JP6522958B2 - Gas barrier mat film - Google Patents

Description

  The present invention relates to a gas barrier mat film.

  Plastic films such as polyamide films are used in a wide range of applications as packaging materials because they are excellent in strength and formability. In recent years, plastic films are required to have a matted film surface from the viewpoint of enhancing the designability, and in order to enhance the preservability in packaging applications such as food and medical products, it is also required to have gas barrier properties. . Above all, in packaging films such as foods containing water, gas barrier properties under high humidity are also required.

  As a matte film having gas barrier properties, for example, in Patent Document 1, a matte layer is provided on at least one side of a plastic film substrate, and a hydrolyzate of alkoxysilane and / or alkoxysilane polycondensate, and polyvinyl alcohol A film coated with a coating comprising a mixture is disclosed. However, since the matte film having gas barrier properties described in Patent Document 1 contains polyvinyl alcohol in the coating agent, the gas barrier properties under high humidity are low.

JP, 2013-184415, A

  An object of the present invention is to solve the above problems and to provide a matte film having excellent gas barrier properties even under high humidity.

As a result of intensive studies on the above problems, the present inventors further laminated a gas barrier layer containing a polycarboxylic acid on a matte film containing a metal compound to provide a matte film having excellent gas barrier properties even under high humidity. It has been found that the present invention can be obtained.
That is, the gist of the present invention is as follows.
(1) A gas barrier mat film comprising a gas barrier layer (II) laminated on a plastic substrate (I),
The plastic substrate (I) is a biaxially stretched film, has a metal-containing layer containing 0.1 to 70% by mass of a metal compound , and the metal-containing layer is provided in contact with the gas barrier layer (II) Yes,
The metal constituting the metal compound is magnesium,
The gas barrier layer (II) contains a polycarboxylic acid,
A gas barrier matte film characterized in that the surface glossiness on the plastic substrate (I) side is 70% or less.
(2) The gas barrier mat film according to (1), wherein the thermoplastic resin constituting the plastic substrate (I) is a polyamide resin or a polyester resin.
(3) The gas barrier matte film according to (1) or (2), which is biaxially stretched simultaneously or sequentially.
(4) A packaging bag comprising the gas barrier mat film according to any one of (1) to (3).

  The gas barrier mat film of the present invention has excellent gas barrier properties even under high humidity, has a low glossiness on the film surface, and has a sufficient matte tone. Therefore, it can be used in a wide range of applications as a packaging material.

Hereinafter, the present invention will be described in detail.
The gas barrier mat film of the present invention is a film in which a gas barrier layer (II) is laminated on a plastic substrate (I), and the plastic substrate (I) contains a metal compound.

  The thermoplastic resin constituting the plastic base material (I) includes polyolefin resins such as polyethylene, polypropylene and ionomer, nylon 6, nylon 66, nylon 46, nylon 46, nylon MXD 6, nylon 9 T and other polyamide resins, polyethylene terephthalate, polyethylene isophthalate , Polyester resins such as polyethylene naphthalate, polytrimethylene terephthalate, polytrimethylene naphthalate, polybutylene terephthalate, polybutylene naphthalate, polylactic acid, vinyl chloride, polystyrene resin, polycarbonate resin, polyarylate resin, ethylene-vinyl acetate co Polymers, ethylene-vinyl alcohol copolymers or mixtures thereof may be mentioned. Among these thermoplastic resins, when a packaging bag is formed, a polyamide resin is preferable because it is excellent in piercing strength, impact resistance and the like, and nylon 6 is preferable among them. In addition, polyester resins are preferable, and polyethylene terephthalate is particularly preferable, from the viewpoints of excellent heat resistance and economical efficiency.

  The metal constituting the metal compound may be a monovalent metal such as lithium, sodium, potassium, rubidium or cesium, or a divalent or higher metal such as magnesium, calcium, zirconium, zinc, copper, cobalt, iron, nickel or aluminum. Can be mentioned. Among them, metals having high ionization tendency are preferable from the viewpoint of easy reaction with carboxylic acid, and monovalent or divalent metals are 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, and may be two or more.

  In the present invention, the metal compound is a compound containing the above metal, and as the compound, oxides, hydroxides, halides, inorganic salts such as carbonates, hydrogencarbonates, phosphates, sulfates and the like, And acetates, formates, stearates, citrates, malates, carboxylates such as maleates and organic acid salts such as sulfonates, preferably oxides and carbonates. . Also, a single metal may be used as the metal compound.

  Among the above-mentioned metal compounds, preferred examples are lithium carbonate, sodium hydrogencarbonate, magnesium oxide, 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 and the like can be mentioned, and from the viewpoint of gas barrier properties, divalent metal compounds of magnesium oxide, magnesium carbonate, magnesium hydroxide, magnesium acetate, calcium carbonate, calcium acetate, zinc oxide Is preferred. The metal compounds may be used alone or in combination.

  The metal compound is preferably in the form of powder, 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, 0 The thickness is more preferably 0.1 to 2.0 μm, and particularly preferably 0.05 to 1.0 μm. Metal compounds having an average particle size of less than 0.001 μm tend to aggregate due to their large surface area, and coarse aggregates may be dispersed in the film, which may lower the mechanical properties of the substrate. On the other hand, the plastic substrate (I) containing a metal compound having an average particle size of more than 10.0 μm tends to be broken at a high frequency during film formation, and the productivity tends to decrease.

  The metal compound can be improved in dispersibility, weatherability, 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, zinc oxide treatment and the like. Examples of the organic treatment include treatment with a fatty acid compound, a polyol compound such as pentaerythritol or trimethylolpropane, an amine compound such as triethanolamine or trimethylolamine, or a silicone compound such as a silicone resin or alkylchlorosilane. .

  Content of the metal compound in plastic base material (I) needs to be 0.1-70 mass%, and it is preferable that it is 0.1-50 mass%, 0.2-20 mass% Is more preferably 0.5 to 10% by mass. The gas barrier mat film obtained as content of the metal compound in plastic base material (I) is 0.1-70 mass% can acquire the outstanding gas barrier property. 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 of the gas barrier layer (II) is reduced, and thus obtained. The film has low gas barrier properties. On the other hand, the plastic substrate (I) having a content of more than 70% by mass has a high frequency of breakage in stretching at the time of film formation, the productivity is lowered, and the mechanical properties are also lowered.

  The surface gloss of the gas-barrier matte film of the present invention on the plastic substrate (I) side needs to be 70% or less, preferably 50% or less, and more preferably 30% or less. When the surface glossiness exceeds 70%, the matte tone may be insufficient, and a high-grade impression which is the desired design may not be obtained.

  In order to make the surface glossiness on the plastic substrate (I) side 70% or less, in the plastic substrate (I), silica-alumina clay mineral (hydrous aluminum silicates), silica-magnesium, inorganic It is preferable that additives such as lubricants and high molecular weight organic lubricants are contained. Silica-alumina clay minerals include clay, kallion and calcined kaolin, silica-magnesium includes talc, inorganic lubricants include silica and titanium oxide, and polymer organic lubricants And acrylic organic lubricants and polystyrene organic lubricants. Among them, talc, kaolin, calcined kaolin, and silica are preferable from the viewpoint of easy dispersibility, and silica is more preferable because it is excellent in design. The particle size of these additives is preferably 0.5 to 5.0 μm. If the particle size is less than 0.5 μm, projections on the film surface are less likely to be formed, and the surface gloss tends to exceed 70%. On the other hand, when the particle size exceeds 5.0 μm, the mechanical properties of the obtained film may be deteriorated.

  The content of the additive is preferably 0.5 to 50% by mass, preferably 0.8 to 20% by mass, and 1.0 to 5% by mass in the plastic base material (I). It is more preferable that When the content of the additive is 0.5% by mass, projections of the film surface are less likely to be formed, and the surface glossiness tends to exceed 70%. On the other hand, if the content of the additive exceeds 50% by mass, the frequency of breakage in stretching at the time of film formation becomes high, the productivity is lowered, and the mechanical properties of the obtained film are also lowered.

  The plastic substrate (I) may be a single layer film or a multilayer film. When the plastic substrate (I) is a monolayer film, the metal compound is required to be contained in an amount of 0.1 to 70% by mass in the monolayer film. When it is a multilayer film, it is necessary to contain 0.1-70 mass% in the at least one layer.

  Hereinafter, the configuration of the multilayer film will be described. The layer containing the metal compound in the multilayer film is referred to as "metal-containing layer (M)", and the other layers are referred to as "resin layer (R)". When the plastic substrate (I) is a multilayer film, the gas barrier layer (II) and the metal-containing layer (M) of the plastic substrate (I) are in contact as a constitution of the gas barrier mat film obtained. , (R) / (M) / (II), (M) / (R) / (M) / (II), (II) / (M) / (R) / (M) / (II) And the like. In these configurations, the gas barrier layer (II) and the metal-containing layer (M) are in contact with each other, and the polycarboxylic acid in the gas barrier layer (II) easily reacts with the metal compound in the metal-containing layer (M), Gas barrier properties can be obtained efficiently. Among them, the configuration of (R) / (M) / (II) is preferable in consideration of equipment for production and operability.

The additive for reducing the surface gloss may be contained in any of the metal-containing layer (M) and the resin layer (R) described above, and may be contained in both layers.
Above all, the gas barrier mat film of the present invention has a configuration in which an additive for reducing the surface gloss is added only to (R) in the configuration of (R) / (M) / (II). Is preferred because it is the best.
When an additive for reducing the surface gloss is added to the layer adjacent to the gas barrier layer (II), the gas barrier layer (II) after stretching becomes thinner due to the unevenness due to the inclusion of the additive, It is not preferable because there is a concern that perforation may occur and the gas barrier properties may decrease.

  When the gas barrier mat film of the present invention has a constitution of (R) / (M) / (II) and an additive for decreasing the surface gloss is added only to (R), a multilayer film The thickness ratio of the metal-containing layer (M) to the resin layer (R) is preferably 1/10 to 100/1, and more preferably 1/10 to 10/1.

  In addition to the additives described above, the thermoplastic resin constituting the plastic base material (I) may, if necessary, be a heat stabilizer or an antioxidant as long as the performance of the plastic base material (I) is not adversely affected. Add one or more of various additives such as reinforcing agents, reinforcing agents, pigments, antidegradants, weathering agents, flame retardants, plasticizers, preservatives, UV absorbers, antistatic agents, antiblocking agents, etc. May be

  The method for causing the thermoplastic resin to contain the metal compound and the additive is not particularly limited, and the thermoplastic resin can be blended at any time of the production process. For example, a method of adding when polymerizing a thermoplastic resin constituting the plastic base material (I), a method of kneading with a thermoplastic resin and an extruder, or a masterbatch which is kneaded with high concentration and mixed The method (master batch method) etc. which add and dilute this to a thermoplastic resin are mentioned. In the present invention, a masterbatch method is preferably employed.

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

  The gas barrier layer (II) constituting the gas barrier mat film 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 copolymer, polysaccharides having a carboxyl group in a side chain such as alginic acid, polyamides having a carboxyl group, polyesters, and the like. The above polycarboxylic acids may be used alone or in combination.

  When the polycarboxylic acid is a polymer, its weight average molecular weight is preferably 1,000 to 100,000, more preferably 10,000 to 150,000, and still more preferably 1,500 to 110,000. When the weight average molecular weight of the polycarboxylic acid is too low, the resulting gas barrier layer (II) becomes brittle, while when the molecular weight is too high, the handling property is impaired, and in some cases, the gas barrier layer (II) described later The gas barrier layer (II) obtained by aggregating in the coating liquid for forming may lose the gas barrier properties.

  In the present invention, among the above-mentioned polycarboxylic acids, polyacrylic acid and olefin-maleic acid copolymer, particularly ethylene-maleic acid copolymer (hereinafter sometimes abbreviated as EMA), from the viewpoint of gas barrier properties, 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 form a maleic anhydride structure in which adjacent carboxyl groups are dehydrated and cyclized in the dry state, and opens in a wet state or in an aqueous solution to form a maleic acid structure. 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, still more preferably 30 mol% or more, and most preferably 35 mol% or more. . The weight average molecular weight of EMA is preferably 1000 to 1000000, more preferably 3000 to 500,000, still more preferably 7,000 to 300,000, and particularly preferably 10,000 to 200,000.

  In the present invention, the gas barrier layer (II) preferably contains a polyalcohol. By containing a polyalcohol, the polycarboxylic acid in the gas barrier layer (II) reacts with the polyalcohol in addition to the reaction with the metal compound in the plastic substrate (I), thereby improving the gas barrier properties. be able to. Polyalcohols are compounds having two or more hydroxyl groups in the molecule, and as low molecular weight compounds, glycerol, sugar alcohols such as pentaerythritol, monosaccharides such as glucose, disaccharides such as maltose, oligosaccharides such as galactooligosaccharides Sugars can be mentioned, and as the polymer compound, polysaccharides such as polyvinyl alcohol, ethylene-vinyl alcohol copolymer, starch and the like can be mentioned. The above polyalcohols may be used alone or in combination. The degree of saponification of the 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 to 20, and 0. The content is more preferably 0.1 to 10, more preferably 0.02 to 5, and most preferably 0.04 to 2.

  Further, 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 compounds in the plastic substrate (I), so It can be improved.

  The polyamine has two or more of at least one amino group selected from primary and secondary as an amino group in the molecule, and specific examples thereof include polyallylamine, polyvinylamine, branched polyethyleneimine And linear polyethylenimine, polylysine, polysaccharides having an amino group in a side chain such as chitosan, polyamides having an amino group in a side chain such as polyarginine, and the like. 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 brittle, while if the molecular weight is too high, the handling property is impaired, and in some cases, the gas barrier layer (II) described later is formed. The gas barrier layer (II) obtained by aggregating in a coating solution for the purpose may lose the gas barrier properties.

  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. When the mass ratio of the polyamine is lower than this, crosslinking of the carboxyl group of the polycarboxylic acid is insufficient, and conversely, when the mass ratio of the polyamine is higher than this, the crosslinking of the amino group of the polyamine becomes insufficient. Also, the gas barrier mat film obtained may be inferior in gas barrier property.

  The gas barrier layer (II) in the present invention may contain a crosslinking agent. The gas barrier properties can be enhanced by containing a crosslinking agent. It is preferable that it is 0.1-30 mass parts with respect to 100 mass parts of polycarboxylic acids, and, as for content of the crosslinking agent in gas barrier layer (II), it is more preferable that it is 1-20 mass parts.

  Examples of the crosslinking agent include compounds having a self-crosslinking property and compounds having a plurality of functional groups that react with carboxyl groups in the molecule, and when the gas barrier layer (II) contains a polyalcohol, it reacts with hydroxyl groups. It may be a compound having a plurality of functional groups in the molecule. Specific examples of the crosslinking agent preferably include isocyanate compounds, melamine compounds, urea compounds, epoxy compounds, carbodiimide compounds, zirconium salt compounds such as ammonium zirconium carbonate, metal alkoxides and the like. These crosslinking agents may be used alone or in combination.

  The metal alkoxide is a compound containing a metal to which an alkoxy group is bound, and an alkyl group substituted with a functional group having reactivity with a halogen or a carboxyl group may be bound instead of a part of the alkoxy group. . Here, metals include atoms such as silicon, aluminum, titanium and zirconium, halogens include chlorine, iodine, bromine and the like, and functional groups having reactivity with carboxyl groups are epoxy groups And an amino group, an isocyanate group, a ureido group and the like, and an alkyl group includes a methyl group, an ethyl group, an n-propyl group, an iso-propyl group, an n-butyl group, an 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 and 3-isocyanatopropyltriethoxysilane, alkoxytitanium compounds such as tetraisopropoxytitanium and tetraethoxytitanium, and alkoxylose such as triisopropoxyaluminum Aluminum compounds and alkoxyzirconium compounds such as tetraisopropoxyzirconium are mentioned.

  These metal alkoxides should be used in the form of partially or wholly hydrolyzed, partially hydrolyzed or condensed, completely hydrolyzed and partially condensed or a combination thereof. You can also.

  When the metal alkoxide and the polycarboxylic acid are mixed, it may be difficult for both to react and coat, so it is preferable to form a hydrolytic condensate beforehand and then to mix. As a method of forming a 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, a heat stabilizer, an antioxidant, a reinforcing material, a pigment, an antidegradant, weather resistance, as long as the gas barrier property and the adhesion with the plastic substrate (I) are not significantly impaired. Agents, flame retardants, plasticizers, mold release agents, lubricants, preservatives, antifoam agents, wetting agents, viscosity modifiers and the like may be added.

  Examples of heat stabilizers, antioxidants and antidegradants include hindered phenols, phosphorus compounds, hindered amines, sulfur compounds, copper compounds, halides of alkali metals and the like, and these may be mixed and used. May be

  As the reinforcing material, for example, clay, talc, wollastonite, silica, alumina, calcium silicate, sodium aluminate, sodium aluminosilicate, magnesium silicate, glass balloon, carbon black, zeolite, montmorillonite, hydrotalcite, fluorine mica, Metal fibers, metal whiskers, ceramic whiskers, potassium titanate whiskers, boron nitride, graphite, glass fibers, carbon fibers, fullerenes (C60, C70, etc.), carbon nanotubes, etc. may be mentioned.

  The thickness of the gas barrier layer (II) to be laminated on the plastic substrate (I) in the present invention is preferably thicker than 0.05 μm in order to sufficiently enhance the gas barrier properties of the gas barrier mat film, which is economical Therefore, it is preferable to be thinner than 5.0 μm.

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

  In the present invention, when a polycarboxylic acid and a polyalcohol are mixed to prepare an aqueous coating solution, it is preferable to add an alkaline compound in an amount of 0.1 to 20 equivalent% to the carboxyl group of the polycarboxylic acid. . The polycarboxylic acid has high hydrophilicity when the content of the carboxyl group is large, so it can be made into an aqueous solution without adding an alkali compound. However, the gas barrier properties of the obtained gas barrier mat film can be remarkably improved by adding an appropriate amount of the alkali compound. The alkali compound may be any one as long as it can neutralize the carboxyl group of the polycarboxylic acid, and among them, alkali compounds of monovalent metals and ammonia are preferable, and as alkali compounds of monovalent metals, potassium hydroxide and sodium hydroxide are preferable. More preferable. It is preferable that these addition amounts are 0.1-20 mol% with respect to the carboxyl group of polycarboxylic acid.

  The preparation of the coating solution can be carried out by a known method using a dissolver equipped with a stirrer, etc. For example, the polycarboxylic acid and the polyalcohol are separately made into an aqueous solution and mixed before coating The method is preferred. At this time, if the above alkali compound is added to the aqueous solution of polycarboxylic acid, the stability of the aqueous solution can be improved.

  Further, in the present invention, when an aqueous coating liquid is prepared by mixing a polycarboxylic acid and a polyamine, in order to suppress gelation, it is preferable to add a base to the polycarboxylic acid. The base may be any base that does not inhibit the gas barrier properties of the gas barrier mat film obtained, and examples thereof include inorganic substances such as sodium hydroxide and calcium hydroxide, and organic substances such as ammonia, methylamine and diethanolamine, and the like. Ammonia is preferable because it is easily volatilized by heat treatment. The amount of the base added is preferably 0.6 equivalents or more, more preferably 0.7 equivalents or more, and still more preferably 0.8 equivalents or more with respect to the carboxyl group of the polycarboxylic acid. . When the amount of the base added is small, the coating liquid may gel during coating, and it may be difficult to form the gas barrier layer (II) on the plastic substrate (I).

  The method for applying the coating liquid for forming the gas barrier layer (II) 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 A die coater or the like, 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 carried out immediately to form a dry film and heat treatment simultaneously, or after application, hot air with a dryer or the like After forming a dry film by evaporating water or the like by spraying or infrared irradiation, the heat treatment may be performed. It is preferable to carry out heat treatment immediately after coating, as long as there is no particular hindrance to physical properties such as the state of the gas barrier layer (II) and the gas barrier property. The heat treatment method is not particularly limited, and examples thereof include a method of heat treatment in a dry atmosphere such as an oven. In consideration of shortening of the process and the like, it is preferable to stretch the plastic substrate (I) after applying the coating liquid for forming the gas barrier layer (II). In any of the above cases, the plastic substrate (I) on which the gas barrier layer (II) is formed is preferably subjected to heat treatment for 5 minutes or less in a heating atmosphere at 100 ° C. or more.

  In the case where the gas barrier layer (II) contains a polycarboxylic acid and a polyalcohol, the gas barrier layer (II) can also be affected by the ratio thereof, the presence or absence of added components, and the content thereof. Although the heat processing temperature can not generally be said, it is preferable that it is 100-300 degreeC, It is more preferable that it is 120-250 degreeC, It is more preferable that it is 140-240 degreeC, It is 160-220 degreeC Is particularly preferred. If the heat treatment temperature is too low, the cross-linking reaction of the polycarboxylic acid and the polyalcohol can not proceed sufficiently, which may make it difficult to obtain a laminate having sufficient gas barrier properties, while being too high. And the gas barrier layer (II) and the like may become brittle. The heat treatment time is preferably 5 minutes or less, more preferably 1 second to 5 minutes, still more preferably 3 seconds to 2 minutes, and particularly preferably 5 seconds to 1 minute . If the heat treatment time is too short, the above-mentioned crosslinking reaction can not be sufficiently progressed, and it becomes difficult to obtain a laminate having gas barrier properties. On the other hand, if it is too long, the productivity is lowered.

  In addition, the coating solution for forming the gas barrier layer (II) applied to the plastic substrate (I) is subjected to high energy radiation such as ultraviolet light, X-ray, electron beam, etc. before and after the above drying, as necessary. It may be done. In such a case, a component that is crosslinked or polymerized by high energy radiation may be blended.

The gas barrier mat film of the present invention is excellent in gas barrier properties because it has the above-mentioned constitution, and the hot water treated gas barrier mat film of 95 ° C. for 30 minutes has an atmosphere of 20 ° C. and a relative humidity of 65%. the in measured oxygen ^{permeability, 300mL / (m 2 · day} · MPa) can be less, the oxygen permeability, it is ^{1 × 10 -2 ~300mL / (m} 2 · day · MPa) Preferably, it is 1 × 10 ^{−2 to} 200 mL / (m ² · day · MPa), and more preferably 1 × 10 ^{−2 to} 100 mL / (m ² · day · MPa).

The gas barrier mat film of the present invention preferably has a tensile strength of 150 MPa or more, more preferably 180 MPa or more. If the tensile strength is less than 150 MPa, the mechanical strength is insufficient and the puncture strength tends to be reduced. Further, the tensile elongation is preferably 60% or more, more preferably 80% or more, from the same viewpoint as the tensile strength.

  The haze of the gas barrier mat film of the present invention is preferably 10% or more, more preferably 30% or more, and still more preferably 50% or more.

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

  The plastic base material (I) made of a film having a single layer structure is, for example, a thermoplastic resin mixed with a metal compound and an additive, heated and melted by an extruder, and extruded as a film from a T-die; The film is cooled and solidified on a rotating cooling drum by a known casting method such as electrostatic application casting method to obtain a film of an unstretched plastic substrate (I).

  Further, the plastic base material (I) comprising a film having a multilayer structure is, for example, a thermal resin obtained by heating and melting a thermoplastic resin mixed with a metal compound with an extruder A and mixing an additive for reducing surface glossiness The plastic resin is heated and melted by the extruder B, and the two melted resins are superposed in a die, for example, a metal-containing layer (M) / resin layer (R) two-layer film from a T-die It can be obtained in the unstretched state by extruding and cooling and solidifying as described above.

  The obtained single layer or multilayer unstretched film is coated with the coating solution for forming a gas barrier layer (II) by the method described above to form a gas barrier layer (II), and a tenter type simultaneous biaxial stretching machine By performing simultaneous biaxial stretching in the machine direction (MD) and the transverse direction (TD), a simultaneously biaxially stretched gas barrier mat film can be obtained. Further, the obtained unstretched film is stretched in MD, and then the coating solution for forming a gas barrier layer (II) is applied by the method described above to form a gas barrier layer (II), and then stretching is performed in TD, A gas barrier matte film can be obtained which has been sequentially biaxially stretched. In addition, since stretchability may fall in a post process when an unstretched film is orientated, it is preferable that an unstretched film is a substantially amorphous and non-oriented state.

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

  Further, the stretching ratio of the film is preferably 1.5 times or more in the case of uniaxial stretching, and is preferably 1.5 times or more each in the longitudinal and transverse directions also in the case of longitudinal and transverse biaxial stretching. Usually, it is preferably 3 times or more, more preferably 6 to 20 times, and still more preferably 6.5 to 13 times. It becomes possible to obtain the gas-barrier mat film of the outstanding mechanical property as a draw ratio is this range.

  The film subjected to the drawing process is heat-set at a temperature of 150 to 300 ° C. in the tenter subjected to the drawing process, if necessary, in the range of 0 to 10%, preferably 2 to 6%. Or relaxation treatment of TD is applied. 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 to perform the heat relaxation treatment at a temperature lower than the maximum temperature of the heat setting process.

  Although the stretching method is not particularly limited, it is preferable to use the simultaneous biaxial stretching method. The simultaneous biaxial stretching method can generally have practical properties such as mechanical properties, optical properties, thermal dimensional stability, and pinhole resistance. In addition, in the sequential biaxial stretching method in which longitudinal stretching is followed by transverse stretching, orientation crystallization of the film proceeds during longitudinal stretching and the stretchability of the thermoplastic resin during transverse stretching decreases, so that the compounding of the metal compound is performed. When the amount is large, the breakage frequency of the film tends to be high. For this reason, in the present invention, it is preferable to carry out a water absorption treatment and to adopt a simultaneous biaxial stretching method.

  The gas barrier mat film of the present invention can also be treated in a humidified atmosphere after producing a laminate for the purpose of enhancing the gas barrier properties. The action of the metal compound of the plastic base material (I) and the polycarboxylic acid of the gas barrier layer (II) can be further promoted by the humidification treatment. In such humidification treatment, the laminate may be left in an atmosphere under high temperature and high humidity, or the laminate may be brought into direct contact with high temperature water. Humidification treatment conditions vary depending on the purpose, but when left under 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, about 30-130 degreeC (100 degreeC or more is under pressure) is preferable. Although the humidification treatment time varies depending on the treatment conditions, a range of several seconds to several hundred hours is generally selected.

  The gas barrier mat film of the present invention may be subjected to surface treatment such as corona discharge treatment, if necessary.

  The gas barrier mat film of the present invention can be made into various laminated films by laminating a resin layer such as a sealant.

  As a resin used as a sealant, 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 acid ester copolymer, polyvinyl acetate resin, etc., and polyethylene, polypropylene, polyethylene / polypropylene copolymer, etc. having high heat seal strength and high strength of the material itself Polyolefin resins are preferred. These resins may be used alone, or may be copolymerized or melt mixed with other resins, or may be further acid-modified or the like.

  As a method of forming a sealant layer on a gas barrier mat film, a method of laminating a film or sheet made of a sealant resin on a gas barrier mat film through an adhesive, extrusion laminating of a sealant resin on a gas barrier mat film 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 it is preferably in the unstretched state.

  The thickness of the sealant layer is not particularly limited, but is preferably 20 to 100 μm, and more preferably 40 to 70 μm.

  A packaging bag can be produced using the gas barrier mat film of the present invention, and the packaging bag is, for example, food and drink, fruit, juice, drinking water, liquor, cooked food, fish paste product, frozen food It can be filled and packaged with contents such as meat products, simmered foods, rice bran, liquid soap, seasonings and various other food and drink products, liquid detergents, cosmetics and chemical products.

  EXAMPLES The present invention will next be described in more detail by way of examples, which should not be construed as limiting the invention thereto.

1. Measurement Method (1) Average Particle Size The value of 50% cumulative percentage in the particle size distribution (volume distribution) curve measured by a laser type particle size analyzer “Microtrac HRA” (manufactured by Nikkiso Co., Ltd.) was determined. A sample for measuring the average particle size 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 The obtained gas barrier mat film was left in an environment of 23 ° C. and 50% RH for 2 hours or more, and then the cross section of the film was observed by a scanning electron microscope (SEM) to measure the thickness of each layer. .

(3) Haze Measurement of total light transmittance (Tt) and diffuse transmittance (Td) of the obtained gas barrier mat film according to JIS K 7136 using a haze meter (NDH 4000) manufactured by Nippon Denshoku Co., Ltd. The haze was calculated based on the following equation.
Haze (%) = (Td / Tt) × 100

(4) Surface glossiness (%)
A gas barrier obtained at an incident angle of 20 ° according to JIS K 7105 using a gloss meter (VG 7000 type) manufactured by Nippon Denshoku Co., Ltd. and using GROSS METER GM-26 manufactured by Murakami Color Research Laboratory (JIS Z8741) Surface of the matte film was measured.

(5) Oxygen Permeability The obtained gas barrier mat film is treated with hot water under the conditions of 95 ° C. for 30 minutes and then left to stand in an environment of 23 ° C. and 50% RH for 2 hours or more. The oxygen permeability in an atmosphere with a temperature of 20 ° C. and a relative humidity of 65% was measured using a barrier meter (OX-TRAN 2/20). The unit is mL / (m ² · day · MPa).

2. Raw Materials Raw materials used in the following Examples and Comparative Examples are as follows.
(1) Thermoplastic resin for construction of plastic base material (I), PA6: nylon 6 resin (Unitika A1030 BRF, relative viscosity 3.0)
-PET: polyethylene terephthalate resin (UNITCA UT-CBR limiting viscosity 0.62)
(2) Additives for plastic base material (I) composition · SiO ₂ : silica (manufactured by Fuji Silysia Co., Ltd. Pyrishia 310P average particle diameter 1.4 μm)
-TiO ₂ : titanium oxide (manufactured by titanium industry KRONOS titanium oxide 1074 average particle size 0.4 μm
(3) Metal compounds for constituting plastic base material (I) MgO: magnesium oxide (manufactured by Tateho Chemical Industries, Ltd. PUREMAG FNM-G average particle diameter 0.4 μm)
・ ZnO: Zinc oxide (manufactured by Sakai Chemical Industry Co., Ltd. FINEX-50, average particle size 0.02 μm)

(4) Master chip / master chip 1 for plastic substrate (I) construction
80 parts by mass of PA6 and 20 parts by mass of SiO ₂ were kneaded to prepare a master chip.
・ Master chip 2
70 parts by mass of PA6 and 30 parts by mass of TiO ₂ were kneaded to prepare a master chip.
・ Master chip 3
80 parts by mass of PA6 and 20 parts by mass of MgO were kneaded to prepare a master chip.
・ Master chip 4
96 parts by mass of PA6 and 4 parts by mass of MgCO ₃ were kneaded to prepare a master chip.
・ Master chip 5
A master chip was produced by kneading 96 parts by mass of PA6 and 4 parts by mass of ZnO.

(5) Polycarboxylic acid component of coating liquid for forming gas barrier layer (II) · EMA aqueous solution:
EMA (weight average molecular weight 60000) and sodium hydroxide were added to water, dissolved by heating and cooled to room temperature, and 10 mol% of carboxyl groups of EMA were neutralized by sodium hydroxide, solid content 15 Mass% EMA aqueous solution.

(6) Other resin components of the coating liquid for forming the gas barrier layer (II) · PVA aqueous solution:
Polyvinyl alcohol (solid content 15% by mass) prepared by adding polyvinyl alcohol (Kovara poval 105, degree of saponification 98 to 99%, average degree of polymerization about 500) to water, heating and dissolving, and cooling to room temperature PVA) aqueous solution.

Example 1
A nylon 6 resin, master chip 1 and master chip 3 were blended, and mixed so that the content of silica was 0.5 parts by mass and the content of magnesium oxide was 0.5 parts by mass. The mixture was charged into the 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 plastic substrate (I) film with a thickness of 150 μm. The obtained unstretched film was sent to a 50 ° C. water bath and subjected to a water immersion treatment for 2 minutes.
Next, a coating solution for forming a gas barrier layer (II) having a solid content of 10% by mass is mixed with an aqueous solution of EMA and an aqueous solution of EMA so that the mass ratio (solid content) of PVA and EMA is 50/50. I got The coating liquid was applied to one surface of the water-immersed unstretched film and then dried.
The end of the film was held by the clips of a tenter-type simultaneous biaxial stretching machine, and stretched at MD at 180 ° C. and 3.3 times each in TD. Then, heat treatment is performed at 210 ° C. for 4 seconds with a TD relaxation rate of 5%, gradually cooled to room temperature, and a gas barrier layer (II having a thickness of 0.3 μm) on the plastic substrate (I) having a thickness of 15 μm. ) Was obtained to obtain a gas barrier mat film.

Examples 2 to 5 and 7 to 11 Comparative Examples 1 to 5 Reference Example 1
The gas barrier was carried out in the same manner as in Example 1 except that the type and amount of the master chip were changed and the nylon 6 resin and various master chips were mixed so that the contents of the metal compounds and additives described in Table 1 were obtained. Film was obtained.
In Example 7, the conditions were changed as follows according to using polyethylene terephthalate resin (PET) as a thermoplastic resin. 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 ° C., and the temperature of heat treatment was 230 ° C.

Example 12
Nylon 6 resin and master chip 1 were mixed such that the content of silica was 2 parts by mass. This mixture was charged into extruder A and melt extruded at 260 ° C. On the other hand, nylon 6 resin and master chip 3 were mixed such that the content of magnesium oxide was 0.5 parts by mass. This mixture was charged into an extruder B and melt extruded at 260 ° C.
Two types of resin melted respectively by extruder A and extruder B are stacked in a die, and a sheet of a two-layer structure of resin layer (R) / metal-containing layer (M) is extruded from a T die, and surface temperature 20 The film was brought into close contact with a cooling roller of 150 ° C. to obtain a 150 μm-thick unstretched multilayer film of (R) / (M) = 50/100 μm. The obtained unstretched multilayer film was sent to a 50 ° C. water bath and subjected to a water immersion treatment for 2 minutes.
Next, the coating liquid prepared in the same manner as in Example 1 was applied to the surface of the metal-containing layer (M) of the unstretched multilayer film, and then dried.
A plastic substrate having a thickness of 15 μm comprising a resin layer (R) having a thickness of 5 μm and a metal-containing layer (M) having a thickness of 10 μm subjected to simultaneous biaxial stretching and heat treatment in the same manner as in Example 1 A gas barrier matte film 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 I).

Examples 13 to 19 and Comparative Example 6
Example 12 except that the type and amount of the master chip were changed, the nylon 6 resin and the master chip were mixed, and the extrusion amount of the extruders A and B was changed so as to obtain the composition described in Table 2. Similar to the above, a gas barrier mat film was obtained.
In Example 16, the conditions were changed as follows according to using polyethylene terephthalate resin (PET) as a thermoplastic resin. 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 ° C., and the temperature of heat treatment was 230 ° C.

  The structures of the gas barrier mat films obtained in Examples and Comparative Examples and the evaluation results thereof are shown in Tables 1 and 2.

The gas barrier mat films of Examples 1 to 5 and 7 to 19 all have a surface gloss of 70% or less, an oxygen permeability of 300 mL / (m ² · day · MPa) or less, and high humidity. It had excellent gas barrier properties even below, and had excellent matte tone.

Since the gas barrier mat films of Comparative Examples 1 and 2 had a low content of silica, the surface glossiness exceeded 70%, and the matte tone was inferior. .
In the gas barrier mat film of Comparative Example 3, the additive for reducing the surface gloss was titanium oxide, so 1% by mass was blended, but the surface gloss exceeded 70%, and the matte tone was obtained. It was inferior to
The gas barrier mat film of Comparative Example 4 had a high oxygen permeability and was inferior in gas barrier properties because the content of the metal compound of the plastic base material (I) was less than 0.1% by mass.
In Comparative Example 5, the content of the metal compound of the plastic base material (I) exceeded 70% by mass, so the film was broken in stretching during film formation, and a gas barrier mat film was not obtained.
In the gas barrier mat film of Comparative Example 6, the resin layer (R) was laminated between the metal-containing layer (M) and the gas barrier layer (II), so that the surface glossiness exceeded 70%, and the matte tone was obtained. It was inferior to Furthermore, the oxygen permeability was high and the gas barrier properties were poor.

Claims (4)

A gas barrier mat film, in which a gas barrier layer (II) is laminated on a plastic substrate (I),
The plastic substrate (I) is a biaxially stretched film, has a metal-containing layer containing 0.1 to 70% by mass of a metal compound , and the metal-containing layer is provided in contact with the gas barrier layer (II) Yes,
The metal constituting the metal compound is magnesium,
The gas barrier layer (II) contains a polycarboxylic acid,
A gas barrier matte film characterized in that the surface glossiness on the plastic substrate (I) side is 70% or less.   The gas barrier mat film according to claim 1, wherein the thermoplastic resin constituting the plastic substrate (I) is a polyamide resin or a polyester resin.   The gas-barrier matte film according to claim 1 or 2, which is biaxially stretched simultaneously or sequentially.   A packaging bag comprising the gas barrier mat film according to any one of claims 1 to 3.