JP2022050456A - Laminated laminate - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a laminated film which has good barrier property and water-resistant adhesion and sufficiently hand tearability, and facilitates manufacture and is excellent in economical efficiency, when formed into a gas barrier laminated film having an inorganic thin film layer.

SOLUTION: A laminated laminate is obtained by laminating a linear low density polyethylene film on a laminated film obtained by laminating a coating layer, an inorganic thin film layer and a protective layer in this order on at least one surface of a polyamide base material film through or without through another layer, through a polyurethane-based adhesive, in which the coating layer contains a maleic acid-grafted polyester resin, the protective layer contains an urethane resin containing a m-xylylene group, and a test force (P1) when the laminated laminate is immersed in the water for 10 seconds, is taken out from the water and then is torn by 5 mm by a tensile tester and a test force (P2) when the laminated laminate is torn by 30 mm satisfy Expression [1].

SELECTED DRAWING: None

COPYRIGHT: (C)2022,JPO&INPIT

Description

The present invention relates to a laminated film used in the packaging field of foods, pharmaceuticals, industrial products and the like. More specifically, the present invention relates to a laminated film provided with a base film, a coating layer, an inorganic thin film layer, and a protective layer, which can exhibit good gas barrier property, water adhesion resistance (laminate strength), and hand-cutting property.

Packaging materials used in foods, pharmaceuticals, etc. must have the property of blocking gases such as oxygen and water vapor, that is, gas barrier properties, in order to suppress the oxidation of proteins and fats and oils, maintain the taste and freshness, and maintain the efficacy of pharmaceuticals. It has been demanded. Further, gas barrier materials used for electronic devices such as solar cells and organic ELs and electronic parts require higher gas barrier properties than packaging materials such as foods.

Conventionally, in food applications that require blocking of various gases such as water vapor and oxygen, a metal thin film made of aluminum or the like and an inorganic oxide such as silicon oxide or aluminum oxide are formed on the surface of a base film made of plastic. A gas barrier laminate having a thin film 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, and a mixture thereof are widely used because they are transparent and the contents can be confirmed.

However, since the above-mentioned gas barrier laminate tends to be locally heated to a high temperature in the forming process, the base material is damaged, and decomposition or degassing occurs in the low molecular weight portion or the additive portion such as a plasticizer. As a result, defects, pinholes, etc. may occur in the inorganic thin film layer, and the gas barrier property may be deteriorated. Further, there is a problem that the inorganic thin film layer is cracked and cracked during the post-processing of the packaging material such as printing, laminating, and bag making, and the gas barrier property is deteriorated.

As a method for improving the defects of the gas barrier laminated body on which the inorganic thin film layer is formed, an attempt has been made to provide a protective layer having a gas barrier property on the inorganic thin film layer. For example, there is a method of laminating a gas barrier resin composed of an ethylene-vinyl alcohol-based copolymer, an inorganic layered compound, and an additive (for example, Patent Document 1). In this method, the drawbacks of the inorganic thin film layer and the gas barrier property are greatly improved.

However, in the above method, the interlayer adhesiveness is lowered due to the lack of water resistance of the protective layer. The film having reduced interlayer adhesiveness has a problem that peeling occurs due to a bending load or the contents of the liquid, the barrier property is deteriorated, and the contents leak out. Further, if the protective layer itself is not water resistant, there is a practical problem that it is difficult for a consumer to cut a film filled with a liquid content by hand.

To solve these problems, a water-soluble polymer, an inorganic layered compound, and a metal alkoxide or a hydrolyzate thereof are coated on the inorganic thin film layer, and the inorganic layer containing the inorganic layered compound and water-soluble on the inorganic thin film layer by the sol-gel method. A method for 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 water resistance, but due to the low stability of the liquid applied to the coating, it is distributed at the start and end of the coating (for example, industrially distributed). In the case of a roll film to be used, the characteristics differ depending on the outer peripheral part and the inner peripheral part of the roll), the characteristics differ due to a slight temperature difference in drying or heat treatment in the film width direction, and the quality differs depending on the manufacturing environment. Had a problem that it occurred greatly. Furthermore, since the film coated by the sol-gel method has poor flexibility, it has been pointed out that when the film is bent or impacted, pinholes and cracks are likely to occur and the gas barrier property may be deteriorated. ..

Against this background, it is desired to improve the ability to form a resin layer on an inorganic thin film layer by a coating method that does not involve a sol-gel reaction, that is, a coating method that mainly uses a resin and involves a cross-linking reaction at the time of coating. rice field. Examples of the gas barrier laminate with such improvements include a gas barrier laminate in which a barrier resin containing a silane coupling agent is coated on an inorganic thin film (for example, Patent Document 3), and a methaxylylene group-containing polyurethane on the inorganic thin film. Examples thereof include a coated laminate (for example, Patent Document 4).

Patent No. 5434341 Japanese Unexamined Patent Publication No. 2000-43182 Patent No. 3441594 Patent No. 4524463

However, any of the above-mentioned methods is a gas barrier that is excellent in production stability and economy during manufacturing, has good barrier properties and water-resistant adhesiveness, and has sufficient hand-cutting property in a wet state in which water is present. At present, no film has been obtained.

In the above-mentioned Patent Document 3, improvement of the barrier property before and after hand-kneading has been studied, and good results have been obtained, but improvement of water-resistant adhesiveness and hand-cutting property has not been studied. Further, in Patent Document 4, the humidity dependence of oxygen permeability has been investigated and good values have been shown for each, but the improvement of water adhesion resistance and hand-cutting property has not been studied either.

As a result of diligent studies to solve the above problems, the present inventor has provided a specific coating layer, an inorganic thin film layer and a protective layer on at least one surface of the base film, thereby providing good barrier properties and water resistance. The present invention has been completed by finding a laminated film having sufficient hand-cutting property in a wet state in which water is present.

The gas barrier laminated film of the present invention, which solves the above problems, has the following aspects.

(1) A polyurethane-based adhesive is used on a laminated film in which a coating layer, an inorganic thin film layer, and a protective layer are laminated in this order on at least one surface of a polyamide base film with or without another layer. A laminated laminate obtained by laminating a linear low-density polyethylene film, the coating layer containing a maleic anhydride-grafted polyester resin, the protective layer containing a urethane resin containing a metaxylylene group, and the laminate. After immersing the laminate in water for 10 seconds, the test force (P1) when the laminate is taken out of the water and torn by a tensile tester by a tensile tester (P1) and the test force (P2) when the laminate is torn by 30 mm satisfy the following formula [1]. Laminated laminate featuring.

(2) The laminated laminate according to (1), wherein the protective layer contains at least one of a silicon-based cross-linking agent and a carbodiimide-based cross-linking agent.

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

According to the present invention, when a gas barrier laminated film provided with a coating layer, an inorganic thin film layer and a protective layer is formed, it has excellent water-resistant adhesiveness, so that peeling does not occur even with a bending load or water-based contents. There is no problem that the barrier property deteriorates or the contents leak out. In addition, since the inorganic thin film layer is sandwiched between a coating layer and a protective layer having strong cohesive force, and the adhesion between the layers is good and the water resistance is also good, the consumer can manually press the film filled with the contents. When cutting, stress propagation is easy, and sufficient hand-cutting property can be exhibited even when water-based contents are present. Moreover, since the laminated film of the present invention can be easily manufactured with few processing steps, it is excellent in both economic efficiency and production stability, and it is possible to provide a gas barrier film having uniform characteristics.

The laminated film of the present invention comprises a coating layer, an inorganic thin film layer, and a protective layer laminated on one side or both sides of a polyamide base film in this order with or without other layers. The test force (P1) and the test force (P1) when the laminated laminate obtained by laminating the film and the linear low-density polyethylene film via a polyurethane adhesive was immersed in water for 10 seconds, then taken out of the water and torn by a tensile tester by 5 mm. It is a laminated film characterized in that the test force (P2) when torn by 30 mm satisfies the following formula [1].

The above equation [1] represents how much the tearing force changes immediately after the start of tearing and when tearing a certain distance. When the formula [1] is within the above range, the force required for tearing is kept constant, so that when the consumer actually tears by hand, stress propagation between the layers is easy and stable. It can be torn with a strong force, resulting in a film with good hand-cutting property. The preferred range of the formula [1] is more preferably 0.8 or less, still more preferably 0.7 or less. When it is 1 or more, stress propagation between each layer is difficult, stress is applied more as it tears, and there is a possibility that hand cutting property becomes worse.

The present inventors have focused on the fact that the tearability of the laminated film (hereinafter, may be referred to as hand-cutting property) may be significantly different between the normal condition and the wet state in which water is present. In particular, although the tearability is good under normal conditions, the tearability may deteriorate under a wet state in which water is present, which poses a practical problem. Conventionally, it has been considered that the tearability of the thickest base film in the structure of the laminated film determines the tearability of the laminated film. As a result of diligent studies by the inventors, it has been newly found that the cause is that the adhesive force between the layers of the laminated film is weakened in a wet state in which water is present, and the tearing force is difficult to propagate between the layers. Furthermore, the present inventors have found that increasing the cohesive force of each layer of the laminated film other than the base film also has the effect of improving the tearability, and have completed the present invention.

Hereinafter, the base film and each layer laminated on the base film will be described in order.

[Base film]
As the base film used in the present invention (hereinafter sometimes referred to as "base film"), a polyamide base film typified by nylon 4.6, nylon 6, nylon 6/6, nylon 12, etc. is used. .. The polyamide base film is superior to other resin base films in terms of bag breakage resistance and pinhole resistance. Examples of the polyamide resin used in the present invention include nylon 6 containing ε-caprolactam as a main raw material. Examples of other polyamide resins include polyamide resins obtained by polycondensation of lactam, ω-amino acid, dibasic acid and diamine having a 3-membered ring or more. Specifically, as lactams, in addition to ε-caprolactam shown above, enantractam, capryllactam, lauryllactam, and as ω-amino acids, 6-aminocaproic acid, 7-aminoheptanoic acid, 9- Aminononanoic acid and 1,1-aminoundecanoic acid can be mentioned. Examples of dibasic acids include adipic acid, glutaric acid, pimelic acid, suberic acid, azelaic acid, sebacic acid, undecandionic acid, dodecazionic acid, hexadecazionic acid, eikosandionic acid, eikosaziendionic acid, 2 , 2,4-trimethyladipic acid, terephthalic acid, isophthalic acid, 2,6-naphthalenedicarboxylic acid, xylylene dicarboxylic acid. Further, as diamines, ethylenediamine, trimethylenediamine, tetramethylenediamine, hexamethylenediamine, pentamethylenediamine, undecamethylenediamine, 2,2,4 (or 2,4,4) -trimethylhexamethylenediamine, cyclohexane Examples thereof include diamine, bis- (4,4'-aminocyclohexyl) methane, and metaxylylenediamine. Then, a polymer obtained by polycondensing these or a copolymer thereof, for example, nylon 6, 7, 11, 12, 6.6, 6.9, 6.11, 6.12, 6T, 6I, MXD6. (Metaxylene panamide 6), 6 / 6.6, 6/12, 6/6 T, 6 / 6I, 6 / MXD6 and the like can be used. In addition, in the case of producing the polyamide resin laminated film roll before vapor deposition of the present invention, the above-mentioned polyamide resin can be used alone or in combination of two or more.

As the base film, a film having an arbitrary film thickness can be used according to a desired purpose and application such as mechanical strength and transparency, and the film thickness is not particularly limited, but is usually 5 to 100 μm. Is recommended, and when used as a packaging material, it is preferably 8 to 60 μm. The transparency of the base film is not particularly limited, but when it is used as a packaging material that requires transparency, it is desirable that the base film has a light transmittance of 50% or more.

From the viewpoint of imparting mechanical strength, the polyamide base film is preferably a stretched film stretched in at least one direction in the vertical direction or the horizontal direction, and is biaxially stretched in two directions in the vertical direction and the horizontal direction. A stretched film is more preferable. As the 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 uniform state of the stretching method in the sequential biaxial stretching, the unstretched film is stretched in the vertical direction at a temperature of 70 ° C. to 90 ° C. at a stretching ratio of 3.0 to 4.5 times in the vertical direction by a roll type stretching machine. A method of stretching, then stretching at a stretching ratio of 3.5 to 5.5 times at a temperature of 110 ° C. to 140 ° C. using a tenter type stretching machine, and then heat-treating at a temperature of 180 ° C. to 230 ° C. after stretching is given. be able to. Further, when the in-line coating method is adopted as the step of forming the coating layer described later, in the above-mentioned sequential biaxial stretching step, the coating layer is coated on the film after stretching in the longitudinal direction, and then continuously. The film can be guided to a tenter type stretching machine for lateral stretching and heat treatment.

The base film may be a single-layer film made of a polyamide resin, or may be a laminated film in which a polyamide resin layer and another plastic film (which may be two or more) are laminated. .. The type of the laminated body in the case of forming a laminated film is not particularly limited as long as there is a polyamide resin layer, and the number of laminated films, the laminating method, and the like are not particularly limited, 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 base material, a desired surface treatment layer can be provided in advance, if necessary.
In the present invention, the surface treatment layer includes, for example, corona discharge treatment, ozone treatment, low temperature plasma treatment using oxygen gas or nitrogen gas, glow discharge treatment, oxidation treatment using chemicals, and the like. Etc. can be arbitrarily applied to form, for example, a corona-treated layer, an ozone-treated layer, a plasma-treated layer, an oxidation-treated layer, and the like. The above surface pretreatment is carried out as a method for improving the tight adhesion between various resin films and the vapor-filmed film of a metal oxide, but as a method for improving the tight adhesion, there are others. For example, a primer coating agent layer, an undercoat agent layer, an anchor coating agent layer, an adhesive layer, a vapor-deposited anchor coating agent layer, etc. are arbitrarily formed and coated on the surface of various resin films in advance. It can also be a layer.

[Coating layer]
In order to improve the adhesion strength between the base material layer and the inorganic thin film layer by forming the coating layer, it is preferable to use a polyester resin from the viewpoint of cost and hygiene. Such a polyester resin can be obtained by polycondensing a dicarboxylic acid or a tricarboxylic acid with glycols. Examples of the component 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, in this polyester-based resin, by forming an acrylic monomer graft-copolymerized, the film is cured and the cohesive force 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 coating layer can be uniformly controlled, and as a result, the inorganic thin film layer can be densely deposited. In addition, the cohesive force inside the coating layer is improved, and the adhesion between the layers of the base film-coating layer-inorganic thin film layer is also increased, so that the water resistance and hand-cutting property of the coating layer can be improved. The adhesion amount of the coating layer is preferably 0.015 g / m ² or more, more preferably 0.020 g / m ² or more, still more preferably 0.025 g / m ² or more, and preferably 0.190 g / m ² or less. , More preferably 0.180 g / m ² or less, still more preferably 0.170 g / m ² or less. If the amount of adhesion of the coating layer exceeds 0.200 g / m ² , the cohesive force inside the coating layer becomes insufficient, and good hand-cutting property may not be exhibited. In addition, since the uniformity of the coating layer is also lowered, defects may occur in the inorganic thin film layer, and the gas barrier property may be lowered. Moreover, the manufacturing cost becomes high, which 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 may not be sufficiently coated, and sufficient gas barrier properties and interlayer adhesion may not be obtained.

The resin composition for the coating layer contains various known inorganic and organic additives such as an antistatic agent, a slip agent, and an anti-blocking agent, if necessary, as long as the present invention is not impaired. May be good.

The method for forming the coating layer is not particularly limited, and a conventionally known method such as a coating method can be adopted. Among the coating methods, the offline coating method and the inline coating method can be mentioned as preferable methods. For example, in the case of the in-line coating method performed in the process of manufacturing a base film, the conditions of drying and heat treatment at the time of coating depend on the coating thickness and the conditions of the apparatus, but immediately after coating, they are sent to the stretching process in the perpendicular direction and stretched. It is preferable to dry in the preheating zone or the stretching zone of the step, and in such a case, the temperature is usually preferably about 50 to 250 ° C.

[Inorganic thin film layer]
In the laminated film of the present invention, an inorganic thin film layer is laminated above the coating 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), and a mixture of silicon oxide and aluminum oxide (composite oxide). ) And the like are preferably mentioned. In particular, a composite oxide of silicon oxide and aluminum oxide is preferable from the viewpoint of achieving both flexibility and denseness 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% for Al in terms of the mass ratio of the metal content. 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 destroyed during secondary processing such as printing or laminating. There is a risk that the barrier property will be reduced. The silicon oxide referred to here is various silicon oxides such as SiO and SiO ₂ or a mixture thereof, and the aluminum oxide is various aluminum oxides such as AlO and Al ₂ O ₃ or a mixture thereof.

The film 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, it may be difficult to obtain a satisfactory gas barrier property. On the other hand, even if the thickness exceeds 100 nm, the corresponding improvement effect of the gas barrier property can be obtained. However, it is disadvantageous in terms of bending resistance and manufacturing cost.

The method for forming the inorganic thin film layer is not particularly limited, and is known, for example, a physical vapor deposition method (PVD method) such as a vacuum vapor deposition method, a sputtering method, or an ion plating method, or a chemical vapor deposition method (CVD method). The method may be adopted as appropriate. Hereinafter, a typical method for forming an inorganic thin film layer will be described using a silicon oxide / aluminum oxide thin film as an example. For example, when the vacuum vapor deposition method is adopted, a mixture of SiO ₂ and Al ₂ O ₃ or a mixture of SiO ₂ and Al is preferably used as the vapor deposition raw material. Particles are usually used as these vapor deposition raw materials, but at that time, it is desirable that the size of each particle is such that the pressure at the time of vapor deposition does not change, and the preferable particle diameter is 1 mm to 5 mm. For heating, methods such as resistance heating, high frequency induction heating, electron beam heating, and laser heating can be adopted. Further, it is also possible to introduce oxygen, nitrogen, hydrogen, argon, carbon dioxide gas, water vapor or the like as the reaction gas, or to adopt reactive vapor deposition using means such as ozone addition and ion assist. Further, the film forming conditions can be arbitrarily changed, such as applying a bias to the film to be vapor-deposited (laminated film to be subjected to vapor deposition) or heating or cooling the film to be vapor-deposited. Such a vapor deposition material, a reaction gas, a bias of the vapor-film-deposited body, heating / cooling, and the like can be similarly changed when the sputtering method or the CVD method is adopted.

[Protective layer]
In the present invention, the protective layer is provided on the inorganic thin film layer. The inorganic thin film layer laminated on the plastic film is not a completely dense film, but is dotted with minute defects. By applying a specific protective layer resin composition to be described later on the inorganic thin film layer to form the protective layer, the resin in the protective layer resin composition permeates the defective portion of the inorganic thin film layer, and as a result. The effect of stabilizing the gas barrier property can be obtained. In addition, by using a material having a gas barrier property for the protective layer itself, the gas barrier performance of the laminated film is greatly improved. Further, by improving the cohesive force and the adhesiveness of the protective layer, it is possible to obtain a film having excellent hand-cutting property.

In the present invention, the amount of the protective layer adhered is preferably 0.10 to 0.60 g / m ² . As a result, the protective layer can be uniformly controlled during coating, resulting in a film having less coating unevenness and defects. In addition, the cohesive force of the protective layer itself is improved, the adhesion between the inorganic thin film layer and the protective layer is strengthened, and the hand-cutting property can be enhanced. The amount of the protective layer adhered is preferably 0.13 g / m ² or more, more preferably 0.16 g / m ² or more, still more preferably 0.19 g / m ² or more, and preferably 0.57 g / m ² or less. , More preferably 0.54 g / m ² or less, still more preferably 0.51 g / m ² or less. When the amount of adhesion of the protective layer exceeds 0.600 g / m ² , the gas barrier property is improved, but the cohesive force inside the protective layer is insufficient, and the uniformity of the protective layer is also lowered, so that the appearance of the coat becomes uneven. Defects may occur, or gas barrier properties, adhesiveness, and hand-cutting properties may not be fully exhibited. On the other hand, if the film thickness of the protective layer is less than 0.10 g / m2, sufficient gas barrier properties and interlayer adhesion may not be obtained.

In the present invention, urethane resin is used for the protective layer. The urethane resin has a polar urethane bonding portion, so that the urethane resin has good adhesion to the inorganic thin film layer, and the resin easily penetrates into the defective portion. Further, since there is a crystal portion having a high cohesive force due to hydrogen bonds between urethane bonds, stable gas barrier performance can be obtained. Further, since the amorphous portion having high flexibility also exists at the same time, the surface hardness can be kept within the predetermined range by controlling the ratio of the amorphous portion and the crystalline portion. As the urethane resin, a water-dispersion type resin having high polarity and good wettability to the inorganic thin film layer is preferable. Further, as a curable resin type, a thermosetting resin is desirable from the viewpoint of production stability.

(Urethane resin (A))
The urethane resin (A) can be obtained by reacting the following polyisocyanate component (B) with the following polyol component (C) by a usual method. Further, the chain is extended by reacting a small molecule compound having two or more active hydrogens such as a diol compound (for example, 1,6-hexanediol) and a diamine compound (for example, hexamethylenediamine) as a chain extender. Is also possible.

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

Examples of the aromatic diisocyanate include tolylene diisocyanate (2,4- or 2,6-toluene diisocyanate or a mixture thereof) (TDI), phenylenedi isocyanate (m-, p-phenylenedi isocyanate or a mixture thereof), 4,4. '-Diphenylsiisocyanate, 1,5-naphthalenediocyanate (NDI), diphenylmethane diisocyanate (4,4'-, 2,4'-or 2,2'-diphenylmethane diisocyanate or a mixture thereof) (MDI) , 4,4'-toluene diisocyanate (TODI), 4,4'-diphenyl ether siisocyanate and the like can be exemplified. Examples of the aromatic aliphatic diisocyanate include xylylene diisocyanate (1,3- or 1,4-xylylene diisocyanate or a mixture thereof) (XDI) and tetramethylxylylene diisocyanate (1,3- or 1,4-tetramethyl). Examples thereof include xylylene diisocyanate or a mixture thereof) (TMXDI), ω, ω'-diisocyanate-1,4-diisocyanate and the like.

Examples of the alicyclic diisocyanate include 1,3-cyclopentenediisocyanate, cyclohexanediisocyanate (1,4-cyclohexanediisocyanate, 1,3-cyclohexanediisocyanate), and 3-isocyanatemethyl-3,5,5-trimethylcyclohexylisocyanate (iso). Holodiisocyanate, IPDI), methylenebis (cyclohexylisocyanate) (4,4'-, 2,4'-or 2,2'-methylenebis (cyclohexylisocyanate)) (hydrogenated MDI), methylcyclohexanediisocyanate (methyl-2,4- Cyclohexanediisocyanate, methyl-2,6-cyclohexanediisocyanate), bis (isocyanatemethyl) cyclohexane (1,3- or 1,4-bis (isocyanatemethyl) cyclohexane or a mixture thereof) (hydrogenated XDI) and the like can be mentioned.

Examples of the aliphatic diisocyanate include trimethylene diisocyanate, 1,2-propylene diisocyanate, butylene diisocyanate (tetramethylene diisocyanate, 1,2-butyrenze isocyanate, 2,3-butylenedisocyanate, 1,3-butyrenze isocyanate) and hexamethylene. Examples thereof include diisocyanate, pendamethylene diisocyanate, 2,4,4- or 2,2,4-trimethylhexamethylene diisocyanate, 2,6-diisocyanate methylcaffeite and the like.

(C) Glycol component As the polyol component (particularly the diol component), low molecular weight glycols to oligomers can be used, but from the viewpoint of gas barrier properties, alkylene glycols (for example, ethylene glycol, propylene glycol, trimethylene glycol) are usually used. , 1,3-Butanediol, 1,4-Butanediol, Pentandiol, Hexadiol, Neopentyl glycol, Heptanediol, Octanediol and other linear or branched C2-10 alkylene glycols), (Poly) Oxygen Low molecular weight glycols such as C2-4 alkylene glycol (diethylene glycol, triethylene glycol, tetraethylene glycol, dipropylene glycol, etc.) are used. Preferred glycol components are C2-8 polyol components [eg, C2-6 alkylene glycols (particularly ethylene glycol, 1,2- or 1,3-propylene glycol, 1,4-butanediol, 1,6-hexanediol, etc.). 3-Methyl-1,5-pentanediol), etc.], di or trioxy C2-3 alkylene glycol (diethylene glycol, triethylene glycol, dipropylene glycol, etc.), and a particularly preferable diol component is C2-8 alkylene glycol (particularly C2). -6 alkylene glycol).

These diol components can be used alone or in combination of two or more. Further, if necessary, aromatic diols (eg, bisphenol A, bishydroxyethyl terephthalate, catechol, resorcin, hydroquinone, 1,3- or 1,4-xylylene diol or a mixture thereof, etc.), alicyclic diols (eg, bisphenol A, bishydroxyethyl terephthalate, catechol, resorcin, hydroquinone, etc.), alicyclic diols ( For example, a low molecular weight diol component such as hydrogenated bisphenol A, xylylene diol, cyclohexanediol, cyclohexanedimethanol, etc. may be used in combination. Further, if necessary, a trifunctional or higher functional polyol component, for example, a polyol component such as glycerin, trimethylolethane, or trimethylolpropane can be used in combination. The polyol component preferably contains at least a C2-8 polyol component (particularly, C2-6 alkylene glycol). The ratio of the C2-8 polyol component (particularly, C2-6 alkylene glycol) in 100% by mass of the polyol component can be selected from the range of about 50 to 100% by mass, and is usually preferably 70% by mass or more and 100% by mass or less. It is more preferably 80% by mass or more and 100% by mass or less, and further preferably 90% by mass or more and 100% by mass or less.

In the present invention, it is more preferable to use a urethane resin containing an aromatic or aromatic aliphatic diisocyanate component as a main component from the viewpoint of improving the gas barrier property and the cohesive force. Among them, it is particularly preferable to contain a metaxylylene diisocyanate component. By using the above 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 property and hand-cutting property can be obtained.

The urethane resin preferably has a carboxylic acid group (carboxyl group) from the viewpoint of improving the affinity with the inorganic thin film layer. In order to introduce a carboxylic acid (salt) group into the urethane resin, for example, a polyol compound having a carboxylic acid group such as dimethylolpropionic acid and dimethylolbutanoic acid may be introduced as a copolymerization component as a polyol component. Further, if the carboxylic acid group-containing urethane resin is synthesized and then neutralized with a salt-forming agent, an aqueous dispersion urethane resin can be obtained. Specific examples of the salt forming agent include trialkylamines such as ammonia, trimethylamine, triethylamine, triisopropylamine, tri-n-propylamine and tri-n-butylamine, and N such as N-methylmorpholine and N-ethylmorpholine. -Examples include N-dialkylalkanolamines such as alkylmorpholines, N-dimethylethanolamine and N-diethylethanolamine. 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 mgKOH / g. It is more preferably in the range of 15 to 55 mgKOH / g, and even more preferably in the range of 20 to 50 mgKOH / g. When the acid value of the urethane resin is within the above range, the liquid stability is improved when it is made into an aqueous dispersion, and the protective layer can be uniformly deposited on the highly polar inorganic thin film layer, so that the appearance of the coat is as good as possible. It will be good.

The urethane resin of the present invention preferably has a glass transition temperature (Tg) of 100 ° C. or higher, more preferably 110 ° C. or higher, and even more preferably 120 ° C. or higher. By setting the Tg to 100 ° C. or higher, the cohesive force of the resin is improved, and the hand-cutting property in a wet state in which water is present is excellent.

In the urethane resin of the present invention, various cross-linking agents may be blended for the purpose of improving the cohesive force of the film and the water-resistant adhesiveness as long as the gas barrier property is not impaired. Examples of the cross-linking agent include a silicon-based cross-linking agent, an oxazoline compound, a carbodiimide compound, an epoxy compound and the like. Among them, a silicon-based cross-linking agent or a carbodiimide compound is particularly preferable from the viewpoint of improving the water adhesion resistance to the inorganic thin film layer.

As the silicon-based cross-linking agent, a silane coupling agent is preferable from the viewpoint of cross-linking between an inorganic substance and an organic substance. Examples of the silane coupling agent include hydrolytic alkoxysilane compounds, for example, halogen-containing alkoxysilanes (2-chloroethyltrimethoxysilane, 2-chloroethyltriethoxysilane, 3-chloropropyltrimethoxysilane, 3-chloropropyltri). Chloro C2-4 alkyltri C1-4 alkoxysilane such as ethoxysilane), alkoxysilane with an epoxy group [2-glycidyloxyethyltrimethoxysilane, 2-glycidyloxyethyltriethoxysilane, 3-glycidyloxypropyltrimethoxy) Glycidyloxy C2-4 alkyltri C1-4 alkoxysilane such as silane, 3-glycidyloxypropyltriethoxysilane, glycidyloxydi C2- such as 3-glycidyloxypropylmethyldimethoxysilane and 3-glycidyloxypropylmethyldiethoxysilane 4 Alkyldi C1-4 alkoxysilane, 2- (3,4-epylcyclohexyl) ethyltrimethoxysilane, 2- (3,4-epoxycyclohexyl) ethyltriethoxysilane, 3- (3,4-epylcyclohexyl) propyltri (Epoxycycloalkyl) C2-4alkyltri such as methoxysilane], alkoxysilane having an amino group [2-aminoethyltrimethoxysilane, 3-aminopropyltrimethoxysilane, 3-aminopropyltri Amino C2-4 alkyl tri C1-4 alkoxysilane such as ethoxysilane, aminodi C2-4 alkyl di C1-4 alkocisilane such as 3-aminopropylmethyldimethoxysilane, 3-aminopropylmethyldiethoxysilane, 2- [N-( 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 Alkyl Tri C1-4 Alkylsilane, 3- [N- (2-Aminoethyl) Amino] Propylmethyldimethoxysilane, 3- [N- (2-Aminoethyl) Amino ] (Amino C2-4 alkyl) such as propylmethyldiethoxysilane (aminoC2-4alkyl) Aminodi C2-4alkyldi C1-4alkoxysilane, etc.], alkoxysilanes having a mercapto group (2-mercaptoethyltrimethoxysilane, 3-mercaptopropyltrimethoxysilane) 3, 3 -Mercapto C2-4 alkyltri C1-4 alkoxysilane such as mercaptopropyltriethoxysilane, 3-mercaptopropylmethyldimethoxysilane, mercaptodi C2-4alkyldi C1-4alkoxysilane such as 3-mercaptopropylmethyldiethoxysilane, etc.) , Alkoxysilane having a vinyl group (vinyltriC1-4 alkoxysilane such as vinyltrimethoxysilane, vinyltriethoxysilane, etc.), alkoxysilane having an ethylenically unsaturated bond group [2- (meth) acryloxiethyltrimethoxysilane , 2- (meth) acryloxyethyltriethoxysilane, 3- (meth) acryloxypropyltrimethoxysilane, 3- (meth) acryloxypropyltriethoxysilane, etc. (meth) acryloxy C2-4 alkyltri C1-4 Examples thereof include (meth) acryloxidi C2-4 alkyldi C1-4 alkoxysilanes such as alkoxysilane, 3- (meth) acryloxypropylmethyldimethoxysilane, and 3- (meth) acryloxipropylmethyldiethoxysilane. These silane coupling agents can be used alone or in combination of two or more. Of these silane coupling agents, a silane coupling agent having an amino group is preferable.

The silane coupling agent is preferably added in the protective layer in an amount of 0.25 to 3.00% by mass, more preferably 0.5 to 2.75% by mass, still more preferably 0.75 to 2.50% by mass. Is. If the amount added exceeds 3.00% by mass, the film is cured and the cohesive force is improved, but some unreacted portions are also formed, and the adhesiveness between the layers may be lowered. On the other hand, if the addition amount is less than 0.25% by mass, sufficient cohesive force may not be obtained.

Examples of the carbodiimide compound include a monocarbodiimide compound and a polycarbodiimide compound. Examples of the monocarbodiimide compound include dicyclohexylcarbodiimide, diisopropylcarbodiimide, dimethylcarbodiimide, diisobutylcarbodiimide, dioctylcarbodiimide, t-butylisopropylcarbodiimide, diphenylcarbodiimide, di-t-butylcarbodiimide, di-β-naphthylcarbodiimide and the like. ..

As the polycarbodiimide compound, a compound produced by a conventionally known method can be used. For example, it can be produced by synthesizing an isocyanate-terminated polycarbodiimide by a condensation reaction involving decarbonization of diisocyanate.

Examples of the diisocyanate which is a synthetic raw material of the polycarbodiimide compound include isomers of toluylene diisocyanate, aromatic diisocyanates such as 4,4-diphenylmethane diisocyanate, aromatic aliphatic diisocyanates such as xylylene diisocyanate, isophorone diisocyanate and 4 , 4-Dicyclohexylmethane diisocyanate, alicyclic diisocyanates such as 1,3-bis (isocyanatemethyl) cyclohexane, hexamethylene diisocyanate, and aliphatic diisocyanates such as 2,2,4-trimethylhexamethylene diisocyanate. From the viewpoint of yellowing, aromatic aliphatic diisocyanates, alicyclic diisocyanates, and aliphatic diisocyanates are preferable.

Further, the diisocyanate may be used by controlling the molecule to an appropriate degree of polymerization by using a compound that reacts with a terminal isocyanate such as monoisocyanate. Examples of the monoisocyanate for sealing the end of polycarbodiimide and controlling the degree of polymerization thereof include phenyl isocyanate, toluylene isocyanate, dimethylphenyl isocyanate, cyclohexyl isocyanate, butyl isocyanate, and naphthyl isocyanate. In addition, a compound having an OH group, an NH2 group, a COOH group, and an SO3H group can be used as the terminal encapsulant.

The condensation reaction of diisocyanate with decarbonization proceeds in the presence of a carbodiimidization catalyst. Examples of the catalyst include 1-phenyl-2-phospholene-1-oxide, 3-methyl-2-phospholene-1-oxide, 1-ethyl-2-phospholene-1-oxide, and 3-methyl-1-phenyl-2. Examples thereof include -phospholene-1-oxide and phosphorene oxides such as these 3-phosphoren isomers, and 3-methyl-1-phenyl-2-phospholene-1-oxide is preferable from the viewpoint of reactivity. The amount of the catalyst used can be the amount of the catalyst.

It is desirable that the above-mentioned mono or polycarbodiimide compound be maintained in a uniformly dispersed state when blended into an aqueous paint, and for this purpose, it can be emulsified with an appropriate emulsifier and used as an emulsion, or polycarbodiimide. It is preferred to add a hydrophilic segment within the molecular structure of the compound and blend it into the paint in the form of a self-emulsifying product or in the form of a self-dissolving product.

The degree of polymerization (n) of the polycarbodiimide compound is preferably 2 to 10, more preferably 3 to 7. When the degree of polymerization is small, the cross-linking reaction rate is poor and the adhesion to the functional layer is low, and when the degree of polymerization is high, the compatibility with the resin is poor and the haze may increase.

Examples of the carbodiimide compound used in the present invention include water dispersibility and water solubility. Water solubility is preferable because it has good compatibility with other water-soluble resins and improves the transparency of the coating layer and the cross-linking reaction efficiency.

In order to make the carbodiimide compound water-soluble, an isocyanate-terminated polycarbodiimide is synthesized by a condensation reaction involving decarbonation of isocyanate, and then a hydrophilic moiety having a functional group reactive with the isocyanate group is added. Can be manufactured by

Examples of the hydrophilic moiety include (1) a quaternary ammonium salt of a dialkylaminoalcohol, a quaternary ammonium salt of a dialkylaminoalkylamine, (2) an alkylsulfonate having at least one reactive hydroxyl group, and (3). Examples thereof include poly (ethylene oxide), poly (propylene oxide), and a mixture of poly (ethylene oxide) and poly (propylene oxide) whose ends are blocked with an alkoxy group. The repeating unit of ethylene oxide and / or propylene oxide is preferably 3 to 50, more preferably 5 to 35. If the repeating unit is small, the compatibility with the resin is poor and the haze is increased, and if it is large, the water resistance may be lowered. When the above hydrophilic site is introduced, the carbodiimide compound becomes (1) cationic, (2) anionic, and (3) nonionic. Of these, nonionic properties that can be compatible with each other are preferable regardless of the ionicity of other water-soluble resins. Further, in order to improve the water resistance, it is preferable to have a nonionic property that does not require the introduction of an ionic hydrophilic group.

The carbodiimide compound is preferably contained in the protective layer in an amount of 5% by mass or more and 30% by mass or less. It is more preferably 10% by mass or more and 25% by mass or less, and further preferably 15% by mass or more and 20% by mass or less. If the content of the carbodiimide compound is less than 5% by mass, the cohesive force and water resistance of the protective layer may not be sufficiently improved. On the contrary, when the content is 30% by mass or more, the gas barrier property may be lowered, and the cohesive force of the protective layer may be lowered due to the increase of the uncrosslinked portion, and the hand cutting property may be deteriorated. ..

When the protective layer is formed by the resin composition for the protective layer, a coating liquid (coating liquid) composed of the polyurethane resin, ion-exchanged water, and a water-soluble organic solvent may be prepared, applied to the base film, and dried. As the water-soluble organic solvent, a single or mixed solvent selected from alcohols such as ethanol and isopropyl alcohol (IPA) and 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 a protective layer is not particularly limited as long as it is a method of coating the film surface to form a layer. For example, ordinary coating methods such as gravure coating, reverse roll coating, wire bar coating, and die coating can be adopted.

When forming the protective layer, it is preferable to apply the resin composition for the protective layer and then heat-dry it, and the drying temperature at that time is preferably 110 to 190 ° C, more preferably 130 to 190 ° C, still more preferable. Is 150-190 ° C. If the drying temperature is less than 110 ° C., the protective layer may be insufficiently dried, the protective layer may not be formed, the cohesive force and the water-resistant adhesiveness may be lowered, and as a result, the hand-cutting property may be lowered. On the other hand, if the drying temperature exceeds 190 ° C., the film may be overheated and the film may become brittle or shrink to deteriorate workability. In particular, by drying at 150 ° C. or higher, preferably 160 ° C. or higher, the film formation of the protective layer progresses effectively, and the adhesive area between the resin of the protective layer and the inorganic thin film layer becomes larger, so that the water resistance is improved. can do. Further, adding an additional heat treatment (for example, 150 to 190 ° C.) apart from drying is also more effective in advancing the film formation of the protective layer.

[Lamination with heat-sealing resin layer]
When the laminated film of the present invention is used as a packaging material, it is necessary to include a heat-sealing resin layer called a sealant. The heat-sealable resin layer is usually provided on the inorganic thin film layer side, that is, on the protective layer surface, but may also be provided on the outside of the base film (the surface opposite to the coating layer forming surface). The heat-sealing resin layer is usually formed by an extrusion laminating method or a dry laminating method. The thermoplastic polymer that forms the heat-sealable resin layer may be any as long as it can sufficiently exhibit sealant adhesiveness, and is a polyethylene resin such as HDPE, LDPE, LLDPE, a polypropylene resin, or an ethylene-vinyl acetate copolymer. , Ethethylene-α-olefin random copolymer, ionomer resin and the like can be used. The thickness of the heat-sealing 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. If the thickness is 20 μm or less, the productivity deteriorates. On the other hand, if it is 80 μm or more, the cost increases and the transparency also deteriorates.

[Other layers]
In the laminated film of the present invention, at least one layer or more of a printing layer, another plastic base material and / or a paper base material is laminated between or outside the inorganic thin film layer or the base film and the heat-sealing resin layer. You may have.

As the printing ink forming the printing layer, water-based and solvent-based resin-containing printing inks can be preferably used. Examples of the resin used for the printing ink include an acrylic resin, a urethane resin, a polyester resin, a vinyl chloride resin, a vinyl acetate copolymer resin, and a mixture thereof. Known printing inks include antistatic agents, light blocking agents, UV absorbers, plasticizers, lubricants, fillers, colorants, stabilizers, lubricants, defoamers, cross-linking agents, blocking agents, antioxidants and the like. Additives may be included. The printing method for providing the print layer is not particularly limited, and known printing methods such as an offset printing method, a gravure printing method, and a screen printing method can be used. For drying the solvent after printing, known drying methods such as hot air drying, hot roll drying, and infrared drying can be used.

On the other hand, as the other plastic base material or paper base material, paper, polyester resin, biodegradable resin and the like are preferably used from the viewpoint of obtaining sufficient rigidity and strength of the laminated body. Further, in order to obtain a film having excellent mechanical strength, a stretched film such as a biaxially stretched polyester film is preferable.

The laminated film of the present invention has an oxygen permeability of 5 ml / m2 · d · MPa or less under the condition of 23 ° C. × 65% RH, and exhibits good gas barrier properties. Further, by controlling the above-mentioned protective layer component / adhesion amount, it can be preferably 4 ml / m2 · d · MPa or less, more preferably 3 ml / m2 · d · MPa or less. When the oxygen permeability is 5 ml / m2 · d · MPa or more, it becomes difficult to cope with applications requiring high gas barrier properties.

The laminated film of the present invention preferably has a watered laminate strength of 1.5 N / 15 mm or more, more preferably 2.0 N / 15 mm or more, still more preferably 2.5 N / N / under conditions of 23 ° C. × 65% RH. It is 15 mm or more. If the laminating strength is 1.5 N / 15 mm or less, peeling may occur due to a bending load or the contents of the liquid, and the barrier property may be deteriorated or the contents may leak out. Further, there is a possibility that the hand-cutting property may be deteriorated.

Next, the present invention will be described in detail with reference to Examples and Comparative Examples, but the present invention is naturally not limited to the following Examples. Unless otherwise specified, "%" means "% by mass" and "part" means "part by mass".
The evaluation method used in the present invention is as follows.

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

(2) Oxygen permeability evaluation method For the laminated laminate A produced in (1) above, an oxygen permeability measuring device (MOCON's "OX-TRAN (registered trademark) 1 /" is based on the JIS-K7126 B method. 50 ”) was used to measure the oxygen permeability in an atmosphere of a temperature of 23 ° C. and a humidity of 65% RH. The oxygen permeability was measured in the direction in which oxygen permeates from the base film side of the laminated laminate to the heat-sealable resin layer (low density polyethylene) side.

(3) Evaluation method of laminate strength
The laminated laminate A produced in (1) above was cut into test pieces having 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, respectively, and the temperature was 23 ° C. The laminate strength was measured using a Tencilon universal material tester (“Tencilon UMT-II-500 type” manufactured by Toyo Baldwin Co., Ltd.) under the condition of a relative humidity of 65%. The lamination strength was measured at a tensile speed of 200 mm / min, and water was applied between the laminated film layer and the heat-sealing resin layer obtained in Examples and Comparative Examples to peel them off at a peeling angle of 90 degrees. The strength of the time was measured.

(4) Evaluation method of tear strength The laminated laminate A produced in (1) above is cut into a width of 25 mm and a length of 300 mm with respect to the width direction (TD direction) and the length direction (MD direction) of the base film, respectively. The tear strength was measured using a Tencilon universal material tester (“Tencilon UMT-II-500 type” manufactured by Toyo Baldwin Co., Ltd.) under the conditions of a temperature of 23 ° C. and a relative humidity of 65%. The tear strength was measured by setting the tear speed to 50 mm / min, making a 10 mm notch in the length direction at a width of 12.5 mm, and immersing the tear in water for 10 seconds immediately before the measurement.

(5) Hand-cutting property The laminated laminate A produced in (1) above was cut into a test piece having a width of 25 mm and a length of 300 mm, and a 10 mm notch was made in the length direction at a width of 12.5 mm immediately before measurement. After soaking in water for 10 seconds, it was torn by hand from the notch. At that time, those that could be easily torn without being caught were marked as hand-cutting ○, those that were partially caught but torn were marked as hand-cutting Δ, and those that could not be torn and the film stretched were marked as hand-cutting ×.

Each material used for forming the covering layer and the protective layer in each Example and Comparative Example was prepared as follows.

<Preparation of each material used for forming the coating layer or protective layer>
[Polyester resin (A)]
As the polyester resin, "AGN201" (solid content 25%) manufactured by Takemoto Oil & Fat Co., Ltd., which is a water-dispersible acrylic graft polyester resin containing self-crosslinking maleic anhydride as a graft chain, was prepared.

[Urethane resin (B)]
As the urethane resin, a commercially available dispersion of a urethane resin containing a metaxylylene group (“Takelac (registered trademark) WPB341” manufactured by Mitsui Chemicals, Inc .; solid content 30%) was prepared. The acid value of this urethane resin was 25 mgKOH / g, and the glass transition temperature (Tg) measured by DSC was 130 ° C. The ratio of aromatic or aromatic aliphatic diisocyanate to the total polyisocyanate component measured by 1H-NMR was 85 mol%.

[Silane Coupling Agent (C)]
As a silane coupling agent, a commercially available "(registered trademark) KBM603" manufactured by Shin-Etsu Chemical Co., Ltd .; 100% solid content) was prepared.

[Urethane resin (D)]
As the urethane resin, a commercially available polyester urethane resin dispersion (“Takelac (registered trademark) W605” manufactured by Mitsui Chemicals, Inc .; solid content 30%) was prepared. The acid value of this urethane resin was 25 mgKOH / g, and the glass transition temperature (Tg) measured by DSC was 100 ° C. The ratio of aromatic or aromatic aliphatic diisocyanate to the total polyisocyanate component measured by 1H-NMR was 55 mol%.

[Gas barrier ethylene-vinyl alcohol resin composition coating liquid (E)]
<Preparation of ethylene-vinyl alcohol copolymer solution>
Ethylene-vinyl alcohol copolymer (trade name: Soanol (registered trademark) V2603, manufactured by Nippon Synthetic Chemistry Co., Ltd., ethylene-vinyl acetate) 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 degree of saponification of a vinyl acetate component of about 100%, hereinafter abbreviated as EVOH), 15 parts are added, and a hydrogen peroxide solution having a concentration of 30% is added. 13 parts and 0.004 part of FeSO4 were added, and the mixture was heated to 80 ° C. with stirring and reacted for about 2 hours. Then, it was cooled and catalase was added so as to be 3000 ppm, and residual hydrogen peroxide was removed, whereby a substantially transparent ethylene-vinyl alcohol copolymer solution (EVOH solution) having a solid content of 15% was obtained.
<Preparation of inorganic layered compound dispersion>
Add 4 parts of montmorillonite (trade name: Kunipia (registered trademark) F, manufactured by Kunimine Industries, Ltd.), which is an inorganic layered compound, into 96 parts of purified water with stirring, and set the pressure to 50 MPa with a high-pressure disperser. Distributed. Then, the mixture was kept warm at 40 ° C. for 1 day to obtain an inorganic layered compound dispersion having a solid content of 4%.
<Additives>
Zirconium hydrochloride (manufactured by Daiichi Rare Element Chemical Industry Co., Ltd., trade name; Zircozol (registered trademark) ZC-20, solid content 20%)
<Preparation of coating liquid (E)>
31.75 parts of EVOH solution was added to 62.30 parts of the mixed solvent A (solvent composed of 40% purified water and 60% n-propyl alcohol), and the mixture was sufficiently stirred and mixed. Further, 5.95 parts of the inorganic layered compound dispersion was added to this solution while stirring at high speed. Three parts of the cation exchange resin was added to 100 parts of this mixed solution, and the mixture was stirred at a stirring speed of such that the ion exchange resin was not crushed for 1 hour to remove the cations, and then the cations were exchanged. Only the resin was filtered off with a strainer. The mixed solution obtained from the above operations was further dispersed in a high-pressure disperser at a pressure of 50 MPa, and then 0.75 parts of zirconium hydrochloride and 0.75 parts of the mixed solvent A2 were added to 97 parts of the dispersed mixed solution. Twenty-five parts were added, the mixture was stirred and stirred, and the mixture was filtered through a 255 mesh filter to obtain a coating liquid 3 for a protective layer having a solid content of 5%.

[Carbodiimide-based cross-linking agent (F)]
As a carbodiimide-based cross-linking agent, a commercially available "carbodilite (registered trademark) SV-02" manufactured by Nisshinbo Holdings (solid content 40%) was prepared.

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

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

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

30% water
Isopropanol 30%
Urethane resin (B) 40%

(3) Production of polyamide base film and coating of coating liquid 1 (lamination of coating layer)
Polycarbonate proamide was heated and melted at 260 ° C. using a screw extruder, extruded into a sheet from a T-die, and then this unstretched sheet was longitudinally stretched 3.3 times at 80 ° C. between a heating roll and a cooling roll. .. Then, the above-mentioned coating liquid 1 was applied to one side of the obtained uniaxially stretched film by the fountain bar coating method. Next, it was guided to a tenter, stretched 4.0 times laterally at 120 ° C., and then heat-fixed at 215 ° C. to form a 0.075 g / m ² coating layer on a biaxially stretched polyamide film having a thickness of 15 μm. A laminated film was obtained.

(4) Formation of Inorganic Thin Film Layer A composite oxide layer of silicon dioxide and aluminum oxide was formed as an inorganic thin film layer on the coating layer forming surface of the film obtained in (3) above by an electron beam vapor deposition method. As the vapor deposition source, 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. Further, 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. In this way, a thin-film film having a coating layer and an inorganic thin film layer was obtained.

(5) Coating of coating liquid 2 on thin-film vapor deposition film (lamination of protective layer)
The coating liquid 2 prepared in (2) above was applied onto the inorganic thin film layer of the vapor-filmed film obtained in (4) by the gravure roll coating method, and dried at 190 ° C. to obtain a protective layer. The coating amount after drying was 0.27 g / m ² (Dry).
As described above, a laminated film having a coating layer / an inorganic thin film layer / a protective layer on the base film was produced. As described above, the obtained laminated film was evaluated for oxygen permeability, laminating strength, tear strength, and hand-cutting property. The results are shown in Table 1.

(Examples 2 to 7, Comparative Examples 1 to 4)
In preparing the coating liquid for forming the protective layer, a laminated film was prepared in the same manner as in Example 1 except that the blending amount, adhesion amount and type of the resin were changed as shown in Table 1. Oxygen permeability, laminate strength, tear strength, and hand cutability were evaluated. The results are shown in Table 1.

According to the present invention, it has been found that a gas barrier laminated film provided with a coating layer, an inorganic thin film layer and a protective layer is excellent in gas barrier property and water resistance. As a result, peeling does not occur due to a bending load or water-based contents, and there is no problem that the barrier property is deteriorated or the contents leak out. In addition, from the results of tear strength and hand-cutting property, it was found that when the consumer cuts the film filled with the contents by hand, stress propagation is easy and sufficient hand-cutting property can be exhibited. Moreover, since the laminated film of the present invention can be easily manufactured with few processing steps, it is excellent in both economic efficiency and production stability, and it is possible to provide a gas barrier film having uniform characteristics.

Claims (3)

A coating layer, an inorganic thin film layer, and a protective layer are laminated in this order on at least one side of the polyamide base film with or without other layers, and are linearly formed via a polyurethane adhesive. A laminated laminate obtained by laminating a low-density polyethylene film, the coating layer containing a maleic anhydride-grafted polyester resin, the protective layer containing a urethane resin containing a metaxylylene group, and the laminated laminate. After being immersed in water for 10 seconds, the test force (P1) when the film is taken out of the water and torn by a tensile tester by 5 mm and the test force (P2) when the film is torn by 30 mm satisfy the following formula [1]. Laminate Laminated body.

The laminated laminate according to claim 1, wherein the protective layer contains at least one of a silicon-based cross-linking agent and a carbodiimide-based cross-linking agent. The laminated laminate according to claim 1 or 2, wherein the inorganic thin film layer is a layer made of a composite oxide of silicon oxide and aluminum oxide.