JP2009045762A - Composite film for laminate - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a composite film for a laminate which is free of a bump, a sag and a curl and excellent in flexural resistance. <P>SOLUTION: The composite film for laminate consists of an outer layer, an intermediate layer and an inner layer, wherein the outer layer comprises at least one layer of a polyamide resin layer, the intermediate layer comprises at least one layer of a cyclic polyolefin resin layer and the inner layer comprises at least one heat seal layer. The thickness of the cyclic polyolefin resin layer is made ≥3% and <20% of the composite film total thickness, and its thickness is made <30 μm. The number of pinholes of the film is ≤20 when a 500-cycles bending test is conducted continuously at the speed of 40 cycles per minute under the conditions of 5°C and 40 %RH using a Gelbo Flex Tester. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a composite film for laminating, and more particularly to a composite film for laminating that can be suitably used as a bottom material and a lid material for deep drawing.

  Conventionally, a raw composite film having an oxygen barrier layer and a heat seal layer has been used as a raw material for laminating a deep drawing bottom material or a lid material. Then, a stretched polyethylene terephthalate film, a stretched polypropylene film or an unstretched polypropylene film was laminated on this oxygen barrier layer to produce a bottom material or lid for deep drawing.

  However, such an original fabric composite film is flexible and easily stretched, and the film is liable to bend and sag. Therefore, it is difficult to control the tension during lamination. In addition, since the laminated structure is asymmetric, the composite film is easily curled and is difficult to laminate with a stretched polyethylene terephthalate film or the like.

As a film having waist and rigidity, Patent Document 1 describes a coextruded composite film including a saponified ethylene-vinyl acetate copolymer layer and a cycloolefin polymer layer.
JP 2003-191380 A

  However, in the coextruded composite film described in Patent Document 1, the thickness of the cycloolefin polymer layer is set to 30 μm or more in order to improve the stiffness and moisture resistance of the film, and the co-extruded composite film having such a cycloolefin polymer layer is provided. The extruded composite film may have poor flex resistance. Here, “flexibility” means durability when the film is twisted. For example, when used in food packaging applications, when the film is twisted due to external force generated during transportation, A property that does not cause problems such as pinholes. Moreover, in patent document 1, the problem of the curl in the above-mentioned composite film for lamination was not considered.

  Then, this invention makes it a subject to provide the composite film for laminates which is excellent in bending resistance which does not produce a bump, sagging, and curl.

  In order to solve the above problems, the present inventor has intensively studied the layer structure of the film and the composition of each layer, and as a result, has completed the following present invention.

  The first aspect of the present invention is a composite film comprising an outer layer, an intermediate layer, and an inner layer, wherein the outer layer includes at least one polyamide resin layer, the intermediate layer includes at least one cyclic polyolefin resin layer, and the inner layer includes at least Including one heat seal layer, the thickness of the cyclic polyolefin resin layer is 3% or more and less than 20% of the total thickness of the composite film, the thickness of the cyclic polyolefin resin layer is less than 30 μm, 5 ° C., 40% Under the condition of RH, the number of pinholes is 20 or less when a 500-cycle bending test (gelboflex test) is performed continuously at a rate of 40 cycles per minute using a gelboflex tester. It is a composite film for lamination characterized by being.

  Since the composite film for laminating according to the first aspect of the present invention includes a polyamide resin layer (hereinafter, may be abbreviated as “PA layer”) as an outer layer, it has pinhole resistance and deep drawability. Can do. Moreover, since the cyclic polyolefin resin layer is provided as the intermediate layer, the composite film can be prevented from curling and the waist can be imparted to the composite film. Thereby, workability | operativity which laminates a composite film on another film becomes favorable (lamination suitability becomes favorable). Moreover, since the heat seal layer is provided as the inner layer, heat sealability can be imparted to the composite film.

  Moreover, bending resistance can be provided to a composite film by making a cyclic polyolefin resin layer into predetermined thickness. Thereby, the number of pinholes can be reduced to 20 or less in the gelboflex test under the above conditions.

  In the first aspect of the present invention, the heat seal layer comprises low density polyethylene (LDPE), linear low density polyethylene (LLDPE), ethylene-vinyl acetate copolymer (EVA), and ethylene-acrylic acid copolymer (EAA). , Ethylene-ethyl acrylate copolymer (EEA), ethylene-methacrylic acid copolymer (EMAA), ethylene-methyl methacrylate copolymer (EMMA), ethylene-methyl acrylate copolymer (EMA), ethylene- It is preferably composed of at least one selected from the group consisting of an ionomer of an acrylic acid copolymer (EAA) and an ionomer of an ethylene-methacrylic acid copolymer (EMAA).

  In the first invention, the glass transition point (Tg) of the cyclic polyolefin resin constituting the cyclic polyolefin resin layer is preferably 60 ° C. or higher and 140 ° C. or lower. By using a cyclic polyolefin resin having such a glass transition point, it is possible to prevent the film from being softened during film storage and to be squeezed into a film wound around a paper tube. In addition, it is possible to prevent blisters, gels and fish eyes during film formation.

  In the first aspect of the present invention, the cyclic polyolefin resin layer is composed of 5% by mass or more and 50% by mass or less of low density polyethylene (LDPE) and / or linear, based on 100% by mass of the entire resin constituting the cyclic polyolefin resin layer. It preferably contains low density polyethylene (LLDPE). As a result, it is possible to prevent blister / gel / fish eyes during film formation. In addition, the balance between flexibility and waist of the film can be achieved.

  In the first aspect of the present invention, the outer layer preferably includes at least one ethylene-vinyl acetate copolymer saponified material layer (hereinafter sometimes abbreviated as “EVOH layer”). Thereby, an oxygen barrier property can be imparted to the composite film.

  In the first aspect of the present invention, at least one adhesive layer may be provided between the respective layers. Thereby, the adhesive strength between each layer can be raised.

  In the first aspect of the present invention, an easy peel property may be imparted to the heat seal layer. In that case, the easy peel strength is 25 ° C. and not less than 0.8 N / 15 mm width and not more than 15.0 N / 15 mm width. It is preferable.

  Since the composite film for laminating according to the first aspect of the present invention includes a polyamide resin layer as an outer layer, it can have pinhole resistance and deep drawability. Moreover, since the cyclic polyolefin resin layer is provided as the intermediate layer, the composite film can be prevented from curling and the waist can be imparted to the composite film. Thereby, workability | operativity which laminates a composite film on another film becomes favorable (lamination suitability becomes favorable). Moreover, since the heat seal layer is provided as the inner layer, heat sealability can be imparted to the composite film. Moreover, bending resistance can be provided to a composite film by making a cyclic polyolefin resin layer into predetermined thickness. Thereby, the number of pinholes can be reduced to 20 or less in the gelboflex test under the above conditions.

  The laminate composite film of the present invention is composed of an inner layer, an intermediate layer, and an outer layer. The “outer layer” refers to a layer on the side of the laminate surface when the composite film of the present invention is used as a film for laminating. The “inner layer” refers to a layer on the side that becomes the heat seal surface opposite to the laminate surface. The “intermediate layer” refers to a layer sandwiched between the inner layer and the outer layer.

<Inner layer>
The inner layer includes at least one heat seal layer, and the material constituting the heat seal layer is not particularly limited as long as heat sealability can be imparted. For example, low density polyethylene (LDPE), linear low Density polyethylene (LLDPE), polypropylene (PP), ethylene-vinyl acetate copolymer (EVA), ethylene-acrylic acid copolymer (EAA), ethylene-ethyl acrylate copolymer (EEA), ethylene-methacrylic acid copolymer Polymer (EMAA), ethylene-methyl methacrylate copolymer (EMMA), ethylene-methyl acrylate copolymer (EMA), ethylene-acrylic acid copolymer (EAA) ionomer, and ethylene-methacrylic acid copolymer At least one selected from the group consisting of ionomers of polymers (EMAA) It is preferably composed, among this, it is more preferably composed of low density polyethylene (LDPE) and / or a linear low density polyethylene (LLDPE).

  The lower limit of the thickness of the heat seal layer is preferably 5 μm or more, more preferably 7 μm or more, and even more preferably 10 μm or more. Further, the upper limit value of the thickness of the heat seal resin layer is preferably 100 μm or less, more preferably 70 μm or less, and further preferably 50 μm or less. By setting the lower limit value to 5 μm or more, good heat sealability can be maintained, and by setting the upper limit value to 100 μm or less, it is possible to obtain a film with good transparency without unnecessarily thickening the film. It is.

  In the present invention, an easy peel property may be imparted to the heat seal layer, and the easy peel strength is preferably 0.8 N / 15 mm width or more and 15.0 N / 15 mm width or less at 25 ° C. The easy peel may be any of a cohesive failure type, a delamination type, and an interfacial peeling type.

  In the case of the cohesive failure type, at least one type is selected from the resins listed as the material constituting the heat seal layer (resin A), and any one type is selected from polypropylene or polybutylene (resin B). It is obtained by blending these two kinds of resins.

  In the case of resin A, the lower limit of the blend ratio is 40% or more, preferably 45% or more, more preferably 50% or more, and the upper limit is 80% or less, preferably 75% or less, more preferably 70% or less. In the case of resin B, the lower limit is 20% or more, preferably 25% or more, more preferably 30% or more, and the upper limit is 60% or less, preferably 55% or less, more preferably 50% or less. By adjusting the blend ratio to the above range, good heat sealability can be maintained and an appropriate easy peel strength can be obtained.

  In the case of delamination type easy peel, it is possible to peel between the seal layer and the layer adjacent to the seal layer by arranging the resin described below in the seal layer and the layer adjacent to the seal layer. is there. Among the resins used for the sealing layer, polyethylene is preferably used, and among them, linear low density polyethylene and low density polyethylene are preferably used. On the other hand, as the resin disposed in the layer adjacent to the seal layer, polypropylene of 50% by mass to 95% by mass and 5% by mass based on the total mass of the layer adjacent to the seal layer (100% by mass) The blend resin of ethylene-alpha olefin copolymer of 50 mass% or less can be used. The polypropylene constituting the layer adjacent to the seal layer may be a random copolymer with ethylene. When a random copolymer with ethylene is used, the sealing property with the sealing layer can be improved, and the transparency of the resulting film can be further improved. As the ethylene-α-olefin copolymer, those using propylene and butene-1 as the α-olefin are preferable, and those having a specific gravity of 0.85 or more and 0.90 or less are preferable.

<Intermediate layer>
The intermediate layer in the composite film of the present invention includes at least one cyclic polyolefin resin layer, and the lower limit of the thickness of the cyclic polyolefin resin layer is 3% or more, preferably 5% or more, more preferably the total thickness. The upper limit is less than 20%, preferably less than 17%, more preferably less than 15%. The thickness of the cyclic polyolefin resin layer in the composite film of the present invention is less than 30 μm, preferably less than 25 μm, and more preferably less than 20 μm.

  By making the thickness of the cyclic polyolefin resin layer 3% or more with respect to the total thickness of the composite film for laminating, curling the composite film to the heat seal layer side can be suppressed, and hardness (waist) is imparted to the film. Therefore, the laminate suitability is improved. In addition, when the thickness is less than 20% and less than 30 μm, the film does not become too hard and can be provided with bending resistance, and the expensive cyclic polyolefin resin layer is not unnecessarily thickened. Can be suppressed.

  Examples of the cyclic polyolefin resin include a cycloolefin polymer (COP) obtained by ring-opening polymerization of a cyclic olefin, or a cycloolefin copolymer (COC) obtained by copolymerizing an α olefin and a cyclic olefin. Note that COC is preferable in terms of cost and various Tg products. As COP, for example, ZEONOR 750R (manufactured by Nippon Zeon Co., Ltd., Tg 70 ° C.) can be used. As the COC, for example, Apel (Mitsui Chemicals, Tg 80 ° C.) or the like can be used.

  In the conventional composite film, for example, after the polyamide resin layer and the polyethylene layer are formed by coextrusion, the polyethylene layer is crystallized, and the polyethylene layer shrinks over time. The composite film was curled to the polyethylene layer side due to the difference in shrinkage between the polyethylene layer and the polyethylene layer. On the other hand, in the present invention, since the cyclic polyolefin resin is amorphous, the cyclic polyolefin resin layer does not shrink due to crystallization after film formation. Therefore, since the difference in shrinkage between the polyamide resin layer is small, curling of the composite film can be prevented.

  The cyclic polyolefin resin layer is a low density polyethylene (LDPE) and / or a linear low density polyethylene of 5% by mass or more and 50% by mass or less based on the mass of the entire resin constituting the cyclic polyolefin resin layer (100% by mass). (LLDPE) can be included. By setting the content of LDPE and / or LLDPE to 5% or more, it is possible to suppress the occurrence of butts, gels, and fish eyes during film formation, and to impart flexibility to the film. In addition, by controlling the content to 50% or less, curling of the composite film to the heat seal layer side can be suppressed and hardness (waist) can be imparted to the film. .

  The cyclic polyolefin resin used for the cyclic polyolefin resin layer of the present invention has a lower limit of glass transition temperature of 60 ° C or higher, preferably 65 ° C or higher, more preferably 70 ° C or higher, and an upper limit of 140 ° C or lower, preferably 135 ° C. Below, it is 130 degrees C or less more preferably. By setting the glass transition temperature to 60 ° C. or higher, the film is not softened when the temperature is high when the film is stored, and the film wound on the paper tube can be prevented from being squeezed by the softening of the film. In addition, by setting the glass transition temperature to 140 ° C. or lower, it is not necessary to set a high extrusion temperature during film formation. , Gels and the like can be suppressed.

  Moreover, the cyclic polyolefin resin layer of this invention may be divided | segmented and arrange | positioned into two or more cyclic polyolefin resin layers through the polyolefin resin layer. Thereby, bending resistance can be provided.

<Outer layer>
The outer layer of the present invention includes at least one polyamide resin layer (PA layer) in order to impart pinhole resistance and deep drawability.

  The polyamide resin constituting the PA layer is not particularly limited, but it is preferable to use a polyamide resin having a main component (50 mol% or more) of a lactam having three or more members, a polymerizable ω-amino acid, a diamine and a dicarboxylic acid. The polyamide resin may be a copolymer of a polyamide component and other components (for example, a ω-amino acid, a diamine and a dicarboxylic acid as main components (50 mol% or more)). Is preferably 80 mol% or more, more preferably 85 mol% or more, and even more preferably 90 mol% or more. The upper limit value of the polyamide component is 99 mol% or less, which is the upper limit value of a typical copolymer.

  Further, the polyamide resin may be a polymer blend. In that case, the polyamide resin is preferably 70% by mass or more and 75% by mass or more based on the mass of the whole polymer blend (100% by mass). Is more preferably 80% by mass or more, and the upper limit value of the polyamide resin is 99% by mass or less which is the upper limit value of a typical polymer blend.

  Examples of the lactam having 3 or more members include ε-caprolactam, ω-enantolactam, ω-laurolactam, α-pyrrolidone and the like. Examples of the polymerizable ω-amino acid include ω-aminocaproic acid, ω-aminoheptanoic acid, ω-aminononanoic acid, ω-aminoundecanoic acid, and ω-aminododecanoic acid. Examples of the diamine include tetramethylene diamine, hexamethylene diamine, heptamethylene diamine, octamethylene diamine, nonamethylene diamine, decamethylene diamine, undecamethylene diamine, dodecamethylene diamine, 2,2,4-trimethylhexamethylene diamine, Aliphatic amines such as 2,4,4-trimethylhexamethylenediamine, 1,3 / 1,4-bis (aminomethyl) cyclohexane, isophoronediamine, piperazine, bis (4-aminocyclohexyl) methane, 2,2-bis Examples include alicyclic diamines such as-(4'-aminocyclohexyl) propane, and aromatic diamines such as metaxylylenediamine and paraxylylenediamine.

  Examples of the dicarboxylic acid include glutaric acid, adipic acid, pimelic acid, suberic acid, azelaic acid, sebacic acid, nonanedioic acid, decanedioic acid, undecanedioic acid, dodecanedioic acid and other aliphatic dicarboxylic acids, hexahydroterephthalic acid, Hexahydroisophthalic acid and other alicyclic carboxylic acids, terephthalic acid, isophthalic acid, naphthalenedicarboxylic acid (1,2-form, 1,3-form, 1,4-form, 1,5-form, 1,6- , 1,7-isomer, 1,8-isomer, 2,3-isomer, 2,6-isomer, 2,7-isomer), and aromatic dicarboxylic acids such as metal-isophthalsulfonic acid.

  In the PA layer, the above-mentioned lactam having three or more members, a polymerizable ω-amino acid, a homopolymer or copolymer of polyamide resin derived from diamine and dicarboxylic acid can be used alone or as a mixture. Specifically, for example, 4 nylon, 6 nylon, 7 nylon, 11 nylon, 12 nylon, 46 nylon, 66 nylon, 69 nylon, 610 nylon, 611 nylon, 6T nylon, 6I nylon, MXD6 nylon, 6-66 Nylon, 6-610 nylon, 6-611 nylon, 6-12 nylon, 6-612 nylon, 6-6T nylon, 6-6I nylon, 6-66-610 nylon, 6-66-12 nylon, 6-66- 612 nylon, 66-6T nylon, 66-6I nylon, 6T-6I nylon, 66-6T-6I nylon and the like.

  Among these, as the polyamide constituting the PA layer, 6 nylon or 6-66 nylon is preferably used from the viewpoint of pinhole resistance. Further, two or more PA layers can be provided, and in this case, each layer may be formed of different types of polyamides.

  The thickness of the PA layer is not particularly limited, but the lower limit is preferably 5% or more, more preferably 8% or more, and further preferably 10% or more of the total thickness of the composite film. The upper limit is preferably 60% or less, more preferably 50% or less, and even more preferably 40% or less. When the lower limit of the thickness of the PA layer is 5% or more of the film thickness, good pinhole resistance can be obtained, and when the upper limit is 60% or less, the deep drawability can be maintained well.

(Ethylene-vinyl acetate copolymer saponified resin layer (EVOH layer))
In the outer layer of the present invention, at least one EVOH layer may be disposed outside or inside the PA layer for the purpose of imparting oxygen barrier properties. The ethylene content of the ethylene-vinyl acetate copolymer saponified resin (EVOH) in the EVOH layer is not particularly limited, but from the viewpoint of film formation stability, the lower limit is preferably 32 mol% or more, and 38 mol. % Is more preferable, and the upper limit is preferably 47 mol% or less, more preferably 44 mol% or less.

  The saponification degree of EVOH is preferably 90 mol% or more, more preferably 95 mol% or more. By maintaining the ethylene content and saponification degree of EVOH within the above ranges, the coextrudability of the composite film of the present invention and the strength of the composite film can be improved.

  The lower limit of the thickness of the EVOH layer is preferably 3 μm or more, more preferably 5 μm or more, and further preferably 7 μm or more. The upper limit is preferably 50 μm or less, more preferably 40 μm or less, and even more preferably 30 μm or less. By setting the lower limit of the thickness of the EVOH layer to 3 μm or more, sufficient oxygen barrier properties can be imparted, and stable film formation becomes possible. Further, by setting the upper limit of the EVOH layer to 50 μm or less, good deep drawability can be obtained, and pinhole resistance can also be obtained.

<Adhesive layer>
An adhesive layer can be provided as needed for the purpose of increasing the delamination strength of each layer. There may be one or more adhesive layers. Adhesive resins that can be used as the adhesive layer include polyethylene (PE) such as low density polyethylene (LDPE), linear low density polyethylene (LLDPE), medium density polyethylene (MDPE), and high density polyethylene (HDPE), polypropylene ( Olefin resin such as PP), ethylene-vinyl acetate copolymer (EVA), ethylene-methyl methacrylate copolymer (EMMA), ethylene-ethyl acrylate copolymer (EEA), ethylene-methyl acrylate copolymer ( EMA), ethylene-ethyl acrylate-maleic anhydride copolymer (E-EA-MAH), ethylene-acrylic acid copolymer (EAA), ethylene-methacrylic acid copolymer (EMMA), ethylene ionomer (ION) ) And other ethylene copolymer resins, etc. Modified polyolefin resin, for example, ethylene-vinyl acetate copolymer or ethylene elastomer, monobasic unsaturated fatty acid such as acrylic acid or methacrylic acid, or dibasic fatty acid such as maleic acid, fumaric acid or itaconic acid The thing which chemically couple | bonded the anhydride of this can be illustrated. Among them, it is preferable to use an adhesive resin based on polyethylene.

  When the adhesive layer is provided, the lower limit of the thickness of the adhesive layer is preferably 3 μm or more, more preferably 5 μm or more, and even more preferably 8 μm or more from the viewpoints of workability, economy, and handling properties. The upper limit is not particularly limited, but is preferably 30 μm or less, more preferably 25 μm or less, and further preferably 20 μm or less. When the thickness of the adhesive layer is 3 μm or more, the delamination strength can be improved. If the adhesive layer is too thick, the transparency is deteriorated and the total thickness of the film is increased, and the manufacturing cost is increased, so the upper limit is desirably 30 μm or less.

<Layer structure of composite film for laminating>
The layer structure of the composite film for laminating according to the present invention includes at least one polyamide resin layer as an outer layer, at least one cyclic polyolefin resin layer as an intermediate layer, and at least one heat seal layer as an inner layer. If it is, it will not be specifically limited.

  Further, the total thickness of the composite film for laminating is preferably 40 μm or more and 200 μm or less. As described above, the thickness of the cyclic polyolefin resin layer is 3% or more and less than 20% of the total thickness of the composite film. Yes, and less than 30 μm.

For example, PA layer (A), EVOH layer (B), cyclic polyolefin resin, COC layer (C), heat seal layer, polyethylene resin layer (D), easy peel layer (E), polypropylene resin layer (F) And the adhesive layer (G), the following layer structure can be formed. Among these, a preferable layer configuration is the following (2), (3), (4), (5), (19) or (20), and a more preferable layer configuration is (19) or (20).
(1) A / G / C / D
(2) A / B / G / C / D
(3) B / A / G / C / D
(4) A / G / B / G / C / D
(5) B / G / A / G / C / D
(6) A / G / C / D / E
(7) A / B / G / C / D / E
(8) B / A / G / C / D / E
(9) A / G / D / C / D
(10) A / B / D / G / C / D
(11) B / A / G / D / C / D
(12) A / G / C / G / F
(13) A / B / G / C / G / F
(14) B / A / G / C / G / F
(15) A / G / C / D / C / D
(16) A / B / G / C / D / C / D
(17) B / A / G / C / D / C / D
(18) A / G / D / C / D
(19) A / B / G / D / C / D
(20) B / A / G / D / C / D

  For example, in (19) above, the outer layer corresponds to “A / B”, the intermediate layer corresponds to “G / D / C”, and the inner layer corresponds to “D”. However, this distinction is not strict, the outer layer may be “A / B / G”, the intermediate layer may be “D / C”, the inner layer may be “D”, or the outer layer may be “A / B”. / B / G / D ”, the intermediate layer may be“ C ”, and the inner layer may be“ D ”.

  “PA layer (A)” and “EVOH layer (B)” are included in the outer layer, “cyclic polyolefin resin layer (C)” is included in the intermediate layer, and “heat seal layers (D, E, F)” are included in the inner layer. "Is included, it is not particularly necessary to distinguish the boundaries between the layers. The adhesive layer may be included in any of the outer layer, the intermediate layer, and the inner layer, and the heat seal layer may be included in the outer layer and the intermediate layer. Moreover, it is necessary to make an innermost layer into a heat seal layer from the point which provides a heat seal property to a composite film.

<Method for producing composite film for laminating>
The laminate composite film of the present invention can be produced using a known method. For example, an extrusion lamination method, a coextrusion inflation method, a coextrusion T die method, and the like can be used, and it is particularly preferable to use a method in which the extrusion lamination method and the coextrusion T die method are combined.

Examples of the present invention will be described below, but the present invention is not limited thereto.
<Example 1>
(Production of composite film for lamination)
A composite film for laminating of the present invention having the following layer constitution was produced by the coextrusion T-die method.
Ny1 (25 μm) / adhesive resin (15 μm) / COC1 (15 μm) / LLDPE1 (25 μm)
Here, “Ny1” is Novamid 6Ny manufactured by Mitsubishi Engineering Plastics. “Adhesive resin” is Admer (based on LLDPE) manufactured by Mitsui Chemicals. “COC1” is manufactured by Mitsui Chemicals, Inc. (Tg = 80 ° C.). “LLDPE1” is Novatec LL made by Nippon Polyethylene.

<Example 2>
A composite film for laminating of the present invention having the following layer constitution was produced by the coextrusion T-die method.
Ny1 (10 μm) / EVOH (10 μm) / adhesive resin (10 μm) / COC1 (5 μm) / LLDPE1 (15 μm)
Here, “EVOH” is Soarnol (44 mol type) manufactured by Nippon Synthetic Chemical Industry.

<Example 3>
A composite film for laminating of the present invention having the following layer constitution was produced by the coextrusion T-die method.
EVOH (15 μm) / Ny1 (15 μm) / Adhesive resin (15 μm) / COC1 (15 μm) / LLDPE1 (10 μm) / EP1 (15 μm)
Here, as “EP1,” 65% of Novatec EVA (8 mol% vinyl acetate) manufactured by Nippon Polyethylene Co., Ltd. and 35% of Novatec PP (random copolymer) manufactured by Nippon Polypro Co., Ltd. were used.

<Example 4>
A composite film for laminating of the present invention having the following layer constitution was produced by the coextrusion T-die method.
Ny1 (10 μm) / EVOH (10 μm) / adhesive resin (5 μm) / LLDPE1 (5 μm) / COC1 (5 μm) / LLDPE1 (5 μm)

<Example 5>
A composite film for laminating of the present invention having the following layer constitution was produced by the coextrusion T-die method.
Ny1 (25 μm) / adhesive resin (20 μm) / COC2 (15 μm) / LLDPE1 (20 μm)
Here, “COC2” is a blend of 80% of Apel (Tg = 80 ° C.) manufactured by Mitsui Chemicals, and 20% of Novatec LL manufactured by Nippon Polyethylene.
<Example 6>
A composite film for laminating of the present invention having the following layer constitution was produced by the coextrusion T-die method.
Ny1 (125 μm) / adhesive resin (20 μm) / COC2 (25 μm) / LLDPE1 (20 μm)

<Comparative Example 1>
A composite film for laminating having the following layer structure was produced by the coextrusion T-die method.
Ny1 (10 μm) / adhesive resin (5 μm) / COC1 (50 μm) / LLDPE1 (5 μm)

<Comparative example 2>
A composite film for laminating having the following layer structure was produced by the coextrusion T-die method.
Ny1 (10 μm) / EVOH (10 μm) / adhesive resin (10 μm) / COC1 (1 μm) / LLDPE1 (19 μm)

<Evaluation method>
(Curl property of film)
When a 100 mm square film is allowed to stand under the condition of 23 ° C. × 50% RH and the film is curled due to curling of the film, the film diameter is less than 10 mm “X”, and 10 mm or more but less than 20 mm is “△”. , 20 mm or more or not rounded was evaluated as “◯”. Five samples were measured for one week after film formation, and the average value was determined.

(Gelbo flex test)
Under a condition of 5 ° C. and 40% RH, using a Gelboflex tester manufactured by Tester Sangyo Co., Ltd., 500 cycles of bending test were continuously performed on five samples at a rate of 40 cycles per minute, The average number of pinholes was evaluated as “◯” when 20 or less, and “×” when 21 or more.

(Easy peel strength)
Using a deep-drawing packaging machine (FV6300, manufactured by Omori Machinery Co., Ltd.), heat-sealing the film with dry lamination of ONy (15 μm) and LLDPE (50 μm) under the conditions of a sealing temperature of 140 ° C. and a sealing time of 2 seconds. The maximum load when it was cut into strips with a width of 15 mm and peeled at a speed of 200 mm / min with a tensile tester was defined as easy peel strength.

  From Table 1, in the composite films for laminates of Examples 1 to 6, it was found that the evaluation of curl properties and gelboflex properties of the films was good. On the other hand, in Comparative Example 1, since the thickness of the cyclic polyolefin resin layer (COC1) was too thick as 50 μm, the film was hard and the bending resistance was poor (the result of the gelboflex test was bad). In Comparative Example 2, since the thickness of the cyclic polyolefin resin layer (COC1) was too thin, 1 μm, it was not possible to prevent the film from curling.

  While the present invention has been described in connection with embodiments that are presently the most practical and preferred, the present invention is not limited to the embodiments disclosed herein. However, the present invention can be changed as appropriate without departing from the spirit or concept of the invention that can be read from the claims and the entire specification, and a composite film for laminating with such a change is also included in the technical scope of the present invention. It must be understood as a thing.

Claims (5)

A composite film consisting of an outer layer, an intermediate layer, and an inner layer,
The outer layer includes at least one polyamide resin layer;
The intermediate layer includes at least one cyclic polyolefin resin layer;
The inner layer includes at least one heat seal layer;
The thickness of the cyclic polyolefin resin layer is 3% or more and less than 20% of the total thickness of the composite film, and the thickness of the cyclic polyolefin resin layer is less than 30 μm,
The number of pinholes when a bending test of 500 cycles is continuously performed at a rate of 40 cycles per minute using a gelbo flex tester under conditions of 5 ° C. and 40% RH is 20 or less. A composite film for laminating, characterized in that. The heat seal layer is composed of low density polyethylene (LDPE), linear low density polyethylene (LLDPE), ethylene-vinyl acetate copolymer (EVA), ethylene-acrylic acid copolymer (EAA), ethylene-ethyl acrylate. Copolymer (EEA), ethylene-methacrylic acid copolymer (EMAA), ethylene-methyl methacrylate copolymer (EMMA), ethylene-methyl acrylate copolymer (EMA), ethylene-acrylic acid copolymer ( The composite film for laminating according to claim 1, comprising at least one selected from the group consisting of an ionomer of EAA) and an ionomer of ethylene-methacrylic acid copolymer (EMAA). The composite film for laminate according to claim 1 or 2, wherein the cyclic polyolefin resin constituting the cyclic polyolefin resin layer has a glass transition point (Tg) of 60 ° C or higher and 140 ° C or lower. The cyclic polyolefin resin layer is composed of 100% by mass of the entire resin constituting the cyclic polyolefin resin layer, and is 5% by mass or more and 50% by mass or less of low density polyethylene (LDPE) and / or linear low density polyethylene (LLDPE). The composite film for laminate according to claim 1, comprising: The laminate according to any one of claims 1 to 4, wherein the heat seal layer has an easy peel property, and an easy peel strength is 25 ° C and not less than 0.8 N / 15 mm width and not more than 15.0 N / 15 mm width. Composite film.