JP5258351B2 - Gas barrier biaxially oriented polyamide resin film - Google Patents

Description

  The present invention relates to a gas-barrier biaxially stretched polyamide resin film, and more particularly to a gas-barrier biaxially stretched polyamide resin film that can be used in applications that undergo high-temperature hot water treatment such as boil treatment and retort treatment.

  Biaxially stretched polyamide resin films such as nylon 6 and nylon 66 are excellent in mechanical properties such as tensile strength, pinhole strength, impact strength, and excellent in heat resistance and oil resistance. For this reason, for example, a laminated film in which a biaxially stretched polyamide resin film is used as a surface substrate and a sealant made of a polyolefin film is bonded to the surface substrate by a method such as dry lamination or extrusion lamination is used for retort food, konjac, boiled water, etc. Food, liquid soup, frozen foods, chilled foods, processed meat products, etc.

  However, since the biaxially stretched polyamide resin film generally has a high gas permeability such as oxygen, the contents are stored in the contents by a gas such as oxygen that has permeated the film while the contents are stored for a long time after being used as a packaging material. Alteration may occur.

  Therefore, polyvinylidene chloride (hereinafter, “PVDC”) is abbreviated on the surface of the biaxially stretched polyamide resin film. A laminated film in which a PVDC layer having a high gas barrier property is formed by coating an emulsion or the like is widely used for food packaging and the like. However, since PVDC generates an organic substance such as an acid gas during incineration, as the interest in the environment increases in recent years, there is a strong demand for shifting to other materials.

  As a material replacing PVDC, various types of barrier properties are imparted by coating polyvinyl alcohol (hereinafter abbreviated as “PVA”) and its modified products. However, it is extremely difficult to develop a barrier property under high humidity by using a water-soluble polymer, and the manufacturing conditions become severe, complicated, and adverse effects on quality associated therewith. There are many problems to be solved.

  For example, in Patent Documents 1 to 4, an excellent gas barrier coating film can be obtained by heat-treating a gas barrier coating composition comprising a composition obtained by partially neutralizing PVA and an ethylene-maleic acid copolymer with a specific metal salt. A further excellent gas barrier coating film can be obtained by heat-treating the gas barrier coating film thus obtained and the gas barrier coating film thus obtained in the presence of water or water containing a specific metal ion. It is described that In these patent documents, methods for heat treatment in the presence of water (or water containing a specific metal) include methods such as warm water immersion, warm water spray, storage under high humidity, and steam heating. In addition, a processing temperature of 90 ° C. or higher and a processing time of 1 minute or longer are preferred.

  However, in such a method, since the film coated with the gas barrier layer needs to be brought into contact with water for a relatively long time, it is expected that the production process becomes complicated and the productivity is lowered. Furthermore, since the film is greatly affected by heat and water absorption in the treatment process, for example, when a film with high water absorption such as polyamide is used as a base material, there is a concern about adverse effects on quality such as deformation and curling. The

  By the way, it is known that the biaxially stretched polyamide resin film is difficult to slip in a high humidity environment. In particular, the biaxially stretched polyamide resin film is excellent in pinhole strength, impact strength, and the like, so that it is often used as a substrate film for food packaging containing a large amount of moisture. Therefore, the use environment at the time of filling the contents is often a high-humidity environment, and troubles such as slip failure may occur at that time.

  Conventionally, as a method for improving the slipperiness of the biaxially stretched polyamide resin film, methods such as formation of surface protrusions by adding an inorganic filler, coating of a protrusion-forming substance on the film surface, addition of an organic lubricant, etc. have been tried. Yes. In particular, from the viewpoint of transparency and ink adhesion, in general, the combination of the addition of an inorganic filler and the addition of an organic lubricant improves the transparency, slipperiness, and printability. (Patent Document 5).

As described above, in the development of a gas-barrier biaxially stretched polyamide resin film, in view of its use, performance under high humidity, that is, barrier stability and slipperiness, are practically important. However, there is substantially no biaxially stretched polyamide resin film that has both barrier properties and slipperiness in an environment of high humidity, and can be stably used for applications that receive high-temperature hot water treatment such as boil treatment and retort treatment. .
Japanese Patent Laid-Open No. 2004-115776 JP 2004-137495 A JP 2004-136281 A JP 2004-322626 A JP-A-10-168310

  The present invention solves the above problems, has excellent slipperiness even in high humidity use environments, has excellent gas barrier properties even when stored for a long time under high temperature and high humidity, and high temperature such as boil treatment and retort treatment. It is an object of the present invention to provide a biaxially stretched polyamide resin film that can be stably used for applications that undergo hydrothermal treatment.

  As a result of intensive studies to solve the above problems, the inventors of the present invention are biaxially stretched containing silica and a long-chain fatty acid-based bisamide and having an extraction amount of caprolactam monomer of 0.1% by mass or less. A gas barrier layer formed by applying a gas barrier paint having a specific resin composition and heat treatment on a polyamide resin film substrate, an overcoat layer containing a specific metal compound, and a topcoat layer are sequentially laminated. Thus, the present inventors have found that a biaxially stretched polyamide resin film that has solved the above-mentioned problems can be obtained, and reached the present invention.

  That is, the gist of the present invention is as follows.

(1) It contains silica having an average particle diameter of 1 to 2 μm and a long-chain fatty acid-based bisamide composed of a fatty acid having 20 or more carbon atoms, and the extraction amount of caprolactam monomer is 0.1% by mass or less. An axially stretched polyamide resin film substrate;
A gas barrier layer formed of a paint for forming a gas barrier layer containing a polyalcohol-based polymer and a polycarboxylic acid-based polymer;
An overcoat layer formed of an overcoat layer-forming coating material containing at least one of a monovalent metal compound and a divalent or higher metal compound;
Including a top coat layer formed with a paint for forming a top coat layer,
The gas barrier layer is laminated directly or via an anchor coat layer, the overcoat layer is laminated on the gas barrier layer, and the top coat layer is laminated on the overcoat layer. A gas barrier biaxially stretched polyamide resin film characterized by

  (2) The gas barrier biaxially stretched polyamide resin film according to (1), wherein the coating material for forming the topcoat layer is an aqueous solution or an aqueous dispersion.

  (3) The gas barrier biaxially stretched polyamide resin film according to (1) or (2), wherein the overcoat layer-forming coating material is an organic solvent-based coating liquid.

  (4) The gas-barrier biaxial one of (1) to (3), wherein the polyalcohol-based polymer contains a polymer selected from polyvinyl alcohol and a copolymer of ethylene and vinyl alcohol. Stretched polyamide resin film.

  (5) A laminated film comprising the gas barrier biaxially stretched polyamide resin film of any one of (1) to (4) above in at least one layer.

  (6) A packaging bag obtained by bag-making the laminated film of (5).

  The gas barrier biaxially stretched polyamide resin film of the present invention has good workability at the time of filling contents in a high humidity environment, and is excellent in gas barrier properties under high humidity, and also boil treatment, retort treatment, etc. It can be used stably for applications that receive high temperature hot water treatment. Therefore, according to the gas-barrier biaxially stretched polyamide resin film of the present invention, a packaging bag having such performance can be obtained. Such a packaging bag can be used for packaging foods, pharmaceuticals, cosmetics, sundries, etc. It can be suitably used as a bag.

Hereinafter, the present invention will be described in detail.
<Gas barrier biaxially stretched polyamide resin film>
The gas barrier biaxially stretched polyamide resin film according to the present invention is:
Biaxially stretched polyamide containing silica having an average particle diameter of 1 to 2 μm and a long-chain fatty acid-based bisamide composed of a fatty acid having 20 or more carbon atoms and having an extraction amount of caprolactam monomer of 0.1% by mass or less A resin film substrate;
A gas barrier layer formed of a paint for forming a gas barrier layer containing a polyalcohol-based polymer and a polycarboxylic acid-based polymer;
An overcoat layer formed of an overcoat layer-forming coating material containing at least one of a monovalent metal compound and a divalent or higher metal compound;
Including a top coat layer formed with a paint for forming a top coat layer,
The gas barrier layer is laminated on the substrate directly or via an anchor coat layer, the overcoat layer is laminated on the gas barrier layer, and the top coat layer is laminated on the overcoat layer.

  By adopting such a configuration, according to the present invention, the workability at the time of filling the contents in a high humidity environment is good, and an excellent gas barrier property even if stored for a long time under high humidity. In addition, it is possible to produce a biaxially stretched polyamide resin film that can be stably used for high temperature hot water treatment such as boil treatment and retort treatment under milder conditions and more efficiently industrially. Can be provided in a way.

<Biaxially stretched polyamide resin film substrate>
The polyamide resin used for the film substrate used in the present invention has a structure mainly composed of nylon 6 or nylon 66 from the viewpoint of excellent mechanical properties and thermal properties and mainly used for packaging. Is preferred. Further, if necessary, a polyamide resin obtained by polycondensation such as a lactam having a three-membered ring or more, a polymerizable ω-amino acid, a dibasic acid and a diamine may be blended. Specifically, polymers such as ε-caprolactam, aminocaproic acid, enanthractam, 7-aminoheptanoic acid, 11-aminoundecanoic acid, 9-aminononanoic acid, α-pyrrolidone, α-piperidone; and hexamethylenediamine, nona Polycondensation of diamines such as methylenediamine, undecamethylenediamine, dodecamethylenediamine, and metaxylylenediamine; salts with dicarboxylic acids such as terephthalic acid, isophthalic acid, adipic acid, sebacic acid, dodecanedioic acid, and glutaric acid Examples thereof include polymers obtained by pre-loading, and copolymers thereof, such as nylon 4, 6, 7, 8, 11, 12, 6, 6, 6, 10, 6, 11, 6, 12, 6T, and the like.

  Silica contained in the polyamide resin is amorphous silicon dioxide and has an average particle diameter of 1 to 2 μm. Further, within this range, two types of silica having an average particle diameter may be used in combination. However, particularly when attention is paid to slipperiness under high humidity, the silica used mainly has an average particle diameter of 1 to 1.5 μm. Select. If the average particle size is less than 1 μm, the ability to form surface protrusions on the film is low, so that not only the slip property is not improved, but also the adhesion when a gas barrier layer is provided is inferior. When the average particle diameter exceeds 2 μm, the transparency is impaired, and the gas barrier layer cannot be uniformly coated on the substrate due to the protrusions formed of silica on the substrate, and sufficient barrier properties are not exhibited.

  That is, by adding a long-chain aliphatic bisamide compound, which will be described later, to the polyamide resin to improve its slipperiness, the hydrophilicity of the surface of the biaxially stretched polyamide resin film is lowered. The gas barrier biaxially stretched polyamide resin film of the present invention is a film in which a polyamide resin film surface is coated with a gas barrier layer-forming coating material containing a polyalcohol-based polymer. It can be a factor that inhibits the adhesion of the material. The addition of silica supplements the adhesion by forming protrusions on the film surface. However, if the surface protrusions are too large, the gas barrier properties are not exhibited although the adhesion is good. Therefore, it is important to use silica having an average particle diameter of 1 to 2 μm. The total amount of silica added is preferably 0.1 to 0.4% by mass.

  The long-chain aliphatic bisamide compound is contained in the polyamide resin in order to improve the slipperiness, but is required to be a bisamide composed of a fatty acid having 20 or more carbon atoms. Bisamides composed of fatty acids having less than 20 carbon atoms are sufficient for improving the slipperiness in the low humidity region, but are not sufficient for improving the slipperiness under the high humidity. Specific fatty acids having 20 or more carbon atoms include saturated fatty acids such as behenic acid (carbon number 22) and unsaturated fatty acids such as erucic acid (carbon number 22). As bisamides composed of these fatty acids, those that are generally commercially available include ethylene bisamides such as ethylene bisbehenamide, ethylenebiserucamide, hexamethylenebisbehenamide, hexamethylenebiserucamide, etc. Of hexamethylenebisamide. In particular, ethylene bisamide is preferable because it has an excellent effect of improving slipperiness under high humidity.

  The addition amount of the long-chain aliphatic bisamide is preferably 0.1 to 0.3% by mass. If it is less than 0.1% by mass, the effect of improving slipperiness under high humidity is poor, while if it exceeds 0.3% by mass, the adhesion between the obtained base film and the gas barrier layer is poor.

There is no restriction | limiting in particular in the method of adding a silica and fatty-acid bisamide to polyamide, The method used normally can be used.
Furthermore, in the present invention, the amount of caprolactam monomer extracted from the biaxially stretched polyamide resin film substrate needs to be 0.1% by mass or less. Preferably, it is 0.05 mass% or less, More preferably, it is 0.02 mass% or less. As described above, the adhesion between the film substrate and the gas barrier layer is improved by surface protrusions formed by adding silica having a specific average particle diameter, but during high-temperature hot water treatment such as boil treatment and retort treatment. However, in order to use it stably, it is necessary to make the extraction amount of the monomer from the film base fall within the above range.

  That is, at the time of the high-temperature hot water treatment, the monomer and the fatty acid bisamide are bleed out from the film base material, and the adhesion between the film base material and the gas barrier layer is lowered. Since fatty acid bisamide is an additive necessary for the expression of slipperiness under high humidity, it is also necessary to limit the amount of monomer in the film substrate in order to suppress a decrease in adhesion during high-temperature hot water treatment. When the extraction amount exceeds 0.1% by mass, the gas barrier film of the present invention is bonded to a sealant to form a packaging bag, and the packaging bag is filled with water-based contents to perform boil treatment or retort treatment. When performed, the adhesion between the film substrate and the gas barrier layer decreases due to the bleed-out component from the film substrate.

  The smaller the amount of monomer extraction, the better. However, the smaller the amount of monomer extraction, the longer the monomer removal step during film formation and the lower the productivity. For this reason, the lower limit is about 0.001 mass%.

  The monomer extraction amount of the base film in the present invention is measured and calculated by the following method. That is, about 0.5 g of a film cut into 0.5 cm square was carefully evaluated, extracted with 10 ml of distilled water in a boiling water bath (100 ° C.) for 2 hours, and the obtained extract was subjected to liquid chromatography. The amount of monomer extracted from the film is quantified (HP1100 HPLC system, manufactured by Hewlett-Packard Company). A more specific method for that will be described later.

  In the present invention, an antioxidant may be added to the base material in order to prevent a reduction in strength of the base material during high-temperature hot water treatment such as retort treatment. As the antioxidant, an antioxidant comprising a hindered phenol compound is preferable. As hindered phenol compounds, pentaerythrityl-tetrakis [3- (3,5-di-t-butyl-4-hydroxyphenyl) propionate], N, N′-hexamethylenebis (3,5-di-t -Butyl-4-hydroxy-hydrocinnamide), 1,3,5-trimethyl-2,4,6-tris (3,5-di-t-butyl-4-hydroxybenzyl) benzene, 1,6-hexane Diol-bis [3- (3,5-di-t-butyl-4-hydroxyphenyl) propionate], triethylene glycol-bis [3- (3,5-di-t-butyl-4-hydroxyphenyl) propionate ], Octadecyl-3- (3,5-di-t-butyl-4-hydroxyphenyl) propionate, and mixtures thereof. . Especially pentaerythrityl-tetrakis [3- (3,5-di-tert-butyl-4-hydroxyphenyl) propionate], N, N′-hexamethylenebis (3,5-di-tert-butyl-4-hydroxy -Hydrocinnamide) is preferable from the viewpoint of heat resistance, compatibility with polyamide resin, and safety and hygiene.

  In the present invention, it is possible to further increase the hot water resistance by using an organic phosphorus compound together with a hindered phenol antioxidant as an antioxidant in the base material. Tris (2,4-di-t-butylphenyl) phosphite, trisnonylphenyl phosphite, distearyl pentaerythritol-diphosphite, di (2,4-di-t-butylphenyl) as organophosphorus compounds -Pentaerythritol-diphosphite, di (2,6-di-t-butyl-4-methylphenyl) -pentaerythritol-diphosphite, and mixtures thereof can be exemplified. In particular, tris (2,4-di-t-butylphenyl) phosphite is preferable from the viewpoints of heat resistance, compatibility with polyamide resin, and safety and health.

  In the polyamide resin film substrate of the present invention, the content of the antioxidant is preferably in the range of 0.03 to 0.1% by mass. When the content is less than 0.03% by mass, the predetermined hot water resistance cannot be obtained, and when the content is more than 0.1% by mass, the hot water resistance is not further improved, and the slip property is deteriorated. In addition, when an antioxidant is a mixture of a hindered phenol type compound and an organic phosphorus type compound, it is preferable to set the mass ratio in the range of 2/1-1/2.

  Further, in the present invention, various additives and modifiers usually blended in the film, if necessary, in the polyamide resin film base, for example, heat stabilizer, ultraviolet absorber, light stabilizer, charging You may mix | blend an inhibitor, an antifogging agent, a crystal nucleating agent, a plasticizer, a crosslinking agent, a flame retardant, a coloring agent, etc.

  The polyamide resin thus adjusted is formed into a biaxially stretched polyamide resin film substrate as a base film in the present invention by forming the film by the following method.

  In general, for example, a polyamide resin composition is heated and melted with an extruder, extruded from a T-die into a film, and cooled on a cooling drum rotating by a known casting method such as an air knife casting method or an electrostatic application casting method. A film base material is obtained by solidifying to form an unstretched film and subjecting the unstretched film to a stretching treatment. If the unstretched film is oriented, the stretchability may be lowered in the subsequent step. Therefore, it is preferable that the unstretched film is substantially amorphous and non-oriented.

  The stretching process includes sequential biaxial stretching in which stretching is performed in the longitudinal direction and then stretching in the transverse direction, and simultaneous biaxial stretching in which stretching is performed simultaneously in the longitudinal and lateral directions. In any of the stretching methods, it is preferable to perform the stretching treatment so that the surface magnification is 9 times or more so that a surface orientation coefficient of 0.05 or more is obtained.

  The stretching method is not particularly limited, but the simultaneous biaxial stretching method is efficient in that it can perform melt film formation, monomer removal step, moisture adjustment step, stretching step, heat setting step, and cooling step in one step. This is desirable.

  The film subjected to the sequential biaxial stretching process or the simultaneous biaxial stretching process is heat-set at a temperature of 150 to 220 ° C. in the tenter subjected to the stretching process, and is 10% or less, preferably 2 to 2, as necessary. A longitudinal and / or lateral relaxation treatment is applied in the range of 6%.

  When producing the biaxially stretched polyamide resin film substrate used in the present invention, it is necessary to provide a monomer removing step at an arbitrary stage in the film forming step. Although it is an optional stage, the amount of monomer in the polyamide resin increases when the polyamide resin is melted. Therefore, the monomer removal step is preferably performed after the polyamide resin is melted and formed into a film. The monomer removal step may be performed at any of the stage of unstretched film, the stage after longitudinal stretching, and the stage after biaxial stretching, but it is performed at the stage of unstretched film in which the crystal and orientation of the film are not advanced. However, it is preferable because the monomer removal efficiency is high and the monomer is not released into the atmosphere during the stretching process.

The monomer removal step is carried out by bringing the polyamide film into contact with water at pH 6.5 to 9.0 and temperature 20 to 70 ° C. for 0.5 to 10 minutes under tension.
In the monomer removal step, the temperature of the water in the monomer removal tank needs to be 20 to 70 ° C. as described above, preferably 30 to 65 ° C., and more preferably 40 to 55 ° C. If the water temperature in the monomer removal tank is less than 20 ° C., it is difficult to remove the monomer in a short time. On the other hand, when the temperature exceeds 70 ° C., when the monomer removal step is performed at the stage of the unstretched film, wrinkles easily enter the unstretched film. When the film is stretched, the film may be cut, or troubles such as detachment of the film edge may occur, and the operability may deteriorate.

  The pH of the water in the monomer removal tank needs to be 6.5 to 9.0. Preferably it is 7.0-8.5, More preferably, it is 7.5-8.0. When the pH is less than 6.5, the oxidative degradation of the polyamide resin film proceeds. On the other hand, when the pH exceeds 9.0, alkaline water adheres to the film, so that the water is easily touched by an operator and is not preferable for safety.

  The time for which the polyimide resin film is in contact with water in the monomer removal step depends on the temperature and pH of the water, but it is necessary to be in the range of 0.5 to 10 minutes. Preferably it is 0.5-5 minutes, More preferably, it is 1-3 minutes. If it is less than 0.5 minutes, it is difficult to sufficiently remove the monomer. On the other hand, if it exceeds 10 minutes, the process becomes too long and the moisture content of the film during stretching becomes high.

  In the monomer removal, the water temperature, the pH of the water, and the contact time between the water and the film are closely related to each other. A higher water temperature is more effective for monomer removal. However, when the water temperature is increased, wrinkles easily enter the unstretched film. If the water temperature is set low, it takes time to remove the monomer and the productivity is deteriorated. By setting the pH to the weak alkali side of 6.5 to 9.0, the monomer in question can be selectively removed at a low temperature by a relatively short time treatment.

  Furthermore, when stretching is performed after the monomer removal step, in order to avoid troubles during stretching, after removing the monomer by treating the unstretched polyamide resin film in the monomer removal step, the moisture of the polyamide resin film in the moisture adjustment step It is preferable to stretch after the rate is 2 to 10% by mass, preferably 4 to 8% by mass. When the moisture content is lower than 2% by mass, stretching stress increases and troubles such as film cutting are likely to occur. On the other hand, when the moisture content is higher than 10% by mass, the thickness unevenness of the stretched film obtained by increasing the thickness unevenness of the unstretched film increases. In the moisture adjustment step, usually when the moisture content of the film is low, the film is passed through a moisture adjustment tank having a temperature of 40 to 90 ° C, more preferably a moisture adjustment tank having a temperature of 50 to 80 ° C, and the passage time is adjusted. Then, adjust the moisture content of the film. In the water adjustment tank, pure water is usually used. However, if necessary, the treatment liquid may contain a dye, a surfactant, a plasticizer, or the like. Moreover, you may adjust a water | moisture content by spraying water vapor | steam.

  On the other hand, when the moisture content of the film is higher than 10% by mass, the moisture content is lowered by bringing the film into contact with a roll having a water absorption layer.

  The biaxially stretched polyamide resin film of the present invention may be a single layer film or a laminated film by coextrusion or lamination.

  Hereinafter, the biaxially stretched polyamide resin film substrate may be simply referred to as “substrate”.

<Gas barrier layer>
The gas barrier layer is formed of a gas barrier layer-forming paint containing a polyalcohol polymer and a polycarboxylic acid polymer. A gas barrier layer having a dense cross-linked structure in which the polyalcohol-based polymer and the polycarboxylic acid-based polymer are cross-linked by an ester bond by applying a heat treatment after applying the gas barrier layer-forming coating to the surface of the substrate. Form.

  The blending ratio of the polyalcohol polymer and the polycarboxylic acid polymer is such that the molar ratio of the OH group of the polyalcohol polymer to the COOH group of the polycarboxylic acid polymer (OH group / COOH group) is 0.01 to 20. It is preferable that the molar ratio is 0.01 to 10, more preferably 0.02 to 5, and more preferably 0.04 to 2. It is most preferable to contain so that it may become. If the proportion of OH groups is less than the above range, the film-forming ability may be reduced. On the other hand, if the proportion of COOH groups is less than the above range, a crosslinked structure cannot be formed with a sufficient crosslinking density with a polyalcohol polymer, and gas barrier properties under a high humidity atmosphere can be sufficiently expressed. You may not be able to.

  The gas barrier layer-forming coating material is preferably an aqueous solution or an aqueous dispersion, and more preferably an aqueous solution, from the viewpoint of workability. Therefore, the polyalcohol polymer is preferably water-soluble, and the polycarboxylic acid polymer is also preferably water-soluble.

  The polyalcohol polymer is an alcohol polymer having two or more hydroxyl groups in the molecule, and examples thereof include polyvinyl alcohol, a copolymer of ethylene and vinyl alcohol, and the like.

  Polyvinyl alcohol and a copolymer of ethylene and vinyl alcohol preferably have a saponification degree of 95 mol% or more, and more preferably 98 mol% or more. Moreover, it is preferable that an average degree of polymerization is 50-4000, and it is more preferable that it is 200-3000.

  The above polyalcohol polymers can be used alone or in combination.

  The polycarboxylic acid polymer is a polymer containing a carboxyl group or an acid anhydride group obtained by polymerizing a monomer having a carboxyl group or an acid anhydride group and an ethylenically unsaturated double bond. As the monomer, those having an acryloyl group or a methacryloyl group (hereinafter referred to as “(meth) acryloyl group” together) as an ethylenically unsaturated double bond are preferable. For example, (meth) acrylic acid, 2-carboxyethyl (meth) acrylate, ω-carboxy-polycaprolactone mono (meth) acrylate, maleic acid, maleic anhydride, fumaric acid, fumaric anhydride, citraconic acid, citraconic anhydride, Itaconic acid, itaconic anhydride and the like can be mentioned. Of these, (meth) acrylic acid, maleic acid, maleic anhydride, itaconic acid, and itaconic anhydride are preferred.

  These monomers can be used alone or in combination of two or more, and can also be used in combination with other monomers. That is, as a polymer obtained by polymerizing monomers, a homopolymer (H) obtained by individually polymerizing these monomers, a copolymer (C1) obtained by copolymerizing a plurality of monomers, a monomer and other monomers. Examples thereof include a copolymer (C2) formed by copolymerization.

  As another monomer that can be copolymerized with the monomer, a monomer that does not have a carboxyl group or a hydroxyl group and that can be copolymerized with the monomer can be used as appropriate. For example, an esterified product of unsaturated monocarboxylic acid such as crotonic acid and (meth) acrylic acid, which has no hydroxyl group or carboxyl group; (meth) acrylamide, (meth) acrylonitrile, styrene, styrenesulfonic acid, vinyltoluene C2-C30 alpha olefins, such as ethylene, alkyl vinyl ethers, vinyl pyrrolidone, etc. are mentioned. These other monomers can also be used alone or in combination of two or more.

  The above-mentioned homopolymer (H), a copolymer of monomers (C1), and a copolymer of a monomer and another monomer (C2) can be used in any combination as the polycarboxylic acid polymer. For example, two or more homopolymers (H), two or more copolymers (C1) of monomers, or two or more copolymers (C2) of monomers and other monomers can be used. Alternatively, homopolymer (H) and copolymer (C1), homopolymer (H) and copolymer (C2), copolymer (C1) and copolymer (C2), homopolymer (H), copolymer (C2) and copolymer (C3) Such combinations can be used.

  As one of such polymers, an olefin-maleic acid copolymer can be preferably used, and an ethylene-maleic acid copolymer (hereinafter abbreviated as “EMA”) can be preferably used. This EMA can be obtained by copolymerizing maleic anhydride and ethylene by a known method such as solution radical polymerization.

  The maleic acid unit in EMA tends to have a maleic anhydride structure in which the adjacent carboxyl group is dehydrated and cyclized in a dry state, and opens to a maleic acid structure when wet or in an aqueous solution. Therefore, in this specification, unless otherwise specified, maleic acid units and maleic anhydride units are collectively referred to as maleic acid units. The maleic acid unit in EMA is preferably 5 mol% or more, more preferably 20 mol% or more, further preferably 30 mol% or more, and most preferably 35 mol% or more.

  The weight average molecular weight of EMA is preferably 1000 to 1000000, more preferably 3000 to 500000, still more preferably 7000 to 300000, and particularly preferably 10000 to 200000.

  Said polycarboxylic acid-type polymer can be used individually or in combination of 2 or more types, respectively.

  A crosslinking agent may be added to the gas barrier layer-forming coating material in order to promote the crosslinking reaction between the polyalcohol polymer and the polycarboxylic acid polymer to improve the gas barrier property.

  It is preferable that the addition amount of a crosslinking agent is 0.1-30 mass parts with respect to the total mass of 100 mass parts of a polyalcohol-type polymer and a polycarboxylic acid-type polymer, More preferably, it is 1-20 mass parts. . When the addition amount of the crosslinking agent is less than 0.1 parts by mass, a significant crosslinking effect cannot be obtained even when the crosslinking agent is added as compared to the case where the crosslinking agent is not added. Conversely, the crosslinking agent may inhibit the expression of gas barrier properties.

  The crosslinking agent may be a crosslinking agent having self-crosslinking properties, a compound having a plurality of functional groups that react with a carboxyl group and / or a hydroxyl group in the molecule, or a metal complex having a polyvalent coordination site. . For example, an isocyanate compound, a melamine compound, a urea compound, an epoxy compound, a carbodiimide compound, a zirconium salt compound and the like are preferable because they can exhibit excellent gas barrier properties. These crosslinking agents may be used in combination of multiple types.

  Alternatively, a catalyst can be added to the gas barrier layer-forming coating material in order to promote the crosslinking reaction and improve the gas barrier property.

  When a crosslinking agent or a catalyst is added, a crosslinking reaction by an ester bond is promoted between the polyalcohol-based polymer and the polycarboxylic acid-based polymer, and the gas barrier property of the resulting gas barrier layer can be further improved.

  Furthermore, the gas barrier layer-forming coating material has a heat stabilizer, an antioxidant, a reinforcing material, a pigment, an anti-degradation agent, a weathering agent, a flame retardant, a plasticizer, a release agent, and a lubricant, as long as the properties are not significantly impaired. Etc. may be added.

  Examples of the heat stabilizer, antioxidant, and deterioration inhibitor include hindered phenols, phosphorus compounds, hindered amines, sulfur compounds, copper compounds, alkali metal halides, and mixtures thereof.

  Examples of the reinforcing material include clay, talc, calcium carbonate, zinc carbonate, wollastonite, silica, alumina, magnesium oxide, calcium silicate, sodium aluminate, sodium aluminosilicate, magnesium silicate, glass balloon, carbon black, zinc oxide, Zeolite, hydrotalcite, metal fiber, metal whisker, ceramic whisker, potassium titanate whisker, boron nitride, graphite, glass fiber, carbon fiber and the like can be mentioned.

  Furthermore, an inorganic layered compound can also be added to the gas barrier layer-forming coating material in order to further enhance the gas barrier properties as long as the properties are not significantly impaired. The inorganic layered compound here refers to an inorganic compound in which unit crystal layers are overlapped to form a layered structure. Specific examples include zirconium phosphate (phosphate derivative type compound), chalcogenide, lithium aluminum composite hydroxide, graphite, clay mineral and the like. In particular, those that swell and cleave in a solvent are preferred.

  When preparing a coating that is an aqueous solution containing a mixture of a polyalcohol-based polymer and a polycarboxylic acid-based polymer, 0.1 to 20 equivalent% of an alkali compound with respect to the carboxyl group of the polycarboxylic acid-based polymer Is preferably added.

  A polycarboxylic acid polymer has a high hydrophilicity when it contains many carboxylic acid units, so it can be made into an aqueous solution without adding an alkali compound, but an appropriate amount of an alkali compound should be added. Thereby, the gas barrier property of the film obtained by applying the gas barrier layer-forming coating material is remarkably improved.

  The alkali compound is not particularly limited as long as it can neutralize the carboxyl group in the polycarboxylic acid-based polymer, and examples thereof include alkali metal and alkaline earth metal hydroxides, ammonium hydroxide, and organic ammonium hydroxide compounds. Of these, alkali metal hydroxides are preferred.

  The aqueous solution may be prepared by a known method using a dissolution vessel equipped with a stirrer. For example, a method in which a polyalcohol polymer and a polycarboxylic acid polymer are separately made into an aqueous solution and mixed before use is preferable. At this time, if the alkali compound is added to the aqueous solution of the polycarboxylic acid polymer, the stability of the aqueous solution can be improved.

  The polyalcohol-based polymer and the polycarboxylic acid-based polymer may be added simultaneously to the water in the dissolving kettle, but the solubility of the polycarboxylic acid-based polymer is better when the alkali compound is first added to the water.

  A small amount of alcohol or an organic solvent can be added to water for the purpose of increasing the solubility of the polycarboxylic acid polymer in water, for the purpose of shortening the drying process, or for improving the stability of the aqueous solution.

  The concentration of the gas barrier layer-forming coating material, that is, the solid content, can be appropriately changed according to the specifications of the coating apparatus and the drying / heating apparatus. However, if the solution is too dilute, it is difficult to form a layer having a sufficient thickness to exhibit gas barrier properties, and the subsequent drying process tends to take a long time. On the other hand, if the concentration of the paint is too high, it is difficult to obtain a uniform paint, and problems with paintability are likely to occur. From such a viewpoint, the concentration (solid content) of the coating is preferably in the range of 5 to 50% by mass.

  When forming a gas barrier layer from a gas barrier layer-forming coating material, first, the coating material is applied on a base material or an anchor coat layer formed on the base material. The coating method of the paint is not particularly limited, and for example, a usual method such as gravure roll coating, reverse roll coating, wire bar coating, air knife coating, or the like can be used.

  Immediately after applying the paint, heat treatment may be performed to form a dry coating film of the paint and heat treatment at the same time, or after application, moisture etc. may be evaporated by spraying hot air with a drier etc. Then, after forming a dry film, heat treatment may be performed. In consideration of shortening the process, etc., it is preferable to perform the heat treatment immediately after the coating unless there is a particular obstacle to the state of the gas barrier layer and physical properties such as gas barrier properties. The heat treatment method is not particularly limited, and it is generally considered that the heat treatment is performed in a dry atmosphere such as an oven. For example, the heat treatment may be performed in contact with a hot roll.

  When the base material is a stretched film, when the gas barrier layer is formed with the gas barrier layer forming paint, the paint may be applied to the stretched base material, or the paint may be applied to the base material before stretching. The film may be stretched after coating.

  In any of the above cases, the base material coated with the gas barrier layer-forming coating material is subjected to a heat treatment in a heated atmosphere at 100 ° C. or higher, so that the polyalcohol-based polymer and the polymer contained in the gas barrier layer-forming coating material are treated. Crosslinking reaction with the carboxylic acid-based polymer forms an ester bond, thereby forming a water-insoluble gas barrier layer.

  The preferred heat treatment temperature for forming the gas barrier layer is the ratio between the polyalcohol-based polymer and the polycarboxylic acid-based polymer, the presence or absence of other additive components, and the content, if any, of the additive components. Can also be affected, so I can not say unconditionally. However, it is preferably performed at a temperature of 100 to 300 ° C, more preferably 120 to 250 ° C, still more preferably 140 to 240 ° C, and particularly preferably 160 to 220 ° C. If the heat treatment temperature is too low, the crosslinking reaction between the polyalcohol-based polymer and the polycarboxylic acid-based polymer cannot sufficiently proceed, and it may be difficult to obtain a gas barrier layer having sufficient gas barrier properties. On the other hand, if the heat treatment temperature is too high, the coating may become brittle.

  The heat treatment time is preferably 5 minutes or less, usually 1 second to 5 minutes, preferably 3 seconds to 2 minutes, more preferably 5 seconds to 1 minute. If the heat treatment time is too short, the above-described crosslinking reaction cannot be sufficiently advanced, and it becomes difficult to obtain a gas barrier layer having gas barrier properties. On the other hand, when too long, productivity will fall.

  In the present invention, the gas barrier layer can be formed by forming a crosslinked structure by an ester bond between the polyalcohol-based polymer and the polycarboxylic acid-based polymer by the heat treatment for a relatively short time as described above.

  The thickness of the formed gas barrier layer is desirably thicker than 0.05 μm in order to sufficiently enhance the gas barrier property. On the other hand, the gas barrier layer exhibits excellent gas barrier properties under high temperature and high humidity by reacting with a monovalent metal compound and / or a bivalent or higher metal compound in the overcoat layer described later to form a crosslinked structure. To do. For this reason, when the thickness of the gas barrier layer is too thick, the metal crosslinking rate of the gas barrier layer is lowered, and the gas barrier property under high temperature and high humidity tends to be deteriorated.

  For this reason, the thickness of the gas barrier layer is preferably 0.05 to 3 [mu] m, more preferably 0.05 to 2 [mu] m, and particularly preferably 0.08 to 1 [mu] m. If the thickness of the gas barrier layer is less than 0.05 μm, it is difficult to form a layer having a uniform thickness. On the other hand, when the thickness exceeds 3 μm, the heat treatment time becomes long, and the productivity may be lowered.

<Anchor coat layer>
The anchor coat layer is used as necessary, is located between the base material and the gas barrier layer, and mainly plays a role in improving the adhesion of the gas barrier layer to the base material.

  As the coating agent used for the anchor coat layer, known ones can be used without particular limitation. For example, anchor coating agents such as isocyanate, polyurethane, polyester, polyethyleneimine, polybutadiene, polyolefin, and alkyl titanate are listed. Of these, isocyanate-based, polyurethane-based, and polyester-based anchor coating agents are preferable in consideration of the effects of the present invention. Furthermore, one or more mixtures and reaction products of isocyanate compounds, polyurethane and urethane prepolymers; mixtures and reaction products of one or more of polyesters, polyols and polyethers with isocyanates; or these A solution or dispersion of

  The anchor coating agent can also be applied to the substrate in the same manner as the method for applying the gas barrier layer-forming paint.

<Overcoat layer>
The overcoat layer is a resin layer formed on the surface of the gas barrier layer using a coating for forming an overcoat layer containing a monovalent metal compound and / or a divalent or higher metal compound.

This overcoat layer can be preferably formed by applying an overcoat layer-forming coating on the surface of the gas barrier layer and then heat-treating it.
The monovalent metal compound and / or divalent or higher metal compound in the overcoat layer reacts with the polyalcohol polymer or the polycarboxylic acid polymer in the gas barrier layer to form a crosslinked structure, thereby improving the gas barrier property. Remarkably improve. The cross-linked structure produced by the reaction of the monovalent metal compound and / or the divalent or higher metal compound and the polyalcohol polymer or polycarboxylic acid polymer may be an ionic bond or a covalent bond. It may be a potential bond.

  In the present invention, these metal compounds are contained in a resin and applied as a resin paint, followed by heat treatment. By carrying out like this, compared with the case where a metal compound is apply | coated as aqueous solution and it heat-processes, the outstanding gas barrier property and transparency can be provided industrially more efficiently and easily.

  Examples of the metal species used for the monovalent metal compound include Li, Na, K, Rb, and Se. Of these, Li, Na, and K are preferable, and Li is particularly preferable among them. The form of the metal compound to be used includes a simple metal, and includes inorganic salts such as oxides, hydroxides, halides, carbonates and sulfates, and organic acid salts such as carboxylates and sulfonic acids. Of these, hydroxides and carbonates are preferable.

  Examples of the metal species of the divalent or higher metal compound include Mg, Ca, Zn, Cu, Co, Fe, Ni, Al, and Zr. Of these, Mg, Ca, and Zn are preferable, and Mg and Ca are particularly preferable. The form of the metal compound to be used includes a simple metal, and includes inorganic salts such as oxides, hydroxides, halides, carbonates and sulfates, and organic acid salts such as carboxylates and sulfonic acids. Of these, oxides, hydroxides and carbonates are preferred.

  These metal compounds can be used alone or in combination of two or more. For example, a plurality of types of monovalent metal compounds and / or a plurality of types of divalent or higher metal compounds can be used.

  The mixing ratio of the metal compound in the overcoat layer-forming coating material varies greatly depending on the metal species used, the form of the compound, the type of resin constituting the overcoat layer-forming coating material, and the like. However, the blending ratio is 0.1 to 100 mass with respect to 100 mass parts of the solid content of the resin constituting the overcoat layer forming coating material (the total solid content of the resin and the crosslinking agent when the crosslinking agent is included). Part, preferably 0.5 to 80 parts by weight, more preferably 0.75 to 75 parts by weight, and most preferably 1 to 65 parts by weight. When the compounding amount of the metal compound is less than 0.1 parts by mass, the cross-linked structure formed by reaction with the polyalcohol polymer or polycarboxylic acid polymer in the gas barrier layer is decreased, and the gas barrier property may be lowered. is there. On the other hand, when a metal compound exceeds 100 mass parts, there exists a possibility that the adhesiveness of the overcoat layer formed, heat resistance, and water resistance may be impaired.

  The overcoat layer-forming coating material may be an organic solvent-based coating liquid (solution), an aqueous solution, or an aqueous dispersion. From the viewpoint of gas barrier properties, the overcoat layer-forming coating material is preferably an aqueous solution or an aqueous dispersion in order to promote ionization of the metal.

  However, on the other hand, when using a monovalent metal compound and / or a bivalent or higher metal compound having a relatively high solubility in water, an aqueous solution or an aqueous dispersion is formed from the overcoat layer-forming coating material. The water resistance of the overcoat layer may be reduced. Further, when a basic monovalent metal compound and / or a bivalent or higher metal compound is used, the stability of the overcoat layer-forming paint is determined when the overcoat layer-forming paint is an aqueous solution or an aqueous dispersion. And may reduce pot life.

  From the above, the overcoat layer-forming coating material is preferably an organic solvent-based coating liquid. Here, “organic solvent-based coating liquid” means that the solvent other than water is 90% by mass or more of the total solvent in the coating liquid, and more preferably 95% by mass or more. .

  As such a solvent other than water, a known organic solvent can be used. For example, toluene, methyl ethyl ketone (MEK), cyclohexanone, sorbeso, isophorone, xylene, methyl isobutyl ketone (MIBK), ethyl acetate, propyl acetate, butyl acetate, isopropyl alcohol (IPA) and the like can be mentioned. However, the organic solvent is not limited to these, and known organic solvents can be used alone or in admixture of two or more.

  The monovalent metal compound and / or the bivalent or higher metal compound is preferably used in the form of fine particles as much as possible at the time of mixing from the viewpoint of excellent transparency after the coating film is formed. Specifically, the average particle diameter is preferably 10 μm or less, more preferably 3 μm or less, and even more preferably 1 μm or less.

  Further, no matter how fine the particles are, if used as a suspension, it may cause precipitation during drying and poor appearance, so that it is preferably used as a fine particle dispersion in combination with a dispersant.

  In particular, Mg or Ca oxides, hydroxides, and carbonates that are effective as metal compounds having a valence of 2 or more are dispersed using a dispersant, so that the resin solids contained in the overcoat layer-forming coating material ( And when a crosslinking agent is contained, even if 65 parts by mass of the metal compound is added to 100 parts by mass of the total solid content of the resin and the crosslinking agent, a transparent coating film can be formed. A known thing can be used as a dispersing agent.

  There is no particular limitation on the method of mixing the metal compound (or its fine particle dispersion) in the overcoat layer-forming coating material. For example, the resin that forms the paint and the metal compound may be mixed and then dispersed using a disperser, or the metal compound may be dispersed in advance using a disperser and then mixed with the resin that forms the paint. May be.

  More specifically, for example, a method of mixing a solution in which a resin component contained in a paint is dissolved in a solvent such as an organic solvent and a solution in which a metal compound is dissolved and / or dispersed; A method in which a metal compound powder and / or a solution in which a metal compound is dissolved is mixed in an emulsion in which the resin component contained in the solvent is dispersed; after the resin and the metal compound are mixed by plasticizing by heat, a paint is obtained. Method: A method in which a metal compound powder is mixed in a solution in which a resin component contained in a paint for forming an overcoat layer is dissolved in a solvent or a dispersed emulsion, and the metal compound is dispersed using a disperser; Is dispersed in an arbitrary solvent using a disperser, and the resin component contained in the overcoat layer-forming paint is dissolved or dispersed in the solvent. A method of mixing the emulsion; and the like.

  Among them, a method of mixing a metal compound powder and / or a solution in which a metal compound is dissolved in an emulsion state in which a resin component constituting the overcoat layer forming coating material is dispersed in a solvent, and a metal compound in a solvent in advance. In order to make the dispersion of the metal compound relatively uniform, a method in which the resin component contained in the overcoat layer-forming coating material is dispersed in a solvent and a solution in which the resin component is dissolved in a solvent or a dispersed emulsion is mixed. preferable.

  Examples of the resin constituting the overcoat layer-forming coating material include various resins such as known urethane resins, polyester resins, acrylic resins, epoxy resins, alkyd resins, melamine resins, and amino resins. Among these, from the viewpoint of water resistance, solvent resistance, heat resistance, and curing temperature, urethane resin, polyester resin, and acrylic resin are preferable, and urethane resin is particularly preferable.

  A urethane resin is a polymer obtained by reaction of polyfunctional isocyanate and a hydroxyl-containing compound, for example. Specifically, polyfunctional isocyanates such as aromatic polyisocyanates such as tolylene diisocyanate, diphenylmethane isocyanate, polymethylene polyphenylene polyisocyanate, or aliphatic polyisocyanates such as hexamethylene diisocyanate, xylene isocyanate, polyether polyols, A urethane resin obtained by a reaction with a hydroxyl group-containing compound such as polyester polyol, polyacrylate polyol, or polycarbonate polyol can be used.

  These resins can be used alone or in admixture of two or more.

  As the polyester resin, a polyester polyol is preferable. Specific examples include polyester polyols obtained by reacting polyvalent carboxylic acids, dialkyl esters thereof, or mixtures thereof with glycols or mixtures thereof.

  Examples of the polyvalent carboxylic acid include aromatic polyvalent carboxylic acids such as isophthalic acid, terephthalic acid, and naphthalenedicarboxylic acid; and aliphatic polyvalent carboxylic acids such as adipic acid, azelaic acid, sebacic acid, and cyclohexanedicarboxylic acid.

  Examples of the glycol include ethylene glycol, propylene glycol, diethylene glycol, butylene glycol, neopentyl glycol, and 1,6-hexanediol.

  These polyester polyols preferably have a glass transition temperature (hereinafter referred to as “Tg”) of 120 ° C. or less, more preferably 100 ° C. or less, still more preferably 80 ° C. or less, and 70 ° C. The following are particularly preferred.

  Furthermore, the number average molecular weight of these polyester polyols is preferably from 1,000 to 100,000, more preferably from 2,000 to 50,000, and even more preferably from 3,000 to 40,000.

  In order to improve the water resistance, solvent resistance and the like of the overcoat layer to be formed, a crosslinking agent can be added to the overcoat layer-forming coating material. The crosslinking agent may be a crosslinking agent having a self-crosslinking property, a compound having a plurality of functional groups that react with a carboxyl group and / or a hydroxyl group in the molecule, or a metal complex having a polyvalent coordination site. Good. Among these, an isocyanate compound, a melamine compound, a urea compound, an epoxy compound, and a carbodiimide compound are preferable, and an isocyanate compound is particularly preferable.

  Specifically, aromatic polyisocyanates such as tolylene diisocyanate, phenylene diisocyanate, diphenylmethane diisocyanate, naphthalene diisocyanate, xylylene diisocyanate, polymethylene polyphenylene polyisocyanate; tetramethylene diisocyanate, hexamethylene diisocyanate, dodecamethylene diisocyanate, trimethylhexamethylene diisocyanate Aliphatic polyisocyanates such as cyclohexylene diisocyanate, isophorone diisocyanate, dicyclohexylmethane diisocyanate and xylene isocyanate; polyfunctional polyisocyanate compounds such as isocyanurates, burettes and allophanates derived from the above polyisocyanate monomers; or trimethylo Propane, may be mentioned polyfunctional polyisocyanate compounds such as reactive terminal isocyanate group-containing obtained by the trifunctional or more polyol compounds such as glycerin.

  The addition amount of the crosslinking agent is preferably 0.1 to 300 parts by mass, more preferably 1 to 100 parts by mass, and further preferably 3 to 50 parts by mass with respect to 100 parts by mass of the resin solid content contained in the paint. . When the addition amount of the crosslinking agent is less than 0.1 parts by mass, a significant crosslinking effect cannot be obtained even when the crosslinking agent is added as compared with the case where the crosslinking agent is not added. Conversely, the crosslinking agent may inhibit the expression of gas barrier properties.

  The overcoat layer-forming coating material is a solution or dispersion using water or an organic solvent as a medium. As described above, the overcoat layer-forming coating material is preferably an organic solvent-based coating liquid from the viewpoints of coating liquid stability, pot life, and water resistance. Therefore, it is preferable that the resin and the crosslinking agent constituting the coating material for forming the overcoat layer are soluble in an organic solvent, and in particular, a combination of a polyester polyol having a Tg of 70 ° C. or less and a polyisocyanate has a coating property, It is preferable from productivity and required physical properties.

  As long as the properties of the overcoat layer forming coating are not significantly impaired, heat stabilizers, antioxidants, reinforcing materials, pigments, deterioration inhibitors, weathering agents, flame retardants, plasticizers, mold release agents, lubricants, etc. May be included.

  Examples of the heat stabilizer, antioxidant, and deterioration inhibitor include hindered phenols, phosphorus compounds, hindered amines, sulfur compounds, copper compounds, alkali metal halides, and mixtures thereof.

  Examples of the reinforcing material include clay, talc, calcium carbonate, zinc carbonate, wollastonite, silica, alumina, magnesium oxide, calcium silicate, sodium aluminate, sodium aluminosilicate, magnesium silicate, glass balloon, carbon black, zinc oxide, Zeolite, hydrotalcite, metal fiber, metal whisker, ceramic whisker, potassium titanate whisker, boron nitride, graphite, glass fiber, carbon fiber and the like can be mentioned.

  The density | concentration (solid content) of the coating material for overcoat layer formation can be suitably changed with the specification of a coating device or a drying / heating apparatus. However, when the solution is too dilute, it reacts with the gas barrier layer, making it difficult to form a layer with sufficient thickness to exhibit gas barrier properties, and the subsequent drying process takes a long time. It is easy to produce. On the other hand, if the concentration of the paint is too high, it is difficult to obtain a uniform paint, and problems with paintability are likely to occur. From such a viewpoint, the concentration (solid content) of the paint is preferably in the range of 5 to 50% by mass.

  When forming the overcoat layer from the overcoat layer-forming coating material, after applying the coating material on the gas barrier layer formed on the substrate, heat treatment is immediately performed, and the formation of the dry film and the heat treatment are performed simultaneously. Alternatively, after the application, heat treatment may be performed after forming a dry film by evaporating moisture or the like by blowing hot air with a dryer or the like or irradiating infrared rays. In view of shortening of the process and the like, it is preferable to perform the heat treatment immediately after the coating, unless there are any particular obstacles to the state of the gas barrier layer and overcoat layer and physical properties such as gas barrier properties. The heat treatment method is not particularly limited, and it is generally considered that the heat treatment is performed in a dry atmosphere such as an oven. For example, the heat treatment may be performed in contact with a hot roll.

  The thickness of the overcoat layer formed on the gas barrier layer depends on the thickness of the gas barrier layer, but in order to develop gas barrier properties by reaction with the gas barrier layer, it is desirable that the thickness is at least 0.1 μm. From the viewpoint of productivity and cost, it is preferably 3 μm or less. Furthermore, 0.1-2 micrometers is more preferable and 0.15-1.5 micrometers is especially preferable.

  The method for applying the overcoat layer-forming paint is also not particularly limited, and usual methods such as gravure roll coating, reverse roll coating, wire bar coating, and air knife coating can be used.

  The preferred heat treatment temperature when forming the overcoat layer is influenced by the blending ratio of the metal compound and the resin, the presence or absence of other additive components, and the content of additive components when they are contained. However, it is preferably 50 to 300 ° C, more preferably 70 to 250 ° C, and particularly preferably 100 to 200 ° C. If the heat treatment temperature is too low, the thermal crosslinking reaction between the resin in the overcoat layer-forming coating material and the crosslinking agent cannot sufficiently proceed, and it is difficult to obtain sufficient adhesion, water resistance, and heat resistance. Or the action of the metal compound and the polyalcohol-based polymer and polycarboxylic acid-based polymer in the gas barrier layer cannot sufficiently proceed, and it may be difficult to impart sufficient gas barrier properties. On the other hand, if the heat treatment temperature is too high, wrinkles may occur due to film shrinkage or the coating may become brittle.

  The heat treatment time is preferably 5 minutes or less from the viewpoint of productivity, and is usually 1 second to 5 minutes, preferably 3 seconds to 2 minutes, more preferably 5 seconds to 1 minute. If the heat treatment time is too short, the above action cannot be sufficiently advanced, and it becomes difficult to obtain a film having adhesion, heat resistance, water resistance, and gas barrier properties.

<Topcoat layer>
The topcoat layer is a resin layer formed on the surface of the overcoat layer using the topcoat layer forming paint. This topcoat layer can be preferably formed by applying a topcoat layer-forming paint on the surface of the overcoat layer and then heat-treating it.

  A polyalcohol-based polymer and / or a polycarboxylic acid-based polymer in the gas barrier layer of a monovalent metal compound and / or a bivalent or higher metal compound in the overcoat layer by applying a coating for forming the topcoat layer and subsequent heat treatment. The reaction to the polymer can be promoted, whereby the gas barrier properties can be dramatically improved.

  The topcoat layer-forming coating material may be any of organic solvent-based coating liquid, aqueous solution, and aqueous dispersion. However, the monovalent metal compound and / or divalent or higher metal compound contained in the overcoat layer is ionized and reacted with the polyalcohol polymer and / or the polycarboxylic acid polymer in the gas barrier layer, and the metal is added to the gas barrier layer. In order to introduce cross-linking, the paint is preferably an aqueous solution or an aqueous dispersion.

Although it may vary depending on the coating conditions, it cannot be generally stated, but by applying a coating solution for forming the topcoat layer of an aqueous solution or aqueous dispersion and then heat-treating, the oxygen gas permeability is compared with the case without the topcoat layer. Thus, the gas barrier property can be improved by reducing it to about 1/2 to 1/4. For example, the oxygen gas permeability measured under the conditions of 20 ° C. and relative humidity 85% RH was about 102 to 110 ml / m ² · 24 h · MPa without the top coat layer, by providing the top coat layer , 50 ml / m ² · 24 h · MPa or less, and under favorable conditions, it can be further reduced to about 25 ml / m ² · 24 h · MPa.

  Furthermore, the top coat layer also has a role of protecting the overcoat layer.

  Examples of the resin contained in the paint for forming the top coat layer include various resins such as a known urethane resin, polyester resin, acrylic resin, epoxy resin, alkyd resin, melamine resin, and amino resin. Among these, from the viewpoint of water resistance, solvent resistance, heat resistance, and curing temperature, urethane resin, polyester resin, and acrylic resin are preferable, and polyester resin and urethane resin are particularly preferable. These resins can be used alone or in admixture of two or more.

  Examples of the urethane resin include a polymer obtained by a reaction between a polyfunctional isocyanate and a hydroxyl group-containing compound. Specifically, polyfunctional isocyanates such as aromatic polyisocyanates such as tolylene diisocyanate, diphenylmethane isocyanate and polymethylene polyphenylene polyisocyanate, or aliphatic polyisocyanates such as hexamethylene diisocyanate and xylene isocyanate; and polyether polyols And a urethane resin obtained by a reaction with a hydroxyl group-containing compound such as polyester polyol, polyacrylate polyol, and polycarbonate polyol.

  The polyester resin is preferably a polyester polyol, and examples thereof include a polyester polyol obtained by reacting a polyvalent carboxylic acid, a dialkyl ester thereof, or a mixture thereof with a glycol or a mixture thereof.

  Examples of the polyvalent carboxylic acid include aromatic polyvalent carboxylic acids such as isophthalic acid, terephthalic acid, and naphthalenedicarboxylic acid; and aliphatic polyvalent carboxylic acids such as adipic acid, azelaic acid, sebacic acid, and cyclohexanedicarboxylic acid.

  Examples of the glycol include ethylene glycol, propylene glycol, diethylene glycol, butylene glycol, neopentyl glycol, and 1,6-hexanediol.

  In order to improve the water resistance, solvent resistance, and the like of the formed topcoat layer, a crosslinking agent may be added to the topcoat layer-forming coating material. The crosslinking agent may be a crosslinking agent having self-crosslinking properties, a compound having a plurality of functional groups that react with a carboxyl group and / or a hydroxyl group in the molecule, a metal complex having a multivalent coordination site, etc. But you can. Of these, isocyanate compounds, melamine compounds, urea compounds, epoxy compounds, and carbodiimide compounds are preferable, and isocyanate compounds are particularly preferable.

  Specifically, aromatic polyisocyanates such as tolylene diisocyanate, phenylene diisocyanate, diphenylmethane diisocyanate, naphthalene diisocyanate, xylylene diisocyanate, polymethylene polyphenylene polyisocyanate; tetramethylene diisocyanate, hexamethylene diisocyanate, dodecamethylene diisocyanate, trimethylhexamethylene diisocyanate Aliphatic polyisocyanates such as cyclohexylene diisocyanate, isophorone diisocyanate, dicyclohexylmethane diisocyanate and xylene isocyanate; polyfunctional polyisocyanate compounds such as isocyanurates, burettes and allophanates derived from the above polyisocyanate monomers; or trimethylo Propane, may be mentioned polyfunctional polyisocyanate compounds such as reactive terminal isocyanate group-containing obtained by the trifunctional or more polyol compounds such as glycerin.

  It is preferable that the addition amount of a crosslinking agent is 0.1-300 mass parts with respect to 100 mass parts of resin solid content contained in the coating material for topcoat layer formation, 1-100 mass parts is more preferable, 3-50 Part by mass is more preferable.

The additive that can be added to the overcoat layer-forming paint described above can also be arbitrarily added to the topcoat layer-forming paint as well.
Although the density | concentration (solid content) of the coating material for topcoat layer formation can be suitably changed with the specification of a coating device or a drying / heating apparatus, it is preferable to set it as the range of 5-50 mass%. When forming the topcoat layer from the topcoat layer-forming coating material, it is preferable to perform a heat treatment immediately after applying the coating material.

  In consideration of shortening the process and improving productivity, it is preferable to form the topcoat layer continuously with the formation of the overcoat layer. That is, it is preferable to heat-treat both layers simultaneously after forming the topcoat layer following the formation of the overcoat layer.

  The heat treatment method for the topcoat layer is not particularly limited, and it is generally considered that the heat treatment is performed in a dry atmosphere such as an oven. Alternatively, for example, the heat treatment may be performed in contact with a heat roll.

  A preferable heat treatment temperature when forming the topcoat layer cannot be generally specified, but is preferably 50 to 300 ° C, more preferably 70 to 250 ° C, and particularly preferably 100 to 200 ° C. If the heat treatment temperature is too low, the thermal crosslinking reaction between the resin constituting the coating material and the crosslinking agent cannot be sufficiently advanced, and it becomes difficult to obtain sufficient adhesion, water resistance and heat resistance. On the other hand, if it is too high, wrinkles may occur due to film shrinkage or the coating may become brittle.

  The heat treatment time is preferably 5 minutes or less, usually 1 second to 5 minutes, preferably 3 seconds to 2 minutes, more preferably 5 seconds to 1 minute. If the heat treatment time is too short, the above action cannot be sufficiently advanced, and it becomes difficult to obtain a film having adhesion, heat resistance, water resistance, and gas barrier properties. On the other hand, when too long, productivity will fall.

  It is desirable that the thickness of the top coat layer is at least greater than 0.1 μm. However, from the viewpoint of productivity and cost, it is preferably 3 μm or less, more preferably 0.1 to 2 μm, and particularly preferably 0.15 to 1.5 μm.

The method for applying the topcoat-forming coating material is also not particularly limited, and a normal method similar to the method for applying the overcoat layer-forming coating material described above can be used.
In order for the metal compound contained in the overcoat layer to effectively act on the polyalcohol polymer and polycarboxylic acid polymer contained in the gas barrier layer, the gas barrier layer, the overcoat layer, and the topcoat layer are in direct contact with each other. It is important that Therefore, the base material, the gas barrier layer, the overcoat layer, and the topcoat layer need to be laminated in this order. As described above, an anchor coat layer may be included between the base material and the gas barrier layer.

<Laminate>
The gas barrier biaxially stretched polyamide resin film according to the present invention comprises (i) a laminate adhesive layer laminated directly on the surface of the topcoat layer or via a printing ink layer, and further heated on the surface. It can be set as the laminated body which laminated | stacked the sealing layer in order.

  Alternatively, (ii) a laminate adhesive layer is laminated directly on the surface of the substrate opposite to the surface on which the gas barrier layer is laminated or via a printing ink layer, and a heat seal layer is further formed on the surface. It can also be set as the laminated body laminated | stacked in order.

  However, the laminate (i) is preferable from the viewpoint of the scratch resistance and wear of the laminate. Further, in some cases, a functional layer such as a primer layer or an antistatic layer is provided between the topcoat layer and the laminate adhesive layer in (i) or between the substrate and the laminate adhesive layer in (ii). It may be formed. Alternatively, in order to improve the adhesion to the surface of the top coat layer and the laminate adhesive layer in (i) that are in contact with each other, or the surface of (ii) in which the substrate and the laminate adhesive layer are in contact with each other, Surface treatment such as treatment or ozone treatment may be performed.

<Printing ink layer>
A printing ink layer is a printing layer of ink, and is a character, a picture, etc. formed with ink. As inks, various pigments, extender pigments, and additives such as plasticizers, desiccants and stabilizers are added to ink binder resins such as urethane, acrylic, nitrocellulose, rubber, and vinyl chloride. Any ink can be used.

  As a method for forming the printing ink layer, for example, a known printing method such as an offset printing method, a gravure printing method, a silk screen printing method, or a known coating method such as roll coating, knife edge coating, or gravure coating may be used. it can.

<Laminate adhesive layer>
The laminate adhesive layer is a layer for improving the adhesion between the top coat layer in (i) and the base material in (ii) and the heat seal layer.

  A well-known thing can be used as a coating agent used in order to form a lamination adhesive bond layer. Examples of the coating agent include isocyanate, polyurethane, polyester, polyethyleneimine, polybutadiene, polyolefin, and alkyl titanate. Among these, in consideration of effects such as adhesion, heat resistance, and water resistance, isocyanate-based, polyurethane-based, and polyester-based coating agents are preferable. Furthermore, one or more mixtures and reaction products of isocyanate compounds, polyurethane and urethane prepolymers; mixtures and reaction products of one or more of polyesters, polyols and polyethers with isocyanates; or these A solution or dispersion of

  The thickness of the laminate adhesive layer is preferably greater than 0.1 μm in order to sufficiently enhance the adhesion of the heat seal layer, and is preferably about 10 μm or less from the viewpoint of productivity.

<Heat seal layer>
The heat seal layer is provided as a heat bonding layer when forming a bag-shaped packaging bag or the like, and a material capable of heat sealing, high frequency sealing, or the like is used. Examples of such materials include low density polyethylene, linear low density polyethylene, high density polyethylene, ethylene-vinyl acetate copolymer, polypropylene, ethylene-acrylic acid copolymer, ethylene-acrylate copolymer, An ethylene-acrylate copolymer etc. are mentioned. The thickness is determined according to the purpose, but is generally 15 to 200 μm.

  As a method for forming the laminate adhesive layer and the heat seal layer, a known method is used. For example, lamination methods such as dry lamination method, wet lamination method, solvent-free dry lamination method, extrusion lamination method; co-extrusion method in which two or more resin layers are simultaneously extruded and laminated; coating method in which a film is formed with a coater, etc. Can be mentioned. In view of adhesion, heat resistance, water resistance and the like, the dry lamination method is preferable.

  In order to improve the gas barrier property of the gas barrier property biaxially stretched polyamide resin film or the laminate using the same, they can be treated in a humidified atmosphere. By the humidification treatment, the action of the metal compound in the overcoat layer and the polyalcohol polymer and polycarboxylic acid polymer in the gas barrier layer can be further promoted. As such humidification treatment, these may be left in an atmosphere of high temperature and high humidity, or they may be directly brought into contact with high temperature water. The conditions of the humidification treatment vary depending on the purpose and the like, but when left in an atmosphere of high temperature and high humidity, a temperature of 30 to 130 ° C. and a relative humidity of 50 to 100% are preferable. Also when making it contact with high temperature water, the temperature of about 30-130 degreeC (100 degreeC or more is under pressure) is preferable. If the temperature is too low, the humidifying effect is not sufficient, and if the temperature is too high, the substrate may be thermally damaged. The humidifying treatment time varies depending on the treatment conditions, but generally a range of several seconds to several hundred hours is selected.

  The gas barrier biaxially stretched polyamide resin film of the present invention can be applied to various fields that require gas barrier properties and laminate strength after boil treatment. For example, it can be preferably used as various packaging materials, and is particularly suitable for the food packaging field.

  Hereinafter, the present invention will be specifically described with reference to examples and comparative examples. However, the present invention is not limited only to the following examples.

1. Evaluation method <Extraction amount of caprolactam monomer and cyclic dimer in film>
(Measurement sample adjustment)
0.5 g of the film cut into 0.5 cm square is carefully evaluated, taken into a 10 ml headspace bottle, added with 10 ml of distilled water, sealed with a butyl rubber stopper and an aluminum cap, and then placed in a boiling water bath (100 ° C.). Time extraction was performed. After cooling, the sample was filtered with a 0.45 μm disk filter.

(Calibration curve)
Caprolactam 0.1 g was dissolved in 100 ml of distilled water and further diluted to prepare a 100 ppm standard solution. A dimer having low solubility was prepared by dissolving 0.01 g in 100 ml of distilled water to prepare a standard solution. 1 to 10 μl of each solution was injected to obtain a calibration curve.

Apparatus: HP1100 HPLC system manufactured by Hewlett-Packard Company
Column: Waters Puresil 5μ C18 200 Angstrom 4.6 mm × 250 mm (40 ° C.)
Detector: UV210nm
Eluent: Methanol / water (volume ratio) = 35/75 solution for 12 minutes, then switch to methanol / water = (volume ratio) 100/0 solution over 3 minutes, 30 minutes, then over 5 minutes After switching to methanol / water (volume ratio) = 35/75 solution, the reaction was carried out for 20 minutes.

Flow rate: 0.7 ml / min
Injection amount: The unstretched film had a large amount of monomer, so that the amount was 10 μl. The stretched film had a small amount of monomer, and the amount was 50 μl.

    Detection limit: 3ppm

(Method of calculation)
Under the above conditions, the mass of the monomer and cyclic dimer in the sample was calculated from the monomer and cyclic dimer concentrations in the sample, and the value divided by the mass of the film was taken as the extraction amount (% by mass) of the monomer and cyclic dimer.

<Slipperiness>
As an index of slipperiness, the coefficient of static friction between the substrate surface and the substrate surface was measured according to JIS K7125 under conditions of a relative humidity of 65%, a temperature of 20 ° C., a relative humidity of 90%, and a temperature of 20 ° C.

<Oxygen gas barrier properties>
Using an oxygen barrier measuring instrument (OX-TRAN 2/20) manufactured by Mocon, oxygen permeability was measured and evaluated in an atmosphere at a temperature of 20 ° C. and a relative humidity of 85%.

<Strong laminate strength>
A test piece having a length of 100 mm and a width of 15 mm was prepared from the obtained laminate, and before and after the boil treatment at a peeling rate of 300 mm / min in an atmosphere at a temperature of 20 ° C. and a relative humidity of 65% by a T-type peeling test method. The laminate strength was measured. In addition, the boil process was performed by immersing the laminate test piece in 90 degreeC hot water for 30 minutes.

2. Production of Biaxially Stretched Polyamide Resin Film The silica and fatty acid bisamide used are as follows.

(1) Silica Silica Sea Hoster KE-P50 (manufactured by Nippon Shokubai Co., Ltd., average particle size 0.5 μm)
Silicia 310P (manufactured by Fuji Silysia Chemical Ltd., average particle size 1.4 μm)
Mizukasil P78A (Mizusawa Science Co., Ltd., average particle size 3.3 μm)

(2) Fatty acid bisamide Ethylene bis stearic acid amide (Nippon Kasei Co., Ltd., SLIPAX E, carbon number 18 of fatty acid)
Ethylene bisbehenamide (Nippon Kasei Co., Ltd., SLIPAX B, C22 of fatty acid)

<Manufacture of silica master chip>
A 30 liter autoclave was charged with 10 kg of ε-caprolactam, 1 kg of water, and 500 g of silica (Silicia 310P), maintained at 100 ° C., and stirred at that temperature until the reaction system became uniform. . Subsequently, the mixture was heated to 260 ° C. with stirring, maintained at a pressure of 1.5 MPa for 1 hour, released to normal pressure over an additional hour, and polymerized for an additional hour. When the polymerization was completed, the reaction product was discharged into a strand, cooled, solidified, and then cut to obtain a polyamide resin pellet. Subsequently, this pellet was refined with hot water at 95 ° C. for 8 hours to remove unreacted monomers and the like, and then dried. The relative viscosity of the obtained polyamide resin was 2.7.

Master chips using other silica were produced in the same manner.
<Manufacture of fatty acid master chip>
Nylon 6 resin (product name: A1030BRF, product name: A1030BRF, relative viscosity 2.7) is dry blended with 1% ethylenebisbehenamide (product name: SLIPAX B, Nippon Kasei Co., Ltd.). It was melt-kneaded with a 30 mm twin screw extruder set at 250 ° C., extruded into a strand, cooled, solidified, and then cut to obtain a master chip.

  A master chip using ethylenebisstearic acid amide was produced in the same manner.

<Base 1 to Base 6>
A silica master chip and a fatty acid bisamide master chip are extruded into nylon 6 resin (manufactured by Unitika Ltd., trade name: A1030BRF, relative viscosity 2.7) so that the silica particles and the fatty acid bisamide have the respective compounding amounts shown in Table 1. Each film is melted in a cylinder heated to a temperature of 270 ° C., extruded from a T-die orifice into a sheet shape, brought into close contact with a rotating drum cooled to 10 ° C., rapidly cooled, and each 150 μm thick unstretched film Got. The amount of monomer extracted from this unstretched film was as shown in Table 1.

  Next, the unstretched film was introduced into a monomer removal tank set to the temperature and pH shown in Table 1, and immersed in water for the time indicated in Table 1 as a monomer removal step. After that, after being guided to a moisture preparation tank at 60 ° C. and absorbing moisture so as to have a predetermined moisture content shown in Table 1, it is guided to a simultaneous biaxial stretching machine, 3.3 times in length and 3 in width. Simultaneous biaxial stretching was performed at a magnification of 0.0. Subsequently, heat treatment was performed at a temperature of 210 ° C., and a 5% relaxation treatment was performed in the transverse direction to obtain biaxially stretched polyamide resin film substrates 1 to 6 having a thickness of 15 μm. The monomer extraction amounts of these film substrates 1 to 6 were as shown in Table 1.

3. Provision of barrier properties <Production Example 1>
PVA (manufactured by Kuraray Co., Ltd., POVAL 105 (polyvinyl saponification degree 98 to 99%, average polymerization degree about 500)) was dissolved in hot water and then cooled to room temperature to obtain a PVA aqueous solution having a solid content of 15% by mass. .

<Production Example 2>
EMA (weight average molecular weight 60000, maleic acid unit 45-50%) and sodium hydroxide were dissolved in hot water and then cooled to room temperature, whereby 10 mol% of the carboxyl groups were neutralized with sodium hydroxide. An EMA aqueous solution having a solid content of 15% by mass was prepared.

<Production Example 3>
Polyester (Toyobo Co., Ltd., Byron GK130, film elongation 1000%, Tg 15 ° C., number average molecular weight 7000) was dissolved in a toluene / ethyl acetate / MEK mixed solvent (mass ratio 3/2/1), and the solid content was 15 mass. % Byron GK130 polyester solution was obtained.

<Production Example 4>
Dispersion in an amount of 25 parts by mass with respect to 100 parts by mass of magnesium oxide in a suspension toluene solution of magnesium oxide powder (average particle diameter 3.5 μm, crystal particle diameter 0.01 μm, BET specific surface area 145 m ² / g) An agent (decaglycerin oleate, HLB = 7) was added, and after stirring with a stirrer, the mixture was dispersed using a bead mill to obtain a magnesium oxide dispersion solution (1) having a solid content of 20% by mass.

<Production Example 5>
Dispersing agent in an amount of 35 parts by mass with respect to 100 parts by mass of magnesium oxide in a suspension of magnesium oxide powder (average particle size 3.5 μm, crystal particle size 0.01 μm, BET specific surface area 145 m ² / g) (Manufactured by San Nopco, sodium polyacrylate neutralized product, NOPCOSPERS 44C) was added, and after stirring with a stirrer, the mixture was dispersed using a bead mill to obtain a magnesium oxide dispersion aqueous solution (2) having a solid content of 20% by mass.

4). Examples and Comparative Examples <Example 1>
The PVA aqueous solution of Production Example 1 and the EMA aqueous solution of Production Example 2 are mixed so that the mass ratio (solid content) of PVA and EMA is 30/70, and a mixed liquid (for gas barrier layer formation) having a solid content of 10% by mass. Paint). On the base material 1 (thickness: 15 μm), the above mixed solution was coated with a bar coater No. 4 and dried at 80 ° C. for 2 minutes using an electric oven, followed by drying and heat treatment at 200 ° C. for 20 seconds using an electric oven to form a gas barrier layer having a thickness of 0.5 μm. .

  Further, the Byron GK130 polyester solution of Production Example 3 and the polyisocyanate compound (manufactured by Toyo Ink Manufacturing Co., Ltd., BX4773) are added to the magnesium oxide dispersion solution (1) of Production Example 4 and the mass ratio of magnesium oxide / polyester / polyisocyanate. In addition, a 1% by mass ethyl acetate solution of dioctyltin laurate (manufactured by Sankyo Gosei Co., Ltd., STANN SNT-1F) as a catalyst and toluene are mixed so as to be 20 / 83.3 / 16.7. Then, a mixed liquid (solid coat for forming an overcoat layer) having a solid content of 10% by mass was obtained.

  On the gas barrier layer described above, the overcoat layer-forming coating material is coated with a bar coater No. 4 and dried and heat-treated for 30 seconds at 80 using an electric oven to form an overcoat layer having a thickness of 0.7 μm.

Moreover, the liquid mixture (paint for topcoat layer formation) with a solid content of 7.5 mass% was obtained using aqueous polyurethane (Mitsui Takeda Chemical Co., Ltd., WS5100, 30 mass% aqueous solution).
On the above-described overcoat layer, the topcoat layer-forming paint is applied to the bar coater no. 6 and dried and heat-treated at 100 ° C. for 2 minutes using an electric oven to form a topcoat layer having a thickness of 0.7 μm.

  The laminated body obtained above was subjected to an aging treatment at 40 ° C. for 3 days to obtain a gas barrier biaxially stretched polyamide resin film in which the respective layers were laminated in the order of the base material, gas barrier layer, overcoat layer, and topcoat layer.

  Table 2 shows the measurement results of oxygen gas barrier property and slipperiness of this gas barrier property biaxially stretched polyamide resin film.

  On the surface of the top coat layer of the obtained gas barrier biaxially stretched polyamide resin film, a coating agent (TES4644 / TCS4645 manufactured by Toyo Morton Co., Ltd.) comprising a combination of a main agent (polyurethane resin) / curing agent (polyisocyanate resin), The laminate was applied with a dry laminator so as to have a dry film thickness of 3 μm to form a laminate adhesive layer. Further, a heat seal layer (manufactured by Tosero Co., Ltd., linear low density polyethylene, TUX-FCD, thickness 50 μm) is bonded onto the surface of the adhesive layer, and cured at 40 ° C. for 3 days to cure the adhesive layer. Thus, a laminate in which the layers were laminated in the order of the base material, the gas barrier layer, the overcoat layer, the topcoat layer, the laminate adhesive layer, and the heat seal layer was obtained. The results of measuring the laminate strength of this laminate are shown in Table 2.

<Example 2>
Compared to Example 1, the mass ratio of the magnesium oxide dispersion solution (1) forming the overcoat layer, Byron GK130 polyester solution and polyisocyanate compound BX4773 was determined as follows: Magnesium oxide / polyester / polyisocyanate = 50 / 83.3 / Changed to 16.7. Otherwise in the same manner as in Example 1, a gas barrier biaxially stretched polyamide resin film and a laminate were obtained.

  Table 2 shows the measurement results of the properties of the obtained gas-barrier biaxially stretched polyamide resin film and laminate.

<Example 3>
To the magnesium oxide dispersion aqueous solution (2) of Production Example 5, an aqueous polyurethane (manufactured by Mitsui Takeda Chemical Co., W635) and an aqueous dispersion of a polyisocyanate compound (manufactured by Nippon Kayaku Co., Ltd., Aquanate 100) are mixed with magnesium oxide. Was added so that the mass ratio of / polyurethane / polyisocyanate was 20 / 83.3 / 16.7 to obtain a mixed liquid (coating material for forming an overcoat layer) having a solid content of 10% by mass.

  Compared to Example 1, the use of the overcoat layer-forming coating material was different from the drying and heat treatment conditions during the formation of the overcoat layer at 120 ° C. for 2 minutes. Otherwise in the same manner as in Example 1, a gas barrier biaxially stretched polyamide resin film and a laminate were obtained.

  Table 2 shows the measurement results of the properties of the obtained gas-barrier biaxially stretched polyamide resin film and laminate.

<Example 4>
Compared with Example 1, the thickness of the gas barrier layer / overcoat layer / topcoat layer was changed to 0.3 μm / 0.4 μm / 0.4 μm by adjusting the solid content of the paint. Otherwise in the same manner as in Example 1, a gas barrier biaxially stretched polyamide resin film and a laminate were obtained.

  Table 2 shows the measurement results of the properties of the obtained gas-barrier biaxially stretched polyamide resin film and laminate.

<Example 5>
Compared with Example 2, the film thickness of the gas barrier layer / overcoat layer / topcoat layer was changed to 0.3 μm / 0.4 μm / 0.4 μm by adjusting the solid content of the paint. Otherwise in the same manner as in Example 2, a gas barrier biaxially stretched polyamide resin film and a laminate were obtained.

  Table 2 shows the measurement results of the properties of the obtained gas-barrier biaxially stretched polyamide resin film and laminate.

<Comparative Example 1>
Compared to Example 1, the substrate film was changed to the substrate 2. Otherwise in the same manner as in Example 1, a gas barrier biaxially stretched polyamide resin film and a laminate were obtained.

  Table 2 shows the measurement results of the properties of the obtained gas-barrier biaxially stretched polyamide resin film and laminate.

<Comparative example 2>
Compared to Example 1, the substrate film was changed to the substrate 3. Otherwise in the same manner as in Example 1, a gas barrier biaxially stretched polyamide resin film and a laminate were obtained.

  Table 2 shows the measurement results of the properties of the obtained gas-barrier biaxially stretched polyamide resin film and laminate.

<Comparative Example 3>
Compared to Example 4, the substrate film was changed to the substrate 3. Otherwise in the same manner as in Example 4, a gas barrier biaxially stretched polyamide resin film and a laminate were obtained.

  Table 2 shows the measurement results of the properties of the obtained gas-barrier biaxially stretched polyamide resin film and laminate.

<Comparative example 4>
Compared to Example 1, the substrate film was changed to the substrate 4. Otherwise in the same manner as in Example 1, a gas barrier biaxially stretched polyamide resin film and a laminate were obtained.

  Table 2 shows the measurement results of the properties of the obtained gas-barrier biaxially stretched polyamide resin film and laminate.

<Comparative Example 5>
Compared to Example 1, the magnesium oxide dispersion solution (1) of Production Example 4 was not included, and the Byron GK130 polyester solution of Production Example 3 and the polyisocyanate compound were, in mass ratio, polyester / polyisocyanate = 83.3 / 16. To obtain a mixed solution. Otherwise in the same manner as in Example 1, a gas barrier biaxially stretched polyamide resin film and a laminate were obtained.

  Table 2 shows the measurement results of the properties of the obtained gas-barrier biaxially stretched polyamide resin film and laminate.

<Comparative Example 6>
Compared to Example 1, no top coat layer was provided. Otherwise, in the same manner as in Example 1, a gas barrier biaxially stretched polyamide resin film in which the layers were laminated in the order of the substrate, gas barrier layer, and overcoat layer, and the substrate, gas barrier layer, overcoat layer, and laminate adhesive A laminate in which each layer was laminated in the order of the layer and the heat seal layer was obtained.

  Table 2 shows the measurement results of the properties of the obtained gas-barrier biaxially stretched polyamide resin film and laminate.

<Comparative Example 7>
Compared to Comparative Example 6, the magnesium oxide dispersion solution (1) was changed to only magnesium oxide powder. Otherwise, in the same manner as in Comparative Example 6, the gas barrier biaxially stretched polyamide resin film in which the layers were laminated in the order of the substrate, gas barrier layer, and overcoat layer, and the substrate, gas barrier layer, overcoat layer, and laminate adhesive A laminate in which each layer was laminated in the order of the layer and the heat seal layer was obtained.

  Table 2 shows the measurement results of the properties of the obtained gas-barrier biaxially stretched polyamide resin film and laminate.

<Comparative Example 8>
Compared to Example 1, the overcoat layer and the topcoat layer were not provided. Other than that, in the same manner as in Example 1, the gas barrier biaxially stretched polyamide resin film in which the layers were laminated in the order of the base material and the gas barrier layer, and the base material, the gas barrier layer, the laminate adhesive layer, and the heat seal layer in this order. A laminate in which each layer was laminated was obtained.

  Table 2 shows the measurement results of the properties of the obtained gas-barrier biaxially stretched polyamide resin film and laminate.

<Comparative Example 9>
Compared to Example 1, no overcoat layer was provided. Otherwise, in the same manner as in Example 1, the gas barrier biaxially stretched polyamide resin film in which the layers were laminated in the order of the substrate, the gas barrier layer, and the top coat layer, and the substrate, the gas barrier layer, the top coat layer, and the laminate adhesion A laminate in which each layer was laminated in the order of the agent layer and the heat seal layer was obtained.

  Table 2 shows the measurement results of the properties of the obtained gas-barrier biaxially stretched polyamide resin film and laminate.

<Comparative Example 10>
Compared to Example 1, the substrate film was changed to the substrate 5. Otherwise in the same manner as in Example 1, a gas barrier biaxially stretched polyamide resin film and a laminate were obtained.

  Table 2 shows the measurement results of the properties of the obtained gas-barrier biaxially stretched polyamide resin film and laminate.

<Comparative Example 11>
Compared to Example 1, the substrate film was changed to the substrate 6. Otherwise in the same manner as in Example 1, a gas barrier biaxially stretched polyamide resin film and a laminate were obtained.

  Table 2 shows the measurement results of the properties of the obtained gas-barrier biaxially stretched polyamide resin film and laminate.

  The gas-barrier biaxially stretched polyamide resin films of Examples 1 to 5 all had excellent sliding properties and gas barrier properties, and the laminate strengths obtained using the films were also excellent.

In contrast, in Comparative Example 1, the fatty acid constituting the fatty acid bisamide was stearic acid having 18 carbon atoms, so that the slipperiness under high humidity was not sufficient.
Since Comparative Examples 2 and 3 were too small with an average particle diameter of 0.5 μm, the slipperiness under high humidity was not sufficient, and the adhesion between the substrate and the gas barrier layer was inferior. . Moreover, since the average particle diameter of the silica of Comparative Example 4 was as large as 3.3 μm, the adhesion between the base material and the gas barrier layer was sufficient, but the barrier property was inferior.

In Comparative Examples 5 to 9, the predetermined overcoat layer and / or the topcoat layer did not exist, and thus sufficient gas barrier properties were not obtained.
Since Comparative Examples 10 to 11 used a film substrate with a monomer extraction amount exceeding 0.1% by mass, adhesion between the film substrate and the gas barrier layer in both cases before and after the boil treatment. Was inferior.

Claims (6)

Biaxially stretched polyamide containing silica having an average particle diameter of 1 to 2 μm and a long-chain fatty acid-based bisamide composed of a fatty acid having 20 or more carbon atoms and having an extraction amount of caprolactam monomer of 0.1% by mass or less A resin film substrate;
A gas barrier layer formed of a paint for forming a gas barrier layer containing a polyalcohol-based polymer and a polycarboxylic acid-based polymer;
An overcoat layer formed of an overcoat layer-forming coating material containing at least one of a monovalent metal compound and a divalent or higher metal compound;
Including a top coat layer formed with a paint for forming a top coat layer,
The gas barrier layer is laminated directly or via an anchor coat layer, the overcoat layer is laminated on the gas barrier layer, and the top coat layer is laminated on the overcoat layer. A gas barrier biaxially stretched polyamide resin film characterized by   The gas barrier biaxially stretched polyamide resin film according to claim 1, wherein the topcoat layer-forming coating material is an aqueous solution or an aqueous dispersion.   The gas barrier biaxially stretched polyamide resin film according to claim 1 or 2, wherein the overcoat layer-forming coating material is an organic solvent-based coating liquid.   The gas-barrier biaxially stretched polyamide according to any one of claims 1 to 3, wherein the polyalcohol-based polymer contains a polymer selected from polyvinyl alcohol and a copolymer of ethylene and vinyl alcohol. Resin film.   A laminated film comprising the gas barrier biaxially stretched polyamide resin film according to any one of claims 1 to 4 in at least one layer.   A packaging bag, wherein the laminated film according to claim 5 is made into a bag.