JP7010023B2 - Gas barrier film - Google Patents

Description

The present invention relates to a gas barrier film used for a package.

Packaging of foods, pharmaceuticals, etc. is highly airtight, and packaging materials using various plastic films, metal foils, papers, and other materials have been developed in order to prevent deterioration of the contents due to moisture and oxygen. In particular, as a packaging form that can be stored for a long period of time in food / pharmaceutical applications, retort packaging and boil packaging that have been heat-sterilized such as retort and boil are generally used. Characteristics required for packaging materials for retort and boiling include various gas barrier properties, heat-resistant water-resistant properties, aroma retention properties, discoloration resistance, impact resistance, pressure resistance, piercing resistance, bending resistance, etc., and heat treatment conditions and contents. A laminate configuration suitable for the object is designed.

As an example of such a packaging material, for example, in order to impart heat resistance, fragrance retention, printability, etc., a biaxially stretched polyethylene terephthalate (hereinafter referred to as PET) film is used as a base material to impart impact resistance and piercing resistance. A biaxially stretched nylon (hereinafter referred to as ONY) film, an aluminum (Al) foil as a gas barrier layer for imparting barrier properties, or a vapor-deposited film is laminated to prepare a gas barrier film.

Further, in order to impart heat-sealing properties, a heat-resistant grade unstretched polypropylene (hereinafter referred to as CPP) film, a polyethylene film, or the like is used as a sealant and bonded to the gas barrier film coated with an adhesive by a dry laminating method to form a gas barrier laminate. By doing so, a packaging material suitable for heat treatment can be obtained.

Retort treatment is a method of pressurizing and sterilizing microorganisms such as molds, yeasts, and bacteria in order to store foods and the like. Usually, the gas barrier laminate packaging material in which food is packaged is subjected to pressure sterilization treatment at 105 to 140 ° C. and 0.15 to 0.30 MPa under the conditions of 10 to 120 minutes. There are two types of retort pouches, a steam type that uses heated steam and a hot water type that uses pressurized heated water, and they are used appropriately according to the sterilization conditions of the food or the like to be the contents.

Boil treatment is a method of moist heat sterilization for preserving foods and the like. Usually, although it depends on the contents, the gas barrier laminated body packaging material in which food or the like is packaged is subjected to moist heat sterilization treatment under the conditions of 60 to 100 ° C. and atmospheric pressure for 10 to 120 minutes. The boiling treatment is usually carried out at 100 ° C. or lower using a hot water tank. As a method, there are a batch type in which the material is immersed in a hot water tank at a constant temperature and treated for a certain period of time and then taken out, and a continuous type in which the inside of the hot water tank is passed through a tunnel type for treatment.

For example, as the hot water pressure sterilization treatment for retort treatment, a gas barrier is used for hot water pressure sterilization treatment under the conditions of 105 ° C. to 130 ° C., pressure 0.10 to 0.30 MPa, and treatment time of 10 to 60 minutes. PET / Al / ONY / CPP, PET / ONY / Al / CPP, and PET / thin-film layer / ONY / CPP are used from the outside as the laminated structure of the laminated body packaging material. As described above, the combined use of the PET film and the ONY film is generally performed.

On the other hand, Patent Document 1 proposes the development of a PBT / Al / CPP structure into a retort packaging material by using polybutylene terephthalate (hereinafter referred to as PBT). Further, in order to improve the gas barrier property after the retort treatment, a polymer having a highly hydrophilic high hydrogen-bonding group in the molecule, such as poly (meth) acrylic acid and polyvinyl alcohol, is used. While it has excellent gas barrier properties such as oxygen under dry conditions, it has a problem that the gas barrier properties such as oxygen are greatly reduced due to its hydrophilicity under high humidity conditions, and humidity and hot water. There was a problem of poor resistance to.

In order to solve these problems, it has been proposed to neutralize the carboxy group of the polycarboxylic acid-based polymer with a polyvalent metal ion. For example, Patent Document 2 describes a precursor film containing a polycarboxylic acid-based polymer and a polyvalent metal compound in the same or adjacent layers and having a peak ratio of less than 0.25 at a specific wavelength in the infrared absorption spectrum. A film having a peak ratio of 0.25 or more by forming a polyvalent metal salt of a polycarboxylic acid-based polymer in an atmosphere having a humidity of 20% or more is disclosed.

Patent Document 3 describes a polymer having a functional group selected from a carboxy group and a carboxylic acid anhydride, in which 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.

On the other hand, as a method of imparting gas barrier properties to a base film, a method of providing an inorganic vapor-deposited layer made of an inorganic compound such as a metal oxide is known (see, for example, Patent Document 4).
Further, it has been proposed to provide a primer layer between the base film and the inorganic vapor deposition layer in order to improve the adhesion of the inorganic vapor deposition layer to the base film (see, for example, Patent Document 5).

Further, in order to impart further high barrier property, water resistance and moisture resistance, it has been proposed to provide a gas barrier coating layer on the inorganic thin-film deposition layer. For example, in Patent Document 6, a water-soluble polymer and an aqueous solution or a water-alcohol mixed solution containing I) one or more kinds of metal alkoxides or metal alkoxide hydrolysates, or II) tin chloride are used as main components on an inorganic vapor deposition layer. Described is a method of providing a gas barrier packaging material in which a gas barrier coating layer formed by applying a coating agent to be heated and dried is sequentially laminated as a second layer.

However, in the gas barrier laminated body provided with the inorganic thin-film deposition layer, the adhesion between the layers tends to decrease due to deterioration of the material of the barrier layer such as the inorganic thin-film deposition layer due to the heat treatment, and retort treatment, boiling treatment, cooking, etc. When the heat treatment is performed, delamination of the inorganic thin-film deposition layer may occur, and the gas barrier property may be deteriorated. Further, since the inorganic thin-film deposition layer is made of an inorganic compound, it is fragile, and when stress (abuse) is applied to the gas barrier film by stretching, bending, etc., the inorganic vapor deposition layer is damaged and the gas barrier property tends to deteriorate.

Japanese Unexamined Patent Publication No. 2012-214248 International Publication No. 2003/091317 International Publication No. 2005/053954 Japanese Patent No. 3448872 Japanese Patent No. 3736130 Japanese Patent No. 2790054

As described above, both the PET film and the ONY film are generally used in combination as the packaging material composition for the heat treatment, particularly the retort treatment. This is an advantage of PET film having high heat resistance and a disadvantage of low piercing strength, and an ONY film has an advantage of high piercing strength and a disadvantage of low heat resistance, so that the advantages and disadvantages are complemented with each other. This is for use. However, since both PET and ONY are used, the number of laminating processes increases, and there is a concern about the influence on the environmental load, and improvement is required from the viewpoint of cost.

The present invention has been made in view of the above circumstances, and an object of the present invention is to perform hot water treatment such as retort treatment without using both PET and ONY layers to complement the advantages. It is an object of the present invention to provide a gas barrier film which can maintain excellent gas barrier properties even when carried out and is also excellent in piercing strength and strength against physical impact.

In order to solve the above problems, the first invention according to the present invention is
A vapor-deposited layer made of an inorganic oxide or a metal oxide, a first coating layer, and a second coating layer are formed on one surface of a film substrate containing a polyester resin having a butylene terephthalate unit as a main constituent unit. Are stacked in this order,
The first coating layer is selected from the group consisting of a polycarboxylic acid-based polymer, a silane coupling agent represented by the general formula ^R1Si (OR ² ) ₃ , a hydrolyzate thereof, and a condensate thereof. A layer containing at least one silicon-containing compound in a mass ratio of 99.5: 0.5 to 80.0: 20.0.
The second coating layer is a layer containing a polyvalent metal compound, and is a layer containing a polyvalent metal compound.
The thickness of the film substrate is 12 μm or more.
It is a gas barrier film characterized by this.
(However, R ¹ is an organic group containing a glycidyloxy group or an amino group, R ² is an alkyl group, and the three R ^2s do not have to be the same.)

The second invention is a gas barrier film characterized in that an adhesion layer containing an anchor coating agent is provided between the film base material and the vapor-deposited layer.

The third invention is a gas barrier film characterized in that the inorganic oxide is aluminum oxide or silicon oxide.

The fourth invention is a gas barrier film characterized in that the number average molecular weight of the polycarboxylic acid-based polymer is in the range of 2,000 to 10,000,000.

In the fifth invention, the elongation rate Y (formula 1 below) in the film traveling direction (MD direction) when the gas barrier film is tensioned at 10 N / m to 70 N / m at a temperature of 50 ° C to 150 ° C. , 30% or less, which is a gas barrier film.
Elongation rate Y = ((length of film when tensioned at a predetermined temperature)-(length when tension is not applied at room temperature))) / (length of film when tension is applied at a predetermined temperature) Length) ・ ・ ・ (Formula 1)

In the sixth invention, in the gas barrier film, the elongation rate Y is based on the temperature X (° C.) and the tension Z (N / m) applied to the arbitrary film with respect to the reference value G represented by the following formula 2. It is a gas barrier film characterized in that Y ≦ G.
Reference value G = 0.8 × (temperature applied to film X (° C.) -50) × (0.9 × (tension Z (N / m) -5) / 40) ・ ・ ・ (Formula 2)

The gas barrier film according to the present invention has made it possible to obtain a gas barrier film having high heat resistance and piercing strength and capable of maintaining excellent gas barrier properties even after retort treatment, boiling treatment, cooking and the like.

It is a schematic cross-sectional view which showed the uniformity of the gas barrier film 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 film 10 according to the embodiment of the present invention has an adhesion layer 2, a thin-film deposition layer 3, a first coating layer (A) 4, and a second coating layer (on a film substrate 1). B) 5 is sequentially laminated. In the present invention, the adhesion layer 2 is not an essential configuration, and the adhesion layer 2 can be omitted if the adhesion between the film base material 1 and the vapor-film deposition layer 3 is sufficient.

The first coating layer (A) 4 is a polycarboxylic acid-based polymer and a general formula R ¹ Si (OR ² ) ₃ (where R ¹ is an organic group containing a glycidyloxy group or an amino group, and R ² Is an alkyl group, and the three ^R2s may be the same or different from each other). At least one kind of silicon-containing compound is mixed with a mass ratio of 99.5: 0.5 to 80.0: 20.0 (however, the mass of the silicon-containing compound is the mass in terms of the silane coupling agent). It is a layer containing.
The second coating layer (B) 5 is a layer containing a polyvalent metal compound.

(Film base material)
The film substrate 1 used in the present invention contains a polyester resin containing a butylene terephthalate (PBT) unit as a main constituent unit.
Further, as the film base material 1, a stretched film is used instead of an unstretched film produced by a casting method. The unstretched PBT film has problems in strength and dimensional stability, so its use is limited, and it is not suitable as a packaging material for cooking such as retort treatment and boiling treatment. The stretched PBT film has higher strength than the unstretched PBT film, and is excellent in impact resistance, heat resistance, and water resistance, so that it can be used for retort treatment and boiling treatment. As the stretching method, any method may be used as long as a film having stable dimensions such as a stretched film by inflation or a uniaxially stretched or biaxially stretched PBT film can be supplied.

The thickness of the film substrate 1 can be appropriately selected depending on the intended use, but a film having a thickness of about 12 μm to 200 μm can be used. By setting this thickness to 12 μm or more, the impact resistance is high and the deterioration of the barrier property due to thermal deformation or the like can be prevented.

Further, the film substrate 1 may be subjected to various pretreatments such as corona treatment, plasma treatment, frame treatment, etc., or a coat layer such as an easy-adhesion layer may be provided on the laminated surface as long as the barrier performance is not impaired. ..

(Adhesion layer)
The adhesion layer 2 of the present invention is provided on a base film made of a transparent plastic material, and by improving the adhesion performance between the film base material 1 and the inorganic vapor deposition layer 3 and smoothing the flat surface, the vapor deposition layer in the next step is defective. It is a layer for the purpose of obtaining two effects of uniformly forming a film without forming a film and exhibiting a high barrier property, and is a layer containing an anchor coating agent.

Examples of the anchor coating agent contained in such an adhesion layer 2 include polyester-based polyurethane resin and polyether-based polyurethane resin. Among these anchor coating agents, polyester-based polyurethane resins are preferable from the viewpoint of heat resistance and interlayer adhesion strength.

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. It is particularly preferably in the range of 05 to 2 μm. If the thickness of the adhesion layer 2 is less than the lower limit value, the interlayer adhesive strength tends to be insufficient, while if it exceeds the upper limit value, the desired gas barrier property tends not to be exhibited.

Further, as a method of coating the adhesion layer 2 on the film substrate 1, a known coating method can be used without particular limitation, and a dipping method (dipping method); a spray, a coater, a printing machine, a brush, etc. Is mentioned. The types of coaters and printing machines used in these methods and their coating methods include gravure coaters such as direct gravure method, reverse gravure method, kiss reverse gravure method, and offset gravure method, reverse roll coater, and micro gravure. Examples include coaters, chamber doctor combined coaters, air knife coaters, dip coaters, bar coaters, comma coaters, and die coaters.

Further, as for the coating amount of such an adhesion layer 2, the mass per 1 m ² after the anchor coating agent is applied and dried is preferably 0.01 to 5 g / m ² , preferably 0.03 to 0.03. More preferably, it is 3 g / m ² . If the mass per 1 m ² after applying the anchor coating agent and drying is less than the lower limit, the film formation tends to be insufficient, while if it exceeds the upper limit, the drying is insufficient and the solvent remains. It tends to be easier.

The method for drying the adhesion layer 2 is not particularly limited, but a method by natural drying, a method of drying in an oven set to a predetermined temperature, a dryer attached to the coater, for example, an arch dryer, etc. Examples thereof include a method using a floating dryer, a drum dryer, an infrared dryer and the like. Further, the drying conditions can be appropriately selected depending on the method of drying. 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.

(Embedded layer)
The vapor-filmed layer 3 used in the gas barrier film 10 of the present invention preferably contains at least one of Al and Si. More specifically, a metal oxide represented by SiOx or AlOx, or a mixture thereof can be used, but it may contain a simple substance atom of nitrogen or aluminum.

The film thickness of the thin-film deposition layer 3 is preferably 5 nm or more and 100 nm or less. If the film thickness is less than 5 nm, sufficient water vapor barrier properties cannot be obtained. If it is larger than 100 nm, cracks are generated due to deformation of the thin film due to internal stress, and the water vapor barrier property is lowered. Further, the cost increases due to an increase in the amount of material used, a long film forming time, and the like, which is not preferable from an economical point of view.

At least one of the thin-film deposition layers 3 needs to be formed by vacuum film formation. In the vacuum film formation, for example, a physical vapor deposition method or a chemical vapor deposition method can be used. Examples of the physical vapor deposition method include, but are not limited to, a vacuum vapor deposition method, a sputtering method, and an ion plating method. Examples of the chemical vapor deposition method include, but are not limited to, a thermal CVD method, a plasma CVD method, and an optical CVD method.

In the vacuum film formation, resistance heating type vacuum deposition method, EB (Electron Beam) heating type vacuum deposition method, induction heating type vacuum deposition method, sputtering method, reactive sputtering method, dual magnetron sputtering method, plasma chemical vapor deposition method (PECVD method) and the like are particularly preferably used.

Although plasma is used in the methods after the sputtering method, plasma generation such as DC (Direct Current) method, RF (Radio Frequency) method, MF (Middle Frequency) method, DC pulse method, RF pulse method, DC + RF superimposition method and the like is used. The law can be applied.

In the case of the sputtering method, a negative potential gradient is generated in the target, which is a cathode, and Ar ions receive potential energy and collide with the target. Here, even if plasma is generated, sputtering cannot be performed unless a negative self-bias potential is generated. MW (Micro Wave) plasma is not suitable for sputtering because it does not self-bias. However, in the PECVD method, since the chemical reaction and deposition processes proceed using the gas phase reaction in the plasma, it is possible to form a film without self-bias, and MW plasma can be used.

Next, the coating layer will be described. The coating layer includes the following first coating layer (A) 4 and a second coating layer (B) 5 containing a polyvalent metal compound.

(First coating layer (A))
The first coating layer (A) 4 includes a polycarboxylic acid-based polymer, a polycarboxylic acid-based polymer (hereinafter referred to as “polycarboxylic acid-based polymer (A1) component”), and a general formula ^R1Si (OR). ² ) ₃ (However, R ¹ is an organic group containing a glycidyloxy group or an amino group, R ² is an alkyl group, and the three R ^2s may be the same or different from each other). At least one kind of silicon-containing compound (hereinafter referred to as "silicon-containing compound (A2)" component) selected from the group consisting of the silane coupling agent, its hydrolyzate, and a condensate thereof is (A1). ): (A2) = 99.5: 0.5 to 80.0: 20.0 (however, the mass of the silicon-containing compound component (A2) is the mass in terms of the silane coupling agent). It is the first coating layer (A) contained.

The polycarboxylic acid-based polymer as a component of the polycarboxylic acid-based polymer (A1) is a polymer having two or more carboxy groups in the molecule.

The components of the polycarboxylic acid-based polymer (A1) include, for example, a (co) polymer of an ethylenically unsaturated carboxylic acid; a copolymer of an ethylenically unsaturated carboxylic acid and another ethylenically unsaturated monomer; an alginic acid. , Carboxymethyl cellulose, pectin and the like, and examples thereof include acidic polysaccharides having a carboxyl group in the molecule. 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 and acrylonitrile. Can be mentioned. These polycarboxylic acid-based polymers may be used alone or in combination of two or more.

Among the above, the polycarboxylic acid-based 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 the obtained gas barrier property. Polymers containing structural units derived from one polymerizable monomer are preferred, and are derived from at least one 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 preferable.

In the polymer, the proportion of the structural unit 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 constituent units constituting the polymer is 100 mol%). The polymer may be a homopolymer or a copolymer. Examples of the constituent elements other than the above-mentioned constituent units of the polymer include constituent units derived from the ethylenically unsaturated monomer copolymerizable with the above-mentioned ethylenically unsaturated carboxylic acid.

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

In the polycarboxylic acid-based polymer (A1) component, a part of the carboxy group may be neutralized with a basic compound in advance. By neutralizing a part of the carboxy group of the polycarboxylic acid polymer (A1) component in advance, water resistance and heat resistance can be further improved. As the basic compound, at least one basic compound selected from the group consisting of a polyvalent metal compound, a monovalent metal compound and ammonia is preferable. Examples of the polyvalent metal compound include those similar to the polyvalent metal compound described in the description of the second gas barrier layer (B), and examples of the basic compound as the polyvalent metal compound include zinc oxide and calcium carbonate. Examples include sodium carbonate. Examples of the basic compound which is a monovalent metal compound include sodium hydroxide and potassium hydroxide.

As the degree of neutralization of the carboxy group, the first coating liquid (a) containing the first coating layer (A) containing the polycarboxylic acid-based polymer (A1) component and the silicon-containing compound (A2) component (described later). When the coating film made of) is formed by drying, it is preferably 30 mol% or less, preferably 25 mol% or less, from the viewpoint of coatability and coating stability of the first coating liquid (a). It is more preferable to have. As the polycarboxylic acid-based polymer (A1) component, one type may be used alone, or two or more types may be mixed and used.

The silicon-containing compound (A2) component is 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, and three. ^R2 is at least one silicon-containing compound selected from the group consisting of a silane coupling agent represented by (which may be the same or different), a hydrolyzate thereof, and a condensate thereof. .. The silicon-containing compound (A2) component improves the adhesion between the adhesion layer 2 and the first coating layer (A) 4 even in a small amount, and improves heat resistance, water resistance, and the like.

In the above general formula, examples of the organic group in R ¹ include a glycidyloxyalkyl group and an aminoalkyl group. As the alkyl group of ^R2 , 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 hydrolyzing the silane coupling agent, or a condensate thereof. Examples of the hydrolyzate include those in which at least one of the three OR ^2s in the general formula is OH. Examples of the condensate include those in which at least two molecules of the hydrolyzate Si—OH are condensed to form a Si—O—Si bond. In the following, the condensed product of the hydrolyzate of the silane coupling agent may be referred to as a hydrolyzed condensate.

As the silicon-containing compound (A2) component, a silane coupling agent that has been hydrolyzed and condensed using the sol-gel method can be used. Normally, a silane coupling agent easily hydrolyzes, and a condensation reaction easily occurs in the presence of an acid or an alkali. Therefore, it exists only in the silane coupling agent, its hydrolyzate alone, or its condensate only. It is rare to do. That is, the silicon-containing compound (A2) component usually contains a silane coupling agent, a hydrolyzate thereof, and a condensate thereof. Further, the hydrolyzate includes a partial hydrolyzate and a complete hydrolyzate.

The silicon-containing compound (A2) component preferably contains at least a hydrolyzed condensate. As a method for producing the hydrolyzed condensate, the silane coupling agent may be directly mixed with the liquid containing the polycarboxylic acid polymer (A1) component and water, or water is added to the silane coupling agent. Thereby, a hydrolysis condensate may be obtained before the hydrolysis and the subsequent condensation reaction are carried out and mixed with the polycarboxylic acid-based polymer.

The first coating layer (A) 4 has a ratio (A1: A2) of the polycarboxylic acid-based polymer (A1) component to the silicon-containing compound (A2) component, which is 99.5: 0.5 to 80. It is contained in a mass ratio of 0: 20.0. However, the mass of the silicon-containing compound (A2) component is the mass in terms of the silane coupling agent.

Here, as described above, the silicon-containing compound (A2) component is usually a mixture of a silane coupling agent, a hydrolyzate thereof, and a condensate thereof, but the mass of the silicon-containing compound (A2) component is the above. It is a value converted into a silane coupling agent, that is, the amount of the silane coupling agent charged. Within the above range, a gas barrier laminate having excellent abuse resistance can be obtained.

Further, the presence of the silicon-containing compound (A2) component makes the gas barrier layer of the present invention resistant to acid. When R ¹ is an organic group containing a glycidyloxy group (γ-glycidoxypropyltrimethoxysilane or γ-glycidoxypropyltriethoxysilane) as the silane coupling agent, a polycarboxylic acid is used. 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, preferably 99.0: 1.0. It is particularly preferable that it is ~ 95.0: 5.0.

When a polycarboxylic acid-based polymer (γ-aminopropyltrimethoxysilane or γ-aminopropyltriethoxysilane) in which R ¹ is an organic group containing an amino group is used as the silane coupling agent, a polycarboxylic acid-based 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, preferably 95.0: 5.0 to 80.0. : 20.0 is particularly preferable.

The first coating layer (A) may contain various additives. Examples of the additive include plasticizers, resins, dispersants, surfactants, softeners, stabilizers, anti-blocking agents, film-forming agents, pressure-sensitive adhesives, oxygen absorbers and the like. For example, as the plasticizer, it is possible to appropriately select and use from known plasticizers. Specific examples of the plasticizer include ethylene glycol, trimethylene glycol, propylene glycol, tetramethylene glycol, 1,3-butanediol, 2,3-butanediol, pentamethylene glycol, hexamethylene glycol, and diethylene glycol. Examples thereof include triethylene glycol, polyethylene glycol, polyvinyl alcohol, ethylene-vinyl alcohol copolymer, polyethylene oxide, sorbitol, mannitol, zulcitol, erythritol, glycerin, lactic acid, fatty acid, starch, and phthalate ester. These may be used as a mixture if necessary.

Among these, polyethylene glycol, polyvinyl alcohol, ethylene-vinyl alcohol copolymer, glycerin, and starch are preferable from the viewpoint of stretchability and gas barrier property. When such a plasticizer is contained, the abuse resistance can be further improved. When the additive contains 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. May be good. When the first coating layer (A) contains an additive, the mass ratio of the polycarboxylic acid-based polymer (A1) component to the additive (polycarboxylic acid-based 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.

The thickness of the first coating 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 further preferably in the range of 0.04 from the viewpoint of gas barrier properties. The range is ~ 1.2 μm. Even when the coating layer contains a plurality of the first coating layers (A), the total preferable thickness of the first coating layers (A) in the coating layer is the same as described above.

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

The first coating liquid (a) contains the polycarboxylic acid-based polymer (A1) component and the silicon-containing compound (A2) component in a mass ratio of 99.5: 0.5 to 80.0: 20.0. The 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 R ¹ is an organic group containing a glycidyloxy group (γ-glycidoxypropyltrimethoxysilane or γ-glycidoxypropyltriethoxysilane) as the silane coupling agent, a polycarboxylic acid is used. 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 10. 95.0: 5.0 is particularly preferable.

When a silane coupling agent in which R ¹ is an organic group containing an amino group (γ-aminopropyltrimethoxysilane or γ-aminopropyltriethoxysilane) is used, a polycarboxylic acid-based polymer (A1) is used. The mass ratio of the component) to the silicon-containing compound (A2) component is preferably 99.0: 1.0 to 80.0: 20.0, preferably 95.0: 5.0 to 80.0: 20. It is particularly preferable to be 0.0.

Normally, the mass ratio of the polycarboxylic acid-based polymer (A1) component and the silicon-containing compound (A2) component contained in the first coating liquid (a) and the first coating liquid (a) are used. The mass ratio of the polycarboxylic acid-based polymer (A1) component to the silicon-containing compound (A2) component in the first gas barrier layer (A) formed is the same, but for example, the polycarboxylic acid-based polymer ( It may be different when the A1) component reacts with the additive, or when the polycarboxylic acid-based polymer (A1) component reacts with the silicon-containing compound (A2) component.

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

The solvent used for the first coating liquid (a) is not particularly limited as long as it can dissolve the polycarboxylic acid-based polymer (A1) component and the silicon-containing compound (A2) component, but is usually silane coupling. Since water is required for the hydrolysis reaction of the agent, water, a mixed solvent of 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 coatability of the first coating liquid (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, methyl ethyl ketone and the like. As the mixed solvent of water and the organic solvent, the above-mentioned mixed solvent of water and the organic solvent is preferable, and the mixed solvent of water and 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 (however, 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 property and coatability, the polycarboxylic acid-based polymer (A1) component and the silicon-containing compound (A2) component in the first coating liquid (a). The total content (solid content) of the above and the additives contained as necessary is preferably 0.5 to 50% by mass, preferably 0.8 to 50% by mass, based on the total weight of the first coating liquid (a). 30% by mass is more preferable, and 1.0 to 20% by mass is particularly preferable.

The first coating liquid (a) is applied onto the surface to be laminated as the first gas barrier layer (A), that is, on the adhesion layer 2, to form a coating film, and the coating film is dried to obtain the first coating film. One coating 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, a casting method, a dipping method, a roll coating method, a gravure coating method, a screen printing method, and a reverse method can be selected. Examples 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 coating method, and a curtain coating method. The amount of the first coating liquid (a) applied is set according to the thickness of the first coating layer (A) to be formed.

After applying the first coating liquid (a), the first coating 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. Any of 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-based polymer (A1) component and a silicon-containing compound (A2) component.
Further, when the first coating liquid (a) contains other components such as additives, the other components are contained. 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 groups 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 with each other to form an ester bond.

(Second coating layer (B))
The second coating layer (B) contains a polyvalent metal compound. The polyvalent metal compound is a compound of a polyvalent metal having a metal ion valence of 2 or more. Examples of polyvalent metals 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 multivalent metal, calcium or zinc is particularly preferable from the viewpoint of heat resistance, water resistance and transparency. As the polyvalent metal compound, a calcium compound or a zinc compound is preferable for the above-mentioned reasons.

Examples of the polyvalent metal compound include a simple substance of the polyvalent metal, an oxide, a hydroxide, a carbonate, an organic acid salt (for example, an acetate) or an inorganic acid salt, an ammonium complex of the polyvalent metal oxide, or 2 to 4 Examples thereof include primary amine complexes, or carbonates or organic acid salts thereof. Among these polyvalent metal compounds, alkaline earth metals, cobalt, nickel, copper, zinc, aluminum or silicon oxides, hydroxides, from the viewpoint of gas barrier properties, resistance to high temperature steam and hot water, and manufacturability, It is preferred to use chlorides, carbonates or acetates, ammonium complexes of copper or zinc or carbonates thereof. Among these, zinc oxide, aluminum oxide, calcium hydroxide, calcium carbonate, zinc acetate and calcium acetate are preferable, and zinc oxide or calcium carbonate is particularly preferable, from the viewpoint of industrial productivity.

When the second coating layer (B) is formed by drying a coating film composed of the second coating liquid (b) containing the polyvalent metal compound, the form of the polyvalent metal compound is particulate. However, it may be in the form of non-particulates or may be dissolved, but it is preferably in the form of particles from the viewpoint of dispersibility, gas barrier property 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. Is particularly preferable.

The second coating layer (B) may contain various additives in addition to the polyvalent metal compound, if necessary, as long as the effects of the present invention are not impaired. As the additive, for example, when the second coating layer (B) is formed by drying a coating film composed of the second coating liquid (b) containing a polyvalent metal compound, the second coating is used. It contains a resin that is soluble or dispersible in the solvent used in the liquid (b), a dispersant that is soluble or dispersible in the solvent, a surfactant, a softener, a stabilizer, a film-forming agent, a thickener, and the like. May be good.
Among the above, it is preferable to contain a resin that is soluble or dispersible in the solvent used for the second coating liquid (b). As a result, the coatability and film forming property of the second coating liquid (b) are improved. 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.

Further, it is preferable to contain a dispersant that is soluble or dispersible in the solvent used for the second coating liquid (b). This improves the dispersibility of the polyvalent metal compound. As the dispersant, an anionic surfactant or a nonionic surfactant can be used. Examples of the surfactant include (poly) carboxylate, alkyl sulfate ester salt, alkylbenzene sulfonate, alkylnaphthalene sulfonate, alkylsulfosuccinate, alkyldiphenylether disulfonate, alkylphosphate, and aromatic. Phosphoric acid 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, citrus fatty acid Various surfactants such as esters, polyethylene glycol fatty acid esters, polyoxyethylene sorbitan alkyl esters, polyoxyethylene alkyl allyl ethers, polyoxyethylene derivatives, polyoxyethylene sorbitol fatty acid esters, polyoxy fatty acid esters, polyoxyethylene alkylamines, etc. Be done. These surfactants may be used alone or in combination of two or more.

When the additive is contained in the second coating layer (B), 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, preferably within the range of 50:50 to 98: 2.

The thickness of the second coating layer (B) is preferably in the range of 0.01 to 5 μm, more preferably in the range of 0.03 to 3 μm, and further preferably in the range of 0.1 from the viewpoint of gas barrier properties. The range is ~ 1.2 μm. Even when the coating layer contains a plurality of the second coating layers (B), the total preferable thickness of the second coating layers (B) in the coating layer is the same as described above.

(Method for forming the second coating layer (B))
Examples of the method for forming the second coating 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 coating layer (B) is formed by the coating method will be described.

The formation of the second coating layer (B) by the coating method can be specifically formed 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.

The second coating liquid (b) may contain various additives in addition to the polyvalent metal compound, if necessary, 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 stables. Agents, film-forming agents, thickeners and the like can be mentioned.

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 coatability and film forming property of the second coating liquid (b). It is preferable to use a mixture of meltable or dispersible resins. Examples of such a resin include those similar to those mentioned as various additives that may be contained in the second coating layer (B).

Further, as an additive, it is preferable to mix a soluble or dispersible dispersant with the solvent used in the second coating liquid (b) for the purpose of improving the dispersibility of the polyvalent metal compound. Examples of the dispersant include those similar to those mentioned above as various additives that may be contained in the second coating layer (B).

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 for the second coating liquid (b) include water, methyl alcohol, ethyl alcohol, isopropyl alcohol, n-propyl alcohol, n-butyl alcohol, n-pentyl alcohol, dimethylsulfoxide, and dimethylformamide. , Dimethylacetamide, toluene, hexane, heptane, cyclohexane, acetone, methyl ethyl ketone, diethyl ether, dioxane, tetrahydrofuran, ethyl acetate, butyl acetate and the like. In addition, 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. Further, from the viewpoint of productivity, methyl alcohol, ethyl alcohol, isopropyl alcohol and water are preferable. Since the first gas barrier layer (A) formed from the first coating liquid (a) has excellent water resistance, water can be used as the solvent used for the second coating liquid (b). ..

The second coating liquid (b) is applied to a surface on which the second coating layer (B) is laminated, for example, on the first coating layer (A) to form a coating film, and the coating film is formed. The second coating 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, a casting method, a dipping method, a roll coating method, a gravure coating method, a screen printing method, and a reverse method can be selected. Examples 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 coating method, and a curtain coating method.

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

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. Any of these methods may be used alone or in combination of two or more. The drying temperature is not particularly limited, but when the above-mentioned water or a mixed solvent of water and an organic solvent is used as the solvent, it is usually preferably 50 ° C. to 160 ° C. Further, the pressure at the time of drying is usually performed under normal pressure or reduced pressure, and it is preferable to perform at normal pressure from the viewpoint of equipment convenience. When the second coating layer (B) thus formed contains a polyvalent metal compound, and further, when the second coating liquid (b) contains other components such as additives, , Applicable other ingredients are included.

Further, by providing a sealant layer (not shown) on the second coating layer (B) 5, it is possible to provide a gas barrier laminate that can be used as a more practical packaging material. The sealant layer is used for an adhesive portion when forming a bag-shaped package or the like, and is, for example, polyethylene, polypropylene, ethylene-vinyl acetate copolymer, ethylene-methacrylate copolymer, or ethylene-methacrylate. Resins such as ester copolymers, ethylene-acrylic acid copolymers, ethylene-acrylic acid ester copolymers, and metal crosslinked products thereof are used.

The thickness of the sealant layer is determined according to the purpose, but is generally in the range of 15 to 200 μm. Further, depending on the shape of the package, the sealant layer may be provided on the base material side or may be provided on both sides.

The PBT film of the film substrate 1 depends on the temperature, and the higher the temperature, the higher the elongation rate of the film. On the other hand, the thin-film deposition layer 3 cracks when the film is stretched, and the barrier does not appear. Depending on the temperature and tension in the drying oven when the coating liquids of the coating layer (A) 4 and the coating layer (B) 5 laminated on the vapor deposition layer 3 are applied and dried, the vapor deposition layer 3 cracks and becomes a barrier. No property, especially water vapor barrier property, is exhibited.

Therefore, as a result of diligent research by the present inventors, in roll coating, the tension and drying conditions when coating the coating layer (A) 4 and the coating layer (B) 5 without breaking the vapor deposition layer 3 are the above-mentioned vapor deposition. It was found that it can be specified by the parameter of the elongation rate in the film shape in which the layers 3 are laminated.

That is, the elongation rate Y (formula 1 below) in the film traveling direction (MD direction) when a tension of 10 to 70 N / m is applied at an arbitrary temperature may be 30% or less.
Elongation rate Y = ((length of film when tensioned at arbitrary temperature)-(length when tension is not applied at room temperature)) / (film length when tension is applied at arbitrary temperature) length)
... (Formula 1)

The elongation rate Y is preferably 15% or less. It is possible to set a wide processing margin under the tension conditions at the time of coating the coating layer (A) 4 and the coating layer (B) 5. The lower the elongation rate, the more the coating layer can be laminated by coating without breaking the thin-film deposition layer. It is necessary to confirm and set.

Thermomechanical analysis (TMA) is used as a method for measuring the elongation rate. TMA is a method of measuring deformation with respect to temperature while applying a non-oscillating load (constant load) to a sample. The load and temperature can be selected by assuming the tension and drying temperature during the roll coating process performed in the next process.

For example, it is assumed that the coating layer is formed by transporting the film with a tension of 60 N / m and drying the coating liquid at 80 ° C.
The drying temperature refers to the temperature actually applied to the film, not the set temperature of the dryer. For example, the above-mentioned heat label (a temperature measuring sticker in which the temperature indicating element is specially processed into a paper label, the indicated temperature is printed on the front surface, and the back surface is coated with a heat-resistant adhesive) is attached to the film. It is a temperature shown after applying (A1) component liquid and (A2) component liquid and drying.

Assuming roll coating, in Hitachi High-Tech Science (TA700), when the temperature of the film on which the vapor deposition layer 3 is laminated is changed from 50 ° C to 150 ° C with a film width of 4 mm and a load of 2N. When the elongation rate of the film is measured, in a film having a film elongation rate of more than 30% at 80 ° C., the vapor deposition layer 3 is cracked and the barrier property is not exhibited under the above-mentioned roll coating conditions.

On the other hand, even in a film in which the same thin-film deposition layer 3 is laminated, the elongation rate decreases as the drying temperature decreases. When the drying temperature is set to 50 ° C. and the film elongation rate is 30% or less, the vapor-filmed layer does not crack and exhibits barrier properties.

Further, even in a film in which the same thin-film deposition layer 3 is laminated, the elongation rate decreases as the tension decreases. When the elongation rate of the film was measured when the temperature was changed from 50 ° C to 150 ° C with a film width of 4 mm and a load of 0.4 N, the film elongation rate at a drying temperature of 80 ° C was measured even for the same film. When the temperature is 30% or less, the vapor-filmed layer does not crack and exhibits barrier properties.

Further, the inventor has found that if the elongation rate Y is equal to or less than the reference value G expressed by the following mathematical formula 2 on the film, the vapor-deposited layer exhibits barrier properties without being cracked by the coating. ..
That is, in the film shape in which the vapor-filmed layer made of the metal oxide is laminated, the elongation rate Y in the film traveling direction (MD direction) when a tension of 10 N / m to 70 N / m is applied is the film when the coating layer is formed. It is preferable that the value is not less than the reference value G shown in the following formula 2 according to the temperature X (° C.) and the tension Z (N / m).
Reference value G (%) = 0.8 x (temperature applied to the film X (° C.) -50) x (0.9 x (tension Z (N / m) -5) / 40) ... (Formula 2)
When a plurality of coating layers are formed on the film, the reference value G can be obtained for each coating layer forming condition, and the elongation ratio Y is a reference value for any coating layer forming condition. It is preferably G or less.

As a method of adjusting the elongation rate of the film base material 1 on which the thin-film deposition layer 3 is laminated, the elongation rate can be lowered by increasing the thickness of the film. Further, the elongation rate of the film can be adjusted by the film forming method or the stretching method of the PBT film as the base material. Further, the elongation rate can be adjusted by the thickness of the adhesion layer 2 and the selected resin component. Further, it is possible to adjust the elongation rate of the film before laminating the thin-film deposition layer by annealing the base film according to the tension and the drying temperature when laminating the adhesion layer 2 by coating.

As a method for forming the sealant layer, a dry laminating method in which a film made of the above-mentioned resin is bonded with a one-component curing type or two-component curing type urethane adhesive, and a non-solvent method for bonding using a solvent-free adhesive are used. Both can be formed by a known laminating method such as a dry laminating method, an extrusion laminating method in which the above-mentioned resin is heated and melted, extruded into a curtain shape, and bonded together. The dry laminating method is preferable for the high temperature hot water treatment. Any laminating method can be used as long as the treatment is performed at a temperature of 85 ° C. or lower.

Examples of the heat sterilization treatment method include retort treatment and boiling treatment. Retort treatment is a method of pressurizing and sterilizing microorganisms such as molds, yeasts, and bacteria in order to store foods and the like. Usually, the gas barrier laminate packaging material in which food is packaged is subjected to pressure sterilization treatment at 105 to 140 ° C. and 0.15 to 0.30 MPa under the conditions of 10 to 120 minutes.
There are two types of retort pouches, a steam type that uses heated steam and a hot water type that uses pressurized heated water, and they are used appropriately according to the sterilization conditions of the food or the like to be the contents.

Boil treatment is a method of moist heat sterilization for preserving foods and the like. Usually, although it depends on the contents, the gas barrier laminated body packaging material in which food or the like is packaged is subjected to moist heat sterilization treatment under the conditions of 60 to 100 ° C. and atmospheric pressure for 10 to 120 minutes. The boiling treatment is usually performed using a hot water tank, but there are a batch type in which the water is immersed in a hot water tank at a constant temperature and taken out after a certain period of time, and a continuous type in which the inside of the hot water tank is sterilized by passing through a tunnel type.

The gas barrier film 10 of the present invention has an oxygen permeability of preferably 50 cc / m ² · day · MPa or less at a temperature of 30 ° C. and a relative humidity of 70% RH, more preferably 30 cc.
It is less than / m ² · day · MPa. The lower the oxygen permeability, the more preferable, and the lower limit thereof is not particularly limited, but is usually 0.1 cc / m ² , day, MPa or more.

The gas barrier film 10 of the present invention has excellent gas barrier properties even if stress (abuse) such as stretching or bending is applied before the heat sterilization treatment is performed. For example, even after the abuse resistance is evaluated under the conditions described in Examples described later, the oxygen permeability at a temperature of 30 ° C. and a relative humidity of 70% has almost the same oxygen permeability as described above.

Specific examples of the present invention will be described below.

As the material of the adhesion layer 2, the coating liquid 1 was prepared by the following procedure.

[Coating solution 1]: Adhesive solution manufactured by Mitsui Chemicals, Inc. (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).

As the first coating liquid (a), the coating liquid 2 was prepared by the following procedure.
[Coating solution 2]: PAA (polyacrylic acid) aqueous solution having a number average molecular weight of 200,000 (Aron A-10H manufactured by Toagosei, solid content concentration 25% by mass) / GPTMS (γ-glycidoxypropyltrimethoxysilane) / Solvent: water, isopropyl alcohol (IPA)
This was blended at Aron A-10H: GPTMS: water: IPA = 10: 0.17: 66: 7 (solid content concentration 15% by mass).

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

As the second coating liquid (b), the coating liquid 3 was prepared by the following procedure.

[Coating solution 3]: Zinc oxide-containing resin composition: K035A (Sumitomo Osaka Cement Co., Ltd. 16.6% by mass of zinc oxide, 1.74% by mass of urethane resin precursor, 1.66% by mass of dispersant, 72% by mass of toluene , Methyl ethyl ketone 8% by mass) / Hardener: C-320 (including 75% by mass of urethane resin curing agent, 25% by mass of ethyl acetate) / 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)
A gravure coat was used on the corona-treated side of a biaxially stretched polybutylene terephthalate film (PBT, thickness 15 μm), which is a film base material, and the above coating liquid 1 was subjected to a gravure roll coating method to a tension of 70 N / m and a drying temperature. The coating was applied at 60 ° C., and the polyester resin was cured by 0.1 g / m ² to form the adhesion layer 2.
Next, as the metal oxide thin-film deposition layer, aluminum was evaporated while introducing oxygen by an electron beam type vacuum vapor deposition method to form an AlOx thin-film deposition film having a thickness of 10 nm. Next, the coating liquid 2 is coated under the conditions of a tension of 60 N / m and a drying temperature of 70 ° C. to form the first coating layer (A), and the coating liquid 3 is further subjected to a tension of 60 N / m and a drying temperature. The coating process was performed under the condition of 60 ° C. to form the second coating layer (B).
As a result, the adhesion layer (0.1 g / m ² ) / AlOx vapor deposition layer (10 nm) is placed on the film substrate.
) / PAA (0.4 g / m ² ) / ZnO (0.4 g / m ² as ZnO) to obtain a transparent gas barrier film.

As for the drying temperature, the actual temperature applied to the film was measured by attaching a thermo label (5-point display label CR manufactured by Ivy Giken Co., Ltd.) to the film at the time of coating and passing it through a drying oven.

<1> Evaluation of film elongation: [Measuring method of TMA]
Using a thermomechanical analyzer (TA700 manufactured by Hitachi High-Tech Science Co., Ltd.), cut the film on which the vapor-film-deposited film was formed to a width of 4 mm along the flow direction of the film, set it in the device, and set the tension to 60 N / m. The load was set to. The temperature was raised from 50 ° C. to 150 ° C. at 10 ° C./min, and the elongation rate Y of the film at 60 ° C. and 70 ° C. was measured. The film elongation rate Y is expressed by the following formula.
Elongation rate Y = ((length of film when tensioned at arbitrary temperature)-(length when tension is not applied at room temperature)) / (film length when tension is applied at arbitrary temperature) length)
... (Formula 1)

<2> Evaluation of gas barrier properties
The oxygen permeability and water vapor transmission rate of the obtained gas barrier film were measured. In addition, as an experimental example, a pouch was prepared using this gas barrier film and retort-treated.

[Measurement method of oxygen permeability]
The measurement was performed using an oxygen permeability measuring device (OXTRAN 2/20 manufactured by Modern Control) under the conditions of a temperature of 30 ° C. and a relative humidity of 70%. The measuring method was based on JIS K-7126, B method (isopressure method), and the measured values were expressed in units [cc / m ² , day, MPa] (N = 3 average value).

[Measurement method of water vapor transmission rate]
It was measured using a water vapor transmission rate measuring device (PERMATRAN 3/33 manufactured by Modern Control) under the conditions of a temperature of 40 ° C. and a relative humidity of 90%. The measuring method was based on JIS K-7126, B method (isopressure method), and the measured values were expressed in units [g / m ² · day] (N = 3 average value).

[Experimental Example 1]
An unstretched polypropylene film (CPP: Toray Film Processed Trefan NO ZK207, thickness 70 μm) was placed on the ZnO layer of the gas barrier film of Example 1 using a two-component adhesive (Mitsui Chemicals A525 / A52). Laminating by the dry laminating method, a laminated film having a composition of [transparent gas barrier film / adhesive layer / CPP (70 μm)] was obtained.

Next, the obtained laminated film was impulse-sealed in a 15 cm × 10 cm pouch shape, 200 ml of tap water was added to the contents, and the remaining one side was impulse-sealed to prepare a four-way pouch. This pouch was retorted (heated with hot water) at 0.2 MPa and 121 ° C. for 30 minutes using a retort device.

(Example 2)
A transparent gas barrier film was obtained in the same manner as in Example 1 except that a biaxially stretched polybutylene terephthalate film (PBT, thickness 25 μm) was used as the film substrate. Subsequently, a pouch was prepared by laminating with an adhesive in the same manner as in Experimental Example 1 above, and a pouch treated in the same manner was obtained.

(Example 3)
A transparent gas barrier film was obtained in the same manner as in Example 1 except that a polybutylene terephthalate film (PBT, thickness 15 μm) stretched and formed by an inflation method was used as a film substrate. Subsequently, a pouch was prepared by laminating with an adhesive in the same manner as in Experimental Example 1, and a pouch treated in the same manner was obtained.

(Comparative Example 1)
A transparent gas barrier film was obtained in the same manner as in Example 1 except that a biaxially stretched polybutylene terephthalate film (PBT, thickness 9 μm) was used as the film substrate. Subsequently, a pouch was prepared by laminating with an adhesive in the same manner as in Experimental Example 1, and a pouch treated in the same manner was obtained.

(Comparative Example 2)
A transparent gas barrier film is obtained by applying coating solutions 1 to 3 in the same manner as in Example 1 using a gravure coat on the corona-treated side of a biaxially stretched polyethylene terephthalate film (PET, thickness 12 μm) which is a film base material. rice field. Subsequently, a pouch was prepared by laminating with an adhesive in the same manner as in Experimental Example 1, and a pouch treated in the same manner was obtained.

(Comparative Example 3)
A transparent gas barrier film is obtained by applying coating solutions 1 to 3 in the same manner as in Example 1 using a gravure coat on the corona-treated side of a biaxially stretched polyethylene terephthalate film (PET, thickness 12 μm) which is a film base material. rice field. Next, on the ZnO layer of the transparent gas barrier laminate, a biaxially stretched nylon film (ONY: ONBC thickness 15 μm manufactured by Unitika) was applied by a dry laminating method using a two-component adhesive (Mitsui Kagaku A525 / A52). Laminate and then laminate unstretched polypropylene film (CPP: Toray Film Processing Trefan NO ZK207, thickness 70 μm) on ONY by dry laminating method using a two-component adhesive (Mitsui Kagaku A525 / A52). Then, a laminated film having a composition of [transparent gas barrier film / adhesive layer / ONY (15 μm) / adhesive layer / CPP (70 μm)] was obtained. Subsequently, a pouch was prepared in the same manner as in Experimental Example 1 and retort-treated to obtain a pouch.

The pouch evaluation after the retort (hot water heating) treatment is described below. After the retort treatment, the tap water inside was discarded and the evaluation was performed in a sufficiently dried state.

<3> Evaluation of gas barrier property after retort treatment [Measurement method of oxygen permeability]
The measurement was performed using an oxygen permeability measuring device (OXTRAN 2/20 manufactured by Modern Control) under the conditions of a temperature of 30 ° C. and a relative humidity of 70%. The measuring method was based on JIS K-7126, B method (isopressure method), and the measured values were expressed in units [cc / m ² , day, MPa] (N = 3 average value).

<4> Evaluation of low temperature drop test After storing a pouch containing 200 ml of water in an environment of 5 ° C for 24 hours, the pouch is freely dropped from a height of 1 m from the floor to the floor and the bag is torn. The number of times was confirmed (N = 3, maximum number of drops 50 times).

The above evaluation results are shown in Tables 1 and 2 below.

Table 1 is an evaluation of the film before laminating the sealant (CPP film). As shown in Table 1 (b), in Examples 1 to 3, since the elongation rates Y of the vapor-filmed films at 70 ° C. and 60 ° C. are both within 30%, oxygen permeation of the gas barrier film laminated with the coating layers 4 and 5 is performed. The degree and water vapor transmission rate were low, indicating that barrier properties were exhibited.
On the other hand, in Comparative Example 1, the elongation rate Y at 60 ° C. of the vapor-filmed film was within 30%, but the elongation rate at 70 ° C. was 35%, which greatly exceeded 30%, so that the barrier of the gas barrier laminated film was developed. It does not have a particularly low water vapor barrier property.

Table 2 shows the evaluation of the sealant (CPP film) in the state after laminating as a practical test of the pouch.
As shown in Table 2, in the practical test, Examples 1 to 3 maintain high barrier properties even after retort.
On the other hand, in Comparative Example 1, both the oxygen barrier property and the water vapor transmission rate have large values, and the barrier property is not exhibited. It is considered that this is because the thickness of the base material was too thin as compared with the examples, so that the elongation rate Y of the film was high, Y> G with respect to the reference value G, and the vapor deposition layer was cracked and the barrier property was deteriorated. Be done.
Further, Comparative Examples 2 and 3 are PET base materials and show the same barrier properties as those of Examples 1 to 3, but the toughness of the film by the drop test is such that bag breakage occurs in Comparative Example 2 which is a PET film. However, while the toughness of the film is poor, the film does not break in Examples 1 to 3, and even if the configuration does not use PET and ONY, it has a strong impact comparable to the PET / ONY / CPP configuration of Comparative Example 3. Shown the strength.

The gas barrier laminate of the present invention can obtain sufficient low-temperature drop impact strength after hot water heat treatment even if the layer structure of the packaging material for retort pouch is simplified to two by using a biaxially stretched PBT film as a base material. It can be used as a packaging member suitable for boiling and retort applications, which has excellent barrier properties.

1 Film base material
2 Adhesive layer
3 Thin-film deposition layer 4 First coating layer (A)
5 Second coating layer (B)

Claims (6)

A vapor-deposited layer made of an inorganic oxide or a metal oxide, a first coating layer, and a second coating layer are formed on one surface of a film substrate containing a polyester resin having a butylene terephthalate unit as a main constituent unit. Are stacked in this order,
The first coating layer is selected from the group consisting of a polycarboxylic acid-based polymer, a silane coupling agent represented by the general formula ^R1Si (OR ² ) ₃ , a hydrolyzate thereof, and a condensate thereof. A layer containing at least one silicon-containing compound in a mass ratio of 99.5: 0.5 to 80.0: 20.0.
The second coating layer is a layer containing a polyvalent metal compound, and is a layer containing a polyvalent metal compound.
A gas barrier film characterized in that the thickness of the film base material is 12 μm or more.
The film base material is a stretched film.
When a tension of 10 N / m to 70 N / m is applied to the gas barrier film at a temperature of 50 ° C. to 150 ° C., the elongation rate Y (formula 1 below) in the film traveling direction (MD direction) is 30% or less. A gas barrier film characterized by that.
Elongation rate Y = ((length of film when tensioned at a predetermined temperature)-(length when tension is not applied at room temperature))) / (length of film when tension is applied at a predetermined temperature) Length) ・ ・ ・ (Formula 1)
(However, R ¹ is an organic group containing a glycidyloxy group or an amino group, R ² is an alkyl group, and the three R ^2s do not have to be the same.) In the gas barrier film, the elongation rate Y is Y ≦ G with respect to the reference value G represented by the following formula 2 depending on the temperature X (° C.) and the tension Z (N / m) applied to the arbitrary film. The gas barrier film according to claim 1.
Reference value G (%) = 0.8 x (temperature applied to the film X (° C.) -50) x (0.9 x (tension Z (N / m) -5) / 40) ... (Formula 2) The gas barrier film according to claim 1 or 2, wherein an adhesion layer containing an anchor coating agent is provided between the film base material and the thin-film deposition layer. The gas barrier film according to claim 3, wherein the adhesive layer contains a polyester-based polyurethane resin and a polyether-based polyurethane resin. The gas barrier film according to any one of claims 1 to 4, wherein the inorganic oxide is aluminum oxide or silicon oxide. The gas barrier film according to any one of claims 1 to 5, wherein the polycarboxylic acid-based polymer has a number average molecular weight in the range of 2,000 to 10,000,000.

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