JP2015160330A - laminate - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a laminate comprising polyamide resin as base material, the laminate having excellent dyeing resistance, excellent productivity and economical efficiency, and excellent gas barrier properties under high humidity.SOLUTION: This invention provides a laminate characterized in that: a gas barrier laminate (III) comprises a gas barrier layer (II) comprising polycarboxylic acid and placed on polyamide resin base material (I) comprising a metal compound of 0.1-70 mass%; and a heat seal resin layer is placed on the gas barrier layer (II) side of the gas barrier laminate (III) directly or through an adhesive layer.

Description

  The present invention relates to a laminate based on a polyamide resin having excellent gas barrier properties and dyeing resistance under high humidity.

  Polyamide resin films are used in a wide range of applications as packaging materials because of their excellent strength, transparency, and moldability. However, since the polyamide resin film has high gas permeability such as oxygen, when used for packaging general food, retort processed food, cosmetics, medical supplies, agricultural chemicals, etc. The gas may cause alteration of the contents. Therefore, when used in these packaging applications, it is necessary to have gas barrier properties, and in packaging of foods containing moisture, gas barrier properties under high humidity are also required.

  On the other hand, it is known that a polyamide resin is a substance that is easily dyed and a polyester resin is a substance that is difficult to dye (for example, Patent Documents 1 and 2). The polyamide resin film is also easily dyed in the same way. Therefore, after filling the bag with a heat-seal resin layer on the polyamide resin film and filling it with dyeable contents and hydrothermal treatment, After long-term storage in a humidity environment, not only the heat-sealing resin layer but also the polyamide resin film is colored, which causes a problem that the appearance of the bag is impaired. Therefore, although a polyester film and a heat seal resin layer may be sequentially laminated on the polyamide resin film, there are problems that costs are increased and the number of lamination steps increases.

JP 2003-119376 A JP 2004-190147 A

  The object of the present invention is to provide a laminate based on a polyamide resin, which solves the above problems, has dye resistance, is excellent in productivity and economy, and has excellent gas barrier properties even under high humidity. There is.

As a result of intensive studies on the above problems, the present inventors have used a polyamide resin base material containing a specific amount of a metal compound, and on the gas barrier layer side of a laminate formed by laminating a gas barrier layer containing polycarboxylic acid. The inventors have found that a laminate characterized by laminating a heat sealing resin layer directly or via an adhesive layer has excellent gas barrier properties and dyeing resistance under high humidity, and have reached the present invention.
That is, the gist of the present invention is as follows.
(1) Gas barrier layer of gas barrier laminate (III) in which gas barrier layer (II) containing polycarboxylic acid is laminated on polyamide resin substrate (I) containing 0.1 to 70% by mass of metal compound (II) A laminate in which a heat sealing resin layer is laminated directly or via an adhesive layer on the side.
(2) The laminate according to (1), wherein the polyamide resin substrate (I) is a multilayer film, and at least one layer thereof contains 0.1 to 70% by mass of a metal compound.
(3) The metal compound contained in the laminate (4) polyamide resin substrate (I) according to either (1) or (2), wherein the gas barrier layer (II) contains a polyalcohol The metal which comprises is 1 type chosen from magnesium, calcium, and zinc, The laminated body in any one of (1)-(3) characterized by the above-mentioned.
(5) The gas permeability laminate (III) has an oxygen permeability of 300 ml / (m ² · day · MPa) or less in an atmosphere at 20 ° C. and a relative humidity of 65% after hydrothermal treatment at 95 ° C. for 30 minutes. The laminate according to any one of (1) to (4), wherein
(6) The laminate according to any one of (1) to (5), wherein the gas barrier laminate (III) is simultaneously or sequentially biaxially stretched.
(7) The laminate according to any one of (1) to (6), wherein the polyamide resin substrate (I) contains a pigment.
(8) The laminate according to any one of (1) to (7), wherein the pigment contained in the polyamide resin substrate (I) is a white pigment.
(9) A packaging bag or container, wherein the laminate according to any one of (1) to (8) is used, and a heat seal resin layer is disposed on the content side.

ADVANTAGE OF THE INVENTION According to this invention, while having dyeing resistance, it can provide the laminated body based on a polyamide resin which is excellent in productivity and economical efficiency, and has the outstanding gas barrier property under high humidity.
Since the obtained gas barrier laminate has excellent gas barrier properties and dyeing resistance under high humidity, a heat seal resin layer is laminated on the gas barrier layer directly or through an adhesive layer to form a packaging bag or container. It is possible to prevent the polyamide resin base material from being dyed after filling with dyeable contents, after hot water treatment, or after long-term storage in a high temperature / high humidity environment.
Further, in the present invention, the polyamide resin base material containing a metal compound can be produced simply by adding the metal compound to the raw material of the polyamide resin base material, so that it is an industrial merit from the viewpoint of productivity and cost. Is extremely large.

Hereinafter, the present invention will be described in detail.
The laminate of the present invention is obtained by laminating a heat barrier resin layer on a gas barrier laminate (III) in which a gas barrier layer (II) is laminated on a polyamide resin substrate (I). ) Needs to contain a metal compound.

  The metal constituting the metal compound is not particularly limited, and monovalent metals such as lithium, sodium, potassium, rubidium, and cesium, and magnesium, calcium, zirconium, zinc, copper, cobalt, iron, nickel, aluminum, and the like. A bivalent or higher metal is mentioned. Among them, a metal having a high ionization tendency is preferable from the viewpoint of easy reaction with carboxylic acid, and a monovalent or divalent metal is preferable from the viewpoint of gas barrier properties. Specifically, lithium, sodium, potassium, magnesium, calcium, and zinc are preferable, and magnesium, calcium, and zinc are more preferable. The type of metal is not limited to one type, and may be two or more types.

  In the present invention, the metal compound is a compound containing the above metal, and examples of the compound include oxides, hydroxides, halides, inorganic salts such as carbonates, bicarbonates, phosphates, sulfates, Examples thereof include carboxylate such as acetate, formate, stearate, citrate, malate and maleate, and organic acid salt such as sulfonate, and is preferably an oxide or carbonate. . Moreover, you may use a metal simple substance as a metal compound.

  Among the above metal compounds, preferred examples include lithium carbonate, sodium hydrogen carbonate, magnesium oxide, magnesium carbonate, magnesium hydroxide, magnesium acetate, calcium oxide, calcium carbonate, calcium hydroxide, calcium chloride, calcium phosphate, calcium sulfate, acetic acid. Calcium, zinc acetate, zinc oxide, zinc carbonate can be mentioned, and from the viewpoint of gas barrier properties, magnesium salts such as magnesium oxide, magnesium carbonate, magnesium hydroxide, magnesium acetate, calcium carbonate, calcium acetate, zinc oxide, Divalent metal compounds such as zinc acetate are preferred. From the viewpoint of the transparency of the polyamide resin substrate (I), monovalent compounds such as lithium carbonate and sodium hydrogen carbonate, magnesium oxide, magnesium carbonate, and magnesium hydroxide Magnesium salts such as Siumu is preferable. These may be used alone or in combination of two or more.

  The metal compound is preferably in a powder form, and the average particle diameter is not particularly limited, but is preferably 0.001 to 10.0 μm, more preferably 0.005 to 5.0 μm, and 0 0.01 to 2.0 μm is more preferable, and 0.05 to 1.0 μm is particularly preferable. Since the haze of the polyamide resin substrate (I) can be reduced, the metal compound preferably has a smaller average particle diameter. However, a metal compound having an average particle size of less than 0.001 μm has a large surface area, so that it easily aggregates, and coarse aggregates are scattered in the film, which may deteriorate the mechanical properties of the substrate. On the other hand, the polyamide resin base material (I) containing a metal compound having an average particle size exceeding 10.0 μm tends to be broken when the film is formed, and the productivity tends to decrease.

  A metal compound can improve dispersibility, weather resistance, wettability with a thermoplastic resin, heat resistance, transparency, and the like by performing surface treatment such as inorganic treatment or organic treatment. Examples of the inorganic treatment include alumina treatment, silica treatment, titania treatment, zirconia treatment, tin oxide treatment, antimony oxide treatment, and zinc oxide treatment. Examples of the organic treatment include treatment using a fatty acid compound, a polyol compound such as pentaerythritol and trimethylolpropane, an amine compound such as triethanolamine and trimethylolamine, a silicone compound such as a silicone resin and alkylchlorosilane. .

  The content of the metal compound in the polyamide resin substrate (I) is required to be 0.1 to 70% by mass, preferably 0.1 to 50% by mass, and 0.2 to 20% by mass. % Is more preferable, and 0.2 to 5% by mass is even more preferable. From the viewpoint of haze, it is preferably less than 5% by mass. When the content of the metal compound in the polyamide resin substrate (I) is 0.1 to 70% by mass, the resulting gas barrier laminate (III) can obtain excellent gas barrier properties. However, if the content of the metal compound in the polyamide resin substrate (I) is less than 0.1% by mass, the number of cross-linked structures formed by reacting with the polycarboxylic acid in the gas barrier layer (II) is reduced. The resulting gas barrier laminate (III) has a reduced gas barrier property. On the other hand, the polyamide resin base material (I) having a content exceeding 70% by mass has a high frequency of breakage in stretching during film formation, and the productivity tends to be lowered, and the mechanical properties are also likely to be lowered.

  The method for incorporating the metal compound into the polyamide resin substrate (I) is not particularly limited, and the polyamide resin substrate (I) can be blended at any point in the production process. For example, a method of adding a metal compound when polymerizing a thermoplastic resin constituting the polyamide resin substrate (I), a method of kneading a thermoplastic resin and a metal compound with an extruder, a high concentration of the metal compound A method (masterbatch method) in which a masterbatch kneaded and blended is prepared and added to a thermoplastic resin to dilute it is exemplified. In the present invention, the master batch method is preferably employed.

  In the present invention, examples of the polyamide resin include polyamide resins such as nylon 6, nylon 66, nylon 46, nylon MXD6, and nylon 9T, or a mixture thereof.

  The polyamide resin, if necessary, within a range that does not adversely affect the performance of the polyamide resin substrate (I), a heat stabilizer, an antioxidant, a reinforcing material, a pigment, a deterioration inhibitor, a weathering agent, a flame retardant, You may add 1 type, or 2 or more types of various additives, such as a plasticizer, antiseptic | preservative, a ultraviolet absorber, an antistatic agent, and an antiblocking agent. In addition, inorganic particles other than metal compounds and organic lubricants may be added to the thermoplastic resin for the purpose of improving the slip property of the polyamide resin base material (I), and among them, silica may be added. Is preferred.

  The thickness of the polyamide resin substrate (I) can be appropriately selected according to the mechanical strength required for the obtained gas barrier laminate (III). For reasons of mechanical strength and ease of handling, the thickness of the polyamide resin substrate (I) is preferably 5 to 100 μm, and more preferably 10 to 30 μm. If the thickness of the polyamide resin substrate (I) is less than 5 μm, sufficient mechanical strength cannot be obtained, and the piercing strength tends to deteriorate.

  The polyamide resin substrate (I) may be a single-layer film or a multi-layer film. When the polyamide resin substrate (I) is a multilayer film, it is necessary that at least one layer thereof contains 0.1 to 70% by mass of a metal compound. Hereinafter, a layer containing 0.1 to 70% by mass of a metal compound in a multilayer film or a single layer film is referred to as a “metal-containing layer (M)”, and other than the “metal-containing layer (M)” in the multilayer film. This layer may be referred to as “polyamide resin layer (R)”.

When the polyamide resin substrate (I) is a multilayer film, the structure of the obtained gas barrier laminate (III) includes a gas barrier layer (II) and a metal-containing layer (M) of the polyamide resin substrate (I). Are in contact, (R) / (M) / (II), (M) / (R) / (M) / (II), (II) / (M) / (R) / (M ) / (II). Since these structures are such that the gas barrier layer (II) and the metal-containing layer (M) are in contact with each other, the polycarboxylic acid in the gas barrier layer (II) and the metal compound in the metal-containing layer (M) are likely to react. Gas barrier properties can be obtained efficiently. Among these, in consideration of equipment for manufacturing and operability, the configuration of (R) / (M) / (II) is preferable.
Further, the gas barrier layer (II) and the polyamide resin layer (R) are in contact, (M) / (R) / (II), (R) / (M) / (R) / (II), (II) / (R) / (M) / (R) / (II) and the like. Among these, the structure of (M) / (R) / (II) is preferable in consideration of equipment for manufacturing and operability.

  The thickness constitution ratio of the metal-containing layer (M) and the polyamide resin layer (R) constituting the multilayer film is not particularly limited, and the total thickness (Mt) of the metal-containing layer (M) and the resin layer (R) The ratio of the total thickness (Rt) ((Rt) / (Mt)) is preferably 1/1000 to 1000/1, and the thickness control of each layer is easy, so 1/100 to 100/1. It is more preferable that it is 1/10 to 10/1.

  The above additives may be added to the polyamide resin layer (R), and the polyamide resin layer (R), which is the outermost layer of the gas barrier laminate (III), may be silica or the like for the purpose of improving the slip property. Is preferably added.

  In the present invention, the polyamide resin substrate (I) may contain a pigment. In the case of a multilayer film, the polyamide resin layer (R) or the metal-containing layer (M) may contain a pigment. Although the kind of pigment is not particularly limited, a gas barrier laminate (III) having suitable whiteness and concealment can be obtained by containing a white pigment. In the case of a white film, when it is dyed, the degree of appearance defect may appear strongly. Therefore, in the present invention, when the polyamide resin substrate (I) containing a white pigment is used, the effect of dyeing resistance is more remarkable.

  There is no restriction | limiting in particular in the white pigment used for this invention, The white pigment normally used for coloring of a plastic is used. Preferable white pigments include, for example, titanium oxide, barium sulfate, zinc oxide, antimony trioxide, zinc sulfide and the like, and these may be used in appropriate combination. Particularly preferred white pigments include titanium oxide that can be whitened with a small amount of addition. The particle size of the white pigment is usually 0.1 to 1.0 μm, particularly about 0.1 to 0.5 μm.

  The gas barrier layer (II) constituting the gas barrier laminate (III) needs to contain a polycarboxylic acid. The polycarboxylic acid in the gas barrier layer (II) can exhibit gas barrier properties and dyeing resistance by reacting with the metal compound in the polyamide resin substrate (I).

The polycarboxylic acid in the present invention is a compound or polymer having two or more carboxyl groups in the molecule, and these carboxyl groups may form an anhydride structure.
Specific examples of the polycarboxylic acid include 1,2,3,4-butanetetracarboxylic acid, polyacrylic acid, polymethacrylic acid, acrylic acid-methacrylic acid copolymer, acrylic acid-maleic acid copolymer, polymaleic acid Examples thereof include olefin-maleic acid copolymers such as ethylene-maleic acid copolymers, polysaccharides having a carboxyl group in the side chain such as alginic acid, polyamides containing carboxyl groups, and polyesters. The above polycarboxylic acids can be used alone or in combination of two or more.

  When the polycarboxylic acid is a polymer, the weight average molecular weight is preferably 1,000 to 1,000,000, more preferably 10,000 to 150,000, and more preferably 15,000 to 1,000,000. More preferably, it is 110,000. If the weight average molecular weight of the polycarboxylic acid is too low, the resulting gas barrier layer (II) becomes fragile. On the other hand, if the molecular weight is too high, the handling properties are impaired, and in some cases, the gas barrier layer (II) described later is used. The gas barrier layer (II) obtained by agglomeration in the coating liquid for forming may have a gas barrier property impaired.

In the present invention, among the above polycarboxylic acids, polyacrylic acid and olefin-maleic acid copolymer, particularly ethylene-maleic acid copolymer (hereinafter, sometimes abbreviated as EMA) are from the point of gas barrier property. Preferably used. EMA is obtained by polymerizing maleic anhydride and ethylene by a known method such as solution radical polymerization.
The maleic acid unit in the olefin-maleic acid copolymer tends to have a maleic anhydride structure in which the adjacent carboxyl group is dehydration-cyclized in a dry state, and opens to form a maleic acid structure when wet or in an aqueous solution. Therefore, in the present invention, 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. .
Further, the weight average molecular weight of EMA is preferably 1,000 to 1,000,000, more preferably 3,000 to 500,000, and further preferably 7,000 to 300,000. It is preferably 10,000 to 200,000.

In the present invention, the gas barrier layer (II) preferably contains a polyalcohol. By containing the polyalcohol, the polycarboxylic acid in the gas barrier layer (II) reacts with the polyalcohol in addition to reacting with the metal compound in the polyamide resin substrate (I), so the gas barrier property is improved. can do.
Polyalcohol is a compound having two or more hydroxyl groups in the molecule, and low molecular weight compounds include sugar alcohols such as glycerin and pentaerythritol, monosaccharides such as glucose, disaccharides such as maltose, and oligosaccharides such as galactooligosaccharides. Examples of the polymer compound include polysaccharides such as polyvinyl alcohol, ethylene-vinyl alcohol copolymer, and starch. The above polyalcohols can be used alone or in combination of two or more.
The saponification degree of polyvinyl alcohol or ethylene-vinyl alcohol copolymer is preferably 95 mol% or more, and more preferably 98 mol% or more. The average degree of polymerization is preferably 50 to 2,000, and more preferably 200 to 1,000.

  The polycarboxylic acid and the polyalcohol in the gas barrier layer (II) are preferably contained so that the molar ratio of OH group to COOH group (OH group / COOH group) is 0.01-20. It is more preferable to contain so that it may become 01-10, It is more preferable to contain so that it may become 0.02-5, It is most preferable to contain so that it may become 0.04-2.

  In the present invention, the gas barrier layer (II) preferably contains polyacrylamide, polymethacrylamide or polyamine. By containing these compounds, the polycarboxylic acid in the gas barrier layer (II) reacts with these compounds in addition to reacting with the metal compound in the polyamide resin substrate (I). Can be improved.

The polyamine has two or more amino groups selected from primary and secondary as amino groups in the molecule. Specific examples thereof include polyallylamine, polyvinylamine, branched polyethyleneimine. And polysaccharides having an amino group in the side chain such as linear polyethyleneimine, polylysine and chitosan, and polyamides having an amino group in the side chain such as polyarginine.
The weight average molecular weight of the polyamine is preferably 5,000 to 150,000. If the weight average molecular weight of the polyamine is too low, the resulting gas barrier layer (II) becomes fragile. On the other hand, if the molecular weight is too high, handling properties are impaired, and in some cases, a gas barrier layer (II) described later is formed. Therefore, the gas barrier layer (II) obtained by agglomeration in the coating liquid may have a gas barrier property impaired.

  The mass ratio of polyamine to polycarboxylic acid (polyamine / polycarboxylic acid) in the gas barrier layer (II) is preferably 12.5 / 87.5 to 27.5 / 72.5. If the mass ratio of the polyamine is lower than this, the crosslinking of the carboxyl group of the polycarboxylic acid becomes insufficient. Conversely, if the mass ratio of the polyamine is higher than this, the crosslinking of the amino group of the polyamine becomes insufficient. However, the gas barrier laminate (III) obtained may be inferior in gas barrier properties.

The gas barrier layer (II) in the present invention may contain a crosslinking agent. By containing a cross-linking agent, gas barrier properties can be enhanced.
The content of the crosslinking agent in the gas barrier layer (II) is preferably 0.1 to 30 parts by mass and more preferably 1 to 20 parts by mass with respect to 100 parts by mass of the polycarboxylic acid.
Examples of the crosslinking agent include a compound having self-crosslinking property and a compound having a plurality of functional groups that react with a carboxyl group in the molecule. When the gas barrier layer (II) contains a polyalcohol, it reacts with a hydroxyl group. A compound having a plurality of functional groups in the molecule may also be used. Preferable examples of the crosslinking agent include isocyanate compounds, melamine compounds, urea compounds, epoxy compounds, carbodiimide compounds, zirconium salt compounds such as zirconium ammonium carbonate, metal alkoxides, and the like. These crosslinking agents may be used in combination.

  A metal alkoxide is a compound containing a metal to which an alkoxy group is bonded, and an alkyl group substituted with a functional group having reactivity with a halogen or a carboxyl group may be bonded instead of a part of the alkoxy group. . Here, the metal includes atoms such as Si, Al, Ti and Zr, the halogen includes chlorine, iodine, bromine and the like, and the functional group having reactivity with a carboxyl group is an epoxy group. , Amino groups, isocyanate groups, ureido groups and the like, and alkyl groups include methyl group, ethyl group, n-propyl group, iso-propyl group, n-butyl group, iso-butyl group and the like. Examples of such compounds include tetramethoxysilane, tetraethoxysilane, chlorotriethoxysilane, 3-glycidoxypropyltrimethoxysilane, 3-glycidoxypropyltriethoxysilane, 3-aminopropyltrimethoxysilane, Alkoxysilane compounds such as 3-aminopropyltriethoxysilane, 3-ureidopropyltriethoxysilane, 3-isocyanatopropyltriethoxysilane, alkoxytitanium compounds such as tetraisopropoxytitanium and tetraethoxytitanium, alkoxy such as triisopropoxyaluminum Examples thereof include aluminum compounds and alkoxyzirconium compounds such as tetraisopropoxyzirconium.

  These metal alkoxides must be partially or wholly hydrolyzed, partially hydrolyzed or condensed, fully hydrolyzed and partially condensed, or a combination of these. You can also.

  When the above metal alkoxide and polycarboxylic acid are mixed, it may be difficult for both to react and to be applied. Therefore, it is preferable to form a hydrolysis condensate in advance before mixing. As a method for forming the hydrolysis-condensation product, a method used in a known sol-gel method can be applied.

In the gas barrier layer (II) in the present invention, as long as the gas barrier property and the adhesion to the polyamide resin substrate (I) are not significantly impaired, a thermal stabilizer, an antioxidant, a reinforcing material, a pigment, a deterioration preventing agent, A weathering agent, a flame retardant, a plasticizer, a release agent, a lubricant, an antiseptic, an antifoaming agent, a wetting agent, a viscosity modifier, and the like may be added.
Examples of heat stabilizers, antioxidants, and deterioration inhibitors include hindered phenols, phosphorus compounds, hindered amines, sulfur compounds, copper compounds, alkali metal halides, and the like. May be.
Examples of the reinforcing material include clay, talc, wollastonite, silica, alumina, calcium silicate, sodium aluminate, sodium aluminosilicate, magnesium silicate, glass balloon, carbon black, zeolite, montmorillonite, hydrotalcite, fluorine mica, Examples thereof include metal fibers, metal whiskers, ceramic whiskers, potassium titanate whiskers, boron nitride, graphite, glass fibers, carbon fibers, fullerenes (C60, C70, etc.), carbon nanotubes, and the like.

  In the present invention, the thickness of the gas barrier layer (II) laminated on the polyamide resin substrate (I) is preferably thicker than 0.05 μm in order to sufficiently enhance the gas barrier property of the gas barrier laminate (III), From the viewpoint of economy, it is preferable that the thickness is less than 5.0 μm.

The gas barrier layer (II) in the present invention can be formed by applying and drying a coating liquid for forming the gas barrier layer (II) on the polyamide resin substrate (I).
Since the coating liquid is preferably aqueous from the viewpoint of workability, the polycarboxylic acid, polyalcohol and polyamine constituting the coating liquid are preferably water-soluble or water-dispersible, and water-soluble. It is more preferable that

  In the present invention, when an aqueous coating solution is prepared by mixing a polycarboxylic acid and a polyalcohol, it is preferable to add 0.1 to 20 equivalent% of an alkali compound with respect to the carboxyl group of the polycarboxylic acid. . Since polycarboxylic acid has high hydrophilicity when the content of carboxyl group is large, it can be made into an aqueous solution without adding an alkali compound. However, by adding an appropriate amount of an alkali compound, the gas barrier property and dyeing resistance of the resulting gas barrier laminate (III) can be significantly improved. The alkali compound only needs to be capable of neutralizing the carboxyl group of the polycarboxylic acid, and the addition amount thereof is preferably 0.1 to 20 mol% with respect to the carboxyl group of the polycarboxylic acid.

  The coating liquid can be prepared by a known method using a melting pot equipped with a stirrer. For example, a polycarboxylic acid and a polyalcohol are separately made into aqueous solutions and mixed before coating. The method is preferred. At this time, if the alkali compound is added to the aqueous solution of the polycarboxylic acid, the stability of the aqueous solution can be improved.

  Moreover, in this invention, when mixing polycarboxylic acid and polyamine and preparing an aqueous coating liquid, in order to suppress gelatinization, it is preferable to add a base to polycarboxylic acid. The base is not particularly limited as long as it does not inhibit the gas barrier property of the resulting gas barrier laminate (III), and examples thereof include inorganic substances such as sodium hydroxide and calcium hydroxide, and organic substances such as ammonia, methylamine and diethanolamine. Ammonia is preferred because it is easily volatilized by drying and heat treatment. The addition amount of the base is preferably 0.6 equivalents or more, more preferably 0.7 equivalents or more, and more preferably 0.8 equivalents or more based on the carboxyl group of the polycarboxylic acid. preferable. If the amount of the base added is small, the coating solution may gel during coating, and it may be difficult to form the gas barrier layer (II) on the polyamide resin substrate (I).

  The method for applying the coating liquid for forming the gas barrier layer (II) to the polyamide resin substrate (I) is not particularly limited, and is an air knife coater, kiss roll coater, metering bar coater, gravure roll coater, reverse roll coater, dip. A coater, a die coater or the like, or a combination of these methods can be used.

After applying the coating liquid for forming the gas barrier layer (II) to the polyamide resin base material (I), the heat treatment may be performed immediately, and the formation of the dry film and the heat treatment may be performed at the same time. Heat treatment may be performed after moisture or the like is evaporated by hot air blowing or infrared irradiation to form a dry film. 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 (II) and physical properties such as gas barrier properties.
It does not specifically limit as a heat processing method, The method of heat-processing in dry atmosphere, such as oven, is mentioned. Considering shortening of the process, it is preferable to stretch the polyamide resin substrate (I) after applying the gas barrier layer (II) forming coating solution.
In any of the above cases, it is preferable that the polyamide resin base material (I) on which the gas barrier layer (II) is formed is subjected to a heat treatment for 5 minutes or less in a heated atmosphere of 100 ° C. or higher.

When the gas barrier layer (II) contains a polycarboxylic acid and a polyalcohol, it can be affected by their ratio, presence / absence of additive components, content thereof, and the like. The heat treatment temperature cannot be generally specified, but is preferably 100 to 300 ° C, more preferably 120 to 250 ° C, further preferably 140 to 240 ° C, and 160 to 220 ° C. It is particularly preferred. If the heat treatment temperature is too low, the cross-linking reaction between the polycarboxylic acid and the polyalcohol cannot sufficiently proceed, and it may be difficult to obtain a laminate having sufficient gas barrier properties, while it is too high. In addition, the gas barrier layer (II) may become brittle.
The heat treatment time is preferably 5 minutes or less, more preferably from 1 second to 5 minutes, further preferably from 3 seconds to 2 minutes, and particularly preferably from 5 seconds to 1 minute. . If the heat treatment time is too short, the crosslinking reaction cannot proceed sufficiently, and it becomes difficult to obtain a laminate having gas barrier properties and dyeing resistance. On the other hand, if the heat treatment time is too long, productivity decreases.

  The coating liquid for forming the gas barrier layer (II) applied to the polyamide resin substrate (I) is irradiated with high-energy rays such as ultraviolet rays, X-rays, and electron beams as necessary before and after the drying. May be applied. In such a case, a component that is crosslinked or polymerized by irradiation with high energy rays may be blended.

Since the gas barrier laminate (III) has the above-described configuration, it has excellent gas barrier properties. The gas barrier laminate (III) treated with hydrothermal treatment at 95 ° C. for 30 minutes has a temperature of 20 ° C. and a relative humidity of 65%. oxygen permeability was measured under an atmosphere ^{of, 300ml / (m 2 · day} · MPa) can be less, the oxygen permeability, it is ^{0.01~300ml / (m 2 · day ·} MPa) it is preferred, more preferably ^{0.01~200ml / (m 2 · day ·} MPa), more preferably a ^{0.01~100ml / (m 2 · day ·} MPa).

The gas barrier laminate (III) can be produced by the following method.
Polyamide resin substrate (I) consisting of a single layer film, for example, a resin mixed with a metal compound is heated and melted with an extruder and extruded into a film from a T-die, air knife casting method, electrostatic application casting The film is cooled and solidified on a cooling drum that is rotated by a known casting method such as a method to obtain an unstretched polyamide resin substrate (I) film.
The polyamide resin substrate (I) composed of a multilayer film is obtained by, for example, heating and melting a polyamide resin mixed with a metal compound or titanium oxide in the extruder A, and heating and melting the polyamide resin in the extruder B. 2 types of molten resins are superposed in a die, for example, a two-layer film of metal-containing layer (M) / polyamide resin layer (R) is extruded from a T-die and cooled and solidified in the same manner as above. Can be obtained in an unstretched state.
By including a metal compound in the polyamide resin substrate (I) by such a method, the step of laminating a layer containing a metal compound, which has been conventionally performed, on the substrate can be omitted.
The gas barrier layer (II) forming coating solution is applied to the obtained single-layer or multi-layer unstretched film by the above-described method to form the gas barrier layer (II), and the tenter-type simultaneous biaxial stretching machine is used. The gas barrier laminate (III) stretched simultaneously biaxially can be obtained by performing simultaneous biaxial stretching in the machine direction (MD) and the transverse direction (TD).
Further, after stretching the obtained unstretched film in the machine direction (MD), the gas barrier layer (II) forming coating solution is applied by the above-described method to form the gas barrier layer (II), and then the transverse direction (TD) ) Is stretched to obtain a gas barrier laminate (III) that is successively biaxially stretched.
If the unstretched film is oriented, the stretchability may be lowered in a later step. Therefore, it is preferable that the unstretched film is substantially amorphous and non-oriented.

In this invention, it is preferable to transfer an unstretched film to the water tank temperature-controlled so that it may not exceed 80 degreeC, to perform a water immersion process within 5 minutes, and to perform a 0.5-15% moisture absorption process.
In addition, the stretching ratio of the film is preferably 1.5 times or more in the case of uniaxial stretching, and also in the case of longitudinal and lateral biaxial stretching, it is preferably 1.5 times or more in the vertical and horizontal directions. Usually, it is preferably 3 times or more, more preferably 6 to 20 times, and even more preferably 6.5 to 13 times. When the draw ratio is within this range, it becomes possible to obtain a gas barrier laminate (III) having excellent mechanical properties.
The film that has undergone the stretching process is heat-set at a temperature of 150 to 300 ° C. in the tenter where the stretching process has been performed, and in the range of 0 to 10%, preferably 2 to 6% as necessary, in the machine direction and A lateral relaxation treatment is performed. In order to reduce the heat shrinkage rate, it is desirable not only to optimize the temperature and time of the heat setting time, but also to perform the heat relaxation process at a temperature lower than the maximum temperature of the heat setting process.

  The stretching method is not particularly limited, but it is preferable to use a simultaneous biaxial stretching method. The simultaneous biaxial stretching method can generally have practical characteristics such as mechanical characteristics, optical characteristics, thermal dimensional stability, and pinhole resistance. In addition, in the sequential biaxial stretching method in which the transverse stretching is performed after the longitudinal stretching, the orientation crystallization of the film proceeds during the longitudinal stretching, and the stretchability of the thermoplastic resin during the transverse stretching is reduced, thereby blending the metal compound. When the amount is large, the breaking frequency of the film tends to increase. For this reason, in this invention, it is preferable to perform a water absorption process and to take the simultaneous biaxial stretching method.

  The gas barrier laminate (III) can be treated in a humidified atmosphere after producing the laminate for the purpose of enhancing gas barrier properties. By the humidification treatment, the action of the metal compound of the polyamide resin substrate (I) and the polycarboxylic acid of the gas barrier layer (II) can be further promoted. In such humidification treatment, the laminate may be left in an atmosphere of high temperature and high humidity, or the laminate may be directly contacted with high temperature water. Humidification conditions vary depending on various purposes, 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. 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 layer (II) surface of the gas barrier laminate (III) and the opposite surface may be subjected to surface treatment such as corona discharge treatment, if necessary.

  The laminate of the present invention has a configuration in which a heat seal resin layer is disposed directly or via an adhesive on the gas barrier layer (II) side of the gas barrier laminate (III). By adopting such a configuration, it has excellent gas barrier properties and dyeing resistance, and when used as a packaging bag or container, dyeing of the polyamide resin substrate (I) by the contents can be suppressed.

  As a configuration of the laminate of the present invention, a configuration in which a heat sealing resin layer is laminated directly or via an adhesive layer on the gas barrier layer (II) of the gas barrier laminate (III) can be mentioned as a basic configuration. One layer of another gas barrier layer (II), gas barrier laminate (III), another polyamide resin layer, or another thermoplastic resin layer on the opposite side of the gas barrier layer (II) of the conductive laminate (III) Two or more layers may be laminated.

  As other thermoplastic resin layers, polyolefin resins such as polyethylene, polypropylene, ionomer, polyethylene terephthalate, polyethylene isophthalate, polyethylene naphthalate, polytrimethylene terephthalate, polytrimethylene naphthalate, polybutylene terephthalate, polybutylene naphthalate, Examples thereof include polyester resins such as polylactic acid, vinyl chloride, polystyrene resins, polycarbonate resins, polyarylate resins, ethylene-vinyl acetate copolymers, ethylene-vinyl alcohol copolymers, and mixtures thereof. The polyamide resin layer and the thermoplastic resin layer may be a film or a resin layer.

  You may laminate | stack an inorganic oxide vapor deposition layer or an inorganic oxide vapor deposition film other than a thermoplastic resin layer.

The resin used as the heat-sealable resin layer includes low density polyethylene, medium density polyethylene, high density polyethylene, linear polyethylene, polypropylene, ethylene-vinyl acetate copolymer, ionomer resin, ethylene-acrylic acid / methacrylic acid copolymer For example, polyethylene-polypropylene, polyethylene / polypropylene copolymer, which has high heat seal strength and high material strength, such as ethylene-acrylic acid / methacrylic acid ester copolymer, acid-modified polyethylene / polypropylene resin, and polyvinyl acetate resin. Polyolefin resins such as polymers are preferred. These resins may be used alone, may be used by copolymerization or melt-mixing with other resins and components, or may be used after modification.
The heat seal resin layer may be a sealant film or sheet made of the heat seal resin or a resin layer. The sealant film or sheet may be in an unstretched state or in a stretched state at a low magnification, but practically it is preferably in an unstretched state.
The thickness of the heat sealing resin layer is not particularly limited, but is preferably 20 to 300 μm, and more preferably 30 to 200 μm.

  In the present invention, as a method of laminating each layer, when laminating a film, an inorganic oxide vapor-deposited film, or the like, a lamination method using a known adhesive such as a dry lamination method or a solventless lamination method can be mentioned.

  Adhesives include two-part curable polyurethane adhesives, polyvinyl acetate adhesives, homopolymers such as ethyl, butyl, 2-ethylhexyl ester of acrylic acid and methyl methacrylate, acrylonitrile, styrene, etc. Copolymers composed of polyacrylic acid ester adhesives, cyanoacrylate adhesives, copolymers of ethylene and monomers such as vinyl acetate, ethyl acrylate, acrylic acid, methacrylic acid, etc. Adhesives, cellulose adhesives, polyester adhesives, polyamide adhesives, polyimide adhesives, amino resin adhesives made of urea resin or melamine resin, phenolic resin adhesives, epoxy adhesives, reactive type (Meth) acrylic acid adhesive, chloroprene rubber, nitrile rubber , Styrene - inorganic adhesive made of butadiene rubber, a silicone-based adhesive, an alkali metal silicate, inorganic adhesive made of low-melting-point glass, and other adhesives. These adhesives may be any of an aqueous type, a solution type, an emulsion type, a dispersion type, and the reaction mechanism may be any of a chemical reaction type, a solvent volatilization type, a heat welding type, a hot pressure type, and the like.

The adhesive can be applied by roll coating, gravure coating, kiss coating or other coating methods or printing methods. Although there is no limitation in particular in the adhesive application quantity, it is 0.1-10 g / m < ² > (dry state) generally.

Examples of the method for laminating the heat sealing resin layer include a method of extrusion lamination directly or via an anchor coat layer.
For the extrusion lamination method, one or more resin layers that can be melt-extruded are extruded and the resin layers are laminated, or the resin layer that can be melt-extruded as an adhesive is extruded as an adhesive layer, and a sealant film is laminated. There are ways to do this. The thickness of the extruded resin layer as the adhesive layer is generally 10 to 50 μm.

As the anchor coating agent, commercially available anchor coating agents such as isocyanate, polyethyleneimine, polybutadiene, and organic titanium can be used. The anchor coating agent can be applied by roll coating, gravure coating, kiss coating or other coating methods or printing methods. Although it does not specifically limit as an application quantity of an anchor coating agent, Generally, it is 0.01-1 g / m < ² > (dry state).

  Examples of the method for laminating the heat sealing resin layer include a method of extrusion lamination directly or via an anchor coat layer. In the extrusion lamination method, one or more meltable resin layers are extruded and the resin layers are laminated, or the resin layer that can be melt-extruded as an adhesive is extruded as an adhesive layer, and a sealant film is laminated. There are methods. The thickness of the extruded resin layer as the total adhesion is not particularly limited, but is generally 10 to 50 μm.

  The laminate of the present invention can be suitably used as a packaging material that requires gas barrier properties and dye resistance while taking advantage of the excellent properties of the polyamide resin substrate. For example, the heat-sealing resin layer can be heat-sealed to form a bag-like body or used as a packaging body such as a lid material for trays or cup packaging. Examples of the form of the bag include a three-side seal bag, a four-side seal bag, a pillow bag, and a standing pouch. In this packaging bag, for example, food and drink, fruit, juice, drinking water, liquor, cooked food, marine products, frozen food, meat products, boiled food, rice cake, liquid soup, seasoning, etc. Contents such as various foods and drinks, liquid detergents, cosmetics, and chemical products can be filled and packaged.

  A dyeable substance, regardless of whether it is a synthetic or natural product, generally refers to a pigment that is added to food or contained in itself, including carotenoids, flavonoids, porphyrins, etc. Examples thereof include lycopene (lycopene) contained in tomato, curcumin contained in curry, melanoidin contained in soy sauce, and caramel pigment.

  EXAMPLES Next, although an Example demonstrates this invention concretely, this invention is not limited to these Examples.

1. Measuring method

(1) Thickness of each layer The obtained gas barrier laminate (III) is allowed to stand in an environment of 23 ° C. and 50% RH for 2 hours or more, and then a film cross-section is observed with a scanning electron microscope (SEM). The thickness was measured.

(2) Oxygen permeability After the obtained gas barrier laminate (III) was hydrothermally treated at 95 ° C. for 30 minutes, it was left in an environment of 23 ° C. and 50% RH for 2 hours or more. Using an oxygen barrier measuring instrument (OX-TRAN 2/20) manufactured by a company, oxygen permeability was measured in an atmosphere at a temperature of 20 ° C. and a relative humidity of 65%. The unit is ml / (m ² · day · MPa).

(3) Dye resistance The corona discharge treatment was performed on the gas barrier layer (II) surface and the opposite surface of the obtained gas barrier laminate (III) to form a polyurethane adhesive (Dick Dry LX-500 manufactured by DIC Graphics). / KR-90S two-pack type), polyester film (Embret PET-12 manufactured by Unitika Co., Ltd.) / Adhesive layer / gas barrier laminate (III) / adhesive layer / unstretched polypropylene film (Mitsui Chemicals Tosero) A laminate having a configuration of RXC-22 50 μm) was produced. At this time, the gas barrier layer (II) of the gas barrier laminate (III) was disposed on the unstretched polypropylene film side.
First, an adhesive is applied to the corona-treated surface of the polyester film, and a nip roll is formed between the adhesive-coated surface and the opposite surface of the gas barrier layer (II) of the gas-barrier laminate (III) subjected to corona discharge treatment. Adhesive is applied to the gas barrier layer (II) of the gas barrier laminate (III) of the laminated film under the nip condition (50 ° C.), and the adhesive-coated surface and the corona-treated surface of the unstretched polypropylene film are nip-rolled. (Nip condition 50 degreeC) It bonded together. The adhesive was applied so that the amount applied was 3 g / m ² , dried at 80 ° C. for 10 seconds, and then bonded. The laminated film was aged at 40 ° C. for 5 days to obtain a laminate.
The obtained laminate was cut into a size of 200 mm in length and 300 mm in width, and an impulse sealer was used to create a three-sided bag with an outer dimension of 200 mm in length and 150 mm in width and a seal width of 10 mm, and the contents were (A) retort curry Or (B) 200 g of tomato boiled and sealed, sealed, and using a high-temperature high-pressure cooking sterilizer (RCS-60SPXTG manufactured by Nisaka Manufacturing Co., Ltd.), at a temperature of 135 ° C. and a pressure of 2.8 kgf / cm ² , Retort treatment was performed for 30 minutes in a hot water shower type.
After the treatment, the contents were removed from the bag, the polypropylene film was peeled off with water to expose the polyamide resin substrate (I), and the degree of dyeing was visually confirmed. If the polyamide resin base material (I) was not dyed, it was marked as ◯, and if it was dyed, it was marked as x.

2. Raw materials The raw materials used in the following examples and comparative examples are as follows.
(1) Polyamide resin base material (I) Polyamide resin for constitution PA6: Nylon 6 resin (Unitika A1030BRF, relative viscosity 3.0)

(2) Polyamide resin base material (I) Metal compound / magnesium oxide for construction (Puremag FNM-G average particle size 0.4 μm, manufactured by Tateho Chemical Co., Ltd.)
・ Magnesium carbonate (MSJ average particle size 1.2μm, manufactured by Kamishima Chemical Co., Ltd.)
・ Calcium carbonate (Vigot 15 average particle size 0.5 μm, manufactured by Shiroishi Kogyo Co., Ltd.)
・ Zinc oxide (FINEX-50 average particle size 0.02 μm, manufactured by Sakai Chemical Industry Co., Ltd.)
・ Titanium oxide (KRONOS manufactured by Titanium Industry Co., Ltd., rutile type, average particle size 0.4 μm)

(3) Polyamide resin substrate (I) Metal compound master chip for constitution Each PA6 and metal compound were kneaded so as to have the following mass ratio.
・ Master chip 1
PA6 / magnesium oxide = 55/45.
It was used when preparing the metal-containing layer (M) having a metal compound content of 15 to 45% by mass.
・ Master chip 2
PA6 / magnesium oxide = 25/75.
It was used when preparing the metal-containing layer (M) in which the content of the metal compound exceeded 45% by mass.
・ Master chip 3
PA6 / magnesium oxide = 85/15.
It was used when preparing a metal-containing layer (M) having a metal compound content of less than 15% by mass.
・ Master chip 4
PA6 / magnesium carbonate = 85/15.
・ Master chip 5
PA6 / calcium carbonate = 85/15.
・ Master chip 6
PA6 / zinc oxide = 85/15.
・ Master chip 7
PA6 / titanium oxide = 85/15.

(4) Polycarboxylic acid component / EMA aqueous solution of gas barrier layer (II) forming coating solution:
EMA (weight average molecular weight 60,000) and sodium hydroxide were added to water, dissolved by heating, and cooled to room temperature. 10 mol% of EMA carboxyl groups were neutralized with sodium hydroxide, solids EMA aqueous solution of 15% by mass.
-PAA aqueous solution:
10 mol% of the carboxyl group of polyacrylic acid prepared by using polyacrylic acid (A10H manufactured by Toagosei Co., Ltd., number average molecular weight 200,000, 25% by weight aqueous solution) and sodium hydroxide is contained in sodium hydroxide. An aqueous polyacrylic acid (PAA) solution having a solid content of 15% by mass.

(5) Other resin component and PVA aqueous solution of gas barrier layer (II) forming coating solution:
Polyvinyl alcohol (Polyal 105 manufactured by Kuraray Co., Ltd., saponification degree 98 to 99%, average polymerization degree about 500) was added to water, dissolved by heating, and then cooled to room temperature. PVA) aqueous solution.
・ PAM:
Polyacrylamide (manufactured by Kishida Chemical Co., Ltd., reagent, weight average molecular weight 9 million to 10 million, degree of polymerization 1270 to 141,000).

Example 1
Nylon 6 resin and master chip were mixed so that the content of magnesium oxide was 0.1% by mass. This mixture was charged into an extruder and melted in a 270 ° C. cylinder. The melt was extruded into a sheet form from a T-die orifice, brought into close contact with a rotating drum cooled to 10 ° C., and quenched to obtain an unstretched polyamide resin substrate (I) film having a thickness of 150 μm. The obtained unstretched film was sent to a 50 ° C. hot water tank and subjected to a water immersion treatment for 2 minutes.
Next, an EMA aqueous solution and a PVA aqueous solution are mixed so that the mass ratio (solid content) of PVA and EMA is 50/50, and a coating liquid for forming a gas barrier layer (II) having a solid content of 10% by mass. Got. This coating solution was applied to one side of an unstretched film that had been subjected to water immersion treatment, and then dried.
The end of the film was held by a clip of a tenter simultaneous biaxial stretching machine, and stretched at 180 ° C. to MD and TD by 3.3 times. Thereafter, a relaxation rate of TD was set to 5%, heat treatment was performed at 210 ° C. for 4 seconds, and the mixture was slowly cooled to room temperature. A polyamide resin substrate (I) having a thickness of 15 μm was coated with a gas barrier layer (0.3 μm in thickness) A gas barrier laminate (III) obtained by laminating II) was obtained.

Examples 2-9, Comparative Examples 1-3
Example 1 except that the nylon 6 resin and the master chip were mixed so that the metal compound content shown in Table 1 was obtained, and the thickness after stretching was adjusted to the thickness shown in Table 1. Similarly, an unstretched polyamide resin base material (I) film was obtained and subjected to water immersion treatment.
Next, with respect to other resins such as PVA and polycarboxylic acids, the gas barrier layer (II) was the same as in Example 1 except that the types and mass ratios (solid content) were as shown in Table 1. ) A forming coating solution was prepared.
Using the obtained coating solution, it was applied to an unstretched film, dried and then simultaneously biaxially stretched in the same manner as in Example 1, except that the thickness after stretching was as shown in Table 1. Thus, a gas barrier laminate (III) was obtained.

Example 10
Nylon 6 resin, master chip 1 and master chip 7 were mixed in the same manner as in Example 1 except that the magnesium oxide content was 15 mass% and titanium oxide was 10 mass%. III) was obtained.

Example 11
A coating solution for forming the gas barrier layer (II) was prepared as follows.
That is, polyacrylic acid (PAA) having a number average molecular weight of 200,000 was dissolved in distilled water to obtain a PAA aqueous solution having a solid content concentration of 13% by mass in the aqueous solution. Subsequently, a 13% by mass aqueous ammonia solution was added to the aqueous PAA solution to neutralize 1 mol% of the carboxyl groups of the PAA, thereby obtaining a partially neutralized aqueous solution of PAA.
Further, 100 parts by mass of polyacrylic acid (PAA) having a number average molecular weight of 40,000 was dissolved in 1064 parts by mass of methanol, and then 166 parts by mass of γ-aminopropyltrimethoxysilane (APTMOS) was added with stirring. Thus, an APTMOS methanol solution (11-1) was obtained. In the APTMOS methanol solution (11-1), at least a part of the amino group of APTMOS is neutralized by the carboxyl group of PAA.
Next, a TMOS methanol solution was prepared by dissolving 34.5 parts by mass of tetramethoxysilane (TMOS) in 34.5 parts by mass of methanol. While maintaining the temperature of this TMOS methanol solution at 10 ° C. or lower, 2.3 parts by weight of distilled water and 5.7 parts by weight of 0.1M hydrochloric acid were added, and hydrolysis and condensation were carried out at 10 ° C. for 60 minutes with stirring. By performing the reaction, a solution (11-2) was obtained.
Subsequently, after the solution (11-2) was diluted with 214.7 parts by mass of methanol and 436.1 parts by mass of distilled water, 235.9 parts by mass of the partially neutralized aqueous solution of PAA was added while stirring. A solution (11-3) was obtained.
Subsequently, 36.2 parts by mass of the APTMOS methanol solution (11-1) was added while stirring the solution (11-3), and the mixture was further stirred for 30 minutes to obtain a solution (11-4).
A gas barrier laminate (III) was obtained in the same manner as in Example 8, except that the solution (11-4) prepared by the above method was used as the gas barrier layer (II) forming coating solution.

Example 12
Nylon 6 resin and master chip were mixed so that the content of magnesium oxide was 50 parts by mass. This mixture was put into an extruder A and melt-extruded at 260 ° C. On the other hand, nylon 6 resin was charged into Extruder B and melt extruded at 260 ° C.
The two types of resins melted in the extruder A and the extruder B are superposed in a die, and a sheet having a two-layer structure of metal-containing layer (M) / polyamide resin layer (R) is extruded from the T die, and the surface temperature The film was brought into close contact with a 20 ° C. cooling roll to obtain an unstretched multilayer film having a thickness of 150 μm with (M) / (R) = 5/145 μm. The obtained unstretched multilayer film was sent to a 50 ° C. hot water tank and subjected to water immersion treatment for 2 minutes.
Next, the coating liquid prepared in the same manner as in Example 1 was applied to the metal-containing layer (M) surface of the unstretched multilayer film and then dried.
In the same manner as in Example 1, it was subjected to simultaneous biaxial stretching and heat treatment, and consisted of a metal-containing layer (M) having a thickness of 0.5 μm and a polyamide resin layer (R) having a thickness of 14.5 μm, and having a thickness of 15 μm. A gas barrier laminate (III) in which a gas barrier layer (II) having a thickness of 0.3 μm was laminated on the metal-containing layer (M) of the polyamide resin substrate (I) was obtained.

Examples 13-14, 16
Nylon 6 resin and master chip are mixed so that the composition described in Table 1 is obtained, and the extrusion amounts of extruders A and B are changed so that the thickness after stretching becomes the thickness described in Table 1. Except that, an unstretched multilayer film was obtained in the same manner as in Example 11 and subjected to water immersion treatment.

Example 15
A metal-containing layer (M) having a thickness of 3 μm and a thickness were obtained in the same manner as in Example 12 except that the coating liquid for forming the gas barrier layer (II) was applied to the resin layer (R) surface of the unstretched multilayer film. A gas barrier laminate (III) is obtained by laminating a gas barrier layer (II) having a thickness of 0.3 μm on a resin layer (R) having a thickness of 15 μm and a polyamide resin layer having a thickness of 12 μm. It was.

Example 17
Nylon 6 resin, master chip 2 and master chip 7 were mixed in the same manner as in Example 12 except that the magnesium oxide content was 50 mass% and titanium oxide was 10 mass%. A gas barrier layer having a thickness of 0.3 μm is added to a metal-containing layer (M) of a polyamide resin layer having a thickness of 15 μm, which is composed of a metal-containing layer having a thickness of 5 μm and a polyamide resin layer having a thickness of 14.5 μm. A gas barrier laminate (III) obtained by laminating II) was obtained.

Example 18
A metal-containing layer (M) having a thickness of 0.5 μm and a thickness of 14.5 μm are the same as in Example 12 except that the master chip 7 is mixed with nylon 6 resin so that the titanium oxide is 10% by mass. A gas barrier laminate comprising a metal resin layer (M) of a polyamide resin layer having a thickness of 15 μm and a gas barrier layer (II) having a thickness of 0.3 μm, comprising a polyamide resin layer (R) containing titanium oxide of III) was obtained.

  Table 1 shows the structures of the gas barrier laminates (III) obtained in Examples and Comparative Examples and the results of measuring oxygen permeability.

In each of Examples 1 to 18, a gas barrier laminate (III) excellent in gas barrier properties was obtained.
In Comparative Example 1, since the metal compound contained in the polyamide resin substrate (I) was less than 0.1% by mass, a gas barrier laminate (III) having sufficient gas barrier properties and dyeing resistance could not be obtained. .
In Comparative Example 2, since the metal compound contained in the polyamide resin substrate (I) exceeded 70% by mass, it was broken during stretching during film formation, and the gas barrier laminate (III) was not obtained.
In Comparative Example 3, since the gas barrier layer (II) did not contain a polycarboxylic acid, a gas barrier laminate (III) having sufficient gas barrier properties and dyeing resistance could not be obtained.

Claims (9)

  The gas barrier layer (II) side of the gas barrier laminate (III) obtained by laminating the gas barrier layer (II) containing polycarboxylic acid on the polyamide resin substrate (I) containing 0.1 to 70% by mass of the metal compound And a heat sealing resin layer laminated directly or via an adhesive layer.   The laminate according to claim 1, wherein the polyamide resin substrate (I) is a multilayer film, and at least one layer thereof contains 0.1 to 70% by mass of a metal compound.   The laminate according to claim 1, wherein the gas barrier layer (II) contains a polyalcohol.   The laminated body according to any one of claims 1 to 3, wherein the metal constituting the metal compound contained in the polyamide resin substrate (I) is one selected from magnesium, calcium, and zinc. The gas barrier laminate (III), after hydrothermal treatment at 95 ° C. for 30 minutes, has an oxygen permeability of 300 ml / (m ² · day · MPa) or less in an atmosphere at 20 ° C. and a relative humidity of 65%. The laminate according to any one of claims 1 to 4, which is characterized.   The laminate according to any one of claims 1 to 5, wherein the gas barrier laminate (III) is simultaneously or sequentially biaxially stretched.   The laminate according to any one of claims 1 to 6, wherein the polyamide resin substrate (I) contains a pigment.   The laminate according to any one of claims 1 to 7, wherein the pigment contained in the polyamide resin substrate (I) is a white pigment. A packaging bag or container, wherein the laminate according to any one of claims 1 to 8 is used, and a heat sealing resin layer is disposed on the content side.