JP2015150843A - gas barrier laminate - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a gas barrier laminate that is excellent in productivity and economical efficiency and has excellent gas barrier property even under a high humidity condition.SOLUTION: The gas barrier laminate comprises a gas barrier layer II laminated on a plastic substrate I. The plastic substrate I contains a monovalent metal compound by 0.1 to 70 mass%; and the gas barrier layer II contains a polycarboxylic acid. The plastic substrate I is a multilayer film, in which at least one layer contains a monovalent metal compound and a compound of a metal having a valence of 2 or more, by 0.1 to 70 mass% in total of the monovalent metal compound and the compound of a metal having a valence of 2 or more. The plastic substrate I comprises a polyamide resin or a polyester resin; and the gas barrier layer II contains a polyalcohol.

Description

  The present invention relates to a gas barrier laminate having excellent gas barrier properties even under high humidity.

  Plastic films such as polyamide films are excellent in strength, transparency and moldability, and are therefore used in a wide range of applications as packaging materials. However, since these plastic films have a large gas permeability such as oxygen, when used for packaging general foods, retort-treated foods, cosmetics, medical supplies, agricultural chemicals, etc., oxygen that has permeated the film while stored for a long period of time. The contents may be altered by such gases. Therefore, the plastic film used for these packaging applications is required to have a gas barrier property, and in the packaging of foods containing moisture, the gas barrier property under high humidity is also required.

  As a method for imparting a gas barrier property to a plastic substrate, for example, in Patent Document 1, a gas barrier laminate obtained by laminating a plastic substrate, a gas barrier layer, and a polymer layer containing a divalent or higher metal compound, A method for heat treatment in the presence of water is described.

  However, in the method of Patent Document 1, after forming a gas barrier layer, pressure treatment using an autoclave is performed in water containing a metal compound, and it is difficult to carry out continuously, resulting in poor productivity. It was a thing. In Patent Document 1, a solvent-based paint is applied on a plastic substrate and dried to form an undercoat layer, and then a water-based paint is applied and dried to form a gas barrier layer. Therefore, the method of Patent Document 1 has a problem from the viewpoint of economy and productivity, for example, an explosion-proof facility is required to use a solvent-based paint, and a plurality of coatings are required.

  The present inventor examined the simultaneous application of the solvent-based undercoat layer-forming paint and the water-based gas barrier layer-forming paint using a curtain coater or the like in the method of Patent Document 1, but at the time of drying. The coating became uneven, and the resulting laminate did not exhibit gas barrier properties. Also, instead of using a water-based paint for forming the undercoat layer, it can be applied simultaneously using a curtain coater or the like, or after applying and drying the water-based paint for forming the undercoat layer, the water-based paint for forming the gas barrier layer However, none of the obtained laminates exhibited gas barrier properties.

JP 2004-322626 A

  An object of the present invention is to provide a gas barrier laminate that solves the above problems, has excellent productivity and economy, and has excellent gas barrier properties even under high humidity.

As a result of intensive studies on the above problems, the present inventor uses a plastic base material (I) containing a specific amount of a specific metal compound, and a gas barrier layer (II) containing a polycarboxylic acid on the plastic base material (I). The present inventors have found that the body has excellent gas barrier properties even under high humidity, and have reached the present invention.
That is, the gist of the present invention is as follows.
(1) A gas barrier laminate in which a gas barrier layer (II) is laminated on a plastic substrate (I), wherein the plastic substrate (I) contains 0.1 to 70% by mass of a monovalent metal compound And the gas barrier layer (II) contains a polycarboxylic acid.
(2) The gas barrier property according to (1), wherein the plastic substrate (I) is a multilayer film, and at least one layer thereof contains 0.1 to 70% by mass of a monovalent metal compound. Laminated body.
(3) The plastic substrate (I) further contains a divalent or higher valent metal compound, and contains a monovalent metal compound and a divalent or higher metal compound in an amount of 0.1 to 70% by mass. The gas barrier laminate according to (1) or (2), wherein
(4) The gas barrier laminate according to any one of (1) to (3), wherein the thermoplastic resin constituting the plastic substrate (I) is a polyamide resin or a polyester resin.
(5) The gas barrier layered product according to any one of (1) to (4), wherein the gas barrier layer (II) contains a polyalcohol.
(6) The gas barrier laminate according to any one of (1) to (5), wherein the metal constituting the monovalent metal compound is lithium or sodium.
(7) The gas barrier laminate according to any one of (3) to (6), wherein the metal constituting the divalent or higher metal compound is magnesium, calcium, or zinc.
(8) The oxygen permeability in an atmosphere of 20 ° C. and a relative humidity of 65% after hot water treatment at 95 ° C. for 30 minutes is 200 mL / (m ² · day · MPa) or less. The gas barrier laminate according to any one of 1 to 7.
(9) The gas barrier laminate according to any one of (1) to (8), which is simultaneously or sequentially biaxially stretched.
(10) A packaging bag comprising the gas barrier laminate according to any one of (1) to (9).

ADVANTAGE OF THE INVENTION According to this invention, it is excellent in productivity and economical efficiency, and can provide the gas-barrier laminated body which has the gas barrier property outstanding also under high humidity.
That is, in the present invention, the plastic base material containing a metal compound can be produced simply by adding the metal compound to the raw material of the plastic base material, and a conventional layer containing the metal compound is used as the base material. The step of stacking can be omitted. Therefore, a gas barrier laminate can be obtained with a smaller number of processes than before, and therefore, industrial merit is extremely large from the viewpoint of productivity and cost. In addition, the obtained gas barrier laminate has excellent gas barrier properties even under high humidity.

Hereinafter, the present invention will be described in detail.
The gas barrier laminate of the present invention is obtained by laminating a gas barrier layer (II) on a plastic substrate (I).

  The plastic substrate (I) needs to contain a monovalent metal compound (hereinafter sometimes abbreviated as “monovalent metal compound”). It is preferable to contain a metal compound having a valence higher than that (hereinafter sometimes abbreviated as “polyvalent metal compound”).

  Examples of the metal constituting the monovalent metal compound include lithium, sodium, potassium, rubidium, cesium and the like. Among them, lithium and sodium are preferable, and lithium is more preferable.

  Examples of the metal constituting the polyvalent metal compound used in combination with the monovalent metal compound include divalent metals such as magnesium, calcium, zinc, copper, cobalt and nickel, and trivalent or more metals such as aluminum, chromium and iron. Can be mentioned. From the viewpoint of gas barrier properties, magnesium, calcium and zinc are preferable, and magnesium is more preferable.

  Metal compounds include oxides, hydroxides, halides, inorganic salts such as carbonates, bicarbonates, phosphates, sulfates, acetates, formates, stearates, citrates, apples Examples thereof include carboxylic acid salts such as acid salts and maleic acid salts, and organic acid salts such as sulfonic acid salts, and oxides and carbonates are preferable. Moreover, you may use a metal simple substance as a metal compound.

  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 The thickness is more preferably 0.01 to 2.0 μm, and particularly preferably 0.05 to 1.0 μm. Since the haze of the plastic substrate (I) can be reduced, the metal compound preferably has a smaller average particle size. 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 plastic 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. .

  In the plastic substrate (I), the content of the monovalent metal compound needs 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, the content is preferably less than 5% by mass. When the content of the monovalent metal compound in the plastic substrate (I) is 0.1 to 70% by mass, the resulting gas barrier laminate can obtain excellent gas barrier properties. However, when the content of the metal compound in the plastic substrate (I) is less than 0.1% by mass, the crosslinked structure formed by reacting with the polycarboxylic acid in the gas barrier layer (II) is reduced and obtained. The gas barrier property of the gas barrier laminate decreases. On the other hand, the plastic substrate (I) having a content exceeding 70% by mass has a high frequency of breakage during stretching during film formation, tends to reduce productivity, and mechanical properties.

  Furthermore, when a polyvalent metal compound is contained, the monovalent metal compound and the polyvalent metal compound are preferably combined in an amount of 0.1 to 70% by mass. When a monovalent metal compound and a polyvalent metal compound are used in combination, the mass ratio of (monovalent metal compound / polyvalent metal compound) is 10/90 to 90/10 from the viewpoint of promoting the formation of a crosslinked structure. Is preferable, and it is more preferable that it is 10 / 90-60 / 40.

  The method for incorporating the metal compound into the plastic substrate (I) is not particularly limited, and it 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 plastic substrate (I), a method of kneading a thermoplastic resin and a metal compound with an extruder, a high concentration of the metal compound Examples thereof include a method (master batch method) in which a master batch mixed by kneading is prepared, and this is added to a thermoplastic resin and diluted. In the present invention, the master batch method is preferably employed.

  In the present invention, the thermoplastic resin constituting the plastic substrate (I) includes polyolefin resins such as polyethylene, polypropylene, and ionomer, polyamide resins such as polyamide 6, polyamide 66, polyamide 46, polyamide MXD6, and polyamide 9T, and polyethylene terephthalate. Polyester resins such as polyethylene isophthalate, polyethylene naphthalate, polytrimethylene terephthalate, polytrimethylene naphthalate, polybutylene terephthalate, polybutylene naphthalate, polylactic acid, vinyl chloride, polystyrene resin, polycarbonate resin, polyarylate resin, ethylene -Vinyl acetate copolymers, ethylene-vinyl alcohol copolymers or mixtures thereof. Among these thermoplastic resins, when a packaging bag is configured, polyamide resin is preferable because of excellent puncture strength and impact resistance, and polyester resin is preferable because of excellent heat resistance and economy. preferable.

  In the thermoplastic resin, if necessary, in a range that does not adversely affect the performance of the plastic substrate (I), a thermal 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 plastic substrate (I), and among them, silica may be added. preferable.

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

  As long as the plastic substrate (I) contains a metal compound and a thermoplastic resin, it may be a single-layer film or a multi-layer film. When the plastic 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 a metal compound or a single layer film in the multilayer film is referred to as “metal-containing layer (M)”, and layers other than the “metal-containing layer (M)” in the multilayer film are referred to as “resin layer ( R) ".

  When the plastic substrate (I) is a multilayer film, the gas barrier laminate is obtained by contacting the gas barrier layer (II) with the metal-containing layer (M) of the plastic substrate (I). , (R) / (M) / (II), (M) / (R) / (M) / (II), (II) / (M) / (R) / (M) / (II) Etc. 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 resin layer (R) of the plastic substrate (I) are in contact with each other, (M) / (R) / (II) and (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 resin layer (R) constituting the multilayer film is not particularly limited, and the total thickness (Mt) of the metal-containing layer (M) and the total of the resin layer (R). The ratio of 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. More preferably, it is more preferably 1/10 to 10/1.

  The above-mentioned additives may be added to the thermoplastic resin constituting the resin layer (R), and the resin layer (R) which is the outermost layer of the gas barrier laminate is made of silica for the purpose of improving the slip property. Etc. are preferably added.

  The gas barrier layer (II) constituting the gas barrier laminate of the present invention needs to contain a polycarboxylic acid. The polycarboxylic acid in the gas barrier layer (II) can exhibit gas barrier properties by reacting with the metal compound in the plastic 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 carboxyl groups in the side chains such as alginic acid, polyamides containing carboxyl groups, and polyesters. The said polycarboxylic acid may be used independently and may be used together.

  When the polycarboxylic acid is a polymer, the weight average molecular weight is preferably 1000 to 1000000, more preferably 10000 to 150,000, and further preferably 15000 to 110000. 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 copolymers, particularly ethylene-maleic acid copolymers (hereinafter sometimes abbreviated as “EMA”) have gas barrier properties. From the viewpoint, it is 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. . Moreover, it is preferable that the weight average molecular weights of EMA are 1000-1 million, It is more preferable that it is 3000-500000, It is further more preferable that it is 7000-300000, It is especially preferable that it is 10000-200000.

  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 plastic substrate (I), thereby improving the gas barrier property. be able to. Polyalcohol is a compound having two or more hydroxyl groups in the molecule. Examples of low molecular weight compounds include sugar alcohols such as glycerin and pentaerythritol, monosaccharides such as glucose, disaccharides such as maltose, and oligosaccharides such as galactooligosaccharide. Examples of the polymer compound include polysaccharides such as polyvinyl alcohol, ethylene-vinyl alcohol copolymer, and starch. The said polyalcohol may be used independently and may be used together. The saponification degree of polyvinyl alcohol or ethylene-vinyl alcohol copolymer is preferably 95 mol% or more, and more preferably 98 mol% or more. Moreover, it is preferable that average polymerization degree is 50-2000, and it is more preferable that it is 200-1000.

  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 plastic 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 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 alone or 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 silicon, aluminum, titanium, and zirconium, the halogen includes chlorine, iodine, bromine, and the like, and the functional group having reactivity with a carboxyl group is an epoxy group. , Amino group, isocyanate group, ureido group and the like, and alkyl group includes 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 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.

  The gas barrier layer (II) in the present invention has a heat stabilizer, an antioxidant, a reinforcing material, a pigment, an anti-degradation agent, a weather resistance, as long as the gas barrier property and the adhesiveness to the plastic substrate (I) are not significantly impaired. An 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 the heat stabilizer, antioxidant, and deterioration inhibitor 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 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 plastic substrate (I) is preferably thicker than 0.05 μm in order to sufficiently enhance the gas barrier property of the gas barrier laminate, from the economical viewpoint. Therefore, 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 gas barrier layer (II) forming coating solution on the plastic 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, the gas barrier property of the obtained gas barrier laminate can be remarkably improved by adding an appropriate amount of an alkali compound. 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 may be any as long as it does not inhibit the gas barrier properties of the resulting gas barrier laminate, and examples include inorganic substances such as sodium hydroxide and calcium hydroxide, and organic substances such as ammonia, methylamine, and diethanolamine, Ammonia is preferable because it is easily volatilized by 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, making it difficult to form the gas barrier layer (II) on the plastic substrate (I).

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

  After the coating liquid for forming the gas barrier layer (II) is applied to the plastic substrate (I), heat treatment may be performed immediately to form a dry film and heat treatment at the same time. Heat treatment may be performed after moisture or the like is evaporated by spraying 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 plastic substrate (I) after applying the gas barrier layer (II) forming coating solution. In any of the above cases, it is preferable that the plastic substrate (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 be sufficiently advanced, and it may be difficult to obtain a laminate having sufficient gas barrier properties, while it is too high. And there exists a possibility that gas barrier layer (II) etc. may become embrittled. 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 cross-linking reaction cannot proceed sufficiently, and it becomes difficult to obtain a laminate having gas barrier properties. On the other hand, if it is too long, productivity decreases.

  The coating liquid for forming the gas barrier layer (II) applied to the plastic 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. 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 of the present invention has the above-described configuration, it has excellent gas barrier properties. The gas barrier laminate that has been subjected to hydrothermal treatment at 95 ° C. for 30 minutes has an atmosphere of 20 ° C. and a relative humidity of 65%. the in measured oxygen ^{permeability, 200mL / (m 2 · day} · MPa) can be less, the oxygen permeability is preferably ^{0.01~200mL / (m 2 · day ·} MPa), More preferably, it is 0.01-100 mL / (m < ² > * day * MPa).

  The gas barrier laminate of the present invention preferably has a tensile strength of 150 MPa or more, and more preferably 180 MPa or more. If the tensile strength is less than 150 MPa, the mechanical strength is not sufficient, and the piercing strength tends to decrease. In addition, the tensile elongation is preferably 60% or more, and more preferably 80% or more, from the same viewpoint as the tensile strength.

  The pinhole resistance of the gas barrier laminate of the present invention is preferably 100 or less, more preferably 20 or less, in the 500 times repeated bending fatigue test at 5 ° C. preferable. Specifically, the pinhole resistance is Fed. Shown in MIL-B-131F. Test Method Std. In accordance with Method 2017 of 101C, a sample of 12 inches × 8 inches is gripped in a cylindrical shape with a diameter of 3.5 inches, with an initial gripping distance of 7 inches and a gripping distance of 1 inch at maximum bending, a so-called gel bot tester (manufactured by Rigaku Corporation) The number of pinholes generated after being bent 500 times at 5 ° C. was measured and evaluated.

  The transparency of the gas barrier laminate of the present invention is preferably 70% or less of haze, more preferably 50% or less, further preferably 30% or less, and 15% or less. Particularly preferred is 10% or less. However, this is not the case because transparency may not be required depending on the application.

  The gas barrier laminate of the present invention can be produced by the following method.

  The plastic substrate (I) made of a single layer film is made of, for example, a thermoplastic resin mixed with a metal compound, heated and melted with an extruder and extruded into a film from a T-die, air knife casting method, electrostatic application It cools and solidifies on the cooling drum rotated by well-known casting methods, such as the casting method, and the film of the unstretched plastic base material (I) is obtained.

  In addition, the plastic substrate (I) composed of a multilayer film, for example, heat-melts a thermoplastic resin mixed with a metal compound in the extruder A, and heat-melts the thermoplastic resin in the extruder B, respectively. By superposing two types of melted resins in a die, for example, extruding a film having a two-layer structure of metal-containing layer (M) / resin layer (R) from a T-die, and cooling and solidifying in the same manner as above, It can be obtained in a stretched state.

  By including the metal compound in the plastic substrate (I) by such a method, the step of laminating the layer containing the 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. By performing simultaneous biaxial stretching in the machine direction (MD) and the transverse direction (TD), a gas barrier laminate that has been biaxially stretched can be obtained. Further, after stretching the obtained unstretched film to MD, the gas barrier layer (II) is formed by applying the gas barrier layer (II) forming coating solution by the above-described method, and then stretching the TD. A gas barrier laminate that is successively biaxially stretched can be obtained. 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.

  When using a polyamide resin as the thermoplastic resin, transfer the unstretched film to a water tank whose temperature is adjusted so as not to exceed 80 ° C., and subject it to a water immersion treatment within 5 minutes and a moisture absorption treatment of 0.5 to 15%. Is preferred.

  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, a gas barrier laminate having excellent mechanical properties can be obtained.

  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 is 0 to 10%, preferably 2 to 6% as necessary. Alternatively, MD 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. In general, the simultaneous biaxial stretching method can 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 of the present invention 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 plastic 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 laminate of the present invention may be subjected to surface treatment such as corona discharge treatment, if necessary.

  The gas barrier laminate of the present invention can be made into various laminated films by laminating a resin layer such as a sealant. The resin used as the sealant is low density polyethylene, medium density polyethylene, high density polyethylene, linear low density polyethylene, polypropylene, polyethylene / polypropylene copolymer, ethylene-vinyl acetate copolymer, ionomer resin, ethylene-acrylic acid. / Methacrylic acid copolymer, ethylene-acrylic acid / methacrylic ester copolymer, polyvinyl acetate resin, etc., polyethylene, polypropylene, polyethylene / polypropylene copolymer, etc. with high heat seal strength and material strength The polyolefin resin is preferred. These resins may be used alone, or may be copolymerized or melt-mixed with other resins, or may be further acid-modified.

  As a method for forming a sealant layer in a gas barrier laminate, a film or sheet made of a sealant resin is laminated to the gas barrier laminate via an adhesive, or the sealant resin is extruded and laminated to the gas barrier laminate. And the like. In the former method, the film or sheet made of the sealant resin may be in an unstretched state or in a stretched state at a low magnification, but practically preferably in an unstretched state.

  Although the thickness of a sealant layer is not specifically limited, It is preferable that it is 20-100 micrometers, and it is more preferable that it is 40-70 micrometers.

  A packaging bag can be produced using the gas barrier laminate of the present invention, and this packaging bag is, for example, a food / beverage product, fruit, juice, drinking water, liquor, cooked food, aquatic product, frozen food. , Meat products, boiled foods, rice cakes, liquid soups, seasonings, other various foods and drinks, liquid detergents, cosmetics, and chemical products can be filled and packaged.

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

1. Measurement Method (1) Average Particle Size A cumulative percent value of 50% in a particle size distribution (volume distribution) curve measured with a laser particle size analyzer “Microtrac HRA” (manufactured by Nikkiso Co., Ltd.) was determined. A sample for measuring the average particle diameter was prepared by adding 50 g of isopropanol to 0.5 g of the metal compound and performing ultrasonic dispersion treatment for 3 minutes.

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

(3) Oxygen permeability After the obtained gas barrier laminate 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, and oxygen produced by Mocon Co. Using a barrier measuring device (OX-TRAN 2/20), the 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).

2. Raw materials The raw materials used in the following examples and comparative examples are as follows.
(1) Thermoplastic resin for construction of plastic substrate (I) PA6: Polyamide 6 resin (A1030BRF, manufactured by Unitika Ltd., relative viscosity 3.0)
PET: Polyethylene terephthalate resin (UT-CBR intrinsic viscosity 0.62 manufactured by Unitika)

(2) Metallic compound / magnesium oxide (PUREMAG FNM-G average particle size 0.4 μm, manufactured by Tateho Chemical Industry Co., Ltd.) for plastic substrate (I) composition
・ 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.)
・ Lithium carbonate (Shiraishi Kogyo Co., Ltd. Industrial average particle size 2.9μm)
・ Sodium carbonate (Takasugi Pharmaceutical's high purity sodium carbonate)

(3) Metal compound master chip for plastic substrate (I) constitution According to Examples and Comparative Examples, 15 parts by mass of metal compound and 85 parts by mass of PA6 or PET used for the metal-containing layer (M) described in Table 1 A metal compound master chip was prepared by kneading.
In Examples 2, 10, and 13, a metal compound master chip having a mixing ratio of 50 parts by mass of lithium carbonate and 50 parts by mass of PA6 and / or a metal having a mixing ratio of 50 parts by mass of magnesium oxide and 50 parts by mass of PA6. A compound master chip was used. Moreover, about the comparative example 2, the metal compound master chip of the compounding ratio of 75 mass parts of magnesium oxide and 25 mass parts of PA6 was used.

(4) Polycarboxylic acid component / EMA aqueous solution of gas barrier layer (II) forming coating solution:
EMA (weight average molecular weight 60000) and sodium hydroxide were added to water, dissolved by heating and then cooled to room temperature. 10 mol% of the carboxyl group of EMA was neutralized with sodium hydroxide, solid content 15 Mass% EMA aqueous solution.
-PAA aqueous solution:
10 mol% of the carboxyl group of polyacrylic acid prepared with polyacrylic acid (A10H, manufactured by Toagosei Co., Ltd., number average molecular weight 200000, 25 wt% aqueous solution) and sodium hydroxide was neutralized with 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, polymerization degree 1270 to 141,000).

Example 1
PA6 and the metal compound master chip were mixed so that the lithium carbonate content was 5% 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 rapidly cooled to obtain an unstretched plastic 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 3/7, 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 gradually cooled to room temperature. A plastic substrate (I) having a thickness of 15 μm was formed on a gas barrier layer (II To obtain a gas barrier laminate.

Examples 2-6, 8-12, Comparative Examples 1, 3
As in Example 1, except that PA 6 and the metal compound master chip were appropriately used so as to have the composition described in Table 1, and the thickness after stretching was adjusted to the thickness described in Table 1. Thus, an unstretched plastic substrate (I) film was obtained and subjected to water immersion treatment.
Next, with respect to other resins and polycarboxylic acids of PVA, the gas barrier layer (II) was prepared in the same manner as in Example 1 except that the types and mass ratios (solid contents) were those shown in Table 1. A forming coating solution was prepared.
Using the obtained coating solution, in the same manner as in Example 1, after applying to an unstretched film, drying, and then biaxially stretching, a gas barrier laminate was obtained.
In Example 9, as PET was used as the thermoplastic resin, the conditions were further changed as follows. That is, an unstretched film was produced at a cylinder temperature of 280 ° C., and the obtained unstretched film was not subjected to water immersion treatment. Moreover, the temperature in simultaneous biaxial stretching was 90 degreeC, and the temperature of heat processing was 230 degreeC.

Example 7
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 (7-1) was obtained. In the APTMOS methanol solution (7-1), 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 (7-2) was obtained.
Subsequently, after the solution (7-2) 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 with stirring. A solution (7-3) was obtained.
Subsequently, 36.2 parts by mass of APTMOS methanol solution (7-1) was added while stirring the solution (7-3), and the mixture was further stirred for 30 minutes to obtain a solution (7-4).
A gas barrier laminate was obtained in the same manner as in Example 5 except that the solution (7-4) prepared by the above method was used as the gas barrier layer (II) forming coating solution.

Example 13
The metal compound master chip was mixed so that the contents of lithium carbonate and magnesium oxide were 25% by mass, respectively. This mixture was put into an extruder A and melt-extruded at 260 ° C. On the other hand, PA6 was put into the extruder B and melt-extruded at 260 ° C.
Two types of resins melted in the extruder A and the extruder B are overlapped in a die, and a sheet having a two-layer structure of a metal-containing layer (M) / resin layer (R) is extruded from a T die, and a surface temperature of 20 An unstretched multi-layer film having a thickness of 150 μm was obtained by adhering to a cooling roll at 0 ° C. and having (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, 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 the surface of the metal-containing layer (M) of the unstretched multilayer film that had been subjected to water immersion treatment, 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 resin layer (R) having a thickness of 14.5 μm, and having a thickness of 15 μm. A gas barrier laminate was obtained in which a gas barrier layer (II) having a thickness of 0.3 μm was laminated on the metal-containing layer (M) of the plastic substrate (I).

Examples 14 and 15
The extrusion amounts of the extruders A and B were adjusted so that the composition shown in Table 1 was appropriately used with PA6 and the metal compound master chip, and the thickness after stretching was as shown in Table 1. Except having changed, it carried out similarly to Example 13, and obtained the unstretched multilayer film, and performed the water immersion process.
Next, a gas barrier layer (II) forming coating solution was prepared in the same manner as in Example 1.
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 was obtained.

Comparative Example 2
An unstretched polyamide base film was obtained and subjected to water immersion treatment in the same manner as in Example 1 except that a metal compound master chip containing 75% by mass of lithium carbonate was used.
Next, using the gas barrier layer (II) forming coating solution obtained in Example 1, it was applied to an unstretched film and dried in the same manner as in Example 1, and then it was attempted to simultaneously biaxially stretch. The film was broken during stretching, and a gas barrier laminate could not be obtained.

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

In Examples 1 to 15, gas barrier laminates having excellent gas barrier properties were obtained.
In Comparative Example 1, since the metal compound contained in the plastic substrate (I) was less than 0.1% by mass, a gas barrier laminate having sufficient gas barrier properties could not be obtained.
In Comparative Example 3, since the gas barrier layer (II) did not contain polycarboxylic acid, a gas barrier laminate having sufficient gas barrier properties could not be obtained.

Claims (10)

A gas barrier laminate in which a gas barrier layer (II) is laminated on a plastic substrate (I), wherein the plastic substrate (I) contains 0.1 to 70% by mass of a monovalent metal compound, A gas barrier laminate, wherein the layer (II) contains a polycarboxylic acid. The gas barrier laminate according to claim 1, wherein the plastic substrate (I) is a multilayer film, and at least one layer thereof contains a monovalent metal compound in an amount of 0.1 to 70% by mass. The plastic substrate (I) further contains a divalent or higher-valent metal compound, and contains a monovalent metal compound and a divalent or higher-valent metal compound in an amount of 0.1 to 70% by mass. The gas barrier laminate according to claim 1 or 2. The gas barrier laminate according to any one of claims 1 to 3, wherein the thermoplastic resin constituting the plastic substrate (I) is a polyamide resin or a polyester resin. The gas barrier layered product according to any one of claims 1 to 4, wherein the gas barrier layer (II) contains a polyalcohol. The gas barrier laminate according to any one of claims 1 to 5, wherein the metal constituting the monovalent metal compound is lithium or sodium. The gas barrier laminate according to any one of claims 3 to 6, wherein the metal constituting the divalent or higher metal compound is magnesium, calcium, or zinc. The oxygen permeability under an atmosphere of 20 ° C and 65% relative humidity after hot water treatment at 95 ° C for 30 minutes is 200 mL / (m ² · day · MPa) or less. The gas barrier laminate according to any one of the above. The gas barrier laminate according to any one of claims 1 to 8, wherein the gas barrier laminate is simultaneously or sequentially biaxially stretched. A packaging bag comprising the gas barrier laminate according to claim 1.