JP2017177357A - Gas barrier laminate - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a laminate having a barrier property against an inert gas such as helium.SOLUTION: A gas barrier laminate includes, laminated on a plastic substrate: a metal oxide layer of at least 1-100 nm; a barrier film having a layer including polyvinyl alcohol of 20-1000 nm; and a film at least having heat sealability. A helium permeation rate at 40°C 0% is 2000 cc/mday atm or less and an oxygen permeation rate at 30°C 70% is 3.0 cc/mday atm or less.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a gas barrier film laminate.

  Packaging for food, electronic parts, and other packaging is highly confidential, and packaging materials using various plastic films, metal foil, paper, and other materials have been developed to prevent the deterioration of contents due to moisture and oxygen. Moreover, the packaging material which can be made into a bag shape by laminating with the film which can be sealed is obtained. The contents include those that are sensitive to moisture and oxygen, but in order to prevent deterioration of the contents such as oxidation, an inert gas such as helium or argon, which is a low-reactivity gas, is placed inside the bag. There is a need to make it difficult for gas to escape. In addition, a balloon filled with helium is generally used as the lightest gas, and a film having a helium barrier property is used so as not to dissipate helium. For example, Patent Document 1 discloses a film using an ethylene-vinyl alcohol copolymer as a barrier layer as a balloon film. However, oxygen barrier properties are not considered.

  Moisture (water vapor) barrier properties can be slightly compensated by the physical properties of the film that can be sealed, but oxygen barrier properties cannot be compensated. Conventionally, polyvinyl alcohol and ethylene vinyl alcohol have a film shape. The method of laminating is taken, but there is a problem in cost because it has to be a thick film.

JP-A-2-43036

  Provided is a gas barrier laminate that can be manufactured by an inexpensive method in order to produce a packaging material that does not transmit small monoatomic molecules such as helium and that also barriers oxygen.

A first aspect of the present invention is a barrier film comprising a metal oxide layer of at least 1 to 100 nm and a layer containing 20 to 1000 nm of polyvinyl alcohol on a plastic substrate, and a film having at least heat sealability. Is a gas barrier laminate in which a helium permeability at 40 ° C. and 0% is 2000 cc / m ² · day · atm or less and an oxygen permeability at 30 ° C. and 70% is 3.0 cc / m ² · day · atm or less. is there.

The second aspect of the present invention is the gas barrier laminate according to claim 1, wherein the argon permeability of the barrier film is 3.0 cc / m ² · day · atm or less.

Third aspect of the present invention further oxygen permeability 3.0cc ^/ m 2 · day · helium permeability at less and ^{30 ℃ 70% 2000cc / m 2} · day · atm at 40 ° C. 0% of the barrier film The gas barrier laminate according to claim 1 or 2, which is atm or less.

  The fourth aspect of the present invention is characterized in that the metal oxide layer further contains Al atoms.

  In the fifth aspect of the present invention, the heat-sealable film is a film that exhibits heat-sealability at a temperature of 100 ° C. or higher.

  The gas barrier laminate according to the present invention can produce a barrier laminate that does not transmit rare gases such as helium and argon, which are small atoms, and has high oxygen barrier properties.

It is the schematic which shows the one aspect | mode of the gas barrier laminated body of this invention. It is the schematic which shows the two aspects of the gas barrier laminated body of this invention.

  1 is a barrier film in which a metal oxide layer 2 and a layer 3 containing polyvinyl alcohol are laminated in this order on one surface of a plastic substrate 1. 10, a heat-sealable film 5 is laminated via an adhesive layer 4. A coat layer may be provided between the plastic base metal oxide layers. The adhesive layer 4 is not necessary when the film 5 having a direct heat sealability and the barrier film are directly attached. The film having heat sealability may be laminated on the other surface of the plastic substrate.

  Examples of the plastic substrate 1 used in the present invention include polyolefin resins such as polyethylene and polypropylene; polyester resins such as polyethylene terephthalate, polyethylene isophthalate, polyethylene-2,6-naphthalate, and polybutylene terephthalate; Ether resins, polyamide resins such as nylon-6 and nylon-6, 6, polycarbonate resins, polyimide, polyetherimide, polyether sulfone, polysulfone, polyether ether ketone, polyether ketone ketone, and the like can be used. These resins may be homopolymers or copolymers, or those formed by melting and mixing one or more resins into a film shape. If necessary, the base film can be processed, heat-resistant, weather-resistant, mechanical properties, dimensional stability, anti-oxidation, slipperiness, release properties, flame retardancy, anti-mold, electrical Various plastic compounding agents, additives, and the like can be added for the purpose of improving and modifying characteristics, strength, and the like, and the addition amount can be arbitrarily added according to the purpose.

  In the present invention, among the above resin films or sheets, it is particularly preferable to use a polyester resin, a polyolefin resin, or a polyamide resin film or sheet. The stretchable film may be biaxially stretched or uniaxially stretched, but biaxial stretching is more preferable in order to provide thermal stability. Although the thickness of a base material is not specifically limited, A thing of about 6 micrometers-200 micrometers can be used according to a use.

  The base material may be provided with various pretreatments such as corona treatment, plasma treatment and flame treatment, and a coating layer such as an easy adhesion layer. Separately, a coating layer may be applied to reduce the unevenness of the substrate.

  Examples of such coating agents include acrylic resins, epoxy resins, acrylic urethane resins, polyester polyurethane resins, and polyether polyurethane resins. Among these coating agents, acrylic urethane resins and polyester polyurethane resins are preferable from the viewpoint of heat resistance and interlayer adhesion strength.

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

Furthermore, as an application amount of such a coating agent, it is preferable that the mass per 1 m ² after coating and drying the coating agent is 0.01 to 10 g / m ² , and 0.03 to 5 g / m ^2. more preferably m ^2. If the mass per 1 m 2 after coating and drying the coating agent is less than the lower limit, film formation tends to be insufficient. On the other hand, if the upper limit is exceeded, drying is insufficient and the solvent tends to remain. There is a tendency.

  The material of the film 5 having heat sealability at a temperature of 100 ° C. or higher may be any material that can be melted by heat and fused to each other, for example, low density polyethylene, medium density polyethylene, high density polyethylene, linear (Linear) Low density polyethylene, polypropylene, ethylene-vinyl acetate copolymer, ionomer resin, ethylene-ethyl acrylate copolymer, ethylene-acrylic acid copolymer, ethylene-methacrylic acid copolymer, ethylene-propylene copolymer Polyolefin resins such as polymers, methylpentene polymers, polyethylene and polypropylene, or resins such as acid-modified polyolefin resins obtained by modifying these resins with unsaturated carboxylic acids such as acrylic acid, methacrylic acid, maleic anhydride, and fumaric acid A resin film or sheet comprising one or more of It can be used.

  The thickness of the film 5 having heat sale properties is preferably 20 μm to 150 μm. If it is too thin, there will be no stiffness and it will be difficult to handle.

  The heat-sealable film 5 may be bonded via an adhesive resin layer by melt extrusion, or may be bonded via an adhesive by a processing method such as dry lamination, wet lamination, or solventless lamination. Examples of the adhesive resin by melt extrusion include polypropylene, polyethylene, and modified resins thereof, and the thickness is desirably about 5 μm to 50 μm. When pasting together with an adhesive, it is applied, dried and cured by a general coating method using an acrylic, urethane or rubber adhesive. In some cases, UV / EB may be irradiated and cured. The thickness of the adhesive is desirably about 1 to 20 μm.

  The layer containing the Group 13 or Group 14 element used in the present invention may be a multilayer, but at least one layer needs to be formed by vacuum film formation. In vacuum film formation, physical vapor deposition or chemical vapor deposition can be used. Examples of physical vapor deposition include, but are not limited to, vacuum vapor deposition, sputter vapor deposition, and ion plating. Examples of chemical vapor deposition include, but are not limited to, thermal CVD, plasma CVD, and photo CVD.

  Here, in particular, a resistance heating vacuum deposition method, an EB (Electron Beam) heating vacuum deposition method, an induction heating vacuum deposition method, a sputtering method, a reactive sputtering method, a dual magnetron sputtering method, a plasma chemical vapor deposition method ( PECVD method) is preferably used.

  In the items after the above sputtering method, plasma is used, but plasma such as DC (Direct Current) method, RF (Radio Frequency) method, MF (Middle Frequency) method, DC pulse method, RF pulse method, DC + RF superposition method, etc. Can be mentioned.

  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. Therefore, MW (Micro Wave) plasma is not suitable for sputtering because self-bias does not occur. However, in the PECVD method, a chemical reaction, deposition, and a process proceed using a gas phase reaction in plasma, so that a film can be generated without self-bias, and thus MW plasma can be used.

  Examples of the metal oxide layer 2 used in the present invention include oxides such as silicon, aluminum, tin, and indium. Among them, silicon oxide (SiOx, x = 1.0 to 2.0) or aluminum oxide (AlOx, x = 1.45 to 2.0) or a mixed layer thereof is desirably used, and other atoms such as nitrogen and carbon may be contained. Among others, the present inventor has found that an aluminum oxide film is suitable for the barrier property of helium.

  The metal oxide layer 2 in the present invention is preferably 5 nm or more and 100 nm or less, and more preferably 10 n or more and 50 nm or less. If the film thickness is less than 5 nm, sufficient water vapor barrier performance cannot be obtained. On the other hand, if the cured film thickness is larger than 100 nm, cracks are generated due to an increase in curing shrinkage, and the water vapor barrier property is lowered. Furthermore, the cost increases due to an increase in the amount of material used, a longer film formation time, etc., which is not preferable from an economic viewpoint.

  For the layer 3 containing polyvinyl alcohol, those having various polymerization degrees and saponification degrees can be used, but those having a saponification degree of 85% or more are desirable for obtaining barrier properties. In general, a material dissolved in water is often used as a coating material. However, in the present invention, it is desirable to apply a coating material with an alcohol added thereto. Generally, alcohols having C1-C4 carbon number such as methanol, ethanol, isopropyl alcohol, normal propyl alcohol, normal butyl alcohol, isobutyl alcohol, sec-butyl alcohol, tert-butyl alcohol are preferable for the purpose of drying. However, for the purpose of curing acceleration, there are ethylene glycol, trimethylene glycol, tetramethylene glycol, pentamethylene glycol, hexamethylene glycol, propylene glycol, glycerin, butanediol, diethylene glycol, triethylene glycol and the like.

  To the layer 3 containing polyvinyl alcohol, other compounds may be added for the purpose of curability, adhesion, and heat resistance, and it is particularly desirable that the layer be water-soluble. For example, methyl cellulose, polyacrylic acid compounds, polyurethane compounds, clay minerals, pyrrolidone compounds, metal oxides using metal precursors, and the like.

  A metal oxide using a metal precursor preferably forms a film mainly as a reaction of a silanol group as Si, and generally R1 (Si-OR2) includes tetramethoxysilane, tetraethoxysilane, tetrapropoxy. Examples of the raw material include silanes such as silane, tetrabutoxysilane, methyltrimethoxysilane, methyltriethoxysilane, dimethyldimethoxysilane, and dimethyldiethoxysilane. R1 (Ti-OR2) in which the metal atom is Ti, specifically, tetramethoxytitanium, tetraethoxytitanium, tetraisopropoxytitanium, and tetrabutoxytitanium can be given. Polysilazane containing nitrogen may be used. Further, R1 (Al-OR2) in which the metal atom is Al, specifically, tetramethoxyaluminum, tetraethoxyaluminum, tetraisopropoxyaluminum, tetrabutoxyaluminum, or R1 (Zr-OR2) in which the metal atom is Zr. Examples thereof include tetramethoxyzirconium, tetraethoxyzirconium, tetraisopropoxyzirconium, tetrabutoxyzirconium, and the like.

  The layer containing polyvinyl alcohol is preferably 20 nm to 1000 nm, more preferably 50 nm to 500 nm, and particularly preferably 100 nm to 400 nm. If the thickness is too thin, the oxygen barrier property will not be exhibited, and if it is too thick, the shrinkage stress is too large, causing cracks in the metal oxide layer and deteriorating the barrier property.

  A plurality of the metal oxide layer 2 and the layer 3 containing polyvinyl alcohol may be laminated. In particular, as shown in FIG. 2, by alternately laminating the metal oxide layer 2 of the barrier film 20 and the layer 3 containing polyvinyl alcohol, the oxygen barrier property and the barrier property against helium and argon can be remarkably improved. it can.

In the barrier films 10 and 20 having the above configuration, the helium permeability at 40 ° C. and 0% (measurement conditions are temperature of 40 ° C. and humidity of 0%) is 2000 cc / m ² · day · atm or less, and oxygen transmission at 30 ° C. and 70%. A barrier film having a degree of 3.0 cc / m ² · day · atm or less can be obtained. By forming a gas barrier laminate in which such a barrier film and a heat-sealable film are bonded together, oxygen can be obtained. A gas barrier laminate that does not penetrate and suppresses the emission of helium can be obtained.

In the barrier film having the above structure, the argon permeability at 40 ° C. 0% (measurement conditions are temperature 40 ° C., humidity 0%) is 3.0 cc / m ² · day · atm or less, and the oxygen permeability at 30 ° C. 70%. Can be used as a barrier film having a thickness of 3.0 cc / m ² · day · atm or less. By forming a gas barrier laminate in which such a barrier film and a heat-sealable film are bonded together, oxygen can enter. Without causing the gas barrier laminate to suppress the diffusion of argon.

Furthermore, the helium permeability at 40 ° C. and 0% is 2000 cc / m ² · day · atm or less, and the argon permeability at 40 ° C. and 0% is 3.0 cc / m ² · day · atm or less. It can be set as the gas barrier laminated body provided with both of these barrier properties.

  As described above, since the gas barrier laminate has both the oxygen barrier property and the inert gas barrier property of the present invention, it can be suitably used as a packaging material, for example. Specifically, the quality of the contents can be maintained over a long period of time by sealing with helium or argon gas filled with the contents.

  Specific examples of the present invention will be described below.

[Example 1]
A biaxially stretched polyethylene terephthalate was cured with 0.1 g / m ² of a polyester resin, and aluminum was evaporated while introducing oxygen by an electron beam vacuum deposition method to form an AlOx deposited film having a thickness of 10 nm. A coating solution in which polyvinyl alcohol was mixed with water / isopropyl alcohol was applied thereon, followed by drying and curing at 120 ° C. to form a cured film having a thickness of 150 nm. Furthermore, it bonded with the 60-micrometer LDPE film through the adhesive agent on the cured film formation surface of the barrier film.
The oxygen permeability of the film was 0.9 cc / m ² · day · atm, and the helium permeability was 100 cc / m ² · day · atm.

[Reference example]
A biaxially stretched polyethylene terephthalate was cured with 0.1 g / m ² of a polyester resin, and aluminum was evaporated while introducing oxygen by an electron beam vacuum deposition method to form an AlOx deposited film having a thickness of 10 nm. A coating liquid in which a hydrolyzate of tetraethoxysilane and polyvinyl alcohol were mixed was applied thereon and dried and cured at 120 ° C. to form an organic-inorganic hybrid film having a thickness of 0.3 μm. The oxygen permeability of the film was 0.8 cc / m ² · day · atm, and the helium permeability was 300 cc / m ² · day · atm.

[Example 2]
A biaxially stretched polyethylene terephthalate was cured with 0.1 g / m ² of a polyester resin, and aluminum was evaporated while introducing oxygen by an electron beam vacuum deposition method to form an AlOx deposited film having a thickness of 10 nm. A coating liquid in which a hydrolyzate of tetraethoxysilane and polyvinyl alcohol were mixed was applied thereon and dried and cured at 120 ° C. to form an organic-inorganic hybrid film having a thickness of 0.3 μm. Furthermore, it bonded with the 60 micrometer LDPE film with the adhesive agent through the adhesive agent on the cured film formation surface of the barrier film. The oxygen permeability of the film was 0.5 cc / m ² · day · atm, and the helium permeability was 200 cc / m ² · day · atm.

[Example 3]
Polyester resin is cured to a solid content film thickness of 0.1 g / m ^{2 on} biaxially stretched polyethylene terephthalate, and an SiOx vapor deposition film with a thickness of 30 nm is formed by an electron beam vacuum vapor deposition method using a SiO evaporation source. did. A coating liquid in which a hydrolyzate of tetraethoxysilane and polyvinyl alcohol were mixed thereon was applied and dried and cured at 120 ° C. to form an organic-inorganic hybrid film. Furthermore, it bonded with the 60-micrometer LDPE film through the adhesive agent on the cured film formation surface of the barrier film. The oxygen permeability of the film was 0.5 cc / m ² · day · atm, and the helium permeability was 1500 cc / m ² · day · atm.

[Example 4]
Polyester resin is cured on biaxially stretched polyethylene terephthalate so as to have a solid film thickness of 0.1 g / m ² , and aluminum is evaporated while introducing oxygen by an electron beam vacuum deposition method. A deposited film was formed. A coating liquid in which a hydrolyzate of tetraethoxysilane and polyvinyl alcohol were mixed was applied thereon and dried and cured at 120 ° C. to form an organic-inorganic hybrid film having a thickness of 0.3 μm. Further, an AlOx vapor deposition film having a thickness of 10 nm was formed on the hybrid film. A 60 μm LDPE film was bonded to the cured film-forming surface of the barrier film via an adhesive. The oxygen permeability of the film was 0.2 cc / m ² · day · atm, the helium permeability was 50 cc / m ² · day · atm, and the argon permeability was 0.2 cc / m ² · day · atm.

[Comparative Example 1]
A polyester resin was cured to 0.1 g / m ^{2 on a} biaxially stretched polyethylene terephthalate film, and aluminum was evaporated while introducing oxygen by an electron beam vacuum deposition method to form an AlOx deposited film having a thickness of 10 nm.
Furthermore, it bonded with the 60-micrometer LDPE film through the adhesive agent on the cured film formation surface of the barrier film. The oxygen permeability of the film was 3.5 cc / m ² · day · atm, and the helium permeability was 500 cc / m ² · day · atm.

[Comparative Example 2]
Biaxially stretched polyethylene terephthalate was coated with a coating solution in which polyvinyl alcohol was mixed with water / isopropyl alcohol, and dried and cured at 120 ° C. to form a cured film having a thickness of 150 nm. Furthermore, it bonded with the 60 micrometer LDPE film with the adhesive agent through the adhesive agent on the cured film formation surface of the barrier film. The oxygen permeability of the film was 22 cc / m ² · day · atm, and the helium permeability was 5000 cc / m ² · day · atm.

[Comparative Example 3]
A biaxially stretched polyethylene terephthalate was cured with 0.1 g / m 2 of a polyester resin, and aluminum was evaporated while introducing oxygen by an electron beam vacuum deposition method to form an AlOx deposited film having a thickness of 10 nm. A coating liquid in which a hydrolyzate of tetraethoxysilane and polyvinyl alcohol were mixed thereon was applied and dried and cured at 120 ° C. to form an organic-inorganic hybrid film having a thickness of 1.5 μm. Furthermore, it bonded with the 60-micrometer LDPE film through the adhesive agent on the cured film formation surface of the barrier film. The oxygen permeability of the film was 1.0 cc / m ² · day · atm, the helium permeability was 3000 cc / m ² · day · atm, and the argon permeability was 3000 cc / m ² · day · atm.

Evaluation of gas barrier properties: [Measurement method of oxygen permeability]
Using an oxygen permeability measuring device (OXTRAN 2/20 manufactured by Modern Control), the measurement was performed under conditions of a temperature of 30 ° C. and a relative humidity of 70%. The measurement method was measured in accordance with JIS K-7126, method B (isobaric method).
The helium permeability and argon permeability were measured with Yanaco GTR-30XT by a differential pressure method according to JIS K 7126 A method at a temperature of 40 ° C. and a relative humidity of 0%.

  As shown in Table 1, in Examples 1 to 4, oxygen permeability, helium permeability, and argon permeability are low and barrier properties are good, but in Comparative Examples 1 to 3, any or all gas permeability is high. , Barrier property is low. In particular, as shown in the results of claims 1, 2, and 4, the helium permeability in the AlOx deposited film was low and the helium barrier property was good.

  The gas barrier laminate of the present invention can be used as an appropriate packaging member having both a helium barrier or an argon barrier and an oxygen barrier by a combination of a metal oxide layer and polyvinyl alcohol.

1 Plastic substrate 2 Metal oxide layer (gas barrier layer)
3 Layer containing polyvinyl alcohol 4 Adhesive layer 5 Heat-sealable film 10, 20 Barrier film 100, 200 Gas barrier laminate

Claims (5)

On the plastic substrate, a barrier film comprising a metal oxide layer of at least 1 to 100 nm, a layer containing 20 to 1000 nm of polyvinyl alcohol, and at least a heat-sealable film are laminated, and 40 ° C. 0% Gas barrier laminate having a helium permeability of 2000 cc / m ² · day · atm or less and an oxygen permeability of 30 cc / 70% at 70% of 3.0 cc / m ² · day · atm or less. The gas barrier laminate according to claim 1, wherein the argon permeability is 3.0 cc / m ² · day · atm or less. ^3. The helium permeability at 40 ° C. and 0% of the barrier film is 2000 cc / m ² · day · atm or less, and the oxygen permeability at 30 ° C. and 70% is 3.0 cc / m ² · day · atm or less. A gas barrier laminate as described in 1.   The barrier film according to any one of claims 1 to 3, wherein the metal oxide layer contains Al atoms, and the laminate thereof.   The laminate according to any one of claims 1 to 4, wherein the heat-sealable film is a film that exhibits heat-sealability at a temperature of 100 ° C or higher.

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