of a heat seal layer (A) 31 and another heat seal layer (B) 32, It has a function of resisting physical properties and a function of sealing compatibility with a sealed target material. The content-resistance property refers to a property in which the heat-sealing layer does not lose the function of sealing the target material due to the drug or the oil component when the content is a drug or a foodstuff containing a large amount of oil.

The heat seal layer 3 contains a heat seal layer (A) 31. Further, the heat seal layer (A) 31 is composed of a linear low-density polyethylene resin obtained by copolymerizing ethylene and an α-olefin having 6 carbon atoms. The heat seal layer (A) 31 can obtain a heat seal layer 3 excellent in transparency and sealing strength by using a linear low-density polyethylene resin. Further, among the linear low-density polyethylene resins, a buffer-like and processability can be obtained by using a linear low-density polyethylene resin obtained by copolymerizing ethylene and an α-olefin having 6 carbon atoms. Since all of them are excellent heat-sealing layers 3, a laminated film excellent in curling property can be obtained.

The thickness of the heat seal layer (A) 31 is not particularly limited, and is preferably 3 μm or more and 100 μm or less, more preferably 5 μm or more and 80 μm or less, and still more preferably 7 μm or more and 50 μm or less. When the thickness of the heat seal layer (A) 31 is within the above range, the laminated film 1 having a good appearance can be obtained relatively inexpensively.

The heat seal layer 3 further contains another heat seal layer (B) 32. The material of the heat seal layer (B) 32 may, for example, be a low density polyethylene resin, a linear low density polyethylene resin, a medium density low density polyethylene resin, a high density polyethylene resin, a polypropylene resin, or ethylene vinyl acetate. Ester copolymer, ethylene-methyl methacrylate copolymer, ethylene-ethyl acrylate copolymer, ethylene-methyl acrylate copolymer, ethylene-ethyl acrylate-maleic anhydride copolymer, ethylene-acrylic acid copolymer, ethylene- A methacrylic acid copolymer, an ionic polymer or the like. Among these, a linear low-density polyethylene resin and an ethylene-vinyl acetate copolymer are preferred from the viewpoints of excellent transparency, sealing strength, and curl after cooking. Further, from the viewpoint of excellent cushioning properties, workability, and strength, a linear low-density polyethylene resin obtained by copolymerizing ethylene and an α-olefin having 8 carbon atoms is preferably used.

In addition, the heat seal layer 3 may also contain the heat seal layer (B) 32 as needed.

The thickness of the heat seal layer (B) 32 is not particularly limited, and is preferably 3 μm or more and 100 μm or less, more preferably 5 μm or more and 80 μm or less, and still more preferably 7 μm or more and 50 μm or less. When the thickness of the heat seal layer (B) 32 is within the above range, a laminated film having a good appearance can be obtained relatively inexpensively.

The heat seal layer 3 contains, for example, a heat seal layer (A) 31 composed of a linear low-density polyethylene resin obtained by copolymerizing ethylene and an α-olefin having 6 carbon atoms, and A heat seal layer (B) 32 comprising a linear low-density polyethylene resin obtained by copolymerizing ethylene and an alpha olefin having 8 carbon atoms is preferable. By including the heat seal layer (A) 31 and the heat seal layer (B) 32 in the heat seal layer 3, a laminated film having more excellent curling properties can be obtained.

When the thickness of the heat seal layer (A) 31 is H (A) and the thickness of the heat seal layer (B) 32 is H (B), the thickness is represented by H (A) / H (B) The ratio is preferably 1.0 or more and 5.0 or less, more preferably 1.4 or more and 4.2 or less. By setting the thickness ratio represented by H(A)/H(B) within the above range, curling after cooking can be suppressed.

The thickness of the heat seal layer 3 is not particularly limited, and is preferably 3 μm or more and 200 μm or less, more preferably 20 μm or more and 70 μm or less, still more preferably 30 μm or more and 60 μm or less, and most preferably 35 μm or more and 55 μm or less. When the thickness of the heat seal layer 3 is within the above range, a laminated film having a good appearance can be obtained relatively inexpensively.

<Second embodiment>

Next, a second embodiment of the laminated film of the present invention will be described.

Fig. 2 is a cross-sectional view showing an example of the laminated film 100 of the second embodiment.

As shown in FIG. 2, the laminated film 100 according to the second embodiment of the present invention is in the order of the surface layer 1, the subsequent layer (X) 41, the intermediate layer 2, the subsequent layer (Y) 42, and the heat seal layer 3. And configured. The heat seal layer 3 contains a heat seal layer (A) 31 composed of a linear low-density polyethylene resin obtained by copolymerizing ethylene and an α-olefin having 6 carbon atoms, and a heat seal layer ( B) 32.

In the following, the respective configurations of the laminated film 100 in the second embodiment will be described in detail, and the differences from the first embodiment will be mainly described, and the description of the same matters will be omitted. In FIG. 2, the same components as those of the first embodiment are denoted by the same reference numerals as those of FIG. 1 described above.

In the surface layer 1, the intermediate layer 2, the heat seal layer (A) 31, and the heat seal layer (B) 32 in the present embodiment, the surface layer 1, the intermediate layer 2, and the heat seal layer of the first embodiment can be used, respectively. (A) 31 and the heat seal layer (B) 32 are the same.

<Next layer>

The laminated film 100 in the present embodiment has, as shown in FIG. 2, between the surface layer 1 and the intermediate layer 2, or between the intermediate layer 2 and the heat seal layer (A) 31, and has an adhesive resin. Then layer 4. When the adhesive layer between the surface layer 1 and the intermediate layer 2 is used as the adhesive layer (X) 41 and the adhesive layer between the intermediate layer 2 and the heat seal layer (A) 3 as the adhesive layer (Y) 42, The layer (X) 41 and the subsequent layer (Y) 42 are such that the layers are located between the two layers of the bonding layer (here, between the surface layer 1 and the intermediate layer 2, or between the intermediate layer 2 and the heat sealing layer (A) 3 The bonding strength between the two is improved, and the stiffness, pinhole resistance, flexibility, formability, and the like of the laminated film 100 are improved.

Next, a material of the layer (X) 41 and the layer (Y) 42 can be a known adhesive resin, for example, an adhesive polyolefin resin. Specifically, the material of the subsequent layer may be, for example, an ethylene-methacrylate-glycidyl acrylate terpolymer, or a monobasic acid unsaturated fatty acid, a dibasic acid unsaturated fatty acid, or such an acid anhydride and various polyolefins. Grafted (manual acid grafted ethylene-vinyl acetate copolymer, maleic acid grafted ethylene-α-olefin copolymer, etc.). As the monobasic acid unsaturated fatty acid, acrylic acid, methacrylic acid or the like can be used. As the dibasic acid unsaturated fatty acid, maleic acid, fumaric acid, itaconic acid or the like can be used. another Further, the materials of the subsequent layer (X) 41 and the subsequent layer (Y) 42 may be the same or different.

The thickness of the layer (X) 41 is not particularly limited, and is preferably 2 μm or more and 50 μm or less, and more preferably 3 μm or more and 40 μm or less. When the thickness of the layer (X) 41 is within the above range, the laminated film 100 imparting good adhesion strength can be obtained relatively inexpensively.

The thickness of the layer (Y) 42 is not particularly limited, and preferably 2 μm or more and 70 μm or less, and preferably 3 μm or more and 60 μm or less. When the thickness of the layer (Y) 42 is within the above range, the laminated film 100 imparting good adhesion strength can be obtained relatively inexpensively.

<Method for Producing Laminated Film>

Next, a method of manufacturing the laminated film 100 shown in Fig. 2 will be described.

The laminated film 100 as described above can be manufactured by separately manufacturing a surface layer 1, an intermediate layer 3 having an adhesive layer (X) 41, and a heat seal layer 3 having an adhesive layer (Y) 42, respectively, and then using a laminator It can be obtained by joining these. In addition, the laminated film 100 may also have a surface layer 1, an intermediate layer 3 having an adhesive layer (X) 41, and an adhesive layer by air-cooling or water-cooling co-extrusion or a co-extrusion T-die method. The heat seal layer 3 of (Y) 42 is obtained by film formation. In particular, the method of forming a film by the co-extrusion T-die method is preferable from the viewpoint of thickness control and transparency of the laminated film 100, and film formation can be carried out by a suitable feeding module and a die. .

The thickness of the laminated film 100 obtained by the above-described production method is not particularly limited, and is preferably 50 μm or more and 250 μm or less, and more preferably 90 μm or more and 180 μm or less. By setting the thickness of the laminated film 100 within the above range, a laminated film having moderate strength and flexibility can be obtained.

The haze of the laminate film is not particularly limited, and is preferably 15% or less and more preferably 12% or less. It becomes clear that the haze of the laminated film is within the range described above. Identify the content.

The haze is calculated by the following method.

According to JIS K 7136, a sheet-like sample having a length of 50 mm and a width of 50 mm was cut out from the center of the sheet, and the measured value was used as the haze using NDH-2000 manufactured by Nippon Denshi Industrial Co., Ltd.

The surface glossiness (gloss value) of the laminated film is not particularly limited, and is preferably 100 or more, more preferably 120 or more. By making the surface glossiness (gloss value) of the laminated film within the above-described range, the appearance of the content can be improved.

The surface glossiness (gloss value) was calculated by the following method.

Based on JIS Z 8741, the surface glossiness of the surface of the film was measured under the conditions of an entrance and exit angle of 60° using a portable gloss meter PG-1 manufactured by Nippon Electric Co., Ltd. The same measurement was performed five times on the same sample, and the average value of the obtained surface gloss was taken as the surface glossiness of the sample.

<substrate>

Next, the substrate of the present invention will be described.

Fig. 3 is a view showing an example of the substrate 200 of the present invention.

As shown in FIG. 3, the substrate 200 of the present invention is formed of the above-described laminated film 100. The substrate 200 is produced by forming a recess (cavity) 201 in the laminated film 100. The recess 201 can accommodate contents such as foodstuffs, beverages, or industrial parts.

Further, in the substrate 200, the laminated film 100 is formed such that the surface layer 1 is outside and the heat seal layer 3 is inside.

<Cover material>

The material of the cover material may be, for example, a biaxially stretched polypropylene film, a biaxially stretched polyethylene terephthalate film which vapor-deposits a metal oxide, and a polyethylene tree. A film in which a grease is laminated or the like.

<package>

As shown in FIG. 4, the package 300 of the present invention comprises a substrate 200 and a lid member 202. After the contents are received in the recess 201 of the substrate, the lid member 202 is sealed to the substrate 200 and sealed. The recess 201 of the substrate 200. Since the substrate 200 is configured by the above-described laminated film 100, the package 300 has excellent pinhole resistance and gas barrier properties, and can further form a package excellent in curling property, transparency, and gloss.

[Examples]

Hereinafter, the present invention will be described in detail based on examples and comparative examples, but the present invention is not limited thereto.

(Example 1) <Manufacture of laminated film>

In order to obtain the laminated film 100, a polypropylene resin (manufactured by Sumitomo Chemical Co., Ltd., trade name: Nobrene FL8115) was prepared as a resin constituting the surface layer 1. An adhesive resin (manufactured by Mitsui Chemicals, Inc., trade name: QF551) was prepared as a resin constituting the adhesive layer 41. Polyacetamide resin (manufactured by Ube Industries, Ltd., trade name: 1030B2) was prepared as a resin constituting the intermediate layer 2. An adhesive resin (manufactured by Mitsui Chemicals, Inc., trade name: NF536) was prepared as a resin constituting the adhesive layer 42. A linear low-density polyethylene resin (manufactured by Dow Chemical Co., Ltd., trade name: DOWLEX XUS60901.07) obtained by copolymerizing ethylene and an α-olefin having 6 carbon atoms was prepared as the heat-sealing layer (A) 31.

Using the feed module and the die, the polypropylene resin as the surface layer 1, the above-mentioned adhesive resin as the adhesive layer 41, the polyamide resin as the intermediate layer 2, and the above-mentioned adhesive resin as the adhesive layer 42 And a linear low-density polyethylene resin obtained by copolymerizing the ethylene and the α-olefin having 6 carbon atoms as the heat-sealing layer (A) 31 Coextruded to produce a laminated film 100.

The entire thickness of the laminated film 100 of Example 1 was 150 μm, the thickness of the surface layer 1 was 40 μm, the thickness of the subsequent layer 41 was 8 μm, the thickness of the intermediate layer 2 was 40 μm, and the thickness of the subsequent layer 42 was 8 μm, and the heat seal layer ( A) 31 has a thickness of 54 μm.

<Manufacture of Substrate>

By using a deep drawing type automatic vacuum packaging machine (manufactured by MULTIVAC, model: R530), a long side of 155 mm, a short side of 112 mm, and a drawing depth of 65 mm were formed on the obtained laminated film at a molding temperature of 95 degrees. A recess (recess) to produce the substrate 200.

<Manufacture of package body>

The substrate 300 was formed by sealing ONy/LL (manufactured by letterpress printing company, trade name, thickness: 65 μm) as a lid member 202 and a substrate on which the above-described concave portion was formed under the conditions of a sealing temperature of 140 °C.

(Example 2)

A linear low-density polyethylene resin (manufactured by Dow Chemical Co., Ltd., trade name: DOWLEX 2032) prepared by copolymerizing ethylene and an alpha olefin having 8 carbon atoms as a heat seal layer (B) 32 is prepared. The preparation was carried out in the same manner as in Example 1.

Using the feed module and the die, the polypropylene resin as the surface layer 1, the above-mentioned adhesive resin as the adhesive layer 41, the polyamide resin as the intermediate layer 2, and the above-mentioned adhesive resin as the adhesive layer 42 a linear low-density polyethylene resin obtained by copolymerizing the ethylene and 6 carbon atoms of the α-olefin as the heat-sealing layer (A) 31, and the ethylene as the heat-sealing layer (B) 32 The linear low-density polyethylene resin copolymerized with an alpha olefin having 8 carbon atoms is co-extruded to produce a laminated film 100.

The entire thickness of the laminated film 100 of Example 2 was 150 μm, the thickness of the surface layer 1 was 40 μm, the thickness of the subsequent layer 41 was 8 μm, the thickness of the intermediate layer 2 was 40 μm, and the thickness of the subsequent layer 42 was 8 μm, and the heat seal layer ( A) 31 has a thickness of 36 μm and the heat seal layer (B) has a thickness of 18 μm.

(Example 3)

Prepared in the same manner as in Example 1 except that a linear low-density polyethylene resin (manufactured by PRIMERPOLYMER Co., Ltd., trade name: MORETEC 0438CN) was prepared as the heat seal layer (B) 32.

Using the feed module and the multi-manifold die, the polypropylene resin as the surface layer 1 , the above-mentioned adhesive resin as the adhesive layer 41 , the polyamine resin as the intermediate layer 2 , and the adhesive layer 42 as the adhesive layer 42 The above-mentioned adhesive resin, a linear low-density polyethylene resin obtained by copolymerizing the ethylene and an α-olefin having 6 carbon atoms as the heat-sealing layer (A) 31, and a heat-sealing layer (B) 32 The linear low-density polyethylene resin (manufactured by PRIMERPOLYMER Co., Ltd., trade name: MORETEC 0438CN) was co-extruded to prepare a laminated film 100.

The entire thickness of the laminated film 100 of Example 3 was 150 μm, the thickness of the surface layer 1 was 40 μm, the thickness of the subsequent layer 41 was 8 μm, the thickness of the intermediate layer 2 was 40 μm, and the thickness of the subsequent layer 42 was 8 μm, and the heat seal layer ( A) 31 has a thickness of 36 μm and the heat seal layer (B) has a thickness of 18 μm.

(Example 4)

The same procedure as in Example 2 was carried out except that the ratio of H(A)/H(B) (thickness of sealant) was 4.4.

(Comparative Example 1)

In addition to preparing low-density polyethylene (referred to as "LDPE") (Ube Maruyama Co., Ltd. The system, product name: F222NH) was carried out in the same manner as in Example 1 except that the heat seal layer (A) 31 was used.

The entire thickness of the laminated film of Comparative Example 1 was 150 μm, the thickness of the surface layer 1 was 40 μm, the thickness of the subsequent layer 41 was 8 μm, the thickness of the intermediate layer 2 was 40 μm, and the thickness of the subsequent layer 42 was 8 μm, and the heat seal layer (A). The thickness of 31 is 54 μm.

(Comparative Example 2)

All of them were carried out in the same manner as in Example 1 except that LDPE (manufactured by Ube Maruzen Co., Ltd., trade name: Z322) was prepared as the heat seal layer (A) 31.

The entire thickness of the laminated film of Comparative Example 2 was 150 μm, the thickness of the surface layer 1 was 40 μm, the thickness of the subsequent layer 41 was 8 μm, the thickness of the intermediate layer 2 was 40 μm, and the thickness of the subsequent layer 42 was 8 μm, and the heat seal layer (A). The thickness of 31 is 54 μm.

The laminate film and the package obtained in the examples and the comparative examples were subjected to the following evaluations. At the same time, it also indicates the evaluation project and content.

<curlability>

After standing in a 97 ° C water bath for 40 minutes, the substrate side of the package was placed upside down on a horizontally placed measuring stand, and the curl height of the four corners of the package was measured. Each symbol is as follows. In addition, the evaluation was performed at n=10.

○: The average of the curl heights of the four corners is 10 mm or less.

×: The average of the curl heights of the four corners exceeds 10 mm.

<Haze and surface gloss (gloss value)>

In the haze, a square sheet sample having a length of 50 mm and a width of 50 mm was cut out from the center of the sheet in accordance with JIS K 7136, and a value measured by NDH-2000 manufactured by Nippon Denshi Co., Ltd. was used as the haze.

The surface glossiness (gloss value) was measured by using a portable gloss meter PG-1 manufactured by Nippon Electric Co., Ltd. in accordance with JIS Z 8741, and the surface glossiness of the surface of the film was measured under the condition of an entrance angle of 60°. The same measurement was performed five times on the same sample, and the average value of the obtained surface gloss was taken as the surface glossiness of the sample.

The evaluation results of the above respective examples and comparative examples are shown in Table 1.

As a result, it is apparent from the table that Examples 1 to 4 showed good curling property, haze, and surface glossiness, and Comparative Examples 1 and 2 were compared with Examples 1 to 4, and their curling property, haze, or Either of the surface gloss is insufficient.

[Industrial use possibilities]

The laminated film of the present invention can be used for packaging applications of foods, pharmaceuticals, industrial parts, and electronic materials requiring gas barrier properties and pinhole resistance. Moreover, the laminated film can be suitably used, for example, as a packaging film for a bag-in-box inner bag which is filled with a high liquidity like a liquid, or processed meat, processed aquatic products, and electronics. Packaging film for pillow packaging, vacuum forming packaging, etc. used for packaging of materials. In particular, the laminated film can be suitably used as a packaging film for an electronic component such as a capacitor having a hard corner, or a package of food having an indefinite shape and a hard portion such as a meat, a food containing a lot of spices, and a shell. Use a membrane.

1‧‧‧ surface layer

2‧‧‧Intermediate

3‧‧‧ Heat seal layer

31‧‧‧Heat seal layer (A)

32‧‧‧Heat seal layer (B)

100‧‧‧ laminated film

Claims (11)

A laminated film in which a surface layer, an intermediate layer, and a heat-sealing layer are laminated in a layered manner, wherein the heat seal layer comprises a heat seal layer (A) and a heat seal layer (B) The heat seal layer (A) comprises a linear low density polyethylene resin obtained by copolymerizing ethylene and an alpha olefin having 6 carbon atoms; the heat seal layer (B) is comprised by A linear low-density polyethylene resin obtained by copolymerizing ethylene and an alpha olefin having 8 carbon atoms. The laminated film of claim 1, wherein the heat seal layer (A) has a thickness of from 3 μm to 100 μm. The laminated film of claim 1, wherein the heat seal layer (B) has a thickness of from 3 μm to 100 μm. The laminated film of claim 1, wherein when the thickness of the heat seal layer (A) is H (A) and the thickness of the heat seal layer (B) is H (B), The ratio of the thickness represented by (A) / H (B) is 1.0 or more and 5.0 or less. The laminated film of claim 1, wherein the surface layer comprises a polypropylene resin. The laminated film of claim 1, wherein the intermediate layer comprises a polyamide resin. The laminated film of claim 1, wherein an adhesive layer comprising an adhesive resin is provided between the surface layer and the intermediate layer, or between the intermediate layer and the heat seal layer (A). The laminated film of claim 1, wherein the laminated film has a thickness of 50 μm or more and 250 μm or less. The laminated film of claim 1, wherein the laminated film has a haze of 15% or less and a surface gloss (gloss value) of 100 or more. A substrate comprising the laminated film according to any one of claims 1 to 9. A package comprising a substrate as in claim 10 of the patent application.