JP6598424B2 - Gas barrier laminate - Google Patents

Description

  The present invention relates to a gas barrier laminate.

  Packaging for foods and pharmaceuticals is highly confidential, and packaging materials using various plastic films, metal foils, paper, and other materials have been developed to prevent deterioration of contents due to moisture and oxygen. In particular, retort packaging and boil packaging that have been subjected to heat sterilization treatment such as retort and boil are generally performed as packaging forms that can be stored for a long period of time in food and pharmaceutical applications.

  The packaging materials for retort and boil are required to have various gas barrier properties, hot water resistance, fragrance retention, discoloration resistance, impact resistance, pressure resistance, puncture resistance, bending resistance, etc. A laminate structure suitable for the contents and contents is designed. For example, a biaxially stretched polyethylene terephthalate (PET) film for imparting hot water resistance, aroma retention, or printability, a biaxially stretched nylon (ONY) film for imparting impact resistance or puncture resistance, and a barrier In order to impart heat resistance, an aluminum foil (Al) or a deposited film is formed on the surface layer of the substrate, and a heat resistant grade unstretched polypropylene (CPP) film or polyethylene film is required to impart heat sealability. By selecting and laminating these films by a dry laminating method, a packaging material suitable for heat treatment can be obtained.

  In particular, for retort processing, hot water pressure sterilization is performed under the conditions of 105 ° C to 130 ° C, pressure of 0.1 to 0.3 MPa, and processing time of 10 to 60 minutes. / CPP, PET / ONY / Al / CPP, PET / deposition layer / ONY / CPP are generally mentioned.

  On the other hand, Patent Document 1 devises the development of a PBT / Al / CPP retort packaging material by using polybutylene terephthalate (PBT). Moreover, in order to improve the gas barrier property after a retort process, the polymer containing the high hydrogen bond group with high hydrophilic property in a molecule | numerator represented by poly (meth) acrylic acid and polyvinyl alcohol is used. In addition, the gas barrier properties such as oxygen are excellent under dry conditions, while the gas barrier properties such as oxygen are greatly reduced due to the hydrophilicity under high humidity conditions. There was a problem of poor resistance to.

  In order to solve these problems, it has been proposed to neutralize the carboxy group of a polycarboxylic acid polymer with a polyvalent metal ion.

  For example, in Patent Document 2, a polycarboxylic acid polymer and a polyvalent metal compound are contained in the same or adjacent layers, and a precursor film having a peak ratio at a specific wavelength of an infrared absorption spectrum of less than 0.25 is relative. There is disclosed a film obtained by placing in an atmosphere with a humidity of 20% or more to form a polyvalent metal salt of a polycarboxylic acid polymer to obtain the peak ratio of 0.25 or more.

  Patent Document 3 includes a polymer having a functional group selected from a carboxy group and a carboxylic acid anhydride, wherein at least a part of the —COO— group of the functional group is neutralized with a polyvalent metal ion; A gas barrier laminate having a layer containing a hydrolysis condensate of a compound containing a metal atom to which at least one characteristic group selected from a halogen atom and an alkoxy group is bonded is disclosed.

JP 2012-214248 A International Publication No. 03/091317 International Publication No. 05/053954

  In general, both PET film and ONY film are used in combination as a packaging material composition for heat treatment, particularly retort treatment. This is because PET film has high advantages in hot water resistance, but has the disadvantage of low piercing strength, while ONY film has high strength in piercing strength, while it has low strength in hot water, so it has both advantages and disadvantages. Is used to complement. However, since both PET and ONY are used, the number of laminating processes increases, and there is concern about the impact on the environmental load, and improvements have been demanded from the cost aspect.

  The present invention has been made in view of the above circumstances, and is a gas barrier laminate that has high hot water resistance and puncture strength, and can maintain excellent gas barrier properties even when performing retort processing, boil processing, heat cooking, and the like. Is to provide.

In the first aspect of the present invention, an adhesive layer, a polycarboxylic acid polymer, a general formula R ¹ Si (OR ² ) ₃ (provided that R ^{1 is formed} on one surface of a film substrate made of a biaxially stretched polybutylene terephthalate film Is an organic group containing a glycidyloxy group or an amino group, R ² is an alkyl group, and three R ^{2 s} may be the same or different. At least one silicon-containing compound selected from the group consisting of hydrolysates and condensates thereof in a mass ratio of 99.5: 0.5 to 80.0: 20.0 (provided that the silicon-containing compound mass contains at the silane coupling agent is a mass conversion), and a first gas barrier layer containing no plasticizer, and a second gas barrier layer containing a polyvalent metal compound, Oh heat-sealable Sequentially and a sealant layer, a first gas barrier layer, a second gas barrier layer, the adhesion layer and the gas barrier layered product that does not include a film other than the adhesive layer between the film substrate and the sealant layer, 105 to Oxygen permeability at a temperature of 30 ° C. and a relative humidity of 70% RH after being sterilized by hot water under conditions of 140 ° C. and 0.15 to 0.30 MPa for 10 to 120 minutes is 50 cc / m ² · day · MPa or less This is a gas barrier laminate for pouches.

2nd this invention is a gas barrier laminated body for pouches in which the gas barrier laminated body for pouches of Claim 1 is equipped with the adhesive bond layer between the 2nd gas barrier layer and the sealant layer.

According to a third aspect of the present invention, there is provided the gas barrier laminate for pouches, wherein the gas barrier laminate for pouches according to claim 1 or 2 is used as a packaging material for retort that is sterilized by heating at a pressure of at least 0.15 MPa and a temperature of 110 ° C or higher. Is the body.

The gas barrier laminate according to the present invention has high hot water resistance and puncture strength, and enables a gas barrier laminate capable of maintaining excellent gas barrier properties even when retort treatment, boil treatment, heat cooking, and the like are performed.

It is the schematic diagram which showed the uniform state of the gas barrier laminated body which concerns on this invention. It is the schematic diagram which showed another one aspect | mode of the gas barrier laminated body which concerns on this invention.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings.

  As shown in FIG. 1, the gas barrier laminated body 5 which concerns on embodiment of this invention is the adhesion layer 2, the 1st gas barrier layer (A) 3, and the 2nd gas barrier layer (B) on the film base material 1. As shown in FIG. 4 is a laminate in which 4 are sequentially laminated.

  The film substrate 1 used in the present invention is a biaxially stretched PBT film. The PBT film is manufactured by unmolded PBT film or uniaxially stretched PBT film by cast molding, and is excellent in heat resistance, moldability, and fragrance retention, and is used for food packaging and building materials. . However, these unstretched and uniaxially stretched PBT films have problems in strength and dimensional stability and thus have limited applications, and are not suitable as packaging materials for cooking such as retort processing and boil processing. A biaxially stretched PBT film has higher strength than an unstretched and uniaxially stretched PBT film, and is excellent in impact resistance, heat resistance, and water resistance, and therefore can be used for retort treatment and boil treatment.

  The thickness of the film substrate is not particularly limited. Depending on the application, those of about 6 μm to 200 μm can be used.

  In addition, the film base may be provided with a coating layer such as various pretreatments such as corona treatment, plasma treatment, and frame treatment, and an easy-adhesion layer as long as the barrier performance is not impaired.

  The adhesion layer 2 of the present invention is provided on a base film made of a transparent plastic material, and improves the adhesion performance between the film base 1 and the first gas barrier layer (A) 3 and smoothes the flat surface. The first gas barrier layer (A) in the process is a layer that uniformly forms a film without any defects and exhibits a high barrier property, and is a layer containing an anchor coating agent.

  Examples of such anchor coating agents include polyester-based polyurethane resins and polyether-based polyurethane resins. Among these anchor coating agents, polyester polyurethane resins are preferable from the viewpoints of heat resistance and interlayer adhesion strength.

  Further, the thickness of the adhesion layer 2 is not particularly limited, but the thickness is preferably in the range of 0.01 to 5 μm, more preferably in the range of 0.03 to 3 μm, and 0.05 A range of ˜2 μm is particularly preferable. If the thickness of the adhesion layer is less than the lower limit, the interlayer adhesion strength tends to be insufficient, while if it exceeds the upper limit, the desired gas barrier property tends not to be developed.

  In addition, as a method of coating the anchor coating agent on the polymer film substrate, a known coating method can be used without any particular limitation, and an immersion method (dipping method); spray, coater, printing machine, brush And the like. In addition, the types of coaters and printing presses used in these methods and their coating methods include gravure coaters such as direct gravure, reverse gravure, kiss reverse gravure, and offset gravure, reverse roll coater, and micro gravure. A coater, a coater with chamber doctor, an air knife coater, a dip coater, a bar coater, a comma coater, a die coater and the like can be mentioned.

Further, the coating amount of such an anchor coat agent is preferably mass per 1 m ² after drying by coating an anchor coating agent is 0.01-5 g / ^{m 2,} 0.03 to More preferably, it is 3 g / m ² . If the mass per 1 m ² after coating and drying the anchor coating agent is less than the lower limit, film formation tends to be insufficient. On the other hand, if the upper limit is exceeded, drying is insufficient and the solvent remains. It tends to be easier.

  Further, the method for drying such an anchor coating agent is not particularly limited, but a method by natural drying, a method for drying in an oven set at a predetermined temperature, a dryer attached to the coater, for example, an arch dryer, Examples thereof include a method using a floating dryer, a drum dryer, an infrared dryer and the like. Furthermore, the drying conditions can be appropriately selected depending on the drying method. For example, in the method of drying in an oven, it is preferable to dry at a temperature of 60 to 100 ° C. for about 1 second to 2 minutes.

  The gas barrier layer includes the following first gas barrier layer (A) 3 and a second gas barrier layer (B) 4 containing a polyvalent metal compound.

First gas barrier layer (A) 3: polycarboxylic acid polymer polycarboxylic acid polymer (hereinafter referred to as “polycarboxylic acid polymer (A1) component”), and general formula R ¹ Si (OR ² ) ₃ (wherein R ¹ is an organic group containing a glycidyloxy group or an amino group, R ² is an alkyl group, and three R ^{2 s} may be the same or different). At least one silicon-containing compound selected from the group consisting of a silane coupling agent, a hydrolyzate thereof and a condensate thereof (hereinafter referred to as “silicon-containing compound A2” component), 99.5: 0.5 In the first gas barrier layer (A) containing a mass ratio of ˜80.0: 20.0 (however, the mass of the silicon-containing compound (A2) component is the mass in terms of the silane coupling agent)) is there.

First gas barrier layer (A)
The polycarboxylic acid polymer as the component of the polycarboxylic acid polymer (A1) is a polymer having two or more carboxy groups in the molecule.

  Examples of the component of the polycarboxylic acid polymer (A1) include (co) polymers of ethylenically unsaturated carboxylic acids; copolymers of ethylenically unsaturated carboxylic acids and other ethylenically unsaturated monomers; alginic acid , Acidic polysaccharides having a carboxyl group in the molecule such as carboxymethylcellulose and pectin. Examples of the ethylenically unsaturated carboxylic acid include acrylic acid, methacrylic acid, itaconic acid, maleic acid, fumaric acid, and crotonic acid. Examples of the ethylenically unsaturated monomer copolymerizable with the ethylenically unsaturated carboxylic acid include saturated carboxylic acid vinyl esters such as ethylene, propylene, and vinyl acetate, vinyl chloride, vinylidene chloride, styrene, acrylamide, acrylonitrile, and the like. Is mentioned. These polycarboxylic acid polymers may be used alone or in combination of two or more.

Among the above, the polycarboxylic acid polymer (A1) component is at least selected from the group consisting of acrylic acid, methacrylic acid, itaconic acid, maleic acid, fumaric acid, and crotonic acid from the viewpoint of gas barrier properties obtained. A polymer containing a structural unit derived from one type of polymerizable monomer is preferred, and is derived from at least one type of polymerizable monomer selected from the group consisting of acrylic acid, maleic acid, methacrylic acid and itaconic acid. A polymer containing a structural unit is particularly preferred.

  In the polymer, the proportion of structural units derived from at least one polymerizable monomer selected from the group consisting of acrylic acid, maleic acid, methacrylic acid and itaconic acid is preferably 80 mol% or more. 90 mol% or more is more preferable (however, the total of all the structural units constituting the polymer is 100 mol%). The polymer may be a homopolymer or a copolymer. Examples of constituents other than the above constituent units of the polymer include constituent units derived from an ethylenically unsaturated monomer copolymerizable with the aforementioned ethylenically unsaturated carboxylic acid.

  The number average molecular weight of the polycarboxylic acid polymer (A1) component is preferably in the range of 2,000 to 10,000,000, more preferably 5,000 to 1,000,000. When the number average molecular weight is less than 2,000, the obtained gas barrier layer cannot achieve sufficient water resistance, and the gas barrier property and transparency may be deteriorated by moisture, or whitening may occur. On the other hand, when the number average molecular weight exceeds 10,000,000, before the first gas barrier layer (A) is formed by coating, the viscosity increases and the coating property may be impaired.

  In the polycarboxylic acid polymer (A1) component, a part of the carboxy group may be previously neutralized with a basic compound. Water resistance and heat resistance can be further improved by neutralizing a part of the carboxy group of the polycarboxylic acid polymer (A1) component in advance. The basic compound is preferably at least one basic compound selected from the group consisting of polyvalent metal compounds, monovalent metal compounds and ammonia. Examples of the polyvalent metal compound include the same polyvalent metal compounds as those described in the description of the second gas barrier layer (B). Examples of the basic compound that is a polyvalent metal compound include zinc oxide, calcium carbonate, Sodium carbonate etc. are mentioned. Examples of the basic compound that is a monovalent metal compound include sodium hydroxide and potassium hydroxide. As the degree of neutralization of carboxy groups, the first gas barrier layer (A) is composed of a first coating liquid (a) containing a polycarboxylic acid polymer (A1) component and the silicon-containing compound (A2) component. In the case where the coating film is formed by drying, it is preferably 30 mol% or less, and preferably 25 mol% or less from the viewpoint of the coating property and coating solution stability of the first coating solution (a). More preferred. As the polycarboxylic acid polymer (A1) component, one kind may be used alone, or two or more kinds may be mixed and used.

The silicon-containing compound (A2) component has a general formula R ¹ Si (OR ² ) ₃ (where R ¹ is an organic group containing a glycidyloxy group or an amino group, R ² is an alkyl group, R ² may be the same or different from each other) and is at least one silicon-containing compound selected from the group consisting of a hydrolyzate and a condensate thereof. The silicon-containing compound (A2) component improves the adhesion between the adhesion layer 2 and the first gas barrier layer (A) even in a small amount, and improves heat resistance, water resistance, and the like.

In the general formula, examples of the organic group in R ¹ include a glycidyloxyalkyl group and an aminoalkyl group. As the alkyl group for R ² , an alkyl group having 1 to 6 carbon atoms is preferable, and a methyl group or an ethyl group is particularly preferable. Specific examples of the silane coupling agent include γ-glycidoxypropyltrimethoxysilane, γ-glycidoxypropyltriethoxysilane, γ-aminopropyltrimethoxysilane, γ-aminopropyltriethoxysilane, and the like. . Among these, γ-glycidoxypropyltrimethoxysilane and γ-aminopropyltrimethoxysilane are preferable.

The silicon-containing compound (A2) component may be the silane coupling agent itself, a hydrolyzate obtained by hydrolysis of the silane coupling agent, or a condensate thereof. Examples of the hydrolyzate include those in which at least one of the three OR ^{2 in} the general formula is OH. Examples of the condensate include those in which Si—OH of at least two molecules of hydrolyzate is condensed to form a Si—O—Si bond. Hereinafter, a product obtained by condensing a hydrolyzate of a silane coupling agent may be referred to as a hydrolyzed condensate.

  As said silicon-containing compound (A2) component, what performed the hydrolysis and condensation reaction of the silane coupling agent (1) using the sol-gel method can be used. Usually, the silane coupling agent (1) can be easily hydrolyzed, and can easily undergo a condensation reaction in the presence of an acid or alkali. Therefore, only the silane coupling agent (1), only its hydrolyzate, or those It is rare to exist only in the condensate. That is, the silicon-containing compound (A2) component usually contains a silane coupling agent (1), a hydrolyzate thereof, and a condensate thereof. The hydrolyzate includes a partial hydrolyzate and a complete hydrolyzate.

  The silicon-containing compound (A2) component preferably contains at least a hydrolysis condensate. As a method for producing the hydrolysis-condensation product, the silane coupling agent (1) may be directly mixed with a liquid containing the above-mentioned polycarboxylic acid polymer (A1) component and water. Hydrolysis and subsequent condensation reaction may be performed by adding water to obtain a hydrolysis condensate before mixing with the polycarboxylic acid polymer.

  The first gas barrier layer (A) comprises a polycarboxylic acid polymer (A1) component and the silicon-containing compound (A2) component in a mass ratio of 99.5: 0.5 to 80.0: 20.0. Contains. However, the mass of the silicon-containing compound (A2) component is the mass in terms of the silane coupling agent (1).

  That is, as described above, the silicon-containing compound (A2) component usually contains a silane coupling agent, a hydrolyzate thereof, and a condensate thereof, but the mass of the silicon-containing compound (A2) component is the same as that of the silane. It is a value converted to a coupling agent, that is, a charged amount of a silane coupling agent. Within the above range, a gas barrier laminate excellent in abuse resistance can be obtained. Further, the adhesiveness with the adhesive layer 2 is excellent, and delamination hardly occurs. Moreover, the 1st gas barrier layer (A) can be made into a uniform layer without phase separation by containing the said silicon-containing compound (A2) component in the said range.

Further, the presence of the silicon-containing compound (A2) component makes the gas barrier layer of the present invention resistant to acids. When a silane coupling agent in which R ¹ is an organic group containing a glycidyloxy group (γ-glycidoxypropyltrimethoxysilane or γ-glycidoxypropyltriethoxysilane) is used, a polycarboxylic acid The mass ratio of the system polymer (A1) component to the silicon-containing compound (A2) component is preferably 99.5: 0.5 to 90.0: 10.0, and 99.0: 1.0 It is particularly preferred that it is ˜95.0: 5.0. When the silane coupling agent used is ^{one in} which R ¹ is an organic group containing an amino group (γ-aminopropyltrimethoxysilane or γ-aminopropyltriethoxysilane), a polycarboxylic acid polymer ( The mass ratio of the A1) component to the silicon-containing compound (A2) component is preferably 99.0: 1.0 to 80.0: 20.0, and 95.0: 5.0 to 80.0. : 20.0 is particularly preferable.

  Various additives may be contained in the first gas barrier layer (A). Examples of the additive include a plasticizer, a resin, a dispersant, a surfactant, a softener, a stabilizer, an antiblocking agent, a film forming agent, an adhesive, and an oxygen absorber. For example, the plasticizer can be appropriately selected from known plasticizers. Specific examples of the plasticizer include, for example, ethylene glycol, trimethylene glycol, propylene glycol, tetramethylene glycol, 1,3-butanediol, 2,3-butanediol, pentamethylene glycol, hexamethylene glycol, diethylene glycol, Examples thereof include triethylene glycol, polyethylene glycol, polyvinyl alcohol, ethylene-vinyl alcohol copolymer, polyethylene oxide, sorbitol, mannitol, dulcitol, erythritol, glycerin, lactic acid, fatty acid, starch, and phthalic acid ester. These may be used in a mixture as required.

  Among these, polyethylene glycol, polyvinyl alcohol, ethylene-vinyl alcohol copolymer, glycerin, and starch are preferable from the viewpoints of stretchability and gas barrier properties. When such a plasticizer is contained, abuse resistance can be further improved. When an additive includes a compound having two or more hydroxyl groups such as polyvinyl alcohol, the hydroxyl group of the compound and a part of the carboxy group of the polycarboxylic acid polymer (A1) component form an ester bond. Also good. When the first gas barrier layer (A) contains an additive, the mass ratio of the polycarboxylic acid polymer (A1) component to the additive (polycarboxylic acid polymer (A1) component: addition) The agent is usually in the range of 70:30 to 99.9: 0.1, preferably 80:20 to 98: 2.

  From the viewpoint of gas barrier properties, the thickness of the first gas barrier layer (A) is preferably in the range of 0.01 to 5 μm, more preferably in the range of 0.02 to 3 μm, and even more preferably 0.04. It is in the range of ˜1.2 μm. Even when the coating layer includes a plurality of first gas barrier layers (A), the total preferred thickness of the first gas barrier layer (A) in the coating layer is the same as described above.

(Method for forming first gas barrier layer (A))
The first gas barrier layer (A) can usually be formed by a coating method. Specifically, it can be formed by drying a coating film composed of the first coating liquid (a) containing the polycarboxylic acid polymer (A1) component and the silicon-containing compound (A2) component. As the polycarboxylic acid polymer (A1) component and the silicon-containing compound (A2) component contained in the first coating liquid (a), the same ones as described above can be used.

  The first coating liquid (a) comprises a polycarboxylic acid polymer (A1) component and the silicon-containing compound (A2) component in a mass of 99.5: 0.5 to 80.0: 20.0. Ratio (however, the mass of the silicon-containing compound (A2) component is the mass in terms of the silane coupling agent). The preferred reason is the same as described above.

When a silane coupling agent in which R ¹ is an organic group containing a glycidyloxy group (γ-glycidoxypropyltrimethoxysilane or γ-glycidoxypropyltriethoxysilane) is used, a polycarboxylic acid The mass ratio of the system polymer (A1) component to the silicon-containing compound (A2) component is preferably 99.5: 0.5 to 90.0: 10.0, and 99.0: 1.0 to 95.0: 5.0 is particularly preferred.

As the silane coupling agent, in the case of using those wherein R ¹ is an organic group containing an amino group (.gamma.-aminopropyltrimethoxysilane and, .gamma.-aminopropyltriethoxysilane) is the polycarboxylic acid polymer (A1 ) Component and the silicon-containing compound (A2) component, the mass ratio is preferably 99.0: 1.0 to 80.0: 20.0, and 95.0: 5.0 to 80.0: 20. Is particularly preferred. The mass ratio of the polycarboxylic acid polymer (A1) component and the silicon-containing compound (A2) component usually contained in the first coating liquid (a) and the first coating liquid (a) The mass ratio of the polycarboxylic acid polymer (A1) component and the silicon-containing compound (A2) component in the first gas barrier layer (A) formed using the same is the same. It may be different when the coalescence (A1) component reacts with the additive, or when the polycarboxylic acid polymer (A1) component reacts with the silicon-containing compound (A2) component.

  The first coating liquid (a) can be adjusted by mixing the polycarboxylic acid polymer (A1) component, the silicon-containing compound (A2) component, and additives contained as necessary, with a solvent.

  The solvent used in the first coating liquid (a) is not particularly limited as long as it can dissolve the polycarboxylic acid polymer (A1) component and the silicon-containing compound (A2) component, but usually a silane coupling agent. Since water for performing the hydrolysis reaction is necessary, water, a mixed solvent with water and an organic solvent, and the like are preferable. Water is most preferable in terms of solubility and cost of the polycarboxylic acid polymer (A1) component.

  An organic solvent such as alcohol is preferable in terms of improving the solubility of the silane coupling agent and the coating property of the first coating solution (a). As the organic solvent, it is preferable to use at least one organic solvent selected from the group consisting of alcohols having 1 to 5 carbon atoms and ketones having 3 to 5 carbon atoms. Specific examples of such an organic solvent include methanol, ethanol, propanol, isopropanol, n-butanol, isobutanol, sec-butanol, tert-butanol, acetone, and methyl ethyl ketone. As a mixed solvent of water and an organic solvent, the above-described mixed solvent of water and an organic solvent is preferable, and a mixed solvent of water and an alcohol having 1 to 5 carbon atoms is more preferable. As the mixed solvent, water is present in an amount of 20 to 95% by mass, and an organic solvent is present in an amount of 80 to 5% by mass (provided that the total of water and the organic solvent is 100% by mass). preferable.

  In the first coating liquid (a), from the viewpoint of gas barrier properties and coating properties, the polycarboxylic acid polymer (A1) component and the silicon-containing compound (A2) component in the first coating liquid (a) And, the total content (solid content) of the additives contained as necessary is preferably 0.5 to 50% by mass relative to the total weight of the first coating liquid (a), 0.8 to 30 mass% is more preferable and 1.0-20 mass% is especially preferable.

  The first coating liquid (a) is coated on the surface to be laminated as the first gas barrier layer (A), that is, the adhesion layer 2 to form a coating film, and then the coating film is dried to form the first coating liquid (a). The gas barrier layer (A) can be formed.

  The coating method of the first coating liquid (a) is not particularly limited and can be appropriately selected from known coating methods. For example, casting method, dipping method, roll coating method, gravure coating method, screen printing method, reverse Examples thereof include a coating method, a spray coating method, a kit coating method, a die coating method, a metering bar coating method, a chamber doctor combined use coating method, and a curtain coating method. The coating amount of the first coating liquid (a) is set according to the thickness of the first gas barrier layer (A) to be formed.

  After the first coating liquid (a) is applied, the first gas barrier layer (A) is formed by removing the solvent of the first coating liquid (a) contained in the coating liquid by drying. .

The drying method is not particularly limited, and examples thereof include a hot air drying method, a hot roll contact method, an infrared heating method, and a microwave heating method. These methods may be used alone or in combination of two or more. The first gas barrier layer (A) thus formed contains a polycarboxylic acid polymer (A1) component and a silicon-containing compound (A2) component, and further includes a first coating liquid (a ) Includes other components such as additives, the other components are included. When a compound having two or more hydroxyl groups such as polyvinyl alcohol is used as an additive for the first coating liquid (a), the hydroxyl group of the compound and the polycarboxylic acid system are used during the drying, aging treatment, heat treatment, and the like. A part of the carboxy group of the polymer (A1) component may react to form an ester bond.

Second gas barrier layer (B)
The second gas barrier layer (B) contains a polyvalent metal compound. A polyvalent metal compound is a compound of a polyvalent metal having a metal ion valence of 2 or more. Examples of the polyvalent metal include alkaline earth metals such as beryllium, magnesium, and calcium; transition metals such as titanium, zirconium, chromium, manganese, iron, cobalt, nickel, copper, and zinc; aluminum and silicon. As the polyvalent metal, calcium or zinc is particularly preferable from the viewpoints of heat resistance, water resistance and transparency. As the polyvalent metal compound, a calcium compound or a zinc compound is preferable for the reason described above. Examples of the polyvalent metal compound include a simple substance of polyvalent metal, oxide, hydroxide, carbonate, organic acid salt (for example, acetate) or inorganic acid salt, ammonium complex of polyvalent metal oxide, or 2-4. Secondary amine complexes or their carbonates or organic acid salts. Among these polyvalent metal compounds, from the viewpoint of gas barrier properties, resistance to high-temperature steam and hot water, and productivity, alkaline earth metals, cobalt, nickel, copper, zinc, aluminum or silicon oxides, hydroxides, Preference is given to using chlorides, carbonates or acetates, ammonium complexes of copper or zinc or their carbonates. Among these, zinc oxide, aluminum oxide, calcium hydroxide, calcium carbonate, zinc acetate, and calcium acetate are preferable from the viewpoint of industrial productivity, and zinc oxide or calcium carbonate is particularly preferable.

  When the second gas barrier layer (B) is formed by drying a coating film comprising the second coating liquid (b) containing a polyvalent metal compound, the form of the polyvalent metal compound is particulate. Alternatively, it may be non-particulate or dissolved, but is preferably particulate from the viewpoints of dispersibility, gas barrier properties, and productivity. The average particle size of such particles is not particularly limited, but from the viewpoint of gas barrier properties and coating suitability, the average particle size is preferably 5 μm or less, more preferably 1 μm or less, and 0.1 μm or less. It is particularly preferred that

  If necessary, the second gas barrier layer (B) may contain various additives in addition to the polyvalent metal compound as long as the effects of the present invention are not impaired. As the additive, for example, when the second gas barrier layer (B) is formed by drying a coating film made of the second coating liquid (b) containing a polyvalent metal compound, the second coating is used. Contains a resin soluble or dispersible in the solvent used in the liquid (b), a dispersant soluble or dispersible in the solvent, a surfactant, a softener, a stabilizer, a film forming agent, a thickener, and the like. Also good. Among the above, it is preferable to contain a resin that is soluble or dispersible in the solvent used in the second coating liquid (b). Thereby, the applicability | paintability and film forming property of a 2nd coating liquid (b) improve. Examples of such resins include alkyd resins, melamine resins, acrylic resins, urethane resins, polyester resins, phenol resins, amino resins, fluororesins, epoxy resins, isocyanate resins, and the like.

  Moreover, it is preferable to contain the dispersing agent which is soluble or dispersible in the solvent used for a 2nd coating liquid (b). Thereby, the dispersibility of a polyvalent metal compound improves. As the dispersant, an anionic surfactant or a nonionic surfactant can be used. The surfactant includes (poly) carboxylate, alkyl sulfate ester, alkylbenzene sulfonate, alkyl naphthalene sulfonate, alkyl sulfosuccinate, alkyl diphenyl ether disulfonate, alkyl phosphate, aromatic Phosphate ester, polyoxyethylene alkyl ether, polyoxyethylene alkylphenol ether, polyoxyethylene alkyl ester, alkylallyl sulfate ester salt, polyoxyethylene alkyl phosphate ester, sorbitan alkyl ester, glycerin fatty acid ester, sorbitan fatty acid ester, sucrose fatty acid Ester, polyethylene glycol fatty acid ester, polyoxyethylene sorbitan alkyl ester, polyoxyethylene alkyl allyl ether, polyoxy Styrene derivatives, polyoxyethylene sorbitol fatty acid esters, polyoxy fatty acid esters, various surfactants such as polyoxyethylene alkyl amines. These surfactants may be used alone or in combination of two or more.

  When the second gas barrier layer (B) contains an additive, the mass ratio of the polyvalent metal compound to the additive (polyvalent metal compound: additive) is 30:70 to 99: 1. It is preferable to be within the range, and it is preferable to be within the range of 50:50 to 98: 2.

  From the viewpoint of gas barrier properties, the thickness of the second gas barrier layer (B) is preferably in the range of 0.01 to 5 μm, more preferably in the range of 0.03 to 3 μm, still more preferably 0.1. It is in the range of ˜1.2 μm. Even when the coating layer includes a plurality of second gas barrier layers (B), the total preferred thickness of the second gas barrier layer (B) in the coating layer is the same as described above.

Method for Forming Second Gas Barrier Layer (B) Examples of the method for forming the second gas barrier layer (B) include a coating method and a dipping method. Among these, the coating method is preferable from the viewpoint of productivity. Hereinafter, a case where the second gas barrier layer (B) is formed by a coating method will be described.

  The formation of the second gas barrier layer (B) by the coating method can be specifically performed by drying a coating film composed of the second coating liquid (b) containing a polyvalent metal compound.

  As the polyvalent metal compound contained in the second coating liquid (b), the same compounds as described above can be used, and a calcium compound or a zinc compound is preferable.

  If necessary, the second coating liquid (b) may contain various additives in addition to the polyvalent metal compound as long as the effects of the present invention are not impaired. Examples of the additive include a resin that is soluble or dispersible in the solvent used in the second coating liquid (b), a dispersant that is soluble or dispersible in the solvent, other surfactants, softeners, and stabilizers. Agents, film forming agents, thickeners and the like. Among the above, the second coating liquid (b) can be used as a solvent for the second coating liquid (b) for the purpose of improving the coating property and film forming property of the second coating liquid (b). It is preferable to use a mixture of soluble or dispersible resins. Examples of such a resin include the same resins as those mentioned as various additives that may be contained in the second gas barrier layer (B). In addition, as an additive, for the purpose of improving the dispersibility of the polyvalent metal compound, it is preferable to mix and use a dispersant that is soluble or dispersible in the solvent used in the second coating liquid (b). Examples of the dispersant include those similar to those mentioned above as various additives that the second gas barrier layer (B) may contain. When the second coating liquid (b) contains an additive, the mass ratio of the polyvalent metal compound to the additive (polyvalent metal compound: additive) is 30:70 to 99: 1. It is preferably within the range, and more preferably within the range of 50:50 to 98: 2.

Examples of the solvent used in the second coating liquid (b) include water, methyl alcohol, ethyl alcohol, isopropyl alcohol, n-propyl alcohol, n-butyl alcohol, n-pentyl alcohol, dimethyl sulfoxide, and dimethylformamide. , Dimethylacetamide, toluene, hexane, heptane, cyclohexane, acetone, methyl ethyl ketone, diethyl ether, dioxane, tetrahydrofuran, ethyl acetate, butyl acetate and the like. These solvents may be used alone or in combination of two or more. Among these, methyl alcohol, ethyl alcohol, isopropyl alcohol, toluene, ethyl acetate, methyl ethyl ketone, and water are preferable from the viewpoint of coatability. From the viewpoint of productivity, methyl alcohol, ethyl alcohol, isopropyl alcohol, and water are preferable. In addition, since the 1st gas barrier layer (A) formed from a 1st coating liquid (a) is excellent in water resistance, water can be used as a solvent used for a 2nd coating liquid (b). .

  The second coating liquid (b) is applied on the surface on which the second gas barrier layer (B) is laminated, for example, on the first gas barrier layer (A) to form a coating film. The second gas barrier layer (B) can be formed by drying.

  The coating method of the second coating liquid (b) is not particularly limited and can be appropriately selected from known coating methods. For example, casting method, dipping method, roll coating method, gravure coating method, screen printing method, reverse Examples thereof include a coating method, a spray coating method, a kit coating method, a die coating method, a metering bar coating method, a chamber doctor combined use coating method, and a curtain coating method.

  The coating amount of the second coating liquid (b) is set according to the thickness of the second gas barrier layer (B) to be formed. After the second coating liquid (b) is applied, the second gas barrier layer (B) is formed by removing the solvent of the second coating liquid (b) contained in the coating film by drying.

  The drying method is not particularly limited, and examples thereof include a hot air drying method, a hot roll contact method, an infrared heating method, and a microwave heating method. These methods may be used alone or in combination of two or more. Although there is no limitation in particular as drying temperature, When using the water mentioned above as a solvent, or the mixed solvent of water and an organic solvent, 50 to 160 degreeC is preferable normally. Further, the pressure during drying is usually normal pressure or reduced pressure, and it is preferably normal pressure from the viewpoint of facility simplicity. When the second gas barrier layer (B) thus formed contains a polyvalent metal compound, and the second coating liquid (b) further contains other components such as additives. , Applicable other ingredients are included.

  Moreover, the gas barrier laminated body which can be set as a packaging material with more practical use can be provided by providing a sea continuous and a layer on said 2nd gas barrier layer. The sealant layer is used for an adhesive portion when forming a bag-like package body, for example, polyethylene, polypropylene, ethylene-vinyl acetate copolymer, ethylene-methacrylic acid copolymer, ethylene-methacrylic acid. Resins such as ester copolymers, ethylene-acrylic acid copolymers, ethylene-acrylic acid ester copolymers, and metal cross-linked products thereof are used.

  The thickness is determined according to the purpose, but is generally in the range of 15 to 200 μm. Moreover, it may be the structure which provides a sealant layer in the base material side according to the shape of a package, and the structure provided in both sides.

  As a method for forming the sealant layer, a dry lamination method in which a film made of the above-described resin is bonded with a one-component curable type or two-component curable urethane adhesive, a non-solvent in which a non-solvent is bonded using a solventless adhesive The dry laminating method, the extrusion laminating method in which the above-mentioned resin is heated and melted, extruded into a curtain shape, and bonded together can be formed by any known laminating method. The dry laminating method is preferable for the high-temperature hot water treatment. Any treatment at a temperature of 85 ° C. or lower can be used regardless of the laminating method.

Examples of the heat sterilization treatment method include retort treatment and boil treatment. In general, retort treatment is a method of sterilizing microorganisms such as molds, yeasts, and bacteria in order to preserve foods and the like. Usually, the gas barrier laminate packaging material in which food is packaged is subjected to pressure sterilization at 105 to 140 ° C. and 0.15 to 0.30 MPa for 10 to 120 minutes.

  There are two types of retort devices, a steam type using heated steam and a hot water type using pressurized heated water, which are properly used depending on the sterilization conditions of food or the like as the contents. The boil treatment is a method of sterilizing with heat and humidity in order to preserve food and the like.

  Usually, although it depends on the contents, a wet heat sterilization treatment is performed on a gas barrier laminate packaging material, such as food, under conditions of 60 to 100 ° C. and atmospheric pressure for 10 to 120 minutes. The boil treatment is usually carried out using a hot water tank, but there are a batch type which is immersed in a hot water tank at a constant temperature and taken out after a predetermined time, and a continuous type where the hot water tank is sterilized through a tunnel type.

The transparent gas barrier laminate 5 of the present invention preferably has an oxygen permeability at a temperature of 30 ° C. and a relative humidity of 70% RH of 50 cc / m ² · day · MPa or less, more preferably 30 cc / m ² · day · MPa or less. It is. The lower the oxygen permeability, the better. The lower limit is not particularly limited, but is usually 0.1 cc / m ² · day · MPa or more.

  The transparent gas barrier laminate of the present invention has excellent gas barrier properties even when stress (abuse) such as stretching or bending is applied before the heat sterilization treatment is performed. For example, even after the abuse resistance was evaluated under the conditions described in the following (Examples), the oxygen permeability at a temperature of 30 ° C. and a relative humidity of 70% has almost the same oxygen permeability as described above.

  Furthermore, as another embodiment, the adhesion layer 12, the first gas barrier layer (A) 13, the second gas barrier layer (B) 14 are provided on the film substrate 11 as described above, and the adhesive layer 15 is further provided. The gas barrier laminated body 17 which provided the sealant layer 16 through or without can be shown.

  Specific examples of the present invention will be described below.

  The adhesion layer was prepared by the following procedure.

Coating liquid 1: Adhesive solution manufactured by Mitsui Chemicals Co., Ltd. Main agent: Takelac A-525 (inner urethane resin precursor 50% by mass, ethyl acetate 50% by mass) / Curing agent: Takenate A-52 (inner urethane resin curing) Agent: 55% by mass, ethyl acetate: 45% by mass) / solvent: ethyl acetate This was blended at A-525: A-52: ethyl acetate = 9: 1: 165 (solid content concentration 3% by mass).

  The first coating liquid (a) was prepared by the following procedure.

Coating liquid 2: PAA (polyacrylic acid) aqueous solution having a number average molecular weight of 200,000 (Aron A-10H manufactured by Toagosei Co., Ltd., solid content concentration 25% by mass) / GPTMS (γ-glycidoxypropyltrimethoxysilane) / solvent: Water, isopropyl alcohol (IPA)
This was blended with Aron A-10H: GPTMS: water: IPA = 10: 0.17: 66: 7 (solid content concentration 15% by mass).

  GPTMS (γ-glycidoxypropyltrimethoxysilane) manufactured by Shin-Etsu Chemical Co., Ltd. was used.

  The second coating liquid (b) was adjusted by the following procedure.

Coating liquid 3: Zinc oxide-containing resin composition: K035A (Sumitomo Osaka Cement, zinc oxide 16.6% by mass, urethane resin precursor 1.74% by mass, dispersant 1.66% by mass, toluene 72% by mass, methyl ethyl ketone 8 mass%) / curing agent: C-320 (including urethane resin curing agent 75 mass%, ethyl acetate 25 mass%) / solvent: toluene, methyl ethyl ketone (MEK), IPA
This was blended at K035A: C-320: toluene: MEK: IPA = 100: 3: 24: 3: 3 (solid content concentration 15% by mass).

Example 1
Using the gravure coat on the corona-treated side of the biaxially stretched polybutylene terephthalate film (PBT, thickness 15 μm) that is a film substrate, the above 1 to 3 coating solutions are sequentially applied to form an adhesion layer (0.1 g / m ² ) A transparent gas barrier laminate composed of PAA (0.4 g / m ² ) / ZnO (as ZnO, 0.4 g / m ² ) was obtained.

(Experimental example 1)
On the ZnO layer of the gas barrier laminate of Example 1, an unstretched polypropylene film (CPP: Trefan NO ZK207 manufactured by Toray Film Processing Co., Ltd., thickness 70 μm) is used as a two-component adhesive (Mitsui Chemicals A525 / A52). Then, a laminate film having a configuration of [transparent gas barrier laminate / adhesive layer / CPP (70 μm)] was obtained by dry lamination.

  Next, the obtained laminate film was three-way impulse sealed in a 15 cm × 10 cm pouch shape, 200 ml of tap water was put into the contents, and the remaining one side was impulse-sealed to prepare a four-way pouch. This pouch was retorted at 0.2 MPa and 121 ° C. for 30 minutes using a retort apparatus.

(Experimental example 2)
On the ZnO layer of the gas barrier laminate of Example 1, a linear low-density polyethylene film (LLDPE: TUX-MC-S, manufactured by Mitsui Chemicals, Inc., cello, thickness 60 μm) is used with the same adhesive as in Experimental Example 1. Lamination was performed by a dry laminating method to obtain a laminate film having a configuration of [transparent gas barrier laminate / adhesive layer / CPP (70 μm)].

  Next, the obtained laminate film was three-way impulse sealed in a 15 cm × 10 cm pouch shape, 200 ml of tap water was put into the contents, and the remaining one side was impulse-sealed to prepare a four-way pouch. This pouch was boiled at 90 ° C. for 30 minutes with a boil apparatus.

(Comparative Example 1)
Using a gravure coat on the corona-treated side of a biaxially stretched polyethylene terephthalate film (PET, thickness 12 μm) that is a film substrate, coating solutions 1 to 3 are applied in the same manner as in Example 1 to obtain a transparent gas barrier laminate. Obtained. Then, it laminated using the adhesive agent similarly to Experimental example 1, and obtained what was similarly retort-treated.

(Comparative Example 2)
Using a gravure coat on the corona-treated side of a biaxially stretched polyethylene terephthalate film (PET, thickness 12 μm) that is a film substrate, coating solutions 1 to 3 are applied in the same manner as in Example 1 to obtain a transparent gas barrier laminate. Obtained. Next, on the ZnO layer of the transparent gas barrier laminate, a biaxially stretched nylon film (ONY: ONIC, ONBC thickness 15 μm) is dry-laminated using a two-component adhesive (Mitsui Chemicals A525 / A52). Laminate, and then laminate the unstretched polypropylene film (CPP: Toray film processed Trefan NO ZK207, thickness 70μm) on the ONY by dry laminating method using a two-component adhesive (Mitsui Chemicals A525 / A52) Then, a laminate film having a configuration of [transparent gas barrier laminate / adhesive layer / ONY (15 μm) / adhesive layer / CPP (70 μm)] was obtained. Then, what carried out the retort process similarly to Experimental example 1 was obtained.

(Comparative Example 3)
Using a gravure coat on the corona-treated side of a biaxially stretched polyethylene terephthalate film (PET, thickness 12 μm) that is a film substrate, coating solutions 1 to 3 are applied in the same manner as in Example 1 to obtain a transparent gas barrier laminate. Obtained. Next, it laminated on the ZnO layer of the transparent gas barrier laminated body with the LLDPE film similarly to Experimental example 2. Further, a four-way pouch was prepared in the same manner as in Experimental Example 2 and then boiled at 90 ° C. for 30 minutes.

  The pouch evaluation after the hot water heat treatment is described below. In addition, after hot water heat processing, the content tap water was thrown away and it evaluated in the state dried sufficiently.

<1> Gas barrier property evaluation: [Measurement method of oxygen permeability]
Using an oxygen permeability measuring device (OXTRAN 2/20 manufactured by Modern Control), measurement was performed under conditions of a temperature of 30 ° C. and a relative humidity of 70%. The measuring method was based on JIS K-7126 and B method (isobaric method), and the measured value was expressed in the unit [cc / m ² · day · MPa] (N = 3 average value).

  <2> Evaluation of puncture strength: The load when a needle having a diameter of 1 mm is punctured at a speed of 50 mm / min is measured (N = 3 average value).

  <3> Evaluation of pressure-resistant strength: A weight of 80 kg was applied to a pouch containing 200 ml of water and held for 1 minute, and then the number of broken bags was confirmed (N = 5).

  <4> Evaluation of the low temperature drop test: After storing a pouch containing 200 ml of water in an environment of 5 ° C. for 24 hours, immediately check the number of times from free fall from the floor to a floor of 1 m to break the bag. (N = 3, maximum number of drops 50 times).

  As shown in Table 1, the barrier evaluation after the retort treatment was good in Examples 2, 3 and Comparative Examples 1, 2, and 3, and the pressure strength was not a problem. In the two-layer film configuration of the gas barrier laminates and sealant layers of Examples 2 and 3 and Comparative Examples 1 and 3, it was found that the examples of the present invention were better than Comparative Examples 1 and 3 in terms of puncture strength. The puncture strength of the PBT / CPP configuration of Example 2 was comparable to the PET / ONY / CPP configuration of Comparative Example 2.

  It turned out that the PBT base material of a gas barrier laminated body is equipped with the hot water resistance and puncture impact strength equivalent to the combination of conventional PET and ONY.

  Further, in the low temperature drop test evaluation, it was found that the gas barrier laminates and the sealant layers of Examples 2 and 3 and Comparative Examples 1 and 3 were broken by impact more times than the comparative example. Thereby, it was confirmed that Examples 2 and 3 using the gas barrier laminate of Example 1 have high impact strength at low temperatures and Comparative Examples 1 and 3 have weak impact strength.

The gas barrier laminate of the present invention can obtain a sufficient low temperature drop impact strength after hot water heating treatment even if the biaxially stretched PBT film is used as a base material and the layer structure of the packaging material for retort is simplified to two layers. It can be used as a packaging member suitable for boil and retort applications that have excellent barrier properties.

1, 11 Film substrate 2, 12 Adhesion layer 3, 13 First gas barrier layer (A)
4, 14 Second gas barrier layer (B)
15 Adhesive layer 16 Sealant layer 5, 17 Gas barrier laminate

Claims (3)

An adhesive layer, a polycarboxylic acid polymer, and a general formula R ¹ Si (OR ² ) ₃ (wherein R ¹ is a glycidyloxy group or an amino group) on one side of a film substrate made of a biaxially stretched polybutylene terephthalate film R ² is an alkyl group, and three R ^{2 s} may be the same or different from each other), a hydrolyzate thereof, and a condensation thereof. And at least one silicon-containing compound selected from the group consisting of a mass ratio of 99.5: 0.5 to 80.0: 20.0 (wherein the mass of the silicon-containing compound is the silane coupling) agent contained in the mass and is) conversion, and a first gas barrier layer containing no plasticizer, and a second gas barrier layer containing a polyvalent metal compound, and heat-sealing property of certain sealant layer Sequentially comprising, a first gas barrier layer between the film substrate and the sealant layer, the second gas barrier layer, a contact layer and the gas barrier layered product that does not include a film other than the adhesive layer, from 105 to 140 ° C., 0 .For pouches having an oxygen permeability of 50 cc / m ² · day · MPa or less at a temperature of 30 ° C. and a relative humidity of 70% RH after being subjected to hot water pressure sterilization at 15 to 0.30 MPa for 10 to 120 minutes. Gas barrier laminate. The gas barrier laminate for a pouch according to claim 1 , wherein the gas barrier laminate for a pouch comprises an adhesive layer between the second gas barrier layer and the sealant layer. A gas barrier laminate for a pouch as a packaging material for a retort, wherein the gas barrier laminate for a pouch according to claim 1 or 2 is heat sterilized at a pressure of at least 0.15 MPa and a temperature of 110 ° C or higher.

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