WO2019065147A1

WO2019065147A1 - Multilayer film

Info

Publication number: WO2019065147A1
Application number: PCT/JP2018/033053
Authority: WO
Inventors: 山崎　敦史; 小林　正典
Original assignee: 東洋紡株式会社
Priority date: 2017-09-29
Filing date: 2018-09-06
Publication date: 2019-04-04
Also published as: TWI782095B; JPWO2019065147A1; TW201917019A; JP7218577B2

Abstract

[Problem] The present invention addresses the problem of providing a multilayer film which is formed of a polyamide base film that has good barrier properties and good water-resistant adhesiveness even in a high-temperature high-humidity environment, and which is easily producible, while having excellent economic efficiency. [Solution] A multilayer film which has a cover layer on at least one surface of a polyamide base film, and wherein: the cover layer is formed from a resin composition for cover layers, which contains a polyester resin as a constituent; an inorganic thin film layer is arranged on the cover layer; and a protective layer that contains a urethane resin having a meta-xylylene group is arranged on the inorganic thin film layer. This multilayer film is characterized in that the protective layer of this multilayer film has a surface hardness of from 220 N/mm2 to 310 N/mm2.

Description

Laminated film

The present invention relates to a laminated film used in the field of packaging of food, pharmaceuticals, industrial products and the like. Specifically, it is a laminated film provided with a base film, a covering layer, an inorganic thin film layer, and a protective layer, and capable of expressing good gas barrier properties and water adhesion (lamination strength) even in a high temperature and high humidity environment. About.

Packaging materials used for food, medicines, etc. have the property of blocking gas such as oxygen and water vapor, that is, gas barrier property, for suppressing oxidation of protein and oil, maintaining taste and freshness of medicine, maintaining efficacy of medicine. It has been demanded. In addition, it is also important that the barrier performance and adhesion performance do not deteriorate during long distance transportation or storage under high temperature and high humidity environment due to the recent domestic climate change (temperature rise and heavy rain) and the expansion of demand at home and abroad. It has become.

Conventionally, in food applications that require blocking of various gases such as water vapor and oxygen, a metal thin film of aluminum or the like, an inorganic oxide of inorganic oxide such as silicon oxide or aluminum oxide, etc. on the surface of a substrate film of plastic A gas barrier laminate in which a thin film is formed is generally used. Among them, those having a thin film (inorganic thin film layer) of an inorganic oxide such as silicon oxide, aluminum oxide, or a mixture thereof are widely used because they are transparent and the contents can be confirmed.

However, since the above-mentioned gas barrier laminate is likely to be locally heated to a high temperature in the forming step, the substrate may be damaged, or decomposition or degassing may occur in a low molecular weight portion or a portion of an additive such as a plasticizer. Due to this, defects, pinholes and the like may be generated in the inorganic thin film layer, and the gas barrier properties may be lowered. Furthermore, there is also a problem that the inorganic thin film layer is cracked and cracks occur during post-processing of the packaging material such as printing, laminating, bag-making, and the gas barrier property is lowered.

Attempts have been made to further provide a protective layer having gas barrier properties on the inorganic thin film layer as a method of improving the defects of the gas barrier laminate having the inorganic thin film layer formed thereon. For example, there is a method of laminating a gas barrier resin composition composed of an ethylene-vinyl alcohol copolymer, an inorganic layered compound and an additive (for example, Patent Document 1). In this method, the defects and the gas barrier properties of the inorganic thin film layer are greatly improved.

However, in the above method, interlayer adhesion is reduced due to the lack of water resistance of the protective layer. The film with reduced interlayer adhesion has a problem that peeling occurs due to bending load and the content of the liquid, the barrier property is deteriorated, and the content leaks out.

To solve these problems, a water-soluble polymer and an inorganic layered compound and a metal alkoxide or a hydrolyzate thereof are coated on the inorganic thin film layer, and the inorganic layer compound containing the inorganic layered compound on the inorganic thin film layer and the water A method of forming a complex with a sex polymer has been proposed (for example, Patent Document 2). According to this method, in addition to excellent barrier properties, it also exhibits excellent properties with respect to water resistance, but the stability of the liquid to be provided for coating is low, so the start and end times of coating (for example, industrial distribution) In the case of a roll film, the characteristics differ between the roll outer peripheral portion and the inner peripheral portion), or the characteristics differ due to slight differences in drying and heat treatment in the film width direction, and the quality differs according to the production environment Had a big problem. Furthermore, since the film coated by the sol-gel method is poor in flexibility, it is pointed out that pinholes and cracks are easily generated when bending or impact is applied to the film, and the gas barrier properties may be lowered. .

Under such background, there is a demand for improvement in which a resin layer can be formed on an inorganic thin film layer by a coating method that does not involve a sol-gel reaction or the like, that is, a coating method that mainly includes a resin and involves a crosslinking reaction at the time of coating. The As a gas barrier laminate having such an improvement, a gas barrier laminate (for example, Patent Document 3) in which a barrier resin containing a silane coupling agent is coated on an inorganic thin film (for example, Patent Document 3), and a metaxylylene group-containing polyurethane on an inorganic thin film Coated laminate (
For example, Patent Document 4) can be mentioned.

However, even in the method described above, when the substrate is a polyamide film, the substrate absorbs moisture and the film stretches when exposed to a high temperature and high humidity environment, so the substrate and the covering layer, the inorganic thin film layer or the barrier A shear stress acts on the interface of the protective layer, which causes a decrease in barrier performance and a decrease in adhesion.

In the above-mentioned patent documents 3, although improvement in barrier property before and after manual massage is examined and good results are obtained, examination about performance under wet heat environment was not examined. Moreover, in patent document 4, although the humidity dependence of oxygen permeability was examined and each showed a favorable value, it was not similarly examined about the performance under wet heat environment.

Patent No. 5434341 gazette JP 2000-43182 A Patent No. 3441594 Patent No. 4524463

Even with any of the above-mentioned methods, a gas barrier film comprising a polyamide base film which is excellent in production stability and economy at the time of production and has excellent barrier properties and water-resistant adhesion even in a high temperature and high humidity environment has not been obtained. It was the present condition. An object of the present invention is to provide a gas barrier film comprising a polyamide base film which is excellent in production stability and economy at the time of production and has good barrier properties and water-resistant adhesion even in a high temperature and high humidity environment. is there.

As a result of intensive investigations to solve the above problems, the present inventors have found that by providing a specific coating layer, an inorganic thin film layer and a protective layer on at least one side of a substrate film, good barrier property and water-resistant adhesion And found a laminated film having sufficient performance even in a high temperature and high humidity environment, and completed the present invention.

The laminated film of the present invention which solves the above-mentioned subject has the following modes.

(1) A coating layer is provided on at least one surface of the polyamide base film, and the coating layer is made of a resin composition for a coating layer containing a polyester resin as a component, and an inorganic thin film layer is provided on the coating layer A laminated film having a protective layer containing a urethane resin having a metaxylylene group on the inorganic thin film layer, wherein the surface hardness of the protective layer of the laminated film is 220 to 310 N / mm ² .

(2) The laminated film according to (1), wherein the polyester resin contained in the covering layer is an acrylic graft polyester resin.

(3) The laminated film according to any one of (1) and (2), wherein the inorganic thin film layer is a layer composed of a composite oxide of silicon oxide and aluminum oxide.

The laminated film provided with the coating layer, the inorganic thin film layer and the protective layer of the present invention has gas barrier properties and excellent water-resistant adhesion, so peeling does not occur even by bending load and aqueous contents, and barrier properties are obtained. There is no problem of deterioration or leakage of contents. In addition, since the laminated film of the present invention is designed as a protective layer of surface hardness which can follow the expansion and contraction of the polyamide base film in a high temperature and high humidity environment, the inorganic layer by the shear stress accompanying the expansion and contraction of the base material It is possible to prevent damage to the surface and reduction in adhesion strength due to delamination. Moreover, since the laminated film of the present invention has few processing steps and can be easily manufactured, it is excellent in both economical efficiency and production stability, and a gas barrier film of homogeneous characteristics can be provided.

The laminated film of the present invention has a coating layer on at least one surface of a polyamide base film, and the coating layer is made of a resin composition for a coating layer containing a polyester resin as a component, and an inorganic thin film layer is formed on the coating layer. And a protective layer containing a urethane resin on the inorganic thin film layer, and the surface hardness of the protective layer of the laminated film is 220 to 310 N / mm ² .

Hereinafter, a base film and each layer laminated | stacked on this are demonstrated in order.

[Base film]
As a substrate film used in the present invention, a polyamide substrate film (hereinafter sometimes referred to as “substrate film”) represented by nylon 4 • 6, nylon 6, nylon 6 • 6, nylon 12 etc. is used . The polyamide substrate film is superior to other resin substrate films in terms of the resistance to bag-proofing and pinholes. Examples of the polyamide resin used in the present invention include nylon 6 whose main raw material is ε-caprolactam. Other polyamide resins include polyamide resins obtained by polycondensation of a three-membered or more ring lactam, an ω-amino acid, a dibasic acid and a diamine or the like. Specifically, as lactams, in addition to ε-caprolactam shown above, enanthlactam, capryl lactam, lauryl lactam, as ω-amino acids, 6-amino caproic acid, 7-amino heptanoic acid, 9- Aminononanoic acid and 1,1-aminoundecanoic acid can be mentioned. Also, as dibasic acids, adipic acid, glutaric acid, pimelic acid, suberic acid, azelaic acid, sebacic acid, undecanedioic acid, dodecadioic acid, hexadecadioic acid, eicosandioic acid, eicosadiene dioic acid, 2 And 2,4-trimethyladipic acid, terephthalic acid, isophthalic acid, 2,6-naphthalenedicarboxylic acid and xylylenedicarboxylic acid. Furthermore, as diamines, ethylenediamine, trimethylenediamine, tetramethylenediamine, hexamethylenediamine, pentamethylenediamine, undecamethylenediamine, 2,2,4 (or 2,4,4) -trimethylhexamethylenediamine, cyclohexane Diamine, bis- (4,4'-aminocyclohexyl) methane, metaxylylene diamine and the like can be mentioned. And polymers obtained by polycondensing these or copolymers thereof, such as nylon 6, 7, 11, 12, 6.6, 6.9, 6.11, 6.12, 6T, 6I, MXD 6 (Meta-xylene dipanamide 6), 6 / 6.6, 6/12, 6/6 T, 6/6 I, 6 / MXD6, etc. can be used. The above-described polyamide resins can be used alone or in combination of two or more.

As the substrate film, any film thickness can be used depending on the desired purpose and application such as mechanical strength and transparency, and the film thickness is not particularly limited, but usually 5 to 100 μm. Is recommended, and when used as a packaging material, 8 to 60 μm is desirable. The transparency of the substrate film is not particularly limited, but when it is used as a packaging material for which transparency is required, one having a light transmittance of 50% or more is desirable.

The polyamide substrate film is preferably a stretched film stretched in at least one direction of the longitudinal direction or the transverse direction from the viewpoint of imparting mechanical strength, and biaxially stretched in the two directions of the longitudinal direction and the transverse direction It is more preferable that it is a stretched film. As a stretching method of the biaxially stretched film, any stretching method such as simultaneous biaxial stretching or sequential biaxial stretching can be adopted. As a preferable mode of the stretching method in the sequential biaxial stretching, the unstretched film is longitudinally stretched at a stretching ratio of 3.0 times to 4.5 times in the longitudinal direction at a temperature of 70 ° C. to 90 ° C. by a roll stretching machine. It is drawn and then drawn at a draw ratio of 3.5 times to 5.5 times at a temperature of 110 ° C. to 140 ° C. by a tenter-type drawing machine, and a method of heat treatment at a temperature of 180 ° C. to 230 ° C. after drawing is mentioned be able to. When the in-line coating method is employed as a step of forming a coating layer described later, the film after being stretched in the longitudinal direction is coated with the coating layer in the step of the sequential biaxial stretching described above, and then continuously. The film can be directed to a tenter-type stretcher for lateral stretching and heat treatment.

The base film may be a single layer type film made of a polyamide resin, or may be a laminated type film in which a polyamide resin layer and another plastic film (which may be two or more types) are laminated. . As long as the polyamide resin layer is present, the number of laminations, the lamination method, etc. are not particularly limited as long as there is a polyamide resin layer, and can be arbitrarily selected from known methods according to the purpose.

Further, in the present invention, in order to improve the interlayer adhesion between the inorganic thin film layer and the polyamide substrate, a desired surface treatment layer can be provided in advance, if necessary.
In the present invention, as the above-mentioned surface treatment layer, for example, corona discharge treatment, ozone treatment, low temperature plasma treatment using oxygen gas or nitrogen gas etc., glow discharge treatment, oxidation treatment to be treated using chemical chemicals etc., etc. Pretreatment such as, for example, can be optionally performed to form, for example, a corona treatment layer, an ozone treatment layer, a plasma treatment layer, an oxidation treatment layer, and the like. The above surface pretreatment is carried out as a method for improving the tight adhesion and the like between various resin films and a vapor deposited film of a metal oxide, but as a method for improving the tight adhesion as described above, other methods are also available. For example, a primer coating layer, an undercoat layer, an anchor coating layer, an adhesive layer, a vapor deposition anchor coating layer, etc. are optionally formed in advance on the surfaces of various resin films, and then coated. It can also be a layer.

[Covering layer]
The laminated film of the present invention has a covering layer on at least one side of the polyamide base film. In order to improve the adhesion strength between the base material layer and the inorganic thin film layer by the formation of the covering layer, the use of a polyester resin is preferable in terms of cost and hygiene. Such polyester resins can be obtained by polycondensation of dicarboxylic acids or tricarboxylic acids with glycols. Examples of components used for the polycondensation include acid components such as terephthalic acid, isophthalic acid, adipic acid and trimellitic acid, and glycol components such as ethylene glycol, neopentyl glycol, butanediol and ethylene glycol modified bisphenol A. However, of course, it is not limited to these. Further, it is preferable to use an acrylic graft polyester resin obtained by graft copolymerization of an acrylic monomer as the polyester resin, and from the point that curing of the film proceeds and cohesion can be improved.

In the present invention, the adhesion amount of the coating layer is preferably 0.010 to 0.200 g / m ² . As a result, the covering layer can be uniformly controlled, and as a result, the inorganic thin film layer can be densely deposited. In addition, the cohesion of the inside of the coating layer is improved, and the adhesion between the base film, the coating layer and the inorganic thin film layer is also enhanced, whereby the water-resistant adhesion of the coating layer can be enhanced. Adhesion amount of the coating layer is preferably 0.015 g / m @ 2 or more, more preferably 0.020 g / ^{m 2} or more, more preferably 0.025 g / ^{m 2} or more, preferably 0.190 g / ^{m 2} or less, More preferably, it is 0.180 g / m ² or less, more preferably 0.170 g / m ² or less. When the adhesion amount of the coating layer exceeds 0.200 g / m ² , the cohesion of the inside of the coating layer may be insufficient, and good adhesion may not be exhibited. In addition, since the uniformity of the coating layer is also reduced, defects may occur in the inorganic thin film layer, and the gas barrier properties may be reduced. Moreover, the manufacturing cost is high and it is economically disadvantageous. On the other hand, if the film thickness of the coating layer is less than 0.010 g / m ² , the substrate can not be sufficiently coated, and sufficient gas barrier properties and interlayer adhesion may not be obtained.

If necessary, the resin composition for a coating layer may contain various known inorganic and organic additives such as an antistatic agent, a sliding agent, and an antiblocking agent, as long as the present invention is not impaired. It is also good.

The formation method of a coating layer is not specifically limited, For example, conventionally well-known methods, such as a coating method, are employable. Among the coating methods, the off-line coating method and the in-line coating method can be mentioned as preferable methods. For example, in the case of the in-line coating method performed in the step of producing the base film, the conditions for drying and heat treatment at the time of coating depend on the thickness of the coating and the conditions of the apparatus, It is preferable to dry in the preheating zone or stretching zone of the process, and in such a case, it is preferable to set the temperature to about 50 to 250 ° C. in general.

[Inorganic thin film layer]
In the laminated film of the present invention, an inorganic thin film layer is laminated above the covering layer. The inorganic thin film layer is a thin film made of an inorganic oxide. The material for forming the inorganic thin film layer is not particularly limited as long as it can be made into a thin film, but from the viewpoint of gas barrier properties, silicon oxide (silica), aluminum oxide (alumina), a mixture of silicon oxide and aluminum oxide (complex oxide Etc. are preferably mentioned. In particular, a composite oxide of silicon oxide and aluminum oxide is preferable from the viewpoint of achieving both the flexibility and the compactness of the thin film layer. In this composite oxide, the mixing ratio of silicon oxide and aluminum oxide is preferably in the range of 20 to 70% of Al by mass ratio of metal components. If the Al concentration is less than 20%, the barrier property may be lowered, while if it exceeds 70%, the inorganic thin film layer tends to be hard, and the film is broken during secondary processing such as printing and laminating. As a result, the barrier properties may be reduced. Furthermore, the film can not follow the expansion and contraction of the base film under high temperature and high humidity, and the film may be broken to lower the barrier property. Here, silicon oxide refers to various silicon oxides such as SiO and SiO ₂ or a mixture thereof, and aluminum oxide refers to various aluminum oxides such as AlO and Al ₂ O ₃ or a mixture thereof.

The thickness of the inorganic thin film layer is usually 1 to 100 nm, preferably 5 to 50 nm. If the film thickness of the inorganic thin film layer is less than 1 nm, satisfactory gas barrier properties may not be obtained in some cases. On the other hand, even if it exceeds 100 nm and is excessively thick, the corresponding improvement effect of gas barrier properties is obtained It is rather disadvantageous in terms of bending resistance and manufacturing cost.

There is no restriction | limiting in particular as a method to form an inorganic thin film layer, For example, well-known vapor deposition, such as a physical vapor deposition method (PVD method), such as a vacuum evaporation method, sputtering method, ion plating method, or a chemical vapor deposition method (CVD method) The law may be adopted as appropriate. Hereinafter, a typical method of forming an inorganic thin film layer will be described by taking a silicon oxide / aluminum oxide based thin film as an example. For example, when using a vacuum evaporation method, a mixture of SiO ₂ and Al ₂ O ₃ or a mixture of SiO ₂ and Al is preferably used as an evaporation raw material. Usually, particles are used as the vapor deposition raw material. At this time, the size of each particle is preferably such that the pressure at the time of vapor deposition does not change, and the preferred particle diameter is 1 mm to 5 mm. For heating, a method such as resistance heating, high frequency induction heating, electron beam heating, or laser heating can be adopted. In addition, reactive vapor deposition using means such as introduction of oxygen, nitrogen, hydrogen, argon, carbon dioxide gas, water vapor or the like as a reaction gas, or addition of ozone or ion assist may be employed. Furthermore, film forming conditions can be arbitrarily changed, such as applying a bias to the deposition target (laminated film to be deposited) or heating or cooling the deposition target. Such vapor deposition material, reaction gas, bias of the deposition target, heating / cooling, and the like can be similarly changed also in the case of employing a sputtering method or a CVD method.

[Protective layer]
The laminated film of the present invention has a protective layer on the inorganic thin film layer. The inorganic thin film layer laminated on the plastic film is not a completely dense film, but small defects are scattered. By coating a specific protective layer resin composition to be described later on the inorganic thin film layer to form a protective layer, the resin in the protective layer resin composition penetrates into the defect portion of the inorganic thin film layer, and as a result, The effect of stabilizing the gas barrier properties can be obtained. In addition, the gas barrier performance of the laminated film is also greatly improved by using a material having gas barrier properties for the protective layer itself.

In the present invention, the surface hardness of the protective layer of the laminated film is preferably 220 to 310 N / mm ² . This makes it possible to have the hardness necessary for the development of adhesion and to maintain the performance even when the polyamide base film is expanded and contracted in a high temperature and high humidity environment. Surface hardness, preferably 225N / mm ² or more, more preferably 230N / mm ² or more, more preferably 235N / mm ² or more, preferably 305N / mm ² or less, more preferably 300N / mm ² or less, further Preferably it is 295 N / mm < ² > or less. When the surface hardness of the laminated film exceeds 310 N / mm ² , the surface becomes too hard, so that the adhesive does not penetrate during printing or laminating, and the adhesion is reduced. Moreover, it can not follow expansion and contraction of a base film, and there exists a possibility that the adhesion fall under high temperature and high humidity may fall. On the other hand, if the surface hardness is less than 220 N / mm ² , the cohesion of the protective layer is weak, the protection of the inorganic thin film layer and the complementation of the defective portion become insufficient, and the barrier performance may be deteriorated. Furthermore, the pigment in the ink may be buried to deteriorate the ink transferability (printing appearance). In order to bring the protective layer into the above range of surface hardness, it is preferable to blend the urethane resin described later and, if necessary, a crosslinking agent, etc., and make the adhesion amount within the predetermined range by the method of forming the protective layer described later. .

In the present invention, the adhesion amount of the protective layer is preferably 0.10 to 0.60 g / m ² . Thereby, since a protective layer can be uniformly controlled in coating, it becomes a film with few coat nonuniformity and defects as a result. In addition, the cohesion of the protective layer itself is improved, and the adhesion between the inorganic thin film layer and the protective layer is also strengthened. Deposition amount of the protective layer is preferably from 0.13 g / ^{m 2} or more, more preferably 0.16 g / ^{m 2} or more, further preferably 0.19 g / ^{m 2} or more, preferably 0.57 g / ^{m 2} or less , more preferably 0.54 g / ^{m 2,} more preferably not more than 0.51 g / ^{m 2.} If the adhesion amount of the protective layer exceeds 0.600 g / m ² , the gas barrier properties will be improved, but the cohesion of the inside of the protective layer will be insufficient, and the uniformity of the protective layer will also be reduced. In some cases, defects may occur, or gas barrier properties and adhesion may not be sufficiently exhibited. On the other hand, if the film thickness of the protective layer is less than 0.10 g / m ² , sufficient gas barrier properties and interlayer adhesion may not be obtained.

The laminated film of the present invention contains a urethane resin having a metaxylylene group in the protective layer. The urethane resin has good adhesion to the inorganic thin film layer due to the presence of the urethane bond portion having polarity, and the resin easily penetrates into the defect portion. In addition, since there is a crystal part having high cohesion due to hydrogen bond between urethane bonds, stable gas barrier performance can be obtained. Furthermore, since a highly flexible amorphous portion is also present at the same time, the surface hardness can be made within the predetermined range by controlling the ratio of the amorphous portion to the crystalline portion. The urethane resin is preferably an aqueous dispersion having high polarity and good wettability to the inorganic thin film layer. Moreover, as a hardening type of resin, a thermosetting resin is desirable from a viewpoint of production stability.

(Urethane resin (A))
The urethane resin (A) is obtained by reacting the following polyisocyanate component (B) with the following polyol component (C) by a usual method. Furthermore, the chain is extended by reacting a low molecular weight compound having two or more active hydrogens such as a diol compound (for example, 1,6-hexanediol etc.) or a diamine compound (for example hexamethylene diamine etc.) as a chain extender. Is also possible.

(B) Polyisocyanate Component The polyisocyanate component (B) which can be used for the synthesis of the urethane resin (A) includes aromatic polyisocyanate, alicyclic polyisocyanate, aliphatic polyisocyanate and the like. As a polyisocyanate compound, a diisocyanate compound is usually used.

Examples of aromatic diisocyanates include tolylene diisocyanate (2,4- or 2,6-tolylene diisocyanate or a mixture thereof) (TDI), phenylene diisocyanate (m-, p-phenylene diisocyanate or a mixture thereof), 4,4 '-Diphenyl diisocyanate, 1,5-naphthalene diisocyanate (NDI), diphenylmethane diisocyanate (4,4'-, 2,4'-, or 2,2'-diphenylmethane diisocyanate or mixtures thereof) (MDI) And 4,4'-toluidine diisocyanate (TODI), 4,4'-diphenylether diisocyanate and the like. As the aromatic aliphatic diisocyanate, for example, xylylene diisocyanate (1,3- or 1,4-xylylene diisocyanate or a mixture thereof) (XDI), tetramethyl xylylene diisocyanate (1,3- or 1,4-tetramethylene) Examples include xylylene diisocyanate or a mixture thereof) (TMXDI), ω, ω′-diisocyanate-1,4-diethylbenzene and the like.

Examples of alicyclic diisocyanates include 1,3-cyclopentene diisocyanate, cyclohexane diisocyanate (1,4-cyclohexane diisocyanate, 1,3-cyclohexane diisocyanate), 3-isocyanatomethyl-3,5,5-trimethylcyclohexyl isocyanate (iso Holodiisocyanate, IPDI), methylenebis (cyclohexylisocyanate) (4,4'-, 2,4'- or 2,2'-methylenebis (cyclohexylisocyanate)) (hydrogenated MDI), methylcyclohexane diisocyanate (methyl-2,4-) Cyclohexanediisocyanate, methyl-2,6-cyclohexanediisocyanate), bis (isocyanatomethyl) cyclohexane (1,3- or 1,4-bis (i) Cyanate methyl) cyclohexane or a mixture thereof) (it may be mentioned hydrogenated XDI) and the like.

Examples of aliphatic diisocyanates include trimethylene diisocyanate, 1,2-propylene diisocyanate, butylene diisocyanate (tetramethylene diisocyanate, 1,2-butylene diisocyanate, 2,3-butylene diisocyanate, 1,3-butylene diisocyanate), hexamethylene Diisocyanate, pendamethylene diisocyanate, 2,4,4- or 2,2,4-trimethylhexamethylene diisocyanate, 2,6-diisocyanate methyl carbonate etc. can be mentioned.

(C) Polyol component As the polyol component (especially diol component), although low molecular weight glycol to oligomer can be used, from the viewpoint of gas barrier property, usually alkylene glycol (for example, ethylene glycol, propylene glycol, trimethylene glycol , Linear or branched C2-10 alkylene glycols such as 1,3-butanediol, 1,4-butanediol, pentanediol, hexanediol, neopentyl glycol, heptanediol, octanediol, etc., (poly) oxy Low molecular weight glycols such as C2-4 alkylene glycols (diethylene glycol, triethylene glycol, tetraethylene glycol, dipropylene glycol etc) are used. The preferred glycol component is a C2-8 polyol component [eg, C2-6 alkylene glycol (especially ethylene glycol, 1,2- or 1,3-propylene glycol, 1,4-butanediol, 1,6-hexanediol, 3-methyl-1,5-pentanediol) and the like], di- or trioxy C2-3 alkylene glycol (diethylene glycol, triethylene glycol, dipropylene glycol etc.), particularly preferred diol component is C2-8 alkylene glycol (especially C2) -6 alkylene glycol).

These diol components can be used alone or in combination of two or more. Furthermore, if necessary, aromatic diols (eg, bisphenol A, bishydroxyl terephthalate, catechol, resorcinol, hydroquinone, 1,3- or 1,4-xylylene diol or mixtures thereof, etc.), alicyclic diols (eg, For example, low molecular weight diol components such as hydrogenated bisphenol A, xylylene diol, cyclohexanediol, cyclohexanedimethanol and the like may be used in combination. Furthermore, if necessary, a polyol component having three or more functions, for example, a polyol component such as glycerin, trimethylolethane, trimethylolpropane and the like can be used in combination. The polyol component preferably comprises at least a C2-8 polyol component, in particular a C2-6 alkylene glycol. The proportion of C2-8 polyol component (in particular, C2-6 alkylene glycol) in 100 mass% of the polyol component can be selected from the range of about 50 to 100 mass%, and usually 70 mass% to 100 mass% is preferable, More preferably, it is 80 mass% or more and 100 mass% or less, still more preferably 90 mass% or more and 100 mass% or less.

In the present invention, it is more preferable to use a urethane resin containing an aromatic or araliphatic diisocyanate component as a main component from the viewpoint of gas barrier property improvement by formation of a crystal part derived from a urethane bond. Among these, it is particularly preferable to contain a metaxylylene diisocyanate component. By using the above-mentioned resin, the cohesive force of the urethane bond can be further enhanced by the stacking effect between the aromatic rings, and as a result, good gas barrier properties can be obtained. The proportion of metaxylylene diisocyanate in the urethane resin is preferably in the range of 30 mol% or more (30 to 100 mol%) in 100 mol% of the polyisocyanate component (E). The proportion of the total amount of aromatic or araliphatic diisocyanates is preferably 40 to 100 mol%, more preferably 50 to 100 mol%, and still more preferably 60 to 100 mol%. As such a resin, "Takelac (registered trademark)" series commercially available from Mitsui Chemicals, Inc. can be suitably used. If the proportion of the total amount of metaxylylene diisocyanate is less than 30 mol%, good gas barrier properties may not be obtained.

It is preferable that the said urethane resin has a carboxylic acid group (carboxyl group) from a viewpoint of affinity improvement with an inorganic thin film layer. In order to introduce a carboxylic acid (salt) group into a urethane resin, for example, a polyol compound having a carboxylic acid group such as dimethylol propionic acid or dimethylol butanoic acid may be introduced as a copolymerization component as a polyol component. Moreover, after synthesize | combining a carboxylic acid group containing urethane resin, if it neutralizes with a salt formation agent, the urethane resin of a water dispersion can be obtained. Specific examples of the salt forming agent include ammonia, trimethylamine, triethylamine, triisopropylamine, tri-n-propylamine, trialkylamines such as tri-n-butylamine, N-methylmorpholine, N-ethylmorpholine, etc. And N-dialkylalkanolamines such as -alkyl morpholines, N-dimethyl ethanolamine, N-diethyl ethanolamine and the like. These may be used alone or in combination of two or more.

(Characteristics of urethane resin)
The acid value of the urethane resin is preferably in the range of 10 to 60 mg KOH / g. More preferably, it is in the range of 15 to 55 mg KOH / g, further preferably in the range of 20 to 50 mg KOH / g. When the acid value of the urethane resin is in the above range, the liquid stability is improved when the aqueous dispersion is prepared, and the protective layer can be uniformly deposited on the highly polar inorganic thin film layer, so the coat appearance is It becomes good.

The urethane resin of the present invention preferably has a glass transition temperature (Tg) of 100 ° C. or more, more preferably 110 ° C. or more, and still more preferably 120 ° C. or more, from the viewpoint of barrier property improvement due to cohesion. However, a soft resin having a Tg of 100 ° C. or less, which is excellent in flexibility, may be mixed and used in order to obtain a surface hardness that develops adhesion. In that case, the addition ratio of the soft resin is preferably in the range of 0 to 80%. More preferably, it is in the range of 10 to 70%, further preferably in the range of 20 to 60%. Cohesive force and flexibility can be made to be compatible as an addition ratio is in the said range, and barrier property and adhesiveness become favorable. If the addition ratio exceeds 80%, the film becomes too soft and the barrier performance may be lowered.

In the urethane resin of the present invention, various crosslinking agents may be blended in the range not to impair the gas barrier properties for the purpose of improving the cohesion of the film and the water-resistant adhesiveness. As a crosslinking agent, a silicon type crosslinking agent, an oxazoline compound, a carbodiimide compound, an epoxy compound etc. can be illustrated, for example. Among them, silicon-based crosslinking agents are particularly preferable from the viewpoint of the improvement of water-resistant adhesion to the inorganic thin film layer.

As the silicon-based crosslinking agent, a silane coupling agent is preferable from the viewpoint of crosslinking of an inorganic substance and an organic substance. As a silane coupling agent, a hydrolyzable alkoxysilane compound, for example, a halogen-containing alkoxysilane (2-chloroethyltrimethoxysilane, 2-chloroethyltriethoxysilane, 3-chloropropyltrimethoxysilane, 3-chloropropyltrimethylsilane) Chloro C 2-4 alkyl tri C 1-4 alkoxysilane such as ethoxysilane), alkoxysilane having an epoxy group [2-glycidyl oxyethyl trimethoxysilane, 2-glycidyl oxyethyl triethoxysilane, 3-glycidyloxy propyl trimethoxy Glycidyl oxy C2-4 alkyl tri C 1-4 alkoxy silane such as silane, 3-glycidyloxy propyl triethoxysilane, 3-glycidyloxy propyl methyl dimethoxysilane, 3-glycidyloxy propyl methyl Glycidyl oxy di C 2-4 alkyl di C 1-4 alkoxy silane such as diethoxy silane, 2- (3,4- epoxy cyclohexyl) ethyl trimethoxy silane, 2- (3,4- epoxy cyclohexyl) ethyl triethoxy silane, 3- (Epoxycycloalkyl) C2-4 alkyltri C1-4 alkoxysilane such as (3,4-epoxycyclohexyl) propyltrimethoxysilane], alkoxysilane having an amino group [2-aminoethyltrimethoxysilane, 3-amino] Amino C 2-4 alkyl tri C 1-4 alkoxysilane such as propyltrimethoxysilane, 3-aminopropyl triethoxysilane, etc. Amino di C 2-4 alkyl di C 1 such as 3-aminopropylmethyl dimethoxysilane, 3-aminopropylmethyl diethoxysilane -4 alkoxy silane, 2- [ -(2-Aminoethyl) amino] ethyltrimethoxysilane, 3- [N- (2-aminoethyl) amino] propyltrimethoxysilane, 3- [N- (2-aminoethyl) amino] propyltriethoxysilane, etc. (2-Amino C2-4 alkyl) amino C2-4 alkyltri C1-4 alkoxysilane, 3- [N- (2-aminoethyl) amino] propylmethyldimethoxysilane, 3- [N- (2-aminoethyl) ) Amino] propylmethyldiethoxysilane, etc. (Amino C2-4 alkyl) aminodi C2-4 alkyldi C1-4 alkoxysilane, etc.], Alkoxysilanes having a mercapto group (2-mercaptoethyltrimethoxysilane, 3-mercaptopropyltrityl) Mercapto C2-4 alkyl tri C 1-4 such as methoxysilane, 3-mercaptopropyl triethoxysilane Alkoxysilane, 3-mercaptopropylmethyldimethoxysilane, mercaptodiC2-4alkyldiC1-4alkoxysilane such as 3-mercaptopropylmethyldiethoxysilane, etc., alkoxysilane having vinyl group (vinyltrimethoxysilane, vinyltriethoxysilane) Etc.), alkoxysilanes having an ethylenically unsaturated bond group [2- (meth) acryloxyethyltrimethoxysilane, 2- (meth) acryloxyethyltriethoxysilane, 3- (meth) 3) (Meth) acryloxy C2-4 alkyltri C1-4 alkoxysilane such as acryloxypropyltrimethoxysilane, 3- (meth) acryloxypropyltriethoxysilane, 3- (meth) acryloxypropylmethyldimethoxysilane, 3- (Meta Acryloxy propyl and methyl diethoxy silane (meth) Akurirokishiji C2-4 alkyl di C1-4 alkoxy silane) or the like. These silane coupling agents can be used alone or in combination of two or more. Among these silane coupling agents, silane coupling agents having an amino group are preferred.

The silane coupling agent is preferably added in an amount of 0.25 to 3.00% by mass, more preferably 0.5 to 2.75% by mass, and still more preferably 0.75 to 2.50% by mass in the protective layer. It is. When the addition amount exceeds 3.00% by mass, curing of the film proceeds and cohesion is improved, but a partially unreacted portion is also generated, and the adhesion between layers may be reduced. On the other hand, when the addition amount is less than 0.25% by mass, sufficient cohesion may not be obtained.

When forming a protective layer with the resin composition for protective layers, the coating liquid (coating liquid) which consists of said polyurethane resin, ion-exchange water, and a water-soluble organic solvent may be prepared, and it may apply and dry on a substrate film. As the water-soluble organic solvent, single or mixed solvents selected from alcohols such as ethanol and isopropyl alcohol (IPA), ketones such as acetone and methyl ethyl ketone can be used, and from the viewpoint of coating film processing and odor Is preferably IPA.

The coating method of the resin composition for protective layers is not particularly limited as long as it is a method of coating on the film surface to form a layer. For example, usual coating methods such as gravure coating, reverse roll coating, wire bar coating, die coating and the like can be employed.

When forming the protective layer, it is preferable to heat and dry after applying the resin composition for the protective layer, and the drying temperature at that time is preferably 110 to 190 ° C., more preferably 130 to 190 ° C., further preferably Is 150-190 ° C. If the drying temperature is less than 110 ° C., insufficient drying may occur in the protective layer, or the film formation of the protective layer may not proceed, and the cohesion and water-resistant adhesion may be reduced, resulting in a decrease in hand cutability. On the other hand, if the drying temperature exceeds 190 ° C., heat may be applied to the film to make the film brittle or shrink and the processability may be deteriorated. In particular, by drying at 150 ° C. or higher, preferably 160 ° C. or higher, the film formation of the protective layer effectively proceeds, and the adhesion area between the resin of the protective layer and the inorganic thin film layer becomes larger, thereby improving water-resistant adhesion. can do. In addition to the drying, additional heat treatment (for example, 150 to 190 ° C.) may be more effective in promoting the film formation of the protective layer.

[Lamination with heat sealable resin layer]
When the laminated film of the present invention is used as a packaging material, it is necessary to include a heat sealable resin layer called a sealant. The heat-sealable resin layer is usually provided on the inorganic thin film side, ie, the protective layer side, but may be provided on the outer side of the substrate film (the side opposite to the surface on which the cover layer is formed). The formation of the heat sealable resin layer is usually carried out by an extrusion laminating method or a dry laminating method. The thermoplastic polymer forming the heat-sealable resin layer may be any one that can exhibit sufficient sealant adhesiveness, polyethylene resins such as HDPE, LDPE, LLDPE, polypropylene resin, ethylene-vinyl acetate copolymer Ethylene-α-olefin random copolymer, ionomer resin, etc. can be used. The thickness of the heat sealable resin layer is preferably 20 μm or more, more preferably 25 μm or more, still more preferably 30 μm or more, preferably 80 μm or less, more preferably 75 μm or less, still more preferably 70 μm or less. Productivity falls that thickness is 20 micrometers or less. On the other hand, if it is 80 μm or more, the cost increases and the transparency also deteriorates.

[Other layer]
In the laminated film of the present invention, at least one or more layers of a printing layer or another plastic substrate and / or a paper substrate are laminated between or outside the inorganic thin film layer or substrate film and the heat sealable resin layer. It may be

As a printing ink which forms a printing layer, resin-containing printing ink of water-based and solvent system can be used preferably. Here, as a resin used for printing ink, acrylic resin, urethane resin, polyester resin, vinyl chloride resin, vinyl acetate copolymer resin, and a mixture thereof are exemplified. For printing inks, known are antistatic agents, light blocking agents, ultraviolet light absorbers, plasticizers, lubricants, fillers, colorants, stabilizers, lubricants, antifoaming agents, crosslinking agents, blocking agents, antioxidants, etc. Additives may be included. It does not specifically limit as a printing method for providing a printing layer, Well-known printing methods, such as an offset printing method, a gravure printing method, the screen-printing method, can be used. For drying of the solvent after printing, known drying methods such as hot air drying, hot roll drying, infrared drying and the like can be used.

On the other hand, from the viewpoint of obtaining sufficient rigidity and strength of the laminate, paper, polyester resin, biodegradable resin and the like are preferably used as other plastic substrates and paper substrates. Moreover, in order to set it as the film excellent in mechanical strength, stretched films, such as a biaxially stretched polyester film, are preferable.

The laminated film of the present invention preferably has an oxygen permeability of 7 ml / m ² · d · MPa or less after storage under a high temperature and high humidity environment, and exhibits good gas barrier properties by being in this range. Furthermore, by controlling the above-mentioned protective layer component and adhesion amount, it is preferably 6 ml / m ² · d · MPa or less, more preferably 5 ml / m ² · d · MPa or less. If the oxygen permeability is 7 ml / m ² · d · MPa or more, it will be difficult to cope with applications requiring high gas barrier properties.

The laminated film of the present invention preferably has a wet lamination strength of 1.5 N / 15 mm or more after storage under high temperature and high humidity environment, more preferably 2.0 N / 15 mm or more, still more preferably 2.5 N / 15 mm or more It is. If the laminate strength is 1.5 N / 15 mm or less, peeling may occur due to bending load or the contents of the liquid, and the barrier properties may be degraded or the contents may leak out. Furthermore, there is also a possibility that the hand cuttability may deteriorate.

EXAMPLES The present invention will next be described in detail by way of examples and comparative examples, but the present invention is of course not limited to the following examples. In addition, unless there is particular notice, "%" means "mass%" and "part" means a "mass part."
The evaluation method used in the present invention is as follows.

(1) Preparation of laminated laminate for evaluation On the protective layer surface of the laminated film obtained in Examples and Comparative Examples, the thickness after drying treatment of a polyurethane adhesive (TM569 manufactured by Toyo Moreton Co., Ltd.) at 80 ° C. becomes 3 μm After coating, a low density linear polyethylene film (L4102 manufactured by Toyobo; thickness 40 μm; LL) is dry laminated on a metal roll heated to 60 ° C. and aged at 40 ° C. for 4 days, A laminated gas barrier laminate (hereinafter sometimes referred to as "laminated laminate A") for evaluation was obtained.

(2) Evaluation Method of Oxygen Permeability Regarding the laminate A prepared in the above (1), according to JIS-K7126 B method, an oxygen permeability measurement apparatus ("OX-TRAN (registered trademark) 1/1 manufactured by MOCON Co., Ltd.) The normal oxygen permeability was measured under an atmosphere of temperature 23.degree. C. and humidity 65% RH using the above 50 "). The oxygen permeability was measured in the direction in which oxygen permeates from the base film side of the laminate to the heat sealable resin layer side.

(3) Evaluation method of laminate strength
The laminate laminate A prepared above is cut into a width of 15 mm and a length of 200 mm in the width direction (TD direction) and the length direction (MD direction) of the base film to form a test piece, temperature 23 ° C., relative humidity The laminate strength was measured under a condition of 65% using a Tensilon universal material tester (“Tensilon UMT-II-500” manufactured by Toyo Boldwin Co., Ltd.). In the measurement of laminate strength, a tensile speed was 200 mm / min, water was applied between the laminated film layers obtained in the examples and comparative examples and the heat sealable resin layer, and peeling was performed at a peeling angle of 90 degrees. The strength of the time was measured. On the other hand, wet heat treatment at 80 ° C. × 80% RH × 6 h is performed on the laminate laminate A prepared in (1), and immediately after the obtained retort-treated laminate laminate in the same manner as described above The laminate was cut out and the laminate strength (after wet heat treatment) was measured in the same manner as described above.

(4) Method of Measuring Surface Hardness of Film The surface hardness of the film was measured using a dynamic ultra-microhardness tester (“DUH-211” manufactured by Shimadzu Corporation). Specifically, a hardness measurement test is carried out by a load unloading test using an interval between angles of 115 ° with a diamond triangle indenter (Berkobitch type) on the protective layer side of a single laminated film fixed and held on a glass plate with an adhesive. The obtained Martens hardness was taken as the value of surface hardness. The test conditions were a test force of 0.1 mN, a loading speed of 0.02 mN / s, and a holding time of 2 seconds.

Each material used for formation of a coating layer and a protective layer in each example and comparative example was prepared as follows.

<Preparation of each material used for coating layer or protective layer formation>
[Polyester resin (A)]
As a polyester resin, "AGN 201" (solid content 25%) manufactured by Takemoto Yushi Co., Ltd., which is a water-dispersible acrylic graft polyester resin containing self-crosslinkable maleic anhydride as a graft chain, was prepared.

[Urethane resin (B)]
As a urethane resin, a dispersion of a commercially available metaxylylene group-containing urethane resin ("Takelac (registered trademark) WPB 341" manufactured by Mitsui Chemicals, Inc .; solid content: 30%) was prepared. The acid value of this urethane resin was 25 mg KOH / g, and the glass transition temperature (Tg) measured by DSC was 130 ° C. Further, the proportion of aromatic or araliphatic diisocyanate to the entire polyisocyanate component measured by 1 H-NMR was 85 mol%.

[Silane coupling agent (C)]
A commercially available Shin-Etsu Chemical "(registered trademark) KBM 903; solid content 100%) was prepared as a silane coupling agent.

[Urethane resin (D)]
As a urethane resin, commercially available dispersion of polyester urethane resin ("Takelac (registered trademark) WS6021" manufactured by Mitsui Chemicals, Inc .; solid content 30%) was prepared. The acid value of this urethane resin was 25 mg KOH / g, and the glass transition temperature (Tg) measured by DSC was 40.degree.

[Urethane resin (E)]
A commercially available polyester urethane resin dispersion ("Hydran (registered trademark) AP-201" manufactured by DIC; solid content 23%) was prepared as the urethane resin. The acid value of this urethane resin was 25 mg KOH / g, and the glass transition temperature (Tg) measured by DSC was 10 ° C.

[Gas barrier ethylene-vinyl alcohol resin composition coating liquid (F)]
Preparation of Ethylene-Vinyl Alcohol Copolymer Solution
An ethylene-vinyl alcohol copolymer (trade name: SOANOL (registered trademark) V2603, manufactured by Japan Synthetic Chemical Co., Ltd., ethylene-vinyl acetate copolymer, in a mixed solvent of 20.996 parts of purified water and 51 parts of n-propyl alcohol (NPA) A polymer obtained by saponifying a polymer, an ethylene ratio of 26 mol%, a saponification degree of about 100% of a vinyl acetate component, and 15 parts of EVOH hereinafter added, and a hydrogen peroxide solution having a concentration of 30% 13 parts and 0.004 parts of FeSO 4 were added and heated to 80 ° C. with stirring, and reacted for about 2 hours. After cooling, catalase was added to 3000 ppm to remove residual hydrogen peroxide, thereby obtaining an almost clear ethylene-vinyl alcohol copolymer solution (EVOH solution) with a solid content of 15%.
<Preparation of Inorganic Layered Compound Dispersion>
Add 4 parts of montmorillonite (trade name: Kunipia (registered trademark) F, manufactured by Kunimin Kogyo Co., Ltd.), which is an inorganic layered compound, in 96 parts of purified water while stirring, and fully set at a pressure of 50 MPa with a high pressure dispersing device. Dispersed. Thereafter, the mixture was kept at 40 ° C. for 1 day to obtain an inorganic layered compound dispersion having a solid content of 4%.
<Additives>
Zirconium Hydrochloride (Daiichi Rare Element Chemical Co., Ltd., trade name; Zircozole (registered trademark) ZC-20, solid content 20%)
<Preparation of Coating Liquid (F)>
31.75 parts of the EVOH solution was added to 62.30 parts of mixed solvent A (a solvent consisting of 40% purified water and 60% n-propyl alcohol), and the mixture was sufficiently stirred and mixed. Further, 5.95 parts of an inorganic layered compound dispersion liquid was added to this solution while performing high-speed stirring. Three parts of cation exchange resin are added to 100 parts of the mixed solution, and stirring is performed for 1 hour at a stirring speed at which crushing of the ion exchange resin does not occur to remove cations, and then cation exchange is performed. Only the resin was filtered out with a strainer. The mixed solution obtained from the above operation is further dispersed in a high pressure dispersing apparatus under the setting of a pressure of 50 MPa, and then 0.75 part of zirconium chloride with respect to 97 parts of the dispersed mixture, and mixed solvent A2. 25 parts were added and mixed and stirred, and the mixture was filtered through a filter of 255 mesh to obtain a coating liquid 3 for a protective layer having a solid content of 5%.

Example 1
(1) Preparation of Coating Composition 1 Used for Coating Layer The following coating agents were mixed to prepare Coating Composition 1. Here, the mass ratio in terms of solid content of the polyester resin (A) is as shown in Table 1.

Water 33%
Isopropanol 7%
Polyester resin (A) 60%

(2) Preparation of Coating Composition 2 Used for Protective Layer The following coating agents were mixed to prepare Coating Composition 2. Here, the mass ratio in terms of solid content of the urethane resin (B) is as shown in Table 1.

Water 41.61%
Isopropanol 40.00%
Urethane resin (B) 18.15%
Silane coupling agent (C) 0.24%

(3) Production of polyamide base film and coating of coating liquid 1 (lamination of coating layer)
Polycaproamide was heated and melted at 260 ° C with a screw extruder, extruded from a T-die into a sheet, and then this unstretched sheet was longitudinally stretched 3.3 times at 80 ° C between a heating roll and a cooling roll . And the said coating liquid 1 was apply | coated by the fountain-bar coat method on the single side | surface of the obtained uniaxially stretched film. Next, it was introduced into a tenter, stretched in the transverse direction 4.0 times at 120 ° C., and heat-set at 215 ° C. to form a coating layer of 0.075 g / m ² on a 15 μm thick biaxially stretched polyamide film A laminated film was obtained.

(4) Formation of Inorganic Thin Film Layer A complex oxide layer of silicon dioxide and aluminum oxide was formed as an inorganic thin film layer on the surface of the film obtained in (3) above by an electron beam evaporation method. As deposition sources, particulate SiO ₂ (purity 99.9%) and Al ₂ O ₃ (purity 99.9%) of about 3 mm to 5 mm were used. Here, the composition of the composite oxide layer was SiO ₂ / Al ₂ O ₃ (mass ratio) = 70/30. The film thickness of the inorganic thin film layer (SiO ₂ / Al ₂ O ₃ composite oxide layer) in the film (inorganic thin film layer / coating layer-containing film) thus obtained was 13 nm. Thus, a vapor deposition film provided with the coating layer and the inorganic thin film layer was obtained.

(5) Coating of coating liquid 2 on deposited film (lamination of protective layer)
The coating liquid 2 prepared in the above (2) was applied onto the inorganic thin film layer of the vapor-deposited film obtained in (4) by the gravure roll coating method, and dried at 170 ° C. to obtain a protective layer. The applied amount after drying was 0.33 g / m ² (Dry).
As described above, a laminated film provided with a coating layer / inorganic thin film layer / protective layer on a base film was produced. The surface hardness, oxygen permeability, and laminate strength were evaluated for the obtained laminated film as described above. The results are shown in Table 1.

(Examples 2 to 5, Comparative Examples 1 to 3)
In preparing a coating liquid for forming a protective layer, a laminated film is produced in the same manner as in Example 1 except that the compounding amount, adhesion amount and type of resin are changed as shown in Table 1, The surface hardness, oxygen permeability, and laminate strength were evaluated. The results are shown in Table 1.

It turned out that the gas barrier laminated film provided with the coating layer, the inorganic thin film layer, and the protective layer of this invention is excellent in gas barrier property and water-resistant adhesiveness. As a result, peeling does not occur even with the bending load or the contents of the water system, and there is no problem that the barrier property is deteriorated or the contents leak out. In addition, since the laminated film of the present invention is designed as a protective layer of surface hardness which can follow the expansion and contraction of the nylon base film in a high temperature and high humidity environment, damage to the inorganic layer by shear stress, It is possible to prevent a decrease in adhesion strength due to delamination. Moreover, since the laminated film of the present invention has few processing steps and can be easily manufactured, it is excellent in both economical efficiency and production stability, and a gas barrier film of homogeneous characteristics can be provided.

Claims

A coating layer is provided on at least one side of a polyamide base film, and the coating layer is made of a resin composition for a coating layer containing a polyester resin as a component, and an inorganic thin film layer is provided on the coating layer. A laminated film having a protective layer containing a urethane resin having a metaxylylene group on a layer, wherein the surface hardness of the protective layer of the laminated film is 220 to 310 N / mm 2 .
The polyester film contained in the said coating layer is acrylic graft polyester resin, The laminated film of Claim 1 characterized by the above-mentioned.
The laminated film according to claim 1, wherein the inorganic thin film layer is a layer formed of a composite oxide of silicon oxide and aluminum oxide.