JP2019181960A - Gas barrier laminate film - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a gas-barrier laminated film and a gas-barrier packaging bag which can be used for packaging of confectionery, daily necessities, electronic parts, pharmaceuticals and the like which require moisture-proof properties. SOLUTION: This is a gas barrier laminated film in which an inorganic thin film layer and a gas barrier resin composition layer are laminated on at least one surface of a plastic film, wherein the gas barrier resin composition layer is polyvinyl alcohol or butenediol / vinyl. The gas barrier resin composition layer contains an alcohol copolymer and has a water vapor permeability of 0.9 g / m 2 · d or less at 40 ° C. and 90% RH when the inorganic thin film layer is laminated. A gas barrier laminated film having a high humidity dependency, wherein the ratio of water vapor barrier properties at 40 ° C. and 35% RH to 40 ° C. and 90% RH is 15 to 100 times. [Selection diagram] None

Description

  The present invention relates to a gas barrier laminate film having transparency, excellent gas barrier properties against water vapor, oxygen, and the like, and suitable for applications requiring high moisture resistance such as confectionery, daily necessities, electronic parts, and pharmaceuticals.

Conventionally, a film in which a metal thin film such as aluminum or a thin film of inorganic oxide such as silicon oxide or aluminum oxide is laminated on the surface of a plastic film has been known as a gas barrier film. In particular, films made by laminating thin films of inorganic oxides such as silicon oxide, aluminum oxide, and mixtures of these are transparent, and the contents can be confirmed, so food, household goods, electronic parts, pharmaceuticals, etc. Widely used in packaging applications. (For example, see Patent Document 1)
In these inorganic thin films, pinholes, cracks and the like are easily generated in the thin film forming process, and the inorganic thin film layer is cracked and cracked in the processing process, and sufficient gas barrier properties as expected are not obtained.

  Many gas barrier films have also been proposed by coating the surface of a plastic film with a resin composition. In particular, polyvinyl alcohol (hereinafter referred to as PVA) and ethylene-vinyl alcohol copolymer (hereinafter referred to as EVOH) have high oxygen barrier properties themselves and are put into practical use as gas barrier coating agents, and are widely known as known techniques. However, gas barrier properties are not obtained.

Therefore, in order to compensate for the lack of barrier properties of the deposited film with the gas barrier resin, the above-described vinyl alcohol resin, particularly a barrier resin such as PVA, was laminated on the inorganic thin film layer, but the water vapor barrier property was sufficient. Not expressed. This is considered to be because the gas barrier property of PVA depends on humidity, and the gas barrier property is significantly lowered under high humidity.
In view of this, a gas barrier film in which an inorganic thin film layer is coated with EVOH having a gas barrier property that is less dependent on humidity than PVA has been proposed (for example, see Patent Documents 3 and 4). The demand for quality, especially the improvement of moisture-proof performance is required, so the current performance is not satisfactory.

Japanese Patent No. 2929609 Japanese Patent Laid-Open No. 7-80986 JP 2005-349769 A JP 2008-297527 A

  The present invention has been made against the background of such prior art problems. That is, an object of the present invention is to provide a gas barrier laminate film and gas barrier property that can be used for packaging applications such as confectionery, daily necessities, electronic parts, and pharmaceuticals that require a high degree of moisture resistance that cannot be obtained with conventional vapor deposition films. To provide a packaging bag.

As a result of intensive studies, the present inventors have found that the above problems can be solved by the following means, and have reached the present invention.
That is, this invention consists of the following structures.

A gas barrier laminate film obtained by laminating an inorganic thin film layer and a gas barrier resin composition layer on at least one surface of a base film, wherein the gas barrier resin composition layer is polyvinyl alcohol or butenediol / vinyl alcohol copolymer The base film on which the inorganic thin film layer is laminated and has a water vapor permeability of 0.9 g / m ² · d or less at 40 ° C. and 90% RH, and the gas barrier resin composition layer is 40 ° C. A gas barrier laminate film comprising a highly moisture-dependent film having a water vapor barrier property ratio of 15 to 100 times at 35% RH and 40 ° C. and 90% RH.

  Moreover, in this case, it is preferable that the additive added to the gas barrier resin layer contains at least one hydrogen bonding group crosslinking agent.

  Furthermore, in this case, it is preferable that the inorganic thin film layer contains at least one multi-component inorganic oxide containing silicon oxide and aluminum oxide.

  Furthermore, in this case, the gas barrier packaging bag in which any one of the above gas barrier laminated films is arranged in the order of the base film layer, the inorganic thin film layer, and the gas barrier resin composition layer from the outside of the bag.

  According to the present invention, it is possible to obtain a gas barrier laminate film having a gas barrier property against water vapor, oxygen and the like, in particular, a moisture-proof property under high humidity, compared to conventional ones.

The present invention is a gas barrier laminate film in which an inorganic thin film layer and a gas barrier resin composition layer are laminated on at least one surface of a plastic film, and the water vapor permeability of the plastic film in which the inorganic thin film layer is laminated is 40. ° C., during 90% RH, or less 0.9g / ^{m 2} · d, and the gas barrier resin composition is 40 ℃, 35% RH at a 40 ° C., the ratio of water vapor barrier properties at 90% RH 15 The gas barrier laminate film is characterized in that it is made of a film having a high humidity dependency of ˜100 times. Each component will be described in detail below.

1. Base Film The base film used in the present invention is a film made of an organic polymer and subjected to stretching, cooling, and heat setting in the longitudinal direction and / or the width direction as necessary after melt extrusion. Examples of the organic polymer include polyamides represented by nylon 4, 6, nylon 6, nylon 6, 6, nylon 12, etc., polyesters represented by polyamide, polyethylene terephthalate, polybutylene terephthalate, polyethylene-2,6-naphthalate, polyethylene, and the like. In addition to polyolefins typified by polypropylene, polybutene, etc., polyvinyl chloride, polyvinylidene chloride, polyvinyl alcohol, wholly aromatic polyamide, polyamideimide, polyimide, polyetherimide, polysulfone, polystyrene, polylactic acid and the like can be mentioned. .
The base film in the present invention may be a laminated film. There are no particular limitations on the type of layers, the number of layers, the lamination method, and the like in the case of a laminated film, and any one of known methods can be selected according to the purpose.
The base film may be copolymerized or blended with a small amount of another organic polymer. About the manufacturing method of a base film, the existing methods, such as a co-extrusion method and a casting method, can be used.

  Among these, specific examples of preferred polyamides include polycaproamide (nylon 6), poly-ε-aminoheptanoic acid (nylon 7), poly-ε-aminononanoic acid (nylon 9), polyundecanamide (nylon 11). ), Polylaurin lactam (nylon 12), polyethylene diamine adipamide (nylon 2.6), polytetramethylene adipamide (nylon 4.6), polyhexamethylene adipamide (nylon 6/6), polyhexa Methylene sebacamide (Nylon 6 · 10), Polyhexamethylene dodecane (Nylon 6 · 12), Polyoctamethylene dodecane (Nylon 6 · 12), Polyoctamethylene adipamide (Nylon 8 · 6), Polydeca Methylene adipamide (nylon 10/6), polydecamethylene sebacamide (Niro 10), polydodecamethylene dodecamide (nylon 12 · 12), metaxylenediamine-6 nylon (MXD6), and the like. Examples include caprolactam / laurin lactam copolymer, caprolactam / hexamethylene diammonium adipate copolymer, laurin lactam / hexamethylene diammonium adipate copolymer, hexamethylene diammonium adipate / hexamethylene diammonium sebacate copolymer And ethylene diammonium adipate / hexamethylene diammonium adipate copolymer, caprolactam / hexamethylene diammonium adipate / hexamethylene diammonium sebacate copolymer, and the like. It is also effective to blend these polyamides with plasticizers such as aromatic sulfonamides, p-hydroxybenzoic acid, esters, elastomer components with low elastic modulus, and lactams as film flexibility modifiers. is there.

Specific examples of preferable polyesters include polyethylene terephthalate, polybutylene terephthalate, polyethylene-2,6-naphthalate, and the like. A copolymer having these as a main component may be used. When used, the main component of the dicarboxylic acid component is aromatic dicarboxylic acid such as terephthalic acid, isophthalic acid, phthalic acid or 2,6-naphthalenedicarboxylic acid, polyfunctional carboxylic acid such as trimellitic acid and pyromellitic acid. In addition, aliphatic dicarboxylic acids such as adipic acid and sebacic acid are used.
In addition, ethylene glycol or 1,4-butanediol is used as the main component of the glycol component. In addition, aliphatic glycols such as diethylene glycol, propylene glycol, and neopentyl glycol, aromatic glycols such as p-xylylene glycol, Alicyclic glycols such as 1,4-cyclohexanedimethanol and polyethylene glycol having an average molecular weight of 150 to 20000 can also be used.
The ratio of the preferable copolymerization component in polyester is 2% or less. When the copolymerization component exceeds 20%, the film strength, transparency, heat resistance, etc. may be inferior.

Furthermore, known additives such as ultraviolet absorbers, antistatic agents, plasticizers, lubricants, colorants, etc. may be added to the organic polymer, and the transparency as a base film is particularly limited. Although it is not a thing, when using as a packaging material laminated body which has transparency, what has the transmittance | permeability of 50% or more is desirable.
The base film in the present invention is subject to corona discharge treatment, glow discharge, flame treatment, surface roughening treatment, etc. prior to laminating the thin film layer as long as the object of the present invention is not impaired. A surface treatment may be applied, and a known anchor coat treatment, printing, and decoration may be applied. The plastic film in the present invention desirably has a thickness of 1 to 500 μm, more preferably 2 to 300 μm, and most preferably 3 to 100 μm.

2. Inorganic thin film layer The material for forming the inorganic thin film layer in the present invention is not particularly limited as long as it can be formed into a thin film such as magnesium, aluminum, titanium, chromium, nickel, and indium in the case of a metal thin film. Aluminum is preferable.

Examples of the inorganic thin film layer in the present invention include an inorganic oxide thin film in addition to the metal thin film. For example, silicon oxide, aluminum oxide, magnesium oxide and the like that can be made into a thin film are not particularly limited, but are preferably silicon oxide, aluminum oxide, magnesium oxide, and more preferably multi-component inorganic oxidation containing silicon oxide and aluminum oxide. The physical thin film has better gas barrier properties. The reason is that the multi-component inorganic oxide thin film can change the flexibility and barrier properties of the film depending on the ratio of inorganic substances in the thin film, and can obtain a good thin film with a balanced performance. It is. Moreover, it is because a high adhesive force is easily obtained between the multi-component inorganic oxide thin film containing silicon oxide and aluminum oxide and the adhesive layer, and the heat-sealable resin layer is difficult to peel off.
As used herein, the multi-component inorganic oxide thin film containing silicon oxide and aluminum oxide is a thin film formed from an inorganic oxide by a known method, and the inorganic oxide includes silicon oxide, aluminum oxide, The inorganic oxide is not particularly limited as long as it can be formed into a thin film such as magnesium oxide, but a preferable inorganic oxide is a multi-component inorganic oxide thin film containing aluminum oxide and silicon oxide, more preferably a binary system composed of silicon oxide and aluminum oxide. It is an inorganic oxide thin film.
The silicon oxide here is composed of a mixture of various silicon oxides such as Si, SiO and SiO _2, and the aluminum oxide is composed of a mixture of various aluminum oxides such as AlO and Al ₂ O ₃ , The amount of oxygen bound in the film varies depending on the production conditions.

  The specific gravity of the binary inorganic oxide thin film composed of silicon oxide and aluminum oxide is determined by the specific gravity of the thin film and the content of aluminum oxide in the thin film (mass%) D = 0.01A + b (D: specific gravity of the thin film, A: in the thin film) The b value is preferably from 1.2 to 2.2, more preferably from 1.7 to 2.1.

  Further, the relationship between the specific gravity value of the binary inorganic oxide thin film and the content (mass%) of aluminum oxide in the inorganic oxide thin film is expressed as D = 0.01A + b (D: specific gravity of the thin film, A: thin film) When the b value is a region smaller than 1.6, the structure of the silicon oxide / aluminum oxide thin film becomes rough, and the b value is larger than 2.2. In this case, the silicon oxide / aluminum oxide thin film tends to be hard.

The content of aluminum oxide in the binary inorganic oxide thin film is preferably 20 to 99% by mass, and more preferably 20 to 75% by weight.
When the content of aluminum oxide in the binary inorganic oxide thin film is less than 20% by mass, the gas barrier property is not necessarily sufficient, and when the amount of aluminum oxide in the binary inorganic oxide thin film exceeds 99% by mass, The flexibility of the deposited film is lowered, the gas barrier laminate is relatively vulnerable to bending and dimensional changes, and the effect of the combined use may be reduced.

  In this invention, the film thickness of an inorganic thin film layer is 1-50 nm normally, Preferably it is 5-30 nm. If the film thickness is less than 1 nm, it is difficult to obtain satisfactory gas barrier properties, and even if the thickness exceeds 50 nm, excessive gas barrier properties cannot be obtained. On the contrary, it is disadvantageous.

The typical manufacturing method for forming the inorganic thin film layer is explained by the formation of a silicon oxide / aluminum oxide thin film. As a thin film forming method by a vapor deposition method, a physical vapor deposition method such as a vacuum heating vapor deposition method, a sputtering method, an ion plating method, Or CVD method (chemical vapor deposition method) etc. are used suitably. For example, when the vacuum deposition method is employed, a mixture of SiO ₂ and Al ₂ O ₃ or a mixture of SiO ₂ and Al is used as a deposition material. For heating, resistance heating, high-frequency induction heating, electron beam heating, etc. can be adopted, oxygen, nitrogen, hydrogen, argon, carbon dioxide gas, water vapor, etc. are introduced as reaction gases, ozone addition, ion assist It is also possible to employ reactive vapor deposition using such means. Furthermore, the film forming conditions can be arbitrarily changed, such as applying a bias to the plastic film or heating or cooling the plastic film. The vapor deposition material, reaction gas, substrate bias, heating / cooling, and the like can be similarly changed when a sputtering method or a CVD method is employed.

The water vapor permeability of a plastic film in which an inorganic thin film layer is laminated on the film is required to be 0.9 g / m ² · d or less at 40 ° C. and 90% RH, and the water vapor permeability at 40 ° C. and 90% RH. Is greater than 0.9 g / m ² · d, moisture resistance is not sufficient. The reason for this will be described in the gas barrier resin composition layer.

3. Gas Barrier Resin Composition Layer The gas barrier resin composition layer in the present invention preferably uses PVA or BVOH as the gas barrier resin, and further comprises a gas barrier resin composition containing an additive.

(1) Gas barrier resin Conventionally, PVA and BVOH are known to have high oxygen barrier properties themselves, and have been widely used as oxygen barrier resins, but water vapor barrier properties under high humidity are It has been regarded as unsuitable as a barrier resin that exhibits poor moisture resistance.
These have higher humidity barrier dependency on water vapor barrier than EVOH, and the water vapor barrier property under high humidity is very poor. However, paying attention to the fact that the water vapor barrier property under low humidity is rather high so that it can be combined with an inorganic thin film layer with good water vapor barrier properties, and the side opposite to the inorganic thin film layer should also be under low humidity. Surprisingly, it has been found that by disposing a layer containing a gas barrier resin, the moisture barrier property is much higher than when using a barrier resin having a moisture barrier property with low humidity dependency.
This is considered to be because a large amount of moisture is stopped by the inorganic thin film layer having a good water vapor barrier property, and the barrier resin layer disposed next is in a low humidity environment.
BVOH is characterized by high humidity dependency similar to PVA, and also has a higher solution stability at low temperatures than PVA, and very good production stability when used as a coating agent. More preferred.
The reason why PVA and BVOH have poor water vapor barrier properties at higher humidity than EVOH is considered to be related to the amount of OH groups. A large amount of OH groups is expected to increase the number of hydrogen bonding moieties. Further, it is considered that the hydrogen bond portion has a great influence on the gas permeation, and the gas permeation can be suppressed as the hydrogen bond portion increases. However, since the hydrogen bonding portion is cut when water enters, it is expected that the gas barrier property is lowered at a high humidity when a large amount of water comes. Since PVA and BVOH have a larger amount of OH groups than EVOH, they exhibit a high barrier property at low humidity but are not good at high humidity.

The high humidity dependency mentioned here means high humidity dependency in which the ratio of the water vapor barrier property at 40 ° C. and 35% RH to the water vapor barrier property at 40 ° C. and 90% RH of the gas barrier resin composition layer is 15 to 100 times. Means that.
The humidity dependency of the gas barrier resin composition layer at this time is a value obtained by measurement as follows.
First, the gas barrier resin composition is laminated on the biaxially stretched PET film so as to have a dry coat thickness of 1 μm by bar coating to produce a gas barrier resin composition layer laminated film. This laminated film was installed in a water vapor transmission rate measuring device (PERMATRAN-W3 / 33MG MOCON) so that the surface of the gas barrier resin composition layer is on the flow side of the humidity control gas of the measuring device, and in accordance with JIS K7126 B method. Similarly, a value (a) obtained by measuring WVTR in an atmosphere at a temperature of 40 ° C. and a humidity of 35% RH and a value (b) obtained by measuring WVTR in an atmosphere at a temperature of 40 ° C. and a humidity of 90% RH are obtained. The humidity control on the laminated film was carried out for 4 hours in such a direction that water vapor permeates from the gas barrier resin composition layer side to the base film side.
The obtained results were applied to the following formula to determine the humidity dependency of the gas barrier resin composition layer.
Humidity dependency of gas barrier resin composition layer = (b) / (a)

The butenediol-vinyl alcohol copolymer (BVOH), which is an example of the gas barrier resin used in the present invention, is specifically a Nichigo G polymer (degree of saponification of 99.5 mol% or more, average polymerization) manufactured by Nippon Synthetic Chemical Industry. A degree of 300 or more, a melting point of 185 ° C. or more, and an MFR of 3.0 g / 10 min or more).
Specifically, PVA made by Kuraray (having a saponification degree of 98.0 mol% or more and an average polymerization degree of 300 or more is preferable as the PVA.

(2) Additive In the present invention, the gas barrier resin composition layer may contain at least one crosslinking agent as an additive, and the crosslinking agent is 0.3 to 100% by mass with respect to 100% by mass of the gas barrier resin composition. It is preferable to add 20% by mass. More preferably, it is 0.5-18 mass%, More preferably, it is 5-18 mass%.
The crosslinking agent is preferably a hydrogen bonding crosslinking agent, and preferably contains at least one kind.

(Hydrogen bond crosslinking agent)
Examples of the hydrogen bonding group crosslinking agent include water-soluble zirconium compounds and water-soluble titanium compounds. Specific examples of water-soluble zirconium compounds include zirconium chloride, hydroxy zirconium chloride, basic zirconium sulfate, zirconium nitrate, ammonium zirconium carbonate, sodium zirconium sulfate, sodium zirconium citrate, zirconium lactate, zirconium acetate, zirconium sulfate, zirconium oxysulfate Zirconium oxynitrate, basic zirconium carbonate, zirconium hydroxide, zirconium carbonate potassium, zirconium chloride, zirconium chloride octahydrate, zirconium oxychloride, etc. From the viewpoint of the stability of the coating composition, zirconium hydrochloride and hydroxyzirconium chloride are preferred, and zirconium hydroxide is particularly preferred. These may be used alone or in combination of two or more.
Examples of water-soluble titanium compounds include titanium lactate, titanium lactate ammonium salt, diisopropoxy titanium (triethanolamate), di-n-butoxytitanium bis (triethanolamate), diisopropoxytitanium bis (triethanol). Aminates), titanium tetrakis (acetylacetonate), etc., and examples of zirconium compounds are monohydroxytris (lactate) zirconium ammonium, tetrakis (lactate) zirconium ammonium, monihydroxytris (slate) zirconium ammonium, etc. It is not limited to. These may be used alone or in combination of two or more.

(3) Laminating method As a method of laminating the gas barrier resin composition layer on the inorganic thin film layer, a coating solution prepared by dissolving and dispersing each material of the gas barrier resin composition in a solvent is used for the film having the inorganic thin film layer. A method of coating on an inorganic thin film layer, a method of melting a gas barrier resin composition and extruding it onto an inorganic thin film layer of a film having an inorganic thin film layer, and separately preparing a film of a gas barrier resin composition Can be applied to the inorganic thin film layer of the film having the inorganic thin film layer with an adhesive or the like. Among these, the method by coating is preferable from the viewpoints of simplicity and productivity.

Hereinafter, as a preferred laminating method, a method of coating a coating liquid prepared by dissolving and dispersing each material of the gas barrier resin composition in a solvent on the inorganic thin film layer of the film having the inorganic thin film layer will be described.
As the solvent (solvent) of the gas barrier resin composition, any of aqueous and non-aqueous solvents capable of dissolving PVA and BVOH can be used, but water or a mixed solvent of water and isopropyl alcohol is preferably used. As the coating method, conventional products such as gravure coating, bar coating, die coating, and spray coating can be employed in accordance with the characteristics of the coating liquid.

(4) Thickness of gas barrier resin composition layer The thickness (μm) of the gas barrier resin composition layer is preferably 0.01 to 0.70 μm, more preferably 0.05 to 0.50 μm, and particularly preferably. Is 0.08 to 0.50 μm. If it is less than 0.01 μm, the gas barrier property is lowered, and if it exceeds 0.70 μm, insufficient drying occurs at the time of coating, resulting in problems such as blocking with the created roll, and the gas barrier resin composition layer becomes brittle and the laminate strength May decrease.

(5) Drying conditions of gas barrier resin composition layer The drying temperature after coating of the coating liquid of the gas barrier resin composition is preferably 100 to 200 ° C, more preferably 130 to 200 ° C, and still more preferably. 150-200 ° C. When the temperature is lower than 100 ° C., the coating layer is insufficiently dried, and the produced roll has problems such as blocking. Further, the gas barrier resin composition layer becomes brittle and the laminate strength is lowered.
On the other hand, when the temperature exceeds 200 ° C., the film is excessively heated and the base film becomes brittle or contracts, resulting in poor workability.

(6) Lamination order of gas barrier laminate film In order to express the moisture resistance of the gas barrier laminate film, the base film layer, the inorganic thin film layer, and the gas barrier resin composition layer may be arranged in this order from the high humidity side. is necessary. By disposing the inorganic thin film layer on the higher humidity side than the gas barrier resin composition layer having a large humidity dependence, it is possible to prevent a decrease in barrier properties due to the gas barrier resin composition layer being under high humidity.
At this time, the water vapor permeability at 40 ° C. and 90% RH of the base film on which the inorganic thin film layer is laminated needs to be 0.9 g / m ² · d or less.

In addition, the gas barrier property measuring method at this time is as follows.
(7) Water Vapor Permeability A substrate film on which the above-mentioned inorganic thin film layer is laminated or a gas barrier laminated film in which a substrate film, an inorganic thin film layer and a gas barrier resin composition layer are laminated on a water vapor permeability measuring device (PERMATRAN-W3 / 33MG MOCON) so that the surface of the base film of the gas barrier laminate film is on the flow side of the humidity control gas of the measuring instrument, and the temperature is 40 ° C. and the humidity is 90% RH according to JIS K7126 B method. The water vapor permeability was measured under the atmosphere of The humidity control on the gas barrier laminated film was carried out for 4 hours in such a direction that water vapor permeates from the film substrate side to the gas barrier resin composition layer side (or the inorganic thin film layer side).

The gas barrier laminate film of the present invention can be used for various applications including food packaging applications, and in addition to this, a heat seal layer, a printed layer, other resin films, and an adhesive for bonding these layers. It can be laminated with other materials such as layers. When laminating, it is possible to employ known means such as a method of directly melt-extrusion laminating on the gas barrier laminate film of the present invention, a method of coating, a method of laminating films directly or via an adhesive. I can do it.
When high gas barrier properties are required, two or more gas barrier laminate films of the present invention can be laminated. In addition, an inorganic vapor deposition layer may be further provided on the gas barrier resin composition layer, or a gas barrier resin composition layer may be further provided on the gas barrier resin composition layer. Furthermore, you may provide an inorganic vapor deposition layer, a gas-barrier resin composition layer, and an anchor layer etc. as needed on both surfaces of a base film.
For example, when using as a lid or packaging bag for confectionery, daily necessities, electronic parts, pharmaceuticals, etc. that require moisture resistance, a heat seal layer such as polyethylene or polypropylene is provided on the gas barrier resin composition layer. Is preferred. Further, another resin film may be laminated between the gas barrier resin layer and the heat seal layer. As other resin films, the resin films as mentioned as the base film can be used. In the case of laminating these, they can be laminated via an adhesive.
In particular, it is preferable to install a material that adsorbs moisture, such as a desiccant, inside the container or packaging bag.

  The gas barrier laminate film of the present invention is used for a packaging bag that protects the contents from external moisture, such as a base film, an inorganic thin film layer, and a gas barrier resin composition layer in order from the outside where the humidity becomes high. Is particularly effective.

  The present invention will be described in more detail with reference to the following examples, but the present invention is not limited to these examples. Unless otherwise specified, “%” means “% by mass”, and “part” means “part by mass”. In addition, the evaluation method of the physical property in a following example and a comparative example is as follows.

(1) Oxygen permeability of inorganic thin film laminate film The surface of the base film of the inorganic thin film laminate film is measured with an oxygen permeability measuring device (manufactured by OX-TRAN 2/20 MOCON). It installed so that it might become a flow side, and according to JISK7126-2 method, the oxygen permeability was measured in the atmosphere of temperature 23 degreeC and humidity 65% RH. In addition, humidity control to the inorganic thin film laminated film was carried out for 4 hours at a humidity of 65% RH on both the inorganic thin film laminated side and the film substrate side.

(2) Solution stability Each solution was stored in a low temperature environment of 5 ° C. and 50% RH, and the stability of the solution was evaluated. For evaluation, the degree of thickening over time was simply evaluated using “Iwata Viscosity Cup NK-2” manufactured by Anest Iwata.

(3) Humidity Dependence of Water Vapor Permeability of Gas Barrier Resin Composition Layer Gas barrier resin composition layer obtained by laminating a gas barrier resin composition on a biaxially stretched PET film so as to have a dry coat thickness of about 1 μm by bar coating. Create a laminated film.
This laminated film was installed in a water vapor transmission rate measuring device (PERMATRAN-W3 / 33MG MOCON) so that the surface of the gas barrier resin composition layer is on the flow side of the humidity control gas of the measuring device, and in accordance with JIS K7126 B method. Accordingly, a value (a) obtained by measuring WVTR in an atmosphere at a temperature of 40 ° C. and a humidity of 35% RH and a value (b) obtained by measuring WVTR in an atmosphere at a temperature of 40 ° C. and a humidity of 90% RH are obtained. The humidity control on the gas barrier laminate film was carried out for 4 hours in such a direction that water vapor permeates from the gas barrier resin composition layer side to the film substrate side.
Using the obtained value, it was applied to the following formula as a measure of the humidity dependence of the gas barrier resin composition layer. Humidity dependency of gas barrier resin composition layer = (b) / (a)

(4) Water Vapor Permeability of Gas Barrier Laminate Film The gas barrier laminate film obtained in Examples / Comparative Examples was added to a water vapor permeability measuring device (PERMATRAN-W3 / 33MG MOCON) as a base film for the gas barrier laminate film. It installed so that the surface might become the flow side of the humidity control gas of a measuring machine, and according to JISK7126B method, the water-vapor-permeation rate was measured in the atmosphere of temperature 40 degreeC, and humidity 90% RH. The humidity control on the gas barrier laminate film was carried out for 4 hours in such a direction that water vapor permeates from the film base layer side to the gas barrier resin composition layer side.

(5) Evaluation of moisture resistance in bag-made products A bag of about 100 mm square with three sides sealed was prepared using the laminated gas barrier laminate film shown in (7) above. The bag is filled with “Dryness Test Paper Product Code 0805510” manufactured by Toyo Roshi Kaisha Co., Ltd., which changes color due to moisture absorption, and is stored in an environment of 45 ° C. and 80% RH. The degree of color change of the test paper is observed over time. The bag was evaluated for moisture resistance.

(Preparation of coating solution for forming gas barrier resin composition layer)
The preparation of a coating solution for forming a gas barrier resin composition layer used in Examples and Comparative Examples will be described below.

<Preparation of Butenediol / Vinyl Alcohol Copolymer Solution>
In a solvent of 90 parts by mass of purified water, butenediol / vinyl alcohol copolymer (manufactured by Nippon Synthetic Chemical Industry Co., Ltd., trade name: Nichigo G polymer (saponification degree 99.5 mol% or more, average polymerization degree 300), hereinafter, BVOH and Abbreviation) 10 parts by mass was added, heated to 80 ° C. with stirring, and then stirred for about 2 hours. Thereafter, the mixture was cooled to room temperature, thereby obtaining an almost transparent butenediol / vinyl alcohol copolymer solution (BVOH solution) having a solid content of 10%.

<Preparation of polyvinyl alcohol resin solution>
90 parts by mass of purified water, fully saponified polyvinyl alcohol resin (manufactured by Kuraray Co., Ltd., trade name: Kuraray Poval PVA105, (degree of saponification 98.0-99.0 mol%, average degree of polymerization 500), hereinafter abbreviated as PVA) 10 mass Part was added and heated to 80 ° C. with stirring, and then stirred for about 2 hours. Then, it cooled until it became normal temperature, and obtained the substantially transparent polyvinyl alcohol solution (PVA solution) of 10% of solid content by this.

<Preparation of ethylene-vinyl alcohol copolymer solution>
To a mixed solvent of 22.496 parts by mass of purified water and 54.5 parts by mass of n-propyl alcohol (NPA), an ethylene-vinyl alcohol copolymer (manufactured by Nippon Synthetic Chemical Co., Ltd., trade name: Soarnol V2603, ethylene-vinyl acetate co 10 parts by mass of a polymer obtained by saponifying the polymer (ethylene ratio: 26 mol%, saponification degree of vinyl acetate component: approximately 100%, hereinafter abbreviated as EVOH) is added, and a concentration of 30% is added. 13 parts by mass of hydrogen oxide water and 0.004 part by mass of FeSO ₄ were added, heated to 80 ° C. with stirring, and reacted for about 2 hours. Thereafter, the mixture was cooled and catalase was added to 3000 ppm to remove residual hydrogen peroxide, whereby an almost transparent ethylene-vinyl alcohol copolymer solution (EVOH solution) having a solid content of 10% was obtained.

<Additives>
Zirconyl ammonium carbonate (made by Daiichi Rare Elemental Chemical Co., Ltd., trade name: Zircosol AC-7, solid content: about 30%)
Titanium lactate (manufactured by Matsumoto Pharmaceutical Co., Ltd., trade name ORGATICS TC-310, solid content about 45%)

<Preparation of coating liquid for forming gas barrier resin composition layer of Example 1>
Addition of 1.50 parts by weight of titanium lactate (manufactured by Matsumoto Pharmaceutical Co., Ltd., trade name ORGATICS TC-310) to 98.50 parts by weight of the BVOH solution, followed by thorough stirring and mixing to achieve a solid content of about 10% A coating liquid for forming a gas barrier resin composition layer of Example 1 was obtained.

<Preparation of gas barrier resin composition layer forming coating solution of Example 2>
Add 1.50 parts by weight of a zirconium compound (trade name: Zircozol AC-7, solid content: about 30%, manufactured by Daiichi Rare Element Chemical Co., Ltd.) to 98.50 parts by weight of the BVOH solution, and thoroughly stir and mix. A coating solution for forming a gas barrier resin composition layer of Example 2 having a solid content of about 10% was obtained.

<Preparation of gas barrier resin composition layer forming coating solution of Example 3>
100 parts by mass of a BVOH solution was prepared to obtain a gas barrier resin composition layer forming coating solution of Example 3 having a solid content of about 10%.

<Preparation of gas barrier resin composition layer forming coating solution of Comparative Example 1>
Compared to 98.50 parts by mass of the BVOH solution, 1.50 parts by mass of titanium lactate (manufactured by Matsumoto Pharmaceutical Co., Ltd., trade name: ORGATICS TC-310), sufficiently mixed with stirring, and compared with a solid content of about 10%. A coating liquid for forming a gas barrier resin composition layer of Example 1 was obtained.

<Preparation of gas barrier resin composition layer forming coating solution of Comparative Example 2>
0.75 parts by mass of zirconium hydrochloride and 2.25 parts by mass of mixed solvent A are added to 97 parts by mass of the PVA solution, and the mixture is stirred and filtered through a 255 mesh filter to obtain a solid content of 10%. The gas barrier resin composition layer forming coating solution of Comparative Example 2 was obtained.
<Preparation of gas barrier resin composition layer forming coating solution of Comparative Example 3>
To 97 parts by mass of EVOH solution, 0.75 parts by mass of zirconium hydrochloride and 2.25 parts by mass of a mixed solvent composed of 60% by mass of n-propyl alcohol (NPA) (hereinafter referred to as mixed solvent A) are added. Then, the mixture was stirred and filtered through a 255 mesh filter to obtain a gas barrier resin composition layer forming coating solution of Comparative Example 3 having a solid content of about 10%.

<Preparation of gas barrier resin composition layer forming coating solution of Comparative Example 4>
To 97 parts by mass of EVOH solution, 0.75 parts by mass of zirconium hydrochloride and 2.25 parts by mass of a mixed solvent composed of 60% by mass of n-propyl alcohol (NPA) (hereinafter referred to as mixed solvent A) are added. The mixture was stirred and then filtered through a 255 mesh filter to obtain a gas barrier resin composition layer forming coating solution of Comparative Example 4 having a solid content of about 10%.

(Gas barrier laminated films of Examples 1 to 3)
Examples 1 to 3 were formed on an inorganic thin film layer of a biaxially stretched polyester film having a thickness of 12 μm on which a binary oxide inorganic thin film layer of silicon oxide and aluminum oxide (ratio of silicon oxide / aluminum oxide = 40/60) was formed. The gas barrier resin composition of Comparative Example 4 was applied by a gravure roll coating method and dried at 180 ° C. to form a gas barrier resin layer, thereby preparing a gas barrier laminated film.
The thickness of the gas barrier resin layer was 0.25 μm after drying.

(Gas barrier laminated film of Comparative Examples 1 to 4)
Comparative Examples 1 to 3 were formed on an inorganic thin film layer of a biaxially stretched polyester film having a thickness of 12 μm on which a binary oxide inorganic thin film layer of silicon oxide and aluminum oxide (ratio of silicon oxide / aluminum oxide = 60/40) was formed. The gas barrier resin composition was applied by a gravure roll coating method, dried at 180 ° C. to form a gas barrier resin layer, and a gas barrier laminated film was produced.
The thickness of the gas barrier resin layer was 0.25 μm after drying.

  The results are shown in Table 1.

  From the above results, in Comparative Examples 1, 2, and 3, since the water vapor permeability of the inorganic thin film laminate film is large, the water vapor permeability of the gas barrier laminate film is large, and as a result, the moisture resistance of the bag-made product is poor. Moreover, in Comparative Example 4, since the humidity dependency of the water vapor permeability of the gas barrier resin composition layer was small, the water vapor permeability of the gas barrier laminated film was large, resulting in poor moisture resistance in the bag-made product.

  According to the present invention, it is possible to obtain a gas barrier laminated film having an interlayer adhesive force for expressing a necessary minimum laminate strength as a packaging bag while having a high gas barrier property against oxygen, water vapor and the like. In addition, it is possible to stably produce a highly practical gas barrier laminated film suitable for moisture-proof packaging for protecting the contents from external humidity. The gas barrier film of the present invention can be widely used for packaging applications such as confectionery, daily necessities, electronic parts, pharmaceuticals, etc. that require moisture resistance to protect against moisture from the outside, and industrial applications such as vacuum insulation materials. it can.

Claims (4)

A gas barrier laminate film obtained by laminating an inorganic thin film layer and a gas barrier resin composition layer on at least one surface of a base film, wherein the gas barrier resin composition layer is polyvinyl alcohol or butenediol-vinyl alcohol copolymer The base film on which the inorganic thin film layer is laminated and has a water vapor permeability of 0.9 g / m ² · d or less at 40 ° C. and 90% RH, and the gas barrier resin composition layer is 40 ° C. A gas barrier laminate film comprising a highly moisture-dependent film having a water vapor barrier property ratio of 15 to 100 times at 35% RH and 40 ° C. and 90% RH.   The gas barrier laminate film according to claim 1, wherein the additive added to the gas barrier resin composition layer contains at least one hydrogen bonding group crosslinking agent.   The gas barrier laminate film according to claim 1 or 2, wherein the inorganic thin film layer contains at least one multi-component inorganic oxide containing silicon oxide and aluminum oxide.   A gas barrier packaging bag in which the gas barrier laminate film according to any one of claims 1 to 3 is arranged in the order of a base film layer, an inorganic thin film layer, and a gas barrier resin composition layer from the outside of the bag.